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In this paper we study the interaction between the estimation of the fractional differencing parameter d of ARFIMA models and the common practice of instantaneous transformation of the observed time series. At this aim, we first discuss the effect of a nonlinear transformation of the data on the identification of the process and on the estimate of d. Thus, we propose a joint estimation of the Box-Cox parameter and d by means of a modified normalized version of the Whittle likelihood. Then, the variance and covariance matrix of the parameters estimates is obtained. Finally, a Monte Carlo study is performed in order to check the behaviour of the proposed estimators in finite samples.The paper is the result of a joint research of the two authors. As far as it concerns this version of the work, A. DElia wrote Sects. 2, 3, 4, while D. Piccolo wrote Sects. 1, 5, 6. 相似文献
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A Multi‐level Dialectical–Paradox Lens for Top Management Team Strategic Decision‐Making in a Corporate Venture
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This paper aims to critique the process of corporate‐owned, high‐tech start‐up strategizing through an inductive, longitudinal, case study of ‘UK‐Research‐Tech’. Insights are given through the combined ‘dialectical–paradox’ concept, thereby focusing on where ‘dialectic’ and ‘paradox’ theorizing overlap. This linked iterative, ‘dialogical–dialectic’ research approach also reflects chief executive officer/top management team (CEO/TMT) start‐up dynamics over time. These foci fill important gaps that impede better understanding of dialectical, dialogical and paradoxical forces within strategic decision‐making. As an interpretative tool, they illuminate CEO/TMT strategizing and changing interrelationships affected by broader, volatile, techno‐economic contexts and parent‐company influences on ventures. In this case study, it was found that the CEO's relatively autocratic, parent‐framed approach combined with TMT members' contradictory reactions to create ‘dialectical–paradox’ oppositional forces, eventually only resolved through ‘eleventh hour’ business strategy changes to rescue the venture. This research contributes to more nuanced understandings of corporate‐constrained ventures during early business development from start‐up strategic decisions at parent‐company level to subsequent conditions of more independent dynamic equilibrium. The ‘dialectical–paradox’ conceptual lens contributes an innovative critique of processes affecting strategic decision‐making dynamics. Another important contribution is the empirically inspired conceptual model, developed for use both to guide subsequent case‐study research analyses and as a reflective tool for CEO/TMT strategic decision‐making, especially within corporate‐inspired start‐ups. 相似文献
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Zoccali R Muscatello MR Bruno A Serranò D Campolo D Pandolfo G Cedro C La Torre D Meduri M 《Journal of homosexuality》2008,55(2):265-273
Gender role is a multifactorial concept, as gender-related attitudes, behaviors, and personality are partially autonomous. The aim of the study was to evaluate the prevalent gender role identity in a sample of male homosexuals. One hundred male homosexuals and 50 male heterosexuals matched for age and sex, have been assessed with the Italian version of the Bem Sex-Role Inventory (BSRI; Bem, 1974). Statistically significant differences have been found between the two groups at the dimensions "Masculine" (z = 1.963; p = 0.001) and "Androgyny" (z = 2.367; p < 0.0001). The results obtained from the present study tend to confirm that homosexuals view themselves as adrogynous individuals, sharing both features of masculine and feminine gender roles. 相似文献
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The objective of this paper is to provide, for the first time, comparative estimates of racial residential segregation of blacks, Hispanics, and Native Americans in nonmetropolitan and metropolitan places in 1990 and 2000. Analyses are based on block data from the 1990 and 2000 U.S. decennial censuses. The results reveal a singularly important and perhaps surprising central conclusion: levels and trends in recent patterns of racial segregation in America's small towns are remarkably similar to patterns observed in larger metropolitan cities. Like their big-city counterparts, nonmetropolitan blacks are America's most highly segregated racial minority--roughly 30% to 40% higher than the indices observed for Hispanics and Native Americans. Finally, baseline ecological models of spatial patterns of rural segregation reveal estimates that largely support the conclusions reached in previous metropolitan studies. Racial residential segregation in rural places increases with growing minority percentage shares and is typically lower in "new" places (as measured by growth in the housing stock), while racially selective annexation and the implied "racial threat" at the periphery exacerbate racial segregation in rural places. Our study reinforces the need to broaden the spatial scale of segregation beyond its traditional focus on metropolitan cities or suburban places, especially as America's population shifts down the urban hierarchy into exurban places and small towns. 相似文献
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This article develops a new Markov-switching vector autoregressive (VAR) model with stochastic correlation for contagion analysis on financial markets. The correlation and the log-volatility dynamics are driven by two independent Markov chains, thus allowing for different effects such as volatility spill-overs and correlation shifts with various degrees of intensity. We outline a suitable Bayesian inference procedure based on Markov chain Monte Carlo algorithms. We then apply the model to some major and Asian-Pacific cross rates against the U.S. dollar and find strong evidence supporting the existence of contagion effects and correlation drops during crises, closely in line with the stylized facts outlined in the contagion literature. A comparison of this model with its closest competitors, such as a time-varying parameter VAR, reveals that our model has a better predictive ability. Supplementary materials for this article are available online 相似文献
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Fabio Crosilla Domenico Visintini Francesco Sepic 《Statistical Methods and Applications》2007,15(3):329-341
This paper proposes a statistical procedure for the automatic volumetric primitives classification and segmentation of 3D
objects surveyed with high density laser scanning range measurements. The procedure is carried out in three main phases: first,
a Taylor’s expansion nonparametric model is applied to study the differential local properties of the surface so to classify and identify homogeneous point
clusters. Classification is based on the study of the surface Gaussian and mean curvature, computed for each point from estimated differential parameters of the Taylor’s formula extended to second order
terms. The geometrical primitives are classified into the following basic types: elliptic, hyperbolic, parabolic and planar.
The last phase corresponds to a parametric regression applied to perform a robust segmentation of the various primitives. A Simultaneous AutoRegressive model is applied to define the trend surface for each geometric feature, and a Forward Search procedure puts in evidence outliers or clusters of non stationary data.
An erratum to this article can be found at 相似文献
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Domenico Parisi Diane K. McLaughlin Steven Michael Grice Michael Taquino Duane A. Gill 《Rural sociology》2003,68(4):491-512
Abstract A general criticism of the 1996 Welfare Reform Act is that it is primarily the result of an urban political agenda, and it may hurt rather than help the rural poor. Under the new welfare system, the rural poor that are most likely to be affected are those who live in socially, economically, and spatially disadvantaged communities. More residents in these communities are likely to need TANF, clients in these communities are least likely to leave TANF by finding employment, and community organizations are likely to have more limited resources to help TANF recipients. The objective of this study is to examine the extent to which variations in community conditions account for differences in TANF participation rates. Using 1997 TANF data from the Mississippi Department of Human Services, we estimated OLS regression models of local TANF participation rates across 100 communities in nonmetro counties. The results indicate that TANF participation rates tend to be higher in communities with high concentrations of African Americans, less faith‐based activeness, more employment in retail trade, spatial concentration of the poor, and located in the Delta. 相似文献
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