Koch E.W.,University of Alberta |
Koch E.W.,3333 University Way |
Bahramian A.,University of Alberta |
Heinke C.O.,University of Alberta |
And 13 more authors.
Monthly Notices of the Royal Astronomical Society | Year: 2014
We report observations using the Swift/XRT, NuSTAR, and Chandra X-ray telescopes of the transient X-ray source CXOGC J174540.0-290005 during its 2013 outburst. Due to its location in the field of multiple observing campaigns targeting Sgr A*, this is one of the best-studied outbursts of a very faint X-ray binary (VFXB; peak LX < 1036 erg s-1) yet recorded, with detections in 173 ks of X-ray observations over 50 d. VFXBs are of particular interest, due to their unusually low outburst luminosities and time-averaged mass transfer rates, which are hard to explain within standard accretion physics and binary evolution. The 2013 outburst of CXOGC J174540.0-290005 peaked at LX(2-10 keV) = 5.0 × 1035 erg s-1, and all data above 1034 erg s-1 were well fitted by an absorbed power law of photon index ∼1.7, extending from 2 keV out to ≳70 keV. We discuss the implications of these observations for the accretion state of CXOGC J174540.0-290005. © 2014 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society.
Mignerat M.,University of Ottawa |
Audebrand L.K.,3333 University Way
ICIS 2010 Proceedings - Thirty First International Conference on Information Systems | Year: 2010
Although the role of IT is salient in sporting mega-events (e.g. instant replay, goal-line technology), IS research has not yet paid any attention to the processes by which technologies are selected for and implemented at these mega-events, the strategies used by actors, nor the consequences of such implementations on actors in related sectors and industries. To tackle this underdeveloped research topic, we focus on the last three UEFA (Union of European Football Associations) soccer championships (2000, 2004, 2008) and we describe how some technologies are adopted (e.g., e-ticketing) while others (e.g., e-refereeing) are not. With an overall goal of deepening our understanding of IT-related institutional work surrounding mega-events in general and sporting mega-events in particular, our objective is to better comprehend the role and actions of institutional entrepreneurs in the selection and implementation of IT for sporting mega-events.
Siddiqua S.,3333 University Way |
Siemens G.,Royal Military College of Canada |
Blatz J.,University of Manitoba |
Man A.,Golder Associates |
Lim B.F.,Royal Military College of Canada
Geotechnical and Geological Engineering | Year: 2014
The producers of nuclear waste, within all countries exploring options, including Canada, have determined the long-term solution to be a deep geological repository. In the Canadian concept, within the deep geologic repository a number of clay-based barriers will separate the containers from the surrounding geosphere. Following placement the surrounding groundwater will infiltrate into the repository. In order to analyze the performance of the repository under very complex conditions, accurate material properties are required. The chemistry of the host rock is an important aspect as the behaviour of clay-based barrier materials could be affected by the saturating saline groundwater. This paper investigates the saturated mechanical behaviour of light backfill (composed of 50 % silica sand and 50 % Na-bentonite clay) and dense backfill (composed of 70 % crushed granite, 25 % glacial lake clay and 5 % Na-bentonite clay) and the quantifying the effect of pore fluid chemistry on the strength and compressibility behaviour of the materials. The results indicate that light backfill behaviour is strongly influenced by its pore fluid chemistry while dense backfill shows limited effects. The material parameters of light backfill and dense backfill are interpreted for input into numerical simulations. These results and interpretation enrich the understanding of the mechanical response of light and dense backfill, two components of the sealing system of the Canadian deep geologic repository. © 2014 Springer International Publishing Switzerland.
Greenough J.D.,3333 University Way |
Kamo S.L.,University of Toronto |
Theny L.,3333 University Way |
Crowe S.A.,University of Southern Denmark |
Fipke C.,Cf Mineral Research
Canadian Journal of Earth Sciences | Year: 2011
High-precision U-Pb isotope dilution - thermal ionization mass spectrometry (ID-TIMS) geochronology on chemically abraded zircon grains from a noritic gabbro of the Ni-bearing Suwar mafic-ultramafic layered complex, northwestern Yemen, gives a mean 206Pb/238U age of 638.46 ± 0.73 Ma (2s; MSWD = 1.4). At Wadi Qutabah, ~ 30 km to the north, a similar mafic sample has an identical age of 638.58 ± 0.51 Ma (2s; MSWD = 0.32), which supports the possibility of there being a single, large intrusive complex with an estimated areal extent of ~ 250 km2. This is supported by geochemical data of samples from each locality, which are postkinematic, gabbroic rocks that contain variable amounts of cumulus olivine, plagioclase, orthopyroxene, and ilmenite with intercumulus augite, hornblende, and Ni-sulphides. Straight rare Earth element (REE) patterns, Ba/La ~ 30, Rb/Ba ~ 0.04, and negative primitive-mantle-normalized P anomalies resemble EM1 (Enriched Mantle 1) of oceanic island basalts and Archean subcontinental mantle lithosphere. The mineralogy and magmatic/tectonic discrimination diagrams suggest within-plate continental tholeiitic and noritic cumulates typical of a rift setting for both intrusions. The complex intrudes retrograded, amphibolite-facies paragneiss of the Pan-African Afif lithotectonic terrane, and is generally undeformed and unaltered, and, therefore, unaffected by the Pan-African orogeny. Emplacement of the 639 Ma complex occurred during a tensional tectonic regime on the Arabian Peninsula and marks the time of proto-Iapetan rifting. The estimated size of the intrusion, its noritic composition, and Archean subcontinental lithospheric mantle signature and its position in thin Proterozoic lithosphere abutting Archean cratonic rocks, give it the key characteristics of known, mostly Proterozoic, intrusions that host world-class Ni-Cu-Co ore deposits.
Rea R.V.,University of Northern British Columbia |
Rea R.V.,3333 University Way |
Johnson C.J.,University of Northern British Columbia |
Emmons S.,University of Northern British Columbia
Journal of Fish and Wildlife Management | Year: 2014
To have a better understanding of the ecological factors that may contribute to moose Alces alces and vehicle collisions in northern British Columbia, we analyzed Wildlife Accident Reporting System data that were collected between 2000 and 2005 by highway maintenance contractors. We delineated 29 moose-vehicle collision hotspots and 15 control sites at which we assessed environmental and road infrastructure attributes through field surveys and remotely sensed data. A logistic regression model including both coarse- and fine-scale environmental factors suggested that hotspots were more likely to be characterized by the number of roadside mineral licks and bisection of the highway corridor through black spruce forest-sphagnum bog habitat and swamps. The absence of rivers within 1 km and less lake area within 500 m of the highway also better characterized hotspots than controls. At the fine scale, deciduous forest cover along the highway edge and the proportion of browse to nonbrowse vegetation between the road shoulder and forest edge were also related to collision sites. Based on these data, the mitigation of collision hotspots should include decommissioning roadside mineral licks where they occur and cutting roadside brush to improve driver visibility and reduce browse resprouting and attractiveness. Where new road construction or road realignments are being contemplated, we recommend considering routes with more lake area, more rivers, fewer swamps, and fewer black spruce forest-sphagnum bog habitats to help reduce collisions. We discuss the utility of installing novel warning signage in areas where collisions are recurrent.
Farrokhsiar M.,3333 University way |
Najjaran H.,3333 University way
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2011
An analysis of the future measurement incorporation into the unscented predictive motion planning algorithm for nonholonomic systems is presented. A two-wheeled robot is selected as the example nonholonomic system. A predictive motion planning scheme is used to find the suboptimal control inputs. In addition to the nonholonomic constraint, state estimation and collision avoidance chance constraints are incorporated to the predictive scheme. The closed form of the probabilistic constraints is solved by utilizing the unscented transform of the motion model. In order to evaluate the effect of future measurement incorporation into the planning algorithm, two different types of the unscented predictive planner, UPP-1 and UPP-2, are developed. In UPP-2 the future measurement is incorporated to the planning algorithm, whereas in UPP-1 the future measurement is ignored. Numerical simulation results demonstrate a high level of robustness and effectiveness of the both proposed algorithms in the presence of disturbances, measurement noise and chance constraints. Also, simulation results indicate that UPP-1 is a more conservative planner than UPP-2. © 2011 Springer-Verlag.
Kobylinski A.,University of Northern British Columbia |
Fredeen A.L.,University of Northern British Columbia |
Fredeen A.L.,3333 University Way
Forests | Year: 2015
The importance of N2-fixing arboreal cyanolichens to the nitrogen (N)-balance of sub-boreal interior hybrid spruce (Picea glauca × engelmannii) and subalpine fir (Abies lasiocarpa) forests was examined at field sites in central BC, Canada. Host trees were accessed by a single-rope climbing technique and foliage as well as arboreal macrolichen functional groups were sampled by branch height in eight random sample trees from each of two high (High Cyano) and two low (Low Cyano) cyanolichen abundance sites for a total of 32 sample trees. Natural abundances of stable isotopes of N (15N, 14N) and carbon (13C, 12C) were determined for aggregate host tree and epiphytic lichen samples, as well as representative samples of upper organic and soil horizons (Ae and Bf) from beneath host trees. As expected, N2-fixing cyanolichens had 2-6-fold greater N-contents than chlorolichens and a δ15N close to atmospheric N2, while foliage and chlorolichens were more depleted in 15N. By contrast, soils at all trees and sites were 15N-enriched (positive δ15N), with declining (not significant) δ15N with increased tree-level cyanolichen abundance. Lichen functional groups and tree foliage fell into three distinct groups with respect to δ13C; the tripartite cyanolichen Lobaria pulmonaria (lightest), host-tree needles (intermediate), and bipartite cyanolichens, hair (Alectoria and Bryoria spp.) and chlorolichens (heaviest). Branch height of host trees was an effective predictor of needleδ13C. Our results showed a modest positive correlation between host tree foliage N and cyanolichen abundance, supporting our initial hypothesis that higher cyanolichen abundances would elevate host tree foliar N. Further study is required to determine if high cyanolichen abundance enhances host tree and/or stand-level productivity in sub-boreal forests of central BC, Canada. © 2015 by the authors.
Park N.D.,3333 University Way |
Helle S.S.,3333 University Way |
Thring R.W.,3333 University Way
Biomass and Bioenergy | Year: 2012
Samples of pulp mill waste activated sludge were thickened by centrifugation, from approximately 25 g kg -1 TS to approximately 65 g kg -1 TS, and subjected to combined alkaline (NaOH dosage of 0.206 and 0.261 g g -1 TS respectively) and ultrasonic (39.6 and 16.8 MJ kg -1 TS, respectively) pre-treatment. Pre-treatment increased the soluble TS, VS, and COD of the pulp sludge 3-14 times over non-treated sludge. Batch anaerobic digestions were used to compare the effects of sludge pre-treatment. Pre-treatment did not significantly improve biogas production over 28 d, but did increase VS reduction (21 ± 3 to 30 ± 0.8% for the 25 g kg -1 TS sludge and 23 ± 0.5 to 27 ± 0.7% for 65 g kg -1 TS sludge). Pre-treatment increased the initial rate of methane production. 80% of the total methane production was reached 5-6 d earlier when pre-treated. Overall methane production was found to be 404 ± 205 and 222 ± 123 mL g -1 VS consumed for 25 g kg -1 TS sludge non-treated and pre-treated sludge and 384 ± 183 and 354 ± 93 mL g -1 VS consumed for 65 g kg -1 TS non-treated and pre-treated sludge. Pre-treatment reduced the dewaterability of both sludges. Thickening by centrifugation reduced the total S content of the dried sludge. Overall, biogas production from pulp sludge was unstable and inconsistent. Further research is required to determine the cause of inhibition. © 2012 Elsevier Ltd.