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Curiosity rover: 2,000 days on Mars

Nasa’s Curiosity rover, also known as the Mars Science Laboratory (MSL), is celebrating 2,000 martian days (sols) investigating Gale Crater on the Red Planet. In that time, the robot has made some remarkable observations. Here are just a few of them, chosen by the Curiosity science team.

Looking back: In the history of the space age, some of the most dramatic planetary images ever taken have been of Earth, but photographed looking back from deep space. This image by Mastcam on the Curiosity Rover shows our planet as a faint pinpoint of light in the martian night sky. Every day scientists from across the world drive the Curiosity rover and study the Red Planet about 100 million miles from Earth.

 

 

The beginning: The first image that Curiosity took came back just 15 minutes after landing on 5 August 2012. Getting our imagery and other data relies on the timing of Mars Reconnaissance Orbiter (MRO) overpasses, a pattern which determines the structure of the martian working day, or sol. It shows a grainy Front Hazard Camera image – the team normally use these to help avoid obstacles – of our ultimate goal Mount Sharp. When this image came back we knew it was going to be a successful mission.

 

River pebbles: Once we had started driving (16 sols after landing), we soon came across these pebble beds. The rounded shape of the clasts shows that they formed in an ancient, shallow river, flowing from the surrounding four-billion-year-old highlands into Gale Crater. The inset Mastcam image shows one of the pebbles in close-up. Contrary to our expectations before MSL, the crust being eroded by the rivers was not all dark, primitive basalt but a more evolved composition and mineralogy. Pebbles caught up in this ancient martian river are causing us to rethink our view of how the underlying igneous crust and mantle of Mars formed.

 

Ancient lake: Before landing and in the early part of the mission, the team wasn’t sure what all of the terrains identified from MRO HiRISE orbital imagery were. They might have been lava flows or lake sediments, without close-up “ground truth” it was impossible to be certain. This image settled the debate and was a seminal stage in Martian exploration. Yellowknife Bay is made of layers of fine grained sand and muds, which were deposited as rivers flowed into an ancient Gale Crater lake. We made our first of 16 drill holes on sol 182 – we do this to get rock in to the spectrometers housed in the body of our rover – here at the John Klein site. The results – including identifying clays, organics and nitrogen-bearing compounds – showed us that this had been a habitable environment for microbial life. The next discovery step – Was There Life? – remains to be determined.

 

Deep water: The Pahrump Hills section Curiosity encountered around sol 753 was key for developing our understanding of Gale’s past environment. Here the rover observed thinly layered mudstones, which represented mud particles settling out from suspension within the deeper lake. The Gale Lake has been a long-standing, deep body of water.

An unconformity: At Mount Stimson, the rover identified from sol 980 a thick sandstone unit overlying the lake deposits, separated by a geological feature called an unconformity. This unconformity represents a time where erosive processes took over after millions of years when the lake had finally dried up – to form a new land surface. This shows evidence of events happening over “deep time”, similar to those that the pioneering geologist James Hutton described in his field work in the late 18th Century at Siccar Point on the Scottish Coast.

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Bagnold dune fieldImage copyrightNASA/JPL-CALTECH/MSSS

Desert sands: The Namib dunes encountered close up by Curiosity at sol 1192 is a small part of the great Bagnold dune field. Its the first active dunefield explored on the surface of another planet and Curiosity had to pick its way carefully along and through the field as moving sands are an obstacle for rovers. Although the Martian atmosphere is a fraction of the density of that of Earth’s, it is still capable of transporting sediment and is capable of creating such beautiful structures akin to those we see in the deserts of Earth.

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Murray ButtesImage copyrightNASA/JPL-CALTECH/MSSS

Wind sculptures: The Murray Buttes, photographed by Mastcam on sol 1448, formed of the same sandstones observed at Mount Stimson and represent a lithified dune field created by dunes similar to those in the present day Bagnold dune field. These desert-formed sandstones sit above an unconformity, and this suggests that after a long period with a humid climate, the climate became drier and wind became the dominant agent shaping the environment at Gale Crater.

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Ancient mudcracksImage copyrightNASA/JPL-CALTECH/LANL/CNES/IRAP/LPGNANTES/CNRS/IAS

Dried muds: Curiosity is able to perform detailed analyses of the Gale rocks with the ChemCam laser and telescope mounted on its mast. Here on sol 1555 at Schooner Head we came across a set of ancient mudcracks and sulphate veins. On Earth, lakes typically dry up in places around their margins and here on Mars the Gale lake was no different. You can see the red crosses where we fired the laser at the rock, creating a small plasma spark, with the wavelength of light in the spark telling us the composition of the mudstone and veins.

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CloudsImage copyrightNASA/JPL-CALTECH

Cloudy skies: This sequence of images was taken with Curiosity’s Navigational Cameras (NavCam) on sol 1971 as we pointed them towards the sky. Occasionally on the cloudiest of Martian days we are able to make out faint clouds in the sky. These images are processed to highlight differences, allowing us to see the clouds move across the sky. This sequence shows previously unseen cloud features with prominent zig-zag patterns visible. The three images, from start to finish, cover approximately 12 minutes on Mars

 

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Human Anatomy and Physiology: The Blood Vessels and the Heart
Supply Chain Management Model

In general there are three types of blood vessels: arteries, veins and capillaries. Given an artery and a vein with similar inner diameters, the artery will have a thicker wall than the vein. Capillary walls have only one layer-the intima.

The nutrient blood supply provides blood through the usual exchange of materials between body cells and the blood. A collateral circulation is a special organization of blood vessels around a major joint or other area of the body. There are areas of the body where a single artery is the sole supply of blood, such an artery is called an end artery.

End arteries are most common in the brain and the heart. A portal vein is a venous blood vessel that begins with capillaries in one area and ends in capillaries or another area. The most important portal vein in the human body is the Hepatic Portal Vein.

For protection, arteries tend to be located deep within the structures of the body. Veins can be located at both deep and cutaneous levels. The capillaries are located throughout all tissues of the body. The networks of capillaries in the tissues are often called capillary beds.

The capillary beds make up the greatest cross-sectional area of the cardiovascular system. The wall of the capillary consists of a single layer of flat cells. The capillary beds are provided with pre-capillary sphincters that can reduce or completely stop the flow of blood into the capillaries.

The heart consists of four separate chambers. The two chambers at the top of the heart are called atria (singular: atrium). Down the middle of the heart, an interatrial septum separates the two atria. The two chambers at the bottom of the heart are called ventricles. Between the ventricles is a wall of tissue separating the left and right ventricles, this is called the interventricular septum. The walls of the chambers of the heart consist of three layers: the myocardium, the endocardium, and the epicardium, also known as the visceral pericadium. The chambers themselves are linked with a simple epithelium known as the endocardium.

By far the  most important of the three layers in the heart walls is the myocardium, the middle layer. The myocardium is thicker in the walls of the ventricles than the atria. The stroke volume is the amount of blood forced out of each ventricle in one contraction. The cardiac output is the volume of blood pumped out of the ventricles (right into the lungs, left into the systemic circulation) in one minute (expressed in liters per minute). Valves are structures that ensure that fluids will pass through them in one direction only. There are two sets of cardiac valves-the atrioventricular (AV) valves and the semilunar valves. The AV valves are found between the atria and the ventricles.

Chordae tendineae are a special anatomical arrangement which help prevent the backward flow of blood into the atria. When the ventricles contract (ventricular systole) and the AV valves have closed, the blood moves out into the great arteries through the aortic and pulmonary semilunar valves. When the ventricles relax (ventricular diastole), the back pressure of the blood in the great arteries forces the cusps of the semilunar valves to the center and seals off each opening. The NAVL of the heart are the nerves, arteries, veins and lymphatics which influence the actions of the heart.

Control of heart functions can be divided into the following areas: Extrinsic controls (control from outside the heart), Intrinsic controls (control from inside the heart), and Humoral control, where some substances transported by the blood can accelerate or slow the action of the heart. The sinoatrial (SA) node is a collection of impulse conducting fibers in the interatrial septum. The atrioventricuar (AV) node is a group of impulse conducting fibers just above the interventricular septum. Fibers descend from the AV node to form the Bundle of His, which branches into the right and left septal bundles. The septal bundles connect with the Purkinje fibers located throughout the ventricular walls. Impulses begin in the SA node, pass to the AV node, and then descend through the septal bundles and on the Purkinje fibers to stimulate the myocardium of the ventricular walls to contract.

The blood which supplies the heart tissue itself is called nutrient blood. The openings leading into the coronary arteries are located in the base of the ascending aorta, just above the semilunar valve ( Aortic valve). Many of the branches of the coronary arteries are of the end artery type. The blood from the tissues of the heart is collected by the cardiac veins. The Thesbian veins are many minute sinuses found in the myocardium of the ventricles.

There is a fibrous connective tissue structure within the substance of the heart. Each atrioventricular valve of the heart is surrounded by a dense fibrous ring. Each of the semilunar valves of the heart is located within a short fibrous cylinder. The fibrous pericardium is a very dense fibrous envelope. the parietal pericardium is the outer serous membrane. the visceral pericardium intimately covers the surface of the heart.

Blood is driven through the arteries by a combination of forces. When the left ventricle contracts-systole, it forces the blood into the aortic arch. When the ventricle relaxes-diastole, the wall of the aortic arch recoils and presses against the blood. Vasoconstriction is the actual contraction of the arterial walls. In the head and neck, gravity helps to move the blood down through the veins.

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Doubts raised over Australia’s plan to release herpes to wipe out carp

An Australian plan to kill invasive carp by releasing a virus into waterways has come under fire from researchers who argue that the tactic will not eradicate enough fish.

Australia has fought for decades to control populations of the common carp (Cyprinus carpio), and in 2016 the government invested Aus$15 million (US$11.7 million) in a plan to investigate the virus approach. The proposal is to infect carp with a strain of herpes called CyHV-3, which has caused mass fish deaths in the United States and Japan.

Many researchers have previously warned of possible far-reaching consequences of the plan, including rivers clogged with decaying fish corpses and further disruption to native ecosystems. Now, six researchers argue in a letter published in Science1 on 22 February that the virus is unlikely to be effective.

They contend that more data — including some from field trials — are needed before a wide-scale release of the virus. “This is potentially a big ecological move that’s being made on not enough data,” says Philip Stevenson, a virologist at the University of Queensland in Brisbane and a co-author of the letter. The other authors include Jonathan Marshall, a member of the science advisory board of the National Carp Control Plan (NCCP), which is managing and conducting research into the potential virus release.

The NCCP’s coordinator, Matt Barwick, says that he welcomes debate about the proposal, but he adds that the NCCP has already addressed the issues raised in the letter or has submitted research proposals to do so to its scientific advisory board. “It’s accurate that we need to confirm the likely efficacy, and that’s exactly what we’re doing,” he says.

Carp carnage

The common carp was first introduced to Australia from Europe in the nineteenth century, but the biggest disruptions to ecosystems happened after a particularly hardy strain escaped from a fish farm in the early 1960s. With a single fish capable of producing more than one million eggs in a breeding cycle, carp now make up an estimated 80–90% of the fish biomass in parts of the Murray–Darling Basin, the breadbasket region of southeast Australia. Carp feed on the river bottom, which stirs up sediment and reduces water clarity, hurting native aquatic plants and animals. The economic impact of the fish is estimated at Aus$500 million a year.

In 2016, the Australian government launched the NCCP to study and design a potential release of CyHV-3. Led by the Fisheries Research and Development Corporation, an Australian authority, the group tested the effects of the virus on animals including 13 native fish species, as well as chickens, mice, frogs and turtles, and concluded that it is safe for them. The virus is only known to affect the common carp and ornamental koi, in which the expected mortality rate is over 70%.

However, the Science letter says that the virus’s effectiveness depends on environmental factors, and that the disease develops only when water temperatures are between 16 ºC and 28 ºC. Populations of carp that survive the initial viral epidemic in hot or cold spots would be able to replenish the population quickly, say the authors.

Ken McColl, a research veterinary pathologist at Australia’s Commonwealth Scientific and Industrial Research Organisation in Geelong, and one of the lead researchers on the carp herpesvirus project, says the NCCP is currently assessing environmental factors through outbreak simulations that take into account regional water conditions and climate. It is also considering a field trial to assess the technique, says Barwick. The NCCP intends to publish its completed risk assessment by the end of 2018. The ultimate decision on whether to go ahead with the plan will be made by Australia’s environment minister; the earliest possible date for the virus to be released would be late 2019, says Barwick.

In the Science letter, Stevenson and his co-authors raised the prospect that the virus could already be present in Australia. If so, releasing it again would have little effect. Barwick says that question will be addressed by a proposed programme to sequence the genomes of wild-caught carp. The programme will also examine whether other viruses already present in Australian carp could react with CyHV-3 and provide immunity to it.

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Neanderthal artists made oldest-known cave paintings

 

Neanderthals painted caves in what is now Spain before their cousins, Homo sapiens, even arrived in Europe, according to research published today in Science. The finding suggests that the extinct hominids, once assumed to be intellectually inferior to humans, may have been artists with complex beliefs.

Ladder-like shapes, dots and handprints were painted and stenciled deep in caves at three sites in Spain. Their precise meaning may forever be unknowable, says Alistair Pike, an archaeologist at the University of Southampton, UK, who co-authored the study, but they were almost certainly meaningful to our lost kin. “It wasn’t simply decorating your living space,” Pike says. “People were making journeys into the darkness.”

Humans are thought to have arrived in Europe from Africa around 40,000–45,000 years ago. The three caves in different parts of Spain yielded artworks that are at least 65,000 years old, according to uranium-thorium dating of calcium carbonate that had formed on top of the art.

These mineral deposits develop slowly, as water containing calcium comes into contact with cave surfaces. The water also contains trace levels of uranium from the rock. After the calcium carbonate has precipitated out of the water, a clock of sorts begins to tick, as uranium decays into thorium at a steady, known rate.

Uranium-thorium dating has been used in geology for decades, but has seldom been employed to estimate the age of cave art. Some archaeologists are sceptical of the approach. They suggest that the calcium carbonate could have dissolved and re-crystallized after it was first formed — a process that could have also washed away some uranium, making a sample of the mineral appear older than it is.

Until now, the oldest known cave art was roughly 40,000 years old — stenciled hands and animals in an Indonesian site that was dated in 2014, and discs and hand stencils from a cave in Cantabria, Spain, that were found by Pike and his colleagues in 2012.

Drawing conclusions

Anticipating objections about its dating method, Pike’s team collected samples from the outer, middle and inner layers of the calcium carbonate crust and dated them separately. As they expected, the inner samples closest to the art yielded the oldest dates, and the outer samples had younger dates because they would have been later layers of precipitate. “We can’t think of any processes that would re-crystalize the calcite and still keep them in stratigraphic order,” Pike says. The researchers waited three years to publish their results after finding their first clearly pre-human date so they could collect multiple examples and publish their methodology.

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8 Mind-Blowing Facts About Space – Mashable

Image: Flickr, NASA Goddard Space Flight Center
When you look up at the stars, what do you think about? That we may be not be alone? The vastness of it all?

There’s a lot to wonder about space. The fact is we don’t know all the answers about it. We know it’s vast and beautiful, but we’re not really sure how vast (or how beautiful, for that matter).

Some of the things we do know, however, are downright mind-boggling. Below, we’ve collected some of the most amazing facts about space, so when you look up at the stars you can be ever more wowed by what you’re looking at.

Though the study of astronomy predates recorded history, and physical space exploration has been possible since the 1950s, humans still remain largely in the dark about what’s really out there.

For all that we’ve discovered, astronomers estimate that nearly 96% of the universe remains impossible to see or even comprehend.

See also: 55 Astonishing Images of Earth From Space

But for all the mystery surrounding space, one thing we’re sure of is its staggering beauty. Telescopes like NASA’s Hubble illuminate the observable universe with captivating images of far-off planets, galaxies and star clusters.

Take in the beauty our universe has to offer through these 30 stunning images of space.

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11 Facts About Volcanoes And What Thay Do
  1. A volcano is a mountain that opens downward to a pool of molten rock below the surface of the earth. When pressure builds up, eruptions occur.
  2. In an eruption, gases and rock shoot up through the opening and spill over or fill the air with lava fragments. Eruptions can cause lava flows, hot ash flows, mudslides, avalanches, falling ash and floods.
  3. The danger area around a volcano covers about a 20-mile radius.
  4. Fresh volcanic ash, made of pulverized rock, can be harsh, acidic, gritty, glassy and smelly. The ash can cause damage to the lungs of older people, babies and people with respiratory problems.
  5. Volcanic lightning occurs mostly within the cloud of ash during an eruption, and is created by the friction of the ash rushing to the surface. Roughly 200 accounts of this lightning have been witnessed live.

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  1. An erupting volcano can trigger tsunamis, flash floods, earthquakes, mudflows and rockfalls.
  2. More than 80% of the earth’s surface is volcanic in origin. The sea floor and some mountains were formed by countless volcanic eruptions. Gaseous emissions from volcano formed the earth’s atmosphere.
  3. There are more than 500 active volcanoes in the world. More than half of these volcanoes are part of the “Ring of Fire,” a region that encircles the Pacific Ocean.
  4. Active volcanoes in the U.S. are found mainly in Hawaii, Alaska, California, Oregon and Washington, but the greatest chance of eruptions near areas where many people live is in Hawaii and Alaska.
  5. The sound of an eruption volcano can be quiet and hissing or explosive and booming. The loud cracks travel hundreds of miles and do the most damage, including hearing loss and broken glass.
  6. The most deadly eruptions have occurred in Indonesia, with tens of thousands of lives lost to starvation, tsunami (as a result of the eruption), ash flows, and mudflows.
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Human Anatomy and Physiology: Cardiovascular System

The cardiovascular system is the primary circulatory system of the human body. It’s main function is transport. It also provides protection against foreign substances. The arteries of this system generally carry blood from the chambers of the heart to the tissues of the body, while the veins carry blood from the tissues of the body to the chambers of the heart. The blood circulation is a two cycle system which involves both the pulmonary cycle and the systemic cycle. In the former, the pulmonary cycle, blood circulates from the heart to the lungs and back to the heart.

 

In simple organisms such as unicellular and one or two layer organisms, materials can be transferred among cells by simple processes of diffusion. However, in large organisms, a system is needed for the distribution and collection of materials. The circulatory system is used by the human body to carry substances. Some substances are collected from the body cells for elimination. The body also produces hormones which are the products of the endocrine glands.

 

Some of the liquids of the body are blood, lymph or cerebrospinal fluid. Some of the vessels of the body include the blood vessels and lymph vessels. Blood is composed of the following: plasma and formed elements. Plasma makes up about 55 percent of the total blood volume. Water is also a part of our body composition. It has an ample heat-carrying capacity. Along with dissolved salts, plasma proteins help to maintain the tonicity of the plasma. Fibrinogen is important to blood clotting. The percentage by volume of red blood cells in the blood is called haematocrit. Haemoglobin, a special protein, is found within red blood cell cytoplasm. The normal, mature red blood cell is a biconcave disc. White blood cells are another of the formed elements of the blood, they are also known as leucocytes. There are several types of white blood cells including neutrophils, monocytes, phagocytes and lymphocytes. Platelets are also another type of formed element in the blood.

 

The blood is the vehicle for the cardiovascular system; it is used to transport substances around the body. Oxygen in the air fills the alveolus of the lung and carbon dioxide is produced during metabolic oxidation within the individual cell.

 

The blood carries glucose and oxygen around the body. When the hormone epinephrine is secreted by the Adrenal Gland, it is delivered to all parts of the body by the cardiovascular system. In periods when much energy is required, the body can use its stores of fat as a source of energy.

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is the best place to see the northern lights (aurora borealis)

The best places to see the northern lights

To experience the unbelievable colours that moves across the Arctic sky is on many travellers’ bucket list. Few places on earth offer more ways to witness the aurora borealis than Norway.

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One of the unsolved mysteries about the Atlantic : TRUE OR MYTH?

They mention that Atlantis was as big as a continent !!

A great archaeological discovery at the bottom of Lake Van in Turkey again lightens the scenarios for the lost Atlantis.

Platonas say it was an island located on the seabed of Gibraltar The existence of the hidden city in the Antarctic “confirmed” according to the absurd theory of an ancient map, known as the Piri Reis map, which allegedly written in 1513 AD

The letter to Christians explains how Atlantis was created and because it was circular like a ring, with a sea and a small island in the middle (just like the ancient Thira just before the big blast). “When the gods shared the earth, Neptune received Atlantis and handed it to the sons of the demigods to cultivate it. One of them married Lefkipi and they made Kleito, whom Poseidon fell in love with, and he wanted to make her forever. Then he chose a place and protected it with circular zones of fertile land and sea to ensure her heavenly life (as if we were seeing Crete along with the ancient Kallisti). ”

The name Atlantis is probably derived from the mythical giant Atlanta, which held the whole earth and the sky on its shoulders. According to the discoveries of American geologists Haiken and McKoy, made in Santorini in 1990, they all refer to the famous fresco found in the western building of Akrotiri. Here we see a beach of ancient Thira with a wealthy life on a central island that was drenched by the sea around. Just as he described Plato the lost Atlantis. And this islet is claimed to have disappeared from a major explosion that caused terrible earthquakes and smoke. According to Plato, the fumes were projected into the sky, 40 km high. If that was the case, then it certainly seemed to be on the shores of the Eastern and Central Mediterranean. People watched the nature’s rumors bewildering, seeing that they were watching Atlanta himself holding the sky on his shoulders.


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https://www.madata.gr/epikairotita/world/483492.html

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One of the unsolved mysteries about the Atlantic : TRUE OR MYTH?

They mention that Atlantis was as big as a continent !!

A great archaeological discovery at the bottom of Lake Van in Turkey again lightens the scenarios for the lost Atlantis.

Platonas say it was an island located on the seabed of Gibraltar The existence of the hidden city in the Antarctic “confirmed” according to the absurd theory of an ancient map, known as the Piri Reis map, which allegedly written in 1513 AD

The letter to Christians explains how Atlantis was created and because it was circular like a ring, with a sea and a small island in the middle (just like the ancient Thira just before the big blast). “When the gods shared the earth, Neptune received Atlantis and handed it to the sons of the demigods to cultivate it. One of them married Lefkipi and they made Kleito, whom Poseidon fell in love with, and he wanted to make her forever. Then he chose a place and protected it with circular zones of fertile land and sea to ensure her heavenly life (as if we were seeing Crete along with the ancient Kallisti). ”

The name Atlantis is probably derived from the mythical giant Atlanta, which held the whole earth and the sky on its shoulders. According to the discoveries of American geologists Haiken and McKoy, made in Santorini in 1990, they all refer to the famous fresco found in the western building of Akrotiri. Here we see a beach of ancient Thira with a wealthy life on a central island that was drenched by the sea around. Just as he described Plato the lost Atlantis. And this islet is claimed to have disappeared from a major explosion that caused terrible earthquakes and smoke. According to Plato, the fumes were projected into the sky, 40 km high. If that was the case, then it certainly seemed to be on the shores of the Eastern and Central Mediterranean. People watched the nature’s rumors bewildering, seeing that they were watching Atlanta himself holding the sky on his shoulders.


https://gr.pinterest.com/pin/237072367862016853/
https://www.madata.gr/epikairotita/world/483492.html

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