1. UNEARTHING THE STRUCTURE OF HUMIC SUBSTANCES
by Lori Tamura
(Contact: smyneni@princeton.edu)

Formed by the biochemical transformation of plant and animal residue, humic substances (HSs) constitute a major fraction of the dissolved and particulate organic matter in natural ecosystems. The ubiquitous presence of HSs, combined with their ability to provide multiple sites for chemical reaction, makes them relevant to numerous biogeochemical processes such as mineral weathering, nutrient bioavailability, and contaminant transport. The reactivity of HSs depends on their functional group chemistry and structure, which are in turn influenced by the composition of the surrounding media. Researchers from Princeton University, the University of Puerto Rico, and Berkeley Lab have used the high-resolution x-ray microscope at Beamline 6.1.2 to perform in-situ studies of how changes in surrounding media affect the structure of HSs.

Read the full story at http://www-als.lbl.gov/als/science/sci_archive/humic.html.

Publication about this research: S.C.B. Myneni, J.T. Brown, G.A. Martinez, W. Meyer-Ilse, "Imaging of Humic Substance Macromolecular Structures in Water and Soils," Science 286, 1335 (1999).

2. PHYSICAL SCIENCES INDEPENDENT INVESTIGATOR PROPOSALS DUE JUNE 1
(Contact: GFKrebs@lbl.gov)

June 1, 2000, is the deadline for independent investigator (II) proposals in the physical sciences for the next running period, which will last from December 2000 to May 2001. The Independent Investigator Proposal and Request for Beamtime form can be obtained from the User Services Office or on the Web at http://www-als.lbl.gov/als/quickguide/independinvest.html. Investigators who would like to keep a previous proposal active must fill in a one-page Experiment Report/Beamtime Request and submit it to the User Services Office by the June 1 deadline. (The information above does not apply to protein crystallography proposals, which have a separate process and schedule.) All II proposals have the option to remain active for two years (i.e., four six-month cycles) with the submission of an Experiment Report/Beamtime Request every six months.

The numeric rating for each II proposal will be communicated to the investigator along with comments from the Proposal Study Panel (PSP). The cutoff rating for each beamline in the previous proposal cycle is published on the Web at http://www-als.lbl.gov/als/quickguide/pspscores.html.

Information on the proposal process and a summary of the proposal deadlines for both physical sciences and protein crystallography are available at http://www-als.lbl.gov/als/quickguide/independinvest.html. Data sheets describing the capabilities of the beamlines at the ALS are also on the Web at http://www-als.lbl.gov/als/als_users_bl/datasheets.html.

To request a proposal form by mail, contact
Ruth Pepe, ALS User Services Administrator
Tel: (510) 486-5268
Fax: (510) 486-4773
Email: alsuser@lbl.gov

3. ALS DRAWS CROWDS AT OPEN HOUSE 2000

A steady stream of science enthusiasts of all ages passed through the doors of the ALS, opened to the public on Saturday, May 6, as part of Berkeley Lab's Open House 2000. Thousands of intrepid visitors braved threatening skies for the rare chance to learn more about what goes on up in the Berkeley Hills under the big ALS dome and other Lab buildings. Near the cafeteria and administration building, "game" booths (cleverly designed to illustrate scientific principles), food stands, souvenirs, and live music all contributed to the relaxed, carnival atmosphere.

On the ALS patio, crowds were drawn to "Cool Science" demonstrations of the strange effects of high vacuum and low temperature. Nearby, in the ALS parking lot, high-energy "electrons" (kids) ran through an obstacle course modeled after the ALS storage ring in "An Electron Adventure," and the mechanically inclined got the chance to dismantle, with impunity, computer hard drives and other electronic equipment at "The Electronics Petting Zoo." The ALS lobby featured historical and informational displays, highlighted by the premiere of a short, introductory video about the ALS. Inside, guided tours of the x-ray microscope (Beamline 6.1.2) and the Macromolecular Crystallography Facility (Beamline 5.0.2) introduced visitors to the study of life sciences at the ALS, and a darkened conference room created just the right atmosphere for interactive exhibits about x rays, polarized light, and monochromators.

Many, many thanks to Liz Moxon, the ALS Open House coordinator, and all the ALS volunteers who helped make Open House 2000 a success.

4. HEAD OF OPERATIONS GROUP RETIRES
(Contact: B_Feinberg@lbl.gov)

Bob Miller, the ALS Operations Group leader, retires this month, with many thanks and best wishes from the entire ALS community. He has done a superb job, not only as head of the Operations Group, but as a patient, accessible, and dependable source of information for the ALS in general. Bruce (Sam) Samuelson, a former electronic maintenance technician and, most recently, an accelerator operator, has been tapped to be the new Operations Group leader. During a brief transition period, Joe Harkins, who coordinates the many facilities projects at the ALS, will lead the Thursday maintenance scheduling meetings and Gary Krebs, the User Services Group leader, will handle the machine scheduling activities. Over the next several months, Sam will be phased into these roles as well. Congratulations to Sam, and welcome to this new, challenging position.

5. UEC CORNER: NOTES FROM THE USERS' EXECUTIVE COMMITTEE
by Nora Berrah
(Contact: berrah@wmich.edu)

The UEC has begun organizing this year's Users' Meeting, to be held on October 16-18, 2000. This year, we are planning to try a different format by having a keynote speaker and several recent research highlights on the first day. The second and, if necessary, third days will consist of specialized sessions or workshops that will run in parallel. Please send us your suggestions for speakers and workshops and let us know if you want to organize a workshop.

6. WHO'S IN TOWN

Following are some of the experimenters who will be collecting data during the next two weeks at the ALS.

Beamline 1.4.3
Ted Raab (Univ. of Colorado at Boulder)
Felicia Hendrickson and Bob Glaeser (Univ. of California, Berkeley, and Berkeley Lab)
Phil Huie and Dan Fletcher (Stanford Univ.)
Hoi-Ying Holman (Berkeley Lab)
Karl Nieman and Ron Sims (Utah State Univ.)
Mary Kauffman (Idaho National Engineering and Environmental Laboratory)
Ken Ward (Hewlett-Packard Company)
Jessica Preciado, Ralph Greif, and Boris Rubinsky (Univ. of California, Berkeley)

Beamline 3.3.2
Keith Jackson and Cheryl Hauck (Berkeley Lab)

Beamline 6.1.2
Peter Fischer (Univ. of Würzberg, Germany)

Beamline 7.3.1.1
Othon Monteiro (Berkeley Lab)

Beamline 8.0.1
Steve Cramer (Univ. of California, Davis)
Miguel Salmeron (Berkeley Lab)
Eberhard Umbach (Univ. of Würzburg, Germany)

Beamline 10.0.1
Eli Rotenberg (Berkeley Lab)
François Wuilleumier and coworkers (LURE and Univ. Paris-Sud)
Scot Kellar, Z.X. Shen, and coworkers (Stanford Univ.)

7. OPERATIONS UPDATE
(Contact: EJLampo@lbl.gov)

Beam reliability for the last two weeks (April 24 - May 7) was 96% for user shifts. There were no significant outages.

Long-term and weekly operations schedules are available on the Web (http://www-als.lbl.gov/als/accelinfo.html). Requests for special operations use of the "scrubbing" shift should be sent to Gary Krebs (GFKrebs@lbl.gov, x7727) by 1:00 p.m. Friday. The Accelerator Status Hotline at (510) 486-6766 (ext. 6766 from Lab phones) features a recorded message giving up-to-date information on the operational status of the accelerator.