A model intercomparison project to study the role of plant functional diversity in the response of tropical forests to drought

Uncertainty in how the land carbon (C) sink will change over time contributes to uncertainty in Earth system model (ESM) projections of climate change. Much of the land sink is thought to reside in old-growth tropical forests, but recent analyses suggest a diminishing C sink in these forests due to rising temperatures and drought. Thus, there is an urgent need to better understand tropical forest responses to drought and to incorporate this understanding into ESMs. Previous work with vegetation demographic models (VDMs) – which represent the dynamics of individuals or cohorts, along with hydrology and biogeochemistry − suggest that functional diversity can enhance tropical forest resilience to climate change. However, there is little understanding of how different approaches to representing trait diversity and demography affect model outcomes. To explore the potential for trait diversity to moderate tropical forest responses to drought, we explored the behavior of nine VDMs, ranging from models with detailed site-level parameterizations to more generalized land models designed as ESM components. The behavior of each model was studied using soil and meteorological data collected at each of two tropical forest sites: Paracou Research Station, French Guiana, and Tapajos National Forest, Brazil. Low and high trait-diversity scenarios were simulated for each model using historical meteorology, as well as reduced rainfall scenarios. Few models showed strong effects of trait diversity on drought resistance (short-term response of forest biomass to rainfall reduction), but most models showed positive effects of diversity on resilience (long-term recovery of forest biomass following the initial biomass loss due to rainfall reduction). Long-term recovery was always associated with shifts in community composition towards greater drought-tolerance. However, there were large differences among models in the degree and time-scale of recovery. These differences were unrelated to the goodness-of-fit of model predictions to observations of biomass, productivity, and soil moisture, suggesting that site-level calibration of model parameters is unlikely to strongly affect biodiversity-ecosystem functioning relationships in VDMs. Rather, the degree to which diversity moderated drought responses depended on which axes of trait variation were represented in the model, as well as model assumptions that affect the time-scale over which community composition shifts in response to environmental change. Our study suggests that incorporating trait diversity and demography into ESMs would likely lead to altered climate projections, but additional empirical and modeling work is needed to provide the ESM community with clear guidance on model development

Krajnjem korisniku prilagođeni programski jezici za poosobljavanje računalom upravljanih okolina

The increased usage of smart devices and appliances opens new venues to build applications that integrate physical and virtual world into consumer-oriented context-sensitive cyber-physical systems (CPS). Since physical processes are dynamic, concurrent, event-driven, and powered by various sensors, controllers, and actuators, a combination of service-oriented architecture (SOA) and event-driven architecture (EDA) is the most promising software architecture for virtualization of heterogeneous components into interoperable application building blocks. In this paper, we propose a CPS design paradigm where devices, such as sensors, controllers, and actuators, are virtualized into environmental services. To support event-driven workflow coordination, we designed special-purpose coopetition services that provide fundamental EDA characteristics, such as decoupled interactions, many-to-many communication, publish/subscribe messaging, event triggering, and asynchronous operations. Based on these two groups of services, we present a design of event-driven service composition languages that target two distinct groups of developers. Using Python as an example, we present a transformation of arbitrary general-purpose programming language into an event-driven service composition language for developers familiar with parallel programming using operating system kernel mechanisms. On the other hand, we present the design and cognitive evaluation of an end-user language, whose 2D tabular workspace resembles the process of sketching an automation application on a sheet of paper.Povećanom uporabom suvremenih elektroničkih uređaja otvaraju se nove mogućnosti za izgradnju primjenskih programa koji objedinjuju fizički prostor i informacijske sustave u korisniku usmjerene računalom upravljane okoline. Suvremeni prostori opremljeni su različitim vrstama osjetila, upravljača i pokretačkih uređaja koji vremenski usklađeno upravljaju dinamičkim i događajima poticanim paralelnim procesima. Spregom uslužno usmjerene i događajima poticane arhitekture omogućen je pristup raznorodnim fizičkim uređajima u obliku međusobno sukladnih gradivnih komponenti primjenskih programa. U radu je predložena paradigma izgradnje računalom upravljanih okolina u kojoj se uređajima iz okoline pristupa putem programskih usluga. Za potrebe oblikovanja događajima poticanih tijekova izvođenja programa, oblikovan je poseban skup usluga suradnje i natjecanja. Te usluge ostvaruju osnovne značajke arhitekture zasnovane na događajima, kao što su neizravno međudjelovanje, komunikacija u grupi, objavi/pretplati komunikacija, pokretanje događaja i asinkrone operacije. Na osnovi tih dviju skupina usluga, oblikovana su dva jezika za događajima poticanu kompoziciju usluga. Na primjeru jezika Python, prikazano je preoblikovanje jezika opće namjene u jezik za događajima poticanu kompoziciju usluga namijenjen razvijateljima paralelnih programa primjenom mehanizama jezgre operacijskog sustava. S druge strane, prikazano je oblikovanje i kognitivno vrednovanje tabličnog jezika namijenjenog krajnjem korisniku, gdje oblikovanje primjenskog programa unutar dvodimenzionalne radne plohe nalikuje skiciranju međudjelovanja skupine uređaja na listu papira

Large hydraulic safety margins protect Neotropical canopy rainforest tree species against hydraulic failure during drought

AbstractKey messageAbundant Neotropical canopy-tree species are more resistant to drought-induced branch embolism than what is currently admitted. Large hydraulic safety margins protect them from hydraulic failure under actual drought conditions.ContextXylem vulnerability to embolism, which is associated to survival under extreme drought conditions, is being increasingly studied in the tropics, but data on the risk of hydraulic failure for lowland Neotropical rainforest canopy-tree species, thought to be highly vulnerable, are lacking.AimsThe purpose of this study was to gain more knowledge on species drought-resistance characteristics in branches and leaves and the risk of hydraulic failure of abundant rainforest canopy-tree species during the dry season.MethodsWe first assessed the range of branch xylem vulnerability to embolism using the flow-centrifuge technique on 1-m-long sun-exposed branches and evaluated hydraulic safety margins with leaf turgor loss point and midday water potential during normal- and severe-intensity dry seasons for a large set of Amazonian rainforest canopy-tree species.ResultsTree species exhibited a broad range of embolism resistance, with the pressure threshold inducing 50% loss of branch hydraulic conductivity varying from − 1.86 to − 7.63 MPa. Conversely, we found low variability in leaf turgor loss point and dry season midday leaf water potential, and mostly large, positive hydraulic safety margins.ConclusionsRainforest canopy-tree species growing under elevated mean annual precipitation can have high resistance to embolism and are more resistant than what was previously thought. Thanks to early leaf turgor loss and high embolism resistance, most species have a low risk of hydraulic failure and are well able to withstand normal and even severe dry seasons

Contemporary Presentation and Management of Valvular Heart Disease The EURObservational Research Programme Valvular Heart Disease II Survey

International audienceBackground: Valvular heart disease (VHD) is an important cause of mortality and morbidity and has been subject to important changes in management. The VHD II survey was designed by the EURObservational Research Programme of the European Society of Cardiology to analyze actual management of VHD and to compare practice with guidelines. Methods: Patients with severe native VHD or previous valvular intervention were enrolled prospectively across 28 countries over a 3-month period in 2017. Indications for intervention were considered concordant if the intervention was performed or scheduled in symptomatic patients, corresponding to Class I recommendations specified in the 2012 European Society of Cardiology and in the 2014 American Heart Association/American College of Cardiology VHD guidelines. Results: A total of 7247 patients (4483 hospitalized, 2764 outpatients) were included in 222 centers. Median age was 71 years (interquartile range, 62-80 years); 1917 patients (26.5%) were >= 80 years; and 3416 were female (47.1%). Severe native VHD was present in 5219 patients (72.0%): aortic stenosis in 2152 (41.2% of native VHD), aortic regurgitation in 279 (5.3%), mitral stenosis in 234 (4.5%), mitral regurgitation in 1114 (21.3%; primary in 746 and secondary in 368), multiple left-sided VHD in 1297 (24.9%), and right-sided VHD in 143 (2.7%). Two thousand twenty-eight patients (28.0%) had undergone previous valvular intervention. Intervention was performed in 37.0% and scheduled in 26.8% of patients with native VHD. The decision for intervention was concordant with Class I recommendations in symptomatic patients with severe single left-sided native VHD in 79.4% (95% CI, 77.1-81.6) for aortic stenosis, 77.6% (95% CI, 69.9-84.0) for aortic regurgitation, 68.5% (95% CI, 60.8-75.4) for mitral stenosis, and 71.0% (95% CI, 66.4-75.3) for primary mitral regurgitation. Valvular interventions were performed in 2150 patients during the survey; of them, 47.8% of patients with single left-sided native VHD were in New York Heart Association class III or IV. Transcatheter procedures were performed in 38.7% of patients with aortic stenosis and 16.7% of those with mitral regurgitation. Conclusions: Despite good concordance between Class I recommendations and practice in patients with aortic VHD, the suboptimal number in mitral VHD and late referral for valvular interventions suggest the need to improve further guideline implementation