(Phys.org) —Two researchers from Arizona State University have found that male chameleons use their color changing abilities for far more than hiding from predators. In their paper published in the journal Royal Society Biology Letters, Russell Ligon and Kevin McGraw describe a study they conducted with captive chameleons that showed that male veiled chameleons use their colors to intimidate other males and that head coloring can predict who might win in a scuffle. Veiled chameleons (Chameleon calyptratus) are native to the Arabian Peninsula — specifically Yemen and Saudi Arabia. Credit: Russell Ligon Explore further When male chameleons challenge each other for territory or a female, their coloring becomes brighter and more intense. During a contest, the lizards show bright yellows, oranges, greens and turquoises. Credit: Russell Ligon Citation: Study shows male chameleons fighting prowess tied to color changing abilities (2013, December 11) retrieved 18 August 2019 from https://phys.org/news/2013-12-male-chameleons-prowess-tied-abilities.html More information: Chameleons communicate with complex colour changes during contests: different body regions convey different information, Published 11 December 2013 DOI: 10.1098/rsbl.2013.0892AbstractMany animals display static coloration (e.g. of feathers or fur) that can serve as a reliable sexual or social signal, but the communication function of rapidly changing colours (as in chameleons and cephalopods) is poorly understood. We used recently developed photographic and mathematical modelling tools to examine how rapid colour changes of veiled chameleons Chamaeleo calyptratus predict aggressive behaviour during male–male competitions. Males that achieved brighter stripe coloration were more likely to approach their opponent, and those that attained brighter head coloration were more likely to win fights; speed of head colour change was also an important predictor of contest outcome. This correlative study represents the first quantification of rapid colour change using organism-specific visual models and provides evidence that the rate of colour change, in addition to maximum display coloration, can be an important component of communication. Interestingly, the body and head locations of the relevant colour signals map onto the behavioural displays given during specific contest stages, with lateral displays from a distance followed by directed, head-on approaches prior to combat, suggesting that different colour change signals may evolve to communicate different information (motivation and fighting ability, respectively).Press release The researchers can’t explain why better or faster head coloring makes for better fighters, but suggest it might indicate higher hormone levels, or perhaps be a simple indicator of a stronger or healthier chameleon.
More information: Banwell, A. F., D. R. MacAyeal, and O. V. Sergienko (2013), Breakup of the Larsen B Ice Shelf triggered by chain reaction drainage of supraglacial lakes, Geophys. Res. Lett., 40, 5872–5876, DOI: 10.1002/2013GL057694AbstractThe explosive disintegration of the Larsen B Ice Shelf poses two unresolved questions: What process (1) set a horizontal fracture spacing sufficiently small to predispose the subsequent ice shelf fragments to capsize and (2) synchronized the widespread drainage of >2750 supraglacial meltwater lakes observed in the days prior to break up? We answer both questions through analysis of the ice shelf’s elastic flexure response to the supraglacial lakes on the ice shelf prior to break up. By expanding the previously articulated role of lakes beyond mere water reservoirs supporting hydrofracture, we show that lake-induced flexural stresses produce a fracture network with appropriate horizontal spacing to induce capsize-driven breakup. The analysis of flexural stresses suggests that drainage of a single lake can cause neighboring lakes to drain, which, in turn, causes farther removed lakes to drain. Such self-stimulating behavior can account for the sudden, widespread appearance of a fracture system capable of driving explosive break up. © 2014 Phys.org Clear view of the Antarctic Peninsula, the Larsen Ice Shelf, and the sea ice covered waters around the region. Credit: NASA When Antarctica’s Larsen B Ice Shelf (once roughly the size of Rhode Island) suddenly collapsed twelve years ago (over a two week period) many blamed global warming—prior to the collapse scientists had observed large stretches of surface water on the shelf, the result of warmer air—it was suggested that the surface water made its way down into crevices causing the shelf to break apart due to pressure from within. In this new effort, the researchers don’t refute the claims of the ultimate cause of the collapse, i.e. global warming, but they do suggest it was a much more complicated process than most have assumed.To gain a better understanding of what might have occurred, the researchers built a computer simulation to emulate the conditions that existed prior to the shelf collapsing. By adjusting multiple variables, the researchers say that it became clear that rather than surface water causing the collapse, it was more likely due to the sudden drainage of just a single lake. When that one lake drained, it caused other lakes nearby to drain, leading to a cascading event that resulted in virtually all of the lakes on the ice shelf draining in a very short period of time. The draining of the lakes led to chaotic stresses all across the shelf causing it to crumble and fall apart. Their theory is bolstered, the team says, by satellite observations just prior to the breakup that showed empty lakes all across the ice shelf.The researchers are unable to explain why the first lake drained, though they suggest it might have been due to a process many years in the making, brought on by global warming. Warmer water under the shelf, for example, may have weekend its structure and perhaps eventually caused a hole to develop in the ice beneath one of the deeper lakes, allowing the lake water to seep through. Lakes discovered beneath Greenland ice sheet 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. Journal information: Geophysical Research Letters Explore further Citation: Research trio offer new explanation for breakup of Larsen B Ice Shelf (2014, January 10) retrieved 18 August 2019 from https://phys.org/news/2014-01-trio-explanation-breakup-larsen-ice.html (Phys.org) —A trio of researchers (two from the University of Chicago, the other from Princeton) has proposed a new theory to explain the sudden breakup of the Larsen B Ice Shelf in 2002. In their paper published in Geophysical Research Letters, Alison Banwell, Douglas MacAyeal and Olga Sergienko suggest that the breakup came about due to the sudden drainage of one surface lake causing others to drain leading to a chain reaction that ultimately led to the entire ice shelf being torn apart.
(Phys.org)—As long as the temperature is above absolute zero, gas molecules are always in constant random motion. They may diffuse—or spread out—through three-dimensional space or, in a process called “surface diffusion,” along the two-dimensional surface of a solid. The most well-known mechanism to explain surface diffusion is a classical mechanism called thermal hopping, in which gas molecules jump from one adsorption site (the place where the gas molecules attach to the surface) to another at a temperature-dependent rate. So far, thermal hopping is the only mechanism known to explain the surface diffusion of hydrogen atoms on the surface of ice. Now in a new study, scientists from Hokkaido University in Japan have reported the first evidence of quantum tunneling as a mechanism for the surface diffusion of hydrogen atoms on the surface of ice, although quantum tunneling has previously been observed for hydrogen atoms on the surface of some metals. In quantum tunneling, the hydrogen atoms can move through barriers that they otherwise could not pass through using only classical mechanisms, such as thermal hopping. “This is the first observation of hydrogen-atom tunneling diffusion on an ice surface,” coauthor Naoki Watanabe, Professor at Hokkaido University, told Phys.org.The new finding means that surface diffusion in this situation may work differently than previously thought. This may have implications for understanding the formation of H2 molecules in interstellar clouds, as the same hydrogen-on-ice surface diffusion process occurs on the surface of cosmic ice just before two hydrogen atoms combine to form an H2 molecule.Since quantum tunneling cannot be observed directly, the scientists had to detect its presence using a creative approach and some high-tech, laser-based analytical tools. In the previous studies on metal surfaces, quantum-tunneling diffusion was detected by taking advantage of the fact that, unlike thermal hopping, quantum tunneling is temperature-independent. Unfortunately, in the ice regime that the scientists investigated here, the temperatures are so low (below 20 K) that the temperature window in which diffusion occurs is too narrow to measure temperature dependence.Instead, the scientists took advantage of an isotope effect. Based on previous experimental data and calculations on thermal hopping and the kinetic energies of gases, the scientists predicted that, at 10 K, hydrogen atoms (which have one proton and one electron) should diffuse at a rate that is 4.5 times faster than that of deuterium atoms (which have one proton, one electron, and one neutron). If the rate difference between the two isotopes were to significantly differ from 4.5 in experiments on ice, then the difference could not be explained by thermal hopping, and would be clear evidence of quantum-tunneling diffusion. Macroscopic quantum phenomena discovered in ice © 2015 Phys.org Explore further As it turned out, the new experimental results showed that, at 10 K, hydrogen atoms diffuse 100 times faster than deuterium ions on a highly ordered type of ice called polycrystalline ice. The researchers concluded that this larger-than-expected kinetic isotope effect can only be explained by quantum tunneling. The researchers also found that, on a less-ordered type of ice called amorphous solid water, the rate difference is about 16, which is only somewhat higher than expected. The scientists believe that this small increase suggests that quantum tunneling may play a role in the surface diffusion on this type of ice, but thermal hopping is likely still the dominant mechanism. The reason why quantum tunneling may be suppressed on amorphous solid water may have to do with its nonperiodic structure, whereas polycrystalline ice has a periodic structure. Another interesting part of the study is the way that the researchers determined the rates—not by direct measurement, but by using two laser techniques called photostimulated desorption (PSD) and resonance-enhanced multiphoton ionization (REMPI). The PSD laser beam first desorbs/detaches the adsorbed gas atoms on the ice surface, and then the REMPI laser ionizes the desorbed atoms. The researchers then measured the ion intensities, which are proportional to the number of desorbed atoms. By comparing the ion intensities of the desorbed hydrogen and deuterium atoms, the scientists could determine the ratio of their concentrations, which in turn could be used to find the ratio of their diffusion rates. As the scientists explained, the results could lead to a better understanding of the astrochemical H2 formation process, and they plan to pursue this area more in the future.”The diffusion mechanism—whether tunneling or thermal hopping—strongly depends on the morphology of the ice surface,” Watanabe said. “Cosmic ice has various ranges of morphology. This work demonstrates how H atoms on cosmic ice diffuse toward H2 formation. The H atoms alternate between tunneling diffusion and thermal hopping until encountering a reaction partner of another H atom. In the future, we would like to continue with similar experiments on heavier atoms such as oxygen and radicals, which also exist on cosmic ice and contribute to the formation of molecules on the cosmic ice.” Illustration of surface diffusion of atoms, with the blue arrows showing quantum-tunneling diffusion (through classical barriers) and the black arrow showing thermal hopping. The figure shows how the diffusion mechanisms differ for (a) low atomic flux (dominated by thermal hopping) and (b) high atomic flux (dominated by quantum tunneling). Credit: Kuwahata, et al. ©2015 American Physical Society Larger-than-expected isotope effect: The PSD-REMPI ion intensities of the deuterium atoms are approximately twice as strong as those of the hydrogen atoms for (a) amorphous solid water and (b) polycrystalline ice at low atomic fluxes. However, the D/H ratio increases with increasing atomic flux by a small amount for (c) amorphous solid water and a larger amount for (d) polycrystalline ice. This large difference in (d) indicates that hydrogen atoms diffuse much faster than deuterium atoms, strongly suggesting that surface diffusion occurs due to quantum tunneling in this ice at higher fluxes. Credit: Kuwahata, et al. ©2015 American Physical Society More information: K. Kuwahata, et al. “Signatures of Quantum-Tunneling Diffusion of Hydrogen Atoms on Water Ice at 10 K.” Physical Review Letters. DOI: 10.1103/PhysRevLett.115.133201 Citation: First observation made of quantum-tunneling diffusion of hydrogen atoms on ice (2015, October 1) retrieved 18 August 2019 from https://phys.org/news/2015-10-quantum-tunneling-diffusion-hydrogen-atoms-ice.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. Journal information: Physical Review Letters
If diamonds are a girl’s best friend, then luxury brands are surely their best acquaintances. The obsession with brands is common to women and men world over. The word ‘brand’ is synonymous with a marquee, which indicates a certain product identity that is well known. A product that is recognised is casually referred to as a brand. Among brands, however, there are categories starting from everyday use products like toilet soap to luxury brands like high-end cars. Also Read – ‘Playing Jojo was emotionally exhausting’Brands may be around us, but often we take them for granted unless of course we have forked out a lot of money to buy a branded product. For example, if we see a luxury car, the first thing that crosses our mind is how much it costs or how expensive it is to maintain. Thus, it is human nature to notice a br and that is associated with an expensive product. This phenomenon is what has propelled the huge demand for luxury brands. Be it an expensive suit or an expensive handbag — the primary object is to flaunt it so that our friends, acquaintances or even passersby notice. Also Read – Leslie doing new comedy special with NetflixOther than a few people I know, most people possess luxury brands that act as an extension of their flamboyant personality. On a derogatory note, such people are called ‘brand wh***s’ as they commonly switch luxury brands just to show off. However, this may be a matter personal choice even if it is considered a vulgar show of money.As the craze for expensive branded product increased over the years, people who could not afford too have begun to aspire for brands. This is something that has been identified by many luxury brand makers. Luxury car makers the world over have diversified into the budget segment to boost their sales. Unlike the 1960s and 70s, when luxury brands were the privy of the super rich, today’s luxury product makers have a wide range of products under the same brand name. This makes it easy for even someone from the upper middle class to buy into a luxury brand. This would have probably been an unfinished dream for his father. Thus today’s generations have it a lot easier than their predecessors thanks to recession-driven economies. As luxury brands are more easily available, their market penetration has increased significantly. Thus brands have come a long way ……Salloli Kumar has been a regular on the page 3 circuit for nearly a decade.
Delhi Photography Club presents their fourth edition of Nicefoto exhibition. As the club explains, this is a one of its kind exhibition for celebrating amateur photography across the world. Nicefoto 2014 will feature photos from over 135 enthusiasts aged between seven years and 67 years from India and around the world. Enthusiasts from as far as China, Netherlands, Australia, Italy, England, Germany, France, Spain, Singapore, USA and Dubai too have sent in their photographs. Delhi Photography Club was setup with the intent of taking photography homes. Also Read – ‘Playing Jojo was emotionally exhausting’The purpose of the DPC is to stimulate, enable, and nurture a fraternity of photography enthusiasts for mutual benefit. Due to fast changing internet and mobile devices space, many more people are consuming photos. They want people to store their memories more beautifully. The club is perhaps the first initiative of this kind in the entire country. To offer situations to practice photography, they do free photo walks every month. For learning the technique, we have workshops for various levels (beginner and intermediate), for motivation, they offer memberships and finally for platform, we have these exhibitions. The club also helps the undeserved children to express themselves creatively through its outreach activities. As a club, we have brought together businessmen, diplomats, doctors, lawyers, homemakers, students and children and helped them in their creative expression using a camera.
Noting that there are several similarities between Varanasi and Kyoto, deputy mayor of the Japanese city Kenichi Ogasawara on Thursday said his country’s government and industries will fully cooperate in the modernisation of the holy city.The Japanese deputy mayor, who reached here on Thursday, held an open meeting with district municipal corporation officials, local MLAs and local corporators to discuss plans for development of the temple town on the lines of Kyoto. Ogasawara’s visit comes in the wake of a Sister City Partnership Agreement signed between Kyoto and Varanasi during prime minister Narendra Modi’s recent visit to Japan.Ogasawara said in a deal between any two cities, works are mostly carried out by Japan’s private industries, but here the Kyoto-Varanasi agreement was signed in front of Indian PM Narendra Modi and his Japanese counterpart Shinzo Abe.
Jaljeera, a refreshing and natural drink, can help to fight intestinal gas and poor digestion, says an expert.Rahul Jain,
Real Madrid and Manchester City qualified for the Champions League knock-out rounds with victories over Paris Saint-Germain and Sevilla respectively.And there was relief at Old Trafford as Manchester United ended a 400-minute wait for a goal to beat CSKA Moscow 1-0 on Tuesday.A fortuitous goal from Nacho proved decisive for 10-time champions Real to win 1-0 despite being outplayed for the majority of the first half of their Group A game at the Santiago Bernabeu. Also Read – A league of his own!PSG were on top throughout the first period with Zlatan Ibrahimovic curling a shot from the left just wide of the far post and Edinson Cavani’s stabbed dink over goalkeeper Keylor Navas cleared off the line by a defender.But the closest they came was Adrien Rabiot’s volley cannoning back off the foot of the post.And when Toni Kroos let fly from distance just after the half hour, the ball spooned up off Thiago Silva and fell to Nacho, who had only come on for injured left-back Marcelo two minutes earlier, inside the area. Also Read – Domingo named new Bangladesh cricket coachPSG goalkeeper Kevin Trapp initially came for the looping ball but as he backtracked from no-man’s land, Nacho’s casual side-foot spun wickedly on the bounce and dropped inside the far post.Little happened in the second half but Angel Di Maria did hit the bar late on with a free-kick, although the French champions couldn’t find the goal their play deserved.Real qualified from Group A thanks to Shakhtar Donetsk romping to a 4-0 win over Malmo, a result which means a win for PSG in either of their last two matches will ensure they join Real in the last 16. City banished memories of their recent Champions League struggles as a confident 3-1 win in Seville qualified them for the last 16 with two games to spare in Group D.Borussia Moenchengladbach’s failure to beat Juventus in Germany, where the sides played out a 1-1 draw, meant City, who now top the group, have made it to the knock-out stages for only the third time.Raheem Sterling set them on their way with a goal after eight minutes while Fernandinho doubled the advantage three minutes later. Frenchman Benoit Tremoulinas gave the Spanish hosts hope but Wilfried Bony’s crisp low finish nine minutes from the break effectively killed the contest, giving City a third straight Group D victory since losing 2-1 at home to Juve in their opening game.In Germany Fabian Johnson gave Borussia the lead on 18 minutes but Stephan Lichtsteiner marked his return from minor heart surgery with the equaliser a minute before the break to restore parity.Juve held on for the final 35 minutes with 10 men after Hernanes was dismissed for a late tackle on Alvaro Dominguez, meaning the Italians need only two more points to go through.City’s neighbours United laboured for long periods despite near total domination against CSKA at Old Trafford before a late Wayne Rooney header snatched a 1-0 win that puts the Red Devils in control of Group B.PSV Eindhoven’s 2-0 win at home to Wolfsburg means United lead those two by a point but a victory over the Dutch outfit at Old Trafford in three weeks time will book the three-time winners’ place in the last 16.United came into the game on the back of three successive 0-0 draws with manager Louis van Gaal’s tactics increasingly coming in for criticism.Urged on by their fans to “attack, attack, attack”, United buzzed around their opponents from the off and enjoyed 70 percent possession but were often let down by their final ball or a poor finish.Just before Rooney scored, goalkeeper David De Gea, a virtual spectator throughout, had to come to his side’s rescue after Ahmed Musa’s perfectly weighted ball sent Seydou Doumbia racing clear.De Gea made a brilliant one-handed save to deny the Ivory Coast forward before the back-tracking Chris Smalling slid in to crucially clear the follow-up off the line.
Kolkata: Following Thursday’s reshuffle order of seven IPS officers, another order bearing reshuffle notice of six IPS officers was published on Friday. In Friday’s order, the earlier posting of Kunal Aggarwal as Special Superintendent (SS), CID Headquarters at Durgapur, was cancelled. On cancellation of his earlier order, Aggarwal has been posted as SS, CID, West Bengal.In Friday’s order, Superintendent of Police (SP), Jhargram, Rathod Amit Kumar Bharat has been posted as Deputy Commissioner of Police (DCP), Zone I (North) in the Howrah Police Commissionerate. The SP of Baruipur Police District, Arijit Sinha, has been made the new SP of Jhargram. The DCP (headquarters) of Howrah Police Commissionerate Ranendranath Banerjee has been posted as DCP, Zone I, Bidhannagar Police Commissionerate, whereas Sukhendu Hira from Bidhannagar Police Commissionerate has been posted as DCP (Headquarters) of Howrah Police Commissionerate. Apart from these, DCP (Headquarters) II of Kolkata Police, Ajay Prasad, has been posted as SP, Baruipur Police District.