36,924 research outputs found

    Distributed lag models for hydrological data

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    The distributed lag model (DLM), used most prominently in air pollution studies, finds application wherever the effect of a covariate is delayed and distributed through time. We explore the use of modified formulations of DLMs to provide flexible varying-coeficient models with smoothness constraints, applicable in any setting in which lagged covariates are regressed on a time-dependent response. The models are applied to simulated flow and rainfall data and to flow data from a Scottish mountain river, with particular emphasis on approximating the relationship between environmental covariates and flow regimes in order to detect the influence of unobserved processes. It was found that under certain rainfall conditions some of the variability in the influence of rainfall on flow arises through a complex interaction between antecedent ground wetness and the time-delay in rainfall. The models are able to identify subtle changes in rainfall response, particularly in the location of peak influence in the lag structure and offer a computationally attractive approach for fitting DLMs

    Persistent, symptomless, systemic, and seed-borne infection of lettuce by Botrytis cinerea

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    Experiments are presented which show that Botrytis cinerea, the cause of gray mould disease, is often present in symptomless lettuce plants as a systemic, endophytic, infection which may arise from seed. The fungus was isolated on selective media from surface sterilized sections of roots, stem pieces and leaf discs from symptomless plants grown in a conventional glasshouse and in a spore-free air-flow provided by an isolation propagator. The presence of B. cinerea was confirmed by immuno-labelling the tissues with the Botrytis-specific monoclonal antibody BC-12.CA4. As plants grew, infection spread from the roots to stems and leaves. Surface sterilization of seeds reduced the number of infected symptomless plants. Artificial infection of seedlings with dry conidia increased the rate of infection in some experiments. Selected isolates were genetically finger-printed using microsatellite loci. This confirmed systemic spread of the inoculating isolates but showed that other isolates were also present and that single plants hosted multiple isolates. This shows that B. cinerea commonly grows in lettuce plants as an endophyte, as has already been shown for Primula. If true for other hosts, the endophytic phase may be as important a component of the species population as the aggressive necrotrophic phase

    Rainfall and runoff: hydrological studies in Weardale

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    Experimental evaluation of shockless supercritical airfoils in cascade

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    Surface Mach number distributions, total pressure loss coefficients, and schlieren images of the flow are presented over a range of inlet Mach numbers and air angles. Several different trailing edge geometries were tested. At design conditions a leading edge separation bubble was observed resulting in higher losses than anticipated. The minimum losses were obtained at a negative incidence condition in which the flow was accelerating over most of the supercritical region. Relatively minor differences in losses were measured with the different trailing edge geometries studied

    1863-03-06 Lieutenant E.M. Shaw to Adjutant General Hodsdon regarding orders

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    https://digitalmaine.com/cw_me_10th_regiment_corr/1011/thumbnail.jp

    1863-02-23 Lieutenant E.M. Shaw to Adjutant General Hodsdon asking for position as Provost Marshal

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    https://digitalmaine.com/cw_me_10th_regiment_corr/1008/thumbnail.jp

    1863-02-16 Letter from Lieutenant E.M. Shaw

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    https://digitalmaine.com/cw_me_10th_regiment_corr/1007/thumbnail.jp

    1863-03-03 Lieutenant E.M. Shaw to Adjutant regarding monthly return

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    https://digitalmaine.com/cw_me_10th_regiment_corr/1010/thumbnail.jp

    1863-03-01 Lieutenant E.M. Shaw to General regarding Edward Brackett bounty receipt

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    https://digitalmaine.com/cw_me_10th_regiment_corr/1009/thumbnail.jp
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