Bacteria shown to smell ammonia

first_img(PhysOrg.com) — A new study provides the first evidence that bacteria respond to odors, which according to one of the researchers may be the earliest evolutionary example of olfaction. Microbiologist Reindert Nijland from the University Medical Centre at Utrecht in the Netherlands, and marine microbiologist Grant Burgess, from the University of Newcastle in the UK, were studying the formation of biofilms by common bacteria that live in soils (Bacillus licheniformis), and discovered the microbes were sensitive to the presence of ammonium sulfate, which bacteria metabolize and convert to ammonia, which is a valuable nutrient because it contains nitrogen, which is then used in the production of proteins and nucleic acids. Some ammonia is released to the air in the process.In the study the researchers used an array consisting of 96 wells and filled one half with a culture medium intended specifically to promote biofilm formation, and the other half with a general, nutrient-rich culture medium. Biofilms were formed in the wells in the biofilm section, but formed best in the central wells closest to the nutrient-rich medium containing ammonium sulfate. Bacteria in these wells were releasing ammonia as they digested the ammonium sulfate. Nijland and Burgess then experimented with different media and found that media with ammonium sulfate as one of the nutrients produced the greatest volume of biofilms in the central wells. The same pattern was produced if the media was a simple aqueous solution of ammonia, which suggests the bacteria can sense the volatile ammonia and react by growing a biofilm towards its source. This would be an advantage to the bacteria as ammonia indicates the presence of a rich source of nutrients nearby.Bacteria have previously been shown to respond to gases such as carbon monoxide and oxygen, but Nijland said these gases do not have odors and so the response to them cannot be olfactory. He said it makes no sense to “smell” oxygen as it is always around. “You smell things that give important information,” Nijland said. He also countered criticism of the research suggesting the bacteria were responding to changes in pH of the solution as it absorbed ammonia, by saying the effect was observed even when concentrations were too low to have much effect on pH, and the culture medium was also buffered to ensure large pH shifts did not occur.Nijland said he hoped the results might lead to ways of preventing the formation of biofilms, which are resistant to antibiotics and make bacteria that cause disease more of a threat.The paper is to be published in the Biotechnology Journal. © 2010 PhysOrg.com Bacteria breakthrough is heaven scent Explore further Citation: Bacteria shown to ‘smell’ ammonia (2010, August 18) retrieved 18 August 2019 from https://phys.org/news/2010-08-bacteria-shown-ammonia.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.last_img read more

Robots learn to create language

first_imgThe go-to game allows the agents to test their toponymic lexicon by specifying a target location (B) to meet at. Image credit: Ruth Schulz Citation: Robots learn to create language (2011, May 17) retrieved 18 August 2019 from https://phys.org/news/2011-05-robots-language.html © 2010 PhysOrg.com Video showing Lingodroids playing a location language game. Schulz, R., Glover, A., Milford, M., Wyeth, G., & Wiles, J. (2011) Lingodroids: Studies in Spatial Cognition and Language, ICRA 2011, The International Conference on Robotics and Automation, Shanghai, China, May 2011 The Lingodroids develop language in the way that most human languages have probably developed, but making up words to name the places that they visit, and then share that name with the other around you. The bots basically find something that they have not seen in the past, create a word based on a random combination of syllables, and then tell the other robot the word that they have just created. Then the robots memory files will link to the word to that specific location. Currently the robots are learning new words by playing games, and can only name locations, but the researchers hope that in the future these Lingodroids will be able to create a more complex language. Explore further Toyota’s musical robots (w/ Video)center_img More information: Research paper: Schulz, R., Wyeth, G., & Wiles, J. (In Press) Are we there yet? Grounding temporal concepts in shared journeys, IEEE Transactions on Autonomous Mental DevelopmentMore info: itee.uq.edu.au/~ruth/Lingodroids.htm This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (PhysOrg.com) — Communication is a vital part of any task that has to be done by more than one individual. That is why humans in every corner of the world have created their own complex languages that help us share the goal. As it turns out, we are not alone in that need, or in our ability to create a language of our own. Researchers at the University of Queensland and Queensland University of Technology have created a pair of robots who are creating their own language. The bots, which are being taught how to speak but not given specific languages, are learning to create a lexicon of their own. The bots, which have been aptly named Lingodroids, consist of a fairly basic setup when it comes to hardware. The robot consists of a mobile platform that has been equipped with a camera, a laser range finder, and a sonar setup that allows for the mapping and avoidance of obstacle. In order to allow them to talk, they are also equipped with a microphone and speakers. last_img read more

Curves in spacetime violate Heisenbergs uncertainty principle

first_img Time travel theory avoids grandfather paradox (Phys.org)—If an object traveling through spacetime can loop back in time in a certain way, then its trajectory can allow a pair of its components to be measured with perfect accuracy, violating Heisenberg’s uncertainty principle. This new finding involves a particular trajectory called an open timelike curve (OTC), which is a special case of a closed timelike curve (CTC), a theoretical concept that has previously provoked controversy because it raises the possibility of traveling backwards in time. According to Heisenberg’s uncertainty principle, measurements of any pair of variables must have at least a minimum amount of error. The most well-known example of the pair of variables is position and momentum, but the principle applies to any two variables that have a mathematical relationship which makes them conjugate variables. The uncertainty principle is thought to be an inherent property of quantum systems due to their wave-particle duality, rather than any observational limitations. Although previous studies have found that CTC models can theoretically violate the uncertainty principle, nobody knew that this could happen for the special case of an OTC.Now, physicists Jacques Pienaar, Tim Ralph, and Casey Myers at The University of Queensland in Australia have theoretically shown that OTCs can allow scientists to measure a pair of conjugate variables of a quantum state to an arbitrary degree of accuracy forbidden by the uncertainty principle. The finding could have implications for quantum gravity and change the way that scientists view quantum uncertainty.”There is some speculation that the Heisenberg uncertainty principle might be different in a future theory of quantum gravity,” Pienaar told Phys.org. “However, most of these studies suggest that quantum gravity will introduce more uncertainty. Our model suggests the complete opposite: that a theory of quantum gravity might actually remove the uncertainty of quantum mechanics.”This perfect measurement ability arises from the nature of OTC trajectories. As the physicists explain, OTCs are the simplest and most normal type of CTCs. Whereas CTCs form closed loops in time that allow systems to affect events in their own past, OTCs form open loops in time and do not allow systems to interact with previous versions of themselves. These interaction-free OTCs overcome some of the paradoxes associated with time travel, such as the grandfather paradox in which a time traveler kills their own grandfather, preventing their own existence. More information: J. L. Pienaar, et al. “Open Timelike Curves Violate Heisenberg’s Uncertainty Principle.” PRL 110, 060501 (2013). DOI: 10.1103/PhysRevLett.110.060501 Copyright 2013 Phys.org All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of Phys.org. 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.center_img Citation: Curves in spacetime violate Heisenberg’s uncertainty principle (2013, February 19) retrieved 18 August 2019 from https://phys.org/news/2013-02-spacetime-violate-heisenberg-uncertainty-principle.html Explore further (a) A closed timelike curve, in which p2 is a chronology-respecting system, and p1 is a time-traveling system that can jump from point tA to the past point tB through a spacetime wormhole, has the ability to interact with itself in the past. (b) In an open timelike curve (OTC), the system cannot interact with itself in the past. In the new study, physicists have theoretically shown that OTCs can violate Heisenberg’s uncertainty principle, provided p1 is entangled with p2. This proposal could be tested by performing experiments on entangled systems in Earth’s gravitational field. Credit: J. L. Pienaar, et al. ©2013 American Physical Society Despite such paradoxes, CTCs in general are compatible with general relativity; however, they are not compatible with quantum mechanics. One way to make them compatible is to extend quantum mechanics in a way that resolves the paradoxical aspects of CTCs. An example of such an extension is the Deutsch model, which makes the mathematics of quantum mechanics nonlinear, allowing for CTCs. Previously, scientists have shown that this nonlinearity leads to some unusual properties, such as the possibility to build a super quantum computer that can quickly solve some complex problems called NP-complete problems, a task that would take trillions of years using today’s computers.In the new study, the physicists have shown that the Deutsch model’s nonlinear mathematics also applies to OTCs, where there is no interaction between the past and present, provided that entanglement exists between the time-traveling system and an external system. To reach this conclusion, the physicists calculated what happens when quantum states travel through a quantum optics circuit that contains an OTC. In this theoretical situation, two quantum states are “squeezed” in orthogonal directions. After the states cycle through the circuit several times, the scientists found that they could measure the orthogonal components with arbitrary accuracy.Another interesting feature of these OTCs is that they resemble time dilation in general relativity, in which two clocks measure different times under different gravitational conditions. In a similar way, OTCs create a time difference between two initially synchronized trajectories. As the scientists explain, this resemblance means that an experimenter observing an OTC system and a time dilation system might not be able to tell whether the time difference was due to the gravitational curvature of general relativity or to the trajectory of an OTC. This finding suggests that modeling gravitational time dilation as an OTC effect could have implications for a theory of quantum gravity.”Deutsch’s model describes the strange quantum effects that we might see in the presence of CTCs, within a future theory of quantum gravity,” Pienaar said. “However, if there are no CTCs in the universe, then we would not expect to see the effects. But since the slowing of time due to gravity looks just like the effect of an OTC from the outside, and since OTCs still lead to strange effects (as we have shown), we suggested that these effects might turn up in strong gravitational fields, even without any closed loops in time. If so, then they would allow us to violate the Heisenberg uncertainty principle and clone coherent states of light without needing a full-blown time machine.”Of course, the connection between OTCs and gravitational fields is still very speculative and might turn out to be wrong. We hope to flesh it out into a more complete theory in future research.”The physicists propose that testing this possibility—by testing the Deutsch model’s nonlinear effects—could be done with current technology by performing experiments on entangled systems in Earth’s gravitational field. As the scientists explain, this kind of experiment would serve as an alternative to experimenting with real OTCs, which are rather hard to come by.”The circuit itself is easy to build; it’s coming up with an OTC that’s the problem!” Pienaar said. “Strictly speaking, we would require an actual time machine in order to build that circuit, which we obviously don’t have. However, if our analogy between OTCs and gravity is correct, then we could make do with just an ordinary gravitational field like Earth’s. In that case, the circuit certainly can be built; there is already a group working on sending entangled beams of light up to a satellite in orbit. This would then provide an experimental test that could either prove or disprove our claim about gravity behaving the same as an OTC.”last_img read more

Researchers build carbon nanotube transistors that outperform those made with silicon

first_img(Phys.org)—A team of researchers at Peking University has built a carbon nanotube-based working transistor and report that it outperformed larger transistors made with silicon. In their paper published in the journal Science, the team describes how they built the transistor, how it performed and the challenges that still remain before such transistors can be mass produced. Citation: Researchers build carbon nanotube transistors that outperform those made with silicon (2017, January 20) retrieved 18 August 2019 from https://phys.org/news/2017-01-carbon-nanotube-transistors-outperform-silicon.html More information: Chenguang Qiu et al. Scaling carbon nanotube complementary transistors to 5-nm gate lengths, Science (2017). DOI: 10.1126/science.aaj1628AbstractHigh-performance top-gated carbon nanotube field-effect transistors (CNT FETs) with a gate length of 5 nanometers can be fabricated that perform better than silicon complementary metal-oxide semiconductor (CMOS) FETs at the same scale. A scaling trend study revealed that the scaled CNT-based devices, which use graphene contacts, can operate much faster and at much lower supply voltage (0.4 versus 0.7 volts) and with much smaller subthreshold slope (typically 73 millivolts per decade). The 5-nanometer CNT FETs approached the quantum limit of FETs by using only one electron per switching operation. In addition, the contact length of the CNT CMOS devices was also scaled down to 25 nanometers, and a CMOS inverter with a total pitch size of 240 nanometers was also demonstrated. © 2017 Phys.org Explore further Schematic diagram showing the structure of a GC CNT FET. Credit: (c) Science (2017). DOI: 10.1126/science.aaj1628center_img Everyone in the computer business knows the limit to which silicon-based transistors can be made smaller is drawing ever closer, so many teams around the world are searching for a suitable replacement. One of the most promising candidates is carbon nanotubes—due to their unique properties, transistors based on them could be smaller, faster and more efficient. Unfortunately, the difficulty in growing carbon nanotubes and their sometimes persnickety nature means that a way to make them and mass produce them has not been found. In this new effort, the researchers report on a method of creating carbon nanotube transistors that are suitable for testing, but not mass production.To create the transistors, the researchers took a novel approach—instead of growing carbon nanotubes that had certain desired properties, they grew some and put them randomly on a silicon surface and then added electronics that would work with the properties they had—clearly not a strategy that would work for mass production, but one that allowed for building a carbon nanotube transistor that could be tested to see if it would verify theories about its performance. Realizing there would still be scaling problems using traditional electrodes, the researchers built a new kind by etching very tiny sheets of graphene. The result was a very tiny transistor, the team reports, capable of moving more current than a standard CMOS transistor using just half of the normal amount of voltage. It was also faster due to a much shorter switch delay, courtesy of the intrinsic delay of just 70 femtoseconds.The work done by the team in China is important because it offers physical evidence that money being spent on research into carbon nanotubes as a viable replacement for silicon will indeed pay off if a way to mass produce them can be found. For first time, carbon nanotube transistors outperform silicon Journal information: Science 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

Dont let anyone take your niceness for granted

first_imgMy wife and I have no understanding. We are always fighting. I feel I should file divorce but I’m not sure whether it’s the best thing to do. When does one know that its ‘time to move on’?Name withheld, NoidaThe time when your mind and heart both believe it, when you have crossed the threshold of tolerance. When the happy moments are far lesser compared to the tears and pain accumulated. But, do go for counseling with your wife and give an honest effort to fix the marriage before you file divorce. Also Read – ‘Playing Jojo was emotionally exhausting’My mother is having an affair with one of her colleagues. My father lives out of country. I’m very upset. What should I do?Saritha, JaipurI can try and understand your feelings. But Saritha, life is never the way we plan it, it has its own plans. I suggest, you get busy with your world; there’s not much you can do by getting into this situation. If there’s something too unbearable, confront your mother and have a straight forward conversation. Being transparent usually helps. Also Read – Leslie doing new comedy special with NetflixMy grandmom lives with us. She’s very partial towards my sister as she is fair and pretty. I’m dark with no looks perhaps. How do I handle this?Tani, AgartalaDon’t lose your heart at all. If I were you, I would have gracefully avoided the partial grandmom. We are beautiful if we have a good nature. Beauty, colour, looks are all temporary factors that never determine the value of the person. Always know – ‘you are beautiful, you are the best’.My husband beats me up and rapes me every night. I’m very scared. I have a 7 year old boy. How do I live with this? Mrs. Singh, New DelhiPlease threaten him with legal consequences the next time he tries being unfair to you! Always keep the number of your local police handy and don’t hesitate to fight it out. This isn’t love, this isn’t marriage! He probably has taken your niceness for granted. Don’t keep shut and keep tolerating forever.I’m 34, single. I have had 3 failed relations. Parents insist I settle with an arranged marriage. I’m confused. I never can imagine getting married to an unknown person.Rajiv, Mumbai.Well, I suggest you go for a marriage where you select the prospect, spend quality time knowing and discovering each other and then tie the knot. ‘Arranged’ doesn’t mean someone else selects for you and you don’t have any say. Have a love or life query you cannot find an answer to? Send your questions to -roopshashotm@gmail.comlast_img read more

Five volumes on Indian languages released

first_imgThe Peoples’ Linguistic Survey of India (PLSI) here Thursday released five volumes on various Indian languages documenting their history, landmark events, folklore and songs.PLSI is a nationwide survey aimed at working out alternate ways of development of the various Indian languages and maintaining organic links between scholarship and the social context. It has planned release of 50 volumes on the Indian languages and divided them into state and national series. Also Read – ‘Playing Jojo was emotionally exhausting’The volumes released are: The Being of Bhasha: General Introduction to the People’s Linguistic Survey of India; The Languages of Assam, Assamese version; The Languages of Maharashtra, Marathi version; The Languages of Uttarakhand, Hindi version; and The Indian Sign Languages – the only volume released from the national series.Vadodara-based Bhasha Research Centre conducted the survey. The PLSI team, comprising over 3,000 activists and scholars, covered 780 languages spread across all states and union territories. Also Read – Leslie doing new comedy special with Netflix’Languages came much before the script came. So these volumes trace the origin of the language, map their history and connect them to the roots they belong to. We are on the verge of losing languages and it is important to preserve them orally,’ PLSI chairman Ganesh Devy said.He was speaking at the inaugural ceremony of a three-day event titled, ‘Mapping Indian Art, Culture and Languages’.  Lalit Kala Akademi is hosting the series of events.K.K. Chakravarty, chairman, Lalit Kala Akademi said, ‘We are trying to connect performing arts to the people through these events.”We are bringing out the volumes as they come to us,’ Ketaki Bose, associate publisher, Orient Blackswan, said.last_img read more

Putin Poroshenko discuss steps to restore peace in East Ukraine

first_imgA long-running dispute over natural gas supplies will be on the agenda when Russian President Vladimir Putin and Ukrainian leader Petro Poroshenko hold talks in Italy later this week, the Kremlin said.A Kremlin statement issued late on Tuesday said the Ukrainian and Russian presidents had spoken by telephone and discussed measures to restore peace in eastern Ukraine.They are expected to continue discussions on the conflict as well as on the gas dispute on the sidelines of a summit of European and Asian leaders they are both attending in Milan on 16 -17 October. Also Read – Pro-Govt supporters rally as Hong Kong’s divisions deepenRussian natural gas producer Gazprom cut supplies to Ukraine in June after Kiev failed to pay gas debts which Russia says have now reached more than $5 billion.Ukraine faces a possibility of energy shortages this winter if no deal is reached, risking a replay of the disruptions to Europe’s gas supplies seen in 2006 and 2009. Europe receives a third of its gas needs from Russia, and around half of it is pumped via Ukraine.Officials from Russia and the European Commission, which is mediating the talks, say a deal could be near. Poroshenko said on Saturday he hoped for ‘significant progress’ on the issue during the talks on Milan.Efforts to reach agreement have been complicated by the conflict in eastern Ukraine. Ukraine and the West accuse Russia of providing pro-Russian separatists there with extra troops and weapons, a charge Moscow denies.The conflict has caused the worst standoff in Moscow’s relations with the West since the Cold War, with the United States and the European Union having imposed sanctions on Russia over the crisis.last_img read more

Colours crafts and A concern

first_imgThe Dastkari Haat Samiti is once again gearing up for its annual display of the finest handicrafts from all corners of India at Dilli Haat, opposite INA market. The hugely popular craft bazaar has an added attraction this year- the intricate and beautiful handicrafts from Tibet, ancient craft handed down through generations of painstaking work and dedication.Hundreds of items, the best of the products of Indian and Tibetan artisans have been specially selected for the bazaar. This is also a great opportunity for the artisans to exchange their views at the Tibetan-Indian crafts and skill exchange workshop. The special feature every year is a workshop of International artisans. This time Tibetan crafts persons will engage in work with Indian counterparts from Arunachal Pradesh, Jharkhand, Uttar Pradesh and Madhya Pradesh. Also Read – ‘Playing Jojo was emotionally exhausting’Visitors will also get to enjoy the traditional music and dance. Traditional Ramdev folk singers from Kutch, Chhau dancers from Jharkhand and Tibetan traditional dancers will enrich the atmosphere throughout the day.The Dastkari Haat Samiti, now in its 29th year, is the brain child of Jaya Jaitly, who has dedicated four decades of her life and career to crafts and innovating newer ways to sustain craft and its people. She has also been a founding member of Dilli Haat, a single platform for craftsmen from the remotest areas the country to display and sell their finest wares. Jaitley said, ‘This is a unique initiative to highlight our countries rich culture and heritage. Visitors will get an opportunity to witness the vibrant colours, delicate workmanship, and respect inspiring detailing of handicrafts which have been meticulously put together’.last_img read more

18yearold found dead at home after school denies promotion

first_imgKolkata: Mystery shrouds the death of an 18-year-old girl whose body was found inside her house in Habibpur area of Ranaghat in Nadia.According to a preliminary investigation, police suspect that the victim, Sweta Sahu might have committed suicide by consuming poison. She was declared brought dead after being taken to a private nursing home in the district. She was a student of XI from Brajabala Girls’ High School in Nadia.The victim’s family members alleged that she suffered from mental depression as she was not promoted to class XII Also Read – Heavy rain hits traffic, flightsafter she failed to appear for Geography practical examination. They also alleged that the school headmistress rebuked her. The school authorities called her on her cell phone on the day of practical examination but she did not answer. According to the school authorities, neither the student nor her family members informed the school about her not appearing for the examination.A few days ago, the girl and her family members went to the school headmistress and urged her to allow Sweta to the next class. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe headmistress did not, however, agree to promote her to the next class. The family members told police that the victim went into depression after the school authorities denied her promotion. She went into her room on Saturday evening and consumed poison. Her family members found her lying still in her bed. She was immediately rushed to a private nursing home at Ranaghat, where the doctors pronounced her brought dead. Following the incident, the girl’s family members lodged a complaint against the school headmistress at Ranaghat police station. Police have started a detailed probe in this regard.The school authorities have, however, expressed their grief over her death. They also claimed that they tried to contact the victim and her family members but none responded. She was not promoted to class as she did not appear the examination, school authorities claimed.last_img read more

Speeding truck runs over youth on BongaonBagda Road

first_imgKolkata: A youth was killed after being knocked down by a speeding truck. The incident took place near Dharma Pukuria area on Bongaon-Bagda Road on Friday morning.The incident led to chaos after some locals staged a demonstration at the place of the incident protesting against the reckless driving of vehicles. The incident also caused traffic disruption on Bongaon-Bagda Road for almost an hour.Police said the victim, Debojyoti Chakraborty (30), a resident of Halencha area of Bagda was going to his workplace along the Bongaon-Bagda road. He was passing through the Dharma Pukuria area at around 9 am on Friday when a loaded truck hit his motorcycle. Also Read – Rain batters Kolkata, cripples normal lifeAs the truck was at a high speed, the biker fell at a distance with his bike. The truck driver fled the spot along with the vehicle immediately after the accident.Although the victim was wearing helmet, the impact of the accident was so high that he received multiple injuries.The locals rushed to the spot and took the injured victim to hospital where the doctors pronounced him brought dead. According to the district police, Chakraborty received critical injuries on his chest, abdomen and head. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedAccording to the preliminary investigation, police came to know that the truck was overloaded.The eyewitnesses told the police that truck was headed towards Bongaon when the accident took place.Police suspect that the truck had moved towards the left side of the road after the truck driver saw the branches of a tree at a distance when the accident occurred. The agitation was later lifted following the intervention of senior police officers from the district.Police have started a probe in this regard. The victim’s body was sent for an autopsy. Raids are being conducted to nab the truck driver.last_img read more