Methodology for Assessing a Boiling Liquid Expanding Vapor Explosion (BLEVE) Blast Potential

Composite Vessels are now used to store a variety of fluids or gases including cryogenic fluids under pressure. Sudden failure of these vessels under certain conditions can lead to a potentially catastrophic vapor expansion if thermal control is not maintained prior to failure. This can lead to a "Boiling Liquid Expanding Vapor Explosion" or BLEVE

Development and evaluation of a multiple-locus variable-number tandem-repeats analysis assay for subtyping Salmonella Typhi strains from sub-Saharan Africa

Purpose: Molecular epidemiological investigations of the highly clonal Salmonella enterica subspecies enterica serovar Typhi (S. Typhi) are important in outbreak detection and in tracking disease transmission. In this study, we developed and evaluated a multiple-locus variable-number tandem-repeats (VNTR) analysis (MLVA) assay for characterization of S. Typhi isolates from sub-Saharan Africa. Methodology: Twelve previously reported VNTR loci were evaluated and an MLVA assay consisting of five polymorphic loci was adopted. The MLVA assay was developed for use on capillary electrophoresis systems by testing a collection of 50 S. Typhi isolates. This S. Typhi strain panel consisted of six outbreak related isolates and 44 epidemiologically unlinked isolates. Amongst these were nine S.Typhi haplotype H58 isolates. Results: The MLVA assay characterized the 50 isolates into 47 MLVA profiles while PFGE analysis of the same isolates revealed 34 pulsotypes. MLVA displayed higher discriminatory power (Simpson’s index of diversity (DI) 0.998 [95% confidence interval (CI) 0.995–1.000)] as compared to pulsed-field gel electrophoresis [Simpson’s DI 0.984 (95% CI 0.974–0.994)]. Conclusion: The MLVA assay presented in this study is a simple, rapid and more accessible tool that serves as a good alternative to other molecular subtyping methods for S. Typhi

Composite Overwrapped Pressure Vessel (COPV) Stress Rupture Testing

This paper reports stress rupture testing of Kevlar(TradeMark) composite overwrapped pressure vessels (COPVs) at NASA White Sands Test Facility. This 6-year test program was part of the larger effort to predict and extend the lifetime of flight vessels. Tests were performed to characterize control parameters for stress rupture testing, and vessel life was predicted by statistical modeling. One highly instrumented 102-cm (40-in.) diameter Kevlar(TradeMark) COPV was tested to failure (burst) as a single-point model verification. Significant data were generated that will enhance development of improved NDE methods and predictive modeling techniques, and thus better address stress rupture and other composite durability concerns that affect pressure vessel safety, reliability and mission assurance

Pollination and dispersal trait spectra recover faster than the growth form spectrum during spontaneous succession in sandy old‐fields

Question: Spontaneous succession is the most natural and cost‐effective solution for grassland restoration. However, little is known about the time required for the recovery of grassland functionality, i.e., for the recovery of reproductive and vegetative processes typical of pristine grasslands. Since these processes operate at different scales, we addressed the question: do reproductive and vegetative processes require different recovery times during spontaneous succession? Location: Kiskunság sand region (Central Hungary). Methods: As combinations of plant traits can be used to highlight general patterns in ecological processes, we compared reproductive (pollination‐ and dispersal‐related) and vegetative (growth form) traits between recovered grasslands of different age (<10 years old; 10–20 years old; 20–40 years old) and pristine grasslands. Results: During spontaneous succession, the reproductive trait spectra became similar to those of pristine grasslands earlier than the vegetative ones. In arable land abandoned for 10 years, pollination‐ and dispersal‐related trait spectra did not show significant difference to those of pristine grasslands; anemophily and anemochory were the prevailing strategies. Contrarily, significant differences in the growth form spectrum could be observed even after 40 years of abandonment; in recovered grasslands erect leafy species prevailed, while the fraction of dwarf shrubs and tussock‐forming species was significantly lower than in pristine grasslands. Conclusions: The recovery of the ecological processes of pristine grasslands might require different amounts of time, depending on the spatial scale at which they operate. The reproductive trait spectra recovered earlier than the vegetative one, since reproductive attributes first determine plant species sorting at the regional level towards their respective habitats. The recovery of the vegetative trait spectrum needs more time as vegetative‐based interactions operate on a smaller spatial scale. Thus, vegetative traits might be more effective in the long‐term assessment of restoration success than the reproductive ones

Early Vegetation Development on an Exposed Reservoir: Implications for Dam Removal

The 4-year drawdown of Horsetooth Reservoir, Colorado, for dam maintenance, provides a case study analog of vegetation response on sediment that might be exposed from removal of a tall dam. Early vegetation recovery on the exposed reservoir bottom was a combination of (1) vegetation colonization on bare, moist substrates typical of riparian zones and reservoir sediment of shallow dams and (2) a shift in moisture status from mesic to the xeric conditions associated with the pre-impoundment upland position of most of the drawdown zone. Plant communities changed rapidly during the first four years of exposure, but were still substantially different from the background upland plant community. Predictions from the recruitment box model about the locations of Populus deltoides subsp. monilifera (plains cottonwood) seedlings relative to the water surface were qualitatively confirmed with respect to optimum locations. However, the extreme vertical range of water surface elevations produced cottonwood seed regeneration well outside the predicted limits of drawdown rate and height above late summer stage. The establishment and survival of cottonwood at high elevations and the differences between the upland plant community and the community that had developed after four years of exposure suggest that vegetation recovery following tall dam removal will follow a trajectory very different from a simple reversal of the response to dam construction, involving not only long time scales of establishment and growth of upland vegetation, but also possibly decades of persistence of legacy vegetation established during the reservoir to upland transition

Building Babies - Chapter 16

In contrast to birds, male mammals rarely help to raise the offspring. Of all mammals, only among rodents, carnivores, and primates, males are sometimes intensively engaged in providing infant care (Kleiman and Malcolm 1981). Male caretaking of infants has long been recognized in nonhuman primates (Itani 1959). Given that infant care behavior can have a positive effect on the infant’s development, growth, well-being, or survival, why are male mammals not more frequently involved in “building babies”? We begin the chapter defining a few relevant terms and introducing the theory and hypotheses that have historically addressed the evolution of paternal care. We then review empirical findings on male care among primate taxa, before focusing, in the final section, on our own work on paternal care in South American owl monkeys (Aotus spp.). We conclude the chapter with some suggestions for future studies.Deutsche Forschungsgemeinschaft (HU 1746/2-1) Wenner-Gren Foundation, the L.S.B. Leakey Foundation, the National Geographic Society, the National Science Foundation (BCS-0621020), the University of Pennsylvania Research Foundation, the Zoological Society of San Dieg

Part IV. Human infections and antibiotic resistance

South Africa has a high burden of infectious diseases, including a large portion that are of bacterial origin. This section reviews the national burden of disease and levels of antibiotic resistance in common bacterial infections in the human population. The consequences of resistance on clinical outcomes, through either treatment failures or the development of more virulent infections, are largely unknown. The full impact of antibiotic resistance on health in South Africa therefore remains to be assessed.http://www.samj.org.z

Shifts in Species Composition Constrain Restoration of Overgrazed Grassland Using Nitrogen Fertilization in Inner Mongolian Steppe, China

Long-term livestock over-grazing causes nitrogen outputs to exceed inputs in Inner Mongolia, suggesting that low levels of nitrogen fertilization could help restore grasslands degraded by overgrazing. However, the effectiveness of such an approach depends on the response of production and species composition to the interactive drivers of nitrogen and water availability. We conducted a five-year experiment manipulating precipitation (NP: natural precipitation and SWP: simulated wet year precipitation) and nitrogen (0, 25 and 50 kg N ha-1 yr-1) addition in Inner Mongolia. We hypothesized that nitrogen fertilization would increase forage production when water availability was relatively high. However, the extent to which nitrogen would co-limit production under average or below average rainfall in these grasslands was unknown

Effects of varying organic matter content on the development of green roof vegetation: a six year experiment

Green roofs can potentially be used to tackle a variety of environmental problems, and can be used as development mitigation for the loss of ground-based habitats. Brown (biodiversity) roofs are a type of green roof designed to imitate brownfield habitat, but the best way of engineering these habitats requires more research. We tested the effects of altering organic matter content on the development of vegetation assemblages of experimental brown (biodiversity) roof mesocosms. Three mulch treatments were tested: (1) Sandy loam, where 10mm of sandy loam mulch (about 3% organic matter by dry weight) was added to 100mm of recycled aggregate; (2) Compost, where the mulch also contained some garden compost (about 6% organic matter by dry weight); and (3) No mulch, where no mulch was added. Mesocosms were seeded with a wildflower mix that included some Sedum acre, and vegetation development was investigated over a six-year period. Species richness, assemblage character, number of plants able to seed, and above-ground plant biomass were measured. Drought disturbance was an important control on plant assemblages in all mulch treatments, but there were significant treatment response interactions. The more productive Compost treatment was associated with larger plant coverage and diversity before the occurrence of a sequence of drought disturbances, but was more strongly negatively affected by the disturbances than the two less productive treatments. We suggest that this was due to the over-production of plant biomass in the more productive treatment, which made the plants more vulnerable to the effects of drought disturbance, leading to a kind of 'boom-bust' assemblage dynamic. The 'ideal' amount of added organic matter for these green roof systems was very low, but other types of green roof that have a larger water holding capacity, and/or more drought resistant plant floras, will likely require more organic matter or fertiliser. Nonetheless, nutrient-supported productivity in green roof systems should be kept low in order to avoid boom-bust plant assemblage dynamics. Research into the best way of engineering green roof habitats should take place over a long enough multi-year time period to include the effects of temporally infrequent disturbances

Systemic shigellosis in South Africa

BACKGROUND: Systemic disease due to shigellae is associated with human immunodeficiency virus (HIV), malnutrition, and other immunosuppressed states. We examined the clinical and microbiologic characteristics of systemic shigellosis in South Africa, where rates of HIV infection are high. METHODS: From 2003 to 2009, 429 cases of invasive shigellosis were identified through national laboratory-based surveillance. At selected sites, additional information was captured on HIV serostatus and outcome. Isolates were serotyped and antimicrobial susceptibility testing performed. RESULTS: Most cases of systemic shigellosis were diagnosed on blood culture (408 of 429 cases; 95%). HIV prevalence was 67% (80 of 120 cases), highest in patients aged 5–54 years, and higher among females (55 of 70 cases; 79%) compared with males (25 of 48 cases; 52%; P 5 .002). HIV-infected people were 4.1 times more likely to die than HIV-uninfected cases (case-fatality ratio, 29 of 78 HIV-infected people [37%] vs 5 of 40 HIV-uninfected people [13%]; P 5 .008; 95% confidence interval [CI], 1.5–11.8). The commonest serotype was Shigella flexneri 2a (89 of 292 serotypes [30.5%]). Pentavalent resistance occurred in 120 of 292 isolates (41.1%). There was no difference in multidrug resistance between HIV-infected patients (33 of 71 [46%]) and uninfected patients (12 of 33 [36%]; 95% CI, .65–3.55). CONCLUSIONS: Systemic shigellosis is associated with HIV-infected patients, primarily in older girls and women, potentially due to the burden of caring for sick children in the home; interventions need to be targeted here. Death rates are higher in HIV-infected versus uninfected individuals.The US Agency for International Development’s Antimicrobial Resistance Initiative, transferred via a cooperative agreement (grant U60/CCU022088) from the Centers for Disease Control and Prevention (CDC), Atlanta, Georgia. For 2007–2009, it was supported by the Departments of Health and Human Services (HHS) CDC, the National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention (NCHHSTP), the Global AIDS Program (GAP) Cooperative Agreement (U62/PSO022901). P. C.-G. and S. M. are funded through grant U60/CCU022088.http://cid.oxfordjournals.org