Desert Snake Hears Mouse Footsteps with its Jaw

first_img However, snakes do have an inner ear and a cochlea, and scientists have observed the animals react to auditory stimuli. But exactly how snakes hear without external ears is still unclear. In a new study, physicists Paul Friedel and J. Leo van Hemmen from the Technische Universitat Munchen in Germany and biologist Bruce Young from Washburn University in Kansas have presented a model of how the horned desert viper Cerastes cerastes hears – with its jaws.While the jaw-hearing method is widely known, the new research uses naval engineering techniques to explain how vibrations from the jaw travel through the head and give rise to sounds in the animal’s brain. The scientists also explain one of the more intriguing parts of jaw-hearing, which is that the snake’s left and right sides of its jaw can move independently in order to localize a sound’s source, such as the location of a mouse’s footsteps.“Up to now, no one has ever pondered the fact that snakes could use jaw-hearing in stereo,” Friedel told PhysOrg.com. “This is, however, crucial, since stereo hearing is essential for locating a sound source. We have thus explained how jaw-hearing can actually be very informative for the snake, and not simply a system signifying that ‘something is there.’”As a mouse skitters across the desert sand, its footsteps create surface waves (specifically, Raleigh waves) with a wavelength of about 15 centimeters and amplitude of the order of 1 micrometer. These surface waves are similar to water waves, in the sense that the sand particles (modeled as a continuous medium) carry out an elliptic motion. The wave velocity of the ripples is about 45 meters per second. The frequency of the waves peaks between 200 and 1000 Hz – which falls squarely into the snake’s optimal sensitivity for frequencies of around 300 Hz. When the horned desert viper has its jaw resting on the sand, the vibrations from the mouse footsteps pass underneath both sides of the jaw. The vibrations travel through the snake’s head through two bones – the quadrate and stapes – and then stimulate the cochlea. The snake’s auditory system can sense jaw movement down to angstrom-sized motions (on the order of a single atom). The scientists determined that the lower jaw amplitude is about half that of the 1-micrometer incoming surface wave – plenty large enough for the snake ear to detect with efficiency. Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Bats evolved diverse skull shapes due to echolocation, diet Just a few decades ago, some scientists doubted that snakes could hear at all. Snakes lack an outer ear and external ear openings, making it difficult to understand how the reptiles receive acoustic vibrations.center_img Citation: Desert Snake Hears Mouse Footsteps with its Jaw (2008, February 13) retrieved 18 August 2019 from https://phys.org/news/2008-02-snake-mouse-footsteps-jaw.html The horned desert viper rests its head on the sand to listen for prey. A sand surface wave moves the left and right sides of the jaw independently, and the vibrations travel to the quadrate, stapes and inner ear. Image source: Friedel, et al. From the cochlea, the auditory signals are relayed along axonal delay lines to a set of topographically organized map neurons in the brain. The researchers modeled this neuronal network, where every map neuron is tuned with microsecond accuracy to a specific “interaural time difference,” or the time difference between signals received from the left and right sides of the jaw. When a map neuron fires, it corresponds to a specific input direction, enabling the snake to localize its prey with stereo precision.The hearing model gives strong support to snakes’ unusual way of hearing, showing that the technique is not only possible, but is also a highly efficient survival mechanism. As Friedel explains, the jaw-hearing method offers some advantages compared with the conventional hearing method using outer ears.“This has to do with the so-called impedance matching problem,” he said. “If air-born sound arrives at a tissue surface, most of the energy will be reflected. This is because the acoustic impedance (which is a measure of how ‘easily a sound wave can be generated’) of air is much smaller than that of tissue (or the inner ear). To solve this problem, the mammalian middle ear possesses three hearing ossicles that transfer the sound from the tympanic membrane through the inner ear. The snake does not have a middle ear with three ossicles, but by using the jaw-quadrate-stapes pathway, the problem of impedance matching is avoided.”More information: Friedel, Paul, Young, Bruce A., and van Hemmen, J. Leo. “Auditory Localization of Ground-Borne Vibrations in Snakes.” Physical Review Letters, 100, 048701 (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.last_img read more

Scientists discover fractal pattern in Scotch tape

first_img Copyright 2010 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. The findings could help scientists better understand the cause of the X-rays generated from peeled tape, which is thought to be associated with the surface roughness of the tape. Information about the tape’s surface roughness could also be used to explain the maximum emitted photon energy of the tape.The scientists also suggested that, by understanding the tape’s surface roughness after peeling, manufacturers could build in a specific roughness during the production process that could stabilize the adhesion, resulting in tape that can be used multiple times without losing its adhesive properties. Peeling at low velocity results in a rough surface, while peeling at high velocity results in a smoother surface. Scientists found that both surfaces exhibit unexpected fractal scaling properties. Image credit: B. N. J Persson, et al. (PhysOrg.com) — Clear cellophane tape – which can be found in almost every home in the industrialized world – may seem quite ordinary, but recent research has shown otherwise. In 2008, scientists discovered that, when peeled, Scotch tape produces X-rays that are strong enough to image the bones in a human finger. In a new study, scientists have further investigated what happens when clear tape is peeled, and found that the tape’s surface roughness displays a fractal pattern. The findings may lead to a better understanding of the processes involved in peeling, the origin of the X-ray emission, and in the design of better tape that can be reused repeatedly. Citation: Scientists discover fractal pattern in Scotch tape (2010, December 9) retrieved 18 August 2019 from https://phys.org/news/2010-12-scientists-fractal-pattern-scotch-tape.html These images show the surface profiles of the adhesive side of peeled tape, obtained with the use of a white-light interferometer. A-D show a smooth surface due to fast peeling, while E-H show a rough surface due to slow peeling. A, B, E, and F are at low magnification, while C, D, G, and H are at high magnification. Image credit: B. N. J. Persson, et al. Explore further More information: B. N. J. Persson, et al. “Surface roughness of peeled adhesive tape: A mystery?” Europhysics Letters, 92 (2010) 46001. DOI: 1209/0295-5075/92/46001 Finding rough spot in surface measurement 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. The study’s authors, Bo Persson from FZ-Julich in Julich, Germany (who was also a coauthor of the X-ray study), Alexander Kovalev and Stanislav Gorb from the University of Kiel in Kiel, Germany, and Matthias Wasem and Enrico Gnecco from the University of Basel in Basel, Switzerland, have published their results in a recent issue of Europhysics Letters.In their study, the scientists used a white-light interferometer as well as an atomic force microscope to look at the tape’s sticky surface after it had been peeled off a hard substrate. They found that slowly peeling the tape leaves behind a rough, white surface on the soft rubber adhesive layer (the white color is due to the large light scattering from the rough surface). On the other hand, peeling the tape more quickly leaves behind a smoother, transparent surface (transparent because there is less light scattering from the smoother surface).In addition, the scientists were surprised to find that both the rough and smooth surfaces exhibited fractal scaling properties over a wide range of length scales, with a fractal dimension that is typical for surfaces produced by crack propagation. The scientists did not expect this result because of the influence of the surface free energy. That is, elastically soft solids such as the tacky rubber adhesive should deform at short length scales in order to reduce the surface free energy. This should result in a much smoother surface at short length scales (or high magnification) than would otherwise be expected. This effect had already been observed in a different context, but could not be detected on the rubber film of the peeled tape.last_img read more

Put your thinking cap on and type with your mind w Video

first_img More information: www.intendix.com/ Since the system only requires the movement of the eyes in order to function it could be used by people with severe spinal cord injuries or other conditions have the rendered arm movement and vocal cord use impossible or impractical. The device, which has been named intendiX, was shown off at Cebit.Labs. For those of you who are not familiar with the event Cebit.Labs is a section of the Cebit trade show that is devoted exclusively to showing off research projects. Citation: Put your thinking cap on and type with your mind (w/ Video) (2011, March 3) retrieved 18 August 2019 from https://phys.org/news/2011-03-cap-mind-video.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. Explore further CeBIT 2005: Sound Added to Text Messages for Talking Images IntendiX features a tight-fitting skull cap that has a number of electroencephalograph (EEG) electrodes attached to it. These are the Wet style of electrodes, so they do require a gel to function properly, though there is a dry version of the cap in the works. There is also a pocket-sized brainwave amplifier, and a Windows-based application that is designed to analyze the brainwaves received and translate them into letters on the screen. The setup can be connected via a Bluetooth wireless signal. Currently the fastest in-lab time has been .9 of a second per character, but that is after the users have been trained on the system. Untrained users testing the device have been a slow as 40 seconds per character. No word yet on when the device will be available to the public. (PhysOrg.com) — Guger Technologies, an Austrian-based company, has developed a computer interface that can work directly with the human brain. The interface allows a user to “type” short messages by staring at letters on the screen. Those messages can then be translated with text to speech software, giving a voice to those who cannot speak for themselves, a funky, robot voice. If speech isn’t on the users mind the messages can be sent the same way any other text would be over the web. © 2010 PhysOrg.comlast_img read more

Study shows whales dive deeper and longer when exposed to human produced

first_img In recent years, some groups have suggested that an apparent increase in the numbers of whales beaching themselves is due to exposure to mid-frequency active sonar (MFAS), but it has remained unclear how such an association could result in whales beaching themselves. More recently, researchers found that many whales stranded on beaches had gas bubble-associated lesions and fat emboli that were similar in nature to those seen in human divers that submerge too long or surface too rapidly. This led the researchers to consider the possibility that the whales have been beaching themselves due to decompression sickness, aka “the bends.”To find out if this might be the case, the researchers affixed tracking devices to 16 Cuvier’s beaked whales and monitored their movements for approximately 88 days in a location off the coast of Los Angeles associated with MFAS interference (from U.S. Navy submarines and helicopters) regarding whales. At the same time, the group also monitored and tracked all MFAS emissions from all U.S. Navy ships and submarines in the same area.The researchers report that the whales clearly reacted to the MFAS by diving deeper and staying down longer than they normally would—one whale dived for almost an hour longer than has ever been observed by any mammal. Proximity to MFAS also led to longer times between dives, which, the researchers noted, could adversely impact foraging. They also note that such behavioral changes were more defined the closer the whales were to MFAS sources. Interestingly, they also found that the whales appeared to react more strongly to weaker signals from helicopters than from submarines—which, they note, might be due to the more sudden onset of the signals.Prior to the study of whale beaching, it was not known that whales could suffer from decompression sickness, but data from this new study suggests that not only is it possible, it happens because the whales are trying to escape MFAS noise. Credit: CC0 Public Domain Citation: Study shows whales dive deeper and longer when exposed to human produced sonar (2017, August 30) retrieved 18 August 2019 from https://phys.org/news/2017-08-whales-deeper-longer-exposed-human.html More information: “Diving behaviour of Cuvier’s beaked whales exposed to two types of military sonar,” Royal Society Open Science (2017). DOI: 10.1098/rsos.170629 Fresh whale stranding on notorious New Zealand beach © 2017 Phys.orgcenter_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. Explore further A combined team of researchers from Marine Ecology and Telemetry Research and the U.S. Navy’s Naval Undersea Warfare Center Division has found evidence of whales diving deeper and longer than normal when exposed to sonar from submarines and helicopters. In their paper published in the journal Royal Society Open Science, the group describes their study, which included tagging whales and monitoring their behavior when exposed to artificial sonar signals. Journal information: Royal Society Open Sciencelast_img read more

Sculpting tradition in modernity

first_imgHis inspirations from his predecessors have kindled in him the spark of creativity, where rootedness to living tradition acted as a point of departure, which has ultimately brought him to the creation of a series of sculptures under the title ‘The Babu, the Nayika and the Cat’ based on the urban-folk forms of the paintings famously known as ‘Kalighat Pat’developed in 19th century Calcutta around the temple of Kalighat. This series was first exhibited at the Indian Art Fair 2012 held in Delhi. Also Read – ‘Playing Jojo was emotionally exhausting’The bronze and fibre-glass sculptures displayed in the present show posit all the characteristic and visual philosophy of his works mentioned above.The lyrical lines, the rhythmic volume, the concentrated mass emerging out towards the dynamic outward surface from the still central core, creating the negative space through synchronization of positive volume, the rhythmic distortion of mythical figures from naturalistic conventions – all these aesthetic attributes of his works postulate his position as a modern and modernist sculptor emanating traditionally oriented contemporary values. Also Read – Leslie doing new comedy special with NetflixApart from the bronzes of mythical and humanist subjects of his well known genre in this show there are six pieces of his Kalighat Pat based works, four of which are in coloured fibre glass and two in bronze.In developing these witty, humorous, lyrically rhythmic yet socially critical forms he has displayed a kind of post-modern values in the evaluation of a defunct tradition and using it to transpire some of the intrinsic features of contemporary life.last_img read more

Beyond the clichéd clicks

first_imgWith each passing frame of time, each new face and every place slowly explored, the colors seemed to sink deeper into my veins.  From colourful block prints, elaborate Mughal crafts to blue pottery and meenakari, Colors of India is more than just a story. It is a way of life. I heard new stories, created some and became a part of others and developed an identity which makes me feel proud to be an Indian,’ says Kaynat Kazi, an avid traveller and an amateur photographer.  Also Read – ‘Playing Jojo was emotionally exhausting’Hanging on the red bricked walls, with white threads were not pictures but tales; stories that we listened with our eyes wide open, as our minds wandered from Jaipur to Ladakh and beyond. The ambience of open air, with breeze flowing in, added to the flying imaginations of the visitors.  We have all often heard of statements like, ‘We should do something about the dying art’. Well, here is someone who has done her share. Coming from Delhi, she has travelled far and wide, alone and in a group, to cover the crafts that are dying.  Also Read – Leslie doing new comedy special with NetflixThis is for the first time that choosing our favourite was so difficult. From, zardozi, thathera, meenakari, bangle making to blue pottery, she has covered it all. Herself a lover of art, she truly worries about the fading culture that has defined India till date; its handicraft. ‘Colors of India is a journey of self discovery. It is a compilation of four years of experience, a  travel memorabilia  through seldom explored nooks and corners of the largest democracy of the world,’ says the beautiful woman. The show at Open Air Gallery at IHC wrapped up today amidst rave reviews from the visitors who trooped in to witness some incredible clicks.last_img read more

European Central Bank starts 12trillion monetary stimulus

first_imgThe European Central Bank has hit the launch button on its 1.1 trillion euro ($1.2 trillion) stimulus programme by starting to buy government bonds.The chief monetary authority for the 19 countries that use the euro confirmed on Monday it had begun the purchases, which aim to make credit cheaper, boost growth and raise inflation. ECB President Mario Draghi had announced the start date last week, sending stocks higher and the euro lower. The bonds are bought from banks and other financial institutions using newly printed money. Among the ECB’s chief concerns is low inflation – which at negative 0.3 per cent annually is a sign of the economic weakness that has plagued the currency union as it struggles with high government debt. Also Read – I-T issues 17-point checklist to trace unaccounted DeMO cashThe ECB has said it will buy 60 billion euros per month in government and corporate bonds through September 2016, and in any case until inflation turns convincingly upward toward the bank’s goal of just under 2 per cent. Yields on government bonds have already fallen in anticipation of the programme’s start. Some eurozone government bonds are trading at negative yields, meaning investors pay that government for loaning it money.One key effect of the programme is expected to be a weaker euro, which would help eurozone exporters. More euros in circulation help drive down the currency’s value, as expressed by its exchange rate. Also Read – Lanka launches ambitious tourism programme to woo Indian touristsLow or negative interest rates encourage investors to invest in a currency where rates are higher, such as the US German 10-year government bonds are now trading at yields of just 0.29 per cent, while 10-year US Treasurys yield 2.22 per cent.The euro traded at $ 1.09 on Monday, well down from just under $1.40 in May, 2014. Some analysts think it could be headed for parity — one euro for one dollar.last_img read more

Preserving what matters

first_imgThe Sadharan Brahmo Samaj may not be what it once was but it still runs one of Kolkata’s oldest libraries that continues to enlighten its readers with 25,000 rare tomes, journals, manuscripts  and paintings dating back to the 19th century. With most of the treasure trove in dire need of preservation and restoration, a modernisation drive has been undertaken by the Samaj authorities during 2015. Luminaries of the Bengal Renaissance like Shibnath Shastri, Anandamohan Bose, Nilratan Sarkar, Umesh Chandra Dutta, P C Mahalnobis, Dr Jagadish Chandra Bose, P C Roy and Bipin Chandra Pal contributed to the rare pile of books over the years. But many of these have grown brittle over time. Also Read – ‘Playing Jojo was emotionally exhausting’“The whole process of modernization including digitization of the books has begun but it is an expensive process and we could not do it as quickly as we wanted to for paucity of funds. As for restoration of paintings, three out of 19 have been completed and we plan to get three more restored in 2015”, Biswajit Roy, Library Secretary told Millennium Post.A portrait of Debendranath Tagore, father of Rabindranath Tagore, has been recently restored by art collector and restoration expert Ganesh Pratap Singh. Also Read – Leslie doing new comedy special with Netflix“The paintings are of great historical value since they throw light on some of the most gifted and inspiring personalities of the Bengal Renaissance”, says Singh, who recently displayed some of Rammohun Roy’s original letters in the library. Important journals, some of them a mirror of the times, include Tattabodhini, Tattakoumudi, The Indian Messenger, Bharati, Probashi, Sakal, have yellowed but provide scholars of theology, philosophy and history with priceless research material. Books from personal collections of Jagadish Bose, Pearychand Mitra and P Ray have also enriched the library’s rare possessions.Another art de object in possession of the library is a bust of Raja Rammohun Roy which was originally created in marble by the famous sculptor George Clarke. It is known that Rammohun Roy had modelled for Clarke’ when the original was being created. The replica was in possession of the Tagores of Jorasanko and was gifted in 1936 to the library and is still in its possession.The library allows the city’s research scholars and bookworms to read 5 days a week for a few hours every evening. However you can photocopy relevant sections from the books and periodicals at this heritage(founded 1895) institution.last_img read more

45 lakh school students under North Corporation bereft of insurance cover

first_imgIt has come to light that the North MCD, with around 4.5 lakh students of 765-odd schools under it, has stopped providing insurance facilities to its students.As per the report, the students enrolled in North MCD schools have not been able to avail insurance facilities from April this year due to non-renewal of the insurance terms. The Corporation, which is supposed to spend Rs 2.5 lakh per annum for the insurance of its students through a private company, is yet to make the payment for the contract renewal. The civic agency claims that the insurance company is seeking Rs 1.30 per children per year or nearly Rs 6 lakh in total, which is beyond its means. “The Corporation is facing a financial crisis hence it cannot bear a premium amount which is more than double in comparison to last year. We have been looking for a company which could provide services on lower premiums,” said a Corporation councillor. Also Read – Need to understand why law graduate’s natural choice is not legal profession: CJIRenu K Jagdev, Additional Commissioner (Revenue) of North Corporation said that the agency issued tenders in February and April but failed to finalise any of the companies. “In February, HDFC Insurance Company came forward with a rate of Rs 1.10 per children but the tender was not allotted as the company was a lone participant. In April, the existing insurance company, Bajaj Allianz, and HDFC insurance participated and the latter had quoted Rs 1.30 which was the lowest. The tender was not awarded due to some reasons and now the agency is gearing up for a fresh tender,” the Additional Commissioner said. Also Read – Health remains key challenge in India’s development: KovindLeader of Opposition in the North Corporation Mukesh Goel said that it’s unfortunate that the students, who fall under economically backward categories, are being deprived due to non-payment of a small amount. The students do not have an insurance coverage and the ruling BJP is paying no heed to this issue. “Last week, a nine-year-old boy died after a grille kept in the balcony of a Municipal school fell on him in North-west Delhi’s Swaroop Nagar due to negligence on the part of school authorities. The family did not get the insurance amount due to lack of coverage. The North Corporation must act like a responsible body by renewing the contract immediately,” Goel said.last_img read more

IT policy looks to transform Bengal into techproficient welfare society

first_imgKolkata: The Information Technology (IT) policy of the Mamata Banerjee government is aimed at transforming Bengal into a knowledge driven, technologically enabled welfare society, with extensive use of IT for increasing employment opportunities and promoting the state as a preferred investment destination.Chief Minister Mamata Banerjee had formally unveiled the IT policy of the state government on Monday, from the venue of the foundation stone laying ceremony of Silicon Valley IT hub at New Town, which was made available on the website of the state IT&E department on Tuesday.”Our emphasis will be on harnessing emerging technologies to be amongst the top global performers in IT and to spread relevant skillsets in expanding the workplace to areas such as digital marketing, 3D printing, animation, gaming, data analysis, big data and contributing to the electronic value chain. We will forge partnerships for promoting emerging technologies and PPP will be encouraged,” a senior official of the state IT department said.In a significant step to attract the IT companies in the state, the IT department will offer specific fiscal incentives that include 50 percent waiver of property tax for a period of 12 years (as per section 102B of West Bengal Municipal Act 1993) and extra 15 percent Floor Area Ratio (FAR) for IT buildings.”The Incentive Policies offered by the state department of Commerce and Industry and MSME department will be followed mutatis mutandis,” the official maintained.The fiscal incentives assume significance with the Mamata Banerjee government averse to special economic zone (SEZ) status for land to the IT players.”There will be an innovation platform to highlight the achievement of local companies and their cutting-edge research in the field of IT&E will be recognised. We are also coming up with a Centre for Innovation at Bantala, known as Sector VI in the administrative parlance,” the official added.The government is already focusing on creating clusters and hubs on analytics, fintech, animation, hardware etc.last_img read more