TOP 100 SCIENCE SITES
| |||
|
| |||
| |||
|
| |||
| Fertility study on mice eggs raise hope for older mothers UK research identifying loss of key protein in mice eggs is seen as a breakthrough that may help prevent birth defectsScientists have made a breakthrough in understanding why older women become less fertile, suffer a miscarriage or have a baby with Down's syndrome.The discovery could ultimately lead to treatments that would increase the chances of a successful pregnancy for growing numbers of would-be mothers in their late 30s and early 40s.Researchers led by Dr Mary Herbert, an expert in reproductive biology at Newcastle University's Institute for Ageing and Health, have identified why some older women produce abnormal eggs, according to findings published in the journal Current Biology.It has been known for a long time that would-be mothers who are nearing the end of their fertility are at higher risk than usual of having eggs that are affected by chromosomal abnormalities, but the underlying cause has been unclear.The new study has identified problems arising from a woman's declining stock of proteins called Cohesins, which act as binding agents to hold chromosomes together by keeping them inside a ring. They are vital to ensure that chromosomes split evenly when cells divide.Women's supplies of Cohesins fall as they age, Herbert and her colleagues discovered. Tests on eggs taken from both young and old mice indicated that the amount of Cohesins in women's bodies declines after their mid-30s.When that happens it means that chromosomes are less tightly held together and they are therefore more likely to result in defective eggs, which can cause problems such as miscarriage and Down's syndrome.Every cell in the human body, apart from eggs and sperm, contains two copies of each of the body's 23 chromosomes. Sperm and eggs must lose one copy each as they prepare for fertilisation. That process involves a complicated form of cell division.This problem is compounded with eggs, because the attachments that hold chromosomes together have to be maintained by Cohesins until the egg divides just before ovulation.When Herbert's team studied chromosomes during division in the egg, they found that the lower levels of Cohesin in eggs in older females led to some chromosomes becoming trapped and unable to divide properly."Reproductive fitness in women declines dramatically from the mid-30s onwards. Our findings point to Cohesin being a major culprit in this", said Herbert. More work was needed to understand why Cohesin declines over women's reproductive years, and such knowledge could lead to ways being developed to stop that loss from occurring.Dr Peter Bowen-Simpkins, the medical director of the London Women's Clinic network of private fertility clinics and spokesman for the Royal College of Obstetricians and Gynaecologists, said the study was "very exciting" and could lead to real improvements in older women's chances of having children."This breakthrough could mean the difference between success and failure – them having a baby or not – for the fast-growing number of women who are trying to conceive after their late 30s," he added.ReproductionBiologyFertility problemsGeneticsDenis Campbellguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
Pipelines and Anxiety: What Next? There may be a lasting political impact from recent accidents, especially because memories of the BP spill in the gulf are still fresh. feeds.nytimes.com |
Stephen Hawking has not yet disproved God's role in creation The existence of the universe cannot be explained by science aloneAccording to your report, Stephen Hawking claims that God is redundant in explaining the origins of the universe, stating that "the big bang, rather than occurring following the intervention of a divine being, was inevitable due to the law of gravity" (Stephen Hawking says universe not created by God, 2 September). The article publishes an extract from Hawking's new book: "Spontaneous creation is the reason there is something rather than nothing, why the universe exists, why we exist ... It is not necessary to invoke God to light the blue touch paper and set the universe alight." It seems Hawking believes that a law of nature (ie the law of gravity), rather than an immaterial deity, explains the existence of the natural order.But what is a law of nature? Some philosophers hold that the laws of nature are grounded in the causal capacities of physical objects: the capacity of water to boil at 100C, and the capacity of salt to dissolve in water (to take two very simple examples). Other philosophers claim that laws of nature are simply brute regularities in the natural world, which have no ultimate explanation. On either conception, it is difficult to see how laws could explain the natural order, as they seem to depend for their own existence upon that natural order.Hawking has never told us what he thinks a law of nature is, and until he does so it is impossible to assess his claim that laws of nature can explain the existence of the natural order in a way that renders traditional arguments for the existence of God unsound.I don't imagine that Hawking is in a hurry to answer this philosophical challenge. The opening page of his book proclaims that "philosophy is dead", due to the fact that philosophers have failed to keep up with mathematical developments in physics. This doesn't stop him, and his co-writer Leonard Mlodinow, indulging in some very crude philosophical discussions of free will and metaphysical realism in later chapters. Hawking is right to say that most philosophers don't understand cutting-edge physics. But it cuts both ways: most physicists don't understand cutting-edge philosophy.The report also claims, as has been much reported in the media, that "Hawking had previously appeared to accept the role of God in the creation of the universe". However, it is not clear that the quotation from his 1988 bestseller, A Brief History of Time, which is produced as evidence of this alleged theological U-turn, was intended by Hawking in anything other than a metaphorical sense. "If we discover a complete theory, it would be the ultimate triumph of human reason – for then we should know the mind of God." Reports of Hawking's dramatic conversion to atheism are somewhat exaggerated.The skills that make one good at physics are not necessarily the skills that make one good at philosophy. What is required in philosophy is a certain capacity for thinking about everyday concepts in abstraction from their everyday context, an ability distinct from the mathematical skill essential for being a good physicist. Hawking is a great physicist. But he has so far shown no signs of being a good philosopher. At any rate, he has certainly not provided us with a good response to the cosmological argument for the existence of God, the argument that begins from the demand for an ultimate cause or explanation of the natural order.Stephen HawkingPhilosophyPhilip Goffguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
Mystery Bird: Sedge wren, Cistothorus platensis This small bird exemplifies the confusion that was created by giving the same common name to a number of unrelated bird speciesSedge wren, known in South America as the Grass Wren, and formerly known as the Short-billed Marsh Wren, Cistothorus platensis, photographed at Anahuac National Wildlife Refuge, Chambers and Galveston counties, Texas, USA. Image: Joseph Kennedy, 9 October 2010 [with binoculars].Nikon D200, Kowa 883 telescope with TSN-PZ camera eyepiece 1/320s f/8.0 at 1000.0mm iso400Question: This cute little North American bird has a common name that has been applied to a variety of unrelated avian taxa. Can you tell me more about this?Response: This is a Sedge wren, known in South America as the Grass Wren, Cistothorus platensis. There are about 80 species of true wrens in approximately 20 genera. Interestingly, only one species of Troglodytes wren occurs in the Old World, where it is known simply as the "wren." This species, which is known as the Winter Wren in North America, is where the name originated. However, the name "wren" has been confusingly applied to a wide variety of unrelated songbird families throughout the world. In Europe, species of Regulus are commonly known as "wrens" -- the Firecrest and Goldcrest are called the "fire-crested wren" and "golden-crested wren", respectively. The name, "wren," has also been given to species in the Australasian family Maluridae, in the New Zealand family Acanthisittidae, and permutations of that name are given to the antwrens (family Thamnophilidae) and the wren-babblers (family Timaliidae).If you have bird images, video or mp3 files that you'd like to share with a large and appreciate audience, feel free to email them to me for consideration.GrrlScientistguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
Why Egyptian replicas are as good as the real thing Manchester's Tutankhamun exhibition is full of fakes, but no less inspiring for that"What can you see?" asked the people behind archaeologist Howard Carter as he peered through a newly dug hole into the tomb chamber of the boy king Tutankhamun in 1922. "Wonderful things!" gasped Carter. And it was true.Up to then it seemed that all the tombs of the pharaohs of Egypt in the Valley of the Kings had been ransacked by graverobbers long ago: archaeologists found mummies, but no gold. Somehow this young ruler's tomb had never been touched. Carter found its treasures piled around the walls inside the secret chamber, perfectly preserved in the sealed vault, just as they looked the day the tomb was closed. Now you can see them, quite as perfect, in Manchester – with one catch.The exhibition Tutankhamun – His Tomb and His Treasures, which opened at the Trafford Centre on Friday, boasts the very room that amazed Carter 88 years ago. Golden beds, chairs, chariots, chests and portraits are heaped as they were when he peeked through that tiny aperture: the death mask of Tutankhamun, one of the most astonishing works of art on earth, is here. The only trouble is, none of it is real. All the marvels are reproductions, modelled with digital technology and expertly crafted to mimic the originals, at a cost of £4.4m.Does it matter? Is this exhibition a con, a delusion, a postmodern joke? Is it not a bit rich to sell tickets to a display that is really no more authentic than a horror film with mummies chasing screaming actors through digitally created pyramids? But to get lofty and highfalutin about it is to forget the history of "Egyptomania", the fascination with ancient Egypt that has long gripped western culture. People have been faking Egyptian artefacts for centuries, and mixing those fakes with real relics, in a way that was not stupid, but rather inspired curiosity, discoveries, learning. In the 17th century, sculptor Gianlorenzo Bernini stuck an ancient obelisk on the back of a stone elephant, mixing real archaeology with his own art. In the age of Napoleon, every fashionable house had a faked-up, Egyptian-style chaise longue. In Regency London you could visit the Egyptian Hall in Piccadilly, a simulated Egyptian temple complete with colossal columns and statues, run as a profitable enterprise (today Harrods has its own Egyptian Hall).The Manchester event is in this tradition. If it inspires, it inspires. You can visit the British Museum's Book of the Dead show next month to see how real Egyptian relics match up to its illusions. Egyptomania thrives on sensation, and museums and diggers have benefited from the popularity of this most amazing of ancient cultures. Egyptologists learned long ago that fakes are fine, so long as they generate enthusiasm for the real thing.MuseumsArchaeologyArtHistory and history of artMuseumsManchesterJonathan Jonesguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |