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Victimisation by the police is purported to be widespread in cities in the USA, but there is limited data on police–public encounters from community samples. This is partly due to an absence of measures for assessing police violence exposure from the standpoint of civilians. As such, the demographic distribution and mental health correlates of police victimisation are poorly understood. The aims of this study were to present community-based prevalence estimates of positive policing and police victimisation based on assessment with two novel measures, and to test the hypotheses that (1) exposure to police victimisation would vary across demographic groups and (2) would be associated with depression and psychological distress.
The Survey of Police–Public Encounters study surveyed adults residing in four US cities to examine the prevalence, demographic distribution and psychological correlates of police victimisation. Participants (N = 1615) completed measures of psychological distress (K-6 scale), depression (Patient Health Questionnaire 9) and two newly constructed measures of civilian-reported police–public encounters. Both measures were developed to assess police victimisation based on the WHO domains of violence, which include physical violence (with and without a weapon, assessed separately), sexual violence (inappropriate sexual contact, including public strip searches), psychological violence (e.g., threatening, intimidating, stopping without cause, or using discriminatory slurs) and neglect (police not responding when called or responding too late). The Police Practices Inventory assesses lifetime history of exposure to positive policing and police victimisation, and the Expectations of Police Practices Scale assesses the perceived likelihood of future incidents of police victimisation. Linear regression models were used to test for associations between police–public encounters and psychological distress and depression.
Psychological violence (18.6%) and police neglect (18.8%) were commonly reported in this sample and a substantial minority of respondents also reported more severe forms of violence, specifically physical (6.1%), sexual (2.8%) and physical with a weapon (3.3%). Police victimisation was more frequently reported by racial/ethnic minorities, males, transgender respondents and younger adults. Nearly all forms of victimisation (but not positive policing) were associated with psychological distress and depression in adjusted linear regression models.
Victimisation by police appears to be widespread, inequitably distributed across demographic groups and psychologically impactful. These findings suggest that public health efforts to both reduce the prevalence of police violence and to alleviate its psychological impact may be needed, particularly in disadvantaged urban communities.
Thin films of AlxGa1−xN (0.05 ≤ x ≤ 0.96) having smooth surfaces were deposited directly on both vicinal and on-axis 6H-SiC(0001) substrates. Cross-sectional TEM of Al0.13Ga0.87N revealed stacking faults near the SiC/Nitride alloy interface and numerous threading dislocations. EDX, AES and RBS were used to determine the compositions, which were paired with their respective CL near band-edge emission energies. A negative bowing parameter was determined. The CL emission energies were similar to the bandgap energies obtained by SE. FE-AES of the initial growth of Al0.2Ga0.8N revealed an aluminum rich layer near the interface. N-type (silicon) doping was achieved for AlxGa1−xN for 0.12 ≤ x ≤ 0.42. Al0.2Ga0.8N/GaN superlattices were fabricated with coherent interfaces. Additionally, HEMT structures using an AlN/GaN/AlN buffer structure were fabricated.
The UFFO (Ultra-Fast Flash Observatory) is a GRB detector on board the Lomonosov
satellite, to be launched in 2013. The GRB trigger is provided by an X-ray detector,
called UBAT (UFFO Burst Alarm & Trigger Telescope), which detects X-rays from the GRB
and then triggers to determine the direction of the GRB and then alerts the Slewing Mirror
Telescope (SMT) to turn in the direction of the GRB and record the optical photon fluxes.
This report details the calibration of the two components: the MAPMTs and the YSO crystals
and simulations of the UBAT. The results shows that this design can observe a GRB within a
field of view of ±35° and can trigger in a time scale as short as 0.2 – 1.0 s
after the appearance of a GRB X-ray spike.
The Ultra-Fast Flash Observatory (UFFO) Pathfinder for Gamma-Ray Bursts (GRBs) consists
of two telescopes. The UFFO Burst Alert & Trigger Telescope (UBAT) handles the
detection and localization of GRBs, and the Slewing Mirror Telescope (SMT) conducts the
measurement of the UV/optical afterglow. UBAT is equipped with an X-ray detector, analog
and digital signal readout electronics that detects X-rays from GRBs and determines the
location. SMT is equipped with a stepping motor and the associated electronics to rotate
the slewing mirror targeting the GRBs identified by UBAT. First the slewing mirror points
to a GRB, then SMT obtains the optical image of the GRB using the intensified CCD and its
readout electronics. The UFFO Data Acquisition system (UDAQ) is responsible for the
overall function and operation of the observatory and the communication with the satellite
main processor. In this paper we present the design and implementation of the electronics
of UBAT and SMT as well as the architecture and implementation of UDAQ.
The Ultra-Fast Flash Observatory (UFFO), which will be launched onboard the
Lomonosov spacecraft, contains two crucial instruments: UFFO Burst
Alert & Trigger Telescope (UBAT) for detection and localization of Gamma-Ray Bursts
(GRBs) and the fast-response Slewing Mirror Telescope (SMT) designed for the observation
of the prompt optical/UV counterparts. Here we discuss the in-space calibrations of the
UBAT detector and SMT telescope. After the launch, the observations of the standard X-ray
sources such as pulsar in Crab nebula will provide data for necessary calibrations of
UBAT. Several standard stars will be used for the photometric calibration of SMT. The
celestial X-ray sources, e.g. X-ray binaries with bright optical sources
in their close angular vicinity will serve for the cross-calibration of UBAT and SMT.
The Ultra-Fast Flash Observatory (UFFO) is a space mission to detect the early moments of an explosion from Gamma-ray bursts (GRBs), thus enhancing our understanding of the GRB mechanism. It consists of the UFFO Burst & Trigger telescope (UBAT) for the recognition of GRB positions using hard X-ray from GRBs. It also contains the Slewing Mirror Telescope (SMT) for the fast detection of UV-optical photons from GRBs. It is designed to begin the UV-optical observations in less than a few seconds after the trigger. The UBAT is based on a coded-mask X-ray camera with a wide field of view (FOV) and is composed of the coded mask, a hopper and a detector module. The SMT has a fast rotatable mirror which allows a fast UV-optical detection after the trigger. The telescope is a modified Ritchey-Chrétien telescope with the aperture size of 10 cm diameter, and an image intensifier readout by CCD. The UFFO pathfinder is scheduled to launch into orbit on 2012 June by the Lomonosov spacecraft. It is a scaled-down version of UFFO in order to make the first systematic study of early UV/optical light curves, including the rise phase of GRBs. We expect UBAT to trigger ~44 GRBs/yr and expect SMT to detect ~10 GRBs/yr.
Titanium silicides were prepared by coevaporation of Ti and Si on Si substrates at intermediate substrate temperatures followed by high temperature annealing. Depending on the deposition conditions, transmission electron diffraction analyses revealed two different halo patterns from the as-deposited samples. Variations in the deposition conditions included substrate temperature, deposition rate, and film thickness. Radial distribution functions were calculated to estimate the short range ordering of the amorphous phases. The interatomic distances of all the titanium silicide compounds were also calculated in order to compare them with the atomic ordering of amorphous phases. Phase transition from these amorphous phases to the first crystalline silicide is discussed in terms of kinetic variations as well as the atomic ordering.
Thermodynamic functions of Co-Si and Au-Si systems were studied. The validity of these functions were confirmed by successfully calculating phase diagrams. It was revealed that the composition of the first nucleated compound is close to the concentration of the minimum free energy of the liquid alloy with respect to the two solid components (ΔG) of the binary systems. In addition, the minimum ΔG concentration was found to be located by interpolating the portion of the liquidus, where the liquid alloy is in equilibrium with the two solid constituents, into the central region of the diagram where compounds exist. The minimum ΔG concentration of other silicide and germanide systems were estimated by the suggested interpolation method. A new model for predicting the first nucleated compound in silicide as well as germanide systems was proposed based on the findings.
Metal-insulator-semiconductor (MIS) capacitors have been fabricated on n-type GaN (0001) films using thermally grown Ga2O3, remote plasma enhanced chemical vapor deposited (RPECVD) SiO2, and molecular beam epitaxy (MBE) AIN as the gate insulator and Al as the gate electrode. Each GaN epitaxial layer was grown by organometallic chemical vapor deposition (OMCVD) on a 6H-SiC(0001) substrate on which was previously deposited a 1000Å buffer layer of AIN. Nitrogen-free polycrystalline films of Ga2O3 were grown on the GaN. Capacitancevoltage measurements of capacitors fabricated from this oxide showed distinct depletion and accumulation regions with significant leakage. The AIN and SiO2 capacitors demonstrated better electrical characteristics than the Ga2O3 because of lower leakage. The RPECVD SiO2/GaN heterostructures, in particular, showed good agreement with the curves calculated for an ideal oxide and a small amount of hysteresis.
Rapid thermal annealing (RTA) was applied to anneal polycrystalline CdTe thin films evaporated on CdS/ITO substrate and the effects of rapid thermal annealing temperatures and gas environments were studied. X-ray diffractometer (XRD), X-ray photoelectron spectroscopy(XPS), energy dispersive X-ray spectroscopy(EDX), cross-sectional transmission microscopy(TEM), and micro-EDX in TEM were used to characterize physical and chemical properties of rapid thermal annealed CdTe thin films. Complete CdTe/CdS photovoltaic cells were fabricated and I-V characteristics of these cells were measured under the illumination. Results showed that the bulk composition of CdTe remained stoichiometric to 550°C in the air environment and surface composition became Cd-rich. Cross-sectional TEM and micro-EDX showed columnar grains and micro-twins remained even after RTA, however, sulfur content in rapid thermal annealed CdTe caused by sulfur diffusion from CdS during the annealing was much smaller than that by furnace annealing. Among the investigated RTA temperatures and gas environments, the cell made with CdTe annealed at 550°C in the air showed the best solar energy conversion efficiency.
In this work, we have conducted a systematic investigation of leakage current and electrical breakdown of plasma enhanced chemical vapor deposited (PECVD) silicon nitride, both for planar films and deposited films on the vertical sidewall for the application of the vertical thin film transistors. The thickness evolution of physical properties and electrical characteristics of silicon nitride films in the range of 50 to 300 nm are investigated. Electrical breakdown strength for 150-300nm thick films was approximately 7 MV/cm, whereas the value dropped to ~3MV/cm for 50nm thick films deposited under the same process conditions. It is shown that the early failure of the thin nitride is accompanied by the increase of the pinholes number. For the vertical thin film transistors, the experimental result shows the reliability and leakage current of the gate dielectric depends on the step coverage of the silicon nitride film on the vertical sidewall.
The electrical characteristics of SiH4-based PECVD gate oxide have been investigated with respect to gate oxide integrity (GOI) and its reliability. It was found that the GOI of poly-Si TFT integrated on glass substrate strongly depended on the charge trapping and deep level interface states generation under Fowler-Nordheim stress (FNS). By applying elevated temperature postanneal without vacuum break after the gate oxide deposition, highly reliable gate oxide was obtained. Under FNS, ID-VG curve showed severe shift and degradation of subthreshold slope, which were reduced by adopting post-annealed gate oxide. Besides, the TFT with post-annealed gate oxide showed around 10 times higher charge to breakdown than that of as-deposited gate oxide. Charge to breakdown of MOS capacitors were also studied. By applying post-annealed gate oxide, charge to breakdown drastically improved, which could be explained by reduced charge trapping under FNS.
We have successfully obtained large lateral grains with well-controlled grain boundary. The proposed excimer laser annealing (ELA) method produces 2-dimensionally controlled grain growth because the temperature gradient is induced in two directions. Along the channel direction, the floating active structure produces large thermal gradient due to very low thermal conductivity of the air-gap. Along the perpendicular direction to the channel, the surface tension effect also produces thermal gradient. The proposed ELA method can control the grain boundary perpendicular and parallel to current path with only one laser irradiation.
Incomplete recrystallized junction defects of self-aligned, excimer laser annealed polycrystalline silicon (poly-Si) thin film transistor (TFT) was investigated by high-resolution transmission electron microscopy (HR-TEM). TEM observation and simulation result verify that the laser irradiation intensity decreased remarkably at the junction due to diffraction of laser beam at gate electrode edge. We proposed oblique-incidence excimer laser annealing method and successfully eliminated the residual junction defects.
Recent technological advances in various fields of applied science have radically transformed the strategies and vision of biomedical research. While only a few decades ago scientists were largely restricted to studying parts of biological systems in isolation, mathematical and computational modelling now enable the use of holistic approaches to analyse data spanning multiple biological levels and traditionally disconnected fields.
Mathematical modelling of organs and systems is a new frontier in the biosciences and promises to provide a comprehensive understanding of complex biological phenomena as more than the sum of their parts. Recognizing this opportunity, many academic centres worldwide have established new focuses on this rapidly expanding field that brings together scientists working in applied mathematics, mechanics, computer science, bioengineering, physics, biology and medicine. A common goal of this effort is to stimulate the study of challenging problems in medicine on the basis of abstraction, modelling and general physical principles.
This book is intended for bioengineers, applied mathematicians, biologists and doctors. It provides a brief and rigorous introduction to the mathematical foundations of thin-shell theory and its applications to nonlinear problems of the biomechanics of hollow abdominal viscera. It should be stressed that the text is not directed towards rigorous mathematical proofs of methods and solutions, but rather to a thorough comprehension, by means of mathematical exercises, of the essentials and the limitations of the theory and its role in the study of biomedical phenomena.