(Phys.org) —Monozygotic twins look more similar when they are young than later in life. One of the reasons for this is epigenetic change in the form of chemical modifications of the DNA or its packaging proteins.
Ολες οι αλλαγές στην πρωτοβάθμια φροντίδα υγείας - Ο ρόλος του οικογενειακού γιατρού - Οι υποχρεωτικές προληπτικές εξετάσεις -Τι θα ισχύει για τους χρονίως πάσχοντες - Πώς λειτουργούν τα Κέντρα Υγείας Αστικού Τύπου - Τι θα κάνουν οι ανασφάλιστοι
1. Εως σήμερα μπορούσα απευθείας να κλείσω ραντεβού και να επισκεφθώ είτε τον γιατρό του ΕΟΠΥΥ είτε να κλείσω ραντεβού σε συμβεβλημένο γιατρό του Ταμείου είτε να πάω σε μια εφημερία και ας είχα μικρό πρόβλημα. Επίσης, μπορούσα να κλείσω ραντεβού στα εξωτερικά ιατρεία νοσοκομείου. Τώρα τι θα πρέπει να κάνω;
"Google Drive is one of the fundamental tools in our digital toolkits as teachers and educators. Whether you want to compose a document, create a presentation, design a sheet, or share a beautiful drawing you made, Google Drive provides you with the tools to do that on any device and anywhere you are with an internet connection "
Το Βήμα Online Ο ιός του έρπητα «μαρτυρεί» τις μετακινήσεις του ανθρώπινου είδους Το Βήμα Online Οι έξι κλάδοι του ιού του επιχείλιου έρπητα HSV-1 σε σχέση με τις ανθρώπινες μετακινήσεις (Πηγή Aaron W.
....Τον 3ο αιώνα πριν από τη γέννηση του Χριστού, έλεγαν ότι η βιβλιοθήκη της Αλεξάνδρειας περιέκλειε στις αίθουσές της το σύνολο της ανθρώπινης γνώσης. Στις μέρες μας, ο όγκος των διαθέσιμων πληροφοριών είναι τόσο μεγάλος ώστε, αν τον μοιράζαμε εξίσου σε όλους τους Γήινους, καθένας θα λάμβανε μια ποσότητα δεδομένων τριακόσιες είκοσι φορές μεγαλύτερη από το σύνολο των περιεχομένων της αλεξανδρινής συλλογής....
Many researchers believe that physics will not be complete until it can explain not just the behaviour of space and time, but where these entities come from.
“Imagine waking up one day and realizing that you actually live inside a computer game,” says Mark Van Raamsdonk, describing what sounds like a pitch for a science-fiction film. But for Van Raamsdonk, a physicist at the University of British Columbia in Vancouver, Canada, this scenario is a way to think about reality. If it is true, he says, “everything around us — the whole three-dimensional physical world — is an illusion born from information encoded elsewhere, on a two-dimensional chip”. That would make our Universe, with its three spatial dimensions, a kind of hologram, projected from a substrate that exists only in lower dimensions.
This 'holographic principle' is strange even by the usual standards of theoretical physics. But Van Raamsdonk is one of a small band of researchers who think that the usual ideas are not yet strange enough. If nothing else, they say, neither of the two great pillars of modern physics — general relativity, which describes gravity as a curvature of space and time, and quantum mechanics, which governs the atomic realm — gives any account for the existence of space and time. Neither does string theory, which describes elementary threads of energy. Van Raamsdonk and his colleagues are convinced that physics will not be complete until it can explain how space and time emerge from something more fundamental — a project that will require concepts at least as audacious as holography.
But, where is the evidence that there actually is anything more fundamental than space and time? A provocative hint comes from a series of startling discoveries made in the early 1970s, when it became clear that quantum mechanics and gravity were intimately intertwined with thermodynamics, the science of heat. In 1974, most famously, Stephen Hawking of the University of Cambridge, UK, showed that quantum effects in the space around a black hole will cause it to spew out radiation as if it was hot. Other physicists quickly determined that this phenomenon was quite general. Even in completely empty space, they found, an astronaut undergoing acceleration would perceive that he or she was surrounded by a heat bath. The effect would be too small to be perceptible for any acceleration achievable by rockets, but it seemed to be fundamental. If quantum theory and general relativity are correct — and both have been abundantly corroborated by experiment — then the existence of Hawking radiation seemed inescapable.
A second key discovery was closely related. In standard thermodynamics, an object can radiate heat only by decreasing its entropy, a measure of the number of quantum states inside it. And so it is with black holes: even before Hawking's 1974 paper, Jacob Bekenstein, now at the Hebrew University of Jerusalem, had shown that black holes possess entropy. But there was a difference. In most objects, the entropy is proportional to the number of atoms the object contains, and thus to its volume. But a black hole's entropy turned out to be proportional to the surface area of its event horizon — the boundary out of which not even light can escape. It was as if that surface somehow encoded information about what was inside, just as a two-dimensional hologram encodes a three-dimensional image.
In 1995 then, Ted Jacobson, a physicist at the University of Maryland in College Park, combined these two findings, and postulated that every point in space lies on a tiny 'black-hole horizon' that also obeys the entropy–area relationship. From that, he found, the mathematics yielded Einstein's equations of general relativity — but using only thermodynamic concepts, not the idea of bending space-time. Ted's result suggested that gravity is statistical, a macroscopic approximation to the unseen constituents of space and time.
In 2010, this idea was taken a step further by Erik Verlinde, a string theorist at the University of Amsterdam, who showed that the statistical thermodynamics of the space-time constituents — whatever they turned out to be — could automatically generate Newton's law of gravitational attraction. In separate work, Thanu Padmanabhan, a cosmologist at the Inter-University Centre for Astronomy and Astrophysics in Pune, India, showed that Einstein's equations can be rewritten in a form that makes them identical to the laws of thermodynamics — as can many alternative theories of gravity. Padmanabhan is currently extending the thermodynamic approach in an effort to explain the origin and magnitude of dark energy: a mysterious cosmic force that is accelerating the Universe's expansion.
Η σημασία της βαθμολογίας τόσο για τη διαδικασία της διδασκαλίας όσο και για τα άτομα πού συμμετέχουν σ' αυτήν είναι προφανής. Για το λόγο αυτό ο δάσκαλος θα πρέπει να εισάγεται συστηματικά στη μελέτη των ...
For hamburgers that cost more than $300,000 to produce, you might expect fries and a shake too. But this is no ordinary burger being served to two volunteer taste-testers in London on Monday. This meat was grown in a laboratory from stem cells of cattle.
Mark Post, whose team at Maastricht University in the Netherlands developed the burger after five years of research, hopes that making meat in labs could eventually help solve the food crisis and fight climate change.
But Post says success doesn't hinge on science. "For the burger to succeed it has to look, feel and taste like the real thing," he said. The meat was made from cow muscle cells from two organic cows. The resulting patties will be seasoned with salt, egg powder, breadcrumbs, red beet juice and saffron.
Post and colleagues took muscle cells from a cow and put them into a nutrient solution to help them develop into muscle tissue. The muscle cells grew into small strands of meat, and it takes nearly 20,000 strands to make one 140-gram (5-ounce) burger.
The project cost 250,000 euros ($332,000)."I'm a vegetarian but I would be first in line to try this," said Jonathan Garlick, a stem cell researcher at Tufts University School of Dental Medicine in Boston. He has used similar techniques to make human skin but wasn't involved in the burger research.
Experts say new ways of producing meat are needed to satisfy growing carnivorous appetites without exhausting resources. By 2050, the Food and Agriculture Organization predicts global meat consumption will double as more people in developing countries can afford it. Breeding animals destined for the dinner table takes up about 70 percent of all agricultural land.
The animal rights group PETA has thrown its support behind the lab-meat initiative. "As long as there's anybody who's willing to kill a chicken, a cow or a pig to make their meal, we are all for this," said Ingrid Newkirk, PETA's president and co-founder. "Instead of the millions and billions (of animals) being slaughtered now, we could just clone a few cells to make burgers or chops."
(Phys.org) —Scientists from the Friedrich Miescher Institute for Biomedical Research have discovered how microRNAs repress translation of mRNAs. In a structure-function study published in Molecular Cell, they report different modes of recruitment of the CCR4-NOT complex to mRNAs targeted by microRNAs. ...
Scientists at The Scripps Research Institute (TSRI) have determined the most detailed picture yet of a crucial part of the hepatitis C virus, which the virus uses to infect liver cells.
Konstantinos Floridis's insight:
Most detailed picture ever of key part of hepatitis C This is the new picture of hepatitis C's E2 protein, which the virus uses to infect liver cells, will aid in the design of a vaccine against the disease. Credit: Christina Corbaci, The Scripps Research Institute.
Hawking has given many lectures to the general public. Below are some of the more recent public lectures. Included with these lectures is a Glossary of some of the terms used.
Into a Black Hole (2008): Is it possible to fall in a black hole, and come out in another universe? Can you escape from a black hole once you fall inside? What have we discovered about black holes?
The Origin of the Universe (2005): Why are we here? Where did we come from? The answer generally given was that humans were of comparatively recent origin, because it must have been obvious, even at early times, that the human race was improving in knowledge and technology. So it can't have been around that long, or it would have progressed even more.
Godel and the End of Physics (2002): How far can we go in our search for understanding and knowledge? Will we ever find a complete form of the laws of nature - a set of rules that in principle at least enable us to predict the future to an arbitrary accuracy, knowing the state of the universe at one time? A qualitative understanding of the laws has been the aim of philosophers and scientists, from Aristotle onwards.
Space and Time Warps (1999): In science fiction, space and time warps are a commonplace. They are used for rapid journeys around the galaxy, or for travel through time. But today's science fiction, is often tomorrow's science fact. So what are the chances for space and time warps?
Does God Play Dice (1999): Can predict the future, or is it arbitrary and random? In ancient times, the world must have seemed pretty arbitrary. Disasters such as floods or diseases must have seemed to happen without warning or apparent reason. Primitive people attributed such natural phenomena, to a pantheon of gods and goddesses, who behaved in a capricious and whimsical way. There was no way to predict what they would do, and the only hope was to win favour by gifts or actions.
The Beginning of Time (1996): Has time itself a beginning, and will it have an end? All the evidence seems to indicate, that the universe has not existed forever, but that it had a beginning, about 15 billion years ago. This is probably the most remarkable discovery of modern cosmology. Yet it is now taken for granted. We are not yet certain whether the universe will have an end.
Life in the Universe (1996): Speculations about how life has developed in the universe, and in particular, the development of intelligent life.
Ο Γκίκας Μαγιορκίνης του Τμήματος Ζωολογίας του πανεπιστημίου της Οξφόρδης και ο Ρόμπερτ Μπέλσοου της Σχολής Βιοϊατρικών Επιστημών του πανεπιστημίου του Πλίμουθ, που έκαναν τη σχετική δημοσίευση στο διεθνούς κύρους περι...
European Commission - Press Release details page - Ευρωπαϊκή Επιτροπή Δελτίο Τύπου Βρυξέλλες, 21 Αυγούστου 2013 Την παγκόσμια τάση προς τη δωρεάν διάθεση των αποτελεσμάτων ερευνητικών έργων στους αναγνώστες, τη λεγόμενη «ανοιχτή πρόσβαση»,...
Νέα στοιχεία για την εξασθένηση της λειτουργίας της μνήμης με την πάροδο της ηλικίας ανακάλυψαν αμερικανοί επιστήμονες, σύμφωνα με άρθρο του επιστημονικού εντύπου Science Translational Medicine. Οι ερευνητές του Ιατρικού Κέντρου ...