Year-to-year variations in Bering Sea ice cover and some consequences for fish distributions   总被引：7，自引：0，他引：7  

TINA WYLLIE-ECHEVERRIA  & WARREN S. WOOSTER 《Fisheries Oceanography》1998,7(2):159-170

The southernmost extension of winter ice cover varies interannually and on longer time scales, reflecting large-scale changes in driving forces, especially in the position and intensity of the winter Aleutian Low Pressure System. A conspicuous pattern is alternating warm and cool periods of several years' duration. These variations in sea ice cover are reflected in the character of a subsurface cold pool, formed as stratification isolates the deeper cold waters from surface exchanges. The cold pool is better developed and more extensive in summers that follow deep southward penetration of winter sea ice. Interannual and decadal-scale variations in the distributions of some fish stocks reflect those of ice and thermal conditions. In particular, the distribution of walleye pollock, Theragra chalcogramma, varies significantly with multiannual cool and warm years while Arctic cod, Boreogadus saida, is only present within the cold pool. The relation among climate variations, sea ice cover, subsurface thermal conditions, and fish distribution provides information on how climate affects marine ecosystems and may also have practical application in predicting fish distributions.  相似文献   

Synthesis and testing of novel alternative oxidase (AOX) inhibitors with antifungal activity against Moniliophthora perniciosa (Stahel), the causal agent of witches' broom disease of cocoa,and other phytopathogens     

Mario RO Barsottini  Brbara A Pires  Maria L Vieira  Jos GC Pereira  Paulo CS Costa  Jaqueline Sanit  Alessandro Coradini  Fellipe Mello  Cidnei Marschalk  Eder M Silva  Daniele Paschoal  Antonio Figueira  Fbio HS Rodrigues  Artur T Cordeiro  Paulo CML Miranda  Paulo SL Oliveira  Maurício L Sfora  Marcelo F Carazzolle  Silvana A Rocco  Gonalo AG Pereira 《Pest management science》2019,75(5):1295-1303

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Effects of initial and extended exposure to an endophyte-infected tall fescue seed diet on faecal and urinary excretion of ergovaline and lysergic acid in mature geldings     

CL Schultz  SL Lodge-Ivey  LP Bush  AM Craig  JR Strickland 《New Zealand veterinary journal》2013,61(4):178-184

Abstract

AIM: To determine the amount of ergovaline and lysergic acid retained or excreted by geldings fed endophyte-infected seed containing known concentrations of these alkaloids, and the effects of exposure time on clinical expression of toxicosis.

METHODS: Mature geldings (n=10) received diets containing either endophyte-free (E-) or endophyte-infected (E+) tall fescue seed during three experimental phases. The first phase (Days ?14 to ?1) was an adaptation phase, to allow all horses to adapt to a diet containing E- tall fescue seed. The second (Days 0 to 3) was the initial exposure phase to E+ tall fescue seed, used for the delivery of ergovaline and lysergic acid at 0.5 and 0.3 mg/kg of diet, respectively, to test the initial effects of exposure on routes and amounts of elimination of alkaloid. During this phase, half the geldings were exposed to an E+ diet while the rest served as controls by remaining on the E- diet. Once assigned to treatments, geldings remained on the same diet through the third phase (Days 4 to 21), which served as the extended exposure phase. Total outputs of faeces and urine were collected within each phase, to determine retention of ergovaline and lysergic acid and nutrient digestibility. Serum was collected weekly and analysed for activities of enzymes and concentrations of prolactin. Bodyweights (BW) and rectal temperatures were recorded weekly.

RESULTS: BW, rectal temperature, enzyme activities and concentrations of prolactin in serum, and nutrient digestibility were not affected by treatment. Total intake of ergovaline by geldings on the E+ diet was 3.5 and 3.6 (SE 0.20) mg/day, and 2.1 and 2.3 (SE 0.11) mg/day were not accounted for in initial and extended phases, respectively. Lysergic acid was excreted in the urine (4.0 and 4.9 (SE 0.97) mg/day) and faeces (2.5 and 2.7 (SE 0.35) mg/day) at greater amounts than that consumed (2.0 and 1.9 (SE 0.09) mg/day) during the initial and extended exposure phases, respectively. Animals exposed to E+ seed for a period of 20 days appeared to excrete more (1.5 vs 1.2 mg/day; SE 0.08; p=0.03) ergovaline in the faeces than those exposed for only 4 days.

CONCLUSIONS: Exposure time to the ergot alkaloids had a limited effect on the route of elimination or the amounts of ergovaline or lysergic acid excreted by horses. The primary alkaloid excreted was lysergic acid, and urine was the major route of elimination. These data will aid future research to improve animals′ tolerance to toxic endophyte-infected tall fescue.  相似文献   

Copper deficiency in sheep: An assessment of the relationship between concentrations of copper in serum and plasma     

RA Laven  SL Smith 《New Zealand veterinary journal》2013,61(6):334-338

AIM: To assess the relationship between concentrations of copper in serum and plasma in sheep.

METHODS: Concentrations of Cu were measured in paired serum and heparinised plasma samples collected from 110 sheep in nine flocks. Linear regression was used to evaluate whether flock or gender had a significant effect on the association between concentrations of Cu in serum and plasma. The individual results for concentrations of Cu in serum were then compared with those from plasma, using correlation and limits of agreement plotting.

RESULTS: Concentrations of Cu in serum ranged from 7.3 to 22 (mean 14.0) µmol/L, while concentrations in plasma ranged from 9 to 27 (mean 16.3) µmol/L. On average, concentrations of Cu in serum were 2.3 µmol/L lower than in plasma. Over the range of values seen in this study, concentrations of Cu in plasma and serum were significantly correlated (r=0.89), and mean concentrations in serum were 87% of those in plasma. There was no effect of flock or gender on the relationship between concentrations of Cu in serum and plasma. Despite the significant correlation, there was marked variability between individual samples in the proportion of Cu that was lost during clotting, with the 95% limits of agreement for serum Cu ranging from 70 to 104% of the plasma concentration.

CONCLUSIONS: As in cattle, the individual variability in the loss of Cu during clotting in sheep is too great for concentration of Cu in serum to be used as a substitute for that in plasma.

CLINICAL RELEVANCE: When assessing the blood Cu pool as part of the diagnosis of Cu-responsive disease in sheep, the concentration of Cu in plasma should be measured in preference to that of serum. We suggest that a range of 4.5 to 9 µmol/L in plasma be used to define marginal Cu status in sheep.  相似文献   

Effect of density on brood size in noble crayfish,Astacus astacus L., subjected to indoor rearing conditions*     

T. TAUGB SL  J. SKURDAL 《Aquaculture Research》1990,21(1):17-23

Abstract. The effects of density, cover, and individual versus communal holding on brood size and female survival during the breeding period were examined in a large-scale experiment, involving 3591 mature noble crayfish, Astacus astacus L., females. Crayfish density during both mating/spawning and winter incubation had major effects on egg survival. In the high density experiment (67 and 44 individuals per m² during mating/spawning and winter incubation respectively) mean pleopod egg number in April was 18-20. Lowering the density to 50 during mating/spawning (still 44 individuals per m² during winter incubation) gave mean pleopod egg numbers of 31-38. In the low density experiment (50 and 33 individuals per m² during mating/spawning and winter incubation) mean pleopod egg numbers were 44-46. Egg-bearing females held in individual compartments with perforated bottom had a mean pleopod egg number of 25. Female survival during winter incubation was high, ranging from 91.8 to 98.3%. Covering the basins had no distinct effect on egg and female survival. In Astacus astacus culture we recommend that crayfish density should not exceed about 50 individuals per m² during mating/spawning and about 33 individuals per m² during winter incubation.  相似文献   

Mammary neoplasia in common brushtail possums: case report and retrospective identification of additional cases     

L Setyo  SL Donahoe  K Rose  D Spielman 《Australian veterinary journal》2020,98(6):243-246

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Neighborhood Exposure to Toxic Releases: Are There Racial Inequities?     

WARREN KRIESEL  TERENCE J. CENTNER  ANDREW G. KEELER 《Growth and change》1996,27(4):479-499

This paper explores the use of empirical evidence to determine whether the exposure of minorities to environmental risks constitutes aversive racism. Connections are drawn between definitions of aversive racism and statistical approaches to research into the relationship between race and risk, paying particular attention to the influence of both non-racial discrimination and industrial location factors. Federal judicial and executive remedies to aversive racism are examined in light of the standards of evidence presented. An empirical study of the connection between race and exposure to toxic releases is then presented for Census block groups in Georgia and Ohio. It was found that the significance of race depends on the breadth of the explanatory model used in the analysis. A model of overall exposure to toxic releases shows that race is significant in a narrow model of discrimination but not in a broader model including industrial location factors. However, a model of targeting of minorities in the recent location of toxics-emitting facilities fails to show discrimination in any of the regression analyses. These findings support the view that environmental justice concerns cannot be addressed through reform of siting processes; broader remedies involving more stringent protection of exposure to toxic emissions are more likely to be effective.  相似文献   

Natural infection of wild doves (Streptopelia senegalensis) with the virus of psittacine beak and feather disease     

DA PASS  SL PLANT  N. SEXTON 《Australian veterinary journal》1994,71(9):307-308

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Biological availability of strontium-90 from atomic tests     

BRYANT EA  COWAN GA  HEALD WR  MENZEL RG  REITEMEIER RF  SATTIZAHN JE  WARREN B 《Science (New York, N.Y.)》1960,132(3423):327-330

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Preference aversion in mice to bitter substance     

WARREN RP 《Science (New York, N.Y.)》1963,140(3568):808-809

Preference-aversion functions demonstrable for sweet and salty stimuli have been found for a "bitter" substance, sucrose octaacetate, at individually specific concentrations for mice. The data support Schneirla's views correlating stimulus magnitudes and approach-withdrawal. The positive reinforcing value of this bitter substance as a weak stimulus is diminished with continuous exposure and no secondary reinforcement. Avoidance is related to intensity of stimulation rather than modality or postingestion effects.  相似文献