Tree health mapping with multispectral remote sensing data at UC Davis, California

Tree health is a critical parameter for evaluating urban ecosystem health and sustainability. Traditionally, this parameter has been derived from field surveys. We used multispectral remote sensing data and GIS techniques to determine tree health at the University of California, Davis. The study area (363 ha) contained 8,962 trees of 215 species. Tree health conditions were mapped for each physiognomic type at two scales: pixel and whole tree. At the pixel scale, each tree pixel within the tree crown was classified as either healthy or unhealthy based on vegetation index values. At the whole tree scale, raster based statistical analysis was used to calculate tree health index which is the ratio of healthy pixels to entire tree pixels within the tree crown. The tree was classified as healthy if the index was greater than 70%. Accuracy was checked against a random sample of 1,186 trees. At the whole tree level, 86% of campus trees were classified as healthy with 88% mapping accuracy. At the pixel level, 86% of the campus tree cover was classified as healthy. This tree health evaluation approach allows managers to identify the location of unhealthy trees for further diagnosis and treatment. It can be used to track the spread of disease and monitor seasonal or annual changes in tree health. Also, it provides tree health information that is fundamental to modeling and analysis of the environmental, social, and economic services produced by urban forests.     

Bayesian analysis of outlier problems using divergence measures

A Bayesian approach is presented for detecting influential observations using general divergence measures on the posterior distributions. A sampling-based approach using a Gibbs or Metropolis-within-Gibbs method is used to compute the posterior divergence measures. Four specific measures are proposed, which convey the effects of a single observation or covariate on the posterior. The technique is applied to a generalized linear model with binary response data, an overdispersed model and a nonlinear model. An asymptotic approximation using Laplace method to obtain the posterior divergence is also briefly discussed.     

Who Gets What From Government? Distributional Consequences of Child‐Care Assistance Policies

Given the fragmented structure of child‐care assistance in the United States, it has been difficult to obtain accurate estimates of which families are assisted, through which mechanisms, and at what level. Making use of survey data from New York City, we analyze the distribution of several forms of public child‐care assistance. Results suggest that about 40% of all families with young children receive some form of child‐care assistance. Considering all forms of assistance, the distribution of child‐care help is targeted in both expected and some unexpected ways. Implications of these results are discussed in the context of U.S. child‐care policies governing access and benefit levels.     

The role of family help in the housing decisions of young people

Recent debates about flows of help within the family have indicated considerable diversity according to the type of help (money, services), and ages and gender of those involved, and have shown that values are only a partial guide to the scale of such flows. This paper focuses on a particular occasion for help, young people's housing, and a particular region, South-East England, where one would expect family financial help to be high given the capacity to help of older generations (due to higher average incomes and wealth) and the affordability problems faced by young people. It is shown that contrary to hypothesis only 12% of a sample of young people had received financial help for housing purposes since they had left home, less than found in previous studies with different samples. The amounts involved were less than young people believed their parents could afford. The role of inheritance was also found to be minor. The results from the different studies are explained as due to changes in the housing market, changing values regarding financial help and differences among the samples. Intensive re-interviews with three households from very different backgrounds are used to show the different ways in which family help operates.     

追求新亚洲安全:文化视角中的地区合作

21世纪各个国家特别是亚洲各国进入了发展的新阶段。亚洲在经济发展中实现了建设性的双边伙伴关系。但是亚洲国家形成“与西方传统不同的亚洲国际关系模式”仍然任重道远。作者认为,亚洲共同的文化认同可以发挥重要作用,理应把亚洲国家特别是两个人口最多的国家中国和印度团结起来,全面实现“亚洲共同体”的战略目标。     

Married women's resource position and household food expenditures in Cebu,Philippines

This study analyzes how married women use their access to and control over economic resources to increase household spending on food. Using data from Cebu, Philippines, where child malnutrition is high, this study finds that the more income women earn and control, the more households spend on food. Women's control over their income is particularly important for increasing food expenditures in the poorest households. In richer households, women who earn little of their own income also use spouse income transfers to increase food expenditures. The findings from this study suggest that in a developing country setting, improving women's economic status so that they earn and control more household resources can increase household spending on goods that benefit children.