Budget-Constrained Item Cold-Start Handling in Collaborative Filtering Recommenders via Optimal Design

It is well known that collaborative filtering (CF) based recommender systems provide better modeling of users and items associated with considerable rating history. The lack of historical ratings results in the user and the item cold-start problems. The latter is the main focus of this work. Most of the current literature addresses this problem by integrating content-based recommendation techniques to model the new item. However, in many cases such content is not available, and the question arises is whether this problem can be mitigated using CF techniques only. We formalize this problem as an optimization problem: given a new item, a pool of available users, and a budget constraint, select which users to assign with the task of rating the new item in order to minimize the prediction error of our model. We show that the objective function is monotone-supermodular, and propose efficient optimal design based algorithms that attain an approximation to its optimum. Our findings are verified by an empirical study using the Netflix dataset, where the proposed algorithms outperform several baselines for the problem at hand.Comment: 11 pages, 2 figure

Bezlotoxumab for Prevention of Recurrent Clostridium difficile Infection

BACKGROUND Clostridium difficile is the most common cause of infectious diarrhea in hospitalized patients. Recurrences are common after antibiotic therapy. Actoxumab and bezlotoxumab are human monoclonal antibodies against C. difficile toxins A and B, respectively. METHODS We conducted two double-blind, randomized, placebo-controlled, phase 3 trials, MODIFY I and MODIFY II, involving 2655 adults receiving oral standard-of-care antibiotics for primary or recurrent C. difficile infection. Participants received an infusion of bezlotoxumab (10 mg per kilogram of body weight), actoxumab plus bezlotoxumab (10 mg per kilogram each), or placebo; actoxumab alone (10 mg per kilogram) was given in MODIFY I but discontinued after a planned interim analysis. The primary end point was recurrent infection (new episode after initial clinical cure) within 12 weeks after infusion in the modified intention-to-treat population. RESULTS In both trials, the rate of recurrent C. difficile infection was significantly lower with bezlotoxumab alone than with placebo (MODIFY I: 17% [67 of 386] vs. 28% [109 of 395]; adjusted difference, −10.1 percentage points; 95% confidence interval [CI], −15.9 to −4.3; P<0.001; MODIFY II: 16% [62 of 395] vs. 26% [97 of 378]; adjusted difference, −9.9 percentage points; 95% CI, −15.5 to −4.3; P<0.001) and was significantly lower with actoxumab plus bezlotoxumab than with placebo (MODIFY I: 16% [61 of 383] vs. 28% [109 of 395]; adjusted difference, −11.6 percentage points; 95% CI, −17.4 to −5.9; P<0.001; MODIFY II: 15% [58 of 390] vs. 26% [97 of 378]; adjusted difference, −10.7 percentage points; 95% CI, −16.4 to −5.1; P<0.001). In prespecified subgroup analyses (combined data set), rates of recurrent infection were lower in both groups that received bezlotoxumab than in the placebo group in subpopulations at high risk for recurrent infection or for an adverse outcome. The rates of initial clinical cure were 80% with bezlotoxumab alone, 73% with actoxumab plus bezlotoxumab, and 80% with placebo; the rates of sustained cure (initial clinical cure without recurrent infection in 12 weeks) were 64%, 58%, and 54%, respectively. The rates of adverse events were similar among these groups; the most common events were diarrhea and nausea. CONCLUSIONS Among participants receiving antibiotic treatment for primary or recurrent C. difficile infection, bezlotoxumab was associated with a substantially lower rate of recurrent infection than placebo and had a safety profile similar to that of placebo. The addition of actoxumab did not improve efficacy. (Funded by Merck; MODIFY I and MODIFY II ClinicalTrials.gov numbers, NCT01241552 and NCT01513239.

Introduction: Digital Youth and Religion

Public and academic discourse on the online activities of youth have been stormy and ambivalent at times (Lynn Schofield Clark 2013) [...

Legitimation of New Media for Religious Youth: Orthodox Elites’ Approach to Adolescent Youngsters’ Engagement with Digital Worlds

The promulgation of new media has generated substantial dilemmas for religious communities in terms of its use, implementation, and impact on youth’s socialization. Previous research has echoed religious authorities’ concern regarding the widespread integration of new media yet has done little to delineate their narratives of legitimation. Ergo, the question is begged, how do religious communities legitimate the use of new media? Utilizing a case study approach, this study focuses on the social construction of new media’s legitimacy within the Jewish Religious-Zionist community in Israel, through an analysis of the community’s educational elite. To this end, 26 in-depth interviews with the community’s prominent educational leaders were conducted. Findings indicate 4 primary narratives that are employed to legitimate new media use: (1) acclaiming modernity; (2) sanctifying the new media; (3) promoting solidarity; and (4) religious study and the public’s ability to choose. Understanding these narratives of legitimation towards new media sheds light on the ways that modern ideas are incrementally being integrated into religious communities, and the ways the elite negotiate its integration through what can be seen as their most weighty tool, that of youth socialization

Legitimation of New Media for Religious Youth: Orthodox Elites’ Approach to Adolescent Youngsters’ Engagement with Digital Worlds

The promulgation of new media has generated substantial dilemmas for religious communities in terms of its use, implementation, and impact on youth’s socialization. Previous research has echoed religious authorities’ concern regarding the widespread integration of new media yet has done little to delineate their narratives of legitimation. Ergo, the question is begged, how do religious communities legitimate the use of new media? Utilizing a case study approach, this study focuses on the social construction of new media’s legitimacy within the Jewish Religious-Zionist community in Israel, through an analysis of the community’s educational elite. To this end, 26 in-depth interviews with the community’s prominent educational leaders were conducted. Findings indicate 4 primary narratives that are employed to legitimate new media use: (1) acclaiming modernity; (2) sanctifying the new media; (3) promoting solidarity; and (4) religious study and the public’s ability to choose. Understanding these narratives of legitimation towards new media sheds light on the ways that modern ideas are incrementally being integrated into religious communities, and the ways the elite negotiate its integration through what can be seen as their most weighty tool, that of youth socialization

Smartphone Religious Networking: Negotiating Contested Identities within a Pious Community over WhatsApp

Online social networks can be considered harbingers of modernity and are claimed to encourage individualization in religious practices. Nevertheless, religious minority groups, including reclusive communities, legitimize their use for religious and communal purposes. Accordingly, social networks are emerging as dynamic third spaces of identity reflections on key issues of lived religion. This study examined how members of a religious group negotiate their identity over online social networks. Accordingly, we conducted a content analysis of 70 ultra-Orthodox Jewish public (Haredi) WhatsApp groups and 40 semi-structured interviews with participants. Findings revealed three primary facets of identity performance: communal affinity; proclaimed conformism and practiced agency; and contesting dogmatism and pragmatism. Through these facets, a new social identity is crystallized within the Haredi sector in Israel. Thus, the secluded spaces of WhatsApp groups enable a marginalized grassroots religious public to promote incremental social change without shattering communal boundaries

Smartphone Religious Networking: Negotiating Contested Identities within a Pious Community over WhatsApp

Online social networks can be considered harbingers of modernity and are claimed to encourage individualization in religious practices. Nevertheless, religious minority groups, including reclusive communities, legitimize their use for religious and communal purposes. Accordingly, social networks are emerging as dynamic third spaces of identity reflections on key issues of lived religion. This study examined how members of a religious group negotiate their identity over online social networks. Accordingly, we conducted a content analysis of 70 ultra-Orthodox Jewish public (Haredi) WhatsApp groups and 40 semi-structured interviews with participants. Findings revealed three primary facets of identity performance: communal affinity; proclaimed conformism and practiced agency; and contesting dogmatism and pragmatism. Through these facets, a new social identity is crystallized within the Haredi sector in Israel. Thus, the secluded spaces of WhatsApp groups enable a marginalized grassroots religious public to promote incremental social change without shattering communal boundaries