10,411 research outputs found

    Sheepskin or Prozac: The Causal Effect of Education on Mental Health

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    Mental illness is associated with large costs to individuals and society. Education improves various health outcomes but little work has been done on mental illness. To obtain unbiased estimates of the effect of education on mental health, we rely on a rich longitudinal dataset that contains health information from childhood to adulthood and thus allow us to control for fixed effects in mental health. We measure two health outcomes: malaise score and depression and estimate the extensive and intensive margins of education on mental health using various estimators. For all estimators, accounting for the endogeneity of education augments its protecting effect on mental health. We find that the effect of education is greater at mid-level of qualifications, for women and for individuals at greater risk of mental illness. The effects of education are observed at all ages, additionally education also reduces the transition to depression. These results suggest substantial returns to education in term of improved mental health.Returns to education, mental health

    Agricultural aviation research

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    A compilation of papers, comments, and results is provided during a workshop session. The purpose of the workshop was to review and evaluate the current state of the art of agricultural aviation, to identify and rank potentially productive short and long range research and development areas, and to strengthen communications between research scientists and engineers involved in agricultural research. Approximately 71 individuals actively engaged in agricultural aviation research were invited to participate in the workshop. These were persons familiar with problems related to agricultural aviation and processing expertise which are of value for identifying and proposing beneficial research

    Carbide factor predicts rolling-element bearing fatigue life

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    Analysis was made to determine correlation between number and size of carbide particles and rolling-element fatigue. Correlation was established, and carbide factor was derived that can be used to predict fatigue life more effectively than such variables as heat treatment, chemical composition, and hardening mechanism

    Emission processes and dynamics of hot gases in astrophysics

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    A detailed model was developed for Kepler's supernova remnant (SNR). Observations of the SNR revealed a strong interaction with the surrounding circumstellar medium, which was studied through both analytical and numerical calculations. Effects were studied of electron thermal conduction on the structure of radiative interstellar shock waves. An explanation is sought for the observed line emission from metal rich ejecta in SNR, incorporating atomic data. Light echoes around SN 1987A was also studied. Analysis of infrared and scattered circumstellar light echoes was accomplished with early observations to set limits on the mass of circumstellar dust. Work was completed on the emission from heavy element gas ejected in the supernova explosion of massive stars. It was assumed that a radioactive energy source was present and calculated the detailed heating and ionization of the gas. The evolution was studied of SNR in the very high pressure environment of a starburst galaxy

    Study of hot hardness characteristics of tool steels

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    Hardness measurements of tool steel materials in electric furnace at elevated temperatures and low oxygen environment are discussed. Development of equation to predict short term hardness as function of intial room temperature hardness of steel is reported. Types of steel involved in the process are identified

    The Orbital Light Curve of Aquila X-1

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    We obtained R- and I-band CCD photometry of the soft X-ray transient/neutron- star binary Aql X-1 in 1998 June while it was at quiescence. We find that its light curve is dominated by ellipsoidal variations, although the ellipsoidal variations are severely distorted and have unequal maxima. After we correct for the contaminating flux from a field star located only 0.46" away, the peak-to-peak amplitude of the modulation is ~0.25 mag in the R band, which requires the orbital inclination to be greater than 36 degrees. The orbital period we measure is consistent with the 18.95 h period measured by Chevalier & Ilovaisky (1998). During its outbursts the light curve of Aql X-1 becomes single humped. The outburst light curve observed by Garcia et al. (1999) agrees in phase with our quiescent light curve. We show that the single humped variation is caused by a ``reflection effect,'' that is, by heating of the side of the secondary star facing towards the neutron star.Comment: 18 manuscript pages, 7 figures; accepted by A

    When is one kidney not enough?

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    Most renal failure in children results from congenital anomalies of the kidney and urinary tract (CAKUTs). Sanna-Cherchi et al. predict that by 30 years of age, nearly 50% of patients with a solitary kidney would be receiving dialysis. This outcome differs markedly from that of renal-transplant donors, who have no increased risk for renal failure. Because morbidity from CAKUTs may not develop until adulthood, these patients should be closely followed throughout life

    Short-term hot hardness characteristics of rolling-element steels

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    Short-term hot hardness studies were performed with five vacuum-melted steels at temperatures from 294 to 887 K (70 to 1140 F). Based upon a minimum Rockwell C hardness of 58, the temperature limitation on all materials studied was dependent on the initial room temperature hardness and the tempering temperature of each material. For the same room temperature hardness, the short-term hot hardness characteristics were identical and independent of material composition. An equation was developed to predict the short-term hardness at temperature as a function of initial room temperature hardness for AISI 52100, as well as the high-speed tool steels
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