The effects of test-based retention on student outcomes over time: Regression discontinuity evidence from Florida

Many American states require that students lacking basic reading proficiency after third grade be retained and remediated. We exploit a discontinuity in retention probabilities under Florida's test-based promotion policy to study its effects on student outcomes through high school. We find large positive effects on achievement that fade out entirely when retained students are compared to their same-age peers, but remain substantial through grade 10 when compared to students in the same grade. Being retained in third grade due to missing the promotion standard increases students' grade point averages and leads them to take fewer remedial courses in high school but has no effect on their probability of graduating.We are grateful to the Florida Department of Education for providing the primary dataset for this study. We thank Stefan Bauernschuster, Matthew Chingos, Andrew Ho, Paul Peterson, Ludger Woessmann, and the seminar participants at the National Bureau of Economic Research, Harvard University, the Ifo Institute, Mathematica Policy Research, Stanford University, the European Economic Association Meeting in Gothenburg, the European Association of Labour Economists Meeting in Turin and the Swedish Institute for Social Research for helpful comments. The Helios Education Foundation provided financial support for this research. The views contained herein are not necessarily those of the Helios Education Foundation. Any errors are our own. (Helios Education Foundation)http://sites.bu.edu/marcuswinters/files/2017/09/NBER-Grade-Retention.pdfhttp://sites.bu.edu/marcuswinters/files/2017/09/NBER-Grade-Retention.pdfAccepted manuscrip

Paid and Unpaid Overtime Working in Germany and the UK

Significant numbers of employees work more hours in the workplace than their contract stipulates. Such overtime work can either be paid or unpaid. This research considers overtime working in Germany and the UK and shows that the quantitative significance of both paid and unpaid overtime is greater in the UK. Empirical work is based on the UK Labour Force Survey and the German Socio-Economic Panel in 1993. Overtime influences the effective average hourly wage positively in the case where overtime is paid at premium rates and negatively where such hours are not remunerated. We demonstrate via Mincer wage growth equations that accounting for unpaid work leads to revised estimates of experience and tenure both within and between the two countries. We estimate overtime hours equations, using these to test several of our theories that might explain the apparent irrationality of unpaid work

Dieta de la viuda negra, <i>Latrodectus mirabilis</i> (Theridiidae) en dos cultivos de cereales del centro de Argentina

The spider Latrodectus mirabilis (Holmberg, 1876) is commonly found in cereals crops of central Argentina. We studied its diet composition at the field and capture rate on leaf-cutting ants based on laboratory experiments. This study comprises the first approach that documents the diet of L. mirabilis in wheat and oat fields of central Argentina. We identified 1,004 prey items collected from its webs during the last phenological stages of both cereal crops. The prey composition was variable but the spiders prey mainly on ants (Formicidae, Hymenoptera), who represented more than 86% of the total. Meanwhile, in the capture rate experiences we registered a high proportion of ants captured by spiders at the beginning of experiences, capturing the half of the ants from total in the first four hours. Summarizing, we reported a polyphagous diet of this spider species in wheat and oat fields. Ants were the most important prey item of this spider, as found in other Latrodectus spiders around the world.La araña Latrodectus mirabilis (Holmberg, 1876) se encuentra comúnmente en cultivos de cereales del centro de Argentina. Se estudió la composición de la dieta a campo y la tasa de captura sobre hormigas cortadoras negras a laboratorio. Este estudio documenta el primer registro de la dieta de L. mirabilis en cultivos de trigo y avena del centro de Argentina. Se identificaron 1004 ítem presa colectados de las telas de L. mirabilis en las últimas etapas fenológicas de ambos cultivos. La composición de presas fue variable, pero las arañas se alimentaron principalmente de hormigas (Formicidae, Hymenoptera), las cuales representaban más del 86% del total de las presas capturadas. A su vez, en las experiencias de tasa de captura, registramos una alta tasa de captura de hormigas al inicio de las mismas, capturando la mitad de las hormigas en las primeras cuatro horas. En resumen, reportamos una dieta polífaga en esta especie de araña en los cultivos de trigo y avena. El ítem presa más importante fueron las hormigas, resultados similares a los encontrados en otras especies del género Latrodectus.Centro de Estudios Parasitológicos y de Vectore

Dieta de la viuda negra, <i>Latrodectus mirabilis</i> (Theridiidae) en dos cultivos de cereales del centro de Argentina

The spider Latrodectus mirabilis (Holmberg, 1876) is commonly found in cereals crops of central Argentina. We studied its diet composition at the field and capture rate on leaf-cutting ants based on laboratory experiments. This study comprises the first approach that documents the diet of L. mirabilis in wheat and oat fields of central Argentina. We identified 1,004 prey items collected from its webs during the last phenological stages of both cereal crops. The prey composition was variable but the spiders prey mainly on ants (Formicidae, Hymenoptera), who represented more than 86% of the total. Meanwhile, in the capture rate experiences we registered a high proportion of ants captured by spiders at the beginning of experiences, capturing the half of the ants from total in the first four hours. Summarizing, we reported a polyphagous diet of this spider species in wheat and oat fields. Ants were the most important prey item of this spider, as found in other Latrodectus spiders around the world.La araña Latrodectus mirabilis (Holmberg, 1876) se encuentra comúnmente en cultivos de cereales del centro de Argentina. Se estudió la composición de la dieta a campo y la tasa de captura sobre hormigas cortadoras negras a laboratorio. Este estudio documenta el primer registro de la dieta de L. mirabilis en cultivos de trigo y avena del centro de Argentina. Se identificaron 1004 ítem presa colectados de las telas de L. mirabilis en las últimas etapas fenológicas de ambos cultivos. La composición de presas fue variable, pero las arañas se alimentaron principalmente de hormigas (Formicidae, Hymenoptera), las cuales representaban más del 86% del total de las presas capturadas. A su vez, en las experiencias de tasa de captura, registramos una alta tasa de captura de hormigas al inicio de las mismas, capturando la mitad de las hormigas en las primeras cuatro horas. En resumen, reportamos una dieta polífaga en esta especie de araña en los cultivos de trigo y avena. El ítem presa más importante fueron las hormigas, resultados similares a los encontrados en otras especies del género Latrodectus.Centro de Estudios Parasitológicos y de Vectore

Digenean trematodes of Seriolella porosa (Pisces, Centrolophidae) in San Matías Gulf, Argentina

Seriolella porosa (Silver warehou) is an important fish resource in the Argentine Sea. No previous studies have been carried out to date on its parasite fauna. The present study aims to (i) identify the digenean trematodes that parasitize Silver warehou, (ii) estimate parasite frequency and abundance, and (iii) establish their relationship with fish size and sex. A total of 100 specimens of S. porosa from San Matías Gulf, Argentina were examined between September and October 2006. Host size and sex were determined. Parasites extracted from the stomach lumen were fixed, conserved in 5% formalin, and stained with Langeron's hydrochloric carmine. The following parameters were also determined: dispersion coefficient, prevalence, intensity, and parasite abundance. Differences in parasitism were assessed using non-parametric tests. Four adult digenean species were found in the stomach, namely Lecithocladium cristatum, Aponurus laguncula, Elytrophalloides oatesi and Gonocerca cf. phycidis. L. cristatum was not only dominant but also the most prevalent and abundant species. None of the digeneans showed interspecific association with each other and therefore they might follow different patterns of colonization (i. e., different intermediate hosts, seasonal and/or spatial distribution of the infective stages). Significant differences were observed among the digeneans analyzed in respect to the sex of the host. Results from this study show that Silver warehou plays a key role as a final host of a significant number of digeneans in the ecosystem. This study is the first step in an attempt to further determine the larval stages in intermediate hosts in San Matías Gulf.Centro de Estudios Parasitológicos y de Vectore

Digenean trematodes of Seriolella porosa (Pisces, Centrolophidae) in San Matías Gulf, Argentina

Seriolella porosa (Silver warehou) is an important fish resource in the Argentine Sea. No previous studies have been carried out to date on its parasite fauna. The present study aims to (i) identify the digenean trematodes that parasitize Silver warehou, (ii) estimate parasite frequency and abundance, and (iii) establish their relationship with fish size and sex. A total of 100 specimens of S. porosa from San Matías Gulf, Argentina were examined between September and October 2006. Host size and sex were determined. Parasites extracted from the stomach lumen were fixed, conserved in 5% formalin, and stained with Langeron's hydrochloric carmine. The following parameters were also determined: dispersion coefficient, prevalence, intensity, and parasite abundance. Differences in parasitism were assessed using non-parametric tests. Four adult digenean species were found in the stomach, namely Lecithocladium cristatum, Aponurus laguncula, Elytrophalloides oatesi and Gonocerca cf. phycidis. L. cristatum was not only dominant but also the most prevalent and abundant species. None of the digeneans showed interspecific association with each other and therefore they might follow different patterns of colonization (i. e., different intermediate hosts, seasonal and/or spatial distribution of the infective stages). Significant differences were observed among the digeneans analyzed in respect to the sex of the host. Results from this study show that Silver warehou plays a key role as a final host of a significant number of digeneans in the ecosystem. This study is the first step in an attempt to further determine the larval stages in intermediate hosts in San Matías Gulf.Centro de Estudios Parasitológicos y de Vectore

The intergenerational transmission of cognitive skills: an investigation of the causal impact of families on student outcomes

The extensive literature on intergenerational mobility highlights the importance of family linkages but fails to provide credible evidence about the underlying family factors that drive the pervasive correlations. We employ a unique combination of Dutch survey and registry data that links math and language skills across generations. We identify a causal connection between cognitive skills of parents and their children by exploiting within-family between-subject variation in these skills. The data also permit novel IV estimation that isolates variation in parental cognitive skills due to school and peer quality. The between-subject and IV estimates of the key intergenerational persistence parameter are strikingly similar and close at about 0.1. Finally, we show the strong influence of family skill transmission on children’s choices of STEM fields

Wireless Performance of a Fully Passive Neurorecording Microsystem Embedded in Dispersive Human Head Phantom

This paper reports the wireless performance of a biocompatible fully passive microsystem implanted in phantom media simulating the dispersive dielectric properties of the human head, for potential application in recording cortical neuropotentials. Fully passive wireless operation is achieved by means of backscattering electromagnetic (EM) waves carrying 3rd order harmonic mixing products (2f(sub 0) plus or minus f(sub m)=4.4-4.9 GHZ) containing targeted neuropotential signals (fm approximately equal to 1-1000 Hz). The microsystem is enclosed in 4 micrometer thick parylene-C for biocompatibility and has a footprint of 4 millimeters x 12 millimeters x 500 micrometers. Preliminary testing of the microsystem implanted in the lossy biological simulating media results in signal-to-noise ratio's (SNR) near 22 (SNR approximately equal to 38 in free space) for millivolt level neuropotentials, demonstrating the potential for fully passive wireless microsystems in implantable medical applications

Barley Nodulin 26-like Intrinsic Protein permeates water, metalloids, saccharides, and ion pairs due to structural plasticity and diversification

OnlinePublAquaporins can facilitate the passive movement of water, small polar molecules and some ions. Here, we examined solute selectivity for the barley Nodulin 26-like Intrinsic Protein (HvNIP2;1) embedded in liposomes and examined through stopped-flow light scattering spectrophotometry and Xenopus laevis oocyte swelling assays. We found that HvNIP2;1 permeates water, boric and germanic acids, sucrose, and lactose but not d-glucose or d-fructose. Other saccharides, such as neutral (d-mannose, d-galactose, d-xylose, d-mannoheptaose) and charged (N-acetyl d-glucosamine, d-glucosamine, d-glucuronic acid) aldoses, disaccharides (cellobiose, gentiobiose, trehalose), trisaccharide raffinose, and urea, glycerol, and acyclic polyols were permeated to a much lower extent. We observed apparent permeation of hydrated KCl and MgSO4 ions, while CH3COONa and NaNO3 permeated at significantly lower rates. Our experiments with boric acid and sucrose revealed no apparent interaction between solutes when permeated together, and AgNO3 or H[AuCl4] blocked the permeation of all solutes. Docking of sucrose in HvNIP2;1 and spinach water-selective SoPIP2;1 aquaporins revealed the structural basis for sucrose permeation in HvNIP2;1 but not in SoPIP2;1, and defined key residues interacting with this permeant. In a biological context, sucrose transport could constitute a novel element of plant saccharide-transporting machinery. Phylogenomic analyses of 164 Viridiplantae and 2,993 Archaean, bacterial, fungal, and Metazoan aquaporins rationalized solute poly-selectivity in NIP3 sub-clade entries and suggested that they diversified from other sub-clades to acquire a unique specificity of saccharide transporters. Solute specificity definition in NIP aquaporins could inspire developing plants for food production.Akshayaa Venkataraghavan, Julian G. Schwerdt, Stephen D. Tyerman, Maria Hrmov