Monthly Archives: January 2014

Unravelling the Web of a Cosmic Creeply-Crawly

Unravelling the Web of a Cosmic Creeply-Crawly

20140109 Ray Villard & Nicky Guttridge of Space Telescope Science Institute —

Cosmic Creeply-Crawly Tarantula Nebula
This huge Hubble Space Telescope mosaic of Tarantula Nebula, spanning a width of 600 light-years, shows a star factory of more the 800,000 stars being born. (20140109) Image by NASA, ESA, and E. Sabbi (STScI)


This new Hubble image is the best-ever view of a cosmic creepy-crawly known as the Tarantula Nebula, a region full of star clusters, glowing gas, and dark dust. Astronomers are exploring and mapping this nebula as part of the Hubble Tarantula Treasury Project, in a bid to try to understand its starry anatomy.

The Tarantula Nebula is located in one of our closest galactic neighbours, the Large Magellanic Cloud. Hubble has released images of this celestial spider several times before: in 2004 (heic0416), 2010 (heic1008), 2011 (heic1105) and 2012 (heic1206). While these images show striking panoramic views of this turbulent region, this new image gives us the deepest and most detailed view yet.

Created using observations taken as part of the Hubble Tarantula Treasury Project (HTTP), this image is composed of near-infrared observations from both Hubble’s Wide Field Camera 3 (WFC3) and Advanced Camera for Surveys (ACS). Due to the combination of infrared filters in this image a purple haze fills the frame, with deep red wisps of dust and bright stars scattered throughout.

This region is an example of an HII region — a large cloud of partially ionised hydrogen within which new stars are being born. Visible to the left of centre is a sparkling star cluster known as R136. It was initially identified as a star, but astronomers puzzled over how one single monstrous star could ionise a giant HII region. However, astronomers later realised it was actually a cluster of stars: a super star cluster.

R136 will eventually become a globular cluster: a spherical ball of old stars that orbits around the centre of its host galaxy. R136 is so massive that it contributes greatly to the Tarantula’s brightness, emitting most of the energy that makes the nebula so visible.

The Hubble Tarantula Treasury Project (HTTP) is scanning and imaging many of the stars within the Tarantula, mapping out the locations and properties of the nebula’s stellar inhabitants. These observations will help astronomers to view the nebula and piece together an understanding of the nebula’s structure [1].

This new image is being released today, 9 January 2014, at the 223rd meeting of the American Astronomical Society in Washington, DC, USA.

Notes
[1] This image of 30 Doradus is also the focal point of an iBook on stellar evolution aimed at children with visual imparments. The book, called “Reach for the Stars: Touch, Look, Listen, Learn” is produced by Elena Sabbi — the lead researcher on this Hubble image — and her collaborators. More information can be found here.



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Are you a cyborg?

Are you a cyborg?

20140107 Kosta Schinarakis of Karlsruhe Institute of Technology —

Communication between man and machine – a fascinating area at the interface of chemistry, biomedicine, and engineering. (Figure: KIT/S. Giselbrecht, R. Meyer, B. Rapp)
Communication between man and machine – a fascinating area at the interface of chemistry, biomedicine, and engineering. Image by KIT/S. Giselbrecht, R. Meyer, B. Rapp

STORY HIGHLIGHTS

Now electronic implants based on microelectronics and semiconductor technology are used in cardiac pacemakers, retina implants, hearing implants, and implants for deep brain stimulation (pain or Parkinson therapies).
Future development area include highly complex neuroprostheses (brain-machine interfaces (BMI)) to allow for the direct physical contacting of the brain.
Future progress in releasing substances by implanted micro- and nanofluidic systems in a spatially or temporarily controlled manner for communication between technical devices and organisms.

They are known from science fiction novels and films – technically modified organisms with extraordinary skills, so-called cyborgs. This name originates from the English term “cybernetic organism”. In fact, cyborgs that combine technical systems with living organisms are already a reality. KIT researchers Professor Christof M. Niemeyer and Dr. Stefan Giselbrecht of the Institute for Biological Interfaces 1 (IBG 1) and Dr. Bastian E. Rapp, Institute of Microstructure Technology (IMT), point out that this especially applies to medical implants.

In recent years, medical implants based on smart materials that automatically react to changing conditions, computer-supported design and fabrication based on magnetic resonance tomography datasets or surface modifications for improved tissue integration allowed major progress to be achieved.

KIT scientists discuss the state of the art of research, opportunities, and risks.



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Intracellular Communication Breakdown May Be Reversible

Intracellular Communication Breakdown May Be Reversible

December 19, 2013 David Cameron of Harvard Medical School —

Sirt1 protein, red, circles the cell's chromosomes, blue.
Sirt1 protein, red, circles the cell’s chromosomes, blue. Image by Ana Gomes

STORY HIGHLIGHTS

• During aging, intracellular communication inside cells between the nucleus and mitochondria breaks down accelerating the aging process.
• This may be reversible.

Mitochondria are often referred to as the cell’s "powerhouse," generating chemical energy to carry out essential biological functions. These self-contained organelles, which live inside our cells and house their own small genomes, have long been identified as key biological players in aging. As they become increasingly dysfunctional overtime, many age-related conditions such as Alzheimer’s disease and diabetes gradually set in.

Researchers have generally been skeptical of the idea that aging can be reversed, due mainly to the prevailing theory that age-related ills are the result of mutations in mitochondrial DNA—and mutations cannot be reversed.

Sinclair and his group have been studying the fundamental science of aging—which is broadly defined as the gradual decline in function with time—for many years, primarily focusing on a group of genes called sirtuins. Previous studies from his lab showed that one of these genes, SIRT1, was activated by the compound resveratrol, which is found in grapes, red wine and certain nuts.

Ana Gomes, a postdoctoral scientist in the Sinclair lab, had been studying mice in which this SIRT1 gene had been removed. While they accurately predicted that these mice would show signs of aging, including mitochondrial dysfunction, the researchers were surprised to find that most mitochondrial proteins coming from the cell’s nucleus were at normal levels; only those encoded by the mitochondrial genome were reduced.

“This was at odds with what the literature suggested,” said Gomes.

As Gomes and her colleagues investigated potential causes for this, they discovered an intricate cascade of events that begins with a chemical called NAD and concludes with a key molecule that shuttles information and coordinates activities between the cell’s nuclear genome and the mitochondrial genome. Cells stay healthy as long as coordination between the genomes remains fluid. SIRT1’s role is intermediary, akin to a security guard; it assures that a meddlesome molecule called HIF-1 does not interfere with communication.

For reasons still unclear, as we age, levels of the initial chemical NAD decline. Without sufficient NAD, SIRT1 loses its ability to keep tabs on HIF-1. Levels of HIF-1 escalate and begin wreaking havoc on the otherwise smooth cross-genome communication. Over time, the research team found, this loss of communication reduces the cell’s ability to make energy, and signs of aging and disease become apparent.

“This particular component of the aging process had never before been described,” said Gomes.

While the breakdown of this process causes a rapid decline in mitochondrial function, other signs of aging take longer to occur. Gomes found that by administering an endogenous compound that cells transform into NAD, she could repair the broken network and rapidly restore communication and mitochondrial function. If the compound was given early enough—prior to excessive mutation accumulation—within days, some aspects of the aging process could be reversed.



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Role of Cloud Formation Underestimated

Role of Cloud Formation Underestimated

20140101 Deborah Smith of UNSW Science Sydney —


President Barack Obama

Global average temperatures will rise at least 4°C by 2100 and potentially more than 8°C by 2200 if carbon dioxide emissions are not reduced, according to new research published in Nature that shows our climate is more sensitive to carbon dioxide than most previous estimates.

The research could solve one of the great unknowns of climate sensitivity, the role of cloud formation and whether this will have a positive or negative effect on global warming.

“Our research has shown climate models indicating a low temperature response to a doubling of carbon dioxide from preindustrial times are not reproducing the correct processes that lead to cloud formation," said lead author from UNSW’s Centre of Excellence for Climate System Science, Professor Steven Sherwood.

“When the processes are correct in the climate models the level of climate sensitivity is far higher. Previously estimates of the sensitivity of global temperature to a doubling of carbon dioxide ranged from 1.5°C to 5°C. This new research takes away the lower end of climate sensitivity estimates, meaning that global average temperatures will increase by 3°C to 5°C with a doubling of carbon dioxide.”

The key to this narrower but much higher estimate can be found in the observations around the role of water vapour in cloud formation.

Observations show when water vapour is taken up by the atmosphere through evaporation the updraughts often rise up to 15 km to form heavy rains, but can also rise just a few km before returning to the surface without forming such rains.

In addition, where updraughts rise this smaller distance they reduce total cloud cover because they pull more vapour away from the higher cloud forming regions than when only the deep ones are present.

Climate models that show a low global temperature response to carbon dioxide do not include enough of this lower-level process. They instead simulate nearly all updraughts rising to 15 km.

These deeper updraughts alone do not have the same effect, resulting in increased reflection of sunlight and reduced sensitivity of the global climate to atmospheric carbon dioxide.

However, real world observations show this behaviour is wrong.

When the processes are correct in the climate model, this produces cycles that take water vapour to a wider range of heights in the atmosphere, causing fewer clouds to form in a warmer climate. This increases the amount of sunlight and heat entering the atmosphere and increases the sensitivity of our climate to carbon dioxide or any other perturbation.

When water vapour processes are correctly represented, the sensitivity of the climate to a doubling of carbon dioxide – which will occur in the next 50 years – means we can expect a temperature increase of at least 3°C and more likely 4°C by 2100.

“Climate sceptics like to criticise climate models for getting things wrong, and we are the first to admit they are not perfect, but what we are finding is that the mistakes are being made by those models which predict less warming, not those that predict more,” said Professor Sherwood.

“Rises in global average temperatures of this magnitude will have profound impacts on the world and the economies of many countries if we don’t urgently start to curb our emissions."


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