1,948 research outputs found

    The Rich Get Richer: Enabling Conditions for Knowledge Use in Organizational Work Teams

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    Individuals on the periphery of organizational knowledge sharing networks, due to inexperience, location, or lack of social capital, may struggle to access useful knowledge at work. An electronic knowledge repository (KR) has the potential to help peripheral individuals gain access to valuable knowledge because a KR is universally and constantly available and can be used without social interaction. However, for it to serve this equalizing function, those on the periphery of the organization must actually use it, possibly overcoming barriers to doing so. In this paper, we develop a multi-level model of knowledge use in teams and show that individuals whose experience and position already provide them access to vital knowledge use a KR more frequently than individuals on the organizational periphery. We argue that this occurs because the KR – despite its appearance of equivalent accessibility to all – is actually more accessible to central than peripheral players due to their greater experience and access to colleagues. Thus, KR use is not driven primarily by the need to overcome limited access to other knowledge sources. Rather KR use is enabled when actors know how to reap value from the KR, which ironically improves with increasing access to other sources of knowledge. Implications for both team effectiveness and knowledge management research are offered. We conclude that KRs are unlikely to serve as a knowledge equalizer without intervention

    Integration of predictive routing information with dynamic traffic signal control

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.Includes bibliographical references (leaves 306-310).by Richard C. Staats.Ph.D

    Development of the cat-owner relationship scale (CORS)

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    Characteristics of the human-animal bond can be influenced by both owner-related and pet-related factors, which likely differ between species. Three studies adapted the Monash Dog-Owner Relationship Scale (MDORS) to permit assessment of human-cat interactions as perceived by the cat's owner. In Study 1293 female cat owners completed a modified version of the MDORS, where 'dog' was replaced with 'cat' for all items. Responses were compared with a matched sample of female dog owners. A partial least squares discriminant analysis revealed systematic differences between cat and dog owners in the Dog (Cat)-Owner Interaction subscale (MDORS subscale 1), but not for Perceived Emotional Closeness or Perceived Costs (Subscales 2 and 3). Study 2 involved analysis of free-text descriptions of cat-owner interactions provided by 61 female cat owners. Text mining identified key words which were used to create additional questions for a new Cat-Owner Interaction subscale. In Study 3, the resulting cat-owner relationship scale (CORS) was tested in a group of 570 cat owners. The main psychometric properties of the scale, including internal consistency and factor structure, were evaluated. We propose that this scale can be used to accurately assess owner perceptions of their relationship with their cat. A modified scale, combining items from the CORS and MDORS (a C/DORS), is also provided for when researchers would find it desirable to compare human-cat and human-dog interactions. (C) 2017 Elsevier B.V. All rights reserved

    Aesthetics and logistics in urban parks: can moving waste receptacles to park exits decrease littering?

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    In this paper we test two approaches to reduce littering in urban parks that potentially reinforce each other: Relocating waste receptacles and the presence of watching eyes. Moving waste receptacles from the interior to the exits of a park makes waste collection more efficient, but can have opposing effects: Decreased littering because of greater care inspired by the perception of natural beauty in a park without artifacts like waste receptacles, or increased littering because of the greater distance to waste receptacles. Preceded by an online study (N = 153), three successive field studies showed mixed evidence for increased littering when moving waste receptacles to the exits (Study 2 and 3). However, when additionally attaching pictures of watching animal eyes to trees in the park (Study 4), litter levels seemed to decrease. We conclude that littering is best countered with a combination of persuasive communication and physical measures.Social decision makin

    The contribution of type I interferon signaling to immunity induced by alphavirus replicon vaccines

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    The type I interferon (IFN) system is critical for protecting the mammalian host from numerous virus infections and plays a key role in shaping the anti-viral adaptive immune response. In this report, the importance of type I IFN signaling was assessed in a mouse model of alphavirus-induced humoral immune induction. Venezuelan equine encephalitis virus replicon particles (VRP) expressing the hemagglutinin (HA) gene from influenza virus (HA-VRP) were used to vaccinate both wildtype (wt) and IFN α/β receptor knockout (RKO) mice. HA-VRP vaccination induced equivalent levels of flu-specific systemic IgG, mucosal IgG, and systemic IgA antibodies in both wt and IFN RKO mice. In contrast, HA-VRP vaccination of IFN RKO mice failed to induce significant levels of flu-specific mucosal IgA antibodies at multiple mucosal surfaces. In the VRP adjuvant system, co-delivery of null VRP with ovalbumin (OVA) protein significantly increased the levels of OVA-specific serum IgG, fecal IgG, and fecal IgA antibodies in both wt and RKO mice, suggesting that type I IFN signaling plays a less significant role in the VRP adjuvant effect. Taken together, these results suggest that, 1) at least in regard to IFN signaling, the mechanisms which regulate VRP-induced immunity differ when VRP are utilized as expression vectors as opposed to adjuvants, and 2) type I IFN signaling is required for the induction of mucosal IgA antibodies directed against VRP-expressed antigen. These results potentially shed new light on the regulatory networks which promote immune induction, and specifically mucosal immune induction, with alphavirus vaccine vectors

    Selection of Reference Genes for Transcriptional Analysis of Edible Tubers of Potato (Solanum tuberosum L.)

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    Potato (Solanum tuberosum) yield has increased dramatically over the last 50 years and this has been achieved by a combination of improved agronomy and biotechnology efforts. Gene studies are taking place to improve new qualities and develop new cultivars. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) is a bench-marking analytical tool for gene expression analysis, but its accuracy is highly dependent on a reliable normalization strategy of an invariant reference genes. For this reason, the goal of this work was to select and validate reference genes for transcriptional analysis of edible tubers of potato. To do so, RT-qPCR primers were designed for ten genes with relatively stable expression in potato tubers as observed in RNA-Seq experiments. Primers were designed across exon boundaries to avoid genomic DNA contamination. Differences were observed in the ranking of candidate genes identified by geNorm, NormFinder and BestKeeper algorithms. The ranks determined by geNorm and NormFinder were very similar and for all samples the most stable candidates were C2, exocyst complex component sec3 (SEC3) and ATCUL3/ ATCUL3A/CUL3/CUL3A (CUL3A). According to BestKeeper, the importin alpha and ubiquitin-associated/ts-n genes were the most stable. Three genes were selected as reference genes for potato edible tubers in RT-qPCR studies. The first one, called C2, was selected in common by NormFinder and geNorm, the second one is SEC3, selected by NormFinder, and the third one is CUL3A, selected by geNorm. Appropriate reference genes identified in this work will help to improve the accuracy of gene expression quantification analyses by taking into account differences that may be observed in RNA quality or reverse transcription efficiency across the samples

    Issues in the Pharmacokinetics of Trichloroethylene and Its Metabolites

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    Much progress has been made in understanding the complex pharmacokinetics of trichloroethylene (TCE). Qualitatively, it is clear that TCE is metabolized to multiple metabolites either locally or into systemic circulation. Many of these metabolites are thought to have toxicologic importance. In addition, efforts to develop physiologically based pharmacokinetic (PBPK) models have led to a better quantitative assessment of the dosimetry of TCE and several of its metabolites. As part of a mini-monograph on key issues in the health risk assessment of TCE, this article is a review of a number of the current scientific issues in TCE pharmacokinetics and recent PBPK modeling efforts with a focus on literature published since 2000. Particular attention is paid to factors affecting PBPK modeling for application to risk assessment. Recent TCE PBPK modeling efforts, coupled with methodologic advances in characterizing uncertainty and variability, suggest that rigorous application of PBPK modeling to TCE risk assessment appears feasible at least for TCE and its major oxidative metabolites trichloroacetic acid and trichloroethanol. However, a number of basic structural hypotheses such as enterohepatic recirculation, plasma binding, and flow- or diffusion-limited treatment of tissue distribution require additional evaluation and analysis. Moreover, there are a number of metabolites of potential toxicologic interest, such as chloral, dichloroacetic acid, and those derived from glutathione conjugation, for which reliable pharmacokinetic data is sparse because of analytical difficulties or low concentrations in systemic circulation. It will be a challenge to develop reliable dosimetry for such cases

    Geometrical distribution of Cryptococcus neoformans mediates flower-like biofilm development

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    Microbial biofilms are highly structured and dynamic communities in which phenotypic diversification allows microorganisms to adapt to different environments under distinct conditions. The environmentally ubiquitous pathogen Cryptococcus neoformans colonizes many niches of the human body and implanted medical devices in the form of biofilms, an important virulence factor. A new approach was used to characterize the underlying geometrical distribution of C. neoformans cells during the adhesion stage of biofilm formation. Geometrical aspects of adhered cells were calculated from the Delaunay triangulation and Voronoi diagramobtained fromscanning electronmicroscopy images (SEM). A correlation between increased biofilm formation and higher ordering of the underlying cell distribution was found. Mature biofilm aggregates were analyzed by applying an adapted protocol developed for ultrastructure visualization of cryptococcal cells by SEM. Flower-like clusters consisting of cells embedded in a dense layer of extracellular matrix were observed as well as distinct levels of spatial organization: adhered cells, clusters of cells and community of clusters. The results add insights into yeast motility during the dispersion stage of biofilm formation. This study highlights the importance of cellular organization for biofilm growth and presents a novel application of the geometrical method of analysis

    Alphavirus replicon particles acting as adjuvants promote CD8+ T cell responses to co-delivered antigen

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    Alphavirus replicon particles induce strong antibody and CD8+ T cell responses to expressed antigens in numerous experimental systems. We have recently demonstrated that Venezuelan equine encephalitis virus replicon particles (VRP) possess adjuvant activity for systemic and mucosal antibody responses. In this report, we demonstrate that VRP induced an increased and balanced serum IgG subtype response to co-delivered antigen, with simultaneous induction of antigen-specific IgG1 and IgG2a antibodies, and increased both systemic and mucosal antigen-specific CD8+ T cell responses, as measured by an IFN-γ ELISPOT assay. Additionally, VRP further increased antigen-specific T cell immunity in an additive fashion following co-delivery with the TLR ligand, CpG DNA. VRP infection led to recruitment of CD8+ T cells into the mucosal compartment, possibly utilizing the mucosal homing receptor, as this integrin was upregulated on CD8+ T cells in the draining lymph node of VRP-infected animals, where VRP-infected dendritic cells reside. This newly recognized ability of VRP to mediate increased T cell response towards co-delivered antigen provides the potential to both define the molecular basis of alphavirus-induced immunity, and improve alphavirus-based vaccines
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