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11.
目的对胶质母细胞瘤内部PTEN基因突变以及Ki-67表达情况进行研究,并对两者关系展开探讨。方法取胶质瘤石蜡切片102例为研究对象,其中胶质母细胞瘤切片42例,对所选样本行聚合酶链反应-单链构象多态性处理分析(PCR-SSCP),对其PTEN基因突变进行检测;并对Ki-67在胶质瘤中的表达行免疫组化SP检测法进行检测。结果在胶质母细胞瘤中,PTEN基因突变发生率与剩余60例相比明显更高(P〈0.05);在Ki-67平均标记指数方面,胶质母细胞瘤与其它胶质瘤相比数值更高(P〈0.05)。结论在胶质母细胞瘤中,PTEN基因突变对其发生以及发展具有重要作用;其病理恶性程度则与Ki-67表达程度呈明显的正相关;Ki-67表达程度同PTEN基因突变之间的关系也表现为正相关。 相似文献
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Recent financial turmoil (e.g., the 2008–2009 global financial crisis) has resulted in financial contagion-induced instability becoming one of the major concerns in the fields of economics and finance. In this paper, we extend the network analysis of financial contagion from three perspectives. First, given that cross-holding of claims and obligations among financial institutions can be viewed as input-output linkages, we model the financial system and the contagion mechanism by introducing the classic Leontief input–output framework. Second, based on this modeling process, we propose a simple contagion algorithm to study how financial system heterogeneity influences its stability. Third, to mitigate financial contagion, we propose several concrete intervention policies based on two widely used prudential approaches—forced mergers and capital injections. The performance of these intervention policies is then evaluated by comprehensive numerical experiments. Our study has significant implications for financial regulation and supervision. 相似文献
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Ikuo KUROIWA 《The Developing economies》2009,47(2):147-176
Rules of origin are an integral part of all trade rules. To be eligible for Common Effective Preferential Tariffs under the ASEAN Free Trade Area (AFTA) agreement, a product must satisfy the conditions relative to value content. The present paper seeks to calculate value content of industries in Southeast Asia, using the formula specified by the rules of origin in AFTA, the ASEAN–China FTA, the ASEAN–Korea FTA, and the ASEAN–Japan FTA. Moreover, the paper attempts to calculate true value content of industries by applying a simple technique of input–output analysis, and to estimate error margins (i.e., overestimates) in calculating value content. The paper also examines the relationship between value content and production networks. The paper finds that many industries exhibited declines in local content during the period 1990–2000, but that the geographical spread of production networks raised the proportion of inputs supplied by the neighboring ASEAN countries, so that the contribution of the cumulative rule of origin increased. 相似文献
14.
Jock Given 《Australian economic history review》2017,57(2):158-193
This article analyses the evolution of multinational enterprise through a case study of the Australasian wireless company, AWA, in the first half of the twentieth century. Ownership, location, and internalisation advantages explain aspects of the industry's rapid internationalisation, but other factors, including restrictive domestic legislation and oligopolistic competition, are also important. The imperialism of the era encouraged globalisation while binding companies to host nations' strategic imperatives and coordinated policy frameworks. Location factors included government desires to control wireless, especially once broadcasting developed in the 1920s, and to expand local manufacturing capacity for the emerging consumer electrical economy. 相似文献
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《Telecommunications Policy》2022,46(7):102332
The aim of this paper is to present a quantification approach for the calculation of the ICT sector's structural effects in the economy, focusing on the case of Greece. We construct a composite sector using a hypothetical extraction methodology based on the most recent Greek input-output table and structural business statistics at the national level. Our framework builds on the formal definition of the ICT sector provided by OECD and includes two distinct sub-components, ICT manufacturing and ICT services. In the second stage of this study, we explore the production linkages among ICT services, ICT manufacturing and the rest of the Greek industries using input-output-based and network analysis-based metrics that build on the intermediate transactions of an expanded input-output table of the Greek economy that includes the two sectors. Our empirical findings suggest that the total ICT sector has a major contribution to the Greek economy in terms of GDP and employment, but this is driven mainly by the ICT services component. We further identify that ICT services are more integrated in the Greek production network compared to ICT manufacturing, but their production linkages are underperforming in terms of meaningful contribution to the activity of the rest of the sectors. These results reflect the low integration of digital technologies and can be further embedded in a discussion on the ICT deficiencies of the Greek economy and the need for targeted regulatory and financial interventions. 相似文献
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During the 1980's, extensive structural adjustments took place in the U.S. economy. This paper uses estimates of sectorally detailed social accounting matrices to evaluate the changes in receipt and expenditure patterns, including interindustry linkages, over the 1982–1988 period. Among other effects, our results reveal increasing service orientation, shifts in energy use, and increased import and foreign investment dependence. Detailed evidence on direct and indirect demand linkages indicates large shifts in the composition of government expenditure and private investment, the latter being intensified by declines in the rate of domestic capital formation.We would like to thank Greg Alward for the 1982 IMPLAN input-output data, Norman Bakka for the National Income and Product Account Data, Ken Hanson for helpful suggestions, Mark Planting for 1985 BEA input-output data, Valerie Personick for the activity output data, and two anonymous referees for helpful comments. 相似文献
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We re‐interpret the drivers of structural change in Australia from Federation to World War II. Manufacturing increased its relative share of output and employment, the farm sector and mining contracted. Conventional wisdom contends these shifts largely resulted from government policy, particularly increases in trade barriers. We contend that the connection between tariffs and increased profitability is conceptually weak and not supported by extant evidence. We argue that exogenous shifts in consumer preferences, the adoption of new technologies, changing factor proportions, and greater specialisation in manufacturing and services were responsible for manufacturing increasing its share of the economy's resources and output. 相似文献
19.
Tao Li Jiaming Liu He Zhu Shuying Zhang 《Asia Pacific Journal of Tourism Research》2018,23(6):549-559
The booming rural tourism (RT) has broadened ways for rural revitalization and poverty alleviation strategy in China. Rural tourism enterprises (RTEs), as the core operator and a hinge delivering its benefits to rural communities, play a critical role in the achievement of RT expectation on rural revitalization. To address the research gap in business characteristics and efficiency of RTEs, and make the theoretical contribution to rural business and tourism management, this study collected and analyzed the business data with investors or managers of 60 national-class RTEs in Jiangsu Province, north Yangtze River Delta of China. The results showed that business characteristics of RTEs varied with their property, business strategy, and rural industrial base. Flexible and sustainable business operation and comprehensive regional development have a profound influence on business efficiency that presented multi spatial disparity from inter-regional and intra-regional views, respectively. In addition, the political and practical implications on rural business and RTEs for research and practice were also discussed. 相似文献
20.
We study the problem of testing hypotheses on the parameters of one- and two-factor stochastic volatility models (SV), allowing for the possible presence of non-regularities such as singular moment conditions and unidentified parameters, which can lead to non-standard asymptotic distributions. We focus on the development of simulation-based exact procedures–whose level can be controlled in finite samples–as well as on large-sample procedures which remain valid under non-regular conditions. We consider Wald-type, score-type and likelihood-ratio-type tests based on a simple moment estimator, which can be easily simulated. We also propose a C(α)-type test which is very easy to implement and exhibits relatively good size and power properties. Besides usual linear restrictions on the SV model coefficients, the problems studied include testing homoskedasticity against a SV alternative (which involves singular moment conditions under the null hypothesis) and testing the null hypothesis of one factor driving the dynamics of the volatility process against two factors (which raises identification difficulties). Three ways of implementing the tests based on alternative statistics are compared: asymptotic critical values (when available), a local Monte Carlo (or parametric bootstrap) test procedure, and a maximized Monte Carlo (MMC) procedure. The size and power properties of the proposed tests are examined in a simulation experiment. The results indicate that the C(α)-based tests (built upon the simple moment estimator available in closed form) have good size and power properties for regular hypotheses, while Monte Carlo tests are much more reliable than those based on asymptotic critical values. Further, in cases where the parametric bootstrap appears to fail (for example, in the presence of identification problems), the MMC procedure easily controls the level of the tests. Moreover, MMC-based tests exhibit relatively good power performance despite the conservative feature of the procedure. Finally, we present an application to a time series of returns on the Standard and Poor’s Composite Price Index. 相似文献