1,064 research outputs found
Evidence of a Metal Rich Galactic Bar from the Vertex Deviation of the Velocity Ellipsoid
We combine radial velocities, proper motions, and low resolution abundances
for a sample of 315 K and M giants in the Baade's Window (l,b)=(0.9,-4)
Galactic bulge field. The velocity ellipsoid of stars with [Fe/H]>-0.5 dex
shows a vertex deviation in the plot of radial versus transverse velocity,
consistent with that expected from a population with orbits supporting a bar.
We demonstrate that the significance of this vertex deviation using
non-parametric rank correlation statistic is >99%. The velocity ellipsoid for
the metal poor ([FeH]<-0.5) part of the population shows no vertex deviation
and is consistent with an isotropic, oblate rotating population. We find no
evidence for kinematic subgroups, but there is a mild tendency for the vertical
velocity dispersion sigma_b to decrease with increasing metallicity.Comment: 4 pages, ApJ Letters, submitte
Binding branched and linear DNA structures: from isolated clusters to fully bonded gels
The proper design of DNA sequences allows for the formation of well defined
supramolecular units with controlled interactions via a consecution of
self-assembling processes. Here, we benefit from the controlled DNA
self-assembly to experimentally realize particles with well defined valence,
namely tetravalent nanostars (A) and bivalent chains (B). We specifically focus
on the case in which A particles can only bind to B particles, via
appropriately designed sticky-end sequences. Hence AA and BB bonds are not
allowed. Such a binary mixture system reproduces with DNA-based particles the
physics of poly-functional condensation, with an exquisite control over the
bonding process, tuned by the ratio, r, between B and A units and by the
temperature, T. We report dynamic light scattering experiments in a window of
Ts ranging from 10{\deg}C to 55{\deg}C and an interval of r around the
percolation transition to quantify the decay of the density correlation for the
different cases. At low T, when all possible bonds are formed, the system
behaves as a fully bonded network, as a percolating gel and as a cluster fluid
depending on the selected r.Comment: 15 pages, 11 figure
Fate and Behavior of Gunshot Residue-A Review
A review of the literature concerning the fate and behaviour of gunshot residue (GSR) is presented. A number of concomitant parameters including firearm and ammunition type, plume and GSR material characteristics, travel distances, chemical composition and GSR morphology are critically discussed in relation to their effects on the distribution and deposition, transfer and persistence processes of GSR. The underlying mechanisms associated with such processes are also considered. Knowledge of these processes on GSR materials could provide valuable information concerning scene preservation and subsequent forensic sampling. The number of GSR particles deposited can vary significantly with each firearm discharge, highlighting the potential to produce distinctive data in each individual case. With the continual development and compositional changes of new ammunition types, further evaluation of the effect these processes may have on GSR evidence and their possible influence on the interpretation of the analytical results should be given due consideration
Probabilistic linkage without personal information successfully linked national clinical datasets: Linkage of national clinical datasets without patient identifiers using probabilistic methods.
BACKGROUND: Probabilistic linkage can link patients from different clinical databases without the need for personal information. If accurate linkage can be achieved, it would accelerate the use of linked datasets to address important clinical and public health questions. OBJECTIVE: We developed a step-by-step process for probabilistic linkage of national clinical and administrative datasets without personal information, and validated it against deterministic linkage using patient identifiers. STUDY DESIGN AND SETTING: We used electronic health records from the National Bowel Cancer Audit (NBOCA) and Hospital Episode Statistics (HES) databases for 10,566 bowel cancer patients undergoing emergency surgery in the English National Health Service. RESULTS: Probabilistic linkage linked 81.4% of NBOCA records to HES, versus 82.8% using deterministic linkage. No systematic differences were seen between patients that were and were not linked, and regression models for mortality and length of hospital stay according to patient and tumour characteristics were not sensitive to the linkage approach. CONCLUSION: Probabilistic linkage was successful in linking national clinical and administrative datasets for patients undergoing a major surgical procedure. It allows analysts outside highly secure data environments to undertake linkage while minimising costs and delays, protecting data security, and maintaining linkage quality
Structural and functional characterization of the Redβ recombinase from bacteriophage λ
The Red system of bacteriophage λ is responsible for the genetic rearrangements that contribute to its rapid evolution and has been successfully harnessed as a research tool for genome manipulation. The key recombination component is Redβ, a ring-shaped protein that facilitates annealing of complementary DNA strands. Redβ shares functional similarities with the human Rad52 single-stranded DNA (ssDNA) annealing protein although their evolutionary relatedness is not well established. Alignment of Rad52 and Redβ sequences shows an overall low level of homology, with 15% identity in the N-terminal core domains as well as important similarities with the Rad52 homolog Sak from phage ul36. Key conserved residues were chosen for mutagenesis and their impact on oligomer formation, ssDNA binding and annealing was probed. Two conserved regions were identified as sites important for binding ssDNA; a surface basic cluster and an intersubunit hydrophobic patch, consistent with findings for Rad52. Surprisingly, mutation of Redβ residues in the basic cluster that in Rad52 are involved in ssDNA binding disrupted both oligomer formation and ssDNA binding. Mutations in the equivalent of the intersubunit hydrophobic patch in Rad52 did not affect Redβ oligomerization but did impair DNA binding and annealing. We also identified a single amino acid substitution which had little effect on oligomerization and DNA binding but which inhibited DNA annealing, indicating that these two functions of Redβ can be separated. Taken together, the results provide fresh insights into the structural basis for Redβ function and the important role of quaternary structure
Can clinical prediction tools predict the need for computed tomography in blunt abdominal? A systematic review
Risk of venous thromboembolism in users of oral contraceptives containing drospirenone or levonorgestrel: nested case-control study based on UK General Practice Research Database
Objective To examine the risk of non-fatal idiopathic venous thromboembolism in current users of a combined oral contraceptive containing drospirenone, relative to current users of preparations containing levonorgestrel
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Innovating Pedagogy 2015: Open University Innovation Report 4
This series of reports explores new forms of teaching, learning and assessment for an interactive world, to guide teachers and policy makers in productive innovation. This fourth report proposes ten innovations that are already in currency but have not yet had a profound influence on education. To produce it, a group of academics at the Institute of Educational Technology in The Open University collaborated with researchers from the Center for Technology in Learning at SRI International. We proposed a long list of new educational terms, theories, and practices. We then pared these down to ten that have the potential to provoke major shifts in educational practice, particularly in post-school education. Lastly, we drew on published and unpublished writings to compile the ten sketches of new pedagogies that might transform education. These are summarised below in an approximate order of immediacy and timescale to widespread implementation
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