Friday, November 26, 2010

Warm Arctic --> Cold Continents

As the Arctic warms, atmospheric changes may paradoxically bring colder winters to North America and Eurasia. If a warm Arctic leads to an early breakup of the polar vortex then the mid-latitudes will be inundated with cold Arctic air during mid-winter but spring comes early since much of the cold air gets dissipated early.

Earth Observatory:stratosphere influences winter weather

Wunderground: winter La Nina forecast

NOAA Arctic "Report Card"

"There is evidence that the effect of higher air temperatures in the lower Arctic atmosphere in fall is contributing to changes in the atmospheric circulation in both the Arctic and northern mid-latitudes. Winter 2009-2010 showed a new connectivity between mid-latitude extreme cold and snowy weather events and changes in the wind patterns of the Arctic; the so-called Warm Arctic-Cold Continents pattern."

Paleorecord of arctic warming indicates these conditions are unprecedented in at least the last few thousand years. For more information on climate change-linked weather anomalies, check out the 2010 drought in the Amazon.

awesome Science visualizations

Science article from February 19th, 2010.

"Biodemography of human ageing"

This article in the March 25th 2010 issue of Nature magazine confounds the rest of that issue's Insight Review of human ageing. For someone not versed in the field of demographic statistics used in this article, the graphs and conclusions are unique. By examining a kind of running average of life expectancy, the author is able to talk about the continuing increase in life expectancy.

"Humans will continue to suffer senescence -- but the process is not intractable. Mortality has been postponed considerably as a result not of revolutionary advances in slowing the process of ageing but of ongoing progress in improving health. If progress in reducing mortality continues at the same pace....then in countries with high life expectancies most children born since the year 2000 will celebrate their 100th birthday -- in the twenty-second century. "

"Brawling Over Mammography"

An interesting debate about the problem of false-positives in medical testing. Obviously, everyone wants to be tested "just in case", but a sensible policy would favor plausibility testing; everyone is not equally likely to have every disease. This article from the February 19, 2010 issue of Science, details the situation surrounding the release of a report by the U.S. Preventive Services Task Force that ran afoul of political accusations of "medical rationing". For women age 40-49 years with no other risk factors, the odds that a positive mammogram is actually due to cancer, rather than a false-positive test, is only about 2%. In other words, for every one breast cancer detection, 50 women are told that they have tested positive on their mammogram.

"Two views of our planet's future"

Nature article by Dr. David Orr, (Oberlin College) in this April 28 2010 review of books written by Stewart Brand and Bill McKibben. Each book advocates societal responses to anthropogenic climate change, with Stewart Brand advocating technological solutions and Bill McKibben advocating local interventions. Dr. Orr has also written his own book on solutions, entitled Down to the Wire: Confronting Climate Collapse.

The article is well written and the even the comments section contains interesting citations by volunteers.

Amino-acid imbalance explains extension of lifespan by dietary restriction in Drosophila

This paper in Nature, December 31, 2009 disproves the theory of resource allocation in which "high survival, associated with dietary restrictino, and high reproductive rate, associated with full feeding, are mutally exclusive." The authors show that different combinations of amino acids are responsible for longevity and fecundity, and that both can occur when either methionine is the only amino acid in the diet or when methionine is excluded from an otherwise normal diet. Therefore, the standard tradeoff observed between allocating resources to repair or growth is based on a nutritional sensing and signalling pathway that must involve methionine.

The authors go on to show that this pathway is the insulin sugar-sensing pathway by knocking out insulin receptors in Drosophila. In the figure above flies expressing a dominant negative called lnRDN (diamonds) live much longer, regardless of diet, than do wildtype (triangles) and control with a deGAL4 promoter (squares). Whether these findings apply to humans could possibly be answered with population nutritional and health data, but these can be hard to access.

Very well written.

Monday, November 15, 2010

Toxic Bodies by Nancy Langston

"Toxic Bodies: Hormone Disruptors and the Legacy of DES" explores why our environment has become saturated with synthetic chemicals that disrupt hormones, and asks what we can do to protect human and environmental health. In this thorough undertaking, Environmental Historian Nancy Langston examines endocrine disruptors as a case study of environmental risk assessment and response. Interesting to compare this book's stance on weight-of-evidence to Our Stolen Future or The Secret History of the War on Cancer by Devra Davis. Compare that to a more formal report by the American Institute for Cancer Research.
Activation of immune system and inflammation mediators (from Holgate 2003)

The Human Immune System is an extremely sophisticated chemical signaling systems, with the capacity to produce almost unlimited variability within a homeostatic regulatory framework that is just being glimpsed. Innate and acquired immunity are mediated by a large number of systems and subsystems, including the complement system, chemokines, cytokines, lipid-signalling molecules, etc. Inflammation, the process of capillary dilation, smooth muscle contraction, and recruitment of immune cells, utilizes seven major pathways.

Cellular and Plasma Inflammation Mediators:

Plasma Inflammation Mediators

COX/LOX Lipid Inflammation Pathway

"It is unclear to what extent the nature of an inflammatory trigger dictates the type of mediator induced. In addition, many (but not all) mediators not only have direct effects on target tissues but also themselves induce the production of additional mediators.
It will be important to understand the logic underlying this hierarchy of mediators."(Medzhitov, 2008)

Seven types of Inflammation Mediators (Medzhitov, 2008):
1. Vasoconstrictive amines: histamine, serotonin
2. Vasoactive Peptides: Substance P, etc
3. Complement Fragments: C3a, C4a, C5a
4. Lipid Mediators: eicosanoids,
5. Cytokines: TNF, IL-1, IL-6, etc
6. Chemokines
7. Proteolytic enzymes

1. Baroody FM, Naclerio RM. Antiallergic effects of H1-receptor antagonists. Allergy. 2000;55(s64):17-27.
2. Holgate ST, Broide D. New targets for allergic rhinitis a disease of civilization. Nat Rev Drug Discov. 2003 November;2(11):903-915.
3. Medzhitov R. Origin and physiological roles of inflammation. Nature. 2008 July 24;454(7203):428-435.

Vital Water and Homeostasis

1. Comparing Oxidative-Reductive Potential (ORP) and pH of various foods and drinks to human body fluids, Okouchi et al (2002). 2. The idea of renal net acid excretion (RAE) indicates that homeostasis in animals is mainained against the intake of heterogeneous substances.

1. Okouchi S, Suzuki M, Sugano K, Kagamimori S, Ikeda S. Water Desirable for the Human Body in Terms of Oxidation-Reduction Potential (ORP) to pH Relationship. Journal of Food Science. 2002;67(5):1594-1598.

2. Remer T. Influence of nutrition on acid-base balance--metabolic aspects. European Journal of Nutrition. 2001 October;40(5):214-220.

Wednesday, November 10, 2010

A Question of Trust

The comments section at the bottom of this July 1 Nature Editorial "A Question of Trust" speak more eloquently to the problem of public perception of climate change science than the editorial itself. Even here, now, at this citadel of learning and knowledge, evidence and peer-review falter before the teeming comment section questioners.

My favorite comment is from the "graduate student" who claims to have an algorithm that, when applied to climate models, disproves every one he's tried it on. And he's even shown it to his advisor, who agrees that this secret algorithm is right, and all peer-reviewed published climate models are hogwash. Genius. Pure, rhetorical genius. What possible response can there be to this kind of nugatory argument?

Wednesday, November 03, 2010

Accountability, Transparency, Scientists and Government

The FDA has promulgated a series of Recommended Daily Allowances (RDA) based on the proprietary review of scientists in the National Academies. The justification for these RDA values are not even available at a large institution such as Ohio State University. Because of this opacity, a large number of people have gravitated to interesting or promising parascientific ideas about the role of vitamins in nutrition. For example, many question the food pyramid's focus on carbohydrates. (Westin A Price) Others argue that the RDA for Vitamin C should be increased by a factor of 10. (Linus Pauling) Or that many health problems can be explained by a deficiency in, for example, iodine. Other groups question whether too much cholesterol is bad, whether too much salt is unhealthy. Much of the creative critiques of establishment medicine is based on rigorous research and reasonably open communication, although usually not entirely peer-reviewed. This gray literature is, however, limited compared to scientific publications. Yet when the scientific process is not transparent, it looses the inherent advantage of demonstrative accountability.

In 1998 Congress broadened the Freedom of Information Act (FOIA) to specify that all government funded science should be shared and freely available to the public. Dr. Sheila Jasanoff, a professor of Science, Technology, and Policy at Harvard University, has recently written an excellent primer in the May 7 2010 issue of Science on her perspective of how climate science measures up; "Policy Forum: Science and Society: Testing Time for Climate Science."

She describes the "Three-Body Problem" as consisting of individuals, reliable bodies of knowledge, and procedures. The individual scientist or expert must be held to high standards of honesty and integrity. In science, peer review partly serves this purpose. Reliable bodies of knowledge create scientific knowledge. Scientific advisory committees translate scientific findings into policy-relevant forms: individual members' impartiality and sound judgment is critical. Under the Federal Advisory Committee Act (FACA) (Public Law 92–463), scientific advisory committees must be fairly balanced and, in the absence of special circumstances, committee meetings and records are presumed to be open to the public.

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