Fusion scientist revives magnetic mirror machine with cool new idea

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. Citation: Fusion scientist revives magnetic mirror machine with cool new idea (2006, December 13) retrieved 18 August 2019 from https://phys.org/news/2006-12-fusion-scientist-revives-magnetic-mirror.html In the cooling scheme, Fisch uses one-meter-long radio frequency waves to control nuclear fusion by cooling the alpha particle byproduct of fusion. This cooling wave resonates with specific alpha particles, cooling them and reducing their energy so that they diffuse to the periphery and quickly exit the machine. The alphas’ lost energy could possibly even heat the remaining hydrogen ions to repeat the process.Fisch’s magnetic mirror idea would allow the alpha particles to travel both perpendicular and parallel to field lines due to the open geometry of mirror machines. Torus-shaped tokamaks, on the other hand, bend the magnetic field lines back on themselves for confinement, prohibiting axial movement of particles.Fisch explains that implementing alpha particle channeling would require two conditions. Because not all particles will be affected by the radio wave (only those with identical resonances), a connection must exist between high energy particles in the center and low energy particles near the periphery so that the center particles have a path of escape. Second, too much energy gain could cause energy losses (e.g. from collisions), but since high energy particles are pulled to the magnetic axis, a particle’s distance to the axis would limit its energy gain. Fisch also predicts that, by arranging for several regions of radio waves at different frequencies, a full range of particles can be cooled and ushered to exit. He estimates that quickening this ash removal process could increase fusion reactivity in certain designs by almost three times by making more room for hydrogen fuel ions. “Right now what we have is not quite a full-fledged concept, but it is certainly an idea for a concept,” he says. “I like this cooling effect, simply because it is a ‘cool’ effect. It is just very interesting, either for tokamaks or for mirrors, or even more generally than that.” To take the next step and use these ideas in a mirror machine applicable for confining fusion, Fisch cautions that, while there is the potential to improve efficiency using these ideas, the appropriate waves need to be identified in detail. “We’re still a long way from application,” he says. “The largest challenges in controlled fusion will be to make a device that has engineering simplicity, which is where the open confinement concepts have the advantage. The open confinement concepts need to work better as confinement devices, though.”Citation: Fisch, N.J. “Alpha Channeling in Mirror Machines.” Physical Review Letters 97, 225001 (2006).By Lisa Zyga, Copyright 2006 PhysOrg.com Explore further “Now that we know that we can get to the high temperatures need for fusion, we are more concerned with the next engineering steps, like shoveling fuel in and taking the ash and heat out of the machines,” Fisch explains to PhysOrg.com. “In the long run, I would not be surprised if people eventually came back to improved open system concepts for economical fusion energy such as the mirror.”In fusion, light particles (often hydrogen nuclei) fuse into heavier ions (such as helium nuclei, or alpha particles) and release their excess mass as energy. In order to fuse, the particles must reach a very high temperature (e.g. tens of millions of degrees), transforming into the highly conductive plasma phase. Without any control of the energy being produced, though, continuous chain reactions would result in a massive explosion like the hydrogen bomb. Popular in the ‘70s but in little use today, magnetic mirror machines consist of a magnetic field with high strength at the magnetic axis in the center and low strength on the periphery. This set-up enables confinement of charged particles—and now, as Fisch finds, can allow an efficient method for cooling, which is important for controlled fusion. Fisch explains that his cooling method—called an alpha-channeling effect—is similar to an effect that he and his colleague Professor Jean Marcel Rax predicted in 1992 for use in tokamaks, which are arguably the most popular candidate for producing fusion energy today. Like magnetic mirrors, tokamaks also employ magnetic fields to confine the hot plasmas required for fusion.“In the 1980s, there was a big shoot-out between tokamaks and mirrors,” Fisch explains. “The tokamak concept won out because it simply confined heat better, and now the mirror concept is practically gone within the US. But in the 1980s people just wanted to resolve the ‘proof-of-concept’—whether or not you could bring plasma up to thermonuclear temperatures. The tokamak simply had a better shot at this because it had the better seal on heat and particles. “Now that we know that we can get to those temperatures, we are more concerned with the next engineering steps, like shoveling fuel in and taking the ash out,” Fisch continues. “But that means opening up that seal on the tokamak to accomplish these goals. The mirror machine is already ‘open’—that was its problem—so these tasks are easy. In a way, the development path for the mirror was unfortunate, since the problems it solved easily were the engineering issues which were not at the top of the then-list.”center_img Best of Last Week: A loose thread in string theory, e-cigarettes harm brain stem, and diet’s role in obesity pandemic Since the development of the hydrogen bomb in the ‘50s, scientists have speculated that the power of fusion might serve as a renewable energy resource. Research has revealed the challenges of this goal, and although nothing close to such an application exists, recently, Professor Nathaniel Fisch from Princeton University has come up with a new idea for efficient fusion energy production based on the old concept of magnetic mirror machines. The GAMMA 10 tandem mirror at the University of Tsukuba in Japan is the world’s largest tandem-mirror plasma-confinement experimental device. In the future, such a device may use the cooling concept presented in this study by Nathaniel Fisch. Image credit: Teruji Cho, University of Tsukuba Plasma Research Center.last_img read more

Why Are Pygmies Short

first_img Explore further Squid could thrive under climate change Citation: Why Are Pygmies Short? (2007, December 21) retrieved 18 August 2019 from https://phys.org/news/2007-12-pygmies-short.html A Baka pygmy dance group pictured with US Ambassador R. Niels Marquardt in Lobeke National Park, Cameroon, in 2006. Source: US Federal Government. The question is controversial. Traditional explanations attribute pygmies’ small stature to minimizing caloric requirements and walking in dense forests. However, a new study by researchers at the University of Cambridge suggests that there are some problems with this explanation, and offers an alternative hypothesis.center_img Because of their short life expectancies, the researchers speculate that pygmies have had to shift their reproductive years forward. The average life expectancy at birth for different pygmy populations ranges from just 16 years to 24 years. Very few pygmy women reach the end of their reproductive period, as only a small percentage survive past age 40. In order to compensate for the lack of older reproductive women, natural selection has shifted the reproductive period forward. The fertility peak of age at first reproduction in the Aeta is around 15 years old, which reduces generation time and compensates for their short lifespan. In order to make this fertility shift, pygmies must reach full maturity faster than longer-lived human populations. For this reason, many pygmies stop growing at about age 12, several years earlier than other humans. Their childhood growth rate isn’t any more or less rapid than the growth rate of other (traditional) humans; pygmy youth are roughly the same size as non-pygmy youth. (This is the opposite of what is observed in cases of nutritionally induced stunting, where humans delay growth but achieve adult body size later). Instead of experiencing the “teenage growth spurt,” pygmies’ growth is simply truncated.Migliano also explained why pygmies’ growth rates don’t increase in the early years to compensate for their truncated growth at an early age.“I think that, besides the high mortality, they have very low calorie intake, so it is a combination of the two factors that lead to the different phenotypes,” she said. “The pygmies grow in the same rates as the Turkana [eastern African Pastoralists], who also suffer from poor nutrition – but because the Turkana have longer life expectancy, they have time to grow for longer and achieve larger body size. I would expect that a population with high mortality and high resources would grow fast and taller.” In other words, human height in general is partially influenced by lifespan.Still, the life history hypothesis leaves a few unanswered questions. For one, what originally caused the extremely high mortality rates among pygmies? The researchers suspect that the traditional hypotheses of environment, nutrition, thermoregulation, and other challenges may jointly or partially contribute to the high mortality rates observed in a wide variety of pygmy populations. In that case, the traditional explanations may be indirect causes of pygmies’ short stature, although the chain of effects would be much more complex than originally thought.More information: Migliano, Andrea Bamberg, Vinicius, Lucio, and Lahr, Marta Mirazon. “Life history trade-offs explain the evolution of human pygmies.” Proceedings of the National Academy of Sciences. December 18, 2007. vol. 104, no. 51, 20216-20219.Copyright 2007 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. Human pygmy populations are defined by an average male height of less than 5 feet (155 cm). By this definition, a wide range of pygmy societies exist today in parts of Africa, Malaysia, Thailand, Brazil, and Bolivia – different environments that don’t match the traditional hypotheses for small body size. Besides the differences within pygmy populations, there are also some non-pygmy populations that face some of the same physical challenges as pygmies but haven’t evolved a short stature. For example, many human populations live in dense forests and experience regular food shortages, and yet these populations have larger body sizes. Now, scientists Andrea Migliano, Lucio Vinicius, and Marta Lahr have performed a study on two pygmy groups from the Philippines, the Aeta and the Batak, and concluded that there may be a better explanation for pygmies’ short stature. Their study is published in a recent issue of the Proceedings of the National Academy of Sciences.The researchers point out that one characteristic unique to but common among many pygmy populations is their short lifespan compared to other humans. With this in mind, the researchers suggest that pygmies represent the “fast” extreme of life history strategies, with short stature being a side effect.“We first thought that we would find a relationship between small body size and increased fitness in pygmies – for example, that the shorter pygmies would have more advantages, such as higher fertility, than the taller ones,” Migliano told PhysOrg.com. “However, the smaller pygmies had lower fertility than the taller pygmies. So this gave us the idea that perhaps there was no advantage in being short among pygmies. “Then, when I went to the field, and started to interview them, I noticed the very high mortality rates – really high compared to any other population,” she said. “So when we checked that different pygmy groups followed the same pattern, we thought that these facts should be linked. Also, life history theory has been used for a long time to understand body size diversity among mammals, and we thought it should also apply to the understanding of human diversity.” 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

New research shows ants able to discern difference between threat levels

first_img(PhysOrg.com) — In an interesting study designed to determine how well ants are able to gauge a threat, Inon Scharf and his colleagues at Johannes Gutenberg University in Mainz, Germany, have shown that even simple ants are able to clearly distinguish between serious threats and those that aren’t so dire. In their paper, published on Ethology, the team found that a species of forest ant, Temnothorax longispinosus, are able to tell on sight if an invader is a serious threat, or just a mild one, and to react more stringently when the stakes are higher. To find out just how good ants are at distinguishing between threats, Scharf and his team assembled four different types of ants in their lab. The first was another species of ant unknown to T. longispinosus, the second were ants of the same species but from another nest; the third were ants from a different but familiar species, and the fourth were so-called slave-making ants; a very serious threat due to their tendency to kill off the queen and steal the young to enslave them as workers in their own nests.Temnothorax longispinosus, a forest dwelling ant specific to the American Northeast, generally have two forms of defense; they either bite and sting intruders or try to drag them out of the nest. In the study, the researchers found that upon discovering a slavemaker ant in the nest, T. longispinosus, came at the intruder with spread mandibles and began biting and stinging for all they were worth. When discovering any of the other ants in their nest, though, they instead opted for dragging, with different degrees of effort, based on the apparent degree of threat. The competitor ants were immediately dragged out, while the efforts to do the same with the familiar but different species ants were less urgent, and the species unknown to the ants were rarely attacked at all.From the study it appears that the ants have adapted to defending their nest in ways that are the most efficient; they only go full out when the threat is so severe that the survival of the nest is at stake. Dragging an intruder out involves fewer ants and doesn’t interfere with ongoing food retrieval activities. Common house ants form supercolonies, prosper in urban settings © 2010 PhysOrg.com 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. Temnothorax longispinosus. Image credit: Antweb.org More information: Differential Response of Ant Colonies to Intruders: Attack Strategies Correlate With Potential Threat, Ethology, DOI:10.1111/j.1439-0310.2011.01926.xAbstractAnimals are often threatened by predators, parasites, or competitors, and attacks against these enemies are a common response, which can help to remove the danger. The costs of defense are complex and involve the risk of injury, the loss of energy/time, and the erroneous identification of a friend as a foe. Our goal was to study the specificity of defense strategies. We analyzed the aggressive responses of ant colonies by confronting them with workers of an unfamiliar congeneric species, a non-nestmate conspecific, a co-occurring congeneric competitor species, and a social parasite—a slave-making ant. As expected, the latter species, which can inflict dramatic fitness losses to the colony, was treated with most aggression. A co-occurring competitor was also attacked, but the ants used different behaviors in their responses to both enemies. While the slavemaker was attacked by biting and stinging and was approached with spread mandibles, the competitor was dragged, a behavioral strategy only possible if the defending ant is similar in size and strength to the opponent. Non-nestmate conspecifics were treated aggressively as well, but less than the slavemaker and the co-occurring competitor, presumably because they are less easily recognized as enemies. An unfamiliar congeneric species was rarely attacked. This first detailed study comparing the aggressive responses of ant colonies toward slave-making ants to other species posing different threats indicates that the responses of ant colonies are adjusted to the risk each opponent poses to the colony.via BBC Citation: New research shows ants able to discern difference between threat levels (2011, July 5) retrieved 18 August 2019 from https://phys.org/news/2011-07-ants-discern-difference-threat.html Explore furtherlast_img read more

New research suggests initial mass function for galaxies not universal

first_img Citation: New research suggests initial mass function for galaxies not universal (2012, April 26) retrieved 18 August 2019 from https://phys.org/news/2012-04-mass-function-galaxies-universal.html © 2012 Phys.Org More information: Systematic variation of the stellar initial mass function in early-type galaxies, Nature 484, 485–488 (26 April 2012) doi:10.1038/nature10972AbstractMuch of our knowledge of galaxies comes from analysing the radiation emitted by their stars, which depends on the present number of each type of star in the galaxy. The present number depends on the stellar initial mass function (IMF), which describes the distribution of stellar masses when the population formed, and knowledge of it is critical to almost every aspect of galaxy evolution. More than 50 years after the first IMF determination1, no consensus has emerged on whether it is universal among different types of galaxies2. Previous studies indicated that the IMF and the dark matter fraction in galaxy centres cannot both be universal3, 4, 5, 6, 7, but they could not convincingly discriminate between the two possibilities. Only recently were indications found that massive elliptical galaxies may not have the same IMF as the Milky Way8. Here we report a study of the two-dimensional stellar kinematics for the large representative ATLAS3D sample9 of nearby early-type galaxies spanning two orders of magnitude in stellar mass, using detailed dynamical models. We find a strong systematic variation in IMF in early-type galaxies as a function of their stellar mass-to-light ratios, producing differences of a factor of up to three in galactic stellar mass. This implies that a galaxy’s IMF depends intimately on the galaxy’s formation history. (Phys.org) — Over the past several years there has been debate in the astrophysics community regarding the distribution of stars in galaxies, specifically their mass range. Astronomers use an initial mass function (IMF) to calculate the numbers of different kinds of stars in any given galaxy, but what’s not been clear is whether the IMF applies to all galaxies of all types. Now, a large international group of astronomers has found after studying data form 260 galaxies that the distribution of stars in early galaxies appears to be different from the distribution of stars in galaxies that formed later in time, casting doubt on the dependability of the IMF. They report their findings in their paper published in the journal Nature. Differentiating between the stellar and dark matter with integral-field stellar kinematics. Image: Nature, doi:10.1038/nature10972 Because some stars are too small to be studied individually, astronomers have come up with a way to measure the number of stars of different types in a galaxy by measuring the spectrum for the entire galaxy and then applying an initial mass function to it. Doing so gives a good approximation of the number of stars in any given mass range. The problem up till now however, is that it’s not been clear if the same IMF applies to all types of galaxies (spiral, elliptical or irregular). To find out, the researchers turned to the ATLAS3D project (a multi-wavelength survey of 260 so-called early type, i.e. elliptical galaxies) to help them generate a two dimensional distribution of stars in galaxies along with their statistical spectrums.Using the data they’d extracted, the team built several models (varying the dark matter composition) to generate galaxy structures. In so doing, they found that the ratio of mass to light from just the stars in their models (minus gas and dark matter) for some elliptical low mass galaxies did indeed look like spiral galaxies. But they also found some that did not, which means that the IMF is not universal. They also found generally the same results no matter which dark matter composition they used, which means of course that the results obtained were independent of mass.The team says this all means that a birthing star is influenced by the galaxy in which it is born. But that creates another problem, because prior research has shown that at least some large galaxies were created by the merging of smaller galaxies. But since the mass of the star doesn’t change over time, how could its current state reflect the galaxy in which it was born if it resides in a merged galaxy? The researchers don’t know, but suggest a serious rethinking of the IMF will have to be done to see if it actually holds any real value.center_img Explore further An abundance of small stars Journal information: Nature 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

Researchers find correlation between face shape and procreation rates and rank in

first_img This is not the first study to look for a correlation between male face shape and aggressive behavior. In 2008, Canadian researchers Justin Carré and Cheryl McCormick compared face shape and aggression in male hockey players—they found wider-faced men on average spent more time in the penalty box.In this new effort, the researchers relied on books commemorating Finnish soldiers who served in WWII. Photographs showing the soldiers’ faces were displayed along with personal data such as information marital status, number of children, rank achieved, etc. Also listed was information about where they had served and if they had survived the war.Loehr and O’Hara scanned the faces of 795 of the soldiers (from three regiments) and then used a simple algorithm that gave a ratio of face height to width to come up with a fWHR for each one of them. Personal data given for each soldier was entered into a database along with the fWHR. Graphing software was then used to reveal trends.In analyzing the graphs the researchers found that wide-faced men tended to have more children than those men with narrow faces. They also found that narrow-faced men tended to move up in rank more often than wide-faced men did. Face shape did not, however, appear to be connected to soldier survival rates in war. The researchers theorize that this is more likely due to modern warfare techniques and practices than aggressiveness in soldiers—when a shell lands in a foxhole, they note, everyone dies. They propose that wide-faced soldiers in more distant wars might have done better than their narrow-faced peers did if they were indeed more aggressive, as the Canadian study suggests. The thinking here is that aggressiveness would be an advantage in wars where soldiers had to rely on their own skills to survive, rather than sophisticated weapons. © 2013 Phys.org. All rights reserved. Finnish troops who participated in the Winter War 1939–1940 and the distribution of (a) scaled fWHR, (b) predicted probability of surviving the Winter War (adjusted so the posterior mode at mean face width is 0.85). Figure contains all 795 individuals. (c) Total number of children for fallen soldiers and (d) probability of attaining a rank depending on fWHR. Facial width increases with values. Dark shaded area represents 50% highest posterior density region and light shaded area represents 95% highest posterior density region. Credit: Biology Letters, doi:10.1098/rsbl.2013.0049 More information: Facial morphology predicts male fitness and rank but not survival in Second World War Finnish soldiers, Published 8 May 2013 doi: 10.1098/rsbl.2013.0049AbstractWe investigated fitness, military rank and survival of facial phenotypes in large-scale warfare using 795 Finnish soldiers who fought in the Winter War (1939–1940). We measured facial width-to-height ratio—a trait known to predict aggressive behaviour in males—and assessed whether facial morphology could predict survival, lifetime reproductive success (LRS) and social status. We found no difference in survival along the phenotypic gradient, however, wider-faced individuals had greater LRS, but achieved a lower military rank. 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 furthercenter_img (Phys.org) —Researchers in Finland, using photographs of soldiers marked with associated personal data have found that facial width to height ratio (fWHR) played a role in how many children they had and their rank. In their paper published in the journal Biology Letters, researchers John Loehr and Robert O’Hara describe how they measured the faces of men found in a war tribute book and compared them with personal data. Their study was part of an effort to see if they could find any correlations between wide-faced men and survival rates in war (possibly connected to aggressiveness). In so doing, they discovered some clear associations between wide faced-men and the number of children they had. They also found that narrow-faced men tended to rank higher than wide-faced men did. Citation: Researchers find correlation between face shape and procreation rates and rank in male soldiers (2013, May 9) retrieved 18 August 2019 from https://phys.org/news/2013-05-procreation-male-soldiers.html Journal information: Biology Letters Having a short wide face may indicate sporting potential, study showslast_img read more

Watch company develops wristwatch with its own atomic clock

first_img © 2013 Phys.org The Bathys Cesium 133 wristwatch is reportedly capable of accuracy to one second in 1000 years according to a report in Watchuseek. Dr. Patterson is quoted in the report: “The technology found in this watch is something even a decade ago no one could imagine existing in such a small package.” He said that “Within a single chip there is a laser, a heater, a sealed cavity of cesium gas, a microwave filter and a photodiode detector.” He also said that, “Using the exact same principle of counting hyperfine lines of excited cesium 133 atoms used by the National Institute of Standards and Technology (NIST), our watch is able to achieve unprecedented levels of accuracy; on the order of 1 second per thousand years.” As for display, this is a traditional analog watch dial. The batteries are rechargeable lithium batteries. Goals are now to reduce the size and increase the battery life. When ready, a limited edition of 20 watches is planned for release. The estimated price of each Bathys Cesium 133 atomic clock watch is $12,000, according to the report.A forum of responses to the atomic watch news went up on the Watchuseek site, with some respondents taking issue with the size. One comment was that the definition of wristwatch was undergoing a stretch and another remarked that it looked like a clock strapped on to a wrist, while other posts expressed interest in what the company was trying to achieve. A response from “BathysHawaii” surfaced in the WatchuSeek forum with this to say: “It IS large…it’s huge in fact. But this is just a proof-of-concept prototype. You can’t get to the sleek watch we’d want to make until we made a rather crude version to test things such as integration, COM and power. There’s still a long way to go—but the point is that we’ve got a genuine cesium atomic oscillator functioning on the arm for the first time ever. It blows me away frankly that we’ve done this.” Explore further NIST ytterbium atomic clocks set record for stability Bathys Hawaii, a US-based watch company, has created the Cesium 133, a prototype wrist watch that has its own atomic clock. The fact that the clock is self-contained, integrated into the wristwatch, is the distinguishing factor. The clock does not need to collect information from an external source to keep accurate time, unlike watches using a government-generated radio signal as the external source. Bathys founder Dr. John Patterson and engineer George Talbot developed this watch. (German chemists Robert Bunsen and Gustav Kirchhoff discovered cesium in 1860 through flame spectroscopy. Cesium subsequently has been widely used in atomic clocks, and the first accurate cesium clock is credited to Louis Essen in 1955 at the UK National Physical Laboratory. The NPL is the UK’s measurement institute for developing accurate measurement standards.)center_img More information: www.watchuseek.com/news/bam-ba … watch-the-cesium-133forums.watchuseek.com/f2/bam-b … um-133-a-921820.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. Citation: Watch company develops wristwatch with its own atomic clock (2013, October 2) retrieved 18 August 2019 from https://phys.org/news/2013-10-company-wristwatch-atomic-clock.htmllast_img read more

Soil bacteria found to produce mosquito repelling chemical stronger than DEET

first_imgAedes aegypti mosquitoes after an experiment. The lack of red in their guts indicates the compounds repelled the mosquitoes, which chose not to feed. Credit: Mayur Kajli Journal information: Science Advances DEET has been the leading mosquito repellent since the late 1940s and multiple studies have shown it to be safe to use—still, some believe its synthetic nature suggests it might be causing harm. Because of that, scientists have continued to look for a natural repellent. In this new effort, the researchers report that they have found a naturally occurring chemical that is even more repellent than DEET, though it will have to undergo extensive study to see if it is safe to use.The researchers report that their study began with Xenorhabdus budapestensis, a type of bacteria that takes up residence in soil-dwelling nematodes. The nematodes actually use the bacteria to help them parasitize insects. The researchers wanted to learn more about how the bacteria help kill insects and, in the process, found that mosquitoes were quite averse to its presence. This suggested the bacteria produced a chemical that caused the mosquitoes to stay away. To find out what it was, the researchers built an animal stand-in using a membrane filled with fake blood and then covered it with cheesecloth laden with chemicals from the bacteria. They put the stand-in inside of a container where they could release mosquitoes and used it to narrow down the chemicals produced by the bacteria to just one—one that was a member of a class called fabclavines. A trio of researchers at the University of Wisconsin has discovered that a common soil bacterium produces a chemical that is more effective in repelling mosquitoes than DEET. In their paper published in the journal Science Advances, Mayur Kajla, Gregory Barrett-Wilt and Susan Paskewitz describe their search for the chemical made by the bacteria and their hopes for its future. Aedes aegypti mosquitoes engorged after feeding on a red-colored mosquito diet during a control experiment in which water was used in place of repellent. The experiment showed a cloth coated with compounds extracted from bacteria is an effective repellent. Credit: Mayur Kajli Citation: Soil bacteria found to produce mosquito repelling chemical stronger than DEET (2019, January 17) retrieved 18 August 2019 from https://phys.org/news/2019-01-soil-bacteria-mosquito-repelling-chemical.html © 2019 Science X Networkcenter_img More information: Mayur K. Kajla et al. Bacteria: A novel source for potent mosquito feeding-deterrents, Science Advances (2019). DOI: 10.1126/sciadv.aau6141 Scientists investigate how DEET confuses countless critters 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 Credit: University of Wisconsin-Madison When applied via the cheesecloth, the researchers found that the mosquitoes would rather starve to death than go near it. Further testing showed that the chemical was up to three times more repellent than DEET. The team also found that high concentrations of the chemical served well as a repellent, while small concentrations worked well as a deterrent from drinking the blood from a treated surface. The researchers note that their work is purely preliminary, they have no idea if the chemical would be safe for human use, or if it could be made in mass quantities.last_img read more

Interpreting the malady that is Jhumpa Lahiri

first_imgIt’s always exciting when an Indian author is considered for a prestigious award abroad. Even if that author is Jhumpa Lahiri, who would have spent little more than a few holidays in the country of her parents’ birth. But my relationship with Lahiri has been a difficult one – both as a reader and a journalist. And so it was with mixed feelings that I received the news of her having been long-listed for the Booker Prize for her yet to be released novel The Lowland. Also Read – ‘Playing Jojo was emotionally exhausting’I was in college when Lahiri’s first collection of short stories, The Interpreter of Maladies, was released and won the Pulitzer award. It became something of a necessity to celebrate her work, much as a doting parent celebrates the first recitation or painting by a favourite child. My literature professor certainly believed I should like the book. And I still considered myself too young to be a sound critic of literature and confess what I really thought of it. Oh it’s not as if I didn’t think it was beautifully written. But I had a problem of principle with the subjects, or rather her representation of the Indian community, abroad and in India. It was, I felt, too stereotypical, too forced. I could tell her that you didn’t have to grow up in the US to know little of Indian history.  Also Read – Leslie doing new comedy special with NetflixEven students studying in one part of India, have little clue about the history and culture of another part. I could tell her of cousins who have grown up abroad and seemed totally rooted there, and no we didn’t make them repeat the names of their American classmates as part of any game played in candle light as one of Shoba’s relatives does in one of the stories. I could tell her that children born in the eighties and nineties in India, would as often shy away from watching their parents snap endless number of green chilies with their rice and dal meal and go for a pizza themselves, much like their counterparts in the West.  And if you studied in a good English medium school in India, you had no trouble understanding Hollywood movies… the list of things I could tell her was endless.And herein lies my second peeve point – this time as a journalist, which is the wall that she builds around herself. I have repeatedly heard a senior colleague’s account of Lahiri’s closely guarded wedding in Calcutta in 2001. The family had done its best to respect Lahiri’s wish that it be a private affair, even going to the extent of setting dogs at the paparazzi members gathered outside the venue. But the venue, menu and all details of the wedding were an open secret with some friend or family member eager enough to inform, albeit, on condition of anonymity. I had a first hand feel of it, when the author returned to Calcutta for her daughter’s first rice ceremony. This time it was an eager aunt who was ready to spill the beans, even though the author and her family remained elusive. Of this I was certain, however, that it was not shyness that held back Lahiri from interacting with the media, from being more open, as her family had claimed during her wedding. The distance she maintained was calculated and by making herself inaccessible in general, she kept alive an interest about her, that ensured more than normal coverage on those rare occasions when she did subject herself to be interviewed – during the promotion of the movie Namesake, based on her novel of the same name or before the release of her second collection of short stories Unaccustomed Earth. Perhaps it was necessary. As a later day author explained to me, ‘To write a good book is not enough, you have to sell it.’ Some might go on a publicity spree, some price their books a certain way. Lahiri, chose distance. And I can’t say it’s not a classy way of selling yourself.Meanwhile, somewhere down the years, the reader in me had lost interest in her work. I had read The Namesake and again been troubled by the recurring theme of discomfort with one’s identity, of not being able to either accept or let go of one’s roots. I didn’t read Unaccustomed Earth. And it was with mixed feelings that I picked up The Interpreter of Maladies again after learning that Lahiri is being considered for the Booker. Imagine my surprise therefore, when I could identify with the screaming silence between the estranged couple in A Temporary Matter, empathise with Miranda’s aching desires in Sexy, understand Mrs Das’s need to unburden herself to a tour guide in The Interpreter of Maladies… Perhaps over the years, I have matured enough to tune out the forced Indianness of the stories and learnt to appreciate the play of emotions and relationships. I am now looking forward to reading Unaccustomed Earthand The Lowland. My only wish, as a now sincere reader, is that she would set her characters free, relieve them of their burden of assumed identity and let them be global citizens with universal feelings.last_img read more

Scrapping of iconic Indian warship INS Vikrant begins

first_img‘We began the process of breaking INS Vikrant yesterday and it will take at least seven to eight months to complete the job,’ Abdul Zaka of ship breaking company IB Commercial (IBC), which had won the bid for the decommissioned ship for Rs 60 crore, told . Zaka said after the Supreme Court in August rejected the PIL to convert the ship into a maritime museum, IBC obtained mandatory permissions from different government authorities for dismantling it at ship breaking yard at Darukana in south Mumbai. Around 200 men have been engaged for the job. Also Read – Need to understand why law graduate’s natural choice is not legal profession: CJIBefore the Supreme Court’s verdict, the Maharashtra government had expressed its inability to maintain the vessel inducted into the Navy in 1961 and decommissioned in January 1997. In January 2014, during the hearing of a Public Interest Litigation that opposed the plan to scrap the ship, the defence ministry had told the Bombay high court that it had completed its operational life.Responding to the demand for converting it into a museum, Maharashtra government had expressed its inability to preserve it as a museum, citing financially troubles. The majestic-class aircraft carrier, purchased from Britain in 1957, played a key role in enforcing the naval blockade of East Pakistan during the Indo-Pakistan war of 1971.last_img read more

Keeping up to the Delhi spirit

first_imgWith an aim to promote cultural tourism in the city, Delhi Tourism has been hosting a series of cultural events under the banner of Dilli Haat Utsav. This festival started on September 13, 2014 and will continue till March 31, 2015. In a bid to boost international as well as local tourism in Delhi, the festival will be on for nearly 6 months. Dilli Haat Utsav offers evenings full of cultural performances every weekend at all three Dilli Haats, at INA, Janak Puri and Pitampura. The festival is being held in collaboration with Department of Art, Culture and Languages (Govt. of Delhi) and gives a promising platform to new artistes to perform in the city. Also Read – ‘Playing Jojo was emotionally exhausting’This weekend also witnessed some enthralling performances. Dilli Haat INA witnessed Usha Chabra who charmed the visitors with her mastered story-telling skills on Saturday and Dushyant Ahuja’s Sindhi Folk Musical Group from Sindhi Academy presented light music on Sunday.Dilli Haat Pitam Pura saw Santanu Chakraborty and group from Sahitya Kala Parishad showcasing Bharatnatyam dance performance on Saturday, while Natras Cultural Group from the same academy enthralled the visitors with folk dance on Sunday.Dilli Haat Janak Puri hosted National Bamboo Expo Mart (Baans Bazar) from 28-30 November. It was organised by National Bamboo Mission.last_img read more