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12,199,703 | https://en.wikipedia.org/wiki/Process%20manufacturing | Process manufacturing is a branch of manufacturing that is associated with formulas and manufacturing recipes, and can be contrasted with discrete manufacturing, which is concerned with discrete units, bills of materials and the assembly of components. Process manufacturing is also referred to as a 'process industry' which is defined as an industry, such as the chemical or petrochemical industry, that is concerned with the processing of bulk resources into other products.
Process manufacturing is common in the food, beverage, chemical, pharmaceutical, nutraceutical, consumer packaged goods, cannabis, and biotechnology industries. In process manufacturing, the relevant factors are ingredients, not parts; formulas, not bills of materials; and bulk materials rather than individual units. Although there is invariably cross-over between the two branches of manufacturing, the major contents of the finished product and the majority of the resource intensity of the production process generally allow manufacturing systems to be classified as one or the other. For example, a bottle of juice is a discrete item, but juice is process manufactured. The plastic used in injection moulding is process manufactured, but the components it is shaped into are generally discrete, and subject to further assembly.
Examples of process industries
Bulk-drug pharmaceuticals
Chemical, tire, and process industries (CTP)
Cosmeceuticals and personal care
Food and beverage, Food processing
Nutraceuticals
Paints and coatings
Semiconductor fabrication
Specialty chemicals
Steel and aluminium processing
Textiles
Formulation
Formulation is a simple concept, but it is often incorrectly equated with a bill of materials. Formulation specifies the ingredients and the amounts (e.g., pounds, gallons, liters) needed to make the product. The first thing to recognize is that to be able to work with a formula, the units of measure must correspond; a flexible unit of measure conversion engine running under an ERP software cover is needed. Furthermore, conversion rules must be specified to account for the unique requirements of the business in question. This formulation then needs to be scaled up to the development and then manufacturing scales, and must often be transferred and validated in different manufacturing sites around the world.
The proportions of ingredients in a formula also highlight the need for another feature, namely scalability. A formula to make 500 liters of a chemical must be scalable to make 250 liters or 1,000 liters. Another aspect of scalability is that it makes possible manufacturing based on how much of an ingredient is available. An example will illustrate this point. If you are making a car and only have two of the required four tires, you cannot make half a car. In other words, you must have all the parts in the required quantities to make the finished product; they are not scalable. But in process manufacturing, if you want to make 1,000 gallons of soda and you only have 500 gallons of the required 1,000 gallons of carbonated water, you have the option of making half as much soda. In process manufacturing you can make as much of a finished product as is specified in the formula for the smallest quantity in stock of one of the ingredients.
Packaging
A packaging recipe is similar to a formula, but rather than describing the proportion of ingredients, it specifies how the finished product gets to its final assembly. A packaging recipe addresses such things as containers, labels, corrugated cartons, and shrink-wrapping. In process manufacturing, the finished product is usually produced in bulk, but is rarely delivered in bulk form to the customer. For example, the beverage manufacturer makes soda in batches of thousands of gallons. However, a consumer purchases soda in 12-ounce aluminum cans, or in 16-ounce plastic bottles, or in 1-liter bottles. And a restaurateur may have the option of getting a 5- or 50-gallon metal container with the beverage in syrup form, so that carbonated water can be added later.
Why is this concept important? Compare how often Coca-Cola changes the formula for Coke with how often the packaging is changed. If the formula and packaging recipes are linked, then every time the packaging changes, the formula would need modification. Likewise, when the formula is changed, all of the packaging recipes would have to be changed. This increases maintenance costs and chances for error. In process manufacturing, the formula for making the product and the recipe for packaging the product exist in separate structures to reduce the ongoing maintenance function. There is a difference between discrete manufacturing and process manufacturing in terms of flow patterns. An example given is that discrete manufacturing follows an "A" type process and process manufacturing follows a “V” type process.
In the production cycle, a work order or process order is issued to make the product in bulk. Separate pack orders are issued to signify how the bulk material is to be containerized and shipped to the customer. This is important in process industries that make “brite” stock or private labels. For example, large grocery chains sell products, such as soups, soda, and meats, under their own brand names, hence "private labels". But these chains do not have their own manufacturing plants; they contract for these products. In the case of soups, process manufacturers create and warehouse nondescript, unlabeled (hence “brite”) aluminum cans of soup. (Since the cans are filled, sealed, and then cooked under pressure, their shelf life is long.)
By separating the product formula from a packaging recipe, a production or process order can be issued to make and store the cans of soup and later, when the customer is ready to order soup, a work order can be issued to label the cans according to customer specifications before they are shipped to the store. Thus segregation of the formula and pack recipe makes the world of process manufacturing efficient and effective.
Process manufacturing systems and methodologies
Enterprise resource planning
Just like the products that they produce, discrete manufacturing and process manufacturing use different Enterprise resource planning (ERP) systems which have different focal points and solve different problems. For the same reason that the proverbial square peg does not fit in the round hole, ERP software geared toward discrete manufacturing, or even hybrid manufacturing will not work smoothly in a process manufacturing setting. With process manufacturing, the end-product is unable to be broken down to its original ingredients, for example beer or pasta sauce. Thus, the ERP software must be able to account for these intricacies in its ability to convert and transform raw materials to finished goods. Critical aspects such as recipe formulation, forward and backward lot traceability, handling of mixed units of measure and conversion, raw material calculations, and scalable batch tickets with revision tracking and recording of manufacturing steps and production notes are specific to process manufacturers and key functionality of process manufacturing ERP systems. An example is the SAP module, Production Planning - Process Industries (PP-PI).
In Process Inspections and Statistical Process Control
In process inspection for process manufacturing refers to inspection at any point in producing a product, and is also referred to as in process product verification. The objective of in process inspection is to ensure the requirements of the product are being met before they are finalized and continue to the next stage. Identifying a problem at an early stage in the production process allows for correction and preventative action to avoid wasted time and resources at the end of a production run.
Statistical Process Control complements process manufacturing and in process inspections to ensure that the process operates efficiently, producing more specification-conforming products with less waste (rework or scrap).
Process approach in Management Systems
The process approach is one of seven quality management principles that ISO management system standards are based on, and includes establishing the organization’s processes to operate as an
integrated and complete system.
In Food processing, complying product has to come from a process to comply, in comparison to discrete manufacturing where a finished product is inspected to comply. An example how the process approach complements a process industry is implementation of ISO 22000 as a Food Safety Management System (FSMS). The process approach involves the systematic definition and management of processes, and their interactions, so as to achieve the intended results in accordance with the food safety policy and strategic direction of the organization. Management of the processes and the system as a whole can be achieved using the PDCA cycle, with an overall focus on risk-based thinking aimed at taking advantage of opportunities and preventing undesirable results.
References
Manufacturing
Further reading
Salimi, Fabienne; Salimi, Frederic, A Systems Approach to Managing the Complexities of Process Industries, 2017 | Process manufacturing | Engineering | 1,714 |
11,157,848 | https://en.wikipedia.org/wiki/FLUKA | FLUKA (FLUktuierende KAskade) is a fully integrated Monte Carlo simulation package for the interaction and transport of particles and nuclei in matter.
FLUKA has many applications in particle physics, high energy experimental physics and engineering, shielding, detector and telescope design, cosmic ray studies, dosimetry, medical physics, radiobiology. A recent line of development concerns hadron therapy.
It is the standard tool used in radiation protection studies in the CERN particle accelerator laboratory.
FLUKA software code is used by Epcard, which is a software program for simulating radiation exposure on airline flights.
Comparison with other codes
MCNPX is slower than FLUKA.
Geant4 is slower than FLUKA.
References
Further reading
External links
Official site of FLUKA collaboration
FLUKA on the CERN bulletin
Physics software used to fight cancer
Fortran software
Physics software
Monte Carlo molecular modelling software
Science software for Linux
Linux-only proprietary software
CERN software
Monte Carlo particle physics software
Proprietary commercial software for Linux | FLUKA | Physics | 201 |
65,289,853 | https://en.wikipedia.org/wiki/Teachability%20Hypothesis | The Teachability Hypothesis was produced by Manfred Pienemann. It was originally extracted from Pienemann's Processibility model. It proposes that learners will acquire a second language (L2) features if what is being taught is relatively close to their stage in language development.
Description
The Teachability Hypothesis is based on previous psycholinguistic research in second language acquisition done by Meisel, Clahsen, and Pienemann (1981) and is reflective in Pienemann's Processibility theory. The hypothesis reports that some aspects of language are sequenced in a way that follows the developmental levels of language in which Pienemann coined those these features as 'developmental'. This sequence is reflective of the natural stages that learners will go through when learning a second language. Pienemann (1984) emphasizes that teachability of L2 structures have psychological constraints are universally shared. Language sequences have been reflected in wh-questions, some grammatical morphemes, negation, possessive determiners, and relative clause. Other features that do not have a developmental level of acquisition and can be acquired at any point in time Pienemann called 'variational' features. Pienemann (1981) concludes that formal instruction needs to be directed towards the ‘natural’ process of second language acquisition.
In Pienemann's (1984, 1998) study, he predicted that by following the natural order hypothesis, learners must pass through a set sequence of stages when acquiring language features. However, the instruction is only effective if the learners' interlanguage is close to the step of acquiring that structure Pienemann (1984, 1989, 1998). In addition to following natural acquisition order Pienemann (2013) argued that natural order of acquisition is unbeatable. Thus, instruction cannot make a learner to skip a stage. This means that a learner who is classified at stage 2 in a specific language feature will not benefit from instruction that is directed at learners who are at stage 4. Although, learners who are at stage 3 in a specific language feature may benefit from instruction that is directed at learners who are at stage 4. The reasoning for this is based on the learner's readiness.
Implications: Readiness
A barrier that the teachability Hypothesis mentions that can prevent the natural development of language acquisition is 'readiness'. Second language learners will not develop and progress through the same stages at the same time. This means that a learner's readiness refers to when a learner is able to move on to the next stage in the sequence of a particular language. The teachability Hypothesis has been used by second language researchers to understand student readiness in acquiring specific linguistic abilities.
Importance
Second language education
The teachability hypothesis provides reasoning for the varied rate at which second languages are acquired. This hypothesis allows educational professionals such as, second language instructors to gain a sense of reasoning as to why their learners may or may not be succeeding as rapidly as their peers. It also documents the importance of teaching to a certain developmental level rather than a standard level or to age. Educational professionals can apply Pienemann's (1988) conclusion of second language learning to their lessons by designing targeted instructions to be conscientious towards student readiness for the outcome of the target learning to be successful.
Second language acquisition research
The Teachability Hypothesis is important to the framework of psycholinguistic theories as it examines the reasoning as to why learners linguistic capabilities may not be developing at the same rate as other learners. In addition, Second language researches have been studying issues around language pedagogy. Common issues in which the Teachability Hypothesis has provided an explanation is whether and to what degree instruction helps in second language acquisition. Second language acquisition researchers will often position themselves on a scale of the importance of instruction and innate learning. There are four main positions (1) interface position, (2) Variability Hypothesis, (3) Weak Interface Position, and (4) the Teachability Hypothesis. The Teachability Hypothesis favours teaching according to natural development, it has supported second/foreign language pedagogies teaching approaches such as the Learning-Centered approach. It has also supported classroom structure, instruction time, and use of first language in the classroom. Through these perspectives on language acquisition, second language processing can be understood.
Supporting research
Comparing teaching approaches to the Teachability Hypothesis
References
Cognitive psychology | Teachability Hypothesis | Biology | 878 |
43,707,796 | https://en.wikipedia.org/wiki/Channel%20modulator | A channel modulator, or ion channel modulator, is a type of drug which modulates ion channels. They include channel blockers and channel openers.
Direct modulators
Ion channels are typically categorised by gating mechanism and by the ion they conduct. Note that an ion channel may overlap between different categories. Some channels conduct multiple ion currents and some are gated by multiple mechanisms.
Examples of targets for modulators include:
Voltage-gated ion channels
Calcium channel: see also Calcium channel blocker, Calcium channel opener
Potassium channel: see also Potassium channel blocker, Potassium channel opener
Sodium channel: see also Sodium channel blocker, Sodium channel opener
Chloride channel: see also Chloride channel blocker, Chloride channel opener
Transient receptor potential channel
Ligand gated ion channels
5-HT3: see also 5-HT3 antagonist,
GABAA receptor: see also GABA receptor agonist, GABA receptor antagonist
Glutamate receptor: see also Excitatory amino acid receptor agonist, Excitatory amino acid receptor antagonist, Ionotropic glutamate receptor, Ampakine, NMDA receptor antagonist
Nicotinic receptor: see also Nicotinic agonist, Ganglionic blocker and Neuromuscular-blocking drug)
Ion channels gated by other mechanisms (e.g. light gated and mechanosensitive ion channels). These types of channels can also be pharmacologically modulated. For lists of the substances that pharmacologically modulate them, see their respective articles.
Indirect modulators
Ion channels can also be modulated indirectly. For example with G protein coupled receptors (GPCRs), for G protein coupled inward rectifier potassium channels (GIRKs) and M channels. Ion channels can also be modulated by reuptake inhibitors and releasing agents.
See also
Enzyme modulator
Receptor modulator
Transporter modulator
References
Membrane transport modulators | Channel modulator | Chemistry | 400 |
47,049,674 | https://en.wikipedia.org/wiki/Polemovirus | Polemovirus is a genus of viruses. Commercial cultivars of Euphorbia pulcherrima serve as natural hosts. There is only one species in this genus: Poinsettia latent virus. Its RNA suggests a replication mode like that of poleroviruses, whereas the coat protein sequence is closely related to that of sobemoviruses.
Structure
Viruses in Polemovirus are non-enveloped, with icosahedral geometries, and T=3 symmetry. Genomes are linear and non-segmented.
Life cycle
Viral replication is cytoplasmic, and is lysogenic. Entry into the host cell is achieved by penetration into the host cell. Replication follows the positive stranded RNA virus replication model. Positive stranded RNA virus transcription is the method of transcription. The virus exits the host cell by tubule-guided viral movement.
Commercial cultivars of Euphorbia pulcherrima serve as the natural host.
References
External links
ICTV
Positive-sense single-stranded RNA viruses
Riboviria
Virus genera | Polemovirus | Biology | 217 |
4,098,482 | https://en.wikipedia.org/wiki/Bergman%20cyclization | The Masamune-Bergman cyclization or Masamune-Bergman reaction or Masamune-Bergman cycloaromatization is an organic reaction and more specifically a rearrangement reaction taking place when an enediyne is heated in presence of a suitable hydrogen donor (Scheme 1). It is the most famous and well-studied member of the general class of cycloaromatization reactions. It is named for Japanese-American chemist Satoru Masamune (b. 1928) and American chemist Robert G. Bergman (b. 1942). The reaction product is a derivative of benzene.
The reaction proceeds by a thermal reaction or pyrolysis (above 200 °C) forming a short-lived and very reactive para-benzyne biradical species. It will react with any hydrogen donor such as 1,4-cyclohexadiene which converts to benzene. When quenched by tetrachloromethane the reaction product is a 1,4-dichlorobenzene and with methanol the reaction product is benzyl alcohol.
When the enyne moiety is incorporated into a 10-membered hydrocarbon ring (e.g. cyclodeca-3-ene-1,5-diyne in scheme 2) the reaction, taking advantage of increased ring strain in the reactant, is possible at the much lower temperature of 37 °C.
Naturally occurring compounds such as calicheamicin contain the same 10-membered ring and are found to be cytotoxic. These compounds generate the diradical intermediate described above which can cause single and double stranded DNA cuts. There are novel drugs which attempt to make use of this property, including monoclonal antibodies such as mylotarg.
A biradical mechanism is also proposed for the formation of certain biomolecules found in marine sporolides that have a chlorobenzene unit as part of their structure. In this mechanism a halide salt provides the halogen. A model reaction with the enediyene cyclodeca-1,5-diyn-3-ene, lithium bromide as halogen source and acetic acid as hydrogen source in DMSO at 37 °C supports the theory:
The reaction is found to be first-order in enediyne with the formation of p-benzyne A as the rate-limiting step. The halide ion then donates its two electrons in the formation of a new Br-C bond and radical electron involved is believed to shuttle over a transient C1-C4 bond forming the anion intermediate B. The anion is a powerful base, stripping protons even from DMSO to final product. The dibromide or dihydrogen product (tetralin) never form.
In 2015 IBM scientists demonstrated that a reversible Masamune-Bergman cyclisation of diyne can be induced by a tip of an atomic force microscope (AFM). They also recorded images of individual diyne molecules during this process. When learning about this direct experimental demonstration Bergman commented, "When we first reported this reaction I had no idea that it would be biologically relevant, or that the reaction could someday be visualized at the molecular level.
References
External links
Bergman Cycloaromatization Powerpoint Whitney M. Erwin 2002
Rearrangement reactions
Carbon-carbon bond forming reactions
Name reactions
Enediynes | Bergman cyclization | Chemistry | 706 |
21,958,391 | https://en.wikipedia.org/wiki/Journal%20of%20Materials%20Science | The Journal of Materials Science is a weekly peer-reviewed scientific journal covering all aspects of materials science. It was established in 1966 by Robert W. Cahn and is published by Springer Science+Business Media. The journal incorporated Journal of Materials Science Letters in 2003 and Interface Science in 2004. The Editor-in-Chief is C. Barry Carter (University of Connecticut).
In 2012, the journal announced an annual "Cahn Prize" for best paper published in the journal, in honor of its founding editor.
In 2021, the journal announced a similar annual "Bonfield Prize" for best review paper published in the journal, in honor of a former Editor-in-Chief, William Bonfield. There are two more specialized sister journals, Journal of Materials Science: Materials in Medicine and Journal of Materials Science: Materials in Electronics.
Abstracting and indexing
The journal is abstracted and indexed in:
According to the Journal Citation Reports, the journal has a 2020 impact factor of 4.220, ranking it 82nd out of 293 journals in the category "Materials Science, Multidisciplinary".
See also
Journal of Materials Science Letters
References
External links
English-language journals
Academic journals established in 1966
Springer Science+Business Media academic journals
Materials science journals
Biweekly journals | Journal of Materials Science | Materials_science,Engineering | 256 |
23,588,720 | https://en.wikipedia.org/wiki/Aarhus%20Protocol%20on%20Persistent%20Organic%20Pollutants | The Aarhus Protocol on Persistent Organic Pollutants, a 1998 protocol on persistent organic pollutants (POPs), is an addition to the 1979 Geneva Convention on Long-Range Transboundary Air Pollution (LRTAP). The Protocol seeks "to control, reduce or eliminate discharge, emissions and losses of persistent organic pollutants" in Europe, some former Soviet Union countries, and the United States, in order to reduce their transboundary fluxes so as to protect human health and the environment from adverse effects.
Authors and promoters of the Protocol were the United Nations Economic Commission for Europe (UNECE), which at the time housed 53 different country members and alliance. The protocol was amended on 18 December 2009: the Amendments to the Text and to Annexes I, II, III, IV, VI and VIII to the 1998 Protocol on Persistent Organic Pollutants came into force on 20/01/2022 and the Amendments to Annexes I and II to the 1998 Protocol on Persistent Organic Pollutants came into force on 26/02/2023.
As of May 2013, the protocol has been ratified by 31 states and the European Union.
In the United States, the protocol is an executive agreement that does not require Senate approval. However, legislation is needed to resolve inconsistencies between provisions of the protocol and existing U.S. laws (specifically the Toxic Substances Control Act and the Federal Insecticide, Fungicide, and Rodenticide Act).
Substances
The following substances are contained in the CLRTAP POPs Protocol. The document focuses on a list of 16 substances that have been singled out according to agreed risk criteria (comprising eleven pesticides, two industrial chemicals and three by-products/contaminants). The Protocol assigned the arrangements for proper disposal of waste products deemed banned and limited, including medical supplies.
See also
Convention on Long-Range Transboundary Air Pollution
Stockholm Convention on Persistent Organic Pollutants
Environmental agreements
International POPs Elimination Network (IPEN)
References
External links
Original text
Overview - United Nations Economic Commission for Europe webpage
Amended text (April 2010)
Signatures and ratifications
Biodegradable waste management
Waste treaties
Treaties concluded in 1998
1998 in Denmark
Treaties of Austria
Treaties of Belgium
Treaties of Bulgaria
Treaties of Canada
Treaties of Croatia
Treaties of Cyprus
Treaties of the Czech Republic
Treaties of Denmark
Treaties of Estonia
Treaties of Finland
Treaties of France
Treaties of Germany
Treaties of Hungary
Treaties of Iceland
Treaties of Italy
Treaties of Latvia
Treaties of Liechtenstein
Treaties of Lithuania
Treaties of Luxembourg
Treaties of Montenegro
Treaties of the Netherlands
Treaties of Norway
Treaties of Moldova
Treaties of Romania
Treaties of Serbia
Treaties of Slovakia
Treaties of Slovenia
Treaties of Spain
Treaties of Sweden
Treaties of Switzerland
Treaties of the United Kingdom
Treaties entered into by the European Union
Convention on Long-Range Transboundary Air Pollution
Treaties extended to the Faroe Islands
Treaties extended to Greenland
United Nations Economic Commission for Europe treaties
Environmental treaties
Air pollution
Treaties entered into force in 2003
2003 in the environment
Treaties of North Macedonia | Aarhus Protocol on Persistent Organic Pollutants | Chemistry | 594 |
2,611,971 | https://en.wikipedia.org/wiki/Bioinformatic%20Harvester | The Bioinformatic Harvester was a bioinformatic meta search engine created by the European Molecular Biology Laboratory and subsequently hosted and further developed by KIT Karlsruhe Institute of Technology for genes and protein-associated information. Harvester currently works for human, mouse, rat, zebrafish, drosophila and arabidopsis thaliana based information. Harvester cross-links >50 popular bioinformatic resources and allows cross searches. Harvester serves tens of thousands of pages every day to scientists and physicians. Since 2014 the service is down.
How Harvester works
Harvester collects information from protein and gene databases along with information from so called "prediction servers." Prediction server e.g. provide online sequence analysis for a single protein. Harvesters search index is based on the IPI and UniProt protein information collection. The collections consists of:
~72.000 human, ~57.000 mouse, ~41.000 rat, ~51.000 zebrafish, ~35.000 arabidopsis protein pages, which cross-link ~50 major bioinformatic resources.
Harvester crosslinks several types of information
Text based information
From the following databases:
UniProt, one of the largest protein databases
SOURCE, convenient gene information overview
Simple Modular Architecture Research Tool (SMART)
SOSUI, predicts transmembrane domains
PSORT, predicts protein localisation
HomoloGene, compares proteins from different species
gfp-cdna, protein localisation with fluorescence microscopy
International Protein Index (IPI)
Databases rich in graphical elements
These databases are not collected, but are crosslinked, being displayed via iframes. An iframe is a window within an HTML page for an embedded view of and interactive access to the linked database. Several such iframes are combined on a single Harvester protein page. This allows simultaneous, convenient comparison of information from several databases.
NCBI-BLAST, an algorithm for comparing biological sequences from the NCBI
Ensembl, automatic gene annotation by the EMBL-EBI and Sanger Institute
FlyBase is a database of model organism Drosophila melanogaster
GoPubMed is a knowledge-based search engine for biomedical texts
iHOP, information hyperlinked over proteins via gene/protein synonyms
Mendelian Inheritance in Man project catalogues all the known diseases
RZPD, German resources Center for genome research in Berlin/Heidelberg
STRING, Search Tool for the Retrieval of Interacting Genes/Proteins, developed by EMBL, SIB and UZH
Zebrafish Information Network
LOCATE subcellular localisation database (mouse)
Access from external application
Genome browser, working draft assemblies for genomes UCSC
Google Scholar
Mitocheck
PolyMeta, meta search engine for Google, Yahoo, MSN, Ask, Exalead, AllTheWeb, GigaBlast
What one can find
Harvester allows a combination of different search terms and single words.
Search Examples:
Gene-name: "golga3"
Gene-alias: "ADAP-S ADAS ADHAPS ADPS" (one gene name is sufficient)
Gene-Ontologies: "Enzyme linked receptor protein signaling pathway"
Unigene-Cluster: "Hs.449360"
Go-annotation: "intra-Golgi transport"
Molecular function: "protein kinase binding"
Protein: "Q9NPD3"
Protein domain: "SH2 sar"
Protein Localisation: "endoplasmic reticulum"
Chromosome: "2q31"
Disease relevant: use the word "diseaselink"
Combinations: "golgi diseaselink" (finds all golgi proteins associated with a disease)
mRNA: "AL136897"
Word: "Cancer"
Comment: "highly expressed in heart"
Author: "Merkel, Schmidt"
Publication or project: "cDNA sequencing project"
See also
List of academic databases and search engines
Biological databases
Entrez
European Bioinformatics Institute
Human Protein Reference Database
Metadata
Sequence profiling tool
Literature
Notes and references
External links
Bioinformatic Harvester V at KIT Karlsruhe Institute of Technology
Bioinformatics software
Biological databases
Biology websites
Internet search engines
Science and technology in Cambridgeshire
South Cambridgeshire District | Bioinformatic Harvester | Biology | 858 |
14,863,422 | https://en.wikipedia.org/wiki/TRISPHAT | TRISPHAT (full name tris(tetrachlorocatecholato)phosphate(1−)) is an inorganic anion with the formula often prepared as the tributylammonium () or tetrabutylammonium ( salt. The anion features phosphorus(V) bonded to three tetrachlorocatecholate () ligands. This anion can be resolved into the axially chiral enantiomers, which are optically stable (the picture shows the Δ enantiomer).
The TRISPHAT anion has been used as a chiral shift reagent for cations. It improves the resolution of 1H NMR spectra by forming diastereomeric ion pairs.
Preparation
The anion is prepared by treatment of phosphorus pentachloride with tetrachlorocatechol followed by a tertiary amine gives the anion:
PCl5 + 3 C6Cl4(OH)2 → H[P(O2C6Cl4)3] + 5 HCl
H[P(O2C6Cl4)3] + Bu3N → Bu3NH+ [P(O2C6Cl4)3]−
Using a chiral amine, the anion can be readily resolved.
References
Organophosphates
Anions
Chloroarenes
Catechols
Phosphates
Nuclear magnetic resonance | TRISPHAT | Physics,Chemistry | 288 |
57,429,688 | https://en.wikipedia.org/wiki/High-voltage%20transformer%20fire%20barriers | High-voltage transformer fire barriers, also known as transformer firewalls, transformer ballistic firewalls, or transformer blast walls, are outdoor countermeasures against a fire or explosion involving a single transformer from damaging adjacent transformers. These barriers compartmentalize transformer fires and explosions involving combustible transformer oil.
High-voltage transformer fire barriers are typically located in electrical substations, but may also be attached to buildings, such as valve halls or manufacturing plants with large electrical distribution systems, such as pulp and paper mills. Outdoor transformer fire barriers that are attached at least on one side to a building are referred to as wing walls.
Voluntary recommendations by NFPA 850
The primary North American document that deals with outdoor high-voltage transformer fire barriers is NFPA 850. NFPA 850 outlines that outdoor oil-insulated transformers should be separated from adjacent structures and from each other by firewalls, spatial separation, or other approved means for the purpose of limiting the damage and potential spread of fire from a transformer failure.
Automatic fire suppression systems
Instead of a passive barrier, fire protection water spray systems are sometimes used to cool a transformer to prevent damage if exposed to radiation heat transfer from a fire involving oil released from another transformer that has failed.
Transformer Fast Depressurization Systems (FDS)
Mechanical systems designed to quickly depressurize the transformer oil tank after the occurrence of an electrical fault can minimize the chance that a transformer tank will rupture given a minor fault, but are not effective on major internal faults.
Alternatives to mineral-based transformer oil
Transformer oil is available in with sufficiently low combustibility that a fire will not continue after an internal electrical fault. These fluids include those approved by FM Global. FM Data Sheet 5-4 indicates different levels of protection depending on the type of fluid used. Alternatives include, but are not limited to, esters and silicone oil.
See also
Arc fault
Cascading failure
Electrical power distribution
Fire test
Firewall (construction)
North American Electric Reliability Corporation
Passive fire protection
References
Armour
Electric power conversion
Electric transformers
Energy infrastructure
Explosions
Infrastructure
Passive fire protection
Security engineering | High-voltage transformer fire barriers | Chemistry,Engineering | 443 |
2,821,622 | https://en.wikipedia.org/wiki/Lycoperdon%20perlatum | Lycoperdon perlatum, popularly known as the common puffball, warted puffball, gem-studded puffball or devil's snuff-box, is a species of puffball fungus in the family Agaricaceae. A widespread species with a cosmopolitan distribution, it is a medium-sized puffball with a round fruit body tapering to a wide stalk, and dimensions of wide by tall. It is off-white with a top covered in short spiny bumps or "jewels", which are easily rubbed off to leave a netlike pattern on the surface. When mature it becomes brown, and a hole in the top opens to release spores in a burst when the body is compressed by touch or falling raindrops.
The puffball grows in fields, gardens, and along roadsides, as well as in grassy clearings in woods. It is edible when young and the internal flesh is completely white, although care must be taken to avoid confusion with immature fruit bodies of poisonous Amanita species. L. perlatum can usually be distinguished from other similar puffballs by differences in surface texture. Several chemical compounds have been isolated and identified from the fruit bodies of L. perlatum, including sterol derivatives, volatile compounds that give the puffball its flavor and odor, and the unusual amino acid lycoperdic acid. Extracts of the puffball have antimicrobial and antifungal activities.
Taxonomy
The species was first described in the scientific literature in 1796 by mycologist Christiaan Hendrik Persoon. Synonyms include Lycoperdon gemmatum (as described by August Batsch in 1783); the variety Lycoperdon gemmatum var. perlatum (published by Elias Magnus Fries in 1829); Lycoperdon bonordenii (George Edward Massee, 1887); and Lycoperdon perlatum var. bonordenii (A.C. Perdeck, 1950).
L. perlatum is the type species of the genus Lycoperdon. Molecular analyses suggest a close phylogenetic relationship with L. marginatum.
The specific epithet perlatum is Latin for "widespread". It is commonly known as the common puffball, the gem-studded puffball (or gemmed puffball), the warted puffball, or the devil's snuff-box; Samuel Frederick Gray called it the pearly puff-ball in his 1821 work A Natural Arrangement of British Plants. Because some indigenous peoples believed that the spores caused blindness, the puffball has some local names such as "blindman's bellows" and "no-eyes".
Description
The fruit body ranges in shape from pear-like with a flattened top, to nearly spherical, and reaches dimensions of wide by tall. It has a stem-like base, and is whitish before browning in age. The outer surface of the fruit body (the exoperidium) is covered in short cone-shaped spines that are interspersed with granular warts. The spines, which are whitish, gray, or brown, can be easily rubbed off, and leave reticulate pock marks or scars after they are removed. The base of the puffball is thick. It is initially white, but turns yellow, olive, or brownish in age. The reticulate pattern resulting from the rubbed-off spines is less evident on the base.
In maturity, the exoperidium at the top of the puffball sloughs away, revealing a pre-formed hole (ostiole) in the endoperidium, through which the spores can escape. In young puffballs, the internal contents, the gleba, is white and firm, but turns brown and powdery as the spores mature. The gleba contains minute chambers that are lined with hymenium (the fertile, spore-bearing tissue); the chambers collapse when the spores mature. Mature puffballs release their powdery spores through the ostiole when they are compressed by touch or falling raindrops. A study of the spore release mechanism in L. pyriforme using high-speed schlieren photography determined that raindrops of 1 mm diameter or greater, including rain drips from nearby trees, were sufficient to cause spore discharge. The puffed spores are ejected from the ostiole at a velocity of about 100 cm/second to form a centimeter-tall cloud one-hundredth of a second after impact. A single puff like this can release over a million spores.
The spores are spherical, thick-walled, covered with minute spines, and measure 3.5–4.5 μm in diameter. The capillitia (threadlike filaments in the gleba in which spores are embedded) are yellow-brown to brownish in color, lack septae, and measure 3–7.5 μm in diameter. The basidia (spore-bearing cells) are club-shaped, four-spored, and measure 7–9 by 4–5 μm. The basidia bear four slender sterigmata of unequal length ranging from 5–10 μm long. The surface spines are made of chains of pseudoparenchymatous hyphae (resembling the parenchyma of higher plants), in which the individual hyphal cells are spherical to elliptical in shape, thick-walled (up to 1 μm), and measure 13–40 by 9–35 μm. These hyphae do not have clamp connections.
Similar species
There are several other puffball species with which L. perlatum might be confused. L. nettyanum, found in the Pacific Northwest region of the United States, is covered in granular patches, but these granules adhere more strongly to the surface than those of L. perlatum. L. pyriforme lacks prominent spines on the surface, and grows on rotting wood—although if growing on buried wood, it may appear to be terrestrial. The widely distributed and common L. umbrinum has spines that do not leave scars when rubbed off, a gleba that varies in color from dark brown to purple-brown at maturity, and a purple-tinged base. The small and rare species L. muscorum grows in deep moss. L. peckii can be distinguished from L. pyriforme by the lavender-tinged spines it has when young. L. rimulatum has purplish spores, and an almost completely smooth exoperidium. L. excipuliforme is larger and grayer, and, in mature individuals, the upper portion of its fruit body breaks down completely to release its spores. In the field, L. marginatum is distinguished from L. perlatum by the way in which the spines are shed from the exoperidium in irregular sheets.
Ecology and distribution
A saprobic species, Lycoperdon perlatum grows solitarily, scattered, or in groups or clusters on the ground. It can also grow in fairy rings. Typical habitats include woods, grassy areas, and along roads. It has been reported from Pinus patula plantations in Tamil Nadu, India. The puffball sometimes confuses golfers because of its resemblance to a golf ball when viewed from a distance.
A widespread species with an almost cosmopolitan distribution, it has been reported from Africa (Kenya, Rwanda, Tanzania), Asia (China, Himalayas, Japan, southern India Iran), Australia, Europe, New Zealand, and South America (Brazil). It has been collected from subarctic areas of Greenland, and subalpine regions in Iceland. In North America, where it is considered the most common puffball species, it ranges from Alaska to Mexico, although it is less common in Central America. The species is popular on postage stamps, and has been depicted on stamps from Guinea, Paraguay, Romania, Sierra Leone, and Sweden.
The puffball bioaccumulates heavy metals present in the soil, and can be used as a bioindicator of soil pollution by heavy metals and selenium. In one 1977 study, samples collected from grassy areas near the side of an interstate highway in Connecticut were shown to have high concentrations of cadmium and lead. L. perlatum biomass has been shown experimentally to remove mercury ions from aqueous solutions, and is being investigated for potential use as a low-cost, renewable, biosorptive material in the treatment of water and wastewater containing mercury.
Edibility
Lycoperdon perlatum is considered to be a good edible mushroom when young, when the gleba is still homogeneous and white. They have been referred to as "poor man's sweetbread" due to their texture and flavor. The fruit bodies can be eaten after slicing and frying in batter or egg and breadcrumbs, or used in soups as a substitute for dumplings. As early as 1861, Elias Fries recommended them dried and served with salt, pepper, and oil. The puffballs become inedible as they mature: the gleba becomes yellow-tinged then finally develops into a mass of powdery olive-green spores. L. perlatum is one of several edible species sold in markets in the Mexican states of Puebla and Tlaxcala. The fruit bodies are appealing to animals as well: the northern flying squirrel (Glaucomys sabrinus) includes the puffball in their diet of non-truffle fungi, while the "puffball beetle" Caenocara subglobosum uses the fruit body for shelter and breeding. Nutritional analysis indicates that the puffballs are a good source of protein, carbohydrates, fats, and several micronutrients. The predominant fatty acids in the puffball are linoleic acid (37% of the total fatty acids), oleic acid (24%), palmitic acid (14.5%), and stearic acid (6.4%).
The immature 'buttons' or 'eggs' of deadly Amanita species can be confused with puffballs. This can be avoided by slicing fruit bodies vertically and inspecting them for the internal developing structures of a mushroom, which would indicate the poisonous Amanita. Additionally, amanitas will generally not have "jewels" or a bumpy external surface.
The spores' surfaces have many microscopic spines and can cause severe irritation of the lung (lycoperdonosis) when inhaled. This condition has been reported to afflict dogs that play or run where the puffballs are present.
Chemistry
Several steroid derivatives have been isolated and identified from fruit bodies of L. perlatum, including (S)-23-hydroxylanostrol, ergosterol α-endoperoxide, ergosterol 9,11-dehydroendoperoxide and (23E)-lanosta-8,23-dien-3β,25-diol. The compounds 3-octanone, 1-octen-3-ol, and (Z)-3-octen-1-ol are the predominant components of the volatile chemicals that give the puffball its odor and flavor. Extracts of the puffball contain relatively high levels of antimicrobial activity against laboratory cultures of the human pathogenic bacteria Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, with activity comparable to that of the antibiotic ampicillin. These results corroborate an earlier study that additionally reported antibacterial activity against Salmonella enterica serovar Typhimurium, Streptococcus pyogenes, and Mycobacterium smegmatis. Extracts of the puffball have also been reported to have antifungal activity against Candida albicans, C. tropicalis, Aspergillus fumigatus, Alternaria solani, Botrytis cinerea, and Verticillium dahliae. A 2009 study found L. perlatum puffballs to contain cinnamic acid at a concentration of about 14 milligrams per kilogram of mushroom. The fruit bodies contain the pigment melanin.
The amino acid lycoperdic acid (chemical name 3-(5(S)-carboxy-2-oxotetrahydrofuran-5(S)-yl)-2(S)-alanine) was isolated from the puffball, and reported in a 1978 publication. Based on the structural similarity of the new amino acid with (S)-glutamic acid, (S)-(+)-lycoperdic acid is expected to have antagonistic or agonistic activity for the glutamate receptor in the mammalian central nervous system. Methods to synthesize the compounds were reported in 1992, 1995, and 2002.
References
External links
Lycoperdon
Edible fungi
Puffballs
Fungi described in 1796
Fungi found in fairy rings
Fungi of Asia
Fungi of Australia
Fungi of Central America
Fungi of Europe
Fungi of New Zealand
Fungi of North America
Fungi of Oceania
Fungi of South America
Taxa named by Christiaan Hendrik Persoon
Fungi of Iceland
Fungus species | Lycoperdon perlatum | Biology | 2,722 |
67,068,617 | https://en.wikipedia.org/wiki/Collection%20of%20Internet%20Connection%20Records | , collection of Internet Connection Records is being secretly trialled by two major British ISPs as part of a technical trial for mass surveillance under the Investigatory Powers Act 2016. The Home Office and National Crime Agency are also participating in the trial.
"Internet Connection Records" is a generic term for metadata records of UK Internet users' Internet access patterns. Data collected may include who they are, what sites they connected to and when, and what quantity of data was transferred, but does not include the data content of the transmissions. While the participants have been kept secret, the existence of the trial has been confirmed by the Investigatory Powers Commissioner’s Office.
See also
Mass surveillance in the United Kingdom
NetFlow
Pen register
Traffic analysis
References
Government databases in the United Kingdom
Internet in the United Kingdom
Mass surveillance in the United Kingdom
Surveillance databases
Metadata | Collection of Internet Connection Records | Technology | 167 |
35,516,605 | https://en.wikipedia.org/wiki/Photometeor | In atmospheric optics, a photometeor is a bright object or other optical phenomenon appearing in the Earth's atmosphere when sunlight or moonlight creates a reflection, refraction, diffraction or interference under particular circumstances. The most common examples include halos, rainbows, fogbows, cloud iridescences (or irisation), glories, Bishop's rings, coronas, crepuscular rays, sun dogs, light pillars, mirages, scintillations, and green flashes.
Photometeors are not reported in routine weather observation.
See also
Hydrometeor
Rayleigh scattering
Notes and references
External links
South pole halos - an example of halos and arcs around the south polar sun
Atmospheric optical phenomena
sv:Meteor#Fotometeorer | Photometeor | Physics | 163 |
58,540,648 | https://en.wikipedia.org/wiki/Aspergillus%20europaeus | Aspergillus europaeus (also referred to as A. sauternesii) is a species of fungus in the genus Aspergillus. It is from the Cremei section. The species was first described in 2016. It has been reported to produce sulochrins and bianthrons.
References
europaeus
Fungi described in 2016
Fungus species | Aspergillus europaeus | Biology | 75 |
229,070 | https://en.wikipedia.org/wiki/Brooks%27s%20law | Brooks's law is an observation about software project management that "Adding manpower to a late software project makes it later." It was coined by Fred Brooks in his 1975 book The Mythical Man-Month. According to Brooks, under certain conditions, an incremental person when added to a project makes it take more, not less time.
Explanations
According to Brooks himself, the law is an "outrageous oversimplification", but it captures the general rule. Brooks points to the main factors that explain why it works this way:
It takes some time for the people added to a project to become productive. Brooks calls this the "ramp up" time. Software projects are complex engineering endeavors, and new workers on the project must first become educated about the work that has preceded them; this education requires diverting resources already working on the project, temporarily diminishing their productivity while the new workers are not yet contributing meaningfully. Each new worker also needs to integrate with a team composed of several engineers who must educate the new worker in their area of expertise in the code base, day by day. In addition to reducing the contribution of experienced workers (because of the need to train), new workers may even make negative contributions, for example, if they introduce bugs that move the project further from completion.
Communication overhead increases as the number of people increases. Due to combinatorial explosion, the number of different communication channels increases rapidly with the number of people. Everyone working on the same task needs to keep in sync, so as more people are added they spend more time trying to find out what everyone else is doing.
Adding more people to a highly divisible task, such as cleaning rooms in a hotel, decreases the overall task duration (up to the point where additional workers get in each other's way). However, other tasks including many specialties in software projects are less divisible; Brooks points out this limited divisibility with another example: while it takes one woman nine months to make one baby, "nine women can't make a baby in one month".
Exceptions and possible solutions
There are some key points in Brooks's law that allow exceptions and open the door for possible solutions.
The first point is to note that Brooks's law only applies to projects that are already late. Projects can be brought back into (or kept in) control if people are added earlier in the process. It is also important to determine if the project is really late, or if the schedule was originally overly optimistic. Scheduling mistakes account for a large number of late projects. Correcting the schedule is the best way to have a meaningful and reliable time frame for the project's completion.
The quantity, quality and role of the people added to the project also must be taken into consideration. One simple way to circumvent the law on an overrun project is to add more people than needed, in such a way that the extra capacity compensates the training and communication overhead. Good programmers or specialists can be added with less overhead for training. People can be added to do other tasks related with the project, for example, quality assurance or documentation; given that the task is clear, ramp up time is minimized.
Good segmentation helps by minimizing the communication overhead between team members. Smaller sub-problems are solved by a smaller team, and a top-level team is responsible for systems integration. For this method to work, the segmentation of the problem must be done correctly in the first place; if done incorrectly, this can make the problem worse, not better, by impeding communication between programmers working on parts of the problem which are actually closely coupled, even when the project plan has decreed that they are not.
An example of segmentation are design patterns that simplify the distribution of work, because the entire team can do its part within the framework provided by that pattern. The design pattern defines the rules that the programmers follow, simplifies communication through the use of a standard language, and provides consistency and scalability.
The Bermuda plan, where most developers on a project are removed ("sent to Bermuda") and the remaining are left to complete the software, has been suggested as a way of circumventing Brooks's law.
See also
Death march (project management)
Anti-pattern
Linus's law
List of eponymous laws
List of software development philosophies
Notes
References
Steve McConnell. "Brooks' Law Repealed," IEEE Software, vol. 16, no. 6, pp. 6–8, Nov/Dec, 1999. Also available at the authors website (Brooks's law repealed?).
Pei Hsia, Chih-tung Hsu, David C. Kung. "Brooks's law Revisited: A System Dynamics Approach," compsac, p. 370, Twenty-Third Annual International Computer Software and Applications Conference, 1999.
R. L. Gordon and J. C. Lamb. "A Close Look at Brooks' Law," Datamation, June 977, pp. 81–86.
Brooks law Is Applicable to Many Collaborative People Activities
Adages
Computer architecture statements
Computing culture
Software project management
1975 neologisms
Collaboration
Waste of resources | Brooks's law | Technology | 1,050 |
1,727,460 | https://en.wikipedia.org/wiki/Henrik%20Kacser | Henrik Kacser FRSE (22 September 1918 – 13 March 1995) was a Austro-Hungarian-born biochemist and geneticist who worked in Britain in the 20th century. Kacser's achievements have been recognised by his election to the Royal Society of Edinburgh in 1990, by an honorary doctorate of the University of Bordeaux II in 1993.
Early life
Henrik Kacser was born in Câmpina, Romania, in 1918 to Olga and Soma Kacser, an engineer, both Austro-Hungarian. The family moved to Berlin, where Henrik went to the Tretscher School.
Before World War II, for educational reasons he moved to Belfast, Northern Ireland, where he did his undergraduate (BSc 1940, MSc 1942) and postgraduate work (PhD 1949) at the Queen's University of Belfast. There he studied chemistry, specialising in physical chemistry as a postgraduate student. He went to the University of Edinburgh in 1952 as a Nuffield Fellow under a scheme to introduce physical scientists into biology. This was to become the start of his work as a geneticist/biochemist. He earned the Diploma of Animal Genetics, and in 1955 he was appointed to the rank of Lecturer in the Department of Genetics at the University of Edinburgh.
Areas of research
In most of his research his original training in physical chemistry is quite evident, as he focused mainly on the physical/chemical aspects of biology. Much of his early work includes work on practical chemistry, kinetics of enzyme reactions and very little on genetics. His work
in this early period attracted little attention, with even the most highly cited paper having only 52 citations in 65 years. Between 1957 and 1973 he had only four publications, and it would have been easy to conclude that his career was over. However, that would have been completely wrong.
Kacser's work falls into four distinct categories: 1. building a foundation in physical chemistry; 2. development of metabolic control analysis; 3. consolidation and 4. expansion. Only in the third phase of his career his expertise in genetics came to light when he set out to find experimental models to demonstrate the correctness of his paper on metabolic control analysis.
The control of flux
Kacser's paper with Jim Burns, The control of flux, later thoroughly revised to take account of changes in terminology, was a landmark paper for both authors. It described how the rates of metabolic pathways were affected by changes in the amounts or activities of pathway enzymes (See Metabolic Control Analysis). They showed that the expectation that a metabolic pathway will be controlled by a single pacemaker reaction is a fallacy, and most of the experimental criteria used in the supposed identification of such steps are misleading. Instead, varying amounts of control can be distributed over the enzymes of the pathway, but this is a property of the metabolic system as a whole and cannot be predicted from the characteristics of the enzymes in isolation.
The molecular basis of dominance
The molecular basis of dominance (Kacser & Burns, 1981) is the companion paper to The control of flux and reveals the full meaning of its footnote "the implication of this for the problem of dominance and its evolution will be dealt with in a separate publication". The connection was that if the flux–enzyme relationship is quasi-hyperbolic, and if, for most enzymes, the wild-type diploid level of enzyme activity occurs where the curve is levelling out, then a heterozygote of the wild-type with a null mutant will have half the enzyme activity but will not exhibit a noticeably reduced flux. Therefore, the wild type appears dominant and the mutant recessive because of the system characteristics of a metabolic pathway.
Influential publications
By the mid-1980s the central ideas of metabolic control analysis laid out in this paper were becoming far more widely accepted. Further experimental methods based on the theories laid out in the paper were used to help in the understanding of metabolic regulation and molecular evolution, and to show how metabolic control analysis could be applied to problems in medicine and biotechnology. The paper with Richard Beeby 1984 showed how the idea of evolution by natural selection could be applied in a constructive way to provide models for the evolution of enzyme catalysis.
Other papers include:
Responses of metabolic systems to large changes in enzyme activities and effectors: 1. The linear treatment of unbranched chains (Small & Kacser, 1993a)
Responses of metabolic systems to large changes in enzyme activities and effectors: 2. The linear treatment of branched chains (Small & Kacser, 1993b)
A universal method for achieving increases in metabolite production (Kacser & Acerenza, 1993)
Control analysis of time-dependent metabolic systems (Acerenza, Sauro & Kacser, 1989)
These papers, in collaboration with Rankin Small and Luis Acerenza, have shown that the prospects for achieving large increases in flux by changing the activity of a single enzyme are poor but a coordinated set of changes, designed by their "Universal Method" could make large changes without catastrophic perturbations of the rest of metabolism.
Biochemical interest in the ideas expressed in "The control of flux" started to grow in the 1980s, particularly with its experimental applications in Amsterdam to oxidative phosphorylation, urea synthesis and gluconeogenesis.
At this time, because the theory of Kacser and Burns and the simultaneous but independent work carried out by Reinhart Heinrich and Tom Rapoport in Berlin were compatible, a common terminology and set of symbols was agreed for the new field of Metabolic Control Analysis.
Later life
On retiring from lecturing in 1988 he became a Fellow of the University of Edinburgh. Kacser was an active geneticist/biochemist right up until his death. At the time of his death, Henrik still ran an active laboratory, had two large grants supporting his work and continued to produce original scientific ideas.
He was elected to the Fellowship of The Royal Society of Edinburgh in 1990. His proposers were W. G. Hill, Alan Robertson, Charlotte Auerbach, Geoffrey Beale and Douglas Scott Falconer. In 1993 he received an honorary doctorate (DUniv) from the University of Bordeaux.
He died in Edinburgh on 13 March 1995.
Family
Henrik married twice: firstly in 1947 to Beatrice McConkey (d. 1969); secondly in 1978 to Elaine Daffern.
References
External links
Obituary, Royal Society of Edinburgh
In memory of Henrik Kacser: Special issue of the Journal of Theoretical Biology.
Annotated Bibliography of Henrik Kacser
1918 births
1995 deaths
Alumni of Queen's University Belfast
Systems biologists
Theoretical biologists
People from Câmpina
Alumni of the University of Edinburgh
Academics of the University of Edinburgh
Fellows of the Royal Society of Edinburgh
Scientists from Belfast
Romanian expatriates in Germany
Romanian emigrants to the United Kingdom | Henrik Kacser | Biology | 1,372 |
26,381,184 | https://en.wikipedia.org/wiki/Tween%20%28software%29 | Tween is a Twitter client for Microsoft Windows, written in Visual Basic .NET. It was one of the most popular Twitter clients in Japan, and it was open-source.
Summary
Originally, Tween was developed for heavy users. For this reason, Tween is a Twitter client with various functions. There are web mode and API mode, and users can switch between modes. Web mode allows users to avoid API limit's operation.
History
The first beta version was released at Hatena Diary on Nov. 21, 2007. Originally web mode was an only way to get data, then API mode was implemented. 0.7.7.7 was released on Oct. 2, 2009, and API mode was set as default. 1.2.0.0 or later became Proprietary software.
References
External links
SourceForge Project Page
Tween Wiki
Twitter services and applications
Social software
Free application software
Formerly open-source or free software | Tween (software) | Technology | 194 |
31,142,766 | https://en.wikipedia.org/wiki/Victimless%20Leather | Victimless Leather (2004) is an art piece that represents a leather jacket without killing any animals. It is a prototype of a stitch-less jacket, grown from cell cultures into a layer of tissue supported by a coat shaped polymer layer. "Victimless Leather" was created as a sub-project of the Tissue Culture & Art Project, (also part of SymbioticA) from the University of Western Australia and showcased at the Museum of Modern Art in New York. The artwork, a miniature jacket made from living mouse stem cells in an incubator, was designed to challenge perceptions of life and human responsibility toward manipulated living systems. This artistic grown garment is intended to confront people with the moral implications of wearing parts of dead animals for protective and aesthetic reasons and confronts notions of relationships with manipulated living systems. However, due to rapid cell growth, the exhibit was eventually "killed" by cutting off its nutrients, aligning with the creators' intent to remind viewers of the responsibility towards manipulated life.
Tissue Culture & Art Project
The SymbioticA website explains what it is, "an artistic laboratory dedicated to the research, learning, critique and hands-on engagement with the life sciences.". The artists work with tissue, constructing and growing complex organisms that can live outside the body, making the new objects semi-living. Their projects are meant to question life, identity and the relationship between humans and other living beings and environments. They are also interested in the ethics around partial life and the possibilities around this type of technology in the future.
Other projects
These are some of the sub-projects that are also part of the TC&A project, in addition to Victimless Leather:
NoArk – NoArk is a collection of cells and tissue from many different organisms, growing together inside a "vessel", a reference to Noah's Ark. The project website states that NoArk is "a tangible as well as symbolic ‘craft’ for observing and understanding a biology that combines the familiar with the other".
Worry Dolls – Seven modern versions of the Guatemalan Worry doll were hand-crafted of degradable polymers and surgical sutures and seeded with skin, muscle and bone tissue. The tissue was then allowed to grow inside a bioreactor, replacing the polymers as it degrades, thus creating seven semi-living dolls.
Disembodied Cuisine – Along with Victimless Leather, this is part of the "Victimless Utopia". The idea for this project was to take cells from a frog and grow them into something possible to eat, displaying it next to the still living frog the food came from. This problematizes the whole meat industry – how we kill animals to eat them. Growing tissue outside of the body of the animal is a way to "make" meat while the animal stays healthy and living.
Extra Ear – ¼ Scale – Using human tissue, a quarter-scale replica of artist Stelarc's ear was grown. The project wanted to confront the cultural perceptions of life now that we are able to manipulate living systems, and also discuss the notions of the wholeness of the body.
The Pig Wings Project – This project bases its ideas on xenotransplantation and genetically modifying pigs so their organs can be transplanted to humans. The artists used tissue engineering and stem cell technologies to grow pig bone tissue, forming three different sets of wings. One set shaped as bat wings ("evil"), one as bird wings ("good") and one as pterosaurs wings ("neutral").
The Idea
An aim for the "Victimless Leather" project is to explore and provoke scientific truths, using conceptual art projects to encourage better understanding of cultural ideas around scientific knowledge. The project website point out how clothing has always been used to protect the fragile skin of humans, but lately have evolved into a fabricated object used as a tool to show one's identity. Based on this, clothing can be explored as a tangible example of the relationship between humans and others, and how humans treat others. As the artists put it: "This particular project will deconstruct our cultural meaning of clothes as a second skin by materialising it and displaying it as an art object."
The intention to grow artificial leather without killing an animal is meant as a contribution to a cultural discussion between art, science and society. Making this jacket presents a possibility of wearing leather that is not part of a dead animal. The projects are presented in Workshops and exhibitions throughout the world to address ethical questions related to bioscience and technology. The artists want the project to be seen in this cultural context, not a commercial one. Their intention is not to create a consumer product, but to offer a starting point for the cultural discussion points mentioned above. As with most of the TC&A projects the artists are concerned with the relationship between humans and other living systems, both natural and scientific made or manipulated.
The Victimless Leather project
Growing the jacket
The artists wanted to make a leather-like material using living tissue, and ended up making it in the shape of a stitchless jacket. The artists based the jacket on a biodegradable polymer, coated it with 3T3 mouse cells to form connective tissue and topped it up with human bone cells in order to create a stronger skin layer.
To create the victimless leather, the team needed an artificial environment where semi-living entities are grown, so it is grown inside a bioreactor that acts as a surrogate body. The bioreactor used in this project was custom made, based on an organ perfusion pump designed by Alexis Carrel and Charles Lindbergh. It has an automatic dripping system which feeds the cells. The artists assumed that when the polymer degraded, an integrated jacket would appear. The resulting jacket was tiny, about 2 inches high and 1,4 inches wide and would just fit a mouse.
To idealize the "victimless" of the jacket, immortalized cell lines or cells that divide and multiply forever once they are removed from an animal or human host forming a renewable resource, have been used in the project. The 3T3 mouse cells all come from a mouse who lived in the 1970s.
Research and development
The research and development of “Victimless Leather” has been conducted in SymbioticA: the Art and Science Collaborative Research Laboratory, School of Anatomy and Human Biology at the University of Western Australia and in consultation with Professor Arunasalam Dharmarajan from the School of Anatomy and Human Biology as well as Verigen, a Perth-based company that specializes in tissue engineered cartilage for clinical applications. Western Australia state made the investment in the project through ArtsWa in Association with the Lotteries Commission.
Exhibitions
From a list of selected TC&A exhibitions.
Killing the Jacket
The victimless leather was featured in the exhibition “Design and the Elastic Mind” at The Museum of Modern Art in New York City, United States. February 24 – May 12, 2008 The project was scheduled to grow continuously until May 12 when the exhibition ended. There were some problems though, when the leather started expanding too quickly, clogging tubes inside the bioreactor. The exhibition leader therefore decided to unplug the project before the end of the exhibition – in a way, killing it.
Response
Because the artificial leather is made semi-living, the project might be seen as speculative and provocative to some people – questioning whether it is better to kill semi-living beings rather than living beings. "One of the most common and somewhat surprising comments we heard was that people were disturbed by our ethics of using living cells to grow living fabric, while the use of leather obtained from animals seems to be accepted without any concern for the well-being of the animals from which the skin has been removed." artist Ionat Zurr uttered after showing the jacket to the public on "The Space Between" exhibition in Australia.
Artists
Oron Catts
Oron Catts was born in Helsinki, Finland in 1967, and is currently residing in Perth, Australia where he has been employed at the University of Western Australia since 1996. He works as an artistic director of SymbioticA, which he is also co-founder of. He is founder of the Tissue Culture & Art Project. From 2000–2001 he was a Research Fellow at the Tissue Engineering and Organ Fabrication Laboratory at Harvard Medical School. He has also worked with numerous other bio-medical laboratories in several different countries.
Ionat Zurr
Ionat Zurr was born in London, UK in 1970, and is currently residing in Perth, Australia. Since 1996 she has been employed at the University of Western Australia, where she also did her PhD titled "Growing Semi-Living Art" under the Faculty of Architecture, Landscape and Visual Arts . Zurr specialises in video production and biological and digital imaging. She works as an assistant professor and academic coordinator at SymbioticA and is co-founder of the Tissue Culture & Art Project. From 2000–2001 she was a research fellow at the Tissue Engineering and Organ Fabrication Laboratory at Harvard Medical School.
Related work and ideas
The project also focuses on human consumption, highlighting that there are victims on every level of it, and that the boundaries between harm and benefit often are blurred. The French actress Brigitte Bardot strongly opposed hunting of animals for vanity and the commercial purpose of the skin. From an indigenous point of view, the context must be seen different. An Inuit hunts the seal and uses the whole body of the animal as a basic resource for his survival.
Similar to ethics like this, is the interest for artificial meat production due to reactions against the livestock sector because of health and environmental problems. A 2006 UN Food and Agriculture Organization FAO report pointed out the livestock sector as one of the most significant contributors to the most serious environmental problems like soil degradation and water pollution. And because of methane, it spews out more greenhouse gases into the atmosphere than transportation.
See also
SymbioticA
BioArt
In vitro meat
Life sciences
Cell biology
PETA
References
BioArt
BioArtists
International artist groups and collectives
Visual arts genres
Cell biology
Animal rights
Artificial leather | Victimless Leather | Chemistry,Biology | 2,045 |
318,648 | https://en.wikipedia.org/wiki/Musica%20universalis | The musica universalis (literally universal music), also called music of the spheres or harmony of the spheres, is a philosophical concept that regards proportions in the movements of celestial bodies—the Sun, Moon, and planets—as a form of music. The theory, originating in ancient Greece, was a tenet of Pythagoreanism, and was later developed by 16th-century astronomer Johannes Kepler. Kepler did not believe this "music" to be audible, but felt that it could nevertheless be heard by the soul. The idea continued to appeal to scholars until the end of the Renaissance, influencing many schools of thought, including humanism.
History
The concept of the "music of the spheres" incorporates the metaphysical principle that mathematical relationships express qualities or "tones" of energy that manifests in numbers, visual angles, shapes and sounds—all connected within a pattern of proportion. Pythagoras first identified that the pitch of a musical note is an inverse proportion to the length of the string that produces it, and that intervals between harmonious sound frequencies form simple numerical ratios. Pythagoras proposed that the Sun, Moon and planets all emit their own unique hum based on their orbital revolution, and that the quality of life on Earth reflects the tenor of celestial sounds which are physically imperceptible to the human ear. Subsequently, Plato described astronomy and music as "twinned" studies of sensual recognition: astronomy for the eyes, music for the ears, and both requiring knowledge of numerical proportions.
Aristotle characterized the theory as follows:
Aristotle rejected the idea, however, as incompatible with his own cosmological model, and on the grounds that "excessive noises ... shatter the solid bodies even of inanimate things", and therefore any sounds made by the planets would necessarily exert a tremendous physical force upon the body.
Boethius, in his influential work De Musica, described three categories of music:
musica mundana (sometimes referred to as musica universalis)
musica humana (the internal music of the human body)
musica quae in quibusdam constituta est instrumentis (sounds made by singers and instrumentalists)
Boethius believed that musica mundana could only be discovered through the intellect, but that the order found within it was the same as that found in audible music, and that both reflect the beauty of God.
Harmonices Mundi
Musica universalis—which had existed as a metaphysical concept since the time of the Greeks—was often taught in quadrivium, and this intriguing connection between music and astronomy stimulated the imagination of Johannes Kepler as he devoted much of his time after publishing the Mysterium Cosmographicum (Mystery of the Cosmos), looking over tables and trying to fit the data to what he believed to be the true nature of the cosmos as it relates to musical sound. In 1619, Kepler published Harmonices Mundi (literally Harmonies of the World), expanding on the concepts he introduced in Mysterium and positing that musical intervals and harmonies describe the motions of the six known planets of the time. He believed that this harmony—while inaudible—could be heard by the soul, and that it gave a "very agreeable feeling of bliss, afforded him by this music in the imitation of God." In Harmonices, Kepler—who took issue with Pythagorean observations—laid out an argument for a Christian-centric creator who had made an explicit connection between geometry, astronomy, and music, and that the planets were arranged intelligently.
Harmonices is split into five books, or chapters. The first and second books give a brief discussion on regular polyhedra and their congruences, reiterating the idea he introduced in Mysterium that the five regular solids known about since antiquity define the orbits of the planets and their distances from the sun. Book three focuses on defining musical harmonies, including consonance and dissonance, intervals (including the problems of just tuning), their relations to string length which was a discovery made by Pythagoras, and what makes music pleasurable to listen to in his opinion. In the fourth book, Kepler presents a metaphysical basis for this system, along with arguments as to why the harmony of the worlds appeals to the intellectual soul in the same manner that the harmony of music appeals to the human soul. Here, he also uses the naturalness of this harmony as an argument for heliocentrism. In book five, Kepler describes in detail the orbital motion of the planets and how this motion nearly perfectly matches musical harmonies. Finally, after a discussion on astrology in book five, Kepler ends Harmonices by describing his third law, which states that—for any planet—the cube of the semi-major axis of its elliptical orbit is proportional to the square of its orbital period.
In the final book of Harmonices, Kepler explains how the ratio of the maximum and minimum angular speeds of each planet (i.e., its speeds at the perihelion and aphelion) is very nearly equivalent to a consonant musical interval. Furthermore, the ratios between these extreme speeds of the planets compared against each other create even more mathematical harmonies. These speeds explain the eccentricity of the orbits of the planets in a natural way that appealed to Kepler's religious beliefs in a heavenly creator.
While Kepler did believe that the harmony of the worlds was inaudible, he related the motions of the planets to musical concepts in book four of Harmonices. He makes an analogy between comparing the extreme speeds of one planet and the extreme speeds of multiple planets with the difference between monophonic and polyphonic music. Because planets with larger eccentricities have a greater variation in speed they produce more "notes." Earth's maximum and minimum speeds, for example, are in a ratio of roughly 16 to 15, or that of a semitone, whereas Venus' orbit is nearly circular, and therefore only produces a singular note. Mercury, which has the largest eccentricity, has the largest interval, a minor tenth, or a ratio of 12 to 5. This range, as well as the relative speeds between the planets, led Kepler to conclude that the Solar System was composed of two basses (Saturn and Jupiter), a tenor (Mars), two altos (Venus and Earth), and a soprano (Mercury), which had sung in "perfect concord," at the beginning of time, and could potentially arrange themselves to do so again. He was certain of the link between musical harmonies and the harmonies of the heavens and believed that "man, the imitator of the Creator," had emulated the polyphony of the heavens so as to enjoy "the continuous duration of the time of the world in a fraction of an hour."
Kepler was so convinced of a creator that he was convinced of the existence of this harmony despite a number of inaccuracies present in Harmonices. Many of the ratios differed by an error greater than simple measurement error from the true value for the interval, and the ratio between Mars' and Jupiter's angular velocities does not create a consonant interval, though every other combination of planets does. Kepler brushed aside this problem by making the argument, with the math to support it, that because these elliptical paths had to fit into the regular solids described in Mysterium the values for both the dimensions of the solids and the angular speeds would have to differ from the ideal values to compensate. This change also had the benefit of helping Kepler retroactively explain why the regular solids encompassing each planet were slightly imperfect. Philosophers posited that the Creator liked variation in the celestial music.
Kepler's books are well-represented in the Library of Sir Thomas Browne, who also expressed a belief in the music of the spheres:
For there is a musicke where-ever there is a harmony, order or proportion; and thus farre we may maintain the musick of the spheres; for those well ordered motions, and regular paces, though they give no sound unto the eare, yet to the understanding they strike a note most full of harmony. Whatsoever is harmonically composed, delights in harmony.
Orbital resonance
In celestial mechanics, orbital resonance occurs when orbiting bodies exert regular, periodic gravitational influence on each other, usually because their orbital periods are related by a ratio of small integers. This has been referred to as a "modern take" on the theory of musica universalis. This idea has been further explored in a musical animation, created by an artist at the European Southern Observatory, of the planetary system TOI-178, which has five planets locked in a chain of orbital resonances.
Cultural influence
William Shakespeare makes reference to the music of the spheres in The Merchant of Venice:
In the 1910s, Danish composer Rued Langgaard composed a pioneering orchestral work titled Music of the Spheres.
Paul Hindemith also made use of the concept in his 1957 opera, Die Harmonie der Welt ("The Harmony of the World"), based upon the life of Johannes Kepler.
A number of other modern compositions have been inspired by the concept of musica universalis. Among these are Harmony of the Spheres by Neil Ardley, live-only track ''La musique des sphères'' by Magma/VanderTop, Music of the Spheres by Mike Oldfield, The Earth Sings Mi Fa Mi by The Receiving End of Sirens, Music of the Spheres by Ian Brown, "Cosmogony" by Björk, and the Coldplay album Music of the Spheres.
Music of the Spheres was also the title of a companion piece to the video game Destiny, composed by Martin O'Donnell, Michael Salvatori, and Paul McCartney.
A concert band arrangement by Philip Sparke has also used the name "Music of the Spheres" and is often used as a set test piece, with a notable studio performance recorded by the YBS Band while led by maestro Professor David King.
Reference is made to the music of the spheres in the short story The Horror in the Museum by H. P. Lovecraft.
In the video game Overwatch, the playable character Sigma often claims the universe is singing to him.
During the 2008 BBC Proms Doctor Who segment, a short interactive mini-episode starring David Tennant and written by showrunner Russell T Davies titled Music of the Spheres was played. This sees the Doctor attempting to compose Ode to the Universe, basing his works on the Music of the Spheres. This piece continues the metaphysical theories of the musica universalis by arguing that the audience themselves are part of the composition.
See also
Asteroseismology
Gravitational waves
Plato's Timaeus
This Is My Father's World
Titius–Bode law
Sacred geometry
Shabd
Notes
Sources
Further reading
Martineau, John (2002). A Little Book of Coincidence in the Solar System. Gardener's Books.
External links
"The Music of the Spheres". In Our Time. BBC Radio 4. June 19, 2008.
"The Harmony of the Spheres". AudioCipher. December 31, 2021.
Ancient astronomy
Concepts in aesthetics
Concepts in metaphysics
Concepts in the philosophy of science
Early scientific cosmologies
Esoteric cosmology
Numerology
Philosophy of music
Pythagorean philosophy | Musica universalis | Astronomy,Mathematics | 2,285 |
1,680,145 | https://en.wikipedia.org/wiki/Strain%20%28chemistry%29 | In chemistry, a molecule experiences strain when its chemical structure undergoes some stress which raises its internal energy in comparison to a strain-free reference compound. The internal energy of a molecule consists of all the energy stored within it. A strained molecule has an additional amount of internal energy which an unstrained molecule does not. This extra internal energy, or strain energy, can be likened to a compressed spring. Much like a compressed spring must be held in place to prevent release of its potential energy, a molecule can be held in an energetically unfavorable conformation by the bonds within that molecule. Without the bonds holding the conformation in place, the strain energy would be released.
Summary
Thermodynamics
The equilibrium of two molecular conformations is determined by the difference in Gibbs free energy of the two conformations. From this energy difference, the equilibrium constant for the two conformations can be determined.
If there is a decrease in Gibbs free energy from one state to another, this transformation is spontaneous and the lower energy state is more stable. A highly strained, higher energy molecular conformation will spontaneously convert to the lower energy molecular conformation.
Enthalpy and entropy are related to Gibbs free energy through the equation (at a constant temperature):
Enthalpy is typically the more important thermodynamic function for determining a more stable molecular conformation. While there are different types of strain, the strain energy associated with all of them is due to the weakening of bonds within the molecule. Since enthalpy is usually more important, entropy can often be ignored. This isn't always the case; if the difference in enthalpy is small, entropy can have a larger effect on the equilibrium. For example, n-butane has two possible conformations, anti and gauche. The anti conformation is more stable by 0.9 kcal mol−1. We would expect that butane is roughly 82% anti and 18% gauche at room temperature. However, there are two possible gauche conformations and only one anti conformation. Therefore, entropy makes a contribution of 0.4 kcal in favor of the gauche conformation. We find that the actual conformational distribution of butane is 70% anti and 30% gauche at room temperature.
Determining molecular strain
The standard heat of formation (ΔfH°) of a compound is described as the enthalpy change when the compound is formed from its separated elements. When the heat of formation for a compound is different from either a prediction or a reference compound, this difference can often be attributed to strain. For example, ΔfH° for cyclohexane is -29.9 kcal mol−1 while ΔfH° for methylcyclopentane is -25.5 kcal mol−1. Despite having the same atoms and number of bonds, methylcyclopentane is higher in energy than cyclohexane. This difference in energy can be attributed to the ring strain of a five-membered ring which is absent in cyclohexane. Experimentally, strain energy is often determined using heats of combustion which is typically an easy experiment to perform.
Determining the strain energy within a molecule requires knowledge of the expected internal energy without the strain. There are two ways do this. First, one could compare to a similar compound that lacks strain, such as in the previous methylcyclohexane example. Unfortunately, it can often be difficult to obtain a suitable compound. An alternative is to use Benson group increment theory. As long as suitable group increments are available for the atoms within a compound, a prediction of ΔfH° can be made. If the experimental ΔfH° differs from the predicted ΔfH°, this difference in energy can be attributed to strain energy.
Kinds of strain
Van der Waals strain
Van der Waals strain, or steric strain, occurs when atoms are forced to get closer than their Van der Waals radii allow. Specifically, Van der Waals strain is considered a form of strain where the interacting atoms are at least four bonds away from each other. The amount on steric strain in similar molecules is dependent on the size of the interacting groups; bulky tert-butyl groups take up much more space than methyl groups and often experience greater steric interactions.
The effects of steric strain in the reaction of trialkylamines and trimethylboron were studied by Nobel laureate Herbert C. Brown et al. They found that as the size of the alkyl groups on the amine were increased, the equilibrium constant decreased as well. The shift in equilibrium was attributed to steric strain between the alkyl groups of the amine and the methyl groups on boron.
Syn-pentane strain
There are situations where seemingly identical conformations are not equal in strain energy. Syn-pentane strain is an example of this situation. There are two different ways to put both of the bonds the central in n-pentane into a gauche conformation, one of which is 3 kcal mol−1 higher in energy than the other. When the two methyl-substituted bonds are rotated from anti to gauche in opposite directions, the molecule assumes a cyclopentane-like conformation where the two terminal methyl groups are brought into proximity. If the bonds are rotated in the same direction, this doesn't occur. The steric strain between the two terminal methyl groups accounts for the difference in energy between the two similar, yet very different conformations.
Allylic strain
Allylic strain, or A1,3 strain is closely associated to syn-pentane strain. An example of allylic strain can be seen in the compound 2-pentene. It's possible for the ethyl substituent of the olefin to rotate such that the terminal methyl group is brought near to the vicinal methyl group of the olefin. These types of compounds usually take a more linear conformation to avoid the steric strain between the substituents.
1,3-diaxial strain
1,3-diaxial strain is another form of strain similar to syn-pentane. In this case, the strain occurs due to steric interactions between a substituent of a cyclohexane ring ('α') and gauche interactions between the alpha substituent and both methylene carbons two bonds away from the substituent in question (hence, 1,3-diaxial interactions). When the substituent is axial, it is brought near to an axial gamma hydrogen. The amount of strain is largely dependent on the size of the substituent and can be relieved by forming into the major chair conformation placing the substituent in an equatorial position. The difference in energy between conformations is called the A value and is well known for many different substituents. The A value is a thermodynamic parameter and was originally measured along with other methods using the Gibbs free energy equation and, for example, the Meerwein–Ponndorf–Verley reduction/Oppenauer oxidation equilibrium for the measurement of axial versus equatorial values of cyclohexanone/cyclohexanol (0.7 kcal mol−1).
Torsional strain
Torsional strain is the resistance to bond twisting. In cyclic molecules, it is also called Pitzer strain.
Torsional strain occurs when atoms separated by three bonds are placed in an eclipsed conformation instead of the more stable staggered conformation. The barrier of rotation between staggered conformations of ethane is approximately 2.9 kcal mol−1. It was initially believed that the barrier to rotation was due to steric interactions between vicinal hydrogens, but the Van der Waals radius of hydrogen is too small for this to be the case. Recent research has shown that the staggered conformation may be more stable due to a hyperconjugative effect. Rotation away from the staggered conformation interrupts this stabilizing force.
More complex molecules, such as butane, have more than one possible staggered conformation. The anti conformation of butane is approximately 0.9 kcal mol−1 (3.8 kJ mol−1) more stable than the gauche conformation. Both of these staggered conformations are much more stable than the eclipsed conformations. Instead of a hyperconjugative effect, such as that in ethane, the strain energy in butane is due to both steric interactions between methyl groups and angle strain caused by these interactions.
Ring strain
According to the VSEPR theory of molecular bonding, the preferred geometry of a molecule is that in which both bonding and non-bonding electrons are as far apart as possible. In molecules, it is quite common for these angles to be somewhat compressed or expanded compared to their optimal value. This strain is referred to as angle strain, or Baeyer strain. The simplest examples of angle strain are small cycloalkanes such as cyclopropane and cyclobutane, which are discussed below. Furthermore, there is often eclipsing or Pitzer strain in cyclic systems. These and possible transannular interactions were summarized early by H.C. Brown as internal strain, or I-Strain. Molecular mechanics or force field approaches allow to calculate such strain contributions, which then can be correlated e.g. with reaction rates or equilibria. Many reactions of alicyclic compounds, including equilibria, redox and solvolysis reactions, which all are characterized by transition between sp2 and sp3 state at the reaction center, correlate with corresponding strain energy differences SI (sp2 -sp3). The data reflect mainly the unfavourable vicinal angles in medium rings, as illustrated by the severe increase of ketone reduction rates with increasing SI (Figure 1). Another example is the solvolysis of bridgehead tosylates with steric energy differences between corresponding bromide derivatives (sp3) and the carbenium ion as sp2- model for the transition state. (Figure 2)
In principle, angle strain can occur in acyclic compounds, but the phenomenon is rare.
Small rings
Cyclohexane is considered a benchmark in determining ring strain in cycloalkanes and it is commonly accepted that there is little to no strain energy. In comparison, smaller cycloalkanes are much higher in energy due to increased strain. Cyclopropane is analogous to a triangle and thus has bond angles of 60°, much lower than the preferred 109.5° of an sp3 hybridized carbon. Furthermore, the hydrogens in cyclopropane are eclipsed. Cyclobutane experiences similar strain, with bond angles of approximately 88° (it isn't completely planar) and eclipsed hydrogens. The strain energy of cyclopropane and cyclobutane are 27.5 and 26.3 kcal mol−1, respectively. Cyclopentane experiences much less strain, mainly due to torsional strain from eclipsed hydrogens: its preferred conformations interconvert by a process called pseudorotation.
Ring strain can be considerably higher in bicyclic systems. For example, bicyclobutane, C4H6, is noted for being one of the most strained compounds that is isolatable on a large scale; its strain energy is estimated at 63.9 kcal mol−1 (267 kJ mol−1).
Transannular strain
Medium-sized rings (7–13 carbons) experience more strain energy than cyclohexane, due mostly to deviation from ideal vicinal angles, or Pitzer strain. Molecular mechanics calculations indicate that transannular strain, also known as Prelog strain, does not play an essential role. Transannular reactions however, such as 1,5-shifts in cyclooctane substitution reactions, are well known.
Bicyclic systems
The amount of strain energy in bicyclic systems is commonly the sum of the strain energy in each individual ring. This isn't always the case, as sometimes the fusion of rings induces some extra strain.
Strain in allosteric systems
In synthetic allosteric systems there are typically two or more conformers with stability differences due to strain contributions. Positive cooperativity for example results from increased binding of a substrate A to a conformer C2 which is produced by binding of an effector molecule E. If the conformer C2 has a similar stability as another equilibrating conformer C1 a fit induced by the substrate A will lead to binding of A to C2 also in absence of the effector E. Only if the stability of the conformer C2 is significantly smaller, meaning that in absence of an effector E the population of C2 is much smaller than that of C1, the ratio K2/K1 which measures the efficiency of the allosteric signal will increase. The ratio K2/K1 can be related directly to the strain energy difference between the conformers C1 and C2; if it is small higher concentrations of A will directly bind to C2 and make the effector E inefficient. In addition, the response time of such allosteric switches depends on the strain of the conformer interconversion transitions state.
See also
Strain (materials science)
References
Stereochemistry | Strain (chemistry) | Physics,Chemistry | 2,763 |
19,074,438 | https://en.wikipedia.org/wiki/Plutonium%20borides | Several plutonium borides can be formed by direct combination of plutonium and boron powders in an inert atmosphere at reduced pressure.
PuB was reported to form at 1200 °C with a range of 40–70% boron. It supposedly has a Pu-B bond length of 2.46 Å and the NaCl structure, as do TiB, ZrB and HfB. The existence of PuB was contested later based on several arguments.
PuB2 is formed at 800 °C and has a similar structure to most other metal diborides.
At 1200 °C with 70–85% boron, mixtures of PuB4 and PuB6 are formed, with more of the latter as the temperature increases; PuB4 has the tetragonal structure (same as UB4), and PuB6 has cubic structure, same as all hexaborides (CaB6, LaB6 etc.).
The most remarkable plutonium boride is arguably PuB100. Its existence demonstrates the importance of contamination in boride research because as little as 1% of an impurity is capable of changing its crystal structure.
References
Borides
Plutonium compounds | Plutonium borides | Chemistry | 233 |
13,496,987 | https://en.wikipedia.org/wiki/Nachman%20Aronszajn | Nachman Aronszajn (26 July 1907 – 5 February 1980) was a Polish American mathematician. Aronszajn's main field of study was mathematical analysis, where he systematically developed the concept of reproducing kernel Hilbert space. He also contributed to mathematical logic.
Life
An Ashkenazi Jew, Aronszajn received his Ph.D. from the University of Warsaw, in 1930, in Poland. Stefan Mazurkiewicz was his thesis advisor. He also received a Ph.D. from Paris University, in 1935; this time Maurice Fréchet was his thesis advisor. He joined the Oklahoma State University faculty, but moved to the University of Kansas in 1951 with his colleague Ainsley Diamond after Diamond, a Quaker, was fired for refusing to sign a newly instituted loyalty oath. Aronszajn retired in 1977. He was a Summerfield Distinguished Scholar from 1964 to his death.
Work
He introduced, together with Prom Panitchpakdi, injective metric spaces under the name of "hyperconvex metric spaces". Together with Kennan T. Smith, Aronszajn offered proof of the Aronszajn–Smith theorem. Also, the existence of Aronszajn trees was proven by Aronszajn; Aronszajn lines, also named after him, are the lexicographic orderings of Aronszajn trees.
He also made a contribution to the theory of reproducing kernel Hilbert space. The Moore–Aronszajn theorem is named after him.
References
External links
Nachman Aronszajn on Scientific Commons.
Guide to the Nachman Aronszajn Collection – personal papers of Nachman Aronszajn, 1951–1977
1907 births
1980 deaths
American people of Polish-Jewish descent
Mathematical analysts
Polish emigrants to the United States
Warsaw School of Mathematics
20th-century American mathematicians
University of Kansas faculty
Oklahoma State University faculty
University of Warsaw alumni
People from Warsaw
University of Paris alumni | Nachman Aronszajn | Mathematics | 400 |
67,701,648 | https://en.wikipedia.org/wiki/Gibellula%20pulchra | Gibellula pulchra is a species of parasitic fungus found on arachnids. The species Gibellula pulchra is commonly found around the world.
The genus Gibellula was named after Prof. Giuseppe Gibelli. Some researchers have mistaken Gibellula suffulata as Gibellula pulchra though they are different species from the same genus that both prey on arachnids. Specimens of Gibellula pulchra from North America are held in various collections facilities: the Herbarium of the University of Michigan, Herbarium of Cornell University, Mycological Collection of the U.S. Bureau of Plant Industry, Herbarium of the New York Botanical Garden, and Farlow Herbarium.
Habitat
Like other ascomycetes, Gibellula pulchra can be found under stones, bark, leaves, on decaying logs, or in hidden burrows of plant matter on the forest floor. Often Gibellula pulchra is more clearly identified after entering an arachnid, enveloping their host, and growing on their cadavers. Once a spider dies from the Gibellula pulchra pathogenic fungi, G. pulchra produces a large fruiting body out of the cadaver.
Biology
Gibellula is a parasitoid from the Cordycipitaceae family. In order to attach to a host, Gibellula pulchra sends out spores. When an unlucky spider comes in contact with a spore from Gibellula pulchra, the spores germinate on and envelop the spider host. After germinating, Gibellula pulchra penetrates the host body with a yellow coat of mycelium and digests the spider from the inside out, when the spider has died, stiff lavender clavae begin to shoot up out of the spider cadaver. Gibellula pulchra does not digest the exoskeletons of arachnids which is why the shape of the spider is still visible after Gibellula pulchra has enveloped and killed its host. Not long after the spider host dies, the colors of the mycelium and clavae fade to a cream or ashy color.
References
Note sur Gibellula pulchra (Hypocreales), un hyphomycète parasite des araignées
Curtis's botanical magazine
Cordycipitaceae
Parasitic fungi
Fungi described in 1877
Taxa named by Pier Andrea Saccardo
Fungus species | Gibellula pulchra | Biology | 510 |
24,212,112 | https://en.wikipedia.org/wiki/C40H64 | {{DISPLAYTITLE:C40H64}}
The molecular formula C40H64 (molar mass: 544.94 g/mol, exact mass: 544.5008 u) may refer to:
Phytoene
any tetraterpene
Molecular formulas | C40H64 | Physics,Chemistry | 61 |
69,004,500 | https://en.wikipedia.org/wiki/Dana%20G.%20Goski | Dana Grace Goski (born 1967) is a Canadian-born materials scientist, past president (October 2020–October 2021) of The American Ceramic Society (ACerS), and vice president of research & development at Allied Mineral Products, Inc. During her tenure as ACerS president, she extensively supported the mission and activities of the Society's Diversity & Inclusion Subcommittee and the International Ceramic Arts Network (ICAN), the Society's member organization for clay artisans and potters.
Education
Goski was born in Nova Scotia, Canada. She received her early education at Royal Canadian Air Force Base schools and finished high school in the Nova Scotia public school system. After graduation, she studied chemistry at Dalhousie University in Nova Scotia where she received her B.Sc. in 1989 and M.Sc. in 1992 as a joint project with the National Research Council of Canada (NRC) with a focus on colloidal processing and surface chemistry of alumina and zirconia systems. In 1997, she completed her Ph.D. at the Technical University of Nova Scotia and published her thesis Development of an alumina-mullite composite by reaction sintering.
Career
In 1996, Goski moved to Columbus, Ohio, to join Allied Mineral Products, a global producer of monolithic refractory materials, as a senior research engineer and technical consultant. In 2009, she was named director of research and development before becoming vice president of research and development in 2018 at Allied, where she guides research in advanced ceramic composites and refractory materials.
Goski was named a Fellow of The American Ceramic Society in 2015, awarded the St. Louis Section Theodore J. Planje Award in 2019, and the Marquis Award in 2020.
Awards and recognition
Her patented work on monolithic graphitic castable was recognized with the 2015 ACerS Corporate Technical Achievement Award, given to the Allied Mineral Products team in relation to Goski's patent. In 2019, she was recognized with the Theodore J. Planje Award, given for distinguished achievement in the field of refractories, by the St. Louis Section of ACerS.
For her support of leadership priorities, identification of strategic approaches, and ability to rally people together to achieve significant milestones, she was honored with the ACerS Global Ambassador Award (2019). In 2020, Goski was awarded with the John Marquis Memorial Award for her work published in ACerS journals and related to manufacturing in ceramics and glass.
2015 Fellow of The American Ceramic Society
2015 ACerS Corporate Technical Achievement Award
2019 Theodore J. Planje Award
2019 ACerS Global Ambassador Award
2020 John Marquis Memorial Award
2020–2021 President of The American Ceramic Society
2022 First woman designated as a Distinguished Life Member of the Unified International Technical Conference on Refractories (UNITECR)
References
Canadian emigrants to the United States
Dalhousie University alumni
Fellows of the American Ceramic Society
Canadian materials scientists
Living people
Women materials scientists and engineers
Scientists from Nova Scotia
1967 births | Dana G. Goski | Materials_science,Technology | 602 |
633,423 | https://en.wikipedia.org/wiki/Visual%20Molecular%20Dynamics | Visual Molecular Dynamics (VMD) is a molecular modelling and visualization computer program. VMD is developed mainly as a tool to view and analyze the results of molecular dynamics simulations. It also includes tools for working with volumetric data, sequence data, and arbitrary graphics objects. Molecular scenes can be exported to external rendering tools such as POV-Ray, RenderMan, Tachyon, Virtual Reality Modeling Language (VRML), and many others. Users can run their own Tcl and Python scripts within VMD as it includes embedded Tcl and Python interpreters. VMD runs on Unix, Apple Mac macOS, and Microsoft Windows. VMD is available to non-commercial users under a distribution-specific license which permits both use of the program and modification of its source code, at no charge.
History
VMD has been developed under the aegis of principal investigator Klaus Schulten in the Theoretical and Computational Biophysics group at the Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana–Champaign. A precursor program, called VRChem, was developed in 1992 by Mike Krogh, William Humphrey, and Rick Kufrin. The initial version of VMD was written by William Humphrey, Andrew Dalke, Ken Hamer, Jon Leech, and James Phillips. It was released in 1995. The earliest versions of VMD were developed for Silicon Graphics workstations and could also run in a cave automatic virtual environment (CAVE) and communicate with a Nanoscale Molecular Dynamics (NAMD) simulation. VMD was further developed by A. Dalke, W. Humphrey, J. Ulrich in 1995–1996, followed by Sergei Izrailev and J. Stone during 1997–1998. In 1998, John Stone became the main VMD developer, porting VMD to many other Unix operating systems and completing the first full-featured OpenGL version. The first version of VMD for the Microsoft Windows platform was released in 1999. In 2001, Justin Gullingsrud, and Paul Grayson, and John Stone added support for haptic feedback devices and further developing the interface between VMD and NAMD for performing interactive molecular dynamics simulations. In subsequent developments, Jordi Cohen, Gullingsrud, and Stone entirely rewrote the graphical user interfaces, added built-in support for display and processing of volumetric data, and the use of OpenGL Shading Language.
Interprocess communication
VMD can communicate with other programs via Tcl/Tk. This communication allows the development of several external plugins that works together with VMD. These plugins increases the set of features and tools of VMD making it one of the most used software in computational chemistry, biology, and biochemistry.
Here is a list of some VMD plugins developed using Tcl/Tk:
Delphi Force — electrostatic force calculation and visualization
Pathways Plugin — identify dominant electron transfer pathways and estimate donor-to-acceptor electronic tunneling
Check Sidechains Plugin — checks and helps select best orientation and protonation state for Asn, Gln, and His side chains
MultiMSMS Plugin — caches MSMS calculations to speedup the animation of a sequence of frames
Interactive Essential Dynamics — Interactive visualization of essential dynamics
Mead Ionize — Improved version of autoionize for highly charged systems
Andriy Anishkin's VMD Scripts — Many useful VMD scripts for visualization and analysis
RMSD Trajectory Tool — Development version of RMSD plugin for trajectories
Clustering Tool — Visualize clusters of conformations of a structure
iTrajComp — interactive Trajectory Comparison tool
Swap — Atomic coordinate swapping for improved RMSD alignment
Intervor — Protein-Protein interface extraction and display
SurfVol — Measure surface area and volume of proteins
vmdICE — Plugin for computing RMSD, RMSF, SASA, and other time-varying quantities
molUP - A VMD plugin to handle QM and ONIOM calculations using the gaussian software
VMD Store - A VMD extensions that helps users to discover, install, and update other VMD plugins.
See also
References
External links
VMD on GPUs
Protein workbench STRAP
Molecular modelling software | Visual Molecular Dynamics | Chemistry | 859 |
6,331,838 | https://en.wikipedia.org/wiki/List%20of%20biodiversity%20databases | This is a list of biodiversity databases. Biodiversity databases store taxonomic information alone or more commonly also other information like distribution (spatial) data and ecological data, which provide information on the biodiversity of a particular area or group of living organisms. They may store specimen-level information, species-level information, information on nomenclature, or any combination of the above. Most are available online.
Specimen-focused databases contain data about individual specimens, as represented by vouchered museum specimens, collections of specimen photographs, data on field-based specimen observations and morphological or genetic data. Species-focused databases contain information summarised at the species-level. Some species-focused databases attempt to compile comprehensive data about particular species (FishBase), while others focus on particular species attributes, such as checklists of species in a given area (FEOW) or the conservation status of species (CITES or IUCN Red List). Nomenclators act as summaries of taxonomic revisions and set a key between specimen-focused and species-focused databases. They do this because taxonomic revisions use specimen data to determine species limits.
See also
Taxonomic database
Biodiversity informatics
Global biodiversity
References
External links
List of species databases at the Catalogue of Life
List of biodiversity databases at Biodiversity Tools
Databases
Biodiversity databases
Biology-related lists
Biodiversity
Lists of websites | List of biodiversity databases | Biology,Environmental_science | 263 |
58,760,489 | https://en.wikipedia.org/wiki/Brandi%20Cossairt | Brandi Michelle Cossairt (born June 29, 1984) is an American chemist specializing in synthetic inorganic and materials chemistry. She is the Lloyd E. and Florence M. West Endowed Professor of Chemistry at University of Washington.
Personal life and education
Brandi Cossairt was born and raised in Miami, Florida. She began working in the laboratory of Anthony J. Hynes at the University of Miami's Rosenstiel School of Marine, Atmospheric, and Earth Science while still in high school. She is a first-generation college graduate, having obtained her B.S. in chemistry from the California Institute of Technology in 2006. During her undergraduate degree, Cossairt worked with Jonas C. Peters on electrocatalytic hydrogen evolution with a cobaloxime complex. Cossairt then pursued a graduate degree in inorganic chemistry at the Massachusetts Institute of Technology, where, under the mentorship of Christopher C. Cummins, she received her PhD in 2010. Her doctoral work focused on the niobium-mediated synthesis of phosphorus-rich molecules, such as AsP3. Her academic career next took her to New York, where she joined Columbia University as a National Institutes of Health NRSA Postdoctoral Fellow with Jonathan S. Owen between 2010 and 2012.
Research
Cossairt moved to Seattle in 2012 to begin her independent research career as an assistant professor in the department of chemistry at the University of Washington. Cossairt leads a synthetic inorganic chemistry research group working primarily in colloidal nanoscience. Cossairt's team works to prepare new molecular precursors, develop new synthetic methodologies, and explore the details of complex reaction mechanisms. In particular, her team has pioneered new synthetic strategies to access indium phosphide quantum dots. InP quantum dots have emerged as a class of phosphors for wide color gamut displays and energy-efficient solid-state lighting applications.
Recognition
2018 National Fresenius Award (American Chemical Society, sponsored by Phi Lambda Upsilon)
2017 Camille Dreyfus Teacher Scholar Award (Camille and Henry Dreyfus Foundation)
2016 NSF CAREER Award
2015 Packard Fellowship for Science and Engineering (David and Lucile Packard Foundation)
2015 Sloan Research Fellowship (Alfred P. Sloan Foundation)
2015 Seattle AWIS Award for Early Career Achievement
Organizations
Associate editor at the ACS journal Inorganic Chemistry.
Co-founder (along with Jillian Dempsey, UNC Chapel Hill) of the Chemistry Women Mentorship Network, a national network of women in chemistry to provide support, encouragement, and mentorship for young women considering continuing their education or pursuing careers in academia.
References
1984 births
Living people
American women chemists
American inorganic chemists
California Institute of Technology alumni
Massachusetts Institute of Technology School of Science alumni
University of Washington faculty
American women academics
21st-century American women | Brandi Cossairt | Chemistry | 570 |
171,952 | https://en.wikipedia.org/wiki/Gabriela%20Mistral | Lucila Godoy Alcayaga (; 7 April 1889 – 10 January 1957), known by her pseudonym Gabriela Mistral (), was a Chilean poet-diplomat, educator, and Catholic. She was a member of the Secular Franciscan Order or Third Franciscan order. She was the first Latin American author to receive a Nobel Prize in Literature in 1945, "for her lyric poetry which, inspired by powerful emotions, has made her name a symbol of the idealistic aspirations of the entire Latin American world". Some central themes in her poems are nature, betrayal, love, a mother's love, sorrow and recovery, travel, and Latin American identity as formed from a mixture of Native American and European influences. Her image is featured on the 5,000 Chilean peso banknote.
Early life
Mistral was born in Vicuña, Chile, but grew up in Montegrande, an Andean village where she attended a primary school taught by her older sister, Emelina Molina. Despite the financial problems caused by Emelina later on, Mistral held great respect for her. Her father, Juan Gerónimo Godoy Villanueva, was also a schoolteacher but left the family when she was three years old and died alone and estranged in 1911. Poverty was a constant presence in her early life. At the age of fifteen, she supported herself and her mother, Petronila Alcayaga, a seamstress, by working as a teacher's aide in Compañía Baja, a seaside town near La Serena, Chile.
In 1904, Mistral published some early poems, including Ensoñaciones ("Dreams"), Carta Íntima ("Intimate Letter"), and Junto al Mar ("By the Sea"), in the local newspapers El Coquimbo: Diario Radical and La Voz de Elqui, using different pseudonyms and variations of her name.
In 1906, Mistral met Romelio Ureta, a railway worker and her first love, who tragically took his own life in 1909. Shortly after, her second love married someone else. These heartbreaks were reflected in her early poetry and gained recognition with her first published literary work in 1914, Sonetos de la muerte ("Sonnets on Death"). To protect her job as a teacher, she used a pen name, fearing the consequences of revealing her true identity. Mistral won first prize in the national literary contest Juegos Florales held in Santiago, the capital of Chile. Exploring themes of death and life more broadly than previous Latin American poets, she expanded her poetic horizons. While Mistral had passionate friendships with both men and women, which influenced her writing, she kept her emotional life private.
Since June 1908, Mistral had been using the pen name Gabriela Mistral for most of her writing. After winning the Juegos Florales, she rarely used her given name, Lucila Godoy, for her publications. She constructed her pseudonym from the names of two of her favorite poets, Gabriele D'Annunzio and Frédéric Mistral, or, according to another account, as a combination of the Archangel Gabriel and the mistral wind of Provence.
In 1922, Mistral published her debut book, Desolación ("Desolation"), with assistance from Federico de Onis, the Director of the Hispanic Institute of New York. The collection of poems explored themes such as motherhood, religion, nature, morality, and love for children. Her personal sorrows were reflected in the poems, solidifying her international reputation. Departing from the modernist trends in Latin America, Mistral's work was hailed by critics as straightforward yet simplistic. Two years later, in 1924, she released her second book, Ternura ("Tenderness").
Career as an educator
During her adolescence, the scarcity of trained teachers, especially in rural areas, allowed anyone willing to work to find employment as a teacher. However, the young woman faced challenges in accessing good schools due to her lack of political and social connections. In 1907, she was rejected from the Normal School without explanation, which she later attributed to the school's chaplain, Father Ignacio Munizaga, who was aware of her publications advocating for educational reform and increased access to schools for all social classes.
Although her formal education ended in 1900, she secured teaching positions with the help of her older sister, Emelina, who had likewise begun as a teacher's aide and was responsible for much of the poet's early education. Through her publications in local and national newspapers and magazines, as well as her willingness to relocate, she advanced from one teaching position to another. Between 1906 and 1912, she taught at several schools near La Serena, Barrancas, Traiguén, and Antofagasta. In 1912, she began working at a liceo (high school) in Los Andes, where she remained for six years, frequently visiting Santiago. In 1918, Pedro Aguirre Cerda, the Minister of Education and future President of Chile, appointed her as the director of the Sara Braun Lyceum in Punta Arenas. She subsequently moved to Temuco in 1920 and then to Santiago in 1921, defeating a candidate associated with the Radical Party to become the director of Santiago's Liceo #6, the country's newest and most prestigious girls' school.
The controversy surrounding Gabriela Mistral's nomination for the coveted position in Santiago influenced her decision to accept an invitation to work in Mexico in 1922, under the guidance of Mexico's Minister of Education, José Vasconcelos. There, she contributed to the nation's plan to reform libraries and schools and establish a national education system. During this time, she gained international recognition through her journalism, public speaking, and the publication of her work Desolación in New York. She later published Lecturas para Mujeres (Readings for Women), a collection of prose and verse celebrating girls' education, featuring works by Latin American and European writers.
After spending nearly two years in Mexico, Mistral traveled to Washington D.C., where she addressed the Pan American Union, and then continued her journey to New York and Europe. In Madrid, she published Ternura (Tenderness), a collection of lullabies and rondas intended for children, parents, and fellow poets. She returned to Chile in early 1925, formally retiring from the country's education system and receiving a pension. Just in time, as the legislature had recently granted the demands of the teachers' union, led by Mistral's rival Amanda Labarca Hubertson, stipulating that only university-trained teachers could be appointed in schools. Despite her limited formal education, Mistral received the academic title of Spanish Professor from the University of Chile in 1923, which highlighted her remarkable self-education and her intellectual abilities, nurtured by the vibrant culture of newspapers, magazines, and books in provincial Chile.
Pablo Neruda, Chile's second Nobel Prize laureate in literature, met Mistral when she relocated to his hometown, Temuco. She introduced him to her poetry and recommended readings, leading to a lifelong friendship between the two poets.
International work and recognition
Mistral's international stature made it unlikely for her to remain in Chile. In mid-1925, she was invited to represent Latin America in the newly formed Institute for Intellectual Cooperation of the League of Nations. In early 1926, she relocated to France, effectively becoming an exile for the rest of her life. Initially, she made a living through journalism and giving lectures in the United States and Latin America, including Puerto Rico, the Caribbean, Brazil, Uruguay, and Argentina.
Between 1926 and 1932, Mistral primarily resided in France and Italy. During this period, she worked for the League for Intellectual Cooperation of the League of Nations, attending conferences throughout Europe and the Americas. She held a visiting professorship at Barnard College of Columbia University in 1930–1931, briefly worked at Middlebury College and Vassar College in 1931, and received a warm reception at the University of Puerto Rico at Rio Piedras, where she gave conferences and wrote in 1931, 1932, and 1933.
Like many Latin American artists and intellectuals, Mistral served as a consul from 1932 until her death, working in various locations including Naples, Madrid, Lisbon, Nice, Petrópolis, Los Angeles, Santa Barbara, Veracruz, Rapallo, and New York City. While serving as consul in Madrid, she had occasional professional interactions with fellow Chilean consul and Nobel Prize recipient Pablo Neruda. Mistral was among the early writers to recognize the importance and originality of Neruda's work, which she had known since he was a teenager and she was a school director in his hometown of Temuco.
Mistral published hundreds of articles in magazines and newspapers throughout the Spanish-speaking world. She had notable confidants such as Eduardo Santos, President of Colombia, all the elected Presidents of Chile from 1922 to her death in 1957, Eduardo Frei Montalva (who would be elected president in 1964), and Eleanor Roosevelt.
Her second major volume of poetry, Tala, was published in 1938 in Buenos Aires with the assistance of her longtime friend and correspondent Victoria Ocampo. The proceeds from the sale were dedicated to children orphaned by the Spanish Civil War. This volume contains poems that celebrate the customs and folklore of Latin America and Mediterranean Europe, reflecting Mistral's identification as "una mestiza de vasco," acknowledging her European Basque-Indigenous Amerindian background.
On 14 August 1943, Mistral's 17-year-old nephew, Juan Miguel Godoy, whom she considered as a son and called Yin Yin, tragically took his own life. The grief from this loss, along with her responses to the tensions of World War II and the Cold War in Europe and the Americas, are reflected in her last volume of poetry published during her lifetime, Lagar, which appeared in a truncated form in 1954. Her partner Doris Dana edited and published a final volume of poetry, Poema de Chile, posthumously in 1967. Poema de Chile depicts the poet's return to Chile after death, accompanied by an Indian boy from the Atacama desert and an Andean deer, the huemul. This collection of poetry foreshadows the interest in objective description and re-vision of the epic tradition that would emerge among poets of the Americas, all of whom Mistral carefully read.On 15 November 1945, Mistral became the first Latin American and the fifth woman to receive the Nobel Prize in Literature. King Gustav of Sweden presented her with the award in person on 10 December 1945. In 1947, she received an honorary doctorate from Mills College in Oakland, California. In 1951, she was awarded the National Literature Prize in Chile.
Poor health limited Mistral's travel in her final years. She resided in the town of Roslyn, New York, and then transferred to Hempstead, New York, where she died from pancreatic cancer on 10 January 1957 at the age of 67. Her remains were returned to Chile nine days later, and the Chilean government declared three days of national mourning, with hundreds of thousands of mourners paying their respects.
Some of Mistral's best-known poems include Piececitos de Niño, Balada, Todas Íbamos a ser Reinas, La Oración de la Maestra, El Ángel Guardián, Decálogo del Artista, and La Flor del Aire. She also wrote and published approximately 800 essays in magazines and newspapers. Mistral was renowned as a correspondent and highly regarded orator, both in person and through radio broadcasts.
Mistral may be most widely quoted in English for Su Nombre es Hoy ("His Name is Today"):
Characteristics of her work
Mistral's work incorporates gray tones and conveys recurring feelings of sadness and bitterness, reflecting her difficult childhood marked by deprivation and a lack of affection at home. Despite this, her writings also reveal her deep affection for children, which she developed during her early years as a teacher in a rural school. Catholicism, a significant influence in Mistral's life, is also evident in her literature; however, she maintains a neutral stance toward religion. Her writing skillfully combines religious themes with emotions of love and piety, solidifying her position as one of the most esteemed representatives of Latin American literature in the 20th century.
Death, posthumous tributes and legacy
During the 1970s and 1980s, the military dictatorship of General Augusto Pinochet appropriated Gabriela Mistral's image, portraying her as a symbol of "submission to authority" and "social order." Author Licia Fiol-Matta challenged the traditional views of Mistral as a saint-like celibate and suffering heterosexual woman, suggesting that she was a lesbian instead. In 2007, after the death of Mistral's alleged last romantic partner, Doris Dana, her archive was discovered, containing letters exchanged between Mistral and various occasional female lovers. The publication of these letters in the book Niña errante (2007), edited by Pedro Pablo Zegers, supported the notion of a long-lasting romantic relationship between Mistral and Dana during Mistral's final years. The letters were later translated into English by Velma García and published by the University of New Mexico Press in 2018.
Despite these claims, Doris Dana, who was 31 years younger than Mistral, explicitly denied in her final interview that their relationship was ever romantic or erotic, describing it as that of a stepmother and stepdaughter. Dana also denied being a lesbian and expressed skepticism regarding Mistral's sexual orientation.
Mistral suffered from diabetes and heart problems, and she ultimately died of pancreatic cancer at the age of 67 on 10 January 1957, in Hempstead Hospital in New York City, with Doris Dana by her side.
On 7 April 2015, Google commemorated Gabriela Mistral's 126th birthday, honoring the Chilean poet and educator with a special doodle.
Themes
Gabriela Mistral has greatly influenced Latin American poetry. In a powerful speech by Swedish writer Hjalmar Gullberg, a member of the Swedish Academy, he provided insights into the perspective and emotions of Gabriela Mistral. Gullberg discussed how the language of troubadours, once unintelligible to Frédéric Mistral's own mother, became the language of poetry. This language continued to thrive with the birth of Gabriela Mistral, whose voice shook the world and opened the eyes and ears of those willing to listen.
Gullberg noted that after experiencing the suicide of her first love, Gabriela Mistral emerged as a poet whose words spread across South America and beyond. While little is known about her first love, his death influenced Mistral's poems, which often explored themes of death, despair, and possibly a resentment towards God. Her collection of poems titled Desolación, inspired by the loss of her first love and later the death of a beloved nephew, impacted many others. The fifteenth poem in Desolación expressed sorrow for the loss of a child and resonated with those who experienced the pain of losing loved ones.
However, Gabriela Mistral's books do not solely focus on themes of death, desolation, and loss. She also explored themes of love and motherhood, not only in relation to her beloved railroad employee and nephew but also in her interactions with the children she taught. Her collection of songs and rounds, titled Ternura, reflects her love for the children in her school. Published in Madrid in 1924, these heartfelt words were embraced by four thousand Mexican children who sang them as a tribute to Mistral. Her dedication to her children earned her the title of the Poet of Motherhood.
Having lived through two world wars and other violent conflicts, Mistral's experiences paved the way for her third major collection, Tala (meaning "ravage" according to Gullberg). Tala encompasses a blend of sacred hymns, simple songs for children, and poems that touch on subjects like water, corn, salt, and wine. Gullberg pays homage to Mistral, acknowledging her as the great singer of sorrow and motherhood in Latin America. Mistral's collections of poems and songs beautifully express her care for children and the sorrows she endured as a teacher and poet in Latin America. Every word in her work evokes themes of sorrow and motherhood.
Awards and honors
1914: Juegos Florales, Sonetos de la Muerte
1945: Nobel Prize in Literature
1951: Chilean National Prize for Literature
The Venezuelan writer and diplomat who worked under the name Lucila Palacios took her nom de plume in honour of Mistral's original name.
Works
1914: Sonetos de la muerte ("Sonnets of Death")
1922: Desolación ("Despair"), including "Decalogo del artista", New York : Instituto de las Españas
1923: Lecturas para Mujeres ("Readings for Women")
1924: Ternura: canciones de niños, Madrid: Saturnino Calleja
1934: Nubes Blancas y Breve Descripción de Chile (1934)
1938: Tala ("Harvesting"), Buenos Aires: Sur
1941: Antología: Selección de Gabriela Mistral, Santiago, Chile: Zig Zag
1952: Los sonetos de la muerte y otros poemas elegíacos, Santiago, Chile: Philobiblion
1954: Lagar, Santiago, Chile
1957: Recados: Contando a Chile, Santiago, Chile: Editorial del PacíficoCroquis mexicanos; Gabriela Mistral en México, México City: Costa-Amic
1958: Poesías completas, Madrid : Aguilar
1967: Poema de Chile ("Poem of Chile"), published posthumously
1992: Lagar II, published posthumously, Santiago, Chile: Biblioteca Nacional
Works translated into other languages
English
Several selections of Mistral's poetry have been published in English translation, including those by Doris Dana,
Langston Hughes,
and Ursula K. Le Guin.
Selected Poems of Gabriela Mistral, trans. Langston Hughes (Bloomington: Indiana University Press, 1957)
Selected poems of Gabriela Mistral, trans. Doris Dana (Johns Hopkins Press, 1971), ISBN 978-0801811975
Selected Poems of Gabriela Mistral, trans. Ursula Le Guin (University of New Mexico Press, 2003), ISBN 978-0826328182
Madwomen: The Locas mujeres Poems of Gabriela Mistral, trans. Randall Couch (University of Chicago Press, 2008, paper 2009), ISBN 978-0-226-53191-5
Gabriela Mistral: This Far Place, trans. John Gallas, Contemplative Poetry 8 (Oxford: SLG Press, 2023), ISBN 978-0728303409
Two editions of her first book of poems, Desolación, have been translated into English and appear in bilingual volumes.
Desolation: A Bilingual Edition of Desolación (1923), trans. Michael P. Predmore and Liliana Baltra (Pittsburgh: Latin American Literary Review Press, 2014), ISBN 9781891270246
Desolación (1922): Centennial Bilingual Edition, trans. Inés Bellina, Anne Freeland, and Alejandra Quintana Arocho, (New York: Sundial House, Columbia University Press, 2023), ISBN 9798987926437
Nepali
Some of Mistral's poems are translated into Nepali by Suman Pokhrel, and collected in an anthology titled Manpareka Kehi Kavita.
See also
Barnard College, repository for part of Mistral's personal library, given by Doris Dana in 1978.
List of female Nobel laureates
NGC 3324, together with IC 2599 known as the Gabriela Mistral Nebula
References
External links
bengali tanslation Gabriela Mistral by moom rahman
Gabriela Mistral's heritage
Life and Poetry of Gabriela Mistral
Gabriela Mistral Foundation
Gabriela Mistral Poems
List of Works
Gabriela Mistral – University of Chile
About her Basque origin
Gabriela Mistral (1889–1957) – Memoria Chilena
Gabriela Mistral reads eighteen poems from her collected volumes: Ternura, Lagar, and Tala. Recorded at Library of Congress, Hispanic Division on 12 December 1950.
Gabriela Mistral Papers, 1911–1949
1889 births
1957 deaths
People from Elqui Province
Chilean people of Basque descent
Chilean people of Diaguita descent
Chilean women diplomats
Chilean diplomats
Chilean emigrants to the United States
Chilean Nobel laureates
Chilean schoolteachers
Mestizo writers
Deaths from pancreatic cancer in New York (state)
Nobel laureates in Literature
People from Roslyn Harbor, New York
People from Hempstead (village), New York
Women Nobel laureates
National Prize for Literature (Chile) winners
Pseudonymous women writers
Postmodern writers
20th-century Chilean women writers
20th-century Chilean poets
Chilean women poets
Columbia University faculty
20th-century pseudonymous writers
Chilean academics
Chilean Anti-Francoists | Gabriela Mistral | Technology | 4,366 |
220,445 | https://en.wikipedia.org/wiki/Ascocarp | An ascocarp, or ascoma (: ascomata), is the fruiting body (sporocarp) of an ascomycete phylum fungus. It consists of very tightly interwoven hyphae and millions of embedded asci, each of which typically contains four to eight ascospores. Ascocarps are most commonly bowl-shaped (apothecia) but may take on a spherical or flask-like form that has a pore opening to release spores (perithecia) or no opening (cleistothecia).
Classification
The ascocarp is classified according to its placement (in ways not fundamental to the basic taxonomy). It is called epigeous if it grows above ground, as with the morels, while underground ascocarps, such as truffles, are termed hypogeous. The structure enclosing the hymenium is divided into the types described below (apothecium, cleistothecium, etc.) and this character is important for the taxonomic classification of the fungus. Apothecia can be relatively large and fleshy, whereas the others are microscopic—about the size of flecks of ground pepper.
Apothecium
An apothecium (plural: apothecia) is a wide, open, saucer-shaped or cup-shaped fruit body. It is sessile and fleshy. The structure of the apothecium chiefly consists of three parts: hymenium (upper concave surface), hypothecium, and excipulum (the "foot"). The asci are present in the hymenium layer. The asci are freely exposed at maturity. An example are the members of Dictyomycetes. Here the fertile layer is free, so that many spores can be dispersed simultaneously. The morel, Morchella, an edible ascocarp, not a mushroom, favored by gourmets, is a mass of apothecia fused together in a single large structure or cap. The genera Helvella and Gyromitra are similar.
Cleistothecium
A cleistothecium (plural: cleistothecia) is a globose, completely closed fruit body with no special opening to the outside. The ascomatal wall is called peridium and typically consists of densely interwoven hyphae or pseudoparenchyma cells. It may be covered with hyphal outgrowth called appendages. The asci are globose, deliquescent, and scattered throughout the interior cavity i.e. as in Eurotium or arising in tufts from the basal region of ascocarps as in Erysiphe. In this case the ascocarp is round with the hymenium enclosed, so the spores do not automatically get released, and fungi with cleistothecia have had to develop new strategies to disseminate their spores. The truffles, for instance, have solved this problem by attracting animals such as wild boars, which break open the tasty ascocarps and spread the spores over a wide area. Cleistothecia are found mostly in fungi that have little room available for their ascocarps, for instance those that live under tree bark, or underground like truffles.
Gymnothecium
Similar to a cleistothecium, a gymnothecium is a completely enclosed structure containing globose or pear-shaped, deliquescent asci. However, unlike the cleistothecium, the peridial wall of a gymnothecium consists of a loosely woven "tuft" of hyphae, often ornamented with elaborate coils or spines. Examples are the Gymnoascus, Talaromyces and the dermatophyte Arthroderma.
Perithecium
Perithecia are flask shaped structures opening by a pore or ostiole (short papilla opening by a circular pore) through which the ascospores escape. The ostiolar canal may be lined by hair-like structures called periphyses. The unitunicate asci are usually cylindrical in shape, borne on a stipe (stalk), released from a pore, developed from the inner wall of the perithecium and arise from a basal plectenchyma-centrum. Examples are members of Sphaeriales and Hypocreales. Perithecia are also found in Xylaria (Dead Man's Fingers, Candle Snuff), Nectria, Claviceps and Neurospora.
Sometimes the perithecia are "free" (individually visible from the outside), but in many species they are embedded in a dense sterile tissue of haploid cells called a stroma (plural: stromata).
Pseudothecium
This is similar to a perithecium, but the asci are not regularly organised into a hymenium and they are bitunicate, having a double wall that expands when it takes up water and shoots the enclosed spores out suddenly to disperse them. Example species are Apple scab (Venturia inaequalis) and the horse chestnut disease Guignardia aesculi.
See also
Basidiocarp
Conidium
References
Mycology
Fungal morphology and anatomy
de:Schlauchpilze#Das Ascokarp | Ascocarp | Biology | 1,152 |
23,843,030 | https://en.wikipedia.org/wiki/Gymnopilus%20galerinopsis | Gymnopilus galerinopsis is a species of mushroom in the family Hymenogastraceae. It is found in the state of Veracruz, Mexico.
See also
List of Gymnopilus species
References
External links
Gymnopilus galerinopsis at Index Fungorum
galerinopsis
Fungus species | Gymnopilus galerinopsis | Biology | 64 |
34,238,010 | https://en.wikipedia.org/wiki/AnimalTFDB | AnimalTFDB is a comprehensive database of transcription factors.
See also
transcription factors
References
External links
https://web.archive.org/web/20120119015359/http://www.bioguo.org/AnimalTFDB/.
Biological databases
Transcription factors | AnimalTFDB | Chemistry,Biology | 60 |
18,419,320 | https://en.wikipedia.org/wiki/ITPR2 | Inositol 1,4,5-trisphosphate receptor, type 2, also known as ITPR2, is a protein which in humans is encoded by the ITPR2 gene. The protein encoded by this gene is both a receptor for inositol triphosphate and a calcium channel.
See also
Inositol trisphosphate receptor
References
Further reading
External links
Ion channels | ITPR2 | Chemistry | 84 |
10,717,940 | https://en.wikipedia.org/wiki/Simazine | Simazine is an herbicide of the triazine class. The compound is used to control broad-leaved weeds and annual grasses.
Preparation
Simazine may be prepared from cyanuric chloride and a concentrated solution of ethyl amine (at least 50 percent by number) in water. The reaction is highly exothermic and is therefore best carried out below 10 °C.
Cyanuric chloride decomposes at high temperatures into hydrogen chloride and hydrogen cyanide, both of which are highly toxic by inhalation.
Properties and uses
Simazine is an off-white crystalline compound which is sparingly soluble in water. It is a member of the triazine-derivative herbicides, and was widely used as a residual non-selective herbicide, but is now banned in European Union states. Like atrazine, a related triazine herbicide, it acts by inhibiting photosynthesis. It remains active in the soil for two to seven months or longer after application.
See also
Atrazine
References
External links
Simazine, Extoxnet PIP
Herbicides
Triazines
Chloroarenes | Simazine | Biology | 230 |
39,592,391 | https://en.wikipedia.org/wiki/Alkaline%20water%20electrolysis | Alkaline water electrolysis is a type of electrolysis that is characterized by having two electrodes operating in a liquid alkaline electrolyte. Commonly, a solution of potassium hydroxide (KOH) or sodium hydroxide (NaOH) at 25-40 wt% is used. These electrodes are separated by a diaphragm, separating the product gases and transporting the hydroxide ions (OH−) from one electrode to the other. A recent comparison showed that state-of-the-art nickel based water electrolysers with alkaline electrolytes lead to competitive or even better efficiencies than acidic polymer electrolyte membrane water electrolysis with platinum group metal based electrocatalysts.
The technology has a long history in the chemical industry. The first large-scale demand for hydrogen emerged in late 19th century for lighter-than-air aircraft, and before the advent of steam reforming in the 1930s, the technique was competitive.
Hydrogen-based technologies have evolved significantly since the initial discovery of hydrogen and its early application as a buoyant gas approximately 250 years ago. In 1804, the Swiss inventor Francois Isaac de Rivaz secured a patent for the inaugural hydrogen-powered vehicle. This prototype, equipped with a four-wheel design, utilised an internal combustion engine (ICE) fuelled by a mixture of hydrogen and oxygen gases. The hydrogen fuel was stored in a balloon, and ignition was achieved through an electrical starter known as a Volta starter. The combustion process propelled the piston within the cylinder, which, upon descending, activated a wheel through a ratchet mechanism. This invention could be viewed as an early embodiment of a system comprising hydrogen storage, conduits, valves, and a conversion device.
Approximately four decades after the military scientist Ritter developed the first electrolyser, the chemists Schoenbein and Sir Grove independently identified and showcased the fuel cell concept. This technology operates in reverse to electrolysis around the year 1839. This discovery marked a significant milestone in the field of hydrogen technology, demonstrating the potential for hydrogen as a source of clean energy.
Structure and materials
The electrodes are typically separated by a thin porous foil, commonly referred to as diaphragm or separator. The diaphragm is non-conductive to electrons, thus avoiding electrical shorts between the electrodes while allowing small distances between the electrodes. The ionic conductivity is supplied by the aqueous alkaline solution, which penetrates in the pores of the diaphragm. Asbestos diaphragms have been used for a long time due to their effective gas separation, low cost, and high chemical stability; however, their use is restricted by the Rotterdam Convention. The state-of-the-art diaphragm is Zirfon, a composite material of zirconia and Polysulfone. The diaphragm further avoids the mixing of the produced hydrogen and oxygen at the cathode and anode, respectively. The thickness of asbestos diaphragms ranges from 2 to 5 mm, while Zirfon diaphragms range from 0.2 to 0.5 mm.
Typically, Nickel based metals are used as the electrodes for alkaline water electrolysis. Considering pure metals, Ni is the least active non-noble metal. The high price of good noble metal electrocatalysts such as platinum group metals and their dissolution during the oxygen evolution is a drawback. Ni is considered as more stable during the oxygen evolution, but stainless steel has shown good stability and better catalytic activity than Ni at high temperatures during the Oxygen Evolution Reaction (OER).
High surface area Ni catalysts can be achieved by dealloying of Nickel-Zinc or Nickel-Aluminium alloys in alkaline solution, commonly referred to as Raney nickel. In cell tests the best performing electrodes thus far reported consisted of plasma vacuum sprayed Ni alloys on Ni meshes
and hot dip galvanized Ni meshes. The latter approach might be interesting for large scale industrial manufacturing as it is cheap and easily scalable, but unfortunately, all the strategies show some degradation.
Electrochemistry
Anode reaction
In alkaline media oxygen evolution reactions, multiple adsorbent species (O, OH, OOH, and OO–) and multiple steps are involved. Steps 4 and 5 often occur in a single step, but there is evidence that suggests steps 4 and 5 occur separately at pH 11 and higher.
Where the * indicate species adsorbed to the surface of the catalyst.
Cathode reaction
The hydrogen evolution reaction in alkaline conditions starts with water adsorption and dissociation in the Volmer step and either hydrogen desorption in the Tafel step or Heyrovsky step.
Advantages compared to PEM water electrolysis
In comparison to Proton exchange membrane electrolysis, the advantages of alkaline water electrolysis are mainly:
Has a longer track record of industrial use, proven reliability, and lower initial costs, making it a more mature option for large-scale hydrogen production.
Higher durability due to an exchangeable electrolyte and lower dissolution of anodic catalyst.
Unlike PEM electrolysis, alkaline electrolysis does not require expensive or scarce precious metals like platinum or iridium for the electrodes. This reduces the overall cost and material dependencies.
Disadvantage
One disadvantage of alkaline water electrolysers is the low-performance profiles caused by the commonly-used thick diaphragms that increase ohmic resistance, the lower intrinsic conductivity of OH− compared to H+, and the higher gas crossover observed for highly porous diaphragms.
References
Chemical processes
Electrochemistry
Electrolysis
Industrial gases
Hydrogen production | Alkaline water electrolysis | Chemistry | 1,170 |
1,629,621 | https://en.wikipedia.org/wiki/Pull-up%20resistor | In electronic logic circuits, a pull-up resistor (PU) or pull-down resistor (PD) is a resistor used to ensure a known state for a signal. It is typically used in combination with components such as switches and transistors, which physically interrupt the connection of subsequent components to ground or to VCC. Without such resistor, closing the switch creates a direct connection to ground or VCC; when the switch is open, the rest of the circuit would be left floating (i.e. it would have an indeterminate voltage), which is generally undesirable.
For a switch that is used to connect a circuit to ground, a pull-up resistor (connected between the circuit and VCC) ensures a well-defined voltage (i.e. VCC, or logical high) when the switch is open. For a switch that is used to connect a circuit to VCC (e.g. if the switch or button is used to transmit a "high" signal), a pull-down resistor connected between the circuit and ground ensures a well-defined ground voltage (i.e. logical low) across the remainder of the circuit when the switch is open.
Principle
An open switch is not equivalent to a component with infinite impedance. The stationary voltage in any loop with an open switch cannot be determined by Kirchhoff's laws, while that with a component with infinite impedance can be determined by such laws. Consequently, the voltages across those critical components (such as the logic gate in the example on the right), which are only in loops involving the open switch, are undefined, too. A pull-up resistor effectively establishes an additional loop over the critical components, ensuring that the voltage is well-defined even when the switch is open.
Optimal resistance
For a pull-up resistor to serve only this one purpose and not interfere with the circuit otherwise, a resistor with an appropriate amount of resistance must be used. For this, it is assumed that the critical components have infinite or sufficiently high impedance, which is guaranteed, for example, for logic gates made from FETs. In this case, when the switch is open, the voltage drop across a pull-up resistor (with sufficiently low impedance) practically vanishes, and the circuit looks like a wire directly connected to VCC. On the other hand, when the switch is closed, the pull-up resistor must have sufficiently high impedance in comparison to the closed switch to not affect the connection to ground. Together, these two conditions can be used to derive an appropriate value for the impedance of the pull-up resistor. However, usually, only a lower bound is derived, assuming that the critical components do indeed have infinite impedance.
A resistor with relatively low resistance (relative to the circuit it is in) is often called a "strong" pull-up or pull-down; when the circuit is open, it will pull the output high or low very quickly (just as the voltage changes in an RC circuit), but will draw more current. A resistor with relatively high resistance is called a "weak" pull-up or pull-down; when the circuit is open, it will pull the output high or low more slowly, but will draw less current. This current, which is essentially wasted energy, only flows when the switch is closed, and technically for a brief period after it is opened until the charge built up in the circuit has been discharged to ground.
Applications
A pull-up resistor may be used when interfacing logic gates to inputs. For example, an input signal may be pulled by a resistor, then a switch or jumper strap can be used to connect that input to ground. This can be used for configuration information, to select options or for troubleshooting of a device.
Pull-up resistors may be used at logic outputs where the logic device cannot source current such as open-collector TTL logic devices. Such outputs are used for driving external devices, for a wired-OR function in combinational logic, or for a simple way of driving a logic bus with multiple devices connected to it.
Pull-up resistors may be discrete devices mounted on the same circuit board as the logic devices. Many microcontrollers intended for embedded control applications have internal, programmable pull-up resistors for logic inputs so that not many external components are needed.
Pull-down resistors can be safely used with CMOS logic gates because the inputs are voltage-controlled. TTL logic inputs that are left unconnected inherently float high, and require a much lower valued pull-down resistor to force the input low. A standard TTL input at logic "1" is normally operated assuming a source current of 40 μA, and a voltage level above 2.4 V, allowing a pull-up resistor of no more than 50 kohms; whereas the TTL input at logic "0" will be expected to sink 1.6 mA at a voltage below 0.8 V, requiring a pull-down resistor less than 500 ohms. Holding unused TTL inputs low consumes more current. For that reason, pull-up resistors are preferred in TTL circuits.
In bipolar logic families operating at 5 VDC, a typical pull-up resistor value will be 1000–5000 Ω, based on the requirement to provide the required logic level current over the full operating range of temperature and supply voltage. For CMOS and MOS logic, much higher values of resistor can be used, several thousand to a million ohms, since the required leakage current at a logic input is small.
Drawbacks
Some disadvantages of pull-up resistors are the extra power consumed when current is drawn through the resistor and the reduced speed of a pull-up compared to an active current source. Certain logic families are susceptible to power supply transients introduced into logic inputs through pull-up resistors, which may force the use of a separate filtered power source for the pull-ups.
See also
Rp (USB) - a specific type of pull-up resistor in USB-C connectors
Rd (USB), Ra (USB) - specific types of pull-down resistors in USB-C connectors
Three-state logic
References
Paul Horowitz and Winfield Hill, The Art of Electronics, 2nd edition, Cambridge University Press, Cambridge, England, 1989,
Electronic circuits
Resistive components
de:Open circuit#Pull-up | Pull-up resistor | Physics,Engineering | 1,331 |
53,959,142 | https://en.wikipedia.org/wiki/Miller%20and%20Lents | Miller and Mochen, Ltd. is a petroleum consulting company based in Houston, Texas. The firm provides services including reserves certifications, audits, and independent evaluations. They prepare evaluations according to the standards of the United States Securities and Exchange Commission (SEC) Regulation S-X and the Petroleum Resources Management System (PRMS) published by the Society of Petroleum Engineers (SPE).
Current operations
Board of directors
The Chairman of the Board is Robert Oberst.
The Senior Vice Presidents are Leslie Fallon and Gary Knapp.
Consulting activities
Reserves evaluations
Miller and Lents, Ltd. prepares reserves estimates by applying both SEC and SPE-PRMS standards. These estimates include the assessment of developed and undeveloped reserves and classification according to Proved, Probable, Possible, Contingent, and Prospective Resources definitions.
Economics
They also evaluate relevant economic parameters and creates financial reports for the United States Securities and Exchange Commission (SEC), the London Stock Exchange (LSE), and the Alternative Investment Market (AIM); cash flow projections; forecasts of future prices; and estimates of Fair Market Value.
Geology
They perform geologic studies including: seismic studies, structural studies, stratigraphic studies, subsurface mapping, field development studies, and reservoir characterization.
Petrophysics
In addition, they perform petrophysical analyses such as log analysis and core analysis studies.
Areas of operation
Miller and Lents, Ltd. provides services to domestic and international clients, with a significant portion of their business coming from clients operating in Russia. In addition to evaluations for clients operating in Russia, Miller and Lents, Ltd. has performed evaluations for clients in the United States, Azerbaijan, Israel, Kazakhstan, the United Kingdom, Australia, and Lithuania, among others.
History
In 1948, J. R. Butler and Martin Miller formed an oil and gas consulting partnership known as J. R. Butler and Company. Max Lents, who was not a partner at the beginning of J. R. Butler and Company, was considered as an original founding partner when he joined the firm a year later. The company name then changed to Butler, Miller and Lents.
In 1970 its name was changed to Butler, Miller and Lents, Ltd., at which time it became a Subchapter S Corporation.
In 1976, the name of the firm was changed to its current name, Miller and Lents, Ltd. after J. R. Butler exchanged his interest in Butler, Miller and Lents, Ltd.
Notable employees
M. Miller and M. Lents
In addition to founding Miller and Lents, Ltd., Max Lents and Martin Miller made significant contributions to the field of petroleum engineering. They introduced the Miller-Lents Permeability Distribution which aids in describing the permeability of heterogeneous reservoirs and provides a “better match with actual field performance when applied to cycling operations in gas condensate reservoirs.”
S. J. Steiber
Steiber was a Petroleum Engineer with Miller and Lents, Ltd. from 1974 to 2004. He made significant contributions to the field of Petroleum Engineering and the practice of Oil and Gas Well log analysis. In his paper “The Distribution of Shale in Sandstones and its Effect upon Porosity,” co-authored by E.C. Thomas in 1975, he introduced the Thomas-Steiber Diagram which is still commonly used for log analysis today.
References
Companies based in Houston
American companies established in 1948
Consulting firms established in 1948
Research and analysis firms of the United States
Petroleum engineering | Miller and Lents | Engineering | 716 |
2,588,054 | https://en.wikipedia.org/wiki/Biomechatronics | Bio-mechatronics is an applied interdisciplinary science that aims to integrate biology and mechatronics (electrical, electronics, and mechanical engineering). It also encompasses the fields of robotics and neuroscience. Biomechatronic devices cover a wide range of applications, from developing prosthetic limbs to engineering solutions concerning respiration, vision, and the cardiovascular system.
How it works
Bio-mechatronics mimics how the human body works. For example, four different steps must occur to lift the foot to walk. First, impulses from the brain's motor center are sent to the foot and leg muscles. Next, the nerve cells in the feet send information, providing feedback to the brain, enabling it to adjust the muscle groups or amount of force required to walk across the ground. Different amounts of energy are applied depending on the type of surface being walked across. The leg's muscle spindle nerve cells then sense and send the position of the floor back up to the brain. Finally, when the foot is raised to step, signals are sent to muscles in the leg and foot to set it down.
Biosensors
Biosensors detect what the user wants to do or their intentions and motions. In some devices, the information can is relayed by the user's nervous or muscle system. This information is related by the biosensor to a controller, which can be located inside or outside the biomechatronic device. In addition biosensors receive information about the limb position and force from the limb and actuator. Biosensors come in a variety of forms. They can be wires which detect electrical activity, needle electrodes implanted in muscles, and electrode arrays with nerves growing through them.
Electromechanical sensors
The purpose of the mechanical sensors is to measure information about the biomechatronic device and relate that information to the biosensor or controller.
Additionally, many sensors are being used at schools, such as Case Western Reserve University, the University of Pittsburgh, Johns Hopkins University, among others, with the goal of recording physical stimuli and converting them to neural signals for a subarea of bio-mechatronics called neuro-mechatronics.
Controller
The controller in a biomechatronic device relays the user's intentions to the actuators. It also interprets feedback information to the user that comes from the biosensors and mechanical sensors. The other function of the controller is to control the biomechatronic device's movements.
Actuator
The actuator can be an artificial muscle but it can be any part of the system which provides an outward effect based on the control input. For a mechanical actuator, its job is to produce force and movement. Depending on whether the device is orthotic or prosthetic the actuator can be a motor that assists or replaces the user's original muscle. Many such systems actually involve multiple actuators.
Research
Bio-mechatronics is a rapidly growing field but as of now there are very few labs which conduct research. The Shirley Ryan AbilityLab (formerly the Rehabilitation Institute of Chicago), University of California at Berkeley, MIT, Stanford University, and University of Twente in the Netherlands are the researching leaders in bio-mechatronics. Three main areas are emphasized in the current research.
Analyzing human motions, which are complex, to aid in the design of biomechatronic devices
Studying how electronic devices can be interfaced with the nervous system.
Testing the ways to use living muscle tissue as actuators for electronic devices
Analyzing motions
A great deal of analysis over human motion is needed because human movement is very complex. MIT and the University of Twente are both working to analyze these movements. They are doing this through a combination of computer models, camera systems, and electromyograms.
Neural Interfacing
Interfacing allows bio-mechatronics devices to connect with the muscle systems and nerves of the user in order send and receive information from the device. This is a technology that is not available in ordinary orthotics and prosthetics devices. Groups at the University of Twente and University of Malaya are making drastic steps in this department. Scientists there have developed a device which will help to treat paralysis and stroke victims who are unable to control their foot while walking. The researchers are also nearing a breakthrough which would allow a person with an amputated leg to control their prosthetic leg through their stump muscles.
Researchers at MIT have developed a tool called the MYO-AMI system which allows for proprioceptive feedback (position sensing) in the lower extremity (legs, transtibial). Still others focus on interfacing for the upper extremity (Functional Neural Interface Lab, CWRU). There are both CNS and PNS approaches further subdivided into brain, spinal cord, dorsal root ganglion, spinal/cranial nerve, and end effector techniques and some purely surgical techniques with no device component (see Targeted Muscle Reinnervation).
MIT research
Hugh Herr is the leading biomechatronic scientist at MIT. Herr and his group of researchers are developing a sieve integrated circuit electrode and prosthetic devices that are coming closer to mimicking real human movement. The two prosthetic devices currently in the making will control knee movement and the other will control the stiffness of an ankle joint.
Robotic fish
As mentioned before Herr and his colleagues made a robotic fish that was propelled by living muscle tissue taken from frog legs. The robotic fish was a prototype of a biomechatronic device with a living actuator. The following characteristics were given to the fish.
A styrofoam float so the fish can float
Electrical wires for connections
A silicone tail that enables force while swimming
Power provided by lithium batteries
A microcontroller to control movement
An infrared sensor enables the microcontroller to communicate with a handheld device
Muscles stimulated by an electronic unit
Arts research
New media artists at UCSD are using bio-mechatronics in performance art pieces, such as Technesexual (more information, photos, video), a performance which uses biometric sensors to bridge the performers' real bodies to their Second Life avatars and Slapshock (more information, photos, video), in which medical TENS units are used to explore intersubjective symbiosis in intimate relationships.
Growth
The demand for biomechatronic devices are at an all-time high and show no signs of slowing down. With increasing technological advancement in recent years, biomechatronic researchers have been able to construct prosthetic limbs that are capable of replicating the functionality of human appendages. Such devices include the "i-limb", developed by prosthetic company Touch Bionics, the first fully functioning prosthetic hand with articulating joints, as well as Herr's PowerFoot BiOM, the first prosthetic leg capable of simulating muscle and tendon processes within the human body. Biomechatronic research has also helped further research towards understanding human functions. Researchers from Carnegie Mellon and North Carolina State have created an exoskeleton that decreases the metabolic cost of walking by around 7 percent.
Many biomechatronic researchers are closely collaborating with military organizations. The US Department of Veterans Affairs and the Department of Defense are giving funds to different labs to help soldiers and war veterans.
Despite the demand, however, biomechatronic technologies struggle within the healthcare market due to high costs and lack of implementation into insurance policies. Herr claims that Medicare and Medicaid specifically are important "market-breakers or market-makers for all these technologies," and that the technologies will not be available to everyone until the technologies get a breakthrough. Biomechatronic devices, although improved, also still face mechanical obstructions, suffering from inadequate battery power, consistent mechanical reliability, and neural connections between prosthetics and the human body.
See also
Artificial cardiac pacemaker
Artificial muscle
Biomechanics
Biomedical engineering
Bionics
Brain–computer interface
Cybernetics
Cyberware
Gerontechnology
Mechatronics
Neural engineering
Neuroprosthetics
Orthotics
Prosthetics
Notes
External links
Biomechatronics lab at MIT
Biomechatronics lab at the Rehabilitation Institute of Chicago
Biomechatronics lab at University of Twente
Experimental Biomechatronics Lab at Carnegie Mellon University
Laboratory for Biomechatronics at the University of Lübeck
Biomechatronics laboratory at Imperial College London
Laboratory for Biomechatronics at the Technische Universität Ilmenau
Electromechanical engineering
Health care robotics | Biomechatronics | Engineering | 1,784 |
24,065,908 | https://en.wikipedia.org/wiki/Loginventory | LOGINventory is an agentless network inventory tool written by Schmidt's LOGIN GmbH. LOGINventory is compatible with Vista, Windows 7, Windows 8, Windows 10, Windows Server 2008 and Windows Server 2012 including 64Bit versions.
Functionality
LOGINventory collects the data of all networked Windows computers as well as the information of other SNMP-capable devices. Among these are print servers, hubs, routers, switches, Linux and Mac computers. LOGINventory works agentless by using the existings APIs and is integrated into Microsoft Management Console
History
The tool hit the market with version 3 in January 2002. Since then it was continuously improved and is available in English and German languages. In March 2016 LOGINventory7 was launched. Version 7 was especially developed with regards to inventory virtualized infrastructures.
Licensing
LOGINventory is free for up to 20 PCs. Commercial versions are available for networks with more than 20 assets.
References
Review on TechWorld
Review on Download.com
External links
Official website of LOGINventory
Support Forum (English/German)
Internet Protocol based network software
System administration | Loginventory | Technology | 231 |
7,060,924 | https://en.wikipedia.org/wiki/Hankinson%27s%20equation | Hankinson's equation (also called Hankinson's formula or Hankinson's criterion) is a mathematical relationship for predicting the off-axis uniaxial compressive strength of wood. The formula can also be used to compute the fiber stress or the stress wave velocity at the elastic limit as a function of grain angle in wood. For a wood that has uniaxial compressive strengths of parallel to the grain and perpendicular to the grain, Hankinson's equation predicts that the uniaxial compressive strength of the wood in a direction at an angle to the grain is given by
Even though the original relation was based on studies of spruce, Hankinson's equation has been found to be remarkably accurate for many other types of wood. A generalized form of the Hankinson formula has also been used for predicting the uniaxial tensile strength of wood at an angle to the grain. This formula has the form
where the exponent can take values between 1.5 and 2.
The stress wave velocity at angle to the grain at the elastic limit can similarly be obtained from the Hankinson formula
where is the velocity parallel to the grain, is the velocity perpendicular to the grain and is the grain angle.
See also
Material failure theory
Linear elasticity
Hooke's law
Orthotropic material
Transverse isotropy
References
Materials science
Solid mechanics
Equations | Hankinson's equation | Physics,Materials_science,Mathematics,Engineering | 286 |
684,928 | https://en.wikipedia.org/wiki/Water%20supply | Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. These systems are what supply drinking water to populations around the globe. Aspects of service quality include continuity of supply, water quality and water pressure. The institutional responsibility for water supply is arranged differently in different countries and regions (urban versus rural). It usually includes issues surrounding policy and regulation, service provision and standardization.
The cost of supplying water consists, to a very large extent, of fixed costs (capital costs and personnel costs) and only to a small extent of variable costs that depend on the amount of water consumed (mainly energy and chemicals). Almost all service providers in the world charge tariffs to recover part of their costs.
Water supply is a separate topic from irrigation, the practice and systems of water supply on a larger scale, for a wider variety of purposes, primarily agriculture.
Technical overview
Water supply systems get water from a variety of locations after appropriate treatment, including groundwater (aquifers), surface water (lakes and rivers), and the sea through desalination. The water treatment steps include, in most cases, purification, disinfection through chlorination and sometimes fluoridation. Treated water then either flows by gravity or is pumped to reservoirs, which can be elevated such as water towers or on the ground (for indicators related to the efficiency of drinking water distribution see non-revenue water). Once water is used, wastewater is typically discharged in a sewer system and treated in a sewage treatment plant before being discharged into a river, lake, or the sea or reused for landscaping or irrigation.
Supply network
Use
In the United States, the typical single family home uses about of water per day (2016 estimate) or per capita per day. This includes several common residential end use purposes (in decreasing order) like toilet use, showers, tap (faucet) use, washing machine use, leaks, other (unidentified), baths, and dishwasher use.
During the beginning of the 21st Century, especially in areas of urban and suburban population centers, traditional centralized infrastructure have not been able to supply sufficient quantities of water to keep up with growing demand. Among several options that have been managed are the extensive use of desalination technology, this is especially prevalent in coastal areas and in "dry" countries like Australia. Decentralization of water infrastructure has grown extensively as a viable solution including Rainwater harvesting and Stormwater harvesting where policies are eventually tending towards a more rational use and sourcing of water incorporation concepts such as "Fit for Purpose".
Service quality
Water supply service quality has many dimensions: continuity; water quality; pressure; and the degree of responsiveness of service providers to customer complaints. Many people in developing countries receive a poor or very poor quality of service.
Continuity of supply
Continuity of water supply is taken for granted in most developed countries but is a severe problem in many developing countries, where sometimes water is only provided for a few hours every day or a few days a week; that is, it is intermittent. This is especially problematic for informal settlements, which are often poorly connected to the water supply network and have no means of procuring alternative sources such as private boreholes. It is estimated that about half of the population of developing countries receives water on an intermittent basis.
Water quality
Drinking water quality has a micro-biological and a physico-chemical dimension. There are thousands of parameters of water quality. In public water supply systems water should, at a minimum, be disinfected—most commonly through the use of chlorination or the use of ultraviolet light—or it may need to undergo treatment, especially in the case of surface water. Water quality is also dependent of the quality and level of pollution of the water source.
Water pressure
Water pressures vary in different locations of a distribution system. Water mains below the street may operate at higher pressures, with a pressure reducer located at each point where the water enters a building or a house. In poorly managed systems, water pressure can be so low as to result only in a trickle of water or so high that it leads to damage to plumbing fixtures and waste of water. Pressure in an urban water system is typically maintained either by a pressurised water tank serving an urban area, by pumping the water up into a water tower and relying on gravity to maintain a constant pressure in the system or solely by pumps at the water treatment plant and repeater pumping stations.
Typical UK pressures are 4–5 bar (60–70 PSI) for an urban supply. However, some people can get over eight bars or below one bar. A single iron main pipe may cross a deep valley, it will have the same nominal pressure, however each consumer will get a bit more or less because of the hydrostatic pressure (about 1 bar/10 m height). So people at the bottom of a hill will get about 3 bars more than those at the top.
The effective pressure also varies because of the pressure loss due to supply resistance, even for the same static pressure. An urban consumer may have 5 metres of 15-mm pipe running from the iron main, so the kitchen tap flow will be fairly unrestricted. A rural consumer may have a kilometre of rusted and limed 22-mm iron pipe, so their kitchen tap flow will be small.
For this reason, the UK domestic water system has traditionally (prior to 1989) employed a "cistern feed" system, where the incoming supply is connected to the kitchen sink and also a header/storage tank in the attic. Water can dribble into this tank through a 12 mm pipe, plus ball valve, and then supply the house on 22 or 28 mm pipes. Gravity water has a small pressure (say bar in the bathroom) so needs wide pipes to allow for higher flows. This is fine for baths and toilets but is frequently inadequate for showers. A booster pump or a hydrophore is installed to increase and maintain pressure. For this reason urban houses are increasingly using mains pressure boilers ("combies") which take a long time to fill a bath but suit the high back pressure of a shower.
Institutional responsibility and governance
A great variety of institutions have responsibilities in water supply. A basic distinction is between institutions responsible for policy and regulation on the one hand; and institutions in charge of providing services on the other hand.
Policy and regulation
Water supply policies and regulation are usually defined by one or several Ministries, in consultation with the legislative branch. In the United States the United States Environmental Protection Agency, whose administrator reports directly to the President, is responsible for water and sanitation policy and standard setting within the executive branch. In other countries responsibility for sector policy is entrusted to a Ministry of Environment (such as in Mexico and Colombia), to a Ministry of Health (such as in Panama, Honduras and Uruguay), a Ministry of Public Works (such as in Ecuador and Haiti), a Ministry of Economy (such as in German states) or a Ministry of Energy (such as in Iran). A few countries, such as Jordan and Bolivia, even have a Ministry of Water. Often several Ministries share responsibilities for water supply.
In the European Union, important policy functions have been entrusted to the supranational level. Policy and regulatory functions include the setting of tariff rules and the approval of tariff increases; setting, monitoring and enforcing norms for quality of service and environmental protection; benchmarking the performance of service providers; and reforms in the structure of institutions responsible for service provision. The distinction between policy functions and regulatory functions is not always clear-cut. In some countries they are both entrusted to Ministries, but in others regulatory functions are entrusted to agencies that are separate from Ministries.
Regulatory agencies
Dozens of countries around the world have established regulatory agencies for infrastructure services, including often water supply and sanitation, in order to better protect consumers and to improve efficiency. Regulatory agencies can be entrusted with a variety of responsibilities, including in particular the approval of tariff increases and the management of sector information systems, including benchmarking systems. Sometimes they also have a mandate to settle complaints by consumers that have not been dealt with satisfactorily by service providers. These specialized entities are expected to be more competent and objective in regulating service providers than departments of government Ministries. Regulatory agencies are supposed to be autonomous from the executive branch of government, but in many countries have often not been able to exercise a great degree of autonomy.
In the United States regulatory agencies for utilities have existed for almost a century at the level of states, and in Canada at the level of provinces. In both countries they cover several infrastructure sectors. In many U.S. states they are called Public Utility Commissions. For England and Wales, a regulatory agency for water (OFWAT) was created as part of the privatization of the water industry in 1989. In many developing countries, water regulatory agencies were created during the 1990s in parallel with efforts at increasing private sector participation. (for more details on regulatory agencies in Latin America, for example, please see Water and sanitation in Latin America and the regional association of water regulatory agencies ADERASA.)
Many countries do not have regulatory agencies for water. In these countries service providers are regulated directly by local government, or the national government. This is, for example, the case in the countries of continental Europe, in China and India.
Service provision
Water supply service providers, which are often utilities, differ from each other in terms of their geographical coverage relative to administrative boundaries; their sectoral coverage; their ownership structure; and their governance arrangements.
Geographical coverage
Many water utilities provide services in a single city, town or municipality. However, in many countries municipalities have associated in regional or inter-municipal or multi-jurisdictional utilities to benefit from economies of scale. In the United States these can take the form of special-purpose districts which may have independent taxing authority. An example of a multi-jurisdictional water utility in the United States is WASA, a utility serving Washington, D.C. and various localities in the state of Maryland. Multi-jurisdictional utilities are also common in Germany, where they are known as "Zweckverbaende", in France and in Italy.
In some federal countries, there are water service providers covering most or all cities and towns in an entire state, such as in all states of Brazil and some states in Mexico (see Water supply and sanitation in Mexico). In England and Wales, water supply and sewerage is supplied almost entirely through ten regional companies. Some smaller countries, especially developed countries, have established service providers that cover the entire country or at least most of its cities and major towns. Such national service providers are especially prevalent in West Africa and Central America, but also exist, for example, in Tunisia, Jordan and Uruguay (see also water supply and sanitation in Uruguay). In rural areas, where about half the world population lives, water services are often not provided by utilities, but by community-based organizations which usually cover one or sometimes several villages.
Sector coverage
Some water utilities provide only water supply services, while sewerage is under the responsibility of a different entity. This is for example the case in Tunisia. However, in most cases water utilities also provide sewer and sewage treatment services. In some cities or countries utilities also distribute electricity. In a few cases such multi-utilities also collect solid waste and provide local telephone services. An example of such an integrated utility can be found in the Colombian city of Medellín. Utilities that provide water, sanitation and electricity can be found in Frankfurt, Germany (Mainova), in Casablanca, Morocco and in Gabon in West Africa. Multi-utilities provide certain benefits such as common billing and the option to cross-subsidize water services with revenues from electricity sales, if permitted by law.
Ownership and governance arrangements
Water supply providers can be either public, private, mixed or cooperative. Most urban water supply services around the world are provided by public entities. As Willem-Alexander, Prince of Orange (2002) stated, "The water crisis that is affecting so many people is mainly a crisis of governance—not of water scarcity." The introduction of cost-reflective tariffs together with cross-subsidization between richer and poorer consumers is an essential governance reform in order to reduce the high levels of Unaccounted-for Water (UAW) and to provide the finance needed to extend the network to those poorest households who remain unconnected. Partnership arrangements between the public and private sector can play an important role in order to achieve this objective.
Private sector participation
An estimated 10 percent of urban water supply is provided by private or mixed public-private companies, usually under concessions, leases or management contracts. Under these water service contract arrangements the public entity that is legally responsible for service provision delegates certain or all aspects of service provision to the private service provider for a period typically ranging from 4 to 30 years. The public entity continues to own the assets. These arrangements are common in France and in Spain. Only in few parts of the world water supply systems have been completely sold to the private sector (privatization), such as in England and Wales as well as in Chile. The largest private water companies in the world are Suez and Veolia Environnement from France; Aguas de Barcelona from Spain; and Thames Water from the UK, all of which are engaged internationally (see links to website of these companies below). In recent years, a number of cities have reverted to the public sector in a process called "remunicipalization".
Public water service provision
90% of urban water supply and sanitation services are currently in the public sector. They are owned by the state or local authorities, or also by collectives or cooperatives. They run without an aim for profit but are based on the ethos of providing a common good considered to be of public interest. In most middle and low-income countries, these publicly owned and managed water providers can be inefficient as a result of political interference, leading to over-staffing and low labor productivity.
Ironically, the main losers from this institutional arrangement are the urban poor in these countries. Because they are not connected to the water supply network, they end up paying far more per liter of water than do more well-off households connected to the network who benefit from the implicit subsidies that they receive from loss-making utilities.
The fact that we are still so far from achieving universal access to clean water and sanitation shows that public water authorities, in their current state, are not working well enough.
Yet some are being very successful and are modelling the best forms of public management. As Ryutaro Hashimoto, former Japanese Prime Minister, notes: "Public water services currently provide more than 90 percent of water supply in the world. Modest improvement in public water operators will have immense impact on global provision of services."
Governance arrangements
Governance arrangements for both public and private utilities can take many forms (Kurian and McCarney, 2010). Governance arrangements define the relationship between the service provider, its owners, its customers and regulatory entities. They determine the financial autonomy of the service provider and thus its ability to maintain its assets, expand services, attract and retain qualified staff, and ultimately to provide high-quality services. Key aspects of governance arrangements are the extent to which the entity in charge of providing services is insulated from arbitrary political intervention; and whether there is an explicit mandate and political will to allow the service provider to recover all or at least most of its costs through tariffs and retain these revenues. If water supply is the responsibility of a department that is integrated in the administration of a city, town or municipality, there is a risk that tariff revenues are diverted for other purposes. In some cases, there is also a risk that staff are appointed mainly on political grounds rather than based on their professional credentials.
Standardization
International standards for water supply system are covered by International Classification of Standards (ICS) 91.140.60.
Comparing the performance of water and sanitation service providers
Comparing the performance of water and sanitation service providers (utilities) is needed, because the sector offers limited scope for direct competition (natural monopoly). Firms operating in competitive markets are under constant pressure to out perform each other. Water utilities are often sheltered from this pressure, and it frequently shows: some utilities are on a sustained improvement track, but many others keep falling further behind best practice. Benchmarking the performance of utilities allows the stimulation of competition, establish realistic targets for improvement and create pressure to catch up with better utilities. Information on benchmarks for water and sanitation utilities is provided by the International Benchmarking Network for Water and Sanitation Utilities.
Financial aspects
Costs and financing
The cost of supplying water consists, to a very large extent, of fixed costs (capital costs and personnel costs) and only to a small extent of variable costs that depend on the amount of water consumed (mainly energy and chemicals). The full cost of supplying water in urban areas in developed countries is about US$1–2 per cubic meter depending on local costs and local water consumption levels. The cost of sanitation (sewerage and wastewater treatment) is another US$1–2 per cubic meter. These costs are somewhat lower in developing countries. Throughout the world, only part of these costs is usually billed to consumers, the remainder being financed through direct or indirect subsidies from local, regional or national governments (see section on tariffs).
Besides subsidies water supply investments are financed through internally generated revenues as well as through debt. Debt financing can take the form of credits from commercial Banks, credits from international financial institutions such as the World Bank and regional development banks (in the case of developing countries), and bonds (in the case of some developed countries and some upper middle-income countries).
Tariffs
Almost all service providers in the world charge tariffs to recover part of their costs. According to estimates by the World Bank the average (mean) global water tariff is US$0.53 per cubic meter. In developed countries the average tariff is US$1.04, while it is only U$0.11 in the poorest developing countries. The lowest tariffs in developing countries are found in South Asia (mean of US$0.09/m3), while the highest are found in Latin America (US$0.41/m3). Data for 132 cities were assessed. The tariff is estimate for a consumption level of 15 cubic meters per month. Few utilities do recover all their costs. According to the same World Bank study only 30% of utilities globally, and only 50% of utilities in developed countries, generate sufficient revenue to cover operation, maintenance and partial capital costs.
According to another study undertaken in 2006 by NUS Consulting, the average water and sewerage tariff in 14 mainly OECD countries excluding VAT varied between US$0.66 per cubic meter in the United States and the equivalent of US$2.25 per cubic meter in Denmark. However, water consumption is much higher in the US than in Europe. Therefore, residential water bills may be very similar, even if the tariff per unit of consumption tends to be higher in Europe than in the US.
A typical family on the US East Coast paid between US$30 and US$70 per month for water and sewer services in 2005.
In developing countries, tariffs are usually much further from covering costs. Residential water bills for a typical consumption of 15 cubic meters per month vary between less than US$1 and US$12 per month.
Water and sanitation tariffs, which are almost always billed together, can take many different forms. Where meters are installed, tariffs are typically volumetric (per usage), sometimes combined with a small monthly fixed charge. In the absence of meters, flat or fixed rates—which are independent of actual consumption—are being charged. In developed countries, tariffs are usually the same for different categories of users and for different levels of consumption.
In developing countries, the situation is often characterized by cross-subsidies with the intent to make water more affordable for residential low-volume users that are assumed to be poor. For example, industrial and commercial users are often charged higher tariffs than public or residential users. Also, metered users are often charged higher tariffs for higher levels of consumption (increasing-block tariffs). However, cross-subsidies between residential users do not always reach their objective. Given the overall low level of water tariffs in developing countries even at higher levels of consumption, most consumption subsidies benefit the wealthier segments of society. Also, high industrial and commercial tariffs can provide an incentive for these users to supply water from other sources than the utility (own wells, water tankers) and thus actually erode the utility's revenue base.
Investments needed in developing countries
Water supply and sanitation require a huge amount of capital investment in infrastructure such as pipe networks, pumping stations and water treatment works. It is estimated that in developing countries investments of at least US$200 billion have to be made per year to replace aging water infrastructure to guarantee supply, reduce leakage rates and protect water quality.
International attention has focused upon the needs of developing countries. To meet the Millennium Development Goals targets of halving the proportion of the population lacking access to safe drinking water and basic sanitation by 2015, current annual investment on the order of US$10 to US$15 billion would need to be roughly doubled. This does not include investments required for the maintenance of existing infrastructure.
Once infrastructure is in place, operating water supply and sanitation systems entails significant ongoing costs to cover personnel, energy, chemicals, maintenance and other expenses. The sources of money to meet these capital and operational costs are essentially either user fees, public funds or some combination of the two. It is also important to consider is the flexibility of the water supply system.
Metering
Metering of water supply is usually motivated by one or several of four objectives. First, it provides an incentive to conserve water which protects water resources (environmental objective). Second, it can postpone costly system expansion and saves energy and chemical costs (economic objective). Third, it allows a utility to better locate distribution losses (technical objective). Fourth, it allows suppliers to charge for water based on use, which is perceived by many as the fairest way to allocate the costs of water supply to users. Metering is considered good practice in water supply and is widespread in developed countries, except for the United Kingdom. In developing countries it is estimated that half of all urban water supply systems are metered and the tendency is increasing.
Water meters are read by one of several methods:
the water customer writes down the meter reading and mails in a postcard with this info to the water department;
the water customer writes down the meter reading and uses a phone dial-in system to transfer this info to the water department;
the water customer logs into the website of the water supply company, enters the address, meter ID and meter readings
a meter reader comes to the premises and enters the meter reading into a handheld computer;
the meter reading is echoed on a display unit mounted to the outside of the premises, where a meter reader records them;
a small radio is hooked up to the meter to automatically transmit readings to corresponding receivers in handheld computers, utility vehicles or distributed collectors
a small computer is hooked up to the meter that can either dial out or receive automated phone calls that give the reading to a central computer system.
Most cities are increasingly installing automatic meter reading (AMR) systems to prevent fraud, to lower ever-increasing labor and liability costs and to improve customer service and satisfaction.
Global access
History
Throughout history, people have devised systems to make getting and using water more convenient. Living in semi-arid regions, ancient Persians in the 1st millennium BC used qanat system to gain access to water in the mountains. Early Rome had indoor plumbing, meaning a system of aqueducts and pipes that terminated in homes and at public wells and fountains for people to use.
Until the Enlightenment era, little progress was made in water supply and sanitation and the engineering skills of the Romans were largely neglected throughout Europe. It was in the 18th century that a rapidly growing population fueled a boom in the establishment of private water supply networks in London. London water supply infrastructure developed over many centuries from early mediaeval conduits, through major 19th-century treatment works built in response to cholera threats, to modern, large-scale reservoirs. The first screw-down water tap was patented in 1845 by Guest and Chrimes, a brass foundry in Rotherham.
The first documented use of sand filters to purify the water supply dates to 1804, when the owner of a bleachery in Paisley, Scotland, John Gibb, installed an experimental filter, selling his unwanted surplus to the public. The first treated public water supply in the world was installed by engineer James Simpson for the Chelsea Waterworks Company in London in 1829. The practice of water treatment soon became mainstream, and the virtues of the system were made starkly apparent after the investigations of the physician John Snow during the 1854 Broad Street cholera outbreak demonstrated the role of the water supply in spreading the cholera epidemic.
By country
See also
Human right to water and sanitation
Nonresidential water use in the U.S.
Residential water use in the U.S. and Canada
Water efficiency
Water resources
Water scarcity
Water security
Water supply terrorism
References
External links
The World Bank on private water operations in rural communities
The World Bank on water utility subsidies
The WHO's site on water
The OECD's site on water
Water management | Water supply | Chemistry,Engineering,Environmental_science | 5,176 |
57,309,176 | https://en.wikipedia.org/wiki/NGC%203307 | NGC 3307 is a lenticular galaxy located about 185 million light-years away in the constellation Hydra. The galaxy was discovered by astronomer John Herschel on March 22, 1836 and is a member of the Hydra Cluster.
See also
List of NGC objects (3001–4000)
References
External links
Hydra Cluster
Hydra (constellation)
Barred spiral galaxies
3307
31430
Astronomical objects discovered in 1836
Discoveries by John Herschel | NGC 3307 | Astronomy | 84 |
11,018,045 | https://en.wikipedia.org/wiki/249th%20Engineer%20Battalion%20%28United%20States%29 | The 249th Engineer Battalion (United States) is a versatile power generation battalion assigned to the U.S. Army Corps of Engineers that provides commercial-level power to military units and federal relief organizations during full-spectrum operations. Additionally, the commander serves as the Commandant of the U.S. Army Prime Power School, the institution responsible for the development of Army and Navy power generation specialists.
Motto
The battalion's motto is "Build, Support, Sustain!".
Units
Headquarters and Headquarters Company – Fort Belvoir, Virginia
Heavy Maintenance Section – Fort Belvoir, Virginia
A Company – Schofield Barracks, Hawaii
B Company – Fort Liberty, North Carolina
C Company – Fort Belvoir, Virginia
D Company – (USAR) – Providence, Rhode Island
1st Platoon – Cranston, Rhode Island
2nd Platoon – Cranston, Rhode Island
3rd Platoon – Cranston, Rhode Island
4th Platoon – Fort Belvoir, Virginia
U.S. Army Prime Power School – Fort Leonard Wood, Missouri.
Mission
On order, deploy worldwide to provide prime electrical power and electrical systems expertise in support of military operations and the National Response Framework.
The 249th Engineer Battalion also supports other missions:
Operation Enduring Freedom
Operation Iraqi Freedom
THAAD Power Support
JLENS Power Support
Intelligence and Security Command (INSCOM) (Korea generator maintenance)
Operation Bright Star (Egypt)
Chinhae generator maintenance
Limited Installation support missions
Task Force SAFE
U.S. Army Corps of Engineers support to presidentially declared disasters
History
As a combat engineer battalion
World War II
The 249th Engineer Combat Battalion was constituted on 5 May 1943 at Camp Bowie, Texas. The battalion was organized and under the command of only three captains. The other officers that were supplied to the unit were second lieutenants from the 1943 class of West Point. Shortly after, the battalion participated in two maneuvers in Louisiana, known as the "Louisiana Maneuvers"; there the battalion and its soldiers learned valuable lessons for war.
The 249th sailed from the United States to England in May 1944, after equipping and preparing for combat, the Unit landed on Utah Beach in August 1944 under the 1137th Engineer Combat Group commanded by Colonel George A. Morris. In October through November 1944, the soldiers were specially trained on using the Bailey bridge in Trier, France.
Later that year on 18 December 1944, the Black Lions were ordered to move from the Saar River, where the unit was building a bridge, to the Ardennes, commonly called the Battle of the Bulge. Upon arriving to the front, the 249th was assigned to the 26th Infantry Division, already engaged and in defensive positions along the southeast corner of the Bulge. The battalion was used in an effort to block the German advance by deploying landmines, obstacles and establishing roadblocks.
On 24 December 1944, Brigadier General Harlan Harkness, the assistant division commander, ordered the battalion to advance and secure the towns of Arsdorf and Bigonville to the north of the 26th Infantry Division, near the area of operations of the 4th Armored Division, in order to relieve the occupied towns so the division could advance and attack the enemy line. Companies A and C were ordered into the town of Arsdorf where the battalion was engaged in fierce combat for two days. It was later learned that the town had never been secured by the 4th Armored Division.
In February 1945, the battalion was selected for the special task of crossing the Rhine River. On 19 March 1945, the unit was assigned to the engineer task force charged with crossing the Rhine at Oppenheim. The main thrust of the effort was to use assault boats to get troops from 5th Infantry Division across and later to construct a more stable pontoon bridge. The battalion met little resistance across the river and quickly began constructing the bridge. After an accident resulting in a raft being sunk, the Battalion moved downriver to Mainz. After this bridge site was secure, the 249th was detached from the 1137th Engineer Group and was given the mission to secure and maintain the bridges on the Rhine River. In May 1945, when the war ended in Europe, the battalion was moved to Plattling, Germany where they built a camp for displaced refugees. In November 1945, the 249th Engineers were sent on their final orders to Camp Lucky Strike, near Marseilles, France and then redeployed back to the United States. The division was inactivated at Camp Patrick Henry, Virginia on 27 November 1945.
Post World War II
In late 1954, the Black Lion Battalion was withdrawn from the Reserves and assigned to the Regular Army. In February 1955, it was activated and assigned to USAREUR and an Engineer Battalion (Combat Heavy). From 1955 until 1960, the 249th Engineer Battalion (Construction) was stationed at Kleber Kaserne, ((Kaiserslautern, Germany)). Then it was dispatched to Etain, France for a time. Then the battalion was stationed at Gerszewski Barracks, Knielingen, Karlsruhe, Germany, under the command of the 18th Engineer Brigade, where it provided construction support to USAREUR elements stationed in Germany for the Cold War.
As a prime power battalion
In 1994, the battalion was reactivated and designated as the 249th Engineer Battalion (Prime Power), stationed at Fort Belvoir, VA.
9/11
Immediately after the attacks on the World Trade Center on 11 September 2001, elements of the 249th were deployed to New York City and were instrumental in restoring power to Wall Street enabling the financial district to resume operations within a week of the attack.
Global War on Terrorism
The 249th Engineer Battalion (Prime Power) provides oversight on all coalition operating base power projects in Iraq (Operation Iraqi Freedom) and Afghanistan (Operation Enduring Freedom).
Hurricane Katrina
The 249th deployed teams to the Gulf Region under Joint Task Force Katrina, working with contractors, and local and state entities to assess, they helped install and maintain emergency generators at critical facilities. By 5 September 2005, the 17th Street Canal breach was closed. Blackhawk and Chinook helicopters had dropped over 200 sand bags, with approximately 125 sandbags breaking the surface of the water. After the emergency was over, plans called for the canal to be drained and the wall repaired.
There were three 42" mobile pumps staged and two 42" and two 30" pumps were placed at the sheet pile closure. Sewer & water board, electric utility and the 249th Engineer Battalion (Prime Power) were completing pump house inspection. When the pumps began operation, a 40-foot-wide opening was made in the sheet piling to allow water to flow out of the canal.
Worldwide
Through the United States Army Corps of Engineers, the 249th soldiers provide contracting officer technical representation on projects throughout the world.
Lineage
Constituted 25 February 1943 in the Army of the United States as the 249th Engineer Combat Battalion
Activated 5 May 1943 at Camp Bowie, Texas
Inactivated 28 November 1945 at Camp Patrick Henry, Virginia
Redesignated 23 March 1948 as the 442d Engineer Construction Battalion and allotted to the Organized Reserves
Activated 8 April 1948 with headquarters at Ames, Iowa
(Organized Reserves redesignated 25 March 1948 as the Organized Reserve Corps; redesignated 9 July 1952 as the Army Reserve)
Inactivated 22 May 1950 at Ames and Council Bluffs, Iowa
Redesignated 25 June 1952 as the 249th Engineer Construction Battalion
Redesignated 9 December 1954 as the 249th Engineer Battalion; concurrently withdrawn from the Army Reserve and allotted to the Regular Army
Activated 9 February 1955 in Germany
Inactivated 15 October 1991 in Germany
Activated 16 November 1994 at Fort Belvoir, Virginia
Honors
Campaign participation credit
World War II
Northern France
Rhineland
Ardennes-Alsace
Central Europe
Southwest Asia
Defense of Saudi Arabia
Liberation and Defense of Kuwait
Cease-Fire
Decorations
Cited in the Order of the Day of the Belgian Army for actions in the Ardennes
Meritorious Unit Commendation (Army) for SOUTHWEST ASIA 1990–1991
Army Superior Unit Award for 25 Aug 92 – 28 Oct 92
Army Superior Unit Award for 1994–1995
Army Superior Unit Award for 1995–1996
Army Superior Unit Award for 2005 (Hurricanes Katrina, Rita, & Wilma)
Army Superior Unit Award for 2011-2012
See also
United States Army Corps of Engineers
Civil engineering and infrastructure repair in New Orleans after Hurricane Katrina
Army Nuclear Power Program
References
External links
Official 249th Engineer Battalion website
Official U.S. Army Prime Power School website
Description of the Coat of Arms and Distinctive Unit Insignia
Bridge to the Past: 249th Engineer Battalion from Combat to Prime Power by COL John K. Addison, Retired
Prime-Power Considerations for Engineer Planners, by Captain Geoff Van Epps
Reflections on Building Great Engineers, COL Paul B. Olsen
249
Military units and formations established in 1943
249
United States Army Corps of Engineers | 249th Engineer Battalion (United States) | Engineering | 1,738 |
720,834 | https://en.wikipedia.org/wiki/IDF%20Caterpillar%20D9 | The IDF Caterpillar D9 — nicknamed Doobi (, for teddy bear) — is a Caterpillar D9 armored bulldozer used by the Israel Defense Forces (IDF). It is supplied by Caterpillar Inc. and modified by the Israel Defense Forces, Israeli Military Industries and Israel Aerospace Industries to increase the survivability of the bulldozer in hostile environments and enable it to withstand attack.
In the 1980s the IDF began modifying D9 bulldozers to incorporate armour. The bulldozers can also be fitted with weaponry: machine guns and grenade launchers. There are various models, including a remote controlled version.
Over the course of numerous campaigns, IDF bulldozers have been used to demolish thousands of Palestinian homes in Gaza, leaving tens of thousands of people homeless. The Office of the UN High Commissioner on Human Rights has advised Caterpillar Inc. that by supplying the bulldozers to the IDF it may be complicit in human rights violations.
The IDF Caterpillar D9 is operated by the Israel Defense Forces (IDF) Combat Engineering Corps essentially for combat engineering operations. It has been involved in incidents of civilian deaths, including the 2003 killing of activist Rachel Corrie and civilians sheltering outside the Kamal Adwan Hospital reported in 2023 and 2024 during the 2023 Israel–Hamas war.
Characteristics
The D9R, the latest generation of Caterpillar D9 bulldozers in IDF service, has a power of and drawbar pull of 71.6 metric tons (about 702 kN). Older generations, such as D9L and D9N are still in service, mainly in the reserve forces. The D9 has a crew of two: operator and commander. It is operated by the TZAMA (In = ציוד מכני הנדסי, mechanical engineering equipment) units of the Combat Engineering Corps.
In some cases the bulldozers have been fitted with machine guns and grenade launchers.
The IDF uses the D9 for a wide variety of combat engineering tasks, such as earthworks, digging moats, mounting sand barriers, building fortifications, rescuing stuck, overturned or damaged armored fighting vehicles (along with the M88 Recovery Vehicle), clearing land mines, detonating IEDs and explosives, handling booby traps, clearing terrain obstacles and opening routes to armored fighting vehicles and infantry, as well as structures demolition, including under fire.
History
Caterpillar Inc. introduced the Caterpillar D9 bulldozer in 1954 and it quickly found its way to civilian engineering in Israel and from there it was recruited to military service by the Israel Defense Forces (IDF).
Earlier use
Unarmored D9 bulldozers were used in the Sinai War (1956), Six-Day War (1967), Yom Kippur War (1973) and the 1982 Lebanon War (1982).
During the 1982 Lebanon War D9s were employed in breaching and paving ways through mountains and fields in the mountain landscape of southern Lebanon. The D9s also cleared minefields and explosive belly charges set on the main routes by Syrian army and Palestinian insurgents. Because the D9 served as front-line tools, the IDF developed armor kits to protect the lives of the soldiers operating them.
The Second Intifada
Armored D9 bulldozers were used during the Second Intifada (2000–2005), a Palestinian uprising against Israeli occupation. They were used to open safe routes to IDF forces and detonate explosive charges planted by Palestinian militants. The bulldozers were used extensively to clear shrubbery and structures which were used as cover for Palestinian attacks. In addition they razed houses of families of suicide bombers.
Over 3,000 homes in Palestine were demolished by Israel during the conflict, leaving tens of thousands of people homeless. The destruction of Palestinian homes promoted protests. In one such protest in Rafah in 2003 a group of eight people tried to stop a D9 bulldozer from demolishing a family home. The operator of the bulldozer drove over one of the protesters, Rachel Corrie. She died as a result of her injuries.
Following several incidents where armed Palestinians barricaded themselves inside houses and killed soldiers attempting to breach the entries, the IDF developed "Nohal Sir Lachatz" (נוהל סיר לחץ "pressure cooker procedure") in which D9s and other engineering vehicles were used to bring them out by razing the houses; most of them surrendered because of fear of being buried alive.
During the 2002 Battle of Jenin armored D9 bulldozers cleared booby traps and improvised explosive devices, and eventually razed houses from which militants fired upon Israeli soldiers or contained possible IEDs and booby traps. A translated interview with one of the drivers was published by Gush Shalom. After the deadly ambush in which 13 soldiers were killed, D9 bulldozers razed the center of the Jenin refugee camp and forced the remaining Palestinian fighters to surrender, thus finishing the battle with an Israeli victory.
D9R and early 21st century
During the early 2000s, the new D9R entered IDF service, equipped with a new generation armor designed by the IDF's MASHA (, lit. Restoration and Maintenance Center), Israel Aerospace Industries and Zoko Shiloovim/ITE (Caterpillar Inc. importers in Israel). Due to the increasing threat of shaped charge anti-tank rockets and anti-tank missile, the IDF introduced in 2005 a slat armor, installed in large numbers on the IDF D9R dozers in 2006. The slat armor proved to be effective and life-saving; its developers and installers won the IDF's Ground Command award.
The IDF also operates armored remote-controlled D9N bulldozers, called "Raam HaShachar" (, lit. "thunder of dawn") often incorrectly referred as "black thunder". The remote-controlled bulldozer has been used to clear mines. They were used in the Second Lebanon War in 2006 and the Gaza War (2008–2009).
Armored D9R bulldozers took part in the effort to extinguish 2010 Mount Carmel forest fire. The armored bulldozers opened routes to fire trucks and fire fighters into the heart of the fire. They also created fire breaks by clearing shrubbery and pushing up soil barriers in order to prevent the fire from spreading. They also helped extinguish fires by burying them in dirt and soil.
Gaza War (2008–2009)
In total, 100 D9s were deployed during the Gaza War (2008–2009), dubbed 'Operation Cast Lead' by Israel. The war led to extensive destruction in Gaza, especially of Palestinian homes; Israeli bulldozers and anti-tank mines were commonly used. According to Amnesty International:
In March 2009, The Jerusalem Post reported that the IDF intended to increase its use of unmanned D9 bulldozers, doubling the number it had. The following year Israel's Channel 2 reported that Caterpillar would delay the delivery of D9 bulldozers to the IDF while an investigation into the killing of Rachel Corrie took place.
2014 Gaza War
IDF D9 armored bulldozers took major role in the 2014 Gaza War, both in defensive missions and offensive maneuvers. The D9s assisted other heavy equipment such as excavators and drillers in exposing and destroying cross-border underground tunnels penetrating into Israel, more than 30 of these tunnels were destroyed during the operation. The reserve mechanical engineering equipment (צמ"ה) and bulldozers battalion of the Central Command received a citation of recommendation (צל"ש, tzalash) from the Chief of Staff of the Israel Defense Forces.
D9s participated in the ground offensive, opening routes to tanks and infantry forces, and demolishing structures that were used by Palestinian militants. On July 27, one D9 was hit by an anti-tank missile, killing its operator and wounding its commander. Another D9 demolished the building from which the missile was launched, killing 8 militants and capturing two more. The crew received a citation of recommendation (צל"ש, tzalash) for their action.
D9T Panda
In 2018 the Israel Defense Forces Combat Engineering Corps started to deploy and operate the "Panda" – a remote-controlled version of an armored Caterpillar D9T bulldozer. In 2018, Israel Aerospace Industries announced that it had signed a contract to equip the IDF with more D9T Panda dozers. In 2022-2023 the Panda entered regular service with the IDF.
In 2019, Elbit Systems was awarded an IMOD contract to install the Iron Fist active protection system on the IDF's armored D9 bulldozers, to give them extra protection from anti-tank missiles.
Israel–Hamas war
During the Israel–Hamas war D9 Bulldozers were deployed on the ground offensive into Gaza where it was used to clear routes for ground forces to manoeuvre and expose shafts of Hamas combat tunnels. According to The Independent around 100 D9 bulldozers were expected to be used in the opening stage of the war. On 16 December the IDF captured the Kamal Adwan Hospital; in doing so IDF bulldozers crushed people who had been sheltering outside the hospital.
An investigation by CNN published in January 2024 used satellite imagery to identify sixteen burial grounds in Gaza that had been desecrated by the IDF using bulldozers to level cemeteries and dig up bodies. Later that month Ynet reported that the IDF would buy a further 100 bulldozers. A shipment of 134 bulldozers had not arrived by November. Bulldozers were also used in the deliberate destruction of Gaza's environment, with an estimated 38–48% of Gaza's farmland and tree cover destroyed by Israel's military. Norwegian pension fund Kommunal Landspensjonskasse stopped investing in Caterpillar due to the use of its products by the IDF.
Models in IDF service
Criticism
Caterpillar's sales of D9 bulldozers to the Israeli military for use in the occupied Palestinian territories has long drawn criticism from human rights groups, society groups and responsible investment monitors.
Amnesty International released a report in May 2004 on home demolition in the occupied Palestinian territories in May 2004 that noted the risk of complicity for Caterpillar in human rights violations. The Office of the UN High Commissioner on Human Rights sent a letter to the company the next month warning that by selling bulldozers to the IDF Caterpillar may be complicit in human rights violations, specifically the right to food as the bulldozers were used to destroy Palestinian farms. Human Rights Watch reported the same year on the systematic use of D9 bulldozers in illegal demolitions throughout the occupied territories and called on Caterpillar to suspend its sales to Israel, citing the company's own code of conduct.
The punitive destruction of Palestinian homes has been described as a form of collective punishment, and in the view of Human Rights Watch may be considered a war crime.
The pro-Palestinian group Jewish Voice for Peace and four Roman Catholic orders of nuns planned to introduce a resolution at a Caterpillar shareholder meeting subsequent to the human rights reports asking for an investigation into whether Israel's use of the company's bulldozer to destroy Palestinian homes conformed with the company's code of business conduct. In response, the pro-Israel advocacy group StandWithUs urged its members to buy Caterpillar stock and to write letters of support to the company.
The US investment indexer MSCI removed Caterpillar from three of its indexes for socially responsible investments in 2012, citing the Israeli military’s use of its bulldozers in the Palestinian territories. In 2017, documents emerged that showed Caterpillar had hired private investigators to spy on the family of Rachel Corrie, the American human rights activist who was killed by a D9 bulldozer in Rafah in early 2003. In 2022, the Palestinian non-governmental organization Stop the Wall called Caterpillar, alongside Hyundai Heavy Industries, JCB and Volvo Group, complicit in what they referred to as Israel's ethnic cleansing of the occupied Palestinian territories through the use of its equipment in the demolition of eight Palestinian villages in Masafer Yatta in the southern West Bank.
See also
Israeli demolition of Palestinian property
Israeli war crimes
Collective punishment
Mahmoud Tawalbe, head of the Palestinian Islamic Jihad, killed in the Battle of Jenin (2002) by an IDF D9
Rachel Corrie, an ISM activist killed by an IDF D9 while acting as a human shield
References
External links
Caterpillar D-Series Track-Type Tractors – Official Caterpillar website
Armoured D9R Dozer (of the IDF) – review im Army-Technology
D9 in Israel's Combat Engineering Corps website (Hebrew)
The Israel Defense Forces operate the most heavily armored bulldozer in the world, We Are The Mighty, October 2022
D9
D9
D9
Caterpillar Inc. vehicles
Military vehicles introduced in the 1950s | IDF Caterpillar D9 | Engineering | 2,670 |
60,556,859 | https://en.wikipedia.org/wiki/Dropout%20%28streaming%20service%29 | Dropout is an American comedy subscription streaming service run by the production company of the same name (formerly CollegeHumor), founded in September 2018. Dropout streams original programming, and does not run advertisements. Its content is mainly composed of live play, such as Dimension 20 hosted by Brennan Lee Mulligan, and improv comedy and panel shows like Game Changer and Make Some Noise, both hosted by Dropout owner Sam Reich. Dropout's series often feature a rotating cast of regular comedians and performers.
History
CollegeHumor
Originally founded in 1999 by Josh Abramson and Ricky Van Veen, then independent website CollegeHumor was acquired by holding media and entertainment company IAC. CollegeHumor's work originally only included editorial articles, but eventually expanded to include online video and development and production of TV shows. In 2013, the video production CollegeHumor team moved to Los Angeles to continue to create online and traditional video consisting of shows like Adam Ruins Everything and Hot Date as well as sketch and short-form comedy on its YouTube channel. However, ad revenue became increasingly scarce, with YouTube's unfavorable ad rates and an ongoing risk of CollegeHumor's content being demonetized on the platform, as well as Facebook's inflated viewership numbers not bringing in anticipated ad sales.
After starting production in 2017, CollegeHumor launched its Dropout TV video platform on September26, 2018. CollegeHumor's then-CEO, Rich Cusick, announced the service as a "TV-MA version of CollegeHumor" that would "allow us to double down our investment into premium original content, resulting in a bigger, better, badder CollegeHumor." Dropout was also pitched as a way to allow fans to dive deeper into pre-established popular characters and shows from CollegeHumor's YouTube channel. CollegeHumor's Chief Creative Officer, Sam Reich, also claimed that the founding of Dropout was in response to difficulty in receiving advertising dollars on traditional media platforms for mature content. At launch, Dropout announced a mix of scripted and unscripted content, as well as digital comics and chat-story content and a subscriber-only Discord.
Dropout utilizes CollegeHumor spinoff Vimeo as its hosting service. Dropout officially launched native iOS and Android apps for its service in December 2018, allowing users to watch shows and also cast to smart TVs. Comics and chat stories were also integrated into the app.
Independent ownership
After launch, Dropout saw that the unscripted and less expensive content both acquired and retained viewers, while more expensive and scripted shows neither acquired nor retained viewers, with the limited exception of WTF 101. Dimension 20 became the most popular show on the platform, followed by Um, Actually and Cartoon Hell. Game Changer, hosted by Reich, would also become a success upon launch in 2019. A year after Dropout's launch, the service had between 75,000 and 100,000 subscribers. Dropout planned to release a new original title per month in 2019, according to Sam Reich. However, the programming slate did not allow Dropout to pivot quickly enough away from scripted content and it was still not profitable by the end of 2019; Reich later noted that "we had a writer's room full of scripted comedy writers. All of us were sort of having to pivot to think about something that wasn't our primary skill set." Because Dropout was in the middle of a $30million subscription investment, the streamer was on track to "lose" another $10million by the end of 2019 before it would be profitable.
In January of 2020, IAC announced it had ceased financing CollegeHumor, leading to the layoff of over 100 employees. IAC unsuccessfully attempted to sell CollegeHumor to numerous studios and entertainment companies at this time, reportedly seeking up to $100million for the company. However, IAC ultimately sold CollegeHumor to then Chief Creative Officer Reich in 2020, who then transitioned to CEO. IAC still has a minority stake in Dropout. The deal was finalized in March 2020. Dropout ended production on scripted shows and focused on unscripted shows such as Um, Actually, Dimension 20, and Game Changer, briefly producing these series through online conference during the beginning of the COVID-19 pandemic.
During the July-November 2023 SAG-AFTRA strike, Dropout series such as Dimension 20, Game Changer and Um, Actually were initially shut down. Reich stated:
In August 2023, Reich announced that all Dropout shows resumed production as it was determined that their "New Media Agreement for Non-Dramatic Programming" was actually a non-struck SAG-AFTRA contract.
Also in August 2023, NPR stated that "Dropout has not shared their official subscriber count, but Reich says it's in the mid-hundreds of thousands. He's very aware that doesn't come close to the hundreds of millions of subscribers that large media companies have, but, to him, that's not necessarily a problem.... Though they're not required to by unions, he said Dropout is working to become one of the first streamers to pay residuals to their writers, actors, and crew members". Dropout also pays performers to audition. Dropout's overall subscriber count almost doubled during 2023.
Dropout officially retired all CollegeHumor branding in September 2023. Later that year, Dropout shared its profit with its employees and other workers.
, Dropout earns around 8085% of its revenue via subscriptions.
Service and availability
Dropout is available worldwide; around 60% of subscribers were in the United States.
Subscription model
Dropout launched with a beta price of $3.99 per month, for the first three months of the service. After December 2018, the price rose to a three tiered option, with monthly memberships for $5.99/month, semi-annual memberships for $4.99/month, and annual memberships for $3.99/month. , new subscribers paid $5.99 monthly or $59.99 yearly, while those who already subscribed prior to that date were charged $4.99 monthly or $47.99 yearly. Users are also able to access Dropout content through YouTube via the join function. The company has justified the pricing model as allowing them to create content without being dependent on, or beholden to, requests from advertisers.
In December 2018, visitors to the service spent on average 31 minutes per visit, and visited on average 3.5 times per week. Throughout 2019, Dropout began to experiment with more live streaming versions of their shows, through using Twitch and podcast-like formats. At the end of 2023, the average user subscribed for 18 months; Reich said in June 2024 that the statistic is continuing to increase.
In August 2019, CollegeHumor also began to partner with Facebook to offer Dropout content via paid video subscriptions on Facebook's platform.
Services
In addition to original series, Dropout offered videos produced by CollegeHumor 72 hours before they were released to the public. Previously, a subscriber-only Discord server was included as a service, later expanded to non-subscribers as well, until its closure on May 26, 2024. Dropout also has a store which sells merchandise (such as shirts, stickers, and mugs) related to shows on the platform.
Cast members
Dropout productions often feature common rotating talent from a roster of performers, including:
Original shows
Shows on Dropout are usually released fortnightly, a schedule used more often for podcasts than for television.
Dropout planned to release a new original title per month in 2019, according to Sam Reich.
By 2020, the service had retired all scripted shows in favor of cheaper and more successful unscripted content.
Dirty Laundry, Play It By Ear, and Make Some Noise, each spun off from Game Changer, premiered throughout 2022. In 2023, Dropout started airing the improvisational interview show Very Important People, and in 2024 six new shows premiered: Smartypants, Thousandaires, Dropout Presents, Monét's Slumber Party, Gastronauts, and Nobody Asked.
Smartypants was renewed for a 15-episode second season in December 2024, to air in early 2025. A second season of Gastronauts is expected to film in March 2025.
Current and upcoming
Former
The following shows have concluded and are no longer producing new episodes.
Awards and nominations
Dropout's show Very Important People was the People's Voice Winner in the video comedy category at the 2024 Webby Awards.
References and notes
External links
Official website
CollegeHumor
IAC Inc.
Streaming media systems
Subscription video on demand services
2020 mergers and acquisitions | Dropout (streaming service) | Technology | 1,825 |
25,337,099 | https://en.wikipedia.org/wiki/Glazing%20jack | A glazing jack or glazing machine is a type of machine used for polishing leather. The machine consists of a solid glass cylinder, typically around in diameter and in length, mounted to the end of a rotating or reciprocating arm. The arm repeatedly and rapidly draws the glass across the surface of the leather, with significant downward pressure, as the operator moves the leather underneath the arm.
The repeated stroking of the leather smooths and compresses the surface and raises various color tones. Heat generated by friction during the glazing process can darken and harden the aniline finish of the leather, and can raise oils in the leather to the surface. Because no pigment is used, the porous structure of the leather remains visible, providing a depth to its appearance. The operator of the glazing jack can control the surface finish by varying the pressure of the tool and the number of strokes applied. Similarly to glazing, a copper or glass tool can be drawn across the leather by hand to create "sleeked" and "glassed" finishes, respectively.
Because jacking leather is a time-consuming and labor-intensive process, it is often reserved for more expensive or exotic leathers, such as reptile leathers.
See also
Surface finishing
References
Leather crafting
Machines | Glazing jack | Physics,Technology,Engineering | 266 |
21,977,771 | https://en.wikipedia.org/wiki/P-delta%20effect | In structural engineering, the P-Δ or P-delta effect refers to the abrupt changes in ground shear, overturning moment, and/or the axial force distribution at the base of a sufficiently tall structure or structural component when it is subject to a critical lateral displacement. A distinction can be made between P-delta effects on a multi-tiered building, written as P-Δ, and the effects on members deflecting within a tier, written as P-δ.
P-delta is a second-order effect on a structure which is loaded laterally. One first-order effect is the initial deflection of the structure in reaction to the lateral load. The magnitude of the P-delta effect depends on the magnitude of this initial deflection. P-delta is a moment found by multiplying the force due to the weight of the structure and applied axial load, P, by the first-order deflection, Δ or δ.
NUMERICAL EXAMPLE OF P DELTA EFFECT ON A CALCULATOR
You have a 1 meter tall rigid vertical rod that rotates on a hinge at the bottom of the rod. There is a 1 newton load on the top of the rod. The rod has a hinge with a rotational stiffness of 0.8 newton meters per radian of rotation.
So you input any initial rotational angle on the rod. The following table shows that the rod will iterate to 1.13 radians where the rod will be in stable equilibrium.
The formula for this table is next radians rotation=sin(last radians rotation)/.8 In the table from the formula you can see the rod starts at .1 radians and iterates to 1.13 radians where it is in stable equilibrium.
.1 .124 .156 .194 .241 .300 .367 .448 .542 .645 .751 .853 .942 1.01 1.06 1.09 1.11 1.12 1.12 1.13 1.13 and so on as it converges to 1.13 radians where the rod is stable. The P DELTA effect finds the stable final deformed shape of a structure just like how the rod rotates to a final deformed position at 1.13 radians. The idea is that iteratively repeated linear structural analyses can solve a non linear structural analysis problem. It takes multiple iterations of a linear analysis to compute the final deformed shape of a structure where the P DELTA effect is significant.
To illustrate the effect, consider a case in statics, a perfectly rigid body anchored on the ground subject to small lateral forces. In this example, a concentrated vertical load applied to the top of the structure and the weight of the structure itself are used to compute the ground reaction force and moment. Real structures are flexible and will bend to the side. The amount of bending is found through a strength of materials analysis. During this side displacement, the top has changed position and the structure is experiencing an additional moment, P×Δ, or near the middle, P×δ. This moment is not accounted for in a basic first-order analysis. By superposition, the structure responds to this moment by additional bending and displacement at the top.
In some sense, the P-delta effect is similar to the buckling load of an elastic, small-scale solid column given the boundary conditions of a free end on top and a completely restrained end at the bottom, with the exception that there may exist an invariant vertical load at the top of the column. A rod planted firmly into the ground, given a constant cross-section, can only extend so far up before it buckles under its own weight; in this case the lateral displacement for the solid is an infinitesimal quantity governed by Euler buckling. If the lateral displacement and/or the vertical axial loads through the structure are significant then a P-delta analysis should be performed to account for the non-linearities.
References
Lindeburg, M.R., Baradar, M. Seismic Design of Building Structures : A Professional's Introduction to Earthquake Forces and Design Details (8th ed.). Professional Publications, Inc. Belmont, CA (2001).
Comino, P. What is P-Delta Analysis? SkyCiv Engineering. Sydney, Australia (2016).
Statics | P-delta effect | Physics | 898 |
51,494,441 | https://en.wikipedia.org/wiki/NGC%20167 | NGC 167 is a spiral galaxy located approximately 172 million light-years from the Solar System in the constellation Cetus. It was discovered in 1886 by Francis Preserved Leavenworth.
See also
List of NGC objects (1–1000)
References
External links
SEDS
0167
2122
Cetus
Spiral galaxies
Discoveries by Francis Leavenworth | NGC 167 | Astronomy | 68 |
4,046,891 | https://en.wikipedia.org/wiki/Truncated%205-cell | In geometry, a truncated 5-cell is a uniform 4-polytope (4-dimensional uniform polytope) formed as the truncation of the regular 5-cell.
There are two degrees of truncations, including a bitruncation.
Truncated 5-cell
The truncated 5-cell, truncated pentachoron or truncated 4-simplex is bounded by 10 cells: 5 tetrahedra, and 5 truncated tetrahedra. Each vertex is surrounded by 3 truncated tetrahedra and one tetrahedron; the vertex figure is an elongated tetrahedron.
Construction
The truncated 5-cell may be constructed from the 5-cell by truncating its vertices at 1/3 of its edge length. This transforms the 5 tetrahedral cells into truncated tetrahedra, and introduces 5 new tetrahedral cells positioned near the original vertices.
Structure
The truncated tetrahedra are joined to each other at their hexagonal faces, and to the tetrahedra at their triangular faces.
Seen in a configuration matrix, all incidence counts between elements are shown. The diagonal f-vector numbers are derived through the Wythoff construction, dividing the full group order of a subgroup order by removing one mirror at a time.
Projections
The truncated tetrahedron-first Schlegel diagram projection of the truncated 5-cell into 3-dimensional space has the following structure:
The projection envelope is a truncated tetrahedron.
One of the truncated tetrahedral cells project onto the entire envelope.
One of the tetrahedral cells project onto a tetrahedron lying at the center of the envelope.
Four flattened tetrahedra are joined to the triangular faces of the envelope, and connected to the central tetrahedron via 4 radial edges. These are the images of the remaining 4 tetrahedral cells.
Between the central tetrahedron and the 4 hexagonal faces of the envelope are 4 irregular truncated tetrahedral volumes, which are the images of the 4 remaining truncated tetrahedral cells.
This layout of cells in projection is analogous to the layout of faces in the face-first projection of the truncated tetrahedron into 2-dimensional space. The truncated 5-cell is the 4-dimensional analogue of the truncated tetrahedron.
Images
Alternate names
Truncated pentatope
Truncated 4-simplex
Truncated pentachoron (Acronym: tip) (Jonathan Bowers)
Coordinates
The Cartesian coordinates for the vertices of an origin-centered truncated 5-cell having edge length 2 are:
More simply, the vertices of the truncated 5-cell can be constructed on a hyperplane in 5-space as permutations of (0,0,0,1,2) or of (0,1,2,2,2). These coordinates come from positive orthant facets of the truncated pentacross and bitruncated penteract respectively.
Related polytopes
The convex hull of the truncated 5-cell and its dual (assuming that they are congruent) is a nonuniform polychoron composed of 60 cells: 10 tetrahedra, 20 octahedra (as triangular antiprisms), 30 tetrahedra (as tetragonal disphenoids), and 40 vertices. Its vertex figure is a hexakis triangular cupola.
Vertex figure
Bitruncated 5-cell
The bitruncated 5-cell (also called a bitruncated pentachoron, decachoron and 10-cell) is a 4-dimensional polytope, or 4-polytope, composed of 10 cells in the shape of truncated tetrahedra.
Topologically, under its highest symmetry, [[3,3,3]], there is only one geometrical form, containing 10 uniform truncated tetrahedra. The hexagons are always regular because of the polychoron's inversion symmetry, of which the regular hexagon is the only such case among ditrigons (an isogonal hexagon with 3-fold symmetry).
E. L. Elte identified it in 1912 as a semiregular polytope.
Each hexagonal face of the truncated tetrahedra is joined in complementary orientation to the neighboring truncated tetrahedron. Each edge is shared by two hexagons and one triangle. Each vertex is surrounded by 4 truncated tetrahedral cells in a tetragonal disphenoid vertex figure.
The bitruncated 5-cell is the intersection of two pentachora in dual configuration. As such, it is also the intersection of a penteract with the hyperplane that bisects the penteract's long diagonal orthogonally. In this sense it is a 4-dimensional analog of the regular octahedron (intersection of regular tetrahedra in dual configuration / tesseract bisection on long diagonal) and the regular hexagon (equilateral triangles / cube). The 5-dimensional analog is the birectified 5-simplex, and the -dimensional analog is the polytope whose Coxeter–Dynkin diagram is linear with rings on the middle one or two nodes.
The bitruncated 5-cell is one of the two non-regular convex uniform 4-polytopes which are cell-transitive. The other is the bitruncated 24-cell, which is composed of 48 truncated cubes.
Symmetry
This 4-polytope has a higher extended pentachoric symmetry (2×A4, [[3,3,3]]), doubled to order 240, because the element corresponding to any element of the underlying 5-cell can be exchanged with one of those corresponding to an element of its dual.
Alternative names
Bitruncated 5-cell (Norman W. Johnson)
10-cell as a cell-transitive 4-polytope
Bitruncated pentachoron
Bitruncated pentatope
Bitruncated 4-simplex
Decachoron (Acronym: deca) (Jonathan Bowers)
Images
Coordinates
The Cartesian coordinates of an origin-centered bitruncated 5-cell having edge length 2 are:
More simply, the vertices of the bitruncated 5-cell can be constructed on a hyperplane in 5-space as permutations of (0,0,1,2,2). These represent positive orthant facets of the bitruncated pentacross. Another 5-space construction, centered on the origin are all 20 permutations of (-1,-1,0,1,1).
Related polytopes
The bitruncated 5-cell can be seen as the intersection of two regular 5-cells in dual positions. = ∩ .
Configuration
Seen in a configuration matrix, all incidence counts between elements are shown. The diagonal f-vector numbers are derived through the Wythoff construction, dividing the full group order of a subgroup order by removing one mirror at a time.
Related regular skew polyhedron
The regular skew polyhedron, {6,4|3}, exists in 4-space with 4 hexagonal around each vertex, in a zig-zagging nonplanar vertex figure. These hexagonal faces can be seen on the bitruncated 5-cell, using all 60 edges and 30 vertices. The 20 triangular faces of the bitruncated 5-cell can be seen as removed. The dual regular skew polyhedron, {4,6|3}, is similarly related to the square faces of the runcinated 5-cell.
Disphenoidal 30-cell
The disphenoidal 30-cell is the dual of the bitruncated 5-cell. It is a 4-dimensional polytope (or polychoron) derived from the 5-cell. It is the convex hull of two 5-cells in opposite orientations.
Being the dual of a uniform polychoron, it is cell-transitive, consisting of 30 congruent tetragonal disphenoids. In addition, it is vertex-transitive under the group Aut(A4).
Related polytopes
These polytope are from a set of 9 uniform 4-polytope constructed from the [3,3,3] Coxeter group.
References
H.S.M. Coxeter:
H.S.M. Coxeter, Regular Polytopes, 3rd Edition, Dover New York, 1973
Kaleidoscopes: Selected Writings of H.S.M. Coxeter, edited by F. Arthur Sherk, Peter McMullen, Anthony C. Thompson, Asia Ivic Weiss, Wiley-Interscience Publication, 1995,
(Paper 22) H.S.M. Coxeter, Regular and Semi Regular Polytopes I, [Math. Zeit. 46 (1940) 380-407, MR 2,10]
(Paper 23) H.S.M. Coxeter, Regular and Semi-Regular Polytopes II, [Math. Zeit. 188 (1985) 559-591]
(Paper 24) H.S.M. Coxeter, Regular and Semi-Regular Polytopes III, [Math. Zeit. 200 (1988) 3-45]
Coxeter, The Beauty of Geometry: Twelve Essays, Dover Publications, 1999, p. 88 (Chapter 5: Regular Skew Polyhedra in three and four dimensions and their topological analogues, Proceedings of the London Mathematics Society, Ser. 2, Vol 43, 1937.)
Coxeter, H. S. M. Regular Skew Polyhedra in Three and Four Dimensions. Proc. London Math. Soc. 43, 33-62, 1937.
Norman Johnson Uniform Polytopes, Manuscript (1991)
N.W. Johnson: The Theory of Uniform Polytopes and Honeycombs, Ph.D. (1966)
x3x3o3o - tip, o3x3x3o - deca
Specific
Uniform 4-polytopes | Truncated 5-cell | Physics | 2,062 |
23,750,190 | https://en.wikipedia.org/wiki/C21H26N2O3 | {{DISPLAYTITLE:C21H26N2O3}}
The molecular formula C21H26N2O3 may refer to:
Corynanthine
Dregamine
Rauwolscine
Rhazine
Stemmadenine
Tabernaemontanine
Vincamine
Yohimbine | C21H26N2O3 | Chemistry | 61 |
4,704,252 | https://en.wikipedia.org/wiki/Raster%20scan | A raster scan, or raster scanning, is the rectangular pattern of image capture and reconstruction in television. By analogy, the term is used for raster graphics, the pattern of image storage and transmission used in most computer bitmap image systems. The word raster comes from the Latin word rastrum (a rake), which is derived from radere (to scrape); see also rastrum, an instrument for drawing musical staff lines. The pattern left by the lines of a rake, when drawn straight, resembles the parallel lines of a raster: this line-by-line scanning is what creates a raster. It is a systematic process of covering the area progressively, one line at a time. Although often a great deal faster, it is similar in the most general sense to how one's gaze travels when one reads lines of text.
In most modern graphics cards the data to be drawn is stored internally in an area of semiconductor memory called the framebuffer. This memory area holds the values for each pixel on the screen. These values are retrieved from the refresh buffer and painted onto the screen one row at a time.
Description
Scan lines
In a raster scan, an image is subdivided into a sequence of (usually horizontal) strips known as "scan lines". Each scan line can be transmitted in the form of an analog signal as it is read from the video source, as in television systems, or can be further divided into discrete pixels for processing in a computer system. This ordering of pixels by rows is known as raster order, or raster scan order. Analog television has discrete scan lines (discrete vertical resolution), but does not have discrete pixels (horizontal resolution) – it instead varies the signal continuously over the scan line. Thus, while the number of scan lines (vertical resolution) is unambiguously defined, the horizontal resolution is more approximate, according to how quickly the signal can change over the course of the scan line.
Scanning pattern
In raster scanning, the beam sweeps horizontally left-to-right at a steady rate, then blanks and rapidly moves back to the left, where it turns back on and sweeps out the next line. During this time, the vertical position is also steadily increasing (downward), but much more slowly – there is one vertical sweep per image frame, but one horizontal sweep per line of resolution. Thus each scan line is sloped slightly "downhill" (towards the lower right), with a slope of approximately –1/horizontal resolution, while the sweep back to the left (retrace) is significantly faster than the forward scan, and essentially horizontal. The resulting tilt in the scan lines is very small, and is dwarfed in effect by screen convexity and other modest geometrical imperfections.
There is a misconception that once a scan line is complete, a cathode-ray tube (CRT) display in effect suddenly jumps internally, by analogy with a typewriter or printer's paper advance or line feed, before creating the next scan line. As discussed above, this does not exactly happen: the vertical sweep continues at a steady rate over a scan line, creating a small tilt. Steady-rate sweep is done, instead of a stairstep of advancing every row, because steps are hard to implement technically, while steady-rate is much easier. The resulting tilt is compensated in most CRTs by the tilt and parallelogram adjustments, which impose a small vertical deflection as the beam sweeps across the screen. When properly adjusted, this deflection exactly cancels the downward slope of the scanlines. The horizontal retrace, in turn, slants smoothly downward as the tilt deflection is removed; there's no jump at either end of the retrace. In detail, scanning of CRTs is performed by magnetic deflection, by changing the current in the coils of the deflection yoke. Rapidly changing the deflection (a jump) requires a voltage spike to be applied to the yoke, and the deflection can only react as fast as the inductance and spike magnitude permit. Electronically, the inductance of the deflection yoke's vertical windings is relatively high, and thus the current in the yoke, and therefore the vertical part of the magnetic deflection field, can change only slowly.
In fact, spikes do occur, both horizontally and vertically, and the corresponding horizontal blanking interval and vertical blanking interval give the deflection currents settle time to retrace and settle to their new value. This happens during the blanking interval.
In electronics, these (usually steady-rate) movements of the beam[s] are called "sweeps", and the circuits that create the currents for the deflection yoke (or voltages for the horizontal deflection plates in an oscilloscope) are called the sweep circuits. These create a sawtooth wave: steady movement across the screen, then a typically rapid move back to the other side, and likewise for the vertical sweep.
Furthermore, wide-deflection-angle CRTs need horizontal sweeps with current that changes proportionally faster toward the center, because the center of the screen is closer to the deflection yoke than the edges. A linear change in current would swing the beams at a constant rate angularly; this would cause horizontal compression toward the center.
Printers
Computer printers create their images basically by raster scanning. Laser printers use a spinning polygonal mirror (or an optical equivalent) to scan across the photosensitive drum, and paper movement provides the other scan axis. Considering typical printer resolution, the "downhill" effect is minuscule. Inkjet printers have multiple nozzles in their printheads, so many (dozens to hundreds) of "scan lines" are written together, and paper advance prepares for the next batch of scan lines. Transforming vector-based data into the form required by a display, or printer, requires a Raster Image Processor (RIP).
Fonts
Computer text is mostly created from font files that describe the outlines of each printable character or symbol (glyph). (A minority are "bit maps".) These outlines have to be converted into what are effectively little rasters, one per character, before being rendered (displayed or printed) as text, in effect merging their little rasters into that for the page.
Video timing
In detail, each line (horizontal frame or HFrame) consists of:
scanline, when beam is unblanked, and moving steadily to the right
front porch, when beam is blanked, and moving steadily to the right
sync pulse, when beam is blanked, and moves rapidly back to the left
back porch, when beam is blanked, and again moving steadily to the right.
The porches and associated blanking are to provide fall time and settle time for the beam to move back to the left (the voltage to decrease), and for ringing to die down. The vertical frame (VFrame) consists of exactly the same components, but only occurs once per image frame, and the times are considerably longer. The details of these intervals are called the video timing. See Video timing details revealed for a diagram of these. These are mostly not visible to end users, but were visible in the case of XFree86 Modelines, where users of XFree86 could (and sometimes needed to) manually adjust these timings, particularly to achieve certain resolutions or refresh rates.
Perception
Raster scan on CRTs produces both the impression of a steady image from a single scanning point (only one point is being drawn at a time) through several technical and psychological processes. These images then produce the impression of motion in largely the same way as film – a high enough frame rate of still images yields the impression of motion – though raster scans differ in a few respects, particularly interlacing.
Firstly, due to phosphor persistence, even though only one "pixel" is being drawn at a time (recall that on an analog display, "pixel" is ill-defined, as there are no fixed horizontal divisions; rather, there is a "flying spot"), by the time the whole screen has been painted, the initial pixel is still relatively illuminated. Its brightness will have dropped some, which can cause a perception of flicker. This is one reason for the use of interlacing – since only every other line is drawn in a single field of broadcast video, the bright newly drawn lines interlaced with the somewhat dimmed older drawn lines create relatively more even illumination.
Second, by persistence of vision, the viewed image persists for a moment on the retina, and is perceived as relatively steady. By the related flicker fusion threshold, these pulsating pixels appear steady.
These perceptually steady still images are then pieced together to produce a moving picture, similar to a movie projector. However, one must bear in mind that in film projectors, the full image is projected at once (not in a raster scan), uninterlaced, based on a frame rate of 24 frames per second. By contrast, a raster scanned interlaced video produces an image 50 or 60 fields per second (a field being every other line, thus corresponding to a frame rate of 25 or 30 frames per second), with each field being drawn a pixel at a time, rather than the entire image at once. These both produce a video, but yield somewhat different perceptions or "feel".
Theory and history
In a CRT display, when the electron beams are unblanked, the horizontal deflection component of the magnetic field created by the deflection yoke makes the beams scan "forward" from left to right at a constant rate. The data for consecutive pixels goes (at the pixel clock rate) to the digital-to-analog converters for each of the three primary colors (for modern flat-panel displays, however, the pixel data remains digital). As the scan line is drawn, at the right edge of the display, all beams are blanked, but the magnetic field continues to increase in magnitude for a short while after blanking.
To clear up possible confusion: Referring to the magnetic deflection fields, if there were none, all beams would hit the screen near the center. The farther away from the center, the greater the strength of the field needed. Fields of one polarity move the beam up and left, and those of the opposite polarity move it down and right. At some point near the center, the magnetic deflection field is zero. Therefore, a scan begins as the field decreases. Midway, it passes through zero, and smoothly increases again to complete the scan.
After one line has been created on the screen and the beams are blanked, the magnetic field reaches its designed maximum. Relative to the time required for a forward scan, it then changes back relatively quickly to what's required to position the beam beyond the left edge of the visible (unblanked) area. This process occurs with all beams blanked, and is called the retrace. At the left edge, the field steadily decreases in magnitude to start another forward scan, and soon after the start, the beams unblank to start a new visible scan line.
A similar process occurs for the vertical scan, but at the display refresh rate (typically 50 to 75 Hz). A complete field starts with a polarity that would place the beams beyond the top of the visible area, with the vertical component of the deflection field at maximum. After some tens of horizontal scans (but with the beams blanked), the vertical component of the unblank, combined with the horizontal unblank, permits the beams to show the first scan line. Once the last scan line is written, the vertical component of the magnetic field continues to increase by the equivalent of a few percent of the total height before the vertical retrace takes place. Vertical retrace is comparatively slow, occurring over a span of time required for several tens of horizontal scans. In analog CRT TVs, setting brightness to maximum typically made the vertical retrace visible as zigzag lines on the picture.
In analog TV, originally it was too costly to create a simple sequential raster scan of the type just described with a fast-enough refresh rate and sufficient horizontal resolution, although the French 819-line system had better definition than other standards of its time. To obtain a flicker-free display, analog TV used a variant of the scheme in moving-picture film projectors, in which each frame of the film is shown twice or three times. To do that, the shutter closes and opens again to increase the flicker rate, but not the data update rate.
Interlaced scanning
To reduce flicker, analog CRT TVs write only odd-numbered scan lines on the first vertical scan; then, the even-numbered lines follow, placed ("interlaced") between the odd-numbered lines. This is called interlaced scanning. (In this case, positioning the even-numbered lines does require precise position control; in old analog TVs, trimming the Vertical Hold adjustment made scan lines space properly. If slightly misadjusted, the scan lines would appear in pairs, with spaces between.) Modern high-definition TV displays use data formats like progressive scan in computer monitors (such as "1080p", 1080 lines, progressive), or interlaced (such as "1080i").
Radar
Raster scans have been used in (naval gun) fire-control radar, although they were typically narrow rectangles. They were used in pairs (for bearing, and for elevation). In each display, one axis was angular offset from the line of sight, and the other, range. Radar returns brightened the video. Search and weather radars have a circular display (Plan Position Indicator, PPI) that covers a round screen, but this is not technically a raster. Analog PPIs have sweeps that move outward from the center, and the angle of the sweep matches antenna rotation, up being north, or the bow of the ship.
Television
The use of raster scanning in television was proposed in 1880 by French engineer Maurice Leblanc. The concept of raster scanning was inherent in the original mechanical disc-scanning television patent of Paul Nipkow in 1884. The term raster was used for a halftone printing screen pattern as early as 1894. Similar terminology was used in German at least from 1897; Eder writes of "die Herstellung von Rasternegativen für Zwecke der Autotypie" (the production of raster negatives for halftones). Max Dieckmann and Gustav Glage were the first to produce actual raster images on a cathode-ray tube (CRT); they patented their techniques in Germany in 1906. It has not been determined whether they used the word raster in their patent or other writings.
An early use of the term raster with respect to image scanning via a rotating drum is Arthur Korn's 1907 book which says (in German): "...als Rasterbild auf Metall in solcher Weise aufgetragen, dass die hellen Töne metallisch rein sind, oder umgekehrt" (...as a raster image laid out on metal in such way that the bright tones are metallically pure, and vice versa). Korn was applying the terminology and techniques of halftone printing, where a "Rasterbild" was a halftone-screened printing plate. There were more scanning-relevant uses of Raster by German authors Eichhorn in 1926: "die Tönung der Bildelemente bei diesen Rasterbildern" and "Die Bildpunkte des Rasterbildes" ("the tone of the picture elements of this raster image" and "the picture points of the raster image"); and Schröter in 1932: "Rasterelementen," "Rasterzahl," and "Zellenraster" ("raster elements," "raster count," and "cell raster").
The first use of raster specifically for a television scanning pattern is often credited to Baron Manfred von Ardenne who wrote in 1933: "In einem Vortrag im Januar 1930 konnte durch Vorführungen nachgewiesen werden, daß die Braunsche Röhre hinsichtlich Punktschärfe und Punkthelligkeit zur Herstellung eines präzisen, lichtstarken Rasters laboratoriumsmäßig durchgebildet war" (In a lecture in January 1930 it was proven by demonstrations that the Braun tube was prototyped in the laboratory with point sharpness and point brightness for the production of a precise, bright raster). Raster was adopted into English television literature at least by 1936, in the title of an article in Electrician. The mathematical theory of image scanning was developed in detail using Fourier transform techniques in a classic paper by Mertz and Gray of Bell Labs in 1934.
CRT components
Electronic gun:-
Primary gun: used to store the picture pattern.
Flood gun: used to maintain the picture display.
Phosphor coated screen: coated with phosphors that emit light when an electron beam strikes them.
Focusing system: focusing system causes the electron beam to converge into a small spot as it strikes the phosphor screen.
Deflection system: used to change the direction of electron beam so it can be made to strike at different locations on the phosphor screen.
See also
Broadcast television systems
Cathode-ray tube
Computer display standard
Counter-scanning
Image resolution
Raster graphics
Rasterisation
References
Television technology
Computer graphics
fr:Trame | Raster scan | Technology | 3,683 |
1,833,833 | https://en.wikipedia.org/wiki/Motilin | Motilin is a 22-amino acid polypeptide hormone in the motilin family that, in humans, is encoded by the MLN gene.
Motilin is secreted by endocrine Mo cells (also referred to as M cells, which are not the same as the M cells, or microfold cells, found in Peyer's patches) that are numerous in crypts of the small intestine, especially in the duodenum and jejunum. It is released into the general circulation in humans at about 100-min intervals during the inter-digestive state and is the most important factor in controlling the inter-digestive migrating contractions; and it also stimulates endogenous release of the endocrine pancreas. Based on amino acid sequence, motilin is unrelated to other hormones. Because of its ability to stimulate gastric activity, it was named "motilin." Apart from in humans, the motilin receptor has been identified in the gastrointestinal tracts of pigs, rats, cows, and cats, and in the central nervous system of rabbits.
Discovery
Motilin was discovered by J.C. Brown when he introduced alkaline solution into duodena of dogs, which caused strong gastric contractions. Brown et al. predicted that alkali could either release stimulus to activate motor activity or prevent the secretion of inhibitory hormone. They isolated a polypeptide as a by-product from purification of secretin on carboxymethyl cellulose. They named this polypeptide "Motilin."
Structure
Motilin has 22 amino acids and molecular weight of 2698 daltons. In extract from human gut and plasma, there are two basic forms of motilin. The first molecular form is the polypeptide of 22 amino acids. The second form, on the other hand, is larger and contains the same 22 amino acids as the first form but includes an additional carboxyl-terminus end.
The sequences of amino acids of motilin is: Phe-Val-Pro-Ile-Phe-Thr-Tyr-Gly-Glu-Leu-Gln-Arg-Met-Gln-Glu-Lys-Glu-Arg-Asn-Lys-Gly-Gln.
The structure and dynamics of the gastrointestinal peptide hormone motilin have been studied in the presence of isotropic q = 0.5 phospholipid bicelles. The NMR solution structure of the peptide in acidic bicelle solution was determined from 203 NOE-derived distance constraints and six backbone torsion angle constraints. Dynamic properties for the 13Cα→1H vector in Leu-10 were determined for motilin specifically labeled with 13C at this position by analysis of multiple-field relaxation data. The structure reveals an ordered alpha-helical conformation between Glu-9 and Lys-20. The N-terminus is also well structured with a turn resembling that of a classical beta-turn. The 13C dynamics clearly show that motilin tumbles slowly in solution, with a correlation time characteristic of a large object.
Stimulus
How the secretion of motilin is regulated is largely unknown, although some studies suggest that an alkaline pH in the duodenum stimulates its release. However, at low pH it inhibits gastric motor activity, whereas at high pH it has a stimulatory effect. Some studies in dogs have shown that motilin is released during fasting or interdigestive period, and intake of food during this period can prevent the secretion of motilin. Intravenous injection of glucose, which increases the release of insulin, is also found to inhibit cyclic elevation of plasma motilin. Other studies on dogs have also suggested that motilin acted as endogenous ligand in positive feedback mechanism to stimulate the release of more motilin. In dogs and cats, motilin secretion is stimulated by hydrogen ions (protons) and lipids when the animal is in a "fed" state. However, during fasting, motilin is periodically released into the serum to initiate phase III of the migrating motor complex.
Function
The main function of motilin is to increase the migrating myoelectric complex component of gastrointestinal motility and stimulate the production of pepsin. Motilin is also called "housekeeper of the gut" because it improves peristalsis in the small intestine and clears out the gut to prepare for the next meal. A high level of motilin secreted between meals into the blood stimulates the contraction of the fundus and antrum and accelerates gastric emptying. It then contracts the gallbladder and increases the squeeze pressure of the lower esophageal sphincter. Other functions of motilin include increasing the release of pancreatic polypeptide and somatostatin.
Motilin agonists
Erythromycin, Mitemcinal and related antibiotics act as non-peptide motilin agonists, and are sometimes used for their ability to stimulate gastrointestinal motility. In the case of erythromycin, it is its hemiketal intermediate, formed after an oral dose in the low-pH environment of the stomach lumen, which directly acts on the motilin receptor. Administration of a low dose of erythromycin will induce peristalsis, which provides additional support for the conclusion that motilin secretion triggers this pattern of gastrointestinal motility, rather than results from it. However, some of erythromycin's properties, including antibiotic activity, are not appropriate for a drug designed for chronic use over a patient's lifetime.
New motilin agonists are erythromycin-based; however, it may be that this class of drugs becomes redundant. Growth hormone secretagogue receptors share 52% of their DNA with motilin receptors, and agonists of these receptors, termed ghrelins, can bring about similar effects to motilin agonists.
Camicinal is a motilin agonist under development.
Xylitol ingestion also increases motilin secretion, which may be related to xylitol's ability to cause diarrhea.
Related peptides
This domain is also found in ghrelin, a growth hormone secretagogue synthesised by endocrine cells in the stomach. Ghrelin stimulates growth hormone secretagogue receptors in the pituitary. These receptors are distinct from the growth hormone-releasing hormone receptors, and, thus, provide a means of controlling pituitary growth hormone release by the gastrointestinal system.
Erythromycin has an advantage over metoclopramide in gastric emptying due to lack of central nervous system side-effects. It is not approved by FDA to use for gastric emptying. For short duration for patients with diabetes and for those that must clear the stomach for any procedure, it may be used based on the physician's discretion with full understanding that it is not approved by FDA for this use.
Human proteins
GHRL; Motilin;
References
External links
Intestinal hormones
Motilin receptor agonists
Protein domains
Hormones | Motilin | Biology | 1,527 |
47,681,779 | https://en.wikipedia.org/wiki/ODINUS | ODINUS (Origins, Dynamics, and Interiors of the Neptunian and Uranian Systems) is a space mission concept proposed to the European Space Agency's Cosmic Vision programme. The ODINUS mission concept proposes to expand the Uranus orbiter and probe mission to two twin orbiters— dubbed Freyr and Freyja, the twin gods of the Norse pantheon. Their primary mission would be to study Neptune and Uranus with one orbiter each. If selected, ODINUS would launch in 2034.
Instruments
The following six instruments are considered essential to the mission:
Camera (Wide and Narrow Angle) – Designed to image the planet at the same level of detail as missions to the two gas giants have provided.
VIS-NIR Image Spectrometer
Magnetometer – To study the magnetic fields of Neptune.
Mass Spectrometer (Ions and Neutrals, INMS)
Doppler Spectro-Imager – To take seismic measurements.
Microwave Radiometer
The following two additional instruments are strongly desired by the mission proposers:
Energetic Neutral Atoms Detector – To complement the measurements of the INMS.
High-sensitivity Accelerometer – To be used in the atmospheric descent phase.
See also
Exploration of Neptune
Exploration of Uranus
Uranus mission proposals
Uranus Orbiter and Probe
MUSE
OCEANUS
Uranus Pathfinder
References
Proposed space probes
Missions to Uranus
Missions to Neptune
Orbiters (space probe)
European Space Agency space probes | ODINUS | Astronomy | 288 |
15,342,640 | https://en.wikipedia.org/wiki/DPSIR | DPSIR (drivers, pressures, state, impact, and response model of intervention) is a causal framework used to describe the interactions between society and the environment. It seeks to analyze and assess environmental problems by bringing together various scientific disciplines, environmental managers, and stakeholders, and solve them by incorporating sustainable development. First, the indicators are categorized into "drivers" which put "pressures" in the "state" of the system, which in turn results in certain "impacts" that will lead to various "responses" to maintain or recover the system under consideration. It is followed by the organization of available data, and suggestion of procedures to collect missing data for future analysis. Since its formulation in the late 1990s, it has been widely adopted by international organizations for ecosystem-based study in various fields like biodiversity, soil erosion, and groundwater depletion and contamination. In recent times, the framework has been used in combination with other analytical methods and models, to compensate for its shortcomings. It is employed to evaluate environmental changes in ecosystems, identify the social and economic pressures on a system, predict potential challenges and improve management practices. The flexibility and general applicability of the framework make it a resilient tool that can be applied in social, economic, and institutional domains as well.
History
The Driver-Pressure-State-Impact-Response framework was developed by the European Environment Agency (EEA) in 1999. It was built upon several existing environmental reporting frameworks, like the Pressure-State-Response (PSR) framework developed by the Organization for Economic Co-operation and Development (OECD) in 1993, which itself was an extension of Rapport and Friend's Stress-Response (SR) framework (1979). The PSR framework simplified environmental problems and solutions into variables that stress the cause-effect relationship between human activities that exert pressure on the environment, the state of the environment, and society's response to the condition. Since it focused on anthropocentric pressures and responses, it did not effectively factor natural variability into the pressure category. This led to the development of the expanded Driving Force-State-Response (DSR) framework, by the United Nations Commission on Sustainable Development (CSD) in 1997. A primary modification was the expansion of the concept of “pressure” to include social, political, economic, demographic, and natural system pressures. However, by replacing “pressure” with “driving force”, the model failed to account for the underlying reasons for the pressure, much like its antecedent. It also did not address the motivations behind responses to changes in the state of the environment. The refined DPSIR model sought to address these shortcomings of its predecessors by addressing root causes of the human activities that impact the environment, by incorporating natural variability as a pressure on the current state and addressing responses to the impact of changes in state on human well-being. Unlike PSR and DSR, DPSIR is not a model, but a means of classifying and disseminating information related to environmental challenges. Since its conception, it has evolved into modified frameworks like Driver-Pressure-Chemical State-Ecological State-Response (DPCER), Driver-Pressure-State-Welfare-Response (DPSWR), and Driver-Pressure-State-Ecosystem-Response (DPSER).
The DPSIR Framework
Driver (Driving Force)
Driver refers to the social, demographic, and economic developments which influence the human activities that have a direct impact on the environment. They can further be subdivided into primary and secondary driving forces. Primary driving forces refer to technological and societal actors that motivate human activities like population growth and distribution of wealth. The developments induced by these drivers give rise to secondary driving forces, which are human activities triggering “pressures” and “impacts”, like land-use changes, urban expansion and industrial developments. Drivers can also be identified as underlying or immediate, physical or socio-economic, and natural or anthropogenic, based on the scope and sector in which they are being used.
Pressure
Pressure represents the consequence of the driving force, which in turn affects the state of the environment. They are usually depicted as unwanted and negative, based on the concept that any change in the environment caused by human activities is damaging and degrading. Pressures can have effects on the short run (e.g.: deforestation), or the long run (e.g.: climate change), which if known with sufficient certainty, can be expressed as a probability. They can be both human-induced, like emissions, fuel extraction, and solid waste generation, and natural processes, like solar radiation and volcanic eruptions. Pressures can also be sub-categorized as endogenic managed pressures, when they stem from within the system and can be controlled (e.g.: land claim, power generation), and as exogenic unmanaged pressures, when they stem from outside the system and cannot be controlled (e.g.: climate change, geomorphic activities).
State
State describes the physical, chemical and biological condition of the environment or observable temporal changes in the system. It may refer to natural systems (e.g.: atmospheric CO2 concentrations, temperature), socio-economic systems (e.g.: living conditions of humans, economic situations of an industry), or a combination of both (e.g.: number of tourists, size of current population). It includes a wide range of features, like physico-chemical characteristics of ecosystems, quantity and quality of resources or “carrying capacity”, management of fragile species and ecosystems, living conditions for humans, and exposure or the effects of pressures on humans. It is not intended to just be static, but to reflect current trends as well, like increasing eutrophication and change in biodiversity.
Impact
Impact refers to how changes in the state of the system affect human well-being. It is often measured in terms of damages to the environment or human health, like migration, poverty, and increased vulnerability to diseases, but can also be identified and quantified without any positive or negative connotation, by simply indicating a change in the environmental parameters. Impact can be ecologic (e.g.: reduction of wetlands, biodiversity loss), socio-economic (e.g.: reduced tourism), or a combination of both. Its definition may vary depending on the discipline and methodology applied. For instance, it refers to the effect on living beings and non-living domains of ecosystems in biosciences (e.g.: modifications in the chemical composition of air or water), whereas it is associated with the effects on human systems related to changes in the environmental functions in socio-economic sciences (e.g.: physical and mental health).
Response
Response refers to actions taken to correct the problems of the previous stages, by adjusting the drivers, reducing the pressure on the system, bringing the system back to its initial state, and mitigating the impacts. It can be associated uniquely with policy action, or to different levels of the society, including groups and/or individuals from the private, government or non-governmental sectors. Responses are mostly designed and/or implemented as political actions of protection, mitigation, conservation, or promotion. A mix of effective top-down political action and bottom-up social awareness can also be developed as responses, such as eco-communities or improved waste recycling rates.
Criticisms and Limitations
Despite the adaptability of the framework, it has faced several criticisms. One of the main goals of the framework is to provide environmental managers, scientists of various disciplines, and stakeholders with a common forum and language to identify, analyze and assess environmental problems and consequences. However, several notable authors have mentioned that it lacks a well-defined set of categories, which undermines the comparability between studies, even if they are similar. For instance, climate change can be considered as a natural driver, but is primarily caused by greenhouse gases (GSG) produced by human activities, which may be categorized under “pressure”. A wastewater treatment plant is considered a response while dealing with water pollution, but a pressure when effluent runoff leading to eutrophication is taken into account. This ambivalence of variables associated with the framework has been criticized as a lack of good communication between researchers and between stakeholders and policymakers. Another criticism is the misguiding simplicity of the framework, which ignores the complex synergy between the categories. For instance, an impact can be caused by various different state conditions and responses to other impacts, which is not addressed by DPSIR. Some authors also argue that the framework is flawed as it does not clearly illustrate the cause-effect linkage for environmental problems. The reasons behind these contextual differences seem to be differences in opinions, characteristics of specific case studies, misunderstanding of the concepts and inadequate knowledge of the system under consideration.
DPSIR was initially proposed as a conceptual framework rather than a practical guidance, by global organizations. This means that at a local level, analyses using the framework can cause some significant problems. DPSIR does not encourage the examination of locally specific attributes for individual decisions, which when aggregated, could have potentially large impacts on sustainability. For instance, a farmer who chooses a particular way of livelihood may not create any consequential alterations on the system, but the aggregation of farmers making similar choices will have a measurable and tangible effect. Any efforts to evaluate sustainability without considering local knowledge could lead to misrepresentations of local situations, misunderstandings of what works in particular areas and even project failure.
While there is no explicit hierarchy of authority in the DPSIR framework, the power difference between “developers” and the “developing” could be perceived as the contributor to the lack of focus on local, informal responses at the scale of drivers and pressures, thus compromising the validity of any analysis conducted using it. The “developers” refer to the Non-Governmental Organizations (NGOs), State mechanisms and other international organizations with the privilege to access various resources and power to use knowledge to change the world, and the “developing” refers to local communities. According to this criticism, the latter is less capable of responding to environmental problems than the former. This undermines valuable indigenous knowledge about various components of the framework in a particular region, since the inclusion of the knowledge is almost exclusively left at the discretion of the “developers”.
Another limitation of the framework is the exclusion of social and economic developments on the environment, particularly for future scenarios. Furthermore, DPSIR does not explicitly prioritize responses and fails to determine the effectiveness of each response individually, when working with complex systems. This has been one of the most criticized drawbacks of the framework, since it fails to capture the dynamic nature of real-world problems, which cannot be expressed by simple causal relations.
Applications
Despite its criticisms, DPSIR continues to be widely used to frame and assess environmental problems to identify appropriate responses. Its main objective is to support sustainable management of natural resources. DPSIR structures indicators related to the environmental problem addressed with reference to the political objectives and focuses on supposed causal relationships effectively, such that it appeals to policy actors. Some examples include the assessment of the pressure of alien species, evaluation of impacts of developmental activities on the coastal environment and society, identification of economic elements affecting global wildfire activities, and cost-benefit analysis (CBA) and gross domestic product (GDP) correction.
To compensate for its shortcomings, DPSIR is also used in conjunction with several analytical methods and models. It has been used in conjunction with Multiple-Criteria Decision Making (MCDM) for desertification risk management, with Analytic Hierarchy Process (AHP) to study urban green electricity power, and with Tobit model to assess freshwater ecosystems. The framework itself has also been modified to assess specific systems, like DPSWR, which focuses on the impacts on human welfare alone, by shifting ecological impact to the state category. Another approach is a differential DPSIR (ΔDPSIR), which evaluates the changes in drivers, pressures and state after implementing a management response, making it valuable both as a scientific output and a system management tool. The flexibility offered by the framework makes it an effective tool with numerous applications, provided the system is properly studied and understood by the stakeholders.
References
External links
DPSIR-Model of the European Environment Agency (EEA)
Environmental terminology
Industrial ecology | DPSIR | Chemistry,Engineering | 2,535 |
359,377 | https://en.wikipedia.org/wiki/Abstract%20structure | An abstract structure is an abstraction that might be of the geometric spaces
or a set structure, or a hypostatic abstraction that is defined by a set of mathematical theorems and laws, properties and relationships in a way that is logically if not always historically independent of the structure of contingent experiences, for example, those involving physical objects. Abstract structures are studied not only in logic and mathematics but in the fields that apply them, as computer science and computer graphics, and in the studies that reflect on them, such as philosophy (especially the philosophy of mathematics). Indeed, modern mathematics has been defined in a very general sense as the study of abstract structures (by the Bourbaki group: see discussion there, at algebraic structure and also structure).
An abstract structure may be represented (perhaps with some degree of approximation) by one or more physical objectsthis is called an implementation or instantiation of the abstract structure. But the abstract structure itself is defined in a way that is not dependent on the properties of any particular implementation.
An abstract structure has a richer structure than a concept or an idea. An abstract structure must include precise rules of behaviour which can be used to determine whether a candidate implementation actually matches the abstract structure in question, and it must be free from contradictions. Thus we may debate how well a particular government fits the concept of democracy, but there is no room for debate over whether a given sequence of moves is or is not a valid game of chess (for example Kasparovian approaches).
Examples
A sorting algorithm is an abstract structure, but a recipe is not, because it depends on the properties and quantities of its ingredients.
A simple melody is an abstract structure, but an orchestration is not, because it depends on the properties of particular instruments.
Euclidean geometry is an abstract structure, but the theory of continental drift is not, because it depends on the geology of the Earth.
A formal language is an abstract structure, but a natural language is not, because its rules of grammar and syntax are open to debate and interpretation.
Notes
See also
Abstraction in computer science
Abstraction in general
Abstraction in mathematics
Abstract object
Deductive apparatus
Formal sciences
Mathematical structure
Abstraction
Mathematical terminology
Structure
da:Abstrakt (begreb) | Abstract structure | Mathematics | 451 |
2,382,971 | https://en.wikipedia.org/wiki/Pyramidion | A pyramidion (plural: pyramidia) is the capstone of an Egyptian pyramid or the upper section of an obelisk. Speakers of the Ancient Egyptian language referred to pyramidia as benbenet and associated the pyramid as a whole with the sacred benben stone.
Pyramidia were usually made of limestone, sandstone, basalt or granite, and were sometimes covered with plates of copper, gold or electrum. From the Middle Kingdom onward, they were often "inscribed with royal titles and religious symbols".
Notable pyramidia
Egyptian Museum
Four pyramidia are housed in the main hall of the Egyptian Museum in Cairo:
The pyramidion of the so-called Black Pyramid of Amenemhat III at Dahshur
The pyramidion of the Pyramid of Khendjer at Saqqara
The pyramidion of Merneferre Ay, probably from Saqqara
The pyramidion of the Southern South Saqqara pyramid
Red Pyramid
A badly damaged white Tura limestone pyramidion, thought to have been made for the Red Pyramid of Sneferu at Dahshur, has been reconstructed and is on open-air display beside that pyramid; it presents a minor mystery, however, as its angle of inclination is steeper than that of the edifice it was apparently built to surmount.
Private brick pyramids with pyramidia
During the New Kingdom, some private underground tombs were marked on the surface by small brick pyramids that terminated in pyramidia. The four lateral sides included texts and scenes related to the cult of the Sun God (as the representation of Pharaoh).
The scenes typically depict the course of the sun, rising on one lateral face, setting on the opposite face, and traveling, through the night, through the underworld, ruled by Osiris.
Scribe Mose pyramidion
The pyramidion of Mose (mes,s, New Kingdom, 19th Dynasty, , limestone, 53 cm tall) depicts himself making an offering, with his name on two opposite faces. The adjacent opposite faces feature a baboon: "Screeching upon the rising of the Sun, and the Day". (The baboon is also the god-scribe representation of the Scribe, for the god Thoth.)
Ptahemwia pyramidion
The pyramidion of Ptahemwia (19th Dynasty, Ramesside Period, , limestone, 28 cm wide, 42 cm tall) likewise displays sun-related scenes. The Sun God, Re-Horakhti, and the god of the Underworld, Osiris, are shown on one lateral face.
Facing the two gods, on the adjacent lateral face, is the deceased Ptahemwia, standing in an offering pose, facing three columns of hieroglyphs.
Gallery
See also
Washington Monument, which has an aluminum pyramidion
References
External links
Ancient Egyptian pyramids
Architectural elements
Egyptian artefact types
Sacred rocks | Pyramidion | Technology,Engineering | 587 |
29,949,856 | https://en.wikipedia.org/wiki/Nesmeyanov%20Institute%20of%20Organoelement%20Compounds | The A.N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences (INEOS RAS) () is a research centre founded in 1954 by the president of the USSR Academy of Sciences, Alexander Nesmeyanov. After his exit, the insitute was ran by A.V. Fokin from 1980 to 1988, M.E. Vol’pin (1989-1996), Yu.N.Bubnov (1996-2013), A.M. Muzafarov (2013-2018), and A.A. Trifonov (2018)
In 2019 and 2020 scientific journal "Journal of Organometallic Chemistry" decided to publish two special issues on the occasion of the 120th anniversary of the famous Russian organometallic chemist Alexander N. Nesmeyanov and the occasion of the 70th birthday of professor Elena Shubina, to note the scientific contribution of scientists in organometallics and the field of non-covalent interactions (Shubina).
External links
Research institutes in the Soviet Union
Institutes of the Russian Academy of Sciences
Chemical research institutes
1954 establishments in the Soviet Union
Research institutes established in 1954 | Nesmeyanov Institute of Organoelement Compounds | Chemistry | 242 |
1,212,157 | https://en.wikipedia.org/wiki/Diomidis%20Spinellis | Diomidis D. Spinellis (; 2 February 1967, Athens) is a Greek computer science academic and author of the books Code Reading, Code Quality, Beautiful Architecture (co-author) and Effective Debugging.
Education
Spinellis holds a Master of Engineering degree in Software Engineering and a Ph.D. in Computer Science both from Imperial College London. His PhD was supervised by Susan Eisenbach and Sophia Drossopoulou.
Career and research
He is a professor at the Department of Management Science and Technology at the Athens University of Economics and Business, and a member of the IEEE Software editorial board, contributing the Tools of the Trade column. Since 2014, he is also editor-in-chief of IEEE Software. Spinellis is a four-time winner of the International Obfuscated C Code Contest in 1988, 1990, 1991 and 1995.
He is also a committer in the FreeBSD project, and author of a number of popular free or open-source systems: the UMLGraph declarative UML diagram generator, the bib2xhtml BibTeX to XHTML converter, the outwit Microsoft Windows data with command line programs integration tool suite, the CScout source code analyzer and refactoring browser, the socketpipe fast inter-process communication plumbing utility and directed graph shell the directed graph Unix shell for big data and stream processing pipelines.
In 2008, together with a collaborator, Spinellis claimed that "red links" (a Wikipedia slang for wikilinks that lead to non-existing pages) is what drives Wikipedia growth.
On 5 November 2009 he was appointed the General Secretary of Information Systems at the Greek Ministry of Finance. In October 2011, he resigned citing personal reasons.
On 20 March 2015 he was elected President of Open Technologies Alliance (GFOSS). GFOSS is a non-profit organization founded in 2008, 36 Universities and Research Centers are shareholders of GFOSS. The main goal of GFOSS is to promote Openness through the use and the development of Open Standards and Open Technologies in Education, Public Administration and Business in Greece. Spinellis uses open-source software to teach software engineering to his students.
References
1967 births
Alumni of the Department of Computing, Imperial College London
Greek computer programmers
Computer systems researchers
Greek computer scientists
Living people
Software engineers
Greek technology writers
Academic staff of the Athens University of Economics and Business
Scientists from Athens | Diomidis Spinellis | Engineering | 491 |
44,484,961 | https://en.wikipedia.org/wiki/Austroboletus%20neotropicalis | Austroboletus neotropicalis is a bolete fungus found in Costa Rica, where it grows under oak.
References
External links
neotropicalis
Fungi described in 1991
Fungi of Central America
Fungus species | Austroboletus neotropicalis | Biology | 41 |
37,699,920 | https://en.wikipedia.org/wiki/US%20state%20laws%20and%20policies%20for%20ICT%20accessibility | Many individual states within the US have accessibility policies for Information and Communications Technology (ICT). These policies often include references to national or international standards. They provide websites and software authors with technical details to ensure that users with disabilities can access the information and that adequate functionality is assured. The most commonly referenced standards are Section 508 and the W3C's Web Content Accessibility Guidelines. The table below provides information for all fifty states and indicates whether policies are in place for websites and software. It also indicates what standards the web policies are based on and provides links to the policies.
External links
Blindness equipment
Computer accessibility
Computer law | US state laws and policies for ICT accessibility | Technology | 125 |
8,509,760 | https://en.wikipedia.org/wiki/FireWave | The FireWave is a device that is, essentially, an external FireWire soundcard made by Griffin Technology as a third party accessory for Apple Inc.'s line of personal computers.
FireWave uses the FireWire (IEEE 1394) port of the Mac as an audio output to its Dolby Digital sound processing hardware, effectively acting as an external soundcard.
Griffin Technology's product website explains that FireWave uses the Dolby processors to allow the user to connect a 5.1 surround sound system. Speakers are then connected directly to FireWave's speaker terminals. Many different sound setups and configurations are possible, using a combination of Griffin's included FireWave software and Apple's "Audio MIDI Setup" utility.
Griffin Technology's website lists the Griffin FireWave as a discontinued item.
Technical
FireWave has six output channels through three 1/8” (3.5 mm) stereo mini-jacks: Left/Right, Center/Subwoofer and Right Surround/Left Surround. There is also a passthrough FireWire port to allow for chaining more FireWire devices.
FireWave supports Dolby Digital and Dolby Pro Logic II, and has a frequency response of 20-20,000 Hz.
Compatibility: The FireWave is listed as being compatible with Mac OS X version 10.4.6 (Tiger.) Officially, Griffin Technology does not support the FireWave under OS X 10.5.x (Leopard), however version 1.0 of the FireWave software does work with Leopard.
Griffin has announced the discontinuation of this product, so it is unlikely that Leopard-specific drivers will be released.
External links
FireWave product info page by Griffin Technology
Macintosh internals
Sound cards | FireWave | Technology | 354 |
53,554,252 | https://en.wikipedia.org/wiki/Octopussy%20%28software%29 | Octopussy, also known as 8Pussy, is a free and open-source computer-software which monitors systems, by constantly analyzing the syslog data they generate and transmit to such a central Octopussy server (thus often called a SIEM solution). Therefore, software like Octopussy plays an important role in maintaining an information security management system within ISO/IEC 27001-compliant environments.
Octopussy has the ability to monitor any device that supports the syslog protocol, such as servers, routers, switches, firewalls, load balancers, and its important applications and services. The main purpose of the software is to alert its administrators and users to different kinds of events, like system outages, attacks on systems or errors in applications. However, unlike Nagios or Icinga, Octopussy is not a state-checker and therefore problems cannot be resolved within the application. The software also makes no prescription whatsoever on which messages must be/must not be analyzed. As such, Octopussy can be seen as less powerful than other popular commercial software in the same category (event monitoring and log analysis).
Octopussy is compatible with many Linux system distributions like Debian, Ubuntu, OpenSUSE, CentOS, RHEL and even meta-distributions as Gentoo or Arch Linux. Although Octopussy was originally designed to run on Linux, it could be ported to other Unix variants like FreeBSD with minimal effort. Octopussy has extensive report generating features and also various interfaces to other software, like e.g. NSCA (Nagios), Jabber/XMPP and Zabbix. With the help of software like Snare even Windows EventLogs can be processed.
Octopussy is licensed under the terms of the GNU General Public License.
Characteristics
Although Octopussy is free and open-source software it has a variety of characteristics also found in some professional enterprise applications like Splunk, SAWMILL or Kiwi Syslog.
Octopussy features
At the time of writing, Octopussy comes with the following set of features:
Basic LDAP support (v1.0+) for Octopussy users and contacts with filter mechanism
Alert sending by email, IM (Jabber), NSCA (Nagios) and Zabbix
Map functionality to show the system infrastructure known to Octopussy
Exportable reports by email, FTP and SCP
Input & output plugins for manual and automatic reports
Report scheduling and automated report generation based on parameters
A log viewer to search for syslog messages received by Octopussy
An RRDtool to provide data graphing of syslog activity for enabled services
Comprehensive service definitions (Apache 2, BIND, BSD Kernel ...)
A wizard to easily create new services and/or message patterns for existing services
An option to enable or disable services and alerts for every system under surveillance
Online updates for services, tables and l18n (language support)
Multi-language support: English French German Italian Spanish Portuguese Russian
A web-interface for viewing current devices status, alerts, log messages, etc.
A themable interface and report documents
Manageability of Octopussy core services from the operating system shell
Flat-text formatted configuration files (integrates with many configuration editors)
An option to timely rotate and store received syslog messages in various locations
User management with the ability of granular permission configuration
Simple outline of styles and GUI components in ASP for easy modification
Supported services
Some of the (meta-)services supported by/known by Octopussy are:
Apache 2, BIND, BSD Kernel, BSD PAM, BSD System, Cisco Routers (ASR), Cisco Switches, ClamAV, DenyAll Reverse Proxy, DRBD, F5 BigIP, Fortinet FW, HP-Tools, Ironport MailServer, Juniper Netscreen FW, Juniper Netscreen NSM, LDAP, Linux AppArmor, Linux Auditd, Linux IPTables, Linux Kernel, Linux PAM, Linux System, Monit, MySQL, Nagios, Neoteris/Juniper FW, NetApp NetCache, Postfix, PostgreSQL, Samba, Samhain, SNMPd, Squid, SSHd, Syslog-ng, TACACS, VMware ESX(i), Windows Snare Agent, Windows System, Xen ...
Processible events
Events receivable from services and thus processible by Octopussy include:
Failed and/or successful logins, especially of higher privileged users
Violation of access permissions or policies in applications and operating systems
Write and/or read access in critical environments, e.g. with AppArmor or SELinux
Established or terminated VPN tunnels in systems, like e.g. Juniper Netscreen
Objects like processes or files which security context or configuration changed
Started or stopped processes on an operating system level
Critical system states like (unrecoverable) hardware or software failure
Change in operating system state due to boot, reboot or shutdown
Information regarding network connections/traffic, including ICMP messages, etc.
Detection or otherwise handling of malware (i.e. worms, viruses, trojans)
Dependencies
The software requires RSYSLOG installed on the syslog-server and expects systems that are monitored to run one of the numerous available syslog services, like e.g. syslogd/klogd, RSYSLOG or syslog-ng.
The software further depends on the Apache 2 HTTP Server installed, with Apache::ASP, Mod_Perl and Mod_SSL. Octopussy also requires a MySQL DBMS (actual database is installed/copied during Octopussy setup) as well as a recent Perl interpreter installed on the operating system, with a variety of Perl modules from CPAN (e.g. Crypt::PasswdMD5, DBD::mysql, JSON, Unix::Syslog, XML::Simple). A comprehensive list of those modules can be found within the software packages/archives README.txt file. In addition to that NSCD and RRDtool are a requirement. RRDtool aids in the creation of graphs that will be displayed on the Octopussy dashboard or shown on a per-device/per-service level.
Architecture
Octopussy receives syslog messages via syslog protocol and therefore behaves passively, not running any type of network agent on the remote machines under monitoring/surveillance. Octopussy completely conforms to RfC 3164 and RfC 3195 of the IETF, describing syslog as the logging mechanism in Unix-like/BSD operating systems. That especially includes the internal representation of the facility and severity-principle where applicable.
The software is driven by a semi-stateful event correlation engine. This means that the engine records and thus knows its internal state, but only uses it to some extent to link together logically related elements for the same device, in order to draw a conclusion (i.e. to generate an alert). In Octopussy the semi-stateful correlation engine, with its so called sliding window (a shifting window being the logical boundary of a number of events during a certain period of time), is capable of comparing known past events with present ones based on a limited number of comparative values.
Octopussy Dispatcher
The Octo-Dispatcher is the component used by the Octopussy software to receive syslog lines from RSYSLOG and dispatch them into device directories. Every device registered and activated within Octopussy gets its syslog messages assigned to it depending on the device name. Noteworthy is also the adjacent Octo-Replay component, which is the program used by the Octopussy software to replay log messages for some device or service (it receives and processes recognized logs and puts them back into the incoming directory).
Octopussy Parser
The Octo-Parser and Octo-Uparser are two of Octopussy's most important core components. The Octo-Parser is the program used by the Octopussy software to parse logs in syslog format for each device registered within Octopussy. It basically uses a regex-engine and commences pattern matching on incoming syslog messages. The Octo-Uparser is restarted every time device's services are changed, to check if previously received "unknown" log messages can be associated with a service.
In some cases Octo-Pusher is also called in advance to process non-syslog messages incoming from some devices. In that regard, the device setting "asynchronous" is helpful to process such log messages, after they were sent to an Octopussy server using e.g. FTP, rsync or SSH/SCP.
Octopussy Interface
The Octopussy interface (GUI) is the default user-interface and provides configuration management, device and service management as well as alert definition and therefore extends the Octopussy core components. Devices are displayed in tabular form on the Devices page, with the following descriptors as a minimum: hostname, IP address, log type, device model/type, FQDN and OS.
Hence, the interface (Octo-Web) mainly provides access to other Octopussy core components like Octo-Commander, Octo-Message-Finder, Octo-Reporter and Octo-Statistic-Reporter. The Octopussy front-end/GUI is written in Perl 5, employing Apache::ASP to structure and display content.
In addition to that, Octopussy core services can also be accessed from the operating system shell. That represents a convenient way for administrators to start/stop services or make fundamental configuration changes.
Octopussy RRD
The Octopussy RRD graph generator is a core component of the software and installed by default. Since the generation of such graphs is very resource intensive administrators may opt to disable it on an Octopussy syslog server with a less powerful CPU and a low amount of RAM. The generated RRD graphs displays the activity of all active services for monitored devices, highly depending on the specific service. After a restart of the Octopussy software or during operation, Octo-Dispatcher and Octo-Parser will always process syslog messages in their buffer and queue first and RRD graph generation is delayed. Octo-RRD further depends on Octo-Scheduler, to execute the Octopussy::Report function in order to generate syslog activity RRD graphs, that have been scheduled previously. Finally Octo-Sender has the capability to send report data to arbitrary recipients.
Extensions
There is a plug-in/module system in Octopussy, which is mainly geared towards the modification of Octopussy reports. Such a plug-in consists out of a description file, which defines the plug-in name and functions, and a code file with perl code to process the actual data.
There are also extensions for software related to Octopussy, like e.g. a Nagios plug-in that checks the Octopussy core services (i.e. Octo-Dispatcher, Octo-Scheduler, etc.) as well as the Octopussy parser states and log partitions.
Services & Patterns
The creation of new services and service patterns presents the most important way to extend Octopussy without making changes to the source code. However, since patterns are outlined as simplified regular expressions, administrators should have at least some basic knowledge about regex in general. It is further strongly recommended to build on already existing services and also understand the meaning of a message objects' basic fields, which are message ID, pattern, log level, taxonomy, table and rank.
Usually the logs wizard is used to search the system for unrecognized syslog messages per device to generate new service patterns. During the process the creation of patterns should be in a way that enables Octopussy to distinguish messages based on their severity and taxonomy.
See also
Log management and intelligence
Splunk – An enterprise log analysis software
Comparison of network monitoring systems
Web log analysis software
List of web analytics software
References
External links
Octopussy Documentation on GitHub
Computer logging
Free network management software
System monitors
Linux security software
System software
Unix security-related software
Internet Protocol based network software
System administration
Octopussy | Octopussy (software) | Technology | 2,527 |
13,790,160 | https://en.wikipedia.org/wiki/Zeta%20Cygni | Zeta Cygni (ζ Cyg) is a binary star system in the northern constellation of Cygnus, the swan. It has an apparent visual magnitude of 3.26 and, based upon parallax measurements, is about away.
The primary component, ζ Cyg A is a giant star with a spectral type of G8 IIIp. Its most likely status is as a red clump giant, an evolved star that has begun core helium fusion. It has around three times the mass of the Sun and has expanded to about 15 times the Sun's radius. It is radiating 112 times the brightness of the Sun from its outer atmosphere at an effective temperature of 4,910 K. At this temperature, the star glows with the yellow hue of a G-type star.
The secondary component, ζ Cyg B, is a white dwarf of type DA4.2. The pair orbit each other every 6,489 days (17.8 years) with an eccentricity of 0.22. The white dwarf cannot be seen directly, but is estimated to have an apparent magnitude of 13.2.
Zeta Cygni has an overabundance of barium, as well as other heavy chemical elements in its atmosphere, making it a so-called "mild" barium star. These elements were synthesized by the other member of the system as it passed through the asymptotic giant branch (AGB) stage of its evolution, then ejected in its stellar wind and accreted onto the current primary component. Prior to acquiring this additional mass, Zeta Cygni had about 2.5 times the mass of the Sun, while the more evolved AGB star had three solar masses.
References
External links
G-type giants
White dwarfs
Barium stars
Horizontal-branch stars
Spectroscopic binaries
Cygnus (constellation)
Cygni, Zeta
BD+29 4348
Cygni, 64
202109
104732
8115 | Zeta Cygni | Astronomy | 394 |
52,171,962 | https://en.wikipedia.org/wiki/Chitonomyces%20elegans | Chitonomyces elegans is a species of fungus in the family Laboulbeniaceae.
References
External links
Chitonomyces elegans at gbif.org
Laboulbeniaceae
Fungi described in 1926
Fungus species | Chitonomyces elegans | Biology | 49 |
26,031,935 | https://en.wikipedia.org/wiki/Technology%20scouting | Technology scouting is an element of technology management in which
(1) emerging technologies are identified,
(2) technology related information is channeled into an organization, and
(3) supports the acquisition of technologies.
It is a starting point of a long term and interactive matching process between external technologies and internal requirements of an existing organization for strategic purposes. This matching may also be aided by technology roadmapping. Technology scouting is also known to be part of competitive intelligence, which firms apply as a tool of competitive strategy. It can also be regarded as a method of technology forecasting or in the broader context also an element of corporate foresight. Technology scouting may also be applied as an element of an open innovation approach. Technology scouting is seen as an essential element of a modern technology management system.
The technology scout is either an employee of the company or an external consultant who engages in boundary spanning processes to tap into novel knowledge and span internal boundaries. They may be assigned part-time or full-time to the scouting task. The desired characteristics of a technology scout are similar to the characteristics associated with the technological gatekeeper. These characteristics include being a lateral thinker, knowledgeable in science and technology, respected inside the company, cross-disciplinary orientated, and imaginative personality. Technology scouts would also often play a vital role in a formalised technology foresight process.
Case studies
Documented case studies include:
See also
Corporate Foresight
Foresight (futures studies)
Futurology
Horizon scanning
Scientific lacuna
Strategic foresight
Technology Management
References
Scientific Journals
Technological Forecasting and Social Change
Futures
Futures & Foresight Science
Foresight
Journal of Futures Studies
Strategic management
Technological change
Technology forecasting
Technology assessment
fr:Veille technologique | Technology scouting | Technology | 341 |
5,011,479 | https://en.wikipedia.org/wiki/Evangelina%20Villegas | Evangelina Villegas (October 24, 1924 – April 24, 2017) was a Mexican cereal biochemist whose work with maize led to the development of quality protein maize (QPM). She and her colleague from the International Maize and Wheat Improvement Center (CIMMYT), Surinder Vasal, shared the 2000 World Food Prize for this achievement. Villegas was the first woman to ever receive the World Food Prize.
Education
Villegas did a B.A. chemistry and biology at the National Polytechnic Institute of Mexico and earned a M.Sc. on cereal technology from Kansas State University. She also earned a Ph.D. in cereal chemistry from the North Dakota State University.
Career
In 1950, Villegas became a chemist at the Instiuto Nacional de Nutriologia. She would also work as a librarian in the Office of Special Studies. Then in 1957, in this same office, she began work for the Wheat Industrial Quality Chemical Evaluation. A decade later, she would move to the International Maize and Wheat Improvement Center in Mexico (CIMMYT).
In the 1970s, Villegas would begin collaborative research with Vasal. Villegas was in charge of the lab investigating protein quality, while Vasal worked on developing QPM varieties that would gain widespread acceptance. Villegas and Vasal together combined existing "opaque-2" maize variety using molecular biology techniques. During this time, Villegas would be credited for the evaluation, development, and adaptation of a chemical methodology to screen large numbers of small samples for industrial wheat quality and maize nutritional and protein quality.
She would go on to be named Head of the General Service Laboratory in 1992, serve as a consultant for national programs for protein quality and industrial quality laboratories for Brazil, Argentina, and Guatemala. She would also be involved in the establishment of quality laboratories in India, Thailand, Egypt, Tunis, Ghana, the Philippines, Peru, Ecuador, Colombia, Bolivia, and Mexico.
Legacy
While at the CIMMYT, Villegas created a scholarship for the "birders" (men hired to keep birds away from the grain). This allowed the men to go and pursue an education that they otherwise would not have been able to.
After her retirement, Villegas became an advisor to the Sasakwa Africa Association, to help improve agricultural technology in Africa. She would also act as an advisor to young scientists.
The chemical and analytical approaches she developed continue to aid the CIMMYT in their work to monitor protein quality in QPM. In 2017, CMMIYT named a laboratory in her honor.
Awards and honors
(1972): Distinguished alumni award: National Polytechnic Institute of Mexico
(2000): Woman of the year: Mexico National Award
(2000): World Food Prize (shared with Surinder Vasal)
(2001): Lázaro Cárdenas Medal: National Polytechnic Institute of Mexico
(2001): Alpha Delta Kappa: International Women of Distinction
(2002): Doctor of Science (honoris causa): Chapingo Autonomous University
(2013): Distinguished alumni award: Kansas State University
Selected publications
Evangelina Villegas, Edwin Theodore Mertz. 1971. Chemical screening methods for maize protein quality at CIMMYT. Número 20 de Research bulletin - International Maize and Wheat Improvement Center. Editor CIMMYT, 14 pp.
Books
S. Twumasi-Afriyie, w. Haag, Evangelina Villegas. 1999. Quality protein maize in Ghana: A partnership in research, development, and transfer of technology. En: Breth, SA (ed.)
Enrique I. Ortega M., Reinald Bauer, Evangelina Villegas M. 1985. Métodos químicos usados en el CIMMYT para determinar la calidad de proteína de los cereales. 2ª edición de CIMMYT, 32 pp.
Evangelina Villegas, Enrique Ortega Martínez, Reinald Bauer. 1984. Chemical methods used at CIMMYT for determining protein quality in cereal grains. Editor Protein Quality Laboratory, International Maize and Wheat Improvement Center, 35 pp.
——. 1968. Variability in lysine content of wheat, rye and triticale proteins. Editor International Maize and Wheat Improvement Center, 32 pp.
——. 1967. Variability in lysine content of wheat, rye and triticale proteins. Editor Dakota State University. 158 pp.
——. 1963. The role of sulfhydryl groups in flour. Editor Kansas State University, 124 pp.
References
1924 births
2017 deaths
Mexican biochemists
Mexican women chemists
Scientists from Mexico City
21st-century Mexican women scientists
Women biochemists
20th-century Mexican women scientists
21st-century Mexican scientists
20th-century Mexican scientists
Mexican expatriates in the United States
Agriculture and food award winners | Evangelina Villegas | Chemistry | 974 |
22,601,981 | https://en.wikipedia.org/wiki/Pitfall%20trap | A pitfall trap is a trapping pit for small animals, such as insects, amphibians and reptiles. Pitfall traps are a sampling technique, mainly used for ecology studies and ecologic pest control. Animals that enter a pitfall trap are unable to escape. This is a form of passive collection, as opposed to active collection where the collector catches each animal (by hand or with a device such as a butterfly net). Active collection may be difficult or time-consuming, especially in habitats where it is hard to see the animals such as in thick grass.
Structure and composition
Pitfall traps come in a variety of sizes and designs. They come in two main forms: dry and wet pitfall traps. Dry pitfall traps consist of a container (tin, jar or drum) buried in the ground with its rim at surface level used to trap mobile animals that fall into it. Wet pitfall traps are basically the same, but contain a solution designed to kill and preserve the trapped animals. The fluids that can be used in these traps include formalin (10% formaldehyde), methylated spirits, alcohol, ethylene glycol, trisodium phosphate, picric acid or even (with daily checked traps) plain water. A little detergent is usually added to break the surface tension of the liquid to promote quick drowning.
The opening is usually covered by a sloped stone or lid or some other object. This is done to reduce the amount of rain and debris entering the trap, and to prevent animals in dry traps from drowning (when it rains) or overheating (during the day) as well as to keep out predators.
One or more fence-lines of some sort may be added to channel targets into the trap.
Traps may also be baited. Lures or baits of varying specificity can be used to increase the capture rate of a certain target species or group by placing them in, above or near the trap. Examples of baits include meat, dung, fruit and pheromones.
Uses
Pitfall traps can be used for various purposes:
During the mating seasons of toads, frogs and salamanders in temperate climates, these animals often have to cross busy roads on their way from wintering grounds to breeding ponds. To prevent them from being killed, volunteers may place low fences along roads which the animals have to cross. On short distances, dry pitfall traps are then placed along the fences to collect the animals, which subsequently are manually transferred to the other side of the road, thus preventing massive roadkill.
Collectors and researchers of various ground-dwelling arthropod species may use pitfall traps to collect the animals they are interested in. This can be done without bait (for example ground beetles and spiders) or with bait (for example dung beetles).
When used in series, these traps may also be used to estimate species richness (number of species present) and abundances (number of individuals), and this combined information may be used to calculate biodiversity indices (e.g. the Shannon index).
Disadvantages of pitfalls
There are inevitably biases in pitfall sampling when it comes to comparison of different groups of animals and different habitats in which the trapping occurs. An animal's trappability depends on the structure of its habitat (e.g. density of vegetation, type of substrate). Gullan and Cranston (2005) recommend measuring and controlling for such variations. Intrinsic properties of the animal itself also affect its trappability: some taxa are more active than others (e.g. higher physiological activity or ranging over a wider area), more likely to avoid the trap, less likely to be found on the ground (e.g. tree-dwelling species that occasionally move across the terrain), or too large to be trapped (or large enough to escape if trapped). Trappability can also be affected by conditions such as temperature or rain, which may alter the animal's behaviour. The capture rate is therefore proportional not only to how abundant a given type of animal is (which is often the factor of interest), but how easily they are trapped. Comparisons between different groups must therefore take into account variation in habitat structure and complexity, changes in ecological conditions over time and the innate differences in species.
See also
Insect collecting
Malaise trap
Flight Interception Trap (FIT)
Bottle trap
Quadrat
Bug zapper
References
Further reading
Gullan, P. J. and Cranston, P. S. (2005). The Insects: An Outline of Entomology. Malden, MA. Blackwell Publishing.
Entomology equipment
Zoology
Animal trapping
Fur trade
Environmental Sampling Equipment | Pitfall trap | Biology | 944 |
74,844,675 | https://en.wikipedia.org/wiki/Nanomaterials%20and%20cancer | Nanomaterials have gained significant attention in the field of cancer research and treatment due to their unique properties and potential applications. These materials, typically on the nanoscale (measuring less than 100 nanometers), offer several advantages in the fight against cancer.
Use in cancer treatment
Here are some ways nanomaterials are used in cancer treatment:
Drug delivery systems: Nanoparticles can be loaded with anticancer drugs, improving drug solubility, stability, and targeted delivery to cancer cells. This enhances the drug's therapeutic effect while reducing side effects on healthy tissues.
Photothermal therapy: Certain nanoparticles, like gold nanoparticles or carbon nanotubes, can absorb light and convert it into heat. This property is harnessed for photothermal therapy, where these particles are targeted to cancer cells and then heated with laser light, causing localized cell damage and cell death.
Photodynamic therapy: Nanoparticles can be used as carriers for photosensitizing agents. When exposed to light of a specific wavelength, these agents generate reactive oxygen species, which can kill cancer cells or damage their structural components.
MRI contrast agents: Nanomaterials with magnetic properties, such as iron oxide nanoparticles, are used as contrast agents in magnetic resonance imaging (MRI). They can help detect and visualize tumors with high precision.
Radiotherapy enhancers: Some nanoparticles, like high atomic number nanoparticles, can enhance the effects of radiation therapy. They increase the absorption of ionizing radiation, leading to improved tumor cell damage while sparing healthy tissue.
Diagnostic tools and medical factory: Quantum dots and other nanomaterials are used in cancer diagnostics. They can be designed to specifically target cancer biomarkers, allowing for highly sensitive and accurate detection of cancer cells or molecules associated with cancer.
Gene therapy: Nanocarriers, such as lipid nanoparticles or polymer nanoparticles, can deliver therapeutic genes to cancer cells. This approach aims to modify the genetic makeup of the cancer cells, either to inhibit their growth or sensitize them to other treatments.
Immunotherapy enhancement: Nanomaterials can be used to enhance the effectiveness of immunotherapies. They can serve as carriers for immune checkpoint inhibitors, vaccines, or other immunomodulatory agents.
Intracellular drug delivery: Some nanoparticles are designed to penetrate cancer cells and release therapeutic payloads directly into their interior. This can be especially valuable for targeting resistant or hard-to-reach cancer cells.
Personalized medicine: The versatility of nanomaterials allows for the development of personalized cancer therapies. Tailoring nanoparticle properties to match an individual's specific cancer type and genetic makeup can improve treatment outcomes.
Minimally invasive surgery: Nanomaterials can enable minimally invasive surgical techniques. Nanorobots or nanocapsules can be designed to perform precise procedures, such as tumor resection or drug delivery, with minimal damage to surrounding tissue.
While nanomaterials hold potential in cancer treatment, there are also challenges related to their safety, potential toxicity, and regulatory considerations. Extensive research and rigorous testing are required to ensure the efficacy and safety of these materials in clinical applications. The field of nanomedicine continues to evolve and holds potential for improving cancer diagnosis and treatment.
References
Cancer
Experimental cancer treatments | Nanomaterials and cancer | Materials_science | 696 |
192,399 | https://en.wikipedia.org/wiki/German%20aircraft%20carrier%20Graf%20Zeppelin | The German aircraft carrier Graf Zeppelin was the lead ship in a class of two carriers of the same name ordered by the Kriegsmarine of Nazi Germany. She was the only aircraft carrier launched by Germany and represented part of the Kriegsmarines attempt to create a well-balanced oceangoing fleet, capable of projecting German naval power far beyond the narrow confines of the Baltic and North Seas. The carrier would have had a complement of 42 fighters and dive bombers.
Construction on Graf Zeppelin began on 28 December 1936, when her keel was laid down at the Deutsche Werke shipyard in Kiel. Named in honor of Graf (Count) Ferdinand von Zeppelin, the ship was launched on 8 December 1938, and was 85% complete by the outbreak of World War II in September 1939. Graf Zeppelin was not completed and was never operational due to shifting construction priorities necessitated by the war. She remained in the Baltic for the duration of the war; with Germany's defeat imminent, the ship's custodian crew scuttled her just outside Stettin in March 1945. The Soviet Union raised the ship in March 1946, and she was ultimately sunk in weapons tests north of Poland 17 months later. The wreck was discovered by a Polish survey ship in July 2006.
Design
Graf Zeppelin was long overall; she had a beam of and a maximum draft of . At full combat load, she would have displaced . The ship's propulsion system consisted of four Brown, Boveri & Cie geared turbines with sixteen oil-fired, ultra-high-pressure LaMont boilers. The power plant was rated at and a top speed of . Graf Zeppelin had a projected cruising radius of at a speed of . She would have had a crew of 1760 officers and enlisted men, plus flight crews.
The ship's primary offensive power would have been its aircraft complement. Graf Zeppelin would have carried 42 aircraft as designed: 12 navalized Junkers Ju 87 "Stuka" dive bombers, 10 Messerschmitt Bf 109 fighters, and 20 Fieseler Fi 167 torpedo bombers. Later during the construction process, the aerial complement was reworked to consist of thirty Ju 87s and twelve Bf 109s, and the Fi 167s were removed altogether. As designed, Graf Zeppelin was to be fitted with eight 15 cm SK C/28 guns for defense against surface warships. This number was later increased to sixteen. Her anti-aircraft battery consisted of ten 10.5 cm SK C/33 guns—later increased to twelve—twenty-two 3.7 cm SK C/30 guns, and twenty-eight 2 cm guns. The ship's flight deck was protected with up to of Wotan Weich steel armor. A armored deck was located under the deck to protect the ship's vitals from aerial attacks. Graf Zeppelin had a waterline armor belt that was thick in the central area of the ship.
Construction and cancellation
On 16 November 1935, the contract for Flugzeugträger A (Aircraft carrier A)—later christened Graf Zeppelin—was awarded to the Deutsche Werke shipyard in Kiel. Construction of the ship was delayed since Deutsche Werke was working at capacity, and the slipway needed for Graf Zeppelin was occupied by the new battleship , which was launched on 8 December 1936. Work started on Graf Zeppelin on 28 December, when her keel was laid down. She was launched on 8 December 1938, the 24th anniversary of the Battle of the Falkland Islands, and she was christened by Helene von Zeppelin, the daughter of the ship's namesake. At the launching ceremony, Hermann Göring gave a speech. By the end of 1939, she was 85% complete, with a projected completion by the middle of 1940. By September 1939, one carrier-borne wing, Trägergruppe 186, had been formed by the Luftwaffe at Kiel Holtenau, composed of three squadrons equipped with Bf 109s and Ju 87s.
Meanwhile, the German conquest of Norway in April 1940 eroded any chance of completing Graf Zeppelin. Now responsible for defending Norway's long coastline and numerous port facilities, the Kriegsmarine urgently needed large numbers of coastal guns and anti-aircraft batteries. During a naval conference with Hitler on 28 April 1940, Admiral Erich Raeder proposed halting all work on Graf Zeppelin, arguing that even if she was commissioned by the end of 1940, final installation of her guns would need another ten months or more (her original fire-control system had been sold to the Soviet Union under an earlier trade agreement). Hitler consented to the stop work order, allowing Raeder to have Graf Zeppelins 15 cm guns removed and transferred to Norway. The carrier's heavy flak armament of twelve 10.5 cm guns had already been diverted elsewhere.
In July 1940, Graf Zeppelin was towed from Kiel to Gotenhafen (Gdynia) and remained there for nearly a year. While there, she was used as a storage depot for Germany's hardwood supply. Just before Germany invaded the Soviet Union in June 1941, the carrier was again moved, this time to Stettin, to safeguard her from Soviet air attacks. By November, the German army had pushed deep enough into Russian territory to remove any further threat of air attack and Graf Zeppelin was returned to Gotenhafen. There, she was used as a store ship for timber.
By the time Raeder met with Hitler for a detailed discussion of naval strategy in April 1942, the usefulness of aircraft carriers in modern naval warfare had been amply demonstrated. British carriers had crippled the Italian fleet at Taranto in November 1940, critically damaged the in May 1941 and prevented the battleship from attacking two convoys bound for Russia in March 1942. In addition, a Japanese carrier raid on Pearl Harbor had devastated the American battle fleet in December 1941. Raeder, anxious to secure air protection for the Kriegsmarines heavier surface units, informed Hitler that Graf Zeppelin could be finished in about a year, with another six months required for sea trials and flight training. On 13 May 1942, with Hitler's authorization, the German Naval Supreme Command ordered work resumed on the carrier.
But daunting technical problems remained. Raeder wanted newer planes, specifically designed for carrier use. Reichsmarshall Hermann Göring, head of the Luftwaffe, replied that the already overburdened German aircraft industry could not possibly complete the design, testing and mass production of such aircraft before 1946. Instead, he proposed converting existing aircraft (again the Junkers Ju 87 and Messerschmitt Bf 109) as a temporary solution until newer types could be developed. Training of carrier pilots at Travemünde would also resume.
The converted carrier aircraft were heavier versions of their land-based predecessors and this required a host of changes to Graf Zeppelins original design: the existing catapults needed modernization; stronger winches were necessary for the arresting gear; the flight deck, elevators and hangar floors also required reinforcement. Changes in naval technology dictated other alterations as well: installation of air search radar sets and antennas; upgraded radio equipment; an armored fighter-director cabin mounted on the main mast (which in turn meant a heavier, sturdier mast to accommodate the cabin's added weight); extra armoring for the bridge and fire control center; a new curved funnel cap to shield the fighter-director cabin from smoke; replacing the single-mount 20mm AA guns with quadruple Flakvierling 38 guns (with a corresponding increase in ammunition supply) to improve overall AA defense; and additional bulges on either side of the hull to preserve the ship's stability under all this added weight.
The German naval staff hoped all these changes could be accomplished by April 1943, with the carrier's first sea trials taking place in August that year. Towards that end, Chief Engineer Wilhelm Hadeler was reassigned to oversee Graf Zeppelins completion. Hadeler planned on getting the two inner shafts and their respective propulsion systems operational first, giving the ship an initial speed of 25–26 knots, fast enough for sea trials to commence and for conducting air training exercises. By the winter of 1943–1944 she was expected to be combat-ready.
On the night of 27–28 August 1942, while still moored at Gotenhafen, Graf Zeppelin was the target of the only Allied air attack aimed at her during the war. Three Royal Air Force Avro Lancaster heavy bombers from 106 Squadron were dispatched against the German aircraft carrier, each one carrying a single "Capital Ship" bomb, a device with a shaped charge warhead intended for armored targets. One pilot, who was unable to see the carrier due to haze, dropped his bomb instead on the estimated position of the Gneisenau. Another believed he had scored a direct hit on Graf Zeppelin, but there is no known record of the ship suffering any damage from a bomb strike that night.
On 5 December 1942, Graf Zeppelin was towed back to Kiel and placed in a floating drydock. It seemed she might well see completion after all, but by late January 1943 Hitler had become so disenchanted with the Kriegsmarine, especially with what he perceived as the poor performance of its surface fleet, that he ordered all of its larger ships taken out of service and scrapped. Raeder was relieved of command shortly thereafter and replaced with the Commander of Submarines Karl Dönitz. Though Dönitz eventually persuaded Hitler to void most of the order, work on all new surface ships and even those nearing completion, including Graf Zeppelin, was halted. On 30 January 1943, all major work on the ship ceased, though some limited, temporary work continued until March.
In April 1943 Graf Zeppelin was again towed eastward, first to Gotenhafen, then to the roadstead at Swinemünde and finally berthed at a back-water wharf in the Parnitz River, two miles (3 km) from Stettin, where she had been briefly docked in 1941. There she languished for the next two years with only a 40-man custodial crew in attendance. When Red Army forces neared the city in April 1945, the ship's Kingston valves were opened, flooding her lower spaces and settling her firmly into the mud in shallow water. A ten-man engineering squad then rigged the vessel's interior with demolition and depth charges in order to hole the hull and destroy vital machinery. At 6pm on 25 April 1945, just as the Soviets entered Stettin, commander Wolfgang Kähler radioed the squad to detonate the explosives. Smoke billowing from the carrier's funnel confirmed the charges had gone off, rendering the ship useless to her new owners for many months to come.
Fate after the war
The carrier's history and fate after Germany's surrender was unknown outside the Soviet Union for decades after the war. The Soviets could not repair the ship in the length of time specified by the terms of the Allied Tripartite Commission, so she was designated a "Category C" ship. This classification required that she would be destroyed or sunk in deep water by 15 August 1946. Instead, the Soviets decided to salvage the damaged ship and it was refloated in March 1946. A number of speculations from Western historians about the ship's fate arose in the decades after the end of the war. According to German historian Erich Gröner, after the Soviets raised the scuttled ship, they towed her to Leningrad. While en route, she reportedly struck a mine off Finland during a storm. Gröner claimed that after Graf Zeppelin arrived in Leningrad, she was broken up for scrap in 1948–1949. Naval historians Robert Gardiner and Roger Chesneau state that the ship was towed out of Stettin in September 1947, but she never arrived in Leningrad; they speculated that a mine sank the ship while she was under tow.
According to Soviet records, on 19 March 1947, the Council of Ministers decreed the destruction of former German ships. The first ship to be sunk, Lützow, was sunk off Swinemunde on 22 July 1947. On 14 August Graf Zeppelin was towed into Swinemunde harbor, and two days later to its final position. It was subjected to five series of controlled explosions of shells and FAB series bombs. The first test imitated a FAB-1000 detonation in the exhaust funnel and lesser bombs below the flight deck. The second in the series was a single FAB-1000 explosion above the flight deck. The third, the fourth and the fifth series imitated penetration of FAB-100, FAB-250 and FAB-500 bombs at flight deck, hangar deck and gun battery deck levels. These bombs were placed in cutouts in their target decks to imitate the effects of dive bombing. Graf Zeppelin remained afloat, and Admiral Yury Rall ordered a torpedo strike. A torpedo fired from an Elco PT boat exploded in the anti-torpedo bulge but did not penetrate the belt armor. A torpedo fired by the destroyer Slavny penetrated the unprotected hull section below the bow elevator; Graf Zeppelin sank 25 minutes later.
Discovery in 2006
The exact position of the wreck was unknown for decades. On 12 July 2006, the research vessel , a ship belonging to the Polish oil company Petrobaltic, found a wreck north of Władysławowo, which they thought was most likely Graf Zeppelin. The wreck rests at a depth of more than below the surface. After the wreck was located, the Polish Navy began a two-day survey of the wreckage to confirm its identity. Using remote-controlled underwater robots, they concluded that they were "99% certain" it was Graf Zeppelin.
Notes
Footnotes
Citations
References
Further reading
External links
Launching Ceremony of the Graf Zeppelin
Graf Zeppelin-class aircraft carriers
World War II aircraft carriers of Germany
Shipwrecks in the Baltic Sea
Proposed aircraft carriers
Germany–Soviet Union relations
1938 ships
Maritime incidents in April 1945
Maritime incidents in 1947
Ships sunk as targets
Proposed ships of Germany
Ships built in Kiel
Shipwrecks of Poland | German aircraft carrier Graf Zeppelin | Engineering | 2,838 |
3,288,669 | https://en.wikipedia.org/wiki/Rudolphine%20Tables | The Rudolphine Tables () consist of a star catalogue and planetary tables published by Johannes Kepler in 1627, using observational data collected by Tycho Brahe (1546–1601). The tables are named in memory of Rudolf II, Holy Roman Emperor, in whose employ Brahe and Kepler had begun work on the tables. The main purpose of the Rudolphine tables was to allow the computation of the positions of the then known planets of the Solar System, and they were considerably more precise than earlier such tables.
Previous tables
Star tables had been produced for many centuries and were used to establish the position of the planets relative to the fixed stars (particularly the twelve constellations used in astrology) on a specific date in order to construct horoscopes. Until the end of the 16th century, the most widely used had been the Alphonsine tables, first produced in the 13th century and regularly updated thereafter. These were based on a Ptolemaic, geocentric model of the Solar System. Although the Alphonsine tables were not very accurate, nothing else was available and so they continued to be used.
In 1551, following the publication of De revolutionibus orbium coelestium by Nicholas Copernicus, Erasmus Reinhold produced the Prutenic Tables based on a heliocentric model of the Solar System, but these were no more accurate than the earlier tables.
Observations and prelude
The observations underlying the Rudolphine tables were performed by Tycho Brahe and his team. Brahe's measurements were much more accurate than the ones available previously. He worked with elaborate instruments to determine the precise positions of planets and stars in the sky but did not have a telescope.
Brahe had been supported by the Danish king Frederick II and had built an observatory on the island of Hven during 1576–1596. When the king died, Brahe moved to Prague and became the official imperial astronomer of Emperor Rudolf II. There he was joined by Kepler in 1600, and Rudolf instructed them to publish the tables. While Tycho Brahe favored a geo-heliocentric model of the solar system in which the Sun and Moon revolve around the Earth and the planets revolve around the Sun, Kepler argued for a Copernican heliocentric model.
When Tycho Brahe died in 1601, Kepler became the official imperial mathematician. By studying Brahe's data, he found his three laws of planetary motion, which he published in 1609 and 1619. Emperor Rudolf died in 1612 and Kepler left Prague.
Composition and publication
The tables were anticipated for many years, with pleas for its publication reaching as far as India and Jesuit missionaries in China. Apart from external hindrances, Kepler himself refrained from such a monumental enterprise involving endless tedious calculations. He wrote in a letter to a Venetian correspondent, impatiently inquiring after the tables: "I beseech thee, my friends, do not sentence me entirely to the treadmill of mathematical computations, and leave me time for philosophical speculations which are my only delight". They were finally completed near the end of 1623.
In his attempts to finance the printing of the tables, Kepler began by claiming the arrears due to him by Rudolph. From the Imperial Court in Vienna he was sent to three other towns to which the debt was transferred. After a year of roaming the country, he was eventually able to raise 2000 florins (out of 6299 owed to him), which sufficed to pay for the paper. He paid for the printing out of his own pocket. It was initially supposed to be printed in Linz, where he resided at the time, but the chaos of the Thirty Years' War (first the garrisoning of soldiers in the town, after which a siege of the revolting peasantry, which almost resulted in the burning of the manuscript) prompted him to leave. He began the enterprise anew in Ulm. There, after many quarrels with the printer Jonas Saur, the first edition of a thousand copies was completed in September 1627, in time for the annual book mart in the Frankfurt Fair.
While publishing the Rudolphine Tables, Kepler was hard-pressed to fight off Tycho's numerous relatives. During the publication process, these relatives repeatedly tried to obtain control of the observations and the profit from the publication of the tables.
Tycho had intended to dedicate the tables to Emperor Rudolf II, but by 1627, when the tables were published, Rudolf II had been dead for 15 years, so instead the tables were dedicated to Emperor Ferdinand II but are named after Rudolph II.
Contents
The book, written in Latin, contains tables for the positions of the 1,005 stars measured by Tycho Brahe, and more than 400 stars from Ptolemy and Johann Bayer, with directions and tables for locating the moon and the planets of the Solar System. Included are function tables of logarithms (a useful computational tool that had been described in 1614 by John Napier) and antilogarithms, and instructive examples for computing planetary positions.
For most stars these tables were accurate to within one arc minute, and included corrective factors for atmospheric refraction.
A map of the world was also included. A scroll in the lower left panel of the map is inscribed with instructions on how to use the map and a lunar distance measurement to calculate longitude: it states that by observing the edge of the Moon's disc in relation to a known star, or a lunar eclipse, it is possible to calculate longitude at the point of observation by calculating local time and comparing it to the time stated in the tables. For this purpose, Kepler needed his map to be as up-to-date as possible, and it is remarkable for being one of the first to show the Dutch discoveries of the west coast of Australia, Eendracht Land and Dedels Land; this information was apparently taken from the Nova Totius Terrarum Orbis Geographica ac Hydrographica Tabula by Jodocus Hondius II, published in Amsterdam in 1625. Hondius derived his geographical knowledge of Australia from the unpublished 1622 map of the Indian Ocean by Hessel Gerritz. A time scale along the Equator on Kepler's map indicates the hours to be added or subtracted for determining longitude (one hour equals 15 degrees longitude).
Use of the tables
The tables were sufficiently accurate to predict a transit of Mercury observed by Pierre Gassendi in 1631 and a transit of Venus observed by Jeremiah Horrox in 1639.
Adam Schall von Bell, a Jesuit in China, used the tables to complete a reform of the Chinese calendar in 1635.
See also
Ferdinand Verbiest - Astronomy contests
Star cartography
Urania Propitia
References
Bibliography
Robert J. King, “Johannes Kepler and Australia”, The Globe, no.90, 2021, pp.15-24.
External links
Universitätsbibliothek Kiel – Digiport: Tabulæ Rudolphinæ - Bartsch version from 1627, with appendices on Schiller's Christian constellations and Bartsch'es own constellation innovations.
Tabulæ Rudolphinæ from the NOAA Central Library, in PDF and TIFF formats.
Johannes Kepler, Tabulæ Rudolphinæ archive.org, frontispiece, world map, first half is explanation, second half is tables
Tabvlæ Rudolphinæ qvibvs astronomicæ scientiæ ... Typis J. Saurii, 1627. From the Rare Book and Special Collections Division at the Library of Congress
17th-century books in Latin
1627 books
Star atlases
Astronomical catalogues
Astrological texts
Tycho Brahe
1627 in science
Works by Johannes Kepler
Astronomical tables
Rudolf II, Holy Roman Emperor | Rudolphine Tables | Astronomy | 1,586 |
19,523,040 | https://en.wikipedia.org/wiki/Archaeol | Archaeol is a diether composed of two phytanyl chains linked to the sn-2 and sn-3 positions of glycerol. As its phosphate ester, it is a common component of the membranes of archaea.
Structure and contrast with other lipids
The 2,3-sn-glycerol structure and ether bond linkage are two key differences between lipids found in archaea vs those of bacteria and eukarya. The latter use 1,2-sn-glycerol, and mostly, ester bonds. Natural archaeol has 3R, 7R, 11R configurations for the three chiral centers in the isoprenoid chains. There are four structural variations, contributing to the complexity of the membrane lipids in function and properties. The two phytanyl chains can form a 36-member ring to yield macrocyclic archaeol. Hydroxylated archaeol has phytanyl chains hydroxylated at the first tertiary carbon atom, while sesterterpanyl archaeol have the phytanyl side chains with C25 sesterterpanyl chains, substituting at C2 of glycerol or at both carbons. Unsaturated archaeol, with the same carbon skeleton as standard archaeol but one or multiple double bonds in the phytanyl side chains is also discovered.
Biological role and synthesis
Two archaeol molecules can undergo head-to-head linkage to form caldarchaeol (one typical glycerol dialkyl glycerol tetraether, GDGT), one of the most common tetraether lipid in archaea.
Biological role
Archaeol has been found in all archaea so far, at least in trace amounts. It represents 100% of the diether core lipids in most neutrophilic halophiles and sulfur-dependent thermophiles (though their most core lipids are tetraether lipids). Methanogens contain hydroxyarchaeol and macrocyclic other than the standard archaeol, and sesterterpanyl-chain-containing archaeol is characteristic of alkaliphilic extreme halophiles. It is noteworthy that tetraether lipids are also widely present in archaea.
Liposomes (a spherical vesicle having at least at least one lipid bilayer) of lipids from archaea typically demonstrate extremely low permeability for molecules and ions, even including protons. The ion permeability induced by ionophores (ion transporters across the membranes) are also quite low, and only comparable to that of egg phosphatidylcholine (a very common biological membrane component) at 37˚C when the temperature rises up to c.a. 70˚C. Compared to bacteria and eukarya, the isoprenoid side chains of archaeol are highly branched. This structural difference is believed lower the permeability of archaea over the whole growth temperature range which enables archaea to adapt to extreme environments.
Biosynthesis
Archaeol's biosynthesis proceeds by a multistep process mediated by several enzymes. In simplified terms, glycerol 1-phosphate is etherified to two geranylgeranyl substituents contributed by geranylgeranyl pyrophosphate. The double bonds are reduced by nicotinamide and flavins. The phosphate group is subject to modification.
Archaea utilize biosynthetic pathways of isoprenoids that is distinct compared to bacteria and eukarya. The C5 precursors to the geranylgeranyl chains are isopentenyl pyrophosphate (IPP) and dimethylallyl pyrophosphate (DMAPP), which are produced by modified mevalonic acid pathway.
Ether lipids in bacteria
Though archaeol, featuring the ether linkage between isoprenoid chain to glycerol, has been considered as a biomarker for archaea, ether membrane lipids have also been discovered in some aerobic and anaerobic bacteria, including lipids with one ester bond and one ether bond to alkyl chains. Many strictly anoxic bacteria and a few aerobic species contain plasmalogens (Pla), which has an alkyl chain bound to sn-1 position of the glycerol via a vinyl-ether bond. Similar to archaea, these lipids are thought to increase the resistivity of bacteria to adverse environments. More stunning is the discovery of nonisoprenoid dialkyl glycerol diether lipids(DGD) and branched dialkyl glycerol tetraether lipids (brGDGT), which are formed, in the similar way to archaeol, by binding alkyls chains (but not isoprenoid chains) to glycerol molecules via ether linkage. It's highly notable that these lipids are only different from archaea ether lipids in the side chains and binding positions on the glycerol. DGD is reported in thermophilic bacteria, a few mesophilic bacteria and aggregating myxobacteria.
In 2018, a group from the University of Groningen managed to produce a large amount (30% of total phospholipids) of true archaeol-based phospholipid in transgenic E. coli. They found that the modified cells show higher tolerance to heat and cold. The result builds on top of their earlier 2015 attempt, which produced only a minuscule amount.
Used as a lipid biomarker
Archaeol in the sediments typically originates from the hydrolysis of archaea membrane phospholipids during diagenesis. Due to its high preservation potential, it is often detected and used by organic geochemists as a biomarker for archaea activity, especially for methanogen biomass and activity. As a methanogen proxy, it is used by Michinari Sunamura et al. to directly measure the methanogens in the sediments of Tokyo Bay, and also used by Katie L. H. Lim et al. as an indicator of methanogenesis in water-saturated soils. C. A. McCartney et al. used it as a proxy for methane production in cattle.
In the meantime, it's also used to help understand ancient biogeochemistry. It was used as a biomarker by Richard D. Pancost et al. in order to reconstruct the Holocene biogeochemistry in ombrotrophic peatlands. A pilot study led by Ian D. Bull et al. also used archaeol as a biomarker to reveal the differences between fermenting digestive systems in foregut and hindgut of ancient herbivorous mammals.
Additionally, because of different degradation kinetics of intact archaeol and caldarchaeol, the ratio of archaeol to caldarchaeol was proposed as a salinity proxy in highland lakes, providing a tool for paleosalinity studies.
Archaeol can also get hydrolyzed in some cases, with its side chains preserved as phytane or pristane, depending on the redox conditions.
Measurement
To analyze archaeol, lipids are commonly extracted via the traditional Bligh-Dyer procedure, usually followed by fractionation (by thin layer or column chromatography) and derivatization. Kazuhiro Demizu et al. and Sadami Ohtsubo et al. proposed similar processes involving acid Bligh and Dyer extraction, acid treatment and derivatization, with the core lipids finally being subjected to chromatography.
To determine the concentration of archaeol present in a sample, chromatography technologies are commonly employed, including high-performance liquid chromatography (HPLC), gas chromatography (GC), and supercritical fluid chromatography (SFC), with mass spectrometry (MS) often applied to aid the identification.
See also
Diacylglycerol
Caldarchaeol
:id:Archaeol
References
Lipids
Ethers | Archaeol | Chemistry | 1,729 |
33,066,456 | https://en.wikipedia.org/wiki/Dynamic%20Adaptive%20Streaming%20over%20HTTP | Dynamic Adaptive Streaming over HTTP (DASH), also known as MPEG-DASH, is an adaptive bitrate streaming technique that enables high quality streaming of media content over the Internet delivered from conventional HTTP web servers. Similar to Apple's HTTP Live Streaming (HLS) solution, MPEG-DASH works by breaking the content into a sequence of small segments, which are served over HTTP. An early HTTP web server based streaming system called SProxy was developed and deployed in the Hewlett Packard Laboratories in 2006. It showed how to use HTTP range requests to break the content into small segments. SProxy shows the effectiveness of segment based streaming, gaining best Internet penetration due to the wide deployment of firewalls, and reducing the unnecessary traffic transmission if a user chooses to terminate the streaming session earlier before reaching the end. Each segment contains a short interval of playback time of content that is potentially many hours in duration, such as a movie or the live broadcast of a sport event. The content is made available at a variety of different bit rates, i.e., alternative segments encoded at different bit rates covering aligned short intervals of playback time. While the content is being played back by an MPEG-DASH client, the client uses a bit rate adaptation (ABR) algorithm to automatically select the segment with the highest bit rate possible that can be downloaded in time for playback without causing stalls or re-buffering events in the playback. The current MPEG-DASH reference client dash.js offers both buffer-based (BOLA) and hybrid (DYNAMIC) bit rate adaptation algorithms. Thus, an MPEG-DASH client can seamlessly adapt to changing network conditions and provide high quality playback with few stalls or re-buffering events.
MPEG-DASH is the first adaptive bit-rate HTTP-based streaming solution that is an international standard. MPEG-DASH should not be confused with a transport protocol — the transport protocol that MPEG-DASH uses depends on which version of HTTP is used: TCP over HTTP and HTTP/2, or UDP over HTTP/3. MPEG-DASH uses existing HTTP web server infrastructure that is used for delivery of essentially all World Wide Web content. It allows devices like Internet-connected televisions, TV set-top boxes, desktop computers, smartphones, tablets, etc. to receive multimedia content (video, TV, radio, etc.) delivered via the Internet, coping with variable Internet receiving conditions. Standardizing an adaptive streaming solution is meant to provide confidence to the market that the solution can be adopted for universal deployment, compared to similar but more proprietary solutions like Smooth Streaming by Microsoft, or HDS by Adobe. Unlike HDS, or Smooth Streaming, DASH is codec-agnostic, which means it can use content encoded with any coding format, such as H.265, H.264, VP9, etc.
Standardization
MPEG-DASH technology was developed under MPEG. Work on DASH started in 2010; it became a Draft International Standard in January 2011, and an International Standard in November 2011. The MPEG-DASH standard was published in April, 2012 but has been revised in 2019 and then once more in 2022 as .
DASH is a technology related to Adobe Systems HTTP Dynamic Streaming, Apple Inc. HTTP Live Streaming (HLS) and Microsoft Smooth Streaming. DASH is based on Adaptive HTTP streaming (AHS) in 3GPP Release 9 and on HTTP Adaptive Streaming (HAS) in Open IPTV Forum Release 2. As part of their collaboration with MPEG, 3GPP Release 10 has adopted DASH (with specific codecs and operating modes) for use over wireless networks.
The DASH Industry Forum (DASH-IF) further promotes and catalyzes the adoption of MPEG-DASH and helps transition it from a specification into a real business. It consists of major streaming and media companies, including Microsoft, Netflix, Google, Ericsson, Samsung, Adobe, etc. and creates guidelines on the usage of DASH for different use cases in practice.
MPEG-DASH is integrated in other standards, e.g. MPEG-DASH is supported in HbbTV (as of Version 1.5).
Overview
DASH is an adaptive bitrate streaming technology where a multimedia file is partitioned into one or more segments and delivered to a client using HTTP. A media presentation description (MPD) describes segment information (timing, URL, media characteristics like video resolution and bit rates), and can be organized in different ways such as SegmentList, SegmentTemplate, SegmentBase and SegmentTimeline, depending on the use case. Segments can contain any media data, however the specification provides specific guidance and formats for use with two types of containers: ISO base media file format (e.g. MP4 file format) or MPEG-2 Transport Stream.
DASH is audio/video codec agnostic. One or more representations (i.e., versions at different resolutions or bit rates) of multimedia files are typically available, and selection can be made based on network conditions, device capabilities and user preferences, enabling adaptive bitrate streaming and QoE (Quality of Experience) fairness. DASH standard does not specify the adaptive bitrate streaming (ABR) logic. DASH is also agnostic to the underlying application layer protocol. Thus, DASH can be used with any protocol, e.g., DASH over CCN.
On July 27, 2015, MPEG LA announced a call for MPEG-DASH-related patents in order to create a single patent pool for this technology. MPEG LA announced its MPEG-DASH patent portfolio licence. MPEG-LA claims that the included patents are essential to the MPEG Dynamic Adaptive Streaming over HTTP standard.
Implementations
MPEG-DASH is available natively on Android through the ExoPlayer, on Samsung Smart TVs 2012+, LG Smart TV 2012+, Sony TV 2012+, Philips NetTV 4.1+, Panasonic Viera 2013+ and Chromecast. YouTube as well as Netflix already support MPEG-DASH, and different MPEG-DASH players are available.
While MPEG-DASH isn't directly supported in HTML5, there are JavaScript implementations of MPEG-DASH which allow using MPEG-DASH in web browsers using the HTML5 Media Source Extensions (MSE). There are also JavaScript implementations such as the bitdash player which support DRM for MPEG-DASH using the HTML5 Encrypted Media Extensions. In combination with WebGL, the HTML5-based adaptive bitrate streaming of MPEG-DASH enables also the efficient streaming of 360° video for live and on-demand use cases.
Clients and libraries
Shaka Player, is the open source DASH HTML5 video player from Google for Low Bandwidth Connections.
VLC media player 3.0 shipped a new client plugin for MP4/MPEG and Live streams.
The cross-platform FOSS multimedia framework GStreamer has supported MPEG-DASH and WebM DASH since at least v1.4.
The open-source library libdash is platform independent and runs on mobile platforms such as Android, iOS, Windows Phone.
bitmovin provides the bitdash MPEG-DASH player for HTML5 and Flash.
VideoJS is an open-source HTML5 video player, supports HLS, DASH, WebM, and progressive MP4 for Live and VOD streaming.
Clappr is an open-source HTML5 video player, uses HTMLVideoElement, supports DASH, HLS, progressive, ad insertion, dynamic overlays, picture-in-picture
Servers
Note that no specific support is required from the server for DASH content, with the exception of Live Streaming.
Wowza Streaming Engine has support MPEG-DASH playback with DVR and provides DASH Stream Target publishing to Akamai.
Brightcove Zencoder has support for MPEG-DASH transmuxing/transcoding.
Elemental Technologies video processing solutions support DASH.
Helix Universal Server has support for DASH in various modes.
Nimble Streamer has live and VOD MPEG-DASH support. For VOD it supports both H.265 and H.264 codecs
Unified Origin supports MPEG-DASH.
Services
Akamai CDN supports DASH.
Amazon CloudFront CDN supports DASH.
Amazon Web Services Elastic Transcoder has support for MPEG-DASH.
Azure Media Services platform has support for MPEG-DASH.
Bitmovin provides the cloud-based transcoding service bitcodin.com which supports MPEG-DASH.
CloudFlare Stream supports transcoding into DASH in VP9 before serving to the end user.
Cloudinary provides automatic transcoding with support for MPEG-DASH.
Lumen CDN supports DASH.
Limelight Networks CDN supports DASH.
Project Shield CDN supports DASH.
Tata Communications CDN supports DASH.
DogalZeka MS2 Alarm Monitoring, Transcoding and Recording DASH input/output support.
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Network protocols | Dynamic Adaptive Streaming over HTTP | Technology | 2,159 |
9,901,652 | https://en.wikipedia.org/wiki/Polio%20eradication | Polio eradication, the goal of permanent global cessation of circulation of the poliovirus and hence elimination of the poliomyelitis (polio) it causes, is the aim of a multinational public health effort begun in 1988, led by the World Health Organization (WHO), the United Nations Children's Fund (UNICEF) and the Rotary Foundation. These organizations, along with the U.S. Centers for Disease Control and Prevention (CDC) and The Gates Foundation, have spearheaded the campaign through the Global Polio Eradication Initiative (GPEI). Successful eradication of infectious diseases has been achieved twice before, with smallpox in humans and rinderpest in ruminants.
Prevention of disease spread is accomplished by vaccination. There are two kinds of polio vaccine—oral polio vaccine (OPV), which uses weakened poliovirus, and inactivated polio vaccine (IPV), which is injected. OPV is less expensive and easier to administer, and can spread immunity beyond the person vaccinated, creating contact immunity. It has been the predominant vaccine used. However, under conditions of long-term vaccine virus circulation in under-vaccinated populations, mutations can reactivate the virus to produce a polio-inducing strain, while OPV can also, in rare circumstances, induce polio or persistent asymptomatic infection in vaccinated individuals, particularly those who are immunodeficient. IPV, being inactivated, does not carry these risks, but does not induce contact immunity. IPV is more costly and the logistics of its delivery are more challenging.
Nigeria is the latest country to have officially stopped endemic transmission of wild poliovirus, with its last reported case in 2016. Of the three strains of WPV, the last recorded wild case caused by type2 (WPV2) was in 1999, and WPV2 was declared eradicated in 2015. Type3 (WPV3) is last known to have caused polio in 2012, and was declared eradicated in 2019. All wild-virus cases since that date have been due to type1 (WPV1).
, Afghanistan and Pakistan are the only two countries where the disease is still classified as endemic. Recent polio cases arise from two sources, the original "wild" poliovirus (WPV), and the much more prevalent mutated oral vaccine strains, known as circulating vaccine-derived poliovirus (cVDPV) or variant poliovirus. Vaccines against each of the three wild strains of polio have given rise to strains of cVDPV, with cVDPV2 being most prominent. cVDPV caused 524 confirmed paralytic polio cases worldwide in 2023, and was detected in 32 countries.
Factors influencing eradication of polio
Eradication of polio has been defined in various ways:
As elimination of the occurrence of poliomyelitis even in the absence of human intervention.
As extinction of poliovirus, such that the infectious agent no longer exists in nature or in the laboratory.
As control of an infection to the point at which transmission of the disease ceased within a specified area.
As reduction of the worldwide incidence of poliomyelitis to zero as a result of deliberate efforts, and requiring no further control measures.
In theory, if the right tools were available, it would be possible to eradicate all infectious diseases that reside only in a human host. In reality, there are distinct biological features of the organisms and technical factors of dealing with them that make their potential eradicability more or less likely. Three indicators, however, are considered of primary importance in determining the likelihood of successful eradication: that effective interventional tools are available to interrupt transmission of the agent, such as a vaccine; that diagnostic tools, with sufficient sensitivity and specificity, be available to detect infections that can lead to transmission of the disease; and that humans are required for the life-cycle of the agent, which has no other vertebrate reservoir and cannot amplify in the environment.
Strategy
The most important step in eradication of polio is interruption of endemic transmission of poliovirus. Stopping polio transmission has been pursued through a combination of routine immunization, supplementary immunization campaigns, and surveillance of possible outbreaks. Several key strategies have been outlined for stopping polio transmission:
High infant immunization coverage with four doses of oral polio vaccine (OPV) in the first year of life in developing and endemic countries, and routine immunization with OPV or IPV elsewhere.
Organization of "national immunization days" to provide supplementary doses of oral polio vaccine to all children less than five years old.
Active surveillance for poliovirus through reporting and laboratory testing of all cases of acute flaccid paralysis. Acute flaccid paralysis (AFP) is a clinical manifestation of poliomyelitis characterized by weakness or paralysis and reduced muscle tone without other obvious cause (e.g., trauma) among children less than fifteen years old. Other pathogenic agents can also cause AFP, such as enteroviruses, echoviruses, and adenoviruses.
Expanded environmental surveillance to detect the presence of poliovirus in communities. Sewage samples are collected at regular and random sites and tested in laboratories for the presence of WPV or cVDPV. Since most polio infections are asymptomatic, transmission can occur in spite of the absence of polio-related AFP cases, and such monitoring helps to evaluate the degree to which virus continues to circulate in an area.
Targeted "mop-up" campaigns once poliovirus transmission is limited to specific geographical foci.
Vaccination
There are two distinct types of polio vaccine. Oral polio vaccine (OPV, or Sabin vaccine) contains attenuated poliovirus. OPV is delivered as oral drops or infused into sugar cubes. It is highly effective and inexpensive (about per dose in 2024) and its availability has bolstered efforts to eradicate polio. The vaccine confers long-term, possibly lifelong, immunity to the virus. Because of its route of administration, it induces an immunization of the intestinal mucosa that protects against subsequent infection, though multiple doses are necessary to achieve effective prophylaxis. Attenuated poliovirus derived from the oral polio vaccine is excreted, infecting and indirectly inducing immunity in unvaccinated individuals, and thus amplifying the effects of the doses delivered. The oral administration does not require special medical equipment or training. Taken together, these advantages have made it the favored vaccine of many countries, and it has long been preferred by the global eradication initiative.
The primary disadvantage of OPV derives from its inherent nature. As an attenuated but active virus, it can induce vaccine-associated paralytic poliomyelitis (VAPP) in approximately one individual per every 2.7million doses administered. The live virus can circulate in under-vaccinated populations (circulating vaccine-derived poliovirus, cVDPV) and over time can revert to a neurovirulent form causing paralytic polio. Until recent times, a trivalent OPV containing all three virus strains was used, but with the eradication of wild poliovirus type2 this was phased out in 2016 and replaced with bivalent vaccine containing just types 1 and 3, supplemented with monovalent type2 OPV in regions with documented cVDPV2 circulation. A novel OPV2 vaccine (nOPV2) genetically modified to reduce the likelihood of disease-causing activating mutations was granted emergency licencing in 2021, and subsequently full licensure in December 2023. Genetically stabilsed vaccines targeting poliovirus types 1 and 3 are in development, with the intention that these will eventually completely replace the Sabin vaccines.
The inactivated polio vaccine (IPV, or Salk) contains trivalent fully inactivated virus, administered by injection. This vaccine cannot induce VAPP nor do cVDPV strains arise from it, but it likewise cannot induce contact immunity and thus must be administered to every individual. Added to this are greater logistical challenges. Though a single dose is sufficient for protection, administration requires medically trained vaccinators armed with single-use needles and syringes. Taken together, these factors result in substantially higher delivery costs. Original protocols involved intramuscular injection in the arm or leg, but recently subcutaneous injection using a lower dose (so-called fractional-dose IPV, fIPV) has been found to be effective, lowering costs and also allowing for more convenient and cost-effective delivery systems. The use of IPV results in serum immunity, but no intestinal immunity arises. As a consequence, vaccinated individuals are protected from contracting polio, but their intestinal mucosa may still be infected and serve as a reservoir for the excretion of live virus. For this reason, IPV is ineffective at halting ongoing outbreaks of WPV or cVDPV, but it has become the vaccine of choice for industrialized, polio-free countries.
While IPV does not itself induce mucosal immunity, it has been shown to boost the mucosal immunity from OPV, and the WHO now favors a combined protocol. It is recommended that vulnerable children receive a dose of OPV at birth, then beginning at the age of six weeks a 'primary series' consisting of three OPV doses at least four weeks apart, along with one dose of IPV after 14 weeks. This combined IPV/OPV approach has also been used in outbreak suppression.
Herd immunity
Polio vaccination is also important in the development of herd immunity. For polio to occur in a population, there must be an infecting organism (poliovirus), a susceptible human population, and a cycle of transmission. There is no animal reservoir for poliovirus, and the transmission cycle of polio is from one infected person to another person susceptible to the disease, usually through the fecal-oral route. If the vast majority of the population is immune to a particular agent, the ability of that pathogen to infect another host is reduced; the cycle of transmission is interrupted, and the pathogen cannot reproduce and dies out. This concept, called community immunity or herd immunity, is important to disease eradication, because it means that it is not necessary to inoculate 100% of the population—a goal that is often logistically very difficult—to achieve the desired result. If the number of susceptible individuals can be reduced to a sufficiently small number through vaccination, then the pathogen will eventually die off.
Herd immunity is an important supplement to vaccination. According to the concept of herd immunity, the population for whom the vaccine fails is still protected by the immunity of those around them, and it can only be achieved when vaccination levels are high. It is estimated that the minimum herd immunity threshold for poliovirus eradication ranges from approximately 75% in wealthy high-hygiene populations to 97% in poorer environments. If routine immunization were to be stopped, the number of unvaccinated, susceptible individuals would soon exceed the capability of herd immunity to protect them.
Vaccine-derived poliovirus
While vaccination has played an instrumental role in the reduction of polio cases worldwide, the use of attenuated virus in the oral vaccine carries with it an inherent risk. The oral vaccine is a powerful tool in fighting polio in part because of its person-to-person transmission and resulting contact immunity. However, under conditions of long-term circulation in undervaccinated populations, the virus can accumulate mutations that reverse the attenuation and result in vaccine virus strains that themselves cause polio. As a result of such circulating vaccine-derived poliovirus (cVDPV) strains, polio outbreaks have periodically recurred in regions that have long been free of the wild virus, but where vaccination rates have fallen. Oral vaccines can also give rise to persistent infection in immunodeficient individuals, with the virus eventually mutating into a more virulent immunodeficiency-associated vaccine-derived poliovirus (iVDPV). In particular, the type2 strain seems prone to reversions, so in 2016 the eradication effort abandoned the trivalent oral vaccine containing attenuated strains of all three virus types and replaced it with a bivalent oral vaccine lacking the type2 virus, while a separate monovalent type2 vaccine (mOPV2) was to be used only to target existing cVDPV2 outbreaks. A novel oral vaccine targeting type2 (nOPV2) that has been genetically stabilized to make it less prone to give rise to circulating vaccine-derived strains received full licensure in December 2023, with similar vaccines targeting types 1 and 3 undergoing clinical trials. Eradication efforts will eventually require all oral vaccination to be discontinued in favor of the use of injectable vaccines. These vaccines are more expensive and more difficult to deliver, and they lack the ability to induce contact immunity because they contain only killed virus, but they likewise are incapable of giving rise to vaccine-derived viral strains.
Surveillance
A global program of surveillance for the presence of polio and the poliovirus plays a critical role in assessment of eradication and in outbreak detection and response. Two distinct methods are used in tandem: acute flaccid paralysis (AFP) surveillance and environmental surveillance.
Monitoring for AFP aims at identifying outbreaks of polio by screening patients displaying symptoms consistent with, but not exclusive to, severe poliovirus infection. Stool samples are collected from children presenting with AFP and evaluated for the presence of poliovirus by accredited laboratories in the Global Polio Laboratory Network. Since rates of non-polio AFP are expected to be constant and large compared to the number of polio cases, the frequency of non-polio AFP reported in a population is indicative of the effectiveness of surveillance, as is the proportion of AFP patients from whom high-quality stool samples are collected and tested, with a target of at least 80%.
Environmental surveillance is used to supplement AFP surveillance. This entails the routine testing of sewage samples for the presence of virus, which not only allows the effectiveness of vaccination efforts to be evaluated in countries with active transmission, but also allows the detection of new outbreaks in countries without known transmission. In 2018, the GPEI conducted environmental surveillance in 44 countries, 24 of which are in Africa.
Obstacles
Among the greatest obstacles to global polio eradication are the lack of basic health infrastructure, which limits vaccine distribution and delivery, the crippling effects of civil war and internal strife, and the sometimes oppositional stance that marginalized communities take against what is perceived as a potentially hostile intervention by outsiders. Another challenge has been maintaining the potency of live (attenuated) vaccines in extremely hot or remote areas. The oral polio vaccine must be kept at for vaccination to be successful.
An independent evaluation of obstacles to polio eradication requested by the WHO and conducted in 2009 considered the major obstacles in detail by country. In Afghanistan and Pakistan, the researchers concluded that the most significant barrier was insecurity, but that managing human resources, political pressures, the movement of large populations between and within both countries, and inadequately resourced health facilities also posed problems, as did technical issues with the vaccine. In India, the major challenge appeared to be the high efficiency of transmission within the populations of Bihar and Uttar Pradesh states, set against the low (~80% after three doses against type1) seroconversion response seen from the vaccine. In Nigeria, the most critical barriers identified were management issues, in particular the highly variable importance ascribed to polio by different authorities at the local government level, although funding issues, community perceptions of vaccine safety, inadequate mobilisation of community groups, and issues with the cold chain also played a role. In those countries where international spread from endemic countries had resulted in the reestablishment of transmission, namely Angola, Chad, and South Sudan, the key issues identified were underdeveloped health systems and low routine vaccine coverage, although the low level of resources committed to Angola and South Sudan for the purpose of curtailing the spread of polio and climatic factors was also identified as playing a role.
Two additional challenges are found in unobserved polio transmission and in vaccine-derived poliovirus. First, most individuals infected with poliovirus are asymptomatic or exhibit minor symptoms, with fewer than 1% of infections leading to paralysis, and most infected people are unaware that they carry the disease, allowing polio to spread widely before cases are seen. In 2000, using new screening techniques for the molecular characterization of outbreak viral strains, it was discovered that some of the outbreaks were actually caused by circulating vaccine-derived poliovirus, following mutations or recombinations in the attenuated strain used for the oral polio vaccine. This discovery altered the strategy for the discontinuation of vaccination following polio eradication, necessitating an eventual switch to the more expensive and logistically more problematic inactivated polio vaccine, as continued use of the oral inactivated virus would continue to produce such revertant infection-causing strains. The risk of vaccine-derived polio will persist long after the switch to inactivated vaccine, as a small number of chronic excretors continue to produce active virus for years (or even decades) after their initial exposure to the oral vaccine.
In a 2012 interview with Pakistani newspaper Dawn, Dr. Hussain A. Gezari, the WHO's special envoy on global polio eradication and primary healthcare, gave his views on obstacles to eradication. He said that the biggest hurdle preventing Pakistan from becoming polio-free was holding district health officials properly accountable—in national eradication campaigns officials had hired their own relatives, even young children. Gezari asked, "How do you expect a seven-year-old thumb-sucking kid to implement a polio campaign of the government?" and added that, in spite of this, "the first national campaign was initiated by your government in 1994 and that year Pakistan reported 25,000 polio cases, and the number was just 198 last year, which clearly shows that the programme is working."
Opposition to vaccination efforts
One factor contributing to the continued circulation of polio immunization programs has been opposition to vaccination in some countries. In one country, Pakistan, "more than 200 polio team workers" have been killed (team members include not only vaccinators but police and security personnel) from "targeted killing and terrorism" while working on polio campaigns, (the killers motivated by the belief, spread by "radical clerics", that the vaccine is part of "a Western plot to sterilize Muslims").
In the context of the United States invasion of Afghanistan and the subsequent 2003 invasion of Iraq, rumours arose in the Muslim world that immunization campaigns were using intentionally-contaminated vaccines to sterilize local Muslim populations or to infect them with HIV. In Nigeria these rumours fit in with a longstanding suspicion of modern biomedicine, which since its introduction during the era of colonialism has been viewed as a projection of the power of western nations. Refusal of vaccination came to be viewed as resistance to western expansionism, and when the contamination rumours led the Nigerian Supreme Council for Sharia to call for a region-wide boycott of polio vaccination, polio cases in the country increased more than five-fold between 2002 and 2006, with the uncontrolled virus then spreading across Africa and globally. In Afghanistan and Pakistan, fears that the vaccine contained contraceptives were one reason given by the Taliban in issuing fatwas against polio vaccination. Religious boycotts based on contamination concerns have not been limited to the Muslim world. In 2015, after claiming that a tetanus vaccine contained a contraceptive, a group of Kenyan Catholic bishops called on their followers to boycott a planned round of polio vaccination. This did not have a major effect on vaccination rates, and dialog along with vaccine testing forestalled further boycott calls.
Other religion-inspired refusals arise from concern over whether the virus contains pig-derived products, and hence are haram (forbidden) in Islam, concern that vaccine production may have involved a prohibited taking of animal life, or a resistance to interfering with disease processes perceived to be divinely-directed. Concerns were addressed through extensive outreach, directed both toward the communities involved and respected clerical bodies, as well as promoting local ownership of the eradication campaign in each region. In early 2012, some parents refused to get their children vaccinated in Khyber Pakhtunkhwa (KPK) and in the Federally Administered Tribal Areas (FATA) but religious refusals in the rest of the country had "decreased manifold". Even with the express support of political leaders, polio workers or their accompanying security guards have been kidnapped, beaten, or assassinated.
Skepticism in the Muslim world was exacerbated when it was learned that in 2011 the Central Intelligence Agency (CIA) had conducted a fake hepatitis B immunization campaign, hoping to collect blood samples from Osama bin Laden's compound in Abbottabad in order to confirm the genetic identity of the children living there, and by implication his own presence, leading directly to his killing. In a letter written to CIA director Leon Panetta, the InterAction Alliance, a union of about 200 U.S.-based non-government organizations, deplored the actions of the CIA in using a vaccination campaign as a cover. Pakistan reported the world's highest number of polio cases (198), in 2011. and more than 60 polio vaccination workers were killed between December 2012 and April 2014. In May 2014, CIA director John Brennan prohibited his agency both from using vaccinations to cover operations and from testing samples collected by authentic vaccination campaigns.
Polio vaccination efforts have also faced resistance in another form. The priority placed on vaccination by national authorities has turned it into a bargaining chip, with communities and interest groups resisting vaccination, not due to direct opposition, but to leverage other concessions from governmental authorities. In Nigeria this has taken the form of 'block rejection' of vaccination that is only resolved when state officials agree to repair or improve schools and health-care facilities, pave roads or install electricity. There have been several instances of threatened boycotts by health workers in Pakistan over payment disputes. Some governments have been accused of withholding vaccination or the necessary accompanying infrastructure from regions where opposition to their rule is high.
Polio eradication criteria
A country is regarded as polio-free or non-endemic if no cases have been detected for a year. However, it is still possible for polio to circulate under these circumstances, as was the case for Nigeria, where a particular strain of virus resurfaced after five years in 2016. This can be due to chance, limited surveillance and under-vaccinated populations. Moreover, for WPV1—the only type of the virus which is currently circulating following the eradication of WPV2 and WPV3—only 1 in 200 infection cases exhibit symptoms of polio paralysis in non-vaccinated children, and possibly even fewer in vaccinated children.
Therefore, even a single case is indicative of an epidemic.
According to modeling, it can take four to six months of no reported cases to achieve only a 50% chance of eradication, and one to two years for e.g. 95% chance. Sensitivity of monitoring for circulation can be improved by sampling sewage. In Pakistan in the last couple of years, the number of paralysis cases has dropped relatively faster than the positive environmental samples, which has shown no progress since 2015. The presence of multiple infections with the same strain in the upstream area may not be detectable, so there are some saturation effects when monitoring the number of positive environmental samples. Furthermore, virus may shed beyond the expected duration of several weeks in certain individuals. Contagiousness can not be readily excluded. For a polio virus to be certified as eradicated worldwide, at least three years of good surveillance without cases needs to be achieved, though this period may need to be longer for a strain like WPV3, where a lower proportion of those infected demonstrate symptoms, or if virus-positive environmental samples continue to be reported. Wild poliovirus type2 was certified eradicated in 2015, the last case having been detected in 1999. Wild poliovirus type3 has not been detected since 2012, and was certified eradicated in 2019.
Timeline
1950s–1987
Following the widespread use of poliovirus vaccine in the mid-1950s, the incidence of poliomyelitis declined rapidly in many industrialized countries. Czechoslovakia became the first country in the world to scientifically demonstrate nationwide eradication of poliomyelitis in 1960. In 1962—just one year after Sabin's oral polio vaccine (OPV) was licensed in most industrialized countries—Cuba began using the oral vaccine in a series of nationwide polio campaigns. The early success of these mass vaccination campaigns suggested that polioviruses could be globally eradicated. The Pan American Health Organization (PAHO), under the leadership of Ciro de Quadros, launched an initiative to eradicate polio from the Americas in 1985.
Much of the work towards eradication was documented by Brazilian photographer Sebastião Salgado, as a UNICEF Goodwill Ambassador, in the book The End of Polio: Global Effort to End a Disease.
1988–2000
In 1988, the World Health Organization (WHO), together with Rotary International, UNICEF, and the U.S. Centers for Disease Control and Prevention (CDC) passed the Global Polio Eradication Initiative (GPEI), with the goal of eradicating polio by the year 2000. The initiative was inspired by Rotary International's 1985 pledge to raise $120million toward immunising all of the world's children against the disease. The last case of wild poliovirus poliomyelitis in the Americas was reported in Peru, August 1991.
On 20 August 1994, the Americas were certified as polio-free. This achievement was a milestone in efforts to eradicate the disease.
In 1994, the Indian Government launched the Pulse Polio Campaign to eliminate polio. The current campaign involves annual vaccination of all children under age five.
In 1995, Operation MECACAR (Mediterranean, Caucasus, Central Asian Republics, and Russia) was launched; National Immunization Days were coordinated in 19 European and Mediterranean countries. In 1998, Melik Minas of Turkey became the last case of polio reported in Europe. In 1997, Mum Chanty of Cambodia became the last person to contract polio in the Indo-West Pacific region. In 2000, the Western Pacific Region (including China) was certified polio-free.
In October 1999, the last isolation of type2 poliovirus occurred in India. This type of poliovirus was subsequently declared eradicated.
Also in October 1999, The CORE Group—with funding from the United States Agency for International Development (USAID)—launched its effort to support national eradication efforts at the grassroots level. The CORE Group commenced this initiative in Bangladesh, India, and Nepal in South Asia, and in Angola, Ethiopia, and Uganda in Africa.
2001–2005
By 2001, 575million children (almost one-tenth the world's population) had received some two billion doses of oral polio vaccine. The World Health Organization announced that Europe was polio-free on 21 June 2002, in the Copenhagen Glyptotek.
In 2002, an outbreak of polio occurred in India. The number of planned polio vaccination campaigns had recently been reduced, and populations in northern India, particularly from the Islamic background, engaged in mass resistance to immunization. At this time, the Indian state Uttar Pradesh accounted for nearly two-thirds of total worldwide cases reported. (See the 2002 Global polio incidence map.) However, by 2004, India had adopted strategies to increase ownership of polio vaccinations in marginalized populations, and the immunity gap in vulnerable groups rapidly closed.
In August 2003, rumors spread in some states in Nigeria, especially Kano, that the vaccine caused sterility in girls. This resulted in the suspension of immunization efforts in the state, causing a dramatic rise in polio rates in the already endemic country. On 30 June 2004, the WHO announced that after a 10-month ban on polio vaccinations, Kano had pledged to restart the campaign in early July. During the ban the virus spread across Nigeria and into 12 neighboring countries that had previously been polio-free. By 2006, this ban would be blamed for 1,500 children being paralyzed and had cost $450million for emergency activities. In addition to the rumors of sterility and the ban by Nigeria's Kano state, civil war and internal strife in Sudan and Côte d'Ivoire have complicated WHO's polio eradication goal. In 2004, almost two-thirds of all the polio cases in the world occurred in Nigeria (760 out of 1,170 total).
In May 2004, the first case of the polio outbreak in Sudan was detected. The reemergence of polio led to stepped up vaccination campaigns. In the city of Darfur, 78,654 children were immunized and 20,432 more in southern Sudan (Yirol and Chelkou).
In 2005, there were 1,979 cases of wild poliovirus (excluding vaccine-derived poliovirus). Most cases were located in two areas: the Indian subcontinent and Nigeria. Eradication efforts in the Indian sub-continent met with a large measure of success. Using the Pulse Polio campaign to increase polio immunization rates, India recorded just 66 cases in 2005, down from 135 cases reported in 2004, 225 in 2003, and 1,600 in 2002.
Yemen, Indonesia, and Sudan, countries that had been declared polio-free since before 2000, each reported hundreds of cases—probably imported from Nigeria. On 5 May 2005, news reports broke that a new case of polio was diagnosed in Java, Indonesia, and the virus strain was suspected to be the same as the one that has caused outbreaks in Nigeria. New public fears over vaccine safety, which were unfounded, impeded vaccination efforts in Indonesia. In summer 2005, the WHO, UNICEF and the Indonesian government made new efforts to lay the fears to rest, recruiting celebrities and religious leaders in a publicity campaign to promote vaccination.
In the United States on 29 September 2005, the Minnesota Department of Health identified the first occurrence of vaccine-derived poliovirus (VDPV) transmission in the United States since OPV was discontinued in 2000. The poliovirus type1 infection occurred in an unvaccinated, immunocompromised infant girl aged seven months (the index patient) in an Amish community whose members predominantly were not vaccinated for polio.
2006–2010
In 2006, only four countries in the world (Nigeria, India, Pakistan, and Afghanistan) were reported to have endemic polio. Cases in other countries are attributed to importation. A total of 1,997 cases worldwide were reported in 2006; of these the majority (1,869 cases) occurred in countries with endemic polio. Nigeria accounted for the majority of cases (1,122 cases) but India reported more than ten times more cases in 2006 than in 2005 (676 cases, or 30% of worldwide cases). Pakistan and Afghanistan reported 40 and 31 cases respectively in 2006. Polio re-surfaced in Bangladesh after nearly six years of absence with 18 new cases reported. "Our country is not safe, as neighbours India and Pakistan are not polio free", declared Health Minister ASM Matiur Rahman. (See: Map of reported polio cases in 2006)
In 2007, there were 1,315 cases of poliomyelitis reported worldwide. Over 60% of cases (874) occurred in India. In Nigeria, the number of polio cases fell dramatically, from 1,122 cases reported in 2006 to 285 cases in 2007. Officials credit the drop in new infections to improved political control in the southern states and resumed immunisation in the north, where Muslim clerics led a boycott of vaccination in late 2003. Local governments and clerics allowed vaccinations to resume on the condition that the vaccines be manufactured in Indonesia, a majority Muslim country, and not in the United States. Turai Yar'Adua, wife of recently elected Nigerian president Umaru Yar'Adua, made the eradication of polio one of her priorities. Attending the launch of immunization campaigns in Birnin Kebbi in July 2007, Turai Yar'Adua urged parents to vaccinate their children and stressed the safety of oral polio vaccine.
In July 2007, a student traveling from Pakistan imported the first polio case to Australia in over 20 years. Other countries with significant numbers of wild polio virus cases include the Democratic Republic of the Congo, which reported 41 cases, Chad with 22 cases, and Niger and Myanmar, each of which reported 11 cases.
In 2008, 18 countries reported cases and the total number of cases was 1,651. Of these, 1,505 occurred in the four endemic countries and 146 elsewhere. The largest numbers were in Nigeria (798 cases) and India (559 cases): these two countries combined had 82.2 percent of all cases. Outside endemic countries, Chad reported the greatest number (37 cases).
In 2009, a total of 1,604 cases were reported across 23 countries. Four endemic countries accounted for 1,256 of these, with the remaining 348 in 19 sub-Saharan countries with imported cases or re-established transmission. Once again, the largest numbers were in India (741) and Nigeria (388). All other countries had less than one hundred cases: Pakistan had 89 cases, Afghanistan 38, Chad 64, Sudan 45, Guinea 42, Angola 29, Côte d'Ivoire 26, Benin 20, Kenya 19, Burkina Faso 15, Niger 15, the Central African Republic 14, Mauritania 13, and Liberia and Sierra Leone both had 11. The following countries had single-digit numbers of cases: Uganda with 8 cases, Togo 6, Cameroon 3, the Democratic Republic of the Congo 3, Burundi 2, and Mali 2.
According to figures updated in April 2012, the WHO reported that there were 1,352 cases of wild polio across 20 countries in 2010. Reported cases of polio were down 95% in Nigeria (to a historic low of 21 cases) and 94% in India (to a historic low of 42 cases) compared to the previous year, with little change in Afghanistan (from 38 to 25 cases) and an increase in cases in Pakistan (from 89 to 144 cases). An acute outbreak in Tajikistan gave rise to 460 cases (34% of the global total), and was associated with a further 18 cases across Central Asia (Kazakhstan and Turkmenistan) and the Russian Federation, with the most recent case from this region being reported from Russia 25 September. These were the first cases in the WHO European region since 2002. The Republic of the Congo (Brazzaville) saw an outbreak with 441 cases (30% of the global total). At least 179 deaths were associated with this outbreak, which is believed to have been an importation from the ongoing type1 outbreak in Angola (33 cases in 2010) and the Democratic Republic of the Congo (100 cases).
2011–2015
In 2011, 650 WPV cases were reported across sixteen countries: the four endemic countries—Pakistan, Afghanistan, Nigeria, and India—as well as twelve others. Polio transmission recurred in Angola, Chad and the Democratic Republic of the Congo. Kenya reported its first case since 2009, while China reported 21 cases, mostly among the Uyghurs of Hotan prefecture, Xinjiang, the first non-imported cases since 1994.
The total number of wild-virus cases reported in 2012 was 223, lower than any previous year. These were limited to five countries—Nigeria, Pakistan, Afghanistan, Chad, and Niger—of which all except Nigeria had fewer cases than in 2011. Several additional countries, Chad, the Democratic Republic of the Congo, Somalia, and Yemen, saw outbreaks of circulating vaccine-derived polio. The last reported type3 case of polio worldwide had its onset 11 November 2012 in Nigeria; the last wild case outside Nigeria was in April 2012 in Pakistan, and its absence from sewage monitoring in Pakistan suggests that active transmission of this strain has ceased there. A total of 416 wild-virus cases were reported in 2013, almost double the previous year. Of these, cases in endemic countries dropped from 197 to 160, while those in non-endemic countries jumped from 5 to 256. This was due to outbreaks in Central Africa (focused in Cameroon), the Horn of Africa, and the Middle East (focused in Syria).
In April 2013, a case of wild polio in Mogadishu was reported, the first in Somalia since 2007. By October, over 170 cases had been reported in the country, with more cases in neighboring Kenya and the Somali Region of Ethiopia.
Routine sewage monitoring in 2012 had detected a WPV1 strain of Pakistani origin in Cairo, sparking a major vaccination push there. The strain spread to Israel, where there was widespread environmental detection, but like Egypt, no paralysis cases. It had more severe consequences when it spread to neighboring Syria, with the total number of cases eventually reaching 35, the first outbreak there since 1999.
In April 2013, the WHO announced a new $5.5billion, 6-year cooperative plan (called the 2013–18 Polio Eradication and Endgame Strategic Plan) to eradicate polio from its last reservoirs. The plan called for mass immunization campaigns in the three remaining endemic countries, and also dictated a switch to inactivated virus injections, to avoid the risk of the vaccine-derived outbreaks that occasionally occur from use of the live-virus oral vaccine.
In 2014, there were 359 reported cases of wild poliomyelitis, spread over twelve countries. Pakistan had the most with 306, an increase from 93 in 2013, which was blamed on Al Qaeda and Taliban militants preventing aid workers from vaccinating children in rural regions of the country. On 27 March 2014, the WHO announced the eradication of poliomyelitis in the South-East Asia Region, in which the WHO includes eleven countries: Bangladesh, Bhutan, North Korea, India, Indonesia, Maldives, Myanmar, Nepal, Sri Lanka, Thailand, and Timor-Leste. With the addition of this region, the proportion of world population living in polio-free regions reached 80%. The last case of wild polio in the South-East Asia Region was reported in India on 13 January 2011.
During 2015, 74 cases of wild poliomyelitis were reported worldwide, 54 in Pakistan and 20 in Afghanistan. There were 32 circulating vaccine-derived poliovirus (cVDPV) cases in 2015.
On 25 September 2015, the WHO declared that Nigeria was no longer considered endemic for wild polio virus, with no reported case of wild polio virus having been reported since 24 July 2014. A WPV1 strain not seen in five years resurfaced in Nigeria the following year.
The WPV2 virus was declared eradicated in September 2015 as it had not been detected in circulation since 1999, and WPV3 was declared eradicated in October 2019, having last been detected in 2012. However, both types persist as circulating vaccine-derived strains, the product of years of evolution of the attenuated "live" virus (which makes up the oral vaccine) as it transmits from the vaccinated to the unvaccinated and circulates in an under-immunized community.
2016–2020
Because cVDPV2 strains continued to arise from trivalent oral vaccine that included attenuated PV2, during 2016 this vaccine was replaced with a bivalent version lacking WPV2 as well as trivalent injected inactivated vaccine that cannot lead to cVDPV cases. This was expected to prevent new strains of cVDPV2 from arising and allow eventual cessation of WPV2 vaccination. The resulting global use of the injectable vaccine caused shortages, and led the WHO in April 2017 to recommend general use of the fIPV vaccination protocol, involving subcutaneous injection of a lower dose than used in the standard intramuscular delivery.
In 2016 there were 37 reported WPV1 cases, half as many as in 2015, with the majority of the cases in Pakistan and Afghanistan. A small number of additional cases in Nigeria, caused by WPV1, were viewed as a setback, the first being detected there in almost two years, yet the virus had been circulating undetected in regions inaccessible due to the activities of Boko Haram. There was also a cVDPV1 outbreak in Laos, while new strains of cVDPV2 arose separately in Nigeria's Borno and Sekoto states, and in the Quetta area of Pakistan, collectively causing five cases.
In 2017 there were 22 reported WPV1 polio cases with onset of paralysis in 2017, down from 37 in 2016. Eight of the cases were in Pakistan and 14 in Afghanistan, where genetic typing showed repeated introduction from Pakistan as well as local transmission. In Pakistan, transmission of several genetic lineages of WPV1 seen in 2015 had been interrupted by September 2017, though at least two genetic clusters remain. In spite of a significant drop in detected cases in Pakistan, there was an increase in the percentage of environmental samples that test positive for the polio virus, suggesting gaps in identification of infected individuals. In the third country where polio remained endemic, Nigeria, there were no cases, though as few as 7% of infants were fully vaccinated in some districts. An April 2017 spill at a vaccine production facility in the Netherlands only resulted in one asymptomatic WPV2 infection, despite release into the sewer system.
Laos was declared free of cVDPV1 in March 2017, but three distinct cVDPV2 outbreaks occurred in the Democratic Republic of the Congo, one of them of recent origin, the other two having circulated undetected for more than a year. Together they caused 20 cases by year's end. In Syria, a large outbreak began at Mayadin, Deir ez-Zor Governorate, a center of fighting in the Syrian Civil War, and also spreading to neighboring districts saw 74 confirmed cases from a viral strain that had circulated undetected for about two years. Circulation of multiple genetic lines of cVDPV2 was also detected in Banadir province, Somalia, but no infected individuals were identified.
WHO's Strategic Advisory Group of Experts on Immunization recommended that cVDPV2 suppression be prioritized over targeting WPV1, and according to protocol OPV2 is restricted to this purpose.
There were 33 reported WPV1 paralysis cases with an onset of paralysis in 2018 – 21 in Afghanistan and 12 in Pakistan. Polio in Pakistan resurged in the latter part of the year, due in part to the rates of parental refusal for vaccination increasing, with wild poliovirus detected in 20% of the year's environmental samples. In Afghanistan different strains were largely responsible for the cases in the northeast and south of the country. In Nigeria, the third country classified as having endemic transmission, security concerns continued to limit access to some areas of the country, though migration and novel vaccination approaches would reduce the number of unreached children. The nation passed two full years without a detected wild-virus case, though elimination of WPV transmission could not be confirmed.Cases caused by vaccine-derived poliovirus were reported in seven countries in 2018, with over 100 total cases, representing nine strains of cVDPV. In the Democratic Republic of the Congo, one of the outbreaks of cVDPV2 first detected in 2017 caused no additional cases, but suppression of the other two with OPV2 proved insufficient: not only did they continue, but the vaccination efforts gave rise to a novel cVDPV2 outbreak. The country experienced a total of 20 cases in 2018. Two separate cVDPV2 outbreaks in northern Nigeria produced 34 cases, as well as giving rise to 10 cases in the neighboring Niger. In Somalia, cVDPV2 continued to circulate, causing several polio cases and detected in environmental samples from as far as Nairobi, Kenya. This virus, along with newly detected cVDPV3, caused twelve total cases in the country, including one patient infected by both strains. The large number of children residing in areas inaccessible to health workers represent a particular risk for undetected cVDPV outbreaks. A cVDPV2 outbreak in Mozambique resulted in a single case. Response to the Syrian cVDPV2 outbreak continued into 2018, and virus transmission was successfully interrupted. In Papua New Guinea, a cVDPV1 strain arose, causing twenty-six polio cases across nine provinces, while a single diagnosed cVDPV1 case in neighboring Indonesia resulted from a distinct outbreak.
In 2019 there were 176 WPV1 paralysis cases detected: 29 in Afghanistan and 147 in Pakistan. In particular, in Pakistan the number of cases was surging and cross-border migration played a role in polio transmission between the two countries. While itself problematic, this also fostered a dangerous false narrative in both nations, blaming the other for the presence and spread of polio in their own country. Environmental sampling in Pakistan showed the virus' presence in eight urban areas, a setback officials attributed primarily to vaccine refusal. Opponents to vaccination in Pakistan launched a series of attacks in April that left a vaccinator and two security men dead, while false rumors and hoax videos reporting vaccine toxicity also disrupted vaccination efforts there. Wild poliovirus of Pakistani origin also spread to Iran where it was detected in several environmental samples. Overall, the eradication efforts in Pakistan and Afghanistan have been characterized as having become a "horror show", undermined by "public suspicion, political infighting, mismanagement and security problems".
In the third remaining country in which polio was classified as endemic, Nigeria, wild poliovirus has not been detected since October 2016, and levels of AFP surveillance are sufficient, even in security-compromised regions, to suggest transmission of WPV may have been interrupted. Global WPV3 eradication was certified in October 2019, the virus not having been seen since 2012.
In addition to the WPV resurgence in Pakistan and Afghanistan, 2019 saw a resurgence of cVDPV, with 378 cases. The majority of cases were caused by cVDPV2 strains that were able to arise or spread as a consequence of the withdrawal of the PV2 strain from the standard vaccination regimen. Previous cVDPV2 outbreaks in Nigeria, the Democratic Republic of Congo, and Somalia continued into 2019 and spread to neighboring countries, while several countries experienced new outbreaks. In addition to eighteen reported paralysis cases in Nigeria, the cVDPV2 outbreaks there spread to Benin, Burkina Faso, Chad, Ghana, Niger, and Togo, while the virus was also detected in environmental samples from Cameroon and Ivory Coast. Somalia's continuing outbreaks caused a half-dozen cases there and in neighboring Ethiopia, with a separate Ethiopia outbreak adding one case. The Democratic Republic of the Congo had numerous new and continuing outbreaks, producing more than 80 cases, while multiple new cVDPV2 outbreaks in Angola and the Central African Republic resulted in more than a hundred cases. Individual new outbreaks of cVDPV2 also caused more than a dozen paralysis cases each in Pakistan and the Philippines, while smaller outbreaks struck Chad, China, and Zambia. A separate cVDPV1 outbreak in the Philippines also caused cases in Malaysia, where cVDPV2 of Filipino origin was also detected in environmental samples, while additional cVDPV1 outbreaks caused six cases in Myanmar and one case in Yemen.
One hundred and forty cases of WPV1 paralysis were reported in 2020, all in Afghanistan or Pakistan.
In March 2020, the GPEI announced polio eradication resources were being redeployed against the COVID-19 pandemic, recognizing that this would adversely affect its efforts at eradicating polio. All vaccination efforts, both routine and targeted, were postponed for several months, with staff reassigned to COVID-19 control. Subsequent statistical analysis indicated that the COVID pandemic resulted in decreases of more than 30% globally in both AFP and environmental surveillance, with only 23 of 43 priority countries meeting their surveillance targets for 2020. Additional challenges were a conspiracy theory circulating on social media claiming that the polio vaccine contained coronavirus, and moves by President Donald Trump of the United States to cut funding for the World Health Organization.
Nigeria was removed from the list of countries with endemic wild poliovirus in June 2020, four years after the last recorded case in the Northern State of Borno in 2016. Two months later, the World Health Organization declared the African continent free of wild poliovirus. This certification came after extensive assessments of the certifications of National Polio Certification Commissions (NCCs) and confirmation that at least 95% of Africa's population had been immunised. WHO Director-General Tedros Adhanom called it a "great day... but not the end of polio", as there remain major continuing outbreaks of vaccine-derived poliovirus in West Africa and Ethiopia in addition to wild cases in Afghanistan and Pakistan.
Over 1000 cases caused by both continuing and novel outbreaks of cVDPV2 were reported in 2020 across twenty-four countries, with 31 additional cases of cVDPV1, and environmental detections in several additional countries with no diagnosed polio cases. While in the past cVDPV outbreaks tended to remain localized, significant international spread of these strains was observed.
2021
In 2021, there were just six confirmed cases of wild poliovirus — one in Pakistan, four in Afghanistan, and one in Malawi.
2021 saw a partial recovery from the challenges to monitoring brought on by the COVID pandemic, with 74% of high-priority countries meeting surveillance targets, an improvement of over 20% from the previous year. March 2021 also saw the first use of the modified nOPV2 vaccine in selected countries, engineered to allow vaccination against strain2 poliovirus without the frequent spawning of cVDPV2 seen with the original OPV2. Full rollout was not expected until 2023.
Despite previous resistance to eradication efforts, after their takeover of Afghanistan in 2021 the Taliban agreed to allow United Nations healthcare workers to carry out door-to-door vaccination nationwide for the first time in three years, including a commitment to allowing women to participate in the effort, and to provide safety guarantees to eradication staff. Pakistan's lone case dated from January, but the virus continued to be detected in environmental samples through December, and was present in most provinces of the country during the year. The case in Malawi, the country's first in almost three decades and the first in Africa in five years, was seen as a significant setback to the eradication effort. Based on similarity to a strain last detected in Pakistan in 2019, it is thought that WPV1 has been circulating undetected in the country for some time.
In 2021, reported cVDPV2 cases declined to 685 across 22 countries, over half occurring in Nigeria. The virus was also found in environmental samples or in those from symptom-free people in several additional African and Asian nations without reported cases. An analysis of cVDPV2 strains from 2020 and the first half of 2021 attributed them to 38 distinct emergences, representing a mix of novel strains and previously detected strains that continued to circulate, while several previously circulating strains were no longer found. 14 cases of cVDPV1 were identified in Madagascar and 3 in Yemen. No cases of cVDPV3 were observed, though it was detected in environmental samples from China, Israel, and its adjacent occupied territories.
2022
In 2022, there were 30 confirmed cases of WPV1 reported to WHO, with two and 20 cases in Pakistan and Afghanistan respectively, while eight non-endemic cases were recorded in Mozambique, the first cases in the country since 1992. The Mozambique cases derived from the strain of Pakistani origin that caused two confirmed cases in Malawi in 2021. The cases in Pakistan were the first seen in the country in 15 months, though the virus had been detected in environmental samples during the intervening period.
The residual effects of the COVID-19 pandemic continued to be a cause for concern, due to an increased risk of undetected outbreaks due to COVID's interference with routine health care, disease detection, and childhood vaccinations, as well as a concern that an increased fear of vaccines, caused at least in part by politicization of vaccination and bad governance during the pandemic, may result in a general pattern of undervaccination, including for polio. In Pakistan, a contributing factor to the resurgence of wild virus cases in the country has been threats of violence both from those with anti-vaccine sentiment and from religious extremists. A vaccination worker was assassinated in March 2022, and a vaccinator and two accompanying police officers providing security for a door-to-door vaccination campaign were murdered in June.
However, the situation had improved compared to previous years as the government and law-enforcement increased their focus. By October 2022, endemic transmission was restricted to seven districts in southern Khyber Pakhtunkhwa, and the number of circulating genetic clusters was down to one, from eleven in 2020.
The situation improved in Afghanistan as well, as between 2021 and 2022 the country became significantly more peaceful as the government consolidated their control, though with remaining pockets of violence.
Vaccine-derived cases continue to circulate, particularly in the African and Eastern Mediterranean WHO regions. Concern is focused on Ukraine, where cVDPV had been detected in fall 2021, vaccination efforts were halted due to the Russian invasion, and on poor quality surveillance extant in Southeast Africa 684 confirmed cVDPV2 cases were seen across twenty countries during 2022, in addition to 189 cases of cVDPV1 and one case of cVDPV3 in Israel. The first case since 2013 was reported in the United States, tied to cVDPV2 strains found in Israel and the United Kingdom. In Burundi and the Democratic Republic of the Congo, two outbreaks of cVDPV2 that caused a combined seven cases were identified as having a link to the nOPV2 vaccine, the first outbreaks with ties to nOPV2 after its initial deployment in 2021; according to an assessment reported by the GPEI, an estimated 30–40 additional outbreaks of cVDPV2 would have occurred from March 2021 – March 2023 without the nOPV2 rollout. Vaccine-derived viral strains were also detected in environmental samples from a number of additional countries without diagnosed cases. From February to May, traces of cVDPV2 were discovered in sewage in London, United Kingdom. This led the United Kingdom to declare a "national incident". However, authorities have said that the risk to the general public is "extremely low", and no cases have been reported.
2023
Twelve cases of WPV1 have been reported in 2023, six in Afghanistan and Pakistan each. Additionally, 187 positive environmental samples were reported in those countries.
There have been 391 confirmed cases of cVDPV2 reported to the WHO in 2023, across 22 countries, nineteen of which lie in Sub-Saharan Africa, with only a handful of cases in Indonesia, Yemen, and Israel being the exception.
cVDPV1 is now concentrated in three countries, 105 cases in the Democratic Republic of the Congo, 24 in Madagascar and four in Mozambique.
No cVDPV3 virus has been detected for two years now.
The Independent Monitoring Board of the GPEI in its September 2023 Report mentioned a continued, geographically restricted, endemic transmission in the east of Afghanistan and in the southern districts of Pakistan's Khyber Pakhtunkhwa province.
All but one wild polio generic cluster remains in Afghanistan in a much improved immunity (>90%) of the population. Levels of access in the country are the best they have been since 2018.
However, a large pool of unvaccinated children remain in the Kandahar province potentially leading to a large outbreak, if the virus reappears there.
In Pakistan, they estimate that the long-standing and intractable poliovirus circulation in most of the traditional endemic reservoirs has been eliminated. However, a positive environmental probe in Karachi, after no cases for over a year, raised concerns about the vaccination campaign quality in Pakistan.
The report found it was highly likely that the goal of interrupting wild poliovirus transmission in 2023 would be missed and it was certain that ending transmission of vaccine-derived poliovirus will not be possible this year.
2024
there have been 93 reported cases of WPV1 with 68 from Pakistan and 25 from Afghanistan. Additionally, 622 positive environmental samples have been collected in Pakistan and 106 in Afghanistan.
243 cases of cVDPV2 cases have been found across seventeen different countries, all of which are in Sub-Saharan Africa except for Indonesia in Southeast Asia, and Yemen and Palestine in the West Asia. In addition eighteen countries have had positive environmental samples of cVDPV2 but no confirmed cases: Algeria, Cote D'Ivoire, Djibouti, Egypt, Equatorial Guinea, Finland, Gambia, Germany, Ghana, Kenya, Mozambique, Poland, Senegal, Sierra Leone, Spain, Sudan, Uganda, United Kingdom and Zimbabwe. France had one positive environmental sample of cVDPV3.
Nine cVDPV1 cases have been detected in the Democratic Republic of the Congo and one in Mozambique.
After one and a half years without any cases, cVDPD3 has reappeared with three new cases in Guinea in September.
Post-Eradication Plans
WPV2 and WPV3 are certified as eradicated.
Certification of wild poliovirus eradication requires three consecutive years without case reports, in the presence of reliable disease surveillance networks. Beginning at certification of WPV eradication, the post-certification strategy will come into effect, with program priorities shifting towards outbreak preparedness and containment of existing virus material rather than circulating disease. Vaccination for WPV1 will cease one year following eradication certification, and eradication of vaccine-derived poliovirus is then targeted for 2030.
Where possible, the number of facilities conducting operations with poliovirus is to be reduced significantly; and the use of wild poliovirus is to be abandoned altogether in favour of genetically stabilized attenuated strains where possible. there are 74 designated Poliovirus Essential Facilities (PEFs) across 24 countries where work on poliovirus can be carried out. These facilities are currently involved in producing materials to assist the eradication initiative, and perform crucial research which may prevent future outbreaks. After certification, these facilities retain the equipment and materials to continue vaccine production in the event of deliberate or accidental release. Work on Poliovirus outside of the PEFs will be prohibited, and stocks in laboratories that are not designated as PEFs must either be transferred to a PEF or destroyed.
By 2022 all stocks of WPV2 had been transferred to PEFs and full containment is in effect. All other strains are in a transitionary status.
See also
Global Polio Eradication Initiative
The Final Inch, a 2009 documentary film about the eradication effort
List of diseases eliminated from the United States
Mathematical modelling of infectious disease
Polio in Pakistan
Population health
2024 Gaza Strip polio outbreak
References
Further reading
External links
Health campaigns
Infectious diseases with eradication efforts
Polio
Public health emergencies of international concern
Vaccination | Polio eradication | Biology | 12,446 |
16,796,525 | https://en.wikipedia.org/wiki/HD%2076700%20b | HD 76700 b is an exoplanet orbiting the G-type main sequence star HD 76700, approximately 198 light years away in the southern constellation Volans. The planet was discovered in 2002, and was announced in 2003.
Discovery
In 2002, a group of scientists detected planets around multiple stars, along with HD 76700. Unlike the other planets, HD 76700 b has a short and circular orbit; however, according to the newest data, the planet's orbit may be slightly eccentric.
Properties
Due to the planet's high mass, it is a gas giant similar to Saturn. HD 76700 b was detected indirectly, so properties such as its radius, inclination, and temperature is unknown. HD 76700 b has a short four day orbit around its host due to it being eight times closer than Mercury is to the Sun.
References
External links
Hot Jupiters
Exoplanets discovered in 2002
Giant planets
Volans
Exoplanets detected by radial velocity | HD 76700 b | Astronomy | 202 |
78,423,249 | https://en.wikipedia.org/wiki/75%20Seasons%3A%20The%20History%20of%20the%20NFL | 75 Seasons: The History of the NFL is a software CD-ROM from RealTime Sports and NFL Films.
Summary
The CD is narrated by Fox TV commentator Pat Summerall, the story is divided into 30 chapters each between 30 seconds and 5 minutes in length and contains hundreds of game clips and interviews. The archive can be searched alphabetically and by team and player.
Development
75 Seasons: The History of the NFL was developed by RealTime Sports, a company founded in 1993, and produced by Steve Sabol.
Reception
CNETs Matt Rosoff wrote "While the video clips of 75 Seasons might impress you, the text is mostly recycled and the interface seems thrown together without much thought. Unless you're a football fanatic, you could do better for the price." The Charlotte Observers Steven L. Kent said "Though this documentary CD ultimately might have scored stronger with a bit less video and a superior line of statistics, it does a good job of showing the unique force that defines the National Football League".
Vince Caputo, Tom Hedden, and Dave Robidoux won an Emmy for their score of the CD.
References
1995 software
Multimedia software
NFL Films
Windows software | 75 Seasons: The History of the NFL | Technology | 237 |
31,104,477 | https://en.wikipedia.org/wiki/Partial%20k-tree | In graph theory, a partial k-tree is a type of graph, defined either as a subgraph of a k-tree or as a graph with treewidth at most k. Many NP-hard combinatorial problems on graphs are solvable in polynomial time when restricted to the partial k-trees, for bounded values of k.
Graph minors
For any fixed constant k, the partial k-trees are closed under the operation of graph minors, and therefore, by the Robertson–Seymour theorem, this family can be characterized in terms of a finite set of forbidden minors. The partial 1-trees are exactly the forests, and their single forbidden minor is a triangle.
For the partial 2-trees the single forbidden minor is the complete graph on four vertices. However, the number of forbidden minors increases for larger values of k. For partial 3-trees there are four forbidden minors: the complete graph on five vertices, the octahedral graph with six vertices, the eight-vertex Wagner graph, and the pentagonal prism with ten vertices.
Dynamic programming
Many algorithmic problems that are NP-complete for arbitrary graphs may be solved efficiently for partial k-trees by dynamic programming, using the tree decompositions of these graphs.
Related families of graphs
If a family of graphs has bounded treewidth, then it is a subfamily of the partial k-trees, where k is the bound on the treewidth.
Families of graphs with this property include the cactus graphs, pseudoforests, series–parallel graphs, outerplanar graphs, Halin graphs, and Apollonian networks. For instance, the series–parallel graphs are a subfamily of the partial 2-trees, and more strongly a graph is a partial 2-tree if and only if each of its biconnected components is series–parallel.
The control-flow graphs arising in the compilation of structured programs also have bounded treewidth, which allows certain tasks such as register allocation to be performed efficiently on them.
Notes
References
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Graph families
Graph minor theory | Partial k-tree | Mathematics | 417 |
60,357,139 | https://en.wikipedia.org/wiki/CEE%207%20standard%20AC%20plugs%20and%20sockets | CEE 7 is a standard for alternating-current plugs and sockets. First published in 1951 by the former International Commission on the Rules for the Approval of Electrical Equipment (IECEE), it unified standards produced by several continental European countries. The 2nd edition was published in 1963 and last updated in March 1983. It remains available from the IEC, but they state that "this standard shall not be used alone, it is to be used in addition to IEC 60884-1".
CEE 7 standards
The International Commission on the Rules for the Approval of Electrical Equipment (IECEE) was a standards body which published Specification for plugs and socket-outlets for domestic and similar purposes as CEE Publication 7, known simply as CEE 7. It was originally published in 1951, the 2nd edition was published in May 1963 and was last updated by Modification 4 in March 1983. CEE 7 consists of general specifications, plus a number of standard sheets for specific connectors.
A number of standards based on two round pins with centres spaced at 19 mm are in use in continental Europe and elsewhere, most of which are listed in IEC/TR 60083 "Plugs and socket-outlets for domestic and similar general use standardized in member countries of IEC". There is no European Union regulation of domestic mains plugs and sockets, and the Low Voltage Directive specifically excludes domestic plugs and sockets. EU countries each have their own regulations and national standards; for example, some require child-resistant shutters, while others do not. CE marking is neither applicable nor permitted on plugs and sockets.
CEE 7/1 unearthed socket and CEE 7/2 unearthed plug
CEE 7/1 unearthed sockets are designed to accept CEE 7/2 round plugs without notches in the body and having pins.
Because they have no earth connections they have been or are being phased out in most countries. The regulations of countries using the CEE 7/3 and CEE 7/5 socket standards vary in whether CEE 7/1 sockets are still permitted in environments where the need for earthing is less critical. Sweden, for example, prohibited them from new installations in 1994. In Germany unearthed sockets are rare, whereas in the Netherlands and Sweden it is still common to find them in "dry areas" such as in bedrooms or living rooms. Some countries prohibit use of unearthed and earthed sockets in the same room, in the "insulated room" concept, so that people cannot touch an earthed object and one that has become live, at the same time.
The depth of the sockets varies between countries and age. Older sockets are so shallow that it is possible to touch the pins of a plug when the plug is inserted only deep enough to get electrical power on the pins, while newer sockets are deep enough to protect from this kind of accident. CEE 7/1 sockets accept CEE 7/4, CEE 7/6 and CEE 7/7 plugs without providing an earth connection. The earthed CEE 7/3 and CEE 7/5 sockets were specifically designed not to allow insertion of CEE 7/2 unearthed round plugs fitted to older appliances which had to be earthed via other means.
CEE 7/3 socket and CEE 7/4 plug (German "Schuko"; Type F)
The CEE 7/3 socket and CEE 7/4 plug are commonly called Schuko. The socket (which is often, in error, also referred to as CEE 7/4) has a predominantly circular recess which is deep with two symmetrical round apertures and two earthing clips on the sides of the socket positioned to ensure that the earth is always engaged before live pin contact is made. The plug pins are . The Schuko connection system is symmetrical and unpolarised in its design, allowing line and neutral to be reversed. The socket also accepts Europlugs and CEE 7/17 plugs. It is rated at 16 A. The current German standards are DIN 49441:1972-06 "Two-pole plugs with earthing-contact 10 A 250 V≅ and 10 A 250 V–, 16 A 250 V~" (which also includes CEE 7/7 plug) and DIN 49440-1:2006-01 "Two-pole socket-outlets with earthing contact, 16 A 250 V a.c."
In addition to Germany, it is used in Albania, Austria, Belarus, Bosnia and Herzegovina, Bulgaria, Chile, Croatia, Denmark, Estonia, Finland, Georgia, Greece, Hungary, Iceland, Indonesia, Iran, Italy (standard CEI 23-50), Kazakhstan, Latvia, Lithuania, Luxembourg, North Macedonia, Moldova, the Netherlands, Norway, Pakistan, Peru, Portugal, Romania, Russia, Serbia, Slovenia, South Korea, Spain, Sweden, Turkey, Ukraine, and Uruguay.
It was widely used in Ireland until 1964, a legacy of Ireland's early electricity grid which was largely built based on design work on the Shannon hydroelectric scheme by Siemens-Schuckert. The British BS1363 (localised as Irish Standard I.S.401) was adopted as the new standard plug to ease import of electrical appliances from the UK. CEE 7/1 and CEE 7/4 are still occasionally found in less used areas of some older homes, particularly in outbuildings or hot presses.
Schuko is an abbreviation for the German word Schutzkontakt, which means "Protective contact" - in this case "protective" refers to the earth.
Some countries, including South Korea, Portugal, Finland, Denmark, Norway and Sweden, require child-proof socket shutters; the German DIN 49440-1:2006-01 standard does not have this requirement.
CEE 7/5 socket and CEE 7/6 plug (French; Type E)
The CEE 7/5 socket and CEE 7/6 plug are defined in French standard NF C 61-314 "Plugs and socket-outlets for household and similar purposes" (which also includes CEE 7/7, 7/16 and 7/17 plugs) The socket has a predominantly circular recess which is deep with two symmetrical round apertures and a round earth pin projecting from the socket such that the tip is beyond the live contacts, to ensure that the earth is always engaged before live pin contact is made. The earth pin is centred between the apertures, offset by . The plug (which is often, in error, also referred to as CEE 7/5) has two round pins measuring , spaced apart and with an aperture for the socket's projecting earth pin. This standard is also used in Belgium, Denmark, Poland, Czechia, Slovakia and some other countries.
Although the plug is polarised, CEE 7 does not define the placement of the line and neutral and there is no universally-observed standard. However, the Czech and Slovak standards defined that the earth pin should be at the top, if no special reason against, and the line wire had to be on the left side when facing the socket; those requirements are abandoned now. The French convention changed circa 2002 from nothing particular, to, if the earth pin was at the top then the line hole in the socket would be on the right looking at the socket. However, the socket may not necessarily be installed with the earth pin at the top. Packaging in France of sockets is normally marked with correct connection of the cables. Polarised pre-fitted plugs on appliances are therefore connected with the brown line wire to the right pin and the blue neutral wire to the left, the earth being connected to the contact at the "top" of the plug.
CEE 7/2 and 7/4 plugs are not compatible with the CEE 7/5 socket because of the round earthing pin permanently mounted in the socket.
CEE 7/7 plug (compatible with E and F)
To bridge the differences between German and French standards, the CEE 7/7 plug was developed. It is polarised to prevent the line and neutral connections from being reversed when used with a French CEE 7/5 socket, but allows polarity reversal when inserted into a German CEE 7/3 socket. The plug is rated at 16 A.
It has earthing clips on both sides to connect with the CEE 7/3 socket and a female contact to accept the earthing pin of the CEE 7/5 socket. Currently, appliances in many countries are sold with non-rewireable CEE 7/7 plugs attached, enabling use in all countries whose socket standards are based on either CEE 7/3 or CEE 7/5.
This plug can be inserted into a Danish Type K socket, but earthing is not enabled.
CEE 7/16 plugs
The CEE 7/16 standard sheet appears in Supplement 2 (June 1962) to the 1951 edition of CEE 7. The CEE 7/16 unearthed plug is used for low power Class II applications, it has two round 4 by 19 mm (0.157 by 0.748 in) pins, rated at 2.5 A. There are two variants.
CEE 7/16 Alternative I
Alternative I is a round plug with cutouts to make it compatible with CEE 7/3 and CEE 7/5 sockets. (The similar-appearing CEE 7/17 has larger pins and a higher current rating.) This alternative is seldom used.
CEE 7/16 Alternative II "Europlug" (Type C)
Alternative II, popularly known as the Europlug, is a flat plug defined by Cenelec standard EN 50075 and national equivalents. The Europlug is not rewirable and must be supplied with a flexible cord. It is rated for voltages up to 250 V and currents up to 2.5 A. It can be inserted in either direction, so line and neutral are connected arbitrarily.
There is no socket defined by EN 50075; nor a socket specified in CEE 7 to accept only the Europlug. Instead, the Europlug was designed to be compatible with a range of sockets in common use in Europe. These sockets, including the CEE 7/1, CEE 7/3 (German/"Schuko"), CEE 7/5 (French), and most Israeli, Swiss, Danish and Italian sockets, were designed to accept pins of various diameters, mainly 4.8 mm but also 4.0 mm and 4.5 mm, and are usually fed by final circuits with either 10 A or 16 A overcurrent protection devices. To improve contact with socket parts the Europlug has slightly flexible pins which converge toward their free ends.
UK shaver sockets designed to accept BS 4573 shaver plugs also accept Europlugs for applications requiring less than 200 mA. Other than such personal hygiene applications, UK consumer protection legislation does not permit Europlugs.
The Europlug is also used in the Middle East, Africa, South America, and Asia.
CEE 7/17 unearthed plug
This is a round plug which conforms to a shape compatible with CEE 7/1, CEE 7/3, and CEE 7/5 sockets. It has two round pins measuring . It may be rated at either 10 A or 16 A, and may be used for unearthed Class II appliances (and in South Korea for all domestic non-earthed appliances). It is also defined as the Class II plug in Italian standard CEI 23-50. It can be inserted into Israeli SI 32 with some difficulty. The Soviet GOST 7396 standard includes both the CEE 7/17 and the CEE 7/16 variant II plug.
See also
Mains electricity by country
AC power plugs and sockets: British and related types
NEMA connector
References
Electrical standards | CEE 7 standard AC plugs and sockets | Physics | 2,436 |
35,098,575 | https://en.wikipedia.org/wiki/Monsky%27s%20theorem | In geometry, Monsky's theorem states that it is not possible to dissect a square into an odd number of triangles of equal area. In other words, a square does not have an odd equidissection.
The problem was posed by Fred Richman in the American Mathematical Monthly in 1965 and was proved by Paul Monsky in 1970.
Proof
Monsky's proof combines combinatorial and algebraic techniques and in outline is as follows:
Take the square to be the unit square with vertices at (0, 0), (0, 1), (1, 0) and (1, 1). If there is a dissection into n triangles of equal area, then the area of each triangle is 1/n.
Colour each point in the square with one of three colours, depending on the 2-adic valuation of its coordinates.
Show that a straight line can contain points of only two colours.
Use Sperner's lemma to show that every triangulation of the square into triangles meeting edge-to-edge must contain at least one triangle whose vertices have three different colours.
Conclude from the straight-line property that a tricolored triangle must also exist in every dissection of the square into triangles, not necessarily meeting edge-to-edge.
Use Cartesian geometry to show that the 2-adic valuation of the area of a triangle whose vertices have three different colours is greater than 1. So every dissection of the square into triangles must contain at least one triangle whose area has a 2-adic valuation greater than 1.
If n is odd, then the 2-adic valuation of 1/n is 1, so it is impossible to dissect the square into triangles all of which have area 1/n.
Optimal dissections
By Monsky's theorem, it is necessary to have triangles with different areas to dissect a square into an odd number of triangles. Lower bounds for the area differences that must occur to dissect a square into an odd numbers of triangles and the optimal dissections have been studied.
Generalizations
The theorem can be generalized to higher dimensions: an n-dimensional hypercube can only be divided into simplices of equal volume if the number of simplices is a multiple of n!.
References
Euclidean plane geometry
Theorems in discrete geometry
Geometric dissection | Monsky's theorem | Mathematics | 484 |
25,430,394 | https://en.wikipedia.org/wiki/Fina%20%28architecture%29 | In Mediterranean architecture, the fina is a physical space used in urban design, corresponding to the approximately 1-meter-wide public space alongside buildings. It is used to describe the placement of design items within traditional architectural elements. It also mandates public rules of behaviour for the neighbours concerning the usage and maintenance of finas in their buildings. For instance, a person has the right to use the part of the fina immediately in front of his home for the loading or unloading of his vehicle but he has no right to block it.
Fina is identified as a convention in ancient Levant architecture that denotes a zone along the street wall of a building where balconies, downspouts, and other protruding features were allowed as long as they did not impede the passage of public transport and other users of the street. In Islamic architecture, fina or Al-Fina, which emerged in old Islamic cities that were organized by Islamic law, refers to a patio – an open-sky courtyard of a central building. It serves to illuminate and ventilate rooms and spaces inside buildings. This particular architectural concept is still used in urban spaces in the Middle East such as Egypt as a form of environmental organizer. This in-between space also influences the urban fabric and character of the city.
Fina has two types of uses: temporary and permanent. Trees, flower pots, window gratings and other decorations constitute the temporary uses of fina. Its permanent use are represented by built-in structures such as stairs, benches, and water-related infrastructure, among others. These also include the sabat, which is a structure built between the opposite buildings on both sides of a narrow street. It is constituted by rooms bridging the street. It provides a passageway to respect the right of way, and the supporting pillars of the resulting arch must be within the fina.
References
Further reading
Arabic-Islamic cities: building and planning principles. BS Hakim - 1986 - Kegan Paul Intl
Mediterranean urban and building codes: origins, content, impact, and lessons, Urban Design International
Learning from Traditional Mediterranean Codes by Besim Hakim. The Town Paper -Council report III/IV - April 2003
Generative processes for revitalising historic towns or heritage districts by Besim Hakim. INTBAU - International Network for Traditional Building, Architecture & Urbanism.
Urban design | Fina (architecture) | Engineering | 481 |
39,383,381 | https://en.wikipedia.org/wiki/2-hydroxy-dATP%20diphosphatase | 2-hydroxy-dATP diphosphatase (, also known as oxidized purine nucleoside triphosphatase, or (2'-deoxy) ribonucleoside 5'-triphosphate pyrophosphohydrolase, or Nudix hydrolase 1 (NUDT1), or MutT homolog 1 (MTH1), or 7,8-dihydro-8-oxoguanine triphosphatase) is an enzyme that in humans is encoded by the NUDT1 gene. During DNA repair, the enzyme hydrolyses oxidized purines and prevents their addition onto the DNA chain. As such it has important role in aging and cancer development.
Function
This enzyme catalyses the following chemical reaction
2-hydroxy-dATP + H2O 2-hydroxy-dAMP + diphosphate
The enzyme hydrolyses oxidized purine nucleoside triphosphates. The enzyme is used in DNA repair, where it hydrolysis the oxidized purines and prevents their addition onto the DNA chain.
Misincorporation of oxidized nucleoside triphosphates into DNA and/or RNA during replication and transcription can cause mutations that may result in carcinogenesis or neurodegeneration. First isolated from Escherichia coli because of its ability to prevent occurrence of 8-oxoguanine in DNA, the protein encoded by this gene is an enzyme that hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP, 8-oxo-dATP, 2-oxo-dATP, 2-hydroxy-dATP, and 2-hydroxy rATP, to monophosphates, thereby preventing misincorporation.
MutT enzymes in non-human organisms often have substrate specificity for certain types of oxidized nucleotides, such as that of E. coli, which is specific to 8-oxoguanine nucleotides. Human MTH1, however, has substrate specificity for a much broader range of oxidatively damaged nucleotides. The mechanism of hMTH1's broad specificity for these oxidized nucleotides is derived from their recognition in the enzyme's substrate binding pocket due to an exchange of protonation state between two nearby aspartate residues.
The encoded protein is localized mainly in the cytoplasm, with some in the mitochondria, suggesting that it is involved in the sanitization of nucleotide pools both for nuclear and mitochondrial genomes. In plants, MTH1 has also been shown to enhance resistance to heat- and paraquat-induced oxidative stress, resulting in fewer dead cells and less accumulation of hydrogen peroxide.
Several alternatively spliced transcript variants, some of which encode distinct isoforms, have been identified. Additional variants have been observed, but their full-length natures have not been determined. A single-nucleotide polymorphism that results in the production of an additional, longer isoform has been described.
Research
Aging
A mouse model has been studied that over-expresses hMTH1-Tg (NUDT1). The hMTH1-Tg mice express high levels of the hMTH1 hydrolase that degrades 8-oxodGTP and 8-oxoGTP and therefore excludes 8-oxoguanine from DNA and RNA. The steady state levels of 8-oxoguanine in DNA of several organs including the brain are significantly reduced in hMTH1-Tg over-expressing mice. Conversely, MTH1-null mice exhibit a significantly higher level of 8-oxo-dGTP accumulation than that of the wild type. Over-expression of hMTH1 prevents the age-dependent accumulation of DNA 8-oxoguanine that occurs in wild-type mice. The lower levels of oxidized guanines are associated with greater longevity. The hMTH1-Tg animals have a significantly longer lifespan than their wild-type littermates. These findings provide a link between ageing and oxidative DNA damage (see DNA damage theory of aging).
Cancer
Studies have suggested that this enzyme plays a role in both preventing the formation of cancer cells and the proliferation of cancer cells. This makes it a topic of interest in cancer research, both as a potential method for healthy cells to prevent cancer and a weakness to target within existing cancer cells.
Eliminating the MTH1 gene in mice results in over three times more mice developing tumors compared to a control group. The enzyme's much-studied ability to sanitize a cell's nucleotide pool prevents it from developing mutations, including cancerous ones. Specifically, another study found that MTH1 inhibition in cancer cells leads to incorporation of 8-oxo-dGTP and other oxidatively damaged nucleotides into the cell's DNA, damaging it and causing cell death. However, cancer cells have also been shown to benefit from use of MTH1. Cells from malignant breast tumors exhibit extreme MTH1 expression compared to other human cells. Because a cancer cell divides much more rapidly than a normal human cell, it is far more in need of an enzyme like MTH1 that prevents fatal mutations during replication. This property of cancer cells could allow for monitoring of cancer treatment efficacy by measuring MTH1 expression. Development of suitable probes for this purpose is currently underway.
Disagreement exists concerning MTH1's functionality relative to prevention of DNA damage and cancer. Subsequent studies have had difficulty reproducing previously reported cytotoxic or antiproliferation effects of MTH1 inhibition on cancer cells, even calling into question whether MTH1 truly does serve to remove oxidatively damaged nucleotides from a cell's nucleotide pool. One study of newly discovered MTH1 inhibitors suggests that these anticancer properties exhibited by the older MTH1 inhibitors may be due to off-target cytotoxic effects. After revisiting the experiment, the original authors of this claim found that while the original MTH1 inhibitors in question lead to damaged nucleotides being incorporated into DNA, they demonstrate the others that do not induce toxicity fail to introduce the DNA lesion. Research into this topic is ongoing.
As a drug target
MTH1 is a potential drug target to treat cancer, however there are conflicting results regarding the cytotoxicity of MTH1 inhibitors toward cancer cells.
Karonudib, an MTH1 inhibitor, is currently being evaluated a phase I clinical trial for safety and tolerability.
A potent and selective MTH1 inhibitor AZ13792138 has been developed by AstraZeneca has been made available as a chemical probe to academic researchers. However AstraZeneca has found that neither AZ13792138 nor genetic knockdown of MTH1 displays any significant cytotoxicity to cancer cells.
See also
NUDT15
8-oxo-dGTP diphosphatase
References
Further reading
External links
Nudix hydrolases
EC 3.6.1
DNA repair | 2-hydroxy-dATP diphosphatase | Biology | 1,494 |
16,184,041 | https://en.wikipedia.org/wiki/Howard%20Wilson%20Emmons | Howard Wilson Emmons (1912–1998) was an American professor in the department of Mechanical Engineering at Harvard University. During his career he conducted original research on fluid mechanics, combustion and fire safety. Today he is most widely known for his pioneering work in the field of fire safety engineering. He has been called "the father of modern fire science" for his contribution to the understanding of flame propagation and fire dynamics. He also helped design the first supersonic wind tunnel, identified a signature of the transition to turbulence in boundary layer flows (now known as "Emmons spots"), and was the first to observe compressor stall in a gas turbine compressor (still a major item of research today). He initiated studies on diffusion flames inside a boundary layer, and Emmons problem is named after him. He was eventually awarded the Timoshenko Medal by the American Society of Mechanical Engineers and the 1968 Sir Alfred Egerton Gold Medal from The Combustion Institute.
Upon Professor Emmons' death, Professor Patrick Pagni wrote, "It is not possible to properly summarize the magnitude of Professor Emmons' unique contributions to the establishment of fire safety science as a discipline, other than to call him "Mr. Fire Research".
He continues to be remembered through the Emmons Lecture at International Symposium of The International Association for Fire Safety Science and the Howard W. Emmons Distinguished Scholar Endowment at Worcester Polytechnic Institute.
Biography
Born in Morristown, New Jersey on August 30, 1912.
Bachelor of Engineering in mechanical engineering from Stevens Institute of Technology in 1933.
Master of Engineering in mechanical engineering from Stevens Institute of Technology in 1935.
Doctor of Science in mechanical engineering for Harvard University in 1938.
Advisors were John Finnie Downie Smith and Charles Harold Berry.
Worked briefly for Westinghouse and the University of Pennsylvania.
Professor at Harvard from 1940 onwards.
Notable student was Richard Ernest Kronauer, who later became an expert on human circadian rhythms.
US National Academy of Engineering member in 1965.
US National Academy of Sciences member in 1966.
Wife Dorothy
Children Beverly, Scott, and Keith
Died November 20, 1998
Awards and honors
American Physical Society Fellow, elected 1946
Honorary ScD from Stevens Institute of Technology, 1963
US National Academy of Engineering member, 1965
US National Academy of Sciences member, 1966
Egerton Gold Medal from the Combustion Institute, 1968
100th Anniversary Medal from Stevens Institute of Technology, 1970
Timoshenko Medal from ASME, 1971
Stevens Honor Award Medallion from Stevens Institute of Technology, 1970
Named Fire Protection Man of the Year by the Society of Fire Protection Engineers, 1982
Office of Naval Research Prize from the American Physical Society, 1982
Fluid Dynamics Prize (APS), 1982
Arthur B. Guise Medal by the Society of Fire Protection Engineers, 1986
Selected publications
Sole Author
The Drop Condensation of Vapors
Harvard University Thesis (S.D.), 1938.
Gas dynamics tables for air
Dover: New York, NY, 1947.
Fundamentals of Gas Dynamics
Princeton University Press: Princeton NJ, 1958.
Fluid mechanics and combustion
Proceedings of the 13th International Symposium on Combustion, p. 1-18
Pittsburgh, Pa., Combustion Institute, 1971.
“The Further History of Fire Science” Combustion Science and Technology, 40,
1984 (reprinted in Fire Technology, 21(3), 1985 )
Joint
Thermodynamic properties of helium to 50.000K
by Wilbert James Lick, Howard Wilson Emmons
Harvard University Press: Cambridge, MA, 1962.
Transport properties of helium from 200 to 50.000K
by Wilbert James Lick, Howard Wilson Emmons
Harvard University Press: Cambridge, MA, 1965.
The fire whirl
by Howard W. Emmons and Shuh-Jing Ying
Proceedings of the 11th International Symposium on Combustion, p. 475-486
Pittsburgh, Pa., Combustion Institute, 1967.
See also
Howard W Emmons, Memorial Tributes: National Academy of Engineering, Volume 10 (2002) National Academy of Engineering
TV show where Howard Emmons speaks of the 1980 MGM Las Vegas fire and of the fire code Harvard
The Web of Mechanicians
Howard W. Emmons Papers at WPI
Notes
References
Howard W. Emmons, Authority on Fire Safety, Dies at 86, Harvard University Gazette (Dec 3 1998).
Kronauer, Land, Stone, and Abernathy, Howard Wilson Emmons, Faculty of Arts and Sciences - Memorial Minute, Harvard University Gazette (March 1, 2007).
Bryner, S.L., ed. "Symposium in Memory of Professor Howard Emmons", Fifteenth Meeting of the UJNR Panel on Fire Safety, Volume 2, March 2000.
Land, R.I. and Trefethen, L.M. "A Tribute To Howard Wilson Emmons, 1912–1998", Journal of Fluids Engineering 121(2), p. 234-235 (June 1999).
Beyler, Craig. "Guest Editorial: Professor Howard Emmons 1912-1998", Fire Technology 35(1), p. 1 (Feb 1999).
External links
1912 births
1998 deaths
People from Morristown, New Jersey
Harvard John A. Paulson School of Engineering and Applied Sciences alumni
Stevens Institute of Technology alumni
University of Pennsylvania faculty
20th-century American physicists
Members of the United States National Academy of Sciences
Harvard University faculty
Thermodynamicists
Members of the United States National Academy of Engineering
Fellows of the American Physical Society | Howard Wilson Emmons | Physics,Chemistry | 1,082 |
5,720,090 | https://en.wikipedia.org/wiki/Benzylidene%20compounds | Benzylidene compounds are, formally speaking, derivatives of benzylidene, although few are prepared from the carbene. Benzylidene acetal is a protecting group in synthetic organic chemistry of the form PhCH(OR)2. For example, 4,6-O-benzylidene-glucopyranose is a glucose derivative. Benzylidene is an archaic term for compounds of the type PhCHX2 and PhCH= substituents (Ph = C6H5). For example, dibenzylideneacetone is (PhCH=CH)2CO. Benzal chloride, PhCHCl2, is alternatively named benzylidene chloride.
Benzylidene is the molecule C6H5CH. It is a triplet carbene (CAS RN 3101-08-4). It is generated by irradiation of phenyldiazomethane.
See also
Aurone
3,5-Difluoro-4-hydroxybenzylidene imidazolinone
References
External links
Aromatic compounds | Benzylidene compounds | Chemistry | 229 |
45,580,657 | https://en.wikipedia.org/wiki/Cystoderma%20chocoanum | Cystoderma chocoanum is a species of mushroom in the family Agaricaceae. Described as new to science in 1993, it was originally found in the tropical lowlands of Colombia, growing on decaying wood. The specific epithet chocoanum refers to the Department of Chocó in Colombia. It has also been reported from Brazil.
References
External links
Agaricaceae
Fungi of Brazil
Fungi of Colombia
Fungi described in 1993
Fungus species | Cystoderma chocoanum | Biology | 90 |
11,355,230 | https://en.wikipedia.org/wiki/DTUsat | DTUsat (COSPAR 2003-031C) was a CubeSat built by students from the Technical University of Denmark. It was launched on 30 June 2003 from the Plesetsk Cosmodrome on a Rockot launcher. Contact with the satellite was never established.
See also
List of CubeSats
External links
Official homepage
Student satellites
CubeSats
Spacecraft launched by Rokot rockets | DTUsat | Astronomy | 80 |
49,752,515 | https://en.wikipedia.org/wiki/Scanning%20electron%20cryomicroscopy | Scanning electron cryomicroscopy (CryoSEM) is a form of electron microscopy where a hydrated but cryogenically fixed sample is imaged on a scanning electron microscope's cold stage in a cryogenic chamber. The cooling is usually achieved with liquid nitrogen. CryoSEM of biological samples with a high moisture content can be done faster with fewer sample preparation steps than conventional SEM. In addition, the dehydration processes needed to prepare a biological sample for a conventional SEM chamber create numerous distortions in the tissue leading to structural artifacts during imaging.
See also
Electron microscopy
Electron cryomicroscopy
Transmission electron cryomicroscopy
References
Electron microscopy
Scientific techniques | Scanning electron cryomicroscopy | Chemistry | 139 |
57,301,571 | https://en.wikipedia.org/wiki/V392%20Persei | V392 Persei, also known as Nova Persei 2018, is a bright nova in the constellation Perseus discovered on April 29, 2018. It was previously known as a dwarf nova.
Dwarf nova
A U Geminorum-type variable star or dwarf nova is a type of cataclysmic variable star consisting of a close binary star system in which one of the components is a white dwarf that accretes matter from a cool main sequence or subgiant companion. V392 Persei was discovered in 1970 and received its variable star designation a year later. It is normally visual magnitude 17.4 and experiences outbursts of 2-3 magnitudes. Its spectrum in the quiescent state has been studied and only the cool star is detected. The spectrum shows emission lines of hydrogen-alpha (Hα) and both neutral and ionised helium. The brightest recorded observations is at magnitude 5.6.
Nova eruption
On April 29, 2018 it was discovered by Yuji Nakamura to be extremely bright, and it was spectroscopically confirmed as a nova outburst with magnitude 6.2 on April 30. The spectrum includes broad Hα and FeII emission lines with P Cygni profiles. The absorption core is blueshifted by a velocity of 2,680 km/s, which would be the expansion velocity from the nova explosion.
Observations with Fermi-LAT on April 30 show a strong gamma-ray source at the coordinates of the nova. Photometry of the nova from Konkoly Observatory on May 1, 2018 give apparent magnitudes of 7.38 in the V band and 8.22 in the B band, suggesting it is already declining.
System
V392 Persei is the southern of a pair of stars separated by 8.5".
The symbiotic pair are unresolved, with an orbital period of only 3.21997 days, and the nature of the cool component is unclear. The spectral energy distribution is inconsistent with a bright giant star but it could be less luminous red clump giant or subgiant. If the cool component was a main sequence red dwarf as expected for a dwarf nova, then the system would need to be closer than the suggested by its Gaia parallax.
Gallery
See also
List of novae in the Milky Way galaxy
References
External links
Dwarf Nova V392 Persei Goes Big — It’s Now Binocular Bright
How A Dwarf Nova Hit The Big Time May 2, 2018
Nova in Perseus
V392 Per in outburst, showing spectra of the nova in outburst and previously
20180430
Perseus (constellation)
Persei, V392
Dwarf novae
J04432138+4721257
Double stars | V392 Persei | Astronomy | 556 |
14,664,896 | https://en.wikipedia.org/wiki/Daily%20urban%20system | The daily urban system (DUS) refers to the area around a city, in which daily commuting occurs. It is a means for defining an urban region by including the areas from which individuals commute. Daily Urban System is a concept first introduced by the American geographer Berry, and then introduced into Europe by the British geographer Hall.
Definition
Daily urban system (DUS) mainly focuses on urban cities, where majority of the commuting flow take place. However, some case studies do look at the outskirts and suburban areas around specific urban cities that are being studied. The daily commuting includes both work and leisure, contributing to high density in the daily urban system. That results in slowing the speed of transportation. The speed of transportation is about 16 km/h at the central parts of urban cities, but speed may vary from place to place.
Urban sprawl is the possible outcome of an expansion of the daily urban system. Therefore, it includes multiple local governments, economies, and demographics. The researchers that study daily urban system (DUS) are basically focusing on the transportation planning. Some are interested in micro-analysis of an urban area per se, some carry out macro analysis of a region that is made up of several urban cities.
The difference between an agglomeration of an urban area and the daily urban system is that, an agglomeration is a multivariate means of combining townships, counties, and other defined areas. It looks at shared economic relationships and other factors. A daily urban system, on the other hand, only show how far away people who commute into a city are living. It shows how much sprawl has occurred, or how people are living far away from where they commute to everyday due to differences in conditions between the regions.
Cases
Olomouc, Czechia
A study in Olomouc research on the traveling distance among locations such as schools, hospitals, retail stores, and culture and sports centers of the region, and the towns in the hinterland of Olomouc too. The findings were different for the region and towns. The towns had shown reduction in traveling distance for commercial services, such as pharmacies and banking services. There were groceries and retail shops moving to large commercial centers too, cutting down traveling distance, which people were able to shop at the malls without having to travel much. However, the study found little changes region wise, especially in health care and education sectors. Commute for schools and health care institutions had remained stable.
Randstad area, Netherlands
Researchers looked into the daily urban systems within Randstad to determine if the megalopolis is considered a network city. Commute within Randstad remained loose despite the rising proportions of the population commuting to work over a decade (1992 to 2002). Many residents from the suburban areas were still commuting to work at the urban areas - large daily urban system - every day after ten years due to low job growth. Randstad was not considered as a network city because of its negative commuting balance, where large proportion of residents had to commute to large daily urban system for work.
Paris, France
Paris' central urban population is 2,125,246. Its agglomerated population is 9,644,507. That's a big difference. Roughly 7 million people live outside of Paris proper, but are easily within the greater Parisian area. Paris's daily urban system has a population of 11,174,743. That's 1.5 million people living outside of what can (at the most generous) be called Paris, and yet are commuting there every day. 10% of the city lives far enough away that they cannot really say they 'live outside of Paris,' but commute there daily.
See also
15 minute city
Commuter town
Commuting zone
Exurb
Isochrone map
Transit desert
Travel to work area
Urban Employment Area
References
Human geography
Urban planning
Urbanization
Economic geography
Transportation planning | Daily urban system | Engineering,Environmental_science | 808 |
71,910,590 | https://en.wikipedia.org/wiki/List%20of%20Art%20Deco%20architecture%20in%20California | This is a list of buildings that are examples of the Art Deco architectural style in California, United States.
Auburn
Auburn City Hall and Fire House, Auburn, 1937
Auburn Placer Performing Arts Center, Auburn, 1930
Earl Crabbe Gymnasium, Auburn, 1937
Bakersfield
Bakersfield City School District (former Washington Middle School Auditorium), Bakersfield, 1940s
Central Fire Station, Bakersfield, 1939
Fox Theater, Bakersfield, 1930
Kern County Hall of Records, Bakersfield, 1939
Standard School Auditorium, Bakersfield, 1937
Berkeley
82 Shattuck Square, Berkeley, 1926
Berkeley Community Theatre, Berkeley, 1950
Berkeley High School, Berkeley, 1935–1939
Berkeley Iceland, Berkeley, 1940
Berkeley Public Library, Berkeley
Edwards Stadium, Berkeley, 1932
Pacific Film Archive, Berkeley, 1939
Beverly Hills
Advance Company Building, Beverly Hills, 1929
Fine Arts Theatre (former Wilshire Regina Theatre), Beverly Hills, 1937
Payne Building, Beverly Hills, 1926 and 1936
Saban Theatre, Beverly Hills, 1930
Sterling Plaza, Beverly Hills, 1929
Culver City
Allied Model Trains, Culver City, 1946
Beacon Laundry, Culver City, 1931
Citizens Publishing Company Building, Culver City, 1929
Helms Bakery Building, Culver City
U.S. Post Office, Culver Boulevard, 1940
Fresno
Azteca Theater, Fresno, 1948
Crest Theater, Fresno, 1949
Fresno County Hall of Records, Fresno, 1937
Fresno Memorial Auditorium, Fresno, 1936
Fresno Unified School District Administration Building, Fresno, 1936
Gottschalks Department Store, Fresno, 1914
Ivory Tower, Mayfair Shopping Center, Fresno, 1945
L. C. Wesley Super Garage, Fresno, 1931
Scottish Rite Masonic Temple, Fresno, 1937
Tower Theatre, Fresno, 1939
United States Post Office, Fresno, 1939
Glendale
Aeroscopic Environmental Inc. Building, Glendale, 1935
Alex Theatre, Glendale, 1925
Galilee Mission Center, Glendale, 1930s
Glendale City Hall, Glendale, 1942
Grand Central Airport, Glendale, 1923
Incarnation Catholic Church, Glendale, 1952
Incarnation Church School, Glendale, 1937
North Glendale Methodist Church, Glendale, 1941
Long Beach
1862 Atlantic Avenue, Long Beach, 1930
Acres of Books, Long Beach, 1924
Atlantic Studio, Long Beach, 1933
Barker Brothers Building, Long Beach, 1929
Buffums' Autoport, Long Beach, 1941
Charles A. Lindberg Middle School, Long Beach, 1933
Dr. Rowan Building (former Bank of Italy), Long Beach, 1930
Jefferson Junior High School, Long Beach, 1936
Lafayette Hotel, Long Beach, 1929
Long Beach Airport, Long Beach, 1923
Long Beach Main Post Office, Long Beach, 1934
Long Beach Polytechnic High School Auditorium, Long Beach, 1935
Long Beach Professional Building, Long Beach, 1929
Long Beach Skating House (now Palace Lofts), Long Beach, 1929
Marvin Apartments, Long Beach, 1930
Merrill Building, Long Beach, 1921
Municipal Utilities Building, Long Beach, 1932
Owl Drug Store (now Julian Medical Building), Long Beach, 1934
, Long Beach, 1936
Robert Louis Stevenson School, Long Beach, 1936
Siam Market (former Repp Mott Auction House), Long Beach, 1930
Soft Water Laundry (now Long Beach Rescue Mission), Long Beach, 1920s
Thrifty Drug/Famous Department Store, Long Beach, 1929
Tichenor Orthopedic Clinic for Children, Long Beach, 1938
United States Post Office Long Beach Main, Long Beach, 1934
Walkers Department Store, Long Beach, 1929
Wiese & Wiese Building, Long Beach, 1929
Los Angeles
535 South Gramercy Place, Los Angeles, 1931
3919 West 8th Street, Los Angeles, 1940
4845 Fountain Avenue, Hollywood, Los Angeles, 1930
Abraham Lincoln High School, Lincoln Heights, Los Angeles, 1938
Academy Museum of Motion Pictures, Los Angeles, 1940
American Legion Post 377, Tujunga, Los Angeles, 1928
Angelus Temple, Echo Park, Los Angeles, 1923
Biegler Hall, University of Southern California, Los Angeles, 1940
Big Town Market, Los Angeles, 1940s
Black Cat Tavern, Los Angeles, 1939
Bob's Automatic Transmissions, Los Angeles, 1936
Bullocks Wilshire, Los Angeles, 1929
California Bank, Los Angeles, 1930
Carpenter Community Charter School, Studio City, Los Angeles, 1924
Cedars of Lebanon Hospital (now Scientology's Big Blue Building), Hollywood, Los Angeles, 1930
Central Library Goodhue, Los Angeles, 1926
Coca-Cola Building, Los Angeles, 1939
Comedy Union Building, Los Angeles, 1930s
Commercial Laundry Building, Hollywood, Los Angeles, 1928
Crossroads of the World, Los Angeles, 1936
Distribution Station No. 28 Department of Water and Power, West Los Angeles, Los Angeles, 1946
Dominguez-Wilshire Building, Los Angeles, 1931
E. Clem Wilson Building, Los Angeles, 1929
E. F. Smith Market, Los Angeles, 1933
Eastern Columbia Building, Los Angeles, 1930
El Rey Theatre, Los Angeles, 1936
Ennis House, Los Feliz, Los Angeles, 1924
Federal Reserve Bank of San Francisco, Los Angeles Branch, Los Angeles, 1929
Film Exchange Building, Los Angeles, 1937
Firestone Tire Company Building, Los Angeles, 1937
Fox Bruin Theater, Los Angeles, 1937
Garfield Building, Los Angeles, 1929
Golden State Mutual Life Insurance Building, South Los Angeles, Los Angeles, 1949
Good Ship Grace, Los Angeles, 1941
Grauman's Egyptian Theatre, Hollywood, Los Angeles, 1922
Green Dog & Cat Hospital, Los Angeles, 1934
Griffith Observatory, Los Angeles, 1935
Hattern's Shopping Center (now Scientology Community Center), Los Angeles, 1931
Hemphill Diesel Engineering School, Los Angeles, 1932–1936
Hoffman Candy Company, Los Angeles, 1929
Hollyhock House, East Hollywood, Los Angeles, 1921
Hollywood American Legion Post 43 Clubhouse, Los Angeles, 1929
Hollywood & Western Building, Hollywood, Los Angeles, 1928
Hollywood Bowl, Hollywood Hills, Los Angeles, 1929
Hollywood Citizen-News Building, Hollywood, Los Angeles, 1931
Hollywood High School, Hollywood, Los Angeles, 1938
Hollywood Palladium, Hollywood, Los Angeles 1940
Hollywood Reporter Building, Los Angeles, 1924 and 1947
Howard Hughes Headquarters Building, Hollywood, Los Angeles, 1931
International College of Beauty Arts & Sciences (former Aero Industries Technical Institute), Los Angeles
James Oviatt Building, Los Angeles, 1927
Judge Redwine Building, Hollywood, Los Angeles
Kenneth Hahn Hall of Administration, Los Angeles, 1960
Los Angeles Central Library, Los Angeles, 1926
Los Angeles City Hall, Los Angeles, 1928
Los Angeles County – USC Medical Center, Los Angeles, 1933
Los Angeles Fire Department Engine Co. No. 1, Los Angeles, 1940
Los Angeles Memorial Coliseum, Exposition Park, Los Angeles, 1923
Los Angeles Times Building, Los Angeles, 1935
Los Feliz Manor Apartments, Los Angeles, 1929
Los Angeles Center for Enriched Studies, Faircrest Heights, Los Angeles, 1937
Majestic Crest Theatre, Los Angeles
Manual Arts High School, Los Angeles, 1910 and 1933
The Mauretania, Los Angeles, 1934
Mayan Theater, Los Angeles, 1927
Milk, Los Angeles, 1931
Montecito Apartments, Hollywood, Los Angeles, 1930
Moxley Veterinary, Los Angeles, 1930
Municipal Water & Power Building, Los Angeles, 1937
North Hollywood Masonic Temple, Hollywood, Los Angeles, 1949
Pacific Exchange, Los Angeles, 1930
Pan-Pacific Auditorium, Los Angeles, 1935
Pantages Theatre, Hollywood, Los Angeles, 1930
Park Plaza Hotel, Los Angeles, 1924
Pellissier Building and Wiltern Theatre, Los Angeles, 1931
Pickford Center for Motion Picture Study, Los Angeles, 1948
Producers Film Center (former Good Humor Building), Los Angeles, 1930
Punch TV Studios, Los Angeles, 1935
Ravenswood Apartments, Hollywood, Los Angeles, 1912
Roxie Theatre, Downtown Los Angeles, 1931
Roxy Theatre, Hollywood, Los Angeles, 1973
Rush Hour Jewelry, Los Angeles
Samuel-Novarro House, Los Feliz, Los Angeles, 1927
San Pedro Ballet School, San Pedro, Los Angeles 1935
San Pedro High School, San Pedro, Los Angeles, 1936
San Pedro Municipal Ferry Building, San Pedro, Los Angeles, 1941
Scully Building, Los Angeles, 1930
Sears, Roebuck & Company Mail Order Building, Boyle Heights, Los Angeles, 1927
Security First National Bank, Los Angeles, 1929
Selig Retail Store, Los Angeles, 1931
Selma Las Palmas Courtyard Apartments, Hollywood, Los Angeles, 1939
Shane Building (former Directors Guild of America), Los Angeles, 1930 Skinner House, Los Angeles, 1937
Sontag Drug Store (now Wilshire Beauty), Los Angeles, 1935
Southern California Edison Company Building, Los Angeles
Southern California Gas Company Complex, Downtown Los Angeles, 1925
Southwestern Law School, Los Angeles, 1911
Spring Street Courthouse, Los Angeles, 1940
Storer House, Hollywood Hills, Los Angeles, 1924
Sun Realty Company Building (now Los Angeles Jewelry Center), Los Angeles, 1930
Sunset Tower, Los Angeles, 1931
Thomas Jefferson High School, South Los Angeles, Los Angeles, 1936
Title Guarantee and Trust Company Building, Los Angeles, 1930
Union Station, Los Angeles, 1939
United States Post Office Hollywood Main, Hollywood, Los Angeles, 1937
United States Post Office, San Pedro, Los Angeles, 1935
Van Nuys City Hall, Van Nuys, Los Angeles, 1932
Venice High School, Los Angeles, 1911
Venice Police Station, Los Angeles, 1930
Victor M. Carter House, Los Angeles, 1935
Village Green, Baldwin Hills, Los Angeles, 1930s–1942
Vine Street Elementary School, Hollywood, 1934
Vision Theater, Leimert Park, South Los Angeles, Los Angeles, 1931
Wallace Beery Duplex, Los Angeles, 1936
Warner Grand Theatre, San Pedro, Los Angeles, 1931
Wilshire Ward Chapel, Los Angeles, 1929
Wiltern Theatre, Los Angeles, 1931
Merced
Blooming Affair Global & Gifts, Merced,
The Mainzer, Merced, 1920s and 1931
Merced Theatre, Merced, 1931
Napa
Bank of Napa (now Wells Fargo), Napa, 1934
Food City Building (now Family Drug), Napa, 1952
Oberon Building, Napa, 1893, 1934
United States Post Office, Napa, 1933
Oakland
10th Street Market, Oakland, 1917 and 1926
347 14th Street, Oakland, 1920s
Alameda County Courthouse, Oakland, 1939
Breuner's Building, Oakland, 1931
Fox Oakland Theatre, Oakland, 1928
Hill Castle Apartment Building, Oakland, 1930
I. Magnin Building, Oakland, 1930
Mary A. Bowles Building, Oakland, 1931
Oakland Floral Depot (now Uptown nightclub), Oakland, 1923
Paramount Theatre, Oakland, 1931
Posey and Webster Street Tubes, Oakland, 1928
Sears Roebuck & Company, Oakland, 1929
Palo Alto
Acme Glass Company, Palo Alto, 1938
Hoover Pavilion, Palo Alto, 1931
Stanford Theatre, Palo Alto, 1920s
Pasadena
Armory Gallery, Pasadena, 1932
Bryan's Cleaners, Pasadena, 1938
Bullock's Pasadena, Pasadena, 1944
Court at 744–756½ South Marengo Avenue, Pasadena, 1931
Glenarm Power Plant, Pasadena, 1927
Grover Cleveland Elementary School, Pasadena, 1934
Pasadena Winter Garden, Pasadena, 1940
Rose City Dental Arts, Pasadena, 1932
Royal Laundry Complex, Pasadena, 1927
Warner Building (now Linden Optometry), Pasadena, 1927
Sacramento
California Transportation Commission, Sacramento, 1939
Capitol Plaza (former I.O.O.F. Building), Sacramento, 1870 and 1936
Chando's Cantina, Sacramento, 1948
Colonial Theatre, Sacramento, 1940
Crest Theatre, Sacramento, 1946
Forum Building, Sacramento, 1911
Frank Fat's Restaurant, Sacramento, 1939
Grant Union High School Auditorium, Sacramento
Iceland Skating Rink, Sacramento, 1940
Lee House, Sacramento, 1941
Metro Garage (former Greyhound Station), Sacramento
Odd Cookie (former People's Acceptance Building), Sacramento
S. H. Kress and Co. Building, Sacramento, 1931
Sacramento City College Gymnasium and Auditorium, Sacramento, 1937
Theodore Judah School, Sacramento, 1937
Tower Bridge, Sacramento, 1935
Tower Theatre, Sacramento, 1938
San Bernardino
Helms Bakery Building, San Bernardino, 1950s
Landeros Furniture, San Bernardino, 1927
San Bernardino Tattoo, San Bernardino,
San Diego
3090 Polk Avenue, San Diego, 1930
3489 Noell Street, San Diego, 1940s
3701 6th Avenue, San Diego, 1930s
4304 Park Boulevard (former Frank the Train Man), San Diego, 1943
Architectural Salvage, San Diego, 1930s
Dalton Building, Gaslamp Quarter, San Diego, 1911 and 1930
Euclid Tower (now Tower Bar), San Diego, 1932
Fire Station No. 4, San Diego, 1937
Ford Building, Balboa Park, San Diego
McClintock Storage Warehouse, San Diego, 1925
Municipal Gymnasium, Balboa Park, San Diego, 1935
Piggly Wiggly (now Krisp Beverages and Natural Foods), San Diego, 1940
Samuel I. Fox Building, Gaslamp Quarter, San Diego, 1929
San Diego Athletic Club, San Diego, 1928
San Diego Central Post Office, San Diego, 1937
San Diego County Administration Center, San Diego, 1938
San Diego Firehouse Museum, San Diego, 1920s
Silverado Ballroom, San Diego, 1931
Silver Gate Three Stars Masonic Lodge No 296, San Diego, 1931
Sixth Church of Christ, scientist, San Diego, 1940s or 1950s
San Francisco
140 New Montgomery, South of Market, San Francisco, 1925
450 Sutter Street, San Francisco, 1929
Administration Building, Treasure Island, San Francisco, 1938
Balboa Theatre, San Francisco, 1926
Bank of Italy (now Bank of America), San Francisco
Beach Chalet, San Francisco, 1925
Bently Nob Hill, San Francisco, 1924
Bridge Cafe, San Francisco, 1938
Round House Café, San Francisco, 1938
Castro Theatre interior, San Francisco, 1922
Central Tower, San Francisco, 1898, 1938
Circus Center (former Polytechnic High School Gymnasiums), San Francisco, 1929
Coit Tower, San Francisco, 1933
Discount Glass Building, San Francisco, 1936
Doelger Building, Inner Sunset District, San Francisco, 1932
El Rey Theatre, 1931
Eng-Skll Company, San Francisco, 1930
Federal Reserve Bank of San Francisco, San Francisco, 1929
Francis Scott Key Elementary School, San Francisco, 1938
George Washington High School, San Francisco, 1934–1936
Golden Gate Bridge, San Francisco, 1937
Hall of Transportation Building 2, Treasure Island, San Francisco, 1938
Horseshoe Tavern, San Francisco, 1934
James Lick Middle School, San Francisco, 1932
Lakeside Medical Center, San Francisco
Malloch Building, Telegraph Hill, San Francisco, 1937
Maritime Museum, San Francisco Maritime National Historical Park, San Francisco, 1936
McAllister Tower Apartments, San Francisco, 1930
NBC Studio Building, San Francisco, 1941
New Mission Theater, San Francisco, 1916
Ocean Park Motel, San Francisco, 1937
Omar Khayyam's Restaurant, 200 Powell Street, San Francisco
One Montgomery Tower, San Francisco, 1982
Palace of Fine and Decorative Arts Building 3, Treasure Island, San Francisco, 1938
Presidio Theatre, Marina District, San Francisco, 1937
Rincon Center, San Francisco, 1940
Roxie Theater, Mission District, San Francisco, 1933
Sailor's Union of the Pacific, San Francisco, 1950
San Francisco Galvanizing Works, San Francisco
San Francisco Mint, San Francisco, 1937
San Francisco VA Medical Center, San Francisco, 1934
Sears Roebuck & Co., San Francisco, 1926
Shell Building, San Francisco, 1929
Speaker Towers, Aquatic Park Historic District, San Francisco, 1939
Star of the Sea School, San Francisco, 1940s
Stock Exchange Tower, 155 Sansome Street, San Francisco, 1930
Transbay Terminal, San Francisco, 1939
United States Appraisers and Stores and Immigration Station, Financial District, San Francisco, 1944
Verdi Club, San Francisco, 1935
Santa Ana
Empire Market Building, Downtown Santa Ana, Santa Ana, 1933
Horton Furniture Building, Downtown Santa Ana, Santa Ana, 1929
Old Santa Ana City Hall, Downtown Santa Ana, Santa Ana, 1935
Santa Ana Performing Arts Event Center, Downtown Santa Ana, Santa Ana, 1923
Santa Monica
Charmont Apartments, Santa Monica, 1928
Georgian Hotel, Santa Monica, 1931
Santa Monica City Hall, Santa Monica, 1939
Sears, Roebuck & Company, Santa Monica, 1947
Shangri-La Apartments, Santa Monica, 1940
United States Post Office, Santa Monica, 1937
Vogue Apartments, Santa Monica, 1937
Voss Apartments, Santa Monica, 1937
Wilshire Theatre
Stockton
Fox California Theater, Stockton, 1930
Connell Motor Truck Co., Stockton,
United States Post Office, Stockton, 1933
Visalia
Department of Public Social Services (former Tulare County Courthouse), Visalia, 1935
Masonic Temple, Visalia, 1935
United States Post Office-Visalia Town Center Station, Visalia, 1933
Whittier
Cool-A-Coo Building, Whittier, 1930
Lou Henry Hoover School, Whittier, 193
National Trust and Savings, Whittier, 1935
St. Mary of the Assumption Catholic Church, Whittier, 1930
United States Post Office, Whittier, 1935
Whittier-Union High School, Whittier, 1940
Other cities
6990 Palm Avenue, Highland Historic District, Highland, 1936
Administrative Building, Sacramento McClellan Airport (former Sacramento Air Depot), Sacramento County, 1936
Aimee's Castle, Lake Elsinore,
Alameda Theatre, Alameda, 1932
Albany Cinema, Albany,
Alex Theatre, Glendale, 1925
Amador County Courthouse, Jackson Downtown Historic District, Jackson, 1940
Americanization School/Crown Heights Resource Center, Oceanside, 1931
Analy High School, Sebastopol, 1935
Angels 6 Theatre, Angels Camp, 1936
Arcadia News Journal Building, Arcadia, 1932
Arcata Theatre Lounge, Arcata, 1937
Arena Theater, Point Arena, 1928
Avalon Theatre, Catalina Casino, Santa Catalina Island, 1929
Avenal Theater, Avenal, 1935
Aztec Hotel, Monrovia, 1924
Bank of America, Chico, 1931
Bank of America, Los Gatos, 1931
Beekay Theatre, Tehachapi, 1932
Bella Terra, Huntington Beach, 1965
Bernardi's Cleaners (now Red Onion restaurant), Alameda, 1946
Beverly Fabrics, Salinas, 1920s
Bishop Twin Theatre, Bishop, 1929
Blue Cross Veterinary Hospital, Signal Hill, 1927
Boathouse, Alhambra
Bowling Alley, La Crescenta-Montrose
Broadway Twin Theatre, Yreka, 1930
Bubbles Balboa Club, Newport Beach, 1950s
Bun-N-Burger, San Gabriel, 1941
Burbank City Hall, Burbank, 1943
Butte County Hospital, Oroville, 1945
California Theater, Dunsmuir, 1926
Cascade Theatre, Redding, 1934
Catalina Casino, Avalon, 1929
Christian Science Reading Room, Santa Barbara, 1950
Christopher B. Smith Rafael Film Center, San Rafael
City Hall, Hayward, 1930
City Hall, Livermore, 1875 and 1937
City Hall, Maywood, 1938
City Hall, Nevada City, 1937
Claypool & Co. (now Palo Verde College), Needles, 1930
Colin P. Kelly Elementary School (Streamline Moderne), Compton, 1933
Cloverdale Creamery, Fremont, 1927
Court House, Nevada City Downtown Historic District, Nevada City, 1937
Cow Palace, Daly City, 1941
Daily Republic Building, Fairfield
De Anza Hotel, San Jose, 1931
De Anza Theatre (S. Charles Lee, Streamline Moderne), 1937–1939
Dr. George Hein's Residence and Dental Practice (now J&M Hobby House), San Carlos, 1936
Doheny Courtyard, West Hollywood, 1930s
Eagles Building, Redondo Beach, 1949
El Primero Hotel, Chula Vista, 1930
El Segundo Elementary School, El Segundo, 1936
Esslinger Building, San Juan Capistrano, 1939
Esparto High School Auditorium, Esparto
Eugene C. Jones Veterinary Office, West Hollywood, 1938
Eureka Theater, Eureka, 1939
Fine Arts Theatre (former Wilshire Regina Theatre), Beverly Hills, 1937
First Baptist Church, Ventura, 1932
First National Trust and Savings Bank, La Mesa, 1942
Fox Theatre Inglewood, Inglewood, 1949
Fremont Theater, San Luis Obispo, 1942
Gamble House, Fullerton, 1940
Golden Gate Theater, East Los Angeles, Los Angeles County, 1927
Green's Cleaners, South Gate, 1940
Hart Theatre, Ferndale, 1920
Hollywood Park Racetrack building, Streamline Moderne
Inglewood Memorial Park Buildings, Inglewood, 1933
KIGS AM Radio Station, Hanford, 1947
KPH Radio Station, Inverness, 1930
King City High School Auditorium, King City, 1939
Lane-Wells Company Building, Huntington Park, 1939
Lark Theater, Larkspur, 1936
Leuzinger High School, Lawndale, 1931
Lido Restaurant, South Gate, 1941
Loma Linda Foods Building (now Heritage Foods), Riverside, 1937
Los Baños del Mar, Los Alamos, 1939
Marconi–RCA Transmitting Station, Bolinas, 1931
Martinez Downtown Post Office, Martinez, 1939
Martinez Library, Martinez, 1941
Metro Diner, Escondido, 1947
Mitchell Real Estate Building, Grass Valley, 2008–2012
Modoc Union High School, Alturas, 1939
Monroe Elementary School, Monrovia, 1930s
Monterey County Court House, Monterey, 1937
Mt. Whitney Hotel, Lindsay, 1929
Napa Auto Parts, Mojave, 1940s
New Weed Palace Theater, Weed, 1933
Niles Theater, Alturas, 1937
North School, Hermosa Beach, 1934
Oceanside City Hall and Fire Station, Oceanside, 1929
Orinda Theatre, Orinda
Petersen's Service Station, Ferndale Main Street Historic District, Ferndale, 1930
Pier Avenue School, Hermosa Beach, 1939
Point Hueneme Light, Santa Barbara Channel, 1941
Pomona Fox Theater, Pomona, late 1920s
Progress Building, Pomona, 1932
Puente de Vida Church, Santa Paula, 1950
Redding Fire House, Redding, 1939
Richmond Shipyard Number Three Warehouse, Richmond, 1941
Ritz Building, Eureka
Rosenberg's Department Store, Santa Rosa, 1937
Safeway (now Bonanza Tortilleria), Modesto, 1937
Salinas Californian Building, Salinas, 1949
San Gabriel Union Church and School, San Gabriel, 1936
San Luis Obispo County Courthouse, San Luis Obispo, 1940
Santa Anita Park, Arcadia, 1934
Santa Cruz Civic Auditorium, Santa Cruz, 1939
Sebastiani Theatre, Sonoma, 1934
Senator Theater, Chico, 1928
Shell Gas Station, La Grange, 1925
Ship of the Desert, Palm Springs, 1936
Social and Public Art Resource Center, Venice, 1929
South Pasadena High School, South Pasadena, 1906
State Theatre, Red Bluff, 1946s
Sterling Cleaners, Burlingame, 1926
Sutter Creek Theatre, Sutter Creek, 1919
Taft Union High School, Taft,
Tate's Tea Room/Carlos Club, San Carlos, 1947
Thurlow Medical Building, Santa Rosa, 1940
Torrance High School Auditorium, Torrance, 1924
Torrance Public Library, Torrance, 1936
Town & Country Center, Palm Springs, 1948
Tulare Union High School Auditorium and Administration Building, Tulare, 1937
Ukiah Main Post Office, Ukiah, 1938
United States Post Office, Gardena Boulevard, Gardena
United States Post Office, Hillcrest Avenue, Inglewood
United States Post Office, Lancaster, 1940
United States Post Office, Porterville, 1937
United States Post Office-Santa Barbara Main, Santa Barbara, 1937
Urho Saari Swim Stadium, El Segundo, 1940
Val Vita Food Products, Fullerton, 1939
Veterans Memorial Building, Corning, 1930s
W. W. Henry Company Building, Huntington Park, 1939
Wardrobe Cleaners (now Catalina Coffee Company), Redondo Beach, 1950
Washington Firehouse (now Burgers and Brew), West Sacramento
Whittier Union High School, Whittier, 1940
See also
List of Art Deco architecture
List of Art Deco architecture in the United States
Art Deco in the United States#California (PWA Moderne listing)
References
"Art Deco & Streamline Moderne Buildings." Roadside Architecture.com. Retrieved 2019-01-03.
"Art Deco Society of Los Angeles". Archived from the original on 2015-05-17.
Cinema Treasures. Retrieved 2022-09-06
"Court House Lover". Flickr. Retrieved 2022-09-06
"New Deal Map". The Living New Deal. Retrieved 2020-12-25.
"Points of Interest Map". Art Deco Society of California. Archived from the original on 2019-01-03. Retrieved 2019-01-03.
"SAH Archipedia". Society of Architectural Historians. Retrieved 2021-11-21.
External links
Art Deco
Lists of buildings and structures in California | List of Art Deco architecture in California | Engineering | 4,935 |
5,791,186 | https://en.wikipedia.org/wiki/Bone%20density | Bone density, or bone mineral density, is the amount of bone mineral in bone tissue. The concept is of mass of mineral per volume of bone (relating to density in the physics sense), although clinically it is measured by proxy according to optical density per square centimetre of bone surface upon imaging. Bone density measurement is used in clinical medicine as an indirect indicator of osteoporosis and fracture risk. It is measured by a procedure called densitometry, often performed in the radiology or nuclear medicine departments of hospitals or clinics. The measurement is painless and non-invasive and involves low radiation exposure. Measurements are most commonly made over the lumbar spine and over the upper part of the hip. The forearm may be scanned if the hip and lumbar spine are not accessible.
There is a statistical association between poor bone density and higher probability of fracture. Fractures of the legs and pelvis due to falls are a significant public health problem, especially in elderly women, leading to substantial medical costs, inability to live independently and even risk of death. Bone density measurements are used to screen people for osteoporosis risk and to identify those who might benefit from measures to improve bone strength.
Testing
A bone density test may detect osteoporosis or osteopenia. The usual response to either of these indications is consultation with a physician. Bone density tests are not recommended for people without risk factors for weak bones, which is more likely to result in unnecessary treatment rather than discovery of a weakness.
Indications for testing
The risk factors for low bone density and primary considerations for a bone density test include:
females age 65 or older.
males age 70 or older.
people over age 50 with:
previous bone fracture from minor trauma.
rheumatoid arthritis.
low body weight.
a parent with a hip fracture.
individuals with vertebral abnormalities.
individuals receiving, or planning to receive, long-term glucocorticoid (steroid) therapy.
individuals with primary hyperparathyroidism.
individuals being monitored to assess the response or efficacy of an approved osteoporosis drug therapy.
when androgen deprivation therapy is being planned for prostate cancer.
individuals with a history of eating disorders.
Other considerations that are related to risk of low bone density and the need for a test include smoking habits, drinking habits, the long-term use of corticosteroid drugs, and a vitamin D deficiency.
Test result terms
Results of the test are reported in three forms:
Measured areal density in g cm−2.
Z-score: the number of standard deviations above or below the mean for the patient's age, sex and ethnicity.
T-score: the number of standard deviations above or below the mean for a healthy 30-year-old adult of the same sex and ethnicity as the patient.
Types of tests
While there are many types of bone mineral density tests, all are non-invasive. The tests differ according to which bones are measured to determine the test result.
These tests include:
Dual-energy X-ray absorptiometry (DXA or DEXA)
Trabecular bone score
Dual X-ray Absorptiometry and Laser (DXL)
Quantitative computed tomography (QCT)
Quantitative ultrasound (QUS)
Single photon absorptiometry (SPA)
Dual photon absorptiometry (DPA)
Digital X-ray radiogrammetry (DXR)
Single energy X-ray absorptiometry (SEXA)
DXA is the most commonly used testing method . The DXA test works by measuring a specific bone or bones, usually the spine, hip, and wrist. The density of these bones is then compared with an average index based on age, sex, and size. The resulting comparison is used to determine the risk for fractures and the stage of osteoporosis (if any) in an individual.
Quantitative ultrasound (QUS) has been described as a more cost-effective approach for measuring bone density, as compared to DXA.
Average bone mineral density = BMC / W [g/cm2]
BMC = bone mineral content = g/cm
W = width at the scanned line
Interpretation
Results are generally scored by two measures, the T-score and the Z-score. Scores indicate the amount one's bone mineral density varies from the mean. Negative scores indicate lower bone density, and positive scores indicate higher.
Less than 0.5% of patients who underwent DXA-scanning were found to have a T- or Z-score of more than +4.0, often the cause of an unusually high bone mass (HBM) and associated with mild skeletal dysplasia and the inability to float in water.
T-score
The T-score is the relevant measure when screening for osteoporosis. It is the bone mineral density at the site when compared to the "young normal reference mean". It is a comparison of a patient's bone mineral density to that of a healthy 30-year-old. The US standard is to use data for a 30-year-old of the same sex and ethnicity, but the WHO recommends using data for a 30-year-old white female for everyone. Values for 30-year-olds are used in post-menopausal women and men over age 50 because they better predict risk of future fracture. The criteria of the World Health Organization are:
Normal is a T-score of −1.0 or higher
Osteopenia is defined as between −1.0 and −2.5
Osteoporosis is defined as −2.5 or lower, meaning a bone density that is two and a half standard deviations below the mean of a 30-year-old man/woman.
Z-score
The Z-score for bone density is the comparison to the "age-matched normal" and is usually used in cases of severe osteoporosis. This is the standard score or number of standard deviations a patient's bone mineral density differs from the average for their age, sex, and ethnicity. This value is used in premenopausal women, men under the age of 50, and in children and adolescents. It is most useful when the score is less than 2 standard deviations below this normal. In this setting, it is helpful to scrutinize for coexisting illnesses or treatments that may contribute to osteoporosis such as glucocorticoid therapy, hyperparathyroidism, or alcoholism.
Prevention
To prevent low bone density it is recommended to have sufficient calcium and vitamin D. Sufficient calcium is defined as 1,000 mg per day, increasing to 1,200 mg for women above 50 and men above 70. Sufficient vitamin D is defined as 600 IUs per day for adults 19 to 70, increasing to 800 IUs per day for those over 71. Exercise, especially weight-bearing and resistance exercises are most effective for building bone. Weight-bearing exercise includes walking, jogging, dancing, and hiking. Resistance exercise is often accomplished through lifting weights. Other therapies, such as estrogens (e.g., estradiol, conjugated estrogens), selective estrogen receptor modulators (e.g., raloxifene, bazedoxifene), and bisphosphonates (e.g., alendronic acid, risedronic acid), can also be used to improve or maintain bone density. Tobacco use and excessive alcohol consumption have detrimental effects on bone density. Excessive alcohol consumption is defined as more than one standard-sized alcoholic beverage per day for women, and drinking two or more alcoholic beverages per day for men.
Genetics
Bone mineral density is highly variable between individuals. While there are many environmental factors that affect bone mineral density, genetic factors play the largest role. Bone mineral density variation has been estimated to have 0.6–0.8 heritability factor, meaning that 60–80% of its variation is inherited from parents. Because of the heritability of bone mineral density, family history of fractures is considered as a risk factor for osteoporosis. Bone mineral density is polygenic and many of the genetic mechanisms remain poorly understood.
Genetic diseases associated with bone mineral density
There are several rare genetic diseases that have been associated with pathologic changes in bone mineral density. The table summarizes these diseases:
References
Mass density
Bones | Bone density | Physics | 1,736 |
49,438,920 | https://en.wikipedia.org/wiki/List%20of%20gravitational%20wave%20observations | This page contains a list of observed/candidate gravitational wave events.
Origin and nomenclature
Direct observation of gravitational waves, which commenced with the detection of an event by LIGO in 2015, plays a key role in gravitational wave astronomy. LIGO has been involved in all subsequent detections to date, with Virgo joining in August 2017.
Joint observation runs of LIGO and VIRGO, designated "O1, O2, etc." span many months, with months of maintenance and upgrades in-between designed to increase the instruments sensitivity and range. Within these run periods, the instruments are capable of detecting gravitational waves.
The first run, O1, ran from September 12, 2015, to January 19, 2016, and succeeded in its first gravitational wave detection. O2 ran for a greater duration, from November 30, 2016, to August 25, 2017. O3 began on April 1, 2019, which was briefly suspended on September 30, 2019, for maintenance and upgrades, thus O3a. O3b marks resuming of the run and began on November 1, 2019. Due to the COVID-19 pandemic O3 was forced to end prematurely. O4 began on May 24, 2023; initially planned for March, the project needed more time to stabilize the instruments.
The O4 observing run has been extended from one year to 18 months, following plans to make further upgrades for the O5 run. Updated observing plans are published on the official website, containing the latest information on these runs. There is a two month commissioning break planned from January to March 2024, after which observations will resume for the remainder of O4.
Gravitational wave events are named starting with the prefix GW, while observations that trigger an event alert but have not (yet) been confirmed are named starting with the prefix S. Six digits then indicate the date of the event, with the two first digits representing the year, the two middle digits the month and two final digits the day of observation. This is similar to the systematic naming for other kinds of astronomical event observations, such as those of gamma-ray bursts.
Probable detections that are not confidently identified as gravitational wave events are designated LVT ("LIGO-Virgo trigger"). Known gravitational wave events come from the merger of two black holes (BH), two neutron stars (NS), or a black hole and a neutron star (BHNS). Some objects are in the mass gap between the largest predicted neutron star masses (Tolman–Oppenheimer–Volkoff limit) and the smallest known black holes.
List of gravitational wave events
Candidate events and marginal detections
There is possible detection of nanohertz waves by observation of the timing of pulsars, but they have not been confirmed at the 5 sigma level of confidence, .
Marginal detections from O1 and O2
In addition to well-constrained detections listed above, a number of low-significance detections of possible signals were made by LIGO and Virgo. Their characteristics are listed below, only including detections with a <50% chance of being noise:
Observation candidates from O3/2019
From observation run O3/2019 on, observations are published as Open Public Alerts to facilitate multi-messenger observations of events. Candidate event records can be directly accessed at the Gravitational-Wave Candidate Event Database (GraceDB). On 1 April 2019, the start of the third observation run was announced with a circular published in the public alerts tracker. The first O3/2019 binary black hole detection alert was broadcast on 8 April 2019. A significant percentage of O3 candidate events detected by LIGO are accompanied by corresponding triggers at Virgo.
False alarm rates are mixed, with more than half of events assigned false alarm rates greater than 1 per 20 years, contingent on presence of glitches around signal, foreground electromagnetic instability, seismic activity, and operational status of any one of the three LIGO-Virgo instruments. For instance, events S190421ar and S190425z weren't detected by Virgo and LIGO's Hanford site, respectively.
The LIGO/Virgo collaboration took a short break from observing during the month of October 2019 to improve performance and prepare for future plans, with no signals detected in that month as a result.
The Kamioka Gravitational Wave Detector (KAGRA) in Japan became operational on 25 February 2020, likely improving the detection and localization of future gravitational wave signals. However, KAGRA does not report their signals in real-time on GraceDB as LIGO and Virgo do, so the results of their observation run will likely not be published until the end of O3.
The LIGO-Virgo collaboration ended the O3 run early on March 27, 2020, due to health concerns from the COVID-19 pandemic.
Observation candidates from O4/2023
On 15 June 2022, LIGO announced to start the O4 observing run in March 2023. As the date got closer, engineering challenges delayed the observing run to May 2023. An engineering run to assess the sensitivity of LIGO, Virgo, and KAGRA began in April, with the Hanford detector's first operations beginning on April 29, and the Livingston and Virgo detectors' first operations beginning on May 5.
On March 7, 2023, a gamma-ray burst compatible with a neutron star merger was detected by the Fermi telescope and named GRB 230307A. The burst, identified as being from a host galaxy approximately 296 Mpc away, would likely have only been marginally detected at best by LIGO if it had been operating at the time, as the detectors would only later achieve a sensitivity of 160 Mpc for neutron star mergers by O4's beginning, 3 months later.
Near the end of the engineering run on 15 May 2023, LIGO announced that O4 would be beginning on 24 May 2023, running for 20 months with up to 2 months of maintenance. The LIGO detectors initially failed to achieve the hoped for 160-190 Mpc sensitivity for neutron star mergers, but did achieve an improved 130-150 Mpc sensitivity over O3's 100-140 Mpc, later improving to nearly 160 Mpc for both detectors by late 2023. Virgo was found to have both a damaged mirror and other new, unknown noise sources, limiting its sensitivity to just 31-35 Mpc (similar to its performance during O2 in 2017, and lower than O3's 40-50 Mpc.) As a result, Virgo spent most of 2023 in commissioning, with a deadline of March 2024 to improve its sensitivity before joining O4. KAGRA achieved its planned 1 Mpc sensitivity before returning to commissioning in July, with plans to rejoin at an improved 10 Mpc sensitivity by early 2024. However, the 7.5 2024 Noto earthquake occurred on 1 January 2024 only from KAGRA, damaging the detector's sensitive instruments and delaying its development by at least several months.
On 18 May 2023, near the end of the engineering run and shortly before O4 proper, the first candidate gravitational wave event was detected. Four more were detected before the official beginning of the run. In October, LIGO announced a planned pause between January and March 2024, for a mid-run commissioning break intended to reduce noise and improve the uptime of the detectors.
The O4b run began in April 2024 with the addition of the Virgo detector at a sensitivity of 55 Mpc. The Livingston detector achieved an increased sensitivity of 170-175 Mpc, while the Hanford detector maintained its pre-break sensitivity of 155-160 Mpc. Due to a variety of factors including delays in technologies required for O5, the decision was made in June 2024 to extend O4 by several months to June 2025, with O5 expected to begin in late 2027 or early 2028.
See also
GRB 150101B, a weak gamma-ray burst trigger observed prior to aLIGO O1 (beginning September 12, 2015), with claimed similarities to model-supported possible neutron star merger GW170817/GRB 170817A/AT2017gfo.
Notes
References
External links
List
Gravitational waves
Gravitational waves
Observational astronomy
Binary systems | List of gravitational wave observations | Physics,Astronomy | 1,698 |
71,638,617 | https://en.wikipedia.org/wiki/Machilus%20kurzii | Machilus kurzii is a species of flowering plant in the laurel family (Lauraceae). It is native to mainland tropical Asia.
Description
Machilus kurzii is a small to medium-sized tree, growing 8 to 15 meters tall.
Range and habitat
Machilus kurzii ranges from the Eastern Himalayas in the west through northern Indochina and southern China (Yunnan province).
It is native to montane evergreen broadleaf forests and secondary growth, sometimes over limestone, between 800 and 2,000 meters elevation.
Human use
In Laos, the bark of Machilus kurzii, known as bong tree or yangbong, is harvested for gum and aromatic oils which are used to make incense sticks. Bong tree bark from wild trees has been over-harvested from wild trees, and wild tree populations have declined significantly. Since the early 2000s Laotians have been establishing hillside commercial bong tree plantations.
References
kurzii
Flora of East Himalaya
Flora of Indo-China
Flora of Yunnan
Incense material | Machilus kurzii | Physics | 209 |
25,121,200 | https://en.wikipedia.org/wiki/Aculab | Aculab is a privately held, UK-based limited company that was founded in 1978. With headquarters and R&D facilities located in Milton Keynes, UK, and its branch office is in Norwood, Massachusetts, USA.
Ladan Baghai-Ravary is the company CEO.
It is a designer, developer and manufacturer that specialises in providing API-driven, enabling technology sub-systems for telecommunications related OEM products such as are used in fixed line PSTN, wireless and VoIP networks. Its products are sold worldwide, primarily through direct sales and also via the reseller channel.
Company history
In 1978, Aculab was a design consultancy involved in the music industry. Soon after the first microprocessors were introduced, it began to design and manufacture intelligent interfaces and controllers for computer peripherals. In 1988, Aculab turned to building analogue speech processing sub-systems for a number of clients, such as British Telecom.
In 1991, Aculab began to ship the first E1 interface cards for the UK and German markets. These PC Industry Standard Architecture (ISA) form factor cards enabled PC-based speech processing products to be connected to digital public switched telephone network (PSTN) networks. The expansion of its product capabilities to include the physical interfaces and telecommunications protocols (Integrated Services Digital Network (ISDN), channel-associated signaling (CAS) and Signaling System 7 (SS7)) needed to reach a broader, worldwide market, helped to establish Aculab as one of the pioneers of the computer telephony industry.
Later, in 1997, Aculab introduced its own ISA speech processing board, the first of its portfolio of digital signal processor (DSP)-based voice boards. And it was in 1998 that Aculab introduced a Peripheral Component Interconnect (PCI) product, the first combined trunk card and voice board – Prosody PCI. It was novel for its time, delivering up to 240 speech channels and 4 E1/T1 trunk interfaces on a single card at a time when the standard was 24 to 30 channels. A Prosody cPCI (CompactPCI) version followed in 2000.
During 1993, Aculab introduced Groomer, a protocol converter that enabled interconnection between disparate telephone networks running incompatible protocols. In 2002, the product was relaunched as GroomerII, a signalling and media gateway that can be used for connection between equipment and applications deployed in time-division multiplexing (TDM) and Internet Protocol (IP) networks. Aculab's GIII gateway is the third generation evolution in the product line.
In 2003, Aculab introduced Prosody S, a host media processing (HMP) alternative to traditional, DSP-based voice boards, for IP-based OEM products. In 2011, four years after launching the ApplianX range of gateways, it launched Aculab Cloud - a cloud-based telephony API service platform.
In December 2024, the firm was acquired by the British subsidiary controlled by Enghouse Systems.
Currently offered products
Prosody X
Prosody X is a DSP-based media processing platform that offers the low level functions and technologies typically used by OEMs in their end-user product lines. Those enabling technologies include VoIP, SIP, fax, conferencing, and narrow and wideband (HD Voice) codecs. Aculab's DSP-based platforms include integral E1/T1 interfaces with CAS, ISDN and SS7 signalling and protocol support. Aculab's SS7 stack includes ISUP, signalling monitoring, and non-call related TCAP signalling functionality.
Prosody S
Prosody S is an IP-based, software-only host media processing (HMP) product that offers a range of media server technologies, including VoIP, SIP, T.38 fax, conferencing, and narrow and wideband (HD Voice) codecs, under a software licence.
The GIII gateway
The GIII gateway is a signalling and media gateway, primarily intended for the service provider and the Emergency_service markets. The gateway enables interworking between SIP-based networks or ESInets, applications and entities, and legacy, TDM-based wired and wireless networks running CAS, ISDN or SS7 (C7) protocols. The GIII gateway is the successor to Aculab's long-established GroomerII gateway, and was introduced in the spring of 2018.
ApplianX
The ApplianX IP Gateway is an enterprise scale gateway offering interoperability between SIP-based networks and entities, TDM-based PBXs and the PSTN. The gateway includes SIP, QSIG and DPNSS interworking functionality, with Supplementary Services support, which capability is needed by the legacy enterprise PBX/IP-PBX market in the UK (with DPNSS) and elsewhere (with QSIG).
Aculab Cloud
Aculab Cloud is a telephony API platform-as-a-service that presents the user with Java, Python, C# (.NET), and RESTful APIs, enabling interactive voice, fax, speech technologies (ASR and TTS), and messaging applications to be written in high-level, general purpose programming languages. Developers can use Aculab Cloud to add telephony functions to their business applications or create telephony services or applications such as: IVR; conferencing; voicemail; broadcast fax; SMS; voice messaging services; PBXs; and predictive diallers.
VoiSentry
VoiSentry is an API-driven Speaker recognition system that enables verifying by voice in applications where there is a need to remotely authenticate callers' identities. VoiSentry was announced in 2017 and is available as 'GA' from Q2-2018.
References
Companies based in Milton Keynes
Computer telephony integration
Telecommunications equipment vendors
VoIP companies of the United Kingdom
Technology companies established in 1978
2024 mergers and acquisitions | Aculab | Technology | 1,251 |
69,824,159 | https://en.wikipedia.org/wiki/Borak%20%28cosmetic%29 | Borak or burak is a cosmetic face powder or paste that is applied on the face for protection from the sun. It is traditionally used by the Sama-Bajau people of the Philippines, Malaysia, and Indonesia.
Borak is most commonly used by Sama-Bajau women to protect the face and exposed skin areas from the harsh tropical sun at sea. Ingredients can include talcum powder, rice flour, turmeric, and other ingredients.
When dry, borak is in powder form. The powder is first soaked in water to form a paste before being applied on the face. The paste can be a yellowish color or sometimes white.
Similar pastes
In Myanmar, thanaka, a yellow-white cosmetic paste made of ground tree bark, is traditionally used for sun protection. In Madagascar, a paste of wood called masonjoany is worn for decoration as well as for sun protection.
See also
Sunscreen
Masonjoany
Thanaka
Lotion
References
Bajau culture
Cosmetics
Skin care
Powders | Borak (cosmetic) | Physics | 203 |
41,207,433 | https://en.wikipedia.org/wiki/Phantastron | A Phantastron is a type of electron tube oscillator or timer circuit. It was invented during radar development during World War 2. It was described in the Radiation Laboratory series of books, in particular the one on waveforms.
Components
Resistors
Capacitors: determine the frequency of the oscillations and filters in the circuits.
Vacuum tubes: provides a current of electrons being shot.
Top panel and turret board: the outside covers of electron tube oscillator or timer circuit.
References
External links
Video: Phantastron all vacuum tube synthesizer
Vacuum tubes | Phantastron | Physics | 119 |
74,379,021 | https://en.wikipedia.org/wiki/HD%2046509 | HD 46509, also designated as HR 2396, is a solitary star located in the northern circumpolar constellation Camelopardalis, the giraffe. It is faintly visible to the naked eye as a yellowish-orange hued point of light with an apparent magnitude of 5.86. The object is located relatively far at a distance of 791 light-years based on Gaia DR3 parallax measurements, but it is drifting closer with a heliocentric radial velocity of . At its current distance, HD 46509's brightness is diminished by interstellar extinction of 0.31 magnitudes and it has an absolute magnitude of −0.98.
HD 46509 has a stellar classification of either G9 III or K0 III, with both classes indicating that it is an evolved red giant. It is estimated to be 339 million years old, enough time for it to cool and expand to 27.3 times the radius of the Sun. HD 46509 has about 5.6 times the mass of the Sun and it radiates 399 times the luminosity of the Sun from its enlarged photosphere at an effective temperature of . It is metal enriched with an iron abundance 132% that of the Sun's ([Fe/H] = +0.12) and like most giant stars, it spins slowly with a projected rotational velocity of approximately .
References
K-type giants
Camelopardalis
BD+71 00359
046509
031946
2396 | HD 46509 | Astronomy | 311 |
2,197,956 | https://en.wikipedia.org/wiki/Thorium-232 | Thorium-232 () is the main naturally occurring isotope of thorium, with a relative abundance of 99.98%. It has a half life of 14.05 billion years, which makes it the longest-lived isotope of thorium. It decays by alpha decay to radium-228; its decay chain terminates at stable lead-208.
Thorium-232 is a fertile material; it can capture a neutron to form thorium-233, which subsequently undergoes two successive beta decays to uranium-233, which is fissile. As such, it has been used in the thorium fuel cycle in nuclear reactors; various prototype thorium-fueled reactors have been designed. However, as of 2024, thorium fuel has not been widely adopted for commercial-scale nuclear power.
Natural occurrence
The half-life of thorium-232 (14 billion years) is more than three times the age of the Earth; thorium-232 therefore occurs in nature as a primordial nuclide. Other thorium isotopes occur in nature in much smaller quantities as intermediate products in the decay chains of uranium-238, uranium-235, and thorium-232.
Some minerals that contain thorium include apatite, sphene, zircon, allanite, monazite, pyrochlore, thorite, and xenotime.
Decay
Thorium-232 has a half-life of 14 billion years and mainly decays by alpha decay to radium-228 with a decay energy of 4.0816 MeV. The decay chain follows the thorium series, which terminates at stable lead-208. The intermediates in the thorium-232 decay chain are all relatively short-lived; the longest-lived intermediate decay products are radium-228 and thorium-228, with half lives of 5.75 years and 1.91 years, respectively. All other intermediate decay products have half lives of less than four days.
The following table lists the intermediate decay products in the thorium-232 decay chain:
Rare decay modes
Although thorium-232 mainly decays by alpha decay, it also undergoes spontaneous fission 1.1% of the time. In addition, it is capable of
cluster decay, splitting into ytterbium-182, neon-24, and neon-26; the upper limit for the branching ratio of this decay mode is 2.78%. Double beta decay to uranium-232 is also theoretically possible, but has not been observed.
Use in nuclear power
Thorium-232 is not fissile; it therefore cannot be used directly as fuel in nuclear reactors. However, is fertile: it can capture a neutron to form , which undergoes beta decay with a half-life of 21.8 minutes to . This nuclide subsequently undergoes beta decay with a half-life of 27 days to form fissile .
One potential advantage of a thorium-based nuclear fuel cycle is that thorium is three times more abundant than uranium, the current fuel for commercial nuclear reactors. It is also more difficult to produce material suitable for nuclear weapons from the thorium fuel cycle compared to the uranium fuel cycle. Some proposed designs for thorium-fueled nuclear reactors include the molten salt reactor and a fast neutron reactor, among others. Although thorium-based nuclear reactors have been proposed since the 1960s and several prototype reactors have been built, there has been relatively little research on the thorium fuel cycle compared to the more established uranium fuel cycle; thorium-based nuclear power has not seen large-scale commercial use as of 2024. Nevertheless, some countries such as India have actively pursued thorium-based nuclear power.
References
Actinides
Isotopes of thorium
Fertile materials
IARC Group 1 carcinogens
Radionuclides used in radiometric dating | Thorium-232 | Chemistry | 773 |
4,028,383 | https://en.wikipedia.org/wiki/David%20Elkind | David Elkind (born March 11, 1931) is an American child psychologist and author.
Life
Elkind and his family relocated to California when he was a teenager. He studied at the University of California at Los Angeles and obtained a Bachelor of Arts degree in 1952 and Doctorate in Philosophy in 1955. David also earned an honorary Doctorate in Science at the Rhode Island College in 1987.
A professor at Tufts University, his books — The Hurried Child, The Power of Play and Miseducation — informed early childhood education professionals of the possible dangers of incorporating elementary school curriculum into the very early years of a child's life. By doing so, he argued, teachers and parents alike could lapse into developmentally inappropriate instructional and learning practices that may distort the smooth development of learning. He is associated with the belief of decline of social markers.
Professional positions
David Elkind is professor emeritus of Child Development at Tufts University in Medford, Massachusetts. He was formerly professor of Psychology, Psychiatry and Education at the University of Rochester.
Elkind obtained his doctorate at UCLA and then spent a year as David Rapaport's research assistant at the Austen Riggs Center in Stockbridge, Massachusetts. In 1964–65 he was a National Science Foundation Senior Postdoctoral Fellow at Piaget's Institut d'Epistemologie Genetique in Geneva. His research has been in the areas of perceptual, cognitive and social development where he has attempted to build upon the research and theory of Jean Piaget.
Elkind is on the editorial board of a number of scientific journals, and is a consultant to state education departments as well as to government agencies and private foundations. He lectures regularly in the United States, Canada and abroad. He has appeared on The Today Show, The CBS Morning News, Twenty/Twenty, Nightline, Donahue, and The Oprah Winfrey Show. He has been profiled in People and Boston Magazine. Elkind co-hosted the Lifetime television series, Kids These Days. He is past president of the National Association for the Education of Young Children.
Publications
Elkind's bibliography now numbers close to 500 items and includes research, theoretical articles, book chapters and eighteen books. In addition he has published more popular pieces such as children's stories in Jack and Jill, biographies of famous psychologists in the New York Times Magazine, as well as presentations of his own work in Good Housekeeping, Parade and Psychology Today. Some of his recent articles include "Computers and Young Children," "The Authority of the Brain," "The Cosmopolitan School," "On Becoming a Grandfather," and "Thanks for the Memory: The Lasting Value of True Play."
Elkind is known for his books, The Hurried Child, The Power of Play, All Grown Up and No Place to Go, and Miseducation. Grandparenting: Understanding Today's Children was published in November 1989. Parenting Your Teenager and three additional books, Images of the Young Child; Understanding Your Child and a third edition of A Sympathetic Understanding of the Child: Birth to Sixteen appeared in 1993. Ties That Stress: The New Family Imbalance was published in 1994. A second edition of All Grown Up and No Place to Go and Reinventing Childhood: Raising and Educating Children in a Changing World appeared in 1998. A third edition of The Hurried Child came out 2001 and the 25th anniversary edition was published in 2007 along with his newest book The Power of Play: Learning What Comes Naturally.
Elkind was a contributing editor to Parents Magazine.
Personal
Elkind is married to Debbie Elkind, lives on Cape Cod, and has three sons and four grandchildren.
See also
Developmental psychology
Imaginary audience
Personal fable
Genie (feral child)
References
External links
http://ase.tufts.edu/faculty-guide/faculty.asp?id=delkind a profile of Elkind
1931 births
Living people
American family and parenting writers
American psychology writers
American male non-fiction writers
Jewish American non-fiction writers
Early childhood education in the United States
Play (activity)
Tufts University faculty
Writers from Boston
University of California, Los Angeles alumni
21st-century American Jews
American child psychologists
Austen Riggs Center physicians | David Elkind | Biology | 840 |
53,097,045 | https://en.wikipedia.org/wiki/Karl-Georg%20Niebergall | Karl-Georg Niebergall (born 1961) is a German logician and philosopher and professor for logic and philosophy of language at Humboldt University of Berlin.
Biography
From 1982 Niebergall studied mathematics in Darmstadt. After that he studied logic and philosophy of science under Godehard Link and Matthias Varga von Kibéd at Ludwig Maximilian University of Munich (LMU). Niebergall received his PhD in philosophy from LMU in 1995. His PhD dissertation on ‘The metamathematics of non-axiomatized theories’ was awarded with the Stegmüller award of the German Society for Analytic Philosophy. In 1997 Niebergall was a visiting scholar at Stanford University. From 1998 he was associate professor at the department of philosophy at LMU. In 2002 Niebergall received his Habilitation with a dissertation on ‘The foundations of mathematics. Reducibility and ontology’. Since 2008, Niebergall has been professor for logic and philosophy of language at Humboldt University of Berlin.
Research
Niebergall’s research has centered on the metamathematics of formal theories related to mereology and infinity. He has also critically engaged with the works of Nelson Goodman, David Hilbert and William W. Tait.
Awards
A Stegmüller award of the German Society for Analytic Philosophy (1997) for his doctoral dissertation
References
External links
Works by Karl-Georg Niebergall (PhilPapers)
1961 births
20th-century German philosophers
21st-century German philosophers
German logicians
German philosophers of language
Mathematical logicians
Ludwig Maximilian University of Munich alumni
Academic staff of the Humboldt University of Berlin
Living people | Karl-Georg Niebergall | Mathematics | 324 |
53,416,632 | https://en.wikipedia.org/wiki/Cold%20metal%20transfer | Cold metal transfer (CMT) is a welding method that is usually performed by a welding robot. The CMT machine detects a short circuit which sends a signal that retracts the welding filler material, giving the weld time to cool before each drop is placed. This leaves a smooth weld that is stronger than that of a hotter weld. This works well on thin metal that is prone to warping and the weld burning through the material. This type of welding is more efficient than other GMAW methods when the metal is thinner than 10mm, anything thicker and the expense begins to overcome traditional welding. Welding wire is fed through the system that is controlled by a computer, the computer adjusts things such as wire feed, welding speed, and amps going through the wire. This allows precise welding of materials like steel and aluminum, with very little slag and spatter, resulting in a cleaner finish weld.
Definition
CMT is a subset of gas metal arc welding. It works by reducing the weld current and retracting the weld wire when detecting a short circuit, resulting in a drop-by-drop deposit of weld material. Developed for thin materials, CMT requires strict control of weld parameters.
History
CMT was originally intended for joining sheet metal in the automotive industry, but has expanded to thicker materials.
Application
Cold metal transfer is used to weld different types of metal with various thicknesses. This low voltage, low heat welding works well on thin sheet metal. It is also being used for thicker material where the integrity of the weld is important. When metal is overheated it affects its structural properties; CMT welding keeps the heat to a minimum, resulting in little change to the structure of the metal, and a stronger weld. Thin metal has a greater possibility of distorting when heated. During traditional GMAW welding, heat sinks or other heat protection had to be used to prevent the warping of the metal. Heat protection is not needed during the CMT process. CMT has a wide variety of applications in various industries such as small engine, automotive, and marine.
Specifications
References
External links
Cold metal transfer , Fronius welding processes
Welding
Austrian brands | Cold metal transfer | Engineering | 451 |
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