Damage due to wind-storms and droughts is increasing in many temperate forests, yet little is known about the long-term roles of these key climatic factors in forest dynamics and in the carbon budget. The objective of this study was to estimate individual and coupled effects of droughts and wind-storms on adult tree mortality across a 31-year period in 115 managed, mixed coniferous forest stands from the Western Alps and the Jura mountains. For each stand, yearly mortality was inferred from management records, yearly drought from interpolated fields of monthly temperature, precipitation and soil water holding capacity, and wind-storms from interpolated fields of daily maximum wind speed. We performed a thorough model selection based on a leave-one-out cross-validation of the time series. We compared different critical wind speeds (CWSs) for damage, wind-storm, and stand variables and statistical models. We found that a model including stand characteristics, drought, and storm strength using a CWS of 25 ms performed the best across most stands. Using this best model, we found that drought increased damage risk only in the most southerly forests, and its effect is generally maintained for up to 2 years. Storm strength increased damage risk in all forests in a relatively uniform way. In some stands, we found positive interaction between drought and storm strength most likely because drought weakens trees, and they became more prone to stem breakage under wind-loading. In other stands, we found negative interaction between drought and storm strength, where excessive rain likely leads to soil water saturation making trees more susceptible to overturning in a wind-storm. Our results stress that temporal data are essential to make valid inferences about ecological impacts of disturbance events, and that making inferences about disturbance agents separately can be of limited validity. Under projected future climatic conditions, the direction and strength of these ecological interactions could also change.
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A multi-instrument study is conducted at the dayside polar ionosphere to investigate the spatio-temporal evolution of scintillation in Global Navigation Satellite System (GNSS) signals during non-storm conditions. Bursts of intense amplitude and phase scintillation started to occur at 9 MLT and persisted for more than 1 hour implying the simultaneous existence of Fresnel and large-scale sized irregularities of significant strength in the pre-noon sector. Measurements from the EISCAT radar in Svalbard (ESR) revealed the presence of dense plasma structures with significant gradients in regions of strong Joule heating/fast flows and soft precipitation when scintillation was enhanced.
View Article and Find Full Text PDFA fundamental characteristic of extreme precipitation events (EPEs) is their horizontal scale. This horizontal scale can influence the intensity of an EPE through its effect on the timescale of an EPE as well as its effect on the strength of convective feedbacks. Thus, to have confidence in future projections of extreme precipitation, the horizontal scales of EPEs in global climate models (GCMs) should be evaluated.
View Article and Find Full Text PDFCells
October 2024
Department of Natural Compound, Nutrition, and Health, MIGAL Galilee Research Institute, Kiryat Shmona 1101600, Israel.
The onset of SARS-CoV-2 infection in 2019 sparked a global COVID-19 pandemic. This infection is marked by a significant rise in both viral and host kinase activity. Our primary objective was to identify a pivotal host kinase essential for COVID-19 infection and the associated phenomenon of the cytokine storm, which may lead to long-term COVID-19 complications irrespective of viral genetic variations.
View Article and Find Full Text PDFOrthop J Sports Med
October 2024
H-Hip, Department of Physio and Occupational Therapy and Orthopaedic Surgery, Horsens Regional Hospital, Horsens, Denmark.
Background: Surgical treatment of patients with proximal hamstring avulsions provides good results; however, less is known about the outcome in patients who are offered conservative treatment.
Purpose: To investigate the effect of surgical or conservative treatment (decided by a shared decision strategy) of proximal hamstring avulsions.
Study Design: Cohort study; Level of evidence, 2.
J Acoust Soc Am
October 2024
Center for Coastal and Ocean Mapping, University of New Hampshire, Durham, New Hampshire 03824, USA.
In the ocean, the performance of active sonar systems depends on the acoustic properties of the seafloor. Daily to monthly variations in near-bottom hydrodynamics and benthic biological activity may affect seafloor properties which then influence the acoustic response of the seafloor. The dependence of seafloor scatter on evolving environmental parameters was investigated using high-frequency active acoustic systems.
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