Trends in inequality in infant mortality in the north of England, 1921–1973, and their association with urban and social structure

Summary.  The paper analyses a time series of infant mortality rates in the north of England from 1921 to the early 1970s at a spatial scale that is more disaggregated than in previous studies of infant mortality trends in this period. The paper describes regression methods to obtain mortality gradients over socioeconomic indicators from the censuses of 1931, 1951, 1961 and 1971 and to assess whether there is any evidence for widening spatial inequalities in infant mortality outcomes against a background of an overall reduction in the infant mortality rate. Changes in the degree of inequality are also formally assessed by inequality measures such as the Gini and Theil indices, for which sampling densities are obtained and significant changes assessed. The analysis concerns a relatively infrequent outcome (especially towards the end of the period that is considered) and a high proportion of districts with small populations, so necessitating the use of appropriate methods for deriving indices of inequality and for regression modelling.     

Statistical inference on asymptotic properties of two estimators for the partially linear single-index models

The outer product of gradients (OPG) estimation procedure based on least squares (LS) approach has been presented by Xia et al. [An adaptive estimation of dimension reduction space. J Roy Statist Soc Ser B. 2002;64:363–410] to estimate the single-index parameter in partially linear single-index models (PLSIM). However, its asymptotic property has not been established yet and the efficiency of LS-based method can be significantly affected by outliers and heavy-tailed distributions. In this paper, we firstly derive the asymptotic property of OPG estimator developed by Xia et al. [An adaptive estimation of dimension reduction space. J Roy Statist Soc Ser B. 2002;64:363–410] in theory, and a novel robust estimation procedure combining the ideas of OPG and local rank (LR) inference is further developed for PLSIM along with its theoretical property. Then, we theoretically derive the asymptotic relative efficiency (ARE) of the proposed LR-based procedure with respect to LS-based method, which is shown to possess an expression that is closely related to that of the signed-rank Wilcoxon test in comparison with the t-test. Moreover, we demonstrate that the new proposed estimator has a great efficiency gain across a wide spectrum of non-normal error distributions and almost not lose any efficiency for the normal error. Even in the worst case scenarios, the ARE owns a lower bound equalling to 0.864 for estimating the single-index parameter and a lower bound being 0.8896 for estimating the nonparametric function respectively, versus the LS-based estimators. Finally, some Monte Carlo simulations and a real data analysis are conducted to illustrate the finite sample performance of the estimators.     

A penalized likelihood approach to image warping

A warping is a function that deforms images by mapping between image domains. The choice of function is formulated statistically as maximum penalized likelihood, where the likelihood measures the similarity between images after warping and the penalty is a measure of distortion of a warping. The paper addresses two issues simultaneously, of how to choose the warping function and how to assess the alignment. A new, Fourier–von Mises image model is identified, with phase differences between Fourier-transformed images having von Mises distributions. Also, new, null set distortion criteria are proposed, with each criterion uniquely minimized by a particular set of polynomial functions. A conjugate gradient algorithm is used to estimate the warping function, which is numerically approximated by a piecewise bilinear function. The method is motivated by, and used to solve, three applied problems: to register a remotely sensed image with a map, to align microscope images obtained by using different optics and to discriminate between species of fish from photographic images.     

湖南县域经济发展梯度分布研究

湖南县域经济发展不均衡,为了研究县域经济发展梯度水平的差异状况,为进一步深入研究湖南县域经济发展提供依据,通过选取经济发展水平、经济发展效益、经济发展速度、县域产业结构等方面若干指标,运用数量经济分析方法进行了实证研究,得出的基本结论是湖南县域经济呈现四个不同的发展梯度。     

Gradients in Depressive Symptoms by Socioeconomic Position Among Men Who Have Sex With Men in the EXPLORE Study

ABSTRACT

This study examines gradients in depressive symptoms by socioeconomic position (SEP; i.e., income, education, employment) in a sample of men who have sex with men (MSM). Data were used from EXPLORE, a randomized, controlled behavioral HIV prevention trial for HIV-uninfected MSM in six U.S. cities (n = 4,277). Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression scale (short form). Multiple linear regressions were fitted with interaction terms to assess additive and multiplicative relationships between SEP and depressive symptoms. Depressive symptoms were more prevalent among MSM with lower income, lower educational attainment, and those in the unemployed/other employment category. Income, education, and employment made significant contributions in additive models after adjustment. The employment-income interaction was statistically significant, indicating a multiplicative effect. This study revealed gradients in depressive symptoms across SEP of MSM, pointing to income and employment status and, to a lesser extent, education as key factors for understanding heterogeneity of depressive symptoms.     

社会分层与健康不平等的性别差异:基于生命历程的纵向分析

本研究考察在社会分层与性别分层的交互作用下,生命历程中的两个竞争性理论--“累积优势/劣势理论”和“年龄中和效应理论”,哪一个更能解释中国男性和女性所经历的健康不平等。本研究利用“中国健康与营养调查”（CHNS）追踪数据和成长曲线模型发现,性别对社会分层导致的健康不平等及其发展有独特的影响。与男性相比,女性在各个年龄阶段都处于健康劣势,这一劣势是因为女性从教育和收入所获得的健康回报比男性低。此外,女性之间因为教育和收入导致的健康不平等程度随年龄的增长而缩小,男性之间的健康不平等程度并不随年龄的增长而改变,因此,本研究不支持健康不平等的“累积优势/劣势假说”,而是在女性群体中支持“年龄中和效应理论”。     

Age and social gradients in the intensity of aging males' symptoms in Poland

Background. We performed the study in order to describe the age-related changes and social gradients in the intensity of aging males' symptoms in healthy men in Poland.

Methods. We examined 405 men aged 32–79, healthy inhabitants of Poland. Severity of aging males' symptoms was assessed using the Polish version of AMS scale. The social position was expressed using their educational level, commonly accepted as a reliable and specific index of social status in Poland.

Results. Male aging in Poland was accompanied by an increase in the intensity of all groups of evaluated symptoms (psychological, sexual and somato-vegetative symptoms, respectively: r = 0.36, r = 0.72, r = 0.59, all p < 0.0001). The results of ANOVA revealed the independent effects of both age and social status on the intensity of psychological symptoms (F = 17.89, p < 0.0001 and F = 9.51, p < 0.0001 for age and educational level, respectively), sexual (F = 114.70, p < 0.0001 and F = 5.90, p < 0.01), and somato-vegetative symptoms (F = 52.86, p < 0.0001 and F = 3.85, p < 0.05). The better the education of Polish men, the less intense the aging males' symptoms, irrespective of their age.

Conclusions. Age and social position constitute major determinants of the intensity of aging males' symptoms in Poland.     

Ecosystem processes along an urban-to-rural gradient

In order to understand the effect of urban development on the functioning of forest ecosystems, during the past decade we have been studying red oak stands located on similar soil along an urban-rural gradient running from New York City ro rural Litchfield County, Connecticut. This paper summarizes the results of this work. Field measurements, controlled laboratory experiments, and reciprocal transplants documented soil pollution, soil hydrophobicity, litter decomposition rates, total soil carbon, potential nitrogen mineralization, nitrification, fungal biomass, and earthworm populations in forests along the 140 × 20 km study transect. The results revealed a complex urban-rural environmental gradient. The urban forests exhibit unique ecosystem structure and function in relation to the suburban and rural forest stands these are likely linked to stresses of the urban environment such as air pollution, which has also resulted in elevated levels of heavy metals in the soil, the positive effects of the heat island phenomenon, and the presence of earthworms. The data suggest a working model to guide mechanistic work on the ecology of forests along urban-to-rural gradients, and for comparison of different metropolitan areas.     

Understory plant species composition in remnant stands along an urban-to-rural land-use gradient

We examined the understory species composition of 24 remnant forest stands along an urban-to-rural gradient in the metropolitan Milwaukee, Wisconsin region to determine the relationships between plant community composition, human disturbance, and contrasting types of land use along a gradient of urbanization. A significant difference was found in shrub species community composition among three contrasting land-use categories but no significant difference was found in herbaceous community composition. Significant differences in human activity existed among rural, urban, and urbanizing land-use categories, but this index of disturbance was not significantly correlated to gradients in species composition. All stands in this study had been subjected to various types of human activity and environmental disturbances in the past. Our data suggest that differences in the relative importance of understory species exist among stands but these differences may not be caused by the impacts of urbanization alone. Changes in the natural disturbance regime of this landscape, along with the impacts associated with urbanization, have led to an individualistic response in the compositional dynamics of forest stands. This revised version was published online in July 2006 with corrections to the Cover Date.