August 2019

first_img Diamond-based light sources will lay a foundation for quantum communications of the future (PhysOrg.com) — “We have shown for the first time, theoretically, that a single molecule can behave as a perfect mirror,” Mario Agio tells PhysOrg.com. “Imagine that your mirror at home becomes a single molecule and that you put a strong lens between you and it. Well, you could still see the image of your face reflected…[A]mazing if you think that a molecule is just about a nanometer in size.” 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. Agio is a scientist at the Nano-Optics Group headed by Vahid Sandoghdar at ETH Zurich, Switzerland. Sandoghdar’s team investigates both theoretically and experimentally how light interacts with nanoscale objects. “Theoretically,” Agio says, “we show that a directional dipole wave can be reflected by one point-like oscillating dipole.” The results of the work done by the Group, including Gert Zumofen and Nassiredin Mojarad, can be seen in Physical Review Letters: “Perfect Reflection of Light by an Oscillating Dipole.”“There are many possibilities for this kind of work,” Agio points out. He explains that, “Once you can realize efficient coupling between a photon and a molecule or atom in free space, there is a great deal that you can do. For example, advanced solar cells, spectroscopy, quantum communications and quantum computation would all benefit from stronger interaction between light and matter.”However, there are some technical problems that need to be overcome in the lab. One of the more pressing issues is the fact that molecules behave like strongly damped oscillators at room temperature. “We need to cool the system to very low temperatures,” Agio says. Referring to work published earlier this year in Nature Physics (“Efficient coupling of photons to a single molecule and the observation of its resonance fluorescence”), he continues: “Indeed, our experiments have been able to achieve 12 percent extinction of light in the forward direction by a single molecule.Agio also explains that there are problems with being able to focus. “The reflection is only 100 percent if you can create a focused beam with lenses that just are not available today. But a terrific 80 percent reflection should be possible even with today’s conventional lenses and laser beams.”Sandoghdar’s group has been considering future developments for this work, and Agio discusses some of the possibilities. “We are considering the use of optical antennas to overcome the limitations of focusing. We should be able to channel and collect light more efficiently, improving the coupling between a photon and a single molecule, very much in the same way the antenna in your cell phone receives and send calls.” He pauses before adding: “We’d have to make it very small, though, scaling everything down to optical frequencies is challenging.” Agio is optimistic. He points out that the group has already done some work along the lines of optical antennas, and that it, too, has been reported in Physical Review Letters. “We have already shown experimentally that noble metal nanoparticles are very efficient optical antennas for single molecules,” he says, referencing an article titled, “Enhancement of single molecule fluorescence using a gold nanoparticle as an optical nano-antenna.” “Now,” he continues, describing the next steps, “we are working on how to combine the focusing with the antenna to make all of this workable.”More Information: G. Zumofen, N. M. Mojarad, V. Sandoghdar, and M. Agio. “Perfect Reflection of Light by an Oscillating Dipole,” Physical Review Letters (2008). Available online: link.aps.org/abstract/PRL/v101/e180404.G. Wrigge, I. Gerhardt, J. Hwang, G. Zumofen & V. Sandoghdar. “Efficient coupling of photons to a single molecule and the observation of its resonance fluorescence,” Nature Physics (2008). Available online: www.nature.com/nphys/journal/v … n1/abs/nphys812.html.Sergei Kühn, Ulf Håkanson, Lavinia Rogobete, and Vahid Sandoghdar. “Enhancement of Single-Molecule Fluorescence Using a Gold Nanoparticle as an Optical Nanoantenna,” Physical Review Letters (2006). Available online: link.aps.org/abstract/PRL/v97/e017402. 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.comcenter_img Explore further Citation: Can a single molecule behave as a mirror? (2008, November 18) retrieved 18 August 2019 from https://phys.org/news/2008-11-molecule-mirror.htmllast_img read more

New theory proposed to explain Pioneer probe gravitational anomaly

first_img(PhysOrg.com) — Portuguese physicists might have finally solved the decades old mystery of why the Pioneer probes, launched in the early 70’s, haven’t been decelerating from the Sun’s gravitational pull at the rate expected; it seems it might be something as mundane as adding in the tiny forces that occur when minute traces of heat from the plutonium on board the probes bounce off their receiving dishes, creating a counterforce, which in turn, causes the craft to slow; if ever so slightly. Citation: New theory proposed to explain Pioneer probe gravitational anomaly (2011, April 27) retrieved 18 August 2019 from https://phys.org/news/2011-04-theory-probe-gravitational-anomaly.html The Pioneer anomaly, as it’s come to be known, has had physicists scratching their heads ever since an astronomer by the name of John Anderson, working for NASA’s Jet Propulsion Laboratory, back in 1980, noticed a discrepancy between the slowdown rate projections for the craft and the rates they were actually experiencing, which led to the basic question, how could both probes be slowing down faster than the laws of physics projected? Possible explanations ranged from unknown mechanical issues with both craft, to dark matter pushing back, to possible flaws in the physics theories themselves.But now, Frederico Francisco of the Instituto de Plasmas e Fusao Nuclear, Lisbon Portugal and colleagues, as they describe in their paper published in arXiv, seem to have solved the problem using a simple old technology. Suspecting that heat was involved, they started with follow-up work by Anderson in 2002 and Slava Turyshev in 2006, also from NASA’s Jet Propulsion Laboratories, who both showed that heat released from the plutonium onboard the spacecraft could very well explain a slowdown. Unfortunately, both concluded that such heat emissions could not possibly account for the amount of slowdown seen. But this was because neither man thought to consider the impact of heat hitting the backside of the satellite dish (antennae) and then bouncing back. Francisco and his team used a computer modeling technique called Phong shading to show how the flow of heat as it was emitted from the main equipment compartment could emanate outwards, eventually bouncing off the back of the dish, resulting in just enough counterforce to explain the gravitational discrepancy.Case closed, as far as Francisco et al are concerned, but of course this being science, others will have to replicate the results before any sort of consensus can be found. © 2010 PhysOrg.com TPS Enables Study Of Mysterious Pioneer Anomaly More information: Modelling the reflective thermal contribution to the acceleration of the Pioneer spacecraft, arXiv:1103.5222v1 [physics.space-ph] arxiv.org/abs/1103.5222AbstractWe present an improved method to compute the radiative momentum transfer in the Pioneer 10 & 11 spacecraft that takes into account both diffusive and specular reflection. The method allows for more reliable results regarding the thermal acceleration of the deep-space probes, confirming previous findings. A parametric analysis is performed in order to set an upper and lower-bound for the thermal acceleration and its evolution with time. Schematics of the configuration of Lambertian sources used to model the lateral walls of the main equipment compartment. Image credit: arXiv:1103.5222v1 [physics.space-ph] http://arxiv.org/abs/1103.5222 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. Explore furtherlast_img read more

Al Qaeda suspects porn film found to contain treasure trove of secret

first_img Hide files within files for better data security Citation: Al Qaeda suspect’s porn film found to contain treasure trove of secret documents (2012, May 4) retrieved 18 August 2019 from https://phys.org/news/2012-05-al-qaeda-porn-treasure-trove.html The files were hidden in the video file through a process called steganography or concealed writing. The term steganography includes methods used for centuries, such as invisible ink, but now also includes techniques such as concealing (often unencrypted) content inside a digital image, video or audio file. Steganography conceals data within “plain sight,” which makes it difficult to detect.Digital steganography can be done on audio files by manipulating the waveform to hide data, but such changes produce noise that is more obvious than changes visible to the eye. Data can be hidden in image files opened in a text editor simply by inserting text at the end of the file, but more sophisticated and effective methods use special software to manipulate individual bytes or pixels of the media file. For example, readily available software can be used to manipulate the properties of individual pixels within an image. The color of pixels is determined by vector values representing the intensity of each color (red, green and blue in RGB systems, for example), and these values can be manipulated to hide data.Other steganographic software tools convert bytes of data to be concealed into individual binary bits (0 and 1) that are then substituted for the least significant bits in the media file. The substitutions are spread throughout the media file following a sequence or algorithm, to make detection more difficult and distortion of the media file less noticeable. Another, even more sophisticated method is to manipulate the discrete cosine transform coefficients (DCTs) used to compress JPEG files to hide data into parts of an image. This method enables the hidden data to survive even if the image is later cropped, resized or compressed.The forensic task of revealing data hidden within files is complicated because the area is rapidly developing and becoming ever more sophisticated, but security programs are available that can help researchers detect manipulations within images and other digital files.The researchers from the German Federal Criminal Police (BKA), spent many weeks examining the hidden pornographic video found on suspected Al Qaeda member, the Austrian Maqsood Lodin, when he was arrested in Berlin after returning from Pakistan. The video, called “Kick Ass,” was stored in a password-protected folder and within the video they found a file called “Sexy Tanja.” Further analysis of this file eventually revealed that it contained more than 100 concealed unencrypted documents describing Al Qaeda plans and operations. A video file has ample room for concealing documents, and would be relatively easy to distribute. In Maqsood Lodin’s memory stick, the porn video contained hidden terrorist training manuals in pdf form in English, German and Arabic, along with numerous documents detailing planned future Al Qaeda attacks, and lessons learned from previous operations. Lodin is currently on trial in Berlin, and has pleaded not guilty to charges of terrorism. 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. Explore further © 2012 Phys.Org A suspected member of the Al Qaeda terrorist group, arrested in May last year in Germany, was found with a memory stick hidden in his underwear. Police discovered the stick contained a password-protected folder with pornographic videos inside it, but suspicious computer forensic experts thought there must be more. After weeks of analysis, they determined that one of the pornographic videos contained concealed documents detailing Al Qaeda operations and plans.last_img read more

Scientists uncover clues to ATP mystery and how cells work

first_img Researchers uncover secrets of internal cell fine-tuning Although many parts of the cellular movement process are well-understood, there is still some mystery in the details. One mystery in particular is that long polymer chains of actin (called F-actin) have been observed to use ATP at a rate that is more than 40,000 times faster than that of individual monomers of actin (called G-actin). This gigantic rate difference has been experimentally investigated for more than 25 years without a solution.Now in a new paper in the Journal of the American Chemical Society, researchers Martin McCullagh, Marissa G. Saunders, and Gregory A. Voth at The University of Chicago have used quantum mechanics/molecular mechanics (QM/MM) simulations of G- and F-actin, guided by coarse-grained modeling, to investigate how the structural differences of the two types of actin may contribute to the rate difference at which they use ATP, a process called ATP hydrolysis.”I think this work provides a fundamental molecular understanding of how actin filaments catalyze ATP hydrolysis, which in turn is critical to their behavior,” Voth told Phys.org. “ATP hydrolysis modulates many actin properties, which in turn is very important to the behavior of the cellular cytoskeleton. Some of these properties are relevant to, e.g., the binding of anti-cancer drugs in targeting cancer cells.”In ATP hydrolysis, actin filaments use ATP by breaking off one of its three phosphate atoms. The chemical energy stored in the phosphate bond is released and can be used for many purposes. Here, the energy is used to change the properties of the actin filaments, after which the polymer can be disassembled. This continuous growth and disassembly is what causes cells to move. Basically, what the rate difference mystery means is that somehow actin polymerization accelerates ATP hydrolysis. In other words, as the actin forms a filament, the faster it can use ATP. The effect is cyclical, so that the higher the rate of ATP hydrolysis, the higher the rate at which actin can be depolymerized. This activity leads to a remarkable phenomenon called actin “treadmilling,” which is essential to cellular movement. Journal information: Journal of the American Chemical Society Water molecules can rotate more freely in G-actin than in F-actin. The F-actin snapshot (a) has a three-water wire, and the G-actin snapshot (b) has a six-water wire. Credit: McCullagh, et al. ©2014 American Chemical Society Citation: Scientists uncover clues to ATP mystery and how cells work (2014, September 23) retrieved 18 August 2019 from https://phys.org/news/2014-09-scientists-uncover-clues-atp-mystery.html 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. More information: Martin McCullagh, et al. “Unraveling the Mystery of ATP Hydrolysis in Actin Filaments.” Journal of the American Chemical Society. DOI: 10.1021/ja507169f Artistic rendering of the actin structures and free energy surfaces calculated for ATP hydrolysis in G-actin and F-actin, computed using QM/MM simulations. Credit: McCullagh, et al. ©2014 American Chemical Society The new QM/MM simulations help explain the dramatic rate increase of ATP hydrolysis that occurs in F-actin compared to G-actin. The simulations show that certain key amino acids change position during polymerization, which promotes the rearrangement of nearby water molecules. The water molecules can rotate more freely, allowing them to easily align into shorter “water wires” that transport protons through the water very quickly—almost instantaneously, in fact. The resulting ease with which the protons can move corresponds to a lowering of the free energy barrier of that process. Since proton transport is a key step in ATP hydrolysis, overall less energy is required for F-actin to hydrolyze the ATP molecules.The simulations reveal a barrier height reduction that agrees well with the experimentally measured value, supporting the explanation that the favorable proton transport environment in F-actin plays an important role in the increased ATP hydrolysis rate. “There are many, many proteins that utilize ATP (or GTP) hydrolysis for modulate their behavior,” Voth said. “I think this work opens up the possibility to include that process more routinely in the computational study of proteins.” (Phys.org) —Strong, thin fibers called microfilaments, or actin filaments, are present in the cytoplasm of almost every cell in the body. By growing and shrinking, actin filaments play a major role in cellular movement. Since these processes require large amounts of energy, actin filaments use a lot of ATP (adenosine triphosphate), a molecule that is often called the energy currency of the cell. © 2014 Phys.orglast_img read more

first_imgWhen a seemingly innocuous image of a woodpecker stashing away its acorn supply made the internet rounds, Twitter-users expressed revulsion. They weren’t reacting to the bird or the actual acorns, but to the set of holes in which the bird was storing its treasure. Clustered in an irregular pattern, the holes were triggering a condition called trypophobia. So why is this phobia so common? Scientists are still trying to answer this question, but many believe the aversion is evolutionarily adaptive. “We know that this condition pre-existed the internet — although the internet may have exacerbated it,” Arnold Wilkins, a psychologist at the University of Essex, told Live Science.  “You avoid things that are likely to harm you,” Wilkins explained. To someone with this phobia, an otherwise benign – and even downright gorgeous – image can spark fear and disgust. These individuals aren’t just afraid of any hole they see. Trypophobia is characterized by an aversion to clustered patterns of irregular holes or bumps. The term seems to have been coined by someone in an online forum in 2005, though scientists say the condition has likely been around for much longer. The phobia isn’t an official disorder, meaning it’s not listed in the “Diagnostic and Statistical Manual of Mental Disorders,” but up to 10% of people report experiencing symptoms, which include anxiety, nausea and a “skin-crawling” sensation, Wilkins said, after viewing certain images. “It can be quite debilitating,” he added. In the first ever scientific documentation of trypophobia published in Psychological Science, Wilkins compared trypophobia-triggering images with pictures of poisonous animals, like the blue-ringed octopus. He and his co-authors found a similar distribution of spots, bumps or holes, as well as a similar level of contrast in the images. The researchers concluded that the phobia could stem from an evolutionarily adaptive aversion to poisonous creatures. Read the whole story: Live Sciencelast_img read more

Merging the sounds of spiritualism

first_imgThe Capital brought forth its spiritual side as Bhakti Sangeet brings different devotional streams together. Presented by the Delhi Government’s Department of Art, Culture and Languages and the Sahitya Kala Parishad, the second day (10 May) of the three-day festival saw different streams of truth merge together in expression. The performances by Shubha Mudgal and Mohammad Irshad regaled audience present over there. The day began with the Buddhist chanting of Bhutan  followed by the message of Krishna Bhakti by O S Arun and Mohammad Irshad then enamored the audience by rendering the pure kalams of Bulle Shah. Mudgal ended the evening singing from the school of Nirgun bhakti. Also Read – ‘Playing Jojo was emotionally exhausting’The first day of the festival witnessed the recitations from the Rig Veda by K Vasedevan Namboothiri, A M Kesavan and K Madhavan Namboothiri. The chanting from the Vedas was followed by the mystic Baul singing of Bengal by Parvathi Baul. More for the evening was Punjabi singer Hans Raj Hans crooning to the devotional Punjabi Sufi kalams, stirring the spiritual hearts of the audience and listeners.The festival  featured 14 devotional singers of different genres, including bhajans, the sufi qawwali tradition of India as well as the traditions of Krishna bhakti. Also Read – Leslie doing new comedy special with Netflix’Devotional music is one form of expression that can be found in every kind of civilization, society and tribe. Given the multiplicity of religious beliefs in India, it is no wonder that we have an extremely rich and versatile tradition of devotional music. We can find Bhakti Sangeet in every language we encounter and in every region we visit. We are a nation of spirituality and we have multifarious ways of professing our love to God. Bhakti Sangeet is unique as it brings together all different genres of devotional music prevalent in India on one stage’, says Rinku Dugga, Secretary, Department of Art, Culture and Languages, Govt of Delhi. It was our bhakti and sufi saints who laid the foundation of our composite culture and the festival  was an ode to it.last_img read more

Indulge your fantasy

first_imgThe Collectors Heritage, a one of a kind homedecor showroom in Noida offers products that transport you into the medieval era simulating the  environment of a museum. We had a talk with the firm’s CEO, Sugandh Windlass, read on as to what she had to say: How and why did you get involved with such a project? And tell us a bit about yourself and your involvement with Collector’s HeritageCollectors Heritage is a brand of the Windlass Group of Companies which is a family owned business. Windlass Steelcrafts the parent company was started by my grandfather in 1942 and since then we have been exporting all our products. We launched Collectors Heritage in 2012 to start selling our products in India. Also Read – ‘Playing Jojo was emotionally exhausting’Is this something that always fascinated you or was the interest more recent?This field has always fascinated me. I am very interested in the manufacturing of swords. I was involved in the US operations of our company which is basically our marketing arm. We have two e-commerce websites. After working there for a while, I decided to start this e-commerce website in India and thereby branch into stores.With a decent number of museums in the country, why do you think a collection like this may attract people? Also Read – Leslie doing new comedy special with NetflixI feel that with the number of museums in the city, people will be more interested in our products. Everyone wants to take a walk down memory lane. All our products have a history. These are very products which you can see in a museum but not buy. However, with our store you can actually buy these products.How affordable or not affordable are the works and who exactly is your target audience/customer?All our products are meant for collectors who understand the product and does not mind spending. The price points range from Rs.2000 to Rs 20,000. We have products for Rs.700 and also for Rs.1.5 lacs. Our target customer is anyone who has an eye for unique products. Why do you think a concept like this might work here? All of our customers love to know more about the products. People are always looking for something different and thats what makes our products work. The biggest loophole that we have fixed is that we have mounted our swords permanently as swords cannot be sold. We have mounted them to make them into wall decorations, so that they cannot be called weapons.last_img read more

Screening the journey

first_imgThe Indira Gandhi National Centre for the Arts (IGNCA) Film Circle screens two films a month on the second and fourth Friday. This friday IGNCA screened the film Ustad Asad Ali Khan – A Portrait, directed by Renuka George.The 70 minutes film revolves around Asad Ali Khan Khan (1937-2011), the eminent instrumentalist of Jaipur Beenkar gharana. He was one of the very few musicians to practice rudravina, an instrument now almost extinct.The documentary shares his journey that starts from Rampur, where his father was a court musician, to New Delhi where he lived until his death in June 2011. He shares with the complexities of practicing this rare instrument. A glimpse of what life must have been like in the court days, and how the artistes of that generation dedicated themselves to their art was shown.last_img read more

Africa Summit Large parts of Capital to be nogo zones

first_imgThe residents of the national Capital will face traffic diversions and jams on Wednesday and Thursday as the Delhi Traffic Police has prohibited the entry of vehicles in the Lutyens’ zone along with other major areas of New Delhi district and central district during morning and evening hours for the India-Africa Forum Summit-2015. As a result, commuters have to follow the diversions that have been made on the busiest roads of the city.During movement of visiting dignitaries, roads like Sardar Patel Marg, Teen Murti Marg, Akbar Road, Tees January Marg, Rajesh Pilot Marg, Subrahmaniam Bharti Marg, Mathura Road, and Bhairon Road will remain closed on October 28 (from 5pm to 11 pm) and on October 29 (from 8 am to 10 am and 4 pm to 11 pm). Roads like Ring Road (between Bhairon Road and Raj Ghat), and Power Housing road leading to IG Stadium will also be closed. Also Read – Punjab on alert after release of excess water from Bhakra damApart from this, in order to avoid congestion in New Delhi area, entry towards New Delhi from Ring Road will be closed on Aurobindo Marg (from AIIMS crossing/flyover) towards Lodhi Road and Lala Lajpat Rai Marg from Mool Chand flyover (Ring Road) up to Lodhi Road flyover.On October 28, commuters coming from South to North and vice versa can take the Ring Road from Ashram Chowk – Sarai Kale Khan – IP Estate – Raj Ghat – ISBT Kashmere Gate. These roads have been marked as green corridor and will remain open to general traffic. “From Dhaula Kuan, Ridge Road is continuously available for movement towards Karol Bagh. Similarly, Mother Teresa Crescent will remain open,” Muktesh Chander, Special Commissioner of Police (Traffic) said. However, the movement on Sardar Patel Marg will be affected for a short duration, so the commuters will have to take upper ridge road and Park Street Road. Also Read – Union Min doubts ‘vote count’ in Bareilly, seeks probeFor East-West movement, Barapulla Road, Lodhi Road, Safdarjung Road, Kamal Ataturk Marg, Mother Teresa Crescent are available. But these roads are likely to witness heavy traffic due to its vicinity to the closed roads. “Apart from the diversion boards, around 4,500 traffic policemen will be deployed in the area to guide the commuters on diversions. Usually there are 3000 traffic cops deployed in these areas but additional 1500 traffic cops will be deployed,” Chander added.North-bound traffic on Ring Road will be diverted at Nizamuddin Bridge to cross the bridge, take Pushta Road near Akshardham and re-enter Ring Road either through Geeta Colony bridge or the bridge coming to ISBT Kashmere Gate.last_img read more

Sewage to potable water IITKgp alumni comes up with water recycling plant

first_imgKolkata: IIT Kharagpur is setting up the Aditya Choubey Center for Re-Water Research, seed-funded by its two alumni Anant Choubey and Aneesh Reddy to remediate, replenish and rejuvenate water resources.”The scarcity of water, both for domestic and drinking purposes, is becoming acute and will only worsen in the coming years. On the other hand, urban areas are witnessing massive sewage problems. The idea of linking these two crises and coming up with one viable solution was challenging. Having done that, we would be networking with government bodies to take up this technology and the process and meet the water challenge in various cities,” said Aneesh Reddy. Also Read – Rain batters Kolkata, cripples normal lifeThe Centre will come up with an on-campus plant which will daily convert 1.35 million litre of sewage water from the hostels to 1.2 million litre of potable water.The pilot plant at the institute is expected to be ready by March 2019. The MoU was signed on Friday in presence of both the alumni on the occasion of 68th Foundation Day of the institute.The water processing and output will be monitored in real-time and conform to IS 10500-2012 standard for drinking water. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killed”We will conduct quality assurance tests demonstrating the suitability of the technology for treatment of sewage and consumption and infuse confidence among agencies and the public at large related to water supply and treatment,” said Prof M M Ghangrekar, faculty at the Dept. of Civil Engineering who will be heading this project. The researchers would also develop an operationally viable technology so that the plant can be profitably commercialized. According to Partha Pratim Chakrabarti, director, IIT KGP, the step is geared towards the challenge taken up by the institute to resolve two burning issues of urban India — sewage disposal and access to clean potable water.”We are looking forward to participatory models in villages to implement this technology. We would also engage international water experts and professionals from the industry as researchers and advisors in this Center. Aneesh and Anant will be advisers as well,” he said.last_img read more