пятница, 25 января 2019 г.

A Problem Shared When studying rare disorders, investigating…


A Problem Shared


When studying rare disorders, investigating similar, more common conditions in another species can provide useful insight. In the case of Robinow syndrome, which causes abnormal growth and spinal deformities, recent research suggests that some of man’s best friends could shed light on the problem. Dog breeds like bulldogs are adored for their wide heads, short muzzles and diminutive curly tails, but these characteristics are often associated with health problems. To examine the genetic basis of these traits, scientists sequenced the genomes of 100 dogs, including French bulldog Moxie (pictured), eventually identifying a key mutation associated with these breeds. The affected gene, named DVL2, is closely related to genes DVL1 and DVL3, which have already been linked to Robinow syndrome in humans. Researchers found that the bulldog version of DVL2 disrupted a major signalling pathway, known as Wnt signalling, suggesting that processes affecting Wnt signalling may also underpin Robinow syndrome.


Written by Emmanuelle Briolat



You can also follow BPoD on Instagram, Twitter and Facebook


Archive link


Bird beaks did not adapt to food types as previously thought

A study, led by the University of Bristol, has shed some new light on how the beaks of birds have adapted over time.











Bird beaks did not adapt to food types as previously thought
Pictures depicting three different tasks (display, preening and feeding) the Atlantic puffin (Fratercula
arctica), one of the176 bird species studied in the article, accomplishes with its beak
 [Credit: Sergio Martínez-Nebreda & Paula Medina-García]

The observation that Galapagos finch species possessed different beak shapes to obtain different foods was central to the theory of evolution by natural selection, and it has been assumed that this form-function relationship holds true across all species of bird.


However, a new study published in the journal Evolution suggests the beaks of birds are not as adapted to the food types they feed on as it is generally believed.


An international team of scientists from the United Kingdom, Spain and the US used computational and mathematical techniques to better understand the connection between beak shapes and functions in living birds.


By measuring beak shape in a wide range of modern bird species from museum collections and looking at information about how the beak is used by different species to eat different foods, the team were able to assess the link between beak shape and feeding behaviour.


Professor Emily Rayfield, from the University of Bristol’s School of Earth Sciences, and senior author of the study, said: “This is, to our knowledge, the first approach to test a long-standing principle in biology: that the beak shape and function of birds is tightly linked to their feeding ecologies.”


Guillermo Navalón, lead author of the study and a final year PhD student at Bristol’s School of Earth Sciences, added: “The connection between beak shapes and feeding ecology in birds was much weaker and more complex than we expected and that while there is definitely a relationship there, many species with similarly shaped beaks forage in entirely different ways and on entirely different kinds of food.


“This is something that has been shown in other animal groups, but in birds this relationship was always assumed to be stronger.”


Co-author, Dr Jesús Marugán-Lobón from Universidad Autónoma de Madrid, said: “These results only made sense when you realise birds use the beak for literally everything!


“Therefore, also makes sense they evolved a versatile tool not just for getting food, but also to accomplish many other tasks.”


The study is part of a larger research effort by the team in collaboration with researchers from other universities across Europe and the US to better understand the main drivers of the evolution of the skull in birds.


Dr Jen Bright, co-author from the University of South Florida, said: “We have seen similar results before in birds of prey, but this is the first time we studied the link between beak shape and ecology across all bird groups.


“We looked at a huge range of beak shapes and feeding ecologies: hummingbirds, eagles, parrots, puffins, flamingos, pretty much every beak you can think of.”


Guillermo Navalón added: “These results have important implications for the study of fossil birds.


“We have to be careful about inferring ecology in ancient birds, which we often assume based solely on the shape of the beak.


“Really, we’re just starting to scratch the surface, and a lot more research is needed to fully understand the drivers behind beak shape evolution.”


Source: University of Bristol [January 22, 2019]



TANN



Archive


Researcher contributes piece to the puzzle of baleen whales’ evolution

An Otago researcher has added another piece to the puzzle of the evolution of modern baleen whales with a world-first study examining the teeth and enamel of baleen whales’ ancestors.











Researcher contributes piece to the puzzle of baleen whales' evolution
Tooth from a 35 million-year-old fossil whale analyzed by Dr. Carolina Loch as part of her research
[Credit: Dr. Carolina Loch]

Modern baleen whales have no teeth when adults, instead they use large keratin plates called baleen to filter prey from large volumes of seawater. However, millions of years ago their ancestors had teeth as most mammals do.


Lead author of the research just published in the Journal of Mammalian Evolution, Dr Carolina Loch from the Faculty of Dentistry, explains scientists are still trying to understand how and why this process happened. The research she carried out together with colleagues from the National Scientific and Technical Research Council in Argentina, CONICET, and the Swedish Museum of Natural History has provided more information.


They studied details of the inside structure of the teeth of two fossil whales from around 35 million years ago. These teeth were collected in Antarctica by the Argentinian and Swedish study co-authors Monica Buono and Thomas Mörs. Because teeth are naturally heavily mineralised, they preserve well in the fossil record and can provide clues of how extinct animals lived.


“We looked at how the enamel — the hard outside cover of teeth — and dentine, the core ‘living’ part, were structured and how similar or different they were from teeth of living whales, other fossil whales and other mammals,” Dr Loch explains.


“Both fossil whales we analysed (basilosaurid and fossil mysticete) had a complex enamel layer with biomechanical structures that suggest they were capable of heavy shearing and processing of their prey,” she says.


The enamel layer of the fossil mysticete they studied was the thickest enamel layer ever observed among cetaceans, both extinct and living.


“This is quite puzzling; baleen whales’ ancestors had teeth with complex and thick enamel, but millions of years later the teeth were ‘lost’ and replaced with large keratin plates called baleen,” Dr Loch says.


Because of the rarity of the material examined, Dr Loch says it is quite significant that the researchers were able to study them.


“Scanning electron microscopy is considered a ‘destructive’ type of analysis because the specimens need to be cut, polished and gold coated. It is fantastic that some museum curators are open to facilitate this kind of research and allow us to unravel new and important information.”


The study of the structure of the enamel and dentine of animals, both fossil and living, is a strength of Dr Loch’s research programme. Last year, the University of Otago highlighted another of her projects examining bottlenose dolphin teeth to help understand coastal contamination.


She hopes to continue studying teeth to help learn about how past animals lived and interacted with the environment, showing the breadth of the multidisciplinary research carried out in the University’s Faculty of Dentistry.


“As more fossil whales and other mammals are discovered and described, there is more material to be studied. I will continue working in partnership with colleagues overseas and in New Zealand in order to add small pieces to this puzzle — one tooth at a time.”


Source: University of Otago [January 22, 2019]



TANN



Archive


Human mutation rate has slowed recently

Researchers from Aarhus University, Denmark, and Copenhagen Zoo have discovered that the human mutation rate is significantly slower than for our closest primate relatives. The new knowledge may be important for estimates of when the common ancestor for humans and chimpanzees lived — and for conservation of large primates in the wild.











Human mutation rate has slowed recently
The photograph shows Carl, an alpha-male chimpanzee at Copenhagen Zoo, and one
of the participants in the study [Credit: Copenhagen Zoo, David Trood]

Over the past million years or so, the human mutation rate has been slowing down so that significantly fewer new mutations now occur in humans per year than in our closest primate relatives. This is the conclusion of researchers from Aarhus University, Denmark, and Copenhagen Zoo in a new study in which they have found new mutations in chimpanzees, gorillas and orangutans, and compared these with corresponding studies in humans.


Using whole-genome sequencing of families, it is possible to discover new mutations by finding genetic variants that are only present in the child and not in the parents.


“Over the past six years, several large studies have done this for humans, so we have extensive knowledge about the number of new mutations that occur in humans every year. Until now, however, there have not been any good estimates of mutation rates in our closest primate relatives,” says Søren Besenbacher from Aarhus University.


The study has looked at ten families with father, mother and offspring: seven chimpanzee-families, two gorilla families and one orangutan family. In all the families, researchers found more mutations than would be expected on the basis of the number of mutations that would typically arise in human families with parents of similar age. This means that the annual mutation rate is now about one-third lower in humans than in apes.


Time of speciation fits better with fossil evidence


The higher rates in apes have an impact on the length of time estimated to have passed since the common ancestor of humans and chimpanzees lived. This is because a higher mutation rate means that the number of genetic differences between humans and chimpanzees will accumulate over a shorter period.


If the new mutation rates for apes are applied, the researchers estimate that the species formation (speciation) that separated humans from chimpanzees took place around 6.6 million years ago. If the mutation rate for humans is applied, speciation should have been around 10 million years ago.


“The times of speciation we can now calculate on the basis of the new rate fit in much better with the speciation times we would expect from the dated fossils of human ancestors that we know of,” explains Mikkel Heide Schierup from Aarhus University.


The reduction in the human mutation rate demonstrated in the study could also mean that we have to move our estimate for the split between Neanderthals and humans closer to the present.


Furthermore, the results could have an impact on conservation of the great apes. Christina Hvilsom from Copenhagen Zoo explains:


“All species of great apes are endangered in the wild. With more accurate dating of how populations have changed in relation to climate over time, we can get a picture of how species could cope with future climate change.”


The study “Direct estimation of mutations in great apes reconciles phylogenetic dating” has been published in Nature Ecology and Evolution and is a collaboration between researchers from Aarhus University, Copenhagen Zoo and Universitat Pompeu Fabra in Barcelona.


Author: Christina Troelsen | Source: Aarhus University [January 22, 2019]



TANN



Archive


‘Revealing Greater Cahokia’ details research on ancient North American...

With a population between 10,000 and 30,000 in its heyday (A.D. 1050-1200) and a sprawling assortment of homes, storage buildings, temples, cemeteries, mounds and other monuments in and around what is now St. Louis and East St. Louis, Illinois, the ancient Native American city known as Greater Cahokia was the first experiment in urban living in what is now known as the United States.











'Revealing Greater Cahokia' details research on ancient North American metropolis
Archaeologists painstakingly dissected the wealth of artifacts left behind at Greater Cahokia and, in the process, resurrected
something of the history, culture and religion of those who built and maintained the city. A new book offers an in-depth
picture of what they found, and learned, from the vast collection of artifacts [Credit: L. Brian Stauffer]

A new book, “Revealing Greater Cahokia, North America’s First Native City,” offers the most complete picture yet of a decade of archaeological research on a little-known part of the larger city and its precincts in East St. Louis. The more famous part of the city is preserved as Cahokia Mounds Historic Site, which had more than 100 earthen monuments, a 50-acre plaza, neighborhoods and a central pyramid, the massive Monk’s Mound, which, according to the authors, was “the largest earthen structure in the New World.”
“There’s never been an excavation as extensive as our dig into the Cahokia precinct in East St. Louis,” said archaeologist Thomas Emerson, the former director of the Illinois State Archaeological Survey, a Cahokia researcher and one of three editors of the 537-page volume. “And there’s never been a book with as many new discoveries about Cahokia as this one.”











'Revealing Greater Cahokia' details research on ancient North American metropolis
The new book details the immense archaeological effort to excavate and interpret artifacts
associated with Greater Cahokia, an ancient city on the Mississippi River
[Credit: Illinois Archaeological Society]

Cahokia rose abruptly starting in A.D. 1050, and was abandoned almost as abruptly 250 years later. Its failure—which other studies revealed came during a period of climate change and regional conflict—offers more of a mystery than its origins.
“Certainly, a warmer medieval-period climate was behind the early growth of Cahokia, as was the adoption of maize or corn agriculture and the spread of a new Native American religion,” said Timothy Pauketat, a professor of anthropology and of medieval studies at the University of Illinois and a co-interim director of ISAS. “People immigrated to this new city from far and wide, probably perceiving it to have been blessed by spiritual forces. There’s no better place in North America for a civilization to arise.”











'Revealing Greater Cahokia' details research on ancient North American metropolis
Early illustration of Downtown Cahokia (bottom), to scale, and a map of this location (top)
in the context of Greater Cahokia [Credit: Illinois State Archaeological Survey]

Between its origin and abandonment, Cahokia was transformed by human activity. Its people constructed several types of mounds, which had practical as well as ceremonial functions. They also built temples and homes with wooden posts and thatch roofs and walls.











'Revealing Greater Cahokia' details research on ancient North American metropolis
Archaeologists link these objects found at Cahokia to a 12th-century world renewal and fertility cult
[Credit: Illinois Archaeological Society: ‘Revealing Greater Cahokia’]

They carved figurines depicting a female goddess and made ceramic vessels with special types of containers for food and ritual. They fashioned stone, flint and copper tools. They imported ocean shells, shark teeth and caffeine-rich tea leaves from distant waters and lands. They buried their dead in large group cemeteries and in ceremonial mounds.
“Greater Cahokia” offers insights into the daily lives, rituals, health issues and religious practices of the ancient people who built it. For example:


– Strontium analyses of the teeth of dozens of individuals buried in Cahokia reveal that, while most citizens grew up in the immediate vicinity, at least 20 percent were immigrants from elsewhere.


– Agricultural tools and animal bones reveal that the people ate a wide variety of foods, some of which they hunted and gathered, but much of which they grew in their fields.


– A study of plant residues found inside decorated pottery beakers that look like large coffee mugs found evidence that the beakers were used to consume a type of holly tea, called black drink, used as a stimulant by Native peoples elsewhere in the Americas.


– Objects made from materials not available in the immediate vicinity make it clear that visitors brought gifts to Cahokia when they came to experience the city’s many wonders.


– Numerous carved likenesses of humans and animals uncovered at Cahokia open a window on the spiritual beliefs of their makers.


– The book also details the history of the land and landscape and processes that destroyed—and in some cases preserved—parts of the site when European newcomers built their towns, highways and farms on top of the ancient city.


Author: Diana Yates | Source: University of Illinois at Urbana-Champaign [January 22, 2019]



TANN



Archive


A surprisingly early replacement of Neanderthals by modern humans in southern Spain

A new study of Bajondillo Cave (Málaga) by a team of researchers based in Spain, Japan and the UK, coordinated from the Universidad de Sevilla, reveals that modern humans replaced Neanderthals at this site approximately 44,000 years ago. The research, to be published in Nature Ecology and Evolution, shows that the replacement of Neanderthals by modern humans in southern Iberia began early, rather than late, in comparison to the rest of Western Europe.











A surprisingly early replacement of Neanderthals by modern humans in southern Spain
Bajondillo Cave and Malága Bay (Spain) at the end of the 1950s. Foreground images show Neanderthal
(La Chapelle-aux-Saints, France, left) and early Modern Human (from Abri Cro-Magnon, France, right)
skulls. Left lithic tool corresponds to Mousterian technology, and right Aurignacian, both recovered
at Bajondillo Cave [Credit: University of Seville]

Western Europe is a key area for understanding the timing of the replacement of Neanderthals by early modern humans (AMH). Typically in Western Europe, late Neanderthals are associated with stone tools belonging to Mousterian industries (named after the Neanderthal site of Le Moustier in France), while the earliest modern humans are associated with succeeding Aurignacian industries (named after the French site of Aurignac).
The final replacement of Neanderthals by AMH in western Europe is usually dated to around 39,000 years ago. However, it’s claimed that the southern Iberian region documents the late survival of the Mousterian, and therefore Neanderthals, to about 32,000 years ago, with no evidence for the early Aurignacian found elsewhere in Europe.


This new dating study of Bajondillo Cave, instead calibrates the replacement of Mousterian industries by Aurignacian ones there to between ~45-43,000 years ago, raising questions about the late survival of Neanderthals in southern Iberia. Further research is necessary to determine whether the new Bajondillo dating indicates an earlier replacement of Neanderthals across the whole of southern Iberia, or in fact, an altogether more complex scenario of co-existence over several millennia.











A surprisingly early replacement of Neanderthals by modern humans in southern Spain
Selected archaeological sites in Western Europe with Aurignacian industries actually or potentially older than 42,000 years,
 including Bajondillo Cave (Spain). Orange arrows indicate potential expansion routes across Europe at low sea level.
Images on the left show a Neanderthal skull (La Chapelle-aux-Saints, France) and a Mousterian tool recovered at
Bajondillo Cave. On the right the images show a Modern Human skull (Abri-Cro-Magnon, France) and
an Aurignacian tool recovered at Bajondillo Cave [Credit: University of Seville]

Co-author Jimenez-Espejo explains that the takeover by modern humans at the site at Bajondillo was not associated with a Heinrich (severe cooling) event, “Heinrich events represent the harshest and most variable climate conditions in Western Europe at the millennial scale, but at least in this Mediterranean coastal region, they did not control the Mousterian to Aurignacian transition.”


This research also highlights coastal corridors as the favoured routes for early AMH.


Professor Chris Stringer, Research Leader at the Natural History Museum and co-author of the study, said ‘Finding such an early Aurignacian from a cave so close to the sea adds to speculation that the Mediterranean coast could have been used by modern humans dispersing into Europe. This dating also fits with growing evidence that Homo sapiens had already spread rapidly across much of Eurasia more than 40,000 years ago’.


Considering the importance of coastal regions, co-author Arturo Morales-Muñiz suggested that the Bajondillo evidence also revives the idea that the Strait of Gibraltar could have been a potential dispersal route for early modern humans out of Africa.


Source: University of Seville [January 22, 2019]



TANN



Archive


Results of 2018 Tremithos Neolithic Survey

The Department of Antiquities of the Republic of Cyprus has announced that the Tremithos Neolithic Survey under the direction of Dr Sarah Stewart (Trent University Archaeological Research Centre) completed in May 2018 the surface survey of the Tremithos River Valley. The pedestrian survey focused on the area along the coast east and west of the Tremithos River Delta and north of the Kiti Dam to the Larnaca-Limassol Highway. All diagnostic finds were catalogued and photographed and submitted to the Larnaka District Museum.











Results of 2018 Tremithos Neolithic Survey
Credit: Department of Antiquities, Republic of Cyprus

A pedestrian surface survey of the coastal region from just east of the Pouzis River, west through the Tremithos delta, and east of the delta towards Pervolia, just west of Cape Kiti was undertaken. The beach floor, any associated sections and the terraces above the beach were examined. Numerous chert nodules, cores and flakes, often water worn, and manufactured from a wide variety of chert raw materials were found.  On the terraces above the beach, the fields were generally stubble wheat fields cultivated with no-till plowing, from which early material is rarely moved to the surface. Thus, it is increasingly difficult to find earlier prehistoric sites through pedestrian survey in tilled fields. The fact that relatively fresh lithics were found in the area where the terrace meets the beach, suggests that there is in situ cultural material below the surface. The best potential for finding these sites will be through test excavations.
The survey area with the highest potential for in-situ early archaeological material is located just east of the promontory at Limnes, with high potential for both Roman and Epipalaeolithic material, the latter including two microlithic multi-directional cores and numerous retouched flakes from a variety of chert. This is the most promising location along this coastal region for a potential Epipalaeolithic site, based on the recovered lithics and the fact that there is evidence of a small stream that would have flowed into the sea. The stream is currently buried under approximately one meter of well-developed soil at the stream outlet, which is marked by water worn cobbles.











Results of 2018 Tremithos Neolithic Survey
Location map of the Tremithos (T.) drainage basin. D.: Dhiarizos catchment; V.: Vassilikos catchment; G. or mid-Hol.: Gialias catchment configuration during early to mid-Holocene (after Devillers, 2005). The white stars show the
location of major archaeological sites mentioned in this paper (Erimi, Sotira, Tenta and Khirokitia)
[Credit: M. Ghilardi et al. Environmental Archaeology, 2014]

Other areas along the coast with prehistoric potential include the Careta Beach, located about half way between the Limnes promontory and the Tremithos River mouth. Clear stratigraphy was identified in the beach sections which included a series of palaeosols, with the upper the primary artifact bearing deposit with a quantity of pottery (Roman) and lithics. There was one small stream outlet that is either contemporary with, or cuts into, the artifact bearing strata. These sections are associated with stubble wheat fields in the terraces above, and thus have a high probability for in situ archaeological material.


On the east bank of the Tremithos River mouth early diagnostic material was found during the 2015 surface survey. Unfortunately this area is heavily disturbed by the recent road construction and soil levelling and may represent just a small remnant of the original eastern bank of a Tremithos meander. No additional potentially early material was found.


The east terraces above the banks of the Pouzis River between the sea and the highway, are under wheat cultivation, but with a combination of stubble no till fields and directly adjacent deeply tilled zones in which several chert cores and numerous retouched flakes with a distinctive Epipalaeolithic typology were located.


Very little archaeological material in the area between the Kiti Dam and the Larnaca to Limassol highway was found. These finds were isolated to some undiagnostic ceramic sherds (mostly apparently modern) and a few isolated lithic finds, again mostly undiagnostic, and probably from the Dhoukani threshing sledge industry. This area of the Tremithos, north of the dam, would be subject to flooding, alluvial deposition and erosion and most early material would likely now be deeply buried or washed downstream.


Source: Department of Antiquities, Republic of Cyprus [January 23, 2019]



TANN



Archive


2019 January 25 Moon Struck Image Credit & Copyright: …


2019 January 25


Moon Struck
Image Credit & Copyright: Petr Horálek


Explanation: Craters produced by ancient impacts on the airless Moon have long been a familiar sight. But only since the 1990s have observers began to regularly record and study optical flashes on the lunar surface, likely explosions resulting from impacting meteoroids. Of course, the flashes are difficult to see against a bright, sunlit lunar surface. But during the January 21 total eclipse many imagers serendipitously captured a meteoroid impact flash against the dim red Moon. Found while examining images taken shortly before the total eclipse phase began, the flash is indicated in the inset above, near the Moon’s darkened western limb. Estimates based on the flash duration recorded by the Moon Impact Detection and Analysis System (MIDAS) telescopes in southern Spain indicate the impactor’s mass was about 10 kilograms and created a crater between seven and ten meters in diameter.


∞ Source: apod.nasa.gov/apod/ap190125.html


NASA’s Opportunity Rover Logs 15 Years on Mars


NASA – Mars Exploration Rover B (MER-B) patch.


Jan. 24, 2019



Mars Exploration Rover (MER). Image Credits: NASA/JPL/Cornell University

NASA’s Opportunity rover begins its 16th year on the surface of Mars today. The rover landed in a region of the Red Planet called Meridiani Planum on Jan. 24, 2004, sending its first signal back to Earth from the surface at 9:05 p.m. PST (Jan. 25, 2004, at 12:05 a.m. EST). The golf-cart-sized rover was designed to travel 1,100 yards (1,006 meters) and operate on the Red Planet for 90 Martian days (sols). It has traveled over 28 miles (45 kilometers) and logged its 5,000th Martian day (or sol) back in February of 2018.


“Fifteen years on the surface of Mars is testament not only to a magnificent machine of exploration but the dedicated and talented team behind it that has allowed us to expand our discovery space of the Red Planet,” said John Callas, project manager for Opportunity at NASA’s Jet Propulsion Laboratory in Pasadena, California. “However, this anniversary cannot help but be a little bittersweet as at present we don’t know the rover’s status. We are doing everything in our power to communicate with Opportunity, but as time goes on, the probability of a successful contact with the rover continues to diminish.”


Opportunity’s last communication with Earth was received June 10, 2018, as a planet-wide dust storm blanketed the solar-powered rover’s location on the western rim of Perseverance Valley, eventually blocking out so much sunlight that the rover could no longer charge its batteries. Although the storm eventually abated and the skies over Perseverance cleared, the rover has not communicated with Earth since then. However, Opportunity’s mission continues, in a phase where mission engineers at JPL are sending commands to as well as listening for signals from the rover. If engineers hear from the rover, they could attempt a recovery.


Opportunity and its twin rover, Spirit, launched from Cape Canaveral, Florida, in 2003. Spirit landed on Mars in 2004, and its mission ended in 2011.


For more information about Opportunity and the Mars Exploration Rover program, visit: https://mars.nasa.gov/mer/home/index.html


Mars Exploration Rovers (Spirit and Opportunity): https://www.nasa.gov/mission_pages/mer/index.html


Image (mentioned), Text, Credits: NASA/Tony Greicius/JPL/DC Agle.


Best regards, Orbiter.chArchive link


ISRO – PSLV-C44 launches Microsat-R and Kalamsat


ISRO – Indian Space Research Organisation logo.


Jan. 24, 2019



PSLV-C44 launches Microsat-R and Kalamsat

PSLV-C44 successfully launched Microsat-R on January 24, 2019 at 23:37 hrs (IST)  from the First Launch Pad of Satish Dhawan Space Centre SHAR, Sriharikota. Microsat-R, an imaging satellite was injected into Sun Synchronous Polar orbit.



PSLV-C44 launches Microsat-R and Kalamsat

For ISRO’s PSLV-C44 mission, a Polar Satellite Launch Vehicle (PSLV) in “DL” configuration launched Microsat-R, an imaging satellite, and Kalamsat, a student payload, from the First Launch Pad (FLP) of Satish Dhawan Space Centre (SDSC) SHAR, Sriharikota, on 24 January 2019, at 18:08 UTC (23:38 IST). PSLV-C44 is the first mission of PSLV-DL, a new variant of PSLV with 2 strap-on boosters.



Kalamsat

India’s Polar Satellite Launch Vehicle (PSLV), designated PSLV-C44, launches the Microsat-R imaging satellite and the Kalamsat student payload into low Earth orbit. ISRO will debut a new version of the PSLV, named the PSLV-DL, with two strap-on solid rocket boosters.



Kalamsat student developper team

The fourth stage of the rocket carries the battery-powered Kalamsat student-built payload to demonstrate the use of the PSLV upper stage as a long-lived experiment platform.



PSLV-C44 is the 46th flight of India’s Polar Satellite Launch Vehicle (PSLV) and the first flight of PSLV-DL (with 2 strap-ons) variant.


For more information about Indian Space Research Organisation(ISRO), visit: https://www.isro.gov.in/


Images, Video, Text, Credits: Indian Space Research Organisation (ISRO)/SciNews/Orbiter.ch Aerospace/Roland Berga.


Greetings, Orbiter.chArchive link


Hubble Sees Plunging Galaxy Losing Its Gas



Credits:  NASA, ESA, M. Sun (University of Alabama), and W. Cramer and J. Kenney (Yale University)




Credits: Hubble image: NASA, ESA, M. Sun (University of Alabama), and W. Cramer and J. Kenney (Yale University) 

Subaru image: M. Yagi (National Astronomical Observatory of Japan)




The rough-and-tumble environment near the center of the massive Coma galaxy cluster is no match for a wayward spiral galaxy. New images from NASA’s Hubble Space Telescope show a spiral galaxy being stripped of its gas as it plunges toward the cluster’s center. A long, thin streamer of gas and dust stretches like taffy from the galaxy’s core and on into space. Eventually, the galaxy, named D100, will lose all of its gas and become a dead relic, deprived of the material to create new stars and shining only by the feeble glow of old, red stars.


“This galaxy stands out as a particularly extreme example of processes common in massive clusters, where a galaxy goes from being a healthy spiral full of star formation to a ‘red and dead galaxy,'” said William Cramer of Yale University in New Haven, Connecticut, leader of the team using the Hubble observations. “The spiral arms disappear, and the galaxy is left with no gas and only old stars. This phenomenon has been known about for several decades, but Hubble provides the best imagery of galaxies undergoing this process.”


Called “ram pressure stripping,” the process occurs when a galaxy, due to the pull of gravity, falls toward the dense center of a massive cluster of thousands of galaxies, which swarm around like a hive of bees. During its plunge, the galaxy plows through intergalactic material, like a boat moving through water. The material pushes gas and dust from the galaxy. Once the galaxy loses all of its hydrogen gas — fuel for starbirth — it meets an untimely death because it can no longer create new stars. The gas-stripping process in D100 began roughly 300 million years ago.


In the massive Coma cluster this violent gas-loss process occurs in many galaxies. But D100 is unique in several ways. Its long, thin tail is its most unusual feature. The tail, a mixture of dust and hydrogen gas, extends nearly 200,000 light-years, about the width of two Milky Way galaxies. But the pencil-like structure is comparatively narrow, only 7,000 light-years wide.


“The tail is remarkably well-defined, straight and smooth, and has clear edges,” explained team member Jeffrey Kenney, also of Yale University. “This is a surprise because a tail like this is not seen in most computer simulations. Most galaxies undergoing this process are more of a mess. The clean edges and filamentary structures of the tail suggest that magnetic fields play a prominent role in shaping it. Computer simulations show that magnetic fields form filaments in the tail’s gas. With no magnetic fields, the tail is more clumpy than filamentary.”


The researchers’ main goal was to study star formation along the tail. Hubble’s sharp vision uncovered the blue glow of clumps of young stars. The brightest clump in the middle of the tail contains at least 200,000 stars, triggered by the ongoing gas loss from the galaxy. However, based on the amount of glowing hydrogen gas contained in the tail, the team had expected Hubble to uncover three times more stars than it detected.


The Subaru Telescope in Hawaii observed the glowing tail in 2007 during a survey of the Coma cluster’s galaxies. But the astronomers needed Hubble observations to confirm that the hot hydrogen gas contained in the tail was a signature of star formation.


“Without the depth and resolution of Hubble, it’s hard to say if the glowing hydrogen-gas emission is coming from stars in the tail or if it’s just from the gas being heated,” Cramer said. “These Hubble visible-light observations are the first and best follow-up of the Subaru survey.”


The Hubble data show that the gas-stripping process began on the outskirts of the galaxy and is moving in towards the center, which is typical in this type of mass loss. Based on the Hubble images, the gas has been cleared out all the way down to the central 6,400 light-years.


Within that central region, there is still a lot of gas, as seen in a burst of star formation. “This region is the only place in the galaxy where gas exists and star formation is taking place,” Cramer said. “But now that gas is being stripped out of the center, forming the long tail.”


Adding to this compelling narrative is another galaxy in the image that foreshadows D100’s fate. The object, named D99, began as a spiral galaxy similar in mass to D100. It underwent the same violent gas-loss process as D100 is now undergoing, and is now a dead relic. All of the gas was siphoned from D99 between 500 million and 1 billion years ago. Its spiral structure has mostly faded away, and its stellar inhabitants consist of old, red stars. “D100 will look like D99 in a few hundred million years,” Kenney said.


The Coma cluster is located 330 million light-years from Earth.


The team’s results appear online in the January 8, 2019, issue of The Astrophysical Journal.


The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.






Related Links


This site is not responsible for content found on external links





Contact



Donna Weaver / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland
410-338-4493 / 410-338-4514
dweaver@stsci.edu / villard@stsci.edu


William Cramer
Yale University, New Haven, Connecticut
william.cramer@yale.edu


Jeffrey Kenney
Yale University, New Haven, Connecticut
203-432-3013
jeff.kenney@yale.edu








Archive link


Lasting Memory You probably have countless precious childhood…


Lasting Memory


You probably have countless precious childhood memories, but can barely remember what you had for lunch last Tuesday. That’s because long and short term memories form in our brain in very different ways. Creating long term memories involves creating new proteins, such as CrebB. To understand where and when CrebB does its work in both humans and other animals, researchers genetically modified fruit flies so they could deactivate it in certain areas of the brain. They found that for the flies to remember a particular smell linked to a sugary reward, CrebB, stained red in the fly brain pictured, only needed to be active in specific regions and cells. In humans, defects in CrebB are linked to intellectual disability, addiction and depression, so as well as untangling one more layer in the complex web of memory mechanisms, this work might provide a new tool for studying mental health.


Written by Anthony Lewis



You can also follow BPoD on Instagram, Twitter and Facebook


Archive link


Featured

    Солнечное затмение 14 декабря 2020 года  — полное  солнечное затмение  142  сароса , которое лучше всего будет видно в юго-восточной час...

Popular