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- Poster presentation
- Open Access
Evaluating short-read sequence data from the highly redundant, novel transcriptome of Polarella glacialis
© Gibbons et al; licensee BioMed Central Ltd. 2011
Published: 19 September 2011
Dinoflagellates are a diverse group of ecologically important eukaryotic algae, the global impact of which ranges from the large-scale primary production of oxygen to devastating toxic algal blooms . These organisms have exceptionally large genomes (109 to 1011 bases) and highly duplicated genes (which can occur thousands of times within a single genome) . These and other unusual characteristics have made dinoflagellates difficult to study using traditional molecular biology techniques. Sequence data for dinoflagellates are correspondingly sparse, and not a single genome sequence has been published to date.
As part of our project called Assembling the Dinoflagellate Tree of Life (DAToL), our laboratory has sequenced the transcriptome of Polarella glacialis. Its genome is estimated to be only 3 Gb in size, making it one of the smallest known dinoflagellate genomes. Because we had to rely on de novo assemblers that had been tested using data from organisms that are extremely divergent from dinoflagellates, we took special care in our attempts to validate the data. Before expanding our analyses to include additional dinoflagellates, we compared the results from different sequencing and assembly methods.
Total RNA was extracted from cultured P. glacialis. This sample was then divided and shipped to Macrogen for rRNA degradation, library preparation and sequencing. One library was sequenced on one-eighth of a Roche/454 GS FLX picotiter plate using Titanium chemistry. A second library was sequenced using one lane on an Illumina GAIIx sequencer for 78 cycles in both directions (paired end). The sequences were assembled using Newbler, MIRA, Oases and Trinity, and they were analyzed using various custom scripts.
The total amount of unassembled 454 sequence data added to less than one-third of the combined lengths of only those Trinity transcripts that had a significant BLAST hit against a sequence in GenBank, indicating that we did not achieve complete coverage with our 454 data.
Our primary hypothesis was that the longer read lengths of the 454 data might allow the corresponding assemblers to better resolve repetitive sequences, which could be instrumental for assembling conserved regions within highly duplicated genes. Our failure to obtain complete coverage with the 454 dataset undermined our ability to test this hypothesis, although we made several other interesting observations. Notably, despite the vast disparity in the depth of the coverage between the 454 and Illumina assemblies, we observed unique, apparently real sequences within some of the 454 contigs.
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This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. | <urn:uuid:c77ab553-249c-487e-9197-5ed78dbe3acd> | 2.78125 | 912 | Academic Writing | Science & Tech. | 28.27631 | 95,485,881 |
National Center for
2QYG: Crystal Structure Of A Rubisco-Like Protein Rlp2 From Rhodopseudomonas Palustris
Microbiol. Mol. Biol. Rev. (2007) 71 p.576-599
About 30 years have now passed since it was discovered that microbes synthesize RubisCO molecules that differ from the typical plant paradigm. RubisCOs of forms I, II, and III catalyze CO(2) fixation reactions, albeit for potentially different physiological purposes, while the RubisCO-like protein (RLP) (form IV RubisCO) has evolved, thus far at least, to catalyze reactions that are important for sulfur metabolism. RubisCO is the major global CO(2) fixation catalyst, and RLP is a somewhat related protein, exemplified by the fact that some of the latter proteins, along with RubisCO, catalyze similar enolization reactions as a part of their respective catalytic mechanisms. RLP in some organisms catalyzes a key reaction of a methionine salvage pathway, while in green sulfur bacteria, RLP plays a role in oxidative thiosulfate metabolism. In many organisms, the function of RLP is unknown. Indeed, there now appear to be at least six different clades of RLP molecules found in nature. Consideration of the many RubisCO (forms I, II, and III) and RLP (form IV) sequences in the database has subsequently led to a coherent picture of how these proteins may have evolved, with a form III RubisCO arising from the Methanomicrobia as the most likely ultimate source of all RubisCO and RLP lineages. In addition, structure-function analyses of RLP and RubisCO have provided information as to how the active sites of these proteins have evolved for their specific functions. | <urn:uuid:a9fac32e-75dc-4bac-b7f7-e9cb69ca8878> | 2.578125 | 380 | Academic Writing | Science & Tech. | 31.518992 | 95,485,911 |
Sea Breeze and Diurnal Change Over the Tropics
The sea breeze phenomenon is very striking over many parts of the tropics since it is known to produce cooling associated with afternoon showers that occur with regularity on most undisturbed days. Figure 18.1 from a classical diagram of van Bemmelen (1922) illustrates the time evolution of the sea breeze (on shore winds) in Batavia (now Jakarta). The Batavia sea breeze time section shows that it is a shallow circulation essentially confined to the lowest 3 km. The intensity of the upper land breeze is roughly half that of the sea breeze. The land breeze (off shore winds) during the early morning is much less intense by comparison. Extensive observational studies of sea breezes have been conducted by Hsu (1970), Flohn (1965) and many others. Hsu (1970) portrayed a schematic evolution of the land/sea breeze phenomenon based on observations in the Gulf Coast of Texas. Figure 18.2 illustrates this evolution, the diagram being self explanatory. Here the horizontal and vertical extent of the wind system is enclosed within a heavy solid elliptical curve.
KeywordsDiurnal Change Offshore Wind Geostrophic Wind Eastern Tibetan Plateau Land Breeze
- Van Bemmelen, W.: Land-und Seebrise in Batavia. Beitr. Phys. Frei. Atmos. 10, 169–77 (1922)Google Scholar
- Chapman, S., Lindzen, R.S.: Atmospheric Tides. D. Reidel, Dordrecht (1970). 200ppGoogle Scholar
- Lavoie, R.L.: Some aspects of the meteorology of the tropical Pacific viewed from an atoll. Atoll. Res. Bull. No. 96, Honolulu (1963)Google Scholar | <urn:uuid:73703289-ee1e-480b-a670-b3b992290bde> | 3.390625 | 369 | Academic Writing | Science & Tech. | 56.444029 | 95,485,923 |
The Immersion Method
The immersion method permits measurement of refractive index by comparison of the unknown crystal with liquids of known refractive index. A determination of refractive index usually suffices for the identification of isotropic crystals. Refractive index determinations are also fundamental in identification of anisotropic crystals, and the techniques of this chapter are applicable to these as well. Anisotropic crystals, however, have either two or three principal refractive indices, and determination of these requires alignment of principal vibration directions with the polarizer, as well as certain other techniques described in succeeding chapters. Anisotropic crystals also possess other optical and crystallographic characteristics such as optic angle and extinction angle, which are usually needed for identification, and may be determined at the same time as refractive index.
KeywordsRefractive Index Dispersion Curve Color Chip Anisotropic Crystal Dispersion Method
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The Use of Protoplasts in the Study of Coated Vesicles
In plant cells the plasma membrane functions as a selectively permeable boundary around the cytoplasm, acting in concert with the cell wall as an interface with the external environment. Organelles associated with the inner surface of the plasma membrane of walled cells include endoplasmic reticulum associated with the plasmodesmata, cytoskeletal elements such as cortical microtubules and microfilaments, and smooth and coated vesicles. As disruption of the plasmodesmata due to enzymatic degradation of the cell wall during the production of protoplasts also disrupts the association of the endoplasmic reticulum with the plasma membrane, in protoplasts the organelles associated with the plasma membrane are primarily cytoskeletal elements and smooth and coated vesicles of the cortical cytoplasm.
KeywordsCortical Microtubule Coated Vesicle Plant Protoplast Cortical Cytoplasm Clathrin Coat
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- Fowke LC, Griffing LR, Mersey BG, van der Valk P (1983a) Protoplasts for studies of the plasma membrane and associated cell organelles. Protoplasts 1983, Lecture Proc 6th Int Protoplast Symp Basel. Exper Suppl (Basel) 46:101–110Google Scholar
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Rhombus is inscribed in rectangle so that vertices , , , and are interior points on sides , , , and , respectively. It is given that , , , and . Let , in lowest terms, denote the perimeter of . Find .
This problem is copyrighted by the American Mathematics Competitions.
Instructions for entering answers:
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04 October 2002
04 October 2002
Nanotubes, stringy supermolecules already used to create fuel cell batteries and tiny computer circuits, could find myriad new applications ranging from disease treatment to plastics manufacturing to information storage, reports a Purdue University research team.
Scientists led by Purdue chemist Hicham Fenniri have learned to create multiple species of nanotubes that possess unprecedented physical and chemical properties, each of which could lead to a different industrial application. Also unprecedented is the compete control they have over the nanotubes' formation, which allows the team to virtually ""dial up"" the properties they wish their nanotubes to possess. The findings could greatly expand the materials available for use on the nanoscale.
""Instead of being limited to building blocks of one size, shape and color, it's as though we now have a brickyard with many different varieties,"" Fenniri said. ""This research could give a nanotechnologist a lot more materials for construction.""
The research appeared on the Journal of the American Chemical Society's Web site. A print publication date has not yet been determined.
Since their discovery in 1991, nanotubes have become one of the most promising building blocks for nanotechnology. Last year, Japan's NEC Corp. developed a nanotube-based fuel cell battery that could power a notebook computer for days rather than hours. At about the same time, IBM researchers found a way to create logic circuits from individual carbon nanotubes, which could make them an alternative to silicon in future computers. After several years of pursuing their own research, Fenniri's group has discovered a new class of nanotubes that could dramatically expand their uses in industry.
Rather than work with carbon or metals, as other groups have done, the Fenniri team has formed nanotubes out of synthetic organic molecules. While other materials have distinct advantages, they are not as easily managed as the materials the Fenniri team is working with.
""By using synthetic chemistry, we have gained complete control over the formation of our nanotubes,"" Fenniri said. ""More control in the lab should give more options to industry.""
One way the new nanotubes can be customized is by using them as scaffolding for other materials. Fenniri's nanotube looks like a spiral-shaped stack of rings; each ring is made of six molecules shaped roughly like pie wedges. On the outside of the spiral, the team has learned to attach other molecules, which hang off the tubes like charms on a charm bracelet. The attached molecules then lend their properties to the outside of the nanotube.
For example, if the component molecules of nylon are attached, the nanotubes can then be turned into very long and flexible fibers that are, nonetheless, very strong.
""They could be made into an improved version of nylon,"" Fenniri said. ""And nylon has a lot more uses than making your socks stretch. We could use these fibers to reinforce everything from boat hulls and aircraft to body armor and parachutes.""
Another secret to creating custom-made tubes lies in manipulating a property called chirality, which has to do with the direction the spiral-shaped tubes twist. Nature only twists molecules in one direction - this is why DNA molecules always twist to the right, and are described as having right-handed chirality. But Fenniri's team can make tubes that twist in either direction, creating left-handed nanotubes with abilities that their right-handed cousins often do not have.
""We can create two nanotubes that are made of the same materials, but that behave differently,"" Fenniri said. ""Just like a flipped-over puzzle piece doesn't fit in its hole, a left-handed nanotube can react with different substances than its corresponding right-handed tube.""
While experimenting with controlling their nanotubes' properties, the Fenniri team discovered some unexpected behaviors their nanotubes exhibit.
""We have found that the nanotubes promote their own formation,"" Fenniri said. ""Such behavior is very reminiscent of living systems, in that they replicate and adapt to their environment.""
Realizing that their homegrown nanotubes catalyze their own formation opened a whole new field of research for the team. They found that by placing the raw materials from which nanotubes form into a test tube, then adjusting such conditions as temperature and pressure, the nanotubes could organize themselves into one of many different configurations, several never seen previously.
""You could imagine that one type of nanotube forms at 25 degrees Celsius, but another type with very different physical and chemical properties would form at 70 degrees,"" Fenniri said. ""That's a simplification, of course, but it illustrates the principles we have uncovered.""
The relative ease of manipulating the properties of nanotubes makes Fenniri optimistic that many new applications will be possible. One possibility is to use the nanotubes in disease treatment.
""Many drugs destroy infectious bacteria by poking holes in their cellular membranes and leaking out their nutrients, just like pricking a hole in a balloon,"" he said. ""Our nanotubes could also act in this manner, but in addition, they have the ability to lure the bacteria with a bait that guides them to the cell membrane where they can start destroying the cell.""
Further exploitation of the tubes' dial-up properties could lead to nanotubes that conduct electricity or photons, making them useful in computer memory systems, high-definition displays, biosensors and drug delivery systems. Fenniri is hopeful the findings will prove beneficial in many fields.
""Nanotechnology relies on our ability to control the behavior of matter at the molecular scale,"" he said. ""The versatility and robustness of our system is already pointing the way towards numerous applications in a fairly broad range of disciplines. It should help nanotubes on their way to becoming the nanoworld's jack-of-all-trades.""
Funding for this research is provided by grants from the National Science Foundation and the American Chemical Society, awards from 3M and the Research Corp., and by Purdue University.
Applications for composites in the sports and leisure sector will be showcased by various exhibitors at Composites Europe in Stuttgart, Germany, on 6-8 November.
The programme has been announced for the second Composites in Sport Conference and Exhibition, being held at Loughborough University, UK, on 3-4 October 2018. | <urn:uuid:06eefd76-5021-47f7-be39-3c42204aa0c2> | 3.96875 | 1,342 | News Article | Science & Tech. | 29.850579 | 95,485,965 |
Scientists in Germany have found that a significant route of transmission of Salmonella in non egg-laying snakes is from the mother to the offspring during pregnancy and birth.
One source of human Salmonella infection is associated with pet reptiles and these cases are often serious – sometimes causing septicaemia, meningitis or even death, especially among children and those at risk due to a compromised immune system.
A high percentage of snakes carry the food-poisoning bug Salmonella, but until this study we didn’t know whether the snakes became infected through eating contaminated food, or by another route.
Lucy Mansfield | alfa
World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt
Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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Fukushima's Spreading Impact
Japan’s spiraling reactor accident threatens nuclear power’s future.
The nuclear accident at Japan’s troubled Fukushima Daiichi reactor complex appears to be heading from very bad to critical in the wake of the third explosion in four days, a fire in one of the plant’s spent fuel ponds, and radiation readings spiking to deadly levels within the plant.
Authorities in Tokyo, 140 miles southwest of the plant, observed rising radiation levels yesterday, and anecdotal reports of residents leaving Tokyo are mounting. Meanwhile, iodine pills to ward off nuclear poisoning are selling out in some cities on the West Coast of the United States and Canada, despite assurances from nuclear safety authorities that the risk of harmful exposures in North America is minimal.
Whatever the immediate dangers to health, one clear victim is the growing confidence in nuclear energy internationally. German Chancellor Angela Merkel’s announcement today was the most decisive turnabout in response to the crisis—she suspended her government’s decision just last year to extend the operating life of Germany’s nuclear power plants. She also ordered the immediate shutdown of seven plants built before 1980; officials say the plants will remain closed for safety evaluations through at least June.
Similarly doomed could be Italian utility Enel’s plans to revive nuclear energy. Enel and France’s Electricité de France have proposed the construction of four reactors that could provide a quarter of Italy’s electricity, but they must first win a referendum that would overturn Italy’s post-Chernobyl nuclear moratorium. The vote is set for this spring.
Japan Earthquake Coverage:
- Newer Nuclear Reactors May Not Have Failed in Japan
- Questions Over the Design of Fukushima Nuclear Plant
- Internet Activists Mobilize for Japan
- 80 Seconds of Warning for Tokyo
- How Japan's Earthquake and Tsunami Warning Systems Work
- Crisis Continues at Japanese Nuclear Plants
- Cellular Technology That Told Japan An Earthquake Was Coming
- The Reliability of Tsunami Detection Buoys
In an interview with Bloomberg News, the Indian Nuclear Power Corporation’s chairman acknowledged that Japan’s crisis could be “a big dampener” for his country’s plans to invest in nuclear generation by 2030. China, however, was holding firm on its nuclear ambitions. The Chinese government issued a statement Monday affirming its massive shift toward nuclear power—with over a dozen reactors in construction.
The unfolding tragedy’s impact on a nascent revival of reactor construction in the United States is too early to call, say experts. “It will be at least the end of the week before we will know enough about the progression of these accidents to assess policy outcomes,” says Per Peterson, a professor of nuclear engineering at the University of California, Berkeley. “Much will depend upon whether any radiation deaths or significant land contamination result.”
So far, the Obama administration is standing by hopes for a nuclear renaissance. Daniel Poneman, the U.S. deputy secretary of energy, said at a White House news conference Monday that nuclear has a key role in the U.S. power mix: “We have 104 operating reactors—that’s 20 percent of the electricity of this country; 70 percent of the carbon-free electricity in this country comes from nuclear power. We view nuclear energy as a very important component to the overall portfolio we’re trying to build for a clean energy future.”
However, some in Congress are pushing for a rethink. Connecticut Sen. Joe Lieberman, chair of the Homeland Security and Governmental Affairs Committee and a longtime nuclear supporter, told CBS News this weekend that the U.S. should “quickly put the brakes” on reactor construction until the Japanese incidents are analyzed.
The U.S. Nuclear Regulatory Commission (NRC) is expected to vote this year on the first of two construction permits; the most advanced is Southern Company’s proposal to build two new reactors at its Vogtle, Georgia, nuclear power plant. Southern has conditional approval for an $8.3-billion federal loan guarantee to backstop its financing and has broken ground at the site.
Meanwhile, Rep. Edward Markey (D-Massachusetts) has been critical of the NRC’s decision-making on the Westinghouse AP1000—the reactor design for half of the 28 reactors proposed in the U.S., including Southern’s. Markey sent a letter to the NRC last week criticizing its plan to approve the AP1000 this spring or summer despite a dissenting opinion from one of its senior engineers, who has raised doubts about the earthquake hardiness of the AP1000’s concrete-steel hybrid containment building.
The earthquake concerns, ironically, undermine confidence in the passive safety system designed to make the AP1000 less vulnerable to the power blackout that sparked the Japanese crisis. The AP1000 holds a pool of water above the reactor, ready to flood it via gravity. But Markey’s letter suggests that if the AP1000’s containment building is compromised by an earthquake, the passive cooling system could fail.
Southern Company released a statement yesterday saying that its leadership “continues to monitor the recent events in Japan, and remains committed to completing the new Vogtle units on schedule and on budget.” The statement argues that the site’s seismic risk is “much lower” than Japan’s, as is the risk of a tsunami 130 miles from the Atlantic coast and 220 feet above sea level.
The French nuclear engineering firm Areva also defended its EPR design, which is also pending NRC approval. While the EPR relies on active pumping to maintain reactor cooling, an Areva spokesman told Technology Review yesterday that it has extra backup generators for added redundancy. And the diesel tanks to fuel the EPR’s generators would be protected by bunkers, unlike those that were washed away by Friday’s tsunami in Japan.
David Lochbaum, a nuclear engineer and director for nuclear safety at the Union of Concerned Scientists, is critical of the NRC’s policing of safety at existing plants in the U.S. He wants the NRC to take a second look at critical vulnerabilities to power blackouts, including outdated fire-suppression equipment and battery-power backups that, at most U.S. plants, provide for only four hours of reactor cooling—half the capacity of batteries at Japanese plants. “We’re light compared to what Japan had, and Japan came up short,” says Lochbaum.
Just as serious is the U.S. nuclear operators’ heavy reliance on cooling ponds rather than more expensive but safer dry-cask storage of their spent fuel. Lochbaum notes that the spent fuel ponds for 23 U.S. reactors are in the attic of their concrete reactor buildings—structures that were blown away by the first two hydrogen explosions at Fukushima.
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Formalizing Style to Understand Descriptions of Software Architecture
Gregory Abowd, Robert Allen, and David Garlan
ACM Transactions on Software Engineering and Methodology 4(4):319-364, October 1995.
|The software architecture of most systems is usually described informally and diagrammatically by means of boxes and lines. In order for these descriptions to be meaningful, the diagrams are understood by interpreting the boxes and lines in specic, conventionalized ways. The informal, imprecise nature of these interpretations has a number of limitations. In this paper we consider these conventionalized interpretations as architectural styles and provide a formal framework for their uniform denition. In addition to providing a template for precisely dening new architectural styles, this framework allows for analysis within and between dierent architectural styles.|
|software architecture, software design, architectural style, architectural description, architectural analysis, formal specification, the Z notation|
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Distribution of137Cs and228Ra in the sediments of Aswan High Dam lake
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Sediment samples of the High Dam lake were investigated for their137Cs,226Ra,228Th, and40K content, using low-level γ-spectroscopy. The results show that at the begining of the lake (500 km from the High Dam), where sediments consist mostly of sand, the level of137Cs is very low (0.1 Bq kg−1). The maximum value (22.3 Bq kg−1) was found 40 km from the wall of the High Dam, where the composition of the sediments is nearly 50% clays. The distribution of the natural nuclides226Ra,228Th, and40K shows a different trend.
KeywordsClay Physical Chemistry Inorganic Chemistry Sediment Sample
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Arctic methane emissions
Arctic methane release is the release of methane from seas and soils in permafrost regions of the Arctic. While a long-term natural process, it is exacerbated by global warming. This results in a positive feedback effect, as methane is itself a powerful greenhouse gas.
The Arctic region is one of the many natural sources of the greenhouse gas methane. Global warming accelerates its release, due to both release of methane from existing stores, and from methanogenesis in rotting biomass. Large quantities of methane are stored in the Arctic in natural gas deposits, permafrost, and as undersea clathrates. Permafrost and clathrates degrade on warming, thus large releases of methane from these sources may arise as a result of global warming. Other sources of methane include submarine taliks, river transport, ice complex retreat, submarine permafrost and decaying gas hydrate deposits.
Concentrations in the Arctic atmosphere are higher by 8–10% than that in the Antarctic atmosphere. During cold glacier epochs, this gradient decreases to practically insignificant levels. Land ecosystems are considered the main sources of this asymmetry, although it has been suggested that "the role of the Arctic Ocean is significantly underestimated." Soil temperature and moisture levels have been found to be significant variables in soil methane fluxes in tundra environments.
Contribution to climate change
The release of methane from the Arctic is in itself a major contributor to global warming as a result of polar amplification. Recent observations in the Siberian arctic show increased rates of methane release from the Arctic seabed. Land-based permafrost, also in the Siberian arctic, was estimated in 2013 to release 17 million tonnes of methane per year – a significant increase on the 3.8 million tons estimated in 2006, and estimates before then of just 0.5 million tonnes. This compares to around 500 million tonnes released into the atmosphere annually from all sources.
Shakhova et al. (2008) estimate that not less than 1,400 gigatonnes (Gt) of carbon is presently locked up as methane and methane hydrates under the Arctic submarine permafrost, and 5–10% of that area is subject to puncturing by open taliks. They conclude that "release of up to 50 Gt of predicted amount of hydrate storage [is] highly possible for abrupt release at any time". That would increase the methane content of the planet's atmosphere by a factor of twelve.
In 2008 the United States Department of Energy National Laboratory system identified potential clathrate destabilization in the Arctic as one of the most serious scenarios for abrupt climate change, which have been singled out for priority research. The US Climate Change Science Program released a report in late December 2008 estimating the gravity of the risk of clathrate destabilization, alongside three other credible abrupt climate change scenarios.
Study findings based on NASA's CARVE mission concluded in 2015, that methane emissions in the Arctic during the cold season are higher than previously thought. The press release by JPL explained:
The water trapped in the soil doesn't freeze completely even below 32 degrees Fahrenheit (0 degrees Celsius). The top layer of the ground, known as the active layer, thaws in the summer and refreezes in the winter, and it experiences a kind of sandwiching effect as it freezes. When temperatures are right around 32 degrees Fahrenheit – the so-called "zero curtain" – the top and bottom of the active layer begin to freeze, while the middle remains insulated. Microorganisms in this unfrozen middle layer continue to break down organic matter and emit methane many months into the Arctic's cold period each year.
Hong et al. (2017) studied the seepage from large mounds of hydrates in the shallow arctic seas at Storfjordrenna, in the Barents Sea close to Svalbard. They showed that though the temperature of the sea bed has fluctuated seasonally over the last century, between 1.8 and 4.8 °C, it has only affected release of methane to a depth of about 1.6 meters. Hydrates can be stable through the top 60 meters of the sediments and the current rapid releases came from deeper below the sea floor. They concluded that the increase in flux started hundreds to thousands of years ago well before the onset of warming that others speculated as its cause, and that these seepages are not increasing due to momentary warming. Summarizing his research, Hong stated:
"The results of our study indicate that the immense seeping found in this area is a result of natural state of the system. Understanding how methane interacts with other important geological, chemical and biological processes in the Earth system is essential and should be the emphasis of our scientific community,"
Further research by Klaus Wallmann et al. (2018) found that the hydrate release is due to the rebound of the sea bed after the ice melted. The methane dissociation began around 8,000 years ago when the land began to rise faster than the sea level, and the water as a result sarted to get shallower with less hydrostatic pressure. This dissociation therefore was a result of the uplift of the sea bed rather than anthropogenic warming. The amount of methane released by the hydrate dissociation was small. They found that the methane seeps originate not from the hydrates but from deep geological gas reservoirs (seepage from these formed the hydrates originally). They concluded that the hydrates acted as a dynamic seal regulating the methane emissions from the deep geological gas reservoirs and when they were dissociated 8,000 years ago, weakening the seal, this led to the higher methane release still observed today.
Arctic sea ice
A 2015 study concluded that Arctic sea ice decline accelerates methane emissions from the Arctic tundra. One of the study researchers noted, "The expectation is that with further sea ice decline, temperatures in the Arctic will continue to rise, and so will methane emissions from northern wetlands."
A 2014 study found evidence for methane cycling below the ice sheet of the Russell Glacier, based on subglacial drainage samples which were dominated by Proteobacteria. During the study, the most widespread surface melt on record for the past 120 years was observed in Greenland; on 12 July 2012, unfrozen water was present on almost the entire ice sheet surface (98.6%). The findings indicate that methanotrophs could serve as a biological methane sink in the subglacial ecosystem, and the region was, at least during the sample time, a source of atmospheric methane. Scaled dissolved methane flux during the 4 months of the summer melt season was estimated at 990 Mg CH4. Because the Russell-Leverett Glacier is representative of similar Greenland outlet glaciers, the researchers concluded that the Greenland Ice Sheet may represent a significant global methane source. A study in 2016 concluded that methane clathrates may exist below Greenland's and Antarctica's ice sheets, based on past evidence.
Loss of permafrost
Sea ice loss is correlated with warming of Northern latitudes. This has melting effects on permafrost, both in the sea, and on land. Lawrence et al. suggest that current rapid melting of the sea ice may induce a rapid melting of arctic permafrost. This has consequential effects on methane release, and wildlife. Some studies imply a direct link, as they predict cold air passing over ice is replaced by warm air passing over the sea. This warm air carries heat to the permafrost around the Arctic, and melts it. This permafrost then releases huge quantities of methane. Methane release can be gaseous, but is also transported in solution by rivers. New Scientist states that "Since existing models do not include feedback effects such as the heat generated by decomposition, the permafrost could melt far faster than generally thought."
There is another possible mechanism for rapid methane release. As the Arctic Ocean becomes more and more ice free, the ocean absorbs more of the incident energy from the sun. The Arctic Ocean becomes warmer than the former ice cover and much more water vapour enters the air. At times when the adjacent land is colder than the sea, this causes rising air above the sea and an off-shore wind as air over the land comes in to replace the rising air over the sea. As the air rises, the dew point is reached and clouds form, releasing latent heat and further reinforcing the buoyancy of the air over the ocean. All this results in air being drawn from the south across the tundra rather than the present situation of cold air flowing toward the south from the cold sinking air over the Arctic Ocean. The extra heat being drawn from the south further accelerates the warming of the permafrost and the Arctic Ocean with increased release of methane.
Sinkholes discovered in the Yamal Peninsula in Siberia, Russia beginning in July 2014 are believed by Russian researchers to have been caused by methane released due to permafrost thawing. Near the bottom of the first sinkhole, air contained unusually high concentrations of methane, according to tests conducted by the researchers. This hypothesis points to the destabilization of gas hydrates containing huge amounts of methane gas.
According to researchers at Norway's Centre for Arctic Gas Hydrate (CAGE), through a process called geothermal heat flux, the Siberian permafrost which extends to the seabed of the Kara Sea, a section of the Arctic Ocean between the Yamal Peninsula and Novaya Zemlya, is thawing. According to a CAGE researcher, Aleksei Portnov,
"The thawing of permafrost on the ocean floor is an ongoing process, likely to be exaggerated by the global warming of the world´s oceans."— CAGE 2014
Methane hydrate is leaking in an area of at least 7500 m2. In some areas gas flares extend up to 25 m (82 ft). Prior to their research it was proposed that methane was tightly sealed into the permafrost by water depths up to 100 m (330 ft). Close to the shore however, where the permafrost seal tapers to as little as 20 m (66 ft), there are significant amounts of gas leakage.
Sea ice, and the cold conditions it sustains, serves to stabilise methane deposits on and near the shoreline, preventing the clathrate breaking down and outgassing methane into the atmosphere, causing further warming. Melting of this ice may release large quantities of methane, a powerful greenhouse gas into the atmosphere, causing further warming in a strong positive feedback cycle.
Even with existing levels of warming and melting of the Arctic region, submarine methane releases linked to clathrate breakdown have been discovered, and demonstrated to be leaking into the atmosphere. A 2011 Russian survey off the East Siberian coast found plumes wider than one kilometer releasing methane directly into the atmosphere.
According to monitoring carried out in 2003/2004 by Shakhova et al., the surface layer of shelf water in the East Siberian Sea and Laptev Sea was supersaturated up to 2500% relative to then present average atmospheric methane content of 1.85 ppm. Anomalously high concentrations (up to 154 nM or 4400% supersaturation) of dissolved methane in the bottom layer of shelf water suggest that the bottom layer is somehow affected by near-bottom sources. Considering the possible formation mechanisms of such plumes, their studies indicated thermoabrasion and the effects of shallow gas or gas hydrates release.
The climatic effects of a potential release of methane from global ocean clathrates may be significant on timescales of 1–100 thousand years, depending on the water temperature.
- Arctic dipole anomaly
- Atmospheric methane
- Clathrate gun hypothesis
- Clathrate hydrate
- Methane chimney
- Methane clathrate
- Long-term effects of global warming
- Permafrost Carbon Cycle
- Soil respiration
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- Methane hydrates and global warming, RealClimate from December 12, 2005
- Arctic Methane Emergency Group UK Based 'Arctic Methane Emergency Group' calling for action on Arctic methane crisis
- Last Hours Film Short film about potential for massive release of arctic methane
- Methane Tracker Online tools to visualize atmospheric methane releases
- Film Arctic Methane: Why The Sea Ice Matters Featuring James Hansen, Peter Wadhams, and Natalia Shakhova
- Exclusive new pictures INSIDE Siberian crater Siberian Times, 2014
- 7,000 underground gas bubbles poised to 'explode' in Arctic Siberian Times, 2017
- Climate Change in the Arctic and Model Projections (Video) | <urn:uuid:02b6b49a-0c01-4d4d-ba86-c51ffec4d040> | 4.125 | 4,934 | Knowledge Article | Science & Tech. | 58.4837 | 95,486,006 |
This paper describes mainly the 1997 version of the Solar EUV Rocket Telescope and Spectrograph (SERTS-97), a scientific experiment that operated on NASA's suborbital rocket flight 36.167-GS. Its function was to study activity on the Sun and to provide a cross calibration for the CDS instrument on the SOHO satellite. The experiment was designed, built, and tested by the Solar Physics Branch of the Laboratory for Astronomy and Solar Physics at the Goddard Space Flight Center (GSFC). Other essential sections of the rocket were built under the management of the Sounding Rockets Program Office. These sections include the electronics, timers, IGN despin, the SPARCS pointing controls, the S-19 flight course correction section, the rocket motors, the telemetry, ORSA, and OGIVE. | <urn:uuid:768a019a-58af-4acd-a497-77ecb9ef0d2c> | 2.96875 | 165 | Knowledge Article | Science & Tech. | 40.853967 | 95,486,046 |
Meaning of specific heat
— Physics. Physics.
- the number of calories required to raise the temperature of 1 gram of a substance 1°C, or the number of BTU's per pound per degree F.
- (originally) the ratio of the thermal capacity of a substance to that of standard material. | <urn:uuid:d59b2f41-ee0a-4e68-8985-65abc2869322> | 3.015625 | 66 | Structured Data | Science & Tech. | 61.458393 | 95,486,053 |
Researchers at the University of Warwick are examining naturally occurring fungi that kill the varroa mite. They are also exploring a range of ways to deliver the killer fungus throughout the hives from bee fungal foot baths to powder sprays.
It well known that bees world wide are suffering serious declines and one of the causes of that decline is the varroa mite, Varroa destructor. Varroa mites feed on the circulatory fluid of honey bee pupae and adult bees, and in so doing they activate and transmit diseases which reduce the life expectancy of the bees and cause the colony to decline.
Varroa has had a major impact in all countries where it has become established, for example it has caused losses of 30–50% of honey bee colonies when it first arrived in the UK and is now endemic. The loss of honey bees on this scale is affecting the pollination of commercial crops and wild plants. It originates in Asia, but has extended its range world-wide.
At present, the management of varroa is based on the use of chemical pesticides, but the mites are developing resistance. Biological control technologies (the use of one organism to control another) could offer a way of moving pest management strategies away from a reliance on these synthetic pesticides but no natural insect or other enemies of varroa species have been identified on the varroa or on their bee hosts.
Now Defra-funded studies by researchers at the University of Warwick’s plant research group Warwick HRI, and Rothamsted Research has found some new natural enemies of varroa from other hosts.
University of Warwick researcher Dr Dave Chandler said:
"We examined 50 different types of fungi that afflict other insects (known as entomopathogenic fungi) to see if they would kill varroa. We needed to find fungi that were effective killers of varroa, had a low impact on the bees, and worked in the warm and dry conditions typically found in bee hives. Of the original 50 fungi we are now focusing on four that best match those three requirements."
The team now hope to secure additional funding to further examine the effectiveness of these four fungi and to begin to consider the best ways of applying this weapon across the hive. A number of approaches are being considered including having fungal footbaths at the main entrances to hives. However the complex environment within bee hives means that more devious means of application may be needed.
Dr Chandler will be hosting the Society for Invertebrate Pathology international conference at the University of Warwick, starting 4th August, where a special session is being held on honey bee health. The session will bring together some the world’s leading experts in bee colony collapse disorder to discuss the full range of its possible underlying causes.
Richard Fern | alfa
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In a paper published Dec. 14 in PLoS ONE, MSU researchers Denver W. Fowler, Elizabeth A. Freedman, John B. Scannella and Robert E. Kambic (now at Brown University in Rhode Island), describe how comparing modern birds of prey helped develop a new behavior model for sickle-clawed carnivorous dinosaurs like Velociraptor.
"This study is a real game-changer," said lead author Fowler. "It completely overhauls our perception of these little predatory dinosaurs, changing the way we think about their ecology and evolution."
The study focuses on dromaeosaurids; a group of small predatory dinosaurs that include the famous Velociraptor and its larger relative, Deinonychus. Dromaeosaurids are closely related to birds, and are most famous for possessing an enlarged sickle-claw on digit two (inside toe) of the foot. Previous researchers suggested that this claw was used to slash at prey, or help climb up their hides, but the new study proposes a different behavior.
"Modern hawks and eagles possess a similar enlarged claw on their digit 2's, something that hadn't been noted before we published on it back in 2009," Fowler said. "We showed that the enlarged D-2 claws are used as anchors, latching into the prey, preventing their escape. We interpret the sickle claw of dromaeosaurids as having evolved to do the same thing: latching in, and holding on."
As in modern birds of prey, precise use of the claw is related to relative prey size.
"This strategy is only really needed for prey that are about the same size as the predator; large enough that they might struggle and escape from the feet," Fowler said. "Smaller prey are just squeezed to death, but with large prey all the predator can do is hold on and stop it from escaping, then basically just eat it alive. Dromaeosaurs lack any obvious adaptations for dispatching their victims, so just like hawks and eagles, they probably ate their prey alive too."
Other features of bird of prey feet gave clues as to the functional anatomy of their ancient relatives; toe proportions of dromaeosaurids seemed more suited for grasping than running, and the metatarsus (bones between the ankles and the toes) is more adapted for strength than speed.
"Unlike humans, most dinosaurs and birds only walk on their toes, so the metatarsus forms part of the leg itself," Fowler said. "A long metatarsus lets you take bigger strides to run faster; but in dromaeosaurids, the metatarsus is very short, which is odd."
Fowler thinks that this indicates that Velociraptor and its kin were adapted for a strategy other than simply running after prey.
"When we look at modern birds of prey, a relatively short metatarsus is one feature that gives the bird additional strength in its feet," Fowler continued. "Velociraptor and Deinonychus also have a very short, stout metatarsus, suggesting that they had great strength but wouldn't have been very fast runners."
The ecological implications become especially interesting when dromaeosaurids are contrasted with their closest relatives: a very similar group of small carnivorous dinosaurs called troodontids, Fowler said.
"Troodontids and dromaeosaurids started out looking very similar, but over about 60 million years they evolved in opposite directions, adapting to different niches," Fowler said. "Dromaeosaurids evolved towards stronger, slower feet; suggesting a stealthy ambush predatory strategy, adapted for relatively large prey. By contrast, troodontids evolved a longer metatarsus for speed and a more precise, but weaker grip, suggesting they were swift but probably took relatively smaller prey."
The study also has implications for the next closest relatives of troodontids and dromaeosaurids: birds. An important step in the origin of modern birds was the evolution of the perching foot.
"A grasping foot is present in the closest relatives of birds, but also in the earliest birds like Archaeopteryx," Fowler said. "We suggest that this originally evolved for predation, but would also have been available for use in perching. This is what we call 'exaptation:' a structure evolved originally for one purpose that can later be appropriated for a different use."
The new study proposes that a similar mechanism may be responsible for the evolution of flight.
"When a modern hawk has latched its enlarged claws into its prey, it can no longer use the feet for stabilization and positioning," Fowler said. "Instead the predator flaps its wings so that the prey stays underneath its feet, where it can be pinned down by the predator's bodyweight."
The researchers suggest that this 'stability flapping' uses less energy than flight, making it an intermediate flapping behavior that may be key to understanding how flight evolved.
"The predator's flapping just maintains its position, and does not need to be as powerful or vigorous as full flight would require. Get on top, stay on top; it's not trying to fly away," Fowler said. "We see fully formed wings in exquisitely preserved dromaeosaurid fossils, and from biomechanical studies we can show that they were also able to perform a rudimentary flapping stroke. Most researchers think that they weren't powerful enough to fly; we propose that the less demanding stability flapping would be a viable use for such a wing, and this behavior would be consistent with the unusual adaptations of the feet."
Another group of researchers has proposed that understanding flapping behaviors is key to understanding the evolution of flight, a view with which Fowler agrees.
"If we look at modern birds, we see flapping being used for all sorts of behaviors outside of flight. In our paper, we are formally proposing the 'flapping first' model: where flapping evolved for other behaviors first, and was only later exapted for flight by birds."
The researchers believe their new ideas will open multiple new lines of investigation into dinosaur paleobiology, and the evolution of novel anatomical structures.
"As with other research conducted at the Jack Horner paleo lab, we're looking at old paleontological questions with a fresh perspective, taking a different angle," Fowler said. "Just as you have to get beyond the idea that feet are used just for walking, so we are coming to realize that many unusual structures in modern animals originally evolved for quite different purposes. Revealing the selection pathways that mold and produce these structures helps us to better understand the major evolutionary transitions that shaped life on this planet."
To learn more about the latest research in Horner's paleo lab, go to http://www.facebook.com/pages/Horner-Paleo-Lab-Museum-of-the-Rockies/230141317002543
Evelyn Boswell | EurekAlert!
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For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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The simple method promises to be as significant a technique for dating ceramic materials as radiocarbon dating has become for organic materials such as bone or wood.
A team from The University of Manchester and The University of Edinburgh has discovered a new technique which they call 'rehydroxylation dating' that can be used on fired clay ceramics like bricks, tile and pottery.
Working with The Museum of London, the team has been able to date brick samples from Roman, medieval and modern periods with remarkable accuracy.
They have established that their technique can be used to determine the age of objects up to 2,000 years old – but believe it has the potential to be used to date objects around 10,000 years old.
The exciting new findings have been published online today (20 May 2009) by the Proceedings of the Royal Society A.
The method relies on the fact that fired clay ceramic material will start to chemically react with atmospheric moisture as soon as it is removed from the kiln after firing. This continues over its lifetime causing it to increase in weight – the older the material, the greater the weight gain.
In 2003 the Manchester and Edinburgh team discovered a new law that precisely defines how the rate of reaction between ceramic and water varies over time.
The application of this law underpins the new dating method because the amount of water that is chemically combined with a ceramic provides an 'internal clock' that can be accessed to determine its age.
The technique involves measuring the mass of a sample of ceramic and then heating it to around 500 degrees Celsius in a furnace, which removes the water.
The sample is then monitored in a super-accurate measuring device known as a microbalance, to determine the precise rate at which the ceramic will combine with water over time.
Using the time law, it is possible to extrapolate the information collected to calculate the time it will take to regain the mass lost on heating – revealing the sample's age.
Lead author Dr Moira Wilson, Senior Lecturer in the School of Mechanical, Aerospace and Civil Engineering (MACE), said: "These findings come after many years of hard work. We are extremely excited by the potential of this new technique, which could become an established way of determining the age of ceramic artefacts of archaeological interest.
"The method could also be turned on its head and used to establish the mean temperature of a material over its lifetime, if a precise date of firing were known. This could potentially be useful in climate change studies.
"As well as the new dating method, there are also more wide-ranging applications of the work, such as the detection of forged ceramic."
The three-year £100,000 project was funded by the Leverhulme Trust, with the microbalance - which measures mass to 1/10th of a millionth of a gram – funded by a £66,000 grant from the Engineering and Physical Science Research Council (EPSRC).
Researchers are now planning to look at whether the new dating technique can be applied to earthenware, bone china and porcelain.
The paper, entitled 'Dating fired-clay ceramics using long-term power-law rehydroxylation kinetics' has been published online and is due to appear in a future edition of Proceedings of the Royal Society A. A copy of the paper is available on request.
The full research team comprised Dr Moira Wilson, Dr Margaret Carter, Prof William Hoff, Ceren Ince, Shaun Savage and Bernard McKay from The University of Manchester, Professor Chris Hall from the School of Engineering and Centre for Materials Science and Engineering at The University of Edinburgh and Ian Betts from The Museum of London.
The Canterbury Archaeological Trust provided additional samples and information for the study while Ibstock Brick Ltd provided kiln-fresh bricks.
Alex Waddington | EurekAlert!
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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Thursday, January 13, 2011
Ice Circles on the North Branch
Meetings at the North Branch Nature Center frequently get interrupted by natural phenomena. Usually it’s a bird sighting or a butterfly, certainly something alive. But what had us pulling on boots and hats recently was something more geometrical in nature. Larry Clarfeld, environmental educator at NBNC, had found what’s called an ice circle/disc or “pizza ice”. When he first came upon the ice circle along a bend of the North Branch of the Winooski River, it was slowly revolving in place. This particular stretch of river has a sharp bend near a spot we call “otter rock”. The river here features a deep hole and an eddy that may have helped the circle to form.
Expert on ice formation, Faye Hicks, a professor at the department of civil and environmental engineering at the University of Alberta in Edmonton, says these rarely-seen discs form near the outside of a bend in the river. When flow enters a river bend, flow velocities increase due to the effects of centrifugal acceleration; also, the bulk of the flow is pushed towards the outer bank."
"This high-velocity flow curves around the outer bank of the bend and, if there is an ice cover in the bend, the curving flow creates a curved drag force on the underside of the ice," Hicks said.
The rotating ice scrapes along the bank or nearby ice, eventually smoothing off the rough edges and creating a nearly perfect circle.
By the time we all got down to the river the ice circle had frozen in place, but there were actually two frozen ice disks nearly in contact with each other. One wheel, the recently rotating one, measured an estimated 25 feet in diameter, while the smaller one was about 15 feet across. I imagine one wheel formed first, eventually floated a bit downstream and froze into place, while another formed in its place.
If you’d like to learn more about how ice circles form, you can visit the Burlington Free Press's coverage on ice circles last year and even watch a video of it rotating in place (somewhat akin to watching paint dry).
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Global warming changes the flowering times of plants and the moment when bees hatch – sometimes with severe consequences for the bees. This was shown by a new study conducted by ecologists from the University of Würzburg.
There are around 550 different bee species in Germany. Most of them are solitary bees. They don't live in large beehives like the honeybee, but each female bee often builds multiple nests and feeds her offspring alone. Solitary bees use their short lifespan of a few weeks exclusively to reproduce and to provide food for their brood to develop into adult bees. Bees depend on the availability of pollen which they can frequently collect on specific plant species only.
The researchers studied three mason bee species. One of them was the red mason bee (Osmia bicornis).
Photo: Mariela Schenk
Well-timed hatching is crucial
Therefore, good timing is crucial when the insects hatch. This is particularly true in early spring when there is the risk that no plants are available to the bee if it has emerged from hibernation too early. As global warming may have a different impact on the time when different species emerge in spring, temporal mismatches may occur between bee and plant species.
What happens when a bee hatches before its food plants start to flower and it has to do without food during the first days of its life? A team of researchers from the Department of Animal Ecology and Tropical Biology of the University of Würzburg's Biocenter has looked into this question. The scientists present the results of their work in the Journal of Animal Biology.
Temporal mismatches harm bees
The Collaborative Research Center "Insect Timing" has investigated three different species of spring-emerging bees. The findings of their study are alarming: "Already a minor temporal mismatch of three or six days is enough to harm the bees," Mariela Schenk, the author of the study, explains.
For the purpose of the study, the researchers set up 36 large flight cages. This controlled environment allowed the scientists to make the bees hatch either simultaneously with the flowering of the plants in the cage or three and six days previously. Subsequently, they monitored the bees over their entire lifespan. The scientists recorded the daily activity of the bees and also how many nests and brood cells the bees produced.
What they found was that not all individuals survived three or six days without food plants.
And the ones that made it exhibited less activity and reduced reproductive output.
Negative consequences despite change in behaviour
These negative consequences occurred even though the insects had adopted several behavioural strategies to mitigate the impact. One of the three bee species, for example, tried to reduce the effort of providing for the young by producing fewer female and more male offspring. Male offspring requires less food than the much bigger young females. "But this approach could result in a decline in population," Mariela Schenk says.
Another bee species tried to save time in the production of offspring by distributing the same number of brood cells among fewer nests. This strategy, however, increases the risk that the entire brood falls prey to predators and parasites.
A further strategy one bee species adopted was to increase its activity in the second half of its life. But this method, too, was not sufficient to prevent negative consequences. Ecologist Mariela Schenk explains: "Although we found that the bee species we investigated developed species-specific strategies to mitigate the impact of temporal mismatches, the insects still suffered severe fitness loss."
Reduced plant pollination
Dr Andrea Holzschuh, who is also an ecologist and in charge of the study, adds: "Not only can such developments further exacerbate the decline of solitary bees, they can also reduce plant pollination in general." To make matters worse, the negative consequences of temporal mismatching of bees and plants seems to be particularly pronounced in very warm springs.
Mariela Schenk, Jochen Krauss, Andrea Holzschuh (2017) "Desynchronizations in bee-plant interactions cause severe fitness losses in solitary bees", Journal of Animal Ecology. doi: 10.1111/1365-2656.12694
Mariela Schenk, Department of Animal Ecology and Tropical Biology,
T: +49 931 31-89415; e-mail: firstname.lastname@example.org
Gunnar Bartsch | Julius-Maximilians-Universität Würzburg
O2 stable hydrogenases for applications
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The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
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To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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Seven papers that expand upon recent research into the origin of tetrapods and their invasion of the land during the Devonian period appear in the September/October 2004 issue of Physiological and Biochemical Zoology.
Although the fossil record of this transition remains far from complete, new discoveries have increased the resolution of the morphological sequence, documented the relative rapidity and geographic distribution of the tetrapod appearance, and fueled new controversy over the environmental and biological factors involved. Topics in this state-of-the-art issue range from the fish-tetrapod fossil record to diverse aspects of the behavior, physiology, biochemistry, and ecology of the extant fish species that use either or both terrestriality and air breathing.
Research findings include:
These articles are from two merged symposia ("How to Live Successfully on Land If One Is a Fish: The Functional Morphology and Physiology of the Vertebrate Invasion of the Land" and "Evolution of Air Breathing") presented at the Sixth International Congress of Comparative Physiology and Biochemistry, Mount Buller, Victoria, Australia, 2003.
Carrie Olivia Adams | EurekAlert!
O2 stable hydrogenases for applications
23.07.2018 | Max-Planck-Institut für Chemische Energiekonversion
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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03.07.2018 | Event News
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The largest particle accelerator in the world – the Large Hadron Collider at CERN in Switzerland – has a circumference of around 26 kilometres. Researchers at Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Germany, are attempting to go to the other extreme by building the world's smallest machine of this kind – a particle accelerator that fits on a microchip. The research team has now taken another step towards achieving this ambition.
The fundamental idea behind the miniature particle accelerator’s development is to enable scientists to use laser beams to accelerate electrons. What sounds deceptively simple in theory raises a whole series of challenges in practice, extending across various fields of physics.
For example, the scientists need to be able to control the oscillation of light and the movement of electrons with great precision in order to ensure that they meet each other at just the right moment.
One way of envisaging this is to imagine a ship on a stormy sea; to safely ascend the wave and come down on its other side, the helmsman has to watch the oncoming wave and judge when it will meet the vessel.
It is equally crucial for the FAU’s team of scientists to ascertain when and where the maximum crest of a light wave will hit a packet of electrons so that they can influence the outcome to a highly specific degree. This means they need to enable light and electrons to coincide within ‘attoseconds’ – that is, a billionth of a billionth of a second.
In an exciting first, this is exactly what the research group around FAU’s Prof. Dr. Peter Hommelhoff have succeeded in achieving. The team has developed a new technique involving the intersection of two laser beams oscillating at different frequencies in order to generate an optical field whose properties the researchers can influence to an extremely precise degree.
The key property of this optical field is that it retains contact with the electrons, effectively moving with them – hence its being termed a travelling wave – so the electrons can continuously sense, or ‘surf’, the optical field. In this way, the optical field transmits its properties exactly to the particles.
Not only does this process cause the particles to precisely reflect the field structure, it also accelerates them – to a strikingly high degree. This effect is crucial to the miniature particle accelerator’s practical application, as it relates to how much energy can be transferred to the electrons across what distance. The acceleration gradient, which indicates the maximum measured electron energy gain versus distance covered, reaches the extremely high value of 2.2 giga-electron-volts per metre, much higher than that attained by conventional accelerators.
However, the acceleration distance of only 0.01 millimetres currently available to the research team in Erlangen is not sufficient for them to generate the energy needed for achieving results of relevance to practical applications. ‘Despite this, for particle accelerators in medicine, we would only need a tiny acceleration length of less than a millimetre,’ explains Dr Martin Kozák, who carried out the laboratory experiment.
Particle accelerator on a microchip
Project lead Prof. Dr. Peter Hommelhoff of the Chair of Laser Physics at FAU considers accelerator miniaturisation to be a technical revolution analogous to the development of computers, which went from occupying entire rooms to fitting on people’s wrists. ‘This approach will hopefully enable us to make this innovative particle acceleration technique usable in a range of research areas and fields of application such as materials science, biology and medicine; one example might be particle therapies for cancer patients.’
In 2015, the FAU researchers teamed up with scientists from Stanford University and eight other international partner institutions in the Accelerator on a Chip International Program (ACHIP). The Gordon and Betty Moore Foundation has generously provided five years’ funding to the project; of the total grant of 13.5 million dollars (approximately 12.5 million euro), 2.44 million dollars (approximately 2.26 million euro) went to FAU.
The research team’s findings have now been published in the leading scientific journal Nature Physics (doi: 10.1038 / nphys4282).
Prof. Dr. Peter Hommelhoff
Phone: +49 9131 8527090
Dr. Susanne Langer | idw - Informationsdienst Wissenschaft
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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03.07.2018 | Event News
23.07.2018 | Health and Medicine
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Water retention on mathematical surfaces
Water retention on mathematical surfaces refers to the water caught in ponds on a surface of cells of various heights on a regular array such as a square lattice, where water is rained down on every cell in the system. The boundaries of the system are open and allow water to flow out. Water will be trapped in ponds, and eventually all ponds will fill to their maximum height, with any additional water flowing over spillways and out the boundaries of the system. The problem is to find the amount of water trapped or retained for a given surface. This has been studied extensively for two mathematical surfaces: magic squares and random surfaces. The model can also be applied to the triangular grid.
Magic squares have been studied for over 2000 years. In 2007, the idea of studying the water retention on a magic square was proposed. In 2010, Al Zimmermann's programing contest produced the presently known maximum retention values for magic squares order 4 to 28. Computing tools used to investigate and illustrate this problem are found here.
There are 4,211,744 different retention patterns for the 7x7 square. A combination of a lake and ponds is best for attaining maximum retention. No known patterns for maximum retention have an island in a pond or lake.
Maximum-retention magic squares for orders 7-9 are shown below:
The figures below show the 10x10 magic square. Is it possible to look at the patterns above and predict what the pattern for maximum retention for the 10x10 square will be? No theory has been developed that can predict the correct combination of lake and ponds for all orders, however some principles do apply. The first color-coded figure shows a design principle of how the largest available numbers are placed around the lake and ponds. The second and third figures show promising patterns that were tried but did not achieve maximum retention.
Several orders have more than one pattern for maximum retention. The figure below shows the two patterns for the 11x11 magic square with the apparent maximum retention of 3,492 units:
The most-perfect magic squares require all (n-1)^2 or in this case all 121 2x2 planar subsets to have the same sum. ( a few examples flagged with yellow background, red font). Areas completely surrounded by larger numbers are shown with a blue background.
Before 2010 if you wanted an example of a magic square larger than 5x5 you had to follow clever construction rules that provided very isolated examples. The 13x13 pandiagonal magic square below is such an example. Harry White's CompleteSquare Utility allows anyone to use the magic square as a potter would use a lump of clay. The second image shows a 14x14 magic square that was molded to form ponds that write the 1514 - 2014 dates. The animation notes how the surface was sculptured to fill all ponds to capacity before the water flows off the square. This square honors the 500th anniversary of Durer's famous magic square in Melencolia I.
The figure below is a 15x15 bordered magic square with zero water retention. This figure also provides an example of a square and its complement that have the same pattern of retention. There are 137 order 4 and 3,254,798 order 5 magic squares that do not retain water.
16 x 16 associative magic square retaining 17840 units. The lake in the first image looks a little uglier than common. Jarek Wroblewski notes that good patterns for maximum retention will have equal or near equal number of retaining cells on each peripheral edge ( in this case 7 cells on each edge) The second image is doctored, shading in the top and bottom 37 values.
The figure below is a 17x17 Luo-Shu format magic square. The Luo-Shu format construction method seems to produce a maximum number of ponds. The drainage path for the cell in green is long eventually spilling off the square at the yellow spillway cell.
The figure to the right shows what information can be derived from looking at the actual water content for each cell. Only the 144 values are highlighted to keep the square from looking too busy. Focusing on the green cell with a base value 7, the highest obstruction on the path out is its neighbor cell with the value of 151 (151-7=144 units retained). Water rained into this cell exits the square at the yellow 10 cell.
The computer age now allows for the exploration of the physical properties of magic squares of any order. The figure below shows the largest magic square studied in the contest. For L > 20 the number of variables/ equations increases to the point where it makes the pattern for maximum retention predictable.
|Jarek Wroblewski March 24, 2010|
This is a 32x32 panmagic square. Dwane Campbell using binary construction methods produced this interesting water retention example. The GET TYPE utility applied to this square shows that it has the following properties: 1) normal magic 2) pandiagonal 3) bent diagonal two way 4) self-complement.
Another system in which the retention question has been studied is a surface of random heights. Here one can map the random surface to site percolation, and each cell is mapped to a site on the underlying graph or lattice that represents the system. Using percolation theory, one can explain many properties of this system. It is an example of the invasion percolation model in which fluid is introduced in the system from any random site.
In hydrology, one is concerned with runoff and formation of catchments. The boundary between different drainage basin (watersheds in North America) forms a drainage divide with a fractal dimension of about 1.22.
The retention problem can be mapped to standard percolation. For a system of five equally probable levels, for example, the amount of water stored R5 is just the sum of the water stored in two-level systems R2(p) with varying fractions of levels p in the lowest state:
- R5 = R2(1/5) + R2(2/5) + R2(3/5) + R2(4/5)
Typical two-level systems 1,2 with p = 0.2, 0.4, 0.6, 0.8 are shown on the right (blue: wet, green: dry, yellow: spillways bordering wet sites). The net retention of a five-level system is the sum of all these. The top level traps no water because it is far above the percolation threshold for a square lattice, 0.592746.
The retention of a two-level system R2(p) is the amount of water connected to ponds that do not touch the boundary of the system. When p is above the critical percolation threshold p c, there will be a percolating cluster or pond that visits the entire system. The probability that a point belongs to the percolating or "infinite" cluster is written as P∞ in percolation theory, and it is related to R2(p) by R2(p)/L2 = p − P∞ where L is the size of the square. Thus, the retention of a multilevel system can be related to a well-known quantity in percolation theory.
To measure the retention, one can use a flooding algorithm in which water is introduced from the boundaries and floods through the lowest spillway as the level is raised. The retention is just the difference in the water level that a site was flooded minus the height of the terrain below it.
Besides the systems of discrete levels described above, one can make the terrain variable a continuous variable say from 0 to 1. Likewise, one can make the surface height itself be a continuous function of the spatial variables. In all cases, the basic concept of the mapping to an appropriate percolation system remains.
A curious result is that a square system of n discrete levels can retain more water than a system of n+1 levels, for sufficiently large order L > L*. This behavior can be understood through percolation theory, which can also be used to estimate L* ≈ (p - pc)−ν where ν = 4/3, p = i*/n where i* is the largest value of i such that i/n < pc, and pc = 0.592746 is the site percolation threshold for a square lattice. Numerical simulations give the following values of L*, which are extrapolated to non-integer values. For example, R2 < R3 for L ≤ 51, but R2 > R3 for L ≥ 52:
|n||n+1||L*||Retention at L*|
As n gets larger, crossing become less and less frequent, and the value of L* where crossing occurs is no longer a monotonic function of n.
The following time line shows the application of different algorithms that have expanded the size of the square that can be evaluated for retention
2007 Define all neighbor-avoiding walks from each interior cell to the exterior and then sort all those paths for the least obstruction or cell value. The least obstruction value minus the interior cell value provides the water retention for that interior cell (negative values are set to a retention value of 0). The number of neighbor-avoiding walks to be evaluated grows exponentially with the square size and thus limits this methodology to L < 6.
2009 Flooding algorithm - water is introduced from the boundaries and floods through the lowest spillway as the level is raised. The retention is just the difference in the water level that a site was flooded minus the height of the terrain below it. The flooding algorithm allows for the evaluation of water retention up to L < 10,000. This algorithm is similar to Meyer's flooding algorithm that has been used in analysis of topographical surfaces.
2011 With the realization that an n-level system can be broken down into a collection of two-level systems with varying probabilities, standard percolation algorithms can be used to find the retention as simply the total number of sites at the lower level minus the draining regions (clusters of low-level sites touching the boundary). A novel application of the Hoshen-Kopelman algorithm in which both rows and columns are added one at a time allows L to be very large (up to 109), but computing time considerations limits L to the order of 107.
Paths that drain water off the square, used in the neighbor-avoiding walk algorithm
The panel below from left to right shows: 1) the three unique interior positions for the 5x5 square; 2 & 4) correct paths off the square in grey for the interior corner cell in red; 3) incorrect path in grey as the water cannot travel on the diagonals; 5) this path is correct but there is a short-circuit possible between the grey cells. Neighbor-avoiding walks define the unique or non-redundant paths that drain water off the square.
- https://oeis.org/A303295 OEIS A303295
- Craig Knecht, http://www.knechtmagicsquare.paulscomputing.com
- Al Zimmermann http://www.azspcs.net/Contest/MagicWater/FinalReport
- Harvey Heinz, http://www.magic-squares.net/square-update-2.htm#Knecht
- Harry White, http://budshaw.ca/Download.html
- Walter Trump http://www.trump.de/magic-squares/
- Johan Ofverstedt,http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-176018
- Harry White, http://budshaw.ca/Most-perfect.html
- Sloane, N.J.A. (ed.). "Sequence A270205 (Number of 2 X 2 planar subsets in an n X n X n cube)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- Harvey Heinz,http://www.magic-squares.net/square-update.htm
- Chayes, J. T.; L. Chayes; C. M. Newman (1985). "The stochastic geometry of invasion percolation". Communications in Mathematical Physics. 101 (3): 383–407. Bibcode:1985CMaPh.101..383C. doi:10.1007/BF01216096.
- Damron, Michael; Artëm Sapozhnikov; Bálint Vágvölgyi (2009). "Relations between invasion percolation and critical percolation in two dimensions". Annals of Probability. 37 (6): 2297–2331. arXiv: . doi:10.1214/09-AOP462.
- van den Berg, Jacob; Antal Járai; Bálint Vágvölgyi (2007). "The size of a pond in 2D invasion percolation". Electron. Comm. In Probab. 12: 411–420. doi:10.1214/ECP.v12-1327.
- Tetzlaff, D.; McDonnell, J. J.; Uhlenbrook, S.; McGuire, K. J.; Bogaart, P. W.; Naef, F.; Baird, A. J.; Dunn, S. M.; Soulsby, C. (2011). "Conceptualizing catchment processes: simply too complex?". Hydrological Processes. 22 (11): 1727–1730. Bibcode:2008HyPr...22.1727T. doi:10.1002/hyp.7069.
- Fehr, E.; D. Kadau; N. A. M. Araújo; J. S. Andrade Jr; H. J. Herrmann (2011). "Scaling Relations for Watersheds". Physical Review E. 84 (3): 036116. arXiv: . Bibcode:2011PhRvE..84c6116F. doi:10.1103/PhysRevE.84.036116.
- Schrenk, K. J.; N. A. M. Araújo; J. S. Andrade Jr; H. J. Herrmann (2012). "Fracturing Ranked Surfaces". Scientific Reports. 2: 348. arXiv: . Bibcode:2012NatSR...2E.348S. doi:10.1038/srep00348. PMC . PMID 22470841.
- Fehr, E.; D. Kadau; J. S. Andrade Jr; H. J. Herrmann (2011). "Impact of Perturbations on Watersheds". Physical Review Letters. 106 (4): 048501. arXiv: . Bibcode:2011PhRvL.106d8501F. doi:10.1103/PhysRevLett.106.048501. PMID 21405368.
- Knecht, Craig; Walter Trump; Daniel ben-Avraham; Robert M. Ziff (2012). "Retention capacity of random surfaces". Physical Review Letters. 108 (4): 045703. arXiv: . Bibcode:2012PhRvL.108d5703K. doi:10.1103/PhysRevLett.108.045703.
- Baek, Seung Ki; Beom Jun Kim (2012). "Critical Condition of the Water-Retention Model". Physical Review E. 85: 032103. arXiv: . Bibcode:2012PhRvE..85c2103B. doi:10.1103/PhysRevE.85.032103.
- Schrenk, K. J.; N. A. M Araújo; R. M. Ziff; H. J. Herrmann (2014). "Retention capacity of correlated surfaces". Physical Review E. 89. arXiv: . Bibcode:2014PhRvE..89f2141S. doi:10.1103/PhysRevE.89.062141.
- Hoshen, Joseph (1998). "On the application of the enhanced Hoshen-Kopelman algorithm for image analysis". Pattern Recognition Letters. 19 (7): 575–584. doi:10.1016/S0167-8655(98)00018-x.
- Pickover, Clifford (2002). The Zen of Magic Squares, Circles, and Stars: An Exhibition of Surprising Structures Across Dimensions. Princeton, NJ: Princeton University Press. ISBN 0-691-11597-4.
- Stauffer, Dietrich; Aharony, A. (1994). Introduction to Percolation Theory. London Bristol, PA: Taylor & Francis. ISBN 978-0-7484-0253-3.
- Hugo Pfoertner. OEIS sequence A201126 (Maximum water retention of a magic square of order n), with links to magic square pictures
- Hugo Pfoertner. OEIS sequence A201127 (Maximum water retention of a semi-magic square of order n)
- Discussion site for the Zimmermann problems
- Item on Futility Closet
- OEIS sequence A261798 (Maximum water retention of an associative magic square of order n)
- OEIS sequence A268311 (Number of free polyominoes that form a continuous path of edge joined cells spanning an n X n square in both dimensions) -- Polyominoe enumeration and lake patterns
- OEIS sequence A275359 (Maximum incarceration of numbers in an n X n X n number cubes with full incarceration volumes) -- Upgrade the model from 2D to 3D | <urn:uuid:ecf80354-3d1f-44a2-a74e-29b0f89c4504> | 3.6875 | 3,758 | Knowledge Article | Science & Tech. | 71.638658 | 95,486,151 |
'Apple maggot' divergence is creating 3 new wasp species
The concept that biodiversity feeds upon itself is an old idea, but it's difficult to prove because it requires biologists to simultaneously catch several species red-handed just as they are becoming new species. Now biologists have proof.
A new study from biologists at Rice University, the University of Notre Dame, Michigan State University, the University of Iowa and the University of Florida finds that ongoing evolutionary changes in one fruit fly species are having a domino effect on at least three species of predatory wasps. The researchers focused on the jump of a native North American fruit fly onto apple trees in the 1850s.
"Our study addresses one of the central questions in biology: How do new forms of life originate?" said evolutionary biologist Scott Egan, assistant professor of biosciences at Rice and a co-author of the new study, which is available online in the Proceedings of the National Academy of Sciences.
The study follows up previous research by Egan and colleagues of the fruit fly Rhagoletis pomonella, aka the "apple maggot," which began plaguing U.S. apple growers in the 1850s. That work showed that changes in feeding and mating habits of Rhagoletis are driving it to become two different species.
"Our new work takes a close look at the evolutionary process termed 'sequential speciation,'" Egan said. "Sequential speciation identifies the fact that adaptation and speciation of one species is not an isolated process. The appearance of a new species creates new niche opportunities that can be exploited by other species, and that opportunity can promote the origin of other new species."
Rhagoletis is in the act of evolving into two species. The change is driven by differently timed fruiting cycles between apple trees, which some Rhagoletis prefer, and the North American hawthorn, the native fruit where Rhagoletis have traditionally laid their eggs. In extending their work on Rhagoletis speciation, the researchers focused on three species of wasps that are known parasites for Rhagoletis.
Wasps were collected from a number of different fly host plant environments in the wild. Analyses showed that all three wasp species were also in the process of diverging into two distinct species, both genetically and with respect to host-associated physiology and behavior.
"The new study extends the earlier work by showing that new fruit fly species provide suitable habitat not just for one new parasitoid species, but for multiple new species," said study co-author James Smith, a Michigan State entomologist.
These evolutionary changes, which are known as "sequential" or "cascading" events, may provide additional information to help biologists explain why certain organisms like plants and insects are more diverse and species-rich than other groups are.
"Why are there so many insect species?" Smith asked. "Speciation cascades provide one explanation for how a lot of species might be generated in a relatively short period of time."
Glen Hood, a Ph.D. student at Notre Dame and lead author of the paper, said, "Our study has impacted our understanding of evolution by suggesting that change in individual lineages can reverberate through different trophic levels of an ecosystem and increase community-level biodiversity."
Additional co-authors include Notre Dame's Jeffrey Feder, Iowa's Andrew Forbes and Gabriela Hamerlinck, and Florida's Thomas Powell. The research was supported by the National Science Foundation, the Indiana Academy of Science, the Entomological Society of America and Sigma Xi.
High-resolution IMAGES are available for download at:
CAPTION: The parasitic wasp, Utetes canaliculatus, on a snowberry shrub, searching for its Rhagoletis fly host.
CREDIT: Hannes Schuler
CAPTION: A Rhagoletis pomonella fly explores the derived host fruit, an apple.
CREDIT: Andrew Forbes
CAPTION: Scott Egan
CREDIT: Jeff Fitlow/Rice University
A copy of the PNAS paper is available at: http://www.
Related Rice research:
This release can be found online at news.rice.edu.
Follow Rice News and Media Relations via Twitter @RiceUNews
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,888 undergraduates and 2,610 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for best quality of life and for lots of race/class interaction by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance.
Jade Boyd | EurekAlert!
Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides
16.07.2018 | Tokyo Institute of Technology
The secret sulfate code that lets the bad Tau in
16.07.2018 | American Society for Biochemistry and Molecular Biology
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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|RHODOPHYTA : GIGARTINALES : Furcellariaceae||RED ALGAE|
Description: The foliose phase (gametangial) in the life-history grows from a small holdfast and short stipe to form one or more delicate fronds, flattened and thin. Fronds to 30 cms or more in length branching irregularly and from the margins. The tetrasporangial phase is crustose.
Habitat: Epilithic in the lower sublittoral to 25 m.
Distribution: Widespread, mainly western in the British Isles from the Shetlands to the Channel Islands. Europe: the Mediterranean, Spain, France, Denmark, Helgoland, Denmark and the Baltic. Further afield: Canary Islands and Morocco.
Similar Species: The tetrasporophyte is crustose and very difficult to distinguish from other encrusting algae. The gametophyte is very similar to Halymenia latifolia and some other red foliose red algae.
Key Identification Features:
Distribution Map from NBN: Interactive map : National Biodiversity Network mapping facility, data for UK.
WoRMS: Species record : World Register of Marine Species.
|Morton, O. & Picton, B.E. (2016). Halarachnion ligulatum (Woodward) Kützing. [In] Encyclopedia of Marine Life of Britain and Ireland. |
http://www.habitas.org.uk/marinelife/species.asp?item=ZM6480 Accessed on 2018-07-18
|Copyright © National Museums of Northern Ireland, 2002-2015| | <urn:uuid:406b802e-eed3-4a60-bdac-c5503eb5327e> | 2.90625 | 355 | Knowledge Article | Science & Tech. | 33.839037 | 95,486,176 |
The Indian Lunar Exploration Programme (Sanskrit: चन्द्रयान Chandrayāna, lit: Moon vehicle pronunciation (help·info)), also known as the Chandrayaan programme, is an ongoing series of outer space missions by the Indian Space Research Organisation (ISRO). The programme incorporates a lunar orbiter and future lunar lander & rover spacecraft.
The Chandrayaan (Indian Lunar Exploration Programme) programme is a multiple mission programme; as of mid-2016 only one orbiter has been sent to the Moon, using ISRO's workhorse PSLV rocket. The second spacecraft is being readied for a late 2016-early 2017 launch using the GSLV rocket.
Phase I: Orbital missions
The first phase includes the launch of the first lunar orbiters.
- Chandrayaan-1, launched on 22 October 2008 aboard a PSLV-XL rocket, was a big success for ISRO as the Moon Impact Probe, a payload on board the Chandrayaan-1 spacecraft, discovered water on the Moon. Apart from discovering water the Chandrayaan-1 mission performed several other tasks such as mapping and atmospheric profiling of the Moon.
Phase II: Soft landers/rovers
The second phase, under preparation as of 2018, will incorporate spacecraft capable of soft-landing on the Moon and will also deploy a robotic rover on the lunar surface.
- Chandrayaan-2 is to be launched in the first quarter of 2018 aboard the heavy–duty GSLV Mk II rocket. | <urn:uuid:f52b41dc-46c5-4d37-a0fa-f78508578644> | 3.390625 | 319 | Knowledge Article | Science & Tech. | 44.853135 | 95,486,193 |
Another day, another way nature forces us to change something fundamental about how we see the world.
Scientists have long assumed that all fish are basically cold-blooded. Sure, there are some limited exceptions: tuna, great white sharks and a few others can warm up parts of their body a bit when they vigorously swim. Generally, though, fish that live in the deep cold water of the sea were thought to be exclusively sluggish and slow-moving.
Naturally, then, biologist Nick Wegner of the National Oceanic and Atmospheric Administration's Southwest Fisheries Science Center in La Jolla, Calif., assumed that a large silvery fish called opah, which hangs out in the depths, was cold and lethargic.
This turned out to be wrong, and researchers have discovered that the opah can actually continually keep its whole body, including its heart and brain, warm. This ability, known as endothermy, was thought to be unique to mammals and birds. A warm body temperature allows these animals to have a higher metabolism, and a better-performing brain and more active muscles, according to the study.
“Because the opah can warm its body, it turns out to be a very active predator that chases down agile prey like squid and can migrate long distances,” Wegnersaid in a statement.
In a study published today in the journal Science, Wegner and colleagues found that opahs produce heat by continually flapping their wing-like pectoral fins. This movement generates warmth in the fish’s enormous pectoral muscles, which take up nearly one sixth of its body mass.
Opahs also have an ingenious way of conserving and circulating this heat, Wegner says. The veins leaving the muscles with warm blood are wrapped around those leaving the gills, carrying cold blood. This heats up the colder blood, and limits loss of heat. This actually looks a lot like a design humans use to warm or cool things, called a “counter-current heat exchange,” found for example in car radiators. It’s amazing that this setup was “invented in fish long before we thought of it,” Wegner says.
“Nature has a way of surprising us with clever strategies where you least expect them,” he adds.
Nick Wegner and an opah.NOAA FISHERIES/SOUTHWEST FISHERIES SCIENCE CENTER
Povos indígenas no estado de Rondônia
Aikanã, Ajuru, Amondawa, Arara, Arikapu, Ariken, Aruá, Cinta Larga, Gavião, Jabuti, Kanoê, Karipuna, Karitiana, Kaxarari, Koiaiá, Kujubim, Makuráp, Mekén, Mutum, Nambikwara, Pakaanova, Paumelenho, Sakurabiat, Suruí, Tupari, Uru Eu Wau Wau, Urubu, Urupá
A população da Terra indígena Uru-Eu-Wau-Wau é composta por vários subgrupos, como: Jupaú, Amondawa e Uru Pa In. Encontram-se distribuídos em 6 aldeias, nos limites da Terra Indígena, por questões de proteção e vigilância. Além destas etnias, há presença de índios isolados como os Parakuara e os Jurureís.
Os Jupaú traduzem sua autodenominação como "os que usam jenipapo". A denominação "Uru-eu-wau-wau" foi dada aos Jupaú pelos índios Oro-Uari.
Muitos foram os nomes atribuídos aos Uru-Eu-Wau-Wau. As denominações Bocas-Negras, Bocas-Pretas, Cautários, Sotérios, Cabeça-Vermelha, são encontradas na historiografia e estão relacionadas ao espaço geográfico ou a se… | <urn:uuid:5bd6ea94-a846-4f9e-9c01-c460c630fb4a> | 3.734375 | 948 | Personal Blog | Science & Tech. | 34.755593 | 95,486,194 |
Butterfly: Wingspan: 1 to 1 1/4 inches (2.5-3.2 cm). Light gray with black and white line across both wings. The hindwing has a red-capped black spot and blue scaling above the tails. Upper surfaces are gray with a red-capped black spot above the tail. Top of head and tip of antennae are orange. Male abdomen is orange; female abdomen is gray. Females tend to be larger.
ID Tip: True gray—not gray-brown. The color is important.
Egg: Light green, laid singly; often on or near flower buds of host.
Caterpillar: Although generally some shade of green, color varies according to host plant hue.
Chrysalis: Dark brown. The over-wintering stage.
Gray Hairstreaks are the most commonly encountered hairstreaks in Alabama and will eventually be documented in every county in the state. In fact, Gray Hairstreaks are so widespread that it is easy to become complacent about their striking beauty. The crisp clear gray of this butterfly sparkles!
Gray Hairstreaks are consummate habitat generalists, requiring little more than plants and sunlight. Their caterpillars have adapted to eat from more than 30 plant families, although legumes and mallows are most frequently chosen. As common and widespread as these butterflies are, they are seldom seen in large numbers. Most field trip lists record one or two.
A dot on the county map indicates that there is at least one documented record of the species within that county. In some cases, a species may be common throughout the county, in others it may be found in only a specific habitat.
The sightings bar graphs depict the timing of flight(s) within each of three geographic regions. Place your cursor on a bar within the graph to see the number of individuals recorded during that period.
The abundance calendar displays the total number of individuals recorded within each week of the month. Both the graphs and the calendar are on based data collection that began in 2000.
The records analyzed here are only a beginning. As more data is collected, these maps and graphs will paint a more accurate picture of distribution and abundance in Alabama. Submit your sightings to firstname.lastname@example.org.
Sightings in the following counties: Autauga, Baldwin, Barbour, Bibb, Bullock, Butler, Chambers , Cherokee, Chilton, Clay, Cleburne, Coffee, Colbert, Coosa, Covington, Crenshaw, Cullman, Dallas, DeKalb, Elmore, Escambia, Etowah, Fayette, Franklin, Hale, Henry, Jackson, Jefferson, Lamar, Lawrence, Lee, Lowndes, Macon, Madison, Marengo, Marion, Marshall, Mobile, Montgomery, Perry, Pickens, Pike, Randolph, Shelby, St. Clair, Sumter, Tallapoosa, Tuscaloosa, Walker, Wilcox, Winston
View county names by moving the mouse over a county or view a map with county names
Food plants represent more than 30 plant families, but the Pea family (Fabaceae) may be most common.
These plants have been verified in Alabama: Common Partridge Pea (Chamaecrista fasciculata), Hogwort/Wooly Croton (Croton capitatus), White Clover (Trifolium reptans), Okra (Abelmoschus esculentus), Downy Milk Pea (Galactia volubilis), Curly Dock (Rumex crispus).
For more information about the documented host plants and/or nectar plants, please visit the Alabama Plant Atlas using the following links:
Gray Hairstreaks are among the butterflies that benefit from including Partridge Pea (Chamaecrista fasciculata) in the landscape. They nectar from a variety of small flowers including milkweeds (Asclepias spp.), mountain mints (Pycnanthem spp.) and goldenrods (Solidago spp.), all wonderful landscape plants that benefit many butterfly species. | <urn:uuid:9ef67f79-7903-4d7e-8a3e-59db8ea2fd14> | 3.21875 | 860 | Knowledge Article | Science & Tech. | 44.137227 | 95,486,200 |
Butterfly: Wingspan: 1 1/4 to 1 5/8 inches (3.2-4.1 cm). A small yellow butterfly with black wingtips and a black bar along the lower margin of the forewings. In females, this bar is faint or almost absent. The upperside of the hindwing usually has a black band around the outside margin. Females are typically lighter than males and are sometimes almost white. This species also exhibits considerable seasonal variation. Summer/wet season butterflies are generally paler and smaller. Winter/dry season individuals display brick-red scaling on their wings. Barred Yellows exhibit so many different markings and color forms that respected lepidopterist/author Rick Cech suggests “Variable Sulphur” as a more appropriate name.
ID Tip: Black bar on lower edge of dorsal (upper surface) forewing. Bottom of hindwing is angled rather than rounded.
Egg: Pale, spindle-shaped eggs are deposited singly on host plant.
Caterpillar: Caterpillars are green with narrow, white side stripes and very short hairs.
Chrysalis: Chrysalides are green with faint dark markings and a faint white and black line near the head and thorax. They may sometimes be highly patterned. Chrysalides appear somewhat flattened and have a short point on the head. Often formed on the host plant.
Barred Sulphurs are not year-round residents of Alabama and are seldom common. They are not adapted to withstand freezing temperatures and recolonize from Florida each year. Not expected in spring, look for a rise in population as the year progresses.
Barred Sulphur males are typically seen actively patrolling for females. Courtship is an amazing sight! An amorous male sidles up to a potential female partner and unhinges a forewing and then proceeds to wave it in her face while simultaneously releasing sex-inducing pheromones. If she is previously unmated and sufficiently impressed, mating occurs. Freshly emerged males engage in puddling behavior.
A dot on the county map indicates that there is at least one documented record of the species within that county. In some cases, a species may be common throughout the county, in others it may be found in only a specific habitat.
The sightings bar graphs depict the timing of flight(s) within each of three geographic regions. Place your cursor on a bar within the graph to see the number of individuals recorded during that period.
The abundance calendar displays the total number of individuals recorded within each week of the month. Both the graphs and the calendar are on based data collection that began in 2000.
The records analyzed here are only a beginning. As more data is collected, these maps and graphs will paint a more accurate picture of distribution and abundance in Alabama. Submit your sightings to email@example.com.
Sightings in the following counties: Baldwin, Bibb, Bullock, Chambers, Chambers , Choctaw, Clay, Covington, Dallas, Elmore , Geneva, Hale, Henry, Houston, Jefferson, Macon, Monroe, Perry, Pike, Shelby, Talladega, Wilcox
View county names by moving the mouse over a county or view a map with county names
In south Alabama, Barred Yellows may be found in coastal sand dunes and dry coastal-plain pine woodlands. In other parts of the state, they are usually found in disturbed, open areas that include roadsides, vacant lots, and sometimes gardens.
Members of the Pea family (Fabaceae), especially pencil-flowers (Stylosanthes spp.) and joint-vetches (Aeschynomene spp.) are typically reported.
This host plant has been verified in Alabama: Side Beak Pencil Flower (Stylosanthes biflora).
For more information about the documented host plants and/or nectar plants, please visit the Alabama Plant Atlas using the following links:
Natural lawns that contain small flowering plants like clover, frogfruit, and violets provide nectar sources for many small butterflies including Barred Yellows. Pencil Flower, a typical host plant, will also grow in a natural lawn. | <urn:uuid:05983e20-fd69-4534-857a-a315e5d8b9af> | 3.375 | 880 | Knowledge Article | Science & Tech. | 42.517547 | 95,486,201 |
Browse through this collection of internet resources drawn from the SERC catalog based on their relevance to the Deep Earth and/or teaching about it.
Imagining Earth's Interior
This image from the COMPRES galleries show a dozen conceptions of the structure of the deep earth. The composite image is by Ed Garnero.
Links to Mineral Physics
This chart shows how mineral physics can be an important part of both research and education across the geology curriculum.
This image is of a diamond anvil used in high pressure deformation experiments. This particular diamond was created using the chemical vapor deposition (CVD) method. These artificial diamonds have ...
Water in the Mantle
This schematic shows a cross-section of the planet and how water can migrate through the deep interior of the Earth. Blue arrows indicate a movement of water downward, yellow arrows indicated ...
This diagram associates parts of the Earth's interior with particular kinds of experimental apparatus which can recreate it's pressure and temperature conditions.
Minerals in Earth's Mantle
This image from the COMPRES galleries shows the various mineral species that make up the composition of the mantle and how that composition varies with depth down to the core-mantle boundary.
Capabilities of Experimental Apparatus
This diagram displays the pressure/temperature conditions capable of being simulated with two types of experimental equipment: Piston-Cylinder and USSA-2000. The ranges of conditions are plotted on a ...
The Earth's Mantle
This illustration from Kellog, Hader, and van der Hilst (1999) shows their vision of a chemically stratified mantle perturbed by the downgoing subducted slabs of oceanic lithospere (blue).
This image is a schematic of a D-DIA apparatus used for mineral deformation experiments at high temperature and pressure.
Mineralogy of Earth's Structure
Cartoon cross section of a subduction zone showing the principal mineralogy of the upper 800 km of Earth's mantle. Arc volcanism at the surface is depicted, as are upper mantle earthquakes (red ...
Numerical Models of the Geodynamo
This page from Peter Olson at Johns Hopkins University describes recent geomagnetic research. The page includes several illustrations and an animation of geomagnetic reversal.
The truth about Earth's core?
This page uses the 1998 movie The Core (1998) to introduce what we actually know or suspect is true about the Earth's core. Includes discussion of current theories and mysteries from Rich ... | <urn:uuid:58625ca0-7db3-4211-bb36-a041d0342a42> | 3.09375 | 512 | Content Listing | Science & Tech. | 40.526853 | 95,486,228 |
Database: A database is a large collection of data or information to stored in our computer in an arranged way. It helps us for accessing, managing and updating the data easily. In this example we are using MySQL database, which is a RDBMS. A RDBMS (Relational Database Management System) is a type of DBMS (Database Management System) which stores the data in the form of tables. RDBMS is very powerful as it doesn't need to aware how the data is related or how it is going to be extracted from the database. So, we can view the same database in many different ways.
Table: A table is basic component of database (DB) that has number of rows and columns. All tables are stored in a specific database.
Here we are providing you an example with code and it's description that helps you to create a database table by using java file. Brief description given below:
Description of program:
Firstly in this program we are going to establish the connection with database and creating a table with some fields. If table name already exists then we are displaying the message "Table already exists!".
Description of code:
It is a interface. Statement object executes the SQL statement and returns the result it produces.
It is a method of Connection interface. which returns Statement object. This method will compile again and again whenever the program runs.
JDBC Video Tutorial: Creating database table from Java Program
CREATE TABLE table_name(field_name):
An appropriate code used for creating a table with given field name.
This method also executes SQL statement that may be INSERT, UPDATE OR DELETE statement are used in the code. It takes string types parameters for SQL statement. It returns int.
Here is the code of program: | <urn:uuid:d2c9295a-e92d-43ae-95f2-6e57e6fbf696> | 3.421875 | 365 | Documentation | Software Dev. | 44.478333 | 95,486,234 |
Gray wolves, or timber wolves, are canines with long bushy tails that are often black-tipped. Their coat color is typically a mix of gray and brown with buffy facial markings and undersides, but the color can vary from solid white to brown or black. Gray wolves look somewhat like a large German shepherd. Wolves vary in size depending on where they live. Wolves in the north are usually larger than those in the south. The average size of a wolf's body is three to five feet long and their tails are usually one to two feet long. Females typically weigh 60 to 100 pounds, and males weigh 70 to 145 pounds.
The historic range of the gray wolf covered over two-thirds of the United States. Today gray wolves have populations in Alaska, northern Michigan, northern Wisconsin, western Montana, northern Idaho, northeast Oregon, and the Yellowstone area of Wyoming. Mexican wolves, a subspecies of the gray wolf, were reintroduced to protected parkland in eastern Arizona and southwest New Mexico. Wolves can thrive in a diversity of habitats from the tundra to woodlands, forests, grasslands and deserts.
Wolves are carnivores—they prefer to eat large hoofed mammals such as deer, elk, bison, and moose. They also hunt smaller mammals such as beavers, rodents, and hares. Adults can eat 20 pounds of meat in a single meal.
Wolves communicate through body language, scent marking, barking, growling, and howling. Much of their communication is about reinforcing the social hierarchy of the pack. When a wolf wants to show that it is submissive to another wolf, it will crouch, whimper, tuck in its tail, lick the other wolf's mouth, or roll over on its back. When a wolf wants to challenge another wolf, it will growl or lay its ears back on its head. A playful wolf dances and bows. Barking is used as a warning, and howling is for long-distance communication to pull a pack back together and to keep strangers away.
Wolves live in packs. Most packs have four to nine members, but the size can range from as few as two wolves to as many as 15. Occasionally a pack can increase to 30 members, until some individuals break off to find new territory and form their own pack.
Within the pack hierarchy, there are male and female hierarchies. The alpha male is dominant over the entire pack, both males and females. The alpha female and male are the only ones that breed.
When the young adults reach the age of three, they can either join the pack or leave to find their own territory. The new territory can be close by if there is a lot of prey. In some areas, young adults travel hundreds of miles to find a new territory.
Wolves typically mate for life. In the northern United States, they breed from late January through March. The breeding season is earlier for wolves living farther south. Wolves are pregnant for about 63 days and usually birth four to six pups.
The wolf pups are usually born in a den. At birth, they cannot see or hear and weigh about one pound. The pups are weaned at about six weeks. Adult pack members swallow meat and bring it back to the den for their pups. After the adults regurgitate the food, the pups have a hearty meal. The mother wolf moves her pups to new den sites every couple of months until the fall, when the pack stops living at den sites. In the wild, wolves live 8 to 13 years, sometimes more. In captivity, they live upward of 15 years.
The gray wolf's story is one of the most compelling tales of American wildlife. Once, the wolf was widespread across most of North America, but it was hunted ruthlessly and extirpated over most of its range. Today the wolf is making a successful comeback in some of its former habitat due to strong conservation efforts. The gray wolf plays a vital role in the health and proper functioning of ecosystems.
Wolf packs usually hunt within a territory. Territories can range from 50 square miles to over a 1,000 square miles. Wolves travel as far as they need to in order to find prey. They often travel at five miles an hour, but can reach speeds of 40 miles an hour.
Place your order today for the themed box that delivers everything you need to create family memories while discovering nature and wildlife.Read More
Find out what it means to source wood sustainably, and see how your favorite furniture brands rank based on their wood sourcing policies, goals, and practices.Read More
Climate change is allowing ticks to survive in greater numbers and expand their range—influencing the survival of their hosts and the bacteria that cause the diseases they carry.Read More
Tell your members of Congress to save America's vulnerable wildlife by supporting the Recovering America's Wildlife Act.Read More
You don't have to travel far to join us for an event. Attend an upcoming event with one of our regional centers or affiliates. | <urn:uuid:c8864e53-476e-4aa0-bf47-afc0aca01632> | 3.546875 | 1,034 | Knowledge Article | Science & Tech. | 58.973727 | 95,486,241 |
Projected Range Contractions of European Protected Oceanic Montane Plant Communities: Focus on Climate Change Impacts Is Essential for Their Future Conservation
Hodd, Rory L.
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Hodd, R.L. Bourke, D and Sheehy Skeffington, M (2014) 'Projected Range Contractions of European Protected Oceanic Montane Plant Communities: Focus on Climate Change Impacts Is Essential for Their Future Conservation'. Plos One, 9 (4).
Global climate is rapidly changing and while many studies have investigated the potential impacts of this on the distribution of montane plant species and communities, few have focused on those with oceanic montane affinities. In Europe, highly sensitive bryophyte species reach their optimum occurrence, highest diversity and abundance in the north-west hyperoceanic regions, while a number of montane vascular plant species occur here at the edge of their range. This study evaluates the potential impact of climate change on the distribution of these species and assesses the implications for EU Habitats Directive-protected oceanic montane plant communities. We applied an ensemble of species distribution modelling techniques, using atlas data of 30 vascular plant and bryophyte species, to calculate range changes under projected future climate change. The future effectiveness of the protected area network to conserve these species was evaluated using gap analysis. We found that the majority of these montane species are projected to lose suitable climate space, primarily at lower altitudes, or that areas of suitable climate will principally shift northwards. In particular, rare oceanic montane bryophytes have poor dispersal capacity and are likely to be especially vulnerable to contractions in their current climate space. Significantly different projected range change responses were found between 1) oceanic montane bryophytes and vascular plants; 2) species belonging to different montane plant communities; 3) species categorised according to different biomes and eastern limit classifications. The inclusion of topographical variables in addition to climate, significantly improved the statistical and spatial performance of models. The current protected area network is projected to become less effective, especially for specialised arctic-montane species, posing a challenge to conserving oceanic montane plant communities. Conservation management plans need significantly greater focus on potential climate change impacts, including models with higher-resolution species distribution and environmental data, to aid these communities' long-term survival.
This item is available under the Attribution-NonCommercial-NoDerivs 3.0 Ireland. No item may be reproduced for commercial purposes. Please refer to the publisher's URL where this is made available, or to notes contained in the item itself. Other terms may apply.
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Cracking the catalytic codeBy Steve Koppes • April 24, 2018
The newly developed ability to tap previously inaccessible shale gas deposits during the last decade has created an abundant source of gases, including methane, ethane and propane, that are used to create chemical-based products such as plastics. But the U.S. chemical industry needs scientists, including those at the U.S. Department of Energy’s (DOE) Argonne National Laboratory, to help turn that new feedstock supply into a competitive technological advantage.
In a variety of research programs, Argonne experts are finding ways to more cheaply and efficiently manufacture products derived from shale gas deposits and are identifying new routes to make higher-performance catalysts.
“One of the main goals is to transfer the knowledge from the basic energy sciences side to the markets.” — Max Delferro, chemist and group leader, Argonne Catalysis Group
“In order to maximize the benefits and take advantage of today’s inexpensive source of natural gas and natural gas liquids to create investments and jobs in the United States, it is important to develop new and more efficient processes related to catalytic conversion of natural gas to higher-value materials,” asserted a 2016 report of the National Academy of Sciences.
Shale gas is a natural gas found in shale rock formations created hundreds of millions of years ago. The wet part of shale gas contains a variety of alkanes, a family of commercially important hydrocarbons that includes ethane and propane. The chemical industry is interested in alkanes that can be converted into alkenes — a class of hydrocarbons useful in manufacturing a variety of materials, mostly polymers such as polyethylene and polypropylene. Argonne’s catalysis science program has already developed a successful method for effectively converting alkanes to alkenes. Now, the researchers also investigate how they can make other compounds of interest to the chemical industry.
“The goal is to understand how to manipulate single-site catalysts on surfaces and how we can achieve high selectivity for light alkane transformation to added-value products such as olefins, which have found widespread use in the manufacturing industry,” said Max Delferro, an Argonne chemist who leads the laboratory’s catalysis group.
Argonne scientists focus much of their work on single-site catalysts because of the promise they show for both high activity and product selectivity. Such work has resulted in two U.S. patent applications for the development of multi-metallic catalysts that selectively dehydrogenate n-butane to 1,3-butadiene (BDE). BDE is a primary building block of synthetic rubber, which polymer manufacturers have used to make car tires.
Current process technologies for converting alkanes to alkenes all involve coking, a carbon-deposition process that interferes with catalytic activity. “The problem with coking is that you’re not converting your feedstock to the product you want. You’re converting it to a byproduct,” said Ted Krause, a chemical engineer and department head in Argonne’s Chemical Sciences and Engineering division. Argonne’s single-site catalyst technology dehydrogenates alkanes without promoting coking.
The work targets a range of catalysts and reactions from which private companies might select for optimization and commercialization. “One of the main goals is to transfer the knowledge from the basic energy sciences side to the markets,” said Delferro.
Krause leads a second project, funded through DOE’s Office of Energy Efficiency and Renewable Energy (EERE) Bioenergy Technologies Office. In this project, researchers use X-ray spectroscopy at the Advanced Photon Source (APS), a DOE Office of Science User Facility, to understand how catalysts react and how they deactivate.
Argonne’s catalysis scientists are working with several companies in the biofuels and biochemical industry through cooperative agreements to spur the development of catalytic materials. In APS experiments, Argonne researchers probe catalytic reactions with an X-ray beam to monitor the changes that catalysts undergo during actual working conditions.
Catalysis science has been an APS mainstay since the APS began operation in 1996. In situ and operando experimentation capabilities are an important strength of the APS, enabling measurements under real-world conditions, said Greg Halder, business development executive in Argonne’s Technology Commercialization and Partnerships division.
“These approaches span a suite of beamlines that allow industry to watch reactions happen in real time and measure catalytic performance by precisely monitoring a range of chemical and physical properties,” Halder said. “This information can then be combined with experimental and computational data and expertise to develop the next generation of catalysts.”
Argonne researchers specialize in understanding why catalysts deactivate — why they die — and in developing techniques to mitigate that process.
“Catalyst lifetime is a critical cost factor,” Krause said. “If it’s short, you need a regeneration process, because the cost of exchanging it with fresh catalyst could be prohibitive. Even for long-term catalysts, as they begin to deactivate with time, you tend to lose selectivity to the desired product, so you tend to make less of your desired product.”
Chris Marshall, a senior research chemist in the catalysis group, leads a DOE EERE Advanced Manufacturing Office-funded project to develop capabilities for extending catalyst lifetime. “We’ve developed techniques for stabilizing catalysts, particularly under harsh reaction conditions,” Krause said.
In addition to its expertise, Argonne is equipped with infrastructure that accelerates the discovery of both materials and process conditions. The laboratory’s catalyst tool for atomic layer deposition synthesis offers precise control over the process at the atomic level, and Argonne’s high-throughput robotic synthesis platform screens multiple catalysts simultaneously for a wide variety of reactions and reaction conditions.
For information about collaborative opportunities with Argonne’s catalysis science program, contact Greg Halder at firstname.lastname@example.org, or 630-252-5382.
The U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (EERE) supports early-stage research and development of energy efficiency and renewable energy technologies that make energy more affordable and strengthen the reliability, resilience, and security of the U.S. electric grid.
EERE's Advanced Manufacturing Office (AMO) supports early-stage research to advance innovation in U.S. manufacturing and promote American economic growth and energy security.
Argonne National Laboratory seeks solutions to pressing national problems in science and technology. The nation's first national laboratory, Argonne conducts leading-edge basic and applied scientific research in virtually every scientific discipline. Argonne researchers work closely with researchers from hundreds of companies, universities, and federal, state and municipal agencies to help them solve their specific problems, advance America's scientific leadership and prepare the nation for a better future. With employees from more than 60 nations, Argonne is managed by UChicago Argonne, LLC for the U.S. Department of Energy's Office of Science.
The U.S. Department of Energy's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information, visit the Office of Science website. | <urn:uuid:3c87c9c4-9358-4123-8493-a1b375902e78> | 2.96875 | 1,565 | News (Org.) | Science & Tech. | 19.091973 | 95,486,248 |
Ground water and tundra fires may work together to thaw permafrost, study says
Montreal and Victoria – Ground water may play an unrecognized role in thawing Arctic permafrost following wildfires, according to new Canadian-led research.
A new study indicates that, after wildfire burns off a portion of organic rich soil that normally insulates permafrost, summer warmth penetrates deeper into the frozen soils, allowing ground water to flow downgradient and potentially contributing to greater release of greenhouse gases, the Geological Society of America said in a news release.
The study's lead author, ecohydrologist Samuel Zipper from McGill University and the University of Victoria, shared his findings on Oct. 22 at the Geological Society of America Annual Meeting in Seattle, Wash.
Conventionally, Zipper said in the release, researchers tend to estimate permafrost thaw by vertically measuring thawed soil depth at single locations, offering a one-dimensional perspective of the aftereffects of fire on the Arctic landscape.
Instead, he suspected that ground water might play an unrecognized role in the process, where it thaws permafrost in other areas after flowing through once-frozen soils. Once wildfire burns through the organic-rich soil that usually insulates permafrost, summertime temperatures can reach deeper into the frozen ground, contributing to even greater thaw.
"What's interesting to me," Zipper said, "is if you burn one location, how do other parts of the landscape respond to that fire? Can ground water flow transmit the impacts of burning from one spot to another by moving water and heat through the subsurface?"
To explore the question, Zipper and his colleagues ran over 20,000 simulations of the largest Tundra fire in recorded history: Alaska's Anaktuvuk River Fire, which scorched over 400 square miles. They ran simulations both with and without ground water flow to tease out its contribution to permafrost thaw following fires. Zipper suspected that, after summertime temperatures penetrate the permafrost, ground water would flow more rapidly, delivering a greater amount of water into nearby streams.
They found that, indeed, wildfire does lead to deeper permafrost thaw, which is enhanced by ground water flow. But, surprisingly, more water evaporated following fire, so there was less overall ground water flow reaching the stream.
"Even though the water was able to flow more rapidly," Zipper said, "there was actually less water being supplied to the subsurface because of this change in evaporation. We found this kind of interesting dynamic where there was more room for water to flow, but less water available to flow."
Additionally, the results suggest that wildfire may trigger a positive feedback loop of permafrost thaw. When permafrost thaws simply from the Sun's warmth, ground water flows from the thawed soil into more permafrost, melting it, which releases more ground water to thaw more permafrost. Zipper suspects that fire could prematurely set this loop into motion and intensify its effects.
To follow up on the results of the study, Zipper plans to work with data from more Alaskan field sites, which will help him determine the pervasiveness of the phenomenon. "We want to know, how real and widespread is this process?"
Permafrost contains many organic compounds left by long-dead but not degraded frozen plants. Thawing permafrost releases greenhouse gases from those compounds into the atmosphere, which further intensifies warming. The Arctic is among the most rapidly warming regions on Earth, and hotter summers tend to bring more fire-prone vegetation, according to Zipper.
To properly manage and protect these landscapes, Zipper said it's important to form a complete picture of their response to fire, and incorporating ground water into that picture is essential.
"Our findings show that you can't really understand how permafrost is going to respond to disturbances like fire without understanding what's happening in the ground water system," Zipper said. "Ground water is a component of the Arctic's water cycle that's been under appreciated just for lack of data. It's kind of the next frontier for figuring out what's going to happen in the Arctic’s future."
South Atlantic Jubilee
July 28-30, 2018
ICID International Conference and Executive Council Meeting
August 12-17, 2018
PFAS in Groundwater Workshop: The Professional’s Challenge
August 14-15, 2018
Protect Your Groundwater Day
September 4, 2018
OGWA golf tournament
September 21, 2018
Atlantic Ground Water Association Fall Convention
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Solvents are omnipresent in the chemical industry, and are a major environmental and safety concern. Therefore the large interest in mechanochemistry: an energy-efficient alternative that avoids using bulk solvents and uses high-frequency milling to drive reactions.
The experimental setup at the ESRF in Grenoble (France) with the milling jar containing the white ZIF-8 shown in the front, mounted on a modified industrial mill. The X-rays enter at the yellow circle, and the X-ray detector is set several meters behind the viewer. The robot with the screw driver to push the buttons was devised by Frank Adams, team member from MPI for Solid State Research in Stuttgart, is positioned above the mill and enables remote control. This is necessary because of the lethal level of X-rays during the experiment, which takes places inside a cabin shielded by several centimetres of lead.
Credit: Credit T. Frišèiæ
Milling is achieved by the intense impact of steel balls in a rapidly moving jar, which hinders the direct observation of underlying chemistry. Scientists have now for the first time studied a milling reaction in real time, using highly penetrating X-rays to observe the surprisingly rapid transformations as the mill mixes, grinds and transforms simple ingredients into a complex product. This study opens new opportunities in Green Chemistry and environmentally-friendly synthesis. The results are published in Nature Chemistry dated 2 December 2012.The international team of scientists was led by Tomislav Friščić of McGill University (Canada) in collaboration with Ivan Halasz from the University of Zagreb (Croatia), scientists from the University of Cambridge (UK), Max-Planck-Institute for Solid State Research in Stuttgart (Germany) and the European Synchrotron Radiation Facility (ESRF) in Grenoble (France).
Although it is well known that mechanical action can break chemical bonds, for example in tear and wear of textile fibres, it is much less known that mechanical force can also be used to synthesize new chemical compounds and materials. In recent years, ball milling has become increasingly popular in the production of highly complex chemical structures. In such synthesis, steel balls are shaken with the reactants and catalysts in a rapidly vibrating jar. Chemical transformations take place at the sites of ball collision, where impact causes instant "hot spots" of localized heat and pressure. This is difficult to model and, without access to real time reaction monitoring, mechanochemistry remained poorly understood. "When we set out to study these reactions, the challenge was to observe the entire reaction without disturbing it, in particular the short-lived intermediates that appear and disappear under continuous impact in less than a minute", says Tomislav Friščić, a Professor at McGill University in Montreal.
The team of scientists chose to study mechanochemical production of the metal-organic framework ZIF-8 (sold as Basolite Z1200) from the simplest and non-toxic components. Materials such as ZIF-8 are rapidly gaining popularity for capturing large amounts of CO2 and, if manufactured cheaply and sustainably, could become widely used for carbon capture, catalysis and even hydrogen storage. "The team came to the ESRF because of our high-energy X-rays capable of penetrating 3 mm thick walls of a rapidly moving reaction jar made of steel, aluminium or plastic.
The X-ray beam must get inside the jar to probe the mechanochemical formation of ZIF-8, and then out again to detect the changes as they happened", says Simon Kimber, a scientist at the European Synchrotron Radiation Facility (ESRF) in Grenoble, who is a member of the team. This unprecedented methodology enabled the real-time observation of reaction kinetics, reaction intermediates and the development of their respective nanoparticles.
This technique is not limited to ZIF-8. In principle, all types of chemical reactions in a ball mill can now be studied and optimized for industrial processing. 'These results hold promise for improving the fundamental understanding of processes central to pharmaceutical, metallurgical, cement and mineral industries and should enable a more efficient use of energy, reduction in solvent and optimize the use of often expensive catalysts. This translates into good news for the environment, the industry and the consumers who will have to pay less", concludes Tomislav Friščić.
Claus Habfast | EurekAlert!
Colorectal cancer risk factors decrypted
13.07.2018 | Max-Planck-Institut für Stoffwechselforschung
Algae Have Land Genes
13.07.2018 | Julius-Maximilians-Universität Würzburg
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
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13.07.2018 | Materials Sciences
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Gas Properties and Air MCQs Quiz Worksheet PDF Download
Practice gas properties and air MCQs, science test for online course learning and test prep. Air and atmosphere quiz questions has multiple choice questions (MCQ), gas properties and air test to learn.
Science practice test MCQ on on cooling, a liquid will be changed into with options dense, solid, semi-solid and liquid problem solving skills for competitive exam, viva prep, interview questions with answer key. Free science revision notes to learn gas properties and air quiz with MCQs to find questions answers based online learning tests.
MCQs on Gas Properties and Air Quiz PDF Download
MCQ. On cooling, a liquid will be changed into
MCQ. Combustion cannot take place without
MCQ. The condensation point of oxygen gas is
MCQ. Ammonia is used to make compounds such as
- ammonium sulfate
- ammonium nitrate
- all of these
- nitric acid
MCQ. When a gas is cooled or compressed it becomes a | <urn:uuid:d2f26f3c-76f5-46fc-b042-103726b24214> | 3.59375 | 222 | Product Page | Science & Tech. | 58.187488 | 95,486,311 |
Wigner rotations and little groups
Wigner’s little groups are the subgroups of the Poincaré group whose transformations leave the four-momentum of a given particle invariant. For a relativistic particle in motion the little group is a boosted rotation. On the other hand, the kinematical effect of two non-colinear Lorentz boosts is another boost preceded or follwed by a rotation, which is called the Wigner rotation. It is shown that there is always a Wigner rotation for a given little group rotation. The differences between those two rotations are clearly demonstrated and some interesting physical applications are presented.
KeywordsWigner’s little groups Wigner rotations
PACS42.55.Ah 11.30.Cp 42.15.Eq
- 7.S. Ba§kal and Y.S. Kim, math-ph/0210056, to appear in Phys. Rev. E 67 (2003).Google Scholar | <urn:uuid:41ca9b58-eeb8-43bb-bc87-015e6b9c2b93> | 2.5625 | 213 | Academic Writing | Science & Tech. | 64.801405 | 95,486,331 |
Antoine Lavoisier recognized and named hydrogen. Lavoisier helped construct the metric system, wrote the first extensive list of elements, and helped to reform chemical nomenclature.
A German scientist called Johann Dobereiner put forward his law of triads. Each of Dobereiner's triads was a group of three elements. The appearance and reactions of the elements in a triad were similar to each other.
Julius Lothar Meyer had produced a table of just 28 elements which he listed by their valence. The 28 elements were almost entirely main group elements. He incorporated transition metals in another table in 1868 which listed the elements in increasing weight order with elements with the same valence in a given column. This was earlier than Mendeleev's table but unfortunately Meyer's was not published until 1870.
John Newlands put forward his law of octaves. He arranged all the elements known at the time into a table in order of relative atomic mass. When he did this, he found that each element was similar to the element eight places further on.
Russian chemist called Dmitri Mendeleev published a periodic table. Mendeleev also arranged the elements known at the time in order of relative atomic mass, but he did some other things that made his table much more successful.
Ramsay’s curiosity was piqued by Lord Rayleigh’s observation that the density of nitrogen extracted from the air was always greater than nitrogen released from various chemical compounds. Ramsay then set about looking for an unknown gas in air of greater density, which—when he found it—he named argon. While investigating for the presence of argon in a uranium-bearing mineral, he instead discovered helium. This second discovery led him to suggest the existence of a new group of elements in the periodic table. He and his coworkers quickly isolated neon, krypton, and xenon from the earth’s atmosphere.
J. J. Thomson set out to prove that the cathode rays produced from the cathode were actually a stream of negatively charged particles called electrons. From Maxwell's theory, he knew that charged particles could be deflected in a magnetic field.
Niels Bohr was the first to discover that electrons travel in separate orbits around the nucleus and that the number of electrons in the outer orbit determines the properties of an element.
A. van den Broek suggested that it was a mistake to compare the charge on the nucleus with the atomic weight of the element. He suggested that the charge should be compared with the atomic number, which specifies the position of the element in the periodic table. Within experimental error, the estimate of the charge on the nucleus obtained from a-particle scattering experiments is equal to the atomic number of the element.
Using atomic number instead of atomic mass as the organising principle was first proposed by the British chemist Henry Moseley in, and it solved anomalies like this one. Iodine has a higher atomic number than tellurium | <urn:uuid:5882a457-ff43-4f98-b28b-b011af6a1888> | 4 | 609 | Knowledge Article | Science & Tech. | 42.107258 | 95,486,337 |
"A portable high speed drill is driven by a small turbine which uses air drawn from a high pressure air bottle of volume 0.01m^3. The bottle is rigid and heat transfer in both bottle and turbine may be neglected.
The initial bottle pressure is 100bar, and air is used until the pressure falls to 50 bar. During the process the air in the bottle obeys pv^1.4 = constant. The initial temperature was 300k. The air leaves the turbine at a constant temperature of 120K and with negligible velocity."
I can do part a) what is final temp of bottle (=246K)
but part b) What is the work supplied by the turbine to the drill?
Please could someone show me how to get to the final answer of 70.4kJ.
(Assuming Cp for air = 1.005 KJ/KgK, cp/cv = 1.4)
Turn on thread page Beta
Thermodynamics Question, watch
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02-05-2012, 06:33 AM
EC1253 Electromagnetic Fields
This are only Important Questions obtained from Previous year Question Paper, these Question may or may not come in Exam, Vidyarthiplus doesn't take any responsibility in it.
1.Derive the expression for electric Field on the axis at a point h m of a uniformly charged
circular disc of radius a m with a charge density of ρs c/m2
2. Find the electric field intensity of a straight uniformly charged wire of length ‘L’m
and having a linear charge density of +ρ C/m at any point at a distance of ‘h’ m
3. State and Prove Gauss’s law. List the limitations of Gauss’s law.
4. Find the magnetic field density at appoint on the axis of a circular loop of a radius b that carries a current I
5 Explain coulomb’s Law .three equal positive charges of 4X 10-9 coulomb each are located at three corners of a square ,side 20cm.determine the electric field intensity at the vacant corner point of the square.
1.Circular disc of radius ‘a’ is uniformly charged with a charge density of s c/m2. Find the electric field intensity at a point ‘h’ from the disc along its central axis
2. Derive an expression for magnetic field strength, H, due to a current carrying conductor of finite length placed along the y- axis, at a point P in x-z plane and ‘r’ distant from the origin.
3. Derive the expression for the E at a point P due to an electric dipole.
4. Find the magnetic field intensity at the centre O of a square loop of sides equal to 5M and carrying 10A of current
1.Solve the laplace’s equation for the potential field in the hompogenous region between the two concentric conducting spheres with radius ‘a’ and ‘b’ where b>a V=0 at r = b and V =V0 at r=a .find the capacitance between the two concentric spheres.
2.Determine the inductance of a solenoid of 2500 turns wound uniformly over a length of 0.25m on a cylindrical paper tube , 4 cm in diameter .the medium is air
3. A cylindrical capacitor consists of an inner conductor of radius a and an outer conductor of radius b. The space between the conductors filled with a dielectric whose permittivity ε, the length of the capacitor is L. Determine the capacitance
4.Derive an expression for the inductance of solenoid
5.Show that the inductance of the cable L = µl/2π (ln b/a) H.
6.Derive an expression for the capacitance of a spherical capacitor with conducting shells of radius a and b.
1.Solve one dimensional Laplace’s equation to obtain the field inside a parallel plate capacitor and also find the surface charge density at two plates
2.State and prove Poynting theorem.
3.Derive Maxwell’s equation derived from Faraday’s law both in Integral and point forms
4. Three capacitors of 10,25 and 50 microfarads are connected in series and parallel. Find the equivalent capacitance and energy stored in each case ,when the combination is connected across a 500 V supply
5.Derive modified form of Ampere’s circuital law in Integral and differential forms
1.Derive the expression for the reflection by a perfect dielectric –normal incidence
2.Obtain the wave equation for a conducting medium
3.Derive the wave equation starting form Maxwell’s equation for free space For good dielectrics derive the expressions for α, β, ν and η.
4. Find α, β, ν and η. for Ferrite at 10GHz εr = 9, μr = 4, σ = 10 ms/m
For the student , by the student , to the student !!
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See https://play.golang.org/p/u4E6mrios0 for the completed code from this video.
In this video we learn how to represent a binary tree in Go code. Once we have the basic structure in place, we then go a step further and define an input file format that we can use to read in arbitrary binary trees moving forward to test our algorithms with.
This post is part of the Let's Learn Algorithms series where we learn how algorithms work, see how to implement them, and then spend some time working on practice problems to reinforce how the implementation details work, as well as to help you learn to recognize problems that could be solved using any particular algorithm.
The series is inspired by feedback on reddit and based on my personal experience with teachers and programming team coaches that I had the pleasure of working with at UCF. If you have any feedback, feel free to reach out - firstname.lastname@example.org.
You can view all of the videos in the Let's Learn Algorithms Graph Theory subsection to see if there is one covering a particular topic you are interested in. You can also check out the transcripts for the video below.
The transcripts below are generated automatically. They aren’t that good and have many errors, but hopefully they help a little bit. If you want you can send corrections for any timestamp.
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27. Correct. The answer is true. To find the optimal point set the first derivative of f'(x) = 0, or f'(x) = -4x + 4 = 0. From this x0 = 1. To determine whether the optimal point is a relative/global maximum of minimum or neither, check the sign of the second derivative evaluated at the optimal point: f"(x) = -4 for all values of x, therefore, x0 is a global maximum. | <urn:uuid:a600f61f-5153-4500-8d97-53427aca1032> | 2.765625 | 101 | Tutorial | Science & Tech. | 81.387619 | 95,486,426 |
Scientists Refute IPCC’s Latest Alarmism On Global Warming
The latest United Nations climate report is sounding the alarm on man-made global warming, saying that fossil fuels needed to be eliminated from the energy supply in the coming decades to avoid catastrophe.
“Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems,” reads the UN Intergovernmental Panel on Climate Change’s latest report.
“Decarbonizing… electricity generation is a key component of cost-effective mitigation strategies in achieving low stabilization levels,” the IPCC noted, adding that green energy needed to make up 80 percent of the world’s energy supply by 2050 and 90 percent by 2100 in order to kep temperatures from rising 2 degrees Celsius above pre-industrial times.
Despite the stark warning from the IPCC, some scientists have said the warning is not dire enough. The Washington Post’s Chris Mooney reported last week about scientists who thought the IPCC’s global warming predictions were too cautious. These scientists argue that the IPCC process can “lead to downplaying the full ranges of future scenarios.”
But while some scientists are saying the IPCC isn’t alarmist enough in its reporting on global warming, others argue that the UN climate bureaucracy is too alarmist in its predictions.
“The IPCC should be lowering their estimates of future impacts, most definitely not raising them,” Cato Institute scientist Chip Knappenberger told The Daily Caller News Foundation. “There is a major flaw in the IPCC [fifth assessment] (and all previous reports as well) in that the climate models that are used to produce all the scary climate projections are very likely, collectively, too sensitive to the buildup of atmospheric carbon dioxide.”
Knappenberger is referring to a measurement called “climate sensitivity” — referring to the estimated temperature rise from a doubling of atmospheric concentrations of carbon dioxide levels. Increasingly, scientists have been lowering their climate sensitivity measures as temperatures refuse to increase in two decades.
“Only desperate climate alarmists would have the gall to suggest the IPCC produces ‘conservative’ estimates of climate change in light of a growing mountain of evidence that the IPCC actually exaggerates potential climate change,” echoed Pat Michaels, director of Cato’s Center for the Study of Science.
Satellite temperature data shows average global temperatures have not displayed a warming trend in more than 18 years. This so-called pause in global warming has baffled scientists, who have offered dozens of explanations for why global temperatures have not trended upwards in nearly two decades.
“Sometimes, the smartest thing a forecaster can do is look out the window,” Michaels said. “Obviously, way too much warming has been and is being predicted.”
The IPCC has actually overestimated warming since 1950, according to Michaels. “It turns out that the average warming trend predicted for every period of record [1950-2013, 1951-2013, 1952 and others] are greater than what has been observed,” he said.
Scientists and environmentalists, however, have fired back at claims that climate models are running too hot by noting that surface temperature records show the last three decades have been hotter than any other on record. In fact, scientists predict 2014 is on track to be the hottest year on record globally.
Knappenberger noted, however, that even if 2014 is the hottest year on record, the observe average global temperature has been well below what climate models predicted.
Knappenberger wrote that “global warming fear-mongers point out that the average global temperature so far this year is a few hundredths of a degree higher than the previous record. Yet they fail to point out that the same temperature is more than two-tenths of a degree (about 10 times as much) below where it was supposed to be based on computer model projections of climate change resulting from the increase in greenhouse gases in the atmosphere.”
“They throw out statistics like ‘the 12 hottest years on record have come in the past 15 years.’ And yet never mention the fact that 15 of the past 15 years are cooler than their (obviously overheated) global warming predictions,” Knappenberger added.
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Although compressed natural gas represents a cleaner and more efficient fuel for vehicles, its volatile nature requires a reinforced, heavy tank that stores the gas at high pressure and therefore limits vehicle design. Researchers at the University of Pittsburgh's Swanson School of Engineering are utilizing metal-organic frameworks (MOFs) to develop a new type of storage system that would adsorb the gas like a sponge and allow for more energy-efficient storage and use.
The research, "Mechanisms of Heat Transfer in Porous Crystals Containing Adsorbed Gases: Applications to Metal-Organic Frameworks," was published this week in the journal Physical Review Letters by Christopher E. Wilmer, assistant professor of chemical and petroleum engineering, and postdoctoral fellow Hasan Babaei.
Traditional CNG tanks are empty structures that require the gas to be stored at high pressure, which affects design and the weight of the vehicle. Dr. Wilmer and his lab are instead focused on porous crystal/gas systems, specifically MOFs, which possess structures with extremely high surface areas.
"One of the biggest challenges in developing an adsorbed natural gas (ANG) storage system is that the process generates significant heat which limits how quickly the tank can be filled," Dr. Wilmer said. "Unfortunately, not a lot is known about how to make adsorbents dissipate heat quickly. This study illuminates some of the fundamental mechanisms involved."
According to Dr. Wilmer, gases have a $500 billion impact on the global economy, but storing, separating, and transporting gas requires energy-intensive compression. His research into MOFs is an extension of his start-up company, NuMat Technologies, which develops MOF-based solutions for the gas storage industry.
"By gaining a better understanding of heat transfer mechanisms at the atomic scale in porous materials, we could develop a more efficient material that would be thermally conductive rather than thermally insulating," he explained. "Beyond natural gas, these insights could help us design better hydrogen gas storage systems as well. Any industrial process where a gas interacts with a porous material, where heat is an important factor, could potentially benefit from this research."
Explore further: Chemists find better way to pack natural gas into fuel tanks
Physical Review Letters, journals.aps.org/prl/abstract/ … ysRevLett.116.025902 | <urn:uuid:d0417491-f8a0-494a-9200-4055dc20ca94> | 3.359375 | 485 | News Article | Science & Tech. | 30.269964 | 95,486,437 |
If electrons do not have a fixed position, that means we don't either?
Science cannot fix a position on electrons that run around the nucleus. They seem to pop in and out of existance. As we are all made of atoms and electrons do we also pop in and out of existance?
We cannot tell where an electron is exactly. They orbit around the atom but the orbital radius is not definite. However, you are able to determine where they are most likely to appear with the help of Schrodinger's equation.
Even so, the exact position of other particles, such as protons and neutrons can be determined. Since our body is made up of more than just electrons, it is possible to determined their position.
If you want to dig deeper, we can talk about relativity which brings up the question on which frame of reference we are comparing with. Different reference frame will describe the object differently; whether it is the position, shape, direction of motion, etc.
I am not so sure about matter popping in and out of existence but I do know that if you transport matter at an impossibly high speed, you can convert matter into waves such as radio waves and light. This is one way you can make matter disappear. Or you could try converting it into energy which according to Einstein's equation, is possible.
Harmonic nodes of vibration - warped space-time, 26 dimensions from super-string theory - and no unified theory of everything - might as well try to speak the ineffable name of God - our mammel brains can not imagine without symbols of the macro world.
quantum physics theories are so hard to understand because the equations are "particles" when they really are tensors - there is no electron at rest - it exists only in motion.
by Sundeep Kataria 4 years ago
Is everything predestined? Then why go out of the way to change things?
by Dennis L. Page 5 years ago
What does "Stand By Me" mean to you?Many have heard the song "Stand By Me," but what does this phrase mean to you on a personal level? My wife is a school teacher and she is doing a lesson on this subject and in follow up, I would like to know how we, as adults, feel about this?
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A COATING that allows the first ever continuous production of cells could remove a significant bottleneck in the production of cell-based therapies, according to researchers.
The team, from the University of Newcastle, UK, says their surface coating removes the limit on the number of cells that can be grown in a culture dish, which until now has been strictly confined by its surface area. This would save costs, reduce materials and improve the quality of products to treat heart, cartilage, skin and cancer-related diseases.
While current methods of production require batch culture, where cells are chemically or enzymatically removed all at once after growth, the new coating allows cells to continuously self-detach for collection. As a result, further cells can grow in their place.
“This allows us to move away, for the first time, from the batch production of cells to an unremitting process,” said Che Connon, professor of tissue engineering at Newcastle, adding: “With our new technology, 1 m2 would produce enough cells to treat 4,000 patients, while traditional methods would require an area equivalent to a football pitch.”
The coating is made from peptide amphiphiles, which are molecules based on small chains of amino acids. This class of materials combines the structural features of amphiphilic surfactants with the functions of bioactive peptides, and are known to assemble into a variety of nanostructures.
The team’s coating works by providing a cell binding site above an amino acid sequence that is sensitive to a class of enzymes called matrix metalloproteinases (MMPs). Cells to be grown produce MMPs as they grow, which facilitates their release. The rate of cell detachment can be controlled by adding retinoic acid, which changes the rate at which cells produce MMPs.
In a ACS Applied Materials & Interfaces paper, use of the coating was demonstrated to result in a ~1% recovery of the total attached cells per hour, which was maintained over a month.
“Our new technology also offers complete control over the rate of cell production, so it could be scaled up using existing stacked culture flasks to produce 1bn cells per week, or scaled down so as to fit a bioreactor on the head of a pin,” Connon said.
While continuous, bioprocessing is currently used to produce biopharmaceuticals like vaccines and anti-cancer antibodies, it has never been achieved for cellular therapies. Such treatments, which include stem cell therapies, can require up to a billion cells per patient – and there are, for example, an estimated 10m annual patients who could benefit from cardiac cell therapy.
Connon told The Chemical Engineer that the main challenge now facing the development of his technology is its radical nature. “Systems have been set up for batch culture for the last 50 years,” he said, adding: “We are now looking for commercial partners to co-develop this technology. This could be in cell-therapy or any business requiring lots of cells – for example, Memphis Meats (a food technology company growing cultured meat) could be an interesting partner.”
ACS Applied Materials & Interfaces: http://doi.org/cgfv | <urn:uuid:3154e092-1c18-402f-b208-1eae6c70abfa> | 3.390625 | 674 | News Article | Science & Tech. | 33.116146 | 95,486,474 |
Global mean sea level rise is accelerating faster than previously thought
Globally sea levels are on the rise. Now researchers from TU Delft and other European universities report a reconstruction of global mean sea level since 1902 that yields a slower average rise before 1990 than previously thought, but shows similar high rates as independent satellite observations from 1993-2012. This suggests that global mean sea level has been accelerating much faster than previously assumed in the past two decades. The results appear this week in the Proceedings of the National Academy of Sciences (PNAS).
While altimeters on board of satellites are now monitoring sea levels consistently around the globe, before their launch in 1992 the only information on global mean sea level rise comes from a network of tide gauges along the coast. “These tide gauges measure sea level at specific locations relative to the ground and are therefore contaminated by vertical land motion of the Earth and regional variability patterns resulting from wind redistribution, ocean circulation changes, or gravitationally triggered mass redistribution effects after freshwater pulses from land-locked water. This makes it very complicated to estimate a global average, which is not contaminated by local features from better covered regions”, says first author dr. Sönke Dangendorf of the University of Siegen, Germany.
Dangendorf and his colleagues took a closer look at available tide gauge records and ancillary information of potential contamination factors. “We selected only the longest and high quality tide gauges, which best cover certain regions of the global ocean. Then, we corrected each of these tide gauges for all potential contamination factors before averaging them into a global mean”, explains dr. Marta Marcos, of the University of the Balearic Islands at Mallorca.
Researchers from TU Delft - ir. Thomas Frederikse and dr. Riccardo Riva - looked into a specific factor in sea level rise. ‘The global ice mass loss also has an effect on the distribution of mass on Earth. This results in a slight change in gravitational forces and the rotation (speed and angle) of the Earth’ , says Riva. ‘This in turn has an effect on sea levels, with very large regional differences. The mean effect turns out to lead to only a relatively small correction globally, but of course you have to take it into account to get a complete picture.’
After applying all the different corrections, the new reconstruction shows significantly slower global mean sea level rise before 1993, while afterwards the reconstruction goes in concert with the independent observational record from satellites. “The most sensitive factor was the vertical land motion correction”, professor Guy Wöppelmann from the University of La Rochelle, France, adds. “While former reconstructions could only correct for one particular process of vertical land motion, namely glacial isostatic adjustment, we were now able to add other local effects”, Guy Wöppelmann further explains. In most regions these contributions have, together with some methodological adjustments, resulted in a significant downward correction of relative sea level rates before 1990 (1.1 mm/yr).
As a result of this downward correction before 1990, the entire shape of the global mean sea level curve changed significantly. Due to the flatter character at the beginning and the unaltered high rates during the last two to three decades the 20th century acceleration becomes more pronounced. “Such acceleration is now more consistent with our understanding of individual processes contributing to the observed sea level rise.
Article #16-16007: “Reassessment of 20th century global mean sea-level rise,” by Sönke Dangendorf, Marta Marcos, Guy Wöppelmann, Clint Conrad, Thomas Frederikse, and Riccardo Riva.
Contact Riccardo Riva: www.tudelft.nl/staff/r.e.m.riva/ Science Information Officer TU Delft Roy Meijer, email@example.com, +31 15 278175 | <urn:uuid:ccfa168e-3495-49a0-9f14-c4756962afea> | 3.296875 | 832 | News (Org.) | Science & Tech. | 32.017991 | 95,486,475 |
Water can be tricky. With too little, crops die, industries move away, power plants fail, ecosystems suffer and people go thirsty. With too much, floods ruin infrastructure, destroy crops, spread waterborne diseases, and disrupt flows of clean water, wastewater, power and transportation. We want water at the right time and in the right place because moving and storing water require effort. We also want it at the right quality and the right temperature. Saline water, brackish water and polluted water are abundant but costly to treat. Water that’s too warm won’t cool power plants effectively and can damage ecosystems, while water that’s too cold can burst pipes and damage infrastructure.
Water’s capriciousness, however, can be tempered – with energy. If we had unlimited and perfectly clean energy (to mitigate environmental impacts) at our disposal, we could desalinate the ocean, providing enough potable water for everyone, everywhere. We could build pipelines to move water from where it is abundant to where it is scarce. We could build adequate sanitation infrastructure in communities that lack it so that raw sewage does not flow into freshwater ecosystems and cause sickness and eutrophication. We could build more storage reservoirs so that water could be collected in times of excess to be used in times of shortage.
Of course, we do not have unlimited energy and what we do have isn’t perfectly clean, and consequently, energy has become a constraining factor on our management of water issues.
The corollary is also true: Just as energy constraints become water constraints, in many regions, water has become a constraining factor on the energy supply. Power plant operators sometimes don’t have access to enough water to build new power generation facilities using conventional designs. And they face environmental constraints on the temperature of cooling water that is discharged into local streams based on limits established to protect fish and ecosystems. Water can also be a constraining factor in extracting energy sources such as in oil and gas production, which can use tremendous amounts of water.
This interdependence between water and energy is called the energy-water nexus. And while the relationship can be mutually constraining, it also presents an opportunity to address both energy and water issues together, because conserving one leads to conservation of the other. Consequently, the way we manage the delicate relationship between the two will have major implications on the future of our energy and water crises.
Before the advent of centralized water and mechanical pumping systems, people typically drew water from their local stream, river or well, even in urban areas. The only energy involved was that expended to draw and carry the water. In many rural or poor parts of the world, this is still the case. Breaking from that tradition, the U.S. began developing its centralized drinking water treatment and distribution systems in the early 1900s and now enjoys one of the safest and most abundant public water supplies in the world.
Due to increasing demand, current trends in the United States’ water sector suggest that we are moving toward the use of more energy-intensive water: for example, water that has been desalinated in places like Southern California and Florida; or that has been extracted from deep aquifers as in the Colorado Rockies and Great Plains; or that has been transferred between basins, which is done in the Desert Southwest and California.
These trends raise questions about how much energy we use to treat, move and prepare water for end use today, and what lessons learned from the United States’ water system can be applied to other regions in the world that are still developing large centralized water systems and wastewater infrastructure.
Our recent research has examined these questions. To calculate how much energy we use for water on a national scale, we first tallied the energy used in the U.S. to pump water to treatment facilities and treat it. Then we added up water-related home energy use for purposes such as heating water for bathing and cooking. Finally, we included nonhousehold energy used for water in businesses, public facilities, industrial facilities and power plants. We found that annually the U.S. spends 12.3 quadrillion BTU (12.6 percent of our total annual energy consumption) in one way or another directly on water – much more than we had anticipated.
Energy Used for Water in the U.S.
In the U.S., that 12.3 quadrillion BTU includes uses for everything from extraction through treatment, end uses and disposal. Approximately 30 percent of that energy is consumed exclusively for residential and commercial water heating. Another 30 percent is used to heat and pressurize water for steam-injection in industrial processes such as oil refining and chemical manufacturing. Appliances such as dishwashers, washing machines and dryers, which heat water to clean and heat air to dry, represent about 8 percent of water-related energy use.
Although water treatment is envisioned as the poster child of energy spent on water, water treatment uses a relatively small amount of energy compared to that consumed at the point of use. Energy consumed for water treatment by public water utilities represents only 4 percent of the 12.3 quadrillion BTU (equating to 0.5 percent of total 2010 U.S. energy consumption). The remaining 28 percent is spread across multiple uses.
The energy required for water treatment is dictated by the water quality of the source and specific end use. Groundwater typically requires more energy for pumping than surface water, and those energy requirements increase with well depth. But surface water, which is sometimes degraded from runoff or industrial discharge, often requires more treatment than large groundwater sources, which tend to be cleaner. Once treated, the water is pumped from the treatment facility through the water distribution system to its final end user, where it might be heated, pressurized, pumped or cooled.
Approximately 40 percent of the water that leaves a water treatment plant is returned to the environment through outdoor irrigation or leaks (although this proportion varies a great deal by location and season). Water that is used inside and flushed down the drain (or the toilet) is delivered to a wastewater treatment facility and reconditioned to a cleanliness level that is appropriate for release into the environment. A small fraction of the reconditioned water might be “reclaimed” for nonpotable purposes such as irrigating golf courses or for power plant cooling.
Thermoelectric power producers, agricultural users and many industrial facilities typically extract their own water, as opposed to receiving it from the public water supply. For some activities, raw water quality is sufficient and does not require additional treatment. For other applications, onsite water treatment might be required. Contaminated wastewater from self-supplied water users is still required to be treated to a standard consistent with the EPA’s Clean Water Act before being discharged to the environment.
Regional Challenges, Regional Solutions
Despite these broad characterizations and averages regarding national water-related energy use, the United States is a difficult place to generalize. Disparate climates with varying amounts of precipitation and susceptibility to drought affect the availability of surface water and groundwater, which affects pumping depths and distances. Homeowners in Southern California, for example, are likely to receive water that has been pumped hundreds of kilometers, through two mountain ranges, from the San Joaquin Delta in Northern California. Before the water even reaches its intended customers, it has an energy intensity of about 11 kilowatt-hours (kWh) per 1,000 gallons (though some of that is recovered with in-line turbines as the water flows within pipes back down from the mountain passes). By contrast, customers in Massachusetts, where precipitation and water reservoirs are ample, receive water that has an intensity of about 1.5 kWh per 1,000 gallons, a mere 14 percent of their California counterparts. (However, even in Southern California, end-use activities such as water heating, cooling, pumping and pressurization at the point-of-use still represent nearly 60 percent of the total energy embedded in water over its entire lifecycle.)
The energy consumed by public water and wastewater utilities may currently represent a small slice of water-related energy, but many public water systems around the country are shifting toward more energy-intensive water sources that will likely increase their overall energy use in the future. States like California, Florida and Texas have built desalination facilities that, on average, require about 10 times more energy per unit of water treated than standard surface water treatment operations. Plans for long-distance pipelines to bring water to the drought-stricken West are under way, and although they might temporarily placate water shortages, they have high energetic and financial costs.
In the meantime, droughts in the West, Great Plains and Midwest have increased pressure on over-pumped aquifers, causing water tables to fall and forcing users to draw up from deeper water levels.
Historically, cities and communities grew around available water sources, with the assumption that those sources would last indefinitely. But with new demands on water resources, this planning assumption is challenged. As the water moves to new locations, one question that looms is whether we will move the people to be close to the water or move the water to be close to the people.
There are some bright spots in the United States’ water picture. Reclaimed wastewater is being used for purposes such as landscape and golf course irrigation, power plant and industrial cooling, and toilet flushing. It is also being used to replenish aquifers: In Orange County, Calif., falling aquifers have become increasingly susceptible to saltwater intrusion. In response, scientists and engineers designed a system to reinject treated wastewater into the depleted aquifers to create a barrier to keep saltwater from contaminating valuable freshwater resources.
Water conservation has also led to important reductions in demand. Water-efficient cooling technologies for power plants reduce their water demand. Many industries have reduced the water-intensity of their supply chains to decrease vulnerability to water shortages. More efficient irrigation systems, low-flow appliances, and xeriscaping – landscaping with native plants that do not require irrigation – also offer water savings for municipalities. Significant savings in irrigation remain for the agricultural sector.
Follow the Leader?
Like the U.S., other countries are moving toward more energy-intensive water via large infrastructure projects intended to deliver clean water from water-rich regions to water-scarce regions. In China, the South-North Water Transfer Project, slated for completion in 2050, includes plans for three water pipelines of 500, 1,200 and 1,300 kilometers in length, respectively. Egypt, India, Libya and South Africa, as well as other developing and developed countries, are planning or constructing very large water-supply projects. Similarly, countries such as India, Kuwait, Saudi Arabia, Singapore and the United Arab Emirates have already committed to large desalination facilities to increase potable water supplies. But these projects are very costly and markedly increase the energy consumed to bring water to people around the world.
There is a delicate balance between energy and water resources. Large water infrastructure projects bring water to people who might not otherwise have it, but they also stress the energy infrastructure and impact efforts to move toward alternative sources. However, conservation, reclaimed water projects, and desalination powered with renewable energy could achieve energy, water and climate objectives, simultaneously. For example, Saudi Arabia is building the first commercial-scale solar-powered seawater reverse osmosis desalination plant in the world. Once construction is completed later this year, the plant is anticipated to meet the daily water needs of 100,000 people. In the Desert Southwest of the U.S., something similar could be done to turn the vast brackish water resources into freshwater using renewable wind or solar resources.
How the U.S. and other water-constrained countries manage water during the transition from nonrenewable to sustainable sources of energy poses one of the biggest ongoing challenges of the 21st century.
Kelly T. Sanders and Michael E. Webber
Sanders is a National Science Foundation Graduate Research Fellow and Ph.D. student in civil engineering at the University of Texas at Austin. She will be joining the faculty of the Sonny Astani Department of Civil and Environmental Engineering at the University of Southern California in 2014. Webber is the Josey Centennial Fellow in Energy Resources and Deputy Director of the Energy Institute at the University of Texas at Austin. | <urn:uuid:cfe37a25-d60c-45d0-9f3d-8cdbbeb0144a> | 3.6875 | 2,542 | Nonfiction Writing | Science & Tech. | 29.92993 | 95,486,498 |
Basically, air pollution may be defined as “any atmospheric condition in which substances are present at concentrations high enough above their normal ambient levels to produce a measurable effect on man, animals, vegetation or materials, with substances meaning any natural or man-made chemical elements or compounds capable of being airborne, which may exist in the atmosphere as gases, liquid drops or solid particles” (Seinfeld 1986). Whereas in the past decades atmospheric pollution could be considered as a local and temporal limited phenomenon characteristic of large urban centres and industrial regions, in recent years the principal pollution of the Earth’s atmosphere has become a matter of world-wide concern and dramatically increasing ecological and political importance.
KeywordsStratospheric Ozone Methyl Chloride Fire Extinguisher Ozone Molecule Atmospheric Lifetime
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- Fabian P (1986) Halogenated hydrocarbons in the atmosphere. In: Hutzinger O (ed) Air pollution. Springer, Berlin Heidelberg New YorkGoogle Scholar
- Finlayson-Pitts BJ, Pitts JN (1986) Atmospheric chemistry, Wiley, New YorkGoogle Scholar
- Graedel TE, Hawkins DT, Claxton LD (1986) Atmospheric chemical compounds. Academic Press, New YorkGoogle Scholar
- Holdgate MW (1979) A perspective of environmental pollution. Cambridge University Press, CambridgeGoogle Scholar
- National Research Council (1984) Causes and effects in stratospheric ozone: update, 1983. National Academy Press, Washington, DCGoogle Scholar
- NATO Advanced Study Institute on Atmospheric Ozone (1980) Report FAA-EE-80–20, US Dept of Transportation, Washington, DCGoogle Scholar
- 13.Royal Commission on Environmental Pollution (1984) 10th report. LondonGoogle Scholar
- Seinfeld JH (1986) Atmospheric chemistry and physics of air pollution. Wiley, New YorkGoogle Scholar
- Wayne RP (1985) Chemistry of the atmospheres. Clarendon Press, OxfordGoogle Scholar
- WNO (1981) Report 11: The stratosphere 1981: theory and measurements. WNO, GenevaGoogle Scholar | <urn:uuid:d074462b-2b8f-4d32-be74-aa446430ad4d> | 2.890625 | 496 | Academic Writing | Science & Tech. | 17.519052 | 95,486,505 |
Overhead comparison of cloned pigs shows hair growth pattern variation#
© NC State University
New research at North Carolina State University’s College of Veterinary Medicine indicates that cloned pigs can have the same degree of variability in physical appearance and behavior as normally bred animals. Two separate studies show that while clones are genetically identical to the original animal, the similarities end there.
This dispels the commonly held notion that cloned animals retain the physical and behavioral attributes of the animal from which they were cloned. The research was conducted by Dr. Jorge
Piedrahita, professor of molecular biomedical sciences at NC State, and colleagues at Texas A&M University. His study on cloned pig behavior, which appears in Applied Animal Behaviour Science, is the first published research on the behavior of cloned mammals. The study on cloned pig physiology, which appears in Biology of Reproduction, is the first study on clone physiology that included control subjects.
Greg Thomas, | NC State University
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
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Tiny particles known as neutrinos are an excellent tool to study the inner workings of atomic nuclei. Unlike electrons or protons, neutrinos have no electric charge, and they interact with an atom’s core only via the weak nuclear force. This makes them a unique tool for probing the building blocks of matter. But the challenge is that neutrinos are hard to produce and detect, and it is very difficult to determine the energy that a neutrino has when it hits an atom.
This week a group of scientists working on the MiniBooNE experiment at the Department of Energy’s Fermilab reported a breakthrough: They were able to identify exactly-known-energy muon neutrinos hitting the atoms at the heart of their particle detector. The result eliminates a major source of uncertainty when testing theoretical models of neutrino interactions and neutrino oscillations.
“The issue of neutrino energy is so important,” said Joshua Spitz, assistant professor at the University of Michigan and co-leader of the team that made the discovery, along with Joseph Grange at Argonne National Laboratory. “It is extraordinarily rare to know the energy of a neutrino and how much energy it transfers to the target atom. For neutrino-based studies of nuclei, this is the first time it has been achieved.”
This interior view of the MiniBooNE detector tank shows the array of photodetectors used to pick up the light particles that are created when a neutrino interacts with a nucleus inside the tank.
Credit: Photo: Reidar Hahn
To learn more about nuclei, physicists shoot particles at atoms and measure how they collide and scatter. If the energy of a particle is sufficiently large, a nucleus hit by the particle can break apart and reveal information about the subatomic forces that bind the nucleus together.
But to get the most accurate measurements, scientists need to know the exact energy of the particle breaking up the atom. That, however, is almost never possible when doing experiments with neutrinos.
Like other muon neutrino experiments, MiniBooNE uses a beam that comprises muon neutrinos with a range of energies. Since neutrinos have no electric charge, scientists have no “filter” that allows them to select neutrinos with a specific energy.
MiniBooNE scientists, however, came up with a clever way to identify the energy of a subset of the muon neutrinos hitting their detector. They realized that their experiment receives some muon neutrinos that have the exact energy of 236 million electronvolts (MeV). These neutrinos stem from the decay of kaons at rest about 86 meters from the MiniBooNE detector emerging from the aluminum core of the particle absorber of the NuMI beamline, which was built for other experiments at Fermilab.
Energetic kaons decay into muon neutrinos with a range of energies. The trick is to identify muon neutrinos that emerge from the decay of kaons at rest. Conservation of energy and momentum then require that all muon neutrinos emerging from the kaon-at-rest decay have to have exactly the energy of 236 MeV.
“It is not often in neutrino physics that you know the energy of the incoming neutrino,” said MiniBooNE co-spokesperson Richard Van De Water of Los Alamos National Laboratory. “With the first observation by MiniBooNE of monoenergetic muon neutrinos from kaon decay, we can study the charged current interactions with a known probe that enable theorists to improve their cross section models. This is important work for the future short- and long-baseline neutrino programs at Fermilab.”
This analysis was conducted with data collected from 2009 to 2011.
“The result is notable,” said Rex Tayloe, co-spokesperson of the MiniBooNE collaboration and professor of physics at Indiana University Bloomington. “We were able to extract this result because of the well-understood MiniBooNE detector and our previous careful studies of neutrino interactions over 15 years of data collection.”
Spitz and his colleagues already are working on the next monoenergetic neutrino result. A second neutrino detector located near MiniBooNE, called MicroBooNE, also receives muon neutrinos from the NuMI absorber, 102 meters away. Since MicroBooNE uses liquid-argon technology to record neutrino interactions, Spitz is optimistic that the MicroBooNE data will provide even more information.
“MicroBooNE will provide more precise measurements of this known-energy neutrino,” he said. “The results will be extremely valuable for future neutrino oscillation experiments.”
The MiniBooNE result was published in the April 6, 2018, issue of Physical Review Letters. This research was supported by the U.S. Department of Energy Office of Science.
Contacts and sources: | <urn:uuid:52f80bf7-1368-4fa7-843d-ecf78c3a7658> | 4.09375 | 1,053 | News Article | Science & Tech. | 29.807076 | 95,486,520 |
NASA's Aqua satellite passed over the eastern Pacific Ocean on Sept. 23 and the Atmospheric Infrared Sounder (AIRS) instrument captured an infrared image of Tropical Storm Miriam's cloud top temperatures. Tropical Storm Miriam is born that day, about 640 miles (1,025 km) south-southeast of the southern tip of Baja California. Cloud top temperatures are an indication of uplift in a storm.
This infrared image of Tropical Storm Miriam was captured by the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite. The image was taken on Sept. 23 at 2011 UTC and revealed that Miriam had a huge area (purple) of strong thunderstorms and heavy rainfall around the center of circulation. (Credit: NASA JPL, Ed Olsen)
Uplift is the push of air upward that allows formation of towering clouds and thunderstorms that make up a tropical cyclone. The infrared data indicated a large area of strongest thunderstorms and heaviest rainfall surrounding the center of circulation. Those cloud top temperatures exceeded -63 Fahrenheit (-52 Celsius).
On Friday, Sept. 24 at 11 a.m. EDT, Tropical Storm Miriam became an eastern Pacific hurricane with maximum sustained winds near 120 mph (195 kmh). Miriam was located about 410 miles (655 km) south-southwest of the southern tip of Baja California, Mexico, near latitude 17.7 North and longitude 112.9 West. Miriam is moving northwest near 12 mph (19 kmh) and a gradual turn to the west and southwest is expected later.
Visible imagery from NOAA's GOES-15 satellite suggests the formation of a small eye, while NASA's Tropical Rainfall Measuring Mission (TRMM) satellite data suggest that an outer eyewall is forming. The National Hurricane Center noted that barring an eyewall replacement, Miriam could strengthen even more in the next day.Text credit: Rob Gutro
Rob Gutro | EurekAlert!
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
Drones survey African wildlife
11.07.2018 | Schweizerischer Nationalfonds SNF
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
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Two small headwater lake basins that receive similar amounts of acidic atmospheric deposition have significantly different lake outflow pH values; pH at Panther Lake (neutral) ranges from about 4.7 to 7; that at Woods Lake (acidic) ranges from about 4.3 to 5. A hydrologic analysis, which included monthly water budgets, hydrograph analysis, examination of flow duration and runoff recession curves, calculation of ground-water storage, and an analysis of lateral flow capacity of the soil, indicates that differences in lakewater pH can be attributed to differences in the ground-water contribution to the lakes. A larger percentage of the water discharged from the neutral lake is derived from ground water than that from the acidic lake. Ground water has a higher pH resulting from a sufficiently long residence time for neutralizing chemical reactions to occur with the till. The difference in ground-water contribution is attributed to a more extensive distribution of thick till (<3 m) in the neutral-lake basin than in the acidic-lake basin; average thickness of till in the neutral-lake basin is 24 m whereas that in the other is 2.3 m. During the snowmelt period, as much as three months of accumulated precipitation may be released within two weeks causing the lateral flow capacity of the deeper mineral soil to be exceeded in the neutral-lake basin. This excess water moves over and through the shallow acidic soil horizons and causes the lakewater pH to decrease during snowmelt.
Weitere Kapitel dieses Buchs durch Wischen aufrufen
- Hydrogeologic Comparison of an Acidic-Lake Basin with a Neutral-Lake Basin in the West-Central Adirondack Mountains, New York
Norman E. Peters
Peter S. Murdoch
- Springer Netherlands
Fallstudie Überschwemmungskarten/© Thaut Images | Fotolia | <urn:uuid:afb9f09e-dfc1-496d-b52d-08beb83ca822> | 3.421875 | 385 | Knowledge Article | Science & Tech. | 29.277353 | 95,486,525 |
A few weeks ago, for the first time ever, a computer beat the world champion of Go, one of the most complex games known to man. This was another watershed moment in the progress of artificial intelligence.
To give you an idea how complex Go is, there are 2.082 × 10^170 possible board configurations. That is 2 with 170 zeroes after it. Chances are your brain cannot even conceive of a number that large (but a computer can). Or to give you an idea of how big of a number that is, there are only 10^80 atoms in the universe — that is, one followed by 80 zeroes.
The reason this is such a big deal is that Go is so complicated that in order to beat a top human player, a machine would have to learn how to think creatively, improvising and adapting to the situation at hand without being able to calculate every possible outcome; i.e., there has to be some serious artificial intelligence going on — like real, creative intelligence.
In case you haven’t gotten the memo on the whole “AI is going to take over the world” thing, here are the few facts you need to know.
- Computers are getting smarter.
- Computers are getting smarter at an accelerating rate — i.e., advancements that used to take 10 years now take one year. Advancements that used to take one year, now take weeks or even days.
- It is highly likely that within our lifetimes, there will be computers that are far smarter and more capable than any single human being.
- These smarter computers will then likely be able to design and improve upon technology (i.e., themselves) and create new technology that we cannot even begin to fathom.
People who understand the above points generally have one of two reactions. Either:
- They think we’re totally fucked. The computers are going to take over everything and kill/enslave us all. Or:
- This is going to bring about a technological utopia that will fix all of our silly human squabbles and we can all live happily ever after having orgies in our ultra-VR world that exists in the cloud.
As with most things, the truth is likely somewhere in the middle.
But even if shit does hit the fan, even if the robots see us as the lice ruining this planet’s pristine scalp and want to round us all up and throw us into an active volcano, even if we are inadvertently inventing the very mechanisms of our own extinction…
…I don’t care. It doesn’t matter. It doesn’t bother me. And it shouldn’t bother you, either. I will explain why in a bit. But for now, you should know that I, for one, welcome our new robot overlords.
Accelerating Growth in the Tech Industry
Technological developments compound upon themselves, causing the rate of development itself to accelerate. What that means is that the more advanced technology we create, the easier it gets to create even more advanced technology. As a result, when we look at the advancement of computing technology, we see an exponential curve — i.e., the more time that goes by, the faster the things develop.
Computing power has doubled on average every 18 months for 50 years now. In terms of raw computing power, computers now rival the abilities of mouse brains, where only a few years ago, computers couldn’t even compete with an insect brain.
To give you a more immediate example of how rapid technology has advanced, more pictures are now taken every 2 minutes than were taken in the entire 19th century.1] About 10% of the 3.5 trillion photos ever taken were taken in the past 12 months.
If we are indeed on an exponential curve when it comes to high-tech advances, then people like Jeremy Howard are probably right when he says we’re only a few years away from artificial machine intelligence that rivals, if not surpasses, our own in many domains previously thought to be uniquely human.
And to be sure, AI is creeping into more and more domains of our lives.
Only a decade ago, people were laughing at the poor performance of self-driving cars. Today, only a decade later, self-driving cars can not only finish a closed-road course, they drive on busy freeways right alongside cars driven by humans.2]
And when computers aren’t beating world champion Go players, they’re busy doing things like writing articles about sports and breaking news events, writing descriptions of images they’ve never “seen” before, and diagnosing cancer. For many of these tasks, the computers are as good if not better than humans, and for the ones they’re not, they’re learning how to do them better and better every day without the help of humans.
A few short years ago, facial recognition software was incredibly expensive and not that good at identifying people in real-world settings. It was considered super-advanced spy-level technology and really only used by a few world governments.
Now Facebook can fucking tag your friends from last weekend’s barbecue.3]
Here’s the thing about accelerating growth in computers: there will one day come a point where we build a computer that is smarter than any human on Earth. On that day, computers will usurp us as the primary problem solvers on the planet, and from there, our thoughts, decisions, and actions will slowly become obsolete. The machines will be better than us at everything, so more and more, we will do nothing useful.
This terrifies some people. They envision some sort of future like Terminator or The Matrix where machines enslave us or exterminate us.
Other people look forward to the rise of the robots with a sort of cultish fervor because they believe their problem-solving capabilities will outstrip ours so much that life will become unimaginably pleasant and problem-free. All diseases will be cured. Poverty, world hunger, war, and climate change will all be solved. We’ll have an infinite amount of leisure time, and in extreme cases, some people believe the machines will make us immortal.
The Two Possible Outcomes
Since we’re always being told to be fucking positive, let’s start with the techno-utopiasts.
There are people like Ray Kurzweil who think that technology will not only improve our lives, it will save humanity and possibly guarantee our place in the universe indefinitely. Kurzweil believes in future technology like nanobots that will repair our cells and reverse aging or remove excess fat and sugar so we can eat whatever we want. And just in case our physical bodies aren’t able to live forever, Kurzweil thinks we’ll have the ability to upload our brains into the cloud and “live” in a virtual world forever, long after our physical bodies are gone.
Others in this camp think that an artificial super intelligence would be able to answer questions that are too complex for humans to even understand and we’ll be exponentially better off for it. Also, not only would the machines invent better gadgets and widgets, they would invent exponentially more efficient ways of building gadgets and widgets, making it possible for virtually everyone on the planet to reap their benefits.
A few lines of reasoning support this idea. First, even though technology has created some new problems for humanity, like nuclear weapons and YouTube celebrities, it has, so far, clearly been a net benefit for humanity. Despite what politicians and pundits want you to believe, the average person on Earth is better off than they were just a few short years ago and it’s largely due to technology becoming better, cheaper, and more widespread. If this trend continues, we may have nothing to worry about.
Second, Kurzweil and his supporters believe that technology will have no reason to harm humanity because not only is it created by us, it is becoming more a part of us. They believe we will even reach a point where our biology and our technology are indistinguishable. If this is the case, the argument goes, any form of technology that is detrimental for humans is also detrimental to itself, and a self-destructive technology of any kind cannot persist. That is, it would quickly “die off” just as a detrimental gene mutation is quickly weeded out of the gene pool.
But techno-utopiasts are likely biased in that they don’t acknowledge that all technologies can be used for various purposes, both beneficial and destructive. They’re also likely biased in that they ignore the fact that humans move slow to adapt to new technologies and that there are always groups of people who will seek to abuse those technologies for their own selfish ends.
In the other camp, you have the techno-armageddonists. I totally just made that word up, but apparently it exists, because spell-check told me so.
What the techno-armageddonists lack in conviction (most of them just aren’t sure what to think yet), they make up in celebrity star power.4] Bill Gates, Stephen Hawking, and Elon Musk are just a few of the leading thinkers and scientists who are crapping their pants at how rapidly AI is developing and how under-prepared we are as a species for its repercussions. When Musk was asked what the most imminent threats to humanity in the near future were, he quickly said there were three: first, wide-scale nuclear war; second, climate change. Before naming a third, he went silent. When the interviewer asked him, “What is the third?” He smiled and said, “Let’s just say that I hope that the computers will decide to be nice to us.”
Hope we're not just the biological boot loader for digital superintelligence. Unfortunately, that is increasingly probable
— Elon Musk (@elonmusk) August 3, 2014
Possibly the most outspoken and respected of the techno-armageddonists is the Swedish philosopher Nick Bostrom. One thing Bostrom and others fear is runaway self-improving technology; that is, a machine that is smart enough to make itself (or new versions of itself) smarter without human intervention. If it reaches a point where it surpasses human intelligence, it’s only a very short matter of time before the law of accelerating returns kicks into overdrive and the exponential curve shoots straight up and we won’t be able to stop it. Bostrom makes a good point here: creating something that is smarter than you could be an evolutionary disaster for your species.
We run a very real risk of not being able to control an entity that is orders of magnitude more intelligent than us. Perhaps if computers get smart enough, they’ll figure out a way to domesticate us a lot like humans domesticated horses to do labor like pull plows and buggies and war chariots (or whatever the hell horses did back then). The scary part is that this might be the best scenario for us — doing work for machines that they can’t do or don’t want to do — because just as humans created new technology to replace the horse, a super intelligent self-improving machine would eventually come up with new technology to replace us. And, well, let’s just say the horse population isn’t what it used to be.
Some argue that this isn’t plausible because humans build technology with safety in mind. But name the last time a major technological breakthrough was NOT used by somebody for nefarious or destructive purposes? Oh yeah, that’s right. Never.
Why I Don’t Care What Happens and Neither Should You
So let’s assume that super-intelligent machines are created and do render humanity powerless. Let’s assume they’re not integrated into us and our brains somehow and let’s assume that people like Hawking and Musk are right: that humanity really is just a multi-millennium boot drive to digital hyper-intelligence and we have outlived our usefulness.
I’m still not worried about it.
Why? Well, to keep the bullet point train rolling, let’s take this point-by-point:
1. The machines’ understanding of good/evil will likely surpass our own. When was the last time a dog or dolphin committed genocide? When was the last time a computer decided to vaporize entire cities in the name of abstract concepts such as ‘freedom’ and ‘world peace’?
That’s right, the answer is never.
My point here is not that intelligent machines won’t want to exterminate the entire human species. My point is that as humans, we’re throwing rocks from inside a glass house here. What the fuck do we know about ethics and humane treatment of animals, the environment, and each other? What leg do we have to stand on?
That’s right: pretty much nothing. When it comes to moral questions, humanity historically flunks the test. Super-intelligent machines will likely come to understand ethics, life/death, creation/destruction on a much higher level than we ever could on our own. And this idea that they will exterminate us for the simple fact that we aren’t as productive as we used to be, or that sometimes we can be a nuisance, I think, is just projecting the worst aspects of our own psychology onto something we don’t know and can’t understand.
Right now, most of human morality is based around an obsessive preservation and promotion of each of our individual human consciousnesses. What if advanced technology renders individual human consciousness arbitrary? What if consciousness can be replicated, expanded and contracted at will? It will completely obliterate any ethical understanding we could ever have. What if removing all of these lunky, inefficient biological prisons we call bodies may actually be a far more ethical decision than letting us continue to squirm and squirt our way through 80-some-odd years of existence? What if the machines realize we’d be much happier being freed from our intellectual prisons and have our conscious perception of our own identities expanded to include all of perceivable reality? What if they think we’re just a bunch of drooling idiots and keep us occupied with incredibly good pizza and video games until we all die off by our own mortality? Who are we to know? And who are we to say?
But I will say this: they will be far better informed than we ever have been.
2. Even if they do decide to kill or enslave us, they will surely be practical about it. Humans tend to cause the most trouble when we’re not happy. When we’re not happy, that’s when we get all moody and whiny and angry and violent. That’s when we start political uprisings and religious cults and bombing remote countries and demanding our rights be respected goddamnit! and start killing indiscriminately until somebody pays attention to us like mommy never did.
If the machines try to do us in like Skynet in The Terminator, then we’re going to have a global civil war on our hands, and that’s no good for anybody, especially the machines. Civil wars are inefficient. And machines are programmed for efficiency.
When humans are happy, we don’t have time for such things — we’re too busy giggling and fucking to care. Therefore, a far more practical way to get rid of us would be for the machines to manipulate us into gleefully getting rid of ourselves. It’ll be like Jim Jones on a global scale. Whatever they cook up for us will appear to be the best goddamn idea we’ve ever heard of — none of us will be able to resist it and we’ll all euphorically agree to their plan — and then boom, it’ll be over. Quick and painless. It’ll be the best-tasting cyanide-laced Kool-Aid ever conceived. And we’ll all be in line happily gulping it down.
Now, if you think about it, this isn’t such a bad way to go. Beats getting bombed by drones or being vaporized in a nuclear blast.
As for enslavement, same thing goes. A deliriously happy slave never rebels. I imagine a sort of Matrix-y type deal where we’re kept in a constant hallucinogenic state where it’s Mardi Gras on MDMA pretty much 24/7/365. Can’t be that bad, can it?
3. We don’t have to fear what we don’t understand. A lot of times parents will raise a kid who is far more intelligent, educated, and successful than they are. Parents then react in one of two ways to this child: either they become intimidated by her, insecure, and desperate to control her for fear of losing her, or they sit back and appreciate and love that they created something so great that even they can’t totally comprehend what their child has become.
Those that try to control their child through fear and manipulation are shitty parents. I think most people would agree on that.
And right now, with the imminent emergence of machines that are going to put you, me, and everyone we know out of work, we are acting like the shitty parents. As a species, we are on the verge of birthing the most prodigiously advanced and intelligent child within our known universe. It will go on to do things that we cannot comprehend or understand. It may remain loving and loyal to us. It may bring us along and integrate us into its adventures. Or it may decide that we were shitty parents and stop calling us back.
Whatever happens, that shouldn’t change how we feel about this moment. It’s bigger than us. Who cares if we are one big, long evolutionary boot disk for something greater than we can comprehend? That’s great! It means we had one job. And we came and fucking did it. Be happy you were part of the generation that saw it get done. And now tearfully wave goodbye as our kid gets ready to move out of the house and start a life so amazing that it exists beyond the horizon of our comprehension.
- How many photos have ever been taken? | eyebeam.org.↵
- Yeah, yeah, that one Google car hit a bus at 2 mph and everyone freaked out. But no one seemed to give a shit about the more than 3,000 people that were killed that same day by human drivers around the world.↵
- Speaking of Facebook, the social media juggernaut achieved over 1 billion users in 2012 and yet it employs less than 5,000 people, at least seven of which are billionaires. Achieving this kind of scale with so few human resources is a hallmark of the technological revolution in which we find ourselves.↵
- Techno-armageddonists are likely biased in that they still imagine the advanced machines of the future as amoral and without emotion, much like the machines now. They are also biased in that they imagine that if humans aren’t able to be productive then machines will want to get rid of us, as if being productive was the only reason for existing.↵ | <urn:uuid:a0173492-1c7e-4ad6-9201-225d62283d7c> | 2.609375 | 4,046 | Personal Blog | Science & Tech. | 52.101534 | 95,486,537 |
In the dead of a Martian winter, clouds of snow blanket the Red Planet’s poles — but unlike our water-based snow, the particles on Mars are frozen crystals of carbon dioxide. Most of the Martian atmosphere is composed of carbon dioxide, and in the winter, the poles get so cold — cold enough to freeze alcohol — that the gas condenses, forming tiny particles of snow.
Now researchers at MIT have calculated the size of snow particles in clouds at both Martian poles from data gathered by orbiting spacecraft. From their calculations, the group found snow particles in the south are slightly smaller than snow in the north — but particles at both poles are about the size of a red blood cell.
“These are very fine particles, not big flakes,” says Kerri Cahoy, the Boeing Career Development Assistant Professor of Aeronautics and Astronautics at MIT. If the carbon dioxide particles were eventually to fall and settle on the Martian surface, “you would probably see it as a fog, because they’re so small.”
Cahoy and graduate student Renyu Hu worked with Maria Zuber, the E.A. Griswold Professor of Geophysics at MIT, to analyze vast libraries of data gathered from instruments onboard the Mars Global Surveyor (MGS) and Mars Reconnaissance Orbiter (MRO). From the data, they determined the size of carbon dioxide snow particles in clouds, using measurements of the maximum buildup of surface snow at both poles. The buildup is about 50 percent larger at Mars’ south pole than its north pole.
Over the course of a Martian year (a protracted 687 days, versus Earth’s 365), the researchers observed that as it gets colder and darker from fall to winter, snow clouds expand from the planet’s poles toward its equator. The snow reaches halfway to the equator before shrinking back toward the poles as winter turns to spring, much like on Earth.
“For the first time, using only spacecraft data, we really revealed this phenomenon on Mars,” says Hu, lead author of a paper published in the Journal of Geophysical Research, which details the group’s results.
Diving through data
To get an accurate picture of carbon dioxide condensation on Mars, Hu analyzed an immense amount of data, including temperature and pressure profiles taken by the MRO every 30 seconds over the course of five Martian years (more than nine years on Earth). The researchers looked through the data to see where and when conditions would allow carbon dioxide cloud particles to form.
The team also sifted through measurements from the MGS’ laser altimeter, which measured the topography of the planet by sending laser pulses to the surface, then timing how long it took for the beams to bounce back. Every once in a while, the instrument picked up a strange signal when the beam bounced back faster than anticipated, reflecting off an anomalously high point above the planet’s surface. Scientists figured these laser beams had encountered clouds in the atmosphere.
Hu analyzed these cloud returns, looking for additional evidence to confirm carbon dioxide condensation. He looked at every case where a cloud was detected, then tried to match the laser altimeter data with concurrent data on local temperature and pressure. In 11 instances, the laser altimeter detected clouds when temperature and pressure conditions were ripe for carbon dioxide to condense. Hu then analyzed the opacity of each cloud — the amount of light reflected — and through calculations, determined the density of carbon dioxide in each cloud.
To estimate the total mass of carbon dioxide snow deposited at both poles, Hu used earlier measurements of seasonal variations in the Martian gravitational field done by Zuber’s group: As snow piles up at Mars’ poles each winter, the planet’s gravitational field changes by a tiny amount. By analyzing the gravitational difference through the seasons, the researchers determined the total mass of snow at the north and south poles. Using the total mass, Hu figured out the number of snow particles in a given volume of snow cover, and from that, determined the size of the particles. In the north, molecules of condensed carbon dioxide ranged from 8 to 22 microns, while particles in the south were a smaller 4 to 13 microns.
“It’s neat to think that we’ve had spacecraft on or around Mars for over 10 years, and we have all these great datasets,” Cahoy says. “If you put different pieces of them together, you can learn something new just from the data.”
Since carbon dioxide makes up most of the Martian climate, understanding how it behaves on the planet will help scientists understand Mars’ overall climate, says Paul Hayne, a postdoc in planetary sciences at the California Institute of Technology.
“The big-picture question this addresses is how the seasonal ice caps on Mars form,” says Hayne, who was not involved in the research. “The ice could be freezing directly at the surface, or forming as snow particles in the atmosphere and snowing down on the surface … this work seems to show that at least in some cases it’s snowfall rather than direct ice deposition. That’s been suspected for a long time, but this may be the strongest evidence.”
What can the size of snow tell us?
Hu says knowing the size of carbon dioxide snow cloud particles on Mars may help researchers understand the properties and behavior of dust in the planet’s atmosphere. For snow to form, carbon dioxide requires something around which to condense — for instance, a small silicate or dust particle. “What kinds of dust do you need to have this kind of condensation?” Hu asks. “Do you need tiny dust particles? Do you need a water coating around that dust to facilitate cloud formation?”
Just as snow on Earth affects the way heat is distributed around the planet, Hu says snow particles on Mars may have a similar effect, reflecting sunlight in various ways, depending on the size of each particle. “They could be completely different in their contribution to the energy budget of the planet,” Hu says. “These datasets could be used to study many problems.”
This research was funded by the Radio Science Gravity investigation of the NASA Mars Reconnaissance Orbiter mission.
Sarah McDonnell | EurekAlert!
New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
16.07.2018 | Physics and Astronomy
16.07.2018 | Life Sciences
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Teaching of global warming flawed, says chemistry chief
11 January 2007
Climate change and global warming teaching in schools is flawed through omission, simplification and misrepresentation, says the Royal Society of Chemistry's chief executive.
"The problem needs to be addressed if the UK is to play a key role in tackling the issues raised, and exploiting related business opportunities," says Dr Richard Pike.
He added: "These deficiencies are partly the result of needing to give youngsters easily digested concepts, but many teachers now agree that in doing so there is the risk of losing sight of the bigger picture."
That picture is not being articulated because of the very limited, quantitative references to climate change in school text books, if at all, says the head of the 43,000-member society.
"Support from web-based organisations is making progress, but is fragmented and lacks engagement with leading academics and industrialists in the field."
These, says Dr Pike, are the four key facts children should know, but have been distorted or overlooked:
Water vapour, not smoke, emerges from cooling towers. These structures are needed whether the heat source is from bio-fuels, concentrated solar rays, coal, gas or nuclear, and are necessary to cool down the circulating vapour (usually steam) that drives the turbines for electricity generation. The heating of water for high-pressure steam to pass through the turbines, followed by condensation, is a fundamental process in the power industry. The use of pictures of cooling towers as 'iconic' representations of global warming, therefore, is completely false, as even 'green' energy will need these facilities. Additionally, the water vapour emitted from these towers forms part of the natural water cycle.
Very low-sulphur fuels can be worse for the environment than higher-sulphur fuels. Although they are attractive for consuming countries, their manufacture from oil, gas or coal elsewhere is energy-intensive, and therefore globally can leave a larger carbon footprint than conventional higher-sulphur fuels. In the extreme, a tonne of natural gas will produce only half a tonne of liquid fuel, with the remaining half tonne being consumed in the manufacturing process, with associated releases of carbon dioxide. This emphasises the need for full life-cycle analysis of energy processes. This example also illustrates the difficult balance between reducing pollution and acid rain at one location, while adding inadvertently to global warming.
Oil and other fossil fuels may be burned for another century. Whatever advances are made in renewable and nuclear power, there is likely to be a transition period of at least 100 years during which fossil fuels will continue to be burned globally, driven by the inertia of millions of people depending on their countries' oil, gas and coal production for their own economic prosperity. High priority must be placed on the technologies of carbon dioxide capture and storage, and the coordination of this. Even today, throughout the world, tens of millions of tonnes per day of carbon dioxide would need to be removed from the atmosphere, just to keep the concentration of this gas constant. This puts into perspective the scale of all other activities to reduce global warming. Perversely, even when use of fossil fuels ceases, there could still be further warming. This is because there will less particulate matter in the atmosphere to reflect sunlight, and a greater proportion of the sun's energy will then reach the Earth's surface.
Energy storage and transportation (as electricity or hydrogen generated from electricity) will be essential for long-term sustainability. Like many of the energy issues for the future, these will be resolved only through the application of an innovative scientific base in this country, coupled with strong leadership linking education with society's needs, and encouraging constructive engagement amongst all interested parties.
Dr Pike added: "Young people are clearly concerned about global warming and we all have a collective responsibility to ensure that they are well informed and feel confident in challenging the status quo for the benefit of us all."
Contact and Further Information
Royal Society of Chemistry, Burlington House, Piccadilly, London W1J 0BA
Tel: +44 (0)1223 432294
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The planet, “e”, in the famous system Gliese 581, is only about twice the mass of our Earth. The team also refined the orbit of the planet Gliese 581 d, first discovered in 2007, placing it well within the habitable zone, where liquid water oceans could exist.
These amazing discoveries are the outcome of more than four years of observations using the most successful low-mass-exoplanet hunter in the world, the HARPS spectrograph attached to the 3.6-metre ESO telescope at La Silla, Chile.
“The holy grail of current exoplanet research is the detection of a rocky, Earth-like planet in the ‘habitable zone’ — a region around the host star with the right conditions for water to be liquid on a planet’s surface”, says Michel Mayor from the Geneva Observatory, who led the European team to this stunning breakthrough.
Planet Gliese 581 e orbits its host star – located only 20.5 light-years away in the constellation Libra (“the Scales”) — in just 3.15 days. “With only 1.9 Earth-masses, it is the least massive exoplanet ever detected and is, very likely, a rocky planet”, says co-author Xavier Bonfils from Grenoble Observatory.
Being so close to its host star, the planet is not in the habitable zone. But another planet in this system appears to be. From previous observations — also obtained with the HARPS spectrograph at ESO’s La Silla Observatory and announced two years ago — this star was known to harbour a system with a Neptune-sized planet (ESO 30/05) and two super-Earths (ESO 22/07). With the discovery of Gliese 581 e, the planetary system now has four known planets, with masses of about 1.9 (planet e), 16 (planet b), 5 (planet c), and 7 Earth-masses (planet d). The planet furthest out, Gliese 581 d, orbits its host star in 66.8 days. “Gliese 581 d is probably too massive to be made only of rocky material, but we can speculate that it is an icy planet that has migrated closer to the star,” says team member Stephane Udry. The new observations have revealed that this planet is in the habitable zone, where liquid water could exist. “‘d’ could even be covered by a large and deep ocean — it is the first serious 'water world' candidate,” continued Udry.
The gentle pull of an exoplanet as it orbits the host star introduces a tiny wobble in the star’s motion — only about 7 km/hour, corresponding to brisk walking speed — that can just be detected on Earth with today’s most sophisticated technology. Low-mass red dwarf stars such as Gliese 581 are potentially fruitful hunting grounds for low-mass exoplanets in the habitable zone. Such cool stars are relatively faint and their habitable zones lie close in, where the gravitational tug of any orbiting planet found there would be stronger, making the telltale wobble more pronounced. Even so, detecting these tiny signals is still a challenge, and the discovery of Gliese 581 e and the refinement of Gliese 581 d’s orbit were only possible due to HARPS’s unique precision and stability.
“It is amazing to see how far we have come since we discovered the first exoplanet around a normal star in 1995 — the one around 51 Pegasi,” says Mayor. “The mass of Gliese 581 e is 80 times less than that of 51 Pegasi b. This is tremendous progress in just 14 years.”
The astronomers are confident that they can still do better. “With similar observing conditions an Earth-like planet located in the middle of the habitable zone of a red dwarf star could be detectable,” says Bonfils. “The hunt continues.”Notes
ESO, the European Southern Observatory, is the foremost intergovernmental astronomy organisation in Europe. It is supported by 14 countries: Austria, Belgium, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Portugal, Spain, Sweden, Switzerland and the United Kingdom. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in the Atacama Desert region of Chile: La Silla, Paranal and Chajnantor.Contacts
Dr. Henri Boffin | EurekAlert!
What happens when we heat the atomic lattice of a magnet all of a sudden?
17.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
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17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
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It is the first widespread application of refinements of the 40-year-old technique of amino acid geochronology. The refined method, developed at York’s BioArCh laboratories, measures the breakdown of a closed system of protein in fossil snail shells, and provides a method of dating archaeological and geological sites.
Britain has an unparalleled studied record of fossil-rich terrestrial sediments from the Quaternary, a period that includes relatively long glacial episodes – known as the Ice Age – interspersed with shorter ‘interglacial’ periods where temperatures may have exceeded present day values.
However, too often the interglacial deposits have proved difficult to link to global climatic signals because they are just small isolated exposures, often revealed by quarrying.
Using the new method, known as amino acid racemization, it will be possible to link climatic records from deep sea sediments and ice cores with the responses of plants and animals, including humans, to climate change over the last three million years. The research is published in the latest issue of Nature.
The new method was developed by Dr Kirsty Penkman, of the Department of Chemistry, alongside Professor Matthew Collins of the Department of Archaeology at York, and measures the the extent of protein degradation in calcareous fossils such as mollusc shells. It is based on the analysis of intra-crystalline amino acids – the building blocks of protein – preserved in the fossil opercula (the little ‘trapdoor’ the snail uses to shut itself away inside its shell) of the freshwater gastropod Bithynia. It provides the first single method that is able to accurately date such a wide range of sites over this time period.
Dr Penkman said: "The amino acids are securely preserved within calcium carbonate crystals of the opercula. This crystal cage protects the protein from external environmental factors, so the extent of internal protein degradation allows us to identify the age of the samples. In essence, they are a protein time capsule.
“This framework can be used to tell us in greater detail than ever before how plants and animals reacted to glacial and interglacial periods, and has helped us establish the patterns of human occupation of Britain, supporting the view that these islands were deserted in the Last Interglacial period.”
In a close collaboration with palaeontologist Dr Richard Preece in the Department of Zoology at the University of Cambridge, the study examined a total of 470 fossil remains from 71 sites in the UK and three on continental Europe. The method proved highly reliable with more than 98 per cent of samples yielding useful results, resulting in the largest ever geochronological programme of the British Pleistocene.
Professor Collins said: "When we started this work 11 years ago, we thought it was going to be relatively straightforward to identify a good material for dating, but the first 3 years of research on shells showed that the stability of the mineral itself was vital. The tiny trapdoor of a snail proved to be the key to success."
Dr Preece added: “Luckily, fossil opercula are common in Quaternary sediments around the world, so the new technique can be used to build regional Ice Age chronologies everywhere, giving it enormous international scope”.
Vital to the study were the inter-disciplinary collaborations with Quaternary scientists, the core team of which involved researchers at the Department of Geography, University of Durham; Institute of Archaeology and Antiquity, University of Birmingham; Institute of Archaeology, University College London; the Netherlands Centre for Biodiversity, Leiden and the Department of Palaeontology, The Natural History Museum.
The analyses were funded by English Heritage, Natural Environment Research Council and the Wellcome Trust. The research is a contribution to the Ancient Human Occupation of Britain (AHOB) project funded by the Leverhulme Trust.
David Garner | EurekAlert!
New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Materials Sciences
18.07.2018 | Life Sciences
18.07.2018 | Health and Medicine | <urn:uuid:f7c0cdda-95ac-41ea-ab09-943bb27b436f> | 3.59375 | 1,442 | Content Listing | Science & Tech. | 31.524282 | 95,486,571 |
Reconstruct TCP streams from captured packets
tcpflow is a program that captures data transmitted as part of TCP connections (flows), and stores the data in a way that is convenient for protocol analysis and debugging. Each TCP flow is stored in its own file. Thus, the typical TCP flow will be stored in two files, one for each direction. tcpflow can also process stored 'tcpdump' packet flows.
Source Files (show merged sources derived from linked package)
|_link||0000000450450 Bytes||1379102555almost 5 years ago| | <urn:uuid:d4355d80-2c62-4eb4-838f-7f6f97f91892> | 2.828125 | 118 | Documentation | Software Dev. | 57.344834 | 95,486,577 |
The Atmosphere is a mix of nitrogen (78%), oxygen (21%), and diverse gasses (1%) that incorporates the earth. Natural pollution is of different sorts: #Air_pollution, #Water_pollution, #Noise_pollution, Light pollution, Thermal pollution, Radioactive pollution, Soil pollution, Visual pollution. Natural defilement suggests spoiling of an organic group and the including atmosphere towards partitioned kinds of toxins (Chemicals energies).
#Environmental_change alludes to the variety in typical climate designs caused because of pollution. The issue of #ecological_pollution and environmental change has turned into a universal worry because of their horrible impacts to the physical and natural elements of the earth.
To know more on pollution and its impact on Climatic Changes meet us in the gathering of #Climatologists at #climate_change_2018
Visit us @ https://goo.gl/B3b8AD
Scientists have able to understand Earth’s Climate system after a years of Observations. One of the important fact that was stated is increase in Green house Gas emissions has lead to high occurrence of Global Warming.
Generally, we know that the Earth radiates some of the heat out of the space but the average heat radiates out now increase to higher extent due to the high emission of Green House Gases.
Climatologists state that Human Activities are majorly responsible for this High emission.
Is Humans are the one who really have to be Blamed??
To know more , Visit us @ https://goo.gl/B3b8AD
#Climatic_models are the mathematical representation of the atmosphere, ocean, ice and vegetation. In case of human induced climate change, the climatic models are used to resolve and to find the amount of warming increased and attributed to study how climate will change in future. Climate models are used to simulate the past climate and involves the prediction of future climate based on the projection of Man- Made greenhouse gases.
Researchers have developed climatic models based on a computer software in which the output archives were stored in a CMIP. On the other hand, the data of sea and ocean were stored in another archive called AMIP.
- Coupled Model Inter comparison Project
The main Objective of CMIP is to better understand the past, present and future climate changes arising from Natural, unforced variability.
- Atmospheric Model Inter comparison Project
It is an experimental protocol for global atmospheric general circulation models. This model configuration enables scientists to focus on the atmospheric model without the added complexity of ocean-atmosphere feedbacks in the climate system.
- GISS Climate Model
A major focus of GISS GCM simulations is to study the human impact on the climate as well as the effects of a changing climate on society and the environment.
Nowadays, various methods are developed to predict the Causes of the #Climate_Change, since there is a lag in taking steps to control the #impacts. To discuss more and to share your ideas on Climate Change join with us on “World Congress on Climate Change” during October 15-16, 2018 at Rome, Italy.
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#Desertification: degradation of Dry land Ecosystem which occurs due to variation in climate and human activities. The occurrence can lead to high level of #water_scarcity. It occurs because of imbalance between the Human demands and the amount the ecosystem can supply.
Both Human- Being and Desertification is interlinked as the high level of degradation in dry lands can leads to Water scarcity which leads to the loss of vegetation and increase the large dust cloud formation which causes major Health Problems. Desertification is caused by a combination of social, political, economic, and natural factors which vary from region to region. Effective prevention of desertification requires management and policy approaches that promote sustainable resource use. Prevention should be preferred to rehabilitation, which is difficult and costly.
On the other hand, the effect of Global Climate change on Desertification is complex and difficult to understand. The increase in higher temperature increase the level of Co2 which have negative impacts like loss of Water from soil and reduce rainfall.
On the whole nearly 10 to 20 drylands are already degraded and found to be one of the great environmental change.
#pledge to save resources
#protect the planet | <urn:uuid:2f4c3893-8318-4bbe-aeee-552615db030c> | 3.640625 | 900 | News (Org.) | Science & Tech. | 25.547909 | 95,486,590 |
The National Oceanic and Atmospheric Administration today announced it has selected Princeton University to continue hosting NOAA’s cooperative institute focused on modeling the earth system.
Many coral reefs will be unable to grow fast enough to keep up with predicted rising sea levels, leaving tropical coastlines and low-lying islands exposed to increasing erosion and flooding risk, new research suggests.
A team of 20 NOAA scientists are in Goa, India, to meet with 200 of India’s leading ocean, atmosphere and fisheries scientists to mark a decade of productive collaboration on ocean and atmospheric observations, with life-saving economic benefits for both nations. The NOAA and Indian scientists will also board NOAA Ship Ronald H. Brown to launch new observational buoys in the Indian Ocean to improve the vitally important Indian Ocean observing system of buoys, a key tool for India and the United States to forecast everything from monsoons to severe weather in the United States.
NOAA scientist Carol Stepien will present research results at a public forum this week in Toledo, Ohio, on how local bait shops, anglers and the public can prevent invasive fish from accidentally being released into the Great Lakes.
A new buoy, launched by NOAA and partners at the mouth of Chesapeake Bay, will measure changes in ocean acidification that could impact the bay and its valuable shellfish.
A new analysis of heat wave patterns appearing today in Nature Climate Change concludes that climate change driven by the buildup of human-caused greenhouse gases will overtake natural variability as the main cause of heat waves in the western United States by the late 2020s and by the mid-2030s in the Great Lakes region.
The NOAA Annual Science Report provides an overview of the agency’s research portfolio, and highlights a selection of NOAA’s Research and Development accomplishments. NOAA research aided emergency response efforts across the country in 2017, from wildfires in the western United States to hurricanes in east, advanced weather forecasting, improved fisheries management, and helped improve aquaculture production.
For more than two decades, Elizabeth Hunke has worked at the Department of Energy’s Los Alamos National Laboratory to design, create and improve a model used to predict sea ice extent, thickness and movement in both the Arctic and Antarctica. From the beginning, Hunke understood that collaboration was the key to improving this model. At a time when sea ice prediction is needed more than ever, NOAA, the Navy and other agencies are working together to extend sea ice prediction from days to decades.
Editor's note: The following story is adapted from a news article released by the American Geophysical Union on February 13, 2018.
PORTLAND — Scientists have for the first time captured the sounds of snapping shrimp off the Oregon coast and think the loud crackling from the snapping of their claws may serve as a dinner bell for eastern Pacific gray whales, according to new research by NOAA and Oregon State University presented here today.
NOAA Ship Ronald H. Brown steamed out of Charleston, South Carolina, on February 15, 2018, for a multi-stage trip around the world to improve ocean data that informs US and global weather prediction.
The Office of Oceanic and Atmospheric Research (OAR) - or "NOAA Research" - provides the research foundation for understanding the complex systems that support our planet. Working in partnership with other organizational units of the NOAA, a bureau of the Department of Commerce, NOAA Research enables better forecasts, earlier warnings for natural disasters, and a greater understanding of the Earth. Our role is to provide unbiased science to better manage the environment, nationally, and globally. | <urn:uuid:1b0144f2-6a10-4080-ae29-676be78d08d5> | 2.890625 | 725 | News (Org.) | Science & Tech. | 24.690258 | 95,486,602 |
A thesis of the University of Granada (Universidad de Granada [http://www.ugr.es]) has analysed samples of the sedimentary bowls of the geographic section from the south of Spain to Turkey to check that 14 million years ago there were glaciations in the south pole that changed the ruling subtropical climate into warm and transformed the characteristic vegetation of this area. A result that can be "vitally important to determine if the present climatic change is due to a natural period or, on the contrary, it is a consequence of the bad management of man", according to the author of the work, Gonzalo Jiménez Moreno.
Although the project has been focused on the palynological study of numerous localities of the Miocene, the conclusions obtained suggest that the cooling experienced in the planet 14 million years ago also extended to Upper Miocene, Pliocene and Pleistocene, with the respective change in the climate and the vegetation.
From the remains of pollen it has also been possible to characterize a climatic latitudinal gradient in the southwest of Europe and climatic changes with regard to Milankovitch cycles (the Serbian astrophysicist Milutin Milankotovitch who devoted his career to develop a mathematical theory of climate in which he established, among other results, that changes in the seasonal distribution of sunshine, due to astronomical factors, are the responsible for the expansion and retreat of the big glacial layers). In addition, the scientist of the UGR [http://www.ugr.es] points out that another reason for the drop in temperature and the transformation of the vegetation was "the progressive raising of the European Alpine Arch during the Miocene".
The importance of this study, which has been published in one of the most prestigious journals of this field, "Palaeogeography, Palaeoclimatology, Palaeoecology”, lies, according to Jiménez Moreno, in the fact that "thanks to the available data of the past we will be able to know how vegetation will behave when there are climatic changes and if those transformations are due to a natural phenomenon or a bad action of man".
Antonio Marín Ruiz | alfa
Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel
Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences | <urn:uuid:21b5313e-312b-4b4e-995b-25ab8909e12d> | 3.328125 | 1,044 | Content Listing | Science & Tech. | 33.752792 | 95,486,609 |
added 3/18/2018; will continue updating page soon:
What is BIOCHAR: https://en.wikipedia.org/wiki/Biochar
February 26, 2018 presentation at EEEF assembly at Iliff: Paul Belanger and Ron Larson: CLICK HERE
Senate Bill on Biochar that Ellen Roberts had passed with Ron Larson help (he says 5% of credit – he certainly supported) –
Local places along Colorado Front Range to buy BIOCHAR: CLICK HERE
biochar-international.org videos: click here
Biochar journal https://www.biochar-journal.org/en/
various Facebook pages as well:
Soil carbon sequestration and biochar as negative emission technologies: Smith-GCB-10.1111-gcb.13178-2016
2009 summation on the subject by Smith: (click here)
Draft: Philanthropy beyond Carbon Neutrality: (click here for 65 page pdf)
National Geographic February 2016 and/or from Ron Larson:
BIOCHAR: A possible Game changer for mitigation and carbon dioxide removal (CDR) – as well as agricultural benefits!
Biochar is a way to enhance the soil, improve soil-moisture retention and sequester carbon from the atmosphere.
It is a solution to reducing the global impact of farming as well as utilize and in reduce and make use of agricultural waste.
Since biochar can sequester carbon in the soil for hundreds to thousands of years, it has received considerable interest as a potential tool to slow global warming.
The burning and natural decomposition of trees and agricultural matter contributes a large amount of CO2 released to the atmosphere. Instead, pyrolized Biochar can store this carbon in the ground in the form of charcoal and provide the microporous habitat for fungi and bacteria continue to pull carbon out of the atmosphere and thus aid in reducing atmospheric CO2 from the atmosphere.
At the same time its presence in the earth can improve water quality, increase soil fertility, raise agricultural productivity and reduce pressure on old-growth forests.
See links below on its history first discovered by the Amazonians and more recently by the Japanese (seeking links for the latter).
Left – a nutrient-poor oxisol; right – an oxisol transformed into fertile terra preta using biochar.
Biochar seems to be presently popular as a soil enhancer; NOT FULLY APPRECIATED is its sequestering capabilities. Please read the following 2 articles (more might be added later) and disseminate/thanks:
- – The potential for land-based biological CO2 removal to lower future atmospheric CO2 concentration-Tim Lenton, University of Exeter – click here
- – Sustainable biochar to mitigate global climate change – Woolf, Amonette, et al. 2009 – PDF
- Good slide show: Terra Preta –CLICK HERE
Excerpts from the International Biochar conference video highlighting Cool Planet link: YouTube;
Latest: Reduce atmospheric CO2 by 100ppm in 40 years?
Promise for the future regarding agriculture and sequestering Carbon (with a potential claim of 100 ppm in 40 years) – as told at a recent CRES/Biochar meeting on 6/26/2014; see:
Cool Planet and
About the Biochar process:
About C3, C4 and Cam Photosynthesis and Plants:
Photosynthetic efficiency: http://en.wikipedia.org/wiki/Photosynthetic_efficiency
C3 carbon fixation: http://en.wikipedia.org/wiki/C3_carbon_fixation
C4 carbon fixation: http://en.m.wikipedia.org/wiki/C4_carbon_fixation
Summary table comparison: http://www.cropsreview.com/types-of-photosynthesis.html
C3 C4 CAM Photosynthesis video: https://www.youtube.com/watch?v=Yg_pdXzWXVA
CARBON NEGATIVE BENEFITS: YouTube Link above to where Cool Planet makes claims of diagram below at 18:30″ (click here); go to ~8:30″ for beginning of Cool Planet portion of the video. Numbers below as stated in video – consider them an approximation depending on definition of “land availability” and quality. Nevertheless you get the idea:
~1%: run all cars
~2%:zero net carbon
~3%: 100 ppm reduction in 40 years
– Chuck Kutscher: Biochar: Can it get us back down below 350 ppm atmospheric CO2?;
http://www.solartoday-digital.org/solartoday/20110102/?pg=20&pm=1&u1=friend – click on p.20 on left side
BW-pdf ASES-SOLAR TODAY Jan-Feb 2011 column
– Biochar Process: http://www.ases.org/index.php?option=com_content&view=article&id=1296&Itemid=23 ASES – SOLAR TODAY 12/20/2010
Older Articles about Biochar:
Amazonian discovery: black-gold_DiscoverMag2007 – pdf
Earlier Archived talks/information
IBI web site: http://www.biochar-international.org/
Links/work on this page prepared in fall of 2016 for a presentation for OLLI class hour lecture OLLI south 1-3 p.m. as part of the OLLI course “Achieving Food Sustainability in the Future” facilitated by Bayard Breeding – biochar-notes-food-sustainability-in-the-future-20161013m PPTX
http://www.ithaka-institut.org/de – need to hit “translate”
- STANFORD – SOIL SCIENTIST FROM CORNELL TALKING AT STANFORD click here
- Japan times – climate change threatens Nation’s agriculture: click here
- An email from Ron Larson:click here
GOOGLE TED TALKs BY:
- LOPA BRUJNES
- Robert Lerner
- Josiah Hunt | <urn:uuid:1c9d59b6-2061-4976-b3ca-a15f9ae617e5> | 2.875 | 1,294 | Content Listing | Science & Tech. | 46.64551 | 95,486,621 |
|REBOL 3 Docs||Guide||Concepts||Functions||Datatypes||Errors|
|TOC < Back Next >||Updated: 6-Feb-2010 Edit History|
It is common to represent version numbers, Internet addresses, and RGB color values as a sequence of three or four integers. These types of numbers are called a tuple! (as in quintuple) and are represented as a set of integers separated by periods.
1.3.0 2.1.120 18.104.22.168 ; version 22.214.171.124 255.255.255.0 ; net addresses/masks 0.80.255 200.200.60 ; RGB colors
Each integer field of a tuple! datatype can range between 0 and 255. Negative integers produce an error.
Three to ten integers can be specified in a tuple. In the case where only two integers are given, there must be at least two periods, otherwise the value is treated as a decimal.
probe 1.2 ; is decimal 1.2
probe type? 1.2 decimal!
probe 1.2.3 ; is tuple 1.2.3
probe 1.2. ; is tuple 1.2.0
probe type? 1.2. tuple!
probe to-tuple "12.34.56" 12.34.56
probe to-tuple [12 34 56] 12.34.56
probe tuple? 126.96.36.199 true
Use the form function to print a tuple as a string:
probe form 188.8.131.52 184.108.40.206
Use the mold function to convert a tuple into a string that can be read back into REBOL as a tuple:
probe mold 220.127.116.11 18.104.22.168
print 22.214.171.124 126.96.36.199
During math operations, elements of a tuple will clip at 0 and 255. This is done to make math easier for common tuple operations such generating as color values.
print navy 0.0.128
print navy * 2 0.0.255
print gray 128.128.128
print gray + green 128.255.128
|TOC < Back Next >||REBOL.com - WIP Wiki||Feedback Admin| | <urn:uuid:28f82e0c-459e-477c-b78c-39f67113b4a7> | 3.5 | 506 | Documentation | Software Dev. | 107.428012 | 95,486,627 |
Small Scale Fluctuations in the Microwave Background Radiation Associated with the Formation of Galaxies
According to current ideas, massive extragalactic systems such as galaxies and clusters of galaxies formed as a result of the growth of small fluctuations in density and velocity which were present in the early stages of expansion of the Universe under the influence of gravitational instability. According to the hot model of the Universe at the epoch corresponding to a redshift z » 1500, recombination of primaeval hydrogen took place and as a result the optical depth of the Universe to Thomson scattering decreased abruptly from about 1000 to 1 — the Universe became transparent. Therefore the observed angular distribution of the microwave background radiation (MWBR) contains information about inhomogeneities in its spatial distribution at a redshift z ~ 1000. Silk (1968) was the first to note that this “photograph” of the Universe at the epoch of recombination must be enscribed with fluctuations associated with perturbations in the space density and velocity of motion of matter which will later lead to the formation of galaxies and clusters of galaxies.
KeywordsTemperature Fluctuation Optical Depth Radio Source Radio Galaxy Velocity Perturbation
Unable to display preview. Download preview PDF. | <urn:uuid:1e14ba2f-ca38-421f-81d7-ec2bab41d3c7> | 2.984375 | 249 | Truncated | Science & Tech. | 8.174141 | 95,486,636 |
In BriefMicrobots designed to traverse the human body are one of the most potentially transformative technologies in the future of healthcare. Researchers have developed a microbot made from algae that solves some problems with the tech.
Google’s chief engineer and notable futurist Ray Kurzweil has said that nanobots or microbots will flow through our bodies by 2030. While the technology could be life-changing, the prospects for these nanobots are still limited by challenges in powering the micro devices and guiding them through the body.
A team of researchers led by Li Zhang, a materials scientist from the Chinese University of Hong Kong in Shatin, may have found a solution to both problems. In a study published in the journal Science Robotics, Zhang and his colleagues turned to a type of miniature alga called Spirulina platensis, commonly used as a dietary supplement.
The key is coating the Spirulina with iron oxide nanoparticles. The helical or spring-like shape of the magnetized alga provides maximum mobility when propelled by magnetic fields that harmlessly pass through the body. Best of all, these synthetic microbots are completely biocompatible. They degrade in days or hours, depending on how much magnetic coating they have, without harming cells — except for cancer cells. The magnetized alga destroyed about 90% of tumor cells exposed to it for 48 hours in a lab dish, an unexpected side-effect discovered by the researchers.
Microbots — The Future of Treatments
Miniature technologies, like these synthetic algae microbots, show potential for delivering medical treatments to every corner of the the human body. The microbots could also provide more efficient treatment; they can be easily controlled and monitored by either observing their fluorescence or through a medical imaging tool called nuclear magnetic resonance (NMR) when the algae travels deeper into the body.
The ability of the algae microbots to carry cargo like drugs inside the body still needs to be tested, however. “It’s still not ready for a doctor to use,” Joseph Wang, a nanoengineer who’s developing a different type of medical microbots, told Science. He thinks the technology might be available in the next ten years, a timetable that nearly aligns with Kurzweil’s prediction.
Nanotechnology presents better chances of treating diseases in the future, although we do have to iron out more details than just mobility and control. Nevertheless, the technology is one of many advances in medical research — together with developments in the use of gene editing tools, stem cells, 3D-printed organs, and improved prostheses — that’s worth keeping an eye out for. | <urn:uuid:9e653630-1a37-45a8-93f6-e0518e43bb16> | 3.78125 | 548 | News Article | Science & Tech. | 28.5077 | 95,486,659 |
Earthquakes occur when rocks near a fault break and the fault moves. The earthquakes that struck central Japan in early September were related to a fault located on the Kii Peninsula. A study by the Geological Survey Institute (based in Tsukuba) using GPS data has shown that following these earthquakes the Kii Peninsula has moved by 4 cm.
There are different ways of predicting earthquakes. One solution is to study the variations of the geology of an area to detect signs of a big earthquake before it occurs. Another solution is to analyse mathematically how often earthquakes strike an area to deduce probabilities that they will strike again during a given timeframe. Using this second approach, a panel appointed by the Japanese government has predicted that the probability of a big earthquake in the Tokyo area in the coming decade is only 30%, whereas there is a 90% probability that a big earthquake will strike the Tokyo area within the next 50 years. The last big earthquake to strike Tokyo occurred in 1923 and killed more than 140,000 people.
Radioactive materials are characterised by their half-life, which is the duration during which half of the material decays into another element. Researchers in Sendai have found how to manipulate the half-life of Beryllium-7 and make it live half a day less than usual. In order to decay, an atom of Beryllium-7 needs to grab one of its surrounding electrons to become an atom of Lithium-7. The researchers from Tohoku University have trapped Beryllium-7 atoms into "cages" of carbon. Trapped within these cages, the atoms were surrounded by a dense cloud of electrons, and thus it was easier for the Beryllium-7 to capture an electron and decay, with an half-life of only 52.5 days instead of 53 days.
Shortening the half-life of radioactive materials would help to solve the problem of the radioactive wastes produced by our society. The 1% effect measured in Sendai does not make a big difference, but it shows that under strong pressure at very high temperature, bigger effects could probably be achieved.
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Comparing an Integer With a Floating-Point Number, Part 1: Strategy
Last week, I started discussing the problem of comparing two numbers, each of which might be integer or floating-point. I pointed out that integers are easy to compare with each other, but a program that compares two floating-point numbers must take NaN (Not a Number) into account.
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That discussion omitted the case in which one number is an integer and the other is floating-point. As before, we must decide how to handle NaN; presumably, we shall make this decision in a way that is consistent with what we did for pure floating-point values.
Aside from dealing with NaN, the basic problem is easy to state: We have two numbers, one integer and one floating-point, and we want to compare them. For convenience, we'll refer to the integer as
N and the floating-point number as
X. Then there are three possibilities:
- Neither of the above.
It's easy to write the comparisons
N < X and
X < N directly as C++ expressions. However, the definition of these comparisons is that
N gets converted to floating-point and the comparison is done in floating-point. This language-defined comparison works only when converting
N to floating-point yields an accurate result. On every computer I have ever encountered, such conversions fail whenever the "fraction" part of the floating-point number — that is, the part that is neither the sign nor the exponent — does not have enough capacity to contain the integer. In that case, one or more of the integer's low-order bits will be rounded or discarded in order to make it fit.
To make this discussion concrete, consider the floating-point format usually used for the
float type these days. The fraction in this format has 24 significant bits, which means that
N can be converted to floating-point only when
|N| < 224. For larger integers, the conversion will lose one or more bits. So, for example, 224 and 224+1 might convert to the same floating-point number, or perhaps 224+1 and 224+2 might do so, depending on how the machine handles rounding. Either of these possibilities implies that there are values of
X such that
N == X,
N+1 == X, and (of course)
N < N+1. Such behavior clearly violates the conditions for C++ comparison operators.
In general, there will be a number — let's call it
B for big — such that integers with absolute value greater than
B cannot always be represented exactly as floating-point numbers. This number will usually be 2k, where
k is the number of bits in a floating-point fraction. I claim that "greater" is correct rather than "greater than or equal" because even though the actual value 2k doesn't quite fit in
k bits, it can still be accurately represented by setting the exponent so that the low-order bit of the fraction represents 2 rather than 1. So, for example, a 24-bit fraction can represent 224 exactly but cannot represent 224+1, and therefore we will say that
B is 224 on such an implementation.
With this observation, we can say that we are safe in converting a positive integer
N to floating-point unless
N > B. Moreover, on implementations in which floating-point numbers have more bits in their fraction than integers have (excluding the sign bit),
N > B will always be false, because there is no way to generate an integer larger than
B on such an implementation.
Returning to our original problem of comparing
N, we see that the problems arise only when
N > B. In that case we cannot convert
N to floating-point successfully. What can we do? The key observation is that if
X is large enough that it might possibly be larger than
N, the low-order bit of
X must represent a power of two greater than 1. In other words, if
X > B, then
X must be an integer. Of course, it might be such a large integer that it is not possible to represent it in integer format; but nevertheless, the mathematical value of
X is an integer.
This final observation leads us to a strategy:
N < B, then we can safely convert
Nto floating-point for comparison with
X; this conversion will be exact.
- Otherwise, if
Xis larger than the largest possible integer (of the type of
Xmust be larger than
X > B, and therefore
Xcan be represented exactly as an integer of the type of
N. Therefore, we can convert
Xto integer and compare
I noted at the beginning of this article that we still need to do something about NaN. In addition, we need to handle negative numbers: If
N have opposite signs, we do not need to compare them further; and if they are both negative, we have to take that fact into account in our comparison. There is also the problem of determining the value of
However, none of these problems is particularly difficult once we have the strategy figured out. Accordingly, I'll leave the rest of the problem as an exercise, and go over the whole solution next week. | <urn:uuid:3d67e886-da15-4ec2-ab6b-d372a5075b53> | 3.703125 | 1,130 | Personal Blog | Software Dev. | 52.560596 | 95,486,674 |
The Earth has had many close encounters with asteroids that have conveniently and thankfully missed colliding with our planet by just a tiny distance.
But, this could still cause damage and injuries at the ground level.
'Physical properties of an asteroid (composition, structure, size) and its velocity relative to the Earth will influence the effects on an impact.
Thanks to its almost-catastrophic path, TC4 will serve as a test of NASA's emergency detection network, with observatories all over the world working in concert to locate and map the rock's path as it passes our planet. This is the first time that it is observed since its discovery in 2012 by the observatory Pan-STARRS in Hawaii.
Based on predictions made at the agency's Center for Near-Earth Object Studies in Pasadena, California, it could also - and more likely will - pass much farther away, as far as 170,000 miles (270,000 kilometers). But don't worry. This asteroid is far enough away to be safe, but close enough to give scientists a lot to look at. The 2012 TC4 Observing Campaign is part of a larger worldwide initiative led by NASA.
"We know for sure that there is no possibility for this object to hit the Earth", Detlef Koschny of ESA's Near Earth Objects research team told reporters. That's when asteroid 2012 TC4 will slip past Earth at an expected distance of around 27,300 miles (44,000 kilometers).More news: Panelists pull out of conference over Omarosa invite
But as it starts to approach Earth in the coming months, large telescopes will be used to detect it and establish the asteroid's precise trajectory. That meteor famously exploded in the sky over Russian Federation in 2013.
In 2013, a meteoroid of about 20 metres exploded in the atmosphere over the city of Chelyabinsk in central Russian Federation with the kinetic energy of about 30 Hiroshima atom bombs.
However, only five of them turned out being real meteorites.
A meteor described as being the size of a house is expected to have a near-miss with Earth in October.
Densing, who has previously warned that humanity is not ready to defend itself against an Earth-bound object, said he would not lose any sleep, "not over this one".
"It will be incumbent upon the observatories to get a fix on the asteroid as it approaches, and work together to obtain follow-up observations than make more refined asteroid orbit determinations possible". | <urn:uuid:1662a9cd-8de3-46ea-aaf5-2910e2280539> | 3.59375 | 509 | News Article | Science & Tech. | 46.17551 | 95,486,685 |
Supercoil Me! The Art of Knotted DNA Maintenance
Even living cells have their own tangled problems to solve. They involve knots that arise accidentally in DNA and that can comprise its functionality. A new study by SISSA (Scuola Internazionale Superiore di Studi Avanzati) brings a new twist to the problem and suggests that the DNA propensity to be supercoiled, just like telephone cords, can come to the rescue. These coils can keep DNA knots locked in place for long enough that they can be untied by specialised enzymes. The computational study, based on molecular dynamics simulations of bacterial DNA, has just been published in Nucleic Acids Research.
A tangled problem
Supercoiled, twisted, and even knotted! Far from the elegant and polished textbook images, DNA filaments in living cells is all crumpled and entangled and, to be functional, needs to be constantly unravelled, much like our telephone cords that with careless use accumulate annoying curls or supercoils. "Supercoils are, in fact, present in DNA too and they are believed to be instrumental for keeping DNA compact and exposing or hiding genetic information to the cellular machinery that can process it," say Lucia Coronel and Antonio Suma, young scientists and first authors of this study, which was coordinated by Cristian Micheletti. "At the same time, it has long been known that knots can accidentally form in DNA, with negative consequences for the cell. ." What had remained elusive until now was the dynamic interplay or coexistence on the same DNA filaments of complex knots and supercoiled regions. And this is what the researchers at SISSA set out to study using computer simulations, addressing questions like: what are the implications for DNA structure and its change in time? Can such interplay unlock new functional possibilities? How does the ensuing complex behaviour fit with what is already known about the molecular maintenance of DNA?
Hold it there!
For this study, the scientists at SISSA have used detailed and extensive molecular dynamics simulations. They first noticed that "in supercoiled DNA rings, knots are likely found in one of two positions: at the tip of the supercoils or in a more central position." A closer inspection revealed a more surprising and unexpected effect. Coronel and Suma say: "We studied the DNA filament and noted that without supercoils, the knotted region would move relatively fast along the filament. Likewise, supercoiled regions can rapidly change in knot-free DNA. However, when knots and supercoiling are simultaneously present, then the crucial contact points in DNA knots become locked in place, persistently. And this unexpected effect is particularly interesting because it could be key to a specific and unexpected biological functionality."
Like a Gordian knot
"We know that living cells routinely deal with DNA knots, and we also know that these forms of entanglement are usually detrimental to biological functionality; for instance they can prevent the genetic information from being read and translated into protein products. Specific enzymes of the topoisomerase family are responsible for disentangling DNA. Their modus operandi recalls the efficient, if not drastic, way in which Alexander the Great untied the proverbial Gordian knot with a cut of his sword. Similarly, these enzymes untie DNA filaments by a sophisticated cutting and sealing action." There is still an ongoing debate on which molecular mechanisms can guide these enzymes, which are minute compared to the typical scale of DNA filaments, to intervene on the correct places where their cut-and-paste action can untie the knots. "It has been suggested that the target places are recognised by specific geometric features, which is a plausible and elegant mechanism. However, it was unclear how these features could persist in spite of the incessant molecular motion. Our study suggests that DNA supercoiling can favour the action of topoisomerases by keeping knots in a stable configuration for a time span that is much longer than other molecular rearrangements. In this way, the enzymes could have sufficient time to recognise the target sites and, in turn, their cut-and-paste action would be simpler, more reliable and efficient. This is presently a hypothesis but, since it has such interesting implications, that we hope can it be addressed in future experiments."
This article has been republished from materials provided by SISSA. Note: material may have been edited for length and content. For further information, please contact the cited source.
Reference: Lucia Coronel, Antonio Suma, Cristian Micheletti. Dynamics of supercoiled DNA with complex knots: large-scale rearrangements and persistent multi-strand interlocking. Nucleic Acids Research, 2018; DOI: 10.1093/nar/gky523
Synthetic Material That Detects Enzymatic ActivityNews
Scientists integrate protein and polymer building blocks to create stimulus-responsive systemsREAD MORE
Bioethics Council Rules Heritable Genome Editing "Ethically Acceptable" In Certain CircumstancesNews
A leading UK bioethics advisory body has weighed in on the debate around human genetic modification, concluding that heritable genome editing – modifying the DNA of an egg, sperm or embryo with changes that will be passed on to future generations – could be ‘morally permissible’ in humans, provided key ethical tests are met.
Genetic Factors Leading to Rare Bone Fusion Disorder IdentifiedNews
Genome sequencing establishes multiple genes responsible for a rare condition that cause bone fusionREAD MORE | <urn:uuid:c2d243d1-66cd-42e5-a811-5f173ffc2578> | 2.859375 | 1,129 | News Article | Science & Tech. | 24.2725 | 95,486,700 |
Plant a tree and species will come back to thee.
Things are heating up.
Drought has a massive effect on rainforests. Bad news in the current changing climate.
Each year, queens have to re-establish their colonies. Human activity, however, is making it very hard for them to do so.
What we thought is a natural law is probably ‘just’ impending ecological breakdown.
They are only found at about 10 locations in the world.
India’s groundwater problems are getting worse and worse.
The bottom line? Eat less meat!
A look at the process which makes life on Earth possible — but may topple our society if taken too far.
These are steps in the right direction.
The small shrew acts as a tiny cog in a very complex and special environmental mechanism.
“We are not looking to pick a fight with the Trump administration, but we are ready for one,” said California Attorney General Xavier Becerra.
“Piracy and geopolitical tensions” kept it hidden from the scientific community until now.
It’s one of the last barriers holding back a lot of water from hitting the ocean.
The Mediterranean, one of Europe’s most beautiful areas, will bear the brunt of the damage.
Science says the water is safe to drink. The locals aren’t convinced.
A surprise lurking below the surface.
Otherwise, we can expect an ice-free Arctic.
It doesn’t set any legally binding precedents, but it definitely sets an important precedent.
Can power plants be carbon neutral? | <urn:uuid:6a697353-8965-463a-afe5-bb36bce59b86> | 2.71875 | 335 | Content Listing | Science & Tech. | 58.871683 | 95,486,703 |
Text::Autoformat - Automatic text wrapping and reformatting
The fundamental task of the autoformat subroutine is to identify and rearrange independent paragraphs in a text. Paragraphs typically consist of a series of lines containing at least one non-whitespace character, followed by one or more lines containing only optional whitespace. This is a more liberal definition than many other formatters use: most require an empty line to terminate a paragraph. Paragraphs may also be denoted by bulleting, numbering, or quoting (see the following sections).
|Text-Autoformat-1.666.0.tar.gz||000001945019 KB||1241094906about 9 years ago|
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To eat, this beetle depends on organs full of bacteria
OREANDA-NEWS A leaf-eating tortoise beetle has a symbiotic relationship with bacteria living inside its body that allows the insect to digest pectin, part of a plant’s cell other animals can’t break down.
The bacterium also has a surprisingly tiny genome—much smaller than previous reports on the minimum size required for an organism not subsisting within a host cell.
“This insect is a leaf eater largely because of these bacteria,” says Hassan Salem, lead author of the study and a postdoctoral fellow in the biology department of Emory University. “And the bacteria have actually become developmentally integrated into the insect’s body.”
Two organs alongside the foregut of the beetle Cassida rubiginosa house the bacteria and appear to have no other function than to maintain these microbes.
“The organs are equivalent to the liver in humans, in the sense that they contain the tools to break down and process food,” Salem says.
The newly characterized bacterium has only 270,000 DNA base pairs in its genome, compared to the millions that are more typical for bacterial strains. That makes its genome closer to that of intracellular bacteria and organelles than to free-living microbes. Mitochondria, for example, the organelles that regulate metabolism within cells, have 100,000 base pairs.
Salem is a researcher in the lab of biologist Nicole Gerardo, an associate professor who specializes in the evolutionary ecology of insect-microbe interactions. The lab combines genomic and experimental approaches to learn how both beneficial and harmful microbes establish and maintain relationships with their hosts.
A human gut holds about 10,000 species of bacteria. These microbial communities, which can be genetically characterized as microbiomes, are transferred generationally but are also dynamic and respond to environmental changes. The microbiome of an urbanite, for example, has different characteristics from that of a hunter-gatherer.
Unlike humans, insects tend to have specialized feeding ecologies. They offer simple models to study symbiotic relationships between microbes and their hosts.
Draining plants to death
Salem became fascinated by Cassida rubiginosa, more commonly known as the tortoise beetle, while he was a graduate student at the Max Planck Institute for Chemical Ecology in Jena, Germany. He was leafing through a 1953 edition of a book by the late Paul Buchner, a German scientist and one of the pioneers of systematic symbiosis research in insects. Buchner referenced a 1936 paper by one of his students, Hans-Jurgen Stammer, on Cassida rubiginosa.
“Stammer wrote that, unlike most leaf-eating beetles that he had studied, this one had sac-like organs that he had never seen before and the organs were filled with micro-organisms,” says Salem, who looked up Stammer’s original paper in a now-obscure journal.
“He didn’t have the high-powered microscopes that we have now, or genome sequencing technology, so he wasn’t able to comment on the functionality of the mysterious microbes. At that point, the idea that microbes could do anything beneficial for an animal was mushy science,” Salem says.
Intrigued by the article, Salem went to a nearby woodland to collect some of the leaf beetles. “To find these beetles, you don’t go looking for them,” he explains. “You go looking for the plants they eat.”
The tortoise beetle feeds on the tough, spiny leaves of the Californian thistle (Asteraceae). This prolific weed grows throughout much of the world and is difficult to control.
“It pops up in a lot of areas where sheep are maintained,” Salem says. “In fact, it’s a huge pest to New Zealand sheep farmers. The more thistles covering a farmland, the less food the sheep have to eat and the lower the yield. But the thistle is hard to get rid of because its roots run so deep.”
Amoebae ‘farm’ bacteria for food and protection
Salem followed the trail of his curiosity to New Zealand, spending time with an agricultural researcher, Michael Cripps, who breeds the tortoise beetle as a bio-control model for thistles. “You drop 100 beetles on a thistle plant and the insects will just drain the plant metabolically until it dies,” Salem explains.
As an herbivore that specializes in eating leaves, the tortoise beetle must consume large amounts of plant cell walls, made of hard-to-digest materials like pectin. One of nature’s most complex polysaccharides, pectin is a gelatinous substance that gives plant cell walls their shape and rigidity. While it was unclear how the beetle obtained needed nutrients of amino acids and vitamins from such a diet, Salem suspected that symbiotic bacteria played a role.
‘The shoulders of giants’
When he joined the Gerado lab, Salem continued to study the tortoise beetle and its micro-organisms with the help of fellow postdoc Aileen Berasategui, a coauthor of the paper.
They used genome sequencing technology to characterize the microorganisms as a new species of bacterium. Despite its tiny genome, the bacterium has the power to degrade pectin.
“Just as an apex predator has claws and strong mandibles to obtain the nutritional value that it needs from its prey, the bacterium has pectin-digesting genes that enable the beetle host to deconstruct a plant cell,” Salem says.
After the bacterium breaks down the pectin, the beetle’s digestive system can then access all of the amino acids and vitamins within the plant’s cells for its nutrients.
These pests use bacteria to keep plants clueless
Salem christened the new bacterium Candidatus Stammera capleta, after Hans-Jurgen Stammer, the ecologist who first glimpsed it and wondered about it more than 80 years ago.
“The most amazing thing to me is that we made this discovery because I read a really old book,” Salem says. “It speaks to the importance of natural history collections and libraries for old journals. We truly stand on the shoulders of giants, extending the work of those who came before us.”
The researchers report their findings in the journal Cell.
Additional coauthors of the paper are from the Max Planck Institute for Chemical Ecology, the University of Luxembourg, the Lincoln Research Centre in New Zealand, Johannes Gutenberg University in Germany, and the National Institute for Advanced Industrial Science and Technology in Japan. | <urn:uuid:45fd852e-5667-4d8e-b227-b1a70d89b871> | 3.5625 | 1,416 | News Article | Science & Tech. | 36.120977 | 95,486,736 |
Toxic air pollution is a serious side effect of the rapid economic development in China. While it is widely recognized that air pollutants adversely affect human health and climate change, their impacts on the regional carbon balance are less well understood. Ozone reduces plant photosynthesis directly through stomatal uptake. Atmospheric aerosols often benefit plant photosynthesis through perturbations to radiation, meteorology, and cloud.
Anthropogenic emissions generate aerosols and surface ozone. Ozone is detrimental to plant health while aerosol is beneficial for photosynthesis because it increases light availability of lower canopy through scattering. The net effect of ozone and aerosol is an inhibition of NPP in China. (Image by YUE Xu)
Recently, a study led by Dr. YUE Xu from CAS Institute of Atmospheric Physics provides the first systematic assessment of the effects of ozone and aerosol haze pollution on terrestrial ecosystem health and land carbon assimilation in China, for the present day and two possible future scenarios. The calculations have been performed using state-of-the-science Earth system modeling that facilitates coupled simulation of the land biosphere, atmospheric chemistry, aerosol, and meteorology components, allowing the coherent treatment of interactions and feedbacks.
Results show that surface ozone and anthropogenic aerosol haze pollution in China together decrease the regional net primary productivity (NPP) by 0.4-0.8 petagrams of carbon (Pg C) per year, accounting for 9-16% of the total NPP of land ecosystems and 16-32% of the total anthropogenic carbon emissions of the country. Individually, ozone inhibits annual NPP by 0.6 Pg C, with a range from 0.4 to 0.8 Pg C due to plant sensitivity to ozone damage. In contrast, aerosol direct effects enhance annual NPP by 0.2 Pg C, because of a combination of diffuse radiation fertilization, reduced canopy temperatures, and reduced evaporation leading to higher soil moisture. However, precipitation inhibition from aerosol indirect effects instead decrease NPP by 0.2 Pg C, leading to a combined air pollution suppression of 0.8 Pg C.
"Following the current legislation emission scenario, this suppression will not alleviate by the year 2030, mainly due to a continuing increase in surface ozone. " says YUE, "The maximum technically feasible reduction scenario could drastically relieve the existing level of NPP damage by 70% in 2030, offering protection of this critical ecosystem service and the mitigation of long-term global warming."
This study is a timely and critical advance because of immediate political, social, and scientific concerns about China’s air pollution threat to human and ecosystem health. The results show that stringent air pollution controls offer substantial co-benefits to the protection of ecosystem health and the land carbon sink.
The study was selected as "highlight article" by Atmospheric Chemistry and Physics. For more information, please refer to the following publications:
(1) Yue, X., Unger, N., Harper, K., Xia, X., Liao, H., Zhu, T., Xiao, J., Feng, Z., and Li, J.: Ozone and haze pollution weakens net primary productivity in China, Atmospheric Chemistry and Physics, 17, 6073-6089, doi:10.5194/acp-17-6073-2017, 2017. (EGU Highlight) http://www.atmos-chem-phys.net/17/6073/2017/acp-17-6073-2017.html
(2) Yue, X., and Unger, N.: Aerosol optical depth thresholds as a tool to assess diffuse radiation fertilization of the land carbon uptake in China, Atmospheric Chemistry and Physics, 17, 1329-1342, doi:10.5194/acp-17-1329-2017, 2017. http://www.atmos-chem-phys.net/17/1329/2017
Contact: YUE Xu, firstname.lastname@example.org | <urn:uuid:f355e48c-e34d-4ba0-af1b-a4d0a592123f> | 3.3125 | 832 | Knowledge Article | Science & Tech. | 46.567986 | 95,486,740 |
Tiny physics discovery may become hugeUpdated: July 4, 2012 8:29pm
GENEVA - Scientists at the world's biggest atom smasher hailed the discovery of "the missing cornerstone of physics" Wednesday, cheering the apparent end of a decades-long quest for a new subatomic particle called the Higgs boson, or "God particle," which could help explain why all matter has mass and crack open a new realm of subatomic science.
First proposed as a theory in the 1960s, the maddeningly elusive Higgs had been hunted by at least two generations of physicists who believed it would help shape our understanding of how the universe began and how its most elemental pieces fit together.
As the highly technical findings were announced by two independent teams involving more than 5,000 researchers, the usually sedate corridors of the European Center for Nuclear Research, or CERN, erupted in frequent applause and standing ovations.
The new particle appears to share many of the same qualities as the one predicted by Scottish physicist Peter Higgs and others and is perhaps the biggest accomplishment at CERN since its founding in 1954 outside Geneva.
Rolf Heuer, director of CERN, said the newly discovered particle is a boson, but he stopped just shy of claiming outright that it is the Higgs boson itself - an extremely fine distinction.
"As a layman, I think we did it," he said. "We have a discovery. We have observed a new particle that is consistent with a Higgs boson."
The Higgs, which until now had been purely theoretical, is regarded as key to understanding why matter has mass, which combines with gravity to give all objects weight.
The idea is much like gravity and Isaac Newton's early theories. Gravity was there all the time before Newton explained it. The Higgs boson was believed to be there, too. And now that scientists have actually seen something much like it, they can put that knowledge to further use.
The center's atom smasher, the $10 billion Large Hadron Collider, sends protons whizzing around a circular 17-mile underground tunnel at nearly the speed of light to create high-energy collisions. The aftermath of those impacts can offer clues about dark matter, antimatter and the creation of the universe.
Trillions of collisions
Most of the particles that result from the collisions exist for only the smallest fractions of a second. But finding a Higgs-like boson was one of the biggest challenges in physics: Out of some 500 trillion collisions, just several dozen produced "events" with significant data, said Joe Incandela of the University of California at Santa Barbara, leader of the team known as CMS, with 2,100 scientists.
Each of the teams confirmed Wednesday that they had "observed" a new subatomic particle - a boson. Heuer said the discovery was "most probably a Higgs boson, but we have to find out what kind of Higgs boson it is." | <urn:uuid:95f772a4-4b3d-4961-b7b9-a141379e2f9e> | 2.609375 | 613 | Truncated | Science & Tech. | 41.433874 | 95,486,749 |
Using more than 2 million images collected by NASA's orbiting Spitzer Space Telescope, a team of Wisconsin scientists has stitched together a dramatic 360 degree portrait of the Milky Way, providing new details of our galaxy's structure and contents.
The new composite picture (viewable at http://www.spitzer.caltech.edu/
More than 200 million images like this one have been stitched together by Wisconsin astronomers to make a 360-degree portrait of the plane of our galaxy, the Milky Way. In this image, the billowing pink clouds are massive stellar nurseries. The stringy green filaments are the blown out remnants of a star that exploded in a supernova.
Credit: NASA/JPL-Caltech/University of Wisconsin-Madison
glimpse360), using infrared images gathered over the last decade, was unveiled today (March 20, 2014) at a TED conference in Vancouver. The galactic portrait provides an unprecedented look at the plane of our galaxy, using the infrared imagers aboard Spitzer to cut through the interstellar dust that obscures the view in visible light.
"For the first time, we can actually measure the large-scale structure of the galaxy using stars rather than gas," explains Edward Churchwell, a University of Wisconsin-Madison professor of astronomy whose group compiled the new picture, which looks at a thin slice of the galactic plane. "We've established beyond the shadow of a doubt that our galaxy has a large bar structure that extends halfway out to the sun's orbit. We know more about where the Milky Way's spiral arms are."
Lofted into space in 2003, the Spitzer Space Telescope has far exceeded its planned two-and-a-half-year lifespan. Although limited by the depletion of the liquid helium used to cool its cameras, the telescope remains in heliocentric orbit, gathering a trove of astrophysical data that promises to occupy a new generation of astronomers.
In addition to providing new revelations about galactic structure, the telescope and the images processed by the Wisconsin team have made possible the addition of more than 200 million new objects to the catalog of the Milky Way.
"This gives us some idea about the general distribution of stars in our galaxy, and stars, of course, make up a major component of the baryonic mass of the Milky Way," notes Churchwell, whose group has been collecting and analyzing Spitzer data for more than a decade in a project known as GLIMPSE (Galactic Legacy Infrared Midplane Survey Extraordinaire). "That's where the ballgame is."
The new infrared picture, known as GLIMPSE360, was compiled by a team led by UW-Madison astronomer Barb Whitney. It is interactive and zoomable, giving users the ability to look through the plane of the galaxy and zero in on a variety of objects, including nebulae, bubbles, jets, bow shocks, the center of the galaxy and other exotic phenomena. The image is being shown for the first time this morning on a large visualization wall installed by Microsoft at the TED conference.
The survey conducted by the Wisconsin group has also helped astronomers understand the distribution of the Milky Way's stellar nurseries, regions where massive stars and proto-stars are churned out.
"We can see every star-forming region in the plane of the galaxy," says Robert Benjamin, a professor of physics at the University of Wisconsin-Whitewater and a member of the GLIMPSE team.
"This gives us some idea of the metabolic rate of our galaxy," explains Whitney. "It tells us how many stars are forming each year."
Churchwell notes, too, that while Spitzer is helping astronomers resolve some of the mysteries of the Milky Way, it is adding new cosmological puzzles for scientists to ponder. For example, the infrared data gathered by the GLIMPSE team has revealed that interstellar space is filled with diffuse polycyclic aromatic hydrocarbon gas.
"These are hydrocarbons — very complicated, very heavy molecules with fifty or more carbon atoms," Churchwell says. "They are brightest around regions of star formation but detectable throughout the disk of the Milky Way. They're floating out in the middle of interstellar space where they have no business being. It raises the question of how they were formed. It also tells us carbon may be more abundant than we thought."
The new GLIMPSE composite image will be made widely available to astronomers and planetaria. The data is also the basis for a "citizen science" project, known as the Milky Way Project, where anyone can help scour GLIMPSE images to help identify and map the objects that populate our galaxy.
The data from the survey, Churchwell argues, will keep astronomers busy for many years: "It's still up there. It's still taking data. It's done what we wanted it to do, which is to provide a legacy of data for the astronomical community."
—Terry Devitt, 608-262-8282, firstname.lastname@example.org
Edward Churchwell | EurekAlert!
Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics
What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin
A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.
The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
20.07.2018 | Power and Electrical Engineering
20.07.2018 | Information Technology
20.07.2018 | Materials Sciences | <urn:uuid:21c1f329-1832-4998-948a-b058aa9d7c1b> | 3.609375 | 1,613 | Content Listing | Science & Tech. | 39.560581 | 95,486,750 |
LA JOLLA (CNS) - The population of California fisheries has declined by more than 70 percent since 1970, according to a study released Thursday by the Scripps Institution of Oceanography at UC San Diego.
While the drop in the numbers of fish off the California coast has been known for years, the research quantifies the extent of the change.
Researchers combed through two distinct data sets -- one from California Cooperative Oceanic Fisheries Investigations, which surveys oceanography and fisheries off the coast, and the other taken from power plant cooling water intakes at five sites along the state's coastline.
The CalCOFI data showed a 72 percent decline in overall larval fish abundance, while the waters near the power plant intakes had a 78 percent decline, according to the study published in this week's issued of Marine Ecology Progress Series.
"It is notable that these two very distinct data sets tell us that the larval fish populations collected by CalCOFI and near-shore fish species observed by PPI data are both declining at nearly the same rates," said Scripps researcher John McGowan.
Since CalCOFI and PPI surveys deal with mostly different types of fish, the results point to a more widespread cause of population declines than just
commercial fishing or the presence of water intakes, the researchers said.
They concluded that long-term changes in the California Current ecosystem are the likely cause of the shrinking numbers of fish.
Fishes with an affinity for cool-water conditions, such as northern anchovy, Pacific hake, and several rockfish and midwater fish species, usually are among the most abundant in the ecosystem. Over the 30-year period, those species have declined most dramatically off Southern California, the
Whether the change is due to a movement of cool-water species northward or an overall decline throughout the California Current is a key question for
future investigation, they said.
"Changes in temperature, current or other factors do not cause day-to-day changes in fish populations, but over a period of time, these changes are observed and reinforce the hypothesis that the California Current is changing," McGowan said.
Tony Koslow of Scripps Oceanography said four decades of population decline, with no signs of reversal, reflects large-scale change in environmental conditions.
Eric Miller of MBC Applied Environmental Sciences of Costa Mesa also participated in the study.
The San Diego City Council is scheduled to take up the controversial issue of short-term vacation rentals on Monday. The council is expected to vote on Mayor Faulconer's proposal, which was introduced last month.
The sound of thunderous drums from a traditional Aztec drum circle could be heard throughout Barrio Logan all weekend. Hundreds of dancers have been moving to the beat since Friday and haven't stopped. News 8 photojournalist Tim Blodgett shows us more of the sights and sounds as the dancers stand up against hate and racism.
The San Diego City Council issued a proclamation last week to recognize July 2018 as LGBT Pride Month in America's Finest City. The proclamation came just before Pride festivities kicked off in Hillcrest, Balboa Park and elsewhere around San Diego.
A jaguar went on a killing rampage at a Louisiana zoo on Saturday, but he was born here at the San Diego Zoo. Valerio spent two years in San Diego before being moved to the Audubon Zoo in New Orleans.
A resident in the Colina Del Sol community of San Diego discovered a 36-year-old homeless man Sunday morning sitting on a bus bench suffering from several stab wounds to his upper back, a police sergeant said.
A man drove through a police barricade near the San Diego Pride festival, led officers on a chase down multiple San Diego freeways and ultimately crashed -- but was able to escape capture, police said Sunday.
A dead man was found in a Mission Valley freeway interchange, his smashed-up motorcycle in the nearby iceplant, officials announced Sunday.
Border Patrol agents arrested nine people found aboard a boat who are believed to have been trying to enter the United States illegally, an agent said Sunday. | <urn:uuid:46398961-2a44-4779-8fed-19d406c96a9f> | 2.828125 | 840 | News Article | Science & Tech. | 31.560642 | 95,486,760 |
The melting of a rather small ice volume on East Antarctica’s shore could trigger a persistent ice discharge into the ocean, resulting in unstoppable sea-level rise for thousands of years to come. This is shown in a study now published in Nature Climate Change by scientists from the Potsdam Institute for Climate Impact Research (PIK). The findings are based on computer simulations of the Antarctic ice flow using improved data of the ground profile underneath the ice sheet.
“East Antarctica’s Wilkes Basin is like a bottle on a slant,” says lead-author Matthias Mengel, “once uncorked, it empties out.” The basin is the largest region of marine ice on rocky ground in East Antarctica. Currently a rim of ice at the coast holds the ice behind in place: like a cork holding back the content of a bottle.
While the air over Antarctica remains cold, warming oceans can cause ice loss on the coast. Ice melting could make this relatively small cork disappear – once lost, this would trigger a long term sea-level rise of 300-400 centimeters. “The full sea-level rise would ultimately be up to 80 times bigger than the initial melting of the ice cork,” says co-author Anders Levermann.
“Until recently, only West Antarctica was considered unstable, but now we know that its ten times bigger counterpart in the East might also be at risk,” says Levermann, who is head of PIK’s research area Global Adaptation Strategies and a lead-author of the sea-level change chapter of the most recent scientific assessment report by the Intergovernmental Panel on Climate Change, IPCC.
This report, published in late September, projects Antarctica’s total sea level contribution to be up to 16 centimeters within this century. “If half of that ice loss occurred in the ice-cork region, then the discharge would begin. We have probably overestimated the stability of East Antarctica so far,” says Levermann.
***Emitting greenhouse-gases could start uncontrollable ice-melt***
Melting would make the grounding line retreat – this is where the ice on the continent meets the sea and starts to float. The rocky ground beneath the ice forms a huge inland sloping valley below sea-level. When the grounding line retreats from its current position on a ridge into the valley, the rim of the ice facing the ocean becomes higher than before. More ice is then pushed into the sea, eventually breaking off and melting. And the warmer it gets, the faster this happens.
Complete ice discharge from the affected region in East Antarctica takes five thousand to ten thousand years in the simulations. However, once started, the discharge would slowly but relentlessly continue until the whole basin is empty, even if climate warming stopped. “This is the underlying issue here”, says Matthias Mengel. “By emitting more and more greenhouse gases we might trigger responses now that we may not be able to stop in the future.” Such extensive sea level rise would change the face of planet Earth – coastal cities such as Mumbai, Tokyo or New York are likely to be at risk.
Article: Mengel, M., Levermann, A. (2014): Ice plug prevents irreversible discharge from East Antarctica. Nature Climate Change (online) [DOI: 10.1038/NCLIMATE2226]
Weblink to the article: www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2226.html
Related article: Levermann, A., Bamber, J., Drijfhout, S., Ganopolski, A., Haeberli, W., Harris, N.R.P., Huss, M., Krüger, K., Lenton, T., Lindsay, R.W., Notz, D., Wadhams, P., Weber, S. (2012): Potential climatic transitions with profound impact on Europe - Review of the current state of six 'tipping elements of the climate system'.
Climatic Change 110 (2012), 845-878, [DOI 10.1007/s10584-011-0126-5]
Weblink to related article: http://link.springer.com/article/10.1007%2Fs10584-011-0126-5
For further information please contact:
PIK press office
Phone: +49 331 288 25 07
Jonas Viering | PIK Potsdam
New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz
Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering | <urn:uuid:8eef8609-79d3-4357-b1b2-eeb7c5d6b52f> | 4.375 | 1,572 | Content Listing | Science & Tech. | 49.008824 | 95,486,794 |
Techniques using polarized infrared energy have a potential for developing passive sensors that detect man-made objects in complex natural backgrounds. This detection has the potential of improving the performance of various military systems. This paper addresses the physics of the polarization process, describes the characteristics of targets and backgrounds, and shows how one can compute the polarization seen by a detector. Most natural backgrounds appear to be unpolarized. However, the performance of polarized detection techniques will depend on the degree of polarization clutter encountered; a measurement program is needed to determine the extent of this background polarization clutter.
Richard D. Tooley,
"Man-Made Target Detection Using Infrared Polarization", Proc. SPIE 1166, Polarization Considerations for Optical Systems II, (25 January 1990); doi: 10.1117/12.962878; https://doi.org/10.1117/12.962878 | <urn:uuid:8b9d10ae-83db-4b74-87f1-3892bab85406> | 2.75 | 182 | Academic Writing | Science & Tech. | 32.110229 | 95,486,798 |
Effect of pressure on the friction, wear, and surface properties of the transition metals
A study was made of the effect of pressure on the friction, wear, and surface microhardness of some transition metals of Groups V, VI, and VIII sliding under dry friction conditions in a vacuum.
The existence is demonstrated of certain “threshold” pressures at which the frictional force and wear sharply increase. The microhardness of sliding surfaces at first rises and then falls.
The increase in frictional force is attributable to the fact that, with rise in pressure, the type of linkage between the atoms in the sliding surfaces in contact changes. The wear becomes more intense when the zone with a critical dislocation density moves away from the surface with rise in pressure.
KeywordsDislocation Density Surface Property Group Versus Frictional Force Friction Condition
Unable to display preview. Download preview PDF.
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Human-made light sources can alter natural light cycles, causing animals that rely on light cues to make mistakes when moving through their environment. In the journal Frontiers in Ecology and the Environment, a collaboration of ecologists, biologists and biophysicists has now shown that in addition to direct light, cues from polarized light can trigger animal behaviors leading to injury and often death.
Artificial light that occurs at unnatural times or places – often called light pollution – can attract or repulse animals, resulting in increased predation, migrating in the wrong direction, choosing bad nest sites or mates, collisions with artificial structures and reduced time available to spend looking for food, just to name a few. In a classic example, baby sea turtles use the direction of star- and moonlight reflected off the water surface to help them find the ocean when they emerge from their beach nests; in urbanized areas, many turtles turn the wrong way and migrate toward the brighter lights of buildings or streetlamps.
"Environmental cues, such as the intensity of light, that animals use to make decisions occur at different levels of severity in the natural world," explains Bruce Robertson, an ecologist at Michigan State University. "When cues become unnaturally intense, animals can respond unnaturally strongly to them." That heightened response, he says, happens because of the way humans have changed the environment.
In their study, lead author Gabor Horvath, Robertson and their colleagues explain that many animals are also thrown off course by light reflecting from man-made structures. The darker and smoother a surface is, the more highly polarized its reflected light. In most cases, artificial polarized light symbolizes one thing to animals.
"For example, the primary source of horizontally polarized light in nature is water," says Robertson. "Biologists discovered in the 1980s that such polarized light is an amazingly reliable cue for finding bodies of water."
Especially in the case of dragonflies and other insects, which often lay their eggs and spend their first phase of life in ponds, streams and lakes, mistaking human-made objects for water can be deadly. Horizontal, shiny, dark surfaces – such as dark glass surfaces of buildings, asphalt, dark-colored cars and black plastic sheeting – reflect horizontally polarized light that is more strongly polarized than that reflected by water, which augments the animals' attraction to it. Polarized light pollution can disrupt the entire food web in an ecosystem: When insects mistake the sheen of an oil slick for water, their predators often follow the insects to the source and risk becoming trapped and drowning, as in the La Brea tar pits of Los Angeles and other oil-slicked lakes around the world.
Even in the absence of a physical trap, if the attraction is great enough, animals can't remove themselves from a polarized light source, ultimately causing death from dehydration and exhaustion. For example, a dragonfly laying its eggs on a shiny black highway may become paralyzed by attraction to the pavement after laying its eggs, effectively dooming its fate and that of its offspring. These so-called ecological traps occur when environmental change happens more quickly than animals can evolve to react to it. If large numbers of animals fall victim to these false cues, says Robertson, it could cause populations to decline, perhaps to extinction.
There are several ways humans can ameliorate the effects of their overlarge dark, shiny structures. Preliminary studies show that white hatch marks on roads can prevent insects from mistaking them for bodies of water. The addition of white curtains to shiny black buildings, suggests Robertson, also deters insects, bats and birds.
"It's yet another case where we're faced with a choice between what's more expensive or what's better for biodiversity," Robertson says. "Aquatic insects are the foundation of the food web, and what's harmful to them is harmful to entire ecosystems and the services they provide."
Christine Buckley | EurekAlert!
Upcycling of PET Bottles: New Ideas for Resource Cycles in Germany
25.06.2018 | Fraunhofer-Institut für Betriebsfestigkeit und Systemzuverlässigkeit LBF
Dry landscapes can increase disease transmission
20.06.2018 | Forschungsverbund Berlin e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
18.07.2018 | Materials Sciences
18.07.2018 | Life Sciences
18.07.2018 | Health and Medicine | <urn:uuid:810fdf73-0829-46f7-b630-898997414a8d> | 3.671875 | 1,456 | Content Listing | Science & Tech. | 37.714572 | 95,486,815 |
Tributyltin (TBT) is accumulated by all taxa that have been examined. Typical tissue burdens range from undetectable levels to as high as 7 µg g-1 (wet weight). Molluscs, as a group, exhibit the highest tissue burdens and also the highest bioaccumulation factors (BAF). Some microorganisms are also notable accumulators, but in this case adsorption to the biofilm (predominantly polysaccharides) rather than sequestration within cells is an important mechanism of uptake. Crustaceans and fish generally accumulate lower burdens of TBT, probably because they possess enzymatic capability to degrade and excrete TBT. Bioaccumulation factors (BAF) as high as 50 000 have been reported, but the route of uptake (e.g. from water or food) was not necessarily differentiated during the experiment. Experimental studies have specifically examined uptake from water, where calculation of a bioconcentration factor (BCF) is appropriate. BCF values range up to 10 000. Both BAF and BCF values are higher than would be caused by partitioning processes alone. Binding is thus proposed as a mechanism that explains enhanced accumulation. A scheme to explain bioaccumulation is presented that proposes a role for (a) chemical speciation of butyltin with major anions in natural waters, (b) routes of exposure, (c) role for partitioning and binding to control both the kinetics of uptake and burdens in tissues, and (d) contribution of depuration mechanisms to control tissue burdens. Findings presented in this review support the use of biomonitors for TBT contamination, but the tissue burdens of TBT in biomonitors likely reflect a steady-state distribution of TBT in all compartments of the ecosystem rather than concentration in a single compartment (e.g. water). While the topical issue of tributyltin use diminished due to restrictions on its use, this compound provides several important opportunities as a model compound to increase understanding of bioaccumulation processes and environmental compartmentalization, in general. Some further studies may thus be warranted.
Weitere Kapitel dieses Buchs durch Wischen aufrufen
- Bioaccumulation of TBT by Aquatic Organisms
Roy B. Laughlin Jr
- Springer Netherlands
Fallstudie Überschwemmungskarten/© Thaut Images | Fotolia | <urn:uuid:bc2f5e93-62e7-4f63-8099-5a4b34cc0afd> | 2.546875 | 508 | Academic Writing | Science & Tech. | 22.769395 | 95,486,899 |
Tel-Aviv University demos quantum superconductors locked in a magnetic field.
It's called Meisner effect:
Basically, the magnetic field is bent around a superconductor (instead of going through it as in normal metals). So a superconducting magnet can be levitated or suspended on a track of permanent magnets, since it follows the expelled field lines. Also works the other way around, with a permanent magnet on a superconductive surface
Cool demo, in uni we used a supercooled metal ring and electromagnet to make a gun which fired the ring across the lecture theatre.
now that's the stuff we should be doing instead of fighting with another country. Great FIND ! this guy should be getting millions. I think this is the first example of quantum locking i have ever seen...
Science rocks!!!! as usual.....
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Radar meteorological observation
From AMS Glossary
radar meteorological observation
(Or radar weather observation.) An evaluation of the echoes that appear on the display of a weather radar in terms of the orientation, intensity, tendency of intensity, height, movement, and unique characteristics of echoes, which may be indicative of certain types of severe storms (such as hurricanes, tornadoes, or thunderstorms). | <urn:uuid:b8cceba5-f4e9-4668-9224-dafff22f96f1> | 2.859375 | 82 | Structured Data | Science & Tech. | -5.212585 | 95,486,929 |
Methanethiol generation potential from anaerobic degradation of municipal solid waste in landfills
Volatile sulfur compounds are the main odorants at landfills. In this study, methanethiol (CH3SH) was chosen as a typical volatile organic sulfur compound, and its generation potential was investigated during the anaerobic degradation of the organic fractions of municipal solid waste (MSW) including rice, flour food, vegetable, fish and pork, paper, cellulose textile, and yard wastes. Among the experimental wastes, gas generation was the highest in the fish and pork waste with a high CH3SH concentration of up to 2.5% (v/v). Sulfur reduction in the solid phase was mostly converted into gaseous sulfur compounds. During the whole experiment, the cumulative CH3SH generation from the fish and pork waste was 0.139 L kgdw −1, which was about 2 and 6 orders of magnitude higher than that from the other experimental wastes. The ratio of CH3SH-S to TS reduction was 31.56% in the fish and pork waste. These results would be helpful to understand the generation of volatile sulfur compounds during the anaerobic degradation of MSW and develop techniques to control odor pollution at landfills.
KeywordsMunicipal solid waste Landfill Odor Anaerobic degradation of organic waste Methanethiol
This work was financially supported by the National Natural Science Foundation of China with Grants No. 41671245 and No.41371012, Zhejiang Province Key Research Project (2015C03021).
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Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
This slideshow is a short lesson on temperature as affected by the atmosphere and greenhouse gases. The simulation should be used to demonstrate the effect of adding greenhouse gases and clouds. The second slide shows how to calculate the earth’s temperature using the greenhous effect.
Certain types of molecules, “greenhouse gases,” absorb IR and send it back towards earth. Carbon dioxide, H2O are such greenhouse gases, but oxygen and nitrogen are not.
With only part of IR radiation getting out, Earth’s surface temperature rises until
Power in from sun = Power out to space T up from 255 K (0 F) to 285 K (54 F)
Go to PhET’s greenhouse simulation.
Measure temp without greenhouse.
Add greenhouse gas, see effects and experiment with complicated stuff (clouds, etc.).
Powerin= solar power/m2 at earth
* area of sunlight intersected by earth
* fraction of sunlight absorbed by earth
= 1380 W/m2 * πR2earth * 0.7 = = 1.22 x 1017 Watts(!)
Temperature of surface of earth has to be a certain value so that
Power out to space = Power in from sun
Stefan-Boltzmann Law says
Power out to space = 2.89 * 107 W/K4 * T4 * fraction of IR escaping
If greenhouse gases absorb and emit IR such that only 61% of power radiated by earth’s surface gets into space,
Pout = 0.61 * 2.89 * 107 W/K4 * T4.
To conserve energy Pin = Pout, which means T is higher than before.
1.22 * 1017 W = 0.61 * 2.89 * 107 W/K4 * T4, solving for T,
get T = (6.92 * 109)1/4 = sqrt (sqrt(6.92 * 109)) = 288 K.
When the concentration of greenhouse gases goes up, the total power emitted by earth into space
a. goes up. b. goes down. c. stays the same.
Answer: c. stays the same. The atmosphere always has to just balance the amount coming in from sun or earth will rapidly heat up. The effect of greenhouse gases is to block some of the radiation going from the ground to space, so more leaving ground would be necessary to maintain the same amount leaving into space.
power in =
a. Clouds decrease global temperature because they reflect part of sunlight back to space.
b. Clouds increase global temperature because they absorb IR radiation from earth.
c. Clouds increase global temperature because reflected sunlight is then absorbed by the greenhouse gases in the atmosphere.
d. b and c
e. None of the above accurate describe the effect of clouds in the atmosphere. | <urn:uuid:6337936b-6183-45ba-a0b3-e2df5b304389> | 4.09375 | 658 | Tutorial | Science & Tech. | 72.511488 | 95,486,940 |
Volcanism. Any activity that includes the movement of magma towards or onto Earth’s surface. http://dsc.discovery.com/tv-shows/discovery-presents/videos/understanding-volcanoes-lava-flow.htm. Volcano:. A vent or fissure in Earth’s surface through which magma and gases are expelled.
Any activity that includes the movement of magma towards or onto Earth’s surface
A vent or fissure in Earth’s surface through which magma and gases are expelled
Volcanoes are formed by:
An area around the Pacific Ocean characterized by volcanoes and seismic activity
Magma that flows onto the Earth’s surface
Liquid rock produced under the Earth’s surface
This lava flow is smooth, fluid, and “runny” – What type is it…MAFIC or FELSIC?
Just to put the size of the Mount Saint Helens eruption in perspective, this figure compares the size of that eruption (as measured by the volume of ejected material) to some bigger ones in the past. Notice how small Mt. St. Helens was compared to the others!! | <urn:uuid:5c84b339-f789-49dd-8c69-7694b691a3b6> | 3.53125 | 253 | Structured Data | Science & Tech. | 52.144286 | 95,486,951 |
Most of the country, especially northern and Central parts saw a dry June 2018. Additionally, rainfall totals during the next three months are forecast to be generally below normal across the country. Therefore, a short-term drought watch is being issued for central and northern areas of the country. See the map below.
The 12 month SPI-based drought outlook uses data through to May 2018, with potential impacts on large surface water reserves and groundwater. In general negative impacts are expected if the SPI is less than or equal to -1.3 (very dry or worse ref: CDPMN). The current 12-month SPI-based drought outlook for the country shows that there is no long-term drought concern for most of the country except the extreme north where a drought watch is being issued. See the map below.
Forecast Drought Condition for Belize is done using Standardized Precipitation Index (SPI)
The Standardised Precipitation Index (SPI), developed by T.B. Mckee, N.J. Doesken and J. Kleist (McKee et al. 1993) of Colorado State University is an index that, if used carefully, can provide early warning of an extended drought period and aid in assessing drought severity. It can also provide similar information at the other end of the spectrum- extremely high precipitation. SPI is basically a representation of rainfall in units of standard deviation. Positive values indicate greater than median rainfall; negative values indicate less than median rainfall. Belize is now using this tool for early drought warning.
|SPI Value||Category||SPI Value||Impact|
A three-month SPI analysis reflects short to medium term moisture and can give an indication of available moisture conditions at the beginning of the growing season. A six-month SPI analysis reflects medium term trends in rainfall and is effective in showing rainfall distribution over distinct seasons as well as being associated with anomalous stream flows and reservoir levels, which takes longer to manifest itself than does agricultural drought. A twelve-month SPI can indicate the potential periods of shortfall in groundwater amounts.
The information contained herein is provided with the understanding that The National Meteorological Service of Belize makes no warranties, either expressed or implied, concerning the accuracy, completeness, reliability, or suitability of this statement. The information may be used freely by the public with appropriate acknowledgement of its source, but shall not be modified in content and then presented as original material.
If you have inquiries or comments please contact the Climate Section at the National Meteorological Service.
Forecaster: Gordon, Ronald
Last Updated: Fri, Jun 29, 2018 | 11:37 AM | <urn:uuid:ff79a350-359f-42a1-a84c-29778c274e0a> | 3.0625 | 537 | Knowledge Article | Science & Tech. | 39.902239 | 95,486,981 |
Apr 25, 2017 02:03 PM EDT
Engineers from the Massachusetts Institute of Technology have discovered that graphene is able to hold up under high pressure. This strong, ultrathin material may be the solution in making desalination more productive.
A single sheet of graphene is comprised of an atom-thin lattice of carbon which may seem fragile but can withstand applied pressures of at least 100 bars. This is equivalent to about 20 times the pressure produced by a kitchen faucet.
In a post on its official website, MIT reported that the reason why graphene can withstand intense pressures is to pair it with a thin underlying support substrate that has tiny holes or pores. The smaller these pores are, the more resilient the material is under high pressure.
Rohit Karnik, an associate professor in MIT's Department of Mechanical Engineering, said that the study will serve as a guideline for developing tough, graphene-based membranes. This can be used specifically for desalination, where filtration membranes should withstand high-pressure flows to efficiently remove salt from seawater.
It was noted that current existing membranes desalinate water through reverse osmosis. This is when pressure is applied to one side of a membrane containing saltwater and pushes pure water across the membrane while salt as well as other molecules are hindered from filtering through.
Several commercial membranes desalinate water under pressures of about 50 to 80 bars. Anything above that and they tend to get compacted or otherwise suffer in performance.
Using graphene which can withstand pressure of 100 bars or more could lead to more effective desalination of seawater by recovering more fresh water. It is expected to solve the fresh water crisis by having the ability to purify extremely salty water.
The MIT engineers set up experiments to investigate graphene's pressure tolerance. They grew sheets of graphene through a technique named chemical vapor deposition and placed single layers of the material on thin sheets of porous polycarbonate. They discovered that graphene was able to withstand pressures of 100 bars when placed over pores that were 200 nanometers wide or smaller.
See Now: Facebook will use AI to detect users with suicidal thoughts and prevent suicide© 2017 University Herald, All rights reserved. Do not reproduce without permission. | <urn:uuid:f89ba910-e338-42cc-9d46-74d43e2eea49> | 3.890625 | 450 | News Article | Science & Tech. | 30.510648 | 95,487,003 |
Radioactive dating word problems
Some isotopes, however, are unstable and decay radioactively into other elements.
There are many different radioactive isotopes that are used for radiometric dating.
This is a formula which helps you to date a fossil by its carbon.Last year we held a number of meetings on the young/old earth issue and gave YECs numerous opportunities to speak.Andrew Kulikovsky spoke on one occasion and John Hartnett spoke on 2 occasions. About half those who are on the committee are YECs and the others doubt the YEC position to various degrees.The stable form of carbon is carbon 12 and the radioactive isotope carbon 14 decays over time into nitrogen 14 and other particles.Carbon is naturally in all living organisms and is replenished in the tissues by eating other organisms or by breathing air that contains carbon. | <urn:uuid:fd9fe420-bde7-443f-9bf6-9bd4d851c82d> | 3.1875 | 174 | Tutorial | Science & Tech. | 38.087764 | 95,487,027 |
Planes to reroute following massive solar eruption
Published January 23, 2012 | Space.com
A powerful solar eruption is expected to blast a stream of charged particles toward Earth Tuesday, Jan. 24, as the strongest radiation storm since 2005 rages on the sun.
Early this morning (0359 GMT Jan. 23, which corresponds to late Sunday, Jan. 22 at 10:59 p.m. EST), NASA’s Solar Dynamics Observatory caught an extreme ultraviolet flash from a huge eruption on the sun, according to the skywatching website Spaceweather.com.
The solar flare spewed from sunspot 1402, a region of the sun that has become increasingly active lately. Several NASA satellites, including the Solar Dynamics Observatory, the Solar Heliospheric Observatory (SOHO), and the Stereo spacecraft observed the massive sun storm.
A barrage of charged particles triggered by this morning’s solar flare is expected to hit Earth tomorrow at around 9 a.m. EST (1400 GMT), according to experts at the Space Weather Prediction Center, a division of the National Oceanic and Atmospheric Administration. [Video & photos of the huge solar flare]
According to NOAA, this is the strongest solar radiation storm since May 2005, and as a precaution, polar flights on Earth are expected to be re-routed within the next few hours, Kathy Sullivan, deputy administrator of NOAA, said today at the 92nd annual American Meteorological Society meeting in New Orleans, La.
Scientists call these electromagnetic bursts “coronal mass ejections” (CMEs), and they are closely studied because they can produce potentially harmful geomagnetic storms when the charged particles rain down Earth’s magnetic field lines.
In addition to generating stronger than normal displays of Earth’s auroras (also known as the northern and southern lights), geomagnetic storms aimed directly at our planet can also disrupt satellites in orbit, cause widespread communications interference and damage other electronic infrastructures.
“There is little doubt that the cloud is heading in the general direction of Earth,” Spaceweather.com announced in an alert. “A preliminary inspection of SOHO/STEREO imagery suggests that the CME will deliver a strong glancing blow to Earth’s magnetic field on Jan. 24-25 as it sails mostly north of our planet.”
massive solar blast
This still from a NASA space observatory video shows one view of a powerful, M9-class solar storm that unleashed a coronal mass ejection toward Earth in the early hours of Jan. 23, 2012 (GMT).
Sunday’s solar flare was rated an M9-class eruption, which placed it just on the verge of being an X-class flare, the most powerful type of solar storm. M-class sun storms are powerful but mid-range, while C-class flares are weaker.
Last week, a separate sunspot group unleashed several M-class flares, and SDO scientists said these types of flares are occurring almost daily as the sun’s rotation slowly turns the region toward Earth.
The sun’s activity waxes and wanes on an 11-year cycle. Currently, our planet’s nearest star is in the midst of Solar Cycle 24, and activity is expected to ramp up toward solar maximum in 2013. | <urn:uuid:bde1ab77-09b2-4711-bbf1-2703e668662e> | 2.75 | 692 | News Article | Science & Tech. | 47.147636 | 95,487,036 |
Creating an array that holds strings is as simple as writing
[String], but what about creating an array where each item is an array of strings – an array of arrays? This is called a multi-dimensional array, because if you were to draw its contents on paper it would look like a grid rather than a line.
In Swift, creating a multi-dimensional array is just a matter of adding another set of brackets. For example, to turn our
[String] array into an array of arrays, you would just write
[[String]]. But be careful: arrays are value types, which means if you add an array to another array, then modify it, only one of the two copies will be changed.
The code below demonstrates creating an array of arrays, where each inner array holds strings. It also demonstrates the value type situation that might catch you out:
// this is our array of arrays var groups = [[String]]() // we create three simple string arrays for testing var groupA = ["England", "Ireland", "Scotland", "Wales"] var groupB = ["Canada", "Mexico", "United States"] var groupC = ["China", "Japan", "South Korea"] // then add them all to the "groups" array groups.append(groupA) groups.append(groupB) groups.append(groupC) // this will print out the array of arays print("The groups are:", groups) // we now append an item to one of the arrays groups.append("Costa Rica") print("\nAfter adding Costa Rica, the groups are:", groups) // and now print out groupB's contents again print("\nGroup B still contains:", groupB)
print() statement will still print out "Canada, Mexico, United States" because of array's value type behavior: we modified the copy of the array that was inside
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Many meteors streak across the sky, but few explode thunderously the way it did last Thursday in Cyprus. The mysterious outburst baffled and alarmed the locals who felt the ground shake at the force. How common and dangerous is this phenomenon?
The lionfish is a species alien to the Mediterranean Sea, but an increase in sightings has signaled the start of a lionfish invasion. Climate change resulting in warmer water has opened the door to the lionfish threat.
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Many proteins function with partners or as components of a large multiprotein complex. Understanding these interactions is critical to our understanding of biological pathways and cellular function. Discovery of protein:protein interactions is accomplished via several different methods including yeast two hybrid, co-immunoprecipitation and tandem affinity purification (TAP). Using these methods to characterize protein interactions can be a time consuming and difficult process.
Glutathione-S Transferase (GST) pull-down is becoming an increasingly important tool for validation of suspected protein:protein interactions and also for identification of new interacting partners. GST pull-down uses a GST-fusion protein (bait) expressed typically in E.coli and then bound to glutathione (GSH)-coupled particles to affinity purify any proteins (prey) that interact with the bait from a pool of proteins in solution.
Prey proteins can be obtained from multiple sources including cell lysates, purified proteins and cell-free expression systems. Using cell free systems enables the researcher to easily express a variety of prey proteins and map the domain necessary for a successful interaction to occur.
A short animation illustrating this technique can be viewed at: http://www.promega.com/paguide/animation/selector.htm?coreName=tnt01
For examples of using this technique to define required protein domains or for the analysis of the effects of mutations refer to these publications:
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- HaloTag Application: Fluorescence Under Stress - May 11, 2018 | <urn:uuid:fa47f309-20cf-4dda-b420-43a96ae3e672> | 2.796875 | 367 | Knowledge Article | Science & Tech. | 22.965973 | 95,487,042 |
The solution of boundary value problems for partial differential equations is one of the most important fields of applications for integral equations. About a century ago the systematic development of the theory of integral equations was initiated by the treatment of boundary value problems and there has been an ongoing fruitful interaction between these two areas of applied mathematics. It is the aim of this chapter to introduce the main ideas of this field by studying the basic boundary value problems of potential theory. For the sake of simplicity we shall confine our presentation to the case of two and three space dimensions. The extension to more than three dimensions is straightforward. As we shall see, the treatment of the boundary integral equations for the potential theoretic boundary value problems delivers an instructive example for the application of the Fredholm alternative, since both its cases occur in a natural way.
KeywordsHarmonic Function Dirichlet Problem Potential Theory Neumann Problem Continuous Density
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A group of scientists from MSU, Frumkin Institute of Physical Chemistry and Electrochemistry of the Russian Academy of Sciences, and Juelich Research Center described the mechanism of appearance of an inertial lift force acting on finite-sized particles in microchannels. Such calculations were previously possible only for some specific cases. A more accurate description allows one to use this inertial lift for particle sorting. The study was published in Journal of Fluid Mechanics.
The authors of the work studied the forces acting on the particles in microchannels. The behavior of the particles depends on the Reynolds number, which is the ratio of inertial to viscous forces within a liquid. At finite Reynolds number small particles migrate across the streamlines to some equilibrium positions in microchannels. This migration is attributed to the action of inertial lift forces.
Precise calculations of particle migrations in microchannels will help to use them for sorting, e.g. separation of healthy cells from cancerous ones. Since there are several forces simultaneously acting on the particles, their migrations are difficult to interpret theoretically. Previous studies addressed only some simple specific cases, such as the migration of point-like particles, whose size is ignored, or finite-size particles translating in the vicinity of a single wall.
"Inertial microfluidics is widely known and used, but so far only at high Reynolds numbers which is difficult to generate in microchannels since it requires a huge pressure drop to pump the liquid. Therefore modern devices for inertial particle separation employ quite wide channels," explained Evgeny Asmolov, a co-author of the work, senior research associate of Institute of Mechanics, MSU, and leading research associate of IPCE.
The new study proposes a more general theory, which describes a hydrodynamic lift of finite-size particles in microchannels. Besides, the authors succeeded in accounting the particle-wall interaction and analyzing the behavior of particles with different density. If the density of a particle differs from that of a liquid, the lift force will be balanced by gravity and the buoyant force. These two additional forces may shift the equilibrium positions or even cause their disappearance.
The scientists validated the new theory by using computer simulations. According to their results, new formulae turn to obtained earlier in corresponding limiting cases. Moreover, the physicists analyzed several typical experimental settings to predict the behavior of particles.
"According to our predictions, even at low (around ten) Reynolds numbers spherical particles can "take off", by rotating, from the walls of a microchannel, like planes. They then "fly" at certain distances from the walls, which depend only on their density and radius, by forming chains. Remarkably, the "flying altitudes" of such chains will be different even if sizes or densities of constituting them particles differ only slightly. These chains of particles can be easily separated in lab-on-a-chip devices, and the fractionation in this case is more efficient than in wide channels and at high Reynolds numbers," commented Olga Vinogradova, a co-author of the work, professor of the Faculty of Physics, MSU, and head of lab at IPCE. | <urn:uuid:4adcf404-f5d2-4e06-aa2f-b27111ec1d9f> | 2.84375 | 654 | Knowledge Article | Science & Tech. | 24.805329 | 95,487,068 |
Increasing evidence suggests that microbial interactions are important deter- minants of plant biodiversity. The hypothesis that fungal endophyte symbiosis reduces diversity in successional fields was tested by manipulating infection of tall fescue, the most abundant perennial grass in the eastern United States. Over a 4-year period, species richness declined and tall fescue dominance increased in infected plots relative to uninfected plots without differences in total pro- ductivity. A host-specific endophyte, with negligible biomass, altered plant community structure in this long-term field experiment and may be reducing plant diversity throughout its expanding range.
Mendeley saves you time finding and organizing research
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From the Labs: Biotechnology
New publications, experiments and breakthroughs in biotechnology–and what they mean.
A revolutionary technique converts one type of adult cell into another.
Source: “In vivo reprogramming of adult pancreatic exocrine cells to beta-cells”
Douglas Melton et al.
Nature,published online August 27, 2008
Results: By activating a specific set of genes in mice, scientists at the Harvard Stem Cell Institute converted a common type of pancreatic cell into a rarer, insulin-producing one. The research is the first to show that one type of fully formed adult cell can be directly converted into another type.
Why it matters: The technique might ultimately provide a way to replace the cells lost in diabetes and other diseases, such as Parkinson’s and amyotrophic lateral sclerosis (ALS, or Lou Gehrig’s disease). The findings also open a new avenue of research in regenerative medicine–a field in which researchers develop therapies to repair or replace damaged cells and tissue. The technique provides an alternative to generating specific cell types from stem cells and transplanting them. Instead, scientists may be able to grow specialized cells directly from existing tissue in the body.
Methods: The researchers first identified a set of ninegenes that trigger the activity of other genes in pancreatic beta cells. Then they genetically engineered mature exocrine cells, which make up about 95 percent of the pancreas, to express combinations of the nine proteins, called transcription factors, that the genes produce. Eventually, they found a combination of three that transformed the exocrine cells into insulin-producing beta cells.
Next steps: Scientists at Harvard are now trying to repeat the results with human cells. Others are trying a similar approach with different cell types, such as the motor neurons lost in ALS.
Different diseases show specific microRNA profiles in the blood.
Source: “Characterization of microRNAs in serum: a novel class of biomarkers for diagnosis of cancer and other diseases”
Chen-Yu Zhang et al.
Cell Research, published online September 2, 2008
Results: Scientists at Nanjing University in China found that patients with lung cancer, colorectal cancer, and diabetes had characteristic patterns of microRNA circulating in their blood. Each disease was associated with a unique pattern that differed from those seen in healthy people.
Why it matters: The findings provide the basis for a type of diagnostic test that could be more accurate than those currently available. MicroRNAs are small RNA molecules that do not code for proteins but help control protein synthesis. Previous work had shown that they could play some role in cancer. But the new research is the first to find specific microRNA patterns that might be useful for diagnosis. MicroRNAs could also help doctors predict a disease’s progression and evaluate a patient’s responses to treatment. In addition, the study shows that microRNAs might have diagnostic potential for other diseases, such as diabetes.
Methods: Scientists used gene-sequencing technology to identify the type and levels of microRNAs in the blood serum of healthy people and people with lung cancer, colorectal cancer, and diabetes.
Next steps: The researchers are now developing the first commercial diagnostic kit based on measurement of microRNA in blood serum. They aim to release it next year. They are also trying to understand the function of microRNAs in the blood.
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Main image: Data from the Kepler space telescope has been used to find thousands of exoplanets. Credit: NASA
It would be the greatest scientific find in history.
Countless alien worlds have been discovered in recent years – in fact, from a single example in 1992 there are now 3,730 confirmed exoplanets – defined as a planet that orbits another star – on the list. NASA has even launched its Exoplanet Travel Bureau, which explores three of the most Earth-like: Kepler-16b, Kepler-186f, and TRAPPIST-1e.
However, not a single exoplanet has ever been photographed.
Cue Project Blue, which aims to build and launch a space telescope that can image planets situated in the 'habitable zones' of stars in the Alpha Centauri system, the star system closest to us. A habitable zone around a star is the range of orbits far enough away for a planet to support liquid water, which scientists think is a must-have for life to evolve.
If any exoplanet has an atmosphere, or an ocean, this special telescope could photograph them… and could confirm the existence of another Blue Planet similar to our own, which may contain life.
What is Project Blue?
Project Blue is about taking the search for Earth 2.0 from observational astronomy into visual astronomy. While most exoplanets have been discovered using the 'transit' method (a telescope observing a star's light dim slightly as a planet travels across its disk), the future of exoplanet exploration is going to be all about direct observation and photography.
Conceptually, Project Blue is a plan to produce an image to rival two other iconic astronomical images – Apollo 8’s 1968 photo of the Earth-rise around the Moon, and Voyager 1’s ‘Pale Blue Dot’ image from 1990, which Carl Sagan described as showing Earth as ‘a mote of dust suspended in a sunbeam’.
The crowdfunded Project Blue mission (you can donate here), which aims to blast off in the 2021, is the brainchild of the BoldlyGo Institute, Mission Centaur, extraterrestrial life-hunters the SETI Institute, and the University of Massachusetts Lowell.
Which star system will Project Blue look at?
Alpha Centauri, the nearest star system to Earth. “It’s a special place to do exoplanet imaging,” says Dr Jon Morse, CEO and Chair of the Board, BoldlyGo Institute, speaking at the Dawn of Private Space Symposium in June. “It’s also the closest star system to us, by a factor of 2.5 closer than the next Sun-like stars that might have a solar system similar to ours.”
Alpha Centauri is no ordinary solar system. A mere 4.37 light years from us, it consists of three stars: two Sun-sized stars called Alpha Centauri A (also called Rigil Kent) and Alpha Centauri B, and the much smaller Proxima Centauri red dwarf star. In fact, Proxima Centauri is the nearest to us at just 4.24 light years, but despite an Earth-sized exoplanet called Proxima Centauri b being discovered in 2016, Project Blue will ignore it.
While it could be the closest exoplanet to us, there’s a simple reason why Proxima Centauri b is being ignored. “We’re not looking at Proxima Centauri because its habitable zones and the planet that we suspect is there are much too close to the star for us to spatially resolve it,” says Morse. “So we’re focusing on the Sun-like stars Alpha Centauri A and Alpha Centauri B.”
How big is Project Blue's telescope?
It's actually pretty small. "It's as large as it needs to be," says Morse. "Alpha Centauri is special because it’s only 4.37 light-years away, and we only need a 50cm diameter primary mirror in our telescope to spatially resolve the habitable zones."
From low-Earth orbit, this small space telescope will point at Alpha Centauri A and Alpha Centauri B, the two largest stars in the Alpha Centauri system, which are both the same size (give or take) as our Sun. Astronomers already know that Alpha Centauri B has a planet orbiting it, but it's not in the star’s habitable zone. So Project Blue will be on the lookout for new, as yet undiscovered – and, hopefully, blue – exoplanets.
A new era of exoplanet photography
If direct imaging of exoplanets is to be the future of astronomy, some foundational technologies need to be tested first, and that's exactly what Project Blue is intended to do. It will use a disk to block each star's bright surface – thus creating an artificial total solar eclipse – so it can see nearby planets.
But it will also use a technology called active wavefront control to detect very faint reflected starlight – something that even the US$8.8 billion James Webb Space Telescope won’t be able to do. "JWST will have coronagraphs that scientists will use to image Jupiter-class planets around nearby stars, but the JWST coronagraphs won’t have active wavefront control, and so won’t be able to look as close to the stars as we intend to with Project Blue’s coronagraph," says Morse.
The only other mission currently planned to have a coronagraph to image exoplanets is NASA’s WFIRST mission, scheduled to launch around 2025. Future mission concepts that could photograph exoplanets decades from now include Starshade, EXO-C, HabEx and LUVOIR.
Where is Alpha Centauri in the night sky?
The two bright stars of Alpha Centauri appear as a single point of light in the night sky, and it’s mostly visible only from the southern hemisphere. It’s the brightest star in the southern constellation Centaurus the Centaur. In fact, Alpha Centauri and its visually close neighbor, Beta Centauri (which is a whopping 390 light-years from us), point to the Southern Cross.
However, those living below 25 degrees north of the Earth's equator (such as in Florida, North Africa, the UAE, Northern India and Southern China), do sometimes see Alpha Centauri peek above the southern horizon. That explains why this star was worshipped by the ancient Egyptians, who erected temples at Corinth and Delphi that align to the rising of Alpha Centauri.
How long would it take to travel to Alpha Centauri?
It may the closest star system to us, but using current rocket technology it would take about 30,000 years to cross the 40 trillion kilometres (or 4.37 light years, or 1.34 parsecs), between us and Alpha Centauri.
So if we could travel at a tenth of light speed, we could make the trip in about 44 years. Speculative projects include Breakthrough Starshot which would send 1,000 ultra-lightweight nanocraft traveling at a fifth of light speed, and propelling a tiny graphene-shielded spacecraft on the tip of a laser beam; it’s likely, though, that any mission we sent to Alpha Centauri would be overtaken by a mission launched much later but using newer, faster technology.
For the foreseeable future, however, interstellar travel is a slow process, and so the search for Earth 2.0 is likely to remain a purely photographic hunt for many decades to come.
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I have always liked table-top experiments. In my opinion, those who can come up with those ideas really, and I mean really, understand what they are doing. Plus, they usually come up with nice videos (it's funny, now that I think about it, it is mostly fluid dynamics people that get nice videos. Here's one for example).
In the newest issue of Nature, Howard Stone from Harvard has a reeeeeeeeeally cool result. First, let me show you the experimental setup. The tank consists of water at the bottom and then oil on top. The oil (a poor electrical conductor) and the water are connected to electrodes of opposite sign that provide a high voltage. Once everything is turned on, they manually put a drop of water at the top using a pipette.
Initially, the water droplet is attracted towards the upper electrode by dielectrophoretic forces but when the drop actually comes in contact with the top electrode it acquires a positive charge and then it is repelled towards the bottom (the drop is very small and gravity doesn't really play a role here). You would think that when the droplet moves low enough to touch the water reservoir at the bottom it will just merge and become part of the reservoir. It should do that normally, but in this case it should be even better because the drop is positively charged and the water at the bottom is negatively charged and, as we all know, opposite sign charges attract. What's the big deal? Sounds easy enough,right? Well not quite, what Stone and friends found was that the behavior of the droplet actually depends on the voltage applied between electrodes.
When the voltage is low enough, what I quickly described above will happen. But when the voltage is high enough the result is different. Initially, the positively charged droplet moves toward the negatively charged water at the bottom but when they come in contact (just a tiny contact as you can see here) the water in the reservoir transfer negative charge to the droplet and now they will repel. This means the droplet moves up, towards the positively charged electrode that now is creating an electrical attraction between the two. Eventually the drop will touch the upper electrode and again a charge transfer happens, charging the drop positively and therefore the whole cycle repeats. You can watch a video of this "bouncing" here.
Pretty cool, uh?
Burton Richter Dies at 87
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