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- Eliasson, JH, et al.
(author)
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The prevalence of hypnic headache in Iceland
- 2020
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In: Cephalalgia : an international journal of headache. - : SAGE Publications. - 1468-2982. ; 40:8, s. 863-865
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Journal article (peer-reviewed)abstract
- To determine the prevalence of hypnic headache. Background The exact prevalence of hypnic headache is unknown since there are no published population-based prevalence studies. Methods This study was a pilot for the SAGA cohort study, a population-based study on life stressors and various indices of health. Of 1398 invited adults, 921 (66%) participated; 402 men (average age 45.6 years, SD 13.2) and 519 women (52.6 years, SD 11.1). Subjects answered a headache questionnaire including a screening question for hypnic headache. “Do you have a headache that occurs only during sleep and causes wakening?”. Diagnosis of hypnic headache was made by clinical interview using ICHD-3 criteria. Results Among 921 participants, six screened positive for hypnic headache, of those two 0.22% (95% CI 0.06–0.79%) had probable hypnic headache and none had definite hypnic headache. Conclusion Confirming that hypnic headache is rare, these data suggest a 0.22% prevalence of probable hypnic headache.
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- Wilson, Scott D., et al.
(author)
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Functional Group, Biomass, and Climate Change Effects on Ecological Drought in Semiarid Grasslands
- 2018
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In: Journal of Geophysical Research - Biogeosciences. - 2169-8953 .- 2169-8961. ; 123:3, s. 1072-1085
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Journal article (peer-reviewed)abstract
- Water relations in plant communities are influenced both by contrasting functional groups (grasses and shrubs) and by climate change via complex effects on interception, uptake, and transpiration. We modeled the effects of functional group replacement and biomass increase, both of which can be outcomes of invasion and vegetation management, and climate change on ecological drought (soil water potential below which photosynthesis stops) in 340 semiarid grassland sites over 30year periods. Relative to control vegetation (climate and site-determined mixes of functional groups), the frequency and duration of drought were increased by shrubs and decreased by annual grasses. The rankings of shrubs, control vegetation, and annual grasses in terms of drought effects were generally consistent in current and future climates, suggesting that current differences among functional groups on drought effects predict future differences. Climate change accompanied by experimentally increased biomass (i.e., the effects of invasions that increase community biomass or management that increases productivity through fertilization or respite from grazing) increased drought frequency and duration and advanced drought onset. Our results suggest that the replacement of perennial temperate semiarid grasslands by shrubs, or increased biomass, can increase ecological drought in both current and future climates.
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