46 research outputs found

    Mineral paragenesis of the granulite facies in the Lake George area, New York

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    The Lake George Area belongs to the southeastern part of the Adirondack Highlands. The rocks of this area show variations in mineral assemblages which are caused by differences in bulk chemical composition. This makes it unsuccessful to use a subdivision of the granulite facies which is suggested by de Waard (1965). The CFM diagram (Abbott, 1982) is used to show the relationship between composition and paragenesis of the Lake George Area. In this study, a different result has been found in the order of partitioning of Fe between coexisting minerals, namely, garnet\u3ehornblende\u3ebiotite\u3eorthopyroxene\u3eclinopyroxene. The hornblende granitic gneiss belongs to a different subfacies from the mafic granulite and charnockitic gneiss according to Abbott\u27s subdivision of the facies. But, following the order of XFe of the minerals from this study, the typical mineral assemblage of this rock, hornblende-garnet-biotite, may belong to the same subfacies as the other rock types of this area. The study of biotites of metapelite in the Lake George Area indicates different substitution mechanisms in different regions of the granulite facies. From the garnet-orthopyroxene (clinopyroxene) thermometer, 710°C was obtained for the highest estimate of the metamorphism. This temperature condition appears to be consistent with the observed mineral assemblages of a lower-grade part of the granulite facies and confirms the isotherm pattern of Bohlen et al. (1985). Cooling ages of 971±17 Ma, 882±7 Ma and 656±17 Ma were obtained for hornblende, biotite and microcline, respectively, with 40Ar/39Ar dating method. With cooling ages of minerals and reasonable closure temperatures for each mineral, average cooling rates are calculated: 2.7°C/Ma for the time interval of peak metamorphism-hornblende, 2.2°C/Ma for hornblende-biotite, and 0.7°C/Ma for biotite-microcline

    Drought Indicator Assessment In Lake Management Using A Bayesian Network Model

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    To implement more integrated and effective drought management under the consideration of uncertainties, it is essential to identify and assess the underlying interactions and impacts of drought indicators to the economic and ecological systems in a lake. In this study, a Bayesian network model was developed to facilitate the assessment and response of drought indicators in the context of economic and environmental utilities

    Changes of Tree Species Composition and Distribution Patterns in Mts. Jiri and Baegun, Republic of Korea over 15 Years

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    Long-term changes in the abundance and distribution of tree species in the temperate forests of South Korea remain poorly understood. We investigated the changes in tree species composition in temperate mountainous forests using survey data from 130 permanent plots (0.1 ha) from the past 15 years (1998–2012) distributed across Mts. Jiri and Baegun, South Korea. The tree communities showed positive net changes in terms of stand density, richness, diversity, and evenness. At the species level, the change in relative species composition has been mainly driven by species such as Quercus mongolica, Carpinus laxiflora, Quercus serrata, Quercus variabilis, Styrax japonicus, Lindera erythrocarpa, and Pinus densiflora. These changes were categorized into five groups representing gradual increase or decrease, establishment, extinction, or fluctuation in species populations. At the community level, the changes in species composition showed consistent and directional increases in the annual rate of change for the mean species traits, including stand prevalence, pole growth rate, adult growth rate, and adult stature. Based on additive models, topographic variables (elevation, latitude, longitude, slope, topographic wetness index, and curvature) were more strongly associated with the distribution of species diversity than climate variables (annual mean minimum and maximum temperatures, temperature seasonality, annual rainfall, rainfall seasonality). Elevation was the most significant driver, followed by latitude and longitude. This study reveals the dynamics of change in tree species composition and distribution along topographical and climate gradients in South Korea and contributes to a broader understanding of temperate forest ecosystems for the purpose of better forest management

    Integrated Bayesian Network Models to Predict the Fate and Transport of Natural Estrogens at a Swine Farrowing CAFO

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    <p>Natural steroidal estrogen hormones in swine wastes generated from Concentrated Animal Feeding Operations (CAFOs) have become a potential pollutant to many aquatic environments due to their adverse impacts on the reproductive biology of aquatic organisms. In North Carolina, the swine CAFO industry is a major agricultural economic enterprise that is responsible for the generation of large volumes of waste. However, there is limited scientific understanding regarding the concentration, fate, and transport of the estrogenic compounds from these swine facilities into terrestrial and aquatic environments. To address this issue, my research involved the development and application of integrated Bayesian networks (BNs) models that can be used to better characterize and assess the generation, fate, and transport of site-specific swine CAFO-derived estrogen compounds. The developed model can be used as decision support tool towards estrogen risk assessment. Modularized and melded BN approaches were used to capture the predictive and casual relationships of the estrogen budget and its movement within and between the three major systems of a swine farrowing CAFO. These systems include the animal barns, the anaerobic waste lagoon, and the spray fields. For the animal barn system, a facility-wide estrogen budget was developed to assess the operation-specific estrogen excretion, using an object-oriented BN (OOBN) approach. The developed OOBN model provides a means to estimate and predict estrogen fluxes from the whole swine facility in the context of both estrogen type and animal operating unit. It also accounts for the uncertainties in the data and in our understanding of the system. Next, mass balance melding BN models were developed to predict the natural estrogen fates and budgets in two lagoon compartments, the slurry and the sludge storage. This involved utilizing mass balance equations to account for the mechanisms of flushing, sorption, transformation, settling, and burial reactions of estrogen compounds in the slurry and sludge storages. As an alternative approach, a regression based BN melding approach was developed to both characterize estrogen fate and budgets as a result of the sequential transformation processes between natural estrogen compounds and to assess the seasonal effects on the estrogen budgets in the two different lagoon compartments. Finally, a dynamic BN model was developed to characterize rainfall-driven estrogen runoff processes from the spray fields. The dynamic BN models were used to assess the potential risk of estrogen runoff to adjacent waterways. In addition, the dynamic model was used to quantify the effects of manure application rates, rainfall frequency, the time of rainfall and irrigation, crop types, on-farm best management practices, seasonal variability, and successive rainfall and manure application events on estrogen runoff. </p><p>The model results indicate that the farrowing barn is the biggest contributor of total estrogen as compared to the breeding and gestation operating barns. Once the estrogen reaches the anaerobic lagoon, settling and burial reactions were shown to be the most significant factors influencing estrogen levels in the slurry and sludge, respectively. The estrogen budgets in the lagoon were also found to vary by season, with higher slurry and sludge estrogen levels in the spring as compared to the summer. The risk of estrogen runoff was predicted to be lower in the summer as compared to the spring, primarily due to the spray field crop management plans adopted. The results also indicated that Bermuda grass performed more favorably when compared to soybean, when it came to retaining surface water runoff in the field. Model predictions indicated that there is a low risk of estrogen runoff losses from the spray fields under multiple irrigation and rainfall events, unless the time interval between irrigation was less than 10 days and/or in the event of a prolonged high magnitude rainstorm event. Overall, the estrone was the most persistent form of natural estrogens in the three major systems of the swine farrowing CAFO.</p>Dissertatio

    C.H.G. Necker : directeur général des finances : monument de la reconnaissance publique : [estampe] / J.V. del. ; Boknam sculp.

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    Référence bibliographique : De Vinck, 1405Référence bibliographique : Vidéodisque, 28315-28317Appartient à l’ensemble documentaire : Est18Rev

    Efficacy of Diphenyleneiodonium Chloride (DPIC) Against Diverse Plant Pathogens

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    Many of the fungicides and antibiotics currently available against plant pathogens are of limited use due to the emergence of resistant strains. In this study, we examined the effects of diphenyleneiodonium chloride (DPIC), an inhibitor of the superoxide producing enzyme NADPH oxidase, against fungal and bacterial plant pathogens. We found that DPIC inhibits fungal spore germination and bacterial cell proliferation. In addition, we demonstrated the potent antibacterial activity of DPIC using rice heads infected with the bacterial pathogen Burkholderia glumae which causes bacterial panicle blight (BPB). We found that treatment with DPIC reduced BPB when applied during the initial flowering stage of the rice heads. These results suggest that DPIC could serve as a new and useful antimicrobial agent in agriculture

    Biological Efficacy of Streptomyces sp. Strain BN1 against the Cereal Head Blight Pathogen Fusarium graminearum

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    Fusarium head blight (FHB) caused by the filamentous fungus Fusarium graminearum is one of the most severe diseases threatening the production of small grains. Infected grains are often contaminated with mycotoxins such as zearalenone and trichothecences. During survey of contamination by FHB in rice grains, we found a bacterial isolate, designated as BN1, antagonistic to F. graminearum. The strain BN1 had branching vegetative hyphae and spores, and its aerial hyphae often had long, straight filaments bearing spores. The 16S rRNA gene of BN1 had 100% sequence identity with those found in several Streptomyces species. Phylogenetic analysis of ITS regions showed that BN1 grouped with S. sampsonii with 77% bootstrap value, suggesting that BN1 was not a known Streptomyces species. In addition, the efficacy of the BN1 strain against F. graminearum strains was tested both in vitro and in vivo. Wheat seedling length was significantly decreased by F. graminearum infection. However, this effect was mitigated when wheat seeds were treated with BN1 spore suspension prior to F. graminearum infection. BN1 also significantly decreased FHB severity when it was sprayed onto wheat heads, whereas BN1 was not effective when wheat heads were point inoculated. These results suggest that spraying of BN1 spores onto wheat heads during the wheat flowering season can be efficient for plant protection. Mechanistic studies on the antagonistic effect of BN1 against F. graminearum remain to be analyzed
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