534 research outputs found

    Radiation effects in silicon solar cells Quarterly progress report, 1 Jul. - 30 Sep. 1970

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    Defects responsible for degradation in output of silicon solar cells irradiated by space radiatio

    Radiation effects in silicon solar cells Quarterly report

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    Effect of lithium on production and annealing of damage in silico

    Internal electrostatic discharge hazard risk assessment to the Galileo orbiter

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    A worst case assessment was performed on the Command Data System (CDS) multilayer printed circuit board and an output power transformer module in the power subsystem. An estimate of the Jovian environment during the 35 hour orbit insertion was supplied by JPL and used as an input to calculate the electron transport into the Galileo components. A radiation shielding analysis computer code, CHARGE, calculated the electron transport deposition trapped in the anticipated sensitive areas of the multilayer board and transformer module. Based on these trapped charge calculations electric fields were calculated between the identified isolated areas and the spacecraft ground. The results of the assessment of electrostatic discharge (DSD) in the CDS multilayer printed circuit board indicate that the probability of ESD in the FR4 is low. The probability of ESD in the components attached to the multilayer board, however, is uncertain based on a lack of prior experimental data

    Fire Protection Life Safety Analysis- Bachelor Enlisted Quarters

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    This Bachelor Enlisted Quarters (BEQ) shall be constructed, arranged, equipped, maintained, and operated in accordance with this report and applicable criteria to ensure a minimum level of life safety and property protection is provided from actual and potential fire hazards. The goal is to ensure the occupants are provided with an environment that is reasonably safe from fire. We accomplish this goal by protecting occupants not intimate with the initial fire development, and by improving the survivability of occupants intimate with the initial fire development. The protection described in this report takes on many forms, from active protection, such as fire protection systems, to passive protection, such as fire resistive construction. The applicable prescriptive-based design requirements outlined in the building and life safety codes are summarized, as well as a detailed description of the active fire protection systems provided in the BEQ. A performance-based analysis was utilized to evaluate the effectiveness of the prescriptive based requirements. Fire behavior predictions and fire protection response time estimates were compared to Computational Fluid Dynamic simulated results. The performance-based evaluation determined the required safe egress time (RSET) versus the available safe egress time (ASET). Based upon the results, the BEQ was designed and constructed to provide sufficient egress time to occupants prior to them being exposed to untenable conditions

    The genome of a pathogenic rhodococcus : cooptive virulence underpinned by key gene acquisitions

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    We report the genome of the facultative intracellular parasite Rhodococcus equi, the only animal pathogen within the biotechnologically important actinobacterial genus Rhodococcus. The 5.0-Mb R. equi 103S genome is significantly smaller than those of environmental rhodococci. This is due to genome expansion in nonpathogenic species, via a linear gain of paralogous genes and an accelerated genetic flux, rather than reductive evolution in R. equi. The 103S genome lacks the extensive catabolic and secondary metabolic complement of environmental rhodococci, and it displays unique adaptations for host colonization and competition in the short-chain fatty acid–rich intestine and manure of herbivores—two main R. equi reservoirs. Except for a few horizontally acquired (HGT) pathogenicity loci, including a cytoadhesive pilus determinant (rpl) and the virulence plasmid vap pathogenicity island (PAI) required for intramacrophage survival, most of the potential virulence-associated genes identified in R. equi are conserved in environmental rhodococci or have homologs in nonpathogenic Actinobacteria. This suggests a mechanism of virulence evolution based on the cooption of existing core actinobacterial traits, triggered by key host niche–adaptive HGT events. We tested this hypothesis by investigating R. equi virulence plasmid-chromosome crosstalk, by global transcription profiling and expression network analysis. Two chromosomal genes conserved in environmental rhodococci, encoding putative chorismate mutase and anthranilate synthase enzymes involved in aromatic amino acid biosynthesis, were strongly coregulated with vap PAI virulence genes and required for optimal proliferation in macrophages. The regulatory integration of chromosomal metabolic genes under the control of the HGT–acquired plasmid PAI is thus an important element in the cooptive virulence of R. equi

    Site-selective nuclear magnetic relaxation time in a superconducting vortex state

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    The temperature and field dependences of the site-selective nuclear spin relaxation time T_1 around vortices are studied comparatively both for s-wave and d-wave superconductors, based on the microscopic Bogoliubov-de Gennes theory. Reflecting low energy electronic excitations associated with the vortex core, the site selective temperature dependences deviate from those of the zero-field case, and T_1 becomes faster with approaching the vortex core. In the core region, T_1^{-1} has a new peak below the superconducting transition temperature T_c. The field dependence of the overall T_1(T) behaviors for s-wave and d-wave superconductors is investigated and analyzed in terms of the local density of states. The NMR study by the resonance field dependence may be a new method to probe the spatial resolved vortex core structure in various conventional and unconventional superconductors.Comment: 14Pages, 26 figures, revte

    Theory of vortex excitation imaging via an NMR relaxation measurement

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    The temperature dependence of the site-dependent nuclear spin relaxation time T_1 around vortices is studied in s-wave and d-wave superconductors.Reflecting low energy electronic excitations associated with the vortex core, temperature dependences deviate from those of the zero-field case, and T_1 becomes faster with approaching the vortex core. In the core region, T_1^{-1} has a new peak below T_c. The NMR study by the resonance field dependence may be a new method to prove the spatial resolved vortex core structure in various superconductors.Comment: 5 pages, 3 figure

    An archaeal family-B DNA polymerase variant able to replicate past DNA damage: occurrence of replicative and translesion synthesis polymerases within the B family

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    A mutant of the high fidelity family-B DNA polymerase from the archaeon Thermococcus gorgonarius (Tgo-Pol), able to replicate past DNA lesions, is described. Gain of function requires replacement of the three amino acid loop region in the fingers domain of Tgo-Pol with a longer version, found naturally in eukaryotic Pol zeta (a family-B translesion synthesis polymerase). Inactivation of the 3'–5' proofreading exonuclease activity is also necessary. The resulting Tgo-Pol Z1 variant is proficient at initiating replication from base mismatches and can read through damaged bases, such as abasic sites and thymine photo-dimers. Tgo-Pol Z1 is also proficient at extending from primers that terminate opposite aberrant bases. The fidelity of Tgo-Pol Z1 is reduced, with amarked tendency tomake changes at G:C base pairs. Together, these results suggest that the loop region of the fingers domain may play a critical role in determining whether a family-B enzyme falls into the accurate genome-replicating category or is an errorprone translesion synthesis polymerase. Tgo-Pol Z1 may also be useful for amplification of damaged DNA

    A Theory-Based Meta-Analysis: Stress Management Interventions for College Students

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    The purpose of this study was to determine the combined average effect size for the efficacy of stress management interventions in randomized controlled trials with college students. A workplace stress intervention approach guided article selection. A single instrument measured stress. The analysis was a random effects model. The literature search in the spring of 2020 yielded eight qualifying studies, published from 2014-2020. The overall effect size was statistically significant (g = ‒0.41). Especially given pandemic-related stressors, this meta-analysis could serve as a baseline for future research comparisons. It mirrored results of other meta-analyses, discussed in the literature review. No prior meta-analysis to our knowledge has employed the same approach or framework
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