The Fluvial Reworking of Late Pleistocene Drift, Squamish River Drainage Basin, Southwestern British Colombia

Reworked glacial sediment(s) (RGS) represents the component of paraglacial sedimentation derived from the fluvial reworking of late Pleistocene glacial deposits in the postglacial landscape. In Squamish River drainage basin, southwestern British Columbia, the primary source of the RGS transferred to Squamish Valley is fluvial incision into valley-fill deposits in the five major tributary valleys of the watershed. The total volume of RGS transferred to Squamish Valley is 415 x 106m3. The volume of RGS from the individual tributary valleys range from 6 to 130 x 106m3 with valley morphology and late Quaternary history being the important controls upon the specific amount. Geomorphic evidence indicates that the bulk of the RGS was contributed to Squamish Valley thousands of years ago. The transfer of RGS continues at a very low residual rate in the contemporary landscape. RGS appear to represent a minor portion of the Squamish valley-fill and a small component of the postglacial sediments stored in Squamish Valley.Les sédiments glaciaires remaniés sont une composante de la sédimentation périglaciaire issue du remaniement fluviatile des dépôts glaciaires dans le paysage postglaciaire. Dans le bassin versant de la Squamish River, la principale source de sédiments glaciaires remaniés provient d'un encaissement fluvial dans les matériaux de remblaiement des cinq principales vallées tributaires du bassin-versant. La quantité de matériaux transportée de ces vallées tributaires à la vallée Squamish est de 415 x 106m3. Les volumes impliqués à partir de chacune des vallées varient de 6 à 130 x 106m3, la morphologie de la vallée et le type d'évolution au Quaternaire supérieur étant les principaux facteurs intervenant dans les quantités exportées. Les données géomorphologiques démontrent que la plus grande partie de l'apport sédimentaire était déjà répartie dans la vallée Squamish il y a des milliers d'années, mais qu'il se poursuit à un taux résiduel dans le paysage actuel. Les dépôts glaciaires remaniés représentent une composante mineure de l'approvisionnement de sédiments postglaciaires dans la vallée de la Squamish River.Umgestaltete glaziale Sedimente sind ein Bestandteil der paragiazialen Sedimentierung, die aus der fluviatilen Umgestaltung glazialer Ablagerungen des spàten Pleistozâns in der postglazialen Landschaft hervorgegangen ist. Im Emahrungsbecken des Squamish River, sùdwestliches British Columbia, ist die Hauptquelle der zum Squamish-Tal transportierten umgearbeiteten glazialen Sedimente fluviatiles Ein-schneiden in die Talaufschùttungsablagerungen in den fùnf wichtigsten Nebentàlern des Flussbeckens. Das gesamte Volumen der zum Squamish-Tal transportierten umgestalteten glazialen Sedimente betràgt 415 x 106m3. Das Volumen des Materials von den einzelnen Nebentàlern reicht von 6 bis 130 x 106m3, wobei Talmorphologie und Geschichte im spàten Quaternàr die wichtigen Kontrollfaktoren fur die jeweilige Menge darstellen. Geomorphologische Daten zeigen, dass der grôsste Teil der umgestalteten glazialen Ablagerungen schon vor mehreren tausend Jahren im Squamish-Tal verteilt war. Der Transport dieses Materials setzt sich in der gegenwârtigen Landschaft in einer sehr niedrigen Rùckstandsrate fort. Umgestaltete glaziale Sedimente scheinen einen gering-fugigen Teil der Squamish-Talauffullung auszumachen und sind ein kleiner Bestandteil der im Squamish-Tal gelagerten postglazialen Sedimente

Deposits and Cutoff Ages of Horseshoe and Marion Oxbow Lakes, Red River, Manitoba

Horseshoe Lake and the Marion Lake scar, along the Red River, southern Manitoba, were cored to investigate the timing of the meander cutoffs and the sedimentology of the channel in-fill deposits. The Horseshoe Lake core, 10.75 m long, consists of 9.73 m of silt-rich deposits inferred to be lacustrine from 0 to 4 m deep, transitional from 4 to 5 m deep and alluvial below 5 m deep. Four wood and charcoal specimens sampled from the core yielded radiocarbon ages of 310 ± 40, 1730 ± 50, 2040 ± 50 and 2240 ± 50 BP. The Marion Lake core, 16.77 m long, consists of 14.73 m of silt-rich deposits inferred to be lacustrine from 0 to 5 m deep and alluvial below 8.5 m deep; the transition is indistinct and falls between 5 to 8.5 m deep. Four wood samples from the fluvial deposits yielded radiocarbon ages of 1600 ± 40, 1700 ± 40, 1660 ± 40 and 1620 ± 40 BP. The cutoffs that led to the formation of Horseshoe and Marion lakes are interpreted to have occurred at ~1990 and ~1520 cal BP or shortly thereafter, respectively. The silt-rich, alluvial-lacustrine deposits in the lakes lack structural and textural characteristics that can be readily recognized in core to distinguish the depositional environments. The absence of coarse sediments at the base of the fluvial units at both sites implies that minor to negligible amounts of sand were transported along the thalwegs of the channels prior to the meanders being cutoff. The dominance of silt within the oxbow deposits reflects sediment supply as the geomorphic setting of the river is within an extensive glaciolacustrine clay plain.Le lac Horseshoe et l'ancien lac Marion ont fait l'objet de carottages dans le but d'établir le moment du recoupement de leur méandre et la sédimentologie des dépôts accumulés dans leur chenal. La carotte du lac Horseshoe (10,75 m) est constituée de 9,73 m de dépôts riches en limon, probablement lacustres entre 0 et 4 m de profondeur, de transition entre 4 et 5 m et alluviaux sous les 5 m. Quatre échantillons de bois et de charbon ont donné des âges au radiocarbone de 310 ± 40, 1730 ± 50, 2040 ± 50 et 2240 ± 50 BP. La carotte du lac Marion (16,77 m) est constituée de 14,73 m de dépôts riches en limon, apparemment lacustres entre 0 et 5 m et alluviaux sous les 8,5 m ; la transition, mal définie, se situe entre 5 et 8,5 m de profondeur. Quatre échantillons de bois provenant des dépôts fluviatiles ont donné des âges au radiocarbone de 1600 ± 40, 1700 ± 40, 1660 ± 40 et 1620 ± 40 BP. On estime que les recoupements qui ont donné naissance aux deux lacs se sont produits il y a environ 1990 (Horseshoe) et 1520 cal. BP (Marion), ou peu après. Les dépôts alluvio-lacustres riches en limon des lacs ne comportent pas de structures et de textures assez nettes pour permettre d’identifier leur milieux de sédimentation. L'absence, dans les deux cas, de sédiments grossiers à la base de l'unité fluviatile laisse supposer que des quantités minimes, voire négligeables, de sable ont été transportées le long des thalwegs avant que les recoupements ne surviennent. La prédominance du limon dans les dépôts des lacs en croissant reflète la provenance des sédiments, le cadre géomorphologique de la rivière étant celui d’une vaste plaine d'argile glaciolacustre.Los sedimentos de los lagos Horseshoe y Marion situados a lo largo del río Red al sur de Manitoba fueron estudiados para establecer la fecha de formación de meandros y la sedimentología de los depósitos de los canales. El núcleo testigo de sondeo proveniente del lago Horseshoe, de 10,75 m de largo, está compuestos de depósitos ricos en limo de hasta 9,73 m. Dichos depósitos son considerados como de origen lacustre en una región de 0 a 4 m de profundidad, de tipo de transición entre 4 y 5 m de profundidad y de origen aluvial por debajo de 5 m de profundidad. Cuatro especímenes de madera y de carbón obtenidos de dicho núcleo testigo fueron datados con radiocarbono proporcionando un edad cercana a los 310 ± 40, 1730 ± 50, 2040 ± 50 y 2240 ± 50 años BP. El núcleo testigo de sondeo de 16,77 m de largo proveniente del lago Marion, esta compuesto de una zona que abarca 14.73 m de depósitos arcillosos de origen lacustre entre 0-5 m de profundidad y de origen aluvial por debajo de los 8.5 m de profundidad; la zona de transición se sitúa entre 5 y 8.5 m de profundidad pero no se encuentra bien definida. La datación con radiocarbono de cuatro muestras de depósitos fluviales proporciono una edad que las sitúa hace unos 1600 ± 40, 1660 ± 40 y 1620 ± 40 años BP. Se cree que el corte de terreno que dio origen a la formación de los lagos Horseshoe y Marion ocurrió hace unos 19 900 a 15 200 años o poco tiempo después, respectivamente. Los depósitos ricos en limo de origen lacustre-aluvial de los lagos carecen de las características estructurales y de textura que pueden ser reconocidos fácilmente en el núcleo testigo para distinguir los ambientes de depósito. La ausencia de sedimentos de tipo grueso en la base de la unidad fluvial en ambos sitios indica que un aporte pequeño o insignificante de arena fue transportado a lo largo de la vaguada de los canales antes de que ocurriera la formación de los meandros. La predominancia de limos entre los depósitos del brazo muerto refleja el origen de los sedimentos y concuerda con el cuadro geomorfológico de un rió situado dentro de una planicie arcillosa glaciolacustre muy extensa

Improving Mechanical Ventilator Clinical Decision Support Systems with A Machine Learning Classifier for Determining Ventilator Mode

Clinical decision support systems (CDSS) will play an in-creasing role in improving the quality of medical care for critically ill patients. However, due to limitations in current informatics infrastructure, CDSS do not always have com-plete information on state of supporting physiologic monitor-ing devices, which can limit the input data available to CDSS. This is especially true in the use case of mechanical ventilation (MV), where current CDSS have no knowledge of critical ventilation settings, such as ventilation mode. To enable MV CDSS to make accurate recommendations related to ventilator mode, we developed a highly performant ma-chine learning model that is able to perform per-breath clas-sification of 5 of the most widely used ventilation modes in the USA with an average F1-score of 97.52%. We also show how our approach makes methodologic improvements over previous work and that it is highly robust to missing data caused by software/sensor error

Overview of the 2007 and 2008 campaigns conducted as part of the Greenland Summit Halogen-HO\u3csub\u3ex\u3c/sub\u3e Experiment (GSHOX)

From 10 May through 17 June 2007 and 6 June through 9 July 2008 intensive sampling campaigns at Summit, Greenland confirmed that active bromine chemistry is occurring in and above the snow pack at the highest part of the Greenland ice sheet (72°36´ N, 38°25´ W and 3.2 km above sea level). Direct measurements found BrO and soluble gas phase Br− mixing ratios in the low pptv range on many days (maxima \u3c 10 pptv). Conversion of up to 200 pg m−3 of gaseous elemental mercury (GEM) to reactive gaseous mercury (RGM) and enhanced OH relative to HO2 plus RO2 confirm that active bromine chemistry is impacting chemical cycles even at such low abundances of reactive bromine species. However, it does not appear that Bry chemistry can fully account for observed perturbations to HOx partitioning, suggesting unknown additional chemical processes may be important in this unique environment, or that our understanding of coupled NOx-HOx-Brychemistry above sunlit polar snow is incomplete. Rapid transport from the north Atlantic marine boundary layer occasionally caused enhanced BrO at Summit (just two such events observed during the 12 weeks of sampling over the two seasons). In general observed reactive bromine was linked to activation of bromide (Br−) in, and release of reactive bromine from, the snowpack. A coupled snow-atmosphere model simulated observed NO and BrO at Summit during a three day interval when winds were weak. The source of Br− in surface and near surface snow at Summit is not entirely clear, but concentrations were observed to increase when stronger vertical mixing brought free tropospheric air to the surface. Reactive Bry mixing ratios above the snow often increased in the day or two following increases in snow concentration, but this response was not consistent. On seasonal time scales concentrations of Br− in snow and reactive bromine in the air were directly related

Enhancements in Glovebox Design Resulting from Laboratory-Conducted FIre Tests

The primary mission of the Pit Disassembly and Conversion Facility (PDCF) Project was to disassemble nuclear weapons pits and convert the resulting special nuclear materials to a form suitable for further disposition. Because of the nature of materials involved, the fundamental system which allowed PDCF to perform its mission was a series of integrated and interconnected gloveboxes which provided confinement and containment of the radioactive materials being processed. The high throughput planned for PDCF and the relatively high neutron and gamma radiation levels of the pits required that gloveboxes be shielded to meet worker dose limits. The glovebox shielding material was required to contain high hydrogen concentrations which typically result in these materials being combustible. High combustible loadings created design challenges for the facility fire suppression and ventilation system design. Combustible loading estimates for the PDCF Plutonium (Pu) Processing Building increased significantly due to these shielding requirements. As a result, the estimates of combustible loading substantially exceeded values used to support fire and facility safety analyses. To ensure a valid basis for combustible loading contributed by the glovebox system, the PDCF Project funded a series of fire tests conducted by the Southwest Research Institute on door panels and a representative glovebox containing Water Extended Polyester (WEP) radiological shielding to observe their behavior during a fire event. Improvements to PDCF glovebox designs were implemented based on lessons learned during the fire test. In particular, methods were developed to provide high levels of neutron shielding while maintaining combustible loading in the glovebox shells at low levels. Additionally, the fire test results led to design modifications to mitigate pressure increases observed during the fire test in order to maintain the integrity of the WEP cladding. These changes resulted in significantly reducing the credited combustible loading of the facility. These advances in glovebox design should be considered for application in nuclear facilities within the Department of Energy complex in the future

Bayesian analysis of exoplanet and binary orbits

We introduce BASE (Bayesian astrometric and spectroscopic exoplanet detection and characterisation tool), a novel program for the combined or separate Bayesian analysis of astrometric and radial-velocity measurements of potential exoplanet hosts and binary stars. The capabilities of BASE are demonstrated using all publicly available data of the binary Mizar A.Comment: Accepted for publication in Astronomy & Astrophysic

Wintering Eiders Acquire Exceptional Se and Cd Burdens in the Bering Sea: Physiological and Oceanographic Factors

During late winter (March) in the Bering Sea, levels of Se in livers and Cd in kidneys of spectacled eiders Somateria fischeri were exceptionally high (up to 489 and 312 µg g−1 dry mass, respectively). Comparison of organ and blood samples during late winter, early spring migration, and breeding suggests that the eiders’ high Se and Cd burdens were accumulated at sea, with highest exposure during winter. High exposure may have resulted from high metabolic demands and food intake, as well as concentrations in food. In the eiders’ remote wintering area, their bivalve prey contained comparable Se levels and much higher Cd levels than in industrialized areas. Patterns of chlorophyll a in water and sediments indicated that phytoplankton detritus settling over a large area was advected into a persistent regional eddy, where benthic prey densities were higher than elsewhere and most eider foraging occurred. Se and Cd assimilated or adsorbed by bloom materials apparently also accumulated in the eddy, and were incorporated into the bivalve prey of eiders. Atmospheric deposition of dust-borne trace elements from Asia, which peaks during the ice-edge phytoplankton bloom from March to May, may augment processes that concentrate Se and Cd in eider prey. Compared with freshwater birds, some sea ducks (Mergini) accumulate much higher concentrations of trace elements, even with the same levels in food, with no apparent ill effects. Nevertheless, the absolute and relative burdens of different elements in sea ducks vary greatly among areas. Our results suggest these patterns can result from (1) exceptional accumulation and tolerance of trace elements when exposure is elevated by high food intake or levels in food, and (2) atmospheric and oceanographic processes that concentrate trace elements in local benthic food webs