| 1. |
- Ely, K. S., et al.
(författare)
-
A reporting format for leaf-level gas exchange data and metadata
- 2021
-
Ingår i: Ecological Informatics. - : Elsevier BV. - 1574-9541. ; 61
-
Tidskriftsartikel (refereegranskat)abstract
- Leaf-level gas exchange data support the mechanistic understanding of plant fluxes of carbon and water. These fluxes inform our understanding of ecosystem function, are an important constraint on parameterization of terrestrial biosphere models, are necessary to understand the response of plants to global environmental change, and are integral to efforts to improve crop production. Collection of these data using gas analyzers can be both technically challenging and time consuming, and individual studies generally focus on a small range of species, restricted time periods, or limited geographic regions. The high value of these data is exemplified by the many publications that reuse and synthesize gas exchange data, however the lack of metadata and data reporting conventions make full and efficient use of these data difficult. Here we propose a reporting format for leaf-level gas exchange data and metadata to provide guidance to data contributors on how to store data in repositories to maximize their discoverability, facilitate their efficient reuse, and add value to individual datasets. For data users, the reporting format will better allow data repositories to optimize data search and extraction, and more readily integrate similar data into harmonized synthesis products. The reporting format specifies data table variable naming and unit conventions, as well as metadata characterizing experimental conditions and protocols. For common data types that were the focus of this initial version of the reporting format, i.e., survey measurements, dark respiration, carbon dioxide and light response curves, and parameters derived from those measurements, we took a further step of defining required additional data and metadata that would maximize the potential reuse of those data types. To aid data contributors and the development of data ingest tools by data repositories we provided a translation table comparing the outputs of common gas exchange instruments. Extensive consultation with data collectors, data users, instrument manufacturers, and data scientists was undertaken in order to ensure that the reporting format met community needs. The reporting format presented here is intended to form a foundation for future development that will incorporate additional data types and variables as gas exchange systems and measurement approaches advance in the future. The reporting format is published in the U.S. Department of Energy?s ESS-DIVE data repository, with documentation and future development efforts being maintained in a version control system.
|
|
| 2. |
- Rixen, C., et al.
(författare)
-
Winters are changing: snow effects on Arctic and alpine tundra ecosystems
- 2022
-
Ingår i: Arctic Science. - : Canadian Science Publishing. - 2368-7460. ; 8:3, s. 572-608
-
Tidskriftsartikel (refereegranskat)abstract
- Snow is an important driver of ecosystem processes in cold biomes. Snow accumulation determines ground temperature, light conditions, and moisture availability during winter. It also affects the growing season's start and end, and plant access to moisture and nutrients. Here, we review the current knowledge of the snow cover's role for vegetation, plant-animal interactions, permafrost conditions, microbial processes, and biogeochemical cycling. We also compare studies of natural snow gradients with snow experimental manipulation studies to assess time scale difference of these approaches. The number of tundra snow studies has increased considerably in recent years, yet we still lack a comprehensive overview of how altered snow conditions will affect these ecosystems. Specifically, we found a mismatch in the timing of snowmelt when comparing studies of natural snow gradients with snow manipulations. We found that snowmelt timing achieved by snow addition and snow removal manipulations (average 7.9 days advance and 5.5 days delay, respectively) were substantially lower than the temporal variation over natural spatial gradients within a given year (mean range 56 days) or among years (mean range 32 days). Differences between snow study approaches need to be accounted for when projecting snow dynamics and their impact on ecosystems in future climates.
|
|
| 3. |
- Winkler, TW, et al.
(författare)
-
Differential and shared genetic effects on kidney function between diabetic and non-diabetic individuals
- 2022
-
Ingår i: Communications biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 5:1, s. 580-
-
Tidskriftsartikel (refereegranskat)abstract
- Reduced glomerular filtration rate (GFR) can progress to kidney failure. Risk factors include genetics and diabetes mellitus (DM), but little is known about their interaction. We conducted genome-wide association meta-analyses for estimated GFR based on serum creatinine (eGFR), separately for individuals with or without DM (nDM = 178,691, nnoDM = 1,296,113). Our genome-wide searches identified (i) seven eGFR loci with significant DM/noDM-difference, (ii) four additional novel loci with suggestive difference and (iii) 28 further novel loci (including CUBN) by allowing for potential difference. GWAS on eGFR among DM individuals identified 2 known and 27 potentially responsible loci for diabetic kidney disease. Gene prioritization highlighted 18 genes that may inform reno-protective drug development. We highlight the existence of DM-only and noDM-only effects, which can inform about the target group, if respective genes are advanced as drug targets. Largely shared effects suggest that most drug interventions to alter eGFR should be effective in DM and noDM.
|
|
| 4. |
- Lembrechts, Jonas J., et al.
(författare)
-
SoilTemp : A global database of near-surface temperature
- 2020
-
Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 26:11, s. 6616-6629
-
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.
|
|
| 5. |
- Jónsdóttir, I. S., et al.
(författare)
-
Intraspecific trait variability is a key feature underlying high Arctic plant community resistance to climate warming
- 2022
-
Ingår i: Ecological Monographs. - : Wiley. - 0012-9615 .- 1557-7015.
-
Tidskriftsartikel (refereegranskat)abstract
- In the high Arctic, plant community species composition generally responds slowly to climate warming, whereas less is known about the community functional trait responses and consequences for ecosystem functioning. Slow species turnover and large distribution ranges of many Arctic plant species suggest a significant role of intraspecific trait variability in functional responses to climate change. Here, we compare taxonomic and functional community compositional responses to a long-term (17years) warming experiment in Svalbard, replicated across three major high Arctic habitats shaped by topography and contrasting snow regimes. We observed taxonomic compositional changes in all plant communities over time. Still, responses to experimental warming were minor and most pronounced in the drier habitats with relatively early snowmelt timing and long growing seasons (Cassiope and Dryas heaths). The habitats were clearly separated in functional trait space, defined by twelve size- and leaf economics-related traits, primarily due to interspecific trait variation. Functional traits also responded to experimental warming, most prominently in the Dryas heath and mostly due to intraspecific trait variation. Leaf area and leaf mass increased, and leaf δ15N decreased in response to the warming treatment. Intraspecific trait variability ranged between 30% and 71% of the total trait variation, reflecting functional resilience of those communities, dominated by long-lived plants, due to either phenotypic plasticity or genotypic variation that most likely underlies the observed resistance of high Arctic vegetation to climate warming. We further explored the consequences of trait variability for ecosystem functioning by measuring peak season CO2 fluxes. Together, environmental, taxonomic, and functional trait variables explained a large proportion of the variation in net ecosystem exchange (NEE), which increased when intraspecific trait variation was accounted for. In contrast, even though ecosystem respiration and gross ecosystem production both increased in response to warming across habitats, they were mainly driven by the direct kinetic impacts of temperature on plant physiology and biochemical processes. Our study shows that long-term experimental warming has a modest but significant effect on plant community functional trait composition and suggests that intraspecific trait variability is a key feature underlying high Arctic ecosystem resistance to climate warming.
|
|
| 6. |
- Vandvik, Vigdis, et al.
(författare)
-
Plant traits and associated data from a warming experiment, a seabird colony, and along elevation in Svalbard
- 2023
-
Ingår i: Scientific Data. - 2052-4463. ; 10:1
-
Tidskriftsartikel (refereegranskat)abstract
- The Arctic is warming at a rate four times the global average, while also being exposed to other global environmental changes, resulting in widespread vegetation and ecosystem change. Integrating functional trait-based approaches with multi-level vegetation, ecosystem, and landscape data enables a holistic understanding of the drivers and consequences of these changes. In two High Arctic study systems near Longyearbyen, Svalbard, a 20-year ITEX warming experiment and elevational gradients with and without nutrient input from nesting seabirds, we collected data on vegetation composition and structure, plant functional traits, ecosystem fluxes, multispectral remote sensing, and microclimate. The dataset contains 1,962 plant records and 16,160 trait measurements from 34 vascular plant taxa, for 9 of which these are the first published trait data. By integrating these comprehensive data, we bridge knowledge gaps and expand trait data coverage, including on intraspecific trait variation. These data can offer insights into ecosystem functioning and provide baselines to assess climate and environmental change impacts. Such knowledge is crucial for effective conservation and management in these vulnerable regions.
|
|
| 7. |
- Geange, Sonya R., et al.
(författare)
-
Next-generation field courses : Integrating Open Science and online learning
- 2021
-
Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 11:8, s. 3577-3587
-
Tidskriftsartikel (refereegranskat)abstract
- As Open Science practices become more commonplace, there is a need for the next generation of scientists to be well versed in these aspects of scientific research. Yet, many training opportunities for early career researchers (ECRs) could better emphasize or integrate Open Science elements. Field courses provide opportunities for ECRs to apply theoretical knowledge, practice new methodological approaches, and gain an appreciation for the challenges of real-life research, and could provide an excellent platform for integrating training in Open Science practices. Our recent experience, as primarily ECRs engaged in a field course interrupted by COVID-19, led us to reflect on the potential to enhance learning outcomes in field courses by integrating Open Science practices and online learning components. Specifically, we highlight the opportunity for field courses to align teaching activities with the recent developments and trends in how we conduct research, including training in: publishing registered reports, collecting data using standardized methods, adopting high-quality data documentation, managing data through reproducible workflows, and sharing and publishing data through appropriate channels. We also discuss how field courses can use online tools to optimize time in the field, develop open access resources, and cultivate collaborations. By integrating these elements, we suggest that the next generation of field courses will offer excellent arenas for participants to adopt Open Science practices.
|
|
| 8. |
- Halbritter, Aud H., et al.
(författare)
-
Plant trait and vegetation data along a 1314 m elevation gradient with fire history in Puna grasslands, Perú
- 2024
-
Ingår i: SCIENTIFIC DATA. - 2052-4463. ; 11:1
-
Tidskriftsartikel (refereegranskat)abstract
- Alpine grassland vegetation supports globally important biodiversity and ecosystems that are increasingly threatened by climate warming and other environmental changes. Trait-based approaches can support understanding of vegetation responses to global change drivers and consequences for ecosystem functioning. In six sites along a 1314 m elevational gradient in Puna grasslands in the Peruvian Andes, we collected datasets on vascular plant composition, plant functional traits, biomass, ecosystem fluxes, and climate data over three years. The data were collected in the wet and dry season and from plots with different fire histories. We selected traits associated with plant resource use, growth, and life history strategies (leaf area, leaf dry/wet mass, leaf thickness, specific leaf area, leaf dry matter content, leaf C, N, P content, C and N isotopes). The trait dataset contains 3,665 plant records from 145 taxa, 54,036 trait measurements (increasing the trait data coverage of the regional flora by 420%) covering 14 traits and 121 plant taxa (ca. 40% of which have no previous publicly available trait data) across 33 families.
|
|
| 9. |
|
|
| 10. |
- Chacón-Labella, Julia, et al.
(författare)
-
From a crisis to an opportunity : Eight insights for doing science in the COVID-19 era and beyond
- 2021
-
Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 11:8, s. 3588-3596
-
Tidskriftsartikel (refereegranskat)abstract
- The COVID-19 crisis has forced researchers in Ecology to change the way we work almost overnight. Nonetheless, the pandemic has provided us with several novel components for a new way of conducting science. In this perspective piece, we summarize eight central insights that are helping us, as early career researchers, navigate the uncertainties, fears, and challenges of advancing science during the COVID-19 pandemic. We highlight how innovative, collaborative, and often Open Science-driven developments that have arisen from this crisis can form a blueprint for a community reinvention in academia. Our insights include personal approaches to managing our new reality, maintaining capacity to focus and resilience in our projects, and a variety of tools that facilitate remote collaboration. We also highlight how, at a community level, we can take advantage of online communication platforms for gaining accessibility to conferences and meetings, and for maintaining research networks and community engagement while promoting a more diverse and inclusive community. Overall, we are confident that these practices can support a more inclusive and kinder scientific culture for the longer term.
|
|
| 11. |
- Halbritter, Aud H., et al.
(författare)
-
Trait differentiation and adaptation of plants along elevation gradients
- 2018
-
Ingår i: Journal of Evolutionary Biology. - : Wiley. - 1010-061X .- 1420-9101. ; 31:6, s. 784-800
-
Forskningsöversikt (refereegranskat)abstract
- Studies of genetic adaptation in plant populations along elevation gradients in mountains have a long history, but there has until now been neither a synthesis of how frequently plant populations exhibit adaptation to elevation nor an evaluation of how consistent underlying trait differences across species are. We reviewed studies of adaptation along elevation gradients (i) from a meta-analysis of phenotypic differentiation of three traits (height, biomass and phenology) from plants growing in 70 common garden experiments; (ii) by testing elevation adaptation using three fitness proxies (survival, reproductive output and biomass) from 14 reciprocal transplant experiments; (iii) by qualitatively assessing information at the molecular level, from 10 genomewide surveys and candidate gene approaches. We found that plants originating from high elevations were generally shorter and produced less biomass, but phenology did not vary consistently. We found significant evidence for elevation adaptation in terms of survival and biomass, but not for reproductive output. Variation in phenotypic and fitness responses to elevation across species was not related to life history traits or to environmental conditions. Molecular studies, which have focussed mainly on loci related to plant physiology and phenology, also provide evidence for adaptation along elevation gradients. Together, these studies indicate that genetically based trait differentiation and adaptation to elevation are widespread in plants. We conclude that a better understanding of the mechanisms underlying adaptation, not only to elevation but also to environmental change, will require more studies combining the ecological and molecular approaches.
|
|
| 12. |
|
|
| 13. |
- Hillmer, H., et al.
(författare)
-
Wide continuously tunable 1.55 μm vertical air-cavity wavelength selective elements for filters and VCSELs using micromachined actuation
- 2005
-
Ingår i: Opto-Ireland 2005. - : SPIE - International Society for Optical Engineering. - 0819458104 ; , s. 14-28
-
Konferensbidrag (refereegranskat)abstract
- Tailored scaling allows the effectiveness of physical effects and mechanical stability to be enhanced. This is shown for micromachined 1.55μm vertical-resonator-based filters and VCSELs, capable of wide, continuous, and kink-free tuning by a single control parameter. Tuning is achieved by mechanically actuating one or several membranes in a vertical air-gap resonator including two highly reflective DBR mirrors. Electrostatically actuatable single-chip filters including InP/air-gap DBR's (3.5 periods) reveal a continuous tuning up to 14% of the absolute wavelength. Varying a reverse voltage (U=0 .. -3.2V) between the membranes (almost flat in the unactuated condition) a tuning range up to 142nm was obtained. Varying a reverse voltage (U=0 .. -28V) between the membranes (strained and curved in the unactuated condition) a tuning range up to 221nm was obtained. Optically pumped and continuously tunable 1.55μm VCSELs show 26nm spectral tuning range, 400μW maximum output power, and 57dBm SMSR. This two-chip VCSEL has a movable top mirror membrane, which is precisely designed to obtain a specific air-gap length and a tailored radius of curvature in order to efficiently support the fundamental optical mode of the plane-concave resonator. The curved top mirror DBR membrane consists of periodically alternating differently stressed silicon nitride and silicon dioxide multilayers. The lower InP-based part consists of the InP/GaInAsP bottom DBR and the GaInAsP active region.
|
|
| 14. |
|
|
| 15. |
- Lewin, Erik, et al.
(författare)
-
On the origin of a third spectral component of C1s XPS-spectra for nc-TiC/a-C nanocomposite thin films
- 2008
-
Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 202:15, s. 3563-3570
-
Tidskriftsartikel (refereegranskat)abstract
- X-ray photoelectron spectroscopy (XPS) spectra of sputter-etched nc-TiC/a-C nanocomposite thin films published in literature show an extra feature of unknown origin in the C1s region. This feature is situated between the contributions of carbide and the carbon matrix. We have used high kinetic energy XPS (HIKE-XPS) on magnetron-sputtered nc-TiC/a-C thin films to show that this feature represents a third chemical environment in the nanocomposites, besides the carbide and the amorphous carbon. Our results show that component is present in as-deposited samples, and that the intensity is strongly enhanced by Ar+-ion etching. This third chemical environment may be due to interface or disorder effects. The implications of these observations on the XPS analysis of nanocomposites are discussed in the light of overlap problems for ternary carbon based systems.
|
|
| 16. |
- Schellong, S. M., et al.
(författare)
-
Ultrasound screening for asymptomatic deep vein thrombosis after major orthopaedic surgery: the VENUS study
- 2007
-
Ingår i: J Thromb Haemost. - 1538-7933.
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Venography is currently used to assess the incidence of deep vein thrombosis (DVT) in dose-finding and confirmatory trials of new antithrombotic agents. Centrally adjudicated, complete compression ultrasound (CCUS) could be a non-invasive alternative to venography. Objectives: A substudy of two, similarly designed, phase IIb trials of a novel, oral anticoagulant for the prevention of venous thromboembolism after elective hip or knee arthroplasty was undertaken to validate CCUS against venography. Patients/Methods: Patients received study drugs until mandatory, bilateral venography was performed 7 +/- 2 days after surgery. CCUS was performed within 24 hours after venography by sonographers blinded to the venography result. Sonographers were trained and certified for the standardized examination and documentation procedure. Venograms and sonograms were adjudicated centrally at different sites by two independent readers; discrepancies between readers were resolved by consensus. Results: A total of 1104 matching pairs of evaluable venograms and sonograms were obtained from the participants of the two trials (n = 1435): 19% of venograms and 20% of sonograms were not evaluable. The observed frequency of any DVT was 18.9% with venography and 11.5% with CCUS. Sensitivity of CCUS compared with venography was 31.1% for any DVT (95% confidence interval 23.4, 38.9), 21.0% (2.7, 39.4) for proximal DVT, and 30.8% (23.1, 38.6) for distal DVT. The figures for specificity were 93.0% (91.0, 95.1), 98.7% (98.0, 99.5), and 93.3% (91.5, 95.3), respectively. Conclusions: Based on these results, centrally adjudicated CCUS will be unable to replace venography for DVT screening early after major orthopaedic surgery in studies evaluating anticoagulant drugs.
|
|
| 17. |
- Tarraf, A., et al.
(författare)
-
Continuously tunable 1.55-mu m VCSEL implemented by precisely curved dielectric top DBR involving tailored stress
- 2004
-
Ingår i: IEEE Photonics Technology Letters. - 1041-1135 .- 1941-0174. ; 16:3, s. 720-722
-
Tidskriftsartikel (refereegranskat)abstract
- We present an optically pumped and continuously tunable 1.55-mum vertical-cavity surface-emitting laser (VCSEL). The device shows. 26-mn spectral tuning range, 400-muW maximum output power, and 57-dBm side-mode suppression ratio. The VCSEL is implemented using a two-chip concept. The movable top mirror membrane is precisely designed to obtain a tailored air-gap length (L' = 16 mum) and a radius of curvature (ROC = 4.5 mm) in order to efficiently support the fundamental optical mode of the plane-concave resonator. It consists of a distributed Bragg reflector (DBR) with periodic, differently stressed silicon nitride and silicon dioxide multilayers implemented by plasma-enhanced chemical vapor deposition. The lower InP-based part, comprising the InP-InGaAsP bottom DBR and the active region, is grown monolithicaily using metal-organic vapor phase epitaxy.
|
|
