‘The way you move’: Body structure brings coordinated movement Citation: Animal communication plays important role in pattern formation (2007, May 8) retrieved 18 August 2019 from https://phys.org/news/2007-05-animal-important-role-pattern-formation.html “People have always been fascinated with the patterns displayed by different animal aggregations, such as milling schools of fish, and flocks of birds that suddenly change direction, and have tried to understand them,” UA researcher Raluca Eftimie explained to PhysOrg.com. “Our mathematical model suggests that if we want to better understand animal group patterns, we should focus on how animals communicate.”In their paper in PNAS, Eftimie and coauthors Gerda de Vries and Mark Lewis explain that, while pattern formation is one of the most studied phenomena of animal groups, current models don’t fully account for the groups’ social interactions, and hence overlook a variety of patterns. The scientists present five models describing how animals may receive communication signals, and discuss how signal reception affects the formation of different patterns, both moving and stationary. In doing so, the scientists’ model not only explains five known group patterns, but also reveals five previously unknown patterns. The scientists also suggest that many more exist.“These patterns were obtained through numerical simulations, and they are particularly important from a mathematical point of view,” Eftimie said. “These types of patterns were not observed with previous mathematical models. That is why this model is so important: by displaying so many patterns, some of them already observed in nature, it actually opens a door to further understanding what causes these patterns.”The scientists’ five animal communication models that influence pattern formation depend on how an animal can receive signals from its neighbors, with the different signals being attractive, repulsive, and alignment forces. As the scientists explain, attractive forces work at long ranges, repulsive forces at short ranges, and alignment forces at intermediate ranges. The five models differ because, for example, not all animals can receive signals from neighbors in front, behind, or moving away from themselves, resulting in different individual reactions and thus different patterns. For instance, in Model M3, animals can only receive signals from individuals in front of them. This means that individuals at the edge of the group that are facing away can leave the group and won’t return, since they don’t receive information from behind. This is called the feathers pattern, and is one of at least three patterns that M3 communication can result in. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Flock of birds. Image credit: US Fish and Wildlife Service. Explore further In an example from another model, M4, individuals can receive signals from other animals ahead or behind—but only if those animals are moving toward the reference individual. In this case, if the individuals in front are moving faster than those behind them, they can lose the group. But later, the group often picks them back up. This behavior can result in expanding and contracting groups called breathers as well as traveling breathers (one of the previously unknown models, and one of at least seven models that M4 behavior can exhibit). The scientists suggest that schools of fish and flocks of birds may use breather behavior as an antipredatory technique.A third interesting example explaining the significance of communication is Model M5, where individuals can only receive signals from animals that are ahead and moving toward them. This behavior, which is seen in Myxobacteria, can manifest in a ripple pattern when two groups approach each other. While a few individuals will continue moving in the same direction, most will turn around due to repulsive forces. This behavior gives the impression that the two waves pass through each other.Because in the different models, different amounts of information are received by an individual, the scientists could also infer that the amount of information received seems to influence the strength of the alignment force required to produce a group pattern. In other words, animals that can receive signals from more directions can align more easily. While a somewhat intuitive concept, this model is the first that has related communication and pattern formation, resulting in the discovery of new models and, more importantly, a path for further investigation.“There are probably many species whose mechanisms of pattern formation are not understood,” Eftimie explained. “But also there are many questions regarding the communication mechanisms these animals use. I think that we are still far from being able to quantify every group pattern. This requires an active collaboration between scientists who construct mathematical models and scientists who can test these models through different biological experiments.” She added that understanding group patterns can lead to some interesting applications, as well.“The study of animal pattern formation has not only theoretical significance, but also some practical applications,” she said. “For example, understanding locust aggregations can help manage and control this species’ outbreaks. Also, understanding schooling behavior can be useful in establishing fishing strategies.”Citation: Eftimie, R., de Vries, G., and Lewis, M. A. “Complex spatial group patterns result from different animal communication mechanisms.” Proceedings of the National Academy of Sciences. April 24, 2007, vol. 104, no. 17.Copyright 2007 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. The way that a flock of birds flies or a school of fish swims may involve more than individuals simply judging the distance between themselves in the group. Recently, scientists from the University of Alberta have shown that a multitude of complex animal patterns can be modeled by accounting for the many ways that different species can communicate with each other.
Via Techradar.comBy: Mary Anne Simpson This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. According to Digital World Tokyo and Techradar.com, a reliable Panasonic source said, “Previous consumer 3D display systems have encountered many different problems, including reduced vertical resolution caused by a 3D display method that divides the scanning lines between the left and the right eyes, and picture quality degradation caused by pixel skipping.” Panasonic has the distinct advantage in this area by putting all of the 3D hoopla on a single Blu-Ray disc. According to Ben Williams of Blu-Ray.com, who witnessed the Panasonic demonstration at CEATEC 2008, “As the demonstration progressed, it was clear that the crowd was witnessing a fully-realized technology and not some one-off publicity stunt.” The demonstration included footage of a team of BMX bikers performing free-style routines. Mr. Williams states, ” I was immediately floored by the depth and realism of the images.” The BMX footage was followed with the Disney movie “Meet the Robinsons” and the blockbuster demonstration of the Opening Ceremony of the Beijing Olympics. Mr. Williams admits prior to this demonstration he was not a big fan of 3D presentations from the old and outdated systems using colored lenses. The difference according to Mr. Williams in the Panasonic technology is the depth of the image. Some of the special effects and gimmickry are still present like placing objects in the foreground to make it appear they are floating, but the plasma screen itself appears to be “several hundred yards deep.” He states the experience was mesmerizing. After the demonstration Mr. Williams spoke with the Panasonic representative who indicated that the new technology probably would require an investment in new hardware. At the same time he did not rule out that technology that is evolving may allow existing displays and Blu-Ray players to be adapted to the technology. In an additional note, Disney has announced that all future animated film from Disney Animation and Pixar will be exhibited theatrically in 3D.The 21st century may be remembered at the beginning of total immersion in film and cinematic expression. Blu-Ray 3D 1080p may be only the beginning of something truly spectacular in visual and audio entertainment for commercial home theater audiences. Citation: Panasonic Unveils 3D 1080p Plasma HDTV On Single Blu-Ray Disc At CEATEC Japan 2008 (2008, October 10) retrieved 18 August 2019 from https://phys.org/news/2008-10-panasonic-unveils-3d-1080p-plasma.html Intel, with Skylake, looks to new day of cable-free computing Panasonic unveiled the latest technology in 3D 1080p on a 100-inch plasma HDTV. According to Panasonic, the 3D innovation was demonstrated at CEATEC Japan 2008 using a Panasonic 100-inch plasma and a Blu-Ray player to deliver full 1080p HD video with separate views to each eye. The infinitesimal differences between the two video streams create the 3D effect in the brain. The Panasonic difference is the ability to create a sustained full high-definition experience. Viewers will need polarized glasses to get the full effect. The old multi-color 3D card board goggles are not necessary which is a good thing. Explore further
Citation: Scientists say dolphins should be treated as non-human persons (2010, January 6) retrieved 18 August 2019 from https://phys.org/news/2010-01-scientists-dolphins-non-human-persons.html (PhysOrg.com)—Scientists studying dolphin behavior have suggested they could be the most intelligent creatures on Earth after humans, saying the size of their brains in relation to body size is larger than that of our closest relatives, the chimpanzees, and their behaviors suggest complex intelligence. One scientist said they should therefore be treated as “non-human persons” and granted rights as individuals. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore further The behavioral studies showed dolphins (especially the bottlenose) have distinct personalities and self-awareness, and they can think about the future. The research also confirmed dolphins have complex social structures, with individuals co-operating to solve difficult problems or to round up shoals of fish to eat, and with new behaviors being passed from one dolphin to another. Several examples of learning being passed on to other individuals have been observed. In one case a rescued dolphin in South Australia, taught to tail-walk during recuperation, in turn taught the trick to other wild dolphins in the Port Adelaide river estuary when she was released. According to marine biologist Mike Bossley it was “like watching a dance craze take off”, with the dolphins apparently learning the trick just for fun, since tail-walking has no natural function.Work carried out by professor of psychology at the City University of New York, Diana Reiss, showed dolphins could recognize themselves in a mirror, and could use it to inspect other parts of their bodies, an ability previously only demonstrated in humans and a few animals such as apes, elephants and pigs. In another study Reiss was able to teach captive dolphins a rudimentary language based on symbols.In anatomical studies of the dolphin, zoologist Lori Marino and colleagues from Emory University, Atlanta, Georgia in the US, used MRI (magnetic resonance imaging) scans to map the brains of dolphins and compare them with the brains of primates. She found the ratio of dolphin brain mass to body size to be second only to the human brain, which means dolphin brains are relatively larger than those of chimpanzees. The neocortex and cerebral cortex of the bottlenose dolphins were particularly large and the cortex had similar convoluted folds to those found in human brains and strongly associated with intelligence. Cortical folds increase the volume of the cortex and its capacity for interconnections to form. Marino said the findings on brain anatomy and intelligence of dolphins mean we should re-examine the treatment of dolphins, especially when their treatment results in suffering.Reiss and Marino say their behavioral and anatomical findings and our new understanding of dolphin intelligence mean it may not be ethical to keep dolphins in aquatic amusement parks for our entertainment, or to kill them for food. Around 300,000 whales, dolphins, and porpoises die each year, with some being killed for food, such as the annual killing of thousands of dolphins and small whales in Taijii, Japan, or even to prove the manhood of those killing them, such as the slaughter of Calderon dolphins at Faroe Island, in Denmark.Reiss and Marino will present their findings at a conference in San Diego, California next month. Also speaking at the conference will be professor of ethics and business at Loyola Marymount University in Los Angeles, Thomas White, who said the new research adds weight to his ideas that dolphins should be regarded as “non-human persons” with the right to be treated as individuals. White is the author of the book “In Defense of Dolphins”. © 2009 PhysOrg.com Group calls for ban on dolphin therapy Credit: CC0 Public Domain
Schematic illustration of a graphene mixer circuit. Image credit: Yu-Ming Lin/Science, 10.1126/science.1204428 (PhysOrg.com) — Taking a giant step forward in the creation and production of graphene based integrated circuits, IBM has announced in Science, the fabrication of a graphene based integrated circuit on a single chip. The demonstration chip, known as a radio frequency “mixer” is capable of producing frequencies up to 10 GHz, and demonstrates that it is possible to overcome the adhesion problems that have stymied researchers efforts in creating graphene based IC’s that can be used in analog applications such as cell phones or more likely military communications. © 2010 PhysOrg.com IBM and others had previously demonstrated that it was possible to create a graphene based transistor; this latest research takes that technology one step further by marrying the transistor and other electronics on a single chip to create a full-fledged integrated circuit.The graphene circuits were started by growing a two or three layer graphene film on a silicon surface which was then heated to 1400°C. The graphene IC was then fabricated by employing top gated, dual fingered graphene FET’s (field-effect transistors) which were then integrated with inductors. The active channels were made by spin-coating the wafer with a thin polymer and then applying a layer of hydrogen silsequioxane. The channels were then carved by e-beam lithography. Next, the excess graphene was removed with an oxygen plasma laser, and then the whole works was cleaned with acetone. The result is an integrated circuit that is less than 1mm2 in total size.The chip produces output signals with mixed frequencies, hence its name, and while the prototype developed is not expected to be used in an actual device, future chips using the new technology are expected to be used in wireless communications. Since a major source of the funding for the research has been provided by the U.S. Defense Advanced Research Projects Agency (DARPA) the first uses of such a chip in an application is likely to be for secretive communications between airborne military pilots; the ultra high frequencies generated make it ideal for such secure applications.Getting the graphene to adhere to other electronic components was by all accounts the most difficult part of the whole process, and apparently took the team, led by Phaedon Avouris, all of a year to accomplish; but it was clearly well worth the effort as research teams the world over continue to search for an eventual replacement to silicon in integrated chips, which by most accounts will hit its limits within the next few years. Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. IBM introduces new graphene transistor More information: Wafer-Scale Graphene Integrated Circuit, Science 10 June 2011: Vol. 332 no. 6035 pp. 1294-1297. DOI: 10.1126/science.1204428ABSTRACTA wafer-scale graphene circuit was demonstrated in which all circuit components, including graphene field-effect transistor and inductors, were monolithically integrated on a single silicon carbide wafer. The integrated circuit operates as a broadband radio-frequency mixer at frequencies up to 10 gigahertz. These graphene circuits exhibit outstanding thermal stability with little reduction in performance (less than 1 decibel) between 300 and 400 kelvin. These results open up possibilities of achieving practical graphene technology with more complex functionality and performance. Citation: IBM creates first graphene based integrated circuit (2011, June 10) retrieved 18 August 2019 from https://phys.org/news/2011-06-ibm-graphene-based-circuit.html
Explore further (PhysOrg.com) — At the end of the Cretaceous period some 65 million years ago, an asteroid slammed into Mexico’s Yucatan Peninsula, causing severe but selective extinction. While that is widely accepted, it has remained unclear exactly what the mechanisms were that caused extinction of ocean-dwelling organisms. Proposed explanations include global darkness due to blocking of sunlight with resulting interruption of photosynthesis at the base of the food chain, deadly radiation due to ozone destruction, global cooling or warming, and ocean acidification). Various widely-accepted hypotheses focus on a collapse of the primary and export productivity in the oceans – such as the so-called Strangelove Ocean or Living Ocean hypotheses, respectively – but do not account for the finding that deep-sea floor dwelling phytoplankton-dependent benthic foraminifera did not undergo significant extinction. Recently, however, research conducted at Universidad Zaragoza in Spain compared benthic foraminiferal records with benthic and bulk stable carbon isotope records. The scientists concluded that decreased productivity was moderate, regional, and insufficient to explain marine mass extinction, suggesting instead that a temporary period of increased surface ocean acidity may have been the primary cause of extinction of calcifying plankton and ammonites, with recovery of primary productivity possibly being as fast in the oceans as on land. Equine herpesvirus study to unravel how virus unlocks immune system ‘gate’ Citation: Not by asteroid alone: Rethinking the Cretaceous mass extinction (2012, January 19) retrieved 18 August 2019 from https://phys.org/news/2012-01-asteroid-rethinking-cretaceous-mass-extinction.html More information: End-Cretaceous marine mass extinction not caused by productivity collapse. Published online before print December 29, 2011, doi: 10.1073/pnas.11106011091 Deep, diverse and definitely different: unique attributes of the world’s largest ecosystem. Biogeosciences, 7, 2851-2899, 2010, doi:10.5194/bg-7-2851-20102 Phytoplankton: below the salt at the global table. Journal of Paleontology, May 1986, v. 60, p. 545-554 Researchers Laia Alegret at Universidad Zaragoza, Ellen Thomas at Yale University, and Kyger C Lohmann at the University of Michigan faced a range of issues in comparing benthic foraminiferal records with benthic and bulk stable carbon isotope records. “One of the main challenges is always to obtain sufficient benthic foraminiferal specimens for a statistically valid analysis,” says Thomas. “In the deep sea, there is no light, and so no photosynthesis. Therefore, almost all food must come from photosynthesis in the surface waters kilometers above – and only a very small percentage of the primary material, produced by unicellular algae, ever reaches the sea bottom.” Put simply, deep-sea benthic foraminifera and other deep-sea organisms1 live in a world where the limiting factor of life is food – because there is extremely little of it.2 This implies that in samples from the deep-sea floor, microscopic shells of the organisms the team studied – foraminifera, a group of unicellular eukaryotes – are dramatically outnumbered by the shells of their relatives that live floating in the sunlit surface waters, and whose shells also fall to the sea floor. “We need to collect at least 300 specimens of the deep-sea dwellers per sample, which takes a lot of time sitting behind the microscope and hand-picking the bottom dwellers from the much more abundant surface dwellers,” Thomas explains to PhysOrg.com. “Then the very highly diverse assemblages need to be sorted out, and all specimens assigned to species.” Thomas also emphasizes that this is complicated by the fact that there is not true international agreement on the taxonomy of these species. The team addressed these issues in a number of ways. “First,” agrees Alegret, “the consistency of our data set is unprecedented: The same authors used the same procedures and the same taxonomic concepts for all sites. Another challenge,” Alegret adds, “was finding microfossils in sediment that is not strongly affected by diagenesis – the high pressure and temperatures that take place during the formation of hard rocks from initially soft clay and ooze, which may strongly affect isotopic results. Material in sediment from scientific ocean drilling sites,” she continues, “is commonly less affected by diagenesis than samples obtained from rocks in quarries and outcrops on land. This gave us good preservation of the calcium carbonate, ensuring accuracy of our isotope results.” This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Thomas notes that the team argues that a collapse of primary productivity by the unicellular algae in the surface waters as proposed in the Strangelove Ocean hypothesis, or continued productivity by such algae but a lack of transport of these algae into the deep bottom waters (also called a collapse of the biological pump) as proposed by the Living Ocean model, would both have resulted in an interruption of food supply to the bottom dwellers for hundreds of thousands of years. “Such an interruption of food supply should have had a serious influence on the bottom dwellers, which in the present oceans react even to changes in the seasonality of food supply. However, we didn’t see that. Rather, the bottom dwellers did not go extinct, indicating that they must have had access to food.”In fact, Alegret notes, in some regions – for example, the Pacific Ocean – there they found an increase in the food supplied to the sea floor – which, she points out, “is incompatible with both the Strangelove Ocean and Living Ocean hypotheses.”The scientists point out that their findings may impact other areas of research, from paleobiology to evaluating the effects of increasing atmospheric levels of carbon dioxide. “In many fields of paleontology it has been accepted that the main cause of such extinction was the collapse of primary productivity,” Thomas notes. “If that is not the case, one needs to look at other factors. If we’re correct in our speculation that a rapid pulse of oceanic acidification can have very severe effects on ocean life, then we need to take that into account when evaluating the potential effects of the very rapid anthropogenic ocean acidification, caused by a different type of acid – specifically, due to high carbon dioxide levels – on ocean life in the near future.”The team is already looking forward to extending their research. However, Thomas cautions, what they’d like to do and what they’ll be able to do depends at least in part on funding. “We’re rather far along with a high resolution analysis of foraminifera and stable isotopes from a site close to one of our studied sites, but in shallower waters.” Once they have these data collected, they can better compare what happened at different depths in the water column in an expansion of their work at different geographic locations. “It would be very exciting,” Thomas envisions, “to test whether we can indeed find direct and quantitative evidence, rather than evidence from extinction patterns of calcifying organisms, for the pH values of the surface waters of the oceans – for example, by trying to apply proxies for oceanic pH and carbonate saturation, such as measuring boron isotopes and/or boron/calcium values in the shells of planktic, or surface-dwelling, and benthic foraminifera across the extinction interval. This is not easy to do,” she points out, “because the planktic – also termed planktonic – foraminifera were so severely affected by the extinction – but it may be possible with the modern possibility to analyze very small amounts of calcite.”“If we want to predict the future effects of the present acidification of the oceans,” Alegret concludes, “we should investigate and understand past acidification events by, for example, comparing the very rapid acidification event triggered by the end-Cretaceous impact 65 million years ago with the much slower acidification during the extreme warming event which occurred 55 million years ago at the end of the Paleocene and caused severe extinction of benthic foraminifera.” Copyright 2012 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Location map and changes in benthic foraminiferal diversity and infaunal morphogroups across the K/Pg boundary. Location of sections and drill sites discussed in the text. (A) Yellow circles indicate a decrease in food flux to the sea floor as estimated from benthic foraminiferal evidence, black circles an increase, and half black circles indicate no significant change. See SI Materials and Methods for construction of map. (B) Blue squares show the decrease in diversity from uppermost Maastrichtian (Cretaceous) to lowermost Danian (Paleogene) for locations shown in A, red triangles show the change in the percentage infaunal taxa, a productivity indicator; data sources are given in SI Materials and Methods. Copyright © PNAS, doi: 10.1073/pnas.1110601109
Operators can reconfigure a virtual network programmatically. Image credit: Nicira This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Citation: Nicira promises virtual networks will transform networking (2012, February 6) retrieved 18 August 2019 from https://phys.org/news/2012-02-nicira-virtual-networks-networking.html Explore further More information: nicira.comvia: Technology Review Fujitsu Develops Technology Employing 10 Gbps Virtual Switch to Substitute for On-Server Virtual Switch Functions Network virtualization could lead to a number of advantages. One of the most important may be its ability to open the doors for cloud computing by eliminating the limitations imposed by the existing network, which cause insecurity and unreliability. Installing the NVP software on servers in a data center essentially provides each application with a private connection to the rest of the Internet, which keeps data more secure. Nicira has also demonstrated that the software can transfer Internet services to another data center without interruption, a move that currently requires all the hardware on the new network to be reprogrammed. This ability could be useful for companies with multiple data centers in different locations, as well as for emergency situations in which a data center loses power.Because the NVP software simplifies network reconfiguration, it enables operators to add new applications in minutes instead of days or weeks. The simplification could also lead to innovative applications that are currently too expensive or technically impossible to produce. Overall, by using virtual networks, Nicira estimates that companies with large data centers could save tens of millions of dollars in infrastructure costs.”Network virtualization is the biggest change to networking in 25 years,” said Stephen Mullaney, Chief Executive Officer of Nicira. “NVP provides the final pivotal piece to cloud computing, the most transformational change to IT in a generation.”The NVP can be deployed on any existing network without the need to change any network hardware, and future changes to the network hardware won’t disrupt the virtual network. NVP only requires an IP address, making the physical network hardware less important. Once installed, the virtual network operates completely independently of the physical network, whose main role is to forward data packets. The company explains that the concept of network virtualization decoupling an application from the network is similar to server virtualization, which decouples an application from the underlying server. Overall, the technology enables the creation of tens of thousands of independent and secure virtual networks.Nicira isn’t the only company pursuing software-defined networking. But it has already raised $50 million in funding from venture capitalists and has several large customers, including AT&T, Deutsche Telekom, Fidelity Investments, eBay, NTT, and Rackspace. The software is commercially available on a monthly subscription-pricing model in which customers pay only for what they use. (PhysOrg.com) — For the past four years, founders of the start-up company Nicira have been developing cutting-edge software that they predict will transform the networking technology underlying the Internet. Today Nicira has debuted the software, called the Network Virtualization Platform (NVP). As its name implies, the NVP software acts as a virtual network by simulating the routers, switches, and other physical hardware used in data center networks. Yet the virtual network is completely independent of the physical network hardware. This software-defined networking means that operators can reconfigure any piece of a network programmatically rather than having to manually reconfigure the physical hardware. © 2011 PhysOrg.com
Citation: Two new species of fish found able to regenerate a lost fin (2012, February 23) retrieved 18 August 2019 from https://phys.org/news/2012-02-species-fish-regenerate-lost-fin.html Journal information: Proceedings of the National Academy of Sciences Explore further (PhysOrg.com) — History has shown that many invertebrates are able to regenerate lost limbs. Rare however, are animals with backbones that are able to do so, and when they do exist, they are usually amphibians or a few species of fish that regenerate parts that are mostly made of skin-like material. Thus the discovery of two species of Polypterus bichir, fish found in Africa, that can regenerate a lost side (pectoral) fin in as little as a month has created some excitement in the scientific community. Such fish are ray-finned, which means their fins are made up of skin-like webbing stretched between bony structures connected directly to the skeleton. Rodrigo Cuervo, a biologist with Veracruz University in Mexico discovered the fish’s unique abilities and has co-written a paper about them with colleagues. They have published the results of their findings in the Proceedings of the National Academy of Sciences. In addition to being a unique find, the discovery suggests that those early fish a long time ago who first hoisted themselves up on land, likely also had such an ability. This is because bichir share traits with both modern amphibians and ancient four-limbed creatures that are known to have walked on land.Scientists don’t know why some animals can regenerate body parts, while others such as humans cannot; they’d really like to of course, because it might lead to a way to cause it to happen when it’s needed. What’s exciting about the bichir discovery is that it means regeneration of limbs that contain real bone is possible and by studying them, researchers might be able to figure out how it is made to happen.Also of interest is how accurate the newly regenerated fins were found to be. Many regenerations are not. In humans for example, when skin is regenerated, it quite often remains noticeable due to the differences between normal skin and scar tissue. The same thing happens when bones are broken and then mend. With the bichir fins, the researchers found that the new ones were almost perfect reproductions of the ones they’d lost. They also found that the fish can also regenerate their tails if lost, though this feature is not nearly as remarkable as the tail doesn’t have bones that are connected to the skeleton. Photo of Polypterus weeksii (mottled bichir). Image: Wikipedia. Fish out of water: Gene clue to evolutionary step More information: Full regeneration of the tribasal Polypterus fin, PNAS, Published online before print February 21, 2012, doi: 10.1073/pnas.1006619109AbstractFull limb regeneration is a property that seems to be restricted to urodele amphibians. Here we found that Polypterus, the most basal living ray-finned fish, regenerates its pectoral lobed fins with a remarkable accuracy. Pectoral Polypterus fins are complex, formed by a well-organized endoskeleton to which the exoskeleton rays are connected. Regeneration initiates with the formation of a blastema similar to that observed in regenerating amphibian limbs. Retinoic acid induces dose-dependent phenotypes ranging from inhibition of regeneration to apparent anterior–posterior duplications. As in all developing tetrapod limbs and regenerating amphibian blastema, Sonic hedgehog is expressed in the posterior mesenchyme during fin regeneration. Hedgehog signaling plays a role in the regeneration and patterning processes: an increase or reduction of fin bony elements results when this signaling is activated or disrupted, respectively. The tail fin also regenerates but, in contrast with pectoral fins, regeneration can resume after release from the arrest caused by hedgehog inhibition. A comparative analysis of fin phenotypes obtained after retinoic acid treatment or altering the hedgehog signaling levels during regeneration allowed us to assign a limb tetrapod equivalent segment to Polypterus fin skeletal structures, thus providing clues to the origin of the autopod. We propose that appendage regeneration was a common property of vertebrates during the fin to limb transition.via ScienceNews © 2011 PhysOrg.com This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
(Phys.org)—Quite often, those people who take care of animals learn over time which are smarter than others. They don’t need to test them, they see it in the way the animals behave. Unfortunately, that’s not very scientific, so evolutionary anthropologists Esther Herrmann and Josep Call have devised a number of challenges for three groups of chimps to see if perhaps a measure of intelligence can be determined for a given species. They have published a report of their findings in Philosophical Transactions of the Royal Society B, one of which is the discovery that one chimp clearly stood out from the rest. Journal information: Philosophical Transactions of the Royal Society B More information: Are there geniuses among the apes? Phil. Trans. R. Soc. B, 5 October 2012 vol. 367 no. 1603 2753-2761 doi: 10.1098/rstb.2012.0191AbstractWe are often asked whether some apes are smarter than others. Here we used two individual-based datasets on cognitive abilities to answer this question and to elucidate the structure of individual differences. We identified some individuals who consistently scored well across multiple tasks, and even one individual who could be classified as exceptional when compared with her conspecifics. However, we found no general intelligence factor. Instead, we detected some clusters of certain abilities, including inferences, learning and perhaps a tool-use and quantities cluster. Thus, apes in general and chimpanzees in particular present a pattern characterized by the existence of some smart animals but no evidence of a general intelligence factor. This conclusion contrasts with previous studies that have found evidence of a g factor in primates. However, those studies have used group-based as opposed to the individual-based data used here, which means that the two sets of analyses are not directly comparable. We advocate an approach based on testing multiple individuals (of multiple species) on multiple tasks that capture cognitive, motivational and temperament factors affecting performance. One of the advantages of this approach is that it may contribute to reconcile the general and domain-specific views on primate intelligence. Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Researches find poop-throwing by chimps is a sign of intelligence The challenges the two came up with for the chimps included such things as finding hidden food, showing them how to do something than seeing if the chimp could emulate it, using a tool to accomplish a task and others related to shape, color or size differentiation. They tested chimps at sanctuaries in Uganda and the Republic of Congo and a third group in a zoo in Germany. In so doing they found that there wasn’t really any one thing that stood out as a hallmark of high intelligence among the groups. Instead, some chimps were found to be really good at some tasks and not so good at others. The one exception was a chimp named Natasha who scored very high on all the tests, leading the researchers to label her exceptional.Those who take care of Natasha have been saying as much all along. She’d become notorious for her antics at the Ngamba Island Chimpanzee Sanctuary, where she resides. She escapes enclosures that hold other apes, at one point using branches to figure out if an electric fence was working. She teases handlers and visitors to the park and sometimes squirts them with water. When asked, all of those who worked with her at the park put her name on the list of the smartest in the group.Pinning down just what exactly high intelligence means however, is not so easy to do. With people, tests have been devised that may or may not be true measures of exceptional intelligence, and as with the chimps, some people who are capable of genius in some areas such as painting, may be average at best in other areas. Thus the term genius has become a loosely defined label if ever there was one. Thus the researchers are hesitant to apply the term to Natasha, despite the fact that she is clearly smarter than any other chimp tested. © 2012 Phys.org Citation: New intellectual testing regimen identifies ‘exceptional’ chimp (2012, August 30) retrieved 18 August 2019 from https://phys.org/news/2012-08-intellectual-regimen-exceptional-chimp.html
Crab Nebula. Credit: NASA © 2016 Phys.org Life’s origins may result from low-energy electron reactions in space Citation: Models suggest cosmic rays can trigger reactions in interstellar ice balls causing formation of more complex molecules (2016, July 5) retrieved 18 August 2019 from https://phys.org/news/2016-07-cosmic-rays-trigger-reactions-interstellar.html (Phys.org)—A team of researchers with affiliations to several universities in the U.S. has found evidence that suggests that cosmic rays striking balls of ice floating around in interstellar clouds can cause the formation of more complex molecules, possibly including those that are believed to be precursors to life. In their paper published in Proceedings of the National Academy of Sciences, the team describes their systematic approach to the study of the ice balls that exist between stars, what they found, and other evidence that supports their ideas. More information: A study of interstellar aldehydes and enols as tracers of a cosmic ray-driven nonequilibrium synthesis of complex organic molecules, PNAS, www.pnas.org/cgi/doi/10.1073/pnas.1604426113AbstractComplex organic molecules such as sugars and amides are ubiquitous in star- and planet-forming regions, but their formation mechanisms have remained largely elusive until now. Here we show in a combined experimental, computational, and astrochemical modeling study that interstellar aldehydes and enols like acetaldehyde (CH3CHO) and vinyl alcohol (C2H3OH) act as key tracers of a cosmic-ray-driven nonequilibrium chemistry leading to complex organics even deep within low-temperature interstellarices at 10 K. Our findings challenge conventional wisdom and define a hitherto poorly characterized reaction class forming complex organic molecules inside interstellar ices before their sublimation in star-forming regions such as SgrB2(N). These processes are of vital importance in initiating a chain of chemical reactions leading eventually to the molecular precursors of biorelevant molecules as planets form in their interstellar nurseries. Cosmic rays are energetic atomic nuclei or other types of particles that travel very rapidly though space, most are believed to be created when supernovas explode. In this new effort, the researchers wondered what might happen when such rays strike bits of ice that float around in interstellar clouds.To begin, the researchers noted that it is believed that space ice-balls are formed when atoms collide with bits of dust made of silicate or other carbon rich material—due to the extreme cold, the atoms adhere to the surface, eventually over time, building up layers of carbon dioxide, water, methane, ammonia and a host of other materials that exist in the cloud. To better understand what happens when cosmic rays strike such ice-balls, the researchers conducted experiments, did some heavy computing and built models to simulate what likely occurs. In so doing, they discovered that the cosmic rays had enough energy to cause the atoms in the ice to bond with one another, forming molecules—even complex organic molecules. Their studies also showed that such reactions were possible even at temperatures as low as -263°C. They suggest their results could answer the question of how biological molecules come to exist on planets, such as Earth.The researchers note that prior research has shown that complex organic molecules do actually exist in interstellar clouds. They also point out that researchers studying data sent back from the Rosetta probe found evidence of organic molecules in a comet, one that is believed to have formed in the Kuiper Belt, an area of space very similar to that used in the models created by the research team. Journal information: Proceedings of the National Academy of Sciences Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Citation: The thermodynamics of learning (2017, February 6) retrieved 18 August 2019 from https://phys.org/news/2017-02-thermodynamics.html Explore further In this model of a neuron, the neuron learns by adjusting the weights of its connections with other neurons. Credit: Goldt et al. ©2017 American Physical Society “The greatest significance of our work is that we bring the second law of thermodynamics to the analysis of neural networks,” Sebastian Goldt at the University of Stuttgart, Germany, told Phys.org. “The second law is a very powerful statement about which transformations are possible—and learning is just a transformation of a neural network at the expense of energy. This makes our results quite general and takes us one step towards understanding the ultimate limits of the efficiency of neural networks.”Goldt and coauthor Udo Seifert have published a paper on their work in a recent issue of Physical Review Letters.Since all brain activity is tied to the firing of billions of neurons, at the neuronal level, the question of “how efficiently can we learn?” becomes the question of “how efficiently can a neuron adjust its output signal in response to the patterns of input signals it receives from other neurons?” As neurons get better at firing in response to certain patterns, the corresponding thoughts are reinforced in our brains, as implied by the adage “fire together, wire together.”In the new study, the scientists showed that learning efficiency is bounded by the total entropy production of a neural network. They demonstrated that, the slower a neuron learns, the less heat and entropy it produces, increasing its efficiency. In light of this finding, the scientists introduced a new measure of learning efficiency based on energy requirements and thermodynamics.As the results are very general, they can be applied to any learning algorithm that does not use feedback, such as those used in artificial neural networks.”Having a thermodynamic perspective on neural networks gives us a new tool to think about their efficiency and gives us a new way to rate their performance,” Goldt said. “Finding the optimal artificial neural network with respect to that rating is an exciting possibility, and also quite a challenge.”In the future, the researchers plan to analyze the efficiency of learning algorithms that do employ feedback, as well as investigate the possibility of experimentally testing the new model.”On the one hand, we are currently researching what thermodynamics can teach us about other learning problems,” Goldt said. “At the same time, we are looking at ways to make our models and hence our results more general. It’s an exciting time to work on neural networks!” More information: Sebastian Goldt and Udo Seifert. “Stochastic Thermodynamics of Learning.” Physical Review Letters. DOI: 10.1103/PhysRevLett.118.010601, Also at arXiv:1611.09428 [cond-mat.stat-mech] Study suggests computational role for neurons that prevent other neurons from firing Journal information: Physical Review Letters © 2017 Phys.org (Phys.org)—While investigating how efficiently the brain can learn new information, physicists have found that, at the neuronal level, learning efficiency is ultimately limited by the laws of thermodynamics—the same principles that limit the efficiency of many other familiar processes. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.