Molecular Cloud Structure in the Magellanic Clouds: Effect of Metallicity

The chemical structure of neutral clouds in low metallicity environments is examined with particular emphasis on the H to H_2 and C+ to CO transitions. We observed near-IR H_2 lines and the CO J=1-0 line from 30 Doradus and N159/N160 in the Large Magellanic Cloud and from DEM S 16, DEM S 37, and LI-SMC 36 in the Small Magellanic Cloud. We find that the H_2 emission is UV-excited and that (weak) CO emission always exists (in our surveyed regions) toward positions where H_2 and [CII] emission have been detected. Using a PDR code and a radiative transfer code, we simulate the emission of line radiation from spherical clouds and from large planar clouds. Because the [CII] emission and H_2 emission arise on the surface of the cloud and the lines are optically thin, these lines are not affected by changes in the relative sizes of the neutral cloud and the CO bearing core, while the optically thick CO emission can be strongly affected. The sizes of clouds are estimated by measuring the deviation of CO emission strength from that predicted by a planar cloud model of a given size. The average cloud column density and therefore size increases as the metallicity decreases. Our result agrees with the photoionization regulated star formation theory by Mc Kee (1989).Comment: 45 Pages including 15 figures. To be published in the ApJ May 10, 1998 issue, Vol. 49

Quantum waveguides with a lateral semitransparent barrier: spectral and scattering properties

We consider a quantum particle in a waveguide which consists of an infinite straight Dirichlet strip divided by a thin semitransparent barrier on a line parallel to the walls which is modeled by a $\delta$ potential. We show that if the coupling strength of the latter is modified locally, i.e. it reaches the same asymptotic value in both directions along the line, there is always a bound state below the bottom of the essential spectrum provided the effective coupling function is attractive in the mean. The eigenvalues and eigenfunctions, as well as the scattering matrix for energies above the threshold, are found numerically by the mode-matching technique. In particular, we discuss the rate at which the ground-state energy emerges from the continuum and properties of the nodal lines. Finally, we investigate a system with a modified geometry: an infinite cylindrical surface threaded by a homogeneous magnetic field parallel to the cylinder axis. The motion on the cylinder is again constrained by a semitransparent barrier imposed on a ``seam'' parallel to the axis.Comment: a LaTeX source file with 12 figures (11 of them eps); to appear in J. Phys. A: Math. Gen. Figures 3, 5, 8, 9, 11 are given at 300 dpi; higher resolution originals are available from the author

Validity of the new lifestyles NL-1000 accelerometer for measuring time spent in moderate-to-vigorous physical activity in school settings

Current interest in promoting physical activity in the school environment necessitates an inexpensive, accurate method of measuring physical activity in such settings. Additionally, it is recognized that physical activity must be of at least moderate intensity in order to yield substantial health benefits. The purpose of the study, therefore, was to determine the validity of the New Lifestyles NL-1000 (New Lifestyles, Inc., Lee's Summit, Missouri, USA) accelerometer for measuring moderate-to-vigorous physical activity in school settings, using the Actigraph GT1M (ActiGraph, Pensacola, Florida, USA) as the criterion. Data were collected during a cross-country run (n = 12), physical education (n = 18), and classroom-based physical activities (n = 42). Significant and meaningful intraclass correlations between methods were found, and NL-1000 estimates of moderate-to-vigorous physical activity were not meaningfully different from GT1M-estimated moderate- to-vigorous physical activity. The NL-1000 therefore shows promising validity evidence as an inexpensive, convenient method of measuring moderate-to-vigorous physical activity in school settings

Generalized Phase Space Representation of Operators

Introducing asymmetry into the Weyl representation of operators leads to a variety of phase space representations and new symbols. Specific generalizations of the Husimi and the Glauber-Sudarshan symbols are explicitly derivedComment: latex, 8 pages, expanded version accepted by J. Phys.

Relinquishing and Governing the Volatile: The Many Afghanistans and Critical Research Agendas of NATO's Governance

This article invites academics and policy analysts to examine the mechanisms and legacy of NATO's security and development governance of Afghan social spaces by using critical theory concepts. It argues that such scholarly endeavors are growing in importance as the United States and NATO gradually pull their troops out of Afghanistan. Thus, the article suggests a broad twofold research agenda. First, it points out that researching social spaces such as towns, villages, marketplaces, and neighborhoods beyond the realm of intergovernmental politics can lead to thick descriptions of how such places have been governed from within by agents external to them. Second, the study argues for a multifaceted examination of instruments, strategies, and institutions of security governance, its conduct and social effects by deploying critical and Foucauldian concepts such as the rationality and apparatuses of power relations. Thereby, it proposes an inquiry into Provincial Reconstruction Teams and Afghan National Security Forces as spatially and temporally specific apparatuses of surveillance and security

Performance of Small Cluster Surveys and the Clustered LQAS Design to estimate Local-level Vaccination Coverage in Mali

<p>Abstract</p> <p>Background</p> <p>Estimation of vaccination coverage at the local level is essential to identify communities that may require additional support. Cluster surveys can be used in resource-poor settings, when population figures are inaccurate. To be feasible, cluster samples need to be small, without losing robustness of results. The clustered LQAS (CLQAS) approach has been proposed as an alternative, as smaller sample sizes are required.</p> <p>Methods</p> <p>We explored (i) the efficiency of cluster surveys of decreasing sample size through bootstrapping analysis and (ii) the performance of CLQAS under three alternative sampling plans to classify local VC, using data from a survey carried out in Mali after mass vaccination against meningococcal meningitis group A.</p> <p>Results</p> <p>VC estimates provided by a 10 × 15 cluster survey design were reasonably robust. We used them to classify health areas in three categories and guide mop-up activities: i) health areas not requiring supplemental activities; ii) health areas requiring additional vaccination; iii) health areas requiring further evaluation. As sample size decreased (from 10 × 15 to 10 × 3), standard error of VC and ICC estimates were increasingly unstable. Results of CLQAS simulations were not accurate for most health areas, with an overall risk of misclassification greater than 0.25 in one health area out of three. It was greater than 0.50 in one health area out of two under two of the three sampling plans.</p> <p>Conclusions</p> <p>Small sample cluster surveys (10 × 15) are acceptably robust for classification of VC at local level. We do not recommend the CLQAS method as currently formulated for evaluating vaccination programmes.</p

A model-based assessment of the effects of projected climate change on the water resources of Jordan

This paper is concerned with the quantification of the likely effect of anthropogenic climate change on the water resources of Jordan by the end of the twenty-first century. Specifically, a suite of hydrological models are used in conjunction with modelled outcomes from a regional climate model, HadRM3, and a weather generator to determine how future flows in the upper River Jordan and in the Wadi Faynan may change. The results indicate that groundwater will play an important role in the water security of the country as irrigation demands increase. Given future projections of reduced winter rainfall and increased near-surface air temperatures, the already low groundwater recharge will decrease further. Interestingly, the modelled discharge at the Wadi Faynan indicates that extreme flood flows will increase in magnitude, despite a decrease in the mean annual rainfall. Simulations projected no increase in flood magnitude in the upper River Jordan. Discussion focuses on the utility of the modelling framework, the problems of making quantitative forecasts and the implications of reduced water availability in Jordan

Religion and HIV in Tanzania: Influence of Religious Beliefs on HIV stigma, Disclosure, and Treatment Attitudes.

Religion shapes everyday beliefs and activities, but few studies have examined its associations with attitudes about HIV. This exploratory study in Tanzania probed associations between religious beliefs and HIV stigma, disclosure, and attitudes toward antiretroviral (ARV) treatment. A self-administered survey was distributed to a convenience sample of parishioners (n = 438) attending Catholic, Lutheran, and Pentecostal churches in both urban and rural areas. The survey included questions about religious beliefs, opinions about HIV, and knowledge and attitudes about ARVs. Multivariate logistic regression analysis was performed to assess how religion was associated with perceptions about HIV, HIV treatment, and people living with HIV/AIDS. Results indicate that shame-related HIV stigma is strongly associated with religious beliefs such as the belief that HIV is a punishment from God (p < 0.01) or that people living with HIV/AIDS (PLWHA) have not followed the Word of God (p < 0.001). Most participants (84.2%) said that they would disclose their HIV status to their pastor or congregation if they became infected. Although the majority of respondents (80.8%) believed that prayer could cure HIV, almost all (93.7%) said that they would begin ARV treatment if they became HIV-infected. The multivariate analysis found that respondents' hypothetical willingness to begin ARV treatme was not significantly associated with the belief that prayer could cure HIV or with other religious factors. Refusal of ARV treatment was instead correlated with lack of secondary schooling and lack of knowledge about ARVs. The decision to start ARVs hinged primarily on education-level and knowledge about ARVs rather than on religious factors. Research results highlight the influence of religious beliefs on HIV-related stigma and willingness to disclose, and should help to inform HIV-education outreach for religious groups