Could Graphene Replace Semiconductors

first_img Citation: Could Graphene Replace Semiconductors? (2008, September 8) retrieved 18 August 2019 from https://phys.org/news/2008-09-graphene-semiconductors.html (PhysOrg.com) — “People want a faster computer chip,” Philip Kim tells PhysOrg.com. “And it needs to be smaller. But in order to increase the speed of the chip, or to get it smaller, we are approaching a point where you need materials other than silicon.” Researchers ‘iron out’ graphene’s wrinkles Kim, professor at Columbia University, believes that graphene may be just that material. Along with his colleagues, Bolotin, Sikes, Hone and Stormer, Kim thinks that suspended graphene may provide the transport capability needed to reach greater speeds in computer ships. The work of the group from Columbia University can be found in Physical Review Letters: “Temperature-Dependent Transport in Suspended Graphene.”When one looks at the structure of graphite, stacked layers of pure carbon are apparent. However, it wasn’t until 2004 that a process sophisticated enough to “slice” off one of the layers was discovered. This single layer is called graphene. Graphene is basically a sheet of bonded carbon atoms, with the thickness of only one atom. If one could look down at graphene from the top, one would observe that the sheet bears a strong resemblance to honeycomb, with its hexagons fitted snugly together.“Graphene behaves almost like semiconductor but without a energy gap,” Kim explains. This is why it would do well as a material for computer chips. “When you apply an electric field perpendicular to graphene, the number of electrons – the carrier density – can be tuned.”“One of the main themes is how fast the charge can move in graphene,” Kim continues. “Higher mobility means electron conducts faster in the system. It has always been speculated that the mobility of graphene can be quite high. But it has not been shown as high as some of the highest semiconductors in the past.”The group at Columbia University, however, has shown that graphene can exceed the transport speed of even the semiconductors with the highest mobility. They have done this by suspending the graphene at room temperature. “We have found that this transport ability is higher in the graphene than in any known semiconductor at room temperature.”“Lower mobility in graphene comes from external impurities, rather than intrinsic limitations,” Kim explains. “So the question becomes how to remove these impurities. Many of the impurities actually come from the substrate; this is the substance the graphene is sitting on. Suspending the graphene and subsequently annealing it would help ‘clean’ the graphene, and increase the mobility.”The current work also shows that temperature plays a role in the transport ability of graphene. “We found that the graphene has the highest mobility at room temperature,” Kim says. “This is great, since various applications would get more use out of something that can work in the real world.”And the future? Kim believes that there are still impurities in the graphene. “There are still limits right now,” he says. “I think we can bring the mobility even higher.”Kim maintains that this discovery of temperature-dependent transport in graphene goes beyond practical application. “Every time you discover something like this – where mobility is really enhanced – it results in a discovery of new physics. I think the same thing will happen with graphene. Improving mobility will allow us to look at new physics in a very exotic system.”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.center_img 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

Academic group says its time for researches to begin sharing source code

first_img Explore further Symantec urges users to disable pcAnywhere The group argues that because computer programs are now an integral part of research in almost every scientific field, it has become critical that researchers provide the source code for custom written applications in order for work to be peer reviewed or duplicated by other researchers attempting to verify results.Not providing source code, they say, is now akin to withholding parts of the procedural process, which results in a “black box” approach to science, which is of course, not tolerated in virtually every other area of research in which results are published. It’s difficult to imagine any other realm of scientific research getting such a pass and the fact that code is not published in an open source forum detracts from the credibility of any study upon which it is based. Articles based on computer simulations, for example, such as many of those written about astrophysics or environmental predictions, tend to become meaningless when they are offered without also offering the source code of the simulations on which they are based.The team acknowledges that many researchers are clearly reticent to reveal code that they feel is amateurish due to computer programming not being their profession and that some code may have commercial value, but suggest that such reasons should no longer be considered sufficient for withholding such code. They suggest that forcing researchers to reveal their code would likely result in cleaner more portable code and that open-source licensing could be made available for proprietary code. They also point out that many researchers use public funds to conduct their research and suggest that entities that provide such funds should require that source code created as part of any research effort be made public, as is the case with other resource materials.The group also points out that the use of computer code, both off the shelf and custom written will likely become ever more present in research endeavors, and thus as time passes, it becomes ever more crucial that such code is made available when results are published, otherwise, the very nature of peer review and reproducibility will cease to have meaning in the scientific context. Citation: Academic group says it’s time for researches to begin sharing source code (2012, April 16) retrieved 18 August 2019 from https://phys.org/news/2012-04-academic-group-source-code.html More information: Shining Light into Black Boxes, Science 13 April 2012: Vol. 336 no. 6078 pp. 159-160 DOI: 10.1126/science.1218263AbstractThe publication and open exchange of knowledge and material form the backbone of scientific progress and reproducibility and are obligatory for publicly funded research. Despite increasing reliance on computing in every domain of scientific endeavor, the computer source code critical to understanding and evaluating computer programs is commonly withheld, effectively rendering these programs “black boxes” in the research work flow. Exempting from basic publication and disclosure standards such a ubiquitous category of research tool carries substantial negative consequences. Eliminating this disparity will require concerted policy action by funding agencies and journal publishers, as well as changes in the way research institutions receiving public funds manage their intellectual property (IP). Journal information: Science © 2012 Phys.Org (Phys.org) — A diverse group of academic research scientists from across the U.S. have written a policy paper which has been published in the journal Science, suggesting that the time has come for all science journals to begin requiring computer source code be made available as a condition of publication. Currently, they say, only three of the top twenty journals do so. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Jurassic insect that mimicked ginkgo leaves discovered

first_img Explore further More information: Jurassic mimicry between a hangingfly and a ginkgo from China, PNAS, Published online before print November 26, 2012, doi: 10.1073/pnas.1205517109AbstractA near-perfect mimetic association between a mecopteran insect species and a ginkgoalean plant species from the late Middle Jurassic of northeastern China recently has been discovered. The association stems from a case of mixed identity between a particular plant and an insect in the laboratory and the field. This confusion is explained as a case of leaf mimesis, wherein the appearance of the multilobed leaf of Yimaia capituliformis (the ginkgoalean model) was accurately replicated by the wings and abdomen of the cimbrophlebiid Juracimbrophlebia ginkgofolia (the hangingfly mimic). Our results suggest that hangingflies developed leaf mimesis either as an antipredator avoidance device or possibly as a predatory strategy to provide an antiherbivore function for its plant hosts, thus gaining mutual benefit for both the hangingfly and the ginkgo species. This documentation of mimesis is a rare occasion whereby exquisitely preserved, co-occurring fossils occupy a narrow spatiotemporal window that reveal likely reciprocal mechanisms which plants and insects provide mutual defensive support during their preangiospermous evolutionary histories. The inch and a half long fossil specimen was first overlooked, the team says, as those that found it first believed it to be a (now extinct) five lobed ginkgo leaf sample embedded within ancient rock. Upon closer inspection, the researchers discovered that the specimen was actually that of a fossilized scorpionfly, which is known more commonly as a hangingfly (Juracimbrophlebia ginkgofolia), because of its tendency to hang from branches waiting for prey to pass by. It was found in the northeastern part of Inner Mongolia. The scorpionfly gets its name from its oversized male genitalia that resemble a scorpion stinger. To mimic surrounding ginkgo leaves, the insect would latch onto a branch, hang down and spread its wings wide open. The researchers suggest that the insect likely evolved its mimicry abilities to help it evade predators or to help it hide from prey, as is seen with many modern insects. The first attribute would have been most useful as close inspection of the insect revealed weak wings and legs. They noted also that it was possible that the insect and the ginkgo formed a partnership of sorts with the tree providing shelter and the hangingfly eating other bugs that might seek to feed on the trees’ leaves.The discovery of the hangingfly fossil adds to the knowledgebase of insects that mimic non-flowering plants. Most mimicking insects going back 100 million years tend to mimic angiosperms. The newly discovered hangingfly fossil predates other fossilized mimicking insects by approximately 40 million years.Both the fossilized hangingfly and the ginkgo plant that it mimicked, date back to the heyday of the dinosaurs and thus it’s quite possible that the plant served as food for them and other large herbivores. © 2012 Phys.org Journal information: Proceedings of the National Academy of Sciences Molecular study could push back angiosperm originscenter_img Camera lucida drawings of J. ginkgofolia gen. et sp. nov., holotype CNU-MEC-NN-2010–050P. Credit: (c)2012 PNAS, doi: 10.1073/pnas.1205517109 Citation: Jurassic insect that mimicked ginkgo leaves discovered (2012, November 28) retrieved 18 August 2019 from https://phys.org/news/2012-11-jurassic-insect-mimicked-ginkgo.html (Phys.org)—Researchers working in China have discovered an insect that lived 165 million years ago that they believe used its wings to mimic the leaves of an ancient ginkgo tree. The fossil finding, the team writes in their paper published in the Proceedings of the National Academy of Sciences, is one of the few that shows that early insects mimicked non-flowering plants millions of years before doing so with angiosperms. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Study shows capuchins less receptive to others who refuse to help when

first_img(Phys.org) —A team of Japanese and British researchers has found that capuchin monkeys behave less receptively towards people they observe who refuse to help when asked by another person. In their paper published in Nature Communications describing their study and findings, the group reports that the monkeys were less inclined to accept a treat from someone that wasn’t cooperative. Explore further More information: Third-party social evaluation of humans by monkeys, Nature Communications 4, Article number: 1561 doi:10.1038/ncomms2495AbstractHumans routinely socially evaluate others not only following direct interactions with them but also based on others’ interactions with third parties. In other species, ‘eavesdropping’ on third-party interactions is often used to gain information about foraging or mating opportunities, or others individuals’ aggressiveness or fighting ability. However, image scoring for potential cooperativeness is less well studied. Here we ask whether a non-human primate species, tufted capuchin monkeys (Cebus apella), socially evaluates humans after witnessing third-party interactions involving a helpful intervention or failure to help. We find that the monkeys accept food less frequently from those who persistently reject another’s requests for help. This negative social evaluation effect is robust across conditions, and tightly linked to explicit refusal to help. Evaluation of potential helpfulness based on third-party interactions may thus not be unique to humans.Press release: phys.org/news/2013-03-selfish-grinder-monkey.html The researchers note that previous research has shown that capuchin monkeys are social by nature. They share resources and cooperate with one another to achieve goals. To find out more about how the primates relate to one another or those of another species, the team set up an experiment to see if the monkeys might harbor ill-will towards those that are not inclined to help someone else out when asked.Two volunteer actors were placed in front of a monkey so that their interaction could be seen. One of the actors held a jar that contained objects unknown to the monkey. He or she simulated attempting to open the jar but failed, indicating the lid was too tight. He or she then asked the second actor to help open the jar. In some scenarios, the second actor agreed and helped out, in others, he or she refused to help at all. After each little skit, both actors held out a food treat for the monkey, only one of which the monkey could accept. The researchers found that the monkey preferred to accept the treat from the actor that held the jar over an actor that refused to help. When presented with treats when the actor did help open the jar, the monkey demonstrated no preference on treat acceptance. To make sure other variables weren’t at play, the researchers repeated the experiment many times with different monkeys, actors and genders. They also ran trials where the actor who was asked to help refused because he or she was busy trying to open their own jar. In such cases, the observing monkeys appeared to give the actor who refused to help a pass.The results of the experiment indicate that the monkeys are not only able to understand what is occurring in such interactions, but are impacted by what they see. It also indicates a degree of understanding of motive and cause and effect. More work will have to be done to gain a deeper perspective however, as it appears possible that the monkeys were simply more open to whichever actor appeared to be more in control of the situation. © 2013 Phys.org Sort out the selfish organ grinder, not the monkey!center_img Journal information: Nature Communications Human interactions observed by monkeys. Credit: Nature Communications , doi:10.1038/ncomms2495 Citation: Study shows capuchins less receptive to others who refuse to help when asked (2013, March 6) retrieved 18 August 2019 from https://phys.org/news/2013-03-capuchins-receptive.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.last_img read more

Best of Last Week Acoustic phonons have magnetic properties universe to collapse

first_img © 2015 Phys.org In space news, a team of researchers at the University of Nottingham announced that the universe may be on the brink of collapse—in cosmological terms, of course. Meanwhile, another team suggested that a wandering Jupiter may account for our unusual solar system. They believe the planets’ early inward-outward migration might have impacted the way the other planets developed. Also new research suggests Europa’s elusive water plume paints a grim picture for life—that plume spotted two years ago appears to have been caused by a meteorite impact, rather than an emission from the surface, dashing hopes that it might have been a good indicator of life on one of Jupiter’s largest moons.In other news a team of mathematicians has solved a 60-year-old problem—a neat explanation for the Fermi-Pasta-Ulam problem. Also a team of researchers has found that using high-definition scans can reveal the effects of pregnant mothers’ smoking on unborn babies—in their facial expressions, no less. And a team at Harvard announced that they had taken another step in bringing back a wooly mammoth—they are not trying to clone it, instead they are replicating parts of its DNA.And finally, if you have been worried that stress induced insomnia might be hurting your brain, a team of researchers has found that a disrupted biological clock has a link to Alzheimer’s disease—so, you may be right and now you have something else to worry about. Landmark study proves that magnets can control heat and sound Explore further It was another good week for physics as researchers at Ohio State University conducted a landmark study that proved that magnets can control heat and sound—they demonstrated a magnetic field reducing the amount of heat flowing through a semiconductor, proving that acoustic phonons have magnetic properties. In another study, a combined team of researchers from the University of Belgrade and MIT revealed a technique they had developed that allowed for entangling 3,000 atoms using a single photon, representing a new milestone in the number of particles that have been entangled at one time. Also a team of researchers at Griffith University ran an experiment that demonstrated entanglement of a single particle—showing that the collapse of the wave is a real effect.center_img Researchers at The Ohio State University have discovered that heat can be controlled with a magnetic field. Here, study leader Joseph Heremans, Ohio Eminent Scholar in Nanotechnology, holds the material used in the experiment: a piece of indium antimonide semiconductor shaped into a lopsided tuning fork. The wider arm of the fork (left) measures 4 mm wide, and the narrower one (right) measures 1 mm. The researchers were able to slow the movement of heat through the wider arm of the fork using a magnetic field. Credit: Photo by Kevin Fitzsimons, courtesy of The Ohio State University. Citation: Best of Last Week: Acoustic phonons have magnetic properties, universe to collapse and bioclock disruption problem (2015, March 30) retrieved 18 August 2019 from https://phys.org/news/2015-03-week-acoustic-phonons-magnetic-properties.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.last_img read more

Study shows the difference between classical flows and superfluid helium in 3D

first_imgResearchers at the Weizmann Institute of Science, the University of Rome, CNRS and the University of Helsinki have recently carried out a study investigating the difference between 3-D anisotropic turbulence in classical fluids and that in superfluids, such as helium. Their findings, published in Physical Review Letters (PRL), are supported by both theory and experimental evidence. Mathematician makes breakthrough in understanding of turbulence Explore further Citation: Study shows the difference between classical flows and superfluid helium in 3-D counter-flow (2019, April 22) retrieved 18 August 2019 from https://phys.org/news/2019-04-difference-classical-superfluid-helium-d.html More information: L. Biferale et al. Superfluid Helium in Three-Dimensional Counterflow Differs Strongly from Classical Flows: Anisotropy on Small Scales, Physical Review Letters (2019). DOI: 10.1103/PhysRevLett.122.144501 Credit: Biferale et al.center_img “The present research was initiated by our group at the Weizmann Institute, Israel, comprised by Victor L’vov, Itamar Procaccia and Anna Pomyalov, who were trying to understand novel experimental observations by the groups of Prof. Wei Guo from Florida State University, Tallahassee and Prof. Ladislav Skrbek from Charles University, in Prague,” Itamar Procaccia, one of the researchers who carried out the study, told Phys.org. “Our main objective was to understand an apparent surprising difference in how energy distributes between turbulent eddies of different scales in classical viscous fluids like air and water and superfluids like helium at low temperatures.”All turbulent flows, both in nature and laboratory settings, are anisotropic on energy injection scales, meaning that energy distributes differently between their turbulent eddies. Past studies have shown that the model of homogeneous and isotropic turbulence (HIT) is particularly effective for predicting the statistical properties of turbulence on scales much smaller than stirring scales, yet larger than dissipative scales. In classical fluids, 3-D anisotropic turbulence tends towards isotropy and homogeneity with decreasing scales, hence it is eventually possible to apply the HIT model to them. In their study, however, Procaccia and his colleagues demonstrated that the opposite is true for superfluid 4He turbulence in 3-D counter-flow channel geometry, which becomes less isotropic as scales decrease, to the point of becoming almost two-dimensional. The approach used by them involves a so-called ‘two-fluid model’ of superfluid helium. This model is based on the early work of Laszlo Tisza and Lev Landau back in 1940-1941, which was later improved by H. Hall, W.F. Vinen, I.M. Khalatnikov, and I.L Bekarevich. “The model describes superfluid helium as an interpenetrating mixture of two fluids: a superfluid that moves without friction, and a normal viscous fluid that are coupled by a mutual friction,” Procaccia explained. Past studies carried out by two teams of researchers in Tallahasse, Florida and Prague examined superfluid helium under a temperature gradient, creating what is referred to as ‘counter-flow’. As suggested by its name, in counter-flow different components of a fluid flow in opposite directions; the superfluid flows from the cold to the hot side and the normal fluid from the hot to the cold side. “Our model rationalized some of these experimental observations and predicted new features that were later confirmed experimentally,” Procaccia explained. “The main result of our study is that contrary to classical turbulent flows which become more and more isotropic at smaller scales, the flow we examined becomes less and less isotropic as the scales reduce.” Before they carried out their study, Procaccia and his colleagues had theoretically predicted that their experiments would lead to the observations that they subsequently collected. However, the strength of the effect they observed only became clear after they carried out direct numerical simulations on a EU supercomputer, in collaboration with a team of researchers led by Luca Biferale. According to Procaccia, their theoretical and numerical findings have already motivated other experimental groups to pursue further research into counter-flow turbulence. “At the Weizmann Institute, we are now developing our theory further, being attentive to the new experimental techniques that enable elaborate studies of turbulence in superfluid helium,” Procaccia said. “Our group continues to participate in the analysis of new experimental data, hoping to contribute to deeper understanding of superfluid flows from laboratory experiments to cosmological realization, such as neutron stars.” © 2019 Science X Network Journal information: Physical Review Letters This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.last_img read more

Jazz it up

first_imgFor the fourth time again International Jazz Festival in association with the ICCR, this year the color theme is ‘Blue’ which portrays universal symbol for youth and it’s the least gender specific color, having equal appeal for all. It also decreases psychological effects and creates wisdom, royalty and strength.This event will feature world famous international artistes as well as the best local talent from different parts of India. The stars of the event are – Ari Roland Quartet known better as the Golden Age of Jazz; Ximo Tebar, the Spanish musician who has won the most awards in the last few years, PJ Perry who at the age of 72 is one of North America’s premier saxophonists; Tres Butacas meaning ‘three seats’ – a beautiful proposal Colombian music mixed with Jazz, Brazilian, bolero and pop and more.The three-day event will feature performances from a power house line up of musicians and bands including Ari Roland Quartet (USA), Smarton Trio (Hungary), Black Slade Jazz Rock (India), Tres Butacas (Colombia), Obara Quartet (Poland), Mina Agossi Trio (France), The PJ Perry Trio (Canada), Ximo Tebar and IVAM Jazz Ensamble (Spain), Joe Alvares and Trident Jazz Trio (Mumbai) and lastly Modern Han (South Korea). Don’t miss this!last_img read more

North by North East

first_imgAfter a hugely successful inaugural last year, the second edition of the North East Festival kicked off in great style in a brand new avatar in the Capital. Being held from 7 to 10 November at IGNCA, Janpath, this year’s edition of the festival with the theme Insurgence to Resurgence is focusing  on the various business and investment opportunities that the region presents, apart from showcasing the multifarious culture and rich heritage of the North Eastern states. Also Read – ‘Playing Jojo was emotionally exhausting’North East Festival is organised by the reputed socio-cultural trust, Trend MMS, in association with North East Community of Delhi, Ministry of Home Affairs, Ministry of Department of North Eastern Region (DoNER) and Indira Gandhi National Centre for Arts (IGNCA). The chief guests at the inauguration of  the four day extravaganza were Union Minister Gen. VK Singh and minister of state (home) Kiren Rjiju along with MC Mary Kom, Brand Ambassador of the North East Festival. In the inaugural session, medal winning athletes from the North East who brought glory for the country in the recent CWG and Asian Games,  including names like Mary Kom, Sarita Devi, L. Devendro Singh, Dipa Karmakar were felicitated under NEC Chairman’s Sports Awards for Excellence in International and National Sports meets. Also Read – Leslie doing new comedy special with NetflixAdding colour to the proceedings, artistes from various states of North East India along with Sangeet Natak Akademi presented a range of ethnic dances from the region. Sumptuous cuisines  were in abundance in the various food stalls along with exquisite handicrafts and ethnic handlooms from the region. Various music bands like from NER like Guwahati Lights, Akhu – Imphal Talkies, Vinyl Record, Soulmate, The Local Train etc. performed all through the day much to the delight of the onlookers.During the morning session, a discussion was held on ‘Alienation feeling in the North East and Implementation of Bezbaruah Committee Recommendation’ with the help of North East Community of Delhi. The North East Festival, has become a brand which is synonymous with the unification of the various stakeholders of North East under one dynamic platform.last_img read more

Grooving to Aussie beats

first_imgProgressive rock music fans in India are in for a treat as Australian hard-rock band Karnivool began a three-city back to back tour, playing in Delhi, Chennai and Kolkata. They started their musical tour with the first Edition of Lockdown Festival in Gurgaon, on January 9, the band is set to perform at Saarang 2015, the cultural festival of Indian Institute of Technology Madras on January 10. The band will wrap up their whirlwind tour at The Festival in Kolkata on January 11. Also Read – ‘Playing Jojo was emotionally exhausting’Garnering appreciation from giant music magazines like Rolling Stone, Billboard Magazine, Kerrang! and Rocksound, Karnivool debuted with their acclaimed debut album Themata (2005), closely followed by ground breaking Sound Awake (2009). Their third album Asymmetry (2013), believed to be brazen and introspective belied expectation, establishing Karnivool as one of the most vital forces in progressive modern music.This album went straight to number one in the Australian charts, winning an ARIA three months later and achieving gold status. Also Read – Leslie doing new comedy special with NetflixThe band members- Ian Kenny on vocals, Drew Goddard and Mark Hosking on guitar, Jon Stockman on bass, and Steve Judd on drum have toured globally since the release and are very excited to be returning to India with their incredible, multiple award winning live show for a third time. The band has appeared at major festivals such as The Big Day Out (Australia), Sonisphere UK, France), Download (UK), SXSW (US) and Rock AM Ring/Rock Im Park (Germany). Karnivool had last toured India in 2012-13 as part of Oz Festival – the biggest Australian cultural festival ever staged in India. The tour, supported by the Australian Government was presented by Australia’s contemporary music export initiatives ‘Sounds Australia’ and ‘Stage Mothers’.last_img read more

HC green signals recruitment of upper primary teachers

first_imgKolkata: The Calcutta High Court on Monday gave the nod for recruitment of upper primary teachers in the government schools. The court’s direction has made it clear that out of a vacancy of 14,000 teachers, 12,600 teachers can now be recruited in classes V to VIII in the state schools. It has been mentioned that some teachers’ organisation had moved the high court, challenging the 2009 notification of School Service Commission (SSC) that had reserved 10 percent of the seats for para teachers. Justice Tapabrata Chakraborty, however, said that the 10 percent will be reserved for para teachers till the conclusion of the case. The next hearing has been scheduled in July. “Justice Chakraborty has said that 90 percent of the recruitment should not remain stalled for a deadlock of 10 percent para teachers,” said advocate Gourav Das, who appeared for the petitioners.last_img read more