Evaluation of corporate governance systems by credit rating agencies

In periods of high market volatility, and in order to minimize their risks, some investors prefer to invest their funds in well-governed companies. This paper aims to describe the methodology used by rating agencies to assess corporate governance systems (CGS) and to compare agencies’ practices. More and more the shareholders and creditors incorporate mechanisms related to CGS in the assessment of risks. Using a sample of five rating agencies, we distill 51 governance criteria to two governance factors using principal components analysis. The first factor represents the “shareholders rights and board of directors”. The second one is related to “remuneration policy and convergence of interests for shareholders and managers”. We identify three different business models for the corporate governance rating process.     

«Il n'y a pas d’avenir dans ce métier.» Être chauffeur de VTC en Afrique par temps de pandémie

Si les plateformes ont donné du travail à beaucoup d’Africains, les emplois créés sont de mauvaise qualité, comme la pandémie l'a bien montré. Dans ce contexte, les auteurs examinent la situation particulière des chauffeurs VTC en Afrique en s'appuyant sur des entretiens approfondis, réalisés au Kenya, et sur les méthodes de l'ethnographie virtuelle. Ils montrent que ces travailleurs ont recours à un «régime de débrouille», associant résilience, réajustement et résistance. Pour améliorer les conditions de travail et lutter contre la précarité dans le secteur, il faut à la fois que les pouvoirs publics instaurent des cadres réglementaires et que les travailleurs se mobilisent collectivement.     

The social work services in screening process of compulsory treatment interventions in addicts in Iran: A content analysis study

Compulsory treatment has had a detrimental impact on drug abuse treatment policies and programs in Iran. Physicians are currently required to conduct initial treatment screening. Social workers are a part of the treatment team but have no authority to initiate a compulsory drug treatment plan. For this reason, the present article investigates social work service participation in the process of compulsory drug treatment. The study methodology is content analysis. Nine social workers participated in seven focus group discussions. Overall, 110 codes were extracted from the sessions and were categorized into five main themes: interview and initial assessment; referral; investigation of ineligibility criteria; report to judicial authority; and follow‐up and advocacy. The results of this research suggest amending executive bylaws based on a social work approach to the screening process for compulsory drug treatment.     

Exclusion of HIV-positive people with disabilities in the media

This current issue piece aims to address the harmful exclusion of people with disabilities in the Iranian media. In a case study, this author collected news related to statistics of HIV-positive people covered by popular news websites written in the Persian language between June 2011 and June 2012. Within the analysed electronic texts, no reference was made to the number of HIV-positive people with disabilities. Under the rubric of critical discourse analysis, one can argue that this lack of representation may also be linked to a more general level of discourse that constitutes the marginalization of people with disabilities. This damaging exclusion both legitimizes and reproduces the ideology that people with disabilities are social minorities who can be excluded to the benefit of powerful people. This current issue piece also discusses the potential negative consequences of excluding HIV-positive people with disabilities from the discourse of HIV/AIDS in the media. Ultimately, the conceivable reasons for the Iranian government failure or refusal to publish the statistics of HIV-positive people with disabilities will be provided. Studies from various countries could shed more light on the exclusion of HIV-positive people with disabilities in the media and the interplay between HIV/AIDS and disability issues.     

An economical acceptance–rejection algorithm for uniform random variate generation over constrained simplexes

This paper develops an algorithm for uniform random generation over a constrained simplex, which is the intersection of a standard simplex and a given set. Uniform sampling from constrained simplexes has numerous applications in different fields, such as portfolio optimization, stochastic multi-criteria decision analysis, experimental design with mixtures and decision problems involving discrete joint distributions with imprecise probabilities. The proposed algorithm is developed by combining the acceptance–rejection and conditional methods along with the use of optimization tools. The acceptance rate of the algorithm is analytically compared to that of a crude acceptance–rejection algorithm, which generates points over the simplex and then rejects any points falling outside the intersecting set. Finally, using convex optimization, the setup phase of the algorithm is detailed for the special cases where the intersecting set is a general convex set, a convex set defined by a finite number of convex constraints or a polyhedron.     

Bayesian analysis of covariance under inverse Gaussian model

This paper considers the problem of analysis of covariance (ANCOVA) under the assumption of inverse Gaussian distribution for response variable from the Bayesian point of view. We develop a fully Bayesian model for ANCOVA based on the conjugate prior distributions for parameters contained in the model. The Bayes estimator of parameters, ANCOVA model and adjusted effects for both treatments and covariates along with predictive distribution of future observations are developed. We also provide the essentials for comparing adjusted treatments effects and adjusted factor effects. A simulation study and a real world application are also performed to illustrate and evaluate the proposed Bayesian model.     

Inferences on stress–strength parameter based on GLD5 distribution

Let X and Y be independent random variables distributed as generalized Lindley distribution type 5 (GLD5). This article deals with the estimation of the stress–strength parameter R = P(Y < X), which plays an important role in reliability analysis. For this purpose, the maximum likelihood and the uniformly minimum variance unbiased estimators are presented in the explicit form. Moreover, considering Arnold and Strauss’ bivariate Gamma distribution as an informative prior and Jeffreys’ as noninformative prior, the Bayes estimators are derived. Various bootstrap confidence intervals are also proposed and, finally, the presented methods are compared using a simulation study.     

Necessary and sufficient conditions for stochastic orders between (n − r + 1)-out-of-n systems in proportional hazard (reversed hazard) rates model

Consider two (n ? r + 1)-out-of-n systems, one with independent and non-identically distributed components and another with independent and identically distributed components. When the lifetimes of components follow the proportional hazard rates model, we establish a necessary and sufficient condition for the usual stochastic order to hold between the lifetimes of these two systems. For the special case of r = 2, some generalized forms of this result to the hazard rate, dispersive and likelihood ratio orders are also obtained. Moreover, for the case when the lifetimes of components follow the proportional reversed hazard rates model, we derive some similar results for comparing the lifetimes of two systems . Applications of the established results to different situations are finally illustrated.     

Some new results on aggregate claim amounts from two heterogeneous Marshall–Olkin extended exponential portfolios

In this work, we discuss some stochastic comparisons of two aggregate claim amounts. Applications of our results to the value-at-risk and tail-value-at-risk are also mentioned. It is also shown that the aggregate claim amounts of risks exhibiting a weak form of dependence known as positive cumulative dependence (negatively associated) is larger (smaller) in convex order than the corresponding aggregate claim amounts under the theoretical independence assumption. The obtained results show that the correlations between individual risks increase stop-loss premiums corresponding to aggregate claim amounts. The results established here complete and extend the results of Barmalzan, Payandeh Najafabadi, and Balakrishnan (2017 Barmalzan, G., A. T. Payandeh Najafabadi, and N. Balakrishnan. 2017. Ordering results for aggregate claim amounts from two heterogeneous Marshall–Olkin extended exponential portfolios and their applications in insurance analysis. Theory of Probability and its Applications(to appear). [Google Scholar], Theory of Probability and its Applications, to appear).