Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Carrier pigeon. Credit: Wikimedia. Citation: Carrier Pigeon Faster Than Broadband Internet (2009, September 11) retrieved 18 August 2019 from https://phys.org/news/2009-09-carrier-pigeon-faster-broadband-internet.html 10 years after: Promised reform in South African telecommunications fails (PhysOrg.com) — In South Africa, a carrier pigeon carrying a 4GB memory stick proved to be faster than the ADSL service from the country’s biggest web firm, Telkom. Winston the pigeon took one hour and eight minutes to carry the data across the 60-mile course, and it took another hour to upload the data. During the same time, the ADSL had sent just 4% of the data. The race was held by an IT company in Durban, South Africa, called Unlimited IT. One of Unlimited IT’s employees complained about the slow speed of data transmission on ADSL, saying that data would get transferred faster by carrier pigeon. To highlight just how slow the broadband internet is, the company decided to test that claim. The 11-month-old Winston flew 60 miles from Unlimited IT’s call center in Howick to another office in Durban. To make sure that the bird didn’t have an unfair advantage, Unlimited IT imposed some rules on its website, including “no cats allowed” and “birdseed must not have any performance-enhancing seeds within.” Hundreds of South Africans followed the race on social networking sites Facebook and Twitter.For its part, Telkom said that it was not responsible for Unlimited IT’s slow broadband speeds. A Telkom spokesperson said that they had made several recommendations to Unlimited IT to improve its service, but none of the suggestions had been accepted.As the BBC reports, South Africa is one of the countries that could benefit from three new fiber optic cables being laid around the African continent to improve internet service.via: BBC News© 2009 PhysOrg.com
Month: August 2019
The pCubee consists of five LCD screens arranged as a cubic “fish tank” box that viewers can pick up, tilt, shake or turn to watch the 3D content or play games with virtual objects that seem to be within the box. Instead of stereoscopy, the device uses a principle called motion parallax, which is one of the means by which we usually perceive depth in a three dimensional scene. Motion parallax is a cue the brain is able to use to sense depth, because the movements of objects across our field of view depends on their relative distance from us. Having the box move means viewers do not need to move their heads to see the effect. 3D TV — Without the Glasses (w/ Video) More information: The pCubee will have many more applications than 3D games, since it also has the potential to become a CAD-CAM platform, and could be used in museum displays. It was awarded Best Demonstration at the 2009 ACM International Conference on Multimedia in Beijing. * UBC research page: hct.ece.ubc.ca/research/pcubee/* pCubee site: www.cubee.ca/ © 2010 PhysOrg.com pCubee: a Perspective-Corrected Handheld Cubic Display The five flat-panel LCD screens on the sides of the box are driven by three graphics pipelines. The perspective rendered on the screens is kept synchronized with the user’s view by a motion tracker that monitors both the user’s head and the pCubee box. That, and the real-time physics simulation engine, make the display look like a tank containing real objects. The box allows you to view a static 3D scene, or you can manipulate the box to navigate through the scene or play with objects colliding in the scene. You can also manipulate virtual objects using a stylus.pCubee was developed at the Human Communication Technologies Laboratory at the University of British Columbia in Canada. Leader of the engineering team, Sidney Fels, said the group wanted to offer “a fish-tank-like experience” in a handheld device. Fels hopes the pCubee will be commercially available soon, but the researchers are continuing to refine the design, and may replace the current LCD panels with OLED screens. They are also building pCubees in different sizes for different applications.
Canada privacy office launches new Facebook probe (PhysOrg.com) — A Sunday blog post by self-described hacker, writer and entrepreneur Nik Cubrilovic has set off a firestorm of discussions and accusations that Facebook violates user privacy in the form of tracking via leftover cookies. Cubrilovic accused Facebook of using cookies to track users even after users have logged off. “Logging out of Facebook only de-authorizes your browser from the web application,” he said. “A number of cookies (including your account number) are still sent along to all requests to facebook.com.” Explore further Citation: Facebook answers privacy flap over leftover cookies (2011, September 27) retrieved 18 August 2019 from https://phys.org/news/2011-09-facebook-privacy-leftover-cookies.html © 2011 PhysOrg.com This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. Facebook “alters” tracking cookies when you log out instead of deleting them. Cubrilovic’s findings were from his analysis of HTTP headers sent by browsers to Facebook.com. The solution, he said, is to delete every Facebook cookie in your browser, or to use a separate browser for Facebook interactions. The story quickly propagated as did news of Facebook employee responses that Facebook’s millions of users should not be bothered.Facebook did not deny that cookies remain even after the user has logged out. What Facebook did seek to correct was any notion that leftover cookies were used to snoop.Facebook engineer Arturo Bejar said that Facebook uses data from logged-out cookies to prevent spamming, phishing and other security risks. An extended Facebook response with similar assurances came from Gregg Stefanci, a Facebook engineer. Stefani defended Facebook’s intentions as user-centric, and not for profiteering by snooping. “We don’t have an ad network and we don’t sell people’s information.” Stefanci said. “Rather, the logged-out cookies are used for safety and security protections.”One example of user protection, he said, was disabling registration if an underage user tries to re-register with a different birth date. Another purpose was helping people recover hacked accounts, and identifying shared computers to discourage the use of ‘Keep me logged in.’While Facebook staffers’ reactions defending Facebook have been quite clear, a stinging sentence on Cubrilovic’s Sunday blog is feeding news posting after news posting: “This is not what ‘logout’ is supposed to mean.”The cookies flap comes at a time when privacy watchdogs are worried about Facebook’s new Timeline feature and are preparing a letter to the Federal Trade Commission to look into the sharing of information via Timeline. The Electronic Privacy Information Center is especially concerned over Timeline, a new design for a profile page. Jeff Chester of the Center for Digital Democracy believes that the redesign is part of an effort to boost data collection prior to an IPO.
© 2012 Phys.org Credit: ACS DNA falls apart when you pull it Citation: Researchers capture high contrast image of band of DNA fiber (2012, December 3) retrieved 18 August 2019 from https://phys.org/news/2012-12-capture-high-contrast-image-band.html (Phys.org)—A research team in Italy has succeeded in capturing a high contrast image of a band of DNA fiber – the closest anyone has ever come to taking a photograph of a single strand of DNA. The team has outlined the process they used to create the image in their paper published in Nano Letters. More information: Direct Imaging of DNA Fibers: The Visage of Double Helix, Nano Lett., Article ASAP. DOI: 10.1021/nl3039162AbstractDirect imaging becomes important when the knowledge at few/single molecule level is requested and where the diffraction does not allow to get structural and functional information. Here we report on the direct imaging of double stranded (ds) λ-DNA in the A conformation, obtained by combining a novel sample preparation method based on super hydrophobic DNA molecules self-aggregation process with transmission electron microscopy (TEM). The experimental breakthrough is the production of robust and highly ordered paired DNA nanofibers that allowed its direct TEM imaging and the double helix structure revealing. Journal information: Nano Letters Up till now the only visual verification scientists have had that proves that DNA does indeed exist in its famous double helix shape, has come about through a process known as X-ray crystallography, whereby beams of x-rays are directed at a band of crystallized DNA fibers resulting in a bunch of dots displayed on photographic film; which in turn have to be interpreted by complex mathematical formulas. Thus, its shape has been inferred rather than captured directly.This new approach comes a lot closer. It’s still not possible to see the double helix, but it is possible to see the DNA strands as part of a chord. To take the picture, the team built an extremely small structure made of quick drying silicon that consisted of a base with tiny holes drilled in it – between the holes, were very small tower type structures. When a drop of a liquid solution with a band of DNA in it was placed on the structure and allowed to dry, the single band was caused to span the distance between two of the towers, directly over one of the holes. To take the picture, electrons were fired from an electron microscope up through the hole. The result is an extremely fuzzy image of six DNA molecules wrapped around a core made of a seventh – individual strands can be seen, but they only hint at what scientists believe are double helixes. The reason a band of several strands was used was because a single strand would have been destroyed by the electron beam.The researchers write that they are optimistic that further work (reducing the amount of electrons fired up through the hole, etc.) will eventually allow for capturing an image of a single DNA molecule existing as a double helix, allowing people everywhere to finally see for themselves one of the main molecules responsible for allowing us to grow into the unique beings we are. Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
Schematic diagram of MS NPs serving as an intratumoral DOA for specific cancer-starving therapy. Activated by the acidic tumour microenvironment, the MS NPs produce reactive silane to give rise to an efficient deoxygenation effect and produce in situ SiO2 blockers in tumour blood capillaries, which subsequently prevent undesired reoxygenation. The deoxygenated tumour with no further oxygen supply will suffocate in the absence of the necessary energy metabolism. MS NP here is the PVP-modified Mg2Si nanoparticles. Journal information: Nature Nanotechnology New nanoparticle-based contrast agent that is pH dependent More information: Chen Zhang et al. Magnesium silicide nanoparticles as a deoxygenation agent for cancer starvation therapy, Nature Nanotechnology (2017). DOI: 10.1038/nnano.2016.280AbstractA material that rapidly absorbs molecular oxygen (known as an oxygen scavenger or deoxygenation agent (DOA)) has various industrial applications, such as in food preservation, anticorrosion of metal and coal deoxidation. Given that oxygen is vital to cancer growth, to starve tumours through the consumption of intratumoral oxygen is a potentially useful strategy in fighting cancer. Here we show that an injectable polymer-modified magnesium silicide (Mg2Si) nanoparticle can act as a DOA by scavenging oxygen in tumours and form by-products that block tumour capillaries from being reoxygenated. The nanoparticles are prepared by a self-propagating high-temperature synthesis strategy. In the acidic tumour microenvironment, the Mg2Si releases silane, which efficiently reacts with both tissue-dissolved and haemoglobin-bound oxygen to form silicon oxide (SiO2) aggregates. This in situ formation of SiO2 blocks the tumour blood capillaries and prevents tumours from receiving new supplies of oxygen and nutrients. Citation: Study shows that nanoparticles serve as a good tumor deoxygenation agent (2017, January 20) retrieved 18 August 2019 from https://phys.org/news/2017-01-nanoparticles-good-tumor-deoxygenation-agent.html (Phys.org)—One target therapy in cancer research is to suffocate the tumor. Cells need oxygen to survive so researchers have focused on methods for cutting off the blood supply to the tumor. Very little research has involved the direct removal of oxygen within the tumor. Part of the reaction mechanism involves the formation of Si4-, which is highly sensitive to acid. This is important because the tumor environment tends to be acidic compared to normal tissue (pH~6.4), and pH sensitivity may help with tissue specificity. To investigate the pH sensitivity of their deoxygenation agent, Zhang et al. placed their nanoparticles in a dialysis bag, which were then immersed in buffer solutions of varied pH values within closed tubes. In acidic conditions, the nanoparticles irreversibly decreased the level of oxygen, but were unreactive in neutral pH. Furthermore, SiO2 aggregates formed in situ that served to block a simulated capillary.Additional studies demonstrated that the MgSi2 nanoparticles demonstrated very little cytotoxicity until they encountered the acidic environment of the cancer cell. Using MCF-7 human breast adenocarcinoma cells, Zhang et al. observed that the combination of acid and nanoparticles led to cell efficient hypoxia. Furthermore, cell proliferation decreased, which is likely due to mitochondrial damage from deoxygenation.In vivo studies involving bilateral 4T1 xenotumor-bearing mice demonstrated that Mg2Si nanoparticles served as efficient deoxygenation agents. Each mouse was injected with the nanoparticle deoxygenation agent in the right tumor and with saline solution as a control in the left tumor. Measurements of blood oxygen saturation levels after ten minutes showed little change in the control tumor and a drastic reduction in oxygen in the test tumor. Oxygen reduction continued for three hours in the tested tumor until tests on both the hemoglobin-bound oxygen and blood oxygen showed complete depletion within the tumor. Notably, PET/CT images show that hypoxia occurred within the tumor and not in the surrounding tissues.Additional observations from the in vivo study showed that the tumors that received Mg2Si nanoparticles demonstrated a slower growth rate compared to controls and after twenty-four hours, although cell proliferation was not slowed down as significantly as in the in vitro studies. These cells showed evidence of fibrosis, necrosis, and apoptosis. Additionally, magnesium was quickly eliminated from the body while silicon was eventually eliminated.Overall, this research provides a compelling proof-of-concept for the use of PVP-modified Mg2Si nanoparticles as potential candidates for use as a tumor-targeted deoxygenating agent. The authors point out that future research would involve exploring surface modifications of the nanoparticles to tailor the length of time the nanoparticles can travel through the blood stream. To this end, a group of researchers from the Shanghai Institute of Ceramics, Chinese Academy of Sciences and the East China Normal University have developed a deoxygenation agent using polyvinyl pyrrolidone modified Mg2Si nanoparticles. This agent is pH sensitive, efficiently consumes oxygen, and one of the products of oxygen consumption also forms aggregates that could potentially block blood vessels. Preliminary mouse studies show tumor hypoxia and good biocompatibility. Their work appears in Nature Nanotechnology.There are several important qualities for a good tumor-starving agent. For one, the agent must be biocompatible which negates the use of heavy metals for oxygen absorption. Additionally, the agent must be efficient at deoxygenation and serve as a long-term oxygen scavenger including preventing re-oxygenation of deoxygenated tumors through undamaged blood vessels. And, as always, any cancer treatment needs to target tumors without damaging healthy tissue, and the agent should be easily injectable by syringe.In the current research, Zhang et al. developed polyvinyl pyrrolidine (PVP)-modified Mg2Si nanoparticles that have several of the qualities for a good tumor-starving agent. Importantly, the main components, magnesium, silicon dioxide, and water are biocompatible. Additionally, the reaction mechanism forms a highly reactive O2 scavenger, SiH4, which serves to make these nanoparticles highly efficient at scavenging oxygen.In order to make injectable nanoparticles, Zhang et al. developed a self-propagating high-temperature synthesis in an oxygen-argon atmosphere. This allows the nanoparticles to remain dispersed in the liquid, rather than form clusters, so that they are injectable into tissue. This synthesis takes advantage of the formation of MgO by-product that halts the continual formation of Mg2Si aggregates. © 2017 Phys.org Explore further This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.
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: S Hubrig et al. Magnetic and pulsational variability of Przybylski’s star (HD 101065), Monthly Notices of the Royal Astronomical Society (2018). DOI: 10.1093/mnras/sty889Magnetic and pulsational variability of Przybylski’s star (HD101065) arXiv:1804.07260 [astro-ph.SR] arxiv.org/abs/1804.07260 AbstractSince its discovery more than half a century ago Przybylski’s star (HD101065) continues to excite the astronomical community by the unusual nature of its spectrum, exhibiting exotic element abundances. This star was also the first magnetic chemically peculiar A-type star for which the presence of rapid oscillations was established. Our analysis of newly acquired and historic longitudinal magnetic field measurements indicates that Przybylski’s star is also unusual with respect to its extremely slow rotation. Adopting a dipolar structure for the magnetic field and using a sine wave fit to all reported longitudinal magnetic field values over the last 43yr, we find a probable rotation period P_rot ~ 188yr, which however has to be considered tentative as it does not represent a unique solution and has to be verified by future observations. Additionally, based on our own spectropolarimetric material obtained with HARPSpol, we discuss the impact of the anomalous structure of its atmosphere, in particular of the non-uniform horizontal and vertical distributions of chemical elements on the magnetic field measurements and the pulsational variability. Anomalies related to the vertical abundance stratification of Pr and Nd are for the first time used to establish the presence of a radial magnetic field gradient. © 2018 Phys.org Magnetic fields discovered in two hot evolved stars European astronomers have conducted a study of Przybylski’s star and found that it takes almost 200 years to fully rotate on its own axis. The finding, which could have implications for the understanding of chemically peculiar stars, is reported April 19 in a paper published on the arXiv pre-print repository. Journal information: Monthly Notices of the Royal Astronomical Society LSD Stokes I (bottom), Stokes V (middle), and diagnostic null (N) spectra (top) obtained for HD 101065 on four nights between 2015 and 2017. The LSD spectra were calculated using eight different line lists, indicated in each panel. For each panel, spectra for 2015 June 5, 2016 June 16, 2017 June 4, and 2017 June 7 are shown from bottom to top; the last three are shifted upwards for better visibility. The LSD Stokes I, Stokes V, and diagnostic null (N) spectra at the top show all four spectra overplotted. Credit: Hubrig et al., 2018. Explore further Citation: Przybylski’s star is an extremely slow rotator, study finds (2018, May 1) retrieved 18 August 2019 from https://phys.org/news/2018-05-przybylski-star-extremely-rotator.html Located some 370 light years away from the Earth, Przybylski’s star (also known as HD 101065) is a rapidly oscillating Ap star (a type of chemically peculiar star) in the constellation of Centaurus. The star has been the subject of numerous observations, as it fascinates astronomers mainly due to its exotic chemical composition. However, although many of basic properties of Przybylski’s star have been uncovered by previous studies, its rotation period remains a mystery. What is known is that in general, Ap stars could have rotation periods ranging from a half-day to even 300 years.Now, a team of astronomers led by Swetlana Hubrig of the Leibniz Institute for Astrophysics Potsdam in Germany, presents a new research regarding Przybylski’s star, which focuses on magnetic and pulsational variability of this object. The study, based on observations performed between June 2015 and June 2017 with the use of the High Accuracy Radial velocity Planet Searcher polarimeter (HARPSpol) at ESO’s 3.6 m telescope in Chile, has also found that the star, besides its chemical peculiarity, is also unusual when it comes to its rotation.”Our analysis of newly acquired and historic longitudinal magnetic field measurements indicates that Przybylski’s star is also unusual with respect to its extremely slow rotation,” the researchers wrote in the paper.Hubrig’s team found that the probable length of the rotation period of Przybylski’s star is about 188 years. This calculation was made by analyzing all available longitudinal magnetic field measurements and adopting a dipolar structure of the magnetic field of the star.However, the researchers underlined that the estimates made by them are tentative and need further studies to confirm them. Therefore, they added that their findings regarding the rotation period should not be considered as a unique solution at the moment.”Our estimation of a 188 yr period should thus not be considered as a unique solution, given the time coverage of the longitudinal magnetic field measurements of 43 yr, which represents a lower limit on the true rotation period of HD 101065,” the paper reads.According to astronomers, the discovery of a very long rotation period of Przybylski’s star along with the previous detection of slow rotation in six other magnetic Ap stars suggests the possible existence of other not yet identified slowly rotating Ap stars.They concluded that further observations of such stars could be very important in improving our knowledge about their formation and processes behind their slow rotation. These processes are not yet identified by astronomers. It is generally assumed that Ap stars are slow rotators because of magnetic braking and that most of the angular momentum is lost in the pre-main-sequence phase.
If you have a fragrance fetish, here is some good news. Delhi Tourism, in association with Government of Delhi and Incredible India, is back with the third Itra and Sugandhi Mela to entice Delhiites with the power of fragrances.The Mela has a lot in store for all. On display are the most unique and extraordinary itra, agarbattis, scented candles, perfumes, room fresheners and many other scented products available.Attar or itra is mainly produced in Kannauj in Uttar Pradesh. The origin of Also Read – ‘Playing Jojo was emotionally exhausting’ itra can be traced back to Kannauj, the city of itra and lithas. It is also produced in Hasain in Uttar Pradesh and Ganjam in Odisha, where rose and kewda itra and oil, in particular, are manufactured. Itra is marketed in large quantities in Lucknow, Hyderabad, Secunderabad, Delhi and Mumbai.Apart from the regular products for sale, there will be live demonstration on Panchkarma, lectures on perfumery and aromatherapy, perfume making on the spot. Visitors will also witness live demonstration on the art and science behind the process of rose water distillation and live demonstration of shave with natural aroma.Visitors will also get to see and learn how agarbattis and dhoopbattis are actually made. The art of making handmade leather bottle (Kuppi) will also be put up. Apart from these, there will be quiz shows for children and competitions like slogan writing for both children and adults.Go for this one.DETAILAt: Dilli Haat, Pitampura When: 1-3 March Timings: 11 am- 9 pm
It’s not often that one gets to witnesses an art work which reflects, rural and the contemporary forms together. Vivid use of colours and memory markers blend perfectly with the themes of her paintings and this is the iconic trademark of the artist, Madhvi Parekh. She started with a thought – to do something of her own. Over the years she has exhibited her work in the country and overseas. Shrishty Mishra catches up with the artist. Read on…What inspired you to paint? When did you start? Also Read – ‘Playing Jojo was emotionally exhausting’I always wanted to do something of my own and I was always attracted to paintings. In 1964 I started pursuing art on my own. The rich folk traditions of picture making in Gujarat helped my interest.Do you have any formal training?No, I am a self taught artist, I kept exploring over the years. My works are refections of my childhood memories and my village.Where do you get your inspirations from?I observe things. Every time something or other catch my attention and serves as an inspiration for me. Also Read – Leslie doing new comedy special with NetflixYou use very vivid colours on your medium, any special reason for that?I belong to Gujarat, art and culture there is extremely colourful and colours to me represent sensitivity so I use them a lot. It is a part of where I come from.What was the inspiration behind your latest exhibition Last Supper?I visited art galleries to see works of other artists; I traveled a lot. Recently I was in Israel and Moscow where beauty of churches inspired me to paint. The calmness and serenity I felt in those churches helped me with this complete my work and influenced me. How much time it took to complete the exhibition?It took me around a year to complete the work for this exhibition.
Scheduled over four days in the Capital, the Indian Classical Music and Dance Festival 2014 will be hosting numerous big names from the field of music and dance and the celebrations will give the Capital the golden chance to witness the masters in action.The first day, 20 March will have Lakshay Mohan (Sitar) and Aayush Mohan (Sarod) and Tanmoy Bose (Drums of India). 21 March will have Ayesha Thatte (Vocal), Sanjeev and Ashwani Shankar (Shahnai) and Rama Vaidyanathan (Bharatanatyam). 22 March will play host to Radhika Samson (Odissi), Swarnima Gusain (Vocal) and Salil Bhatt (Satwik Veena). The final day, 23 March, will have Namrata Rai (Kathak), Maharajapuram Ramachandran (Carnatic Vocal) and Amita Dalal (Sitar).WHEN: 20–23 March, 6.00 pm onwards (Entry by invitation only, Invites available at the venue)WHERE: The Ravi Shankar Centre, 7, Rizal Marg, Chanakyapuri