843 research outputs found
Psychological distress, physical illness, and risk of coronary heart disease
Study objective: The aims of this study are to confirm the association between psychological distress and coronary heart disease (CHD) using an epidemiological community study with hospital admissions data and to examine if any association is explained by existing illness.
Design: Prospective cohort study modelling the association between psychological distress, measured using the 30 item general health questionnaire (GHQ), and hospital admissions data for CHD (ICD 410â414), using proportional hazards modelling adjusted for sociodemographic, CHD risk factors, and angina, bronchitis, diabetes, ischaemia, and stroke.
Setting: Two suburbs of Glasgow, Renfrew and Paisley, in Scotland.
Participants: 6575 men and women aged 45â64 years from Paisley.
Main: results: Five year CHD risk in distressed men compared with non-distressed men was 1.78 (95% confidence intervals (CI), 1.15 to 2.75) in age adjusted analysis, 1.78 (95% CI, 1.14 to 2.79) with sociodemographic and CHD risk factor adjustment, and 1.61 (95% CI 1.02 to 2.55) with additional adjustment for existing illness. Psychological distress was unrelated to five year CHD risk in women. In further analysis, compared with healthy, non-distressed men, distressed physically ill men had a greater risk of CHD than non-distressed physically ill men, a relative risk of 4.01 (95% CI 2.42 to 6.66) compared with 2.12 (95% CI 1.35 to 3.32).
Conclusion: The association of psychological distress with an increased risk of five year CHD risk in men could be a function of baseline physical illness but an effect independent of physical illness cannot be ruled out. Its presence among physically ill men greatly increases CHD risk
Village economies and the structure of extended family networks
This paper documents how the structure of extended family networks in rural Mexico relates to the poverty and inequality of the village of residence. Using the Hispanic naming convention, we construct within-village extended family networks in 504 poor rural villages. Family networks are larger (both in the number of members and as a share of the village population) and out-migration is lower the poorer and the less unequal the village of residence. Our results are consistent with the extended family being a source of informal insurance to its members
Family networks and school enrolment: evidence from a randomized social experiment
We present evidence on whether and how a householdâs behavior is influenced by the
presence and characteristics of its extended family. Using data from the PROGRESA
program in Mexico, we exploit information on the paternal and maternal surnames of
heads and spouses in conjunction with the Spanish naming convention to identify the inter
and intra generational family links of each household to others in the same village. We
then exploit the randomized research design of the PROGRESA evaluation data to identify
whether the treatment effects of PROGRESA transfers on secondary school enrolment
vary according to the characteristics of extended family. We find PROGRESA only raises
secondary enrolment among households that are embedded in a family network. Eligible
but isolated households do not respond. The mechanism through which the extended
family influences household schooling choices is the redistribution of resources within
the family network from eligibles that receive de facto unconditional cash transfers from
PROGRESA, towards eligibles on the margin of enrolling children into secondary school
Psychological distress and chronic obstructive pulmonary disease in the Renfrew and Paisley (MIDSPAN) study
Background: This study examined whether psychological distress might be a predictor of chronic obstructive pulmonary disease (COPD).
Method: The relation between psychological distress at baseline, measured by the general health questionnaire (GHQ), and chronic bronchitis three years later, as measured by the Medical Research Council (MRC) bronchitis questionnaire and forced expiratory flow in one second (FEV1), was examined in 1682 men and 2203 women from the Renfrew and Paisley (MIDSPAN) study. The analyses were run on men and women separately and adjustments were made for age, socioeconomic position, and lung function at baseline (FEV1). People with chronic diseases at baseline were then excluded to give a "healthy" baseline cohort. The effect of psychological distress on individual components of the MRC bronchitis questionnaire and FEV1 was also assessed.
Results: In multivariate analyses of the whole cohort baseline psychological distress in women was associated with reduced FEV1 at follow up (OR 1.31 95% CI 1.0 to 1.73) after adjustment. In women, in the healthy cohort, psychological distress was associated with chronic bronchitis (OR 2.00, 95% CI 1.16 to 3.46), symptoms of bronchial infection (OR 2.14, 95% CI 1.44 to 3.19), symptoms of breathlessness (OR 3.02, 95% CI 1.99 to 4.59), and reduced FEV1 (OR 1.62, 95% CI 1.13 to 2.32). In men psychological distress predicted symptoms of bronchial infection (OR 2.09, 95% CI 1.28 to 3.42).
Conclusion: This study supports research suggesting that psychological distress is associated with COPD and shows that psychological distress predicts COPD in women. The robustness of the association and the exact mechanism requires further investigation
Simulation and Optimization of Solar Desalination Plant Using Aspen Plus Simulation Software
AbstractOf the total global water, 94% is salt water from the oceans and the remaining 6% is fresh. The shortage of fresh water is a problem that has continued to challenge third world countries, and over time has become increasingly evident in developed nations around the globe. With a combination of contributing issues such as overpopulation and changes in weather and climatic conditions, the demand for alternate approaches to fresh potable water supply has increased dramatically. The paper develops a computational model to simulate the performance of a small scale solar desalination plant. The model is validated with experimental results found in the literature. The validated model is used to optimize the functional parameters of a desalination plant and in turn, enhance the recovery rate and product quality of the system. The model is suitable for brackish and seawater desalting applications specific to the climatic conditions of coastal Queensland, Australia. Aspen Plus is the process simulation software that was used for the modelling. The outcomes of the study is a validated process simulation model of a small scale solar desalination plant, optimization of this model for better utilization of current technologies and methods of improving performance, efficiency and recovery and reducing operational limitations
Consumption and Investment in Resource Pooling Family Networks
This paper examines a novel motive for resource pooling in family networks in rural economies: to relax credit constraints and facilitate investment in non-collateralizeable assets for which credit market imperfections are most binding. We thus complement established literatures examining risk-sharing motives for resource transfers within family networks, as well as motives based on kinship tax obligations. We do so exploiting the Progresa program data, in which family networks can be identified, households are subject to large exogenous resource inflows, and detailed responses on consumption and an array of investments can be tracked in a household panel over five years. We find that for every dollar that accrues to the family network through Progresa transfers, food consumption expenditures increase by around 65c/ for both households eligible for Progresa and ineligible members of the same family network. Hence the marginal propensity of families to invest/save out of every dollar is around .35, and we document how this is channelled towards easing credit constraints poorer network members face in financing non-collateralizable investments into their children's human capital. We show these consumption and investment benefits of being embedded within a family network are sustained five years after households first experience resource transfers from Progresa. Hence the interplay between resource inflows and resource pooling by family networks can place network members on sustained paths out of poverty
Molecular diversity at QTLs for pre-harvest sprouting resistance in spring wheat using microsatellite markers
Ab Initio Structural Studies of Cyclobutylmethyl Cations: Effect of Fluoroalkyl Groups on the Relative Stability of the Carbocations
Ab initio calculations at MP2/cc-pVTZ level show that the trifluoromethyl group has a strong destabilizing effect on the nonclassical, Ï-bridged cyclobutylmethyl cations. The GIAO-MP2 derived 13C NMR chemical shifts indicate substantial charge delocalization from the neighboring cyclobutyl ring for carbocations with an α-fluorolkyl group as compared to the 1-cyclobutylethyl cation, and this enhanced charge delocalization in case of the α-(trifluoromethyl)cyclobutylmethyl cation would lead to the ring-opening rearrangement to form the relatively more stable nonclassical primary cyclobutylmethyl cation, in which the carbocation center is farthest from the strongly electron-withdrawing trifluoromethyl group
Feasibility Study of a Bi-directional Centrifugal Pump for DBT class 45 CST Gearbox Used in Underground Coal mining Operation
This paper presents a feasibility study of using a bi-directional centrifugal pump into DBTâs Series 45 CST gearbox. The suitability of other pumps for cooling and the design of a new symmetrical centrifugal pump that would be suited to the series 45 CST gearbox have been reviewed with financial versus functionality and usability. The analysis and results of this study indicate that by introducing the newly designed bi-directional pump, DBT may save over 1850 per gearbox which is about a 26% saving on the current set-up, and thus bi-directional pump is reasonably feasible
Pyrolysis of municipal green waste: a modelling, simulation and experimental analysis
Pyrolysis is the thermo-chemical conversion of carbonaceous feedstock in the absence of oxygen to produce bio-fuel (bio-oil, bio-char and syn-gas). Bio-fuel production from municipal green waste (MGW) through the pyrolysis process has attracted considerable attention recently in the renewable energy sector because it can reduce greenhouse gas emissions and contribute to energy security. This study analyses properties of MGW feedstock available in Rockhampton city of Central Queensland, Australia, and presents an experimental investigation of producing bio-fuel from that MGW through the pyrolysis process using a short sealed rotary furnace. It was found from the experiment that about 19.97% bio-oil, 40.83% bio-char and 29.77% syn-gas can be produced from the MGW. Then, a four-stage steady state simulation model is developed for pyrolysis process performance simulation using Aspen Plus software. In the first stage, the moisture content of the MGW feed is reduced. In the second stage, the MGW is decomposed according to its elemental constituents. In the third stage, condensate material is separated and, finally, the pyrolysis reactions are modelled using the Gibbs free energy minimisation approach. The MGW\u27s ultimate and proximate analysis data were used in the Aspen Plus simulation as input parameters. The model is validated with experimentally measured data. A good agreement between simulation and experimental results was found. More specifically, the variation of modelling and experimental elemental compositions of the MGW was found to be 7.3% for carbon, 15.82% for hydrogen, 7.04% for nitrogen and 5.56% for sulphur. The validated model is used to optimise the biofuel production from the MGW as a function of operating variables such as temperature, moisture content, particle size and process heat air-fuel ratio. The modelling and optimisation results are presented, analysed and discussed
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