This transmission electron microscope image shows carbon nanotubes (dark areas) within a cell nucleus. Carbon nanotube device channels heat into light The cells analyzed were treated with nanotube solutions over time periods of two and four days at concentrations between zero (no nanotubes) and 10 micrograms (millionths of a gram) per milliliter.The images revealed that even cells subjected to the highest nanotube concentrations were still relatively healthy after two days; there were no major differences between the control cells, which were not treated, and the nanotube-treated cells. But after four days, even the lower concentrations led to a significant decrease in the cells’ viability.After two days, the nanotubes had entered the cells’ lysosomes, organelles in the cytoplasm that cause the breakdown of metabolic substances and foreign particles within the cell. After four days, the nanotubes had fused together; some had entered the cytoplasm and crossed into the nucleus.“Uptake to these sites implies that the nanotubes may interact with intracellular proteins, organelles, and DNA, which would greatly enhance their toxic potential,” said Porter.The two imaging techniques used are transmission electron microscopy (TEM) and confocal microscopy. In TEM, a beam of electrons passes through a thin specimen, forming an image that is recreated on a fluorescent screen, photographic film, or detected by a camera. Confocal microscopy involves the use of light to increase the contrast of an image by eliminating all light that is not in the focal plane of the image, resulting in a much sharper image.Citation: Alexandra E. Porter, Mhairi Gass, Karin Muller, Jeremy N. Skepper, Paul A. Midgley and Mark Well Nature Nanotechnology advance online publication, 28 October 2007 (doi:10.1038/nnano2007.347)Copyright 2007 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 This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of PhysOrg.com. Explore further For the first time, scientists have directly imaged carbon nanotubes entering and migrating within human cells, determining as a result that whether the nanotubes cause cell death depends on the dose and exposure time. The work, published in the October 28 online edition of Nature Nanotechnology, may lead to better ways of determining carbon nanotubes’ toxicity to humans. Citation: First Direct Images of Carbon Nanotubes Entering Cells (2007, November 15) retrieved 18 August 2019 from https://phys.org/news/2007-11-images-carbon-nanotubes-cells.html This study is the first to show definitively that carbon nanotubes have the ability to cross into the cytoplasm and nucleus of a cell. Many studies have explored the toxicity of carbon nanotubes, some concluding that the nanotubes are acutely toxic and some not. But the uptake of carbon nanotubes by cells has never before been directly observed, casting doubt on the accuracy of those studies.“Contradictory data on the toxic effects of single-walled carbon nanotubes highlight the need for alternative ways to study their uptake and cytotoxic effects in cells,” lead scientist Alexandra Porter, of the University of Cambridge in the UK, said to PhysOrg.com. “But the direct observation of cellular uptake of single-walled carbon nanotubes has been hindered by difficulties in discriminating carbon-based nanotubes from carbon-rich cell structures.”Porter and her colleagues from the University of Cambridge and Daresbury Laboratory, also in the UK, used two types of microscopy to image single-walled carbon nanotubes as they entered macrophages, which are cells of the human immune system. They “watched” the nanotubes enter the cytoplasm, certain organelles, and the nuclei.The group chose macrophages because they are the first line of defense against foreign materials in many tissues in the body, including lung tissue. Nanoparticles that are inhaled, such as carbon nanotubes in powder form, should be ingested by macrophages, which may stop the nanotubes from getting further into the body’s system, such as the blood and lymph systems (lymph is a clear fluid containing white blood cells and tissue waste that is part of the body’s defense against infection).The cells were analyzed both stained and unstained and the results compared to two common viability tests, or “assays.” These assays gauge the health of the cells using different markers, and thus can have different results. On the other hand, the imaging techniques the scientists used determine cell death by allowing clearly defined structural changes to be identified, and could therefore become an essential complement to carbon-nanotube toxicity assays. 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) — Jeff Bezos the founder of Amazon.com has embarked on an interesting and unique project that, if all goes well, will last the test of time, a whole lot of time. He is looking to create a clock that is able to run for 10,000 years. $42 million has already been put towards the creation of the clock to date, all of it from Mr. Bezos private fortune. Explore further To Mr. Bezos the clock is not just about creating a timepieces that will give him the ultimate in bragging rights, even among the super rich. It is his hope that by building a clock meant to stand the ages it will alter the way that humans think about time and the way that we act, encouraging future generations to take a longer-term view. More information: www.10000yearclock.net/learnmore.html and longnow.org/clock/ If, at first, this sounds like a bit of a strange project you have to understand why Mr. Bezos wants to make a giant clock that will keep time long after his great-great-grandchildren are dead and gone and Amazon.com is less than a faint memory in the collective of the web. Citation: Amazon.com founder to make 10,000 year clock (2011, June 23) retrieved 18 August 2019 from https://phys.org/news/2011-06-amazoncom-founder-year-clock.html © 2010 PhysOrg.com Clocking in and out of gene expression The clock, which will be built into a mountain ridge, represents a monumental feat of engineering, since it will have to run for as long as it took to create all of human civilization. Keeping a clock operational and accurate over this epic of a time span is no small feat. The clocks accuracy will be maintained by a complex set of calculations made by the Jet Propulsion Laboratories that will calculate the suns position at noon for the next 10 millennium. This will allow the clock to automatically correct its time. 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.
They achieved an overclocked frequency of 8.429 GHz on the processors, breaking their former record of 8.308 GHz.Overclocking refers to the process where technical experts get chips to run at higher than normal speeds.AMD said they found that the company’s FX chips could reach over 5 GHz using normal air cooling or water-cooling rigs that cost less than $100.Commenting on the record-setting feat, the overclocking review site Overclockers Club made note that only two cores were running throughout the overclock. Having the other cores disabled may have helped the frequency boost, it said, along with the temperature of -235 degrees C to keep the CPU chilled. Nonetheless, the site added that a dual core clocked at 8.429GHz is still an AMD triumph.Similarly, another site, Overclockers, said the record numbers spell only the beginning and that, looking forward, one might wonder what about 9 GHz. “Pre-production chips historically only scratch the surface of what the architecture is capable of. Given time as fabrication processes and yields improve while more people get their hands on more chips, we could hear reports of AMD seriously flirting with 9 GHz soon enough.” The AMD press statement said that, beside setting world records, the AMD FX processor will enable an “unrivaled enthusiast PC experience” for the money, including extreme multi-display gaming and HD content creation. AMD Releases Athlon 64 FX-60 Dual-Core Processor Explore further (PhysOrg.com) — AMD has set the world record of fastest CPU with a speed frequency of 8.429 GHz, winning the company a place in the Guiness World Records. AMD’s yet-to-ship Bulldozer-based FX chips drew the Guinness ranking for the “Highest Frequency of a Computer Processor.” The AMD-FX CPU is set to debut in Q4 2011. © 2011 PhysOrg.com Citation: Team AMD FX sets Guiness record (2011, September 14) retrieved 18 August 2019 from https://phys.org/news/2011-09-team-amd-fx-guiness.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. Announced yesterday, the Guiness record news drew kudos and comments from a wide range of sites that closely follow news and events circling rivals AMD and Intel. Some reports noted the timing of AMD’s announcement was made on the opening day of the Intel Developer Forum in San Francisco.The record was actually set at an event in Austin, Texas, on August 31. A special team had been assembled at the Texas event made up of expert overclockers along with AMD technologists and were dubbed Team AMD-FX. Their goal was to attempt record numbers by “overclocking” 8-core AMD FX desktop processors. More information: Press release
More information: Yves-Alexandre de Montjoye, César A. Hidalgo, Michel Verleysen, and Vincent D. Blondel. “Unique in the Crowd: The privacy bounds of human mobility.” Scientific Reports. DOI: 10.1038/srep01376 As the focal point of their paper, the researchers used these results to develop a mathematical formula that tells the probability of uniquely identifying an individual based on the data’s temporal and spatial resolution. Essentially, they found a formula for estimating privacy. Don’t stop anonymizing data 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. Copyright 2013 Phys.org All rights reserved. This material may not be published, broadcast, rewritten or redistributed in whole or part without the express written permission of Phys.org. These results highlight the potential risk to individual privacy and anonymity from mobility data combined with publicly available information. The researchers hope that the findings will help inform the design of future policies and technologies.”Our results help us understand what is possible and what is not possible,” de Montjoye told Phys.org. “We all have a lot to gain from this data being used. Our formula allows us to estimate privacy, so now the question is how do we use it to balance things out and make it a fair deal for everybody?”In the future, de Montjoye plans to continue to investigate the consequences of what large amounts of personal data mean for an individual’s privacy. “Another area we want to pursue is to apply this same methodology to other sources of human-generated data,” he said. Journal information: Scientific Reports (Phys.org) —While most people know that using a cell phone means that the phone’s location is being recorded, a new study has revealed just how little information is required to determine an individual’s personal identity. By analyzing 15 months of cell phone mobility data from 1.5 million people, researchers have found that only four spatio-temporal points (an individual’s approximate whereabouts at the approximate time when they’re using their cell phone) are all that’s needed to uniquely identify 95% of the individuals. The study has implications for modifying privacy law in order to keep pace with technological advances. An artistic representation of being “unique in the crowd,” representing the new finding that human mobility traces are highly unique, and mobility data can be used to reconstruct individuals’ movements in space and time. The original photo is on the right. Credit: Yves-Alexandre de Montjoye, et al. Original image “Grand Central Station” by theotter The researchers, Yves-Alexandre de Montjoye at MIT in Cambridge, Massachusetts, and Université Catholique de Louvain in Belgium, and his coauthors, have published their paper in Nature’s Scientific Reports on how cell phone data places fundamental constraints on the privacy of an individual’s mobility traces.The reason that four locations are sufficient to identify most people is simply that human mobility is unique. Just as how everyone has unique fingerprints, everyone has unique daily travels. In the case of fingerprints, Edmond Locard showed in 1930 that only 12 points are needed to uniquely identify a fingerprint. Likewise, the researchers’ data shows that just four spatio-temporal points are needed to uniquely identify the mobility trace of an individual. In other words, it’s not likely that someone else will be in the same locations as you are at four different times of day. In fact, the researchers found that knowing just two randomly chosen points can uniquely identify more than 50% of the individuals.As the researchers noted, these four points that allow for the identification of individuals could come from information that is publicly available, such as the individual’s home address, workplace address, or Twitter posts. One might expect that the data would provide more anonymity by decreasing the resolution of the data, which is done by increasing the time range from one hour to several hours and increasing the spatial range from a few square meters to several hundred square meters. As an analogy, decreasing the resolution of a photograph causes people in the photograph to appear blurry and unidentifiable. But this is not what happens when decreasing the resolution of mobility data. Surprisingly, the researchers found that decreased resolution does not make the data that much more anonymous; a few more pieces of information are all that is needed to identify individuals. Citation: Study shows how easy it is to determine someone’s identity with cell phone data (2013, March 25) retrieved 18 August 2019 from https://phys.org/news/2013-03-easy-identity-cell.html The unique traces of mobile phone users, along with the information that can be inferred from them, highlight the importance of understanding the privacy bounds of human mobility. Credit: Yves-Alexandre de Montjoye, et al.
More information: Astronomy & Astrophysics, www.aanda.org/articles/aa/pdf/ … 15/11/aa27274-15.pdf 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. (Phys.org)—Exoplanet hunters have so far found hundreds of alien worlds using the transit method. They observe the visual brightness of the star, which drops when a planet crosses in front of the parent star’s disk. However, only a handful of grazing exoplanets—meaning exoplanets that partially transit the host-star’s disc—have been detected and confirmed. Astronomers from the University of Porto in Portugal blame giant dark polar spots on host stars for the difficulties of finding new grazing planets. Their research appears in the November issue of Astronomy & Astrophysics journal. Journal information: Astronomy & Astrophysics © 2015 Phys.org Explore further Astronomers find ‘cousin’ planets around twin stars Schematic view of a grazing planet occulting a polar spot. Credit: M. Oshagh et al. Citation: Astronomers explain the low number of discovered grazing planets (2015, November 9) retrieved 18 August 2019 from https://phys.org/news/2015-11-astronomers-grazing-planets.html When a planet passes in front of a star, it blocks out a tiny portion of the star’s light, reducing its brightness. If the planet, during its transit, does not fully cover the stellar disk, the planetary transit is said to be grazing. While astronomers have discovered plenty of planets, detecting them as they pass in front of a star, only eight have been detected by partial transit of the star’s disk. For example, one of the grazing exoplanets is WASP-67 b, which was detected in 2011. This planet is known to undergo only partial eclipses and its grazing nature was confirmed by a detailed study. The lack of second and third contact makes WASP-67 b hard to track down and complicates accurate measurements of its physical parameters.Prior to the newest research conducted by astronomers from the University of Porto, there has been no study explaining why only so few grazing planets have been discovered. In the new paper, the researchers explore possible explanations for this phenomenon. They point to dark giant polar spots on the host stars.”Our hypothesis to explain the insufficient number of grazing planets is based on the assumption that many grazing planets transit host stars with a dark giant polar spot. As a consequence, the transit light curves disappear due to the occultation of the grazing planet and the polar spot,” the researchers wrote in the paper.Large, dark spots located near the stellar rotational axis, either at high latitude or covering the pole, are common features on stars. They are usually much cooler than the stellar photosphere. The occultation of these dark stellar spots by a planet can generate anomalous results when using the transit method and may lead to an incorrect estimate of the planetary parameters.”If a grazing planet crosses a large polar spot, then the transit depth decreases significantly, considering that the limb-darkening also causes a decrease in the transit depth when compared to a central transit,” the scientists explain.They assume that this leads to a lower signal-to-noise ratio and may cause the transit signal to be below the detection threshold. The signal could be even completely missed. If so, there should be many more planets yet undetected, including planet candidates that were discovered by NASA’s Kepler spacecraft, known as the Kepler Object of Interest (KOI).”We found that more grazing planets should have been detected than have been detected,” the paper reads.The list of detected KOIs could contain many grazing planet candidates, but they have yet to be confirmed. The researchers conclude that at least some of them should be real, and if confirmed, they will partially fill the observed gap of grazing transiting planets. They encourage exoplanet hunters to perform more careful analyses when using grazing transit method in the future.
Journal information: Science Advances Oscillating flow and light pulses can be used to create reconfigurable architecture in liquid crystals. Materials scientists can carefully engineer concerted microfluidic flows and localized optothermal fields to achieve control on nucleation , growth and shape of such liquid domains. In comparison, pure liquids in thermodynamic equilibrium are structurally homogeneous. Experimental work based on theory and simulations have shown that if the liquids are maintained in a controlled state of nonequilibrium, the resulting structures can be indefinitely stabilized. Sculpted liquids can find applications in microfluidic devices to selectively encapsulate solutes and particles into optically active compartments to interact with external stimuli for a variety of medical, healthcare and industrial applications. In a recent study published in Science Advances, Tadej Emeršič and co-workers in Slovenia and the USA developed pure nematic liquid crystals (NLC), where they dynamically manipulated defects and reconfigurable states of the materials by the simultaneous application of multiple external fields. Solid materials can exhibit distinct structural phases simultaneously, a property that can be manipulated to engineer functionality. However, in pure liquids at equilibrium, such structural phases that correspond to grain boundaries and defects do not arise. While liquids exhibit a number of attractive features including the ability to wet surfaces, demonstrate high diffusion coefficients and absolute compliance, it is challenging to include additional functionalities to liquids due to their inherent homogeneity. Complex behavior is observed in multicomponent synthetic and biological mixtures and the resulting structures are difficult to manipulate since they occur in out-of-equilibrium situations. Such situations generally involve multiple components with sharp miscibility and gradients between hydrophilic and hydrophobic domains as well. , Reviews of Modern Physics In the study, the flow-aligned dowser state was stable under strong flows but unstable in weak flow. Depending on the flow velocity, the dowser domains could grow and shrink in the experiments as seen in numerical simulations. The scientists calculated the criteria for growth and shrinking of domains in time and indicated how the domains grew, shrunk or annihilated along the channel.By carefully applying the laser tweezers, the scientists showed that a steady stream of domains could be produced by dissecting the original bulk dowser with a moving laser spot, where the laser melted the sides of the material’s phase boundary. A growing domain at higher flow velocity could thus be split longitudinally in half, with a static laser beam at low light intensities. The laser tweezers allowed dynamic control of the size, number and lifetime of generated dowser domains, which were further manipulated by modulating the periodic flow velocity. For instance, under uniform flow, the dowser field aligned uniformly along the direction of flow to either grow or shrink, depending on the regime of the velocity. The scientists were able to tune and actively control the flow as a constant-sized domain that could be stably maintained for more than ten seconds. Explore further Growing and shrinking dowser domains in numerically simulated nematic microflows. Simulation of a laser-induced defect loop in a channel either undergoing expansion or shrinkage, subject to a strong or a weak pressure-driven flow. Top: top view of the channel showing defect loop. Bottom: side view showing the evolution of dowser structure. Elastic constants of 5CB are adopted in the calculation. Credit: Science Advances, doi: 10.1126/sciadv.aav4283 The work represented an ideal experimental model of a quasi-two-dimensional (2D) orientation material phase. In the initial stationary state within a microfluidic channel, the heated material appeared black. When the flow was turned on, depending on the velocity of flow, the birefringent appearance changed from black to bright colors. The flow aligned domains evolved in this way to either grow or annihilate with flow velocity. The materials scientists named the flow regime the ‘bowser state’ due to the bowed profile of the material and the flow aligned state as the ‘dowser state’ due to its analogy to the so-called dowser field in nematostatics, where nematostatics is the charge density of elastic nematic materials, analogous to electrostatics. The dowser state has an anisotropic orientation with its own elastic behavior, topological defects and solitons (a solitary wave packet that maintains its shape while propagating at constant velocity). In comparison, the bowser state is effectively isotropic and simple in the simplified 2D view. The scientists were able to control the shape, splitting and coalescence of these phase domains. Emeršič et al. conducted all experiments at room temperature, driving and controlling fluid flow in the microchannel with a pressure-driven microfluidic flow control system. They studied the flow regimes, reorientation dynamics and flow-driven deformations of 5CB in the microchannels using polarized light microscopy. The scientists built laser tweezers around the inverted optical microscope with an IR fiber laser operating at 1064 nm as a light source, and a pair of acoustic-optic deflectors driven by a computerized system to precisely manipulate the beam. Producing a steady stream of dowser domains by chopping the bulk dowser state with a moving laser spot. By moving an isotropic island of laser-heated nematic phase transversely across the phase boundary between the dowser and bowser state (black) one can produce a uniform train of dowser domains. Recorded under crossed polarizers at 30 fps, the view field size is 480 µm × 120 µm. Credit: Science Advances, doi: 10.1126/sciadv.aav4283 , Physical Review Letters © 2019 Science X Network Furthermore, in the model developed by Emeršič et al., they showed how the flow direction could be reversed for the dowser domain, leading to a rapid reversal of orientation from the previous state of equilibrium. In addition, the dowser field could couple to external magnetic and electric fields and gradients of the channel thickness to determine the control, flow steering and optical tuning of the 5CB nematic material. The scientists observed the direct response to the external stimuli clearly through birefringence in the study and determined this to be a suitable method to measure the viscoelastic and rheological properties of the material. Emeršič et al. envision the possibility of conducting chemical reactions in such enclosed volumes in practice, as previously shown with liquid crystal templates. In addition to that, based on the principles outlined by Emeršič and co-workers, a 3D printing system can be engineered to contain liquids, within which complex and out-of-equilibrium structures can be created and stabilized. The experimental models developed in this study using standard thermotropic LCs are also transferrable to active and biological materials with nematic behavior. The proposed and demonstrated method is a technical tool in materials science, with potential applications in biophysics, chemistry and chemical engineering. Multimaterial 3-D laser microprinting using an integrated microfluidic system Nematic liquid crystals (NLCs) are the simplest form of liquid crystal molecules without orderly positions, and they differentiate from pure liquids at the level of the molecular orientation. NLCs have a range of properties that allow them to serve as microreactors and conduct inherent polymerization reactions for intriguing future applications. Current work in the field is still experimental, for example, nematic flows in microfluidic environments, which highlight the potential cross-talk between topological defects in different fields of velocity and molecular orientation. In this work, the scientists observed the phase interface with NLCs for the first time, experimentally accomplished by generating polar-phase domains that were controlled by combining microfluidic confinement, fluid flow rates and laser pulses in practice. Emeršič et al. used the single-component nematic material pentyl-cyanobiphenyl (5CB) in all experiments performed in linear microfluidic channels with a rectangular cross-section. The scientists fabricated the channels with polydimethylsiloxane (PDMS) relief and indium tin oxide (ITO)-coated glass substrates using standard soft lithography procedures. They then filled the microfluidic channels with 5CB in its heated isotropic phase and allowed it to cool down to the nematic phase, before beginning the flow experiments. The scientists also chemically treated the microchannel walls to engineer a strong homeotropic surface to anchor the 5CB molecules. 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. Expansion and contraction of laser-nucleated dowser domains in a moderate nematic microflow. The lifetime of the domain is proportional to the critical velocity and the initial size. Recorded under crossed polarizers at 30 fps, the view field size is 480 µm × 120 µm. Credit: Science Advances, doi: 10.1126/sciadv.aav4283 Nucleation of orientation phase domains in pressure-driven nematic microflows. (A) Schematic illustration of a channel with homeotropic anchoring on the top and bottom surfaces used in the experiment; IR, infrared; ITO, indium tin oxide. (B) The nematic in a channel looks black between crossed polarizers in the absence of flow and gains visible birefringence due to flow-driven director distortion that traps a domain of the flow-aligned state (also called the dowser state from here on); n denotes the nematic director. Strongly absorbed light of the laser tweezers heats the NLC, creating an isotropic (Iso) island that is quenched into the nematic (N) phase when the laser is switched off. The dense tangle of defects coarsens into a single defect loop that traps a flow-aligned dowser state, identifiable as a green area at low velocity. (C) The laser-induced nucleation of dowser domains can be automated and their shape can be dynamically controlled by tuning the flow parameters. Crossed double arrows indicate the orientation of the polarizers. White empty arrows in the bottom left corners indicate direction and qualitative velocity of the flow throughout the paper. Credit: Science Advances, doi: 10.1126/sciadv.aav4283 , Nature Materials Citation: Sculpting stable structures in pure liquids (2019, February 21) retrieved 18 August 2019 from https://phys.org/news/2019-02-sculpting-stable-pure-liquids.html Systematic reshaping of dowser domains under laser action and oscillatory flows. (A) Moving the laser beam transversely across the bulk dowser pinches off a uniform “train” of the domains. (B) A static beam at a low power of 80 mW generates a small isotropic region that cuts a large dowser domain longitudinally in half. (C) The shape and size of the domain can be maintained over long time and length scales by periodically modulating the driving pressure around the value that induces the desired average flow rate. (D) Under an alternating flow, a dowser domain reverses orientation every time the flow direction is changed. The reorientation creates surface point defects and realigning fronts, visible under the microscope as a rapid color change. The energetically unfavorable “old” orientation shrinks into a narrow 2π soliton and pinches the domain boundary (black arrows). (E) Sufficiently rapid flow reversal creates point defect pairs connected by solitons. With the flow turned off, the characteristic length goes to infinity, and the solitons expand, revealing their signature profile in transmitted light intensity (inset). In a slow residual flow, flow-aligned parts shrink more slowly than parts with unfavorable orientation. Scale bars, 20 μm. Credit: Science Advances, doi: 10.1126/sciadv.aav4283 Scientists have developed active matter in the form of living colonies and bioinspired synthetic counterparts. They printed hydrophobic/hydrophilic domains on to liquid mixtures by relying on surfactant nanoparticles and controlled non-equilibrium systems to demonstrate the motion and transition between different rheological regimes. Liquid crystals (LCs) are an ideal system to study the phenomena of interest, such as spontaneous symmetry breaking, topological defects, orientation ordering and external stimuli based phase transitions. More information: Tadej Emeršič et al. Sculpting stable structures in pure liquids, Science Advances (2019). DOI: 10.1126/sciadv.aav4283Xiaoguang Wang et al. Topological defects in liquid crystals as templates for molecular self-assembly, Nature Materials (2015). DOI: 10.1038/nmat4421Anupam Sengupta et al. Liquid Crystal Microfluidics for Tunable Flow Shaping, Physical Review Letters (2013). DOI: 10.1103/PhysRevLett.110.048303Gareth P. Alexander et al. Publisher’s Note:Colloquium: Disclination loops, point defects, and all that in nematic liquid crystals [Rev. Mod. Phys.RMPHAT0034-686184, 497 (2012)], Reviews of Modern Physics (2012). DOI: 10.1103/RevModPhys.84.1229
After a dog attack in the park, you may link the event to the barking (i.e., cue), and therefore fear the barking of a dog, or to the park (i.e., context), and therefore fear the park where the attack took place. This research explored whether acute stress may affect the balance of learning to associate fear with cues versus with contexts. Participants underwent either a task designed to induce stress or a neutral task. Afterward, in a fear-learning task, participants explored a computer-game-like virtual environment with three rooms. In one of the rooms, participants would receive mild shocks to their leg whenever a light came on. After the fear-learning task, participants had to explore each room again, with the light in a different room, but did not receive shocks. Throughout this procedure, the researchers measured skin conductance responses, a measure of fear. Participants who were not under stress before the fear-learning task learned to associate fear with the cue (i.e., the light) and with the context (i.e., the room), whereas participants under stress associated fear with only the cue. Acute stress also caused participants to keep responding with fear to the light, even when the light appeared in a different room and they did not receive more shocks. These findings indicate that acute stress may enhance fear in response to cues (e.g., fear after hearing a dog bark) and impair the association with a context (e.g., fear in the park where a dog attack took place). This finding may help to better understand fear-related disorders, such as posttraumatic stress disorder, in which fear is decontextualized but triggered by single cues and in which stress is a major factor. Fear Without Context: Acute Stress Modulates the Balance of Cue-Dependent and Contextual Fear LearningKathrin Simon-Kutscher, Nadine Wanke, Carlo Hiller, and Lars Schwabe People’s evaluations of the severity of harm transgressions (e.g., violence, maltreatment) seem to depend on their frequency and magnitude, whereas their evaluations of purity transgressions (e.g., sacrilege, deviant sexual acts) are less affected by frequency and magnitude, this study suggests. Participants evaluated how morally wrong harm and purity transgressions were. These transgressions varied in frequency or magnitude (e.g., a person has intercourse with a goat once vs. frequently; a person throws a small vs. a large rock at a farm animal). Harm transgressions that were more frequent or larger were judged as more morally wrong than rare or smaller harm transgressions. In contrast, the dosage of purity transgressions did not seem to affect how morally wrong they were judged to be. Results similar to these were obtained in another experiment in which the dosage variations were miniscule (e.g., “Alice consumes a one-millimeter- vs. one-centimeter-thick piece of flesh from her neighbor’s corpse”). Rottman and Young suggest that this dosage insensitivity in the purity domain may lead people to misconstrue the impact of their “purity-based” choices (e.g., feeling licensed to pollute a river that is already slightly polluted). Specks of Dirt and Tons of Pain: Dosage Distinguishes Impurity From Harm Joshua Rottman and Liane Young Read about the latest research published in Psychological Science: Variation in the μ-Opioid Receptor Gene (OPRM1) Does Not Moderate Social-Rejection Sensitivity in HumansEmil Persson, Erkin Asutay, Markus Heilig, Andreas Löfberg, Nancy Pedersen, Daniel Västfjäll, and Gustav Tinghög Genetic variations of the μ-opioid receptor are related to individual differences in physical pain sensitivity, and some research suggests that they might also underlie differences in sensitivity to social rejection. This research suggests that the latter link may be weaker than previously thought. A sample of 490 adults were genotyped for the A118G variation of the μ-opioid receptor gene and divided into two groups: individuals carrying G alleles (i.e., with G/G or A/G alleles) and individuals with A/A alleles. All participants played Cyberball, a game in which they competed against virtual players who, in an exclusion version of the task, stopped passing a ball to the participant, provoking feelings of social exclusion. Participants then rated their social distress after being excluded and responded to a survey that assessed their dispositional sensitivity to social rejection. Contrary to previous studies in which participants with the G alleles seemed to be more sensitive to social rejections, results indicated that genetic variation of the μ-opioid receptor did not predict sensitivity after exclusion in the Cyberball game or dispositional sensitivity to social rejection. In a series of decision-making games, the researchers also investigated whether G allele carriers would be more generous but more concerned about betrayal and more negative after unfair treatment than A allele carriers. In these games, real money was allocated to participants and more money could be earned by interacting with others, but no differences between participants emerged. These findings may help to exclude genetic variability of the μ-opioid receptor as an explanation for different levels of sensitivity to social rejection, which represents a major threat to an individual’s physical and mental well-being.
Shares of three listed state-owned oil marketing companies (OMC) fell up to 4 per cent at close on Tuesday, after the government raised excise duty on petrol by Rs 2.25 per litre and by Re 1 a litre on diesel.Bharat Petroleum Corporation fell by 4.06 per cent to close at Rs 712.90, while shares of Indian Oil Corporation fell by 2.55 per cent to Rs 351.20 on the Bombay Stock Exchange (BSE). Shares of Hindustan Petroleum Corporation Ltd lost 1.60 per cent to Rs 594. The second excise duty hike in three weeks will help raise additional Rs 4,000 crore in four months to March as the government seeks to take advantage of a slump in world oil prices to shore up its revenues without stoking inflation.
Kolkata: With a high demand of tickets for Friday’s IPL match between Kolkata Knight Riders (KKR) and Sunrisers Hyderabad (SRH), the police have taken necessary steps to check black marketing of tickets.At the same time, major steps have been taken to avoid betting at certain parts of the city and its adjoining areas.It may be mentioned that a few youths were arrested a few days ago, when they were found selling tickets of a match at a premium in Maidan area and the police had seized 20 tickets from them. Also Read – Heavy rain hits traffic, flightsThe police have intensified vigil in different parts of the city and steps have been taken so that the black marketers cannot take advantage of the increase in demand for tickets for Friday’s match.Policemen in plain clothes will be posted at different parts around the stadium. The policemen will be keeping a watch to ensure that no one can sell tickets at a premium to make fast money.Sources said that officers of the Anti-Rowdy Squad (ARS) are also maintaining vigil at different parts of the city to ensure that people involved in betting rackets cannot function. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedAt present, the police also need to maintain vigil to avoid online betting as well. The police had earlier arrested a few who used to run rackets involved in online betting and are taking all necessary steps to ensure that online betting does not take place.According to a police officer from Kolkata Police, different sections of the city police will work together to ensure that the IPL match passes peacefully without any untoward incident.While ARS and other departments of Kolkata Police will maintain vigil to check black marketing and cricket betting, a large contingent of police will get posted to ensure that safety and security of people coming to the stadium to watch the match. Policemen of all ranks will remain posted in and around the stadium so that people do not face trouble while watching the match and while leaving the place as well. People have to walk up to the entry of the stadium through proper channels and there are separate arenas for parking of vehicles as well.Traffic police will also be playing a vital role on Friday, as thousands of people will be approaching the stadium at a time. Traffic sergeants will ensure that no traffic congestion takes place in the city and moreover, there will be movement of many VVIPs in the city.
Kolkata: A number of colleges affiliated to Calcutta University have written to the varsity, urging it to extend the admission dates.There are 1.3 lakh seats in colleges under CU, out of which 40,000 are lying vacant, even though the last date for admission has already elapsed on July 10.According to sources in Calcutta University, seats have been lying vacant in a number of colleges, including Sris Chandra college, North City College, South City College, Dum Dum Motijhil College, Lake Town College and Bidhannagar College to name a few. Also Read – 2 Group D staffers held for ‘assaulting’ minorsInitially, the date for completion of admission was fixed on July 6 and was later extended to July 10 in the wake of allegations of extorting money for college admission.These colleges have written to the university with the appeal to extend the dates further.It may be mentioned that the Higher Secondary examination results were published in the first week of July and the admission process was kicked off on June 21.However, soon after the admission process began, there were allegations of extortion in the name of admission from a number of colleges in the city, including Surendranath College, Jaipuria College, South City College, Dinabandhu Andrews College, etc. Also Read – Naka checking to be stricter to rein in speed demonsSimilar allegations also surfaced from colleges in North 24-Parganas, affiliated under West Bengal State University.Chief Minister Mamata Banerjee instructed the state Education department to admit students online, so that they no longer need to turn up physically for the purpose.The police have also cracked the whip and arrested a number of people including students, for being involved in this unfair practice.”We have found out that the colleges located close to railway stations in the suburbs of the city already have their seats filled up,” a senior official of CU said. He expressed his optimism that if the dates are extended then seat occupancy will normalise.