Browsing by Subject "Co-occurrence"
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Item Moose and deer resource selection and co-occurrence in northeast Minnesota(2019-08) McGraw, AmandaA parasite, Parelaphostrongylus tenuis, carried by white-tailed deer (Odocoileus virginianus) has often been cited as a significant factor contributing to moose (Alces alces) population declines. Moose suffer from neurologic disease and usually die when infected with P. tenuis. The strength of the three-way relationship between moose, deer, and P. tenuis, and the resulting negative impact on moose health, is thought to be driven by deer densities. Despite its importance for moose and deer management, only one peer-reviewed study to date has tested the relationship between deer and moose densities, and therefore the potential for parasite-mediated competition between moose and deer, using empirical data. A deer density threshold above which moose populations declined was identified using the empirical data collected for the study. However, the nature of the data and apparent outliers suggest that the modeling approach used to develop that threshold may not have been appropriate. Here we tested, using data from the original study, whether alternative models, including linear models and negative binomial models would be less sensitive to outliers and could better explain the relationship between deer and moose densities in this study system. We found no evidence in our analysis that moose density decreases as deer density increases. We conclude that while the proposed moose-deer-P. tenuis relationship could be partially density dependent, additional factors such as frequency dependence of disease transmission and shared use of resources by moose and deer should also be considered.Item The Role of Parental Responsiveness in the Development of Co-occurring ADHD and Anxiety Symptoms: Interplay of Genotype and Environment(2016-08) Yaylaci, Fatima TubaUsing a novel index of co-occurring psychopathology, this study aims to clarify three research questions: (1) Is co-occurring ADHD-anxiety in school years a continuation of these problems in preschool period? (2) Is parental unresponsiveness in the early years of life a risk factor in the development of co-occurring ADHD and anxiety problems in preschool and school age? (3) Does genetic risk moderate the effect of parental unresponsiveness on ADHD-anxiety co-occurrence? Participants included 361 families from the Early Growth and Development Study (EGDS), which employs a prospective adoption design. In each family unit, data were collected from the child adopted at birth, the adoptive mother and father, and the biological mother. For the present study, adoptive parent’s responsiveness was assessed at child age of 9, 18, and 27 months; biological parent ADHD symptoms were assessed at 56 months; child ADHD and anxiety symptoms were assessed when children are at 41/2 and 6 years of age. Path analyses were conducted for maternal and paternal responsiveness, separately. In both models, ADHD-anxiety co-occurrence at age 41/2 years significantly predicted ADHD-anxiety co-occurrence at 6 years. Neither maternal responsiveness, nor paternal responsiveness had a main effect on child co-occurrence of ADHD-anxiety at 41/2 years. There were significant interactions between genetic risk and maternal/paternal responsiveness in infancy predicting co-occurring ADHD-anxiety problems at 41/2 years. Findings highlight the importance of attending to excessively high parental responsiveness in the context of genetic risk, which is associated with higher co-occurring ADHD and anxiety problems around ages 41/2 and 6.