Two-stage hierarchical modeling for analysis of subpopulations in conditional distributions

In this work, we develop modeling and estimation approach for the analysis of cross-sectional clustered data with multimodal conditional distributions where the main interest is in analysis of subpopulations. It is proposed to model such data in a hierarchical model with conditional distributions viewed as finite mixtures of normal components. With a large number of observations in the lowest level clusters, a two-stage estimation approach is used. In the first stage, the normal mixture parameters in each lowest level cluster are estimated using robust methods. Robust alternatives to the maximum likelihood estimation are used to provide stable results even for data with conditional distributions such that their components may not quite meet normality assumptions. Then the lowest level cluster-specific means and standard deviations are modeled in a mixed effects model in the second stage. A small simulation study was conducted to compare performance of finite normal mixture population parameter estimates based on robust and maximum likelihood estimation in stage 1. The proposed modeling approach is illustrated through the analysis of mice tendon fibril diameters data. Analyses results address genotype differences between corresponding components in the mixtures and demonstrate advantages of robust estimation in stage 1.     

Low dose risk estimation via simultaneous statistical inferences

Summary.  The paper develops and studies simultaneous confidence bounds that are useful for making low dose inferences in quantitative risk analysis. Application is intended for risk assessment studies where human, animal or ecological data are used to set safe low dose levels of a toxic agent, but where study information is limited to high dose levels of the agent. Methods are derived for estimating simultaneous, one-sided, upper confidence limits on risk for end points measured on a continuous scale. From the simultaneous confidence bounds, lower confidence limits on the dose that is associated with a particular risk (often referred to as a bench-mark dose ) are calculated. An important feature of the simultaneous construction is that any inferences that are based on inverting the simultaneous confidence bounds apply automatically to inverse bounds on the bench-mark dose.     

从狩猎到献祭:希腊葬礼仪式剖析

史前史和民族学领域的学者认为,在初民社会中,死人和死去的动物有着同等的对待,因为都是处理死亡,这就决定了葬礼仪式跟狩猎仪式有着某种必然的联系。事实上,从一开始,狩猎和献祭仪式就伴随着葬礼仪式且相互影响。本文论述葬礼仪式的发生以及葬礼过程中的种种仪式行为,如动物献祭、仪式性杀戮、仪式食物的分享、对尸体的处理等。通过具体诠释,表明神话观念对仪式行为的支配性作用,葬礼仪式在确认和维系社会群体持续性中的重要作用。     

African American family life in societal context: Crisis and hope

Since 1965 hundreds of articles and books have been published about African American families. Nevertheless, our understanding of these families continues to be limited. There is a tendency to gloss over important within-group differences; thus, monolithic, stereotypic and inaccurance portrayals of Black family life are common. This paper sets aside debates of Black family pathology or viability, focusing instead on these families' essential character. The paper seeks to understand Black families on their own terms, locating them in relevant social, historical, political and cultural contexts. Key empirical patterns and trends reveal dramatic changes in Black family geographic location, headship, quality of life and socioeconomic status since 1950.A complex picture is revealed. There has been gradual but steady overall improvement alongside persistent, extreme racial disparties and pronounced class disparities among Black families. The proposed Black Family Socio-Ecological Context model specifies and connects institutional, interpersonal, environmental, temporal and cultural facts that shape the essential character of Black family life in such a way as to produce characteristics simultaneously shared and idiosyncratic. The model also provides an organized, systematic accounting of research and public policy issues relevant to the study of African American families.An early version co-authored with Richard A. English was presented during the National Council on Family Relations Meetings in Portland, Oregon, October 1980.     

Brown rats (<Emphasis Type=Italic>Rattus norvegicus</Emphasis>) in urban ecosystems: are the constraints related to fieldwork a limit to their study?

Nowadays, the majority of human beings live in urban ecosystems, with this proportion expected to continue increasing in the future. With the growing importance of urban rat-associated issues (e.g. damages to urban infrastructures, costs of rat-control programs, rat-associated health risks), it is becoming indispensable to fill the identified gaps in knowledge on the urban brown rat regarding, among others, its density, home range, genetic structure, and infectious status. In this context, live-trapping is a crucial prerequisite to any scientific investigation. This paper assesses the main constraints and challenges regarding the urban field and describes the major steps to be considered when planning research on urban rats. The primary challenges are i) the characterization of the urban experimental unit; ii) the choice of a trapping design: the use of live-trapping in capture-mark-recapture design, in association with modern statistics, is highly recommended to answer ecological questions (although these methods, mostly developed in natural ecosystems, need to be implemented for the urban field); iii) the potential ethical considerations with regard to animal welfare and field-worker safety; iv) the building of mutually-beneficial collaborations with city stakeholders, pest control professionals, and citizens. Emphasis must be put on communication to the public and education of field-workers. One major need of modern urban rat research is a peer-validated field methodology allowing reproducibility, repeatability, and inference from urban field studies and enabling researchers to answer long-standing key questions about urban rat ecology.     

The FARSEEING real-world fall repository: a large-scale collaborative database to collect and share sensor signals from real-world falls

Background

Real-world fall events objectively measured by body-worn sensors can improve the understanding of fall events in older people. However, these events are rare and hence challenging to capture. Therefore, the FARSEEING (FAll Repository for the design of Smart and sElf-adaptive Environments prolonging Independent livinG) consortium and associated partners started to build up a meta-database of real-world falls.

Results

Between January 2012 and December 2015 more than 300 real-world fall events have been recorded. This is currently the largest collection of real-world fall data recorded with inertial sensors. A signal processing and fall verification procedure has been developed and applied to the data. Since the end of 2015, 208 verified real-world fall events are available for analyses. The fall events have been recorded within several studies, with different methods, and in different populations. All sensor signals include at least accelerometer measurements and 58 % additionally include gyroscope and magnetometer measurements. The collection of data is ongoing and open to further partners contributing with fall signals. The FARSEEING consortium also aims to share the collected real-world falls data with other researchers on request.

Conclusions

The FARSEEING meta-database will help to improve the understanding of falls and enable new approaches in fall risk assessment, fall prevention, and fall detection in both aging and disease.

     

Evidence-based practice: a critical reflection

This article employs the process of critical reflection to uncover and challenge the hegemonic assumptions of evidence-based practice (EBP). The critical reflection process results in a re-conceptualisation of best practices that, while still honouring empirical research, is less hierarchical and more inclusive of a broad spectrum of interests than traditional EBP. Multidimensional Evidence-Based Practice (MEBP) validates consumer wisdom, professional experience, and qualitative research as equal partners to quantitative research in determining current state-of-the art best practices. Furthermore, MEBP incorporates a value-critical analysis of those best practices that can lead to improvements and innovations, so that ‘best practices’ becomes a dynamic rather than a static construct.     

Dynamic Measures of Individual Deprivation

We introduce a one-parameter class of individual deprivation measures. Motivated by a suggestion of Runciman, we modify Yitzhaki’s index by multiplying it by a function that is interpreted as measuring the part of deprivation generated by an agent’s observation that others in his reference group move on to a higher level of income than himself. The parameter reflects the relative weight given to these dynamic considerations, and the standard Yitzhaki index is obtained as a special case. In addition, we characterize more general classes of measures that pay attention to this important dynamic aspect of deprivation.