Month: August 2019

  • Fruit flies can detect heavy hydrogen study

    first_imgIn the present study wildtypes of different origin were shown to be quite different in their behavior towards odors of different origin. Credit: Rickard Ignell This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Dr Efthimios Skoulakis of the Alexander Fleming Biomedical Sciences Research Center in Vari, Greece and colleagues presented fruit flies (Drosophila melanogaster) with acetophenone, an odorant molecule often used in perfumes, in a T-shaped maze. In one branch the molecule contained normal hydrogen, while in the other the hydrogen atoms in the molecule were replaced by deuterium. The flies were able to choose the branch they preferred.The fruit flies, which are known to have a strong sense of smell, showed a definite preference for the molecule with more hydrogen and their aversion to the deuterated molecule grew as more hydrogens were replaced. When fruit flies that had been genetically modified to have no sense of smell were used, they showed no preference.The fruit flies’ ability to discriminate between the molecules was also demonstrated by successfully giving the flies mild electric shocks to their feet as they walked on the floor of the maze to condition them to selectively avoid either form of the molecule.Dr Skoulakis said the results support a new theory of olfaction first proposed in 1996 by co-author Dr Luca Turin, a biophysicist who is now at the Massachusetts Institute of Technology in Cambridge in the US. The new theory suggests odorants are detected by their vibrations rather than by their shape.Deuterium differs from the normal isotope of hydrogen in that its nucleus contains a proton and a neutron instead of just a proton. This roughly doubles the mass of the deuterium atom, and so while it has similar properties to normal hydrogen, the larger mass means bonds between deuterium and other atoms within molecules vibrate more slowly.The leading theory of how smell works is that odorant molecules are detected by receptor proteins in the olfactory membranes because of their shape, which fits into the shape of a cavity in the protein, like a key in a lock. If the molecule fits a signal is sent to the brain.Dr Turin’s theory is that the electrons of the odorant might be able to cross a receptor membrane only if the bonds in the molecule are vibrating at exactly the right frequency. Since an odorant with normal hydrogen will have different vibrational properties to the deuterated odorant, the two odorants should smell different even though their shape is the same. As further confirmation the researchers tested the fruit flies with nitriles, which have a similar vibrational frequencies to that of deuterium-carbon bonds. The fruit flies had an aversion to the nitriles as expected.Humans have not been shown to have the ability to discriminate between compounds containing normal and heavy hydrogen, but Dr Turin said there were unpublished reports of a similar ability in at least one dog, which ignores an odorant it is trained to detect if the molecule is deuterated.The paper is published in the journal Proceedings of the National Academy of Sciences (PNAS). Explore further More information: Molecular vibration-sensing component in Drosophila melanogaster olfaction, PNAS, Published online before print February 14, 2011, doi:10.1073/pnas.1012293108 In lean times, flies can’t survive without their sense of smell © 2010 PhysOrg.com Citation: Fruit flies can detect heavy hydrogen: study (2011, February 16) retrieved 18 August 2019 from https://phys.org/news/2011-02-fruit-flies-heavy-hydrogen.html (PhysOrg.com) — A new study by researchers in Greece and the US has found that fruit flies can discriminate between normal and heavy hydrogen (deuterium) isotopes, which adds weight to a new theory of how the sense of smell works.last_img read more

  • Closer look reveals how deep ocean squid uses leaky optical fibers to

    first_img Citation: Closer look reveals how deep ocean squid uses ‘leaky’ optical fibers to disappear into the background (2016, June 8) retrieved 18 August 2019 from https://phys.org/news/2016-06-closer-reveals-deep-ocean-squid.html (Phys.org)—A pair of researchers with the University of Pennsylvania has discovered how a type of deep ocean squid is able to remain unseen by predators despite having clearly visible eyes. In their paper published in Journal of the Royal Society Interface, Amanda Holt and Alison Sweeney describe their study of glass squid and how it has evolved to hide itself from predators that lurk in any direction. Glass squid live in the deep ocean and every part of their body except their eyes is clear, which helps to avoid being seen and eaten by predators from below. Such predators look up to find animals that create silhouettes against the distant light striking the surface of the water. Prior research had shown that the squid use what is known as counter-illumination to keep their eyes from being seen as part of a silhouette—they have organs below their eyes (photophores) that emit just enough light to match the light that is broadcast from above, preventing the eyes from being seen from below. But what about prey that live at approximately the same depths? That is what the research pair wanted to know, so they obtained some samples of the squid and put them under a microscope. They found that the photophores were actually made of cells that have a bend in them and that the walls were reflective—the two attributes together caused light to be channeled, like fiber optic cables. Looking even closer they discovered that the reflecting ability was not very efficient, which meant a lot of the light that was supposed to be channeled would leak out. At first, the researchers found this baffling, but then discovered that it actually served a very real purpose. In leaking small amounts of light, which turned out to be in many directions, the squid’s eyes became invisible to creatures that were at or near the same water level.The researchers confirmed what they had found by creating simulated leaking fiber cables that leaked in the amounts calculated from the squid, and by also reproducing the light levels in an experimental tank that simulated that in the environment where the squid lived—and found they matched. The end result, the researchers report was that the photophores were actually omnidirectional invisibility cloaks, noting that sometimes imperfections in a biological system might be producing better results than one that might seem perfect in other ways. © 2016 Phys.org Journal information: Journal of the Royal Society Interface More information: Amanda L. Holt et al. Open water camouflage via ‘leaky’ light guides in the midwater squid, Journal of The Royal Society Interface (2016). DOI: 10.1098/rsif.2016.0230AbstractGaliteuthis, a midwater squid, has photophores on the ventral surfaces of its eyes. These photophores emit bioluminescence to counter-illuminate the shadows cast by the eyes in downwelling sunlight, thereby hiding the eyes from upward-looking predators. The photophores consist of laminated fibre-like cells with semi-coaxial protein-dense layers around axial cytoplasm. These cells have been suggested to function as light guides: bioluminescence is an isotropic process used to hide in an anisotropic light environment, so any emission must be reshaped to be effective. We found a wide variation in cross-sectional geometries of photophore cells; some were more efficient at light guiding than others. We used a set of optical models to place these photophores in the context of the radiance where Galiteuthis lives and discovered a possible adaptive reason for this variation. In Galiteuthis’s horizontal and vertical range, ocean radiance is also quite variable. For complete camouflage, photophores must reproduce this variation in radiance using an isotropic source. Our models show that variation in the geometry of the photophore light guides reproduces the predicted variation in ocean radiance experienced by this species. By selectively activating geometrically distinct populations of photophore cells, the animal may reproduce the angular distribution of light at all positions in its habitat.center_img Explore further Scientists given rare glimpse of 350-kilo colossal squid Ventral view of a specimen of Galiteuthis glacialis recovered from the Ross Sea of Antarctica (71°59’S, 173°24’E). Specimen has a mantle length of 321 mm. Photograph by Darren Stevens of New Zealand, International Polar Year and the Census of Antarctic Marine Life. Credit: Wikipedia/ CC BY 3.0 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

  • Fussy ants found to improve chances of finding better new nesting sites

    first_img Explore further Rock ants live in cracks between rocks, which puts them at some risk due to weather or other animals destroying their nests. When this occurs, they find a new one. However, the researchers with this new effort found that there was more to the decision-making process than previously thought.To learn more about how the ants go about finding a site for a new nest, the researchers collected specimens of the ants and placed them into an artificial environment where they were kept alone and where possible nest sites were artificially created.In studying the ant behavior, the researchers learned that ants have very particular rules when choosing a nest site—it had to have a ceiling height of approximately 2mm, a gap of 1.5mm at the entrance, low light, and the interior had to be approximately 20 square centimeters in size. To gauge the suitability of nest sites, the ants were given an opportunity to choose among several options, some of which very closely suited their needs and others that did not. In so doing, the researchers found that some ants were content to live in any of the nests they came upon (demonstrated by laying down and spreading pheromones) while others were much more demanding. The ants that were more demanding, the team noted, were the same ants that behaved in ways that suggested they were not happy with a nest once chosen.In the wild, the researchers suggest, it is likely the fussy ants help the colony find a new nest because they would be more likely to visit more locations, ultimately leading to the best possible site. Still unclear, however, is the means by which different behavioral characteristics arise in different ants. The team plans to take a closer look to see if they can find the drivers for it. Desert ants found to have dual navigation systems 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. © 2017 Phys.org Journal information: Proceedings of the Royal Society Bcenter_img Acacia ants (Pseudomyrmex ferruginea). Credit: Ryan Somma/Wikipedia. (Phys.org)—A team of researchers with the University of Bristol has found that differences in behavioral traits among ants help when it comes to finding a new nest—at least with rock ants. In their paper published in Proceedings of the Royal Society B, the team describes their study of ant behavior in artificial nests, the differences in behavior they found and how they appeared to help them establish a new nest. Citation: Fussy ants found to improve chances of finding better new nesting sites (2017, February 2) retrieved 18 August 2019 from https://phys.org/news/2017-02-fussy-ants-chances-sites.html More information: Thomas A. O’Shea-Wheller et al. Variability in individual assessment behaviour and its implications for collective decision-making, Proceedings of the Royal Society B: Biological Sciences (2017). DOI: 10.1098/rspb.2016.2237AbstractSelf-organized systems of collective behaviour have been demonstrated in a number of group-living organisms. There is, however, less research relating to how variation in individual assessments may facilitate group decision-making. Here, we investigate this using the decentralized system of collective nest choice behaviour employed by the ant Temnothorax albipennis, combining experimental results with computational modelling. In experiments, isolated workers of this species were allowed to investigate new nest sites of differing quality, and it was found that for any given nest quality, there was wide variation among individuals in the durations that they spent within each nest site. Additionally, individual workers were consistent in spending more time in nest sites of higher quality, and less time in those of lower quality. Hence, the time spent in a new nest site must have included an assessment of nest quality. As nest site visit durations (henceforth termed assessment durations) are linked to recruitment, it is possible that the variability we observed may influence the collective decision-making process of colonies. Thus, we explored this further using a computational model of nest site selection, and found that heterogeneous nest assessments conferred a number of potential benefits. Furthermore, our experiments showed that nest quality assessments were flexible, being influenced by experience of prior options. Our findings help to elucidate the potential mechanisms underlying group behaviour, and highlight the importance of heterogeneity among individuals, rather than precise calibration, in shaping collective decision-making.last_img read more

  • Longest straightline ocean path on planet Earth calculated

    first_imgLongest sailable straight line path on Earth. Credit: arXiv:1804.07389 [math.HO] A pair of researchers, one with United Technologies Research Center, the other with IBM Research, has developed an algorithm that can be used to determine the longest straight-line path over water on Earth. In their paper uploaded to the arXiv preprint server, Rohan Chabukswar and Kushal Mukherjee describe their algorithm and what it revealed. Citation: Longest straight-line ocean path on planet Earth calculated (2018, May 2) retrieved 18 August 2019 from https://phys.org/news/2018-05-longest-straight-line-ocean-path-planet.html Explore further The two researchers created their algorithm in response to a post by an unknown person on Reddit (he has been identified as Patrick Anderson)—he posted what he claimed was the longest straight-line ocean trip possible on planet Earth. Along with the post was a graphic showing the proposed direct-line route, but no evidence of how it was found. Intrigued by the proposition, the two researchers wondered how they might actually calculate such a line. They knew that it would be possible to do it using a brute force approach, which would involve measuring the length of every stretch of ocean. But that, they noted, would likely require more computer power than they had. With a global map obtained from NOAA, which offered a resolution of 1.8 kilometers, they saw that a brute force approach would entail grinding through data describing over 230 billion great circles. And that would mean analyzing trillions of individual data points—clearly too much crunching for their available computer. To reduce the amount of work, they turned to mathematics—specifically, optimization algorithms called branch and bound. Such algorithms reduce the amount of searching by assigning routes to branches which themselves hold subsets of similar routes. As the algorithm runs, subsets are analyzed and branches eliminated, winnowing the amount of data requiring analysis until the branch that holds the solution is found.By coding and running their algorithm and inputting the map data, the researchers found it took just ten minutes for their laptop to provide an answer. Interestingly, the answer was the same given by Anderson, who reportedly got his information from an unknown Wiki post. The line runs between a point on a shoreline in Pakistan all the way to a Russian shoreline—a distance of approximately 32,089.7 kilometers. Journal information: arXiv A not-quite-random walk demystifies the algorithm Longest driveable straight line path on Earth. Credit: arXiv:1804.07389 [math.HO] © 2018 Phys.org More information: Longest Straight Line Paths on Water or Land on the Earth, arXiv:1804.07389 [math.HO] arxiv.org/abs/1804.07389AbstractThere has been some interest recently in determining the longest distance one can sail for on the earth without hitting land, as well as in the converse problem of determining the longest distance one could drive for on the earth without encountering a major body of water. In its basic form, this is an optimisation problem, rendered chaotic by the presence of islands and lakes, and indeed the fractal nature of the coasts. In this paper we present a methodology for calculating the two paths using the branch-and-bound algorithm. 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

  • Chinese MH370 relatives mark anniversary

    first_imgChinese relatives of passengers on board the missing flight MH370 gathered under a heavy police presence on Sunday to mark one year since the plane disappeared. About two thirds of those on board the Malaysia Airlines flight were Chinese, but relatives say they have faced harassment from authorities in their own country as they seek answers on the world’s biggest aviation mystery. China’s ruling Communist Party commonly clamps down in organised gatherings.last_img

  • Gastronomic delights

    first_imgShangri-La’s – Eros Hotel has on offer an enticing variety of authentic Malaysian dishes at its all-day dining restaurant Tamra. The festival that commenced on May 23 is organised in association with Tourism Malaysia and the Malaysian High Commission.  The Malaysian food festival features a wide variety of Malaysian specialties ranging from exquisite appetizers to traditional dishes. Chef Muhammad Lisarni brings the most authentic Malaysian gourmet flavours. Also Read – ‘Playing Jojo was emotionally exhausting’One can savour the various Malay cuisine flavours crafted by Chef Muhammad Lisarni, such as Kerabu Udang Dengen Soohoon (prawns and glass noodle salad), Serunding Ayam (spicy dried chicken floss), Sup Sayur Cendawan (plain oyster mushroom soup), Ayam Masak Lemak Cili Padi (chicken in spicy coconut and turmeric gravy), Sayur Munir Goreng (stir fried mix vegetables with coconut gravy) and Terung Goreng Bersambal (deep fried eggplant with chili paste). Also Read – Leslie doing new comedy special with NetflixDrawing inspiration from the streets of Malaysia, Tamra sets a festive tone with red lantern, dream catchers and hangings. This food festival is a voyage designed to transport the diner to the beautiful country of Malaysia. Live carts stationed in the restaurant’s cavernous halls housing authentic delicacies, are all set to capture the essence of a Malaysian marketplace.last_img read more

  • Indian citizens have become refugees in their own land CM

    first_imgKolkata: Raising concern over the exclusion of 40 lakh Bengalis in the final draft of the Assam’s National Register of Citizens (NRC) as it will be affecting Bengal and Bangladesh the most, Chief Minister Mamata Banerjee slammed the Centre of doing “vote politics” that has led those Indian citizens to become “refugees in their own land”.She left for Delhi on Monday afternoon after holding a Press conference at Nabanna in connection with Assam’s NRC issue. The Chief Minister will be meeting Union Home Minister Rajnath Singh during her stay there. Also Read – Rain batters Kolkata, cripples normal lifeBanerjee, who will be visiting Assam if necessary, is sending a team comprising MPs of her party to the state where “people are being isolated”.”Names of people of both Hindu and Muslim communities have been excluded. Eviction of Bengalis and Biharis is taking place in Assam,” Banerjee said adding that it is the outcome of the BJP’s “divide and rule” policy to isolate the citizens.Raising apprehension of “forceful eviction”, the Chief Minister said: “There is a lot to worry as the Centre has pressed an additional force of 15 companies and at the same time all connectivity including Internet services has been snapped.” In the same breath, Banerjee maintained that Bengal will be directly affected as Cooch Behar and Alipurduar districts share the border with Assam. “But we cannot behave like the Centre if any problem occurs,” she added. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedHolding both the Union government and Assam government responsible for the present situation, the Chief Minister added: “This is a game plan to forcefully evict humanity and human being. My question is that why the Centre had not opposed it in Court. They were silent and it shows that they were supporting the same. But we had opposed it.””I am worried as the peace may get disturbed and it may also leave an adverse effect on the entire country. The situation would not have taken this turn if the Centre had played a true role instead of doing vote politics,” Banerjee said adding that the people, whose names have been excluded are not Rohingyas and most of them have been residents of Assam for the past five to six decades. She also raised her concern for the future of those 40 lakh people and stated: “Names of many have been excluded despite having valid documents. They have been excluded on basis of surnames.”Stating that the Centre should have taken steps for amendment of the concerned Bill for protection of the people in Assam, the Chief Minister said: “Parliament can only give protection (to the people) and it is now in session.” This comes when the MPs of her party have already raised the issue in Parliament.She also slammed the Centre for not discussing the matter with the Bengal government as Assam is its neighbouring state and maintained: “I had received a letter on March 23 in 2018 stating that 86,849 foreigners were identified. Out of them 29,663 were directed to be sent back while 41,033 went missing. Seventy-one were sent back to Bangladesh while 833 including children and women are in six correctional homes of Assam.”Meanwhile, the Trinamool Congress, CPI(M) and Congress condemned the Assam issue in the state Assembly. “BJP is against the people of Bengal and is trying to wage a war against the Bengalis,” CPI(M) MLA Sujan Chakraborty said. The Leader of Opposition Abdul Mannan demanded a proposal to hold an all-party meeting on the issue.last_img read more

  • Cal HC directs WB govt to release 10 per cent MBBS docs

    first_imgKolkata: The Calcutta High Court upholding a State Administrative Tribunal (SAT) order today directed the West Bengal government to release 10 per cent in-service MBBS doctors for post graduate courses. Dismissing an appeal by the state government challenging the SAT order, a division bench of justices Debasish Kargupta and Sampa Sarkar directed it to comply with the order within two weeks. The SAT had on June 11 directed that the state government release 10 per cent of in-service MBBS doctors in state-run hospitals, which would roughly translate to a total of over 300 MBBS degree holders getting a chance to pursue MD/MS courses, as against 196 candidates allowed by the state, counsel for the petitioner doctors said. Also Read – Rain batters Kolkata, cripples normal life During the hearing, state counsel Amitesh Banerjee had told the court that rural healthcare services in the state would be in jeopardy if 10 per cent of the available MBBS doctors were allowed to go for higher studies as 37 rural health centres had only one doctor each, while 23 others had two each. He had also said that 180 seats were available for post-graduate courses in the medical colleges of the state for 2018 and the names of 196 candidates were released as per the merit list, with a waiting list of 16 candidates. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killed Challenging the list, 105 in-service doctors whose names appeared in the merit list after the said 196 names had moved the SAT. Opposing the state’s plea, the doctors’ counsel submitted that there was a huge dearth of specialist doctors at the state-run facilities in West Bengal and that it was for the benefit of the patients that more doctors were allowed to study MD/MS courses. The doctors’ counsel, Pratik Dhar claimed before the bench that the state-run hospitals in West Bengal had only 117 MD/MS doctors against a requirement of 1,700 post-graduate doctors. He submitted that there were 349 community health centres in the state and as per stipulation each should have at least five specialist doctors. With the SAT ordering that 10 per cent of the available MBBS doctors working at the state-run healthcare facilities be allowed to pursue higher studies, the government had moved the appeal before the high court.last_img read more

  • Syndicate importing edible oil from Bdesh busted 1 in cop net

    first_imgKolkata: Directorate of Revenue Intelligence (DRI) has busted a syndicate importing edible oil illegally from Bangladesh and arrested Sunil Kumar Gupta, director and main operator of M/s Kanpur Edibles Pvt. Ltd on Monday from Kanpur. It is alleged that the firm used to misuse the agreement on South Asian Free Trade Area (SAFTA) to avoid paying customs duty.According to DRI, the firm officials had hatched a conspiracy to avail the benefit of exemption of duty under SAFTA rules which is illegal. DRI got a tip-off that the said firm is evading tax by illegal use of SAFTA. Also Read – Bose & Gandhi: More similar than apart, says Sugata BoseDuring investigation, the firm was found to have imported 17,365.81 tonnes of refined palmolein, worth Rs 116.04 crore from various land customs stations at Gojadanga, Mahadipur and Petrapol in West Bengal. DRI has also seized seven live consignments containing 771.935 metric tonnes of imported refined palmolien, worth Rs 4.55 crore. Consignments imported in the past involving customs duty around Rs. 45.62 crore, are under investigation. If edible oils are imported from other than SAFTA countries, it attracts Basic Customs Duty (BCD) of 54% along with Social Welfare Surcharge (SWS) of 10%. If the same consignment is imported from SAFTA Countries, then the BCD and SWS are being waived, under the rules of Determination of Origin of Goods under the agreement on SAFTA. Gupta was produced before the Chief Metropolitan Magistrate, Kanpur on Tuesday with an appeal for his transit remand. After hearing, CMM, Kanpur granted transit remand for production of Gupta before the CMM, Kolkata.last_img read more

  • Kaushiks attempt to create peace in homophobic world

    first_imgGiving a poignant message about acceptance of all kinds of love in the society, the National Award winning film Nagarkirtan is all set to release on February 15. The film which is directed by Kaushik Ganguly will attempt to create a dialogue about the pertaining issue.Talking about the concept of the film, Kaushik said: “Many years have passed since Just another love story was made. Through the making of that film, I have come to know a lot of people who are beyond the conventional sexual preference for being a man or a woman. Getting to know them and be around them, for such a long time now, has opened a wide real world ahead. In this struggle of gender transformation from a man to a woman and vice versa, I have seen a quite a few acquaintances lose their lives. I doubt when they will get to live in peace in this homophobia-stricken world.” The director hopes that with his characters’ Madhu and Putis’ anguish would draw some affection from these people they are trying to live among. And, someday, all these little pains would culminate to make this a better world for them.last_img read more