Copyright 2010 PhysOrg.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. More information: G. Goldstein, et al. “Environment-Assisted Precision Measurement.” Physical Review Letters 106, 140502 (2011). DOI:10.1103/PhysRevLett.106.140502AbstractWe describe a method to enhance the sensitivity of precision measurements that takes advantage of the environment of a quantum sensor to amplify the response of the sensor to weak external perturbations. An individual qubit is used to sense the dynamics of surrounding ancillary qubits, which are in turn affected by the external field to be measured. The resulting sensitivity enhancement is determined by the number of ancillas that are coupled strongly to the sensor qubit; it does not depend on the exact values of the coupling strengths and is resilient to many forms of decoherence. The method achieves nearly Heisenberg-limited precision measurement, using a novel class of entangled states. We discuss specific applications to improve clock sensitivity using trapped ions and magnetic sensing based on electronic spins in diamond. The researchers, Garry Goldstein from Harvard University, along with coauthors from Harvard, MIT, Copenhagen University, and the California Institute of Technology, have published their study called “Environment-Assisted Precision Measurement” in a recent issue of Physical Review Letters. In their study, the scientists first describe an idealized case, and then demonstrate that it works in two different cases: quantum clocks with trapped ions and spin-based magnetometry.“We realized that part of the environment can be used to increase sensitivity,” coauthor Paola Cappellaro of MIT told PhysOrg.com. “We found that entangled states, other than the ones usually proposed for metrology (GHZ states, squeezed states) can improve the sensitivity while being more robust to decoherence.”As the scientists explain, a quantum sensor can be constructed with a central spin coupled to a bath of dark spins, which are part of the environment. All of these spins act as qubits, each having a state of 0, 1, or a superposition of both. While the central spin can be controlled and read out, the dark spins can only be collectively controlled and not directly detected. Also, the central spin and the dark spins can be coupled, and this coupling can be effectively turned on and off at will.The central spin can indirectly measure the external field, such as a magnetic field, by sensing the dynamics of the surrounding dark spins, which are in turn affected by the external field. To do this, the researchers first entangled the central spin to the dark spins, and then used this entangled state to sense the external field. As the entangled dark spins evolve, they acquire a phase that depends on the state of the central spin. Then, the researchers could flip the central spin and read out its signal. By reading this signal, the researchers could measure the phase difference between the states of the dark spins, which provides a measurement of the external field.Importantly, the additional phase difference due to the dark spins amplifies the signal of the central spin and allows it to read out a smaller field than before; the smaller the field that a sensor can read out during a given time, the higher its quantum sensitivity. While the signal is enhanced, the background noise stays the same.“Here we assume that part of the environment (the ‘dark spins’) can be controlled, although it cannot be directly measured,” Cappellaro said. “In this scenario, there are two possible strategies: manipulate the environment dark spins to decouple them from the sensor or exploit them by creating an entangled state with the sensor spin. We found that this second strategy is viable and yields better sensitivity.”Overall, the method achieves precision that approaches the Heisenberg limit. This limit results from the Heisenberg uncertainty principle and marks the maximum sensitivity that any measurement can achieve.When comparing this method to another measurement precision procedure based on a spin-echo, the researchers found that the new method has greater sensitivity due to the central spin’s signal amplification. Both methods have about the same coherence times, since, for both methods, decoherence arises from interactions among dark spins, not the rest of the environment.As the simulations demonstrated, the new method could have applications in improving clock sensitivity using trapped ions and magnetic sensing based on electronic spins in diamond. The scientists also predict that this method could be applied more generally to a wide variety of systems.“Extremely sensitive clocks are very important, for example, for global positioning,” Cappellaro said. “Magnetic sensors could find applications in a broad range of areas, from materials science to bio-imaging.” Explore further Creating a pure spin current in graphene Citation: Sensitivity of precision measurements enhanced by the environment (2011, April 27) retrieved 18 August 2019 from https://phys.org/news/2011-04-sensitivity-precision-environment.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. (PhysOrg.com) — When it comes to quantum measurements, interaction with the environment usually limits sensitivity, since it causes decoherence. But in a new study, scientists have shown that the environment can be advantageous. They have designed a method to increase the sensitivity of quantum precision measurements by using the environment to enhance a quantum sensor’s response to weak perturbations in an external field. A model of a central spin coupled to a spin bath of dark spins, which are part of the environment. By sensing the dynamics of the dark spins, the central spin has a greater sensitivity that allows it to read out smaller external fields, such as magnetic fields. Image credit: G. Goldstein, et al.
More information: Stick–slip advance of the Kohat Plateau in Pakistan, Nature Geoscience (2012) doi:10.1038/ngeo1373AbstractThroughout most of the Himalaya, slip of the Indian Plate is restrained by friction on the interface between the plate and the overlying wedge of Himalayan rocks. Every few hundred years, this interface—or décollement—ruptures in one or more Mw ≥8 earthquakes. In contrast, in the westernmost Himalaya, the Indian Plate slips aseismically beneath wide plateaux fronting the Kohistan Mountains. The plateaux are underlain by viscous décollements that are unable to sustain large earthquakes1. Potwar, the widest of these plateaux is underlain by viscous salt2, 3, which currently permits it to slide at rates of about 3 mm yr−1 (refs 4, 5), much slower than its 2 Myr average6, 7. This deceleration has been attributed to recently increased friction through the loss of salt from its décollement. Here we use interferometric synthetic aperture radar and seismic data to assess movement of the Kohat Plateau—the narrowest and thickest plateau8, 9. We find that in 1992 an 80 km2 patch of the décollement ruptured in a rare Mw 6.0 earthquake, suggesting that parts of the décollement are locally grounded. We conclude that this hybrid seismic and aseismic behaviour represents an evolution of the mode of slip of the plateaux from steady creep towards increasingly widespread seismic rupture. © 2011 PhysOrg.com (PhysOrg.com) — The media (and school teachers, of course) has done a very good job of informing most people about how earthquakes work. We can all very easily imagine two great plates rubbing against one another, like two fists rubbing together, creating havoc along fault lines. But what most of us have never likely imagined is the type of earthquake that occurred back in 1992 in Kohat, Pakistan. Explore further Instead of two plates rubbing together, a whole section of the earth simply moved from one place to another, like a rug being pulled out from underneath those that were living there. In some ways, it appears the quake was more like a giant mud slide than a normal earthquake. It’s only now, twenty years later, that scientists have put the pieces together though. S. P. Satyabala, Zhaohui Yang and Roger Bilham, as they describe in their paper published in Nature Geoscience, have found using satellite radar and historical seismic data, that the 6.0 quake was in fact a rare horizontal one.Such quakes occur, the researchers say, when a parcel of land sits atop another with something that works as a slippery agent between them. In this case, the team believes it’s a layer of salt. What happens is, a whole swath or slip of land is very, very slowly moving downhill, like a glacier. In this case, the rate is about one to two millimeters each year; so slowly that the movement is not noticed by those that are living on the land above. Unfortunately, it’s not always such a smooth ride. Every now and then, something causes a problem with the slippery layer, resulting in the upper and lower rock touching. Without the slippery stuff between them, the two layers of land stop sliding, but only for awhile as the forces that caused the top part to slide in the first place, continue to work. Eventually, the top layer gives way and lurches forward, causing a very noticeable earthquake. In 1992, over 200 people were killed as buildings fell on top of them.To come to their conclusions the team turned to interferometric synthetic aperture radar, which is a method of data collection via satellite that maps the surface of the Earth over time. In this case, when that data was combined with seismic recordings, it was easy for the team to see that some 3,800 square miles of land surrounding Kohat, had shifted about a foot, all at once.Unfortunately for those that live there, it appears that such an occurrence will likely happen again, though at least now they will have more knowledge about what is going on beneath them and thus will be able to make more informed decisions going forward. Scientists Expose ‘Buried’ Fault that Caused Deadly 2003 Quake in Iran Journal information: Nature Geoscience A North-south cross section passing through the Kohat earthquake showing the decollement and (south-dipping) faults branching upwards. Image: Nature Geoscience (2012) doi:10.1038/ngeo1373 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: New research shows 1992 earthquake in Pakistan was due to rare horizontal shift (2012, January 16) retrieved 18 August 2019 from https://phys.org/news/2012-01-earthquake-pakistan-due-rare-horizontal.html
Citation: Spinoff to introduce ultrasonic gesture recognition for small devices (w/ Video) (2013, November 1) retrieved 18 August 2019 from https://phys.org/news/2013-11-spinoff-ultrasonic-gesture-recognition-small.html Recognizing that devices are getting smaller, including their screens, of course, the researchers began looking into ways users might be able to use gesture recognition, instead of physically touching a device to give it commands (waving a hand in the air above it, rather than swipping the screen, for example). They found that using light as a medium required bulky equipment and would only work in optimal situations. That caused them to turn to studying sound as a means of sending information instead. That in turn led to the development of two computer chips, one is an ultrasound chip, the other is a chip that sends and receives electrical signals from the ultrasound chip. A third component is a battery. The system works by generating sound wave pulses using a very tiny array of sound transducers (speakers). The chip then listens to the pulses when they are bounced back. Doing so allows the chip to calculate how far away something is, just like radar. Even better, the new technology uses just a fraction of the power of light based systems, and it’s small enough to be embedded in even the smallest devices, such as smartwatches.Gesture recognition technology would be ideally suited to both smartwatches and headsets, allowing for new types of movement to be incorporated into a command set. Simply drawing the wrist towards the face, could for example, activate a smartwatch. Also, wiping the air in front of a headset, such as Google’s could allow for swiping virtual objects. That might be good news for both devices, as thus far, consumers haven’t been very receptive to either. Making them less awkward to use, could mark a turning point, causing the development of all manner of tiny niche devices such as smartnecklaces, fobs or even tiny smartscreens embedded in contact lenses. Elliptic Labs develops ultrasonic gesture control for hand-held devices (Phys.org) —A group of research engineers at the University of California has been working on new technology to allow electronic devices to recognize hand gestures, similar to Microsoft’s Kinect—with a major difference. Instead of using light, the new technology is based on sound waves. The group is currently forming a spinoff company to develop and market the technology, called Chirp Microsystems (the technology itself is called simply Chirp). 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. Optical 3D imagers for gesture recognition, such as Microsoft Kinect, suffer from large size and high power consumption. Their performance depends on ambient illumination and they generally cannot operate in sunlight. These factors have prevented widespread adoption of gesture interfaces in energy- and volume-limited environments such as tablets and smartphones. Gesture recognition using sound is an attractive candidate to overcome these difficulties because of the potential for chip-scale solution size, low power consumption, and ambient light insensitivity. Our research focuses on building an ultrasonic 3D range sensor system suitable for gesture recognition using batch-fabricated micromachined aluminum nitride (AlN) ultrasonic transducer arrays and custom CMOS electronics. © 2013 Phys.org Explore further More information: swarmlab.eecs.berkeley.edu/swarmlab.eecs.berkeley.edu/new … al-gestures-interact
More information: Sarah Marshall-Pescini et al. Importance of a species’ socioecology: Wolves outperform dogs in a conspecific cooperation task, Proceedings of the National Academy of Sciences (2017). DOI: 10.1073/pnas.1709027114AbstractA number of domestication hypotheses suggest that dogs have acquired a more tolerant temperament than wolves, promoting cooperative interactions with humans and conspecifics. This selection process has been proposed to resemble the one responsible for our own greater cooperative inclinations in comparison with our closest living relatives. However, the socioecology of wolves and dogs, with the former relying more heavily on cooperative activities, predicts that at least with conspecifics, wolves should cooperate better than dogs. Here we tested similarly raised wolves and dogs in a cooperative string-pulling task with conspecifics and found that wolves outperformed dogs, despite comparable levels of interest in the task. Whereas wolves coordinated their actions so as to simultaneously pull the rope ends, leading to success, dogs pulled the ropes in alternate moments, thereby never succeeding. Indeed in dog dyads it was also less likely that both members simultaneously engaged in other manipulative behaviors on the apparatus. Different conflict-management strategies are likely responsible for these results, with dogs’ avoidance of potential competition over the apparatus constraining their capacity to coordinate actions. Wolves, in contrast, did not hesitate to manipulate the ropes simultaneously, and once cooperation was initiated, rapidly learned to coordinate in more complex conditions as well. Social dynamics (rank and affiliation) played a key role in success rates. Results call those domestication hypotheses that suggest dogs evolved greater cooperative inclinations into question, and rather support the idea that dogs’ and wolves’ different social ecologies played a role in affecting their capacity for conspecific cooperation and communication. (Phys.org)—A team of researchers from the Wolf Science Center and the Comparative Cognition, Messerli Research Institute, both part of the Medical University of Vienna, has found that packs of wolves behave more cooperatively among themselves than do groups of dogs. In their paper published in Proceedings of the National Academy of Sciences, the group describes how they tested both groups of animals at their research institute and what they found by doing so. As the researchers note, the consensus among scientists is that dogs are more social than wolves because they have been bred over multiple generations to be social with humans. But do those social skills apply to cooperation with other dogs? That was the question that motivated the researchers to set up an experiment to compare the two groups in a contrived social setting.To test the degree of cooperation of members of a wolf pack or group of dogs, the researchers set up an apparatus that allowed two animals to work together to gain access to a food reward. To obtain a bowl of food, both animals had to tug on separate ropes at the same time—in short, they had to cooperate for the benefit of both.The researchers ran the experiment hundreds of times with multiple pairs of dogs and wolves and then tallied the results. They found that dogs were not good at cooperating to gain a meal—out of 472 tries, the dogs succeeded in getting their reward just two times. The wolves, on the other hand, were much better, getting their reward 100 times out of 416 tries.The researchers noted that the wolves did best when paired with familiar partners that also held the same “rank” in the pack. In watching how the animals went about their task, the researchers found that the wolves were much more willing to approach the food bowl together, rather than one waiting for the other. With dogs, the researchers note, the one that is dominant usually goes first, otherwise fighting erupts. The researchers suggest that by approaching the bowl together, the wolves were able to see more clearly what needed to be done to get their food reward.The researchers suggest that while dogs have clearly learned to be more social and cooperative with humans over the years, they appear to be less so with other dogs. Journal information: Proceedings of the National Academy of Sciences Sensitivity to inequity is in wolves’ and dogs’ blood wolves working at a cooperative rope-pulling test. Credit: Rooobert Bayer (Wolf Science Center, Ernstbrunn, Austria).
It was an elite gathering, which had come to see the paintings and sculptures of the well known painter and sculptor, Renuka Sondhi Gulati at Triveni Kala Sangam, last evening. The show was inaugurated by Nishi and SC Sinha IPS (Retd), Member, National Human Rights Commission and the Chief Guests were Shalini and Sanjay Srivastava IAS, Chief Secretary, Govt. of NCT Delhi, and the Guests of Honour was Neha and Balvinder Kumar IAS, Vice Chairman, DDA. Also Read – ‘Playing Jojo was emotionally exhausting’Taking off a day before the International Womens’ Day, this show celebrates the coming of age of womanhood in India as she rises back from the Ashes to claim her rightful place under the sky as the mythical Phoenix Woman. It is a depiction of a real life saga of the inner power and strength of a woman. Compulsively, what the woman holds up inside her is out on the canvas.Renuka Sondhi Gulati paints to exist and sculpts to underline her existence. Her works vivify the journey of a woman from birth to death under going all the pangs of ageing and feeling all the bliss of maturity, and also they capture how a woman becomes a natural multirole person when she exists within the society, family and above all in history. Also Read – Leslie doing new comedy special with NetflixHer paintings are a satire on political and social systems and depict human answers sometimes through struggles and at other times through silent prayers. Unlike the paintings, the sculptures also brings forth male protagonist and at times women and men are seen as couples. Perhaps sculpture medium helps her to play around the idea of love, family, being together and physical and spiritual union.Gulati said that as an artist she does not need to do anything else to be focussed, responsible and rebellious other than doing her works. The works, for her are the junctures of meditation and as she has been working ever since, she is in a constant state of meditation. If anything could be a meditative process, even a rebellion could bring in the same effects. Most of the women meditate with/through their silent rebellions. Out of them, some cut vegetables, some go to office, some fight at borders, some go underground, some just dream; and some women create works of art.Renuka Sondhi Gulati is one who creates art. There are untold stories of Phoenix women all over, here is one from an artist sees no limitations and is finding the way to fly on her canvas.WHEN: On till 16 MarchWHERE: Sridharani gallery, Triveni Kala Sangam
Kolkata: Chief Minister Mamata Banerjee on Thursday announced the payment of Rs 1 lakh each to the three BJP workers who were injured in the collapse of a makeshift tent at Prime Minister Narendra Modi’s rally and are receiving treatment at Midnapore Medical College and Hospital.The money will be paid from the Chief Minister’s Relief Fund. Banerjee, on her way to the convocation of IIT Kharagpur which is scheduled to be held on Friday, paid a surprise visit to the hospital where the three Also Read – Rain batters Kolkata, cripples normal lifeseriously injured have been admitted. “Those who are injured at the Prime Minister’s rally are from lower-middle class families. The doctors have taken proper care and I announce the payment of Rs 1 lakh each to the three injured persons who are undergoing treatment,” Banerjee told reporters here. She had prayed for the quick recovery of the injured persons in a tweet. She also spoke to the doctors and asked them to treat the injured persons with top priority. As many as 90 people were injured, five of them seriously, in the incident. All the injured persons were treated and discharged except these three. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedBanerjee went to the ward where the injured patients have been put up and spoke to them and their family members. She also had a word with the doctors and inquired about their health. She was accompanied by Surajit Kar Purkayastha, the state Security Advisor. It may be mentioned that the state government is conducting an investigation into the collapse of the tent. Senior police officers have spoken to the decorator’s firm that had put up the pandal. A team from the Home ministry had also visited the site and has spoken to senior police officers as well. State Forensic experts have visited the site and collected samples. No report on the cause of the collapse of the pandal has yet been submitted to the state government.
Go beyond just using peanut butter on a toast, and get innovative with it for healthier options, say experts. With increasing awareness about super foods and their health benefits, peanut butter has now made its way to most of the Indian households. It is rich in proteins, energy, carbohydrates and good fat. Nutritionist and weight management consultant Kavita Devgan said, “Peanut Butter is the most innovative ingredient to complement the benefits of peanut in our daily diet. For vegetarians, it can be added to pulses, baby spinach roasted peanut bowl, basil peanuts pesto or sesame peanut chikki. Peanut Butter also goes well with pork and prawn recipes and even pairs very well with tofu.”* Peanut Butter Museli Bar: Eat healthy and tasty muesli bars while on the go. To make delicious bars add muesli, sesame seeds, coconut, cinnamon powder and nuts in a pan and dry roast all. In another pan cook peanut butter, honey and dates for one minute. Pour the peanut butter mixture in the bowl with the dry ingredients and fold the ingredients together, freeze and serve.* Bengal PB Chop: Grace your snack time with easy to make peanut butter chops. Make round balls from a mixture of cooked green chili, ginger, beetroot, potato, carrot, red chili powder, cumin powder, coriander powder. Stuff them with a mixture of peanut butter, raisins and nuts. Then make cutlets and deep fry with coating of suji and breadcrumb.* Peanut Butter Chicken Skewers: Give a delicious twist to chicken with peanut butter. Prepare a mixture of yoghurt, peanut butter, coriander leaves, garlic, salt and red chilli for marination. Place chicken alternatively in skewers and refrigerate for 30 minutes. Heat oil in a non-stick pan (medium flame) and grill skewers for three to four minutes from both sides or until cooked.* Thai Style Peanut and Vegetable Curry: In a blender jar, add garlic, onion, red chilli, turmeric powder, cumin powder and 50 ml water and grind it to form a thick paste, cook the paste for three to four minutes till dry. Add coconut milk, peanut butter, coriander, remaining water, salt and cook for 2-3 minutes until the sauce thickens. Then add lemon juice, broccoli, mushroom, carrot and pineapple. Serve hot with boiled rice.* PB Smoothies: Smoothies are a perfect filling snack and quick on-the-go choice for both adults and children. Choose your favourite base – be it strawberry, banana or chocolate dessert topping. Add peanut butter, yoghurt, milk, honey, ice-cubes and blend it until smooth in a blender jar. Pour in a glass and serve chilled.
The National Gallery of Modern Art, New Delhi, Ministry of Culture, Government of India is organising an exhibition entitled ‘Gurudev: The journey of the maestro’. The event is being organized to commemorate the birth anniversary of Rabindranath Tagore – which falls on May 7. Rabindranath Tagore was fascinated by the worlds of literature, art, music, and dance at an early age. His expression in visual vocabulary is an enormous contribution towards the shaping of the modern art in India and setting a flow for the powerful expressive visual language in context to Indian art. His early paintings included doodles, rhythmical and lyrical lines as well as curves on his manuscripts to scribe out the unnecessary lines or words. These beautiful patterns went on to become his trademark in the art world. Also Read – Add new books to your shelfEach of his visual expression is very individualistic in nature. But for an outline, to enter in his visual world mainly consisting of paintings, one can see them broadly in two major categories. One of which is that of his observations and dialogues with nature and the other being the human – the portrait heads and the figures – which drift in nature or are emerging out of a space.Speaking about the exhibition Adwaita Garanyak, Director General, NGMA said, “I am elated that NGMA is presenting this exhibition at Jaipur House. These artworks of versatile genius give a glimpse of Tagore’s precious contributions to the visual language. I wish to thank Ministry of Culture, Government of India for supporting our endeavors and acknowledge the sincere efforts of the entire NGMA team towards the successful execution of this project.”The exhibition is on view for the public May 8 onwards from 11 am – 6.30 pm, except Mondays and national holidays.