Increased drought severity tracks warming in the United States' largest river basin.

Across the Upper Missouri River Basin, the recent drought of 2000 to 2010, known as the "turn-of-the-century drought," was likely more severe than any in the instrumental record including the Dust Bowl drought. However, until now, adequate proxy records needed to better understand this event with regard to long-term variability have been lacking. Here we examine 1,200 y of streamflow from a network of 17 new tree-ring-based reconstructions for gages across the upper Missouri basin and an independent reconstruction of warm-season regional temperature in order to place the recent drought in a long-term climate context. We find that temperature has increasingly influenced the severity of drought events by decreasing runoff efficiency in the basin since the late 20th century (1980s) onward. The occurrence of extreme heat, higher evapotranspiration, and associated low-flow conditions across the basin has increased substantially over the 20th and 21st centuries, and recent warming aligns with increasing drought severities that rival or exceed any estimated over the last 12 centuries. Future warming is anticipated to cause increasingly severe droughts by enhancing water deficits that could prove challenging for water management.

The Influence of Parental Self-Efficacy and Perceived Control on the Home Learning Environment of Young Children.

OBJECTIVE: To: 1) examine sociodemographic factors associated with high parental self-efficacy and perceived control, and 2) determine how self-efficacy and control relate to the home learning environment (HLE), including whether they mediate the relationship between sociodemographic characteristics and HLE, among low-income parents of young children. METHODS: Cross-sectional survey of English- and Spanish-speaking parents, 18 years of age and older, with children 15 to 36 months old, to assess parental self-efficacy, perceived control, HLE, and sociodemographic characteristics. Bivariate analysis identified sociodemographic predictors of high self-efficacy and control. Separate multivariate linear regression models were used to examine associations between self-efficacy, control, and the HLE. Formal path analysis was used to assess whether self-efficacy and control mediate the relationship between sociodemographic characteristics and HLE. RESULTS: Of 144 participants, 25% were white, 65% were immigrants, and 35% completed the survey in Spanish. US-born subjects, those who completed English surveys, or who had higher educational levels had significantly higher mean self-efficacy and perceived control scores (P < .05). Higher self-efficacy and perceived control were associated with a positive change in HLE score in separate multivariate models (self-efficacy ß = .7 [95% confidence interval (CI), 0.5-0.9]; control ß = .5 [95% CI, 0.2-0.8]). Self-efficacy acted as a mediator such that low self-efficacy explained part of the association between parental depressive symptoms, immigrant status, and less optimal HLE (P = .04 and < .001, respectively). CONCLUSIONS: High parental self-efficacy and perceived control positively influence HLEs of young children. Self-efficacy alone mediates the relationship between parental depressive symptoms, immigrant status, and less optimal early home learning.

Variations in hepatic biomarkers in American alligators (Alligator mississippiensis) from three sites in Florida, USA.

Sub-individual biomarkers are sub-lethal biological responses commonly used in the assessment of wildlife exposure to environmental contaminants. In this study, we examined the activity of glutathione-s-transferase (GST) and lactate dehydrogenase (LDH), and metallothionein (MT) concentrations among captive-raised alligator hatchlings, wild-caught juveniles, and wild-caught adults. Juveniles and adults were collected from three locations in Florida (USA) with varying degrees of contamination (i.e. Lake Apopka (organochlorine polluted site), Merritt Island National Wildlife Refuge (NWR) (metal polluted site), and Lake Woodruff NWR (reference site)). We examined whether changes in the response of these three biomarkers were age and sex dependent or reflected site-specific variations of environmental contaminants. Juvenile alligators from Merritt Island NWR had higher MT concentrations and lower GST activity compared to those from the other two sites. This outcome was consistent with higher metal pollution at this location. Sexually dimorphic patterns of MT and GST (F > M) were observed in juvenile alligators from all sites, although this pattern was not observed in adults. GST activity was lower in captive-raised alligators from Lake Apopka and Merritt Island NWR as compared to animals from Lake Woodruff NWR, suggesting a possible developmental modulator at these sites. No clear patterns were observed in LDH activity. We concluded that GST and MT demonstrate age and sex specific patterns in the alligators inhabiting these study sites and that the observed variation among sites could be due to differences in contaminant exposure.