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Terrestrial ecosystem respiration increases exponentially with temperature, constituting a positive feedback loop accelerating global warming. However, the response of ecosystem respiration to temperature strongly depends on water availability, yet where and when the water effects are important, is presently poorly constrained, introducing uncertainties in climate-carbon cycle feedback projections. Here, we disentangle the effects of temperature and precipitation (a proxy for water availability) on ecosystem respiration by analysing eddy covariance CO 2 flux measurements across 212 globally distributed sites. We reveal a threshold precipitation function, determined by the balance between precipitation and ecosystem water demand, which separates temperature-limited and water-limited respiration. Respiration is temperature limited for precipitation above that threshold function, whereas in drier areas water limitation reduces the temperature sensitivity of respiration and its positive feedback to global warming. If the trend of expansion of water-limited areas with warming climate over the last decades continues, the positive feedback of ecosystem respiration is likely to be weakened and counteracted by the increasing water limitation., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

A shift to higher temperatures has left the Mediterranean Europe and Northern Africa (MENA) region more vulnerable to drought and land degradation. We used MODIS LAI (leaf area index) and GPP (gross primary production) deficits, the differences between actual and historical-maximum values, to describe vegetation structural and functional changes and consequential landcover change in response to changing climate conditions during 2001-2019 in the area (20° W-45° E, 20° N-45° N). We found that 1) the vegetation responses varied significantly among eight landcover types with the decreasing importance: forests, savannas, a mosaic of cropland and natural vegetation (CNV), croplands, permanent wetlands, urban land, grasslands, and shrublands, each with distinctive yet overlapping signatures over the ranges of the climate conditions considered. 2) Forests, occupying the coolest and wettest niche, showed the strongest response to severe drought with a lag of 1-3 years and a legacy effect for 10 years. Shrubs, occupying the hottest and driest niche, were the most resilient under a hotter and drier climate. 3) The total areas of savannas and CNV increased by 394,994 and 404,592 km 2 , respectively, while that of forests decreased by 33,091 km 2 . Shrublands extended by 287,134 km 2 while grasslands and croplands retreated by 490,644 and 225,263 km 2 . The area of wetlands increased by 49,192 km 2 , and that of urban land increased by 39,570 km 2 . A total of 57,649 km 2 of barren land became vegetated over the years. Along with higher temperature and more extended period of drought, MENA has evolved towards a shrubbier landscape., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To establish the feasibility and effectiveness of a 6-week ballistic strength training protocol in people with stroke., Design: Randomized, controlled, assessor-blinded study., Setting: Subacute inpatient rehabilitation., Participants: Consecutively admitted inpatients with a primary diagnosis of first-ever stroke with lower limb weakness, functional ambulation category score of ≥3, and ability to walk ≥14 m were screened for eligibility to recruit 30 participants for randomization., Interventions: Participants were randomized to standard therapy or ballistic strength training 3 times per week for 6 weeks., Main Outcome Measures: The primary aim was to evaluate feasibility and outcomes included recruitment rate, participant retention and attrition, feasibility of the exercise protocol, therapist burden, and participant safety. Secondary outcomes included measures of mobility, lower limb muscle strength, muscle power, and quality of life., Results: A total of 30 participants (11% of those screened) with mean age of 50 years (SD 18) were randomized. The median number of sessions attended was 15 of 18 and 17 of 18 for the ballistic and control groups, respectively. Earlier than expected discharge to home (n=4) and illness (n=7) were the most common reasons for nonattendance. Participants performed the exercises safely, with no study-related adverse events. There were significant (P<.05) between-group changes favoring the ballistic group for comfortable gait velocity (mean difference [MD] 0.31m/s, 95% confidence interval [CI]: 0.08-0.52), muscle power, as measured by peak jump height (MD 8cm, 95% CI: 3-13), and peak propulsive velocity (MD 64cm/s, 95% CI: 17-112)., Conclusions: Ballistic training was safe and feasible in select ambulant people with stroke. Similar rates of retention and attrition suggest that ballistic training was acceptable to patients. Secondary outcomes provide promising results that warrant further investigation in a larger trial., (Copyright © 2018 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)

Objective: To determine whether resistance training to improve mobility outcomes after stroke adheres to the American College of Sports Medicine (ACSM) guidelines, and whether adherence was associated with better outcomes., Data Sources: Online databases searched from 1975 to October 30, 2016., Study Selection: Randomized controlled trials examining the effectiveness of lower limb strength training on mobility outcomes in adult participants with stroke., Data Extraction: Two independent reviewers completed data extraction. Quality of trials was determined using the Cochrane Risk of Bias Tool. Trials were scored based on their protocol's adherence to 8 ACSM recommendations. To determine if a relation existed between total adherence score and effect size, Spearman ρ was calculated, and between individual recommendations and effect size, Mann-Whitney U or Kruskal-Wallis tests were used., Data Synthesis: Thirty-nine trials met the inclusion criteria, and 34 were scored on their adherence to the guidelines. Adherence was high for frequency of training (100% of studies), but few trials adhered to the guidelines for intensity (32%), specificity (24%), and training pattern (3%). Based on the small number of studies that could be included in pooled analysis (n=12), there was no relation between overall adherence and effect size (Spearman ρ=-.39, P=.21)., Conclusions: Adherence to the ACSM guidelines for resistance training after stroke varied widely. Future trials should ensure strength training protocols adhere more closely to the guidelines, to ensure their effectiveness in stroke can be accurately determined., (Copyright © 2017 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)