June 2008 Archives

Mars Once, On the Waterfront

A Face that Sticks in Your Mind

Why is the crust of Mars up to 30 kilometers thinner on one half of the planet than the other, one side of the planet rugged terrain, the other plains? Twenty-five years ago a couple US scientists theorized that a collision had impacted the planet in a way that caused the dichotomy between the two hemispheres. However geological tools couldn't validate the theory, which also wasn't the only possible explanation.

Mars' mantle, like Earth's, shifts over time, and an alternate theory was that the 30km difference was due to upwards shift of the mantle. Overturn from magma ocean melting could have also produced the differences. Then some scientists thought that an impact of great magnitude would create different features from those found, or would simply obliterate all evidence.

Last week Nature (subscription) published studies by three research groups who used new modeling techniques to provide evidence for the collision theory. Jeffrey Andrews-Hanna, Maria T. Zuber, and Bruce Banerdt's team from MIT estimated that >4 billion years had passed since the Mars dichotomy formed, and that in the intervening time geological activity had obscured evidence from the original event. They programmed specific assumptions about gravity and terrain into their model to account for changes such as activity from Mars' Tharsis volcanic range.

The group then determined the original boundaries of the dichotomy, which happened to match their measurements of the elliptical area formed by the theorized impact. The huge elliptical area formed in the event is 10,600 by 8,500 kilometers (6,586 X 5,281 miles) covers about 20% of the planet and is bigger than than largest country on Earth -- Russia's width is ~5,000 miles. At about the same time as the Mars collision a similar event occurred on Earth which threw off the moon and lots of debris. It was a violent time in the solar system.

Margarita M. Marinova et al., from California Institute of Technology and University of California (UC), Santa Cruz, used modeling to determine the type of impact that would create the unique geology, The team calculated that an object 1,600-2,700 km wide hit the planet with about 3 X 1029 Joules of energy. Scientists believe that the collision not only created a giant crater and changed the planet's crust, but that it was responsible for some of the other features of Mars. F. Nimmo and team, also from UC Santa Cruz, produced a third study to round out current understanding of the possible impact.

What's The Problem on the Water Front?

In other exciting Mars news, robots earlier in the month discovered what looked like it could be ice. Scientist programmed robots had taunted us for years, foraying around the planet then duly reporting back no signs of water. Last weekend the "NASA Phoenix Mars Lander" scooped up some of the icy soil for analysis. By vaporizing it in an oven analyzing the gases emitted, and by determining the minerals in the clumps of icy soil retrieved by the robot, scientists will try to ascertain what the substance is, whether it was at some time liquid, and how it formed. The lab tried to run this experiment a few weeks ago, but it went awry when the robot deposited the soil into the oven but the oven reported back that the soil wasn't there. Scientists were planning to process the soil sample differently or use a different oven in order to complete the analysis.


Acronym Required previously wrote about Mars in "Mars Global Surveyor Bites the Dust".

Presidential Privy Power

For years it seems, people have heard reports like the recent one by the Justice Department inspector general and the Office of Professional Responsibility, which found the Department of Justice hiring practices had discriminated against lawyers who were "leftist", identified by those who were members of Greenpeace, the Poverty and Race Research Action Council, or the American Constitutional Society. Others have felt helpless in the face of leadership on science, democracy, and the environment. Like when the Bush Administration refused to comply with the Supreme Court's order that the EPA must act to regulate emissions. And today the bad news continued on this matter when the D.C. Circuit Court refused to set a deadline for the EPA that the states had petitioned the court for -- leading us to wonder -- are the two connected?

With some end in sight perhaps, a few citizens are making it their mission to strike back, albeit symbolically (and perhaps emboldened by the imminent term end). There's the Bush Legacy Bus -- I'm sure you've heard -- which is touring 150 cities this summer, first stop yesterday in Dayton, Ohio. The group promises not to let memories of the presidency fade into the twilight of his last term and hopes to influence the outcome of the elections. Less bombastically, and no doubt by mistake, The New York Review of Books advertising arm has sent out a leaflet for "$80 SAVINGS" off the price of a year's subscription, and a "FREE GIFT", the book "The Consequences to Come: American Power After Busch"[sic].

As well, a San Francisco group launched a petition drive to put an initiative on the ballot that would rename the Oceanside Water Pollution Control Plant the George W. Bush Sewage Plant. Some find it fitting, but not everyone thinks it's funny. Howard Epstein, chair of the San Francisco Republican Party promised to do everything in his power to stop the measure from going through, calling it "loony bin direct democracy." The spokesman for the San Francisco Public Utilities Commission was also not too keen on the idea, because the the plant is highly efficient and award-winning: "If you are looking for a place to make a negative statement about the Bush administration's impact on the environment, this would be the last place to do it", he said.

What's Your Sign Code?

It's better than astrology and all the rage. Genetic testing offered as a gamut of services, under marketing rubrics along the lines of "Discover Your True Self!" Some of this discovery is whimsical, for instance, the company 23andMe offers visitors to their website graphics and insight on the percentage of people in their company prone to wet ear wax, not flaky, determined by a dominant allele. Some tests are more diagnostic, claiming to promote health. Salugen touts the fantastic slogan "DNA Customized Nutrition" and offers vitamins with their DNA testing. The Genelex website says DNA testing can be used to fine tune the dose of prescription drugs used for treatment of diseases like depression, cancer and epilepsy. Its a burgeoning, unexplored, market. How will it evolve?

A couple of weeks ago, the California Department of Public Health sent cease-and-desist notices to 13 gene testing services, warning the companies not to offer tests to California consumers. New York state took similar action last November, sending notices to 31 companies. The California notice references a state code that makes it "unlawful for any person to own, operate, maintain, direct, or engage in the business of operating a clinical laboratory, as defined this chapter, unless she or she possesses a valid clinical laboratory licensed issued by the department." The department also objects to tests being ordered without a physician. Some companies have stopped selling services to customers in these states but others continue their business, undaunted, claiming that what they're offering is not subject to the states' rules.

The companies are doing more than selling to consumers though. In addition to offering genetic screens for curiosity or personal health, companies are moving to use the collected data to advance research. 23andMe is collaborating with the Parkinson's Institute to provide information from its customers to help understand that disease. This is in line with some of the company's long term goals, according to the San Francisco Chronicle:

"If 23andMe eventually succeeds in hosting large-scale communities of members with various illnesses, it can become a conduit for pharmaceutical companies that would pay the company to relay their offers to participate in clinical trials [co-founder Linda Avey] said."

Google and Microsoft are also in the process of setting up systems to gather large data sets from patients, a move that may help accelerate understanding of diseases. But there are many unanswered questions about the use and usefulness of the data.

Some say that federal regulation is so scarce and the barrier of entry so low that the direct to consumer industry invites fraudulent players. Others ask what such predictive tests can really predict? One woman interviewed by the journal Nature (453: 570-571) said her test results showed a 34% chance of becoming obese, compared to the average female her age who had 32% chance. Some researchers and public policy advocates ask whether the tests are a waste of money.

Even if the tests are predictive, will they encourage people to change their habits, or is that wishful thinking? Most people know that obesity increases your risk of heart attack, diabetes, cancer, etc. But despite straightforward evidence provided by daily surveillance in low cost mirrors, the western population suffers an epidemic of obesity not stanched by the most accessible information. Will more tests convince people to exercise and eat their vegetables?

Like many health conditions, obesity is not solely determined by genes. But while everyone acknowledges the influence of environment on disease probability, the extent of the influence is unknown. The same caveat applies to genetic influences. Huntington's disease is one disease largely determined by genetics, while autism and many others vary as to the genetic influence. Yet the proliferation of these companies encourages public perception that genetics is extraordinarily predictive of health outcomes.This can be problematic for individual consumers who could be misled about the importance of the data. The implications of incomplete information in the form of genomic data could also problematic when companies start collecting data for analysis.

Some genetic testing companies claim that the information they're providing to consumers is not diagnostic, only informational, they market the information as empowering to the consumer. But companies' collective enthusiasm for getting their hands on the forthcoming data belies their claims that the tests are solely for their customers' curiosity. The value of this information is far greater to the company that amasses collections of individual data than it is to any one individual. And once a company has data that represents recurring revenue potential, how is that information not just as fluid and salable as names, telephone numbers and addresses?

What are the implications of this? On the lighter side, imagine being besieged with junk mail about summer diet camps because at age nine, it's revealed that you show a propensity for Type II diabetes based on your mother's profile. Or imagine you pay to query your risk of arthritis and agree to have this data used by certain parties (identifying information stripped, of course). But then your emails begin to feature ads for joint balms or extra absorbent Q-tips. Can't imagine it?

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