Altered forests threaten sustainability of subsistence hunting

first_imgArticle published by John Cannon Agriculture, Animals, Biodiversity, Biodiversity Crisis, Biodiversity Hotspots, Birds, Bushmeat, Cloud Forests, Conservation, Deforestation, Ecology, Ecosystem Services, Ecosystem Services Payments, Ecosystems, Endangered Species, Environment, Extinction, Forest People, Forestry, Forests, Fragmentation, Human Migration, Human Rights, Human-wildlife Conflict, Hunting, Illegal Logging, In-situ Conservation, Indigenous Communities, Indigenous Cultures, Indigenous Groups, Indigenous Peoples, Indigenous Reserves, Indigenous Rights, Iucn, Land Conflict, Land Reform, Land Rights, Logging, Mammals, Mining, Natural Capital, Palm Oil, Parks, Payments For Ecosystem Services, Poaching, Pollution, Poverty, Poverty Alleviation, Primary Forests, Primates, Protected Areas, Pulp And Paper, Rainforest Agriculture, Rainforest Animals, Rainforest Biodiversity, Rainforest Conservation, Rainforest Destruction, Rainforest Ecological Services, Rainforest Logging, Rainforest Mining, Rainforest People, Rainforests, Research, Resource Curse, Roads, Saving Species From Extinction, Social Conflict, Social Justice, Sustainable Development, Sustainable Forest Management, Technology, Threats To Rainforests, Timber, Traditional People, Trees, Tribal Groups, Tropical Forests, Wcs, Wildlife, Wildlife Conservation, Wildlife Trade In a commentary, two conservation scientists say that changes to the forests of Central and South America may mean that subsistence hunting there is no longer sustainable.Habitat loss and commercial hunting have put increasing pressure on species, leading to the loss of both biodiversity and a critical source of protein for these communities.The authors suggest that allowing the hunting of only certain species, strengthening parks and reserves, and helping communities find alternative livelihoods and sources of food could help address the problem, though they acknowledge the difficult nature of these solutions. The way humans have changed the forests of Central and South America may be making it impossible for subsistence hunters to continue their way of life, according to two conservation scientists.“No longer can subsistence hunting be seen or managed as a sustainable activity carried out by small, isolated human groups occupying large tracts of natural habitat and using traditional hunting methods,” Galo Zapata‐Ríos, who directs the science program for the Wildlife Conservation Society’s (WCS) Ecuador program, said in a statement. “Any approach to the problem must take into account the fundamentally different context in which subsistence hunting occurs in the present day.”Scientists have generally thought that groups that rely on hunting to feed themselves and their families under these conditions — and as it has occurred for generations in some places — could do so without affecting the local survival of certain species.An armadillo taken by hunters. Image by Galo Zapata-Ríos/WCS.But Zapata‐Ríos and his colleague, Esteban Suárez, an ecologist and professor at Universidad San Francisco de Quito, say the widespread impacts humans have had in the “neotropical” forests of the Americas force a rethink of those assumptions.“Any approach to the problem must take into account the fundamentally different context in which subsistence hunting occurs in the present day,” the authors write in a commentary published May 8 in the journal Biotropica.Deforestation for timber and agriculture has carved through the region’s rainforests, leaving smaller and fewer fragmented refuges for species to inhabit. And an influx of people from outside, whether due to oil exploration, mineral extraction, or tourism, has helped fuel larger-scale hunting, sometimes even commercial-scale, they write.Add to that even low levels of subsistence hunting pressure, and the burden could be enough to wipe out some species. Not only does that diminish the biodiversity of the surroundings, but it also robs those very communities of a critical source of food, Zapata‐Ríos and Suárez say.A capybara in Colombia. Image by Rhett A. Butler/Mongabay.The researchers outline several potential remedies, but acknowledge that none are perfect solutions. Wildlife managers could allow subsistence hunting only of certain animals that are numerous or reproduce swiftly enough to cope with the pressure. Parks and reserves with stronger protections could also provide places where animals can escape hunting pressure and thus keep their numbers up.The pair’s research also looked at attempts to incentivize communities to switch to livestock rearing as a way to replace the protein in their diet that hunting historically provided, and, more drastically, projects to resettle subsistence hunters outside key areas that are home to rare or threatened species.One study they cite found that more than two-thirds of a community in India that had been moved from the Bhadra Wildlife Sanctuary “perceived that their quality of life had improved and were satisfied with the outcome of the relocation,” but that’s not always the case.A chestnut-eared aracari in Colombia. Image by Rhett A. Butler/Mongabay.“There is ample evidence showing that resettlement of human populations in the name of conservation can result in severe social, cultural, and economic impacts that often affect the most marginalized groups among societies,” the team writes.The researchers say that far-reaching initiatives are necessary if we’re to stem the loss of species from the bevy of threats they face. But they also point out the difficult situation that the outside world’s impacts on the region’s ecosystems have put communities of subsistence hunters in.“[W]e give them the tools and expectations of the Western World, and then, we hope that they can succeed at living sustainably, even if we have constantly failed,” the authors write.Banner image of a red howler monkey in Colombia by Rhett A. Butler/Mongabay.CitationsKaranth, K. K. (2007). Making resettlement work: The case of India’s Bhadra wildlife sanctuary. Biological Conservation, 139, 315–324. doi:10.1016/j.biocon.2007.07.004Suarez, E., & Zapata‐Ríos, G. Managing subsistence hunting in the changing landscape of Neotropical rain forests. Biotropica. doi:10.1111/btp.12662FEEDBACK: Use this form to send a message to the author of this post. If you want to post a public comment, you can do that at the bottom of the page.center_img Popular in the CommunitySponsoredSponsoredOrangutan found tortured and decapitated prompts Indonesia probeEMGIES17 Jan, 2018We will never know the full extent of what this poor Orangutan went through before he died, the same must be done to this evil perpetrator(s) they don’t deserve the air that they breathe this has truly upset me and I wonder for the future for these wonderful creatures. So called ‘Mankind’ has a lot to answer for we are the only ones ruining this world I prefer animals to humans any day of the week.What makes community ecotourism succeed? In Madagascar, location, location, locationScissors1dOther countries should also learn and try to incorporateWhy you should care about the current wave of mass extinctions (commentary)Processor1 DecAfter all, there is no infinite anything in the whole galaxy!Infinite stupidity, right here on earth.The wildlife trade threatens people and animals alike (commentary)Anchor3dUnfortunately I feel The Chinese have no compassion for any living animal. They are a cruel country that as we knowneatbeverything that moves and do not humanily kill these poor animals and insects. They have no health and safety on their markets and they then contract these diseases. Maybe its karma maybe they should look at the way they live and stop using animals for all there so called remedies. DisgustingConservationists welcome China’s wildlife trade banThobolo27 JanChina has consistently been the worlds worst, “ Face of Evil “ in regards our planets flora and fauna survival. In some ways, this is nature trying to fight back. This ban is great, but the rest of the world just cannot allow it to be temporary, because history has demonstrated that once this coronavirus passes, they will in all likelihood, simply revert to been the planets worst Ecco Terrorists. Let’s simply not allow this to happen! How and why they have been able to degrade this planets iconic species, rape the planets rivers, oceans and forests, with apparent impunity, is just mind boggling! Please no more.Probing rural poachers in Africa: Why do they poach?Carrot3dOne day I feel like animals will be more scarce, and I agree with one of my friends, they said that poaching will take over the world, but I also hope notUpset about Amazon fires last year? Focus on deforestation this year (commentary)Bullhorn4dLies and more leisSponsoredSponsoredCoke is again the biggest culprit behind plastic waste in the PhilippinesGrapes7 NovOnce again the article blames companies for the actions of individuals. It is individuals that buy these products, it is individuals that dispose of them improperly. If we want to change it, we have to change, not just create bad guys to blame.Brazilian response to Bolsonaro policies and Amazon fires growsCar4 SepThank you for this excellent report. I feel overwhelmed by the ecocidal intent of the Bolsonaro government in the name of ‘developing’ their ‘God-given’ resources.U.S. allocates first of $30M in grants for forest conservation in SumatraPlanet4dcarrot hella thick ;)Melting Arctic sea ice may be altering winds, weather at equator: studyleftylarry30 JanThe Arctic sea ice seems to be recovering this winter as per the last 10-12 years, good news.Malaysia has the world’s highest deforestation rate, reveals Google forest mapBone27 Sep, 2018Who you’re trying to fool with selective data revelation?You can’t hide the truth if you show historical deforestation for all countries, especially in Europe from 1800s to this day. WorldBank has a good wholesome data on this.Mass tree planting along India’s Cauvery River has scientists worriedSurendra Nekkanti23 JanHi Mongabay. Good effort trying to be objective in this article. I would like to give a constructive feedback which could help in clearing things up.1. It is mentioned that planting trees in village common lands will have negative affects socially and ecologically. There is no need to even have to agree or disagree with it, because, you also mentioned the fact that Cauvery Calling aims to plant trees only in the private lands of the farmers. So, plantation in the common lands doesn’t come into the picture.2.I don’t see that the ecologists are totally against this project, but just they they have some concerns, mainly in terms of what species of trees will be planted. And because there was no direct communication between the ecologists and Isha Foundation, it was not possible for them to address the concerns. As you seem to have spoken with an Isha spokesperson, if you could connect the concerned parties, it would be great, because I see that the ecologists are genuinely interested in making sure things are done the right way.May we all come together and make things happen.Rare Amazon bush dogs caught on camera in BoliviaCarrot1 Feba very good iniciative to be fallowed by the ranchers all overSponsoredlast_img read more

Reddit’s mobile apps now let people view only visual posts, block ads through in-app browser

first_img Posted on 19th December 2017Digital Marketing FacebookshareTwittertweetGoogle+share HomeDigital MarketingReddit’s mobile apps now let people view only visual posts, block ads through in-app browser In a redesign of its mobile apps announced on Monday, Reddit will add an option for people to only view non-text posts, which could help its fledgling video advertising business, and support for Apple’s Safari View Controller, which would enable people to block ads on publishers’ sites accessed through Reddit’s iOS app.The social network is also adding private messaging within its iOS app, which could pave a path to Reddit becoming a customer service channel for businesses in the same way that Twitter, Facebook’s Messenger and Facebook’s WhatsApp have or are trying to.Theater ModeReddit is commonly associated with text-laden posts and comments. But it’s also a hotbed for GIFs and meme photos. Now Reddit’s apps for Android and iOS will let people choose to see the only the visual side of Reddit through a new feature called “Theater Mode.”Reddit’s Theater Mode works similarly to the lightbox-style overlay that appears when tapping a post within Instagram’s Explore tab. When people tap on a post within Reddit’s app that contains a photo, video, GIF or other media element, that post will be enlarged and placed in a horizontal carousel of other visual posts from the corresponding feed or subreddit that people will be able to scroll through.For now, Reddit will not insert ads among the posts shown in Theater Mode, according to a Reddit spokesperson. But it’s easy to see how that could change and why Reddit would want to change it.Earlier this year, Reddit rolled out autoplay video ads to grab brand advertisers’ attention and ad dollars. Those video ads can easily stand out in a sea of text-based posts that may populate people’s feeds, but advertisers may prefer them to appear alongside other visual content because people in that context have signaled their intent in viewing visual content and may be more likely to be interested in the brand’s video ad. Additionally, displaying ads at full-screen, as with the other posts within Theater Mode’s feed as well as ads within Instagram’s and Snapchat’s Stories feeds, would boost the viewability of those ads and likely Reddit’s standing among advertisers that are increasingly mindful of whether their ads had a chance to be seen.Safari View Controller supportThe self-proclaimed “front page of the internet” also serves as a portal to other publishers’ sites through the links shared on Reddit. But now it may become harder for publishers to show ads to visitors coming from Reddit’s iOS app.Reddit is switching its iOS app’s in-app browser to Apple’s Safari View Controller. As a result — and as is also the case for Twitter’s iOS app — content blockers that people have installed on their iPhones and iPads to disable ads, tracking cookies, autoplay videos and other content from loading on sites opened within Safari will now work on links opened within Reddit’s app. People will also be able to switch to Safari’s Reader Mode when viewing webpages through Reddit’s app, which will similarly strip those pages of ads.As much as ad blocker support poses a con for publishers, Reddit’s adoption of Safari View Controller also comes with pros. Broadly speaking, it will make Reddit’s in-app browser function the same as Apple’s native Safari browser. That means people will be able to automatically fill out forms using AutoFill, making it easier for people to sign into publishers’ sites. And if someone is already signed in to a site on the native Safari app, that sign-in will persist in Reddit’s app, rather than forcing a person to sign in again to do something like view a page on a paywalled site.Private messagingReddit’s iOS app will now let people send private messages to their friends the way they would through Twitter, Facebook’s Messenger and a host of other app-based alternatives to traditional text messaging. And like those other messaging services, Reddit’s adoption of private messaging could enable businesses to use Reddit to handle customer service inquiries. However, Reddit will first need to prove that people are interested in using its in-app chat feature and then add tools to make it easy for businesses to manage and even automate their conversations.From our sponsors: Reddit’s mobile apps now let people view only visual posts, block ads through in-app browser Reddit’s mobile apps now let people view only visual posts, block ads through in-app browserYou are here: Related postsLytics now integrates with Google Marketing Platform to enable customer data-informed campaigns14th December 2019The California Consumer Privacy Act goes live in a few short weeks — Are you ready?14th December 2019ML 2019121313th December 2019Global email benchmark report finds email isn’t dead – it’s essential13th December 20192019 benchmark report: brand vs. non-brand traffic in Google Shopping12th December 2019Keep your LinkedIn advertising strategy focused in 202012th December 2019last_img read more

What Happens If Alabama Loses What If Every Favorite Wins We Have

At the core of the College Football Playoff is the assumption that four reasonably well-differentiated teams will be left standing at the end of the regular season and conference championship games, ready to be neatly penciled into a bracket.Unfortunately, such a tidy setup seldom actually happens in real life.This season is a good example. If you break things down into tiers of teams, at the top are three Tier 1 teams — undefeated major-conference squads plus independent Notre Dame1Because they are Notre Dame. — in Alabama, Clemson and the aforementioned Irish (two of which could potentially be conference champions as well). But there are also four Tier 2 teams — one-loss major-conference teams and undefeated minor-conference ones — in Ohio State, Oklahoma, Georgia and Central Florida. Even if you grant that poor UCF is likely to get little consideration (particularly with starting QB McKenzie Milton out with a leg injury), and that UGA would drop below Tier 2 with an SEC title-game loss to Bama, the math doesn’t quite work out to shield the selection committee from criticism. It still leaves too many deserving teams for too few slots.So with the help of our playoff odds algorithm, let’s run down the various permutations of what could happen on Championship Saturday to see who the model thinks would make the playoff in each.2Including every set of results that has at least a 2 percent probability of actually happening — with one special exception. Based on how the selection committee (and, before that, the BCS) has behaved in the past, we’ll break down how our system expects it to react this year. And we’ll go in order, from the least controversial to the most…(Note: These chances reflect the results from Week 13 but not the latest playoff committee rankings, which are released Tuesday night. Instead, they use our model’s expectation of how those rankings will change.)Alabama and Clemson win; Oklahoma OR Ohio State loses.Chances of happening: 23 percentLikely playoff field: Alabama (greater than 99 percent), Clemson (>99), OU or OSU winner (98), Notre Dame (94)Others: UCF (3 percent), Texas (2)This is one of the dream scenarios for the committee, as it would give them three top-tier teams and only two Tier 2 teams to choose from, one of which is non-Power 5 UCF with an injured QB. From there, picking the four playoff teams would be relatively straightforward.Alabama, Ohio State and Oklahoma win; Clemson loses.Chances of happening: 2 percentLikely playoff field: Alabama (>99 percent), Ohio State (94), Notre Dame (93), Oklahoma (92)Others: Clemson (11 percent)According to our model, this result would also benefit the selection committee. If Clemson were to lose the ACC title game to Pitt when favored by more than three touchdowns, the Tigers would suddenly be a Tier 2 team battling with a couple of fellow candidates (the Buckeyes and Sooners) who would each boast conference championships in this scenario.Clemson wins; Alabama and either Oklahoma OR Ohio State loses.Chances of happening: 14 percentLikely playoff field: Clemson (>99 percent), Georgia (99), Notre Dame (88), OU or OSU winner (83)Others: Alabama (24 percent)This is a variation of the first scenario listed above, where everything goes more or less to form except Georgia beats Alabama for the SEC title. I suspect our algorithm might be undercounting the chances that the committee stamps a playoff ticket for the Crimson Tide — who’ve had one of the most dominant seasons in college history — even with the loss. But taken on face value, a pair of conference champs (Oklahoma/Ohio State and UGA) might have a better case than a one-loss non-champ (Bama) within Tier 2.Clemson wins; Alabama, Oklahoma and Ohio State lose.Chances of happening: 3 percentLikely playoff field: Clemson (>99 percent), Georgia (>99), Notre Dame (98), Alabama (65)Others: Texas (16 percent), UCF (12), Washington (7)Despite the scary-sounding prospect of dealing with a one-loss, non-conference-champ Crimson Tide team, this sequence of events gets the committee off the hook to some extent. Clemson, Notre Dame and UGA would be easy calls, and it’s not hard to see Alabama rising over any of the other candidates for the No. 4 slot in the playoff field.Alabama, Clemson, Oklahoma AND Ohio State win.Chances of happening: 31 percentLikely playoff field: Alabama (>99 percent), Clemson (>99), Ohio State (69), Oklahoma (69)Others: Notre Dame (62 percent)Under this very plausible situation — the most likely on this list, in fact — the committee would have to make a tough choice among Ohio State, Oklahoma and Notre Dame for the third and fourth playoff seeds. Lacking any kind of special Notre Dame adjustment, the model thinks OSU and OU would come out ahead. Realistically speaking, however, it’s difficult to imagine that the committee would exclude an undefeated Irish squad, right or wrong. So that means it would come down to splitting hairs between the Buckeyes and Sooners. Good luck with that.Alabama and Clemson win; Oklahoma and Ohio State lose.Chances of happening: 4 percentLikely playoff field: Alabama (>99 percent), Clemson (>99), Notre Dame (98) and … ???Others: Texas (31 percent), Georgia (29), UCF (23), Washington (12), Ohio State (5)Most of the scenarios on this list involve too many good teams for too few slots. But in this particular case, there wouldn’t be enough. The committee would be staring at three clear-cut deserving squads, plus a whole bunch of flawed lower-tier teams in the mix for the fourth and final bid. Our model actually thinks three-loss (!) Texas would be the most likely candidate, though this is also one of UCF’s best, most viable paths to that elusive playoff berth.Clemson, Oklahoma and Ohio State win; Alabama loses.Chances of happening: 19 percentLikely playoff field: Clemson (>99 percent), Georgia (98), Ohio State (66), Oklahoma (62)Others: Notre Dame (60 percent), Alabama (13)This is the combination the selection committee has to be fearing the most, in part because it could happen so easily. It would simply require the Tigers, Sooners and Buckeyes winning a trio of games as favorites, and Georgia pulling off a not-unthinkable upset against the Tide for the SEC crown. Remember, the Bulldogs were in great shape for about a half in last year’s national championship game — before Bama stormed back to force overtime and eventually win. If UGA avenges that loss on Saturday, the committee would have a very tricky choice on its hands.Alabama wins; Clemson, Oklahoma and Ohio State lose.Chances of happening: 0.2 percentLikely playoff field: Alabama (>99 percent), Notre Dame (>99), Clemson (64) and … ???Others: Texas (44 percent), Georgia (36), UCF (31), Washington (16), Ohio State (4), Oklahoma (4)This chaotic option isn’t as immediately apparent as the obvious “Georgia beats Bama” doomsday scenario above, but it might end up wreaking just as much havoc. Our model thinks Clemson would still have a reasonable 2-in-3 chance of making the playoff even after losing to Pitt, provided the Sooners and Buckeyes also lose. But the model is doing an algorithmic shruggie at the idea of having to pick the fourth team, which could be any of six schools with at least a 4 percent chance according to the model. The odds of this happening are very low (about 1 in 444), but if it does, it could be the most challenging decision the committee has faced in its five seasons of existence.Check out our latest college football predictions. read more

GST on imports IAF objects to over Rs 100 crore bill for

first_img IBTimes VideoRelated VideosMore videos Play VideoPauseMute0:01/1:36Loaded: 0%0:01Progress: 0%Stream TypeLIVE-1:35?Playback Rate1xChaptersChaptersDescriptionsdescriptions off, selectedSubtitlessubtitles settings, opens subtitles settings dialogsubtitles off, selectedAudio Trackdefault, selectedFullscreenThis is a modal window.Beginning of dialog window. Escape will cancel and close the window.TextColorWhiteBlackRedGreenBlueYellowMagentaCyanTransparencyOpaqueSemi-TransparentBackgroundColorBlackWhiteRedGreenBlueYellowMagentaCyanTransparencyOpaqueSemi-TransparentTransparentWindowColorBlackWhiteRedGreenBlueYellowMagentaCyanTransparencyTransparentSemi-TransparentOpaqueFont Size50%75%100%125%150%175%200%300%400%Text Edge StyleNoneRaisedDepressedUniformDropshadowFont FamilyProportional Sans-SerifMonospace Sans-SerifProportional SerifMonospace SerifCasualScriptSmall CapsReset restore all settings to the default valuesDoneClose Modal DialogEnd of dialog window. COPY LINKAD Loading … Close Can Lockheed Martin F-21 meet Indian Air Force’s long-term strategic goals? Indian Air Force Mirage 2000 fighters.ReutersThe Indian Airforce has made an objection against more than Rs 100 crore of integrated goods and services tax (IGST) levied on various imported items. The IAF imported these items from various countries and has shown as “parts of aircraft” in its financial books. Financial daily, the Economic Times reported that the issue is expected to be tabled at the ministerial level where IAF and the Directorate of Revenue Intelligence (DRI) would discuss more on the issue.As per the sources privy of the development, the IAF argued that these items including electrical and mechanical parts, antennas and electronic spares come under customs tariff heading 8803 which calls for nil or 5% IGST. In contrast, the DRI is of the opinion that these imported spares are not “parts of aircraft” and are imported completely separate items. Notably, these goods are exempted of any duties under the harmonized system nomenclature (HSN) code followed by GST while classifying the goods in five slabs: nil, 5%, 12%, 18%, and 28%. Sukhoi-30MKI (Su-30MKI) fighters integrated with BrahMos supersonic cruise missiles will give Indian Air Force total air superiority on subcontinental air space.@IAF_MCC/twitterOne official said: “The IGST levied on these items is from the period of the inception of GST. The matter is being probed since August last year and, last month, the IAF made a representation before the DRI, Mumbai, contesting the duty citing that these were parts of aircraft and are well within the common HSN code which guides the GST slabs and that these goods attract GST under chapter 8803 that allows nil or 5 % GST.”The issued would be discussed at the ministerial level meeting and IAF would highlight the need of Rs. 100 crore to buy other critical equipment. “Unlike commercial planes where these items are fitted in the aircraft for commercial purposes, IAF aircraft is mainly used for defense purposes and there is a view in the forces that the matter should be taken at the highest level so that IGST on accessories imported by the IAF are exempted,” the official further added. The DRI is arguing that it is following the routine process wherein all the other government agencies are also asked to pay IGST on imports. One of the officials said the IAF could pay the proposed duties and then seek a claim from the government. “The IAF has not been singled out, the DRI found duty evasion of over `300 crores by various private airline and aerospace firms,” he said.last_img

Hasina says democracy on firm footing

first_imgPrime minister Sheikh Hasina is seen taking in doa at an Iftar she hosted for different political parties at her official Ganabhaban residence on MondayAwami League president and prime minister Sheikh Hasina on Monday said democracy in Bangladesh now stands on a solid ground with the economy being strong enough.”Bangladesh is marching forward. Our democracy now stands on a solid base while the economy is strong enough,” she told an iftar party hosted in honour of the leaders of different political parties at her official Ganobhaban residence.The prime minister said Bangladesh has entered the era of a developing country and its continuation has to be maintained.Sheikh Hasina said the government will ensure people’s improved lifestyle through implementing Vision-2021. “We’ll ensure education in all houses,” she said.About the launching of satellite Bangabandhu-1 into the orbit, she said Bangladesh has set its footprint in the areas of sea, air, space and nuclear.Mentioning that there was scarcity of everything in the country once upon a time, the prime minister said the Awami League government through its pragmatic steps banished this scarcity.She said the government will build the country imbued with the spirit of the Liberation War. “We’ll make the country free from hunger and poverty as dreamt by the father of the nation.”Earlier, the prime minister went round different tables set for the guests, exchanged pleasantries with them and enquired about their wellbeing.Before the iftar, a munajat was offered seeking continued peace, progress and prosperity of the nation.Prayers were also offered seeking eternal peace of the departed souls of father of the nation Bangabandhu Sheikh Mujibur Rahman and other martyrs of the 15 August carnage and the martyrs of the liberation war as well as long life and good health of Sheikh Hasina.Speaker Shirin Sharmin Chaudhury, leader of the opposition in parliament Raushon Ershad, Jatiya Party chairman and the prime minister’s special emissary HM Ershad, finance minister AMA Muhith, commerce minister Tofail Ahmed, LGRD and cooperatives minister Khandakar Mosharraf Hossain, social welfare minister Rashed Khan Menon, information minister Hasanul Haq Inu, Bangladesh Nationalist Alliance leader Nazmul Huda and Samyabadi Dal leader Dilip Barua attended the iftar party.Besides, other ministers, advisers to the prime minister, MPs, senior leaders of Awami League, Jatiya Party, Jatiya Party (Manju), Jatiya Samajtantrik Dal and Workers Party were present.last_img read more

Researchers glimpse the inside of a photonic crystal

first_img More information: T. Denis, B. Reijnders, J. H. H. Lee, P. J. M. van der Slot, W. L. Vos and K.-J. Boller. “Mapping individual electromagnetic field components inside a photonic crystal.” Optics Express, Vol. 20, Issue 20, pp. 22902-22913 (2012) DOI: 10.1364/OE.20.022902Also at arXiv:1207.2004 [physics.optics] (—While today’s smart phones, tablets, and other small electronic devices rely on electrical data connections, in the future they may use optical connections in order to become even faster and smaller. Photonic crystals are ideal tools for this purpose, since they can guide and bend light on the nanometer scale. So far, researchers have not been able to look inside photonic crystals to measure how the light intensity is distributed. Now in a new study, a team of researchers from the MESA+ Institute at the University of Twente, The Netherlands, has developed a method that can measure the intensity distribution of light inside photonic crystals. © 2012 Citation: Researchers glimpse the inside of a photonic crystal (2012, October 2) retrieved 18 August 2019 from Scientists shed light on glowing materials How to measure the light intensity inside a photonic crystal: (Top) The photonic crystal, indicated by the ordered yellow circles, is placed between two mirrors. Only one color, blue, resonates. (Middle) When a bead is inserted at a specific location in the cavity and the light intensity is low, a slight color change to green occurs. (Bottom) When the light intensity is strong at the bead location, the color changes even further and becomes red. The right panel indicates how using the bead to change the resonating color can allow the light intensity to be mapped throughout the photonic crystal. Image courtesy of T. Denis To map the strength of the electromagnetic field at different locations inside photonic crystals, the researchers set up an experiment in which they placed a photonic crystal between two aluminum mirrors. Inside the cavity, light bounces back and forth between the mirrors. Since light is a wave, only waves whose wavelengths fit the length of the cavity can build up. In other words, only a specific color can exist inside the cavity. After measuring the crystal’s resonating color, or frequency, the researchers then investigated how the frequency would be altered when they lowered a 2-mm bead hanging from a nylon string inside the crystal. The bead scatters nearby electromagnetic waves, changing the crystal’s frequency in a way that is proportional to the light intensity at that location. By measuring the frequency shift when moving the bead to various locations, the researchers could map the electromagnetic field strength throughout the inside of the photonic crystal. “For example, in the figure above, the cavity limits the build-up of light to blue light,” Denis said. “When placing the bead inside the photonic crystal, this leads to scattering, which changes the light color that resonates in the cavity. The waves have to make a small detour around the scattering object. Therefore, the color where the light resonates is changed, which can be measured. In the figure it varies from green to red depending on the position of the bead. By moving the bead throughout the cavity, this allows us to map the light intensity at all locations by measuring the resulting color shift.”The researchers also explained that the electric field inside the photonic crystal has six components, and each of these components can be measured separately by choosing a bead with a suitable material, shape, and orientation so that only one component contributes to the frequency shift. In the future, the researchers also want to perform modified experiments, such as placing the bead on a carbon nanotube acting as the string. An atomic force microscope could control the nanotube’s position and provide high spatial resolution of the field inside the crystal. Ultimately, the ability to map the inside of a photonic crystal provides a valuable tool for using these devices in future applications. Explore further Journal information: Optics Express The study, which is published in a recent issue of Optics Express, may lead to new insights into photonic crystals that could assist in the development of new applications.As the researchers explain, photonic crystals are materials with an intricate three-dimensional structure that manipulates light in ways similar to how semiconductors control electrons. Photonic crystals have a periodic structure with a length scale on the order of the wavelength of light. An example of a photonic crystal found in nature is the gem opal, which consists of a regular array of tiny silicate spheres that are ordered like atoms in a crystal lattice, but on a length scale a thousand times larger than the atoms in a photonic crystal.A major goal in this area of research is to make photonic crystals interact with light strongly enough to achieve a “photonic band gap,” which is a range of light colors that are prevented from propagating in any direction. Band gaps can result from disorder in a crystal, since disorder leads to localized states that effectively trap light in a cage. This type of control can allow researchers to harness light beams and steer them around tiny optical chips.In order to control light in this way, it’s helpful to know the electromagnetic field distribution inside the photonic crystals. So far, the only optical method to map local fields is near-field scanning optical microscopy, which scans the surface of the crystal. However, this technique has several drawbacks because it cannot probe the fields inside the crystal, whereas the new method presented here can.”We have demonstrated for the first time how to look into the inside of photonic crystals,” lead author Thomas Denis of the University of Twente told “With an astonishingly simple method we were able to map the absolute strength of an individual field component inside a photonic crystal. Such a method should be of high importance for the design of novel photonic crystal devices, such as fast optical interconnects on computer chips.” 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