Urban flora in the Southeast Europe and its correlation with urbanization

Many studies have refuted the opinion that urban floras are poor in total species number and characterized primarily by neophytes. Also, it has been proved that urban flora differs from its surroundings, and at the same time reflects its richness. Our study focused on urban flora, structure and similarities, and the possible correlation with the urban attributes. Therefore, we selected 11 cities in Southeast Europe, which differ in the development of transportation networks (roads, rails and inland waterways) and population size. Next, we compared two sets of data (structure of urban flora and urban attributes) to define the correlation patterns. Analyzed urban floras were primarily distinguished by a total number of species, number of unique species and neophytes. Belgrade is a city with the highest urbanization level, the most species and the highest number of unique species and neophytes as well. Kosovska Mitrovica, Grocka and Po?arevac stand out by floristic richness. These cities have a high number of species, yet a small proportion of neophytes. Other cities are characterized by similar floristic structure, with a relatively similar proportion of neophytes and approximately similar number of unique species in relation to the total number. It can be concluded that other factors beside the chosen urban attributes have additional effects on floristic structure, except for the factor - the presence of neophytes. This is in accordance with predefining subjects, since urban attributes were chosen based on knowledge about important corridors for invasive species.     

Causes of death contributing to changes in life expectancy in New York City between 1983 and 1992

Recent changes in life expectancy among race and sex groups in New York City were evaluated by analyzing the relative effects of different causes of death in 1983 and 1992, a period in which life expectancy at birth declined by 1.1 years among white males, remained unchanged among black males, and increased 1.2 years among white and black females. Heart disease was found to be the leading cause of death making positive contributions to changes in life expectancy regardless of race or sex, and HIV/AIDS was the leading negative contributor. Overall, deaths from infectious diseases and external causes are becoming more important compared to degenerative conditions in explaining trends in life expectancy in New York City. Past improvements in survival due to reductions in infant deaths are being reversed due to an increase in deaths from preventable causes such as violence and AIDS. Future gains in longevity may require a greater emphasis on policies and programs emphasizing conflict resolution and HIV prevention.     

On location and scale parameters of exponential distributions with censored observations

In this paper we first address the problem of estimating the common scale of several exponential distributions with unknown location parameters when censored samples are observed. The improved estimators are basically Stein type testimators. These testimators are then used to construct improved estimators of location parameters.     

Optimum Mixture Design for the Detection of Synergistic Effects

In mixture experiments, optimal designs for the estimation of parameters, both linear and non-linear, have been discussed by several authors. Optimal designs for the estimation of a subset of parameters have also been investigated. However, designs for testing the effects of certain factors and interactions have been studied only in the context of response surface models. In this article, we attempt to find the optimum design for testing the presence of synergistic effects in a mixture model. The classical F-test has been considered and the optimum design has been obtained so as to maximize the power of the test. It is observed that the barycenters are necessarily the support points of the trace-optimal design.     

Second-order properties of intraclass correlation estimators for a symmetric normal distribution

Consider the problem of estimating the intraclass correlation coefficient of a symmetric normal distribution under the squared error loss function. The general admissibility of the standard estimators of the intraclass correlation coefficient is hard to check due to their complicated sampling distributions. We follow the asymptotic decision-theoretic approach of Ghosh and Sinha (1981) and prove that the three standard intraclass correlation estimators (the maximum-likelihood estimator, the method-of-moments estimator and the first-order unbiased estimator) are second-order admissible for all p ≥ 2, p being the dimension of the distribution.