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Rui Sérgio S. Murrieta Darna L. Dufour Andrea D. Siqueira 《Human ecology: an interdisciplinary journal》1999,27(3):455-475
In this article data on household food consumption is used to further understanding of subsistence strategies in three Caboclo populations on Marajó Island, Amazonia, Brazil. Data were collected using participant observation and 24-hour food recalls in 16 households for 7 consecutive days during the rainy (March) and dry (July) seasons. Marajó-Açu households (n = 6) had the highest levels of energy and protein intake relative to recommendations. This was probably related to their successful integration into the prosperous acai (a palm fruit) market of the riverine area. Praia Grande households (n = 6) had the lowest values for energy intake (rainy season), which supports the authors' ethnographic observations of some instability in the subsistence system of this population. Paricatuba households (n = 4) exhibited intermediate values of energy and protein intakes, but less seasonal variation in consumption than the other two populations. Despite the differences observed, food consumption does not appear to be a major limitation for any of the three populations. The data support recent hypotheses concerning the concomitant and multiple use of várzea (floodplain) and terra firme (upland) environments by the Caboclos and integration into the local market economy as the central strategies in dealing with the so-called socioenvironmental constraints of the Amazonian floodplain. 相似文献
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《African Journal of Aquatic Science》2013,38(2):305-311
The median lethal copper (Cu) concentration (96 hr-LC50) values for acute Cu toxicity for Tilapia sparrmanii (live mass: 30 ± 8g) in Mooi River hard water of dolomitic origin at 20 °C, pH 7.9, was 68.1 μmol l?1. At this 96 hr-LC50 value the specific oxygen consumption rate (∈ O2) decreased by 44.2 (± 2.1) % from a non-exposed value of 6.6 (±0.32) mmol O2 kg?1 hr?1 to 3.63 (±0.23) mmol O2 kg ?1 hr?1. At 46.4 μmol Cu l?1, 100% of the exposed T. sparrmanii were still alive after 96 hours, but the ∈ O2 decreased by a mean value of 1.65 (± 0.16) mmol O2 kg?1 fish hr?1 or 25% (± 2.4). Contrary to Pb and Cd, Cu as CuCl2 2H2O was not precipitated in hard water four days after it was dissolved. Thus T. sparrmanii and other cichlids are shown to be more than an order of magnitude more resistant to Cu as a toxicant than most salmonids. 相似文献
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