Combining ray-trace and diffraction analysis: A design example

An example is presented of using a combined ray trace and diffraction modeling code to simulate effects of objective-lens tilt in an optical data storage device. In some cases, neither ray-trace analysis nor diffraction analysis can give an adequate description of an optical system. The designer that is faced with the problem of analyzing such a system is forced to use a ray-trace program to determine aberrations in the exit pupil and then introduce aberration coefficients into a diffraction model that simulate the propagation. This approach was found rather awkward, especially if complicated aberrations are present. Our approach is to integrate a diffraction analysis and a ray-trace description of an optical path into one program. Our design is taken from a data storage application, where we must analyze the effects of objective-lens tilt

Complementary Algorithms For Tableaux

We study four operations defined on pairs of tableaux. Algorithms for the first three involve the familiar procedures of jeu de taquin, row insertion, and column insertion. The fourth operation, hopscotch, is new, although specialised versions have appeared previously. Like the other three operations, this new operation may be computed with a set of local rules in a growth diagram, and it preserves Knuth equivalence class. Each of these four operations gives rise to an a priori distinct theory of dual equivalence. We show that these four theories coincide. The four operations are linked via the involutive tableau operations of complementation and conjugation.Comment: 29 pages, 52 .eps files for figures, JCTA, to appea

A Study of Persistence in the Walters State Community College Associate-Degree Nursing Program.

The WSCC ADN program had 66.57% persistence rate between the years 2000-2004. This retrospective study analyzed 28 demographic, pre-clinical, and clinical variables to identify correlates for persistence within the WSCC ADN program. The population size was 730 first-time candidates or the entire population of five consecutive clinical classes graduating between the years of 2000-2004. The candidates were identified and the variables tabulated using the WSCC student information system. SPSS 13.0 software was employed to conduct descriptive, frequency, multiple regression, multivariate analysis of variance, and univariate analysis of variance tests. The criterion variables included persistence within the entire population, gender-specific persistence factors, and age-specific factors within the traditional and non-traditional populations that persisted. Descriptive and frequency analysis found that most candidates were female (90.82%), Caucasian (96.44%), and classified as non-traditional (63.97%). Females and particularly non-traditional females maintained the highest persistence rates. The mean pre-clinical and clinical admittance ages were 25.04 and 28.39 years. Seventy percent of the candidates lived within the WSCC service area. The mean distance commuted was 37.71 miles. Statistical tests revealed that nine predictor variables influenced persistence within the entire population. The largest contributors of variance were 2nd semester clinical GPA (η2 = .33), cumulative pre-clinical GPA (η2 = .15), and grades in microbiology (η2 = .14). These variables along with the number of course withdrawals and/or grades of “F” were found to be major indicators for persistence within the female and male sub-populations. The number of full-time semesters was a more significant contributor in the male population (η2 = .12) than the female population (η2 = .02). Data analysis revealed that non-traditional students who persisted had higher human anatomy and physiology II grades while the traditional students had a higher rate of transferring coursework into the nursing program. These findings will aid in the direction of the recruitment, evaluation, and selection of potential candidates for this very demanding program of study while validating the importance of prerequisite core knowledge. The findings should serve as predictive evidence to better identify and inform potential “at-risk” candidates of the factors that affect persistence in this nursing program

Dynamical Expansion of H II Regions from Ultracompact to Compact Sizes in Turbulent, Self-Gravitating Molecular Clouds

The nature of ultracompact H II regions (UCHRs) remains poorly determined. In particular, they are about an order of magnitude more common than would be expected if they formed around young massive stars and lasted for one dynamical time, around 10^4 yr. We here perform three-dimensional numerical simulations of the expansion of an H II region into self-gravitating, radiatively cooled gas, both with and without supersonic turbulent flows. In the laminar case, we find that H II region expansion in a collapsing core produces nearly spherical shells, even if the ionizing source is off-center in the core. This agrees with analytic models of blast waves in power-law media. In the turbulent case, we find that the H II region does not disrupt the central collapsing region, but rather sweeps up a shell of gas in which further collapse occurs. Although this does not constitute triggering, as the swept-up gas would eventually have collapsed anyway, it does expose the collapsing regions to ionizing radiation. We suggest that these regions of secondary collapse, which will not all themselves form massive stars, may form the bulk of observed UCHRs. As the larger shell will take over 10^5 years to complete its evolution, this could solve the timescale problem. Our suggestion is supported by the ubiquitous observation of more diffuse emission surrounding UCHRs.Comment: accepted to ApJ, 40 pages, 13 b/w figures, changes from v1 include analytic prediction of radio luminosity, better description of code testing, and many minor changes also in response to refere

Legal Socialization of Children and Adolescents

Research on children and the law has recently renewed its focus on the development of children\u27s ties to law and legal actors. We identify the developmental process through which these relations develop as legal socialization, a process that unfolds during childhood and adolescence as part of a vector of developmental capital that promotes compliance with the law and cooperation with legal actors. In this paper, we show that ties to the law and perceptions of law and legal actors among children and adolescents change over time and age. We show that neighborhood contexts and experiences with legal actors shape the outcomes of legal socialization. Children report lower ratings of legitimacy of the law and greater legal cynicism when they view interactions with legal actors as unfair and harsh. We show that perceived legitimacy of law and legal authorities shapes compliance with the law, and that these effects covary with social contexts including neighborhood. We identify neighborhood differences in this relationship that reflect differential experiences of children with criminal justice authorities and other social control agents. The results suggest that legal actors may play a role in socialization processes that lead to compliance with or rejection of legal and social norms

First Report of the Neoephemeridae (Ephemeroptera) in Wisconsin

The mayfly family Neoephemeridae was discovered in Wisconsin for the first time and is represented by the species Neoephemera bicolor. Nymphs were collected from three sites in two rivers in northern Wisconsin. Adults were reared from nymphs. Some physical and chemical characteristics of the sample locations are discussed