130 research outputs found
Application of Advanced Technologies to Small, Short-haul Air Transports
A study was conducted of the application of advanced technologies to small, short-haul transport aircraft. A three abreast, 30 passenger design for flights of approximately 100 nautical miles was evaluated. Higher wing loading, active flight control, and a gust alleviation system results in improved ride quality. Substantial savings in fuel and direct operating cost are forecast. An aircraft of this configuration also has significant benefits in forms of reliability and operability which should enable it to sell a total of 450 units through 1990, of which 80% are for airline use
Gravel pits support waterbird diversity in an urban landscape
We assessed the benefit of 11 gravel pits for the settlement of waterbird communities in an urbanized area lacking natural wetlands. Gravel pits captured 57% of the regional species pool of aquatic birds. We identified 39 species, among which five were regionally rare. We used the Self Organizing Map algorithm to calculate the probabilities of presence of species, and to bring out habitat conditions that predict assemblage patterns. The age of the pits did not correlate with assemblage composition and species richness. There was a positive influence of macrophyte cover on waterbird species richness. Larger pits did not support more species, but species richness increased with connectivity. As alternative wetland habitats, gravel pits are attractive to waterbirds, when they act as stepping stones that ensure connectivity between larger natural and/or artificial wetlands separated in space
Demographics, distribution and experiences of UK clinical academic trainees using GMC NTS Survey data
Involvement in research plays an integral role in the delivery of high-quality patient care, benefitting doctors, patients and employers. It is important that access to clinical academic training opportunities are inclusive and equitable. To better understand the academic trainee population, distribution of academic posts and their reported experience of clinical training, we analysed 53â477 anonymous responses from General Medical Council databases and the 2019 National Training Survey. Academic trainees are more likely to be men, and the gender divide begins prior to graduation. There are very low numbers of international medical graduates and less than full-time academic trainees. A small number of UK universities produce a greater prevalence of doctors successfully appointed to academic posts; subsequent academic training also clusters around these institutions. At more senior levels, academic trainees are significantly more likely to be of white ethnicity, although among UK graduates, no ethnicity differences were seen. Foundation academic trainees report a poorer experience of some aspects of their clinical training placements, with high workloads reported by all academic trainees. Our work highlights important disparities in the demographics of the UK clinical academic trainee population and raises concerns that certain groups of doctors face barriers accessing and progressing in UK academic training pathways
Neutron-proton pairing in the N=Z radioactive fp-shell nuclei 56Ni and 52Fe probed by pair transfer
The isovector and isoscalar components of neutron-proton pairing are
investigated in the N=Z unstable nuclei of the \textit{fp}-shell through the
two-nucleon transfer reaction (p,He) in inverse kinematics. The combination
of particle and gamma-ray detection with radioactive beams of Ni and
Fe, produced by fragmentation at the GANIL/LISE facility, made it
possible to carry out this study for the first time in a closed and an
open-shell nucleus in the \textit{fp}-shell. The transfer cross-sections for
ground-state to ground-state (J=0,T=1) and to the first (J=1,T=0) state
were extracted for both cases together with the transfer cross-section ratios
(0,T=1) /(1,T=0). They are compared with second-order
distorted-wave born approximation (DWBA) calculations. The enhancement of the
ground-state to ground-state pair transfer cross-section close to mid-shell, in
Fe, points towards a superfluid phase in the isovector channel. For the
"deuteron-like" transfer, very low cross-sections to the first (J=1,T=0)
state were observed both for \Ni\phe\, and \Fe\phe\, and are related to a
strong hindrance of this channel due to spin-orbit effect. No evidence for an
isoscalar deuteron-like condensate is observed.Comment: 7 pages, 4 figure
Cross-shell states in C: a test for p-sd interactions
The low-lying structure of C has been investigated via the
neutron-removal C reaction. Along with bound neutron sd-shell
hole states, unbound p-shell hole states have been firmly confirmed. The
excitation energies and the deduced spectroscopic factors of the cross-shell
states are an important measure of the neutron
configurations in C. Our results show a very good agreement with
shell-model calculations using the SFO-tls interaction for C. However, a
modification of the - and - monopole terms was applied in order
to reproduce the isotone O. In addition, the excitation energies
and spectroscopic factors have been compared to the first calculations of
C with the self-consistent Green's function method
employing the NNLO interaction. The results show the sensitivity to the
size of the shell gap and highlight the need of going beyond the current
truncation scheme in the theory
Comparative BAC-based mapping in the white-throated sparrow, a novel behavioral genomics model, using interspecies overgo hybridization
BACKGROUND
The genomics era has produced an arsenal of resources from sequenced organisms allowing researchers to target species that do not have comparable mapping and sequence information. These new "non-model" organisms offer unique opportunities to examine environmental effects on genomic patterns and processes. Here we use comparative mapping as a first step in characterizing the genome organization of a novel animal model, the white-throated sparrow (Zonotrichia albicollis), which occurs as white or tan morphs that exhibit alternative behaviors and physiology. Morph is determined by the presence or absence of a complex chromosomal rearrangement. This species is an ideal model for behavioral genomics because the association between genotype and phenotype is absolute, making it possible to identify the genomic bases of phenotypic variation.
FINDINGS
We initiated a genomic study in this species by characterizing the white-throated sparrow BAC library via filter hybridization with overgo probes designed for the chicken, turkey, and zebra finch. Cross-species hybridization resulted in 640 positive sparrow BACs assigned to 77 chicken loci across almost all macro-and microchromosomes, with a focus on the chromosomes associated with morph. Out of 216 overgos, 36% of the probes hybridized successfully, with an average number of 3.0 positive sparrow BACs per overgo.
CONCLUSIONS
These data will be utilized for determining chromosomal architecture and for fine-scale mapping of candidate genes associated with phenotypic differences. Our research confirms the utility of interspecies hybridization for developing comparative maps in other non-model organisms
Shape coexistence and mixing of low-lying 0+ states in 96Sr
The low energy excited 02,3 + states in 96Sr are amongst the most prominent examples of shape coexistence across the nuclear landscape. In this work, the neutron [2s1/2]2 content of the 01,2,3 + states in 96Sr was determined by means of the d(95Sr, p) transfer reaction at the TRIUMF-ISAC2 facility using the SHARC and TIGRESS arrays. Spectroscopic factors of 0.19(3) and 0.22(3) were extracted for the 96Sr ground and 1229 keV 0+ states, respectively, by fitting the experimental angular distributions to DWBA reaction model calculations. A detailed analysis of the Îł-decay of the isomeric 03 + state was used to determine a spectroscopic factor of 0.33(13). The experimental results are compared to shell model calculations, which predict negligible spectroscopic strength for the excited 0+ states in 96Sr. The strengths of the excited 02,3 + states were also analyzed within a two-level mixing model and are consistent with a mixing strength of a2=0.40(14) and a difference in intrinsic deformations of |ÎÎČ|=0.31(3). These results suggest coexistence of three different configurations in 96Sr and strong shape mixing of the two excited 0+ states
Shell evolution approaching the N=20 island of inversion : Structure of Mg 29
The island of inversion for neutron-rich nuclei in the vicinity of N=20 has become the testing ground par excellence for our understanding and modeling of shell evolution with isospin. In this context, the structure of the transitional nucleus Mg29 is critical. The first quantitative measurements of the single-particle structure of Mg29 are reported, using data from the d(Mg28, p Îł)Mg29 reaction. Two key states carrying significant 3 (f-wave) strength were identified at 2.40±0.10 (JÏ=5/2-) and 4.28±0.04 MeV (7/2-). New state-of-the-art shell-model calculations have been performed and the predictions are compared in detail with the experimental results. While the two lowest 7/2- levels are well described, the sharing of single-particle strength disagrees with experiment for both the 3/2- and 5/2- levels and there appear to be general problems with configurations involving the p3/2 neutron orbital and core-excited components. These conclusions are supported by an analysis of the neutron occupancies in the shell-model calculations
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