Silvabase: A flexible data file management system

The need for a more flexible and efficient data file management system for mission planning in the Mission Operations Laboratory (EO) at MSFC has spawned the development of Silvabase. Silvabase is a new data file structure based on a B+ tree data structure. This data organization allows for efficient forward and backward sequential reads, random searches, and appends to existing data. It also provides random insertions and deletions with reasonable efficiency, utilization of storage space well but not at the expense of speed, and performance of these functions on a large volume of data. Mission planners required that some data be keyed and manipulated in ways not found in a commercial product. Mission planning software is currently being converted to use Silvabase in the Spacelab and Space Station Mission Planning Systems. Silvabase runs on a Digital Equipment Corporation's popular VAX/VMS computers in VAX Fortran. Silvabase has unique features involving time histories and intervals such as in operations research. Because of its flexibility and unique capabilities, Silvabase could be used in almost any government or commercial application that requires efficient reads, searches, and appends in medium to large amounts of almost any kind of data

Smoking and Mortality Among US Astronauts

Astronauts have lower age-specific mortality risk than the U.S. general population from all natural causes of death, particularly cardiovascular disease and cancer. Yet, understanding if they are as healthy as their backgrounds predict they should be, requires that epidemiologists understand (and measure) all potentially confounding exposures in this cohort. Tobacco smoking prevalence has been measured in the U.S. astronaut cohort, but its impact on mortality has not been previously assessed. If smoking history has a negative impact on mortality, this could confound attempts to measure the relative health of astronauts

Simulations of MHD Instabilities in Intracluster Medium Including Anisotropic Thermal Conduction

We perform a suite of simulations of cooling cores in clusters of galaxies in order to investigate the effect of the recently discovered heat flux buoyancy instability (HBI) on the evolution of cores. Our models follow the 3-dimensional magnetohydrodynamics (MHD) of cooling cluster cores and capture the effects of anisotropic heat conduction along the lines of magnetic field, but do not account for the cosmological setting of clusters or the presence of AGN. Our model clusters can be divided into three groups according to their final thermodynamical state: catastrophically collapsing cores, isothermal cores, and an intermediate group whose final state is determined by the initial configuration of magnetic field. Modeled cores that are reminiscent of real cluster cores show evolution towards thermal collapse on a time scale which is prolonged by a factor of ~2-10 compared with the zero-conduction cases. The principal effect of the HBI is to re-orient field lines to be perpendicular to the temperature gradient. Once the field has been wrapped up onto spherical surfaces surrounding the core, the core is insulated from further conductive heating (with the effective thermal conduction suppressed to less than 1/100th of the Spitzer value) and proceeds to collapse. We speculate that, in real clusters, the central AGN and possibly mergers play the role of "stirrers," periodically disrupting the azimuthal field structure and allowing thermal conduction to sporadically heat the core.Comment: 16 pages, 3 tables, 17 figures, accepted to ApJ with minor revisions, to appear in Volume 704, Oct 20, 2009 issu

Mortality of major league baseball players from Canada, Latin America, and the Caribbean

Professional baseball players have lower mortality rates than the US general population, but whether this is true of foreign-born players is not known. Using data on ballplayers from six nations, we compare mortality rates with those of US players via standardized mortality ratios. After controlling for confounders, four countries had statistically insignificant SMRs while two nations had significantly elevated SMRs. In the two nations with elevated SMRs, low average ages at death and high crime rates suggest the increased mortality may be linked to violent crime. A full understanding of the causes of disparity in mortality will require further research

The Mortality of Space Explorers

Outer space exploration poses unique risks to human survival. Here, we review the current literature on United States astronauts and Soviet and Russian cosmonauts and provide updated and original research findings. As in previous research, both astronauts and cosmonauts are shown to have reduced risk of death by natural causes, particularly from chronic diseases such as cardiovascular disease and cancer, compared with appropriately matched general populations. Simultaneously, space explorers are at increased risk of death by external forces, particularly accidents such as plane crashes and spacecraft accidents. In total, both astronauts and cosmonauts are at reduced risk of all-cause mortality in comparison to the general populations of the United States and Russia. However, in comparison to astronauts, cosmonauts have been at equal risk of accidental death, but increased risk of death by chronic disease. We conjecture that the lack of risk from chronic disease may be due to the excellent health and medical monitoring of space explorers coupled with the deliberate attempts to limit their radiation exposure levels below those that would be detrimental. The differences in the astronaut and cosmonaut mortality experiences are likely due to lifestyle factors and the background rates of mortality in the two nations

Survival, Mortality, and Life Expectancy

Cerebral palsy (CP) is a heterogenous condition, with level of disability ranging from immaterial to profound. In concert with the continuum of level of severity of disability/independent functioning, health care needs, therapies, medications, surgical interventions, costs of care, daily demands on parents and other family members, and expectations for the future in terms of education, employment, and other milestones of life all vary widely. Similarly, life expectancy in CP follows a continuum, from far lower than to potentially as high as general population life expectancy, that parallels the continuum of levels of disability. Here we review the literature documenting this, and examine the specific factors that are known to be strongly associated with mortality and longevity in CP. We also examine the evidence regarding causes of death in CP, and present some new findings related to this. Finally, we outline important methodological considerations for future research in this area

Who Ya Gonna Call? Networks of Rural School Administrators

When they need help or advice, who are rural school administrators going to call? Relationships among rural school administrators develop into networks that can affect the success of administrators and their schools. Understanding the structure and content of these networks provides insights into how resources, innovations, and communication flow both within and between rural district administrators. Based on network theory and analysis, this study examines the structure, content, and strategic implications of the administrative networks within and across six contiguous rural school districts in the Western United States. Network graphs are included, illustrating both individual district and the combined six-district rural administrator networks. While acquaintance ties and active work ties are evident both within and across districts, relationally embedded ties and greater cohesion of ties are more evident within districts than across districts. Analyses include consideration of administrative assignment, gender, and geographical location of the network structures. Strategic implications of the network structures and content are discussed

A Quality Management Approach to Implementing Point-of-Care Technologies for HIV Diagnosis and Monitoring in Sub-Saharan Africa

Technology advances in rapid diagnosis and clinical monitoring of human immunodeficiency virus (HIV) infection have been made in recent years, greatly benefiting those at risk of HIV infection, those needing care and treatment, and those on antiretroviral (ART) therapy in sub-Saharan Africa. However, resource-limited, geographically remote, and harsh climate regions lack uniform access to these technologies. HIV rapid diagnostic tests (RDTs) and monitoring tools, such as those for CD4 counts, as well as tests for coinfections, are being developed and have great promise in these settings to aid in patient care. Here we explore the advances in point-of-care (POC) technology in the era where portable devices are bringing the laboratory to the patient. Quality management approaches will be imperative for the successful implementation of POC testing in endemic settings to improve patient care

Guidelines for Integrating Deer and Timber Management in northern New York

To research selected aspects of deer resource dynamics that have been identified as key components in the redefinition and/or implementation of deer management strategic plans and programs in northern New York

Eggshell pigment composition covaries with phylogeny but not with life history or with nesting ecology traits of British passerines

No single hypothesis is likely to explain the diversity in eggshell coloration and patterning across birds, suggesting that eggshell appearance is most likely to have evolved to fulfill many nonexclusive functions. By controlling for nonindependent phylogenetic associations between related species, we describe this diversity using museum eggshells of 71 British breeding passerine species to examine how eggshell pigment composition and concentrations vary with phylogeny and with life-history and nesting ecology traits. Across species, concentrations of biliverdin and protoporphyrin, the two main pigments found in eggshells, were strongly and positively correlated, and both pigments strongly covaried with phylogenetic relatedness. Controlling for phylogeny, cavity-nesting species laid eggs with lower protoporphyrin concentrations in the shell, while higher biliverdin concentrations were associated with thicker eggshells for species of all nest types. Overall, these relationships between eggshell pigment concentrations and the biology of passerines are similar to those previously found in nonpasserine eggs, and imply that phylogenetic dependence must be considered across the class in further explanations of the functional significance of avian eggshell coloration