Efficiency of a Linear Combination of the Median and the Sample Mean: The Double Truncated Normal Distribution

Abstract.  We characterize all symmetric location models for which a linear combination of the median and the sample mean is an asymptotically efficient estimator of the location parameter. The resulting model can be understood as a symmetrized or double truncated normal distribution. A simple algorithm to estimate the parameters is given and an application is presented.     

Assessing Health Endowment,Access and Choice Determinants: Impact on Retired Europeans’ (In)activity and Quality of Life

A future for the E.U., dominated by an ever-increasing population of retired citizens represents a major challenge to social and health policy in European countries. Under Rowe and Kahn’s (Gerontol 37(4):433–440, 1997) perspective on positive aging, this paper is interested in exploring the role of health on citizens’ active participation after retirement and social engagement to life and quality of life. This paper also aims at finding whether Sen’s (Public health, ethics, and equity. Oxford University Press, Oxford, 2004) capability approach or cumulative disadvantage or advantage theory relative to the access to health also verifies in a context of multi-national developed economies. The first part of this study is therefore concerned with generating a health indicator that enables this, whilst controlling for individual heterogeneity in self-rated health responses from 10,859 retired individuals from the SHARE survey. Socioeconomic determinants of health are found not to be critical in determining health in such a developed context whilst cumulative advantage is found relevant for the positive aging of Europeans. Evidence is found that active engagement in activities and quality of life are most certainly a prerogative for the more educated and the healthier retirees, hinting a strategy for European policymakers: cumulative advantage, leveraged by education and health policy, might just be the long-term strategy for contouring an aging and unproductive European population, transforming what could be a ‘burden’ into an asset.     

Empirical likelihood for nonlinear models with missing responses

In this paper, a nonlinear model with response variables missing at random is studied. In order to improve the coverage accuracy for model parameters, the empirical likelihood (EL) ratio method is considered. On the complete data, the EL statistic for the parameters and its approximation have a χ² asymptotic distribution. When the responses are reconstituted using a semi-parametric method, the empirical log-likelihood on the response variables associated with the imputed data is also asymptotically χ². The Wilks theorem for EL on the parameters, based on reconstituted data, is also satisfied. These results can be used to construct the confidence region for the model parameters and the response variables. It is shown via Monte Carlo simulations that the EL methods outperform the normal approximation-based method in terms of coverage probability for the unknown parameter, including on the reconstituted data. The advantages of the proposed method are exemplified on real data.     

Maximum likelihood estimator in a multi-phase random regression model

We consider a random regression model with several-fold change-points. The results for one change-point are generalized. The maximum likelihood estimator of the parameters is shown to be consistent, and the asymptotic distribution for the estimators of the coefficients is shown to be Gaussian. The estimators of the change-points converge, with n ^?1 rate, to the vector whose components are the left end points of the maximizing interval with respect to each change-point. The likelihood process is asymptotically equivalent to the sum of independent compound Poisson processes.     

The effect of temporal aggregation on the estimation accuracy of ARMA models

ABSTRACT

Autoregressive Moving Average (ARMA) time series model fitting is a procedure often based on aggregate data, where parameter estimation plays a key role. Therefore, we analyze the effect of temporal aggregation on the accuracy of parameter estimation of mixed ARMA and MA models. We derive the expressions required to compute the parameter values of the aggregate models as functions of the basic model parameters in order to compare their estimation accuracy. To this end, a simulation experiment shows that aggregation causes a severe accuracy loss that increases with the order of aggregation, leading to poor accuracy.     

Model selection by LASSO methods in a change-point model

The paper considers a linear regression model with multiple change-points occurring at unknown times. The LASSO technique is very interesting since it allows simultaneously the parametric estimation, including the change-points estimation, and the automatic variable selection. The asymptotic properties of the LASSO-type (which has as particular case the LASSO estimator) and of the adaptive LASSO estimators are studied. For this last estimator the Oracle properties are proved. In both cases, a model selection criterion is proposed. Numerical examples are provided showing the performances of the adaptive LASSO estimator compared to the least squares estimator.     

Spatial–temporal modellization of the $$\hbox {NO}_{2}$$ concentration data through geostatistical tools

The nitrogen dioxide is a primary pollutant, regarded for the estimation of the air quality index, whose excessive presence may cause significant environmental and health problems. In the current work, we suggest characterizing the evolution of \(\hbox {NO}_{2}\) levels, by using geostatistical approaches that deal with both the space and time coordinates. To develop our proposal, a first exploratory analysis was carried out on daily values of the target variable, daily measured in Portugal from 2004 to 2012, which led to identify three influential covariates (type of site, environment and month of measurement). In a second step, appropriate geostatistical tools were applied to model the trend and the space–time variability, thus enabling us to use the kriging techniques for prediction, without requiring data from a dense monitoring network. This methodology has valuable applications, as it can provide accurate assessment of the nitrogen dioxide concentrations at sites where either data have been lost or there is no monitoring station nearby.     

Culturally sensitive social work: promoting cultural competence

In current times of great conflict and clashes between different cultures and worldviews, cultural competencies should be a well embedded feature of social work education. This is a fundamental and cross-cutting issue; however, we question whether it is an obvious concern in social work education in European countries, specifically in Portugal, and if the curriculum of social work courses covers this topic. This article is based on research that seeks to find out if there are mandatory curricular units of the disciplinary field of social work that explicitly address culturally sensitive social work and cultural competencies. Thus, this article presents a study that focuses on educational institutions that provide social work courses in Portugal, and has the potential to be extended to other countries. An online survey and a document analysis of the curriculum programmes of all Portuguese courses in social work were conducted. The study results revealed the lack of curricular units with clear terms relating to the topic of culturally sensitive social work. The implications for practice and educational policy are also discussed, which lead to a reflection and analysis of the evaluation and accreditation process of social work education in Portugal, with a conclusion that it is incomplete and faces major challenges in curriculum development and course accreditation. Challenges and opportunities in developing social work curricula, as well the debate around a generic or specialist social work education are also discussed. Finally, the authors suggest an opportunity to develop cultural competencies through continuing and lifelong learning for social workers.     

Business Coach – nicht nur fürs Business

In many organizations business coaching is one of the favorite personnel development tools. The focus is clearly on economical targets. In these days, however, this is not enough to accompany managers successfully. The results of a qualitative empirical study show that not only business related topics but also relevant personal topics of a manager should be integrated into a coaching process to ensure lasting work improvements as well as any necessary individual development.     

Validity evidence of the Portuguese adaptation of the Ambivalent Sexism Inventory / Evidencias de validez de la adaptación portuguesa de la Escala de Sexismo Ambivalente

Abstract

Modern forms of sexism have promoted the development of new scales and evaluation tools. The Ambivalent Sexism Inventory (ASI) (Glick & Fiske, 1996) aims to assess sexism along two dimensions: hostile sexism and benevolent sexism. The aim of this study is to present evidence of the validity of the factor structure of the Portuguese version of the ASI by analysing its structure and its relationships with neosexism and social dominance. The sample consisted of 446 Portuguese participants (68.6% female) between 17 and 77 years old. Results confirmed the two-factor structure; however, the best fit was registered with a four-factor structure: one hostile factor and three benevolent factors. Both hostile and benevolent sexism were correlated with neosexism and social dominance orientation. Future research should explore the dimensionality of the scale based on a four-dimension structure and its relationship to others sexism issues.