Importance Of Additional Variables Research Articles

Depression and sleep quality in older adults: a meta-analysis

The literature emphasizes depression and poor sleep quality as problems that affect many elderly individuals. However, these problems have been related in few studies and there is no meta-analysis performed so far on this relationship. The present research reviewed the studies performed on the subjective sleep quality in order to understand how it relates to depression in older adults. The review was conducted in January 2016 and comprised publications between 2005 and 2015. Based on the electronic databases Web of Science and EBSCO, we used the keywords ‘sleep quality’, ‘depression’, and ‘older’ to identify the empirical studies performed. After assessing the collected studies, we selected those that presented the elderly as participants, resulting in nine papers (N = 3069). A random-effects method was used to evaluate the relationship between depression and sleep. We found that an older person’s lack of good sleep quality is significantly related with depression. The main limitation of this study was the difficulty in collecting a greater number of studies. Future research should consider the importance of additional variables (e.g. moderators) in order to understand and investigate viable interventions for prevention and health promotion in the elderly.

Estimating postfire survival of Douglas-fir in the Cascade Range

Factors related to survival of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) 2 years after spring wildfires were evaluated at four sites in the Cascade Range. A logistic regression model was developed to estimate postfire survival. Crown scorch and three variables related to bole damage were significant in the regression model, with differences in response among sites attributed to differences in size class. The regression model predicted postfire response of live trees more accurately than that of dead trees, based on estimates of survival probability. Crown scorch was the most significant predictor of tree response, although the importance of additional variables indicated that evaluating bole damage greatly improves postfire survival estimates.