Growth of Incumbent Firms and Entrepreneurship in Vietnam

This paper analyzes the relationship between the performance of incumbent firms and the net entry of new firms by combining different theoretical views of entrepreneurship. It shows that new knowledge and ideas created but not commercialized by incumbents are an important source of entrepreneurial opportunities for nascent firms. Different regression models to treat dynamics and endogeneity issues are applied to test the research hypothesis that growth of incumbent firms in a region will stimulate start-up activities by creating new profit opportunities for potential entrepreneurs. Vietnam’s regional micro-data from 2000 to 2008 are used for this test. Four controlling indicators – entrepreneurial demand, market structure, regional economic environment, and market innovativeness – are found to exert a statistically significant effect on new entries.

The Interplay of Human and Social Capital in Shaping Entrepreneurial Performance: The Case of Vietnam

This study investigates the effects of human capital, social capital and their interaction on the performance of 1,398 Vietnamese new-born firms. Operating profit is used as the measure of success. Human capital is captured by individual-level professional education, start-up experience, and learning. Whereas the first two dimensions of human capital are measured with traditional indicators, we define learning as ability to accumulate knowledge to conduct innovation activities (new product introduction, product innovation and process innovation). Social capital is measured as benefits obtained from personal strong-tie and weak-tie networks. Key findings are three-fold: (i) human capital strongly predicts firm success, with learning exerting a statistically significant positive impact on operating profit; (ii) benefits from weak ties outweigh those from strong ties; (iii) interaction of human capital and social capital displays a statistically significant positive effect on new-firm performance.

Co-doping red-emitting Sr2Si5N8:Eu2+ into yellow-emitting phosphor-packaging for enhancing the optical properties of the 8500 K remote-phosphor packaging wleds

In the last decades, WLEDs attract more and more consideration in both academic and industrial purposes because of its advantages such as fast response time, environment friendliness, small size, long lifetime, and high efficiency. In this research, by doping the red-emitting Sr2Si5N8:Eu2+ phosphor particles into yellow-emitting YAG:Ce phosphor-packaging, a new recommendation for enhancing the optical properties (color uniformity, color rendering index, and lumen output) of the 8500 K remote-phosphor packaging WLEDs is presented, investigated, and demonstrated. By using Mat Lab and Light Tools software based on Mie Theory, the obtained results show that the optical properties of the 8500 K remote-phosphor packaging WLEDs significantly depended on Sr2Si5N8:Eu2+ concentration. The results have provided a potential practical recommendation for manufacturing remote-phosphor W-LEDs.Web of Science1341034102

Well-Rounded ideal lattices of cyclic cubic and quartic fields

In this paper, we find criteria for when cyclic cubic and cyclic quartic fields have well-rounded ideal lattices. We show that every cyclic cubic field has at least one well-rounded ideal. We also prove that there exist families of cyclic quartic fields which have well-rounded ideals and explicitly construct their minimal bases. In addition, for a given prime number $p$, if a cyclic quartic field has a unique prime ideal above $p$, then we provide the necessary and sufficient conditions for that ideal to be well-rounded. Moreover, in cyclic quartic fields, we provide the prime decomposition of all odd prime numbers and construct an explicit integral basis for every prime ideal.Comment: 26 page

Well-Rounded Twists of Ideal Lattices from Imaginary Quadratic Fields

In this paper, we investigate the properties of well-rounded twists of a given ideal lattice of an imaginary quadratic field $K$. We show that every ideal lattice $I$ of $K$ has at least one well-rounded twist lattice. Moreover, we provide an explicit algorithm to compute all well-rounded twists of $I$.Comment: 24 page

Novel steady state of a microtubule assembly in a confined geometry

We study the steady state of an assembly of microtubules in a confined volume, analogous to the situation inside a cell where the cell boundary forms a natural barrier to growth. We show that the dynamical equations for growing and shrinking microtubules predict the existence of two steady states, with either exponentially decaying or exponentially increasing distribution of microtubule lengths. We identify the regimes in parameter space corresponding to these steady states. In the latter case, the apparent catastrophe frequency near the boundary was found to be significantly larger than that in the interior. Both the exponential distribution of lengths and the increase in the catastrophe frequency near the cell margin is in excellent agreement with recent experimental observations.Comment: 8 pages, submitted to Phys. Rev.