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Astronomic Trignometry : Vedic Astronomy & Trignometry
In the Great Circle of Light which is 360 degrees, ( the Bha Chakra, the Kala Chakra, the Zodiac ), the first 90 degrees are Oja Pada ( Odd Tri Signs ) and the next 90 degrees are Yugma Pada ( Even Tri Signs ). The degrees traversed by a planet is called Bhuja and the degrees yet to be traversed by a planet is called Koti in an Oja Pada. In a Yugma Pada, the degrees traversed by the planet is called Koti and the degrees yet to be traversed by a planet is called Bhuja. In other words, the degrees traversed by a planet is the same in the first 0 - 90 degrees and in the second Pada, it is 180 - degrees traversed. In the 180-270 degrees arc, it is distance traversed - 180 degrees and in the 270-360 degrees arc, it is 360 - distance traversed. This is known in Vedic Astronomy as the equation of Bhuja or Sin. Bhujajya is radius multiplied by modern Sine.
In the Mighty Circle of Light
The First 90 degrees is Oja called
The distance traversed is Bhuja called
Koti is the untraversed degree !
( Oja Yatra Bhujaira Kotirapara Meshadi Jookadhi Kau )
Brahmagupta, in his mathematical treatise, the Brahmasphuta Siddhanta used the word Jya which means 5 degrees of a 360 degree circle which is the Zodiac, which is the Ecliptic. Suppose a planet has traversed 42 degrees in the first Oja Pada ( From Aries to Gemini end ).The Bhuja is 42 degrees and the Bhujajya is the 9th Jya or the 9*5 th degree. Bhujajya by Trijya is Opposite Side by Hypotenuse or the modern Sine.
Jya Ganitha means Trignometry. The equation for Koti is different. It is Kotijya by Trijya or Adjacent Side by Hypotenuse ( the modern Cos ). As per Indian Learning it was Aryabhata, one of the greatest mathematicians ever, who first computed the celestial longitudes of planets ( Aryabhato Graha Ganitham ).
The calculations given for the perturbations of Moon, Jupiter and Saturn are as follows. First find out the Bhuja of the planet, the degrees traversed. Find out its Bhujajya or Sin ( Bhuja ). Multiply it by the value given ( which is in seconds) and add it to the mean longitude of the planet.
Meshadi , Thuladi, Karkyadi & Makaradi ( The First Points of Aries, Cancer, Libra & Capricorn )
From Aries to Libra is the Northern Celestial Hemisphere ( NCH ) and from Libra to Aries is the Southern Celestial Hemisphere ( SCH ). If the planet's Kendra is in NCH, the values are to be subtracted and if in the SCH, it is to be added.
Karkyadi is the First Point of Cancer and the beginning of Dakshinayana, the Southern course of the Sun, his declination South. Makaradi is the First Point of Capricorn and the beginning of Uttarayana, the Northern course of the Sun , his declination North. At Meshadi, the Sun's declination is 0 degrees and Right Ascension is 0 degrees. At Karkyadi, the Sun's declination is +23 degrees 27 minutes and Right Ascension is 90 degrees. At Thuladi, the Sun's declination is 0 degrees and Right Ascension is 180 degrees. At Makaradi, the Sun's declination is -23 degrees 27 minutes and Right Ascension is 270 degrees.
The Perturbations of Jupiter
The equations given for Jupiter's perturbations are as follows: Five major perturbations are included along with a major perturbation which is given below. ( The great Jupiter - Saturn perturbation ).
Kendra means an angle in Sanskrit . Manda Kendra means Mean Anomaly, the angle between position and perihelion and Sheeghra Kendra is the last angle formed before the ultimate reduction to perihelion. All Kendras are zero at perihelion.
The English Era + 3102 gives the Kali Era, the Era of the Hindu Calender. From that value 4660 is deducted and the value is divided by 918. This gives the Beeja Kendra. Find out the Sin ( Bhuja ) of that, multiply it with 1187 seconds and add it to Jupiter's longitude if the Kendra is in NCH and subtract it if it is in SCH.
There are other minor perturbations which can be ignored.
( Lj = Mean Longitude of Jupiter; Ls - Mean Longitude of Saturn. These longitudes are Tropical or Sayana. ).
First Kendra (Sin ( Lj - Ls ) - 1. 15)* 81
Second Kendra Sin (( Lj - 2 Ls) - 13.08 )* 132
Third Kendra Sin ( 2 Lj - 2 Ls - 0.58 )* 200
Fourth Kendra Sin ( 2 Lj - 3 Ls - 61.57 )* 83
Fifth Kendra Sin ( 3 Lj - 5 Ls - 56.38 )* 162
The first value is to be added if the Kendra is Thuladi ( after the First Point of Libra ) and deducted if it is Meshadi ( after the First Point of Aries ). 2,3,4 & 5 are to be added if it is Meshadi and subtracted if Thuladi
The Perturbations of Saturn
First Kendra Sin ( Lj - 2 Ls ) -14.66 )*418
Second Kendra Sin ( 2 Lj - 4 Ls + 56.90 )* 667
Third Kendra Sin ( 3Ls - Lj + 77.38 )* 48
These values are to be added if the Kendra is Thuladi ( after the First Point of Libra ) and deducted if it is Meshadi ( after the First Point of Aries ). In Sanskrit it is called Meshadi Rinam & Thuladi Dhanam. Meshadi is the beginning of the Northern Celestial Hemisphere and Thuladi the begining of the Southern Celestial Hemisphere.
There are other minor perturbations which may affect only the Vikala ( second ) of the planet's longitude and hence can be ignored.
The Perturbations of the Moon
(Ms - Mean Anomaly of the Sun; Mm - Mean Anomaly of the Moon; Ls - Mean Longitude of the Sun; Lm - Mean Longitude of the Moon; D = Lm - Ls ( Thidhi); Nm - Node of the Moon. These values are Sidereal or Nirayana )
14 Kendras are to be made and 14 trignometric corrections are to be given, according to astronomical savants. These 14 reductions are mandatory and only after these reductions can we get the true longitude of the Moon.
First Kendra Sin ( Ms + 180 ) * 658
Second Kendra Sin ( Lm - Ls ) * 121
Third Kendra Sin ( 2*D - Mm ) * 4467
Fourth Kendra Sin ( 2*D + 6 Signs ) * 2145
Fifth Kendra Sin (( 2*D - Mm -Ms ) + 180)* 198
Sixth Kendra Sin ( 2*D - Ms ) * 155
Seventh Kendra Sin ( Mm- Ms + 180 ) *112
Eighth Kendra Sin ( 2( Lm - Nm- Mm +180))* 85
Ninth Kendra Sin ( 2*Ls - Nm ) * 81
Tenth Kendra Sin ( Mm - Ms )* 73
Eleventh Kendra Sin ( 2*D + Mm ) * 60
Twelfth Kendra Sin ( 2*Mm - 2 D + 180 ) * 42
Thirteenth Kendra Sin ( 4*D - Mm ) * 35
Fourteenth Kendra Sin ( 4*D - 2*Mm +180)* 30
These trignometric corrections should be added to Moon's Mean Longitude if the Kendra is in the Southern Celestial Hemisphere and deducted if the Kendra is in the Northern Celestial Hemisphere and then we get the Samskrutha Chandra Madhyamam or the Cultured Mean Longitude of the Moon. Manda Kriya ( Reduction to True Anomaly ) must be done. Then Parinathi Kriya ( Reduction to Ecliptic ) should be done and what we get then is the longitude of the Moon along the Ecliptic !
Viskshepa Vrittopa Gatho Vipatha
Thasmannayel Jyam Parinathyabhikhyam
Yugmaupada Swarnam Idam Vidheyam
Syath Kranti Vritteeya Ihaisha Chandra !
After the Reductions Fourteen, Sin M to be added or minussed thereby
To the Cultured Longitude Mean; The Node to be deducted &
Reduced to the Earth's Path ( Ecliptic ); thus shall we get as the resultant Value,
Luna's true Sidereal Longitude ! | <urn:uuid:7db7a4d3-6774-40a3-ba31-e6b24c15a2ec> | 2.953125 | 2,015 | Tutorial | Science & Tech. | 61.851454 | 95,594,618 |
As you said,
dplyr reuses variables. As a result your
initial code is trying to calculate a standard deviation from just one
value. When you look at the formula for the standard deviation:
you can see that the denominator of the formula will have a
0, which causes the
In your second
dplyr code, the standard devation is
calculated from the original variable. As the groups for which a
sd is calculated have
n > 1, the denominator
in this case is larger than zero which will result in a
dplyr just takes the last created instance of a variable.
In the page @baptiste linked to, you can find this statement of Hadley Wickham from which you can
conclude that it's better to use new names when creating new variables.
I think this behavior should be stated explicitly in the | <urn:uuid:6c996fa9-a587-4c1b-ab86-e5a3f5ec0f68> | 2.65625 | 184 | Q&A Forum | Software Dev. | 47.889286 | 95,594,619 |
Washington: For the first time, researchers have successfully bred and raised a rare and threatened Caribbean coral species in the lab.
Researchers plan to 'out-plant' these lab-grown juveniles in the wild which could help populations become more resilient to climate change.
The Caribbean Pillar Coral Dendrogyra cylindrus is rare and understudied, and small juveniles of this species have never been seen in over 30 years of surveys in the Caribbean.
Pillar Corals form a unique 'smoke stack' shape like no other coral species, and they display unusual mating behaviour compared to most spawning coral species.
Most spawning corals are hermaphrodites that release large bundles of eggs and sperm. Pillar corals, which only spawn on a few specific nights of the year, build colonies that are either all-male or all-female.
The males first release sperm into the seawater, shortly followed by the females releasing their individual eggs. This makes collection and breeding research extremely difficult.
"Now that we've successfully reared juvenile Pillar Corals in the lab, not only can we study them in more detail to find out what factors could be threatening their survival in the wild, but it also means that we can try to out-plant a small number back to the reef," said lead author Kristen Marhaver from the Caribbean Research and Management of Biodiversity (CARMABI) Foundation.
"We don't know if this will work and it is certainly not a cure-all for the reef.
"But especially in such a rare coral species, a tiny boost of a few new individuals could make a big difference in their genetic diversity, allowing their populations to adapt and become more resilient to the changing environment in the oceans," said Marhaver, who began this work while she was a postdoctoral researcher at the University of California at Merced.
After studying the sunset times and lunar cycles taken from other spawning observations, the research team timed their egg and sperm collection around the most likely annual spawning times - exactly three nights after the August full moon and around 100 minutes after sunset.
At depths of 6-7 metres on a Curacaoan coral reef with a large population of Pillar Corals, the team arranged nets and funnels over the female colonies to automatically collect eggs, and used syringes near the male colonies to manually collect sperm from spawn clouds as they appeared.
The team then attempted to fertilise the eggs by mixing the collected eggs and sperm underwater and on shore.
In the lab, the team carefully adjusted several factors related to fertilisation times and seawater type and nurtured the eggs to develop into larvae.
They managed to successfully grow the embryos to the swimming larvae stage and settled them onto ceramic tripods in water tanks. The settled juveniles then survived for over seven months. | <urn:uuid:9aeca00e-dbf1-4a45-be3f-9e930383a6b5> | 3.828125 | 577 | News Article | Science & Tech. | 32.902451 | 95,594,633 |
Ecology is the study of intricate interactions among living and nonliving things and their environment, and the balance of ecology helps determine the very health and well-being of our planet. Designing experiments around something as complex as ecology might sound overwhelming. But ecology embraces many fascinating areas of science, including ecosystem ecology, animal behavior, population ecology and physiological ecology.
An ecosystem consists of the living, or biotic, and nonliving, or abiotic, parts of an interrelated community. Abiotic aspects of an ecosystem include soil, air, water, sunlight and the chemistry of soil and water. Biotic components include plants, herbivores, carnivores and detrivores. To illustrate how an ecosystem works, try building two or more identical miniature land or water ecosystems in a large covered jar or aquarium. Provide the necessary components of a typical ecosystem, including edible plants, soil, small herbivores, detrivores, pond water, air and a light source. Alter one factor in the ecosystem, such as the amount of light or water it receives, while keeping all other factors the same to see what changes occur in the mini ecosystem. Observe the interactions between organisms and test for changes in animal health, water acidity and other detectable changes.
The animals around us are entertaining and fascinating to observe. Using a bit of scientific discipline, it is possible to turn those observations into a science experiment. Try setting up clear glass hummingbird feeders containing sugar water in different colors and observe which feeders the birds seem to prefer. What connection might this have to the adaptations the hummingbird has developed to survive in its environment?
Population ecology examines factors that affect the population of a species of animal, such as food availability, temperature, predators or overcrowding. To do a population ecology study, tally a food source -- for example, plants -- in a measured area and record changes over time in the population of consumers. Or place different numbers of a species of plant or small animal -- for example, duck weed or crickets -- in two or more identical mini aquariums or terrariums. Provide them the same amounts of food, space and light, and then observe how population density affects their population growth.
A physiological ecologist studies how an organism's body is adapted to its environment and how changes in the environment -- such as temperature, chemicals or resource availability -- affect it. To study the physiological ecology of an organism, design an experiment to observe the effect of rising temperatures -- such as those caused by climate change -- on the growth of that organism in a controlled laboratory environment. Or observe the effects of acid rain on a species of plant in a laboratory setting, using vinegar in water to simulate rain acidity caused by coal-burning power plants. | <urn:uuid:0633eeb1-0216-4d69-9278-10736f84e431> | 4.03125 | 555 | Knowledge Article | Science & Tech. | 15.87801 | 95,594,635 |
One common way of studying the role of genes in cells is to remove a gene and investigate the effect of the loss. Genes are very similar in both yeast and people, which is one reason why the baker’s and brewer’s yeast Saccharomyces cerevisiae has become a firm favourite with geneticists – and in yeast it is easy to make this kind of genetic change.
However, this does not work for many genes as the loss causes the cells to die. These are known as essential genes and are therefore difficult to study. This is a major problem for researchers as essential genes are often involved in crucial life processes. These essential genes are also the most well-conserved over long evolutionary distances, like between humans and yeast.
Together with researchers from the University of Toronto, Anders Blomberg and Jonas Warringer from the University of Gothenburg’s Department of Cell- and Molecular Biology have produced a collection of nearly 800 strains of yeast cells where the function of these essential genes can be studied. This new genetic tool is now being made available to other researchers.
“The trick is to use temperature-sensitive mutants for the genes you want to study,” says professor Anders Blomberg. “These mutants have amino acid changes, which make the resultant protein sensitive to higher temperatures but able to function normally at normal temperatures. And at intermediary temperatures one can set the desired activity of the mutant protein.”
The Gothenburg researchers have worked for many years on characterising the changes in yeast mutants that result from genetic changes or environmental factors automatically and on a large scale. They will continue to develop and characterize the new collection of yeast cells to facilitate the systematic analysis of the function of all essential genes.
The applications of this genetic tool are exemplified in an article published in the scientific journal Nature Biotechnology.
Authors: Zhijian Li, Franco J Vizeacoumar, Sondra Bahr, Jingjing Li, Jonas Warringer, Frederick S Vizeacoumar, Renqiang Min, Benjamin VanderSluis, Jeremy Bellay, Michael DeVit, James A Fleming, Andrew Stephens, Julian Haase, Zhen-Yuan Lin, Anastasia Baryshnikova, Hong Lu, Zhun Yan, Ke Jin, Sarah Barker, Alessandro Datti, Guri Giaever, Corey Nislow, Chris Bulawa, Chad L Myers, Michael Costanzo, Anne-Claude Gingras, Zhaolei ZhangFor more information, please contact:
email@example.comJonas Warringer, Department of Cell- and Molecular Biology, University of Gothenburg, tel: +46 (0)31 786 3961
Helena Aaberg | idw
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
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19.07.2018 | Life Sciences | <urn:uuid:dae3ecf4-748a-4401-b828-0cc843a8dad1> | 3.625 | 1,219 | Content Listing | Science & Tech. | 35.266246 | 95,594,636 |
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Peptide computing is a form of computing which uses peptides and molecular biology, instead of traditional silicon-based computer technologies. The basis of this computational model is the affinity of antibodies towards peptide sequences. Similar to DNA computing, the parallel interactions of peptide sequences and antibodies have been used by this model to solve a few NP-complete problems. Specifically, the hamiltonian path problem (HPP) and some versions of the set cover problem are a few NP-complete problems which have been solved using this computational model so far. This model of computation has also been shown to be computationally universal (or Turing complete).
This model of computation has some critical advantages over DNA computing. For instance, while DNA is made of four building blocks, peptides are made of twenty building blocks. The peptide-antibody interactions are also more flexible with respect to recognition and affinity than an interaction between a DNA strand and its reverse complement. However, unlike DNA computing, this model is yet to be practically realized. The main limitation is the availability of specific monoclonal antibodies required by the model.
|This computer science article is a stub. You can help Wikipedia by expanding it.| | <urn:uuid:4d484959-43e1-48c7-8e73-4a91952d8246> | 2.90625 | 284 | Knowledge Article | Science & Tech. | 21.884264 | 95,594,637 |
|Scientific Name:||Acropora palmata (Lamarck, 1816)|
|Red List Category & Criteria:||Critically Endangered A2ace ver 3.1|
|Assessor(s):||Aronson, R., Bruckner, A., Moore, J., Precht, B. & E. Weil|
|Reviewer(s):||Livingstone, S., Polidoro, B. & Smith, J. (Global Marine Species Assessment)|
This species is listed as Critically Endangered as there has been a population reduction exceeding 80% over the past 30 years due, in particular to the effects of disease, as well as other climate change and human-related factors. This species is particularly susceptible to bleaching. Although the current population is persisting at a very low abundance and the current population trend appears to be stable, there are places where populations continue to decrease and others where there seems to be moderate or localized recovery. Whether mortality continues to exceed growth and recruitment or not, this species requires immediate investigation and monitoring on a regional scale.
|Range Description:||This species occurs in the Caribbean, the Gulf of Mexico, Florida, and the Bahamas. While A. cervicornis has been documented further north along the Florida east coast, the northern extension of A. palmata is at Fowey Rocks offshore the Miami area (25°37’ N) (Porter et al. 1987).|
Native:Anguilla; Antigua and Barbuda; Bahamas; Barbados; Belize; Bonaire, Sint Eustatius and Saba (Saba, Sint Eustatius); Cayman Islands; Colombia; Costa Rica; Cuba; Curaçao; Dominica; Dominican Republic; Grenada; Guadeloupe; Haiti; Honduras; Jamaica; Mexico; Montserrat; Nicaragua; Panama; Saint Barthélemy; Saint Kitts and Nevis; Saint Lucia; Saint Martin (French part); Saint Vincent and the Grenadines; Sint Maarten (Dutch part); Trinidad and Tobago; Turks and Caicos Islands; United States; United States Minor Outlying Islands; Venezuela, Bolivarian Republic of; Virgin Islands, British
|FAO Marine Fishing Areas:|
Atlantic – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||There has been an 80-98% loss of individuals in parts of the Caribbean since the 1980s. There have been some signs of recovery. A second report has validated declines on the order of 97% in the Florida Keys, Jamaica, Dry Tortugas, Belize and St Croix (Acropora BRT 2005) and Puerto Rico (Weil et al. 2003).|
There are signs of recovery in populations in some localities. For example, populations in St Croix showed increases from 2001-2003, although larger colonies are not surviving, as large colonies are more affected by stressors (Grober-Dunsmore et al. 2006). Similarly, there are signs of recovery in Puerto Rico and other parts of the southern Caribbean (E. Weil pers. comm.). However, some of these same populations have undergone subsequent declines.
Overall, decline of destroyed and critical reefs in the Caribbean region has been 38% (according to Wilkinson 2004) however there have been much higher population reductions for this species as it is particularly susceptible to disease and bleaching.
The age of first maturity of most reef building corals is typically three to eight years (Wallace 1999) and therefore we assume that average age of mature individuals is greater than eight years. Furthermore, based on average sizes and growth rates, we assume that average generation length is 10 years, unless otherwise stated. Total longevity is not known, but likely to be more than ten years. Therefore any population decline rates for the Red List assessment are measured over at least 30 years. See the Supplementary Material for further details on population decline and generation length estimates.
|Current Population Trend:||Stable|
|Habitat and Ecology:||This species is found in shallow tropical reef ecosystems, favouring outer reef slopes exposed to wave action. It has been recorded to depths of 22 m at Flower Garden Banks in the Gulf of Mexico (Zimmer et al. 2005), but this is a recent range extension potentially due to the results of climate change (Precht and Aronson 2004). The normal depth range is 0.5-5 m (Goreau and Wells 1967), but it can be found up to 40 m.|
This species has limited sexual recruitment.
The major threat to this species has been disease, specifically white-band disease which is believed to be the primary cause for the region wide acroporid decline during the 1980s (Aronson and Precht, 2001a,b) and is still ongoing (Williams and Miller, 2005). Other major threats include thermal-induced bleaching, storms, and other diseases (Rodriguez-Martinez et al. 2001,Precht et al. 2002,Patterson et al. 2002, Acropora BRT 2005).
Localized declines are associated with: loss of habitat at the recruitment stage due to algal overgrowth and sedimentation; predation by snails; mortality by endolithic sponges; ship groundings, anchor damage, trampling, and marine debris. The long-term threat of reduced skeletal integrity due to ocean acidification is of particular concern due to the species' presence in wave-swept environments.
In general, the major threat to corals is global climate change, in particular, temperature extremes leading to bleaching and increased susceptibility to disease, increased severity of ENSO events and storms, and ocean acidification.
Coral disease has emerged as a serious threat to coral reefs worldwide and a major cause of reef deterioration (Weil et al. 2006). The numbers of diseases and coral species affected, as well as the distribution of diseases have all increased dramatically within the last decade (Porter et al. 2001, Green and Bruckner 2000, Sutherland et al. 2004, Weil 2004). Coral disease epizootics have resulted in significant losses of coral cover and were implicated in the dramatic decline of acroporids in the Florida Keys (Aronson and Precht 2001, Porter et al. 2001, Patterson et al. 2002). Escalating anthropogenic stressors combined with the threats associated with global climate change of increases in coral disease, frequency and duration of coral bleaching and ocean acidification place coral reefs at high risk of collapse.
Localized threats to corals include fisheries, human development (industry, settlement, tourism, and transportation), changes in native species dynamics (competitors, predators, pathogens and parasites), invasive species (competitors, predators, pathogens and parasites), dynamite fishing, chemical fishing, pollution from agriculture and industry, domestic pollution, sedimentation, and human recreation and tourism activities.
The severity of these combined threats to the global population of each individual species is not known.
Listed on CITES Appendix II and Threatened on the US Endangered Species Act. In the US, it is present in several MPAs, including Florida Keys National Marine Sanctuary, Biscayne N.P., Dry Tortugas National Park, Buck Island Reef National Monument and Flower Garden Banks National Marine Sanctuary. Also present Hol Chan Marine Reserve (Belize), Exuma Cays Land and Sea Park (Bahamas). In US waters, it is illegal to harvest corals for commercial purposes. In response to ship grounding and hurricanes, there have been efforts to salvage damaged corals and reattach them in acroporid habitats.
More information is needed to assist the recovery of acroporids including survival and fecundity by age, sexual and asexual recruitment, population information, juvenile population dynamics, importance of habitat variables to recruitment and survivorship, and location of populations showing signs of recovery (Bruckner, 2002). Further research is needed into disease etiology, and effectiveness of current restoration methods.
|Citation:||Aronson, R., Bruckner, A., Moore, J., Precht, B. & E. Weil. 2008. Acropora palmata. The IUCN Red List of Threatened Species 2008: e.T133006A3536699.Downloaded on 20 July 2018.|
|Feedback:||If you see any errors or have any questions or suggestions on what is shown on this page, please provide us with feedback so that we can correct or extend the information provided| | <urn:uuid:9c29df66-881d-4d37-a14d-5ef353056c36> | 2.828125 | 1,782 | Knowledge Article | Science & Tech. | 33.36701 | 95,594,642 |
Posted on Sep 3, 2017 7 mins read
What’s docker? I think a lot of folks that read my blog will already know what Docker is, however, I’ll give a brief explanation anyway. Docker is a wrapper around Linux Containers (LXC) written in Go. It uses some REST API’s to communicate with the docker daemon to be able to start up containers and relies on IPTables for networking along with the docker bridge.
Docker is a powerful tool because the same image I generate locally on my machine can be deployed into production, or the code can be committed and be made part of your CI/CD Pipeline. Other local development environment tools such as vagrant use virtual machines which are based on Xen, KVM, or VMWare. Unfortunately, building a vagrant box doesn’t really translate to building an image that can be deployed to AWS or Google Cloud. There are products that facilitate this like Packer (From HashiCorp as well), however, it’s a bit of a stretch to get developers to start using this, much less to start using it to bring up local environments.
|Host OS||Relatively, this is your machine or the server that has the container running on it.|
|Guest OS||This usually is reserved for virtual machines, but it’s fair to use the term when describing the operating system the container image is based on.|
|Ephemeral||Temporary or short lived.|
|Immutable||Indicates a lack of data persistence. No data is stored on something that is immutable. The underlying term actually means ‘replaceable’.|
Dockerfile The Dockerfile basically describes how to build your image. Dockerfiles are relatively simple. In fact, here’s the entire reference for Dockerfile, take a quick glance over it. You can do simple things like exposing ports to the host OS (making things externally accessible), you can attach volumes that can add persistence to Docker (Docker and Linux Containers are ephemeral and immutable by nature), you can add existing directories, etc… The Dockerfile is the quintessential for building custom images that run on Docker containers.
docker-compose Docker has an accompanying application called docker-compose. If you’re using OSX then the install for Docker already comes with it, if you’re using Linux or Windows you’ll need to download it separately.
Rarely do we ever just run one application by itself. Frequently we need to run an application, a data source, and any other piece of infrastructure it may be dependent on. In this example I’m going to use a real Dockerfile and docker-compose that I wrote for a FOSS project I’ve been working on. The docker-compose is yaml based and represents various container and images pairs as services.
Building our Dockerfile The framework I’m using is called Django which is python based. All I need is an OS with Python 3. All publicly available Docker images are based on some type of OS with all the non-essentials removed.
ENV sets an environment variable in Key Value format. If you had multiple you’d use multiple ENV’s.
RUN This indicates executes a command using the default shell. We’re making the preliminary directory called code in the root of the guest OS (note the prefixed slash).
WORKDIR Changes the working directory to
/code. The commands using this context are specific to
ADD Copies a file to your Docker image. You might’ve noticed there’s a command called
COPY that is remarkably similar to
ADD. There’s two key differences.
<src>to be a url.
RUN I need pip to process my requirements.txt. We’re executing a normal shell command here, just as if we were sitting at the terminal.
ADD We’re now copying my existing code repository to Docker image.
That’s it! If all we wanted to do was build the image and run the container then Django would come up. You’d simply:
docker build .
This indicates to docker: Build my image, search for the Dockerfile in this directory (.)
docker create <image id>
At this point your docker container would run but would not be externally accessible (we never specified
version specifies which version of the docker-compose reference to use.
services Each top level is essentially a different container. Services are special because they can resolve each other by their service name. For instance, I can reach db from web by
db/image In this case I’m telling docker-compose to use the Docker Hub image for postgres. Notice there’s no label selected, Docker will assume latest.
db/environment I’m setting an environment variable in a Key: Value format. The postgres page on Docker Hub has some nice instructions on features they’ve put into the postgres image.
web/build I’m indicating to docker-compose to run a docker build in ‘.’. This will build my Docker image. If I had multiple custom images I’d just place a Dockerfile in different directories.
web/command this is the command to run when the container starts. Notice I lost my context behind
WORKDIR in the Dockerfile. There’s a way to fix this, but I wanted to point it out.
web/volumes I’m telling docker-compose that I want to mount /code as a volume. Changes I make in my code will be reflected into the container AND vice versa. I’ll get into this later.
web/ports This is the exposed port on the Host OS to the Guest OS.
web/depends_on This tells docker-compose that it can’t start the web container until the db container is online.
Using docker-compose. Before we were able to use the
docker command to build, create, run etc… Now that we’re using docker-compose though, we have to use the
docker-compose command. If you don’t, you can still reach your containers but they’ll be without some of the essential networking that docker-compose gives you.
You’ll need to create your code folder and generate a Django app, but after that simply run
docker-compose up -d. This launches docker-compose in daemon mode. Leave out
-d when you’re troubleshooting. You can run
docker-compose ps to get the names of your containers and run commands on them like this:
docker-compose run -it <container name> <command>.
Technically we’re all done, but I wanted to show you something neat. Remember how I said in docker-compose you can reference services by name and they’ll resolve? In case it didn’t click, here’s an excerpt from my Django settings.py:
My host is using ‘db’. That’s all for today, hopefully that’s helped get the gears spinning. There’s a lot more you can do with docker-compose and docker, so be sure to explore!Tutorials Docker Docker-Compose | <urn:uuid:0af4d302-4f81-438e-9feb-3c7e9b42ccb2> | 2.59375 | 1,556 | Personal Blog | Software Dev. | 54.032293 | 95,594,649 |
Data Structures and Algorithms with Object-Oriented Design Patterns in Ruby
This book was motivated by my experience in teaching the course E&CE 250: Algorithms and Data Structures in the Computer Engineering program at the University of Waterloo. I have observed that the advent of object-oriented methods and the emergence of object-oriented design patterns has lead to a profound change in the pedagogy of data structures and algorithms. The successful application of these techniques gives rise to a kind of cognitive unification: Ideas that are disparate and apparently unrelated seem to come together when the appropriate design patterns and abstractions are used.
Pretend that you?ve opened this book (although you probably have opened this book), just to find a huge onion right in the middle crease of the book. (The manufacturer of the book has included the onion at my request.) So you?re like, ?Wow, this book comes with an onion? (Even if you don?t particularly like onions, I?m sure you can appreciate the logistics of shipping any sort of produce discreetly inside of an alleged programming manual.) Then you ask yourself, ?Wait a minute. I thought this was a book on Ruby, the incredible new programming language from Japan. And although I can appreciate the logistics of shipping any sort of produce discreetly inside of an alleged programming manual
Ruby is "an interpreted scripting language for quick and easy object-oriented programming"; what does this mean? interpreted scripting language:-ability to make operating system calls directly. powerful string operations and regular expressions
immediate feedback during development
variable declarations are unnecessary
variables are not typed
syntax is simple and consistent
memory management is automatic
Little Ruby and a Lot object
Welcome to my little book. In it, my goal is to teach you a way to think about computation, to show you how far you can take a simple idea: that all computation consists of sending messages to objects. Object-oriented programming is no longer unusual, but taking it to the extreme - making everything an object - is still supported by only a few programming languages. Can I justify this book in practical terms? Will reading it make you a better programmer, even if you never use "call with current continuation" or indulge in "metaclass hackery"? I think it might, but perhaps only if you're the sort of person who would read this sort of book even if it had no practical value.
This book is a tutorial and reference for the Ruby programming language. Use Ruby, and you'll write better code, be more productive, and enjoy programming more. These are bold claims, but we think that after reading this book you'll agree with them. And we have the experience to back up this belief. As Pragmatic Programmers we've tried many, many languages in our search for tools to make our lives easier, for tools to help us do our jobs better. Until now, though, we'd always been frustrated by the languages we were using. Our job is to solve problems, not spoonfeed compilers, so we like dynamic languages that adapt to us, without arbitrary, rigid rules. We need clarity so we can communicate using our code. We value conciseness and the ability to express a requirement in code accurately and efficiently. The less code we write, the less that can go wrong.
Ruby is a fairly new language out of Japan that apparently is very popular there. I've heard it is more popular than python there, but I haven't seen anything (yet) to confirm that rumor. Ruby is a clean, very-OO, small, well ported scripting language with a good class library. I'm really enjoying using/learning it. To review, it has full reflection mechanisms and a fairly simple syntax. Unlike python, it combines a lot of smalltalkism and perlisms which makes it very ituitive to use. As the programmatic guys say "it works the way you expect it to". I think this thing has already beat out python as far as my preferences go. It really has its shit together.
This tutorial gives an introduction to GUI programming using the Qt toolkit with QtRuby. It doesn't cover everything: the emphasis is on teaching the programming philosophy of GUI programming, and Qt's features are introduced as needed. Some commonly used features are never used in this tutorial. This little game doesn't look much like a modern GUI application. It uses a good few of the GUI techniques, but after you've worked through it, we recommend reading Tutorial #2. The second tutorial is a little more formal and covers the features of typical application including menubars, toolbars, loading and saving, dialogs, etc.
This tutorial is aimed at people that want to use Tk as toolkit with Ruby. It does not really matter whether you are very proficient in Ruby or with toolkits. Examples may overwhelm the novice sometimes, but each line is explained. Step over it and come back in a later stage. The small differences in those lines provide a wealth of information for the more experienced programmer.
A few reasons to use Tk:
Tk is supported in many places (though others are definitely catching up),
Tk may look small or simple, but is very powerful. Of course it can do all basics, like any toolkit, but some things are done in a very simple way, Its canvas has some very nice features for selecting and manipulating objects (like lines and curves) on it. It can even dump its content in a PostScript file. Tk has a few prebuilt windows like a color chooser and dialog,
Can use many Tk extensions from Ruby. | <urn:uuid:6d99515b-a847-4a23-b5af-91d835adf9e9> | 2.796875 | 1,155 | Product Page | Software Dev. | 46.275997 | 95,594,659 |
Over the last two decades, the development of plasmonics for operation around the visible spectral window has heavily relied on gold as the preferred material, mainly because of its excellent properties in terms of stability, easy chemical synthesis, and biocompatibility.126.96.36.199.–6 Already in these high-frequency ranges, however, other metals have sometimes been preferred when it comes to specific spectral regions, in particular, Ag and Al for the blue region and, more recently, the near-UV region.7,8 Longer midinfrared (mid-IR) wavelengths have also been approached by exploiting gold,910.11.12.–13 which in the IR range behaves as a very good conductor, with low penetration depths for the electromagnetic fields. Strictly speaking, however, the equivalent of a plasmonic metal in the mid-IR would possess carrier densities in the to range, something that can be achieved by heavily doping the semiconductor. Indeed, a few seminal works have already outlined the very interesting possibilities that will be opened by the use of such materials for mid-IR plasmonics.1415.–16 The idea of turning attention to semiconductors as “metals” in the mid-IR comes from the dependence of the plasma frequency (marking the onset of conducting behavior) on the carrier density , according to the relation , where represents the effective mass of the free carriers involved in the plasma oscillations. Another relevant issue when it comes to the use of plasmonic interfaces in optoelectronics and integrated devices is the compatibility with the existing Si photonics and CMOS platforms, something that cannot be solved with Au-based nanostructures. A natural choice in terms of semiconductor materials, from the point of view of integration, points toward Si and Ge.1718.–19 Between these two, Ge should be preferred both in standard mid-IR photonic devices, due to its inherently lower losses, and for plasmonic applications based on heavy doping, since the lower effective mass ( for Ge compared to for Si) allows a higher plasma frequency to be reached for a given doping level.
Material Growth and Characterization
We grow epitaxial Ge on standard Si wafers by low-energy plasma-enhanced chemical vapor deposition (LEPECVD).20,21 In an LEPECVD reactor, as sketched in Fig. 1(a), the wafer is exposed to a high intensity plasma, leading to growth rates of several nanometers per second through a very efficient decomposition of the reactive molecules. Since the plasma is obtained by a low-voltage arc discharge, the ion energies are in the range of tens of eV, low enough to allow the growth of crystalline materials. The plasma source is connected to a UHV chamber and the geometry of the plasma is designed by a grounded anode in the lower part of the growth chamber and by a magnetic field induced by a combination of coils and permanent magnets. The reactive gases, , , , and , are fed into the growth chamber through a gas dispersal ring placed above the anode. The dopant gases are diluted in Ar, respectively, 1% and 5%. The substrate is kept at a fixed potential with respect to ground and its temperature is adjusted between 200°C and 750°C by radiation heating. The deposition chamber has a base pressure of , while the working pressure is much higher, reaching . The growth rate is mainly controlled by the plasma density and by the gas flows and it is almost independent from the substrate temperature. For this reason, the growth rate and the surface diffusivity of the adatoms are completely decoupled and they can be optimized separately, a key issue in achieving a high concentration of activated dopants. Moreover, since the decomposition of the reactive molecules is dominated by the plasma, the surface chemistry between the substrate and the reactive molecules plays a modest role in the determination of the alloy composition, which can be easily controlled by the gas flows. The investigated samples were grown on p-type Si(001) substrates with a resistivity of 5 to . Before the heteroepitaxy, the native oxide was removed by dipping the substrate in aqueous hydrofluoric acid solution. All samples were deposited at 500°C at a growth rate of , with a flux of 20 sccm. The highest investigated doping () was achieved in situ by adding 0.15 sccm of .
The mid-IR response of materials with different levels of doping in the to range has been characterized by means of Fourier-transform infrared spectroscopy based on a Michelson interferometer, as sketched in Fig. 1(b). Figure 1(c) shows the reflectivity data acquired at near-normal incidence from each sample, after normalization to the reflectivity of a gold mirror. It can already be appreciated that the reflectivity drops from nearly 100% to about 35% when the plasma frequency of the material is crossed and the material’s behavior accordingly turns from metallic (at low frequencies) to dielectric (at high frequencies). In the dielectric region, clear Fabry–Pérot fringes appear because of the finite thickness of the Ge film (1 to for the different investigated samples). By applying a fitting procedure based on multilayer reflectivity and the Drude model, we extract the dielectric function from the experimental data, as demonstrated in Fig. 1(d). In agreement with the above discussion, it can be observed that the real part of the dielectric constant of each sample becomes negative below the corresponding plasma frequency, signifying metallic (plasmonic) behavior. To better highlight the plasmonic response of each material, we plot in Fig. 1(e) the energy loss function, calculated as , which peaks around the plasma frequency because of the energy loss channel opened by bulk plasmons in doped Ge. It can be discovered that the highest doping achieved in this series of samples () places the plasma frequency of Ge around (around wavelength), thus paving the road toward applications of this material platform in mid-IR plasmonics. Doping just above the level is technically achievable and would be sufficient to enable sensing throughout the whole of the important 8 to mid-IR window where many chemical and biological molecules have unique stretching and bending mode molecular absorption lines.
Example: Dielectric-Loaded Plasmonic Waveguides
As a representative example, we consider subdiffraction mode confinement below the dielectric cut-off in coupled metal-dielectric waveguides. In general, the strong reduction of the mode cross section in plasmonic waveguides, which is accompanied by a reduced effective wavelength as well, comes together with significantly increased losses, so that a trade-off between mode volume and propagation length always needs to be considered. For this reason, while standard dielectric waveguides are likely to be the preferred choice for on-chip transmission of signals over footprints that are much larger than the wavelength, plasmonic waveguides could be a choice when strong field confinement, even if only over small distances, is a premium feature, e.g., in integrated sensing applications. From this point of view, the use of a Ge-on-Si platform in the mid-IR allows for the realization of both low-loss dielectric waveguides, with intrinsic Ge already being proposed as one of the key materials for mid-IR waveguiding,19 and plasmonic waveguides, by exploiting heavy n-type doping with P, As, or Sb atoms.
Figure 2(a) shows representative data obtained by finite-difference frequency-domain methods22 of the quasidegenerate transverse-magnetic (TM) and transverse-electric (TE) fundamental modes supported by a square dielectric Ge waveguide on a Si substrate, as a function of the side of the waveguide. It can be observed, as expected, that the mode index decreases with the decreasing cross section of the waveguide, until it approaches the index of the substrate and cut-off is reached. For the wavelength used in these simulations, guided modes exist only for waveguide cross sections larger than about , with the mode being the last one to reach cut-off. A standard geometry for subdiffraction plasmonic waveguiding is the so-called dielectric-loaded waveguide,2324.–25 where a thin dielectric slab is placed on top of a plasmonic film. Figure 2(b) shows that, by exploiting this concept, a Ge dielectric waveguide with a cross section as small as on top of an n-doped Ge film can sustain a propagating plasmonic mode. The dielectric constant of the n-doped Ge is taken from experimental data for the doping level and the index of the supported plasmonic mode is about , confirming that the strong confinement is achieved at the expense of extremely large losses, as is common in most plasmonic waveguides. In perspective, more favorable waveguide geometries allowing for lower losses can be designed.
Heavily doped semiconductors might open a new era in mid-IR plasmonics due to the high quality of the material and the possibility of tuning the plasmonic response by controlling the carrier concentration with electrical or optical means. In this frame, the development of a group-IV plasmonic material platform would further benefit from the large integrability and low costs allowed by the compatibility with the Si photonics and CMOS platforms. The present materials already allow operation in the 10 to window, thus, e.g., covering part of the so-called fingerprint region which is of special interest for sensing applications. Future efforts along this road need to be focused on increasing the doping level of Ge and on understanding the sources of losses at mid-IR frequencies in order to optimize the plasmonic material and possibly enter the 5 to wavelength window.
The research leading to these results has received funding from the European Union’s Seventh Framework Programme under Grant Agreement No. 613055.
Paolo Biagioni is an associate professor in the Physics Department of Politecnico di Milano, Italy. He received his PhD degree in physics from the same institution in 2007 and was then a postdoctoral researcher at the University of Würzburg with a Von Humboldt fellowship. At present, his research interests include nano-optics and plasmonics, with special emphasis on mid-infrared group-IV plasmonics, linear and nonlinear properties of metal nanoantennas, and group-IV nanostructures working at the telecommunication wavelengths.
Jacopo Frigerio received his MA degree in physical engineering from Politecnico di Milano and his PhD degree cum laude in physics from Politecnico di Milano. During his PhD, he spent 2 months at the Instituté of Electronique Fondamentale (University Paris Sud) working on electro refraction in Ge quantum wells. His research interests include silicon photonics, thermoelectrics for energy harvesting, plasmonics for mid-infrared sensing applications, and integration of III-V on silicon.
Antonio Samarelli received his PhD degree in photonics at the University of Glasgow in 2010. From 2010 to 2014, he was a research associate with the School of Engineering in thermoelectric devices and silicon photonics. He is currently a research fellow for the School of Physics and Astronomy at the University of Glasgow. His current research interests include photonics in the near and mid infrared, plasmonics, MEMS, nanowire and nanofabrication of advanced systems.
Kevin Gallacher received his PhD degree from the University of Glasgow, Glasgow, UK, in 2014, on the fabrication and characterization of novel germanium on silicon photonic devices. At present, he is a research assistant at the School of Engineering at the University of Glasgow.
Leonetta Baldassarre is a researcher at the Center for Life and Nano Science of the Italian Institute of Technology (IIT) in Rome. She received her PhD degree in materials science in 2008. She was then employed at Universitaet Augsburg and at Elettra Sincrotrone Trieste. She received a national grant for the study of nanometer scale inhomogeneities in strongly correlated electron materials by tip-enhanced infrared spectroscopy.
Emilie Sakat received her PhD degree in physics from the Doctoral Graduate School of Polytechnique, France, currently she is a postdoctoral researcher at Politecnico di Milano in Italy. She specializes in plasmonics and nanophotonics for infrared devices. She received the best thesis award from the Airbus Group Foundation for her work on metal dielectric guided mode resonance structures and applications to filtering and infrared imaging.
Eugenio Calandrini graduated cum laude in physics at the Sapienza University of Rome in 2014 with a thesis on germanium mid-infrared plasmonics for sensing. Currently, he is enrolled as a PhD student in the Plasmon Technologies Department at the Italian Institute of Technology (IIT) in Genoa. He specializes in plasmonics and nanofabrication.
Ross W. Millar received his MEng degree in electronics and electrical engineering from the University of Glasgow in 2012. Currently, he is undertaking his PhD degree in the process-induced straining of germanium near-infrared devices.
Valeria Giliberti studied and graduated in physics at the University of Rome La Sapienza in 2011. From the same university, she received her PhD degree in materials science in 2014 for a thesis on nonlinear plasmonic effects in two-dimensional (2-D) electron gases. Currently, she is a postdoctoral researcher in the Physics Department of the University of Rome La Sapienza, where she works in the infrared spectroscopy group.
Giovanni Isella received his PhD degree in physics from the Politecnico di Milano, Italy, in 2001. Since 2001 he has been engaged in research on the integration of SiGe heterostructures on Si and their application to micro- and optoelectronics. He was appointed as assistant professor in 2003 and as associate professor in 2014 in the Physics Department at Politecnico di Milano.
Douglas J. Paul received his MA and PhD degrees in physics from the University of Cambridge. After spending 20 years in Cambridge, he moved to Glasgow University in 2007 to take up a professorial chair and is now director of the James Watt Nanofabrication Centre. He is fellow of the Royal Society of Edinburgh and the Institute of Physics, he won the President’s Medal in 2014. His research interests include nanoelectronics, SiGe technology, Si photonics, thermoelectrics, and quantum technology.
Michele Ortolani is an assistant professor in the Department of Physics, Sapienza University of Rome. He received his PhD degree in materials science in 2005. He was then employed at Elettra Sincrotrone Trieste, at Helmoltz Zentrum Berlin and at the Institute for Photonics and Nanotechnologies of the National Research Council of Italy (CNR-IFN). He received a national grant for the spectroscopic study of the terahertz electrodynamics of 2-D electrons in plasmonic microcavities. | <urn:uuid:7a2bf362-3840-4e2e-80ff-aa8353f00e42> | 2.921875 | 3,221 | Academic Writing | Science & Tech. | 29.951696 | 95,594,675 |
By James W. Anderson
Read Online or Download Hyperbolic Geometry (Springer Undergraduate Mathematics Series) PDF
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Found most commonly in these habitats: 20 times found in Low altitude rainforest, 7 times found in forest edge, mixed tropical forest, open area, 5 times found in rainforest, 2 times found in forest edge, open area, 3 times found in mixed tropical forest, 1 times found in miombo woodland, 1 times found in Sclerocarya - Bolusanthus Open Woodland (in Sekhukhune Mountain Bushveld).
Found most commonly in these microhabitats: 1 times ground forager(s), 1 times ex rotten log.
Collected most commonly using these methods: 22 times Malaise, 10 times Malaise trap, 2 times Malaise trap, 4 traps, 1 times Malaise, 3, 1 times Malaise, canopy trap, 1 times Hand collected.
Elevations: collected from 10 - 1550 meters, 734 meters average
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By: Jonathan A Campbell and William W Lamar
1032 pages, 1500 colour & 161 b/w photos, 109 b/w line drawings, maps, tables
Since the publication of The Venomous Reptiles of Latin America by Cornell UP in 1989, scientific discoveries and taxonomic changes have resulted in the addition of many taxa and species to the herpetology of the Western Hemisphere. This updated, heavily rewritten, and greatly expanded version of that book now includes accounts of all 192 species of venomous snakes and lizards found in the Western Hemisphere.
The 1500 colour photographs include many unique portraits of newly discovered species and fresh views of male, female, and juvenile individuals.
Volume I includes regional/country accounts with related bilingual identification keys and vegetation and topographic maps. Genus and species accounts treat all of the lizards, coralsnakes, and seasnakes. Volume II begins with the pitvipers, including all known species of rattlesnakes. This volume features four chapters by experts on mimicry, evolution, and snakebite treatment in tropical and temperate America. A glossary, literature-cited section and index serve both volumes.
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C programming specialist Alan Feuer covers major topics of C from different angles so the reader may gain a more complete understanding for the subject. You might wish to work this section after going through section F downlload pointers. Look for dangerous assumptions that you have made such as assuming that the data will always be positive, or that cc buffer is big enough, or that an array will always contain some data.
The puzzles are short exercises that stress the common building blocks that go into larger programs.
Frege’s Puzzle 1st Edition. This section is about null terminated strings. In many cases the programs are print statements, so the puzzle solution is the resulting printout. Some of the suggested solutions may have such problems.
The C Puzzle Book, Revised Edition – Ebook Detail
Once you have determined the puzzle solution, you may compare it with a detailed, step-by-step derivation offered in the pzuzle. A Bite of Magick download book Book: We does not store downloadd files on its server.
The C Puzzle Book puzsle intermediate C programming with an effective and unique method — and it’s fun! But when the program stops running, the window and all the program’s output vanishes. Searches related to ‘The C Puzzle Book, Revised Edition’ the c puzzle book pdf the c puzzle book pdf download the c puzzle book revised edition pdf the c puzzle book 1st edition pdf the c puzzle book free download the c puzzle the c puzzle book flipkart the c puzzle book ebook the c puzzle book ebook download the c puzzle book amazon.
He accomplishes this by including a variety of C program puzzles, challenging you to follow the puzzle through to determine the ;uzzle. Working through formidable puzzles and checking your results fine tunes your skills for future programming challenges.
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[PDF] The C Puzzle Book, Revised Edition – testkey ebooks search engine,Free ebooks download
The number of lines of code includes lines in the function body, not counting blank lines, braces, doucumentation, or lines contained in a previous answer. Two dimensional arrays are much less common than one dimensional arrays, downlad they can be useful. C and CPP Tags: Start at the beginning of the puzzles and solve them one-by-one in order.
In many cases the programs are pzuzle statements, so the puzzle solution is the resulting printout. If you merely read the puzzle and then look at the answer you are not using your time effectively. The C Puzzle Book is an excellent choice for all programmers who want to expand on their basic knowledge of the C programming language. Subscribe to this blog’s feed Powered by Typepad. To learn C, you need to write dozens of short programs so that the syntax rules and common strategies become second nature.
If you have a mostly working program, find ways in which it could fail, and then fix the problems. A puzzle rated [H-5] has only five lines of code, but those lines are hard to write.
Don’t rush through these. C programming specialist Alan Feuer covers major topics of C from different angles so the reader may gain a more complete ddownload for the subject.
Try to find them. The C Puzzle Book is an excellent choice for all programmers who want to expand on their basic knowledge of the C programming language. All of these puzzles are “console applications” which means that standard input is the keyboard and that standard output is the console on Windows machines, the “DOS Window”, sometimes called the “command prompt window”.
Kieran McKendrick has landed in the worse kind of hell Completely compliant with ANSI C, this book has downlad designed to help readers gain a more thorough understanding of the C syntax and semantics through interesting puzzles that challenge the readers’ proficiency with the basics.
To learn any subject, you need to practice it. This book is a great next step for any programmer who desires a deeper understanding of the C programming language. The Personality Puzzle Sixth Edition. John Nunn’s Chess Puzzle Book. Later in the day, or the next day, when ever you have some time available, do a few more.
Their purpose is to supplement a C textbook and to provide a way to review what you already know. Often students stop work as soon as they get their program sort of works. How to use the puzzles: | <urn:uuid:f6d9e252-d627-43be-80b0-c3e1a0f26c3c> | 2.984375 | 922 | Spam / Ads | Software Dev. | 55.340834 | 95,594,744 |
The “Island Bryophytes: Ecology and Diversity Group” includes one senior researcher, two Ph.D. students and a grant holder. Additional help is often provided by young researchers attracted to bryophytes and former M.Sc. and Ph.D. students. The research activities of the group focus on the study of Ecology and Diversity of Azorean bryophytes. Bryophytes (including mosses, liverworts and hornworts) are one of the most diverse and interesting taxonomic groups existing in the Azores. Due to their high dispersal ability, bryophytes have similar richness across the archipelagos of Azores, Madeira and the Canary Islands! Although the Azores represent only a small fraction of the European territory (0,02%!), the islands include about a quarter of all European species (25,5%), some of them included in the European Red List of Bryophytes. All these species are not only beautiful to behold [in the words of John H. Bland (1970): … strength is mingled with humility, gentleness and charm, with elemental essence, reflecting the gladness of wind, sun and rain.] but they are excellent ecological and physiological models, providing an original contribution to knowledge and science.
Four questions direct the ongoing research:
- How many species are there in the Azores? What is their distribution across the islands?
- What is the role of bryophytes on ecosystem services?
- Which species could be used as accurate indicators of global change (climatic & land-use)? and
- How to improve nature conservation strategies in order to preserve the biodiversity of bryophytes?
The IBED group works to improve the knowledge on:
Borges, P.A.V., Cardoso, P., Kreft, H., Whittaker, R.J., Fattorini, S., Emerson, B.C., Gil, A., Gillespie, R.G., Matthews, T.J., Santos, A.M.C., Steinbauer, M.J., Thébaud, C., Ah-Peng, C., Amorim, I.R., Aranda, S.C., Arroz, A.M., Azevedo, J.M., Boieiro, M., Borda-De-Água, L., Carvalho, J.C., Elias, R.B., Fernández-Palacios, J.M., Florencio, M., González-Mancebo, J.M., Heaney, L.R., Hortal, J., Kueffer, C., Lequette, B., Martín-Esquivel, J.L., López, H., Lamelas-López, L., Marcelino, J., Nunes, R., Oromí, P., Patiño, J., Pérez, A.J., Rego, C., Ribeiro, S.P., Rigal, F., Rodrigues, P., Rominger, A.J., Santos-Reis, M., Schaefer, H., Sérgio, C., Serrano, A.R.M., Sim-Sim, M., Stephenson, P.J., Soares, A.O., Strasberg, D., Vanderporten, A., Vieira, V. & Gabriel, R. (2018) A Global Island Monitoring Scheme (GIMS) for the long-term coordinated survey and monitoring of forest biota across islands.Biodiversity and Conservation, 27, 2567–2586. DOI:10.1007/s10531-018-1553-7 (IF2016 2,265; Q1 Biodiversity Conservation)
Patiño, J., Gómez-Rodriguez, C., Pupo-Correia, A., Sequeira, M. & Vanderpoorten, A. (2018) Trees as habitat islands: temporal variation in alpha and beta diversity in epiphytic laurel forest bryophyte communitiest.Journal of Biogeography, , 1-12. DOI:10.1111/jbi.13359 (IF2016 4,248; Q1 Ecology)
Boieiro, M., Matthews, T.J., Rego, C., Crespo, L., Aguiar, C.A.S., Cardoso, P., Rigal, F., Silva, I., Pereira, F., Borges, P.A.V. & Serrano, A.R.M. (2018) A comparative analysis of terrestrial arthropod assemblages from a relict forest unveils historical extinctions and colonization differences between two oceanic islands.PLOS One, 13(4), e0195492. DOI:10.1371/journal.pone.0195492 (IF2016 2,806; Q1 Multidisciplinary Sciences) | <urn:uuid:3821978d-367b-4a59-967b-41ecf3f305a9> | 2.90625 | 1,047 | About (Org.) | Science & Tech. | 72.004851 | 95,594,761 |
(Reuters) - The world is close to reaching tipping points that will make it irreversibly hotter, making this decade critical in efforts to contain global warming, scientists warned on Monday.
Scientific estimates differ but the world's temperature looks set to rise by six degrees Celsius by 2100 if greenhouse gas emissions are allowed to rise uncontrollably.
As emissions grow, scientists say the world is close to reaching thresholds beyond which the effects on the global climate will be irreversible, such as the melting of polar ice sheets and loss of rainforests.
"This is the critical decade. If we don't get the curves turned around this decade we will cross those lines," said Will Steffen, executive director of the Australian National University's climate change institute, speaking at a conference in London.
Despite this sense of urgency, a new global climate treaty forcing the world's biggest polluters, such as the United States and China, to curb emissions will only be agreed on by 2015 - to enter into force in 2020.
"We are on the cusp of some big changes," said Steffen. "We can ... cap temperature rise at two degrees, or cross the threshold beyond which the system shifts to a much hotter state."
For ice sheets - huge refrigerators that slow down the warming of the planet - the tipping point has probably already been passed, Steffen said. The West Antarctic ice sheet has shrunk over the last decade and the Greenland ice sheet has lost around 200 cubic km (48 cubic miles) a year since the 1990s.
Most climate estimates agree the Amazon rainforest will get drier as the planet warms. Mass tree deaths caused by drought have raised fears it is on the verge of a tipping point, when it will stop absorbing emissions and add to them instead.
Around 1.6 billion tonnes of carbon were lost in 2005 from the rainforest and 2.2 billion tonnes in 2010, which has undone about 10 years of carbon sink activity, Steffen said.
One of the most worrying and unknown thresholds is the Siberian permafrost, which stores frozen carbon in the soil away from the atmosphere.
"There is about 1,600 billion tonnes of carbon there - about twice the amount in the atmosphere today - and the northern high latitudes are experiencing the most severe temperature change of any part of the planet," he said.
In a worst case scenario, 30 to 63 billion tonnes of carbon a year could be released by 2040, rising to 232 to 380 billion tonnes by 2100. This compares to around 10 billion tonnes of CO2 released by fossil fuel use each year.
Increased CO2 in the atmosphere has also turned oceans more acidic as they absorb it. In the past 200 years, ocean acidification has happened at a speed not seen for around 60 million years, said Carol Turley at Plymouth Marine Laboratory.
This threatens coral reef development and could lead to the extinction of some species within decades, as well as to an increase in the number of predators.
As leading scientists, policy-makers and environment groups gathered at the "Planet Under Pressure" conference in London, opinions differed on what action to take this decade.
London School of Economics professor Anthony Giddens favours focusing on the fossil fuel industry, seeing as renewables only make up 1 percent of the global energy mix.
"We have enormous inertia within the world economy and should make much more effort to close down coal-fired power stations," he said.
Oil giant Royal Dutch Shell favours working on technologies leading to negative emissions in the long run, like carbon capture on biomass and in land use, said Jeremy Bentham, the firm's vice president of global business environment.
The conference runs through Thursday. | <urn:uuid:59453d59-829c-403c-84c8-15b4601ebd0b> | 3.515625 | 752 | News Article | Science & Tech. | 48.569487 | 95,594,762 |
New models of massive stellar eruptions hint at an extra layer of complexity when considering whether an exoplanet may be habitable or not. Models developed for our own Sun have now been applied to cool stars favoured by exoplanet hunters, in research presented by Dr Christina Kay, of the NASA Goddard Flight Center, on Monday 3rd July at the National Astronomy Meeting at the University of Hull.
Coronal mass ejections (CMEs) are huge explosions of plasma and magnetic field that routinely erupt from the Sun and other stars. They are a fundamental factor in so called "space weather", and are already known to potentially disrupt satellites and other electronic equipment on Earth.
However, scientists have shown that the effects of space weather may also have a significant impact on the potential habitability of planets around cool, low mass stars - a popular target in the search for Earth-like exoplanets.
Traditionally an exoplanet is considered "habitable" if its orbit corresponds to a temperature where liquid water can exist. Low mass stars are cooler, and therefore should have habitable zones much closer in to the star than in our own solar system, but their CMEs should be much stronger due to their enhanced magnetic fields.
When a CME impacts a planet, it compresses the planet's magnetosphere, a protective magnetic bubble shielding the planet. Extreme CMEs can exert enough pressure to shrink a magnetosphere so much that it exposes a planet's atmosphere, which can then be swept away from the planet. This could in turn leave the planetary surface and any potential developing lifeforms exposed to harmful X-rays from the nearby host star.
The team built on recent work done at Boston University, taking information about CMEs in our own solar system and applying it to a cool star system.
"We figured that the CMEs would be more powerful and more frequent than solar CMEs, but what was unexpected was where the CMEs ended up" said Christina Kay, who led the research during her PhD work.
The team modelled the trajectory of theoretical CMEs from the cool star V374 Pegasi and found that the strong magnetic fields of the star push most CMEs down to the Astrophysical Current Sheet (ACS), the surface corresponding to the minimum magnetic field strength at each distance, where they remain trapped.
"While these cool stars may be the most abundant, and seem to offer the best prospects for finding life elsewhere, we find that they can be a lot more dangerous to live around due to their CMEs" said Marc Kornbleuth, a graduate student involved in the project.
The results suggest that an exoplanet would need a magnetic field ten to several thousand times that of Earth's to shield their atmosphere from the cool star's CMEs. As many as five impacts a day could occur for planets near the ACS, but the rate decreases to one every other day for planets with an inclined orbit.
Merav Opher, who advised the work, commented, "This work is pioneering in the sense that we are just now starting to explore space weather effects on exoplanets, which will have to be taken into account when discussing the habitability of planets near very active stars."
Robert Massey | EurekAlert!
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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Metal oxynitrides as emerging materials with photocatalytic and electronic properties
- Scientific Highlights 14 September 2015 4733 hits
Mater. Horiz., 2015,2, 453-461
Oxynitrides of transition metals, alkaline earth metals and rare earth metals are intensively investigated as a group of materials to expand and tune the properties of oxides. The differences in polarizability, electronegativity and anion charge of nitrogen and oxygen induce changes in the physical and chemical properties of oxides by nitrogen introduction. The effects on properties arise from the higher covalency of the metal–nitrogen bond and the changes in the energies of electronic levels, and are important in slightly doped nitrogen metal oxides as in stoichiometric oxynitrides. More intense recent progress in oxynitride research has been made in some specific fields such as photocatalysis in water splitting and other processes as the observed small band gaps lead to activity in the visible light range. The stabilization of new perovskite oxynitrides, with the oxidation states of cations tuned by N/O stoichiometry, has led to new magnetic and dielectric materials. The lower electronegativity of nitrogen and larger crystal field splitting induced by N3− shifts the emission wavelengths of phosphors to the red, and oxynitridosilicates have been investigated as components of white LEDs.
Related Topics: Materials for energy and enviroment | <urn:uuid:64c7ea2f-e59e-47df-893b-823895c6e435> | 2.59375 | 305 | Academic Writing | Science & Tech. | 5.549764 | 95,594,796 |
Anisotropy sensitivity of an acoustic lens with slit aperture
Proceedings of the IEEE Ultrasonics Symposium
Publ by IEEE, Piscataway, NJ, United States
Please cite this item using this persistent URLhttp://hdl.handle.net/11693/27794
A conventional spherical acoustic lens is modified by restricting its aperture in the form of a slit to provide directional sensitivity. The spacing between the two parallel absorbing sheets forming the slit is adjustable to obtain varying slit widths. The resulting lens can be used in conjunction with V(Z) method to obtain leaky wave velocities of the sample under investigation as a function of direction. The theoretical V(Z) analysis of the lens involves a two-dimensional integral rather than one-dimensional integral of the conventional lens. Single crystal anisotropic materials are chosen as test samples. Reflection coefficients for anisotropic single crystals of given surface cut and orientation are calculated. Numerically evaluated V(Z) curves are used to deduce the surface wave velocity of the object for the given orientation. This is compared with the surface wave velocity directly calculated from the elastic parameters of the object. Results show the compromise between signal-to-noise ratio and angular resolution as the slit width is varied. V(Z) measurement results of a slitted lens are presented to be compared with calculated curves. The new lens is used to measure the acoustic velocity on the (001) surface of GaAs along varying directions with differing slit widths.
- Conference Paper
Showing items related by title, author, creator and subject.
Identification of damaged wheat kernels and cracked-shell hazelnuts with impact acoustics time-frequency patterns Ince, N.F.; Onaran I.; Pearson, T.C.; Tewfik, A.H.; Cetin, A.E.; Kalkan H.; Yardimci, Y. (2008)A new adaptive time-frequency (t-f) analysis and classification procedure is applied to impact acoustic signals for detecting hazelnuts with cracked shells and three types of damaged wheat kernels. Kernels were dropped ...
Oltulu O.; Mamedov A.M.; Ozbay E. (Springer Verlag, 2017)The vast majority of acoustic wave propagation in phononic band studies has been usually carried out by scattering inclusions embedded in a viscoelastic medium, such as air or water. In this study, we present calculated ...
Can G.; Akbas C.E.; Cetin A.E. (Institute of Electrical and Electronics Engineers Inc., 2016)This paper proposes a vessel recognition and classification system based on vessel acoustic signatures. Teager Energy Operator (TEO) based Mel Frequency Cepstral Coefficients (MFCC) are used for the first time in Underwater ... | <urn:uuid:8653a42e-064e-4b6d-99c1-9f61d024bcc1> | 2.640625 | 586 | Academic Writing | Science & Tech. | 39.05112 | 95,594,798 |
But a team of researchers has found that the opposite is the case on Australia's Great Barrier Reef.
Using 15 years of long-term monitoring data collected from 43 reefs by the Australian Institute of Marine Science (AIMS), the researchers from AIMS and the University of Adelaide have found that fish living on small, isolated reefs face a greater risk of local extinction.
The results have been published in Ecology, the journal of the Ecological Society of America.
"Our results support the idea that small and isolated reefs are more susceptible to local species extinctions because of the tendency for their fish populations to be more variable," says project leader Dr Camille Mellin, a Postdoctoral Fellow from AIMS and the University of Adelaide's Environment Institute.
"Isolated reefs receive relatively fewer ‘immigrant’ fish from adjacent reefs. If there is a disturbance to the population, such as a cyclone or coral bleaching, fish species on isolated reefs are much slower to recover. These populations are not as resilient to changes and are not easily replenished, increasing their probability of extinction."
By contrast, larger, more populated reefs see fewer large fluctuations in the fish population. This is partly due to the increased competition between species, and partly because of predators, which keep the population size in check.
"Our research suggests that conservation resources might be better allocated to the protection of large, connected habitats," Dr Mellin says.
As a result of the research, a map has been produced predicting the patterns of variability of coral reef fish species on the Great Barrier Reef.
"This new map is a potential new tool for the managers of the Great Barrier Reef Marine Park, but it’s important to emphasize that it is just one tool. When making management decisions for the Reef, a whole range of issues needs to be taken into account," Dr Mellin says.
Professor Corey Bradshaw, Director of Ecological Modeling at the University of Adelaide, says the research is "an essential piece in the marine planning puzzle". "If data for other reefs around the world become available, it would be possible to assess threats to species in those parts of the world using the same techniques," he says.
"Our research also demonstrates the need for long-term data sets," says Dr Julian Caley, Principal Research Scientist at AIMS. "This work would not have been possible without AIMS' commitment to the long-term monitoring of the Great Barrier Reef. This dataset is unique in the world and the only one that would have made this study possible."
The Great Barrier Reef is the world's largest reef system, composed of more than 2900 individual reefs and 900 islands stretching for more than 2600 kilometers (1600 miles).
Dr Camille Mellin | Newswise Science News
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
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Milky, turquoise-colored “dead zones,” some as large as the U.S. State of New Jersey, that are appearing repeatedly off the coast of southwest Africa, may be a sign of things to come for other areas of the coastlines of the eastern Atlantic and Pacific oceans. Toxic gas eruptions, bubbling up from the ocean floor, kill sea life, annoy human seaside residents, and may even intensify global warming. But the simple sardine may save the day, according to a study from the Pew Institute for Ocean Science.
In an article published in the November issue of Ecology Letters, authors Andrew Bakun and Scarla Weeks compare several areas around the world where strong offshore winds cause an upwelling of nutrients in the ocean and thus a population explosion of phytoplankton, the microscopic plant life that drifts through the ocean. Studying the waters off the coast of Namibia, the scientists found the resulting overproduction of phytoplankton died and sank to the bottom, and the decaying organic matter released copious amounts of methane and poisonous “rotten egg” smelling hydrogen sulfide gas.
As methane is 21 times more effective than carbon dioxide at trapping heat in the atmosphere, the resulting climate change may intensify this upwelling process and the possibility of even larger and more plentiful eruptions.
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
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Working under harsh Antarctic conditions, an international team of scientists, engineers and technicians has set in place the first critical elements of a massive neutrino telescope at the South Pole.
The successful deployment - in a 1.5 mile-deep hole drilled into the Antarctic ice - of a string of 60 optical detectors designed to sample phantom-like high-energy particles from deep space represents a key first step in the construction of the $272 million telescope known as IceCube.
The telescope and its construction are being financed by the National Science Foundation (NSF), which will provide $242 million. An additional $30 million in support will come from foreign partners. "Its all on track," according to Francis Halzen, a University of Wisconsin-Madison professor of physics and the principal investigator for the project. "This was our first exam. We met our milestones for the season and we can move on to the next Antarctic summer."
Francis Halzen | EurekAlert!
New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
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HTML title Tag
By Stephen Bucaro
The <title></title> tag defines the title of the webpage, which is displayed
in the title bar of the Web browser. The title tags must be located in the <head>
</head>section of the document. The contents of the title tag are also displayed
in the user's favorites. One of the most important functions of the title tag is in SEO
(Search Engine Optimization).
<title>Web Page Title</title>
Web Page Contents
Note: Don't confuse the title tag with the title attribute. The title
attribute is used in html elements to display text as a mouse-over tooltip popup.
Note: Your webpage's title should not include <, >, or & characters. Less-than
and greater than characters will cause an error on your webpage unless you replace
them with character codes. Even using character codes will cause problems because
some search engines ignore them. Don't use the ampersand character (&) because
it could be confused as defining a character code. Use the word and< instead.
One of the most important elements of SEO is the text within the title tags. The
contents of your title tag are displayed as the title in search engine results. For
highest page rank, your title should clearly explain what,s on the webpage. The
title should contain important keywords. Don,t put the same title on every webpage
of your website.
Every webpage must have a unique title. The name of your website or organization
should appear in the title tag of your home page, but should not be repeated in
other page titles. Your title should not be longer than 120 characters. Google
displays the title only up to the last complete word before the 66th character.
More HTML Code:
• HTML center Tag
• Line Break Basics
• The HTML BODY tag
• Image Map Basics
• Add an Image to a Web Page
• HTML Special Characters - Character Entities
• HTML5 Spinbox Control
• HTML Blockquote Basics
• Aligning an Image on Your Web Page
• HTML dfn Tag | <urn:uuid:f0894cd0-3b08-42ca-a05f-3485358343c9> | 2.71875 | 444 | Tutorial | Software Dev. | 54.372524 | 95,594,887 |
The radiation field at the centre of the Milky Way must be 1,000 times stronger than in the area surrounding our sun. Astrophysicists of the “Milky Way Galaxy” Collaborative Research Centre of Heidelberg University used computer simulations to reach this conclusion.
The calculations of the researchers from the Centre for Astronomy of Heidelberg University and the Max Planck Institute for Astronomy are based on the data from a type of “cosmic weather balloon” – the temperature data of an especially dense gas cloud near the centre of the Galaxy. Their research provides a new insight into the process of star formation, which is believed to take a different form at the centre of the Milky Way than it does at the Galaxy's edges.
The researchers characterise the centre of our home galaxy as an “inhospitable place”. The “weather conditions” there are reminiscent of those at stormy Cape Horn. While our more distal sun enjoys the conditions of the Galaxy's virtual Italian Riviera, a black hole and extremely hot or exploding stars create an intense “radiation wind” at the Galactic Centre. “In keeping with the metaphor, no one would ever build a ‘vacation home’ somewhere with such harsh conditions. Construction appears to be taking place nonetheless: there are gas clouds near the Galactic Centre where young stars appear to be forming,” says Dr. Paul Clark, a member of Prof. Dr. Ralf Klessen's team at the Centre for Astronomy of Heidelberg University (ZAH).
Dr. Clark and his colleagues studied an especially dense gas cloud called G0.253+0.016 more closely, and in spite of its proximity to the Galactic Centre, a large number of new stars have been observed to be forming there. Star formation is a tug of war between two forces, with gravity pulling interstellar gas inward and the internal pressure of the gas pushing outward. “Near the Galactic Centre, this gas is much hotter than at the edges of the Galaxy due to the strength of the radiation field, leading us to believe that star formation at the centre of the Milky Way differs from how we understand the process at its edges,” explains Dr. Clark.
To better understand the processes at the Galactic Centre, the “weather conditions” there – in this case the strength of the radiation field – need to be determined more precisely. So the researchers used G0.253+0.016 as a type of “cosmic weather balloon”. Astronomical observations were used to determine the temperature of the gas cloud. The data served as a basis for determining the temperature of G0.253+0.016 in relation to the radiation field. The Heidelberg astrophysicists varied the possible strength of this field until the result of the calculations matched the actual temperature measurements. The simulations took advantage of the Jülich-based “Milky Way” supercomputer that is used for projects of the Collaborative Research Centre.
The computer simulations indicated that the radiation field at the centre of the Milky Way must be 1,000 times stronger than in the area around our sun, which is located approx. 25,000 light years away at the Galaxy's edge. The Heidelberg astrophysicists believe that considerably less carbon monoxide (CO) is formed in the extreme conditions in the gas cloud. "Carbon monoxide plays a key role in most star-forming regions, as it helps to regulate the cloud temperatures. The lower CO content in the Galactic Centre clouds will have strong implications for their evolution,“ continues Dr. Clark. Further studies of the “cosmic weather balloon” should provide a complete picture of the star formation process at the centre of the Milky Way.
The results of the research were published in “The Astrophysical Journal Letters”. In addition to Dr. Clark and Prof. Klessen, the research team included Dr. Simon Glover and Dr. Rahul Shetty, as well as Dr. Sarah Ragan from the Heidelberg Max Planck Institute for Astronomy.Internet information:
Contact:Dr. Paul Clark
Marietta Fuhrmann-Koch | idw
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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It is hard to know what is going on over 3000 km beneath our feet, but until recently scientists were fairly confident that they understood the way the iron atoms in the Earth’s core packed together. However, new research has overturned conventional thinking and revealed that the structure of the core is not as straightforward as was once thought.
Pressures and temperatures at the Earth’s core are stupendous – more than 3.5 Mbar and 7000K – and currently it is impossible to recreate these conditions in the laboratory. Our information about the core comes from observing the way that seismic waves travel through the core, extrapolating from experimental studies and studying iron rich meteorites.
As a result we know that the core is mostly iron, but that it also must contain some light impurities such as oxygen, silicon, sulphur, hydrogen and magnesium (because the density of the core is too low to be pure iron). The most significant impurity is thought to be nickel, which makes up between 5 and 15% of the composition.
Most studies on the Earth’s core have approximated the composition to be pure iron. “It was assumed that the alloy elements were not very important for the structural and elastic properties of the core,” says Igor Abrikosov, a theoretical physicist at Linköping University in Sweden.
Experimental and theoretical studies on pure iron led to a ‘standard model’ for the core, which said that the iron atoms were packed in a ‘hexagonal close packed’ formation. This resembles a honeycomb structure in which the atoms are in densely packed layers of hexagons, with every other layer lying directly above its partner two layers below.
Other packing structures were ruled out because they were assumed to be less energetically efficient. “At moderate pressures other structures have some magnetism and they turn out to have lower stability,” explains Abrikosov.
Carrying out experiments at anything close to the pressures and temperatures experienced at the core is pretty much impossible. “To achieve high pressures the sample has to be made very small and then it is difficult to see the diffraction patterns from the structures,” explains Leonid Dubrovinsky, a geo-scientist at the University of Bayreuth in Germany. What is more, at high temperatures the iron tends to diffuse and react with the carbon in the diamond anvil cell – a device that pinches samples between two diamond points and creates extreme pressures.
An inability to recreate core conditions hampered our understanding of the core, but in recent years powerful computer models have stepped in the breach. “Expertise has been developed in ‘Ab intio’ (first principles) calculations and we are able to do higher quality extrapolations to understand core conditions,” says Abrikosov.
In addition experiments have improved greatly, with very high pressures and temperatures reached recently in new diamond anvil cells. Combined with the use of synchrotron radiation scientists have been able to observe structures at conditions that are ever closer to conditions at the Earth’s outer core.
Using this combination of theory, experiments and powerful simulations Abrikosov, Dubrovinsky and their colleagues have revisited the core. This time they have also included alloy elements such as Nickel and Magnesium in their calculations and, to their surprise, they found that it has a significant effect.
“At high pressures the magnetism is squeezed out of the other structures and they all have similar stability,” says Abrikosov, who presented his findings at the 1st EuroMinScI Conference near Nice, France in March this year. The new research has revealed that ‘face centred cubic’ and ‘body centred cubic’ structures can not be ruled out and that all of these structures are energetically possible. “The standard model has been killed,” says Abrikosov.
EuroMinScI is the European Collaborative Research (EUROCORES) Programme on “European Mineral Science Initiative” developed by the European Science Foundation (ESF).
Face centred cubic structures have an atom in the centre of every face, as well as at each of the corners, while body centred cubic has one atom in the centre of the cube. Compared to the hexagonal close packed the face centred cubic structure alternates every third layer, with the atoms making a spiral pattern up through the layers.
Elements like nickel, silicon, oxygen and magnesium are also likely to play a key part in way atoms pack in the core. Recent experiments have shown that at very high pressures magnesium atoms are compressed to such an extent that they can fit easily into iron structures. In addition the element nickel is more comfortable than iron in a ‘face centred cubic’ structure.
So why does this matter and what kind of difference could these structures make in the core" “It has implications for the anisotropy of the core,” says Dubrovinsky.
Studies of seismic waves have revealed that the waves travel faster in a north-south direction and slower in an east-west direction through the core – a phenomenon that scientists call anisotropic. The way the atoms pack in the core is vital for understanding this anisotropy.
What is more, the Earth’s core produces our magnetic field. Without it the Earth would be bombarded with dangerous cosmic rays and life would struggle to survive. As well as relying on Earth’s magnetic field to protect us, we now use it to navigate and keep satellites in place. Life on Earth depends upon the magnetic field, but until we understand the core we can’t fully understand how this field is created, or how it is likely to change.
For scientists studying the Earth’s core it is time to go back to the drawing board and rethink what lies underneath our feet. However, a new generation of powerful computer simulations, along with experiments that we could previously only dream about, mean that optimism is high and scientists are confident that the core will reveal its secrets soon.
Source: European Science Foundation
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Radioactive sulfur isotopes; Stable sulfur isotopes
Sulfur. A chemical element that is one of the constituents of living organisms and of the Earth.
Isotopes. Isotopes are different nuclear forms of the same element. For a given element, a constant number of protons but different numbers of neutrons in the nucleus correspond to different isotopes. Sulfur of standard atomic mass 32.065 u has 18 isotopes, most of which are not stable and undergo radioactive decay.
Stable sulfur isotopes. Stable isotopes are isotopes that do not decay within an experimentally observable time frame. Stable isotopes have essentially the same chemical characteristics and, therefore, their behavior is chemically almost identical. The different masses lead to isotope fractionation in chemical, physical, and especially biological reactions. Four stable isotopes occur in nature: 32S (95.02%), 33S (0.75%), 34S (4.21%), and 36S (0.02%) (Hoefs, 2008). Typically, the ratio of the two most...
KeywordsSulfate Reduction Hydrogen Sulfide Sulfur Isotope Iron Sulfide Sulfur Cycle
- Amend, J. P., Edwards, K. J., and Lyons, T. W. (eds.), 2004. Sulfur Biogeochemistry - Past and Present. Boulder: Geological Society of America.Google Scholar
- Böttcher, M. E., and Piel, C., 2008. Kinetic S-34/S-32 fractionation during degassing and hydroxylation of hydrogen sulfide, and protonation of bisulfide. Geophysical Research Abstracts, 10, 232.Google Scholar
- Canfield, D. E., 2001. Biogeochemistry of sulfur isotopes. In Valley, J. W., and Cole, D. R. (eds.), Reviews in Mineralogy and Geochemistry, The Mineralogical Society of America, 607.Google Scholar
- Clark, I. D., and Fritz, P., 1997. Environmental Isotopes in Hydrogeology. Boca Raton: Lewis.Google Scholar
- Hoefs, J., 2008. Stable Isotope Geochemistry, 6th edn. Berlin: Springer.Google Scholar | <urn:uuid:eb73b3b1-60d4-4593-844e-cd0b073c0c29> | 3.546875 | 477 | Academic Writing | Science & Tech. | 45.302404 | 95,594,952 |
2 Astrophysics and Cosmology Chapter 33Astrophysics and Cosmology
3 Units of Chapter 33 Stars and Galaxies Stellar Evolution: The Birth and Death of StarsDistance MeasurementsGeneral Relativity: Gravity and the Curvature of SpaceThe Expanding Universe: Redshift and Hubble’s LawThe Big Bang and the Cosmic Microwave Background
4 Units of Chapter 33The Standard Cosmological Model: the Early History of the UniverseDark Matter and Dark EnergyLarge-Scale Structure of the UniverseFinally…
5 33.1 Stars and GalaxiesThe universe is vast; we define new units to make distances easier to measure.A light-year (ly) is the distance light travels in a year:The most distant planet, Pluto, is about 6 x 10-4 ly from us. The next nearest star is 4.3 ly away.
6 33.1 Stars and GalaxiesOn a dark moonless night, a band of stars can be seen traversing the sky. Ancients called it the Milky Way; we now know that it is our view of our galaxy.
7 33.1 Stars and GalaxiesWe still call our galaxy the Milky Way; it is a spiral galaxy, disc-shaped with spiral arms.It is about 100,000 ly in diameter and about 2000 ly thick, and contains some 100 billion stars.
8 33.1 Stars and GalaxiesThese two drawings show what our galaxy would look like from the outside; the photograph was taken in the infrared.
9 33.1 Stars and GalaxiesMany faint cloudy patches can be seen in the sky, some with the naked eye and some with simple telescopes. They are of several types:Star clusters – large groups of stars within our galaxyNebulae – glowing clouds of gas and dustGalaxies – other than our own, at varying distances from us
10 33.1 Stars and GalaxiesThe next nearest galaxy, Andromeda, is some 2 million light-years away.It is estimated that there are about as many galaxies in the universe as there are stars in our own galaxy – 100 billion or so.Many galaxies occur in gravitationally bound clusters, some of which have only a few galaxies and others of which have thousands.
11 33.1 Stars and GalaxiesThis table gives some idea of the vast distances between objects in the universe.
12 33.2 Stellar Evolution: the Birth and Death of Stars The absolute luminosity, L, of a star is the power it radiates, in watts.The apparent brightness, l, is the power per unit area at the Earth, a distance d away.They are related:(33-1)
13 33.2 Stellar Evolution: the Birth and Death of Stars More massive stars are also more luminous.The surface temperature of a star can be measured from its spectrum; surface temperatures range from about 3500 K to 50,000 K.
14 33.2 Stellar Evolution: the Birth and Death of Stars An especially useful way of comparing stars is the Hertzsprung-Russell (H-R) diagram, which plots absolute luminosity vs. temperature.
15 33.2 Stellar Evolution: the Birth and Death of Stars Most stars fall along the main sequence line in the H-R diagram. There are also some outliers:Red giants, with low temperature and high luminosityWhite dwarfs, with high temperature and low luminosity
16 33.2 Stellar Evolution: the Birth and Death of Stars Stellar evolution cannot be observed directly, but can be inferred from observations of stars at different points in their lifetimes:Star formation begins when interstellar cloud of gas and dust begins to contractAs it contracts, mass collects in the center and begins to heat upWhen the core is hot enough, about 107 K, hydrogen fusion begins
17 33.2 Stellar Evolution: the Birth and Death of Stars For a sun-like star, time from beginning to stable fusion is about 30 million years; stable fusion (during which star is on Main Sequence) continues for about 10 billion yearsEventually core is mostly helium; outer layers of star once again begin to collapse and heat
18 33.2 Stellar Evolution: the Birth and Death of Stars Eventually, next layer of hydrogen becomes hot enough for fusion
19 33.2 Stellar Evolution: the Birth and Death of Stars Hotter still and the helium can fuse to carbon; this is as far as a Sun-like star gets.Carbon core again collapses and heats; outer layers of star expand and are ejectedStar is now a white dwarfMore massive stars will fuse elements up to iron, then collapse in a supernova to a neutron star or black hole
20 33.2 Stellar Evolution: the Birth and Death of Stars This shows the evolutionary track of a Sun-like star after it leaves the Main Sequence (where it has stayed at essentially the same point)
21 33.2 Stellar Evolution: the Birth and Death of Stars Novae and supernovae are violent eruptions; besides the massive-star supernova, a nova or supernova can occur in a binary star system.This example would result in a nova; if there were a neutron star instead of the white dwarf it would be a supernova:
22 33.3 Distance Measurements In order to plot stars on an H-R diagram, their distances must be known. Different techniques are used at different distances:Parallax is the apparent motion of a star against a background of more distant stars during the course of a yearThe apparent shift is measured, and then the distance determined geometrically
23 33.3 Distance Measurements This diagram illustrates how parallax works
24 33.3 Distance Measurements Parallax works out to 100 ly; beyond that the shift is too smallH-R diagram can be used to determine absolute luminosity and therefore distanceCertain variable stars have a luminosity that is proportional to their periodType Ia supernovae all have about the same luminosityRedshift, due to expansion of the universe, is used at the longest distances
25 33.4 General Relativity: Gravity and the Curvature of Space Principle of equivalence: it is impossible to distinguish a uniform gravitational field and a uniform accelerationAnother way to put it: mass in Newton’s first law is the same as the mass in the universal law of gravitation
26 33.4 General Relativity: Gravity and the Curvature of Space A light beam will be bent either by a gravitational field or by acceleration
27 33.4 General Relativity: Gravity and the Curvature of Space This can make stars appear to move when we view them past a massive object
28 33.4 General Relativity: Gravity and the Curvature of Space Einstein’s general theory of relativity says that space itself is curved – hard to visualize in three dimensions!This is a two-dimensional space with positive curvature:
29 33.4 General Relativity: Gravity and the Curvature of Space This two-dimensional space has negative curvature:
30 33.4 General Relativity: Gravity and the Curvature of Space We do not know if the universe overall has positive, negative, or zero curvature; current evidence is that the curvature is very close to zero.
31 33.4 General Relativity: Gravity and the Curvature of Space Space is curved around massive objects:
32 33.4 General Relativity: Gravity and the Curvature of Space In the extreme limit, a black hole is formed – the curvature is so strong that even light cannot escape if it gets too close.“Too close” means inside the Schwarzschild radius:
33 33.5 The Expanding Universe: Redshift and Hubble’s Law The expansion of the universe was proposed to explain the correlation between distance and recessional velocity for distant galaxies.The recessional velocity causes spectra to be shifted to longer wavelengths, due to the Doppler effect:(33-3)
34 33.5 The Expanding Universe: Redshift and Hubble’s Law These plots illustrate the effects of a redshift. The parameter z measures the redshift:(33-4)
35 33.5 The Expanding Universe: Redshift and Hubble’s Law Hubble’s law relates the recessional velocity to the distance:(33-6)The constant H is called the Hubble constant, and is measured experimentally.
36 33.5 The Expanding Universe: Redshift and Hubble’s Law If all galaxies are moving away from us, are we at the center of the expansion?No – think of the surface of an expanding balloon. Every point on the surface is moving away from every other point; there is no center.The age of the universe can be calculated by the Hubble constant:
37 33.6 The Big Bang and the Cosmic Microwave Background Projecting universal expansion backwards – universe must have been very tiny at the beginningBig Bang – not an explosion, but an expansion of spacetime itselfCosmic microwave background radiation – comes from every direction, has spectrum of black-body radiation with a temperature of K
38 33.6 The Big Bang and the Cosmic Microwave Background This background radiation has been mapped in great detail, and is very strong evidence in support of the Big Bang.
39 33.7 The Standard Cosmological Model: the Early History of the Universe This is the outline of the beginning of the universe, as we currently understand it:
40 33.7 The Standard Cosmological Model: the Early History of the Universe Before s, all four forces were unified, in a way we don’t understandGrand unified era – no distinction between quarks and leptonsAround s the strong force separates from the othersHadron era – lepton-quark soup at first, the quarks become confinedInflation?
41 33.7 The Standard Cosmological Model: the Early History of the Universe Around 10-6 s most hadrons have disappeared; once average kinetic energy dropped below nucleon mass, nucleon creation stopped, leaving a slight excess of matter over antimatterOnce the kinetic energy was below the pion mass, no more hadrons could be formedThis happened around 10-4 s, beginning the lepton era
42 33.7 The Standard Cosmological Model: the Early History of the Universe After about 10 s electron-positron pairs could no longer be formedThis begins the radiation era; universe consists mostly of photons and neutrinos, and is opaqueAt about 3 minutes, nuclear fusion begins, creating deuterium, helium, and some lithiumAfter about 380,000 years the photons decouple from matter – the universe is now transparent
43 33.7 The Standard Cosmological Model: the Early History of the Universe The cosmic background radiation is these photons, cooled through further expansionAt 200 million years, stars begin to formGalaxies begin to form around 1 billion years
44 33.8 Dark Matter and Dark Energy What is the ultimate fate of the universe?It depends on whether the universe is closed, flat, or open
45 33.8 Dark Matter and Dark Energy Critical density is the density where the universe is flat:The properties of the cosmic microwave background radiation suggest that the universe is flat.However – only 4% of the needed density can come from ordinary matter.
46 33.8 Dark Matter and Dark Energy It has been known for some time, by studying galactic rotation curves and gravitational lensing, that more matter must be present than can be seen. This dark matter is now thought to make up about 23% of the total density.
47 33.8 Dark Matter and Dark Energy Just recently, astronomers were surprised to discover that the expansion of the universe is accelerating. This cannot be explained by any known force.What is causing the acceleration is not known; generically this is referred to as dark energy.
48 33.8 Dark Matter and Dark Energy This dark energy is found to contribute 73% to the density, bringing it to the critical density.To summarize, the universe’s mass-energy comes from:Dark energy, 73%Matter, 27%, which is23% dark matter4% ordinary matter
49 33.9 Large-Scale Structure of the Universe Small inhomogeneities in the cosmic microwave background are thought to be related to large-scale structure in the clustering of galaxies. This distribution of 50,000 galaxies displays clear evidence of structure:
50 Summary of Chapter 33Milky Way is our galaxy; disc-shaped, contains 100 billion starsAstronomical distances are measured in light-yearsStars begin as collapsing dust clouds; they contract and heatHydrogen fusion begins; some heavier elements are formedStar is stable - on Main Sequence
51 Summary of Chapter 33When core is exhausted, star expands and cools while core contracts and heatsSolar-mass star becomes white dwarfMore massive stars explode as supernovae, leaving neutron star or black hole behindEquivalence principle – gravitational field and acceleration are indistinguishableGravity is a curvature of spacetimeDistant galaxies are redshifted, due to Doppler effect of recession velocity
52 Summary of Chapter 33Universe is expanding, and is about 13.7 billion years oldCreated in Big BangCosmic microwave background radiation is remnant of Big BangStandard Big Bang model has universe beginning as very hot and dense; as it expands it cools, and various reactions cease to occurHydrogen, deuterium, helium, and a tiny amount of lithium are created as universe cools
53 Summary of Chapter 33Once atoms could form, stars and galaxies became possibleMust be more than visible matter to account for observed motions – dark matterExpansion of universe is accelerating – dark energyDark energy, dark matter, and ordinary matter combine to give universe critical density | <urn:uuid:faa8914b-c54f-45d9-9c85-cc7507899eee> | 3.78125 | 2,821 | Truncated | Science & Tech. | 40.269102 | 95,594,953 |
Ocean acidification (OA) is spreading rapidly in the western Arctic Ocean in both area and depth, according to new interdisciplinary research reported in Nature Climate Change by a team of international collaborators, including University of Delaware professor Wei-Jun Cai.
The research shows that, between the 1990s and 2010, acidified waters expanded northward approximately 300 nautical miles from the Chukchi slope off the coast of northwestern Alaska to just below the North Pole. Also, the depth of acidified waters was found to have increased, from approximately 325 feet to over 800 feet (or from 100 to 250 meters).
Over the last decade, the Chinese National Arctic Research Expedition (CHINARE) and US collaborators have studied the environmental and climate changes of the western Arctic Ocean and has witnessed rapid expansion of the 'acidified' water in the upper water column. This photo shows the science team working on an ice station in front of the icebreaker XueLong during the summer 2010 cruise in the northern Canada Basin, very close to the North Pole.
Credit: Zhongyong Gao and Di Qi
"The Arctic Ocean is the first ocean where we see such a rapid and large-scale increase in acidification, at least twice as fast as that observed in the Pacific or Atlantic oceans," said Cai, the U.S. lead principal investigator on the project and Mary A.S. Lighthipe Professor of Earth, Ocean, and Environment at UD.
"The rapid spread of ocean acidification in the western Arctic has implications for marine life, particularly clams, mussels and tiny sea snails that may have difficulty building or maintaining their shells in increasingly acidified waters," said Richard Feely, NOAA senior scientist and a co-author of the research. Sea snails called pteropods are part of the Arctic food web and important to the diet of salmon and herring. Their decline could affect the larger marine ecosystem.
Among the Arctic species potentially at risk from ocean acidification are subsistence fisheries of shrimp and varieties of salmon and crab.
Other collaborators on the international project include Liqi Chen, the Chinese lead principal investigator and scientist with the Third Institute of Oceanography of State Oceanic Administration of China; and scientists at Xiamen University, China and the University of Gothenburg, Sweden, among other institutions.
Pacific Winter Water
The researchers studied water samples taken during cruises by Chinese ice breaker XueLong (meaning "snow dragon") in summer 2008 and 2010 from the upper ocean of the Arctic's marginal seas to the basins as far north as 88 degrees latitude, just below the North Pole, as well as data from three other cruises.
Scientists measured dissolved inorganic carbon and alkalinity which allows them to calculate pH and the saturation state for aragonite, a carbonate mineral that marine organisms need to build their shells.
Data collected by ship and model simulations suggest that increased Pacific Winter Water (PWW), driven by circulation patterns and retreating sea ice in the summer season, is primarily responsible for this OA expansion, according to Di Qi, the paper's lead author and a doctoral student of Chen.
"This work will help increase our understanding of climate change, carbon cycling, and ocean acidification in the Arctic, particularly as it affects marine and fishery science and technology," said Chen.
PWW comes from the Pacific Ocean through the Bering Strait and shelf of the Chukchi Sea and into the Arctic basin. In recent years, melting sea ice has allowed more of the Pacific water to flow through the Bering Strait into the Arctic Ocean. Pacific Ocean water is already high in carbon dioxide and has higher acidity. As the ocean mass moves north, it absorbs additional carbon dioxide from decomposing organic matter in the water and sediments, increasing acidity.
The melting and retreating of Arctic sea ice in the summer months also has allowed PWW to move further north than in the past when currents pushed it westward toward the Canadian archipelago.
Arctic ocean ice melt in the summer, once found only in shallow waters of depths less than 650 feet or 200 meters, now spreads further into the Arctic Ocean.
"It's like a melting pond floating on the Arctic Ocean. It's a thin water mass that exchanges carbon dioxide rapidly with the atmosphere above, causing carbon dioxide and acidity to increase in the meltwater on top of the seawater," said Cai. "When the ice forms in winter, acidified waters below the ice become dense and sink down into the water column, spreading into deeper waters."
Peter Bothum | EurekAlert!
New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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July 17, 2018
The Radio Optical Reference Frame
Work at the United States Naval
Observatory (USNO) in cooperation with the Remote Sensing Division of the
Naval Research Laboratory
(NRL), has led to the establishment of an astrometric quasi-inertial
radio reference frame. This reference frame is based on the radio
positions of strong extragalactic radio sources such as quasars and
radio galaxies and has been made possible by the stability of the
positions of these sources. However, most extragalactic sources
display spatial structure on milli-arcsecond scales for
the strong radio emission associated with their compact cores.
Despite this shortcoming the positions of a large number of these
sources can be used to define a quasi-inertial reference frame (i.e. a
frame whose basis is inertial). Higher accuracies can theoretically be
obtained by taking into account the structure of the sources.
The radio positions of the over 400 extragalactic sources
comprising the RORF are as uniformly distributed over the entire sky
as possible with available observations. The positional accuracy of the
final catalog is at the 0.5 milli-arcsecond level. The final
orientation of the catalog has been obtained by a (rigid body)
rotation of the positions into the system of the International Earth
Rotation Service (1992 IERS Standards), and is consistent with the FK5
J2000.0 optical system, within the limits of the link accuracy.
Observations used to determine radio source positions are made
using the technique of Very Long Baseline Interferometry (VLBI). An
``observation'' basically consists of the difference in the time of
arrival of the radio signals from a distant source measured by pairs
of radio telescopes. These telescopes can be separated by distances
up to the diameter of the Earth and can measure time of arrival
differences with accuracies on the order of 10 picoseconds.
Observations made over a time period of approximately 15 years using
radio telescopes located around the world have been combined in a
general solution to solve for the positions of the RORF.
This is an Official U.S. Navy Web Site | <urn:uuid:e60a5f7b-b7f5-4323-9c38-e08cee04898f> | 3.203125 | 476 | Knowledge Article | Science & Tech. | 26.513158 | 95,594,971 |
TeachMeFinance.com - explain Rankine cycle
Rankine cycle --
The thermodynamic cycle that is an ideal standard for comparing performance of heat-engines, steam power plants, steam turbines, and heat pump systems that use a condensable vapor as the working fluid. Efficiency is measured as work done divided by sensible heat supplied.
About the author
Copyright © 2005 by Mark McCracken, All Rights Reserved. TeachMeFinance.com is an informational website, and should not be used as a substitute for professional medical, legal or financial advice. Information presented at TeachMeFinance.com is provided on an "AS-IS" basis. Please read the disclaimer for details. | <urn:uuid:74bd16d0-45f3-4828-81e8-5f5ab477f400> | 2.890625 | 143 | Knowledge Article | Science & Tech. | 33.125222 | 95,595,021 |
SCRIBE Enables Distributed Genomically Encoded Memory
MIT engineers have transformed the genome of the bacterium E. coli into a long-term storage device for memory. SCRIBE (Synthetic Cellular Recorders Integrating Biological Events ) is a scalable platform that uses genomic DNA for analog, rewritable, and flexible memory distributed across living cell populations. They envision that this stable, erasable, and easy-to-retrieve memory will be well suited for applications such as sensors for environmental and medical monitoring.
“You can store very long-term information,” says Timothy Lu, an associate professor of electrical engineering and computer science and biological engineering. “You could imagine having this system in a bacterium that lives in your gut, or environmental bacteria. You could put this out for days or months, and then come back later and see what happened at a quantitative level.”The new strategy, described in the Nov. 13, 2014 issue of the journal Science ("Genomically encoded analog memory with precise in vivo DNA writing in living cell populations"), overcomes several limitations of existing methods for storing memory in bacterial genomes, says Lu, the paper’s senior author. Those methods require a large number of genetic regulatory elements, limiting the amount of information that can be stored.The earlier efforts are also limited to digital memory, meaning that they can record only all-or-nothing memories, such as whether a particular event occurred. Lu and graduate student Fahim Farzadfard, the paper’s lead author, set out to create a system for storing analog memory, which can reveal how much exposure there was, or how long it lasted. To achieve that, they designed a “genomic tape recorder” that lets researchers write new information into any bacterial DNA sequence.
The researchers showed that SCRIBE enables the recording of arbitrary transcriptional inputs into DNA storage registers in living cells by translating regulatory signals into ssDNAs. In E. coli, they expressed ssDNAs from engineered retrons that use a reverse transcriptase protein to produce hybrid RNA-ssDNA molecules. These intracellularly expressed ssDNAs are targeted into specific genomic loci where they are recombined and converted into permanent memory. The team could show that genomically stored information can be readily reprogrammed by changing the ssDNA template and controlled via both chemical and light inputs. This demonstrates that genomically encoded memory can be read with a variety of techniques, including reporter genes, functional assays, and high-throughput DNA sequencing.
SCRIBE enables the recording of analog information such as the magnitude and time span of exposure to an input. This convenient feature is facilitated by the intermediate recombination rate of our current system (~10–4 recombination events per generation), which we validated via a mathematical model and computer simulations. For example, the scientists stored the overall exposure time to chemical inducers in the DNA memory of bacterial populations for 12 days (~120 generations), independently of the induction pattern. The frequency of mutants in these populations was linearly related to the total exposure time.
The idea that DNA could be used to store information is an idea that is long familiar to sf readers. Fantasy writer Barbara Hambly uses a similar idea in her 1982 Darwath trilogy. She describes how wizards succeeded in tying information to the DNA of selected individuals.
In the story, several people from 1980's California find themselves transported across the Void to another planet and the Realm of Darwath. They face a deadly species of queerly magical beings - the Dark - who destroyed civilization thousands of years ago. Everything that was made of paper (like books and records) were burned to stave off attacks by the Dark. Tying memories to a few suitable bloodlines was the only way to preserve a record of that period that would endure.
Update 15-Apr-2017: See the Heritable Memories Bloodline from The Time of the Dark (1982) by Barbara Hambly. End update.
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is devoted to the creative science inventions and ideas of sf authors. Look for
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' It was a ... coffin, form-fitted to Nessus himself...'
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'The car surged and lifted, clearing its top by a negligible margin.'
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Science fiction authors are serious about sleep, too.
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Art imitates life imitates art.
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Griffith University academics are challenging the foundations of quantum science with a radical new theory based on the existence of, and interactions between, parallel universes.
In a paper published in the prestigious journal Physical Review X, Professor Howard Wiseman and Dr Michael Hall from Griffith's Centre for Quantum Dynamics, and Dr Dirk-Andre Deckert from the University of California, take interacting parallel worlds out of the realm of science fiction and into that of hard science.
The team proposes that parallel universes really exist, and that they interact. That is, rather than evolving independently, nearby worlds influence one another by a subtle force of repulsion. They show that such an interaction could explain everything that is bizarre about quantum mechanics
Quantum theory is needed to explain how the universe works at the microscopic scale, and is believed to apply to all matter. But it is notoriously difficult to fathom, exhibiting weird phenomena which seem to violate the laws of cause and effect.
As the eminent American theoretical physicist Richard Feynman once noted: "I think I can safely say that nobody understands quantum mechanics."
However, the "Many-Interacting Worlds" approach developed at Griffith University provides a new and daring perspective on this baffling field.
"The idea of parallel universes in quantum mechanics has been around since 1957," says Professor Wiseman.
"In the well-known "Many-Worlds Interpretation", each universe branches into a bunch of new universes every time a quantum measurement is made. All possibilities are therefore realised – in some universes the dinosaur-killing asteroid missed Earth. In others, Australia was colonised by the Portuguese.
"But critics question the reality of these other universes, since they do not influence our universe at all. On this score, our "Many Interacting Worlds" approach is completely different, as its name implies."
Professor Wiseman and his colleagues propose that:
- The universe we experience is just one of a gigantic number of worlds. Some are almost identical to ours while most are very different;
- All of these worlds are equally real, exist continuously through time, and possess precisely defined properties;
- All quantum phenomena arise from a universal force of repulsion between 'nearby' (i.e. similar) worlds which tends to make them more dissimilar.
Dr Hall says the "Many-Interacting Worlds" theory may even create the extraordinary possibility of testing for the existence of other worlds.
"The beauty of our approach is that if there is just one world our theory reduces to Newtonian mechanics, while if there is a gigantic number of worlds it reproduces quantum mechanics," he says.
"In between it predicts something new that is neither Newton's theory nor quantum theory.
"We also believe that, in providing a new mental picture of quantum effects, it will be useful in planning experiments to test and exploit quantum phenomena."
The ability to approximate quantum evolution using a finite number of worlds could have significant ramifications in molecular dynamics, which is important for understanding chemical reactions and the action of drugs.
Professor Bill Poirier, Distinguished Professor of Chemistry at Texas Tech University, has observed: "These are great ideas, not only conceptually, but also with regard to the new numerical breakthroughs they are almost certain to engender."
Explore further: When parallel worlds collide, quantum mechanics is born
Physical Review X, journals.aps.org/prx/abstract/ … 03/PhysRevX.4.041013 | <urn:uuid:7f273c67-f548-46f4-9100-3a7bc5e1679b> | 2.890625 | 706 | News Article | Science & Tech. | 26.461806 | 95,595,055 |
Running large-scale computer simulations of conditions of the thick layer between the Neptune's atmosphere and core, known as the mantle, researchers have helped solve the mystery of what lies beneath the most distant planet in our solar system.
Frozen mixtures of water, ammonia and methane make up the planet's mantle, but the form in which these chemicals are stored is poorly understood.
The study, published in the journal Proceedings of the National Academy of Sciences, showed that frozen mixtures of water and ammonia inside Neptune - and other ice giants, including Uranus - are likely to form a little-studied compound called ammonia hemihydrate.
"This study helps us better predict what is inside icy planets like Neptune. Our findings suggest that ammonia hemihydrate could be an important component of the mantle in ice giants, and will help improve our understanding of these frozen worlds," said Andreas Hermann from University of Edinburgh in Britain.
Extremely low temperatures on planets like Neptune - called ice giants - mean that chemicals on these distant worlds exist in a frozen state, the researchers said.
Using laboratory experiments to study these conditions is difficult, as it is very hard to recreate the extreme pressures and temperatures found on ice giants.
So the scientists ran large-scale computer simulations of conditions in the mantle and by looking at how the chemicals there react with each other at very high pressures and low temperatures, they were able to predict which compounds are formed in the mantle.
The work was carried out in collaboration with scientists at Jilin University, China.
"Computer models are a great tool to study these extreme places, and we are now building on this study to get an even more complete picture of what goes on there," Hermann said. | <urn:uuid:dcacda72-e9be-439d-95cd-102efb4a34d9> | 4.03125 | 352 | Truncated | Science & Tech. | 23.620531 | 95,595,057 |
A theorized but never-before detected property of quantum matter has now been spotted in the lab, a team of scientists reports.
The team proved that a particular quantum material can demonstrate electrical dipole fluctuations — irregular oscillations of tiny charged poles on the material — even in extremely cold conditions, in the neighborhood of minus 450 degrees Fahrenheit.
The material, first synthesized 20 years ago, is called k-(BEDT-TTF)2Hg(SCN)2 Br. It is derived from organic compounds, but behaves like a metal.
“What we found with this particular quantum material is that, even at super-cold temperatures, electrical dipoles are still present and fluctuate according to the laws of quantum mechanics,” said Natalia Drichko, associate research professor in physics at the Johns Hopkins University.
“Usually, we think of quantum mechanics as a theory of small things, like atoms, but here we observe that the whole crystal is behaving quantum-mechanically,” said Drichko, senior author of a paper on the research published in the journal Science.
Classical physics describes most of the behavior of physical objects we see and experience in everyday life. In classical physics, objects freeze at extremely low temperatures, Drichko said. In quantum physics — science that has grown up primarily to describe the behavior of matter and energy at the atomic level and smaller — there is motion even at those frigid temperatures, Drichko said.
“That’s one of the major differences between classical and quantum physics that condensed matter physicists are exploring,” she said.
An electrical dipole is a pair of equal but oppositely charged poles separated by some distance. Such dipoles can, for instance, allow a hair to “stick” to a comb through the exchange of static electricity: Tiny dipoles form on the edge of the comb and the edge of the hair.
Drichko’s research team observed the new extreme-low-temperature electrical state of the quantum matter in Drichko’s Raman spectroscopy lab, where the key work was done by graduate student Nora Hassan. Team members shined focused light on a small crystal of the material. Employing techniques from other disciplines, including chemistry and biology, they found proof of the dipole fluctuations.
The study was possible because of the team’s home-built, custom-engineered spectrometer, which increased the sensitivity of the measurements 100 times.
The unique quantum effect the team found could potentially be used in quantum computing, a type of computing in which information is captured and stored in ways that take advantage of the quantum states of matter. | <urn:uuid:8b8087b7-6c22-4337-9820-88e9e48d6e56> | 3.5 | 555 | News Article | Science & Tech. | 28.666936 | 95,595,069 |
Smaller Is Faster
Smaller Is Faster
I have always thought this principle in terms of computer hardware. Just a while ago, I started to think this principle is also applicable to software development.
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“Smaller is faster” is a hardware design principle as you might already know it. Generally speaking, smaller pieces of hardware will be faster than larger pieces. I have always thought this principle in terms of computer hardware. Just a while ago, I started to think this principle is also applicable to software development. Throughout this post, I’ll try to give some insights and supporting examples for “smaller is faster” in software development.
Understanding a piece of code is an everyday activity for every programmer. It’s hard to focus when the code gets big. We have been trying to overcome code complexity by single responsibility principle and many others. Typically, we are trying to minimize or in other words make the code smaller so that we can understand it faster. A function or method with 100 lines of code would be scary to anyone. Hence, the smaller a piece of code, the faster you can understand it.
The team size can be one of the key factors for a successful software project. As team size grows, human communication complexities become a burden to the project. Adding more programmers to a project can make a project even worse than it was. In my experience, I have always experienced that smaller teams produce faster. I think it isn’t just communication. As the team gets bigger, you also need to deal with politics. In a team of three people, you can’t really have politics. Consequently, the smaller the team size is, the faster you develop.
In contemporary software development, microservices architecture has been widely adopted. Previously, we have been developing monolith applications where a single code base that contains all of an application’s logic. As the project grows bigger, it’s almost impossible to reason about the code base or manage each piece of software. So, decomposing project into smaller parts became the natural solution. Therefore, the smaller service you have, the faster it is to develop, test and deploy it.
All in all, “smaller is faster” is applicable to various aspects of software development. The smaller the software is, the faster it becomes to understand, develop, deploy, and optimize it.
Published at DZone with permission of Yusuf Aytaş , DZone MVB. See the original article here.
Opinions expressed by DZone contributors are their own. | <urn:uuid:fc7013ae-50d7-4c07-a969-267f40132d76> | 2.875 | 577 | Truncated | Software Dev. | 43.325289 | 95,595,078 |
Rank the vector combinations on the basis of their angle, measured counterclockwise from the positive x axis. Vectors parallel to the positive x axis have an angle of 0 degrees. All angle measures fall between 0 and 360 degrees.
Rank from largest to smallest. To rank items as equivalent, overlap them.
(F+C) , (D), (A+E), (A+C), (A+D), (A+B)
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The satellite was renamed ‘Hinode’ which is Japanese for Sunrise, which is most appropriate since Hinode will watch at close hand massively explosive solar flares erupting from the Sun’s surface and rising into interstellar space.
Hinode has three instruments: the Solar Optical Telescope (SOT), the X-Ray Telescope (XRT), and the EUV Imaging Spectrometer (EIS) which has been led by University College London’s Mullard Space Science Laboratory (MSSL).
“Waiting for the first data from an instrument that has taken years to design and build is always a heart-stopping moment,” said Prof Len Culhane, EIS Principal Investigator, “We create incredibly sensitive detectors such as EIS, then strap them to a rocket and hurl them into space under extremely challenging conditions. Finding out that it survived and is working correctly is a huge relief because the options are very limited if it is not.”
Each sensitive instrument has successfully survived launch, opened its protective door and taken its first test pictures of the Sun. They are now being prepared to take scientific data over the coming months and will reveal a great deal about Coronal Mass Ejections – violent explosions on the Sun that can hurl plasma at the Earth itself with serious consequences for communications networks and satellites.
“The first pictures from Hinode show us that our satellite is in great condition,” said Prof Louise Harra, EIS Project Scientist who will shortly take over the Principal Investigator role, “The images from the Solar Optical Telescope are already showing a huge improvement over those from past missions such as Yohkoh and will help us understand the Sun in new detail. The EIS instrument will watch movements in the Sun’s atmosphere in unprecedented detail, allowing us to observe the build up to a Coronal Mass Ejection and eventually even predict them.”
In addition to working on Hinode, UK solar scientists are also part of the NASA STEREO mission, which successfully launched two satellites on 26th October 2006. See http://www.pparc.ac.uk/Nw/Stereo_launch.asp for details.
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
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Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
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Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
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Just in case I forget, Dan’s activity on factoring trinomials by creating a headache – it’s a good one that I’ve used a couple of times and seems to spark enough interest.
Jon Orr’s introduction of factoring is a bit different, but may still have some helpful content?
Not that it’s every really pi day in Australia, but in case I want to run some activities sometime…
- I can just eat circular food and measure things to discover pi like I did with my college class once
- I could have them write pi poetry
Here are some links to resources / puzzles / activities etc. that I have found useful doing work on congruent triangles.
- Multiple lesson plans to follow including some activities on proofs
- Picture puzzle to use for cutting shapes into two congruent shapes
- Also something from Fawn I haven’t tried yet here.
The Pac-man activity was a great resource to work through when I did it once with 7 Supp – not only for thought provoking start to the concepts but to re-visit later on as well.
Another lesson with understanding reflections as their goal is from Dane’s sight here.
Varied names around the world for the same topic! A key starting point in looking at this though is probably Michael Fenton’s blog on the topic, in particular noting the way he talks about the indices as ‘number of factors of’. This idea is talked about further here on Sara’s site where she also includes some other ideas worth looking at. I found the factors idea particularly helpful when discussing fractional indices (it was one of three ways I looked at it – the other of the two ways I think students found helpful was just recognising, for example, how 9^1/2 x 9^1/2 = 9, therefore 9^1/2 must be 3). | <urn:uuid:2c42449d-c2a4-43d6-9e56-325220c508d9> | 3.578125 | 402 | Personal Blog | Science & Tech. | 50.961364 | 95,595,120 |
Language Reference |
Used to perform a logical conjunction on two expressions.
result = expression1 && expression2
The && operator syntax has these parts:
Part Description result Any variable. expression1 Any expression. expression2 Any expression.
If, and only if, both expressions evaluate to True, result is True. If either expression evaluates to False, result is False.
For information on when a run-time error is generated by the && operator, see the Operator Behavior table.
JScript uses the following rules for converting non-Boolean values to Boolean values:
- All objects are considered true.
- Strings are considered false if and only if they are empty.
- null and undefined are considered false.
- Numbers are false if and only if they are zero.
© 1997 by Microsoft Corporation. All rights reserved.
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<A HREF="http://techref.massmind.org/techref/inet/iis/jscript/htm/js623.htm"> && Operator</A>
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Welcome to massmind.org!
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刚接触 PHP ，其中有两个打印（输出函数），即 echo() 和 print()，咋看起来很像。于是乎，在网上查询了一下，以下是来自官方的 Q&A:
What is the difference between echo and print?
1. Speed. There is a difference between the two, but speed-wise it should be irrelevant which one you use.
echo is marginally faster since it doesn't set a return value if you really want to get down to the nitty gritty.
2. Expression. print() behaves like a function in that you can do:
$ret = print "Hello World"; And $ret will be 1. That means that print
can be used as part of a more complex expression where echo cannot. An
example from the PHP Manual:
$b ? print "true" : print "false";
print is also part of the precedence table which it needs to be if it
to be used within a complex expression. It is just about at the bottom
of the precedence list though. Only "," AND, OR and XOR are lower.
3. Parameter(s). The grammar is: echo expression [, expression[,
expression] ... ] But echo ( expression, expression ) is not valid.
This would be valid: echo ("howdy"),("partner"); the same as: echo
"howdy","partner"; (Putting the brackets in that simple example
no purpose since there is no operator precedence issue with a single
term like that.)
So, echo without parentheses can take multiple parameters, which get
echo "and a ", 1, 2, 3; // comma-separated without parentheses
echo ("and a 123"); // just one parameter with parentheses
print() can only take one parameter:
print ("and a 123");
print "and a 123";
posted @ 2009-02-23 16:26
Tiger 阅读(204) | 评论 (0)
| 编辑 收藏
在 linux 命令汗下执行 PHP 脚本：php [options] [-f] <file> [--] [args...]
php -f hello_world.php
more info please type "php --help" or "man php"
posted @ 2009-02-23 10:44
Tiger 阅读(2645) | 评论 (0)
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|Black and white picture of a Histioteuthis heteropsis Cock-eyed or Strawberry Squid, at the Monterey Bay Aquarium, June 27, 2014|
(Berry, 1913 )
Calliteuthis heteropsis (Berry, 1913 )
Histioteuthis heteropsis, the Cock-eyed Squid, also known as the Strawberry Squid, is a species of cock-eyed squid. These squid are named for their peculiar set of differently sized eyes, one being small and blue and the other being large and yellowish. It is thought that the large eye is used to spy for food and predators in the down-welling light above the squid, while the smaller eye peers into the darkness below, seeking out bio-luminescent signals.
- "We have a new visitor from the deep in our Tentacles special exhibition: the cock-eyed squid!". MBA Tumblr. Monterey Bay Aquarium. June 27, 2014. Retrieved March 29, 2016.
- "Histioteuthis heteropsis". Tree of Life. Treeoflife web project. Retrieved 27 June 2014.
- Belman, Bruce W (1978). "Respiration and the effects of pressure on the mesopelagic vertically migrating squid Histioteuthis heteropsis". Limnology and Oceanography. 23 (4): 735–9. doi:10.4319/lo.1978.23.4.0735.
|This squid-related article is a stub. You can help Wikipedia by expanding it.| | <urn:uuid:b6ff7ab7-3a5d-4613-9569-5cf219af93e3> | 2.984375 | 315 | Knowledge Article | Science & Tech. | 66.161077 | 95,595,207 |
32. When a beam of white light passes perpendicularly through a flat pane of glass, it is not dispersed into a spectrum. Why not?
35. Light of what color is scattered most of atmosphere? Least?
36. If the earth had no atmosphere, what would the color of the sky be during the day?
39. Radio waves are able to diffract readily around buildings, as anybody with a portable radio receiver can verify. However, light waves, which are also electromagnetic waves, undergo no discernible diffraction around the buildings. Why not?
40. Conduct the following experiments.
? Conduct "A Scattering Experiment"
We can verify the origin of the blue sky by adding a few drops of milk to a glass of water and then shining light from a flashlight through the mixture. If we look at the glass from the side, perpendicular to light beam, the light scattered by the milk droplets will appear blue. If we look at the glass opposite the flashing towards the beam, it will have an orange tint.
Place a pencil in a clear glass of water so that a portion of it is in the water and a portion of it is out of the water. Look at the pencil from different angles and describe what you see.
? Use a CD or DVD and a strong light source (like a flashlight or a fairly focused lamp, but NOT a laser pointer) and shine the light on the surface of the disk at an angle and then view it from the other side. Adjust the position of item and the lighting in the room and see if you can see anything going on.
Post to the discussion below your findings to each of the experiments
42. When you look at your reflection in the inside, concave side of a spoon, your image appears upside down. Why? Discuss how your distance from the spoon and the degree of curvature of the spoon affects your image.© BrainMass Inc. brainmass.com July 19, 2018, 12:15 am ad1c9bdddf
Discussions on the basic questions on various phenomenon in ray and wave optics with diagrams. | <urn:uuid:494db165-8bbb-42c4-a7ff-2f1140718e94> | 3.6875 | 431 | Q&A Forum | Science & Tech. | 70.188735 | 95,595,217 |
You could be looking right at the secret to the universe when you gaze skyward this summer. Now, if only your eyes were as powerful as a 570-megapixel camera. In April, scientists with the Dark Energy Survey, led by Josh Frieman at Fermi National Accelerator Laboratory in Batavia, released their first major results, two years into the ongoing five-year project aimed at unraveling the evolution of the cosmos. They’re using a supersized camera—the world’s most powerful—to snap photos from Earth of deep space. We’re talking eight-billion-light-years-away-deep.
The map they created based on the images shows clumps of dark matter, which also happen to be where scientists believe galaxies were most likely to have formed. The long-term goal of the team, which includes more than 300 scientists from around the world, is to understand why the universe is expanding at an ever-faster rate.
They’re reconstructing eight billion years’ worth of the history of the universe (which is thought to be nearly 14 billion years old) through these snapshots. “That will give us a first, real indication of what dark energy is about,” Frieman says. The team will keep taking pictures for the next three years, and the resulting images will let them test their theories on how the universe has evolved to this point—and where we’re going, literally, as the Milky Way hurtles ever farther through the universe.
The $40 million camera built at Fermilab is mounted on a massive telescope in Chile, in part because it isn’t very windy there. “Stars twinkle because of turbulence,” says Frieman. “If you take a picture through turbulence, the star would be fuzzed out.”
Because these galaxies are so far away, the snapshots require long exposures. For each spot in the sky, the camera takes 10 pictures over five years, each time leaving the shutter open for 90 seconds. Researchers analyze the composite image to see where the light wiggles—a sign that dark matter is present and bending the light with its gravitational pull.
This map, based on measurements created from the composite photos, accounts for about two million galaxies. The dark red represents regions packed with galaxies and, therefore, a lot of dark matter. “It’s analogous to a terrain map,” Frieman says. “Blue is like valleys, where there’s less stuff.”
For more photos, visit darkenergysurvey.org.
3 months ago | <urn:uuid:4a1c79bd-0ab1-4561-a5e7-8d444943df38> | 3.515625 | 545 | News Article | Science & Tech. | 51.69976 | 95,595,231 |
Mountain minerals erode into the seas. Duh!
On their way to the seas; these minerals make dirt. Duh!
Organisms in the dirt convert these minerals into living soil. Duh!
Plant health depends on these soil minerals. Duh!
Animal health depends on plant health. Duh!
All nutrients are composed of natural minerals. Duh!
Virtually all of the minerals that plants consume have been solubilized from the soil. Duh!
Plant and animal health depends on these minerals remaining in (or being returned to) a given area for as long as possible. Duh!
To maintain optimum soil, plant and animal health, they must remain in a given area long enough to be replaced by more minerals eroding from the mountains. Duh!
Or we must artificially replace them in each area. Duh!
Minerals that are solubilized move toward the seas more quickly than these same minerals in an insoluble state. Duh!
Mountain rocks erode quite slowly. This is why we have phrases like: "steady as a rock". Duh!
People "harvest" the plant and animal products that depend on these minerals. Duh!
Then people transport these products away from where they were grown. Duh!
This depletes the essential mineral nutrients, from the areas where these products were grown. Duh!
The taste of food is very dependent on the nutrients in that food. Duh!
Most food does not taste nearly as good as it did forty years ago. Duh!
Let me repeat what I said earlier; all soluble minerals get transported, in food, away from the areas where they are essential to the health of the soil, plants and animal that depend on the solubilized minerals in these areas. Duh!
Ultimately, they get flushed, with our sewage, into the seas or transported with toxic "waste" to a landfill. Duh!
Science continues to make new discoveries. Duh!
At some point, science will discover new essential mineral nutrients. Duh!
Major new scientific discoveries often take decades to become accepted by mainstream science. Duh!
"640K ought to be enough for anybody"
Bill Gates 1981
"I think there is a world market for maybe 5 computers"
Thomas Watson Chairman IBM 1943
"Everything that can be invented, has been invented"
Charles H. Duell, Director of U.S. Patent Office 1899
"Who the hell wants to hear actors talk?"
Harry M Warner, Warner Brothers Pictures, 1927
"There is no likelihood man can ever tap the power of the atom"
Robert Miliken, Nobel Prize Physics, 1923
"Heavier than air flying machines are impossible"
Lord Kelvin, President of the Royal Society, 1895
Max Planck wrote about this:
"A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it."
Truth never triumphs — its opponents just die out.
Science advances one funeral at a time. | <urn:uuid:1c563a2b-588c-41b6-9de6-b0d70d5787f1> | 2.75 | 661 | Audio Transcript | Science & Tech. | 60.060332 | 95,595,233 |
The Azooxanthellate Scleractinia (Coelenterata: Anthozoa) of Australia
CitationSouthwestern Pacific Ocean Biogeographic Information System (OBIS) Node. The Azooxanthellate Scleractinia (Coelenterata: Anthozoa) of Australia. Occurrence dataset https://doi.org/10.15468/jsoxjm accessed via GBIF.org on 2018-07-20.
DescriptionA total of 237 species of azooxanthellate Scleractinia are reported for the Australian region, including seamounts off the eastern coast. This study was based on approximately 5500 previously unreported specimens collected from 500 localities, as well as a re-examination of most of the types and previously reported specimens from the Australian region. Compared to all azooxanthellate species, those from Australia have a slightly higher percentage of species that are solitary and unattached (or transversely dividing), due to a disproportionate number of species in the families Flabellidae and Turbinoliidae. Bathymetrically they are typical of the worldwide fauna. Sixty-seven species are endemic to the Australian region. Azooxanthellate corals comprise half of the species and genera of the order Scleractinia (Cairns, 1999b), and, with the publication of this paper, consist of 703 species. Two hundred thirty-seven species, or one-third, of the azooxanthellate species occur off Australia, making it one of the richest regions in the world for this type of coral. The purpose of this paper was not to re-describe the azooxanthellate coral fauna of Australia, as most of the species have been adequately described and figured within the last 15 years in papers about the Australian fauna or adjacent regions (Cairns, 1989a, 1994, 1995, 1998, 1999a; Cairns & Parker, 1992; Cairns & Zibrowius, 1997). Instead, the primary purpose is to document and verify all previously published records of the 237 Australian azooxanthellate species in the form of annotated synonymies, to augment these reports with additional records from the various Australian museums, and to list deposition of types and type localities for all species. This exhaustive compilation then provides the basis for a meaningful zoogeographic analysis of this fauna, the second goal of the paper.
technical point of contact | <urn:uuid:807a4cca-1c65-476a-9435-89ccc02ddea4> | 3.171875 | 517 | Academic Writing | Science & Tech. | 21.806534 | 95,595,237 |
The myth of “substantial equivalence” between GMOs and non-crops (called “isolines”) takes yet another hard science hit.
A team of researchers in Mexico City has published their of genetic data on rice, canola, maize, sunflower, and pumpkin. They looked at wild, , and non- cultivated varieties of these five crops, analyzing phenotypic change.
The reported here on Hygeia.of a crop is defined by a set of characteristics expressed by the crop’s genetic code (DNA). In theory, genetically engineered plants will show phenotypic changes only linked to the targeted scientists added to the and hope to express. For example, a corn plant engineered to express the toxin should not be different from normal corn in other ways, as has been
However, genetics are complicated and unintended consequences often occur. Of the five crops analyzed in this study, maize, pumpkin and rice showed the most variation betweenand non- cultivars. These three crops demonstrated wide variation for related to days to flowering, number of seeds/fruit, plant height, and pollen viability. In fact, the researchers report that for non- and cultivars of maize, pumpkin and rice, “almost all analyzed differ statistically.”
This latest report of “unintended consequences” from the genetic engineering process again raises questions about the official concerns about GMOs elsewhere on Hygeia.policy claiming that other that GMOs are “substantial equivalent” or “functionally equivalent” to the original, non- isoline. We report on this and other
Alejandra Hernández-Terán, Ana Wegier, Mariana Benítez, Rafael Lira, and Anna E. Esclaante, “Domesticated, Genetically Engineered, and Wild Plant Relatives Exhibit Unintended Phenotypic Differences: A Comparative Plant Science, December 5, 2017. Profiling Rice, Canola, Maize, Sunflower, and Pumpkin,” | <urn:uuid:e7299a54-445a-4573-9bbf-4250a57e9ff4> | 3.25 | 421 | Truncated | Science & Tech. | 22.401387 | 95,595,246 |
It's almost a rite of passage in physics and astronomy. Scientists spend years scrounging up money to build a fantastic new instrument. Then, when the long-awaited device finally approaches completion, the panic begins: How will they handle the torrent of data?
That's the situation now, at least, with the Square Kilometer Array (SKA), a radio telescope planned for Africa and Australia that will have an unprecedented ability to deliver data -- lots of data points, with lots of details -- on the location and properties of stars, galaxies and giant clouds of hydrogen gas.
In a study published in The Astronomical Journal, a team of scientists at the University of Wisconsin-Madison has developed a new, faster approach to analyzing all that data.
Hydrogen clouds may seem less flashy than other radio telescope targets, like exploding galaxies. But hydrogen is fundamental to understanding the cosmos, as it is the most common substance in existence and also the "stuff" of stars and galaxies.
As astronomers get ready for SKA, which is expected to be fully operational in the mid-2020s, "there are all these discussions about what we are going to do with the data," says Robert Lindner, who performed the research as a postdoctoral fellow in astronomy and now works as a data scientist in the private sector. "We don't have enough servers to store the data. We don't even have enough electricity to power the servers. And nobody has a clear idea how to process this tidal wave of data so we can make sense out of it."
Lindner worked in the lab of Associate Professor Snezana Stanimirovic, who studies how hydrogen clouds form and morph into stars, in turn shaping the evolution of galaxies like our own Milky Way.
In many respects, the hydrogen data from SKA will resemble the vastly slower stream coming from existing radio telescopes. The smallest unit, or pixel, will store every bit of information about all hydrogen directly behind a tiny square in the sky. At first, it is not clear if that pixel registers one cloud of hydrogen or many -- but answering that question is the basis for knowing the actual location of all that hydrogen.
People are visually oriented and talented in making this interpretation, but interpreting each pixel requires 20 to 30 minutes of concentration using the best existing models and software. So, Lindner asks, how will astronomers interpret hydrogen data from the millions of pixels that SKA will spew? "SKA is so much more sensitive than today's radio telescopes, and so we are making it impossible to do what we have done in the past."
In the new study, Lindner and colleagues present a computational approach that solves the hydrogen location problem with just a second of computer time.
For the study, UW-Madison postdoctoral fellow Carlos Vera-Ciro helped write software that could be trained to interpret the "how many clouds behind the pixel?" problem. The software ran on a high-capacity computer network at UW-Madison called HTCondor. And "graduate student Claire Murray was our 'human,'" Lindner says. "She provided the hand-analysis for comparison."
Those comparisons showed that as the new system swallows SKA's data deluge, it will be accurate enough to replace manual processing.
Ultimately, the goal is to explore the formation of stars and galaxies, Lindner says. "We're trying to understand the initial conditions of star formation -- how, where, when do they start? How do you know a star is going to form here and not there?"
To calculate the overall evolution of the universe, cosmologists rely on crude estimates of initial conditions, Lindner says. By correlating data on hydrogen clouds in the Milky Way with ongoing star formation, data from the new radio telescopes will support real numbers that can be entered into the cosmological models.
"We are looking at the Milky Way, because that's what we can study in the greatest detail," Lindner says, "but when astronomers study extremely distant parts of the universe, they need to assume certain things about gas and star formation, and the Milky Way is the only place we can get good numbers on that."
With automated data processing, "suddenly we are not time-limited," Lindner says. "Let's take the whole survey from SKA. Even if each pixel is not quite as precise, maybe, as a human calculation, we can do a thousand or a million times more pixels, and so that averages out in our favor."
Robert Lindner | EurekAlert!
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences | <urn:uuid:bdbcc84f-cdde-4f4e-b13b-e318d53ad4e4> | 3.625 | 1,497 | Content Listing | Science & Tech. | 41.647376 | 95,595,261 |
New space race begins: Astronomers compete to build next generation of 'super-telescopes' to reveal the hidden universe
- Huge observatories will be built on top of mountains in Hawaii and Chile
- These include the Giant Magellan Telescope, the Thirty Meter Telescope and the European Extremely Large Telescope
- Astronomers hope to use these super-telescopes to look at the first stars
- They also plan to uncover life-threatening asteroids heading towards the planet and spot Earth-like worlds
A new space race is heating that could help unravel some of the biggest mysteries of the universe.
Astronomers around the world are going head to head to develop three major telescopes that will be at least 10 times more powerful than anything in operation today.
The race will see sophisticated observatories built on top of mountains in Hawaii and Chile in an attempt to see the wonders hiding in the outer reaches of the cosmos.
Scroll down for video...
The race will see sophisticated observatories built on top of mountains in Hawaii and Chile in an attempt to see the wonders hiding in the outer reaches of the cosmos
In contention are the Giant Magellan Telescope, the Thirty Meter Telescope and the European Extremely Large Telescope.
Astronomers hope to use these super-telescopes to look at the first stars and galaxies that formed after the Big Bang 13.7 billion years ago.
They also plan to uncover life-threatening asteroids heading towards the planet and spot Earth-like and potentially habitable worlds in orbit around other stars.
The Giant Magellan Telescope is currently under construction atop Las Campanas Peak in Chile at an altitude of 8,366 ft (2,550 metres) above sea level. Pictured is an artist's impression of what it will look like
An artist's impression of the European Extremely Large Telescope on Cerro Armazones, a 3,060-metre mountaintop in Chile's Atacama Desert: For comparison, look at the size of the cars
THE BILLION DOLLAR CONTENDERS
Giant Magellan Telescope
Location: Campanas Peak in Chile
Cost: $700 million (£420 million)
Status: To be completed within 10 years
Funding: U.S, Korea and Australia
The Thirty Meter Telescope
Location: Mauna Kea's peak in Hawaii
Cost: €1bn (£900m)
Status: To be completed around 2022
Funding: Caltech, University of California (UC) and the Association of Canadian Universities for Research in Astronomy (ACURA)
The European Extremely Large Telescope
Location: Atacama Desert, Chile
Cost: €1bn (£900m)
Status: Start of operation is planned for early 2020s
Funding: European Southern Observatory
And being the first to complete their projects is crucial. The telescopes are expected to open windows into scientific mysteries that have stumped scientists for centuries.
The Giant Magellan Telescope (GMT), for instance, is currently under construction atop Las Campanas Peak in Chile at an altitude of 8,366 ft (2,550 metres) above sea level.
The GMT is a $700 million (£420 million) project being funded by the U.S, Korea and Australia and expected to be operation in around 10 years.
It will be made up of seven 27.6 ft (8.4 metre) diameter segments, and is expected to have over 5-10 times the light-gathering ability of existing instruments.
Meanwhile the €1bn (£900m) European and Extremely Large Telescope (E-ELT) being built in the Atacama Desert, Chile will have a dome that covers an area the size of a stadium.
It has a sensitivity to visible and infrared light tens of times greater than any previous telescope, and is designed to help astronomers peer back to the first galaxies 14 billion years ago.
This could unlock secrets of dark matter and dark energy – little-understood forces in space – to help explain how the universe evolved, according to the plans.
An artist's impression of the European and Extremely Large Telescope shows the Milky Way gleaming behind the telescope
The design for E-ELT followed plans for something known as the Overwhelmingly Large Telescope (Owl) which was hoped to have an aperture of 100 metres, the same distance that Usain Bolt ran in 9.58 seconds.
However, Owl had to be scrapped because of its overwhelmingly expensive budget, but Eso said it may still be built sometime in the future.
The final contender is the €1bn (£900m) Thirty Meter Telescope which had plans for its 2022 operation approved last year.
It is being constructed on Mauna Kea's peak in Hawaii which already hosts about a dozen telescopes.
The dormant volcano is popular with astronomers because its summit is well above the clouds at 13,796 feet, offering a clear view of the sky above for 300 days a year.
An artist's impression of what the Overwhelmingly Large Telescope might have looked like
It should help scientists see some 13 billion light years away for a glimpse into the early years of the universe.
The telescope's segmented primary mirror, which is nearly 100 feet (30 metres) long, will give it nine times the collecting area of the largest optical telescopes in use today. Its images will also be three times sharper.
The resulting three-way race, as ESO public information officer Richard Hook told Mark Anderson at Nautilus, is a kind of blend of cooperation and competition. ‘You could call the situation ‘Co-opetition,’ he said.
For each of the three telescope projects, much of the industrial work and projected completion dates are well-guarded secrets.
All three telescopes’ websites leave the exact projected date of their completion unknown, expressing the stating will be completed and conducting actual science by 2022.
‘I’m really hoping we’re still going to be first,’ Mr Bolte said of TMT. ‘We would have liked to have started building this telescope five years ago. I think technically we were ready to do that.’
The $1bn (£900m) Thirty Meter Telescope had plans for its 2022 operation approved last year
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CO\(_2\) Gas Sensor Using Resonant Frequency Changes in Micro-Cantilever
Our country India is facing some drastic changes in the climatic conditions due to the heating effect caused by various greenhouse gases. The most harmful gas among them is carbon dioxide and is increasing at an uncontrolled rate. This paper aims in finding out the quantity of the major polluting gas carbon dioxide. The gravimetric sensor works by absorbing the chemical in a CO\(_2\) sponge, which alters the overall mass of the sensing element i.e., a cantilever, thereby its resonant frequency. Here a micro-cantilever beam is fabricated using selective alumina—silicate gel coatings on the surface to selectively absorb CO\(_2\). As the gases are absorbed the mass increases and hence there is a change in resonant frequency. This change in frequency gives the measure of the quantity of gas present in that environment. The major expected advantage of this technique would be the repeatability of the sensor that is used.
KeywordsResonant Frequency Porous Silicon Sensitive Layer Resonance Frequency Shift Selective Coating
- 1.Voiculescu I, Zaghloul M, McGill A (2003) Cantilever gas sensor. In: Proceedings of the IEEE international symposium on circuits and systems. Bangkok, Thailand, pp 25–28Google Scholar
- 2.Roukes M (2000) Solid-state sensor and actuator workshop, Hilton Head Island, SC, pp 367–370Google Scholar
- 3.Alexis M (2008) New CO2 capturing material could make plants cleaner, ScienceDailyGoogle Scholar
- 6.Ippolito SJ, Ponzoni A, Kalantar-Zadeh K, Wlodarski W, Comini E, Faglia G, Sberveglieri G (2006) Layered WO3/ZnO/36. LiTaO3 SAW gas sensor sensitive towards ethanol vapour and humidity. Sens Actuators B, Chem 117(2):442–450Google Scholar | <urn:uuid:332327b1-c332-4dfe-88d1-214dd9865941> | 2.671875 | 432 | Academic Writing | Science & Tech. | 41.99558 | 95,595,276 |
The vibrant magentas and blues reveal the galaxy is ablaze with star formation. The galaxy, also known as the Southern Pinwheel, lies 15 million light-years away in the constellation Hydra.
This Hubble mosaic of the spiral galaxy M83 or Southern Pinwheel, lies 15 million light-years away in the constellation Hydra. It contains thousands of star clusters, hundreds of thousands of individual stars, and "ghosts" of dead stars called supernova remnants.
Image Credit: NASA, ESA/HHT/STScI/AURA/W.Blair, JHU/R.O'Connell, UV
The Hubble photograph captures thousands of star clusters, hundreds of thousands of individual stars, and “ghosts” of dead stars called supernova remnants. The galactic panorama unveils a tapestry of the drama of stellar birth and death spread across 50,000 of light years.
The newest generations of stars are forming largely in clusters on the edges of the dark spiral dust lanes. These brilliant young stellar groupings, only a few million years old, produce huge amounts of ultraviolet light that is absorbed by surrounding diffuse gas clouds, causing them to glow in pinkish hydrogen light.
Gradually, the fierce stellar winds from the youngest, most massive stars blow away the gas, revealing bright blue star clusters and giving a “Swiss Cheese” appearance to the spiral arms. These youngest star clusters are about 1 million to 10 million years old. The populations of stars up to 100 million years or older appear yellow or orange by comparison because the young blue stars have already burned out.
Interstellar “bubbles” produced by nearly 300 supernovas from massive stars have been found in this Hubble image. By studying these supernova remnants, astronomers can better understand the nature of the stars that exploded and dispersed nuclear processed chemical elements back into the galaxy, contributing to the next generation of new stars.
This image is being used to support a citizen science project titled STAR DATE: M83. The primary goal is to estimate ages for approximately 3000 star clusters. Amateur scientists will use the presence or absence of the pink hydrogen emission, the sharpness of the individual stars, and the color of the clusters to estimate ages. Participants will measure the sizes of the star clusters and any associated emission nebulae. Finally, the citizen scientists will "explore" the image, identifying a variety of objects ranging from background galaxies to supernova remnants to foreground stars.
STAR DATE: M83 is a joint collaborative effort between the Space Telescope Science Institute and Zooniverse, creators of several citizen science projects including Galaxy Zoo, Planet Hunters and the Andromeda Project (go to www.zooniverse.org to see the full list). The M83 project is scheduled to launch on Monday, January 13, 2014. People interested in exploring this remarkable image in more detail, and in directly participating in a science project, can visit: http://hubblesite.org/news/2014/04
Space Science Telescope Institute/Zooniverse project
Lynn Chandler | EurekAlert!
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
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20.07.2018 | Materials Sciences | <urn:uuid:3563eafd-4d2e-41f8-8de1-e16039637b8b> | 3.828125 | 1,207 | Content Listing | Science & Tech. | 40.455307 | 95,595,278 |
Goniomentry and trigonometry - problems
- Right triangle
Calculate the length of the remaining two sides and the angles in the rectangular triangle ABC if a = 10 cm, angle alpha = 18°40'.
- Trapezoid MO
The rectangular trapezoid ABCD with right angle at point B, |AC| = 12, |CD| = 8, diagonals are perpendicular to each other. Calculate the perimeter and area of the trapezoid.
- Trigonometric functions
In right triangle is: ? Determine the value of s and c: ? ?
- Triangle SAS
Calculate area and perimeter of the triangle, if the two sides are 51 cm and 110 cm long and angle them clamped is 130°.
From the observatory 14 m high and 32 m from the river bank, river width appears in the visual angle φ = 20°. Calculate width of the river.
- Regular 5-gon
Calculate area of the regular pentagon with side 7 cm.
The observer sees straight fence 100 m long in 30° view angle. From one end of the fence is 153 m. How far is it from the another end of the fence?
In point O acts three orthogonal forces: F1 = 20 N, F2 = 7 N and F3 = 19 N. Determine the resultant of F and the angles between F and forces F1, F2 and F3.
Determine angles of the right triangle with the hypotenuse c and legs a, b, if: ?
- IS triangle
Calculate interior angles of the isosceles triangle with base 38 cm and legs 26 cm long.
Triangle KLM is given by plane coordinates of vertices: K[-4, -18] L[-13, 15] M[-1, 8]. Calculate its area and itsinterior angles.
- Cuboid diagonal
Calculate the volume and surface area of the cuboid ABCDEFGH, which sides abc has dimensions in the ratio of 9:3:8 and if you know that the wall diagonal AC is 86 cm and angle between AC and the body diagonal AG is 25 degrees.
- Slope of track
Calculate the average slope (in promiles and even in degrees) of the rail tracks between Prievidza (309 m AMSL) and Nitra (167 m AMSL), if the track is 77 km long.
Calculate volume and surface area of the cone with diameter of the base d = 15 cm and side of cone with the base has angle 52°.
Calculate the area of regular pentagon, which diagonal is u=17.
Mast has 13 m long shadow on a slope rising from the mast foot in the direction of the shadow angle at angle 15°. Determine the height of the mast, if the sun above the horizon is at angle 33°.
Calculate the length of the side GN and diagonal QN of rectangle QGNH when given: |HN| = 25 cm and angle ∠ QGH = 28 degrees.
- Maximum area of rhombus
Calculate the interior angles at which equilateral rhombus has maximum area.
- Earth parallel
Earth's radius is 6375 km long. Calculate the length parallel of latitude 10°.
Boys run kite on a cable of 68 meters long. What is the kite altitude, if the angle from the horizontal plane is 72°?
Most natural application of trigonometry and trigonometric functions is a calculation of the triangles. Common and less common calculations of different types of triangles offers our triangle calculator. Word trigonometry comes from Greek and literally means triangle calculation. | <urn:uuid:6594df56-0620-410a-a27a-e018f1df132e> | 3.40625 | 784 | Tutorial | Science & Tech. | 68.826734 | 95,595,295 |
Last updated on January 20th, 2017
Here’s how to debug your code when using a Jupyter/iPython notebook.
Tracer()(). Here’s an example using a simple function (based on this lucid explanation).
def test_debug(y): x = 10 # One-liner to start the debugger here. from IPython.core.debugger import Tracer; Tracer()() x = x + y for i in range(10): x = x+i return x test_debug(10)
When the debugger reaches the
Tracer()() line, a small line to type in commands will appear under your cell.
Simply type in the variable names to check the values or run other commands. Below I’ve listed some practical Python PBD commands. More can be found here.
Practical Python PBD debugger commands
Just type them in the window that comes up.
n(ext) line and run this one
c(ontinue) running until next breakpoint
q(uit) the debugger
For reference, I used to used
embed(). However, I found that the debugger got stuck in loops. While I could kill it using
%exit_raise, for some reason, my
matplotlib figures would no longer be displayed until I restarted the session.
So for this reason, I recommend the
Tracer()() debugger above rather than the
embed() debugger below.
But if you are interested, please keep reading.
Old way to debug [not recommended]
Place this where you want to stop the code:
from IPython import embed; embed()
This should open up a mini terminal within the Jupyter notebook.
You can inspect variables here.
To quit type,
If you’re stuck in a loop,
Sources and hints from: | <urn:uuid:9761d36d-4cf7-46c6-8b8f-141d59641dcf> | 2.609375 | 390 | Tutorial | Software Dev. | 60.267343 | 95,595,299 |
In the world of insects, high risk of attack has led to the development of camouflage as a means for survival, especially in the larval stage. One caterpillar may look like a stick, while another disguises itself as bird droppings. Though crypsis may have its advantages, University of Florida researchers uncovered some of the most extensive evidence of caterpillars using another strategy previously best-known in adult butterflies: mimicry.
Insects use camouflage to protect themselves by looking like inanimate or inedible objects, while mimicry involves one species evolving similar warning color patterns to another.
The study in the current issue of The Annals of the Entomological Society of America helps scientists better understand how organisms depend upon one another, an important factor in predicting how disturbance of natural habitats may lead to species extinctions and loss of biodiversity.
"Mimicry in general is one of the best and earliest-studied examples of natural selection, and it can help us learn where evolutionary adaptations come from," said UF lepidopterist Keith Willmott, lead author of the study and an associate curator at the Florida Museum of Natural History on the UF campus.
Bright warning coloration has evolved in many insects with physical or chemical defenses and further research into how insects metabolize plant toxins for their own benefit has potential use in the medical field.
"It's very interesting how caterpillars can detoxify a plant's poisonous chemicals and resynthesize them for their own chemical defense or for pheromones," said Florida Museum collection coordinator and study co-author Andrei Sourakov. "We can look at the caterpillars' metabolic systems to understand how they deal with secondary plant compounds, the toxic plant substances used for centuries as tonics, spices, medicine and recreational drugs."
Based on the number of eggs laid by a single female butterfly, scientists estimate about 99 percent of caterpillars die before reaching the pupal stage. Survival tactics include sharp spines, toxic chemicals and hairs accompanied by bright warning coloration.
The study focuses on two groups of Neotropical caterpillars: Danaini of the Caribbean Island of Hispaniola and Ithomiini of the upper Amazon in eastern Ecuador. Sourakov raised and observed danaine caterpillars, including the monarch butterfly and its relatives. These species apparently form Müllerian mimicry rings, in which toxic species adopt the same warning color patterns so a predator will more quickly learn which species to avoid.
In Ecuador, Willmott and study co-author Marianne Elias, from the Muséum National d'Histoire Naturelle in Paris, found that 22 of 41 ithomiine caterpillars displayed some kind of warning coloration. Five exhibited a previously undocumented pattern with a bright yellow body and blue tips, and four were likely Batesian mimics, in which edible species adopt the coloration of an unpalatable model species for protection. These "freeloaders" only appear to have the defense mechanisms of the model species.
"They act almost like parasites, because the mimics are actually edible and therefore deceive predators without having to invest in costly resources to maintain toxicity," Willmott said. "Such a system can only be stable when the mimics are relatively rare, otherwise predators will learn the trick and attack more individuals of both mimics and models, driving models to evolve novel color patterns to escape the predators."
Mimicry may be relatively rare in caterpillars because it is more difficult for them to establish bright coloration, Willmott said. A brightly colored caterpillar has less chance of evading predators than a mobile adult butterfly.
"In adults, bright coloration may be favored by sexual selection for signaling to males and females," Willmott said. "Bright colors may be disadvantageous since they attract predators, but advantageous for attracting mates. Once established, bright colors might then be modified by natural selection for mimicry, another possible reason why mimicry seems to evolve much more frequently in adults than in caterpillars."
However, Sourakov believes mimicry is more common in caterpillars than scientists realize, but may receive less attention because larvae must be raised to adulthood to identify mimicry complexes, a process that takes weeks of lab work. Also, few collections of immature stages are maintained, and colors are not as well preserved in caterpillars.
"We know mimicry is an important ecological process for several species of animals, and I hope this study will give people incentive to further research immature stages of insects," said Andre Victor Lucci Freitas, a professor in the Instituto de Biologia at Universidade Estadual de Campinas. "We need to remember in most insects, immature stages are the most abundant."
Richard Levine | EurekAlert!
World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering | <urn:uuid:cf34654d-bae9-4bc8-ba52-c6237416d7f5> | 4.15625 | 1,651 | Content Listing | Science & Tech. | 27.808485 | 95,595,307 |
The Java programming language the first born of The Green Project, which runs for 18 months, from early 1991 to summer 1992. The project is not using a version called Oak. The project was initiated by Patrick Naughton, Mike Sheridan, James Gosling and Bill Joy, along with nine other programmers from Sun Microsystems. One result of this project is the Duke mascot created by Joe Palrang. Project meeting took place in an office building Sand Hill Road in Menlo Park.
Around the summer of 1992 the project was closed by generating a Java program's first Oak, which is intended to control a device with touch screen technology (touch screen), like on a PDA today. This new technology named "* 7A? ³ (Seven Star). After the era of Star Seven completed, a subsidiary of cable TV plus a few people interested in the project The Green Project. They focus their activities on an office space at 100 Hamilton Avenue, Palo Alto. The new company is getting ahead: the number of employees increased in a short time from 13 to 70 people. At this time span was also determined using the Internet as a medium that bridges the work and ideas between them.
In the early 1990s, the Internet is still a stub, which is used only in academic circles and the military. They make the browser (browser) Mosaic as the basis for beginning to create the first Java browser called Web Runner, inspired by 1980s film, Blade Runner. In the development of the first release, the Web Runner renamed Hot Java. In about March 1995, for the first time the Java source code version 1.0a2 opened. Their success was followed with news for the first time in the newspaper San Jose Mercury News on May 23, 1995. Unfortunately there are divisions among them one day at 04.00 in a hotel room Sheraton Palace. Three of the main leaders of the project, Eric Schmidt and George Paolini from Sun Microsystems along with Marc Andreessen, Netscape form.
Oak name, taken from an oak tree that grows in front of the workspace window "father of Java", James Gosling. Oak name is not used for release versions of Java as a software has been registered with a trademark, so take the name of his successor to "Java". The name is taken from the ground pure coffee beans directly from (black coffee) Gosling's favorite.
Early versions of Java
An early version of Java ditahun 1996 for a release version so called Java Version 1.0. Java version includes many standard packages are being developed at the beginning of the next version:
* Java.lang: Appropriation class basic elements.
* Java.io: The Allocation of input and output classes, including the use of the file.
* Java.util: Appropriation complementary classes such as class data structure and class calendar class.
* Java.net: Appropriation class TCP / IP, which enables to communicate with other computers using TCP / IP.
* Java.awt: Classes basis for applications with a user interface (GUI)
* Java.applet: Class basic application interface to be implemented in a web browser.
Excess Java Program
* Multiplatform. The major advantage of Java is to run on multiple platforms / operating system computer, in accordance with the principle of write once, run anywhere. With these advantages enough programmer to write a Java program and compile (modified, from a language understood by humans into machine language / bytecode) once and then the results can be run on multiple platforms without changes. This will allow a java-based program is done on the Linux operating system but run well on Microsoft Windows. Supported platforms to date are Microsoft Windows, Linux, Mac OS and Sun Solaris. Penyebanya are each operating system uses its own program (which can be downloaded from the Java site) for the meninterpretasikan bytecode.
* OOP (Object Oriented Programming - Object Oriented Programmers) which means that all aspects are contained in the Java Objects. Java is a programming language based purely oebjek. All data types are derived from base class called Object. It is very easy programmers to design, create, develop and allocate fault a base for Java programs with fast, accurate, easy and organized. These advantages make Java as one of the easiest programming language, even for the advanced functions such as communication between the computer though.
* The Complete Class Library, Java is famous for its completeness library / library (a collection of programs that are included in java programming) is very easy in use by the programmers to build applications. Completeness of the library coupled with the existence of a large Java community that constantly create new libraries to cover all application development needs.
* Style C + +, a programming language syntax such as [C + +] and attracted a lot of C + + programmers moving to Java. Currently, users of Java very much, mostly C + + programmer who moved to Java. Universities in the United States also began to migrate to teach Java to the new students because it is more easily understood by students and can be useful also for those who are not majoring in computer.
* Automatic garbage collection, has a facility setting memory usage so that the programmer does not need to do direct memory settings (as in C + + which is widely used.)
Lack of Java programs
* Write once, fix it anywhere - There are still some things that are not compatible between platforms one with another platform. For J2SE, for example, SWT-AWT bridge that until now does not work on Mac OS X.
* Easy didekompilasi. Decompilation is the reverse process of the finished code into the source code. This is possible because Java is a bytecode koe so many attributes that store high-level languages, such as class names, methods, and data types. The same thing happened to Microsoft. NET Platform. Thus, the algorithms used will be more difficult to program and easy to hide hijacked / direverse-engineer.
* Use lots of memory. The use of memory for Java-based program is much greater than the previous generation of high-level languages like C / C + + and Pascal (more specifically, Delphi and Object Pascal). Usually this is not a problem for those who use the latest technology (as trends cheap built-in memory), but a problem for those who still have to stick with the engine computer for more than 4 years old. | <urn:uuid:063c55c8-ded1-475d-a0af-26fbc795427a> | 2.5625 | 1,325 | Knowledge Article | Software Dev. | 44.675495 | 95,595,310 |
Species Detail - Red Oak (Quercus rubra) - Species information displayed is based on all datasets.
Terrestrial Map - 10kmDistribution of the number of records recorded within each 10km grid square (ITM).
Marine Map - 50kmDistribution of the number of records recorded within each 50km grid square (WGS84).
Quercus borealis var. maxima
Invasive Species: Invasive Species || Invasive Species: Invasive Species >> Medium Impact Invasive Species
4 May (recorded in 2007)
27 October (recorded in 2002)
National Biodiversity Data Centre, Ireland, Red Oak (Quercus rubra), accessed 20 July 2018, <https://maps.biodiversityireland.ie/Species/29968> | <urn:uuid:485859a8-6416-4ed5-b162-fbdf7378f46c> | 2.703125 | 165 | Structured Data | Science & Tech. | 33.035346 | 95,595,331 |
In statistics, statistical significance (or a statistically significant result) is attained when a p-value is less than the significance level. The p-value is the probability of observing an effect given that the null hypothesis is true whereas the significance or alpha (α) level is the probability of rejecting the null hypothesis given that it is true. As a matter of good scientific practice, a significance level is chosen before data collection and is usually set to 0.05 (5%). Other significance levels (e.g., 0.01) may be used, depending on the field of study.
Statistical significance is fundamental to statistical hypothesis testing. In any experiment or observation that involves drawing a sample from a population, there is always the possibility that an observed effect would have occurred due to sampling error alone. But if the p-value is less than the significance level (e.g., p < 0.05), then an investigator may conclude that the observed effect actually reflects the characteristics of the population rather than just sampling error. An investigator may then report that the result attains statistical significance, thereby rejecting the null hypothesis.
The present-day concept of statistical significance originated with Ronald Fisher when he developed statistical hypothesis testing based on p-values in the early 20th century. It was Jerzy Neyman and Egon Pearson who later recommended that the significance level be set ahead of time, prior to any data collection.
The term significance does not imply importance and the term statistical significance is not the same as research, theoretical, or practical significance. For example, the term clinical significance refers to the practical importance of a treatment effect.
The concept of statistical significance was originated by Ronald Fisher when he developed statistical hypothesis testing, which he described as "tests of significance", in his 1925 publication, Statistical Methods for Research Workers. Fisher suggested a probability of one in twenty (0.05) as a convenient cutoff level to reject the null hypothesis. In their 1933 paper, Jerzy Neyman and Egon Pearson recommended that the significance level (e.g. 0.05), which they called α, be set ahead of time, prior to any data collection.
Despite his initial suggestion of 0.05 as a significance level, Fisher did not intend this cutoff value to be fixed, and in his 1956 publication Statistical methods and scientific inference he recommended that significant levels be set according to specific circumstances.
Role in statistical hypothesis testing
Statistical significance plays a pivotal role in statistical hypothesis testing, where it is used to determine whether a null hypothesis should be rejected or retained. A null hypothesis is the general or default statement that nothing happened or changed. For a null hypothesis to be rejected as false, the result has to be identified as being statistically significant, i.e. unlikely to have occurred due to sampling error alone.
To determine whether a result is statistically significant, a researcher would have to calculate a p-value, which is the probability of observing an effect given that the null hypothesis is true. The null hypothesis is rejected if the p-value is less than the significance or α level. The α level is the probability of rejecting the null hypothesis given that it is true (type I error) and is most often set at 0.05 (5%). If the α level is 0.05, then the conditional probability of a type I error, given that the null hypothesis is true, is 5%. Then a statistically significant result is one in which the observed p-value is less than 5%, which is formally written as p < 0.05.
If an observed p-value is not lower than the significance level, then rather than simply accepting the null hypothesis, where feasible it would often appear to be appropriate to increase the sample size of the study, and see whether the significance level is then reached. Nevertheless, the practice of increasing the number of subjects may result in the smallest effect having statistical significance. In these cases, reporting effect sizes becomes particularly important.
If the α level is set at 0.05, it means that the rejection region comprises 5% of the sampling distribution. These 5% can be allocated to one side of the sampling distribution, as in a one-tailed test, or partitioned to both sides of the distribution as in a two-tailed test, with each tail (or rejection region) containing 2.5% of the distribution. One-tailed tests are more powerful than two-tailed tests, as a null hypothesis can be rejected with a less extreme result.
Stringent significance thresholds in specific fields
In specific fields such as particle physics and manufacturing, statistical significance is often expressed in multiples of the standard deviation or sigma (σ) of a normal distribution, with significance thresholds set at a much stricter level (e.g. 5σ). For instance, the certainty of the Higgs boson particle's existence was based on the 5σ criterion, which corresponds to a p-value of about 1 in 3.5 million.
Researchers focusing solely on whether their results are statistically significant might report findings that are not substantive and not replicable. To gauge the research significance of their result, researchers are therefore encouraged to always report the effect size along with p-values (in cases where the effect being tested for is defined in terms of an effect size): the effect size quantifies the strength of an effect, such as the distance between two means (cf. Cohen's d), the correlation between two variables or its square, and other measures.
- A/B testing
- ABX test
- Confidence level, the complement of the significance level
- Effect size
- Fisher's method for combining independent tests of significance
- Look-elsewhere effect
- Multiple comparisons problem
- Texas sharpshooter fallacy (gives examples of tests where the significance level was set too high)
- Reasonable doubt
- Statistical hypothesis testing
- Redmond, Carol; Colton, Theodore (2001). "Clinical significance versus statistical significance". Biostatistics in Clinical Trials. Wiley Reference Series in Biostatistics (3rd ed.). West Sussex, United Kingdom: John Wiley & Sons Ltd. pp. 35–36. ISBN 0-471-82211-6.
- Cumming, Geoff (2012). Understanding The New Statistics: Effect Sizes, Confidence Intervals, and Meta-Analysis. New York, USA: Routledge. pp. 27–28.
- Krzywinski, Martin; Altman, Naomi (30 October 2013). "Points of significance: Significance, P values and t-tests". Nature Methods (Nature Publishing Group) 10 (11): 1041–1042. doi:10.1038/nmeth.2698. Retrieved 3 July 2014.
- Sham, Pak C.; Purcell, Shaun M (17 April 2014). "Statistical power and significance testing in large-scale genetic studies". Nature Reviews Genetics (Nature Publishing Group) 15 (5): 335–346. doi:10.1038/nrg3706. Retrieved 3 July 2014.
- Johnson, Valen E. (October 9, 2013). "Revised standards for statistical evidence". Proceedings of the National Academy of Sciences (National Academies of Science). doi:10.1073/pnas.1313476110. Retrieved 3 July 2014.
- Altman, Douglas G. (1999). Practical Statistics for Medical Research. New York, USA: Chapman & Hall/CRC. p. 167. ISBN 978-0412276309.
- Devore, Jay L. (2011). Probability and Statistics for Engineering and the Sciences (8th ed.). Boston, MA: Cengage Learning. pp. 300–344. ISBN 0-538-73352-7.
- Schlotzhauer, Sandra (2007). Elementary Statistics Using JMP (SAS Press) (PAP/CDR ed.). Cary, NC: SAS Institute. pp. 166–169. ISBN 1-599-94375-1.
- Craparo, Robert M. (2007). "Significance level". In Salkind, Neil J. Encyclopedia of Measurement and Statistics 3. Thousand Oaks, CA: SAGE Publications. pp. 889–891. ISBN 1-412-91611-9.
- Sproull, Natalie L. (2002). "Hypothesis testing". Handbook of Research Methods: A Guide for Practitioners and Students in the Social Science (2nd ed.). Lanham, MD: Scarecrow Press, Inc. pp. 49–64. ISBN 0-810-84486-9.
- Sirkin, R. Mark (2005). "Two-sample t tests". Statistics for the Social Sciences (3rd ed.). Thousand Oaks, CA: SAGE Publications, Inc. pp. 271–316. ISBN 1-412-90546-X.
- Borror, Connie M. (2009). "Statistical decision making". The Certified Quality Engineer Handbook (3rd ed.). Milwaukee, WI: ASQ Quality Press. pp. 418–472. ISBN 0-873-89745-5.
- Babbie, Earl R. (2013). "The logic of sampling". The Practice of Social Research (13th ed.). Belmont, CA: Cengage Learning. pp. 185–226. ISBN 1-133-04979-6.
- Faherty, Vincent (2008). "Probability and statistical significance". Compassionate Statistics: Applied Quantitative Analysis for Social Services (With exercises and instructions in SPSS) (1st ed.). Thousand Oaks, CA: SAGE Publications, Inc. pp. 127–138. ISBN 1-412-93982-8.
- McKillup, Steve (2006). "Probability helps you make a decision about your results". Statistics Explained: An Introductory Guide for Life Scientists (1st ed.). Cambridge, United Kingdom: Cambridge University Press. pp. 44–56. ISBN 0-521-54316-9.
- Poletiek, Fenna H. (2001). "Formal theories of testing". Hypothesis-testing Behaviour. Essays in Cognitive Psychology (1st ed.). East Sussex, United Kingdom: Psychology Press. pp. 29–48. ISBN 1-841-69159-3.
- Fisher, Ronald A. (1925). Statistical Methods for Research Workers. Edinburgh, UK: Oliver and Boyd. p. 43. ISBN 0-050-02170-2.
- Quinn, Geoffrey R.; Keough, Michael J. (2002). Experimental Design and Data Analysis for Biologists (1st ed.). Cambridge, UK: Cambridge University Press. pp. 46–69. ISBN 0-521-00976-6.
- Neyman, J.; Pearson, E.S. (1933). "The testing of statistical hypotheses in relation to probabilities a priori". Mathematical Proceedings of the Cambridge Philosophical Society 29: 492–510. doi:10.1017/S030500410001152X.
- Myers, Jerome L.; Well, Arnold D.; Lorch Jr, Robert F. (2010). "The t distribution and its applications". Research Design and Statistical Analysis: Third Edition (3rd ed.). New York, NY: Routledge. pp. 124–153. ISBN 0-805-86431-8.
- Meier, Kenneth J.; Brudney, Jeffrey L.; Bohte, John (2011). Applied Statistics for Public and Nonprofit Administration (3rd ed.). Boston, MA: Cengage Learning. pp. 189–209. ISBN 1-111-34280-6.
- Healy, Joseph F. (2009). The Essentials of Statistics: A Tool for Social Research (2nd ed.). Belmont, CA: Cengage Learning. pp. 177–205. ISBN 0-495-60143-8.
- Cohen, Barry H. (2008). Explaining Psychological Statistics (3rd ed.). Hoboken, NJ: John Wiley and Sons. pp. 46–83. ISBN 0-470-00718-4.
- Friston, Karl (2012). article "Ten ironic rules for non-statistical reviewers". NeuroImage 61 (4): 1300–1310.
- Health, David (1995). An Introduction To Experimental Design And Statistics For Biology (1st ed.). Boston, MA: CRC press. pp. 123–154. ISBN 1-857-28132-2.
- Vaughan, Simon (2013). Scientific Inference: Learning from Data (1st ed.). Cambridge, UK: Cambridge University Press. pp. 146–152. ISBN 1-107-02482-X.
- Bracken, Michael B. (2013). Risk, Chance, and Causation: Investigating the Origins and Treatment of Disease (1st ed.). New Haven, CT: Yale University Press. pp. 260–276. ISBN 0-300-18884-6.
- Franklin, Allan (2013). "Prologue: The rise of the sigmas". Shifting Standards: Experiments in Particle Physics in the Twentieth Century (1st ed.). Pittsburgh, PA: University of Pittsburgh Press. pp. Ii–Iii. ISBN 0-822-94430-8.
- Clarke, GM; Anderson, CA; Pettersson, FH; Cardon, LR; Morris, AP; Zondervan, KT (February 6, 2011). "Basic statistical analysis in genetic case-control studies". Nature Protocols 6 (2): 121–33. PMID 21293453. doi:10.1038/nprot.2010.182.
- Barsh, GS; Copenhaver, GP; Gibson, G; Williams, SM (July 5, 2012). "Guidelines for Genome-Wide Association Studies". PLoS Genetics 8 (7): e1002812. PMID 22792080. doi:10.1371/journal.pgen.1002812.
- Carver, Ronald P. (1978). "The Case Against Statistical Significance Testing". Harvard Educational Review 48: 378–399.
- Ioannidis, John P. A. (2005). "Why most published research findings are false". PLoS Medicine 2: e124.
- Pedhazur, Elazar J.; Schmelkin, Liora P. (1991). Measurement, Design, and Analysis: An Integrated Approach (Student ed.). New York, NY: Psychology Press. pp. 180–210. ISBN 0-805-81063-3.
- Ziliak, Stephen and Deirdre McCloskey (2008), The Cult of Statistical Significance: How the Standard Error Costs Us Jobs, Justice, and Lives. Ann Arbor, University of Michigan Press, 2009. ISBN 978-0-472-07007-7. Reviews and reception: (compiled by Ziliak)
- Thompson, Bruce (2004). "The "significance" crisis in psychology and education". Journal of Socio-Economics 33: 607–613. doi:10.1016/j.socec.2004.09.034.
- Chow, Siu L., (1996). Statistical Significance: Rationale, Validity and Utility, Volume 1 of series Introducing Statistical Methods, Sage Publications Ltd, ISBN 978-0-7619-5205-3 – argues that statistical significance is useful in certain circumstances.
- Kline, Rex, (2004). Beyond Significance Testing: Reforming Data Analysis Methods in Behavioral Research Washington, DC: American Psychological Association.
|40x40px||Wikiversity has learning materials about Statistical significance|
- The article "Earliest Known Uses of Some of the Words of Mathematics (S)" contains an entry on Significance that provides some historical information.
- "The Concept of Statistical Significance Testing" (February 1994): article by Bruce Thompon hosted by the ERIC Clearinghouse on Assessment and Evaluation, Washington, D.C.
- "What does it mean for a result to be "statistically significant"?" (no date): an article from the Statistical Assessment Service at George Mason University, Washington, D.C. | <urn:uuid:3b6495eb-2efd-401d-aaac-34004df7f52a> | 4.21875 | 3,383 | Knowledge Article | Science & Tech. | 62.405938 | 95,595,342 |
The concentrations of total mercury (HgT) and three bio-essential elements (phosphor, potassium, sodium) were analyzed in Antarctic seal hairs from a lake core spanning the past 2000 years and collected from King George Island (63°23′S, 57°00 ′W), West Antarctica. The HgTconcentration shows a significant fluctuation while the levels of the three bio-essential elements remain almost constant. The rise and fall of the HgTconcentration in the seal hairs are found to be closely coincided with ancient activities of gold and silver mining using Hg-amalgamation process around the world, especially in the Southern Hemisphere. Briefly, HgTlevels are high during five episodes of extensive gold and silver mining activities-Rome Empire and China Han Dynasty (∼18-300 A.D.), Maya period and China Tang (750-900 A.D.), Incas civilization and Christian Kingdom (1200-1500 A.D.), New world (1650-1800 A.D.), and modern industry period (1840 A.D.-present); they are low during four time periods of reduced gold and silver mining activities-the China Han and Rome fall (since 300 A.D.), Maya fall and Wartime period in China (1050-1250 A.D.), Pizarro coming (ca. 1532 A.D.) and Independence War of South America (1800-1830 A.D.). Two profiles of HgTin other two lake cores, one affected by seal excrements and the other by penguin droppings, from the same region are similar to the one in seal hairs. The Hg concentration profile in the seal hairs is significantly correlated with the one in a peat bog of Southern Chile near King George Island. Since Hg is existent mainly at the form of methyl-mercury in seal hairs, this correlation supports a relationship and link between atmospheric mercury concentration and methyl-mercury production. Comparing with samples from American and European continents, the Antarctic seal hairs provide an archive of total mercury concentration in surface seawater of the South Ocean less affected by regional human activities, and this archive may provide a good reference for assessing the global Hg emissions, depositions and recycling in the past thousand years. © 2005 Elsevier B.V. All rights reserved.
Mendeley saves you time finding and organizing research
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Evidence of Complex Organic Molecules on Enceladus
News Jun 28, 2018 | Original Story from Southwestern Research Institute.
Using mass spectrometry data from NASA’s Cassini spacecraft, scientists found that large, carbon-rich organic molecules are ejected from cracks in the icy surface of Saturn’s moon Enceladus. Southwest Research Institute scientists think chemical reactions between the moon’s rocky core and warm water from its subsurface ocean are linked to these complex molecules.
“We are, yet again, blown away by Enceladus. Previously we’d only identified the simplest organic molecules containing a few carbon atoms, but even that was very intriguing,” said SwRI’s Dr. Christopher Glein, a space scientist specializing in extraterrestrial chemical oceanography. He is coauthor of a paper in Nature outlining this discovery. “Now we’ve found organic molecules with masses above 200 atomic mass units. That’s over ten times heavier than methane. With complex organic molecules emanating from its liquid water ocean, this moon is the only body besides Earth known to simultaneously satisfy all of the basic requirements for life as we know it.”
Prior to its deorbit in September of 2017, Cassini sampled the plume of material emerging from the subsurface of Enceladus. The Cosmic Dust Analyzer (CDA) and the SwRI-led Ion and Neutral Mass Spectrometer (INMS) made measurements both within the plume and Saturn’s E-ring, which is formed by plume ice grains escaping Enceladus’ gravity.
“Even after its end, the Cassini spacecraft continues to teach us about the potential of Enceladus to advance the field of astrobiology in an ocean world,” Glein said. “This paper demonstrates the value of teamwork in planetary science. The INMS and CDA teams collaborated to reach a deeper understanding of the organic chemistry of Enceladus’ subsurface ocean than would be possible with only one data set.”
During Cassini’s close flyby of Enceladus on Oct. 28, 2015, INMS detected molecular hydrogen as the spacecraft flew through the plume. Previous flybys provided evidence for a global subsurface ocean residing above a rocky core. Molecular hydrogen in the plume is thought to form by the geochemical interaction between water and rocks in hydrothermal environments.
“Hydrogen provides a source of chemical energy supporting microbes that live in the Earth’s oceans near hydrothermal vents,” said SwRI’s Dr. Hunter Waite, INMS principal investigator who also was a coauthor of the new paper. “Once you have identified a potential food source for microbes, the next question to ask is ‘what is the nature of the complex organics in the ocean?’ This paper represents the first step in that understanding — complexity in the organic chemistry beyond our expectations!”
“The paper’s findings also have great significance for the next generation of exploration,” Glein said. “A future spacecraft could fly through the plume of Enceladus, and analyze those complex organic molecules using a high-resolution mass spectrometer to help us determine how they were made. We must be cautious, but it is exciting to ponder that this finding indicates that the biological synthesis of organic molecules on Enceladus is possible.”
This article has been republished from materials provided by Southwest Research Institute. Note: material may have been edited for length and content. For further information, please contact the cited source.
Frank Postberg, Nozair Khawaja, Bernd Abel, Gael Choblet, Christopher R. Glein, Murthy S. Gudipati, Bryana L. Henderson, Hsiang-Wen Hsu, Sascha Kempf, Fabian Klenner, Georg Moragas-Klostermeyer, Brian Magee, Lenz Nölle, Mark Perry, René Reviol, Jürgen Schmidt, Ralf Srama, Ferdinand Stolz, Gabriel Tobie, Mario Trieloff, J. Hunter Waite. Macromolecular organic compounds from the depths of Enceladus. Nature, 2018; 558 (7711): 564 DOI: 10.1038/s41586-018-0246-4.
How do Forests Respond to Atmospheric Pollution?News
How forests respond to elevated nitrogen levels from atmospheric pollution is not always the same. While a forest is filtering nitrogen as expected, a higher percentage than previously seen is leaving the system again as the potent greenhouse gas nitrous oxide, say researchers.READ MORE | <urn:uuid:6f51dbd3-248f-4b01-a859-829afdd58dd3> | 3.421875 | 991 | Truncated | Science & Tech. | 36.092685 | 95,595,381 |
Philae probe (The Lander) on Spaceship Rosetta arrived at Comet 67P/Churyumov-Gerasimenko on Wednesday, November 12, 2014
Philae probe (The Lander) on Spaceship Rosetta arrived at Comet 67P/Churyumov-Gerasimenko on Wednesday, Nov. 12, just after 8 a.m. PST/11 a.m. EST in North America (on November 13, 2014 at ESA – European Space Agencies control centers). The lander is expected to send images from its landing site, Agilkia, the first ever taken from a comet’s surface.
Rosetta #CometLanding webcast Separation Confirmation Received on Ground
http://new.livestream.com/ESA/cometlanding/videos/67854347 This earlier video stream contained much more information than the actual landing video. That mostly showed all of the participants in
ESA – European Space Agencies control centers congratulating one another.
Here’s why the Rosetta Mission has so many Egyptian names
Agilkia Island is an island in the River Nile and the present site of an Ancient Egyptian temple complex of Philae in southern Egypt. Wikipedia
What’s the betting that Agilkia makes it into the baby name charts in 2015? This romantic, lyrical word is the name of an island in the Egyptian Nile, but it’s also just been given to the patch of Comet 67P/Churyumov-Gerasimenko where the Rosetta mission’s Philae lander is due to touch down.
More than 8,000 people from 135 different countries entered the ESA’s competition to name the landing site. More than 150 of these entrants independently suggested Agilkia. Surprised? You shouldn’t be, because this geographical reference fits beautifully with the overarching Egyptian imagery of the Rosetta mission.
It’s well known that the Rosetta spacecraft was named after the famous Rosetta stone, whose discovery in 1799 enabled historians to unlock the secrets of hieroglyphics. The choice of that name reflected the spacecraft’s role in deciphering the mysteries of the universe, while poetically linking space with time, language with science, archaeology with cosmology.
The connections continue. The Philae lander was christened in 2004 by an Italian high-school student, who made the connection between the lander and an ancient obelisk found on the island of Philae near Aswan. The obelisk was inscribed in both Greek and Egyptian characters and its discovery represented another landmark in the translation of hieroglyphics and the understanding of distant kingdoms.
Other ancient Egyptian references in the space mission include Ptolemy (after Ptolemy V, whose name appears on both the Rosetta stone and the Philae obelisk), and the on-board camera OSIRIS—an acronym for Optical, Spectroscopic, and Infra-red Remote Imaging System but also one of the most intriguing ancient Egyptian deities.
And now we have Agilkia—that enigmatic landscape which silently awaits the arrival of Philae.
Back on earth, Philae and Agilkia aren’t just neighboring islands. In the 1970s, when Philae was at risk of floods after the building of the Aswan Dam, the ancient temple complex on the island was dismantled and then re-built on Agilkia.
The journey of the Philae lander to the Agilkia comet site re-enacts this piece of rescue archaeology on a cosmic scale and sets up an almost perfect analogy between ancient Egypt and modern space travel.
Almost perfect, because the inscribed Philae obelisk wasn’t actually among the monuments dispatched to Agilkia. A British aristocrat named William John Bankes had discovered the obelisk in 1815 and taken it back to his stately home in England. Like many other Egyptian obelisks—including those plundered by “Egyptomaniac” Roman emperors—this one has ended up far from its original place of display, and now stands in impressive isolation in the gardens of a National Trust property in Dorset.
But although the Rosetta’s web of symbolism becomes complicated on close inspection, the overall Egyptian theme is still an incredibly powerful one.
Using hieroglyphs to frame the mission presents space as an entity that can—and eventually will—be deciphered. And while most of us have trouble grasping the colossal distances involved in space travel (Rosetta has travelled a cumulative distance of over 6.4 billion km), the names of ancient places, pharaohs and gods can help us to mentally reach the physical remoteness of celestial bodies.
Other symbolic resonances include the Ptolemaic system of astronomy and the infamous conspiracy theories about the alien origins of the pyramids.
Sending ancient Egypt into space makes our cosmos alive with history and myth. It makes space seem more tangible, yet simultaneously more distant. The analogy can also enhance our perceptions of the past, influencing how we regard our monumental heritage. Philae and Agilkia are currently trending on Google and Twitter—and it’s clear that the world’s attention has been refocused on these sites thanks to their appropriation by space scientists.
And at a time of increasingly strained debates about cultural patrimony it makes a refreshing change to see ancient monuments used as symbols—not of an individual or nation—but of the whole planet. Rosetta, Philae, Ptolemy and Agilkia now rise far above national or political boundaries. They have become distant representatives of our shared, earthly heritage. And in that cosmic light, they look even more noble.
This post originally appeared at The Conversation. Follow @ConversationUK on Twitter. We welcome your comments at firstname.lastname@example.org
Hear Comet 67P/Churyumov-Gerasimenko sing
Rosetta’s Plasma Consortium (RPC) has uncovered a mysterious ‘song’ that Comet 67P/Churyumov-Gerasimenko is singing into space. The comet seems to be emitting a ‘song’ in the form of oscillations in the magnetic field in the comet’s environment. It is being sung at 40-50 millihertz, far below human hearing. To make the music audible to the human ear, the frequencies have been increased in this recording: https://soundcloud.com/esaops/a-singing-comet
Many of you are familiar with NASA. Few of you may be familiar with (a few) other space programs (those that have an English Language version):
Canadian Space Agency (CSA) (French: Agence spatiale canadienne (ASC)) From Wikipedia
China National Space Agency
ESA – European Space Agencies
ISRO – Indian Space Research Organisation – Mars Orbiter Mission is India’s first interplanetary mission to planet Mars, with an orbiter craft designed to orbit Mars in an elliptical orbit . It successfully entered into an orbit around planet Mars today morning (September 24, 2014). One of the most extraordinary things that I noticed about India’s Space Research Organization was that the total costs to date is only $85 millions US dollar equivalents. Video Mars Orbiter Insertion Simulation; Launch Video PSLV-C25/Mars Orbiter Mission. – Indian Space Research Organisation – Wikipedia
Russian Federal Space Agency (From English Russia News Website) also, From Wikipedia
Russian Space Research Institute From Wikipedia
This year’s Leonids meteor shower peaks on the morning of Nov. 18.. If forecasters are correct, the shower should produce a mild but pretty sprinkling of meteors. The waning crescent moon will not substantially interfere with viewing the Leonid shower. | <urn:uuid:a34571c0-6e87-497f-a2d0-588b94f1fe57> | 3.046875 | 1,628 | Personal Blog | Science & Tech. | 34.461269 | 95,595,388 |
Carbon dating is used to determine the age of biological artifacts up to 50,000 years old.This technique is widely used on recent artifacts, but educators and students alike should note that this technique will not work on older fossils (like those of the dinosaurs alleged to be millions of years old).The age of the carbon in the rock is different from that of the carbon in the air and makes carbon dating data for those organisms inaccurate under the assumptions normally used for carbon dating.This restriction extends to animals that consume seafood in their diet.Willard Libby (1908–1980), a professor of chemistry at the University of Chicago, began the research that led him to radiocarbon dating in 1945.He was inspired by physicist Serge Korff (1906–1989) of New York University, who in 1939 discovered that neutrons were produced during the bombardment of the atmosphere by cosmic rays.Think of it like a teaspoon of cocoa mixed into a cake dough—after a while, the ‘ratio’ of cocoa to flour particles would be roughly the same no matter which part of the cake you sampled.The fact that the C doesn’t matter in a living thing—because it is constantly exchanging carbon with its surroundings, the ‘mixture’ will be the same as in the atmosphere and in all living things.
, we find that this ration is the same if we sample a leaf from a tree, or a part of your body.
Carbon-14 cannot be used to date biological artifacts of organisms that did not get their carbon dioxide from the air.
This rules out carbon dating for most aquatic organisms, because they often obtain at least some of their carbon from dissolved carbonate rock.
Korff predicted that the reaction between these neutrons and nitrogen-14, which predominates in the atmosphere, would produce carbon-14, also called radiocarbon.
Libby cleverly realized that carbon-14 in the atmosphere would find its way into living matter, which would thus be tagged with the radioactive isotope. | <urn:uuid:baade7a1-cb3c-450d-90c4-90967740b3a0> | 4 | 416 | Knowledge Article | Science & Tech. | 43.435905 | 95,595,392 |
CIRES, NOAA study finds more methane, ozone precursors and benzene than estimated by regulators
During two days of intensive airborne measurements, oil and gas operations in Colorado's Front Range leaked nearly three times as much methane, a greenhouse gas, as predicted based on inventory estimates, and seven times as much benzene, a regulated air toxic. Emissions of other chemicals that contribute to summertime ozone pollution were about twice as high as estimates, according to the new paper, accepted for publication in the American Geophysical Union's Journal of Geophysical Research: Atmospheres.
"These discrepancies are substantial," said lead author Gabrielle Petron, an atmospheric scientist with NOAA's Cooperative Institute for Research in Environmental Sciences at the University of Colorado Boulder. "Emission estimates or 'inventories' are the primary tool that policy makers and regulators use to evaluate air quality and climate impacts of various sources, including oil and gas sources. If they're off, it's important to know."
The new paper provides independent confirmation of findings from research performed from 2008-2010, also by Petron and her colleagues, on the magnitude of air pollutant emissions from oil and gas activities in northeastern Colorado. In the earlier study, the team used a mobile laboratory—sophisticated chemical detection instruments packed into a car—and an instrumented NOAA tall tower near Erie, Colorado, to measure atmospheric concentrations of several chemicals downwind of various sources, including oil and gas equipment, landfills and animal feedlots.
Back then, the scientists determined that methane emissions from oil and gas activities in the region were likely about twice as high as estimates from state and federal agencies, and benzene emissions were several times higher. In 2008, northeastern Colorado's Weld County had about 14,000 operating oil and gas wells, all located in a geological formation called the Denver-Julesburg Basin.
In May 2012, when measurements for the new analysis were collected, there were about 24,000 active oil and gas wells in Weld County. The new work relied on a different technique, too, called mass-balance. In 2012, Petron and her colleagues contracted with a small aircraft to measure the concentrations of methane and other chemicals in the air downwind and upwind of the Denver-Julesburg Basin. On the ground, NOAA wind profilers near Platteville and Greeley tracked around-the-clock wind speed and wind direction.
On two days in May 2012, conditions were ideal for mass-balance work. Petron and her team calculated that 26 metric tons of methane were emitted hourly in a region centered on Weld County. To estimate the fraction from oil and gas activities, the authors subtracted inventory estimates of methane emissions from other sources, including animal feedlots, landfills and wastewater treatment plants. Petron and her team found that during those two days, oil and gas operations in the Denver-Julesburg Basin emitted about 19 metric tons of methane per hour, 75 percent of the total methane emissions. That's about three times as large as an hourly average estimate for oil and gas operations based on Environmental Protection Agency's (EPA's) Greenhouse Gas Reporting Program (itself based on industry-reported emissions).
Petron and her colleagues combined information from the mass-balance technique and detailed chemical analysis of air samples in the laboratory to come up with emissions estimates for volatile organic compounds, a class of chemicals that contributes to ozone pollution; and benzene, an air toxic.
Benzene emissions from oil and gas activities reported in the paper are significantly higher than state estimates: about 380 pounds (173 kilograms) per hour, compared with a state estimate of about 50 pounds (25 kilograms) per hour. Car and truck tailpipes are a known source of the toxic chemical; the new results suggest that oil and gas operations may also be a significant source.
Oil-and-gas-related emissions for a subset of volatile organic compounds (VOCs), which can contribute to ground-level ozone pollution, were about 25 metric tons per hour, compared to the state inventory, which amounts to 13.1 tons. Ozone at high levels can harm people's lungs and damage crops and other plants; the northern Front Range of Colorado has been out of compliance with federal health-based 8-hour ozone standards since 2007, according to the EPA. Another CIRES- and NOAA-led paper published last year showed that oil and natural gas activities were responsible for about half of the contributions of VOCs to ozone formation in northeastern Colorado.
This summer, dozens of atmospheric scientists from NASA, the National Center for Atmospheric Research, NOAA, CIRES and other will gather in the Front Range, to participate in an intensive study of the region's atmosphere, said NCAR scientist Gabriele Pfister. With research aircraft, balloon-borne measurements, mobile laboratories and other ground-based equipment, the scientists plan to further characterize the emissions of many possible sources, including motor vehicles, power plants, industrial activities, agriculture, wildfires and transported pollution.
"This summer's field experiment will provide us the information we need to understand all the key processes that contribute to air pollution in the Front Range," Pfister said.
CIRES is a partnership of NOAA and CU-Boulder.
Authors of "A new look at methane and non-methane hydrocarbon emissions from oil and natural gas operations in the Colorado Denver-Julesburg Basin," include 26 scientists from CIRES; NOAA's Earth System Research Laboratory; the Institute for Arctic and Alpine Research at CU-Boulder; the University of California, Davis; and the University of Colorado Boulder. Funding for the work, which is published in the Journal of Geophysical Research: Atmospheres, came from the Environmental Defense Fund, NOAA (the Office of Oceanic and Atmospheric Research and the Climate Program Office) and the National Science Foundation.
Gabrielle Petron | Eurek Alert!
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
Drones survey African wildlife
11.07.2018 | Schweizerischer Nationalfonds SNF
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
13.07.2018 | Event News
13.07.2018 | Materials Sciences
13.07.2018 | Life Sciences | <urn:uuid:122e1cfb-db52-400d-b480-532b59232fc7> | 2.84375 | 1,828 | Content Listing | Science & Tech. | 31.403678 | 95,595,401 |
HOUSTON (NASA PR) — Honey, I shrunk the microscope! A miniaturized fluorescence microscope makes it possible to observe changes in living cells in microgravity. Future observations of astronauts’ cells could tell scientists important information about how the body adapts to space.
BORDEAUX, France (DLR PR) — When the parabolic flight aircraft, the Airbus A310 ZERO-G, takes off from Bordeaux-Mérignac Airport on 5 June 2018, it will be a ‘first’ in several respects: for the first time, only life science experiments will be exposed to three very different gravity conditions during a joint campaign by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), the European Space Agency (ESA) and French space agency CNES (Centre national d’études spatiales; CNES).
The idea of conducting a pure ‘life science campaign’ originated with the International Space Life Sciences Working Group (ISLSWG), an expert network at space agency level. This particular campaign includes a total of eight experiments – three of them from Germany – over three flight days. Also for the first time, a NASA life science experiment will be on board. (more…)
VANDENBERG AIR FORCE BASE, Calif. (NASA PR) — All systems are go for NASA’s next launch to the Red Planet.
The early-morning liftoff on Saturday of the Mars InSight lander will mark the first time in history an interplanetary launch will originate from the West Coast. InSight will launch from the U.S. Air Force Vandenberg Air Force Base Space Launch Complex 3E. The two-hour launch window will open on May 5 at 4:05 a.m. PDT (7:05 a.m. EDT).
WASHINGTON (NASA PR) — NASA’s next mission to Mars, Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight), is scheduled to launch Saturday, May 5, on a first-ever mission to study the heart of Mars. Coverage of prelaunch and launch activities begins Thursday, May 3, on NASA Television and the agency’s website.
InSight, the first planetary mission to take off from the West Coast, is targeted to launch at 7:05 a.m. EDT (4:05 a.m. PDT) from Space Launch Complex-3 at Vandenberg Air Force Base in California aboard a United Launch Alliance (ULA) Atlas V rocket.
BERLIN (Tesat-Spacecom PR) — At today’s press conference Airbus Defence and Space, the Institute for Communication and Navigation of the German Aerospace Center (DLR-IKN) and Tesat-Spacecom published their cooperation with the aim to equip the ISS with a high capacity direct-to-earth Laser Communication Terminal.
T-OSIRIS, how the new terminal is called, was developed in cooperation between DLR-IKN and the German spacecraft supplier Tesat-Spacecom. It complements Bartolomeo, Columbus and thus the ISS with the ability to transmit data directly to earth via optical communication.
BACKNANG, Germany 12.04.2018 Tesat PR) — Tesat’s Laser Communication Terminal for CubeSats, CubeL, is on track after recently the Critical Design Review (CDR) was successfully held at the German Aerospace Center (DLR) in Oberpfaffenhofen. This was an important milestone for the development program on the way to its demonstration mission, which is planned to launch later this year.
BREMEN, German (Airbus PR) — The first high capacity space-to-ground laser communication system is to be installed on the Bartolomeo platform of the International Space Station (ISS) as part of a collaboration between Airbus Defence and Space, the Institute of Communications and Navigation of DLR (German Aerospace Center) and Tesat-Spacecom GmbH & Co. KG. The system called OSIRIS will provide direct to earth (DTE) technology with a data rate of 10 Gbps over range of about 1.500 km.
PASADENA, Calif. (NASA PR) — NASA is about to go on a journey to study the interior of Mars. The space agency held a news conference Thursday at its Jet Propulsion Laboratory (JPL) in Pasadena, California, detailing the next mission to the Red Planet.
Scheduled to launch as early as May 5, NASA’s Interior Exploration using Seismic Investigations, Geodesy and Heat Transport (InSight), a stationary lander, will be the first-ever mission dedicated to exploring Mars’ deep interior. It also will be the first NASA mission since the Apollo moon landings to place a seismometer, a device that measures quakes, on the soil of another planet.
Friedrichshafen/Bremen, Germany (Airbus PR) – Airbus, in cooperation with IBM, is developing CIMON (Crew Interactive MObile CompanioN), an AI-based assistant for astronauts for the DLR Space Administration. The technology demonstrator, which is the size of a medicine ball and weighs around 5 kg, will be tested on the ISS by Alexander Gerst during the European Space Agency’s Horizons mission between June and October 2018.
COLOGNE, Germany (DLR PR) — The Columbus space laboratory began its journey into space on 7 February 2008 and has now been the scientific heart of European research on the International Space Station (ISS) for ten years. In microgravity, researchers gain unique insights from a wide range of disciplines from astrophysics, through materials research, to psychology and medical treatment options. The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) supervised the development and construction of the ISS module on behalf of the European Space Agency (ESA), is involved with experiments at a research level and runs the operation from its Columbus Control Center in Oberpfaffenhofen.
The Vulcain® 2.1 engine, which will power the main stage of Ariane 6, has completed a successful first test firing
The test was carried out on behalf of ArianeGroup by the DLR (German Aerospace Center) at its Lampoldshausen site
This is a version of the Ariane 5 Vulcain® 2 engine optimized for Ariane 6
Lampoldshausen, Germany, 23 January 2018 (ArianeGroup PR) — The Vulcain® 2.1 engine, developed by ArianeGroup to power the main stage of the Ariane 6 launcher, for which the maiden flight is scheduled for 2020, has just been successfully tested by the DLR (German Aerospace Center) on the P5 test facility at its site in Lampoldshausen, Germany on behalf of ArianeGroup.
In addition to the Prometheus reusable rocket engine program, European officials are pursuing a program named Callisto that aims to developing a reusable booster. SpaceNewsreports:
The French and German space agencies (CNES and DLR, respectively) have for the past two years collaborated on a scaled-down rocket that would allow Europe to practice different aspects of recovery and reuse. Callisto’s first flight is planned for 2020.
Callisto officials said the goal of the program is not to create a new vehicle in 2020 — the Ariane 6 is scheduled to debut that same year — but to establish a base of knowledge for future launch vehicles that could, maybe, be reusable.
“Prometheus and Callisto are two key elements of our future launcher preparatory roadmap,” Jean-Marc Astorg, head of CNES’s Launch Vehicles Directorate, told SpaceNews. “Prometheus is a new engine to equip Ariane 6 evolutions or brand-new launchers, and Callisto is developed to learn about reusability in Europe, which we have not done before. We are lacking an experience by operation of recovering a vehicle and reflying it. This is exactly what we would like to do with Callisto.”
Around 1 to 2 percent of Ariane 6’s 3.6-billion-euro ($4.3 billion) development budget is spent on Callisto, Astorg said, describing it as a “modest approach.” Callisto is still in a preliminary design phase, he said, with a full decision on the realization of the demonstrator anticipated this June.
SPARKS, Nev. (September 28, 2017) — Sierra Nevada Corporation (SNC) announced the execution of a Memorandum of Understanding (MOU) today, expanding its relationship with the German Aerospace Center (DLR) for further collaboration on space initiatives.
The MOU provides a framework for the two organizations to cooperate in space-related technologies and transportation utilizing the Dream Chaser® spacecraft and space habitats.
COLOGNE, Germany (DLR PR) — Space missions are a bit like a marathon with checkpoints – only once the first model of a satellite has been successfully tested will construction commence on the actual flight model.
The Eu:CROPIS satellite developed by the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), which will operate two greenhouses under Martian and lunar conditions, has now reached this milestone – construction of the flight model can now begin. The finish line is already in sight: launched by Space-X, the satellite and its scientific payload will take off for outer space on board the Falcon 9 in the second half of 2017. (more…) | <urn:uuid:6ea130d9-4dcb-4ddd-a7a7-4fb25935d905> | 2.65625 | 2,028 | Content Listing | Science & Tech. | 39.535551 | 95,595,419 |
To distinguish between alternative explanations for the presence of synchronous broods in the Miocene-Pliocene bivalve, Transennella species, we performed in situ burial experiments of the Recent species T. confusa. All Recent Transennella species are asynchronous brooders; a single brood contains all or most developmental stages. Specimens from Miocene-Pliocene deposits of California [USA] suggest that some members of this taxon were synchronous brooders, i.e., all the embryos of a brood develop simultaneously with only one developmental stage represented at any time. The presence of synchronous Transennella broods in the Miocene-Pliocene could indicate that an evolutionary change in mode of reproduction has occurred in this genus. Alternatively, asynchronous brooding in this taxon may be conservative and preferential preservation of later stages of development, or seasonal variation in reproduction, could result in a taphonomic overprint. Our burial experiments indicate that the earliest stages of development are almost entirely lost; however, there is enough preservation of the later stages of development to distinguish the two modes of reproduction. Additionally, we discovered a single fossil specimen with an asynchronous brood. Based primarily on this specimen, and observations from the burial experiments, we conclude that the fossil synchronous broods are an artifact of preservation and asynchronous brooding in Transennella is conservative.
Mendeley saves you time finding and organizing research
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Tuesday, March 6, 2012
What the Hail?
No that wasn’t hail you saw Sunday Afternoon. It’s called ‘Graupel’. It forms in very similar ways to hail in a thunderstorm but in a much colder environment.
One of the best things you can learn about the weather is: Warm air rises. I know it didn’t feel warm today, but our high of 36 is balmy compared to single digits just a few thousand feet above our heads. As this ‘warm’ at the surface rises, water droplets form. First creating clouds, then super cooled water droplets. The water droplets stay in a liquid form despite actually being colder than freezing. These super cooled water droplets collide with falling snowflakes and form the graupel you saw today!
So how do you tell the difference between hail and graupel?
-Hail forms during spring and summertime thunderstorms and is very hard. Like an ice cube.
-Graupel typically forms during heavy snow/wintery mixes and easily falls apart in your hand.
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Attention is given to the mechanics of high-speed liquid jets in terms of emergence and flight mechanics of a jet flying at speeds which are supersonic relative to the sound speed of the liquid. The question is treated experimentally via an Imacon image converter camera, and theoretically via similarity arguments and the Chaplygin transformation to evaluate liquid overcompression during jet emergence. Taylor instability effects in the jet's flight late time history are discussed along with the effects of Stokes drag on the small liquid-particle shroud around the jet. The hypothesis that subsonic (relative to the liquid sound speed) jets do not undergo the violent decompression process predicted for supersonic jets is tested in an evacuated chamber.
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Where Do Insects Go When It Rains?
Have you ever wondered where insects go when it rains? We have all seen a poor unfortunate spider washed down the plughole so we know how vulnerable they are to rushing water. Surely then, isn't rain one of their worst enemies?
Sorry, but this is one of these "it depends" things. It depends on the volume of the rain and the insect. If rain is light to moderate, most insects will take this in their stride. Just like us, they will take shelter. You may find insects under leaves or rock crevices. If the rain is light enough they may be quite happy to stay out and even enjoy it a little.
If the rain is heavy then things can be quite different. Insects that frequent water more often, like mosquitoes and water skaters will negotiate rising, flooding and flowing water with more ease. Those insects that are more used to dry land will be the most affected. Larger insects will cling to whatever shelter they can find until they are eventually washed along by running water. Depending on the insect, they will configure themselves to float on the water whilst protecting themselves. In general is not common for insects to drown. Many will simply be displaced and found themselves in new surroundings. Some, though, will inevitably perish.
Small burrowing insects - like ants - are good at finding air pockets in underground burrows, even during flooding and flowing water. They require very little oxygen and can survive for weeks using air pockets that are always available even in densely flooded areas. Once the waters subside there will be a high rate of survival amongst small insects that have found these air pockets, though ants, for example, will probably go about finding a new drier nest at the earliest opportunity.
It is thought that insects can "sense" the onset of very wet weather and make plans before us humans do. It is often observed in monsoon and rainy areas, that prior to an onslaught of wet weather, some buildings are invaded by insects looking for shelter. Of course, your house or businesses is an ideal place for ants to invade should some inclement weather come along!
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MAVs, UAVs, and Insect Flight Characteristics
MAVs and UAVs and Insect Flight Characteristics seem to have a lot in common. Millions of years of evolution in nature seem to have been one of the greatest engineering schools around.
Older C-130 Hercules Aircraft Problematic
We have certainly seen around the world many Lockheed C-130 Aircraft, which have had problems over the last five years. Many of these aircraft have in excess of 100,000 total time airframe hours on them.
Glyco Nutrients & Stem Cell Production
During the speach, Dr. Reg McDaniel talked about first seeing new stem cells in the peripheral blood of clients using glyconutrients many years ago and not recognizing these cells as stem cells.
Smart Dust and Virtual Keyboards
Using Smart Dust which is sprinkled onto a rock it maybe possible to type information into a small computer or PDA very rapidly. This could be quite handy for many things such as; Search and Rescue, Fire Fighting, Civil Air Patrol, Hikers and Mountain Climbers and of course military applications.
Hobbits and Lice
HOBBITS AND LICE:In late 2004 the media was all agog with the small hominids found on Flores Island where I had written about artifacts showing sea travel technology must have existed. I had argued with many people about the issue and their argument had some merit in that we had no proof of a connection to humans or the nearby Mungo Man.
Paper - More than Meets the Eye
We are surrounded by so much paper and card that it is easy to forget just how complex it is. There are many varieties and grades of paper materials, and whilst it is fairly easy to spot the varieties, it is far more difficult to spot the grades.
Many Sci Fi writers have discussed Earthquake predictions
Cal Tech along with the Universities in Japan are on the leading edge of this new technology and it is quickly becoming a reality. Soon we will know months in advance of an expected quake and the precise time maybe known hours or minutes before it actually comes.
How Satellite TV Systems Originated
What we know as satellite tv actually had its origins in the space race which began with the launching of the satellite Sputnik by the Russians in 1957. The first communication satellite was developed and launched by a consortium of business and government entities in 1963.
Embryonic Stem Cell
Stem cells are primitive undifferentiated cells that have the capability to form any of the 220 different types of cells in the human body. The embryonic stem cell is found in the embryo and develops into various cells that make a baby.
A Case for Human Machine Visual Interface
Animation of personified reality is intriguing, memorable and interesting as well. Perhaps we ought to remember this when letting kids watch cartoons of attacking counter parts? Or maybe this is a good way to help them better understand the Machiavellian characteristics of the species before they enter the real world, where everything is not so warm and fuzzy.
Aluminum Oxide to Disrupt Laser Weapons
In a defensive move to eliminate communication of an enemy, an offensive system using a chemical laser would be a good idea. In manufacturing we have lasers, which coat materials so they can be combined or heat-treated in the application process.
Hydro-Mini Tsunami-Perpetual Wave Making Machine
Let's describe this idea as a Self Generating a Tsunami-Perpetual Wave Pattern Making Machine to Derive Mini-Hydro Power Systems in Rivers.Hydro-Mini Tsunami-Perpetual Wave Making Machine.
Robotic MAV- Micro Air Vehicle Based on an Organic Humming Bird Model
MAV Micro Air Vehicle Based on Organic Hummingbird Model. There is no more interesting bird than a humming bird.
The Quantum Theory of Holy Languages
The quantum theory of holy languages (QTHL) encompasses the three most influential fields of knowledge: science kabbalah, quantum physics and mathematic. Applications of this theory in alternative medicine by use existing human experience has many practical statements.
Pre-empt the Radiation or Die
At West Point, in a speech, President George W. Bush shared the doctrine of pre-emption with his cadets that he articulated as a countermeasure to September 11 attacks.
Mars Surface Exploration and AFF
As we study more and more about Mars we know there is life. Unfortunately in many regions of the planet it is not so evident.
The History and Achievements of the Hubble Telescope
The Hubble Telescope is famous worldwide for its amazing images of the universe. Congress in 1977 voted to fund a project to construct the Hubble.
Magnetic Propulsion for GI Joe?
Thought of the day. I talked to an old guy who gave me this idea, he wanted to create a magnet propelled anti-gravity and directional control craft.
Preventing Flooding on Individual Farmers Fields to Save Crops
I propose permits be given to farmers to they can set up along the edge of their fields a microwave array to burn a hole in the clouds when severe weather threatens their crops. I would propose that this concept be completely privately funded and be done in conjunction with the FAA.
That Dust on Your Car May Soon Be Smarter Than You Think?
Here is a thought to get this topic started. A thought on a smart dust design.
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Overview and Empiric Results for Gotland
At the very beginning of the project, a primary goal of the Gotland study was to piece together in a quantifiable way the intricate flows of energy associated with both human and natural systems. This emphasis was, perhaps, made more immediate in the middle of the 1970s following the 1973 oil embargo and the turbulence of the world energy picture in terms of oil disruptions, shortages, and price increases. However, this is not to say that the Gotland project was limited to an “energy” study; rather, the roots of our approach were derived from systems ecology, which is a framework that led naturally to an integrated representation of the region in terms of resource (with the emphasis on energy), economic, environmental, historic and cultural considerations. The unique approach of the study was its emphasis on the interaction of various aspects of the region and, in particular, the coupling that existed between human activity and the natural environment. Empiric testing of energy theories of development and organization of systems, such as those proposed by H.T. Odum, was also an important goal. Research focused on the island of Gotland in the Baltic Sea for several reasons. As mentioned in Chapter 1, island systems are of interest because of their special characteristics. Gotland was heavily dependent on external sources of energy and, therefore, could serve as a representative study site for other regions in similar situations. Being an island, it also had well defined boundaries, which facilitated the collection of inflow and outflow data.
KeywordsEnergy Cost Total Energy Consumption Direct Energy Renewable Energy Technology Gross Regional Product
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Time + acceleration - examples
- Reconstruction of the corridor
Calculate how many minutes will be reduced to travel 187 km long railway corridor, where the maximum speed increases from 120 km/h to 160 km/h. Calculate how many minutes will shorten travel time, if we consider that the train must stop at 6 stations, eac
- Free fall
Lloyd fall from height 7 m. Calculate the speed he hit the ground when falling with acceleration g = 9.81 m/s2
The body was thrown vertically upward at speed v0 = 79 m/s. Body height versus time describe equation ?. What is the maximum height body reach?
- Circular motion
Mass point moves moves uniformly in a circle with radius r = 3.4 m angular velocity ω = 3.6 rad/s. Calculate the period, frequency, and the centripetal acceleration of this movement.
Subway train went between two stations that gradually accelerated for 26 seconds and reached a speed of 72 km/h. At this rate, went 56 seconds. Then 16 seconds slowed to a stop. What was the distance between the stations?
Stone was pushed into the abyss: 2 seconds after we heard hitting the bottom. How deep is the abyss (neglecting air resistance)? (gravitational acceleration g = 9.81 m/s2 and the speed of sound in air v = 343 m/s)
- Train 2
The train slowed down from 90 km/h to 72 km/h in 5 seconds. How long track travel?
The aircraft flies at an altitude of 4100 m above the ground at speed 777 km/h. At what horizontal distance from the point B should be release any body from the aircraft body to fall into point B? (g = 9.81 m/s2)
The car accelerates at rate 0.5m/s2. How long travels 400 meters and what will be its speed?
- Traffic collision
When investigating a traffic accident, it was found that the driver stopped the vehicle immediately after the accident by constant braking on a 150 m track in 15 seconds. Do you approve that the driver exceeded the permitted speed (50 km/h) in the village.
Flywheel turns 450 rev/min (RPM). Determine the magnitude of the normal acceleration of the flywheel point which are at a distance of 10 cm from the rotation axis.
- G forces
Calculate deceleration of car (as multiple of gravitational acceleration g = 9.81 m/s2) which occurs when a car in a frontal collision slows down uniformly from a speed 111 km/h to 0 km/h in 1.2 meters trajectory.
- Acceleration 2
if a car traveling at a velocity of 80 m/s/south accelerated to a velocity of 100 m/s east in 5 seconds, what is the cars acceleration? using Pythagorean theorem
- The tram
The tram is moving with acceleration a = 0.3m/s2. How long it will pass the first meter of track? How long does it take 10 meters. What is its speed at the end of the 10 meters track?
- Free fall
How long does the stone fall freely into a depth of 80m? What speed will it hit the bottom of the abyss?
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Fly genetics may increase understanding of human hearing disorders
Researchers at the University of Wisconsin Medical School have found genetic evidence linking humans and fruit flies in a new way: through their hearing. The link offers the future possibility that the insects auditory system may serve as a model for understanding human deafness and other hearing disorders.
The scientists found that a mutated fruit fly gene controlling hearing and the mutated human counterpart gene both produced similar consequences: hearing loss as well as limb deformities and genital abnormalities. The mutated human gene is responsible for a disorder called Townes-Brocks syndrome. The unexpected finding was published in the Proceedings of the National Academy of Sciences Online (Sept. 2, 2003).
Dian Land | EurekAlert!
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
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We apply the mitigation hierarchy to our activities, looking for a positive overall balance of their impact on biodiversity.
Nature is the main source of resources for human life. The current economic growth model is the main culprit for the accelerated loss of biodiversity we have been witnessing. Scientists estimate that we are losing species at speeds 1,000 to 10,000 times higher than normal rates, and that 60% of the resources provided by ecosystems are either degraded or used in an unsustainable manner.
EDP commits not to build new generation facilities in areas belonging to the UNESCO's World Heritage Natural Sites and also sets a 'no net loss' target for all its new projects with significant residual impacts, until 2030. For that purpose, it has adopted a mitigation hierarchy, according to the following scheme:
This approach applies to all production and transportation activities; however, it does not overlap with the nationally applicable approach or regulations.
Sequential measures to protect biodiversity when planning and constructing new projects, i.e to mitigate their impact by minimizing it to the point of having no adverse effects, reaching at least a 'no net loss' level. By following the mitigation hierarchy, EDP:
i - Avoids: Situations are identified where impacts can be avoided, as early as in the planning and design stages, by carefully selecting the location or moment for the deployment of infrastructural elements.
ii - Minimizes: After surveying the local biodiversity situation, the Company adopts measures to minimize the duration, intensity and/or extent of the impacts that cannot be completely avoided.
iii - Restores/Rehabilitates: After the construction stage, the affected ecosystems are restored and rehabilitated, namely by re-naturalizing construction sites, temporary accesses, etc.
iv - Offsets: If the previous stages were not sufficient to nullify the project's impact on local biodiversity, the Company adopts measures to offset significant adverse residual impacts, seeking net gains for biodiversity.
A NNL goal requires the adoption of an impact mitigation hierarchy based on an adaptive and long-term management strategy that incorporates 10-year minimum monitoring and evaluation systems in order to monitor the longevity of impacts and of the recovery of affected habitats.
Baseline: A description of existing conditions which provides a starting point (e.g., pre-project biodiversity conditions) with which comparisons can be made (e.g., post-impact biodiversity conditions), thus making it possible to quantify change/alterations.
No Net Loss and Net Gain: No Net Loss (NNL) is defined as the point at which the biodiversity impacts caused by the project are offset by mitigation hierarchy measures, i.e., the point at which residual impacts are nullified. When the offsetting exceeds this point, the term used is 'net gains'.
Biodiversity Offset: These are measurable conservation outcomes resulting from initiatives designed to offset significant residual adverse impacts on biodiversity stemming from the project's implementation, after the adoption of adequate prevention, minimization and restoration or rehabilitation measures.
Baixo Sabor and Foz Tua
Recognition of the pressure of human activity on the biodiversity. Increased awareness of the economic costs this loss entails.
Governments make increasingly more demanding international commitments which aim to stop or significantly reduce the rate of loss of biodiversity, with the consequent creation of new legislation.
A society more informed and aware of efforts necessary for sustainable development which must be shared by everyone.
The increasing demand for transparency, accountability and willingness to share in the resolution of a problem that affects all humankind.
The external recognition of the company’s high performance facilitates access to credit and new markets with increasingly stringent rules in environmental matters.
The anticipation of risks, the promotion of good practices and the demand for collaboration with other entities allow the reduction of operating costs and improve environmental benefits, either by increasing the efficiency and effectiveness of processes, or by reducing the risk of delays in construction.
We promote mitigation measures to maintain the structural and functional balance of ecosystems, taking advantage of favorable conditions for some species created by the reservoir.
As compensatory measures, we recover degraded water lines and build small reservoirs for water level stabilization.
In new hydroelectric projects, habitat fragmentation is compensated by the improved quality of neighboring habitats to ensure local survival of the affected species.
Examples of other compensatory measures are the preservation of artificial spawning, water line recovery downstream and the building of fish ladders.
Reduced electricity consumption from fossil fuels, minimizing the impact of acidifying pollutants and those responsible for acid rain (NOₓ e SO₂).
We chose fuels with lower sulfur concentrations and we have implemented denitrification and desulfurization systems.
New plants have cooling towers, thus reducing the water collected for cooling.
We ensure extensive monitoring of the collisions of birds and bats with the blades of wind turbines and the cumulative effect of these.
We limit any indiscriminate access that disturbs sensitive species and habitats.
We promote measures to mitigate the environmental impact of different stages of wind projects: design, construction, operation and decommissioning of the project.
As an avoiding measure, we detour paths to bypass more sensitive ecological areas.
We put signaling line devices to minimize birds collision.
We promote the isolation of overhead lines to avoid electrocution.
We ensure sustainable practices in the management of vegetation in buffer strips, so reducing or nullifying negative impacts on surrounding habitats. | <urn:uuid:4a077389-4828-4ba2-8dc0-65bb452d099c> | 2.859375 | 1,106 | About (Org.) | Science & Tech. | 13.39593 | 95,595,564 |
Frit flies reach body lengths of 2-7 mm. Their bodies can be yellow, orange, brown, dark brown or black in colour, depending on which species they are. They have strong mouth parts, but their front wings and halteres are often weak. They do not fly, but use their strong, well-developed, hairy legs to move.
Frit flies are mainly active in autumn and can often be found in large numbers on lawns. Frit flies also often enter human dwellings, en masse where they are perceived as an annoyance.
Frit flies feed on sugary liquids such as nectar or honeydew. The females lay their eggs on the leaves of plants (mostly grasses), mushrooms, flowers or fruits. The hatched larvae then live inside the plants on which they feed. Some species of larvae prey on insects, other species feed on dead plant parts.
|Further chapters of "Frit Flies - Grass Flies"|
|Description of images / photos|
Photography with Cameras
Nikon D3x, Nikon D300, Canon 50D
Image editing with Photoshop
|1. ||Yellow swarming fly|
|grass flies (30)|
|frit flies (15)|
|grass insects pictures (6)|
|grass flys (4)|
|Chlorops pumilionis (4)|
|Frit Fly pictures (3)|
|flies in grass (3)|
|grass flies pictures (2)|
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Loblolly Pine Genome Sequenced
News Mar 20, 2014
To look at the humble loblolly pine – grown in neat rows on large farms throughout the southeastern U.S. and milled for things like building lumber and paper – you would never think that its genetic code is seven times larger than a human’s.
That is just one of the things researchers, including two from the University of Florida’s Institute of Food and Agricultural Sciences and the UF Genetics Institute, learned as they sequenced the loblolly pine genome for the first time. They also discovered genes resistant to a devastating pine forest disease.
It is described in the March issues of GENETICS and the journal Genome Biology.
The tree is the primary source of pulpwood and saw timber for the U.S. forest products industry.
The size and complexity of conifer genomes has, until now, prevented full genome sequencing. To sequence a genome, it must first be broken down into smaller, more manageable data pieces in order for computer programs to handle them. The pieces are then assembled and annotated – or described – as scientists look at each stretch of base pairs to see which genes are present, where they are on the genome and what they do. Different genes control different traits or characteristics in the living organism. The loblolly pine genome has 22 billion base pairs, while the human genome has 3 billion.
“It’s a huge genome. But the challenge isn’t just collecting all the sequence data. The problem is assembling that sequence into order,” said David Neale, a professor of plant sciences at the University of California, Davis, who led the project.
John M. Davis, professor and associate director of the UF School of Forest Resources and Conservation, and Katherine Smith, a biological science technician with the USDA Forest Service’s Southern Institute of Forest Genetics, took the lead in annotating the genes in a portion of the genome. They were looking for genes controlling resistance to fusiform rust, a disease that infects southern pines and renders them unfit for wood products. What they found was a whole family of resistance genes.
“Commercially, it is the most economically devastating disease of the southern pines,” Davis said. “If growers didn’t have genetic resistance, we would have no pine plantations – it’s that important.”
Florida’s nearly 16 million acres of timberland supported economic activities that generated $14.7 billion in economic impact in recent years and provided nearly 90,000 full- and part-time jobs. A molecular understanding of genetic resistance is a valuable tool for forest managers as they select trees that will develop into healthy groves. More than 500 million loblolly pine seedlings with these resistance genes are planted every year throughout the U.S.
The loblolly genome research was conducted in an open-access manner, benefitting all 31 researchers at 13 universities and institutes, even before the genome sequencing effort was completed. Data have been freely available throughout the project, with three public releases starting in June 2012.
The work was supported in part by the U.S. Department of Agriculture’s National Institute of Food and Agriculture.
Davis said his work is not finished – and might never be – because annotating a genome is a process that goes on forever.
“It never stops because we are always adding meaning to the genome sequence as we learn about other genomes,” he said.
Hay Fever Risk Genes Overlap with Autoimmune DiseaseNews
In a large international study involving almost 900,000 participants, researchers from the University of Copenhagen and COPSAC have found new risk genes for hay fever. It is the largest genetic study so far on this type of allergy, which affects millions of people around the world.READ MORE
You Thought Your Bread was Stale!News
At an archaeological site in northeastern Jordan, researchers have discovered the charred remains of a flatbread baked by hunter-gatherers 14,400 years ago. It is the oldest direct evidence of bread found to date, predating the advent of agriculture by at least 4,000 years.READ MORE
ExPecto Patronum! Magical Machine Learning Tool Summons DNA Dark Matter DataNews
A new machine learning framework, dubbed ExPecto, can predict the effects of mutations in the so-called “dark matter” regions of the human genome. ExPecto pinpoints how mutations can disrupt the way genes turn on and off throughout your body. | <urn:uuid:38815368-ab82-4a15-b08c-328fd27c6f1a> | 3.328125 | 942 | News Article | Science & Tech. | 41.959221 | 95,595,611 |
What Happens When Astronauts Drop Their Tools In Space
Excerpt from audio recordings of Apollo 17 astronauts Gene Cernan and Harrison Schmitt during their first moonwalk in 1972:
123:42:22 Schmitt: Okay. [Pause] I didn’t mean to drop that, but I did.
123:42:31 Cernan: Yeah, we got to keep from dropping everything. I’ll tell you, the big lesson today…
123:42:35 Schmitt: [Garbled]
123:42:36 Cernan: Dust, I guess.
123:42:38 Schmitt: The big lesson is that it’s going to get dropped if your hands get tired.
To get a human being into space (alive) you need to wrap them in a pressurized cocoon of air so they can breathe without boiling.
Perhaps the most difficult part of spacesuit design is the glove, where engineers must create a design rigid enough to maintain pressure, yet flexible enough to bend through the full range of motion in the fingers and the wrist. Naturally, they don’t succeed—the glove used by NASA astronauts working in spacesuits today limits them to about 20% of their full range of motion, according to Ted Southern, a spacesuit designer who works with the agency.
This makes working with these gloves exhausting, and dropping stuff inevitable.
“You do almost all of your work with your hands,” says Scott Wray, who works at NASA and helps astronauts plan and execute space walks on the International Space Station. Unlike lunar expeditions, where astronauts could perambulate around on foot, today’s space workers use their hands to navigate the ISS even as they work. This can present a problem, because when you drop something in orbit, it doesn’t fall—but it can quickly drift out of reach.
“If I drop a hammer on a space walk, ninety minutes later that hammer may collide with me or the space station, causing some damage,” Wray says, referencing the time it takes the space lab to orbit the earth at more than 17,500 miles per hour. “So it’s a pretty serious deal. If [astronauts] drop something, we want them to report the mass, the velocity, the direction of travel, the dimensions of the tool… we’ve got a group here of experts who work with DOD and track those objects in orbit.”
Whatever astronauts lose control of in space becomes its own satellite. Astrophysicist Jonathan McDowell, who maintains databases of launches and satellites in orbit, has recorded the following dropped objects that have been classified as satellites.
Yes, that is a spatula in 2006. After a damaged heat shield led the Space Shuttle Columbia to break apart on re-entry, NASA experimented with ways to repair broken thermal tiles while in orbit. That included tests that simulated injecting various “goos” into the tile and spreading them with a kind of spatula. “When [Sellers] came home after the mission, he had a lot of spatulas waiting for him in his office from his astronaut co-workers,” Wray recalls.
In a June 2018 spacewalk, astronaut Drew Feustel lost a wire-tie, used to secure bundles of wires outside the station, while installing new cameras on the outside of the station.
You can see Feustel and colleague Ricky Arnold at work in this video. You can see them checking their gloves and helmets, securing wire bundles, and very carefully moving their tools across the station. (You don’t see them losing the wire-tie.)
Naturally, NASA spends a lot of time working on not dropping things. Every tool is attached to a tether that should be linked to a suit or the station at all times: Wray says astronauts learn a protocol known as “make before you break,” to remember to hook each tool down before they lose contact with it. But over the course of a six-hour spacewalk, concentration can lapse—especially when all those tethers are floating in micro-gravity and bumping into each other in your tool box.
“I also come up with the most efficient tool configuration,” Wray says. “The best way to reduce the risk of losing a tool is to reduce the number of tools on a spacewalk, but you never know if you’re going to need an extra pry bar or torque wrench in case you encounter something off-nominal.”
The good news when it comes to lost objects in low-earth orbit, about 250 miles (402 kilometers) above the earth, is that most soon drift into the atmosphere below and burn up. The most important thing is avoiding near-term damage to the space station.
“Ideally if a crew member were to drop something, we’d want it to be heading nadir—towards the earth—and in the aft direction, so its falling orbit would be lower than the space station,” Wray says. “If it went zenith, in a way, you’re sort of pushing it into a higher orbit and possibly a higher velocity, its next orbit could collide.”
Luckily, the ISS is usually equipped to boost its altitude thanks to rocket engines on the Russian module, which it does to maintain altitude and dodge orbital debris, whether created by astronauts or anyone else. | <urn:uuid:0256f8ad-28e6-4bcd-8d61-0d15ce8c6bc6> | 3.25 | 1,143 | Truncated | Science & Tech. | 52.875979 | 95,595,618 |
Three thermometers are placed in a closet, insulated box and are allowed to reach thermal equilibrium. One is calibrated in Fahrenheit degrees, one in Celsius degrees, and one in Kelvins. The Celsius thermometer reads -40 degrees; Celsius and the Kelvin thermometer read 233K. Which of the following statements is necessarily true?
A) If the temperature of the contents is increased by 10 C degrees, the reading on the Kelvin thermometer should increase by 273 K
B) The Kelvin thermometer should read -233 K.
C) The fahrenheit thermometer must read -40 degrees F
D) If water were found within the box, it must be in the liquid state.
E) The Kelvin thermometer should read -313K
A child wants to pump up a bicycle tire so that its pressure is 1.2x105 Pa above that of atmostpheric pressure. If the child uses a pump with a circular piston 0.035m in diameter, what force must the child exert?© BrainMass Inc. brainmass.com July 20, 2018, 12:32 pm ad1c9bdddf
Answer is C.
Converting Celsius to Fahrenheit, we have: F = 9(-40)/5 + 32 = -40 degrees Fahrenheit.
A is wrong because converting Celsius to Kelvin just needs additional ...
This posting contains the solution to the given problems. | <urn:uuid:d493e663-3498-49bc-9f5d-907f6cada17f> | 4.03125 | 286 | Q&A Forum | Science & Tech. | 70.09049 | 95,595,639 |
Though Australia is the world's leader in development of the scramjet, it needs partners to meet the objective of successful launch. The Defence Science and Technology Organisation (DSTO) led by the University of Queensland has put together a group of 13 to test the rocket. The launch will take place above the Arctic Circle in September.
Preparation of the rocket has begun in Norway. There is a learning curve. A lot is expected to be learned from the project. Hypersonic physics and combustion is a relatively new area of research. The aim is to be able to launch satellites cheaper. The overall cost of the launch is $14 million, believed to be money well spent.
There is no doubt that participating scientists will be nervous on day zero. The two-stage rocket will leave Andoya Rocket Range and soar to 320 kilometers. When the thrusters cease it will gently fall back to earth in a swan dive. Unfortunately, the scramjet will not be salvaged. It is set to self-destruct over the ocean.
There is an air of optimism about the flight. However, it would be wise to err on the side of caution. The European Space Agency had many failures before perfecting its technology. We can only wait and see.
Technology by Ty Buchanan | <urn:uuid:b36c08a1-3914-4b2e-89b5-d38ad1fe174a> | 2.6875 | 260 | Personal Blog | Science & Tech. | 57.963333 | 95,595,657 |
Top quark condensate
In particle physics, the top quark condensate theory (or top condensation) is an alternative to the Standard Model fundamental Higgs field, replaced by a composite field of the top quark and its antiquark. These are bound together by a new force, analogous to the binding of Cooper pairs in a BCS superconductor, or mesons in the strong interactions. The top quark can "condense" because it is comparatively heavy, with a measured mass is approximately 173 GeV (comparable to the electroweak scale), and so its Yukawa coupling is of order unity, yielding the possibility of strong coupling dynamics.
The top and antitop quarks form a bound state that is a composite Higgs boson field. This model predicts how the electroweak scale may match the top quark mass. The idea was first described by Yoichiro Nambu and subsequently by Vladimir Miransky, Masaharu Tanabashi, and Koichi Yamawaki (Is the t Quark Responsible for the Mass of W and Z Bosons?) and developed into a predictive framework, based upon the renormalization group, by William A. Bardeen, Christopher T. Hill, and Manfred Lindner in the article Minimal Dynamical Symmetry Breaking of the Standard Model[permanent dead link]. Top quark condensation is essentially based upon the "quasi-infrared fixed point" for the top quark Higgs-Yukawa coupling, proposed in 1981 by Hill in the paper Quark and Lepton Masses from Renormalization Group Fixed Points. The simplest top condensation models predicted that the Higgs boson mass would be larger than the 175 GeV top quark mass, and have now been ruled out by the LHC discovery of the Higgs boson at a mass scale of 125 GeV.
More complex schemes may still be viable. Top condensation arises naturally in Topcolor models, that are extensions of the standard model in analogy to quantum chromodynamics. To be natural, without excessive fine-tuning (i.e. to stabilize the Higgs mass from large radiative corrections), the theory requires new physics at a relatively low energy scale. Placing new physics at 10 TeV, for instance, the model predicts the top quark to be significantly heavier than observed (at about 600 GeV vs. 171 GeV). "Top Seesaw" models, also based upon Topcolor, circumvent this difficulty. These theories will ultimately be tested at the LHC in its Run-II commencing in 2015.
- Dynamical electroweak symmetry breaking with large anomalous dimension and t quark condensate. Vladimir A. Miransky, Masaharu Tanabashi, and Koichi Yamawaki, Published in Phys. Lett. B 221:177, 1989.
- Minimal Dynamical Symmetry Breaking of the Standard Model. William A. Bardeen, Christopher T. Hill, Manfred Lindner, Published in Phys. Rev. D 41:1647, 1990. | <urn:uuid:bde6c7c6-5ceb-4641-9675-780e3da703fd> | 2.65625 | 632 | Knowledge Article | Science & Tech. | 45.535802 | 95,595,679 |
Genetically engineered crops include varieties of corn, cotton and potatoes. These plants have a bacterial gene from Bacillus thuringiensis (Bt) inserted into their genome. The Bt gene codes for the synthesis of a toxin that kills insect larvae. Other crops are genetically modified to withstand a specific herbicide. While these crops can potentially feed the world’s growing population, they also pose serious risks to the natural variety of organisms, or biodiversity.
Herbicides are toxic to many species. When a herbicide is applied across agricultural landscapes, harmful chemicals enter natural ecosystems. Many believe that herbicide-resistant crops encourage increased use of herbicides, and when more herbicides are used, even more chemicals end up in natural systems. These chemicals kill native plants that feed animals and sicken amphibians directly, causing a decrease in biodiversity.
When genes from genetically modified crops enter the environment, they have the potential to disrupt natural plant communities, threaten biodiversity and enter human food supplies. In September 2000, StarLink, a variety of Bt corn unapproved for human consumption was discovered in taco shells in the United States. During the following months, StarLink was also discovered in various yellow-corn products, some outside the country. At first, some growers were suspected of ignoring agreements not to sell StarLink to mills. However, interviews with the growers revealed that many had either not received clear instructions about not selling StarLink to mills, or were told that the unapproved variety would be approved by harvest time. The exact points at which StarLink entered the supply line remain unknown, and according to a series from Cornell Cooperative Extension’s Genetically Engineered Organisms Public Issues Education Project, it may have made its way into more than half of the United States' corn supplies.
Areas where crop species originate are particularly vulnerable to out-crossing with local varieties. In Mexico, where over 100 unique varieties of corn exist, genetically engineered corn is prohibited. Despite the ban, genes from genetically engineered corn have been found in Mexican corn. Plant geneticists at U.C. Riverside have shown that gene flow from many conventionally-bred crops increases weediness in wild relatives and there are a few instances in which crop plants have become weeds. Increased weediness is a concern when genetically engineered plants are able to out-compete other species by producing more seed, dispersing pollen or seed further, or growing more vigorously in specific environments. Transgenic sunflowers can produce 50 percent more seed than their traditional counterparts and some researchers are concerned that genetically modified plants may gradually displace valuable genetic diversity.
The toxins produced by genetically engineered crops threaten biodiversity, and according to the Sierra Club, genetic engineering should be considered environmentally dangerous. A Cornell University study shows that the Bt toxin kills the larvae of beneficial, non-target species, such as moths and butterflies. Similar studies indicate a reduction of other beneficial species, including lacewings and ladybugs. The toxin also persists in the root systems of Bt corn and in plant residues long after crops are harvested and may have detrimental consequences for millions of microorganisms that live in the soil and maintain its fertility. When Bt toxin binds to soil particles, it can persists for two to three months. This can have negative impacts on aquatic and soil invertebrates, as well as nutrient cycling processes that occur in bacterial species. | <urn:uuid:e7220b62-a797-4c05-941a-ca204124c8c1> | 3.765625 | 682 | Knowledge Article | Science & Tech. | 20.873932 | 95,595,687 |
Science for Environment Policy: European Commission DG Environment News Alert Service, July 19, 2018
Scientists lack vital knowledge on rapid Arctic climate change Arctic climate change research relies on field measurements and samples that are too scarce, and patchy at best, according to a comprehensive review study. The researchers looked at thousands of scientific studies, and found that around 30% of cited studies were clustered around only two research stations in the vast Arctic region.
Spanish National Centre for Environmental Education, July 17, 2018
A scientist's final paper looks toward Earth's future climate A final scientific paper reveals new insights into one of the most complex challenges of Earth's climate: understanding and predicting future atmospheric levels of greenhouse gases and the role of the ocean and land in determining those levels.
NASA/Goddard Space Flight Center , July 17, 2018
New training workshop in Austria for climate change adaptation Climate change impacts are most visible at the local level and thus, requiring adaptation actions. For this purpose, participants were trained as climate adaptation counsellors for Austrian municipalities. The Austrian Environment Agency acted as a moderator and guide and was responsible for the organization of the course.
Austrian Environment Agency, July 10, 2018
Global warming may be twice what climate models predict Future global warming may eventually be twice as warm as projected by climate models under business-as-usual scenarios and even if the world meets the 2°C target sea levels may rise six meters or more, according to an international team of researchers from 17 countries.
University of New South Wales, July 05, 2018
Trees with grassy areas soften summer heat Trees cool their environment and "heat islands" in large cities benefit from it. However, the degree of cooling depends greatly on the tree species and the local conditions. In a German study two species of urban trees were compared.
Technical University of Munich, July 04, 2018
Higher ambition needed to meet Paris climate targets With current climate policies and efforts to increase clean power generation, the remaining use of fossil fuels in industry, transport and heating in buildings will cause enough CO2 emissions to push climate targets out of reach.
EC Joint Research Centre, July 04, 2018
Adapting to climate change: how to make it possible? How is it possible to make climate change adaptation not only more effective but also politically and institutionally viable? How can we increase the factual support from the science to the policy making community?
CMCC, June 29, 2018
SHARA project is boosting climate change adaptation in Spain and Portugal The LIFE SHARA project actions involve strengthening the Spanish adaptation knowledge platform (AdapteCCa), capacity building, and awareness raising on climate change adaptation. Its final objective is to strengthen the governance of adaptation and increase the resilience against climate change in Spain and Portugal. | <urn:uuid:f1ce0d51-0de1-47c7-be6e-469c37e35fd1> | 2.71875 | 559 | Content Listing | Science & Tech. | 20.149147 | 95,595,696 |
Heather Heying knows that a true understanding of the world comes not from the answers, but the questions as well.
The first of many radio telescope images to come.
What does it take to become an astronaut? Retired astronaut Chris Hadfield explains, along with his vision for space exploration.
A team of international scientists has pinpointed the cosmic source of a ghostly subatomic particle called a neutrino, marking the beginning of a new era in astronomy.
Signals from rare black hole-neutron star pairs could pinpoint rate at which universe is growing, researchers say.
A new study published in the Astrophysical Journal Letters provides even more reason to think Ross 128 b, the second closest exoplanet to Earth, could harbor life.
The fans supporting their teams at the World Cup in Russia are overwhelmingly white. Their teams? Not so much.
A new study on virtual embodiment explores the “surprising plasticity of the brain’s body representation,” and suggests that virtual reality representations can improve cognition.
As temperatures rise, your brain's processing power declines.
Can radiation in space limit human exploration? It's a real challenge, explains NASA's Michelle Thaller.
There is a reason why anti-vaxx attitudes are hard to shake, explains a new study.
NASA recorded an interplanetary exchange. And it sounds not entirely unlike the beginning to a certain Daft Punk song.
Animal extinction is, after all, inevitable in the natural world — some have even called it the “engine of evolution”. So why should extinction matter to us?
For millions of years, this popular color dominated the world.
When crows and ravens fight, it’s the smaller crows being the aggressor about 97% of the time. It may be them being protective of their nest or it may be competition, but ravens are the ones being bullied.
Roaming horny hippos obtained illegally by Colombian drug lord Pablo Escobar? It's a heck of a true story.
The heatwave scorching Britain is revealing the outline of ancient buildings – some previously unknown to archaeologists
But there were some serious oversights.
Virtually all young Danes have left the parental home by the time they're 34. Yet in Slovakia, almost 57% of young adults still reside in the Hotel of Mum and Dad.
The quest for "earth-like" planets may be in vain. The chances of finding another Earth are infinitesimally small, given Earth's unique chemistry and mineralogy.
Researchers study wolves in the area contaminated by the Chernobyl nuclear disaster and what happens when they leave. | <urn:uuid:43fb9287-1232-4f11-b4e4-e240dd684b38> | 2.96875 | 550 | Content Listing | Science & Tech. | 46.363002 | 95,595,730 |
Scientists at the Max Planck Institute of Biochemistry (MPIB) in Martinsried near Munich, Germany, now discovered that the protein Hub1 of this protein family has a big effect on the synthesis of proteins: Hub1 influences the way how cells translate the information that is encoded in the genes. It even allows that one gene provides the information for two proteins and thus leads to more proteins than there are genes. This mechanism could also affect the protein repertoire of humans and hence will possibly have numerous implications for health and disease. (Nature, May 25, 2011)
Each cell possesses a large number of proteins, which steer all life functions. Each protein takes on special tasks, but these can be altered through protein modifications. Particularly fascinating cases are modifications in which the proteins are modified by chemical attachment of small proteins that belong to the ubiquitin family. Ubiquitin, which was discovered in the 1970ies, is known to work as a label for degradation: proteins marked with ubiquitin are specifically recognized by the cellular shredder, the proteasome.
In the laboratory of Stefan Jentsch at the MPIB scientists identified and studied Hub1, an unusual member of the ubiquitin family. Although Hub1 has a similar structure, it functions completely different to ubiquitin and other members of this protein family. Shravan Kumar Mishra, a postdoc in the laboratory, found that Hub1 binds tightly, but not chemically linked, to the highly conserved protein Snu66. This protein is part of a cellular machine, the spliceosome, which, by a process known as “splicing”, cuts out segments of messenger RNAs (mRNAs) and pastes the remaining parts together. As mRNA molecules transport the genetic information that is stored in the genes of the chromosomes to cellular machines (ribosomes) that translate the information into proteins, splicing can significantly alter the repertoire of proteins in cells. Mishra and colleagues now discovered that binding of Hub1 to Snu66 changes the properties of this machine in a dramatic way: in the presence of Hub1 it can act on RNAs that are otherwise not spliced. In a few cases, Hub1-modified spliceosomes can even generate two different mRNAs from one single gene. In this process, which is called “alternative splicing”, one gene thus provides the information for two different proteins.
The Hub1-mediated mechanism that the Jentsch team identified may be the oldest evolved mechanism that leads to more proteins than there are genes. Mishra and co-workers found out that the mechanism they identified is conserved from single-cellular organisms like yeast to humans. As the newly discovered mechanism is expected to influence the production of a large range of proteins also in humans, the new findings will have numerous implications for human cells in health and disease.Original Publication:
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
Pollen taxi for bacteria
18.07.2018 | Technische Universität München
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Life Sciences
18.07.2018 | Materials Sciences
18.07.2018 | Health and Medicine | <urn:uuid:04df2c42-db39-4314-aa5d-68762589f315> | 3.421875 | 1,218 | Content Listing | Science & Tech. | 37.339803 | 95,595,760 |
A comet from the outer reaches of the solar system on Sunday made a rare, close pass by Mars where a fleet of robotic science probes were poised for studies.
Comet Siding Spring passed just 87,000 miles (140,000 km) from Mars, less than half the distance between Earth and the moon and 10 times closer than any known comet has passed by Earth, NASA said.
The comet, named for the Australian observatory that discovered it last year, is believed to be a first-time visitor to the inner solar system, having departed the Oort Cloud, located beyond Neptune’s orbit, more than a million years ago.
Comets are believed to be frozen remnants left over from the formation of the solar system some 4.6 billion years ago.
“This comet is on its way plunging in toward the sun, growing a tail,” astronomer David Grinspoon, with the Planetary Science Institute in Tucson, Arizona, said during a live webcast of the comet’s flyby on Slooh.com.
The comet made its closest approach to Mars at 2:27 pm EDT, hurling past at about 126,000 mph (203,000 kph).
NASA’s three Mars orbiters and two rovers, as well as orbiters owned by the European Space Agency and India were expected to monitor the comet’s approach and fly-by, which may have left Mars engulfed in a cloud of comet dust.
“The comet has never ever been closer to the sun that we think maybe Jupiter, Saturn, Uranus or Neptune’s distance. This is its first passage into what we call the ‘water-ice line,’ where it’s really starting to blow its water off,” astrophysicist Carey Lisse, with Johns Hopkins University in Laurel, Maryland, told reporters during a press conference last week.
Initially, NASA was concerned the comet’s dusty tail could pose a threat to orbiting spacecraft as it brushes past Mars. Later assessments somewhat allayed those concerns, but NASA still opted to tweak its satellites’ orbits so that they would be behind the planet during the most risky part of the flyby.
“Mars will be right at the edge of the debris cloud, so it might encounter some of the particles, or it might not,” NASA Mars scientist Rich Zurek, with the Jet Propulsion Laboratory in Pasadena, California, said in a statement.
Mars’ atmosphere, though much thinner than Earth’s, will shield NASA’s Opportunity and Curiosity rovers from comet dust, which may trigger meteor showers.
Mars also will pass directly through the comet’s coma, which is an envelope of gas and dust surrounding the comet’s nucleus, providing an unprecedented opportunity for study, Grinspoon said. “This is a really rare event.”
(Reporting by Irene Klotz; Editing by Eric Walsh) | <urn:uuid:25175d36-dda8-46d0-9b64-3f2842532227> | 3.953125 | 616 | News Article | Science & Tech. | 48.113963 | 95,595,762 |
Climate trends in the Antarctic region remain poorly characterized, owing to the brevity and scarcity of direct climate observations and the large magnitude of inter annual to decadal-scale climate variability.
As a result, the knowledge of past Antarctic temperature and climate variability is predominantly dependent on proxy records from natural archives. Paleo temperature reconstructions from Antarctica mainly rely on water stable isotope records from ice cores with the key factor controlling this proxy mainly related to temperature variations.
Early efforts to reconstruct the continental-scale temperature history of Antarctica over the past 2000 years indicated that at the continent-scale Antarctica is the only land region where the long-term cooling trend of the last 2000 years has not yet been reversed by recent significant warming.
However, this Antarctic temperature reconstruction has large uncertainties and masks important regional-scale features of Antarctica climate evolution over the last 2,000 years. | <urn:uuid:219c2c05-9305-40fd-9dee-68d98829e4b6> | 3.296875 | 172 | Knowledge Article | Science & Tech. | 0.258821 | 95,595,765 |
Form Input Labels
By Stephen Bucaro
Many of your form input elements will need an identifying label. Some input
elements like a button, should have the label inside the graphic element,
but a text box, checkbox, or radio button needs a label. A label can be just
text next to the input element, but for the visually impaired, that would not
be very helpful.
When a visually impaired person clicks on regular text, their text reader
application will read the text, but they still may not be able to see exactly
where the input element is. An html label element has a for
attribute with the same value as the id attribute of the form element that
it identifies. When a visually impaired person clicks on a label element,
their text reader application reads the text, and the related input
element receives the focus.
Shown below is an example of a label element used with a text input.
<label for="firstname">First name:</label><input type="text" id="firstname" />
Note that the label element's for attribute ("firstname") is the same
as the value of the id attribute of the text input element.
Shown below is an example of a label element used with a checkbox input element.
<input type="checkbox" id="accept" /><label for="accept">I Accept</label>
Note that the code for the label element is positioned after the code for the checkbox input element.
Shown below is an example of a label element used with radio button inputs on a form
used to select a type of pizza.
Radio buttons in a group are mutually exclusive, that is, when you set one radio button
in a group, all other radio buttons in the group are cleared. In the code shown below, the
value of the name group identifies all the buttons in the group. However each radio
button has a unique id. The value of each label element's for attribute
is the same as the value of the id attribute of the radio buton input element.
<input type="radio" name="pizza" id="regular" value="regular" /><label for="regular">Regular</label><br/>
<input type="radio" name="pizza" id="vegetarian" value="vegetarian" /><label for="vegetarian">Vegetarian</label><br/>
<input type="radio" name="pizza" id="meatlover" value="meatlover" /><label for="meatlover">Meat Lovers</label><br/>
<input type="submit" value="Order Pizza" />
Note, the value of the value attribute is whats returned to the handler defined
by the form's action attribute. In this case I don't want the form submitted to the
Using the label element with your form input elements rather than just placing
text next to them is a good idea that makes your web site more accessible.
More HTML Code:
• Text Input Box Basics
• HTML Special Characters - Character Entities
• HTML DIV Basics
• HTML title Tag
• HTML5 Spinbox Control
• Changing the Size of an Image on Your Webpage
• Set Form Controls Tab Order With tabindex Attribute
• Line Breaks in HTML
• HTML dfn Tag
• HTML abbr and acronym Tag | <urn:uuid:655f4617-5276-41d9-a819-0eb32fa1a94e> | 3.09375 | 712 | Tutorial | Software Dev. | 37.154679 | 95,595,774 |
London, March 14 (IANS) In a first, scientists have created the three-dimensional (3-D) structures of intact mammalian genomes from individual cells, leading to a potential advance of stem cells in medicine.
The 3-D structure shows how the DNA from all the chromosomes intricately folds to fit together inside the cell nuclei.
The new approach, detailed in the journal Nature, also enables researchers to determine the structures of active chromosomes inside the cell and how they interact with each other to form an intact genome.
“Visualising a genome in 3D at such an unprecedented level of detail is an exciting step forward in research and one that has been many years in the making. This detail will reveal some of the underlying principles that govern the organisation of our genomes – for example how chromosomes interact or how structure can influence whether genes are switched on or off,” said Tom Collins from Wellcome trust — a London-based non-profit.
The genome’s structure controls when and how strongly genes — particular regions of the DNA — are switched ‘on’ or ‘off,’ while playing a critical role in the development of organisms and also, when it goes awry, in disease.
The study may help study how this changes as stem cells differentiate and how decisions are made in individual developing stem cells, which may be key to realising the potential of stem cells in medicine.
“If we can apply this method to cells with abnormal genomes, such as cancer cells, we may be able to better understand what exactly goes wrong to cause disease, and how we could develop solutions to correct this,” Collins said. | <urn:uuid:28934001-9ede-43ba-be09-9f6002ee7213> | 3.671875 | 340 | News Article | Science & Tech. | 29.958565 | 95,595,780 |
The goal of the video will be to teach the user the concept of local variables and scope. An example of a locally defined variable will be given as well as an explanation of what scope is in C++. The local variable and concept of scope will be related and the relationship between the two will be explained.
This article shows you how to optimize memory allocations in C++ using placement new. Applicable especially to usecases dealing with creation of large number of objects.
A brief on problem:
Lets take example problem for simplicity:
- I have a G… | <urn:uuid:4498bbd3-acd4-4eaa-8622-b09424cc1f21> | 3.609375 | 116 | Truncated | Software Dev. | 45.36549 | 95,595,782 |
1.a) state the assumption associated with the model used to develop the Ideal Gas Law
b) hence or otherwise describe under which physical conditions does the ideal gas law applies
2. Explain why hydrogen which has one electron in its lowest state, should in principle be a metallic conductor in its solid state whereas helium which has two electrons in its lowest energy state should be an insulator.© BrainMass Inc. brainmass.com July 21, 2018, 3:18 pm ad1c9bdddf
The ideal gas equation also called ideal gas law can be written as under:
PV = nRT
This equation interrelates 4 quantities, pressure, volume, temperature and number of moles (n).
This equation is applicable only in the cases where Temperature is AROUND room temperature and pressure is AROUND 1 atmosphere. The word around here means they are not exactly 1 atmosphere or room temperature. If the pressure and temperature vary from these values ...
This Solution contains over 1000 words to aid you in understanding the Solution to this question. It also describes the ideal gas equation. | <urn:uuid:29099df0-190a-419c-8741-0fbfc0bef5ab> | 4.0625 | 222 | Q&A Forum | Science & Tech. | 48.142967 | 95,595,794 |
Fundamentals of Fluvial Geomorphology and Channel Processes
stream and deliver it to another location. Diversions are often needed for water supply, irrigation,
hydropower, flood control, or environmental reasons. The system effects and complexities are similar to
those downstream of major dams. According to Lane's balance the sediment load in the receiving stream
will be increased due to extra, transport capacity of the increased discharge. In time, the erosion of bed
sediments decreases as the slope is reduced through bed degradation.
An increase in discharge due to a flow diversion can have a significant impact on the channel plan
form as well as the vertical stability. Schumm (1977) proposed a qualitative relation similar to Lane's that
included meander wavelength. His relation states that:
where Q is the discharge, b is the width, d is the depth, S is the slope, and L is the meander wavelength.
The above relation indicates that an increase in discharge may result in an increase in the meander
wavelength which would be accomplished through accelerated erosion of the streambanks. Therefore,
whenever diversions such as this are proposed the potential for increased meander activity must be
considered. If a stream is in the process of increasing meander wavelength, then stabilization of the bends
along the existing alignment is likely to be unsuccessful and is not recommended.
Basin Wide Factors. Sometimes the changes in the controlling variables can not be attributed to
a specific upstream or downstream factor, but rather are occurring on a basin-wide basis. This often results
from a major land use change or urbanization. These changes can significantly modify the incoming
discharge and sediment loads to a channel system. For example, urbanization can increase peak flows and
reduce sediment delivery, both of which would tend to cause channel degradation in the channel system.
A land use change from forest to row crop on the other hand might cause a significant increase in the
sediment loading resulting in aggradation of the channel system. Unfortunately, it is difficult, if not
impossible, to predict when basin wide changes such as these will occur. Therefore, the best the designer
can do in most cases is to simply try to design the bank protection measures to accommodate the most
likely future changes in the watershed. For instance, if there is a possibility of future urbanization in the
upper watershed, then additional launching stone may be needed to protect the bank from the destabilizing
impact of any future bed lowering.
188.8.131.52 Complexities and Multiple Factors
Lane's balance and other geomorphic analyses of initial morphological response to system
disturbance provide a simple qualitative method for predicting the channel response to an altered condition.
However, it does not take into account the magnitude of the change and the existing morphologic condition
of the stream. For instance, according to Lane's balance a channel cutoff should induce degradation. While
this is often the case, there are many examples where there may be no observable change in the channel
morphology following the construction of cutoffs. Brice (1981) documented the stability of streams at 103
sites in different regions of the United States where channels had been relocated. He found that following | <urn:uuid:8da6386d-9863-487c-9092-5581914efd3e> | 3.6875 | 669 | Academic Writing | Science & Tech. | 29.741893 | 95,595,822 |
Posted on 24.06.2010 - 13:00 EDT in AUV NEWS by Rons_ROV_Links
On Monday, May 17, 2010, Mote Marine Laboratory scientists working in partnership with Rutgers University launched an underwater robot offshore of Southwest Florida to patrol the Gulf of Mexico for oil. The robot, called an autonomous underwater vehicle, or AUV, looks like a yellow torpedo and is equipped with a payload that can detect oil and the chemicals used to disperse it in the water.
Launched from a boat 20 miles west of Venice, the AUV will travel another 80 to 100 miles west-southwest, patrolling the Continental Shelf perpendicular to the coastline.
Thanks to a grant from the Gulf Coast Community Foundation of Venice, Mote also has funding to launch another two gliders off Florida later this week. The first - nicknamed Nemo and owned by Mote - will look for oil about 15 miles offshore between Tampa Bay and Charlotte Harbor. The second - nicknamed Waldo and owned by the National Oceanic and Atmospheric Administration - is scheduled to be deployed to the Florida Keys, where it will search for oil in the Straits of Florida - the location oil might appear if it gets carried south by the Loop Current.
Short of sending researchers out in boats to physically take water samples, this is the only way to tell what's happening under the water's surface, said Dr. Gary Kirkpatrick, manager of Mote's Phytoplankton Ecology Program who is heading up these glider missions.
"There are really large issues at stake for us here in Florida," Kirkpatrick said. "It's not really logistically possible to have humans in boats covering these wide areas, constantly looking for signs of the oil spill coming toward our shores. But we have these great robots that can do this 24 hours a day for three weeks in a row, so it's important we use these tools."
If the AUVs encounter oil, Mote can alert resource managers so they can act to protect important ecological resources and shorelines, Kirkpatrick said. This is believed to be the first time that an AUV has been equipped a payload that can detect oil and sent on a patrol mission.
In addition to supporting the glider missions, the funding from the Gulf Coast Community Foundation of Venice will help Mote researchers:
• Take samples of water, sediments, bottom dwelling organisms, and sea grass
• Sample mollusks (primarily clams and oysters)
• Sample the phytoplankton community
• Create a detailed oil response plan that covers a number of different scenarios so that our area will be well-positioned to receive federal or British Petroleum funds.
"We can't thank the Gulf Coast Community Foundation of Venice enough for this lead gift," said Dr. Kumar Mahadevan, president of Mote Marine Laboratory and Aquarium. "The impact from this spill is going to be tremendous and as the response progresses, the need for funding to understand the impact is going to be great. This grant will help cover the costs associated with doing some initial planning and fact-finding but the scope of work to determine the effects of the spill on our region's environment is quite enormous."
Quick Facts: The AUVs and their Payloads
Name: Slocum Glider, after Joshua Slocum, the first man to single-handedly sail around the world.
Conceived by: Douglas C. Webb and supported by Henry Strommel and others.
Produced by: Teledyne Webb Research
What they Do: Travel autonomously throughout the water column for 15 to 30 days at a time gathering data that is then beamed to a satellite network and then sent on to a destination site on earth.
How they Travel: In simplest terms, the Slocum Glider uses buoyancy to move throughout the water column in a vertical zigzag pattern, taking in water to move down through the water column and expelling water to return to the surface to send data.
Size: About 6 feet long and 8 inches in diameter
Weight: About 110 pounds
About the Glider's Payload: The gliders are designed so that they can carry a variety of scientific instruments, or payloads. Mote created a special payload called a BreveBuster that can detect Florida's red tide in the water.
Another type of payload - the one being used to detect oil - is a called a fluorometer. A fluorometer measures the light emitted - or fluorescence - of the water as the AUV travels in the water column. In simplest terms, the fluorometer has an LED (light-emitting diode) that sends out ultraviolet light. If the water contains certain chemical components of oil, these chemicals will absorb the light and then re-emit it as fluorescence. A detector will see this light emission and report its presence.
What the Fluorometer is Looking for: The fluorometer, which is about the size of a hockey puck, is looking for polycyclic aromatic hydrocarbons, or PAH's, and the dispersants used to break the oil down. PAHs are the chemical components of oil that are extremely toxic or carcinogenic, affecting reproduction, immune function and the health of organisms that do not die from acute exposure. | <urn:uuid:b7f157fc-ef58-49a7-b031-3b5652db2d1d> | 3.015625 | 1,086 | News Article | Science & Tech. | 43.079412 | 95,595,839 |
Many Body Techniques for Waves Propagating in Random Media
A wave propagating in disordered medium undergoes multiple scattering from inhomogeneities (the wave can be acoustic, electromagnetic, or it can represent an electron wave function). The scattered waves interfere with each other and, as a result, a certain intensity pattern (a speckle pattern) is formed within the sample. This speckle pattern is highly irregular, with large intensity variations over short distances. The irregularities are not due to noise but rather reflect the specific arrangement of the inhomogeneities (impurities) in a particular sample. This is true as long as there is no inelastic scattering within the sample, i.e. the wave propagates coherently through the entire sample (mesoscopic regime).
KeywordsSpeckle Pattern Random Medium Ladder Diagram Diamagnetic Susceptibility Relative Fluctuation
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Recent evidence demonstrates that the origins of photosynthesis can be found in deep sea hydrothermal vents, where microbes evolved to obtain energy from ejected hydrogen sulfide and methane gases. These microbes are capable of oxidizing sulfides and other gases and using them as electron donors to generate energy.
Unlike many micro-algae and plants that only use water as an electron donor to drive photosynthesis, purple bacteria such as Rhodobacter capsulatus can switch between energy sources (light or geothermal radiation) and different electron donors depending on their surrounding environment. To do this, the bacterium must carefully control the synthesis of electron transfer proteins in response to changing conditions. However, the precise mechanisms used by R. capsulatus to sense and make use of hydrogen sulfide are unclear.
Now, Takayuki Shimizu and Shinji Masuda at the Tokyo Institute of Technology, in collaboration with David P. Giedroc and Carl E. Bauer at Indiana University and researchers across Japan and the USA, have uncovered and characterized a sulfide-responsive protein, or transcriptional repressor, called SqrR, and described the mechanism by which it responds to sulfides. The findings shed light on electron donation processes in the early evolution of photosynthesis.
The team examined protein and gene responses in R. capsulatus. Genetic screening identified SqrR and showed that it acts as a sensor for reactive sulfide species inside cells. SqrR also regulates around 45% of the genes responsible for sulfide-dependent photosynthesis in R. capsulatus. It appears that, when sulfides in the surrounding environment increase, SqrR responds by binding to the sulfide molecules, thereby repressing photosynthetic electron transfer so that the bacterium can survive sulfide stress. In this way, SqrR helps maintain sulfide homeostasis in rapidly-changing environments.
Uncovering a major gene regulator like SqrR will allow scientists to examine photosynthesis in more depth, and determine how bacteria have evolved to survive in different environments. The findings may also have applications in synthetic biology.
Purple bacteria have long been used by scientists to investigate the fundamental process of photosynthesis, precisely because they have adapted over millennia to respond rapidly to, and survive, multiple environmental stressors. The ability of bacteria such as R. capsulatus to use different electron donors -- including hydrogen gas, methane and hydrogen sulfide -- and switch between different radiation sources (light or geothermal) is of great interest to researchers, particularly those working in synthetic biology.
Advances in genetic screening now enable insights into the precise molecular mechanisms that control photosynthesis. While the enzymes involved in photosynthesis in purple bacteria have already been characterized, the work by Takayuki Shimizu and his team builds on understanding of how R. capsulatus senses sulfides in its surroundings and acts either to make use of, or protect itself from, the potentially toxic molecules.
By carefully monitoring and regulating the genes that facilitate electron transfer in sulfide-dependent photosynthesis, SqrR can help the bacterium survive sulfide stress. Further investigations will elucidate the processes that enable the bacterium to switch between different electron donors, and how components within R. capsulatus' cells are synchronised in response to their immediate surroundings.
Implications of the current study
The discovery of a major gene suppressor for R. capsulatus could enable further investigations into the early evolution of photosynthesis, and may also inform applications in synthetic biology. | <urn:uuid:52822454-8502-4461-be4e-374cd3f0c44c> | 4.15625 | 717 | Knowledge Article | Science & Tech. | 11.375 | 95,595,846 |
Bifurcations Dynamics of Single Neurons and Small Networks
A bifurcation occurs when a system undergoes a qualitative change in its output as a result of a change in parameter. Under certain conditions, the voltage of a cell membrane can change from being at rest to becoming oscillatory as a result of a bifurcation. Oscillatory properties of small networks are often understood using bifurcation analysis.
What Is a Bifurcation?
The word bifurcate is commonly used to denote a split, as in “up ahead, the road bifurcates into two parts.” The use of the term in this context implies that a driver traveling on this road can make a real-time choice of being able to take one or the other branch of the road when the bifurcation point is reached. In mathematics, and in its application to neuroscience, the term bifurcation has an entirely different contextual meaning. While a mathematical bifurcation is similar in that it involves different branches, the decision on which branch is chosen is largely made a priori and depends on the...
KeywordsPeriodic Orbit Hopf Bifurcation Bifurcation Diagram Bifurcation Analysis Pitchfork Bifurcation
This work was supported in part by NSF DMS 1122291.
- Rinzel J (1987) A formal classification of bursting mechanisms in excitable systems. In: Teramoto E, Yamaguti M (eds) Mathematical topics in population biology, morphogenesis and neurosciences, vol 71, Lecture notes in biomathematics. Springer, New YorkGoogle Scholar | <urn:uuid:f3956a6d-6025-42e8-8e2d-ce6726d49331> | 3.09375 | 346 | Academic Writing | Science & Tech. | 29.608612 | 95,595,854 |
February 12, 2011
In the January/February Issue of Science Illustrated there interesting articles on pgs. 36 and 37.
The first speaks of an antimatter based engine. I first read about this in the June 1999 issue of Popular Science.
So I will assume advances in some areas have been made. Allthough it seems funding has dried up for the
time being from the current economic conditions. This sounds like a great idea if it will work and is definately
better than standard rockets. Less weight in fuel would be they could take more equipment to Mars for a colonization mission. :thumbup:
Or an outter planet moon like Europa and see what's there. :pray:
Allthough my question is that if someone actually tried to use an antimatter engine, wouldn't it blow up the ship and
everything in the imediate vicinity? ❓ A matter/antimatter explosion iirc releases the most energy know to science.
The second talks about using gamma rays to create a black hole and use it to propel the craft. 😯 That's right ladies and gentlemen a black hole.
It would work in a three step process. (Quoted from issue)
1. A billion-ton laser sends out a pulse of gamma rays, causing the rays to collapse and create an artificial black hole.
2. A million-ton ship captures the black hole.
3. The black hole emits Hawking radiation, propelling the ship.
If they could get this to work then this would be another great idea and a step up from rockets. The calculations have been done
and it's theoretically possible. However Mathematician Louis Crane (who did the calculations) says it would take hundreds
or thousands of years to do. So this would obviously be a long term project.
Also I have concerns over this method. I remember them using something similar in a movie sometime ago and it not working out well for the crew. :crazy:
Plus shackling a black hole to your ship sounds like it could suck.
What if it were true?
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Many weather events went in the record books this year, as communities were destroyed by catastrophic flooding, hurricanes, wildfires and severe storms. However, the number of reported tornadoes in 2016 will fall short of the annual average for the United States.
The year started with above-average tornado activity when February produced what is likely the second-largest February outbreak on record since 1950. Then conditions became unfavorable for tornadoes.
As of early December 2016, the preliminary tornado reports add up to 976. That is roughly a 25 percent decrease from the number of tornadoes in 2015.
The 976 preliminary count is just slightly higher than the 886 reported in 2014, which is considered the lowest count in the past 10 years. The 10-year average number of tornadoes per year across the U.S. is 1,362, according to the Storm Prediction Center (SPC).
"The year started out rather active with near- to above-normal reports through February into March, then the numbers did not keep up with the average for the rest of the spring and summer," AccuWeather Senior Meteorologist Dan Kottlowski said.
The lower counts were mostly over the main tornado-prone regions of the U.S., including the Plains and South. These areas experienced drier-than-normal weather during the warm season.
Because tornadoes require a particular mix of ingredients in order to form, the number of tornadoes is highly dependent on the prevailing weather patterns.
"The lack of deep moisture prevented the development of strong and widespread thunderstorms during much of the spring and certainly during the summer and fall seasons," Kottlowski said.
The lack of sustained and widespread thunderstorms reduces the chances for tornado development.
Tornado fatalities were also down in 2016. While the lower death toll may be linked to fewer tornadoes overall, yearly fatality numbers have been decreasing over time, regardless of the tornado count, due to improved warnings and advanced notice.
One additional factor this year may be the lack of tornado outbreaks near highly populated areas.
According to Senior Vice President of AccuWeather Enterprise Solutions Mike Smith, one of the most notable outbreaks of 2016 was a tornado swarm that hit near Dodge City, Kansas, on May 24, 2016.
"A single supercell produced at least seven tornadoes in the immediate area. At one point, three tornadoes were on the ground at the same time," Smith said. "Hundreds of tornado chasers, from multiple continents, viewed the storms."
Even though one storm produced multiple tornadoes, the overall count was still nowhere close to previous years.
"The year-to-year numbers of tornadoes vary rather significantly. As recently as 2011, we were having record high numbers of violent tornadoes," Smith said.
As for 2017, forecasters aren't able to predict the severity of the tornado season this far out.
"There is no way to forecast the annual number of tornadoes, and they do fluctuate a great deal from year to year," Smith said.
Comments that don't add to the conversation may be automatically or manually removed by Facebook or AccuWeather. Profanity, personal attacks, and spam will not be tolerated.
An 11-million ton iceberg hovers over the town of Innaarsuit in Greenland. The massive iceberg floats dangerously close to shore, threatening the small town.
Two people suffered shark bites while swimming in the water off Fire Island in Suffolk County, New York, according to NBC New York.
Newly formed Tropical Storm Ampil is set to strengthen as it tracks toward Japan’s Ryukyu Islands later this week.
A rainstorm moving up from the south will coincide with a shift in the jet stream and mark the beginning of an extended period of wet, humid conditions in the northeastern US that may last into August.
Eventualmente, la aspirante a ingeniero ambiental espera trabajar tanto con gobiernos como con corporaciones para eliminar microplásticos de los océanos de manera segura y eficiente.
Drenching thunderstorms advanced into the northeastern United States Tuesday afternoon and evening, bringing reports of flash flooding throughout the region.
Weather invariably comes into play at certain points during the Tour de France, especially when some tour stages can be greater than 100 miles in length.
Heavy spring rainfall in parts of the mid-Atlantic have triggered higher-than-average mosquito rates this season. It is estimated that mosquitoes are two to three times their normal rates. | <urn:uuid:7d0417db-2bfe-4d62-a77f-3692276d885c> | 3.234375 | 941 | News Article | Science & Tech. | 43.688667 | 95,595,870 |
Australian Striped Hawk Moth
Whole, Adult, dorsal
Orange-spotted Sun Moth
|Class:||Animals (Animalia) - Jointed Legs (Arthropoda) - Insects (Insecta)|
|Order:||Butterflies & Moths (Lepidoptera)|
|Family:||Sun Moth (:Castnioidea Castniidae)|
|Species:||Orange-spotted Sun Moth (Synemon parthenoides)|
|Other name:||Link Moth|
|Similar Species:||Klug's Xenica|
General Species Information:
Found in the Adelaide Hills
A very special thank you to Rusty Ryder for taking us to their location and pointing them out to us. In flight they looked very much like the brown butterflies around at the time. If Rusty wasn't there to point them out to us, we wouldn't have noticed them, just thinking they were fast flying brown butterflies.
A most unusual moth in that their antennae are the same as a butterflies, clubbed on the end; plus never sits with it's wings vertically together like butterflies.
As we weren't able to catch one, we have no size information, but they were smaller than the Klug's Xenica. Similar to Synemon sophia (another sun moth species). We suspect the 4th photo shows a female as the body is fatter & not as elongated as the other 3 (possibly males?). Notice the iridescence on the leading edge of the forewings (which disappears easily with a slight tilt) as well as along the trailing edge of all wings. | <urn:uuid:dff2e724-d65c-4f21-b942-1ab3001c5cc7> | 2.578125 | 342 | Knowledge Article | Science & Tech. | 42.295571 | 95,595,873 |
Modified Yeast Shows Plant Response to Key Hormone
News Sep 29, 2016
Hormones are small signaling molecules that travel between cells and deliver messages to switch on and off specific genes — affecting behavior, environmental responses and growth. Human hormones include testosterone, insulin and the aptly named growth hormone. Plant hormones are an entirely different set of chemical messengers, which modulate activities such as stem growth, leaf and flower production, root patterning and coping with environmental disruption.
These are just the sorts of tasks that plant biologists seek to understand with precision as the pressure increases to feed a growing population amid unchecked climate change. But hormones in plants affect such a wide variety of genes and plant activities that the fine details of hormone responses are — at best — murky.
Researchers at the University of Washington have developed a novel toolkit based on modified yeast cells to tease out how plant genes and proteins respond to auxin, the most ubiquitous plant hormone. Their system, described in a paper published Sept. 19 in the Proceedings of the National Academy of Sciences, allowed them to decode auxin’s basic effects on the diverse family of genes that plants utilize to detect and interpret auxin-driven messages.
“Auxin has different messages in different contexts,” said senior author and UW biology professor Jennifer Nemhauser. “One cell responds to auxin one way, while its neighbor does the exact opposite — two different responses from the same chemical. What inside these cells is happening to deliver opposite messages?”
As the most widespread plant hormone, auxin affects nearly every aspect of plant biology, including growth, development and stress response. Biologists have long known that auxin acts on stretches of DNA, called promoters, to turn nearby genes on or off. But auxin doesn’t simply turn all nearby genes on or off. With auxin, some genes turn on, others are switched off and even more nuanced responses are possible. Plant proteins mediate these varied responses by binding to auxin and then to promoters. Some proteins decrease gene expression, while others do the opposite.
“There is a large amount of cross-communication between proteins, and plants have a huge number of genes that are targets for auxin,” said Nemhauser. “That makes it incredibly difficult to decipher the basic auxin ‘code’ in plant cells.”
So Nemhauser’s team switched from plant cells to budding yeast — a single-celled fungus and popular laboratory tool. The researchers engineered yeast cells to express proteins that responded to auxin, so they could measure how auxin modified the on/off state of key plant genes that they also inserted into the cells. In essence, they jury-rigged yeast to respond to auxin. To Nemhauser, this was a simple shift in approach with a potentially huge payoff.
“We changed the perspective of this problem,” said Nemhauser. “By taking the question of auxin response out of plants and reconstructing it — piece by piece — in yeast, we were able to find out the parts that matter most.”
Nemhauser’s team could introduce different auxin-response proteins into the modified yeast cells, each time measuring how they modified gene expression in the presence of auxin. Their experiments revealed the basic “code” of auxin signaling — how specific combinations of repressing or activating proteins can bind to auxin, DNA and one another to affect cellular behavior. For example, their yeast experiments show that the gene-activating protein ARF19 must bind to an identical protein to fully switch on genes. On the other hand, many gene-silencing proteins don’t need a partner to switch off genes.
These and other simple rules were only shown clearly in the yeast system developed by Nemhauser’s team. They shed light on the complex interplay within cells that produces clear auxin-mediated messages.
“These are a complicated combination of factors within cells that, when interpreted through this interplay, yield sophisticated output signals — like ‘Should this plant invest energy into making leaves or roots?'” said Nemhauser. “And it all begins with this complex dance between auxin and auxin-responding proteins.”
Nemhauser hopes this yeast-based tool, which she developed with UW electrical engineering professor Eric Klavins, will reveal more details of auxin’s actions in plant cells. And she hopes that knowledge will empower both farmers and plant geneticists in their quest to increase crop yields and resilience in the face of droughts and climate change.
“These tools could do so much, because biological systems are more complex than anything we could engineer,” said Nemhauser. “And with the right tools and knowledge of these hormone-signaling pathways, we will know exactly which changes — minimal and targeted — will produce desired traits in crops.”
Working Together Helps Phage Overcome CRISPRNews
Surprising results show that phage join forces to overcome bacteria’s CRISPR -based immune defenses. Improved understanding of the interactions between phage and their bacterial hosts could help advance phage-based therapies and stimulate viral research.READ MORE
CRISPR Screening Reveals Sickle Cell Disease TargetNews
A key signaling protein, known as heme-regulated inhibitor (HRI), has been identified as a potential therapeutic target for the development of drugs to treat sickle cell disease, using a CRISPR screening approach.READ MORE
Big Data Study Targets Genomic Dark Matter from Ocean Floor to Gut FloraNews
An international team led by computational biologist Fran Supek at IRB Barcelona develop a machine learning method to predict unknown gene functions of microbes.The system examines and compares ‘big data’ available on the metagenomes of human and environmental microbiomes.READ MORE | <urn:uuid:d186ea73-c707-4820-ad49-1ecf67a889a3> | 3.140625 | 1,224 | News Article | Science & Tech. | 32.032154 | 95,595,878 |
Convert from String to Integer to Float and back again
As you read values off a site, there will come a time when you need to manipulate them, such as performing calculations or making comparisons. That doesn’t seem to be problem until you end up with Strings being compared to Integers.
For the most part, a value read off a page will be a string because you don’t always know what it contains. For example, “New Sales Company” is a string of characters. On the other side, 537273 is a number. However, $537,273, which you can identify as numbers is actually a String value as far as the code is concerned.
Even after you remove the dollar sign and comma, the value type will still be treated as a string because that’s how it was initially read. Comparing a string to an integer will cause a mismatch, but there is a simple way to handle that.
The ValueOf() statement allows the comparison of values as a certain type. Taking the example above, it would be read from the site as a string. We would then remove the $ and , with the ReplaceAll statement – replaceAll(“[\$,]”, “”)
As noted, that would give 537273, but it is still a string. If we wanted to see if the value was greater than 500000 or add another number to it, we can use Integer.valueOf() as in – siteDailyGrossProfit=Integer.valueOf(tempText).
This would set the variable siteDailyGrossProfit to the Integer value of tempText, which would be the dollar figure we read from the site. Because the result will be an integer, this will set siteDailyGrossProfit as an Integer.
The same would be done within an IF statement to verify if the value read is less than or equal to 0. In my test case, if a value is $0, there is an issue and I want to do something about it. Once the value is read, an IF statement would be set up as:
The same type of conversion holds true for String and Float values. As an example, calculatedMargin=(((Float.valueOf(GP) / Float.valueOf(sales)) * 100).round(1)) – calculates a percentage and rounds the result to 1 decimal place. The values were read as string, but can be multiplied and divided as Float values.
String works the same way, such as the random number example we used earlier:
WebUI.setText(findTestObject(‘Page_/Sales Plan Budget/New Prospect/Category Margin Column’, [(‘Variable’) : loop]), String.valueOf(randomNumber))
A variant is to use .toInteger, .toFloat() and .toString. In this case, the variable tempText reads the value 123456 off the site. Converting to the different types would look like:
intValue = tempText.toInteger() – Would return 123456 as an Integer
stringValue = tempText.toString() – Would return 123456 as a String
floatValue = tempText.toFloat() – Would return 123456.0 as a Float
As a final example, using a command similar to the Selenium IDE, the following will convert a value to a Integer:
intValue = Integer.parseInt(strnumber)
Other articles of interest:
- Round and Round with the For..Next in Katalon Studio
- Stripping away characters with ReplaceAll in Katalon Studio
- Filling forms with random numbers in Katalon Studio
- Conditional Statements – IF .. ELSE IF in Katalon Studio
- Recovering from Divide By 0 and Coming Back From Infinity with IsNaN and IsInfinite
- Parsing Strings in Katalon – Split, Substring and Readlines
- Getting the Length of a String and the Size of a List
- Passing multiple variables to an object in Katalon Studio
- Entering and reading text GetText, SetText and SendKeys in Katalon Studio
- Custom Keywords for Custom Functions | <urn:uuid:28357eed-5df6-4a86-aee2-2da77bf57ec9> | 3.140625 | 874 | Personal Blog | Software Dev. | 57.683072 | 95,595,887 |
Writing in the current issue (Sept. 9, 2007) of the journal Nature Chemical Biology, a team of researchers from the UW-Madison School of Pharmacy describes a novel enzyme capable of changing the chemical properties of a variety of existing drugs and small molecules to make new agents to treat cancer and fight infection.
"We're finding this enzyme glycosylates all sorts of molecules," says Jon Thorson, a UW-Madison professor of pharmaceutical sciences describing the process of adding natural sugar molecules to other chemical molecules to enhance their biological effects.
The newly evolved enzyme developed by Thorson and colleagues Gavin. J. Williams and Changsheng Zhang, according to Thorson, is akin to a "Swiss Army enzyme," a catalyst that can decorate many different chemical molecules with all sorts of sugars to alter their biological effects.
Enzymes are proteins that act as catalysts across biology, from single-celled organisms to humans. They promote chemical reactions in cells and are used widely in industry for everything from making beer and cheese to producing paper and biofuel.
They are also important for making so-called natural drugs, therapeutic agents based on the blueprints of chemicals produced in nature by plants and microorganisms. Such natural sugar-bearing chemicals are the basis for some of medicine's most potent antibiotics and anticancer drugs as exemplified by the antibiotic erythromycin and the anticancer drug doxorubicin.
Important chemical features of such drugs are natural sugars, molecules that often determine a chemical compound's biological effects. Although scientists can sometimes manipulate how sugars are added or subtracted to a chemical molecule to alter its therapeutic properties, it is difficult and not always possible to routinely modify them to enhance their beneficial effects.
The new enzyme was created by generating random mutations in genes that make a naturally occurring enzyme. The altered genes were then put into a bacterium, which fabricated a series of randomly mutated new enzymes. These enzyme variants were then tested in a high throughput screen where chemical molecules engineered to fluoresce stop glowing when a sugar is successfully attached.
"We're transferring the sugar to a beacon," Thorson explains. "When you attach a sugar, you shut off the fluorescence."
The development of the screen, according to Thorson, was critical, overcoming a key limitation in the glycosyltransferase field.
"We're assaying hundreds of very interesting drug-like molecules now with newly evolved glycosyltransferases. The ability to rapidly evolve these enzymes has opened a lot of doors."
The range of potential therapeutic agents that might be generated with the new technology includes important anti-inflammatory and anti-cancer compounds, and antibiotics.
What's more, the work could lead to the creation of a "super bug," an engineered bacterium that can perform the entire process in a laboratory dish: "There's no doubt that this is going to work in vivo," says Thorson. "We can create a bug where you feed it sugars and the compounds you want to hang those sugars on" to arrive at new medicines.
Jon Thorson | EurekAlert!
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The dangers of overcharging your plants
- Oct 4, 2016
- Fundamental Research, Department of Energy Projects
- By Igor Houwat, Geoffry Davis, David Kramer
Engineers are constantly trying to make phone batteries more efficient and lighter, and they do so by packing together very thin layers of the metal lithium. The problem is that overcharging these batteries can lead to serious damage, even fires that have been in the news recently.
It turns out that nature has been dealing with a similar problem for a long time in the process of photosynthesis, the source of energy for most life on our planet. Our food supply depends on photosynthesis being efficient, and so do some of our renewable materials. And in the effort to help feed billions more people, or to power our jets and cars with biofuels, scientists have been trying to figure out how to improve this process.
But capturing light is a dangerous business for plants. And in its latest study, published in the prestigious open-access journal, eLife (go to article), the Kramer lab has discovered that photosynthesis can often overcharge plants, potentially killing them.
Storing energy in different forms
Chloroplasts do this by using the light energy to strip electrons from water and store them in various compounds, similar to what happens when we charge batteries. But unlike batteries, plants have to store energy in different forms in order to perform different jobs. A much more fascinating picture!
The Kramer lab has been studying one of these forms of storing light energy, an electric field generated by the chloroplast. Stored across an ultra-thin membrane in the chloroplast, the field powers a process that makes ATP, an essential ‘energy currency’ needed by the plant to survive and grow.
Dangerous electric spikes
In this latest study, Geoffry Davis from Kramer’s group has discovered that too much of this electric field can cause huge problems, because it destabilizes the other parts of photosynthesis, which then end up self-destructing.
“When the field gets too large, it makes some of the electrons move backwards from the way they should,” says Dr. David Kramer Hannah Distinguished Professor in Photosynthesis and Bioenergetics at the PRL. “This wastes energy, but even worse, if these electrons end up on special chlorophyll molecules, they can transform oxygen from the air into a chemical that can damage or kill the plant. “
Scientists have known for a while that this damaging chemical is a byproduct of photosynthesis, but they haven’t known the extent to which this is a major limitation on plant productivity. The reason is that plants have been studied in bits and pieces in the lab, isolated from the organism and its environment.
With that in mind, the Kramer group, through support from the U.S. Department of Energy (Basic Energy Sciences), has developed the technologies that allow them to study photosynthesis in living plants under the conditions they experience in the real world.
And these technologies have been yielding surprising insights. According to Geoffry, “When the leaves move in the wind or clouds go by, the light hitting the leaves can flicker very rapidly. These rapid changes cause very large spikes in the electric field, enough to cause a lot of damage.”
“Think about it: these changes in light conditions happen all the time in nature.”
Inefficient natural defenses
Plants can partially protect themselves from this electric overcharge, but they do this by shedding energy that would otherwise be used productively.
The result is that, out in the field, plants typically store only about 1% of the energy that they absorb as biomass that is suitable for human use. But it’s theoretically possible to store much more.
Even worse, Geoffry says, the protective mechanisms are often too slow to protect against large spikes in electric field that happen when the light flickers.
“We need plants that can respond more rapidly so they can protect themselves without losing production efficiency. We have been looking at a wide range of different plants that do a better job and also making mutations in plants to figure out what makes them more or less sensitive. This is giving us some important clues about how to proceed.”
Aiming to grow better plants
One of the collaborators on the team, Professor William Rutherford, sums up the study’s importance nicely: “There are many ways to kill a photosynthesizer with light, but this discovery is probably the most credible in terms of mechanism and physiological relevance. These big spikes in the electric field simply replace our hand-waving explanations…that is a big step forward.”
And increasing photosynthetic efficiency, even by a small percentage (say 1 or 2 percent), could dramatically increase crop yield. More importantly, such photosynthesis-related increases would not require additional fertilizer or other inputs, an improvement over the first Green Revolution due to it being intrinsically more sustainable.
Kramer emphasizes that we are going to have to find newer ways to sustain an expanding population. “There is not much more new arable land to use. So we are going to have to breed or create more efficient plants that use the resources better. And we’ve already tapped out a lot of the ‘easy’ ways to make plants more efficient.”
Kramer concludes, “Now we have to get into the engine of photosynthesis and figure out how to squeeze a few more horsepower out of it. This is a much harder problem, but that’s where the energy losses are.”
Additional collaborators include Atsuko Kanazawa, Mark Aurel Schöttler, Kaori Kohzuma, John E. Froehlich, A. William Rutherford, Mio Satoh-Cruz, Deepika Minhas, Stefanie Tietz, and Amit Dhingra.
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