3,097 research outputs found

    The Cultural Legacy of Communism in Entrepreneurship: Entrepreneurial Perceptions and Activity in Central and Eastern Europe

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    Using data from the Global Entrepreneurship Monitor, this paper examines differences in entrepreneurial perceptions (fear of failure, opportunity perception, self-efficacy, public opinion) between CEE and non-CEE countries, before and after the 2008 recession, as well as the effects of these perceptions on entrepreneurial motivation and overall levels of activity. The results suggest that CEE countries have systematically more pessimistic outlooks in terms of fear of failure and opportunity perception, but no difference from non-CEE countries in self-efficacy and public opinion. Additionally, most of the difference in fear of failure and opportunity perception, along with an increase in necessity-motivated entrepreneurship, comes after the recession, suggesting less durability and resilience of optimistic entrepreneurial perceptions in CEE countries. Finally, there is evidence of a higher threshold for a perceived opportunity to become a business reality in these post-socialist CEE countries

    Control Systems Approach to Balance Stabilization during Human Standing and Walking.

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    Humans rely on cooperation from multiple sensorimotor processes to navigate a complex world. Poor function of one or more components can lead to reduced mobility or increased risk of falls, particularly with age. At present, quantification and characterization of poor postural control typically focus on single sensors rather than the ensemble and lack methods to consider the overall function of sensors, body dynamics, and actuators. To address this gap, I propose a controls framework based on simple mechanistic models to characterize and understand normative postural behavior. The models employ a minimal set of components that typify human behavior and make quantitative predictions to be tested against human data. This framework is applied to four topics relevant to daily living: sensory integration for standing balance, limb coordination for one-legged balance, momentum usage in sit-to-stand maneuvers, and the energetic trade-offs of foot-to-ground clearance while walking. First, I demonstrate that integration of information from multiple physiological sensors can be modeled by an optimal state estimator. I show how such a model can predict human responses to conflict between visual, vestibular, and other sensors and use visual perturbation experiments to test this model. Second, I demonstrate that feedback control can model multi-limb coordination strategies during one-legged balance. I empirically identify a control law from human subjects and investigate how reducing stance ankle function necessitates greater gains from other limbs. Third, I show the advantages of momentum usage in sit-to-stand maneuvers. Counter to many human movements, this strategy is not performed with energetic economy, requiring excess mechanical work. However, with optimization models, I demonstrate that momentum serves to balance effort between knee and hip. Fourth, I propose a cost model for preferred ground clearance during swing phase of walking. Walking with greater foot lift is costly, but inadvertent ground contact is also costly. Therefore the tradeoff between these costly measures, modulated by movement variability, can explain expected cost of ground clearance. These controls-based models demonstrate the mechanisms behind normative behavior and enables predictions under novel situations. Thus these models may serve as diagnostic tools to identify poor postural control or aid design of intervention procedures.PhDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/116654/1/amyrwu_1.pd

    ‘May I speak Cantonese?’ – Co-constructing a scientific proof in an EFL junior secondary science classroom

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    In this paper, an excerpt of teacher–student interaction in an EFL junior secondary science classroom in Hong Kong is analysed using the conversation analytic method of sequential analysis. The fine-grained analysis reveals that in the teacher's effort to engage her students in the co-construction of a scientific proof, the students' familiar everyday discourses (e.g. students' examples and experiences as expressed in their familiar language) need to be allowed to play a significant role. It also shows how translanguaging can be well-coordinated with multimodal practices (using blackboard drawings, gestures) to facilitate students' meaning-making in the inquiry-based teacher–student dialogue.postprin

    The Biology of Climate Change: The effects of changing climate on migrating and over-wintering species at a high-elevation field station

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    Students engage with long-term environmental and phenology data sets (spanning over 40 years) collected at the Rocky Mountain Biological Laboratory, a high-elevation field station in Colorado, to explore the effects of climate change on the phenology of migrating and hibernating species. After becoming familiar with the geographic context, people involved with the data collection, and organisms studied through background readings and videos, students explore the raw data set in Excel or using an interactive data visualization tool. In small groups, students reproduce figures and regressions from Inouye et al. (2000) based on those data, then expand their analyses with data collected during the subsequent decade. By comparing analyses that encompass different time spans, students evaluate the original interpretations from Inouye et al. (2000), explain possible discrepancies, and generate predictions for future patterns. Finally, students build upon their initial analyses by developing and testing hypotheses about patterns found in other organisms in the data set, and combine these to discuss the ecological consequences of shifting plant and animal phenology in group presentations

    Biclustering random matrix partitions with an application to classification of forensic body fluids

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    Classification of unlabeled data is usually achieved by supervised learning from labeled samples. Although there exist many sophisticated supervised machine learning methods that can predict the missing labels with a high level of accuracy, they often lack the required transparency in situations where it is important to provide interpretable results and meaningful measures of confidence. Body fluid classification of forensic casework data is the case in point. We develop a new Biclustering Dirichlet Process (BDP), with a three-level hierarchy of clustering, and a model-based approach to classification which adapts to block structure in the data matrix. As the class labels of some observations are missing, the number of rows in the data matrix for each class is unknown. The BDP handles this and extends existing biclustering methods by simultaneously biclustering multiple matrices each having a randomly variable number of rows. We demonstrate our method by applying it to the motivating problem, which is the classification of body fluids based on mRNA profiles taken from crime scenes. The analyses of casework-like data show that our method is interpretable and produces well-calibrated posterior probabilities. Our model can be more generally applied to other types of data with a similar structure to the forensic data.Comment: 45 pages, 10 figure
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