The Effect of High School Matriculation Awards: Evidence from Randomized Trials

In Israel, as in many other countries, a high school matriculation certificate is required by universities and some jobs. In spite of the certificate's value, Israeli society is marked by vast differences in matriculation rates by region and socioeconomic status. We attempted to increase the likelihood of matriculation among low-achieving students by offering substantial cash incentives in two demonstration programs. As a theoretical matter, cash incentives may be helpful if low-achieving students reduce investment in schooling because of high discount rates, part-time work, or face peer pressure not to study. A small pilot program selected individual students within schools for treatment, with treatment status determined by previous test scores and a partially randomized cutoff for low socioeconomic status. In a larger follow-up program, entire schools were randomly selected for treatment and the program operated with the cooperation of principals and teachers. The results suggest the Achievement Awards program that randomized treatment at the school level raised matriculation rates, while the student-based program did not.

Determining Pesticide and Nitrate Levels in Spring Water in Northwest Arkansas

Occurrences of pesticides in our nations ground water are on the rise. As states become aware of this problem and begin monitoring programs, incidence of contamination will probably increase. Since the problem of pesticides in groundwater is relatively new, little research has centered on the fate of pesticides after they reach the groundwater environment. In Northwest Arkansas efforts to monitor groundwater for pesticides have been small. Twenty-five springs in Northwest Arkansas were sampled in the fall of 1988, and spring of 1989. Analysis for atrazine, alachlor, metolachlor, diuron, and simazine in spring water was preformed using gas liquid chromatography and high performance liquid chromatography. No detectable residues of any of the selected pesticides were found. Northwest Arkansas is a leader in poultry production. Much of the manure from poultry houses is spread on the sourounding pastures. As this litter decomposes nitrates and phosphates are released. Nitrate and phosphate concentrations were also determined on water from the spring samples. No spring exceeded the EPA\u27s limit of 45 mg/L for nitrate in drinking water. The highest concentration for phosphate in any spring was 1.05 mg/L

Minimizing the Potential for Groundwater Contamination from Agricultural Point Sources

An activated charcoal filtration unit was designed to remove pesticides from leftover pesticide solutions and rinsates generated under farm-like conditions. The system, fabricated for less than $1400 using readily available components, effectively removed the pesticides atrazine, benomyl, carbaryl, fluometuron, metolachlor, and trifluralin from wastewater generated on the University of Arkansas Agronomy Farm located in Fayetteville, AR. A total of 2253 L of wastewater were treated using the system. Of these 1768 L were generated from washing out the spray tank (rinsates) while 485 L stemmed from leftover pesticide solutions that were mixed, but not applied. Typical initial pesticide concentrations in the wastewater were on the order of 500 to 1000 parts per million (ppm). The final pesticide concentrations remaining after charcoal filtration were generally less than 10 ppm. Approximately 1514 L of wastewater was treated with 23 kg of charcoal before the charcoal was replaced. This resulted in an estimated pesticide loading rate on the charcoal of 0.05 to 0.10 kg pesticide active ingredient per kg activated charcoal. Incubation of alachlor-treated charcoal with a mixed culture of microorganisms resulted in approximately a 30% loss of alachlor after 21 d. These results suggest that on-site degradation of spent charcoal may be a feasible alternative to incineration, however more research is needed to fully determine its potential. A reduced adsorption of methylene blue dye with increasing amounts of trifluralin sorbed to charcoal occurred. Activated charcoal treated with 222 mg/g trifluralin sorbed only 19% of the amount sorbed by the control with no trifluralin present. These results suggest that methylene blue or other dyes might be used to indicate the remaining adsorptive capacity of a charcoal used for removing pesticides from wastewater

Does Immigration Affect the Long-Term Educational Outcomes of Natives? Quasi-Experimental Evidence

This paper uses the mass migration wave to Israel in the 1990s to examine the impact of immigrant concentration in elementary school on the long-term academic outcomes of native students in high school. To identify the causal effect of immigrant children on their peers, we exploit random variation in the number of immigrants across grades within the same school. The results suggest that the overall presence of immigrants had essentially no effect on the quality of the high school attended by native Israelis and on dropout rates, and at most a mild negative effect on high school matriculation rates. However, when we break up the sample by parents' education and by ethnic origin, we find that disadvantaged children were more likely to have been adversely affected by a higher immigrant concentration in elementary school. Focusing on the impact of Ethiopian immigrants who are from a much lower socio-economic background, we find stronger evidence of adverse effects, especially for disadvantaged students and in classes where immigrant concentration was particularly high.

Maimonides rule redux

We use Maimonides' rule as an instrument for class size in large Israeli samples from 2002–2011. In contrast with Angrist and Lavy (1999), newer estimates show no evidence of class size effects. The new data also reveal enrollment manipulation near Maimonides cutoffs. A modified rule that uses birthdays to impute enrollment circumvents manipulation while still generating precisely estimated zeros. In both old and new data, Maimonides' rule is unrelated to socioeconomic characteristics conditional on a few controls. Enrollment manipulation therefore appears to be innocuous. We briefly discuss possible explanations for the disappearance of Israeli class size effects since the early 1990s

Analyses of Groundwater for Trace Levels of Pesticides

Agricultural production is a major source of revenue in Arkansas. In order to increase productivity, it has been necessary to rely increasingly on the use of pesticides and irrigation water. In the last 15 years several states have reported finding pesticides in groundwater as a result of normal agricultural practices. Since almost half of the population also relies on groundwater as their source of drinking water, it is necessary to conduct research as to ascertain the presence or absence of commonly used pesticides in groundwater. Multi residue analytical techniques were developed for the analysis of acifluorfen, alachlor, atrazine, cyanazine, diuron, fluometuron, linuron, metolachlor and propanil from groundwater, by either GLC or HPLC. Analytical sensitivities ranged from 1 to 5 ppb. Groundwater samples were collected from three areas of southeastern Arkansas that are under heavy agricultural production. Samples were collected directly from irrigation wells just prior to and during the peak of the irrigation season and will be compared to determine whether any temporal differences exist. To-date, over 500 samples have been analyzed. No positive finding for any pesticide has been shown

Sixty Years after the Magic Carpet Ride: The Long-Run Effect of the Early Childhood Environment on Social and Economic Outcomes

This paper estimates the effect of the childhood environment on a large array of social and economic outcomes lasting almost 60 years, for both the affected cohorts and for their children. To do this, we exploit a natural experiment provided by the 1949 Magic Carpet operation, where over 50,000 Yemenite immigrants were airlifted to Israel. The Yemenites, who lacked any formal schooling or knowledge of a western-style culture or bureaucracy, believed that they were being "redeemed," and put their trust in the Israeli authorities to make decisions about where they should go and what they should do. As a result, they were scattered across the country in essentially a random fashion, and as we show, the environmental conditions faced by immigrant children were not correlated with other factors that affected the long-term outcomes of individuals. We construct three summary measures of the childhood environment: 1) whether the home had running water, sanitation and electricity; 2) whether the locality of residence was in an urban environment with a good economic infrastructure; and 3) whether the locality of residence was a Yemenite enclave. We find that children who were placed in a better environment (i.e. with better sanitary and infrastructure conditions) were more likely to obtain higher education, marry at an older age, have fewer children, and work at age 55. They were also more likely to be assimilated into Israeli society, to be less religious, and have more worldly tastes in music and food. The estimated effects are much more pronounced for women than for men. We find weaker and somewhat mixed effects on health outcomes, and no effect on political views. We do find an effect on the next generation – children who lived in a better environment grew up to have children who achieved higher educational attainment.

Geographical Differences in the Forefoot Morphology – A Comparative Radiological Study of Feet in Malawi and UK

Background: Many skeletal morphological differences between populations have been reported with possible but unproven clinical importance. This study was aimed at identifying the normal radiographic findings and measurements seen in patients from Southern Africa and compares them to a European population’s values.Methods: AP foot radiographs of 40 adults from Blantyre, Malawi were compared with those of 40 adults from London, UK. For each patient, measurements were taken of: 1st and 2nd metatarsal lengths, the 1st/2nd intermetatarsal angle, the 1st metatarso- phalangeal angle (the ‘bunion’ angle), and the 2nd metatarsal mortice joint medial and lateral depths.Results: Our results show an increased 1st/2nd metatarsal angle in Malawian feet, but a reduced ‘bunion’ angle. We also found the second metatarsal length to be longer relative to the first in the Malawian foot, and the 2nd metatarsal base to be significantly more covered by its mortice than in UK feet.Conclusion: This racial anatomical variation may convey more stability and less risk of a Lisfranc dislocation. It is also important to be aware of the normal range of these values when considering the need for forefoot arthroplasty procedures

The Effect of Teen Childbearing and Single Parenthood on Childhood Disabilities and Progress in School

be responsible for poor health and low levels of schooling among the children of young mothers. This paper uses special disability and grade repetition questions from the school enrollment supplement to the 1992 Current Population Survey to estimate the effect of maternal age and single parenthood on children's disability status and school progress. Our results suggest that there is little association between maternal age at birth and children's disabilities. But the children of teen mothers are much more likely to repeat one or more grades than other children, and within-household estimates of this relationship are even larger than OLS estimates. The grade repetition findings from the CPS are replicated using a smaller sample from the National Longitudinal Survey of Youth. Another finding of interest is that having a father in the household is associated with lower disability prevalence and fewer grade repetitions. But many of the effects of single parenthood on disability, as well as the effect on grade repetition, appear to be explained by higher incomes in two-parent families.

Using Maimonides' Rule to Estimate the Effect of Class Size on Student Achievement

The effect of class size on student achievement has long been of concern to educators, parents, and scholars. In Israeli public schools today, class size is partly determined using a rule proposed by Maimonides in the 12th century. This rule induces a nonlinear and non-monotonic relationship between enroll- ment size and class size. We use this relationship to construct instrumental variables estimates of the effect of class size on the test scores of Israeli 4th and 5th graders in 1991 and 3rd graders in 1992. Because the up-and-down pattern in class size induced by Maimonides' rule matches a similar pattern in test scores, the rule provides a credible source of exogenous variation for investigation of the causal effect of class size on student achievement. Our use of Maimonides' rule can be viewed as an application of Campbell's (1969) regression-discontinuity design to the class size question. The results of this application show that reductions in class size induce a significant increase in reading and math scores for 5th graders and a smaller increase in reading scores for 4th graders. In contrast, there is little evidence of any association between class size and the test scores of 3rd graders, although this finding may result from problems with the 1992 wave of the testing program. The estimates also suggest that the gains from small classes are largest for students from disadvantaged backgrounds. Besides being of metho- dological interest and providing new evidence on the class size question, these findings are of immediate policy interest in Israel where legislation to reduce the maximum class size is pending.