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48,790,532 | https://en.wikipedia.org/wiki/Hexamolybdenum | Hexamolybdenum is a molybdenum dominant alloy discovered during a nanomineralogy investigation of the Allende meteorite. Hexamolybdenum was discovered in a small ultrarefractory inclusion within the Allende meteorite. This inclusion has been named ACM-1. Hexamolybdenum is hexagonal, with a calculated density of 11.90 g/cm3. The new mineral was found along with allendeite. These minerals, are believed to demonstrate conditions during the early stages of the Solar System, as is the case with many CV3 carbonaceous chondrites such as the Allende meteorite. Hexamolybdenum lies on a continuum of high-temperature alloys that are found in meteorites and allows a link between osmium, ruthenium, and iron rich meteoritic alloys. The name hexamolybdenum refers to the crystal symmetry (primitive hexagonal) and the molybdenum rich composition. The Allende meteorite fell in 1969 near Pueblito de Allende, Chihuahua, Mexico.
Occurrence
Hexamolybdenum was found as nano-crystals in an ultrarefractory inclusion in the Allende meteorite. The Allende meteorite has shown to be full of new minerals, after nearly forty years it has produced one in ten of the now known minerals in meteorites. This CV3 carbonaceous chondrite was the largest ever recovered on earth and is referred to as the best-studied meteorite in history.
The inclusion has only been viewed via electron microscopy. The hexamolybdenum specimen was lost during an attempted ion probe analysis of a bordering grain. Other specimens can be found, however, in the Smithsonian Institution's National Museum of Natural History Allende section USNM 3509HC12 and in section USNM 7590 of NWA 1934, another VC3 chondrite.
It has also been reported from the NWA 1934 CV3 carbonaceous chondrite meteorite from the Erfoud region of Morocco and in the Danubian placer of Straubing, Bavaria.
Chemical composition
Hexamolybdenum is an (molybdenum, ruthenium, iron, iridium, osmium) alloy.
Appearance
Color, streak, luster, hardness, tenacity, cleavage, fracture, density, and refractive index could not be observed because the grain size was too small and the section bearing the mineral was optically thick.
See also
Classification of minerals
List of minerals
References
Hexagonal minerals
Minerals in space group 194
Native element minerals
Molybdenum minerals
Ferrous alloys
Ruthenium minerals
Iron minerals
Iridium minerals
Osmium compounds | Hexamolybdenum | Chemistry | 568 |
49,154,490 | https://en.wikipedia.org/wiki/Cericlamine | Cericlamine (INN; developmental code JO-1017) is a potent and moderately selective serotonin reuptake inhibitor (SSRI) of the amphetamine family (specifically, a derivative of phentermine, and closely related to chlorphentermine, a highly selective serotonin releasing agent) that was investigated as an antidepressant for the treatment of depression, anxiety disorders, and anorexia nervosa by Jouveinal but did not complete development and was never marketed. It reached phase III clinical trials in 1996 before development was discontinued in 1999.
According to Czech scientists, cericlamine is claimed to be part of a highly advanced “fifth generation” of antidepressants as was venlafaxine.
The daily dosage was reported to be 300mg.
See also
3,4-Dichloroamphetamine
Alaproclate
Bupropion
Chlorphentermine
Clortermine
Cloforex
Etolorex
Femoxetine
Ifoxetine
Indalpine
Methylenedioxyphentermine
Omiloxetine
Panuramine
para-Chloroamphetamine
para-Chloromethamphetamine
Phentermine
Pirandamine
Seproxetine
Viqualine
Zimelidine
References
Abandoned drugs
Antidepressants
Chlorobenzene derivatives
Dimethylamino compounds
Phentermines
Selective serotonin reuptake inhibitors | Cericlamine | Chemistry | 299 |
15,460,040 | https://en.wikipedia.org/wiki/Academy%20of%20Management | The Academy of Management is a professional association for scholars of management and organizations that was established in 1936. It publishes several academic journals, organizes conferences, and provides others forums for management professors and managers to communicate research and ideas.
Publications
The academy publishes the following academic journals:
Academy of Management Journal
Academy of Management Review
Academy of Management Perspectives (formerly Academy of Management Executive)
Academy of Management Learning and Education
Academy of Management Annals
Academy of Management Discoveries
Academy of Management Insights
The first three journals were ranked in the top 40 business journals in the world in 2006 by the Financial Times.
See also
Human resources development
Human resource management
Industrial and organizational psychology
Industrial sociology
References
External links
Management science
Human resource management publications
Professional associations based in the United States
Organizations established in 1936
Briarcliff Manor, New York
1936 establishments in the United States | Academy of Management | Biology | 163 |
49,965,272 | https://en.wikipedia.org/wiki/Carmoterol | Carmoterol (INN; development codes TA-2005 and CHF-4226) is a non-catechol experimental ultra-long-acting β adrenoreceptor agonist (ultra-LABA) that was in clinical trials before 2010 when it has been withdrawn from further development based on evidence that the compound does not possess a competitive profile.
Preliminary studies indicated duration of its effect exceeding 24 hours after inhalation of 3 μg. The pharmacologic profile of this medication included the fact its potency in isolated guinea pig trachea is greater than that of formoterol and salmeterol. It is over 100 times more selective for bronchial muscle than myocardial tissue.
References
Abandoned drugs
Long-acting beta2-adrenergic agonists
2-Quinolones
Quinolinols
Phenylethanolamines
4-Methoxyphenyl compounds | Carmoterol | Chemistry | 191 |
12,674,074 | https://en.wikipedia.org/wiki/Arrhenius%20plot | In chemical kinetics, an Arrhenius plot displays the logarithm of a reaction rate constant, ordinate axis) plotted against reciprocal of the temperature abscissa). Arrhenius plots are often used to analyze the effect of temperature on the rates of chemical reactions. For a single rate-limited thermally activated process, an Arrhenius plot gives a straight line, from which the activation energy and the pre-exponential factor can both be determined.
The Arrhenius equation can be given in the form:
where:
= rate constant
= pre-exponential factor
= (molar) activation energy
= gas constant, (, where is the Avogadro constant).
= activation energy (for a single reaction event)
= Boltzmann constant
= absolute temperature
The only difference between the two forms of the expression is the quantity used for the activation energy: the former would have the unit joule/mole, which is common in chemistry, while the latter would have the unit joule and would be for one molecular reaction event, which is common in physics. The different units are accounted for in using either the gas constant or the Boltzmann constant .
Taking the natural logarithm of the former equation gives:
When plotted in the manner described above, the value of the y-intercept (at ) will correspond to , and the slope of the line will be equal to . The values of y-intercept and slope can be determined from the experimental points using simple linear regression with a spreadsheet.
The pre-exponential factor, , is an empirical constant of proportionality which has been estimated by various theories which take into account factors such as the frequency of collision between reacting particles, their relative orientation, and the entropy of activation.
The expression represents the fraction of the molecules present in a gas which have energies equal to or in excess of activation energy at a particular temperature. In almost all practical cases, , so that this fraction is very small and increases rapidly with In consequence, the reaction rate constant increases rapidly with temperature , as shown in the direct plot of against . (Mathematically, at very high temperatures so that , would level off and approach as a limit, but this case does not occur under practical conditions.)
Worked example
Considering as example the decomposition of nitrogen dioxide into nitrogen monoxide and molecular oxygen:
Based on the red "line of best fit" plotted in the graph given above:
Points read from graph:
Slope of red line = (4.1 − 2.2) / (0.0015 − 0.00165) = −12,667
Intercept [y-value at x = 0] of red line = 4.1 + (0.0015 × 12667) = 23.1
Inserting these values into the form above:
yields:
as shown in the plot at the right.
for:
k in 10−4 cm3 mol−1 s−1
T in K
Substituting for the quotient in the exponent of :
where the approximate value for R is 8.31446 J K−1 mol−1
The activation energy of this reaction from these data is then:
See also
Arrhenius equation
Eyring equation
Polymer degradation
References
Chemical kinetics
Plots (graphics) | Arrhenius plot | Chemistry | 661 |
964,704 | https://en.wikipedia.org/wiki/Messier%2067 | Messier 67 (also known as M67 or NGC 2682) and sometimes called the King Cobra Cluster or the Golden Eye Cluster is an open cluster in the southern, equatorial half of Cancer. It was discovered by Johann Gottfried Koehler in 1779. Estimates of its age range between 3.2 and 5 billion years. Distance estimates are likewise varied, but typically are . Estimates of 855, 840, and 815 pc were established via binary star modelling and infrared color-magnitude diagram fitting.
Description
M67 is not the oldest known open cluster, several Milky Way clusters are known to be older, yet farther than M67. It is a paradigm study object in stellar evolution:
it is well-populated
has negligible amounts of dust obscuration
all its stars are at the same distance and age, save for approximately 30 anomalous blue stragglers
M67 is one of the most-studied open clusters, yet estimates of its physical parameters such as age, mass, and number of stars of a given type, vary substantially. Richer et al. estimate its age to be 4 billion years, its mass to be 1080 solar masses (), and number its white dwarfs at 150. Hurley et al. estimate its current mass to be and its initial mass to be approximately 10 times as great.
It has more than 100 stars similar to the Sun, and numerous red giants. The total star count has been estimated at well over 500. The ages and prevalence of Sun-like stars had led some astronomers to theorize it as the possible parent cluster of the Sun. However, computer simulations disagree on whether the outer Solar System would have survived an ejection from M67, and the cluster itself would probably not have survived such an ejection event.
The cluster contains no main sequence stars bluer (hotter) than spectral type F, other than perhaps some of the blue stragglers, since the brighter stars of that age have already left the main sequence. In fact, when the stars of the cluster are plotted on the Hertzsprung-Russell diagram, there is a distinct "turn-off" representing the stars which have terminated hydrogen fusion in the core and are destined to become red giants. As a cluster ages, the turn-off moves progressively down the main sequence to cooler stars.
It appears that M67 has a bias toward heavier stars. One cause of this is mass segregation, the process by which lighter stars gain speed at the expense of more massive stars during close encounters, which moves them to greater average distance from the center of the cluster or allows escape altogether.
A March 2016 joint AIP/JHU study by Barnes et al. on rotational periods of 20 Sun-like stars, measured by the effects of moving starspots on light curves, suggests that these approximately 4 billion-year old stars spin in about 26 days – like the Sun, which has a period at the equator of 25.38 days. Measurements were carried out as part of the extended K2 mission of Kepler space telescope. This reinforces the applicability of many key properties of the Sun to stars of the same size and age, a fundamental principle of modern solar and stellar physics. The authors abbreviate this as the "solar-stellar connection".
Planets
A radial velocity survey of M67 has found exoplanets around five stars in the cluster: YBP 1194, YBP 1514, YBP 401, Sand 978, and Sand 1429. A sixth star, Sand 364, was also thought to have a planet, but a follow-up study did not find evidence for it and concluded that the radial velocity variations have a non-planetary origin, likely stellar variability.
Gallery
See also
List of Messier objects
List of open clusters
Open cluster family
Open cluster remnant
References
External links
Messier 67, SEDS Messier pages
Messier 067
Messier 067
067
Messier 067
Orion–Cygnus Arm
Astronomical objects discovered in 1779 | Messier 67 | Astronomy | 817 |
57,243,146 | https://en.wikipedia.org/wiki/Wankel%20AG%20LCR%20-%20814%20TGti | The Wankel AG LCR - 814 TGti is a German Wankel aircraft engine, designed and produced by Wankel AG of Kirchberg, Saxony for use in ultralight aircraft.
Design and development
The LCR - 814 TGti engine is a twin-rotor four-stroke, displacement, liquid-cooled, fuel injected, petrol, Wankel engine design, with a toothed poly V belt reduction drive with a reduction ratio of 3:1. It employs dual electronic ignition and produces at 6000 rpm.
Specifications (LCR - 814 TGti)
See also
References
External links
Wankel AG aircraft engines
Pistonless rotary engine | Wankel AG LCR - 814 TGti | Technology | 134 |
2,439,028 | https://en.wikipedia.org/wiki/Dialed%20Number%20Identification%20Service | Dialed Number Identification Service (DNIS) is a service offered by telecommunications companies to corporate clients which identifies the originally dialed telephone number of an inbound call. The client may use this information for call routing to internal destinations or activation of special call handling.
For DNIS service, the telephone company sends a sequence of typically four to ten digits during call setup.
Direct inward dial (DID) service also provides DNIS.
For example, a company may have a different toll-free telephone number for each product line it sells, or for multilingual customer support. If a call center is handling calls for multiple product lines, the corporate telephone system that receives the call analyzes the DNIS signaling and may play an appropriate recorded greeting. For interactive voice response (IVR) systems, DNIS is used as routing information for dispatching purposes, to determine which script or service should be activated based on the number that was dialed to reach the IVR platform.
In the United States, DNIS is commonly provided for 800- and 900-services.
See also
Automatic number identification
References
Authentication methods
Telephone numbers | Dialed Number Identification Service | Mathematics | 221 |
154,242 | https://en.wikipedia.org/wiki/PH%20meter | A pH meter is a scientific instrument that measures the hydrogen-ion activity in water-based solutions, indicating its acidity or alkalinity expressed as pH. The pH meter measures the difference in electrical potential between a pH electrode and a reference electrode, and so the pH meter is sometimes referred to as a "potentiometric pH meter". The difference in electrical potential relates to the acidity or pH of the solution. Testing of pH via pH meters (pH-metry) is used in many applications ranging from laboratory experimentation to quality control.
Applications
The rate and outcome of chemical reactions taking place in water often depends on the acidity of the water, and it is therefore useful to know the acidity of the water, typically measured by means of a pH meter. Knowledge of pH is useful or critical in many situations, including chemical laboratory analyses. pH meters are used for soil measurements in agriculture, water quality for municipal water supplies, swimming pools, environmental remediation; brewing of wine or beer; manufacturing, healthcare and clinical applications such as blood chemistry; and many other applications.
Advances in the instrumentation and in detection have expanded the number of applications in which pH measurements can be conducted. The devices have been miniaturized, enabling direct measurement of pH inside of living cells. In addition to measuring the pH of liquids, specially designed electrodes are available to measure the pH of semi-solid substances, such as foods. These have tips suitable for piercing semi-solids, have electrode materials compatible with ingredients in food, and are resistant to clogging.
Design and use
Principle of operation
Potentiometric pH meters measure the voltage between two electrodes and display the result converted into the corresponding pH value. They comprise a simple electronic amplifier and a pair of electrodes, or alternatively a combination electrode, and some form of display calibrated in pH units. It usually has a glass electrode and a reference electrode, or a combination electrode. The electrodes, or probes, are inserted into the solution to be tested. pH meters may also be based on the antimony electrode (typically used for rough conditions) or the quinhydrone electrode.
In order to accurately measure the potential difference between the two sides of the glass membrane reference electrode, typically a silver chloride electrode or calomel electrode are required on each side of the membrane. Their purpose is to measure changes in the potential on their respective side. One is built into the glass electrode. The other, which makes contact with the test solution through a porous plug, may be a separate reference electrode or may be built into a combination electrode. The resulting voltage will be the potential difference between the two sides of the glass membrane possibly offset by some difference between the two reference electrodes, that can be compensated for. The article on the glass electrode has a good description and figure.
The design of the electrodes is the key part: These are rod-like structures usually made of glass, with a bulb containing the sensor at the bottom. The glass electrode for measuring the pH has a glass bulb specifically designed to be selective to hydrogen-ion concentration. On immersion in the solution to be tested, hydrogen ions in the test solution exchange for other positively charged ions on the glass bulb, creating an electrochemical potential across the bulb. The electronic amplifier detects the difference in electrical potential between the two electrodes generated in the measurement and converts the potential difference to pH units. The magnitude of the electrochemical potential across the glass bulb is linearly related to the pH according to the Nernst equation.
The reference electrode is insensitive to the pH of the solution, being composed of a metallic conductor, which connects to the display. This conductor is immersed in an electrolyte solution, typically potassium chloride, which comes into contact with the test solution through a porous ceramic membrane. The display consists of a voltmeter, which displays voltage in units of pH.
On immersion of the glass electrode and the reference electrode in the test solution, an electrical circuit is completed, in which there is a potential difference created and detected by the voltmeter. The circuit can be thought of as going from the conductive element of the reference electrode to the surrounding potassium-chloride solution, through the ceramic membrane to the test solution, the hydrogen-ion-selective glass of the glass electrode, to the solution inside the glass electrode, to the silver of the glass electrode, and finally the voltmeter of the display device. The voltage varies from test solution to test solution depending on the potential difference created by the difference in hydrogen-ion concentrations on each side of the glass membrane between the test solution and the solution inside the glass electrode. All other potential differences in the circuit do not vary with pH and are corrected for by means of the calibration.
For simplicity, many pH meters use a combination probe, constructed with the glass electrode and the reference electrode contained within a single probe. A detailed description of combination electrodes is given in the article on glass electrodes.
The pH meter is calibrated with solutions of known pH, typically before each use, to ensure accuracy of measurement. To measure the pH of a solution, the electrodes are used as probes, which are dipped into the test solutions and held there sufficiently long for the hydrogen ions in the test solution to equilibrate with the ions on the surface of the bulb on the glass electrode. This equilibration provides a stable pH measurement.
pH electrode and reference electrode design
Details of the fabrication and resulting microstructure of the glass membrane of the pH electrode are maintained as trade secrets by the manufacturers. However, certain aspects of design are published. Glass is a solid electrolyte, for which alkali-metal ions can carry current. The pH-sensitive glass membrane is generally spherical to simplify the manufacture of a uniform membrane. These membranes are up to 0.4 millimeters in thickness, thicker than original designs, so as to render the probes durable. The glass has silicate chemical functionality on its surface, which provides binding sites for alkali-metal ions and hydrogen ions from the solutions. This provides an ion-exchange capacity in the range of 10−6 to 10−8 mol/cm2. Selectivity for hydrogen ions (H+) arises from a balance of ionic charge, volume requirements versus other ions, and the coordination number of other ions. Electrode manufacturers have developed compositions that suitably balance these factors, most notably lithium glass.
The silver chloride electrode is most commonly used as a reference electrode in pH meters, although some designs use the saturated calomel electrode. The silver chloride electrode is simple to manufacture and provides high reproducibility. The reference electrode usually consists of a platinum wire that has contact with a silver/silver chloride mixture, which is immersed in a potassium chloride solution. There is a ceramic plug, which serves as a contact to the test solution, providing low resistance while preventing mixing of the two solutions.
With these electrode designs, the voltmeter is detecting potential differences of ±1400 millivolts. The electrodes are further designed to rapidly equilibrate with test solutions to facilitate ease of use. The equilibration times are typically less than one second, although equilibration times increase as the electrodes age.
Maintenance
Because of the sensitivity of the electrodes to contaminants, cleanliness of the probes is essential for accuracy and precision. Probes are generally kept moist when not in use with a medium appropriate for the particular probe, which is typically an aqueous solution available from probe manufacturers. Probe manufacturers provide instructions for cleaning and maintaining their probe designs. For illustration, one maker of laboratory-grade pH gives cleaning instructions for specific contaminants: general cleaning (15-minute soak in a solution of bleach and detergent), salt (hydrochloric acid solution followed by sodium hydroxide and water), grease (detergent or methanol), clogged reference junction (KCl solution), protein deposits (pepsin and HCl, 1% solution), and air bubbles.
Calibration and operation
The German Institute for Standardization publishes a standard for pH measurement using pH meters, DIN 19263.
Very precise measurements necessitate that the pH meter is calibrated before each measurement. More typically calibration is performed once per day of operation. Calibration is needed because the glass electrode does not give reproducible electrostatic potentials over longer periods of time.
Consistent with principles of good laboratory practice, calibration is performed with at least two standard buffer solutions that span the range of pH values to be measured. For general purposes, buffers at pH 4.00 and pH 10.00 are suitable. The pH meter has one calibration control to set the meter reading equal to the value of the first standard buffer and a second control to adjust the meter reading to the value of the second buffer. A third control allows the temperature to be set. Standard buffer sachets, available from a variety of suppliers, usually document the temperature dependence of the buffer control. More precise measurements sometimes require calibration at three different pH values. Some pH meters provide built-in temperature-coefficient correction, with temperature thermocouples in the electrode probes. The calibration process correlates the voltage produced by the probe (approximately 0.06 volts per pH unit) with the pH scale. Good laboratory practice dictates that, after each measurement, the probes are rinsed with distilled water or deionized water to remove any traces of the solution being measured, blotted with a scientific wipe to absorb any remaining water, which could dilute the sample and thus alter the reading, and then immersed in a storage solution suitable for the particular probe type.
Types of pH meters
In general there are three major categories of pH meters. Benchtop pH meters are often used in laboratories and are used to measure samples which are brought to the pH meter for analysis. Portable, or field pH meters, are handheld pH meters that are used to take the pH of a sample in a field or production site. In-line or in situ pH meters, also called pH analyzers, are used to measure pH continuously in a process, and can stand-alone, or be connected to a higher level information system for process control.
pH meters range from simple and inexpensive pen-like devices to complex and expensive laboratory instruments with computer interfaces and several inputs for indicator and temperature measurements to be entered to adjust for the variation in pH caused by temperature. The output can be digital or analog, and the devices can be battery-powered or rely on line power. Some versions use telemetry to connect the electrodes to the voltmeter display device.
Specialty meters and probes are available for use in special applications, such as harsh environments and biological microenvironments. There are also holographic pH sensors, which allow pH measurement colorimetrically, making use of the variety of pH indicators that are available. Additionally, there are commercially available pH meters based on solid state electrodes, rather than conventional glass electrodes.
History
The concept of pH was defined in 1909 by S. P. L. Sørensen, and electrodes were used for pH measurement in the 1920s.
In October 1934, Arnold Orville Beckman registered the first patent for a complete chemical instrument for the measurement of pH, U.S. Patent No. 2,058,761, for his "acidimeter", later renamed the pH meter. Beckman developed the prototype as an assistant professor of chemistry at the California Institute of Technology, when asked to devise a quick and accurate method for measuring the acidity of lemon juice for the California Fruit Growers Exchange (Sunkist).
On April 8, 1935, Beckman's renamed National Technical Laboratories focused on the manufacture of scientific instruments, with the Arthur H. Thomas Company as a distributor for its pH meter. In its first full year of sales, 1936, the company sold 444 pH meters for $60,000 in sales. In years to come, the company sold millions of the units. In 2004 the Beckman pH meter was designated an ACS National Historic Chemical Landmark in recognition of its significance as the first commercially successful electronic pH meter.
The Radiometer Corporation of Denmark was founded in 1935, and began marketing a pH meter for medical use around 1936, but "the development of automatic pH-meters for industrial purposes was neglected. Instead American instrument makers successfully developed industrial pH-meters with a wide variety of applications, such as in breweries, paper works, alum works, and water treatment systems."
In the 1940s the electrodes for pH meters were often difficult to make, or unreliable due to brittle glass. Dr. Werner Ingold began to industrialize the production of single-rod measuring cells, a combination of measurement and reference electrode in one construction unit, which led to broader acceptance in a wide range of industries including pharmaceutical production.
Beckman marketed a portable "Pocket pH Meter" as early as 1956, but it did not have a digital read-out.
In the 1970s Jenco Electronics of Taiwan designed and manufactured the first portable digital pH meter. This meter was sold under the label of the Cole-Parmer Corporation.
Building a pH meter
Specialized manufacturing is required for the electrodes, and details of their design and construction are typically trade secrets. However, with purchase of suitable electrodes, a standard multimeter can be used to complete the construction of the pH meter. However, commercial suppliers offer voltmeter displays that simplify use, including calibration and temperature compensation.
See also
Antimony electrode
Ion-selective electrodes
ISFET pH electrode
Potentiometry
Quinhydrone electrode
Saturated calomel electrode
Silver chloride electrode
Standard hydrogen electrode
References
External links
Introduction to pH measurement – Overview of pH and pH measurement at the Omega Engineering website
Development of the Beckman pH Meter – National Historic Chemical Landmark of the American Chemical Society
pH Measurement Handbook - A publication of the Thermo-Scientific Co.
Acid–base chemistry
Electrochemistry
Measuring instruments
Scientific instruments | PH meter | Chemistry,Technology,Engineering | 2,872 |
13,955,557 | https://en.wikipedia.org/wiki/Mechanostat | The Mechanostat is a term describing the way in which mechanical loading influences bone structure by changing the mass (amount of bone) and architecture (its arrangement) to provide a structure that resists habitual loads with an economical amount of material. As changes in the skeleton are accomplished by the processes of formation (bone growth) and resorption (bone loss), the mechanostat models the effect of influences on the skeleton by those processes, through their effector cells, osteocytes, osteoblasts, and osteoclasts. The term was invented by Harold Frost: an orthopaedic surgeon and researcher described extensively in articles referring to Frost and Webster Jee's Utah Paradigm of Skeletal Physiology in the 1960s. The Mechanostat is often defined as a practical description of Wolff's law described by Julius Wolff (1836–1902), but this is not completely accurate. Wolff wrote his treatises on bone after images of bone sections were described by Culmann and von Meyer, who suggested that the arrangement of the struts (trabeculae) at the ends of the bones were aligned with the stresses experienced by the bone. It has since been established that the static methods used for those calculations of lines of stress were inappropriate for work on what were, in effect, curved beams, a finding described by Lance Lanyon, a leading researcher in the area as "a triumph of a good idea over mathematics." While Wolff pulled together the work of Culmann and von Meyer, it was the French scientist Roux, who first used the term "functional adaptation" to describe the way that the skeleton optimized itself for its function, though Wolff is credited by many for that.
According to the Mechanostat, bone growth and bone loss is stimulated by the local, mechanical, elastic deformation of bone. The reason for the elastic deformation of bone is the peak forces caused by muscles (e.g. measurable using mechanography). The adaptation (feed-back control loop) of bone according to the maximum forces is considered to be a lifelong process. Hence, bone adapts its mechanical properties according to the needed mechanical function: bone mass, bone geometry, and bone strength (see also Stress-strain index, SSI) adapt to everyday usage/needs. "Maximal force" in this context is a simplification of the real input to bone that initiates adaptive changes. While the magnitude of a force (the weight of a load for example) is an important determinant of its effect on the skeleton, it is not the only one. The rate of application of force is also critical. Slow application of force over several seconds is not experienced by bone cells as a stimulus, but they are sensitive to very rapid application of forces (such as impacts) even of lower magnitude. High frequency vibration of bone at very low magnitudes is thought to stimulate changes, but the research in the area is not completely unequivocal. It is clear that bones respond better to loading/exercise with gaps between individual events, so that two loads separated by ten seconds of rest are more potent stimuli than ten loads within the same ten seconds.
Due to this control loop, there is a linear relationship in the healthy body between muscle cross sectional area (as a surrogate for typical maximum forces the muscle is able to produce under physiological conditions) and the bone cross sectional area (as a surrogate for bone strength).
These relations are of immense importance, especially for conditions of bone loss like osteoporosis, since an adapted training utilizing the needed maximum forces on the bone can be used to stimulate bone growth and thereby prevent or help to minimize bone loss. An example for such an efficient training is vibration training or whole body vibration.
Modeling and remodeling
Frost defined four regions of elastic bone deformation which result in different consequences on the control loop:
Disuse: Strain < circa 800μStrain: Remodeling (bone adaptation and bone repair) Bone mass and bone strength is reduced.
Adapted State: strain between circa 800μStrain and circa 1500μStrain: Remodeling (bone repair) Bone mass and bone strength stays constant (homeostasis: bone resorption=bone formation).
Overload: Strain > circa 1500μStrain: Modeling (bone growth): bone mass and bone strength is increased.
Fracture: Strain > circa 15000μStrain: Maximum elastic deformation exceeded, causing bone fracture.
According to this, a typical bone (e.g., the tibia) has a security margin of about 5 to 7 between typical load (2000 to 3000 μStrain) and fracture load (about 15000μStrain).
The comments above are all one part of how the skeleton responds to loading, because the different bones of the skeleton have a range of habitual strain environments (encompassing magnitude, rate, frequency, rest periods, etc.), and they are not uniform. The numbers in the table are only theoretical and may reflect the response of the center of a long bone under specific circumstances. Other parts of the same bone and other bones in the same individual experience different loading and adapt to them despite different thresholds between disuse, maintenance and adaptive formation. Furthermore, bone structure is controlled by a complex series of different influences, such as calcium status, the effects of hormones, age, diet, sex, disease, and pharmaceuticals. A bone experiencing what would in some circumstances be seen as a stimulus to form more material could either be maintained at a constant level where circulating calcium was low, or the same loading could merely temper the amount of resorption experienced in an old person with a bone-wasting disease.
Unit: Strain E
The elastic deformation of bone is measured in μStrain. 1000μStrain = 0.1% change of length of the bone.
Strain E at length l and change of length Δl:
It has to be considered that bone strength is highly dependent on geometry and direction of the acting forces in relation to this geometry. The fracture load for axial forces of the tibia for example is about 50 to 60 times the body weight. The fracture load for forces perpendicular to the axial direction is about 10 times lower.
Different types of bones can have different modeling and remodeling thresholds. The modeling threshold of the tibia is about 1500 μStrain (0.15% change of length), while the modeling threshold for parts of the bones of the skull is quite different. Some parts of the skull such as the lower jaw (mandible) experience significant forces and strains during chewing, but the dome of the cranium must remain strong to protect the brain, even if it does not experience what would be seen as stimulating strains. In one study where the strains were measured in the skull of a live human, it was shown that strains in the skull never exceeded 1/10 of the peak strain in the tibia of the same individual, with similar differences in strain rates. This suggests that either bones of the skull are very sensitive to extremely low strains, or that the "genetic baseline" amount of bone in the skull in what is effectively disuse is not modified by the effects of loading. Whether the skulls of boxers are thicker than normal individuals is an intriguing question that has not been answered.
Since the physical, material properties of bone are not altered in the different bone types of the body, this difference in modeling threshold results in an increased bone mass and bone strength, thus in an increased safety factor (relation between fracture load and typical loads) for the skull compared to the tibia. A lower modeling threshold means that the same typical daily forces result in a ‘thicker’ and hence stronger bone at the skull.
Examples
Typical examples of the influence of maximum forces and the resulting elastic deformations on bone growth or bone loss are extended flights of astronauts and cosmonauts, as well as patients with paraplegia due to an accident. Extended periods in free fall do not lead to loss of bone from the skull, providing support to the idea that its bone is maintained by a genetic not a mechanical influence (skull bone often increases in long term space flights, something thought to be related to fluid shifts within the body).
A paraplegic patient in a wheelchair who is using his arms but not his legs will suffer massive muscle and bone loss in only his legs, due to the lack of usage of the legs. However, the muscles and bones of the arms which are used every day will stay the same, or might even increase, depending on the usage.
The same effect can be observed for long flight astronauts or cosmonauts. While they still use their arms in an almost normal manner, due to the lack of gravity in space there are no maximum forces induced on the bones of the legs. On earth, long term players of racquet sports experience similar effects, where the dominant arm can have 30% more bone than the other due to the asymmetric applications of force.
Harold Frost applied the Mechanostat model not only to skeletal tissues, but also to fibrous, collagenous connective tissues, such as ligaments, tendons, and fascia. He described their adaptational responsiveness to strain in his "stretch-hypertrophy rule":
"Intermittent stretch causes collagenous tissues to hypertrophy until the resulting increase in strength reduces elongation in tension to some minimum level".
Similar to the responsiveness of bony tissues, this adaptational response occurs only if the mechanical strain exceeds a certain threshold value. Harold Frost proposed that for dense, collagenous connective tissues, the related threshold value is around 4% strain elongation.
Literature
External links
ISMNI – International Society of Musculoskeletal and Neuronal Interactions
Physiology
Osteology | Mechanostat | Biology | 2,004 |
58,104,462 | https://en.wikipedia.org/wiki/Lysenin | Lysenin is a pore-forming toxin (PFT) present in the coelomic fluid of the earthworm Eisenia fetida. Pore-forming toxins are a group of proteins that act as virulence factors of several pathogenic bacteria. Lysenin proteins are chiefly involved in the defense against cellular pathogens. Following the general mechanism of action of PFTs lysenin is segregated as a soluble monomer that binds specifically to a membrane receptor, sphingomyelin in the case of lysenin. After attaching to the membrane, the oligomerization begins, resulting in a nonamer on top of membrane, known as a prepore. After a conformational change, which could be triggered by a decrease of pH, the oligomer is inserted into the membrane in the so-called pore state.
Monomer
Lysenin is a protein produced in the coelomocyte-leucocytes of the earthworm Eisenia fetida. This protein was first isolated from the coelomic fluid in 1996 and named lysenin (from lysis and Eisenia). Lysenin is a relatively small water-soluble molecule with a molecular weight of 33 kDa. Using X-ray crystallography, lysenin was classified as a member of the Aerolysin protein family by structure and function. Structurally, each lysenin monomer consists of a receptor binding domain (grey globular part on right of Figure 1) and a Pore Forming Module (PFM); domains shared throughout the aerolysin family. The lysenin receptor binding domain shows three sphingomyelin binding motifs. The Pore Forming Module contains the regions that undergo large conformational changes to become the β-barrel in the pore.
Membrane receptors
The natural membrane target of lysenin is an animal plasma membrane lipid called sphingomyelin located mainly in its outer leaflet, involving at least three of its phosphatidylcholines (PC) groups. Sphingomyelin is usually found associated with cholesterol in lipid rafts. Cholesterol, which enhances oligomerization, provides a stable platform with high lateral mobility where monomer-monomer encounters are more probable. PFTs have shown to be able to remodel the membrane structure, sometimes even mixing lipid phases.
The region of the lysenin pore β-barrel expected to be immersed in the hydrophobic region of the membrane is the 'detergent belt', the 3.2 nm high region occupied by detergent in Cryogenic Electron Microscopy (Cryo-EM) studies of the pore. On the other hand, sphingomyelin/Cholesterol bilayers are about 4.5 nm height. This difference in height between the detergent belt and the sphingomyelin/cholesterol bilayer implies a bend of the membrane in the region surrounding the pore, called negative mismatch. This bending results in a net attraction between pores that induce pores aggregation.
Binding, oligomerization and insertion
Membrane binding is a requisite to initiate PFT oligomerization. Lysenin monomers bind specifically to sphingomyelin via the receptor binding domain. The final lysenin oligomer is constituted by nine monomers without quantified deviations. When lysenin monomers bind to sphingomyelin-enriched membrane regions, they provide a stable platform with a high lateral mobility, hence favouring the oligomerization. As with most PFTs, lysenin oligomerization occurs in a two-step process, as was recently imaged.
The process begins with monomers being adsorbed into the membrane by specific interactions, resulting in an increased concentration of monomers. This increase is promoted by the small area where the membrane receptor accumulates since the majority of PFT membrane receptors are associated with lipid rafts. Another side effect, aside from the increase of monomer concentration, is the monomer-monomer interaction. This interaction increases lysenin oligomerization. After a critical threshold concentration is reached, several oligomers are formed simultaneously, although sometimes these are incomplete. In contrast to PFTs of the cholesterol-dependent cytolysin family, the transition from incomplete lysenin oligomers to complete oligomers has not been observed.
A complete oligomerization results in the so-called prepore state, a structure on the membrane. Determining the prepore's structure by X-ray or Cryo-EM is a challenging process that so far has not produced any results. The only available information about the prepore structure was provided by Atomic Force Microscopy (AFM). The measured prepore height was 90 Å; and the width 118 Å, with an inner pore of 50 Å. A model of the prepore was built aligning the monomer structure () with the pore structure () by their receptor-binding domains (residues 160 to 297). A recent study in aerolysin suggests that the currently accepted model for the lysenin prepore should be revisited, according to the new available data on the aerolysin insertion.
A conformational change transforms the PFM into the transmembrane β-barrel, leading to the pore state. The trigger mechanism for the prepore-to-pore transition in lysenin depends on three glutamic acid residues (E92, E94 and E97), and is activated by a decrease in pH, from physiological conditions to the acidic conditions reached after endocytosis, or an increase in calcium extracellular concentration. These three glutamic acids are located in an α-helix that forms part of the PFM, and glutamic acids are found in aerolysin family members in its PFMs. Such a conformational change produces a decrease in the oligomer height of 2.5 nm according to AFM measurements. The main dimensions, using lysenin pore X-ray structure, are height 97 Å, width 115 Å and the inner pore of 30 Å. However, complete oligomerization into the nonamer is not a requisite for the insertion, since incomplete oligomers in the pore state can be found. The prepore to pore transition can be blocked in crowded conditions, a mechanism that could be general to all β-PFTs. The first hint of crowding effect on prepore to pore transition was given by congestion effects in electrophysiology experiments.
Insertion consequences
The ultimate consequences of lysenin pore formation are not well documented; however, it is thought to induce apoptosis via three possible hypotheses:
Breaking the sphingomyelin asymmetry between the two leaflets of the lipid bilayer by punching holes in the membrane and inducing lipid flip-flop (reorientation of a lipid from one leaflet of a membrane bilayer to the other).
Increasing the calcium concentration in the cytoplasm.
Decreasing the potassium concentration in the cytoplasm.
Biological role
The biological role of lysenin remains unknown. It has been suggested that lysenin may play a role as a defence mechanism against attackers such as bacteria, fungi or small invertebrates. However, lysenin's activity is dependent upon binding to sphingomyelin, which is not present in the membranes of bacteria, fungi or most invertebrates. Rather, sphingomyelin is mainly present in the plasma membrane of chordates. Another hypothesis is that the earthworm, which is able to expel coelomic fluid under stress, generates an avoidance behaviour to its vertebrate predators (such as birds, hedgehogs or moles). If that is the case, the expelled lysenin might be more effective if the coelomic fluid reaches the eye, where the concentration of sphingomyelin is ten times higher than in other body organs. A complementary hypothesis is that the pungent smell of the coelomic fluid - giving the earthworm its specific epithet foetida - is an anti-predator adaptation. However, it remains unknown whether lysenin contributes to avoidance of Eisenia by predators.
Applications
Lysenin's conductive properties have been studied for years. Like most pore-forming toxins, lysenin forms a non-specific channel that is permeable to ions, small molecules, and small peptides. There have also been over three decades of studies into finding suitable pores for converting into nanopore sequencing systems that can have their conductive properties tuned by point mutation. Owing to its binding affinity for sphingomyelin, lysenin (or just the receptor binding domain) has been used as a fluorescence marker to detect the sphingomyelin domain in membranes.
References
External links
https://www.theses.fr/2017AIXM0124
Protein toxins | Lysenin | Chemistry | 1,853 |
51,735,144 | https://en.wikipedia.org/wiki/Amanita%20umbrinolutea | Amanita umbrinolutea, also known as the umber-zoned ringless amanita, is a species of the genus Amanita.
Description
The cap of A. umbrinolutea is usually free of volval remnants, wide, at first conico-paraboloid, then somewhat campanulate to convex and finally planar, umbonate, with a strongly striate margin (occupying around 25–35% of the cap's radius). The cap is often dark in the center, then pale, then dark over the inner edges of the lamellae and on the ridges between the marginal striations; it can at other times be pallid in the center, but strongly zonate; the pigmentation intensity varies, with the center ranging from umber to grayish umber-brown to beige or pale grayish brown. The gills are free, crowded, off-white to sordid pale cream in mass, and up to broad; the short gills are truncate, vary in length, and are scattered and unevenly distributed.
The stem is × 6–11 mm, pale cream to pale beige or isabella color or pale grayish brown, with a faint appressed zigzag girdles of fibrils, with a fleshy membranous sack-like volva at the base. The high volva is attached to the bottom 5 mm or so of the stipe. The spores measure 10.5–13.4 × 9.5–12.5 (1.05–1.34 x 0.95–1.25 cm) μm and are subglobose (infrequently either globose or broadly ellipsoid) and inamyloid. Clamps are absent from the bases of basidia.
Distribution and habitat
A. umbrinolutea is widely distributed in Europe, with its range extending eastward at least to around northwestern Pakistan and North India. Known specimens have examined have all been found in association with conifers (including pine and spruce).
See also
List of Amanita species
References
Umbrinolutea
Fungus species | Amanita umbrinolutea | Biology | 448 |
12,507,808 | https://en.wikipedia.org/wiki/Mauremys%20pritchardi | Mauremys pritchardi is an interspecific hybrid turtle in the family Geoemydidae. M. pritchardi, described to be from Myanmar (where neither of the parental species occurs apparently), has been found in the wild in China and Japan, and is produced to some extent in Chinese turtle farms. It was listed as data deficient in the IUCN Red List before its actual origin became known.
The parents of this hybrid are the Chinese pond turtle (Mauremys reevesii ) and the Asian yellow pond turtle (Mauremys mutica). While it is not unusual for perfectly valid geoemydid species to arise from hybridization, recognition as a species would require that the hybrids be fertile and constitute a phenotypically distinct and self-sustaining lineage. This does not yet appear to be the case in this "species" as recently (Kosukawa et al. 2006) a population of these turtles has been found in Japan. The hybrid offspring are perfectly fertile, which is not the case in Mauremys iversoni for example, another intergeneric hybrid, and have been bred in captivity already, with all juveniles resembling their parents (and not the parental species) perfectly as well. Genetic studies verify its hybrid origin but scientists are unsure of the time of creation. According to Wink et al. 2001, it might well be a very ancient hybrid, while Parham et al. 2001 suppose that it is of rather recent origin.
Etymology
The specific name, pritchardi, is in honour of British herpetologist Peter Pritchard.
See also
Fujian pond turtle
Ocadia glyphistoma
Ocadia philippeni
Cuora serrata
References
Further reading
McCord, William P. (1997). "Mauremys pritchardi, a new Batagurid turtle from Myanmar and Yunnan, China". Chelonian Conserv. Biol. 2 (4): 555–562.
External links
(2005). "On the hybridisation between two distantly related Asian turtles (Testudines: Sacalia × Mauremys)". Salamandra 41: 21–26. PDF fulltext.
(2001). "New Chinese turtles: endangered or invalid? A reassessment of two species using mitochondrial DNA, allozyme electrophoresis and known-locality specimens". Animal Conservation 4 (4): 357–367. HTML abstract Erratum: Animal Conservation 5 (1): 86. HTML abstract
Mauremys
Taxonomy articles created by Polbot
Hybrid animals | Mauremys pritchardi | Biology | 535 |
23,824,086 | https://en.wikipedia.org/wiki/Holon%20%28physics%29 | Holons are one of three quasi-particles, along with spinons and orbitons, that electrons in solids are able to split into during the process of spin–charge separation, when extremely tightly confined at temperatures close to absolute zero. The electron can always be theoretically considered as a bound state of the three, with the spinon carrying the spin of the electron, the orbiton carrying the orbital location and the holon carrying the charge, but in certain conditions they can become deconfined and behave as independent particles.
Overview
Electrons, being fermions, repel each other due to the Pauli exclusion principle. As a result, in order to move past each other in an extremely crowded environment, they are forced to modify their behavior. Research published in July 2009 by the University of Cambridge and the University of Birmingham in Britain showed that electrons could jump past each other by quantum tunneling, and in order to do so will separate into two particles, named spinons and holons by the researchers.
Notes
General References
See also
Condensed matter physics
Tomonaga–Luttinger liquid
Quasiparticles | Holon (physics) | Physics,Materials_science | 226 |
1,571,800 | https://en.wikipedia.org/wiki/HD%2010647 | HD 10647 (q1 Eridani) is a 6th-magnitude yellow-white dwarf star, 57 light-years away in the constellation of Eridanus. The star is visible to the unaided eye under very dark skies. It is slightly hotter and more luminous than the Sun, and at 1.75 billion years old, it is also younger. An extrasolar planet was discovered orbiting this star in 2003.
Planetary system
In 2003, Michel Mayor's team announced the discovery of a new planet, HD 10647 b, in Paris at the XIX IAP Colloquium Extrasolar Planets: Today & Tomorrow* . The Anglo-Australian Planet Search team initially did not detect the planet in 2004, though a solution was made by 2006. The CORALIE data was finally published in 2013.
The IRAS infrared space telescope detected an excess of infrared radiation from the star, indicating a possible circumstellar disk. Out of the 300 nearest Sun-like stars, the disk has the highest fractional luminosity out of all of them. It is unusually bright, but not unusually massive; the lower bound of the mass is 8 times that of the Earth.
The inclination of the disk is relatively high, and the disk is asymmetrical, being more extended in the northeast direction than the southwest. It extends from 34 astronomical units (AU) at the inner edge to 134 AU at the outer edge. The inner edge is sharp, suggesting the existence of a planet that carved out the edge. HD 10647 b, with a semimajor axis of about 2 AU, is too far to be responsible. However, other potential planets may be responsible for this feature.
There is some evidence for an additional, warm asteroid belt-like component further in, at 3 to 10 AU away from the star.
References
External links
Sky Map: HD 10647
Eridani, Q1
Eridanus (constellation)
010647
007978
0506
F-type main-sequence stars
Eridani, 5
Durchmusterung objects
3109
Planetary systems with one confirmed planet | HD 10647 | Astronomy | 430 |
7,685,674 | https://en.wikipedia.org/wiki/Soakage%20%28source%20of%20water%29 | A soakage, or soak, is a source of water in Australian deserts.
It is called thus because the water generally seeps into the sand, and is stored below, sometimes as part of an ephemeral river or creek.
Aboriginal water source
Soakages were traditionally important sources of water for Aboriginal Australians in the desert, being the most dependable source in times of drought in Australia.
Aboriginal peoples would scoop out the sand or mud using a coolamon or woomera, often to a depth of several metres, until clean water gathered in the base of the hole. Knowing the precise location of each soakage was extremely valuable knowledge. It is also sometimes called a native well.
Anthropologist Donald Thomson wrote:
Cleaning and maintaining the well
Wells were covered to keep them free from fouling by animals. This involved blocking the well with dead branches and uprooted trees. When the wells fell into disrepair, people would bail the well, using the coolamon to throw slush against the wall. This would set like a cement wash and help to hold loose sand, preventing it from falling into the water.
Wells could be up to fifteen feet deep, with small toe holds cut into the walls.
Recording well locations
Donald Thomson writes:
White explorers and the wells
In the nineteenth century, both Warburton and Carnegie recorded that they had run down Aboriginal residents with camels and captured and chained them to compel them to reveal their secret sources of water. This action left a lasting impression on Aboriginal residents of desert regions, who would have handed accounts of this down through successive generations.
In the 1930s, when H. H. Finlayson made his journeys through the desert by camel, he noted that a gelded male camel, after a hard three-and-a-half-day journey in intense heat without water, drank by actual measure without stopping, and fifteen minutes later, another .
This sheds light on the resentment built up among the Aboriginal population against explorers for the exploitation and, by enlarging well entrances and digging out springs, the devastation of their precious water supplies to satisfy camel teams.
Don McLeod (Aboriginal rights activist, see Pilbara) also tells a story of clashes over soak water at the time of the gold rushes in Western Australia:
McLeod relates a story told to him by an old prospector by the name of Long, observing an Aboriginal man and woman:
See also
Bindibu Expedition
Canning Stock Route
Claypan
Groundwater
Waterhole
Soak dike
References
External links
Us Mob - Finding water in the desert
Geography of Australia
History of Indigenous Australians
Australian Aboriginal bushcraft
Australian English
Water
Hydrology
Aquifers
Water wells
Exploration of Western Australia
Agriculture in Australia
Water supply and sanitation in Australia | Soakage (source of water) | Chemistry,Engineering,Environmental_science | 549 |
70,798,785 | https://en.wikipedia.org/wiki/List%20of%20Red%20Lists | This list is of Red Lists, Red Data Books, and related initiatives that assess and document the extinction risk of species, whether on an international or more local level (regional Red Lists). The IUCN has published a set of Guidelines for Application of the IUCN Red List Criteria at Regional and National Levels and at least 113 countries have produced their own Red Lists. Below, where a particular article or set of articles on a foreign-language Wikipedia provides fuller coverage, a link is provided.
International
International Union for Conservation of Nature
IUCN Red List
European Red List
Angola
: Lista Vermelha de Espécies de Angola, published by the Ministério do Ambiente
Armenia
: ԿԱՐՄԻՐ ԳԻՐՔ, published by the Ministry of Environment;
Australia
: Species Profile and Threats Database, published by the Department of Agriculture, Water and the Environment
Azerbaijan
:
Belarus
:
Brazil
: Livro Vermelho da Fauna Brasileira Ameaçada de Extinção, published by the Chico Mendes Institute for Biodiversity Conservation
Bulgaria
: Червена книга на Република България (Red Data Book of the Republic of Bulgaria), published by the Bulgarian Academy of Sciences and Ministry of Environment and Water;
Canada
: Species at risk public registry, published by the Government of Canada
China
: 中国生物多样性红色名录, published by the Ministry of Ecology and Environment: 脊椎动物卷 (vertebrates) 高等植物卷 (higher plants); 中国生物多样性红色名录 脊椎动物 第一卷 哺乳动物 (Mammals); cf.
Colombia
: Libros Rojos, published by the Ministry of Environment and Sustainable Development
Czech Republic
: Červené seznamy, published by the ;
Denmark
: Den danske Rødliste, published by Aarhus University;
Finland
: Suomen lajien uhanalaisuus – Punainen kirja, jointly published by the Ministry of the Environment; Web Service of the Red List of Finnish Species, published on the
France
: La Liste rouge des espèces menacées en France; , published by the National Museum of Natural History
Germany
:
Greece
: Το Κόκκινο Βιβλίο των Απειλούμενων Ζώων της Ελλάδας, published by the Hellenic Zoological Society;
Iceland
: Válistar published by the ;
Italy
: Liste Rosse Nazionali, published by the Ministry of the Ecological Transition
Japan
: Ministry of the Environment Red List
Kazakhstan
:
Kyrgyzstan
: Кыргыз Республикасынын Кызыл китеби;
Latvia
:
Lithuania
:
Moldova
: Cartea roșie a Republicii Moldova, published by the Academy of Sciences of Moldova and Ministry of Environment;
Netherlands
:
New Zealand
: New Zealand Threat Classification System, published by the Department of Conservation
Nicaragua
: Lista Roja, Especies en Alto Riesgo
Norway
: Norsk rødliste for arter, published by Artsdatabanken;
Philippines
: National List of Threatened Fauna, maintained by the Department of Environment and Natural Resources
Poland
: Polska Czerwona Księga Zwierząt; Polska Czerwona Księga Roślin;
Russia
: Red Data Book of the Russian Federation; also by Federal subject — Sakhalin Oblast: Красная Книга Сахалинской области: Животные / Растения и грибы; Category:Красные книги по субъектам Российской Федерации
South Africa
: Red List of South African Plants, published by the South African National Biodiversity Institute.
South Korea
: 한국의 멸종위기 야생동·식물 적색자료집, published by the Ministry of Environment and (Red Data Book 1 = Birds 조류, 2 = Amphibians and Reptiles 양서류·파충류, 3 = Fish 어류, 4 = Mammals 포유동물, 5 = Vascular Plants 관속식물);
Spain
: Libro rojo de los vertebrados de España, Atlas y libro rojo de la flora vascular amenazada de España, published by the Ministry of Environment
Sri Lanka
: The National Red List 2012 of Sri Lanka, published by the Ministry of Environment
Sweden
: Rödlistade arter i Sverige, published by the Swedish University of Agricultural Sciences (SLU Artdatabanken)
Switzerland
: Rote Listen: Gefährdete Arten der Schweiz, published by the Federal Office for the Environment; cf.
Taiwan
: 紅皮書名錄, published by the and Forestry Bureau; (Red List 1 = birds 臺灣鳥類紅皮書名錄, 2 = terrestrial reptiles 臺灣陸域爬行類紅皮書名錄, 3 = amphibians 臺灣兩棲類紅皮書名錄, 4 = freshwater fishes 臺灣淡水魚類紅皮書名錄, 5 = terrestrial mammals 臺灣陸域哺乳類紅皮書名錄, 6 = vascular plants 臺灣維管束植物紅皮書名錄)
Tajikistan
:
Turkmenistan
: Türkmenistanyň Gyzyl Kitaby, published by the Ministry of Nature Protection;
Ukraine
: Red Data Book of Ukraine
United Kingdom
: Conservation designations for UK taxa, published by the JNCC
United States of America
: Federal Lists of Endangered and Threatened Wildlife and Plants, published by the United States Fish and Wildlife Service
Uzbekistan
: O'zbekiston Respublikasining Qizil kitobi;
Vietnam
: Vietnam's Red Data Book
See also
List of heritage registers
References
External links
IUCN Regional Guidelines
National Red List database
Red Lists | List of Red Lists | Biology | 1,299 |
60,613,037 | https://en.wikipedia.org/wiki/OctaDist | OctaDist is computer software for crystallography and inorganic chemistry program. It is mainly used for computing distortion parameters of coordination complex such as spin crossover complex (SCO), magnetic metal complex and metal–organic framework (MOF).
The program is developed and maintained in an international collaboration between the members of the Computational Chemistry Research Unit at Thammasat University, the Functional Materials & Nanotechnology CoE at Walailak University and the Switchable Molecules and Materials group at University of Bordeaux.
OctaDist is written entirely in Python binding to Tkinter graphical user interface toolkit. It is available for Windows, macOS, and Linux. It is free and open-source software distributed under a GNU General Public License (GPL) 3.0.
Standard abilities
The following are the main features of the latest version of OctaDist:
Structural distortion analysis
Determination of regular and irregular distorted octahedral molecular geometry
Octahedral distortion parameters
Volume of the octahedron
Tilting distortion parameter for perovskite complex
Molecular graphics
3D modelling of complex
Display of the eight faces of octahedron
Atomic orthogonal projection and projection plane
Twisting triangular faces
Molecular superposition (Overlay)
Other utilities
Scripting language
Surface area of the faces of octahedron
Jahn–Teller distortion parameters
Root-mean-square deviation of atomic positions
Capabilities
Simple and flexible processes of use
Cross-platform for both 32-bit and 64-bit systems
Graphical user interface (GUI)
Command-line interface (CLI)
User-friendly interactive scripting code
User-adjustable program setting
On top of huge and complicated complexes
Support for several outputs of computational chemistry software, including Gaussian, Q-Chem, ORCA, and NWChem
See also
List of quantum chemistry and solid-state physics software
References
External links
OctaDist official website
OctaDist at Github repository
OctaDist PyPI package
OctaDist at IUCr software archive
Computational chemistry software
Crystallography software
Free science software
2019 software | OctaDist | Chemistry,Materials_science | 407 |
78,811,704 | https://en.wikipedia.org/wiki/Wafer%20fabrication%20equipment | Wafer fabrication equipment is equipment that is used in the process of semiconductor fabrication to process raw semiconductor wafers into finished chips, such as integrated circuits.
Wafer fabrication equipment is meant to be installed in cleanrooms.
Types
Stepper
Burn-in oven
Market
Referred to respectively as the wafer fab equipment or wafer front end (equipment) market, both using the acronym WFE, the market is that of the manufacturers of the machines which in turn manufacture semiconductors. The apexresearch link in 2020 identified Applied Materials, ASML, KLA-Tencor, Lam Research, TEL and Dainippon Screen Manufacturing as market participants while the 2019 electronicsweekly.com report, citing The Information Network's president Robert Castellano, focused on the respective market shares commanded by the two leaders, Applied Materials and ASML.
See also
LCD manufacturing
FOUP
References
Semiconductor fabrication equipment
Semiconductor device fabrication | Wafer fabrication equipment | Materials_science,Engineering | 186 |
11,154,280 | https://en.wikipedia.org/wiki/History%20of%20the%20Jews%20in%20the%20Dominican%20Republic | The history of the Jews in the Dominican Republic goes back to the late 1400s, with the arrival of Sephardic Jews exiled from Spain and the Mediterranean area in 1492 and 1497. This was followed by new waves of migrants dating from the 1700s and again in the period before and during World War II, reaching a peak in the late 1930s and early 1940s, as Jewish refugees fled the conditions in Europe brought on by WWII.
History
The first Jews known to have reached the island of Hispaniola were Sephardi Jews who came from the Iberian Peninsula in the 1490s. The majority of them were fleeing from Spain, where conversion to Catholicism was being enforced.
Despite this, when the island was divided by the French and Spanish Empires in the 17th century, most Jews settled on the Spanish side which would later become the Dominican Republic. Eventually, Sephardim from other countries also arrived. Most of them hid their Jewish identities or were unaffiliated with Jewish tradition by that time. Among their descendants were Dominican President Francisco Henríquez y Carvajal and his issue Pedro Henríquez Ureña, Max Henríquez Ureña, and Camila Henríquez Ureña.
Before the Jews migrated and established the colony of Sosúa during WWII, there was an attempt to make a Jewish colony in the Dominican Republic in the late 19th century. This settlement was not as well documented as the one created in the 1940s. General Gregorio Luperón, who had served as President of the Dominican Republic and was living in exile in Paris in 1882, proposed the country as a refuge for Jews escaping pogroms in Russia. Luperón's motivations for proposing this plan seem to have stemmed from a combination of humanitarian concern and a desire to promote the economic development of the Dominican Republic. He believed that the Jewish refugees, with their skills and work ethic, could contribute to the prosperity of the country. Luperón initiated contact with several key figures and organizations in the Jewish world in order to circulate the idea. These figures included Alliance Israélite Universelle, The prominent Rothschild banking family, and the Jewish community in the United States, particularly in New York. While many Dominicans and Jews living in the Dominican Republic were already in favor of the idea, others opposed the plan. Others raised practical concerns about the plan, particularly the need for financial support, land allocation, and employment opportunities for potential settlers. It appears that a commission of Dominican landowners was formed to investigate the feasibility of the plan but that no concrete action was ultimately taken. While Luperón's plan for a Jewish colony in the Dominican Republic in the 1880s ultimately failed to materialize, it demonstrates the Dominican Republic's recurring role as a potential haven for Jewish refugees during times of crisis.
The Dominican Republic was the only sovereign country willing to accept mass Jewish immigration immediately prior and during World War II, the only alternative being the Shanghai International Settlement. The United States government had attempted to also set up a Jewish colony in Alaska in order to populate the area. However, what would become known as The Alaska Plan, was effectively buried due to a lack of support and opposition from antisemitic and nativist groups. In turn, support for the Jews fell almost solely on the Dominican Republic. At the Évian Conference, convened to address the Jewish refugee crisis, the Dominican Republic, under the rule of dictator Rafael Trujillo, offered to accept 100,000 Jewish refugees. However, It is estimated that 5,000 visas were actually issued, and the vast majority of the recipients did not reach the country because of how hard it was to get out of occupied Europe. Trujillo then offered his personal estate in Sosúa to the Dominican Republic Settlement Association (DORSA), established by the American Jewish Joint Distribution Committee (JDC) to manage the resettlement project. In return for his land, Trujillo received $100,000 in DORSA stock. By February of 1940, DORSA had managed to get congressional approval for the settlement in Sosua and the plan began to move forward. By Spring of that year, the colony began receiving its first settlers. About 700 European Jews of Ashkenazi Jewish descent reached the settlement where each family received of land, 10 cows (plus 2 additional cows per child), a mule and a horse, and a US$10,000 loan (about dollars at prices) at 1% interest. The colonists were expected to engage in communal agriculture, sharing work and profits equally. Dairying and poultry raising were also intended as complementary activities. However, crop-based agriculture proved largely unsuccessful due to poor soil, unpredictable rainfall, and limited market access.Due to the challenges of communal agriculture, the colony transitioned to a capitalist model by 1945, with individual families receiving their own farms. The only exception to this individualistic approach was the dairy and meat factories, which were run as cooperatives with profits divided according to investment. Those who did not travel to Sosúa usually settled in the capital, Santo Domingo. In 1943 the number of known Jews in the Dominican Republic peaked at 1000.
At the conclusion of WWII, The Jewish population in Sosúa gradually declined as residents relocated, mostly to the United States. As a portion of the Jewish population left, Dominican residents began to move in Sosúa. Throughout the majority of the 20th century, Sosúa existed as a mixed community of Jewish and Dominican residents, with the Jewish population aging and shrinking. The Dominican influence, both economic and cultural, becomes increasingly prominent. This peaked in 1980 when Sosúa's Jewish community experienced a deep decline due to emigration during the touristic boom of Sosúa when most Jews sold their land to developers.
Community
The current population of known Jews in the Dominican Republic is close to 3,000, with the majority living in the capital, Santo Domingo, and others residing in Sosúa. However, while the Jewish community in Sosúa still exists, it has shrunk considerably. Many of the original settlers have passed away or emigrated, and their children often choose not to return. The community retains some of its unique character, with a mix of languages and cultural traditions, but the future of the Jewish community in Sosúa remains uncertain.Since Jews mixed with those already living in the Dominican Republic, the exact number of Dominicans with Jewish ancestry isn't known. In spite of the Jews intermarriage with the Dominican people already living there, some spouses have formalized their Judaism through conversions and participate in Jewish communal life while other Sephardic Jews converted to Catholicism, still maintaining their Sephardic culture. Some Dominican Jews have also made aliyah to Israel. There are three synagogues and one Sephardic Jewish Educational Center. One is the Centro Israelita de República Dominicana in Santo Domingo, another is a Chabad outreach center also in Santo Domingo, and another is in the country's first established community in Sosúa. Beth Midrash Eleazar , the Sephardic Educational Center, caters to those Jews who are descendants of the Sephardic Jews that migrated to Hispaniola in colonial times and later. In addition, they also provide kosher meat in the Beth Yoseph style, and supervise a small-scale kosher bakery. An "afterschool" at the Centro Israelita is active on a weekly basis and a chapter of the International Council of Jewish Women is also active. The Chabad outreach center focuses on assisting the local Jewish population reconnect with their Jewish roots and (because Chabad is of the Chassidic Jewish tradition) it is a source for traditional Judaism in the Dominican Republic. In Sosua, there is a small Jewish Museum next to the synagogue. On the High Holidays, the Sosúa community hires a cantor from abroad who comes to lead services.
Research
A great deal of research on the subject of Dominican Jewry was done by Rabbi Henry Zvi Ucko who had been a writer and teacher in Germany until political conditions and growing anti-Semitism forced him to emigrate. His travels eventually took him to the Dominican Republic, where he organized a congregation in Santo Domingo (Ciudad Trujillo) and began researching the history of Jews in the country. His research covered much of the history of the Sephardic Jews there and documented the assimilation that the population went through (and was going through) during his time. Included in his research is correspondence with Haim Horacio López Penha, a Dominican Jewish writer, who encouraged Ucko to write a history of the Jews in the Dominican Republic. More recently, the publication of the book "Once Jews" has made easily available information on many early Jewish settlers in the Dominican Republic. Scholars such as the historian of the town of Baní, Manuel Valera, as well as Dr. Yehonatan Demota, continue the study of Dominican Sephardic and converso ancestry, and the question of the Dominican anusim.
References
External links
History of Sosua, Dominican Republic
More about the Sosua Community
Tropical Zion: General Trujillo, FDR, and the Jews of Sosúa by Allen Wells
Sosua Virtual Museum
Jews
Dominican Republic
Dominican Republic
Jews
Dominican Republic
Dominican Republic | History of the Jews in the Dominican Republic | Biology | 1,879 |
13,971,206 | https://en.wikipedia.org/wiki/Argiotoxin | Argiotoxins represent a class of polyamine toxins isolated from the orb-weaver spider (Araneus gemma and Argiope lobata).
The orb-weaver spiders, also known as araneids; belong to the Araneidae spider family. This type of spider is found in almost every area of the world.
Classification
Argiotoxin can be classified, according to the 1980s classification of spider venoms, as a toxin of the acylpolyamines family, which contains more than 100 different chemical structures of closely related toxins. Acylpolyamines are neurotoxic compounds that are found only in the venom glands of spiders at a picomolar level.
Argiotoxins are classified into three different categories according to its chromophore's nature: the argiopine type, the argiopinine type and the pseudoargiopinine type.
Argiopine: contains 2,4-dihydroxyphenylacetic acid. It is also named Arg-636.
Argiopinines: (4-hydroxyindol-3-yl) acetic acid is carried as the chromophore. These molecules are: Arg-630, Arg-658, Arg-659, Arg-744, Arg-759.
Pseudoargiopinines: They contain a (indol-3-yl) acetic acid. This group is composed of: Arg-373, Arg-728, Arg-743.
Biochemical structure
It is a low-molecular-weight neurotoxin which has highly functional polar groups: free phenolic OH and amine and guanidine residues.
It also possesses arginine (free NH2) connected to a -NH (CH)3 NH (C ~) 3NH (CH) 5-NH- one through a peptide bond polyamine. The polyamine is connected to the asparagine's α-carboxyl group. The amino group of this aminoacid is linked to 2,4-dihydroxyphenyl acetic acid.
Its structure was established using spectroscopy 1H, 13C-RMN, mass spectrometry, and elemental aminoacid analysis.
A complete synthesis strategy of argiotoxin and derivatives was developed in order to make biological tests in different living beings.
A noted type of argiotoxin, the Arg-636, which molecular formula is C29H52N10O6 [3], has a molecular weight of 636.78658 g/mol. It has a formal charge of 0. Its IUPAC name is: (2S) - N- { 5 - [ 3 - ( 3 - [ [ (2S)-2-amino-5-(diaminomethylideneamino) pentanoyl ] amino ] propylamino ) propylamino ] pentyl } -2- { [ 2 - (2,4-dihydroxyphenyl) acetyl ] amino } butanediamide
Effects and properties
The effects of argiotoxin, when it enters an organism by a spider bite, are harmless to humans, although in certain cases the bite of argiotoxin spiders can produce mild swelling and itching. Argiotoxin antagonizes the actions of the neurotransmitter glutamate, blocks the functioning of ion channel and affects the synaptic transmission of preys. These toxins, like all the other low-molecular-weight toxins, have a huge potential to be used in neurochemical studies to develop novel drugs of neurotherapeutic applications.
Mechanism of action of argiotoxins
This spider's venom shows varied action mechanisms that affect the different parts of the nervous impulse transmission chain. As mentioned above, Argiotoxins are polyamine toxins. This biomolecular group can effectively inhibit certain ligand-gated ion channels in the central nervous system of mammals and the insects' glutamic receptor (it has been characterized as an opposite of homomeric and heteromeric glutamate-activated receptor channels ). It has been seen that it can also inhibit the following receptors: AMPA, NMDA (argiotoxin has higher potency at NMDA receptors), kainate, and nicotine acetylcholine receptors. It is thought that polyamine toxins' inhibition is both use and voltage dependent. What is more, they bind within the pore of the open channels they inhibit.
A lot of attention is drawn to the pharmacological uses of polyamine toxins. They are highly valuable due to their high affinity for ionotropic glutamate receptors, important drug targets for psychiatric disorders. It has not been developed yet, although it is thought that it could be a great procedure in neuroprotection and in the treatment of Alzheimer's disease.
Argiotoxin could even be used as a tool for analyzing the subunit composition of AMPA receptors in native membranes.
Argiotoxin-636
The most relevant example for the strategies mentioned above is the Argiotoxin-636. This is a polyamine toxin isolated from the Argiope lobata's venom. However, there are still some difficulties, as ArgTX-636 cannot distinguish the different subtypes of ionotropic glutamate receptors.
This same toxin is demonstrated to be a good regulator for melanogenesis without cytotoxicity. That's why ArgTX-636 is playing a leading role in the research of cosmetic products against hyper pigmentation.
ArgTX-636 can also work as an analgesic due to some peripheral actions. Thanks to its action as inhibitor on gtutamate-activated channels it could work as an anti convulsant.
Experiments with argiotoxins
Argiotoxins studies have been particularly made to discover the relation between inhibition, receptors, and ionic channels. Researchers have specifically pursued the blocking of receptors on invertebrates, rather than on vertebrates.
Referring to invertebrates, Planorbarius corneus is a mollusc involved in one of the many ionic experiments. To begin with, neurons of molluscan pedal ganglia were isolated and transferred to a special chamber with saline solution and regulated temperature. Then, the observation was based on routine voltage clamp technique. Electrical measurements were obtained from the evaluation of neurons response to various substances (argiopines).
In addition to that, crayfish, a freshwater crustacean, has followed a similar protocol to this study. In this case, the analysis was made of the stomach muscles and using the patch clamp technique. The research findings were obtained taking into account the bursts of openings of excitatory channels.
Other experiments use spectroscopy in order to analyse and differentiate these molecules. HPLC, mass spectrometry, UV data and amino acid analysis are the elements that allow identifying diverse argiotoxins due to their spectrum. Argiope lobata toxins (Arg 636, Arg 630, Arg 658, Arg 744, Arg 759, Arg 373, Arg 728, Arg 723, ...) show a close similarity in their structures; the subtle differences between them are chemical points, such as N-methyl groups, molecular masses or lysine residues that are determined in a certain position in their structure.
See also
Argiope lobata
Araneus gemma
Delucemine
Neurotoxin
References
External links
Spider toxins
Amides
Guanidines
Phenols
Polyamines
Invertebrate toxins | Argiotoxin | Chemistry | 1,616 |
14,818,313 | https://en.wikipedia.org/wiki/Oncomodulin%202 | Oncomodulin 2, also known as OCM2, is a human gene that is similar to oncomodulin.
Oncomodulin is a high-affinity calcium ion-binding protein. It belongs to the superfamily of calmodulin proteins, also known as the EF-hand proteins. Oncomodulin 2 is an oncodevelopmental protein found in early embryonic cells in the placenta and also in tumors.
References
Further reading | Oncomodulin 2 | Chemistry | 95 |
50,797,595 | https://en.wikipedia.org/wiki/Form%20factor%20%28design%29 | Form factor is a hardware design aspect that defines and prescribes the size, shape, and other physical specifications of components, particularly in electronics. A form factor may represent a broad class of similarly sized components, or it may prescribe a specific standard. It may also define an entire system, as in a computer form factor.
Evolution and standardization
As electronic hardware has become smaller following Moore's law and related patterns, ever-smaller form factors have become feasible. Specific technological advances, such as PCI Express, have had a significant design impact, though form factors have historically evolved slower than individual components. Standardization of form factors is vital for hardware compatibility between different manufacturers.
Trade-offs
Smaller form factors may offer more efficient use of limited space, greater flexibility in the placement of components within a larger assembly, reduced use of material, and greater ease of transportation and use. However, smaller form factors typically incur greater costs in the design, manufacturing, and maintenance phases of the engineering lifecycle, and do not allow the same expansion options as larger form factors. In particular, the design of smaller form-factor computers and network equipment must entail careful consideration of cooling. End-user maintenance and repair of small form-factor electronic devices such as mobile phones is often not possible, and may be discouraged by warranty voiding clauses; such devices require professional servicing—or simply replacement—when they fail.
Examples
Computer form factors comprise a number of specific industry standards for motherboards, specifying dimensions, power supplies, placement of mounting holes and ports, and other parameters. Other types of form factors for computers include:
Small form factor (SFF), a more loosely defined set of standards that may refer to both motherboards and computer cases. SFF devices include mini-towers and home theater PCs.
Pizza box form factor, a wide, flat case form factor used for computers and network switches; often sized for installation in a 19-inch rack.
All-in-one PC
"Lunchbox" portable computer
Components
Hard disk drive form factors, the physical dimensions of a computer hard drive
Hard disk enclosure form factor, the physical dimensions of a computer hard drive enclosure
Motherboard form factor, the physical dimensions of a computer motherboard
Memory module form factors
Mobile form factors
Laptop or notebook, a form of portable computer with a clamshell design.
Subnotebook, ultra-mobile PC, netbook, and tablet computer, various form factors for devices that are smaller and often cheaper than a typical notebook.
Mobile phone, including a wide range of sizes and layouts. Broad categories of form factors include bars, flip phones, and sliders, with many subtypes and variations. Also include phablets (small tablets) and industrial handheld devices.
Stick PC, a single-board computer in a small elongated casing resembling a stick
See also
Computer hardware
Electronic packaging
Packaging engineering
List of computer size categories
List of integrated circuit package dimensions
Notes
References
Design
Electronic design
Industrial design
Packaging
Broad-concept articles | Form factor (design) | Engineering | 601 |
5,362,319 | https://en.wikipedia.org/wiki/Information%20diving | Information diving is the practice of recovering technical data, sometimes confidential or secret, from discarded material. In recent times, this has chiefly been from data storage elements in discarded computers, most notably recoverable data remaining on hard drives. Those in charge of discarding computers usually neglect to erase the hard drive. It is often in such circumstances for an information diver to copy installed software (e.g., word processors, operating systems, computer games, etc.). Other data may also be available, such as credit card information that was stored on the machine. Companies claim to be especially careful with customer data, but the number of data breaches by any type of entity (e.g., education, health care, insurance, government, ...) suggest otherwise. In the UK, information diving has been referred to as "binology".
Today, files, letters, memos, photographs, IDs, passwords, credit cards, and more can be found in dumpsters. Many people do not consider that sensitive information on items they discarded may be recovered. Such information, when recovered, is sometimes usable for fraudulent purposes (see also "identity theft" and physical information security). This method of dumpster diving is also sometimes used by attorneys or their agents when seeking to enforce court-ordered money judgments: the judgment debtor's trash may contain information about assets that can then be more-readily located for levying.
Supposedly, information diving was more common in the 1980s due to lax security; when businesses became aware of the need for increased security in the early 1990s, sensitive documents were shredded before being placed in dumpsters. There is still considerable Internet activity on the subject of dumpster diving, so it is unlikely to have stopped with the widespread introduction of document shredding. Security mythology has it that curious hackers or malicious crackers commonly use this technique.
Cases
Printed manuals
In earlier times, the available discarded data included printed manuals and design records. In a famous case, a student, Jerry Schneider, discovered some discarded manuals for a telephone system ordering/shipping system and was able to build a business selling 'surplus' gear ordered from the telephone company as though it was for an internal company department.
Discarded computers
Two MIT students purchased a large number of obsolete computers at yard sales, and they were able to obtain information such as credit card information and tax return data. They published a paper, Remembrance of Things Past, documenting their discoveries.
Dumpster diving
Dumpster diving is commonly practiced by "watchdog" organizations seeking information on groups they are investigating. The Trinity Foundation successfully used this technique to report on the activities of televangelist Robert Tilton and was also able to obtain information on Benny Hinn.
See also
Dumpster diving
E-waste
Credit card fraud
Copyright infringement of software
Benjamin Pell
References
Security
Carding (fraud)
Data security | Information diving | Engineering | 582 |
14,488,084 | https://en.wikipedia.org/wiki/Eltrombopag | Eltrombopag, sold under the brand name Promacta among others, is a medication used to treat thrombocytopenia (abnormally low platelet counts) and severe aplastic anemia. Eltrombopag is sold under the brand name Revolade outside the US and is marketed by Novartis. It is a thrombopoietin receptor agonist. It is taken by mouth.
Eltrombopag was discovered as a result of research collaboration between GlaxoSmithKline and Ligand Pharmaceuticals and is transferred to Novartis Pharmaceuticals.
Medical uses
Eltrombopag was approved by the US Food and Drug Administration (FDA) in November 2008, for the treatment of thrombocytopenia in people with chronic immune (idiopathic) thrombocytopenic purpura who have had an insufficient response to corticosteroids, immunoglobulin therapy, or splenectomy.
In August 2015, the FDA approved eltrombopag (Promacta for oral suspension) for the treatment of thrombocytopenia in children one year of age and older with idiopathic thrombocytopenia who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy.
Development
In preclinical studies, the compound was shown to interact selectively with the thrombopoietin receptor, leading to activation of the JAK-STAT signaling pathway and increased proliferation and differentiation of megakaryocytes. Animal studies confirmed that it increased platelet counts. In 73 healthy volunteers, higher doses of eltrombopag caused larger increases in the number of circulating platelets without tolerability problems.
Clinical trials
Eltrombopag has been shown to be effective in two major clinical syndromes: idiopathic thrombocytopenic purpura (ITP) and cirrhosis due to hepatitis C (in which low platelet counts may be a contraindication for interferon treatment).
After six weeks of therapy in a phase III trial, eltrombopag 50 mg/day was associated with a significantly higher response rate than placebo in adult patients with chronic idiopathic thrombocytopenic purpura (ITP).
History
Eltrombopag received breakthrough therapy designation from the US Food and Drug Administration (FDA) in February 2014, for people with aplastic anemia for which immunosuppression has not been successful. In 2017, the NIH made Eltrombopag a standard of care in aplastic anemia.
Society and culture
Legal status
In October 2024, the Committee for Medicinal Products for Human Use of the European Medicines Agency adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Eltrombopag Viatris, intended for the treatment of people with primary immune thrombocytopenia (ITP) and thrombocytopenia associated with chronic hepatitis C. The applicant for this medicinal product is Viatris Limited. Eltrombopag Viatris was authorized in December 2024.
Research
It has been shown to produce a trilineage hematopoiesis in some people with aplastic anemia, resulting in increased platelet counts, along with red and white blood cell counts.
References
External links
Biphenyls
Carboxylic acids
Drugs acting on the blood and blood forming organs
Drugs developed by GSK plc
Hydrazines
Drugs developed by Novartis
Orphan drugs
Thrombopoietin receptor agonists | Eltrombopag | Chemistry | 747 |
19,860,367 | https://en.wikipedia.org/wiki/Environmental%20adult%20education | Environmental adult education is a "hybrid outgrowth of the environmental movement and adult education, combining an ecological orientation with a learning paradigm to provide a vigorous educational approach to environmental concerns." It refers to efforts in teaching environmental issues and how individuals and businesses can manage or change their lifestyles and their ecosystems in order to achieve sustainable existence. The overarching goal of this field of study is to educate global citizens in order for them to gain sustainable lives within their respective societies. The content could also include ecological justice, integrating social concerns such as poverty, race, gender, and sexual orientation, among others. This relationship is demonstrated in the impact of the excesses of global capitalism and its insatiable need for resources on people such as the polarization of power and wealth.
History
Environmental adult education is a relatively new field of study and practice. Using a community-based method, educators listen and respect the input of learners and all participants are considered essential.
Although for more than a century, environmental and conservation organizations taught adults environmental education with very little structure, it has actually evolved during the last thirty years.
The United States was one of the first countries to officially recognize environmental education. During a joint House–Senate session in 1968, Congress acknowledged the importance of environmental education, and in 1970 passed the Environmental Education Act, which established the Office of Environmental Education. In 1992, this framework began to emerge in Asia and Latin America, where it is considered a stream of adult education and sometimes referred to as environmental popular education. The United Nations, for its part, began integrating the concept of environmental sustainability to the Education for All initiative, which is a set of UN policies with a goal of meeting learning needs of all people, as well as the Millennium Development Goals (MDGs). Specifically, the UN-organized Earth Summit in 1992, prompted the International Council for Adult Education to develop the Learning for Environmental Action Programme (LEAP) which took the initiative of facilitating the dialogue that connect environmental issues and adult learning.
Earlier environmental education initiatives
According to UNESCO, in 1968 it organized the first intergovernmental conference aimed at reconciling the environment and development, now known as sustainable development. In the following years, UNESCO and the United Nations Environment Program (UNEP) initiated three major declarations that defined environmental education. Those included:
1972: Stockholm Declaration. This document included seven proclamations and 26 principles "to inspire and guide the peoples of the world in the preservation and enhancement of the human environment."
1975: Belgrade Charter. The product of the International Workshop on Environmental Education, this charter built upon the Stockholm Declaration by adding goals, objectives and principles for environmental education programs.
1977: Tbilisi Declaration. This document updated and clarified the Stockholm Declaration and the Belgrade Charter by including new goals, objectives, characteristics, and guiding principles of environmental education.
Methods
Educators in this field of study consider environmental problems with a holistic approach that combines social, political and environmental concerns into community dilemmas.
Participatory methods allow learners to make connections between social issues and environmental problems. This connection allows adult learners to understand the core causes of major environmental issues and the resulting social inequalities. This method also allows educators to stress the importance of instilling environmental awareness so that learners do not forget their relationship with the natural world.
To summarize the methods of adult environmental education training, environmental adult educators strive to instil learners with:
a knowledge of environmental problems and their causes,
the skills to engage in social activism to combat those problems,
the attitude of respect and connection to the natural world, and
a desire to change current practices to protect the Earth.
Environmental adult education generally takes place in a nonformal education setting. This means that the organized learning can take place in many forms including vocational education, literacy education and on the job training. There are, however, examples of formal learning such as the degree programs and courses in higher education. It could also be a combination of these methods of environmental educational program delivery as demonstrated in the case of El Salvador's National Environmental Education Strategy, which covered all aspect of education via a private-public partnership. The government - through its Ministry of Education - integrated environmental education in schools, including tertiary education institutions, while partners such as media outfits deliver meaningful environmental concepts to targeted audiences and the general public.
Programs and organizations
Programs and organizations that encourage adult environmental education include:
Conservation education and governmental agencies such as the United States Forest Service and the Environmental Protection Agency (EPA) were established to educate adults in broad areas of the environment.
The Nature Conservancy, originally the Ecological Society of America, was formed in 1915 with the missions of supporting ecologists and preserving natural ecosystems.
The 4-H Organization was also established to reach adults by educating youth in areas of new agricultural technology and environmental awareness.
The Peace Corps, established in 1961, has worked to incorporate adult environmental education and conservation practices into its international programming. Volunteers assist in:
Project WILD is a conservation and environmental education program for educators of students in kindergarten through high school. Project WILD addresses the need for human beings to develop as responsible citizens of the planet. It is based on the belief that young adults and educators have an interest in learning about the natural world.
Project Learning Tree, a program of the American Forest Foundation, is a multi-disciplinary environmental education program for educators and students in PreK–Grade 12.
Gobar Times a monthly environmental education magazine for the young adult.
References
Notes
Bibliography
American Geological Institute (2000). Update on the National Environmental Education Act of 1990. Retrieved September 27, 2008 from the American Geological Institute Web site: http://www.agiweb.org/gap/legis106/neea106.html
Environmental Education (2008). The Modern Impetus for EE: The Tbilisi Declaration (1977). Retrieved September 27, 2008, from the Global Development Research Center Web site: http://www.gdrc.org/uem/ee/1-4.html
Haugen, C.S. (2006). Environmental Adult education Theory and Adult Learning Principles: Implications for Training. M.A. thesis, American University, in Proquest Digital Dissertations
Hill, L.H. & Johnston, J.D. (2003). Adult education and humanity's relationship with nature reflected in language, metaphor and spirituality: A call to action. New directions for adult and continuing education, Fall 2003 (99), 17–26
Parker, J & Towner, E. (1993). Editorial: Learning for the future. Adults learning, 4 (8) 208–209
Sumner, J (2003). Environmental adult education and community sustainability. New directions for adult and continuing education, Fall (99), 39–45.
United Nations Environment Programme (2008). Declaration of the United Nations Conference on the Human Environment. Retrieved September 27, 2008, from United Nations Environment Programme Web site: http://webarchive.loc.gov/all/20150314024203/http%3A//www.unep.org/Documents.Multilingual/Default.asp?documentid%3D97%26articleid%3D1503
United Nations Environment Programme (2008). The Belgrade Charter adopted at the International Workshop on Environmental Education in 1975. Retrieved September 27, 2008, from United Nations Environment Programme Web site: https://web.archive.org/web/20090226013849/http://portal.unesco.org/education/en/ev.php-URL_ID%3D33037%26URL_DO%3DDO_TOPIC%26URL_SECTION%3D201.html
External links
United Nations Educational, Scientific and Cultural Organization
The Peace Corps
The 4-H Organization: History
U.S. Environmental Protection Agency: History
U.S. Forestry Service: History
The Nature Conservancy
Project WILD
Project Learning Tree
Adult Learners and the Environment in Last Century: An Historical Analysis of Environmental Adult Education
Challenges for Environmental Education: Issues and Ideas for the 21st Century
Child-orientated environmental education influences adult knowledge and household behaviour
Alternative education
Outdoor education | Environmental adult education | Environmental_science | 1,662 |
66,826,202 | https://en.wikipedia.org/wiki/Russula%20galbana | Russula galbana is a fungus in the family, Russulaceae, found in leaf litter in open forests of Allocasuarina littoralis and Eucalyptus tereticornis in Queensland.
It was first described in 2007 by Teresa Lebel and Jennifer Tonkin.
References
galbana
Taxa named by Teresa Lebel
Fungus species | Russula galbana | Biology | 67 |
77,196,595 | https://en.wikipedia.org/wiki/Bolitoglossa%20aurae | Bolitoglossa aurae, commonly known as Aura's golden salamander, is a lungless salamander found in the rainforests of Cordillera de Talamanca in Costa Rica. This species is part of the Bolitoglossa genus, commonly known as mushroom-tongued salamanders.
Description
Bolitoglossa aurae has a light yellow color with a dark brown dorsal stripe running down the head through the body and a pair of thin dark brown lateral stripes running from behind the eyes to the tail. The species has long prehensile tails relative to other mushroom-tongued salamanders. Its tail is 57.9% of its total length.
Habitat and dispersal
Aura's golden salamander is believed to be an endemic species of Costa Rica but its range is not currently known. The mid-elevation slopes of northeastern Cordillera de Talamanca are the only known environment inhabited by Bolitoglossa aurae. Aura's golden salamander inhabits cloud forests.
Behavior
Bolitoglossa aurae is nocturnal and burrows during the day.
References
aurae
Amphibians described in 2016
Nocturnal animals
Endemic fauna of Costa Rica | Bolitoglossa aurae | Biology | 246 |
4,601,187 | https://en.wikipedia.org/wiki/Autocorrelation%20technique | The autocorrelation technique is a method for estimating the dominating frequency in a complex signal, as well as its variance. Specifically, it calculates the first two moments of the power spectrum, namely the mean and variance. It is also known as the pulse-pair algorithm in radar theory.
The algorithm is both computationally faster and significantly more accurate compared to the Fourier transform, since the resolution is not limited by the number of samples used.
Derivation
The autocorrelation of lag 1 can be expressed using the inverse Fourier transform of the power spectrum :
If we model the power spectrum as a single frequency , this becomes:
where it is apparent that the phase of equals the signal frequency.
Implementation
The mean frequency is calculated based on the autocorrelation with lag one, evaluated over a signal consisting of N samples:
The spectral variance is calculated as follows:
Applications
Estimation of blood velocity and turbulence in color flow imaging used in medical ultrasonography.
Estimation of target velocity in pulse-doppler radar
External links
A covariance approach to spectral moment estimation, Miller et al., IEEE Transactions on Information Theory.
Doppler Radar Meteorological Observations Doppler Radar Theory. Autocorrelation technique described on p.2-11
Real-Time Two-Dimensional Blood Flow Imaging Using an Autocorrelation Technique, by Chihiro Kasai, Koroku Namekawa, Akira Koyano, and Ryozo Omoto, IEEE Transactions on Sonics and Ultrasonics, Vol. SU-32, No.3, May 1985.
Radar theory
Signal processing
Autocorrelation | Autocorrelation technique | Technology,Engineering | 325 |
196,567 | https://en.wikipedia.org/wiki/Coda%20%28music%29 | In music, a coda (; ; plural ) is a passage that brings a piece (or a movement) to an end. It may be as simple as a few measures, or as complex as an entire section.
In classical music
The presence of a coda as a structural element in a movement is especially clear in works written in particular musical forms. Codas were commonly used in both sonata form and variation movements during the Classical era. In a sonata form movement, the recapitulation section will, in general, follow the exposition in its thematic content, while adhering to the home key. The recapitulation often ends with a passage that sounds like a termination, paralleling the music that ended the exposition; thus, any music coming after this termination will be perceived as extra material, i.e., as a coda. In works in variation form, the coda occurs following the last variation and will be very noticeable as the first music not based on the theme.
One of the ways that Beethoven extended and intensified Classical practice was to expand the coda sections, producing a final section sometimes of equal musical weight to the foregoing exposition, development, and recapitulation sections and completing the musical argument. For one famous example, see the finale of Symphony No. 8 (Beethoven).
Musical purpose
Charles Burkhart suggests that the reason codas are common, even necessary, is that, in the climax of the main body of a piece, a "particularly effortful passage", often an expanded phrase, is often created by "working an idea through to its structural conclusions" and that, after all this momentum is created, a coda is required to "look back" on the main body, allow listeners to "take it all in", and "create a sense of balance."
Codetta
Codetta (Italian for "little tail", the diminutive form) has a similar purpose to the coda, but on a smaller scale, concluding a section of a work instead of the work as a whole. A typical codetta concludes the exposition and recapitulation sections of a work in sonata form, following the second (modulated) theme, or the closing theme (if there is one). Thus, in the exposition, it usually appears in the secondary key, but, in the recapitulation, in the primary key. The codetta ordinarily closes with a perfect cadence in the appropriate key, confirming the tonality. If the exposition is repeated, the codetta is likewise repeated. Sometimes it has its ending slightly changed, depending on whether it leads back to the exposition or into the development sections.
History
Cauda, a Latin word meaning "tail", "edge" or "trail" is the root of coda and is used in the study of conductus of the 12th and 13th centuries. The cauda was a long melisma on one of the last syllables of the text, repeated in each strophe. Conducti were traditionally divided into two groups, conductus cum cauda and conductus sine cauda (Latin: "conductus with cauda", "conductus without cauda"), based on the presence of the melisma. Thus, the cauda provided a conclusionary role, similar to the modern coda.
In popular music
Many songs in rock and other genres of popular music have sections identifiable as codas. A coda in these genres is sometimes referred to as an "outro", while in jazz, modern church music and barbershop arranging it is commonly called a "tag". One of the most famous codas is found in the 1968 single "Hey Jude" by the Beatles. The coda lasted nearly four minutes, making the song's full length at just over the seven-minute mark.
In music notation
In music notation, the coda symbol, which resembles a set of crosshairs, is used as a navigation marker, similar to the dal segno sign. It is used where the exit from a repeated section is within that section rather than at the end. The instruction "To Coda" indicates that, upon reaching that point during the final repetition, the performer is to jump immediately to the separate section headed with the coda symbol. The symbol can be used to provide a special ending for the final verse of a song.
The coda sign is encoded in the Musical Symbols block of Unicode as U+1D10C MUSICAL SYMBOL CODA: 𝄌
See also
Coda (ballet)
Da capo
Epilogue
Fade (audio engineering)
Repeat sign
Transition (music)
Notes
References
External links
Auxiliary members
Italian words and phrases
Musical notation
Formal sections in music analysis
Musical terminology | Coda (music) | Technology | 959 |
40,084,006 | https://en.wikipedia.org/wiki/Smart%20lock | A smart lock is an electromechanical lock that is designed to perform locking and unlocking operations on a door when it receives a prompt via an electronic keypad, biometric sensor, access card, Bluetooth, or Wi-FI from a registered mobile device. These locks are called smart locks because they use advanced technology and Internet communication to enable easier access for users and enhanced security from intruders. The main components of the smart lock include the physical lock, the key (which can be electronic, digitally encrypted, or a virtual key to provide keyless entry), a secure Bluetooth or Wi-Fi connection, and a management mobile app. Smart locks may also monitor access and send alerts in response to the different events it monitors, as well as other critical events related to the status of the device. Smart locks can be considered part of a smart home.
Most smart locks are installed on mechanical locks (simple types of locks, including deadbolts) and they physically upgrade the ordinary lock. Recently, smart locking controllers have also appeared at the market.
Smart locks, like the traditional locks, need two main parts to work: the lock and the key. In the case of these electronic locks, the key is not a physical key but a smartphone or a special key fob or keycard configured explicitly for this purpose which wirelessly performs the authentication needed to automatically unlock the door
Smart locks allow users to grant access to a third party by means of a virtual key. This key can be sent to the recipient smartphone over standard messaging protocols such as e-mail or SMS, or via a dedicated application. Once this key is received, the recipient will be able to unlock the smart lock using their mobile device during the timeframe previously specified by the sender.
Certain smart locks include a built-in Wi-Fi connection that allows for monitoring features such as access notifications or cameras to show the person requesting access. Some smart locks work with a smart doorbell to allow the user to see who and when someone is at a door. Many smart locks now also feature biometric features, such as fingerprint sensors. Biometrics are becoming increasingly popular because they offer more security than passwords alone. This is because they use unique physical characteristics rather than stored information.
Smart locks may use Bluetooth Low Energy and SSL to communicate, encrypting communications using 128/256-bit AES.
Industry smart lock
Industrial smart locks (passive electronic lock) are a branch of the smart lock field. They are an iterative product of mechanical locks like smart locks. However, the application areas of industrial smart locks are not smart homes, but fields that have extremely high requirements for key management, such as communications, power utilities, water utilities, public safety, transportation, data centers, etc.
Industry smart locks mainly have three components: locks and keys, and management systems. Similarly, the key is no longer a physical key, but a special electronic key. When unlocking, the unlocking authority needs to be assigned before. Through the management system, the administrator needs to set the user, unlock date and time period for the key. Whenever the user unlocks or locks the lock, the unlock record will be saved in the key. The unlocking record can be tracked through the management software.
At the same time, industry smart locks can also remotely assign permissions through a mobile app.
Security
Due to the inherent complexity of digital and wireless technologies, it can be difficult for the end user to confirm or refute the security claims of various product offerings on the market. The devices may also gather personal information; representations by the vendors involved concerning the care and handling of this information is also difficult for the end user to verify.
See also
Door loop, a method for providing electric cabling to a door
References
External links
Smart devices
Locks (security device) | Smart lock | Technology | 778 |
37,455,368 | https://en.wikipedia.org/wiki/Internal%20measurement | In quantum mechanics, internal measurement refers to the measurement of a quantum system by an observer (referred to as an internal observer or endo-observer).
A quantum measurement represents the action of a measuring device on a quantum system. When the measuring device is a part of the measured quantum system, the measurement proceeds internally in relation to the whole system.
Internal measurement theory was first introduced by Koichiro Matsuno and developed by Yukio-Pegio Gunji. They expanded on the original ideas of Robert Rosen and Howard Pattee regarding quantum measurement in living systems viewed as natural internal observers that belong to the same scale of the observed objects. According to Matsuno, an internal measurement is accompanied by a redistribution of probabilities that leave them entangled in accordance with the many-worlds interpretation of quantum mechanics by Everett. However, this form of quantum entanglement does not survive in an external measurement, in which the mapping to real numbers takes place and the result is revealed in classical spacetime, as the Copenhagen interpretation suggests. This means that the internal measurement concept unifies the current alternative interpretations of quantum mechanics.
Internal measurement and theoretical biology
The concept of internal measurement is important for theoretical biology, as living organisms can be regarded as endo-observers having their internal self-referential encoding. An internal measurement leads to an iterative recursive process which appears as the development and evolution of the system where any solution is destined to be relative. The evolutionary increase of complexity becomes possible when the genotype emerges as a system distinct from the phenotype and embedded into it, which separates energy-degenerate rate-independent genetic symbols from the rate-dependent dynamics of construction that they control. Evolution in this concept, which is related to autopoiesis, becomes its own cause, a universal property of our world.
Internal measurement and the problem of self
The self can be attributed to the internal quantum state with entangled probabilities. This entanglement can be held for prolonged times in the systems with low dissipation without demolition. According to Matsuno, organisms exploit thermodynamic gradients by acting as heat engines to drastically reduce the effective temperature within macromolecular complexes which can potentially provide the maintenance of long-living coherent states in the microtubules of nervous system. The concept of internal measurement develops the ideas of Schrödinger who suggested in "What is life?" that the nature of the self is quantum mechanical, i.e. the self is attributed to an internal state beyond quantum reduction, which generates emergent events by applying quantum reduction externally and observing it.
See also
Endophysics
Interpretations of quantum mechanics
Autopoiesis
References
Philosophical theories
Measurement | Internal measurement | Physics,Mathematics | 547 |
45,410,332 | https://en.wikipedia.org/wiki/Semi-Yao%20graph | The k-semi-Yao graph (k-SYG) of a set of n objects P is a geometric proximity graph, which was first described to present a kinetic data structure for maintenance of all the nearest neighbors on moving objects. It is named for its relation to the Yao graph, which is named after Andrew Yao.
Construction
The k-SYG is constructed as follows. The space around each point p in P is partitioned into a set of polyhedral cones of opening angle , meaning the angle of each pair of rays inside a polyhedral cone emanating from the apex is at most , and then p connects to k points of P in each of the polyhedral cones whose projections on the cone axis is minimum.
Properties
The k-SYG, where k = 1, is known as the theta graph, and is the union of two Delaunay triangulations.
For a small and an appropriate cone axis, the k-SYG gives a supergraph of the k-nearest neighbor graph (k-NNG). For example, in 2D, if we partition the plane around each point into six wedges of equal angles, and pick the cone axes on directions of the cone bisectors, we obtain a k-SYG as a supergraph for the k-NNG.
See also
Geometric spanner
References
Computational geometry
Geometric graphs | Semi-Yao graph | Mathematics | 277 |
3,196,565 | https://en.wikipedia.org/wiki/Fish%20hatchery | A fish hatchery is a place for artificial breeding, hatching, and rearing through the early life stages of animals—finfish and shellfish in particular. Hatcheries produce larval and juvenile fish, shellfish, and crustaceans, primarily to support the aquaculture industry where they are transferred to on-growing systems, such as fish farms, to reach harvest size. Some species that are commonly raised in hatcheries include Pacific oysters, shrimp, Indian prawns, salmon, tilapia and scallops.
The value of global aquaculture farming is estimated to be US$98.4 billion in 2008 with China significantly dominating the market; however, the value of aquaculture hatchery and nursery production has yet to be estimated. Additional hatchery production for small-scale domestic uses, which is particularly prevalent in South-East Asia or for conservation programmes, has also yet to be quantified.
There is much interest in supplementing exploited stocks of fish by releasing juveniles that may be wild caught and reared in nurseries before transplanting, or produced solely within a hatchery. Culture of finfish larvae has been utilised extensively in the United States in stock enhancement efforts to replenish natural populations. The U.S. Fish and Wildlife Service have established a National Fish Hatchery System to support the conservation of native fish species.
Purpose
Hatcheries produce larval and juvenile fish and shellfish for transferral to aquaculture facilities where they are ‘on-grown’ to reach harvest size. Hatchery production confers three main benefits to the industry:
1. Out of season production
Consistent supply of fish from aquaculture facilities is an important market requirement. Broodstock conditioning can extend the natural spawning season and thus the supply of juveniles to farms. Supply can be further guaranteed by sourcing from hatcheries in the opposite hemisphere i.e. with opposite seasons.
2. Genetic improvement
Genetic modification is conducted in some hatcheries to improve the quality and yield of farmed species. Artificial fertilisation facilitates selective breeding programs which aim to improve production characteristics such as growth rate, disease resistance, survival, colour, increased fecundity and/or lower age of maturation. Genetic improvement can be mediated by selective breeding, via hybridization, or other genetic manipulation techniques.
3. Reduce dependence on wild-caught juveniles
In 2008 aquaculture accounted for 46% of total food fish supply, around 115 million tonnes. Although wild caught juveniles are still utilised in the industry, concerns over sustainability of extracting juveniles, and the variable timing and magnitude of natural spawning events, make hatchery production an attractive alternative to support the growing demands of aquaculture.
Production steps
Broodstock
Broodstock conditioning is the process of bringing adults into spawning condition by promoting the development of gonads. Broodstock conditioning can also extend spawning beyond natural spawning periods, or for production of species reared outside their natural geographic range with different environmental conditions. Some hatcheries collect wild adults and then bring them in for conditioning whilst others maintain a permanent breeding stock.
Conditioning is achieved by holding broodstock in flow-through tanks at optimal conditions for light, temperature, salinity, flow rate and food availability (optimal levels are species specific).
Another important aspect of broodstock conditioning is ensuring the production of high quality eggs to improve growth and survival of larvae by optimising the health and welfare of broodstock individuals. Egg quality is often determined by the nutritional condition of the mother. High levels of lipid reserves in particular are required to improve larval survival rates.
Spawning
Natural spawning can occur in hatcheries during the regular spawning season however where more control over spawning time is required spawning of mature animals can be induced by a variety of methods. Some of the more common methods are:
Manual stripping: For shellfish, gonads are generally removed and gametes are extracted or washed free. Fish can be manually stripped of eggs and sperm by stroking the anaesthetised fish under the pectoral fins towards the anus causing gametes to freely flow out.
Environmental manipulation: Thermal shock, where cool water is alternated with warmer water in flow-through tanks can induce spawning. Alternatively, if environmental cues that stimulate natural spawning are known, these can be mimicked in the tank e.g. changing salinity to simulate migratory behaviour. Many individuals can be induced to spawn this way, however this increases the likelihood of uncontrolled fertilisation occurring.
Chemical injection: A number of chemicals can be used to induce spawning with various hormones being the most commonly used.
Fertilisation
Prior to fertilisation, eggs can be gently washed to remove wastes and bacteria that may contaminate cultures. Promoting cross-fertilisation between a large number of individuals is necessary to retain genetic diversity in hatchery produced stock. Batches of eggs are kept separate, fertilised with sperm obtained from several males and allowed to stand for an hour or two before samples are analyzed under a microscope to ensure high rates of fertilisation and to estimate numbers to be transferred to larval rearing tanks.
Larvae
Rearing larvae through the early life stages is conducted in nurseries which are generally closely associated with hatcheries for fish culture whilst it is common for shellfish nurseries to exist separately. Nursery culture of larvae to rear juveniles of a size suitable for transferral to on-growing facilities can be performed in a variety of different systems which may be entirely land-based, or larvae may be later transferred to sea-based rearing systems which reduce the need to supply feed. Juvenile survival is dependent on very high quality water conditions.
Feeding is an important component of the rearing process. Although many species are able to grow on maternal reserves alone (lecithotrophy), most commercially produced species require feeding to optimise survival, growth, yield and juvenile quality. Nutritional requirements are species specific and also vary with larval stage. Carnivorous fish are commonly fed with live prey; rotifers are usually offered to early larvae due to their small size, progressing to larger Artemia nauplii or zooplankton. The production of live feed on-site or buying-in is one of the biggest costs for hatchery facilities as it is a labour-intensive process. The development of artificial feeds is targeted to reduce the costs involved in live feed production and increase the consistency of nutrition, however decreased growth and survival has been found with these alternatives.
Settlement of shellfish
The hatchery production of shellfish also involves a crucial settling phase where free-swimming larvae settle out of the water onto a substrate and undergo metamorphosis if suitable conditions are found. Once metamorphosis has taken place the juveniles are generally known as spat, it is this phase which is then transported to on-growing facilities. Settlement behaviour is governed by a range of cues including substrate type, water flow, temperature, and the presence of chemical cues indicating the presence of adults, or a food source etc. Hatchery facilities therefore need to understand these cues to induce settlement and also be able to substitute artificial substrates to allow for easy handling and transportation with minimal mortality.
Hatchery design
Hatchery designs are highly flexible and are tailored to the requirements of site, species produced, geographic location, funding and personal preferences. Many hatchery facilities are small and coupled to larger on-growing operations, whilst others may produce juveniles solely for sale. Very small-scale hatcheries are often utilized in subsistence farming to supply families or communities particularly in south-east Asia. A small-scale hatchery unit consists of larval rearing tanks, filters, live food production tanks and a flow through water supply.
A generalized commercial scale hatchery would contain a broodstock holding and spawning area, feed culture facility, larval culture area, juvenile culture area, pump facilities, laboratory, quarantine area, and offices and bathrooms.
Expense
Labour is generally the largest cost in hatchery production making up more than 50% of total costs. Hatcheries are a business and thus economic viability and scale of production are vital considerations. The cost of production for stock-enhancement programmes is further complicated by the difficulty of assessing the benefits to wild populations from restocking activities.
Issues
Genetic
Hatchery facilities present three main problems in the field of genetics. The first is that maintenance of a small number of broodstock can cause inbreeding and potentially lead to inbreeding depression thus affecting the success of the facility. Secondly, hatchery reared juveniles, even from a fairly large broodstock, can have greatly reduced genetic diversity compared to wild populations (the situation is comparable to the founder effect). Such fish that escape from farms or are released for restocking purposes may adversely affect wild population genetics and viability. This is of particular concern where escaped fish have been actively bred or are otherwise genetically modified. The third key issue is that genetic modification of food items is highly undesirable for many people. See Genetically modified food controversies.
Fish farms
Other arguments that surround fish farms such as the supplementation of feed from wild caught species, the prevalence of disease, fish welfare issues and potential effects on the environment are also issues for hatchery facilities.
See also
List of harvested aquatic animals by weight
Caledonia Fish Hatchery
Mount Whitney Fish Hatchery
Raceway (aquaculture)
USFC Fish Hawk
References
External links
Intensive farming
Fish farming
Fish hatcheries | Fish hatchery | Chemistry | 1,893 |
1,809,181 | https://en.wikipedia.org/wiki/Mathematical%20structure | In mathematics, a structure on a set (or on some sets) refers to providing it (or them) with certain additional features (e.g. an operation, relation, metric, or topology). Τhe additional features are attached or related to the set (or to the sets), so as to provide it (or them) with some additional meaning or significance.
A partial list of possible structures are measures, algebraic structures (groups, fields, etc.), topologies, metric structures (geometries), orders, graphs, events, equivalence relations, differential structures, and categories.
Sometimes, a set is endowed with more than one feature simultaneously, which allows mathematicians to study the interaction between the different structures more richly. For example, an ordering imposes a rigid form, shape, or topology on the set, and if a set has both a topology feature and a group feature, such that these two features are related in a certain way, then the structure becomes a topological group.
Map between two sets with the same type of structure, which preserve this structure [morphism: structure in the domain is mapped properly to the (same type) structure in the codomain] is of special interest in many fields of mathematics. Examples are homomorphisms, which preserve algebraic structures; continuous functions, which preserve topological structures; and differentiable functions, which preserve differential structures.
History
In 1939, the French group with the pseudonym Nicolas Bourbaki saw structures as the root of mathematics. They first mentioned them in their "Fascicule" of Theory of Sets and expanded it into Chapter IV of the 1957 edition. They identified three mother structures: algebraic, topological, and order.
Example: the real numbers
The set of real numbers has several standard structures:
An order: each number is either less than or greater than any other number.
Algebraic structure: there are operations of addition and multiplication, the first of which makes it into a group and the pair of which together make it into a field.
A measure: intervals of the real line have a specific length, which can be extended to the Lebesgue measure on many of its subsets.
A metric: there is a notion of distance between points.
A geometry: it is equipped with a metric and is flat.
A topology: there is a notion of open sets.
There are interfaces among these:
Its order and, independently, its metric structure induce its topology.
Its order and algebraic structure make it into an ordered field.
Its algebraic structure and topology make it into a Lie group, a type of topological group.
See also
Abstract structure
Isomorphism
Equivalent definitions of mathematical structures
Intuitionistic type theory
Mathematical object
Algebraic structure
Space (mathematics)
Category (mathematics)
References
Further reading
Bourbaki, Nikolas (1968). "Elements of Mathematics: Theory of Sets". Hermann, Addison-Wesley. pp. 259–346, 383–385.
External links
(provides a model theoretic definition.)
Mathematical structures in computer science (journal)
Type theory
Set theory | Mathematical structure | Mathematics | 617 |
65,578,796 | https://en.wikipedia.org/wiki/CYP9%20family | Cytochrome P450, family 9, also known as CYP9, is a cytochrome P450 family found in Insect genome, CYP9 and insect CYP6 family belong to the same clan as mammalian CYP3 and CYP5 families. The first gene identified in this family is the CYP9A1 from the Heliothis virescens (tobacco budworm), which is involved in thiodicarb insecticide resistance. Subfamily CYP9A in Lepidopteran play important roles in insecticide resistance, can metabolize esfenvalerate efficiently.
References
Insect genes
9
Protein families | CYP9 family | Biology | 133 |
52,085 | https://en.wikipedia.org/wiki/Protein%20folding | Protein folding is the physical process by which a protein, after synthesis by a ribosome as a linear chain of amino acids, changes from an unstable random coil into a more ordered three-dimensional structure. This structure permits the protein to become biologically functional.
The folding of many proteins begins even during the translation of the polypeptide chain. The amino acids interact with each other to produce a well-defined three-dimensional structure, known as the protein's native state. This structure is determined by the amino-acid sequence or primary structure.
The correct three-dimensional structure is essential to function, although some parts of functional proteins may remain unfolded, indicating that protein dynamics are important. Failure to fold into a native structure generally produces inactive proteins, but in some instances, misfolded proteins have modified or toxic functionality. Several neurodegenerative and other diseases are believed to result from the accumulation of amyloid fibrils formed by misfolded proteins, the infectious varieties of which are known as prions. Many allergies are caused by the incorrect folding of some proteins because the immune system does not produce the antibodies for certain protein structures.
Denaturation of proteins is a process of transition from a folded to an unfolded state. It happens in cooking, burns, proteinopathies, and other contexts. Residual structure present, if any, in the supposedly unfolded state may form a folding initiation site and guide the subsequent folding reactions.
The duration of the folding process varies dramatically depending on the protein of interest. When studied outside the cell, the slowest folding proteins require many minutes or hours to fold, primarily due to proline isomerization, and must pass through a number of intermediate states, like checkpoints, before the process is complete. On the other hand, very small single-domain proteins with lengths of up to a hundred amino acids typically fold in a single step. Time scales of milliseconds are the norm, and the fastest known protein folding reactions are complete within a few microseconds. The folding time scale of a protein depends on its size, contact order, and circuit topology.
Understanding and simulating the protein folding process has been an important challenge for computational biology since the late 1960s.
Process of protein folding
Primary structure
The primary structure of a protein, its linear amino-acid sequence, determines its native conformation. The specific amino acid residues and their position in the polypeptide chain are the determining factors for which portions of the protein fold closely together and form its three-dimensional conformation. The amino acid composition is not as important as the sequence. The essential fact of folding, however, remains that the amino acid sequence of each protein contains the information that specifies both the native structure and the pathway to attain that state. This is not to say that nearly identical amino acid sequences always fold similarly. Conformations differ based on environmental factors as well; similar proteins fold differently based on where they are found.
Secondary structure
Formation of a secondary structure is the first step in the folding process that a protein takes to assume its native structure. Characteristic of secondary structure are the structures known as alpha helices and beta sheets that fold rapidly because they are stabilized by intramolecular hydrogen bonds, as was first characterized by Linus Pauling. Formation of intramolecular hydrogen bonds provides another important contribution to protein stability. α-helices are formed by hydrogen bonding of the backbone to form a spiral shape (refer to figure on the right). The β pleated sheet is a structure that forms with the backbone bending over itself to form the hydrogen bonds (as displayed in the figure to the left). The hydrogen bonds are between the amide hydrogen and carbonyl oxygen of the peptide bond. There exists anti-parallel β pleated sheets and parallel β pleated sheets where the stability of the hydrogen bonds is stronger in the anti-parallel β sheet as it hydrogen bonds with the ideal 180 degree angle compared to the slanted hydrogen bonds formed by parallel sheets.
Tertiary structure
The α-Helices and β-Sheets are commonly amphipathic, meaning they have a hydrophilic and a hydrophobic portion. This ability helps in forming tertiary structure of a protein in which folding occurs so that the hydrophilic sides are facing the aqueous environment surrounding the protein and the hydrophobic sides are facing the hydrophobic core of the protein. Secondary structure hierarchically gives way to tertiary structure formation. Once the protein's tertiary structure is formed and stabilized by the hydrophobic interactions, there may also be covalent bonding in the form of disulfide bridges formed between two cysteine residues. These non-covalent and covalent contacts take a specific topological arrangement in a native structure of a protein. Tertiary structure of a protein involves a single polypeptide chain; however, additional interactions of folded polypeptide chains give rise to quaternary structure formation.
Quaternary structure
Tertiary structure may give way to the formation of quaternary structure in some proteins, which usually involves the "assembly" or "coassembly" of subunits that have already folded; in other words, multiple polypeptide chains could interact to form a fully functional quaternary protein.
Driving forces of protein folding
Folding is a spontaneous process that is mainly guided by hydrophobic interactions, formation of intramolecular hydrogen bonds, van der Waals forces, and it is opposed by conformational entropy. The folding time scale of an isolated protein depends on its size, contact order, and circuit topology. Inside cells, the process of folding often begins co-translationally, so that the N-terminus of the protein begins to fold while the C-terminal portion of the protein is still being synthesized by the ribosome; however, a protein molecule may fold spontaneously during or after biosynthesis. While these macromolecules may be regarded as "folding themselves", the process also depends on the solvent (water or lipid bilayer), the concentration of salts, the pH, the temperature, the possible presence of cofactors and of molecular chaperones.
Proteins will have limitations on their folding abilities by the restricted bending angles or conformations that are possible. These allowable angles of protein folding are described with a two-dimensional plot known as the Ramachandran plot, depicted with psi and phi angles of allowable rotation.
Hydrophobic effect
Protein folding must be thermodynamically favorable within a cell in order for it to be a spontaneous reaction. Since it is known that protein folding is a spontaneous reaction, then it must assume a negative Gibbs free energy value. Gibbs free energy in protein folding is directly related to enthalpy and entropy. For a negative delta G to arise and for protein folding to become thermodynamically favorable, then either enthalpy, entropy, or both terms must be favorable.
Minimizing the number of hydrophobic side-chains exposed to water is an important driving force behind the folding process. The hydrophobic effect is the phenomenon in which the hydrophobic chains of a protein collapse into the core of the protein (away from the hydrophilic environment). In an aqueous environment, the water molecules tend to aggregate around the hydrophobic regions or side chains of the protein, creating water shells of ordered water molecules. An ordering of water molecules around a hydrophobic region increases order in a system and therefore contributes a negative change in entropy (less entropy in the system). The water molecules are fixed in these water cages which drives the hydrophobic collapse, or the inward folding of the hydrophobic groups. The hydrophobic collapse introduces entropy back to the system via the breaking of the water cages which frees the ordered water molecules. The multitude of hydrophobic groups interacting within the core of the globular folded protein contributes a significant amount to protein stability after folding, because of the vastly accumulated van der Waals forces (specifically London Dispersion forces). The hydrophobic effect exists as a driving force in thermodynamics only if there is the presence of an aqueous medium with an amphiphilic molecule containing a large hydrophobic region. The strength of hydrogen bonds depends on their environment; thus, H-bonds enveloped in a hydrophobic core contribute more than H-bonds exposed to the aqueous environment to the stability of the native state.
In proteins with globular folds, hydrophobic amino acids tend to be interspersed along the primary sequence, rather than randomly distributed or clustered together. However, proteins that have recently been born de novo, which tend to be intrinsically disordered, show the opposite pattern of hydrophobic amino acid clustering along the primary sequence.
Chaperones
Molecular chaperones are a class of proteins that aid in the correct folding of other proteins in vivo. Chaperones exist in all cellular compartments and interact with the polypeptide chain in order to allow the native three-dimensional conformation of the protein to form; however, chaperones themselves are not included in the final structure of the protein they are assisting in. Chaperones may assist in folding even when the nascent polypeptide is being synthesized by the ribosome. Molecular chaperones operate by binding to stabilize an otherwise unstable structure of a protein in its folding pathway, but chaperones do not contain the necessary information to know the correct native structure of the protein they are aiding; rather, chaperones work by preventing incorrect folding conformations. In this way, chaperones do not actually increase the rate of individual steps involved in the folding pathway toward the native structure; instead, they work by reducing possible unwanted aggregations of the polypeptide chain that might otherwise slow down the search for the proper intermediate and they provide a more efficient pathway for the polypeptide chain to assume the correct conformations. Chaperones are not to be confused with folding catalyst proteins, which catalyze chemical reactions responsible for slow steps in folding pathways. Examples of folding catalysts are protein disulfide isomerases and peptidyl-prolyl isomerases that may be involved in formation of disulfide bonds or interconversion between cis and trans stereoisomers of peptide group. Chaperones are shown to be critical in the process of protein folding in vivo because they provide the protein with the aid needed to assume its proper alignments and conformations efficiently enough to become "biologically relevant". This means that the polypeptide chain could theoretically fold into its native structure without the aid of chaperones, as demonstrated by protein folding experiments conducted in vitro; however, this process proves to be too inefficient or too slow to exist in biological systems; therefore, chaperones are necessary for protein folding in vivo. Along with its role in aiding native structure formation, chaperones are shown to be involved in various roles such as protein transport, degradation, and even allow denatured proteins exposed to certain external denaturant factors an opportunity to refold into their correct native structures.
A fully denatured protein lacks both tertiary and secondary structure, and exists as a so-called random coil. Under certain conditions some proteins can refold; however, in many cases, denaturation is irreversible. Cells sometimes protect their proteins against the denaturing influence of heat with enzymes known as heat shock proteins (a type of chaperone), which assist other proteins both in folding and in remaining folded. Heat shock proteins have been found in all species examined, from bacteria to humans, suggesting that they evolved very early and have an important function. Some proteins never fold in cells at all except with the assistance of chaperones which either isolate individual proteins so that their folding is not interrupted by interactions with other proteins or help to unfold misfolded proteins, allowing them to refold into the correct native structure. This function is crucial to prevent the risk of precipitation into insoluble amorphous aggregates. The external factors involved in protein denaturation or disruption of the native state include temperature, external fields (electric, magnetic), molecular crowding, and even the limitation of space (i.e. confinement), which can have a big influence on the folding of proteins. High concentrations of solutes, extremes of pH, mechanical forces, and the presence of chemical denaturants can contribute to protein denaturation, as well. These individual factors are categorized together as stresses. Chaperones are shown to exist in increasing concentrations during times of cellular stress and help the proper folding of emerging proteins as well as denatured or misfolded ones.
Under some conditions proteins will not fold into their biochemically functional forms. Temperatures above or below the range that cells tend to live in will cause thermally unstable proteins to unfold or denature (this is why boiling makes an egg white turn opaque). Protein thermal stability is far from constant, however; for example, hyperthermophilic bacteria have been found that grow at temperatures as high as 122 °C, which of course requires that their full complement of vital proteins and protein assemblies be stable at that temperature or above.
The bacterium E. coli is the host for bacteriophage T4, and the phage encoded gp31 protein () appears to be structurally and functionally homologous to E. coli chaperone protein GroES and able to substitute for it in the assembly of bacteriophage T4 virus particles during infection. Like GroES, gp31 forms a stable complex with GroEL chaperonin that is absolutely necessary for the folding and assembly in vivo of the bacteriophage T4 major capsid protein gp23.
Fold switching
Some proteins have multiple native structures, and change their fold based on some external factors. For example, the KaiB protein switches fold throughout the day, acting as a clock for cyanobacteria. It has been estimated that around 0.5–4% of PDB (Protein Data Bank) proteins switch folds.
Protein misfolding and neurodegenerative disease
A protein is considered to be misfolded if it cannot achieve its normal native state. This can be due to mutations in the amino acid sequence or a disruption of the normal folding process by external factors. The misfolded protein typically contains β-sheets that are organized in a supramolecular arrangement known as a cross-β structure. These β-sheet-rich assemblies are very stable, very insoluble, and generally resistant to proteolysis. The structural stability of these fibrillar assemblies is caused by extensive interactions between the protein monomers, formed by backbone hydrogen bonds between their β-strands. The misfolding of proteins can trigger the further misfolding and accumulation of other proteins into aggregates or oligomers. The increased levels of aggregated proteins in the cell leads to formation of amyloid-like structures which can cause degenerative disorders and cell death. The amyloids are fibrillary structures that contain intermolecular hydrogen bonds which are highly insoluble and made from converted protein aggregates. Therefore, the proteasome pathway may not be efficient enough to degrade the misfolded proteins prior to aggregation. Misfolded proteins can interact with one another and form structured aggregates and gain toxicity through intermolecular interactions.
Aggregated proteins are associated with prion-related illnesses such as Creutzfeldt–Jakob disease, bovine spongiform encephalopathy (mad cow disease), amyloid-related illnesses such as Alzheimer's disease and familial amyloid cardiomyopathy or polyneuropathy, as well as intracellular aggregation diseases such as Huntington's and Parkinson's disease. These age onset degenerative diseases are associated with the aggregation of misfolded proteins into insoluble, extracellular aggregates and/or intracellular inclusions including cross-β amyloid fibrils. It is not completely clear whether the aggregates are the cause or merely a reflection of the loss of protein homeostasis, the balance between synthesis, folding, aggregation and protein turnover. Recently the European Medicines Agency approved the use of Tafamidis or Vyndaqel (a kinetic stabilizer of tetrameric transthyretin) for the treatment of transthyretin amyloid diseases. This suggests that the process of amyloid fibril formation (and not the fibrils themselves) causes the degeneration of post-mitotic tissue in human amyloid diseases. Misfolding and excessive degradation instead of folding and function leads to a number of proteopathy diseases such as antitrypsin-associated emphysema, cystic fibrosis and the lysosomal storage diseases, where loss of function is the origin of the disorder. While protein replacement therapy has historically been used to correct the latter disorders, an emerging approach is to use pharmaceutical chaperones to fold mutated proteins to render them functional.
Experimental techniques for studying protein folding
While inferences about protein folding can be made through mutation studies, typically, experimental techniques for studying protein folding rely on the gradual unfolding or folding of proteins and observing conformational changes using standard non-crystallographic techniques.
X-ray crystallography
X-ray crystallography is one of the more efficient and important methods for attempting to decipher the three dimensional configuration of a folded protein. To be able to conduct X-ray crystallography, the protein under investigation must be located inside a crystal lattice. To place a protein inside a crystal lattice, one must have a suitable solvent for crystallization, obtain a pure protein at supersaturated levels in solution, and precipitate the crystals in solution. Once a protein is crystallized, X-ray beams can be concentrated through the crystal lattice which would diffract the beams or shoot them outwards in various directions. These exiting beams are correlated to the specific three-dimensional configuration of the protein enclosed within. The X-rays specifically interact with the electron clouds surrounding the individual atoms within the protein crystal lattice and produce a discernible diffraction pattern. Only by relating the electron density clouds with the amplitude of the X-rays can this pattern be read and lead to assumptions of the phases or phase angles involved that complicate this method. Without the relation established through a mathematical basis known as Fourier transform, the "phase problem" would render predicting the diffraction patterns very difficult. Emerging methods like multiple isomorphous replacement use the presence of a heavy metal ion to diffract the X-rays into a more predictable manner, reducing the number of variables involved and resolving the phase problem.
Fluorescence spectroscopy
Fluorescence spectroscopy is a highly sensitive method for studying the folding state of proteins. Three amino acids, phenylalanine (Phe), tyrosine (Tyr) and tryptophan (Trp), have intrinsic fluorescence properties, but only Tyr and Trp are used experimentally because their quantum yields are high enough to give good fluorescence signals. Both Trp and Tyr are excited by a wavelength of 280 nm, whereas only Trp is excited by a wavelength of 295 nm. Because of their aromatic character, Trp and Tyr residues are often found fully or partially buried in the hydrophobic core of proteins, at the interface between two protein domains, or at the interface between subunits of oligomeric proteins. In this apolar environment, they have high quantum yields and therefore high fluorescence intensities. Upon disruption of the protein's tertiary or quaternary structure, these side chains become more exposed to the hydrophilic environment of the solvent, and their quantum yields decrease, leading to low fluorescence intensities. For Trp residues, the wavelength of their maximal fluorescence emission also depend on their environment.
Fluorescence spectroscopy can be used to characterize the equilibrium unfolding of proteins by measuring the variation in the intensity of fluorescence emission or in the wavelength of maximal emission as functions of a denaturant value. The denaturant can be a chemical molecule (urea, guanidinium hydrochloride), temperature, pH, pressure, etc. The equilibrium between the different but discrete protein states, i.e. native state, intermediate states, unfolded state, depends on the denaturant value; therefore, the global fluorescence signal of their equilibrium mixture also depends on this value. One thus obtains a profile relating the global protein signal to the denaturant value. The profile of equilibrium unfolding may enable one to detect and identify intermediates of unfolding. General equations have been developed by Hugues Bedouelle to obtain the thermodynamic parameters that characterize the unfolding equilibria for homomeric or heteromeric proteins, up to trimers and potentially tetramers, from such profiles. Fluorescence spectroscopy can be combined with fast-mixing devices such as stopped flow, to measure protein folding kinetics, generate a chevron plot and derive a Phi value analysis.
Circular dichroism
Circular dichroism is one of the most general and basic tools to study protein folding. Circular dichroism spectroscopy measures the absorption of circularly polarized light. In proteins, structures such as alpha helices and beta sheets are chiral, and thus absorb such light. The absorption of this light acts as a marker of the degree of foldedness of the protein ensemble. This technique has been used to measure equilibrium unfolding of the protein by measuring the change in this absorption as a function of denaturant concentration or temperature. A denaturant melt measures the free energy of unfolding as well as the protein's m value, or denaturant dependence. A temperature melt measures the denaturation temperature (Tm) of the protein. As for fluorescence spectroscopy, circular-dichroism spectroscopy can be combined with fast-mixing devices such as stopped flow to measure protein folding kinetics and to generate chevron plots.
Vibrational circular dichroism of proteins
The more recent developments of vibrational circular dichroism (VCD) techniques for proteins, currently involving Fourier transform (FT) instruments, provide powerful means for determining protein conformations in solution even for very large protein molecules. Such VCD studies of proteins can be combined with X-ray diffraction data for protein crystals, FT-IR data for protein solutions in heavy water (D2O), or quantum computations.
Protein nuclear magnetic resonance spectroscopy
Protein nuclear magnetic resonance (NMR) is able to collect protein structural data by inducing a magnet field through samples of concentrated protein. In NMR, depending on the chemical environment, certain nuclei will absorb specific radio-frequencies. Because protein structural changes operate on a time scale from ns to ms, NMR is especially equipped to study intermediate structures in timescales of ps to s. Some of the main techniques for studying proteins structure and non-folding protein structural changes include COSY, TOCSY, HSQC, time relaxation (T1 & T2), and NOE. NOE is especially useful because magnetization transfers can be observed between spatially proximal hydrogens are observed. Different NMR experiments have varying degrees of timescale sensitivity that are appropriate for different protein structural changes. NOE can pick up bond vibrations or side chain rotations, however, NOE is too sensitive to pick up protein folding because it occurs at larger timescale.
Because protein folding takes place in about 50 to 3000 s−1 CPMG Relaxation dispersion and chemical exchange saturation transfer have become some of the primary techniques for NMR analysis of folding. In addition, both techniques are used to uncover excited intermediate states in the protein folding landscape. To do this, CPMG Relaxation dispersion takes advantage of the spin echo phenomenon. This technique exposes the target nuclei to a 90 pulse followed by one or more 180 pulses. As the nuclei refocus, a broad distribution indicates the target nuclei is involved in an intermediate excited state. By looking at Relaxation dispersion plots the data collect information on the thermodynamics and kinetics between the excited and ground. Saturation Transfer measures changes in signal from the ground state as excited states become perturbed. It uses weak radio frequency irradiation to saturate the excited state of a particular nuclei which transfers its saturation to the ground state. This signal is amplified by decreasing the magnetization (and the signal) of the ground state.
The main limitations in NMR is that its resolution decreases with proteins that are larger than 25 kDa and is not as detailed as X-ray crystallography. Additionally, protein NMR analysis is quite difficult and can propose multiple solutions from the same NMR spectrum.
In a study focused on the folding of an amyotrophic lateral sclerosis involved protein SOD1, excited intermediates were studied with relaxation dispersion and Saturation transfer. SOD1 had been previously tied to many disease causing mutants which were assumed to be involved in protein aggregation, however the mechanism was still unknown. By using Relaxation Dispersion and Saturation Transfer experiments many excited intermediate states were uncovered misfolding in the SOD1 mutants.
Dual-polarization interferometry
Dual polarisation interferometry is a surface-based technique for measuring the optical properties of molecular layers. When used to characterize protein folding, it measures the conformation by determining the overall size of a monolayer of the protein and its density in real time at sub-Angstrom resolution, although real-time measurement of the kinetics of protein folding are limited to processes that occur slower than ~10 Hz. Similar to circular dichroism, the stimulus for folding can be a denaturant or temperature.
Studies of folding with high time resolution
The study of protein folding has been greatly advanced in recent years by the development of fast, time-resolved techniques. Experimenters rapidly trigger the folding of a sample of unfolded protein and observe the resulting dynamics. Fast techniques in use include neutron scattering, ultrafast mixing of solutions, photochemical methods, and laser temperature jump spectroscopy. Among the many scientists who have contributed to the development of these techniques are Jeremy Cook, Heinrich Roder, Terry Oas, Harry Gray, Martin Gruebele, Brian Dyer, William Eaton, Sheena Radford, Chris Dobson, Alan Fersht, Bengt Nölting and Lars Konermann.
Proteolysis
Proteolysis is routinely used to probe the fraction unfolded under a wide range of solution conditions (e.g. fast parallel proteolysis (FASTpp).
Single-molecule force spectroscopy
Single molecule techniques such as optical tweezers and AFM have been used to understand protein folding mechanisms of isolated proteins as well as proteins with chaperones. Optical tweezers have been used to stretch single protein molecules from their C- and N-termini and unfold them to allow study of the subsequent refolding. The technique allows one to measure folding rates at single-molecule level; for example, optical tweezers have been recently applied to study folding and unfolding of proteins involved in blood coagulation. von Willebrand factor (vWF) is a protein with an essential role in blood clot formation process. It discovered – using single molecule optical tweezers measurement – that calcium-bound vWF acts as a shear force sensor in the blood. Shear force leads to unfolding of the A2 domain of vWF, whose refolding rate is dramatically enhanced in the presence of calcium. Recently, it was also shown that the simple src SH3 domain accesses multiple unfolding pathways under force.
Biotin painting
Biotin painting enables condition-specific cellular snapshots of (un)folded proteins. Biotin 'painting' shows a bias towards predicted Intrinsically disordered proteins.
Computational studies of protein folding
Computational studies of protein folding includes three main aspects related to the prediction of protein stability, kinetics, and structure. A 2013 review summarizes the available computational methods for protein folding.
Levinthal's paradox
In 1969, Cyrus Levinthal noted that, because of the very large number of degrees of freedom in an unfolded polypeptide chain, the molecule has an astronomical number of possible conformations. An estimate of 3300 or 10143 was made in one of his papers. Levinthal's paradox is a thought experiment based on the observation that if a protein were folded by sequential sampling of all possible conformations, it would take an astronomical amount of time to do so, even if the conformations were sampled at a rapid rate (on the nanosecond or picosecond scale). Based upon the observation that proteins fold much faster than this, Levinthal then proposed that a random conformational search does not occur, and the protein must, therefore, fold through a series of meta-stable intermediate states.
Energy landscape of protein folding
The configuration space of a protein during folding can be visualized as an energy landscape. According to Joseph Bryngelson and Peter Wolynes, proteins follow the principle of minimal frustration, meaning that naturally evolved proteins have optimized their folding energy landscapes, and that nature has chosen amino acid sequences so that the folded state of the protein is sufficiently stable. In addition, the acquisition of the folded state had to become a sufficiently fast process. Even though nature has reduced the level of frustration in proteins, some degree of it remains up to now as can be observed in the presence of local minima in the energy landscape of proteins.
A consequence of these evolutionarily selected sequences is that proteins are generally thought to have globally "funneled energy landscapes" (a term coined by José Onuchic) that are largely directed toward the native state. This "folding funnel" landscape allows the protein to fold to the native state through any of a large number of pathways and intermediates, rather than being restricted to a single mechanism. The theory is supported by both computational simulations of model proteins and experimental studies, and it has been used to improve methods for protein structure prediction and design. The description of protein folding by the leveling free-energy landscape is also consistent with the 2nd law of thermodynamics. Physically, thinking of landscapes in terms of visualizable potential or total energy surfaces simply with maxima, saddle points, minima, and funnels, rather like geographic landscapes, is perhaps a little misleading. The relevant description is really a high-dimensional phase space in which manifolds might take a variety of more complicated topological forms.
The unfolded polypeptide chain begins at the top of the funnel where it may assume the largest number of unfolded variations and is in its highest energy state. Energy landscapes such as these indicate that there are a large number of initial possibilities, but only a single native state is possible; however, it does not reveal the numerous folding pathways that are possible. A different molecule of the same exact protein may be able to follow marginally different folding pathways, seeking different lower energy intermediates, as long as the same native structure is reached. Different pathways may have different frequencies of utilization depending on the thermodynamic favorability of each pathway. This means that if one pathway is found to be more thermodynamically favorable than another, it is likely to be used more frequently in the pursuit of the native structure. As the protein begins to fold and assume its various conformations, it always seeks a more thermodynamically favorable structure than before and thus continues through the energy funnel. Formation of secondary structures is a strong indication of increased stability within the protein, and only one combination of secondary structures assumed by the polypeptide backbone will have the lowest energy and therefore be present in the native state of the protein. Among the first structures to form once the polypeptide begins to fold are alpha helices and beta turns, where alpha helices can form in as little as 100 nanoseconds and beta turns in 1 microsecond.
There exists a saddle point in the energy funnel landscape where the transition state for a particular protein is found. The transition state in the energy funnel diagram is the conformation that must be assumed by every molecule of that protein if the protein wishes to finally assume the native structure. No protein may assume the native structure without first passing through the transition state. The transition state can be referred to as a variant or premature form of the native state rather than just another intermediary step. The folding of the transition state is shown to be rate-determining, and even though it exists in a higher energy state than the native fold, it greatly resembles the native structure. Within the transition state, there exists a nucleus around which the protein is able to fold, formed by a process referred to as "nucleation condensation" where the structure begins to collapse onto the nucleus.
Modeling of protein folding
De novo or ab initio techniques for computational protein structure prediction can be used for simulating various aspects of protein folding. Molecular dynamics (MD) was used in simulations of protein folding and dynamics in silico. First equilibrium folding simulations were done using implicit solvent model and umbrella sampling. Because of computational cost, ab initio MD folding simulations with explicit water are limited to peptides and small proteins. MD simulations of larger proteins remain restricted to dynamics of the experimental structure or its high-temperature unfolding. Long-time folding processes (beyond about 1 millisecond), like folding of larger proteins (>150 residues) can be accessed using coarse-grained models.
Several large-scale computational projects, such as Rosetta@home, Folding@home and Foldit, target protein folding.
Long continuous-trajectory simulations have been performed on Anton, a massively parallel supercomputer designed and built around custom ASICs and interconnects by D. E. Shaw Research. The longest published result of a simulation performed using Anton as of 2011 was a 2.936 millisecond simulation of NTL9 at 355 K. Such simulations are currently able to unfold and refold small proteins (<150 amino acids residues) in equilibrium and predict how mutations affect folding kinetics and stability.
In 2020 a team of researchers that used AlphaFold, an artificial intelligence (AI) protein structure prediction program developed by DeepMind placed first in CASP, a long-standing structure prediction contest. The team achieved a level of accuracy much higher than any other group. It scored above 90% for around two-thirds of the proteins in CASP's global distance test (GDT), a test that measures the degree of similarity between the structure predicted by a computational program, and the empirical structure determined experimentally in a lab. A score of 100 is considered a complete match, within the distance cutoff used for calculating GDT.
AlphaFold's protein structure prediction results at CASP were described as "transformational" and "astounding". Some researchers noted that the accuracy is not high enough for a third of its predictions, and that it does not reveal the physical mechanism of protein folding for the protein folding problem to be considered solved. Nevertheless, it is considered a significant achievement in computational biology and great progress towards a decades-old grand challenge of biology, predicting the structure of proteins.
See also
Anfinsen's dogma
Chevron plot
Denaturation midpoint
Downhill folding
Folding (chemistry)
Phi value analysis
Potential energy of protein
Protein dynamics
Protein misfolding cyclic amplification
Protein structure prediction software
Proteopathy
Time-resolved mass spectrometry
References
External links
Human Proteome Folding Project
Biochemical reactions
Protein structure | Protein folding | Chemistry,Biology | 7,285 |
72,098,316 | https://en.wikipedia.org/wiki/Ts8 | Ts8 (also known as: TsK2, Tityustoxin K-beta, TsTX-K beta or TsTx-Kβ) is a neurotoxin present in the venom of the Brazilian yellow scorpion, Tityus serrulatus. Ts8 is a selective inhibitor of the voltage-gated potassium channel Kv4.2
Etymology and Source
The neurotoxin Ts8 can be derived from the venom from the Brazilian yellow scorpion, Tityus serrulatus (Ts). This scorpion is predominantly found in Brazil. Alternative names for the Ts8 toxin are TsK2, Tityustoxin K-beta, TsTX-K beta and TsTx-Kβ.
Chemistry
Ts8 belongs to the β-KTx family 1. Toxins in this family contain about 59-75 amino acid residues and three disulfide bridges. There are two-domain peptides; the N-terminal helical domain (NHD) and the C-terminal CSαβ domain (CCD). The CCD is responsible for the neurotoxic activity.
Ts8 contains 60 amino acid residues and the three disulfide bridges that were already mentioned. It has a molecular weight of 6716 Da. Its amino acid sequence is as follows:
K-L-V-A-L-I-P-N-D-Q-L-R-S-I-L-K-A-V-V-H-K-V-A-K-T-Q-F-G-C-P-A-Y-E-G-Y-C-N-D-H-C-N-D-I-E-R-K-D-G-E-C-H-G-F-K-C-K-C-A-K-D
Target
Ts8 selectively and reversibly inhibits the voltage-gated potassium channel Kv4.2. Maximal block of the peak current is 65%. Kv4.2 channels are found in a variety of tissues, including high levels in the brain and heart.
Purified recombinant Ts8 was present in three forms, of which Ts8-FragII has a small inhibitory effect on the Kv1.3 channel.
Mode of action
The inhibition caused by the neurotoxin Ts8 on Kv4.2 channels increases with repeated activation of the channel in the presence of the toxin. In addition the channels inactivated more rapidly, suggesting that the toxin has a preference to bind to the inactivated state of the Kv4.2 channels.
Ts8 does not have pore-forming activity.
Toxicity
In mice, Ts8 increases earlier nociception with higher doses. Elimination or inhibition of Kv4.2 channels via intraplantar injections was seen to induce hypersensitivity to mechanical stimuli. Via intrathecal injection this effect was prolonged and a prolongation plateau of mechanical hypersensitivity was observed. Thus Ts8 can enhance sensitivity to tactile- and mechanical stimuli in mice, by inhibition of the Kv4.2 channels. The symptoms caused by Ts8 induce hyperalgesia, intense and persistent pain.
Ts8 is toxic to human erythrocytes type A+ in concentrations above 2.89 μM.
Treatment
A sting by Tityus serrulatus is treated with a scorpion antivenom serum. This serum, Soro antiscorpionico, containing a human antibody fragment, neutralizes most of the entire venomous cocktail of neurotoxins.
Therapeutic use
In a study from Cordeiro et al (2022) they expressed recombinant Ts8 (rTs8) in Pichia pastoris yeast to be able to evaluate the peptide expression under different conditioning. They looked at the native Ts8 and recombinant Ts8, rTs8-FragI and rTs8-FragII. These forms were all evaluated by an antimicrobial assay. This resulted in growth inhibition of P. pastoris. The native form of the toxin had a larger inhibitory effect than the recombinant forms.
The study from Oliveira et al (2022) showed the antimicrobial activity of Ts8. Here they tested the native Ts8 against different types of microorganisms;
Gram-positive bacteria: Micrococcus luteus
Gram-negative bacteria: Escherichia coli
Yeast: Candida albicans
Filamentous fungus: Aspergillus niger
Ts8 had antimicrobial activity for all of these microorganisms. Ts8 has the strongest effect on gram-negative bacteria, and the lowest effect on both the yeast and the filamentous fungus. This testing was an initial screening to be able to expand the spectrum of action of this toxin. As mentioned before, Ts8 can be toxic for human erythrocytes. The concentration of the antimicrobial assay on Escherichia coli is lower than what is toxic for the human erythrocytes, 1.45 μM. Thus it can be concluded that Ts8 potentially can be used as an antibiotic against E. coli.
See also
Tityustoxin
TsIV
References
Neurotoxins
Ion channel toxins
Tityus serrulatus venom toxins | Ts8 | Chemistry | 1,107 |
21,596,932 | https://en.wikipedia.org/wiki/Dystrophin-associated%20protein | A dystrophin-associated protein is a protein that helps to form the connection between intracellular dystrophin and the extracellular basal lamina.
Examples include sarcoglycan and dystroglycan.
References
Human proteins | Dystrophin-associated protein | Chemistry,Biology | 50 |
28,847,711 | https://en.wikipedia.org/wiki/HMGB4 | High mobility group protein B4 is a transcription factor that in humans is encoded by the HMGB4 gene.
See also
High-mobility group
References
Further reading
Transcription factors | HMGB4 | Chemistry,Biology | 35 |
3,342,099 | https://en.wikipedia.org/wiki/Silicone%20rubber | Silicone rubber is an elastomer (rubber-like material) composed of silicone—itself a polymer—containing silicon together with carbon, hydrogen, and oxygen. Silicone rubbers are widely used in industry, and there are multiple formulations. Silicone rubbers are often one- or two-part polymers, and may contain fillers to improve properties or reduce cost.
Silicone rubber is generally non-reactive, stable, and resistant to extreme environments and temperatures from while still maintaining its useful properties. Due to these properties and its ease of manufacturing and shaping, silicone rubber can be found in a wide variety of products, including voltage line insulators; automotive applications; cooking, baking, and food storage products; apparel such as undergarments, sportswear, and footwear; electronics; medical devices and implants; and in home repair and hardware, in products such as silicone sealants.
The term "silicone" is actually a misnomer. The suffix -one is used by chemists to denote a substance with a double-bonded atom of oxygen in its backbone. When first discovered, silicone was erroneously believed to have oxygen atoms bonded in this way. The technically correct term for the various silicone rubbers is polysiloxanes (polydimethylsiloxanes being a large subset), referring to a saturated Si-O backbone.
Curing
In its uncured state, silicone rubber is a highly adhesive gel or liquid. To convert it to a solid, it must be cured, vulcanized, or catalyzed. This is normally carried out in a two-stage process at the point of manufacture into the desired shape, and then in a prolonged post-cure process. It can also be injection molded or 3D printed.
Silicone rubber may be cured by a platinum-catalyzed cure system, a condensation cure system, a peroxide cure system, or an oxime cure system. For the platinum-catalyzed cure system, the curing process can be accelerated by adding heat or pressure.
Platinum-based cure system
In a platinum-based silicone cure system, also called an addition system (because the key reaction-building polymer is an addition reaction), a hydride- and a vinyl-functional siloxane polymer react in the presence of a platinum complex catalyst, creating an ethyl bridge between the two. The reaction has no byproducts. Such silicone rubbers cure quickly, though the rate of or even ability to cure is easily inhibited in the presence of elemental tin, sulfur, and many amine compounds.
Condensation cure system
Condensation curing systems can be one-part or two-part systems. In one-part or RTV (room-temperature vulcanizing) system, a cross-linker exposed to ambient humidity (i.e., water) experiences a hydrolysis step and is left with a hydroxyl or silanol group. The silanol condenses further with another hydrolyzable group on the polymer or cross-linker and continues until the system is fully cured. Such a system will cure on its own at room temperature and (unlike the platinum-based addition cure system) is not easily inhibited by contact with other chemicals, though the process may be affected by contact with some plastics or metals and may not take place at all if placed in contact with already-cured silicone compounds. The crosslinkers used in condensation cure systems are typically alkoxy, acetoxy, ester, enoxy or oxime silanes such as methyl trimethoxy silane for alkoxy-curing systems and methyl triacetoxysilane for acetoxy-curing systems. In many cases an additional condensation catalyst is added to fully cure the RTV system and achieve a tack-free surface. Organotitanate catalysts such as tetraalkoxy titanates or chelated titanates are used in alkoxy-cured systems. Tin catalysts such as dibutyl tin dilaurate (DBTDL) can be used in oxime and acetoxy-cured systems. Acetoxy tin condensation is one of the oldest cure chemistries used for curing silicone rubber, and is the one used in household bathroom caulk. Depending on the type of detached molecule, it is possible to classify silicone systems as acidic, neutral or alkaline.
Two-part condensation systems package the cross-linker and condensation catalyst together in one part while the polymer and any fillers or pigments are in the second part. Mixing of the two parts causes the curing to take place. A typical filler is fumed silica, also known as pyrogenic silica, which used to control the flow properties of the sealant.
Once fully cured, condensation systems are effective as sealants and caulks in plumbing and building construction and as molds for casting polyurethane, epoxy and polyester resins, waxes, gypsum, and low-melting-temperature metals such as lead. They are typically very flexible and have a high tear strength. They do not require the use of a release agent since silicones have non-stick properties.
Peroxide cure system
Peroxide curing is widely used for curing silicone rubber. The curing process leaves behind byproducts, which can be an issue in food contact and medical applications. However, these products are usually treated in a postcure oven which greatly reduces the peroxide breakdown product content. One of the two main organic peroxides used, dicumyl peroxide, has principal breakdown products of acetophenone and 2-phenyl-2-propanol. The other is 2,4-dichlorobenzoyl peroxide, whose principal breakdown products are 2,4-dichlorobenzoic acid and 1,3-dichlorobenzene.
History
The first silicone elastomers were developed in the search for better insulating materials for electric motors and generators. Resin-impregnated glass fibers were the state-of-the-art materials at the time. The glass was very heat resistant, but the phenolic resins would not withstand the higher temperatures that were being encountered in new smaller electric motors. Building on the work of Frederic Kipping, chemists at Corning Glass and General Electric were investigating heat-resistant materials for use as resinous binders when they synthesized the first silicone polymers, demonstrated that they worked well and found a route to produce them commercially.
Corning Glass in a joint venture with Dow Chemical formed Dow Corning in 1943 to produce this new class of materials. War-time uses included gaskets for the B29's superchargers and supporting Searchlight lenses.
As the unique properties of the new silicone products were studied in more detail, their potential for broader usage was envisioned, and GE opened its own plant to produce silicones in 1947. GE Silicones was sold to Momentive Performance Materials in 2006. Wacker Chemie also started production of silicones in Europe in 1947. The Japanese company Shin-Etsu Chemical began mass production of silicone in 1953.
Properties
Silicone rubber offers good resistance to extreme temperatures, being able to operate normally from . Silicone rubber has low tensile strength, poor wear and tear properties. Some properties such as elongation, creep, cyclic flexing, tear strength, compression set, dielectric strength (at high voltage), thermal conductivity, fire resistance and in some cases tensile strength can be—at extreme temperatures—far superior to organic rubbers in general, although a few of these properties are still lower than for some specialty materials. Silicone rubber is a material of choice in industry when retention of initial shape and mechanical strength are desired under heavy thermal stress or sub-zero temperatures.
Compared to organic rubber
Organic rubber has a carbon-to-carbon backbone which can leave it susceptible to ozone, UV, heat and other aging factors that silicone rubber can withstand well. This makes silicone rubber one of the elastomers of choice in many extreme environments. Silicone is considerably more permeable to gasses than most other rubbers which limits its use in some areas.
Silicone rubber is highly inert, does not react with most chemicals, and is not available to participate in biological processes, allowing it to be used in many medical applications including medical implants.
It is biocompatible, hypoallergenic, which makes it suitable for baby care products, and food contact in general.
Silicone rubber is a reliable solution (as opposed to rubber and thermoplastic elastomers) for migration or interaction problems between the main active ingredients. Its chemical stability prevents it from affecting any substrate it is in contact with (skin, water, blood, active ingredients, etc.).
{| class="wikitable"
!Property
!Value
|-
|Appearance
|
|-
|Hardness, Shore A
|25–90
|-
|Tensile failure stress, ultimate
|
|-
|Elongation after fracture in %
|≥ 700% maximum
|-
|Density
|Can be compounded from 0.95 to over 1.20 g/cm3
|}
Production
To make silicone, the silicon atoms must be isolated from the silicon dioxide compound silica. This is done by heating large volumes of quartz sand to extremely high temperatures, often up to 1800 °C. From here, there are several processes where silicon is combined with methyl chloride and heated. It is then distilled into a polymerised siloxane known as polydimethylsiloxane. The polydimethylsiloxane can then be polymerised. This is done using a variety of techniques depending on the use of the final product. The raw silicone compound is combined with any desired additives, which may include pigments, and the catalyst. It is then injection moulded, extruded or 3D printed. Curing is the final stage in the production process.
Structure
Polysiloxanes differ from other polymers in that their backbones consist of Si–O–Si units instead of C–C units. The large bond angles and bond lengths make polysiloxanes more flexible than basic polymers such as polyethylene. A C–C backbone unit has a bond length of 1.54 Å and a bond angle of 112°, whereas an Si–O backbone unit has a bond length of 1.63 Å and a bond angle of 130°. Polymer segments in polysiloxanes can move farther and change conformation easily, making for a flexible material. Polysiloxanes tend to be more stable and less chemically active because more energy is required to break the silicon-oxygen bond. Although silicon is a congener of carbon, having the same electron bonding configuration, silicon analogues of carbonaceous compounds generally exhibit different properties. The difference in total charge and mass between carbon with 6 protons and 6 neutrons, and silicon with 14 protons and 14 neutrons causes an added layer of electrons and their screening effect changes the electronegativity between the two elements. For example the silicon-oxygen bond in polysiloxanes is significantly more stable than the carbon-oxygen bond in polyoxymethylene, a structurally similar polymer. The difference is partly due to the higher bond energy, the energy required to break the Si-O bond, and also because polyoxymethylene decomposes formaldehyde, which is volatile and escapes driving decomposition forward, but Si-containing decomposition products of silicone are less volatile.
{| class="infobox"
|-
! Mechanical properties
| (Polymax 2005)
|-
| Hardness, shore A
| 10–90
|-
| Tensile strength
| 11 N/mm2
|-
| Elongation at break
| 100–1100 %
|-
| Maximum temperature
| 300 °C
|-
| Minimum temperature
| −120 °C
|}
Special grades
There are many special grades and forms of silicone rubber, including: steam resistant, metal detectable, high tear strength, extreme high temperature, extreme low temperature, electrically conductive, chemical/oil/acid/gas resistant, low smoke emitting, and flame-retardant. A variety of fillers can be used in silicone rubber, although most are non-reinforcing and lower the tensile strength.
Silicone rubber is available in a range of hardness levels, expressed as Shore A or IRHD between 10 and 100, the higher number being the harder compound. It is also available in virtually any colour, and can be colour matched.
Applications
Silicone rubber is used in automotive applications, many cooking, baking, and food storage products, apparel including undergarments, sportswear, and footwear, electronics, to home repair and hardware, and a host of unseen applications. It is usually processed and shaped with the following methods.
Extrusion
Once mixed and coloured, silicone rubber can be extruded into tubes, strips, solid cord or custom profiles according to the size specifications of the manufacturer. Cord can be joined to make O-rings and extruded profiles can be joined to make seals.
Injection moulding
Silicone rubber can be moulded into custom shapes and designs. Manufacturers work to set industry tolerances when extruding, cutting or joining silicone rubber profiles. In the UK this is BS 3734, for extrusions the tightest level is E1 and the widest is E3.
3D printing
Silicone rubber can be 3d printed (liquid deposition modelling LDM) using pump-nozzle extrusion systems. Unfortunately, standard silicone formulations are optimized to be used by extrusion and injection moulding machines and are not applicable in LDM-based 3D printing. The rheological behavior and the pot life need to be adjusted.
3D printing also requires the use of a removable support material that is compatible with the silicone rubber.
Liquid silicone rubber is also manufactured for life science applications (syringe pistons, closure for dispensing system, gaskets for IV flow regulator, respiratory masks, implantable chambers for IV administration), cosmetic products (Mascara brush, make-up packaging, make-up applicator and lipstick moulds) and optics products (circular lens, collimators, Fresnel lenses and free form lenses).Freeze-tolerant solar water-heating panels exploit the elasticity of silicone to repeatedly accommodate the expansion of water on freezing, while its extreme temperature tolerance maintain a lack of brittleness below freezing and excellent tolerance of temperatures in excess of . Its property of not having a carbon backbone, but a chemically robust silicon backbone instead, reduces its potential as a food source for dangerous waterborne bacteria such as Legionella.
Non-dyed silicone rubber tape with an iron(III) oxide additive (making the tape a red-orange colour) is used extensively in aviation and aerospace wiring applications as a splice or wrapping tape due to its non-flammable nature. The iron oxide additive adds high thermal conductivity but does not change the high electrical insulation property of the silicone rubber. This type of self-amalgamating tape amalgamates or fuses to itself, so that when stretched and wrapped around cables, electrical joints, hoses and pipes it bonds into a strong seamless rubbery electrically insulating and waterproof layer, although not adhesive.
As an electrical insulator, silicone rubber has the added virtue of remaining non-conductive when damaged by heat, reducing the likelihood of runaway arcing.
With the addition of carbon or another conductive substance as a powdered filler, silicone rubber can be made electrically conductive while retaining most of its other mechanical properties. As such it is used for flexible contacts which close on being pressed, used in many devices such as computer keyboards and remote control handsets.
Electrical insulation
Silicone rubber is used as an electrical insulator in power cables and cable joints. Silicone-insulated cables are advantageous in that they can withstand temperatures from -90°C to 200°C, and are highly flexible. These properties make them suitable for maintaining circuit integrity in the event of a fire.
Self-healing
In 2007, silicone rubber formed the matrix of the first autonomic self-healing elastomer. The microcapsule-based material was capable of recovering almost all of the original tear strength. Additionally, this material had improved fatigue properties as evaluated using a torsion-fatigue test.
See also
Injection molding of liquid silicone rubber
Forensic engineering
Forensic polymer engineering
Medical grade silicone
RTV silicone
References
Further reading
Brydson, John (1999) Plastics Materials, Butterworth, 9th Ed
Lewis, PR, Reynolds, K and Gagg, C (2004) Forensic Materials Engineering: Case Studies, CRC Press
Elastomers
Sculpture materials
de:Silikone#Silikonkautschuk
zh:硅橡胶 | Silicone rubber | Chemistry | 3,518 |
140,857 | https://en.wikipedia.org/wiki/Electron%E2%80%93positron%20annihilation | Electron–positron annihilation occurs when an electron () and a positron (, the electron's antiparticle) collide. At low energies, the result of the collision is the annihilation of the electron and positron, and the creation of energetic photons:
+ → +
At high energies, other particles, such as B mesons or the W and Z bosons, can be created. All processes must satisfy a number of conservation laws, including:
Conservation of electric charge. The net charge before and after is zero.
Conservation of linear momentum and total energy. This forbids the creation of a single photon. However, in quantum field theory this process is allowed; see examples of annihilation.
Conservation of angular momentum.
Conservation of total (i.e. net) lepton number, which is the number of leptons (such as the electron) minus the number of antileptons (such as the positron); this can be described as a conservation of (net) matter law.
As with any two charged objects, electrons and positrons may also interact with each other without annihilating, in general by elastic scattering.
Low-energy case
There are only a very limited set of possibilities for the final state. The most probable is the creation of two or more gamma photons. Conservation of energy and linear momentum forbid the creation of only one photon. (An exception to this rule can occur for tightly bound atomic electrons.) In the most common case, two gamma photons are created, each with energy equal to the rest energy of the electron or positron (). A convenient frame of reference is that in which the system has no net linear momentum before the annihilation; thus, after collision, the gamma photons are emitted in opposite directions. It is also common for three to be created, since in some angular momentum states, this is necessary to conserve charge parity. It is also possible to create any larger number of photons, but the probability becomes lower with each additional gamma photon because these more complex processes have lower probability amplitudes.
Since neutrinos also have a smaller mass than electrons, it is also possible – but exceedingly unlikely – for the annihilation to produce one or more neutrino–antineutrino pairs. The probability for such process is on the order of 10000 times less likely than the annihilation into photons. The same would be true for any other particles, which are as light, as long as they share at least one fundamental interaction with electrons and no conservation laws forbid it. However, no other such particles are known.
High-energy case
If either the electron or positron, or both, have appreciable kinetic energies, other heavier particles can also be produced (such as D mesons or B mesons), since there is enough kinetic energy in the relative velocities to provide the rest energies of those particles. Alternatively, it is possible to produce photons and other light particles, but they will emerge with higher kinetic energies.
At energies near and beyond the mass of the carriers of the weak force, the W and Z bosons, the strength of the weak force becomes comparable to the electromagnetic force. As a result, it becomes much easier to produce particles such as neutrinos that interact only weakly with other matter.
The heaviest particle pairs yet produced by electron–positron annihilation in particle accelerators are – pairs (mass 80.385 GeV/c2 × 2). The heaviest single-charged particle is the Z boson (mass 91.188 GeV/c2). The driving motivation for constructing the International Linear Collider is to produce the Higgs bosons (mass 125.09 GeV/c2) in this way.
Practical uses
The electron–positron annihilation process is the physical phenomenon relied on as the basis of positron emission tomography (PET) and positron annihilation spectroscopy (PAS). It is also used as a method of measuring the Fermi surface and band structure in metals by a technique called Angular Correlation of Electron Positron Annihilation Radiation.
It is also used for nuclear transition.
Positron annihilation spectroscopy is also used for the study of crystallographic defects in metals and semiconductors;
it is considered the only direct probe for vacancy-type defects.
Reverse reaction
The reverse reaction, electron–positron creation, is a form of pair production governed by two-photon physics.
See also
Bhabha scattering
List of particles
Meitner–Hupfeld effect
Pair production
Positronium
References
Nuclear medicine
Antimatter
Positron | Electron–positron annihilation | Physics,Chemistry | 964 |
3,108,880 | https://en.wikipedia.org/wiki/User%E2%80%93network%20interface | In telecommunications, a user–network interface (UNI) is a demarcation point between the responsibility of the service provider and the responsibility of the subscriber. This is distinct from a network-to-network interface (NNI) that defines a similar interface between provider networks.
Specifications defining a UNI
Metro Ethernet Forum
The Metro Ethernet Forum's Metro Ethernet Network UNI specification defines a bidirectional Ethernet reference point for Ethernet service delivery.
Optical Internetworking Forum
The Optical Internetworking Forum defines a UNI software interface for user systems to request a network connection from an ASON/GMPLS control plane.
See also
Network termination
External links
Metro Ethernet Forum
Network management | User–network interface | Engineering | 139 |
46,791,410 | https://en.wikipedia.org/wiki/Awwwards | Awwwards (Awwwards Online SL) is an organization that hosts web design competitions and conferences across Europe and the United States. Website owners and developers can participate by submitting their websites for review. Submissions are assessed by a jury, and top entries are presented and awarded prizes on a rotational basis.
Nomination process
Web designers submit their websites through Awwwards' platform for consideration for the Site of the Day. A jury, composed of industry professionals, and the Awwwards community evaluate the entries. The best daily sites are published annually in "The 365 Best Websites Around the World" book.
Jury
The jury consists of international designers, developers, and agencies who assess the creativity, technical skills, and insight of the submitted web projects. The panel's expertise ensures a comprehensive review process.
Developer Award
Awwwards, in partnership with Microsoft, created the Developer Award to recognize web developers who demonstrate excellence in creating websites that meet modern standards. The award highlights websites that work seamlessly across various platforms and devices, using best practices in HTML5, JavaScript, and CSS.
Annual winners
Some prominent Site of the Year winners include Mercedes-Benz, Bloomberg L.P., Bose Corporation, Warner Brothers, Volkswagen, Uber, and Google.
Awwwards conference
Awwwards also organizes two-day conferences featuring speakers from major tech companies and industry leaders such as Microsoft, Google, Spotify, Adobe, Opera, and Smashing Magazine. These events focus on the latest trends in web design and development.
See also
Favourite Web Awards
Webby Awards
List of Web Awards
References
Web awards
Web development
Awards established in 2009 | Awwwards | Engineering | 332 |
16,866,655 | https://en.wikipedia.org/wiki/Cobalt%28II%29%20bromide | Cobalt(II) bromide (CoBr2) is an inorganic compound. In its anhydrous form, it is a green solid that is soluble in water, used primarily as a catalyst in some processes.
Properties
When anhydrous, cobalt(II) bromide appears as green crystals. It is hygroscopic and eventually forms the hexahydrate in air, which appears as red-purple crystals. The hexahydrate loses four water of crystallization molecules at 100 °C forming the dihydrate:
CoBr2·6H2O → CoBr2·2H2O + 4 H2O
Further heating to 130 °C produces the anhydrous form:
CoBr2·2H2O → CoBr2 + 2 H2O
The anhydrous form melts at 678 °C. At higher temperatures, cobalt(II) bromide reacts with oxygen, forming cobalt(II,III) oxide and bromine vapor.
The tetrahydrate is molecular, with the formula trans-[CoBr2(H2O)4].
Preparation and reactions
Cobalt(II) bromide can be prepared as a hydrate by the reaction of cobalt hydroxide with hydrobromic acid:
Co(OH)2 + 2HBr → CoBr2·6H2O
The classical coordination compound bromopentaamminecobalt(III) bromide is prepared by oxidation of an aqueous solution of cobalt(II) bromide and ammonia.
2 CoBr2 + 8 NH3 + 2 NH4Br + H2O2 → 2 [Co(NH3)5Br]Br2 + 2 H2O
Triphenylphosphine complexes of cobalt(II) bromide have been used as a catalysts in organic synthesis.
Safety
Exposure to large amounts of cobalt(II) can cause cobalt poisoning. Bromide is also mildly toxic.
References
Cobalt(II) compounds
Bromides
Metal halides | Cobalt(II) bromide | Chemistry | 412 |
1,884 | https://en.wikipedia.org/wiki/ASCII%20art | ASCII art is a graphic design technique that uses computers for presentation and consists of pictures pieced together from the 95 printable (from a total of 128) characters defined by the ASCII Standard from 1963 and ASCII compliant character sets with proprietary extended characters (beyond the 128 characters of standard 7-bit ASCII). The term is also loosely used to refer to text-based visual art in general. ASCII art can be created with any text editor, and is often used with free-form languages. Most examples of ASCII art require a fixed-width font (non-proportional fonts, as on a traditional typewriter) such as Courier or Consolas for presentation.
Among the oldest known examples of ASCII art are the
creations by computer-art pioneer Kenneth Knowlton from around 1966, who was working for Bell Labs at the time. "Studies in Perception I" by Knowlton and Leon Harmon from 1966 shows some examples of their early ASCII art.
ASCII art was invented, in large part, because early printers often lacked graphics ability and thus, characters were used in place of graphic marks. Also, to mark divisions between different print jobs from different users, bulk printers often used ASCII art to print large banner pages, making the division easier to spot so that the results could be more easily separated by a computer operator or clerk. ASCII art was also used in early e-mail when images could not be embedded.
History
Typewriter art
Since 1867, typewriters have been used for creating visual art. Typists could find guides in books or magazines with instructions on how to type portraits or other depictions.
TTY and RTTY
TTY stands for "TeleTYpe" or "TeleTYpewriter", and is also known as Teleprinter or Teletype.
RTTY stands for Radioteletype; character sets such as Baudot code, which predated ASCII, were used. According to a chapter in the "RTTY Handbook", text images have been sent via teletypewriter as early as 1923. However, none of the "old" RTTY art has been discovered yet. What is known is that text images appeared frequently on radioteletype in the 1960s and the 1970s.
Line-printer art
In the 1960s, Andries van Dam published a representation of an electronic circuit produced on an IBM 1403 line printer. At the same time, Kenneth Knowlton was producing realistic images, also on line printers, by overprinting several characters on top of one another.
Note that it was not ASCII art in a sense that the 1403 was driven by an EBCDIC-coded platform and the character sets and trains available on the 1403 were derived from EBCDIC rather than ASCII, despite some glyphs commonalities.
ASCII art
The widespread usage of ASCII art can be traced to the computer bulletin board systems of the late 1970s and early 1980s. The limitations of computers of that time period necessitated the use of text characters to represent images. Along with ASCII's use in communication, however, it also began to appear in the underground online art groups of the period.
An ASCII comic is a form of webcomic which uses ASCII text to create images. In place of images in a regular comic, ASCII art is used, with the text or dialog usually placed underneath.
During the 1990s, graphical browsing and variable-width fonts became increasingly popular, leading to a decline in ASCII art. Despite this, ASCII art continued to survive through online MUDs, an acronym for "Multi-User Dungeon", (which are textual multiplayer role-playing video games), Internet Relay Chat, Email, message boards, and other forms of online communication which commonly employ the needed fixed-width.
ASCII art is seen to this day on the CLI app Neofetch, which displays the logo of the OS on which it is invoked.
ANSI
ASCII and more importantly, ANSI were staples of the early technological era; terminal systems relied on coherent presentation using color and control signals standard in the terminal protocols.
Over the years, warez groups began to enter the ASCII art scene. Warez groups usually release .nfo files with their software, cracks or other general software reverse-engineering releases. The ASCII art will usually include the warez group's name and maybe some ASCII borders on the outsides of the release notes, etc.
BBS systems were based on ASCII and ANSI art, as were most DOS and similar console applications, and the precursor to AOL.
Uses
ASCII art is used wherever text can be more readily printed or transmitted than graphics, or in some cases, where the transmission of pictures is not possible. This includes typewriters, teleprinters, non-graphic computer terminals, printer separators, in early computer networking (e.g., BBSes), email, and Usenet news messages. ASCII art is also used within the source code of computer programs for representation of company or product logos, and flow control or other diagrams. In some cases, the entire source code of a program is a piece of ASCII art – for instance, an entry to one of the earlier International Obfuscated C Code Contest is a program that adds numbers, but visually looks like a binary adder drawn in logic ports.
Some electronic schematic archives represent the circuits using ASCII art.
Examples of ASCII-style art predating the modern computer era can be found in the June 1939, July 1948 and October 1948 editions of Popular Mechanics.
Early computer games played on terminals frequently used ASCII art to simulate graphics, most notably the roguelike genre using ASCII art to visually represent dungeons and monsters within them. "0verkill" is a 2D platform multiplayer shooter game designed entirely in color ASCII art. MPlayer and VLC media player can display videos as ASCII art through the AAlib library. ASCII art is used in the making of DOS-based ZZT games.
Many game walkthrough guides come as part of a basic .txt file; this file often contains the name of the game in ASCII art. Such as below, word art is created using backslashes and other ASCII values in order to create the illusion of 3D.
Types and styles
Different techniques could be used in ASCII art to obtain different artistic effects.
"Typewriter-style" lettering, made from individual letter characters:
Line art, for creating shapes:
.--. /\
'--' /__\ (^._.^)~ <(o.o )>
Solid art, for creating filled objects:
.g@8g. db
'Y8@P' d88b
Shading, using symbols with various intensities for creating gradients or contrasts:
:$#$: "4b. ':.
:$#$: "4b. ':.
Combinations of the above, often used as signatures, for example, at the end of an email:
|\_/| **************************** (\_/)
/ @ @ \ * "Purrrfectly pleasant" * (='.'=)
( > º < ) * Poppy Prinz * (")_(")
`>>x<<´ * (pprinz@example.com) *
/ O \ ****************************
As-pixel characters use combinations of ░ , █ , ▄, ▀ (Block Elements), and/or ⣿, ⣴, ⢁, etc (Braille ASCII) to make pictures:
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠿⠿⠿⠿⢿⣿⣿⣿⣿⣿⣿
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠟⢁⣴⣾⣿⣷⣦⣌⠙⢿⣿⣿⣿
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠟⢁⣴⣿⣿⣿⣿⣿⣿⣿⣷⡈⢻⣿⣿
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠟⢁⣴⣿⣿⠟⠋⣉⠙⢻⣿⣿⣿⣷⠀⣿⣿
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⠟⢁⣴⣿⣿⠟⢁⣴⣿⣿⡷⢀⣿⣿⣿⡿⠀⣿⣿
⣿⣿⣿⣿⣿⣿⣿⣿⣿⠟⢁⣴⣿⣿⠟⢁⣴⣿⣿⡿⠋⣠⣾⣿⣿⠟⢁⣼⣿⣿
⣿⣿⣿⣿⣿⣿⣿⠟⢁⣴⣿⣿⠟⢁⣴⣿⣿⡿⠋⣠⣾⣿⣿⠟⢁⣴⣿⣿⣿⣿
⣿⣿⣿⣿⣿⠟⢁⣴⣿⣿⠟⢁⣴⣿⣿⡿⠋⣠⣾⣿⣿⠟⢁⣴⣿⣿⣿⣿⣿⣿
⣿⣿⣿⠟⢁⣴⣿⣿⣿⣿⣶⣿⣿⡿⠋⣠⣾⣿⣿⠟⢁⣴⣿⣿⣿⣿⣿⣿⣿⣿
⣿⣿⠁⣴⣿⣿⣿⣿⣿⣿⣿⡿⠋⣠⣾⣿⣿⠟⢁⣴⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿
⣿⣿⠀⢿⣿⣿⣿⣿⣿⡿⠋⣠⣾⣿⣿⠟⢁⣴⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿
⣿⣿⣧⡈⠻⢿⣿⡿⠋⣠⣾⣿⣿⡟⢁⣴⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿
⣿⣿⣿⣿⣷⣶⣶⣶⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿
Emoticons
The simplest forms of ASCII art are combinations of two or three characters for expressing emotion in text. They are commonly referred to as 'emoticon', 'smilie', or 'smiley'. There is another type of one-line ASCII art that does not require the mental rotation of pictures, which is widely known in Japan as kaomoji (literally "face characters".)
More complex examples use several lines of text to draw large symbols or more complex figures. Hundreds of different text smileys have developed over time, but only a few are generally accepted, used and understood.
ASCII comic
An ASCII comic is a form of webcomic.
The Adventures of Nerd Boy
The Adventures of Nerd Boy, or just Nerd Boy, was an ASCII comic, published by Joaquim Gândara between 5 August 2001 and 17 July 2007, and consisting of 600 strips. They were posted to ASCII art newsgroup alt.ascii-art and on the website. Some strips have been translated to Polish and French.
Styles of the computer underground text art scene
Atari 400/800 ATASCII
The Atari 400/800, which were released in 1979, did not follow the ASCII standard and had their own character set, called ATASCII. The emergence of ATASCII art coincided with the growing popularity of BBS Systems caused by availability of the acoustic couplers that were compatible with the 8-bit home computers. ATASCII text animations are also referred to as "break animations" by the Atari sceners.
C-64 PETSCII
The Commodore 64, which was released in 1982, also did not follow the ASCII standard. The C-64 character set is called PETSCII, an extended form of ASCII-1963. As with the Atari's ATASCII art, C-64 fans developed a similar scene that used PETSCII for their creations.
"Block ASCII" / "High ASCII" style ASCII art on the IBM PC
So-called "block ASCII" or "high ASCII" uses the extended characters of the 8-bit code page 437, which is a proprietary standard introduced by IBM in 1979 (ANSI Standard x3.16) for the IBM PC DOS and MS-DOS operating systems. "Block ASCIIs" were widely used on the PC during the 1990s until the Internet replaced BBSes as the main communication platform. Until then, "block ASCIIs" dominated the PC Text Art Scene.
The first art scene group that focused on the extended character set of the PC in their artwork was called "Aces of ANSI Art", or . Some members left in 1990 and formed a group called "ANSI Creators in Demand", or ACiD. In that same year the second major underground art scene group "Insane Creators Enterprise", or ICE, was founded.
There is some debate between ASCII and block ASCII artists, with "Hardcore" ASCII artists maintaining that block ASCII art is in fact not ASCII art, because it does not use the 128 characters of the original ASCII standard. On the other hand, block ASCII artists argue that if their art uses only characters of the computer's character set, then it is to be called ASCII, regardless if the character set is proprietary or not.
Microsoft Windows does not support the ANSI Standard x3.16. One can view block ASCIIs with a text editor using the font "Terminal", but it will not look exactly as it was intended by the artist. With a special ASCII/ANSI viewer, such as ACiDView for Windows , one can see block ASCII and ANSI files properly. An example that illustrates the difference in appearance is part of this article. Alternatively, one could look at the file using the TYPE command in the command prompt.
"Amiga"/"Oldskool" style ASCII art
In the art scene one popular ASCII style that used the 7-bit standard ASCII character set was the so-called "Oldskool" style. It is also called "Amiga style", due to its origin and widespread use on Commodore Amiga computers. The style uses primarily the characters _/\-+=.()<>: and looks more like the outlined drawings of shapes than real pictures. The accompanying image is an example of "Amiga style" (also referred to as "old school" or "oldskool" style) scene ASCII art.
The Amiga ASCII scene surfaced in 1992, seven years after the introduction of the Commodore Amiga 1000. The Commodore 64 PETSCII scene did not make the transition to the Commodore Amiga as the C64 demo and warez scenes did. Among the first Amiga ASCII art groups were ART, Epsilon Design, Upper Class, Unreal (later known as "DeZign"). This means that the text art scene on the Amiga was actually younger than the text art scene on the PC. The Amiga artists also did not call their ASCII art style "Oldskool". That term was introduced on the PC; when and by whom is unknown and lost to history.
The Amiga style ASCII artwork was most often released in the form of a single text file, which included all the artwork (usually requested), with some design parts in between, as opposed to the PC art scene where the art work was released as a ZIP archive with separate text files for each piece. Furthermore, the releases were usually called "ASCII collections" and not "art packs" like on the IBM PC.
In text editors
_ ___ _ _
| ___|_ _/ ___| | ___| |_
| |_ | | | _| |/ _ \ __|
| _| | | |_| | | __/ |_
|_| |___\|_|\___|\__|
This kind of ASCII art is handmade in a text editor. Popular editors used to make this kind of ASCII art include Microsoft Notepad, CygnusEditor also known as CED (Amiga), and EditPlus2 (PC).
The accompanying image shows an Oldskool font example done with the ASCII editor FIGlet on a PC.
Newskool style ASCII art
"Newskool" is a popular form of ASCII art which capitalizes on character strings like "$#Xxo". In spite of its name, the style is not "new"; on the contrary, it was very old but fell out of favor and was replaced by "Oldskool" and "Block" style ASCII art. It was dubbed "Newskool" upon its comeback and renewed popularity at the end of the 1990s.
Newskool changed significantly as the result of the introduction of extended proprietary characters. The classic 7-bit standard ASCII characters remain predominant, but the extended characters are often used for "fine tuning" and "tweaking". The style developed further after the introduction and adaptation of Unicode.
Methods for generating ASCII art
While some prefer to use a simple text editor to produce ASCII art, specialized programs, such as JavE have been developed that often simulate the features and tools in bitmap image editors. For Block ASCII art and ANSI art the artist almost always uses a special text editor, because to generate the required characters on a standard keyboard, one needs to know the Alt code for each character. For example, + will produce ▓, + will produce ▒, and + will produce ◘.
The special text editors have sets of special characters assigned to existing keys on the keyboard. Popular DOS-based editors, such as TheDraw and ACiDDraw had multiple sets of different special characters mapped to the function keys to make the use of those characters easier for the artist who can switch between individual sets of characters via basic keyboard shortcuts. PabloDraw is one of the very few special ASCII/ANSI art editors that was developed for Windows.
Image to text conversion
Other programs allow one to automatically convert an image to text characters, which is a special case of vector quantization. A method is to sample the image down to grayscale with less than 8-bit precision, and then assign a character for each value. Such ASCII art generators often allow users to choose the intensity and contrast of the generated image.
Three factors limit the fidelity of the conversion, especially of photographs:
depth (solutions: reduced line spacing; bold style; block elements; colored background; good shading);
sharpness (solutions: a longer text, with a smaller font; a greater set of characters; variable width fonts);
ratio (solutions with compatibility issues: font with a square grid; stylized without extra line spacing).
Examples of converted images are given below.
This is one of the earliest forms of ASCII art, dating back to the early days of the 1960s minicomputers and teletypes. During the 1970s, it was popular in US malls to get a t-shirt with a photograph printed in ASCII art on it from an automated kiosk containing a computer, and London's Science Museum had a similar service to produce printed portraits. With the advent of the web, HTML and CSS, many ASCII conversion programs will now quantize to a full RGB colorspace, enabling colorized ASCII images.
Still images or movies can also be converted to ASCII on various UNIX and UNIX-like systems using the AAlib (black and white) or libcaca (colour) graphics device driver, or the VLC media player or mpv under Windows, Linux or macOS; all of which render the screen using ASCII symbols instead of pixels.
There are also a number of smartphone applications, such as ASCII cam for Android, that generate ASCII art in real-time using input from the phone's camera. These applications typically allow the ASCII art to be saved as either a text file or as an image made up of ASCII text.
Non fixed-width ASCII
Most ASCII art is created using a monospaced font, such as Courier, where all characters are identical in width. Early computers in use when ASCII art came into vogue had monospaced fonts for screen and printer displays. Today, most of the more commonly used fonts in word processors, web browsers and other programs are proportional fonts, such as Helvetica or Times Roman, where different widths are used for different characters. ASCII art drawn for a fixed width font will usually appear distorted, or even unrecognizable when displayed in a proportional font.
Some ASCII artists have produced art for display in proportional fonts. These ASCIIs, rather than using a purely shade-based correspondence, use characters for slopes and borders and use block shading. These ASCIIs generally offer greater precision and attention to detail than fixed-width ASCIIs for a lower character count, although they are not as universally accessible since they are usually relatively font-specific.
Animated ASCII art
Animated ASCII art started in 1970 from so-called VT100 animations produced on VT100 terminals. These animations were simply text with cursor movement instructions, deleting and erasing the characters necessary to appear animated. Usually, they represented a long hand-crafted process undertaken by a single person to tell a story.
Contemporary web browser revitalized animated ASCII art again. It became possible to display animated ASCII art via JavaScript or Java applets. Static ASCII art pictures are loaded and displayed one after another, creating the animation, very similar to how movie projectors unreel film reel and project the individual pictures on the big screen at movie theaters. A new term was born: "ASCIImation" – another name of animated ASCII art. A seminal work in this arena is the Star Wars ASCIImation. More complicated routines in JavaScript generate more elaborate ASCIImations showing effects like Morphing effects, star field emulations, fading effects and calculated images, such as mandelbrot fractal animations.
There are now many tools and programs that can transform raster images into text symbols; some of these tools can operate on streaming video. For example, the music video for American singer Beck's song "Black Tambourine" is made up entirely of ASCII characters that approximate the original footage. VLC, a media player software, can render any video in colored ASCII through the libcaca module.
Other text-based visual art
There are a variety of other types of art using text symbols from character sets other than ASCII and/or some form of color coding. Despite not being pure ASCII, these are still often referred to as "ASCII art". The character set portion designed specifically for drawing is known as the line drawing characters or pseudo-graphics.
ANSI art
The IBM PC graphics hardware in text mode uses 16 bits per character. It supports a variety of configurations, but in its default mode under DOS they are used to give 256 glyphs from one of the IBM PC code pages (Code page 437 by default), 16 foreground colors, eight background colors, and a flash option. Such art can be loaded into screen memory directly. ANSI.SYS, if loaded, also allows such art to be placed on screen by outputting escape sequences that indicate movements of the screen cursor and color/flash changes. If this method is used then the art becomes known as ANSI art. The IBM PC code pages also include characters intended for simple drawing which often made this art appear much cleaner than that made with more traditional character sets. Plain text files are also seen with these characters, though they have become far less common since Windows GUI text editors (using the Windows ANSI code page) have largely replaced DOS-based ones.
Shift_JIS and Japan
In Japan, ASCII art (AA) is mainly known as Shift_JIS art. Shift JIS offers a larger selection of characters than plain ASCII (including characters from Japanese scripts and fullwidth forms of ASCII characters), and may be used for text-based art on Japanese websites.
Often, such artwork is designed to be viewed with the default Japanese font on a platform, such as the proportional MS P Gothic.
Kaomoji
Users on ASCII-NET, in which the word ASCII refers to the ASCII Corporation rather than the American Standard Code for Information Interchange, popularised a style of in which the face appears upright rather than rotated.
Unicode
Unicode would seem to offer the ultimate flexibility in producing text based art with its huge variety of characters. However, finding a suitable fixed-width font is likely to be difficult if a significant subset of Unicode is desired. (Modern UNIX-style operating systems do provide complete fixed-width Unicode fonts, e.g. for xterm. Windows has the Courier New font, which includes characters like ♥☺). Also, the common practice of rendering Unicode with a mixture of variable width fonts is likely to make predictable display hard, if more than a tiny subset of Unicode is used. is an adequate representation of a cat's face in a font with varying character widths.
Control and combining characters
The combining characters mechanism of Unicode provides considerable ways of customizing the style, even obfuscating the text (e.g. via an online generator like Obfuscator, which focuses on the filters). Glitcher is one example of Unicode art, initiated in 2012: These symbols, intruding up and down, are made by combining lots of diacritical marks. It’s a kind of art. There’s quite a lot of artists who use the Internet or specific social networks as their canvas. The corresponding creations are favored in web browsers (thanks to their always better support), as geekily stylized usernames for social networks. With a fair compatibility, and among different online tools, [Facebook symbols] showcases various types of Unicode art, mainly for aesthetic purpose (Ɯıḳĭƥḙȡḯả Wîkipêȡıẚ Ẉǐḳîṗȅḍȉā Ẃįḵįṗẻḑìẵ Ẉĭḵɪṕḗdïą Ẇïƙỉpểɗĭà Ẅȉḱïṕȩđĩẵ etc.). Besides, the creations can be hand-crafted (by programming), or pasted from mobile applications (e.g. the category of 'fancy text' tools on Android). The underlying technique dates back to the old systems that incorporated control characters, though. E.g. the German composite ö would be imitated on ZX Spectrum by overwriting " after backspace and o.
Overprinting (surprint)
In the 1970s and early 1980s it was popular to produce a kind of text art that relied on overprinting. This could be produced either on a screen or on a printer by typing a character, backing up, and then typing another character, just as on a typewriter. This developed into sophisticated graphics in some cases, such as the PLATO system (circa 1973), where superscript and subscript allowed a wide variety of graphic effects. A common use was for emoticons, with WOBTAX and VICTORY both producing convincing smiley faces. Overprinting had previously been used on typewriters, but the low-resolution pixelation of characters on video terminals meant that overprinting here produced seamless pixel graphics, rather than visibly overstruck combinations of letters on paper.
Beyond pixel graphics, this was also used for printing photographs, as the overall darkness of a particular character space dependent on how many characters, as well as the choice of character, were printed in a particular place. Thanks to the increased granularity of tone, photographs were often converted to this type of printout. Even manual typewriters or daisy wheel printers could be used. The technique has fallen from popularity since all cheap printers can easily print photographs, and a normal text file (or an e-mail message or Usenet posting) cannot represent overprinted text. However, something similar has emerged to replace it: shaded or colored ASCII art, using ANSI video terminal markup or color codes (such as those found in HTML, IRC, and many internet message boards) to add a bit more tone variation. In this way, it is possible to create ASCII art where the characters only differ in color.
See also
Micrography
Types and styles: Alt code, ASCII stereogram, box-drawing characters, emoticon, FILE_ID.DIZ, .nfo (release info file)
Pre-ASCII history: Calligram, Concrete poetry, Typewriter, Typewriter mystery game, Teleprinter, Radioteletype
Related art: ANSI art, ASCII porn, ATASCII, Fax art, PETSCII, Shift JIS art, Text semigraphics
Related context: Bulletin board system (BBS), Computer art scene, :Category:Artscene groups
Software: AAlib, cowsay
Unicode: Homoglyph, Duplicate characters in Unicode
References
Further reading
(Polish translators: Ania Górecka [ag], Asia Mazur [as], Błażej Kozłowski [bug], Janusz [jp], Łukasz Dąbrowski [luk], Łukasz Tyrała [lt.], Łukasz Wilk [wilu], Marcin Gliński [fsc])
External links
media4u.ch - ASCII Art (ASCII Art Movie. The Matrix in ASCII Art)
TexArt.io ASCII Art collection
Textfiles.com archive
Sixteen Colors ANSI Art and ASCII Art Archive
Defacto2.net Scene NFO Files Archive
Chris.com ASCII art collection
"As-Pixel Characters" ASCII art collection
ASCII Art Animation of Star Wars, "ASCIIMATION"
ASCII Keyboard Art Collection
Animasci
Video to ASCII Demonstration in 4 stages
Computer art
Digital art
New media art
Internet art
Multimedia
Wikipedia articles with ASCII art | ASCII art | Technology | 5,865 |
63,070,805 | https://en.wikipedia.org/wiki/Substances%20poisonous%20to%20dogs | Food products and household items commonly handled by humans can be toxic to dogs. The symptoms can range from simple irritation to digestion issues, behavioral changes, and even death. The categories of common items ingested by dogs include food products, human medication, household detergents, indoor and outdoor toxic plants, and rat poison.
Common signs of dog poisoning and exposure
The symptoms of poisoning vary depending on substance, the quantity a dog has consumed, the breed and size of the mammal. A common list of symptoms are digestion problems, such as vomiting, diarrhea, or blood in stool; bruising and bleeding gums, nose, or inside the ear canal; behavioral changes, such as lethargy, hyperactivity, and seizures; unusual items found in the dog's stool.If left in the vicinity, poisonous items can be swallowed by curious or hungry dogs. Uninformed pet owners have also been found to unintentionally poison their dogs by treating them with human medications or feeding them foods they can't metabolize.
In addition, some plants are toxic to dogs. Poisoning by contact happens most commonly with indoor plants when a dog gets the substance on their coat or muzzle. These can cause skin irritation and burns, but they can also become ingested when grooming.
Inhaled toxins, such as smoke or pesticides, can find their way into a dog's respiratory system and cause difficult breathing. If left untreated, these toxins can make their way to other organs of the body.
Substances
Human food
Many human foods cause serious problems when ingested in large amounts. In 2011, the consumption of toxic foods was the number one cause of poisoning in dogs. In 2017, the ASPCA Animal Poison Control Center received 199,000 poisoning cases, almost one-fifth of which were the result of ingesting human foods.
Avocado
Avocados are known for having high amounts of persin, a chemical toxic to many animals, including dogs. Persin is found in the leaves, bark, pulp, and skin of the avocado, making it harder for dogs to ingest too much. However, high amounts of persin can cause an upset stomach in dogs, and eating large amounts of persin over a longer period of time has been known to cause heart failure in dogs. Large amounts of avocado flesh at once can cause vomiting and an upset stomach, and its high-fat content can cause pancreatitis in dogs.
Chocolate
Chocolate is dangerous for dogs because they are unable to break down theobromine and caffeine, both present in chocolate. Darker chocolate and baking chocolate contain a higher amount of theobromine, thus they are more dangerous than milk chocolate or white chocolate. Small amounts of chocolate may cause vomiting or diarrhea, but larger amounts may affect the heart and brain. Large amounts of chocolate cause the dog to suffer irregular heart rhythms or heart failure.
Chocolate-style dog treats can be made with carob, which is similar to chocolate but innocuous to dogs.
Grapes/raisins/currants
These include any fruit of the Vitis species. It is unclear what substance within these fruits is toxic to dogs. There are several theories: mycotoxin, salicylate, tartaric acid, or potassium bitartrate, are all naturally found in grapes and decrease blood flow to the kidneys. There may be no dose information to show how much is too much. One dog may tolerate grapes or raisins better than another.
Macadamia nuts
Macadamia nuts have been included in the top foods to avoid feeding dogs. Like grapes or raisins, the substance of the nut responsible for negative reactions is unknown. Minuscule amounts of the nut can cause adverse reactions – "as little as 1/10th of an ounce per roughly 2 pounds of body weight." Macadamia nuts are singled out as having higher toxicity. Other nuts in general are high in fat and can cause a dog to become ill.
Xylitol
The U.S. Food and Drug Administration has issued alerts to notify the public that xylitol, a sugar substitute, is harmful to dogs. It is used in sugar-free foods including gum, candy, and oral hygiene products. Some peanut butter will also contain xylitol. Xylitol can cause liver failure and hypoglycemia because it stimulates rapid insulin production in the canine pancreas. Potential symptoms include loss of coordination, vomiting, or seizures. Xylitol is not always clearly labeled on sugar-free foods. Ingredient listings should indicate if xylitol is in the product. Food labels with the listing for "sugar alcohol" may contain xylitol. Other names for xylitol include birch sugar, E967, Meso-Xylitol, Xilitol, Xylit, 1, 2, 3, 4, 5-Pentol, and Sucre de Bouleau.
Fruit pits and seeds
Apples are safe for dogs, but apple seeds are not. Apple seeds, persimmon, peach, and plum pits, as well as other fruit seeds or pits have "cyanogenic glycosides". For example, if an apple seed skin is broken as a dog eats an apple, then cyanide could be released. Apple seeds should be removed before a dog eats the apple.
Onions and garlic
The Alliaceae family, of the Allium genus, or the onion family, includes onion, garlic, shallots, scallions, chives, and leeks. These contain N-propyl disulfide, Allyl propyl disulfide, and sodium N-propylthiosulfate which can cause red blood cell damage and anemia. Thiosulphate poisoning from onions can cause orange to dark-red tinged urine, vomiting, and diarrhea.
Medication
Human vitamin supplements can damage the digestive tract lining, especially those containing iron, and can lead to kidney and liver damage.
Ibuprofen and acetaminophen, commonly known as Motrin or Advil, and Tylenol, can cause liver damage in dogs.
Human antidepressant drugs like Celexa can cause neurological problems in dogs.
ADHD medications contain stimulants, such as methylphenidate, that if ingested even in small amounts can be life-threatening to dogs. Examples are Concerta, Vyvanse, Adderall, and Dexadrine.
Household products
Many cases of pet poisoning in the United States are caused by household products.
Substances with a pH greater than 7 are considered alkalis. Usually, exposure causes some level of irritation. However, these substances generally have no taste or odor which increases the chance of larger amounts being ingested by a dog. At high levels of consumption, alkalis become a greater danger for dogs. Bleach, oven and drain/pipe cleaners, hair relaxers, and lye are examples of alkaline products.
Ethylene glycol, antifreeze, is extremely toxic to dogs. It has a sweet taste and thus dogs will drink it. As little as 2 1/2 tablespoons can kill a medium-sized dog in 2–3 days. This type of poisoning is often fatal as dog owners do not know their pet has ingested the antifreeze. De-icing fluids can also contain ethylene glycol.
Paraquat is used for weeding and grass control. It is so toxic that blue dye is added so it is not confused with coffee, a pungent odor is added as a warning, and a vomiting agent in case it is ingested. In the US, it can only be used by those with a commercial license for its use. It is one of the most commonly used herbicides worldwide. Outside of the US, the licensing requirements may not exist.
Pesticides
Pesticides containing organophosphates can be fatal to dogs. "Disulfoton is an example found in rose care products." "They're considered junior-strength nerve agents because they have the same mechanism of action as nerve gases like sarin", explained Dana Boyd Barr, an exposure scientist at Emory University in Atlanta, Georgia, who has studied organophosphate poisoning. Organophosphates are not banned from use but require licensing for use.
Rodenticides
Zinc phosphide is a common ingredient in rat poison or rodenticide. Zinc phosphide is a combination of phosphorus and zinc. If ingested, the acid in a dog's stomach turns the compound into phosphine, which is a toxic gas. The phosphine gas crosses into the dog's cells and causes the cell to die. Signs of poisoning include vomiting, anxiety, and loss of coordination. If a dog has not eaten and has an empty stomach when ingesting zinc phosphide, signs may not be apparent for up to 12 hours.
Strychnine is another rodenticide that is dangerous and causes similar reactions to zinc phosphide exposure. If a dog survives 24–48 hours after this type of poisoning, they generally recover well.
Veterinary products
Rimadyl, Dermaxx, and Previcox are types of non-steroidal anti-inflammatory drugs specifically for veterinary use for osteoarthritis, inflammation, and pain control in dogs. These can cause liver or kidney issues in dogs.
In most cases, issues of poisoning by veterinary products are due to incorrect administration or dosing by the veterinarian or the dog owner.
Plants
Daffodil
Daffodils contain lycorine which can cause vomiting, drooling, diarrhea, stomachache, heart, and breathing issues. Any part of the plant may induce side effects, but the bulb is the most toxic. At higher amounts, the toxin can cause gastrointestinal problems or a drop in blood pressure.
Tulip
Any part of the tulip can be poisonous but the bulb is the most toxic causing irritation in the mouth and throat. Signs of this type of poisoning are drooling, vomiting, stomachache, and diarrhea.
Azalea
Azaleas contain grayanotoxins. This toxin passes through the dog's body quickly and symptoms of vomiting, diarrhea, stomach pain, weakness, or abnormal heart rate usually subside in a few hours.
Oleander
Oleander contains cardiac glycosides oleandrin and nerioside. When ingested, they can result in fatal heart abnormalities, muscle tremors, incoordination, vomiting, and bloody diarrhea. The signs can start within a few hours and cause a dog's condition to decline quickly, thus treatment is often not successful.
Dieffenbachia
Dieffenbachia causes oral irritation, vomiting, and difficult swallowing in dogs. This plant contains calcium oxalate crystals. After ingestion, a dog may have a hard time swallowing and begin drooling or coughing as if choking. Dieffenbachia can cause damage to the liver and kidneys leading to death, comas, or permanent damage to critical organs, including the liver and kidneys, which may even lead to death.
Sago palm
Sago palms are toxic and potentially fatal to all pets, producing symptoms that include vomiting, diarrhea, seizures, and liver failure. The leaves and bark are both harmful, and the seeds (or "nuts") are even more toxic.
Cyclamen
Possibly all species of cyclamen are toxic to dogs. Cyclamen contains triterpenoid saponins that irritate skin and are toxic to dogs.
Castor bean
Castor beans or the castor oil plant contain ricin which is toxic to dogs. It can be fatal depending on how much of the plant is ingested. The beans of the plant have a higher concentration of ricin and if chewed instead of swallowed whole will cause increased toxicity levels.
Hemlock
The USDA lists water hemlock as “the most violently toxic plant that grows in North America”. Dog deaths due to hemlock poisoning are unusual, and most animal deaths are cows or other grazing animals. If a dog does ingest hemlock, the cicutoxin in the plant can be fatal very quickly as it causes the heart and nervous system to not be able to function normally.
Treatment and prognosis
There are many possible ways to handle a dog, depending on the severity of the issue, but one of the most important parts is timing. A dog that has been exposed to a toxic substance has a better chance of recovery if treatment is initiated quickly. With some things, like plants or detergents, if a dog shows signs of irritation, it may be simply enough to remove them from the dog's vicinity. Thorough washing with soap and water can usually prevent further absorption of poisons on the skin. In other cases, where the poisoning is more severe or the dog has swallowed something, taking it to a veterinarian quickly is vital.
Blood tests will then indicate enzyme levels from the liver and kidneys and bowel functions. They will also show levels of red and white blood cells and platelet levels. Just as in humans, there are established ranges for normal functions in dogs, and blood test results will indicate what may be wrong in a dog's body. Although it is always better if the substance is known right away.
A veterinarian can then determine further steps, such as inducing vomiting to remove that substance. Treatment for any swellings with antihistamines or other inflammatory drugs. In severe cases the dog may be put under anesthesia for their stomach to be flushed or surgery to be performed. if the poisonous substance cannot be physically removed, an activated charcoal solution is given to prevent absorption in the gastrointestinal tract. In the cases of poisons that cause liver damage, intravenous fluids assist in flushing toxins from the dog's body and may be combined with medications to help liver function.
Supportive treatment is often necessary until the poison can be metabolized. The type of support required depends on the animal’s condition and may include controlling seizures, maintaining breathing with a ventilator, controlling heart problems, such as irregular heart beats and treating pain with pain medications. In some cases, there is a known antidote for a specific poison.
References
Dog health
Poisons
Toxins | Substances poisonous to dogs | Environmental_science | 2,958 |
261,460 | https://en.wikipedia.org/wiki/Human%20Development%20Index | The Human Development Index (HDI) is a statistical composite index of life expectancy, education (mean years of schooling completed and expected years of schooling upon entering the education system), and per capita income indicators, which is used to rank countries into four tiers of human development. A country scores a higher level of HDI when the lifespan is higher, the education level is higher, and the gross national income GNI (PPP) per capita is higher. It was developed by Pakistani economist Mahbub ul-Haq and was further used to measure a country's development by the United Nations Development Programme (UNDP)'s Human Development Report Office.
The 2010 Human Development Report introduced an inequality-adjusted Human Development Index (IHDI). While the simple HDI remains useful, it stated that "the IHDI is the actual level of human development (accounting for this inequality), while the HDI can be viewed as an index of 'potential' human development (or the maximum level of HDI) that could be achieved if there was no inequality."
The index is based on the human development approach, developed by Mahbub ul-Haq, anchored in Amartya Sen's work on human capabilities, and often framed in terms of whether people are able to "be" and "do" desirable things in life. Examples include — being: well-fed, sheltered, and healthy; doing: work, education, voting, participating in community life. The freedom of choice is considered central — someone choosing to be hungry (e.g. when fasting for religious reasons) is considered different from someone who is hungry because they cannot afford to buy food, or because the country is going through a famine.
The index does not take into account several factors, such as the net wealth per capita or the relative quality of goods in a country. This situation tends to lower the ranking of some of the most developed countries, such as the G7 members and others.
Origins
The origins of the HDI are found in the annual Human Development Reports produced by the Human Development Report Office of the United Nations Development Programme (UNDP). These annual reports were devised and launched by Pakistani economist Mahbub ul-Haq in 1990, and had the explicit purpose "to shift the focus of development economics from national income accounting to people-centered policies". He believed that a simple composite measure of human development was needed to convince the public, academics and politicians that they can, and should, evaluate development not only by economic advances but also improvements in human well-being.
Dimensions and calculation
New method (2010 HDI onwards)
Published on 4 November 2010 (and updated on 10 June 2011), the 2010 Human Development Report calculated the HDI combining three dimensions:
A long and healthy life: Life expectancy at birth
Education: Mean years of schooling and expected years of schooling
A decent standard of living: GNI per capita (PPP international dollars)
In its 2010 Human Development Report, the UNDP began using a new method of calculating the HDI. The following three indices are used:
1. Life Expectancy Index (LEI)
LEI is equal to 1 when life expectancy at birth is 85 years, and 0 when life expectancy at birth is 20 years.
2. Education Index (EI)
2.1 Mean Years of Schooling Index (MYSI)
Fifteen is the projected maximum of this indicator for 2025.
2.2 Expected Years of Schooling Index (EYSI)
Eighteen is equivalent to achieving a master's degree in most countries.
3. Income Index (II)
II is 1 when GNI per capita is $75,000 and 0 when GNI per capita is $100.
Finally, the HDI is the geometric mean of the previous three normalized indices:
LE: Life expectancy at birth
MYS: Mean years of schooling (i.e. years that a person aged 25 or older has spent in formal education)
EYS: Expected years of schooling (i.e. total expected years of schooling for children under 18 years of age, incl. young men and women aged 13–17)
GNIpc: Gross national income at purchasing power parity per capita
Old method (HDI before 2010)
The HDI combined three dimensions last used in its 2009 report:
Life expectancy at birth, as an index of population health and longevity to HDI
Knowledge and education, as measured by the adult literacy rate (with two-thirds weighting) and the combined primary, secondary, and tertiary gross enrollment ratio (with one-third weighting).
Standard of living, as indicated by the natural logarithm of gross domestic product per capita at purchasing power parity.
This methodology was used by the UNDP until their 2011 report.
The formula defining the HDI is promulgated by the United Nations Development Programme (UNDP). In general, to transform a raw variable, say , into a unit-free index between 0 and 1 (which allows different indices to be added together), the following formula is used:
where and are the lowest and highest values the variable can attain, respectively.
The Human Development Index (HDI) then represents the uniformly weighted sum with contributed by each of the following factor indices:
Life Expectancy Index
Education Index
Adult Literacy Index (ALI)
Gross Enrollment Index (GEI)
GDP
2022 Human Development Index (2024 report)
The Human Development Report 2023/24 by the United Nations Development Programme was released on 13 March 2024; the report calculates HDI values based on data collected in 2022.
Ranked from 1 to 69 in the year 2022, the following countries are considered to be of "very high human development":
Past top countries
The list below displays the top-ranked country from each year of the Human Development Index. Norway has been ranked the highest sixteen times, Canada eight times, and Switzerland, Japan, and Iceland have each ranked twice.
In each original HDI
The year represents the time period from which the statistics for the index were derived. In parentheses is the year when the report was published.
Geographical coverage
The HDI has extended its geographical coverage: David Hastings, of the United Nations Economic and Social Commission for Asia and the Pacific, published a report geographically extending the HDI to 230+ economies, whereas the UNDP HDI for 2009 enumerates 182 economies and coverage for the 2010 HDI dropped to 169 countries.
Country/region specific HDI lists
Afghan regions
Angolan provinces
African countries
Albanian counties
Algerian regions
Argentine provinces
Armenian provinces
Australian states
Austrian states
Azerbaijani regions
Baltic regions
Bangladeshi districts and divisions
Belgian provinces
Bolivian departments
Bosnia and Herzegovina regions
Brazilian states
Canadian provinces and territories
Chilean regions
Chinese administrative divisions
Colombian departments
Croatian counties
Danish regions
Dutch provinces
Egyptian governorates
Ethiopian regions
European countries
Finnish regions
French regions
German states
Georgian regions
Greek regions
Indian states
Tamil Nadu districts (India)
Indonesian provinces
Iranian provinces
Iraqi governorates
Italian regions
Kazakhstan regions
Japanese prefectures
Jordanian governorates
Latin American countries
Malaysian states
Mexican states
Myanmar administrative divisions
Nepalese provinces
New Zealand regions
Nigerian states
Norwegian regions
Pakistani administrative units
Philippine provinces
Palestinian regions
Polish voivodeships
Romanian regions
Russian federal subjects
Serbian Regions
South African provinces
South Korean regions
Spanish communities
Swedish regions
Syrian governorates
Swiss regions
Thai regions
Turkish regions
UK regions
Ukrainian regions
U.S. states (American Human Development Report (AHDR))
Venezuelan states
Vietnamese regions
Criticism
The Human Development Index has been criticized on a number of grounds, including focusing exclusively on national performance and ranking, lack of attention to development from a global perspective, measurement error of the underlying statistics, and on the UNDP's changes in formula which can lead to severe misclassification of "low", "medium", "high" or "very high" human development countries.
There have also been various criticism towards the lack of consideration regarding sustainability (which later got addressed by the planetary pressures-adjusted HDI), social inequality (which got addressed by the inequality-adjusted HDI), unemployment or democracy.
Sources of data error
Economists Hendrik Wolff, Howard Chong and Maximilian Auffhammer discuss the HDI from the perspective of data error in the underlying health, education and income statistics used to construct the HDI. They have identified three sources of data error which are: (i) data updating, (ii) formula revisions and (iii) thresholds to classify a country's development status. They conclude that 11%, 21% and 34% of all countries can be interpreted as currently misclassified in the development bins due to the three sources of data error, respectively. Wolff, Chong and Auffhammer suggest that the United Nations should discontinue the practice of classifying countries into development bins because the cut-off values seem arbitrary, and the classifications can provide incentives for strategic behavior in reporting official statistics, as well as having the potential to misguide politicians, investors, charity donors and the public who use the HDI at large.
In 2010, the UNDP reacted to the criticism by updating the thresholds to classify nations as low, medium, and high human development countries. In a comment to The Economist in early January 2011, the Human Development Report Office responded to an article published in the magazine on 6 January 2011 which discusses the Wolff et al. paper. The Human Development Report Office states that they undertook a systematic revision of the methods used for the calculation of the HDI, and that the new methodology directly addresses the critique by Wolff et al. in that it generates a system for continuously updating the human-development categories whenever formula or data revisions take place.
In 2013, Salvatore Monni and Alessandro Spaventa emphasized that in the debate of GDP versus HDI, it is often forgotten that these are both external indicators that prioritize different benchmarks upon which the quantification of societal welfare can be predicated. The larger question is whether it is possible to shift the focus of policy from a battle between competing paradigms to a mechanism for eliciting information on well-being directly from the population.
See also
Corruption Perceptions Index
Gender Inequality Index
OECD Better Life Index (BLI)
World Happiness Report
International development
List of sovereign states by percentage of population living in poverty
Right to an adequate standard of living
Sustainable Development Goals (SDGs)
References
External links
Human Development Index
Human Development Tools and Rankings
Development economics
Environmental economics
International rankings
Science and technology in Pakistan
Pakistani inventions
1990 establishments
sah:HDI | Human Development Index | Environmental_science | 2,109 |
27,278,390 | https://en.wikipedia.org/wiki/Alternate%20lighting%20of%20surfaces | Alternate lighting of surfaces (ALiS) is type of plasma display technology jointly developed by Fujitsu and Hitachi in 1999. Alternate lighting of surfaces uses an interlaced scanning method rather than a progressive one. This technique allows native lower resolution plasma display panels to display at higher resolutions. This technique also helps in prolonging panel life and power consumption reductions.
References
Display technology | Alternate lighting of surfaces | Engineering | 77 |
19,420,562 | https://en.wikipedia.org/wiki/NGC%205821 | NGC 5821 is a spiral galaxy with a ring structure in the constellation Boötes. It lies near a similarly massed galaxy, NGC 5820, at the same redshift. Both galaxies were discovered by the astronomer William Herschel.
References
External links
Distance
Image NGC 5821
SIMBAD data
NGC 5821
5821
09648
53532
53532
+09-25-002
Spiral galaxies | NGC 5821 | Astronomy | 84 |
5,296,451 | https://en.wikipedia.org/wiki/Platinum%28IV%29%20chloride | Platinum(IV) chloride is the inorganic compound of platinum and chlorine with the empirical formula PtCl4. This brown solid features platinum in the 4+ oxidation state.
Structure
Typical of Pt(IV), the metal centers adopt an octahedral coordination geometry, {PtCl6}. This geometry is achieved by forming a polymer wherein half of the chloride ligands bridge between the platinum centers. Because of its polymeric structure, PtCl4 dissolves only upon breaking the chloride bridging ligands. Thus, addition of HCl give H2PtCl6. Lewis base adducts of Pt(IV) of the type cis-PtCl4L2 are known, but most are prepared by oxidation of the Pt(II) derivatives.
Formation and reactions
PtCl4 is mainly encountered in the handling of chloroplatinic acid, obtained by dissolving of Pt metal in aqua regia. Heating H2PtCl6 to 220 °C gives impure PtCl4:
H2PtCl6 → PtCl4 + 2 HCl
A purer product can be produced by heating under chlorine gas at 250 °C.
If excess acids are removed, PtCl4 crystallizes from aqueous solutions in large red crystals of pentahydrate PtCl4·5(H2O), which can be dehydrated by heating to about 300 °C in a current of dry chlorine. The pentahydrate is stable and is used as the commercial form of PtCl4.
Treatment of PtCl4 with aqueous base gives the [Pt(OH)6]2− ion. With methyl Grignard reagents followed by partial hydrolysis, PtCl4 converts to the cuboidal cluster [Pt(CH3)3(OH)]4. Upon heating PtCl4 evolves chlorine to give PtCl2:
PtCl4 → PtCl2 + Cl2
The heavier halides, PtBr4 and PtI4, are also known.
References
Cotton, S. A. Chemistry of Precious Metals, Chapman and Hall (London): 1997. .
Chlorides
Chlorides,4
Platinum group halides | Platinum(IV) chloride | Chemistry | 453 |
78,088,838 | https://en.wikipedia.org/wiki/Alarmo | The Nintendo Sound Clock: Alarmo is a digital alarm clock developed and produced by Nintendo. It was released exclusively at Nintendo stores and online for Nintendo Switch Online subscribers on October 10, 2024. A wide release of the device is set for March 2025.
Features
The device consists of a 2.8" LCD screen to display the time and other metrics, as well as a large light-up dial which can be used to navigate menus. As a ‘smart’ alarm clock it has a 2.4 GHz WiFi connectivity for firmware and content download. Unlike traditional alarm clocks, Alarmo uses a 24 GHz mmWave presence sensor to detect motion during sleep and waking up. The longer the user stays in bed without moving, the louder and more intense the sound of the alarm will become. Alarmo will play game sounds as the user starts to move around in bed, and will play a fanfare once they are out of bed completely. Additionally, the user can also view sleep records from the device and play ambient music at night while falling asleep.
Alarmo can be set to various game themes based on various Nintendo Switch titles, which will alter the display of the clock as well as the music and sounds that play. At launch, the clock contained themes for Super Mario Odyssey, The Legend of Zelda: Breath of the Wild, Splatoon 3, Pikmin 4, and Ring Fit Adventure. Each game theme contains seven alarms, for a total of 35 alarms pre-installed with the device. Further themes are planned to be added over time and can be installed wirelessly with a connected Nintendo account. A theme for Mario Kart 8 Deluxe was released in an update on December 10, 2024, and a theme for Animal Crossing: New Horizons is confirmed to be releasing in the future. Additionally, the clock displays a render of a character from a chosen theme beneath the current time which moves to the left or right of the display depending on detected movements.
Development
Nintendo first announced their intentions to create a sleep-tracking device during a financial briefing in 2014, which was intended to mark their entry into the "quality of life" market. The device, which would have used sensors to track a user's sleeping habits similarly to Alarmo, was being developed in partnership with health company ResMed but had been put on hold indefinitely in 2016.
Alarmo was developed in house by Nintendo's motion sensor research team. As the device's sensors could detect motion without the use of a camera, it was thought that the technology would be appropriate for use in a bedroom. Earlier prototypes of Alarmo lacked any design elements or sounds from other Nintendo properties. One such prototype used an LED dot-matrix display instead of a screen, however, the development team believed that it would be harder to use.
Release
The Alarmo was announced by Nintendo on October 9, 2024, and on the same day, it was released exclusively at Nintendo's official stores. It also became available to purchase online for Nintendo Switch Online subscribers. A wide release of the device is set for 2025. In Australia and New Zealand, a wide release is set for March 2025, and Nintendo Switch Online members can register for a chance to be able to pre-purchase the device early on November 13, 2024.
On October 10, 2024, Nintendo announced that, due to a large number of orders in Japan, they would no longer take new online orders in that region, and that the purchase method would be switching to a lottery-based system. The same day, the Alarmo was sold out at the Nintendo stores in New York City, Tokyo, Osaka, and Kyoto. One day later, Nintendo announced that the ability for Nintendo Switch Online members in Japan to register for a chance to purchase the device online, using the aforementioned lottery system, had begun.
2.0.0 Update
Nintendo released a major update for the Alarmo on October 9, 2024, the same date the device launched, bringing the version number to 2.0.0. It added new features, including Moderate Mode, and Movement records.
Reception
Early reactions to Alarmo found the alarm clock to be a surprising and unusual product for Nintendo to reveal, especially surrounding speculation about the announcement of the then-unannounced Nintendo Switch 2. Critics noted the expensive price point of Alarmo when compared to a traditional clock, as well as some limitations of the device including a lack of support for some bed sizes and multiple people or pets in one bed.
Nintendo Life awarded the device a 7/10, describing it as "a fun little device that's easy to use and will absolutely appeal to Nintendo fans both young and old if you value fun and whimsy over accuracy." They found the lack of an included AC adapter to be an inconvenience, noting that an adapter felt necessary for an alarm clock. They described the setup process as "very easy and very Nintendo, meaning there's a sliver of fun to be had in what is otherwise a straightforward affair". However, they recommended that if the Alarmo was being purchased for a young child, an adult should likely set up the device beforehand, stating that "there's nothing particularly difficult here, but you do need to understand what type of bed is in use (single, double, king, etc) along with where the Alarmo will be placed in relation to the bed itself". They praised the sound quality, saying, "[...] the volume isn't going to compete with the likes of an Alexa or a Bose speaker, but it does the job considering how close you're likely to be when sleeping. You can easily turn the volume up or down with the dial from the main screen, and the quality remains crisp and clear even at maximum." The Verge praised the design of the clock but criticized the motion-tracking technology's limited functionality and the sleep sounds only lasting 10 minutes, saying, "It’s first and foremost a $100 Nintendo-branded clock. It looks and sounds the part, which is to say, it’s incredibly charming and nostalgic. But if you’re looking for something to help you wake up better than a run-of-the-mill alarm or track your sleep more efficiently than an app on your phone, this isn’t it. Turns out, even adorable pikmin and inklings can’t change my mind about alarm clocks."
CNET’s Scott Stein gave it a mostly positive review, calling it “a novelty clock, a fun musical gift for the room of a kid or a Nintendo superfan”. “It’s absolutely charming and fine, but it’s not a drop-dead amazing thing either.” Scott added.
References
Nintendo hardware
Alarms
Products introduced in 2024
Clocks | Alarmo | Physics,Technology,Engineering | 1,385 |
45,405,694 | https://en.wikipedia.org/wiki/Eschmeyer%27s%20Catalog%20of%20Fishes | Catalog of Fishes is a comprehensive on-line database and reference work on the scientific names of fish species and genera. It is global in its scope and is hosted by the California Academy of Sciences. It has been compiled and is continuously updated by the curator emeritus of the CAS fish collection, William N. Eschmeyer.
The taxonomy maintained by the Catalog of Fishes is considered authoritative and it is used as a baseline reference for instance by the broader global fish database FishBase, which involves cross-references to the Catalog's information for all accepted taxa. the searchable catalogue contains entries for about 58,300 fish species names, about 33,400 of which are currently accepted (valid), and for some 10,600 genera (5,100 valid). The information given for any species name generally contains the reference to the original description, to the type specimen, references to the usage of the name in taxonomic literature, a statement of the current status of the name and valid name of the taxon, and the family it belongs to.
A printed 3000-page three-volume and CD version of the Catalogue was published in 1998. That was preceded by a Catalog of the genera of recent fishes in 1990.
The Catalog was renamed Eschmeyer's Catalog of Fishes in 2019, and is now edited by Ronald Fricke, Richard van der Laan and William N. Eschmeyer. It is available online, and updated monthly.
See also
FishBase
WoRMS
Fishes of the World
International Code of Zoological Nomenclature
References
Original resource
Eschmeyer, W.N. Catalog of Fishes Online Database
Eschmeyer, W.N. (ed.) 1998. Catalog of fishes. Special Publication, California Academy of Sciences, San Francisco. 3 vols. 2905 p.
Eschmeyer, W.N. 1990. Catalog of the genera of recent fishes. California Academy of Sciences, San Francisco. 697 p.
Biodiversity databases
Fish taxonomy
Ichthyological literature | Eschmeyer's Catalog of Fishes | Biology,Environmental_science | 394 |
18,326,471 | https://en.wikipedia.org/wiki/Cool%20Earth%2050 | Cool Earth 50 (also known as Cool Earth) is a plan developed by Japan to reduce global CO2 emissions 50% by 2050, which was discussed at the 34th G8 summit. Cool Earth 50 is planned to be a framework that would continue towards the goals set forth in the Kyoto Protocols. This plan includes three proposals: a long-term strategy, a mid-term strategy and launching a national campaign for achieving the Kyoto Protocol Target.
The plan was first proposed on May 24, 2007, at an international conference called Asian Future and was initiated by Japanese Prime Minister Shinzo Abe. The program's goal is to reduce current global green house emissions by 50% by the year 2050. The goal of reduction was aimed particular towards the largest green house emitting countries The United States, China, Japan, and India. Also, for the major green house emitters to create a frame work for reduction. Cool Earth aims at reducing green house emissions by improving technology in energy fields. A large goal of Cool Earth is to promote economic prosperity through green technology and to encourage political stability domestically and internationally.
Proposals
The proposals of this program include:
A long-term strategy for global reduction of greenhouse gas emissions.
Propose three principles for establishing an international framework for addressing global warming from 2013 onward.
To launch a national campaign to ensure Japan achieves the Kyoto Protocol goal.
In addition, the proposal sets to make technological advancements in:
Zero-emissions coal-fired power generation
Reactors for nuclear power generation
Technology for high-efficiency and low-cost solar power generation
Technology for the use of hydrogen
Ultra high energy efficiency technology
Course 50
Course 50 is a reduction strategy to reduce emissions by 30%. The aim of Course 50 is to suppress emissions from blast furnaces and to capture from blast furnaces. The goal is to reach reduction by the year 2030. The programs first phase was initiated in the year 2008 and funded by New Energy and Industrial Technology Development Organization.The original budget was approximately 10 billion yen. Course 50 is encouraging innovation in technology towards more effective capturing polymers, as well as temperature reduction and improved efficiency of blast furnaces in the steel industrious.
Solar
Japan with Cool Earth has been expanding their solar power industry offering subsidies to improving solar powered infrastructure. The main research goal is to achieve a low cost high efficiency solar cell that offers a conversion efficiency of 40%.
Hydrogen power
In 2009, Japan fitted over 100,000 homes with hydrogen powered fuel cells, improving its hydrogen powered infrastructure.
Energy efficient technology
New development of LED light bulbs that utilize blue and white light has improved efficiency by over 25% since 2008. The use of SerDes router technology having the capability to reduce energy waste from routers by over 50%.
See also
Climate change in Japan
Emissions reduction efforts
References
External links
Cool Earth 50 at the Japanese Ministry of Foreign Affairs
"Cool Earth 50" welcome (in Nihongo), 2007
Environment of Japan
G7 summits
Climate change in Japan
Emissions reduction
2007 introductions
2007 establishments in Japan | Cool Earth 50 | Chemistry | 604 |
60,337,599 | https://en.wikipedia.org/wiki/Retractile%20drawbridge | A retractile drawbridge is a rare type of moveable bridge in which the span is pulled away diagonally on rails. It is a variant of the retractable bridge. Only four examples are known to exist in the United States. It is believed to have been invented by T. Willis Pratt in the 1860s.
References
Bridges | Retractile drawbridge | Engineering | 70 |
30,852,579 | https://en.wikipedia.org/wiki/Glass%20House%20%28British%20Columbia%29 | The Glass House, built by David H. Brown, is located on the east shore of Kootenay Lake in British Columbia near the rural locality of Boswell, British Columbia. Construction started in 1952 in order to, according to a quote left by Mr. Brown, "indulge a whim of a peculiar nature". Intended to be the Browns' home, the unusual construction and fantasy-castle appearance attracted traffic from the adjacent British Columbia Highway 3A (now part of the scenic International Selkirk Loop). The resulting loss of privacy led to the Browns' establishment of a roadside attraction in the summer months.
The Glass House sits upon solid rock overlooking Kootenay Lake and is constructed of approximately 500,000 empty embalming fluid bottles, which would have otherwise been discarded as waste. Built with a single layer of bottles laid with the short neck towards the inside, strips of wood were wired between the necks and reinforced with cement. The strips of wood then support the inner walls formed of cedar boards.
The main house is built like a three-leaf clover with the main rooms being circular. A short staircase in the center accounts for the different heights created by the rock on which the house sits. The main floor contains the living room with a large fireplace, the master bedroom, and a kitchen overlooking a terrace. A second bedroom resides upstairs, off-limits to visitors, and brings the total square footage to 1200 (approximately 111 square metres). Additional structures include a wishing well with waterwheel, an archway, a garden shed, a bridge, several towers, and many stone stairs and pathways. These additional buildings are also primarily constructed with the same technique as the house.
References
Roadside attractions in Canada
Novelty buildings in Canada
West Kootenay
Bottle houses | Glass House (British Columbia) | Engineering | 354 |
9,548,777 | https://en.wikipedia.org/wiki/Vulcan%20Street%20Plant | The Vulcan Street Plant was the first Edison hydroelectric central station. The plant was built on the Fox River in Appleton, Wisconsin, and put into operation on September 30, 1882. According to the American Society of Mechanical Engineers, the Vulcan Street plant is considered to be "the first hydro-electric central station to serve a system of private and commercial customers in North America". It is a National Historic Mechanical Engineering Landmark, an IEEE milestone and a National Historic Civil Engineering Landmark.
The Vulcan Street Plant was housed in the Appleton Paper and Pulp Company building, which burned to the ground in 1891. A replica of the Vulcan Street Plant was later built on South Oneida Street.
Origin
The Vulcan Street Plant was conceptualized by H. J. Rogers – who was the president of the Appleton Paper and Pulp Co. and of the Appleton Gas Light Co. during this time. According to the Institute of Electrical and Electronics Engineering, H. J. Rogers first came up with the idea for a hydro-electric central station after talking with a friend of his, H. E. Jacobs, while they were on a fishing trip.
The Appleton Edison Electric Light Company
H. E. Jacobs, who was working for Western Edison Light Company of Chicago as a licensing agent, informed H. J. Rogers about Thomas Edison’s plan for a steam-driven electric power plant in New York City called the Pearl Street Plant. Upon learning about Edison’s advances in electric light technology and electric generators, Rogers worked to bring together a group of investors to create one of the first hydro-electric central stations in the world. For this reason, the Appleton Edison Electric Light Company was formed and incorporated on May 25, 1882.
While Edison’s Pearl Street Plant was still under construction, the founders of the Appleton Edison Electric Light Company – H. E. Jacobs, A. L. Smith, H. D. Smith, and Charles Beveridge – began planning the Vulcan Street Plant.
In July 1882, engineer P. D. Johnston, who worked for Western Edison Light Company of Chicago during this time, visited Appleton to explain the details of Edison’s lighting system to the founders of the Appleton Edison Electric Light Company. After this meeting, the founders decided to test the viability of hydro-electric lighting by first installing it in their homes and mills.
As a result, two Edison "K" type generators were ordered. The first generator was installed in H. J. Roger’s paper mill, the Appleton Paper and Pulp Company, and is the generator that began operation on September 30, 1882. The second generator was installed in its building on Vulcan Street and began operation on November 25, 1882.
Problems and successes
On September 27, 1882, the first generator began operation, but without success. Hence, Edward T. Ames, the installer, returned to Appleton to correct the problem.
After a few days of troubleshooting, the generator was repaired and successfully entered operation on September 30, 1882. This was only 26 days after Thomas Edison began to successfully operate his steam-driven Pearl Street Plant in New York, which began operation on September 4, 1882. The output of the original generator was about 12.5 kilowatts.
The first buildings to be lit by the Vulcan Street Plant were H.J. Rogers' home, the Appleton Paper and Pulp Company building, and the Vulcan Paper Mill, which were all connected directly to the generator.
Initially, the buildings' direct connection to the generator caused many problems because the generator was directly connected to the waterwheel. The water from the Fox River did not flow at a constant rate, so the lights did not maintain constant brightness and often burned out.
This problem was resolved by moving the generator to a lean-to off the main building, where it was attached to a separate water wheel that allowed for a more even load distribution.
During the time of the Vulcan Street Plant, voltage regulators did not exist. Operators had to look at the light itself to determine if it was at the proper brightness, and they adjusted the voltage according to their observations. Electricity meters did not exist at that time, so customers were charged a flat monthly fee based on the number of electric lamps installed in their building. Hence, many people left their lights on all night.
The original electric distribution lines in Appleton were made of bare copper. This posed many challenges in the early development of commercial electricity, because nearly everything was made of wood or other flammable materials. The wiring used in buildings was insulated by a thin layer of cotton and was fastened to walls using wood cleats. Likewise, wood was used for fuse boxes, light sockets, and switch handles.
Appleton's first electrically lit buildings
H. J. Rogers' home, which has been converted to be the Hearthstone Historic House Museum, is one of the few surviving examples of wiring and lighting fixtures from the dawn of the electrical age. The Vulcan Street Plant and the Appleton Paper and Pulp Company building burned to the ground in 1891, and the Vulcan Paper Mill was dismantled in 1908.
After the Vulcan Street Plant was destroyed by fire, an exact replica was built on South Oneida Street and was opened to the public on September 30, 1932. According to the minutes taken at the Appleton Historic Preservation Committee meeting on October 21, 2008, the replica of the Vulcan Street Plant was, "... painstakingly constructed duplicating all of the building's original features."
This site was dedicated as an ASME National Historic Engineering Landmark, jointly designated with ASCE and IEEE on September 15, 1977.
See also
War of the currents
Samuel Insull
References
Energy infrastructure completed in 1882
Buildings and structures in Appleton, Wisconsin
Hydroelectric power plants in Wisconsin
Historic Civil Engineering Landmarks | Vulcan Street Plant | Engineering | 1,154 |
68,861,695 | https://en.wikipedia.org/wiki/Association%20of%20Polish%20Electrical%20Engineers | The Association of Polish Electrical Engineers (Stowarzyszenie Elektryków Polskich, SEP; also called Association of Polish Electricians) is a Polish non-governmental organisation integrating the community of electricians of Polish origin worldwide. The organisation brings together both engineers and technicians, as well as young students (pupils of technical and vocational schools) in electrical engineering in the broadest sense.
Activities
SEP is mainly involved in education activities (training courses for the operation of electrical equipment). It is also involved in conformity assessment of low-voltage electrical products (since 1933), through its office of quality, an SEP agency with national accreditations and recognition from the most prestigious international and European organisations. It also carries out extensive international cooperation under the English name of "Association of Polish Electrical Engineers". It is a member of the National Federation of Scientific and Technical Associations of Poland and the European organisation EUREL.
History
From 7 to 9 June 1919, a congress was held to establish the Association of Polish Electrical Engineers. Professor Mieczysław Pożaryski was elected its first president. In 1928 the organisation merged with the Association of Polish Radio Engineers, and in 1929 the name was changed to its present name by a decision of the board of directors. In 1939, the Association of Polish Telecommunication Engineers joined SEP.
Presidents
1919–1928 – Mieczysław Pożaryski (first president of the SEP)
1928–1929 – Kazimierz Straszewski
1929–1930 – Zygmunt Okoniewski
1930–1931 – Kazimierz Straszewski
1931–1932 – Felicjan Karśnicki
1932–1933 – Tadeusz Czaplicki
1933–1934 – Alfons Kühn
1934–1935 – Jan Obrąpalski
1935–1936 – Alfons Kühn
1936–1937 – Janusz Groszkowski
1937–1938 – Alfons Hoffmann
1938–1939 – Kazimierz Szpotański
1939 – Antoni Krzyczkowski
1939–1946 – Kazimierz Szpotański
1946–1947 – Kazimierz Straszewski
1947–1949 – Włodzimierz Szumilin
1949–1950 – Stanisław Ignatowicz
1950–1951 – Tadeusz Żarnecki
1951–1952 – Jerzy Lando
1952–1959 – Kazimierz Kolbiński
1959–1961 – Tadeusz Kahl
1961–1981 – Tadeusz Dryzek
1981–1987 – Jacek Szpotański
1987–1990 – Bohdan Paszkowski
1990–1994 – Jacek Szpotański
1994–1998 – Cyprian Brudkowski
1998–2002 – Stanisław Bolkowski
2002–2006 – Stanisław Bolkowski
2006–2014 – Jerzy Barglik
2014–2022 – Piotr Szymczak
from 2022 – Sławomir Cieślik
References
External links
Official Website
Professional associations based in Poland
Certification marks
Standards organisations in Poland
Product-testing organizations
1919 establishments in Poland
Organizations established in 1919
Organisations based in Warsaw | Association of Polish Electrical Engineers | Mathematics | 625 |
38,706,738 | https://en.wikipedia.org/wiki/Maliit | Maliit is an input method framework for computers with particular focus on implementing virtual keyboards. Designed mostly for touchscreen devices, Maliit allows the inputting of text without the presence of a physical keyboard. More advanced features such as word correction and prediction are also available.
Originating as part of MeeGo, Maliit is free software licensed under LGPL. Maliit ships as a standard component of LG webOS, Plasma Mobile, SailfishOS, LuneOS, and Ubuntu Touch.
History
Maliit was originally developed as part of MeeGo by Nokia who eventually shipped it as part of MeeGo Handset “Day 1” software platform.
In the early 2010s, Maliit was deployed as a standard component of Nokia N9, KDE Plasma Active, OLPC devices, and Ubuntu Touch phones.
After the MeeGo project ended, Maliit was transferred into an independent project by free software consulting firm Openismus. The first formally independent release was 0.80.0 on .
Maliit 0.99, released on , switched from Qt 4 to Qt 5.
In May 2016, a KDE developer announced that instead of Maliit, QtVirtualKeyboard had been integrated into KDE Plasma 5.7. In September 2020, Maliit was made the default keyboard in Plasma Mobile.
On Maliit 2.0 has been released.
Features
Among Maliit's features are a plugin-based architecture, word correction and prediction, multitouch, and context sensitive layouts.
When running on Linux kernel, handling of the input hardware relies on evdev. Maliit supports X11 as well as Wayland.
See also
List of input methods for UNIX platforms
External links
References
Input methods
Nokia services
Mobile Linux
Free mobile software
Free software programmed in C++ | Maliit | Technology | 369 |
1,605,743 | https://en.wikipedia.org/wiki/Fundamental%20pair%20of%20periods | In mathematics, a fundamental pair of periods is an ordered pair of complex numbers that defines a lattice in the complex plane. This type of lattice is the underlying object with which elliptic functions and modular forms are defined.
Definition
A fundamental pair of periods is a pair of complex numbers such that their ratio is not real. If considered as vectors in , the two are linearly independent. The lattice generated by and is
This lattice is also sometimes denoted as to make clear that it depends on and It is also sometimes denoted by or or simply by The two generators and are called the lattice basis. The parallelogram with vertices is called the fundamental parallelogram.
While a fundamental pair generates a lattice, a lattice does not have any unique fundamental pair; in fact, an infinite number of fundamental pairs correspond to the same lattice.
Algebraic properties
A number of properties, listed below, can be seen.
Equivalence
Two pairs of complex numbers and are called equivalent if they generate the same lattice: that is, if
No interior points
The fundamental parallelogram contains no further lattice points in its interior or boundary. Conversely, any pair of lattice points with this property constitute a fundamental pair, and furthermore, they generate the same lattice.
Modular symmetry
Two pairs and are equivalent if and only if there exists a matrix with integer entries and and determinant such that
that is, so that
This matrix belongs to the modular group This equivalence of lattices can be thought of as underlying many of the properties of elliptic functions (especially the Weierstrass elliptic function) and modular forms.
Topological properties
The abelian group maps the complex plane into the fundamental parallelogram. That is, every point can be written as for integers with a point in the fundamental parallelogram.
Since this mapping identifies opposite sides of the parallelogram as being the same, the fundamental parallelogram has the topology of a torus. Equivalently, one says that the quotient manifold is a torus.
Fundamental region
Define to be the half-period ratio. Then the lattice basis can always be chosen so that lies in a special region, called the fundamental domain. Alternately, there always exists an element of the projective special linear group that maps a lattice basis to another basis so that lies in the fundamental domain.
The fundamental domain is given by the set which is composed of a set plus a part of the boundary of
where is the upper half-plane.
The fundamental domain is then built by adding the boundary on the left plus half the arc on the bottom:
Three cases pertain:
If and , then there are exactly two lattice bases with the same in the fundamental region: and
If , then four lattice bases have the same the above two , and ,
If , then there are six lattice bases with the same , , and their negatives.
In the closure of the fundamental domain: and
See also
A number of alternative notations for the lattice and for the fundamental pair exist, and are often used in its place. See, for example, the articles on the nome, elliptic modulus, quarter period and half-period ratio.
Elliptic curve
Modular form
Eisenstein series
References
Tom M. Apostol, Modular functions and Dirichlet Series in Number Theory (1990), Springer-Verlag, New York. (See chapters 1 and 2.)
Jurgen Jost, Compact Riemann Surfaces (2002), Springer-Verlag, New York. (See chapter 2.)
Riemann surfaces
Modular forms
Elliptic functions
Lattice points | Fundamental pair of periods | Mathematics | 701 |
37,962,086 | https://en.wikipedia.org/wiki/94%20Piscium | 94 Piscium is a single star in the zodiac constellation Pisces, located 305 light years away from the Sun. It is visible to the naked eye as a faint, orange-hued star with an apparent visual magnitude of 5.495. The object is moving closer to the Earth with a heliocentric radial velocity of −43 km/s. It is a possible member of the Wolf 630 moving group.
This is an evolved K-type giant star with a stellar classification of K1 III. It is a red clump giant, which indicates it is on the horizontal branch and is generating energy through helium fusion at its core. The star is 4.1 billion years old with 1.34 times the mass of the Sun and 13 times the Sun's radius. It is radiating 69 times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,665 K.
References
K-type giants
Horizontal-branch stars
Pisces (constellation)
Durchmusterung objects
Piscium, 094
008763
006732
0414 | 94 Piscium | Astronomy | 227 |
26,769,724 | https://en.wikipedia.org/wiki/866A | The 866 is a mercury vapor half-wave rectifier intended for high-voltage applications. The voltage drop is approximately 15 volts up to 150 Hz. To avoid unwanted shorts the tube must be operated in a vertical position and the filament preheated for at least 30 seconds before applying the plate voltage.
Construction
Structurally, it consists of a linear electrode arrangement; a cup shaped anode with top cap and a cylindrical cathode. The socket is a medium 4 pin bayonet UX-4 and the glass envelope is ST-19. The 2.5 volt/ 5 Amp filament is connected to pins 1 and 4.
Operation
Under normal operating conditions the tube glows blue and mercury droplets are visible.
Pictures in working conditions
References
Further reading
External links
866 @ The National Valve Museum
866A at Radiomuseum.org
Vacuum tubes
Electric power conversion | 866A | Physics | 183 |
1,893,537 | https://en.wikipedia.org/wiki/Yaw%20drive | The yaw drive is an important component of the horizontal axis wind turbines' yaw system. To ensure the wind turbine is producing the maximal amount of electric energy at all times, the yaw drive is used to keep the rotor facing into the wind as the wind direction changes. This only applies for wind turbines with a horizontal axis rotor. The wind turbine is said to have a yaw error if the rotor is not aligned to the wind. A yaw error implies that a lower share of the energy in the wind will be running through the rotor area. (The generated energy will be approximately proportional to the cosine of the yaw error).
History
When the windmills of the 18th century included the feature of rotor orientation via the rotation of the nacelle, an actuation mechanism able to provide that turning moment was necessary. Initially the windmills used ropes or chains extending from the nacelle to the ground in order to allow the rotation of the nacelle by means of human or animal power.
Another historical innovation was the fantail. This device was actually an auxiliary rotor equipped with plurality of blades and located downwind of the main rotor, behind the nacelle in a 90° (approximately) orientation to the main rotor sweep plane. In the event of change in wind direction the fantail would rotate thus transmitting its mechanical power through a gearbox (and via a gear-rim-to-pinion mesh) to the tower of the windmill. The effect of the aforementioned transmission was the rotation of the nacelle towards the direction of the wind, where the fantail would not face the wind thus stop turning (i.e. the nacelle would stop to its new position).
The modern yaw drives, even though electronically controlled and equipped with large electric motors and planetary gearboxes have great similarities to the old windmill concept.
Types
The main categories of yaw drives are:
The Electric Yaw Drives: Commonly used in almost all modern turbines.
The Hydraulic Yaw Drive: Hardly ever used anymore on modern wind turbines.
Components
Gearbox
The gearbox of the yaw drive is a very crucial component since it is required to handle very large moments while requiring the minimal amount of maintenance and perform reliably for the whole life-span of the wind turbine (approx. 20 years). Most of the yaw drive gearboxes have input to output ratios in the range of 2000:1 in order to produce the enormous turning moments required for the rotation of the wind turbine nacelle.
Gear rim and pinions
The gear-rim and the pinions of the yaw drives are the components that finally transmit the turning moment from the yaw drives to the tower in order to turn the nacelle of the wind turbine around the tower axis (z axis). The main characteristics of the gear-rim are its big diameter (often larger than 2 m) and the orientation of its teeth.
The gear-rims with teeth on the outer surface have the advantage of higher reduction ratios in combination with the pinions as well as reduced machining costs over the gear-rims with inner teeth.
See also
Wind turbine
Windmill
Yaw bearing
Yaw system
Wind power
Wind turbine design
Electric motor
Gearbox
References
Further reading
Wind Power Plants, R. Gasch and J. Twele, Solarpraxis,
Wind Energy Handbook, T. Burton [et al.], John Wiley & Sons, Ltd,
Aerodynamics
Electric power
Electrical generators
Electromechanical engineering
Energy conversion
Wind turbines | Yaw drive | Physics,Chemistry,Technology,Engineering | 708 |
479,771 | https://en.wikipedia.org/wiki/Correction%20fluid | A correction fluid is an opaque, usually white fluid applied to paper to mask errors in text. Once dried, it can be handwritten or handdrawn upon. It is typically packaged in small bottles, with lids attached to brushes (or triangular pieces of foam) that dip into the fluid. The brush applies the fluid to the paper.
Before the invention of word processors, correction fluid greatly facilitated the production of typewritten documents. One of the first forms of correction fluid was invented in 1956 by American secretary Bette Nesmith Graham, founder of Liquid Paper. With the advent of colored paper stocks for office use, manufacturers began producing their fluids in various matching colors, particularly reds, blues and yellows.
Composition
The exact composition of correction fluid varies between manufacturers, but most fluids are composed of an opacifying agent, a solvent (or thinner) and an adulterant 'fragrance' to discourage abuse. The opacifying agent can be composed of a mixture of titanium dioxide, latex, and other polymer resins.
Thinner originally contained toluene, which was banned due to its toxicity. Later, it contained 1,1,1-trichloroethane, a skin irritant now widely banned under the Montreal Protocol on Substances That Deplete the Ozone Layer, and then the slightly safer trichloroethylene. Thinners currently used with correction fluid include bromopropane. Because it contains organic solvents (volatile organic compounds), unused correction fluid thickens over time as volatile solvents escape into the air. It can become too thick to use, and sometimes completely solidifies. Therefore, some manufacturers also sell bottles of solvent as "thinner", a few drops of which will return the correction fluid to its original liquid state. To avoid the inconveniences of organic solvents (safety and availability), some brands of fluid are water-based. However, those have the disadvantages of a longer drying time, and incompatibility with some inks (which will soak through ).
Manufacture
Stainless steel tanks are used to hold or more. Specialists must consider the mixer and temperature control system carefully, and also the formula instructions, the correct types, and the amounts of raw materials at specified times by using computer controls. This process consists of 3 methods: firstly, compounding the batch; secondly, quality control check; and thirdly, filling and packing.
In the first phase, water will be filled into the main batch tank. The suspending agents and some of the ingredients will be added in this phase. Mixing is implemented at low rate for adequate dispersion. During the mixing, there is no air added into the mixture. In the second phase, pigment is in the process. It will be added in suitable amount into the water. Mixing is implemented at very high rate in this process which is different from the first phase. In the mixing process, when the particle is small enough, it will be added into the main batch. In the final phase, the resin and other necessary ingredients will be added such as colorants and preservatives.
In the process of checking the quality, specialists will check in the lab for physical and chemical characteristics such as pH determination, viscosity checks, appearance and odor evaluations. In case of mistake such as the ingredients are not enough for making correction fluid, this problem will be solved by adding more ingredients. When this process is finished, the correction fluid will be pumped to a holding tank waiting for filling the correction fluid in the next method.
Firstly, the filling process depends on the different package of each product. The filling line and the filling heads holding play a vital role in this process. The empty bottles will be in the conveyor belt and move continuously waiting for injecting correction fluid in each bottle. Secondly, when the filling process is finished, it comes to the packing process. All the filled bottles will be moved to the capping machine to sort the caps and tighten them. Finally, these bottles will be put into the box for shipping to the sellers and customers.
Marketing
Correction fluid is commonly referred to by the leading brand names as genericized. These brands include:
Cello (Correct-X)
Kores
Liquid Paper
Presto! by Pentel
Snopake
Tipp-Ex
Wite-Out
Health issues
Organic solvents are psychoactive when sufficient amounts are inhaled. Such solvents are common inhalants for adolescents due, in part, to the fact that they are inexpensive in comparison to other recreational drugs. Use of correction fluid as an inhalant can cause the heart to beat rapidly and irregularly, which can cause death. An unpleasant smell is added to some brands in order to deter abusers.
Companies have worked closely with authorities in order to ensure that all the warnings are duly mentioned on packaging (card and product labels) to inform parents and younger users of the risks associated with inhaling or drinking the fluid.
India has imposed a ban on the retail sale of bottled nail polish remover and bottled correction fluid, but permits its sale in devices that provide a small amount of the chemical in a container that dispenses it in a controlled way. The Ministry of Education also banned its use in schools in 2017. The manufacturer is required to affix a warning regarding the possible adverse effects on health if the material is inhaled.
See also
Correction paper
Correction tape
References
Correction instruments
Liquids | Correction fluid | Physics,Chemistry | 1,096 |
56,600,907 | https://en.wikipedia.org/wiki/Shellworld | A shellworld is any of several types of hypothetical megastructures:
A planet or a planetoid turned into series of concentric matryoshka doll-like layers supported by massive pillars. A shellworld of this type features prominently in Iain M. Banks' novel Matter.
A megastructure consisting of multiple layers of shells suspended above each other by orbital rings supported by hypothetical mass stream technology. This type of shellworld can be theoretically suspended above any type of stellar body, including planets, gas giants, stars and black holes. The most massive type of shellworld could be built around supermassive black holes at the center of galaxies.
An inflated canopy holding high pressure air around an otherwise airless world to create a breathable atmosphere. The pressure of the contained air supports the weight of the shell. This type of structure could also be built on top of an existing smaller planet or asteroid, enabling it to support human-friendly atmosphere.
Completely hollow shell worlds can also be created on a planetary or larger scale by contained gas alone, also called bubbleworlds, as long as the outward pressure from the contained gas balances the gravitational contraction of the entire structure, resulting in no net force on the shell. The scale is limited only by the mass of gas enclosed; the shell can be made of any mundane material. The shell can have an additional atmosphere on the outside.
References
External links
Shellworlds
Megastructures
Exploratory engineering
Terraforming | Shellworld | Technology,Engineering | 300 |
38,230,810 | https://en.wikipedia.org/wiki/AZ%20Canis%20Minoris | AZ Canis Minoris is a variable star in the equatorial constellation of Canis Minor. It is just visible to the naked eye in good viewing conditions as a dim, white-hued star with an apparent visual magnitude of around 6.46. The star is located around 500 light years away from the Sun based on parallax, and is drifting further away with a radial velocity of +15 km/s. No evidence has been found for a companion to this star, although in the past it has been reported as a binary star system.
This star has a stellar classification of A5 IV, matching an A-type subgiant star. The variable nature of this star was discovered in 1970 at Kitt Peak Observatory. It is a monoperiodic Delta Scuti variable with a cycle period of and an amplitude of 0.060 in visual magnitude; ranging from a peak magnitude of 6.44 down to 6.51. AZ Canis Minoris is nearly a billion years old with a projected rotational velocity of 44 km/s. It has 1.9 times the mass of the Sun and 3.8 times the Sun's radius. The star is radiating 48 times as much luminosity as the Sun from its photosphere at an effective temperature of 7,783 K.
References
A-type subgiants
Delta Scuti variables
Canis Minor
Durchmusterung objects
062437
037705
2989
Canis Minoris, AZ | AZ Canis Minoris | Astronomy | 301 |
772,923 | https://en.wikipedia.org/wiki/Rag%20doll | A rag doll is a doll made from scraps of fabric. They are one of the oldest children's toys in existence. Today, many rag dolls are commercially produced to mimic aspects of the original home-made dolls, such as simple features, soft cloth bodies, and patchwork clothing.
History
Traditionally home-made from (and stuffed with) spare scraps of material, they are one of the oldest children's toys in existence. The British Museum has a Roman rag doll, found in a child's grave dating from the 1st to 5th century AD. Historically, rag dolls have been used as comfort objects, and to teach young children nurturing skills. They were often used to teach children how to sew, as the children could practice sewing clothes for the doll and make some simple dolls themselves. In America, from the colonial era up to the early 20th century, children of various statuses would play with dolls made from rags or corn husks. Mass production of rag dolls began around 1830, when fabric color printing was first developed.
Types
Amish
Amish dolls are a type of traditional American rag dolls which originated as children's toys among the Old Order Amish people. These dolls commonly have no facial features.
Mexican
Slavic
Motanka dolls (Polish motanka, Ukrainian мо́танка, from motać/мотати - to tangle/spool/wind) are a type of traditional amulet dolls made in Poland, Ukraine and Belarus. They were a part of folk culture (Vasilisa the Beautiful) and its magical beliefs, made and tied without the use of a needle or other sharp objects, to "not poke/hurt the fate" and traditionally had no facial features, sometimes with a cross instead. Motanka dolls were made with specific intentions and wishes/tasks for them to grant, of various sorts, such as guarding the family or a prosperous marriage. Nowadays motanka dolls are coming back to popularity as a part of interest in Slavic cultures of the past, often as an educational device during educational and ethnographic workshops, or as a work of folk artists.
Commercially produced
Today, many rag dolls are commercially produced to mimic aspects of the original home-made dolls, such as simple features, soft cloth bodies, and patchwork clothing. One prominent example of a commercially produced ragdoll is the Raggedy Ann doll. Raggedy Ann first appeared in 1918 as the main character of a series of children's stories by Johnny Gruelle. Raggedy Andy, her brother, was introduced in 1920.
Traditional materials
In their earlier forms, rag dolls were made out of cloth scraps or cornhusks. In the 19th and 20th century, rag dolls were made out of stockinette, felt, or velvet.
See also
Stuffed toy
Lalaloopsy
References
Rag dolls
Textile arts
English folklore
Talismans
Amulets
Magic items
European witchcraft
Cunning folk | Rag doll | Physics | 593 |
32,180,016 | https://en.wikipedia.org/wiki/Calcium-activated%20potassium%20channel%20beta%20subunit | In molecular biology, the calcium-activated potassium channel beta subunit is a family of proteins comprising the beta subunits of calcium-activated potassium channels.
The functional diversity of potassium channels can arise through homo- or hetero-associations of alpha subunits or association with auxiliary cytoplasmic beta subunits. The beta subunit (which is thought to possess 2 transmembrane domains) increases the calcium sensitivity of the BK channel. It does this by enhancing the time spent by the channel in burst-like open states. However, it has little effect on the durations of closed intervals between bursts, or on the numbers of open and closed states entered during gating.
References
Protein families | Calcium-activated potassium channel beta subunit | Biology | 139 |
70,731,025 | https://en.wikipedia.org/wiki/5%2C6-Dibromo-DMT | 5,6-Dibromo-DMT (5,6-Dibromo-N,N-dimethyltryptamine, 5,6-Br-DMT) is a substituted tryptamine alkaloid found in some marine sponges. It is briefly mentioned in Alexander Shulgin's book TiHKAL (Tryptamines I Have Known and Loved) under the DMT entry and is stated to be found, along with other tryptamines, in Smenospongia aurea and other sponges.
See also
5,6-Dibromo-N-methyltryptamine
6-Bromotryptamine
5-Bromo-DMT
References
Tryptamine alkaloids
Bromoarenes
Dimethylamino compounds | 5,6-Dibromo-DMT | Chemistry | 162 |
36,957,127 | https://en.wikipedia.org/wiki/Broodiness | Broodiness is the action or behavioral tendency to sit on a clutch of eggs to incubate them, often requiring the non-expression of many other behaviors including feeding and drinking. Being broody has been defined as "Being in a state of readiness to brood eggs that is characterized by cessation of laying and by marked changes in behavior and physiology". Broodiness is usually associated with female birds, although males of some bird species become broody and some non-avian animals also show broodiness.
In wild birds
In wild birds, egg incubation is a normal and essential phase in the process of reproduction, and in many families of birds, e.g. pigeons, the eggs are incubated by both male and female parents.
Broodiness in males
In all species of phalaropes, the males become broody rather than the female. The females leave the nest after finishing laying to let the males incubate the eggs and take care of the young. Male emus (Dromaius novaehollandiae) become broody after their mates start laying, and begin to incubate the eggs before the laying period is complete.
Non-broodiness
A small number of atypical birds such as Passeriformes of the genus Molothrus (cowbirds) do not become broody but lay their eggs in the nests of other species for incubation, known as brood parasitism. The Australian brushturkey (Alectura lathami) also does not become broody, rather, it covers the eggs with a large mound of vegetable matter, which decomposes, keeping the eggs warm until hatching. The crab-plover, (Dromas ardeola), which lives on the coasts and islands of the Indian Ocean, lets its eggs incubate primarily by the heat of the sun, and will leave its nest unattended, occasionally for days at a time.
In domestic poultry
Broody hens can be recognized by their behaviour. They sit firmly over the eggs, and when people approach or try to remove the eggs, threaten the person by erecting their feathers, emitting a characteristic sound like clo-clo-clo and will peck aggressively. When broody, hens often temporarily cease eating or reduce their feed consumption.
Letting eggs accumulate in a relatively dark place near the floor often stimulates hens to become broody. Placing artificial eggs into nests also stimulates broodiness. Keeping hens in dark places with warm temperatures and in view of vocalising orphan chicks can induce broodiness, even in breeds that normally do not go broody.
Some environmental conditions stimulate broodiness. In heavy breeds of chickens, warm weather tends to bring about broodiness. Removing eggs each day, out of the sight of the hens, helps avoid broodiness not only in domestic poultry but also in some wild species in captivity. This continued egg laying means more eggs are laid than would occur under natural conditions. Poultry farming in battery cages also helps to avoid broodiness.
In commercial egg-laying
Because hens stop laying when they become broody, commercial poultry breeders perceive broodiness as an impediment to egg and poultry meat production. With domestication, it has become more profitable to incubate eggs artificially, while keeping hens in full egg production. To help achieve this, there has been intense artificial selection for non-broodiness in commercial egg laying chickens and parent stock of poultry. As a result of this artificial selection, broodiness has been reduced to very low levels in present-day breeds of commercial fowl, both among egg-laying and meat-producing breeds.
Physiological basis
Broodiness is due to the secretion of the hormone prolactin by the anterior lobe of the hypophysis. Prolactin injection in hens provokes egg laying to stop within a few days, vitellum reabsorption, ovary regression (hens only have a left ovary) and finally broodiness. However, attempts to stop broodiness by the administration of several hormones have failed because this state, once evoked, requires time to revert.
Prolactin injections inhibit the production of gonadotropin hormone, a hormone that stimulates ovarian follicles which is produced in the frontal lobe of hypophysis.
Castrated males can go broody with baby chicks, showing that broodiness is not limited to females, however, castrated males do not incubate eggs.
Contrary to common opinion, the temperature of broody hens barely differs from that of laying hens. Broody hens pluck feathers from their chest, using them to cover the eggs. As a consequence of this, they develop one or several patches of bare skin on the ventral surface. These reddish, well-vascularized areas of skin are usually called brood patches which improve heat transfer to the eggs.
Genetic basis
Broodiness is more common in some chicken breeds than others, indicating that it is a heritable characteristic. Breeds such as Cochin, Cornish and Silkie exhibit a tendency to broodiness, including brooding eggs from other species such as quails, pheasants, turkeys and geese. In some breeds such as the White Leghorn, broodiness is extremely rare.
Some studies on crosses of chicken breeds point to the hypothesis of complementary genes acting on broodiness. Other results point to the hypothesis of sex-linked genes, or, inheritance through the maternal chromosome. Although these studies have been made on different breeds of chickens, their results are not contradictory. There is common agreement that artificial selection for egg production succeeded in reducing the incidence of broody hens in chicken populations.
Chicken breeds that commonly exhibit broodiness
Chicken breeds that rarely exhibit broodiness
Broodiness in non-avian animals
There is some evidence that non-avian dinosaurs also practiced brooding. A specimen of the extinct Mongolian oviraptorid Citipati osmolskae was discovered in a chicken-like brooding position in 1993, which may indicate that they had begun using an insulating layer of feathers to keep the eggs warm.
Several deinonychosaur and oviraptorosaur specimens have also been found preserved on top of their nests, likely brooding in a bird-like manner.
Lungless salamanders in the family Plethodontidae lay a small number of eggs in a cluster among damp leaf litter. The female salamander often broods the eggs and in the genus Ensatinas, she has been observed to coil around them and press her throat area against them, effectively massaging them with a mucous secretion. The black mountain salamander mother broods her eggs, guarding them from predation as the larvae feed on the yolks of their eggs. They eventually break their way out of the egg capsules and disperse. Some species of Gymnophiona (caecilians, with long, cylindrical, limbless bodies) brood their eggs.
Most pythons coil around their egg-clutches and remain with them until they hatch. A female python will not leave the eggs, except to occasionally bask in the sun or drink water. She will even “shiver” to generate heat to incubate the eggs.
Some cichlid fish lay their eggs in the open, on rocks, leaves, or logs. Male and female parents usually engage in differing brooding roles. Most commonly, the male patrols the pair's territory and repels intruders, while females fan water over the eggs, removing the infertile and leading the fry while foraging. However, both sexes are able to perform the full range of parenting behaviours.
Mouthbrooding
Mouthbrooding, also known as oral incubation, refers to the care given by some groups of animals to fertilized eggs or their offspring by holding them in the mouth of the parent for extended periods of time. Although it has been observed in a variety of animals, most mouthbrooders are fish. The parent performing this behavior invariably feeds less often and afterwards will be underweight, requiring a period of feeding and restoring the depleted energy reserves.
Others
Marsupial frogs are so-called broody because they possess a dorsal brood pouch. In some species the eggs are fertilized on the female's lower back, and are inserted in her pouch with the aid of the male's toes. The eggs remain in contact with the female's vascular tissue, which provides them oxygen.
Some animals have a common name that includes the word 'brood' or its derivatives, although it is arguable whether the animals show 'broodiness' per se. For example, the female gastric-brooding frog (Rheobatrachus sp.) from Australia, now probably extinct, swallows her fertilized eggs, which then develop inside her stomach. She ceases to feed and stops secreting stomach acid and the tadpoles rely on the yolks of the eggs for nourishment. After six or seven weeks the mother opens her mouth wide and regurgitates the tadpoles which hop away from her mouth. The brooding sea anemone (Epiactis prolifera) is a colonial hermaphrodite that fertilizes and incubates its eggs internally. The motile larvae, after swimming out of the mouth, migrate down to the disk and become fixed there until they become little anemones, ready to move and feed independently.
In Darwin's frog (Rhinoderma darwinii), the female lays about 30 eggs and then the male guards them for about two weeks, until they hatch. The male then takes all the survivors and carries around the developing young in his vocal pouch. When the tiny tadpoles have developed they hop out and swim away. In this animal, the parents hold the hatched young rather than eggs in their mouths, so is arguably not showing 'broodiness'.
See also
Bee brood
Brood parasite
Brood patch
Nesting instinct
Allomothering
References
Aviculture
Poultry
Ethology
Oology | Broodiness | Biology | 2,055 |
47,452,370 | https://en.wikipedia.org/wiki/Suillus%20subaureus | Suillus subaureus is a rare species of bolete fungus in the family Suillaceae. It is found in North America, where it associates with deciduous trees. Originally described in 1887 by Charles Horton Peck, it was transferred to genus Suillus by Wally Snell in 1944. Fruitbodies are pale yellow—reflecting its specific epithet subaureus, which means "somewhat golden yellow". The spore print is olive brown. Spores are smooth and inamyloid, and measure 7–10 by 2.7–3.5 μm. It has also been recorded in Taiwan.
A recent study of this species indicates that S. subaureus associates with both deciduous and conifer trees in eastern North American forests. The spores of S. subaureus will not germinate in the presence of only deciduous tree roots. Instead, they require the presence of a conifer host tree (preferably Pinus) to germinate, but will then colonize and persist on deciduous hosts via mycelial extension.
The species is edible.
See also
List of North American boletes
References
External links
subaureus
Edible fungi
Fungi described in 1887
Fungi of Asia
Fungi of North America
Taxa named by Charles Horton Peck
Fungus species | Suillus subaureus | Biology | 251 |
71,428,969 | https://en.wikipedia.org/wiki/Yuri%20Struchkov | Yuri Timofeevich Struchkov () (28 July 1926, Moscow — 16 August 1995, Charleston, South Carolina) was a Russian and Soviet chemist. He was a prominent scientist in the field X-ray crystallography, a Corresponding Member of the Russian Academy of Sciences (1990) and the vice-president of the International Union of Crystallography (1993-1995). Struchkov was the founder and the first Director of the X-Ray Structural Laboratory of Nesmeyanov Institute of Organoelement Compounds and X-Ray Structural Centre of the Russian Academy of Sciences (RAS). He made important contributions to the fields of chemistry and crystallography of organic, organoelement and coordination compounds. As an author and co-author of more than 1000 papers, published between 1980 and 1990, he became the most widely published scientist of the decade. In 2021, the International Union of Crystallography (IUCr) honored his contributions to the field of small molecule structural crystallography, establishing the Struchkov Prize, which is awarded to the young crystallographers at the regular triennial IUCr International Congress of Crystallography.>
Scientific career
In 1948 Struchkov graduated from the MSU Faculty of Chemistry.
In 1948—1953 he was a working on his Ph.D. thesis under the supervision of professor A.I.Kitaigorodski.
In 1950 he joined the staff of the Zelinsky Institute of Organic Chemistry (IOCh).
In 1953 he defended the PhD thesis X-Ray structural study of two addition products of metal salts to unsaturated compounds.
In 1954—1995 he worked in the Nesmeyanov Institute of Organoelement Compounds (INEOS):
in the laboratory headed by A.I.Kitaigorodski (1954-1973)
in the diffraction studies group (1973-1977)
in the new Laboratory of the X-Ray Structure Analysis (LXRSA) which was founded and headed by him (1977-1995).
In 1989 Struchkov became the Director of the X-Ray Structural Centre of RAS, which was based on the INEOS LXRSA.
In 1990 he was elected Corresponding Member of RAS and a member of the executive committee of the International Union of Crystallography (IUCr).
At the XVI General Assembly of IUCr in 1993 he became the vice-president of the IUCr (1993-1995).
References
1926 births
1995 deaths
Soviet chemists
20th-century Russian chemists
Crystallographers
Ig Nobel laureates | Yuri Struchkov | Chemistry,Materials_science | 535 |
4,065,640 | https://en.wikipedia.org/wiki/CRC%20Oil%20Storage%20Depot | CRC Oil Storage Depot was one of five oil terminals in Hong Kong and owned by China Resources Petroleum Company Limited (CRC).
See also
Energy in Hong Kong
References
External links
Texaco Oil Depot [1936-1988]. Contains a list of former oil depots in Hong Kong.
Tsing Yi
Oil terminals
Energy infrastructure in Hong Kong | CRC Oil Storage Depot | Chemistry | 70 |
7,741,863 | https://en.wikipedia.org/wiki/Commutative%20magma | In mathematics, there exist magmas that are commutative but not associative. A simple example of such a magma may be derived from the children's game of rock, paper, scissors. Such magmas give rise to non-associative algebras.
A magma which is both commutative and associative is a commutative semigroup.
Example: rock, paper, scissors
In the game of rock paper scissors, let , standing for the "rock", "paper" and "scissors" gestures respectively, and consider the binary operation derived from the rules of the game as follows:
For all :
If and beats in the game, then
I.e. every is idempotent.
So that for example:
"paper beats rock";
"scissors tie with scissors".
This results in the Cayley table:
By definition, the magma is commutative, but it is also non-associative, as shown by:
but
i.e.
It is the simplest non-associative magma that is conservative, in the sense that the result of any magma operation is one of the two values given as arguments to the operation.
Applications
The arithmetic mean, and generalized means of numbers or of higher-dimensional quantities, such as Frechet means, are often commutative but non-associative.
Commutative but non-associative magmas may be used to analyze genetic recombination.
References
Non-associative algebra | Commutative magma | Mathematics | 314 |
2,476,693 | https://en.wikipedia.org/wiki/List%20of%20Croton%20sections | The sections and subsections of the genus Croton:
sect. Cleodora (Klotzsch) Baill.?
sect. Cyclostigma Griseb.
subsect. Cyclostigma (Griseb.) Müll. Arg.
subsect. Sampatik G.L.Webster
subsect. Palanostigma Mart. ex Baill.
sect. Klotzschiphytum (Baill.) Baill.
sect. Eutropia (Klotzsch) Baill.
sect. Luntia (Raf.) G.L. Webster
subsect. Cuneati G.L. Webster
subsect. Matourenses G.L. Webster
sect Eluteria Griseb.
sect. Croton
sect. Ocalia (Klotzsch) Baill.
sect. Corylocroton G.L.Webster
sect. Anadenocroton G.L.Webster
sect. Tiglium (Klotzsch) Baill.
sect. Quadrilobus Müll. Arg.
sect. Cascarilla Griseb.
sect. Velamea Baill.
sect. Andrichnia Baill.
sect. Anisophyllum Baill.
sect. Furcaria Boivin ex Baill.
sect. Monguia Baill.
sect. Decapetalon Müll. Arg.
sect. Podostachys (Klotzsch) Baill.
sect. Octolobium Chodat & Hassl.
sect. Geiseleria (Klotzsch) Baill.
sect. Pilinophyton (Klotzsch) A. Gray
sect. Eremocarpus (Benth.) G.L.Webster
sect. Gynamblosis (Torr.) A. Gray
sect. Crotonopsis (Michx.) G.L.Webster
sect. Argyrocroton (Müll. Arg.) G.L.Webster
sect. Lamprocroton (Müll. Arg.) Pax
sect. Julocroton (Mart.) G.L.Webster
sect. Adenophyllum Griseb.
sect. Barhamia (Klotzsch) Baill.
sect. Decalobium Müll. Arg.
sect. Micranthis Baill.
sect. Medea (Klotzsch) Baill.
sect. Lasiogyne (Klotzsch) Baill.
sect. Argyroglossum Baill.
sect. Astraeopsis Baill.
sect. Codonacalyx Klotzsch ex Baill.
sect. Astraea (Klotzsch) Baill.
sect. Drepadenium (Raf.) Müll. Arg.
References
Taxonomic lists
Plant sections | List of Croton sections | Biology | 596 |
2,297,929 | https://en.wikipedia.org/wiki/Closure%20with%20a%20twist | Closure with a twist is a property of subsets of an algebraic structure. A subset of an algebraic structure is said to exhibit closure with a twist if for every two elements
there exists an automorphism of and an element such that
where "" is notation for an operation on preserved by .
Two examples of algebraic structures which exhibit closure with a twist are the cwatset and the generalized cwatset, or GC-set.
Cwatset
In mathematics, a cwatset is a set of bitstrings, all of the same length, which is closed with a twist.
If each string in a cwatset, C, say, is of length n, then C will be a subset of . Thus, two strings in C are added by adding the bits in the strings modulo 2 (that is, addition without carry, or exclusive disjunction). The symmetric group on n letters, , acts on by bit permutation:
where is an element of and p is an element of . Closure with a twist now means that for each element c in C, there exists some permutation such that, when you add c to an arbitrary element e in the cwatset and then apply the permutation, the result will also be an element of C. That is, denoting addition without carry by , C will be a cwatset if and only if
This condition can also be written as
Examples
All subgroups of — that is, nonempty subsets of which are closed under addition-without-carry — are trivially cwatsets, since we can choose each permutation pc to be the identity permutation.
An example of a cwatset which is not a group is
F = {000,110,101}.
To demonstrate that F is a cwatset, observe that
F + 000 = F.
F + 110 = {110,000,011}, which is F with the first two bits of each string transposed.
F + 101 = {101,011,000}, which is the same as F after exchanging the first and third bits in each string.
A matrix representation of a cwatset is formed by writing its words as the rows of a 0-1 matrix. For instance a matrix representation of F is given by
To see that F is a cwatset using this notation, note that
where and denote permutations of the rows and columns of the matrix, respectively, expressed in cycle notation.
For any another example of a cwatset is , which has -by- matrix representation
Note that for , .
An example of a nongroup cwatset with a rectangular matrix representation is
Properties
Let be a cwatset.
The degree of C is equal to the exponent n.
The order of C, denoted by |C|, is the set cardinality of C.
There is a necessary condition on the order of a cwatset in terms of its degree, which is
analogous to Lagrange's Theorem in group theory. To wit,
Theorem. If C is a cwatset of degree n and order m, then m divides .
The divisibility condition is necessary but not sufficient. For example, there does not exist a cwatset of degree 5 and order 15.
Generalized cwatset
In mathematics, a generalized cwatset (GC-set) is an algebraic structure generalizing the notion of closure with a twist, the defining characteristic of the cwatset.
Definitions
A subset H of a group G is a GC-set if for each , there exists a such that .
Furthermore, a GC-set H ⊆ G is a cyclic GC-set if there exists an and a such that where and for all .
Examples
Any cwatset is a GC-set, since implies that .
Any group is a GC-set, satisfying the definition with the identity automorphism.
A non-trivial example of a GC-set is where .
A nonexample showing that the definition is not trivial for subsets of is .
Properties
A GC-set H ⊆ G always contains the identity element of G.
The direct product of GC-sets is again a GC-set.
A subset H ⊆ G is a GC-set if and only if it is the projection of a subgroup of Aut(G)⋉G, the semi-direct product of Aut(G) and G.
As a consequence of the previous property, GC-sets have an analogue of Lagrange's Theorem: The order of a GC-set divides the order of Aut(G)⋉G.
If a GC-set H has the same order as the subgroup of Aut(G)⋉G of which it is the projection then for each prime power which divides the order of H, H contains sub-GC-sets of orders p,,...,. (Analogue of the first Sylow Theorem)
A GC-set is cyclic if and only if it is the projection of a cyclic subgroup of Aut(G)⋉G.
References
.
The Cwatset of a Graph, Nancy-Elizabeth Bush and Paul A. Isihara, Mathematics Magazine 74, #1 (February 2001), pp. 41–47.
On the symmetry groups of hypergraphs of perfect cwatsets, Daniel K. Biss, Ars Combinatorica 56 (2000), pp. 271–288.
Automorphic Subsets of the n-dimensional Cube, Gareth Jones, Mikhail Klin, and Felix Lazebnik, Beiträge zur Algebra und Geometrie 41 (2000), #2, pp. 303–323.
Daniel C. Smith (2003)RHIT-UMJ, RHIT
Abstract algebra | Closure with a twist | Mathematics | 1,180 |
2,782,166 | https://en.wikipedia.org/wiki/U%20Antliae | U Antliae (U Ant) is a variable star in the constellation Antlia. It is a carbon star surrounded by two thin shells of dust.
U Antliae is an extremely red C-type carbon star. These cool stars on the asymptotic giant branch are further reddened by strong mass loss and dust that forms around the star. U Antliae is calculated to have an effective surface temperature of , although the light that reaches us has an appearance more like that from a black body with a temperature of surrounded by dust at a temperature of . It emits most of its radiation in the infrared and although it is only about 500 times brighter than the sun at visual wavelengths, its bolometric luminosity is 8,000 times higher than the Sun's.
In 1901, Louisa Dennison Wells discovered that the brightness of the star varied, from the examination of photographic plates. Annie Jump Cannon included the star, with its variable star designation U Antiliae, in her 1907 Second Catalogue of Variable Stars.
U Antliae is an irregular variable star with an apparent magnitude that varies between 5.27 and 6.04. Approximately 900 light years from Earth, it is surrounded by two shells of dust, thought to have been ejected 14,000 and 10,000 years ago. The exact origin and structure of the shells is uncertain, possibly due to enhanced mass loss during thermal pulses, possibly due to interaction of the stellar wind with interstellar material.
Notes
References
Slow irregular variables
091793
Antlia
Carbon stars
Antliae, U
051821
4153
Asymptotic-giant-branch stars
Durchmusterung objects | U Antliae | Astronomy | 338 |
3,708,060 | https://en.wikipedia.org/wiki/Solvent%20exposure | Solvent exposure occurs when a chemical, material, or person comes into contact with a solvent. Chemicals can be dissolved in solvents, materials such as polymers can be broken down chemically by solvents, and people can develop certain ailments from exposure to solvents both organic and inorganic.
Some common solvents include acetone, methanol, tetrahydrofuran, dimethylsulfoxide, and water among countless others.
In biology, the solvent exposure of an amino acid in a protein measures to what extent the amino acid is accessible to the solvent (usually water) surrounding the protein. Generally speaking, hydrophobic amino acids will be buried inside the protein and thus shielded from the solvent, while hydrophilic amino acids will be close to the surface and thus exposed to the solvent. However, as with many biological rules exceptions are common and hydrophilic residues are frequently found to be buried in the native structure and vice versa.
Solvent exposure can be numerically described by several measures, the most popular measures being accessible surface area and relative accessible surface area. Other measures are for example:
Contact number: number of amino acid neighbors within a sphere around the amino acid.
Residue depth: distance of the amino acid to the molecular surface.
Half sphere exposure: number of amino acid neighbors within two half spheres around the amino acid.
References
Lee B, Richards F. (1971) The interpretation of protein structures: estimation of static accessibility. J. Mol. Biol. 55:379-400
Greer J, Bush B. (1978) Macromolecular shape and surface maps by solvent exclusion. Proc. Natl. Acad. Sci. USA 75:303-307.
Connolly M. (1983) Solvent-accessible surfaces of proteins and nucleic acids. Science 221:709-713
Chakravarty S, Varadarajan R. (1999) Residue depth: a novel parameter for the analysis of protein structure and stability. Structure Fold. Des. 7:723-732.
Pintar A, Carugo O, Pongor S. (2003) Atom depth in protein structure and function. Trends Biochem. Sci. 28:593-597.
Hamelryck T. (2005) An amino acid has two sides: A new 2D measure provides a different view of solvent exposure. Proteins Struct. Func. Bioinf. 59:38-48.
Amino acids
Nitrogen cycle
Solvents | Solvent exposure | Chemistry | 504 |
988,796 | https://en.wikipedia.org/wiki/Jevons%20paradox | In economics, the Jevons paradox (; sometimes Jevons effect) occurs when technological progress increases the efficiency with which a resource is used (reducing the amount necessary for any one use), but the falling cost of use induces increases in demand enough that resource use is increased, rather than reduced. Governments, both historical and modern, typically expect that energy efficiency gains will lower energy consumption, rather than expecting the Jevons paradox.
In 1865, the English economist William Stanley Jevons observed that technological improvements that increased the efficiency of coal use led to the increased consumption of coal in a wide range of industries. He argued that, contrary to common intuition, technological progress could not be relied upon to reduce fuel consumption.
The issue has been re-examined by modern economists studying consumption rebound effects from improved energy efficiency. In addition to reducing the amount needed for a given use, improved efficiency also lowers the relative cost of using a resource, which increases the quantity demanded. This may counteract (to some extent) the reduction in use from improved efficiency. Additionally, improved efficiency increases real incomes and accelerates economic growth, further increasing the demand for resources. The Jevons paradox occurs when the effect from increased demand predominates, and the improved efficiency results in a faster rate of resource utilization.
Considerable debate exists about the size of the rebound in energy efficiency and the relevance of the Jevons paradox to energy conservation. Some dismiss the effect, while others worry that it may be self-defeating to pursue sustainability by increasing energy efficiency. Some environmental economists have proposed that efficiency gains be coupled with conservation policies that keep the cost of use the same (or higher) to avoid the Jevons paradox. Conservation policies that increase cost of use (such as cap and trade or green taxes) can be used to control the rebound effect.
History
The Jevons paradox was first described by the English economist William Stanley Jevons in his 1865 book The Coal Question. Jevons observed that England's consumption of coal soared after James Watt introduced the Watt steam engine, which greatly improved the efficiency of the coal-fired steam engine from Thomas Newcomen's earlier design. Watt's innovations made coal a more cost-effective power source, leading to the increased use of the steam engine in a wide range of industries. This in turn increased total coal consumption, even as the amount of coal required for any particular application fell. Jevons argued that improvements in fuel efficiency tend to increase (rather than decrease) fuel use, writing: "It is a confusion of ideas to suppose that the economical use of fuel is equivalent to diminished consumption. The very contrary is the truth."
At that time, many in Britain worried that coal reserves were rapidly dwindling, but some experts opined that improving technology would reduce coal consumption. Jevons argued that this view was incorrect, as further increases in efficiency would tend to increase the use of coal. Hence, improving technology would tend to increase the rate at which England's coal deposits were being depleted, and could not be relied upon to solve the problem.
Although Jevons originally focused on coal, the concept has since been extended to other resources, e.g., water usage. The Jevons paradox is also found in socio-hydrology, in the safe development paradox called the reservoir effect, where construction of a reservoir to reduce the risk of water shortage can instead exacerbate that risk, as increased water availability leads to more development and hence more water consumption.
Cause
Economists have observed that consumers tend to travel more when their cars are more fuel efficient, causing a 'rebound' in the demand for fuel. An increase in the efficiency with which a resource (e.g. fuel) is used causes a decrease in the cost of using that resource when measured in terms of what it can achieve (e.g. travel). Generally speaking, a decrease in the cost (or price) of a good or service will increase the quantity demanded (the law of demand). With a lower cost for travel, consumers will travel more, increasing the demand for fuel. This increase in demand is known as the rebound effect, and it may or may not be large enough to offset the original drop in fuel use from the increased efficiency. The Jevons paradox occurs when the rebound effect is greater than 100%, exceeding the original efficiency gains.
The size of the direct rebound effect is dependent on the price elasticity of demand for the good. In a perfectly competitive market where fuel is the sole input used, if the price of fuel remains constant but efficiency is doubled, the effective price of travel would be halved (twice as much travel can be purchased). If in response, the amount of travel purchased more than doubles (i.e. demand is price elastic), then fuel consumption would increase, and the Jevons paradox would occur. If demand is price inelastic, the amount of travel purchased would less than double, and fuel consumption would decrease. However, goods and services generally use more than one type of input (e.g. fuel, labour, machinery), and other factors besides input cost may also affect price. These factors tend to reduce the rebound effect, making the Jevons paradox less likely to occur.
Khazzoom–Brookes postulate
In the 1980s, economists Daniel Khazzoom and Leonard Brookes revisited the Jevons paradox for the case of society's energy use. Brookes, then chief economist at the UK Atomic Energy Authority, argued that attempts to reduce energy consumption by increasing energy efficiency would simply raise demand for energy in the economy as a whole. Khazzoom focused on the narrower point that the potential for rebound was ignored in mandatory performance standards for domestic appliances being set by the California Energy Commission.
In 1992, the economist Harry Saunders dubbed the hypothesis that improvements in energy efficiency work to increase (rather than decrease) energy consumption the Khazzoom–Brookes postulate, and argued that the hypothesis is broadly supported by neoclassical growth theory (the mainstream economic theory of capital accumulation, technological progress and long-run economic growth). Saunders showed that the Khazzoom–Brookes postulate occurs in the neoclassical growth model under a wide range of assumptions.
According to Saunders, increased energy efficiency tends to increase energy consumption by two means. First, increased energy efficiency makes the use of energy relatively cheaper, thus encouraging increased use (the direct rebound effect). Second, increased energy efficiency increases real incomes and leads to increased economic growth, which pulls up energy use for the whole economy. At the microeconomic level (looking at an individual market), even with the rebound effect, improvements in energy efficiency usually result in reduced energy consumption. That is, the rebound effect is usually less than 100%. However, at the macroeconomic level, more efficient (and hence comparatively cheaper) energy leads to faster economic growth, which increases energy use throughout the economy. Saunders argued that taking into account both microeconomic and macroeconomic effects, the technological progress that improves energy efficiency will tend to increase overall energy use.
Energy conservation policy
Jevons warned that fuel efficiency gains tend to increase fuel use. However, this does not imply that improved fuel efficiency is worthless if the Jevons paradox occurs; higher fuel efficiency enables greater production and a higher material quality of life. For example, a more efficient steam engine allowed the cheaper transport of goods and people that contributed to the Industrial Revolution. Nonetheless, if the Khazzoom–Brookes postulate is correct, increased fuel efficiency, by itself, will not reduce the rate of depletion of fossil fuels.
There is considerable debate about whether the Khazzoom-Brookes Postulate is correct, and of the relevance of the Jevons paradox to energy conservation policy. Most governments, environmentalists and NGOs pursue policies that improve efficiency, holding that these policies will lower resource consumption and reduce environmental problems. Others, including many environmental economists, doubt this 'efficiency strategy' towards sustainability, and worry that efficiency gains may in fact lead to higher production and consumption. They hold that for resource use to fall, efficiency gains should be coupled with other policies that limit resource use. However, other environmental economists argue that, while the Jevons paradox may occur in some situations, the empirical evidence for its widespread applicability is limited.
The Jevons paradox is sometimes used to argue that energy conservation efforts are futile, for example, that more efficient use of oil will lead to increased demand, and will not slow the arrival or the effects of peak oil. This argument is usually presented as a reason not to enact environmental policies or pursue fuel efficiency (e.g. if cars are more efficient, it will simply lead to more driving). Several points have been raised against this argument. First, in the context of a mature market such as for oil in developed countries, the direct rebound effect is usually small, and so increased fuel efficiency usually reduces resource use, other conditions remaining constant. Second, even if increased efficiency does not reduce the total amount of fuel used, there remain other benefits associated with improved efficiency. For example, increased fuel efficiency may mitigate the price increases, shortages and disruptions in the global economy associated with crude oil depletion. Third, environmental economists have pointed out that fuel use will unambiguously decrease if increased efficiency is coupled with an intervention (e.g. a fuel tax) that keeps the cost of fuel use the same or higher.
The Jevons paradox indicates that increased efficiency by itself may not reduce fuel use, and that sustainable energy policy must rely on other types of government interventions as well. As the imposition of conservation standards or other government interventions that increase cost-of-use do not display the Jevons paradox, they can be used to control the rebound effect. To ensure that efficiency-enhancing technological improvements reduce fuel use, efficiency gains can be paired with government intervention that reduces demand (e.g. green taxes, cap and trade, or higher emissions standards). The ecological economists Mathis Wackernagel and William Rees have suggested that any cost savings from efficiency gains be "taxed away or otherwise removed from further economic circulation. Preferably they should be captured for reinvestment in natural capital rehabilitation." By mitigating the economic effects of government interventions designed to promote ecologically sustainable activities, efficiency-improving technological progress may make the imposition of these interventions more palatable, and more likely to be implemented.
Other examples
Agriculture
Increasing the yield of a crop, such as wheat, for a given area will reduce the area required to achieve the same total yield. However, increasing efficiency may make it more profitable to grow wheat and lead farmers to convert land to the production of wheat, thereby increasing land use instead.
AI, Large Language Models, and Semiconductors
Improvements in AI model efficiency have demonstrated the Jevons paradox in the computing sector. When OpenAI introduced their advanced ChatGPT Pro model in 2024 at $200 per month, featuring 86% accuracy on competition math problems (compared to 78% for their standard model), the higher performance led to increased rather than decreased compute consumption. Despite the higher price point and improved efficiency, organizations began implementing AI automation more extensively, particularly in data science, programming, and case law analysis. This trend was evidenced by OpenRouter's data, which showed an increase from 8 billion to over 300 billion tokens per week in token consumption within a year. The improved efficiency of these models, rather than reducing overall compute usage, enabled new use cases like continuous-operation AI agents and automated workflows, leading to higher total semiconductor demand for companies like TSMC, Intel, and Samsung.
See also
Andy and Bill's law, new software will always consume any increase in computing power that new hardware can provide
Diminishing returns
Downs–Thomson paradox, increasing road capacity can make traffic congestion worse
Tragedy of the commons, a phenomenon in which common resources to which access is not regulated tend to become depleted
Wirth's law, faster hardware can trigger the development of less-efficient software
Dutch Disease, strong revenue from a dominant sector renders other sectors uncompetitive and starves them
AI boom, periods of increased investment and rapid advancement in artificial intelligence technology
References
Further reading
Eponymous paradoxes
Paradoxes in economics
Industrial ecology
Energy policy
Energy conservation
Environmental social science concepts | Jevons paradox | Chemistry,Engineering,Environmental_science | 2,508 |
5,750,245 | https://en.wikipedia.org/wiki/PropBank | PropBank is a corpus that is annotated with verbal propositions and their arguments—a "proposition bank". Although "PropBank" refers to a specific corpus produced by Martha Palmer et al., the term propbank is also coming to be used as a common noun referring to any corpus that has been annotated with propositions and their arguments.
The PropBank project has played a role in recent research in natural language processing, and has been used in semantic role labelling.
Comparison
PropBank differs from FrameNet, the resource to which it is most frequently compared, in several ways.
PropBank is a verb-oriented resource, while FrameNet is centered on the more abstract notion of frames, which generalizes descriptions across similar verbs (e.g. "describe" and "characterize") as well as nouns and other words (e.g. "description"). PropBank does not annotate events or states of affairs described using nouns. PropBank commits to annotating all verbs in a corpus, whereas the FrameNet project chooses sets of example sentences from a large corpus and only in a few cases has annotated longer continuous stretches of text.
PropBank-style annotations often remain close to the syntactic level, while FrameNet-style annotations are sometimes more semantically motivated. From the start, PropBank was developed with the idea of serving as training data for machine learning-based semantic role labeling systems in mind. It requires that all arguments to a verb be syntactic constituents and different senses of a word are only distinguished if the differences bear on the arguments. Due to such differences, semantic role labeling with respect to PropBank is often a somewhat easier task than producing FrameNet-style annotations.
See also
VerbNet
FrameNet
References
External links
PropBank website
NomBank website
SALSA website
Computational linguistics
Corpora
Natural language processing
Linguistic research | PropBank | Technology | 388 |
16,131,177 | https://en.wikipedia.org/wiki/Watari%20Museum%20of%20Contemporary%20Art | The , commonly referred to as Watari-um, is a museum of contemporary art located in Shibuya, Tokyo. Founded by Shizuko Watari and opened in 1990, the museum is near Gaienmae Station on the Tokyo Metro Ginza Line.
The institution promotes conceptual art and other non-commercial artists in Japan. It began as a commercial venue known as the Galerie Watari, which showcased a range of artists such as Sol LeWitt and Nam June Paik, as well as famous pop artists Andy Warhol and Keith Haring.
The Watari-um became noted for its exhibitions of international and Japanese artists, while also reflecting on the position of Japanese art in the international context. The museum also organizes lectures, learning workshops for children, and small project room exhibitions.
History
From 1972 to 1989, Shizuko Watari was the director of the Galerie Watari in Tokyo, which organized exhibitions for Japanese and international artists including Nam June Paik, Keith Haring, Marcel Broodthaers, On Kawara and Shinro Ohtake.
The gallery was expanded and became the Watari Museum of Contemporary Art. Is also known as the Watari-um, which derives from the combination of Watari and museum. The 6-story museum was designed by Swiss architect Mario Botta and opened in September 1990. The first floor is devoted entirely to the museum shop. The fourth floor offers a bird’s eye view of works displayed below, and the glass-walled mezzanine of the third floor makes for visual correspondence between artworks displayed in the exhibition rooms of the art gallery. The top floors accommodate the offices and the owner's residence.
Beginning with an exhibition of Joseph Beuys in 1991, the Watari-um became noted for its exhibitions of significant international artists. The institution also helped to establish connections between Japanese and Asian artists, through projects such as Chinese Contemporary Art 1997, which included a large-scale performance by Zhang Huan.
Large retrospective exhibitions of the artists Larry Clark, Henry Darger, Jan Fabre, Federico Herrero, Mike Kelley, John Lurie, Barry McGee, Gerda Steiner & Jörg Lenzlinger, have been held at the museum over the last few decades.
References
External links
Official website—
Art museums and galleries in Tokyo
Contemporary art galleries in Japan
Buildings and structures in Shibuya
Art museums and galleries established in 1990
Buildings and structures completed in 1990
1990 establishments in Japan
Mario Botta buildings
Modernist architecture in Japan
Postmodern architecture | Watari Museum of Contemporary Art | Engineering | 503 |
26,953,377 | https://en.wikipedia.org/wiki/Triflyl%20group | In organic chemistry, the triflyl group (systematic name: trifluoromethanesulfonyl group) is a functional group with the formula and structure . The triflyl group is often represented by –Tf.
The related triflate group (trifluoromethanesulfonate) has the formula , and is represented by –OTf.
See also
Triflyl azide, TfN3
Trioctylmethylammonium bis(trifluoromethylsulfonyl)imide,
Comins' reagent
Bis(trifluoromethanesulfonyl)aniline
Triflic anhydride (CF3SO2)2O is a very strong triflating agent.
References
Triflyl compounds
Functional groups | Triflyl group | Chemistry | 167 |
25,811,021 | https://en.wikipedia.org/wiki/Palau%27amine | Palau'amine is a toxic chlorinated alkaloid compound synthesized naturally by certain species of sea sponges. The name of the molecule derives from the island nation of Palau, near where the first sponge species discovered to produce it, Stylotella agminata, is found. It has since been isolated in other sponges, including Stylissa massa.
The substance was first isolated from Stylotella agminata, a sponge found in the southwest Pacific Ocean, and described in 1993. Containing nine nitrogen atoms, the molecule is considered highly complex. The precise atomic structure was pinned down in 2007, and two years later, the molecule was synthesized in the lab of Phil Baran at the Scripps Research Institute in La Jolla, California. Early efforts towards its synthesis were directed at a misassigned structure featuring a cis- rather than trans-5/5 ring fusion, an error that was made because the trans-5/5 ring system is some 6 kcal/mol less stable than the cis-configured system.
Biomimetic synthesis
Based on the hypothesized biosynthesis of palau'amine, a proposed pathway to this dimeric pyrrole-imidazole alkaloid includes a key oxidation of a β-ketoester with manganese(III) acetate to initiate a cascade radical cyclization, producing an ageliferin skeleton.
Biological effects
Palau'amine is a proteasome inhibitor.
References
Alkaloids
Organochlorides
Halogen-containing alkaloids
Guanidine alkaloids
Amines
Spiro compounds
Nitrogen heterocycles
Proteasome inhibitors | Palau'amine | Chemistry | 346 |
993 | https://en.wikipedia.org/wiki/Analog%20signal | An analog signal (American English) or analogue signal (British and Commonwealth English) is any continuous-time signal representing some other quantity, i.e., analogous to another quantity. For example, in an analog audio signal, the instantaneous signal voltage varies continuously with the pressure of the sound waves.
In contrast, a digital signal represents the original time-varying quantity as a sampled sequence of quantized values. Digital sampling imposes some bandwidth and dynamic range constraints on the representation and adds quantization noise.
The term analog signal usually refers to electrical signals; however, mechanical, pneumatic, hydraulic, and other systems may also convey or be considered analog signals.
Representation
An analog signal uses some property of the medium to convey the signal's information. For example, an aneroid barometer uses rotary position as the signal to convey pressure information. In an electrical signal, the voltage, current, or frequency of the signal may be varied to represent the information.
Any information may be conveyed by an analog signal; such a signal may be a measured response to changes in a physical variable, such as sound, light, temperature, position, or pressure. The physical variable is converted to an analog signal by a transducer. For example, sound striking the diaphragm of a microphone induces corresponding fluctuations in the current produced by a coil in an electromagnetic microphone or the voltage produced by a condenser microphone. The voltage or the current is said to be an analog of the sound.
Noise
An analog signal is subject to electronic noise and distortion introduced by communication channels, recording and signal processing operations, which can progressively degrade the signal-to-noise ratio (SNR). As the signal is transmitted, copied, or processed, the unavoidable noise introduced in the signal path will accumulate as a generation loss, progressively and irreversibly degrading the SNR, until in extreme cases, the signal can be overwhelmed. Noise can show up as hiss and intermodulation distortion in audio signals, or snow in video signals. Generation loss is irreversible as there is no reliable method to distinguish the noise from the signal.
Converting an analog signal to digital form introduces a low-level quantization noise into the signal due to finite resolution of digital systems. Once in digital form, the signal can be transmitted, stored, and processed without introducing additional noise or distortion using error detection and correction.
Noise accumulation in analog systems can be minimized by electromagnetic shielding, balanced lines, low-noise amplifiers and high-quality electrical components.
See also
Amplifier
Analog computer
Analog device
Analog signal processing
Magnetic tape
Preamplifier
References
Further reading
Analog circuits
Electronic design
Television terminology
Video signal | Analog signal | Engineering | 549 |
10,893,579 | https://en.wikipedia.org/wiki/Clavibacter%20michiganensis | Clavibacter michiganensis is an aerobic non-sporulating Gram-positive plant pathogenic actinomycete of the genus Clavibacter. Clavibacter michiganensis has several subspecies. Clavibacter michiganensis subsp. michiganensis causes substantial economic losses worldwide by damaging tomatoes and potatoes.
Context
Clavibacter michiganensis, also known as Ring Rot, is an unusual genus of phytopathogenic bacteria in that it is gram-positive and does not have a type three secretion system. All Clavibacter species and subspecies have a type B2γ cell wall crosslinked at a diaminobutyrate residue. Clavibacter is an aerobic bacterium with a coryneform morphology. There is no mycelium and no spores are produced.
Clavibacter michiganensis infects the primary host in one of three ways: wounds, hydathodes, or by contaminated seed. If the bacteria reach a suitable quorum, the result is a systemic vascular infection. In the first stages of invasion, C. michiganensis resides as a biotrophic pathogen in the xylem vessels.
Clavibacter has a complex history of taxonomical names. For a long time, there was only one recognized species within the genus Clavibacter. There are nine subspecies within the michiganensis species. Recently, some strains have been reclassified into other genera. This complex history stems from the difficulty in characterizing bacteria. Unlike fungi, the morphology of bacteria is not very sufficient for taxonomical purposes. To this end, strains of a phytopathogenic bacteria, called pathovars, are distinguished by cultural (selective media), physiological, biochemical (e.g. secreted enzymes the chemical responses of the plant), or pathological characteristics (including the range of susceptible hosts).
Recently, two strains of this bacteria – subsp. sepidonicum and subsp. michiganensis – have had their genomes sequenced and annotated. There is still much to discover about this pathogen-host interaction but now that the genome has been sequenced, the rate of discoveries will likely increase. One of the main goals pertaining to research of these bacterial genomes is to develop resistant varieties. Unfortunately, no resistant varieties have yet been found.
Genetics
The species has a single chromosome.
C. m. subsp. michiganensis
C. m. subsp. michiganensis is the causative agent of bacterial wilt and canker of tomato (Lycopersicon esculentum).
Hosts and symptoms
When the infection occurs in an early stage of the tomato plant there may be wilting on leaves because Clavibacter michiganensis subsp. michiganensis enter the plant by wounds, including root wounds, and if the bacterium gets to the xylem then a systemic infection is likely that may plug the xylem vessels. The wilting may only show on one side of the leaf and may recover during cooler periods. The entire system of xylem within the plant allows the bacteria to form titers of up to 109 bacteria per gram of plant tissue. Wilting may eventually spread to all leaves and these leaves, along with their petioles, may also show distorted, curled growth. One way to diagnose a severe vascular infection is to pinch the stem. If the epidermis and outer layer of the cortex separate from the inner stem then there is severe vascular infection. These exposed parts will have a soapy feel. Canker lesions, though rare, may develop on the stem. These cankers are necrotic regions where the epidermis is gone. As the bacteria continues its colonization, the canker will deepen and expand. In terms of fruit development, tomatoes may fail to develop altogether or may look marbled because they are ripening unevenly.
If infection occurs at a late stage of plant development, plants are able to survive and generate fruits. However, the plant may appear stressed rather than wilted and may develop white interveinal areas that will develop into brown necrotic tissue. Often the seeds are infected as well.
Superficial infections increase the risk of epidemics. They occur when the bacteria multiply on the epidermis of the host, enter through stomata, or enter through a very shallow wound that does not allow the pathogen to reach the xylem tissue. The host may look like it was rubbed with cornmeal or coarse flour but it is actually a series of blisters that me be raised or sunken and appear white to pale orange. The most common leaf symptom is a dark brown spot surrounded by a sort of orange-like area on the edge of the leaf. Fruits may develop "bird's eye" spotting, which are pale green to white raised pustules that have a brown center and chlorotic halo. Pictures of these symptoms are available at the cited reference.
However, latent infections are common.
The Clavibacter michiganensis subsp. michiganensis wild type strain NCPPB382 carries two plasmids associated with virulence: pCM1 and pCM2. The avirulent strain, CMM100, does not contain these plasmids. Strains that carried one of the two plasmids were found to be virulent but wilting symptoms were delayed. The virulent and avirulent strains produced the same amount of exopolysaccharides, suggesting that EPS does not play a significant role in pathogenicity.
Disease cycle
The causal agent of bacterial wilt and canker of tomato survives in or on seeds for up to 8 months but occasionally also in plant refuse in the soil. The pathogen can be spread long distances because of its association with seeds. The risk of spreading the bacteria to healthy tomato plants is greatest during transplanting, tying, and suckering or any time when the host may be wounded. Once the bacteria enters the plant through a wound, it will move and multiply primarily in the xylem vessels. Once established, the bacteria may move into the phloem, pith, and cortex. Infection can result in either systemic or superficial disease. Systemic infections appear in 3–6 weeks and the risk of secondary infection goes up with water-splashing. The common occurrence of latent infections – presence of the pathogen within the host yet the host shows no symptoms – makes this pathogen especially dangerous.
However, the assumption that C. michiganensis does not overwinter in the soil is not without controversy. The genome of C. michiganesis has recently been sequenced and new theories will surely arise once more work has been completed. What is known is that Cmm can use hydrolysis products as carbon and energy sources by means of a number of ATP-binding cassette transporters and α- and β-glucosidases. This suggests that Cmm can survive in the soil as long as there is decaying host material present. It has also been determined that the genome of subsp. michiganensis does not have genes that encode for nitrate and nitrate reductases. This means that the bacteria depends on previously reduced nitrogen compounds or amino acids for its nitrogen source. Also lacking in the Cmm genome are genes for assimilatory sulfate reduction, which is associated with an auxotrophy for methionine – one of two amino acids that contain sulphur.
Cmm has a pathogenicity island (PI) that is encoded in the chromosome and is probably associated with colonization and plant defense evasion or suppression. This island has been subdivided into two subregions: chp and tomA. Serine proteases of the families S1A, Ppa, and PpA-E are encoded in the chp subregion as well as subtilase SbtA.
Environment
Warm temperature in the range of and the high relative humidity (>80%) are optimal environments for Clavibacter michiganesis subsp. michiganesis, a tomato bacterial canker symptom development. In humid or wet weather, slimy masses of bacteria ooze through the cracks to the surface of the stem, from which they are spread to leaves and fruits and cause secondary infections Infected host plants will show severe symptoms on hot days when there is a high transpiration rate since the bacteria may plug the xylem vessels.
Management
The best way to control a disease is use of healthy seeds that have already been acid extracted. In addition, using chemical treatments such as copper hydroxide or streptomycin in the seed bed, removing or isolating diseased crops can be helpful to reduce the rate of infection.
References
External links
Control de Cáncer Bacteriano (Clavibacter michiganensis) en el Cultivo de Tomate from Intagri S.C. In Spanish.
Clavibacter michiganensis subsp. michiganensis S 05, SO5 – Type strain – DSM 46364, ICPB CM 177, IMET 11518, LMG 7333, NCPPB 2979, PDDCC 2550 BacDiveID (id 7289)
Microbacteriaceae
Soil biology
Bacterial plant pathogens and diseases
Bacteria described in 1910 | Clavibacter michiganensis | Biology | 1,876 |
24,642,384 | https://en.wikipedia.org/wiki/Venus%20for%20Men | The Venus for Men, previously sold as the Venus 2000, is a self-actuated masturbation aid for men that applies sexual stimulation using a mechanism outwardly similar to a milking machine. The machine works with or without an erection. Metro has described it as a sex toy "for the serious onanist". In addition to masturbation, the machine may also be used for orgasm control practices such as edging or forced orgasm.
Creation
The Venus II was invented by Rick Gellert, with the assistance of Valentin Tsitrin, a Russian engineer. Gellert has written:
...It seems male desire for sexual activity ranges from needing an orgasm once in many weeks to wanting several in a day. [...] after hundreds of variations, I developed a product unique enough so that I was awarded patent #5501650.
The device was marketed as Venus II from October 1993 to April 1998. Gellert and Tsitrin presented their device to Abco Research Associates in 1993 (also manufacturer of the Sybian), and Abco helped them launch and market it. As a result, Abco became the primary marketer of the Venus II. In April 1997, Abco purchased the Venus II patent along with all manufacturing and marketing rights. This led to the launch of an improved version, Venus 2000.
In 2014, Abco modified the name of the product to Venus by Sybian. They also refer to the product as Venus For Men.
Mechanics
The design of the device was covered by U. S. patent 5501650. It consists of a main box linked to a cylindrical "receiver" that fits over the penis by a connecting hose. The "receiver" superficially resembles the teat cup of a milking machine, and contains an inner and outer chamber separated by a cylindrical flexible rubber liner. Only the outer chamber is linked to the main box, with the inner chamber open at one end, ready for the insertion of the penis. Unlike a milking machine, the other end of the Venus 2000's inner chamber is not connected to a suction hose, but instead covered by a cap that contains a one-way valve that leads to the open air.
The main box contains a gearmotor which drives a reciprocating diaphragm. Air moves to and from the outer chamber of the "receiver" via the hose. The device works by sucking in the shaft of the user's penis when the tip is placed against the receiver's opening before activation, using the partial vacuum created by the removal of air from the inner liner via the one-way valve at the closed end of the receiver. The amount of air in the system is adjustable and determines the stroke length. Most users can adjust it to move the full length of the shaft. A significant amount of personal lubricant is needed to be added within the liner for the machine to operate correctly.
The system is controlled during operation by two small control boxes. One of them is an electrical control box, with a speed adjustment knob, attached to the main box by an electrical cable. The other is a pneumatic control box, linked by a rubber tube to the diaphragm chamber, and has two push-buttons, one to add air to the system, and the other to remove air from the system. The final adjustment possible is an internal adjustment that can be used to change the amplitude of the pumping motion, but this is not available in operation, as adjusting it requires the main box of the machine to be dismantled and reassembled.
For best operation, all the components of the "receiver" need to be sized for the penile dimensions of the user. To this end, the plastic receiver bodies are available in a variety of tube lengths and diameters, and the rubber liner material also comes in a variety of diameters.
Specifications
Dimensions: 6" high, 8" wide and 9-1/2" long and weighs 11 pounds.
Gearmotor: The unit is powered by a 1/16 HP – 15:1 ratio gearmotor made by Bodine Electric Co.
Diaphragm: Air is moved by a specially designed and molded diaphragm. It has the ability to push and pull air at a high speed.
Personalized stroke-length adjustment: The Venus 2000 has an internal adjustment point with 5 possible settings that controls the amount of airflow. The unit setting is based on the size of receiver used.
See also
Sex machine
Breeding mount
References
External links
U.S. patent #5501650, "Automated masturbatory device"
As of October 20, 2009, this article uses content from Venusformen.com, which is licensed under the CC-By-SA and GFDL (see here). All relevant terms must be followed.
American inventions
Male sex toys
Machine sex
Ejaculation inducing devices | Venus for Men | Physics,Technology | 995 |
68,312,748 | https://en.wikipedia.org/wiki/Papposaurus | Papposaurus is an extinct genus of proterogyrinid embolomere which lived in the Mississippian (early Carboniferous) of Scotland. It is known from a single species, Papposaurus traquiairi, which is based on an isolated femur discovered in ironstone near Loanhead. Though originally compared closely to reptiles, subsequent study has revealed closer similarity to basal embolomeres such as Proterogyrinus and Archeria. With such limited remains, Papposaurus may not be a valid genus. The femur was redescribed in 1986 by T. R. Smithson, who considered Papposaurus traquairi a nomen vanum possibly synonymous with Proterogyrinus scheelei.
References
Embolomeres
Nomina dubia
Serpukhovian life
Mississippian sarcopterygians of Europe
Fossil taxa described in 1914 | Papposaurus | Biology | 185 |
10,969,498 | https://en.wikipedia.org/wiki/Quinaria | A quinaria (plural: quinariae) is a Roman unit of area, roughly equal to . Its primary use was to measure the cross-sectional area of pipes in Roman water distribution systems. A "one quinaria" pipe is in diameter.
In Roman times, there was considerable ambiguity regarding the origin of the name, and the actual value of a quinaria. According to Frontinus:
...Those who refer (the quinaria) to Vitruvius and the plumbers, declare that it was so named from the fact that a flat sheet of lead 5 digits wide, made up into a round pipe, forms this ajutage. But this is indefinite, because the plate, when made up into a round shape, will be extended on the exterior surface and contracted on the interior surface. The most probable explanation is that the quinaria received its name from having a diameter of 5/4 of a digit...
In other words, Vitruvius claimed that the name was derived from a pipe created from a flat sheet of lead "5 digits wide", roughly , but Frontinus contested the definitiveness of this because the exterior circumference of the resulting pipe would be larger than the interior circumference. According to Frontinus, the name and value is derived from a pipe having a diameter of "5/4 of a digit". Using Vitruvius' standard, the value of a quinaria is , and the resulting pipe would have a diameter of .
The importance of this measure was that water taxes in ancient Rome were based on the size of the supply pipe.
See also
Ancient Roman weights and measures
Water theft#Roman period
Notes and references
External links
The Quinaria, part of the Encyclopædia Romana
Units of area
Human-based units of measurement
Ancient Roman units of measurement | Quinaria | Mathematics | 383 |
5,685,631 | https://en.wikipedia.org/wiki/Stark%20conjectures | In number theory, the Stark conjectures, introduced by and later expanded by , give conjectural information about the coefficient of the leading term in the Taylor expansion of an Artin L-function associated with a Galois extension K/k of algebraic number fields. The conjectures generalize the analytic class number formula expressing the leading coefficient of the Taylor series for the Dedekind zeta function of a number field as the product of a regulator related to S-units of the field and a rational number.
When K/k is an abelian extension and the order of vanishing of the L-function at s = 0 is one, Stark gave a refinement of his conjecture, predicting the existence of certain S-units, called Stark units, which generate abelian extensions of number fields.
Formulation
General case
The Stark conjectures, in the most general form, predict that the leading coefficient of an Artin L-function is the product of a type of regulator, the Stark regulator, with an algebraic number.
Abelian rank-one case
When the extension is abelian and the order of vanishing of an L-function at s = 0 is one, Stark's refined conjecture predicts the existence of Stark units, whose roots generate Kummer extensions of K that are abelian over the base field k (and not just abelian over K, as Kummer theory implies). As such, this refinement of his conjecture has theoretical implications for solving Hilbert's twelfth problem.
Computation
Stark units in the abelian rank-one case have been computed in specific examples, allowing verification of the veracity of his refined conjecture. These also provide an important computational tool for generating abelian extensions of number fields, forming the basis for some standard algorithms for computing abelian extensions of number fields.
The first rank-zero cases are used in recent versions of the PARI/GP computer algebra system to compute Hilbert class fields of totally real number fields, and the conjectures provide one solution to Hilbert's twelfth problem, which challenged mathematicians to show how class fields may be constructed over any number field by the methods of complex analysis.
Progress
Stark's principal conjecture has been proven in a few special cases, such as when the character defining the L-function takes on only rational values. Except when the base field is the field of rational numbers or an imaginary quadratic field, which were covered in the work of Stark, the abelian Stark conjectures is still unproved for number fields. More progress has been made in function fields of an algebraic variety.
related Stark's conjectures to the noncommutative geometry of Alain Connes. This provides a conceptual framework for studying the conjectures, although at the moment it is unclear whether Manin's techniques will yield the actual proof.
Variations
In 1980, Benedict Gross formulated the Gross–Stark conjecture, a p-adic analogue of the Stark conjectures relating derivatives of Deligne–Ribet p-adic L-functions (for totally even characters of totally real number fields) to p-units. This was proved conditionally by Henri Darmon, Samit Dasgupta, and Robert Pollack in 2011. The proof was completed and made unconditional by Dasgupta, Mahesh Kakde, and Kevin Ventullo in 2018. A further refinement of the p-adic conjecture was proposed by Gross in 1988.
In 1984, John Tate formulated the Brumer–Stark conjecture, which gives a refinement of the abelian rank-one Stark conjecture at totally split finite primes (for totally complex extensions of totally real base fields). The function field analogue of the Brumer–Stark conjecture was proved by John Tate and Pierre Deligne in 1984. In 2023, Dasgupta and Kakde proved the Brumer–Stark conjecture away from the prime 2.
In 1996, Karl Rubin proposed an integral refinement of the Stark conjecture in the abelian case. In 1999, Cristian Dumitru Popescu proposed a function field analogue of Rubin's conjecture and proved it in some cases.
Notes
References
External links
Conjectures
Unsolved problems in number theory
Field (mathematics)
Algebraic number theory
Zeta and L-functions | Stark conjectures | Mathematics | 861 |
705,285 | https://en.wikipedia.org/wiki/Boardwalk%20Hotel%20and%20Casino | The Boardwalk Hotel and Casino was a Coney Island-style hotel on the Las Vegas Strip. The property began in 1966, as a Holiday Inn. Norbert Jansen added a gift shop to the hotel in 1972, and later opened the Slot Joynt casino. In 1985, Jansen renamed the Holiday Inn as the Viscount Hotel, part of a U.S. chain. Four years later, he merged Slot Joynt with the Viscount and renamed them as the Boardwalk. It rejoined the Holiday Inn chain in 1994, through a franchise deal which eventually ended in 2002.
A carnival facade was added in 1995, featuring non-functional ride replicas. A 15-story tower was finished in 1996, giving the Boardwalk a total of 653 rooms. The casino was also enlarged, bringing it to . The resort occupied . It was popular for its cheap food and rooms, and its small size compared to nearby megaresorts.
In 1998, the Boardwalk was sold to Mirage Resorts, which later became MGM Mirage. The resort closed on January 9, 2006, to help make way for MGM's CityCenter project. The hotel's main tower was imploded on May 9, 2006. The former Boardwalk site is now occupied by CityCenter's Waldorf Astoria hotel.
History
The Boardwalk began as a 138-room Holiday Inn hotel with a restaurant, cocktail lounge, and meeting space with a capacity for 100 people. Located at 3740 South Las Vegas Boulevard, the hotel was designed by architect Homer Rissman, and was completed in 1966. It opened with a six-floor tower.
In March 1966, employees of the Holiday Inn, who were represented by the Culinary Workers Union, began picketing in front of the hotel, alleging that they did not receive wages and conditions that were standard for the area. Holiday Inn denied the claim, stating that wages and conditions were equal to or above local standards. The union ultimately lost its fight.
A second hotel tower opened in 1968, and the hotel later became known as Holiday Inn South and Holiday Inn South Strip, differentiating it from other Las Vegas locations such as the Holiday Inn Center Strip.
In October 1975, the hotel's innkeeper died in a fire that was believed to have been started by a cigarette. The fire was confined to the innkeeper's room on the fifth floor, and caused approximately $40,000 in damage. Guests of the fifth floor were evacuated, and approximately 10 were treated for smoke inhalation.
Norbert Jansen, former owner of Pioneer Club, had opened a gift shop, Holiday Gifts, at the hotel in 1972. It was later renamed Holiday Gifts South. Avis Jansen, Norbert's wife, eventually sought to install 15 slot machines at the gift shop. However, the Nevada Gaming Control Board voted against this proposal in December 1977. She had been rejected due to the fact that her husband was the landlord of the business; he had previously been convicted of tax evasion in the 1960s, and was also involved in a company that filed bankruptcy. By 1981, the Jansens had opened a casino known as Slot Joynt, which later became part of the hotel.
In 1985, with little fanfare, the Jansens renamed the Holiday Inn as the Viscount Hotel, part of a chain with 14 other locations in the U.S. At that time, the six-story hotel included 204 rooms.
In 1989, Jansen proposed the addition of a 21-story working slot machine, the world's largest, to be built in front of Slot Joynt. However, this idea was rejected by the Clark County Commission. Despite receiving approval later that year, Jansen decided against the idea due to its rising cost, going from $5 million to $7 million.
Boardwalk (1989–2006)
In February 1989, Jansen converted the Viscount and Slot Joynt into the Boardwalk Hotel and Casino. Boardwalk Casino Inc. became a public company in February 1994, following an initial public offering. Two months later, plans were announced for a $9 million renovation and expansion that would include the enlargement of the casino, which measured .
The hotel rejoined the Holiday Inn chain through a new franchise deal later in 1994, and a Coney Island theme was added shortly thereafter. A carnival facade was built in 1995, adding non-functional replicas of a parachute drop, roller coaster, and Ferris wheel, as well as a giant clown face and retail shops. The casino was also expanded, and a 15-floor, 451-room tower was finished in 1996. That year, Jacobs Entertainment, Inc. made a $9 million investment in the Boardwalk. In 1997, the resort added the 370-seat Surf Buffet, which ran a television commercial starring professional boxer Butterbean.
Jansen, speaking about his earlier proposal for a giant slot machine, said in 1995: "It's not officially dead. But I'd say that it's dying, that I probably won't see it in my lifetime". Jansen died of cancer in January 1997, at the age of 78. Avis Jansen continued to operate the gift shop until the Boardwalk's closure.
The Boardwalk occupied . In December 1997, Mirage Resorts agreed to purchase the resort and three adjacent parcels for $135 million. The $105 million Boardwalk sale was approved by the Nevada Gaming Commission in June 1998. At the time, the Boardwalk included 650 employees, 653 rooms and a casino. Minor improvements were planned for the Boardwalk, with no immediate plans to replace it.
A decision to expand or replace the Boardwalk was expected within three or four years. However, Mirage Resorts was acquired by MGM Grand, Inc. in 2000, forming MGM Mirage. The newly formed company delayed its plans for a redevelopment of the Boardwalk site, choosing instead to focus on its new Borgata resort, opened in Atlantic City in 2003. MGM took its time on a Boardwalk replacement, which was contingent on the success of Borgata. The Holiday Inn name was dropped in 2002.
In November 2004, MGM announced plans for CityCenter, a mixed-use project that would be built on , including the Boardwalk site. The Boardwalk closed on January 9, 2006. It had been popular for its cheap food and rooms, as well as its small size compared to nearby megaresorts. Columnist John L. Smith of the Las Vegas Review-Journal called the Boardwalk " a testament to the local belief that even a terribly tacky joint -- one with an Atlantic City theme, for crying out loud -- can grind out a cash flow if it happens to be located in the heart of the action on the Strip".
The Boardwalk's main hotel tower was imploded by Controlled Demolition, Inc. on May 9, 2006. Much of the debris from the imploded structure was recycled as building material for CityCenter, including its foundation. Glass and bathroom fixtures were shipped to other countries for re-use. Former lieutenant governor Lonnie Hammargren, a collector of Las Vegas memorabilia, purchased the Boardwalk's Ferris wheel, a Surf Buffet sign, the resort's wedding gazebo, and a 15-foot-high lighthouse. The facade's clown head was demolished. The Boardwalk site is now occupied by CityCenter's Waldorf Astoria hotel.
Notable entertainers
The Unknown Comic performed at the Boardwalk in the mid-1990s. Elvis impersonator Trent Carlini entertained in the casino's 100-seat Lighthouse Showroom from 1996 to 2001, sharing the venue at one point with magician Dixie Dooley. Purple Reign, a Prince tribute show, ran in the same venue from 2001 to 2006.
Notes
References
External links
Video recording of the Boardwalk implosion
Casinos completed in 1966
Hotel buildings completed in 1966
Hotel buildings completed in 1996
Hotels established in 1966
Hotels disestablished in 2006
Defunct casinos in the Las Vegas Valley
Defunct hotels in the Las Vegas Valley
2006 disestablishments in Nevada
Buildings and structures demolished in 2006
Buildings and structures demolished by controlled implosion
Skyscraper hotels in Paradise, Nevada
Demolished hotels in Clark County, Nevada
Casino hotels
1966 establishments in Nevada | Boardwalk Hotel and Casino | Engineering | 1,645 |
191,827 | https://en.wikipedia.org/wiki/Bioregionalism | Bioregionalism is a philosophy that suggests that political, cultural, and economic systems are more sustainable and just if they are organized around naturally defined areas called bioregions (similar to ecoregions). Bioregions are defined through physical and environmental features, including watershed boundaries and soil and terrain characteristics. Bioregionalism stresses that the determination of a bioregion is also a cultural phenomenon, and emphasizes local populations, knowledge, and solutions.
Bioregionalism is a concept that goes beyond national boundaries—an example is the concept of Cascadia, a region that is sometimes considered to consist of most of Oregon and Washington, the Alaska Panhandle, the far north of California and the West Coast of Canada, sometimes also including some or all of Idaho and western Montana. Another example of a bioregion, which does not cross national boundaries, but does overlap state lines, is the Ozarks, a bioregion also referred to as the Ozarks Plateau, which consists of southern Missouri, northwest Arkansas, the northeast corner of Oklahoma, southeast corner of Kansas.
Bioregions are not synonymous with ecoregions as defined by organizations such as the World Wildlife Fund or the Commission for Environmental Cooperation; the latter are scientifically based and focused on wildlife and vegetation. Bioregions, by contrast, are human regions, informed by nature but with a social and political element. In this way bioregionalism is simply political localism with an ecological foundation.
Overview
The term was coined by Allen Van Newkirk, founder of the Institute for Bioregional Research, in 1975, given currency by Peter Berg and Raymond F. Dasmann in the early 1970s, and has been advocated by writers such as David Haenke and Kirkpatrick Sale.
The bioregionalist perspective opposes a homogeneous economy and consumer culture with its lack of stewardship towards the environment. This perspective seeks to:
Ensure that political boundaries match ecological boundaries.
Highlight the unique ecology of the bioregion.
Encourage consumption of local foods where possible.
Encourage the use of local materials where possible.
Encourage the cultivation of native plants of the region.
Encourage sustainability in harmony with the bioregion.
Bioregions
Bioregions are a foundational concept within the philosophical system called Bioregionalism. A bioregion is defined along watershed and hydrological boundaries, and uses a combination of bioregional layers, beginning with the oldest "hard" lines; geology, topography, tectonics, wind, fracture zones and continental divides, working its way through the "soft" lines: living systems such as soil, ecosystems, climate, marine life, and the flora and fauna, and lastly the "human" lines: human geography, energy, transportation, agriculture, food, music, language, history, indigenous cultures, and ways of living within the context set into a place, and it's limits to determine the final edges and boundaries.
Peter Berg and Judy Goldhaft who founded the Planet Drum foundation in 1973 and helped to popularize the concept of bioregions and bioregionalism, located in San Francisco and which just celebrated its 50th anniversary in 2023 defines a bioregion as the following::
Bioregional mapping
This idea of bioregionalism is also rooted in an important concept called bioregional mapping, a powerful tool to increase understanding, change the story and influence policy. Bioregional Mapping is a participatory approach to cartography that focuses on mapping the natural, ecological and human realities of that have emerged in a place within a bioregion—an area defined by its natural boundaries, such as watersheds, ecosystems, and cultures that arise form a place, rather than human borders. This method highlights the interconnectedness of the region's natural systems and human communities, offering a holistic view of the landscape that integrates ecological data with cultural and historical insights.
A good bioregional map shows layers of geology, flora, fauna, and inhabitation over time. This approach empowers individuals to contribute to the documentation of local knowledge, history, and cultural significance, thereby creating maps that are more inclusive and representative of the lived experiences within the bioregion. Community mapping includes the identification of traditional pathways, local species, historical landmarks, stories, songs, how things change over time, and other culturally significant sites that might not appear on standard maps.
Bioregional mapping also aligns with Indigenous mapping practices by recognizing the importance of natural boundaries and the relationship between people and their environment. The idea of bioregional mapping largely grew from the Tsleil-Waututh First Nation, Nisga'a, Tsilhqotʼin, Wetʼsuwetʼen first nations who used Bioregional Mapping to create some of the first bioregional atlases as part of court cases to defend their sovereignty in the 1980s and 1990s, one such example being the Tsilhqotʼin Nation v British Columbia.
One of the best examples of a richly communicative bioregional map is David McClosky's new map of Cascadia.
Relationship to environmentalism
Bioregionalism, while akin to modern environmentalism in certain aspects, such as a desire to live in harmony with nature, differs in certain ways from the 20th century movement.
According to Peter Berg, bioregionalism is proactive, and is based on forming a harmony between human culture and the natural environment, rather than being protest-based like the original environmental movement. Also, modern environmentalists saw human industry in and of itself an enemy of environmental stability, viewing nature as a victim needing to be saved; bioregionalists see humanity and its culture as a part of nature, focusing on building a positive, sustainable relationship with both the sociological and ecological environments, rather than a focus on completely preserving and segregating the wilderness from the world of humanity.
In this way the sentiments of Bioregionalism echo those of Classical Environmentalism, and early environmentalists such as Henry David Thoreau are sometimes viewed as predecessors of the Bioregionalist movement.
History
Bioregionalism emerged in the 1970s, developing primarily along the western coast of North America, and specifically from a broad coalition of poets, artists, writers, community leaders, and back-to-the-landers, and from the Digger movement which had grown in the late 1960s Beat Scene in San Francisco, and as a counter to the mainstream environmental movement, which many felt was reactionary and negative. They envisioned a positive, place-based alternative to mainstream efforts within a capitalist framework, or those of nation-states or other international bodies. This included many different individuals, including "Peter Berg, Judy Goldhaft, Raymond Dasmann, Kirkpatrick Sale, Judith Plant, Eleanor Wright, Doug Aberley, Stephanie Mills, Jim Dodge, Freeman House, Van Andruss, David Haenke, and Gary Snyder", working together through the Planet Drum foundation, and similar groups to create a new place-based philosophy they called bioregionalism.
Bioregionalism also directly grew from a relationship with the civil rights and American Indian Movement, and efforts to reclaim their languages, territories and maps, and what bioregionalists saw as the global collapse of traditional ecological knowledge, language suppression and revitalization, and a hope that maps reframing names from "North America" to "Turtle Island" would help bioregions become frameworks for decolonization, as well as more accurate cultural representation and recognition of Indigenous sovereignty. It also grew from civil rights movement, anti-war movement, anti-nuclear movement, the Diggers, as well as an increasing awareness of pervasive ecological pollution, especially in areas like Los Angeles.
Allen Van Newkirk and the Institute for Bioregional Research
The term bioregion as it relates to bioregionalism is credited to Allen Van Newkirk, a Canadian poet and biogeographer. In this field, the idea of "bioregion" probably goes back much earlier than published material suggests, being floated in early published small press zines by Newkirk, and in conversational dialogue. He would go on to found the Institute for Bioregional Research and issued a series of short papers using the term bioregion as early as 1970, which would start to circulate the idea of "bioregion". Newkirk met Peter Berg (another early scholar on Bioregionalism) in San Francisco in 1969 and again in Nova Scotia in 1971 where he shared the idea with Berg. Peter Berg, who would go on to found the Planet Drum foundation, and become a leading proponent of "bioregions" learned of the term in 1971 while Judy Goldhaft and Peter Berg were staying with Allen Van Newkirk, before Berg attended the first United Nations Conference on the Human Environment in Stockholm during June 1972. Berg would go on to found the Planet Drum Foundation in 1973, and they published their first Bioregional Bundle in that year, that also included a definition of a bioregion. Helping refine this definition, Author Kirkpatrick Sale wrote in 1974 that "A bioregion is a part of the earth's surface whose rough boundaries are determined by natural rather than human dictates, distinguishable from other areas by attributes of flora, fauna, water, climate, soils and landforms, and human settlements and cultures those attributes give rise to. in 1975 A. Van Newkirk published the first article calling for bioregionalism in a paper entitled "Bioregions: Towards Bioregional Strategy for Human Cultures" in which he advocates for the incorporation of human activity ("occupying populations of the culture-bearing animal") within bioregional definitions.
Judy Goldhaft, Peter Berg and the Planet Drum Foundation
Starting in 1973, Planet Drum Foundation in San Franscisco became a leading institution promoting bioregionalism. They published a series of publications looking at place, poetry, cultural expression, politics, art and many other subjects. From this group, other early bioregional groups started, such as the Frisco Bay Mussel Group, Raise the Stakes newsletters, and Bioregional Bundles that would carry the bioregional movement forward for the next several decades.
This started by creating bioregional “Bundles” that they would publish each year, that would be distinct to a bioregion, and help the people within that place define that bioregion. Each envelope would contain many different pieces of poetry, art, writing, science documents, and place-specific technology booklets, articles, maps, posters, photographs, directories, and calendars. From 1973 to 1985 Planet Drum published nine Bundles, on topics ranging as far as North America, South America, the Arctic Circle, West Africa, Morocco, the Pacific Rim, Japan, and China. From 1979-2000, Planet Drum began publishing Raise The Stakes, the Planet Drum Review, a bi-annual international publication which became an important central voice for the bioregional movement, bioregional organizers around North America and world, and for defining the term bioregion among those using it. By 1990, Planet Drum served as node for more than 250 bioregionally oriented groups in North America, including Canada and Mexico, with emerging movements in Australia, Latin America, Italy and Spain.
Raymond Dasmann and Reinhabiting California
One of the other early proponents of bioregionalism, and who helped define what a bioregion is, was American biologist and environmental scientist Raymond F. Dasmann. Dasmann studied at UC Berkeley under the legendary wildlife biologist Aldo Leopold, and earned his Ph.D. in zoology in 1954. Working with Peter Berg, and also contemporary with Allen Van Newkirk, Dasmann was one of the pioneers in developing the definition for the term "Bioregion", as well as conservation concepts of "Eco-development" and "biological diversity," and identified the crucial importance of recognizing indigenous peoples and their cultures in efforts to conserve natural landscapes. He began his academic career at Humboldt State University, where he was a professor of natural resources from 1954 until 1965. During the 1960s, he worked at the Conservation Foundation in Washington, D.C., as Director of International Programs and was also a consultant on the development of the 1972 Stockholm Conference on the Human Environment. In the 1970s he worked with UNESCO where he initiated the Man and the Biosphere Programme(MAB), an international research and conservation program. During the same period he was Senior Ecologist for the International Union for Conservation of Nature in Switzerland, initiating global conservation programs which earned him the highest honors awarded by The Wildlife Society, and the Smithsonian Institution.
This idea was carried forward and developed by ecologist Raymond Dasmann and Peter Berg in article they co-authored called Reinhabiting California in 1977, which argued that bioregions were more than just biotic provinces and biogeography, and that humans are a critical part of the idea of bioregions. Peter Berg and ecologist Raymond Dasmann said in their 1977 article "Reinhabiting California":"Reinhabitation involves developing a bioregional identity, something most North Americans have lost or have never possessed. We define bioregion in a sense different from the biotic provinces of Raymond Dasmann (1973) or the biogeographical province of Miklos Udvardy. The term refers both to geographical terrain and a terrain of consciousness—to a place and the ideas that have developed about how to live in that place. Within a bioregion, the conditions that influence life are similar, and these, in turn, have influenced human occupancy."This article defined bioregions as distinct from biogeographical and biotic provinces that ecologists and geographers had been developing by adding a human and cultural lens to the strictly ecological idea.
Murray Bookchin and the Institute for Social Ecology
This new movement grew strongly also on earlier work from Murray Bookchin, who ran the Institute for Social Ecology, and was deeply involved in influencing and helping define the early bioregional movement. Drawing on earlier traditions beginning with Ecology and Revolutionary Thought in 1964 Bookchin argued for the reorganization of American society based upon a decentralized regional model which would each encompass a single bioregion or ecosystem. His organization, the Institute for Social Ecology worked with the Planet Drum Foundation for the increased implementation of alternative forms of energy, reduction and restriction of carbon dioxide emissions, anti-globalism, and the implementation of a bioregional approach to economic development. For Bookchin, a bioregional approach to economic development accepted one of the basic assertions of Social Ecology that a human community is fundamentally a part of a total ecosystem. Furthermore, Bookchin felt that humans were a part of an earth society:
Peter Berg, writing about his experience helping to write the "Bioregions" issue of Coevolution Quarterly in the late 70's worked with Bookchin' to use his Ecology of Freedom, which Berg claimed to be an "invaluable help to set the autonomous and self-governing tone of bioregional discourse."
Bioregional Congresses
A major evolution in how bioregions were defined also occurred alongside this work in the mid-1980s, and can be attributed to David Haenke (b. 1945), Inspired by the call of Peter Berg, who released "Amble towards a Continental Congress" in 1976 for the bicentennial of the United States founding, Haenke conceptualized the Ozark Area Community Congress in 1977, started the Bioregional Project in 1982, launched the Ozarks Bioregional Congress in 1980, and then launched the first ever North American Bioregional Congress (NABC) in 1984.
David Haenke would also go on to be one of the founders of the United States Green Party, which he viewed as a political wing of the bioregional movement.
David Haenke had two questions he asked while defining a bioregion:
From 1984 through the 2010s, many regional groups, such as the Great Lakes, Kansas, Cascadia, would hold regional "Bioregional Congresses" for specific bioregions, and then every two years would gather as part of a North American bioregional congress. Cascadia for example held its first Cascadia Bioregional Congress at The Evergreen State College in 1986, an Ish River confluence in 1987, another Bioregional Congress in 1988 at Breitenbush in Oregon, and a third congress in Lillooet in British Columbia in 1989. This was also timed for the third North American Bioregional Congress which took place in Samish in 1988.
Bioregional Learning Centers
The idea of bioregions, and their uses was again expanded by Donella Meadows, author of The Limits to Growth in 1972, and was the primary premise for her to launch the Balaton Group in 1982. A big part of this for her, was using bioregions as the basis for "bioregional learning centers", each of which would be responsible for a discrete bioregion. In her words, the purpose of a bioregion was to:
In politics
North American Bioregional Assemblies have been meeting at bi-annual gatherings of bioregionalists throughout North America since 1984 and have given rise to national level Green Parties. The tenets of bioregionalism are often used by green movements, which oppose political organizations whose boundaries conform to existing electoral districts. This problem is perceived to result in elected representatives voting in accordance with their constituents, some of whom may live outside a defined bioregion, and may run counter to the well-being of the bioregion.
At the local level, several bioregions have congresses that meet regularly. For instance, the Ozark Plateau bioregion hosts a yearly Ozark Area Community Congress, better known as OACC, which has been meeting every year since 1980, most often on the first weekend in October. The Kansas Area Watershed, "KAW" was founded in 1982 and has been meeting regularly since that time. KAW holds a yearly meeting, usually in the spring.
The government of the Canadian province of Alberta created the "land-use framework regions" in 2007 roughly corresponding to each major river basin within the province. This is supported by local initiatives such as the Beaver Hills Initiative to preserve an ecoregion which encompasses Elk Island National Park and the surrounding area.
See also
References
Further reading
Alexander, D. (1990). "Bioregionalism: Science or sensibility?" Environmental Ethics, 12(2), 161-173. DOI:10.5840/enviroethics199012217. Retrieved from: http://hdl.handle.net/10613/2725
Mike Carr, Bioregionalism and Civil Society: Democratic Challenges to Corporate Globalism, UBC Press, 2004. .
Peter Berg, editor. Reinhabiting A Separate Country: A Bioregional Anthology of Northern California. San Francisco: Planet Drum, 1978. .
Peter Berg, Envisioning Sustainability, Subculture Books, 2009. .
Michael McGinnis, editor. Bioregionalism, Routledge, 1998. .
Ryan Moothart. Towards Cascadia. Minneapolis, MN: Mill City Press. .
Kirkpatrick Sale, Dwellers in the Land: The Bioregional Vision. Random House, 1985. (University of Georgia Press, 2000).
Gary Snyder. A Place in Space: Ethics, Aesthetics, and Watersheds. Counterpoint, 1995.
Robert Thayer. LifePlace: Bioregional Thought and Practice, University of California Press, 2003.
Emanuele Guerrieri Ciaceri. Bioregionalismo. La visione locale di un mondo globale. Argo Edizioni, Italia 2006.
Doug Aberley, editor. Boundaries of Home: Mapping for Local Empowerment. New Society Publishers, 1998.
External links
Free Cascadia.org, the website belonging to Alexander Baretich, designer of the Cascadian flag, and advocate of Bioregionalism.
Encyclopedia of Earth: Ecoregion
North American Bioregional Congress
Ozark Area Community Congress
Planet Drum Foundation website.
Putah-Cache Bioregion Project - interdisciplinary research and educational project at UC Davis
Bioregionalism at Columbia Encyclopedia, 2020
Deep ecology
Ecology terminology
Sustainable design
Anarchist theory
Ecoregions
Cultural politics
Environmental movements | Bioregionalism | Biology,Environmental_science | 4,128 |
15,909,871 | https://en.wikipedia.org/wiki/Symbolic%20trajectory%20evaluation | Symbolic trajectory evaluation (STE) is a lattice-based model checking technology that uses a form of symbolic simulation. STE is essentially used for computer hardware, that is circuit verification. The technique uses abstraction, meaning that details of the circuit behaviour are removed from the circuit model. It was first developed by Carl Seger and Randy Bryant in 1995 as an alternative to "classical" symbolic model checking.
References
C.-J. H. Seger, and R. E. Bryant, Formal Verification by Symbolic Evaluation of Ordered Trajectories, Formal Methods in System Design, Vol. 6, No. 2 (March, 1995), pp. 147–190
Model checking
Management cybernetics | Symbolic trajectory evaluation | Technology | 140 |
900,383 | https://en.wikipedia.org/wiki/Victor%20Grignard | Francois Auguste Victor Grignard (6 May 1871 – 13 December 1935) was a French chemist who won the Nobel Prize for his discovery of the eponymously named Grignard reagent and Grignard reaction, both of which are important in the formation of carbon–carbon bonds. He also wrote some of his experiments in his laboratory notebooks.
Biography
Grignard was the son of a sailmaker. He was a hard-working student and was described as having a humble and friendly attitude. He also had a talent for mathematics. After attempting to major in mathematics, Grignard failed his entrance exams before being drafted into the army in 1892. After one year of service, he returned to pursue his studies of mathematics at the University of Lyon and finally obtained his degree Licencié ès Sciences Mathématiques in 1894. In December of the same year, he transferred to chemistry and began working with Professors Philippe Barbier (1848–1922) and Louis Bouveault (1864–1909). After working with stereochemistry and énines, Grignard was not impressed with the subject matter and asked Barbier about a new direction for his doctoral research. Barbier advised that Grignard study how a failed Saytzeff reaction using zinc, was successful, in low yields, after substitution of magnesium. They sought to synthesize alcohols from alkyl halides, aldehydes, ketones, and alkenes. Grignard hypothesized that the aldehyde or ketone prevented the magnesium from reacting with the alkyl halide, accounting for the low yields. He tested his hypothesis by first adding an alkyl halide and magnesium filings to a solution of anhydrous ether and then adding the aldehyde or ketone. This resulted in a drastic increase in the yield of the reaction.
A couple of years later, Grignard was able to isolate the intermediate. He had heated a mixture of magnesium turnings and isobutyl iodide and added dry ethyl ether to the mixture, observing the reaction. The product is known as a Grignard reagent. Named after him, this organo-magnesium compound (R-MgX) (R = alkyl ; X = Halogen) readily reacts with ketones, aldehydes, and alkenes to produce their respective alcohols in impressive yields. Grignard had discovered the synthetic reaction that now bears his name (the Grignard reaction) in 1900. In 1901, he published his doctoral thesis titled "Thèses sur les combinaisons organomagnesiennes mixtes et leur application à des synthèses d‘acides, d‘alcools et d‘hydrocarbures". He became a lecturer in organic chemistry at the University of Nancy in 1909, and was promoted to full professor in 1910. In 1912 he and Paul Sabatier (1854–1941) were awarded the Nobel Prize in Chemistry. During World War I he studied chemical warfare agents with Georges Urbain at Sorbonne University, particularly the manufacture of phosgene and the detection of mustard gas. In 1918, Grignard discovered that sodium iodide could be used as a battlefield test for mustard gas. Sodium iodide converts mustard gas to diiododiethyl sulfide, which crystallizes more easily than mustard gas. This test could detect as little as 0.01 gram of mustard gas in one cubic meter of air and was successfully used on the battlefield. His counterpart on the German side was another Nobel Prize–winning chemist, Fritz Haber.
Grignard died on 13 December 1935 in Lyon, at the age of 64. By that time, around 6,000 papers reporting applications of the Grignard reaction had been published.
Grignard reaction
Grignard is most noted for devising a new method for generating carbon-carbon bonds using magnesium to couple ketones and alkyl halides. This reaction is valuable in organic synthesis. It occurs in two steps:
Formation of the "Grignard reagent", which is an organomagnesium compound made by the reaction of an organohalide, R-X (R = alkyl or aryl; and X is a halide, usually bromide or iodide) with magnesium metal. The Grignard reagent is usually described with the general chemical formula R-Mg-X, although its structure is more complex.
Addition of the carbonyl, in which a ketone or an aldehyde is added to the solution containing the Grignard reagent. The carbon atom that is bonded to Mg transfers to the carbonyl carbon atom, and the oxygen of the carbonyl carbon becomes attached to the magnesium to give an alkoxide. The process is an example of a nucleophilic addition to a carbonyl. After the addition, the reaction mixture is treated with aqueous acid to give an alcohol, and the magnesium salts are subsequently discarded.
Military service
Grignard was drafted into the French military as part of obligatory military service in 1892. Within the two years of his first session of service he rose to the rank of corporal. He was demobilized in 1894 and returned to Lyon to pursue his education. He was awarded a medal of the Legion of Honour and made a Chevalier in 1912 after winning the Nobel Prize. When World War I broke out, Grignard was drafted back into the military, keeping his rank of corporal. He was placed on sentry duty, and served there for several months until he was brought to the attention of the General Staff. Grignard had been wearing his Medal of the Legion of Honour, despite being ordered to take it off by a superior. After looking more into Grignard, the General Staff decided that he would be better suited for research than sentry duty, so they assigned him to the explosives division. Grignard's research shifted to antidotes to chemical weapons when production of TNT was no longer sustainable, and eventually Grignard was assigned to research new chemical weapons for the French army.
Honors
1912: Nobel Prize in Chemistry for his discovery of the Grignard reagent (shared the award with fellow Frenchman Paul Sabatier).
1912: Lavoisier Medal, Société Chimique de France
1933: Légion d'Honneur, Commander
Notes
References
External links
including the Nobel Lecture, 11 December 1912 The Use of Organomagnesium Compunds in Preparative Organic Chemistry
Comptes Rendus
1871 births
1935 deaths
19th-century French chemists
French organic chemists
Nobel laureates in Chemistry
Members of the French Academy of Sciences
French Nobel laureates
Chemical warfare
People from Manche
Academic staff of Nancy-Université
Commanders of the Legion of Honour
20th-century French chemists | Victor Grignard | Chemistry | 1,398 |
499,393 | https://en.wikipedia.org/wiki/Federal%20Department%20of%20Environment%2C%20Transport%2C%20Energy%20and%20Communications | The Federal Department of Environment, Transport, Energy and Communications (DETEC, , , , ) is one of the seven departments of the Swiss federal government, headed by a member of the Swiss Federal Council.
Organisation
The department is composed of the following offices:
General Secretariat
Federal Office for Spatial Development (ARE): Coordinates area planning between the federal agencies, the cantons and the municipalities.
Federal Office for the Environment (FOEN): Responsible for matters of the environment, including the protection of plants and animals and the protection against noise, air pollution or natural hazards.
Federal Office for Civil Aviation (FOCA): Regulates civil aviation.
Federal Office of Communications (OFCOM): Regulates radio and TV stations, notably the Swiss Broadcasting Corporation.
Federal Office of Energy (FOE): Responsible for the provision of electrical energy at the federal level, as well as for the supervision of dams.
Federal Office of Transport (FOT): Responsible for public transport at the federal level, including the development of the federal rail network and navigation on the Rhine.
Federal Roads Office (FEDRO): Responsible for the construction, maintenance and operation of the national highway network.
The following independent authorities are affiliated to the DETEC for administrative purposes:
Swiss Transportation Safety Investigation Board (STSB, formerly Aircraft Accident Investigation Bureau and Investigation Bureau for Railway, Funicular and Boat Accidents).
Federal Communications Commission (ComCom): Regulates the telecommunications market, awards service licences, rules on interconnection disputes and approves frequency and numbering plans.
Federal Electricity Commission (ElCom): monitors electricity prices, rules as a judicial authority on disputes relating to network access and payment of cost-covering feed-in of electricity produced from renewable energy, monitors electricity supply security and regulates issues relating to international electricity transmission and trading.
Federal Postal Services Commission (PostCom): Regulates the Swiss Post and Swiss postal market.
Rail Transport Commission (RailCom): Arbitrates in disputes over access to the rail network and the calculation of fees for the use of infrastructure.
Independent Complaints Authority for Radio and Television (ICA): Decides on complaints related to radio and television programmes.
Safety Office (formerly known as the Civil Aviation Safety Office, CASO): supports the development of safety in land, sea and air transport, in the use, transport and distribution of energy, and for communications infrastructures
Reporting Office for Just Culture in Civil Aviation (ROJCA): strengthens Just Culture through the protection of the information source of an occurrence reporting in Swiss Civil Aviation.
Federal Inspectorate for Heavy Current Installations (ESTI): Responsible for inspecting low and heavy-current electrical installations.
Swiss Federal Nuclear Safety Inspectorate (ENSI): Assesses and monitors security and radiation protection in Swiss nuclear installations.
Federal Pipelines Inspectorate (ERI): Responsible for the planning, construction and operation of fuel pipeline systems in Switzerland and Liechtenstein.
Name of department
1848–1859: Department of Posts and Construction
1860–1872: Department of Posts
1873–1878: Department of Posts and Telegraph
1879–1962: Department of Posts and Railways
1963–1978: Department of Transport, Communications and Energy
1979–1997: Federal Department of Transport, Communications and Energy
Since 1998: Federal Department of Environment, Transport, Energy and Communications
List of heads of the department
See also
Energy in Switzerland
Notes and references
External links
Official website
Environment, Transport, Energy and Communications
Communications in Switzerland
Transport in Switzerland
Energy in Switzerland | Federal Department of Environment, Transport, Energy and Communications | Engineering | 690 |
63,031,017 | https://en.wikipedia.org/wiki/HD%20101584 | HD 101584 is a suspected post-common envelope binary about 1,800 to 5,900 light-years distant in the constellation of Centaurus. The system is bright at optical wavelengths with an apparent visual magnitude of about 7. The primary is either a post-AGB star, but more likely a post-RGB star. The secondary is a red dwarf or possibly a low-luminosity white dwarf, which orbits the primary every 150-200 days. The system is surrounded by a slowly rotating circumbinary disk, probably with a face-on orientation towards the solar system and a size of about 150 astronomical units.
Variability
In 1991, Jean Manfroid et al. published photometry that showed that HD 101584 is a variable star.
HD 101584 has been given the variable star designation V885 Centauri. The International Variable Star Index states that the star varies between visual magnitude 6.90 and 7.02, over a period of 87.9 days. However Koen and Eyer detected, in the star's Hipparcos data, an oscillation of the star's brightness with a period of 6.744 days and an amplitude of only 0.02 magnitudes.
Nebula
The Hubble Space Telescope image shows a diffuse circumstellar environment with a circular ring around HD 101584. ALMA mapped the nebula around HD 101584 and was able to map the region close to the central binary. The nebula consists of a central compact source, an equatorial density enhancement (disk), a high-velocity bipolar outflow and an hourglass structure surrounding the outflow. The outflow reaches a maximum velocity of about 150 km/s and is inclined to the line of sight by °. There is evidence for a second bipolar outflow with a different orientation from the major outflow. The inner disk, heated to 1540 K, currently has been sublimated by the increasing luminosity of the star.
Evolution
The companion of this system was captured a few hundred years ago, for example when the red giant reached its critical size. It spiralled towards the red giant but stopped before it merged with the core of the primary. During this stage the outer layers of the red giant were ejected. During the common envelope phase the red giant phase of the primary was terminated and the core was revealed. Later, the bipolar jets formed and met the ejected material, forming the hourglass-shaped structure. Ejected material shows prominent spectral features of magnesium, while outer ejected structures contain methanol and formaldehyde.
References
Binary stars
Protoplanetary nebulae
Centauri, V885
046992
IRAS catalogue objects
J11405880-5534258
A-type supergiants
Variable stars
101584
Centaurus | HD 101584 | Astronomy | 568 |
18,582,715 | https://en.wikipedia.org/wiki/Conductor%20%28ring%20theory%29 | In ring theory, a branch of mathematics, the conductor is a measurement of how far apart a commutative ring and an extension ring are. Most often, the larger ring is a domain integrally closed in its field of fractions, and then the conductor measures the failure of the smaller ring to be integrally closed.
The conductor is of great importance in the study of non-maximal orders in the ring of integers of an algebraic number field. One interpretation of the conductor is that it measures the failure of unique factorization into prime ideals.
Definition
Let A and B be commutative rings, and assume . The conductor of A in B is the ideal
Here is viewed as a quotient of A-modules, and denotes the annihilator. More concretely, the conductor is the set
Because the conductor is defined as an annihilator, it is an ideal of A.
If B is an integral domain, then the conductor may be rewritten as
where is considered as a subset of the fraction field of B. That is, if a is non-zero and in the conductor, then every element of B may be written as a fraction whose numerator is in A and whose denominator is a. Therefore the non-zero elements of the conductor are those that suffice as common denominators when writing elements of B as quotients of elements of A.
Suppose R is a ring containing B. For example, R might equal B, or B might be a domain and R its field of fractions. Then, because , the conductor is also equal to
Elementary properties
The conductor is the whole ring A if and only if it contains and, therefore, if and only if . Otherwise, the conductor is a proper ideal of A.
If the index is finite, then , so . In this case, the conductor is non-zero. This applies in particular when B is the ring of integers in an algebraic number field and A is an order (a subring for which is finite).
The conductor is also an ideal of B, because, for any in and any in , . In fact, an ideal J of B is contained in A if and only if J is contained in the conductor. Indeed, for such a J, , so by definition J is contained in . Conversely, the conductor is an ideal of A, so any ideal contained in it is contained in A. This fact implies that is the largest ideal of A which is also an ideal of B. (It can happen that there are ideals of A contained in the conductor which are not ideals of B.)
Suppose that S is a multiplicative subset of A. Then
with equality in the case that B is a finitely generated A-module.
Conductors of Dedekind domains
Some of the most important applications of the conductor arise when B is a Dedekind domain and is finite. For example, B can be the ring of integers of a number field and A a non-maximal order. Or, B can be the affine coordinate ring of a smooth projective curve over a finite field and A the affine coordinate ring of a singular model. The ring A does not have unique factorization into prime ideals, and the failure of unique factorization is measured by the conductor .
Ideals coprime to the conductor share many of pleasant properties of ideals in Dedekind domains. Furthermore, for these ideals there is a tight correspondence between ideals of B and ideals of A:
The ideals of A that are relatively prime to have unique factorization into products of invertible prime ideals that are coprime to the conductor. In particular, all such ideals are invertible.
If I is an ideal of B that is relatively prime to , then is an ideal of A that is relatively prime to and the natural ring homomorphism is an isomorphism. In particular, I is prime if and only if is prime.
If J is an ideal of A that is relatively prime to , then is an ideal of B that is relatively prime to and the natural ring homomorphism is an isomorphism. In particular, J is prime if and only if JB is prime.
The functions and define a bijection between ideals of A relatively prime to and ideals of B relatively prime to . This bijection preserves the property of being prime. It is also multiplicative, that is, and .
All of these properties fail in general for ideals not coprime to the conductor. To see some of the difficulties that may arise, assume that J is a non-zero ideal of both A and B (in particular, it is contained in, hence not coprime to, the conductor). Then J cannot be an invertible fractional ideal of A unless . Because B is a Dedekind domain, J is invertible in B, and therefore
since we may multiply both sides of the equation by J −1. If J is also invertible in A, then the same reasoning applies. But the left-hand side of the above equation makes no reference to A or B, only to their shared fraction field, and therefore . Therefore being an ideal of both A and B implies non-invertibility in A.
Conductors of quadratic number fields
Let K be a quadratic extension of Q, and let be its ring of integers. By extending to a Z-basis, we see that every order O in K has the form for some positive integer c. The conductor of this order equals the ideal cOK. Indeed, it is clear that cOK is an ideal of OK contained in O, so it is contained in the conductor. On the other hand, the ideals of O containing cOK are the same as ideals of the quotient ring . The latter ring is isomorphic to by the second isomorphism theorem, so all such ideals of O are the sum of cOK with an ideal of Z. Under this isomorphism, the conductor annihilates , so it must be .
In this case, the index is also equal to c, so for orders of quadratic number fields, the index may be identified with the conductor. This identification fails for higher degree number fields.
References
See also
Integral element
Ring theory
Commutative algebra | Conductor (ring theory) | Mathematics | 1,272 |
64,804,657 | https://en.wikipedia.org/wiki/2016%20%28number%29 | 2016 is the natural number following 2015 and preceding 2017.
Mathematics
2016 is the second-smallest Erdős–Nicolas number after 24. 2016 is a triangular number. 2016 has a total of 36 divisors.
References
Integers | 2016 (number) | Mathematics | 46 |
34,439,024 | https://en.wikipedia.org/wiki/California%20Building%20Standards%20Code | The California Building Standards Code is the building code for California, and Title 24 of the California Code of Regulations (CCR). It is maintained by the California Building Standards Commission which is granted the authority to oversee processes related to the California building codes by California Building Standards Law. Code amendments are proposed by the California Department of Housing and Community Development. The California building codes under Title 24 are established based on several criteria: standards adopted by states based on national model codes, national model codes adapted to meet California conditions, and standards passed by the California legislature that address concerns specific to California.
Title 24 of the California Code of Regulations consist of 13 parts:
Part 1-California Administrative Code
Part 2-California Building Code
Part 2.5-California Residential Code
Part 3-California Electrical Code
Part 4-California Mechanical Code
Part 5-California Plumbing Code
Part 6-California Energy Code (this section is commonly known as “Title 24” in the construction trade)
Part 7- Reserved
Part 8-California Historical Building Code
Part 9-California Fire Code
Part 10-California Existing Building Code
Part 11-California Green Building Standards Code (also referred to as CALGreen)
Part 12-California Referenced Standards Code
Portions of editions of the California building codes are published by the International Code Council (ICC), National Fire Protection Association (NFPA), International Association of Plumbing and Mechanical Officials (IAPMO), and BNi Building News. As they are, in effect, amended versions of copyright works such as the International Building Code (IBC) maintained by the International Code Council (ICC), the regulations have substantial portions under copyright, and hence may be withheld from the public or individuals, but still have the force of law. In 2008, Carl Malamud published the California Building Standards Code on Public.Resource.Org for free.
Code adoption cycle
New editions of the California Building Standards Code are published every three years in a triennial cycle with supplemental information published during other years. Publication of triennial editions of the CCR began in 1989. The most recent version of the code was the 2019 edition published January 1, 2020. Changes made to each edition are based on proposals made by state agencies. Proposals are presented to the California Building Standards Commission and must provide thorough justification for proposed changes. Proposals go through multiple phases during the adoption cycle.
References
External links
California Building Standards Code
Building codes
Building Standards Code
Government of California
Standards of the United States | California Building Standards Code | Engineering | 490 |
46,254,141 | https://en.wikipedia.org/wiki/AuthaGraph%20projection | AuthaGraph is an approximately equal-area world map projection invented by Japanese architect Hajime Narukawa in 1999. The map is made by equally dividing a spherical surface into 96 triangles, transferring it to a tetrahedron while maintaining area proportions, and unfolding it in the form of a rectangle: it is a polyhedral map projection. The map substantially preserves sizes and shapes of all continents and oceans while it reduces distortions of their shapes, as inspired by the Dymaxion map. The projection does not have some of the major distortions of the Mercator projection, like the expansion of countries in far northern latitudes, and allows for Antarctica to be displayed accurately and in whole. Triangular world maps are also possible using the same method. The name is derived from "authalic" and "graph".
The method used to construct the projection ensures that the 96 regions of the sphere that are used to define the projection each have the correct area, but the projection does not qualify as equal-area because the method does not control area at infinitesimal scales or even within those regions.
The AuthaGraph world map can be tiled in any direction without visible seams. From this map-tiling, a new world map with triangular, rectangular or a parallelogram's outline can be framed with various regions at its center. This tessellation allows for depicting temporal themes, such as a satellite's long-term movement around the Earth in a continuous line.
In 2011 the AuthaGraph mapping projection was selected by the Japanese National Museum of Emerging Science and Innovation (Miraikan) as its official mapping tool. In October 2016, the AuthaGraph mapping projection won the 2016 Good Design Grand Award from the Japan Institute of Design Promotion.
On April 16, 2024, Nebraska Governor Jim Pillen signed a law that requires public schools to use only maps based on the Gall–Peters projection, a similar cylindrical equal-area projection, or the AuthaGraph projection, beginning in the 2024–2025 school year.
See also
List of map projections
Lee conformal world in a tetrahedron, another tetrahedral projection, 1965
Dymaxion map, 1943
Peirce quincuncial projection, 1879
Polyhedral map projection, earliest known is by Leonardo da Vinci, 1514
References
External links
Good Design Award
1999 introductions
Map projections
Japanese inventions | AuthaGraph projection | Mathematics | 483 |
76,537,354 | https://en.wikipedia.org/wiki/Mountain%20soap | Mountain soap (, , ), rock-soap or bolus — a partially outdated trivial name for a large group of clay minerals similar in properties from the group of hydrous layered aluminum silicates with variable composition. Minerals from the mountain soap group contain primarily silicates (44-46%), alumina (17-26%), iron oxides (6-10%) and water (13-25%). The mountain soap group included at different times up to two dozen mineral species and varieties. In different cases, this name could mean different minerals, most often halloysite (from the proper name), saponite (soapstone), bentonite or montmorillonite (from the , toponym). The last mineral is a large group, each of which could be called mountain soap. All these minerals received their common colloquial name, which gradually penetrated into mineralogy, for their ability to lather and serve as a detergent for various purposes.
Mountain soap has some common properties that are characteristic of all minerals included in the group. All of them have very low hardness (from 1 to 2 on the Mohs scale) and are a typical weathering product of aluminosilicates. In the form of its main component (bentonite, which is formed during the weathering of volcanic rocks — tuffs and ash), mountain soap is one of the main minerals in many types of soils, and it is also found in many sedimentary rocks. Thanks to its layered "batch" structure, mountain soap has the ability to absorb water, swell strongly and has pronounced sorption properties.
Name
The name "mountain soap" is not so much a metaphor, which is quite often found in mineralogy, as a simple statement of the soapy properties of the mineral, as well as the systematic use that it has had for thousands of years. This mineral is named mountain soap, on account of its greasiness, sectility, and softness. On the one hand, this type of clay received its trivial name from its property of softening in water and forming with it a viscous and greasy substance to the touch, similar to thickly diluted soap. On the other hand, for a very long time, the population that had access to deposits of such clays systematically used it as a detergent for various purposes: from waulking cloth, canvas and wool to washing hands, face and hair in the bathhouse. From the combination of two factors inherent in all these varieties, other synonymous names also follow under which washing clays are found. In the literature of the 18th and 19th centuries, mountain soap can be found under the names: soapy earth, soapy clay, soapstone or bolus.
The conventional scientific use of the collective term "mountain soap" generally ended by the last quarter of the 19th century, giving way to individual names of the minerals included in this conventional group. Currently, the term is considered completely outdated and does not appear as such even in the latest mineralogical dictionaries.
Properties
Mountain soap has the same properties as one of its main varieties: bentonite or montmorillonite. This is a typical clay mineral belonging to the subclass of layered silicates, due to its structure it has the ability to swell strongly. In addition, mountain soap has pronounced sorption properties. The modern use of bentonites in industrial production, construction and even as a food additive is based on their high thermal stability, binding ability, as well as catalytic and adsorption activity.
Old authors of the 18th-19th centuries, describing the properties of mountain soap, unanimously note that it is opaque, not sticky, convenient for writing, and also soft when wetted, lathers well and sticks strongly to the tongue. It feels greasy and light. In composition (according to Buchholz's analysis) it contains 44% silica, 26.5% alumina, about 20.5% water, 8% iron oxides and 0.5-1% calcium compounds (lime). Naturally, the results of chemical analysis relate exclusively to the specific variety on which laboratory operations were carried out. In all other cases, both the percentage composition of the substances that make up the clay and the set of impurities may differ significantly from the proposed ratio. Nevertheless, this analysis is quite indicative in general for that mineral group that can be described as "mountain soaps".
Being in damp soil or being moistened, mountain soap becomes completely soft and similar to butter, but when it dries in dry weather in the air or when heated, it hardens. Chemical stability and even some inertness of mountain soap are also noted; even in strong acids, for example, sulfuric, hydrochloric or nitric, no visible change or any other signs of a chemical reaction occur with it.
The authors differ significantly more regarding the color of the clays. If Johann Gottgelf von Waldheim unequivocally states that mountain soap "has a light pitch-black color", Pavel Goryaninov practically confirm his opinion, assuring that it is "black-brown in color", and Robert Jameson confirms this information, however then other authors are much less categorical. The Mining Journal for 1926 writes that "this soap has different colors, but more greenish and yellow", and in the Mining Dictionary of 1843 summarizes: "its color is generally white, turning into dark brown, bluish and yellowish".
It is clear that the specific characteristics of mountain soap are associated, first of all, with the breadth of coverage of regional forms and varieties that a particular author included in his review. In particular, Spassky separately mentions that the external properties of mountain soap, used in the Kazan and Irkutsk governorates, and especially in the Crimea under the name kil, are generally similar to those described here, however, the chemical composition of each of these differences has not yet been precisely determined.
Pavel Ogorodnikov writes about exactly the same thing in his memoir "Essays on Persia", of course, without mentioning the exact names and chemical terms. Talking about his travels through Northern Iran, he notices that different types of fatty clay, which replaces soap for the poor population when washing clothes, are found in abundance in all the nearby mountains. For example, grayish clay, sold at the local market for 1,80 rub. and more expensive per halvar, mined mainly between the villages of Tash and Mujen, and cheaper, yellowish (90 kopecks per halvar) — in the surrounding mountains of the village of Taal-Saab-abad. Asterabad residents wash their clothes mainly with Gilaser clay, which is abundant in the Asterabad mountains. In addition, the Shahrud people also use Semnon clay, which comes from the city of Semnon, which lies on the way from Shahrud to Tehran. This particularly expensive and probably high quality clay sells for 9 rub. for halvar, used exclusively by women when washing their hair in the bathhouse.
Gallery
References
See also
Mountain (disambiguation)
Soap (disambiguation)
Kaolinite
Clay
Set index articles on minerals
Aluminium minerals
Silicate minerals
Food additives
Rocks
Cleaning products
Monoclinic minerals
Mining terminology
Mineral groups | Mountain soap | Physics,Chemistry | 1,506 |
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