What makes a man a man? Socially, that is a complicated question. Genetically, however, it is as simple as a single Y chromosome.
But guys, that chromosome is in trouble.
In a new study, researchers say there is a dramatic loss of genes from the human Y chromosome that eventually could lead to its complete disappearance -- in the next few millennia. While the Y chromosome's degeneration has been known to geneticists and evolutionary biologists for decades, the study sheds new light on some of the evolutionary processes that may have contributed to its demise and posits that, as the degeneration continues, the Y chromosome could disappear from our genetic repertoire entirely.
Science & Technology
© Olivier Staiger
"The high skyscraper with the hole is the Shanghai World Financial Center, the other one is the Jin Mao building," says Staiger. "The sun halo was caused by a hazy layer of icy clouds hanging over the city."
Shanghai is the largest city in China with a population greater than 20 million. On Wednesday, the Moon's shadow will linger over the great metropolis for nearly six full minutes, giving residents a stunning and lengthy view of the Sun's ghostly corona. In addition to Shanghai, the path of totality crosses a number of other large cities in India and China--e.g., Surat, Vadodara, Bhopal, Varanasi, Chengdu, Chongqing, Wuhan, Hefei, Hangzhou--each with populations numbering in the millions. This could be the best-observed solar eclipse in human history.
© Anthony Wesley
"The jet-black mark is near Jupiter's south pole (south is up in the image)," says Wesley. "I have imagery of that same location from two nights earlier without the impact mark, so this is a very recent event. The material has already begun to spread out in a fan shape on one side, and should be rapidly pulled apart by the fast jetstream winds. I recorded a lot of footage, and will be generating more images and a rotation animation soon."
© Abigail Allwood
Rare, paleosurface view of how conical stromatolites would appear if one snorkeled in the shallows of a reef.
Rare, paleosurface view of how conical stromatolites would appear if one snorkeled in the shallows of a reef.
Abigail Allwood, who studies planetary habitability at NASA's Jet Propulsion Laboratory, led the research. She and her colleagues studied stromatolites, which are dome- or column-like sedimentary rock structures formed in shallow water, layer by layer, over long periods of geologic time.
Geologists have long known that the large majority of the relatively young stromatolites they study - those half a billion years old or so - have a biological origin; they're formed with the help of layers of microbes that grow in a thin film on the seafloor.
© Unknown
Geophysicists from the Chinese Academy of Sciences are preparing an unprecedented array of highly sensitive instruments at six sites across the country to take gravity readings during the total eclipse due to pass over southern China on 22 July. The results, which will be analysed in the coming months, could confirm once and for all that anomalous fluctuations observed during past eclipses are real.
"It sounds like what is really necessary to break the uncertainty," says Chris Duif of Delft University of Technology in The Netherlands. "I'm not really convinced the anomaly exists, but it would be revolutionary if it turned out to be true," he says.
Bkis, as a member of APCERT, received a request from KrCERT (Korean Computer Emergency Response Team) to investigate the incident that was performing DDoS attacks on websites of South Korea and the US.
We have analyzed the malware pattern that we received from KrCERT and have located the botnet controlled by 8 Command and Control (C&C) servers via controlling code embedded in a file named "flash.gif". Every 3 minutes, zombies randomly select one of the 8 servers to connect to and to receive orders. Especially, we found a master server located in UK which controls all of the 8 C&C servers to make a series of cyber-attack last week. So the source of the attacks has been identified to be in UK. The existence of master server has never been reported before.
We have analyzed the malware pattern that we received from KrCERT and have located the botnet controlled by 8 Command and Control (C&C) servers via controlling code embedded in a file named "flash.gif". Every 3 minutes, zombies randomly select one of the 8 servers to connect to and to receive orders. Especially, we found a master server located in UK which controls all of the 8 C&C servers to make a series of cyber-attack last week. So the source of the attacks has been identified to be in UK. The existence of master server has never been reported before.
Rob Simcoe seems slightly nervous as he fishes a balloon from a canister of liquid nitrogen. "I haven't done this demonstration before," the astronomer admits, moving the balloon over to a nearby candle flame. The balloon is actually a galaxy. Heated by the candle, it should expand and pop, just as we think galaxies in the early universe produced violent outflows of hot gas when warmed by exploding stars.
© NASA/JPL-Caltech
A Martian menace.
A Martian menace.
Martian dust is particularly clingy. This was noticed more than a decade ago when surprisingly large amounts stuck to the wheels of NASA's Sojourner rover. Static electricity was thought to be to blame, but no one could explain how the particles became charged. Now a team led by Keith Forward of Case Western Reserve University in Cleveland, Ohio, have an answer.
The team suspected that electrons could jump back and forth between dust grains as they collide in the wind. Smaller grains would be more likely to retain their extra electrons, giving them a negative charge, while larger grains would be left positively charged. Sure enough, they managed to electrically charge grains of Hawaiian volcanic ash, chosen for its similarity to Martian dust, by blowing them around in a container (Geophysical Research Letters, DOI: link).
© NASA/GSFC/ASU
The lunar module Eagle, which was used to carry Apollo 11 astronauts Neil Armstrong and Buzz Aldrin down to the lunar surface on 20 July 1969 is the small bright dot near the centre of this image; its shadow can be seen stretching to its right.
The lunar module Eagle, which was used to carry Apollo 11 astronauts Neil Armstrong and Buzz Aldrin down to the lunar surface on 20 July 1969 is the small bright dot near the centre of this image; its shadow can be seen stretching to its right.
The images were taken by NASA's Lunar Reconnaissance Orbiter (LRO) less than a month after it launched. "I believe this is the first time Apollo hardware has been imaged by anyone in the post-Apollo era," Richard Vondrak, LRO project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland, told reporters on Friday.
"This is only a first glimpse. These are just the first of many images to be coming ... from now they're only going to be getting better," says Michael Wargo, chief lunar scientist at NASA headquarters in Washington, DC.
See a gallery of the images
© Philippe Halsman
Salvador Dali's mental disorders were also the key to his creativity.
Salvador Dali's mental disorders were also the key to his creativity.
The finding could help to explain why mutations that increase a person's risk of developing mental illnesses such as schizophrenia and bipolar syndrome have been preserved, even preferred, during human evolution, says Szabolcs Kéri, a researcher at Semmelweis University in Budapest, Hungary, who carried out the study.
Kéri examined a gene involved in brain development called neuregulin 1, which previous studies have linked to a slightly increased risk of schizophrenia. Moreover, a single DNA letter mutation that affects how much of the neuregulin 1 protein is made in the brain has been linked to psychosis, poor memory and sensitivity to criticism.
About 50 per cent of healthy Europeans have one copy of this mutation, while 15 per cent possess two copies.
