The Impact of Asynchronicity on Event‐Flow Estimation in Basin‐Scale Hydrologic Model Calibration1

Abstract: The calibration of basin‐scale hydrologic models consists of adjusting parameters such that simulated values closely match observed values. However, due to inevitable inaccuracies in models and model inputs, simulated response hydrographs for multiyear calibrations will not be perfectly synchronized with observed response hydrographs at the daily time step. An analytically derived formula suggests that when timing errors are significant, traditional calibration approaches may generally underestimate the total event‐flow volume. An event‐adaptive time series is developed and incorporated into the Nash‐Sutcliffe Efficiency objective function to diagnose the potential impact of event‐flow synchronization errors. Test sites are the 50 km² Subwatershed I of the Little River Experimental Watershed (LREWswI) in southeastern Georgia, and the 610 km² Little Washita River Experimental Watershed (LWREW) in southwestern Oklahoma, with the Soil and Water Assessment Tool used as the hydrologic model. Results suggest that simulated surface runoff generation is 55% less for LREWswI when the daily time series is used compared with when the event‐adaptive technique is used. Event‐flow generation may also be underestimated for LWREW, but to a lesser extent than it may be for LREWswI, due to a larger portion of the event flow being lateral flow.     

连续曝气SBR快速培养AGS及反应器流态的CFD解析

配制模拟番茄酱废水,在高径比为10的SBR反应器中,考察连续曝气条件下好氧颗粒污泥（AGS）的除污性能和微生物特性的变化。建立流体动力学模型,模拟反应器中气〖CD*2〗液〖CD*2〗污泥三相流的流态,以了解其对污泥颗粒化的影响机理。结果表明：污泥完全颗粒化后,对番茄酱废水中COD、NH3-N和PO3-4-P的去除率分别为94.37%、93.55%和9092%;绿弯菌门(Chloroflexi)、拟杆菌门(Bacteroidetes)和厚壁菌门(Firmicutes)丰度显著提高,假丝酵母菌（Candidatus saccharibacteria）为除磷功能微生物;反应器内的流态结构呈环流和旋涡流,水力剪切力的大小与颗粒粒径呈正相关,颗粒形态与流态分布有关。     

Dynamic modeling of chemical fate and transport in multimedia environments at watershed scale-I: theoretical considerations and model implementation

A geo-referenced environmental fate model was developed for analyzing unsteady-state dispersion and distribution of chemicals in multimedia environmental systems. Chemical transport processes were formulated in seven environmental compartments of air, canopy, surface soil, root-zone soil, vadose-zone soil, surface water, and sediment. The model assumed that the compartments were completely mixed and chemical equilibrium was established instantaneously between the sub-compartments within each compartment. A fugacity approach was utilized to formulate the mechanisms of diffusion, advection, physical interfacial transport, and transformation reactions. The governing equations of chemical mass balances in the environmental compartments were solved simultaneously to reflect the interactions between the compartments. A geographic information system (GIS) database and geospatial analysis were integrated into the chemical transport simulation to provide spatially explicit estimations of model parameters at watershed scale. Temporal variations of the environmental properties and source emissions were also considered in the parameter estimations. The outputs of the model included time-dependent chemical concentrations in each compartment and its sub-compartments, and inter-media mass fluxes between adjacent compartments at daily time steps.     

The implications of ecosystem dynamics for fisheries management: a case study of selected fisheries in the Gulf of Paria, Trinidad

It is accepted that if fisheries resources are to remain renewable and able to sustain livelihoods, appropriate management practices must be implemented. Even while fisheries management grapples to resolve single-species issues, the biological and economic interactions among species mandate that to be effective, management techniques must be based on more interactive and aggregate-level analyses. In order to implement these techniques, the actual links, and the potential impact of these links, among the fisheries must be established. Vector autoregression (VAR) analysis has the potential to play an increasingly important role in ecosystem modelling for fisheries management. This study uses VAR analysis to demonstrate the quantitative impact of certain ecosystem changes on the productivity of the carite, honey shrimp and croaker fisheries of the Gulf of Paria, Trinidad, in the particular context of the ecosystem dynamics of trophic linkages, bycatch and multispecies fisheries. Four VAR models are constructed to investigate the extent to which these factors affect the production of the selected fisheries, and to evaluate the management implications of these linkages. The empirical analysis is further evidence that, if sustainable management of fishery resources is to be achieved, management practices based on more multi-species, ecosystem approaches must replace the traditional, single-species management techniques.     

国家资源安全及其系统分析

资源安全是一个国家或地区可以持续、稳定、及时、足量和经济地获取所需自然资源的状态或能力。影响资源安全的因素主要包括结构、质量、数量、空间、价格、技术、制度等。分析了国家资源安全的主体目标导向性、实现过程可调控性、发展演化的长期性、空间层次差异性和系统内外互动性等特性。构建了包括社会、经济、资源、生态环境、政策法律等子系统在内的国家资源安全的系统分析框架。运用PSR模型，进行了国家资源安全系统动力学分析。     

Long-term population dynamics of ixodid ticks and development of tick-borne encephalitis foci under conditions of the middle taiga subzone

Long-term (1995–2003) population dynamics of ixodid ticks and their main hosts (small mammals) and conditions providing for the formation of tick-borne encephalitis (TBE) foci were studies in the middle taiga subzone (Karelia). The results show that the bank vole (Clethrionomys glareolus Schr.) is the main host for the larvae and nymphs of Ixodes persulcatus Schulze, 1930 and for the larvae, nymphs, and adult individuals of I. trianguliceps Birula, 1895. The proportion of ticks feeding on this species (relative to their total number) reaches 63.3% (64.0% of I. persulcatus and 61.1% of I. trianguliceps). Activity of a TBE focus is determined primarily by the abundance of bank voles of older age groups.     

Review of Recent Ecotoxicological Studies on Cladocerans

Cladocerans have been widely used as the bioassay organisms in evaluating the impact of different toxic substances. Literature survey during the last 10 years revealed that cladoceran ecotoxicological research has been in an exponential phase constituting nearly 10% of publications on this group. Many studies have considered typically planktonic taxa such as Daphnia magna, D. pulex, Moina macrocopa, M. micrura and Ceriodaphania dubia. Experimental data on toxicity tests, to a lesser extent, are also available for littoral-benthic genera such as Simocephalus, Macrothrix and Alona. Most toxicity tests are limited to the derivation of median lethal concentrations of various durations but mostly at 24 or 48 h. Studies related to the evaluation of changes in the life history variables of cladocerans as a result of sublethal exposure to toxic substances are not many, but gaining importance. The common toxic substances used in the cladoceran toxicity tests appear to be heavy metals, pesticides and a few natural toxins such as cyanotoxins. We review here the effect of different toxic substances on cladocerans based on both the field and the laboratory studies from an ecotoxicology point of view. Suggestions for the future cladoceran ecotoxicology are also commented on.     

三峡工程对长江中游地下水动态和土壤潜育的影响

通过对长江中游四湖地区地下水动态观测数据分析得出，长江对沿岸平原地下水影响程度随距离增大而逐渐减弱。用遥感技术和实地调查，确定了潜育化、沼泽化土壤在四湖和沿庭湖地区分布以及潜在威胁面积。并依此分析了三峡工程对土壤潜育化沼泽化的影响。在大量调查和田间试验的基础上，提出了适用于当地的潜育化沼泽化土壤改良利用途径。     

Integrating the Metapopulation and Habitat Paradigms for Understanding Broad-Scale Declines of Species

Abstract:  Caughley (1994) argued that researchers working on threatened populations tended to follow the "small population paradigm" or the "declining population paradigm," and that greater integration of these paradigms was needed. Here I suggest that two related paradigms exist at the broader spatial scale, namely the metapopulation paradigm and habitat paradigm, and that these two paradigms also need to be integrated if we are to provide sound management advice. This integration is not trivial, and I outline five problems that need to be addressed: (1) habitat variables may not measure habitat quality, so site-specific data on vital rates are needed to resolve the effects of habitat quality and metapopulation dynamics; (2) measurements of vital rates may be confounded by movements; (3) vital rates may be density dependent; (4) vital rates may be affected by genotype; and (5) vital rates cannot be measured in unoccupied patches. I reviewed papers published in Conservation Biology from 1994 to 2003 and found 41 studies that analyzed data from 10 or more sites to understand the factors limiting species' distributions. Five of the analyses presented were purely within the metapopulation paradigm, 14 were purely within the habitat paradigm, 17 involved elements of both paradigms, and 7 were theoretically ambiguous (2 papers presented 2 distinct analyses and were counted twice). This suggests that many researchers appreciate the need to integrate the paradigms. Only one study, however, used data on vital rates to resolve the effects of habitat quality and metapopulation dynamics (problem 1), and this study did not address problems 2–5. I conclude that more intensive research incorporating site-specific data on vital rates and movement is needed to complement the numerous analyses of distributional data being produced.     

成都冬季“干”气溶胶等效复折射率变化特征研究

基于成都市2017年12月逐时的"干"气溶胶散射系数和吸收系数观测数据，结合该时段同时次GRIMM180环境颗粒物分析仪的监测资料，利用免疫进化算法一体化反演550nm波长处"干"气溶胶等效复折射率的实部和虚部，并对其冬季变化特征进行了研究，结果表明："干"气溶胶等效复折射率实部和虚部分别为（1.547±0.0552）和（0.0197±0.00604）."干"气溶胶等效复折射率实部和虚部的日变化形态基本一致，主要表现为"单谷型"特征，二者的谷值出现时段位于15：00~18：00.在日时间尺度上而言，"干"气溶胶等效复折射率实部与质量浓度统计上对其散射消光的演化存在协同作用，"干"气溶胶虚部与质量浓度对其吸收消光的演化也存在类似影响."干"气溶胶等效复折射率虚部是单位质量浓度"干"气溶胶吸收消光能力的重要表征.