|Bubbling Darkness! |
Bursting Stars! Killer Paint!
Atmospheric Aerosols! 2025!
High Altitude Broadband?
July 19, 2006 - Bubbles of dark matter could be masquerading as supermassive black holes at the centres of galaxies. If so, they could explain the puzzling pattern of X-ray emissions from the heart of the Milky Way.
Cosmologists know that most galaxies host a compact, supermassive object at their centre and they believe these must be black holes. Such a black hole is thought to be responsible for the X-ray flares coming from the middle of our galaxy, which would be caused by the black hole devouring surrounding matter.
But recent observations show that these flares fire roughly every 20 minutes – a regularity that is hard to explain in terms of the behaviour of a black hole.
Axions have very little mass and no electric charge, and they barely interact with other particles. They were originally proposed to fix a problem with the strong force in particle physics, but have more recently been considered as possible candidates for dark matter, the unseen stuff thought to make up nearly 90 per cent of a galaxy's mass.
The model predicts that stable axion bubbles would weigh between about 1 million and 2.5 billion times the mass of the sun – exactly the mass range observed for compact objects at the centres of galaxies.
"There are various studies in progress around the world which suggest that Einstein did not speak the last word on gravity," says Zioutas. For example, extra dimensions can change the way that gravity behaves in extreme cases.
Dark matter axions, however, could be releasing these X-rays as they decay, he says.
July 19, 2006 - A team of astronomers from the UK and Germany have found that a nuclear explosion on the surface of a star 5,000 light years from Earth resulted in a blast wave moving at over 1,700 km per second. Dr. Richard Porcas from the Max Planck Institute for Radio Astronomy in Bonn coordinated the observations with the European VLBI network (EVN). The discovery, reported in the 20th July issue of Nature, was made by bringing together many of the world's radio telescopes into arrays capable of seeing the aftermath of the explosion in incredible detail.
During the night of 12th February this year Japanese astronomers reported that a star called RS Ophiuchi had suddenly brightened and become clearly visible in the night sky. Although this was the latest in a series of such outbursts that have been spotted over the last hundred years or so, it was the first since 1985 and therefore an opportunity to bring to bear new, more powerful, telescopes in an effort to understand the causes and consequences of these eruptions.
Dr Tim O'Brien of The University of Manchester's Jodrell Bank Observatory requested urgent observations with the VLBA (the Very Long Baseline Array of radio telescopes extending from Hawaii to the Caribbean). "Our first observations, made only two weeks after the explosion was reported, showed an expanding blast wave already comparable in size to Saturn's orbit around the Sun.
However, we needed to use the world's most powerful radio telescopes because, from a distance of 5,000 light years, its apparent size on the sky was only 5 millionths of a degree - the size of a football seen from 2,700 km away."
Eventually enough gas collects on the white dwarf for thermonuclear reactions to begin, similar to those which power the Sun but which runaway into a massive explosion. In less than a day, its energy output increases to over 100,000 times that of the Sun, and the gas (about the mass of the Earth) is thrown into space at speeds of several thousand km per second. This ejected matter then slams into the extended atmosphere of the bloated red giant and sets up blast waves that accelerate electrons to almost the speed of light. The electrons release radio waves as they move through a magnetic field that are then picked up by the telescope arrays.
Over the following months, the team continued to track the outburst using the European VLBI Network (EVN) which includes telescopes in South Africa and China, the MERLIN array of radio telescopes in the UK, and the Very Long Baseline Array (VLBA) and Very Large Array (VLA) in the USA, a truly global effort.
Over the next few months our observations have shown it turning from a ring into a cigar-like shape. It's going to need a lot more work to understand exactly what causes this but either the explosion shoots jets of matter in opposite directions or somehow the atmosphere of the red giant is shaping the ejected material."
|Kent State University News Release |
July 18, 2006 - Oppressive summertime heat claims more lives than all other weather-related disasters combined, including tornadoes and hurricanes. During 2003, a heat wave across Europe killed as many as 40,000 people.
“Heat is a stealth killer,” says Dr. Scott Sheridan, Kent State associate professor in geography. Funded by the Environmental Protection Agency, Sheridan recently finished conducting a study on how effectively heat warning systems have been implemented in four cities for which he developed heat warning systems, including Dayton, Ohio, Philadelphia, Phoenix, and Toronto, Ontario.
Sheridan surveyed residents 65 and older in each of the four regions about their perception of heat vulnerability, their knowledge of options for dealing with the weather, and why they did or did not take action to avoid negative health outcomes during the heat emergency.
He found that almost 90 percent were aware a heat warning was issued, but only about half of the people did anything about it. Many thought messages were targeting the elderly and did not view themselves as part of that group. For those who did change their behavior on hot days, it was not necessarily due to heat warnings issued by weather forecasters but instead based on their own perceptions of heat.
Kent State University - http://imagine.kent.edu/media
CINCINNATI July 17, 2006 - Environmental and occupational health experts at the University of Cincinnati (UC) have found that major countries—including India, China and Malaysia—still produce and sell consumer paints with dangerously high lead levels.
The report appears in the early online edition of the journal Environmental Research, to be published in September 2006.
The researchers say that this lead-based paint production poses a global health threat, and a worldwide ban is urgently needed to avoid future public health problems.
Lead is a malleable metal previously used to improve the durability and color luster of paint used in homes and other buildings and on steel structures, such as bridges. Now scientifically linked to impaired intellectual and physical growth in children, lead is also found in some commonly imported consumer products, including candy, folk and traditional medications, ceramic dinnerware and metallic toys and trinkets.
In a two-year study headed by Scott Clark, PhD, the UC-led research team found that more than 75 percent of the consumer paint tested from countries without controls—including India, Malaysia and China—had levels exceeding U.S. regulations. Collectively, the countries represent more than 2.5 billion people. In Singapore, which enforces the same lead restriction on new paint as the United States, lead levels were significantly lower.
“Paint manufacturers are aggressively marketing lead-based paints in countries without lead content restrictions,” says Clark, professor of environmental health at UC. “In some cases, companies are offering the same or similar products, minus the lead, in a regulated country.”
“There is a clear discrepancy in product safety outside the United States,” he adds, “and in today’s global economy, it would be irresponsible for us to ignore the public health threat for the citizens in the offending countries—as well as the countries they do business with.”
This study, Dr. Clark says, is believed to be the first to show that new paint in many unregulated Asian countries greatly exceeds U.S. safety levels.
The UC-led team analyzed 80 consumer paint samples of various colors and brands from four countries—India, Malaysia, China and Singapore—to determine the amount of lead and compare them with U.S. standards.
Each paint sample was applied in a single layer to a wood block, left to dry and then removed and analyzed in UC laboratories for lead content.
Although American brand paints were not available for purchase in this study, several U.S. multinational paint companies are among the top in Asia and some Asian paint companies have arrangements with U.S. companies.
July 17, 2006 - Scientists at The University of Manchester have created a virtual computer world designed to test telepathic ability.
The system, which immerses an individual in what looks like a life-size computer game, has been created as part of a joint project between The University's School of Computer Science and School of Psychological Sciences.
Approximately 100 participants will take part in the experiment which aims to test whether telepathy exists between individuals using the system.
The project will also look at how telepathic abilities may vary depending on the relationships which exist between participants.
|Atmospheric Aerosols and Climate Change|
Rehovot Israel July 17, 2006 – A scientist at the Weizmann Institute of Science and his colleagues caused a storm in the atmospheric community when they suggested a few years back that tiny airborne particles, known as aerosols, may be one of the main culprits causing climate change – having, on a local scale, an even greater impact than the greenhouse gases effect. Attempts to understand how these particles influence clouds have generated many uncertainties.
A new paper by Dr. Ilan Koren of the Weizmann Institute Environmental Studies and Energy Research Department and Dr. Yoram Kauffman of the NASA/Goddard Space Flight Center, USA,* published in Science Express online, weaves together two opposing effects of atmospheric aerosols to provide a comprehensive picture of how they may be affecting our climate.
Cloud formation is dependent upon the presence of small amounts of aerosols such as sea salt and desert dust. These tiny particles serve as the seeds around which water vapor in the air condenses, forming tiny water droplets that rise as they release heat. As the small droplets rise, they collide and merge with larger droplets. When the droplets reach a critical size, gravity takes over, causing them to fall from the cloud in the form of rain.
One of the controversies surrounding the extent of aerosol impact on climate change is the duality of their influence. On the one hand, Koren and his colleagues previously found evidence to suggest that the extra seeds planted in the atmosphere by the emission of man-made aerosols (pollution, forest fires, and fuel combustion) lead to more, but smaller-sized, water droplets.
The formation of larger water droplets by the collision process is less efficient and, therefore, rainfall is suppressed. The smaller droplets are lifted higher up into the atmosphere, creating larger and taller clouds that will persist longer. Not only does this alter the whole water cycle, but the increased cloud cover reflects more of the sun's radiation back into space, creating a local cooling effect on Earth.
But to complicate matters, Koren, in another study, showed that certain types of aerosols – those containing black carbon – can also decrease cloud cover, ultimately leading to a warming effect. This occurs as black carbon absorbs part of the sun's radiation, warming the surrounding atmosphere and reducing the difference in temperature between the Earth's surface and the upper atmosphere.
This combination prevents atmospheric instability – the condition needed to form clouds and rain. A stable atmosphere means fewer clouds; fewer clouds mean less reflection of sunlight; less reflection of sunlight and absorption of radiation lead to warming.
|2025 - Where Will You Be?|
|Earth Institute at Columbia University News Release |
July 18, 2006 - Researchers at the Center for Climate Systems Research (CCSR), a part of The Earth Institute, have developed a high-resolution map of projected population change for the year 2025.
The innovative map shows a world with large areas of population loss in parts of Eastern Europe and Asia, but significant gains elsewhere. Click for full map (780KB) -
The work, Mapping the Future, is the result of collaboration between CCSR, Hunter College and Population Action International (PAI) and was released this spring in conjunction with an update of PAI’s Web feature, People in the Balance, investigating the relationship between human population and critical natural resources.
The map indicates that the greatest increases in population density through 2025 are likely to occur in areas of developing countries that are already quite densely populated.
In addition, the number of people living within 60 miles of a coastline is expected to increase by 35 percent over 1995 population levels, exposing 2.75 billion people worldwide to the effects of sea level rise and other coastal threats posed by global warming.
Surprisingly, the map further suggests small areas of projected population decline for many regions in which they might be least expected: sub-Saharan Africa, Central and South America, the Philippines, Nepal, Turkey, Cambodia, Burma and Indonesia — areas that have to date been experiencing rapid-to-modest national population growth.
July 19, 2006 - The ability to spot venomous snakes may have played a major role in the evolution of monkeys, apes and humans, according to a new hypothesis by Lynne Isbell, professor of anthropology at UC Davis. The work is published in the July issue of the Journal of Human Evolution.
Primates have good vision, enlarged brains, and grasping hands and feet, and use their vision to guide reaching and grasping. Scientists have thought that these characteristics evolved together as early primates used their hands and eyes to grab insects and other small prey, or to handle and examine fruit and other foods.
Isbell suggests instead that primates developed good close-up eyesight to avoid a dangerous predator -- the snake.
"A snake is the only predator you really need to see close up. If it's a long way away it's not dangerous," Isbell said.
Neurological studies by others show that the structure of the brain's visual system does not actually fit with the idea that vision evolved along with reaching and grasping, Isbell said. But the visual system does seem to be well connected to the "fear module," brain structures involved in vigilance, fear and learning.
Fossils and DNA evidence show that snakes were likely the first serious predators of modern mammals, which evolved about 100 million years ago. Fossils of snakes with mouths big enough to eat those mammals appear at about the same time. Other animals that could have eaten our ancestors, such as big cats, and hawks and eagles, evolved much later.
Venomous snakes evolved about 60 million years ago, raising the stakes and forcing primates to get better at detecting them.
"There's an evolutionary arms race between the predators and prey. Primates get better at spotting and avoiding snakes, so the snakes get better at concealment, or more venomous, and the primates respond," Isbell said.
Some primate groups less threatened by snakes show fewer signs of evolutionary pressure to evolve better vision. For example, the lemurs of Madagascar do not have any venomous snakes in their environment, and in evolutionary terms "have stayed where they are," Isbell said. In South America, monkeys arrived millions of years before venomous snakes, and show less specialization in their visual system compared with Old World monkeys and apes, which all have good vision, including color.
Having evolved for one purpose, a good eye for color, detail and movement later became useful for other purposes, such as social interactions in groups.
Isbell is currently working on a book about primate origins, including her snake hypothesis.
University of California - Davis - http://www.ucdavis.edu
|High Altitude Broadband?|
July 17, 2006 - A three-year project led by the University of York, which aims to revolutionise broadband communications, reaches its climax later this year.
The CAPANINA project, which uses balloons, airships or unmanned solar-powered planes as high-altitude platforms (HAPs) to relay wireless and optical communications, is due to finish its main research at the end of October.
The consortium behind the project will open York HAP Week, a conference from 23 to 27 October, which will showcase the applications of HAPs, as a springboard for future development in this new high-tech sector.
The CAPANINA Final Exhibition will open the conference by highlighting the achievements of the project, which received funding from the EU under its Broadband-for-All, FP6 programme.
The consortium, drawn from Europe and Japan, has demonstrated how the system could bring low-cost broadband connections to remote areas and even to high-speed trains. It promises data rates 2,000 times faster than via a traditional modem and 100 times faster than today's 'wired' ADSL broadband.
CAPANINA's Principal Scientific Officer Dr David Grace said: "The potential of the system is huge, with possible applications ranging from communications for disaster management and homeland security, to environmental monitoring and providing broadband for developing countries. So far, we have considered a variety of aerial platforms, including airships, balloons, solar-powered unmanned planes and normal aeroplanes -- the latter will probably be particularly suited to establish communications very swiftly in disaster zones."
The final experimental flight will use a US-built Unmanned Aerial Vehicle (UAV) and will take place in Arizona days before the York HAP Week conference at the city's historic King's Manor.