12,814 research outputs found
Polaroid film helps locate objects in inaccessible areas quickly
Polaroid film is used with conventional portable X ray equipment to locate and shoot items or objects in difficult areas. Polaroid film development time is about 20 seconds
Experimental evaluation of outer case blowing or bleeding of single stage axial flow compressor. Part I - Design of rotor and bleeding and blowing configurations
Rotor design to evaluate outer case blowing or bleeding of single stage axial flow compresso
Systematic review of the current status of cadaveric simulation for surgical training
Background:
There is growing interest in and provision of cadaveric simulation courses for surgical trainees. This is being driven by the need to modernize and improve the efficiency of surgical training within the current challenging training climate. The objective of this systematic review is to describe and evaluate the evidence for cadaveric simulation in postgraduate surgical training.
Methods:
A PRISMA‐compliant systematic literature review of studies that prospectively evaluated a cadaveric simulation training intervention for surgical trainees was undertaken. All relevant databases and trial registries were searched to January 2019. Methodological rigour was assessed using the widely validated Medical Education Research Quality Index (MERSQI) tool.
Results:
A total of 51 studies were included, involving 2002 surgical trainees across 69 cadaveric training interventions. Of these, 22 assessed the impact of the cadaveric training intervention using only subjective measures, five measured impact by change in learner knowledge, and 23 used objective tools to assess change in learner behaviour after training. Only one study assessed patient outcome and demonstrated transfer of skill from the simulated environment to the workplace. Of the included studies, 67 per cent had weak methodology (MERSQI score less than 10·7).
Conclusion:
There is an abundance of relatively low‐quality evidence showing that cadaveric simulation induces short‐term skill acquisition as measured by objective means. There is currently a lack of evidence of skill retention, and of transfer of skills following training into the live operating theatre
Superfluidity of bosons on a deformable lattice
We study the superfluid properties of a system of interacting bosons on a
lattice which, moreover, are coupled to the vibrational modes of this lattice,
treated here in terms of Einstein phonon model. The ground state corresponds to
two correlated condensates: that of the bosons and that of the phonons. Two
competing effects determine the common collective soundwave-like mode with
sound velocity , arising from gauge symmetry breaking: i) The sound velocity
(corresponding to a weakly interacting Bose system on a rigid lattice) in
the lowest order approximation is reduced due to reduction of the repulsive
boson-boson interaction, arising from the attractive part of phonon mediated
interaction in the static limit. ii) the second order correction to the sound
velocity is enhanced as compared to the one of bosons on a rigid lattice when
the the boson-phonon interaction is switched on due to the retarded nature of
phonon mediated interaction. The overall effect is that the sound velocity is
practically unaffected by the coupling with phonons, indicating the robustness
of the superfluid state. The induction of a coherent state in the phonon
system, driven by the condensation of the bosons could be of experimental
significance, permitting spectroscopic detections of superfluid properties of
the bosons. Our results are based on an extension of the Beliaev - Popov
formalism for a weakly interacting Bose gas on a rigid lattice to that on a
deformable lattice with which it interacts.Comment: 12 pages, 14 figures, to appear in Phys. Rev.
Using White Dish CMB Anisotropy Data to Probe Open and Flat-Lambda CDM Cosmogonies
We use data from the White Dish experiment to set limits on cosmic microwave
background radiation anisotropies in open and spatially-flat-Lambda cold dark
matter cosmogonies. We account for the White Dish calibration uncertainty, and
marginalize over the offset and gradient removed from the data. Our 2-sigma
upper limits are larger than those derived previously. These upper limits are
consistent with those derived from the -DMR data for all models tested.Comment: 17 pages of latex. Uses aasms4.sty. 4 figures included. Submitted to
ApJ
Human subjective response to steering wheel vibration caused by diesel engine idle
This study investigated the human subjective response to steering wheel vibration of the type caused by a four-cylinder diesel engine idle in passenger cars. Vibrotactile perception was assessed using sinusoidal amplitude-modulated vibratory stimuli of constant energy level (r.m.s. acceleration, 0.41 m/s(2)) having a carrier frequency of 26 Hz (i.e. engine firing frequency) and modulation frequency of 6.5 Hz (half-order engine harmonic). Evaluations of seven levels of modulation depth parameter m (0.0, 0.1, 0.2, 0.4, 0.6, 0.8, and 1.0) were performed in order to define the growth function of human perceived disturbance as a function of amplitude modulation depth. Two semantic descriptors were used (unpleasantness and roughness) and two test methods (the Thurstone paired-comparison method and the Borg CR-10 direct evaluation scale) for a total of four tests. Each test was performed using an independent group of 25 individuals. The results suggest that there is a critical value of modulation depth m = 0.2 below which human subjects do not perceive differences in amplitude modulation and above which the stimulus-response relationship increases monotonically with a power function. The Stevens power exponents suggest that the perceived unpleasantness is non-linearly dependent on modulation depth m with an exponent greater than 1 and that the perceived roughness is dependent with an exponent close to unity
Enhancing the heavy Higgs signal with jet-jet profile cuts
The jet-jet profile, or detailed manner, in which transverse energy and mass
are distributed around the jet-jet system resulting from the hadronic decay of
a boson in the process Higgs at a proton-proton collider energy of
40\tev is carefully examined. Two observables are defined that can be used to
help distinguish the -jet-jet signal from Higgs decay from the
``ordinary'' QCD background arising from the large transverse momentum
production of single bosons plus the associated jets. By making cuts on
these observables, signal to background enhancement factors greater than
can be obtained.Comment: 16 pages, Univ. Florida IFT-93-
Coherent Tunneling of Atoms from Bose-condensed Gases at Finite Temperatures
Tunneling of atoms between two trapped Bose-condensed gases at finite
temperatures is explored using a many-body linear response tunneling formalism
similar to that used in superconductors. To lowest order, the tunneling
currents can be expressed quite generally in terms of the single-particle
Green's functions of the isolated Bose gases. A coherent first-order tunneling
Josephson current between two atomic Bose-condensates is found, in addition to
coherent and dissipative contributions from second-order
condensate-noncondensate and noncondensate-noncondensate tunneling. Our work is
a generalization of Meier and Zwerger, who recently treated tunneling between
uniform atomic Bose gases. We apply our formalism to the analysis of an
out-coupling experiment induced by light wave fields, using a simple
Bogoliubov-Popov quasiparticle approximation for the trapped Bose gas. For
tunneling into the vacuum, we recover the results of Japha, Choi, Burnett and
Band, who recently pointed out the usefulness of studying the spectrum of
out-coupled atoms. In particular, we show that the small tunneling current of
noncondensate atoms from a trapped Bose gas has a broad spectrum of energies,
with a characteristic structure associated with the Bogoliubov quasiparticle
u^2 and v^2 amplitudes.Comment: 26 pages, 5 figures, minor changes, to appear in PR
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