931 research outputs found

    Transition Properties of Low Lying States in Atomic Indium

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    We present here the results of our relativistic many-body calculations of various properties of the first six low-lying excited states of indium. The calculations were performed using the relativistic coupled-cluster method in the framework of the singles, doubles and partial triples approximation. We obtain a large lifetime ~10s for the [4p^6]5s^2 5p_{3/2} state, which had not been known earlier. Our precise results could be used to shed light on the reliability of the lifetime measurements of the excited states of atomic indium that we have considered in the present work.Comment: 6 pages, 1 figure and 3 table

    Cellular automaton model of precipitation/dissolution coupled with solute transport

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    Precipitation/dissolution reactions coupled with solute transport are modelled as a cellular automaton in which solute molecules perform a random walk on a regular lattice and react according to a local probabilistic rule. Stationary solid particles dissolve with a certain probability and, provided solid is already present or the solution is saturated, solute particles have a probability to precipitate. In our simulation of the dissolution of a solid block inside uniformly flowing water we obtain solid precipitation downstream from the original solid edge, in contrast to the standard reaction-transport equations. The observed effect is the result of fluctuations in solute density and diminishes when we average over a larger ensemble. The additional precipitation of solid is accompanied by a substantial reduction in the relatively small solute concentration. The model is appropriate for the study of the r\^ole of intrinsic fluctuations in the presence of reaction thresholds and can be employed to investigate porosity changes associated with the carbonation of cement.Comment: LaTeX file, 13 pages. To appear in Journal of Statistical Physics (Proceedings of Lattice Gas'94, June 1994, Princeton). Figures available from author. Requests may be submitted by E-mail ([email protected]) or ordinary mail (Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland

    Greater fit and a greater gap: how environmental support for entrepreneurship increases the life satisfaction gap between entrepreneurs and employees

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    Purpose – This study seeks to understand how national institutional environments contribute to differences in life satisfaction between entrepreneurs and employees. Design/methodology/approach – Leveraging person–environment fit and institutional theories, and using a sample of more than 70,000 entrepreneurs and employees from 43 countries, the study investigates how the impact of entrepreneurial activity on life satisfaction differs in various environmental contexts. An entrepreneur’s life satisfaction arguably should increase when a high degree of compatibility or fit exists between his or her choice to be an entrepreneur and the informal and formal institutional environment. Findings – Differences in life satisfaction between entrepreneurs and employees are greater in countries marked by low individualism, high power distance, low uncertainty avoidance, supportive entrepreneurship policies, low commercial profit taxes, and weak worker rights. Originality/value – This study sheds new light on how entrepreneurial activity affects life satisfaction, contingent on the informal and formal institutions in a country that support entrepreneurship by its residents

    Advances in the Derivation of Northeast Siberian Forest Metrics Using High-Resolution UAV-Based Photogrammetric Point Clouds

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    Forest structure is a crucial component in the assessment of whether a forest is likely to act as a carbon sink under changing climate. Detailed 3D structural information about the tundra–taiga ecotone of Siberia is mostly missing and still underrepresented in current research due to the remoteness and restricted accessibility. Field based, high-resolution remote sensing can provide important knowledge for the understanding of vegetation properties and dynamics. In this study, we test the applicability of consumer-grade Unmanned Aerial Vehicles (UAVs) for rapid calculation of stand metrics in treeline forests. We reconstructed high-resolution photogrammetric point clouds and derived canopy height models for 10 study sites from NE Chukotka and SW Yakutia. Subsequently, we detected individual tree tops using a variable-window size local maximum filter and applied a marker-controlled watershed segmentation for the delineation of tree crowns. With this, we successfully detected 67.1% of the validation individuals. Simple linear regressions of observed and detected metrics show a better correlation (R2) and lower relative root mean square percentage error (RMSE%) for tree heights (mean R2 = 0.77, mean RMSE% = 18.46%) than for crown diameters (mean R2 = 0.46, mean RMSE% = 24.9%). The comparison between detected and observed tree height distributions revealed that our tree detection method was unable to representatively identify trees 15–20 m to capture homogeneous and representative forest stands. Additionally, we identify sources of omission and commission errors and give recommendations for their mitigation. In summary, the efficiency of the used method depends on the complexity of the forest’s stand structure

    Entrepreneurs' individual-level resources and social value creation goals : the moderating role of cultural context

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    Purpose—This study seeks to provide a better understanding of how the interplay of individual-level resources and culture affects entrepreneurs’ propensity to adopt social value creation goals. Design/methodology/approach—Using a sample of 12,685 entrepreneurs in 35 countries from the Global Entrepreneurship Monitor, this study investigates the main effects of individual-level resources—measured as financial, human, and social capital—on social value creation goals, as well as the moderating effects of the cultural context in which the respective entrepreneur is embedded, on the relationship between individual-level resources and social value creation goals. Findings—Drawing on the resource-based perspective and Hofstede’s cultural values framework, the results offer empirical evidence that individual-level resources are relevant for predicting the extent to which entrepreneurs emphasise social goals for their business. Furthermore, culture influences the way entrepreneurs allocate their resources toward social value creation. Originality/value—The study sheds new light on how entrepreneurs’ individual resources influence their willingness to create social value. Moreover, by focusing on the role of culture in the relationship between individual-level resources and social value creation goals, it contributes to social entrepreneurship literature, which has devoted little attention to the interplay of individual characteristics and culture
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