среда, 17 апреля 2019 г.

NASA Announces First Flight, Record-Setting Mission


ISS — International Space Station patch.


April 17, 2019


NASA and its International Space Station partners have set a new schedule and new crew assignments that will include the first flight of NASA astronaut Jessica Meir, an extended stay for NASA astronaut Andrew Morgan, and a record-setting flight for NASA astronaut Christina Koch.



Astronauts Koch and Meir React to International Space Station Mission Updates

Video above: Astronaut Jessica Meir is now set to fly to the International Space Station for the first time in September, and Christina Koch, who is currently in space, has her stay onboard extended to an expected record-setting flight of 328 days. With Koch now scheduled to remain in orbit until February 2020, she will set a record for the longest single spaceflight by a woman, eclipsing the previous mark set by Peggy Whitson of 288 days in 2016-17. Video Credit: NASA.


Koch, who arrived at the space station March 14, and now is scheduled to remain in orbit until February 2020, will set a record for the longest single spaceflight by a woman, eclipsing the record of 288 days set by former NASA astronaut Peggy Whitson in 2016-17. She will be part of three expeditions – 59, 60 and 61 – during her current first spaceflight. Her mission is planned to be just shy of the longest single spaceflight by a NASA astronaut – 340 days, set by former NASA astronaut Scott Kelly during his one-year mission in 2015-16.


The mission schedule currently is as follows:


June 24: Current Expedition 59 crew members Anne McClain of NASA, David Saint-Jacques of the Canadian Space Agency, and Oleg Kononenko of Roscosmos will return to Earth. Koch and fellow NASA astronaut Nick Hague, and Roscosmos cosmonaut Alexey Ovchinin will remain aboard the space station and begin Expedition 60.


July 20: NASA astronaut Andrew Morgan, ESA (European Space Agency) astronaut Luca Parmitano, and Roscosmos cosmonaut Alexander Skvortsov are scheduled to launch to the space station and join Expedition 60, returning the orbiting laboratory’s crew complement to six. Parmitano and Skvortsov will return in February 2020 with Koch, leaving Morgan behind for his extended stay.


Sept. 25: NASA astronaut Jessica Meir is scheduled to launch to the station with Roscosmos cosmonaut Oleg Skripochka and United Arab Emirates’ Hazzaa Ali Almansoori, a Roscosmos spaceflight participant who will return with Hague and Ovchinin Oct. 3. Meir and Skripochka will return in spring 2020 with Morgan.


The extended missions of Koch and Morgan will help scientists gather additional data about the effects of long-duration human spaceflight beyond those of the normal six-month station expedition. Such research is essential to support future deep space exploration missions to the Moon and Mars.



Image above: NASA astronaut Christina Koch conducts botany research aboard the International Space Station, where she’s been living and working since March 14, 2019. Her mission has been extended, and she will remain at the station until February 2020. Image Credit: NASA.


NASA has gathered vast amounts of data on astronaut health and performance over the past 50 years and has focused recently on extended durations up to one year with the dedicated mission of Scott Kelly and extended mission of Peggy Whitson. These opportunities also have demonstrated that there is a significant degree of variability in human response to spaceflight and it’s important to determine the acceptable degree of change for both men and women.


“Astronauts demonstrate amazing resilience and adaptability in response to long duration spaceflight exposure,” said Jennifer Fogarty, chief scientist of the Human Research Program at NASA’s Johnson Space Center in Houston. “This will enable successful exploration missions with healthy, performance-ready astronauts. NASA is looking to build on what we have learned with additional astronauts in space for more than 250 days. Christina’s extended mission will provide additional data for NASA’s Human Research Program and continue to support future missions to the Moon and Mars.”



Image above: NASA astronaut Jessica Meir trains inside the Space Vehicle Mockup Facility at NASA’s Johnson Space Center. She has been assigned to her first spaceflight, and will launch to the International Space Station in September 2019. Image Credit: NASA.


This schedule also allows NASA to get the most time dedicated to other research aboard the station, as U.S. commercial crew launch providers prepare for operations to and from U.S. soil and the space station.


Meir’s September launch to the station will mark her first spaceflight. The Caribou, Maine, native was selected as an astronaut in 2013, while serving as an assistant professor at Harvard Medical School/Massachusetts General Hospital. She holds a bachelor’s in biology from Brown University, a master’s in space studies from International Space University, and a doctorate in marine biology from Scripps Institution of Oceanography.



Image above: NASA astronaut Drew Morgan trains inside a mockup of the International Space Station at NASA’s Johnson Space Center. His mission, which will launch in July 2019, has been extended through March 2020. Image Credit: NASA.


Prior to her selection to the astronaut corps, Meir’s career focused on the physiology of animals in extreme environments, studying emperor penguins in the Antarctic, elephant seals in California, and bar-headed geese in studies at the University of British Columbia and in Mongolia. Meir also previously worked for Lockheed Martin’s Human Research Facility, participated in reduced gravity research flights, took part in diving expeditions to the Antarctic and Belize, and served as a spaceflight analog crewmember for a NASA Extreme Environment Mission Operations underwater mission and an ESA caving mission (ESA CAVES).


Morgan will make his first flight into space this summer. A New Castle, Pennsylvania, native, Morgan was selected to be an astronaut in 2013, when he was serving as an emergency physician in the U.S. Army with sub-specialty certification in primary care sports medicine. He is a graduate of the U.S. Military Academy at West Point and the Uniformed Services University of the Health Sciences in Bethesda, Maryland.


Related links:


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


Expedition 60: https://www.nasa.gov/mission_pages/station/expeditions/future.html


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


Follow Meir on social media at:


https://www.instagram.com/astro_jessica/ and https://twitter.com/astro_jessica


Follow Koch during her extended mission at:


https://www.instagram.com/astro_christina/ and https://twitter.com/Astro_Christina and https://www.facebook.com/AstroChristina/


Follow Morgan throughout his extended mission at:


https://www.instagram.com/astrodrewmorgan/ and https://twitter.com/AstroDrewMorgan and https://www.facebook.com/AstroDrewMorgan/


Keep up with the International Space Station, and its research and crew, at: https://www.nasa.gov/station


Johnson Space Center (JSC): https://www.nasa.gov/centers/johnson/home/index.html


Images (mentioned), Video (mentioned), Text, Credits: NASA/Karen Northon/Stephanie Schierholz/JSC/Gary Jordan/Brandi Dean.


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Making a Difference One of the challenges to treating cancer…


Making a Difference


One of the challenges to treating cancer is that it’s part of a supportive living body – welcoming blood vessels often reach out to feed the cancerous tissue, a process called angiogenesis. And just as each of our bodies develop differently, so do tumours, complicating the design of drugs, or surgical procedures. Here a new combination of 3D magnetic resonance microscopy and computer modelling investigates the differences, or heterogeneity, of three breast tumours growing in mice. The top row highlights different patterns of blood vessels in similar cancers, with regions of fast flowing blood highlighted in warm colours. Below, pinks and purples show the corresponding oxygen levels in the blood supply. Learning more about the haemodynamics of different tumours, may reveal more about what they have in common – creating a sort of ‘cancer atlas’ and identifying weaknesses for future therapies.


Written by John Ankers



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Castell Henllys Iron Age Settlement, Newport, Wales, 12.4.19.

Castell Henllys Iron Age Settlement, Newport, Wales, 12.4.19.












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cma-korean-art: Necklace, 700, Cleveland Museum of Art: Korean…


cma-korean-art:



Necklace, 700, Cleveland Museum of Art: Korean Art


Medium: jade, amethyst, gold, rock crystal


https://clevelandart.org/art/1945.380



Source


cma-japanese-art: Bishamonten, 1000, Cleveland Museum of Art:…


cma-japanese-art:



Bishamonten, 1000, Cleveland Museum of Art: Japanese Art


Bishamonten, the Buddhist guardian of the North, appears here with an entourage. Early votive mirrors like this one are called kyōzō, literally “mirrors with images.” One theory is that they appeared along with the development of Shinto-Buddhist combinatory thought, in which specific Buddhist deities were identified with specific kami, or Shinto deities. In this theory, sacred mirrors venerated as proxies for kami came to be incised with images of Buddhist deities. Another idea is that they developed in the context of Esoteric Buddhist ritual.
Size: Diameter: 15.3 cm (6 in.)
Medium: silvered bronze


https://clevelandart.org/art/1977.32



Source


cma-japanese-art: Shinto Deities, 900, Cleveland Museum of Art:…


cma-japanese-art:



Shinto Deities, 900, Cleveland Museum of Art: Japanese Art


These sculptures represent kami, the name for deities associated with the Japanese religious tradition known as Shinto. They are said to have originally been created for the Usa Hachiman shrine in Oita on the island of Kyushu. Usa Hachiman Shrine houses four main kami: Hime Okami, who assists those engaged in agriculture and sea travel; the legendary 5th-century emperor Ojin deified as the kami Hachiman; Empress Jingu; and the kami of Mount Kawara, who aids copper miners. The identities of these two figures are unknown, but they belong to a larger group containing at least three other deities.
Size: Overall: 50.3 x 38.1 cm (19 13/16 x 15 in.)
Medium: wood, with traces of polychromy


https://clevelandart.org/art/1978.3



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The Iron Age ‘Cerrigydrudion Crown’ and Reconstruction (405 to 380 BCE) from...

The Iron Age ‘Cerrigydrudion Crown’ and Reconstruction (405 to 380 BCE) from North Wales, displayed at St Fagans National Museum, Cardiff, 14.4.19.









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A New Signal for a Neutron Star Collision Discovered



XT2
Credit: X-ray: NASA/CXC/Uni. of Science and Technology of China/Y. Xue et al; 
Optical: NASA/STScI

JPEG (134.1 kb) Large JPEG (1.8 MB) Tiff (29 MB) More Images


A Tour of XT2  More Animations





These images show the location of an event, discovered by NASA’s Chandra X-ray Observatory, that likely signals the merger of two neutron stars. A bright burst of X-rays in this source, dubbed XT2, could give astronomers fresh insight into how neutron stars — dense stellar objects packed mainly with neutrons — are built.


XT2 is located in a galaxy about 6.6 billion light years from Earth. The source is located in the Chandra Deep Field South (CDF-S), a small patch of sky in the Fornax constellation. The CDF-S is the deepest X-ray image ever taken, containing almost 12 weeks of Chandra observing time. The wider field of view shows an optical image from the Hubble Space Telescope of a portion of the CDF-S field, while the inset shows a Chandra image focusing only on XT2. The location of XT2, which was not detected in optical images, is shown by the rectangle, and its host galaxy is the small, oval-shaped object located slightly to the upper left. 


On March 22, 2015, astronomers saw XT2 suddenly appear in the Chandra data and then fade away after about seven hours. By combing through the Chandra archive, they were able to piece together the history of the source’s behavior. The researchers compared the data from XT2 to theoretical predictions made in 2013 of what the X-ray signature from two colliding neutron stars without a corresponding gamma ray bursts would look like.


When two neutron stars merge they produce jets of high energy particles and radiation fired in opposite directions. If the jet is pointed along the line of sight to the Earth, a flash, or burst, of gamma rays can be detected. If the jet is not pointed in our direction, a different signal is needed to identify the merger. This result provides scientists with an opportunity to study just such a case.


X-rays from XT2 showed a characteristic signature that matched those predicted for a newly-formed magnetar, that is, a neutron star spinning around hundreds of times per second and possessing a tremendously strong magnetic field about a quadrillion times that of Earth’s.


The team think that the magnetar lost energy in the form of an X-ray-emitting wind, slowing down its rate of spin as the source faded. The amount of X-ray emission stayed roughly constant in X-ray brightness for about 30 minutes, then decreased in brightness by more than a factor of 300 over 6.5 hours before becoming undetectable. This showed that the neutron star merger produced a new, larger neutron star and not a black hole.


XT2’s bright flare of X-rays gives astronomers another signal — in addition to the detection of gravitational waves — to probe neutron star mergers.


A paper describing these results appeared in the April 11th issue of Nature, led by Yongquan Xue (University of Science and Technology in China). NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.



Timelapse
Credit: NASA/CXC/Uni. of Science and Technology of China/Y. Xue et al.




When two neutron stars merge they produce jets of high energy particles and radiation fired in opposite directions. If the jet is pointed along the line of sight to the Earth, a flash, or burst, of gamma rays can be detected. If the jet is not pointed in our direction, a different signal is needed to identify the merger. This result provides scientists with an opportunity to study just such a case.


X-rays from XT2 showed a characteristic signature that matched those predicted for a newly-formed magnetar, that is, a neutron star spinning around hundreds of times per second and possessing a tremendously strong magnetic field about a quadrillion times that of Earth’s.


The team think that the magnetar lost energy in the form of an X-ray-emitting wind, slowing down its rate of spin as the source faded. The amount of X-ray emission stayed roughly constant in X-ray brightness for about 30 minutes, then decreased in brightness by more than a factor of 300 over 6.5 hours before becoming undetectable. This showed that the neutron star merger produced a new, larger neutron star and not a black hole.


XT2’s bright flare of X-rays gives astronomers another signal — in addition to the detection of gravitational waves — to probe neutron star mergers.


A paper describing these results appeared in the April 11th issue of Nature, led by Yongquan Xue (University of Science and Technology in China). NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.






Fast Facts for CDF-S XT2:

Scale: Chandra images are about 15 arcsec (360,000 light years) across.
Category: Neutron Stars/X-ray Binaries
Coordinates (J2000): RA 3h 32m 18.38s | Dec -27° 52´ 24.2″
Constellation: Fornax
Observation Date: Mar 22, 2015
Observation Time: 19 hours 27 minutes
Obs. ID: 16453
Instrument: ACIS
References: Xue,Y.Q et al, 2019, Nature.  arXiv:1904.05368
Color Code: X-ray: Orange; Optical: Red
Distance Estimate: About 6.6 billion light years





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2019 April 17 Messier 81 Image Credit & Copyright: Paolo…


2019 April 17


Messier 81
Image Credit & Copyright: Paolo De Salvatore (Zenit Observatory)


Explanation: One of the brightest galaxies in planet Earth’s sky is similar in size to our Milky Way Galaxy: big, beautiful Messier 81. Also known as NGC 3031 or Bode’s galaxy for its 18th century discoverer, this grand spiral can be found toward the northern constellation of Ursa Major, the Great Bear. The detailed telescopic view reveals M81’s bright yellow nucleus, blue spiral arms, pink starforming regions, and sweeping cosmic dust lanes. Some dust lanes actually run through the galactic disk (left of center), contrary to other prominent spiral features though. The errant dust lanes may be the lingering result of a close encounter between M81 and its smaller companion galaxy, M82. Scrutiny of variable stars in M81 has yielded one of the best determined distances for an external galaxy – 11.8 million light-years.


∞ Source: apod.nasa.gov/apod/ap190417.html


Thunder Egg 😃 | #Geology #GeologyPage #Mineral…


Thunder Egg 😃 | #Geology #GeologyPage #Mineral #ThunderEgg


Geology Page

www.geologypage.com

https://www.instagram.com/p/BwWNh0SAVAV/?utm_source=ig_tumblr_share&igshid=61te33hi2zdf


Rhodonite | #Geology #GeologyPage #Mineral Locality: North…


Rhodonite | #Geology #GeologyPage #Mineral


Locality: North Mine, Broken Hill, Yancowinna County, New South Wales, Australia


Dimensions: 2.5 × 2.2 × 1.4 cm


Photo Copyright © Crystal Classics


Geology Page

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https://www.instagram.com/p/BwWOr1GAVra/?utm_source=ig_tumblr_share&igshid=1sryp6dvitv78


the-beauty-of-napoli: Ganimede con l’aquila (II sec.), Museo Archeologico...

the-beauty-of-napoli:




Ganimede con l’aquila (II sec.), Museo Archeologico Nazionale, Napoli.



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the-beauty-of-napoli: Flora, Medea, Diana e Leda (I sec.), Museo Archeologico Nazionale,...

the-beauty-of-napoli:











Flora, Medea, Diana e Leda (I sec.), Museo Archeologico Nazionale, Napoli.



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the-beauty-of-napoli: Mosaico delle colombe (149-100 a. C.), Museo Archeologico...

the-beauty-of-napoli:




Mosaico delle colombe (149-100 a. C.), Museo Archeologico Nazionale, Napoli.



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Scientists say world’s protected areas need a re-boot

An international study published in the journal Science argues that the current international target for the protected area estate, accepted by over 190 nations, is failing. They propose a new measurable target based on the best scientific evidence that they say will galvanize greater and more effective conservation efforts.











Scientists say world's protected areas need a re-boot
This is a forest elephant, Nouabale Ndoki national Park, Republic of Congo
[Credit: Kyle de Nobrega]

The study identifies four major problems with the United Nation’s Aichi Target 11 — which calls for protection of at least 17 percent of terrestrial and inland water areas and 10 percent of coastal and marine areas. The authors say the target has led to perverse outcomes and has not fostered effective conservation efforts. The use of simple percentage targets for protected areas means that there is an incentive to create large protected areas of little conservation value. Other problems with Aichi Target 11 design and implementation include the lack of incentives in the target and resources dedicated to adequately manage or fund protected areas, inadequate representation of natural communities and species within protected area borders, and the impossibility to define national responsibilities towards the global target in a meaningful way.


Lead author Dr. Piero Visconti of the International Institute for Applied Synthesis Analysis, said: «While there has been a significant increase in the overall extent of the global protected area estate over the past 10 years, many of the new protected areas are being placed in sites that are not as important for biodiversity. Other, more important sites are left unprotected and are vanishing before our eyes. There is also clear evidence that the vast majority of protected areas are not being funded and managed in ways that stop damaging human activities.»


The study’s authors argue that outcome-based targets for protected areas are needed to achieve biodiversity goals. They propose the following new target: «The value of all sites of global significance for biodiversity including key biodiversity areas is documented, retained and restored through protected areas and other effective area-based conservation measures.»


The proposed target puts the emphasis on measuring and achieving the end-goal of conservation: reaching and maintaining long-term positive biodiversity status and trends. This is a critical step forward from all previous protected area commitments, which measured progress based on the amount of area protected, not the biodiversity outcomes resulting from it.


Despite the calls for a new protected area target, a co-author in the study Dr. James Watson of University of Queensland and the Wildlife Conservation Society (WCS), emphasized the critical importance of existing protected areas for safeguarding imperiled biodiversity.


Said Watson: «We know protected areas work—when well-funded, well-managed and well placed, they are extremely effective in halting the threats that cause biodiversity loss and ensure species return from the brink of extinction. There are also many protected areas that are still in good condition and are now the last strongholds for endangered species worldwide. The challenge is to improve the management of those protected areas that are most valuable for nature conservation to ensure they safeguard it.»


Added Watson: «We need all nations to be honest when accounting for how much land and water they have set aside for biodiversity conservation. As we approach the 2020 deadline for the Convention for Biological Diversity’s current targets, it is time for the global conservation community to stand up and hold governments to account so that they take the conservation of their protected areas seriously. This means setting a target that will achieve the outcome that is best for biodiversity.»


Source: Wildlife Conservation Society [April 11, 2019]



TANN



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cma-japanese-art: Wisdom King of Passion (Aizen myōō), 1300,…


cma-japanese-art:



Wisdom King of Passion (Aizen myōō), 1300, Cleveland Museum of Art: Japanese Art


The Buddhist deity Aizen channels carnal desire into a lust for spiritual enlightenment, and is an appropriation of the Hindu deity Rāgarāja. In its principal right arm this figure once held a vajra to cut through illusion, while its main left arm still grasps the vajra bell rung to bring one to awareness. The other arms grasped a lotus bud symbolizing the power of the Buddhist teachings, and a bow and arrow, borrowed from Kama, the Hindu god of love. The lion’s head in Aizen’s hair holds its mouth open so that it may be fed thoughts and desires. Traces of the red pigment that covered the deity’s body remain. Holes along the front of the legs show where the sculpture’s base, a lotus pedestal placed upon an urn spewing wish-fulfilling jewels, would have been attached.
Size: Overall: 75 x 59 x 35 cm (29 ½ x 23 ¼ x 13 ¾ in.)
Medium: wood, with black lacquer and red pigments


https://clevelandart.org/art/1987.185



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cma-japanese-art: Five-pronged Vajra Pestle (Gokosho), 900,…


cma-japanese-art:



Five-pronged Vajra Pestle (Gokosho), 900, Cleveland Museum of Art: Japanese Art


Resembling weapons wielded by deities described in the Vedas, ancient Indian religious scriptures, the vajra pestle (kongōsho) has long been used in Esoteric Buddhist rituals. The word vajra means diamond and thunderbolt in Sanskrit. Vajras are thus indestructible and powerful tools of Buddhism. The number of prongs has significance, with single-, three-, and five-pronged vajras being used for different purposes. The stylized thunderbolt known as a vajra also connotes the speed of lightning and the indestructible qualities of diamond to best describe the attributes of Tantra. Vajras are ubiquitous in tantric art and ritual practices. This example from the Heian period (784-1185) reveals the early spread of Tantra from India across China and Southeast Asia to enter Japan where it is known as Shingon. A Japanese monk named Kūkai founded the Shingon sect of Esoteric Buddhism after he received the texts and teachings from a Chinese tantric master. When he returned to Japan in 806, he founded the influential Shingon sect.
Size: Overall: 15 cm (5 7/8 in.)
Medium: bronze


https://clevelandart.org/art/1954.785



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met-greekroman-art: Terracotta alabastron (perfume vase) by…


met-greekroman-art:



Terracotta alabastron (perfume vase) by Persephone Painter, Greek and Roman Art


Rogers Fund, 1908

Metropolitan Museum of Art, New York, NY
Medium: Terracotta


Source


How Are Diamonds Cut?…


How Are Diamonds Cut? http://www.geologypage.com/2019/04/how-are-diamonds-cut.html


Humans are not off the hook for extinctions of large herbivores – then or now

What triggered the decline and eventual extinction of many megaherbivores, the giant plant-eating mammals that roamed the Earth millions of years ago, has long been a mystery. These animals, which weighed 1,000kg or more and included the ancient relatives of modern elephants, rhinos, hippos and giraffes, reached a peak of diversity in Africa some 4.5m years ago during the Pliocene epoch (between 5.3m and 2.6m years ago). After this, their numbers slowly declined, in a trend that continued into the Pleistocene (2.6m years ago to roughly 11,000 years ago).











Humans are not off the hook for extinctions of large herbivores – then or now
Hippos at Gorongosa National Park [Credit: Brett Kuxhausen]

Both the Earth’s climate and hominins – our early human ancestors – have in the past been blamed for this change. However, a recent paper argued that the gradual extinction of megaherbivores occurred because of long-term environmental changes and that developments in hominin behaviour – such as wielding tools and using fire – did not impact megaherbivore decline.
While this seems to be true of the early decline in megaherbivore population, we argue that our ancient human ancestors may well still have contributed to more recent megaherbivore extinctions. What’s more, we’re repeating the pattern today.


Ancient hominins in a land of giants


The genus Australopithecus is among the best known hominins from the Pliocene. Dating as far back as 4.2m years, they shared food and water-rich woodland and grassland environments with a dozen species of large herbivores, including three giraffids, two hippostwo species of rhinoceros and five species of proboscideans – a trunked and tusked group of animals that includes modern elephants and extinct mammoths and mastodons.


Australopithecus were omnivorous – but there is no evidence that they hunted large mammals. In fact, its likely that megaherbivores played a beneficial ecological role for these early hominins. Thousands of years of grazing and migration gradually opened up wooded environments, which created the perfect blend of woodland and grassland in which early hominins thrived. In these Pliocene landscapes, our ancestors and the ancestors of modern elephants, rhinos, giraffes and hippos coexisted in relative harmony.











Humans are not off the hook for extinctions of large herbivores – then or now
Kanapoi, Kenya, where 4.2m year old Australopithecus was found [Credit: Rene Bobe]

However, major climatic and environmental changes were to separate the fates of hominins and megaherbivores. Starting in the late Miocene epoch (the period just before the Pliocene), and continuing into the Pliocene and subsequent Pleistocene, ocean waters started cooling, atmospheric CO2 started decreasing and, in eastern Africa, grasslands began expanding, reducing woodland cover. There is also evidence of increasingly frequent fires.
Early hominins such as Australopithecus, comfortable in both grassland and woodland environments, were well-adapted to these changing climatic and environmental conditions, as shown by their rich fossil record at several sites in Africa. However, megaherbivore species that were only comfortable in wooded environments struggled to survive.


Changing behaviour of hominins


By the time more sophisticated hominins such as Homo erectus emerged 1.8m years ago, megaherbivores had already been in decline for more than two million years, according to the recent study’s authors. But that doesn’t mean that Homo erectus didn’t hammer the final nails into the collective megaherbivore coffin. We believe that current archaeological records are too poor to document the effects that hominin behavioural innovations such as tool use had on large mammal extinctions in the Pleistocene period.


For example, we don’t know how the early use of fire – likely as much as 1.5m years ago – influenced landscapes and foraging patterns of large herbivores. There is also no clear indication as to when hominins started hunting large herbivores. Could they have hunted large mammals during droughts, as some carnivores do today? We believe that the question of what role hominins such as Homo erectus had in the decline of megaherbivores remains open, despite the recent study’s findings.











Humans are not off the hook for extinctions of large herbivores – then or now
Gorongosa National Park [Credit: Brett Kuxhausen]

As we approach more recent periods of Earth history, there’s strong evidence that our species, Homo sapiens, played a major role in the wave of global megaherbivore extinctions that occurred toward the end of the Pleistocene era, between about 50,000 and 10,000 years ago. By this time, hominins were expanding over much of the globe and had become sophisticated hunters of large animals. It was during this period that species of mastodons, woolly rhinos and giant ground sloths, among many others, were finally wiped out.


A new wave of extinction


Of course, in modern times, humans are responsible for causing such profound biodiversity losses that we may be undergoing a “sixth mass extinction”, a calamity comparable to the worst biodiversity crises in Earth’s long history of 4.5 billion years. The current evidence shows that human encroachment and hunting are collapsing the natural environments of large herbivores such as elephants, rhinos, giraffes and hippos, sending their populations spiralling into decline.


But in the sea of bad news of ongoing extinctions and habitat degradation, there are some islands of hope that all is not lost. At the southern end of East Africa’s Great Rift Valley, Gorongosa National Park in Mozambique is witnessing a renaissance of biodiversity, with populations of elephants, hippos and other mammals actually increasing. Gorongosa shows us that with long-term planning and collaboration with local populations it is not too late to allow degraded ecosystems to recover and that – if given the opportunity – nature has an astonishing capacity for resilience.


Understanding the current biodiversity crisis from the perspective of deep time may help guide our efforts to conserve and restore the ecosystems we need for our own survival. Modern species of elephants, hippopotamuses, giraffes and rhinoceroses are survivors from the deep past. Elephantids appeared in the fossil record of eastern Africa at about the same time as the first hominins and probably helped to shape the landscapes where our hominin ancestors thrived. It is paradoxical that the single surviving hominin species is now driving modern-day megaherbivores, along with many other forms of life, to extinction. We do so at our peril.


Authors: Rene Bobe & Susana Carvalho | Source: The Conversation [April 11, 2019]



TANN



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Conservationists discover hidden diversity in ancient frog family

Research scientists led by the University of Kent have uncovered hidden diversity within a type of frog found only in the Seychelles, showing that those on each island have their own distinct lineage.











Conservationists discover hidden diversity in ancient frog family
Metamorph Sooglossus sechellensis balanced on a 10 pence coin
[Credit: Dr. Jim Labisko]

The family tree of sooglossid frogs dates back at least 63 million years. They are living ancestors of those frogs that survived the meteor strike on earth approximately 66 million years ago, and their most recent common ancestor dates back some 63 million years, making them a highly evolutionarily distinct group.


However, recent work on their genetics led by Dr Jim Labisko from Kent’s School of Anthropology and Conversation revealed that until they can complete further investigations into their evolutionary relationships and verify the degree of differentiation between each island population, each island lineage needs to be considered as a potential new species, known as an Evolutionarily Significant Unit (ESU). As a result, Dr Labisko advises conservation managers they should do likewise and consider each as an ESU.


There are just four species of sooglossid frog; the Seychelles frog (Sooglossus sechellensis), Thomasset’s rock frog (So. thomasseti), Gardiner’s Seychelles frog (Sechellophryne gardineri) and the Seychelles palm frog (Se. pipilodryas).


Of the currently recognised sooglossid species, two (So. thomasseti and Se. pipilodryas) have been assessed as Critically Endangered, and two (So. sechellensis and Se. gardineri) as Endangered for the International Union for Conservation of Nature IUCN Red List. All four species are in the top 50 of ZSL’s (Zoological Society of London) Evolutionarily Distinct Globally Endangered (EDGE) amphibians.


Given the Red List and EDGE status of these unique frogs Dr Labisko and his colleagues are carrying out intensive monitoring to assess the level of risk from both climate change and disease to the endemic amphibians of the Seychelles.


Dr Labisko, who completed his PhD on sooglossid frogs at Kent’s Durrell Institute of Conservation and Ecology in 2016 said many of these frogs are so small and good at hiding the only way to observe them is by listening for their calls. Although tiny, the sound they emit can be around 100 decibels, equivalent to the sound volume of a power lawnmower’.


Dr Labisko’s team are using sound monitors to record the vocal activity of sooglossid frogs for five minutes every hour, every day of the year, in combination with dataloggers that are sampling temperature and moisture conditions on an hourly basis


Dr Labisko said: ‘Amphibians play a vital role in the ecosystem as predators, munching on invertebrates like mites and mosquitos, so they contribute to keeping diseases like malaria and dengue in check. Losing them will have serious implications for human health.’


As a result of this study into the frogs, the research team will also contribute to regional investigations into climate change, making a local impact in the Seychelles.


Amphibians around the world are threatened by a lethal fungus known as chytrid. The monitoring of these sooglossid frogs will provide crucial data on amphibian behaviour in relation to climate and disease. If frogs are suddenly not heard in an area where they were previously, this could indicate a range-shift in response to warming temperatures, or the arrival of disease such as chytrid — the Seychelles is one of only two global regions of amphibian diversity where the disease is yet to be detected.


It may also impact on a variety of other endemic Seychelles flora and fauna, including the caecilians, a legless burrowing amphibian that is even more difficult to study than the elusive sooglossids.


Researchers know that caecilians can be found in similar habitats to the frogs, so they can use the frog activity and environmental data they are collecting to infer caecilian presence or absence and generate appropriate conservation strategies as a result.


The findings are published in the Biological Journal of the Linnean Society.


Source: University of Kent [April 11, 2019]



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Ice Ages occur when tropical islands and continents collide

University of California scientists think they know why Earth’s generally warm and balmy climate over the past billion years has occasionally been interrupted by cold snaps that enshroud the poles with ice and occasionally turn the planet into a snowball.











Ice Ages occur when tropical islands and continents collide
Mt. Bromo on the island of Java, Indonesia. An ongoing collision between a continental plate and this arc of volcanic
islands is exposing rocks that take up carbon dioxide from the atmosphere, which tends to cool Earth.
In earlier eras, such collisions in the tropics led to global ice ages
[Credit: Sara Marlowe, WikiCommons]

The key trigger, they say, is mountain formation in the tropics as continental land masses collide with volcanic island arcs, such as the Aleutian Islands chain in Alaska.


Earth’s climate is, to a large degree, driven by the amount of carbon dioxide in the atmosphere, which traps heat and warms the planet. While fossil fuel burning since the Industrial Revolution has driven CO2 levels to heights not seen in 3 million years, CO2 levels have been even higher in Earth’s past, coinciding with warm periods when no major ice sheets existed.


In fact, Earth’s default climate seems to be warm and balmy. Periods with no glaciers dominated for three-quarters of the past 1 billion years.


Yet, half a dozen ice ages chilled Earth during that time, two of them severe enough to turn the planet into a Snowball Earth with ice covering much of the surface. What caused these frigid interludes?











Ice Ages occur when tropical islands and continents collide
Plate tectonics shifted the continents around over the past 500 million years, inevitably causing collisions.
When collisions with volcanic island arcs occurred in the tropics (green band), they exposed rocks
called ophiolites (orange), which sucked up carbon from the atmosphere and led to
ice formation (blue) and global cooling [Credit: Nicholas Swanson-Hysell]

In a study appearing in this week’s edition of the journal Science, the team concludes that when volcanic arcs collide with continents in the tropics — an inevitable consequence of the planet’s constantly moving tectonic plates — they trigger global cooling, resulting in a glacial climate with extensive ice caps.
Such a collision is going on now as parts of the Indonesian archipelago are pushed upward into mountains on the northern margin of Australia. The result is that there are mountains containing rocks known as ophiolites that have a high capacity to remove carbon from the atmosphere. Over geologic time periods, there is a balancing act between the CO2 emitted from volcanoes and CO2 consumed through chemical reactions with rocks. Rocks with abundant calcium and magnesium, such as ophiolites, are the most efficient at consuming CO2. When these elements are liberated from rocks, they combine with CO2 and make their way to the ocean, where they form limestone, locking CO2 into rock, where it remains for millions of years.


«Earth has a long-running carbon sequestration program,» said UC Berkeley’s Nicholas Swanson-Hysell, an assistant professor of earth and planetary science who designed the study with Francis Macdonald, a professor in the Department of Earth Science at UC Santa Barbara. «We know that these processes keep Earth’s climate in balance, but determining what causes shifts between non-glacial and glacial climates on million-year timescales is a long-standing puzzle.»











Ice Ages occur when tropical islands and continents collide
Over most of the last billion years, Earth has had little to no ice (white regions). However, ice has extended from
the poles southward at least seven times, including today (blue), and twice covered nearly all of the planet
[Credit: Nicholas Swanson-Hysell]

Unfortunately for Earth’s future, the geologic processes that consume CO2 are slow and unable to contend with the massive CO2 emissions that result from the burning of oil, coal and natural gas. Over millennia, Earth’s natural carbon sequestration program will restore balance, Swanson-Hysell said, but this will be a long wait for modern civilization, which has been so successful in Earth’s current, cooler climate.


The Appalachians came with a major freeze


In 2017, Swanson-Hysell and Macdonald proposed that a major ice age 445 million years ago was triggered by a collision similar to that occurring today in Indonesia. That collision took place during the first phase of Appalachian mountain-building, when the present-day eastern U.S. was located in the tropics. In the warm and wet tropics, the weathering reactions that ultimately sequester carbon are even more efficient, which resulted in less CO2 in the atmosphere and a cooler planet for millions of years. The UC researchers’ work built on a similar proposal by Macdonald and Oliver Jagoutz of MIT that such processes were important for cooling over the past 90 million years.











Ice Ages occur when tropical islands and continents collide
Some 445 million years ago, the Eastern U.S. (extreme left) sat in the tropics, where an island arc-continental collision
created the Appalachian Mountains. That collision resulted in an ice age that lasted millions of years
[Credit: Nicholas Swanson-Hysell]

The new study strengthens the link between such tropical collisions and global climate and was conducted by Swanson-Hysell, Macdonald and Jagoutz, along with UC Berkeley graduate student Yuem Park and Lorraine Lisiecki of UC Santa Barbara.


In the current research, the Berkeley/Santa Barbara/MIT team used state-of-the-art models of Earth’s paleogeography to reconstruct the position of such mountain-building events over the last half-billion years. They found that all three major ice ages over this time had been preceded by volcanic arc-continent collisions in the tropics, and that no collisions outside the tropics triggered an ice age.


«While we thought this process was important, the relationship between such environments in the tropics and glacial climate was clearer than we expected,» said Swanson-Hysell.


The team’s theory also explains why ice ages come to an end. As such collisions grind to a halt and less rock is exposed, or as the rocks drift out of the tropical rain belt, carbon sequestration becomes less efficient, CO2 levels rise as volcanic outgassing continues and Earth once again warms into a non-glacial climate.


Author: Robert Sanders | Source: University of California — Berkeley [April 11, 2019]



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