871 research outputs found

    Antecedents and consequences of effectuation and causation in the international new venture creation process

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    The selection of the entry mode in an international market is of key importance for the venture. A process-based perspective on entry mode selection can add to the International Business and International Entrepreneurship literature. Framing the international market entry as an entrepreneurial process, this paper analyzes the antecedents and consequences of causation and effectuation in the entry mode selection. For the analysis, regression-based techniques were used on a sample of 65 gazelles. The results indicate that experienced entrepreneurs tend to apply effectuation rather than causation, while uncertainty does not have a systematic influence. Entrepreneurs using causation-based international new venture creation processes tend to engage in export-type entry modes, while effectuation-based international new venture creation processes do not predetermine the entry mod

    Free abdominal fluid without obvious solid organ injury upon CT imaging: an actual problem or simply over-diagnosing?

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    Whereas a non-operative approach for hemodynamically stable patients with free intraabdominal fluid in the presence of solid organ injury is generally accepted, the presence of free fluid in the abdomen without evidence of solid organ injury not only presents a challenge for the treating emergency physician but also for the surgeon in charge. Despite recent advances in imaging modalities, with multi-detector computed tomography (CT) (with or without contrast agent) usually the imaging method of choice, diagnosis and interpretation of the results remains difficult. While some studies conclude that CT is highly accurate and relatively specific at diagnosing mesenteric and hollow viscus injury, others studies deem CT to be unreliable. These differences may in part be due to the experience and the interpretation of the radiologist and/or the treating physician or surgeon

    Regulation of signal duration and the statistical dynamics of kinase activation by scaffold proteins

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    Scaffolding proteins that direct the assembly of multiple kinases into a spatially localized signaling complex are often essential for the maintenance of an appropriate biological response. Although scaffolds are widely believed to have dramatic effects on the dynamics of signal propagation, the mechanisms that underlie these consequences are not well understood. Here, Monte Carlo simulations of a model kinase cascade are used to investigate how the temporal characteristics of signaling cascades can be influenced by the presence of scaffold proteins. Specifically, we examine the effects of spatially localizing kinase components on a scaffold on signaling dynamics. The simulations indicate that a major effect that scaffolds exert on the dynamics of cell signaling is to control how the activation of protein kinases is distributed over time. Scaffolds can influence the timing of kinase activation by allowing for kinases to become activated over a broad range of times, thus allowing for signaling at both early and late times. Scaffold concentrations that result in optimal signal amplitude also result in the broadest distributions of times over which kinases are activated. These calculations provide insights into one mechanism that describes how the duration of a signal can potentially be regulated in a scaffold mediated protein kinase cascade. Our results illustrate another complexity in the broad array of control properties that emerge from the physical effects of spatially localizing components of kinase cascades on scaffold proteins.Comment: 12 pages, 6 figure

    A global analysis of the comparability of winter chill models for fruit and nut trees

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    Many fruit and nut trees must fulfill a chilling requirement to break their winter dormancy and resume normal growth in spring. Several models exist for quantifying winter chill, and growers and researchers often tacitly assume that the choice of model is not important and estimates of species chilling requirements are valid across growing regions. To test this assumption, Safe Winter Chill (the amount of winter chill that is exceeded in 90% of years) was calculated for 5,078 weather stations around the world, using the Dynamic Model [in Chill Portions (CP)], the Chilling Hours (CH) Model and the Utah Model [Utah Chill Units (UCU)]. Distributions of the ratios between different winter chill metrics were mapped on a global scale. These ratios should be constant if the models were strictly proportional. Ratios between winter chill metrics varied substantially, with the CH/CP ratio ranging between 0 and 34, the UCU/CP ratio between −155 and +20 and the UCU/CH ratio between −10 and +5. The models are thus not proportional, and chilling requirements determined in a given location may not be valid elsewhere. The Utah Model produced negative winter chill totals in many Subtropical regions, where it does not seem to be useful. Mean annual temperature and daily temperature range influenced all winter chill ratios, but explained only between 12 and 27% of the variation. Data on chilling requirements should always be amended with information on the location and experimental conditions of the study in which they were determined, ideally including site-specific conversion factors between winter chill models. This would greatly facilitate the transfer of such information across growing regions, and help prepare growers for the impact of climate change

    Mastery, perceived stress and health-related behaviour in northeast Arnhem Land: a cross-sectional study

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    BACKGROUND: Indigenous peoples in Australia are disadvantaged on all markers of health and social status across the life course. Psychosocial factors are implicated in the aetiology of chronic diseases and in pathways underpinning social health disparities. Minimal research has investigated psychosocial factors and health in Indigenous peoples. This study evaluated associations between mastery, perceived stress, and health-related behaviour for a remote Indigenous population in Australia. METHODS: Complete data on mastery (the degree to which individuals feel in control of their lives), perceived stress, physical activity, and fruit and vegetable consumption were obtained for 177 participants in a community-based chronic disease risk factor survey. Psychosocial questionnaires were completed as an option during community screening (response rate = 61.9%). Extensive consultation facilitated the cross-cultural adaptation of measures. RESULTS: Mastery was inversely correlated with perceived stress measures (p < 0.009): recent stress, r = -0.47; chronic stress, r = -0.41; and youth stress, r = -0.30. Relationships between mastery and behaviour varied according to age group (<25 or ≥25 years) for physical activity (p = 0.001) and vegetable consumption (p = 0.005). Individuals aged ≥25 years engaging in ≤2 bouts of physical activity/week had lower mastery than individuals engaging in ≥3 bouts/week, with means (95% CI) of 14.8 (13.7–15.8) and 17.1 (15.3–19.0), respectively (p = 0.026). Individuals aged ≥25 years eating vegetables ≤3 times/week had lower mastery than those eating vegetables ≥4 times/week (p = 0.009) [means 14.7 (13.8–15.5) and 17.3 (15.5–19.1), respectively]. Individuals <25 years engaging in ≤2 bouts of physical activity/week had greater mastery than individuals engaging in ≥3 bouts/week (p = 0.022) [means 17.2 (15.2–19.2) and 13.8 (11.9–15.7), respectively]. For men ≥25 years and women ≥15 years, mastery was inversely related to age (p < 0.002). Men <25 years had less mastery than women of equivalent age (p = 0.001) [means 13.4 (12.1–14.7) and 17.5 (15.3–19.8), respectively]. CONCLUSION: Consistent with previous research, this study provides additional support for a link between mastery and health-related behaviour, and extends evidence of this association to a remote Indigenous population. Mastery's association with perceived stress, its age-specific association with health behaviour, and findings of low mastery amongst young men, highlights a need for life course research accounting for contextual factors affecting Indigenous peoples
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