University of Illinois at Chicago

About: University of Illinois at Chicago is a education organization based out in Chicago, Illinois, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 57071 authors who have published 110536 publications receiving 4264936 citations.

A random-effects ordinal regression model for multilevel analysis.

Abstract: A random-effects ordinal regression model is proposed for analysis of clustered or longitudinal ordinal response data. This model is developed for both the probit and logistic response functions. The threshold concept is used, in which it is assumed that the observed ordered category is determined by the value of a latent unobservable continuous response that follows a linear regression model incorporating random effects. A maximum marginal likelihood (MML) solution is described using Gauss-Hermite quadrature to numerically integrate over the distribution of random effects. An analysis of a dataset where students are clustered or nested within classrooms is used to illustrate features of random-effects analysis of clustered ordinal data, while an analysis of a longitudinal dataset where psychiatric patients are repeatedly rated as to their severity is used to illustrate features of the random-effects approach for longitudinal ordinal data.

#Gamergate and The Fappening: How Reddit’s algorithm, governance, and culture support toxic technocultures

Abstract: This article considers how the social-news and community site Reddit.com has become a hub for anti-feminist activism. Examining two recent cases of what are defined as “toxic technocultures” (#Gamergate and The Fappening), this work describes how Reddit’s design, algorithm, and platform politics implicitly support these kinds of cultures. In particular, this piece focuses on the ways in which Reddit’s karma point system, aggregation of material across subreddits, ease of subreddit and user account creation, governance structure, and policies around offensive content serve to provide fertile ground for anti-feminist and misogynistic activism. The ways in which these events and communities reflect certain problematic aspects of geek masculinity are also considered. This research is informed by the results of a long-term participant-observation and ethnographic study into Reddit’s culture and community and is grounded in actor-network theory.

Microbial arsenic: from geocycles to genes and enzymes.

Abstract: Arsenic compounds have been abundant at near toxic levels in the environment since the origin of life. In response, microbes have evolved mechanisms for arsenic resistance and enzymes that oxidize As(III) to As(V) or reduce As(V) to As(III). Formation and degradation of organoarsenicals, for example methylarsenic compounds, occur. There is a global arsenic geocycle, where microbial metabolism and mobilization (or immobilization) are important processes. Recent progress in studies of the ars operon (conferring resistance to As(III) and As(V)) in many bacterial types (and related systems in Archaea and yeast) and new understanding of arsenite oxidation and arsenate reduction by respiratory-chain-linked enzyme complexes has been substantial. The DNA sequencing and protein crystal structures have established the convergent evolution of three classes of arsenate reductases (that is classes of arsenate reductases are not of common evolutionary origin). Proposed reaction mechanisms in each case involve three cysteine thiols and S–As bond intermediates, so convergent evolution to similar mechanisms has taken place.