大熊猫主食竹种秆龄鉴定及种群动态评估

四川西南部和西北部中山、亚高山森森下，竹源丰富，其中：拐棍竹和冷箭竹是大熊猫的主食竹种，作者１９８２－１９８７年进行竹类生态研究；通过固定样方观察和带标志茎秆记录分析，发现竹杆和笋箨的颜色，以及主枝叶鞘与枝节数的变化和竹子秆龄的增长密切相关，可以作为鉴定竹秆年龄的依据。根据竹子的秆龄结构，应用负指数函数模型，可以估算竹子种群的增长量和死亡率，评估竹子的种群动态变化，可为主管部门制定保护大熊猫规划规     

SOME HYDROLOGIC IMPACTS OF PLOWING RANGELAND SOILS1

ABSTRACT: Rainfall simulator studies were conducted during 1982 and 1983 on agricultural and native rangeland soils of the same soil series in northern Utah. Results indicate that the same soil series mapped at different locations on agricultural land will have similar 10, 20, and 30 minute infiltration rates and similar interrill erosion rates. Seasonal differences in infiltration and erosion rates were significant. Comparisons between agricultural and native soils were complicated by three-way statistical interactions. Seasonal variations in both infiltration rates and erosion rates were greatest on agricultural soils. Of four soil series on native rangeland, only one showed significant seasonal variation in infiltration rates, while erosion rates were similar across all seasons for all soil series. Soil and cover factors important in predicting infiltration and erosion were identified.     

Nodes,networks, and MUMs: Preserving diversity at all scales

The present focus of practical conservation efforts is limited in scope. This narrowness results in an inability to evaluate and manage phenomena that operate at large spatiotemporal scales. Whereas real ecological phenomena function in a space-time mosaic across a full hierarchy of biological entities and processes, current conservation strategies address a limited spectrum of this complexity. Conservation typically is static (time-limited), concentrates on the habitat content rather than the landscape context of protected areas, evaluates relatively homogeneous communities instead of heterogeneous landscapes, and directs attention to particular species populations and/or the aggregate statistic of species diversity. Insufficient attention has been given to broad ecological patterns and processes and to the conservation of species in natural relative abundance patterns (native diversity).The authors present a conceptual scheme that evaluates not only habitat content within protected areas, but also the landscape context in which each preserve exists. Nodes of concentrated ecological value exist in each landscape at all levels in the biological hierarchy. Integration of these high-quality nodes into a functional network is possible through the establishment of a system of interconnected multiple-use modules (MUMs). The MUM network protects and buffers important ecological entities and phenomena, while encouraging movement of individuals, species, nutrients, energy, and even habitat patches across space and time. An example is presented for the southeastern USA (south Georgia-north Florida), that uses riparian and coastal corridors to interconnect existing protected areas. This scheme will facilitate reintroduction and preservation of wide-ranging species such as the Florida panther, and help reconcile species-level and ecosystem-level conservation approaches.     

PERIODIC AUTOREGRESSIVE-MOVING AVERAGE (PARMA) MODELING WITH APPLICATIONS TO WATER RESOURCES1

Results involving correlation properties and parameter estimation for autoregressive-moving average models with periodic parameters are presented. A multivariate representation of the PARMA model is used to derive parameter space restrictions and difference equations for the periodic autocorrelations. Close approximation to the likelihood function for Gaussian PARMA processes results in efficient maximum-likelihood estimation procedures. Terms in the Fourier expansion of the parameters are sequentially included, and a selection criterion is given for determining the optimal number of harmonics to be included. Application of the techniques is demonstrated through analysis of a monthly streamflow time series.     

SEASONAL PUMPING VARIATION EFFECTS ON WELLHEAD PROTECTION AREA DELINEATION1

ABSTRACT: Delineation of a welihead protection area (WHPA) is the key element in welihead protection programs for drinking water supplies. WHPAs are often delineated under idealized conditions using simple steady-state assumptions, which lead to an incorrect estimation of area and geometry. In this paper, we compare the results from a simple steady-state procedure commonly employed in WHPA delineation with a more complex transient approach that allows consideration of seasonal variation in pumping rates. We also introduce a transient procedure to delineate time-related capture zones using a numerical ground water flow and transport model. Welihead delineation is examined for two municipal wells in Tipton, Oklahoma, using a ten-year time-of-travel criterion. In the steady-state procedure, where we assumed constant pumping rates, we used GPTRAC, a semi-analytical model, and MOC, a numerical model. The capture zone delineated by GPTRAC is comparable in shape with the capture zone delineated by MOC but not in size due to the differences in solution schemes. In the transient procedure, we used MOC and considered the seasonal variation in pumping rates. The capture zones delineated in this procedure were larger than the capture zones delineated by the steady-state procedure using the same model. Further analysis showed that a higher drawdown was predicted in the transient procedure than in the steady-state procedure, which is the reason for larger capture zones.     

Response of Georges Bank cod to periodic and nonperiodic oil spill events

In the management of conflicting dual-resource systems such as continental shelf hydrocarbon extraction and commercial fishing operations, it is necessary to consider the possibility of repeated impact events. The potential magnitude of impacts on Georges Bank fisheries of single oil spill events has been addressed in detail elsewhere (Reed and Spaulding 1979, Reed and others 1980, Spaulding and others 1982). An oil spill-fishery impact estimation model, implemented for the Georges Bank cod fishery (Reed and others 1980), has been used to investigate the potential for nonlinear biological responses to periodic and nonperiodic repetitive spill events. Prerecruit mortality equations incorporating young-of-the-year as well as adult-juvenile interactions, perform acceptably vis-à-vis the historical catch record, but show highly variable behavior under recruitment reductions induced by periodic simulated spills. The results demonstrate the importance of selecting mathematical representations of biological and physical processes underlying population dynamics such that characteristic system behavior is adequately represented in both the time and frequency domains.     

TREND ASSESSMENT OF WATER QUALITY TIME SERIES1

ABSTRACT A general methodology is described for identifying and statistically modeling trends which may be contained in a water quality time series. A range of useful exploratory data analysis tools are suggested for discovering important patterns and statistical characteristics of the data such as trends caused by external interventions. To estimate the entries in an evenly spaced time series when data are available at irregular time intervals, a new procedure based upon seasonal adjustment is described. Intervention analysis is employed at the confirmatory data analysis stage to rigorously model changes in the mean levels of a series which are identified using exploratory data analysis techniques. Furthermore, intervention analysis can be utilized for estimating missing observations when they are not too numerous. The effects of cutting down a forest upon various water quality variables and also the consequences of acid rain upon the alkalinity in a stream provide illustrative applications which demonstrate the effectiveness of the methodology.     

黄姜废水厌氧处理动力学模型试验研究

介绍了厌氧反应动力学的主要模式，对厌氧处理黄姜废水的动力学模型进行了探讨，并求出了黄姜废水的厌氧反应动力学模型和动力学参数max和Ks，为黄姜废水的厌氧处理提供了理论依据。     

基于系统动力学的推进酒精企业清洁生产政策模拟

政府补贴、资源与能源价格、排污收费等政策是影响企业实施清洁生产的重要因素。本文以某酒精企业推进清洁生产的系统动力学模型为例模拟政府的政策对于企业开展清洁生产的收益的影响，为决策者调节其政策提供科学依据。     

生物絮凝吸附有机物降解动力学模型研究

生物絮凝吸附强化一级处理对于解决中小城镇污水处理问题有较大意义,在生物絮凝吸附后串联生物接触氧化法构成强化生物絮凝＋生物接触氧化一体化工艺,利用高负荷段的生物絮凝吸附强化一级处理提高SS、COD的去除率来降低后续生物膜的处理负荷,从而形成一种高效、低耗的新型处理工艺。探讨了生物絮凝吸附段的有机物降解动力学模型,并对模型进行了检验。