Month: August 2019

Team says Arctic ice shelf broke up before

first_imgImage: NASA/Goddard Space Flight Center Citation: Team says Arctic ice shelf broke up before (2011, October 25) retrieved 18 August 2019 from https://phys.org/news/2011-10-team-arctic-ice-shelf-broke.html Now however, new research by a team from Université Laval in Canada, led by Dermot Antoniadesa, have found, after studying sedimentary material on the bottom of the Disraeli Fiord, created by backup from an ice shelf in Northern Canada, that it experienced a major fracture that resulted in an overall reduction of the ice shelf some 1,400 years ago. Which means this isn’t the first time that the shelf ice has melted and broken apart. The team has published the results of its survey in the Proceedings of the National Academy of Sciences.Shelf ice is a thick platform of ice that has been pushed out to sea by glacier pressure. As the sea level drops, the ice tends to float even as it’s still connected to the shore. Hence its name, it literally looks like a giant shelf hanging off the land out into the sea. One ice shelf in particular, Ward Hunt, located on Ellesmere Island, lies off the north central coast of Canada and is part of a group of ice shelves that once comprised most of the northwest coast of the Island. Over the past hundred years, the shelf ice in this region has diminished by nearly 90%.Because ice shelves also act as dams, backing up water into fjords, sediments from them build up on the sea floor and in the spaces between the salty seawater and fresh water produced by melting ice. By analyzing these sediments using carbon 14 dating and other techniques, the researchers are able to create a record or timeline of sorts that they can use to look into the past. In this case, the research team found that the ice shelf first appeared approximately 4,000 years ago and hung around for several thousand years. But then about 1,400 years ago, a major fracturing occurred that caused the shelf to shrink. It didn’t fully recover until about 800 years ago. After that, it held steady till the shrinkage that began nearly a hundred years ago and continues to this day.At this point, it doesn’t appear that the shelf ice around Ellesmere Island is any smaller now than it was during the previous period of warming, but because it’s still shrinking, it’s possible it could become, as Antoniadesa writes, an “unprecedented” event. © 2011 PhysOrg.com More information: Holocene dynamics of the Arctic’s largest ice shelf, PNAS, Published online before print October 24, 2011, doi:10.1073/pnas.1106378108AbstractIce shelves in the Arctic lost more than 90% of their total surface area during the 20th century and are continuing to disintegrate rapidly. The significance of these changes, however, is obscured by the poorly constrained ontogeny of Arctic ice shelves. Here we use the sedimentary record behind the largest remaining ice shelf in the Arctic, the Ward Hunt Ice Shelf (Ellesmere Island, Canada), to establish a long-term context in which to evaluate recent ice-shelf deterioration. Multiproxy analysis of sediment cores revealed pronounced biological and geochemical changes in Disraeli Fiord in response to the formation of the Ward Hunt Ice Shelf and its fluctuations through time. Our results show that the ice shelf was absent during the early Holocene and formed 4,000 years ago in response to climate cooling. Paleoecological data then indicate that the Ward Hunt Ice Shelf remained stable for almost three millennia before a major fracturing event that occurred ∼1,400 years ago. After reformation ∼800 years ago, freshwater was a constant feature of Disraeli Fiord until the catastrophic drainage of its epishelf lake in the early 21st century. ‘Webcam’ from Space: Envisat observing Wilkins Ice Shelf (PhysOrg.com) — Arctic shelf ice has been in the news of late due to its shrinkage over the past few decades that most attribute to global warning. Thus, its levels and seemingly constant calving have become ecological barometers that environmentalists have come to use to show just how fast our planet is heating up. 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

Voicestress software is put to the test

first_img Explore further (Phys.org) — Computer scientists working in a range of departments, from pervasive computing to mobile computing to sensors, will converge in Pittsburgh for the 14th International Conference on Ubiquitous Computing (Ubicomp 2012) on September 5 through 8. They will learn more there about a team’s software that can recognize stress from vocal patterns. The researchers wanted to see if they could successfully train a system to pick up stress through a person’s voice. Their paper, “StressSense: Detecting Stress in Unconstrained Acoustic Environments using Smartphones,” authored by Hong Lu, Mashfiqui Rabbi, Gokul T. Chittaranjan, Denise Frauendorfer, Marianne Schmid Mast, Andrew T. Campbell, Daniel Gatica-Perez, and Tanzeem Choudhury, details their success. Stress changes how people make decisions: study © 2012 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. (a) the setup of the interview room. (b) the setup of data collection. Image from “StressSense: Detecting Stress in Unconstrained Acoustic Environments using Smartphones”, Hong Lu et al. Citation: Voice-stress software is put to the test (2012, August 22) retrieved 18 August 2019 from https://phys.org/news/2012-08-voice-stress-software.html “We propose StressSense for unobtrusively recognizing stress from human voice using smartphones,” say the authors, and they believe they can demonstrate that their StressSense classifier “can robustly identify stress across multiple individuals in diverse acoustic environments.”Their system is trained first to recognize someone’s unstressed voice. StressSense compares this recording to its preprogrammed knowledge of stress-caused physiological changes, such as faster speech and clipped frequency spectrum. The study authors, including Hong Lu of Intel in Santa Clara, California, found the prototype’s stress-recognition accuracy to be 81 per cent indoors and 76 per cent outdoors.Baseline voice rates for a group of people were gathered. According to their system, the person is told first to relax and read a three-minute passage from a book into the phone. Participants were subsequently placed in stressful job interviews to test the system. The study group totaled 14. Thirteen participants were undergraduate students in fields such as geology, psychology, biology, and law. One participant was a PhD student. Audio data was collected using Nexus One phones at 8kHz 16 bit PCM using a custom Android program that runs in the background, according to the paper.The researchers next plan to design, deploy, and evaluate a StressSense Android app. The inevitable question is what good will it do to be told by one’s own smartphone to chill out. The team is confident that the app carries real and practical benefits. Lu said the software has the potential to raise user awareness of stressful events and to help cope. The interest in voice analysis to recognize stress is not new. The study authors point to pioneering work in 1968 when amplitude, fundamental frequency, and spectrograms were analyzed for speech under task-induced stress . They also noted a body of research on stress detection from speech centered around the Speech Under Simulated and Actual Stress (SUSAS) dataset.“Evidence from experiments with SUSAS suggests that pitch plays a prominent role in stress. Other important features are those using energy, spectral characteristics of the glottal pulse, and phonetic variations (speaking rate) and spectral slope.”As for their own study findings, the team pointed out four contributions of their paper. They experimentally show that 1) stress from human voice can be detected using smartphones in indoor and outdoor conversational data; that 2) a universal stress model can be adapted to specific individual users; 3) a stress model can be adapted to unseen environments, lowering the cost of training stress models for different scenarios; and 4) the proposed stress classification pipeline can run in real-time on off-the-shelf Android smartphones. More information: publications.idiap.ch/download … /Lu_UBICOMP_2012.pdflast_img read more

Physicists design zerofriction quantum engine

first_img Journal information: Scientific Reports (Phys.org) —In real physical processes, some energy is always lost any time work is produced. The lost energy almost always occurs due to friction, especially in processes that involve mechanical motion. But in a new study, physicists have designed an engine that operates with zero friction while still generating power by taking advantage of some quantum shortcuts. Quantum engines must break down Explore further Scientists have devised a way to run a quantum cycle based on the use of quantum shortcuts to adiabaticity, where friction-like effects are quenched. Shown are the four steps of a quantum Otto cycle, where heat enters (exits) the working medium and those where work is performed by (done onto). Credit: A. del Campo, et al. ©2014 Nature Scientific Reports 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 The laws of thermodynamics successfully describe the concepts of work and heat in a wide variety of systems, ranging from refrigerators to black holes, as long as the systems are macroscopic. But for quantum technologies on the micro- and nano-scale, quantum fluctuations that are insignificant on large scales start to become prominent. As previous research as shown, the large quantum effects call for a complete reformulation of the thermodynamics laws.What a quantum version of thermodynamics might look like is not yet known, and neither are the limitations or possible advantages of the quantum devices that would be described by such laws. However, one intriguing question is whether it may be possible to build a reversible quantum engine—one in which the engine’s operation can be reversed without energy dissipation (an “adiabatic” process).In the new paper, the physicists have shown one example of a quantum engine that is “super-adiabatic.” That is, the engine uses quantum shortcuts to achieve a state that is usually achieved only by slow adiabatic processes. This engine can achieve a state that is fully frictionless; in other words, the engine reaches its maximum efficiency, while still generating some power.”Shortcuts allow us to ‘mimic’ what would be achieved by running a cycle quasi-statically, i.e., very slowly, while performing transformations at finite time,” coauthor Mauro Paternostro at Queen’s University in Belfast, UK, told Phys.org. “Now, consider for instance a compression or expansion stage of a cycle run using a piston. When doing it at finite time, i.e., non-zero velocity, friction might affect the performance of the transformation. Yet, by using a shortcut to adiabaticity, friction-like effects would get quenched, the cycle performance being the same as that of a quasistatic motor.”The work marks a step toward the key engineering goal in this context, which is to find the maximum efficiency allowed at the maximum possible power. As the scientists note, this pursuit is complicated by the existence of a trade-off between the running time of the super-adiabatic process and the corresponding amount of work dissipated.”This work is one of the first steps into the merging of quantum control and thermodynamics,” Paternostro said. “We have shown that it is possible to use techniques that, to date, have only been used for other goals (population transfer, for instance) for thermodynamic tasks and the engineering of efficient cycles.”Overall, the results suggest the possibility of a frictionless quantum engine operating at maximum efficiency, which has implications in designing micro- and nano-scale motors operating at the verge of the quantum scale. In the meantime, there are still several hurdles to overcome.”I think that the real challenge is the use of such techniques in interacting quantum many body systems, whose inherent complexity and rich phenomenology could be ‘tamed’ by the use of this sort of quantum control,” Paternostro said. “At the end of the day, thermodynamics is a theory of many particles, and its quantum formulation should be able to cope with many-body effects, whose control could hugely benefit from the implementation of schemes similar to the one proposed in our paper. We have new and exciting results, in this context, that will come up soon and that will hopefully have an impact in the community interested in many-body physics and quantum thermodynamics.” Citation: Physicists design zero-friction quantum engine (2014, September 16) retrieved 18 August 2019 from https://phys.org/news/2014-09-physicists-zero-friction-quantum.html More information: A. del Campo, et al. “More bang for your buck: Super-adiabatic quantum engines.” Scientific Reports. DOI: 10.1038/srep06208 © 2014 Phys.orglast_img read more

Best of who you can be

first_imgEk Nayi Pehchaan, a personality development programme, designed for women, is being organised in the Capital at Le Meridian on 21 September by AIS. The show will be inaugurated by Sharon Lowen, while the guest of honour will be Renu Shahnawaz Hussain.  Actress Surveen Chawla will grace the occasion with her presence.  The panel of speakers at the programme includes – Rina Dhaka (fashion designer), Laxmi Aggarwal (acid attack fighter), Sanjana Jon (fashion designer), Sminu Jindal (MD of Jindal SAW ltd.), Anjana Kuthiala (artist), Alka Raghuvanshi (art curator and artist), Ramon Lamba (Life Coach) and Alexshendra Venus Bakshi (writer). Also Read – ‘Playing Jojo was emotionally exhausting’Dhaka will be speaking on ‘power dressing’ a much talked about concept between women of all ages. Laxmi will speak on self-confidence as a tool to overcome all the odds and difficulties of life. At the same time, she will share some extremely motivating and realistic approach to self-confidence and how she overcame the most difficult phase in her life with a firm belief in her own ability, skills and experiences. Jon will throw light on ‘Celebrating Girl Child’ and have an interaction with people as how today, girls face discrimination in many parts of the world simply because of their gender. She aims to create awareness towards improving girl child sex ratio in our country and to ensure that every girl child is given a chance to outshine, by providing her proper education accompanied with basic necessities for her proper growth and development. Also Read – Leslie doing new comedy special with NetflixThese interactive sessions will not only bring out some rather untouched topics out but with that provide everyone with a way to overcome it and adapt with the changes. The event is a part of the initiative movement on ‘Indian Women Empowerment’ led by AIS. The initiative involves organising and conducting various multi-facet personality development workshops, specifically designed for women in India with sole aim to motivate and empower women. The first part of the movement was the workshop Liberalize with English held in the Capital. When: 21 September Where: Le Meridian, Connaught Place Timing: 1 – 4 pmlast_img read more

Shafqat mesmerises IITians

first_imgIIT Delhi in collaboration with IIT Delhi Alumni Association witnessed its Alumni Day with an inordinate success on December 28. The iconic event was honoured with the theme, Envision the Future Together, to strengthen the Alumni – Alma Mater bond and to explore ways to give back to the institute. Not only IIT Delhi but all IIT chapters across the world on the same day in accord with the main event memorialized the Alumni Day Event. The alumni day zealed with the riveting performance of the famous Pakistani singer Shafqat Amanat Ali and made the audience to dance on his magnificent performace.   Also Read – ‘Playing Jojo was emotionally exhausting’The IIT Delhi Dogra Hall was jam packed with his fans who danced to the tunes of his evergreen songs, Dildara, Phir Le Aya Dil, Mora Piya Mose, Mitwa and many more. The presence  of the classical singer filled the ambiance with a spirit of liveliness and positivity and it gave a vivacious closing to the Alumni day.  The Pakistani classical singer  expressed his pleasure of being at IIT Delhi Alumni Day and performing in front of such enthusiastic crowd. He came along with his masterly band who utterly made the evening breathtaking.  Alumni Day ensured the mix of fun, fundas, food and friends and made it a day to cherish for alumni and their families. Also Read – Leslie doing new comedy special with NetflixAddressing the guests IIT Delhi Alumni Association’s President, Ashok Kumar says, “We aimed to ingrain the Entrepreneurial DNA in our students/ faculty . The sessions focused on empowering industry partnerships on specific technology areas and how Alumni can collaborate with IIT Delhi to make meaningful innovations to create a feeling full impact on the society. We indebt our gratitude to Shafqat Amanat Ali for creating such a mellifluous environment and took all of us in his soothing musical path.”last_img read more

JU authorities urge students to end hunger strike

first_imgKolkata: Two of the 20 members of a students’ union of Jadavpur University who are on a hunger strike, over the past four days, in protest against the new admission procedure, have been hospitalised today, varsity authorities said. The authorities made a fresh appeal to them to withdraw the stir and called an emergency executive council meeting today. Registrar Chiranjib Bhattacharya said two students have been admitted to hospital and the varsity was concerned about the health condition of others. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killed Accompanying the Registrar, Pro-VC Pradip Ghosh told the students, “I request all of you to withdraw the fast. We have already convened an emergency executive council meet to discuss the admission issue. The VC (Suranjan Das) and Chancellor (Keshari Nath Tripathi) have already requested you to withdraw the fast. Please do not endanger your lives.” Turning down their pleas, general secretary of Arts Faculty Students’ Union Debraj Debnath said, “There is no question of withdrawing our fast till the EC scraps the marks only criteria for admission process and brings back the admission process.” Also Read – Naihati: 10 councillors return to TMC from BJP Governor Keshari Nath Tripathi, who is also Chancellor of the university, had yesterday expressed concern over the health of the students. Vice Chancellor Suranjan Das had also urged the agitating students to call off their hunger strike. Debraj claimed that three students, including the assistant general secretary of the Arts Faculty Students’Union (AFSU) Ushashi, had to be hospitalised today but their condition was now stable. The AFSU said four students, including AFSU chairperson Somashree, had to be admitted to hospital. Around 20 members of the AFSU started a hunger strike on July 6, two days after the university announced that it would admit undergraduate students in English, comparative literature, Bengali, history, political science and philosophy on the basis of board marks, reversing its earlier decision to hold entrance tests The All Bengal University Teachers’ Association, JU chapter, in a letter urged the VC to end the impasse by taking the opinion of all the stakeholders and called for upholding the functional atutonomy of the institution. The governor, in a letter to the university, had also said that while the EC usually takes decisions on different issues faced by the university, the VC was empowered to take certain decision on his own, in case of exigencies. Jadavpur University has been embroiled in controversies since July 4, when the executive council announced its decision to scrap entrance tests for the six subjects. An hour after the announcement, the students had gheraoed the VC and other members of the executive council to protest the move. The gherao, which lasted for 30 hours, was followed by JUTA ceasework, class boycott and indefinite fast by AFSU members.last_img read more