Homo neanderthalensis, adult male. Credit: John Gurche, artist / Chip Clark, photographer New ancestor? Scientists ponder DNA from Siberia Explore further © 2010 PhysOrg.com (PhysOrg.com) — Following up on evidence that Homo Sapiens and Neanderthals mated and produced offspring, following the sequencing of the Neanderthal genome last year, Peter Parham, professor of microbiology and immunology at Stanford, set forth evidence in a presentation to the Royal Society in London last week that shows that humans benefitted from such encounters by having human leukocyte antigens (HLAs), added to their genomes, which in turn helped them to fight off diseases native to northern climates.
Developing seeds for growing whole gardens of identical SWCNTs Journal information: ACS Nano Citation: British team devises method for separating carbon nanotubes cheaply (2012, January 19) retrieved 18 August 2019 from https://phys.org/news/2012-01-british-team-method-carbon-nanotubes.html (PhysOrg.com) — When single walled carbon nanotubes (SWCNTs) are made, they come out in both metallic and semiconducting material form. Unfortunately, different applications require one or the other of these materials, but not both, which means they need to be separated. Even more unfortunately, efforts to do so have proven to be very expensive. Now, though, due to the efforts of a British team of physicists, as they describe in their paper in ACS Nano, a new method has been devised that allows SWCNTs to be separated cheaply enough to allow for bulk manufacturing. Explore further More information: Scalable Method for the Reductive Dissolution, Purification, and Separation of Single-Walled Carbon Nanotubes, ACS Nano, Article ASAP. DOI: 10.1021/nn2041494AbstractAs synthesized, bulk single-walled carbon nanotube (SWNT) samples are typically highly agglomerated and heterogeneous. However, their most promising applications require the isolation of individualized, purified nanotubes, often with specific optoelectronic characteristics. A wide range of dispersion and separation techniques have been developed, but the use of sonication or ultracentrifugation imposes severe limits on scalability and may introduce damage. Here, we demonstrate a new, intrinsically scalable method for SWNT dispersion and separation, using reductive treatment in sodium metal-ammonia solutions, optionally followed by selective dissolution in a polar aprotic organic solvent. In situ small-angle neutron scattering demonstrates the presence of dissolved, unbundled SWNTs in solution, at concentrations reaching at least 2 mg/mL; the ability to isolate individual nanotubes is confirmed by atomic force microscopy. Spectroscopy data suggest that the soluble fraction contains predominately large metallic nanotubes; a potential new mechanism for nanotube separation is proposed. In addition, the G/D ratios observed during the dissolution sequence, as a function of metal:carbon ratio, demonstrate a new purification method for removing carbonaceous impurities from pristine SWNTs, which avoids traditional, damaging, competitive oxidation reactions. It was only recently that a team at Stanford University devised a means for separating and sorting the two distinct forms of the SWCNTs, a breakthrough that had researchers dreaming of such exotic applications as artificial skin. Sadly though, the process they devised would have cost billions to produce just a kilo of the stuff, which of course very quickly put a damper on the development of applications.Now though, the team in Britain from London’s Imperial College, led by Milo Shaffer, has figured out a way to do the job cheaply, and it’s all due to researchers from another lab at University College, discovering that Buckminster fullerenes dissolve in ammonia. To develop the new process, teams from both labs worked together.The new process works like this. First the nanotubes are dissolved in a sodium and ammonia solution to purify and pull them apart, creating what they call a “nanotubide” solution; afterwards, the ammonia is removed. The result is a salt and nanotubide dry powder. The team then adds dimethylformamide to the powder which causes a portion of the salt-laden nanotubide to dissolve. By using just the right concentration in the original solution, the team has found that they can retrieve material that is mostly metallic SWCNT from the dissolved salt. And that, in all its simplicity, is pretty much all there is to it.Besides allowing for SWCNTs to be made cheaply, the new process also eliminate the need for using a centrifuge which was a part of the process used in earlier methods and sometimes caused damage to the final product. Also, because this new method appears to be ready to go as is, the team has already licensed it to Linde, an industrial gas company.This all means that those initial dreams of exotic products may now finally come to fruition, though of course, most of them, such as artificial skin, are still likely to be some ways off, as now that cheaply made SWCNTs can be had, there is still all the research ahead in actually using them to create such end products. © 2011 PhysOrg.com 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: Removing ‘black sheep’ could make Internet run more efficiently (2012, February 28) retrieved 18 August 2019 from https://phys.org/news/2012-02-black-sheep-internet-efficiently.html As a consequence, removing these black sheep links significantly increased the network’s transmission capacity. From a practical perspective, removing these few links is easier than redesigning the entire network or developing a complex routing strategy. However, the researchers noted that there is a limit to removing links, where removing too many will lower the overall efficiency.In their most recent study, the researchers show that, in order for this method to work effectively, the network structure must be heterogeneous in terms of node betweenness values. In other words, the method works best for networks that have nodes with a greater diversity of betweenness values. In this way, networks with large heterogeneity, which can be measured by the well-known Gini coefficient, have more significant effects.“Our recent paper doesn’t further improve network capacity of the method, but points out that heterogeneity of network structure is a necessary condition for the effect’s existence, highlights the rationality based on betweenness, and discusses the effect’s applications in engineering practice,” Zhang said. “It also shows that the greater the heterogeneity of a network is, the better the effect is. In essence, our method can reduce the heterogeneity, hence load balance, and then capacity is enhanced.”Because the black sheep links often use the highest bandwidths, removing them provides another advantage: it saves energy and reduces the cost of bandwidth, construction and maintenance. The researchers hope that the combination of increased transmission capacity and reduced cost will motivate the wide application of this method to a variety of communication and transportation networks.“Edge removal is only an abstract concept, it may have different forms in different contexts,” Zhang said. “Let me take urban transportation networks as an example: blocking the entrance ramp can relieve congestion and help traffic move more smoothly during rush hour. Here, blocking the entrance ramp logically means edge removal. For the Internet, building overlay routing is an important way to improve network reliability. This can be achieved by setting up relay nodes to obtain path diversity and enhance forwarding efficiency. A relay node needs to close some key links during heavy load. Closing links can be easily implemented and automatically finished by software. In the second instance, closing links mean edge removal. In a word, edge removal has many variants in practice.” © 2011 PhysOrg.com Greedy Routing Enables Network Navigation Without a ‘Map’ The researchers, Guo-Qing Zhang, Di Wang, and Guo-Jie Li, from the Chinese Academy of Sciences in Beijing, published the strategy in 2007. In their most recent paper, published in Scientia Sinica Informationis, they have continued to build on this idea by determining the necessary conditions for the effect’s existence.“Our main findings reveal the effect of enhancing network capacity of edge-removal in networks and the prerequisite of the effect,” Zhang told PhysOrg.com. “However, the results of capacity expansion depend on specific networks. For the popular BA model network, this method increases network capacity more than 10 times.”The Internet is a combination of many interconnected networks, each of which consists of nodes (e.g., computers and routers) and links (e.g., cables and optical fibers). Structurally, this framework is similar to all networks in areas as diverse as biology, sociology, and statistics. In the case of the Internet, data is stored as bits, and thousands of bits are combined in packets that are directed by routers to their destinations. Routers use certain strategies to get packets to their destinations as quickly as possible, sending them along links from one node to another in a split second.The many different strategies proposed so far for increasing the Internet’s transmission efficiency fall under two categories: developing better routing strategies and optimizing the network itself. The researchers from the Chinese Academy of Sciences show that modifying the network does not necessarily require a complicated redesign; instead, deleting just a few well-chosen links is relatively easy and effective.The key is choosing which links to remove. To do this, the researchers analyzed a network model that simulates packet traffic. In the model, routers use a shortest path routing strategy to direct packets to their destinations. Then the researchers analyzed each node to see how often it lies along the shortest path between two other nodes. For instance, if the shortest path between nodes A and B passes through node C, then C would be between A and B, increasing C’s value of a quantity called “betweenness.” Because nodes with large betweenness values are part of a greater number of shortest paths than peripheral nodes, they become congested more easily. To decrease this congestion, the researchers removed a fraction of the links connecting two nodes with some of the highest betweenness values. As a result, packets had to detour around these hub nodes, taking a slightly longer path but easing congestion in the most congestion-prone areas. Explore further Partial map of the Internet based on data from 2005. Links connect nodes that represent IP addresses. Image credit: Wikimedia Commons, CC BY 2.5 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: Zhang GuoQing and Cheng SuQi. “Enhancing network capacity effects of edge-removal in small-world networks.” Scientia Sinica Informationis 2012, 42(2) 151-160 DOI: 10.1360/112011-421Guo-Qing Zhang, Di Wang,Guo-Jie Li. “Enhancing the transmission efficiency by edge deletion in scale-free networks.” Physical Review E, 76, 017101 (2007). DOI: 10.1103/PhysRevE.76.017101 (PhysOrg.com) — Whether dealing with Internet traffic or vehicle traffic, congestion can slow everything down. One team of researchers working on improving network transmission efficiency has developed a strategy that identifies certain links or edges that can be removed to decrease the overall congestion. Somewhat counterintuitively, these links – which the researchers call “black sheep” – are those that connect the busiest hubs. In a sense, the strategy is similar to closing some of the busiest roads during rush hour, and finding that vehicles reach their destinations faster than before.
Explore further © 2013 Phys.org More information: www.bareconductive.com/ Nontoxic and drying at room temperature, the product has caught on with educators, DIY makers and inventors. They have a number of products on sale, and Radio Shack stocks their paint pen.. Paper as a vehicle for delivering more information than immediately meets the eye via the painted object—that is what they see as their opportunity. Applications for their paint can easily translate into talking billboards and walls, where objects on surfaces turn interactive. A light switch painted on paper, when touched, can turn on a light, or a touch on a poster object can make a sound. Wanting to expand in recognition, they hope to appeal to a wide creative gamut of hobbyists, artists, and engineers for innovative ways to use their products. Bare Paint, they emphasized, is the first non-toxic electrically conductive paint available. As such the substance is child friendly, which opens the door to educational projects, including toys, and touch-sensitive paper drawings that play sounds. “We generally split applications into two simple classifications, signaling and powering,” they said. “Signaling could include using the Paint as a potentiometer while interfacing with a micro-controller, as a conduit in a larger circuit or as a capacitive sensor. Powering a device would include lighting LED’s or driving small speakers. The most interesting stuff happens when you combine these properties into something new.”According to the company, Bare Paint has a surface resistivity of approximately 55 ohms/square at 50 microns layer thickness. The product is water-based but it is not waterproof. One can paint over it with a waterproof paint or varnish, they said, depending on the application. The paint is only available in black, but it can be over-painted with any material with a wide range of other paints. London-based Bare Conductive Ltd. makes electrically conductive paint called Bare Paint. The substance allows the painting of “liquid wiring” on any surface. Except for skin, you can apply its paint on walls and assorted surfaces to conduct electricity. “Bare Paint” began as a project by the inventors, then students, at the Royal College of Art. Despite all the jokes about Wikipedia as a questionable knowledge crutch, the inventors credit Wikipedia as having helped them to learn what they had to know about working with conductive materials to get something going. In 2011 the RCA graduates were able to introduce Bare Paint. 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: Conductive paint lands in pens and pots for creatives (2013, May 26) retrieved 18 August 2019 from https://phys.org/news/2013-05-pens-pots-creatives.html Honda develops ‘Honda smart ecological paint,’ highly functional painting technology
The wearable battery is embedded in the sweatshirt and in a watch strap. The battery in the watch strap is shown powering 6 LEDs. Both batteries are made of unconventional battery materials that are highly suitable for flexibility. Credit: Yong-Hee Lee, et al. “The greatest significance of our work is that the wearing capability of lithium ion batteries becomes facilitated by building the battery assemblies from the same material as the mother clothes, textile,” Choi told Phys.org. “Reshaping the battery system by engaging the materials of the target applications to which the batteries are attached is a key idea in the current work.”Together, these materials create a battery that has both a high performance and excellent flexibility. Performance-wise, the nickel coating gives the battery a very small resistance that is several orders of magnitude smaller than that of carbon nanomaterials, and similar to that of the aluminum used in conventional (inflexible) batteries. 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. NJIT researchers invent flexible battery made from carbon nanotubes Journal information: Nano Letters © 2013 Phys.org. All rights reserved. Explore further Now in a new study, researchers have completely overhauled the key components of a typical battery by using new materials that provide superior performance under extreme folding conditions compared to flexible rechargeable batteries made from carbon nanomaterials. Ultimately, such a textile battery could be either attached onto clothes or embedded between the woven layers of the clothing fabric. It would supply the power for wearable electronic devices that fulfill the functions of today’s smart phones, from watching videos to taking photos to using social media.The researchers, led by Taek-Soo Kim, Jung-Yong Lee, and Jang Wook Choi at the KAIST Institute NanoCentury at the Korea Advanced Institute of Science and Technology (KAIST) in Daejeon, South Korea, have published their paper on the new wearable battery in a recent issue of Nano Letters.Just as the limiting factor of flexible electronics is the battery, the limiting factors of the flexible batteries are the electrodes, current collector, and other key battery components that are traditionally made of rigid materials. Instead of using carbon nanomaterials for these key components, the researchers here investigated a wide range of unconventional battery material candidates. They ultimately settled on using polyester yarn as the textile substrate, which they coated with nickel as the current collector. The nickel coating was then coated with polyurethane to form the electrodes, along with the binder and separator, which support the electrodes. (Phys.org) —While there has been much research lately on the development of flexible electronic devices that can be integrated into clothes, glasses, watches, and even skin, the limiting factor of this technology is the battery. Although flexible batteries made of carbon nanotubes and graphene have recently been developed, they still face hurdles due to their high resistance and scalability issues. The researchers demonstrated the battery’s good performance under folding conditions by building a home-made folding instrument that folds the battery every 1.5 cm at a tightly compressed folding radius of 0.65 mm—a degree of folding that is more extreme than that used to test most other textile batteries. Nevertheless, the new battery shows that, after 5500 deep folding-unfolding cycles, it retains 91.8% of its original capacity. (The capacity of this battery is 13 mAh, but can be improved to 85 mAh using a different method of weaving the polyester yarn, and the researchers expect further improvements in the future.)In addition to these attractive properties, the researchers also demonstrated that flexible polymer solar cells can be integrated into the textile battery and used to recharge the battery while it’s being worn, eliminating the need to wire the battery (and your shirt or watch, etc.) to a power outlet each time it needs to be recharged. The researchers write that the solar charging system is decent, and demonstrate that a fully solar-charged textile battery can light up nine LEDs, each of which has a power consumption of 0.042 W.Overall, the new textile battery shows that the energy storage component of wearable electronics is catching up with other the components, bringing wearable electronics a step closer to reality.”We need further tuning of battery properties in several aspects (energy density, operating voltage, etc.) depending on target applications,” Choi said. “Communication with industry dealing with end applications is currently going along this direction.” Citation: Ultra-flexible battery’s performance rises to meet demands of wearable electronics (2013, November 18) retrieved 18 August 2019 from https://phys.org/news/2013-11-ultra-flexible-battery-demands-wearable-electronics.html More information: Yong-Hee Lee, et al. “Wearable Textile Battery Rechargeable by Solar Energy.” Nano Letters. DOI: 10.1021/nl403860k Flexible solar cells can be integrated into the textile battery and used to recharge the battery while it’s being worn, eliminating the need to wire the battery to a power outlet. Credit: Yong-Hee Lee, et al.
Explore further Precision breeding needed to adapt corn to climate change (Phys.org)—An international team of researchers has found evidence showing that maize evolved to survive in the U.S. southwest highlands thousands of years ago. In their paper published in the journal Science, the group outlines their genomic study, which revealed the genetic changes that allowed the plant to live in the harsher environment. Maize diversity from the Native Seeds/SEARCH collection. Credit: Native Seeds/SEARCH © 2017 Phys.org Unit where maize was recovered at Turkey Pen with side columns excavated. Credit: R.G. Matson Citation: Genome sequencing shows maize adapted to highlands thousands of years ago (2017, August 4) retrieved 18 August 2019 from https://phys.org/news/2017-08-genome-sequencing-maize-highlands-thousands.html The researchers suggest that learning more about how maize evolved to survive in the colder highlands offers insights as climate change forces many crop plants to do the same to survive in new conditions. They also noted that one type of maize high in carotenoids, which is now used to make popcorn, evolved in the southwest part of what is now the U.S. and not in Mexico. More information: Kelly Swarts et al. Genomic estimation of complex traits reveals ancient maize adaptation to temperate North America, Science (2017). DOI: 10.1126/science.aam9425AbstractBy 4000 years ago, people had introduced maize to the southwestern United States; full agriculture was established quickly in the lowland deserts but delayed in the temperate highlands for 2000 years. We test if the earliest upland maize was adapted for early flowering, a characteristic of modern temperate maize. We sequenced fifteen 1900-year-old maize cobs from Turkey Pen Shelter in the temperate Southwest. Indirectly validated genomic models predicted that Turkey Pen maize was marginally adapted with respect to flowering, as well as short, tillering, and segregating for yellow kernel color. Temperate adaptation drove modern population differentiation and was selected in situ from ancient standing variation. Validated prediction of polygenic traits improves our understanding of ancient phenotypes and the dynamics of environmental adaptation. Journal information: Science Sampled cobs from Turkey Pen Shelter. Credit: Bruce Benz Maize, more commonly known as corn, originated in Mexico and made its way to what is now the southwestern U.S. approximately 4,000 years ago. In doing so, it quickly became one of the most important crops in the North America. But, as the researchers note, it did not make its way into the highlands for another 2,000 years, a development that has puzzled archaeologists. To better understand why the delay occurred, the researchers studied samples of 2,000-year-old maize cobs found in a cave back in the 1970s in Utah’s highlands. To learn more about its physical attributes, they sequenced the genome of 15 of the cobs and compared the results to other maize lines. They report that the maize plants around the cave area were not as tall as other maize plants that grew at lower elevations and that it had more branches—in short, they describe the plants as more bushy than other maize plants, a trait that allowed the plant to thrive in colder places. They also found evidence that the plant flowered earlier than most other maize plants, an attribute that would help it produce seeds before the earlier frost at higher elevations.As the plants evolved to withstand the harsher environment, early people living there began to introduce maize into their diet, just as other early people had done in the southwest lowlands thousands of years earlier. 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.
Darjeeling: ‘A well lit building. Suddenly a figure draped in white, with long flowing black hair appears and effortlessly climbs the pillars to disappear behind the balcony of the floor above…’ What could be a clip from any horror film is now doing the rounds on social media, with a person claiming to have clicked it in the middle of the night at the Darjeeling Sub-Divisional Hospital. The video, which has gone viral, has created quite an uproar in the Hill town. Also Read – Heavy rain hits traffic, flightsThe video, which had appeared on social media a few days ago, is accompanied by an audio clip, in which a male voice appeals to carefully watch the video that follows. He then goes on to claim that he had shot the clip at the Darjeeling Sadar Hospital.”This video clip was recorded by me in the out-patient department area of the Eden Hospital (Darjeeling Sadar Hospital). My aunt, who is terminally ill and admitted in bed number 135, wanted hot water and I had gone out to get it at around 11:40 pm when I saw this and recorded it,” stated the voice. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe clip soon became viral with questions being raised. “It is in no way the Sadar Hospital. We do not have such pillars. It is a prank and we are not giving much attention to this. However, the police and district administration should take action against any person or persons involved in such a prank,” stated Dr Saikat Pradhan, Superintendent of Darjeeling Sadar Hospital.Interestingly, the same video clip had earlier surfaced on social media in Bharuch, Gujarat.
Kolkata: The Kolkata Municipal Corporation (KMC) is mulling the idea of commencing a pilot project in Park Street area, for putting all overhead wires underground.Mayor Sovan Chatterjee said on Wednesday that a meeting in this regard has already been held in presence of state Urban Development and Municipal Affairs minister Firhad Hakim and a number of agencies like cable service MSOs, CESC, BSNL and similar stakeholders, whose wires, hanging from lampposts, trees and every vantage point, is an eyesore in the city’s skyline. Also Read – Heavy rain hits traffic, flights”The state government is seriously trying to work out a strategy on how to clear this ‘jungle of wires’. Chief Minister Mamata Banerjee has formed a high level committee in this regard, that comprises ministers like Firhad Hakim, Chandrima Bhattacharya, Moloy Ghatak and me. Kolkata is not a planned city like New Town, Rajarhat or Nabadiganta area in Salt Lake. So, the process will take time,” Chatterjee said.Responding to a poser from CPI(M) councillor Madhuchhanda Deb at the monthly meeting of the civic body, the Mayor pointed out that the paucity of road space in the city is a major hurdle in putting the overhead wires underground. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killed”There are a number of such overhead wires belonging to utility services, which have gone defunct. Locating the operational ones among them is a difficult job. Putting such overhead wires underground throughout the city will not be possible. Hence, we are working out a strategy,” Chatterjee maintained.Chief Minister Mamata Banerjee, while addressing multi-service operators (MSOs) and cable operators in April, had asked them to clean up the mess of wires and urged all stakeholders, including Kolkata Municipal Corporation (KMC), Public Works Department (PWD) and private utility CESC, whose posts are used to string up the cables, to chalk out a concrete plan that would set the house in order. It may be mentioned that the city has around 2,500 cable operators and 17 lakh cable homes, where the cables are connected. A conservative estimate puts the length of cables dangling all over the city at 20,000 km.In New Town, all cables have been underground since the inception. Pipes have been laid on both sides of the road at a depth of about 1 metre, to carry optic fibre cables or satellite TV cables. There are junction points every 20 metre or so, for connections to reach individual plots.
Filmmaker R Balki has revealed his upcoming movie, which has Arjun Kapoor and Kareena Kapoor Khan in the lead, will have a ‘very special appearance’ by megastar Amitabh Bachchan.The yet untitled film will see Arjun teaming up with the Bajrangi Bhaijaan actor for the first time. “I will start shooting my next with Kareena and Arjun soon. It has Mr Bachchan in it. He is doing a very special appearance in the film. Without his appearance the film will not be possible,” Balki told a media person.The director, who is an ardent Bachchan fan, has worked with the actor in all the films including Cheeni Kum, Paa and his latest Shamitabh, which failed to create a buzz.