Gateway finder in large graphs: problem definitions and fast solutions

Given a graph, how to find a small group of ‘gateways’, that is a small subset of nodes that are crucial in connecting the source to the target? For instance, given a social network, who is the best person to introduce you to, say, Chris Ferguson, the poker champion? Or, given a network of people and skills, who is the best person to help you learn about, say, wavelets? We formally formulate this problem in two scenarios: Pair-Gateway and Group-Gateway. For each scenario, we show that it is sub-modular and thus it can be solved near-optimally. We further give fast, scalable algorithms to find such gateways. Extensive experimental evaluations on real data sets demonstrate the effectiveness and efficiency of the proposed methods.     

Word Reading Fluency: Role of Genome‐Wide Single‐Nucleotide Polymorphisms in Developmental Stability and Correlations With Print Exposure

The genetic effects on individual differences in reading development were examined using genome‐wide complex trait analysis (GCTA) in a twin sample. In unrelated individuals (one twin per pair, n = 2,942), the GCTA‐based heritability of reading fluency was ~20%–29% at ages 7 and 12. GCTA bivariate results showed that the phenotypic stability of reading fluency from 7 to 12 years (r = 0.69) is largely driven by genetic stability (genetic r = 0.69). Genetic effects on print exposure at age 12 were moderate (~26%) and correlated with those influencing reading fluency at 12 (genetic r = 0.89), indicative of a gene–environment correlation. These findings were largely consistent with quantitative genetic twin analyses that used both twins in each pair (n = 1,066–1,409).     

Comorbidity of PTSD in anxiety and depressive disorders: Prevalence and shared risk factors

The present study aims to assess comorbidity of posttraumatic stress disorder (PTSD) in anxiety and depressive disorders and to determine whether childhood trauma types and other putative independent risk factors for comorbid PTSD are unique to PTSD or shared with anxiety and depressive disorders. The sample of 2402 adults aged 18–65 included healthy controls, persons with a prior history of affective disorders, and persons with a current affective disorder. These individuals were assessed at baseline (T0) and 2 (T2) and 4 years (T4) later. At each wave, DSM-IV-TR based anxiety and depressive disorder, neuroticism, extraversion, and symptom severity were assessed. Childhood trauma was measured at T0 with an interview and at T4 with a questionnaire, and PTSD was measured with a standardized interview at T4. Prevalence of 5-year recency PTSD among anxiety and depressive disorders was 9.2%, and comorbidity, in particular with major depression, was high (84.4%). Comorbidity was associated with female gender, all types of childhood trauma, neuroticism, (low) extraversion, and symptom severity. Multivariable significant risk factors (i.e., female gender and child sexual and physical abuse) were shared among anxiety and depressive disorders. Our results support a shared vulnerability model for comorbidity of anxiety and depressive disorders with PTSD. Routine assessment of PTSD in patients with anxiety and depressive disorders seems warranted.     

A Proposal for Motivating Research

We use an experimental course collaboration that occurred in the winter of 2012 as a case study for an approach to interdisciplinary collaboration between Theatre and Humanities courses, and we argue that the theatre methodology of “devising” can serve as a particularly rich locus for collaboration between Theatre students and other Humanities students because it allows students to cooperate in generating a creative product that draws on two different areas of expertise. In this case, English students operated as critically informed advisors for Theatre students who devised original performances using a canonical text as source material. This experimental collaboration produced many of the positive results that have been discussed in previous studies concerning interdisciplinary pedagogy, including thoughtful consideration of the nature of each discipline, transferring of tools and methodologies between disciplines, increased student enthusiasm, and faculty development. However, it did not require extensive resources or curricular restructuring and thus might operate as a useful model for instructors with reservations about or limited resources for attempting interdisciplinary collaboration.     

International Communications

Church, Communication, Development (Committee on Society, Development, and Peace; Publications Department; Ecumenical Centre, 150 Route de Ferney, 1211 Geneva 20, Switzerland, $3.50)

Ithiel de Sola Pool, Philip Stone and Alexander Szalai's Communications, Computers and Automation for Development (UNITAR Research Reports No. 6, UNITAR, 801 United Nations Plaza, New York 10017, $2.00)

George Melly's Revolt into Style: the Pop Arts in Britain (Penguin [hardback], $8.95)

T.C. Worsley's Television: The Ephemeral Art (London: Alan Ross, $9.00)

D.G. Bridson's Prospero and Ariel: The Rise and Fall of Radio—A Personal Recollection (London: Gollancz, $10.50)

Raymond Durgnat's A Mirror for England: British Movies from Austerity to Affluence (Praeger, $11.95)

Asa Briggs History of Broadcasting in the United Kingdom (Oxford University Press, 1961, 1965)     

The audience product and the new media environment: Implications for the economics of media industries

Abstract

The issues currently facing the book publishing industry are profound and the resolution of these issues will ultimately affect how the industry is defined in the future. One of the most important issues that the industry faces is the emergence of a whole range of new media which have created important managerial tensions within the book publishing firms. These tensions include defining what a book is in light of the multi‐dimensional content available as well as the development of new modes of delivery; whether to remain focused on producing great content or become a more technologically oriented company; and the best organizational approach. While these tensions may be viewed as creating turmoil, they have been catalysts of change and are creating opportunities that will ultimately enable the industry to regenerate its businesses, reach a new generation of readers, and create an environment that is more conducive to innovation.     

Exploring the Principal's Contribution to School Effectiveness: 1980‐1995∗

This article reviews research from 1980‐1995 exploring the relationship between principal leadership and student achievement. The focuses is on the substantive findings that emerged from the review. Earlier reports focused on conceptual and methodological issues. The general pattern of results drawn from this review supports the belief that principals exercise a measurable, though indirect effect on school effectiveness and student achievement. While this indirect effect is relatively small, it is statistically significant and supports the general belief among educators that principals contribute to school effectiveness and improvement. Moreover, the review suggests that previously described discrepancies in research results may be explained by the conceptual and methodological tools employed by researchers. We also emphasize the limitations of these studies. Even taken as a group they do not resolve the most important theoretical and practical issues concerning the means by which principals achieve an impact on school outcomes and how contextual forces influence the exercise of leadership in the schoolhouse. It is concluded that while substantial progress has been made over the past 15 years in understanding the principal's contribution to school effectiveness, the most important scholarly and practical work lies ahead. In addition to this qualified, we assert that scholars are better equipped conceptually and methodologically to address these challenges than in 1980.

     

Children's understanding of substances,part 1: recognizing chemical change

Arising from a study which explored the development children's concept of a substance (ages 11-14), this two-part paper focuses on the idea of chemical change. Part one considers substance identity and pupils' interaction with the scientific idea of melting and boiling behaviour as a means for identification and the assessment of purity. Evidence is presented which suggests that children do not 'naturally' have a concept of substance identity which allows them to recognize chemical change as a possibility. Instead, their thinking is in terms of the history of samples. The scientific idea of identity led to a confrontation with the idea of chemical change but the pupils were unwilling to accept this phenomenon. The preference was to view the product of a chemical change as a 'mix' of the original substances rather than as a substance in its own right. Implications for teaching are discussed. Part two (in press) goes on to examine the issue of explaining chemical change.