Feasibility model of a high reliability five-year tape transport, volume 2

Analysis of the design features of the modularized tape transport renders a life expectancy in excess of five years. Tests performed on the tape transport were directed toward determining its performance capability. These tests revealed that the tape jitter and skew are in the range achieved by high quality digital tape transports. Guidance of the tape in the lateral sense by the use of the two hybrid crowned rollers proved to be excellent. Tracking was maintained within less than one thousandth inch (approximately 2 micrometers). The guidance capability demonstrated makes possible the achievement of the performance objective of 7.2 x 10 to the 9th power storage capability employing 1500 ft. of one inch wide tape with a packing density of 5,000 bits per inch per track on 80 tracks. Also, the machine showed excellent characteristics operating over a wide range of tape speeds. The basic design concept lends itself to growth and adaptation to a wide range of recorder requirements

Feasibility model of a high reliability five-year tape transport, Volume 1

The development, performance, and test results for the spaceborne magnetic tape transport are discussed. An analytical model of the tape transport was used to optimize its conceptual design. Each of the subsystems was subjected to reliability analyses which included structural integrity, maintenance of system performance within acceptable bounds, and avoidance of fatigue failure. These subsystems were also compared with each other in order to evaluate reliability characteristics. The transport uses no mechanical couplings. Four drive motors, one for each reel and one for each of two capstans, are used in a differential mode. There are two hybrid, spherical, cone tapered-crown rollers for tape guidance. Storage of the magnetic tape is provided by a reel assembly which includes the reel, a reel support structure and bearings, dust seals, and a dc drive motor. A summary of transport test results on tape guidance, flutter, and skew is provided

Internships: The Nuts And Bolts Of An Effective Program

Braxston Public Engineering and Consulting Group (BPECG) is a nationally known and respected company that is magnate for students who wish to receive a valued internship experience.   Under the able direction of Amy Greene, the work experiences were coordinated during the summer and interns were well paid for their contributions.  The case study chronicles the trials and tribulations faced by a competent, highly energized engineering intern who faces the malaise of an organization that is unprepared to provide a valid learning experience. As the case unfolds, Greene has an Eureka experience and learns from a colleague how interns can and do make vital contributions (ROI’s) to their assigned organizations. Upon reviewing the contributions that interns made in three organizations, she redesigns Braxston’s Internship program, reviews the State University Intern to Work Program that addresses, among many other factors, the internship purpose, supervision, learning objectives,  and intern and employer obligations.  The case includes an Intern Evaluation form and a Memorandum of Understanding (MOU) between the university and the company. Last, the Questions and Instructions provide for focused discussion and analysis and the references enable learners to research the top internship programs in the United States

Children's construction task performance and spatial ability: controlling task complexity and predicting mathematics performance.

This paper presents a methodology to control construction task complexity and examined the relationships between construction performance and spatial and mathematical abilities in children. The study included three groups of children (N = 96); ages 7-8, 10-11, and 13-14 years. Each group constructed seven pre-specified objects. The study replicated and extended previous findings that indicated that the extent of component symmetry and variety, and the number of components for each object and available for selection, significantly predicted construction task difficulty. Results showed that this methodology is a valid and reliable technique for assessing and predicting construction play task difficulty. Furthermore, construction play performance predicted mathematical attainment independently of spatial ability

Supporting the Employment of Mothers: Policy Variation Across Fourteen Welfare States

Despite their broadly similar political and economic systems, the rates and patterns of mothers\u27 employment vary considerably across industrialized countries. This variation raises questions about the role played by government policies in enabling mothers to choose employment and, in turn, in shaping both gender equality and family economic well-being. This paper compares fourteen OECD countries, as of the middle-to-late 1980s, with respect to their provision of policies that support mothers\u27 employment: parental leave, child care, and the scheduling of public education. Newly gathered data on eighteen policy indicators are presented; these indicators were chosen to capture support for maternal employment, regardless of national intent. The indicators are then standardized, weighted, and summed into indices. By differentiating policies that affect maternal employment from family policies more generally, while simultaneously aggregating individual policies and policy features into policy packages , these indices reveal dramatic cross-national differences in policy provisions. The empirical results reveal loose clusters of countries that correspond only partially to prevailing welfare state typologies. For mothers with preschool-aged children, only five of the fourteen countries provided reasonably complete and continuous benefits that supported their options for combining paid work with family responsibilities. In the remaining countries, government provisions were much more limited or discontinuous. The pattern of cross-national policy variation changed notably when policies affecting mothers with older children were examined. The links between these findings and three sets of outcomes are considered. The indices provide an improved measure of public support for maternal employment and are expected to help explain cross-national differences in the level and continuity of women\u27s labor market attachment. Prior findings on women\u27s labor supply provide initial support for this conclusion. These indices are also useful for contrasting family benefits that are provided through direct cash transfers with those that take the form of support for mothers\u27 employment. Cross-national variation in combinations of transfers with employment supports is found to correspond to differences in child poverty rates. Finally, these policy findings contribute to the body of scholarship that seeks to integrate gender issues more explicitly into research on welfare state regimes. This study suggests that the country clusters identified in the dominant regime model fail to cohere with respect to the subset of family policies that specifically help women to combine paid work with parenting

Plants regenerated from tissue culture contain stable epigenome changes in rice.

Most transgenic crops are produced through tissue culture. The impact of utilizing such methods on the plant epigenome is poorly understood. Here we generated whole-genome, single-nucleotide resolution maps of DNA methylation in several regenerated rice lines. We found that all tested regenerated plants had significant losses of methylation compared to non-regenerated plants. Loss of methylation was largely stable across generations, and certain sites in the genome were particularly susceptible to loss of methylation. Loss of methylation at promoters was associated with deregulated expression of protein-coding genes. Analyses of callus and untransformed plants regenerated from callus indicated that loss of methylation is stochastically induced at the tissue culture step. These changes in methylation may explain a component of somaclonal variation, a phenomenon in which plants derived from tissue culture manifest phenotypic variability. DOI:http://dx.doi.org/10.7554/eLife.00354.001

Drug resistance mutations among antiretroviral-treated female sex workers in Nairobi, Kenya

Antiretroviral drug resistance remains an important and a growing challenge in HIV management as it almost always lead to treatment failure. Sex workers face persistent exposures to the different HIV-1 variants and in turn pose a risk of transmission to the general population and measuring drug resistance in this population may serve as a measure for the risk of transmission of these strains to drug naïve populations. The objective of this study was therefore to determine the pattern and prevalence of HIV-1 drug resistance mutations in a cohort of female sex workers in Nairobi, Kenya. Plasma from 60 female sex workers on antiretroviral treatment for over six months was analyzed by amplification and sequencing of the reverse transcriptase - pol region. Five samples (8.3%) showed antiretroviral resistance-associated mutations. One sample (1.7%) showed mutations conferring resistance only to the NNRTI class, 2 samples (3.3%) showed mutations conferring resistance only to the NRTI class while 2 samples (3.3%) showed mutations conferring resistance to both NRTI and NNRTI classes. Phylogenetic analysis revealed HIV-1 subtype A1 (96.7%) and HIV-1 subtype D (3.3%). The prevalence rate of 8.3% for reverse transcriptase-associated resistance mutations was observed. This is a lower rate than has been reported from studies among antiretroviral (ARV)-treated individuals in the country.Afr J Health Sci. 2013; 26:291-30