Month: August 2019

first_img Journal information: Biology Letters 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. Mourning cuttlefish are not actually fish, they are more closely related to squid and octopus, and like them they can not only shoot ink into the water to make a hasty escape from predators, but can change the coloring of their skin at will. Up until now, researchers had assumed the coloring changes were used only to help the cuttlefish hide from predators passing by. After witnessing one specimen change his coloring on just one side of his body to mask his presence from a rival male while simultaneously displaying different coloring on the other, the team looked a little deeper, studying pictures and video of the cuttlefish taken over time of cuttlefish that lived in Sydney Harbor and discovered something that had been missed before; males displaying split-down-the-middle coloring when trying to mate with a female while at the same time, hiding that fact from other males in the area. This video shows tactical deception employed in the mesocosm. Rival males are to the right of screen. This research was published in the journal Biology Letters in the paper: It pays to cheat: tactical deception in a cephalopod social signalling system by Culum Brown, Martin P. Garwood and Jane E. Williamson. It doesn’t work every time of course as sometimes the rivals catch on, which generally results in a fight; something cuttlefish want to avoid because sometimes another rival can sneak in while two others are otherwise engaged and make the whole bout moot.The researchers say the deceptive ploy by the male cuttlefish is yet another instance of intelligence and that the males are smart enough to employ the technique only when it has a fair chance of working. Thus, if more than two males (or multiple females) are around, they don’t even bother. The fact that the behavior is so directed indicates the cuttlefish are aware of what they are doing, which shows that some sort of thinking is going on. Being cephalopods, cuttlefish are members of one the smartest groups of creatures that live under the sea, with bigger brains relative to body size than any other invertebrate. They’re also very social. Some have been seen to bond with schools of fish when separated from their own kind. © 2012 Phys.org Image: Macquarie University (Phys.org) — Researchers in Australia have discovered that mourning cuttlefish (Sepia plangon) have the unique property of being able to change the coloring on one side of their body to mimic the coloring of a female to fool rivals, while displaying typically male coloring on the side that a nearby female sees; all at the same time. The team, led by Culum Brown at Macquarie University first noticed the sly behavior in a large test tank. Subsequent research showed that the ploy was prevalent in the wild as well. The team has had their paper describing their findings published in the journal Biology Letters. More information: It pays to cheat: tactical deception in a cephalopod social signalling system, Biology Letters, Published online before print July 4, 2012, doi: 10.1098/rsbl.2012.0435AbstractSignals in intraspecific communication should be inherently honest; otherwise the system is prone to collapse. Theory predicts, however, that honest signalling systems are susceptible to invasion by cheats, the extent of which is largely mediated by fear of reprisal. Cuttlefish facultatively change their shape and colour, an ability that evolved to avoid predators and capture prey. Here, we show that this ability is tactically employed by male mourning cuttlefish (Sepia plangon) to mislead conspecifics during courtship in a specific social context amenable to cheating 39 per cent of the time, while it was never employed in other social contexts. Males deceive rival males by displaying male courtship patterns to receptive females on one side of the body, and simultaneously displaying female patterns to a single rival male on the other, thus preventing the rival from disrupting courtship. The use of tactical deception in such a complex communication network indicates that sociality has played a key role in the cognitive evolution of cephalopods. Citation: Researchers discover cuttlefish able to mimic female on half its body (w/ Video) (2012, July 4) retrieved 18 August 2019 from https://phys.org/news/2012-07-cuttlefish-mimic-female-body-video.html Cuttlefish have high definition polarization vision, researchers discover Explore furtherlast_img read more

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first_img Journal information: Physical Review Letters Citation: Magnetic shell provides unprecedented control of magnetic fields (2013, January 4) retrieved 18 August 2019 from https://phys.org/news/2013-01-magnetic-shell-unprecedented-fields.html Magnetic shells can be used to increase the magnetic energy of multiple magnets: The four magnetic dipoles in (a) interact very weakly, even when they are moved closer together in (b). However, when all four dipoles are surrounded by a shell as in (c), their exterior fields become enhanced, yielding a stronger magnetic field in the center region. Credit: Carles Navau, et al. ©2012 American Physical Society Explore further The newly designed magnetic shell can either expel or concentrate magnetic energy. In the left panels, a small dipole magnet in (a) is surrounded by a magnetic shell in (b), which expels its magnetic energy further outward. In (c), a second shell harvests the energy and concentrates it into its center hole; in this way, magnetic energy is transferred through empty space. In the right panels, two dipole magnets in (d) are surrounded by shells in (e) that expel their magnetic energy. As shown in (f), the result is magnetic coupling between the two dipoles. Credit: Carles Navau, et al. ©2012 American Physical Society The physicists, Carles Navau, Jordi Prat-Camps, and Alvaro Sanchez at the Autonomous University of Barcelona in Spain, have published their results on their new method of magnetic energy distribution and concentration in a recent issue of Physical Review Letters.”We have tried with this work to open new ways of shaping magnetic fields in space,” Sanchez told Phys.org. “Since magnetic fields are so crucial for so many technologies (e.g., almost 100% of the energy generated uses magnetic fields), finding these new possibilities may bring benefits.”The basis of the technique lies in transformation optics, a field that deals with the control of electromagnetic waves and involves metamaterials and invisibility cloaks. While researchers have usually focused on using transformation optics ideas to control light, here the researchers applied the same ideas to control magnetic fields by designing a magnetic shell with specific electromagnetic properties. The shell can be used to control magnetic fields in two ways, depending on its location relative to a magnetic source. When a magnetic source is placed inside the shell, the shell expels the magnetic energy outside. When the shell is placed near a magnetic source located outside the shell, the shell harvests and concentrates the magnetic energy from the source into a hole in the shell’s center. For practical purposes, this approximation is sufficient to work for a variety of potential applications, in which the magnetic shell’s two functions (transferring and concentrating) can be used together or independently. For instance, by surrounding two magnetic dipoles with their own shells, the magnetic coupling between them can be enhanced, which could be used to improve the efficiency of wireless power transmission between a source and a receiver.With its ability to concentrate nearby magnetic fields, a single magnetic shell could also be used to increase the sensitivity of magnetic sensors. The scientists demonstrated that a magnetic sensor placed inside the shell can detect a much larger magnetic flux from an external magnetic source than it would when using a typical concentration strategy involving superconductors. Magnetic sensors are often used in consumer electronics, factory automation, navigation, and many other areas. The magnetic shell could also have medical applications, such as for biosensors that measure the brain’s response in magnetoencephalography, a technique used for mapping brain activity. The physicists also showed that the shells can be used to surround multiple magnetic sources arranged in a circle, allowing them to concentrate magnetic energy in the center of the circle. This arrangement could be used in transcranial magnetic stimulation (TMS), a technique used to treat psychiatric disorders. While TMS generally targets regions near the brain’s surface, the magnetic shells could help extend the reach of magnetic fields to deeper targets.Magnetic energy also plays a vital role in power applications, such as in power plants, magnetic memories, and motors. All of these applications require magnetic energy to be spatially distributed or concentrated in a certain way. By enabling the control of magnetic energy in new ways, the magnetic shells could improve these applications and others due to their many possible configurations.”We are presently working on extending these ideas of applying transformation optics to the magnetic case into different directions, and see how future designs can be implemented in practice (in the present case, we suggested superconductors and ferromagnetic materials as a practical implementation of the magnetic shell),” Sanchez said. Complexity in core-shell nanomagnets 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. More information: Carles Navau, et al. “Magnetic Energy Harvesting and Concentration at a Distance by Transformation Optics.” PRL 109, 263903 (2012). DOI: 10.1103/PhysRevLett.109.263903 Copyright 2013 Phys.org All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of Phys.org. In both cases, the shell works by dividing the space into an exterior and interior zone and then transferring the magnetic energy completely into one domain or the other. This method differs from the way that superconductors and ferromagnets distribute magnetic energy, where the energy always returns to the domain where the magnetic sources are.Although no material exists that can perfectly meet the requirements for the magnetic shell’s properties, the physicists showed that they could closely approximate these properties by using wedges of alternating superconducting and ferromagnetic materials. (Phys.org)—A general property of magnetic fields is that they decay with the distance from their magnetic source. But in a new study, physicists have shown that surrounding a magnetic source with a magnetic shell can enhance the magnetic field as it moves away from the source, allowing magnetic energy to be transferred to a distant location through empty space. By reversing this technique, the scientists showed that the transferred magnetic energy can be captured by a second magnetic shell located some distance away from the first shell. The second shell can then concentrate the captured magnetic energy into a small interior region. The achievement represents an unprecedented ability to transport and concentrate magnetic energy, and could have applications in the wireless transmission of energy, medical techniques, and other areas.last_img read more

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first_img Explore further (Phys.org) —Scientists have a great deal of evidence to support the fact that the universe contains much more baryonic matter than baryonic anti-matter, a phenomenon known as baryon asymmetry. Baryons, which are defined as being made of three quarks, include protons and neutrons and make up the bulk of the atomic matter that we’re familiar with in everyday life. But much less is known about the possibility of a lepton asymmetry, in which there are unequal amounts of leptons and anti-leptons in the universe. The best known examples of leptons are electrons and neutrinos. Neutrinos in particular are much harder to detect than baryons because they’re much lighter, and so much less energetic. Citation: Observations of early universe hint at a giant excess of anti-neutrinos (2013, March 21) retrieved 18 August 2019 from https://phys.org/news/2013-03-early-universe-hint-giant-excess.html More information: Dominik J. Schwarz and Maik Stuke. “Does the CMB prefer a leptonic Universe?” New Journal of Physics. 15 (2013) 033021. DOI: 10.1088/1367-2630/15/3/033021 Journal information: New Journal of Physics 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.center_img Copyright 2013 Phys.org All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of Phys.org. Nine year WMAP image of background cosmic radiation (2012) Credit: NASA Could dark baryons explain dark matter? In a new study, physicists Dominik J. Schwarz and Maik Stuke at Bielefeld University in Germany have published a paper in the New Journal of Physics in which they show that recent data from cosmic microwave background (CMB) experiments suggests that the universe contains an excess of anti-neutrinos (defined by their opposite chirality rather than opposite charge) compared with normal neutrinos. Further, this lepton asymmetry could potentially exceed the baryon asymmetry, which is 10-10, by several orders of magnitude. The total number of leptons could also exceed the total number of baryons in the universe.”A ‘leptonic universe’ is a universe that contains many more leptons than baryons,” Schwarz told Phys.org. “A universe with a vast amount of anti-neutrinos in it would be something unexpected. I can’t say how it would change the overall picture, as we are just at the beginning to explore this idea.”Finding evidence for a lepton asymmetry is not easy. For one thing, leptons have such low energy that large numbers of them can easily hide in the neutrino background and escape scientists’ attempts to detect them. But, as Schwarz and Stuke explain, leptons could be observable in the early universe because they would have affected nucleosynthesis (the production of nuclei that occurred just a few moments after the Big Bang) and the CMB (the radiation left over from the photon decoupling that occurred when the universe was about 400,000 years old).In particular, leptons would have affected the production of helium in the early universe. In this study, the physicists measured the abundance of primordial helium in the universe using new CMB data from three sources: the Atacama Cosmology Telescope, the Southpole Telescope, and the WMAP Team. By comparing the results of this global analysis with previous results of helium abundance from local observations of extragalactic regions, the scientists could put some constraints on lepton asymmetry. The data indicated that we may live in a universe ruled by anti-neutrinos instead of normal ones, which could have implications for how we currently understand what happened in the early universe. In addition, the anti-neutrino surplus would theoretically lead to an increase in the expansion rate of the universe. However, the data so far does not rule out the standard scenario of Big Bang nucleosynthesis. “With regard to Big Bang Nucleosynthesis, [confirmed lepton asymmetry] would certainly falsify the standard scenario, which assumes that there is no lepton asymmetry,” Schwarz said. “However, the new model for nucleosynthesis would not be radically different; it would just incorporate this new ingredient.”In the future, the physicists hope that upcoming CMB data releases and improved measurements of primordial abundances will allow for further testing of lepton asymmetry. “I think it would be surprising if the asymmetry in leptons turns out to be much larger than the asymmetry in baryons,” Schwarz said. “Although in some sense, we should honestly admit that we don’t know how the matter anti-matter asymmetry comes along. Thus we should not be surprised but rather open-minded.”last_img read more

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first_img © 2015 Phys.org 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. In other news, Steven Dick, an astronomer with ties to the Library of Congress, stirred interest in and out of the science community by openly asking the question: How would the world change if we found extraterrestrial life? Scientists would be thrilled of course, he notes, but how would everyone else react? Seems reasonable to ponder the implications since we are trying so hard to find it. Meanwhile another team of deep thinkers has been looking into how countries treat one another when oil is at stake and their study showed that crude conspiracy theories could be right—the need for energy does appear to be a justification for some countries interfering with the running of other countries. And while it might be difficult to find a good use for it, a combined team of chemists from the U.S. and Australia found a way to unboil eggs—at least the whites. The work is actually part of learning how to pull apart tangled proteins and letting them refold, which could have a big impact on the medical and food industries. Also a team of researchers in the U.S. found a higher dementia risk can be linked to more use of common medications and a group of paleontologists unearthed a long-necked “dragon” in China—it is actually a dinosaur, of course.And finally, if you are a Craigslist user you might be interested in knowing that a team of researchers at the University of Minnesota recently uncovered a connection between Craigslist personal ads and HIV trends. They do not attempt to explain why the advent of Craigslist has led to a 15.9 percent increase in reported HIV cases, but the assumption seems to be that the site promotes risky hookups. Citation: Best of Last Week – Popper’s experiment realized again, unboiling eggs and the connection between Craigslist and HIV (2015, February 2) retrieved 18 August 2019 from https://phys.org/news/2015-02-week-popper-unboiling-eggs-craigslist.html Explore furthercenter_img A ‘Fermi surface’ is kind of three-dimensional map representing the collective energy states of electrons in a material. These computer-generated illustrations show how the Fermi surface for CeRhIn5 changes, depending upon whether the electrons are strongly interacting (left) or weakly interacting (right). Credit: Q. Si/Rice University and J.X. Zhu/Los Alamos National Laboratory (Phys.org)—It was an interesting week for physics as Popper’s experiment was realized again, by a different team this time, using a different approach, causing physicists to wonder what it actually means because the results still do not violate the uncertainty principle. Also in an international effort, a team found that evidence is mounting for quantum criticality theory which suggests that some odd electronic behavior can be attributable to quantum fluctuations of strongly correlated electrons. Another team at the University of California used the idea of a quantum computer as a detector to show that space is not squeezed—confirming the assumption, based on the theory of special relativity, that space looks the same in all directions. Research uncovers connection between Craigslist personals, HIV trendslast_img read more

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first_imgBlooming Tree school, Janakpuri celebrated its fifth Annual Day with great fervour on December 21 at Dr. Sarvapalli Radhakrishnan Auditorium, Delhi Cantonment. The function commenced with Ganesh Vandana and lighting of the lamp by the chief guest and eminent educationist, Lata Vaidyanathan, Former Principal, Modern School, Barakhamba Road, Member, Governing Body of CBSE and Director of Teri Prakriti School, Gurgaon.250 students aged between 2 to 4 years performed at the event, which was a colourful extravaganza of music, dance and drama with foot tapping music and enthralling dance sequences. The children looked resplendent in their colourful costumes. The musical production titled Joy Ride was a story about a boy who never stopped dreaming and whose dream was finally fulfilled. The play concluded with the words of Walt Disney that ‘Dreams do come true for those who have the courage to pursue them’. The chief guest and parents were overwhelmed by the mesmerizing performances of the children. The children were given a standing ovation by the audience. Parents and grandparents lauded the efforts of the staff and students.last_img read more

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first_imgDelhi Police Commissioner B S Bassi on Friday hinted that Congress MP Shashi Tharoor will be questioned “soon” by the Special Investigation Team (SIT) which is probing the mysterious death case of his wife Sunanda Pushkar.“I think in the next couple of days, all the key persons who have to be questioned by us will be questioned. We would like to complete it soon. I think the SIT will soon do it,” he told reporters here today outside Police Headquarters when asked when would Tharoor be questioned in the case. He also denied reports that the viscera samples which are almost one-year-old must have been spoilt by now and would not reveal the kind of poison that caused Sunanda’s death even if it is sent abroad.last_img read more

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