Adolescent experiences with online racial discrimination: Implications for prevention and coping

Online aggression represents a wide range of negative experiences, including online discrimination targeting individuals based on race, but adolescent perspectives are not well-represented. We interviewed 15 adolescents regarding their experiences with online racial discrimination. After a phenomenological analysis, four main themes emerged: types of online racial aggression, processes supporting online racism, personal coping, and strategies to prevent online racial aggression. These themes provided insights into adolescent experiences, including feelings about targeted online racial discrimination, intersectionality with sexual harassment, and comfort through processing with friends. This study highlights adolescents' thoughts regarding advocacy, education, and social media reform to prevent online racial aggression. Future research should ensure that youth voices from minoritized racial backgrounds are integrated into efforts to address these critical social issues.     

Extending the Bradley–Terry model for paired comparisons to accommodate weights

In the method of paired comparisons (PCs), treatments are compared on the basis of qualitative characteristics they possess, in the light of their sensory evaluations made by judges. However, there may emerge the situations where in addition to qualitative merits/worths, judges may assign quantitative weights to reflect/specify the relative importance of the treatments. In this study, an attempt is made to reconcile the qualitative and the quantitative PCs through assigning quantitative weights to treatments having qualitative merits using/extending the Bradley–Terry (BT) model. Behaviors of the existing BT model and the proposed weighted BT model are studied through the test of goodness-of-fit. Experimental and simulated data sets are used for illustration.     

HIV prevention barriers in transgender women: a qualitative study

Abstract

Sexual contact is still one of the most important routes of HIV transmission. The aim of this study was identify the factors that underlie the higher prevalence of high-risk sexual behaviors in a sample of transgender women in Iran. The qualitative study used face-to-face, semi-structured, in-depth interviews in a sample of 15 transgender women. Our participants used sexual practices as a way to be approved/accepted as a woman. Using sex for this purpose led them to engage in high-risk sexual relationships. It is essential to consider these issues in consulting and education about high-risk behaviors.     

Decay patterns of invasive plants and plastic trash in urban streams

Urban streams are impacted by invasion of exotic riparian plants and the accumulation of plastic trash, which alter in-stream litter subsidies, and cause changes that cascade up the aquatic food web. The impacts of these factors on urban streams is poorly understood. We compared decay rates and invertebrate colonizers of 5 litter pack types in 4 urban streams in Victoria, British Columbia, Canada: Native Red alder (Alnus rubra) and Sitka willow (Salix sitchensis), invasive English ivy (Hedera sp.), Himalayan blackberry (Rubus armeniacus) and plastic trash (i.e. Styrofoam (polystyrene (PS)), plastic bag (high-density polyethylene (HDPE)), and Mylar (polyethylene terephthalate (PET). We tested 4 hypotheses: 1) exotic ivy and blackberry leaves would decay more slowly than native leaves; 2) exotic ivy and blackberry leaves would attract fewer and less diverse stream invertebrates than native leaves; 3) plastic trash would decay more slowly than leaves; and, 4) plastic trash would attract fewer and less diverse stream invertebrates than leaves. We found no difference between the leaf litter decay rates, however plastic trash decayed more slowly than leaves. Trash decay rates were faster than reported in marine environments, suggesting that plastic trash removal should be a management priority. Stream invertebrates colonized all pack types equally. We observed significant differences in litter decay rates and invertebrate assemblage alpha and Shannon–Wiener diversities across the 4 streams - likely related to differences in stream-specific environmental attributes including flashiness, stream discharge, and biological decay. We conclude that site-specific decay forces supersede litter quality in Pacific Coast urban streams.     

Selection of suitable prior for the Bayesian mixture of a class of lifetime distributions under type-I censored datasets

This paper explores the study on mixture of a class of probability density functions under type-I censoring scheme. In this paper, we mold a heterogeneous population by means of a two-component mixture of the class of probability density functions. The parameters of the class of mixture density functions are estimated and compared using the Bayes estimates under the squared-error and precautionary loss functions. A censored mixture dataset is simulated by probabilistic mixing for the computational purpose considering particular case of the Maxwell distribution. Closed-form expressions for the Bayes estimators along with their posterior risks are derived for censored as well as complete samples. Some stimulating comparisons and properties of the estimates are presented here. A factual dataset has also been for illustration.     

The single-index support vector regression model to address the problem of high dimensionality

ABSTRACT

The last few years, the applications of Support Vector Machine (SVM) for solving classification and regression problems have been increasing, due to its high performance and ability to transform the non-linear relationships among variables to linear form by employing the kernel idea (kernel function). In this work, we develop a semi-parametric approach to fit single-index models to deal with high-dimensional problems. To achieve this goal, we use support vector regression (SVR) for estimating the unknown nonparametric link function, while the single-index is determined by using the semi-parametric least squares method (Ichimura 1993). This development enhances the ability of SVR to solve high-dimensional problem. We design a three simulation examples with high-dimensional problems (linear and nonlinear). The simulations demonstrate the superior performance of the proposed method versus the standard SVR method. This is further illustrated by applying the real data.     

A comparison study of effectiveness and robustness of robust economic designs of T2 chart using genetic algorithm

ABSTRACT

Recently, researchers have tried to design the T² chart economically to achieve the minimum possible quality cost; however, when T² chart is designed, it is important to consider multiple scenarios. This research presents the robust economic designs of the T² chart where there is more than one scenario. An illustrative example is used to demonstrate the effect of the model parameters on the optimal designs. The genetic algorithm optimization method is employed to obtain the optimal designs. Simulation studies show that the robust economic designs of T² chart are more effective than traditional economic design in practice.     

Mathematical modelling to improve Rolled Throughput Yield in a supply chain

The outspread of supply chains competition entails inevitable application of quality improvement methods, such as Six Sigma. It is less than a decade that Six Sigma methodology has entered the supply chain scope; however, researches undertaken in this field have massively increased. Most of these research works have been done towards the application of the Six Sigma method for supply chain improvement, yet nothing has been done about suitable entity selection in supply chain for improvement. The purpose of this article is to propose a method for individual entity selection in the supply chain. Accordingly, a mixed integer non-linear programming model is presented that shows which supply chain entity should be selected, and how much to improve, in order to maximise financial benefit. This article also presents new comprehensive criteria based on the previous approach, which can measure the performance of the supply chain. Moreover, the ability of the proposed criteria is shown through a numerical example. Finally, the optimisation model was applied for selecting individual entity in tweedy supply chain in order to illustrate the capability of the model. In addition, sensitivity analysis is carried out on the parameters of the model.     

Signs of Divorce Before Marriage: The Role of Premarital Events in Iran

Premarital relationships form the basis for couples’ future relationships. There are certain factors in couples’ premarital relationships that could play a role in divorce. This study was conducted to investigate the role of premarital events (courtship, engagement, and Nikah [marriage]) in marital conflicts leading to divorce. In this qualitative study, which was carried out in Iran using the phenomenological method, 23 divorced applicants were purposefully selected, and their experiences and perceptions were examined. Data were collected using semistructured interviews. Analysis of interviews showed that little opportunity to get to know each other, neglecting the guidance of family members, disregarding signs of defect in the spouse, starting and continuing the relationship with lies and secrecy, infidelity, financial problems, and eventually ignoring the spouse’s appearance and its underestimation during the courtship period are special factors that predispose couples to divorce; however, couples, due to the special context of their relationships, ignore these factors. The findings of the study include implications for couple therapists, counselors, and couples’ families, and they can be useful in premarital education and postmarital interventions.