| 1. |
- Donis, Daphne, et al.
(författare)
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Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer
- 2021
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Ingår i: Limnology and Oceanography. - : John Wiley & Sons. - 0024-3590 .- 1939-5590. ; 66:12, s. 4314-4333
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Tidskriftsartikel (refereegranskat)abstract
- 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 degrees 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.
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| 2. |
- Mantzouki, Evanthia, et al.
(författare)
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Temperature Effects Explain Continental Scale Distribution of Cyanobacterial Toxins
- 2018
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Ingår i: Toxins. - : MDPI. - 2072-6651. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains.
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| 3. |
- Eriksson, Kimmo, et al.
(författare)
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Perceptions of the appropriate response to norm violation in 57 societies
- 2021
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Ingår i: Nature Communications. - : Nature Research. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Norm enforcement may be important for resolving conflicts and promoting cooperation. However, little is known about how preferred responses to norm violations vary across cultures and across domains. In a preregistered study of 57 countries (using convenience samples of 22,863 students and non-students), we measured perceptions of the appropriateness of various responses to a violation of a cooperative norm and to atypical social behaviors. Our findings highlight both cultural universals and cultural variation. We find a universal negative relation between appropriateness ratings of norm violations and appropriateness ratings of responses in the form of confrontation, social ostracism and gossip. Moreover, we find the country variation in the appropriateness of sanctions to be consistent across different norm violations but not across different sanctions. Specifically, in those countries where use of physical confrontation and social ostracism is rated as less appropriate, gossip is rated as more appropriate. Little is known about peoples preferred responses to norm violations across countries. Here, in a study of 57 countries, the authors highlight cultural similarities and differences in peoples perception of the appropriateness of norm violations.
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| 4. |
- Ozden, C., et al.
(författare)
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FDG Uptake in the Basal Forebrain as Measured by Digital High-Resolution PET Is a Promising Marker of Basal Forebrain Degeneration in the Lewy Body Disease Spectrum A Pilot Study
- 2020
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Ingår i: Clinical Nuclear Medicine. - : Ovid Technologies (Wolters Kluwer Health). - 0363-9762 .- 1536-0229. ; 45:4, s. 261-266
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Cognitive decline in diseases of the Lewy body spectrum (LBS) is linked to dysfunction/degeneration of the basal forebrain (BF). Assessment of glucose metabolism in the BF by FDG PET is hampered by the small size of the BF and limited spatial resolution of conventional PET. This pilot study tested the feasibility of assessing BF glucose metabolism by high-resolution digital PET (dPET). Patients and Methods The retrospective study included 12 LBS patients (61-86 years, 5 demented). Whole-brain stereotactic normalization to anatomical standard space was followed by local stereotactic normalization of a 7 x 7 x 7-cm(3) box around the BF to a custom-made 1 x 1 x 1-mm(3) FDG dPET template. FDG uptake was scaled voxelwise to mean FDG uptake in the pons. Scaled FDG uptake in the BF was compared between demented and nondemented LBS patients and tested for correlation with cortical FDG uptake. Results Scaled FDG uptake in the BF was significantly lower in demented compared with nondemented patients (1.14 +/- 0.09 vs 1.25 +/- 0.06, P = 0.031). Brain-wide voxel-based testing for correlations with scaled FDG uptake in the BF revealed a large cluster comprising medial and ventrolateral frontal cortex, anterior cingulate cortex, insular cortex, and striatum as well as smaller clusters in motor cortex and occipital cortex (P < 0.001, uncorrected). Conclusions These results suggest that dementia-associated BF degeneration in LBS can be sensitively measured as reduced BF FDG uptake on dPET. More accurate delineation of the BF based on individual high-resolution MRI might be useful to make optimal use of improved spatial resolution of dPET and to correct for possible disease- and age-dependent partial volume effects.
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