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71.
H D Blackburn J L Rocha E P Figueiredo M E Berne L S Vieira A R Cavalcante J S Rosa 《Veterinary parasitology》1991,40(1-2):99-112
Weaned wether goats (n = 144) approximately 6 months of age were placed in a 2 x 3 factorial design experiment for 5 months to test the main effects and interaction of two levels of nutrition (growth + maintenance, NUT1; twice growth + maintenance, NUT2) and three levels of Haemonchus contortus burden (0, 500 and 2000 larvae administered every 2 weeks: W0, W500 W2000, respectively) on weight, feed intake, level of infection and packed cell volume (PCV). The rationale for the experimental design was based on the lack of information concerning the interaction between nutritional status and worm burden. Results indicated significant effects of worm burden levels on PCV, faecal egg contents (eggs per gram of feces (EPG)), actual worm numbers, feed intake and efficiency of feed utilization. Nutrition x worm burden interactions were also significant for PCV and EPG. However, the differences detected for PCV and actual worm numbers did not translate into large or consistent differences in body weight. Goats on NUT2, after an initial period, showed little difference in body weight, irrespective of worm burden. Within the NUT1 level, W0 kids weighed more than W500 or W2000 kids throughout the study. Although not statistically significant, this constitutes a trend towards an interaction between nutrition and worm burden. In both nutrition levels, there were no body weight differences between W500 and W2000 until the last 14 days. Feed intake was depressed in the first 3 months of the experiment for infected animals, but was subsequently followed by a compensatory reaction. Lower establishment rates, based on actual worm counts, were observed for the higher infection level, but in both infection levels establishment rates tended to decrease with time. Nutrition was found to be more important to counteract the consequences of a parasitic infection than to counteract the establishment of that same infection. 相似文献
72.
Ochratoxin A is a metabolite produced by Aspergillus and Penicillium species that is nephrotoxic and possibly carcinogenic to humans. The aim of this study was to evaluate ochratoxin A contamination in green coffee obtained by different harvesting and drying operations and from fruits of different ripening stages in order to identify hazards. The research was directed to coffees from the highland area of Rio de Janeiro state (Brazil), which is traded in the domestic market. Twenty-two out of 54 samples contained ochratoxin A at levels ranging from 0.3 to 160 microg/kg. Ochatoxin A contamination levels between different ripe stage fruits were not significant (P > 0.05). "Varri??o" coffee, consisting of fruits that fell from the tree spontaneously and stayed longer on the ground before being harvested, was the most contaminated. Eleven out of 14 samples of varri??o coffee were contaminated. Three out of 10 samples from the northwestern region of the state were positive for ochratoxin at levels ranging from 10.1 to 592 microg/kg. The contaminated samples had in common the fact that they were harvested directly from the soil. 相似文献
73.
Habitat mapping at the scale at which marine protected areas are designed and managed is essential for assessment of, and design for, representation. Most habitat mapping studies rely solely or in part on abiotic surrogates for patterns of biodiversity. The utility of abiotic variables in predicting biological distributions at the local scale (10 s of km) was tested in a remote video survey of macrobenthos in Moreton Bay, Australia. Habitat classifications of the same set of 41 sites based on 6 abiotic variables and abundances of 89 taxa and bioturbation indicators were compared using correlation, regression and ordination analyses. The concepts of false homogeneity (abiotically similar but biologically distinct) and false heterogeneity (abiotically distinct but biologically similar) were defined to describe types of errors associated with using abiotic surrogates to construct habitat maps, and quantified using two separate methods. Overall, the best prediction by abiotic surrogates explained less than 30% of the pattern of biological similarity. Errors of false homogeneity were between 20% and 62%, depending on the methods of estimation. Predictive capability of abiotic surrogates at the taxon level was poor, with only 6% of taxon/surrogate correlations significant. Abiotic variables did not discriminate sufficiently between different soft bottom communities to be a reliable basis for mapping. These results have implications for the widespread use of abiotic surrogates in marine habitat mapping to plan for, or assess, representation in marine protected areas. Little confidence can be placed in marine habitat classifications based solely or largely on abiotic surrogates without calibration by rigorous biological surveys at the appropriate scale. Therefore, it is questionable whether marine protected areas designed on this basis can have measurable benefits for conservation. 相似文献
74.
Doblado R Zielinski H Piskula M Kozlowska H Muñoz R Frías J Vidal-Valverde C 《Journal of agricultural and food chemistry》2005,53(4):1215-1222
Cowpea (Vigna sinensis L. var. Carilla) flours obtained by fermentation with inoculum Lactobacillus plantarum (PF) or with the natural microorganisms present in the flour (NF) and subsequent heat treatment in an autoclave were prepared to study the effect of fermentation on the antioxidant vitamin content and on the antioxidant capacity. Bacterial counts and pH values, vitamins C and E, carotenoids, glutathione (GSH), superoxide dismutase-like activity (SOD-like activity), peroxyl radical-trapping capacity (PRTC), lipid peroxidation in unilamillar liposomes, and Trolox equivalent antioxidant capacity (TEAC) were evaluated in raw and processed cowpea flours. gamma-Tocopherol and delta-tocopherol were found in raw cowpea, whereas vitamin C and carotenoids were not detected. An increase in the vitamin E activity was observed in PF, whereas vitamin C and carotenoids were not detected in fermented cowpea flours. Fermentation or heat treatment in an autoclave after fermentation produced processed cowpea flours with lower PRTC, glutathione content, and SOD-like activity than those of the raw seeds. However, those processes increased the capacity to inhibit the lipid peroxidation in unilamellar lipoposomes and TEAC. According to the results obtained in this study, the fermentation of cowpeas (naturally or with L. plantarum) and fermentation and subsequent heat treatment in an autoclave are good processes to obtain functional cowpea flours having higher antioxidant capacity than the raw legume. 相似文献
75.
Short-term survival and dispersal of translocated European wild rabbits. Improving the release protocol 总被引:1,自引:0,他引:1
Translocation of European wild rabbit Oryctolagus cuniculus L. is one of the most frequent management tools to increase rabbit density in Spain, both as prey of several predators that are threatened with extinction and for sport hunting. Nevertheless the elevated short-term mortality by predation makes translocations unsuccessful and increases their biological cost. Information on the factors affecting the short-term survival and dispersal of translocated rabbits is required to improve release management and increase performance of translocated rabbits, and to avoid the use of non-selective lethal methods for predator control. In this study we tested electric fencing and night-shooting as alternative to traditional release protocols, and the effects of vegetation cover and warren fencing on short-term survival and dispersal of rabbits. Night shooting performed during the first nights after release increased significantly the survival of rabbits, by hindering the activity of carnivores in the release area. The use of an electric fence enclosure also increased the performance of rabbits, but was not efficient to constraint rabbit dispersal. Rabbits released in areas with low vegetation cover showed higher mortality and dispersal distances than rabbits released in high cover areas. Warren fencing decreased both the dispersal of rabbits and the adverse impact of predation in low cover areas, but had no effect in high cover areas. Selection of high cover areas or warren fencing in low cover areas seem to be the most advantageous release conditions to decrease the short-term predation impact, reducing the biological cost of rabbit translocations and the risks for endangered predators derived from the use of traditional predator control practices during translocations. 相似文献
76.
77.
Marta Crivos María Rosa Martínez María Lelia Pochettino Carolina Remorini Cynthia Saenz Anahí Sy 《Agriculture and Human Values》2004,21(2-3):111-125
Through the ethnographic record of the subsistence activities partially or completely performed in the domestic sphere in two Mbyá-Guaraní settlements in Misiones (Argentina), we outline factors important in describing the local natural environment. Data was collected through systematic observation and also through semi-structured interviews. Analysis indicates that the natural environment of the area is characterized by the indigenous community in several different ways. Thus, local people view the environment as made up of different “micro-environments,” and they consequently think of the elements that compose these “micro-environments” as having different, distinct characteristics. In the context of their daily activities, both these “micro-environments” and the elements that compose them are regarded as resources, in that they are viewed in terms of what is in them relevant to the subsistence of these groups in the rainforest. It is the intention of this study to initiate the systematic recording and processing of information on how these indigenous communities know and manage the natural resources available to them in their daily life. 相似文献
78.
Schiestl FP Peakall R Mant JG Ibarra F Schulz C Franke S Francke W 《Science (New York, N.Y.)》2003,302(5644):437-438
The "sexually deceptive" orchid Chiloglottis trapeziformis attracts males of its pollinator species, the thynnine wasp Neozeleboria cryptoides, by emitting a unique volatile compound, 2-ethyl-5-propylcyclohexan-1,3-dione, which is also produced by female wasps as a male-attracting sex pheromone. 相似文献
79.
R W Schevitz M A Navia D A Bantz G Cornick J J Rosa M D Rosa P B Sigler 《Science (New York, N.Y.)》1972,177(47):429-431
An isomorphous osmium derivative of crystalline yeast initiator transfer RNA has been prepared and interpreted to 6-angstrom resolution. The coordinates of the heavy atoms have been determined by Patterson and "direct" methods applied to the difference coefficients of the centric projections, followed by least-squares refinement. There is one dominant site per asymmetric unit, consistent with the finding by neutron-activation analysis that there is approximately one osmium atom per molecule of transfer RNA. The osmium derivative appears to be a normal substrate for enzymatic aminoacylation. 相似文献
80.
Cimino G DE Rosa S DE Stefano S Sodano G Villani G 《Science (New York, N.Y.)》1983,219(4589):1237-1238
A biosynthetic experiment with mevalonic acid labeled with carbon-14 showed that the nudibranch Dendrodoris limbata elaborates polygodial, a sesquiterpenoid dialdehyde stored in the mantle, which constitutes its chemical defense against predators. Previously described nudibranchs drew defensive chemicals from their preys. 相似文献