The maximum likelihood estimators in the growth curve model with serial covariance structure

The maximum likelihood estimators of unknown parameters in the growth curve model with serial covariance structure under some conditions are derived in the paper.     

Relation of Parental Caring to Conspicuous Consumption Attitudes in Adolescents

Adolescent conspicuous consumption attitudes are perversely rooted in human relationships and interfere with personal growth and engagement in adult roles. Negative associations between parental caring and conspicuous consumption could be evidence of a compensatory motive to seek for the passing admiration of others when parent–child relationships fail to fulfill basic needs of competence, autonomy, and relatedness. Very little support, however, was found for Veblen’s original hypothesis that conspicuous consumption attitudes are driven by perceived social class distinctions. Yet, immersion in the consumer culture promoted by the media predicted higher levels of conspicuous consumption attitudes which were also more prominent among older adolescents. This small-scale study of 257, predominantly middle-class adolescents, calls attention to the need for more family socialization studies of adolescent money attitudes.     

Vertical and Horizontal Inequality in Ecuador: The Lack of Sustainability

We analyse the evolution of vertical and horizontal inequality in Ecuador in the long-run (1990–2016), as well as during and after the recent commodities boom (2005–2014). Using data from censuses, living standard measurement surveys, and employment surveys we show that Ecuador has made significant progress in reducing inequality, particularly since 2000. However, inequality has not decreased further since 2011. We argue that a key factor behind the reduction and ensuing stagnation of inequality is the dynamic of oil revenues, particularly regarding its effect on economic growth and on the financing of redistributive policies. Using the decomposition of the Gini coefficient by income source proposed by Lerman and Yitzhaki (Rev Econ Stat 67:151–156, 1985) we show that during the last decade there has been a shift away from market sources towards sources of income derived from government expenditures. Following the end of the commodities boom, this process is no longer sustainable. Indeed, we show that the underlying causes that led to the change in the sources of income started long before the end of the boom. The temporary shock following the 2008 financial crisis already affected the structure of Ecuador’s public finances and its current account. And, since around 2011, its institutions and labour market indicators have also deteriorated. We conclude that sustainable inequality reductions require improving the current institutions.

     

Comparative Study of Predictive Computational Models for Nanoparticle‐Induced Cytotoxicity

With the increasing use of nanomaterials incorporated into consumer products, there is a need for developing approaches to establish “quantitative structure‐activity relationships” (QSARs). These relationships could be used to predict various biological responses after exposure to nanomaterials for the purposes of risk analysis. This risk analysis is applicable to manufacturers of nanomaterials in an effort to determine potential hazards. Because metal oxide materials are some of the most widely applicable and studied nanoparticle types for incorporation into cosmetics, food packaging, and paints and coatings, we focused on comparing different approaches for establishing QSARs for this class of materials. Metal oxide nanoparticles are believed, by some, to cause alterations in cellular function due to their size and/or surface area. Others have said that these nanomaterials, because of the oxidized state of the metal, do not induce stress in biological tests systems. This controversy highlights the need to systematically develop structure‐activity relationships (i.e., the relationship between physicochemical features to the cellular responses) and tools for predicting potential biological effects after a metal oxide nanomaterial exposure. Here, we attempt to identify a set of properties of two specific metal oxide nanomaterials—TiO₂ and ZnO—that could be used to characterize and predict the induced cellular membrane damage of immortalized human lung epithelial cells. We adopt a mathematical modeling approach that uses the engineered nanomaterial size characterized as a dry nanopowder and the nanomaterial behavior in ultrapure water, phosphate buffer, and cell culture media to predict nanomaterial‐induced cellular membrane damage (via lactate dehydrogenase release). Results of these studies provide insights on how engineered nanomaterial features influence cellular responses and thereby outline possible approaches for developing and applying predictive computational models for biological responses caused by exposure to nanomaterials.     

Networks and Agricultural Development: The Case of Soybean Production and Consumption in Brazil

Diffusion theory and political economy are the two most common ways by which rural sociologists have explained the widespread use of agricultural innovations. In this paper, we argue, borrowing from science studies and using the empirical case of soybeans in Brazil, that the use of agricultural innovations is better understood as the result of the construction of networks of people and things. Thirty years ago soybean production in Brazil was insignificant. However, at that time a soybean network began to be formed. Initial actors were, among others, (1) soybean varieties produced in the United States, (2) wheat farmers located in the south of Brazil, and (3) soil in need of nitrogen, an expensive input for the new wheat varieties. State policies were no doubt important in consolidating that network. However, other persons, institutions and things were also necessary, including science and technology, the creation and/or expansion of farmers' organizations such as cooperatives, and the solution to the problem of photoperiod sensitivity in soybeans. We follow the soybean from its introduction in Brazil to its present status as an important crop. The overall context within which the soybean network began is also described. We conclude that the actor network approach is more congruent with the history of soybeans in Brazil than diffusion theory or political economy.     

Understanding Management Performance

Current models of the factors underlying management performance make use of a variety of variables at different levels of analysis. A framework is presented in which variables of three different types are linked together. Using data from a sample (n = 437) of British managers this article explores relationships between personality factors (using the big-five factors), work competencies and managerial performance. Results from the analyses reveal a set of underlying competency factors, which show different patterns of correlation with two facets of performance: current proficiency and promotability. In turn, these factors and the facets of performance show relationships with the big-five personality factors. Current proficiency is more closely related to competencies of organization, specialization and analysis – competencies more likely to be displayed by people who are conscientious and introverted. Promotability is linked more closely to competencies concerning action/motivation, flexibility/sensitivity and communication – competencies more likely to be displayed by people who are extroverted with lower conscientiousness and agreeableness.     

Family Discussion Groups for Patients with Chronic Pain: A Pilot Study

This pilot study investigated the benefits of discussion groups for patients with chronic pain and their family members. Nineteen patients with chronic pain and 41 relatives participated in four consecutive groups. Most patients and family members found their participation clearly helpful for themselves and for the family. The group helped them to improve communication, support and mutual relationships, and to better cope with the pain. Reported beneficial factors were experiencing communality, having a place to discuss things with each other, gaining insights, and learning from fellow‐sufferers and their own family. Post treatment, patients also felt less distressed by the pain, less depressed, less insufficient and showed an increase in life‐control and social activities. Moreover, some aspects of the family climate improved, but only in the perception of the family members. The present study points to the value of a multifamily format in chronic pain therapy and suggests the appropriateness of further controlled investigation.