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171.
Under appropriate long range dependence conditions, the point process of exceedances of a stationary sequence weakly converges to a homogeneous compound Poisson point process. This limiting point process can be characterized by the extremal index and the cluster-size probabilities. In this paper we address the problem of estimating these quantities and we consider the intervals estimators introduced in Ferro and Segers [2003. Inference for clusters of extreme values. J. Roy. Statist. Soc. Ser. B 545–556] and in Ferro [2004. Statistical methods for clusters of extreme values. Ph.D. Thesis, Lancaster University]. We establish asymptotic weak convergence to Gaussian random variables and we give their asymptotic variance. 相似文献
172.
Daniela M. Witten Robert Tibshirani 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2009,71(3):615-636
Summary. We propose covariance-regularized regression, a family of methods for prediction in high dimensional settings that uses a shrunken estimate of the inverse covariance matrix of the features to achieve superior prediction. An estimate of the inverse covariance matrix is obtained by maximizing the log-likelihood of the data, under a multivariate normal model, subject to a penalty; it is then used to estimate coefficients for the regression of the response onto the features. We show that ridge regression, the lasso and the elastic net are special cases of covariance-regularized regression, and we demonstrate that certain previously unexplored forms of covariance-regularized regression can outperform existing methods in a range of situations. The covariance-regularized regression framework is extended to generalized linear models and linear discriminant analysis, and is used to analyse gene expression data sets with multiple class and survival outcomes. 相似文献
173.
Using confidential microdata from the US Census Bureau, we investigate the performance of Asian-owned businesses. Using regression
estimates and a special non-linear decomposition technique, we explore the role that class resources, such as financial capital
and human capital, play in contributing to the relative success of Asian businesses. We find that Asian-owned businesses are
more successful than white-owned businesses for two main reasons—Asian owners have high levels of human capital and their
businesses have substantial start-up capital. Using detailed information on both the owner and the firm, we estimate the explanatory
power of several additional factors.
相似文献
Robert W. Fairlie (Corresponding author)Email: |
174.
Robert D. Crutchfield Martie L. Skinner Kevin P. Haggerty Anne McGlynn Richard F. Catalano 《Race and social problems》2009,1(4):218-230
Criminologists have long reported the existence of racial disparity in the criminal justice system, but the important question
is why. While some argue that observed differences are a consequence of more criminal behavior among minorities, the weight
of the evidence indicates that this is but a partial explanation. In this paper, we study data from a sample of juveniles
to examine how racial differences in early police contact, and important social environments—family, school, and neighborhoods—affect
later contact and arrests, controlling for self-reported delinquency. We find that early (in middle school) contact with police
is an important predictor of later (high school) arrests. Also we found that, in addition to being male and living in a low-income
family, children who have parents who have a history of arrest, who have experienced school disciplinary actions, who have
delinquent peers, and who are in networks with deviant adults are more likely to have problems with law enforcement. These
factors help to explain racial differences in police contacts and arrests. 相似文献
175.
Is ethnic prejudice declining in Britain? Change in social distance attitudes among ethnic majority and minority Britons
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Most literature on racial prejudice deals with the racial attitudes of the ethnic majority and ethnic minorities separately. This paper breaks this tradition. We examine the social distance attitudes of white and non‐white British residents to test if these attitudes follow the same trends over time, whether they are driven by the same social processes and whether they are inter‐related. We have three main findings. Firstly, social distance from other ethnic groups has declined over time for both white and ethnic minority Britons. For the white majority there are both period and cohort elements to this decline. Secondly, we see some evidence that social distance between the majority and minority groups is reciprocal. Specifically, minorities who experience rejection by the white British feel a greater sense of distance from them. Thirdly, we find that all groups share the perception of the same ethnic hierarchy. We see evidence of particularly widespread hostility towards Muslim Britons from all ethnic groups suggesting that Muslims are singled out for negative attention from many British residents of all other backgrounds, including a large number who do not express hostility to other groups. 相似文献
176.
177.
Despite more than thirty years of debate, disagreement persists among research ethicists about the most appropriate way to interpret the U.S. regulations on pediatric research, specifically the categories of “minimal risk” and a “minor increase over minimal risk.” Focusing primarily on the definition of “minimal risk,” we argue in this article that the continued debate about the pediatric risk categories is at least partly because their conceptual status is seldom considered directly. Once this is done, it becomes clear that the most popular strategy for interpreting “minimal risk”—defining it as a specific set of risks—is indefensible and, from a pragmatic perspective, unlikely to resolve disagreement. Primarily this is because judgments about minimal risk are both normative and heavily intuitive in nature and thus cannot easily be captured by reductions to a given set of risks. We suggest instead that a more defensible approach to evaluating risk should incorporate room for reflection and deliberation. This dispositional, deliberative framework can nonetheless accommodate a number of intellectual resources for reducing reliance on sheer intuition and improving the quality of risk evaluations. 相似文献
178.
Jason D. P. Bird Michael C. LaSala Marco A. Hidalgo Lisa M. Kuhns Robert Garofalo 《Journal of homosexuality》2017,64(3):321-342
Young, gay, and bisexual men (YGBM) are at increased risk of family rejection, which is related to HIV infection. What remains unknown is how family rejection leads to HIV risk. In this exploratory study, qualitative interviews were conducted with 21 HIV-positive YGBM aged 18 to 24. Most participants reported family rejection, which decreased instrumental and emotional support and resulted in participants using riskier ways to support themselves, such as engaging in survival sex. Conceptualizing the findings using a family systems framework, we present a tentative conceptual model to describe the potential relationships between family rejection and HIV risk for YGBM. 相似文献
179.
Sandeep Mishra Martin L. Lalumière Robert J. Williams 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》2017,33(1):15-36
Research suggests that high frequency gambling is a component of the “generality of deviance”, which describes the observation that various forms of risky and antisocial behavior tend to co-occur among individuals. Furthermore, risky and antisocial behaviors have been associated with such personality traits as low self-control, and impulsivity, and sensation-seeking. We conducted a replication (and extension) of two previous studies examining whether high frequency gambling is part of the generality of deviance using a large and diverse community sample (n = 328). This study was conducted as a response to calls for more replication studies in the behavioral and psychological sciences (recent systematic efforts suggest that a significant proportion of psychology studies do not replicate). The results of the present study largely replicate those previously found, and in many cases, we observed stronger associations among measures of gambling, risk-taking, and antisocial behavior in this diverse sample. Together, this study provides evidence for the generality of deviance inclusive of gambling (and, some evidence for the replicability of research relating to gambling and individual differences). 相似文献
180.
Urbanization and other land cover changes have been particularly detrimental to wetlands throughout the planet. One wetland specialist that may be sensitive to land cover changes surrounding wetlands is the round-tailed muskrat (Neofiber alleni; hereafter RTM). The RTM is a wetland obligate rodent that appears to have declined over the last half century and is a species of concern in Florida, where it is a near endemic. To determine if urbanization or other land cover influenced the distribution of RTMs we took a multi-scaled approach to examine the occurrence of RTMs and their associated vegetation in North-Central Florida. We detected RTMs on 19 of 72 sample plots and used a Classification And Regression Tree (CART) to determine that dogfennel (Eupatorium capillifolium) was negatively associated with RTMs and maidencane (Panicum hemitomon) was positively associated with their occurrence on sampling plots. Examining the influence of landscape composition for 2 km surrounding our plots we found that RTM occurrence was negatively related to urban land cover. Further, we found that dogfennel increased and maidencane decreased as urbanization increased in the surrounding landscape. Our research suggests that conservation of RTMs and their associated vegetation should focus on limiting urban sprawl at least within 2 km of wetlands. 相似文献