|Three Neptunes! |
Humans & Chimps Get Closer!
Himalayan Forests, UK Dolphins,
Life Before the Big Bang?
|Three Neptunes! |
European Southern Observatory News Release
Artist's impression of the Planetary System Around HD 69830. The HARPS measurement
reveal the presence of three planets with masses between 10 and 18 Earth masses around
HD 69830, a rather normal star slightly less massive than the Sun. The planets' mean
distance are 0.08, 0.19, and 0.63 the mean distance between the Earth and the Sun. From
previous observations, it seems that there exists also an asteroid belt, whose location is
unknown. It could either lie between the two outermost planets, or farther from its parent
star than 0.8 the mean Earth-Sun distance. (ESO)
May 18, 2006 - Using the ultra-precise HARPS spectrograph on ESO's 3.6-m telescope at La Silla (Chile), a team of European astronomers have discovered that a nearby star is host to three Neptune-mass planets. The innermost planet is most probably rocky, while the outermost is the first known Neptune-mass planet to reside in the habitable zone. This unique system is likely further enriched by an asteroid belt.
"For the first time, we have discovered a planetary system composed of several Neptune-mass planets", said Christophe Lovis, from the Geneva Observatory and lead-author of the paper presenting the results.
During more than two years, the astronomers carefully studied HD 69830, a rather inconspicuous nearby star slightly less massive than the Sun. Located 41 light-years away towards the constellation of Puppis (the Stern), it is, with a visual magnitude of 5.95, just visible with the unaided eye.
The astronomers' precise radial-velocity measurements allowed them to discover the presence of three tiny companions orbiting their parent star in 8.67, 31.6 and 197 days.
"Only ESO's HARPS instrument installed at the La Silla Observatory, Chile, made it possible to uncover these planets", said Michel Mayor, also from Geneva Observatory, and HARPS Principal Investigator. "Without any doubt, it is presently the world's most precise planet-hunting machine."
The detected velocity variations are between 2 and 3 metres per second, corresponding to about 9 km/h! That's the speed of a person walking briskly. Such tiny signals could not have been distinguished from 'simple noise' by most of today's available spectrographs.
The newly found planets have minimum masses between 10 and 18 times the mass of the Earth. Extensive theoretical simulations favour an essentially rocky composition for the inner planet, and a rocky/gas structure for the middle one. The outer planet has probably accreted some ice during its formation, and is likely to be made of a rocky/icy core surrounded by a quite massive envelope. Further calculations have also shown that the system is in a dynamically stable configuration.
The outer planet also appears to be located near the inner edge of the habitable zone, where liquid water can exist at the surface of rocky/icy bodies. Although this planet is probably not Earth-like due to its heavy mass, its discovery opens the way to exciting perspectives.
"This alone makes this system already exceptional", said Willy Benz, from Bern University, and co-author. "But the recent discovery by the Spitzer Space Telescope that the star most likely hosts an asteroid belt is adding the cherry to the cake."
With three roughly equal-mass planets, one being in the habitable zone, and an asteroid belt, this planetary system shares many properties with our own solar system.
"The planetary system around HD 69830 clearly represents a Rosetta stone in our understanding of how planets form", said Michel Mayor. "No doubt it will help us better understand the huge diversity we have observed since the first extra-solar planet was found 11 years ago."
High resolution images and their captions are available - http://www.eso.org/outreach/press-rel/pr-2006/phot-18-06.html
Video footage and animations are also available - http://www.eso.org/outreach/press-rel/pr-2006/vid-18-06.html
European Southern Observatory - http://www.eso.org
|Humans and Chimps Get Closer! |
More like kissing cousins than ever...
Broad Institute of MIT and Harvard News Release
May 17, 2006 - The evolutionary split between human and chimpanzee is much more recent -- and more complicated -- than previously thought, according to a new study by scientists at the Broad Institute of MIT and Harvard and at Harvard Medical School published in the May 17 online edition of Nature.
The results show that the two species split no more than 6.3 million years ago and probably less than 5.4 million years ago. Moreover, the speciation process was unusual -- possibly involving an initial split followed by later hybridization before a final separation.
"The study gave unexpected results about how we separated from our closest relatives, the chimpanzees. We found that the population structure that existed around the time of human-chimpanzee speciation was unlike any modern ape population. Something very unusual happened at the time of speciation", said David Reich, the senior author of the Nature paper, and an associate member of the Broad Institute and assistant professor at Harvard Medical School's Department of Genetics.
Previous molecular genetic studies have focused on the average genetic difference between human and chimpanzee. By contrast, the new study exploits the information in the complete genome sequence to reveal the variation in evolutionary history across the human genome. In theory, scientists have long known that some genomic regions must be 'older' than others, meaning that they trace back to different times in the common ancestral population that gave rise to both humans and chimps. But, the new study is the first to actually measure the range of ages.
It gave three surprising results:
- the time of from the beginning to the completion of divergence between the two species ranges over more than 4 million years across different parts of the genome. This range is much larger than expected.
- the youngest regions are unexpectedly recent -- being no more than 6.3 million years old and probably no more than 5.4 million years old. This finding implies that human-chimp speciation itself is far more recent than previously thought.
- if one looks only at the X chromosome, it almost entirely falls at the lower end of the time frame. In fact, the average age of the X chromosome is ~1.2 million years "younger" than the average across the 22 autosomal (non-sex) chromosomes.
"The genome analysis revealed big surprises, with major implications for human evolution," said Eric Lander, Director of the Broad Institute and co-author of the Nature paper. "First, human-chimp speciation occurred more recently than previous estimates. Second, the speciation itself occurred in an unusual manner that left a striking impact across chromosome X. The young age of chromosome X is an evolutionary 'smoking gun.'"
The new study raises questions about
the evolutionary interpretations that
stem from this famous "Toumaï" fossil.
The estimate that humans and chimpanzees probably split less than 5.4 million years ago is more recent by ~1 to 2 million years than a previous estimate of 6.5-7.4 million years based on the famous Toumaï hominid fossil (Sahelanthropus tchadensis), which has features thought to be distinctive to the human lineage.
"It is possible that the Toumaï fossil is more recent than previously thought," said Nick Patterson, a senior research scientist and statistician at the Broad Institute and first author of the Nature paper.
"But if the dating is correct, the Toumaï fossil would precede the human-chimp split. The fact that it has human-like features suggest that human-chimp speciation may have occurred over a long period with episodes of hybridization between the emerging species."
The possibility of "hybridization" -- that is, initial separation of the two species, followed by interbreeding and then final separation -- would also explain the strange phenomenon seen on chromosome X.
Interbreeding is known to place strong selective pressures on sex chromosomes, which could translate to a very young age for chromosome X.
"Hybridization" is commonly observed to play a role in speciation in plants, but evolutionary biologists do not generally view it as an important way to produce a new species in animals.
"A hybridization event between human and chimpanzee ancestors could help explain both the wide range of divergence times seen across our genomes, as well as the relatively similar X chromosomes," said Reich. "That such evolutionary events have not been seen more often in animal species may simply be due to the fact that we have not been looking for them."
As the researchers note in the Nature paper, it should be possible to refine the timeline of speciation and test the possible explanations based on complete genome sequencing of gorilla and other primates, which is already underway at several centers including the Broad Institute.
Broad Institute of MIT and Harvard - http://www.broad.mit.edu
|Bush Repeats Woodrow Wilson's Mistakes |
|Blackwell Publishing News Release |
May 17, 2006 - An article published in the latest issue of Diplomatic History examines the historical similarities between how George W. Bush and Woodrow Wilson conducted foreign policy.
In Bush's global war on terrorism, he neglected to coordinate the ends and means of U.S. foreign policy. Like President Woodrow Wilson during World War I, Bush proclaimed historic American ideals as his goals. The Bush Doctrine appealed to Americans by affirming American ideals, but its success abroad depended on its relevancy to foreign affairs.
The Bush Doctrine reaffirmed Wilson's ideological legacy: viewing the United States as an exceptional nation with a providential mission to transform world history. Because of this, Bush repeated the same mistake that Wilson had made over 80 years ago.
"Wilson's earlier failure suggests that Bush's war for perpetual peace is more likely to result in unanticipated costs and unintended consequences," states the author, Lloyd E. Ambrosius.
Bush failed to recognize that the United States, even with its preeminent global power, could not force other nations to embrace the values and institutions he expected to impose on them.
This disparity between ends and means became increasingly apparent after 9/11. Yet, just as Wilson had pursued his vision of the League of Nations after World War I, despite the failure of his diplomacy in postwar Europe and the collapse of his presidency in the United States, Bush has persisted in his unrealistic quest for a new world order.
"With the United States entangled in ongoing wars, the issues in this public debate are vital to the nation's and the world's future," states Lloyd E. Ambrosius. "They are not just academic."
This article is published in the June issue of Diplomatic History. As the sole journal devoted to the history of U.S. diplomacy, foreign relations, and national security, Diplomatic History examines issues from the colonial period to the present in a global and comparative context. It is published on behalf of The Society for Historians of American Foreign Relations.
Blackwell Publishing - http://www.blackwellpublishing.com
|Disappearing Himalayan Forests |
New Scientist News Release
By Emma Young
May 17, 2006 - The Himalayas may never be the same again. The forests growing on the roof of the world are disappearing, and the rate of deforestation is so rapid that a quarter of animal and plant species native to this biodiversity hotspot, including tigers and leopards, could be gone by the end of the century.
Worse, the Indian government is oblivious to the problem because official figures erroneously suggest that forest cover will rise rather than fall. This mistake has led to the approval of new schemes, such as hydroelectric dams, that will exacerbate the devastation.
The Himalayan region has long been recognised as extremely rich in animal and especially plant diversity. For instance, a paper published last year in Science (vol 308, p 405) concluded that Himalayan watersheds harbour more diverse ecosystems than the Amazon. "Himalaya's importance as a biodiversity-rich area and its need for conservation cannot be overemphasised," says Maharaj Pandit of the University of Delhi, India.
Now a team of researchers led by Pandit have revealed evidence of widespread deforestation in the Indian Himalaya region, which threatens tigers, black bears, musk deer, leopards, golden eagles and bearded vultures that depend on the forests. Large-scale conservation efforts are urgently needed to avoid the disappearance of these animals from the region, they say.
Pandit's team analysed high resolution satellite images of the region dating from 1972-1974, 1980-1983 and 1999-2001. The team also went out into the field to verify ground features that could not easily be identified in the images. They classed regions with more than 40 per cent forest cover as dense forests, and those with between 10 and 40 per cent of cover as open forests. By 2000, the region had lost 15 per cent of its forest cover compared with the early 1970s. By 2100, it will have lost almost half its forests, the team predicts.
Less than one-third of the dense forest on which many native species depend will survive in the western Himalaya, while less than three-quarters in the eastern Himalaya will remain (Biodiversity & Conservation, DOI: 10.1007/s10531-006-9038-5).
What's more, the researchers consider these conservative estimates, as they think increases in population and agriculture will increase the deforestation rate.
However, official Indian government statistics from the ministry of agriculture and the Forest Survey of India imply that total forest cover across the Indian Himalaya will expand by more than 40 per cent between 1970 and 2100. The researchers suspect the discrepancy between the official figures and their satellite data may stem from poor sampling, a lack of technical expertise and a lack of resources in the government institutes.
The government might also attach too much weight to projects aimed at stopping commercial logging and at replanting trees in more remote regions, while the more serious threat is deforestation by villagers, they suggest.
These "miscalculations" in land-use decisions could have severe repercussions. "More than 80 per cent of proposed hydro-projects in India are located in the Himalaya," says Pandit. "Diversion of forest lands for hydro-irrigation projects is second only to agriculture in India."
This article appears in New Scientist Magazine Issue: 20 May 2006
New Scientist - http://www.newscientist.com
|Wal-Mart Increases Poverty |
|Blackwell Publishing News Release |
May 17, 2006 - A study published in the latest issue of Social Science Quarterly is the first to examine the effect of Wal-Mart stores on poverty rates. The study found that nationwide an estimated 20,000 families have fallen below the official poverty line as a result of the chain's expansion.
During the last decade, dependence on the food stamp program nationwide increased by 8 percent while in counties with Wal-Mart stores, the increase was almost twice as large at15.3 percent.
"After controlling for other factors determining changes in the poverty rate over time, we find that both counties with more initial Wal-Mart stores and with more additions of stores between 1987 and 1998 experienced greater increases (or smaller decreases) in family poverty rates during the 1990's economic boom period," Stephan Goetz a Professor of Agricultural and Regional Economics at The Pennsylvania State University states.
Although Wal-Mart employs many people living in its communities, for most, the hours worked and the wages paid do not help these families transition out of poverty.
Another effect is that the closing of "mom and pop" stores following the appearance of a store leads to the closing of local businesses that previously supplied those stores including: wholesalers, transporters, logistics providers, accountants, lawyers and others.
The authors state that "by displacing the local class of entrepreneurs, the Wal-Mart chain also destroys local leadership capacity." They encourage community leaders to think about programs and policies in anticipation of helping those displaced by the arrival of the chain.
Blackwell Publishing Ltd. - http://www.blackwellpublishing.com
|UK Dolphins At Risk! |
Blackwell Publishing News Release
May 17, 2006 - Pile driving and industrial noise may adversely affect dolphin behaviour, communication and breeding, according to a scientific paper in CIWEM’s Water and Environment Journal.
Bottlenose dolphins that reside in designated Special Areas of Conservation throughout the UK, including Dorset, Anglesey and Cornwall, might be at risk from pile driving. The frequency range of pile driving noise could interfere with their ability to communicate, find food and avoid predators. This has the potential to affect their behaviour, health and their ability to breed successfully. Lactating females and young calves might be particularly vulnerable
Recently more than 600 dolphins died mysteriously off the Indian Ocean archipelago in Zanzibar. The phenomenon has created a stir among marine experts, with varying theories that the Indian Ocean Bottlenose dolphins may have been hurt by pollution or underwater noise.
Author, Dr. Jonathan David, MCIWEM, suggests that mitigation measures be put in place to help prevent any adverse impacts upon dolphin populations. Operations should be restricted to low tide and suspended during calving season, an exclusion zone should be monitored before any activity starts and marine work should cease if a dolphin enters the work area. Other innovative ideas include creating an air bubble curtain and creating a ramped warning signal to give dolphins time to leave the area before work commences.
Dr. David also calls for further research into the reactions of marine mammals to industrial noise to help mitigate future effects in relation to the increase in off-shore industry, such as the construction of wind farms.
Blackwell - http://www.blackwellpublishing.com
|Life Before The Big Bang? |
Big Bang Timeline (NASA)
Penn State News Release
May 12, 2006 - According to Einstein’s general theory of relativity, the Big Bang represents The Beginning, the grand event at which not only matter but space-time itself was born.
While classical theories offer no clues about existence before that moment, a research team at Penn State has used quantum gravitational calculations to find threads that lead to an earlier time.
“General relativity can be used to describe the universe back to a point at which matter becomes so dense that its equations don’t hold up,” says Abhay Ashtekar, Holder of the Eberly Family Chair in Physics and Director of the Institute for Gravitational Physics and Geometry at Penn State.
“Beyond that point, we needed to apply quantum tools that were not available to Einstein.”
By combining quantum physics with general relativity, Ashtekar and two of his post-doctoral researchers, Tomasz Pawlowski and Parmpreet Singh, were able to develop a model that traces through the Big Bang to a shrinking universe that exhibits physics similar to ours.
In research reported in the current issue of Physical Review Letters, the team shows that, prior to the Big Bang, there was a contracting universe with space-time geometry that otherwise is similar to that of our current expanding universe. As gravitational forces pulled this previous universe inward, it reached a point at which the quantum properties of space-time cause gravity to become repulsive, rather than attractive.
The figure represents our expanding universe as the right branch
of the arc. Our time now is located at the 1.8 grid mark on the right
side of the drawing. According to Ashtekar's team's calculations,
when looking backward throughout the history of the universe, 'time'
does not go to the point of the Big Bang but bounces to the left branch
of the drawing, which describes a contracting universe. Singh explains,
"The state of the universe depicted by its wavefunction is shown in space
(\mu) and time(\phi). The big bang singularity lies where space
vanishes (goes to zero). Our expanding phase of the universe is shown by
the right branch which, when reversed backward in time, bounces near
the Big Bang to a contracting phase (left branch) and never reaches the
Big Bang." (ECS)
“Using quantum modifications of Einstein’s cosmological equations, we have shown that in place of a classical Big Bang there is in fact a quantum Bounce,” says Ashtekar. “We were so surprised by the finding that there is another classical, pre-Big Bang universe that we repeated the simulations with different parameter values over several months, but we found that the Big Bounce scenario is robust.”
While the general idea of another universe existing prior to the Big Bang has been proposed before, this is the first mathematical description that systematically establishes its existence and deduces properties of space-time geometry in that universe.
The research team used loop quantum gravity, a leading approach to the problem of the unification of general relativity with quantum physics, which also was pioneered at the Penn State Institute of Gravitational Physics and Geometry.
In this theory, space-time geometry itself has a discrete 'atomic' structure and the familiar continuum is only an approximation. The fabric of space is literally woven by one-dimensional quantum threads.
Near the Big-Bang, this fabric is violently torn and the quantum nature of geometry becomes important. It makes gravity strongly repulsive, giving rise to the Big Bounce.
"Our initial work assumes a homogenous model of our universe," says Ashtekar. "However, it has given us confidence in the underlying ideas of loop quantum gravity. We will continue to refine the model to better portray the universe as we know it and to better understand the features of quantum gravity."
The research was sponsored by the National Science Foundation, the Alexander von Humboldt Foundation, and the Penn State Eberly College of Science.
Penn State - http://www.science.psu.edu