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In this issue:
Where the LCLS Ends: The XCS Instrument
President Obama Addresses the National Academy of Sciences, Launches Science Policy Forum
Colloquium Today: A Water Crisis for a Billion People

SLAC Today

Monday - April 27, 2009

Where the LCLS Ends: The XCS Instrument

(Photo - the LCLS XCS team)
Members of the LCLS XCS team stand in the Far Experimental Hall. (From left: engineers Michael Kosovsky and Ted Osier, instrument scientist Aymeric Robert and engineer Eric Bong. Not pictured: engineer William Nolan and DESY visiting scientist Soo-Heyong Lee. (Photo by Brad Plummer.)

The Linac Coherent Light Source will pack a wallop. When it begins operation later this year, the LCLS will provide 10 trillion X-ray photons in a flash of about 100 femtoseconds—a quadrillion times faster than accomplished by today's best storage-ring-based synchrotron lightsources. When these powerful bursts of X-ray light reach the LCLS Far Experimental Hall in 2012, they will for the first time encounter the X-Ray Correlation Spectroscopy instrument, XCS for short. Using the powerful LCLS beam and a new extension of an experimental technique, the XCS will allow researchers to observe dynamical interactions within molecules on very short time scales.

"This instrument will let us investigate nanoscale dynamics," said XCS Instrument Scientist Aymeric Robert. "We'll be looking at fundamental molecular motion on a very short time and length scale."  Read more...

President Obama Addresses the National Academy of Sciences, Launches Science Policy Forum

(Photo - President Barak Obama)

This morning, President Barack Obama addressed members of the National Academy of Sciences at the academy’s 146th annual meeting in Washington, DC. The academy announced it will post audio and video recordings of the speech to the NAS Web site.

The president's address came closely after the launch of a new Office of Science and Technology Policy blog,  intended as a vehicle for conversation and public comment on the president's March memorandum on scientific integrity. According to the White House blog, the president provided this context in his remarks today:

On March ninth, I signed an executive memorandum with a clear message: Under my administration, the days of science taking a back seat to ideology are over. Our progress as a nation – and our values as a nation – are rooted in free and open inquiry. To undermine scientific integrity is to undermine our democracy. It is contrary to our way of life.
That’s why I have charged John Holdren in the White House Office of Science and Technology Policy with leading a new effort to ensure that federal policies are based on the best and most unbiased scientific information. I want to be sure that facts are driving scientific decisions – and not the other way around.
As part of this effort, we've already launched a Web site that allows individuals to not only make recommendations to achieve this goal, but to collaborate on those recommendations; it is a small step, but one that is creating a more transparent, participatory and democratic government.

Colloquium Today:
A Water Crisis for a Billion People

(Image - SLAC Colloquium banner)

Today at 4:15 p.m. in Panofsky Auditorium, Stanford Professor of Soil Biogeochemistry Scott Fendorf will present "A Water Crisis for a Billion People: Pathogen and Poison Infected Waters of Asia."

Conservatively, there are more than 1.2 billion people who lack access to safe drinking water. More than 700 million of them live in South and Southeast Asia. The problem is not a lack of water but a lack of safe water—it’s the water quality, not quantity in this region of the world.

On a global level, the prime culprit for degraded water quality is use of pathogen infested surface water. In South and Southeast Asia, the problem is exacerbated by contamination with arsenic. At present, more than 140 million people are being poisoned by drinking arsenic-laced groundwater, and the problem is growing. Arsenic is naturally derived from eroded Himalayan sediments which are transported down the major river systems and deposited in the low-lying regions.

Through measurements in Cambodia, Fendorf's group has revealed that arsenic is released from near-surface, river-derived sediments and slowly transported through the underlying aquifer and then back to the river. The team's results represent a model for understanding pre-disturbance conditions for the major deltas of Asia and offer the ability to predict aquifer responses to currently changing land uses.

Professor Scott Fendorf leads the soil and biogeochemistry group within the School of Earth Sciences at Stanford University. He is interested in the chemical and biological processes that control the fate and movement of elements, ranging from carbon to arsenic to uranium, within soils, sediments, and surface waters. His talk is free and open to all.

Subscribers to Nature can read about Fendorf's work tracking arsenic from the Himalayas to southeast Asia's water supply in the July 2008 issue.

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