2,719 research outputs found
Decreasing the threat to learning: the impact of gender ratio in clinical skills small groups
Background & Objective: Small-group learning is a popular fundamental teaching strategy in undergraduate medical education (UME). Evidence of women acting as “social vaccines” for their women peers in small groups has been described in engineering, but not in UME. We seek to better understand the impact of smallgroup gender composition on medical student learning.
Methods: Preclinical medical students were surveyed throughout their clinical skills (CS) course. Likert-scale questions measured students’ perception of their simulation encounters as challenging or threatening, and data were used to calculate a challenge-to-threat ratio (CTR). Scores \u3e1 indicated a situation more challenging than threatening, whilesurvey.
Results: Survey response rates ranged from 62.6-78.8%. Average CTRs of firstyear students were higher for men (1.52-1.64, n=62) than women (1.23-1.46, n=71). All CTRs decreased at the start of the second year (0.80-1.40, n=108), but rebounded as student training progressed (1.29-2.36, n=118). Early second-year CS group gender composition did not impact men (similar CTRs ranging 0.83-1.09). However, women reported a disparate CTR across groups with one, two, and three women (0.80, 1.40, and 1.38 , respectively). Late second-year students reported the highest CTRs in groups with gender parity and lowest CTRs in groups with only one female student. Sentiment analysis of open comments shows a gender effect, with more negative sentiments from women.
Conclusions: Women were less confident than their male peers in the early CS small-group learning environment. Less confidence for all students was reported as CS cases progressed in the second-year to an internal medicine focus; however, confidence recovered in the late second year. A significant threat was perceived by the sole woman in a small group, but the presence of 1-2 other women appeared to be protective against this effect on confidence.https://jdc.jefferson.edu/sexandgenderhealth/1024/thumbnail.jp
Bayesian Conditioning, the Reflection Principle, and Quantum Decoherence
The probabilities a Bayesian agent assigns to a set of events typically
change with time, for instance when the agent updates them in the light of new
data. In this paper we address the question of how an agent's probabilities at
different times are constrained by Dutch-book coherence. We review and attempt
to clarify the argument that, although an agent is not forced by coherence to
use the usual Bayesian conditioning rule to update his probabilities, coherence
does require the agent's probabilities to satisfy van Fraassen's [1984]
reflection principle (which entails a related constraint pointed out by
Goldstein [1983]). We then exhibit the specialized assumption needed to recover
Bayesian conditioning from an analogous reflection-style consideration.
Bringing the argument to the context of quantum measurement theory, we show
that "quantum decoherence" can be understood in purely personalist
terms---quantum decoherence (as supposed in a von Neumann chain) is not a
physical process at all, but an application of the reflection principle. From
this point of view, the decoherence theory of Zeh, Zurek, and others as a story
of quantum measurement has the plot turned exactly backward.Comment: 14 pages, written in memory of Itamar Pitowsk
Properties of 125 GeV Higgs boson in non-decoupling MSSM scenarios
Tantalizing hints of the Higgs boson of mass around 125 GeV have been
reported at the LHC. We explore the MSSM parameter space in which the 125 GeV
state is identified as the heavier of the CP even Higgs bosons, and study two
scenarios where the two photon production rate can be significantly larger than
the standard model (SM). In one scenario, is
enhanced by a light stau contribution, while the () rate
stays around the SM rate. In the other scenario, is
suppressed and not only the but also the
() rates should be enhanced. The rate can be
significantly larger or smaller than the SM rate in both scenarios. Other
common features of the scenarios include top quark decays into charged Higgs
boson, single and pair production of all Higgs bosons in collisions at
GeV.Comment: 20 pages, 5 figures, accepted version for publication in JHE
Discovering the composite Higgs through the decay of a heavy fermion
A possible composite nature of the Higgs could be revealed at the early stage
of the LHC, by analyzing the channels where the Higgs is produced from the
decay of a heavy fermion. The Higgs production from a singly-produced heavy
bottom, in particular, proves to be a promising channel. For a value \lambda=3
of the Higgs coupling to a heavy bottom, for example, we find that, considering
a 125 GeV Higgs which decays into a pair of b-quarks, a discovery is possible
at the 8 TeV LHC with 30 fb^{-1} if the heavy bottom is lighter than roughly
530 GeV (while an observation is possible for heavy bottom masses up to 650
GeV). Such a relatively light heavy bottom is realistic in composite Higgs
models of the type considered and, up to now, experimentally allowed. At
\sqrt{s}=14 TeV the LHC sensitivity on the channel increases significantly.
With \lambda=3 a discovery can occur, with 100 fb^{-1}, for heavy bottom masses
up to 1040 GeV. In the case the heavy bottom was as light as 500 GeV, the 14
TeV LHC would be sensitive to the measure of the \lambda\ coupling in basically
the full range \lambda>1 predicted by the theory.Comment: 25 pp. v2: Minor changes. v3: Version accepted for publication in
JHEP. v4: typos fixe
Interaction Between Convection and Pulsation
This article reviews our current understanding of modelling convection
dynamics in stars. Several semi-analytical time-dependent convection models
have been proposed for pulsating one-dimensional stellar structures with
different formulations for how the convective turbulent velocity field couples
with the global stellar oscillations. In this review we put emphasis on two,
widely used, time-dependent convection formulations for estimating pulsation
properties in one-dimensional stellar models. Applications to pulsating stars
are presented with results for oscillation properties, such as the effects of
convection dynamics on the oscillation frequencies, or the stability of
pulsation modes, in classical pulsators and in stars supporting solar-type
oscillations.Comment: Invited review article for Living Reviews in Solar Physics. 88 pages,
14 figure
Entanglement generation outside a Schwarzschild black hole and the Hawking effect
We examine the Hawking effect by studying the asymptotic entanglement of two
mutually independent two-level atoms placed at a fixed radial distance outside
a Schwarzschild black hole in the framework of open quantum systems. We treat
the two-atom system as an open quantum system in a bath of fluctuating
quantized massless scalar fields in vacuum and calculate the concurrence, a
measurement of entanglement, of the equilibrium state of the system at large
times, for the Unruh, Hartle-Hawking and Boulware vacua respectively. We find,
for all three vacuum cases, that the atoms turn out to be entangled even if
they are initially in a separable state as long as the system is not placed
right at the even horizon. Remarkably, only in the Unruh vacuum, will the
asymptotic entanglement be affected by the backscattering of the thermal
radiation off the space-time curvature. The effect of the back scatterings on
the asymptotic entanglement cancels in the Hartle-Hawking vacuum case.Comment: 15 pages, no figures, Revte
Expression of a barley cystatin gene in maize enhances resistance against phytophagous mites by altering their cysteine-proteases
Phytocystatins are inhibitors of cysteine-proteases from plants putatively involved in plant defence based on their capability of inhibit heterologous enzymes. We have previously characterised the whole cystatin gene family members from barley (HvCPI-1 to HvCPI-13). The aim of this study was to assess the effects of barley cystatins on two phytophagous spider mites, Tetranychus urticae and Brevipalpus chilensis. The determination of proteolytic activity profile in both mite species showed the presence of the cysteine-proteases, putative targets of cystatins, among other enzymatic activities. All barley cystatins, except HvCPI-1 and HvCPI-7, inhibited in vitro mite cathepsin L- and/or cathepsin B-like activities, HvCPI-6 being the strongest inhibitor for both mite species. Transgenic maize plants expressing HvCPI-6 protein were generated and the functional integrity of the cystatin transgene was confirmed by in vitro inhibitory effect observed against T. urticae and B. chilensis protein extracts. Feeding experiments impaired on transgenic lines performed with T. urticae impaired mite development and reproductive performance. Besides, a significant reduction of cathepsin L-like and/or cathepsin B-like activities was observed when the spider mite fed on maize plants expressing HvCPI-6 cystatin. These findings reveal the potential of barley cystatins as acaricide proteins to protect plants against two important mite pests
Human Bocavirus NS1 and NS1-70 Proteins Inhibit TNF-α-Mediated Activation of NF-κB by targeting p65.
Human bocavirus (HBoV), a parvovirus, is a single-stranded DNA etiologic agent causing lower respiratory tract infections in young children worldwide. Nuclear factor kappa B (NF-κB) transcription factors play crucial roles in clearance of invading viruses through activation of many physiological processes. Previous investigation showed that HBoV infection could significantly upregulate the level of TNF-α which is a strong NF-κB stimulator. Here we investigated whether HBoV proteins modulate TNF-α-mediated activation of the NF-κB signaling pathway. We showed that HBoV NS1 and NS1-70 proteins blocked NF-κB activation in response to TNF-α. Overexpression of TNF receptor-associated factor 2 (TRAF2)-, IκB kinase alpha (IKKα)-, IκB kinase beta (IKKβ)-, constitutively active mutant of IKKβ (IKKβ SS/EE)-, or p65-induced NF-κB activation was inhibited by NS1 and NS1-70. Furthermore, NS1 and NS1-70 didn't interfere with TNF-α-mediated IκBα phosphorylation and degradation, nor p65 nuclear translocation. Coimmunoprecipitation assays confirmed the interaction of both NS1 and NS1-70 with p65. Of note, NS1 but not NS1-70 inhibited TNF-α-mediated p65 phosphorylation at ser536. Our findings together indicate that HBoV NS1 and NS1-70 inhibit NF-κB activation. This is the first time that HBoV has been shown to inhibit NF-κB activation, revealing a potential immune-evasion mechanism that is likely important for HBoV pathogenesis
Asteroseismology and Interferometry
Asteroseismology provides us with a unique opportunity to improve our
understanding of stellar structure and evolution. Recent developments,
including the first systematic studies of solar-like pulsators, have boosted
the impact of this field of research within Astrophysics and have led to a
significant increase in the size of the research community. In the present
paper we start by reviewing the basic observational and theoretical properties
of classical and solar-like pulsators and present results from some of the most
recent and outstanding studies of these stars. We centre our review on those
classes of pulsators for which interferometric studies are expected to provide
a significant input. We discuss current limitations to asteroseismic studies,
including difficulties in mode identification and in the accurate determination
of global parameters of pulsating stars, and, after a brief review of those
aspects of interferometry that are most relevant in this context, anticipate
how interferometric observations may contribute to overcome these limitations.
Moreover, we present results of recent pilot studies of pulsating stars
involving both asteroseismic and interferometric constraints and look into the
future, summarizing ongoing efforts concerning the development of future
instruments and satellite missions which are expected to have an impact in this
field of research.Comment: Version as published in The Astronomy and Astrophysics Review, Volume
14, Issue 3-4, pp. 217-36
Top Partner Discovery in the channel at the LHC
In this paper we study the discovery potential of the LHC run II for heavy
vector-like top quarks in the decay channel to a top and a boson. Despite
the usually smaller branching ratio compared to charged-current decays, this
channel is rather clean and allows for a complete mass reconstruction of the
heavy top. The latter is achieved in the leptonic decay channel of the
boson and in the fully hadronic top channel using boosted jet and jet
substructure techniques. To be as model-independent as possible, a simplified
model approach with only two free parameters has been applied. The results are
presented in terms of parameter space regions for evidence or
discovery for such new states in that channel.Comment: 24 pages, 8 figures, version 2 updated to JHEP 01 (2015) 08
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