16,510 research outputs found

    There Goes the Neighborhood? Estimates of the Impact of Crime Risk on Property Values From Megan's Laws

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    We combine data from the housing market with data from the North Carolina Sex Offender Registry to estimate how individuals value living in close proximity to a convicted criminal. We use the exact location of sex offenders to exploit variation in the threat of crime within small homogenous groupings of homes, and we use the timing of sex offenders' arrivals to control for baseline property values in the area. We find statistically and economically significant negative effects of sex offenders' locations that are extremely localized. Houses within a one-tenth mile area around the home of a sex offender fall by 4 percent on average (about 5,500).Wealsofindevidencethattheeffectvarieswithdistancewithinthisrangehousesnexttoanoffendersellforabout12percentlesswhilethoseatenthofamileawayormoreshownodecline.Wecombineourwillingnesstopayestimateswithdataonsexualcrimesagainstneighborstoestimatethecoststovictimsofsexualoffenses.Weestimatecostsofover5,500). We also find evidence that the effect varies with distance within this range -- houses next to an offender sell for about 12 percent less while those a tenth of a mile away or more show no decline. We combine our willingness-to-pay estimates with data on sexual crimes against neighbors to estimate the costs to victims of sexual offenses. We estimate costs of over 1 million per victim -- far in excess of estimates taken from the criminal justice literature. However, we cannot reject the alternative hypotheses that individuals overestimate the risk posed by offenders or view living near an offender as having costs exclusive of crime risk.

    The use and misuse of computers in education : evidence from a randomized experiment in Colombia

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    This paper presents the evaluation of the program Computers for Education. The program aims to integrate computers, donated by the private sector, into the teaching of language in public schools. The authors conduct a two-year randomized evaluation of the program using a sample of 97 schools and 5,201 children. Overall, the program seems to have had little effect on students'test scores and other outcomes. These results are consistent across grade levels, subjects, and gender. The main reason for these results seems to be the failure to incorporate the computers into the educational process. Although the program increased the number of computers in the treatment schools and provided training to the teachers on how to use the computers in their classrooms, surveys of both teachers and students suggest that teachers did not incorporate the computers into their curriculum.Tertiary Education,Primary Education,Secondary Education,Teaching and Learning,Education For All

    Summer Snapshot: Exploring the Impact of Higher Achievement's Year-Round Out-of-School-Time Program on Summer Learning

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    Assesses the impact of a multiyear, intensive, academically focused OST program for motivated but underserved middle school students on test scores, summer program participation, and summer learning loss. Examines contributing factors and implications

    Extended self-energy functional approach for strongly-correlated lattice bosons in the superfluid phase

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    Among the various numerical techniques to study the physics of strongly correlated quantum many-body systems, the self-energy functional approach (SFA) has become increasingly important. In its previous form, however, SFA is not applicable to Bose-Einstein condensation or superfluidity. In this paper we show how to overcome this shortcoming. To this end we identify an appropriate quantity, which we term DD, that represents the correlation correction of the condensate order parameter, as it does the self-energy for the Green's function. An appropriate functional is derived, which is stationary at the exact physical realizations of DD and of the self-energy. Its derivation is based on a functional-integral representation of the grand potential followed by an appropriate sequence of Legendre transformations. The approach is not perturbative and therefore applicable to a wide range of models with local interactions. We show that the variational cluster approach based on the extended self-energy functional is equivalent to the "pseudoparticle" approach introduced in Phys. Rev. B, 83, 134507 (2011). We present results for the superfluid density in the two-dimensional Bose-Hubbard model, which show a remarkable agreement with those of Quantum-Monte-Carlo calculations.Comment: 1 additional figure showing the region close to the tip of the Mott lobe, minor changes in the tex

    The effect of village-based schools: Evidence from a randomized controlled trial in Afghanistan

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    We conduct a randomized evaluation of the effect of village-based schools on children's academic performance using a sample of 31 villages and 1,490 children in rural northwestern Afghanistan. The program significantly increases enrollment and test scores among all children, eliminates the 21 percentage point gender disparity in enrollment, and dramatically reduces the disparity in test scores. The intervention increases formal school enrollment by 42 percentage points among all children and increases test scores by 0.51 standard deviations (1.2 standard deviations for children that enroll in school). While all students benefit, the effects accrue disproportionately to girls. Evidence suggests that the village-based schools provide a comparable education to traditional schools. Estimating the effects of distance on academic outcomes, children prove very sensitive: enrollment and test scores fall by 16 percentage points and 0.19 standard deviations per mile. Distance affects girls more than boys - girls' enrollment falls by 6 percentage points more per mile (19 percentage points total per mile) and their test scores fall by an additional 0.09 standard deviations (0.24 standard deviations total per mile)

    Distribution and Status of Ophiogomphus westfalli (Ondonata: Gomphidae) in Missouri and Arkansas

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    Ophiogomphus westfalli is endemic to the Interior Highlands (Ozark Plateaus and Ouachita Mountains), in Missouri, Arkansas and southeastern Kansas. First described in 1985, its life history is still little known. Prior to 1997, this species was known from only six sites in Missouri and 10 in Arkansas. From late May through late July in both 1999 and 2000 we surveyed 49 sites, three of them twice each, on Missouri Ozark streams inorder to further clarify the distribution and relative abundance of this dragonfly. Adults, nymphs and/or exuviae were found at 23 sites. Literature and museum searches bring to 72 locations in Missouri and 10 in Arkansas where this species has been found. Small to moderate-sized populations, restricted to the Interior Highlands, are known from at least 82 locations. Therefore, it is recommended that its global and Missouri rankings be changed from G2 and S2 to G3 and S3, respectively. Distribution and abundance of this species needs further study in Arkansas

    Staying On Track: Testing Higher Achievement's Long-Term Impact on Academic Outcomes and High School Choice

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    Higher Achievement is an intensive summer and after-school program that began in its current form in 1999 in Washington, DC. Today there are Higher Achievement programs in Washington, DC/Alexandria, VA; Richmond, VA; Pittsburgh, PA; and Baltimore, MD. The study includes the five Higher Education Achievement Centers that were operating in DC and Alexandria when the study began. Each center serves about 85 students, or "scholars", recruited mainly through school referral. Starting the summer before youth enter fifth or sixth grade and extending through eighth grade. Higher Achievement provides scholars with up to 650 hours of academic instructio0n per year, as well as enrichment activities and targeted, academic mentoring

    Designs of magnetic atom-trap lattices for quantum simulation experiments

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    We have designed and realized magnetic trapping geometries for ultracold atoms based on permanent magnetic films. Magnetic chip based experiments give a high level of control over trap barriers and geometric boundaries in a compact experimental setup. These structures can be used to study quantum spin physics in a wide range of energies and length scales. By introducing defects into a triangular lattice, kagome and hexagonal lattice structures can be created. Rectangular lattices and (quasi-)one-dimensional structures such as ladders and diamond chain trapping potentials have also been created. Quantum spin models can be studied in all these geometries with Rydberg atoms, which allow for controlled interactions over several micrometers. We also present some nonperiodic geometries where the length scales of the traps are varied over a wide range. These tapered structures offer another way to transport large numbers of atoms adiabatically into subwavelength traps and back.Comment: 9 pages, 10 figure
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