A Smarter Way to Grow Graphene

first_img Producing graphene from carbon dioxide The current methods of isolating graphene each have problems. The most common, known as micromechanical cleavage, in which sheets are sheared off of a larger crystal, doesn’t reliably produce graphene samples that are large enough for applications.Another method, in which the atomic structure of a substrate is used to seed the growth of the graphene, known as epitaxial growth, doesn’t yield a sample with a uniform thickness of graphene layers, and bonding between the bottom graphene layer and the substrate may affect the properties of the carbon layers.The Brookhaven group based their technique on this second method, except that they were able to grow the graphene in a controlled, layer-by-layer manner. The substrate they chose is the rare metal ruthenium, and while the bottom graphene layer does interact strongly with it, the next layer up is almost completely detached, only weakly electrically coupled to it, and behaves much like free-standing graphene.“This second layer retains the inherent electronic structure of graphene,” Brookhaven physicist Peter Sutter, who led the work, told PhysOrg.com. “Thus, our findings may represent a long-sought route toward rational graphene synthesis and the creation of high-quality graphene for applications in electronic devices and sensors.”Graphene has several properties that make it desirable for electronics, including its very high carrier mobility—that is, electrons in graphene can roam rather freely. Graphene can respond to a single gas molecule, making it very attractive as a detector material for sensors.The Brookaven group’s growth process takes place at high temperatures. To start, the researchers caused carbon atoms to become absorbed within the ruthenium by heating the entire sample to 1150 degrees Celsius (ºC). The sample was then cooled to about 850 ºC, which caused large amounts of the absorbed carbon to rise to the surface of the ruthenium. The carbon formed single-layer lens-shaped islands about 100 micrometers (millionths of a meter) in width, dotting the entire substrate surface.Eventually, the islands grew into a complete first graphene layer. And at about 80 percent coverage, the growth of the second layer began.Sutter and his group observed the growth and studied the graphene’s properties using various instruments, including a scanning electron microscope and a low-energy electron microscope.Citation: Peter W. Sutter, Jan-Ingo Flege and Eli A. Sutter Nature Physics advance online publication, 6 April 2008 (DOI:10.1038/nmat2166)Copyright 2008 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. Citation: A Smarter Way to Grow Graphene (2008, May 14) retrieved 18 August 2019 from https://phys.org/news/2008-05-smarter-graphene.html Graphene, a sheet of carbon just one atom thick, has many potential uses in the electronics industry, but producing these ideal two-dimensional carbon sheets is very difficult and, as a result, their use has been stifled so far. But scientists from Brookhaven National Laboratory may have finally found a way around the issue, devising a method to yield high-quality graphene sheets. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore further A schematic rendering of the first graphene layer (G) grown on the ruthenium substrate (Ru). Image courtesy Peter Sutter, Brookhaven National Laboratorylast_img read more

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Light within a light offers CFL efficiency with incandescent bulb shape

first_img The advantage of the new Energy Smart compact fluorescent lamp (CFL) is that it offers CFL efficiency along with the more aesthetic pleasing appearance of a typical incandescent bulb. The new light has the same size and dimensions of an old 60-watt bulb, which may make it attractive for fixtures in which the bulb is visible, or possibly for inexpensive ceiling fixtures designed to clip on to round bulbs.”The all-glass design, which I said would be out next year, combines that T2 spiral fluorescent tube with an electronics package contained in the neck of the lamp,” John Strainic, GE global product general manager, explains in the video. “So that gives you the profile of an incandescent shape…so it’s like building a ship in a bottle.”Strainic said that some very leading-edge patents were used for the process of cutting and resealing the bulb. The final bulbs will be frosted white, so most likely the inner fluorescent spiral won’t be visible. GE plans to make the new bulb available on December 28 at Target, in January at selected Ace Hardware stores, and everywhere else (including Walmart) around Earth Day 2009 (April 22). via: Gizmodo© 2008 PhysOrg.com A video clip of General Electric’s new Energy Smart CFL bulb, containing a fluorescent bulb in an incandescent-shaped outer bulb. (Commercial bulbs will be frosted, not clear.) Image credit: GE. This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (PhysOrg.com) — In the coming weeks, General Electric will start selling a new “ship in a bottle” lightbulb – a fluorescent spiral bulb trapped inside a traditional incandescent-shaped bulb. Citation: ‘Light within a light’ offers CFL efficiency with incandescent bulb shape (2008, December 12) retrieved 18 August 2019 from https://phys.org/news/2008-12-cfl-efficiency-incandescent-bulb.htmllast_img read more

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Yahoo is Going Portuguese Hound to Outwit Twitter

first_imgYahoo Meme In Brief: Yahoo! integrates ask and search sites This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Explore further According to David Ruiz, a blogger, systems analyst and senior programmer in Brazil, Yahoo has released a Twitter clone called Yahoo Meme in Portuguese. The Yahoo Meme is by invitation only. David Ruiz received his invitation to the alpha-version of the Twitter-like social networking site. Interestingly, Yahoo Meme uses a dog instead of the familiar Twitter bird. Mr. Ruiz says the term “meme” is an adaptation of the scientific observations of Richard Dawkins in his book, “The Selfish Gene”. On the Internet, a “meme” is used to describe a sort of fever of popular content available to everyone. In the Yahoo sense of the term for its new social networking site, Yahoo Meme, it is a term which expresses the notion of free and expanded, within the context of the original idea. Simply put, Yahoo Meme is easy to access and easy to use. A click on the call, sign in and name your meme, attach your url, give a less than a 100 character description and you are Go. A screen lists all the meme images which allows users to verify who is meme-ing you. Users can post videos, images, music and text in the same way as Twitter. The search feature needs some tweaking, but it is pretty new.According to Ruiz, the Alph-phase is closed and he has only a few invites available for distribution. He distinguishes Twitter from Memes conceptually, saying memes is more like the “fever” of the moment. The actual differences between Twitter and Yahoo Memes may be a distinction without a difference. Except Yahoo Memes is in the Portuguese language.© 2009 PhysOrg.com Citation: Yahoo is Going Portuguese Hound to Outwit Twitter (2009, May 15) retrieved 18 August 2019 from https://phys.org/news/2009-05-yahoo-portuguese-hound-outwit-twitter.html Brazil, a Portuguese speaking country is the 10th largest economy in the world and Yahoo has decided to get in on the action by coming up with a clone Twitter. The economic down-turn has affected Brazil to some degree, but its Foreign Minister Guido Mantega has announced it is cautiously optimistic for a turn around at years end. last_img read more

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Google adds voice and video to Google Talk on Android smartphones

first_img(PhysOrg.com) — Users of Google’s Android OS on their Nexus S smartphones can now smile a little more as their friends will be able to see it; Google has (finally) added video and voice chat as a part of a native Android app. Third party apps that let users video chat on their Android phones (Fring, Qik, etc.) have been around awhile, as has a native app on the iPhone (FaceTime); with this move, Google is finally catching up with everyone else by adding both video and voice to Google Talk; something users have been able to do on their personal computers for quite some time. Although, sadly, the new additions will only be available for Nexus S phones (Nexus One phones don’t have a front facing camera) it will likely create waves in the smartphone market as it offers yet another way for users to communicate with one another using their data network, rather than the cell channel, which means users can talk with other users without using any of their voice minutes. More information: googlemobile.blogspot.com/2011 … r-android-phone.html Citation: Google adds voice and video to Google Talk on Android smartphones (2011, May 2) retrieved 18 August 2019 from https://phys.org/news/2011-05-google-voice-video-android-smartphones.html Android 2.3 Gingerbread expected in the next few days Explore further © 2010 PhysOrg.com Google announced the update on their blog and says that the updates will happen over the air, over the next few weeks (for 2.3.4 phones; other 2.3+ devices will have to wait for a future update). The new feature will work with both Wi-Fi and 3/4G Wireless networks (upping the stakes for Facetime which only works with Wi-Fi). Once updated, users will find a video or voice chat button next to their contacts on their contacts list. To connect, all they’ll need to do is click the button.Once updated, users of Nexus S phones will be able to video and voice chat as well as text with other Nexus S phone users; they’ll also be able to do the same with those running Google Talk on their PC or with tablet users running Honeycomb. Text messages will be overlaid on the video screen and video can be paused while other apps are run (the audio keeps going).Clearly Google, still the new player in town, is serious about its venture into the smartphone market, and will continue to add functionality to Android as it moves from a follower, to a leader in the field. 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

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University of Pennsylvanias PR2 robot learns to read w video

first_img More information: www.ros.org/wiki/literate_pr2 © 2010 PhysOrg.com PR2 robot reading indoor signs and more from the GRASP lab, University of Pennsylvania. One robot specific issue to deal with is the font. An average person can encounter hundreds of fonts during their lifetime as a reader. For a human the ability to distinguish the same letter in different fonts is innate, for all but the most ornate or obtuse fonts. A robot is a bit more literal, and requires more processing power and learning time to keep track of 200 different ways to write the letter L or Z. If you happen to have an ROS platform robot you can download the software for the upgrade from the school for free. University of Ulster celebrates acquisition of PR2 robot by having it solve Rubik’s cube Explore further Graspy is learning to read in the same way that a human toddler would learn. It begins by watching the words in order to recognize the shapes that the words take. Then it attaches a meaning to the shapes, associating the sound of the letter with its look. Then the process of sounding out the words begins. As new and less familiar words are brought into the mix, Graspy will try to match them to known words. Far from the simple word recognition of the current generation of text to speech systems, this system has the capacity to learn. 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: University of Pennsylvania’s PR2 robot learns to read (w/ video) (2011, May 20) retrieved 18 August 2019 from https://phys.org/news/2011-05-university-pennsylvania-pr2-robot-video.html (PhysOrg.com) — Researchers at the University of Pennsylvania’s GRASP Lab have added new functionality to their Robot PR2. The Robot PR2, which has been given the nickname Graspy, has the ability to read for itself. Graspy can read anything from simple signs to full-length warnings. At this point it has yet to work with longer texts, but in time it may be able to read you a bedtime story.last_img read more

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CERN teams post Higgs Boson papers one ups its sigma level of

first_img © 2012 Phys.org 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. ATLAS preprint: arxiv.org/abs/1207.7214CMS preprint: arxiv.org/abs/1207.7235 Explore further Endgame for the Higgs Boson Journal information: arXiv More information: Citation: CERN teams post Higgs Boson papers – one ups its sigma level of certainty (2012, August 2) retrieved 18 August 2019 from https://phys.org/news/2012-08-cern-teams-higgs-boson-papers.html (Phys.org) — The two teams working (and causing headlines around the world) at the CERN Large Hadron Collider CMS and ATLAS, have both uploaded papers describing their work in searching for evidence of the particle that is believed to explain why matter sticks together, the elusive Higgs Boson, to the preprint server arXiv. In their paper, ATLAS has bumped up its sigma level of certainty from 5.0 to 5.9 while CMS has kept its level at the 4.9 to 5 range. The sigma levels are indicators physicists use to gauge how sure they are of their results. 5.0, for example indicates the researchers believe there is a five in ten million chance that the signals they’ve seen are due to something other than what they believe it to be; in this case, evidence of a Higgs boson. 5.9 would bump up the likelihood to two in a billion.It’s important to note that both teams are still calling what they’ve found to be something “Higgs like” rather than boasting of the discovery of the actual boson. This is because neither team has actually seen the boson, instead, they rely on measurements of particles that are thought to come into existence as a Higgs decays; according to theory, it’s only supposed to last for the tiniest fraction of a second, too little time to actually see or record it. It’s also important to note that the sigma numbers aren’t measurements of how certain the researchers are that what they’ve found is the Higgs, instead they are numbers that represent how certain the teams are of what they’ve measured. This means it’s possible that all their measurements and numbers are right, but whatever caused them to come about isn’t an actual Higgs, but something else that is both close to a Higgs and un-described in the Standard Model. There is no statistical number to demonstrate how sure they are of that.What this all means is that both teams, and most physicists who study such things, are pretty sure that the work at CERN has proven that the Higgs boson does indeed exist and that further study will one day allow for the removal of the Higgs-like tag. On the other hand, if it turns out that what the teams have been measuring is due to something else, well, that will mean having to edit the Standard Model, which is a description physicists have come up with to describe all of the ingredients at their most basic level, that make up everything that exists. This artist’s graphic shows the underground ATLAS detector along the 17-mile subsurface tunnel, the Large Hadron Collider at the Swiss-Franco border. Protons will smash into each other with unprecedented impact speeds.last_img read more

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Boronbased atomic clusters mimic rareearth metals

first_img More information: “Mimicking the magnetic properties of rare earth elements using superatoms” Shi-Bo Cheng, PNAS DOI: 10.1073/pnas.1504714112 An Alchemist’s Dream: Superatoms Mimic Elements Prior studies by this group demonstrated that TiO-, ZrO-, and WC- were similar to Ni-, Pd-, and Pt-, respectively. This work had established that by simply counting the valence electrons of the atomic units comprising the cluster, certain clusters of atoms could behave as a superatom counterpart to isovalent, atomic anions. They wanted to apply this same technique to a boron-doped lanthanum, which should have six valence electrons in its neutral LaB cluster. Furthermore, if the LaB cluster does behave like Nd, then there should be four unpaired electrons in the cluster’s valence, mimicking neodymium’s magnetic properties.Using photoelectron spectroscopy, Cheng et al. found that LaB adiabatic ionization energy (ADE, also the electron affinity) measurement was 0.909 +/- 0.025 eV. Vibrational frequencies were measured with four distinct peaks around the largest peak that represents neutralization of the LaB- anion.Experimental results were compared to theoretical calculations in which the lowest energy state was discerned from various spin multiplicities of both LaB- and LaB. Theoretical calculations showed that the lowest energy conformation of LaB- has three unpaired electrons (spin multiplicity of 4) and LaB has four unpaired electrons (spin multiplicity of 5). Theoretical vibrational energies correspond to the measured vibrational energies found using photoelectron spectroscopy. Additionally theoretical ADE and vertical detachment energy (VDE) of both LaB- was very close to the experimental values with LaB- ADE calculated to be 0.947 eV. This provides strong evidence that LaB likely has four unpaired electrons and six electrons, total, in its valence, which is analogous to Nd. By combining the vibrationally-resolved photoelectron spectroscopy and high-level theoretical calculations, Cheng et al. have provided compelling evidence that LaB has four unpaired electrons and six electrons, total, in its valence, which is analogous to Nd. Similar experiments were further performed to examine whether such similarity is preserved between another boron-doped superatom cluster (NdB) and its isovalent rare earth counterpart europium. Experimental and theoretical results confirmed that the lowest energy state of NdB has seven unpaired electrons, analogous to europium’s valence. Rare Earth elements, found in the f-block of the periodic table, have particular magnetic and optical properties that make them valuable commodities. This has been particularly true over the last thirty years as more technologies use rare earth metals in their components, including audio speakers, computer hard drives, camera lenses, MRI imaging, television screens, and computer screens. Journal information: Proceedings of the National Academy of Sciences 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.center_img Citation: Boron-based atomic clusters mimic rare-earth metals (2015, April 17) retrieved 18 August 2019 from https://phys.org/news/2015-04-boron-based-atomic-clusters-mimic-rare-earth.html © 2015 Phys.org While these rare earth elements are found within the Earth’s crust, the post-mining purification process can create hazardous waste, prompting some researchers to find cheaper and more environmentally friendly alternatives. Shi-Bo Cheng, Cuneyt Berkdemir, and A. W. Castleman, Jr. from the Department of Chemistry and Physics at Pennsylvania State University have shown that boron-doped lanthanide superatom clusters mimic the valence electron configuration of certain rare earth elements, and may serve as rare earth analogs. Their work is published in the Proceedings of the National Academy of Sciences.Cluster chemistry involves combining atoms or molecules in such a way that they are considered something in between an isolated atomic or molecular species and bulk material. This field gained prominence when nanomaterials and semiconductors became popular areas of research. Superatom clusters are a subcategory of cluster chemistry in which a cluster of atoms behaves as though it were single atomic species. The combined valence electrons in a superatom cluster are no longer identified with a particular nucleus, but behave as if they are the valence of a single atomic structure.Early research into superatom clusters found that certain atoms or atomic combinations tended to cluster into particular numbers, known as magic numbers. Cheng et al.’s research looked at what they have dubbed a “magic boron” counting rule, in which boron combined with a lanthanide in a superatom cluster will contribute three unpaired electrons to the number of unpaired electrons in the lanthanide atom’s valence.Cheng et al. investigated whether the magnetic properties of the diatomic boron-doped lanthanum clusters and boron-doped neodymium clusters behaved like neodymium (Nd) and europium (Eu), respectively. They theorized that the spin characteristics of these particular superatom combinations should be similar to those of their isovalent rare earth counterparts, and would therefore display analogous magnetic properties. They first constructed the superatom cluster, then tested its valence properties using photoelectron spectroscopy and compared their experimental results to theoretical calculations. Explore furtherlast_img read more

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A certain protein could possibly be the key to understanding navigation in

first_img Explore further Citation: A certain protein could possibly be the key to understanding navigation in birds (2018, April 4) retrieved 18 August 2019 from https://phys.org/news/2018-04-protein-possibly-key-birds.html © 2018 Phys.org Migratory birds eye-localized magnetoreception for navigation 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: Atticus Pinzon-Rodriguez et al. Expression patterns of cryptochrome genes in avian retina suggest involvement of Cry4 in light-dependent magnetoreception, Journal of The Royal Society Interface (2018). DOI: 10.1098/rsif.2018.0058AbstractThe light-dependent magnetic compass of birds provides orientation information about the spatial alignment of the geomagnetic field. It is proposed to be located in the avian retina, and be mediated by a light-induced, biochemical radical-pair mechanism involving cryptochromes as putative receptor molecules. At the same time, cryptochromes are known for their role in the negative feedback loop in the circadian clock. We measured gene expression of Cry1, Cry2 and Cry4 in the retina, muscle and brain of zebra finches over the circadian day to assess whether they showed any circadian rhythmicity. We hypothesized that retinal cryptochromes involved in magnetoreception should be expressed at a constant level over the circadian day, because birds use a light-dependent magnetic compass for orientation not only during migration, but also for spatial orientation tasks in their daily life. Cryptochromes serving in circadian tasks, on the other hand, are expected to be expressed in a rhythmic (circadian) pattern. Cry1 and Cry2 displayed a daily variation in the retina as expected for circadian clock genes, while Cry4 expressed at constant levels over time. We conclude that Cry4 is the most likely candidate magnetoreceptor of the light-dependent magnetic compass in birds.center_img Journal information: Journal of the Royal Society Interface Credit: CC0 Public Domain Birds that are able to migrate great distances obviously have some form of navigation system—they stop at the same places and have very clear destinations in mind. But how do they do it? In recent years, some in the field believed it had to do with iron-rich cells in their beaks serving as mini-compasses, but this theory has had some problems, such as how the birds translate beak sensations to directional signals. In this new effort, the researchers suggest it is not the cells in the beak that are responsible, but a type of protein that exists in their eyes. The researchers came to this conclusion by studying the brains, muscles and eyes of zebra finches. More specifically, they studied Cry1, Cry2 and Cry4, proteins associated with the circadian clock. The researchers found that Cry1 and Cry2 levels tend to rise and fall throughout each day, but Cry4 remains constant, suggesting it has another purpose.The researchers chose to study these particular proteins because they are made of a type of molecule that sometimes has an odd number of electrons, leaving some unpaired, and thus sensitive to a magnetic field. They also found that Cry4 tends to exist in clusters in a part of the bird retina that tends to get a lot of light and which is sensitive to blue light—this is important because prior studies have shown that birds are only able to navigate when blue light is available. Taken together, the evidence suggests that the protein plays a strong role in navigation.The study does not prove that the Cry4 protein is the key to bird navigation, but it makes a strong case for it. Earlier this month, a Danish and German team of researchers studying robins found that Cry4 levels also remain constant each day, but rise during the migratory season. A team of researchers at Lund University has found evidence that suggests a certain protein plays a prominent role in bird navigation. They have published their findings in Journal of the Royal Society Interface.last_img read more

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Craft for generations

first_imgShrujan, a grass-root, craft-revival, and income-generation organization, established in 1969, organised the largest exhibition of Hand Embroidered Products from 05 July to 08 July in the Aga Khan Hall. The exhibition focused mainly on saris, shawls, and dupattas, among other garments.  Besides displaying 16 different styles of Hand Embroidery, made by craftswomen from 10 communities of the Kutch region of Gujarat, the exhibition presented a whole new array of vibrant colours and high-quality fabric to enthral any person with an eye and appreciation for art, textile, or embroidery. Also Read – ‘Playing Jojo was emotionally exhausting’Hiral Dayal, Trustee Shrujan, said, ‘Each of the 16 hand-embroidery styles from this region resembles a piece of jewellery. More than 95% of our customers who appreciate the uniqueness of this art have placed great trust in us for delivery of the best-quality and highly durable hand-embroidered finished products.’ In addition to focusing on a new range of designs for saris, shawls, dupattas, and other garments, the exhibition showcased new styles of not only garments but also stitches. Visitors to the Shrujan Hand Embroidery Exhibition found an eclectic mix of traditional embroidery on contemporary apparels, including men’s kurtas as well as silk and woolen jackets. Also Read – Leslie doing new comedy special with Netflix The years of research on hand embroidery from Kutch and its communities was evident on the resplendent display of stitches and vibrant colors. Besides its classic range, the highlights of the event were colourful, embroidered Maheshwari dupattas and stoles; and tie-and-dye skirts and cholis. Hand-embroidered fabrics that 3,500 craftswomen living in 100 remote villages of Kutch have fashioned into high-quality products were appreciated by all. At its previous exhibition, Shrujan presented the first book and instructional film entitled Under the Embroidered Sky: the Embroidery of the Ahirs of Kutch, that showed the research work and documentation and filming of the embroidery styles of other communities. For countless generations, this craft had been passed on from the mother to the daughter. However, with the oral tradition of teaching and learning falling out of favor, exploration of other methods of safeguarding the wisdom of the craft has become imperative.last_img read more

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BJP a sinking ship

first_imgHe said the BJP will lose badly in the upcoming Assembly polls in spite of adopting “gimmicks” everyday to avert its defeat.“BJP knows that it is going to lose this election very badly and this is why this party has finally roped in Kiran Bedi so that she can be made scapegoat.“But no one can save this party now. This is a sinking ship and yet a new gimmick is being adopted everyday but the party will lose badly. BJP has now started losing its breath,” he said, addressing a rally at Seelampur constituency here. Also Read – Company director arrested for swindling Rs 345 croreKejriwal said that BJP has been baffled by the low turnouts in the rallies that were addressed by its MPs.“BJP leaders and its pool of 200 MPs have failed to pull the masses in their rallies in Delhi. Even Modi’s rally was super flop,” he claimed. Kejriwal also referred to BJP MP Sakshi Maharaj’s controversial remarks where he asked Hindu women to have at least four children, saying that the BJP was “running after women”.“Before the election, BJP leaders promised to provide full safety and security to women, but after poll, this party is running after women. They are asking our women to give birth to four children. I ask them, whether our women are child bearing machines?,” he said.last_img read more

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