The atmospheric X-ray imaging spectrometer (AXIS) instrument: Quantifying energetic particle precipitation through bremsstrahlung X-ray imaging.

The Atmospheric X-ray Imaging Spectrometer (AXIS) described in this work is a compact, wide field-of-view, hard x-ray imager. The AXIS instrument will fly onboard the Atmospheric Effects of Precipitation through Energetic X-rays (AEPEX) 6U CubeSat mission and will measure bremsstrahlung x-ray photons in the 50-240 keV range with cadmium-zinc-telluride (CZT) detectors using coded aperture optics. AXIS will measure photons generated by energetic particle precipitation for the purpose of determining the spatial scales of precipitation and estimating electron precipitation characteristics. This paper describes the design and testing of the AXIS instrument, including a summary of simulations performed that motivate the shielding, optics, and mechanical design. Testing and characterization is reported that validates the instrument design and shows that the instrument design meets or exceeds the measurement requirements necessary for AEPEX mission success.

Magnetism and magnetoresistance in the critical region of a dilute ferromagnet.

We present detailed experimental measurements and simulations of the field-dependent magnetization and magnetoresistance in the vicinity of the Curie temperature in the highly disordered dilute ferromagnetic semiconductor (Ga,Mn)As. The observed dependence of the magnetization on external magnetic field and temperature is consistent with three-dimensional Heisenberg equation of state calculations including a narrow distribution of critical temperatures. The magnetoresistance shows a peak at the Curie temperature due to the suppression of magnetic scattering in an applied magnetic field, which is well-described by considering changes in the square of the magnetization induced by the magnetic field.

What states are doing to control health insurance costs.

Like other employers, state governments are struggling with continued health care cost increases. A 50-state survey reveals that these large public employers are actively attempting to control the cost of their plans while ensuring quality and a commitment to their employees' overall good health.

Management of hypertension in Mamre women.

A follow-up study was conducted in December 1987 on all 136 women between the ages of 25 and 64 years who had been recorded as being on treatment for hypertension in the Mamre Community Health Project in December 1986. A further 136 women were randomly selected from the same age category to determine the overall prevalence of hypertension. The repeatability and validity of the 1986 project questionnaire were satisfactory. The overall prevalence of hypertension in Mamre women was 25.9% (16.1% for the age group 25-44 years and 38.4% for the age group 44-64 years). The extent of underdiagnosis of hypertension in the community on the basis of the 1986 survey was 56.8%. Despite a good reported compliance rate of 72.7%, 56.3% of hypertensives were not adequately controlled. The Mamre community presents an ideal setting for an interventive study in the management of hypertension.

Estrous cycle patterns in cattle monitored by electrical resistance and milk progesterone.

An electronic probe with parallel stainless steel electrodes was designed to measure changes in electrical resistance in the anterior vagina associated with increased cervical mucus secretion at estrus. Three groups of Holsteins were probed, and a sample of residual milk after milking was taken for progesterone assay every 2nd day for 28 to 40 days. Group I consisted of 29 cycling virgin heifers, Group II consisted of 24 lactating cows in the Cornell herd, and Group III consisted of 62 lactating cows in three commercial herds. Lactating cows were 26 or more days postpartum when sampling began. In Group I, 77% of the measurements at the ventral surface of the anterior vagina were lowest on the day of estrus and correlated well with days KaMaR Heatmount Detectors were triggered or chalk was erased. In Groups II and III, average electrical resistance also was minimal at estrus and was correlated .92 to .99 with average milk progesterone during the 4 days preceding and including estrus. The electronic probe appears to enable one to detect which cows are cycling normally and to aid in determining when to expect estrus.

Pregnancy rate in dairy cows inseminated on the basis of electronic probe measurements.

A new vaginal probe with two pairs of parallel electrodes 90 degrees apart was designed with a switching arrangement so that electrical resistance (ohms) of the dorsal and the ventral areas of the anterior vagina could be monitored separately during the estrous cycle. Three inseminators probed cows during February--April, 1977, in nine herds in stanchion barn housing. Cows not seen in estrus by 40 to 60 dyas after calving were probed every 3rd day. At each dairyman's option normal cows with a low porbe reading were inseminated. Controls consisted of cows seen in estrus by the dairyman and reported for insemination in the routine manner. The diagnosed pregnancy rate for 86 first service controls was 49% versus 52% for 58 cows not seen in estrus, but identified by low probe readings. Cows varied in electrical resistance at breeding, but the fact that pregnancy rates were equivalent in the two groups is interpreted to mean that the probe was as effective in identifying cows suitable for insemination as was visual observation of estrus by dairymen.