4,626 research outputs found

    THE KYOTO PROTOCOL: ECONOMIC EFFECTS OF ENERGY PRICES ON NORTHERN PLAINS DRYLAND GRAIN PRODUCTION

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    This study examined possible economic impacts on Northern Plains grain producers of policies that could be undertaken by the United States to comply with the Kyoto Protocol. The paper begins with a discussion of the potential effects of the Kyoto Protocol on prices of energy and inputs used in agricultural production. The next section describes the data and econometric models that were used to develop a field-scale, stochastic simulation model of the crop production system typical of the Northern Plains. This model is based on econometric production models estimated with a spatially referenced, statistically representative sample of farmers in Montana. The simulation analysis shows that the impacts of higher energy prices would tend to discourage the use of fallow, raise variable costs of production by 3 to 13%, and reduce net returns above variable cost by 6 to 18% in the case of spring wheat grown on fallow, Under the higher cost scenarios assumed in an analysis conducted by the Farm Bureau, production costs for spring wheat on fallow would increase by 15 to 27% and net returns would decline by 15 to 24%.Resource /Energy Economics and Policy,

    Interclutch variability in egg characteristics in two species of rail: Is maternal identity encoded in eggshell patterns?

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    © 2022 Johnson, McRae. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Maternal signatures are present in the eggs of some birds, but quantifying interclutch variability within populations remains challenging. Maternal assignment of eggs with distinctive appearances could be used to non-invasively identify renesting females, including hens returning among years, as well as to identify cases of conspecific brood parasitism. We explored whether King Rail (Rallus elegans) eggs with shared maternity could be matched based on eggshell pattern. We used NaturePatternMatch (NPM) software to match egg images taken in the field in conjunction with spatial and temporal data on nests. Since we had only a small number of marked breeders, we analyzed similar clutch images from a study of Eurasian Common Moorhens (Gallinula chloropus chloropus) with color-banded breeders for which parentage at many nests had been verified genetically to validate the method. We ran 66 King Rail clutches (n = 338 eggs) and 58 Common Moorhen clutches (n = 364 eggs) through NPM. We performed non-metric multidimensional scaling and permutational analysis of variance using the best egg match output from NPM. We also explored whether eggs could be grouped by clutch using a combination of egg dimensions and pattern data derived from NPM using linear discriminant analyses. We then scrutinized specific matches returned by NPM for King Rail eggs to determine whether multiple matches between the same clutches might reveal maternity among nests and inform our understanding of female laying behavior. To do this, we ran separate NPM analyses for clutches photographed over several years from two spatially distant parts of the site. With these narrower datasets, we were able to identify four instances where hens likely returned to breed among years, four likely cases of conspecific brood parasitism, and a within-season re-nesting attempt. Thus, the matching output was helpful in identifying congruent egg patterns among clutches when used in conjunction with spatial and temporal data, revealing previously unrecognized site fidelity, within-season movements, and reproductive interference by breeding females. Egg pattern data in combination with nest mapping can be used to inform our understanding of female reproductive effort, success, and longevity in King Rails. These methods may also be applied to other secretive birds and species of conservation concern.ECU ALS PLOS Institutional Account Progra

    771-3 Direct Characterization of F1ecalnide Binding Rates from Use-Dependent Conduction Delay In Canine Purkinje Fibers

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    To quantitatively characterize flecainide-induced channel blockade from usedependent conduction delay (CD), 12 canine purkinje fibers were studied using a dual microelectrode technique. During 60 sec of pacing at interstimulus intervals (ISI) of 1.25–0.4 sec with 2μM flecainide (FLEC), incremental CD followed a monoexponential time course, the rates of which were linearly related to the interpulse recovery interval (tr=ISI — action potential duration). Steady state block was an exponential function of the recovery rates. Use-dependent block derived from incremental CD and decremental squared conduction velocity (θ2) was characterized by the forward (k) and reverse (I) rate constants for the activated (a) and resting (r) states:ka (× 106) (mol-1 s-1)la (s-1)kr (× 102) (mol-1 s-1)Ir (s-1)CD7.0±2.612.0±4.40.6±1.74.01±1.63θ210.0±3.414.7±2.52.8±5.73.66±1.40Vmax(prox)6.8±2.315.9±5.05.1±10.34.22±1.11These rates reflect marked open state Na+ channel block and closed channel trapping at resting membrane potentials with FLEC. The addition of 1μM isoproterenol (ISO) to FLEC-superfused fibers reversed the FLEC-induced reduction of θ2 from 1.79±0.7 to 1.89±0.89 (m/s)2 (p=0.017) without changing V˙max. The rate constants for FLEC binding and unbinding were not altered by ISO. Thus FLEC's apparent binding rates can be quantified from its use-{jependent effects on conduction. Both ISO's selective reversal of FLEC effect on θ2 but not V˙max and the absence of changes in the rate constants suggest that the modulation of FLEC effect is due to an alteration in passive membrane properties. These characterizations will facilitate subsequent comparisons of FLEC interactions in pathologic and hyperadrenergic states in vivo

    Working With Faith-Based Communities to Develop an Education Tool kit on Relationships, Sexuality, and Contraception

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    Communities disproportionately affected from higher rates of unplanned teen births are in need of sustainable approaches to prevention strategies. One approach is to build the capacity of faith-based communities (FBCs) to address the sexual health needs of the surrounding community. However there is a need for comprehensive, user-friendly resources designed for FBCs that provide critical decision-making information related to pregnancy prevention inclusive of contraception. Using community-based, theoretical and practice-informed strategies, we developed a user-friendly sexuality education tool kit in five phases: (1) building relationships with faith leaders; (2) piloting educational sessions within churches; (3) gaining insight from participating faith leaders; (4) creating the tool kit; and (5) collecting feedback from training and implementation. Our findings suggest faith leaders remained motivated to overcome perceived barriers by their mission to serve their communities. A sexuality education tool kit that is respectful and guided by the input of FBCs can be a viable and innovative approach to address teen pregnancy

    Efficient Algorithm for Nonpoint Source Pollution Control Problems

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    A dynamic programming algorithm is proposed for a class of nonpoint source pollution control problems. The inherently combinatorial nature of these problems--stemming from the discrete nature of the decision variables, which are production and conservation practices--gives them a special knapsack structure with multiple right hand sides and additional multiple choice constraints. This paper focuses on the computer implementation of this algorithm and its numerical testing and behavior compared with standard integer programming codes. The results show the robustness and relative efficiency of the approach. Furthermore, this paper demonstrates that dynamic programming can be used to generate sensitivity analysis information for multiple choice knapsack problems

    Student expectations and dyadic interactions with physical education teachers of third-grade children

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    The purpose of this study was to investigate the differences among student expectations, student sex, and teachers with respect to teacher-student dyadic interactions of third-grade children. Student expectations of 140 third-grade children enrolled in two different schools in Guilford County, North Carolina, were measured by the Johnson Motor Performance Expectancy Scale for Children (JMPES). A pretest and posttest of the JMPES were administered during the first and last weeks of a nine-week instructional period. The upper and lower thirds of the JMPES scores were used to identify high and low expectancy groups. Teacher-student dyadic interactions of two female physical education teachers, each at a different school, and individual third-grade students in their classes were measured by the Dyadic Adaptation of CAFIAS (DAC). Teacher-student dyadic interactions were observed and recorded by two trained coders on 18 randomly selected occasions during the nine-week period

    Attitudinal Outcomes of a Multicultural Learning Community Experience: A Qualitative Analysis

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    Research investigating the long-term effects of learning communities on students is scarce. This qualitative study focuses on the results of 24 in-depth interviews with students three years after participating in a first year learning community at a private, selective Midwestern university. Interview questions were designed to probe students’ shifts in personal biases and stereotypes, factors related to their decisions to become involved with the learning community, self-reported levels of satisfaction with the learning community, and suggestions for improving future learning communities. Results of the interviews were positive, and also suggested the value of explicit communication about the purpose of the learning community. The authors point out the value of ongoing continuous improvement efforts

    Relative Fitness of Fluoroquinolone-resistant Streptococcus pneumoniae

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    Fluoroquinolone resistance in Streptococcus pneumoniae is primarily mediated by point mutations in the quinolone resistance–determining regions of gyrA and parC. Antimicrobial resistance mutations in housekeeping genes often decrease fitness of microorganisms. To investigate the fitness of quinolone-resistant S. pneumoniae (QRSP), the relative growth efficiencies of 2 isogenic QRSP double mutants were compared with that of their fluoroquinolone-susceptible parent, EF3030, by using murine nasopharyngeal colonization and pneumonia models. Strains containing the GyrA: Ser81Phe, ParC: Ser79Phe double mutations, which are frequently seen in clinical QRSP, competed poorly with EF3030 in competitive colonization or competitive lung infections. However, they efficiently produced lung infection even in the absence of EF3030. The strain containing the GyrA: Ser81Phe, ParC: Ser79Tyr double mutations, which is seen more frequently in laboratory-derived QRSP than in clinical QRSP, demonstrated reduced nasal colonization in competitive or noncompetitive lung infections. However, the strain was equally able to cause competitive or noncompetitive lung infections as well as EF3030
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