Month: August 2006

20 year model relieves stress

20 year old model

No…not that kind of model!

“The formation and evolution of dislocation cell structures (patterning) is one of the most important aspects of the deformation process in ductile metals,” according to Lyle Levine and colleagues at the National Institute of Standards and Technology (NIST), Oak Ridge National Laboratory (ORNL), and the University of Southern California. Metallurgists already know that this patterning process arises as clusters of dislocations interact with each other while recent diffraction-resolved studies have shown that the process is initiated by crystal lattice breakup. However, predicting exactly how a metal will behave under stress remains an unresolved problem. Now, Levine and his colleagues have turned to a twenty-year old model to help them out.

Read on…

How to write a successful science thesis

Scientific thesis

This concise guide to the art of writing a scientific thesis demonstrates how you can wring the max. from your results with the min. of effort, at least that’s what the jacket claims.

The book is based on a proven concept that assumes no special writing talent and builds on the model of the previous publication in the series The Art of Scientific Writing. If you’ve got the results and plenty of notes, but no idea how to bring them together to create a degree-winning thesis, then grab a copy of Ebel et al’s latest book.

It’s packed with examples, as well as providing challenging problems to help you organise your thoughts and work.

Perfect for anyone with a term paper, thesis, or dissertation to write. Co-author William E Russey of Juniata College says it will “ultimately lead to better grades”. And, that can be no bad thing.

How to Write a Successful Scientific Thesis available from Amazon

Brain protein unlocked

A key protein linked to neurodegenerative diseases, such as Huntington’s and Alzheimer’s diseases, has been characterised using NMR by US researchers.

John Cavanagh, Douglas Kojetin, David Kordys, and Richele Thompson of North Carolina State University teamed with colleagues Ronald Venters of Duke University and Rajiv Kumar of the Mayo Clinic and Foundation have obtained a structure for the protein, calbindin-D28K. This protein modulates calcium levels by sequestering calcium from areas that have too much or serves as an on/off switch for further chemical reactions. It is found in the kidneys, pancreas, ocular nerve and large amounts are present in the brain. It is its role in the brain as a “bodyguard” against the action of the enzyme caspase-3 that links it to neurodegenerative diseases. By binding to and inhibiting caspase-3, calbindin D28K prevents the formation of damaging plaque and tangle formation in the brain, which are hallmarks of neurodegenerative disease. The structure of this key protein has remained elusive, until now.

Read on…

Bird flu reaches the US

…but it’s not the deadly strain of avian influenza (high-pathogenicity avian influenza, HPAI H5N1) that has featured in endless media speculation over the last couple of years. At a time, when the Thai authorities have announced several new cases of bird flu in their country, scientists in the US have detected the low-pathogenicity (LPAI) bird flu in wild swans near the banks of Lake Erie.

Ron DeHaven, administrator of USDA’s Animal and Plant Health Inspection Service, told the Associated Press that “We do not believe this virus represents a risk to human health.” Preliminary testing showed the presence of the H5 and the N1 sub-types in the infected Michigan birds, but the USDA explains that these are more probably present because of LPAI, which is also known as American H5N1, as opposed to Asian H5N1.

Evidence of this putative low pathogenicity avian influenza (LPAI) has been found on two occasions in wild birds in the United States. In 1975 and 1986, it was detected in wild ducks. These detections occurred as part of routine sampling. LPAI H5N1 has also been detected in Canada, most recently in 2005.

Asian H5N1 has killed at least 140 people but is yet to mutate into a form that is readily transmissable between humans. Indeed, it seems the only likely way you catch this strain is through very close proximity to infected birds (i.e. sharing living quarters) or by coming into contact with feces from an infected bird.

More on the Michigan bird flu story…

Naked podcast

The ‘Naked Scientists’ – as featured on Sciencebase – perhaps don’t deserve the alarming image their name inspires. This radio show and podcast aims to strip science down to its bare essentials and promote it to the general public, says main man Dr Chris Smith, the main aim is to “help people enjoy science as much as we do and, at the same time, to have fun,” he says.

Naked Scientists is produced at the University of Cambridge and broadcast by the BBC, and recently reached 2 million podcast downloads in the last 12 months. On top of that, the show, receives 50,000 downloads per week and has been nominated by its listeners for ‘best science show’ in the 2006 international ‘Podcast Awards’.

Each hour-long edition of the programme sees the presenters encouraging the audience to experiment in their kitchens alongside the radio show and then call in with their results. So far the series has seen listeners build home-made submarines, recreate the sound of Big Ben inside their heads, and simulate an explosion in a custard factory.

Smith, a lecturer at Cambridge, started the programme in 1999 as “ScienceWorld” and in just 7 years has made grown it into a weekly local radio show to become a national and international presence with inputs to network radio across Australia (ABC Radio National) and the UK (BBC Radio Five Live). On the Internet, its companion website www.thenakedscientists.com receives over one and a half million hits per week.

Check out the latest naked science on Sciencebase. Sciencebase now produces its very own podcast – the Geordie Boffin Podcast – an irregular and irreverent look at science from David Bradley.

Bird flu drugs

In the latest issue of The Alchemist on ChemWeb.com I provide a round-up of the week’s chemistry news, of particular importance could be news that UK and Australian researchers may have found a new way to approach drug design for bird flu viruses that precludes drug resistance.

A new drug to fight bird flu that should be able to side-step the emergence of viral resistance is being developed by Andrew Watts of the University of Bath, UK and Jennifer McKimm-Breschkin of CSIRO Australia. Both Tamiflu and Relenza, the two drugs currently being stockpiled by governments in preparation for a global outbreak of bird flu, are inherently susceptible to resistance because of the way they work. Although the new drug acts on the same target as these treatments, the enzyme neuraminidase, it targets a specific region of the enzyme that essential to its function. If this region mutates the virus would no longer be viable, so that resistance cannot emerge.

Read about this and more in this week’s Alchemist.

I should cocoa

Flavanols in cocoa could stave off cardiovascular disease, something that affects almost 78 million baby-boomers in the US alone, according to a paper in the August issue of the Journal of Hypertension.

Researchers at Harvard Medical School and the Brigham and Women’s Hospital in Boston discovered that drinking a standardized flavanol-rich cocoa beverage improved several measures of blood vessel function, especially among older study participants. So, that relaxing chocolate drink at bed-time could be doing a lot of good. Flavanols purportedly improve blood flow and reduce damaging clot formation.

Interestingly, the research was sponsored by chocolate manufacturer Mars.

Read into that what you will.

Lithium

It’s not something Nirvana mentioned in their elemental song, I presume they had other things on their mind, but there isn’t enough lithium in the universe. It’s not that there’s a shortage, it’s just that our knowledge of cosmic and stellar chemistry would suggest that there ought to be more of this alkali metal than there actually is. A paper published in this week’s Nature could offer an explanation.

The problem is that old stars, which ought to be made from a mixture of elements close to the ‘primordial’ blend generated in the Big Bang, don’t appear to have as much lithium as this would require. Although most of the matter produced by the Big Bang was hydrogen and helium, theories of element production predict that there should also be a fair proportion of lithium. But the amount predicted is a factor of two or three times larger than that seen in old stars. This implies that our understanding of the physics either of the Big Bang or of stars – or both – is lacking.

Andreas Korn and colleagues look at 18 stars in a cluster of old stars to see how the elemental content of their atmospheres changes with evolutionary stage. They find that various elemental abundances depend on a star’s temperature. This, the researchers say, is because heavy elements tend to diffuse deep into the star. For those stars that have evolved into giants, the elements are mixed back into the stellar atmosphere by convection, so that the stars’ composition is restored. Not so for lithium: it does not survive the trip through the stellar interior, as it is burnt when temperatures exceed 2 million degrees.

Korn and colleagues estimate that the original lithium abundance in these stars was around 78 percent higher than that suggested by current average values – which is enough to make up the discrepancy with the predicted primordial abundance.

Nature, 2006, 657-659

Search engine bias

Search engines are not biased toward popular and highly linked websites, researchers report, in this week’s PNAS.

The internet is enormous, vast, gigantic, big and complex, search engines have taken on an increased role in guiding users to their destinations (community forums and blogs aside). But there are concerns that search engines, by means of their subjective ranking algorithms, could be creating positive feedback loops wherein popular sites that receive the most hits become more popular and so on. Eventually, this cycle shouldresult in a small subset of websites monopolizing a majority of traffic.

However, according to Santo Fortunato, Alessandro Flammini, Filippo Menczer, and Alessandro Vespignani this doesn’t actually happen. They collected data from various search engines and found that the popularity bias of search engines was weak. Search engines were found to direct less traffic to popular websites compared with a scenario where there were no search engines and all traffic was generated by web surfing.

The key reason for this apparent lack in search engine bias, the researchers note, is the wide diversity and specificity of information sought by internet users, which mitigates the ranking bias of the engine and creates balanced results. “We reconcile theoretical arguments with empirical evidence showing that the combination of retrieval by search engines and search behavior by users mitigates the attraction of popular pages, directing more traffic toward less popular sites, even in comparison to what would be expected from users randomly surfing the Web,” says the team.

So, where does this leave those seeking to tweak their position in the SERPs (search engine results pages) through SEO (search engine optimization) techniques? Your answers are most welcome…

You can read the preprint paper here and at PNAS (once it’s published) here