Month: August 2019

Cell phone jammers raise question who controls the airwaves

first_img The jamming technology is not new, but it´s becoming increasingly popular on buses, in restaurants, and in movie theaters. The device works by sending out a powerful radio signal that overwhelms cell phones so that they cannot communicate with cell towers. The gadgets cost around $100 to $1,000 or more, with larger models that can be left on to create a no-call zone.However, using the jammers is illegal in the US, since the radio frequencies used by cellphone carriers are legally protected by the government, similar to the protected frequencies used by television and radio broadcasters. Cell phone companies spend tens of billions of dollars to lease the frequencies from the government, and expect protection from infringement.According to a recent article in the New York Times, the Federal Communication Commission (FCC) warns that people caught using cell phone jammers could be fined up to $11,000 for a first offense. FCC investigators have special technology of their own that can detect the jammers. The commission has already prosecuted several US companies for distributing the devices nationally. While many people find the devices fun as a sort of practical joke, there is also a serious side to the debate. The jammers raise a security threat, since criminals could use them to prevent hostages or others from communicating in an emergency.But in other situations, private businesses have “no cell phone” policies within limited areas to ensure that their employees´ or clients´ concentration is not interrupted. In these places, people shouldn´t be using cell phones in the first place, and the jammers simply enforce that policy.The jammers are currently being sold on sites such as UK-based PhoneJammer.com, which reports its sales have increased by 30% from a year ago to around 400 per month. Holiday sales have exceeded 2,000 of the devices.via: The New York Times Explore further As more people go about chatting obliviously on their cell phones in public places, foreign companies have enjoyed increasing US sales of a new, albeit illegal, device: the cell phone jammer. When you turn it on and slip it in your pocket, the cell phone jammer blocks cell signals within 30 feet. UK rolls out eLoran as GPS backup for safe navigation 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: Cell phone jammers raise question: who controls the airwaves? (2007, November 9) retrieved 18 August 2019 from https://phys.org/news/2007-11-cell-jammers-airwaves.html This cell phone jammer from PhoneJammer.com is marketed as “battery operated, world compatible.”last_img read more

Physicists Show that Correlated Environmental Variations Can Quicken Extinctions

first_img Explore further The passenger pigeon, once the most common bird in North America, was hunted to extinction during the late 1800s and early 1900s. Image: Orthogenetic Evolution in the Pigeons (1920). Why populations go extinct is relatively unknown. Ecologists, biologists, physicists, and other experts have investigated the dynamics of extinctions in an effort to understand the factors involved, which is essential for optimizing conservation management.Recently, a team of physicists has studied how random environmental noise (from a wide variety of factors such as climate and resources) affects how quickly a population goes extinct, which the scientists call the “mean time to extinction” (MTE). Physicists Alex Kamenev and Boris Shklovskii of the University of Minnesota, along with Baruch Meerson of the Hebrew University of Jerusalem, have published their study in a recent issue of Physical Review Letters.As the scientists explained, environmental noise is known to affect a population’s birth and death rates, occasionally decreasing the population size and accelerating its extinction. Earlier theoretical work had assumed that the environmental noise is “white” – that is, random variations of the environment are uncorrelated. But more recently, researchers have found that the real environmental variations are correlated, or “colored” rather than white. “In a broad sense, environmental noise includes irregular variations of environment which are relevant for population dynamics,” Meerson told PhysOrg.com. “For example, temperature variations, droughts, floods, diseases, predators. Were random variations of the environment uncorrelated, they would be describable by the white noise model. The real environmental variations, however, are often correlated. For instance, there is a certain duration of diseases, predators may be present for a certain time, and so on. More often than not, the white noise model should give way to the colored noise model.”Meerson and his coauthors addressed the question of how the color of the environmental noise affects the extinction rate of a population, which has eluded understanding for many years. They found that even relatively weak environmental noise can cause extinctions to occur more rapidly. Generally, the larger a population’s size, the longer it takes a population to become extinct. However, the researchers show that noise color changes this relationship, depending on how long the noise is correlated. Citation: Physicists Show that Correlated Environmental Variations Can Quicken Extinctions (2009, January 13) retrieved 18 August 2019 from https://phys.org/news/2009-01-physicists-environmental-variations-quicken-extinctions.html “The most significant result of this work is that the color of environmental noise may dramatically enhance the population extinction risk,” said Meerson. “Among other surprises was the prediction of the most probable realizations of environmental variations (as reflected in the time-dependence of the birth and death rates) which lead to extinction. It turns out that these vary quite a lot with the noise color.” For a long correlation time of the environmental noise, the population size has almost no effect on the MTE, for a strong enough noise. In this scenario, the population size decreases gradually. The noise color doesn’t directly cause extinction, but it makes a large population fluctuation more probable. In turn, large negative population fluctuations make species more vulnerable to extinction (for instance, because of a temporary drop in fertility), potentially wiping out the population. On the other hand, for a short correlation time of the environmental noise, the MTE changes from scaling exponentially with population size to scaling as a power law. Such short-correlated noise can cause a sudden “catastrophe” in the population, such as by reducing its birth rate to a value that cannot sustain a steady population.Overall, the physicists hope that understanding how correlated environmental variations affect extinction rates will help them understand consequences for ecosystem fragility and species conservation. In the midst of the modern extinction era, understanding the dynamics of extinctions may help humans better realize how we influence natural population changes.More information: Kamenev, Alex; Meerson, Baruch; and Shklovskii, Boris. “How Colored Environmental Noise Affects Population Extinction.” Physical Review Letters 101, 268103 (2008).Copyright 2008 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.center_img As the dust of the election settles, Australia’s wildlife still needs a pathway for recovery (PhysOrg.com) — In general, population extinction is a natural process. For one reason or another, an estimated 99.9% of all species that have lived on Earth are now extinct. However, the reasons for a species going extinct are complex, varied, and changing. Ever since the human population began dispersing throughout the Earth 100,000 years ago, the extinction rate has increased dramatically – as much as 1,000 times, by some estimates – putting us in the midst of a modern extinction called the Holocene extinction event. 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

Infidelity pays off for female Gouldian finches

first_imgMale adult Gouldian Finch. Image: Wikipedia. More information: Females Use Multiple Mating and Genetically Loaded Sperm Competition to Target Compatible Genes, Science 20 August 2010: Vol. 329. no. 5994, pp. 964 – 967. DOI:10.1126/science.1192407 Biologists Sarah Pryke, Lee Rollins and Simon Griffith from Macquarie University in Sydney, Australia, studied the behavior of Gouldian finches (Erythrura gouldiae) in the wild and in captivity to try and find out why females are so willing to be unfaithful to their mates even though if discovered with another male the partner is likely to abandon or reduce his half of the care of the offspring. The males are actively involved both in incubating eggs and finding food for the chicks.With the captive birds Pryke and colleagues separated bond pairs during the mating season by removing the male from for half an hour. While he was absent from the cage they introduced a virgin male, and within a few minutes the male began making advances to the female, and the female responded. There are three genetic variations determining head color in Gouldian finches: one producing a red head, one black, and the other yellow. Black and red-headed birds are genetically incompatible and interbreeding of the two types can produce offspring with low genetic fitness, so the researchers tried various combinations of bird with different head colors. The color of their heads also enabled them to tell which male had fathered the offspring. The scientists also studied the behavior of wild Goudian finches in northern Australia. They are found in tropical areas of northern parts of Western Australia and Queensland, and in the Northern Territory. The Gouldians were once among the most common finches, but are now listed as endangered.The results of the research indicated that if a female mated with a genetically compatible male he could fertilize up to 75 percent of the eggs. Dr Griffith said the female finch seems to be capable of selecting genetically good sperm somehow, to maximize the chances of healthy offspring, adding that “one copulation with good sperm is better than 30 copulations with bad sperm.”The research implies that it would pay most females to be unfaithful at times to insure against infertility or genetic incompatibility in their partners.The next stage of the research will try to determine if the female finch is able to distinguish genetic compatibility in sperm, perhaps by some immune response, or if the more compatible sperm is simply able to penetrate the egg more effectively.The results are published in the journal Science. Explore further © 2010 PhysOrg.com Sons or daughters? Female finches use head colour to decide Citation: Infidelity pays off for female Gouldian finches (2010, August 23) retrieved 18 August 2019 from https://phys.org/news/2010-08-infidelity-female-gouldian-finches.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. (PhysOrg.com) — Females in socially monogamous bird species such as finches often engage in sexual activities with birds outside the pair bond. This is known to benefit males if they produce more offspring, but until now the benefits to the female have been unknown. last_img read more

Physicists devise means for observing single atom interference over coherence length

first_img 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)—Researchers at Sandia National Laboratories in Albuquerque, New Mexico have succeeded in observing the interference of a single atom over a distance far greater than its coherence length using lasers and sequences of light pulses. As they describe in their paper they’ve uploaded to the preprint server arXiv, it’s the first ever such direct observance and opens the door to offering evidence of the existence of non-Newtonian gravity at the micron scale. Explore further Journal information: arXiv Diagram depicting the apparatus for observing a single-atom interferometer. A single atom is trapped in an optical tweezer. The florescence from the atom is coupled to an avalanche photodiode (APD) for detection, showing (bottom left) the two discrete levels of photon counts that are characteristic of collisionally blockaded loading of single atoms into an optical tweezer. A wavepacket trajectory is shown for an atom in free-fall under the influence of gravity and a light pulse atom interferometer sequence. Credit: arXiv:1208.4868v1 [physics.atom-ph] © 2012 Phys.orgcenter_img More information: Observation of Free-Space Single-Atom Matterwave Interference, arXiv:1208.4868v1 [physics.atom-ph] arxiv.org/abs/1208.4868v1We observe matterwave interference of a single cesium atom in free fall. The interferometer is an absolute sensor of acceleration and we show that this technique is sensitive to forces at the level of $3.2times10^{-27}$ N with a spatial resolution at the micron scale. We observe the build up of the interference pattern one atom at a time in an interferometer where the mean path separation extends far beyond the coherence length of the atom. Using the coherence length of the atom wavepacket as a metric, we directly probe the velocity distribution and measure the temperature of a single atom in free fall.via Physics World The research is based on previous work that has shown that a single atom can exist in a state of superposition (where the state of the atom is not known but is believed to exist in more than one at the same time) of two or more routes until a measurement is taken. Because of this it’s possible to record an atom falling taking two different paths due to forces that cause a deviation. To make this come about, the researchers caused a single caesium atom to become isolated after cooling using lasers and magnets. Then they directed the atom to where they wanted it to go using optical tweezers and finally shot it with another laser to cause it to exist in a predefined quantum state. Then, they let gravity take over by turning off the tweezers. As the atom fell, the researches directed pulses of light at it causing it to change its rate of descent; bumping it up or down slightly, creating an environment where two paths could be created. Another laser pulse caused the two paths to overlap at which point the optical tweezers were turned back on allowing for the atom’s quantum state to be measured.To measure the phase shift between the two paths that were created, the whole procedure was repeated several hundred times resulting in a measurement of gravitational forces at work on the atom. By adjusting the lasers the team was able to see a clear pattern of interference emerge, which as it turned out, was 200 times more than the atom’s coherence length. The researchers suggest that because the procedure involves just a single atom, it might be possible to use it to gain further insight into forces that exist between atoms and surfaces that are conductive. They add that with further refinement, i.e. greater precision, it might be possible to show that there exists non-Newtonian gravity at the micron level. Citation: Physicists devise means for observing single atom interference over coherence length (2012, September 11) retrieved 18 August 2019 from https://phys.org/news/2012-09-physicists-atom-coherence-length.html Atom and its quantum mirror imagelast_img read more

Study shows changes in anatomy would have made walking easier without reducing

first_img 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. An international team of researchers has found evidence that suggests evolutionary changes in anatomy would have made walking more economical without reducing utility of muscles for climbing in early hominins. In their paper published in Proceedings of the National Academy of Sciences, the group describes studying bones and fossils from human ancestors and how they fit together to determine their walking and climbing abilities. More information: Elaine E. Kozma et al. Hip extensor mechanics and the evolution of walking and climbing capabilities in humans, apes, and fossil hominins, Proceedings of the National Academy of Sciences (2018). DOI: 10.1073/pnas.1715120115AbstractThe evolutionary emergence of humans’ remarkably economical walking gait remains a focus of research and debate, but experimentally validated approaches linking locomotor capability to postcranial anatomy are limited. In this study, we integrated 3D morphometrics of hominoid pelvic shape with experimental measurements of hip kinematics and kinetics during walking and climbing, hamstring activity, and passive range of hip extension in humans, apes, and other primates to assess arboreal–terrestrial trade-offs in ischium morphology among living taxa. We show that hamstring-powered hip extension during habitual walking and climbing in living apes and humans is strongly predicted, and likely constrained, by the relative length and orientation of the ischium. Ape pelves permit greater extensor moments at the hip, enhancing climbing capability, but limit their range of hip extension, resulting in a crouched gait. Human pelves reduce hip extensor moments but permit a greater degree of hip extension, which greatly improves walking economy (i.e., distance traveled/energy consumed). Applying these results to fossil pelves suggests that early hominins differed from both humans and extant apes in having an economical walking gait without sacrificing climbing capability. Ardipithecus was capable of nearly human-like hip extension during bipedal walking, but retained the capacity for powerful, ape-like hip extension during vertical climbing. Hip extension capability was essentially human-like in Australopithecus afarensis and Australopithecus africanus, suggesting an economical walking gait but reduced mechanical advantage for powered hip extension during climbing. Explore further Why aren’t humans ‘knuckle-walkers?’ Journal information: Proceedings of the National Academy of Sciencescenter_img How and when early human ancestors first began walking upright remains a topic of debate among scientists, and research continues to find the answer. In this new effort, the researchers took another look at conventional ideas suggesting that the first hominins to walk upright likely did so extremely awkwardly, as they retained physical features that would allow them to escape enemies by climbing trees. The researchers suggested that if that were the case, those early hominins would not have survived.To prove their theory, they began by taking a closer look at human gait and comparing the data with how apes and monkeys walk. They noted that the angle at which the leg and hip bones meet are different between the species, which means that walking upright for apes and monkeys places a lot of stress on thigh muscles, hamstrings and the knees. A shorter ischium (curved bone at the base of the pelvis) in humans allows for full extension without undue pressure on other leg parts. The net result, the researchers noted, is an ability to walk not only upright, but more efficiently.The researchers then looked at the anatomy of ancient hominins—going all the way back to Lucy. All of the members of Australopithecus, they noted, had a full range of motion, allowing them to walk upright—even as they conserved traits that allowed them to climb much better than today’s humans. The researchers also found that an older hominin known as Ardi, who lived approximately 4.4 million years ago, had pelvic anatomy that allowed for walking upright almost as easily as modern humans, yet still had a long ischium. This, the team claims, shows that early hominins were able to walk upright and climb trees in relatively easy fashion—not clumsily, as others have suggested. © 2018 Phys.org Evolved changes in pelvis shape allow the hamstrings muscles (red) to hyper-extend the hip in humans, but not in apes. Credit: PNAS Citation: Study shows changes in anatomy would have made walking easier without reducing muscles for climbing in early hominins (2018, April 3) retrieved 18 August 2019 from https://phys.org/news/2018-04-anatomy-easier-muscles-climbing-early.htmllast_img read more

No business like show business

first_imgImaan Imaan Paani (We are Drowning) inspired by Salvador Dali’s The Persistence of Memory and Edvard Munch’s The Scream was directed by Dr. Mrinal Jyoti Goswami and performed by the Bhaxa Xahityo Xonmiloni, Axom, Assam in Assamese, Rabha, Bodo and Gibberish.Imaan Imaan Paani, is the name of a game played by children in Assam, during a phase when they are still untouched by the turbulence of life.Purushasukta (Based on Apourusheya) is written by Dr. J. Sreenivasa Murthy and was directed by Joseph John. Also Read – ‘Playing Jojo was emotionally exhausting’Purushasukta is the most popular hymn found in all Vedas and used in almost any ritual. The hymn speaks about the Supreme Being – the Purusha, who pervades all that we know and beyond. This world is seen as a small part of that Purusha, and is constantly changing for it is created and destroyed at every moment. Purushasukta is an open-ended, multi-lingual play in which mantras have been used in their various traditional chanting forms and translations have been interwoven into the play. Also Read – Leslie doing new comedy special with NetflixAlka, the play performed by the Little Thespian from West Bengal has been written by Manoj Mitra and directed by Uma Jhunjhunwala.Alka is a social play which throws light on different aspects of life. On one hand it shows the worries of Alka, the mother, and on the other hand there is Mansi, her docile daughter who having once being a victim of domestic violence due to dowry, rises like a phoenix and tries to bring her perpetrators to justice.There was also a Nautanki performance by the Braj Kala group. The play revolves around how the fourteen day absence of Amar Singh Rathore, general of Shah Jahan’s rajputani battalion, after taking permission for the absence of only seven days, is used by other interested parties to sow the seeds of discord and bitterness between the Mughals and the Rajputs.last_img read more

Mark of novelty

first_imgThe show has participation of more than 101 veteran as well as young and emerging artistes from all over India. Some of the veteran artistes among them are – RK Yadav, Niren Sen Gupta, Jagadish Dey, Sangeeta Gupta, Badal Chitrakar and Vijender Sharma. Karun Tokas, Monica Wadhwa, Amrita Sharma, Priya Chowdhari, Daya Chand, Paramesh Paul, Neha Mulki, Ram Omkar and Tabassum Zaidi are some of emerging master artists whose works viewers can enjoy at the show. Also Read – ‘Playing Jojo was emotionally exhausting’This edition will be divided into four groups, based on the innovative idea of displaying art works in rotation to maintain novelty all through the duration of the show.  It is a distinguishing feature of The Lexicon Art Show where  though artworks keep changing but continuity is maintained. The 16-day long show has 4 groups of 4 days each. All these groups will showcase a different set of paintings and sculptures from different artists. Such an arrangement ensures that fresheners of the show are vibrant and the viewers enjoy the novelty during each session till the end. In terms of business also, all the previous shows proved quite fruitful. This is a format where appreciation and sales are quite guaranteed for the artists. When: On till 21 SeptemberWhere: Ambience Mall, GurgaonTiming: 11 am onwardslast_img read more

Autorickshaw driver heckles female passenger in Jadavpur

first_imgKolkata: An auto-rickshaw driver allegedly heckled a woman when she was taking her son to school at Jadavpur on Monday morning.Police said that the woman had gone to take an auto-rickshaw along with her son, who is a class IV student. She was in a hurry as she had to drop her son at the school on time as he had an examination on Monday.The woman told the police that the auto-rickshaw driver was waiting to get more passengers, which was getting them late. Apprehending that they may not be able to reach school on time, the woman left the auto-rickshaw finding that a bus of 1A route was approaching. Also Read – Rain batters Kolkata, cripples normal lifeThe woman ran to take the bus but she missed it and had to return to take the auto-rickshaw to reach the school.The woman alleged that the driver of the auto-rickshaw, identified as Ashok, didn’t allow the woman to get inside the vehicle and pushed her. He also allegedly passed lewd comments at the woman in front of her son.The situation turned worse when he also attempted to ensure that the woman is not allowed to travel in anyother auto-rickshaws available there. The woman had no idea that she would be heckled by the auto-rickshaw driver if she returned to the vehicle after failing to get the bus. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedIt has been learnt that the woman told the police that she had left the auto-rickshaw to get the bus only because she was in a hurry as she had to take her son to school on time. But she never thought that such an incident would be the consequence.The woman lodged a complaint against the driver with the police. The police have initiated a probe in this connection and initiated a search for the driver.The police are also taking necessary steps to check recurrence of such incidents in the city.last_img read more

Inspired by the Silk route

first_imgWeaving a story of heritage, China’s Gansu opera house recently showcased a performance inspired by the ancient silk route. The troupe staged a performance that showcased their martial arts and sword wielding prowess. The group, from Dunhuang, used traditional instruments like Pipa and Guzheng in the performance. Talking about the highlight of the show, Peng Deming, the art director of the show said, “The main highlight of the show is that it has been prepared with Dunhuang and the Silk Road in the backdrop. Added to this we have specially prepared two Indian songs to express our love and respect for India.”Talking about his experience in India Deming said, “This is my first visit to India and people have been very cooperative with us. They have supported us in every big and small thing.” The troupe has performed in 20 countries, Peng said that the group has been warmly received everywhere,” I personally feel that art, music and dance are the common languages of the world. Maybe we have different artistic methods to express but we all are one. Our attempt is to link the world with our performance and to display our culture, music, tradition and diversity.”last_img read more

Women who prefer dominant partners more at risk of crime

first_imgWomen who prefer physically formidable and dominant mates (PPFDM) have a tendency to feel more at risk of crime regardless of the situation or risk factors present, suggests a new research. The research showed that women who are attracted to dominant men generally feel more at risk of being victimised, even when their risk of victimisation is actually low.PPFDM appears to be associated with women’s self-assessed vulnerability. Women with strong PPFDM feel relatively more at risk, fearful, and vulnerable to criminal victimisation compared to their counterparts, regardless of whether there are situational risk factors present, explained the researchers. Also Read – ‘Playing Jojo was emotionally exhausting’“Our research suggests that the relationship between feelings of vulnerability, as measured by fear of crime, and women’s preference for physically formidable and dominant mates is stable, and does not update according to environmental circumstances or relative level of protection needed,” said Hannah Ryder, researcher from the University of Leicester in Britain.Further, women’s fear of crime significantly changed in response to crime signals —for example location and time of day —and that overall fear of crime was related to PPFDM. Also Read – Leslie doing new comedy special with NetflixHowever, the relationship between PPFDM and fear did not vary in relation to risk situation, perpetrator gender, or crime type, suggesting that the psychological mechanisms underlying the relationship between perceived risk of victimisation and PPFDM are general in nature.The study, published in the journal Evolution and Human Behaviour, involved assessing whether the relationship between fear of crime and PPFDM was higher for crimes that cause relatively higher physical and psychological pain, such as sexual assault.Across two studies in the lab and field, women observed images and real life situations that varied in the risk of crime, such as crime hotspots and safespots, and were asked to rate their perceived risk of victimisation — a measure of fear of crime.This included— male and female —perpetrated physical assault and robbery and male-perpetrated rape. In both studies, the research team also administered a scale that measured women’s PPFDM, and assessed the association between women’s PPFDM score and their risk perception scores.last_img read more

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