6,375 research outputs found

    Amplitude Variations in Pulsating Yellow Supergiants

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    It was recently discovered that the amplitudes of pulsating red giants and supergiants vary significantly on time scales of 20-30 pulsation periods. Here, we analyze the amplitude variability in 29 pulsating yellow supergiants (5 RVa, 4 RVb, 9 SRd, 7 long-period Cepheid, and 4 yellow hypergiant stars), using visual observations from the AAVSO International Database, and Fourier and wavelet analysis using the AAVSO's VSTAR package. We find that these stars vary in amplitude by factors of up to 10 or more (but more typically 3-5), on a mean time scale (L) of 33 +/- 4 pulsation periods (P). Each of the five sub-types shows this same behavior, which is very similar to that of the pulsating red giants, for which the median L/P was 31. For the RVb stars, the lengths of the cycles of amplitude variability are the same as the long secondary periods, to within the uncertainty of each.Comment: To be submitted to JAAVS

    Microclimate Variability of Select Toronto Neighbourhoods Under Hot Summertime Conditions

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    Micrometeorological variability within cities has important implications for urban air and water quality, building energy consumption, and human health and thermal comfort. However, the monitoring of microscale climate is not routinely conducted. In most instances, primary meteorological observations are made under reproducible standard conditions (typically at an airport); but these open field observations tend to be unrepresentative of the intra-urban meteorological conditions. This thesis used an alternative approach of conducting mobile traverse measurements using vehicle-mounted sensors to characterize the microclimates of Toronto, ON under hot, summertime weather conditions. Sampling occurred along two routes and incorporated sampling 8 intra-urban neighbourhoods with contrasting surface properties. In addition, a rural reference and two areas identified by Toronto Public Health (TPH) as ‘high-risk’ in relation to human health were sampled – the Thorncliffe Park and Moss Park neighbourhoods. These observations were used to address the following: 1) What is the intra-urban meteorological variability observed by vehicle traverses under daytime and nighttime conditions? 2) Compared to the other neighbourhoods, do the Thorncliffe Park and Moss Park neighbourhoods exhibit microclimates associated with higher human thermal discomfort? 3) How does an urban-scale numerical model perform in predicting neighbourhood-scale microclimates? The results presented in this thesis demonstrate significant microscale intra-urban variability from 9 daytime and 3 nighttime traverses. Numerical model outputs show relatively good agreement with vehicle traverse observations, where ΔTair (mod-obs) \u3c -1.1 ÂșC and ΔTdew (mod-obs) \u3c -1.7 ÂșC in 8 of 11 evaluated vehicle traverses. The application of these results can provide insight to where in Toronto public health is at highest risk and where heat mitigation strategies are most needed

    Evaluating the association between extreme heat and mortality in urban Southwestern Ontario using different temperature data sources

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    Urban areas have complex thermal distribution. We examined the association between extreme temperature and mortality in urban Ontario, using two temperature data sources: high-resolution and weather station data. We used distributed lag non-linear Poisson models to examine census division-specific temperature–mortality associations between May and September 2005–2012. We used random-effect multivariate meta-analysis to pool results, adjusted for air pollution and temporal trends, and presented risks at the 99th percentile compared to minimum mortality temperature. As additional analyses, we varied knots, examined associations using different temperature metrics (humidex and minimum temperature), and explored relationships using different referent values (most frequent temperature, 75th percentile of temperature distribution). Weather stations yielded lower temperatures across study months. U-shaped associations between temperature and mortality were observed using both high-resolution and weather station data. Temperature–mortality relationships were not statistically significant; however, weather stations yielded estimates with wider confidence intervals. Similar findings were noted in additional analyses. In urban environmental health studies, high-resolution temperature data is ideal where station observations do not fully capture population exposure or where the magnitude of exposure at a local level is important. If focused upon temperature–mortality associations using time series, either source produces similar temperature–mortality relationships

    Implementing Generalized Empirical Method in Neuroscience by Functionally Ordering Tasks

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    This article outlines a method of collaboration that will manifest a high probability of cumulative and progressive results in science. The method will accomplish this through a division of labour grounded in the order of occurrence of human cognitional operations. The following article explores the possibility of a method known as functional specialization, distinct tasks presently operative in neuroscience. Functional specialization will enhance collaboration within a science as well as initiate implementation of generalized empirical method. Implementation of generalized empirical method will be achieved through the focus of individual specialties on specific mental operations

    The Eastman Kodak Co. and the Canadian Kodak Co. Ltd: Re-structuring the Canadian photographic industry, c.1885-1910

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    Within the accepted historiography of photography, the importance of George Eastman and the Eastman Kodak Company (EKC) has become unassailable. They have been placed as the key, and often sole, agent in “revolutionizing” the amateur photography market in the late nineteenth century. While the photographic landscape and market of 1885-1914 was indeed radically altered, the historiographical dominance of what can be identified as the “Kodak story” has obscured the means through which EKC’s successful re-structuring of the existing manufacturing and distribution networks of photographic materials occurred. I argue that the changes effected by Eastman and the EKC began not with imaging desires, but with their acknowledgment, and profound understanding of the existing and competing interests within the photographic industry. This thesis focuses on the EKC’s re-structuring of the extant and evolving communities involved in the manufacturing and distribution of photographic materials in Canada between 1885-1910. Focusing particularly on the period immediately surrounding the establishment of the Canadian Kodak Co. Limited in 1899, I demonstrate the re-structuring processes at work, including: market and financial diversification; governmental lobbying; purchase and mergers; and other business and marketing-based strategies. I frame my theoretical positions and analysis of network re-structuring through the experiences of Ottawa professional photographer and photographic business owner William James Topley (active 1868-1907), and CKCoLtd manager John Garrison Palmer (active 1886-1921). Topley and Garrison’s professional experiences and interactions with expanded communities of photographic consumers and industry participants provide an opportunity for specific and detailed findings which challenge understandings of the evolution of the practice of photography during this transitional period. In doing so, I provide evidence of the primary role network re-structuring played in the EKC’s ability to shape the wider international photographic industry to their advantage in the early twentieth century

    IBD genetic risk profile in healthy first-degree relatives of Crohn's disease patients

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    BACKGROUND: Family history provides important information on risk of developing inflammatory bowel disease [IBD], and genetic profiling of first-degree relatives [FDR] of Crohn's disease [CD]- affected individuals might provide additional information. We aimed to delineate the genetic contribution to the increased IBD susceptibility observed in FDR. METHODS: N = 976 Caucasian, healthy, non-related FDR; n = 4997 independent CD; and n = 5000 healthy controls [HC]; were studied. Genotyping for 158 IBD-associated single nucleotide polymorphisms [SNPs] was performed using the Illumina Immunochip. Risk allele frequency [RAF] differences between FDR and HC cohorts were correlated with those between CD and HC cohorts. CD and IBD genetic risk scores [GRS] were calculated and compared between HC, FDR, and CD cohorts. RESULTS: IBD-associated SNP RAF differences in FDR and HC cohorts were strongly correlated with those in CD and HC cohorts, correlation coefficient 0.63 (95% confidence interval [CI] 0.53 - 0.72), p = 9.90 x 10(-19). There was a significant increase in CD-GRS [mean] comparing HC, FDR, and CD cohorts: 0.0244, 0.0250, and 0.0257 respectively [p < 1.00 x 10(-7) for each comparison]. There was no significant difference in the IBD-GRS between HC and FDR cohorts [p = 0.81]; however, IBD-GRS was significantly higher in CD compared with FDR and HC cohorts [p < 1.00 x 10(-10) for each comparison]. CONCLUSION: FDR of CD-affected individuals are enriched with IBD risk alleles compared with HC. Cumulative CD-specific genetic risk is increased in FDR compared with HC. Prospective studies are required to determine if genotyping would facilitate better risk stratification of FDR
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