546 research outputs found

    Constraints on Martian Differentiation Processes from Rb-Sr and Sm-Nd Isotopic Analyses of the Basaltic Shergottite QUE 94201

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    Isotopic analyses of mineral, leachate, and whole rock fractions from the Martian shergottite meteorite QUE 94201 yield Rb-Sr and Sm-Nd crystallization ages of 327 +/- 12 and 327 +/- 19 Ma, respectively. These ages are concordant, although the isochrons are defined by different fractions within the meteorite. Comparison of isotope dilution Sm and Nd data for the various QUE 94201 fractions with in situ ion microprobe data for QUE 94201 minerals from the literature demonstrate the presence of a leachable crustal component in the meteorite. This component is likely to have been added to QUE 94201 by secondary alteration processes on Mars, and can affect the isochrons by selectively altering the isotopic systematics of the leachates and some of the mineral fractions. The absence of crustal recycling processes on Mars may preserve the geochemical evidence for early differentiation and the decoupling of the Rb-Sr and Sm-Nd isotopic systems, underscoring one of the fundamental differences between geologic processes on Mars and the Earth

    Pastoral and anti-pastoral patterns in John Updike's fiction /

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    Effects of Ethnicity and Type of Crime on Juvenile Offenders’ Recidivism Risk

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    Juvenile crime in the United States has been a persistent social problem that has reached epidemic proportions. The purpose of this between-subjects, comparative quantitative study was to examine the relationship between recidivism risk and the type of crime, ethnicity, and race of the juvenile. Social learning theory was used to guide the study. Archival data of 59,653 cases were collected from Inter-University Consortium Political and Social Research. Correctional Offender Management Profiling for Alternative Sanctions was used to assess the dependent variable recidivism risk. The independent variables were ethnicity and type of crime of the offender reported in the Transcript of the Record Conviction Report. The variables were tested using the Kruskal-Wallis test. For each of the 3 research questions by type of crime, by ethnic group, and interaction of both, the null hypothesis was rejected. Findings indicated that White, African American, and Hispanic juveniles by type of crime were viewed and treated differently in the juvenile justice system. The social change implication of the findings come from considering the impact of recidivism risk for youth of color and type of crime by juvenile justice agencies recognizing these effects on the services in the community

    The Texture of Surficial Sediments in Western Long Island Sound off the Norwalk Islands, Connecticut

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    Grain-size analyses were performed on 69 samples from western Long Island Sound. The relative grain-size frequency distributions and related statistics are reported herein. Descriptions of the benthic character from video tapes and still camera photographs of the bottom at these stations, and 33 others, are also presented. The southern and eastern parts of the study area are dominated by poorly sorted clayey silts that have nearly symmetrical distributions. Gravelly sediments are prevalent in the shallow northwestern part of the study area, but are also present in central part of the study area. Bands of sand, silty sand, and sand-silt-clay occur on the flanks of the gravelly areas

    Ancient maize from Chacoan great houses: Where was it grown?

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    In this article, we compare chemical (87Sr/86Sr and elemental) analyses of archaeological maize from dated contexts within Pueblo Bonito, Chaco Canyon, New Mexico, to potential agricultural sites on the periphery of the San Juan Basin. The oldest maize analyzed from Pueblo Bonito probably was grown in an area located 80 km to the west at the base of the Chuska Mountains. The youngest maize came from the San Juan or Animas river floodplains 90 km to the north. This article demonstrates that maize, a dietary staple of southwestern Native Americans, was transported over considerable distances in pre-Columbian times, a finding fundamental to understanding the organization of pre-Columbian southwestern societies. In addition, this article provides support for the hypothesis that major construction events in Chaco Canyon were made possible because maize was brought in to support extra-local labor forces

    Organic Carbon, Hydrogen, and Nitrogen Concentrations in Surficial Sediments from Western Long Island Sound, Connecticut and New York

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    Total organic carbon, hydrogen, and nitrogen (CHN) analyses were performed on 147 surficial sediment samples from study areas off the Norwalk Islands and Milford, Connecticut, in western Long Island Sound. The CHN data and gross lithologic descriptions of the sediments are reported herein. The concentrations of total organic carbon (TOC), hydrogen, and nitrogen in these samples average 1.54, 1.40, and 0.17 weight percent, respectively. The individual CHN concentrations vary inversely with grain size, with CHN values increasing with the percent fines. Increasing nutrient inputs and decreasing circulation cause TOC and nitrogen values to generally increase westward within the Sound. C/N molar elemental ratios suggest that, except for the shoreward northwestern corner of the Norwalk Islands survey site, marine phytoplankton are probably the primary source of sedimentary organic matter in the study areas. Concentrations of the sedimentary organic matter are significantly higher in the spring than in the late summer, suggesting that these concentrations vary seasonally

    The accuracies of DNA-based estimates of genetic merit derived from Angus or multibreed beef cattle training populations

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    Several organizations have developed prediction models for molecular breeding values (MBV) for quantitative growth and carcass traits in beef cattle using Bovine SNP50 genotypes and phenotypic or EBV data. Molecular breeding values for Angus cattle have been developed by IGENITY, Pfi zer Animal Genetics, and a collaboration between researchers from Iowa State University and the University of Missouri-Columbia (ISU/UMC). The U.S. Meat Animal Research Center (USMARC; Clay Center, NE) has also developed MBV for 16 cattle breeds using 2 multibreed populations, the Germplasm Evaluation (GPE) Program and the 2,000 Bull Project (2KALL), and 2 single breed subpopulations of the 2,000 Bull Project, Angus (2KAN) and Hereford (2KHH). In this study, these MBV were assessed relative to commercial ranch EBV estimated from the progeny phenotypes of Angus bulls naturally mated in multisire breeding pastures to commercial cows: 121 for USMARC MBV, 99 for ISU/UMC MBV, and 29 for IGENITY and Pfizer MBV (selected based on number of progeny carcass records). Five traits were analyzed: weaning weight (WW), HCW, marbling score (MS), rib-eye muscle area (RE), and, for IGENITY and Pfi zer only, feedlot ADG. The average accuracies of MBV across traits were 0.38 ± 0.05 for IGENITY, 0.61 ± 0.12 for Pfizer, 0.46 ± 0.12 for ISU/UMC, 0.16 ± 0.04 for GPE, 0.26 ± 0.05 for 2KALL, 0.24 ± 0.04 for 2KAN, and 0.02 ± 0.12 for 2KHH. Angus-based MBV (IGENITY, Pfizer, ISU/UMC, and 2KAN) explained larger proportions of genetic variance in this population than GPE, 2KALL, or 2KHH MBV for the same traits. In this data set, IGENITY, Pfizer, and ISU/UMC MBV were predictive of realized performance of progeny, and incorporation of that information into national genetic evaluations would be expected to improve EPD accuracy, particularly for young animals

    New insights into the relationship between mass eruption rate and volcanic column height based on the IVESPA data set

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    Rapid and simple estimation of the mass eruption rate (MER) from column height is essential for real-time volcanic hazard management and reconstruction of past explosive eruptions. Using 134 eruptive events from the new Independent Volcanic Eruption Source Parameter Archive (IVESPA, v1.0), we explore empirical MER-height relationships for four measures of column height: spreading level, sulfur dioxide height, and top height from direct observations and as reconstructed from deposits. These relationships show significant differences and highlight limitations of empirical models currently used in operational and research applications. The roles of atmospheric stratification, wind, and humidity remain challenging to detect across the wide range of eruptive conditions spanned in IVESPA, ultimately resulting in empirical relationships outperforming analytical models that account for atmospheric conditions. This finding highlights challenges in constraining the MER-height relation using heterogeneous observations and empirical models, which reinforces the need for improved eruption source parameter data sets and physics-based models

    Metallized Nanotube Polymer Composite (MNPC)

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    This viewgraph presentation describes the Metallized Nanotube Polymer Composites (MNPC) used in aerospace vehicles
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