Month: August 2019

Stress may explain vocal mimicry in Bowerbirds

first_img Citation: Stress may explain vocal mimicry in Bowerbirds (2011, May 11) retrieved 18 August 2019 from https://phys.org/news/2011-05-stress-vocal-mimicry-bowerbirds.html (PhysOrg.com) — Spotted Bowerbirds (Ptilonorhynchus maculatus) are best known for their nests, but these birds are also capable of mimicking the vocalizations of many different species of birds. It was believed bowerbirds were mimicking the sounds of predatory birds as a way of defense, but a new study in Naturwissenschaften determined that is not the case, but rather that stress and stressful situations account for the vocalizations they choose to mimic. © 2010 PhysOrg.com Spotted Bowerbird. Image: Tom Tarrant, via Wikipedia. In attracting mates, male bowerbirds appear to rely on special optical effect More information: * The mimetic repertoire of the spotted bowerbird Ptilonorhynchus maculatus, Laura A. Kelley and Susan D. Healy, Naturwissenschaften, DOI: 10.1007/s00114-011-0794-zAbstractAlthough vocal mimicry in songbirds is well documented, little is known about the function of such mimicry. One possibility is that the mimic produces the vocalisations of predatory or aggressive species to deter potential predators or competitors. Alternatively, these sounds may be learned in error as a result of their acoustic properties such as structural simplicity. We determined the mimetic repertoires of a population of male spotted bowerbirds Ptilonorhynchus maculatus, a species that mimics predatory and aggressive species. Although male mimetic repertoires contained an overabundance of vocalisations produced by species that were generally aggressive, there was also a marked prevalence of mimicry of sounds that are associated with alarm such as predator calls, alarm calls and mobbing calls, irrespective of whether the species being mimicked was aggressive or not. We propose that it may be the alarming context in which these sounds are first heard that may lead both to their acquisition and to their later reproduction. We suggest that enhanced learning capability during acute stress may explain vocal mimicry in many species that mimic sounds associated with alarm.* Vocal mimicry in male bowerbirds: who learns from whom? Laura A. Kelley and Susan D. Healy, Biol. Lett. 23 October 2010 vol. 6 no. 5 626-629 doi: 10.1098/rsbl.2010.0093AbstractVocal mimicry is one of the more striking aspects of avian vocalization and is widespread across songbirds. However, little is known about how mimics acquire heterospecific and environmental sounds. We investigated geographical and individual variation in the mimetic repertoires of males of a proficient mimic, the spotted bowerbird Ptilonorhynchus maculatus. Male bower owners shared more of their mimetic repertoires with neighbouring bower owners than with more distant males. However, interbower distance did not explain variation in the highly repeatable renditions given by bower owners of two commonly mimicked species. From the similarity between model and mimic vocalizations and the patterns of repertoire sharing among males, we suggest that the bowerbirds are learning their mimetic repertoire from heterospecifics and not from each other. 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. Dr. Laura Kelly from the University of St. Andrews led the team of researchers. Kelly has been studying the bowerbirds for some time, and just last year published a study in Biology Letters, “Vocal mimicry in male bowerbirds: who learns from whom?” In this previous study, they looked at different male bowerbirds to determine if the male birds were learning their vocalizations from other male bowerbirds or from the direct species themselves. In studying 19 different male bowerbirds, they found that the males were not learning from other males, but rather directly from other bird species, as each bird mimicked the sounds in slightly different ways. In that study, Kelly believed that finding evidence that the bowerbirds learned from their environment was only the start and planned to find out why they mimic certain birds.This brings us to the recent study published in Naturwissenschaften. While it was believed that these bowerbirds mimicked predators, Kelly and her team found that predator calls accounted for only 20% of the calls the birds had learned. They found the birds were mimicking sounds from “bully” species and aggressive birds, as well as alarms calls from other species.From what the researchers determined, these birds mimic alarm and mobbing calls (sounds birds make when their areas are violated by predators) of the different species in their local environment. They believe the bowerbirds learn these vocalizations under stressed circumstances and later reproduce the sounds when they themselves are stressed. Kelly believes that this is the first study to suggest a possible link between stress and vocal mimicry. Explore furtherlast_img read more

Is it real Physicists propose method to determine if the universe is

first_img More information: Constraints on the Universe as a Numerical Simulation, arXiv:1210.1847 [hep-ph] arxiv.org/abs/1210.1847AbstractObservable consequences of the hypothesis that the observed universe is a numerical simulation performed on a cubic space-time lattice or grid are explored. The simulation scenario is first motivated by extrapolating current trends in computational resource requirements for lattice QCD into the future. Using the historical development of lattice gauge theory technology as a guide, we assume that our universe is an early numerical simulation with unimproved Wilson fermion discretization and investigate potentially-observable consequences. Among the observables that are considered are the muon g-2 and the current differences between determinations of alpha, but the most stringent bound on the inverse lattice spacing of the universe, b^(-1) >~ 10^(11) GeV, is derived from the high-energy cut off of the cosmic ray spectrum. The numerical simulation scenario could reveal itself in the distributions of the highest energy cosmic rays exhibiting a degree of rotational symmetry breaking that reflects the structure of the underlying lattice. Image credit: Hubble/NASA © 2012 Phys.org Explore further (Phys.org)—A common theme of science fiction movies and books is the idea that we’re all living in a simulated universe—that nothing is actually real. This is no trivial pursuit: some of the greatest minds in history, from Plato, to Descartes, have pondered the possibility. Though, none were able to offer proof that such an idea is even possible. Now, a team of physicists working at the University of Bonn have come up with a possible means for providing us with the evidence we are looking for; namely, a measurable way to show that our universe is indeed simulated. They have written a paper describing their idea and have uploaded it to the preprint server arXiv. String theory researchers simulate big-bang on supercomputercenter_img Journal information: arXiv The team’s idea is based on work being done by other scientists who are actively engaged in trying to create simulations of our universe, at least as we understand it. Thus far, such work has shown that to create a simulation of reality, there has to be a three dimensional framework to represent real world objects and processes. With computerized simulations, it’s necessary to create a lattice to account for the distances between virtual objects and to simulate the progression of time. The German team suggests such a lattice could be created based on quantum chromodynamics—theories that describe the nuclear forces that bind subatomic particles. To find evidence that we exist in a simulated world would mean discovering the existence of an underlying lattice construct by finding its end points or edges. In a simulated universe a lattice would, by its nature, impose a limit on the amount of energy that could be represented by energy particles. This means that if our universe is indeed simulated, there ought to be a means of finding that limit. In the observable universe there is a way to measure the energy of quantum particles and to calculate their cutoff point as energy is dispersed due to interactions with microwaves and it could be calculated using current technology. Calculating the cutoff, the researchers suggest, could give credence to the idea that the universe is actually a simulation. Of course, any conclusions resulting from such work would be limited by the possibility that everything we think we understand about quantum chromodynamics, or simulations for that matter, could be flawed. 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: Is it real? Physicists propose method to determine if the universe is a simulation (2012, October 12) retrieved 18 August 2019 from https://phys.org/news/2012-10-real-physicists-method-universe-simulation.htmllast_img read more

Physicist creates math model to predict maximum incremental domino size

first_img Journal information: arXiv A domino can knock over another domino about 1.5x larger than itself. A chain of dominos of increasing size makes a kind of mechanical chain reaction that starts with a tiny push and knocks down an impressively large domino. Original idea by Lorne Whitehead, American Journal of Physics, Vol. 51, page 182 (1983). See http://arxiv.org/abs/physics/0401018 for a sophisticated discussion of the physics. More information: Domino Magnification, arXiv:1301.0615 [physics.pop-ph] arxiv.org/abs/1301.0615AbstractThe conditions are investigated under which a row of increasing dominoes is able to keep tumbling over. The analysis is restricted to the simplest case of frictionless dominoes that only can topple not slide. The model is scale invariant, i.e. dominoes and distance grow in size at a fixed rate, while keeping the aspect ratios of the dominoes constant. The maximal growth rate for which a domino effect exist is determined as a function of the mutual separation.via Arxiv Blog Most everyone has seen dominos in action. Small pitted black planks with white dots on them are placed on their ends next to one another – then at some point, the first is knocked over onto the second. The force of the first falling onto the second causes it to fall, knocking it down onto the third, etc. This continues until all the dominos have been knocked over without any other outside interference. Most domino exhibitions feature planks that are all of the same size, though most intuitively understand that different sizes could be used, which means a smaller domino can knock over one that is larger. But how much larger? That’s the question Leeuwen posed to himself. He turned to math to find the answer and in so doing created a model that predicts not only how much larger a domino can be, but the chain length patterns that would occur using different growth factors.Dominos fall the way they do because when one is stood on end, it possesses potential energy. That energy is released when it is pushed over. But because the force necessary to push the domino over is less than the amount of potential energy stored, it is able to knock over a nearby domino that is larger than it is, a phenomenon known as force amplification.To create a mathematical model, Leeuwen had to remove some real world factors that have an impact on chain reactions that occur when dominos are felled. Real dominos tend to slide at the bottom as they are knocked over, for example, and sometimes when one strikes another the result is an elastic collision that prevents the second domino from falling over. Also, sometimes dominos slide against one another as one strikes another. The result was a model that suggests the largest growth factor in a perfect world is 2, meaning one domino can knock over another that is twice its size.The model also showed how quickly plank size can grow and still allow for a complete chain reaction. Starting with a plank just 10 millimeters high and assuming a growth factor of just 1.7, the model shows the planks growing to a size of the empire state building using just 244 planks. © 2013 Phys.org Explore further Domino Theory: Small steps can lead to big results Successive dominoes. The tilt angle θ is taken with respect to the vertical. Domino 1 hits 0 at the point A. The rotation axis of 1 is the point B and E is that of 0. The normal force f that domino 1 exerts on domino 0 is also indicated. Credit: arXiv:1301.0615 [physics.pop-ph] arxiv.org/abs/1301.0615 (Phys.org)—J. M. J. van Leeuwen, a physicist at Leiden University in The Netherlands has created a mathematical model that predicts the maximum incremental size of falling dominos. He’s found, as he describes in a paper he’s uploaded to the preprint server arXiv, that in a perfect world, the maximum growth factor is approximately 2. Citation: Physicist creates math model to predict maximum incremental domino size (2013, January 11) retrieved 18 August 2019 from https://phys.org/news/2013-01-physicist-math-maximum-incremental-domino.html 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.last_img read more

3in1 device offers alternative to Moores law

first_imgIllustration of the reconfigurable device with three buried gates, which can be used to create n- or p-type regions in a single semiconductor flake. Credit: Dhakras et al. ©2017 IOP Publishing Ltd In the semiconductor industry, there is currently one main strategy for improving the speed and efficiency of devices: scale down the device dimensions in order to fit more transistors onto a computer chip, in accordance with Moore’s law. However, the number of transistors on a computer chip cannot exponentially increase forever, and this is motivating researchers to look for other ways to improve semiconductor technologies. Journal information: Nanotechnology Team engineers oxide semiconductor just single atom thick 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: Prathamesh Dhakras, Pratik Agnihotri, and Ji Ung Lee. “Three fundamental devices in one: a reconfigurable multifunctional device in two-dimensional WSe2.” Nanotechnology. DOI: 10.1088/1361-6528/aa7350center_img Citation: 3-in-1 device offers alternative to Moore’s law (2017, June 14) retrieved 18 August 2019 from https://phys.org/news/2017-06-in-device-alternative-law.html In a new study published in Nanotechnology, a team of researchers at SUNY-Polytechnic Institute in Albany, New York, has suggested that combining multiple functions in a single semiconductor device can improve device functionality and reduce fabrication complexity, thereby providing an alternative to scaling down the device’s dimensions as the only method to improve functionality. To demonstrate, the researchers designed and fabricated a reconfigurable device that can morph into three fundamental semiconductor devices: a p-n diode (which functions as a rectifier, for converting alternating current to direct current), a MOSFET (for switching), and a bipolar junction transistor (or BJT, for current amplification). “We are able to demonstrate the three most important semiconductor devices (p-n diode, MOSFET, and BJT) using a single reconfigurable device,” coauthor Ji Ung Lee at the SUNY-Polytechnic Institute told Phys.org. “While these devices can be fabricated individually in modern semiconductor fabrication facilities, often requiring complex integration schemes if they are to be combined, we can form a single device that can perform the functions of all three devices.”The multifunctional device is made of two-dimensional tungsten diselenide (WSe2), a recently discovered transition metal dichalcogenide semiconductor. This class of materials is promising for electronics applications because the bandgap is tunable by controlling the thickness, and it is a direct bandgap in single layer form. The bandgap is one of the advantages of 2D transition metal dichalcogenides over graphene, which has zero bandgap.In order to integrate multiple functions into a single device, the researchers developed a new doping technique. Since WSe2 is such a new material, until now there has been a lack of doping techniques. Through doping, the researchers could realize properties such as ambipolar conduction, which is the ability to conduct both electrons and holes under different conditions. The doping technique also means that all three of the functionalities are surface-conducting devices, which offers a single, straightforward way of evaluating their performance.”Instead of using traditional semiconductor fabrication techniques that can only form fixed devices, we use gates to dope,” Lee said. “These gates can dynamically change which carriers (electrons or holes) flow through the semiconductor. This ability to change allows the reconfigurable device to perform multiple functions.”In addition to implementing these devices, the reconfigurable device can potentially implement certain logic functions more compactly and efficiently. This is because adding gates, as we have done, can save overall area and enable more efficient computing.”In the future, the researchers plan to further investigate the applications of these multifunctional devices.”We hope to build complex computer circuits with fewer device elements than those using the current semiconductor fabrication process,” Lee said. “This will demonstrate the scalability of our device for the post-CMOS era.” Explore further © 2017 Phys.orglast_img read more

Researchers identify mammals that are most likely to harbor viruses risky to

first_imgPhoto of EcoHealth Alliance PREDICT field technician in Bangladesh holding up Rousettus leschenaultii fruit bat after sampling for viral discovery. Credit: EcoHealth Alliance Scientists know that many of the viral threats we humans will face in the future are likely to come from viruses that already exist but reside in other species, particularly other mammals. The animal hosts have built up some degree of immunity to them, but we have not. Thus, if they jump to us, the result can be devastating. In this new effort, the researchers sought to catalogue all of the known viruses that infect mammals around the globe and identify which are most likely to jump to humans.To create such a catalogue, the researchers created a database that held information on 754 mammal species, which represented 14 percent of all known mammals. They also added approximately 600 known viruses that infect mammals (of which a third were known to jump to humans) and which animals they infect. Next, they created mathematical models to use information in the database to provide useful information regarding the likelihood of a virus jumping to humans.The researchers report that their models suggest that the likelihood of a virus jumping from a mammal species to humans depends heavily on species and geography. Bats were found to carry the largest number of viruses likely to jump to humans and the areas where it was most likely to occur were South and Central America. Primates posed the second largest risk factor, particularly in Central America, Africa and Southwest Asia. Rodents came in third with the risk most pronounced in North and South America and Central Africa. Citation: Researchers identify mammals that are most likely to harbor viruses risky to humans (2017, June 22) retrieved 18 August 2019 from https://phys.org/news/2017-06-mammals-harbor-viruses-risky-humans.html 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. Information gleaned from the system created by the researchers could prove more important over time as more data is added and the risk of a virus jumping rises. The hope is that it can be used to predict the next jump, allowing health officials time to prepare, or perhaps even to prevent it from happening. Cross-species jumps may play unexpectedly big role in virus evolution Photo of mother and baby macaque (Macaca fascicularis) at EcoHealth Alliance PREDICT field site in Thailand. Local person blurred in background and human food on the ground represents human-wildlife contact– a factor that we found to be significant for zoonotic diseases in our global models. Credit: EcoHealth Alliancecenter_img Journal information: Nature More information: Kevin J. Olival et al. Host and viral traits predict zoonotic spillover from mammals, Nature (2017). DOI: 10.1038/nature22975AbstractThe majority of human emerging infectious diseases are zoonotic, with viruses that originate in wild mammals of particular concern (for example, HIV, Ebola and SARS). Understanding patterns of viral diversity in wildlife and determinants of successful cross-species transmission, or spillover, are therefore key goals for pandemic surveillance programs. However, few analytical tools exist to identify which host species are likely to harbour the next human virus, or which viruses can cross species boundaries. Here we conduct a comprehensive analysis of mammalian host–virus relationships and show that both the total number of viruses that infect a given species and the proportion likely to be zoonotic are predictable. After controlling for research effort, the proportion of zoonotic viruses per species is predicted by phylogenetic relatedness to humans, host taxonomy and human population within a species range—which may reflect human–wildlife contact. We demonstrate that bats harbour a significantly higher proportion of zoonotic viruses than all other mammalian orders. We also identify the taxa and geographic regions with the largest estimated number of ‘missing viruses’ and ‘missing zoonoses’ and therefore of highest value for future surveillance. We then show that phylogenetic host breadth and other viral traits are significant predictors of zoonotic potential, providing a novel framework to assess if a newly discovered mammalian virus could infect people. © 2017 Phys.org (Phys.org)—A team of researchers with the EcoHealth Alliance has narrowed down the list of animal species that may harbor viruses likely to jump to humans. In their paper published in the journal Nature, the group outlines the process they used to collect viral data on mammals around the globe, sorted them into groups and listed where they live. James Lloyd-Smith with the University of California offers a News & Views piece on the work done by the team in the same journal issue. Explore furtherlast_img read more

With Delhi on their mind

first_imgInspired by the architechture and design of the city, Shaher – e – Dilli is a series of renderings on Delhi . Through this collection of work the artist is trying to bring to the limelight the referential sketch that serves as a visual diary, a record of an architect’s discovery. There is a certain joy in their creation, which comes from the interaction between the mind and the hand. Our physical and mental interactions with drawings are formative acts. A sketch may serve a number of purposes: it might record something that the artist sees, it might record or develop an idea for later use or it might be used as a quick way of graphically demonstrating an image, idea or principle.What one finds in these sketches are the magic that is hidden in the ruins and the monuments spread all over the city. From quaint corners to tombs every historical landmark of the city is captured in these sketches that have their own fascinating story to share.last_img read more

A tasty affair

first_imgDelhi Cant resist its watering mouth as the most cherished food fantasy comes alive. Paatra – The Indian cuisine restaurant at Jaypee Vasant Continental announces special Kebab promotion An Affair with Kebab.  The fare is a culinary delight for both vegetarians and non-vegetarians with an array succulent kebab cooked perfectly in tandoor. Relish unlimited quantities of five vegetarian and non vegetarian kebabs along with biryani, dal, breads and desserts accompanied by a bucket of beer. The scrumptious kebabs can also be paired with the finest selection of liquor available at Paatra. So head on and order some!Where: Paatra, Jaypee Vasant Continental When: 23 May to 8 June        PRICE: 1699 plus taxes per person TIMINGS: Both Lunch and Dinnerlast_img

More trade fairs needed in Bengal Hakim

first_imgKolkata: State Urban Development and Municipal Affairs minister Firhad Hakim stressed the need for holding more and more trade fairs across the state, for developing the spirit of entrepreneurship among people.”Earlier, there was not much interest in doing business in the state, but people like Chandra Shekhar Ghosh of Bandhan Bank have been great initiators in starting micro industries in the state. If we have more and more such trade fairs, there will be a rise in people-to-people interaction and the spirit of entrepreneurship will develop,” Hakim said at the inaugural ceremony of India International Kolkata Trade Fair (IIKTF) at Karunamoyee Ground in Central Park, Salt Lake. Also Read – Heavy rain hits traffic, flightsThe minister, who was the chief guest at the ceremony, maintained that such platforms are great for initiating link between buyer and seller. “I request Bengal Chamber to initiate classes in entrepreneurship, where young people can come and learn not just about manufacturing products, but also learn how and where to sell them. Our Chief Minister is very supportive of economic activity and we need to develop entrepreneur skills so that the per capita income of Bengal rises with economic growth,” Hakim added. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedIt may be mentioned that this is the first edition of IIKTF. The total number of stalls is 305 and the fair is on from June 1 to 11.”The Bengal Chamber of Commerce & Industry is the oldest and one of the most respected institutions of its kind in India. It is a powerful enabler, lobbying for the development of the economy and Infrastructure in India. The fair was jointly organised by The Bengal Chamber of Commerce & Industry and G S Marketing Associates. The purpose of the trade fair is to promote business and trade around the region. The partner country of IIKTF is Bangladesh and the focus country is Thailand and Sri Lanka this year. The other countries which are participating are Turkey, Egypt, China, Pakistan, Afghanistan, Myanmar and Netherlands”, stated Chandra Shekhar Ghosh, president, Bengal Chamber and chairman and MD, Bandhan Bank.The industry segments whose products are on display and sale include international companies, government departments, furniture and interiors, processed food, lifestyle, health and fitness, electronics, children’s products, auto show etc.last_img read more

Cabinet clears three social security schemes

first_imgThe Union Cabinet on Wednesday gave approval to three mega social security initiatives — one pension and two insurance schemes — to be launched by Prime Minister Narendra Modi on May 9. The schemes — Pradhan Mantri Jeevan Jyoti Bima Yojana (PMJJBY) and Pradhan Mantri Suraksha Bima Yojana (PMSBY) and Atal Pension Yojana (APY)– will be launched in Kolkata, the capital of West Bengal where assembly elections are due next year. “Cabinet approves operationalisation of APY, PMJJBY & PMSBY in all states and UTs,” said a tweet by the PIB. An official release said the decision on APY will benefit 2 crore subscribers in the first year, and that on PMSBY and PMJJBY will provide affordable personal accident and life cover to vast population.last_img

Number of Madhyamik examinees from Bengali medium schools dismal

first_imgKolkata: A study by the West Bengal Board of Secondary Education (WBBSE) has revealed that only a few students have appeared from Bengali medium government and government-aided schools in Kolkata for Madhyamik examination this year.As per reports by WBBSE, there are around 44 schools in the city itself, from which five or less than five students have sat for the Madhyamik examination this year. There are 152 schools in which the number of students who appeared have been found to be 20 or less. Also Read – Rain batters Kolkata, cripples normal lifeThe total number of state and state-aided schools in the city presently stands at 458.”This statistics is a clear pointer that the students are shifting to English medium schools. We have already started English medium in some schools in the city to address this issue,” a senior official of WBBSE said.There was a time when schools like Brahma Boys School and Oriental Seminary were among the top schools in terms of student enrollment. Rabindranath Tagore received his primary education in Brahmo Boys. However, this year only six students from this school had appeared for Madhyamik. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killed”We are not getting enough students even though we have made efforts to bring in students,” said Amit Chandra, principal of Brahmo Boys.The number of students who had appeared from Oriental Seminary stands at 14. A solitary student had sat for the Madhyamik examination from as many as four schools, including Kumar Ashutosh Institution in Paikpara, Bangabasi Collegiate School, Ahiritola School and Sri Vidyamandir Girl’s school.Taltala High School had witnessed two students, while Hindu Academy also had the same number who had appeared for the secondary examination. A board official alleged that recruitment of teachers under political grounds during the Left Front rule is contributing to this trend. A number of primary schools run by the Kolkata Municipal Corporation are also facing similar problems.”We have found out that in some schools the number of students is relatively high, while in others it is distressingly low. We will be forwarding the report to the state Education department, so that necessary steps can be taken to address the issue,” a senior WBBSE official said.last_img read more