Local influence in seemingly unrelated regression model with ridge estimate

Local influence is a well-known method for identifying the influential observations in a dataset and commonly needed in a statistical analysis. In this paper, we study the local influence on the parameters of interest in the seemingly unrelated regression model with ridge estimation, when there exists collinearity among the explanatory variables. We examine two types of perturbation schemes to identify influential observations: the perturbation of variance and the perturbation of individual explanatory variables. Finally, the efficacy of our proposed method is illustrated by analyzing [13 A. Munnell, Why has productivity declined? Productivity and public investment, New Engl. Econ. Rev. (1990), pp. 3–22. [Google Scholar]] productivity dataset.     

Does the road to muscle rejuvenation go through Notch?

The capacity of skeletal muscles to repair and regenerate declines during aging in humans, and this decline may lead to muscle loss and frailty. Conboy et al. show that injured muscles of aging mice are defective in Notch signaling, because up-regulation of the Notch ligand, Delta-1, is impaired. Delta-1 promotes proliferation of the satellite cells that repair damaged muscles, and Conboy et al. show that experimental activation of Notch signaling is sufficient to reverse the age-related decline in muscle regenerative capacity. Extension of these important findings to humans could lead to the development of new therapeutic approaches to maintain muscle function during aging.     

Bayesian hierarchical regression models for detecting QTLs in plant experiments

Quantitative trait loci (QTL) mapping is a growing field in statistical genetics. In plants, QTL detection experiments often feature replicates or clones within a specific genetic line. In this work, a Bayesian hierarchical regression model is applied to simulated QTL data and to a dataset from the Arabidopsis thaliana plants for locating the QTL mapping associated with cotyledon opening. A conditional model search strategy based on Bayesian model averaging is utilized to reduce the computational burden.     

Children's Expression of Emotional Meaning in Music Through Expressive Body Movement

Recent research has demonstrated that preschool children can decode emotional meaning in expressive body movement; however, to date, no research has considered preschool children's ability to encode emotional meaning in this media. The current study investigated 4- (N = 23) and 5- (N = 24) year-old children's ability to encode the emotional meaning of an accompanying music segment by moving a teddy bear using previously modeled expressive movements to indicate one of four target emotions (happiness, sadness, anger, or fear). Adult judges visually categorized the silent videotaped expressive movement performances by children of both ages with greater than chance level accuracy. In addition, accuracy in categorizing the emotion being expressed varied as a function of age of child and emotion. A subsequent cue analysis revealed that children as young as 4 years old were systematically varying their expressive movements with respect to force, rotation, shifts in movement pattern, tempo, and upward movement in the process of emotional communication. The theoretical significance of such encoding ability is discussed with respect to children's nonverbal skills and the communication of emotion.     

Landscape,vegetation characteristics,and group identity in an urban and suburban watershed: why the 60s matter

As highly managed ecosystems, urban areas should reflect the social characteristics of their managers, who are primarily residents. Since landscape features develop over time, we hypothesize that present-day vegetation should also reflect social characteristics of past residents. Using an urban-to-suburban watershed in the Baltimore Metropolitan Region, this paper examines the relationship between demographics, housing characteristics, and lifestyle clusters from 1960 and 2000 with areas of high woody and herbaceous vegetation cover in 1999. We find that 1960 demographics and age of housing are better predictors of high woody or tree coverage in 1999 than demographics and housing characteristics from 2000. Key variables from 1960 are percent in professional occupations (+), percent of pre-WWI housing (−), percent of post-WWII housing (+), and population density (−). Past and present demographic and housing variables are poor predictors of high herbaceous cover in 1999. Lifestyle clusters for 2000 are very good predictors of high herbaceous coverage in 1999, but lifestyle clusters from 1960 and 2000 are poor predictors of high woody vegetation coverage. These findings suggest that herbaceous or grassy areas, typically lawns, are good reflections of contemporary lifestyle characteristics of residents while neighborhoods with heavy tree canopies have largely inherited the preferred landscapes of past residents and communities. Biological growth time scales of trees and woody vegetation means that such vegetation may outlast the original inhabitants who designed, purchased, and planted them. The landscapes we see today are therefore legacies of past consumption patterns.     

NUSAP Method for Evaluating the Data Quality in a Quantitative Microbial Risk Assessment Model for Salmonella in the Pork Production Chain

The numeral unit spread assessment pedigree (NUSAP) system was implemented to evaluate the quality of input parameters in a quantitative microbial risk assessment (QMRA) model for Salmonella spp. in minced pork meat. The input parameters were grouped according to four successive exposure pathways: (1) primary production (2) transport, holding, and slaughterhouse, (3) postprocessing, distribution, and storage, and (4) preparation and consumption. An inventory of 101 potential input parameters was used for building the QMRA model. The characteristics of each parameter were defined using a standardized procedure to assess (1) the source of information, (2) the sampling methodology and sample size, and (3) the distributional properties of the estimate. Each parameter was scored by a panel of experts using a pedigree matrix containing four criteria (proxy, empirical basis, method, and validation) to assess the quality, and this was graphically represented by means of kite diagrams. The parameters obtained significantly lower scores for the validation criterion as compared with the other criteria. Overall strengths of parameters related to the primary production module were significantly stronger compared to the other modules (the transport, holding, and slaughterhouse module, the processing, distribution, and storage module, and the preparation and consumption module). The pedigree assessment contributed to select 20 parameters, which were subsequently introduced in the QMRA model. The NUSAP methodology and kite diagrams are objective tools to discuss and visualize the quality of the parameters in a structured way. These two tools can be used in the selection procedure of input parameters for a QMRA, and can lead to a more transparent quality assurance in the QMRA.     

Fictions and Facts about Parents and Parenting Older First-Time Entrants to Foster Care

Knowledge about the parents of older first-time entrants into foster care is embedded in fictions created by media images, anecdotal stories of professionals in the child welfare system, as well as reports and observations of youths who have experienced foster care. Even though there are caring and effective nonrelatives who are foster parents, the public perception of non-relative foster parents is sometimes quite negative. In order to separate some of the facts from some of the fictions about the parents/caregivers of older first-time entrants to foster care, this article will describe the parents and relative caregivers (grandparents and others) of older first-time entrants to foster care in an urban public welfare agency by examining maltreatment data.