Near infrared spectroscopy of W51 IRS-2

Near-infrared spectra at 2.95-3.5 μm and 3.99-10 μm have been obtained towards W51 IRS-2 and its surroundings, in order to investigate the spatial variations in intensity of the 3.28 μm unidentified feature and the 4.05 μm Brackett-α line. The Br-α and 3.28 μm features occupy a broadly similar spatial zone, which is characterised by an unresolved core responsible for most of the emission, and an extended and considerably weaker halo. Grain properties required to excite the 4.28 microns line, the nature of the 3.28 μm emission, and its relation to the source structure are discussed

Inorganic Surface Passivation of PbS Nanocrystals resulting in Strong Photoluminescent Emission

Strong photoluminescent emission has been obtained from 3 nm PbS nanocrystals in aqueous colloidal solution, following treatment with CdS precursors. The observed emission can extend across the entire visible spectrum and usually includes a peak near 1.95 eV. We show that much of the visible emission results from absorption by higher-lying excited states above 3.0 eV with subsequent relaxation to and emission from states lying above the observed band-edge of the PbS nanocrystals. The fluorescent lifetimes for this emission are in the nanosecond regime, characteristic of exciton recombination.Comment: Preprint, 23 pages, 6 figure

A perfect storm: An archaeological management crisis in the Mississippi River Delta

Engineered projects resulting in unintended consequences, coastal erosion, subsidence, and sea-level rise are rapidly destroying archaeological sites in the Mississippi River Delta (MRD). The processes of site obliteration are intensifying and accelerating due to anthropogenic transformation of the environment, including cumulative engineered alterations of the landscape and climate change. Combined with increased inundation and erosion from storm surges, hundreds of terrestrial sites formerly located on natural levees, barrier islands, and other coastal landforms are progressively eroded, redeposited, deeply buried, and submerged. These include thousand-year-old earthen mounds and shell middens constructed by Native Americans, as well as centuries-old fishing communities along the coast. These irreplaceable cultural properties can provide crucial information on the unique history and ecology of the MRD. Ongoing studies include consulting with interested parties and implementing data sharing agreements. Re- searchers have formed a consortium of universities and state and federal agencies, and are partnering with culturally affiliated Native American tribes, descendant groups, and coastal communities. The consortium is developing a robust GIS-enabled risk matrix for analyzing threats and effects to endangered sites. It is using the risk matrix to select 30 sites for monitoring, assessment, aerial photogrammetry, and recording environmental data on water table fluctuations. Analysis of action-based scientific data on these imperiled and rapidly disappearing places is urgently needed and will provide the impetus and baseline for future studies. Otherwise, ongoing site destruction will erase any remaining opportunities for learning about Louisiana’s deep history and diverse cultural heritage

Levels of genetic polymorphism: marker loci versus quantitative traits

Species are the units used to measure ecological diversity and alleles are the units of genetic diversity. Genetic variation within and among species has been documented most extensively using allozyme electrophoresis. This reveals wide differences in genetic variability within, and genetic distances among, species, demonstrating that species are not equivalent units of diversity. The extent to which the pattern observed for allozymes can be used to infer patterns of genetic variation in quantitative traits depends on the forces generating and maintaining variability. Allozyme variation is probably not strictly neutral but, nevertheless, heterozygosity is expected to be influenced by population size and genetic distance will be affected by time since divergence. The same is true for quantitative traits influenced by many genes and under weak stabilizing selection. However, the limited data available suggest that allozyme variability is a poor predictor of genetic variation in quantitative traits within populations. It is a better predictor of general phenotypic divergence and of postzygotic isolation between populations or species, but is only weakly correlated with prezygotic isolation. Studies of grasshopper and planthopper mating signal variation and assortative mating illustrate how these characters evolve independently of general genetic and morphological variation. The role of such traits in prezygotic isolation, and hence speciation, means that they will contribute significantly to the diversity of levels of genetic variation within and among species

Tool support for security-oriented virtual research collaborations

Collaboration is at the heart of e-Science and e-Research more generally. Successful collaborations must address both the needs of the end user researchers and the providers that make resources available. Usability and security are two fundamental requirements that are demanded by many collaborations and both concerns must be considered from both the researcher and resource provider perspective. In this paper we outline tools and methods developed at the National e-Science Centre (NeSC) that provide users with seamless, secure access to distributed resources through security-oriented research environments, whilst also allowing resource providers to define and enforce their own local access and usage policies through intuitive user interfaces. We describe these tools and illustrate their application in the ESRC-funded Data Management through e-Social Science (DAMES) and the JISC-funded SeeGEO projects

Propofol Sedation for Oesophago-Gastro-Duodenoscopy

A questionnaire was sent to 53 patients who had undergone an upper gastrointestinal endoscopy under total intravenous anaesthesia (TIVA) using intermittent Propofol. All of the patients would accept the same technique again. Out of 20 patients who had previously had the procedure performed under Diazepam sedation, 18 preferred the use of Propofol. This technique can only be used with an anaesthetist present

The Inverse of the Complex Gamma Function

We consider the functional inverse of the Gamma function in the complex plane, where it is multi-valued, and define a set of suitable branches by proposing a natural extension from the real case

Access to primary care and the route of emergency admission to hospital: retrospective analysis of national hospital administrative data

BACKGROUND: The UK government is pursuing policies to improve primary care access, as many patients visit accident and emergency (A and E) departments after being unable to get suitable general practice appointments. Direct admission to hospital via a general practitioner (GP) averts A and E use, and may reduce total hospital costs. It could also enhance the continuity of information between GPs and hospital doctors, possibly improving healthcare outcomes. OBJECTIVE: To determine whether primary care access is associated with the route of emergency admission-via a GP versus via an A and E department. METHODS: Retrospective analysis of national administrative data from English hospitals for 2011-2012. Adults admitted in an emergency (unscheduled) for ≥1 night via a GP or an A and E department formed the study population. The measure of primary care access-the percentage of patients able to get a general practice appointment on their last attempt-was derived from a large, nationally representative patient survey. Multilevel logistic regression was used to estimate associations, adjusting for patient and admission characteristics. RESULTS: The analysis included 2 322 112 emergency admissions (81.9% via an A and E department). With a 5 unit increase in the percentage of patients able to get a general practice appointment on their last attempt, the adjusted odds of GP admission (vs A and E admission) was estimated to increase by 15% (OR 1.15, 95% CI 1.12 to 1.17). The probability of GP admission if ≥95% of appointment attempts were successful in each general practice was estimated to be 19.6%. This probability reduced to 13.6% when <80% of appointment attempts were successful. This equates to 139 673 fewer GP admissions (456 232 vs 316 559) assuming no change in the total number of admissions. Associations were consistent in direction across geographical regions of England. CONCLUSIONS: Among hospital inpatients admitted as an emergency, patients registered to more accessible general practices were more likely to have been admitted via a GP (vs an A and E department). This furthers evidence suggesting that access to general practice is related to use of emergency hospital services in England. The relative merits of the two admission routes remain unclear