Who Marries Differently-Aged Spouses?: Earnings, Ability and Appearance

In direct contrast to conventional wisdom and most economic models of gender differences in age of marriage, we present robust evidence that men and women who are married to differently-aged spouses are negatively selected. Earnings analysis of married couples in the 1970, 1980, 1990 and 2000 Decennial Censuses finds that male earnings decrease with within-couple age difference, regardless of whether the man is older or younger than his wife. In contrast, female earnings increase with within-couple age difference. We argue and present evidence that women in differently-aged couples have higher earnings not because of positive selection, but because their hours of work increase in response to partnering with a lower earning man. We test for negative selection into differently-aged couples using three measures: average earnings per hour in occupation using Census data, cognitive skills assessments from the National Longitudinal Survey of Youth 1979 cohort (NLSY79), and measures of physical appearance from the National Longitudinal Study of Adolescent Health (Add Health). The point estimates indicate negative selection on all of these characteristics, although statistical significance varies by outcome and sample.marital sorting, occupational choice, non-labor market outcomes

The Effect of Prenatal Stress on Birth Weight: Evidence from the al-Aqsa Intifada

No previous study has attempted to estimate the effect of intrauterine exposure to armed conflict, a potential source of stress, on pregnancy outcomes. Drawing on data from the 2004 Palestinian Demographic and Health Survey, we examine the relationship between fatalities caused by Israeli security forces (a measure of conflict intensity) and birth weight. Our estimates suggest that first-trimester fatalities are positively related to the probability that a child weighed less than 2,500 grams at birth. This result is consistent with medical studies showing a strong negative correlation between self-reported stress during the first trimester of pregnancy and birth weight.Birth weight, prenatal stress, Israeli-Palestinian conflict

The Effect of Prenatal Stress on Birth Weight: Evidence from the al-Aqsa Intifada

No previous study has attempted to estimate the effect of intrauterine exposure to armed conflict, a potential source of stress, on pregnancy outcomes. Drawing on data from the 2004 Palestinian Demographic and Health Survey, we examine the relationship between fatalities caused by Israeli security forces (a measure of conflict intensity) and birth weight. Our estimates suggest that first-trimester fatalities are positively related to the probability that a child weighed less than 2,500 grams at birth. This result is consistent with medical studies showing a strong negative correlation between self-reported stress during the first trimester of pregnancy and birth weight.birth weight, prenatal stress, Israeli-Palestinian conflict

Does Employer Learning Vary by Occupation?

Models in which employers learn about the productivity of young workers, such as Altonji and Pierret (2001), have two principal implications: First, the distribution of wages becomes more dispersed as a cohort of workers gains experience; second, the coefficient on a variable that employers initially do not observe, such as the Armed Forces Qualification Test (AFQT) score, grows with experience. If employers' learning varies significantly across occupations, both of these indicators of learning should covary positively across groups defined by a worker's occupational assignment at labor market entry. This paper tests this implication of the employer learning model using data from the NLSY and CPS. I find that occupations with high growth in the variance of residual wages over the first ten years of the worker's career are also the occupations with high growth in the AFQT coefficient, confirming the learning perspective. Interestingly, occupations that my analysis characterizes as having a low level of employer learning are not occupations where employers know little about the worker after ten years of experience; instead they appear to be occupations where employers have already learned about the worker's AFQT score at the time of hire. I provide several pieces of evidence that occupational assignment affects the learning process independently from education and that the results are not driven by workers' occupational mobility.Wage Dynamics, Occupational Choice, Earnings Inequality

Fitness Characteristics of Jordanian Emergency Medical Technicians

Introduction: Emergency medical technicians (EMTs) should be always prepared to deal with the stressful condition of treating patients with serious physical and emotional injuries. Given that EMTs consider safety the first priority, they must pay adequate attention to their own physical well-being and fitness to practice. Objective: The present study was conducted to analyze the fitness of Jordanian EMTs. Method: The present prospective study was conducted to evaluate the well-being of Jordanian paramedics. The survey was designed using Google forms, which were completed by the participants. The data collection tools comprised an already-designed checklist, including items such as age, gender as well as height and weight, which are used for calculating body mass index (BMI). In addition, the presence of chronic diseases such as hypertension, diabetes mellitus, renal failure and cardiorespiratory diseases as well as the history of surgeries and disabilities were investigated. The participants were also asked about their smoking status and other health-related habits. Results: Out of 115 surveys conducted, 7 were discarded owing to loss of information or making completion mistakes. Out of the remaining 108 respondents, 82 (75.9%) were male and below 10% were over the age of 30 years. BMI was over 25 in 40.7% of the respondents, and only 4 (3.7%) had chronic diseases. Moreover, 46 (42.6%) respondents were smokers, and only 30 (27.8%) performed regular exercise. Conclusion: The present findings suggest health problems in a small percentage of the EMTs, potentially due to the appropriate support provided by the employers or university authorities in this regard. The major health problem was overweight and unhealthy lifestyle, including smoking and not doing regular exercise

Effect of drip irrigation circuits design and lateral line length on: II-flow velocity and velocity head

The objectives of the work were to study the effect of drip irrigation circuits (DIC) and lateral lines lengths (LLL) on: Flow velocity (FV) and velocity head (VH). Laboratory tests were con- ducted at Irrigation Devices and Equipments Tests Laboratory, Agricultural Engineering Research Institute, Agriculture Research Center, Giza, Egypt. The experimental design of laboratory experiments was split in randomized complete block design with three replicates. Laboratory tests carried out on three irrigation lateral lines 40, 60, 80 m (LLL1, LLL2; LLL3) under the following three drip irrigation circuits (DIC): a) one manifold for lateral lines or closed circuits with one manifold of drip irrigation system (CM1DIS); b) closed circuits with two manifolds for lateral lines (CM2DIS), and c) traditional drip irrigation system (TDIS) as a control. Concerning FV values, DIC and LLL treatments could state in the following ascending orders: TDIS \u3c CM1DIS \u3c CM2DIS and LLL1 \u3c LLL2 \u3c LLL3, respectively. FV varied from 0.593 m·sec–1 to 1.376 m·sec–1. i.e. FV \u3c 5 ft·sec–1 and this is necessary to avoid the effect of water hammer in the main and sub-main lines, but in lateral line, it can cause silt and clay precipitation problems. The differences in FV among DIC and LLL were significant at the 1% level. The effect of interaction: DIC X LLL on FV values, were significant at the 1% level. The maximum and minimum values of FV were noticed in these interactions: CM2DIS X LLL3 and TDIS X LLL1, respectively. The following ascending orders TDIS \u3c CM1DIS \u3c CM2DIS and LLL1 \u3c LLL2 \u3c LLL3 expressed their effects on VH respectively. Differences in VH among DIC and/or LLL were significant at the 1% with few exceptions. The effects of interactions: DIC X LLL on VH were significant at the 1% level in some cases. The maximum and minimum values of VH were found in the interactions: CM2DIS X LLL3 and TDIS X LLL1, respectively

Effects of drip irrigation circuit design and lateral line lengths: I—On pressure and friction loss

Laboratory tests were conducted at the Irrigation Devices and Equipment’s Test Laboratory, Agricultural Engineering Research Institute, Agriculture Research Center, Giza, Egypt. The experimental design of laboratory experiments was split in randomized complete block design with three replicates. Laboratory tests carried out on three irrigation lateral lines of 40, 60, 80 m under the following three drip irrigation circuit (DIC) designs; 1) one manifold for lateral lines or closed circuits with one manifold of drip irrigation system (CM1DIS); 2) closed circuits with two manifolds for lateral lines (CM2DIS), and 3) traditional drip irrigation system (TDIS) as a control. The aims of the work were to study the effect of drip irrigation circuits (DIC) and lateral lines lengths (LLL; where): (LLL1 = 40 m, LLL2 = 60 m, and LLL3 = 80 m) on pressure head (PH) and friction loss (FL). Regarding to LLL and according to PH values, DIC designs could be ranked in the following ascending order: TDIS \u3c CM1DIS \u3c CM2DIS. The differences in PH among DIC de-signs were significant at the 1% level. The de-pressive effects of LLL on PH could be ranked in the following ascending order: LLL1 \u3c LLL2 ≤ LLL3. Differences in PH among LLL treatments were significant at the 1% level except that be-tween LLL2 and LLL3. The effects of interactions among: DIC × LLL on PH were significant at the 1% level with some exceptions. The highest value of PH (9.5 m) and the lowest one (6.05 m) were achieved in the interactions of CM2DIS × LLL1 and TDIS × LLL3, respectively. The shapes of the energy gradient lines were affected by DIC and LLL treatments used through their effect on ΔH/H ratio. However, they followed similar trends. According to the FL values, DIC and LLL treatments could be ranked in the following descending orders TDIS \u3e CM1DIS \u3e CM2DIS and LLL1 \u3e LLL2 \u3e LLL3. The differences in FL among DIC and LLL were significant and the effects of interactions among DIC × LLL on FL were significant at the 1% level. The maximum and mi- nimum values of FL were obtained in the inter-actions: TDIS × LLL3 and CM2DIS × LLL1, respectively. Therefore, the CM2DIS system is recommended for use where technically feasible

Performance of Water Desalination and Modern Irrigation Systems for Improving Water Productivity

Desalination is the process that is performed to remove excess salts from water to become potable or agriculture. This applied science is now concerned by many countries suffering from water shortage. Over the next ten years, this science is expected to grow significantly due to the expected water crises in many countries. The consumption of energy in the desalination process is one of the important problems and difficult obstacles that need to be overcome. The Egyptian water strategy should include increasing amount of desalinated water to more than 50%, especially since Egypt is in a very rich location in saltwater sources and they can be utilized to the maximum extent possible. The researchers have attempted to develop varieties of some traditional crops such as wheat, saline resistant to salinity using local selective ecotourism techniques and using genetic engineering through which saline-tolerant genes are added, but it can be said that so far these efforts have not resulted in the production of candidate seawater breeds The maximum salinity of irrigation water in the long term, even for the most salt-tolerant crops such as date palm, is still less than 5 mmol

Energy and water saving by using modified closed circuits of drip irrigation system

The aim of this research was determine the energy and water use efficiencies under the modification of closed circuit drip irrigation systems designs. Field experiments carried out on transgenic maize (GDH, LL3), (Zea Mays crop) under two types of closed circuits: a) One manifold for lateral lines or Closed circuits with One Manifold of Drip Irrigation System (CM1DIS); b) Closed circuits with Two Manifolds of Drip Irrigation System (CM2DIS), and c) Traditional Drip Irrigation System (TDIS) as a control. Three lengths of lateral lines were used, 40, 60, and 80 meters. PE tubes lateral lines: 16 mm diameter; 30 cm emitters distance, and GR built-in emitters 4 lph when operating pressure 1 bar under Two levels slope conditions 0% and 2%. Experiments were conducted at the Agric. Res. Fields., Soil and Plant & Agric. System Dept., Agric. Faculty, Southern Illinois University, Carbondale (SIUC), Illinois, USA. Under 0% level slope when using CM2DIS the increase percent of Energy Use Efficiency (EUE) were 32.27, 33.21, and 34.37% whereas with CM1DIS were 30.84, 28.96, and 27.45% On the other hand when level slope 2% were with CM2DIS 31.57, 33.14, and 34.25 while CM1DIS were 30.15, 28.98, and 27.53 under lateral lengths 40, 60 and 80 m respectively relative to TDIS. Water Use Efficiency (WUE) when level slope 0% under CM2DIS were 1.67, 1.18, and 0.87 kg/m3 compared to 1.65, 1.16, and 0.86 kg/m3 with CM1DIS and 1.35, 1.04, and 0.75 kg/m3 with TDIS whereas with level slope 2% when using CM2DIS were 1.76, 1.29, and 0.84 kg/m3 compared to 1.77, 1.30, and 0.87 kg/m3 with CM1DIS and 1.41, 1.12, and 0.76 kg/m3 (for lateral lengths 40, 60, and 80 meters respectively). Water saving percent varied widely within individual lateral lengths and between circuit types relative to TDIS. Under slope 0% level CM2DIS water saving percent values were 19.26, 12.48, and 14.03%; with CM1DIS they were 18.51, 10.50, and 12.78%; and under slope level 2% with CM2DIS they were 19.93, 13.26, and 10.38% and CM1DIS were 20.49, 13.96, and 13.23% (for lateral lengths 40, 60, 80 meters respectively). The energy use efficiency and water saving were observed under CM2DIS and CM1DIS when using the shortest lateral length 40 meters, then lateral length 60 meters, while the lowest value was observed when using lateral length 80 meters this result depends on the physical and hydraulic characteristics of the emitters, lateral line uniformity, and friction losses. CM2DIS was more energy use efficiency, EUE, water saving, and WUE than either CM1DIS or TDIS