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Chemistry of Manganese
Table of contents
In today's society, Manganese is one of the few elements that humans use on a daily basis. In 1774, a Swedish scientist named Johann Gottlieb Gahn was able to isolate manganese metal by reducing the compound of manganese dioxide. Remarkably enough, manganese has been used by humans throughout the centuries.
The Roman empire used manganese in their weapons and they were able to defeat their enemies. The hardness property of manganese helped them to create strong equipment for war. Furthermore, humans have been using manganese compounds centuries before human civilization began. The history of Manganese usage traces back to the stone age era, where nomads used it as a pigment to decorate their caves and sacred places. Manganese is an element that has helped and still helps humans to improve their personal lives in various ways.
History of Manganese
Where does it come from?
One may think of Manganese as initially being in metal form, however this is not the case. Manganese is not found in nature as the free metal we like to think of. Instead Manganese exists as minerals with the additions of oxides, silicates and carbonates added to the mix. Most Maganese is obtained from ores found in locations all over the world. Manganese is also known to to lie on the ocean floor in the form of nodules, which are large lumps of metallic ores.
The atomic structure of Manganese includes four electron subshells.
More properties of Manganese:
Reactions of Manganese in the world around us
Manganese is very chemically active and it has the ability to react with various elements in chemistry which we see on a day to day basis that allow for its diversity in function and uses. Because of its valence electron configuration, it allows us to use it in different and unique ways that typically other elements cannot be used in.
Manganese and Air
By its location on the periodic table, Manganese is a little less electronegative than its neighbors which makes it a little less reactive to air. Manganese metal has the ability to burn in the presence of oxygen to form Mn3O4.
3Mn(s) + 2O2(g) → Mn3O4(s)
Manganese and Nitrogen
Manganese can react in the presence of nitrogen, which is also found in the air, to form Mn3N2.
3Mn(s) + N2(g) → Mn3N2(s)
Manganese and Water
When everything is considered under normal conditions, Manganese is not reactive with water
Manganese and Acids
Manganese dissolves readily in acidic solutions
Manganese and Halogens
Manganese reacts with the halogens of group 17 to form Manganese (II) halides. An example would be if manganese reacted with chlorine, manganese (II) chloride would form. A few example reactions are shown below, but reactions with other halogens such as with fluorine are similar.
Mn(s) + Cl2(g) → MnCl2(s)
Mn(s) + Br2(g) → MnBr2(s)
Mn(s) + I2(g) → MnI2(s)
Nuclear chemistry of Manganese
Just like many other elements in the periodic table, specifically metals, manganese is also able to form isotopes. More isotopes than the ones listed exist. However those not shown in the table are isotopes whose half-life occur to quickly to be easily found.
Uses of Manganese in our world today
Health and biology
The use of manganese in the personal health of humans and in medicine today is still as important as ever. Although many people may be wary of the importance to consume important minerals along with vitamins, many are not too familiar with the importance of the consumption of Manganese in the human diet. The existence of Manganese in the body is vital to processes on the cellular level. Without it, enzymes that are vital to life are disrupted and can cause complications in health. For example, manganese aids in the formation of connective tissue in our bodies, without it or with minimal amounts, ligaments and muscles for example are less flexible and injuries can occur more readily. However, if too much manganese is consumed then health problems such as weakness, drowsiness and even paralysis may occur. Luckily, consuming too much manganese is very rare and usually occurs to those working in mines or factories that may inhale manganese dust.
Industry and technology
The presence of Manganese in industries such as the steel industry is crucial to the success of this industry in specific. If we look back to the history of manganese presented in the beginning of this module, we can see that the use of Manganese in steel is not something recent but something from the late 1700's. Nevertheless it is still a method used today for its effects on the quality and properties of steel. Manganese is used to form an alloy in the steel which in turn results in better properties such as toughness, stiffness, wear resistance, hardness and most important strength. Manganese also helps improve the rolling and forging qualities of steel. Manganese is also responsible for coloring glass a shade of purple and can also be used in industries where glass impurities evolve due to iron impurities as Manganese can return the glass back to its normal color.
In technology, although not modern technology and as was done in 1868, Manganese is used in the invention of dry cells. It is the dioxide formed by Manganese that is used to depolarize.
1. Write out the chemical reaction between manganese and the halogen fluorine.
1. Mn(s) + F2(g) → MnF2(s)
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It has a lot of interesting numbers and references to papers that have studied extremes in various locales. But it seems to me you can always find extremes somewhere on the planet (more on that in my next post).
First, on the physical reasons why more extremes should occur in a warming world, they write:
"For some types of extreme, there are simple physical reasons why they would increase in a warming climate. If the average temperature rises, then obviously so will the number of heat records, all else remaining equal. Cold extremes will decrease, but if the probability distribution for temperature is shifted unchanged towards warmer conditions, the total number of extremes (hot plus cold) will increase. That is fundamentally because what is considered extreme is always based on past experience, and a change in climate moves us out of the familiar range.About heat extremes they write (with a lot of references to other papers):
"Warming will lead to more evaporation, too, and thus surface drying, increasing the intensity and duration of drought. Warmer air can also be expected to enhance precipitation extremes as it can hold more moisture. According to the Clausius–Clapeyron equation, for each 1 °C of warming, saturated air contains 7% more water vapour, which may rain out if conditions are right. Increased atmospheric moisture content also provides more latent energy to drive storms. Furthermore, the potential intensity of tropical storms increases with warmer sea surface temperatures, all else remaining equal.
"Such simple physical considerations thus lead us to expect certain weather extremes to increase in a warmer world. However, they are not sufficient to make firm predictions, because all else may not remain equal and a more detailed analysis is needed. First of all, to detect whether extremes have in fact increased, statistical analysis is required. For an attribution of extremes to a physical cause, modelling approaches can be used."
"Recent years have seen an exceptionally large number of recordbreaking and destructive heatwaves in many parts of the world. Several recent studies indicate that many, possibly most, of these heatwaves would not have occurred without global warming.But these are all anecdotal evidence, if you will, and the paper doesn't contain a single equation. I suspect you can always find regions that have extremes (next post). Coumou and Rahmstorf include this graph:
"In 2003, Europe suffered its hottest summer by far for at least 500 years, with temperatures in Switzerland topping the previous record by a full 2.4 °C, equivalent to 5.4 standard deviations. Greece experienced its hottest summer in 2007, with summer temperatures in Athens exceeding the 1961–1990 mean by 3.3 °C, corresponding to 3.7 standard deviations. Australia’s worst bush fires on record, following an unprecedented heatwave, ravaged the country on the ‘Black Saturday’ of February 2009 (ref. 34). In 2010, central Russia suffered its worst heatwave since records began, with the July temperature in Moscow beating the previous record by 2.5 °C (ref. 5). Finally, in July 2011, the US Southern Plains were hit by a record-breaking heatwave.
"Several recent statistical studies show that the number of heat extremes is indeed strongly increasing. Starting with daily data, a recent study with global coverage shows a widespread (73% of land area) signififcant increase in the occurrence of warm nights (warmest 10% of nights)during 1951–2003. At present, about twice as many record hot days as record cold days are being observed both in the United States and Australia. Similarly, for Europe nearly 30% of the observed daily heat records are attributable to the warming climate. The length of summer heatwaves over western Europe has almost doubled and the frequency of hot days has almost tripled over the period from 1880 to 2005 (ref. 37). In the eastern Mediterranean, the intensity, length and number of heatwaves have increased by a factor of six to eight since the 1960s (ref. 38)." | <urn:uuid:56b798cb-b988-425a-adbd-36438f2a97cf> | 2.953125 | 813 | Personal Blog | Science & Tech. | 43.327935 |
Another entry in the "is function arbitrary" series...
One of the most commonplace motifs in RNA molecules is the hairpin. The basic idea is this: the 'primary' structure of a strand of RNA is the sequence of bases, GCAU. But function doesn't depend on the primary sequence. That sequence has to be folded up into three dimensions - the 'tertiary' structure. In between primary and tertiary, we have the secondary structure, which captures most of the bonding between nucleotides in a flat, 2D picture.
An RNA hairpin's primary structure is like a palindrome, the beginning and end are mirrors of each other. For example:
It just isn't that hard for these things to form by chance. An example such as the above, with an 8 base pair stem, has a 1 in 64,000 chance of forming in a random chain. That might not sound like a lot to us humans, but to molecules where gazillions can be held in a drop of water, a lot hairpins can form! 1 in 64K is way way lower than William Dembski's Universal Probability Bound of 1 in 10^150, so even he would agree that no "Intelligent Designer" is necessary.
So if 1 in 64K of short (11 base pair) primary sequences forms a hairpin secondary structure, how many of those show stability and biological function as a tertiary (3D) structure? A good question. "Function" can be based on the choice of the base pair at the bottom of the stem, the stem pairs, and the top. But it is clear that even small, simple molecules such as these can have significant function, as shown by the existence of ribozymes (enzymes made of RNA) such as the Hairpin or Hammerhead ribozyme.
Further, really important molecules such as transfer RNA are simply 4 hairpins stuck together like Lego blocks. This structure can be broken down into the "top half", consisting of two of the hairpins, and the "bottom half", the other two. These halves could have evolved independently and then acquired new functionality when they stuck together.
A key message of ID and pure creationist propaganda is that the system of replication used in cells today is too complex to have arisen without guidance by a Creator. Looking at the reality of RNA hairpins, we can see that this is not true. A key piece of our current replication machinery is cobbled together from smaller parts that could easily have formed by chance, and then been retained for their function. | <urn:uuid:7f8cc92b-0637-4575-af57-d1f46a6f1a0e> | 3.40625 | 528 | Personal Blog | Science & Tech. | 54.954503 |
Here is a quick guide to doing problems involving the work energy theorem, to help you do your physics homework or assignment:
The work energy theorem states that the work done is equal to the change in kinetic energy:
where the kinetic energy is:
1. On a frozen pond, a 10-kg sled is given a kick that imparts to it an initial speed of = 2.0 m/s. The coefficient of kinetic friction between sled and ice is = 0.10. Use the work-energy theorem to find the distance the sled moves before coming to rest.
In this case, the work done by friction is equal to the change in kinetic energy (work energy theorem).
and since = 0,
2. You are given a uniform flexible chain whose mass is 5 kg and length is 5m, and a small frictionless pulley whose circumference is negligible compares to the length of the chain. Initially the chain is hung over the pulley with nearly equal lengths on both sides, but just unequal enough so that the unstable equilibrium condition will let the chain start to move. After some time, the longer end of the chain is a distance down from the pulley's axle. Find the acceleration of the chain when the chain is at this position. Find the velocity of the of the chain when
and the linear density of the chain is,
the mass of the left side of the pulley is,
and the mass of the right side of the pulley is,
and using Newton's laws on the left side of the pulley,
and on the right side of the pulley,
adding these equations gives,
and solving for a,
hence the acceleration of the chain at this position is 5.88 m/s2
to find the velocity at this point, we will use the work energy theorem to equate kinetic and potential energies of the chain.
The change in kinetic energy is,
the initial position of the chain nearly half hanging on both sides, then the entire chain goes to one side and therefore
and , and the chains center of mass is,
and the change in potential energy is,
finally from the conservation of energy, | <urn:uuid:2972d339-dcfc-4c84-a514-443388ee4fd3> | 4.40625 | 446 | Tutorial | Science & Tech. | 55.747936 |
One of the most important factors in building high-performance, scalable Web applications is the ability to store items, whether data objects, pages, or parts of a page, in memory the initial time they are requested. You can cache, or store, these items on the Web server or other software in the request stream, such as the proxy server or browser. This allows you to avoid recreating information that satisfied a previous request, particularly information that demands significant processor time or other resources. ASP.NET caching allows you to use a number of techniques to store page output or application data across HTTP requests and reuse it.
ASP.NET provides two types of caching that you can use to create high-performance Web applications. The first is output caching, which allows you to store dynamic page and user control responses on any HTTP 1.1 cache-capable device in the output stream, from the originating server to the requesting browser. On subsequent requests, the page or user control code is not executed; the cached output is used to satisfy the request. The second type of caching is application data caching, which you can use to programmatically store arbitrary objects, such as application data, in server memory so that your application can save the time and resources it takes to recreate them. | <urn:uuid:8917e9f8-9f3a-4eb2-aa6f-164fa9cf1f87> | 2.8125 | 256 | Documentation | Software Dev. | 35.617388 |
Far Side of the Moon
Happy Thanksgiving to the US!
Despite uncertainties in budgets and the world, work is continuing on the Orion Crew Exploration Vehicle. On December 14 Orion will be displayed at the Michoud Assembly Facility to mark completion of the Ground Test Article. Congress has approved funding for a Heavy Lift Launch Vehicle to boost Orion beyond LEO. Both a CEV and booster would be needed to finally get beyond Low Earth Orbit.
Lockheed-Martin, prime contractor for Orion, is still thinking of missions using Orion's unique capabilities. Previously they proposed using two docked Orions for an asteroid mission dubbed "Plymouth Rock." This week they proposed a mission to Lagrangian Point L2, on the far side of the Moon. A crew at L2 would send robotic probes to the surface, exploring the far side and poles. L2 is also a point coveted by Space colony enthusiasts, who would use it as a staging area for lunar materials. The far side of the Moon is a great location for radio astronomy, being protected by the Moon's bulk from Earth radio noise.
Another possible destination is the Earth-Sun L2 point, 1.5 million km from Earth. This is the future location of the troubled James Webb Space Telescope. JWST, like previous Space telescopes, will someday need servicing. Hopefully the JWST builders will include a docking capability with Orion. Rendezvous with JWST would be good training for a near-Earth asteroid.
FLORIDA TODAY reports an even more audacious plan. Their article claims that Lockheed wants to launch Orion unmanned atop a Delta IV EELV in 2013. In this mission Orion would orbit to 8000 km altitude and test its performance in the deep Space environment. Controllers on Earth would test the spacecraft's stability and control. The test would include reentry and water landing off Southern California. If successful, this would make a human asteroid mission possible by 2015. The article doesn't mention that a heavy lift booster would still be required to reach an asteroid.
High Earth orbit, the lunar farside or Sun-Earth L2 point are possible stepping-stones to an asteroid mission. The trip to a near-Earth asteroid could put a crew in Space for months. In turn an asteroid mission would be training for a mission to Phobos or Deimos. With the right steps, Orion and a Heavy Lift Launcher could send crews on the way to Mars soon.
Check out the latest Carnival of space! | <urn:uuid:63301e07-1499-4cb7-bc08-40ac88a0c46b> | 2.734375 | 505 | Personal Blog | Science & Tech. | 60.619398 |
In an article yesterday in the Guardian UK, the paper reports that Canadian provincial governments and aboriginal leaders have set aside vast amounts of coniferous woods, wetlands and peats, and the conservation bans logging, mining and oil drilling on an area twice the size of California.
The article mentions how the move is somewhat an anomaly for Canada, as it has been accused internationally as being a pariah and sabotaging the climate talks.
Forests (or lack of them) play an important role in climate change - deforestation produces about 20% of the global greenhouse gas emissions.
Canada's 1.3bn acres of boreal forest store the equivalent of 27 years' worth of current global greenhouse gas emissions, a Greenpeace study found. The destruction of those forests, scientists warn, would be like setting off a massive "carbon bomb" because of the sudden release of emissions. | <urn:uuid:6a643445-c5f4-42da-a32c-ab2abd61dd41> | 2.703125 | 175 | Personal Blog | Science & Tech. | 32.375635 |
Neighbour-Sensing model is the proposed hypothesis on how forms and shapes arise in the world of fungi.Audrius Meskauskas and David Moore in 2004.
The hypothesis suggests that each hypha (thread) in the fungal mycelium generates certain abstract field that (like the known physical fields) decreases with the distance. For instance, to distribute the hypha more evenly, the hyphal tips should avoid each other and threads in general. It is possible to rephrase this as "hypha generate scalar field that hyphal tips to avoid". When hypha follow this rule they form round ball with the close to uniform density inside. Even such a simple structure does not form as a result of the purely random branching and growth. The exact nature of the field may be important by itself but knowing it is not necessary for building the model. It is similar to the case of the harmonic oscillator where the same equations also describe processes that appear completely different (spring, pendulum and electric circuit).
The first truly interesting shape emerges after adding the rule that the tips try to preserve certain (for instance, 45 degree) orientation in the field of the Earth gravity. "Avoid tips and threads" plus "try to keep 45 degree orientation" together results a cone that is largely an empty inside and quite similar to some most primitive fruit bodies.
Chord production is possible after assuming the existence of the vector fields that are parallel to the vector of the hyphal threads. This looks like quite a big assumption, however researchers have observed the similarly oriented electric currents in hyphal surroundings. These currents enter or exit the hyphal tip and run in parallel to the rest of the thread, gradually entering it back at more basal phase. If such current can orient the growth direction of other tips ("parallel tropism"), all numerous tips in mycelia at the end turn in a or at most several alternative directions, building something that looks like a twisted wire rope. This "rope" can get more dense (and similar to the real chord) if we additionally add a weak positive attraction that presses the tips stronger together. Fungi use chords to transfer food resources over larger distance, or to spread to the new areas of growth, and also stems of the usual mushrooms look quite a bit similar.
It is also easy to make a colony "flat" by introducing tropism toward horizontal plane. This allows to compare the simulated morphology with the actual morphology observed in Petri dishes, where fungi mostly grow on the surface. While flat, the colony stays three dimensional: crossing hypha do not go directly through each other, resulting more realistic picture than in simple two dimensional models tried in the past.
The Neighbour-Sensing model explains how various fungal structures may arise without supposing any kind of the growth regulating hormones. These hormones, playing important role in plant and animal development, cannot be found in fungi.
Interestingly, it is possible to find some parallels between neighbor sensing model and mathematical models of flock. Flock algorithms also frequently contain components of the positive and negative attraction to the neighbor (responsible for the forming of the flock that has stable density) and desire to fly same direction as other members of the flock (similar to the parallel tropism). The main difference is that flock equations rely on the "mass center" of the flock, assuming than birds (or other creatures) can easily determine it. Fungal tips have no vision and unlikely to be capable to determine such center precisely, so the model instead assumes that they only sense the closest neighbours, and the capability to sense rapidly declines with the distance. | <urn:uuid:6d71eca8-19d8-4b60-b6ca-4bb6d0f69643> | 3.296875 | 733 | Knowledge Article | Science & Tech. | 33.372873 |
Science Fair Project Encyclopedia
In mathematics, a Diophantine equation is an equation between two polynomials with integer coefficients with any number of unknowns. A Diophantine problem is given as a Diophantine equation, whose solutions are the possible assignments of integers for the unknowns for which the equation is satisfied.
The word Diophantine refers to the Greek mathematician of the third century A.D., Diophantus of Alexandria, who made a study of such equations and was one of the first mathematicians to introduce symbolism into algebra. The mathematical study of Diophantine problems Diophantus initiated is now called Diophantine analysis.
A linear Diophantine equation is an equation between two sums of monomials of degree zero or one.
Examples of Diophantine equations
- ax + by = 1: See Bézout's identity; this is a linear Diophantine.
- xn + yn = zn: For n = 2 there are many solutions (x,y,z), the Pythagorean triples. For larger values of n, Fermat's last theorem states that no positive integer solutions x, y, z satisfying the above equation exist.
- x2 - n y2 = 1: (Pell's equation) which is named, mistakenly, after the English mathematician John Pell. It was studied by Fermat.
- , where and : These are the Thue equations, and are, in general, solvable.
The questions asked in Diophantine analysis include:
- Are there any solutions?
- Are there any solutions beyond some that are easily found by inspection?
- Are there finitely or infinitely many solutions?
- Can all solutions be found, in theory?
- Can one in practice compute a full list of solutions?
Hilbert's tenth problem
These traditional problems often lay unsolved for centuries, and mathematicians gradually came to understand their depth (in some cases), rather than treat them as puzzles. In 1900, in recognition of their depth, Hilbert proposed the solvability of all Diophantine problems as the tenth of his celebrated problems. In 1970, a novel result in mathematical logic known as Matiyasevich's theorem settled the problem negatively: in general Diophantine problems are unsolvable.
The point of view of Diophantine geometry, which is the application of algebraic geometry techniques in this field, has continued to grow as a result; since treating arbitrary equations is a dead end, attention turns to equations also having a geometric meaning.
The field of Diophantine approximation deals with the cases of Diophantine inequalities: variables are still supposed to be integral, but some coefficients may be irrational numbers, and the equality sign is replaced by upper and lower bounds.
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details | <urn:uuid:74a03c78-2beb-47b3-bcdb-8c8c80cf1e4b> | 3.734375 | 603 | Knowledge Article | Science & Tech. | 32.390398 |
Looking ahead to the Moon's shadow
When will you next be able to see the Moon block the Sun?
May 24, 2005
|Curious where the next 5 years' total solar eclipses will occur? How about the next 20 years'? Maybe one's coming to your locale or you'd like to experience the Moon's shadow in a foreign land. Fred Espenak has created a World Atlas of Solar Eclipse Paths spanning 5 millennia, from 2000 B.C. to 3000 A.D.|
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Dr. David Sibeck explains the instruments on the twin Van Allen Probes (formerly the Radiation Belt Storm Probes, RBSP). The Van Allen Probes will explore the Van Allen Radiation Belts in the Earth's magnetosphere. The charged particles in these regions can be hazardous to both spacecraft and astronauts. The mission also will allow researchers to understand fundamental radiation and particle acceleration processes throughout the universe.
Van Allen Probes - The Instruments WWW.GOODNEWS.WShttp://goodnews.ws/ | <urn:uuid:ad115fc6-7df9-4ceb-9c95-4ff0f3909c56> | 2.96875 | 105 | Truncated | Science & Tech. | 48.029342 |
Sep 26, 2005, 9:37 PM
Post #3 of 3
Copy of an article I wrote several years ago - relevant part highlighted in bold:
MEXICO'S ORANGE-COLORED PARASITIC PLANTS
There are numerous flowering parasitic plants in Mexico. Parasitic plants are those which live off the host plant and ultimately kill them, as opposed to epiphytes which live on them with no deleterious effects. Two genera of parasitic plants are particularly common and distinctive. Both are bright orange in color, and both can be seen in the vicinity of Lake Chapala.
The first is Cuscuta, also known as "dodders", "angel's hair", "devil's twine', and in Spanish, "zacatlascale". This is technically a holoparasite, incapable of photosynthesis, with no chlorophyll and no leaves. Its orange or yellowish strands, appropriately called "fideos" (spaghetti) in Costa Rica, can total more than 500 meters from a single seed. It is absolutely voracious, growing on anything. Wasps, bees and ants help to pollinate its flowers. It flowers virtually year round and is a parasite par excellence. It is used both as a source of dyes and in traditional medicine. Cuscuta is often evident either hanging from tree branches or simply decorating and mercilessly strangling roadside verges like some discarded seamstress's orange thread.
The other large genus of parasites is Phoradendron. This genus, the Mexican mistletoe, has many species. It is not the same as the evergreen European mistletoe with its white berries that was used in the ceremonies and rituals of the ancient Druids or, that in Norse mythology, was used for the dart that killed the god Baldur. It is still common in England to see the leaves and berries of Viscum album, the European mistletoe, hung in some prominent position at Christmastime to ward off evil spirits. Its presence is considered particularly propitious to lovers who kiss beneath it...
Of the Mexican mistletoes, some are herbaceous; others are vine-like, even treelike. Their leaves and flowers vary but several have tubular orange flowers growing wherever there is sufficient light. Phoradendron species are "hemiparasites", meaning that they are capable of some photosynthesis and have green leaves, unlike Cuscuta. Various birds including thrushes and tanagers feed heavily on mistletoe berries. Their sticky droppings deposited on branches contain the seeds which give rise to future mistletoe plants. Phoradendron flowers are well adapted to pollination by hummingbirds, though bees and other insects also help.
One of these mistletoes, locally called "Mal Ojo" (Evil Eye), is very much in evidence at present in the Chapala area. Left to its own devices, it will quickly kill its host trees. It is so prolific that it seems in many cases that the whole tree is in flower; unfortunately, it is not the tree's flowers that are such a dramatic orange in color but the parasite's.
There have been few ecological studies of the role played by parasitic plants in their ecosystems, and one author, L.D. Gomez, wryly observed that the study of this "somewhat esoteric assembly of bearded angels, witchweeds, diabolical entanglements, and strangling spaghetti, should best be attempted with bell, book and candle at hand."
Copyright, 1997 Tony Burton. All rights reserved. | <urn:uuid:1ea8c766-a0d2-4d7b-9052-34483e256b57> | 3.15625 | 745 | Comment Section | Science & Tech. | 38.859773 |
The Lotus Effect describes water droplets rolling off leaf surfaces, removing dirt and contaminants in the process. This phenomenon can also be seen in the more common nasturtium. Scanning electron microscope images show that nasturtium leaves are covered by waxy nanocrystal bundles. The uneven surface created by these tiny structures traps air between water and leaf, causing the water to roll off. Research on such nanoscale effects has inspired revolutionary new materials, including water- and stain-resistant fabrics.
Ann Marshall, Stanford University
The wax nanocrystal bundles covering the leaf are each about 1-2 µm wide.
This image was created by another institution, not the NISE Network. This image is available to NISE Network member organizations for non-profit educational use only. Uses may include but are not limited to reproduction and distribution of copies, creation of derivative works, and combination with other assets to create exhibitions, programs, publications, research, and Web sites. Minimum credit required. | <urn:uuid:649ad1ea-11a6-4f00-a31a-0e893b319708> | 3.546875 | 202 | Knowledge Article | Science & Tech. | 22.885615 |
1 GROUCHO MARX
Physicists worry about what they call the Groucho Marx effectthat any universe simple enough to be understood is too simple to produce a mind capable of understanding it. The discovery of the Higgs boson right where physicists were looking for it is a great sign that the universe isn't too complicated for us to understand after all. "It's a new clue to the big bang," says Neil Turok, director of Canada's Perimeter Institute for Theoretical Physics. "It gives us hope that we can really describe what was going on at that time."
2 IMPERFECT PREDICTIONS
What's most exciting for young physicists isn't what the predictions got rightit's what they got wrong. Early indications suggest that the Higgs boson isn't behaving quite as predicted when it decays into other particles at the end of its ultrashort lifetime. So far, it's decaying into photons more often than expected and into other particles less often. One possible explanation: The Higgs itself is a composite particle made of smaller particles, a prospect that could help to explain the mysterious dark matter that permeates the universe.
3 TECHNOLOGIES TBD
Even Peter Higgs, the 83-year-old physicist who helped predict the new particle in the 1960s, was stumped when asked about the new discovery's practical applications. "I have no idea," he admitted. That doesn't mean there won't be any, Brookhaven physicist Howard Gordon says: "When Einstein proposed relativity, no one thought of its application to GPS." Higgs's discovery sheds light on the energy stored in the fabric of spaceand gives us a chance to harness it. | <urn:uuid:9b8dacd7-b115-490f-a8ff-a6a8adcc925c> | 2.8125 | 348 | Truncated | Science & Tech. | 46.781304 |
Wild Things: Life as We Know It
Flamingos, T. rex Tails, Burmese monkeys and more...
- By Amanda Bensen, T.A. Frail, Megan Gambino, Jess Righthand and Sarah Zielinski
- Smithsonian magazine, January 2011
Liverworts are the most ancient plant group (Jan-Peter Frahm)
Plants that greened the earth 400 million years ago probably needed help. In experiments with liverworts, the most ancient plant group, scientists in Britain and Australia found that fungi may have provided nutrients to the plants as they spread across the continents.
Learn more about liverwort at the Encyclopedia of Life.
"Greater flamingos Phoenicopterus roseus use uropygial secretions as make-up," Juan A. Amat et al., Behavioral Ecology and Sociobiology, October 23, 2010
"An indigenous religious ritual selects for resistance to a toxicant in a livebearing fish," M. Tobler et al., Biology Letters, September 8, 2010
"Mutualistic mycorrhiza-like symbiosis in the most ancient group of land plants," Claire P. Humphreys et al., Nature Communications, November 2, 2010
"A New Species of Snub-Nosed Monkey, Genus Rhinopithecus Milne-Edwards, 1872 (Primates, Colobinae), From Northern Kachin State, Northeastern Myanmar," Thomas Geissmann et al., American Journal of Primatology, October 27, 2010
"The Tail of Tyrannosaurus: Reassessing the Size and Locomotive Importance of the M. caudofemoralis in Non-Avian Theropods," W. Scott Persons IV and Philip J. Currie, The Anatomical Record, November 12, 2010 | <urn:uuid:e368bfa6-aa35-497f-bf8d-74169be7f22d> | 3.375 | 384 | Content Listing | Science & Tech. | 43.552599 |
It is important to understand what part of the year, and what time of the day, severe weather is most likely. Those should be the times when your severe weather awareness is highest, as it is when you are most likely to be adversely impacted. Bear in mind though that tornadoes and severe weather can occur at any time of the year, day or night.
The NWS Norman's "Storm Spotter Resource Center" has a comprehensive severe weather climatology page that includes useful links and interesting facts. You also may want to visit the following links:
In Oklahoma and North Texas, tornadoes can happen at any time of the year. While we think of tornado season as being from mid March through mid June, we can see storms in any month. Remember that storms don't have a calendar, and don't care what month it is. As long as the right conditions come together, tornadoes can happen in December or August as easily as they can in April. A tornado has been recorded in Oklahoma in every month of the year.
For example, on January 25, 1967, four tornadoes occurred in the state of Oklahoma. Three of those tornadoes were rated an F2 on the Fujita Scale. Almost exactly ten years earlier, four tornadoes occurred on January 21-22, 1957 in Eastern Oklahoma. Two were rated an F2 and one was rated an F4 on the Fujita Scale.
Most tornadoes occur between 3 pm and 9 pm. But we can also have tornadoes after dark, which adds to the danger, the need to be prepared, and the need to have a plan to be safe. | <urn:uuid:b4857f36-3211-48ee-84d8-940d7c978c88> | 3.6875 | 332 | Knowledge Article | Science & Tech. | 58.806826 |
by T. Peterson, Ph.D.
(the following text excerpt is taken from:
The Creator's Window -Viewing Global Change,
Universal timelines, & The Promise, © 2000)
Many scientists say time is growing short. You do not escape this reality by ignorance. Everyone must pause to seriously consider the nature and magnitude of recent or imminent climate changes. This change is something to which you are a part! Your daily activity defines a personal connection to this problem!
I am emotionally moved as I watch conservative members of science speak passionately about change. The facts make their voices quiver. Humans now live in a most unusual time. For the present, I ask you to examine the vista of change in our physical world. Let us briefly examine present day change in relation to the Earths climate. Later on, many of these topics reappear and contribute to another aspect of the windows concluding panoramic historical view.
When sunlight enters the atmosphere, solar energy hitting Earth is either absorbed or reflected. Some atmospheric gasescalled greenhouse gasesabsorb reflected energy (trapped as heat) that would otherwise escape to outer space. The process works like panes of glass that trap heat within the enclosure of a greenhouse. In this age of information, the public readily associates increasing atmospheric carbon dioxide (CO2) concentration with global warming. Combustion of wood and fossil fuelscoal, oil, or natural gasfor industry, transportation, electricity, heat, etc., creates the CO2 that is a major force altering the worlds atmospheric composition (see Figure 1). The projected result of this change is demonstrated by computer models of the enhanced greenhouse effect that anticipate a significant net increase in the average global temperature, from 1.5 to 4.5°C, by the year 2050.
Many in the present generation will live to see consequences ascribed to global warming. For example, little change in CO2 levels occurred prior to the industrial revolution, but present change is dramatic, with a 30% increase from 1850 to 1980. Figure 1 illustrates there is an unmistakable steady upward trend (Average Value). Remarkably this process has a momentum of its own and CO2 levels continued to increase even when fossil fuel use was curtailed in the 80s (compare Figures 1 & 4). Conceivably, fires related to deforestation and processes other than fossil fuel use also contribute to CO2 rise. Here, human activity causes global change due to one specific factor. Atmospheric methane also acts as a highly efficient greenhouse gas by trapping 25% of the atmospheres heat energy. Sources for this gas include termites, cows, wetlands, garbage dumps, and industrial operations. Overall, the longer extra CO2 resides in the atmosphere the more heat is gained by Earth. The increased CO2 represents a driving force because, over time, the greenhouse effect alters weather patterns, rainfall distribution, growing seasons, and threatens to melt glaciers and polar ice capsresulting in sea level rise and other shocks to the environment and Earths inhabitants.
Figure 1: Global Carbon Dioxide Concentration. Seasonal measurements, made at Hawaiis Mauna Loa observatory, vary throughout the year as represented by the short segment labeled Seasonal Variation (e.g. 1964 through 1966). The variation corresponds to absorption of carbon dioxide by plants during growing seasons and net increases during the remainder of the year. Overall, the global trend is a steady upward rise in atmospheric carbon dioxide concentration, which is represented by the line labeled Average Value.
At this point some statistics help to paint a larger picture. For example, the US. population represents only 4.5% of the worlds total, yet this one nation produces 25% of the global CO2 emissions. Each year, for every person in the US., over 13,227.6 pounds of CO2 are put in the atmosphere because of affluent life styles. Every time I turn on a light, start the car, touch the thermostat, I contribute to a global problem. Citizens of the worlds industrial countries use the most fossil fuel and produce the highest emissions of greenhouse gases. According to 1987 estimates, each year the world community liberates over 6 billion metric tons of CO2 to the atmosphere (over 13,000,000,000,000 orin scientific notation1.3 x 1011 pounds).
The numbers only grow because consumption of fossil fuel and CO2 emissions rise further as other peoplesespecially the multitudes in developing regionsstrive to obtain the US. standard of living. Population growth means driving forces increase, not lessen, with time. Future global projections indicate an additional 75% increase in CO2 occurs as humanity approaches the middle of the next century, 50 to 60 years away. Earths atmospheric CO2 levels will be two-fold greater in 2050 compared to 1850. Undeniably humanity has changed conditions on Earthand this doubling of CO2 appears within the brief span of several human life timessince the days when Mr. Thoreau wrote of his experience at Walden Pond.
Scientific journals and newspapers describe how chloro-fluro-carbon (CFC) compounds degrade the naturally occurring ozone layer in the upper atmosphere. There, ozone serves as a solar filter absorbing harmful ultraviolet light (UV). The scientific community was first alarmed by enlarging ozone holes over Antarctica and Australia, but now global concerns grow with evidence for holes appearing over the northern hemisphere.
Will this problem go away soon? One alarming possibility, a warning raised by concerned scientists, indicates present amounts of atmospheric CFCs are sufficient to degrade stratospheric ozone for the next 100 years (SXi 90). Simply banning use of CFCs does not end the immediate problem.
Without the ozone barrier humans face increased rates of eye damage, skin cancers, animal immune disorders, and damage to agricultural crops. The consequence of high UV exposure for all of Earths life forms, from the simplest marine life to human beings, is a topic scientists continue to explore. This theme resurfaces later, in Part Four, along with other environmental penalties humanity is destined to seeespecially in light of the prospect that one day soon any exposure to the Sun may present a severe health risk.
Atmospheric chemistry mirrors change through perplexing relationships. While ozone is lost to the upper atmosphere, human activity causes increased ozone production in the lower atmosphere. On the Earths surface, automobile and industrial pollutants cause formation of ozone, nitrous oxide, and hydrocarbons producing pollution called smog (smoke + fog). While beneficial up above, down below ozone is harmful to native plants and agricultural crops. This degrades natural ecosystems and reduces farm yields. City smog poses a hazard to human health and by its chemical activity damages architectural structures.
Less obvious are emissions of sulfur and nitrogen oxides, released from power plant and industrial smoke stacks, that are the source of acid rain. This acid deposition has a long reach. Pollutants released to the atmosphere move with clouds producing rain which later falls on distant cities and forests. The acidity flushes nutrients from soils, diminishes or eliminates native fish and water fowl populations, and slowly weakens trees and plant life which eventually die from disease or soil infertility. And this is part of the global change I see near my summer home.
As coal and automobile use increases, the effects of acid rain spread over larger geographic areas. For example, increasing coal combustion to generate electricity for Chinas expanding industrial base correspondingly produces more acid rainand coincidentally dramatic increases in CO2 emissions, too. China has made an effort to use coal efficiently, but Chinas immense work force needs electric power. Economically, alternate fuels are difficult to justify when China holds the worlds largest known coal deposits.
Consequences of Climate Change
Models and data used to predict climate change differmodel to model, lab to lableading to general conclusions about the Earths future temperatures, light quality, and rainfall distribution. No one expects totally uniform change. Thus, global warming may manifest itself as generally warmer night temperatures in some places and extreme local cooling elsewhere. Change will appear in regional episodesmuch like hurricane intensities that in the mid-90s rose to historic heights or as in 1993 when massive floods covered the US. midwest and simultaneously drought dried the southeast. To our thinking, the severest, most graphic evidence for climate change appears after crops fail, when food prices fluctuate, and as live stock inventories dwindle. When does climate change become a personal reality? I can imagine your reaction if daily food expenses threaten to exceed one's daily wage. Is this possible? Yesfor this is one of a number of global circumstances documented in this books timeline conclusion.
Figure 2: Global Temperature Change. This plot of temperature over time represents a world-wide summary. Raw temperature data, collected on a regional basis, only indicates seasonal change in a single geographic area A net change in global surface temperature is shown here relative to a zero-base line. This model, among others, argues in favor of a net increase in global temperatures over recent time.
Not all change is negative. Loss of favorable conditions in one locality suggest improvement elsewhere. My concern lies in the pace of change. As indicated by Figure 2, real temperature change occurred during the 1900s. The expected alteration in global weather patterns may already contribute to expansion of deserts and deforestation. Elsewhere, rainforest destruction in the Amazon brings drought to the affected area. In the balance, waste regions on the planet turning hospitable to vegetation take decades or centuries to form stable grasslands and forests. Humans can plant trees for reforestation, but thereafter must hope for success and prolonged stable climatic conditions. There is no quick fix for these global issues. The scientific community calls for measures to slow rates of change in hopes of reaching some new level of environmental stability. Critics of this approach recognize most humans fail to perceive a problem, day to day, and many affluent beings are unwilling to alter their life style to achieve these objectives.
How are you to understand seemingly imperceptibleyear to yearclimate changes? Figure 2 gives some clues. While the debate about global models rages on, I watch climate change follow a timeline. The graph describes the meandering nature of yearly average surface temperatures on Earth. Overall there is a net increase in temperature. From 1850 to the present, the change in temperature is a rise of approximately 0.8 °C. Walden Pond is a warmer place now than in Henrys day. If the trend is upward, increased CO2 represents a catalyst for a dramatic increase in global temperature. At no previous time have humans lived with such high levels of CO2. If the Earth and atmosphere hit some unforeseen threshold for dramatic climate change, events that follow will be absolutely beyond human control.
I have only mentioned several aspects of climate change. Pollution, temperature, cloud patterns, acidity, quality of light, distribution of rain and related factors influence the quality of life on Earth. My appreciation for a larger process at work recognizes that human-driven change influences the worlds plant and animal lifeespecially where native habitats are altered beyond existence. Where does one live without their house? Where would humanity be without a habitable planet?
This is just one of many panes in the WindowView. This is a fraction of the process identified earlier within the section entitled 'Convergence.' Keep exploring the view, visit our page titled 'Experience WindowView' to see how global changes are part of a larger holistic paradigm which is the reason behind assembling this cyber-place. Putting the picture together helps to envision humanity's direction along the dimension of time.A copy of this text with footnotes and a complete listing of references used in writing this text can be obtained by downloading the chapters and reference list for the Creator's Window. References that appear as ''(SXi #)'' signify the page number from Sigma Xi's publication related to a 1991 forum on global change (see reference list for the Creator's Window for a complete citation of this work).
The importance to global change is in looking at how social, biological, and physical sciences all reveal data and signs for more ominous changes in the near future. This is change in every aspect of human and earthly affairs ... globally. The Window looks further to see change as a backdrop to a biblical timeline. Driving forces for change force us to ask the most important questions about our true origin, who we are, why we are here, and what the Scriptures tell us about the future. Change forces us to look deeper to face choice or crisis. Life is an opportunity to look for the answers. | <urn:uuid:0c67c133-5bd7-4f37-8afc-9595c6e2b347> | 2.953125 | 2,554 | Knowledge Article | Science & Tech. | 33.980759 |
NINO3.4 sea surface temperature anomalies are a commonly used metric for the frequency, strength and duration of El Niño and La Niña events. For the week centered on Wednesday December 12, 2012, they’re close to zero—at about 0.02 deg C. As has been apparent for a few weeks, it looks like this year’s ENSO event will be a La Nada.
Global sea surface temperature anomalies appear to have responded quite quickly to the stronger El Niño conditions earlier this year. Then they cooled as abruptly in response to its decay. Now they’re around 0.2 deg C. Will global sea surface temperatures make a secondary rebound as they had during the 2009/10 El Niño, or will they hover, varying with seasonal and weather noise, waiting for the next El Niño or La Niña? And what will it be, another La Nada–or an El Niño or La Niña?
INTERESTED IN LEARNING MORE ABOUT THE EL NIÑO AND LA NIÑA AND THEIR LONG-TERM EFFECTS ON GLOBAL SEA SURFACE TEMPERATURES?
Why should you be interested? Sea surface temperature records indicate El Niño and La Niña events are responsible for the warming of global sea surface temperature anomalies over the past 30 years, not manmade greenhouse gases. I’ve searched sea surface temperature records for more than 4 years, and I can find no evidence of an anthropogenic greenhouse gas signal. That is, the warming of the global oceans has been caused by Mother Nature, not anthropogenic greenhouse gases.
I’ve recently published my e-book (pdf) about the phenomena called El Niño and La Niña. It’s titled Who Turned on the Heat? with the subtitle The Unsuspected Global Warming Culprit, El Niño Southern Oscillation. It is intended for persons (with or without technical backgrounds) interested in learning about El Niño and La Niña events and in understanding the natural causes of the warming of our global oceans for the past 30 years. Because land surface air temperatures simply exaggerate the natural warming of the global oceans over annual and multidecadal time periods, the vast majority of the warming taking place on land is natural as well. The book is the product of years of research of the satellite-era sea surface temperature data that’s available to the public via the internet. It presents how the data accounts for its warming—and there are no indications the warming was caused by manmade greenhouse gases. None at all.
Who Turned on the Heat?was introduced in the blog post Everything You Ever Wanted to Know about El Niño and La Niña… …Well Just about Everything. The Updated Free Preview includes the Table of Contents; the Introduction; the beginning of Section 1, with the cartoon-like illustrations; the discussion About the Cover; and the Closing. The book was updated recently to correct a few typos.
Please buy a copy. (Credit/Debit Card through PayPal. You do NOT need to open a PayPal account.). It’s only US$8.00.
For those who’d like a more detailed preview of Who Turned on the Heat?, see Parts 1 and 2 of the video series The Natural Warming of the Global Oceans. You may also be interested in the video Dear President Obama: A Video Memo about Climate Change.
The Sea Surface Temperature anomaly data used in this post is available through the NOAA NOMADS website: | <urn:uuid:4e125832-bfe5-48e0-8104-93d6ca15d879> | 3.296875 | 727 | Personal Blog | Science & Tech. | 51.018916 |
|- The Camera|
|- The Spectrographs|
|Details of the Data|
The SDSS survey collects data with modern, digital detectors. An enormous array of CCD detectors takes images, and a pair of spectrographs, fed by optical fibers, collects spectra.
The CCD Camera
The inner sanctum of the SDSS telescope contains what may be the most complex camera ever built. The camera includes 30 electronic light sensors called charge-coupled devices (CCDs) like the one at left, each two inches square. The CCDs are arranged five to a column, and scientists encase each column in a vacuum-sealed chamber. To enhance sensitivity, liquid nitrogen cools each chamber to -80 degrees Celsius.
Each CCD is made up of more than four million picture elements (pixels) that release
electrons when they absorb light. The electrons are then amplified into
electronic signals that can be digitized, recorded on tape and ultimately
fed into a computer. Each of the five rows of CCDs receives light through
a different colored filter, so each row records the brightness of objects in a
different color. A night of observing will produce up to 200 gigabytes of
data on a dozen tapes.
The drawing to the right shows a schematic view of the camera. Unlike a typical camera, this one doesn't snap a still picture. Instead, the telescope is parked in a given position, and as the earth rotates, the sky moves over the camera, from top to bottom. The electrons released by the incoming light are moved (or clocked) along the CCDs at the same rate that the sky moves over the camera, ensuring that the signal is always gathered from the same objects. When a moving electron hits the edge of a CCD, it is read out through amplifiers. This readout is done continuously, resulting in long, skinny strips of sky imaged in one observation. Because the CCDs have spaces between them, to make a full picture, the telescope must be moved a little bit, and a second, slightly offset strip is imaged. A pair of strips is then combined into a single stripe, which has no empty areas.
A spectrograph, a prism-like device that disperses light into many colors, measures
how much light objects emit at different wavelengths. This information, called
a "spectrum," can be used to analyze the distance, composition and age of
each celestial object. SDSS astronomers drill 640 holes in an aluminum plate, with
each hole corresponding to the position of a selected star, galaxy, or quasar.
Scientists plug the holes with optical fiber cables (right). The fibers
capture light from the 640 objects simultaneously and send it into the
two spectrographs. The spectrographs split the light form each object into
composite colors, and the resulting spectra are recorded using CCDs. Each
spectrum is measured from 3800Å (blue) to 9200Å (near infrared)
Because the light is split, four images are created for each spectroscopic
observation: both a red and blue image for spectrograph #1 and also
for spectrograph #2. The plug plates are placed at the focal plane of
the telescope, just like the CCD camera. On a good night, SDSS astronomers will use six
to nine plates, obtaining spectra for up to 5,000 objects!
The spectrograph will observe all galaxies seen by the imaging survey at magnitude
17.8 or brighter. The survey plans to obtain over a million galaxy spectra - thirty times
more than any presently available galaxy redshift survey. In addition to obtaining
galaxy spectra, the SDSS plans to target 100,000 quasar candidates (selected based on
their colors), tens of thousands of stars, and many other objects, such as
X-ray and radio sources. | <urn:uuid:a0bdf519-8ac6-492b-923d-9311919fe693> | 4.1875 | 830 | Knowledge Article | Science & Tech. | 47.331253 |
For some time, it has been known that communications towers pose a hazard for many species of birds. The problem is exacerbated when towers are placed in centers of migratory activity. Bird kills at towers tend to come from two causes. Sometimes birds will not see a portion of the tower, such as a guy wire or antenna. In other cases, birds are disoriented by a tower's lights and crash into the tower or the ground. The latter is a particular problem for nocturnal migrants.
Exact numbers of birds killed each year are difficult to determine because few towers are monitored. The Fish and Wildlife Service estimates 4-5 million on the basis of bodies recovered at a small sample of towers, but the number could well be much larger. At least 230 species are affected. Migrant songbirds are the primary victims of communication towers. This document (pdf) gives the top ten species killed.
- Red-eyed Vireo
- Tennessee Warbler
- Common Yellowthroat
- Bay-breasted Warbler
- American Redstart
- Blackpoll Warbler
- Black-and-White Warbler
- Philadelphia Vireo
- Swainson's Thrush
- Placement of new antennas on existing towers where possible rather than building new structures.
- Keeping tower height under 200 feet, to avoid the need for lighting, and using self-supported structures rather guy wires.
- Restricting towers within areas of major migratory activity.
- Limiting lighting to the FAA minimum and using white strobe lights instead of red lights.
For more information | <urn:uuid:4b02040a-f2f7-4b54-a8ee-873267af2ee3> | 3.546875 | 323 | Personal Blog | Science & Tech. | 44.635375 |
DistributionRead full entry
Range DescriptionThe two disjunct subspecies are separated by 130° of longitude and about 8,500 km.
C. c. commersonii - Falkland Islands / Islas Malvinas and the coastal waters of southern South America. On the Atlantic coast the northern limit is at approximately Península Valdés. The range extends south into Drake Passage (61°50'S) as far as the South Shetland Islands, well within the range of C. eutropia (Rice 1998) (C. eutropia is predominately coastal and rarely goes into deep water or far offshore). Single dolphins and groups of up to hundreds were sighted in the late 1980s and early 1990s along the northern coast of Tierra del Fuego (Goodall 1994). Although sightings in the northern parts of the range often are of small groups or solitary individuals, overall numbers and group sizes increase to the south. On the west coast of South America, the northernmost confirmed record is a sighting of five individuals off Cape Valentin (53°33’S, 79°25’W) (Sielfeld and Venegas 1978). Genetic population structure is being studied in Argentina, where two “ecological stocks” have been identified based on differences in parasite loads and patterns of prey consumption (Berón-Vera et al. 2001).
C. c. subsp. nova - Shallow coastal waters around all of the Îles Kerguélen in the southern Indian Ocean (Rice 1998; Robineau et al. 2007). No sightings or specimens have yet been reported from islands between South America and Kerguélen, such as Crozet, Heard, Amsterdam or St Paul (Goodall 1994). Dolphins of the Kerguelen Islands subspecies are most commonly sighted in the Golfe du Morbihan, on the eastern side of Kerguélen.
Recently, a sighting of a single individual south of Cape Town, in South African waters, was reported, although this should be considered extralimital (de Bruyns et al. 2006). There are also unsubstantiated reports of this species at South Georgia, but these have been rejected (Brown 1988). | <urn:uuid:82391923-d423-4e7a-87e7-7036a959ce06> | 2.78125 | 469 | Structured Data | Science & Tech. | 53.942314 |
[erlang-questions] Code generation (was NOOB)
Tue Sep 5 23:32:10 CEST 2006
Jay Nelson wrote:
> Bjorn clarified some optimization approaches:
> > We have considered improving the optimization, so that no list would
>> be built in case 2.
> Where case 2 was the line commented <2> below:
>> foo(X) ->
>> A = [do_something(E) || E <- X], % <1>
>> [do_other(E) || E <- X], % <2>
You must clarify what you mean is the exact difference between <1> and
<2>? Is it the explicit assignment to A? Or that the return value is
If it is the assignment then that is a very "sub-optimal" (to be nice)
way of ascertaining whether the return value is used. The compiler has
no difficult in finding out if the return value form the lc (the list)
is actually used so checking for as assignment is useless.
It should not cause any problems if the actual list was not built, just
as long as the code to build the list elements is executed for each
element-not-to-be. The code can contain side-effects or cause an error.
Actually, the only difference between <1> and <2> is that <1> calls
do_something on each element of X, while <2> calls do_other.
P.S. I think you should use code which builds a list when you want to
build a list, not for side-effects! But then again I am a purist.
More information about the erlang-questions | <urn:uuid:e72d1653-e050-48ed-8adb-f05062d94317> | 3.234375 | 365 | Comment Section | Software Dev. | 65.491562 |
A particular spring has a force constant of 2.5 X 103 N/m.
(a) How much work is done in stretching the initially-relaxed spring by 6.0 cm?
(b) How much more work is done in stretching the spring an additional 2.0 cm?
There are two (slightly) different ways to look at this problem. The first is to state that the work done on the spring is equal to the change in the spring potential energy:Originally Posted by Candy
The other is to consider that the work done is the integral of the force over the infinitesimal displacements:
which, of course, gives the same formula as above.
Either way you want to look at it:
a) The spring is initially relaxed, so it's at its equilibrium position x0 = 0 m.
The spring is stretched 0.060 m. So the final state of the spring has x = 0.060 m. (ALWAYS use m for this!) Thus:
= 4.5 J
b) We wish to find how much extra work is done, so use x0 = 0.060 m and x = 0.080 m.
= 3.5 J | <urn:uuid:a5d9354d-e854-4be6-bbd9-a4bcf27de023> | 2.953125 | 253 | Q&A Forum | Science & Tech. | 94.191842 |
Find a great variety of ways of asking questions which make 8.
What is the units digit for the number 123^(456) ?
Choose any 3 digits and make a 6 digit number by repeating the 3
digits in the same order (e.g. 594594). Explain why whatever digits
you choose the number will always be divisible by 7, 11 and 13. | <urn:uuid:8f1686e7-c48a-457c-bae2-e4fc022a2cf8> | 2.921875 | 80 | Q&A Forum | Science & Tech. | 86.951899 |
Giant Golden Mole - Chrysochloris trevelyani [now Chrysospalax trevelyani]
If there were ever a mammal worthy of being given the common name of “Blorp”, this would be it. But no, they get to be called the “giant golden mole”, despite not being all that giant, or all that golden. I’m still calling them Blorps.
These pudgers are ancient, mostly-desert-dwelling Gondwanan creatures which are remarkably well adapted to climates with significant thermal shifts. During times of extreme heat or cold, their bodies can go into a state of torpor, almost stalling their basal metabolism rate, and completely turning off their internal thermoregulation until the temperature returns to a more amicable range.
The family of golden moles, Chrysochloridae, is not related to the “true moles” (Talpidae), but get their common name from their similar appearance, which developed through convergent evolution. Most scientists agree that the golden moles are more closely related to hedgehogs and shrews than to true moles, though some theories group them with the tenrecs. Until full genetic profiles are established for the Insectivoridae, we probably won’t have a definitive answer.
Proceedings of the Zoological Society of London. 1875. | <urn:uuid:3e369b41-c752-4758-966b-8162c91a0564> | 3.359375 | 297 | Personal Blog | Science & Tech. | 32.247 |
Thermodynamics is a subsection of physics that deals with energy and its relationship with properties of matter. It is concerned with the different forms of energy and their transformation between one another. It provides the general laws that are the basis for energy conversion, transfer, and storage.
Systems, System Boundaries, Surroundings:
A thermodynamic system, or briefly a system, is a quantity of matter or a region in space chosen for a thermodynamic investigation. Some examples of systems are an amount of gas, a liquid and its vapor, a mixture of several liquids, a crystal or a power plant. The system is separated from the surroundings, the so-called environment, by a boundary (real or imaginary). The boundary is allowed to move during the process under investigation, e.g., during the expansion of a gas, and matter and energy may cross the boundary. Energy can cross a boundary with matter and in the form of heat transfer or work. The system with its boundary serves as a region with a barrier in which computations of energy conversion processes take place. Using an energy balance relationship (the first law of thermodynamics) applied to a system; energies that cross the system boundary (in or out), the changes in stored energy, and the properties of the system are linked. A system is called closed when mass is not allowed to cross the boundary, and open when mass crosses the system boundary. While the mass of a closed system always remains constant, the mass inside an open system may also remain constant when the total mass flow in and the total mass flow out are equal.
Description of States, Properties, and Thermodynamic Processes:
A system is characterized by physical properties, which can be given at any instant, for example, pressure, temperature, density, electrical conductivity, and refraction index. The state of a system is determined by the values of these properties. The transition of a system from one equilibrium state to another is called a change of state. The distinction between a closed and an open system corresponds to the distinction between a Lagrangian and an Eulerian reference system in fluid mechanics. In the Lagrangian reference system, which corresponds to the closed system, the fluid motion is examined by dividing the flow into small elements of constant mass and deriving the corresponding equations of motion. | <urn:uuid:8975d272-1127-44cd-a31b-ec2519968f30> | 3.609375 | 470 | Knowledge Article | Science & Tech. | 33.600226 |
here are many Java user interface toolkits. The most common, of course, are AWT and Swing, each of which has its advantages and drawbacks. Swing in particular, while it looks great, can be burdensome to develop and leads to large code footprints. As an example, Figure 1 shows a very simple Swing GUI developed with the excellent Oracle JDeveloper IDE.
Without any code to activate this GUI and respond to events such as the Button Click, Figure 1
already involves 114 lines of code, including the necessary imports. A snippet of this code is shown below, where you can see that four lines of code alone are needed to describe the button. This verbosity isn't the fault of the IDEit's just the way that AWT and Swing work, and this IDE uses components from these frameworks as appropriate.
button1.setBounds(new Rectangle(240, 55, 110, 25));
With Swing you also have the problem of the application logic and the UI description potentially being munged together. With careful work, these can be separated, but most of the time you will use an IDE, and IDEs generally munge the code together if you use their designers. Building a GUI without using a designer tends to be a lot of work, so you end up being stuck with an application where GUI layout and implementation tend to be merged together. Therefore, if you need to separate UI and implementation, you'll need a source management system and build process even for the simplest of projects, and you'll likely have to sort out a lot of the GUI details by hand.
|Figure 1. Swing GUI: This simple Java GUI (shown on the JDeveloper stage), developed with a Swing/AWT-based editor, requires a lot of code.|
XUI is an open-source project, available on the artistic license
that is intended to make GUI development clearer, cleaner, separated, and well modeled. Perhaps most importantly, it will dramatically reduce the amount of code necessary for Java GUIsand as any developer can tell you, the less code, the less chance of bugs. XUI may be downloaded from its home page
It isn't intended as a replacement
for the Swing and AWT frameworks, but instead it is a suite of supporting tools to make coding with these frameworks a lot easier. The best way to understand how it works is by example, so over the course of this article you'll use XUI to build some GUIs and gain an understanding of what it does for you.
|Author's Note: The artistic license is one of the lesser-known open source licenses. You can see the full license details at: http://www.opensource.org/licenses/artistic-license.php. It allows you to modify the source any way that you like as long as you don't redistribute the modified versions. Modifications should be folded into the main distribution instead (pending owner's approval of course). | <urn:uuid:f73625ce-ac51-4b76-bf99-b2fca5442107> | 2.859375 | 607 | Truncated | Software Dev. | 50.265369 |
2 Marine Research Plankton Survey Database
Plankton surveys and primarily, egg surveys, are another tool to
help fisheries scientists calculate biomass abundance [ Zeldis, J.
1993. The applicability of egg surveys for spawning stock biomass
estimation of snapper, orange roughy and hoki in New Zealand.
Bulletin of Marine Science 53(2) : 864-890 ]. The basic theory of
population estimates made from egg surveys is well known:
"If one can estimate the total production of eggs or larvae
of a stock, P, throughout a spawning season, and determine the mean
fecundity, F, of a mature female and the proportion of females in a
mature stock, K, then the total abundance of the mature stock
[Crossland, J. 1980. The number of snapper Chrysophrys auratus
(Forster), in the Hauraki Gulf, New Zealand, based on egg surveys in
1974-75 and 1975-76. Fisheries Research Bulletin No. 22 40p.]
Plankton surveys in a sample area can be conducted in a variety of
ways such as stratified, random, or grid stations and are often
carried out in conjunction with trawl surveys. The nets used are
varied in size and shape but all have very fine mesh They range from
a large Engels midwater trawl for rock lobster pureluii, to small
cylinder-code trawl nets, to vertically dropped plankton nets.
These surveys use a variety of egg production models (such as the:
"daily egg production method" (DEPM); the "annual egg
production method" (AEPM); and the "daily fecundity
reduction method" (DFRM)) for fish stock biomass calculation.
The DEPM estimates the adult spawning biomass from the ratio of
the daily production of planktonic eggs and the daily fecundity. The
latter is calculated using daily spawning frequency, average batch
fecundity, average female weight and sex ratio. The planktonic eggs
are caught during a plankton survey and the spawning frequency, batch
fecundity, and sex ratio are estimated using a trawl survey.
The DFRM estimates biomass of spawning females by dividing the
daily planktonic egg production in the survey area by the
weight-specific daily fecundity of females. Because it is a daily
method, there is the advantage that the DFRM does not need to cover
the entire spawning season. | <urn:uuid:917907aa-df06-4975-823e-7192464847c9> | 3.296875 | 532 | Knowledge Article | Science & Tech. | 41.309456 |
In this section, we discuss MPI's derived datatype mechanism. We also list MPI features not covered in this book.
In earlier sections of this chapter, MPI routines have been used to communicate simple datatypes, such as integers and reals, or arrays of these types. The final set of MPI functions that we describe implements derived types, a mechanism allowing noncontiguous data elements to be grouped together in a message. This mechanism permits us to avoid data copy operations. Without it, the sending of a row of a two-dimensional array stored by columns would require that these noncontiguous elements be copied into a buffer before being sent.
Figure 8.12: MPI derived datatype functions.
Three sets of functions are applied for manipulating derived types. Derived datatypes are constructed by applying constructor functions to simple or derived types; we describe three constructor functions MPI_TYPE_CONTIGUOUS, MPI_TYPE_VECTOR, and MPI_TYPE_INDEXED. The commit function, MPI_TYPE_COMMIT, must be applied to a derived type before it can be used in a communication operation. Finally, the free function, MPI_TYPE_FREE, should be applied to a derived type after use, in order to reclaim storage. These functions are summarized in Figure 8.12.
The constructor MPI_TYPE_CONTIGUOUS is used to define a type comprising one or more contiguous data elements. A call of the form MPI_TYPE_CONTIGUOUS(count, oldtype, newtype)
defines a derived type newtype comprising count consecutive occurrences of datatype oldtype. For example, the sequence of calls
call MPI_TYPE_CONTIGUOUS(10, MPI_REAL, tenrealtype, ierr) call MPI_TYPE_COMMIT(tenrealtype, ierr) call MPI_SEND(data, 1, tenrealtype, dest, tag, $ MPI_COMM_WORLD, ierr) CALL MPI_TYPE_FREE(tenrealtype, ierr)is equivalent to the following single call.
call MPI_SEND(data, 10, MPI_REAL, dest, tag, $ MPI_COMM_WORLD, ierr)Both code fragments send a sequence of ten contiguous real values at location data to process dest.
The constructor MPI_TYPE_VECTOR is used to define a type comprising one or more blocks of data elements separated by a constant stride in an array. A call of the form
MPI_TYPE_VECTOR(count, blocklen, stride, oldtype, newtype)
defines a derived type newtype comprising count consecutive blocks of data elements with datatype oldtype, with each block containing blocklen data elements, and the start of successive blocks separated by stride data elements. For example, the sequence of calls
float data; MPI_Datatype floattype; MPI_Type_vector(10, 1, 32, MPI_FLOAT, &floattype); MPI_Type_commit(&floattype); MPI_Send(data, 1, floattype, dest, tag, MPI_COMM_WORLD); MPI_Type_free(&floattype);is equivalent to the following code.
float data, buff; for (i=0; i<10; i++) buff[i] = data[i*32]; MPI_Send(buff, 10, MPI_FLOAT, dest, tag, MPI_COMM_WORLD);Both send ten floating-point numbers from locations data, data,..., data.
Program 8.8 uses derived types to communicate the north and south rows and the west and east columns of a Fortran array. As illustrated in Figure 8.13, a column of this array is stored in contiguous locations and can be accessed by using a contiguous derived type. On the other hand, row i of this array (comprising elements array( i ,1), ( i ,2), ... , ( i ,6)) is located in elements i , i +4, ..., i +20. As these elements are not stored in contiguous locations, a call to MPI_TYPE_VECTOR is used to define the appropriate type, rowtype.
Program 8.8 frees the derived types that it defines immediately after they are used. In practice, a type might be reused many times before being freed.
Figure 8.13: A finite difference grid. Areas to be sent to west, east, north, and south neighbors are highlighted.
The third constructor, MPI_TYPE_INDEXED, is used to define a type comprising one or more blocks of a primitive or previously defined datatype, where block lengths and the displacements between blocks are specified in arrays. A call of the form
MPI_TYPE_INDEXED(count, lengths, indices, oldtype, newtype)
defines a derived type newtype comprising count consecutive blocks of data elements with datatype oldtype, with block i having a displacement of indices( i ) data elements and containing lengths( i ) data elements.
In Example 8.4 and Program 8.6, we developed an implementation for a Fock matrix task that receives read requests containing the address of a single data value. A more realistic program might support messages comprising len/2 indices followed by len/2 block lengths. The MPI_TYPE_INDEXED constructor can then be used to return the required values, as follows.
call MPI_TYPE_INDEXED(len/2, inbuf(len/2+1), inbuf(1), $ MPI_INTEGER, focktype, ierr) call MPI_TYPE_COMMIT(focktype, ierr); call MPI_SEND(data, 1, focktype, source, MPI_COMM_WORLD, ierr) call MPI_TYPE_FREE(focktype, ierr)
An alternative approach that does not use the constructor is to accumulate the values that are to be returned in a buffer. The relative efficiency of the two approaches depends on several factors, including the amount of data to be transferred and the capabilities of the computer used to execute the program.
For simplicity, we have focused on a subset of MPI in this chapter. Of necessity, numerous subtleties have been omitted in this brief description. Also, the following MPI features have not been covered.
© Copyright 1995 by Ian Foster | <urn:uuid:a47a6a1e-2f9d-4b47-b483-77af57a2fed5> | 3.21875 | 1,396 | Documentation | Software Dev. | 34.955679 |
What would a tram look like if it was whizzing by at near-light speed? In this animation, created by Antony Searle from the Australian National University, you can see how its appearance would be altered due to the weird effects of special relativity.
In the first sequence, you're behind a static camera as the tram speeds by and it appears to shrink. This is partly due to length contraction, the relativistic change in length that occurs along its direction of motion. But relativistic distortion also plays a role due to the tram's near-light speed and the time it takes for light to reach you.
In the second clip, the tram is hurtling towards you. It seems to approach faster than it recedes since light has less distance to travel as the tram comes towards you than when it moves away.
In the final scene, shadows behave strangely due to the finite speed of light. "The tram is moving so fast, it is effectively getting out of the way of its own shadow," writes Searle.
If you enjoyed this video, check out previous videos in our Seeing Relativity series, including a mind-bending tour of the solar system. | <urn:uuid:464cdbcd-8b10-4a19-835a-c3698ce4981b> | 3.796875 | 241 | Truncated | Science & Tech. | 58.060366 |
CREATE TABLE table [ (column [, ...] ) ] AS select_clause
The name of a new table to be created.
The name of a column. Multiple column names can be specified using a comma-delimited list of column names.
A valid query statement. Refer to SELECT for a description of the allowed syntax.
Refer to CREATE TABLE and SELECT for a summary of possible output messages.
CREATE TABLE AS enables a table to be created from the contents of an existing table. It is functionality equivalent to SELECT INTO, but with perhaps a more direct syntax. | <urn:uuid:18620abf-a135-4e18-b2b8-3b611d1ce407> | 2.828125 | 122 | Documentation | Software Dev. | 48.761259 |
The Wild Side
Alumnus protects endangered Texas animals
Pockets filled with bug bits—cicadas, actually—are what Omar Bocanegra’s mom found every week in her son’s laundry. Young Omar was fascinated by nature, and boys always bring treasures home in their pockets.
Being a city kid, Bocanegra’s wildlife specimens were limited. No deer roamed his Fort Worth neighborhood. “If you’re interested in wildlife in the city,” he explains, “your biggest variety is going to be insects.”
So it was. And so it remained, at least through college. When it came time to select a university and major, Bocanegra sought out someone who shared his fascination. He found UT Arlington biology Professor James Robinson, an expert in the evolutionary ecology of aquatic insects.
Under Dr. Robinson’s guidance, Bocanegra researched the desert firetail damselfly and went on to earn bachelor’s and master’s degrees in biology from UT Arlington. Over the years he built an extensive collection of damselfly specimens, including one that was the first to be identified in the United States.
Today he is a fish and wildlife biologist and coordinator of the Endangered Species Program in the U.S. Fish and Wildlife Service’s Arlington field office. He oversees efforts to preserve and restore 11 endangered or threatened species—including the black-capped vireo and whooping crane—in 112 North Texas counties.
Much of his work involves consulting with other agencies and landowners. “We educate landowners about changes they can make to protect a species, and at very little cost to themselves,” he says. “Small techniques in the way land is managed may easily help preserve a species.” | <urn:uuid:d4d8ccd4-50ce-4b11-bba4-b8b8d8455d87> | 2.921875 | 378 | Nonfiction Writing | Science & Tech. | 43.863483 |
Parse tree. Another name: derivation tree (DT). The result of grammatical analysis. The parse tree differs from the abstract syntactical tree in that it contains nodes for those syntactic rules which do not influence the program semantics. A classical example of such nodes is grouping parentheses, while grouping of operands in AST is explicitly defined by the tree structure.
In the open library VivaCore our company is developing, it is building the parse tree of the C/C++ code that takes place. It allows you to get some additional information to be used by static code analyzers included into PVS-Studio. | <urn:uuid:5c5e6001-1f77-4956-b078-399e36a4f77d> | 2.78125 | 127 | Knowledge Article | Software Dev. | 39.742475 |
I read in the newspaper this morning that a gentleman from Traverse City, Michigan found a dead shark in Lake Michigan. This did not surprise me. Rick Fasi discovered the two-foot long fish while boating and had it identified as a juvenile blacktip shark by an expert from the University of Florida. This species surprised me. I would have expected it to have been a bull shark. Let me give you some historical background on Lake Michigan and some surrounding freshwater rivers to explain why:
In September of 1937, the patience of Alton, Illinois anglers "Dudge" Collins and Herbert Copes was completely exhausted. More times than they cared to count, something—something big—had destroyed their Mississippi River fish traps while helping itself to a quick, easy meal. They guessed it was an opportunistic, gigantic catfish. They decided to end its marauding once and for all by setting a seine net to snare it.
When they returned they found that the trap had apparently worked, as the net’s buoys showed signs of a terrific struggle beneath the muddy water’s surface. What the men pulled up, though, left them shocked and scared. Ensnared in the net was a bull shark that was over five-feet long and 84 pounds. For those not familiar with bull sharks, here are a few facts:
- They can reach eleven feet in length.
- They are considered by divers to be the second most dangerous shark (after the great white). Unprovoked bull shark attacks on humans are not uncommon. Some studies have shown that bull sharks kill more humans per year than any other shark species.
- These unusual elasmobranches can not only survive in freshwater, but have been known worldwide to actually prefer it to saltwater. They are common inhabitants of—or visitors to—rivers that enter the ocean, such as the Ganges in India, the Zambezi in Africa, and our very own Mississippi and its tributaries.
Many authorities, presumably wanting to prevent panic among river dwellers and water-sport enthusiasts, insist that, due to the extensive lock-and-dam system built on the river shortly after the Alton catch, it would now be impossible for a shark to wend its way up the Mississippi, Illinois, or Ohio Rivers. That sounds comforting, but how can the authorities account for the following horror and oddity that occurred in 1955 and 1969 respectfully, well after the completion of the locks?
The day was beautiful, and consequently many were cooling off by boating or swimming in Lake Michigan. Among them was George Lawson, a boy from Chicago, who was swimming not too far from a boat off the shore. While splashing and playing, George was abruptly pulled underwater. Upon resurfacing, his screams for help brought John Adler to his rescue. Nevertheless, by the time he was brought into the boat, George’s right leg had been severed. The boat’s stunned passengers could do little but stare in dumbfounded awe at a large "tell-tale dorsal fin" that headed out to deeper water.
"I just couldn’t believe it, but I had to believe what I saw happening right before my eyes!" exclaimed a stunned Adler.
Doctors were certain that the boy’s injuries were inflicted by a shark, but were unable to explain from whence it came.
The second inscrutable encounter also played itself out on Lake Michigan. Anglers Gil Scharnek and Cal Lukasavitz literally stumbled upon a second shark specimen—much smaller, but a shark none-the-less.
"We saw a seagull sitting on what we thought was a piece of flotsam," recalled Scharnek. "When we got closer, the seagull flew away and we saw it was a fish. Cal said ‘Look, it’s a sturgeon,’ but when we got up to it we could see it was a shark."
The two brought the curiosity home with them, froze it and eventually had the identity of their find verified by a museum ecologist as a bull shark. Even though the lake’s temperature was a bone-chilling 42 degrees, the ecologist confirmed that even that was not too cold for a shark.Out-of-place animals have always fascinated me, but these sharks may have a purely biological origin...though blacktips are not known for their freshwater forays. The Michigan DNR, of course, proposed that "someone might have caught the shark of the Atlantic coast and kept it on ice while bringing it to norther Michigan." This begs the question: who keeps a two foot blacktip shark? | <urn:uuid:3e5c85a5-8cbd-49d9-82bf-855641488fd3> | 2.953125 | 965 | Personal Blog | Science & Tech. | 54.899167 |
This is a guest post from Melissa Lott, a dual-degree graduate student in Mechanical Engineering and Public Affairs at the University of Texas at Austin. Her work includes a unique pairing of engineering and public policy in the field of energy systems research. Melissa has worked for YarCom Inc. as an engineer and consultant in energy systems and systems design. She has previously worked for the Department of Energy and the White House Council on Environmental Quality for the Obama Administration. She is a graduate of the University of California at Davis, receiving a Bachelor’s of Science degree in Biological Systems Engineering. Melissa is also the author of the blog Global Energy Matters: Energy and Environment in Our Lives.
It has been almost two months since the Deepwater Horizon oil rig exploded and sank to the ocean floor in the Gulf of Mexico. Since then, a continuous stream of oil has contaminated our ocean and coastline, resulting in the worst environmental disaster in U.S. history. Efforts have been made to stop the flow of oil, but the solutions with the highest likelihood of success are still months from possible execution. This has left us with the troubling question of what we can do to minimize the negative environmental impacts of this oil. In particular, how do we clean up the massive quantities of oil already in the water? As it turns out, the answer to this might be found in Hollywood.
Kevin Costner, actor and apparent tech-aficionado, has a technology that is designed to quickly and effectively separate oil and water in order to minimize environmental damage from oil spills. Last Friday, the LA Times presented a lovely graphic (shown here) that illustrates and describes how this technology works in just six steps.
The final output of this machine consists of two streams. The first is 99% pure sea water, which can be directly piped back into the ocean. The second stream is 99% pure oil that can be stored onboard the vessels already at work in the Gulf. This could dramatically increase the effectiveness of these vessels in their fight against the constant stream of oil, allowing them to collect 99% pure oil instead of an oil-water mixture.
Costner’s technology isn’t new. In fact, he originally obtained the rights to develop and commercialize the prototype technology from the Department of Energy in 1992-93 via a technology transfer agreement. Since 1993, Costner has supported the development of this centrifugal separation technology by funding a business named Ocean Therapy Solutions (OTS) and its team of scientists. Today, the company has a series of five machines that can process 2 to 200 gallons-per-minute of contaminated water. Put another way, the largest of these models (the model V20) could likely remove 3,000 gallons of oil per day from the Gulf’s water.
What’s more, BP has already successfully tested these machines under “extreme” conditions and has signed on the dotted line to purchase 32 of them (presumably) for use in the Gulf. At least 31 of these are available for deployment today. Now, Costner and OTS are waiting for the oil giant to pay for the equipment before they deliver.
After nearly two months of feeling helpless, I am excited to hear about a technological solution that might help in the situation we have now – where the oil has already escaped and contaminated the surrounding environment. While this technology cannot stop the flow of oil or undo the damage already done to the gulf coast, it might limit future harm as we wait for the solution that will finally stop this oil leak. | <urn:uuid:76d42833-d929-4511-9a27-57503fb8280a> | 2.890625 | 719 | Personal Blog | Science & Tech. | 43.446935 |
Southeast Area Monitoring & Assessment Program: South Atlantic - SEAMAP
Shallow Water Trawl Survey
MRRI staff, funded by the Southeast Area Monitoring and Assessment Program - South Atlantic (SEAMAP-SA) of the National Marine Fisheries Service (NMFS) have been conducting a shallow water trawl survey in the coastal zone of the South Atlantic Bight since 1986.
The goal of this project is to monitor the status and trends of coastal species in the South Atlantic Bight, including fish, shrimp, crabs, horseshoe crabs, sea turtles, mantis shrimp, and squid, in order to amass a long-term data base for research and fisheries management use. Twenty-seven finfish and decapod species of key commercial or recreational interest, all sharks, all marine turtles, and horseshoe crabs are considered to be priority species. The project collects abundance and biomass data for all species, and lengths or widths for priority species. Priority species may have additional information such as individual weights, sex, sexual development, and/or tagging data recorded for them as well.
As the only coastal trawl survey that encompasses the entire Southeast region, this survey contributes to general knowledge of coastal species and aids numerous investigators and students by supplying data and specimens.
- This survey samples shallow coastal waters from Cape Hatteras, North Carolina to Cape Canaveral, Florida at depths from 15 to 30 feet. (Map of SEAMAP sampling strata)
- Samples are collected aboard the R/V Lady Lisa by towing paired 75 ft. mongoose-type Falcon Trawls for 20 minutes
- SEAMAP-SA Shallow Water Trawl Survey cruises are conducted each year in Spring (mid-April to the end of May), Summer (mid-July to mid-August), and Fall (the first of October to mid-November) | <urn:uuid:873239aa-5e7d-4427-bfc6-e5412ff61e27> | 3.046875 | 382 | Knowledge Article | Science & Tech. | 26.281429 |
.NET Framework General CLR: What is the Common Language Runtime?
Q: What is the Common Language Runtime?
A: The .NET Framework provides a runtime environment which runs the code and provides services that make the development process easier. This runtime environment in .NET Framework is known as Common Language Runtime (CLR). The CLR sits at the very heart of managed code. Common Language Runtime is the generalized multi-language, reflective execution engine on which code originally written in various languages runs. At a higher level, CLR is simply an engine that takes in Intermediate Language (IL) instructions, translates them into machine instructions, and executes them. Although the common language runtime provides many standard runtime services, managed code is never interpreted. A feature called just-in-time (JIT) compiling enables all managed code to run in the native machine language of the system on which it is executing. The CLR shares much in common with a traditional operating system.
Managed code is the term used for any code that is running on .NET Framework.
The CLR provides the infrastructure that enables managed code to execute as well provides variety of services during execution. When a method, for which IL has been generated, is called for the first time the CLR compiles the IL into native code that is specific to the processor the Environment it is running on (This process is known as Just in Time Compilation or JIT). If the same method is called next time, the existing JIT compiled code is reused. During execution managed code receives variety of services from the runtime environment.
When compiling to managed code, the compiler translates your source code into Microsoft intermediate language (MSIL), which is a CPU-independent set of instructions that can be efficiently converted to native code. Intermediate Language is a binary assembly language that is compiled at runtime down to whatever machine language is appropriate for the host CPU. This runtime compilation is called Just-In-Time Compiling or JIT-compiling.
Advantages of Managed Execution Environments
In unmanaged environments the compiler and linker directly compile the source code in to native instructions that are targeted at a specific processor. The disadvantage of this process is that each time you want to run your executable on a different platform you will have to re-compile the code using a compiler and linker that will compile the code that is targeted at the specific hardware. This means that each time you want your application to run on a different platform, you will have to ship the compiled instructions again and again. As this leads to compiling and maintaining multiple versions of the same application, the companies try to create a more generalized compiled version in order to target most of the environments. This process is known as the Lowest Common Denominator approach. This leads to a more generalized program which is not optimized properly and does not take advantages of the underlying hardware infrastructure (processor, cache, etc). Because the CLR supplies one or more Just in Time Compiler for each computer architecture it supports, the same set of MSIL can be JIT-compiled and run on any supported architecture. This
CLR provides the following benefits for developers:
Vastly simplified development.
Seamless integration of code written in various languages.
Evidence-based security with code identity.
Assembly-based deployment that eliminates DLL Hell.
Side-by-side versioning of reusable components.
Code reuse through implementation inheritance.
Automatic object lifetime management.
Code access security.
Cross Language Integration.
Self describing objects.
The CLR automatically handles object layout and manages references to objects, releasing them when they are no longer being used. This automatic memory management resolves the two most common application errors, memory leaks and invalid memory references. This process is known as Garbage Collection. The CLR also manages thread execution, code execution, code safety verification, compilation, and other system services.
The CLR is designed for the software of the future, and it also supports software of today and yesterday. Interoperability between managed and unmanaged code provided by CLR helps developers continue to use necessary COM components and DLLs. | <urn:uuid:4a1f2760-43c0-477d-81a7-b52aebcb8107> | 3.109375 | 835 | Q&A Forum | Software Dev. | 25.573919 |
This may not be as exciting a post as the one about the internal differences between these two groups, but it has lots of useful tips for any budding paleontologists who want to know if they've found a brachiopod or a bivalve.
All in all, this comes down to symmetry. If you hold a brachiopod in your hand so that you are only looking at one valve of the shell, and then you flip it over to look at the other valve of the shell, you'll notice they aren't the same. Do the same thing with a bivalve, and you'll notice they are. If you were to look at the two valves of a bivalve shell you would see that they are, in fact, mirror images of each other (with a few exceptions, most notably the oysters). This means that the plane of symmetry in a bivalve runs right along the hinge line.
For brachiopods, it's the opposite. The plane of symmetry in brachiopods runs perpendicular to the hinge line; if you cut a brachiopod in half perpendicular to the hinge line, you would see that both halves are mirror images of each other! Cool, huh? | <urn:uuid:01f549f2-58d0-4b92-9465-da4d9b2866a4> | 3.203125 | 251 | Personal Blog | Science & Tech. | 60.002488 |
Provided by: manpages-dev_3.27-1ubuntu2_all
makedev, major, minor - manage a device number
#define _BSD_SOURCE /* See feature_test_macros(7) */
dev_t makedev(int maj, int min);
int major(dev_t dev);
int minor(dev_t dev);
A device ID consists of two parts: a major ID, identifying the class of
the device, and a minor ID, identifying a specific instance of a device
in that class. A device ID is represented using the type dev_t.
Given major and minor device IDs, makedev() combines these to produce a
device ID, returned as the function result. This device ID can be
given to mknod(2), for example.
The major() and minor() functions perform the converse task: given a
device ID, they return, respectively, the major and minor components.
These macros can be useful to, for example, decompose the device IDs in
the structure returned by stat(2).
The makedev() major() and minor() functions are not specified in
POSIX.1, but are present on many other systems.
These interfaces are defined as macros. Since glibc 2.3.3, they have
been aliases for three GNU-specific functions: gnu_dev_makedev(3),
gnu_dev_major(3), and gnu_dev_minor(3). The latter names are exported,
but the traditional names are more portable.
This page is part of release 3.27 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/. | <urn:uuid:595b224c-18b7-4f89-9914-a27084a1cdc3> | 2.796875 | 389 | Documentation | Software Dev. | 50.442166 |
Click on the "Create Excited State Band" button to the right of the energy level diagram. An excited state band appears. Then click the "Create Impurity State Band" button below, and an impurity state band appears below the excited state band. The are the bands in the material that is used to coat the insides of the fluorescent lamps.
Drag the "Input Energy" slider at the bottom left of the screen to increase the input energy of the First Source to the infrared detector. Observe the marker on the vertical scale of the energy level diagram rise to indicate the increase in the impute energy. When the input energy is greater than the energy of the excited state band. Click the "Turn on Lamp" button. The Mercury gas in the diagram above begins to glow with a color corresponding to the input spectrum energy. On the energy level diagram observe a transition from the ground state to the excited state and then another from the excited to the impurity state, and then from the impurity state to the ground state. The energy corresponding to this last transition appears on the Output spectrum below the energy level diagram and the lamp on the left of the screen begins to glow with that color. The material of the coating in the cross sectional view below the lamp also begins to glow.
Click the "Edit Properties" button, and observe then click and drag the energy bands on the energy level diagram. After adjusting the bands to a new value, you may need to alter the input energy on the slider so that the input energy is greater than the excited state band energy. Then click the "Turn on Lamp" button to repeat the transitions.Direct comments to: Chandima Cumaranatunge (programming aspects); Sanjay Rebello (physics content). | <urn:uuid:c4071c9e-442c-4b9f-a3fe-757478680de7> | 3.390625 | 358 | Tutorial | Science & Tech. | 47.890782 |
I've recently come across a derivation, which I've not seen before, of mass increase in special relativity. It seems to make sense, but I get tripped-up on an intermediate step, and I can't seem to ...
In General Relativity Theory, mass can warp spacetime. However, in my view interaction only occurs between pieces of matter. Spacetime is not matter; how can it be affected by matter?
I know that mass can bend fabric of space-time, which causes gravity by making an object curve around a planet or star but is there anything else that can bend it? Other energy sources, forces ...
I understand that an event, in a four dimensional space-time, produces a light cone. As time increases the cones gets larger on either side of the event (past and future). For example the if the sun ...
I understand only a little of general relativity, but that's why I'm here! :) Consider the hypothetical situation of some extra-terrestrial intelligence pushing all the mass in the universe, every ... | <urn:uuid:bbcaa498-e5d2-4087-a4f6-129fb6009377> | 2.734375 | 215 | Q&A Forum | Science & Tech. | 53.601052 |
What Are Hydrothermal Vents?
Hydrothermal vents are places along the seafloor where hydrothermal fluid emerges and mixes with bottom seawater.
How Is Hydrothermal Fluid Produced?
When seawater percolates through fissures, or fractures, in the ocean crust, it is heated to temperatures that can reach well beyond 400°C or 752°F (water can exist as a supercritical fluid at these sites) as it reaches the magma chambers underneath. The hot water then reacts with surrounding rocks, changing its chemical composition in the process. As the water is heated, it then becomes less dense than the cold water and quickly rises, escaping through vents. The acidic hydrothermal fluid, rich in sulfides and other metals that leach from rocks, mixes with the slightly basic bottom seawater. As a result of the two mixing, minerals form these chimneys and plumes or clouds of fine black particles that can be seen in the photos above. These are also known as black smokers.
Why Are Hydrothermal Vents Significant?
One of the reasons why hydrothermal vents are significant is because they are actually homes to remarkable biological communities, such as tube worms seen in the second picture in the first row. They are sites of many unique ecosystems that thrive on chemical energy (from the oxidation of hydrogen sulfide present in the hydrothermal fluid) as opposed to light from the sun.
Also, some researchers say that hydrothermal vents may have been a site for the origin of life. You can read more about that at Science Daily.
Images Credit: 2012 MBARI | <urn:uuid:14ab8c6f-ef16-4e75-b646-da961edbbe3e> | 4.125 | 335 | Knowledge Article | Science & Tech. | 43.366324 |
May 19, 2013
Your search for Paleontology in Evolution returned 88 articles
A collection of articles and multimedia, lesson plans and other resources for teaching about Darwin and evolution.September 21, 2011, Wednesday
Lice are expert evolvers, and a new family tree of lice stretches so far back that the host of the first louse would have been a dinosaur.April 12, 2011, Tuesday
Books about evolution by Nick Lane, Carol Kaesuk Yoon, Iain McCalman and Colin Tudge.August 30, 2009, Sunday
Seventy paleontologists visited the Creation Museum in northern Kentucky for a jarring alternate view of geological history.June 30, 2009, Tuesday
Fossil remains of a 47-million-year-old animal have been determined to be an extremely early primate close to the emergence of the evolutionary branch leading to humans.May 16, 2009, Saturday
The extinct people nicknamed hobbits remain mystifying anomalies in human evolution, out of place in time and geography, their ancestry unknown.April 28, 2009, Tuesday
Scientists describe a well-preserved and practically complete fish fossil that is 418 million years old.March 31, 2009, Tuesday
To the Editor: Re ''The Cons of Creationism'' (editorial, June 7):June 11, 2008, Wednesday
Peter Parnell’s play is a tightly focused study of Darwin, his family and his intellectual circles.December 06, 2007, Thursday
They may never persuade other scientists the earth is young, but creationist geologists are having an impact on other Christians.November 25, 2007, Sunday
SEARCH 88 ARTICLES ABOUT EVOLUTION:
Evolutionary biologists and historians of science comment on Charles Darwin’s “On the Origin of Species.”
Sean B. Carroll discusses the science of evolution and the growing field of evo-devo.
A tour of the new Hall of Human Origins at the American Museum of Natural History.
From the Archive
Now, browse the expanded New York Times Archive back to 1851. Articles are available as PDFs. | <urn:uuid:60cfd0e7-6664-4662-b9f0-2ee59f87077e> | 2.90625 | 435 | Content Listing | Science & Tech. | 42.282615 |
... What needs to be standardized, then, is not the language per-se, but the rules by which a language is selected. The IF statements. If you read through the standards documents on the IETF's website, you are not looking at a single, all-encompassing rule. You are looking at possibly a few thousand rules, with enough logic behind them to determine which rule applies. ..."
Every so often an insightfull, perhaps even usefull post appears on slashdot. I like the pragmatic approach to the discussion in the article linked to above - the author seems to have an appreciation of the root problem that can get "mis-solved" in language standardisation. | <urn:uuid:5d5ef0b2-691e-4e96-931c-6e759a938ca3> | 2.75 | 140 | Comment Section | Software Dev. | 57.556288 |
Video:What Are Causes of Global Warmingwith Amrita Ngen
Scientists have determined some of the causes of global warming to be related to human activities. Learn more about the causes of global warming and what you can do to lessen your impact on the environment.See Transcript
Transcript:What Are Causes of Global WarmingScientists have determined that a number of human activities are contributing to global warming by adding excessive amounts of greenhouse gases to the atmosphere. Greenhouse gases such as carbon dioxide accumulate in the atmosphere and trap heat that normally would exit into outer space.
Greenhouse Gases Are Causes of Global WarmingWhile many greenhouse gases occur naturally and are needed to create the greenhouse effect that keeps the Earth warm enough to support life, human use of fossil fuels is the main source of excess greenhouse gases.
By driving cars, using electricity from coal-fired power plants, or heating our homes with oil or natural gas, we release carbon dioxide and other heat-trapping gases into the atmosphere. Deforestation is another significant source of greenhouse gases, because fewer trees means less carbon dioxide conversion to oxygen.
During the 150 years of the industrial age, the atmospheric concentration of carbon dioxide has increased by 31 percent. Over the same period, the level of atmospheric methane has risen by 151 percent, mostly from agricultural activities such as raising cattle and growing rice.
What Are Consequences of Global WarmingAs the concentration of greenhouse gases grows, more heat is trapped in the atmosphere and less escapes back into space. This increase in trapped heat changes the climate and alters weather patterns, which may hasten species extinction, influence the length of seasons, cause coastal flooding, and lead to more frequent and severe storms.
Thanks for watching. To learn more, visit About.com. | <urn:uuid:cdaae494-9679-4cb0-8b00-3f71eeeda8a3> | 3.46875 | 358 | Truncated | Science & Tech. | 29.255828 |
Science Fair Project Encyclopedia
In computational complexity theory, NP ("Non-deterministic Polynomial time") is the set of decision problems solvable in polynomial time on a non-deterministic Turing machine. Or, equivalently, the set of decision problems that can be reformulated as a binary function A(x, y) over strings such that
- for a certain constant number c it holds that a string x is an element of the original decision problem iff there is a string y with length smaller than |x|c such that A(x, y),
- the function A is decidable by a Turing machine in polynomial time.
An y value for a certain x such that A(x, y) holds is usually referred to as a certificate for x since it shows the membership of x to the original decision problem.
The importance of this class of decision problems is that it contains many interesting searching and optimization problems where we want to know if there exists a certain solution for a certain problem. Examples are the traveling salesman problem where we want to know if there is a route of some length that goes through all the nodes in a certain network and the satisfiability problem where we want to know if a certain formula in propositional logic with propositional variables is satisfiable or not. In both cases there is a certificate (a path that of that length, a truth assignment that makes the formula true) that is limited in size and for which we can decide in polynomial time whether it solves the problem.
Because of its importance there have been many efforts to come up with algorithms that decide the problems in NP in polynomial time. However, it seems that for some problems in NP we cannot come up with an essentially better algorithm than the one that simply tries all possible certificates until we find the right one. Whether this is really true or not is still one of the big open questions in computer science (see Complexity classes P and NP for an in-depth discussion). An important notion in this context is the set of NP-Complete decision problems, which is a subset of NP and might be informally described as the "hardest" problems in NP. These are problems that if there is a polynomial-time algorithm for even one of them, then there is a polynomial-time algorithm for all the problems in NP. Because of this, once a problem has been proven to be NP-complete this is widely regarded as a sign that a polynomial algorithm for this problem probably does not exist.
A commonly used equivalent characterization of the problems in NP is this: if, given a solution, that solution can be checked for validity in polynomial time, the problem is in NP. The nondeterministic Turing machine essentially has a "guessing unit" that allows it to guess all the bits needed to construct the right answer, if one exists. If the correctness of the answer can then be verified by a polynomial-time algorithm, then the problem is solvable in nondeterministic polynomial time. There are many common problems that can be solved in this way; if one can calculate the "quality" of a solution in polynomial time, then a decision version of the problem, such as "is there a solution with quality better than k", can be solved by a nondeterministic polynomial-time Turing machine.
There is also a simple logical characterization of NP: it contains precisely those languages expressible in second order logic restricted to exclude universal quantification over relations, functions, and subsets.
The decision version of the traveling salesperson problem is in NP. Given an input matrix of distances between N cities, the problem is to determine if there is a route visiting all cities with total distance less than k. A nondeterministic Turing machine can find such a route as follows:
- At each city it visits it "guesses" the next city to visit, until it has visited every vertex. If it gets stuck, it stops immediately.
- At the end it verifies that the route it has taken has cost less than k in O(n) time.
One can think of each guess as "forking" a new copy of the Turing machine to follow each of the possible paths forward, and if at least one machine finds a route of distance less than k, that machine accepts the input.
What makes this a natural decision version of the problem is that, if we could solve this problem quickly, we could use binary search to solve the original computation problem (finding the route and its exact length) quickly as well.
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details | <urn:uuid:bd83d5fe-f45c-4a34-bff9-0cf599e8ab1d> | 3.34375 | 974 | Knowledge Article | Science & Tech. | 35.406479 |
cripting languages exist because some programming tasks are both simple and important, and carrying them out with a language that doesn't tax the mind as much as a system programming language sometimes will is beneficial. (See Sidebar: Scripting vs. Programming
for a full explanation of the differences between scripting languages and programming languages.) Although Java is most decidedly a programming language (it is typed, highly structured, and compiled), don't you sometimes wish you could do scripting in Java, or something close to Java?
Thanks to the Reflection API, you can. Using the Reflection API, you can run methods dynamically. Java's support of reflection enables you to create an interpreter that executes commands interactively. This article describes a system you can use to build an interpreter into your application. It demonstrates how to build a reflection-based system that allows simple scripting of Java programs without having to install a special-purpose scripting language. It also provides a downloadable sample program. This solution can allow you to create simple control scripts for your Java programs.
The Scripting "Language"
Before I get to the implementation, let's take a look at the "language." I put the word language in quotes because this language is so crude it hardly merits the term. It has no control structures, no types, no variables, no keywords, and no expressions. It simply allows you to call a Java method. Nevertheless, it constitutes a language, which makes our implementation an interpreter.
Here's an example of a command in this language:
TinyChatServer startServer 5000
This command starts up a chat server listening on port 5000. The chat server is implemented by a class called
TinyChatServer, which has a method called
static public String startServer( int port );
In general, each command has the format shown in Figure 1.
Each command consists of a class name, a method name, and one or more arguments. Here's another example of a command:
Calculator add 10.0 20.0
Our interpreter interprets this command by calling the
add method of the
Calculator class, and passing it two arguments: | <urn:uuid:6f4c3ffa-0f0b-47d0-bccb-60e5001d66fc> | 3.4375 | 437 | Documentation | Software Dev. | 43.068099 |
Flexible thin-film solar panels to make harnessing solar energy more affordable
Major drawbacks in using silicone panels to harness solar energy are their cost and their bulky nature. However, very soon these may be problems of the past. Recently developed technology to produce thin-film solar panels can make them flexible so that they could be rolled up into sheets and laid out on a roof without being very apparent. In recent years, the cost of using solar panels has reduced as their efficiency has increased. According to Abound Solar, a company based in Colorado, thin-film solar panels can be used to generate energy at $1 per watt, which is very low when compared the effective cost of $4 per watt while using silicone solar panels.
Though thin-film solar panels aren’t as effective as silicone solar panels, which can harness about 20.3% of the total energy incident on them, efforts are going on to increase their efficiency so that using solar energy can be more convenient and affordable. | <urn:uuid:900dca17-d2a1-4390-9f9f-a3a69a9197c6> | 2.78125 | 202 | Truncated | Science & Tech. | 35.044798 |
Study of the use of gaseous xenon as a detector medium for hard x-ray astronomy
Hard x-ray detectors are used to study black holes, neutron stars and active galactic nuclei. In xenon gas the energy of an incident x-ray gets converted to scintillation light, the strength of which is proportional to the energy of the x-ray absorbed. In the laboratory we have been studying this process. More details on this project.
Development of rapid photometric techniques for the study of stellar signal variations
We acquire hundreds or thousands of images of a rich star field in a given night. We then perform a statistical analysis of the signal (= “apparent brightness”) each star in the field over the course of the night. While this work should prove useful for the study of everything from meteors to near-earth asteroids to variable stars, we are primarily interested in searching for foreground objects that pass between us and a distant star, leading to a sudden and brief decrease or increase in the flux measured from the background star. More details on this project. | <urn:uuid:d765feb7-6f48-40b2-b307-3ba768b166be> | 2.765625 | 220 | Content Listing | Science & Tech. | 45.095435 |
WHEN sperm whale mothers dive deep for squid their young cannot follow - so who looks after the kids?
Shane Gero of Dalhousie University in Halifax, Nova Scotia, Canada, and his colleagues tracked sperm whale populations in the Caribbean and Sargasso seas to see what happened when mothers dived for food. The Sargasso mothers formed a babysitting circle, taking it in turns to watch over and nurse the calves, and to go hunting. The smaller Caribbean population had fewer mothers, so calves were left with a close female relative instead (Behavioral Ecology, DOI: 10.1093/beheco/arp068).
It makes evolutionary sense for females to protect their young relatives, and for a mother to babysit in return for its own calf's protection. There may be a less obvious reason, too: a group that watches each other's infants will grow larger, making it safer for all. "Among sperm whales, having extra eyes in ...
To continue reading this article, subscribe to receive access to all of newscientist.com, including 20 years of archive content. | <urn:uuid:7ed1ca00-7259-4b84-aaa4-b74a0d14fee3> | 3.890625 | 227 | Truncated | Science & Tech. | 50.138992 |
In this tutorial, We will discuss about <ul> tag in html5. The <ul> tag is used for defining a unordered list. The unordered list represented items as listing without number. The changing of the list item order will not affect the meaning of list . In The unordered list the list is created by <li> tag, and <ul> tag must have opening and closing tag.
The syntax for the <ul> tag is as:
|<ul>List Of Items Here </ul>|
<title>Example of unorderlist Tag</title>
Difference Between html5 and html4.01.
There is no attribute of this tag in html5. "type" and "compact" attribute is not supported by html5.
Ask your questions, our development team will try to give answers to your questions. | <urn:uuid:1b4b7074-be78-41dc-a188-739d3cd97460> | 3.4375 | 178 | Tutorial | Software Dev. | 68.938885 |
Buckyballs Jiggle Like Jello
This artist's animation illustrates vibrating buckyballs -- spherical molecules of carbon discovered in space for the first time by NASA's Spitzer Space Telescope. These molecules jiggle, shimmy and shake in a variety of ways -- 174 to be exact. Four of these vibrational modes cause the molecules to either absorb or generate infrared light. Thanks to these jiggles, Spitzer's infrared vision was able to detect the long-sought signatures of buckyballs in space.
Browse Videos in Science Animations
This artist's animation illustrates how silicate crystals like those found in comets can be created by an outburst fr... | <urn:uuid:4756209f-aa91-49bf-8706-81c8cc22687a> | 3.046875 | 138 | Truncated | Science & Tech. | 34.199029 |
There are over 350,000 different species of beetles in the world which is close to 40% of all described insect species. This means that a staggering 1 in 4 of all animal species is a beetle.
Beetles are mostly land dwellers, but there are some species of beetle that live in freshwater (these freshwater beetles are described in the pond life section). Interestingly though, there are no beetles that live in the sea.
Beetles have biting mouth parts, 3 pairs of legs and 2 pairs of wings. The rear wings are soft and generally used for flying and the front wings are generally modified to provide a tough protective covering for the flight wings when the creature is at rest or not flying.
In England there are close to 4,000 beetle species and in our A-Z we have described 12 individual beetle species (including the Glow-worm, Nut Weevil, Devil’s Coach Horse and the Seven-spot Ladybird) to provide an indication of the variety of beetles found in this country. | <urn:uuid:126b6e3d-1549-4a66-8839-c981e3be7e07> | 3.609375 | 207 | Knowledge Article | Science & Tech. | 53.732586 |
Wildlife includes those wild animals that are not domesticated and are not in captivity. At one time, the term referred only to those birds and mammals considered to be game animals. These animals were hunted for sport, such as the white-tailed deer, gray squirrel, cottontail rabbit, wild turkey, ruffed grouse, bobwhite quail, and wood duck. Game animals also included those furbearers that were trapped, including mink, muskrat, beaver, red fox, gray fox, and raccoon. Game animals were commonly categorized as upland game animals (deer, bear, rabbits, and squirrels), upland game birds (quail, turkey, and grouse), wetland game birds (ducks, geese, and woodcock), and wetland furbearers (beaver, mink, and muskrat).
In the past, wildlife traditionally did not include fish, which were considered to be a separate group. Fish historically were classified by biologists as either game fish or commercial fish, and little research and management effort were devoted to the nearly 100 other species of fish found in West Virginia waters. Game fish were those pursued for sport, such as the bass, trout, pike, and muskie, while commercial fish were those harvested for sale, such as buffalo, carp, channel catfish, and flathead catfish.
As biologists recognized the value of animals other than the game animals and game and commercial fish, the definition of wildlife was broadened to include the hundreds of species that were not hunted, trapped, or fished. During the 1970s, a distinction was made between game and nongame wildlife. The term ‘‘nongame wildlife’’ was used to describe those birds, mammals, and fish that were not hunted, trapped, or fished, including such animals as songbirds, hawks, owls, bats, mice, shrews, minnows, darters, and creek chubs. It was recognized that these animals had economic, scientific, and recreational value, as well as intrinsic worth. Efforts were initiated to preserve and manage nongame birds, mammals, and fish, which throughout West Virginia were much more numerous than were the game animals and game fish. There currently are approximately 50 species of game animals compared to 320 species of nongame animals, and approximately 25 species of game fish compared to more than 150 species of nongame fish.
By the 1980s, amphibians such as frogs, toads, and salamanders, plus reptiles such as lizards, snakes, and turtles, were also included with nongame wildlife. Thus, all vertebrates were considered to be wildlife, although fish were typically placed in a separate category of wildlife. The definition of wildlife broadened even more during the 1990s, and some of the larger and more appealing invertebrate species—butterflies, moths, mussels, and snails—were included.
An even broader definition of the term wildlife now in use encompasses not only all vertebrates, but also most invertebrate species, with small worms, insects, and spiders being included. The most liberal definition includes plants along with all kinds of animals. However, this definition has not yet received wide acceptance within the scientific community and is generally not accepted by the general public.
West Virginia’s wildlife may be classified according to habitat. Wetland wildlife, forest wildlife, grassland wildlife, and wilderness wildlife are groups of animals that typically live in those specific habitats. Wetland wildlife include such animals as the beaver, muskrat, mink, wood duck, Canada goose, great-blue heron, snapping turtle, bullfrog, and spring peeper. Forest wildlife include the black bear, gray squirrel, flying squirrel, great horned owl, pileated woodpecker, and redback salamander. Grassland wildlife include the red fox, meadow vole, cottontail rabbit, meadowlark, song sparrow, kestrel, garter snake, smooth green snake, and box turtle. Wilderness wildlife in West Virginia are quite rare and include the mountain lion (now absent), golden eagle, and timber rattlesnake.
Most wildlife living in West Virginia are year-round residents, but a few—primarily birds seasonal visitors. All fish, amphibians, reptiles, and most mammals (other than a few bats) are year-round residents, while the majority of the more than 300 bird species known to occur in West Virginia are present only during certain months. Approximately 70 species of birds spend all 12 months in the Mountain State, while many others are seasonal residents or simply pass through while migrating. Examples of permanent residents are the mallard, Canada goose, red-tailed hawk, ruffed grouse, wild turkey, great-horned owl, pileated woodpecker, blue jay, crow, raven, chickadee, and cardinal. Among the nearly 100 seasonal residents that spend the summers nesting in West Virginia are the hummingbird, flycatchers, warblers, and thrushes. Fewer than 10 birds (cormorant, rough-legged hawk, and evening grosbeak) spend only the winters in West Virginia and typically nest farther north. Many wetland birds (including many waterfowl and shorebirds) are migratory visitors and may be observed only during the fall and spring months as they migrate between northern nesting grounds and southern wintering grounds. Most invertebrates are year-round residents although a few butterflies (notably the monarch) regularly migrate through West Virginia.
There have been significant changes in the species and numbers of resident wildlife in West Virginia. Some animals that were common prior to settlement—buffalo, elk, gray wolf, and passenger pigeon—had disappeared from the state by 1900. Other common wildlife present prior to the state’s settlement had become so rare by 1900 that biologists predicted they would probably disappear during the 1900s. Some of these at-risk species were the beaver, river otter, mountain lion, wood duck, black bear, and fisher. As a result of reintroduction and management by the Wildlife Resources Section of the Division of Natural Resources, however, these species are all now more numerous than they were in 1900. The notable exception is the mountain lion, believed to have been extinct in the state since the 1930s.
Certain species of wildlife that faced extinction in West Virginia during the early 1900s have recovered to levels where they are now causing serious damage. The beaver, white-tailed deer, raccoon, and Canada goose are so abundant that their numbers need to be controlled. Others—black bear and wild turkey currently causing problems in some areas and could become serious pests in the future. The past century has demonstrated that wildlife are much more adaptable than biologists previously imagined, and if protected from hunting and harassment, most animals can live near humans. Bald eagles, osprey, and river otter were rare in West Virginia during the 20th century, but through adaptation most likely will become relatively common in West Virginia in the future. Perhaps the mountain lion will join them.
Some wildlife that historically were never known to occur in West Virginia are now found widely scattered throughout the state. For example, coyotes expanded their geographic range from the Southwest and are now present in every county in West Virginia. Another species, the elk, was once common in West Virginia, then lost, and now seems likely to return. The native herd in Pennsylvania is growing, and elk have been sighted in southwestern West Virginia, presumably from the herd introduced into Kentucky from the West.
Canada geese and bald eagles were rare visitors to West Virginia during the early 1900s, but were not known to nest here. Canada geese now nest in most counties, and bald eagles nest along the Potomac River and the Ohio River. Selected wildlife species were intentionally introduced into North America and have spread throughout West Virginia and most of the United States. Examples of these exotic species are the English sparrow, European starling, pigeon, and carp. Other wildlife species, such as the house mouse, Norway rat, black rat, and zebra mussel, were introduced accidentally into North America, and have become serious pests throughout West Virginia and other states. In contrast, a few exotic species have been intentionally released into West Virginia because of their sporting values as game animals or game fish and are now an integral and valued part of West Virginia’s wildlife, including the brown trout, rainbow trout, ring-necked pheasant, and wild boar.
Another category of wildlife present in West Virginia is the group termed feral. These are animals that have returned to an untamed state following domestication; they are free-living and do not depend on humans for food or shelter. House cats are probably the most common feral animal in West Virginia, followed by feral dogs and goats.
In contrast to those species that have increased in numbers, many other wildlife species that were common during the 1800s have experienced serious declines throughout much of West Virginia. The numbers of spadefoot toads, upland chorus frogs, timber rattlesnakes, bobwhite quail, barn owls, whippoorwills, pink mucket pearly mussel, fanshell mussel, and clubshell mussel are now considerably lower than they were 100 years ago. The reasons for these declines are not fully understood, although loss of suitable habitat is the most likely factor.
The next 100 years will bring many noticeable changes to the wildlife of West Virginia. Some species will disappear and some will become rare, while others will become more abundant, and a few will certainly become pests. Regardless of the changes, the diversity of fascinating wildlife will be an integral part of West Virginia’s natural history.
This Article was written by Edwin D. Michael | <urn:uuid:9f898c68-ea1a-4e64-964d-dc841ebd5338> | 3.75 | 2,027 | Knowledge Article | Science & Tech. | 30.881321 |
The result of division is to separate a group of objects into several equal smaller
groups. The starting group is called the dividend. The number of groups that are
separated out is called the divisor. The number of objects in each smaller group is
called the quotient.
The results of division can be obtained by repeated subtraction. If we are separating
24 objects into 6 equal groups of four, we would take (or subtract) four objects at
a time from the large group and place them in 6 equal groups. In mathematical terms
this would be: 24-4-4-4-4-4-4. | <urn:uuid:3d06d102-0551-41ed-b327-b4011d98f2af> | 4.6875 | 132 | Knowledge Article | Science & Tech. | 69.517476 |
For the first time scientists have demonstrated the impact of climate change on ocean warming and sea surface temperatures affecting global fisheries stocks. Previous studies were limited to individual fisheries. The changes have been occurring clearly since the 1970s, the scientists say. The implications of this research raises the need for timely changes in fisheries management practices and adaptation plans for communities dependant on fishing, particularly climate vulnerable developing countries in the tropics.
"Given global fisheries contribute hugely to the world's economy and food security, this is a significant finding," said co-author Dr Reg Watson from the University of Tasmania's specialist Institute for Marine and Antarctic Studies."We are no longer talking about future hypotheticals - we are talking about impacts on a global scale that we can already demonstrate."
Previous research by Dr Watson published last year demonstrated that marine fishes are now smaller in size. "Last year we showed that one of the consequences of climate change and excessive fishing is that globally marine fishes are smaller," said Dr Watson.
The paper - Signature of ocean warming in global fisheries catch - was published in Nature on 15 May 2013. The study was lead by Assistant Professor William Cheung, University of British Columbia, with collaboration from Professor Daniel Pauly and Dr Reg Watson.
I wrote about a related issue on the Velocity of climate change imperiling ocean diversity, particularly with regard to Australia, in January 2012. | <urn:uuid:0a0d7411-ebc6-4da0-ad6e-9ad855f297b8> | 3.4375 | 276 | Knowledge Article | Science & Tech. | 21.361486 |
Attention Grist and Wikipedia readers:
Please see this comment on the linking of this post from those websites (update Jan 2 2008).
We had a cool talk on Friday about carbon sequestration in mine tailings.
First, the background:
For the past couple billion years, the primary planetary thermostat is generally thought to have been the carbonate-silicate geochemical cycle. Weathering processes remove CO2 from the atmosphere with the following reaction (using diopside as an example mineral): CaMgSi2O6 + 2CO2 -> CaMg(CO3)2 + 2 SiO2. subduction and continental metamorphism reverse the reaction: CaMg(CO3)2 + 2 SiO2 -> CaMgSi2O6 + 2CO2. This works for all calcium and magnesium silicates, not just diopside. The metamorphic part is assumed to proceed at a constant rate. The weathering part is dependent on temperature and p CO2. So when CO2 and temperature are high, the reaction proceeds faster. As CO2 is removed from the atmosphere, the planet cools, and the reaction slows down. Without human interference, this cycle is expected to correct the current anthropogenic CO2 increase in about 0.1 Ma.
Now, the observation:
Scientists studying mine tailings in abandoned asbestos mines in Canada found that the tailings (which are primarily serpentine: Mg3Si2O5(OH)4) were covered in white crusts- various hydrated magnesium carbonate species. Detailed study ensued.
The details (which I’m skipping since it’s after midnight and I’m only up because the baby is) are in themselves pretty awesome, as they show how the scientists sourced the carbon and investigated the relative importance of biotic and abiotic processes in reacting the tailings. Their conclusions are that in the 20 years since the mines closed, the tailings had sequestered as much CO2 as the mining operations originally produced, making the mines carbon-neutral. Even better, the potential sequestration capacity of the unreacted serpentine in the tailings was substantially higher. Now they are trying to figure out how to accelerate the process, in the hopes that all mantle or mafic cumulate-based mines can sink carbon as a byproduct of production. In true lab style, they’ve evidently got labs full of tailings-packed tupperware reacting at all sorts of temperature, pH, and fluid activities.
We don’t currently mine enough nickel, chromite, or asbestos for this to be a stand-alone solution for all emissions, but in theory it could sequester up to about 0.1 Gt of carbon per year- substantially more than is used to operate the mines.
I love this kind of science, for several reasons. Firstly, it is one of those things that is bleeding obvious once observed, but still quite unexpected. If mine tailings weren’t reactive, we wouldn’t have mine pollution issues. So how could hundreds of millions of tons of powdered mafics fail to react with the atmosphere?
Secondly, it makes absolutists’ brains explode. Just when the left wing fruitcake faction of environmentalists thought that bird-killing windmills and nuclear power plants were the worst thing to come out of global warming, along comes this new discovery: What we really need to do to save the planet is to dig up more asbestos, nickel, and chromium.
The UBC mineral carbonation group
American Mineralogist abstract (full article available for fee) | <urn:uuid:cb6227d5-084f-4235-947b-e0594bb1b3ff> | 2.9375 | 751 | Personal Blog | Science & Tech. | 39.660812 |
A University of Delaware PhD student has a machine that cold jump-start the hydrogen economy. ->
In Die Another Day, James Bond drove a car that used tiny screens and cameras to make itself invisible. This week, Mercedes did the same thing, but for real, driving its new B-Class F-Cell prototype around Germany with only the wheels showing. But the German automaker didn't pull the stunt to imita...
Highlighting the Mercedes-Benz brand at the Frankfurt Motor Show is the F125! F-Cell plugin hybrid concept that celebrates the brand's first 125 years of motoring prowess while at the same time paves the way for its future. The F125! showcases Mercedes' vision of emission-free driving with hydrogen...
Pulling hydrogen out of water can be done with bacteria, wastewater and seawater.
An Italian team of researchers claims to have discovered cold fusion. It will either change the world or be another fruitless and premature "breakthrough."
A cockroach's body chemistry could power tiny implants.
Natural sugars in your body power this implantable gizmo.
Upgraded microbial fuel cells turn waste into energy without the harmful environmental effects.
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Chemical Equilibrium Practice Problems
1. For the rusting of iron initially at equilibrium, predict the shift in the reaction with each perturbation.
3 Fe(s) + 4 H2O (g) <---> Fe3O4 (s) + 4 H2 (g) + heat
a) Increase the amount of water
b) Decrease the volume by half
c) Remove Fe3O4 as it is formed
d) Add hydrogen to the mixture
e) Increase the temperature
2. Hydrogen chloride reacts with oxygen to yield chlorine and water. An equilibrium can be established with this reaction. An experiment was performed in a closed vessel starting with a mixture of 0.50 M HCl and 0.050 M O2. The amount of chlorine was monitored until no change was observed, at 0.048 M chlorine.
a) Which way did the system shift to achieve equilibrium?
b) What is Kc for this reaction, and what are the equilibrium concentrations of all relevant components?
c) What is Kp for this reaction if the final temperature is 25°C? | <urn:uuid:c0d9c763-8659-4e53-b2b9-5813c37716db> | 3.84375 | 231 | Tutorial | Science & Tech. | 69.203746 |
Hunting Bears with a Microscope
Olathe East High School
E-mail: click here
In this study, students will use lichens and tardigrades (water bears) to investigate their use as bioindicators of key air pollutants. When lichens are exposed to some kinds of air pollutants, especially to sulfur dioxide (SO2), the lichens are injured and die. The lichen coverage in a specified area should be a good indicator of the level of air quality. Tardigrades are macroinvertebrates living in and on lichens. The diversity of the tardigrade species on the lichens will be used to develop another level for bioindication of air quality.
IntroductionLichens are small, nondescript, often overlooked organisms. Once we notice them growing on the surfaces of trees, rocks, up the sides of buildings, and in mossy carpets in our forests, we cannot fail to admire the way in which they color our world. Lichens are actually two organisms existing in a symbiotic relationship know as mutalism. Lichens are typically composed of a green algae and a fungus. Lichens can also be composed blue-green algae, yellow-green algae, or cynobacteria living in association with different kinds of fungi. Lichens are classified based on the fungal component. The fungi are either Ascomycetes (sac fungi), Basidiomycetes (bracket fungi), or Deuteromycetes ( imperfect fungi). Lichens appear in a wide variety of habitats because they can tolerate, and in fact thrive, under difficult environmental conditions. The alga manufactures and provides itself and the fungus with carbohydrates and some vitamins. Some blue-green algae can even fix nitrogen from the air. In turn, the fungus provides the alga with certain physical protection, it obtains water vapor from the air, providing moisture for the algae. In addition the fungus converts the carbohydrate produced by the algae into a sugar alcohol for food storage. In addition to this relationship between the two organisms, lichens have special adaptations permitting them to withstand moisture and temperature extremes. When moisture is available, it is taken up by the fungus leading to a mechanical change which allows more light to get through, triggering algal photosynthesis. When the atmosphere is dry the lichen is dormant and does not grow.
Tardigrades live in lichens and are unusual organisms that most people would rarely see. In fact, lodged within the lichens is a surprising diversity of microscopic invertebrates and protozoan that awaits reviving. These animals can survive periodic drying that occurs naturally in lichens by entering a special metabolic state called cryptobiosis. During cryptobiosis microinvertebrates weather dry conditions by suspending all but the most vital life functions. These microscopic animals range from 0.1 to 1.0 millimeters and live wherever trees and lichens grow.
Samples of lichens with as many as five species of tardigrades as well as rotifers, nematodes mites, small insect larvae and various protozoa have been found. Tardigrades are distributed worldwide and thrive in diverse habitats including marine, terrestrial and freshwater environments. Terrestrial tardigrades become active only when surrounded and rehydrated by water. Reanimated tardigrades cling to substrate and search slowly for food. These "water bears" as they are commonly called, use four pairs of stumpy, clawed legs to lumber through the water. When surrounding water evaporates, tardigrades can eliminate as much as 90% of their body water. This loss of body water is called anhydrobiosis and leads to a cryptobiotic state in which tardigrades assume a desiccated form called a tun. Tardigrades can survive for months or even years as tuns, remaining inactive until reanimated with water. When moistened, a 120 year-old museum specimen of dried moss yielded tardigrades showing signs of life.
The hardy lichens, and the community living on them, may provide a useful bioindicator for air pollution since they derive their water and essential nutrients mainly from the atmosphere rather then from the soil. It also helps that they are evergreen and able to react to air pollutants year round. In addition, compared with most physical/chemical monitors, they are inexpensive. They can also be used to measure toxic elemental pollutants and radioactive metals because they bind these substances in their fungal threads where they concentrate over time.
Sulfur Dioxide and LichensLichens are injured by sulfur dioxide (SO2 ). Rose (1975) has calculated that more than one-third of England and Wales has lost nearly all its epiphytic lichens, the most delicate shrubby lichens, largely due to the sulfur-dioxide emissions of coal-burning power plants. In Northern Siberia, an area of the Soviet Union which is very polluted, the number of lichen species has fallen from 50 to about 3, and the lichen production in general stands at about 1 or 2% of normal levels, threatening the reindeer diet; in Alaska there are similar concerns about lichen reduction and the caribou diet.
Losses in other parts of the world reflect the increasingly poor quality of the earth's air and the need for early warning bioindicators such as lichens. This pollutant has natural sources, such as volcanic eruptions and sea spray. By far the largest source for it, however, is the combustion of fossil fuels, automobile emissions, and some industrial processes. The pollutant is carried in the atmosphere until rained out or deposited as dry particles or as gas. Sulfur dioxide combines with moisture in the atmosphere to form sulfurous acid (H2SO3) or sulfuric acid (H2SO4). When this happens with rainwater, the result is acid rain. All these forms of sulfur are harmful to lichens and plants. Lichens have also shown sensitivity to some other pollutants, such as heavy metals and ozone, but for the most part lichen damage can be attributed to SO2 .
The effect of pollution upon lichens can depend on the pH of the substrate, the surface on which the lichen grows. In general, an alkaline substrate such as basic bark or limestone counteracts the acidity of SO2 pollution. As acid rain falls on a substrate, one kind of lichen growth form will often be replaced by another more tolerant form. In areas of high pollution lichens may be found only on sites such as wounds on trees and on sandstone walls, which have high (basic) pH. Scientists have found that, with considerable SO2 pollution in an area;
- The first loss of the same pH-sensitive lichens occurs on birches and conifers
(acid bark and low buffering capacity);
- The next loss on oaks and sycamore (intermediate acidity and buffering capacity);
- The last on trees like elm (alkaline bark and high buffering capacity).
Lichen communities are either weakened or killed by pollution with a consequent loss of species diversity. Lacking the protective cuticle of higher plants, lichens accumulate sulfur dioxide in their thalli bodies in sufficient concentrations to quickly injure or kill them. They also accumulate metals, some of which are toxic, and as they store these toxic metals safely in their hyphal cell walls, they can be professionally evaluated for toxin levels.
The lichen's symptoms of sulfur dioxide death are distinctive. The lichen turns from its usual gray or green hues to the more unusual brown, yellow, pink or white as its chlorophyll is lost. It starts to peel away from its substrate. The sizes of lichen thalli often decrease, especially in fruticose lichens. Fewer spores are produced. The centers of circular lichen colonies usually die first, leaving rings and crescent patterns on rocks or trees.
Sampling Procedure for Lichen CoverageThe following procedures are intended to standardize collection so results can be more easily compared with those of other sites.
- Use trees that are within one kilometer of your school site.
- Record the latitude and longitude of your school site on the data collection table.
- Try to choose trees with alkaline bark, preferably ash, but if not ash, then elm or sycamore. If need be, use trees with acid bark, preferably oak, but if not oak, then beech or birch.
- If you do not know the pH of your trees, scrape some bark into water and measure with a pH probe, if you have access to one, or with a pH strip test.
- Select 10 mature trees within the one kilometer radius around your school. These ten trees should be of the same species, if possible. Mark the tree for later identification. At each selected mature tree of your selected species, tie a string around the trunk at a height of one meter.
For each tree, fill in the information for your site on the following lines.
pH of the Bark _________________________________________________
To estimate the degree of cover we will use a belt transect with accurate determination of cover. Record your tree's identification number on the chart below. Make sure your string around the tree is one meter above the ground at all points. Determine North, South, East, and West using a compass and mark these points on the tree. Copy the 100-dot grid at the end of this lab onto acetate, making a transparent copy. Place the transparent grid so that it's lower edge touches the string on the tree and is in the center of each quadrant, i.e., north, south, east, west. To observe and record percentage cover by each type of lichen, simply count what is showing through each of the 100 small circles and record on the chart below. Each column should add up to 100%. Repeat this procedure for all 10 trees.
Tree _______ North South East West Crustose Foliose Fructicose Moss Bare Bark Other
Tardigarde SamplingStudents collect samples of lichens from the bark of area trees. The samples are taken to the classroom and submerged in water to reanimate the tardigrades living in the lichens. The exercise provides students the opportunity to make basic ecological calculations and introduces the concept of diversity.
The following procedure will be helpful in collecting lichens for use in tardigrade sampling. Lichens are sensitive slow growing organisms. Collection should be limited to necessary samples.
Sampling Procedure for Tardigardes
- The lichens should be collected from the same 10 trees used for the lichen coverage study, but not from the transect area.
- Use an area of bark that is 100% covered by lichens. Use a large cork borer 1 3/32 inch, or as large as you can find, to collect the lichens. Some samples will be easily collected while others will require that the bark of the tree be collected also. The student should record the tree identification number.
- When students return to the classroom they should invert the lichen samples in Petri dishes (lichen down), half full with filtered spring water, deionized, or with distilled water. Each lichen sample should have it's own Petri dish. The water rehydrates desiccated tardigrades and other invertebrates that the students will observe. The soaking will reanimate these animals in 24 hours but 48 or 72 hours will yield better results.
- Have the students remove the lichens and search the Petri dishes for tardigrades (water bears). The search should be systematic and uniform, following a simple pattern throughout the dish. Ask the students to construct a data table to record numbers of tardigrades in each sample.
- Help them develop a method of categorizing the tardigrades into different species or types. These categories may be based on the tardigrade's size, color, smooth or ornamented cuticle, alive or dead, presence of eggs, or any meaningful separation of observable characteristics the students wish to use. If the students wish to use a more advanced method of classification a good reference is : Morgan, C.I., & P.E. King (1976) British Tardigrades: Keys and notes for the identification of the species. New York: Academic Press. Counts should be made three times and recorded on the chart below.
- Calculate the average of each type of tardigrade and the total of each count.
Tree_____ Species Count 1 Count 2 Count 3 Average Tardigrade A Tardigrade B Tardigrade C Tardigrade D Tardigrade E Total
To calculate the density of tardigrades students should determine the lichen surface area for the sample they are observing. If a cork borer was used to collect the lichens, the area of the lichen sample is:
Lichen Area = (3.14)(radius of the sample) 2
Density of the tardigrades is calculated by dividing the number of tardigrades observed by the area of the lichen sample. Density is calculated for each type of tardigrade by dividing the number of each type of tardigrade observed by the total surface area of the lichen.
Tardigrade Density Type A = Number of tardigrades Type A/Lichen Area Tardigrade Density Type B = Number of tardigrades Type B/Lichen Area
Calculate the mean density by summing the densities of all the types of tardigrades and dividing by the number of types found.
Mean Density = Density of type A + Density of type B
Calculating diversity using the Simpson Diversity IndexCalculate the proportion of the total number of tardigrades of each type (Pi).
Proportion type A (Pa) = number of Type A/Total number of tardigrades Proportion type B(Pb) = number of Type B/Total number of tardigrades
To calculate the Simpson Diversity Index = 1-Pi2
For example, if you looked at 50 tardigrades classified as type A and 20 tardigrades of type B you would calculate:
Diversity Index = 1- ((50/70)2 + (20/70)2)
Diversity Index = .41
This index ranges from zero to one and is literally a measure of the probability that two tardigrades taken at random from the sample are different species. A number close to zero means low diversity and it is likely you will get the same species of tardigrade and a number close to one means high diversity.
Interpretation of resultsOnce data have been obtained, a follow-up discussion in the classroom can correlate the results with environmental influences such as light, wind direction, exposure to pollution, and other factors.
With this data in hand, you may want to;
Laying out a grid of the data permits a more systematic sampling of an area. Use the data from many sites to produce a map of lichen coverage over a large area and to observe patterns.
- Collaborate with other schools in your district to create a local lichen coverage map.
- Collaborate with other ecological regions to create a larger scale lichen coverage map.
Find someplace where SO2 is being monitored and correlate these measurement with your lichen data.
ReferencesThis research activity has been developed by relying on the Lichen Investigations of the TERC Global Lab project and on an original article, Diversity in a Hidden Community: Tardigrades in Lichens by Marcia Shofner and Darrell Vodopich, appearing in The American Biology Teacher, October 1993. | <urn:uuid:a3b41af2-773d-4432-87de-4450ed7ed45a> | 3.765625 | 3,275 | Academic Writing | Science & Tech. | 38.404015 |
Science Fair Project Encyclopedia
The Soviet reusable spacecraft program Buran ("Бура́н" meaning "snowstorm" or "blizzard" in Russian) began in 1976 at TsAGI as a response to the United States Space Shuttle program. Soviet politicians were convinced that the Space Shuttle could be used for military purposes, hence posing a potential threat to the balance of power during the Cold War. The project was the largest and the most expensive in the history of Soviet space exploration.
Because Buran's debut followed Space Shuttle Columbia's and there were visual similarities between the two shuttle systems, during the Cold War many speculated that espionage played a role in the development of the Soviet shuttle. However, it is now known that while externally it was an aerodynamic copy of the Space Shuttle, internally it was all engineered and developed domestically.
Key differences with the NASA Space Shuttle
- Buran was designed to be capable of both manned and unmanned flight, it had automated landing capability; the manned version has never been operational
- The orbiter had no main rocket engines, freeing space and weight for additional payload; the largest cylindrical structure is the Energiya carrier-rocket, not just a fuel tank.
- There were four boosters instead of two, and they used liquid propellant (kerosene/oxygen)
- The Energiya carrier, including the main engines, was designed to be reusable but funding cuts meant that a reusable version of Energiya was never completed. The U.S. Space Shuttle has reuseable main engines in the orbiter and reusable Solid Rocket Boosters.
- Buran could lift 30 tonnes to orbit, against the Space Shuttle's 25 tonnes.
- The high lift-drag ratio of the space aeroplane Buran is 6.5 against 5.5 for Space Shuttle
- Buran returned 20 tonnes of payload against 15 tonnes for Space Shuttle orbiter from an orbit to an aerodrome
- The cutting lay-out pattern of thermoprotection tiles of Buran is optimal and longitudinal slits of tile belts are orthogonal to the flow line. Sharp angles of tiles are absent.
The development of the Buran began in the early 1970s as a response to the U.S. Space Shuttle program. While the Soviet engineers favored a smaller, lighter lifting body vehicle, the military leadership pushed for a direct, full scale copy of the delta wing Space Shuttle, in an effort to maintain the strategic parity between the superpowers.
The construction of the shuttles began in 1980 and by 1984 the first full-scale Buran was rolled out. The first suborbital test flight of a scale-model, however, took place as early as July 1983. As the project lasted, five additional scale-model flights were performed. With the first full-scale Buran, 24 test flights were performed after which the shuttle was "worn out".
The first and only orbital launch of the (unmanned) shuttle Buran 1.01 was at 3:00 UTC on 15 November 1988. It was lifted into orbit by the specially designed Energiya booster rocket. The life support system was not installed and no software was installed on the CRT displays.
The shuttle orbited the Earth twice before returning, performing an impressive automated landing on the shuttle runway at Baikonur Cosmodrome. The U.S shuttles landings are also mostly automated (there has only been one manually flown re-entry so far), but deployment of the landing gear requires a human to physically press the button. The manual step was added at the insistence of the astronauts, who claim that early deployment of the landing gear due to a computer error would be fatal. A premature deployment at many points in re-entry would destroy the shuttle in a fashion similar to the Space Shuttle Columbia.
Part of the launch was televised, but the actual lift-off was not shown. This led to some speculation that the mission may have been fabricated, and that the subsequent landing may not have been from orbit but from a shuttle-carrying aircraft. (Note that in the United States, this procedure was used to test the flight characteristics of the Space Shuttle on approach and landing using the Approach and Landing Test vehicle Space Shuttle Enterprise, so that by the time mission STS-1 drew to a close, the handling characteristics of Space Shuttle Columbia would be known.) However the launch video has now been released to the public confirming that the shuttle did lift-off, the poor weather conditions described by the Russian media at the time can be easily seen.
After the first flight the project was suspended due to lack of funds and the political situation in the Soviet Union. The two subsequent orbiters, which were due in 1990 (codename Ptichka - little bird) and 1992 respectively were never completed. The project was officially shut down in 1993.
The program was to have carried out research, national-pride, and technological objectives similar to those of the U.S. shuttle program, including resupply of the Mir space station, which was launched in 1986 and remained in service until 2001. When Mir was finally visited by a spaceplane, the visitor was an American shuttle — not Buran.
The completed shuttles 1.01 and 1.02 ('Ptichka'), and the remains of the project are now property of Kazakhstan. In 2002, the hangar housing the sole space-flown Buran 1.01 orbiter and a mockup of the Energiya booster rocket collapsed due to incomplete maintenance, destroying the vehicle. Eight workers were also killed in the collapse of the building's roof.
Burans 2.01 and 2.02 (This second series had a modified flight-deck design) never left the Tushino factory and remain there in poor condition. Parts from these vehicles are being sold on the Internet.
The partially built Buran 2.03 was dismantled when the programme was closed, and no longer exists.
As well as the five 'production' Burans, there were eight test vehicles. These were used for static testing or atmospheric trials, and some were merely mock-ups for testing of electrical fittings, crew procedures, etc.
Serial numbers and current status
- OK-M (later OK-ML-1) - Static Test - Now at Baikonur Cosmodrome
- OK-GLI - Aero Test
- OK-KS - Static Electrical/Integration Test - Now at the Energia factory in Korolev
- OK-MT - Engineering Mock-up - Now at Baikonur Cosmodrome
- OK-??? - Static Test - Status unknown
- OK-TVI - Static Heat/Vacuum Testbed - Status unknown
- OK-??? - Static Test - Status unknown
- OK-TVA - Static Test - Now in Gorky Park, Moscow
The OK-GLI test vehicle was fitted with four jet engines mounted at the rear (the fuel tank for the engines occupied a quarter of the cargo bay). This Buran could take off under its own power for flight tests, which is a contrast to the American 'Enterprise' test vehicle, which was entirely unpowered and relied on an air launch.
After the programme was cancelled, OK-GLI was stored at Zhukovsky Air Base , near Moscow, and eventually bought by an Australian company called 'Buran Space Corporation'. It was transported by ship to Sydney, Australia via Gothenberg, Sweden (account of the operation) - arriving on February 9 2000, and appeared as a static tourist attraction under a large temporary structure in Darling Harbour for a few years.
Visitors could walk around and inside the vehicle (a walkway was built along the cargo bay), and plans were in place for a tour of varous cities in Australia and Asia. The owners, however, went into bankruptcy, and the vehicle was moved into the open air, where it suffered some deterioration and vandalism. It is now in Bahrain.
The grounding of the US space shuttles has caused many to wonder aloud whether the Russian Energia launcher or Buran shuttle could be brought back into service. The reality of the situation is that all the equipment for both (including the vehicles themselves) have fallen into disrepair or been repurposed since falling into disuse with the collapse of the Soviet Union.
Buran in Science Fiction
Shuttle Buran, alongside with another Soviet space orbiter project, Spiral, is used in Sergey Lukyanenko's The Stars Are Cold Toys novel. Equipped with the fictional jumper engine, Buran is one of the primary means of interstellar trade with aliens.
- Energiya - The booster rocket, the second part of the "Buran-Energia" space system.
- Antonov An-225 - The world's largest aircraft (by MTOW), built to carry the Buran
- Mir space station
- Baikonur Cosmodrome
- Encyclopedia Astronautica: Buran
- buran.ru -- The official website by the NPO "Molniya", makers of the Buran.
- Images and information, very nice design
- Russian Aviation page
- Buran The Russian Shuttle - Gizmohighway Technology Guide
- Mir-Shuttle Docking Module - Astronautix.com
- German aviation museum acquires Buran test article for display (in German)
- Buran's first flight, lift-off video
- Web Site on Buran in Sydney
- landing video
The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details | <urn:uuid:dfef03bd-b2ca-4e09-bd35-6245eeee48c9> | 3.9375 | 2,001 | Knowledge Article | Science & Tech. | 45.410754 |
let x = mass of gold. let y = mass of quartz
x + y = 100 the sum of the masses is 100g
(x / 19.3) + (y / 2.65) = (100 / 6.4) This says the sum of the volumes equals the total volume.
Use your favorite 2 equation, 2 unknown method to solve for x and y. You could say x = 100 -y and substitute this into the second equation.
You get: x = 67.9 g of gold and y = 32.1 g of quartz | <urn:uuid:c9042f66-f820-490f-b065-a60d8c8b7d6b> | 2.9375 | 117 | Q&A Forum | Science & Tech. | 114.01893 |
The fruiting bodies of fungi are known as mushrooms, and are used for culinary purposes or intoxication depending on variety, although many contain deadly toxins. The scientific study of fungi is known as mycology.
In the biblical creation worldview, fungi were created by God during the Creation Week approximately 6,000 years ago. The Bible suggests that the mycorrhizal, endophytic, and land-dwelling, saprophytic fungi were likely created on Day 3 along with plants, while other fungi (that is, animal-associated Candida spp. and the aquatic Chytridiomycetes) were created on Days 5 and 6. | <urn:uuid:1a82bd7f-4aca-4b67-b901-a2474159da4b> | 3.515625 | 136 | Knowledge Article | Science & Tech. | 32.953 |
Grasslands of Virachey National Park, Cambodia.
Not much is know about the biodiversity of Southeast Asia. In Cambodia, years of conflict have prevented scientists from gathering data regularly and limited conservation efforts. Fortunately, in October 2007 our scientists were able to conduct a biological survey of Virachey National Park, one of Cambodia’s most unique protected areas. While the final report is still pending, preliminary results provide a glimpse into this poorly studied and fascinating area.
Virachey National Park is located in the northeast corner of Cambodia, near the borders with Laos and Vietnam. It is the largest national park in Cambodia, and one of the least accessible. Mountain ranges with no footpaths or villages have both protected the area and prevented biological assessments.
The park contains many types of habitats, including bamboo, pine forest, semi-evergreen rain forest, and dry dipterocarp forest. The most widespread habitat is its tropical evergreen rain forest, most of which is in pristine condition.
The team consisted of local and international scientists, led by Conservation International.
Mr. Neang Thy (reptiles and amphibians, Government Counterpart, MOE)
Dr. Jodi Rowley (amphibians, CI)
Dr. Bryan Stuart (reptiles and amphibians, Museum of Vertebrate Zoology, USA)
Mr. Stephane De Greef (ants)
Mr. Heng Naven (freshwater fishes)
Mr. Som Sitha (tortoises and freshwater turtles)
Mr. Hay Dalino (bears)
Ms. Sett Sophak (bears)
Dr. Piotr Naskrecki (insects, CI)
Staff of Virachey National Park
The team flew via helicopter into Virachey National Park from the provincial capital, Banlung, and surveyed the area for 15 days.
The objective of the survey was to gain a better understanding of the biological importance of Virachey National Park and highlight its importance for biological conservation. The survey will lead to the production of a detailed report for the Ministry of the Environment, which will help the ministry raise funds to protect and conserve the unique biodiversity of Virachey National Park.
Full results of this report are still pending, however, the preliminary report indicates that the surveyed area of the camp contained an extremely high diversity and abundance of species, including at least:
Reports included direct observations of several large mammal species (e.g., Sambar deer (Cervus unicolor
), wild dog, also known as dhole (Cuon alpinus
), and various species of wild cattle) and recent tracks and signs of other mammals (e.g., bears, clouded leopards). Many of these mammals are considered globally threatened.
IN DEPTH: Read more about the species discovered and identified from the preliminary report. | <urn:uuid:4ee42b6f-6cb6-4ede-afc7-1ba1e3a70edf> | 3.40625 | 594 | Knowledge Article | Science & Tech. | 36.969187 |
- Special Sections
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LOS ANGELES (AP) — Scientists are abuzz about a coal-colored rock from Mars that landed in the Sahara desert: A yearlong analysis revealed it’s quite different from other Martian meteorites.
Not only is it older than most, it also contains more water. The baseball-size meteorite, estimated to be 2 billion years old, is strikingly similar to the volcanic rocks examined by the NASA rovers Spirit and Opportunity on the Martian surface.
“Here we have a piece of Mars that I can hold in my hands. That’s really exciting,” said Carl Agee, director of the Institute of Meteoritics and curator at the University of New Mexico who led the study published online Thursday in the journal Science.
Most space rocks that fall to Earth as meteorites come from the asteroid belt, but a number can be traced to the moon and Mars.
Scientists believe an asteroid or some other large object struck Mars, dislodging rocks and sending them into space. Occasionally, some plummet through Earth’s atmosphere.
If you currently subscribe or have subscribed in the past to the Los Alamos Monitor, then simply find your account number on your mailing label and enter it below.
Click the question mark below to see where your account ID appears on your mailing label.
If you are new to the award winning Los Alamos Monitor and wish to get a subscription or simply gain access to our online content then please enter your ZIP code below and continue to setup your account. | <urn:uuid:c81eb5c6-a64d-4dd5-b118-0b175c469035> | 3.375 | 318 | Truncated | Science & Tech. | 41.772557 |
Look up monthly U.S., Statewide, Divisional, and Regional Temperature, Precipitation, Degree Days, and Palmer (Drought) rankings for 1-12, 18, 24, 36, 48, 60-month, and Year-to-Date time periods. Data and statistics are as of January 1895.
Please note, Degree Days are not available for Agricultural Belts
Arizona Temperature Rankings, November 1947
More information on Climatological Rankings
(out of 119 years)
|2nd Coldest||2000||Coldest to Date|
|117th Warmest||1995, 2007||Warmest since: 1946| | <urn:uuid:d37e71cf-c573-42e4-a5aa-726dae862137> | 2.703125 | 133 | Structured Data | Science & Tech. | 48.859886 |
The first truly Earth-like alien planet is likely to be spotted next year, an epic discovery that would cause humanity to reassess its place in the universe.
While astronomers have found a number of exoplanets over the last few years that share one or two key traits with our own world — such as size or inferred surface temperature — they have yet to bag a bona fide "alien Earth." But that should change in 2013, scientists say.
"I'm very positive that the first Earth twin will be discovered next year," said Abel Mendez, who runs the Planetary Habitability Laboratory at the University of Puerto Rico at Arecibo.
Astronomers discovered the first exoplanet orbiting a sunlike star in 1995. Since they, they've spotted more than 800 worlds beyond our own solar system, and many more candidates await confirmation by follow-up observations.
NASA's prolific Kepler Space Telescope, for example, has flagged more than 2,300 potential planets since its March 2009 launch. Only 100 or so have been confirmed to date, but mission scientists estimate that at least 80 percent will end up being the real deal.
Kepler telescope needs to witness three of these"transits" to detect a planet, so its early discoveries were tilted toward close-orbiting worlds (which transit more frequently). But over time, the telescope has been spotting more and more distantly orbiting planets — including some in the habitable zone.
An instrument called HARPS (short for High Accuracy Radial velocity Planet Searcher) is also a top contender, having already spotted a number of potentially habitable worlds. HARPS, which sits on the European Southern Observatory's 3.6-meter telescope in Chile, allows researchers to detect the tiny gravitational wobbles that orbiting planets induce in their parent stars.
Whenever the first Earth twin is confirmed, the discovery will likely have a profound effect on humanity.
"We humans will look up into the night sky, much as we gaze across a large ocean," Marcy told SPACE.com via email. "We will know that the cosmic ocean contains islands and continents by the billions, able to support both primitive life and entire civilizations." | <urn:uuid:98eb823b-1001-4dd0-b1b8-96b1c171f681> | 3.421875 | 438 | Comment Section | Science & Tech. | 38.717908 |
DAMS on the River Rhône in Switzerland are threatening to turn the crystal waters of Lake Geneva into a deoxygenated, weed-covered dead zone, say researchers at the University of Geneva.
Over the past forty years, engineers have built nine large hydroelectric dams on the tributaries of the Upper Rhône, the main source of water for the lakethe shoreline of which is known as the Swiss Riviera.
One result has been to disrupt the seasonal flow of the river. The dams capture the peak summer flows from melting snow and glaciers, and release the stored water through turbines during the winter to provide electricity. Crucially, the dams have eliminated the summer floods that were once a feature of the river and which generated currents that brought badly needed supplies of dissolved oxygen into the otherwise stagnant depths.
Now biologists Jean-Luc Loizeau and Janusz Dominik have calculated the impact of the dams ...
To continue reading this article, subscribe to receive access to all of newscientist.com, including 20 years of archive content. | <urn:uuid:65deebe8-5139-4b87-928a-fd4d3284352d> | 3.25 | 217 | Truncated | Science & Tech. | 40.343279 |
Report an inappropriate comment
Warmer Seas May Rob Rainforests And Corals Of Clouds
Fri Feb 19 22:31:13 GMT 2010 by W G Treharne
The acidification of the oceans shows that we cannot tolerate a higher level than 390 parts per million of CO2.The tipping point may be lower than this, thus we need research to establish the exact tipping point. A series of tanks of varying parts per million of CO2 will help to show.
Harvesting small pieces of coral may help to keep the sea level down. | <urn:uuid:38821050-a8df-432d-9ed1-f430c2e891da> | 2.78125 | 113 | Comment Section | Science & Tech. | 70.32397 |
Electrophoresis is a process for separating charged molecules based on their movement through a medium under the influence of an applied electric field. This module will introduce some of the early adaptations of electrophoresis in human identification laboratories. The next module deals with the technology used today.
In 1807, Russian scientist F. F. Reuss observed the migration of particles in an electrical field establishing the foundation for the work of the Swedish chemist Arne Wilhelm Tiselius. In 1930, Tiselius introduced a method for separating proteins in suspension using electric currents, which was termed electrophoresis. He was awarded the 1948 Nobel Prize in chemistry for this work.01, 02, 03 Today, electrophoresis has many applications for separation of the components of mixtures and is the method of choice for amplified DNA product separations.
Upon successful completion of this unit of instruction, the student shall be able to:
- Explain the process of electrophoresis.
- Identify the components for successful separation of amplified DNA products.
- Compare and contrast the methods of agarose gel and polyacrylamide electrophoresis.
- Describe the methods used to detect amplified DNA products separated using different types of stab gel electrophoresis apparatus.
< Previous Page :: Next Page > | <urn:uuid:cdabe21e-fa8a-42aa-b6e6-62845a98df58> | 3.796875 | 267 | Tutorial | Science & Tech. | 22.051994 |
Junk DNA—or, as scientists call it nowadays, noncoding DNA—remains a mystery: No one knows how much of it is essential for life. As one scientist mused, “Is the genome a trash novel, from which you can remove a hundred pages and it doesn’t matter, or is it more like a Hemingway, where if you remove a page, the story line is lost?” However enigmatic, though, noncoding DNA has proved mighty useful for scientists in one way—it’s great for tracking evolution, through so-called DNA clocks.
DNA clocks take advantage of the fact that DNA mutates at a constant rate: Every so many years, a new mutation should pop up along a stretch of DNA. So in examining the natural history of two related species—which once had the same DNA sequence—a scientist can count the number of different mutations that have accumulated along a stretch, and estimate from that how many years have passed since the species started drifting apart. Except it’s not quite that simple. Mutations can arise anywhere in the genome, in gene DNA and noncoding DNA alike. But mutations to genes have bigger consequences: They can disable proteins and kill a creature. As a result, mutations within genes often get weeded out and don’t get passed on to future generations. Noncoding DNA faces fewer constraints—it can mutate more freely without causing problems when it’s passed along. Counting mutations in noncoding DNA therefore provides more accurate estimates in many cases because the timer there isn’t getting reset. | <urn:uuid:db44dfe0-f179-4b85-a554-f1e7330e5c83> | 3.8125 | 332 | Truncated | Science & Tech. | 40.325629 |
3JH,H calculationThe magnitude of three-bond 1H-1H coupling constants is determined mainly by the torsion angle between the protons but substituents, especially electronegative ones, do also affect the coupling. They influence the coupling in two ways; they cause a change in overall magnitude of the Karplus equation, and they cause a shift of the maxima and minima of the curve. Several attempts have been made to account for these effects.
The program here calculates 3JH,H values according to C.A.G. Haasnoot, F.A.A.M. DeLeeuw and C. Altona; Tetrahedron 36 (1980) 2783-2792. The actual equation is rather complex and requires the electronegativities of all substituents to be entered.
Since the equation requires the relative orientation of the substituents a molecular model will be of help.
Turn the model so that the proton on the near side is pointing up then use the schemes below to determine the numbering of the substituents (e.g. S1, S2 etc.) and select the appropriate elements from the menus.
The paper (above) contains set of different equations (A-E) for use under different circumstances. The program will automatically select an equation (C, D, or E) depending on the number of attached hydrogens. (Equations A and B are 'general' and give slightly higher deviations - however the difference between the equations is not great)
It is also possible to calculate the torsion angles that correspond to a particular 3JH,H-value. There can be one to four angles depending on the size of the coupling constant. | <urn:uuid:269e6c31-7845-4b19-a6fd-dcd1ccb930e0> | 2.71875 | 362 | Tutorial | Science & Tech. | 51.41611 |
Birds are the only animal form found in any climatic condition, anywhere in the world. They have no geographic barriers.
Colombo, 50 years ago used to have large populations of crows, feral pigeons and house sparrows. The house sparrow and the pigeon population declined with the closure of the granaries in the city. But not the crows.
The crow population multiplied in such numbers that one had to walk under an umbrella in the parks and the tree lined avenues in the evenings. Day time was no better, the writer as a school boy could remember the “crow scarer” at the Fort Railway Station who carried a device that would give out the sound of cannon-fire every now and then to scare away the crows on the steel trusses of the station roof. All this was to protect the people from their droppings.
The Colombo Crows (Kolamba Kaka) were the problem birds in the 60’s and 70’s where even projects to poison them were discussed in the boardrooms of the city fathers. They have since survived the discussions and time, by bringing down their own numbers to tolerable levels. Today, we do not see them as a nuisance anymore.
Animals including crows are found to be opportunistic. They would exploit a situation for their benefit. Crows being omnivorous thrived on the freely available garbage and waste during these periods. If one goes down memory lane there were times when the city garbage was a sorry sight throughout the day. The crow population increased immensely scavenging on the garbage. The improved disposal of city waste has had an impact on the food source resulting in reduced breeding. This type of control in population with the availability of food resources is instinctive in the animal kingdom.
The crow is said to pair for life just like us, and one can see them grooming each other lovingly. The male is always in close proximity to the shabby nest while the female sits on the eggs. They are very aggressive during this period and attack any intruders to the nest. During non-breeding periods, they prefer to roost in the colony where they start assembling at fading light. The night temperature in cities is a few degrees warmer than the surrounding areas, and the mass gathering of birds keeps the roost warm. This increased temperature is favourable to start activities fairly early in the morning.
Most roosting birds require warmth from the morning sun for effective blood circulation, to become active. Birds are thought to have poor eyesight at night, and sleeping in the city gives the advantage of being safe from predators. The illuminated city below the roost is advantageous to fly to in an emergency.
On the other hand these communal roosts act as social gatherings where birds challenge each other, find potential mates, and communicate in one way or another, of available feeding grounds etc. Many of these nightly inhabitants in a communal roost are young non-breeders.
This explains why the destruction of birds in these roosts has not been successful in bringing down the populations. If you eradicate every bird in the roost, you would still leave the breeding population virtually untouched, and these breeding birds are quite successful in replacing the lost population in a very short period of time.
It would be interesting to analyze the control of the crow with relation to our own changes that have come about in the recent past.
The outdoor fish and meat stalls are now indoor supermarkets where meat and fish are pre-dressed or processed for sale; thereby the waste matter is minimal. The bio-degradable garbage is either turned into compost in small home units or delivered to the collecting trucks in an organized form instead of being dumped on the wayside.
The Crow is the biological indicator in the control of garbage in the city; the cleaner the city, the fewer the number of crows.
The efficiency of these biological indicators is evident at Horton Plains. There were no crows in Horton Plains in the 60’s and 70’s. But ever since it was declared a National Park, became a holiday destination and every nook and cranny filled with garbage, things have changed. There is now a crow up there eagerly waiting for you.
(The writer is a Life Member of the Field Ornithology Group of Sri Lanka of the Department of Zoology in the University of Colombo) | <urn:uuid:f123a520-ef76-458a-b29c-fa8940abac02> | 3.21875 | 899 | Nonfiction Writing | Science & Tech. | 46.521602 |
The Marsh Fritillary Euphydryas aurinia is one of the fastest declining species in England, recorded as losing 66% of its colonies in England between 1990 and 2000..
The Marsh Fritillary breeds in open grassy habitats, especially damp grassland dominated by tussock-forming grasses; calcareous grassland (usually on west or south-facing slopes) and heath and mire vegetation. Devil’s-bit Scabious Succisa pratensis is the larval foodplant.
Thewet grasslands or Rhôs pastures of Dartmoor are recognised as one of the Marsh Fritillary’s UK strongholds but even here they have been affected by the loss of unimproved grassland, mainly due to agricultural improvement and changes in land management.
On Dartmoor, lack of grazing is a common problem. Under-grazed, neglected or abandoned habitat patches quickly become unsuitable for the butterfly, as European Gorse Ulex europaeus, Western Gorse Ulex galli and willow Salix spp. scrub dominate and the grass sward becomes rank and overgrown, shading out foodplants. As habitat loses condition through lack of management, connectivity within the landscape is reduced, leaving the remaining patches isolated and their Marsh Fritillary colonies vulnerable.
To reverse the declines of the Marsh Fritillary across Dartmoor by introducing butterfly-friendly management on unoccupied as well as occupied patches to increase the area of potential breeding habitat and improve connectivity between these patches.
- Scrub control fencing/boundary works undertaken, to enable grazing by hardy cattle or ponies to be re-introduce.
- Felling of small areas of woodland and cutting of hedges, to create clear flight paths and improve connectivity between habitat patch.
- Planting of Devil’s-bit Scabious, to improve the quality of breeding habitat.
- Support given to Natural England staff - assisting in agri-environment applications and ensuring appropriate management prescriptions are included in the agreement terms.
- Training events organised for conservation professionals, landowners and contractors.
- Volunteers recruited and organised to undertake practical management and species monitoring.
- Guided walks and other public events held to increase understanding and appreciation of butterflies.
For more detailed information about this project and others across the UK please read the full report: Landscape-scale Conservation For Butterflies And Moths: Lessons From The UK.
- Working with landowners and Natural England staff, the project helped to secure Higher Level Stewardship agreements at eight farm holdings on one valley system (on which suitable habitat patches had been identified), supporting appropriate management over a ten year agreement period.
- Between 2005 and 2010 the area of confirmed occupied habitat in the Fernworthy-Long Lane network rose from 33 ha to 86 ha. The number of habitat patches occupied by the butterfly tripled and number of larval webs in this valley increased by 1,082%.
- Conservation measures taken to help the Marsh Fritillary has helped to maintain and restore habitat on a landscape-scale for other declining Lepidoptera, such as the Narrow-bordered Bee Hawk-moth Hemaris tityus and Small Pearl-bordered Fritillary Boloria selene, as well as a wide range of other flora and fauna found in wet pastures.
This project demonstrates why agri-environment schemes, such as Environmental Stewardship, are a key mechanism to deliver targeted management across whole landscapes to benefit threatened butterflies and moths. Over £100k in funding was secured through agri-environment scheme agreements and other sources for one valley system, which supported capital expenditure on fencing and scrub control and provided landowners with area-based payments to graze their habitat with low numbers of hardy animals suited to this type of rough grassland at the appropriate time of year. | <urn:uuid:bd504e33-3387-457f-8918-66913dd79947> | 3.515625 | 795 | Knowledge Article | Science & Tech. | 20.746052 |
indirection definition programming
Manipulating data via its address. Indirection is a powerful and general programming technique. It can be used for example to process data stored in a sequence of consecutive memory locations by maintaining a pointer
to the current item and incrementing it to point to the next item.
Indirection is supported at the machine language
level by indirect addressing
. Many processor and operating system
architectures use vectors
which are also an instance of indirection, being locations which hold the address of a routine to handle a particular event. The event handler can be changed simply by pointing the vector at a new piece of code. C
includes operators "&" which returns the address of a variable
and its inverse "*" which returns the variable at a given address. | <urn:uuid:4638bc37-f1bc-47bc-b376-722b94791a34> | 3.515625 | 160 | Structured Data | Software Dev. | 26.345313 |
I have created a list class, that allows the user to create or edit a text file with a list of information inside the .txt file. When I read into the alphabet.txt (a .txt with a list of all the letters), it prints out the letter "z" twice. The editing that the user does is shown between the two "z's." I'm attaching a picture that explains my dillemna.
Another problem is when I print the contents of the file, it does not print the contents of the entire file.
Thank You in advance.
below is a chunk of my List.cpp file.
cout <<"The following files are available for editing: \n";
cout<< "Name the .txt file that you wish to open\n";
cout << "Below displays the content of the file you selected" << endl << endl;
int response, i;
cout << "Enter the number of entries you would like to edit" << endl;
cin >> response;
cout << endl;
for(i=0; i < response; i++)
cout << "Enter your item" << endl;
cin >> a[i];
myFile << a[i] << endl;
I have created a list class, that allows the user to create or edit a text file with a list of information inside the .txt file. My problem is trying to add the new information into the file without erasing the existing data.
1) Your question is not specific to Visual C++. It is a general C++ issue, which makes it a topic for the Non-Visual C++ forum.
2) How about trying a very simple, 3 or 4 line main() program to experiment how you go about doing this? Once you are familiar with what you need to do in the smaller program, then you apply it to the larger program. Stuff about list classes and whatever else you are doing is not important or even necessary.
3) Please use code tags when posting code.
using namespace std;
ofstream ofile("mytest.txt", ios::app);
if ( ofile )
ofile << "Add another line";
Here is mytest.txt:
This is line 2
This is line 3
Now, given this very simple program, what are the results? If they are not what you want, you work on the program above to get the desired results. Then you take what you've learned in the small program and apply it to the larger program.
What does this accomplish?
1) You learn how to use a facility of the streams library without all of that unnecessary information.
2) You make it easier for others to help you to see what you're doing.
3) If in the remote chance there is a bug in the C++ library, you have a small app to send off to the Visual C++ development team. | <urn:uuid:3fff0456-4c48-4060-986b-97a76eae9aa2> | 2.71875 | 617 | Comment Section | Software Dev. | 72.374791 |
Electricity is a basic feature of the matter that makes up everything in the universe.
Electrical force is responsible for holding together the atoms and molecules from which matter is composed. In this way, electricity determines the structure of every object that exists. Electricity is also associated with many biological processes.
In the human body, electrical signals travel along nerves, carrying information to and from the brain. Electrical signals tell the brain what the eyes see, what the ears hear, and what the fingers feel. Electrical signals from the brain tell muscles to move. Electrical signals even tell the heart when to beat.
One of the most important properties of electricity is electric energy.
During the 1800's, people learned to harness electricity to do work. Inventors and scientists learned how to generate electric energy in large quantities. Inventors and scientist found ways to use that energy to produce light, heat, and motion. They developed electric devices that enabled people to communicate across great distances and to process information quickly. The demand for electric energy grew steadily during the 1900's.
Several thousand years ago, the ancient Greeks observed that a substance called amber attracted bits of lightweight material, such as feathers or straw, after it was rubbed with cloth. Amber is fossilized pitch from pine trees that lived millions of years ago
Amber is a good electric insulator, so it easily holds electric charge. Greeks were experimenting with static electricity when they rubbed amber. The Greek word for amber is electron. The English words electricity and electron come from this word. Greeks, Chinese, and other people, knew of another substance that could attract things. It was a black rock called lodestone or magnetite. Lodestone attracts iron objects, which tend to be heavy. On the contrary, amber attracts only light things, like straw.
In 1551, Italian mathematician Girolamo Cardano, also known as Jerome Cardan, realized that the attracting effects of amber and of magnetite must be different. Cardano was the first to note the difference between electricity and magnetism. In 1600, William Gilbert reported that such materials as glass, sulfur, and wax behaved like amber. When rubbed with cloth, they too attracted light objects. Gilbert called these materials electrics. He studied the behavior of electrics and concluded that their effects must be due to some kind of fluid.
In the 1730's, French scientist Charles Dufay found that charged pieces of glass attracted amber like substances but repelled other glass like substances. Dufay decided that there must be two kinds of electricity's. He called them vitreous (for glass like substances) and resinous (for amber like substances). Dufay had found negative and positive electric charge, though he thought of them as two kinds of "electric fluid."
Benjamin Franklin, an American scientist and statesman, began to experiment with electricity in 1746. Franklin thought that there was only one kind of electric fluid. He theorized that objects with too much fluid would repel each other, but they would attract objects with too little fluid. If an object with an excess of fluid touched an object deficient in fluid, the fluid would be shared. Franklin's idea explained how opposite charges cancel each other out when they come in contact. Franklin used the term positive for what he thought was an excess of electric fluid. He used the term negative for a deficiency of fluid. Franklin didn't know that electricity is not a fluid.
Rather, electricity is associated with the charges of electrons and protons. In 1752, Franklin performed his famous experiment, flying a kit during a thunderstorm. When the kite and the string became electrically charged, Franklin concluded that the storm clouds were themselves charged. He became convinced that lightning was a huge electric spark. Luckily, lightning didn't strike his kite; if the kite were strike by a lightning he would probably have been killed.
In 1767, Joseph Priestley described the mathematical law that shows how attraction weakens as the distance between oppositely charged objects increases. In 1785, Charles Augustin de Coulomb confirmed Priestley's law. Coulomb showed that the law also held the true for the repulsive force between objects with the same charge. The principle is now known as Coulomb's Law.
In 1771, Luigi Galvani found that the leg of a recently killed frog would twitch when touched with two different metals at the same time.
In the late 1790's, Alessandro Volta showed that chemical action occurs in a moist material in contact with two different metals. The chemical action results in an electric current. The flow of current had made Galvani's frog twitch. Volta collected pairs of disks, consisting of one silver and one zinc disk. He separated the pairs with paper or cloth moistened with salt water. By piling up a stack of such disks, Volta constructed the first battery, called a voltaic pile.
German physicist Georg S. Ohm devised a mathematical law to describe the relationship between current, voltage, and resistance for certain materials. According to the Ohm's law a larger voltage can push a larger current through a given resistance. Also, a given voltage can push a larger current through a smaller resistance.
In 1820, Hans C. Oersted found that an electric current flowing near a compass needle will cause the needle to move. Oersted was the first to show a definite connection between electricity and magnetism.
During the 1820's, Andre Marie Ampere discovered the mathematical relationship between currents and magnetic fields. That relationship is now known as Ampere's law. It is one of the basic laws of electromagnetism.
In the early 1830's, Michael Faraday and Joseph Henry independently discovered that moving a magnet near a coil of wire produced an electric current in the wire. Other experiments showed that electrical effects occur any time a magnetic field changes. Audio and videotape recording, computer disks, and electric generators are based on this principle. James Clerk Maxwell combined all the known laws covering electricity and magnetism into a single set of four equations. Maxwell's equations describe completely how electric and magnetic fields arise and interact. Maxwell made a new prediction that a changing electric field would produce a magnetic field. That prediction led him to propose the existence of electromagnetic waves, which we now know include light, radio waves, and X rays.
In the later 1880's, Heinrich R. Hertz showed how to generate the detect radio waves, proving Maxwell correct.
In 1901, Guglielmo Marconi transmitted electromagnetic waves across the Atlantic Ocean, setting the stage for radio, TV, satellite communications, and cellular telephones. G. Johnstone Stoney believed that electric current was actually the movement of extremely small, electrically charged particles. In 1891, Stoney suggested that these particles be called electrons.
In 1897, Joseph John Thomson proved the existence of electrons and showed that all atoms contain them. A research by Robert A. Milikan accurately measured the electron's charge.
Later, scientist found out that electrons can be dislodged from a metal surface in a vacuum tube. A vacuum tube with most of the air removed. The tube contains electrodes with wires that extend through the glass. Linking batteries to the electrodes causes a current of electrons to flow within the tube. Adjusting the voltage can modify the current. Vacuum tubes can amplify, combine, and separate weak electric currents. This invention helped make radio, TV, and other technologies possible.
In 1947, John Bardeen, Walter H. Brattain, and William Shockley invented the transistor. Transistors do the same jobs as vacuum tubes, but they are smaller and more durable, and they use far less energy.
By the 1960's, transistors had replaced vacuum tubes in most electronic equipment. Ever since then, electronics companies have developed ever-smaller transistors. In present time, millions of interconnected transistors fit on a single chip called an integrated circuit. Many scientist hope that new electric devices will actually help curb the growing demand of electric energy.
Computers, for example, can control lights, air conditioning, and heating in buildings to reduce energy use. Compact fluorescent lamps, using miniature electronic circuits, provide the same light as ordinary light bulbs but use only one-fifth as much electric energy. Computer and modern communication systems enable people to work at home and save energy they would have used for transportation. | <urn:uuid:83399a4c-8b5e-473b-bc0a-000236166d70> | 3.796875 | 1,713 | Knowledge Article | Science & Tech. | 42.730956 |
- Ruby Modules are similar to classes in that they hold a collection of methods, constants, and other module and class definitions. Unlike classes, you cannot create objects based on modules; instead, you specify that you want the functionality of a particular module to be added to the functionality of a class, or of a specific object.
- Modules serve two purposes: First they act as namespace, letting you define methods whose names will not clash with those defined elsewhere. Second, they allow you to share functionality between classes - if a class mixes in a module, that module's instance methods become available as if they had been defined in the class. They get mixed in.
- Observe how we use require or load. require and load take strings as their arguments.
require 'motorcycle' or load 'motorcycle.rb'
include takes the name of a module, in the form of a constant, as in include 'Stuff'.
The include method accepts any number of Module objects to mix in:
include Enumerable, Comparable
Although every class is a module, the include method does not allow a class to be included within another class.
- Remember that you can mix in more than one module in a class. However, a class cannot inherit from more than one class.
- Class names tend to be nouns, while module names are often adjectives.
- At every point when your program is running, there is one and only one self - the current or default object accessible to you in your program.
- Please note the rules given for self in the Self related page.
- Java features the ability to serialize objects, letting you store them somewhere and reconstitute them when needed. Ruby calls this kind of serialization marshaling.
- Marshal.dump is used to save a serialized version of an object.
- Marshal.load is used to read in from a serialized object.
- A Ruby constant is a reference to an object.
- Although constants should not be changed, you can modify the internal states of the objects they reference.
- Remember the rules for constants.
Note: The Ruby Logo is Copyright (c) 2006, Yukihiro Matsumoto. I have made extensive references to information, related to Ruby, available in the public domain (wikis and the blogs, articles of various Ruby Gurus), my acknowledgment and thanks to all of them. Much of the material on rubylearning.com and in the course at rubylearning.org is drawn primarily from the Programming Ruby book, available from The Pragmatic Bookshelf. | <urn:uuid:d908edeb-1c6e-4dd5-888d-611480a1d07b> | 3.390625 | 537 | Documentation | Software Dev. | 42.721204 |
Green Computing -- From Fad to Fixture
Green technology, an expansive field that is rooted in finding the balance between nature and man-made processes, encompasses everything from how technological devices are built to how they are destroyed and consume energy in between.
In practical terms, it could mean purchasing energy-efficient products made with recyclable materials. Or it could mean how technology tools are disposed of—researchers estimate 70 to 80 percent of electronic waste ends up in landfills.
Rich Kaestner, who has worked in and around technology for decades, heads the Consortium for School Networking’s green computing initiative, an online clearinghouse of news, tips, and resources for K-12 leaders. He acknowledges talk of green technology has come and gone, but believes it’s finally gaining traction.
“It’s reached its critical mass and become a real issue and not a fad,” he says. “Too many people have recognized something needs to be done.”
Recently, the Government Accountability Office released a scathing report, accusing the Environmental Protection Agency (EPA) of turning a blind eye to the export of old electronics to other countries, which don’t always use safe practices to dismantle the hazardous waste.
Kaestner says surveys have shown that, despite growing awareness, there hasn’t been a lot of incentive for people to take action, particularly in schools.
“The thing that’s holding this back is no one is taking the initiative on this, no one’s taking charge,” he says. “Schools have a responsibility to set an example to the community at large as well as to students. They have a political and ethical responsibility to address green initiatives.”
The tide may be changing, however.
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Subscribers please click here to continue reading. If you are not a subscriber, please click here to purchase this article or to obtain a subscription to ASBJ. | <urn:uuid:07f04fe3-f36d-41a4-89cf-ad58dcca8b07> | 3 | 417 | Truncated | Science & Tech. | 36.158615 |
Removes the first occurrence of the specified item from an Array object. This function is static and can be invoked without creating an instance of the object.
var isRemoved = Array.remove(array, item);
The array to remove item from.
The object to remove from the array at the first occurrence.
true if the specified item exists as element in the array and was removed; otherwise, false.
Use the remove function to remove the first occurrence of a specified item from an array. The index value of items that remain in the array is decreased by one.
In Mozilla Firefox, calling the remove function with item set to undefined removes the first item with that value from the array. In other browsers, calling the function with item set to undefined has no effect.
The following example shows how to use the remove function to remove the first occurrence of an item from an array.
var a = ['a', 'b', 'c', 'd', 'e'];
// View the results: "a,b,d,e"
// View the results: "a,b,e" | <urn:uuid:1b38a16f-6e86-40ac-aceb-d21e3ad0577a> | 3.109375 | 229 | Documentation | Software Dev. | 52.968928 |
Wildlife of the Mongolian Steppe
Dr. Richard Reading from the Denver Zoo has created a model ecosystem management program through his interest of argali, the largest mountain sheep in the world. These sheep have been listed as a near threatened species, and reside in the highlands of central Asia. With the help of Earthwatch volunteers, Dr. Reading has been able to collect data on argali along with countless other species such as Siberian ibex, vultures, kestrels, small mammals, lizards, and insects.
Dr. Reading has collaborated with local Mongolian students and scientists to track many of these species in the Ikh Nart Nature Reserve, Gun Galuut Nature Reserve, and other parts of the Mongolian Steppe. With the use of radio tags he can gather data on location, reproduction, and mortality of individuals over a number of months. This data has lead to numerous conservation programs to preserve the biodiversity of this ecosystem.
The United Nations Development Programme rated the Ikh Nart Nature Reserve as the best managed reserve in Mongolia and will use it as a model for other parks in the region. This program has provided positive results with an increase in argali populations and an increase in overall biodiversity. The preservation of this unique ecosystem will create a healthy environment for plants, animals and humans.
Earthwatch Institute Website | <urn:uuid:670a0a7f-3c17-41bc-89a3-16958d75f1c7> | 3.3125 | 273 | Knowledge Article | Science & Tech. | 34.563305 |
Charles David Keeling's measurements provided the first significant evidence of increasing atmospheric carbon dioxide concentration in the atmosphere.
A snapshot of how 2012 stacks up against the five other warmest years ever recorded in the U.S.
If it seems like autumn leaves are taking longer to change color, you’re not imagining things. Over the past 25 years, the onset of autumn has shifted.
As the graphic shows, people cause most wildfires. But lightning-ignited fires burn by far the most territory.
You knew it was warm last month, but today it’s official: it wasn’t just warm; it was the warmest March ever recorded in the U.S.
Online searches for the word “pollen†have gone through the roof this spring, and if you know anyone with seasonal allergies (and who doesn't?) this isn’t surprising.
The Lower 48 as a whole had an average shift of “first leaf†from March 20 (1951-1980 average) to March 17 now (1981-2010 average) – approximately 3 days earlier.
A graphical look at the way winters have changed in the United States between 1895 and 2010. | <urn:uuid:917c1780-84b1-4a27-8bf4-613d8680fe09> | 3.390625 | 287 | Content Listing | Science & Tech. | 76.64699 |
The El Niño – Southern Oscillation (ENSO) is a recurring climate pattern involving changes in the temperature of waters in the central and eastern tropical Pacific Ocean. On periods ranging from about three to seven years, the surface waters across a large swath of the tropical Pacific Ocean warm or cool by anywhere from 1°C to 3°C, compared to normal. This oscillating warming and cooling pattern, referred to as the ENSO cycle, directly affects rainfall distribution in the tropics and can have a strong influence on weather across the United States and other parts of the world. El Niño and La Niña are the extreme phases of the ENSO cycle; between these two phases is a third phase called ENSO-neutral.
El Niño conditions occur when abnormally warm waters accumulate in tropical latitudes of the central and eastern Pacific Ocean. Consequently, tropical rains that usually fall over Indonesia shift eastward. During El Niño winters, northwestern North America is more likely to experience warmer-than average temperatures and the southeastern U.S. is more likely to receive more rain than average.
La Niña conditions occur when cooler-than-average waters accumulate in the central and eastern tropical Pacific and tropical rains shift to the west. In the United States, seasonal precipitation impacts are generally opposite those of El Niño. Compared with El Niño conditions, La Niña conditions are generally more favorable for the formation of Atlantic hurricanes.
How do we tell what phase ENSO is in?
NOAA’s Climate Prediction Center has determined the average monthly sea surface temperature for a particular swath of the tropical Pacific Ocean by averaging measurements collected there over the past 30 years. Scientists refer to that swath as the Niño 3.4 region. The observed difference from the average temperature in that region—whether warmer or cooler—is used to indicate the current phase of ENSO.
The shaded rectangle shows the Niño 3.4 region, the area of the Pacific Ocean where observed sea surface temperature is compared to average sea surface temperature to calculate the Oceanic Niño Index. The region spans a swath from 5ºN to 5ºS latitude and 120ºW to 170ºW longitude.
To filter out month-to-month variability, average sea surface temperature in the Niño 3.4 region is calculated for each month, and then averaged with values from the previous month and following month. This running three-month average value is compared with average sea surface temperature for the same three months during 1971 – 2000. The departure from the 30-year average of the three-month average is known as the Oceanic Niño Index or ONI.
Explore this interactive graph: Click and drag to display different parts of the graph. To squeeze or stretch the graph in either direction, hold your Shift key down, then click and drag.
This graph shows monthly values of the Oceanic Niño Index from 1950 through present.
For real-time monitoring and prediction, NOAA considers El Niño conditions to be present when the Oceanic Niño Index is at least +0.5. In other words, El Niño conditions exist when the three-month average sea surface temperature in the Niño 3.4 region is at least 0.5°C warmer than average.
Conversely, NOAA declares that La Niña conditions exist when the Oceanic Niño Index is less than -0.5. This means that the three-month sea surface temperature in the Niño 3.4 region is at least 0.5°C cooler than average.
Whenever the Oceanic Niño Index is between +0.5 and -0.5, conditions are ENSO-neutral. A table of ONI values for each three-month period from 1950 to present is available from NOAA’s Climate Prediction Center.
Climate Prediction Center’s ENSO Cycle Page, Accessed December 10, 2009.
El Niño Theme Page, NOAA’s Pacific Marine Environmental Laboratory. Accessed October 2, 2009.
ENSO Web, International Research Institute for Cimate and Society. Accessed October 2, 2009. | <urn:uuid:17fa6db8-3793-43e0-9c8f-c39ae06ba5a3> | 4.34375 | 823 | Knowledge Article | Science & Tech. | 44.548385 |
An Overview of the Base Plot Function in R
The base graphics function to create a plot in R is simply called plot(). This powerful function has many options and arguments to control all kinds of things, such as the plot type, line colors, labels, and titles.
The plot() function is a generic function and R dispatches the call to the appropriate method. For example, if you make a scatterplot, R dispatches the call to plot.default(). The plot.default() function itself is reasonably simple and affects only the major look of the plot region and the type of plotting. All the other arguments that you pass to plot(), like colors, are used in internal functions that plot.default() simply happens to call.
To get started with plot, you need a set of data to work with. One of the built-in datasets is islands, which contains data about the surface area of the continents and some large islands on Earth.
First, create a subset of the ten largest islands in this dataset. There are many ways of doing this, but the following line of code sorts islands in decreasing order and then uses the head() function to retrieve only the first ten elements:
> large.islands <- head(sort(islands, decreasing=TRUE), 10)
It is easy to create a plot with informative labels and titles. Try the following:
> plot(large.islands, main="Land area of continents and islands", + ylab="Land area in square miles") > text(large.islands, labels=names(large.islands), adj=c(0.5, 1))
How does this work? The first line creates the basic plot with plot() and adds a main title and y-axis label. The second line adds text labels with the text(). | <urn:uuid:dcee4b10-13af-4f3f-b8a4-482cb1bda4ad> | 4.3125 | 372 | Tutorial | Software Dev. | 67.294883 |
Watson constructing base pair models
During the process of trying to elucidate the structure of DNA, Jim Watson made some cardboard models to try to understand how DNA nucleotides are paired. It helped him visualize how hydrogen atoms of paired nucleotides interact with each other to form a symmetrical structure that fits the double helix model.
1 minute 42 seconds
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Biologists from the University of the Ryukyus in Okinawa, Japan, have found two new species of encrusting anemones, in unexpected locations.
The species belong to the genus Neozoanthus, which was previously known only from a single species in the Indian Ocean. Surprisingly, the new species were found in the Pacific Ocean, in southern Japan and on the Great Barrier Reef, Australia.
The only previous species of Neozoanthus was described in 1972 from Madagascar, and subsequently it was not seen for almost 40 years, until recent research had ascertained that new Pacific specimens likely belonged to Neozoanthus.
The members of the Neozoanthus genus are small, with individual polyps no more than 6 mm in diameter, and have red, gray, blue or purple oral discs; all inhabit coral reef ecosystems in areas with strong currents and some siltation. Both new species and the species from Madagascar contain symbiotic, photosynthetic, single-celled algae that can provide them with energy from the Sun.
“We were very surprised in 2008 to discover Neozoanthus in the Pacific, in Japan, and initially thought that perhaps these were very rare,” said Prof James Davis Reimer, lead author of a paper reporting both new species in the journal ZooKeys.
However, further research in southern Japan revealed that the Japanese species was locally common. A further surprise came during the Census of Marine Life’s Census of Coral Reef Ecosystems surveys on the Great Barrier Reef in 2009 and 2010, when similar encrusting anemones were found thousands of kilometers away from both Madagascar and Japan.
“These findings can be explained by the fact that there are very few zoanthid researchers in the world. These species are not particularly hard to find, but there was no one looking for them,” Prof Reimer said. “This research demonstrates how little we know about marine biodiversity, even in regions relatively well researched.”
Bibliographic information: Reimer JD et al. 2012. Two new species of Neozoanthus (Cnidaria, Hexacorallia, Zoantharia) from the Pacific. ZooKeys 246: 69; doi: 10.3897/zookeys.246.3886 | <urn:uuid:f0978f8a-19ce-4476-8145-e96187a2dbbd> | 2.96875 | 472 | Knowledge Article | Science & Tech. | 40.968006 |
January 1, 2010
The main ingredient in clown makeup is being used to create a nano-material that could protect astronauts from solar radiation.
BOB HIRSHON (Host):
Can clown makeup protect astronauts? I’m Bob Hirshon and this is Science Update.
Boron nitride is used to make clown makeup. Now it’s being spun into microscopically fine, super-strong fibers that could be used for bulletproof vests and even spaceships. Michael Smith is staff scientist at NASA’s Langley Research Center. He says astronauts going on long trips through space need to be protected from solar radiation.
MICHAEL SMITH (NASA Langley Research Center):
Boron is a perfect natural absorber of the thermal neutrons that will go through you body and turn your DNA into something else that you don’t want it to be.
The fibers are produced using a high energy laser at Jefferson Laboratory in Hampton, VA and spun into a super strong yarn. Smith thinks the nanotubes have countless uses.
It’s really a root technology. You’ve got our iron age your copper age—this could spawn a new age.
But first they’ll have to scale up production to make the fibers commercially viable. I’m Bob Hirshon for AAAS, the science society. | <urn:uuid:8f42a65c-2f31-488c-9352-da2afbd722b2> | 2.96875 | 285 | Truncated | Science & Tech. | 60.380962 |
Click on the images for larger versions
Hector's Dolphin (Cephalorhynchus
Credit & Copyright: Dr. Bruce G.
Explanation: Here is one of the smallest and rarest of all cetaceans ... the Hector's dolphin of New Zealand.
Hector's dolphins grow to less than 1.4 m (4.8 feet) long, and are found only in the waters around New Zealand. Their low, rounded, notched dorsal fin is characteristic.
Photographing these individuals was a challenge. Hector's dolphins seldom leap from the water like other dolphins, and hardly break the water surface when they arise to breath (like all cetaceans, they are marine mammals and must breath air).
Despite its highly restricted distribution around New Zealand, the species seems relatively secure thanks to protection in marine sanctuaries such as around Banks Peninsula on South Island.
dolphins are poorly studied and little is known of their biology and
ecology. They sometimes occur in groups, seem to remain in local areas
rather than migrate, and seem to favor river mouths with muddy
Next week's picture: Black-shouldered Kite
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A very large solar flare erupted on the Sun yesterday and the Coronal Mass Ejection (CME) is speeding toward the Earth right now. It is expected to arrive early Saturday morning (4:30am MDT + / – 7 hours) and if you can get away from the city lights, even northern Colorado has a chance to see the heightened aurorae. Here is some good background info on solar flares and CMEs from NASA.
- NOAA OVATION Auroral Forecast
- Auroral Activity Extrapolated from NOAA POES
- ThorntonWeather.com Space Weather page
Space weather starts at the Sun. It begins with an eruption such as a huge burst of light and radiation called a solar flare or a gigantic cloud of solar material called a coronal mass ejection (CME). But the effects of those eruptions happen at Earth, or at least near-Earth space. Scientists monitor several kinds of space “weather” events — geomagnetic storms, solar radiation storms, and radio blackouts – all caused by these immense explosions on the Sun.
One of the most common forms of space weather, a geomagnetic storm refers to any time Earth’s magnetic environment, the magnetosphere, undergoes sudden and repeated change. This is a time when magnetic fields continually re-align and energy dances quickly from one area to another.
- Keep a watchful eye on the sun: Check out ThorntonWeather.com’s Space Weather page
Geomagnetic storms occur when certain types of CMEs connect up with the outside of the magnetosphere for an extended period of time. The solar material in a CME travels with its own set of magnetic fields. If the fields point northward, they align with the magnetosphere’s own fields and the energy and particles simply slide around Earth, causing little change. But if the magnetic fields point southward, in the opposite direction of Earth’s fields, the effects can be dramatic. The sun’s magnetic fields peel back the outermost layers of Earth’s fields changing the whole shape of the magnetosphere. This is the initial phase of a geomagnetic storm.
The next phase, the main phase, can last hours to days, as charged particles sweeping into the magnetosphere accumulate more energy and more speed. These particles penetrate closer and closer to the planet. During this phase viewers on Earth may see bright aurora at lower latitudes than usual. The increase – and lower altitude – of radiation can also damage satellites traveling around Earth.
The final stage of a geomagnetic storm lasts a few days as the magnetosphere returns to its original state.
Geomagnetic storms do not always require a CME. Mild storms can also be caused by something called a corotating interaction region (CIR). These intense magnetic regions form when high-speed solar winds overtake slower ones, thus creating complicated patterns of fluctuating magnetic fields. These, too, can interact with the edges of Earth’s magnetosphere and create weak to moderate geomagnetic storms.
Geomagnetic storms are measured by ground-based instruments that observe how much the horizontal component of Earth’s magnetic field varies. Based on this measurement, the storms are categorized from G1 (minor) to G5 (extreme). In the most extreme cases transformers in power grids may be damaged, spacecraft operation and satellite tracking can be hindered, high frequency radio propagation and satellite navigation systems can be blocked, and auroras may appear much further south than normal.
Solar Radiation Storms
A solar radiation storm, which is also sometimes called a solar energetic particle (SEP) event, is much what it sounds like: an intense inflow of radiation from the sun. Both CME’s and solar flares can carry such radiation, made up of protons and other charged particles. The radiation is blocked by the magnetosphere and atmosphere, so cannot reach humans on Earth. Such a storm could, however, harm humans traveling from Earth to the moon or Mars, though it has little to no effect on airplane passengers or astronauts within Earth’s magnetosphere. Solar radiation storms can also disturb the regions through which high frequency radio communications travel. Therefore, during a solar radiation storm, airplanes traveling routes near the poles – which cannot use GPS, but rely exclusively on radio communications – may be re-routed.
Solar radiation storms are rated on a scale from S1 (minor) to S5 (extreme), determined by how many very energetic, fast solar particles move through a given space in the atmosphere. At their most extreme, solar radiation storms can cause complete high frequency radio blackouts, damage to electronics, memory and imaging systems on satellites, and radiation poisoning to astronauts outside of Earth’s magnetosphere.
Radio blackouts occur when the strong, sudden burst of x-rays from a solar flare hits Earth’s atmosphere, jamming both high and low frequency radio signals. The X-rays disturb a layer of Earth’s atmosphere known as the ionosphere, through which radio waves travel. The constant changes in the ionosphere change the paths of the radio waves as they move, thus degrading the information they carry. This affects both high and low frequency radio waves alike. The loss of low frequency radio communication causes GPS measurements to be off by feet to miles, and can also affect the applications that govern satellite positioning.
Radio blackouts are rated on a scale from R1 (minor) to R5 (extreme). The strongest radio blackouts can result in no radio communication and faulty GPS for hours at a time. | <urn:uuid:fa873ad3-547a-41b1-9781-50c947cea4cd> | 3.484375 | 1,149 | Knowledge Article | Science & Tech. | 40.11059 |
When the students have an understanding of the planet Mars
and some of the problems associated with sending people on extended duration
missions over large distances, they will be guided through discussions in which
they will plan their own mission. They are provided with both weight and monetary
constraints and guidelines as to the cost and weight of mission elements, and
asked to draw up a mission plan that best satisfies their mission aims. The
results of their missions will then be presented to the rest of the class, and
the details put on the team web pages.
The Mission Planning module can be used as the concluding part of the whole Mars in the Classroom project, or as a stand alone practical. It should be noted, however, that a certain amount of prior knowledge (such as some idea of what the globe of Mars looks like and a broad understanding of planetary subjects such as impact cratering, volcanoes and geological vocabulary) is assumed. The project will take about two hours and is entirely paper based. This is another reason why it is best run after a series of practicals, so that the students can apply what they have learned experimentally to an abstract, 'pen and paper' exercise.
This experiment requires some knowledge of the planet Mars and Mars exploration. You can find out more about these things from our Mars information web pages. | <urn:uuid:7294aaaa-538e-42ef-adcb-2431744ccb07> | 4.1875 | 273 | Tutorial | Science & Tech. | 43.783462 |
Meteorologists use radar
tornadoes might form
But, the radar can't detect actual tornadoes. People are needed to do that.
The National Weather Service can't rely on tornado reports from people off
the street. These people don't have any training so they may not actually
see what they think they see. Instead, the Weather Service offers classes
that anyone can take to become part of SKYWARN, a network of trained
volunteer spotters. Meteorologists can feel confident about the accuracy
of the spotter reports. If a tornado is spotted, they can issue a
tornado warning with a good degree of confidence.
Storm spotters are different that storm chasers
in organized networks to observe and confirm severe weather events for
the NWS and for local emergency managers. They also only operate in a
limited area, usually their county.
Shop Windows to the Universe Science Store!Cool It!
is the new card game from the Union of Concerned Scientists that teaches kids about the choices we have when it comes to climate change—and how policy and technology decisions made today will matter. Cool It! is available in our online store
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This just released image shows an X-ray view from the orbiting Chandra X-ray observatory overlaid on a visible light image of galaxy cluster Abell 520 The optical part shows stars in our Milky Way and galaxies belonging to the cluster. The red glow is the x-rays from normal matter heated to millions of degrees in the cluster. The blue denotes the location of the dark matter in the cluster, inferred by its distortion of the coordinates of background galaxies.
Paradoxically, more dark matter appears near the center of the cluster, where galaxies are few , while some areas where there are lots of galaxies show little dark matter.
This is antithetic to what theory predicts- astronomers are baffled that the collision of the Abell 520 cluster tore galaxies away from both dark
matter (blue) and the x-ray emitting hot gas clouds (magenta). The circles show where
astronomers had expected the galaxies to end up.
Credit: NASA/CXC/M. Weiss | <urn:uuid:a9492052-b900-49fe-86a7-62f936603654> | 3.453125 | 202 | Personal Blog | Science & Tech. | 46.000556 |
800,000 years ago the sky over Asia was aflame with teardrops of molten earth, blasted heavenward by a gigantic meteorite impact. Members of Homo erectus, a precursor to modern humans, must have seen the firestorm and gone running for shelter.
What lit the terrified eyes of our distant ancestors were splatters of liquified rock catapulted high into the atmosphere immediately after the impact. This fiery rain cooled and solidified into wondrous and diverse forms as it fell back to Earth as the black rocks we know today as tektites.
Scientists still don’t know where the impact occurred, but it left a huge butterfly pattern of tektites spread across China, southeast Asia and southern Australia.
Tektites are not meteorites but rather Earth rocks that were liquified by the heat and pressure of impact and launched into the atmosphere, even as far as nearby outer space. They’re essentially local rock converted to glass.
Tektites resemble volcanic obsidian, that shiny black glass you find in mineral shops, but they’re a very different material. Composed mostly of silica, commonly found in nature as sand or quartz, the extreme heat they experienced, combined with passage through the rarefied upper atmosphere, have made tektites one of the driest materials found on Earth. Some tektites contain minute amounts of the original meteorite, but what really catches your eye are their shapes and textures.
As the cooling but still plastic blobs fell back through the lower atmosphere, they were deformed by friction with the air into a variety of different shapes depending upon their spin. Spheres or balls formed from material spinning evenly in all directions. Blobs spinning or rotating in just two directions or axes stretched to produce oval-shaped tektites. Ovals were further stretched into dumbbells, and dumbbells snapped apart to create pairs of elongated teardrops. Click HERE for a great illustration of how tektite shapes form.
Tektites ejected to great height at distances of 2,500 to 3,700 miles from ground zero had enough time to solidify. Falling back to Earth they melted again to produce exquisite little buttons surrounded by circular flanges. These rare forms are typically found in Australia far from the center of what’s known as the Australasian tektite strewfield.
Tektites developed fine cracks as they cooled upon reentry which were later enlarged into zillions of pits and grooves through interaction with water and soil in a process called chemical etching. They give these shiny rocks lots of character. Some tektites have smooth sides from material that flaked off after they cooled.
While the Australasian tektites are the most recent and largest strewnfield, there are several other major tektite localities both with and without associated craters:
* North American strewnfield with tektites primarily found in the southeastern states and in Texas. Source: Chesapeake Bay Crater impact 34 million years ago
* European strewnfield famous for the green glass called moldavite, the most colorful of the tektites. Source: Ries Crater impact in Germany 15 million years ago
* Ivory Coast strewnfield originating from the Lake Bosumtwi Crater impact in Ghana 1 million years ago
* A new strewnfield recently discovered in Belize
The most common tektites are those from China and southeast Asia. You’ll find several online sites offering them for sale. One of the best is The Tektite Source run by Norm and Cookie Lehrman. eBay has many dozens for sale every day.
A broken or chipped tektite will help you appreciate both their glassy quality and color. Some are translucent enough to show shades of brown and olive green. All of them have a certain enigmatic aspect. I like to pick one up, turn it in my hand and try to fathom the origin of this or that feature.
It used to be thought that tektites might have been blasted off the moon during a lunar impact or even volcanically, but their earthly composition, traces of meteoric materials and association with craters on Earth connect them to catastrophic events right here at home. To learn more about these cool rocks, I recommend a visit to Aubrey Whymark’s tektite site. | <urn:uuid:d639dfa0-20e4-4876-98e7-073e0dcb78fc> | 4.03125 | 901 | Personal Blog | Science & Tech. | 39.110826 |
|Big Bang Nucleosynthesis|
Every object you've ever seen in your entire life - your TV, your books, your own body - is built up of three simple ingredients: protons, neutrons, and electrons. These three particles even make up the objects we see shining in the daytime and nighttime skies - the sun, the moon, the planets, and the stars. In fact, they are the primary constituents of all visible matter.
Modern cosmology and astrophysics, however, tell us something pretty remarkable - these three particles are not the main constituents of the universe we live in! The universe as a whole is made almost entirely out of mysterious stuff that no one has ever seen before, stuff that we call "dark matter" and "dark energy". The protons, neutrons, and electrons that dominate the world we see around us are just the glittery icing on a vast universe of darkness.
Our current picture of the "energy budget" of the universe is described in the pie chart at left. About 70% of the mass of the universe is believed to be composed of "dark energy", a mysterious substance or energy field that seems to permeate the universe, causing its expansion to speed up over time. Something like 25% is composed of "dark matter" - some sort of stuff that (like ordinary matter) clumps together under its own gravity, but is somehow invisible to us. Finally, the remaining 5% or so is ordinary matter - stars, planets, gas, dust, and all the rest.
This sounds like a crazy idea, but there are actually many good reasons to believe that it's true! See below for a tour of some of the arguments that have convinced many scientists that the universe is more than meets the eye.
One way to look for dark matter is to "simply" count up the total amount of matter and compare it to the total amount of visible matter - if the two don't agree, their must be dark matter! Astronomers can "count" the amount of visible matter using the total amount of light coming from the galaxy (this isn't as easy as it sounds, but we won't get into that here). To do the comparison, you need to find some way to independently estimate the total amount of matter, visible and invisible. Two major methods are described below.
Another way to study the amount of dark matter is to study its effects on the universe's early history and evolution. By finding windows onto the state of the universe shortly after its birth, we can study how it has grown and changed since then. Dark matter has had major effects on the development and bahavior of the universe, and by studying these phenomena we can estimate how much dark matter there is and - perhaps more importantly - what properties it might have.
In science we must always consider the possibility that we are wrong. Dark matter explains our observations exceedingly well, but it's important to consider other options and devise ways of comparing their predictions to those of dark matter theories.
Last updated April 28, 2007 | <urn:uuid:b0666a78-b6d9-4e3b-8fff-e0fab7761e65> | 3.765625 | 619 | Knowledge Article | Science & Tech. | 43.734857 |
Many species of fish are occasional vagrants to British
waters, especially some pelagic species that are brought to our
shores by oceanographic currents.
Luvarus imperialis is a tuna-like fish that is the only
member of its family (Luvaridae). It is an oceanic species that
feeds on gelatinous zooplankton and can grow to nearly 2 m in
length. They are rare vagrants to British waters.
Pilot fish: Naucrates ductor is a
pelagic and oceanic species that associates with sharks, whales,
sea turtles and even boats. Occasional vagrants are captured in the
south-western waters of the British Isles.
Pteroplatytrygon violacea is a little-known stingray that
is often captured in pelagic longline fisheries targeting tuna and
tuna-like species in high seas fisheries. In recent years they have
been reported south-west of Ireland, and two specimens have been
captured in the North Sea.
Identifying unusual fish
If you find or catch an unusual fish, perhaps one you don't
recognise, please provide:
- where you found the fish (latitude and
- how you caught it (if applicable)
- when you found or caught the fish
- the size of the fish
- a photo of the fish, or a general
description (if the fish is not one that you
- any other information that you think might be relevant or
Then contact Cefas scientist, Jim Ellis. He will try to
identify the species from the information provided. In addition,
your information could be help us to build up a more comprehensive
picture of the life in UK waters. | <urn:uuid:641e3f2c-e035-44cd-a1fb-37581ec34b8d> | 3.3125 | 364 | Knowledge Article | Science & Tech. | 40.706601 |
Chapter 12 - Thrusting Against the Quantum Vacuum
Notes by David A Roffman on Chapter 12 of
FRONTIERS IN PROPULSION SCIENCE
Chapter by G. Jordan Maclay (Proffesor Emeritus, University of Illinois),
Quantum Fields LLC, Richland Center, Wisconsin
Chapter 12 explores how quantum vacuum properties may be applied to propulsion. Quantum electrodynamics (QED) is a theory of how light and matter interact (the photon is the force exchange particle for electromagnetism). It has been verified to 1 to 10 billion. QED predicts that the quantum vacuum (the lowest state of the electromagnetic field) holds a fluctuating virtual photon field. Although vacuum is everywhere, currently very little force can be derived from it.
Most efforts in this area revolve around Casimir forces, which arise due to quantum fluctuations. These forces have recently been used in microelectromechanical systems. The chapter will consider spacecraft that use the vacuum for hypothetical possibilities, not engineering feasibilities. To have effective propulsion, breakthroughs in material, methods, and understanding will be necessary. There are no simple ways to mathematically understand how to achieve success.
The field of quantum mechanics is the key to understanding Casimir forces. This area states that the lowest state is that of the quantum vacuum. Particles and light are both quantized fields that are fully relativistic. Any number of photons can exist, and can be easily transformed into coordinate systems (called Lorentz transformations). In the vacuum, pairs of particles (photons, electron-positron pairs, etc.) appear and disappear instantaneously (virtual pairs). Fluctuating electromagnetic fields, which composed the vacuum, are quantized. The vacuum is similar to Heisenberg’s Uncertainty Principle, where momentum and position continually oscillate in certainty. Note: Heisenberg’s Uncertainty Principle ΔP*Δx ≥
h/2 where ΔP is the uncertainty in the momentum and Δx is the uncertainty of the position. In the lowest state, the oscillator is still vibrating, with an energy ½ hω. The Δx and ΔP are actually standard deviations.
A zero-point electromagnetic field is an isotropic fluctuating electromagnetic field that occurs in a particle field, and is present everywhere at zero K with all electromagnetic sources removed. Fluctuations affect all things in the universe. This energy comes from virtual photons of energy. For the quantum vacuum, frequencies that correspond to less than 10-34 m (Planck length) are ignored. Energy is predicted to exist in the 10114 J/m3 range. However, real results have shown it to be hundreds of orders of magnitude less. This is the greatest discrepancy in scientific history. Some solutions to this cosmological constant problem have been renormalization, super-symmetry, string theory, and quintessence. In this system, real photons have less energy than virtual photons.
Casimir forces were predicted by Heindrick Casimir in 1948. An important note is that modes with frequencies greater than the plasma frequency aren’t really affected by metal surfaces due to transparency of metal at those levels. To not have infinite quantities, the finite change in energy of the vacuum due to surfaces must be computed. These forces can act differently for differently shaped formations. For a cube or sphere, Casimir forces jut outward. However, for a rectangular cavity, the forces may be outward, inward, or zero. For application to space travel, it is hoped that by transferring energy (arising from radiation pressure) from virtual photons to surfaces, net propulsion can be generated.
The dynamic Casimir effect has parallel plates that should move rapidly, and that can cause an excited state of the vacuum between the plates (this causes the creation of real photons). Unfortunately, this has yet to be observed through experimentation. A vibrating mirror could be used here for space propulsion.
Even though the Casimir effect is well known, there are still alternative explanations. The observed effects could just be derivatives of Van der Waals forces. They could also be interpreted in terms of source fields.
Despite all of our knowledge, this field, like many others, has limitations on what can be calculated. Parallel plate geometry (almost sphere-flat plate geometry) has been the only for which results have been calculated. Other surfaces are too difficult to calculate. Right angles provide a real source of trouble. Properties of binding energies are typically ignored.
The force wasn’t accurately measured until 1998. Typically measurements are made by having one surface flat, and the other curved. Recent work has confirmed effects and predictions for finite conductivity, surface roughness, temperature, and uncertainty in dielectric functions.
Parallel plate Casimir forces result in an inverse fourth power relationship as the plates change in distance for conducting surfaces. The sticking of micromachined membranes to each other may be caused by these forces. However, for semiconductor surfaces, the equation for force is more complicated. For this situation, it is possible to tune plasma frequency by light, temperature, or voltage. Arnold et al. were able to see an increase in Casimir forces due to light. This has yet to be repeated though.
As for space propulsion, it is possible, but is not efficient. An important fact in this area is that if vacuum energy is independent of craft position, then energy and momentum are constant. The space ship mentioned in the book is that of quantum sails. One would think symmetry of radiation pressure must be broken. Equal virtual photon impacts on both sides of a sail will produce no net force. Different materials on each side of the sail will make no difference. Temperature gradients may, however, may cause a force to be exerted. Invariance of zero-point fluctuations is a precept of the quantum vacuum. If this didn’t exist, then it would be possible to find a universal rest frame for the universe. But if that were true, then special relativity would be false. While it would seem that thermal effects could generate propulsion, causality may throw this pleasant result out. The real question is how to remove energy from the vacuum.
There have been ideas about using negative vacuum energy density to assist in propulsion. This would make negative mass (or so it is hoped). As discussed in earlier chapters, this has repulsive properties, and could provide endless propulsion. However, there has been no negative vacuum energy density ever produced (it is always positive). If success occurs, then it may also be possible to generate wormholes. It may be possible to reduce mass through this approach.
A dynamic system is another possibility for propulsion. The vibrating mirror is one such approach. A mirror is powered to generate radiation. Such a rate of vibration starts at zero, increases, and then returns to zero. The book considers ideal conditions, and efficiency. All photons produced are assumed to fly off in one direction (and not all the over the place). Efficiency is still very low, with a momentum to energy ratio of about 1/c (the speed of light). The following are ignored in this setup: mass change in the craft, radiative mass shifts, fluctuations and divergence issues, and dissipative force that made the mirror vibrate. Based on the dynamic Casimir effect and known science, 10-5 photons will emitted per second.
Chapter 12 goes further by proposing a craft that relies 100% on the quantum vacuum. The motor that would power the mirrors could be run off quantum energy. Quantum energy could be collected via perfectly conducting (uncharged) parallel plates. Casimir forces would do work on the plates, and with a reversible isothermal process, success could achieved (mirrors would accelerate). A best-case result of such a rocket would peak at 8 m/s. This is about 103 fold less than a chemical rocket. While propulsion is possible, an assistive power source would be a good idea to have.
Mirrors could produce a velocity 3 x 10-20 m/s2. This is inefficient and slow. Not all hope is lost, as the chapter provides ideas to increase acceleration. A typical response to this problem is to use the dynamic Casimir effect, which hasn’t been proven yet. In 1994, it was predicted (by Law) that a resonant response of the vacuum to an oscillating mirror in a one-dimensional cavity would occur.
If the oscillation frequency is equal to the odd integer multiple of the fundamental optical resonance frequency, then (for the GHz range) it possible to increase acceleration of the theoretical craft by a factor 109 (to 3 x 10-11). By raising temperature of a 1cm cavity to 290K, it is possible to provide another increase of 103. This means that after ten years, a velocity of 10m/s is reached (three orders of magnitude less than voyager).
Results are very dependent upon assumptions. The book used plate mass/area and systems liberally. However, for the oscillation amplitudes, conservative estimates were used. To create large amplitudes (for oscillation) it may be necessary to use carbon-nanotubes. Another approach is creating a large gradient of an index of refraction using a plasma front. When the gas and the semiconductor in this approach are viewed, the acceleration of the mirror can be 1020 m/s2. There will be Fourier components, and there is still much work to be done in this area. It may also be possible to focus the fluctuations of the vacuum electromagnetic field.
While all this may seem to be great, there is still too much unknown in physics. We still cannot magnify Casimir forces to the macroscopic levels. Complex geometries and facts of interest from them are still all in the dark. There is no consensus for the general outlook and the effects of materials. Numerous tests are needed to find closure on negative mass claims and the dynamic Casimir effect. The only real use of Casimir forces has been in micro and nano-electromechanical systems. There are more possibilities to be discovered here, including quantum torque. Only time will tell if success waits, but miniaturization and progress are expected. | <urn:uuid:df0f2542-0935-4208-a249-8e6919b1e4ac> | 3.3125 | 2,093 | Academic Writing | Science & Tech. | 40.572253 |
Most bioluminescent ocean dwellers produce blue-green light, because its wavelengths travel farthest in the water. Because this applies to the sun's light too, marine life tends to have eyes that are only sensitive to a small range of blue-green light. Black Dragonfish, as well as the rest of the the Malacosteid family, produces deep red light as well, and has a novel way of sensing its reflection.
Using red light is obviously advantageous because of other fish's inability to see it. That is, if the Black Dragonfish is using its red bioluminescence to find prey, the prey won't be able to see it coming and escape. While the Black Dragonfish is able to produce the usual blue-green light through a separately evolved organ, it's theorized that it's only used for mating and warning, while the red light is used for hunting.
Production of the red light is pretty interesting, and involves fluorescence, sort of like a natural black light tube (only producing very long wavelength light instead of very short). Light produced in the Dragonfish's photophore, the light-bearing organ, is of a pretty short wavelength, sort of a bright orange. It is absorbed by fluorescent pigments inside the photophore, and re-emitted at a much longer, and thus redder, wavelength. Additionally, there is a filter over the photophore that lets only the longest waves through, creating the Dragonfish's near infra-red luminescence.
The way the Black Dragonfish senses reflected red light is also cool. Its eyes are like those of most other fish, and only able to see the blue-green wavelengths of light. Its eyes use a visual pigment chemically related to chlorophyll, which turns the red photons into electricity that directly stimulates the blue-green sensitive nerves. The special pigment is commonly referred to as an antenna pigment because of the nature of its operation, turning the signal into electricity instead of a chemical neurotransmitter of some kind. | <urn:uuid:2e52e692-2882-445d-a388-5d318b8ab84c> | 3.78125 | 416 | Knowledge Article | Science & Tech. | 40.474358 |
Today was a relatively calm day as we continued to collect gravity, magnetic, and bathymetric data in the southwest corner of the region. For most of today we were traveling in a northwest direction and consequently were going with the current. This meant that we had pretty smooth sailing!
One of the computer screens we monitor 24/7 includes sonar data from the MR1 we are towing behind the ship. The MR1 sends a sound wave to the sea floor, and depending on how hard the surface is, the sound waves are received back at different times. Highly reflective hard surfaces show up black whereas more sedimented areas (less reflective) show up lighter in color. We will use these data to determine where the best places to dredge will be. An example of these images is included below. The black areas are hard fresh edges of lava flows, whereas the lighter areas indicate flat sedimented features.
The map below shows the course we have been following. As we "mow the lawn" and travel back and forth along these lines we collect bathymetric and sonar data of the sea floor, creating much more detailed maps than have ever been made for this area. We have been finding many new and interesting features along the way. The especially interesting ones we mark on a plastic overlay.
In the science meeting we finally decided on a name for the cruise. After listening to over a dozen ideas, the team settled on the name FLAMINGO which stands for Formation of Lineaments and Anomalous Magmatism In the Northern Galapagos Ocean.
The science meeting
After the meeting, Angela gave a talk on the research she is doing with the Charles Darwin Research Station in the Galapagos. She introduced us to how the El Nino and La Nina weather patterns are having a substantial effect on the biodiversity of the region.
Angela giving her talk
In our off hours...
In our free time, some of the undergrads enjoyed our first dip in the ship's hot tub. Using water that helps to keep the engines cool, the hot tub provides a comfortable spot to catch some sun and enjoy the fresh air. We also enjoy playing cards on deck, playing ring toss, and catching some sun.
Some scientists and crew enjoying the hot tub
Scientists and crew playing Uno
Some crew members playing ring toss
aerial view of the game | <urn:uuid:fe9b0c9b-177f-4b4b-9fc7-260d4fc55bec> | 2.84375 | 486 | Personal Blog | Science & Tech. | 54.278226 |
This data set is part of the WAISCORES project, an NSF-funded project to understand the influence of the West Antarctic ice sheet on climate and sea level change. WAISCORES researchers acquired and analyzed ice cores from the Siple Dome, in the Siple Coast region, West Antarctica. Taylor measured the electrical conductivity (ECM) and Complex Conductivity (CC), a measure of the total ions in the ... ice, in the main Siple Dome ice core. Measurements were taken along the core from a depth of 0 m to 800 m. The project also analyzed shallower cores for ECM and dielectric properties (DEP). (DEP is also a measure of the total ions in the ice, but with lower spatial resolution than the CC.) Albedo measurements where made on the shallow cores and the main core to a depth of 391 m. The data set includes images showing the electrical conductivity of a vertical section of the core. | <urn:uuid:4931ee06-9027-4c5e-9731-48e1a071b188> | 2.84375 | 197 | Structured Data | Science & Tech. | 50.343182 |
Assessing UV-B induced DNA damage in Antarctic plants: is desiccation a compounding factor?Entry ID: ASAC_1310
Abstract: Metadata record for data from ASAC Project 1310
See the link below for public details on this project.
---- Public Summary from Project ----
Increasing UV-radiation over Antarctica each spring may damage DNA in plants. This research determined the susceptibility of Antarctic plants to such damage and investigated the effectiveness of protective and repair mechanisms. This helps predict how plants ... globally will cope with future climate change.
Samples have been collected from Heard Island, and near Casey Station, Antarctica. Three excel fiels constuitute this dataset. Currently, the file detailing samples collected from ASPA 135 near Casey Station (species, weight, water content) is available for download.
Heard Island 2003/4 Samples collected for project 1310
Vascular plant UVB site
GPS coordinates of vascular plant UV site 53 06 57 S, 73 43 30E A total of 4 g of each of 5 species (Pringlea antiscorbutica, Poa cookii. Deschampsia antarctica. Azorella selago, Acaena magellanica) were collected on 5 days over the season. These were analysed for DNA damage, UVB absorbing pigments, and photosynthetic and photoprotective pigments. Chlorophyll fluorescence and leaf temperature were measured on the sampled plants.
GPS co-ordinates: high nutrient site: 53 06 0.419S, 73 43 0.105E 4g of P. antiscorbutica and 0.8g of P. cookii were taken at the high nutrient site, along with chlorophyll fluorescence measurements.
GPS co-ordinates: low nutrient site: 53 06 29.09S, 73 43 00.36E 7.2g of P. antiscorbutica and 3.2g of P. cookii were taken at the low nutrient site, along with chlorophyll fluorescence measurements.
GPS co-ordinates: 53 05 0.645S, 073 40 0.339E
3.2 g of P. antiscorbutica plants was sampled and chlorophyll fluorescence measurements taken.
3.2g of P. antiscorbutica plants was sampled and chlorophyll fluorescence measurements taken.
Ceratodon Paddick Valley
GPS co-ordinates: 53 08 43.44S, 73 40 35.42E 3 g of Ceratodon purpureus was collected.
The fields in this dataset are:
grams dry weight (gdw)
Time (Local Time)
Leaf temperature (1, 2, etc)
F - Chlorophyll Fluorescence
Fm' - Fluorescence maximum measured in the light
Yield - Yield of fluorescence
No. and Mark are stamps put on the data during download
(Click for Interactive Map)
Start Date: 2002-11-09Stop Date: 2003-02-01
Start Date: 2003-12-16Stop Date: 2004-02-26
ISO Topic Category
Quality DNA damage may not happen because there were problems with the UV-B meter logging and so we don't have data to correlate with UV absorbing pigments.
Access Constraints Three datasets are currently included in the file for this project. Only one of these is currently available for download from the URL given below.
Use Constraints This data set conforms to the PICCCBY Attribution License
Data Set Progress
Distribution Media: HTTP
Distribution Size: 68 kb
Distribution Format: excel
Role: TECHNICAL CONTACT
Role: DIF AUTHOR
Phone: +61 2 4221 5753
Fax: +61 2 4221 4135
Email: sharonr at uow.edu.au
Department of Biological Sciences University of Wollongong Northfields Ave
Province or State: New South Wales
Postal Code: 2522
Lovelock C.E., Robinson S.A. (2002), Surface reflectance properties of Antarctic moss and their relationship to plant species, pigment composition and photosynthetic function., Plant, Cell and Environment., 25, 1239-1250
Robinson S.A., Wasley J., Tobin A.K. (2003), Living on the edge - plants and global change in continental and maritime Antarctica., Global Change Biology, 9, 1681-1717
Dunn J.L., Turnbull J.D., Robinson S.A. (2004), Comparison of solvent regimes for the extraction of photosynthetic pigments from leaves of higher plants., Functional Plant Biology, 31, 195-202
Cooper S.M., Dunn J., Russell A.W., Robinson S.A. (2002), Screening pigments: mosses protection against UV-B., ComBio 2002, Sydney. Australia, POS-WED-080
Bargon S., Hemley S., Russell A.W., Robinson S.A. (2002), UV-B induced DNA damage and the effect of light environment on repair of DNA photoproducts in Antarctic mosses., ComBio 2002, Sydney. Australia, POS-WED-081
Robinson S.A., Dunn J. (2003), Antarctic Moss: Survival beneath the ozone layer., 4th conference on Biochemistry, Ecophysiology and Population Biology of Alpine and Polar Plants., Trins, Australia
Robinson S.A., Dunn J. (2003), Antarctic moss: survival beneath the ozone layer., The 4th conference on biochemistry, ecophysiology and population biology of alpine and polar plants., 100, Trins, Australia
Venturini C. (2003), Effects of Light Environment and Temperature on UV-B induced DNA Damage Repair Mechanisms in the Antarctic moss Ceratodon purpureus., Thesis, 1-104, University of Wollongong., Bachelor of Science (Honours) Degree
Leslie S. (2003), The Combined Effects of Desiccation and UV-B Radiation on the Accumulation of DNA Damage, Pigment Composition and Photosynthetic Efficiency in three species of Antarctic moss., Thesis, 1-87, University of Wollongong, Bachelor of Biotechnology (Honours) Degree
Hemley S.J. (2002), UV-B induced DNA damage and the effect of light exposure on repair of DNA photoproducts in an Antarctic moss species (Ceratodon purpureus)., 1-121, University of Wollongong, Bachelor of Biotechnology Degree
Bargon S.D. (2002), UV-B induced DNA photoproducts and the effect of light and temperature on DNA damage repair in an Antarctic moss species (Bryum pseudotriquetrum)., 1-101, University of Wollongong, Bachelor of Science Degree
Cooper S. (2002), A study of UV screening and protective compounds in Antarctic mosses., 1-145, University of Wollongong, Bachelor of Biotechnology Degree
Olsen L.J. (2001), Accumulation of UV-B induced DNA damage in the moss Ceratodon purpureus., 1-125, University of Wollongong, Bachelor of Biotechnology Degree
Robinson S.A., Bargon S., Hemley S. (2003), Repair of DNA photoproducts in Antarctic mosses., Plant Biology 2003, Honolulu, Hawaii
Dunn J., Robinson S.A (2001), Antarctic Moss: survival beneath the ozone layer, the COMBIO2001 conference SYM-05-02
Creation and Review Dates
DIF Creation Date: 2009-06-19
Last DIF Revision Date: 2009-06-23 | <urn:uuid:d3cd3250-27d7-4b01-a766-b657b04f51c3> | 2.75 | 1,637 | Academic Writing | Science & Tech. | 58.994969 |