| 1. |
- Holmes, Michael V., et al.
(författare)
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Secretory Phospholipase A(2)-IIA and Cardiovascular Disease
- 2013
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Ingår i: Journal of the American College of Cardiology. - : Elsevier. - 0735-1097 .- 1558-3597. ; 62:21, s. 1966-1976
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Tidskriftsartikel (refereegranskat)abstract
- Objectives This study sought to investigate the role of secretory phospholipase A(2) (sPLA(2))-IIA in cardiovascular disease. less thanbrgreater than less thanbrgreater thanBackground Higher circulating levels of sPLA(2)-IIA mass or sPLA(2) enzyme activity have been associated with increased risk of cardiovascular events. However, it is not clear if this association is causal. A recent phase III clinical trial of an sPLA(2) inhibitor (varespladib) was stopped prematurely for lack of efficacy. less thanbrgreater than less thanbrgreater thanMethods We conducted a Mendelian randomization meta-analysis of 19 general population studies (8,021 incident, 7,513 prevalent major vascular events [MVE] in 74,683 individuals) and 10 acute coronary syndrome (ACS) cohorts (2,520 recurrent MVE in 18,355 individuals) using rs11573156, a variant in PLA2G2A encoding the sPLA(2)-IIA isoenzyme, as an instrumental variable. less thanbrgreater than less thanbrgreater thanResults PLA2G2A rs11573156 C allele associated with lower circulating sPLA(2)-IIA mass (38% to 44%) and sPLA(2) enzyme activity (3% to 23%) per C allele. The odds ratio (OR) for MVE per rs11573156 C allele was 1.02 (95% confidence interval [CI]: 0.98 to 1.06) in general populations and 0.96 (95% CI: 0.90 to 1.03) in ACS cohorts. In the general population studies, the OR derived from the genetic instrumental variable analysis for MVE for a 1-log unit lower sPLA(2)-IIA mass was 1.04 (95% CI: 0.96 to 1.13), and differed from the non-genetic observational estimate (OR: 0.69; 95% CI: 0.61 to 0.79). In the ACS cohorts, both the genetic instrumental variable and observational ORs showed a null association with MVE. Instrumental variable analysis failed to show associations between sPLA2 enzyme activity and MVE. less thanbrgreater than less thanbrgreater thanConclusions Reducing sPLA(2)-IIA mass is unlikely to be a useful therapeutic goal for preventing cardiovascular events.
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| 2. |
- Maasri, Alain, et al.
(författare)
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A global agenda for advancing freshwater biodiversity research
- 2022
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Ingår i: Ecology Letters. - : Wiley. - 1461-023X .- 1461-0248. ; 25:2, s. 255-263
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Tidskriftsartikel (refereegranskat)abstract
- Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation.
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| 3. |
- Albert, Christian, et al.
(författare)
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Neutrophil Gelatinase-Associated Lipocalin Measured on Clinical Laboratory Platforms for the Prediction of Acute Kidney Injury and the Associated Need for Dialysis Therapy : A Systematic Review and Meta-analysis
- 2020
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Ingår i: American Journal of Kidney Diseases. - : Elsevier BV. - 0272-6386 .- 1523-6838. ; 76:6, s. 826-
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Forskningsöversikt (refereegranskat)abstract
- Rationale & Objective: The usefulness of measures of neutrophil gelatinase-associated lipocalin (NGAL) in urine or plasma obtained on clinical laboratory platforms for predicting acute kidney injury (AKI) and AKI requiring dialysis (AKI-D) has not been fully evaluated. We sought to quantitatively summarize published data to evaluate the value of urinary and plasma NGAL for kidney risk prediction.Study Design: Literature-based meta-analysis and individual-study-data meta-analysis of diagnostic studies following PRISMA-IPD guidelines.Setting & Study Populations: Studies of adults investigating AKI, severe AKI, and AKI-D in the setting of cardiac surgery, intensive care, or emergency department care using either urinary or plasma NGAL measured on clinical laboratory platforms.Selection Criteria for Studies: PubMed, Web of Science, Cochrane Library, Scopus, and congress abstracts ever published through February 2020 reporting diagnostic test studies of NGAL measured on clinical laboratory platforms to predict AKI.Data Extraction: Individual-study-data meta analysis was accomplished by giving authors data specifications tailored to their studies and requesting standardized patient-level data analysis.Analytical Approach: Individual-study-data meta analysis used a bivariate time-to-event model for interval-censored data from which discriminative ability (AUC) was characterized. NGAL cutoff concentrations at 95% sensitivity, 95% specificity, and optimal sensitivity and specificity were also estimated. Models incorporated as confounders the clinical setting and use versus nonuse of urine output as a criterion for AKI. A literature-based meta-analysis was also performed for all published studies including those for which the authors were unable to provide individual-study data analyses.Results: We included 52 observational studies involving 13,040 patients. We analyzed 30 data sets for the individual-study-data meta-analysis. For AKI, severe AKI, and AKI-D, numbers of events were 837, 304, and 103 for analyses of urinary NGAL, respectively; these values were 705, 271, and 178 for analyses of plasma NGAL. Discriminative performance was similar in both meta-analyses. Individual-study-data meta-analysis AUCs for urinary NGAL were 0.75 (95% CI, 0.73-0.76) and 0.80 (95% CI, 0.79-0.81) for severe AKI and AKI-D, respectively; for plasma NGAL, the corresponding AUCs were 0.80 (95% CI, 0.790.81) and 0.86 (95% CI, 0.84-0.8 6). Cutoff concentrations at 95% specificity for urinary NGAL were >580 ng/mL with 27% sensitivity for severe AKI and >589 ng/mL with 24% sensitivity for AKI-D. Corresponding cutoffs for plasma NGAL were >364 ng/mL with 44% sensitivity and >546 ng/mL with 26% sensitivity, respectively.Limitations: Practice variability in initiation of dialysis. Imperfect harmonization of data across studies. Conclusions: Urinary and plasma NGAL concentrations may identify patients at high risk for AKI in clinical research and practice. The cutoff concentrations reported in this study require prospective evaluation.
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| 4. |
- Bentley, Blair P., et al.
(författare)
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Divergent sensory and immune gene evolution in sea turtles with contrasting demographic and life histories
- 2023
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences (PNAS). - 0027-8424 .- 1091-6490. ; 120:7
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Tidskriftsartikel (refereegranskat)abstract
- Sea turtles represent an ancient lineage of marine vertebrates that evolved from terrestrial ancestors over 100 Mya. The genomic basis of the unique physiological and ecological traits enabling these species to thrive in diverse marine habitats remains largely unknown. Additionally, many populations have drastically declined due to anthropogenic activities over the past two centuries, and their recovery is a high global conservation priority. We generated and analyzed high-quality reference genomes for the leatherback (Dermochelys coriacea) and green (Chelonia mydas) turtles, representing the two extant sea turtle families. These genomes are highly syntenic and homologous, but localized regions of noncollinearity were associated with higher copy numbers of immune, zinc-finger, and olfactory receptor (OR) genes in green turtles, with ORs related to waterborne odorants greatly expanded in green turtles. Our findings suggest that divergent evolution of these key gene families may underlie immunological and sensory adaptations assisting navigation, occupancy of neritic versus pelagic environments, and diet specialization. Reduced collinearity was especially prevalent in microchromosomes, with greater gene content, heterozygosity, and genetic distances between species, supporting their critical role in vertebrate evolutionary adaptation. Finally, diversity and demographic histories starkly contrasted between species, indicating that leatherback turtles have had a low yet stable effective population size, exhibit extremely low diversity compared with other reptiles, and harbor a higher genetic load compared with green turtles, reinforcing concern over their persistence under future climate scenarios. These genomes provide invaluable resources for advancing our understanding of evolution and conservation best practices in an imperiled vertebrate lineage.
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| 5. |
- Haase, Michael, et al.
(författare)
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The Outcome of Neutrophil Gelatinase-Associated Lipocalin-Positive Subclinical Acute Kidney Injury A Multicenter Pooled Analysis of Prospective Studies
- 2011
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Ingår i: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097 .- 1558-3597. ; 57:17, s. 1752-1761
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Tidskriftsartikel (refereegranskat)abstract
- Objectives The aim of this study was to test the hypothesis that, without diagnostic changes in serum creatinine, increased neutrophil gelatinase-associated lipocalin (NGAL) levels identify patients with subclinical acute kidney injury (AKI) and therefore worse prognosis. Background Neutrophil gelatinase-associated lipocalin detects subclinical AKI hours to days before increases in serum creatinine indicate manifest loss of renal function. Methods We analyzed pooled data from 2,322 critically ill patients with predominantly cardiorenal syndrome from 10 prospective observational studies of NGAL. We used the terms NGAL(-) or NGAL(+) according to study-specific NGAL cutoff for optimal AKI prediction and the terms sCREA(-) or sCREA(+) according to consensus diagnostic increases in serum creatinine defining AKI. A priori-defined outcomes included need for renal replacement therapy (primary endpoint), hospital mortality, their combination, and duration of stay in intensive care and in-hospital. Results Of study patients, 1,296 (55.8%) were NGAL(-)/sCREA(-), 445 (19.2%) were NGAL(+)/sCREA(-), 107 (4.6%) were NGAL(-)/sCREA(+), and 474 (20.4%) were NGAL(+)/sCREA(+). According to the 4 study groups, there was a stepwise increase in subsequent renal replacement therapy initiation-NGAL(-)/sCREA(-): 0.0015% versus NGAL(+)/sCREA(-): 2.5% (odds ratio: 16.4, 95% confidence interval: 3.6 to 76.9, p < 0.001), NGAL(-)/sCREA(+): 7.5%, and NGAL(+)/sCREA(+): 8.0%, respectively, hospital mortality (4.8%, 12.4%, 8.4%, 14.7%, respectively) and their combination (4-group comparisons: all p < 0.001). There was a similar and consistent progressive increase in median number of intensive care and in-hospital days with increasing biomarker positivity: NGAL(-)/sCREA(-): 4.2 and 8.8 days; NGAL(+)/sCREA(-): 7.1 and 17.0 days; NGAL(-)/sCREA(+): 6.5 and 17.8 days; NGAL(+)/sCREA(+): 9.0 and 21.9 days; 4-group comparisons: p = 0.003 and p = 0.040, respectively. Urine and plasma NGAL indicated a similar outcome pattern. Conclusions In the absence of diagnostic increases in serum creatinine, NGAL detects patients with likely subclinical AKI who have an increased risk of adverse outcomes. The concept and definition of AKI might need re-assessment.
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| 6. |
- Lembrechts, Jonas J., et al.
(författare)
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SoilTemp : A global database of near-surface temperature
- 2020
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 26:11, s. 6616-6629
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Tidskriftsartikel (refereegranskat)abstract
- Current analyses and predictions of spatially explicit patterns and processes in ecology most often rely on climate data interpolated from standardized weather stations. This interpolated climate data represents long-term average thermal conditions at coarse spatial resolutions only. Hence, many climate-forcing factors that operate at fine spatiotemporal resolutions are overlooked. This is particularly important in relation to effects of observation height (e.g. vegetation, snow and soil characteristics) and in habitats varying in their exposure to radiation, moisture and wind (e.g. topography, radiative forcing or cold-air pooling). Since organisms living close to the ground relate more strongly to these microclimatic conditions than to free-air temperatures, microclimatic ground and near-surface data are needed to provide realistic forecasts of the fate of such organisms under anthropogenic climate change, as well as of the functioning of the ecosystems they live in. To fill this critical gap, we highlight a call for temperature time series submissions to SoilTemp, a geospatial database initiative compiling soil and near-surface temperature data from all over the world. Currently, this database contains time series from 7,538 temperature sensors from 51 countries across all key biomes. The database will pave the way toward an improved global understanding of microclimate and bridge the gap between the available climate data and the climate at fine spatiotemporal resolutions relevant to most organisms and ecosystem processes.
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| 7. |
- Pivarcsi, Andor, et al.
(författare)
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Tumor immune escape by the loss of homeostatic chemokine expression.
- 2007
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 104:48, s. 19055-60
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Tidskriftsartikel (refereegranskat)abstract
- The novel keratinocyte-specific chemokine CCL27 plays a critical role in the organization of skin-associated immune responses by regulating T cell homing under homeostatic and inflammatory conditions. Here we demonstrate that human keratinocyte-derived skin tumors may evade T cell-mediated antitumor immune responses by down-regulating the expression of CCL27 through the activation of epidermal growth factor receptor (EGFR)-Ras-MAPK-signaling pathways. Compared with healthy skin, CCL27 mRNA and protein expression was progressively lost in transformed keratinocytes of actinic keratoses and basal and squamous cell carcinomas. In vivo, precancerous skin lesions as well as cutaneous carcinomas showed significantly elevated levels of phosphorylated ERK compared with normal skin, suggesting the activation of EGFR-Ras signaling pathways in keratinocyte-derived malignancies. In vitro, exogenous stimulation of the EGFR-Ras signaling pathway through EGF or transfection of the dominant-active form of the Ras oncogene (H-RasV12) suppressed whereas an EGFR tyrosine kinase inhibitor increased CCL27 mRNA and protein production in keratinocytes. In mice, neutralization of CCL27 led to decreased leukocyte recruitment to cutaneous tumor sites and significantly enhanced primary tumor growth. Collectively, our data identify a mechanism of skin tumors to evade host antitumor immune responses.
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| 8. |
- Arge, Tummas Napoleon, et al.
(författare)
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Measuring structural inhomogeneity of a helical conjugated polymer at high pressure and temperature
- 2019
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Ingår i: Journal of Polymer Science, Part B: Polymer Physics. - : Wiley. - 0887-6266. ; 57:7, s. 392-396
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Tidskriftsartikel (refereegranskat)abstract
- We report on X-ray scattering measurements of helical poly[9,9-bis(2-ethylhexyl)-fluorene-2,7-diyl] by mapping the sample with 10 μm spatial resolution from 0.3 GPa to 36 GPa. We follow the strongest 00l reflection, which moves toward higher scattering angles with pressure indicating planarization of helical polyfluorene. Lateral inhomogeneity is increased for >10 GPa concomitant with the solidification of the pressure transmitting medium (a 4:1 mixture of methanol and ethanol). We also follow the 00l reflection with increasing temperature at the constant pressure of 4.3 GPa in neon. We observe a sharp shift toward higher scattering angles indicative of a phase transition at 167–176 °C.
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| 9. |
- Baker, Nathan Jay, et al.
(författare)
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Multidecadal changes in functional diversity lag behind the recovery of taxonomic diversity
- 2021
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Ingår i: Ecology and Evolution. - : John Wiley & Sons. - 2045-7758. ; 11:23, s. 17471-17484
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Tidskriftsartikel (refereegranskat)abstract
- While there has been increasing interest in how taxonomic diversity is changing over time, less is known about how long-term taxonomic changes may affect ecosystem functioning and resilience. Exploring long-term patterns of functional diversity can provide key insights into the capacity of a community to carry out ecological processes and the redundancy of species’ roles. We focus on a protected freshwater system located in a national park in southeast Germany. We use a high-resolution benthic macroinvertebrate dataset spanning 32 years (1983–2014) and test whether changes in functional diversity are reflected in taxonomic diversity using a multidimensional trait-based approach and regression analyses. Specifically, we asked: (i) How has functional diversity changed over time? (ii) How functionally distinct are the community's taxa? (iii) Are changes in functional diversity concurrent with taxonomic diversity? And (iv) what is the extent of community functional redundancy? Resultant from acidification mitigation, macroinvertebrate taxonomic diversity increased over the study period. Recovery of functional diversity was less pronounced, lagging behind responses of taxonomic diversity. Over multidecadal timescales, the macroinvertebrate community has become more homogenous with a high degree of functional redundancy, despite being isolated from direct anthropogenic activity. While taxonomic diversity increased over time, functional diversity has yet to catch up. These results demonstrate that anthropogenic pressures can remain a threat to biotic communities even in protected areas. The differences in taxonomic and functional recovery processes highlight the need to incorporate functional traits in assessments of biodiversity responses to global change.
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| 10. |
- Baker, Nathan Jay, et al.
(författare)
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Recovery from air pollution and subsequent acidification masks the effects of climate change on a freshwater macroinvertebrate community
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 758
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Tidskriftsartikel (refereegranskat)abstract
- Freshwater ecosystems are dynamic, complex systems with a multitude of physical and ecological processes and stressors which drive fluctuations on the community-level. Disentangling the effects of different processes and stressors is challenging due to their interconnected nature. However, as protected areas (i.e. national parks) are less anthropogenically impacted, they are ideal for investigating single stressors. We focus on the Bavarian Forest National Park, a Long-Term Ecological Research (LTER) site in Germany, where the major stressors are climate warming, air pollution (i.e. acidification) and bark beetle infestations. We investigated the effects of these stressors on freshwater macroinvertebrates using comprehensive long-term (1983–2014) datasets comprising high-resolution macroinvertebrate and physico-chemical data from a near-natural stream. Macroinvertebrate communities have undergone substantial changes over the past 32 years, highlighted by increases in overall community abundance (+173%) and richness (+51.6%) as well as taxonomic restructuring driven by a disproportional increase of dipterans. Prior to the year 2000, regression analyses revealed a decline in sulphate deposition and subsequent recovery from historical acidification as potential drivers of the increases in abundance and richness rather than to increases in water temperature (1.5 °C overall increase). Post 2000, however, alterations to nutrient cycling caused by bark beetle infestations coupled with warming temperatures were correlated to taxonomic restructuring and disproportional increases of dipterans at the expense of sensitive taxa such as plecopterans and trichopterans. Our results highlight the challenges when investigating the effects of climate change within a multi-stressor context. Even in conservation areas, recovery from previous disturbance might mask the effects of ongoing disturbances like climate change. Overall, we observed strong community restructuring, demonstrating that stenothermal headwater communities face additional stress due to emerging competition with tolerant taxa. Conservation efforts should consider the temporal variability of communities and their recovery from disturbances to adequately identify species vulnerable to local or widespread extinction.
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| 11. |
- Baranov, Viktor, et al.
(författare)
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Complex and nonlinear climate-driven changes in freshwater insect communities over 42 years
- 2020
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Ingår i: Conservation Biology. - : John Wiley & Sons. - 0888-8892 .- 1523-1739. ; 34:5, s. 1241-1251
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Tidskriftsartikel (refereegranskat)abstract
- The ongoing biodiversity crisis becomes evident in the widely observed decline in abundance and diversity of species, profound changes in community structure, and shifts in species' phenology. Insects are among the most affected groups, with documented decreases in abundance up to 76% in the last 25–30 years in some terrestrial ecosystems. Identifying the underlying drivers is a major obstacle as most ecosystems are affected by multiple stressors simultaneously and in situ measurements of environmental variables are often missing. In our study, we investigated a headwater stream belonging to the most common stream type in Germany located in a nature reserve with no major anthropogenic impacts except climate change. We used the most comprehensive quantitative long‐term data set on aquatic insects available, which includes weekly measurements of species‐level insect abundance, daily water temperature and stream discharge as well as measurements of additional physicochemical variables for a 42‐year period (1969–2010). Overall, water temperature increased by 1.88°C and discharge patterns changed significantly. These changes were accompanied by an 81.6% decline in insect abundance, but an increase in richness (+8.5%), Shannon diversity (+22.7%), evenness (+22.4%), and interannual turnover (+34%). Moreover, the community's trophic structure and phenology changed: the duration of emergence increased by 15.2 days, whereas the peak of emergence moved 13.4 days earlier. Additionally, we observed short‐term fluctuations (<5 years) in almost all metrics as well as complex and nonlinear responses of the community toward climate change that would have been missed by simply using snapshot data or shorter time series. Our results indicate that climate change has already altered biotic communities severely even in protected areas, where no other interacting stressors (pollution, habitat fragmentation, etc.) are present. This is a striking example of the scientific value of comprehensive long‐term data in capturing the complex responses of communities toward climate change.
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| 12. |
- Biró, Péter, et al.
(författare)
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Building Kindey Exchange Programmes in Europe - An Overview of Exchange Practice and Activities
- 2019
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Ingår i: Transplantation. - 1534-6080. ; 103:7, s. 1514-1522
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Tidskriftsartikel (refereegranskat)abstract
- Bakgrund: Considerable differences exist among the living donor Kidney Exchange Programmes (KEPs) that are in use and being built in Europe, contributing to a variation in the number of living donor transplants [6]. Efforts of European KEPs to exchange (best) practices and share approaches to address challenges have, however, been limited.Methods: Experts from 23 European countries, collaborating on the ENCKEP COST Action, developed a questionnaire to collect detailed information on the functioning of all existing KEPs in Europe, as well as their opportunities and challenges. Following a comparative analysis, results were synthesised and interpreted by the same experts.Results: The practices, opportunities and challenges reported by 17 European countries reveal that some of the 10 operating programmes are mature, while others are in earlier stages of development. Over 1300 transplants were performed through existing KEPs up to the end of 2016, providing approximately 8% of their countries’ living kidney donations in 2015. All countries report challenges to either initiating KEPs or increasing volumes. Some challenges are shared, whilst others differ because of differences in context (eg, country size, effectiveness of deceased donor programme) and ethical and legal considerations (eg, regarding living donation as such, nonrelated donors, and altruistic donation). Transnational initiatives have started in Central Europe, Scandinavia, and Southern Europe.Conclusions: Exchange of best practices and shared advancement of national programmes to address existing challenges, aided by transnational exchanges, may substantially improve access to the most (cost) effective treatment for the increasing number of patients suffering from kidney disease.
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| 13. |
- Biró, Péter, et al.
(författare)
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Modelling and optimisation in European Kidney Exchange Programmes
- 2021
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Ingår i: European Journal of Operational Research. - : Elsevier BV. - 0377-2217. ; 291:2, s. 447-456
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Tidskriftsartikel (refereegranskat)abstract
- The complex multi-criteria optimisation problems arising in Kidney Exchange Programmes have received considerable attention both in practice and in the scientific literature. Whereas theoretical advancements are well reviewed and synthesised, this is not the case for practice. We present a synthesis of models and methods applied in present European Kidney Exchange Programmes, which is based on detailed descriptions we created for this purpose. Most descriptions address national programmes, yet we also present findings on emerging cross-national programmes. The synthesis provides a systematic and detailed description of the models and methods the programmes use, revealing important commonalities as well as considerable variation among them. Rather than distilling a single best practice from these results, we find that the variation in models and methods arises because of variation in country characteristics, policies, and ethics. The synthesised state of the art may benefit future national and cross-national initiatives and direct future theoretical contributions within and across the boundaries of the Operations Research discipline.
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| 14. |
- Biurrun, Idoia, et al.
(författare)
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Benchmarking plant diversity of Palaearctic grasslands and other open habitats
- 2021
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Ingår i: Journal of Vegetation Science. - Oxford : John Wiley & Sons. - 1100-9233 .- 1654-1103. ; 32:4
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Tidskriftsartikel (refereegranskat)abstract
- Journal of Vegetation Science published by John Wiley & Sons Ltd on behalf of International Association for Vegetation Science.Aims: Understanding fine-grain diversity patterns across large spatial extents is fundamental for macroecological research and biodiversity conservation. Using the GrassPlot database, we provide benchmarks of fine-grain richness values of Palaearctic open habitats for vascular plants, bryophytes, lichens and complete vegetation (i.e., the sum of the former three groups). Location: Palaearctic biogeographic realm. Methods: We used 126,524 plots of eight standard grain sizes from the GrassPlot database: 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 and 1,000 m2 and calculated the mean richness and standard deviations, as well as maximum, minimum, median, and first and third quartiles for each combination of grain size, taxonomic group, biome, region, vegetation type and phytosociological class. Results: Patterns of plant diversity in vegetation types and biomes differ across grain sizes and taxonomic groups. Overall, secondary (mostly semi-natural) grasslands and natural grasslands are the richest vegetation type. The open-access file ”GrassPlot Diversity Benchmarks” and the web tool “GrassPlot Diversity Explorer” are now available online (https://edgg.org/databases/GrasslandDiversityExplorer) and provide more insights into species richness patterns in the Palaearctic open habitats. Conclusions: The GrassPlot Diversity Benchmarks provide high-quality data on species richness in open habitat types across the Palaearctic. These benchmark data can be used in vegetation ecology, macroecology, biodiversity conservation and data quality checking. While the amount of data in the underlying GrassPlot database and their spatial coverage are smaller than in other extensive vegetation-plot databases, species recordings in GrassPlot are on average more complete, making it a valuable complementary data source in macroecology. © 2021 The Authors.
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| 15. |
- Brugger, Karolina, et al.
(författare)
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Nanofabricated atom optics : atom chips
- 2000
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Ingår i: Journal of Modern Optics. - : Taylor & Francis. ; 47:14-15, s. 2789-2809
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Tidskriftsartikel (refereegranskat)
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| 16. |
- Goh, Gerald, et al.
(författare)
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Recurrent activating mutation in PRKACA in cortisol-producing adrenal tumors
- 2014
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Ingår i: Nature Genetics. - : Springer Science and Business Media LLC. - 1061-4036 .- 1546-1718. ; 46:6, s. 613-617
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Tidskriftsartikel (refereegranskat)abstract
- Adrenal tumors autonomously producing cortisol cause Cushing's syndrome1, 2, 3, 4. We performed exome sequencing of 25 tumor-normal pairs and identified 2 subgroups. Eight tumors (including three carcinomas) had many somatic copy number variants (CNVs) with frequent deletion of CDC42 and CDKN2A, amplification of 5q31.2 and protein-altering mutations in TP53 and RB1. Seventeen tumors (all adenomas) had no somatic CNVs or TP53 or RB1 mutations. Six of these had known gain-of-function mutations in CTNNB1 (β-catenin)5, 6 or GNAS (Gαs)7, 8. Six others had somatic mutations in PRKACA (protein kinase A (PKA) catalytic subunit) resulting in a p.Leu206Arg substitution. Further sequencing identified this mutation in 13 of 63 tumors (35% of adenomas with overt Cushing's syndrome). PRKACA, GNAS and CTNNB1 mutations were mutually exclusive. Leu206 directly interacts with the regulatory subunit of PKA, PRKAR1A9, 10. Leu206Arg PRKACA loses PRKAR1A binding, increasing the phosphorylation of downstream targets. PKA activity induces cortisol production and cell proliferation11, 12, 13, 14, 15, providing a mechanism for tumor development. These findings define distinct mechanisms underlying adrenal cortisol-producing tumors.
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| 17. |
- Haase, Peter, et al.
(författare)
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A method for the reintroduction of entire benthic invertebrate communities in formerly degraded streams
- 2019
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Ingår i: Limnologica. - : Elsevier. - 0075-9511 .- 1873-5851. ; 77
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Tidskriftsartikel (refereegranskat)abstract
- Reintroduction is a commonly used tool in wildlife conservation. Although freshwater ecosystems are among the most threatened worldwide, reintroductions of entire benthic invertebrate communities have never been reported before. Here, for the first time, we developed a comprehensive method for the reintroduction of entire communities in formerly degraded streams that describes the selection of donor and recipient streams, the transfer of specimens, mortality rates, and a monitoring scheme. The stream selection procedure of the new method is based on widely available environmental variables and richness metrics that are regularly monitored by water authorities to fulfill the requirements of water policy frameworks (e.g. EU WFD). The sampling and transfer of specimens is also based on common and simply applicable methods (i.e. kick sampling). For each recipient stream, three donor streams were selected with a complementary set of reference species missing at the recipient stream. The sampling at each donor stream was done six times a year to cover different seasons and life stages. We applied our method to one stream (10 km2) and one river (1608 km2) in central Germany. In total, we transferred 325,197 and 401,233 specimens from three different donor streams, including 45 (28,682 specimens) and 50 (47,716 specimens) missing reference taxa into each recipient stream and river, respectively. Average mortality rates varied between 0.97% for all specimens and 1.72% for reference specimens. We recommend a post-reintroduction monitoring that includes new methods, i.e. environmental DNA and high throughput sequencing. Our proposed reintroduction method is based on commonly used variables, metrics and sampling techniques. Accordingly, this method requires only minor modifications to become applicable in other countries. The simultaneous reintroduction of a large number of reference taxa will increase the likelihood to reestablish near-natural benthic invertebrate communities in formerly degraded streams. This may increase the public and political acceptance of costly river restoration projects that so far, do not often reach a good ecological status even after decades, due to a large-scale depletion of potential source populations. Our method will help in the reintroduction of reference species in restored streams where natural recolonization is not possible.
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| 18. |
- Haase, Peter, et al.
(författare)
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Moderate warming over the past 25 years has already reorganized stream invertebrate communities
- 2019
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 658, s. 1531-1538
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Tidskriftsartikel (refereegranskat)abstract
- Climate warming often results in species range shifts, biodiversity loss and accumulated climatic debts of biota (i.e. slower changes in biota than in temperature). Here, we analyzed the changes in community composition and temperature signature of stream invertebrate communities over 25 years (1990-€“2014), based on a large set of samples (n = 3782) over large elevation, latitudinal and longitudinal gradients in central Europe. Although warming was moderate (average 0.5°C), we found a strong reorganization of stream invertebrate communities. Total abundance (+35.9%) and richness (+39.2%) significantly increased. The share of abundance (TA) and taxonomic richness (TR) of warm-dwelling taxa (TA: +73.2%; TR: +60.2%) and medium-temperature-dwelling taxa (TA: +0.4%; TR: +5.8%) increased too, while cold-dwelling taxa declined (TA: -61.5%; TR: -ˆ’47.3%). The community temperature index, representing the temperature signature of stream invertebrate communities, increased at a similar pace to physical temperature, indicating a thermophilization of the communities and, for the first time, no climatic debt. The strongest changes occurred along the altitudinal gradient, suggesting that stream invertebrates use the spatial configuration of river networks to track their temperature niche uphill. Yet, this may soon come to an end due to the summit trap effect. Our results indicate an ongoing process of replacement of cold-adapted species by thermophilic species at only 0.5 °C warming, which is particularly alarming in the light of the more drastic climate warming projected for coming decades.
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| 19. |
- Haubrock, Phillip J., et al.
(författare)
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Do changes in temperature affect EU Water Framework Directive compliant assessment results of central European streams?
- 2020
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Ingår i: Environmental Sciences Europe. - : Springer. - 2190-4707 .- 2190-4715. ; 32
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Tidskriftsartikel (refereegranskat)abstract
- Background: Benthic invertebrate communities are an integral and longstanding component of stream biomonitoring. However, multiple stressors driven by global change threaten benthic invertebrate communities. In particular, climate warming is expected to disrupt freshwater ecosystems. While an increasing number of studies have shown changes in benthic invertebrate community composition in response to climate warming, the effect on stream assessments has rarely been investigated. As several community composition metrics are also used in stream assessments, we predicted that climate warming would worsen stream assessment results. Therefore, we used a comprehensive data set of 2865 benthic invertebrate samples taken between 2000 and 2014 from small central European low mountain streams. We examined the effects of changes in temperature on common community and stream assessment metrics. We used 31 metrics covering composition, richness, tolerance and function of communities, of which many are used in various stream assessment schemes.Results: Against our expectations, we identified a decreasing air temperature trend of − 0.18 °C over 15 years. This trend was accompanied by significant changes in community composition, for example, increases in species richness and decreases in the community temperature index (CTI). Further, we identified slight concomitant improvements of various globally used stream quality assessment metrics, such as a decreasing saprobic index and an increasing BMWP.Conclusions: While temperature increased by + 0.9 °C during the past 30 years (1985–2014), our 15-year study period (2000–2014) showed a decrease by − 0.18 °C. Therefore, we regard the concomitant improvement in several assessment metrics as a recovery from prior increasing temperatures. In turn, we assume that increases in water temperature will lead to opposite effects and therefore cause declining assessment results. Water managers should be aware of this linkage that in turn could provide a chance to mitigate the effects of global warming by, for example, planting trees along the rivers and the removal of artificial barriers to increase current velocity to minimize a warming effect.
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| 20. |
- Haubrock, Phillip J., et al.
(författare)
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Multidecadal data indicate increase of aquatic insects in Central European streams
- 2023
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 879
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, declining insect biodiversity has sparked interest among scientists and drawn the attention of society and politicians. However, our understanding of the extent of this decline is incomplete, particularly for freshwater insects that provide a key trophic link between aquatic and terrestrial ecosystems, but that are also especially vulnerable to climate change. To investigate the response of freshwater insects to climate change, we quantified shifts in insect abundance and diversity across 7264 samples covering Central Europe during 1990–2018 and related these changes to annual data on temperature and precipitation. We observed both increases in richness (10.6 %) and abundance (9.5 %) of freshwater insects over the past three decades. These changes were related to increases in summer temperature and summer precipitation, which had negative effects on species richness, and to increases in winter temperature and precipitation, which had positive effects. Further we found that increased temperature was generally related to increased abundance, whereas increased precipitation was associated with declines, thus highlighting the particularly varying impacts on differing insect orders. Given that freshwater insects have been more severely affected by global change than marine and terrestrial species, the observed increases are a positive sign, but the overall situation of freshwater invertebrates is still critical.
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| 21. |
- Haubrock, Phillip J., et al.
(författare)
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Two centuries for an almost complete community turnover from native to non-native species in a riverine ecosystem
- 2021
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Ingår i: Global Change Biology. - : John Wiley & Sons. - 1354-1013 .- 1365-2486. ; 27:3, s. 606-623
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Tidskriftsartikel (refereegranskat)abstract
- Non-native species introductions affect freshwater communities by changing community compositions, functional roles, trait occurrences and ecological niche spaces. Reconstructing such changes over long periods is difficult due to limited data availability. We collected information spanning 215 years on fish and selected macroinvertebrate groups (Mollusca and Crustacea) in the inner-Florentine stretch of the Arno River (Italy) and associated water grid, to investigate temporal changes. We identified an almost complete turnover from native to non-native fish (1800: 92% native; 2015: 94% non-native species) and macroinvertebrate species (1800: 100% native; 2015: 70% non-native species). Non-native fish species were observed similar to 50 years earlier compared to macroinvertebrate species, indicating phased invasion processes. In contrast, alpha-diversity of both communities increased significantly following a linear pattern. Separate analyses of changes in alpha-diversities for native and non-native species of both fish and macroinvertebrates were nonlinear. Functional richness and divergence of fish and macroinvertebrate communities decreased non-significantly, as the loss of native species was compensated by non-native species. Introductions of non-native fish and macroinvertebrate species occurred outside the niche space of native species. Native and non-native fish species exhibited greater overlap in niche space over time (62%-68%) and non-native species eventually replaced native species. Native and non-native macroinvertebrate niches overlapped to a lesser extent (15%-30%), with non-natives occupying mostly unoccupied niche space. These temporal changes in niche spaces of both biotic groups are a direct response to the observed changes in alpha-diversity and species turnover. These changes are potentially driven by deteriorations in hydromorphology as indicated by alterations in trait modalities. Additionally, we identified that angling played a considerable role for fish introductions. Our results support previous findings that the community turnover from native to non-native species can be facilitated by, for example, deteriorating environmental conditions and that variations in communities are multifaceted requiring more indicators than single metrics.
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| 22. |
- Jourdan, Jonas, et al.
(författare)
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Effects of changing climate on European stream invertebrate communities : A long-term data analysis
- 2018
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 621, s. 588-599
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Tidskriftsartikel (refereegranskat)abstract
- Long-term observations on riverine benthic invertebrate communities enable assessments of the potential impacts of global change on stream ecosystems. Besides increasing average temperatures, many studies predict greater temperature extremes and intense precipitation events as a consequence of climate change. In this study we examined long-term observation data (10–32years) of 26 streams and rivers from four ecoregions in the European Long-Term Ecological Research (LTER) network, to investigate invertebrate community responses to changing climatic conditions. We used functional trait and multi-taxonomic analyses and combined examinations of general long-term changes in communities with detailed analyses of the impact of different climatic drivers (i.e., various temperature and precipitation variables) by focusing on the response of communities to climatic conditions of the previous year. Taxa and ecoregions differed substantially in their response to climate change conditions. We did not observe any trend of changes in total taxonomic richness or overall abundance over time or with increasing temperatures, which reflects a compensatory turnover in the composition of communities; sensitive Plecoptera decreased in response to warmer years and Ephemeroptera increased in northern regions. Invasive species increased with an increasing number of extreme days which also caused an apparent upstream community movement. The observed changes in functional feeding group diversity indicate that climate change may be associated with changes in trophic interactions within aquatic food webs. These findings highlight the vulnerability of riverine ecosystems to climate change and emphasize the need to further explore the interactive effects of climate change variables with other local stressors to develop appropriate conservation measures.
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| 23. |
- Knaapila, Matti, et al.
(författare)
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Measuring Structural Inhomogeneity of Conjugated Polymer at High Pressures up to 30 GPa
- 2013
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Ingår i: Macromolecules. - : American Chemical Society (ACS). - 0024-9297 .- 1520-5835. ; 46:20, s. 8284-8288
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Tidskriftsartikel (refereegranskat)abstract
- We present X-ray scattering data from helical poly[9,9-bis(2-ethylhexyl)-fluorene-2,7-diyl] by mapping the sample with 10 mu m spatial resolution at pressures up to 31 GPa. Neon is used as pressure transmitting medium. Reduction of torsion angle between adjacent repeats is observed during compression and found to be reversible upon decompression. Chain conformation does not depend on lateral position of sample in the pressure range from 1 to 7 GPa but depends significantly when pressure is increased from 7 to 31 GPa. Crystallite orientation does not depend on pressure or lateral position. The radiation damage is studied optically ex situ and proved to be insignificant.
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| 24. |
- Krüger, Peter, et al.
(författare)
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Quantum Information Processing with Neutral Atoms on Atom Chips
- 2005. - 2
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Ingår i: Quantum Information Processing. - : Wiley-VCH Verlagsgesellschaft. - 9783527606009 ; , s. 298-311
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter contains sections titled: * Introduction * The Atom Chip * Combined Magneto-Electric Traps * RF-induced Adiabatic Potentials for Manipulating Atoms * Imperfections in the Atom Chip: Disorder Potentials * The Qubit * Entangling Qubits * Quantum Gate via Cold Controlled Collisions * Motional Qubit Gates with Controlled Collisions * Input/Output * Qubit Detection * Quantum Input/Output * Noise and Decoherence * Summary and Conclusion * References
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| 25. |
- Lykke Sørensen, Jens Fyhn, et al.
(författare)
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Do rural school closures lead to local population decline?
- 2021
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Ingår i: Journal of Rural Studies. - : Elsevier. - 0743-0167 .- 1873-1392. ; 87, s. 226-235
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Tidskriftsartikel (refereegranskat)abstract
- In Denmark, many rural schools have been closed since 2000. These school closures have often resulted in heated debates between local politicians and the local population. Locals have feared that closing their school would have adverse effects and lead to local population decline. Meanwhile, previous research has found mixed evidence on the population effect of rural school closures. The aim of this paper is to contribute to the existing literature by looking at the case of Denmark. The paper analyses the local population effects of the simultaneous closure of eight village schools in 2011 in the same peripheral municipality in Denmark. The case study offers a quasi-experimental setting, and the population effects are estimated through an ordinary and a flexible difference-in-differences (DiD) analysis. Overall, the results show clear evidence of a negative population effect of rural school closures. The ordinary DiD analysis shows a population decline of 7.6 percentage points during the 10-year post-closure period. The flexible DiD analysis points to long-term effects, as the population decline first becomes statistically significant from the sixth year following the closures and onwards. To qualify the results of the econometric tests, we report findings from interviews with local people carried out in 2015 in four of the eight rural communities. Among other things, findings from interviews point to lock-in effects in terms of social capital and housing markets, which helps to understand the dominance of long-term population effects from school closures.
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| 26. |
- Manfrin, Alessandro, et al.
(författare)
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Taxonomic and functional reorganization in Central European stream macroinvertebrate communities over 25 years
- 2023
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 889
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Tidskriftsartikel (refereegranskat)abstract
- Climate warming can lead to a replacement of species that favour cold temperatures by species that favour warm temperatures. However, the implications of such thermic shifts for the functioning of ecosystems remain poorly understood. Here, we used stream macroinvertebrate biological and ecological traits to quantify the relative contribution of cold, intermediate and warm temperature-adapted taxa to changes in community functional diversity (FD) using a dataset of 3781 samples collected in Central Europe over 25 years, from 1990 to 2014.Our analyses indicated that functional diversity of stream macroinvertebrate communities increased over the study period. This gain was driven by a net 39 % increase in the richness of taxa that favour intermediate temperatures, which comprise the highest share in the community, and to a 97 % increase in the richness of taxa that favour warm temperatures. These warm temperature-adapted taxa displayed a distinct and more diverse suite of functional traits compared to the cold temperature-adapted group and thus contributed disproportionately to local FD on a per-taxon basis. At the same time, taxonomic beta-diversity declined significantly within each thermal group, in association with increasing local taxon richness.This study shows that over recent decades, small low-mountain streams in Central Europe have experienced a process of thermophilization and increasing functional diversity at local scales. However, a progressive homogenisation occurred at the regional scale, with communities converging towards similar taxonomic composition. As the reported increase in local functional diversity can be attributed mostly to the intermediate temperature-adapted taxa and a few expanding warm temperature-adapted taxa, these patterns could mask more subtle loss of sensitive cold temperature-adapted taxa with irreplaceable functional traits. In light of increasing climate warming, preservation of cold habitat refuges, should be considered a priority in river conservation.
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| 27. |
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| 28. |
- Perner, Anders, et al.
(författare)
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Hydroxyethyl Starch 130/0.4 versus Ringer's Acetate in Severe Sepsis
- 2012
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Ingår i: New England Journal of Medicine. - 0028-4793 .- 1533-4406. ; 367:2, s. 124-134
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND Hydroxyethyl starch (HES) 130/0.4 is widely used for fluid resuscitation in intensive care units (ICUs), but its safety and efficacy have not been established in patients with severe sepsis. METHODS In this multicenter, parallel-group, blinded trial, we randomly assigned patients with severe sepsis to fluid resuscitation in the ICU with either 6% HES 130/0.4 or Ringer's acetate at a dose of up to 33 ml per kilogram of ideal body weight per day. The primary outcome measure was either death or end-stage kidney failure (dependence on dialysis) at 90 days after randomization. RESULTS Of the 804 patients who underwent randomization, 798 were included in the modified intention-to-treat population. The two intervention groups had similar baseline characteristics. At 90 days after randomization, 201 of 398 patients (51%) assigned to HES 130/0.4 had died, as compared with 172 of 400 patients (43%) assigned to Ringer's acetate (relative risk, 1.17; 95% confidence interval [CI], 1.01 to 1.36; P=0.03); 1 patient in each group had end-stage kidney failure. In the 90-day period, 87 patients (22%) assigned to HES 130/0.4 were treated with renal-replacement therapy versus 65 patients (16%) assigned to Ringer's acetate (relative risk, 1.35; 95% CI, 1.01 to 1.80; P=0.04), and 38 patients (10%) and 25 patients (6%), respectively, had severe bleeding (relative risk, 1.52; 95% CI, 0.94 to 2.48; P=0.09). The results were supported by multivariate analyses, with adjustment for known risk factors for death or acute kidney injury at baseline. CONCLUSIONS Patients with severe sepsis assigned to fluid resuscitation with HES 130/0.4 had an increased risk of death at day 90 and were more likely to require renal-replacement therapy, as compared with those receiving Ringer's acetate.
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| 29. |
- Pilotto, Francesca, et al.
(författare)
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Decline in niche specialization and trait β-diversity in benthic invertebrate communities of Central European low-mountain streams over 25 years
- 2022
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 810
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Tidskriftsartikel (refereegranskat)abstract
- Biotic homogenization is one of the key aspects of the current biodiversity crisis. Here we analyzed the trends of three facets of niche homogenization, i.e. niche specialization, trait α-diversity and spatial β-diversity, over a period of 25 years (1990–2014) using a large dataset of 3782 stream benthic invertebrate samples collected from central European low-mountain streams. We studied a set of traits describing the ecological niche of species and their functions: body size, feeding groups, substrate preferences, flow preferences, stream zonation preferences and saprobity. Trait composition changed significantly during the study period, and we identified an overall increase in niche homogenization. Specifically, community niche specialization significantly decreased by 20.3% over the 25-year period, with declines ranging from −16.0 to −40.9% for zonation-, flow-, substrate-preferences, body size and feeding traits. Trait diversity did not change significantly, although we recorded significant decreases by −14.2% and −10.2% for flow- and substrate-preference and increases by 5.8% and 22.6% for feeding traits and zonation preference over the study period. Trait spatial β-diversity significantly decreased by −53.0%, with substrate-preference, feeding groups and flow-preference traits declining from −61.9% to −75.3% over the study period. This increased niche homogenization is likely driven by the increase of down-stream typical taxa, which are favored by warming temperatures. Further, it is in apparent contradiction with the recorded increase in abundance (+35.9%) and taxonomic richness (+39.2%) over the same period. Even such increases do not safeguard communities from undergoing niche homogenization, indicating that recovery processes may differ with regard to community taxonomic composition and traits. Our results emphasize the complexity of community responses to global change and warrant caution when founding conclusions based solely on single community metrics.
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| 30. |
- Pilotto, Francesca, et al.
(författare)
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Diverging response patterns of terrestrial and aquatic species to hydromorphological restoration
- 2019
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Ingår i: Conservation Biology. - : John Wiley & Sons. - 0888-8892 .- 1523-1739. ; 33:1, s. 132-141
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Tidskriftsartikel (refereegranskat)abstract
- Although experiences with ecological restoration continue to accumulate, the effectiveness of restoration for biota remains debated. We complemented a traditional taxonomic analysis approach with information on 56 species traits to uncover the responses of 3 aquatic (fish, macroinvertebrates, macrophytes) and 2 terrestrial (carabid beetles, floodplain vegetation) biotic groups to 43 hydromorphological river restoration projects in Germany. All taxonomic groups responded positively to restoration, as shown by increased taxonomic richness (10–164%) and trait diversity (habitat, dispersal and mobility, size, form, life history, and feeding groups) (15–120%). Responses, however, were stronger for terrestrial than aquatic biota, and, contrary to our expectation, taxonomic responses were stronger than those of traits. Nevertheless, trait analysis provided mechanistic insights into the drivers of community change following restoration. Trait analysis for terrestrial biota indicated restoration success was likely enhanced by lateral connectivity and reestablishment of dynamic processes in the floodplain. The weaker response of aquatic biota suggests recovery was hindered by the persistence of stressors in the aquatic environment, such as degraded water quality, dispersal constraints, and insufficient hydromorphological change. Therefore, river restoration requires combined local- and regional-scale approaches to maximize the response of both aquatic and terrestrial organisms. Due to the contrasting responses of aquatic and terrestrial biota, the planning and assessment of river restoration outcomes should consider effects on both components of riverine landscapes.
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| 31. |
- Pilotto, Francesca, et al.
(författare)
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Meta-analysis of multidecadal biodiversity trends in Europe
- 2020
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Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Local biodiversity trends over time are likely to be decoupled from global trends, as local processes may compensate or counteract global change. We analyze 161 long-term biological time series (15-91 years) collected across Europe, using a comprehensive dataset comprising ~6,200 marine, freshwater and terrestrial taxa. We test whether (i) local long-term biodiversity trends are consistent among biogeoregions, realms and taxonomic groups, and (ii) changes in biodiversity correlate with regional climate and local conditions. Our results reveal that local trends of abundance, richness and diversity differ among biogeoregions, realms and taxonomic groups, demonstrating that biodiversity changes at local scale are often complex and cannot be easily generalized. However, we find increases in richness and abundance with increasing temperature and naturalness as well as a clear spatial pattern in changes in community composition (i.e. temporal taxonomic turnover) in most biogeoregions of Northern and Eastern Europe. The global biodiversity decline might conceal complex local and group-specific trends. Here the authors report a quantitative synthesis of longterm biodiversity trends across Europe, showing how, despite overall increase in biodiversity metric and stability in abundance, trends differ between regions, ecosystem types, and taxa.
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| 32. |
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| 33. |
- Shevchenko, Elena V, et al.
(författare)
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Study of nucleation and growth in the organometallic synthesis of magnetic alloy nanocrystals : the role of nucleation rate in size control of CoPt3 nanocrystals
- 2003
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 125:30, s. 9090-9101
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Tidskriftsartikel (refereegranskat)abstract
- High quality CoPt(3) nanocrystals were synthesized via simultaneous reduction of platinum acetylacetonate and thermodecomposition of cobalt carbonyl in the presence of 1-adamantanecarboxylic acid and hexadecylamine as stabilizing agents. The high flexibility and reproducibility of the synthesis allows us to consider CoPt(3) nanocrystals as a model system for the hot organometallic synthesis of metal nanoparticles. Different experimental conditions (reaction temperature, concentration of stabilizing agents, ratio between cobalt and platinum precursors, etc.) have been investigated to reveal the processes governing the formation of the metal alloy nanocrystals. It was found that CoPt(3) nanocrystals nucleate and grow up to their final size at an early stage of the synthesis with no Ostwald ripening observed upon further heating. In this case, the nanocrystal size can be controlled only via proper balance between the rates for nucleation and for growth from the molecular precursors. Thus, the size of CoPt(3) nanocrystals can be precisely tuned from approximately 3 nm up to approximately 18 nm in a predictable and reproducible way. The mechanism of homogeneous nucleation, evolution of the nanocrystal ensemble in the absence of Ostwald ripening, nanocrystal faceting, and size-dependent magnetic properties are investigated and discussed on the example of CoPt(3) magnetic alloy nanocrystals. The developed approach was found to be applicable to other systems, e.g., FePt and CoPd(2) magnetic alloy nanocrystals.
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| 34. |
- Steele, Christopher D, et al.
(författare)
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Signatures of copy number alterations in human cancer
- 2022
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 606:7916, s. 984-991
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Tidskriftsartikel (refereegranskat)abstract
- Gains and losses of DNA are prevalent in cancer and emerge as a consequence of inter-related processes of replication stress, mitotic errors, spindle multipolarity and breakage-fusion-bridge cycles, among others, which may lead to chromosomal instability and aneuploidy1,2. These copy number alterations contribute to cancer initiation, progression and therapeutic resistance3-5. Here we present a conceptual framework to examine the patterns of copy number alterations in human cancer that is widely applicable to diverse data types, including whole-genome sequencing, whole-exome sequencing, reduced representation bisulfite sequencing, single-cell DNA sequencing and SNP6 microarray data. Deploying this framework to 9,873 cancers representing 33 human cancer types from The Cancer Genome Atlas6 revealed a set of 21 copy number signatures that explain the copy number patterns of 97% of samples. Seventeen copy number signatures were attributed to biological phenomena of whole-genome doubling, aneuploidy, loss of heterozygosity, homologous recombination deficiency, chromothripsis and haploidization. The aetiologies of four copy number signatures remain unexplained. Some cancer types harbour amplicon signatures associated with extrachromosomal DNA, disease-specific survival and proto-oncogene gains such as MDM2. In contrast to base-scale mutational signatures, no copy number signature was associated with many known exogenous cancer risk factors. Our results synthesize the global landscape of copy number alterations in human cancer by revealing a diversity of mutational processes that give rise to these alterations.
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| 35. |
- Vallenhag, Linda, et al.
(författare)
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A combined small- and wide-angle x-ray scattering detector for measurements on reactive systems
- 2011
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 1089-7623 .- 0034-6748. ; 82:8
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Tidskriftsartikel (refereegranskat)abstract
- A detector with high dynamic range designed for combined small-and wide-angle x-ray scattering experiments has been developed. It allows measurements on single events and reactive systems, such as particle formation in flames and evaporation of levitating drops. The detector consists of 26 channels covering a region from 0.5 degrees to 60 degrees and it provides continuous monitoring of the sampled signal without readout dead time. The time resolution for fast single events is about 40 mu s and for substances undergoing slower dynamics, the time resolution is set to 0.1 or 1 s with hours of continuous sampling. The detector has been used to measure soot particle formation in a flame, burning magnesium and evaporation of a toluene drop in a levitator. The results show that the detector can be used for many different applications with good outcomes and large potential. (C) 2011 American Institute of Physics. [doi:10.1063/1.3613958]
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