6,911 research outputs found
The challenges and issues of undergraduate student retention and attainment in UK veterinary medical education
Student retention and attainment has recently been identified as a key area for development in veterinary medical education enquiry. Woodfield's research on retention and attainment across the UK disciplines has yielded some unique information about the challenges and issues of students who study veterinary medicine and related subjects. The present literature review aims to expand on Woodfield's findings and explain important issues about retention and attainment across veterinary medicine. Overall, the subject of retention and attainment in undergraduate veterinary medical education needs a great deal more empirical attention, such as data on the retention and attainment of mature and widening access students, and the effects of students being placed at remote locations during their studies. Our findings also cover some unsurprising issues: the dominance of women in a profession that is principally lead by men, the underrepresentation of black and minority ethnic (BME) students in veterinary medicine, and the effects of content overload in the veterinary medical curriculum. Based on data gathered by Woodfield and our investigation of the scholarly and gray literatures, we offer an overview of gaps in current knowledge and recommendations for further research
Identity, environment and mental wellbeing in the veterinary profession
Mental health and career dissatisfaction are of increasing concern to the veterinary profession. The influence of identity on the psychological wellbeing of veterinarians has not been widely explored. Twelve recent veterinary graduates were enrolled in a private social media discussion group, and their identities investigated through narrative inquiry: a methodology which enables identity priorities to be extrapolated from stories of experience. Two distinct variants of the veterinary identity were identified: an academic, ‘diagnosis-focused’ identity, which prioritised definitive diagnosis and best-evidence treatment; and a broader ‘challenge-focused’ identity, where priorities additionally included engaging with the client, challenging environment or veterinary business. Contextual challenges (such as a client with limited finances or difficult interpersonal interactions) were seen as a source of frustration for those with a diagnosis-focused identity, as they obstructed the realisation of identity goals. Overcoming these challenges provided satisfaction to those with a challenge-focused identity. The employment environment of the graduates (general veterinary practice) provided more opportunities for those with a challenge-focused identity to realise identity goals, and more markers of emotional wellbeing were apparent in their stories. Markers of poor emotional health were evident in the stories of those with a diagnosis-focused identity
Massive planet migration: Theoretical predictions and comparison with observations
We quantify the utility of large radial velocity surveys for constraining
theoretical models of Type II migration and protoplanetary disk physics. We
describe a theoretical model for the expected radial distribution of extrasolar
planets that combines an analytic description of migration with an empirically
calibrated disk model. The disk model includes viscous evolution and mass loss
via photoevaporation. Comparing the predicted distribution to a uniformly
selected subsample of planets from the Lick / Keck / AAT planet search
programs, we find that a simple model in which planets form in the outer disk
at a uniform rate, migrate inward according to a standard Type II prescription,
and become stranded when the gas disk is dispersed, is consistent with the
radial distribution of planets for orbital radii 0.1 AU < a < 2.5 AU and planet
masses greater than 1.65 Jupiter masses. Some variant models are disfavored by
existing data, but the significance is limited (~95%) due to the small sample
of planets suitable for statistical analysis. We show that the favored model
predicts that the planetary mass function should be almost independent of
orbital radius at distances where migration dominates the massive planet
population. We also study how the radial distribution of planets depends upon
the adopted disk model. We find that the distribution can constrain not only
changes in the power-law index of the disk viscosity, but also sharp jumps in
the efficiency of angular momentum transport that might occur at small radii.Comment: ApJ, in press. References updated to match published versio
Resonant state expansion applied to planar waveguides
The resonant state expansion, a recently developed method in electrodynamics,
is generalized here to planar open optical systems with non-normal incidence of
light. The method is illustrated and verified on exactly solvable examples,
such as a dielectric slab and a Bragg reflector microcavity, for which explicit
analytic formulas are developed. This comparison demonstrates the accuracy and
convergence of the method. Interestingly, the spectral analysis of a dielectric
slab in terms of resonant states reveals an influence of waveguide modes in the
transmission. These modes, which on resonance do not couple to external light,
surprisingly do couple to external light for off-resonant excitation
The interplay between X-ray photoevaporation and planet formation
We assess the potential of planet formation instigating the early formation
of a photoevaporation driven gap, up to radii larger than typical for
photoevaporation alone. For our investigation we make use of hydrodynamics
models of photoevaporating discs with a giant planet embedded. We find that, by
reducing the mass accretion flow onto the star, discs that form giant planets
will be dispersed at earlier times than discs without planets by X-ray
photoevaporation. By clearing the portion of the disc inner of the planet
orbital radius, planet formation induced photoevaporation (PIPE) is able to
produce transition disc that for a given mass accretion rate have larger holes
when compared to standard X-ray photoevaporation. This constitutes a possible
route for the formation of the observed class of accreting transition discs
with large holes, which are otherwise difficult to explain by planet formation
or photoevaporation alone. Moreover, assuming that a planet is able to filter
dust completely, PIPE produces a transition disc with a large hole and may
provide a mechanism to quickly shut down accretion. This process appears to be
too slow however to explain the observed desert in the population of transition
disc with large holes and low mass accretion rates.Comment: 11 pages, 10 figures, accepted by MNRAS on 31/12/201
Magnetically modulated accretion in T Tauri stars
We examine how accretion on to T Tauri stars may be modulated by a
time-dependent `magnetic gate' where the inner edge of the accretion disc is
disrupted by a varying stellar field. We show that magnetic field variations on
time-scales shorter than 10^5 yr can modulate the accretion flow, thus
providing a possible mechanism both for the marked photometric variability of T
Tauri stars and for the possible conversion of T Tauri stars between classical
and weak line status. We thus suggest that archival data relating to the
spectrophotometric variability of T Tauri stars may provide an indirect record
of magnetic activity cycles in low-mass pre-main-sequence stars.Comment: LaTeX file (requires mn.sty), 4 pages, no figures or tables. To
appear in MNRAS
Feedback control architecture & the bacterial chemotaxis network
Bacteria move towards favourable and away from toxic environments by changing their swimming pattern. This response is regulated by the chemotaxis signalling pathway, which has an important feature: it uses feedback to ‘reset’ (adapt) the bacterial sensing ability, which allows the bacteria to sense a range of background environmental changes. The role of this feedback has been studied extensively in the simple chemotaxis pathway of Escherichia coli. However it has been recently found that the majority of bacteria have multiple chemotaxis homologues of the E. coli proteins, resulting in more complex pathways. In this paper we investigate the configuration and role of feedback in Rhodobacter sphaeroides, a bacterium containing multiple homologues of the chemotaxis proteins found in E. coli. Multiple proteins could produce different possible feedback configurations, each having different chemotactic performance qualities and levels of robustness to variations and uncertainties in biological parameters and to intracellular noise. We develop four models corresponding to different feedback configurations. Using a series of carefully designed experiments we discriminate between these models and invalidate three of them. When these models are examined in terms of robustness to noise and parametric uncertainties, we find that the non-invalidated model is superior to the others. Moreover, it has a ‘cascade control’ feedback architecture which is used extensively in engineering to improve system performance, including robustness. Given that the majority of bacteria are known to have multiple chemotaxis pathways, in this paper we show that some feedback architectures allow them to have better performance than others. In particular, cascade control may be an important feature in achieving robust functionality in more complex signalling pathways and in improving their performance
Mirror-Image Stimulation Applied to Field Behavioral Studies
This is the publisher's version, also available electronically from http://www.jstor.org/stable/info/1935349Twenty-nine adult and yearling marmots were exposed to mirror-image stimulation. Marmots interacted intensely with their image, and the frequency of occuranaces of 22 behaviors was recorded. The four factors extracted from the behavioral data by factor analysis accounted for 88% of the total variance. Three factors were interpretable and designated "approach," "avoidance," and "sociability." Behavioral patterns were stable over time and repeatable. A plot of "avoidance" against "sociability" provides a visualization of the numerical behavioral profile of each animal which is consistent with the interpretable in terms of behavioral patterns observed in the field
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