Adolescent–Parent Relations in Asian Indian and Salvadoran Immigrant Families: A Cultural–Developmental Analysis of Autonomy,Authority, Conflict,and Cohesion

From a cultural perspective, this study addressed the two developmental theories that adolescents want more autonomy and fewer parental rules than parents consider appropriate, and that discrepancy between adolescents and parents on views of autonomy and authority result in decreased cohesion and increased conflict. The study included 100 adolescent–parent dyads who were immigrants to the United States from El Salvador and India. While findings pointed to cross‐cultural commonalities, such as autonomy seeking among adolescents, they also highlighted the importance of culture to different meanings of autonomy and the limits of the discrepancy thesis. The discussion calls for future scholarship to include concepts of salience to diverse groups such as family interdependence and appreciation for the parental immigrant experience.     

Optimal PPS Sampling with Vanishing Auxiliary Variables – with Applications in Microscopy

Recently, non‐uniform sampling has been suggested in microscopy to increase efficiency. More precisely, proportional to size (PPS) sampling has been introduced, where the probability of sampling a unit in the population is proportional to the value of an auxiliary variable. In the microscopy application, the sampling units are fields of view, and the auxiliary variables are easily observed approximations to the variables of interest. Unfortunately, often some auxiliary variables vanish, that is, are zero‐valued. Consequently, part of the population is inaccessible in PPS sampling. We propose a modification of the design based on a stratification idea, for which an optimal solution can be found, using a model‐assisted approach. The new optimal design also applies to the case where ‘vanish’ refers to missing auxiliary variables and has independent interest in sampling theory. We verify robustness of the new approach by numerical results, and we use real data to illustrate the applicability.     

世界公共交通简讯

<正>意大利意大利首都罗马十分重视城市的生态环境,尤其是拥有众多历史建筑的市中心。为此制定了一个目标,要求在这个范围内行驶的公共交通车辆都要做到"零排放"。该市的Atac SpA交通公司于1996年开始使用Gulliver U500 ESP小型电动公共汽车,1999年开始增加Iveco 12 m混合动力公共汽车,此后又增加了12 m Mercedes Citaro CRT公共     

Misspecified T2 tests. i. location and scale

Properties of Hotelling's (1931) T ² are studied under model misspecification in the model for a multivariate experiment. Stochastic bounds on T ² and further properties of the T ² test are studied under misspecified location and scale. The bounds are evaluated numerically in selected cases.     

Saddlepoint approximations to exact tests and improved likelihood ratio tests for the gamma distribution

For the most common one-sample and two-sample tests in the gamma distribution we derive the log likelihood ratio tests and the improved versions obtained by a Bartlett adjustment. For most of these tests an exact test exists and we give the saddlepoint approximation to the latter. The tests are compared with previously published tests and a small simulation study is included.     

A monte carlo study on two methods of calculating the mle's covariance matrix in a seemingly unrelated nonlinear regression. *

Econometric techniques to estimate output supply systems, factor demand systems and consumer demand systems have often required estimating a nonlinear system of equations that have an additive error structure when written in reduced form. To calculate the ML estimate's covariance matrix of this nonlinear system one can either invert the Hessian of the concentrated log likelihood function, or invert the matrix calculated by pre-multiplying and post multiplying the inverted MLE of the disturbance covariance matrix by the Jacobian of the reduced form model. Malinvaud has shown that the latter of these methods is the actual limiting distribution's covariance matrix, while Barnett has shown that the former is only an approximation.

In this paper, we use a Monte Carlo simulation study to determine how these two covariance matrices differ with respect to the nonlinearity of the model, the number of observations in the dataet, and the residual process. We find that the covariance matrix calculated from the Hessian of the concentrated likelihood function produces Wald statistics that are distributed above those calculated with the other covariance matrix. This difference becomes insignificant as the sample size increases to one-hundred or more observations, suggesting that the asymptotics of the two covariance matrices are quickly reached.     

A simple method for finding a legal configuration in complex Bayesian networks

This paper deals with an important problem with large and complex Bayesian networks. Exact inference in these networks is simply not feasible owing to the huge storage requirements of exact methods. Markov chain Monte Carlo methods, however, are able to deal with these large networks but to do this they require an initial legal configuration to set off the sampler. So far nondeterministic methods such as forward sampling have often been used for this, even though the forward sampler may take an eternity to come up with a legal configuration. In this paper a novel algorithm will be presented that allows a legal configuration in a general Bayesian network to be found in polynomial time in almost all cases. The algorithm will not be proved deterministic but empirical results will demonstrate that this holds in most cases. Also, the algorithm will be justified by its simplicity and ease of implementation.     

Urbanites’ perception of vegetation in landscape-based stormwater management elements (LSM)

Urban Ecosystems - The popularity and use of green infrastructure measures such as green roofs, green walls, and curb extensions is growing, especially in dense urban areas. At the same time, from...