Design two-level factorial experiments in blocks of size four

Recently, many researchers have devoted themselves to the investigation on the number of replicates needed for experiments in blocks of size two. In practice, experiments in blocks of size four might be more useful than those in blocks of size two. To estimate the main effects and two-factor interactions from a two-level factorial experiment in blocks, we might need many replicates. This article investigates designs with the least number of replicates for factorial experiments in blocks of size four. The methods to obtain such designs are presented.     

Copulas related to piecewise monotone functions of the interval and associated processes

In this work, we derive the copulas related to vectors obtained from the so-called chaotic stochastic processes. These are defined by the iteration of certain piecewise monotone functions of the interval [0, 1] to some initial random variable. We study some of its properties and present some examples. Since often these types of copulas do not have closed formulas, we provide a general approximation method which converges uniformly to the true copula. Our results cover a wide class of processes, including the so-called Manneville–Pomeau processes. The general theory is applied to the parametric estimation in certain chaotic processes. A Monte Carlo simulation study is also presented.     

A general long-term aging model with different underlying activation mechanisms: Modeling,Bayesian estimation,and case influence diagnostics

In this paper we propose a general cure rate aging model. Our approach enables different underlying activation mechanisms which lead to the event of interest. The number of competing causes of the event of interest is assumed to follow a logarithmic distribution. The model is parameterized in terms of the cured fraction which is then linked to covariates. We explore the use of Markov chain Monte Carlo methods to develop a Bayesian analysis for the proposed model. Moreover, some discussions on the model selection to compare the fitted models are given, as well as case deletion influence diagnostics are developed for the joint posterior distribution based on the ψ-divergence, which has several divergence measures as particular cases, such as the Kullback–Leibler (K-L), J-distance, L₁ norm, and χ²-square divergence measures. Simulation studies are performed and experimental results are illustrated based on a real malignant melanoma data.     

Slashed generalized exponential distribution

In this paper, we introduce an extension of the generalized exponential (GE) distribution, making it more robust against possible influential observations. The new model is defined as the quotient between a GE random variable and a beta-distributed random variable with one unknown parameter. The resulting distribution is a distribution with greater kurtosis than the GE distribution. Probability properties of the distribution such as moments and asymmetry and kurtosis are studied. Likewise, statistical properties are investigated using the method of moments and the maximum likelihood approach. Two real data analyses are reported illustrating better performance of the new model over the GE model.     

Slashed generalized Rayleigh distribution

We introduce a new family of distributions suitable for fitting positive data sets with high kurtosis which is called the Slashed Generalized Rayleigh Distribution. This distribution arises as the quotient of two independent random variables, one being a generalized Rayleigh distribution in the numerator and the other a power of the uniform distribution in the denominator. We present properties and carry out estimation of the model parameters by moment and maximum likelihood (ML) methods. Finally, we conduct a small simulation study to evaluate the performance of ML estimators and analyze real data sets to illustrate the usefulness of the new model.     

The effects of under‐skilling on need for recovery,losing employment and retirement intentions among older office workers: A prospective cohort study

Based on a sample of older workers from the Maastricht Cohort Study, the authors investigate the prevalence and dynamics of self‐reported under‐skilling and its effects on workers' need for recovery, their risk of losing employment and their retirement intentions over a two‐year period. They find that being under‐skilled is associated both with higher levels of need for recovery over time and with the risk of losing employment, but not with early retirement intentions. To achieve sustainable employment, they argue, the course of under‐skilling should be monitored throughout workers' careers, enabling timely interventions to avoid its negative consequences.     

Generating Dynamic Democratic Discussions: An Analysis of Teaching With U.S. Presidential Debates

Researchers have found that when young people participate in discussions of controversial political issues, they often become more politically engaged and informed (Hess, 2009 Hess, Diana E. (2009). Controversy in the classroom: The democratic power of discussion. New York, NY: Routledge.[Crossref] , [Google Scholar]). Nonetheless, some educators avoid fostering such discussions because they can become heated and distract from academic learning (Hess, 2002 Hess, Diana E. (2002). Discussing controversial public issues in secondary social studies classrooms: Learning from skilled teachers. Theory &; Research in Social Education, 30(1), 10–41.[Taylor &; Francis Online] , [Google Scholar]). Presidential elections, including the highly publicized debates, provide substantial material for discussions of major national and international issues, but no published research has examined how educators can leverage these events to generate productive civic learning experiences. In this article, we analyze data collected in seven high school classrooms during the 2012 presidential election to examine the challenges and opportunities associated with generating substantive, dynamic discussions of presidential debates. Our findings indicate that students enjoyed learning about candidates' different perspectives and that certain strategies were especially helpful for fostering substantive discussions: (a) scaffolding students' preparation for discussion; (b) providing opportunities for students to address open-ended questions; (c) redirecting students' engagement in competitive, interpersonal dynamics to learning about public issues; and (d) countering students' partisan tendencies. We discuss implications for practice and research and present a conceptual framework for generating dynamic, substantive democratic discussions.     

Discussing Global Issues Through Contemporary Art

Contemporary global issues can be examined through the lens of modern photographic art. In an effort to prepare global-ready graduates, this article explores the pressing problems of environmental degradation, urbanization, and homelessness through the work of three contemporary artists. Illustrative works, suggested approaches, and curriculum resources are provided.     

Developing a culturally-specific mixed methods approach to global research

With much of the development of mixed methods occurring through the works of scholars from the US, the UK, Canada, and the Anglos-Saxon/English-speaking countries, the discourse about a global research community must consider how it needs to be sensitive to diverse cultures. Clearly, the discussion must focus on adapting mixed methods to best fit the problems of countries, the cultural norms of conducting research, and the scholarly talents of in-country investigators. Unfortunately, the mixed methods literature is largely silent on diverse cultural adaptations of mixed methods.In this article, we first trace the involvement of worldwide countries in the historic development of mixed methods. Then, to gain a better understanding of the use and adaptation of mixed methods in diverse world academic cultures, we provide a qualitative study of themes mentioned by participants from seven different countries. From both the historical overview and the qualitative study, we end by making suggestions about specific strategies for a global discourse about mixed methods research, and suggest a de-colonizing presence of the Anglo-Saxon/English-speaking countries in the global expansion of mixed methods.     

Becoming a Race-Conscious Social Studies Teacher: The Influence of Personal and Professional Experiences

In this interpretive case study the researchers examined the beliefs of 13 self-identifying race-conscious secondary social studies teachers from diverse racial or ethnic, gender, and school-context backgrounds. The researchers found that the teachers' beliefs and views of practice were generally aligned with the main assertions of critical race theory. The teachers described their personal and professional experiences as a major influence on their race-conscious beliefs and views of practice. Moreover, teachers in diverse contexts described having to learn how to navigate the different racial experiences of the students in their classrooms, while teachers in racially segregated contexts (predominately White, Black, or Latino) emphasized the importance of teaching their students about others. Finally, despite the teachers' regular integration of race-related issues into their required and elective courses, they expressed a desire to have more opportunities to teach about race.