9,190 research outputs found

    Solutions of the Yang-Mills-Higgs equations in 2+1 dimensional anti-de Sitter space-time

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    The solutions of the Bogomolny equation in anti-de Sitter space-time are obtained by using Darboux transformations with both constant spectral parameters and variable "spectral parameters". These solutions give the Yang-Mills-Higgs fields in anti-de Sitter space-time. Some examples in SU(2) case are considered and qualitative asymptotic behaviors of the solutions as t tends to infinity are discussed in detail.Comment: LaTeX, 18 pages, 11 PS figure

    Intermediate-Mass Black Holes in Globular Clusters

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    There have been reports of possible detections of intermediate-mass black holes (IMBHs) in globular clusters (GCs). Empirically, there exists a tight correlation between the central supermassive black hole (SMBH) mass and the mean velocity dispersion of elliptical galaxies, "pseudobulges" and classical bulges of spiral galaxies. We explore such a possible correlation for IMBHs in spherical GCs. In our model of self-similar general polytropic quasi-static dynamic evolution of GCs, a criterion of forming an IMBH is proposed. The key result is M(BH) = L o^1/(1-n) where M(BH) is the IMBH mass, o is the GC mean stellar velocity, L is a coefficient, and 2/3 < n < 1

    Forecast on Energy Demand of Road Transportation in China

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    AbstractTo some extent, there are some uncertainties factors in forecasting energy demand of road transportation. Scientific forecasting China's energy demand of road transportation is a key for make long-term development plans of the nation's road transportation, and relevant policies of environmental protection and energy-saving. Basing on the energy demand of China's road transportation, considering the factors average fuel consumption of singleautomobile and the workload of road transportation, the paper does a comprehensive forecasting for China's energy demand of transportation in the future. The result is that in 2030, the energy demand of road transportation will amount to 250 million tons, which is 1.4 times that of 2020, and 2.3 times that of 2010. The significant increase of energy demand will inevitably bring great pressure to resources of energy and environmental protection, so the implementation of scientific development concept, saving resources and protecting the environment and adopting sustainable development policy will be the objective requirements for highway transportation development of China in the future

    Artificial Intelligence, CEO Turnover, and Directional Change in Firm Innovation

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    We examine the role of artificial intelligence (AI) in facilitating a change in innovation directions after a leadership change. Using patent data for firms that have gone through a CEO turnover, we find that firms with greater AI investment are more successful in changing their innovation directions. The effect of AI is driven principally by the continued development of innovation in areas that are modestly different from the past. Further analyses show that this effect is likely due to firms with AI investment that can enable strategic change in cultivating culture of exploring frontiers in innovation and managing R&D. A new CEO can direct more resources to the acquisition of employees with greater technological capabilities such as AI skills to facilitate the innovation change. Overall, our study sheds light on the value of AI in fostering the change in innovation directions during uncertain and turbulent times

    A Straightforward Path Routing in Wireless Ad Hoc Sensor Networks

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    Capacitance Characteristics of Pinus densata, Pinus tabuliformis, Pinus yunnanensis and the hybrids Pinus tabuliformis × Pinus Yunnanensis

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    We employed capacitance to evaluate the kinship and interspecific variation of homoploid hybrid conifer Pinus densata, P. tabuliformis, P. yunnanensis and artificial hybrids of P. tabuliformis (maternal parent) and P. yunnanensis (paternal parent) which were cultivated and selected in the common garden experiment. By measuring capacitance spectra under different voltage frequencies, we could differentiate different germplasms based on the electrical response. We aims to demonstrate that P. densata as the hybrid of P. tabuliformis and P. yunnanensis based on the capacitance values of the species, and to provide new evidence to the previously known biological evidence, as well as and the parental effect on the hybrids. Our results revealed that capacitance values between the species are significantly different in the spectra where P. yunnanensis positioned at the lowest and P. densata was much higher than all other species, indicating that P. densata had possessed a great capacity to store electrical energy. The capacitance spectra of P. densata and the artificial hybrid are not similar, which rejected our hypothesis. Both of the capacitance values of P. densata and the hybrids were closer to P. tabuliformis than to P. yunnanensis, which shows that the maternal influence was stronger than the paternal influence. Correlation analysis on the relationship between capacitance and fitnessrelated characteristics showed that capacitance is negatively correlated to mortality rate, and positively correlated with second-year survival rate. High capacitance values of P. densata and some of the hybrids reveal their superior adaptability to harsh environment in the Tibet Plateau. We concluded that capacitance as a new indicator for plant fitness and evolution evidence of homoploid hybrid conifers

    Joint distraction for knee osteoarthritis: protocol for a systematic review and meta-analysis

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    Background Osteoarthritis is a degenerative joint disease that is highly prevalent worldwide. Knee osteoarthritis is the most common form of osteoarthritis and is a major cause of pain and disability. However, there remains a lack of treatments available that have demonstrated effectiveness in stopping or reversing the degenerative process. Joint distraction has emerged as a viable alternative in the treatment of knee osteoarthritis to delay the need for knee arthroplasty. Methods An electronic search will be conducted on MEDLINE, EMBASE, Web of Science, CINAHL, Cochrane and EBSCO databases. Clinical studies investigating joint distraction for knee osteoarthritis, which reported clinical or structural outcomes including ∆WOMAC index, ∆VAS pain score and ∆joint space width will be included. Risk of bias will be assessed using the Newcastle-Ottawa Scale for observational studies and Cochrane Collaboration tool for randomised controlled trials. Quality of studies will be assessed using the modified Coleman methodology score. Discussion This systematic review will summarise the short- and long-term clinical and structural outcomes following joint distraction for knee osteoarthritis. The findings from this review will establish the quality of currently available evidence, which will determine the need for further studies to establish the true effect size of this procedure

    A multiple exp-function method for nonlinear differential equations and its application

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    A multiple exp-function method to exact multiple wave solutions of nonlinear partial differential equations is proposed. The method is oriented towards ease of use and capability of computer algebra systems, and provides a direct and systematical solution procedure which generalizes Hirota's perturbation scheme. With help of Maple, an application of the approach to the 3+13+1 dimensional potential-Yu-Toda-Sasa-Fukuyama equation yields exact explicit 1-wave and 2-wave and 3-wave solutions, which include 1-soliton, 2-soliton and 3-soliton type solutions. Two cases with specific values of the involved parameters are plotted for each of 2-wave and 3-wave solutions.Comment: 12 pages, 16 figure
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