38 research outputs found
Pliocene and pleistocene volcanic interaction with cordilleran ice sheets, damming of the Yukon River and vertebrate palaeontology, Fort Selkirk volcanic group, west-central Yukon, Canada
Romeo Sherpa green journal. Permission to archive accepted author manuscriptNeogene volcanism in the Fort Selkirk area began with eruptions in the Wolverine Creek basin ca. 4.3 Ma
and persisted to ca. 3.0 Ma filling the ancestral Yukon River valley with at least 40 m of lava flows.
Activity at the Ne Châe DdhĂ€wa eruptive center overlapped with the last stages of the Wolverine Creek
eruptive centers. Hyaloclastic tuff was erupted between ca. 3.21 and 3.05 Ma. This eruption caused or
was coincident with damming of Yukon River. The first demonstrable incursion of a Cordilleran ice sheet
into the Fort Selkirk area was coincident with a second eruption of the Ne Châe DdhĂ€wa eruptive center
ca. 2.1 Ma. The Ne Châe DdhĂ€wa subglacial mound was erupted beneath at least 300 m of glacial ice (Ne
Châe DdhĂ€wa Glaciation). The Eruption of the Fort Selkirk center occurred between the last eruption of
Ne Châe DdhĂ€wa and Fort Selkirk Glaciation (ca. 2.1e1.5 Ma). Till and outwash from Fort Selkirk Glaciation
are conformably overlain by nonglacial sediments that contain the Fort Selkirk tephra (fission track
dated at ca. 1.5 Ma). These nonglacial sediments also preserve a short magnetic reversal (reversed to
normal) identified as the GilsĂĄ polarity excursion. Temporal control and sedimentology constrain Fort
Selkirk Glaciation and the Fort Selkirk Local Fauna to marine isotope stage 54. Rapid and extensive
eruption of the Pelly eruptive center filled the Yukon River valley with 70 m of lava which buried these
glacial and nonglacial sediments and dammed Yukon River. Local striations and erratic pebbles occur on
the last of these lava flows. They document a subsequent incursion of glacial ice during the last 500 ka of
the Matuyama Chron (Forks Glaciation). The last major eruption of mafic lava occurred in the middle
Pleistocene west of (early Holocene) Volcano Mountain in basin of Black Creek: lava flowed down the
valley presently occupied by Black Creek and dammed Yukon River in the area of the Black Creek
confluence. This eruption predated the middle Pleistocene Reid Glaciation. Minor volcanism has
continued in this area since the middle Pleistocene at Volcano Mountain.Ye
A Review of the fossil record of turtles of the clade Baenidae
The fossil record of the turtle clade Baenidae ranges from the Early Cretaceous (AptianâAlbian) to the Eocene. The group is present throughout North America during the Early Cretaceous, but is restricted to the western portions of the continents in the Late Cretaceous and Paleogene. No credible remains of the clade have been reported outside of North America to date. Baenids were warmadapted freshwater aquatic turtles that supported high levels of diversity at times through niche partitioning, particularly by adapting to a broad range of dietary preferences ranging from omnivorous to molluscivorous. Current phylogenies place Baenidae near the split of crown-group Testudines. Within Baenidae three more inclusive, named clades are recognized: Baenodda, Palatobaeninae and Eubaeninae. A taxonomic review of the group concludes that of 49 named taxa, 30 are nomina valida, 12 are nomina invalida and 7 are nomina dubia
The Atacama Cosmology Telescope: A Catalog of >4000 SunyaevâZelâdovich Galaxy Clusters
We present a catalog of 4195 optically confirmed SunyaevâZel'dovich (SZ) selected galaxy clusters detected with signal-to-noise ratio >4 in 13,211 deg2 of sky surveyed by the Atacama Cosmology Telescope (ACT). Cluster candidates were selected by applying a multifrequency matched filter to 98 and 150 GHz maps constructed from ACT observations obtained from 2008 to 2018 and confirmed using deep, wide-area optical surveys. The clusters span the redshift range 0.04 1 clusters, and a total of 868 systems are new discoveries. Assuming an SZ signal versus mass-scaling relation calibrated from X-ray observations, the sample has a 90% completeness mass limit of M500c > 3.8 Ă 1014 Mâ, evaluated at z = 0.5, for clusters detected at signal-to-noise ratio >5 in maps filtered at an angular scale of 2farcm4. The survey has a large overlap with deep optical weak-lensing surveys that are being used to calibrate the SZ signal mass-scaling relation, such as the Dark Energy Survey (4566 deg2), the Hyper Suprime-Cam Subaru Strategic Program (469 deg2), and the Kilo Degree Survey (825 deg2). We highlight some noteworthy objects in the sample, including potentially projected systems, clusters with strong lensing features, clusters with active central galaxies or star formation, and systems of multiple clusters that may be physically associated. The cluster catalog will be a useful resource for future cosmological analyses and studying the evolution of the intracluster medium and galaxies in massive clusters over the past 10 Gyr
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Transport of Vacuum Arc Plasma Through Straight and Curved Magnetic Ducts
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Transport of Vacuum Arc Plasma Through Straight and Curved Magnetic Ducts
Nodular silcretes of the Cypress Hills Formation (upper Eocene to middle Miocene) of southern Saskatchewan, Canada
Leporids (Mammalia, Lagomorpha) from the Diamond O Ranch Local Fauna, Latest Middle Eocene of Southwestern Montana
Design and Validation of an Augmented Hematopoietic Cell Transplantation-Comorbidity Index Comprising Pretransplant Ferritin, Albumin, and Platelet Count for Prediction of Outcomes after Allogeneic Transplantation
Pretransplant values of serum ferritin, albumin, and peripheral blood counts were previously suggested to provide prognostic information about hematopoietic cell transplantation (HCT) outcomes. Whether these "biomarkers" have prognostic value independent of each other and the HCT-comorbidity index (HCT-CI) is unknown. We analyzed data from 3917 allogeneic HCT recipients at multiple sites in the United States and Italy using multivariate models including each biomarker and the HCT-CI. Data from all sites were then randomly divided into a training set (n= 2352) to develop weights for the relevant biomarkers to be added to the HCT-CI scores and a validation set (n= 1407) to validate an augmented HCT-CI compared with the original index. Multivariate analysis with data from one site showed that ferritin, albumin, and platelets-not neutrophils or hemoglobin-were independently associated with increased nonrelapse mortality (NRM) and decreased overall survival. Findings were validated in data from the other sites. Subsequently, in a training set from all sites, ferritin >2500 mg/dL (hazard ratio [HR], 1.69); albumin 3 to 3.5 g/dL (HR, 1.61) and <3.0 g/dL (HR, 2.27); and platelets 50 to <100,000 (HR, 1.28), 20 to <50,000 (HR, 1.29), and <20,000 (HR, 1.55) were statistically significantly associated with NRM. Weights were assigned to these laboratory values following the same equation used to design the original index. In the validation set, the addition of the biomarkers to the original index to develop an augmented HCT-CI resulted in a statistically significant increase in a higher c-statisticestimate for prediction of NRM (P=.0007). Ferritin, albumin, and platelet counts are important prognostic markers that further refine the discriminative power of the HCT-CI for transplant outcomes