суббота, 6 апреля 2019 г.

DNA Doubled Naturally occurring DNA consists of four building…


DNA Doubled


Naturally occurring DNA consists of four building blocks, or nucleotides, spelled out by the letters G, C, A and T. Scientists have calculated that, in theory, other ‘letters’ chemically similar to the existing four are capable of integrating into DNA molecules. But, for whatever reason, evolution did not choose them. Putting that theory to the test, researchers have now shown that indeed four of these alternative nucleotides (Z, P, S and B) can, together with G, C, A and T, form DNA molecules with double the genetic alphabet. This synthetic DNA looks and behaves like the real thing. The video shows a molecular model of the eight-letter DNA with a standard double-helix structure – and can even be used to make eight-letter RNAs – DNA-encoded molecules with catalytic capabilities. By creating RNAs with novel nucleotides, the potential functions of these molecules have vastly increased, as have their potential biotechnological and medical applications.


Written by Ruth Williams



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Music for space


ISS – International Space Station logo.


6 April 2019


Music has long been known to affect people’s mood. A certain tune can lift you up or bring you to tears, make you focus, relax or even run faster. Now a study is investigating how the power of music may improve human performance in one of the most stressful and alien environments we know – space.



Thomas Pesquet with saxophone in Cupola

Music can help release a cocktail of hormones that have a positive effect on us: oxytocin, endorphin, serotonin and dopamine. Besides the pleasure we get from it, music can be used to prolong efficiency and reduce anxiety.


Stress factors in space can lead to disrupted sleep, impaired time perception and spatial orientation.


“Space appeared to me as the perfect testing ground to use anti-stress music,” says violin teacher Luis Luque Álvarez, whose ‘Music for space’ project puts the psycho-physiological research of music at the service of space exploration.


As a child, Luis dreamt of two things: playing violin in an orchestra and space travel.



Catherine Coleman plays a flute on the Space Station

In his thirties as a talented violinist in Hungary, he noticed some videos of astronauts playing instruments in space.


He started to research and learned that music is a part of the astronauts’ daily lives in space, from launch, when mission control plays music to the crews during the countdown, to orbit, where every astronaut has their own playlist to listen to in off-duty moments.


Could he scientifically select the best music to reduce the stress of a crew member?


Press play – Experimenting with music


Fast forward to the ‘Music for Space’ experiment, which ran last year at DLR’s Short Arm Human Centrifuge as part of the first Spin Your Thesis! – Human Edition.


Ten volunteers rode on a centrifuge, being spun until they felt one and a half times the weight of their bodies.  Half of them listened to Beethoven’s ninth symphony and the Planet Earth II soundtrack by Hans Zimmer, Jasha Klebe and Jacob Shea, while the other five spun with no music.



Music for Space experiment

“Exposing people to repeated hypergravity could help us finding countermeasures to maintain wellbeing on space exploration missions,” explains David Green, education coordinator at the European Astronaut Centre in Cologne, Germany.


Coping with hypergravity is not always easy. Changes in the vestibular system can lead to disorientation and dizziness. Test subjects can become tense, anxious or even fearful.


The team from Hungarian and French universities evaluated the stress levels on the subjects by looking at muscle tone with a device called the Myoton, as well as measuring the levels of stress hormones and recording the subjects’ feelings.


The music samples were shortlisted after taking into account both the changes in speed of the centrifuge and the preferences of the listeners.



A subject being connected to all the various sensors prior to the spin

The study showed that music had a positive impact, but would need more tests to get statistically meaningful results. Participants had a tendency to prefer a slow pace, constant pitch music to ease through the acceleration.


Jasha Klebe, co-composer of the Planet Earth II music, said, “It’s amazing to hear our music has had the ability to exist far beyond the series itself.  I have such tremendous respect for anyone involved in space exploration and can only imagine the pressures astronauts endure.


“It’s an incredible honour to have our music used in experiments by ESA. We wrote the music for Planet Earth II to evoke wonder, curiosity and the importance of preserving this natural world, so it’s inspiring to hear our music included within a programme dedicated to exploring worlds beyond our own.”


Space oddities


Luis believes in music therapy beyond Earth, and says “My dream would be to play tailored sets of music to the crew in deep space missions. Mission control could pick up the playlist according to the needs of the mission, and astronauts could also make their choices according to their mood or goals.”



Astronaut Chris Hadfield plays guitar in space

Today, there are two guitars, a keyboard and a saxophone on the International Space Station, but instruments would also be part of future trips, too. Scientists have found that playing an instrument can result in immediate benefits to several brain functions, strengthening memory and reading skills as well as increasing reaction times.



Chris Hadfield sings & plays guitar on ISS – Space Oddity – David Bowie

Back on Earth, the ‘Music for Space’ project aims to putt the space music library at the service of communities in distress. “Music is not just leisure. It is a very special gift to humankind, to be used with care and intelligence,” concludes Luis.


Related links:


Spin Your Thesis! – Human Edition: https://www.esa.int/Education/Spin_Your_Thesis!_Human_Edition/First_ever_Spin_Your_Thesis!_Human_Edition_Campaign_concludes


Spin your thesis!: http://www.esa.int/ESA_Multimedia/Images/2017/11/Spin_Your_Thesis!_Human_Edition_logo


ESA on Soundcloud: https://soundcloud.com/esa


European space laboratory Columbus: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Columbus


Human and Robotic Exploration: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration


International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html


Images, Videos, Text, Credits: ESA/NASA/ASC-CSA/ROSCOSMOS.


Best regards, Orbiter.chArchive link


Philip’s Fountain: The Oldest Still-In-Use Hydraulic Work in the World

Philip’s Fountain: The Oldest Still-In-Use Hydraulic Work in the WorldSource


hellenic-macedonia:Thessaloniki, Ancient era, MacedoniaGreece







hellenic-macedonia:



Thessaloniki, Ancient era, MacedoniaGreece



Source


hellenic-macedonia: Archaelogocal Museum of Samothrace island,…


hellenic-macedonia:



Archaelogocal Museum of Samothrace island, Greece


Ancient Macedonian frieze of choral dancers from the Samothrace Temple Complex, known as the Sanctuary of the Great Gods on the island of Samothrace within the larger Thrace, built before 4th century BC



Source


hellenic-macedonia: The Lady of Aigai, possible wife of Amyntas…



hellenic-macedonia:



The Lady of Aigai, possible wife of Amyntas I, king of Macedon.
5th Century B.C., Aigai, MacedoniaGreece.


“Βuried with a gold mask over her face, gold earrings, a headband over her hair and a necklace of gold beads. Her dress was fastened with silver pins, terminating in gold orbs in the shape of poppy capsules. Rosettes and other gold ornaments were sewn on various places of her dress. Also buried with her were a large number of clay figurines, a silver phiale and bronze vessels.”



Source


hellenic-macedonia: Archaeological Museum of Thessaloniki,…






hellenic-macedonia:



Archaeological Museum of Thessaloniki, MacedoniaGreece


Some more details from a marble bed found in a tomb in Potidaia. The tomb and the two beds discovered in it were covered in depictions of deities and hunting scenes with griffins, panthers, bulls and boars. The bones of the deceased had been arranged on the beds. The tomb was built circa 300 B.C.


http://greek-museums.tumblr.com/archive/2015/1



Source


chromatocloo: Pieces of Viking pottery with traces of cat and…


chromatocloo:



Pieces of Viking pottery with traces of cat and dog paws, seen at the Musée de Normandie in Caen Castle


“So back in the day pets already ruined their owner’s artwork.” – My sis who took the photo



Source


Parker Solar Probe Completes Second Close Approach to the Sun


NASA – Solar Parker Probe patch.


April 5, 2019


Parker Solar Probe has successfully completed its second close approach to the Sun, called perihelion, and is now entering the outbound phase of its second solar orbit. At 6:40 p.m. EDT on April 4, 2019, the spacecraft passed within 15 million miles of our star, tying its distance record as the closest spacecraft ever to the Sun; Parker Solar Probe was traveling at 213,200 miles per hour during this perihelion.


The Parker Solar Probe mission team at the Johns Hopkins Applied Physics Laboratory, or APL, in Laurel, Maryland scheduled a contact with the spacecraft via the Deep Space Network for four hours around the perihelion and monitored the health of the spacecraft throughout this critical part of the encounter. Parker Solar Probe sent back beacon status “A” throughout its second perihelion, indicating that the spacecraft is operating well and all instruments are collecting science data.



“The spacecraft is performing as designed, and it was great to be able to track it during this entire perihelion,” said Nickalaus Pinkine, Parker Solar Probe mission operations manager at APL.Animation of Parker Solar Probe passing close to the Sun “We’re looking forward to getting the science data down from this encounter in the coming weeks so the science teams can continue to explore the mysteries of the corona and the Sun.”


Parker Solar Probe began this solar encounter on March 30, and it will conclude on April 10. The solar encounter phase is roughly defined as when the spacecraft is within 0.25 AU — or 23,250,000 miles — of the Sun. One AU, or astronomical unit, is about 93 million miles, the average distance from the Sun to Earth.


Solar Parker Probe: https://www.nasa.gov/content/goddard/parker-solar-probe


Animation, Text, Credits: NASA/Johns Hopkins University Applied Physics Lab, by Geoff Brown.


Greetings, Orbiter.chArchive link


2019 April 6 ISS from Wallasey Image Credit & Copyright: …


2019 April 6


ISS from Wallasey
Image Credit & Copyright: Richard Addis


Explanation: After sunset on March 28, the International Space Station climbed above the western horizon, as seen from Wallasey, England at the mouth of the River Mersey. Still glinting in the sunlight some 400 kilometers above planet Earth, the fast moving ISS was followed by hand with a small backyard telescope and high frame rate digital camera. A total of 2500 frames were recorded during the 7 minute long visible ISS passage and 100 of them captured images of the space station. These are the four best frames showing remarkable details of the ISS in low Earth orbit. Near the peak of its track, about 60 degrees above the horizon, the ISS was brighter than the brightest star in the sky and as close as 468 kilometers to the Wallasey backyard.


∞ Source: apod.nasa.gov/apod/ap190406.html


Space Station Science Highlights: Week of March 25, 2019


ISS – Expedition 59 Mission patch.


April 5, 2019


Last week, the six astronauts of Expedition 59  aboard the International Space Station prepared for the second spacewalk in as many weeks, and conducted science experiments on the orbiting lab. NASA astronauts Nick Hague and Christina Koch conducted the second spacewalk Friday, March 29, continuing work to install lithium-ion batteries for a pair of the station’s solar arrays.


Read more about some of the science conducted during the week of March 25 on the space station:


Muscling in on better rehabilitation


The Myotones investigation observes the biochemical properties of muscles, such as tone, stiffness, and elasticity, during long-term exposure to spaceflight. Results from this investigation could provide insight into principles of human resting muscle tone and lead to the development of new treatments for rehabilitation on future space missions and on Earth. The crew performed the first sessions of measurements for the investigation during the week of March 25.



Animation above: Astronaut Nick Hague packs the Meteor Camera and associated hardware from the Window Observational Research Facility (WORF) for return to Earth. Meteor made the first space-based observations of the chemical composition of meteors entering Earth’s atmosphere. Animation Credit: NASA.


Understanding heat transfer in microgravity


The crew altered settings for the JAXA Two Phase Flow-2 experiment, changing the valve setting to the Low-mode (pump) of the Metal Heated Tube (MHT) for several runs of the experiment. Two-Phase Flow investigates the heat transfer characteristics of flow boiling in microgravity to better understand bubble formation behavior, liquid-vapor flow in a tube, and how cooling systems transfer heat. Two-Phase Flow employs a cooling loop using perfluorohexane, often used in coolant for electronics, to establish flow rate, heating power, and other effects on different conditions.



International Space Station (ISS). Image Credit: NASA

Keeping blood flowing to the brain


Crew members took measurements for the Cerebral Autoregulation experiment. The brain needs a strong and reliable blood supply so that it is capable of self-regulating blood flow even when the heart and blood vessels cannot maintain an ideal blood pressure. The Cerebral Autoregulation investigation tests whether this self-regulation improves in the microgravity environment of space. Non-invasive tests measure blood flow in the brain before, during, and after a long-duration spaceflight and provide new insights into how the brain safeguards its blood supply in a challenging environment.


Watching daily rhythms



Image above: One of the Actiwatch devices, a waterproof, nonintrusive, sleep-wake monitor worn on the wrist of a crew member. Image Credits: Philips Respironics Inc.


The Actiwatch is a waterproof, nonintrusive, sleep-wake activity monitor that crew members wear on their wrist. The device contains an accelerometer to measure motion and color sensitive photodetectors for monitoring ambient lighting. With these capabilities, Actiwatch Spectrum can analyze the crew’s circadian rhythms, sleep-wake patterns, and activity.


Other investigations on which the crew performed work:


– Future long-duration space missions will require crew members to grow their own food. Veg-03H uses the Veggie plant growth facility to cultivate Extra Dwarf Pak Choi and Wasabi mustard for harvest on-orbit: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1159


– The Combustion Integrated Rack (CIR) includes an optics bench, combustion chamber, fuel and oxidizer control, and five different cameras for performing combustion investigations in microgravity: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=317


– Lighting Effects studies the effects that replacing fluorescent light bulbs on the space station with solid-state light-emitting diodes (LEDs) has on crew member circadian rhythms, sleep, and cognitive performance: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=2013


– RADI-N2, a Canadian Space Agency investigation, seeks to characterize the neutron environment aboard the space station, define the risk it poses to the crew, and provide data to develop better protective measures for future spaceflights: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=874


– The Material Science Research Rack (MSRR) is used for basic materials research in the microgravity environment of the ISS and can accommodate and support diverse Experiment Modules: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=318


– Food Acceptability examines changes in the appeal of food aboard the space station during long-duration missions: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7562



Space to Ground: Power Walking: 03/29/2019

Related links:


Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/expedition59/index.html


Myotones: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7573


Two Phase Flow-2: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1034


Cerebral Autoregulation: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1938


Actiwatch: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=838


Spot the Station: https://spotthestation.nasa.gov/


Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html


International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html


Images (mentioned), Animation (mentioned), Video (NASA), Text, Credits: NASA/Michael Johnson/Jorge Sotomayor, Lead Increment Scientist Expeditions 59/60.


Best regards, Orbiter.chArchive link


Unexpected Rain on Sun Links Two Solar Mysteries


NASA – Solar Dynamics Observatory (SDO) patch.


April 5, 2019


For five months in mid 2017, Emily Mason did the same thing every day. Arriving to her office at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, she sat at her desk, opened up her computer, and stared at images of the Sun — all day, every day. “I probably looked through three or five years’ worth of data,” Mason estimated. Then, in October 2017, she stopped. She realized she had been looking at the wrong thing all along.


Mason, a graduate student at The Catholic University of America in Washington, D.C., was searching for coronal rain: giant globs of plasma, or electrified gas, that drip from the Sun’s outer atmosphere back to its surface. But she expected to find it in helmet streamers, the million-mile tall magnetic loops — named for their resemblance to a knight’s pointy helmet — that can be seen protruding from the Sun during a solar eclipse. Computer simulations predicted the coronal rain could be found there. Observations of the solar wind, the gas escaping from the Sun and out into space, hinted that the rain might be happening. And if she could just find it, the underlying rain-making physics would have major implications for the 70-year-old mystery of why the Sun’s outer atmosphere, known as the corona, is so much hotter than its surface.  But after nearly half a year of searching, Mason just couldn’t find it. “It was a lot of looking,” Mason said, “for something that never ultimately happened.”



Image above: Mason searched for coronal rain in helmet streamers like the one that appears on the left side of this image, taken during the 1994 eclipse as viewed from South America. A smaller pseudostreamer appears on the western limb (right side of image). Named for their resemblance to a knight’s pointy helmet, helmet streamers extend far into the Sun’s faint corona and are most readily seen when the light from the Sun’s bright surface is occluded. Image Credits: © 1994 Úpice observatory and Vojtech Rušin, © 2007 Miloslav Druckmüller.


The problem, it turned out, wasn’t what she was looking for, but where. In a paper published today in the Astrophysical Journal Letters, Mason and her coauthors describe the first observations of coronal rain in a smaller, previously overlooked kind of magnetic loop on the Sun. After a long, winding search in the wrong direction, the findings forge a new link between the anomalous heating of the corona and the source of the slow solar wind — two of the biggest mysteries facing solar science today.


How It Rains on the Sun


Observed through the high-resolution telescopes mounted on NASA’s SDO spacecraft, the Sun – a hot ball of plasma, teeming with magnetic field lines traced by giant, fiery loops — seems to have few physical similarities with Earth. But our home planet provides a few useful guides in parsing the Sun’s chaotic tumult: among them, rain.


On Earth, rain is just one part of the larger water cycle, an endless tug-of-war between the push of heat and pull of gravity. It begins when liquid water, pooled on the planet’s surface in oceans, lakes, or streams, is heated by the Sun. Some of it evaporates and rises into the atmosphere, where it cools and condenses into clouds. Eventually, those clouds become heavy enough that gravity’s pull becomes irresistible and the water falls back to Earth as rain, before the process starts anew.


On the Sun, Mason said, coronal rain works similarly, “but instead of 60-degree water you’re dealing with a million-degree plasma.” Plasma, an electrically-charged gas, doesn’t pool like water, but instead traces the magnetic loops that emerge from the Sun’s surface like a rollercoaster on tracks. At the loop’s foot points, where it attaches to the Sun’s surface, the plasma is superheated from a few thousand to over 1.8 million degrees Fahrenheit. It then expands up the loop and gathers at its peak, far from the heat source. As the plasma cools, it condenses and gravity lures it down the loop’s legs as coronal rain.



Animation above: Coronal rain, like that shown in this movie from NASA’s SDO in 2012, is sometimes observed after solar eruptions, when the intense heating associated with a solar flare abruptly cuts off after the eruption and the remaining plasma cools and falls back to the solar surface. Mason was searching for coronal rain not associated with eruptions, but instead caused by a cyclical process of heating and cooling similar to the water cycle on Earth. Image Credits: NASA’s Solar Dynamics Observatory/Scientific Visualization Studio/Tom Bridgman, Lead Animator.


Mason was looking for coronal rain in helmet streamers, but her motivation for looking there had more to do with this underlying heating and cooling cycle than the rain itself. Since at least the mid-1990s, scientists have known that helmet streamers are one source of the slow solar wind, a comparatively slow, dense stream of gas that escapes the Sun separately from its fast-moving counterpart.  But measurements of the slow solar wind gas revealed that it had once been heated to an extreme degree before cooling and escaping the Sun. The cyclical process of heating and cooling behind coronal rain, if it was happening inside the helmet streamers, would be one piece of the puzzle.


The other reason connects to the coronal heating problem — the mystery of how and why the Sun’s outer atmosphere is some 300 times hotter than its surface. Strikingly, simulations have shown that coronal rain only forms when heat is applied to the very bottom of the loop. “If a loop has coronal rain on it, that means that the bottom 10% of it, or less, is where coronal heating is happening,” said Mason. Raining loops provide a measuring rod, a cutoff point to determine where the corona gets heated. Starting their search in the largest loops they could find — giant helmet streamers — seemed like a modest goal, and one that would maximize their chances of success.


She had the best data for the job: Images taken by NASA’s Solar Dynamics Observatory, or SDO, a spacecraft that has photographed the Sun every twelve seconds since its launch in 2010. But nearly half a year into the search, Mason still hadn’t observed a single drop of rain in a helmet streamer. She had, however, noticed a slew of tiny magnetic structures, ones she wasn’t familiar with. “They were really bright and they kept drawing my eye,” said Mason. “When I finally took a look at them, sure enough they had tens of hours of rain at a time.”


At first, Mason was so focused on her helmet streamer quest that she made nothing of the observations. “She came to group meeting and said, ‘I never found it — I see it all the time in these other structures, but they’re not helmet streamers,’” said Nicholeen Viall, a solar scientist at Goddard, and a coauthor of the paper. “And I said, ‘Wait…hold on. Where do you see it? I don’t think anybody’s ever seen that before!’”


A Measuring Rod for Heating


These structures differed from helmet streamers in several ways. But the most striking thing about them was their size.


“These loops were much smaller than what we were looking for,” said Spiro Antiochos, who is also a solar physicist at Goddard and a coauthor of the paper. “So that tells you that the heating of the corona is much more localized than we were thinking.”



Animation above: Mason’s article analyzed three observations of Raining Null-Point Topologies, or RNTPs, a previously overlooked magnetic structure shown here in two wavelengths of extreme ultraviolet light. The coronal rain observed in these comparatively small magnetic loops suggests that the corona may be heated within a far more restricted region than previously expected. Image Credits: NASA’s Solar Dynamics Observatory/Emily Mason.


While the findings don’t say exactly how the corona is heated, “they do push down the floor of where coronal heating could happen,” said Mason. She had found raining loops that were some 30,000 miles high, a mere two percent the height of some of the helmet streamers she was originally looking for. And the rain condenses the region where the key coronal heating can be happening. “We still don’t know exactly what’s heating the corona, but we know it has to happen in this layer,” said Mason.


A New Source for the Slow Solar Wind


But one part of the observations didn’t jibe with previous theories.  According to the current understanding, coronal rain only forms on closed loops, where the plasma can gather and cool without any means of escape. But as Mason sifted through the data, she found cases where rain was forming on open magnetic field lines. Anchored to the Sun at only one end, the other end of these open field lines fed out into space, and plasma there could escape into the solar wind. To explain the anomaly, Mason and the team developed an alternative explanation — one that connected rain on these tiny magnetic structures to the origins of the slow solar wind.



Solar Dynamics Obsrvatory (SDO). Image Credit: NASA

In the new explanation, the raining plasma begins its journey on a closed loop, but switches — through a process known as magnetic reconnection — to an open one. The phenomenon happens frequently on the Sun, when a closed loop bumps into an open field line and the system rewires itself.  Suddenly, the superheated plasma on the closed loop finds itself on an open field line, like a train that has switched tracks. Some of that plasma will rapidly expand, cool down, and fall back to the Sun as coronal rain. But other parts of it will escape – forming, they suspect, one part of the slow solar wind.


Mason is currently working on a computer simulation of the new explanation, but she also hopes that soon-to-come observational evidence may confirm it. Now that Parker Solar Probe, launched in 2018, is traveling closer to the Sun than any spacecraft before it, it can fly through bursts of slow solar wind that can be traced back to the Sun — potentially, to one of Mason’s coronal rain events. After observing coronal rain on an open field line, the outgoing plasma, escaping to the solar wind, would normally be lost to posterity. But no longer. “Potentially we can make that connection with Parker Solar Probe and say, that was it,” said Viall.


Digging Through the Data


As for finding coronal rain in helmet streamers? The search continues. The simulations are clear: the rain should be there. “Maybe it’s so small you can’t see it?” said Antiochos.  “We really don’t know.”


But then again, if Mason had found what she was looking for she might not have made the discovery — or have spent all that time learning the ins and outs of solar data.


“It sounds like a slog, but honestly it’s my favorite thing,” said Mason. “I mean that’s why we built something that takes that many images of the Sun: So we can look at them and figure it out.”


Related links:


IRIS Spots Plasma Rain on Sun’s Surface: https://www.nasa.gov/feature/goddard/2016/iris-spots-plasma-rain-on-suns-surface


And the Blobs Just Keep on Coming: https://www.nasa.gov/feature/goddard/2019/and-the-blobs-just-keep-on-coming


SDO (Solar Dynamics Observatory): http://www.nasa.gov/mission_pages/sdo/main/index.html


Images (mentioned), Animations (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Miles Hatfield.


Greetings, Orbiter.chArchive link


Spacewalk This Monday Ahead of Two U.S. Cargo Missions This Month


ISS – Expedition 59 Mission patch.


April 5, 2019


The Expedition 59 crew is going into the weekend preparing for another spacewalk on Monday. The International Space Station residents also continue microgravity research as they wait for two U.S. cargo ships to arrive before the end of the month.


Astronauts Anne McClain and David Saint-Jacques are getting their tools ready for another power upgrades spacewalk and will wrap up their final procedures review on Sunday. The spacewalkers will set their spacesuits to battery power around 8:05 a.m. EDT Monday signifying the start of their spacewalk and exit the space station’s Quest airlock.



Image above: Astronaut David Saint-Jacques of the Canadian Space Agency works on a pair of U.S. spacesuits inside the Quest airlock ahead of a trio of spacewalks to upgrade power systems on the International Space Station. Image Credit: NASA.


The duo will work outside for about six-and-a-half hours installing truss jumpers to provide a redundant power source to the Canadarm2 robotic arm. McClain and Saint-Jacques will also install cables to update the station’s External Wireless Communications system. NASA TV starts its live coverage at 6:30 a.m. Monday.


Russia’s Progress 72 (72P) resupply ship delivered over 3.7 tons of food, fuel and supplies after docking to the Pirs docking compartment Thursday morning. Next up is Northrop Grumman’s Cygnus space freighter when it launches from Virginia on April 17 on a two-day ride to the station’s Unity module. SpaceX follows in late April when its Dragon cargo craft blasts off from Florida on a two-day trip to the orbital lab’s Harmony module.



International Space Station (ISS)

Virtual reality filming and space research continued full pace inside the orbital lab today. Flight Engineer Christina Koch first strapped herself into an exercise bike to measure her aerobic capacity then set up a virtual reality camera inside the Unity module today. Nick Hague of NASA then recorded himself describing his space experiences for a short immersive, cinematic film.


Cosmonauts Oleg Kononenko and Alexey Ovchinin unloaded the new 72P and worked on an array of life science experiments in the orbital lab’s Russian segment. The duo photographed red blood samples and microbes to help doctors keep long-term crews healthy in space.


Related article:


Express Delivery from Russia Brings 3.7 Tons of Station Supplies
https://orbiterchspacenews.blogspot.com/2019/04/express-delivery-from-russia-brings-37.html


Related links:


Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/expedition59/index.html


Quest airlock: https://www.nasa.gov/mission_pages/station/structure/elements/joint-quest-airlock


Canadarm2 robotic arm: https://www.nasa.gov/mission_pages/station/structure/elements/mobile-servicing-system.html


NASA TV: https://www.nasa.gov/nasatv


Pirs docking compartment: https://www.nasa.gov/mission_pages/station/structure/elements/pirs-docking-compartment


Unity module: https://www.nasa.gov/mission_pages/station/structure/elements/unity


Harmony module: https://www.nasa.gov/mission_pages/station/structure/elements/harmony


Aerobic capacity: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=644


Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html


International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html


Image (mentioned), Animation, Text, Credits: NASA/Mark Garcia.


Best regards, Orbiter.chArchive link


hellenic-macedonia: https://www.pinterest.com/pin/283445370267681…


hellenic-macedonia:



https://www.pinterest.com/pin/283445370267681454/


Ram’s head rock-crystal bracelet styled like a torque (ca. 330-300 B.C.). Found in Macedonia, near Thessaloniki, GREECE             



Source


hellenic-macedonia: Archeological Museum of Thasos…


hellenic-macedonia:



Archeological Museum of Thasos Island


Colossal statue (h. 3.50 m.) of a young, naked man (kouros), carrying a ram. The statue is unfinished and it seems that the sculptor abandoned his work because of a crack in the marble near the left ear. Dated to ca. 600 B.C.



Source


hellenic-macedonia: Ionic capital of the late archaic temple of…


hellenic-macedonia:



Ionic capital of the late archaic temple of goddess Parthenos, end of 6th century BC.


MacedoniaGreece



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Scientists measure extent of recovery for critically endangered black abalone

One critically endangered species of smooth-shelled abalone is making a comeback in certain parts of its range along the California coast. To better understand the extent of black abalone recovery, a collaborative team led by scientists at the California Academy of Sciences, San Diego State University, University of Oregon, and Channel Islands National Park is turning to archeological sites on the Channel Islands. Their findings, published in Ecology and Evolution, suggest that while the recent ecological rebound is encouraging, there’s still work to do before the black abalone should be considered fully recovered.











Scientists measure extent of recovery for critically endangered black abalone
A 19th-century archaeological abalone fishing site on the Northern Channel Islands
[Credit: © 2015 Hannah Haas]

“Our goal is to provide a deep historical lens for understanding black abalone across 10,000 years of human fishing,” says Dr. Todd Braje, Academy Curator of Anthropology. “Documenting abalone populations across millennia helps resource managers put shorter-term decadal changes in context. We hope these data will serve as a new benchmark for setting management goals.”


Black abalone play a critical role in the kelp ecosystem along the California coast. The marine snails are an important food source for key predators like the endangered sea otter. Historically, coastal Native Americans relied on abalone for over 10,000 years–the shellfish later became one of California’s first commercial fisheries.


“Management goals are often set using modern data from fisheries already on the verge of collapse,” says lead author Hannah Haas, a former Master’s student at San Diego State University. “If we want to restore kelp ecosystems, we first have to understand what a healthy system actually looks like, and archeological data can help paint that picture.”


To better understand the characteristics of a flourishing abalone population in a historically healthy ecosystem, the study team turned to the archeological record left behind along the rocky shorelines of the Channel Islands. San Miguel Island, the westernmost island in the archipelago, hosts archeological sites spanning the last 10,000 years where the Chumash and their ancestors once deposited abalone shells by the thousands into trash piles known as shell middens.











Scientists measure extent of recovery for critically endangered black abalone
The study team conducts a shoreline survey of prehistoric Chumash sites, which often contain
discarded abalone shell [Credit: © 2015 Todd Braje]

The team recovered nearly 2,000 whole abalone shells from 26 shell middens and measured shell size. They then compared deep historical shell size to modern measurements of live abalone collected by Channel Island National Park biologists during recent ecological monitoring. Shell size indicates the ratio of juveniles to adults and the population structure through time, which can help scientists compare and contrast overall population health between deep historical and modern eras.


While there has been an encouraging rebound of black abalone in recent decades, current populations still pale in comparison to historical levels. Several thousand years ago, the distribution of juvenile to adult-sized abalone was more akin to what ecologists recognize as a healthy population. This was probably maintained by a delicate balance between competitors, predators, and prey that may have actually increased the productivity of black abalone over the long term.


“We hope that our long-term analyses over the 10,000-year history of black abalone fishing in Southern California may help resource managers determine whether current abalone populations are healthy,” says Haas.


Millions of smooth-shelled abalone once clung to California’s rocky coastline until a steep decline in the 1990s, driven by overfishing, warming waters, and a devastating infection known as withering foot syndrome. California closed commercial and recreational black abalone fisheries in 1993 and listed the species as endangered in 2009.


“A variety of perspectives and data are key to understanding how to manage toward ecological balance rather than an era defined by commercial fishing, sea otter extirpation, and ecosystem dysfunction,” says Braje. “We’re trying to put together a diverse group of scholars–archeologists, biologists, and resource managers–to combine data insights and all work toward the same goal of abalone recovery and restoring healthy California kelp forest ecosystems.”


Source: California Academy of Sciences [April 02, 2019]



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Food for thought: Why did we ever start farming?

The reason that humans shifted away from hunting and gathering, and to agriculture — a much more labour-intensive process — has always been a riddle. It is only more confusing because the shift happened independently in about a dozen areas across the globe.











Food for thought: Why did we ever start farming?
Woodland Indians first developed farming in Tennessee. Painting by Carlyle Urello
[Credit: Tennessee State Museum]

“A lot of evidence suggests domestication and agriculture doesn’t make much sense,” says Elic Weitzel, a Ph.D. student in UConn’s department of anthropology. “Hunter-gatherers are sometimes working fewer hours a day, their health is better, and their diets are more varied, so why would anyone switch over and start farming?”


Weitzel sought to get to the root of the shift in his new paper in American Antiquity, by looking at one area of the world, the Eastern United States. In a nutshell, he looked for evidence to support either of two popular theories.


One theory posits that in times of plenty there may have been more time to start dabbling in the domestication of plants like squash and sunflowers, the latter of which were domesticated by the native peoples of Tennessee around 4,500 years ago.


The other theory argues that domestication may have happened out of need to supplement diets when times were not as good. As the human population grew, perhaps resources shifted due to reasons such as over-exploitation of resources or a changing climate. “Was there some imbalance between resources and the human populations that lead to domestication?”


Weitzel tested both hypotheses. He did this by analyzing animal bones from the last 13,000 years and taken from a half-dozen archeological sites in northern Alabama and the Tennessee River valley, where human settlements and their detritus give clues about how they lived, including what they ate.He coupled the findings with pollen data taken from sediment cores collected from lakes and wetlands, cores that serve as a record about the types of plants present at different points in time.The findings are … mixed.


Weitzel found pollen from oak and hickory, leading to the conclusion that forests composed of those species began to dominate the region as the climate warmed, but also led to decreasing water levels in lakes and wetlands. Along with the decreasing lakes, the bone records showed a shift from diets rich in water fowl and large fishes to subsistence on smaller shellfish.


Taken together, that data provides evidence for the second hypothesis: There was some kind of imbalance between the growing human population and their resource base, effected perhaps by exploitation and also by climate change.


But Weitzel also saw support for the first hypothesis in that an abundance of oak and hickory forest supported an equally prevalent game species population. “That is what we see in the animal bone data,” says Weitzel.”Fundamentally, when times are good and there are lots of animals present, you’d expect people to hunt the prey that is most efficient,” says Weitzel. “Deer are much more efficient than squirrels for example, which are smaller, with less meat, and more difficult to catch.”


A single deer or goose can feed several people, but if over-hunted, or if the landscape changes to one less favorable for the animal population, humans must subsist on other smaller, less efficient food sources. Agriculture, despite being hard work, may have become a necessary option to supplement diet when imbalances like these occurred.


Despite the mixed results, the findings supporting domestication happening in times when there was less than an ideal amount of food is significant, says Weitzel.


“I think that the existence of declining efficiency in even one habitat type is enough to show that … domestication happening in times of plenty isn’t the best way to understand initial domestication.”The broader context of this research is important, says Weitzel, because looking to the past and seeing how these populations coped and adapted to change can help inform what we should do as today’s climate warms in the coming decades.


“Having an archaeological voice backed by this deep-time perspective in policy making is very important.”


Source: University of Connecticut [April 02, 2019]



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4,000-year-old petroglyphs discovered in Inner Mongolia

Several 4,000-year-old petroglyphs depicting the celebration of birth in a tribe have been discovered in north China’s Inner Mongolia Autonomous Region, archaeologists said.











4,000-year-old petroglyphs discovered in Inner Mongolia
Credit: Xinhua

The petroglyphs were found on two sides of a giant rock in Mandela township in Alxa Right Banner. Many human figures dancing hand in hand are carved on one side, while three people in a row, a female in the middle, are on the other side, according to the local cultural relics bureau.
“These well-preserved petroglyphs depict a tribe celebrating the birth of a child,” said Wu Yi from the bureau. “They record the ancient tribes’ reverence for the prosperity and circle of life.”











4,000-year-old petroglyphs discovered in Inner Mongolia
Credit: Xinhua

Wu said the petroglyphs’ unique content can offer precious materials for Chinese archaeological and anthropological research.
More than 2,000 petroglyphs have been found in Mandela township. Local authorities have hired local herders to patrol on the sites for better protection of the petroglyphs.











4,000-year-old petroglyphs discovered in Inner Mongolia
Credit: Xinhua

More than 1,200 petroglyphs, scattered in over 100 counties in 28 provinces and regions, have been found and recorded across China, according to statistics released by the Chinese Rock Art Association in 2017.


Source: Xinhua News Agency [April 02, 2019]



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8,000-year-old discovery at Abu Dhabi’s Marawah Island

The latest archaeological excavations on Marawah Island have shed new light on Abu Dhabi’s earliest known settlement, which dates back 8,000 years.











8,000-year-old discovery at Abu Dhabi's Marawah Island
Credit: Department of Culture and Tourism – Abu Dhabi

The most recent excavations conducted by specialist teams from the Department of Culture and Tourism – Abu Dhabi (DCT Abu Dhabi) from February to March this year,have uncovered stunning new evidence on the architecture, art and technology of Abu Dhabi’s Neolithic inhabitants.
Marawah lies around 100km to the west of the city of Abu Dhabi, and approximately 25km northwest of the port of Mirfa. The dig site is situated on top of a rocky limestone plateau located just to the west of Ghubba village in the south-western part of the island. First discovered in 1992 during an archaeological survey of the island, the site consists of at least seven mounds that appear to be the remains of collapsed Neolithic stone structures.


8,000-year-old discovery at Abu Dhabi's Marawah Island










8,000-year-old discovery at Abu Dhabi's Marawah Island
Credit: Department of Culture and Tourism – Abu Dhabi

Previous archaeological excavations focused on one of the smaller mounds at the site, and uncovered a well-built, three-room stone structure and a number of significant finds. These included an imported ceramic vase – which the public can now see on display at Louvre Abu Dhabi – as well as flint arrowheads and pearl oyster shell buttons, which are currently on display at Qasr Al Hosn. Other finds retrieved included numerous plaster vessel fragments, shell and stone beads, marine shells, fish bones, mammalian bones from gazelles and dugongs, and cetacean bones from dolphins.
Expanded excavations have taken place at the site since 2017 and these have concentrated on the largest mound, revealing the presence of numerous stone buildings. The recently completed excavation season successfully uncovered the full extent of this mound with an exceptional range of artefacts found around this unique building. These included a large number of stone arrowheads, as well as decorated and undecorated plaster vessel fragments. The plaster vessel fragments are richly painted and represent the earliest known decorative art yet discovered in the UAE.


8,000-year-old discovery at Abu Dhabi's Marawah Island










8,000-year-old discovery at Abu Dhabi's Marawah Island
Credit: Department of Culture and Tourism – Abu Dhabi

Radiocarbon dating of charcoal fragments from different layers in the site demonstrates that the site was occupied between about 8,000 years ago to about 6,500 years ago. 
Mohamed Khalifa Al Mubarak, Chairman of DCT Abu Dhabi, visited Marawah Island on Monday 18 March to view the progress being made by archaeologists working on the excavation.


“The continuing archaeological excavations we are carrying out on Marawah Island continue to uncover fascinating and revealing discoveries,” said HE Mubarak. “As we at DCT Abu Dhabi work to preserve, promote and protect the heritage sites that embody this history of our region so that they can inform future generations, Marawah Island continues to present stunning evidence of our past which reveals more and more of our storied origins.”


Source: Khaleej Times [April 02, 2019]



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