301 research outputs found
A Study of the Knowledge and Attitudes of Physicians Toward Victims of Spouse Abuse
The purpose of this study is to measure the knowledge and attitudes of physicians toward victims of spouse abuse. All 150 practitioners in the specialities of emergency medicine, family medicine, obstetrics-gynecology and psychiatry, in a large area general hospital are included in the sampling frame; 76 responded (RR = 51%). Knowledge and attitudes were measured using the Physician Survey on Spouse Abuse. Rosenberg\u27s Tripartite Model of Attitude formed the theoretical basis for this study. Participants were 72% male, 90% white, 88% currently married, with a mean age of 44 years (SD = 7.99). Mean years in practice was 14.61 (SD = 7.71); 63% were in private practice, and 47% practiced in suburban areas. A minority, 21% had no course content on spouse abuse and majority, 81% were not trained in spouse abuse prevention following graduation.
Only 27% secured a pass on the knowledge quiz. 68% had positive summary attitude measure. 70% had a positive overall belief, 97% had positive beliefs about physician role, 65% had positive beliefs about victims, and 30% had positive beliefs about resources. 11% had a positive affect score. 84% had positive verbal statements of behavior, 22% had positive behaviors on frequency of suspecting abuse. 50% of the respondents identified 5 or less victims in the past year. Whites had significantly less positive summary attitude measure, beliefs about physician role, and affect scores. Older physicians had significantly less positive overall belief scores, beliefs about victims and identified fewer victims of abuse. Females were significantly more likely to pass the knowledge quiz and they were also more likely to hold positive beliefs about victims of abuse. Married physicians were significantly less likely to pass the knowledge quiz and to have less positive affect scores. Family practitioners were least likely to behave positively toward victims of abuse. Physicians with fewer years in practice were more likely to have positive beliefs about victims. Speciality was the strongest predictor of attitudes.
Physicians seem to hold most positive beliefs, are less likely behave positively toward victims of abuse and are even less likely to feel positive about providing services to victims of abuse
Local Measurement of Flow Boiling Heat Transfer in an Array of Non-Uniformly Heated Microchannels
As electronics packages become increasingly thinner and more compact due to size, weight, and performance demands, the use of large intermediate heat spreaders to mitigate heat generation non-uniformities are no longer a viable option. Instead, non-uniform heat flux profiles produced from chip-scale variations or from multiple discrete devices are experienced directly by the ultimate heat sink. In order to address these thermal packaging trends, a better understanding of the impacts of non-uniform heating on two-phase flow characteristics and thermal performance limits for microchannel heat sinks is needed. An experimental investigation is performed to explore flow boiling phenomena in a microchannel heat sink with hotspots, as well as non-uniform streamwise and transverse peak-heating conditions spanning across the entire heat sink area. The investigation is conducted using a silicon microchannel heat sink with a 5 x 5 array of individually controllable heaters attached to a 12.7 mm x 12.7 mm square base. The channels are 240 lm wide, 370 lm deep, and separated by 110 lm wide fins. The working fluid is the dielectric fluorinert liquid FC-77, flowing at a mass flux of approximately 890 kg/m2 s. High-speed visualizations of the flow are recorded to observe the local flow regimes. Despite the substrate beneath the microchannels being very thin (200 lm), significant lateral conduction occurs and must be accounted for in the calculation of the local heat flux imposed. For non-uniform heat input profiles, with peak heat fluxes along the streamwise and transverse directions, it is found that the local flow regimes, heat transfer coefficients, and wall temperatures deviate significantly from a uniformly heated case. These trends are assessed as a function of an increase in the relative magnitude of the nonuniformity between the peak and background heat fluxes
Effects of Non-Uniform Heating on the Location and Magnitude of Critical Heat Flux in a Microchannel Heat Sink
Decreasing form factors and diminishing numbers of thermal interfaces and spreading layers in modern, compact electronic packages result in non-uniform heat generation profiles at the chip level being transmitted directly to the heat sinks. An improved understanding of the effects of non-uniform heating on the heat dissipation limits in microchannel heat sinks has become essential. An experimental investigation is conducted to measure the location and magnitude of critical heat flux (CHF) in a microchannel heat sink exposed to a range of non-uniform heating profiles. A 12.7 mm Ă 12.7 mm silicon microchannel heat sink with an embedded 5 Ă 5 array of individually controllable heaters is used in the experiments. The microchannels in the heat sink are 240 mm wide and 370 micrometers deep, and are separated by 110 mm wide fins. The dielectric fluid HFE-7100 is used as the coolant, with an average mass flux in the heat sink of approximately 800 kg/m2s. High-speed visualizations of the flow are recorded to capture the CHF phenomena observed. A central âhotspotâ spanning the entire length of the heat sink in the flow direction (formed by heating only the central 20 percent of the base area) produced both the largest wall excess temperature and the lowest CHF of all the heat flux distributions investigated, due to the flow maldistribution induced. A single transverse hotspot spanning the heat sink perpendicular to the flow direction resulted in different CHF values based on its streamwise location; CHF was largest when the hotspot was placed nearest the inlet and smallest when placed nearest the outlet. The visualizations revealed that CHF occurs when there is a sudden and unalleviated upstream expansion of vapor in one or more channels above the hotspot, causing the local wall temperature to rapidly increase. The proximity of the hotspot to the inlet manifold, which communicates between all channels and can relieve downstream vapor expansion, appears to determine the resiliency of the heat sink to conditions leading to CHF
How Physicians Feel About Assisting Female Victims of Intimate-Partner Violence
Purpose. To assess the feelings of physicians about assisting female victims of intimate-partner violence (IPV), and to examine factors related to positive and negative feelings about assisting victims of IPV. Method. In 1998, a total site sample of 150 physicians practicing in a large general hospital in the area of Virginia Beach, Virginia, was surveyed by questionnaire via the mail. Four specialties were represented: emergency medicine, family practice, obstetrics-gynecology, and psychiatry. The questionnaire asked about medical training and training in assisting victims of IPV The physicians\u27 feelings about working with victims of IPV were measured on a nine-item, five-point semantic differential scale. Results. A total of 76 physicians responded to the questionnaire (response rate=51%). Only a minority (11%) had overall positive feeling scores about assisting victims of IPV While most physicians reported that it was significant work, the great majority also felt that it was difficult, low-paying, and stressful. Training in assisting victims of IPV, in medical school or afterwards, did not appear to influence feelings about assisting victims of IPV However, physicians who were white and who were married (the majority of the respondents) were significantly more likely than the other respondents to feel negatively about providing services to victims of IPV. Conclusion. Graduate medical education and training programs need to address the association of negative feelings with helping women harmed by IPV, because these feelings may interfere with the appropriate screening, referral, and treatment of these victims
Design of a Non-intrusive Electrical Impedance-Based Void Fraction Sensor for Microchannel Two-Phase Flows
.A non-intrusive electrical impedance-based sensor is developed for measurement of local void fraction in air-water adiabatic flow through rectangular microchannels. Measurement of the void fraction in microchannels is essential for the formulation of two-phase flow heat transfer and pressure drop correlations, and may enable real-time flow regime control and performance prediction in the thermal regulation of high-heat-flux devices. The impedance response of the sensor to a range of flow regimes is first investigated in a crosswise (transverse) configuration with two aligned electrodes flush-mounted on opposing microchannel walls. Numerical simulations performed on a multi-phase domain constructed from three-dimensional reconstruction of experimentally observed phase boundaries along with the corresponding experimental results serve to establish the relationship between void fraction and dimensionless impedance for this geometric configuration. A reduced-order analytical model developed based on an assumption of stratified gas-liquid flow allows ready extension of these calibration results to different working fluids of interest. An alternative streamwise sensor configuration is investigated with two electrodes flush-mounted along a single wall in the flow direction in view of its potentially simpler practical implementation in arrays of microchannels. It is shown that a correlation between time-averaged impedance and void fraction can be established for this alternative configuration as well
Design of Multifunctional LatticeâFrame Materials for Compact Heat Exchangers
Structured porous materials show great potential as extended surfaces in heat-exchange applications that also require design for load-bearing capability. In particular, lattice-frame materials (LFM) are known for their superior strength-to-weight ratio; this work presents a comprehensive experimental and numerical study of fluid flow and heat transfer in porous LFMs. Flow through a periodic unit cell of the material is simulated to characterize the forced-convection performance under hydraulically and thermally fully developed conditions. The performance of LFMs with a tetrahedral ligament configuration is characterized as a function of Reynolds number in the laminar regime (150 \u3c Re \u3c 1000) in terms of Nusselt number and friction factor; the effect of porosity is studied by changing the ligament diameter. Experiments are performed for a subset of porosities to validate the numerical approach. A method is demonstrated for utilizing the simulation results, which assume perfect surface efficiency, to predict the performance of LFMs with non-ideal surface efficiency, based on the conduction resistance of the ligaments. It is shown that the thermal behavior of the ligaments closely matches that of cylindrical fins in cross flow and that this analogy can be used to calculate the overall surface efficiency. The implications of the current results on the design of compact heat exchangers using LFMs is assessed using several conventional performance metrics. Our analysis illustrates the challenges in defining any one universal performance metric for compact heat exchanger design; an appropriate performance metric must be selected that accounts for the particular multifunctional performance characteristics of interest. LFMs are shown to provide the benefits of high-porosity and high surface area-to-volume ratio of materials such as metal foams, while also incurring lower pressure drops and displaying higher structural integrity. This makes them ideal for heat exchangers in aerospace and other applications demanding such multifunctional capabilities. The characterization provided in this study readily allows LFM designs for heat exchanger applications with combined heat-transfer and pressure-drop constraints
Boiling Heat Transfer from an Array of Round Jets with Hybrid Surface Enhancements
The effect of a variety of surface enhancements on the heat transfer achieved with an array of impinging jets is experimentally investigated using the dielectric fluid HFE-7100 at different volumetric flow rates. The performance of a 5x5 array of jets, each 0.75mm in diameter, is compared to that of a single 3.75mm diameter jet with the same total open orifice area, in single-and two-phase operation. Four different target copper surfaces are evaluated: a baseline smooth flat surface, a flat surface coated with a microporous layer, a surface with macroscale area enhancement (extended square pinâfins), and a hybrid surface on which the pinâfins are coated with the microporous layer; area-averaged heat transfer and pressure drop measurements are reported. The array of jets enhances the single-phase heat transfer coefficients by 1.13â1.29 times and extends the critical heat flux (CHF) on all surfaces compared to the single jet at the same volumetric flow rates. Additionally, the array greatly enhances the heat flux dissipation capability of the hybrid coated pinâfin surface, extending CHF by 1.89â2.33 times compared to the single jet on this surface, with a minimal increase in pressure drop. The jet array coupled with the hybrid enhancement dissipates a maximum heat flux of 205.8 W/cm2 (heat input of 1.33 kW) at a flow rate of 1800 ml/min (corresponding to a jet diameter-based Reynolds number of 7800) with a pressure drop incurred of only 10.9 kPa. Compared to the single jet impinging on the smooth flat surface, the array of jets on the coated pinâfin enhanced surface increased CHF by a factor of over four at all flow rates
Calibration and Uncertainty Analysis of a Fixed-Bed Adsorption Model for CO2 Separation
Fixed-bed adsorption is widely used in industrial gas separation and is the primary method for atmosphere revitalization in space. This paper analyzes the uncertainty of a one-dimensional, fixed-bed adsorption model due to uncertainty in several model inputs, namely, the linear-driving-force (LDF) mass transfer coefficient, axial dispersion, heat transfer coefficients, and adsorbent properties. The input parameter uncertainties are determined from a comprehensive survey of experimental data in the literature. The model is first calibrated against experimental data from intra-bed centerline concentration measurements to find the LDF coefficient. We then use this LDF coefficient to extract axial dispersion coefficients from mixed, downstream concentration measurements for both a small-diameter bed (dominated by wall-channeling) and a large-diameter bed (dominated by pellet-driven dispersion). The predicted effluent concentration and temperature profiles are most strongly affected by uncertainty in LDF coefficient, adsorbent density, and void fraction. The uncertainty analysis further reveals that ignoring the effect of wall-channeling on apparent axial dispersion can cause significant error in the predicted breakthrough times of small-diameter beds
Beyond behaviour as individual choice: a call to expand understandings around social science in health research
The focus of behavioural sciences in shaping behaviour of individuals and populations is well documented. Research and practice insights from behavioural sciences improve our understanding of how people make choices that in turn determine their health, and in turn the health of the population. However, we argue that an isolated focus on behaviour - which is one link in a chain from macro to the micro interventions - is not in sync with the public health approach which per force includes a multi-level interest. The exclusive focus on behaviour manipulation then becomes a temporary solution at best and facilitator of reproduction of harmful structures at worst. Several researchers and policymakers have begun integrating insights from behavioural economics and related disciplines that explain individual choice, for example, by the establishment of Behavioural Insight Teams, or nudge units to inform the design and implementation of public health programs. In order to comprehensively improve public health, we discuss the limitations of an exclusive focus on behaviour change for public health advancement and call for an explicit integration of broader structural and population-level contexts, processes and factors that shape the lives of individuals and groups, health systems and differential health outcomes
Clinical response to primary letrozole therapy in elderly patients with early breast cancer : possible role for p53 as a biomarker
Primary tamoxifen therapy has been widely used to treat elderly women with ER-positive breast cancer in the past. Aromatase inhibitors may be more beneficial than tamoxifen when used as primary endocrine therapy in elderly patients. We aimed to retrospectively evaluate a series of elderly women with ER-positive breast cancer treated with primary letrozole therapy as sole therapy with a minimum of 5 years follow up. To identify possible predictive biomarkers a pilot immunohistochemical analysis was performed to assess the expression of PR, HER2, EGFR, BCL2 and p53. A total of 45 women, aged more than 70 years with a diagnosis of ER-positive breast cancer that was treated with primary letrozole therapy were identified. A case note review was undertaken to obtain clinical information. Formalin fixed paraffin embedded tumour tissue from diagnostic core biopsies was available for all patients. Immunohistochemical analysis was performed to establish the protein expression status of p53, PR, HER2, EGFR and BCL2. The mean age of the 45 patients was 87 years (range 70â101). Clinical benefit was seen in 60% of the patients. Median progression free survival was 53 months (95% CI â 34â72) and the median time to progression was 43 months (95% CI â 22â64). BCL2 was expressed in 45/45 (100%); PR in 38/45 (84%); EGFR in 13/45 (28%); HER2 in 9/45 (20%) and p53 in 5/45 (11%) of tissue samples. Positive expression of p53 was associated with poor progression free survival (p = 0.03) in this pilot study. This study demonstrates that letrozole as sole treatment appears to be a suitable treatment option for elderly patients with ER-positive breast cancer who are not fit for, or decline, surgery. The analysis of p53 in a larger study is warranted in order to assess its role as a biomarker in this patient group
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