Bivariate symbolic regression models for interval-valued variables

Interval-valued variables have become very common in data analysis. Up until now, symbolic regression mostly approaches this type of data from an optimization point of view, considering neither the probabilistic aspects of the models nor the nonlinear relationships between the interval response and the interval predictors. In this article, we formulate interval-valued variables as bivariate random vectors and introduce the bivariate symbolic regression model based on the generalized linear models theory which provides much-needed exibility in practice. Important inferential aspects are investigated. Applications to synthetic and real data illustrate the usefulness of the proposed approach.     

Spanish migrants to European Union countries: predictors of psychological adjustment / Españoles que emigran a países de la Unión Europea: predictores de su ajuste psicológico

In recent years, the migration of Spanish people to other countries in Europe has increased; however, there are hardly any studies on this phenomenon. The aim of this study is to identify the predictive sociodemographic and psychosocial factors of psychological adjustment (life satisfaction and absence of internalizing symptoms) of emigrants and to determine the indirect effects of these factors through perceived stress. This study also seeks to examine whether the psychological adjustment of Spanish emigrants was similar to Spanish non-emigrants. The sample was made up of a group of Spanish emigrants to Germany and England (n = 858) and an equivalent control group of Spanish non-emigrants (n = 328). The results show that fulfilment of expectations, emotional support and job quality are the best predictors of perceived stress and psychological adjustment. These factors are confirmed to have indirect effects on psychological adjustment through perceived stress. Finally, the mental health of emigrants and non-emigrants was similar, and the implications of these findings are discussed.     

Role of Temperament,Parenting Behaviors,and Stress on Turkish Preschoolers’ Internalizing Symptoms

Child‐ and family‐related factors that predict internalizing symptoms are understudied in preschool years and have a negative influence on children's functioning. We examined observational assessments of preschoolers' temperamental fearfulness and exuberance, mother reports of negative control, warmth, and parenting stress in a sample of 109 Turkish preschoolers. High temperamental fearfulness and low joyful/exuberant positive affectivity in addition to low warmth and high parenting stress had significant effects on internalizing symptoms. Parenting stress had both direct and indirect relations to internalizing symptoms via lower maternal warmth. When comorbid elevations in externalizing symptoms were controlled, the results were consistent with the interpretation that poor parenting practices and stress associated with the parenting role predict maladaptation in general but that the specific form of maladaptation may be best predicted by individual differences in children's temperamental characteristics. This study contributes to our understanding of risk and protective factors that predict preschoolers' internalizing symptoms with a sample from a non‐Western population. These findings can guide early prevention and intervention programs to address internalizing problems in a culturally‐sensitive way.     

A note on the mean residual life of a coherent system with a cold standby component

In this paper, we investigate the effect of a cold standby component on the mean residual life (MRL) of a system. When the system fails, a cold standby component is immediately put in operation. We particularly focus on the coherent systems in which, after putting the standby component into operation, the failure of the system is due to the next component failure. For these systems, we define MRL functions and obtain their explicit expressions. Also some stochastic ordering results are provided. Such systems include k-out-of-n systems. Hence, our results extend some results in literature.     

Effect of tuberculosis on immune restoration among HIV-infected patients receiving antiretroviral therapy

In this article, time to immune recovery during antiretroviral therapy was estimated and compared between HIV-infected children with and without tuberculosis (TB). CD4?T-cell restoration was used as a criterion for determining immune recovery. The median residual lifetime function, which is more intuitive and robust compared to the frequently used measures of lifetime data, was used to estimate time to CD4?T-cell restoration. The median residual lifetime is not influenced by extreme observations and heavy-tailed distributions which are commonly encountered in clinical studies. Permutation-based methods were used to compare the CD4?T-cell restoration times between the two groups of patients. Our results indicate that children with TB had uniformly higher median residual lifetimes to immune recovery compared to those without TB. Although TB was associated with slower CD4?T-cell restoration, the differences between the restoration times of the two groups were not statistically significant.     

The beta generalized linear exponential distribution

In this paper, a new five-parameter lifetime distribution called beta generalized linear exponential distribution (BGLED) is introduced. It includes at least 17 popular sub-models as special cases such as the beta linear exponential, the beta generalized exponential, and the exponentiated generalized linear distributions. Mathematical and statistical properties of the proposed distribution are discussed in details. In particular, explicit expression for the density function, moments, asymptotics distributions for sample extreme statistics, and other statistical measures are obtained. The estimation of the parameters by the method of maximum-likelihood is discussed and the finite sample properties of the maximum-likelihood estimators (MLEs) are investigated numerically. A real data set is used to demonstrate its superior performance fit over several existing popular lifetime models.     

邓小平社会主义核心价值观教育思想探析

以泰州某大跨度连续梁桥的静动载试验为例，建立ANSYS和桥梁博士模型进行静动力有限元数值计算。将试验结果与模型计算值进行比较，试验结果表明,该桥结构刚度和承载能力满足设计要求。     

论水平扭剪应力场对大裂缝系统的控制

本文根据地质力学和岩体结构力学原理，探讨水平扭剪应力场在大裂缝系统形成、转化和分布中的重要控制作用及其物理模型．文中认为，大裂缝系统是较大的直压型裂缝网络与扭剪型裂缝网络叠加的产物，主要分布在较强的水平扭剪应力和术平直压应力复合作用的区块；水平扭剪应力场是改造和控制大裂缝网络结构异向性的最重要因素。这为研究和勘探较大的隐伏裂缝系统，提供了新的成藏模式和理论依据。     

“重陆轻海”与“通洋裕国”之海洋观刍议

明清两朝正处于世界性海洋历史发展的"千古变局"时代,但统治者沿袭传统模式,在立国思想上"重农抑商"、"重陆轻海",在国防战略上以"禁海"代替海防,禁海迁界、"守土防御",反映其海洋观念的淡薄;而东南沿海地方官员,尤其郑成功"通洋裕国"思想的提出和实践,显露出"以商立国",向海洋空间发展的意涵;传统时代"重陆轻海"与"通洋裕国"所反映的海洋观念,对国家民族发展的影响在某种程度上可以忽略不计,但大航海时代,海洋作为人类的第二生存空间影响到世界历史走向和发展格局时,"重陆轻海"观念所带来的深层影响会因此而改变国家和民族的命运。