Natural Sciences

California’s mining and industrial history have led to an excessive build-up of mercury in the Bay Area. As one of the top ten pollutants of the world, this toxic heavy metal has troubling implications for human and environmental health. Although mercury is relatively well studied in aquatic ecosystems, less work has focused on terrestrial animals. However, we know that soil organisms, such as earthworms, accumulate mercury by consuming decaying plant and animal materials in the ground.

Large variations in seasonal temperature and rainfall threaten crop production, food prices, and food security at local to global scales. This project focuses on the impacts of climate variability on Europe’s agricultural regions, with an emphasis on wheat in France. Although France has a relatively small agricultural area, it has among the highest wheat yields in the world. Climateinduced shocks to crop production thus influence global prices for wheat and other commodities linked to wheat through markets.

The goal of the Stanford Solar Observatories Group is to study the origin of solar variability, characterize and understand the Sun's interior and the various components of magnetic activity. To achieve this goal, data analysis is performed from space missions. For a better understanding of the Sun and predictive capabilities for solar activity and space weather, these observations have to be accompanied by realistic numerical simulations of the subsurface flows and magnetic structures of the Sun.

In developed countries about 80% of the total population suffers from acute and 5–10% from permanent lower back pain (LBP). An early diagnosis is crucial to reduce patient suffering and lower the economic burden on the society. In a representative study for the western world, the cost of LBP in Switzerland was estimated at 2.6 billion Euros in 2005. Nevertheless, surprisingly little is known about geometrical abnormalities resulting in LBP. This is in part due to the subtle distinction between healthy geometrical variability and pathological abnormal deformities of the spine.

Symbiosis is a close interaction between different species. The bacteria Wolbachia is the most common endosymbiont (a symbiont living within host cells) described to date. In mosquitoes, Wolbachia induces a form of sterility in crosses between males and females infected with distinct Wolbachia types. This feature makes Wolbachia infection a promising non-chemical tool to reduce human diseases transmitted by mosquitoes. However, the molecular basis of the Wolbachia-induced sterility is still unknown.

The need for chiral compounds has escalated tremendously in recent years as many biological activities, flavors or fragrances are associated with their absolute molecular configuration. In chemistry, chirality (derived from the Greek, "kheir" "hand") refers to molecules that cannot be superimposed on their own mirror images. Historically, chiral compounds were generated by chemical transformation of a chiral precursor obtained from nature's chiral pool.

With the widespread use of satellite imaging, a wealth of information is available to help in the understanding and modeling of earth system processes. In particular, these data play a key role in the analysis of climate variability. However, satellitebased retrievals present spatial discontinuities due to incomplete coverage of the domain resulting from satellite orbital characteristics, or through occlusion by cloud cover and other atmospheric effects. The straightforward use of Geostatistical prediction methods is made impossible by the wealth of the datasets at stake.

Major human migrations during the last several hundred years have generated new populations of mixed European and African ancestry. The Cape Verde archipelago, located near the western coast of Africa, provides one of the earliest examples of this admixture phenomenon, with a complex and well-documented history of contact among European and African populations beginning in the late 15th century.