Computer aided control and display system familiarization manual

Computerized control and display system for Apollo communication syste

Properties of cryogenically worked materials Final report

Steel and cobalt-nickel alloy compression and corrosion tests after precipitation hardening at cryogenic temperatures for increased yield strength and corrosion resistanc

Normalized Ricci flow on Riemann surfaces and determinants of Laplacian

In this note we give a simple proof of the fact that the determinant of Laplace operator in smooth metric over compact Riemann surfaces of arbitrary genus $g$ monotonously grows under the normalized Ricci flow. Together with results of Hamilton that under the action of the normalized Ricci flow the smooth metric tends asymptotically to metric of constant curvature for $g\geq 1$, this leads to a simple proof of Osgood-Phillips-Sarnak theorem stating that that within the class of smooth metrics with fixed conformal class and fixed volume the determinant of Laplace operator is maximal on metric of constant curvatute.Comment: a reference to paper math.DG/9904048 by W.Mueller and K.Wendland where the main theorem of this paper was proved a few years earlier is adde

Properties of cryogenically worked materials Interim report

Cryogenically worked materials during strain hardenin

Social Disorganization Outside the Metropolis: An Analysis of Rural Youth Violence

In order to extend the study of community social disorganization and crime beyond its exclusive focus on large urban centers, we present an analysis of structural correlates of arrest rates for juvenile violence in 264 nonmetropolitan counties of four states. Findings support the generality of social disorganization theory: Juvenile violence was associated with rates of residential instability, family disruption, and ethnic heterogeneity. Though rates of poverty were not related to juvenile violence, this is also in accord with social disorganization theory because, unlike urban settings, poverty was negatively related to residential instability. Rates of juvenile violence varied markedly with population size through a curvilinear relationship in which counties with the smallest juvenile populations had exceptionally low arrest rates. Analyses used negative binomial regression (a variation of Poisson regression) because the small number of arrests in many counties meant that arrest rates would be ill suited to least-squares regression

Current crisis or artifact of surveillance: insights into rebound chlamydia rates from dynamic modelling

<p>Abstract</p> <p>Background</p> <p>After initially falling in the face of intensified control efforts, reported rates of sexually transmitted chlamydia in many developed countries are rising. Recent hypotheses for this phenomenon have broadly focused on improved case finding or an increase in the prevalence. Because of many complex interactions behind the spread of infectious diseases, dynamic models of infection transmission are an effective means to guide learning, and assess quantitative conjectures of epidemiological processes. The objective of this paper is to bring a unique and robust perspective to observed chlamydial patterns through analyzing surveillance data with mathematical models of infection transmission.</p> <p>Methods</p> <p>This study integrated 25-year testing volume data from the Canadian province of Saskatchewan with one susceptible-infected-treated-susceptible and three susceptible-infected-treated-removed compartmental models. Calibration of model parameters to fit observed 25-year case notification data, after being combined with testing records, placed constraints on model behaviour and allowed for an approximation of chlamydia prevalence to be estimated. Model predictions were compared to observed case notification trends, and extensive sensitivity analyses were performed to confirm the robustness of model results.</p> <p>Results</p> <p>Model predictions accurately mirrored historic chlamydial trends including an observed rebound in the mid 1990s. For all models examined, the results repeatedly highlighted that increased testing volumes, rather than changes in the sensitivity and specificity of testing technologies, sexual behaviour, or truncated immunological responses brought about by treatment can, explain the increase in observed chlamydia case notifications.</p> <p>Conclusions</p> <p>Our results highlight the significant impact testing volume can have on observed incidence rates, and that simple explanations for these observed increases appear to have been dismissed in favor of changes to the underlying prevalence. These simple methods not only demonstrate geographic portability, but the results reassure the public health effort towards monitoring and controlling chlamydia.</p

Community Correlates of Rural Youth Violence

Rates of crime and delinquency vary widely across communities, and research going back many decades provides a good understanding of the nature, correlates, and probable causes of these community differences. Unfortunately, previous studies have been limited in an important way. Virtually all studies of communities and crime are based on large urban areas, almost totally excluding nonmetropolitan areas—that is, rural areas and smaller cities and towns. The findings in this Bulletin help to fill some gaps in the research by examining variations in rates of juvenile violence across nonmetropolitan communities in Florida, Georgia, Nebraska, and South Carolina. Social disorganization is the primary theory by which criminologists account for rates of crime in urban communities. If this theory also applies to rural settings, then what is known about crime in urban areas can provide a basis for developing programs that address the problem of delinquency in smaller communities. The research presented in this Bulletin indicates that the principles of social disorganization theory hold up quite well in rural settings. As in urban areas, rates of juvenile violence are considerably higher in rural communities that have a large percentage of children living in single-parent households, a high rate of population turnover, and significant ethnic diversity. These factors, it should be noted, are statistical correlates and not causes of such violence; nor are they the only correlates