Megninia ginglymura feather mites from a captive piping-guan (Pipile pipile)     

Ménier K  Brown G  Cooper JE 《The Veterinary record》2007,160(26):909-910

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Some vocabulary and grammar for the analysis of multi-environment trials, as applied to the analysis of FPB and PPB trials   总被引：2，自引：0，他引：2  

F.A. van Eeuwijk  M. Cooper  I.H. DeLacy  S. Ceccarelli  S. Grando 《Euphytica》2001,122(3):477-490

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Reverse-phase liquid chromatographic determination of benzoic and sorbic acids in foods     

L V Bui  C Cooper 《Journal of the Association of Official Analytical Chemists》1987,70(5):892-896

An isocratic liquid chromatographic (LC) technique is described for the determination of benzoic acid and sorbic acid in foods such as beverages, fruits, seafood, vegetables, sauces, and dairy, bakery, and confectionery products. A C18 column is used with methanol-phosphate buffer (5 + 95) as mobile phase and 4-hydroxyacetanilide or 3,5-dinitrobenzoic acid as internal standard. Sample preparation is simple, rapid, and produces a sample extract that has a minimum effect on the column performance and life. Specificity of the method was checked against common food additives such as L-ascorbic acid, caffeine, artificial sweeteners (saccharin, cyclamate, aspartame), antioxidants (BHT, BHA) and artificial colors. Also described are 2 procedures for confirmation of the preservatives, using either redox reaction of sorbic acid with potassium permanganate or gas chromatography/mass spectrometry. Mean recoveries of 90-105% were obtained with a precision of 1-6% and a detection limit of 20 mg/kg for the 2 preservatives.  相似文献   

Fate of a phenylpyrazole in vegetation and soil under tropical field conditions     

Fenet H  Beltran E  Gadji B  Cooper JF  Coste CM 《Journal of agricultural and food chemistry》2001,49(3):1293-1297

The fate of fipronil, a phenylpyrazole insecticide, and its metabolites under tropical conditions was studied in soil and in vegetation after treatment for locust control. Two different plots were treated with a formulation of fipronil at doses of 5 and 10 g of active ingredient ha(-)(1), respectively. Vegetation and soil at depths of 0-5 and 5-20 cm were sampled for up to 2 months after treatment. After extraction and purification on fipronil immunoaffinity cartridges, residues were analyzed by gas chromatography using electron capture and mass detectors. In soil, a rapid initial decrease of fipronil was observed with a rapid formation of the sulfone and the photodegradate; the amide and the sulfide were not detected. In vegetation, a rapid initial decrease of fipronil was also observed with a rapid formation of mostly the sulfone; the photodegradate and the sulfide were also detected but at much lower concentrations. The metabolites resulting from the degradation of fipronil were similar in both soil and vegetation, but their relative concentrations were different.  相似文献   

Use of a population model to assess the impact of longline fishing on wandering albatross Diomedea exulans populations     

Coleen L. Moloney  John Cooper  Peter G. Ryan  W. Roy Siegfried 《Biological conservation》1994,70(3):195-203

An age-structured model of a wandering albatross Diomedea exulans population is developed to stimulate population trends over time, using demographic parameters from the population at Possession Island, Crozets, during 1968–1986. The simulation results portray a population decreasing at a rate of 2·29% per year, which concurs with global population trends. Sensitivity analyses of model parameters indicate that both adult and juvenile mortality are contributing to the decrease. Wandering albatross mortality is presumed to have increased as a result of deaths caused by longline fishing vessels; such deaths are likely to be relatively more frequent among young, naive birds. The model is used to investigate the potential impacts of new longline fisheries such as that for Patagonian toothfish Dissostichus eleginoides in Antarctica. Assuming longline fishing operations affect juveniles more than adults, there is a time lag of 5–10 years before further decreases in population numbers are reflected in the breeding population. Also, because wandering albatrosses are long-lived, population growth rates take approximately 30–50 years to stabilize after a perturbation. Consequently, caution must be exercised when interpreting population trends; short-term (<20 year) estimates may not provide good indications of long-term trends.  相似文献   

Application of multivariate methods to the conservation management of Hazel scrub in northeast Ireland     

Alan Cooper 《Biological conservation》1984,30(4):341-357

The plant species composition of seminatural woods in Northeast Ireland was recorded. Three main types of woodland were identified in habitats where combinations of steep slope, poor drainage and accumulations of large boulders have, in the past, made them unsuitable for agriculture. Despite these characteristics, clearance for agriculture is proceeding rapidly, but mainly in woods from poorly drained sites. Badly drained woods also have a relatively higher proportion of regionally rare plant species and there is, therefore, an argument for some priority for their conservation.

The population size-structures of trees were used to predict future changes in canopy composition, possibly originating from the introduction of myxomatosis to Ireland. Such changes may give rise to management problems associated with canopy closure and a subsequent reduction of species diversity.  相似文献   

Aluminium toxicity and multiplication of Rhizobium trifolii in a defined growth medium     

M. Wood  J.E. Cooper 《Soil biology & biochemistry》1984,16(6):571-576

The responses of six strains of R. trifolii to pH, Ca, Al and phosphate were studied in the defined medium of Munns and Keyser (1981) supplemented with vitamins. Wild-type strains responded in the same way as rifampicin-resistant mutant strains. Multiplication was inhibited by acidity alone at pH4.3, and by 50 μM Al at pH 5.5 (despite the precipitation of Al). This inhibitory effect of Al was overcome by increasing the pH above 6.0, or by increasing the phosphate concentration from 10 to 100 μm. Ca concentration had no effect, nor did holding the medium at 22°C for 36 weeks before inoculation. There was variation between strains in their responses to concentrations of A1 < 50 μM. These responses indicate that the defined medium is a satisfactory model for the white clover rhizosphere.Results from these studies and from chemical analyses indicate that the inhibitory effect of Al under partially-neutralized conditions is not due to a direct effect of monomeric A1, nor to an indirect effect of polymeric A1 in reducing the concentration of phosphate, but is due to a direct effect of polymeric A1.  相似文献   

Combined effects of best management practices on water quality in oxbow lakes from agricultural watersheds     

R.F. Cullum  S.S. Knight  C.M. Cooper  S. Smith 《Soil & Tillage Research》2006,90(1-2):212-221

Water quality conditions in three oxbow lakes were examined before and after best management practices (BMPs) implementation within the Mississippi Delta. Experimental design called for the development of structural and cultural treatments to reduce sediment and associated pollutants entering watershed oxbow lakes. Three watersheds were selected and developed with different levels of BMPs. Changes in lake water quality were used as measures of management success. Analyses of water quality data prior to the implementation of BMPs suggested the lakes were stressed and ecologically damaged due to excessive sediment inflow. Significant improvements in water quality were observed with the use of cultural and structural BMPs. Sediments decreased 34–59%, while Secchi visibility and chlorophyll generally increased. The most dramatic improvements in water quality occurred in the two watersheds that featured cultural practices and combinations of cultural and structural practices. Reducing suspended sediment concentrations in these oxbow lakes favored phytoplankton production resulting in increased chlorophyll concentrations and higher concentrations of dissolved oxygen. Cultural BMPs, more so than structural BMPs, play a vital role in improving lake water quality, and are needed in addition to structural measures to ensure improved water quality in oxbow lakes receiving agricultural runoff.  相似文献   

Effects of thiopental sedation on learning and memory   总被引：1，自引：0，他引：1  

A G Osborn  J P Bunker  L M Cooper  G S Frank  E R Hilgard 《Science (New York, N.Y.)》1967,157(788):574-576

Subjects who were administered thiopental showed a loss of memory for events discussed while they were under sedation. We tested the subjects for recognition memory of pictures and recall of associated pairs of letters and words, and found that the subsequent memory loss was correlated with the concentration of thiopental in the venous blood at the time the material was learned. Retention did not appear to be state-dependent because the subject, while under sedation, could recall material learned prior to sedation, and because recall was not facilitated by reinstatement of the sedation.  相似文献   

A physiological basis for a theory of synapse modification   总被引：22，自引：0，他引：22  

M F Bear  L N Cooper  F F Ebner 《Science (New York, N.Y.)》1987,237(4810):42-48

The functional organization of the cerebral cortex is modified dramatically by sensory experience during early postnatal life. The basis for these modifications is a type of synaptic plasticity that may also contribute to some forms of adult learning. The question of how synapses modify according to experience has been approached by determining theoretically what is required of a modification mechanism to account for the available experimental data in the developing visual cortex. The resulting theory states precisely how certain variables might influence synaptic modifications. This insight has led to the development of a biologically plausible molecular model for synapse modification in the cerebral cortex.  相似文献