1,658 research outputs found

    Atrazine and Alachlor Adsorption Characteristics to Benchmark Soil Series in Eastern South Dakota

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    Corn, grain sorghum, and soybean are grown on about six million acres in eastern South Dakota each year. Two herbicides used routinely for weed control are atrazine(6-chloro-N-ethyl-N’-(1-methylethyl)-1,3,5-triazine-2,4-diamine) in corn and grain sorghum and alachlor (2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)acetamide) in all three crops. Six benchmark soil series that include a majority of the cropped acres treated with these herbicides are the Egan, Moody, Nora, and Brandt silty clay loams, and Clarno and Enet loams. Batch adsorption studies determined atrazine and alachlor binding characteristics to these soils and aids in assessing the amount of herbicide available for movement. These data also provide a basis for future use and management decisions for these and other related herbicides in similar soils. Soils from three horizons (A, B, and C) for each soil type were treated with atrazine or alachlor at four herbicide concentrations. Atrazine and alachlor sorption partition coefficients differed most in A horizon soils and ranged from 2.16 to 5.35 µmol1-1/n L1/nKg-1 for atrazine and 1.95 to 5.78 µmol1-1/n L1/nKg-1 for alachlor. Atrazine binding to A horizon soils ranked as Brandt \u3eEgan = Moody \u3e Enet = Clarno \u3e Nora. Alachlor binding to A horizon soils ranked as Brandt \u3eMoody \u3e Nora \u3e Enet \u3e Clarno. B and C horizon soils had lower binding for both herbicides; the sorption partition coefficient for atrazine ranged from 0.12 to 1.9 µmol1-1/n L1/nKg-1 while alachlor ranged from 0.43 to 1.64 µmol1-1/n L1/nKg-1. These data indicate that some soil types would be more susceptible to herbicide leaching than others. Once the herbicide moves through the A horizon, it may move rapidly through the lower soil profile (because of the decrease in binding capacity), and therefore, increase the vulnerability of the aquifer to contamination. Best management practices for these herbicides are being investigated to limit their movement through soil

    Metropolitan Fragmentation and Health Disparities: Is There a Link?

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    Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90559/1/j.1468-0009.2011.00659.x.pd

    Addendum: Lallana, M.J. et al. Use of Non-Steroidal Anti-Inflammatory Drugs and Associated Gastroprotection in a Cohort of Workers. 2018, 15, 1836

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    The authors wish to make the following correction to this paper [1]: Change in Funding In the original version of our article (Lallana, M.J. et al. Use of Non-Steroidal Anti-Inflammatory Drugs and Associated Gastroprotection in a Cohort of Workers. 2018, 15, 1836), insufficient source of funding was given. The authors wish to change the information in the Funding section from: Funding: This study was funded by the Instituto Carlos III, grant number (PI17/01704). to the correct version as follows: Funding: This study was funded by Proyecto del Fondo de InvestigaciĂłn Sanitaria, Instituto de Salud Carlos III (Ministerio de Ciencia e InnovaciĂłn) and Fondo Europeo de Desarrollo Regional (FEDER)(PI17/011704). The authors would like to apologize for any inconvenience caused to the readers by these changes

    Employment Expectations and Gross Flows by Type of Work Contract

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    There is growing interest in understanding firms’ temporary and permanent employment practices and how institutional changes shape them. Using data on Spanish establishments, we examine: (a) how employers adjust temporary and permanent job and worker flows to prior employment expectations, and (b) how the 1994 and 1997 labour reforms promoting permanent employment affected establishments’ employment practices. Generally, establishments’ prior employment expectations are realized through changes in all job and worker flows. However, establishments uniquely rely on temporary hires as a buffer to confront diminishing long-run employment expectations. None of the reforms significantly affected establishments’ net temporary or permanent employment flows.http://deepblue.lib.umich.edu/bitstream/2027.42/40032/3/wp646.pd

    Factors affecting woodland rodent growth

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    Very little information exists on the growth rates of woodland rodents and the drivers of body size dynamics that are observed in British populations. In this study, we use mark&-recapture data collected on two species living in sympatry, wood mice (Apodemus sylvaticus) and bank voles (Myodes glareolus). A third species of rodent, the yellow?necked mouse (Apodemus flavicollis) was also caught occasionally. We found the density of this third species negatively impacted the growth rate of both wood mice and bank voles. No impact of conspecific population density on growth for either species was found. Previous studies have suggested high conspecific population density can impact growth for some individuals of the population, but our populations may have not reached the densities required to elucidate these effects during the study

    Management of Occupational Manganism: Consensus of an Experts' Panel

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    Studies and Research Projects / Report R-417, Montréal, IRSST http://www.irsst.qc.ca/en/_publicationirsst_100134.html (Lucchini R was a member of the Expert Panel

    Impact of primary and secondary machinery tracks on fine root growth of sugar maple after selection cutting

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    Selection cutting, where approximately 30% of the trees are removed every 30 years, is the main silvicultural treatment used in temperate deciduous forests of Quebec (Canada). Concerns have been raised that the use of heavy machinery is creating soil disturbances that are negatively affecting the growth and survival of remaining trees. The aim of the study was to determine if heavy machinery is affecting the growth, morphology, and architecture of sugar maple (Acer saccharum Marsh.) fine roots in and around machinery tracks left after selection logging. The study site, a sugar maple dominated stand, was located in southern Quebec. Root ingrowth bags and standard root cores were used to compare fine root growth, morphology, and architecture in and around machinery tracks one year after logging. Fine root growth of maple was reduced fivefold in both primary (multiple trip) and secondary (only one trip) machinery tracks compared with the control. There was a nonstatistical reduction in fine root growth within 1 m of the tracks. Because machinery tracks cover between 15% and 25% of a stand after selection logging, such reduction in fine root growth could be significant for the growth and survival of the remaining mature maple trees

    Sperm design and variation in the New World blackbirds (Icteridae)

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    Post-copulatory sexual selection (PCSS) is thought to be one of the evolutionary forces responsible for the rapid and divergent evolution of sperm design. However, whereas in some taxa particular sperm traits are positively associated with PCSS, in other taxa, these relationships are negative, and the causes of these different patterns across taxa are poorly understood. In a comparative study using New World blackbirds (Icteridae), we tested whether sperm design was influenced by the level of PCSS and found significant positive associations with the level of PCSS for all sperm components but head length. Additionally, whereas the absolute length of sperm components increased, their variation declined with the intensity of PCSS, indicating stabilizing selection around an optimal sperm design. Given the diversity of, and strong selection on, sperm design, it seems likely that sperm phenotype may influence sperm velocity within species. However, in contrast to other recent studies of passerine birds, but consistent with several other studies, we found no significant link between sperm design and velocity, using four different species that vary both in sperm design and PCSS. Potential reasons for this discrepancy between studies are discussed

    A Multi-objective Exploratory Procedure for Regression Model Selection

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    Variable selection is recognized as one of the most critical steps in statistical modeling. The problems encountered in engineering and social sciences are commonly characterized by over-abundance of explanatory variables, non-linearities and unknown interdependencies between the regressors. An added difficulty is that the analysts may have little or no prior knowledge on the relative importance of the variables. To provide a robust method for model selection, this paper introduces the Multi-objective Genetic Algorithm for Variable Selection (MOGA-VS) that provides the user with an optimal set of regression models for a given data-set. The algorithm considers the regression problem as a two objective task, and explores the Pareto-optimal (best subset) models by preferring those models over the other which have less number of regression coefficients and better goodness of fit. The model exploration can be performed based on in-sample or generalization error minimization. The model selection is proposed to be performed in two steps. First, we generate the frontier of Pareto-optimal regression models by eliminating the dominated models without any user intervention. Second, a decision making process is executed which allows the user to choose the most preferred model using visualisations and simple metrics. The method has been evaluated on a recently published real dataset on Communities and Crime within United States.Comment: in Journal of Computational and Graphical Statistics, Vol. 24, Iss. 1, 201

    Culturo-Scientific Storytelling

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    In this article, we reflect on the functions of outreach in developing the modern scientific mind, and discuss its essential importance in the modern society of rapid technological development. We embed our approach to outreach in culturo-scientific thinking. This is constituted by embracing disciplinary thinking (in particular creativity) whilst appreciating the epistemology of science as an evolving dialogue of ideas, with numerous alternative perspectives and uncertain futures to be managed. Structuring scientific knowledge as an assemblage of interacting and evolving discipline-cultures, we conceive of a culturo-scientific storytelling to bring about positive transformations for the public in these thinking skills and ground our approach in quantum science and technologies (QST). This field has the potential to generate significant changes for the life of every citizen, and so a skills-oriented approach to its education, both formal and non-formal, is essential. Finally, we present examples of such storytelling in the case of QST, the classification and evaluation of which correspond to future work in which this narrative approach is studied in action
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