Effects of Positions in Knowledge Networks on Trust

This paper empirically explores relations between network positions in knowledge networks and trust. In social network theory the closure argument and the gossip argument describe this relation. These two arguments do not distinguish between different dimensions of trust. In this paper we estimate effects of closure positions on two dimensions of trust (trust in abilities and trust in intentions). The closure argument emphasizes that dense network structures enforce individuals to be trustworthy. The gossip argument emphasizes that dense networks amplifies gossip. Since it was found that different network positions are optimal for different tasks, we propose that the content of a network is an intrinsic characteristic of a network that influences whether gossip is neutral or judgmental. To discern between different contents we consider two task-specific knowledge networks. Empirical data were collected on a network of 55 individuals in the setting of account management. These data strongly support the gossip argument for both dimensions of trust. However, the data only gave weak and ambiguous support for the closure argument

Effect of Geometer’s Sketchpad on Student Knowledge and Attitude

This study examines the effects of Geometer’s Sketchpad on student achievement and attitudes in algebra classrooms. It has a quasi-experimental design. The sample included 93 students enrolled in Advanced Algebra courses at Calvin Christian High School in Grandville, MI. Four classes participated in a five-day unit that explored graphs of equalities and inequalities. Two classes used traditional graphing calculators and two classes used Geometer’s Sketchpad. One class of each type took a pretest to measure prior knowledge. All classes took a posttest and attitude survey at the end of the study. A t-test was used to compare class averages. There were no significant differences when looking at posttest and attitude survey results. There were significant differences when looking at difference scores from the pretest and posttest. This is an important result as it has implications on the use of technology in the mathematics classroom and in the formation of future studies like this one

The joy of gratifications: Promotion as a short-term boost or long-term success – The same for women and men?

Job satisfaction helps create a committed workforce with many positive effects, such as increased organisational citizenship behaviour and reduced absenteeism. In turn, job satisfaction can be increased through gratifications, such as wage increases and promotions. But human satisfaction is prone to being governed by the homeostatic principle and will eventually return to the individual's base level. Thus, we longitudinally examined the effects of promotions to managerial positions and pay raises on job satisfaction across a period of 27 years. Our analyses were based on a large-scale representative German panel (N = 5978 observations) that allowed us to separate the effect of a promotion from the effect of the corresponding wage increase. We found that promotions positively affected job satisfaction in the short term but diminished after 1 year. Furthermore, the influence of a promotion on job satisfaction was more pronounced for men than for women

Transitivity correlation:A descriptive measure of network transitivity

This paper proposes that common measures for network transitivity, based on the enumeration of transitive triples, do not reflect the theoretical statements about transitivity they aim to describe. These statements are often formulated as comparative conditional probabilities, but these are not directly reflected by simple functions of enumerations. We think that a better approach is obtained by considering the probability of a tie between two randomly drawn nodes, conditional on selected features of the network. Two measures of transitivity based on correlation coefficients between the existence of a tie and the existence, or the number, of two-paths between the nodes are developed, and called "Transitivity Phi" and "Transitivity Correlation." Some desirable properties for these measures are studied and compared to existing clustering coefficients, in both random (Erdos-Renyi) and in stylized networks (windmills). Furthermore, it is shown that in a directed graph, under the condition of zero Transitivity Correlation, the total number of transitive triples is determined by four underlying features: size, density, reciprocity, and the covariance between in- and outdegrees. Also, it is demonstrated that plotting conditional probability of ties, given the number of two-paths, provides valuable insights into empirical regularities and irregularities of transitivity patterns

An Equilibrium-Correction Model for Dynamic Network Data

We propose a two-stage MRQAP to analyze dynamic network data, within the framework of an equilibrium-correction (EC) model. Extensive simulation results indicate practical relevance of our method and its improvement over standard OLS. An empirical illustration additionally shows that the EC model yields interpretable parameters, in contrast to an unrestricted dynamic model

Dynamic Effects of Trust and Cognitive Social Structures on Information Transfer Relationships

Changes in relationships are due to human actions. We assume that these human actions are functions of perceptions of a focal individual, but also the perceptions of other individuals who are part of the organizational and social environment. We hypothesize that perceptions based trust and perceptions of the structural environment individuals operate in affect relationship change more than the "actual" environment in which individuals operate. An empirically analysis shows the dynamic effects of perceptions on changes in two types of relationships, which are believed to be important in account management. We explore, 1, whether the levels of perceptions, and, 2, whether changes in perceptions affect relationship changes. For example, we consider the effects of the amount of trust as well as the change in the amount of trust one individual puts in another individual. We find that perceptions have more impact on relationship change than "actual" network variables have. Furthermore, the results show that it is useful to distinguish between level and change effects of perceptions

Genetic and antigenic characterisation of serotype A FMD viruses from East Africa to select new vaccine strains

Vaccine strain selection for emerging foot-and-mouth disease virus (FMDV) outbreaks in enzootic countries can be addressed through antigenic and genetic characterisation of recently circulating viruses. A total of 56 serotype A FMDVs isolated between 1998 and 2012, from Central, East and North African countries were characterised antigenically by virus neutralisation test using antisera to three existing and four candidate vaccine strains and, genetically by characterising the full capsid sequence data. A Bayesian analysis of the capsid sequence data revealed the viruses to be of either African or Asian topotypes with subdivision of the African topotype viruses into four genotypes (Genotypes I, II, IV and VII). The existing vaccine strains were found to be least cross-reactive (good matches observed for only 5.4–46.4% of the sampled viruses). Three bovine antisera, raised against A-EA-2007, A-EA-1981 and A-EA-1984 viruses, exhibited broad cross-neutralisation, towards more than 85% of the circulating viruses. Of the three vaccines, A-EA-2007 was the best showing more than 90% in-vitro cross-protection, as well as being the most recent amongst the vaccine strains used in this study. It therefore appears antigenically suitable as a vaccine strain to be used in the region in FMD control programmes

Information Systems and Health Care-III: Diffusing Healthcare Knowledge: A Case Study of the Care Delivery Network

This article describes the experience of the Care Delivery Network as it promoted the successful diffusion of an innovative stroke treatment protocol across a wide range of healthcare institutions and practitioners in southeastern Ontario, Canada. The article is founded on research by Adler, Kwon, and Signer on knowledge management in professional communities. The Care Delivery Network case provides partial to strong empirical support for 17 Adler et al. research propositions. The article concludes with a summary of lessons learned and strategies for information and knowledge dissemination in professional settings

Budd-Chiari syndrome recurring in a transplanted liver

A patient with Budd-Chiari syndrome who underwent orthotopic liver transplantation and developed recurrent disease is described. The immediate postoperative period was complicated by multiple thrombotic episodes, followed by a period of apparent remission associated with the initiation of coumadin and persantine therapy. After discontinuation of such antithrombotic therapy in order to biopsy the liver, the patient experienced another series of clinically overt vascular thromboses and ultimately died of sepsis 15 mo posttransplantation after a prolonged and complicated terminal hospital course. At autopsy, recurrent Budd-Chiari syndrome as well as thromboses in numerous other organs was demonstrated. © 1983