Nevertheless, these cloud seeding techniques are controversial, both for their effectiveness at inducing rainfall and for their possible harmful side effects. In a recent review paper published in the IOP’s Journal of Physics D: Applied Physics, a team of scientists from Switzerland and Germany has examined the latest results of laser-induced condensation and discussed the future of the field.One of the first successful demonstrations of laser-induced condensation (http://www.nature.com/ncomms/journal/v2/n8/full/ncomms1462.html) came just last year, when researchers – including the authors of the current review – used a powerful laser to produce tiny water particles in moderately humid air. The water particles were just a few micrometers in diameter, which is about 100 times too small to fall as rain droplets. However, the experiments demonstrated the ability to transform particles in a gas phase to a liquid phase through condensation, and larger droplets are expected to be feasible.“At this stage, our work clearly shows that lasers can induce the formation of tiny particles,” Jérôme Kasparian of the University of Geneva in Switzerland told Phys.org. “This is not, at least at this stage, efficient cloud seeding for making rain, but rather a newly opened direction for research in this direction.” (Phys.org) — Although pointing high-energy lasers at the sky to cause pouring rain is currently a high-tech dream, the motivation behind controlling the weather has existed since the days of our ancient ancestors. Throughout human history, many civilizations developed magical or religious methods in an attempt to increase or decrease precipitation. In light of this history, current techniques that shoot laser beams or launch chemicals into the sky for the same purpose seem to be just the latest manifestation of this goal. Lasers could be used to make rain (w/ Video) Laser-induced condensation in a cloud chamber, illuminated by a green auxiliary laser. The cloud’s deformation reveals the air turbulence due to energy deposited by laser filaments. Image credit: J. Kasparian, et al. ©2012 IOP Publishing Ltd As the researchers explain in this review, laser-induced condensation owes its feasibility in part to the rapid improvement in laser power in recent years. Over the past decade, commercially available laser power has increased by two orders of magnitude, reaching the petawatt level today. Scientists expect laser powers on the exawatt scale in the foreseeable future. In last year’s demonstration, the researchers performed experiments using a 100-TW Draco laser and 5-TW mobile laser called Teramobile, which is the size of a 20-foot freight container. In addition to more powerful lasers, improving the results will also require a better understanding of the underlying mechanism of laser-induced condensation. The technique involves photodissociation, in which photons break down atmospheric compounds in the atmosphere. This process produces ozone and nitrogen oxides, which lead to the formation of nitric acid particles that bind water molecules together to create water droplets. Understanding the details of how this process stimulates particle growth, as well as how atmospheric conditions affect the process, are the most challenging questions in this field, according to the scientists.“Making rain would require first to have tiny water particles grow into droplets with a size sufficient to fall as raindrops,” Kasparian said. “This depends on the atmospheric conditions, in particular the relative humidity, that these particles will encounter. For example, if the air mass in which the particles have been produced lifts along a mountain hill, it will cool down and condensation will be favored.“Making rain would also require the production of an adequate number density of particles. If there are too few particles, we would only get a few drops at most. On the other hand, if there are too many particles, they will compete with each other to grab the water molecules available in the atmosphere. Ultimately, none of them will grow sufficiently to make raindrops, which may even reduce precipitation.“Finally, the technique would also need to activate a large volume of the atmosphere, i.e., to sweep the laser sufficiently fast.”Despite these challenges, the scientists also noted that using lasers to induce rain has its advantages, particularly its minimal side effects compared to other techniques. For example, cloud seeding methods that involve injecting silver iodide particles into clouds run the risk of having unintended consequences for the surrounding atmosphere, a problem that lasers avoid. Laser-assisted methods also offer better control than chemical methods, since the lasers can be turned on and off and precisely positioned. This control also makes it easier to determine how effective the technique is, since critics often question whether rain might have occurred even without intervention.In the future, the researchers recommend investigating the ability of lasers to seed clouds on a larger scale. Such a task will require further experimental data as well as theoretical modeling.“Our aim now is to tackle the questions that remain open, especially to determine the optimal laser conditions to maximize the condensation process, and to assess for the possibility to obtain macroscopic quantities of condensed water,” Kasparian said. “This also requires an understanding of the physical mechanisms at the root of laser-induced condensation, with the ultimate goal of being able to model the process quantitatively.“Besides the technical feasibility, as discussed above, further experiments will allow us to assess whether laser rainmaking could be cost-effective. This can easily be expressed in terms of the cost per unit rainwater volume obtained. This will depend very much on the ultimate laser power required to get a significant amount of water, which we need to further investigate.” Copyright 2012 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 PhysOrg.com. A high-powered laser pulse 10-cm in diameter generates multiple filaments, which is necessary for laser-induced condensation. Laser filaments can be generated at kilometer-range distances. Image credit: J. Kasparian, et al. ©2012 IOP Publishing Ltd Journal information: Journal of Physics D: Applied Physics Explore further Citation: Scientists analyze potential of using lasers to make rain (2012, July 16) retrieved 18 August 2019 from https://phys.org/news/2012-07-scientists-potential-lasers.html More information: J. Kasparian, et al. “Laser-assisted water condensation in the atmosphere: a step towards modulating precipitation?” J. Phys. D: Appl. Phys. 45 (2012) 293001 (13pp). DOI:10.1088/0022-3727/45/29/293001 http://iopscience.iop.org/0022-3727/45/29/293001 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.
Journal information: Proceedings of the Royal Society B New fossils suggest ancient origins of modern-day deep-sea animals For most of modern science, ocean scientists have believed that the open ocean is a near desert, with few living creatures in it. Because of that, the consensus has been that most of the animals that do live in the deep sea today, likely evolved in shallow waters and then migrated there over millions of years. In this new effort, the researchers report on an excavation in the Austrian Alps that has yielded many fossils from ancient deep sea animals.The team has thus far found over 2,500 fossils which have been identified as deep sea animal remains because they were clearly sea dwellers that were not light dependant. Also the rock in which they were found was similar to rock on ocean seafloors. Closer analysis of the fossils dates them back approximately 180 million years. Prior discoveries of ancient sea creature remains had been found in shallow waters, which was another reason scientists have believed deep sea creatures evolved from shallow water creatures. But the new fossil find predates any other existing find by 25 million years, suggesting they evolved from a deep sea ancestor. In comparing the deep sea fossils with fossils from shallow living creatures from the same time frame, the researchers made another discovery. The deep sea appeared to have more biodiversity millions of years ago, than more shallow waters, turning conventional thinking on its head. (Phys.org) —A team of researchers with members from several European countries has published a paper in the journal Proceedings of the Royal Society B: Biological Sciences, arguing that new archeological evidence suggests not all deep sea creatures evolved in shallow waters and then moved deeper. Fossil discoveries in the Austrian Alps, they claim, offer evidence that some deep sea creatures actually evolved in the deep sea and are the ancestors of many modern deep sea creatures. Explore further Credit: © Ben Thuy The findings by the team add more credence to the more recent view that areas of the deep sea actually have some of the highest levels of biodiversity on the planet. But, they caution, such conclusions should not imply that the deep sea may be better able to withstand changes wrought by us humans, because no one really knows if that is true or not. Credit: © Ben Thuy More information: First glimpse into Lower Jurassic deep-sea biodiversity: in situ diversification and resilience against extinction, Published 21 May 2014 DOI: 10.1098/rspb.2013.2624 © 2014 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. Citation: Fossil discovery in Alps challenges theory that all deep sea animals evolved from shallow water ancestors (2014, May 21) retrieved 18 August 2019 from https://phys.org/news/2014-05-fossil-discovery-alps-theory-deep.html Credit: © Ben Thuy
(Phys.org)—Quantum measurements are often inherently unpredictable, yet the usual way in which quantum theory accounts for unpredictability has long been viewed as somewhat unsatisfactory. In a new study, University of Oxford physicist Chiara Marletto has developed an alternative way to account for the unpredictability observed in quantum measurements by using the recently proposed theory of superinformation—a theory that is inherently non-probabilistic. The new perspective may lead to new possibilities in the search for a successor to quantum theory. Citation: A non-probabilistic quantum theory produces unpredictable results (2016, September 21) retrieved 18 August 2019 from https://phys.org/news/2016-09-non-probabilistic-quantum-theory-unpredictable-results.html Physicists retrieve ‘lost’ information from quantum measurements “The decision-theoretic approach shows that a rational agent that knows unitary quantum theory only (but does not assume the Born rule) would have the same expectations, in the experimental situations where the Born rule applies, as if he had assumed the Born rule,” Marletto explained. “This is a remarkable result, but has been contested on the grounds that it relies on axioms of rationality that seem subjective and not physically motivated.” Deterministic quantum theoryIn the new paper, Marletto builds on the decision-theoretic approach to show that a completely deterministic quantum theory can essentially function as if it were probabilistic, so that measurements would be expected to produce unpredictable results, like those in the double-slit experiment and many others.”There are two things: one, my work shows that unpredictability can arise under deterministic theories, and that it is a direct consequence of the impossibility of cloning certain sets of states,” Marletto told Phys.org. “That unpredictability can arise under deterministic theories may seem a little surprising at first. But the point is that ‘unpredictability’ just means that it is impossible to build a predictor—a machine that would reliably predict the outcome of a single measurement of given observable on a system prepared in a given state. This impossibility is just like that of the no-cloning theorem, and does not require any probabilistic structure. Probabilities, instead, come into play only when considering patterns occurring in repeated experiments.”Two, this work updates and generalizes the decision-theory approach to the Born rule in quantum theory, which was proposed to reconcile deterministic unitary quantum theory without the Born rule with the appearance of stochasticity in quantum experiments. In particular, it shows that most of the assumptions of that approach are not, as previously thought, subjective decision-theoretic axioms, but follow from physical properties of superinformation theories. It also establishes under what conditions superinformation theories support that argument, thereby defining a class of theoretical possibilities in which the successor of quantum theory might be sought.”Overall, the new results show that, to explain quantum experiments that have perplexed physicists for decades—experiments in which repeated, identical measurements produce different outcomes, where individual outcomes are unpredictable and appear to be random–it is not necessary to appeal to the Born rule or any other probabilistic assumptions. Possibilities and impossibilitiesAs Marletto explains in her paper, her work builds on recent research in which she and Deutsch, also at Oxford, reformulated quantum theory as a type of superinformation theory under a new framework that they call the constructor theory of information. When Deutsch and Marletto originally proposed the constructor theory of information a couple of years ago, they were searching for a way to link classical and quantum information under the same general framework. In the end, what they developed was a set of principles that can be thought of as part of the foundations from which all the laws of physics emerge—essentially, a new fundamental theory of physics.The basic principle of constructor theory is that every law of physics must be expressible as a statement about which physical transformations (or tasks) are possible and which are impossible, and why. An example of a possible information processing task under quantum theory is switching any state to any other state, and vice versa. An example of an impossible task is cloning, which is creating an identical copy of an unknown state. Constructor theory does not specify any particular laws of physics, but instead its principles are intended to supplement and underlie all laws of physics, both the known and currently unknown laws. This is similar to the way in which fundamental principles, such as conservation of energy and mass, must be obeyed by all laws of physics. Specific laws can be formulated to predict what will actually happen (not just what is possible) in specific circumstances. For example, some laws predict the trajectory of a projectile, others predict the flow of water, or the path of electricity, etc., always with the constraint of complying to constructor theory’s principles. These restraints also provide a potential way to test the theory.”The main way to test constructor theory is to test the theories conforming to its principles—for instance, the interoperability principle for information,” Marletto said. “So, the same as one would do to test the principle of conservation of energy. In regard to the class of superinformation theories, they might be used to design new experiments about quantum theory, by providing a space of new theoretical possibilities where a rival of quantum theory may be sought. The promising feature is that, unlike most existing proposals for frameworks to generalize quantum theory, superinformation theories are deterministic and local.”In the future, Marletto plans to work on further developing the constructor theory framework, along with the superinformation theories it supports.”Superinformation theories allow one to unify classical and quantum information under the same framework,” she said. “There are exciting prospects about understanding what other superinformation theories there are in addition to quantum theory; coming up with measures of entanglement or quantum coherence in this generalized scenario would have the advantage of being more general than current quantum-information-theoretic ones. Another line of research that appears very interesting is to merge the theory of superinformation with the newly proposed constructor theory of thermodynamics, which will have bearings on the current quantum thermodynamics enterprise. There is also a project that Deutsch and I would like to pursue, that is to understand how superinformation theories can support the notion of ‘relative state,’ which is crucial in unitary quantum theory.” Explore further Accounting for unpredictabilityThe unpredictability observed in quantum experiments is one of the unique features of the quantum world that sets it apart from classical physics. One prominent example of quantum unpredictability is the double-slit experiment: When sending a stream of particles (such as photons or electrons) through two small slits in a plate, the individual particles are detected at different locations on a screen behind the plate. Although it’s possible to predict the probability of a particle impacting at a certain location, it’s not possible to predict specifically where any individual particle will end up.Traditionally, this apparent probabilistic behavior that is observed in experiments has been accounted for in quantum theory by using the Born rule. In 1926, the German physicist Max Born developed this rule to determine the probability of finding a quantum object at a certain location—or more generally, the probability that any measurement on a quantum system will produce a particular observed outcome, depending on the quantum state of the object. The Born rule is a unique part of quantum theory in that it is the only stochastic, or randomly determined, element in quantum theory. The Born rule has basically been added by fiat on top of a theory that is otherwise deterministic. Ever since the rule was first proposed, physicists have questioned the probabilistic nature of quantum theory with the Born rule, and have wondered whether it would still be possible to account for observations, including unpredictability, without this rule. In general, quantum theory without the Born rule would be completely non-probabilistic. The main problem with the proposal for such a theory, called “unitary quantum theory,” is that it does not appear, at first sight, to agree with the observations of unpredictability in quantum measurements. One attempt to reconcile this conflict is the so-called “decision-theoretic approach,” which was recently proposed by David Deutsch and established by David Wallace, and which forms the basis for the arguments in the new study. © 2016 Phys.org Journal information: Proceedings of the Royal Society A More information: Chiara Marletto. “Constructor theory of probability.” Proceedings of The Royal Society A. DOI: 10.1098/rspa.2015.0883. Also at arXiv:1507.03287 [quant-ph] 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 scheme in superinformation theory. The new study shows that this deterministic theory exhibits unpredictability as a consequence of the impossibility of cloning certain states. Credit: C. Marletto. ©2016 Proceedings of The Royal Society A
Kolkata: Senior officials of the Customs along with the police seized gold biscuits worth nearly Rs 66 lakh from a house at Jorabagan area on Monday night. Acting on a tip-off, the Customs officials conducted raids and arrested two persons for their alleged involvement in a gold smuggling racket. They have been identified as Tushar Kadam and Sanjay Chouhan.According to the preliminary investigation, the police and Customs officials suspect that the accused might be a part of an international gold smuggling racket. There are some other persons involved in it too. Also Read – Heavy rain hits traffic, flightsDuring interrogation, the police came to know that the accused changed their route following some recent incidents in which smugglers who brought gold bars and biscuits from abroad were intercepted at the Calcutta airport. The duo started smuggling gold along the India-Bangladesh border in certain districts. They also used to sell gold in various parts of the country which were brought from Dubai.It may be mentioned that there were multiple attempts to bring gold to the city from Dubai as the price of the yellow metal is higher in India. As there was stringent surveillance in all the airports, it has become difficult for the smugglers to bring in gold from abroad. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedPolice have seized around 19 gold biscuits weighing around 2.85 kg for which the market value is around Rs 66 lakh. Customs officials and cops were trying to know if some other persons are involved in the racket. The Customs officials suspect that it might have connection with other gold smuggling rackets operating from the country. Raids are being conducted. Involvement of Bangladeshi nationals in this incident is not being ruled out.
Kolkata: The West Bengal Medical Council (WBMC) on Friday questioned three doctors involved in the death of Kuheli Chakraborty – a 4-month-old child who died of alleged medical negligence after colonoscopy at a city hospital.”This was the third hearing at the Council. The enquiry that has been conducted so far has found negligence on the part of the Apollo Hospital authorities. The child was given no food for a long time and then, medicine was given to her on an empty stomach. This may have resulted in the death. We will be holding more hearings to arrive at a conclusion,” said WBMC president Nirmal Maji. Also Read – Heavy rain hits traffic, flightsAccording to sources, pediatrician Baishali Roy, Subhas Tiwary, who was on duty at the ITU and Sanjay Mahawar (anesthesiologist), deposed before the council on Friday. Tiwary has admitted that he was not aware of the side effects of the medicine that was given to the child, an official in the council said.Gastroenterologist Mahesh Goenka, who was also scheduled to appear for the hearing, did not turn up. “We will act tough against such negligence and will take steps,” the official reiterated. The deceased child’s parents were present at the time of the hearing. “We will fight till those responsible for the death of my daughter are punished,” said Shalu Chakraborty, Kuheli’s mother. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedIt may be mentioned that 4-month-old Kuheli died at the hospital on April 19, 2017, after a colonoscopy. Her parents Abhijit and Shalu Chakraborty had alleged medical negligence and lodged a complaint with Phoolbagan police and the West Bengal Clinical Establishment Regulatory Commission.The West Bengal Clinical Establishment Regulatory Commission, in its verdict on June 23, 2017, had found prima facie negligence on part of the doctors and had forwarded the case to WBMC.
Kolkata: With more youth and students showing interests in mountaineering and adventure sports in the state, the West Bengal Mountaineering and Adventure Sports Foundation (WBMASF) under the state Youth Services and Sports department has framed a uniform guideline that has to be followed by all the clubs in Bengal to provide training on the same.Sources say the guideline has already been framed following discussions and proposals by the members of the WBMASF. Senior officials of the Youth Services and Sports department are also members of the foundation and they have put forward the suggestions of the state government in this connection. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedA high-level meeting of the foundation will be held on July 6 where aspects related to the newly framed guideline will be discussed. In the same meeting, decisions will be taken on trip itineraries, like which club will take students and youth for training in adventure sports and location among other details.There are around 100 clubs in the state that take students and youth to different locations, which include Joychandi, Mathaguru and Gajaguru areas in Purulia and Susunia hills in Bankura for training in mountaineering, rock-climbing, altitude trekking, hang gliding, jungle safari and river crossing. Also Read – Naihati: 10 councillors return to TMC from BJPThe training takes place between November and February.The Youth Services and Sports department provides necessary assistance to each one of the clubs for taking students and youth for training.The clubs get the assistance after successful completion of the training programme with at least 20 boys and girls in each group including two selected from the area where the training would take place or from economically challenged families.Most of the participants in the training programme are the usually students of class VII to XII. According to an official, the guideline has already been framed. Hence, the next step would be to make all the clubs well aware of it.”In a bid to make the clubs aware of each and every aspects of the newly framed guideline, a work shop will be organised in November beginning,” the official said.The workshop will be for 5 days where one member from each club would be present. “The representatives will be going through both theoretical and practical sessions in the workshop. It will help them to follow the guideline while providing training to youth and students,” the official maintained adding that introduction of a uniform guideline for all clubs will benefit the trainees as it has been framed following all rules and regulations.Moreover, the clubs will also get a clear picture on the focus areas of the training programmes on mountaineering and adventure sports.
Kolkata: The indefinite fast of six students of the state-run Calcutta Medical College and Hospital entered sixth day today. The fast was undertaken to press for their demand for accommodation in a new hostel which is allotted only for first year students, the agitating students said. Principal Uchhal Bhadra, in a fresh appeal, today urged the students to withdraw the fast. “With the admission process to the first year going on, I urge the students not to continue the fast. We will sympathetically consider their problem. We are ready for dialogues any moment. We had previously held talks on July 13. Our doors are open all the time,” he said. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killed The fasting students belonged to the second, third and fourth year of the state-run medical college and hospital. They demanded that senior students should be housed in the newly-built hostel complex which has plenty of spaces and they should not forced to put up at the “run-down, old hostel building for seniors.” Bhadra told reporters today that the old hostel building will be renovated very soon and those senior students, who are facing accommodation problem, can be put up there. Also Read – Naihati: 10 councillors return to TMC from BJP The principal earlier said as per guidelines of the Medical Council of India (MCI), freshers and seniors cannot be accommodated in the same hostel building to prevent incidents of ragging. He said the college authorities were ready to address the problem faced by the agitating students but accommodation at the new hostel building was not possible. The students, however, said, “Our demand is non-negotiable.” Two of the fasting students have fallen ill during the past four days. Apan Samanta and Soumyadip Roy were taken to emergency on July 13 and were currently under treatment, Ayan Dey, a third year student said. In place of the two hospitalised students, two others have joined the fast, Soumyadip Dutta, another third year student said. On July 5, the senior students had gheraoed the principal. However, the gherao was withdrawn after the police were called in.
India’s middle-order mainstay Ajinkya Rahane on Friday promised that the team’s batsmen would put up a much more impressive display against spinners in the coming four-Test series against South Africa than they had in the last few rubbers.Agreeing that Indian batsmen did not do too well against the spinning ball in Sri Lanka, Rahane said things would be different against South Africa at home.“Unfortunately, we got out to spinners in Sri Lanka. We played fast bowling very well in Australia and South Africa. The intention was to play out their first spells and then take them on. We are just looking to improve against spin in the series against South Africa. I’m confident in the series against South Africa we will do well against spin,” he said. Also Read – A league of his own!While rubbishing suggestions that
Kolkata: Abhishek Banerjee, president of Trinamool Youth Congress and the party’s MP, has become the co-chairman of the advisory committee of the Trinamool Chhatra Parishad (TMCP).Partha Chatterjee, party’s secretary general is the chairman of the committee. The other members are Ashok Deb, Tapas Roy and Baisanar Chattopadhyay. Jaya Dutta, former TMCP chairperson, is the convenor of the committee.A high-level meeting was held at Trinamool Bhavan on Saturday afternoon in which the general secretaries and unit presidents of the TMCP were present. It was decided that the members of the former TMCP committee will tender resignation to Baisanar Chattopadhyay within a week so that the new committee may be constituted. It may be mentioned that party supremo Mamata Banerjee had announced the reconstitution of the committee at the rally to celebrate the TMCP Foundation Day on August 28. Also Read – Rain batters Kolkata, cripples normal lifeSubrata Mukherjee, veteran student leader of the 1970s and state Panchayats and Rural Development minister, shared his experiences with the young leaders during an interactive session. Chatterjee said outsiders will not be allowed in the colleges. The party will not tolerate any disturbance by the students and the sole responsibility of the TMCP units will be to assist the students to achieve better academic goals. He said the TMC wants more and more students, particularly girls, to participate in politics so that they can become future leaders.Chatterjee said people from all walks of life will take part in the rally that will be held to protest the spiraling price rise of petrol and diesel on September 10. The rally will start from Moulali at 3 pm and end at Dorina Crossing. He added that those taking part in the rally will march along one side of the road so that buses and vehicles can ply without any inconvenience.