New interferometer could simplify materials research

first_img Explore further “We can get an interferometer that is more in line with classical visual optics,” Snigirev says. An interferometer works when beams of light are sent through slits or lenses, and patterns are detected against a background on the other side. The patterns reveal information about the object of study. “Our technique is sensitive enough for diagnostics and accurate measurements, and is more stable and easier to set up than using crystals.” Information on the work done by Snigirev and his colleagues is found in Physical Review Letters: “X-Ray Nanointerferometer Based on Si Refractive Bilenses.”Using electron beam lithography, the lenses used by Snigirev and his peers were created by a process of deep reactive-ion etching into silicon. “We prepared concave lenses, and put them in a row. This inline approach increases the refraction power,” Snigirev explains. “Varying the number of individual lenses it is possible to focus x-rays at different distances from meter to milimeter focus distance and use this technique for nano-focusing.”Rather than relying on double slit-type interferomter, which is difficult to accomplish and because of low resolution and loss of intensity, this team relied more on an interferometer related to the Billet split lens. In this classical optics technique, a lens is cut along the optic axis. This still allows for interference to be measured, but the intensity remains high, and the resolution is better.Snigirev points out that one of the advantages of this system is that it is tunable. . “You can tune this ‘nanoruler’ system easily by changing x-ray energy or by moving objects along the optical axis.” Another advantage of the system is in the silicon construction of the lenses. “Silicon is very stable,” Snigirev explains. “It can also take a high heat load, as from a beam. In this case we are using x-rays, but it could be used for future X-ray Free-Electron laser projects.”Indeed, the possible future applications of this interferometer set up have promise. “This could be very attractive for materials research,” Snigirev insists. “It would allow us a better look at photonic and colloidal crystals, multilayer structures, as well as other natural and synthetic mesoscopic materials”.“Interferometry is used a great deal right now, and it could be improved for research into materials and also for other purposes. It is a very important technique,” Snigirev continues. “However, as it is done now it can be difficult to implement. Our approach is simpler, and it could really help in the development of future applications and materials development.”More Information: A. Snigirev, et. al., “X-Ray Nanointerferometer Based on Si Refractive Bilenses,” Physical Review Letters (2009). Available online: http://link.aps.org/doi/10.1103/PhysRevLett.103.064801. Copyright 2009 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. 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. Fabricating 3D Photonic Crystalscenter_img Citation: New interferometer could simplify materials research (2009, August 13) retrieved 18 August 2019 from https://phys.org/news/2009-08-interferometer-materials.html (PhysOrg.com) — “Most current hard x-ray interferometers are based on crystals, which require their high quality and high mechanical stability,” Anatoly Snigirev tells PhysOrg.com. “This can make x-ray interferometry quite limited. What we have done is develop a different set up that is simpler.” Snigirev is a scientist at ESRF in Grenoble France. Along with scientists at the Russian Kurchatov Research Center in Moscow, and at IMT RAS in Chernogolovka, Russia, Snigirev proposes that refractive bilenses made from silicon can be used in place of crystals.last_img read more

Antarctic lake home to diverse community of viruses

first_img Aquatic viruses usually infect prokaryotes such as bacteria, but the viruses in the Antarctic had a large proportion of viruses that infect eukaryotes. The findings included small single stranded DNA (ssDNA) viruses and phycodnaviruses that have never previously been seen in aquatic environments. The researchers, Alberto Lopez-Bueno and colleagues, from Spain and the UK, examined samples taken from Lake Limnopolar on Livingston Island in the Antarctic before and during the summer, and found the aquatic environment to be rich in microorganisms and a diverse collection of viruses that prey on them. The number of viral genotypes found was unusually high, running into thousands instead of the more usual hundreds, and less than 3 percent of the genome sequences were similar to previously identified viral genomes from aquatic systems. Many of the ssDNA viruses were related to non-aquatic viruses that infect plants, mammals and birds, and some had never been found in aquatic environments before.The scientists also observed a change in the virus assemblage with the seasons. When the lake was covered in ice during spring, the smaller single strand DNA viruses dominated, while in summer, when the lake was open, the larger (>50 nanometer) double-stranded DNA viruses dominated, possibly because of seasonal differences in the host organisms, such as the algal blooms that appear in summer.The scientists also found the double-stranded DNA viruses helped the bacteria survive by assisting their metabolism of amino acids and carbohydrates, and helping with respiration.Antarctic lakes are covered with ice for around nine months of the year, and the underwater environment is cold, dark, and contains few nutrients, and is home to bacteria, protozoa, algae and viruses, and little else. In these conditions viruses probably play an important part in controlling the other microbes.Viruses from Antarctica have been difficult to study in the past because they cannot be grown in the laboratory, but new genome sequencing technologies are allowing researchers to identify viruses without the need to grow them.The research paper is published in the November issue of Science.More information: High Diversity of the Viral Community from an Antarctic Lake, Science 6 November 2009: Vol. 326. no. 5954, pp. 858 – 861; DOI: 10.1126/science.1179287© 2009 PhysOrg.com Antarctic lake. Image credit: British Antarctica Survey. Explore further (PhysOrg.com) — A study of the genetic structure of viruses in an Antarctic lake has revealed an astonishing genetic richness in the large number of viral families discovered. In Brief: Mobile viruses doubled since Nov. 05 Citation: Antarctic lake home to diverse community of viruses (2009, November 11) retrieved 18 August 2019 from https://phys.org/news/2009-11-antarctic-lake-home-diverse-viruses.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

Encrypted VoIP not as secure as it sounds

first_img Stop Big Brother listening in to your mobile phone conversation More information: Phonotactic Reconstruction of Encrypted VoIP Conversations: Hookt on fon-iksAbstractIn this work, we unveil new privacy threats against Voice-over-IP (VoIP) communications. Although prior work has shown that the interaction of variable bit-rate codecs and length-preserving stream ciphers leaks information, we show that the threat is more serious than previously thought. In particular, we derive approximate transcripts of encrypted VoIP conversations by segmenting an observed packet stream into subsequences representing individual phonemes and classifying those subsequences by the phonemes they encode. Drawing on insights from the computational linguistics and speech recognition communities, we apply novel techniques for unmasking parts of the conversation. We believe our ability to do so underscores the importance of designing secure (yet efficient) ways to protect the confidentiality of VoIP conversations. Citation: Encrypted VoIP not as secure as it sounds (2011, May 26) retrieved 18 August 2019 from https://phys.org/news/2011-05-encrypted-voip.html The results of the team’s efforts show that services such as Skype, even though they use both encoding (converting words to code or data) and encryption (transforming the encoded messages to a different form using an algorithms) techniques to prevent easy capture of voice conversations over the Internet, are vulnerable to eavesdropping by perpetuators bent on listening in on what are supposed to be private conversations.The team was able to reconstruct conversations, not by beating the encryption scheme, but by measuring the data packet size of messages sent electronically across a network and then by applying known linguistic rules of human speech to those packets to decipher individual components of speech, which when put together, resulted in conversations that were at times, able to be understood by those listening.In the paper that accompanied their presentation, the team describes the process as similar to that used by infants when learning to communicate. They learn by associating certain words they hear over and over with known results. When an adult speaks to them, they parse out the stuff they don’t understand and instead concentrate on the words that stand out that they do know; linguists use the term “well formed” to describe terms that are understandable amongst those that are not. Infants use well formed phrases to help them deduce the meaning of other words that surround the ones they do know to try to figure out what is being said; a process the research team essentially duplicated when trying to recreate phone conversations.Because the results varied widely, and because eavesdroppers would need a lot of time, talent and money to recreate the results the team found, current users of such services shouldn’t worry that someone is listening in, but even so, now that a vulnerability has been exposed, it’s likely that Skype and other VoIP providers will take steps to eliminate the newly discovered weakness. Explore further (PhysOrg.com) — Linguistics researchers working with computer scientists at the University of North Carolina have shown that voice conversations over the Internet, even if they are encrypted, are not as secure as generally thought. Presenting their findings at the IEEE Symposium on Security and Privacy in Oakland California this past week, the team showed that by breaking up voice messages broadcast over the Internet, and then parsing the bits into phonemes (human speech components) they could, using linguistic rules, essentially recreate conversations; at least to some degree. The results varied, but were in general good enough to gain the essence of what was being said. 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. Overall architecture of our approach for reconstructing transcripts of VoIP conversations from sequences of encrypted packet sizes. Image credit: Andrew M. White. © 2010 PhysOrg.comlast_img read more

Apple granted smartphone touchscreen patent

first_img The patent, which was filed over three years ago, is specific to capacitive touchscreen technology. The patent is worded like this: “[a] computer-implemented method, for use in conjunction with a portable multifunction device with a touch screen display, [that] comprises displaying a portion of page content, including a frame displaying a portion of frame content and also including other content of the page, on the touch screen display.” This means that the patent could literally refer to any screen with a multi-touch interface.The current generation of capacitive touchscreen displays work with a sheet of glass, which uses the human finger as a conductor. This input, a.k.a. your touch, then creates a response from your device. The way that this patent has been worded it could refer to any screen that has a multi-touch interface. This could allow Apple to either squeeze competitors out of the market or to make them pay hefty fees in order to keep making their smart phones or tablet PCs that use the extremely popular multi-touch technology. Of course, it could go in a different direction, with Apple only using the patent as a means to defend their own technology, but only time will tell how it will be used. Apple does, like most major technology companies and hardware makers indulge in the occasional lawsuit over the infringement of patents as a way of thinning the competition and making some fast cash. © 2010 PhysOrg.com Explore further (PhysOrg.com) — Apple was recently awarded a patent that has the potential to have repercussions across the world of smart phones and tablet PCs. Citation: Apple granted smartphone touchscreen patent (2011, June 22) retrieved 18 August 2019 from https://phys.org/news/2011-06-apple-granted-smartphone-touchscreen-patent.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. Taiwan firm accuses Apple of patent infringementlast_img read more

Bell correlations measured in half a million atoms

first_imgIllustration of a squeezed spin state used to demonstrate Bell correlations. Credit: Engelsen et al. ©2017 American Physical Society Natural systems show nonlocal correlations Citation: Bell correlations measured in half a million atoms (2017, April 17) retrieved 18 August 2019 from https://phys.org/news/2017-04-bell-million-atoms.html Journal information: Physical Review Letters The researchers, led by Mark Kasevich at Stanford University, have published a paper on the large system exhibiting Bell-type quantum correlations in a recent issue of Physical Review Letters.”Our results illustrate the richness of quantum many-body states involving many entangled systems,” Kasevich told Phys.org. “Little is known at this frontier.”In order to use quantum correlations for practical purposes, the correlations must be measured. Until recently, the only way to measure Bell correlations in a system of atoms (or other components) was to measure the correlations between all of the individual atoms. But a few years ago, physicists developed a new method of measuring Bell correlations that does not require measuring individual components, but can be done by measuring the collective properties of the system as a whole. Last year, scientists used this method to demonstrate Bell correlations in a Bose-Einstein condensate of around 500 atoms.In the new study, the researchers have increased this number to a record 500,000 atoms. To do this, they used a method called spin squeezing, in which they started by preparing all of the atoms’ spins in a superposition of up and down states. The researchers then reduced (or “squeezed”) the uncertainty of one spin component below the value allowed for uncorrelated atoms, which simultaneously increases the uncertainty of the conjugate spin component to satisfy the uncertainty principle. By making collective measurements on the spin properties of the entire system, the researchers demonstrated that the spin states exhibit correlations beyond what is expected by classical physics. Currently, it’s unclear exactly how nonlocal Bell correlations may be used in such large systems. In smaller systems, Bell correlations have been used to generate random numbers, which have applications in cryptography. The physicists also expect that the experimental methods used here could be used to test the predictions of quantum theory.”We hope to test quantum mechanics in news ways with spatially extended versions of the states used in this work,” Kasevich said. “Imagine a quantum many-body state extending over one meter involving thousands of correlated particles. The squeezed states used for this work also have practical application in sensors, as they can be exploited to reduce sensor noise.” More information: Nils J. Engelsen, Rajiv Krishnakumar, Onur Hosten, and Mark A. Kasevich. “Bell Correlations in Spin-Squeezed States of 500 000 Atoms.” Physical Review Letters. DOI: 10.1103/PhysRevLett.118.140401center_img (Phys.org)—Physicists have demonstrated Bell correlations in the largest physical system to date—an ensemble of half a million atoms at an ultracold temperature of 25 µK. The presence of Bell correlations indicates that all of the atoms share nonlocal quantum correlations with each other. These correlations could one day be used in quantum information systems and to design new tests of quantum mechanics. © 2017 Phys.org Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Trend Alert Crop it

first_imgReplay the Lucky Song by Madonna that caused a controversy about ‘crop tops’; newly known as the midriff exposure, is simply rewinding the 80s style. From pop artists to television celebs to super stars, all are in saga with showing off their taut tummies. Some of the artists sporting the crop top look include Rihanna, Frieda Pinto, Sonam Kapoor and Hilary Rhod.For Indian’s, crop top is the next step forward from the typical traditional wear ‘choli’. A few ways to style the crop top right are: Also Read – ‘Playing Jojo was emotionally exhausting’Team the crop top with high-waist jeans, shorts or skirts, so you reveal less but still look stylish.  Go flirty with tying a shirt up at the front with a high waist skirt or jeans.  For those chicas who like to play safe, team your crop top with a fitted tank underneath andgo trendy. You can also go formal by teaming the midriff with snazzy pants and a groovy jacket. Beat the heat with these and add the gaga to your daily parade. As the crop top is topping the field all the way, a few curated pieces can be found at a clothing website called Miss Chase (http://www.misschase.com). A UK fashion brand made affordable for the first time ever.  Just flaunt it if you have it! Now’s a good time to tone that tummy and pick a colour and cut that works for you – and you will be all set to make heads turn.last_img read more

Going back in time

first_imgDo you have thoughts popping up in your head– Am I happy? Why can’t I feel the happiness from within? Why there is constant pain in my leg or any other part of the body? Why my relationships don’t work? Why am I constantly fighting with my parents? Why am I not able to earn enough money? These are few questions that often come to our mind but we really don’t know the reasons behind them. The reason can be the memories that one is carrying from their past lives. Past life Regression therapy takes a person back to one of his/her past lives while being in a hypnotised state and lets them experience it once again to resolve the problem that he/she facing in the present. It helps us to get into the root cause of the problem to resolve it at physical, mental and emotional level. Past Life Regression Therapy is based on the principles of cause and effect which is commonly known as ‘Karma’ and this is catching up in our country as well through the process of holistic healing. People choose to explore their past lives for many reasons. It can be a source of self discovery and clarity, to find life’s direction and purpose. It may be to understand relationships; an intense attraction or aversion; the origin of fears, guilt and anger. There is insight into health and emotional issues; one may gain an increase in confidence by re-experiencing a happy, successful lifetime. Also Read – ‘Playing Jojo was emotionally exhausting’All hypnosis is self-hypnosis, including past life regression. It is a voluntary state of mind with a very relaxed, focused concentration and a heightened sense of recall. During the hypnosis or past life regression session one is actively aware and always in control. None can ‘program’ you or make you do or say anything that goes against your desires or beliefs. Before a session, one should discuss thoughts and goals with the hypnotist to find areas of exploration for your hypnosis or past life regression session or the session can be left open to one’s inner guidance to bring forth memories and lives pertinent to your current life. As your guide, the hypnotist assists you on this journey so you may discover and re-experience significant events, situations, relationships and skills, both in this life and past lives. Also Read – Leslie doing new comedy special with NetflixMore than half the world’s population believe in reincarnation (past lives) – that we have all lived, died and lived again many times. A great sense of serenity comes from knowing that the deepest parts of ourselves, the soul consciousness, survives physical death and will always exist. Through this process, we are given many opportunities to learn and master the lessons of life on Earth – what many call Karma.Where to go : Dr. Kumar’s Homeopathy & Mental Health ClinicAdd. 585, GF, J. P. Complex, Bank Street, Munirka, New DelhiDr.Rashmi Joshi Psychologist Psychological Aura, Quality Wellness Clinic Delhilast_img read more

Shoaib Akhtars advice worked for me Shami

first_imgCrediting Shoaib Akhtar for bringing back rhythm in his bowling, Indian pacer Mohammed Shami has said the former Pakistan speedster advised him to shorten his run-up, which has helped him increase his pace.“The recent change in run-up has surely increased my pace. So I am continuing with it and hoping that it pays rich dividends. I did have a chat with Shoaib (Akhtar) bhai and he suggested that I should reduce my big strides. So shortened my stride and it has worked. It (the new run-up) is smooth and comfortable and it has also increased my pace,” Shami said. Also Read – Khel Ratna for Deepa and Bajrang, Arjuna for JadejaShami, who returned to action against West Indies after missing a game due to a niggle, bagged three wickets at the WACA to help table-toppers India register their fourth straight win and book a quarterfinal berth from pool B. With the Men in Blue now in New Zealand for their final two games of the league, Shami is keen to carry on the good work without making any more changes to his action. “I don’t want to change much in my action. And most of the ex-players have advised me against making any major changes to my action. It is always a double edged sword, to change one’s action. It can work for you or go against you. I don’t want go through this confusion and I am satisfied with the little change that I have made to my run-up,” I do not want to make much changes to my action or strategy in New Zealand as well,” he said.last_img read more

Post poll clashes rock Bengal

first_imgKolkata: After 12 persons were killed in widespread violence during the West Bengal Panchayat election a day ago, post poll clashes continue to rock parts of the state on Tuesday. The state administration, however, claimed only six of those deaths were poll-related, State Election Commission (SEC) said.”According to the report received from the state administration, 12 deaths are reported on the polling day on Monday. Among them six are poll-related deaths, while the rest were due to different reasons,” SEC Secretary Nilanjan Shandilya told IANS. Also Read – Heavy rain hits traffic, flightsPost poll violence was reported from parts of Howrah district where bombs were hurled in at least 20 houses during a clash between Trinamool Congress workers and BJP activists. A few vehicles were also vandalised and torched.Sporadic incidents of violence took place in South and North 24 Parganas and Nadia districts late on Monday.The single-phase rural polls in the state on Monday saw large scale violence and clashes between opposing political outfits throughout the day even as more than 60,000 armed personnel and 80,000 civic volunteers were deployed to guard close to 58,000 polling booths. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedAs the day progressed, reports of clashes, booth capturing, vandalising of ballot boxes and rigging were received from pockets of South and North 24 Parganas, North Dinajpur, Nadia, West Midnapore and Cooch Behar districts.In several places, gun-toting goons attacked policemen on duty at polling premises, leaving at least two police officers severely injured. Several attempts to rig the election process were also reported across the state as miscreants poured water into ballot boxes or set them on fire. Additional Director General of West Bengal Police Anuj Sharma on Monday said Trinamool activist Arif Ali Gazi died in poll-related violence in South 24 Parganas while two other workers of the party died in Nadia. He said two Communist Party of India-Marxist (CPI-M) workers died in Nandigram in East Midnapore district and a Jharkhand Disom Party worker died in Kushmundi of South Dinajpur.The opposition parties accused the Trinamool Congress of orchestrating unprecedented terror on the polling day and alleged the SEC and state administration completely failed to conduct a free and fair election.Representatives of CPI-M held a protest demonstration outside the SEC office on Monday evening demanding an answer from the poll panel about the adverse situations across the state.The state’s ruling Trinamool Congress, however, claimed that the people were able to exercise their democratic rights and said the situation was well handled barring a few isolated incidents.It accused the Bharatiya Janata Party of bringing in people from Bangladesh, Assam and Jharkhand with the help of Border Security Force personnel on the polling day to create unrest.Voting for the rural bodies in West Bengal was to be held on May 1, 3 and 5, but as the nomination process started in April, it was rescheduled to May 14 by the SEC following a Calcutta High Court order to extend the nomination deadline and announce a fresh polling date.last_img read more

City police chief visits college amid allegations of extortion

first_imgKolkata: Amidst complaints of extortion from students for admission to colleges, Kolkata Police Commissioner Rajeev Kumar today visited a college in central Kolkata and spoke to the students and guardians. Kumar went to the Surendranath College in Sealdah area and interacted with students and guardians to know if they are facing any problem regarding getting admission in colleges. Police stations both in the city and districts have been asked to keep a tab on the colleges in their respective areas and take action if there are complaints of extortion, a police official said. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killed Both the police and the state education department have been receiving complaints of irregularities as several students and guardians have alleged that money was demanded from them in lieu of admission in colleges. Education Minister Partha Chatterjee yesterday said some outsiders are involved in the extortion and the government will identify them and take action. West Bengal Chief Minister Banerjee, who paid a sudden visit to her alma mater Ashutosh College in south Kolkata on Monday, said the merit list will be the only criteria for admission to colleges. Also Read – Naihati: 10 councillors return to TMC from BJP Several persons have been arrested in connection with the alleged extortion. Chatterjee, who also had visited two colleges, asked the students to pay the admission fees to the colleges through banks if their names featured in the merit list. The Kolkata Police on Saturday posted a message on its Facebook page, urging students to inform the police if someone demands money for admission to colleges. The post said the identity of the complainant would be protected.last_img read more