Worst-case space radiation environments for geocentric missions

Worst-case possible annual radiation fluences of energetic charged particles in the terrestrial space environment, and the resultant depth-dose distributions in aluminum, were calculated in order to establish absolute upper limits to the radiation exposure of spacecraft in geocentric orbits. The results are a concise set of data intended to aid in the determination of the feasibility of a particular mission. The data may further serve as guidelines in the evaluation of standard spacecraft components. Calculations were performed for each significant particle species populating or visiting the magnetosphere, on the basis of volume occupied by or accessible to the respective species. Thus, magnetospheric space was divided into five distinct regions using the magnetic shell parameter L, which gives the approximate geocentric distance (in earth radii) of a field line's equatorial intersect

An evaluation of the logistics functions of the Chemical Specialties Division, Ralston Purina Company

This study was originally designed to examine the Chemical Specialties Division of the Ralston Purina Company and to make recommendations concerning the development of a more efficient distribution system for the products of the Division. During the course of the examination, the Ralston Purina corporate management announced plans to terminate all national sales of the Chemical Specialties Division. In doing so, the corporate management terminated all ’’outside” sales and limited the functions of the Chemical Specialties Division to supplying the necessary chemical cleaners to Ralston Purina1 s plants. This eliminated any need for a more efficient distribution program required to maintain a competitive position in chemical specialty sales since all products would now be distributed only to Ralston Purina plants within the corporate distribution system. As a result of this decision on the part of Ralston Purina1 s corporate management, the original purpose of this study -- to develop and recommend improvements in logistical management for the Chemical Specialties Division keyed to competitive requirements of a national sales market -- was lost and the objective was changed to the development of the requirements for an effective and efficient distributive system for a small division within a large corporation, using the experience of the Chemical Specialties Division as a case study.--Introduction

The Arizona Range Cattle Market Report: An Experiment in Country-Sale Reporting

This item is part of the Agricultural Experiment Station archive. It was digitized from a physical copy provided by the University Libraries at the University of Arizona. For more information, please email CALS Publications at [email protected]

Preparation for meaningful work and life: urban high school youth's reflections on work-based learning 1 year post-graduation

The challenges confronted by low-income high school students throughout school and across the transition to higher education and employment are well-documented in the US and many other nations. Adopting a positive youth development perspective (Lerner et al., 2005), this study reports findings from interviews with 18 low-income, racially and ethnically diverse graduates of an urban Catholic high school in the US. The interviews were designed to shed light on the post-high school experiences of urban high school graduates and to understand how students construct meaning about the value of school and work-based learning (WBL) in their preparation for meaningful work and life. The interviews highlight the perceived value of the academic and non-cognitive preparation students experienced through high school and WBL in relation to the challenges they encountered along the pathway to post-high school success and decent work. Overall, the findings suggest the potential of WBL for low-income youth in facilitating access to resources that build academic and psychological/non-cognitive assets, while also illustrating the role of structural and contextual factors in shaping post-high school transitions and access to meaningful work and life opportunities.Published versio

Suppression of electron spin decoherence of the diamond NV center by a transverse magnetic field

We demonstrate that the spin decoherence of nitrogen vacancy (NV) centers in diamond can be suppressed by a transverse magnetic field if the electron spin bath is the primary decoherence source. The NV spin coherence, created in "a decoherence-free subspace" is protected by the transverse component of the zero-field splitting, increasing the spin-coherence time about twofold. The decoherence due to the electron spin bath is also suppressed at magnetic fields stronger than ~25 gauss when applied parallel to the NV symmetry axis. Our method can be used to extend the spin-coherence time of similar spin systems for applications in quantum computing, field sensing, and other metrologies.Comment: 20 pages, 4 figure

ADAD1 and ADAD2, testis-specific adenosine deaminase domain-containing proteins, are required for male fertility.

Adenosine-to-inosine RNA editing, a fundamental RNA modification, is regulated by adenosine deaminase (AD) domain containing proteins. Within the testis, RNA editing is catalyzed by ADARB1 and is regulated in a cell-type dependent manner. This study examined the role of two testis-specific AD domain proteins, ADAD1 and ADAD2, on testis RNA editing and male germ cell differentiation. ADAD1, previously shown to localize to round spermatids, and ADAD2 had distinct localization patterns with ADAD2 expressed predominantly in mid- to late-pachytene spermatocytes suggesting a role for both in meiotic and post-meiotic germ cell RNA editing. AD domain analysis showed the AD domain of both ADADs was likely catalytically inactive, similar to known negative regulators of RNA editing. To assess the impact of Adad mutation on male germ cell RNA editing, CRISPR-induced alleles of each were generated in mouse. Mutation of either Adad resulted in complete male sterility with Adad1 mutants displaying severe teratospermia and Adad2 mutant germ cells unable to progress beyond round spermatid. However, mutation of neither Adad1 nor Adad2 impacted RNA editing efficiency or site selection. Taken together, these results demonstrate ADAD1 and ADAD2 are essential regulators of male germ cell differentiation with molecular functions unrelated to A-to-I RNA editing