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251.
Summary The effect of kinship on incompatibility between colonies of the acacia-ant Pseudomyrmex ferruginea was examined. Colonies were reared on a clone of Acacia hindsii in a standard environment. A slight but significant reduction in intercolony incompatibility was obtained within two inbred lineages, compared with the observed frequency of rejection for unrelated colonies. These results indicate that the relevant odor differences between colonies are probably not determined at a single gene locus. The gestalt model for recognition pheromones does not apply to P. ferrugnea, since nestmates are often treated differently upon introduction to a second colony. However, the resulting intermediate rejection frequencies (30–100%) fail to converge on the 50% level predicted by single locus models for recognition pheromones. 相似文献
252.
Heikens A Widianarko B Dewi IC de Boer JL Seinen W van Leeuwen K 《Environmental geochemistry and health》2005,27(5-6):475-483
In Asembagus (East Java, Indonesia), surface water is contaminated with effluent from the hyperacid Ijen Crater Lake. In a
previous study, we reported that food crops irrigated with this water had increased concentrations of various elements. Here,
we present a total diet study for adults and 6-year-old children to determine if the mean daily intake of a broad range of
elements is safe and adequate. For children, the intake of B, Mg, Mn and V is high with Hazard Quotients (HQ) of 1.1 (B),
1.4 (Mn) and 1.4 (V), respectively (no TDI is available for Mg). For Mn, the daily intake is high due to the consumption of
locally produced rice. Drinking water is the main source of B, Mg and V. For adults, the intake of Mg, Mn and V is also high
but HQ values are ≤0.7. For both children and adults, the intake of Ca, Zn and particularly Fe is below the RNI (Fe intake
is 90% below the RNI for women). It is concluded the mean intake of elements is unbalanced and Fe deficiency is probably the
most serious health problem. Toxic effects cannot be fully excluded since deficiency of essential elements such as Ca, Fe
and Zn can increase the absorption and retention of various elements. 相似文献
253.
254.
255.
Alex J. Cannon Paul H. Whitfield 《Journal of the American Water Resources Association》2001,37(1):73-89
ABSTRACT: Transient events in water chemistry in small coastal watersheds, particularly pH depressions, are largely driven by inputs of precipitation. While the response of each watershed depends upon both the nature of the precipitation event and the season of the year, how the response changes over time can provide insight into landscape changes. Neural network models for an urban watershed and a rural‐suburban watershed were developed in an attempt to detect changes in system response resulting from changes in the landscape. Separate models for describing pH depressions for wet season and dry season conditions were developed for a seven year period at each watershed. The neural network models allowed separation of the effects of precipitation variations and changes in watershed response. The ability to detect trends in pH depression magnitudes was improved by analyzing neural network residuals rather than the raw data. Examination of sensitivity plots of the models indicated how the neural networks were affected by different inputs. There were large differences in effects between seasons in the rural‐suburban watershed whereas effects in the urban watershed were consistent between seasons. During the study period, the urban watershed showed no change in pH depression response, while the rural‐suburban watershed showed a significant increase in the magnitude of pH depressions, likely the result of increased urbanization. 相似文献
256.
Fariba Mahmoudkhani Maryam Rezaei Vahid Asili Mahsasadat Atyabi Elena Vaisman Cooper H. Langford Alex De Visscher 《Frontiers of Environmental Science & Engineering》2016,10(6):10
A photochemical model of benzene degradation compares well with experimental data obtained in the Lab.
62 reactions were needed to fully describe benzene degradation.
A feasibility study shows that the photolysis of benzene is a cost-effective process.
Experimental data and modeling results show that the degradation efficiency will increase when the combination of UV light and ozone is used.
The degradation of benzene, a carcinogenic air pollutant, was studied in a gas-phase photochemical reactor with an amalgam lamp emitting ultraviolet light at 185 and 254 nm. Efficient benzene degradation (>70%) was possible for benzene mass flow rates of up to 1.5 mg·min−1. Adding ozone allowed benzene mass flow rates of up to 5 mg·min−1 to be treated with the same efficiency. In terms of energy consumption, ozone doubles the efficiency of the process. A comprehensive mechanistic simulation model was developed incorporating a chemical kinetics model (62 reactions involving 47 chemical species), a material balance model incorporating diffusion and flow, a flow velocity model, and a light field model. The model successfully predicted the efficiency of the reactor, generally within 20%, which indicates that the model is sound, and can be used for feasibility studies. The prediction of the reactor efficiency in the presence of ozone was less successful, with systematically overestimated efficiency. Condensation of reaction products in the reactor is thought to be the main cause of model inaccuracy. Both experimental data and model predictions show that there is a synergistic effect between ozonation and ultraviolet degradation. 相似文献
257.
The dynamics of shifting cultivation captured in an extended Constrained Cellular Automata land use model 总被引:3,自引:0,他引:3
Rohan Chandralal Wickramasuriya Arnold K. Bregt Hedwig van Delden Alex Hagen-Zanker 《Ecological modelling》2009
This paper presents an extension to the Constrained Cellular Automata (CCA) land use model of White et al. [White, R., Engelen, G., Uljee, I., 1997. The use of constrained cellular automata for high-resolution modelling of urban land-use dynamics. Environment and Planning B: Planning and Design 24(3), 323–343] to make it better suited for modelling the dynamics of shifting cultivation. In the extended model the time passed since the last land use transition of a location is a factor of its land use potential. The model can now account for the gradual decrease in soil fertility after an area of forest has been cleared for cultivation and also capture the process of regeneration once the plot is fallowed. The model is applied for the Ruhunupura area of Sri Lanka where chena, a particular practice of shifting cultivation, is a common land use that dominates the landscape dynamics. The model is calibrated for the period 1985–2001 and the results are assessed in terms of location to location overlap as well as structural similarity at multiple scales. These results give confidence in the representation of land use dynamics for the main land use classes. On the basis of a long term scenario run for the period 2001–2030, it is verified that the model captures stylized facts related to chena dynamics, in particular shortening fallow periods and increasingly long cultivation periods of chena, as a result of increasing land use pressure. 相似文献
258.
Alex Córdoba-Aguilar 《Behavioral ecology and sociobiology》2009,63(5):751-763
One unexplored area in sexual conflict studies is the female physiological costs and possible resource reallocation that accompany
evolutionary costs due to male harassment. Using females of the damselfly Hetaerina americana, I first investigated whether male harassment affected female mating rate and survival and explored whether such effects
induced a resource allocation from immunity (in the form of phenoloxidase activity) and muscular fat reserves to egg number
and size. Using two seasons that differed in male harassment, it was found that the higher the male harassment, the fewer
are the female matings and the lower is the female survival. These results were corroborated using an experimental approach
in which a situation of high male harassment was induced. It was also found that when the first mating takes place and at
high male harassment, females had more reduced phenoloxidase activity and fat reserves and tended to lay most of the eggs
they produce in their lifetime and these were considerably large. However, at low male harassment, egg number and size were
more equally produced across matings. Females under high male harassment seemed to suffer the survival costs but may show
a plastic evolutionary response of reallocating resources to egg traits to maximize fitness. 相似文献
259.
Nation‐building policies in Timor‐Leste: disaster risk reduction,including climate change adaptation
Jessica Mercer Ilan Kelman Francisco do Rosario Abilio de Deus de Jesus Lima Augusto da Silva Anna‐Maija Beloff Alex McClean 《Disasters》2014,38(4):690-718
Few studies have explored the relationships between nation‐building, disaster risk reduction and climate change adaptation. Focusing on small island developing states, this paper examines nation‐building in Timor‐Leste, a small island developing state that recently achieved independence. Nation‐building in Timor‐Leste is explored in the context of disaster risk reduction, which necessarily includes climate change adaptation. The study presents a synopsis of Timor‐Leste's history and its nation‐building efforts as well as an overview of the state of knowledge of disaster risk reduction including climate change adaptation. It also offers an analysis of significant gaps and challenges in terms of vertical and horizontal governance, large donor presence, data availability and the integration of disaster risk reduction and climate change adaptation for nation‐building in Timor‐Leste. Relevant and applicable lessons are provided from other small island developing states to assist Timor‐Leste in identifying its own trajectory out of underdevelopment while it builds on existing strengths. 相似文献
260.
Alex Wharton 《生态毒理学报》2004,26(2):76-79
建筑业是最古老、最重要的工业之一.它提供了庇护,并为许多人类活动提供了物质框架和基础.它使我们得以生存、参加社会活动、利用我们的环境一总之,实现我们的潜力.但是,同时它也限制了我们的潜力,因为它限制了企业、革新、生产力和以及通过解决贫困、社会排斥和气候变化维持增长的能力.本文介绍了欧盟建筑部门的主要特点,探讨了与促进可持续建筑有关的一些问题.重点介绍了中小建筑企业的基本需求以及为满足这些需求而正在采取的措施.欧洲和其他大陆的发达国家可能还有许多东西要向发展中国家的发展途径和项目支持系统学习. 相似文献