95,679 research outputs found
Associations between family weight-based teasing, eating pathology, and psychosocial functioning among adolescent military dependents
Weight-based teasing (WBT) by family members is commonly reported among youth and is associated with eating and mood-related psychopathology. Military dependents may be particularly vulnerable to family WBT and its sequelae due to factors associated with their parents\u27 careers, such as weight and fitness standards and an emphasis on maintaining one\u27s military appearance; however, no studies to date have examined family WBT and its associations within this population. Therefore, adolescent military dependents at-risk for adult obesity and binge-eating disorder were studied prior to entry in a weight gain prevention trial. Youth completed items from the Weight-Based Victimization Scale (to assess WBT by parents and/or siblings) and measures of psychosocial functioning, including the Beck Depression Inventory-II, The Rosenberg Self-Esteem Scale, and the Social Adjustment Scale. Eating pathology was assessed via the Eating Disorder Examination interview, and height and fasting weight were measured to calculate BM
An automated classification approach to ranking photospheric proxies of magnetic energy build-up
We study the photospheric magnetic field of ~2000 active regions in solar
cycle 23 to search for parameters indicative of energy build-up and subsequent
release as a solar flare. We extract three sets of parameters: snapshots in
space and time- total flux, magnetic gradients, and neutral lines; evolution in
time- flux evolution; structures at multiple size scales- wavelet analysis.
This combines pattern recognition and classification techniques via a relevance
vector machine to determine whether a region will flare. We consider
classification performance using all 38 extracted features and several feature
subsets. Classification performance is quantified using both the true positive
rate and the true negative rate. Additionally, we compute the true skill score
which provides an equal weighting to true positive rate and true negative rate
and the Heidke skill score to allow comparison to other flare forecasting work.
We obtain a true skill score of ~0.5 for any predictive time window in the
range 2-24hr, with a TPR of ~0.8 and a TNR of ~0.7. These values do not appear
to depend on the time window, although the Heidke skill score (<0.5) does.
Features relating to snapshots of the distribution of magnetic gradients show
the best predictive ability over all predictive time windows. Other
gradient-related features and the instantaneous power at various wavelet scales
also feature in the top five ranked features in predictive power. While the
photospheric magnetic field governs the coronal non-potentiality (and
likelihood of flaring), photospheric magnetic field alone is not sufficient to
determine this uniquely. Furthermore we are only measuring proxies of the
magnetic energy build up. We still lack observational details on why energy is
released at any particular point in time. We may have discovered the natural
limit of the accuracy of flare predictions from these large scale studies
Improving and sustaining quality of child health care through IMCI training and supervision: experience from rural Bangladesh
CAUL read and publish agreementfals
Combustion Modeling of Gasoline Two-stroke Linear Engine by the Modified Weibe Function
This paper presents the mathematical modeling of combustion in a two-strokelinear combustion engine incorporating combustion and kickbackchambers. A thermodynamics simulation is performed using a Weibeflrnction that applied to linear engine. The computer program isdeveloped to compute the instantaneous velocity and temperature in thecombustion chamber. The fuel is gasoline and the cylinder bore sizes tobe considered are of 50mm and 76mm. From the computation, theresults show that the peak temperatures are 870 K and 995 K, the meanvelocities during expansion are 3.8m/s and 5m/s, the mean velocitiesduring compression 2.9m/s and 4.4m/s, respectively
Stabilisation of BGK modes by relativistic effects
Context. We examine plasma thermalisation processes in the foreshock region of astrophysical shocks within a fully kinetic and self-consistent treatment. We concentrate on proton beam driven electrostatic processes, which are thought to play a key role in the beam relaxation and the particle acceleration. Our results have implications for the effectiveness of electron surfing acceleration and
the creation of the required energetic seed population for first order Fermi acceleration at the shock front.
Aims. We investigate the acceleration of electrons via their interaction with electrostatic waves, driven by the relativistic Buneman instability, in a system dominated by counter-propagating proton beams.
Methods. We adopt a kinetic Vlasov-Poisson description of the plasma on a fixed Eulerian grid and observe the growth and saturation of electrostatic waves for a range of proton beam velocities, from 0.15c to 0.9c.
Results. We can report a reduced stability of the electrostatic wave (ESW) with increasing non-relativistic beam velocities and an improved wave stability for increasing relativistic beam velocities, both in accordance with previous findings. At the highest beam speeds, we find the system to be stable again for a period of ≈160 plasma periods. Furthermore, the high phase space resolution
of the Eulerian Vlasov approach reveals processes that could not be seen previously with PIC simulations. We observe a, to our knowledge, previously unreported secondary electron acceleration mechanism at low beam speeds. We believe that it is the result of parametric couplings to produce high phase velocity ESW’s which then trap electrons, accelerating them to higher energies. This
allows electrons in our simulation study to achieve the injection energy required for Fermi acceleration, for beam speeds as low as 0.15c in unmagnetised plasma
Projection optics for extreme ultraviolet lithography (EUVL) micro-field exposure tools (METs) with a numerical aperture of 0.5
Abstract not provide
Lessons from crossing symmetry at large N
20 pages, v2: Assumptions stated more clearly, version published in JHEPWe consider the four-point correlator of the stress tensor multiplet in N=4 SYM. We construct all solutions consistent with crossing symmetry in the limit of large central charge c ~ N^2 and large g^2 N. While we find an infinite tower of solutions, we argue most of them are suppressed by an extra scale \Delta_{gap} and are consistent with the upper bounds for the scaling dimension of unprotected operators observed in the numerical superconformal bootstrap at large central charge. These solutions organize as a double expansion in 1/c and 1/\Delta_{gap}. Our solutions are valid to leading order in 1/c and to all orders in 1/\Delta_{gap} and reproduce, in particular, instanton corrections previously found. Furthermore, we find a connection between such upper bounds and positivity constraints arising from causality in flat space. Finally, we show that certain relations derived from causality constraints for scattering in AdS follow from crossing symmetry.Peer reviewe
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