Determination of Omega_b From Big Bang Nucleosynthesis in the Presence of Regions of Antimatter

Production of regions of antimatter in the early universe is predicted in many baryogenesis models. Small scale antimatter regions would annihilate during or soon after nucleosynthesis, affecting the abundances of the light elements. In this paper we study how the acceptable range in Omega_b changes in the presence of antimatter regions, as compared to the standard big bang nucleosynthesis. It turns out that it is possible to produce at the same time both a low 4He value (Y_p < 0.240) and a low D/H value (D/H < 4e-5), but overproduction of 7Li is unavoidable at large Omega_b.Comment: 9 pages, PRD version, ref. 6 correcte

High Spatial Resolution Fast-Neutron Imaging Detectors for Pulsed Fast-Neutron Transmission Spectroscopy

Two generations of a novel detector for high-resolution transmission imaging and spectrometry of fast-neutrons are presented. These devices are based on a hydrogenous fiber scintillator screen and single- or multiple-gated intensified camera systems (ICCD). This detector is designed for energy-selective neutron radiography with nanosecond-pulsed broad-energy (1 - 10 MeV) neutron beams. Utilizing the Time-of-Flight (TOF) method, such a detector is capable of simultaneously capturing several images, each at a different neutron energy (TOF). In addition, a gamma-ray image can also be simultaneously registered, allowing combined neutron/gamma inspection of objects. This permits combining the sensitivity of the fast-neutron resonance method to low-Z elements with that of gamma radiography to high-Z materials.Comment: Also published in JINST: http://www.iop.org/EJ/abstract/1748-0221/4/05/P0501

Yield of Forage Sorghum, \u3ci\u3eSorghum vulgare\u3c/i\u3e, as Influenced by Row Number, Width, and Orientation

The primary objectives of this study were to: (1) obtain an estimate of the degree to which inter-plot competition exists in forage sorghum yield trials; and (2) provide a basis for suggesting corrective measures. The row arrangements required to achieve the primary objective provided an opportunity to study the response of forage sorghum to different row spacings. The elimination of inter-plot error, boarder effect, is essential to proper interpretation of data from experimental agronomic units or plots. Economics either from the cost of labor aspects often determine plot size. Frequently forage sorghum, Sorghum vulgare (Pers.) yield influence of tall, (T) or short (s) growing varieties on neighboring plots of the opposite height character were examined during 1963, 1964, and 1965 at Lincoln, Nebraska and Manhattan, Kansas. Tests were established to measure the interactions of these height variables with row spacing and orientation and soil moisture conditions. Advisor: William L. Colville

Optimization of Vancomycin Dosing to Achieve Target Area Under the Curve in Pediatrics

OBJECTIVE Vancomycin dosing requirements to achieve a target area under curve/minimum inhibitory concentration (AUC/MIC) of 400 to 600 mg•hr/L have not been established in pediatrics. Dose modeling studies and recent guidelines suggest dosing higher than historical recommendations. This study examines dosing requirements to achieve target AUC/MIC in human pediatric patients. METHODS This retrospective study includes 77 patients, aged 1 month to 18 years, at a single center, who received at least 2 days of intravenous vancomycin with a pharmacokinetic monitoring note and calculated AUC/MIC. Dosing to achieve target AUC/MIC was evaluated by age and indication. Nephrotoxicity was also assessed. RESULTS The mean dose required to achieve target AUC/MIC for all patients was 67.7 mg/kg/day. Adjusting for age, the mean dose required to achieve target AUC/MIC of 400 to 600 mg•hr/L was found to be statistically significantly different among 3 age cohorts: 1 month to 5 years, 6 to 12 years, and 13 to 18 years [F(2,74) = 15.32, p &amp;lt; 0.001], with mean requirements of 79 ± 14.1, 65.6 ± 21.1, and 53.9 ± 17.1 mg/kg/day, respectively. Dosing requirements were also found to be statistically significantly different across indications [F(6,70) = 4.84, p &amp;lt; 0.001]. Acute kidney injury was identified in 5 patients (6.5%). CONCLUSIONS The vancomycin dose required to achieve target AUC/MIC in pediatrics was significantly higher in younger pediatric patients and ranged from 53.9 to 79 mg/kg/day, confirming recent guideline recommendations. Doses can be further adjusted for indication. Nephrotoxicity rates remain low compared with historical rates with single trough monitoring. </jats:sec