The effect of salinity on growth and survival of juvenile black bream (Acanthopagrus butcheri)     

Gavin J. Partridge  Greg I. Jenkins 《Aquaculture (Amsterdam, Netherlands)》2002,210(1-4):219-230

Growth and survival of juvenile black bream (Acanthopagrus butcheri) were determined at salinities from 0 to 60 ppt (in 12-ppt increments) and from 0 to 12 ppt (in 4-ppt increments) in two separate trials of 6 and 4 months duration, respectively. Juvenile black bream were able to survive and grow at salinities ranging from freshwater (0 ppt) to 48 ppt. Osmotic stress was evident at 60 ppt, however, survival was not significantly affected. Fish reared at 24 ppt in trial 1 had a specific growth rate of 2.34±0.03%/day, a rate significantly higher only to those fish reared at 60 ppt (2.16±0.04%/day). Growth was greater at 24 ppt in association with the highest food intake and most efficient FCR. Although both food intake and FCR were not significantly higher than those obtained with fish reared at 12, 36 and 48 ppt, the combination of the two factors being optimised at 24 ppt lead to the greatest growth. Analysis of data from the second trial found no significant difference in the growth rate of black bream reared at salinities ranging from freshwater to 12 ppt, with SGR ranging from 1.92±0.05%/day to 2.05±0.02%/day. Variable results in freshwater between the two trials suggested that total hardness of freshwater may influence survival and/or an ontogenetic change in salinity tolerance may occur.  相似文献   

Pleistocene Park: Does re-wilding North America represent sound conservation for the 21st century?     

Dustin R. Rubenstein  Daniel I. Rubenstein  Thomas A. Gavin 《Biological conservation》2006,132(2):232-238

A group of conservation biologists recently proposed to populate western North America with African and Asian megafauna, including lions, elephants, cheetahs, and camels, to create a facsimile of a species assemblage that disappeared from the continent some 13,000 years ago. The goals of this program, known as “Pleistocene re-wilding”, are to restore some of the evolutionary and ecological potential that was lost from North America during the Pleistocene extinctions, and help prevent the extinction of selected African and Asian mammals. Pleistocene re-wilders justify this conservation strategy on ethical and aesthetic grounds, arguing that humans have a moral responsibility to make amends for overexploitation by our ancestors. They believe that the flora of many North American terrestrial ecosystems has gone basically unchanged since the end of the Pleistocene, so re-wilding would help restore evolutionary and ecological potential and improve ecosystem functioning. This paper discusses some of the pros and cons of this proposal, including the ethical, aesthetic, ecological, and evolutionary issues, assesses its potential economic and political impacts on other conservation practices, both in North America and elsewhere, and reviews the realities of large mammal reintroductions. It is concluded that Pleistocene re-wilding with exotic species will not restore the evolutionary or ecological potential of native North American species nor extinct Pleistocene megafauna and their ancient ecosystems, but may instead jeopardize indigenous species and North American ecosystems. Resources would be better spent on preserving threatened organisms in their native habitats and reintroducing them to places in their historical ranges from which they were only recently extirpated.  相似文献   

Measuring socio-economic position in dietary research: is choice of socio-economic indicator important?     

Turrell G  Hewitt B  Patterson C  Oldenburg B 《Public health nutrition》2003,6(2):191-200

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Aerobic metabolism of diclosulam on U.S. and South American soils     

Yoder RN  Huskin MA  Kennard LM  Zabik JM 《Journal of agricultural and food chemistry》2000,48(9):4335-4340

Degradation of the sulfonanilide herbicide diclosulam was studied on nine soils from three countries to determine the rates and products of aerobic metabolism. Diclosulam was applied to four agricultural soils from the United States, three from Argentina, and two from Brazil at a rate of 0.1 ppm, equivalent to approximately twice the maximum field application rate of 52 g of active ingredient/ha. U.S. and Brazilian soils were incubated in the dark at 25 degrees C at 75% 0.3 bar moisture; Argentinean soils were incubated in the dark at 20 degrees C and 45% moisture holding capacity. Samples were analyzed up to one year after treatment. Two-compartment DT(50) and DT(90) values averaged 28 +/- 12 and 190 +/- 91 days, respectively. Three soil metabolites reached levels of >10% of applied in at least one soil and were identified as the 5-hydroxy analogue of diclosulam (5-OH-diclosulam), aminosulfonyl triazolopyrimidine (ASTP), and the 8-chloro-5-hydroxy analogue of diclosulam (8-Cl-diclosulam). The terminal products of diclosulam soil metabolism were mineralization to CO(2) and bound soil residues. Apparent sorption coefficients (K(d)) were determined on a subset of samples by extraction with a 0. 01 M CaCl(2) solution followed by an acidified acetone extraction. Initial sorption coefficients were similar to those obtained in a batch equilibrium study and averaged 1.1 L/kg for the six soils tested. K(d) coefficients for the metabolites, when available, tended to be slightly lower than that for diclosulam. Sorptivity of diclosulam and degradates increased with time.  相似文献   

Mycorrhizal diversity: Cause and effect?   总被引：2，自引：0，他引：2  

Gavin Kernaghan   《Pedobiologia》2005,49(6):3545-520

Mycorrhizal fungi play a critical role in nutrient cycling and ecosystem function. They improve plant growth and survival through a mutualistic relationship in which photosynthates are exchanged for increased access to water and nutrients. Because the benefits realized are not equal among different plant–fungal species combinations, mycorrhizal fungi may help govern plant community structure and successional trajectories. In fact, both plant productivity and plant diversity have been shown to increase with increasing diversity of mycorrhizal fungi. The diversity and species composition of plant communities also exert a reciprocal influence on associated mycorrhizal communities, although edaphic factors may also play a role. Given this inherent bi-directionality of mycorrhizal relationships, the potential exists for positive feedback mechanisms which may promote and maintain both plant and mycorrhizal fungal diversity. This review considers recent literature on both arbuscular and ectomycorrhizal fungal–plant community relationships within a variety of environments, including artificially constructed systems and naturally occurring grasslands and forests.  相似文献   

Complementary foods in Jamaica: viscosity,energy density and feeding practices     

Gardne JM  Walker SP  Gavin KA  Ashworth A 《Public health nutrition》2002,5(2):295-302

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A CUTANEOUS TEST FOR TUBERCULOSIS IN PRIMATES     

Kennard MA  Schroeder CR  Trask JD  Paul JR 《Science (New York, N.Y.)》1939,89(2315):442-443

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Complex I binding by a virally encoded RNA regulates mitochondria-induced cell death     

Reeves MB  Davies AA  McSharry BP  Wilkinson GW  Sinclair JH 《Science (New York, N.Y.)》2007,316(5829):1345-1348

Human cytomegalovirus infection perturbs multiple cellular processes that could promote the release of proapoptotic stimuli. Consequently, it encodes mechanisms to prevent cell death during infection. Using rotenone, a potent inhibitor of the mitochondrial enzyme complex I (reduced nicotinamide adenine dinucleotide-ubiquinone oxido-reductase), we found that human cytomegalovirus infection protected cells from rotenone-induced apoptosis, a protection mediated by a 2.7-kilobase virally encoded RNA (beta2.7). During infection, beta2.7 RNA interacted with complex I and prevented the relocalization of the essential subunit genes associated with retinoid/interferon-induced mortality-19, in response to apoptotic stimuli. This interaction, which is important for stabilizing the mitochondrial membrane potential, resulted in continued adenosine triphosphate production, which is critical for the successful completion of the virus' life cycle. Complex I targeting by a viral RNA represents a refined strategy to modulate the metabolic viability of the infected host cell.  相似文献   

Canadian Power Stations and the National Pollutant Release Inventory (NPRI): A Success Story for Pollution Intensity?     

Minmeng Tang  Gavin M. Mudd 《Water, air, and soil pollution》2014,225(10):1-17

This paper presents a comprehensive analysis of the pollutant emissions and intensity from Canada’s power stations. An analysis of National Pollutant Release Inventory (NPRI) and site generation data shows significant variability with the dominant emissions pathway being point-source air emissions. In general, power stations are a very small fraction of Canada’s direct facility and estimated diffuse emissions, as well as showing significant variability of pollutant intensities per megawatt or megawatt hour of capacity or generation. The evidence also suggests that increased scale does not lead to a lower pollutant intensity, and that transfers and disposal pollutant loads are substantial, often representing most of the total reported pollutants. Overall, this study provides a valuable insight into the current status of pollutant intensities from Canada’s power stations, possible improvements to the NPRI and a valuable benchmark for future studies and international comparisons.  相似文献   

An antigen produced by splicing of noncontiguous peptides in the reverse order     

Warren EH  Vigneron NJ  Gavin MA  Coulie PG  Stroobant V  Dalet A  Tykodi SS  Xuereb SM  Mito JK  Riddell SR  Van den Eynde BJ 《Science (New York, N.Y.)》2006,313(5792):1444-1447

CD8-positive T lymphocytes recognize peptides that are usually derived from the degradation of cellular proteins and are presented by class I molecules of the major histocompatibility complex. Here we describe a human minor histocompatibility antigen created by a polymorphism in the SP110 nuclear phosphoprotein gene. The antigenic peptide comprises two noncontiguous SP110 peptide segments spliced together in reverse order to that in which they occur in the predicted SP110 protein. The antigenic peptide could be produced in vitro by incubation of precursor peptides with highly purified 20S proteasomes. Cutting and splicing probably occur within the proteasome by transpeptidation.  相似文献