57,377 research outputs found
A Grid of Relativistic, non-LTE Accretion Disk Models for Spectral Fitting of Black Hole Binaries
Self-consistent vertical structure models together with non-LTE radiative
transfer should produce spectra from accretion disks around black holes which
differ from multitemperature blackbodies at levels which may be observed. High
resolution, high signal-to-noise observations warrant spectral modeling which
both accounts for relativistic effects, and treats the physics of radiative
transfer in detail. In Davis et al. (2005) we presented spectral models which
accounted for non-LTE effects, Compton scattering, and the opacities due to
ions of abundant metals. Using a modification of this method, we have tabulated
spectra for black hole masses typical of Galactic binaries. We make them
publicly available for spectral fitting as an Xspec model. These models
represent the most complete realization of standard accretion disk theory to
date. Thus, they are well suited for both testing the theory's applicability to
observed systems and for constraining properties of the black holes, including
their spins.Comment: 7 pages, emulate ApJ, accepted to Ap
Ability Versus Trait Emotional Intelligence: Dual Influences on Adolescent Psychological Adaptation
Emotional intelligence (EI) is reliably associated with better mental health. A growing body of evidence suggests that EI acts as a protective buffer against some psychosocial stressors to promote adaptation. However, little is known about how the two principle forms of EI (trait and ability) work together to impact underlying stressor-health processes in adolescence. One thousand one hundred and seventy British adolescents (mean age = 13.03 years; SD = 1.26) completed a variety of standardized instruments assessing EI; coping styles; family dysfunction; negative life events; socioeconomic adversity; depression and disruptive behavior. Path analyses found that trait and ability EI work in tandem to modify the selection and efficacy of avoidant coping to influence the indirect effect of stressors on depression but not disruptive behavior. Nevertheless, actual emotional skill (ability EI) appears dependent on perceived competency (trait EI) to realize advantageous outcomes. Findings are evaluated and discussed with reference to theoretical and practical implications
FearNot! An Anti-Bullying Intervention: Evaluation of an Interactive Virtual Learning Environment
Original paper can be found at: http://www.aisb.org.uk/publications/proceedings.shtm
Do Solar Neutrino Experiments Imply New Physics?
None of the 1000 solar models in a full Monte Carlo simulation is consistent
with the results of the chlorine or the Kamiokande experiments. Even if the
solar models are forced artifically to have a \b8 neutrino flux in agreeement
with the Kamiokande experiment, none of the fudged models agrees with the
chlorine observations. The GALLEX and SAGE experiments, which currently have
large statistical uncertainties, differ from the predictions of the standard
solar model by and , respectively.Comment: 7 pages (figures not included), Institute for Advanced Study number
AST 92/51. For a hard copy with the figures, write: [email protected]
Reducing Global Warming and Adapting to Climate Change: The Potential of Organic Agriculture
Climate change mitigation is urgent and adaptation to climate change is crucial, particularly in agriculture, where food security is at stake. Agriculture, currently responsible for 20-30% of global greenhouse gas emissions counting direct and indirect agricultural emissions), can however contribute to both climate change mitigation and adaptation. The main mitigation potential lies in the capacity of agricultural soils to sequester CO2 through building organic matter. This potential can be realized by employing sustainable agricultural practices, such as those commonly found within organic farming systems. Examples of these practices are the use of organic fertilizers and crop rotations including legumes leys and cover crops. Mitigation is also achieved in organic agriculture through the avoidance of open biomass burning and the avoidance of synthetic fertilizers and the related production emissions from fossil fuels. Common organic practices also contribute to adaptation. Building soil organic matter increases water retention capacity, and creates more stabile, fertile soils, thus reducing vulnerability to drought, extreme precipitation events, floods and water logging. Adaptation is further supported by increased agro-ecosystem diversity of organic farms, due to reduced nitrogen inputs and the absence of chemical pesticides. The high diversity together with the lower input costs of organic agriculture is key in reducing production risks associated with extreme weather events. All these advantageous practices are not exclusive to organic agriculture. However, they are core parts of the organic production system, in contrast to most non-organic agriculture, where they play a minor role only.
Mitigation in agriculture cannot be restricted to the agricultural sector alone, though. Consumer behaviour strongly influences agricultural production systems, and thus their mitigation potential. Significant factors are meat consumption and food wastage. Any discussion on mitigation climate change in agriculture needs to address the entire food chain and needs to be linked to general sustainable development strategies.
The main challenges to climate change mitigation and adaptation in organic agriculture and agriculture in general concern
a)the understanding of some of the basic processes, such as the interaction of N2O emissions and soil carbon sequestration, contributions of roots to soil carbon sequestration and the life-cycle emissions of organic fertilizers such as compost;
b) approaches for emissions accounting that adequately represent agricultural production systems with multiple and diverse outputs and that also encompass ecosystem services;
c) the identification and implementation of most adequate policy frameworks for supporting mitigation and adaptation in agriculture, i.e: not putting systemic approaches at a disadvantage due to difficulties in the quantification of emissions, and in their allocation to single products;
d) how to assure that the current focus on mitigation does not lead to neglect of the other sustainability aspects of agriculture, such as pesticide loads, eutrophication, acidification or soil erosion and
e) the question how to address consumer behaviour and how to utilize the mitigation potential of changes in consumption patterns
Anisotropic charge transport in non-polar GaN QW: polarization induced charge and interface roughness scattering
Charge transport in GaN quantum well (QW) devices grown in non-polar
direction has been theoretically investigated . Emergence of anisotropic line
charge scattering mechanism originating as a result of anisotropic rough
surface morphology in conjunction with in-plane built-in polarization has been
proposed. It has shown that in-plane growth anisotropy leads to large
anisotropic carrier transport at low temperatures. At high temperatures, this
anisotropy in charge transport is partially washed out by strong isotropic
optical phonon scattering in GaN QW.Comment: 4 pages, 4 figure
Classical field techniques for condensates in one-dimensional rings at finite temperatures
For a condensate in a one-dimensional ring geometry, we compare the
thermodynamic properties of three conceptually different classical field
techniques: stochastic dynamics, microcanonical molecular dynamics, and the
classical field method. Starting from non-equilibrium initial conditions, all
three methods approach steady states whose distribution and correlation
functions are in excellent agreement with an exact evaluation of the partition
function in the high-temperature limit. Our study helps to establish these
various classical field techniques as powerful non-perturbative tools for
systems at finite temperatures.Comment: 7 pages, 7 figures; minor changes, one reference adde
KINEMATICS OF BOARD BREAKING IN KARATE USING VIDEO ANALYSIS – A DYNAMIC MODEL OF APPLIED PHYSICS AND HUMAN PERFORMANCE
Martial arts have fascinated the world with its fast paced actions andamazing feats. In this study the kinematics of a karate straight punch hasbeen studied through slow motion video analysis in relation to momentum,velocity, acceleration and impact of force as a function of time to enhancethe execution of the karate straight punch. It has been found that the impulsewas significantly smaller when the board is broken.From an educational perspective, this analysis will help in integrating somevalid concepts of physics in teaching mechanical concepts of movements insports. This quantitative analysis will enable the students to understand themovement technique to avoid the injuries. It will be helpful in devisingtraining schedule for karate students and in teaching them karate skills inproper manner. A person, regardless of size and strength, if trained properlyin the terms of body mechanics, kinematics, and physics of martial arts, canput out optimum performance and derive maximum benefits withoutunnecessary wastage of energy. The subjects had also completed theConcentration Grid to find out their concentration levels. The karateka whowas successful in breaking the board has been found to have a higher level ofconcentration as compared to the unsuccessful karateka, indicating that thispsychological parameter also has significant impact on the impulse leadingto board breaking karate performance
Recommended from our members
The effect of consumption volume on profile and liking of oral nutritional supplements of varied sweetness: sequential profiling and boredom tests
Oral nutrition supplements (ONS) are routinely prescribed to those with, or at risk of, malnutrition. Previous research identified poor compliance due to taste and sweetness. This paper investigates taste and hedonic liking of ONS, of varying sweetness and metallic levels, over consumption volume; an important consideration as patients are prescribed large volumes of ONS daily. A sequential descriptive profile was developed to determine the perception of sensory attributes over repeat consumption of ONS. Changes in liking of ONS following repeat consumption were characterised by a boredom test. Certain flavour (metallic taste, soya milk flavour) and mouthfeel (mouthdrying, mouthcoating) attributes built up over increased consumption volume (p 0.002). Hedonic liking data from two cohorts, healthy older volunteers (n = 32, median age 73) and patients (n = 28, median age 85), suggested such build-up was disliked. Efforts made to improve the palatability of ONS must take account of the build up of taste and mouthfeel characteristics over increased consumption volume
- …