10,248 research outputs found
Is it time for integration of surgical skills simulation into the United Kingdom undergraduate medical curriculum? A perspective from King’s College London School of Medicine
PURPOSE: Changes in undergraduate medical curricula, combined with reforms in postgraduate education, have training implications for surgical skills acquisition in a climate of reduced clinical exposure. Confidence and prior experience influences the educational impact of learning. Currently there is no basic surgical skills (BSS) programme integrated into undergraduate curricula in the United Kingdom. We explored the role of a dedicated BSS programme for undergraduates in improving confidence and influencing careers in King's College London School of Medicine, and the programme was evaluated. METHODS: A programme was designed in-line with the established Royal College of Surgeons course. Undergraduates were taught four key skills over four weeks: knot-tying, basic-suturing, tying-at-depth and chest-drain insertion, using low-fidelity bench-top models. A Likert-style questionnaire was designed to determine educational value and influence on career choice. Qualitative data was collected. RESULTS: Only 29% and 42% of students had undertaken previous practice in knot-tying and basic suturing, respectively. 96% agreed that skills exposure prior to starting surgical rotations was essential and felt a dedicated course would augment undergraduate training. There was a significant increase in confidence in the practice and knowledge of all skills taught (p<0.01), with a greater motivation to be actively involved in the surgical firm and theatres. CONCLUSION: A simple, structured BSS programme can increase the confidence and motivation of students. Early surgical skills targeting is valuable for students entering surgical, related allied, and even traditionally non-surgical specialties such as general practice. Such experience can increase the confidence of future junior doctors and trainees. We advocate the introduction of a BSS programme into United Kingdom undergraduate curricula
Internal Migration and Regional Population Dynamics in Europe: Estonia Case Study
Estonia has experienced a long-lasting and strong influence of international migration on regional population growth. Post-war immigrants account for about 36 per cent of the total population, and are concentrated in larger cities of Northern Estonia. Regionally, the relative proportions of the native-born and immigrant origin sub-populations are important for the understanding of population change and internal migration flows in the 1980-1990s.
In Estonia, the quality of migration data requires careful assessment. The preservation of Soviet-type record-keeping has reduced data quality in the 1990s, already low, and use of the data should keep data quality problems in mind. Otherwise, false conclusions can be reached.
To describe internal migration patterns, it has proved technically feasible and very useful to disaggregate the county population into rural and urban components, and correspondingly, the migration flows into four directions (urban-urban, urban-rural, rural-urban and rural-rural).
During the 1980s the pattern of population growth and internal migration has changed in Estonia. Reflecting the turnaround in long-term population processes, migration development reached the advanced stage with more or less regionally balanced in- and out-migration flows and decreasing importance of net migration. Accordingly, to understand current trends and patterns, explanations must be sought from the 1980s which has served a starting point for the present trends rather than from the period of economic transition in the 1990s.
As a part of the turnaround, the century-long persistent rural depopulation has come to an end and the moderate growth has started reflecting natural population increase as well as deurbanization. In the 1980s two developments have occurred in parallel: migratory increase of rural population led by a deurbanizing native-born population, and continued urban population growth as a result of the population momentum of pre-transition immigrants. In future decades, the urban deconcentration will probably be the underlying trend in Estonia. In Estonia, noticeable proportion of territory and population is located in islands. However, the island population does not show any systematic difference in the type of internal migration. Particularly, the depopulation of island populations, observed in several comparable European cases, is not occurring.
Each life-course stage was found to have its specific migration pattern, more stable than the pattern for the total population. In many cases the changes of internal migration are determined by the change in the proportion of population in different life-course stages. Additionally, the life-course approach has been useful in demonstrating the features of the present Estonian internal migration pattern which appear closer to the countries of comparable in demographic development, more or less regardless of the significant differences in the level of economic development. Among life-course groups, in Estonia the older working age population was characterized by the strongest deurbanization intensities in 1995. The same group has also undergone the largest modification of migration pattern during the economic transition (1987-1995)
Nonlinear ion waves in Fermi-Dirac pair plasmas
Arbitrary amplitude nonlinear ion waves is investigated in an extremely
degenerate electron-positron-ion plasma with relativistic electrons/positrons
and dynamic cold ions using Sagdeev pseudo-potential method in framework of
quantum hydrodynamics model. The matching criteria of existence for ion
solitary as well as periodic nonlinear excitations is studied numerically in
terms of the relativistic degeneracy parameter, relative positron concentration
and the relativistic normalized propagation-speed range of these waves are
obtained. It is remarked that the electron relativistic degeneracy and relative
positron concentration in such plasmas have significant effects on nonlinear
wave propagations in relativistically degenerate Fermi-Dirac plasma. Our
results are in good agreement with the previously reported ones obtained using
semiclassical Thomas-Fermi approximation in dense plasmas with non-relativistic
and ultra-relativistic electrons and positrons. Current findings can be
appropriate for the study of astrophysical superdense compact objects such as
white dwarfs.Comment: Published in Physics of Plasma
Gravitational Lens Statistics and The Density Profile of Dark Halos
We investigate the influence of the inner profile of lens objects on
gravitational lens statistics taking into account of the effect of
magnification bias and both the evolution and the scatter of halo profiles. We
take the dark halos as the lens objects and consider the following three models
for the density profile of dark halos; SIS (singular isothermal sphere), the
NFW (Navarro Frenk White) profile, and the generalized NFW profile which has a
different slope at smaller radii. The mass function of dark halos is assumed to
be given by the Press-Schechter function. We find that magnification bias for
the NFW profile is order of magnitude larger than that for SIS. We estimate the
sensitivity of the lensing probability of distant sources to the inner profile
of lenses and to the cosmological parameters. It turns out that the lensing
probability is strongly dependent on the inner density profile as well as on
the cosmological constant. We compare the predictions with the largest
observational sample, the Cosmic Lens All-Sky Survey. The absence or presence
of large splitting events in larger surveys currently underway such as the 2dF
and SDSS could set constraints on the inner density profile of dark halos.Comment: 22 pages, minor changes and references added, accepted for
publication in Ap
The influence of spontaneous activity on stimulus processing in primary visual cortex
Spontaneous activity in the resting human brain has been studied extensively; however, how such activity affects the local processing of a sensory stimulus is relatively unknown. Here, we examined the impact of spontaneous activity in primary visual cortex on neuronal and behavioural responses to a simple visual stimulus, using functional MRI. Stimulus-evoked responses remained essentially unchanged by spontaneous fluctuations, combining with them in a largely linear fashion (i.e., with little evidence for an interaction). However, interactions between spontaneous fluctuations and stimulus-evoked responses were evident behaviourally: high levels of spontaneous activity tended to be associated with increased stimulus detection at perceptual threshold. Our results extend those found in studies of spontaneous fluctuations in motor cortex and higher order visual areas, and suggest a fundamental role for spontaneous activity in stimulus processing. (C) 2011 Elsevier Inc. All rights reserved
Dynamic black holes through gravitational collapse: Analysis of multipole moment of the curvatures on the horizon
We have investigated several properties of rapidly rotating dynamic black
holes generated by gravitational collapse of rotating relativistic stars. At
present, numerical simulations of the binary black hole merger are able to
produce a Kerr black hole of J_final / M_final^2 up to = 0.91, of gravitational
collapse from uniformly rotating stars up to J_final / M_final^2 ~ 0.75, where
J_final is the total angular momentum and M_final the total gravitational mass
of the hole. We have succeeded in producing a dynamic black hole of spin
J_final / M_final^2 ~ 0.95 through the collapse of differentially rotating
relativistic stars. We have investigated those dynamic properties through
diagnosing multipole moment of the horizon, and found the following two
features. Firstly, two different definitions of the angular momentum of the
hole, the approximated Killing vector approach and dipole moment of the current
multipole approach, make no significant difference to our computational
results. Secondly, dynamic hole approaches a Kerr by gravitational radiation
within the order of a rotational period of an equilibrium star, although the
dynamic hole at the very forming stage deviates quite far from a Kerr. We have
also discussed a new phase of quasi-periodic waves in the gravitational
waveform after the ringdown in terms of multipole moment of the dynamic hole.Comment: 13 pages with 19 figures, revtex4-1.cls. Accepted for publication in
the Physical Review
Topological regluing of rational functions
Regluing is a topological operation that helps to construct topological
models for rational functions on the boundaries of certain hyperbolic
components. It also has a holomorphic interpretation, with the flavor of
infinite dimensional Thurston--Teichm\"uller theory. We will discuss a
topological theory of regluing, and trace a direction in which a holomorphic
theory can develop.Comment: 38 page
X-ray Polarization Signatures of Compton Scattering in Magnetic Cataclysmic Variables
Compton scattering within the accretion column of magnetic cataclysmic
variables (mCVs) can induce a net polarization in the X-ray emission. We
investigate this process using Monte Carlo simulations and find that
significant polarization can arise as a result of the stratified flow structure
in the shock-ionized column. We find that the degree of linear polarization can
reach levels up to ~8% for systems with high accretion rates and low
white-dwarf masses, when viewed at large inclination angles with respect to the
accretion column axis. These levels are substantially higher than previously
predicted estimates using an accretion column model with uniform density and
temperature. We also find that for systems with a relatively low-mass white
dwarf accreting at a high accretion rate, the polarization properties may be
insensitive to the magnetic field, since most of the scattering occurs at the
base of the accretion column where the density structure is determined mainly
by bremsstrahlung cooling instead of cyclotron cooling.Comment: 7 pages, 8 figures, accepted by MNRA
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