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In this issue:
Dark Matter—What's Out There?
Safety Today: Protect Against Skin Cancer
Keep Your Cash and Valuables Locked Up
Word of the Week: "Emittance"
Safety Seconds

SLAC Today

Tuesday - August 7, 2007

Michael Peskin recently published a review paper that discusses how scientists are trying to unlock the mysteries of dark matter.

Dark Matter—What's Out There?

For thousands of years, people have gazed at the stars and wondered, "What's out there?" But it wasn't until the 1930s that anyone realized there is much more out there than meets the eye. Recent observations have proven that about 22 percent of the universe is made out of a "dark matter" that is like the wind—although invisible, its influence can be seen. In a recent paper, SLAC Theoretical Physicist Michael Peskin provides an overview of how scientists are trying to unlock the mysteries of dark matter.

Although there are many theories regarding dark matter, one of the popular claims suggests that dark energy is a Weakly Interacting Massive Particle (WIMP). These hypothetical particles rarely interact with visible matter, making them extremely difficult to detect outside of a particle accelerator. WIMPs have not yet been seen in particle accelerators, but that could soon change.

"Scientists have been working on dark matter questions for a long time," said Peskin. "But now the work is all coming to a head."  Read more...

(Column - Safety Today)

Protect Against
Skin Cancer


With summer here, it's important to remember that skin cancer is the most commonly diagnosed cancer in the U.S. It affects more than one million people each year, many of whom are older men and women.

One of the biggest known risk factors for getting skin cancer is excess exposure to ultraviolet (UV) light. UV light increases the risk of all three kinds of skin cancer: melanoma (the least common but most severe), basal cell carcinoma and squamous cell carcinoma. The older you are, the more likely you are to be diagnosed with skin cancer, particularly after age 50. However, increased sun exposure and sun damage at an early age is a major contributor to skin cancer later in life.

One of the best ways to protect against skin cancer is to simply limit exposure to harmful UV light. Avoid the sun during midday, when its rays are the strongest, wear appropriate clothing—such as hats or long-sleeved shirts—and wear plenty of sunscreen with a sun protection factor (SPF) of 30 or higher.

UV light can be just as damaging on a cloudy, overcast day as on a bright and sunny day, so use sunscreen and other protective measures daily, however the sky looks.

This article was originally published in NIH News in Health.

Keep Your Cash and Valuables Locked Up

SLAC Site Security has received three reports of cash missing from unlocked offices within the past few days. SLAC security officers are investigating the circumstances of these incidents.

"Please lock away your purses and wallets, and be certain your office and/or desk is locked when you are not around. These are the best ways to protect your belongings," says Simon Ovrahim, SLAC Site Security Manager.

Word of the Week:
"Emittance"

Emittance is a measure of a beam pulse (electrons, x-rays, jelly beans) that factors in spot size and how much the particles in the beam tend to spread out as they travel. It is an important parameter for users at synchrotron facilities such as SSRL, where the size and power of an x-ray beam spot on a sample determines the precision of many experiments, and BaBar, where small emittance means higher luminosity.

Safety Seconds

The recommended advice for the patient wanting to avoid a medical error is the same as our injury avoidance advice to the SLAC staff—you must always be vigilant. You should try to understand as much as possible about your medical situation—what conditions or diseases you have, what medications you are taking in what dose and why, what treatment doctors are proposing, and ask questions all the time if something does not seem right.

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