2,622 research outputs found
Gravitomagnetic Resonance Shift due to a Slowly Rotating Compact Star
The effect of a slowly rotating mass on a forced harmonic oscillator with two
degrees of freedom is studied in the weak field approximation. It is found that
according to the general theory of relativity there is a shift in the resonat
frequency of the oscillator which depends on the density and rotational
frequency of the gravitational source. The proposed shift is quite small under
normal physical situations however it is estimated that for compact x-ray
sources such as white dwarfs, pulsars, and neutron stars the shift is quite
appreciable.Comment: 8 pages, 2 figures, Accepted for Publication in Inter. Journal of
Modern Physics
Risk perception and emergency experience: comparing a representative German sample with German emergency survivors
People’s perception of risk and its influencing factors has become an important element of research in past decades. The present paper investigated the influence of emergency experiences on risk perception and the impact of experience and gender on the accuracy of risk perception. A representative sample of the German population was subdivided into a general survivor group who had experienced at least one emergency previously (N = 165) and a general public group with no prior emergency experiences (N = 2248), which were compared to a German sample of survivors from the EU-funded Behavior, Security, and Culture (BeSeCu) international study of human behavior in emergency situations and evacuations (N = 201). The perceived risk of different emergencies – including larger-scale events like floods and other important but often overlooked events like domestic fires – was assessed with a questionnaire. Objective risk was also calculated for different emergencies and compared to the risk perceptions of each group to provide a measure of accuracy. The results of this study showed that emergency experiences increase perceived risk, for the experienced event in particular, and this outcome was evident regardless of whether the event was a large-scale one like a natural disaster or a smaller-scale one like a fire in one’s home. Additional data from the BeSeCu survivors identified several pre-, peri-, and post-event factors that might have influenced this outcome. Further results included the finding that gender is an important factor that moderates the accuracy of risk estimations but researchers should be mindful that the presence and pattern of any gender difference in perceived risk accuracy may vary across different types of event. Possible reasons and implications of the results are discussed
Gathering a Family Around the Coffee Machine: The People at the Heart of the Sunderland Cooperative Heritage Lab
Evidence of the Boyer Model of Scholarship in Counselor Education
This study delineated how the Boyer (1990) model of scholarship has been implemented in counselor education. The taxonomy of scholarship was delineated: Scholarship of Discovery, Scholarship of Teaching, Scholarship of Application, and Scholarship of Integration. The Journal of Counseling and Development and Counselor Education and Supervision were examined from 2000 to 2008. Examples of scholarship from each journal were identified. Evidence of the Boyer model in premier counseling journals suggests a consistency of approach between this model and scholarly activities in counselor education. An expanded view of scholarship may have positive implications for scholarly activity in graduate education and pretenured faculty
Emergency department based intervention with adolescent substance users: 10 year economic and health outcomes
BACKGROUND: Alcohol and other drug (AOD) use are significant cause of disease burden and costs among adolescents. METHODS: We conducted a randomized trial in hospital emergency departments (ED) following an AOD-related presentation, comparing usual care with brief advice and referral to link adolescents aged 12-19 years with external AOD services. Subsequently, we used health data linkage to assemble data on mortality, hospital admissions, ED attendances, out-patient mental health and use of opiate pharmacotherapies in the next 10 years. From these, treatment costs and rates of events were estimated and compared using generalized linear models. RESULTS: Those who received the intervention had lower costs (227: z=3.16, p=0.002) and rates (0.03 versus 0.25: z=2.57, p=0.010) of ED mental health AOD presentations. However, the intervention did not significantly reduce overall mean health costs per patient (intervention 64833, p=0.800). Similarly, there was no significant difference in the costs associated with hospitalizations (50911 p=0.924), overall ED presentations (4150, p=0.916), out-patient mental health services (7717, p=0.282), or opiate pharmacotherapies (2054, p=0.209). Injecting drug use was a significant baseline predictor of subsequent costs in the cohort (z=2.64, p=0.008). CONCLUSIONS: An ED delivered intervention may reduce direct ED costs and subsequent ED AOD attendances. There was also some indication that overall costs may be impacted, with economically large but non-significant differences between the groups. The high costs and morbidity incurred by some of this cohort illustrate the importance of targeting high-risk adolescents
Chaos in the Kepler System
The long-term dynamical evolution of a Keplerian binary orbit due to the
emission and absorption of gravitational radiation is investigated. This work
extends our previous results on transient chaos in the planar case to the three
dimensional Kepler system. Specifically, we consider the nonlinear evolution of
the relative orbit due to gravitational radiation damping as well as external
gravitational radiation that is obliquely incident on the initial orbital
plane. The variation of orbital inclination, especially during resonance
capture, turns out to be very sensitive to the initial conditions. Moreover, we
discuss the novel phenomenon of chaotic transition.Comment: RevTeX, 22 pages, 6 figure
Plasma transport in stochastic magnetic field caused by vacuum resonant magnetic perturbations at diverted tokamak edge
An AUC-based Permutation Variable Importance Measure for Random Forests
The random forest (RF) method is a commonly used tool for classification with high dimensional data as well as for ranking candidate predictors based on the so-called random forest variable importance measures (VIMs). However the classification performance of RF is known to be suboptimal in case of strongly unbalanced data, i.e. data where response class sizes differ considerably. Suggestions were made to obtain better classification performance based either on sampling procedures or on cost sensitivity analyses. However to our knowledge the performance of the VIMs has not yet been examined in the case of unbalanced response classes. In this paper we explore the performance of the permutation VIM for unbalanced data settings and introduce an alternative permutation VIM based on the area under the curve (AUC) that is expected to be more robust towards class imbalance. We investigated the performance of the standard permutation VIM and of our novel AUC-based permutation VIM for different class imbalance levels using simulated data and real data. The results suggest that the standard permutation VIM loses its ability to discriminate between associated predictors and predictors not associated with the response for increasing class imbalance. It is outperformed by our new AUC-based permutation VIM for unbalanced data settings, while the performance of both VIMs is very similar in the case of balanced classes. The new AUC-based VIM is implemented in the R package party for the unbiased RF variant based on conditional inference trees. The codes implementing our study are available from the companion website: http://www.ibe.med.uni-muenchen.de/organisation/mitarbeiter/070_drittmittel/janitza/index.html
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The UK WTC 9/11 evacuation study: methodologies used in the elicitation and storage of human factors data
This paper describes the methodologies employed in the collection and storage of first-hand accounts of evacuation experiences derived from face-to-face interviews with evacuees from the World Trade Center (WTC) Twin Towers complex on 11 September 2001. In particular the paper describes the development of the High-rise Evacuation Evaluation Database (HEED). This is a flexible qualitative research tool which contains the full transcribed interview accounts and coded evacuee experiences extracted from those transcripts. The data and information captured and stored in the HEED database is not only unique, but it provides a means to address current and emerging issues relating to human factors associated with the evacuation of high-rise buildings
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The consequence of endothelial remodelling on the blood spinal cord barrier and nociception
Nociception is a fundamental acute protective mechanism that prevents harm to an organism. Understanding the integral processes that control nociceptive processing are fundamental to our appreciation of which cellular and molecular features underlie this process. There is an extensive understanding of how sensory neurons interpret differing sensory modalities and intensities. However, it is widely appreciated that the sensory neurons do not act alone. These work in harmony with inflammatory and vascular systems to modulate pain perception. The spinal cord has an extensive interaction with the capillary network in the form of a blood spinal cord barrier to ensure homeostatic control of the spinal cord neuron milieu. However, there is an extensive appreciation that disturbances in the blood spinal cord barrier contribute to the onset of chronic pain. Enhanced vascular permeability and impaired blood perfusion have both been highlighted as contributors to chronic pain manifestation. Here, we discuss the evidence that demonstrates alterations in the blood spinal cord barrier influences nociceptive processing and perception of pain
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