678 research outputs found
Branching patterns in phylogenies cannot distinguish diversity-dependent diversification from time-dependent diversification
One of the primary goals of macroevolutionary biology has been to explain general trends in longâterm diversity patterns, including whether such patterns correspond to an upscaling of processes occurring at lower scales. Reconstructed phylogenies often show decelerated lineage accumulation over time. This pattern has often been interpreted as the result of diversityâdependent (DD) diversification, where the accumulation of species causes diversification to decrease through niche filling. However, other processes can also produce such a slowdown, including time dependence without diversity dependence. To test whether phylogenetic branching patterns can be used to distinguish these two mechanisms, we formulated a timeâdependent, but diversityâindependent model that matches the expected diversity through time of a DD model. We simulated phylogenies under each model and studied how well likelihood methods could recover the true diversification mode. Standard model selection criteria always recovered diversity dependence, even when it was not present. We correct for this bias by using a bootstrap method and find that neither model is decisively supported. This implies that the branching pattern of reconstructed trees contains insufficient information to detect the presence or absence of diversity dependence. We advocate that tests encompassing additional data, for example, traits or range distributions, are needed to evaluate how diversity drives macroevolutionary trends
The Hugging Team: The Role of Technology in Business Networking Practices
Abstract. Technological devices for social networking are produced in droves and networking through media seems to be the way of getting ahead in business. We examine what role technology plays in the creation, development and maintenance of business relationships among entrepreneurs in Copenhagen. We find that mediated communication is useful in all stages of relational maintenance but only in a supportive role in relational development where co-presence and shared personal experiences take center-stage, generating trust necessary for business relationships to work. These trust-developing experiences take effort and hard work and although they can be successfully supported and even facilitated through the use of communication technologies, they need not be replaced or made simpler. The difficulties of creating these experiences make working business relationships viable in the uncertain and risky world of entrepreneurship
Virtual Team Leader Communication:Employee Perception and Organizational Reality
Based on a study of leader communication effectiveness conducted in a large human resource outsourcing firm, this article reports how virtual team membersâ perceptions of their leadersâ effective use of communication tools and techniques affect team performance outcomes. The study also investigates the role that trust plays in moderating the relationship between virtual team membersâ perceptions of their leadersâ effective use of communication and team performance. Analysis of 458 responses from 68 teams found a positive relationship between virtual team membersâ perceptions of leadersâ effective use of communications and team membersâ perception of their teamâs performance. The study also found that trust strengthens the relationship between perceived leader communication effectiveness and team performance results. Last, the study also revealed serious organizational alignment issues between what team members perceived to be effective leader communication, their perception of team performance outcomes, and the organizations performance measured by a balanced scorecard
Multidimensional Facets of Perceived Risk in Mobile Travel Booking
Despite the growing prevalence of smartphones in daily life and travel context, travellers still perceive an extent of risk associated with using their smartphone to book travel products. In order to alleviate or reduce perceived risk, it is important to better understand the dimensions of and the factors that contribute to perceived risk. This study analysed 411 responses from an online panel to examine perceived risk in mobile travel booking and identified the following facets: time risk, financial risk, performance risk, privacy/security risk, psychological risk, physical risk, and device risk. Several antecedents of perceived risk were identified. Perceived collection of personal information via smartphones contributes positively, while consumer innovativeness, trust, and visibility contribute negatively to perceived risk. Further, the predictive validity of perceived risk is confirmed as it significantly explains perceived usefulness, attitude, and behavioural intention in mobile travel booking. Implications to manage perceived risk and its antecedents are provided
E-government adoption: A cultural comparison
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ Springer Science + Business Media, LLC 2008.E-government diffusion is an international phenomenon. This study compares e-government adoption in the U.K. to adoption in the U.S. In particular, this study seeks to determine if the same factors are salient in both countries. Several studies have explored citizen acceptance of e-government services in the U.S. However, few studies have explored this phenomenon in the U.K. To identify the similarities and differences between the U.K. and the U.S. a survey is conducted in the U.K. and the findings are compared to the literature that investigates diffusion in the U.S. This study proposes a model of e-government adoption in the U.K. based on salient factors in the U.S. A survey is administered to 260 citizens in London to assess the importance of relative advantage, trust and the digital divide on intention to use e-government. The results of binary logistic regression indicate that there are cultural differences in e-government adoption in the U.K. and the U.S. The results indicate that of the prevailing adoption constructs, relative advantage and trust are pertinent in both the U.S. and the U.K., while ICT adoption barriers such as access and skill may vary by culture. Implications for research and practice are discussed
Threat or treat for tourism organizations? The Copenhagen zoo social media storm
Social media have emerged as a game changer for tourism by empowering consumers to collectively approve or oppose organizational behaviors. When consumers rise against organizations, social media storms (SMSs) can be an outcome. This research proposes a conceptual framework to help tourism organizations understand SMSs and to guide more effective decision making. Contextualized by a case study of the Copenhagen Zoo, it is shown how and why SMSs are an expression of negative consumer empowerment that brings challenges as well as opportunities. As demonstrated, an SMS can lead to a helix for value creation for the organization, consumers, and society
Visualisation of trust and quality information for geospatial dataset selection and use:Drawing trust presentation comparisons with B2C e-Commerce
The evaluation of geospatial data quality and trustworthiness presents a major challenge to geospatial data users when making a dataset selection decision. Part of the problem arises from the inconsistent and patchy nature of data quality information, which makes intercomparison very difficult. Over recent years, the production and availability of geospatial data has significantly increased, facilitated by the recent explosion of Web-based catalogues, portals, standards and services, and by initiatives such as INSPIRE and GEOSS. Despite this significant growth in availability of geospatial data and the fact that geospatial datasets can, in many respects, be considered commercial products that are available for purchase online, consumer trust has to date received relatively little attention in the GIS domain. In this paper, we discuss how concepts of trust, trust models, and trust indicators (largely derived from B2C e-Commerce) apply to the GIS domain and to geospatial data selection and use. Our research aim is to support data users in more efficient and effective geospatial dataset selection on the basis of quality, trustworthiness and fitness for purpose. To achieve this, we propose a GEO label â a decision support mechanism that visually summarises availability of key geospatial data informational aspects. We also present a Web service that was developed to support generation of dynamic GEO label representations for datasets by combining producer metadata (from standard catalogues or other published locations) with structured user feedback
Early suppression of immune response pathways characterizes children with prediabetes in genome-wide gene expression profiling
Type 1 diabetes (T1D) is caused by autoimmune destruction of insulin-producing pancreatic p cells in the islets of Langerhans. Although defects in various T cell subsets have been linked to the disease pathogenesis, mechanisms initiating or enhancing the autoimmunity in prediabetes remain poorly understood. To unravel genes and molecular pathways affected by the diabetes-associated autoimmunity, we investigated transcriptomic profiles of prospective whole-blood samples from children who have developed T1D-associated autoantibodies and eventually clinical T1D. Gene-level investigation of the data showed systematic differential expression of 520 probesets. A network-based analysis revealed then a highly significant down-regulated network of genes involved in antigen presentation as well as T-cell receptor and insulin signaling. Finally, detection of dynamic changes in the affected pathways at the early or late phases of autoimmunity showed down-regulation of several novel T1D-associated pathways as well as known key components of immune response. The longitudinal genome-wide data generated in the present study allows the detection of dynamic changes relevant to the disease that may be completely missed in conventional cross-sectional studies or in genome-wide association studies. Taken together, our analysis showed systemic high-level repression of immune response pathways associated with T1D autoimmunity. (C) 2010 Elsevier Ltd. All rights reserved.</p
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