19 research outputs found
Age of Rotational Landslides in the Cypress Hills, Alberta-Saskatchewan
The topography of the west block of the Cypress Hills indicates that fluvial dissection of the plateaux and subsequent rotational landsliding of valley sides have been the dominant Quaternary geomorphic processes. This paper presents a preliminary chronology of rotational landslides based on the relative ages of 17 landslides and on 3 absolute dates. Four indices of relative age were used: organic content in Ah and B soil horizons, the size and coverage of lichens and weathering rind thickness on boulders exposed by landsliding, and the concavity and gradient of gullies in landslide debris, One landslide occurred in 1965. Organic materials collected from buried soil horizons beneath depressions on 3 other landslides were radiocarbon dated at 1235 ± 105, 1635 ± 105 and 7259 ± 165 yrs. BP. Microscopic analysis of the organic material revealed that the oldest sample was contaminated with older carbon. Cluster analysis of the relative age data in conjunction with 3 acceptable absolute dates suggests that the landslides under study have occurred during late Holocene time.La topographie du secteur ouest des Cypress Hills révèle qu'au Quaternaire les principaux processus géomorphologiques ont été l'érosion fluviatile, sur les plateaux, et les glissements de terrain par rotation, sur les versants. Le présent article propose une chronologie des glissements de terrain, 17 ayant une datation relative, et 3, une datation absolue. Quatre indices ont été utilisés pour déterminer l'âge relatif: la teneur en matière organique des horizons pédologiques Ah et B, la concavité et la pente des ravins creusés dans les matériaux, la taille des lichens et Ia surface qu'ils occupent sur des blocs mis au jour par les glissements de terrain, ainsi que l'épaisseur de la couche altérée sur ces blocs. Il y eut un glissement en 1965. À la suite du prélèvement de matière organique dans des horizons pédologiques enfouis, on a pu dater au radiocarbone trois autres glissements (1235 ± 105; 1635 ± 105; 7259 ± 165 BP). L'analyse des échantillons au microscope révèle que Ia matière organique la plus ancienne renfermait du carbone. Une analyse d'ensemble (datations relatives et absolues) laisse penser que les glissements de terrain se sont produits à la fin de l'Holocène.Die Topographie des Westteils der Cypress Hills IaBt erkennen, daB die fluviatile Gliederung der Plateaus und anschlieBende Erdrutsche der Talseiten die wichtigsten geomorphologischen Prozesse im Quaternâr gewesen sind. Dieser Artikel gibt eine vorlâufige Chronologie der Erdrutsche, gestùtzt auf die relative Datierung von 17 Erdrutschen und auf drei absolute Datierungen. Vier Anhaltspunkte wurden fur die relative Datierung benutzt: Der organische Gehalt in den Ah und B Boden-Horizonten, die GrôBe und Ausdehnung der Flechten und die Dicke der Verwitterungskruste auf den durch die Erdrutsche bloBgelegten Blôcken und die Hôhlung und Neigung der Rinnen in den Erdrutsch-Gesteinstrùmmern. Ein Erdrutsch ereignete sich 1965. Organisches Material, das aus vergrabenen Boden-Horizonten unterhalb der Senken von drei anderen Erdrutschen stammt, wurde mit Radiokarbon auf 1235 ± 105, 1635 ± 105 und 7259 ± 165 Jahre BP datiert. Die mikroskopische Analyse des organischen Materials lieB erkennen, daB die àlteste Probe àlteren Kohlenstoff enthielt. Eine Block-Analyse der relativen Datierungen im Zusammenhang mit den drei annehmbaren absoluten Datierungen legt nahe, daB die untersuchten Erdrutsche wâhrend des spâten Holozàn stattgefunden haben
Genome‐Wide Association Mapping for Leaf Tip Necrosis and Pseudo‐black Chaff in Relation to Durable Rust Resistance in Wheat
ECOSTRESS: NASA's next generation mission to measure evapotranspiration from the International Space Station
The ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station ECOSTRESS) was launched to the International Space Station on June 29, 2018. The primary science focus of ECOSTRESS is centered on evapotranspiration (ET), which is produced as level‐3 (L3) latent heat flux (LE) data products. These data are generated from the level‐2 land surface temperature and emissivity product (L2_LSTE), in conjunction with ancillary surface and atmospheric data. Here, we provide the first validation (Stage 1, preliminary) of the global ECOSTRESS clear‐sky ET product (L3_ET_PT‐JPL, version 6.0) against LE measurements at 82 eddy covariance sites around the world. Overall, the ECOSTRESS ET product performs well against the site measurements (clear‐sky instantaneous/time of overpass: r2 = 0.88; overall bias = 8%; normalized RMSE = 6%). ET uncertainty was generally consistent across climate zones, biome types, and times of day (ECOSTRESS samples the diurnal cycle), though temperate sites are over‐represented. The 70 m high spatial resolution of ECOSTRESS improved correlations by 85%, and RMSE by 62%, relative to 1 km pixels. This paper serves as a reference for the ECOSTRESS L3 ET accuracy and Stage 1 validation status for subsequent science that follows using these data
COSORE: A community database for continuous soil respiration and other soil‐atmosphere greenhouse gas flux data
Globally, soils store two to three times as much carbon as currently resides in the atmosphere, and it is critical to understand how soil greenhouse gas (GHG) emissions and uptake will respond to ongoing climate change. In particular, the soil‐to‐atmosphere CO2 flux, commonly though imprecisely termed soil respiration (RS), is one of the largest carbon fluxes in the Earth system. An increasing number of high‐frequency RS measurements (typically, from an automated system with hourly sampling) have been made over the last two decades; an increasing number of methane measurements are being made with such systems as well. Such high frequency data are an invaluable resource for understanding GHG fluxes, but lack a central database or repository. Here we describe the lightweight, open‐source COSORE (COntinuous SOil REspiration) database and software, that focuses on automated, continuous and long‐term GHG flux datasets, and is intended to serve as a community resource for earth sciences, climate change syntheses and model evaluation. Contributed datasets are mapped to a single, consistent standard, with metadata on contributors, geographic location, measurement conditions and ancillary data. The design emphasizes the importance of reproducibility, scientific transparency and open access to data. While being oriented towards continuously measured RS, the database design accommodates other soil‐atmosphere measurements (e.g. ecosystem respiration, chamber‐measured net ecosystem exchange, methane fluxes) as well as experimental treatments (heterotrophic only, etc.). We give brief examples of the types of analyses possible using this new community resource and describe its accompanying R software package
The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2
Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age 6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score 652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701