长江荆江分流河的河型及其洪灾防治探讨

从长江荆江分流河的河道平面形态及其近百年来的演变特征、河道比降、河道沉积特征、地质背景和地貌特征等方面进行了论述,认为这些河道是一个统一的网状河流体系。对各主要河道的输水输沙特征及其演变趋势和洪水灾害特征进行了讨论,结合网状河流系的基本特征,提出了洪灾防治的主要措施。     

泥石流体的流变和冲淤特征及其与危险度的关系

从泥石流体流变特性的分析入手,深入地探讨了蒋家沟泥石流阵性流的淤积和冲刷特征。其冲淤变化特征与泥石流体的浓度特性和规模大小的发展过程有很大的关系。根据这些分析,可以将泥石流的危害划分为侵蚀和堆积两大类,并可能进一步完善泥石流危险度的评估。     

山东潍坊紫外线辐射特征及影响因素

近10多年来,随着人类居住环境的恶化,紫外线给人类造成了巨大的伤害。利用潍坊市气象台2004~2006年逐日紫外线观测资料,分析了太阳紫外线辐射到达地面的强度指数和等级,同时分析了这些量的年、月、日变化特征,研究了影响紫外线辐射的主要的几种因子。影响紫外线辐射强度的主要因素是臭氧、地表反射率、大气气溶胶和云,这些影响因素的变化对太阳紫外线到达地面的辐射起着举足轻重的作用。     

煤矿本质安全特征及管理方法研究

分析国内煤矿本质安全管理研究现状及存在问题,进一步讨论煤矿本质安全的内涵。探讨近年来我国煤矿事故发生的致因与根源,指出人的行为安全是我国煤矿本质安全的主要特征。通过研究我国煤矿事故的控制管理,选择事故率作为我国煤矿本质安全判别的参考标准;分析我国煤矿生产的现状与差异,提出了对我国煤矿的本质安全性进行分类判别的思想;从深入开展煤矿安全管理理论研究、加强煤矿安全管理立法、建立煤矿安全管理标准和有效组织机制等方面提出了实现煤矿本质安全的管理策略。     

INCOME DISTRIBUTION IMPACTS OF A WATER DEVELOPMENT PROJECT - BOISE PROJECT,IDAHO, 1950–19701

ABSTRACT: Public investments in water resource development projects are continually under scrutiny in terms of economic, environmental, and social impacts. Results of an analysis of a water development project that supplies irrigation water in Idaho are discussed in terms of the impact on income distribution and income growth 44 to 64 years after the project was initiated. Gini ratios for the rural farm population of these counties were consistently lower than they were for the United States as a whole and for the state of Idaho. In addition, income distributions tended to become more equitable over time in the water project counties. Rural farm population income growth rates were found to be similar to those for the nation as a whole. Some of the reasons for these results may be related to the tendency for income distribution to become more equitable as income increases, and the fact that average farm size is relatively small.     

SEISMIC REFRACTION ANALYSIS OF WATERSHED MANTLE RELATED TO SOIL,GEOLOGY AND HYDROLOGY1

ABSTRACT: An extensive hammer seismic refraction survey was carried out in three contiguous watersheds (217, 89, and 190 acres) on a laccolith near Sturgis, South Dakota to test its utility in rugged mountain terrain. Isopachs (lines connecting points of equal mantle thickness), area-elevation curves (hypsometry), and structure contours were used together with drill cores, petrography, hydrographs, and soil information to interpret the nature and role of porous mantle in the waterflow behavior of the watersheds. Refraction profiles produced only one geologically meaningful seismic contrast within the loccolith. Drill cores indicated a shallow stony profile on a sheeted horizon terminating on isotropic crystalline rock impervious except for tight joints. Means of refraction and core interpretations were not statistically different. Apparent seismic discontinuities deeper within the bedrock lacked geological identity. Storm hydrographs and water yields are better related to soil type differences and porous mantle distribution than to average porous mantle depth. On the other hand, slope of flow-duration curves correlate with average porous mantle depth. Porous mantle isopachs also indicate that measured flow from each basin is total area flow. Thus, porous mantle isopachs and hypsometry, and soil type delineation are complimentary in our interpretation of watershed behavior.     

Use of Approximate Inference in an Index of Completeness of Biological Inventories

Abstract:  To assess the completeness of a floristic or faunal inventory, one may use the ratio of the observed number of species to the "true number" of species ( C ). If the inventory is complete , C = 1. The estimate of the true number can be obtained from accumulation curves, nonparametric methods, or other techniques. We devised a simple method for computing confidence intervals (CI) for C and for evaluating the null hypothesis that the inventory is complete. The method is based on the assumptions that an estimate of the variance of the true number of species is known and that the distribution of the estimator of the true number of species is approximately normal. We applied our method to bird inventories in the Balsas Basin of Mexico. The completeness index for subtransects were lower (84.0, 85.4, and 89.9%) than for the whole transect (91.6%) (all significantly different from 100%). Thus, these particular inventories were incomplete at 2 spatial resolutions. Our method of estimating CI for C can be used to estimate species richness obtained from databases of different sites or to test the null hypothesis that an inventory derived from a database is complete.     

The relationship between diversity profiles,evenness and species richness based on partial ordering

Problems with the notion of evenness, such as ambiguity, proliferation of indices, choice of indices, etc. can be overcome by a more fundamental, mathematical approach. We show that the Lorenz curve is an adequate representation of evenness. The corresponding Lorenz order induces a partial order in the set of equivalent abundance vectors. Also diversity can adequately be studied through a partial order and represented by a curve derived from the classical Lorenz curve. This curve is known as the intrinsic diversity profile (or k-dominance curve) and was introduced by Patil and Taillie (1979) and Lambshead et al. (1981).     

Rethinking receiver operating characteristic analysis applications in ecological niche modeling

The area under the curve (AUC) of the receiver operating characteristic (ROC) has become a dominant tool in evaluating the accuracy of models predicting distributions of species. ROC has the advantage of being threshold-independent, and as such does not require decisions regarding thresholds of what constitutes a prediction of presence versus a prediction of absence. However, we show that, comparing two ROCs, using the AUC systematically undervalues models that do not provide predictions across the entire spectrum of proportional areas in the study area. Current ROC approaches in ecological niche modeling applications are also inappropriate because the two error components are weighted equally. We recommend a modification of ROC that remedies these problems, using partial-area ROC approaches to provide a firmer foundation for evaluation of predictions from ecological niche models. A worked example demonstrates that models that are evaluated favorably by traditional ROC AUCs are not necessarily the best when niche modeling considerations are incorporated into the design of the test.     

武汉市城市化过程中的空气质量响应研究

以武汉市2000-2013年的城市化水平和空气质量状况数据为基础,运用主成分分析法和目标比率模型构建综合评价体系,并用多元回归模型进行检验,探究城市化过程中的空气环境质量响应特征.结果表明:1)2000年以来,武汉城市化进入稳增长的快速抬升阶段,空气污染综合指数总体变化平稳,2013年有变坏的趋势;2)不同类型的污染物对城市化水平具有不同的响应规律和影响程度,SO2为倒“U”型,表明随着城市发展,SO2浓度得到控制并呈下降趋势;NO2为“U”型,近9年来NO2浓度不减反增,对空气环境污染严重;而PM10及空气质量综合水平表现为倒“N”型特征,表明现阶段空间环境呈现污染加重的趋势;3)城市化快速扩张过程中的基础设施建设、建筑扬尘,汽车尾气排放、工业烟尘等是影响武汉空间环境质量的主要因素,需有针对性地加强城市空气环境管理.