Regression analysis of forest damage by marginal models for correlated ordinal responses

Studies on forest damage generally cannot be carried out by common regression models, for two main reasons: Firstly, the response variable, damage state of trees, is usually observed in ordered categories. Secondly, responses are often correlated, either serially, as in a longitudinal study, or spatially, as in the application of this paper, where neighbourhood interactions exist between damage states of spruces determined from aerial pictures. Thus so-called marginal regression models for ordinal responses, taking into account dependence among observations, are appropriate for correct inference. To this end we extend the binary models of Liang and Zeger (1986) and develop an ordinal GEEI model, based on parametrizing association by global cross-ratios. The methods are applied to data from a survey conducted in Southern Germany. Due to the survey design, responses must be assumed to be spatially correlated. The results show that the proposed ordinal marginal regression models provide appropriate tools for analysing the influence of covariates, that characterize the stand, on the damage state of spruce.     

ECO-ENGINEERING-THE CHALLENGE OF RESOURCE DEVELOPMENT1

It is presumed that the present environmental thrust is not a wholly transitory fad; that there will be a residual impact on American society which will demand greater consideration in the future of ecological and environmental values by resource developers and public works agencies. An example is cited to show the validity of the environmental thrust and the severe consequences of ignoring it under the present emphasis on this aspect of resource development. An attempt is made to understand some of the reasons for the dramatic change in public attitude toward the environment and opposition to projects of apparent benefit to society. It is suggested that basic changes in philosophy and concept will be necessary in the field of resource development. Some broad ecological and developmental guidelines are provided in the interest of implementing environmental considerations. Finally, those involved in resource development and public works are challenged to accept the concept of eco-engineering; a concept combining the competing elements of resource development and conservation.     

大气颗粒态有机硝酸酯的转化机制、测量技术及应用

大气中的颗粒态有机硝酸酯是连接挥发性有机物(VOCs)、氮氧化物(NOx)、二次有机气溶胶(SOA)及臭氧的关键物质,总结了近10年国内外对颗粒态有机硝酸酯来源、形成机制、测量分析方法、浓度水平等方面的研究,描述了现有大气化学框架下有机硝酸酯的大气转化机制,梳理了测量有机硝酸酯的离线、在线方法及其优缺点,总结了应用不同...