Publications by authors named "Knights B"

Understanding the movement patterns of an invasive species can be a powerful tool in designing effective management and control strategies. Here, we used a Bayesian multistate model to investigate the movement of two invasive carp species, silver carp () and bighead carp (), using acoustic telemetry. The invaded portions of the Illinois and Des Plaines Rivers, USA, are a high priority management zone in the broader efforts to combat the spread of invasive carps from reaching the Laurentian Great Lakes.

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Movement and dispersal of migratory fish species is an important life-history characteristics that can be impeded by navigation dams. Although habitat fragmentation may be detrimental to native fish species, it might act as an effective and economical barrier for controlling the spread of invasive species in riverine systems. Various technologies have been proposed as potential fish deterrents at locks and dams to reduce bigheaded carp (i.

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Similarity in community composition declines as distance between locations increases, a phenomenon that has been observed in a wide variety of freshwater, marine and terrestrial ecosystems. One driver of the distance-similarity relationship is the presence of environmental gradients that alter the suitability of sites for particular species. Although some environmental gradients, such as geology, do not change on a year-to-year basis, others, such as temperature, vary annually and over longer time periods.

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Mercury (Hg) contamination of fisheries is a major concern for resource managers of many temperate lakes. Anthropogenic Hg contamination is largely derived from atmospheric deposition within a lake's watershed, but its incorporation into the food web is facilitated by bacterial activity in sediments. Temporal variation in Hg content of fish (young-of-year yellow perch) in the regulated lakes of the Rainy-Namakan complex (on the border of the United States and Canada) has been linked to water level (WL) fluctuations, presumably through variation in sediment inundation.

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Spatial variation in food resources strongly influences many aspects of aquatic consumer ecology. Although large-scale controls over spatial variation in many aspects of food resources are well known, others have received little study. Here we investigated variation in the fatty acid (FA) composition of seston and primary consumers within (i.

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It is widely accepted that climate change poses severe threats to freshwater ecosystems. Here we examine the scientific basis for adaptively managing vulnerable habitats and species. Our views are shaped by a literature survey of adaptation in practice, and by expert opinion.

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Possible causes of declines in recruitment of European, American and Japanese eels to continental waters are reviewed. Negative correlations between the Den Oever glass eel recruitment index (DOI) and the North Atlantic Oscillation Index since 1938 are discussed, together with older anecdotal evidence. Correlations are established between the DOI and sea surface temperature anomalies at 100-250 m between 1952 and 1995 in the Sargasso Sea/Sub-Tropical Gyre (STG) spawning area.

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Three children with faecal incontinence, in whom conventional treatment had failed, were managed with a regimen that focuses on the symptoms and present behaviour. It is short term and uses a paradoxical approach.

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1. The urinary and biliary excretion of 14C-labelled m-cresol, 1-naphthol and o-chlorophenol were investigated in 12 species of freshwater fish (bitterling, Rhodeus sericeus amarus; bream, Abramis brama; crucian carp, Carassius carassius; goldfish, Carassius auratus; gudgeon, Gobio gobio; guppy, Poecilia reticulata; minnow, Phoximus phoximus; perch, Perca fluviatilis; roach, Rutilus rutilus; rudd, Scardinius erythropthalmus; three-spined stickleback, Gasterosteus aculeatus; tench, Tinca tinca) when immersed in sub-lethal concentrations of the compounds in the aquarium water for 48 h. 2.

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1. An investigation was carried out on the hydrolytic activity of the intestinal mucus/flora on phenylglucuronide in the bile of goldfish. 2.

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When cholesterol, cholesteryl palmitate and cholesteryl acetate were added individually to sterol-free cultures ofPhytophthora cactorum, the free sterol was at first taken up more rapidly. By 24 hr, the uptake of esters and free sterol was similar. The 2 esters apparently are taken up by different mechanisms, since much acetate was found in extracts of the mycelium at early harvests, but very little palmitate.

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Sterols of male and female flowers of Cucumis sativus L. were similar in composition. The principal compound was 24ξ-ethyl-5α-cholesta-7,22-dien-3β-ol.

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delta7- and delta5,7-Sterols are converted to the corresponding delta5-sterols by Phytophthora cactorum. When delta7-sterols were supplied to the fungus, delta5- and delta7-sterols were recovered in an acetone extract of the mycelium, the proportion of delta5-sterol being higher in the free sterol fraction than in the esters. When delta5,7-sterols were supplied, delta5-sterols were recovered.

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A comparison has been made between the sterols of male and female inflorescences and of pollen from Zea mays. The female inflorescence was shown to contain cholesterol, 24-methylcholesterol, 24-ethyl-5,22-cholestadien-3β-ol, 24-ethylcholesterol and (28Z)-24-ethylidenecholesterol. Themale inflorescence contained the same five compounds together with 24-methylenecholesterol.

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Bayol F preparations from different commercial sources were incorporated into water-in-oil emulsions containing mycobacterial fractions and a protein antigen. It was found that an adjuvant effect was obtained with some mineral oils and a toxic immunosuppressive effect with others.

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We used high-resolution glass capillary columns to study the trimethylsilyl derivatives of some acidic metabolites found in pooled urine specimens form control and postpartum subjects. About 30 compounds were identified by gas chromatography-mass spectrometry-computer techniques. In general, open tubular capillary columns effect better resolution of trimethylsilyl derivatives of organic acids than do conventional packed columns.

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Abscisic acid was detected by gas-liquid chromatography of the methyl esters in the acid fraction of extracts from leaves of juvenile and adult Hedera helix L. Combined gas chromatography-mass spectrometry data were obtained for the extract of adult tissues and thin-layer chromatography, gas-liquid chromatography and gas chromatography-mass spectrometry data for that of juvenile tissues. An estimation of the amounts of abscisic acid present in extracts from both growth phases was carried out using a single ion monitoring technique.

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