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101.
An extended single‐index model is considered when responses are missing at random. A three‐step estimation procedure is developed to define an estimator for the single‐index parameter vector by a joint estimating equation. The proposed estimator is shown to be asymptotically normal. An algorithm for computing this estimator is proposed. This algorithm only involves one‐dimensional nonparametric smoothers, thereby avoiding the data sparsity problem caused by high model dimensionality. Some simulation studies are conducted to investigate the finite sample performances of the proposed estimators. 相似文献
102.
Outlier detection algorithms are intimately connected with robust statistics that down‐weight some observations to zero. We define a number of outlier detection algorithms related to the Huber‐skip and least trimmed squares estimators, including the one‐step Huber‐skip estimator and the forward search. Next, we review a recently developed asymptotic theory of these. Finally, we analyse the gauge, the fraction of wrongly detected outliers, for a number of outlier detection algorithms and establish an asymptotic normal and a Poisson theory for the gauge. 相似文献
103.
万历年间册立太子之争被称为"争国本",围绕册立皇长子朱常洛还是皇三子朱常洵,明神宗万历与廷臣进行了旷日持久的博弈。整个事件由廷臣温和的建议开始,经过长期而激烈的斗争,以至于谣言四起,最后借助太后的力量得以解决,按祖制皇长子朱常洵被册立为太子,皇三子朱常洛受封福王。争国本是认识明朝政治运作的典型样本,折射了专制王朝政治运作的内在逻辑。 相似文献
104.
A divergence of opinion: how those involved in child and family social work are responding to the challenges of the Internet and social media
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Jennifer E. Simpson 《Child & Family Social Work》2016,21(1):94-102
This discussion paper suggests that there is possibly a divergence of opinion taking place within the field of child and family social work and that the stated positions are influencing how practitioners identify and deal with risks and opportunities afforded by the Internet and social media. The suggested divergence is examined and the conclusion drawn is that what is taking place mirrors the fact that the introduction of any new technology inevitably brings with it division and debate. In seeking to understand the reaction to digital technology, consideration is given to a series of wider social discourses on childhood and risk, which includes the controversial notion that the profession is a harbinger of moral panic and that the management of risk has been broadened from child protection to child safety. The discussion paper concludes by calling for child and family social work practitioners to have a balanced debate that needs to be informed not only by current research but also by an open and honest discussion about personal use and an acknowledgement that there will be difficult moral and ethical questions to work through. 相似文献
105.
Dr. Yellman proposes to define frequency as “a time‐rate of events of a specified type over a particular time interval.” We review why no definition of frequency, including this one, can satisfy both of two conditions: (1) the definition should agree with the ordinary meaning of frequency, such as that less frequent events are less likely to occur than more frequent events, over any particular time interval for which the frequencies of both are defined; and (2) the definition should be applicable not only to exponentially distributed times between (or until) events, but also to some nonexponential (e.g., uniformly distributed) times. We make the simple point that no definition can satisfy (1) and (2) by showing that any definition that determines which of any two uniformly distributed times has the higher “frequency” (or that determines that they have the same “frequency,” if neither is higher) must assign a higher frequency number to the distribution with the lower probability of occurrence over some time intervals. Dr. Yellman's proposed phrase, “time‐rate of events … over a particular time interval” is profoundly ambiguous in such cases, as the instantaneous failure rates vary over an infinitely wide range (e.g., from one to infinity), making it unclear which value is denoted by the phrase “time‐rate of events.” 相似文献
106.
Self‐Construal,Career Decision Self‐Efficacy,and Perceived Barriers Predict Mexican American Women's Life Satisfaction
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Brandy Piña‐Watson Natalia Jimenez Lizette Ojeda 《The Career development quarterly》2014,62(3):210-223
This study used the social cognitive theory of well‐being (SCTW; Lent, 2004 ) to examine the role of career decision self‐efficacy (CDSE), perceived educational barriers, and independent self‐construal on the life satisfaction of 176 Mexican American college women. A 3‐step hierarchical regression analysis indicated that independent self‐construal, CDSE, and fewer perceived educational barriers significantly predicted greater life satisfaction among Mexican American college women above and beyond the influence of socioeconomic status and generational status. These findings are consistent with SCTW and highlight the need for counselors and researchers to be aware of the role that self‐construal, CDSE, and perceived educational barriers can have on Mexican American women's life satisfaction. Implications for practice at the secondary‐school and university levels are discussed. 相似文献
107.
摘要:针对砂泥岩互层的复杂测井环境,采用三维有限元数值模拟方法,计算了多层介质模型的水平井双侧向测井响应。结果表明,井眼半径、泥浆电阻率和围岩(砂岩、泥岩)的电阻率及侵入半径与电阻率对水平井双侧向测井响应都有不同程度的影响。在砂泥岩地层中,井眼尺寸越大,泥浆电阻率越高,对视电阻率的影响越严重;当目的层厚大于8 m 后,视电阻率受围岩(砂岩、泥岩)影响很小,基本上反映地层的真实电阻率,并且曲线变化规律大致相同,此时可近似为三层介质模型;对于低阻侵入,侵入越深,视电阻率越偏离真实地层电阻率。 相似文献
108.
Quantifying the Establishment Likelihood of Invasive Alien Species Introductions Through Ports with Application to Honeybees in Australia
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The cost of an uncontrolled incursion of invasive alien species (IAS) arising from undetected entry through ports can be substantial, and knowledge of port‐specific risks is needed to help allocate limited surveillance resources. Quantifying the establishment likelihood of such an incursion requires quantifying the ability of a species to enter, establish, and spread. Estimation of the approach rate of IAS into ports provides a measure of likelihood of entry. Data on the approach rate of IAS are typically sparse, and the combinations of risk factors relating to country of origin and port of arrival diverse. This presents challenges to making formal statistical inference on establishment likelihood. Here we demonstrate how these challenges can be overcome with judicious use of mixed‐effects models when estimating the incursion likelihood into Australia of the European (Apis mellifera) and Asian (A. cerana) honeybees, along with the invasive parasites of biosecurity concern they host (e.g., Varroa destructor). Our results demonstrate how skewed the establishment likelihood is, with one‐tenth of the ports accounting for 80% or more of the likelihood for both species. These results have been utilized by biosecurity agencies in the allocation of resources to the surveillance of maritime ports. 相似文献
109.
《Journal of Social Work Practice》2012,26(1):61-64
This article aims to stimulate discussion about relationships between the lives of professionals and of service users. The idea is that when parallels are explored and developed, power dynamics between professionals and social workers are reduced, the quality of interaction and work with service users can be improved, and professionals can also be helped in overcoming difficulties in their own lives. I start with an outline of my own personal background and highlight my development throughout, including my emerging identity as a Buddhist. I discuss a case study involving ‘Sally’ and her family and our work together while I was a social work assistant in a Children and Family's team. I try to show the interconnections between the different difficulties that we faced and how that informed my work. I look at some of the benefits, pitfalls and boundaries of working from the point of view that service user and professional are both working to overcome their problems. I also interweave interactions I had at the time with Carlos, a drug user friend in a crisis and the impact he had on me. Because I include my own situation I have called this article a ‘case experience’. Throughout I refer to Buddhist and psychoanalytic thinking and particularly to agreement between the two around ideas that inner‐resistance is the main barrier to personal evolution. I argue that faith is the key to unlocking resistance, and that faith should be understood as the development of a belief within people that they are able to progress rather than be destroyed in the face of inevitable problems. 相似文献
110.
NICOLAI BISSANTZ HOLGER DETTE KATHARINA PROKSCH 《Scandinavian Journal of Statistics》2012,39(2):305-322
Abstract. We consider the problem of testing parametric assumptions in an inverse regression model with a convolution‐type operator. An L 2 ‐type goodness‐of‐fit test is proposed which compares the distance between a parametric and a non‐parametric estimate of the regression function. Asymptotic normality of the corresponding test statistic is shown under the null hypothesis and under a general non‐parametric alternative with different rates of convergence in both cases. The feasibility of the proposed test is demonstrated by means of a small simulation study. In particular, the power of the test against certain types of alternative is investigated. Finally, an empirical example is provided, in which the proposed methods are applied to the determination of the shape of the luminosity profile of the elliptical galaxy NGC 5017. 相似文献