A comparison of various methods for estimating the parameters in mixtures of von mises distributions

In this paper we compare five methods for estimating the unknown parameters in a mixture of two von Mises distributions. We propose a new method based on the characteristic function and compare it with the classical methods based on maximum likelihood and moments. Thus far these methods have been successfully applied only to linear data. Here we show that the application to circular data is reasonably straightforward and that convergence to the final estimates is fairly rapid. For various simulated known mixtures the results obtained are satisfactory. Finally, we introduce a modification of the method of moments which is considerably faster in CPU time than any of the other methods used and gives good results.     

The exact solution to the mle of a decreasing density based on arbitrarily right censored data

Nonparametric maximum likelihood estimation of decreasing and unimodal density functions, based on observations subject to arbitrary right censorship, was considered by McNichols and Padgett(1982). In order to compute their estimators, however, nonlinear equations with linear constraints had to be maximized using numerical techniques. The exact solution to this problem can now be found. An example illustrates the simplicity of the method.     

An emplrical bayes approach in estimating the parameters of the or more geometric distributions

The estimation of the parameters of two or more geometric distribuionsis considered by usinq an empirical Bayesian approach. Robbins (1983) gave empirical Bayes estimates if the number of distributions N is large, buthere we consider the cascwhore N is small. The parameters of the prior distribution areest imated by looking at maximum like lihood and momentest imation methods.     

Accounting for unsafe sex: Interviews with men who have sex with men

Semi‐structured one‐on‐one interviews with 102 gay and bisexual men were conducted to examine the reasoning processes men use to exempt themselves from practicing safe sex. Qualitative analysis of the interviews revealed the following recurring themes: (a) Many men who were in couple relationships avoided condom use for reasons involving intimacy or trust, or because both partners were HIV‐negative; (b) unsafe sex sometimes occurred inadvertently or involuntarily; (c) negative moods and self‐images were associated with unsafe sex; (d) by “intuiting” that their partner was HIV‐negative, participants exempted themselves from the need for safe sex; and (e) when the boundary between safe and unsafe was unclear, participants used a combination of unofficial and official guidelines to determine what is safe.     

Continuing Competence and Relicensure

Abstract

The purpose of licensing laws is to provide assurance of high quality service and to protect the public from incompetent practitioners. Safeguarding entrance to the professions by licensing examinations is one part of this responsibility which is entrusted to the professional boards. Assuring the continuing competence of practicing professionals is another part and a major challenge to every board of nursing throughout the United States.

A 1979 mail survey identified 18 states which have specific continuing education requirements for relicensure of nurses. In addition, three states have standards of practice incorporated in the rules and regulations governing the nursing profession.

Mandatory continuing education is a first step in the implementation of a system to assure the public of the continuing competency for practice of the professional nurse. It is acknowledgement, with the force of law, that continuous renewal of knowledge is a necessary condition for assuring competence. However, it is not sufficient in itself. Knowledge must be integrated in performance, which is the final test of competency. Thus, other system components that assure continuing competency must be developed and implemented. These include the identification of standards of acceptable performance, and the development and implementation of measures to evaluate practicing professionals and assure that they meet the performance standards. These measures include peer review, self-assessment, and recertification procedures. Successful implementation of a complete effective system will require the collaborative efforts of practicing nurses, their professional organizations, and the state boards of nursing.     

Evaluation of the Service Review Model With Performance Scorecards

The current study combined a management technique termed “Service Review” with performance scorecards to enhance staff and consumer behavior in a human service setting consisting of 11 supervisors and 56 front-line staff working with 9 adult consumers with challenging behaviors. Results of our intervention showed that service review and scorecards produced significant staff behavior changes that were maintained over time. Positive consumer outcomes were also correlated with staff performance changes. The behavioral package of training, clinical consultation, service review, biweekly manager meetings, scorecards, and public posting has the potential to reduce the need for monetary staff incentives.     

Binge Drinking Among Undergraduate College Students in the United States: Implications for Other Substance Use

Abstract

The authors examined the relationship between binge drinking and other substance use among US college students, using nationally representative data from the 1995 National College Health Risk Behavior Survey implemented by the Centers for Disease Control and Prevention. Compared with nonbinge drinkers, current binge drinkers were significantly more likely to report “ever” using and current use of cigarettes, marijuana, cocaine, and other illegal drugs. The researchers also found that the more often students binge drank, the more likely they were to have ever used cigarettes, marijuana, cocaine, and other drugs, and the more likely they were to report current use of cigarettes and marijuana. Those who design programs to prevent binge drinking and use of other substances should take into account the reality that many students use more than one substance and that the more frequently students report binge drinking, the more likely they are to be using other substances as well.     

Innovations in teaching social work research

This article reviews the innovations in teaching research in social work education, including conceptual material and specific examples. There is attention to the ideological differences inherent in research and its instruction, methodology/technology innovations, and integrative and group approaches, among other developments. Examination of three major models of research instruction and their assumptions about the purpose of research in social work is presented. Discussion about ethical codes and curricular guidelines for social work programs in the United States and the United Kingdom provides a framework to understand the importance of teaching and learning research for the social work profession.     

结构助词“的”的使用规律

对结构助词“的”的使用规律。从句子、语义、语用三个平面加以考察。“的”的取舍对句法、语义结构关系产生影响时，必须用“的”；对句法、语义结构的改变没有影响时，“的”的取舍由语用上的需要决定。“的”的取舍在句法、语义规则上具有强制性，在语用规则上具有选择性。