RESUMO
The semi-arid forest ecosystems of western Iran dominated by Quercus brantii are often disturbed by wildfires. Here, we assessed the effects of short fire intervals on the soil properties and community diversity of herbaceous plants and arbuscular mycorrhizal fungi (AMF), as well as the interactions between these ecosystem features. Plots burned once or twice within 10 years were compared to unburned plots over a long time period (control sites). Soil physical properties were not affected by the short fire interval, except bulk density, which increased. Soil geochemical and biological properties were affected by the fires. Soil organic matter and nitrogen concentrations were depleted by two fires. Short intervals impaired microbial respiration, microbial biomass carbon, substrate-induced respiration, and urease enzyme activity. The successive fires affected the AMF's Shannon diversity. The diversity of the herb community increased after one fire and dropped after two, indicating that the whole community structure was altered. Two fires had greater direct than indirect effects on plant and fungal diversity, as well as soil properties. Short-interval fires depleted soil functional properties and reduced herb diversity. With short-interval fires probably fostered by anthropogenic climate change, the functionalities of this semi-arid oak forest could collapse, necessitating fire mitigation.
RESUMO
Sleep complaints are common in hemodialysis (HD) patients. Sleep quality (SQ) is a predictor of quality of life and mortality risk in HD. The aim of this study was to examine factors that may have a role in SQ. In this cross-sectional analytic study, 138 end-stage renal disease patients receiving maintenance HD for >3 months were included. The Pittsburgh Sleep Quality Index (PSQI) was used to measure individual's SQ. Patients with a global PSQI score >5 were assumed as poor sleepers. Eighty-eight patients (64%) were classified as poor sleepers. Poor sleepers were older and more likely had diabetes. They had significantly higher serum ferritin and calcium levels and lower serum parathyroid hormone level (all P-values <0.05). The global PSQI score was positively correlated with age, serum calcium level and presence of diabetes as the underlying cause of renal failure. In the multi-variable binary regression model, presence of diabetes (Odds Ratio (OR) = 3.67, P = 0.008) and body pain (OR = 1.182, P = 0.014) were the significant independent predictors for poor SQ. Poor SQ was common among our HD patients, especially among diabetic cases and, therefore, there is a need to pay more attention to the care of this subgroup with regard to the diagnosis and management of sleep complaints.
