AbstractBackgroundSalinity, exacerbated by rising sea levels, is a critical environmental cue affecting freshwater ecosystems. Predicting ecosystem structure in response to such changes and their... Show moreAbstractBackgroundSalinity, exacerbated by rising sea levels, is a critical environmental cue affecting freshwater ecosystems. Predicting ecosystem structure in response to such changes and their implications for the geographical distribution of arthropod disease vectors requires further insights into the plasticity and adaptability of lower trophic level species in freshwater systems. Our study investigated whether populations of the mosquito Culex pipiens, typically considered sensitive to salt, have adapted due to gradual exposure.MethodsMesocosm experiments were conducted to evaluate responses in life history traits to increasing levels of salinity in three populations along a gradient perpendicular to the North Sea coast. Salt concentrations up to the brackish–marine transition zone (8 g/l chloride) were used, upon which no survival was expected. To determine how this process affects oviposition, a colonization experiment was performed by exposing the coastal population to the same concentrations.ResultsWhile concentrations up to the currently described median lethal dose (LD50) (4 g/l) were surprisingly favored during egg laying, even the treatment with the highest salt concentration was incidentally colonized. Differences in development rates among populations were observed, but the influence of salinity was evident only at 4 g/l and higher, resulting in only a 1-day delay. Mortality rates were lower than expected, reaching only 20% for coastal and inland populations and 41% for the intermediate population at the highest salinity. Sex ratios remained unaffected across the tested range.ConclusionsThe high tolerance to salinity for all key life history parameters across populations suggests that Cx. pipiens is unlikely to shift its distribution in the foreseeable future, with potential implications for the disease risk of associated pathogens. Show less
OBJECTIVES The aim of this study was to investigate the performance of the EuroSCORE II over time and dynamics in values of predictors included in the model.METHODS A cohort study was performed... Show moreOBJECTIVES The aim of this study was to investigate the performance of the EuroSCORE II over time and dynamics in values of predictors included in the model.METHODS A cohort study was performed using data from the Netherlands Heart Registration. All cardiothoracic surgical procedures performed between 1 January 2013 and 31 December 2019 were included for analysis. Performance of the EuroSCORE II was assessed across 3-month intervals in terms of calibration and discrimination. For subgroups of major surgical procedures, performance of the EuroSCORE II was assessed across 12-month time intervals. Changes in values of individual EuroSCORE II predictors over time were assessed graphically.RESULTS A total of 103 404 cardiothoracic surgical procedures were included. Observed mortality risk ranged between 1.9% [95% confidence interval (CI) 1.6-2.4] and 3.6% (95% CI 2.6-4.4) across 3-month intervals, while the mean predicted mortality risk ranged between 3.4% (95% CI 3.3-3.6) and 4.2% (95% CI 3.9-4.6). The corresponding observed:expected ratios ranged from 0.50 (95% CI 0.46-0.61) to 0.95 (95% CI 0.74-1.16). Discriminative performance in terms of the c-statistic ranged between 0.82 (95% CI 0.78-0.89) and 0.89 (95% CI 0.87-0.93). The EuroSCORE II consistently overestimated mortality compared to observed mortality. This finding was consistent across all major cardiothoracic surgical procedures. Distributions of values of individual predictors varied broadly across predictors over time. Most notable trends were a decrease in elective surgery from 75% to 54% and a rise in patients with no or New York Heart Association I class heart failure from 27% to 33%.CONCLUSIONS The EuroSCORE II shows good discriminative performance, but consistently overestimates mortality risks of all types of major cardiothoracic surgical procedures in the Netherlands.The EuroSCORE II model aims to support clinicians and their patients to determine whether benefits of cardiac surgery outweigh mortality risks associated with these procedures [1]. Show less
As first step the impact of herbivory and abiotic factors on population dynamics of Arabidopsis thaliana were studied. Ceutorhynchus atomus and C. contractus were identified as the major insect... Show moreAs first step the impact of herbivory and abiotic factors on population dynamics of Arabidopsis thaliana were studied. Ceutorhynchus atomus and C. contractus were identified as the major insect herbivores on A. thaliana population, reducing seed production by more than 40%. Mortality from February to April was identified as a key- factor. Next, variation in morphological and life history trait and sutability of A. thaliana as food for weevils for A. thaliana population growing in the dune and inland habitat were studied. These variatioan were genetically and environmentally based. Plants at its home site had the highest fitness, which demonstrates adaptation to local environment. To examine the cause of differences in plant defense we compared herbivory on fruits with data on glucosinolate concentration of seeds, collected in the field. Fruit damage by adult weevils and their larvae was not correlated with field concentration of glucosinolates. We conclude that other factors might also be involved in defense against herbivory by the weevils. Finally, to test if glucosinolates evolve as a contrasting selection pressure by different herbivores we look if the generalist herbivore Spodoptera exigua and the specialist herbivores Plutella xylostella were differently affected by chemical compounds in the leaves. No significant correlations were found between larval weight of P. xylostella and glucosinolates in the leaves but glucosinolates negatively correlated with larval weight of S. exigua. We suggest that generalist herbivores may play a major role in this process. Show less
A unifying framework is presented for describing the phenotypic coevolutionary dynamics of a general ecological community. We start from an individual-based approach allowing for the interaction of... Show moreA unifying framework is presented for describing the phenotypic coevolutionary dynamics of a general ecological community. We start from an individual-based approach allowing for the interaction of an arbitrary number of species. The adaptive dynamics of species's trait values are derived from the underlying population dynamics within the community; in consequence, the evolutionary process is driven by ecological change. We present a hierarchy of dynamical models for the investigation of coevolutionary systems. The necessity of stochastic treatment is demonstrated and deterministic approximations are derived where appropriate. The mathematical framework advanced here to our knowledge is the first one to combine the individual-based, stochastic perspective with a fully dynamical analysis of the phenotypic coevolutionary process. The hierarchy of models presented is particularly geared to infer evolutionary predictions from ecological assumptions. Applications to evolutionary dynamics both in predator-prey systems and under asymmetric competition demonstrate the versatility of our approach. Rich coevolutionary patterns are obtained and novel evolutionary phenomena are revealed. Deductions are given to derive various well-known equations from the literature of evolutionary modelling. Consequently the different domains of validity for these models are delineated and several ad-hoc assumptions are removed. In particular, equations central to the fields of evolutionary game theory, adaptive dynamics, replicator dynamics and reaction-diffusion models of phenotypic evolution are recovered and are identified as special cases within a dynamical theory of coevolution. Show less
