The analysis of a tragedy

This analysis shows the great importance of smoke barriers in isolating a fire in a large structure. The author is attempting to estimate mathematically fire growth and fire gas spread rate in the Beverly Hills Supper Club fire.     

MULTIPLE-SHIFT WORKFORCE SCHEDULING UNDER THE 3-4 COMPRESSED WORKWEEK WITH A HIERARCHICAL WORKFORCE

This paper provides efficient optimal workforce scheduling algorithms for 7-days-a-week operations, not necessarily 24 hours a day, under a compressed workweek arrangement called the 3-4 workweek. The model incorporates both the possibilities of shift rotation and downward worker substitutability. The model is readily usable in many 7-days-a-week operations (e.g., hospitals and utilities).     

Expression of the smooth-muscle proteins alpha-smooth-muscle actin and calponin, and of the intermediate filament protein desmin are parameters of cardiomyocyte maturation in the prenatal rat heart

Tip growth of plant cells has been suggested to be regulated by a tip-focused gradient in cytosolic calcium concentration ([Ca2+]c). However, whether this gradient orients apical growth or follows the driving force for this process remains unknown. Using localized photoactivation of the caged calcium ionophore Br-A23187 we have been able to artificially generate an asymmetrical calcium influx across the root hair tip. This led to a change in the direction of tip growth towards the high point of the new [Ca2+]c gradient. Such reorientation of growth was transient and there was a return to the original direction within 15 min. Root hairs forced to change the direction of their growth by placing a mechanical obstacle in their path stopped, reoriented growth to the side, and grew past the mechanical blockage. However, as soon as the growing tip had cleared the obstacle, growth returned to the original direction. Confocal ratio imaging revealed that a tip-focused [Ca2+]c gradient was always centered at the site of active growth. When the root hair changed direction the gradient also reoriented, and when growth returned to the original direction, so did the [Ca2+]c gradient. This normal direction of apical growth of Arabidopsis thaliana (L.) Heynh, root hairs was found to be at a fixed angle from the root of 85 +/- 6.7 degrees. In contrast, Tradescantia virginiana (L.) pollen tubes that were induced to reorient by touch or localized activation of the caged ionophore, did not return to the original growth direction, but continued to elongate in their new orientation. These results suggest that the tip-focused [Ca2+]c gradient is an important factor in localizing growth of the elongating root hair and pollen tube to the apex. However, it is not the primary determinant of the direction of elongation in root hairs, suggesting that other information from the root is acting to continuously reset the growth direction away from the root surface.     

Cutaneous reactions following herpes zoster infections: report of three cases and a review of the literature

Three patients, one healthy and two immunocompromised, developed cutaneous reactions that histologically mimicked granuloma annulare at sites of resolved varicella-zoster virus (VZV) reactivation infections. Variable latency periods between the infection and the granulomatous reaction were noted. As in other case reports, the presence of VZV DNA in these lesions was inconsistently demonstrated by the polymerase chain reaction (PCR) and appears more common in early, as opposed to late, post-zoster granulomas. In addition to various granulomatous reactions, vasculitic and neoplastic eruptions following resolved VZV infections have been described and are reviewed here. Therapeutically, topical, intralesional and systemic corticosteroids, as well as acyclovir, have been tried with inconsistent results. Although the pathogenesis remains unclear, the presence of VZV DNA in early lesions that histologically do not display viral cytopathic changes, suggests the virus induces an atypical delayed hypersensitivity reaction not affected by antiviral therapy.     

1997 American Urological Association Gallup survey: Changes in diagnosis and management of prostate cancer and benign prostatic hyperplasia, and other practice trends from 1994 to 1997

PURPOSE: The American Urological Association first commissioned the Gallup Organization to conduct a study to assess urologist practice patterns in 1992. We present the results of the 1997 survey, the sixth consecutive Gallup survey performed for the Association. MATERIALS AND METHODS: A random sample of 502 American urologists who had completed urological residency and practiced at least 20 hours weekly in 1996 was interviewed by telephone in February and March 1997. RESULTS: Emerging trends showed significant changes since 1994 in how urologists diagnosed and treated prostate cancer. The survey revealed a significant change in the tests routinely ordered to stage newly diagnosed prostate cancer and for diagnostic evaluation of patients with benign prostatic hyperplasia. CONCLUSIONS: Urologists are becoming more cost conscious and effective in ordering pretreatment testing. Urologists are becoming more oriented toward medical treatment for the management of benign prostatic hyperplasia, and less laser surgery is being performed.