Explore further Supernovae and similar high-energy events can accelerate protons and heavier atomic nuclei to enormous speeds, imparting a kinetic energy thousands of times greater than the mass of the particle itself. Many are much more powerful than anything our best particle accelerators can produce, so cosmic rays are of great interest to particle physicists as well as astronomers. The strongest (and rarest) cosmic rays can pack as much kinetic energy as a good punch in the jaw — no mean feat for a subatomic particle weighing 1027 times less than your fist!For all their scientific potential, cosmic rays cannot be identified with any specific source. Because atomic nuclei are charged particles, they can be deflected by the Milky Way’s magnetic field. While scientists have many ideas concerning the astronomical processes that can create cosmic rays, it has proven difficult to test these ideas.What’s more, most of the cosmic rays that meet the Earth never make it to the ground. Their annihilation in the atmosphere produces an “shower” of muons (heavy electrons, essentially), neutrinos, and other simple subatomic particles. Some of the byproducts can produce showers of their own, eventually dissipating most of the cosmic ray’s energy into the atmosphere. (The photograph shown here was taken from a baloon high in the atmosphere.) The high-energy muons, however, interact only rarely with matter and can slide through miles of atmosphere and bedrock before coming to a halt. Building a better μ-trapCosmic ray muons are elusive targets, and can’t be counted by watching the sky. Instead researchers must surround an enormous volume of transparent material with detectors, and hope to catch a small fraction of the passing particles inside. The Super-Kamiokande experiment, for example, is an underground tank containing 50,000 tons of water. Cosmic muons in particular have a distinctive signature. While they travel at speeds close to that of light, light is about 75% slower in water than in air. The muons therefore move faster than the light they emit, so the leading edges of the emitted waves pile up into a bright, cone-shaped pulse. The same phenomenon can be seen in the powerful crest that defines the wake of a speedboat, or heard in the boom of a supersonic jet or rocket. When a cosmic muon passes through, the photomultipliers trace out a perfect ellipse or hyperbola (a conic section) on the wall.Collecting over 200 million cosmic ray muons from five years of Super-Kamiokande data, researchers Gene Guillian, Yuichi Oyama, and other collaborators were able to reconstruct a full-sky map of the cosmic ray flux. Two features are readily apparent: an excess of cosmic rays in the direction of the constellation Taurus, and a deficit in the direction of Virgo. (The scale on the right is the ratio of local flux to average flux.) The excess and deficit are both detected with a very high confidence; the probability for each to have been produced by random fluctuations is less than one in a million. Their amplitudes are also roughly the same, and they are separated by an angle of about 130° on the sky. This odd angle seems to preclude the most obvious explanation, that Super-K is seeing the effect of the Earth’s motion with respect to an isotropic cosmic ray background. If such were the case, then the separation between the two features should be exactly 180°.Oyama and Guillian offer another possible explanation. The cosmic ray excess points into the denser regions of our spiral arm of the Milky Way galaxy, and the deficit is pointing roughly out of the galactic plane. Does this result prove that some of the cosmic rays come from nearby sources? “We have no idea about this,” responds Oyama, who goes on to explain that the entire theoretical community will want to debate the matter. Guillian’s paper, for example, mentions a competing hypothesis: that local structure in the galactic magnetic field may focus or defocus the cosmic ray flux in certain directions. These results provide an important clue to the origin of cosmic rays, and will certainly shed light on the question of how the galactic magnetic field influences their journey. “In 1987, Kamiokande started an astronomy beyond light.” Dr. Oyama explains, referring to the detection of supernova neutrinos mentioned above. “In 2005, Super-Kamiokande started an astronomy beyond neutral particles.”References:Yuichi Oyama, 2006, “Anisotropy of the Primary Cosmic Ray Flux in Super-Kamiokande” http://xxx.lanl.gov/astro-ph/0605020Gene Guillian et al., 2005, “Observation of the Anisotropy of 10 TeV Primary Cosmic Ray Nuclei Flux with the Super-Kamiokande-I Detector” http://xxx.lanl.gov/astro-ph/0508468The cosmic ray photograph was taken from the website “The Exploration of the Earth’s Magnetosphere” at URL http://www-spof.gsfc.nasa.gov/Education/index.htmlBy Ben Mathiesen, Copyright 2006 PhysOrg.com Cosmic rays, which are high-energy atomic nuclei driven by spectacular cosmic events, come to us from every direction on the sky. Most of them are destroyed high in the atmosphere, creating a shower of high-speed particles that penetrate sky and earth with ease. Surprising results from Japan’s Super-Kamiokande underground observatory have recently shown that the distribution of cosmic rays on the sky is not uniform, a useful clue to the nature of these cosmic voyagers. 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. How conspiracy theories followed man to the Moon Lining the walls of this tank are 11,200 photomultiplier tubes, sensitive instruments that amplify the faintest glimmer of light into a strong electrical current. If an interesting event occurs anywhere in the tank’s volume, the nature of the interaction can be reconstructed from the pattern of captured light on the walls. When supernova 1987a exploded in the Large Magellanic Cloud, for example, Super-Kamiokande captured a dozen neutrinos in two separate pulses from the dying star. Citation: Super-Kamiokande Finds Structure in the Cosmic Ray Sky (2006, May 15) retrieved 18 August 2019 from https://phys.org/news/2006-05-super-kamiokande-cosmic-ray-sky.html A full-sky map of the total cosmic ray muon flux received by Super-Kamiokande over a five-year period. The circular regions (distorted by the map projection) drawn in red and blue enclose the excess and deficit respectively. The color scale ranges from an excess of 0.5% to a deficit of -0.5%. A collision between a high-energy cosmic ray particle and an atom in a photographic emulsion, as viewed through a microscope. Credit: NASA, Dr. David P. Stern
Explore further Where ants go when nature calls The Ants In Space CSI-06 investigation looks at how an ant colony responds to the extreme environment of microgravity aboard the International Space Station to solve their collective need for resources. Data gathered from this study may help with algorithms for robotics on Earth. Credit: NASA Last summer, a team of researchers in the U.S. affiliated with several institutions across the country described experiments they were planning to conduct with ants by sending some to the International Space Station—they wanted to know how the ants would change their searching activities to compensate for the lack of gravity. Those experiments have been carried out and the team now reports that the ants showed a remarkable degree of adaptability and tenacity in carrying out their searching activities.Scientists still do not understand how ants band together as a unit to get work done—there is no central leader yet different ants fill different roles and all the things that need to happen to build and maintain a colony happen, most particularly, foraging, where ants check out new territory and then bring back food. Scientists know that the ants communicate by smelling antennae, or chemicals left on trails, but other than that, are baffled. The researchers on this new project were hoping watching ants deal with space conditions might help in understanding how they do what they do.The experiments consisted of having a group of ants start off in a box that served as a nest. At some point, a door would be opened allowing the ants access to new territory—they were filmed as they moved into the new territory and began searching. In watching the video, the researchers noted that the ants were far less efficient than ants in the exact same conditions back on Earth, they spent much more time simply trying to cling to walls, and quite often found themselves slipping and hanging in the air—oftentimes for several seconds, until they found something they could grab onto to bring them back to their task area—the end result was less territory searched or re-searched and more time taken to find resources.Thus far, it does not appear the ants in space experiment has yielded much else in the way of explaining how the ants know what to do and when, but, the team suggests, their ability to adapt to new surroundings and to continue searching might help other scientists looking to develop better computer algorithms for programming robots to do the same sorts of things. © 2015 Phys.org More information: Collective search by ants in microgravity, Front. Ecol. Evol., 30 March 2015. DOI: 10.3389/fevo.2015.00025AbstractThe problem of collective search is a tradeoff between searching thoroughly and covering as much area as possible. This tradeoff depends on the density of searchers. Solutions to the problem of collective search are currently of much interest in robotics and in the study of distributed algorithms, for example to design ways that without central control robots can use local information to perform search and rescue operations. Ant colonies operate without central control. Because they can perceive only local, mostly chemical and tactile cues, they must search collectively to find resources and to monitor the colony’s environment. Examining how ants in diverse environments solve the problem of collective search can elucidate how evolution has led to diverse forms of collective behavior. An experiment on the International Space Station in January 2014 examined how ants (Tetramorium caespitum) perform collective search in microgravity. In the ISS experiment, the ants explored a small arena in which a barrier was lowered to increase the area and thus lower ant density. In microgravity, relative to ground controls, ants explored the area less thoroughly and took more convoluted paths. It appears that the difficulty of holding on to the surface interfered with the ants’ ability to search collectively. Ants frequently lost contact with the surface, but showed a remarkable ability to regain contact with the surface. Citation: Ants in space find it tougher going than those on Earth (2015, April 1) retrieved 18 August 2019 from https://phys.org/news/2015-04-ants-space-tougher-earth.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only. (Phys.org)—The results of a study conducted to see how well ants carry out their search activities in space are in, and the team that sent them there has written and published the results in the journal Frontiers in Ecology and Evolution. They found that while the ants demonstrated a remarkable capacity to adapt to the weightlessness of space, they still found it much more difficult than ants performing the same sorts of activities back here on Earth.
Scanning electron microscope image of V. cholerae. Credit: public domain Journal information: Science Advances © 2016 Phys.org PausePlay% buffered00:0000:00UnmuteMuteDisable captionsEnable captionsSettingsCaptionsDisabledQuality0SpeedNormalCaptionsGo back to previous menuQualityGo back to previous menuSpeedGo back to previous menu0.5×0.75×Normal1.25×1.5×1.75×2×Exit fullscreenEnter fullscreen Citation: Study reveals how cholera’s two chromosomes communicate to coordinate replication (2016, April 25) retrieved 18 August 2019 from https://phys.org/news/2016-04-reveals-cholera-chromosomes-replication.html Explore further More information: M.-E. Val et al. A checkpoint control orchestrates the replication of the two chromosomes of Vibrio cholerae, Science Advances (2016). DOI: 10.1126/sciadv.1501914AbstractBacteria with multiple chromosomes represent up to 10% of all bacterial species. Unlike eukaryotes, these bacteria use chromosome-specific initiators for their replication. In all cases investigated, the machineries for secondary chromosome replication initiation are of plasmid origin. One of the important differences between plasmids and chromosomes is that the latter replicate during a defined period of the cell cycle, ensuring a single round of replication per cell. Vibrio cholerae carries two circular chromosomes, Chr1 and Chr2, which are replicated in a well-orchestrated manner with the cell cycle and coordinated in such a way that replication termination occurs at the same time. However, the mechanism coordinating this synchrony remains speculative. We investigated this mechanism and revealed that initiation of Chr2 replication is triggered by the replication of a 150-bp locus positioned on Chr1, called crtS. This crtS replication–mediated Chr2 replication initiation mechanism explains how the two chromosomes communicate to coordinate their replication. Our study reveals a new checkpoint control mechanism in bacteria, and highlights possible functional interactions mediated by contacts between two chromosomes, an unprecedented observation in bacteria. V. cholera has been studied extensively for some time as part of an ongoing process to either eliminate it as a threat to people, or to treat infections. As part of that effort, scientists have found that each bacterium has two chromosomes, both of which need to split prior to the cell splitting as part of its life cycle. Prior research has shown that the chromosomes split at the same time, which has suggested a means of communications between the two. In this new effort, the researchers have identified that means of communication and the parts of the chromosomes that are involved in the process.The two chromosomes in each cell are called chr1 and chr2. Chr1 is a lot longer than chr2 and is the chromosome that initiates the entire division process, the team found, when a DnaA molecule binds to a part of the chromosome called ori2 leading to the replication process in chr1, along a circular path. When that path crosses a point the researchers have called crtS, a molecule called RctB is activated which makes its way to chr2 causing it to begins its replication process. The two processes then finish at very nearly the same time—just prior to the complete cell dividing—due to the physical proximity of the two chromosomes and the location of the crtS on chr1.The team then deleted the crtS region in some of the bacteria and found that doing so caused problems with growth and DNA damage. They also allowed one group of the mutant bacteria to multiply over 200 generations to learn more about how the bacteria might compensate for the loss of crtS and discovered that that the mutations led only to mutations in RctB, which the team claims, shows that activation by RctB is a crucial part of the process. (Phys.org)—A team of researchers from France and Denmark, working at Institut Pasteur, in Paris has found the mechanism that is involved that allows dual chromosomes in Vibrio cholerae cells to split at the same time as part of replication. In their paper published in the journal Science Advances, the team describes how they closely studied cell replication in V. cholerae, the bacteria that cause cholera, and then verified their understanding of how chromosome division was occurring by disabling different parts involved in the process. Researchers discover novel role of TBK1 protein in cell division Play An animation presenting the model for replication checkpoint control in Vibrio cholerae. Credit: Val Marie-Eve 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.
© 2018 Medical Xpress More information: Crystal D. McClure et al. US particulate matter air quality improves except in wildfire-prone areas, Proceedings of the National Academy of Sciences (2018). DOI: 10.1073/pnas.1804353115AbstractUsing data from rural monitoring sites across the contiguous United States, we evaluated fine particulate matter (PM2.5) trends for 1988–2016. We calculate trends in the policy-relevant 98th quantile of PM2.5 using Quantile Regression. We use Kriging and Gaussian Geostatistical Simulations to interpolate trends between observed data points. Overall, we found positive trends in 98th quantile PM2.5 at sites within the Northwest United States (average 0.21 ± 0.12 µg·m−3·y−1; ±95% confidence interval). This was in contrast with sites throughout the rest of country, which showed a negative trend in 98th quantile PM2.5, likely due to reductions in anthropogenic emissions (average −0.66 ± 0.10 µg·m−3·y−1). The positive trend in 98th quantile PM2.5 is due to wildfire activity and was supported by positive trends in total carbon and no trend in sulfate across the Northwest. We also evaluated daily moderate resolution imaging spectroradiometer (MODIS) aerosol optical depth (AOD) for 2002–2017 throughout the United States to compare with ground-based trends. For both Interagency Monitoring of Protected Visual Environments (IMPROVE) PM2.5 and MODIS AOD datasets, we found positive 98th quantile trends in the Northwest (1.77 ± 0.68% and 2.12 ± 0.81% per year, respectively) through 2016. The trend in Northwest AOD is even greater if data for the high-fire year of 2017 are included. These results indicate a decrease in PM2.5 over most of the country but a positive trend in the 98th quantile PM2.5 across the Northwest due to wildfires. Journal information: Proceedings of the National Academy of Sciences Citation: Increase in wildfires causing bad air days in US Northwest to get worse over the past 28 years (2018, July 17) retrieved 18 August 2019 from https://phys.org/news/2018-07-wildfires-bad-air-days-northwest.html Over the past quarter-century, wildfires (unplanned fires burning in forests or other areas) in many parts of the western United States have become larger and longer-lasting than they were in earlier years. Many environmental scientists have suggested this is due to global warming. Prior research has shown that such fires carry fine particulate matter into the air, and that many people can be harmed by breathing such particles. Those with lung conditions such as COPD or asthma, for example, can suffer problems when exposed to such particles, as can senior citizens and children. In this new effort, McClure and Jaffe looked into the possible impacts of bigger and longer-burning wildfires on people living in impacted areas.They obtained data from 100 rural air quality monitoring sites from across the country and sifted through the data, collecting information only on particles that were smaller than 2.5 micrometers. They entered the data into a mapping application that displayed levels of such particulates across the continental U.S. Next, they set filters to show changes in levels of the fine particulates over the years 1988 to 2016 for only the worst air quality days. Doing so showed that the northwest part of the country has experienced more bad days over the past 28 years, and those bad days have been worsening. In sharp contrast, they found that the rest of the United States experienced better air quality over the same time period. The researchers note that even people who are not normally at risk from wildfire particulates can be harmed if they are exposed to them on a regular basis. And sometimes, levels can be extreme, such as when a fire burns for a long time near a community. 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.
Kolkata: Left Front has called a 6-hour Bangla bandh on April 13, to protest against the ‘reign of terror unleashed by Trinamool Congress’ over the filing of nominations by Opposition candidates. Left Front chairman Biman Bose said there has been unprecedented violence over filing of nominations throughout the state.He said the bandh will start at 6 am and end at 12 noon. The CBSE candidates who will have exam on that day, will be exempted.It may be mentioned that the Opposition parties have fielded over 68,000 candidates in Gram Panchayat, Panchayat Samity and Zilla Parishad. Of these, Left Front has fielded 24,768 candidates.
Kolkata: The joint initiative of the local councillor and a private media and management institute in the city, has led to the unveiling of a unique library at Bhowanipore in South Kolkata, where the reader is free to take books home free of cost. The only condition is that he/she has to return the book after they finish reading it.”The street library has been set up on the wall of Vidyanjali High School at the crossing of Allenby Road and Dr Rajendra Road. Racks have been attached to the wall where the books are kept and a shade has been made over the racks to prevent the books from getting soaked during the rain. There is no librarian or guard to see who are taking the books. People are free to take the books round the clock, any time they wish,” councillor of ward 70 Ashim Basu said. Also Read – Heavy rain hits traffic, flightsWhen asked about the possibility of theft as there is nobody to keep a watch on the ‘street library’, Basu said, “Believe me, a majority of the people who have taken books have returned them. A number of people who have taken books have come back with more books to add to the collection of the library. The library has started on May 5 and already, fifteen days have passed. There are a number of vagabonds who sleep on the footpath in the adjacent area, but there has been no theft,” Basu added. Also Read – Speeding Jaguar crashes into Merc, 2 B’deshi bystanders killedThe library presently has 400 books, mainly in the form of story books, comics and novels in languages like English, Bengali, Hindi and Gujrati.Principal of Vidyanjali High School Saswati Dutta, who has also contributed to the setting up of the library by gifting its wall, said “Free libraries are a fascinating platform to connect, share and exchange ideas, books and network with people.”Basu, however, said that as the stock of books increases, he will install CCTVs to keep a track on the records.
After masterminding Rajasthan Royals’ nine-run win over Kolkata Knight Riders with an all-round show to take them into the
Kolkata: Train services in Howrah division was affected for more than five hours, after the engine and a coach of an empty Howrah-Titlagarh Ispat Express derailed while entering Howrah Station on Thursday morning.According to sources, the Ispat Express was entering platform number 23 of Howrah Station from the car-shed, when the train engine and an adjacent coach derailed at around 6.00 am. Entry and departure of trains from platform numbers 21, 22 & 23 of Howrah Station new complex was hit. Also Read – Rain batters Kolkata, cripples normal life”No one was injured in the accident as the empty train was coming to the station from the car-shed for commencing its journey to Titlagarh,” a South Eastern Railway (SER) spokesperson said.A number of trains under the SER were rescheduled and short terminated and a handful of local trains were cancelled as a result of the mishap.The Howrah-Puri Dhauli Express that was scheduled to leave Howrah at 6.00 am, was rescheduled to 9.30 am, while the Howrah-Titlagarh Ispat Express that was scheduled to depart at 6.55 am, was rescheduled to 10.00 am. Also Read – Speeding Jaguar crashes into Mercedes car in Kolkata, 2 pedestrians killedThe trains that were short terminated were LTT-Howrah Jnaneswari Express, Mumbai-Howrah Mail, Puri-Howrah Sri Jagannath Express, Jagdalpur-Howrah Express, Purulia-Howrah Rupasi Bangla Express and Digha-Howrah Kandari Express.Two local trains were also short terminated at Santragachi, while three up and down Panskura local trains were cancelled.Santragachi-Jabalpur Special was rescheduled to leave Santragachi at 10.40 pm instead of 8.40 pm, due to late running of link train.”The work for rerailment and restoration that begun soon after the incident, was completed at 11.35 am in the morning,” a spokesperson of Eastern Railway said. Normal train service started from Howrah New Complex after 12 noon.
Indian Railway Catering and Tourism Corporation Limited is gearing up to launch two premier train services that will unveil the charm of the country’s sprawling deserts and eclectic heritage before its travellers. Both semi-luxury trains will depart from New Delhi with an array of deluxe facilities across its five days of round trip dotted with sightseeing facilities, an IRCTC release said here on Tuesday.”Desert Circuit” will cover Rajasthan’s famed cities of Jaisalmer and Jaipur, while “Heritage Circuit” will take the passengers to Varanasi, Khajuraho and Agra. Operated by IRCTC, the ‘mini ratna’ PSU of the Railways, the two trains will run eight trips individually till summer sets in upcountry by next April, it said. Desert Circuit will begin service from mid-December 2015 and wind up on April 21, while Heritage Circuit will commence on December 20. Its last trip will start on April 24. Also Read – Punjab & Sind Bank cuts MCLR by up to 20 basis points”Now that the tourist season is on, we expect good occupancy. The tariff for the journey is competitive as well as all-inclusive,” IRCTC Chairman and Managing Director Dr A K Manocha said. The package prices of Desert Circuit are: Rs 36,900, Rs 33,900, Rs 32,900 (first AC single, double and triple occupancy, respectively), Rs 28,025, Rs 25025, Rs 24,525 (second AC) and Rs 24,125, Rs 21,125, Rs 20,625 (third AC), the statement said. As for Heritage Circuit, the rates will be Rs 35,900, Rs 32,900, Rs 31,900 (first AC single, double and triple occupancy), Rs 26,200, Rs 23,200, Rs 22,700 (second AC) and Rs 21,790, Rs 18,790, Rs 18, 290 (third AC), it said. Also Read – ‘The great gold bull market has begun’The package, which includes intercity transfers, also features stay in three-star hotels, all meals (breakfast, lunch and dinner), sightseeing, local transfers by AC deluxe vehicles, entrances at the monuments, service of English/Hindi speaking guide, travel insurance, 24×7 security and CCTV surveillance on board the train, besides hygienic kitchen-car facility, medical facility, transport by AC vehicles and wi-fi internet service.The Jaisalmer stop of the Desert Circuit will cover the city Fort, sand dunes, Gadisagar lake and Palwaon Ki Haveli. At Jaipur, the sights shown will be City Palace, Jantar Mantar observatory, Chokhi Dhani, Amer Fort and Hawa Mahal, it said. The Heritage Circuit will, at Varanasi, take passengers to Sarnath, besides a boat ride on the Ganges and experiencing the dusk-time ‘aarti’ ceremony.