2,801 research outputs found
In situ apparatus for the study of clathrate hydrates relevant to solar system bodies using synchrotron X-ray diffraction and Raman spectroscopy
Clathrate hydrates are believed to play a significant role in various solar
system environments, e.g. comets, and the surfaces and interiors of icy
satellites, however the structural factors governing their formation and
dissociation are poorly understood. We demonstrate the use of a high pressure
gas cell, combined with variable temperature cooling and time-resolved data
collection, to the in situ study of clathrate hydrates under conditions
relevant to solar system environments. Clathrates formed and processed within
the cell are monitored in situ using synchrotron X-ray powder diffraction and
Raman spectroscopy. X-ray diffraction allows the formation of clathrate
hydrates to be observed as CO2 gas is applied to ice formed within the cell.
Complete conversion is obtained by annealing at temperatures just below the ice
melting point. A subsequent rise in the quantity of clathrate is observed as
the cell is thermally cycled. Four regions between 100-5000cm-1 are present in
the Raman spectra that carry features characteristic of both ice and clathrate
formation. This novel experimental arrangement is well suited to studying
clathrate hydrates over a range of temperature (80-500K) and pressure
(1-100bar) conditions and can be used with a variety of different gases and
starting aqueous compositions. We propose the increase in clathrate formation
observed during thermal cycling may be due to the formation of a quasi
liquid-like phase that forms at temperatures below the ice melting point, but
which allows easier formation of new clathrate cages, or the retention and
delocalisation of previously formed clathrate structures, possibly as amorphous
clathrate. The structural similarities between hexagonal ice, the quasi
liquid-like phase, and crystalline CO2 hydrate mean that differences in the
Raman spectrum are subtle; however, all features out to 5000cm-1 are diagnostic
of clathrate structure.Comment: Astronomy & Astrophysics, in press. 6 page
Vulnerability and the Erosion of Seismic Culture in Mountainous Central Asia
Vulnerability to earthquake disasters in mountainous regions frequently escapes investigation and analysis. The tragic and costly earthquake disasters that have recently occurred in Central Asia have spurred important questions among local, regional, and international policymakers, scientists, and social activists regarding the root causes of earthquake vulnerability. Drawing on an analysis of recent earthquake disasters in Kyrgyzstan, Tajikistan, Afghanistan, and Pakistan, this article explores the concept of “seismic culture” (Degg and Homan 2005) in relation to vulnerability. Specifically, it argues that diminishing levels of indigenous hazard knowledge, demographic shifts, gendered livelihood transformations, and the lack of public access to science- based earthquake information have contributed to overall low levels of seismic cultures of prevention in the region. A major finding of the study points to the particular role of women in helping to redress the erosion of seismic culture, thereby bolstering local resilience, earthquake preparedness, and disaster risk reduction
Hiding behind the Corporate Veil: Employer Abuse of the Corporate Form to Avoid or Deny Workers\u27 Collectively Bargained and Statutory Rights
Non-aqueous formation of the calcium carbonate polymorph vaterite: astrophysical implications
We study the formation of calcium carbonate, through the solid-gas
interaction of amorphous Ca-silicate with gaseous CO2, at elevated pressures,
and link this to the possible presence of calcium carbonate in a number of
circumstellar and planetary environments. We use in-situ synchrotron X-Ray
powder diffraction to obtain detailed structural data pertaining to the
formation of the crystalline calcium carbonate phase vaterite and its evolution
with temperature. We found that the metastable calcium carbonate phase vaterite
was formed alongside calcite, at elevated CO2 pressure, at room temperature and
subsequently remained stable over a large range of temperature and pressure. We
report the formation of the calcium carbonate mineral vaterite whilst
attempting to simulate carbonate dust grain formation in astrophysical
environments. This suggests that vaterite could be a mineral component of
carbonate dust and also presents a possible method of formation for vaterite
and its polymorphs on planetary surfaces.Comment: Astronomy and Astrophysics, in pres
Informational Challenges in Early Disaster Response: The Massive Oso/SR530 Landslide 2014 as Case in Point
In disasters, and more so in catastrophes, one of the most daunting problems to professional responders is gaining situational awareness. Unfortunately, truly actionable information (intelligence) is missing in the first days and even weeks of responding. Consequently, incomplete situational awareness brings on a distorted common operating picture leading to suboptimal direction of responses, so more lives are lost, and more damage is inflicted. This study reports on the challenges emergency responders faced in the immediate aftermath of the 2014 massive landslide near Oso, WA. Over a hundred agencies were involved in the response, which presented a huge coordination task for the incident command. This study identifies and describes various challenges in the early response and also discusses recommendations on how to tackle and potentially mitigate the chal- lenges identified in future responses
Influenza vaccination coverage among an urban pediatric asthma population: Implications for population health
Introduction Asthma is the most common chronic disease in children. Children with asthma are at high risk for complications from influenza; however annual influenza vaccination rates for this population are suboptimal. The overall aim of this study was to describe the characteristics of a high-risk population of children with asthma presenting to an urban pediatric emergency department according to influenza vaccination status. Methods The study was a retrospective chart review of 4355 patients aged 2 to 18 years evaluated in a Michigan pediatric emergency department (PED) between November 1, 2017 and April 30, 2018 with an ICD-10-CM code for asthma (J45.x). Eligible patient PED records were matched with influenza vaccination records for the 2017–2018 influenza season from the Michigan Care Improvement Registry. Geospatial analysis was employed to examine the distribution of influenza vaccination status. Results 1049 patients (30.9%) with asthma seen in the PED had received an influenza vaccine. Influenza vaccination coverage varied by Census Tract, ranging from 10% to \u3e 99%. Most vaccines were administered in a primary care setting (84.3%) and were covered by public insurance (76.8%). The influenza vaccination rate was lowest for children aged 5–11 years (30.0%) and vaccination status was associated with race (p\u3c0.001) and insurance type (p\u3c0.001). Conclusions Identification of neighborhood Census Tract and demographic groups with suboptimal influenza vaccination could guide development of targeted public health interventions to improve vaccination rates in high-risk patients. Given the morbidity and mortality associated with pediatric asthma, a data-driven approach may improve outcomes and reduce healthcare-associated costs for this pediatric population
A single dose of trichloroethylene given during development does not substantially alter markers of neuroinflammation in brains of adult mice
Trichloroethylene (TCE) is a widespread environmental contaminant associated with developmental immu- notoxicity and neurotoxicity. Previous studies have shown that MRLþ/þ mice exposed to TCE from gesta- tion through early-life demonstrate robust increases in inflammatory markers in peripheral CD4þ T-cells, as well as glutathione depletion and increased oxidative stress in cerebellum-associated with alterations in behavior. Since increased oxidative stress is associated with neuroinflammation, we hypothesized that neuroinflammatory markers could be altered relative to unexposed mice. MRLþ/þ mice were given 0.5mg/ml of TCE in vehicle or vehicle (water with 1% Alkamuls EL-620) from conception through early adulthood via drinking water to dams and then directly to post-weaning offspring. Animals were euthan- ized at 49days of age and levels of pro- and anti-inflammatory cytokines, density of T-cell staining, and micro-glial morphology were evaluated in brains to begin to ascertain a neuroinflammatory profile. Levels of IL-6 were decreased in female animals and while not statistically significant, and levels of IL-10 were higher in brains of exposed male and female animals. Supportive of this observation, although not statis- tically significant, the number of ameboid microglia was higher in exposed relative to unexposed animals. This overall profile suggests the emergence of an anti-inflammatory/neuroprotective phenotype in exposed animals, possibly as a compensatory response to neuroinflammation that is known to be induced by developmental exposure to TCE
Maternal fucosyltransferase 2 status affects the gut bifidobacterial communities of breastfed infants.
BackgroundIndividuals with inactive alleles of the fucosyltransferase 2 gene (FUT2; termed the 'secretor' gene) are common in many populations. Some members of the genus Bifidobacterium, common infant gut commensals, are known to consume 2'-fucosylated glycans found in the breast milk of secretor mothers. We investigated the effects of maternal secretor status on the developing infant microbiota with a special emphasis on bifidobacterial species abundance.ResultsOn average, bifidobacteria were established earlier and more often in infants fed by secretor mothers than in infants fed by non-secretor mothers. In secretor-fed infants, the relative abundance of the Bifidobacterium longum group was most strongly correlated with high percentages of the order Bifidobacteriales. Conversely, in non-secretor-fed infants, Bifidobacterium breve was positively correlated with Bifidobacteriales, while the B. longum group was negatively correlated. A higher percentage of bifidobacteria isolated from secretor-fed infants consumed 2'-fucosyllactose. Infant feces with high levels of bifidobacteria had lower milk oligosaccharide levels in the feces and higher amounts of lactate. Furthermore, feces containing different bifidobacterial species possessed differing amounts of oligosaccharides, suggesting differential consumption in situ.ConclusionsInfants fed by non-secretor mothers are delayed in the establishment of a bifidobacteria-laden microbiota. This delay may be due to difficulties in the infant acquiring a species of bifidobacteria able to consume the specific milk oligosaccharides delivered by the mother. This work provides mechanistic insight into how milk glycans enrich specific beneficial bacterial populations in infants and reveals clues for enhancing enrichment of bifidobacterial populations in at risk populations - such as premature infants
Early Scottish Monasteries and Prehistory: A Preliminary Dialogue
Reflecting oil the diversity of monastic attributes found in the east and west of Britain, the author proposes that prehistoric ritual practice was influential on monastic form. An argument is advanced that this was not based solely oil inspiration Front the landscape, nor oil conservative tradition, but oil the intellectual reconciliation of Christian and non-Christian ideas, with disparate results that account. for the differences in monumentality. Among more general matters tentatively credited with a prehistoric root are the cult of relics, the tonsure and the date of Easter
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