Airborne radon concentration was monitored in the basement of one house during the six-day investigation and was seen to increase substantially each of the seven occasions that the house was depressurized.The techniques employed are applicable to the study of problems of excessive radon entry into buildings and the migration of toxic chemicals from waste dumps and landfills.

No abstract

Simulations of droplet train impingement on a pre-wetted solid surface heated from below are used to study the thermal boundary layer behavior over a parameter space which includes variations in Reynolds, Peclet, and Weber numbers, as well as variations in inter-droplet spacing and initial liquid film thickness. Computationally, a modified version of the Volume-of-Fluid method is developed and employed in this study. The solver is validated against closed form solutions and additional experimental data from the literature. In combination with the simulations, an analytical representation is also developed and compared to the computations yielding favorable agreement. Results show that the boundary layer thickness is mostly affected by changes in inter-droplet spacing, Reynolds, and Peclet number, and influenced minimally by variations in Weber number and initial film thickness. In fact, it is explicitly demonstrated in the analysis that the impact velocity has the greatest effect in local heat transfer. An analytical expression for the Nusselt number radial profile is also developed. It shows that the Nusselt number scales as ∼ Re1/2, and its radial dependence is \documentclass[12pt]{minimal}\begin{document}$\sim \sqrt{r}$\end{document}∼r, which is the same as the circular jet impingement case. The notable difference in the present Nusselt number relationship is the role of inter-droplet spacing, which plays a significant role in the current configuration.

No abstract

Many studies in the genus Poecilia have focused on reproductive and genetic characteristics of Poecilia formosa, the Amazon molly, and its sympatric species P. latipinna and P. mexicana. The research literature of Poecilia dentition has been limited to general tooth morphology. Essentially absent are comparative analyses of dentition patterns and total numbers of teeth. The current study uses dentition analysis as a method to compare species in the genus Poecilia and to address some taxonomic issues related to these fish. The study focused on fish from the areas of southern Texas and northeastern Mexico. Through the use of scanning electron microscopy, the lower jaws of Poecilia spp were examined to determine total numbers of outer and inner teeth. In addition, the differences in distribution patterns of the inner teeth were recorded and compared. Statistical analyses were performed to determine which comparisons were significant. This study reveals several observations: 1) variations in the numbers of outer and inner teeth exist in some of these fish with respect to site of collection; 2) differences in total teeth numbers and dentition patterns were found both interspecifically and intraspecifically; and 3) in addition, dentition analysis provided evidence regarding the origin of P. formosa. This study supports the current notion that P. latipinna, the proported paternal component, and P. mexicana limantouri, the purported maternal component, are the progenitor species of P. formosa. Two unresolved taxonomic questions were addressed through dentition analysis. First, the present study supports the exclusion of the triploid associate of P. formosa as a separate species from P. formosa. Second, this study shows a significant difference in the number of inner teeth and in dentition patterns between P. mexicana limantouri and P. mexicana mexicana. Such differences, in addition to previously known distinguishing characteristics, should prompt careful consideration of whether or not these taxa deserve specific status or retention of their current subspecific status. J. Morphol. 239:271–282, 1999. © 1999 Wiley‐Liss, Inc.

No abstract

Clerkships are defining experiences for medical students in which students integrate basic science knowledge with clinical information as they gain experience in diagnosing and treating patients in a variety of clinical settings. Among the basic sciences, there is broad agreement that anatomy is foundational for medical practice. Unfortunately, there are longstanding concerns that student knowledge of anatomy is below the expectations of clerkship directors and clinical faculty. Most allopathic medical schools require eight “core” clerkships: internal medicine (IM), pediatrics (PD), general surgery (GS), obstetrics and gynecology (OB), psychiatry (PS), family medicine (FM), neurology (NU), and emergency medicine (EM). A targeted needs assessment was conducted to determine the anatomy considered important for each core clerkship based on the perspective of clinicians teaching in those clerkships. A total of 525 clinical faculty were surveyed at 24 United States allopathic medical schools. Participants rated 97 anatomical structure groups across all body regions on a 1–4 Likert‐type scale (1 = not important, 4 = essential). Non‐parametric ANOVAs determined if differences existed between clerkships. Combining all responses, 91% of anatomical structure groups were classified as essential or more important. Clinicians in FM, EM, and GS rated anatomical structures in most body regions significantly higher than at least one other clerkship (p = 0.006). This study provides an evidence‐base of anatomy content that should be considered important for each core clerkship and may assist in the development and/or revision of preclinical curricula to support the clinical training of medical students.

No abstract