Variational bayes for modeling score distributions

Empirical modeling of the score distributions associated with retrieved documents is an essential task for many retrieval applications. In this work, we propose modeling the relevant documents’ scores by a mixture of Gaussians and the non-relevant scores by a Gamma distribution. Applying Variational Bayes we automatically trade-off the goodness-of-fit with the complexity of the model. We test our model on traditional retrieval functions and actual search engines submitted to TREC. We demonstrate the utility of our model in inferring precision-recall curves. In all experiments our model outperforms the dominant exponential-Gaussian model.     

Access to Schooling in a Post-Apartheid South Africa: Linking Concepts to Context

This paper focuses on the policy issue of expanding schooling in a post-apartheid South Africa. The Project of placing about two million children of school-going age in school is viewed as central to the rebuilding of South Africa. The paper argues that this project should be located within the peculiar history of this country's educational underdevelopment. Challenging the constraining influence of the New Right context should be central in conceptualising the provision of expanded school access. Access policy should be based on a notion of educational development that is linked to the overall socioeconomic development of this society. The view is promoted in this paper that a policy of quantitative expansion of schooling should not ignore the quality of such schooling.     

Hypocalcemia Presenting as Life Threatening Torsades de Pointes with Prolongation of QTc Interval

Torsades de pointes with prolonged QTc interval is a form of ventricular tachycardia. Many predisposing factors have been identified and hypocalcemia is among the rare ones. Our case illustrates that though rare, hypocalcemia might manifest as torsades de pointes with prolongation of QTc interval. Early diagnosis and management of dyselectrolytemia can prevent these patients from catastrophic torsades de pointes.     

Increasing evaluation sensitivity to diversity

Many queries have multiple interpretations; they are ambiguous or underspecified. This is especially true in the context of Web search. To account for this, much recent research has focused on creating systems that produce diverse ranked lists. In order to validate these systems, several new evaluation measures have been created to quantify diversity. Ideally, diversity evaluation measures would distinguish between systems by the amount of diversity in the ranked lists they produce. Unfortunately, diversity is also a function of the collection over which the system is run and a system’s performance at ad-hoc retrieval. A ranked list built from a collection that does not cover multiple subtopics cannot be diversified; neither can a ranked list that contains no relevant documents. To ensure that we are assessing systems by their diversity, we develop (1) a family of evaluation measures that take into account the diversity of the collection and (2) a meta-evaluation measure that explicitly controls for performance. We demonstrate experimentally that our new measures can achieve substantial improvements in sensitivity to diversity without reducing discriminative power.     

Gender differences in use and preferences of agricultural information sources in Pakistan

Purpose: Rural advisory services ensure agricultural information is disseminated to rural populations, yet they are less accessible to women. This research provides insight on gender differences in information access by investigating frequency of use and preference of agricultural information sources by gender in a rural setting, differentiated according to literacy and age. Design/Methodology/approach: This study interviewed 401 male/female individuals in farm households in Jhang and Bahawalpur district of Punjab, Pakistan in 2016. Findings: Men and women farmers’ use and preferences in accessing information sources are extremely different. Women hardly use sources for agricultural information, and value interpersonal communication from informal sources. In contrast, men use and value official agencies more. Radio, surprisingly, was very rarely used, contradicting previous findings of research elsewhere. Age and literacy affect differences between women more than it does between men, particularly for convenient locations to access information. Practical implications The study identified and refined major gender differences regarding use and preference for agricultural information in relation to age and literacy, and helps to articulate options to improve gender equality of access to agricultural information in Pakistan. Theoretical implications: The focus and outcomes regarding gender intersecting with age and literacy in agricultural information access imply the need for more refined socio-economic models, discerning and interrelating gender and other social dimensions beyond the standard of male-headed households. Originality/value: This paper adds to the growing body of evidence on information access according to gender, highlighting the need to investigate deeper socio-cultural issues around age and literacy.     

Placing Students at the Centre of the Decolonizing Education Imperative: Engaging the (Mis)Recognition Struggles of Students at the Postapartheid University

Misrecognition of South African university students is at the heart of this article. Misrecognition refers in this article to the exclusionary institutional discourses and practices of this country’s universities, which continue to prevent the majority of their (Black) students’ from achieving a successful education. It is a conceptual account of the ways in which these misrecognized students develop a complex educational life in their quest for a university education. The article argues that at the heart of students’ university experiences is an essential misrecognition of who they are, and how they access and encounter their university studies. I suggest that gaining greater purchase on their (mis)recognition struggles may place the university in a position to establish an engaging recognition platform to facilitate their educational success. Divided into four sections, the article starts with a rationale for bringing the institutional misrecognition of students into view. This is followed by a theoretical consideration of the notion of recognition, which opens space for what I call the recognitive agency of the education subject, who remains largely unknown to the university. The third section provides an account of the nature and extent of Black students’ survivalist educational navigations and practices in their family, community, school, and university contexts. The final and concluding section of the article presents a normative argument for developing an education platform for facilitating a productive encounter aimed at animating students’ educational becoming. This, I argue, should proceed on the basis of a decolonizing knowledge approach, involving curriculum recognition, which would accord students the conceptual tools for developing the epistemic virtues necessary for complex decolonized living.     

The reflexive adaptations of school principals in a ‘local’ South African space

This paper is an analysis of the work of three principals in an impoverished black township in post‐apartheid South Africa. Based on qualitative approaches, it discusses the principals’ entry into the township, and their navigation of their schools’ surrounding social dynamics. It combines the lenses of ‘space’ and ‘performance’ to analyse the reflexive basis on which they establish their principal roles. The paper suggests that their identities as principals were established in light of a range of engaged pedagogical performances. It is argued that these were enacted based on nuanced readings of their discursive environment and the enactment of strategic practices that provided them an authoritative platform for their principal roles.