Analysis of transient, linear wave propagation in shells by the finite difference method

The applicability of the finite difference method to propagation problems in shells, and the response of a cylindrical shell with cutouts to both longitudinal and radial transient excitations are investigated. It is found that the only inherent limitation of the finite difference method is its inability to reproduce accurately response discontinuities. The short wave length limitations of thin shell theory create significant convergence difficulties may often be overcome through proper selection of finite difference mesh dimensions and temporal or spatial smoothing of the excitation. Cutouts produce moderate changes in early and intermediate time response of a cylindrical shell to axisymmetric pulse loads applied at one end. The cutouts may facilitate the undesirable late-time transfer of load-injected extensional energy into nonaxisymmetric flexural response

Localness in climate change

Climate change is a global problem, yet it is experienced at the local scale, in ways that are both place-specific and specific to the accidents of weather history. This article takes the dichotomy between the global and the local as a starting point to develop a critique of the normative approach within climate science, which is global in various ways and thereby fails to bring meaning to the local. The article discusses the ethical choices implicit in the current paradigm of climate prediction, how irreducible uncertainty at the local scale can be managed by suitable reframing of the scientific questions, and some particular epistemic considerations that apply to climate change in the global South. The article argues for an elevation of the narrative and for a demotion of the probabilistic from its place of privilege in the construction and communication of our understanding of global warming and its local consequences

The paradox of being a woman teacher

In this article I follow genealogical lines of analysis in an attempt to map the different discourses and practices that interweave women’s position in education today. I have theorised education as a nexus of created paradoxical spaces, where the female self has attempted to surpass closed boundaries and to question the dichotomy of the feminised private and/or the masculine public. I have also considered the importance of time restrictions upon women’s lives and have paid attention to the multifarious ways these lives are highly structured by specific space/time regulations. The genealogical cartography I have drawn, depicts various positions, where the female self has created parodic unities and temporary coalitions. Finally in tracing exit points that education has offered women, I have considered some of the implications of feminist theories for the subversion of the various dilemmas and dichotomies the female subject has lived through

Vulvovaginal Trichosporonosis

Objective: Isolation of Trichosporon species from vaginal secretions is a rare event, and no data are available on its pathogenic role. A case series is presented to determine the pathogenic role of Trichosporon species in vulvovaginal infections. Methods: We performed a retrospective chart review of patients seen in the W.S.U. Vaginitis Clinic in order to identify patients from whom Trichosporon species were isolated. Results: Between 1986 and 2001, a total of 13 patients had a total of 18 positive vaginal cultures for Trichosporon species. All 18 vaginal isolates were T. inkin. In general, positive vaginal cultures were accompanied by low yeast colony counts. Four out of 18 positive T. inkin cultures were obtained from visits by asymptomatic patients. Of the remaining 14 positive T. inkin cultures from patients with symptoms, nine out of 14 cultures had other diagnoses (Candida albicans, six cases; bacterial vaginosis, two cases; Trichomonas, one case). Five positive T. inkin cultures were obtained from visits at which patients had symptoms and no associated diagnosis. In only one of the five episodes could we establish a clear pathogenic role for Trichosporon. In this case the patient was treated with boric acid and had resolution of symptoms and a negative culture at follow-up. In-vitro susceptibility tests revealed that T. inkin was resistant to flucytosine and susceptible to all topical and oral azoles. Conclusions: T. inkin is occasionally found in vulvovaginal cultures and is usually a non-pathogen. Transient colonization tended to occur in women, usually of African—American origin, with major perturbations in vaginal flora (bacterial vaginosis and trichomoniasis) and increased pH. Pathogenic consequences of Trichosporon colonization appear to be rare

Randomized Controlled Trial of Ondansetron vs. Prochlorperazine in Adults in the Emergency Department

Objective: To compare the effectiveness of ondansetron and prochlorperazine to treat vomiting. Secondary objectives were the effectiveness of ondansetron and prochlorperazine to treat nausea and their tolerability.Methods: This was a prospective, randomized, active controlled, double-blinded study. Using a convenience sample, patients were randomized to either intravenous ondansetron 4mg (n=32) or prochlorperazine 10mg (n=32). The primary outcome was the percentage of patients with vomiting at 0-30, 31-60, and 61-120 minutes after the administration of ondansetron or prochlorperazine. Secondary outcomes were nausea assessed by a visual analog scale (VAS) at baseline, 0-30, 31-60, and 61-120 minutes after the administration of ondansetron or prochlorperazine and the percentage of patients with adverse effects (sedation, headache, akathisia, dystonia) to either drug. We performed statistical analyses on the VAS scales at each time point and did a subgroup analysis to examine if nausea scores were affected if the patient had vomited at baseline.Results: The primary identified cause for nausea and vomiting was flu-like illness or gastroenteritis (19%). The number of patients experiencing breakthrough vomiting at 0-30, 31-60, and 61-120 minutes was similar between groups for these time periods; however, more patients receiving ondansetron experienced vomiting overall (7 [22%] vs. 2[3.2%] patients, p=not significant). Nausea scores at baseline and 0-30 minutes were severe and similar between groups; however, at 31-60 and 61-120 minutes, patients receiving prochlorperazine had better control of nausea (24.9 vs. 43.7 mm, p=0.03; 16.8 vs. 34.3 mm, p=0.05). Sedation scores were similar between groups. There were no cases of extrapyramidal symptoms as assessed by the treating physician and there were four cases of akathisia (prochlorperazine=3 [9%], ondansetron=1[3%]).Conclusion: Prochlorperazine and ondansetron appear to be equally effective at treating vomiting in the emergency department. [West J Emerg Med. 2011;12(1):1-5.

Projected changes in the physical climate of the Gulf Coast and Caribbean

As the global climate warms due to increasing greenhouse gases, the regional climate of the Gulf of Mexico and Caribbean region will also change. This study presents the latest estimates of the expected changes in temperature, precipitation, tropical cyclone activity, and sea level. Changes in temperature and precipitation are derived from climate model simulations produced for the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4), by comparing projections for the mid- and late-21st century to the late 20th century and assuming a “middle-of-the-road” scenario for future greenhouse gas emissions. Regional simulations from the North America Regional Climate Change Program (NARCCAP) are used to corroborate the IPCC AR4 rainfall projections over the US portion of the domain. Changes in tropical cyclones and sea level are more uncertain, and our understanding of these variables has changed more since IPCC AR4 than in the case of temperature and precipitation. For these quantities, the current state of knowledge is described based on the recent peer-reviewed literature

An Empirical Relation between U.S. Tornado Activity and Monthly Environmental Parameters

In previous work the authors demonstrated an empirical relation, in the form of an index, between U.S. monthly tornado activity and monthly averaged environmental parameters. Here a detailed comparison is made between the index and reported tornado activity. The index is a function of two environmental parameters taken from the North American Regional Reanalysis: convective precipitation (cPrcp) and storm relative helicity (SRH). Additional environmental parameters are considered for inclusion in the index, among them convective available potential energy, but their inclusion does not significantly improve the overall climatological performance of the index. The aggregate climatological dependence of reported monthly U.S. tornado numbers on cPrcp and SRH is well described by the index, although it fails to capture nonsupercell and cool season tornadoes. The contributions of the two environmental parameters to the index annual cycle and spatial distribution are examined with the seasonality of cPrcp (maximum during summer) relative to SRH (maximum in winter) accounting for the index peak value in May. The spatial distribution of SRH establishes the central U.S. “tornado alley” of the index, while the spatial distribution of cPrcp enhances index values in the South and Southeast and suppresses them west of the Rockies and over elevation. At the scale of the NOAA climate regions, the largest deficiency of the index climatology occurs over the central region where the index peak in spring is too low and where the late summer drop-off in the reported number of tornadoes is poorly captured. This index deficiency is related to its sensitivity to SRH, and increasing the index sensitivity to SRH improves the representation of the annual cycle in this region. The ability of the index to represent the interannual variability of the monthly number of U.S. tornadoes can be ascribed during most times of the year to interannual variations of cPrcp rather than of SRH. However, both factors are important during the peak spring period. The index shows some skill in representing the interannual variability of monthly tornado numbers at the scale of NOAA climate regions