548 resultados para E. coli growth
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We outline a metal-free fabrication route of in-plane Ge nanowires on Ge(001) substrates. By positively exploiting the polishing-induced defects of standard-quality commercial Ge(001) wafers, micrometer-length wires are grown by physical vapor deposition in ultra-high-vacuum environment. The shape of the wires can be tailored by the epitaxial strain induced by subsequent Si deposition, determining a progressive transformation of the wires in SiGe faceted quantum dots. This shape transition is described by finite element simulations of continuous elasticity and gives hints on the equilibrium shape of nanocrystals in the presence of tensile epitaxial strain.
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This paper examines the effect of anisotropic growth on the evolution of mechanical stresses in a linear-elastic model of a growing, avascular tumour. This represents an important improvement on previous linear-elastic models of tissue growth since it has been shown recently that spatially-varying isotropic growth of linear-elastic tissues does not afford the necessary stress-relaxation for a steady-state stress distribution upon reaching a nutrient-regulated equilibrium size. Time-dependent numerical solutions are developed using a Lax-Wendroff scheme, which show the evolution of the tissue stress distributions over a period of growth until a steady-state is reached. These results are compared with the steady-state solutions predicted by the model equations, and key parameters influencing these steady-state distributions are identified. Recommendations for further extensions and applications of this model are proposed.
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Vascular endothelial growth factor (VEGF) promotes growth of blood or lymphatic vessels. The aim of the current study is to identify relationships between VEGF-A and VEGF-C, and their impact in angiogenesis and metastases in thyroid cancers. VEGF-A and VEGF-C mRNA and protein expression was investigated in 136 thyroid cancers (123 papillary thyroid carcinomas and 13 undifferentiated thyroid carcinomas) and 40 matched lymph node metastases with papillary thyroid carcinoma using reverse transcription polymerase chain reaction and immunohistochemistry. VEGF-A and VEGF-C mRNA expression was significantly different between conventional papillary thyroid carcinoma, follicular variant of papillary thyroid carcinoma, and undifferentiated thyroid carcinomas (P = 1 x 10(-6) and 1 x 10(-5), respectively). In undifferentiated carcinoma, VEGF-A and VEGF-C protein overexpression was noted in all cases. VEGF-A and VEGF-C mRNA overexpression was noted in 51% (n = 62) and 27% (n = 33) of the papillary thyroid carcinomas, whereas VEGF-A and VEGF-C protein overexpression was also identified in 70% (n = 86) and 62% (n = 76) of the carcinomas. VEGF-A mRNA was significantly higher in cancers with lymph node metastases compared with nonmetastatic cancers (P = .001), whereas most metastatic cancers underexpressed VEGF-C (P = .0002), with a similar trend for protein. The expression of VEGF-A and VEGF-C correlated with each other at both mRNA and protein levels (P = .00004 and .003, respectively). In summary, VEGF-A and -C expressions correlate with the pathological parameters and metastatic status of thyroid carcinomas. The significant correlations between the expressions of these genes add weight to hypotheses concerning VEGF-A and -C interaction in cancer progression.
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Background: Cancer metastasis is the main contributor to breast cancer fatalities as women with the metastatic disease have poorer survival outcomes than women with localised breast cancers. There is an urgent need to develop appropriate prognostic methods to stratify patients based on the propensities of their cancers to metastasise. The insulin-like growth factor (IGF)-I:IGF binding protein (IGFBP):vitronectin complexes have been shown to stimulate changes in gene expression favouring increased breast cancer cell survival and a migratory phenotype. We therefore investigated the prognostic potential of these IGF- and extracellular matrix (ECM) interaction-induced proteins in the early identification of breast cancers with a propensity to metastasise using patient-derived tissue microarrays. Methods: Semiquantitative immunohistochemistry analyses were performed to compare the extracellular and subcellular distribution of IGF- and ECM-induced signalling proteins among matched normal, primary cancer and metastatic cancer formalin-fixed paraffin-embedded breast tissue samples. Results: The IGF- and ECM-induced signalling proteins were differentially expressed between subcellular and extracellular localisations. Vitronectin and IGFBP-5 immunoreactivity was lower while β1 integrin immunoreactivity was higher in the stroma surrounding metastatic cancer tissues, as compared to normal breast and primary cancer stromal tissues. Similarly, immunoreactive stratifin was found to be increased in the stroma of primary as well as metastatic breast tissues. Immunoreactive fibronectin and β1 integrin was found to be highly expressed at the leading edge of tumours. Based on the immunoreactivity it was apparent that the cell signalling proteins AKT1 and ERK1/2 shuffled from the nucleus to the cytoplasm with tumour progression. Conclusion: This is the first in-depth, compartmentalised analysis of the distribution of IGF- and ECM-induced signalling proteins in metastatic breast cancers. This study has provided insights into the changing pattern of cellular localisation and expression of IGF- and ECM-induced signalling proteins in different stages of breast cancer. The differential distribution of these biomarkers could provide important prognostic and predictive indicators that may assist the clinical management of breast disease, namely in the early identification of cancers with a propensity to metastasise, and/or recur following adjuvant therapy.
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Description Through a combination of global data analysis and focused country level analysis, this timely book provides answers to the most pertinent country and industry specific questions defining the current relationship between technology, natural resources and economic growth. Contents Contents: Preface Part I: Global Analysis 1. Economic Growth and the Environment 2. Energy Substitution and Carbon Dioxide Emissions 3. Pollution, Natural Resources, and Economic Growth 4. Trade Openness and Environmental Quality 5. Environmental Productivity 6. Energy Price-induced Technological Change 7. Trade-induced Technological Change 8. Regional Economic Integration Part II: Country-Level Analysis 9. Emissions Trading in the United States 10. Increasing Returns to Pollution Abatement in the United States 11. Policy-induced Competitiveness in the United States 12. Trade Liberalization, Technology, and the Environment 13. Policy Implementation and its Effectiveness in China 14. Clean Technological Inventions in Japan 15. Intervention of Economic Policy and its Nonlinear Effects in Japan 16. The Next Emerging Giants: India and Africa 17. Conclusion Index Further information Through a combination of global data analysis and focused country level analysis, this timely book provides answers to the most pertinent country and industry specific questions defining the current relationship between technology, natural resources and economic growth. Shunsuke Managi takes a distinctive approach by focusing on the design and implementation of environmental regulations that encourage technological progress and, in doing so, looks at ways to ensure productivity improvements in the face of increasingly stringent environmental regulations and natural resource depletion. The findings in this important book demonstrate how successful environmental policies can contribute to efficiency by encouraging, rather than inhibiting, technological innovation. Technology, Natural Resources and Economic Growth will provide a valuable resource for a wide readership including postgraduate students, researchers, academics and policy makers working in the fields of environmental and ecological economics.
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The Environmental Kuznets Curve (EKC) hypothesises an inverse U-shaped relationship between a measure of environmental pollution and per capita income levels. In this study, we apply non-parametric estimation of local polynomial regression (local quadratic fitting) to allow more flexibility in local estimation. This study uses a larger and globally representative sample of many local and global pollutants and natural resources including Biological Oxygen Demand (BOD) emission, CO2 emission, CO2 damage, energy use, energy depletion, mineral depletion, improved water source, PM10, particulate emission damage, forest area and net forest depletion. Copyright © 2009 Inderscience Enterprises Ltd.
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While economic theory acknowledges that some features of technology (e.g., indivisibilities, economies of scale and specialization) can fundamentally violate the traditional convexity assumption, almost all empirical studies accept the convexity property on faith. In this contribution, we apply two alternative flexible production technologies to measure total factor productivity growth and test the significance of the convexity axiom using a nonparametric test of closeness between unknown distributions. Based on unique field level data on the petroleum industry, the empirical results reveal significant differences, indicating that this production technology is most likely non-convex. Furthermore, we also show the impact of convexity on answers to traditional convergence questions in the productivity growth literature.
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In this paper, the productivities of Japanese airports over the period of 1987-2005 are analyzed using the Malmquist index, and technological bias is investigated. During this period, airports on average became less efficient and experienced technological regress. Our results indicate that the traditional growth accounting method, which assumes Hicks neutral technological change, is not appropriate for analyzing changes in productivity for Japanese airports.
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This paper investigates the productivity change of Japanese credit banks with a Malmquist index and the input technological bias during 2000-2006. Our results indicate that the traditional growth accounting method, which assumes Hicks neutral technological change, is not appropriate for analyzing changes in productivity. Our analysis unambiguously shows that management of Shinkin banks has to be improved. These must be based on the improvement of technical efficiency and/or technological change, emulating the procedures of the best-practice banks, i.e., those banks with Malmquist productivity scores higher than one and simultaneously with technical efficiency and technological change higher than one.
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The relationship between small firm growth and HRM practices Rowena Barrett, Susan Mayson and Niel Warriner Introduction In this chapter we explore the relationship between small firms’ growth orientation, their business planning eorts and the role the owner plays and whether or not formal HRM practices are used. Formal HRM practices are assessed in terms of whether they are written down, regularly applied or assured to take place. We take on board Heneman et al.’s (2000) suggestion that ‘surveys of employer practices across SMEs [would] be [a] valuable addition to the strategic human resource management literature (p. 23) and report the results of an online and paper survey of a sample of 1753 small firms (dened as those employing less than 20 people) in the state of Victoria (SE Australia). Our particular interest in this chapter, which is based on an analysis of 410 responses to the survey, is whether growthoriented small firms adopt formal HRM practices. This research contributes to understanding whether more formal organizational systems and routines are more likely to be used (or not) to nurture human capital in growth-oriented small firms. Moreover by focusing on firm growth, this chapter, consistent with recent calls in the literature (see Baron, 2003; Barrett and Mayson, 2006; Katz et al., 2000; Tansky and Heneman, 2003), contributes to a better understanding of issues at the intersection of entrepreneurship and HRM research.
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Previous studies show that the Internet positively influences firms’ export activities from developed markets. However, the literature is vague as to whether the Internet has an impact on the export performance of firms from emerging markets. This study tests a conceptual model that includes the effect of Internet marketing capabilities on export market growth in an emerging market. Drawing on a cross-national sample of 204 export firms from a Latin American country (Chile), findings indicate that Internet marketing capabilities positively influence the availability of export information, which in turn impacts the development of business network relationships and export market growth.
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The effects of a range of different sublethal salinities were assessed on physiological processes and growth performance in the freshwater ‘tra’ catfish (Pangasianodon hypophthalmus) juveniles over an 8-week experiment. Fish were distributed randomly among 6 salinity treatments [2, 6, 10, 14 and 18 g/L of salinity and a control (0 g/L)] with a subsequent 13-day period of acclimation. Low salinity conditions from 2 to 10 g/L provided optimal conditions with high survival and good growth performance, while 0 g/L and salinities[14 g/L gave poorer survival rates (p\0.05). Salinity levels from freshwater to 10 g/L did not have any negative effects on fish weight gain, daily weight gain, or specific growth rate. Food conversion ratio, however, was lowest in the control treatment (p\0.05) and highest at the maximum salinities tested (18 g/L treatment). Cortisol levels were elevated in the 14 and 18 g/L treatments after 6 h and reached a peak after 24-h exposure, and this also led to increases in plasma glucose concentration. After 14 days, surviving fish in all treatments appeared to have acclimated to their respective conditions with cortisol levels remaining under 5 ng/ mL with glucose concentrations stable. Tra catfish do not appear to be efficient osmoregulators when salinity levels exceed 10 g/L, and at raised salinity levels, growth performance is compromised. In general, results of this study confirm that providing culture environments in the Mekong River Basin do not exceed 10 g/L salinity and that cultured tra catfish can continue to perform well.
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Should the firm move successfully into a growth or expansion phase the owner manager will be required to increase the scale and scope of its operations. Part of this expansion will involve hiring additional employees, and increasing the overall complexity of the firm's activities. It is likely that the need for greater levels of professional management will be required to operate the firm, along with the need for enhanced planning and the introduction of systems to support the new levels of complexity. The transition from a small, owner-managed firm to a large systems-managed business will require the development of a team-based management approach with greater specialisation within the management team. Corporate governance is also likely to change as the growth cycle takes place. As it grows, the business will become more formalised in its accounting, management and other systems. The need for greater quantities of capital is likely to lead the business towards equity finance. As new equity partner are taken into the company the original owner managers may find their level of control diminished. The larger the firm becomes the more likely its management structure will become decentralised with greater separation between the owner and the firm in terms of operational and financial matters.
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Traditional towns of the Kathmandu Valley boast a fine provision of public spaces in their neighbourhoods. Historically, a hierarchy of public space has been distributed over the entire town with each neighbourhood centered around more or less spacious public squares. However, rapid growth of these towns over the past decades has resulted in haphazard development of new urban areas with little provision of public space. Recent studies indicate that the loss of public space is a major consequence of the uncontrolled urban growth of the Kathmandu Valley and its new neighbourhoods. This paper reviews the current urban growth of the Kathmandu Valley and its impact on the development of public space in new neighbourhoods. The preliminary analysis of the case study of three new neighbourhoods shows that the formation and utilization of neighbourhood public space exhibit fundamental differences from those found in the traditional city cores. The following key issues are identified in this paper: a) Governance and regulations have been a challenge to regulate rapid urban growth; b) The current pattern of neighbourhood formation is found to be different from that of traditional neighbourhoods due to the changes with rapid urban development; c) Public spaces have been compromised in both planned and unplanned new neighbourhoods in terms of their quantity and quality; d) The changing provision of public space has contributed to its changing use and meaning; and e) The changing demographic composition, changing society and life style have had direct impact on the declining use of public space. Moreover, the management of public spaces remains a big challenge due to their changing nature and the changing governance. The current transformation public space does not appear to be conducive, and has led to adversely changing social environment of the new neighbourhoods.