84 research outputs found

    A simple noninvasive pressure–time index at the mouth to measure respiratory load during acute exacerbation of COPD A comparison with normal volunteers

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    AbstractWe assessed the validity of the pressure–time index (PTI) measured at the mouth as a noninvasive and simplified alternative to conventional tension–time index for assessing respiratory load and inspiratory muscle force reserve. PTI was measured within 48 h of hospital admission and at 24 h before discharge in 37 consecutive patients with acute exacerbation of chronic obstructive pulmonary disease(COPD) using the equation PTI = (Pawo/MIP)(TI/TT)100, where Pawo is the mean airway pressure measured at the mouth, MIP the maximal inspiratory pressure, andTI /TT the inspiratory time (TI) to total cycle length (TT) ratio. Controls were 30 normal volunteers with similar anthropometric features. Mean (± SD) PTI values were significantly higher in COPD patients (0.29 ± 0.10) than in controls (0.11 ± 0.04) (P<0.001) primarily because MIP and TI/TT were significantly lower and Pawo was higher in the COPD population than in controls. As a result of improvement of the respiratory condition, PTI values were significantly lower at discharge (0.20±0.10 vs. 0.29±0.10, P<0.001) due to a drop in Pawo and an increase in MIP. The accuracy of different PTI cutpoints was assessed by comparison of the receiver operating characteristics curves. Best cutpoint values for differentiating COPD patients on admission and at hospital discharge from controls were 0.13 (positive predictive value 76%) and 0.17 (positive predictive value 92%), respectively. Noninvasive PTI measured at the mouth provides a valid and easy method for assessing respiratory muscle load and reserve. Changes in PTI values reflect functional improvement following treatment of acute exacerbation of COPD

    Awareness of cognitive decline trajectories in asymptomatic individuals at risk for AD

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    Background: Lack of awareness of cognitive decline (ACD) is common in late-stage Alzheimer’s disease (AD). Recent studies showed that ACD can also be reduced in the early stages. Methods: We described different trends of evolution of ACD over 3 years in a cohort of memory-complainers and their association to amyloid burden and brain metabolism. We studied the impact of ACD at baseline on cognitive scores’ evolution and the association between longitudinal changes in ACD and in cognitive score. Results: 76.8% of subjects constantly had an accurate ACD (reference class). 18.95% showed a steadily heightened ACD and were comparable to those with accurate ACD in terms of demographic characteristics and AD biomarkers. 4.25% constantly showed low ACD, had significantly higher amyloid burden than the reference class, and were mostly men. We found no overall effect of baseline ACD on cognitive scores’ evolution and no association between longitudinal changes in ACD and in cognitive scores. Conclusions: ACD begins to decrease during the preclinical phase in a group of individuals, who are of great interest and need to be further characterized. Trial registration: The present study was conducted as part of the INSIGHT-PreAD study. The identification number of INSIGHT-PreAD study (ID-RCB) is 2012-A01731-42

    Regional variability in peatland burning at mid- to high-latitudes during the Holocene

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    Acknowledgements This work developed from the PAGES (Past Global Changes) C-PEAT (Carbon in Peat on EArth through Time) working group. PAGES has been supported by the US National Science Foundation, Swiss National Science Foundation, Swiss Academy of Sciences and Chinese Academy of Sciences. We acknowledge the following financial support: UK Natural Environment Research Council Training Grants NE/L002574/1 (T.G.S.) and NE/S007458/1 (R.E.F.); Dutch Foundation for the Conservation of Irish Bogs, Quaternary Research Association and Leverhulme Trust RPG-2021-354 (G.T.S); the Academy of Finland (M.V); PAI/SIA 80002 and FONDECYT Iniciación 11220705 - ANID, Chile (C.A.M.); R20F0002 (PATSER) ANID Chile (R.D.M.); Swedish Strategic Research Area (SRA) MERGE (ModElling the Regional and Global Earth system) (M.J.G.); Polish National Science Centre Grant number NCN 2018/29/B/ST10/00120 (K.A.); Russian Science Foundation Grant No. 19-14-00102 (Y.A.M.); University of Latvia Grant No. AAp2016/B041/Zd2016/AZ03 and the Estonian Science Council grant PRG323 (TrackLag) (N.S. and A.M.); U.S. Geological Survey Land Change Science/Climate Research & Development Program (M.J., L.A., and D.W.); German Research Foundation (DFG), grant MA 8083/2-1 (P.M.) and grant BL 563/19-1 (K.H.K.); German Academic Exchange Service (DAAD), grant no. 57044554, Faculty of Geosciences, University of Münster, and Bavarian University Centre for Latin America (BAYLAT) (K.H.K). Records from the Global Charcoal Database supplemented this work and therefore we would like to thank the contributors and managers of this open-source resource. We also thank Annica Greisman, Jennifer Shiller, Fredrik Olsson and Simon van Bellen for contributing charcoal data to our analyses. Any use of trade, firm, or product name is for descriptive purposes only and does not imply endorsement by the U.S. Government.Peer reviewedPostprin

    From influence to impact: the multifunctional land-use in Mediterranean prehistory emerging from palynology of archaeological sites (8.0-2.8 ka BP)

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    Archaeobotany is used to discover details on local land uses in prehistoric settlements developed during the middle and beginning of late Holocene. Six archaeological sites from four countries (Spain, Italy, Greece, and Turkey) have pollen and charcoal records showing clear signs of the agrarian systems that had developed in the Mediterranean basin during different cultural phases, from pre-Neolithic to Recent Bronze Age. A selected list of pollen taxa and sums, including cultivated trees, other woody species, crops and annual or perennial synanthropic plants are analysed for land use reconstructions. In general, cultivation has a lower image in palynology than forestry, and past land uses became visible when oakwoods were affected by human activities. On-site palynology allows us to recognise the first influence of humans even before it can be recognised in off-site sequences, and off-site sequences can allow us to determine the area of influence of a site. Neolithic and Bronze Age archaeological sites show similar land use dynamics implying oak exploitation, causing local deforestation, and cultivation of cereal fields in the area or around the site. Although a substantial difference makes the Neolithic influence quite distant from the Bronze Age impact, mixed systems of land exploitation emerged everywhere. Multiple land use activities exist (multifunctional landscapes) at the same time within the area of influence of a site. Since the Neolithic, people have adopted a diffuse pattern of land use involving a combination of diverse activities, using trees\u2013crops\u2013domesticated animals. The most recurrent combination included wood exploitation, field cultivation and animal breeding. The lesson from the past is that the multifunctional land use, combining sylvo-pastoral and crop farming mixed systems, has been widely adopted for millennia, being more sustainable than the monoculture and a promising way to develop our economy

    Regional variability in peatland burning at mid-to high-latitudes during the Holocene

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    Northern peatlands store globally-important amounts of carbon in the form of partly decomposed plant detritus. Drying associated with climate and land-use change may lead to increased fire frequency and severity in peatlands and the rapid loss of carbon to the atmosphere. However, our understanding of the patterns and drivers of peatland burning on an appropriate decadal to millennial timescale relies heavily on individual site-based reconstructions. For the first time, we synthesise peatland macrocharcoal records from across North America, Europe, and Patagonia to reveal regional variation in peatland burning during the Holocene. We used an existing database of proximal sedimentary charcoal to represent regional burning trends in the wider landscape for each region. Long-term trends in peatland burning appear to be largely climate driven, with human activities likely having an increasing influence in the late Holocene. Warmer conditions during the Holocene Thermal Maximum (∼9–6 cal. ka BP) were associated with greater peatland burning in North America's Atlantic coast, southern Scandinavia and the Baltics, and Patagonia. Since the Little Ice Age, peatland burning has declined across North America and in some areas of Europe. This decline is mirrored by a decrease in wider landscape burning in some, but not all sub-regions, linked to fire-suppression policies, and landscape fragmentation caused by agricultural expansion. Peatlands demonstrate lower susceptibility to burning than the wider landscape in several instances, probably because of autogenic processes that maintain high levels of near-surface wetness even during drought. Nonetheless, widespread drying and degradation of peatlands, particularly in Europe, has likely increased their vulnerability to burning in recent centuries. Consequently, peatland restoration efforts are important to mitigate the risk of peatland fire under a changing climate. Finally, we make recommendations for future research to improve our understanding of the controls on peatland fires
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