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AGRICULTURE'S BIG LEAGUES: If California were a country, it would rank fifth to ninth among the world's nations in the value of its agriculture, according to a report by the UC Agricultural Issues Center.

The unpublished report, , is intended as the fifth chapter in a forthcoming book, The Measure of California Agriculture. The center staff posted the report online so that other researchers and policy analysts could begin to use the data.

"California agriculture is large, diverse, complex and dynamic," said center director Daniel Sumner, a professor of agricultural and resource economics at ºÙºÙÊÓƵ. "It contributes significantly to the economies of the state and nation."

The report found that California farms and related processing industries generate 7.3 percent of the state's private-sector jobs and account for 5.6 percent of labor income. The calculations include ripple effects. They are based on an analysis of data from the 2002 U.S. Census of Agriculture, the most recent census available.

In addition to looking at the state as a whole, the report analyzes agriculture's economic impact on the Central Valley, San Joaquin Valley, Sacramento Valley and Central Coast regions of California.

-- Claudia Morain

OLD SAMPLES, NEW DISCOVERY: ºÙºÙÊÓƵ researchers studying 40-year-old sediment samples have found evidence for magnetic field vortices in the Earth's core beneath the South Pole. The results contrast with earlier studies at lower latitudes, and could lead to a better understanding of processes in the core.

The samples, collected by the U.S. Navy in the Antarctic Ross Sea as part of Operation Deep Freeze, cover almost 2.5 million years of the Earth's history. Geology professor Ken Verosub discovered the samples in storage at the Antarctic Marine Geology Research Facility in Florida and brought them to Davis for magnetic analysis of fine grains. The grains had come from the land -- where the weather beats down on rock, chipping off flakes that wash out to sea and settle to the bottom.

Magnetic grains like these tend to align themselves with the Earth's magnetic field as they settle through the water column. That ancient record can be precisely dated by comparison to other rocks, and gives information about the behavior of the planet's magnetic field in the distant past.

"I think this is one of the best palaeomagnetic records yet from the Ross Sea," said Verosub, whose ºÙºÙÊÓƵ colleagues on the study were graduate student Luigi Jovane and postdoctoral researcher Gary Acton.

They found that there was more "scatter" in the magnetic directions than would be predicted, based on what is known about the Earth's magnetic field from cores collected closer to the equator.

But the results compared well with recent computer simulations of fluid movement in the planet's core, which predict the existence of vortices in the magnetic field near the poles, Verosub said.

A paper describing the research has been published online by the journal Earth and Planetary Science Letters, and is scheduled to appear in the journal's March 30 print edition.

-- Andy Fell