Wageningen University and Research Centre

About: Wageningen University and Research Centre is a education organization based out in Wageningen, Netherlands. It is known for research contribution in the topics: Population & Sustainability. The organization has 23474 authors who have published 54833 publications receiving 2608897 citations.

Sleep Duration and Sleep Quality in Relation to 12-Year Cardiovascular Disease Incidence: The MORGEN Study

Abstract: Study Objectives: We studied sleep duration and sleep quality in relation to cardiovascular disease (CVD) incidence. Design/Setting: Dutch population-based cohort study. Participants: 20,432 men and women aged 20-65 y with no history of CVD. Interventions: N/A Measurements: Sleep duration and sleep quality were assessed by a self-administered questionnaire. Morbidity data, vital status, and causes of death were obtained through linkage with several national registries. Hazard ratios (HRs) and 95% confidence intervals (95% CIs) were calculated using Cox proportional hazards models. Results: During 10-15 years of follow-up, 1,486 CVD and 1,148 coronary heart disease (CHD) events occurred. Short sleepers (= 6 h) had a 15% higher risk of total CVD (HR: 1.15; 95%CI: 1.00-1.32) and a 23% higher risk of CHD (HR: 1.23 [1.04-1.45]) compared to normal sleepers (7 h) after adjustment for all confounders. Additional adjustment for intermediate biological risk factors attenuated these relative risks to 1.11 (0.97-1.27) for total CVD and to 1.19 (1.00-1.40) for CHD. Short sleepers with poor sleep quality had a 63% higher risk of CVD (HR: 1.63 [1.21-2.19]) and a 79% higher risk of CHD incidence (HR: 1.79 [1.24-2.58]) compared to normal sleepers with good sleep quality, after adjustments for all confounders. We observed no associations between long sleep duration (= 9 h) and CVD or CHD incidence. Conclusions: Short sleepers, especially those with poor sleep quality, have an increased risk of total CVD and CHD incidence. Future investigations should not only focus on sleep duration, but should also take sleep quality into account.

Microbe-mediated plant-soil feedback causes historical contingency effects in plant community assembly

Abstract: Plant-soil feedback affects performance and competitive ability of individual plants. However, the importance of plant-soil feedback in historical contingency processes and plant community dynamics is largely unknown. In microcosms, we tested how six early- successional plant species of secondary succession on ex-arable land induced plant-specific changes in soil community composition. Following one growth cycle of conditioning the soil community, soil feedback effects were assessed as plant performance in soil of their own as compared to soil from a mixture of the other five early-successional species. Performance was tested in monocultures and in mixed communities with heterospecific competition from mid- successional species. The role of soil microorganisms was determined by isolating the microbial component from the soil community, re-inoculating microorganisms into sterilized substrate, and analyzing plant biomass responses of the early- and mid-successional species. Plant-soil feedback responses of the early-successional species were negative and significantly increased when the plants were grown in a competitive environment with heterospecifics. In monocultures, three early-successional species experienced negative feedback in soil with a history of conspecifics, while all early-successional species experienced negative feedback when grown with interspecific competition. Interestingly, the nonnative forb Conyza canadensis showed the weakest soil feedback effect. Biomass production of the early- successional plant species was profoundly reduced by the microbial inocula, most strongly when exposed to inocula of conspecific origin. Molecular characterization of the fungal and bacterial rhizosphere communities revealed a relationship between plant biomass production and the composition of the dominant fungal species. Furthermore, our results show that, in early secondary succession, the early-successional plant species induce changes in the soil microbial community composition that cause historical contingency effects in dominance patterns of mid-succession plant communities. We conclude that feedback between early-successional plant species and soil microorgan- isms can play a crucial role in breaking dominance of early-successional plant communities. Moreover the influences on soil microorganism community composition influenced plant community dynamics in the mid-successional plant communities. These results shed new light on how feedback effects between plants and soil organisms in one successional stage result in a biotic legacy effect, which influences plant community processes in subsequent successional stages.