1722 research outputs found
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Avoidability index for binary patterns with reversal
Get PDFFor every pattern p over the alphabet {x, x^R, y, y^R}, we specify the least k such that p is k-avoidable.The first author was supported by an NSERC Discovery Grant, and also by Deutsche Forschungsge-meinschaft, which supported him through its Mercator program. The second author was supported through the NSERC USRA program.http://www.combinatorics.org/ojs/index.php/eljc/article/view/v23i1p3
Detection of rotational spectral variation on the M-type asteroid (16) Psyche
Get PDFThe asteroid (16) Psyche is of scientific interest because it contains ∼1% of the total mass of the asteroid belt and is thought to be the remnant metallic core of a protoplanet. Radar observations have indicated the significant presence of metal on the surface with a small percentage of silicates. Prior ground-based observations showed rotational variations in the near-infrared (NIR) spectra and radar albedo of this asteroid. However, no comprehensive study that combines multi-wavelength data has been conducted so far. Here we present rotationally resolved NIR spectra (0.7–2.5 μm) of (16) Psyche obtained with the NASA Infrared Telescope Facility. These data have been combined with shape models of the asteroid for each rotation phase. Spectral band parameters extracted from the NIR spectra show that the pyroxene band center varies from ∼0.92 to 0.94 μm. Band center values were used to calculate the pyroxene chemistry of the asteroid, whose average value was found to be Fs30En65Wo5. Variations in the band depth (BD) were also observed, with values ranging from 1.0% to 1.5%. Using a new laboratory spectral
calibration method, we estimated an average orthopyroxene content of 6% ± 1%. The mass-deficit region of Psyche, which exhibits the highest radar albedo, also shows the highest value for the spectral slope and the minimum BD. The spectral characteristics of Psyche suggest that its parent body did not have the typical structure expected for a differentiated body or that the sequence of events that led to its current state was more complex than previously thought.This research work was supported by NASA Planetary Mission Data Analysis Program Grant NNX13AP27G, NASA NEOO Program Grant NNX12AG12G, and NASA Planetary
Geology and Geophysics Program Grant NNX11AN84G… The Arecibo Planetary Radar Program is supported by the National Aeronautics and Space Administration under Grant Nos. NNX12AF24G and NNX13AQ46G, issued through the Near Earth Object Observations program. E.A.C. thanks the Canada Foundation for Innovation, the Manitoba Research Innovations Fund, the Canadian Space Agency, the Natural Sciences and Engineering Research Council of Canada, and the University of Winnipeg for supporting the establishment and ongoing operation of the University of Winnipeg’s Planetary Spectrophotometer Facility.http://iopscience.iop.org/article/10.3847/1538-3881/153/1/29/met
Who’s Doing What About Poverty Reduction
Get PDFhttps://www.policyalternatives.ca/publications/commentary/unspun-whos-doing-what-about-poverty-reductio
Surface albedo and spectral variability of Ceres
Get PDFPrevious observations suggested that Ceres has active, but possibly sporadic, water outgassing as well as possibly varying spectral characteristics over a timescale of months. We used all available data of Ceres collected in the past three decades from the ground and the Hubble Space Telescope, as well as the newly acquired images by the Dawn Framing Camera, to search for spectral and albedo variability on Ceres, on both a global scale and in local regions, particularly the bright spots inside the Occator crater, over timescales of a few months to decades. Our analysis has placed an upper limit on the possible temporal albedo variation on Ceres. Sporadic water vapor venting, or any possibly ongoing activity on Ceres, is not significant enough to change the albedo or the area of the bright features in the Occator crater by >15%, or the global albedo by >3% over the various timescales that we searched. Recently reported spectral slope variations can be explained by changing Sun–Ceres–Earth geometry. The active area on Ceres is less than 1 km2, too small to cause global albedo and spectral variations detectable in our data. Impact ejecta due to impacting projectiles of tens of meters in size like those known to cause observable changes to the surface albedo on Asteroid Scheila cannot cause detectable albedo change on Ceres due to its relatively large size and strong gravity. The water vapor activity on Ceres is independent of Ceres’ heliocentric distance, ruling out the possibility of the comet-like sublimation process as a possible mechanism driving the activity.The Framing Camera project is financially supported by the Max Planck Society and the German Space Agency, DLR. Li is supported by a subcontract from the University of
California, Los Angeles under the NASA Contract #NNM05AA86 Dawn Discovery Mission.http://iopscience.iop.org/article/10.3847/2041-8205/817/2/L22/met
Briefing Note: Community Forestry in Canada
Get PDFGlobal economic instability, the need for local adaptation to climate change impacts, and Supreme Court rulings over Aboriginal and Treaty Rights have drawn attention to community dissatisfaction with centralized approaches to natural resource management. Communities across Canada seek opportunities for increased control over and benefits from natural resources
Snow covered soils produce N₂O that is lost from forested catchments prior to snowmelt
No full textThe magnitude of net soil nitrous oxide (N₂O) production from a snow‐covered catchment in a northern temperate forest was investigated. There was considerable net soil N₂O‐N production and consumption through the snowpack, ranging from −6.6 to 26.2 g‐N ha⁻¹ d⁻¹. There was no difference in net N₂O production among topographic positions despite significant variation in soil moisture, reduction‐oxidation conditions, and pore water dissolved organic carbon and nitrate. Soil temperatures did not vary among topographic positions, suggesting that temperatures at or above the freezing point allow N₂O production to proceed under the snowpack. Redox conditions were lower at wetland positions compared to lowlands and uplands, suggesting that the biogeochemical pathway of N₂O production varies with topography. Over the entire nongrowing season, 1.5 kg of N₂O‐N was exported to the atmosphere from the 6.33 ha catchment, representing 31% of the growing season N₂O‐N production. These results suggest that winter is an active time for gaseous N production in these forests and that N₂O production under the snowpack represents an often unmonitored flux of N from catchments."This research was funded by an NSERC Discovery grant to I.F. Creed (217053-2009 RGPIN)."https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JG00341
Where's Downtown? Varying Geographic Definitions of Winnipeg's Downtown and Inner City, 1947-2004
Get PDF19 pages: illustrations, maps; digital file.This series of maps was created to provide a basic overview of how downtown Winnipeg has been defined over time and by different organizations. These definitions of downtown were downloaded from the Manitoba Land Initiative and Open Data Winnipeg websites, given to us by members of the Winnipeg Data Consortium, or redrawn from maps in the Institute of Urban Studies Library and the Manitoba Historical Maps flickr page
Prolegomena To An Anglican Discussion of Authority: The Role of History on The Current Crisis
Get PDFAuthority is problematic. It is problematic in theory, and it is problematic in practice. According to the Lutheran theologian Günther Gassmann, "The issue of authority has been a perennial problem in the framework of Christian thinking, Christian life, and the church." This general problem of Christian authority has at the present moment taken on unique features within the Anglican Communion, where today it threatens it with schism. Through this thesis I will investigate the history of the Anglican church around the question of authority and how this has lead the Communion to its current crisis on the subject. The overreaching argument of this thesis will be two-fold. First, that Anglicanism has historically never had an uncontested practice, or doctrine, of authority up to the present day. Second, that, because of this, the history of Anglicanism needs to play a much larger role in the current discussions around the crisis of authority as there is much to learn from it. There is no simple solution to the challenges that face the Communion, and none is put forward here. What this thesis seeks to do is offer up a modest starting point from which further discussions on the concept and practice of authority within Anglicanism can move forward from.Master of Arts in Theological Studie
Estimating the Economic Cost of Obesity in Canadian Populations
Get PDFThis study aims to provide a more complete description of who suffers most severely from obesity in terms of both the prevalence of the disease and its associated costs. Literature estimating the cost of obesity is often highly aggregated and combines data on all age groups, genders, and ethnicities. I disaggregate across relevant variables to identify the most troublesome obese populations in Canada in terms of economic cost. The second goal of my research is to consider how these specific Canadian populations (age groups, genders, and ethnicities) are expected to grow to gain a more accurate prediction of how the total economic cost of obesity will change in the near future and whether those costs should be deemed an epidemic for our economy
Energetic benefits of enhanced summer roosting habitat for little brown bats (Myotis lucifugus) recovering from white-nose syndrome
Get PDFHabitat modification can improve outcomes for imperilled wildlife. Insectivorous bats in North America face a range of conservation threats, including habitat loss and white-nose syndrome (WNS). Even healthy bats face energetic constraints during spring, but enhancement of roosting habitat could reduce energetic costs, increase survival and enhance recovery from WNS. We tested the potential of artificial heating of bat roosts as a management tool for threatened bat populations. We predicted that: (i) after hibernation, captive bats would be more likely to select a roost maintained at a temperature near their thermoneutral zone; (ii) bats recovering from WNS at the end of hibernation would show a stronger preference for heated roosts compared with healthy bats; and (iii) heated roosts would result in biologically significant energy savings. We housed two groups of bats (WNS-positive and control) in separate flight cages following hibernation. Over 7.5 weeks, we quantified the presence of individuals in heated vs. unheated bat houses within each cage. We then used a series of bioenergetic models to quantify thermoregulatory costs in each type of roost under a number of scenarios. Bats preferentially selected heated bat houses, but WNS-affected bats were much more likely to use the heated bat house compared with control animals. Our model predicted energy savings of up to 81.2% for bats in artificially heated roosts if roost temperature was allowed to cool at night to facilitate short bouts of torpor. Our results are consistent with research highlighting the importance of roost microclimate and suggest that protection and enhancement of high-quality, natural roosting environments should be a priority response to a range of threats, including WNS. Our findings also suggest the potential of artificially heated bat houses to help populations recover from WNS, but more work is needed before these might be implemented on a large scale.This work was supported by scholarships from the Natural Sciences and Engineering Research Council (NSERC, Canada) and University of Winnipeg Graduate Studies to A.W. and grants from the US Fish and Wildlife Service, Bat Conservation International and NSERC to C.K.R.W.https://academic.oup.com/conphys/article/4/1/cov070/295131