| 1. |
- Barbero-Palacios, Laura, et al.
(author)
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Herbivore diversity effects on Arctic tundra ecosystems : a systematic review
- 2024
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In: Environmental Evidence. - : BioMed Central (BMC). - 2047-2382. ; 13:1
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Research review (peer-reviewed)abstract
- Background: Northern ecosystems are strongly influenced by herbivores that differ in their impacts on the ecosystem. Yet the role of herbivore diversity in shaping the structure and functioning of tundra ecosystems has been overlooked. With climate and land-use changes causing rapid shifts in Arctic species assemblages, a better understanding of the consequences of herbivore diversity changes for tundra ecosystem functioning is urgently needed. This systematic review synthesizes available evidence on the effects of herbivore diversity on different processes, functions, and properties of tundra ecosystems.Methods: Following a published protocol, our systematic review combined primary field studies retrieved from bibliographic databases, search engines and specialist websites that compared tundra ecosystem responses to different levels of vertebrate and invertebrate herbivore diversity. We used the number of functional groups of herbivores (i.e., functional group richness) as a measure of the diversity of the herbivore assemblage. We screened titles, abstracts, and full texts of studies using pre-defined eligibility criteria. We critically appraised the validity of the studies, tested the influence of different moderators, and conducted sensitivity analyses. Quantitative synthesis (i.e., calculation of effect sizes) was performed for ecosystem responses reported by at least five articles and meta-regressions including the effects of potential modifiers for those reported by at least 10 articles.Review findings: The literature searches retrieved 5944 articles. After screening titles, abstracts, and full texts, 201 articles including 3713 studies (i.e., individual comparisons) were deemed relevant for the systematic review, with 2844 of these studies included in quantitative syntheses. The available evidence base on the effects of herbivore diversity on tundra ecosystems is concentrated around well-established research locations and focuses mainly on the impacts of vertebrate herbivores on vegetation. Overall, greater herbivore diversity led to increased abundance of feeding marks by herbivores and soil temperature, and to reduced total abundance of plants, graminoids, forbs, and litter, plant leaf size, plant height, and moss depth, but the effects of herbivore diversity were difficult to tease apart from those of excluding vertebrate herbivores. The effects of different functional groups of herbivores on graminoid and lichen abundance compensated each other, leading to no net effects when herbivore effects were combined. In turn, smaller herbivores and large-bodied herbivores only reduced plant height when occurring together but not when occurring separately. Greater herbivore diversity increased plant diversity in graminoid tundra but not in other habitat types.Conclusions: This systematic review underscores the importance of herbivore diversity in shaping the structure and function of Arctic ecosystems, with different functional groups of herbivores exerting additive or compensatory effects that can be modulated by environmental conditions. Still, many challenges remain to fully understand the complex impacts of herbivore diversity on tundra ecosystems. Future studies should explicitly address the role of herbivore diversity beyond presence-absence, targeting a broader range of ecosystem responses and explicitly including invertebrate herbivores. A better understanding of the role of herbivore diversity will enhance our ability to predict whether and where shifts in herbivore assemblages might mitigate or further amplify the impacts of environmental change on Arctic ecosystems.
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| 2. |
- Haghighi, Mona, et al.
(author)
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A Comparison of Rule-based Analysis with Regression Methods in Understanding the Risk Factors for Study Withdrawal in a Pediatric Study
- 2016
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 6
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Journal article (peer-reviewed)abstract
- Regression models are extensively used in many epidemiological studies to understand the linkage between specific outcomes of interest and their risk factors. However, regression models in general examine the average effects of the risk factors and ignore subgroups with different risk profiles. As a result, interventions are often geared towards the average member of the population, without consideration of the special health needs of different subgroups within the population. This paper demonstrates the value of using rule-based analysis methods that can identify subgroups with heterogeneous risk profiles in a population without imposing assumptions on the subgroups or method. The rules define the risk pattern of subsets of individuals by not only considering the interactions between the risk factors but also their ranges. We compared the rule-based analysis results with the results from a logistic regression model in The Environmental Determinants of Diabetes in the Young (TEDDY) study. Both methods detected a similar suite of risk factors, but the rule-based analysis was superior at detecting multiple interactions between the risk factors that characterize the subgroups. A further investigation of the particular characteristics of each subgroup may detect the special health needs of the subgroup and lead to tailored interventions.
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| 3. |
- Kotta, Jonne, et al.
(author)
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Cleaning up seas using blue growth initiatives: Mussel farming for eutrophication control in the Baltic Sea
- 2020
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In: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 709
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Journal article (peer-reviewed)abstract
- © 2019 The Authors Eutrophication is a serious threat to aquatic ecosystems globally with pronounced negative effects in the Baltic and other semi-enclosed estuaries and regional seas, where algal growth associated with excess nutrients causes widespread oxygen free “dead zones” and other threats to sustainability. Decades of policy initiatives to reduce external (land-based and atmospheric) nutrient loads have so far failed to control Baltic Sea eutrophication, which is compounded by significant internal release of legacy phosphorus (P) and biological nitrogen (N) fixation. Farming and harvesting of the native mussel species (Mytilus edulis/trossulus) is a promising internal measure for eutrophication control in the brackish Baltic Sea. Mussels from the more saline outer Baltic had higher N and P content than those from either the inner or central Baltic. Despite their relatively low nutrient content, harvesting farmed mussels from the central Baltic can be a cost-effective complement to land-based measures needed to reach eutrophication status targets and is an important contributor to circularity. Cost effectiveness of nutrient removal is more dependent on farm type than mussel nutrient content, suggesting the need for additional development of farm technology. Furthermore, current regulations are not sufficiently conducive to implementation of internal measures, and may constitute a bottleneck for reaching eutrophication status targets in the Baltic Sea and elsewhere.
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| 4. |
- Kotta, Jonne, et al.
(author)
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Integrating experimental and distribution data to predict future species patterns
- 2019
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In: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 9
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Journal article (peer-reviewed)abstract
- Predictive species distribution models are mostly based on statistical dependence between environmental and distributional data and therefore may fail to account for physiological limits and biological interactions that are fundamental when modelling species distributions under future climate conditions. Here, we developed a state-of-the-art method integrating biological theory with survey and experimental data in a way that allows us to explicitly model both physical tolerance limits of species and inherent natural variability in regional conditions and thereby improve the reliability of species distribution predictions under future climate conditions. By using a macroalga-herbivore association (Fucus vesiculosus - Idotea balthica) as a case study, we illustrated how salinity reduction and temperature increase under future climate conditions may significantly reduce the occurrence and biomass of these important coastal species. Moreover, we showed that the reduction of herbivore occurrence is linked to reduction of their host macroalgae. Spatial predictive modelling and experimental biology have been traditionally seen as separate fields but stronger interlinkages between these disciplines can improve species distribution projections under climate change. Experiments enable qualitative prior knowledge to be defined and identify cause-effect relationships, and thereby better foresee alterations in ecosystem structure and functioning under future climate conditions that are not necessarily seen in projections based on non-causal statistical relationships alone.
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| 5. |
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| 6. |
- Lundgren, Markus, et al.
(author)
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Analgesic antipyretic use among young children in the TEDDY study : No association with islet autoimmunity
- 2017
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In: BMC Pediatrics. - : Springer Science and Business Media LLC. - 1471-2431. ; 17:1
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Journal article (peer-reviewed)abstract
- Background: The use of analgesic antipyretics (ANAP) in children have long been a matter of controversy. Data on their practical use on an individual level has, however, been scarce. There are indications of possible effects on glucose homeostasis and immune function related to the use of ANAP. The aim of this study was to analyze patterns of analgesic antipyretic use across the clinical centers of The Environmental Determinants of Diabetes in the Young (TEDDY) prospective cohort study and test if ANAP use was a risk factor for islet autoimmunity. Methods: Data were collected for 8542 children in the first 2.5 years of life. Incidence was analyzed using logistic regression with country and first child status as independent variables. Holm's procedure was used to adjust for multiplicity of intercountry comparisons. Time to autoantibody seroconversion was analyzed using a Cox proportional hazards model with cumulative analgesic use as primary time dependent covariate of interest. For each categorization, a generalized estimating equation (GEE) approach was used. Results: Higher prevalence of ANAP use was found in the U.S. (95.7%) and Sweden (94.8%) compared to Finland (78.1%) and Germany (80.2%). First-born children were more commonly given acetaminophen (OR 1.26; 95% CI 1.07, 1.49; p = 0.007) but less commonly Non-Steroidal Anti-inflammatory Drugs (NSAID) (OR 0.86; 95% CI 0.78, 0.95; p = 0.002). Acetaminophen and NSAID use in the absence of fever and infection was more prevalent in the U.S. (40.4%; 26.3% of doses) compared to Sweden, Finland and Germany (p < 0.001). Acetaminophen or NSAID use before age 2.5 years did not predict development of islet autoimmunity by age 6 years (HR 1.02, 95% CI 0.99-1.09; p = 0.27). In a sub-analysis, acetaminophen use in children with fever weakly predicted development of islet autoimmunity by age 3 years (HR 1.05; 95% CI 1.01-1.09; p = 0.024). Conclusions: ANAP use in young children is not a risk factor for seroconversion by age 6 years. Use of ANAP is widespread in young children, and significantly higher in the U.S. compared to other study sites, where use is common also in absence of fever and infection.
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| 7. |
- Pajunen, A.M., et al.
(author)
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Compositional differentiation, vegetation-environment relationships and classification of willow-characterised vegetation in the western Eurasian Arctic
- 2010
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In: Journal of Vegetation Science. - : Wiley. - 1100-9233 .- 1654-1103. ; 21:1, s. 107-119
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Journal article (peer-reviewed)abstract
- Question: How does willow-characterised tundra vegetation of western Eurasia vary, and what are the main vegetation types? What are the ecological gradients and climatic regimes underlying vegetation differentiation?Location: The dataset was collected across a wide spectrum of tundra habitats at 12 sites in subarctic and arctic areas spanning from NW Fennoscandia to West Siberia.Methods: The dataset, including 758 vegetation sample plots (relevés), was analysed using a TWINSPAN classification and NMDS ordination that also included analyses of vegetation-environment correlations.Results: Based on the TWINSPAN classification, eight vegetation types characterised by willow (cover of upright willows >10%) were discerned: (1) Salix glauca-Carex aquatilis type, (2) Aulacomnium-Tomentypnum type, (3) Salix-Betula-Hylocomium type, (4) Salix lanata-Brachythecium mildeanum type, (5) Salix-Pachypleurum type, (6) S. lanata-Myosotis nemorosa type, (7) Salix-Trollius-Geranium type and (8) Salix-Comarum palustre-Filipendula ulmaria type. Willow-characterised vegetation types were compositionally differentiated from other tundra vegetation and were confined to relatively moist valley and sloping tundra sites, from mire to mineral soils. These vegetation types were encountered across a broad latitudinal zone in which July mean temperature ranged from 6 to 10°C.Conclusions: Willow-characterised tundra vegetation forms a broad category of ecologically and geographically differentiated vegetation types that are linked to dwarf shrub tundra, shrub tundra or mire. Because of complex ecological gradients underlying compositional differentiation, predicting the responses of willow-characterised tundra vegetation to a warming climate may be complicated.
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| 8. |
- Rauhala, Elina, et al.
(author)
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Change in brain amyloid load and cognition in patients with amnestic mild cognitive impairment : a 3-year follow-up study
- 2022
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In: EJNMMI Research. - : Springer. - 2191-219X. ; 12:1
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Journal article (peer-reviewed)abstract
- Background: Our aim was to investigate the discriminative value of 18F-Flutemetamol PET in longitudinal assessment of amyloid beta accumulation in amnestic mild cognitive impairment (aMCI) patients, in relation to longitudinal cognitive changes.Methods: We investigated the change in 18F-Flutemetamol uptake and cognitive impairment in aMCI patients over time up to 3 years which enabled us to investigate possible association between changes in brain amyloid load and cognition over time. Thirty-four patients with aMCI (mean age 73.4 years, SD 6.6) were examined with 18F-Flutemetamol PET scan, brain MRI and cognitive tests at baseline and after 3-year follow-up or earlier if the patient had converted to Alzheimer´s disease (AD). 18F-Flutemetamol data were analyzed both with automated region-of-interest analysis and voxel-based statistical parametric mapping.Results: 18F-flutemetamol uptake increased during the follow-up, and the increase was significantly higher in patients who were amyloid positive at baseline as compared to the amyloid-negative ones. At follow-up, there was a significant association between 18F-Flutemetamol uptake and MMSE, logical memory I (immediate recall), logical memory II (delayed recall) and verbal fluency. An association was seen between the increase in 18F-Flutemetamol uptake and decline in MMSE and logical memory I scores.Conclusions: In the early phase of aMCI, presence of amyloid pathology at baseline strongly predicted amyloid accumulation during follow-up, which was further paralleled by cognitive declines. Inversely, some of our patients remained amyloid negative also at the end of the study without significant change in 18F-Flutemetamol uptake or cognition. Future studies with longer follow-up are needed to distinguish whether the underlying pathophysiology of aMCI in such patients is other than AD.
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| 9. |
- Virtanen, Elina A., et al.
(author)
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Identifying areas prone to coastal hypoxia - the role of topography
- 2019
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In: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 16:16, s. 3183-3195
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Journal article (peer-reviewed)abstract
- Hypoxia is an increasing problem in marine ecosystems around the world. While major advances have been made in our understanding of the drivers of hypoxia, challenges remain in describing oxygen dynamics in coastal regions. The complexity of many coastal areas and lack of detailed in situ data have hindered the development of models describing oxygen dynamics at a sufficient spatial resolution for efficient management actions to take place. It is well known that the enclosed nature of seafloors and reduced water mixing facilitates hypoxia formation, but the degree to which topography contributes to hypoxia formation and small-scale variability of coastal hypoxia has not been previously quantified. We developed simple proxies of seafloor heterogeneity and modeled oxygen deficiency in complex coastal areas in the northern Baltic Sea. According to our models, topographical parameters alone explained similar to 80 % of hypoxia occurrences. The models also revealed that less than 25 % of the studied seascapes were prone to hypoxia during late summer (August-September). However, large variation existed in the spatial and temporal patterns of hypoxia, as certain areas were prone to occasional severe hypoxia (O-2 < 2 mg L-1), while others were more susceptible to recurrent moderate hypoxia (O-2 < 4.6 mg L-1). Areas identified as problematic in our study were characterized by low exposure to wave forcing, high topographic shelter from surrounding areas and isolation from the open sea, all contributing to longer water residence times in seabed depressions. Deviations from this topographical background are probably caused by strong currents or high nutrient loading, thus improving or worsening oxygen status, respectively. In some areas, connectivity with adjacent deeper basins may also influence coastal oxygen dynamics. Developed models could boost the performance of biogeochemical models, aid developing nutrient abatement measures and pinpoint areas where management actions are most urgently needed.
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| 10. |
- Virtanen, Jyrki K., et al.
(author)
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Vitamin D supplementation and prevention of cardiovascular disease and cancer in the Finnish Vitamin D Trial : a randomized controlled trial
- 2022
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In: American Journal of Clinical Nutrition. - : Oxford University Press. - 0002-9165 .- 1938-3207. ; 115:5, s. 1300-1310
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Journal article (peer-reviewed)abstract
- BACKGROUND: Vitamin D insufficiency is associated with risk of cardiovascular diseases (CVD) and cancer in observational studies, but evidence for benefits with vitamin D supplementation is limited.OBJECTIVES: To investigate the effects of vitamin D3 supplementation on CVD and cancer incidence.DESIGN: The study was a 5-year randomized placebo-controlled trial among 2495 male participants ≥ 60 years and post-menopausal female participants ≥ 65 years from a general Finnish population who were free of prior CVD or cancer. The study had three arms: placebo, 1600 IU/day or 3200 IU/day vitamin D3. Follow-up was by annual study questionnaires and national registry data. A representative sub-cohort of 551 participants had more detailed in-person investigations. The primary endpoints were incident major CVD and invasive cancer. Secondary endpoints included the individual components of the primary CVD endpoint (myocardial infarction, stroke, and CVD mortality), site-specific cancers and cancer death.RESULTS: During the follow-up, there were 41 (4.9%), 42 (5.0%) and 36 (4.3%) major CVD events in the placebo, 1600 IU/d (vs. placebo: hazard ratio (HR), 0.97;95% CI, 0.63,1.49; P = 0.89), and 3200 IU/d (HR, 0.84;95% CI, 0.54,1.31; P = 0.44) arms, respectively. Invasive cancer was diagnosed in 41 (4.9%), 48 (5.8%) and 40 (4.8%) participants in the placebo, 1600 IU/d (HR, 1.14;95% CI, 0.75,1.72; P = 0.55), and 3200 IU/d (HR, 0.95;95% CI, 0.61,1.47; P = 0.81) arms, respectively. There were no significant differences in the secondary endpoints or total mortality. In the sub-cohort, the mean (standard deviation) baseline serum 25-hydroxyvitamin D concentration was 75 (18) nmol/L. After 12 months, the concentrations were 73 (18) nmol/L, 100 (21) nmol/L and 120 (22) nmol/L in the placebo, 1600 IU/d and 3200 IU/d arms, respectively.CONCLUSIONS: Vitamin D3 supplementation did not lower the incidence of major CVD events or invasive cancer among older adults, possibly due to sufficient vitamin D status in most participants at baseline. Clinical Trial Registry number: ClinicalTrials.gov: NCT01463813, https://clinicaltrials.gov/ct2/show/NCT01463813.
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