1,576 research outputs found

    UNINTENDED CONSEQUENCES OF MASS IMPRISONMENT: EFFECTS OF PATERNAL INCARCERATION ON CHILD SCHOOL READINESS

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    Though sociologists have examined the consequences of mass imprisonment of African-American men on the incarcerated men, their families, and their communities, no study has considered its impact on racial disparities in educational achievement. Analyzing the Fragile Families and Child Wellbeing Study and its rich paternal incarceration data, this study asks whether children with fathers who have been in prison are less prepared for school both academically and behaviorally as a result, and whether racial disparities in imprisonment explain some of the gap in white and black children‘s educational outcomes. Using a variety of estimation strategies, I show that experiencing paternal incarceration by age 5 is associated with lower child school readiness in behavioral but not cognitive skills. While the main effect of incarceration does not vary by race, boys with incarcerated fathers in their early childhood years have substantially worse behavioral skills at school entry. Because of the negative effects of incarceration on boys‘ behavioral skills and the much higher exposure of black children to incarceration, mass incarceration facilitates the intergenerational transmission of male behavioral disadvantage, and plays a role in explaining the persistently low achievement of black boys.imprisionment, families, boys, education, race, educational achievement

    Effects of real-time thermal aging on graphite/polyimide composites

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    As part of a program to evaluate high-temperature advanced composites for use on supersonic cruise transport aircraft, two graphite/polyimide composites have been aged at elevated temperatures for times up to 5.7 years. Work on the first, HT-S/710 graphite/polyimide, was started in 1974. Evaluation of the second polyimide, Celion 6000/LARC-160, began in 1980. Baseline properties are presented, including unnotched and notched tensile data as a function of temperature, compression, flexure, shear, and constant-amplitude fatigue data at R = 0.1 and R = -1. Tensile specimens were aged in ovens where pressure and aging temperatures were controlled for various times up to and including 50,000 hours. Changes in tensile strength were determined and plotted as a function of aging time. The HT-S/710 composite aged at 450 F and 550 F if compared to the Celion 6000/LARC-160 composite aged at 350 F and 450 F. After tensile testing, many of the thermal aging specimens were examined using a scanning electron microscope. Results of these studies are presented, and changes in properties and degradation mechanisms during high-temperature aging are discussed and illustrated using metallographic techniques

    Genetic Studies of Induced Mutants in \u3ci\u3eMelilotus alba\u3c/i\u3e III. Folded Leaflet, Elongatyed Stem, and Short-Petiole Dwarf

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    Observations of the F1, F2, and F3 progenies of crosses between normal annual Melilotus alba Desr. and three mutants, folded leaflet, elongated stem, and short-petiole dwarf, indicate that each of the mutant characters is controlled by a single recessive gene. Proposed symbols for the three mutant genes are f, el, and dsp, respectively. In limited tests for linkage, el appeared to be linked (12% recombination) to a gene for multifoliolate leaves (Mf). No linkage was detected between f and Mf, cu (low o-hydroxycinnamic acid), or b (low β-glucosidase activity)

    Time-temperature-stress capabilities of composite materials for advanced supersonic technology application, phase 1

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    Implementation of metal and resin matrix composites into supersonic vehicle usage is contingent upon accelerating the demonstration of service capacity and design technology. Because of the added material complexity and lack of extensive service data, laboratory replication of the flight service will provide the most rapid method of documenting the airworthiness of advanced composite systems. A program in progress to determine the time temperature stress capabilities of several high temperature composite materials includes thermal aging, environmental aging, fatigue, creep, fracture, and tensile tests as well as real time flight simulation exposure. The program has two parts. The first includes all the material property determinations and aging and simulation exposures up through 10,000 hours. The second continues these tests up to 50,000 cumulative hours. Results are presented of the 10,000 hour phase, which has now been completed

    Special Lagrangian cones with higher genus links

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    For every odd natural number g=2d+1 we prove the existence of a countably infinite family of special Lagrangian cones in C^3 over a closed Riemann surface of genus g, using a geometric PDE gluing method.Comment: 48 page

    Evaluation of a Full-Fat Soybean Ration for Channel Catfish Production in Cages

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    An experimental ration consisting of 50% full-fat soybeans, heated 170°C, was compared to a commercial trout chow in a 120-day feeding trial using two stocks of channel catfish, Ictalurus punctatus Rafinesque. Catfish were reared in 0.9 m³ floating cages, with 200 fish per cage, anchored in a 1.5 hectare farm pond. A Central Arkansas stock significantly outperformed a Southeast Arkansas stock for comparisons of net production and food conversion efficiency (FCE), with 92% greater production and 41% better FCE, respectively. Survival was 90% or greater for all fish. There was no significant difference in dress-out weight between the stocks. However, the catfish fed the trout ration had significantly lower amounts of body fat. The commercial trout chow overall was significantly better for fish production than the full-fat soybean ration. Production with trout chow was 84% greater than with the full-fat soybean ration. Food conversion efficiency was nearly 41% better with the trout ration, while percent body fat was 11% less. There were no differences in percent survival and percent dress-out weight between the rations. The Central Arkansas stock fed the commercial trout ration had the lowest production cost of 0.47¢ per 0.45 kg live weight, while the Southeastern stock had a higher production cost with either feed

    Variability for Traits Used to Estimate Silage Quality in Forage Sorghum Hybrids

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    The variation among 49 F1 forage sorghum [Sorghum bicolor (L.) Moench.] hybrids from a 7 X 7 cross-classified design was explored in 1979 and 1980 for the following silage traits: dry matter (DM), crude protein, in vitro dry matter disappearance (IVDMD), neutral detergent fiber, acid detergent fiber, acid detergent lignin, ammonia, lactate, and Brix of the juice from fresh stalks. Wider ranges generally were found for male than for female parental means. Means for most traits were significantly different among entries. Significant differences among hybrid means over males and over females were found for only DM, IVDMD, and Brix. Interactions with years existed for most traits. Genetic ratios calculated from the mean squares indicated that general combining ability was important for DM, IVDMD, and Brix. Simple correlation coefficients between traits measured on silage and on fresh-dried samples from the same hybrids were all significant. In view of the effort required to make and evaluate silage samples, initial selection for traits used to estimate quality in fresh-dried samples appears to be the best approach for improving the quality of forage sorghum silage

    Variability for Traits Used to Estimate Silage Quality in Forage Sorghum Hybrids

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    The variation among 49 F1 forage sorghum [Sorghum bicolor (L.) Moench.] hybrids from a 7 X 7 cross-classified design was explored in 1979 and 1980 for the following silage traits: dry matter (DM), crude protein, in vitro dry matter disappearance (IVDMD), neutral detergent fiber, acid detergent fiber, acid detergent lignin, ammonia, lactate, and Brix of the juice from fresh stalks. Wider ranges generally were found for male than for female parental means. Means for most traits were significantly different among entries. Significant differences among hybrid means over males and over females were found for only DM, IVDMD, and Brix. Interactions with years existed for most traits. Genetic ratios calculated from the mean squares indicated that general combining ability was important for DM, IVDMD, and Brix. Simple correlation coefficients between traits measured on silage and on fresh-dried samples from the same hybrids were all significant. In view of the effort required to make and evaluate silage samples, initial selection for traits used to estimate quality in fresh-dried samples appears to be the best approach for improving the quality of forage sorghum silage

    Puzzling It Out: The Current State of Scientific Knowledge on Pre-Kindergarten Effects - A Consensus Statement

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    Scientific research has established that if all children are to achieve their developmental potential, it is important to lay the foundation during the earliest years for lifelong health, learning, and positive behavior. A central question is how well our public pre-kindergarten (pre-K) programs are doing to build this foundation.Forty-two states and the District of Columbia, through 57 pre-K programs, have introduced substantial innovations in their early education systems by developing the infrastructure, program sites, and workforce required to accommodate pre-K education. These programs now serve nearly 30 percent of the nation's 4-year-olds and 5 percent of 3-year-olds
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