97 research outputs found
Computerâassisted learning as an alternative to didactic lectures: A study of teaching the physics of diagnostic imaging
A computerâassisted learning (CAL) package entitled Physics of Diagnostic Imaging was developed in 1995 to replace five hours of didactic lectures at the University of Glasgow Faculty of Veterinary Medicine, and has been available as an additional learning resource for students in the other five UK veterinary schools for over three years. The package was reviewed by peer experts and the reaction of the students to its use gauged by postâtask questionnaire administration, informal discussions and observation. To assess the effect of integration into the curriculum, analyses of fourthâyear degree examination results over a sixâyear period were carried out. Analyses of studentsâ examination results for preâ and postâCAL delivery of the diagnostic imaging course showed that performance in the CALâbased course was significantly higher than in other subjects. This confirmed that the courseware can be used to replace didactic lectures as part of a rich learning environment supported by other resources. Initial student resistance to lecture replacement with CAL occurred, but has lessened as the use of the package has become established in the curriculum
Compression ultrasonography for false femoral artery aneurysms: Hypocoagulability is a cause of failure
Objectives:false femoral artery aneurysm is an occasional complication of percutaneous cardiovascular radiological procedures. Compression ultrasonography causes thrombosis non-invasively, reducing need for operative intervention. The technique fails in a proportion of cases. Analysis was undertaken to identify causes of failure.Design:prospective open study.Materials and Methods:patients presenting with false femoral artery aneurysm since 1984 were identified from a computerised database (BIPAS). Since 1993 compression ultrasonography has been performed as first line treatment according to a standard protocol. Prospectively collected ultrasonographic data and case notes were reviewed to identify causes of failed compression.Results:false femoral artery aneurysm occurred as a complication in 32/26 687 (0.12%) cardiovascular radiological procedures. Eighteen aneurysms were treated by compression. The technique was successful in 11/18 (61%) cases but primary failure occurred in seven cases. Six out of seven had bleeding abnormalities (Chi-squared analysis with Yates correction 10.55, p=0.0012), four were anticoagulated and compression was subsequently successful following reversal of warfarin therapy in three of these patients. In 4/18 cases surgical repair was necessary.Conclusions:compression ultrasonography is an effective treatment of false femoral aneurysms, however, hypocoagulability is a significant cause of failure. For patients in whom anticoagulation cannot be reversed, primary surgical repair should be considered
The Theory of Brown Dwarfs and Extrasolar Giant Planets
Straddling the traditional realms of the planets and the stars, objects below
the edge of the main sequence have such unique properties, and are being
discovered in such quantities, that one can rightly claim that a new field at
the interface of planetary science and and astronomy is being born. In this
review, we explore the essential elements of the theory of brown dwarfs and
giant planets, as well as of the new spectroscopic classes L and T. To this
end, we describe their evolution, spectra, atmospheric compositions, chemistry,
physics, and nuclear phases and explain the basic systematics of
substellar-mass objects across three orders of magnitude in both mass and age
and a factor of 30 in effective temperature. Moreover, we discuss the
distinctive features of those extrasolar giant planets that are irradiated by a
central primary, in particular their reflection spectra, albedos, and transits.
Aspects of the latest theory of Jupiter and Saturn are also presented.
Throughout, we highlight the effects of condensates, clouds, molecular
abundances, and molecular/atomic opacities in brown dwarf and giant planet
atmospheres and summarize the resulting spectral diagnostics. Where possible,
the theory is put in its current observational context.Comment: 67 pages (including 36 figures), RMP RevTeX LaTeX, accepted for
publication in the Reviews of Modern Physics. 30 figures are color. Most of
the figures are in GIF format to reduce the overall size. The full version
with figures can also be found at:
http://jupiter.as.arizona.edu/~burrows/papers/rm
Search for Lorentz and CPT violation using sidereal time dependence of neutrino flavor transitions over a short baseline
A class of extensions of the Standard Model allows Lorentz and CPT violations, which can be identified
by the observation of sidereal modulations in the neutrino interaction rate. A search for such modulations
was performed using the T2K on-axis near detector. Two complementary methods were used in this study,
both of which resulted in no evidence of a signal. Limits on associated Lorentz and CPT-violating terms
from the Standard Model extension have been derived by taking into account their correlations in this
model for the first time. These results imply such symmetry violations are suppressed by a factor of more
than 10 20 at the GeV scale
Measurement of coherent production in low energy neutrino-Carbon scattering
We report the first measurement of the flux-averaged cross section for charged current coherent production on carbon for neutrino energies less than 1.5 GeV to a restricted final state phase space region in the T2K near detector, ND280. Comparisons are made with predictions from the Rein-Sehgal coherent production model and the model by Alvarez-Ruso {\it et al.}, the latter representing the first implementation of an instance of the new class of microscopic coherent models in a neutrino interaction Monte Carlo event generator. This results contradicts the null results reported by K2K and SciBooNE in a similar neutrino energy region
Whole-genome sequencing reveals host factors underlying critical COVID-19
Critical COVID-19 is caused by immune-mediated inflammatory lung injury. Host genetic variation influences the development of illness requiring critical care1 or hospitalization2,3,4 after infection with SARS-CoV-2. The GenOMICC (Genetics of Mortality in Critical Care) study enables the comparison of genomes from individuals who are critically ill with those of population controls to find underlying disease mechanisms. Here we use whole-genome sequencing in 7,491 critically ill individuals compared with 48,400 controls to discover and replicate 23 independent variants that significantly predispose to critical COVID-19. We identify 16 new independent associations, including variants within genes that are involved in interferon signalling (IL10RB and PLSCR1), leucocyte differentiation (BCL11A) and blood-type antigen secretor status (FUT2). Using transcriptome-wide association and colocalization to infer the effect of gene expression on disease severity, we find evidence that implicates multiple genesâincluding reduced expression of a membrane flippase (ATP11A), and increased expression of a mucin (MUC1)âin critical disease. Mendelian randomization provides evidence in support of causal roles for myeloid cell adhesion molecules (SELE, ICAM5 and CD209) and the coagulation factor F8, all of which are potentially druggable targets. Our results are broadly consistent with a multi-component model of COVID-19 pathophysiology, in which at least two distinct mechanisms can predispose to life-threatening disease: failure to control viral replication; or an enhanced tendency towards pulmonary inflammation and intravascular coagulation. We show that comparison between cases of critical illness and population controls is highly efficient for the detection of therapeutically relevant mechanisms of disease
Sympathetic skin response and patient satisfaction on long term follow up of thoracoscopic sympathectomy for hyperhidrosis
Objectives:To determine effect of sympathectomy for hyperhidrosis on sympathetic skin response (SSR) during long-term follow-up. Patient satisfaction was assessed and surgical complications noted.Design:Prospective, Open, Non-randomised study.Materials and Methods:Patients who had undergone bilateral thoracoscopic sympathectomy for hyperhidrosis underwent postoperative assessment of SSRs. A 15mA stimulus was applied over the median nerve contralateral to the sympathectomy and evoked electrodermal activity was recorded from the sympathectomised palm using a Dantec Counterpoint Mk 2. Patient satisfaction with surgery was assessed by questionaire and visual analogue score (0â1.0).Results:Of 26 patients, 21 were female. Mean (range) age was 23 (9â36) years. Mean (range) follow up was 39 (4â138) months. 12% of cases had residual or recurrent symptoms. Median (range) patient satisfaction was 0.83 (0.06â1.0). In 7/52 palms recurrent SSRs were not detected. Repeated measures analysis of variance found amplitude of SSR to be of low significance with respect to time since surgery (F=0.48; p=0.49) and incidence of compensatory sweating (F=2.38; p=0.14).Conclusion:Thoracoscopic sympathectomy for hyperhidrosis is an effective procedure. Following sympathectomy SSRs are not permanently abolished, but return of SSRs does not correspond with symptom recurrence. As such, SSRs are a poor tool for objective assessment of long-term outcome following sympathectomy
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