Open ocean carbon monoxide photo-production

Sunlight-initiated photolysis of chromophoric dissolved organic matter (CDOM) is the dominant source of carbon monoxide (CO) in the open-ocean. A modelling study was conducted to constrain this source. Spectral solar irradiance was obtained from two models (GCSOLAR and SMARTS2). Water-column CDOM and total light absorption were modelled using spectra collected along a Meridional transect of the Atlantic ocean using a 200-cm pathlength liquid waveguide UV-visible spectrophotometer. Apparent quantum yields for the production of CO (AQYCO) from CDOM were obtained from a parameterisation describing the relationship between CDOM light absorption coefficient and AQYCO and the CDOM spectra collected. The sensitivity of predicted rates to variations in model parameters (solar irradiance, cloud cover, surface-water reflectance, CDOM and whole water light absorbance, and AQYCO was assessed. The model\u27s best estimate of open-ocean CO photoproduction was 47 +/- 7 Tg CO-C yr-1, with lower and upper limits of 38 and 84 Tg CO-C yr-1, as indicated by sensitivity analysis considering variations in AQYs, CDOM absorbance, and spectral irradiance. These results represent significant constraint of open-ocean CO photoproduction at the lower limit of previous estimates. Based on these results, and their extrapolation to total photochemical organic carbon mineralisation, we recommend a downsizing of the role of photochemistry in the open-ocean carbon cycle. (c) 2006 Elsevier Ltd. All rights reserved

Extent of microplastics in Pacific Sand Lance burying habitat in the Salish Sea

Extent of microplastics in Pacific Sand Lance burying habitat in the Salish Sea Willem Peters MRM candidate Simon Fraser University, Dr. Cliff Robinson Department of Fisheries and Oceans, Dr. Karen Kohfeld Simon Fraser University, Dr. Marlow Pellatt Parks Canada, Dr. Doug Bertram Environment and Climate Change Canada School of Resource and Environmental Management, Simon Fraser University, 8888 University Drive, Burnaby, BC V5A 1S6 CANADA, [email protected] The ingestion of microplastics by forage fish and their subsequent accumulation and transfer up the coastal food web is a growing concern to scientists, government, fisheries, and the health sector. One key forage species in the Salish Sea, the Pacific sand lance (Ammodytes personatus), buries in low silt, medium coarse sand patches from chart datum to 100 m depth. In the southern Salish Sea near Sidney, several of these burying habitats are located in the vicinity of sewage discharge pipes and may be subject to microplastic accumulation. This research assesses the level of microplastic accumulation in Pacific sand lance burying habitats in the Salish Sea. Seafloor sediment samples were collected in Spring-Fall 2017, using a Van Veen grab sampler. Samples were collected at different distances from shore and effluent discharge pipes, and from a variety of depths and tidal currents. Microplastic concentrations were determined from the sediment samples in the laboratory using standard methods, while controlling for contamination. The main results indicate a significant correlation between suitable Pacific sand lance burying habitat and higher microplastic concentrations. We also found a strong imbalance of microplastic type and colour, with blue fibres making up the majority of microplastics found. The relationship between microplastics and Pacific sand lance habitat suitability is not intuitive in that higher concentrations of microplastics were found in sediments that suggest higher current rates, where settling dynamics would suggest that fewer particles would settle. Possible explanations include evacuation of microplastics from sand lance when buried, the proximity of suitable habitat to effluent discharge, or other as yet unexplored factors. Overall, the presence of microplastics in the burying habitats and stomachs of Pacific sand lance (as noted in other research) indicates more research is required to understand the implication to higher trophic level species that feed upon Pacific sand lance, such as chinook and coho salmon, various groundfish, fish-eating alcids, and marine mammals such as the humpback whale. Ultimately, strategies to reduce microplastics entering the Salish Sea will need to be implemented

Formal Concept Lattice Representations and Algorithms for Hypergraphs

There is increasing focus on analyzing data represented as hypergraphs, which are better able to express complex relationships amongst entities than are graphs. Much of the critical information about hypergraph structure is available only in the intersection relationships of the hyperedges, and so forming the "intersection complex" of a hypergraph is quite valuable. This identifies a valuable isomorphism between the intersection complex and the "concept lattice" formed from taking the hypergraph's incidence matrix as a "formal context": hypergraphs also generalize graphs in that their incidence matrices are arbitrary Boolean matrices. This isomorphism allows connecting discrete algorithms for lattices and hypergraphs, in particular s-walks or s-paths on hypergraphs can be mapped to order theoretical operations on the concept lattice. We give new algorithms for formal concept lattices and hypergraph s-walks on concept lattices. We apply this to a large real-world dataset and find deep lattices implying high interconnectivity and complex geometry of hyperedges

Verification of Experimental Techniques for Flow Surface Determination

The concept of a yield surface is central to the mathematical formulation of a classical plasticity theory. However, at elevated temperatures, material response can be highly time-dependent, which is beyond the realm of classical plasticity. Viscoplastic theories have been developed for just such conditions. In viscoplastic theories, the flow law is given in terms of inelastic strain rate rather than the inelastic strain increment used in time-independent plasticity. Thus, surfaces of constant inelastic strain rate or flow surfaces are to viscoplastic theories what yield surfaces are to classical plasticity. The purpose of the work reported herein was to validate experimental procedures for determining flow surfaces at elevated temperatures. Since experimental procedures for determining yield surfaces in axial/torsional stress space are well established, they were employed -- except inelastic strain rates were used rather than total inelastic strains. In yield-surface determinations, the use of small-offset definitions of yield minimizes the change of material state and allows multiple loadings to be applied to a single specimen. The key to the experiments reported here was precise, decoupled measurement of axial and torsional strain. With this requirement in mind, the performance of a high-temperature multi-axial extensometer was evaluated by comparing its results with strain gauge results at room temperature. Both the extensometer and strain gauges gave nearly identical yield surfaces (both initial and subsequent) for type 316 stainless steel (316 SS). The extensometer also successfully determined flow surfaces for 316 SS at 650 C. Furthermore, to judge the applicability of the technique for composite materials, yield surfaces were determined for unidirectional tungsten/Kanthal (Fe-Cr-Al)

Treatment utilization and outcomes in elderly patients with locally advanced esophageal carcinoma: A review of the National Cancer Database

For elderly patients with locally advanced esophageal cancer, therapeutic approaches and outcomes in a modern cohort are not well characterized. Patients ≥70 years old with clinical stage II and III esophageal cancer diagnosed between 1998 and 2012 were identified from the National Cancer Database and stratified based on treatment type. Variables associated with treatment utilization were evaluated using logistic regression and survival evaluated using Cox proportional hazards analysis. Propensity matching (1:1) was performed to help account for selection bias. A total of 21,593 patients were identified. Median and maximum ages were 77 and 90, respectively. Treatment included palliative therapy (24.3%), chemoradiation (37.1%), trimodality therapy (10.0%), esophagectomy alone (5.6%), or no therapy (12.9%). Age ≥80 (OR 0.73), female gender (OR 0.81), Charlson-Deyo comorbidity score ≥2 (OR 0.82), and high-volume centers (OR 0.83) were associated with a decreased likelihood of palliative therapy versus no treatment. Age ≥80 (OR 0.79) and Clinical Stage III (OR 0.33) were associated with a decreased likelihood, while adenocarcinoma histology (OR 1.33) and nonacademic cancer centers (OR 3.9), an increased likelihood of esophagectomy alone compared to definitive chemoradiation. Age ≥80 (OR 0.15), female gender (OR 0.80), and non-Caucasian race (OR 0.63) were associated with a decreased likelihood, while adenocarcinoma histology (OR 2.10) and high-volume centers (OR 2.34), an increased likelihood of trimodality therapy compared to definitive chemoradiation. Each treatment type demonstrated improved survival compared to no therapy: palliative treatment (HR 0.49) to trimodality therapy (HR 0.25) with significance between all groups. Any therapy, including palliative care, was associated with improved survival; however, subsets of elderly patients with locally advanced esophageal cancer are less likely to receive aggressive therapy. Care should be taken to not unnecessarily deprive these individuals of treatment that may improve survival

Instructional strategies to promote incremental beliefs in youth sport

Implicit beliefs about the nature of human abilities have significant motivational, behavioral, and affective consequences. The purpose of this article was to review the application of implicit beliefs to the youth sport context and to provide theoretically derived and evidence-based instructional strategies to promote adaptive implicit beliefs about human abilities within this context. A narrative overview of theory and a review of research pertaining to implicit beliefs in education, sport, and physical activity are undertaken. Theoretically derived and evidence-based instructional strategies are outlined, and specific coaching behaviors are suggested. Six instructional strategies to promote adaptive implicit beliefs in these contexts are suggested: focusing on effort and persistence, facilitating challenge, promoting the value of failure, defining success as effort, the promotion of learning, and providing high expectations. It is concluded that instructional strategies may be used to facilitate positive motivational, behavioral, and affective outcomes for young people within a sport context