Exploring the Bimodal Solar System via Sample Return from the Main Asteroid Belt: The Case for Revisiting Ceres.

Sample return from a main-belt asteroid has not yet been attempted, but appears technologically feasible. While the cost implications are significant, the scientific case for such a mission appears overwhelming. As suggested by the "Grand Tack" model, the structure of the main belt was likely forged during the earliest stages of Solar System evolution in response to migration of the giant planets.

Oxygen isotope variation in stony-iron meteorites.

Asteroidal material, delivered to Earth as meteorites, preserves a record of the earliest stages of planetary formation. High-precision oxygen isotope analyses for the two major groups of stony-iron meteorites (main-group pallasites and mesosiderites) demonstrate that each group is from a distinct asteroidal source. Mesosiderites are isotopically identical to the howardite-eucrite-diogenite clan and, like them, are probably derived from the asteroid 4 Vesta.

Preferences for schizophrenia treatment outcomes among public policy makers, consumers, families, and providers.

Objective: This study measured state public policy makers' ratings of the importance of several key schizophrenia treatment outcomes and compared them with the ratings of primary stakeholders in schizophrenia treatment.

Methods: Three groups of policy makers (40 administrative decision makers, 40 state legislators, and 20 legislative aides) and three groups of core stakeholders (20 persons with schizophrenia, 13 of their family members, and 20 of their mental health care providers) were recruited in Florida. Participants rated 12 descriptions of schizophrenia-related health states that reflected better and worse outcomes in six domains: psychotic symptoms, deficit symptoms, medication side effects, productive activity, daily activity, and social activity.

Moderators of stress in parents of children with autism.

Parents of children with autism experience more stress and are more susceptible to negative outcomes than parents of children with other disabilities. The present work examines the relationship between stressors, social support, locus of control, coping styles, and negative outcomes (depression, social isolation, and spousal relationship problems) among parents of children with autism. Fifty-eight parents completed surveys.

The elemental composition of asteroid 433 eros: results of the NEAR-shoemaker X-ray spectrometer.

We report major element composition ratios for regions of the asteroid 433 Eros imaged during two solar flares and quiet sun conditions during the period of May to July 2000. Low aluminum abundances for all regions argue against global differentiation of Eros. Magnesium/silicon, aluminum/silicon, calcium/silicon, and iron/silicon ratios are best interpreted as a relatively primitive, chondritic composition.

Discovery of a basaltic asteroid in the outer main belt.

Visible and near-infrared spectroscopic observations of the asteroid 1459 Magnya indicate that it has a basaltic surface. Magnya is at 3. 15 astronomical units (AU) from the sun and has no known dynamical link to any family, to any nearby large asteroid, or to asteroid 4 Vesta at 2.

Spectral Properties of Near-Earth Asteroids: Evidence for Sources of Ordinary Chondrite Meteorites.

Although ordinary chondrite (OC) meteorites dominate observed falls, the identification of near-Earth and main-belt asteroid sources has remained elusive. Telescopic measurements of 35 near-Earth asteroids ( approximately3 kilometers in diameter) revealed six that have visible wavelength spectra similar to laboratory spectra of OC meteorites. Near-Earth asteroids were found to have spectral properties that span the range between the previously separated domains of OC meteorites and the most common (S class) asteroids, suggesting a link.