749 research outputs found
The Effects of Body-Worn Cameras on Police Activity and Police-Citizen Encounters: A Randomized Controlled Trial
Many have suggested that placing body-worn cameras (BWCs) on police officers improves the civility of police-citizen encounters and enhances citizen perceptions of police transparency and legitimacy. In response, many police departments have adopted this technology to address public concerns over the quality of policing in their communities. The existing program evaluation evidence on the intended and unintended consequences of outfitting police officers with BWCs is still developing, however. This study reports the findings of a randomized controlled trial involving more than 400 police officers in Las Vegas, Nevada. We find that officers equipped with body-worn cameras generated fewer complaints and use of force reports relative to officers without cameras. BWC officers also made more arrests and issued more citations than their non-BWC counterparts. The findings of this randomized controlled trial raise the possibility that planning for the placement of BWCs on officers should consider the competing effects of improvement in civilian perceptions of police generated by reductions in complaints and use of force incidents and of public concerns about increased enforcement activity
A review of capture-recapture methods and its possibilities in ophthalmology and vision sciences
Epidemiological information is expected to be used to develop key aspects of eye care such as to control and minimise the impact of diseases, to allocate resources, to monitor public health actions, to determine the best treatment options and to forecast the consequence of diseases in populations. Epidemiological studies are expected to provide information about the prevalence and/or incidence of eye diseases or conditions. To determine prevalence is necessary to perform a cross-sectional screening of the population at risk to ascertain the number of cases.The aim of this review is to describe and evaluate capture-recapture methods (or models) to ascertaining the number of individuals with a disease (e.g. diabetic retinopathy) or condition (e.g. vision impairment) in the population.The review covers the fundamental aspects of capture-recapture methods that would enable non-experts in epidemiology to use it in ophthalmic studies. The review provides information about theoretical aspects of the method with examples of studies in ophthalmology in which it has been used. We also provide a problem/solution approach for limitations arising from the lists obtained from registers or other reliable sources.We concluded that capture-recapture models can be considered reliable to estimate the total number of cases with eye conditions using incomplete information from registers. Accordingly, the method may be used to maintain updated epidemiological information about eye conditions helping to tackle the lack of surveillance information in many regions of the globe.- This study was supported by FCT (COMPETE/QREN) grant reference [PTDC/DPT-EPI/0412/2012] in the context of the Prevalence and Costs of Visual Impairment in Portugal: a hospital-based study (PCVIP-study) and FCT Strategic Funding UID/FIS/04650/2013. PLR is funded by FCT (COMPETE/QREN) grant reference [SFRH/BD/119420/2016]
A Rotating Panel Survey to Assess Quality of Hunter College Education
A rotating sample design is proposed to most accurately measure the perceived quality of a Hunter College education. A representative sample of Hunter College students will belong to one of six rotating panels. Students will be contacted during four rotation periods and report their assessment of the two most recent months. It is advantageous to use a rotating panel design as opposed to a fixed panel design in order to guard against the negative effects of a deteriorating response rate. Stratified sampling will help to ensure representation across major departments and academic year of study. Methods for sampling procedures, stratification, understanding net changes, and survey question organization are outlined in this paper
Study of the impact of the post-MS evolution of the host star on the orbits of close-in planets. I. Sample definition and physical properties
Context: To date, more than 30 planets have been discovered around giant
stars, but only one of them has been found to be orbiting within 0.6 AU from
the host star, in direct contrast to what is observed for FGK dwarfs. This
result suggests that evolved stars destroy/engulf close-in planets during the
red giant phase.
Aims: We are conducting a radial velocity survey of 164 bright G and K giant
stars in the southern hemisphere with the aim of studying the effect of the
host star evolution on the inner structure of planetary systems. In this paper
we present the spectroscopic atmospheric parameters (\Teff, \logg, ,
[Fe/H]) and the physical properties (mass, radius, evolutionary status) of the
program stars. In addition, rotational velocities for all of our targets were
derived.
Methods: We used high resolution and high S/N spectra to measure the
equivalent widths of many Fe{\sc\,i} and Fe{\sc\,ii} lines, which were used to
derive the atmospheric parameters by imposing local thermodynamic and
ionization equilibrium. The effective temperatures and metallicities were used,
along with stellar evolutionary tracks to determine the physical properties and
evolutionary status of each star.
Results: We found that our targets are on average metal rich and they have
masses between \,1.0\,M and 3.5\,M. In addition, we found
that 122 of our targets are ascending the RGB, while 42 of them are on the HB
phase.Comment: Accepted for publication in A&
Geometrical distribution of Cryptococcus neoformans mediates flower-like biofilm development
Microbial biofilms are highly structured and dynamic communities in which phenotypic diversification allows microorganisms to adapt to different environments under distinct conditions. The environmentally ubiquitous pathogen Cryptococcus neoformans colonizes many niches of the human body and implanted medical devices in the form of biofilms, an important virulence factor. A new approach was used to characterize the underlying geometrical distribution of C. neoformans cells during the adhesion stage of biofilm formation. Geometrical aspects of adhered cells were calculated from the Delaunay triangulation and Voronoi diagramobtained fromscanning electronmicroscopy images (SEM). A correlation between increased biofilm formation and higher ordering of the underlying cell distribution was found. Mature biofilm aggregates were analyzed by applying an adapted protocol developed for ultrastructure visualization of cryptococcal cells by SEM. Flower-like clusters consisting of cells embedded in a dense layer of extracellular matrix were observed as well as distinct levels of spatial organization: adhered cells, clusters of cells and community of clusters. The results add insights into yeast motility during the dispersion stage of biofilm formation. This study highlights the importance of cellular organization for biofilm growth and presents a novel application of the geometrical method of analysis
TESS asteroseismology of the known red-giant host stars HD 212771 and HD 203949
International audienc
Conversion of typical to "atypical" atrioventricular nodal reentrant tachycardia after radiofrequency catheter modification of the atrioventricular junction
Typical atrioventricular (AV) nodal reentry tachycardia (AVNRT) is characterized by anterograde activation over a slowly conducting pathway and by retrograde activation through a rapidly conducting pathway. Preliminary reports suggest that radiofrequency catheter modification can eliminate typical AVNRT while preserving anterograde conduction. Radiofrequency catheter modification was used to treat 88 patients with typical AVNRT. After baseline electrophysiologic evaluation, the ablation catheter was positioned proximal and superior to the site of maximal His deflection. Radiofrequency energy was applied until there was significant attenuation of retrograde conduction, and elimination of AVNRT inducibility. Eighty-one patients were successfully treated and form the basis of this report.A new paroxysmal supraventricular tachycardia with RP > PR interval was induced at electrophysiologic testing after successful ablation in 9 patients (11%). Mean atrial-His activation time was 140 +/- 31 ms, and the ventriculoatrial activation time was 170 +/- 46 ms. This arrhythmia was induced only with ventricular pacing during isoproterenol infusion and appeared to be mediated by AV nodal reentry. New retrograde dual AV nodal physiology after modification was more frequent in patients with atypical tachycardia than in those without (4 of 9 vs 2 of 72; p Results of this study confirm that typical AVNRT can be rendered noninducible without the complete destruction of reentrant pathways. Because induction of "atypical" AVNRT was not predictive of spontaneous arrhythmia recurrence, it should not be an indication for additional ablation sessions or long-term drug therapy.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/30203/1/0000593.pd
Reduction in medical care cost associated with radiofrequency catheter ablation of accessory pathways
The cost of definitive therapy was compared in 25 patients who underwent radiofrequency catheter ablation of accessory pathways in 1990 and 25 patients who underwent surgical ablation of accessory pathways in 1989. In the radiofrequency group, 23 of 25 patients had a single accessory pathway and the remaining 2 patients each had 2 accessory pathways. In the surgical group, 20 patients had a single accessory pathway and 5 patients each had 2 accessory pathways. The success rate was 96% in each group. The mean duration of hospitalization was 3 +/- 1 days in the radiofrequency group and 9 +/- 4 days in the surgical group (p < 0.0001). All the cost data are expressed in fiscal year 1990/1991 dollar values. The total cost of therapy in the radiofrequency group was 6,740 compared with 12,755 in the surgical group (p < 0.0001). The cost of radiofrequency ablation consisted of a hospital charge of 3,472 and physician fees of 3,439. The hospital charge included charges for use of the electrophysiology laboratory, hospital stay, electrocardiograms, echocardiograms and blood studies. The cost of surgery consisted of a hospital charge of 10,179 and physician fees of 3,149. The hospital charge in the surgical group included the costs of a baseline electrophysiology study, in-hospital care and a follow-up office visit. In conclusion, radiofrequency catheter ablation of accessory pathways results in a dramatic reduction in the cost of definitive therapy in patients with the Wolff-Parkinson-White syndrome.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/28980/1/0000007.pd
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
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