999 resultados para Seasonal semideciduous forest
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Tooth wear in primates is caused by aging and ecological factors. However, comparative data that would allow us to delineate the contribution of each of these factors are lacking. Here, we contrast age-dependent molar tooth wear by scoring percent of dentine exposure (PDE) in two wild African primate populations from Gabonese forest and Kenyan savanna habitats. We found that forest-dwelling mandrills exhibited significantly higher PDE with age than savanna yellow baboons. Mandrills mainly feed on large tough food items, such as hard-shell fruits, and inhabit an ecosystem with a high presence of mineral quartz. By contrast, baboons consume large amounts of exogenous grit that adheres to underground storage organs but the proportion of quartz in the soils where baboons live is low. Our results support the hypothesis that not only age but also physical food properties and soil composition, particularly quartz richness, are factors that significantly impact tooth wear. We further propose that the accelerated dental wear in mandrills resulting in flatter molars with old age may represent an adaptation to process hard food items present in their environment.
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Postprint (published version)
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The causal mechanism and seasonal evolution of the internal wave field in a deep, warm, monomictic reservoirare examined through the analysis of field observations and numerical techniques. The study period extends fromthe onset of thermal stratification in the spring until midsummer in 2005. During this time, wind forcing wasperiodic, with a period of 24 h (typical of land–sea breezes), and the thermal structure in the lake wascharacterized by the presence of a shallow surface layer overlying a thick metalimnion, typical of small to mediumsized reservoirs with deep outtakes. Basin-scale internal seiches of high vertical mode (ranging from mode V3 toV5) were observed in the metalimnion. The structure of the dominant modes of oscillation changed asstratification evolved on seasonal timescales, but in all cases, their periods were close to that of the local windforcing (i.e., 24 h), suggesting a resonant response. Nonresonant oscillatory modes of type V1 and V2 becamedominant after large frontal events, which disrupted the diurnal periodicity of the wind forcing
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The Kyoto protocol allows Annex I countries to deduct carbon sequestered by land use, land-use change and forestry from their national carbon emissions. Thornley and Cannell (2000) demonstrated that the objectives of maximizing timber and carbon sequestration are not complementary. Based on this finding, this paper determines the optimal selective management regime taking into account the underlying biophysical and economic processes. The results show that the net benefits of carbon storage only compensate the decrease in net benefits of timber production once the carbon price has exceeded a certain threshold value. The sequestration costs are significantly lower than previous estimates
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Traditionally, fossil fuels have always been the major sources of the modern energy production. However prices on these energy sources have been constantly increasing. The utilization of local biomass resources for energy production can substitute significant part of the required energy demand in different energy sectors. The introduction of the biomass usage can easily be started in the forest industry first as it possesses biomass in a large volume. The forest industry energy sector has the highest potential for the fast bioenergy development in the North-West Russia. Therefore, the question concerning rational and effective forest resources use is important today as well as the utilization of the forestry by-products. This work describes and analyzes the opportunities of utilising biomass, mainly, in the form of the wood by-products, for energy production processes in general, as well as for the northwest Russian forest industry conditions. The study also covers basic forest industry processes and technologies, so, the reader can get familiar with the information about the specific character of the biomass utilization. The work gives a comprehensive view on the northwest forest industry situation from the biomass utilisation point of view. By presenting existing large-scale sawmills and pulp and paper mills the work provides information for the evaluation of the future development of CHP investments in the northwest Russian forest industry.