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To investigate the impact of clinical target volume (CTV) shape and size on CTV to planning target volume (PTV) margin expansion.Using numerical integration methods, margins accounting for random errors and systematic errors were calculated for CTVs of different shapes and sizes. We use k(r-95) and k(s-95) to represent the coefficients, for random errors and systematic errors, respectively, that ensure that every point of the CTV receives ≥95% of the prescribed dose.The part of the margin accounting for random errors depends on CTV shape and size; generally, a convex part of a CTV would have a larger margin than a concave part. However, the part of the margin accounting for systematic errors is independent of CTV shape and size.CTV shape and size should be considered when generating a PTV. For a complex CTV, the margins of the various parts of the CTV are different and related to local forms.

Intergenerational disparity in income and health violates the norm of equal opportunity and deserves the attention of researchers and policy makers. To understand changes in intergenerational disparity, we created the intergenerational mobility index (IMI), which can simultaneously measure changes in income rankings and in health outcomes across two generations. We selected obesity as one health outcome to illustrate the application of IMI due to its severe health and financial consequences for society and the significant changes in the distribution of obesity across income groups. Although obesity has increased in all income groups in the last four decades, higher income groups have tended to have a faster increase in obesity, which has reduced the disparity in obesity across income groups. The strength of our intergenerational approach within families is to control the genetic influence, which is one of the strongest determinants of obesity. The decomposition of the IMI illustrates that it captures changes in obesity distribution (holding constant income rankings between generations) and changes in income rankings (holding constant the obesity distribution across generations), simultaneously. We used the data of the Panel Study of Income Dynamics (PSID), which have been collected since 1967, is the longest longitudinal survey in the U.S. The PSID surveyed respondents' height and weight were recorded in 1986 and from 1999 to 2007. We selected respondents from 1986 as the parental generation and respondents from 2007 as the adult children's generation. To make the adult children's body weight status and income comparable to their parents', we stratified the analysis by gender. For the pairs of fathers and adult sons, we found the intergenerational disparity in overweight, a less severe indicator of excessive fatness, across income was decreasing. This was partially due to the up-swing in the adult children's income status. For the pairs of mothers and adult daughters, we found a similar decrease in socioeconomic disparity in obesity. However, decomposition of the IMI indicated that changes in income distributions between mothers and adult daughters contributed smaller effects than that between fathers and adult sons. Our study has demonstrated that the IMI and its decomposition are useful tools for analyzing intergenerational disparity in income and health. [ABSTRACT FROM AUTHOR]

The U.S. Department of Transportation (DOT) defines a flight as "delayed" if it arrives 15+ minutes late. The DOT "flight counting" delay definition is used to rank airline/airport service quality. An obvious caveat of counting flight delays is that the duration of delay plays no role in the delay count. The purpose of this article is to propose an aggregate delay measure that is sensitive to the distribution of time delayed among passengers. The importance of this work is that our derived delay measure reflects passenger preferences rather than the arbitrary delay cutoff established by the DOT. We model passengers' preference ordering using the criteria that passengers prefer fewer, shorter, and more equal delay times. [ABSTRACT FROM AUTHOR]

Rising incomes in China have not led to a smaller degree of undernutrition as measured by percentage of population below calorie and protein recommended daily allowances. The weak relationship between income and nutrition is further demonstrated by our income elasticity estimates for calories and protein, which are generally zero. We do find that the percentage of fat in the calorie source is a normal good. [ABSTRACT FROM AUTHOR]

The article focuses aims to derive the variance-covariance formulae for testing Lorenz and generalized Lorenz curves when samples are not simple random. Specifically, it considers the three most commonly used non-simple random sampling methods: stratified sampling, cluster sampling, and multistage sampling. Consistent and asymptotically unbiased sample estimators of the Lorenz and generalized Lorenz curves come directly from the definitions of the sampling procedures. Using the Bahadur representation, we are able to derive the asymptotic covariance structures of the Lorenz and generalized Lorenz curve estimates. Comparing these structures with those for simple random samples reveals that different sampling methods will lead to quite different variance-covariance formulae. Whether a given sample is treated as simple random or not may greatly affect inference testing; it is thus important to use the correct variance-covariance formulae in performing inference tests. Simple random sampling has been assumed in most statistical inference procedures developed to test Lorenz dominance, concentration dominance, and stochastic dominance. This assumption is highly unrealistic since simple random economic samples are rarely available. As this note has shown, different assumptions about the sampling method may lead to different estimation procedures and different variance-covariance formulae.

Poverty in the United States varies greatly by location. The difference in poverty intensity among locations, however, has only been evaluated by the official poverty measure - the headcount ratio - which has several drawbacks. The official poverty statistics also suffer from use of a single, arbitrary poverty line. This paper uses a recently-developed distribution-sensitive measure of poverty and 1990 census data to reconsider the difference among central city, suburban, and nonmetropolitan poverty levels, as well as differences among US regions. Instead of using a single, arguable poverty line, this paper lets the poverty line vary over an income range so that conclusions are more robust. We check for significance of differences across locations by applying some recently-developed methods of statistical inference. [ABSTRACT FROM AUTHOR]

This paper develops and applies new measures of poverty that overcome a number of specific methodological flaws in the official US poverty statistics. Sen's distribution sensitive index of poverty and each of its components are estimated at several distinct poverty thresholds for the period 1961-1996. Distribution sensitive measures of urban poverty are corrected for interarea differences in the cost of living and for comprehensive incomes. Recently developed statistical inference procedures are applied. Official poverty statistics are shown to be seriously misleading in some time periods and the choice of a poverty line affects conclusions concerning changes in poverty. [ABSTRACT FROM AUTHOR]

This paper comments on the work of Rector et al. (1999a, 1999b). The poverty lines implicit in their restrictive material deprivation approach are disputed and the claim that America has triumphed over poverty is rejected. Evidence is presented showing that poverty among the poorest Americans has significantly increased and is now near an all time high. The long economic expansion since the recession of 1990-1991 has left hardcore poverty essentially unchanged and relative deprivation among the poorest of the poor has increased. [ABSTRACT FROM AUTHOR]

Provides distribution-free inferences for testing marginal rank dominance and Lorenz, and generalized Lorenz dominances. Relationships holding between an income distribution and its dependent after-event distribution; Asymptomatic normal distributions of sample marginal changes; Re-evaluation of marginal impacts of working wives of the United States family income distribution.

This article focuses on the relative and absolute nature of poverty index. Previous poverty research has made use of axioms to construct and evaluate distribution-sensitive poverty measures. An index is distribution sensitive if it satisfies a weak transfer axiom. Poverty decreases when income is transferred from a high-income poor person to low income person. A distribution-sensitive measure is appealing because it reflects the extent of deprivation among the poor and incorporates aspects of poverty that are ignored by standard measures such as headcount ratio and poverty gap ratio. This paper concentrates on the implications of the joint effects of scale and translation invariance.

This article provides a clarification on the extensive literature of aggregate poverty measures. Poverty is in the news every year, especially when the U.S. Bureau of the Census releases the poverty statistics for the previous year. It examine the desirability of each axiom, properties of each poverty measure and interrelationships among axioms. The desirability of an axiom cannot be evaluated in isolation and some combination of axioms may make it impossible to devise a satisfactory poverty measure, some axioms can be implied by other axioms combined and so are not independent, some others are ad hoc and are disqualified as axioms for poverty measurement.

An abstract of the article "The Effects of Race, Income, Mobility and Political Beliefs on Support for Redistribution," by Steven R. Beckman and Buhong Zheng is presented.