Data Descriptor : A European Multi Lake Survey dataset of environmental variables, phytoplankton pigments and cyanotoxins

Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent problem resulting from nutrient pollution and climate-change induced stressors, like poor transparency, increased water temperature and enhanced stratification. Consistency in data collection and analysis methods is necessary to achieve fully comparable datasets and for statistical validity, avoiding issues linked to disparate data sources. The European Multi Lake Survey (EMLS) in summer 2015 was an initiative among scientists from 27 countries to collect and analyse lake physical, chemical and biological variables in a fully standardized manner. This database includes in-situ lake variables along with nutrient, pigment and cyanotoxin data of 369 lakes in Europe, which were centrally analysed in dedicated laboratories. Publishing the EMLS methods and dataset might inspire similar initiatives to study across large geographic areas that will contribute to better understanding lake responses in a changing environment.Peer reviewe

Prospective individual patient data meta-analysis of two randomized trials on convalescent plasma for COVID-19 outpatients

Data on convalescent plasma (CP) treatment in COVID-19 outpatients are scarce. We aimed to assess whether CP administered during the first week of symptoms reduced the disease progression or risk of hospitalization of outpatients. Two multicenter, double-blind randomized trials (NCT04621123, NCT04589949) were merged with data pooling starting when = 50 years and symptomatic for <= 7days were included. The intervention consisted of 200-300mL of CP with a predefined minimum level of antibodies. Primary endpoints were a 5-point disease severity scale and a composite of hospitalization or death by 28 days. Amongst the 797 patients included, 390 received CP and 392 placebo; they had a median age of 58 years, 1 comorbidity, 5 days symptoms and 93% had negative IgG antibody-test. Seventy-four patients were hospitalized, 6 required mechanical ventilation and 3 died. The odds ratio (OR) of CP for improved disease severity scale was 0.936 (credible interval (CI) 0.667-1.311); OR for hospitalization or death was 0.919 (CI 0.592-1.416). CP effect on hospital admission or death was largest in patients with <= 5 days of symptoms (OR 0.658, 95%CI 0.394-1.085). CP did not decrease the time to full symptom resolution

Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer

To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L−1), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long-term average, during a summer heatwave was the highest (+4°C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient-rich lakes than nutrient concentrations and surface temperature

Power-leveling as an effect of group model building

Contains fulltext : 111780.pdf (author's version ) (Open Access)System Dynamics Conferenc

The Eye of the Beholder: A Case Example of Changing Clients' Perspectives Through Involvement in the Model Validation Process

Contains fulltext : 144855.pdf (publisher's version ) (Closed access)Validation is an important topic in the system dynamics ?eld. A large body of knowledge addresses validation tests and procedures. However, the use of validation in practice and its results are scarcely reported. This is surprising as some authors assume thatin order to build con?dence in a model, it is crucial to at least communicate the validation process and its results. In this paper, we described a validation process in direct interaction with clients. We describe the tests and procedures we employed to iteratively build and validate a simulation model with the National Health Care Institute (TheNetherlands) in a group model-building setting. The involvement challenged the clients’ opinions and in some cases led to changes in their mental models.7 juli 201513 p

The eye of the beholder: exploring the dynamics of regional differences in cataract treatment

Item does not contain fulltextResearch into the variance in healthcare practice in general focuses on the regional differences over a period of single year. By this focus it leaves out the dynamic nature of the interaction between demand and supply of healthcare. The dynamics of the interaction between demand and supply of cataract treatment in the Netherlands are explored in this paper. This study was initiated by the Dutch Health Care Insurance Board in order to improve policies for managing the Dutch healthcare system. With the use of group model building, a system dynamics model is created to generate insight into the growing number of cataract treatments and differences in the number of treatments between regions. The main source for the growth in number of cataract treatments is a gradual change in indication criteria. The simulations for the twelve provinces in the Netherlands show comparable behaviour. The timing between the simulations is different. Hence the distribution of the number of treatments over the provinces is different for each year. A possible source for difference in timing is the ratio between the population of a province and the number of ophthalmologists in that province. Hence, for assessing the variation of practice time studies are required

Sketching, Analogies, and Creativity - on the Shared Research Interests of Psychologists and Designers

Paper and pencil sketching, visual analogies, and creativityare intuitively interconnected in design. This paper reports on previousand current research activities of a psychologist (the 1st author) and anarchitect/designer (the 2nd author) on issues concerning sketching andanalogies, and analogies and creativity respectively. In this paper wetried to unite these findings into a combined theory on how sketching,analogies, and creativity interrelate. An appealing theory emerges. It ishypothesized that with no paper available or no expertise to use it,analogies can be used to support the creative process instead of sketches.This theory, however, is a tentative one that needs more research to beconfirmed