3,885 research outputs found
Resonant Scattering and Ly-alpha Radiation Emergent from Neutral Hydrogen Halos
With a state-of-the-art numerical method for solving the
integral-differential equation of radiative transfer, we investigate the flux
of the Ly photon emergent from an optically thick halo
containing a central light source. Our focus is on the time-dependent effects
of the resonant scattering. We first show that the frequency distribution of
photons in the halo are quickly approaching to a locally thermalized state
around the resonant frequency, even when the mean intensity of the radiation is
highly time-dependent. Since initial conditions are forgotten during the
thermalization, some features of the flux, such as the two peak structure of
its profile, actually are independent of the intrinsic width and time behavior
of the central source, if the emergent photons are mainly from photons in the
thermalized state. In this case, the difference , where
are the frequencies of the two peaks of the flux, cannot be less
than times of Doppler broadening. We then study the radiative transfer in
the case where the light emitted from the central source is a flash. We
calculate the light curves of the flux from the halo. It shows that the flux is
still a flash. The time duration of the flash for the flux, however, is
independent of the original time duration of the light source but depends on
the optical depth of the halo. Therefore, the spatial transfer of resonant
photons is a diffusion process, even though it is not a purely Brownian
diffusion. This property enables an optically thick halo to trap and store
thermalized photons around for a long time after the cease of the
central source emission. The photons trapped in the halo can yield delayed
emission, of which the profile also shows typical two peak structure as that
from locally thermalized photons. Possible applications of these results are
addressed.Comment: 25 pages, 10 figures, accepted for publication in Ap
Human Trafficking in the Emergency Department
Human trafficking continues to persist, affecting up to 200 million people worldwide. As clinicians in emergency departments commonly encounter victims of intimate partner violence, some of these encounters will be with trafficking victims. These encounters provide a rare opportunity for healthcare providers to intervene and help. This case report of a human trafficking patient from a teaching hospital illustrates the complexity in identifying these victims. Clinicians can better identify potential trafficking cases by increasing their awareness of this phenomenon, using qualified interpreters, isolating potential victims by providing privacy and using simple clear reassuring statements ensuring security. A multidisciplinary approach can then be mobilized to help these patients
Muon Spectra of Quasi-Elastic and 1-Pion Production Events in LBL Neutrino Oscillation Experiments
The muon energy spectra of the quasi-elastic and 1-pion production events in
a LBL experiment, like K2K, are predicted to follow closely the neutrino energy
spectrum, with downward shifts of the energy scale by and respectively. These predictions seem to agree with the
observed muon spectra in the K2K nearby detector. The corresponding muon
spectra in the far-away (SK) detector are predicted to show characteristic
spectral distortions induced by oscillation. Comparison of the
predicted spectral distortions with the observed muon spectra of the 1-Ring and
2-Ring muon events in the SK detector will help to determine the oscillation
parameters. The results will be applicable to other LBL experiments as well.Comment: 13 pages. One figure and a few comments added, final version to
appear in P
Joint QoS multicast routing and channel assignment in multiradio multichannel wireless mesh networks using intelligent computational methods
Copyright @ 2010 Elsevier B.V. All rights reserved.In this paper, the quality of service multicast routing and channel assignment (QoS-MRCA) problem is investigated. It is proved to be a NP-hard problem. Previous work separates the multicast tree construction from the channel assignment. Therefore they bear severe drawback, that is, channel assignment cannot work well with the determined multicast tree. In this paper, we integrate them together and solve it by intelligent computational methods. First, we develop a unified framework which consists of the problem formulation, the solution representation, the fitness function, and the channel assignment algorithm. Then, we propose three separate algorithms based on three representative intelligent computational methods (i.e., genetic algorithm, simulated annealing, and tabu search). These three algorithms aim to search minimum-interference multicast trees which also satisfy the end-to-end delay constraint and optimize the usage of the scarce radio network resource in wireless mesh networks. To achieve this goal, the optimization techniques based on state of the art genetic algorithm and the techniques to control the annealing process and the tabu search procedure are well developed separately. Simulation results show that the proposed three intelligent computational methods based multicast algorithms all achieve better performance in terms of both the total channel conflict and the tree cost than those comparative references.This work was supported by the Engineering and Physical Sciences Research Council (EPSRC) of UK under Grant EP/E060722/1
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Development of a scale to measure individuals’ ratings of peace
Background: The evolving concept of peace-building and the interplay between peace and health is examined in many venues, including at the World Health Assembly. However, without a metric to determine effectiveness of intervention programs all efforts are prone to subjective assessment. This paper develops a psychometric index that lays the foundation for measuring community peace stemming from intervention programs. Methods: After developing a working definition of ‘peace’ and delineating a Peace Evaluation Across Cultures and Environments (PEACE) scale with seven constructs comprised of 71 items, a beta version of the index was pilot-tested. Two hundred and fifty subjects in three sites in the U.S. were studied using a five-point Likert scale to evaluate the psychometric functioning of the PEACE scale. Known groups validation was performed using the SOS-10. In addition, test-retest reliability was performed on 20 subjects. Results: The preliminary data demonstrated that the scale has acceptable psychometric properties for measuring an individual’s level of peacefulness. The study also provides reliability and validity data for the scale. The data demonstrated internal consistency, correlation between data and psychological well-being, and test-retest reliability. Conclusions: The PEACE scale may serve as a novel assessment tool in the health sector and be valuable in monitoring and evaluating the peace-building impact of health initiatives in conflict-affected regions
The Commercial Sexual Exploitation and Sex Trafficking of Minors in the Boston Metropolitan Area: Experiences and Challenges Faced by Front-Line Providers and Other Stakeholders
Objectives: The commercial sexual exploitation of children (CSEC), including sex trafficking of minors, is considered a severe form of abuse and violence against minors. We use a public health lens to examine perceptions regarding the context and process of CSEC and sex trafficking of minors in the Boston area, the response of the health care sector, and opportunities to improve the health and well-being of exploited/trafficked minors.
Methods: Using case study methodology, we conducted 22 semi-structured qualitative interviews of 25 key anti-trafficking stakeholders active in the Boston area.
Results: Key informants identified CSEC involving boys, girls, and transgender youth as a local problem. Many social and economic factors facilitate sex trafficking, including child sexual abuse, domicile instability, and financial insecurity. The health needs of commercially sexually exploited minors are numerous, and local health care services are variable, particularly in the realm of mental health. Various factors function as barriers to a greater health care sector response, including low awareness of CSEC and sex trafficking of minors among health care providers. Gaps in CSEC prevention and response include early recognition of signs and symptoms, CSEC-knowledgeable trauma-sensitive health care services, and emergency shelter.
Conclusions: CSEC, including sex trafficking of minors, is a recognized occurrence in the Boston area that requires a multidisciplinary response across multiple sectors. A more robust health care system response in coordination with other active stakeholders could help enhance the overall impact of local anti-CSEC/trafficking efforts. Increased health trainings, policy advocacy, and the use of multidisciplinary teams may be an effective way to partner across sectors and ensure wraparound services for exploited youth
Will we observe black holes at LHC?
The generalized uncertainty principle, motivated by string theory and
non-commutative quantum mechanics, suggests significant modifications to the
Hawking temperature and evaporation process of black holes. For
extra-dimensional gravity with Planck scale O(TeV), this leads to important
changes in the formation and detection of black holes at the the Large Hadron
Collider. The number of particles produced in Hawking evaporation decreases
substantially. The evaporation ends when the black hole mass is Planck scale,
leaving a remnant and a consequent missing energy of order TeV. Furthermore,
the minimum energy for black hole formation in collisions is increased, and
could even be increased to such an extent that no black holes are formed at LHC
energies.Comment: 5 pages, 2 figures. Minor changes to match version to appear in
Class. Quant. Gra
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Prevalence of Undiagnosed Hypoxemia in Adults and Children in an Under-Resourced District Hospital in Zambia
Background: In adequately resourced clinical environments, diagnosis of hypoxemia via pulse oximetry is routine. Unfortunately, pulse oximetry is rarely utilized in under-resourced hospitals in developing countries. Aim: The prevalence of undiagnosed hypoxemia among adults and children with illnesses other than pneumonia in these environments remains poorly described. Methods: This cross-sectional analysis of the prevalence of hypoxemia was conducted in Kapiri Mposhi, Zambia, at the 60-bed District Hospital, which serves a population of 320,000. The resting room air oxygen saturations of two consecutive samples of all adult and pediatric inpatients were measured in December 2008 and March 2009 using handheld pulse oximetry. Hypoxemia was defined as resting room air SpO less than 90%. Results: A total of 192 patients were enrolled: 68 young children (<5 years old), 15 older children (5-17 years old), and 109 adults (≥18 old). Five young children (7%), 0 older children (0%), and 10 adults (9%) were hypoxemic. No hypoxemic patients were receiving oxygen therapy at the time of diagnosis. Pneumonia, tuberculosis, and malnutrition were the most common conditions among those with hypoxemia. Oximetry data changed clinical management in all observed cases of hypoxemia and several cases of normoxemia, leading to application of supplemental oxygen, initiation of further diagnostic testing, prolongation of inpatient stay, or expedited discharge home. Conclusions: Undiagnosed hypoxemia is present among inpatients at this district hospital in rural Zambia with high prevalence in both adults and young children. These results support routine screening for hypoxemia in similar facilities in both age groups. Further investigation is warranted into the clinical impact and cost-effectiveness of pulse oximetry, provision of oxygen concentrators, and training on their use in developing countries
Health-related quality of life in KEYNOTE-010 : a phase II/III study of pembrolizumab versus docetaxel in patients with previously treated advanced, programmed death ligand 1-expressing NSCLC
Introduction: In the phase II/III KEYNOTE-010 study (ClinicalTrials.gov, NCT01905657), pembrolizumab significantly prolonged overall survival over docetaxel in patients with previously treated, programmed death ligand 1-expressing (tumor proportion score >= 1%), advanced NSCLC. Health-related quality of life (HRQoL) results are reported here. Methods: Patients were randomized 1:1:1 to pembrolizumab 2 or 10 mg/kg every 3 weeks or docetaxel 75 mg/m(2) every 3 weeks. HRQoL was assessed using European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (QLC) Core 30 (C30), EORTC QLQ-Lung Cancer 13 (LC13), and EuroQoL-5D. Key analyses included mean baseline-to-week-12 change in global health status (GHS)/quality of life (QoL) score, functioning and symptom domains, and time to deterioration in a QLQ-LC13 composite endpoint of cough, dyspnea, and chest pain. Results: Patient reported outcomes compliance was high across all three instruments. Pembrolizumab was associated with better QLQ-C30 GHS/QoL scores from baseline to 12 weeks than docetaxel, regardless of pembrolizumab dose or tumor proportion score status (not significant). Compared with docetaxel, fewer pembrolizumab-treated patients had "deteriorated" status and more had "improved" status in GHS/QoL. Nominally significant improvement was reported in many EORTC symptom domains with pembrolizumab, and nominally significant worsening was reported with docetaxel. Significant prolongation in true time to deterioration for the QLQ-LC13 composite endpoint emerged for pembrolizumab 10 mg/kg compared to docetaxel (nominal two-sided p = 0.03), but not for the 2-mg/kg dose. Conclusions: These findings suggest that HRQoL and symptoms are maintained or improved to a greater degree with pembrolizumab than with docetaxel in this NSCLC patient population. (C) 2019 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.
Provider experiences with improvised uterine balloon tamponade for the management of uncontrolled postpartum hemorrhage in Kenya
AbstractObjectiveTo understand healthcare providers’ experiences with improvised uterine balloon tamponade (UBT) for the management of uncontrolled postpartum hemorrhage (PPH).MethodsIn a qualitative descriptive study, in-depth semi-structured interviews were conducted between November 2014 and June 2015 among Kenyan healthcare providers who had previous experience with improvising a UBT device. Interviews were conducted, audio-recorded, and transcribed.ResultsOverall, 29 healthcare providers (14 nurse-midwifes, 7 medical officers, 7 obstetricians, and 1 clinical officer) were interviewed. Providers perceived improvised UBT as valuable for managing uncontrolled PPH. Reported benefits included effectiveness in arresting hemorrhage and averting hysterectomy, and ease of use by providers of all levels of training. Providers used various materials to construct an improvised UBT. Challenges to improvising UBT—e.g. searching for materials during an emergency, procuring male condoms, and inserting fluid via a small syringe—were reported to lead to delays in care. Providers described their introduction to improvised UBT through both formal and informal sources. There was universal enthusiasm for widespread standardized training.ConclusionImprovised UBT seems to be a valuable second-line treatment for uncontrolled PPH that can be used by providers of all levels. UBT might be optimized by integrating a standard package across the health system
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