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1.
  • Poyatos, R., et al. (författare)
  • Global transpiration data from sap flow measurements: the SAPFLUXNET database
  • 2021
  • Ingår i: Earth System Science Data. - : Copernicus GmbH. - 1866-3508 .- 1866-3516. ; 13:6, s. 2607-2649
  • Tidskriftsartikel (refereegranskat)abstract
    • Plant transpiration links physiological responses of vegetation to water supply and demand with hydrological, energy, and carbon budgets at the land-atmosphere interface. However, despite being the main land evaporative flux at the global scale, transpiration and its response to environmental drivers are currently not well constrained by observations. Here we introduce the first global compilation of whole-plant transpiration data from sap flow measurements (SAPFLUXNET, https://sapfluxnet.creaf.cat/, last access: 8 June 2021). We harmonized and quality-controlled individual datasets supplied by contributors worldwide in a semi-automatic data workflow implemented in the R programming language. Datasets include sub-daily time series of sap flow and hydrometeorological drivers for one or more growing seasons, as well as metadata on the stand characteristics, plant attributes, and technical details of the measurements. SAPFLUXNET contains 202 globally distributed datasets with sap flow time series for 2714 plants, mostly trees, of 174 species. SAPFLUXNET has a broad bioclimatic coverage, with woodland/shrubland and temperate forest biomes especially well represented (80 % of the datasets). The measurements cover a wide variety of stand structural characteristics and plant sizes. The datasets encompass the period between 1995 and 2018, with 50 % of the datasets being at least 3 years long. Accompanying radiation and vapour pressure deficit data are available for most of the datasets, while on-site soil water content is available for 56 % of the datasets. Many datasets contain data for species that make up 90 % or more of the total stand basal area, allowing the estimation of stand transpiration in diverse ecological settings. SAPFLUXNET adds to existing plant trait datasets, ecosystem flux networks, and remote sensing products to help increase our understanding of plant water use, plant responses to drought, and ecohydrological processes. SAPFLUXNET version 0.1.5 is freely available from the Zenodo repository (https://doi.org/10.5281/zenodo.3971689; Poyatos et al., 2020a). The "sapfluxnetr" R package - designed to access, visualize, and process SAPFLUXNET data - is available from CRAN.
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2.
  • 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.
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  • Birney, Ewan, et al. (författare)
  • Identification and analysis of functional elements in 1% of the human genome by the ENCODE pilot project
  • 2007
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 447:7146, s. 799-816
  • Tidskriftsartikel (refereegranskat)abstract
    • We report the generation and analysis of functional data from multiple, diverse experiments performed on a targeted 1% of the human genome as part of the pilot phase of the ENCODE Project. These data have been further integrated and augmented by a number of evolutionary and computational analyses. Together, our results advance the collective knowledge about human genome function in several major areas. First, our studies provide convincing evidence that the genome is pervasively transcribed, such that the majority of its bases can be found in primary transcripts, including non-protein-coding transcripts, and those that extensively overlap one another. Second, systematic examination of transcriptional regulation has yielded new understanding about transcription start sites, including their relationship to specific regulatory sequences and features of chromatin accessibility and histone modification. Third, a more sophisticated view of chromatin structure has emerged, including its inter-relationship with DNA replication and transcriptional regulation. Finally, integration of these new sources of information, in particular with respect to mammalian evolution based on inter- and intra-species sequence comparisons, has yielded new mechanistic and evolutionary insights concerning the functional landscape of the human genome. Together, these studies are defining a path for pursuit of a more comprehensive characterization of human genome function.
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6.
  • Brooks, P, et al. (författare)
  • A predictive framework for coupling Hydrology, Biogeochemistry, and Ecology
  • 2008
  • Ingår i: Vol. 10, EGU2008-A-09502, 2008.
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • The coupling of hydrological, biogeochemical, and ecological processes at catchment to landscape scale results in observable patterns in ecosystem structure, the amount and chemistry of stream discharge, and landsurface-atmosphere exchanges of energy and biogeochemicals. All of these patterns result from the close coupling of water, energy, carbon, and nutrient cycling, yet rarely are both the vertical (landsurfaceatmosphere) and lateral (hydrological residence time and streamflow) exchanges associated with a particular ecosystem structure studied in concert. Our research attempts to bridge this gap by focusing on how ecosystem structure, specifically vegetation, mediates four-dimensional (X,Y,Z, and time) fluxes of water, carbon, and nutrients in semi-arid environments of the southwestern United States. Our generalized approach involves an iterative combination of measurement, modeling, and experimentation where process-level inferences drawn from one research activity are used to develop testable hypothesis for related efforts. Preliminary results have linked spatial variability in hydrologic residence time to seasonal variability in nutrient limitation; spatial and interannual variability in water source with carbon uptake and isotopic signature; vegetation controls on both snow water input and soil moisture; and the importance of alluvial aquifers in stream and river biogeochemistry.
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8.
  • Hock, R, et al. (författare)
  • High Mountain Areas
  • 2019
  • Ingår i: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate. - : IPCC - Intergovernmental Panel on Climate Change. ; , s. 131-202
  • Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
    • The cryosphere (including, snow, glaciers, permafrost, lake and river ice) is an integral element of high- mountain regions, which are home to roughly 10% of the global population. Widespread cryosphere changes affect physical, biological and human systems in the mountains and surrounding lowlands, with impacts evident even in the ocean. Building on the IPCC’s Fifth Assessment Report (AR5), this chapter assesses new evidence on observed recent and projected changes in the mountain cryosphere as well as associated impacts, risks and adaptation measures related to natural and human systems. Impacts in response to climate changes independently of changes in the cryosphere are not assessed in this chapter. Polar mountains are included in Chapter 3, except those in Alaska and adjacent Yukon, Iceland, and Scandinavia, which are included in this chapter.
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9.
  • Lee, Benjamin H., et al. (författare)
  • FLT3 mutations confer enhanced proliferation and survival properties to multipotent progenitors in a murine model of chronic myelomonocytic leukemia
  • 2007
  • Ingår i: Cancer Cell. - : Elsevier BV. - 1878-3686 .- 1535-6108. ; 12:4, s. 367-380
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite their known transforming properties, the effects of leukemogenic FLT3-ITD mutations on hematopoietic stem and multipotent progenitor cells and on hematopoietic differentiation are not well understood. We report a mouse model harboring an ITD in the murine Flt3 locus that develops myeloproliferative disease resembling CMML and further identified FLT3-ITD mutations in a subset of human CMML. These findings correlated with an increase in number, cell cycling, and survival of multipotent stem and progenitor cells in an ITD dose-dependent manner in animals that exhibited alterations within their myeloid progenitor compartments and a block in normal B cell development. This model provides insights into the consequences of constitutive signaling by an oncogenic tyrosine kinase on hematopoietic progenitor quiescence, function, and cell fate.
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  • McDowell, K., et al. (författare)
  • Incremental prognostic value of biomarkers in PARADIGM-HF
  • 2023
  • Ingår i: European Journal of Heart Failure. - 1388-9842. ; 25:8, s. 1406-1414
  • Tidskriftsartikel (refereegranskat)abstract
    • Aims It is uncertain how much candidate biomarkers improve risk prediction when added to comprehensive models including routinely collected clinical and laboratory variables in heart failure. Methods and results Aldosterone, cystatin C, high-sensitivity troponin T (hs-TnT), galectin-3, growth differentiation factor-15 (GDF-15), kidney injury molecule-1, matrix metalloproteinase-2 and -9, soluble suppression of tumourigenicity-2, tissue inhibitor of metalloproteinase-1 (TIMP-1) and urinary albumin to creatinine ratio were measured in 1559 of PARADIGM-HF participants. We tested whether these biomarkers, individually or collectively, improved the performance of the PREDICT-HF prognostic model, which includes clinical, routine laboratory, and natriuretic peptide data, for the primary endpoint and cardiovascular and all-cause mortality. The mean age of participants was 67.3 +/- 9.9 years, 1254 (80.4%) were men and 1103 (71%) were in New York Heart Association class II. During a mean follow-up of 30.7 months, 300 patients experienced the primary outcome and 197 died. Added individually, only four biomarkers were independently associated with all outcomes: hs-TnT, GDF-15, cystatin C and TIMP-1. When all biomarkers were added simultaneously to the PREDICT-HF models, only hs-TnT remained an independent predictor of all three endpoints. GDF-15 also remained predictive of the primary endpoint; TIMP-1 was the only other predictor of both cardiovascular and all-cause mortality. Individually or in combination, these biomarkers did not lead to significant improvements in discrimination or reclassification. Conclusions None of the biomarkers studied individually or collectively led to a meaningful improvement in the prediction of outcomes over what is provided by clinical, routine laboratory, and natriuretic peptide variables.
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11.
  • Soranno, Patricia A., et al. (författare)
  • LAGOS-NE : A multi-scaled geospatial and temporal database of lake ecological context and water quality for thousands of U.S. lakes
  • 2017
  • Ingår i: GigaScience. - : Oxford University Press (OUP). - 2047-217X. ; 6:12, s. 1-22
  • Tidskriftsartikel (refereegranskat)abstract
    • Understanding the factors that affect water quality and the ecological services provided by freshwater ecosystems is an urgent global environmental issue. Predicting how water quality will respond to global changes not only requires water quality data, but also information about the ecological context of individual water bodies across broad spatial extents. Because lake water quality is usually sampled in limited geographic regions, often for limited time periods, assessing the environmental controls of water quality requires compilation of many data sets across broad regions and across time into an integrated database. LAGOS-NE accomplishes this goal for lakes in the northeastern-most 17 US states. LAGOS-NE contains data for 51101 lakes and reservoirs larger than 4 ha in 17 lake-rich US states. The database includes 3 datamodules for: lake location and physical characteristics for all lakes; ecological context (i.e., the land use, geologic, climatic, and hydrologic setting of lakes) for all lakes; and in situmeasurements of lake water quality for a subset of the lakes fromthe past 3 decades for approximately 2600–12 000 lakes depending on the variable. The database contains approximately 150000 measures of total phosphorus, 200 000 measures of chlorophyll, and 900 000 measures of Secchi depth. The water quality data were compiled from87 lake water quality data sets fromfederal, state, tribal, and non-profit agencies, university researchers, and citizen scientists. This database is one of the largest andmost comprehensive databases of its type because it includes both in situmeasurements and ecological context data. Because ecological context can be used to study a variety of other questions about lakes, streams, and wetlands, this database can also be used as the foundation for other studies of freshwaters at broad spatial and ecological scales
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12.
  • Vila-Castelar, C., et al. (författare)
  • Sex differences in blood biomarkers and cognitive performance in individuals with autosomal dominant Alzheimer's disease
  • 2023
  • Ingår i: Alzheimers & Dementia. - 1552-5260. ; 19:9, s. 4127-4138
  • Tidskriftsartikel (refereegranskat)abstract
    • INTRODUCTIONPlasma tau phosphorylated at threonine 217 (P-tau217) and neurofilament light (NfL) have emerged as markers of Alzheimer's disease (AD) pathology. Few studies have examined the role of sex in plasma biomarkers in sporadic AD, yielding mixed findings, and none in autosomal dominant AD. METHODSWe examined the effects of sex and age on plasma P-tau217 and NfL, and their association with cognitive performance in a cross-sectional study of 621 Presenilin-1 E280A mutation carriers (PSEN1) and non-carriers. RESULTSAs plasma P-tau217 levels increase, cognitively unimpaired female carriers showed better cognitive performance than cognitively unimpaired male carriers. Yet, as disease progresses, female carriers had a greater plasma NfL increase than male carriers. There were no sex differences in the association between age and plasma biomarkers among non-carriers. DISCUSSIONOur findings suggest that, among PSEN1 mutation carriers, females had a greater rate of neurodegeneration than males, yet it did not predict cognitive performance. HIGHLIGHTSWe examined sex differences in plasma P-tau217 and NfL in Presenilin-1 E280A (PSEN1) mutation carriers and non-carriers.Female carriers had a greater plasma NfL increase, but not P-tau217, than male carriers.As plasma P-tau217 levels increase, cognitively unimpaired female carriers showed better cognitive performance than cognitively unimpaired male carriers.The interaction effect of sex by plasma NfL levels did not predict cognition among carriers.
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  • Cole, J.J., et al. (författare)
  • Plumbing the global carbon cycle : Integrating inland waters into the terrestrial carbon budget
  • 2007
  • Ingår i: Ecosystems (New York. Print). - : Springer Science and Business Media LLC. - 1432-9840 .- 1435-0629. ; 10:1, s. 172-185
  • Forskningsöversikt (refereegranskat)abstract
    • Because freshwater covers such a small fraction of the Earth’s surface area, inland freshwater ecosystems (particularly lakes, rivers, and reservoirs) have rarely been considered as potentially important quantitative components of the carbon cycle at either global or regional scales. By taking published estimates of gas exchange, sediment accumulation, and carbon transport for a variety of aquatic systems, we have constructed a budget for the role of inland water ecosystems in the global carbon cycle. Our analysis conservatively estimates that inland waters annually receive, from a combination of background and anthropogenically altered sources, on the order of 1.9 Pg C y−1 from the terrestrial landscape, of which about 0.2 is buried in aquatic sediments, at least 0.8 (possibly much more) is returned to the atmosphere as gas exchange while the remaining 0.9 Pg y−1 is delivered to the oceans, roughly equally as inorganic and organic carbon. Thus, roughly twice as much C enters inland aquatic systems from land as is exported from land to the sea. Over prolonged time net carbon fluxes in aquatic systems tend to be greater per unit area than in much of the surrounding land. Although their area is small, these freshwater aquatic systems can affect regional C balances. Further, the inclusion of inland, freshwater ecosystems provides useful insight about the storage, oxidation and transport of terrestrial C, and may warrant a revision of how the modern net C sink on land is described.
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16.
  • Downing, J. A., et al. (författare)
  • Global abundance and size distribution of streams and rivers
  • 2012
  • Ingår i: Inland Waters. - 2044-2041 .- 2044-205X. ; 2:4, s. 229-236
  • Tidskriftsartikel (refereegranskat)abstract
    • To better integrate lotic ecosystems into global cycles and budgets, we provide approximations of the size-distribution and areal extent of streams and rivers. One approach we used was to employ stream network theory combined with data on stream width. We also used detailed stream networks on 2 continents to estimate the fraction of continental area occupied by streams worldwide and corrected remote sensing stream inventories for unresolved small streams. Our estimates of global fluvial area are 485 000 to 662 000 km2 and are +30–300% of published appraisals. Moderately sized rivers (orders 5–9) seem to comprise the greatest global area, with less area covered by low and high order streams, while global stream length, and therefore the riparian interface, is dominated by 1st order streams. Rivers and streams are likely to cover 0.30–0.56% of the land surface and make contributions to global processes and greenhouse gas emissions that may be +20–200% greater than those implied by previous estimates.
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17.
  • Downing, J. A., et al. (författare)
  • The global abundance and size distribution of lakes, ponds, and impoundments
  • 2006
  • Ingår i: Limnology and Oceanography. - 0024-3590 .- 1939-5590. ; 51:5, s. 2388-2397
  • Tidskriftsartikel (refereegranskat)abstract
    • One of the major impediments to the integration of lentic ecosystems into global environmental analyses has been fragmentary data on the extent and size distribution of lakes, ponds, and impoundments. We use new data sources, enhanced spatial resolution, and new analytical approaches to provide new estimates of the global abundance of surface-water bodies. A global model based on the Pareto distribution shows that the global extent of natural lakes is twice as large as previously known (304 million lakes; 4.2 million km(2) in area) and is dominated in area by millions of water bodies smaller than 1 km(2). Similar analyses of impoundments based on inventories of large, engineered dams show that impounded waters cover approximately 0.26 million km(2). However, construction of low-tech farm impoundments is estimated to be between 0.1% and 6% of farm area worldwide, dependent upon precipitation, and represents > 77,000 km(2) globally, at present. Overall, about 4.6 million km(2) of the earth's continental "land" surface (> 3%) is covered by water. These analyses underscore the importance of explicitly considering lakes, ponds, and impoundments, especially small ones, in global analyses of rates and processes.
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  • Lacy, Thomas E., et al. (författare)
  • On representation of damage evolution in continuum damage mechanics
  • 1997
  • Ingår i: International journal of damage mechanics. - : SAGE Publications. - 1056-7895 .- 1530-7921. ; 6:1, s. 62-95
  • Tidskriftsartikel (refereegranskat)abstract
    • The effect of damage patterning on elastic moduli and damage evolution in ideal brittle cracked solids is examined. Key limitations associated with typical continuum damage mechanics approaches are addressed. Critical shortcomings arising from the use of spatially-averaged damage descriptors in the evaluation of effective moduli and thermodynamic forces are investigated using numerical simulations of evolving two-dimensional crack systems. Fundamental elements of a higher-order continuum description of damage based on distribution functions are discussed, which directly include damage interaction effects.
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20.
  • Landhausser, S. M., et al. (författare)
  • Standardized protocols and procedures can precisely and accurately quantify non-structural carbohydrates
  • 2018
  • Ingår i: Tree Physiology. - : Oxford University Press (OUP). - 0829-318X .- 1758-4469. ; 38:12, s. 1764-1778
  • Tidskriftsartikel (refereegranskat)abstract
    • Non-structural carbohydrates (NSCs), the stored products of photosynthesis, building blocks for growth and fuel for respiration, are central to plant metabolism, but their measurement is challenging. Differences in methods and procedures among laboratories can cause results to vary widely, limiting our ability to integrate and generalize patterns in plant carbon balance among studies. A recent assessment found that NSC concentrations measured for a common set of samples can vary by an order of magnitude, but sources for this variability were unclear. We measured a common set of nine plant material types, and two synthetic samples with known NSC concentrations, using a common protocol for sugar extraction and starch digestion, and three different sugar quantification methods (ion chromatography, enzyme, acid) in six laboratories. We also tested how sample handling, extraction solvent and centralizing parts of the procedure in one laboratory affected results. Non-structural carbohydrate concentrations measured for synthetic samples were within about 11.5% of known values for all three methods. However, differences among quantification methods were the largest source of variation in NSC measurements for natural plant samples because the three methods quantify different NSCs. The enzyme method quantified only glucose, fructose and sucrose, with ion chromatography we additionally quantified galactose, while the acid method quantified a large range of mono- and oligosaccharides. For some natural samples, sugars quantified with the acid method were two to five times higher than with other methods, demonstrating that trees allocate carbon to a range of sugar molecules. Sample handling had little effect on measurements, while ethanol sugar extraction improved accuracy over water extraction. Our results demonstrate that reasonable accuracy of NSC measurements can be achieved when different methods are used, as long as protocols are robust and standardized. Thus, we provide detailed protocols for the extraction, digestion and quantification of NSCs in plant samples, which should improve the comparability of NSC measurements among laboratories.
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21.
  • Lensen, S., et al. (författare)
  • A Randomized Trial of Endometrial Scratching before In Vitro Fertilization
  • 2019
  • Ingår i: New England Journal of Medicine. - 0028-4793. ; 380:4, s. 325-334
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND Endometrial scratching (with the use of a pipelle biopsy) is a technique proposed to facilitate embryo implantation and increase the probability of pregnancy in women undergoing in vitro fertilization (IVF). We conducted a pragmatic, multicenter, open-label, randomized, controlled trial. Eligible women were undergoing IVF (fresh-embryo or frozen-embryo transfer), with no recent exposure to disruptive intrauterine instrumentation (e.g., hysteroscopy). Participants were randomly assigned in a 1: 1 ratio to either endometrial scratching (by pipelle biopsy between day 3 of the cycle preceding the embryo-transfer cycle and day 3 of the embryo-transfer cycle) or no intervention. The primary outcome was live birth. A total of 1364 women underwent randomization. The frequency of live birth was 180 of 690 women (26.1%) in the endometrial-scratch group and 176 of 674 women (26.1%) in the control group (adjusted odds ratio, 1.00; 95% confidence interval, 0.78 to 1.27). There were no significant between-group differences in the rates of ongoing pregnancy, clinical pregnancy, multiple pregnancy, ectopic pregnancy, or miscarriage. The median score for pain from endometrial scratching (on a scale of 0 to 10, with higher scores indicating worse pain) was 3.5 (interquartile range, 1.9 to 6.0). Endometrial scratching did not result in a higher rate of live birth than no intervention among women undergoing IVF.
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22.
  • Løkkegaard, Anja, et al. (författare)
  • Greenland and Canadian Arctic ice temperature profiles database
  • 2023
  • Ingår i: The Cryosphere. - : Copernicus Publications. - 1994-0416 .- 1994-0424. ; 17:9, s. 3829-3845
  • Tidskriftsartikel (refereegranskat)abstract
    • Here, we present a compilation of 95 ice temperature profiles from 85 boreholes from the Greenland ice sheet and peripheral ice caps, as well as local ice caps in the Canadian Arctic. Profiles from only 31 boreholes (36 %) were previously available in open-access data repositories. The remaining 54 borehole profiles (64 %) are being made digitally available here for the first time. These newly available profiles, which are associated with pre-2010 boreholes, have been submitted by community members or digitized from published graphics and/or data tables. All 95 profiles are now made available in both absolute (meters) and normalized (0 to 1 ice thickness) depth scales and are accompanied by extensive metadata. These metadata include a transparent description of data provenance. The ice temperature profiles span 70 years, with the earliest profile being from 1950 at Camp VI, West Greenland. To highlight the value of this database in evaluating ice flow simulations, we compare the ice temperature profiles from the Greenland ice sheet with an ice flow simulation by the Parallel Ice Sheet Model (PISM). We find a cold bias in modeled near-surface ice temperatures within the ablation area, a warm bias in modeled basal ice temperatures at inland cold-bedded sites, and an apparent underestimation of deformational heating in high-strain settings. These biases provide process level insight on simulated ice temperatures.
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23.
  • McDowell, Kirsty, et al. (författare)
  • Prognostic Models for Mortality and Morbidity in Heart Failure with Preserved Ejection Fraction
  • 2024
  • Ingår i: JAMA Cardiology. - 2380-6583. ; 9:5, s. 457-465
  • Tidskriftsartikel (refereegranskat)abstract
    • Importance: Accurate risk prediction of morbidity and mortality in patients with heart failure with preserved ejection fraction (HFpEF) may help clinicians risk stratify and inform care decisions. Objective: To develop and validate a novel prediction model for clinical outcomes in patients with HFpEF using routinely collected variables and to compare it with a biomarker-driven approach. Design, Setting, and Participants: Data were used from the Dapagliflozin Evaluation to Improve the Lives of Patients With Preserved Ejection Fraction Heart Failure (DELIVER) trial to derive the prediction model, and data from the Angiotensin Receptor Neprilysin Inhibition in Heart Failure With Preserved Ejection Fraction (PARAGON-HF) and the Irbesartan in Heart Failure With Preserved Ejection Fraction Study (I-PRESERVE) trials were used to validate it. The outcomes were the composite of HF hospitalization (HFH) or cardiovascular death, cardiovascular death, and all-cause death. A total of 30 baseline candidate variables were selected in a stepwise fashion using multivariable analyses to create the models. Data were analyzed from January 2023 to June 2023. Exposures: Models to estimate the 1-year and 2-year risk of cardiovascular death or hospitalization for heart failure, cardiovascular death, and all-cause death. Results: Data from 6263 individuals in the DELIVER trial were used to derive the prediction model and data from 4796 individuals in the PARAGON-HF trial and 4128 individuals in the I-PRESERVE trial were used to validate it. The final prediction model for the composite outcome included 11 variables: N-terminal pro-brain natriuretic peptide (NT-proBNP) level, HFH within the past 6 months, creatinine level, diabetes, geographic region, HF duration, treatment with a sodium-glucose cotransporter 2 inhibitor, chronic obstructive pulmonary disease, transient ischemic attack/stroke, any previous HFH, and heart rate. This model showed good discrimination (C statistic at 1 year, 0.73; 95% CI, 0.71-0.75) in both validation cohorts (C statistic at 1 year, 0.71; 95% CI, 0.69-0.74 in PARAGON-HF and 0.75; 95% CI, 0.73-0.78 in I-PRESERVE) and calibration. The model showed similar discrimination to a biomarker-driven model including high-sensitivity cardiac troponin T and significantly better discrimination than the Meta-Analysis Global Group in Chronic (MAGGIC) risk score (C statistic at 1 year, 0.60; 95% CI, 0.58-0.63; delta C statistic, 0.13; 95% CI, 0.10-0.15; P <.001) and NT-proBNP level alone (C statistic at 1 year, 0.66; 95% CI, 0.64-0.68; delta C statistic, 0.07; 95% CI, 0.05-0.08; P <.001). Models derived for the prediction of all-cause and cardiovascular death also performed well. An online calculator was created to allow calculation of an individual's risk. Conclusions and Relevance: In this prognostic study, a robust prediction model for clinical outcomes in HFpEF was developed and validated using routinely collected variables. The model performed better than NT-proBNP level alone. The model may help clinicians to identify high-risk patients and guide treatment decisions in HFpEF..
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24.
  • Rollauer, Sarah E., et al. (författare)
  • Structure of the TatC core of the twin-arginine protein transport system
  • 2012
  • Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 492:7428, s. 210-
  • Tidskriftsartikel (refereegranskat)abstract
    • The twin-arginine translocation (Tat) pathway is one of two general protein transport systems found in the prokaryotic cytoplasmic membrane and is conserved in the thylakoid membrane of plant chloroplasts. The defining, and highly unusual, property of the Tat pathway is that it transports folded proteins, a task that must be achieved without allowing appreciable ion leakage across the membrane. The integral membrane TatC protein is the central component of the Tat pathway. TatC captures substrate proteins by binding their signal peptides. TatC then recruits TatA family proteins to form the active translocation complex. Here we report the crystal structure of TatC from the hyperthermophilic bacterium Aquifex aeolicus. This structure provides a molecular description of the core of the Tat translocation system and a framework for understanding the unique Tat transport mechanism.
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25.
  • Thornton, Jeff W., et al. (författare)
  • Residential vertical geothermal heat pump system models : calibration to data
  • 1997
  • Ingår i: Technical and symposium papers presented at the 1997 annual meeting. - Atlanta, Ga. : American Society of Heating, Refrigerating, and Air-Conditioning Engineers. ; , s. 660-674
  • Konferensbidrag (refereegranskat)abstract
    • A detailed component-based simulation model of a geothermal heat pump system has been calibrated to monitored data taken from a family housing unit located at Fort Polk, Louisiana. The simulation model represents the housing unit, geothermal heat pump, ground heat exchanger, thermostat, blower, and ground-loop pump. Each of these component models was "tuned" to better match the measured data from the site. These tuned models were then interconnect to form the system model. The system model was then exercised in order to demonatrate its capabilities.
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