Variations of the elephant random walk

In the classical simple random walk the steps are independent, that is, the walker has no memory. In contrast, in the elephant random walk, which was introduced by Schütz and Trimper [19] in 2004, the next step always depends on the whole path so far. Our main aim is to prove analogous results when the elephant has only a restricted memory, for example remembering only the most remote step(s), the most recent step(s), or both. We also extend the models to cover more general step sizes.

The MLKL kinase-like domain dimerization is an indispensable step of mammalian MLKL activation in necroptosis signaling

MLKL phosphorylation by RIP3 is the commitment step of necroptosis execution, which could induce MLKL activation featured as MLKL monomer-oligomer transition. Here, we reported that the dimerization of the MLKL kinase-like domain was the direct consequence of RIP3 triggered MLKL-phosphorylation. Two inter-dimer interfaces were found in the crystal structure of human MLKL. Mutations destroying both interfaces could prevent RIP3-induced MLKL oligomerization and necroptosis efficiently. Moreover, we confirmed MLKL self-assembly by the internal coiled-coil region is necessary for MLKL oligomerization and function. The mutations disrupting coiled-coil self-assembly repressed necroptosis, but it did not prevent RIP3-induced dimerization of the MLKL kinase-like domain. So that, MLKL activation is a sequential process, which begins with kinase-like domain dimerization, and followed by internal coiled-coil region self-assembly to form a proper MLKL oligomer. Besides human MLKL, structural and functional analysis showed the kinase-like domain dimerization was conserved among mammalian species, suggesting it is a general step of the RIP3-induced MLKL activation process.

Testing the Validity of a Link Function Assumption in Repeated Type-II Censored General Step-Stress Experiments

In step-stress experiments, test units are successively exposed to higher usually increasing levels of stress to cause earlier failures and to shorten the duration of the experiment. When parameters are associated with the stress levels, one problem is to estimate the parameter corresponding to normal operating conditions based on failure data obtained under higher stress levels. For this purpose, a link function connecting parameters and stress levels is usually assumed, the validity of which is often at the discretion of the experimenter. In a general step-stress model based on multiple samples of sequential order statistics, we provide exact statistical tests to decide whether the assumption of some link function is adequate. The null hypothesis of a proportional, linear, power or log-linear link function is considered in detail, and associated inferential results are stated. In any case, except for the linear link function, the test statistics derived are shown to have only one distribution under the null hypothesis, which simplifies the computation of (exact) critical values. Asymptotic results are addressed, and a power study is performed for testing on a log-linear link function. Some improvements of the tests in terms of power are discussed.

Analyzing Age-Period-Cohort Data: A Review and Critique

Age-period-cohort (APC) analysis has a long, controversial history in sociology and related fields. Despite the existence of hundreds, if not thousands, of articles and dozens of books, there is little agreement on how to adequately analyze APC data. This article begins with a brief overview of APC analysis, discussing how one can interpret APC effects in a causal way. Next, we review methods that obtain point identification of APC effects, such as the equality constraints model, Moore-Penrose estimators, and multilevel models. We then outline techniques that entail point identification using measured causes, such as the proxy variables approach and mechanism-based models. Next, we discuss a general framework for APC analysis grounded in partial identification using bounds and sensitivity analyses. We conclude by outlining a general step-by-step procedure for conducting APC analyses, presenting an empirical example examining temporal shifts in verbal ability.

A comprehensive review of disputes prevention and resolution in construction projects

The construction industry is complex, fragmented, dynamic and involves many parties in an adversarial relationship. This makes disputes almost inevitable in any construction project. This paper aims to provide a comprehensive review of the adopted methodologies in resolving disputes that arise in the construction projects. The paper evaluates and classifies the different methods of disputes resolution. A comparison was conducted between the advantages and disadvantages of each method. The paper distinguishes between the traditional method of disputes resolution; litigation and Alternative Dispute Resolution (ADR) methods such as arbitration, mediation, med/arb, mini-trial and dispute review board. In conclusion there is no best way to solve all kind of disputes in construction projects, however, a general step by step process of how disputes should be addressed is finally presented.

Teacher trainers’ self-reflection and self-evaluation

Introduction: A group of researchers have worked out the Teacher Trainers’ Professional Competences in Hungary. The aim of the research was to explore whether there are any differences among certain groups of teacher trainers concerning their self-reflection, self-evaluation and commitment to ongoing professional development. Methods: Structured interviews were carried out with a sample of 6 teacher trainers whose selection was based on two principles - those who are considered to be teacher trainers in Hungary and those who are available in one of the most important teacher training centres in Hungary - Eszterházy Károly University. The data analysis was done with the General Step-by Step Model of Qualitative Content Analysis supported by MAXQDA 12 software programme. Results: Self-reflection and self-evaluation are the most important factors in teacher trainers’ professional development. Existing standards and criteria to which they compare their achievements play an orienteering role in these two processes, as well as in their self-regulatory learning. However, the levels, the types and the methods of self-reflection can differ depending on what field of teacher training they are involved in and when they were trained as teachers. Discussion: The results of the study promote deeper understanding of teacher trainers’ professional competences regarding their commitment to professional development. It has been clearly stated for which group of teacher trainers scientific research as the highest level of reflection can be a basic requirement, and for which group it should be an expected learning outcome in the future. As research-based teacher training is being introduced in Hungary, parallel to it, all groups of teacher trainers will gradually be expected to carry out scientific research to accomplish the highest level of reflection. Limitations: The sample size does not cover the whole scope of teacher trainers, as instructors teaching specific disciplines were not interviewed, and the research was done in qualitative design, therefore the results cannot be generalized. A future research of quantitative design should cover more teacher trainers from other universities and regions. Conclusions: The general step by step model of qualitative content analysis has provided a detailed picture of the driver of the teacher trainers’ professional development. The evidence of the acceptance of the position of a role model for their instructed, mentored or supported student teachers, teacher assistants and teachers has been given by this research. The need for research-based teacher training in Hungary has been confirmed. Further research should be carried out focusing on teaching strategies, methods and good practices where self-reflection and self-evaluation play a crucial role in enhancing self-regulatory learning