Stress among Isfahan medical sciences students

Background: This study was undertaken to determine the prevalence of psychological stress among Isfahan medical sciences students. Methods: Cross-sectional, questionnaire-based survey was carried out among the 387 medical sciences students (medicine, pharmacy, and dentistry) of Isfahan, Iran through census. In academic year 2010-2011, Kessler-10 questionnaire was given to the students a month before semester examinations. Scores �20 were considered as indicative of positive stress symptoms. Results: The overall prevalence of stress among medical sciences students was found to be about 76.1%. The prevalence of stress among medicine students was 22.7% mild, 23% moderate and 21.4% severe while 32.8% showed no stress. The prevalence of stress among pharmacy students was 22.22%, 22.22%, 26.19%, and 29.36% mild, moderate, and severe and no stress, respectively. The prevalence of stress among dentistry students was 25% mild, 27% moderate, and 10% severe while 37.5% showed no stress. The prevalence of stress was higher (70.6%) in pharmacy students when compared with medicine (66.1%) and dentistry (62.5%) students. The odds of student having stress is higher in dentistry students (OR: 1.44, P= 0.33), where as the odds are decreasing in pharmacy student (OR: 1.16, P= 0.66). There is no statistically significant association between gender, ages, and term and having stress symptoms. Conclusions: The high level of stress necessitates interventions like social and psychological support to improve the student's well-being. A prospective study is needed to study the association of psychological morbidity with sources of stress and coping strategies

Automatic detection of coronaries ostia in computed tomography angiography volume data

Background: Heart coronaries emerge from the ascending aorta lateral sides from two points called the coronaries ostia. To automatically segment the heart coronaries; there must be a starting point (seed) for the segmentation. In this paper we present a fully automatic approach to segment the coronaries ostia towards automatic seeding for heart coronaries segmentation.Methods: Our algorithm takes as an input a CTA volume of segmented aorta cross sections that represents our region of interest. Then the ostia detection algorithm traverses that volume looking for the ostia points in an automatic fashion. The proposed algorithm depends on the anatomical features of the ostia. The main anatomic feature of the ostia is that it appears like a curvature or corner on the segmented ascending aorta cross section. Therefore we adopted in our methodology a modified version of Harris Corner Detection; besides inducing some anatomical features of the ostia location with respect to the aortic valve.Results: The proposed algorithm is tested and validated on the computed tomography angiography database provided by the Rotterdam coronary artery algorithm evaluation framework. The proposed automatic ostia detection algorithm succeeded to detect both ostia points in all the test cases. Also, the detected ostia points’ coordinates are validated versus a ground truth provided by the same framework with deviation between the results of the detection process and the ground truth having a min of 0 pixels and a max of 10 pixels for all test cases.Conclusions: Thus the proposed algorithm gives accurate results in comparison with the ground truth, which proves the efficiency of the proposed algorithm and its applicability to be extended as a seed for heart coronaries segmentation

Aerothermal modeling program, phase 2. Element C: Fuel injector-air swirl characterization

The main objectives of the NASA-sponsored Aerothermal Modeling Program, Phase 2--Element C, are experimental evaluation of the air swirler interaction with a fuel injector in a simulated combustor chamber, assessment of the current two-phase models, and verification of the improved spray evaporation/dispersion models. This experimental and numerical program consists of five major tasks. Brief descriptions of the five tasks are given

Aerothermal modeling program, Phase 2, Element C: Fuel injector-air swirl characterization

The main objectives of the NASA sponsored Aerothermal Modeling Program, Phase 2, Element C, are to collect benchmark quality data to quantify the fuel spray interaction with the turbulent swirling flows and to validate current and advanced two phase flow models. The technical tasks involved in this effort are discussed

Missing at random assumption made more plausible: evidence from the 1958 British birth cohort

Objective: Non-response is unavoidable in longitudinal surveys. The consequences are lower statistical power and the potential for bias. We implemented a systematic data-driven approach to identify predictors of non-response in the National Child Development Study (NCDS; 1958 British birth cohort). Such variables can help make the missing at random assumption more plausible, which has implications for the handling of missing data. / Study Design and Setting: We identified predictors of non-response using data from the 11 sweeps (birth to age 55) of the NCDS (n = 17,415), employing parametric regressions and the LASSO for variable selection. / Results: Disadvantaged socio-economic background in childhood, worse mental health and lower cognitive ability in early life, and lack of civic and social participation in adulthood were consistently associated with non-response. Using this information, along with other data from NCDS, we were able to replicate the “population distribution” of educational attainment and marital status (derived from external data), and the original distributions of key early life characteristics. / Conclusion: The identified predictors of non-response have the potential to improve the plausibility of the missing at random assumption. They can be straightforwardly used as “auxiliary variables” in analyses with principled methods to reduce bias due to missing data

Simulation of Chlorine Decay in Water Distribution Networks Using EPANET – Case Study

Deterioration of water quality in distribution networks has a great impact on human health and public acceptance of tap water reaching them. Residual chlorine should be maintained through network pipes to prevent contamination and microbial regrowth. This paper investigates the ability of EPANET 2.0, a free software developed by United States Environment Protection Agency (USEPA), to simulate residual chlorine decay through water networks, taking water-age analyses into consideration, and assesses the feasibility of using it as a measuring and controlling tool to estimate and predict chlorine concentration at different water network points. A study was performed on drinking water network of 6th of October city, where field measurements were done, while data required as program inputs were taken from the daily records of the 6th of October and El-Shaikh Zayed WTPs. The network model was calibrated to minimize error in program results. Errors were evaluated using statistical analyses. The calculated concentrations by the calibrated model were very close to the actual concentrations measured in field at different sampling points for different sampling days. Moreover, EPANET showed that for the water network concerned in this study, chlorine concentrations at network extremities did not recede 0.5 mg/l, the minimum allowable limit established in the Egyptian Code of Practice (ECP), even for those points having water age greater than 24 hours. Keywords: chlorine decay, water quality, water distribution networks, EPANET, water-ag

Synthesis and Characterization of Chitosan Based Catalyst for Catalysis Applications

In this research, chitosan-based catalyst synthesis and characterization was investigated for different application in catalysis as chitosan-based catalyst was combined with metal oxides in order to be used in dye removal of methyl orange (MO). Diluted acetic acid was used to dissolve chitosan then different percentages for metallic ions were mixed with diluted chitosan and then, 500 µL were added to the sample to reduce the metal salts then, microwave was used to heat the mixture for 5 minutes and then dried at 80-100 °C. Finally, X- ray diffraction was used to confirm the catalyst prepared. The aim of this research is to investigate and explore the feasibility of chitosan/metallic ions composite for removing MO from aqueous solutions. The influence of several operating parameters for adsorption of MO, such as contact time, temperature and ph

Sustainable Hydrogen Production via Sorption Enhanced Reforming of Complex Biorefinery Side Streams in a Fixed Bed Adiabatic Reactor

In this work, sorption enhanced steam reforming is explored as a potential solution for the valorization of gaseous streams recovered from biorefinery hydrogenation processes. The hydrogen content of such streams limits the hydrocarbon conversion in conventional steam reforming due to thermodynamic and kinetic constraints. A previously developed 1D dynamic heterogeneous model of an adiabatic reactor was thus applied to evaluate the effect of H-2 dilution on the performance indicators of the sorption enhanced reforming process. The mathematical model analysis highlights that despite of CO2 capture by the sorbent favorably modifies the thermodynamics of syngas production, H-2 dilution worsens the performance of the sorption enhanced reforming of model H-2/CH4 streams with respect to pure CH4. Results show a drop of 17% for CH4 conversion and a reduction of 15.4% of the captured CO2 on passing from pure methane to a H-2/CH4 feed with a 40/60 molar ratio. However, on increasing the heat capacity of the bed, by replacing part of the sorbent with an inert heat carrier, better performances are calculated for the H-2/CH4 feed matching the pure CH4 case. The presence of C2+ hydrocarbons is assessed as well and the results show a significant improvement in the reformer's performance; in the case of a stream composed of H-2/CH4/C3H8 with a molar ratio 40/45/15, the total hydrocarbon conversion grows to 92.8%, CO2 capture ratio to 82.6%, and H-2 purity to 95.6%. The positive effect is associated with thermal factors that promote the reaction kinetics. Thus, the suitability of the sorption enhanced reforming technology to H-2-rich and C-poor streams is strictly composition dependent; by cofeeding of C2+ hydrocarbons, the process turns into a remarkable solution for converting gaseous streams in pure H-2