236 research outputs found

    Performance of Climate Projections for Yukon and Adjacent Northwest Territories, 1991 – 2020

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    Permafrost foundation design recognizes the impact of climate change on soil bearing capacity, as described in Canadian guideline CSA PLUS 4011:19. There is, however, no guidance as to the climate scenarios most prudent to adopt for such design. We have compared climate change scenarios outlined in 2003 for the design of the proposed Mackenzie Gas Project (MGP) with climate data for 1991 – 2020 to determine the projections most representative of what did, in fact, occur. In Canada, the greatest change in climate during the last 50 years has been measured in the western Arctic, where fluctuations in annual air temperatures are regionally consistent. In this region, the rate of change in annual mean air temperature for 1971 – 2020 has ranged from 0.77 °C decade-1 at Inuvik, NT, to 0.30 °C decade-1 at Komakuk Beach, YT, with warming concentrated in winter. No statistically significant trends in total annual precipitation have been observed and these records are poorly correlated within the region. In 2003, 29 climate projections from seven global climate models were examined for the MGP and, in 2005, for research regarding forest fires in Yukon. The observed climate warming in Yukon and adjacent Northwest Territories during 1991 – 2020 was close to the upper projections for mean annual and winter air temperature. For example, at Inuvik the 2.3 °C increase observed in mean annual air temperature between 1961 – 90 and 1991 – 2020, exceeds the median projection for change by 2010 – 39 of +1.6 °C and approaches the upper value of +2.4 °C. No consistency between observed and projected precipitation has been determined. These results indicate that, when required, future projections of temperature in northwest Canada may prudently adopt higher or more extreme scenarios because they have been the most realistic to date. They imply that near-surface permafrost may soon become unsustainable in southern parts of the region and so site investi gations to locate thaw-stable soils will likely be cost effective for new projects

    Experiencing Business in a Whole New World

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    My Go Global experience was something I\u27ll never forget, and quite honestly, it has been all I could talk about coming back to school. To visit top-tier businesses in other countries, visit a country’s most sacred ruin, and finish it all up with a mini internship as a micro-finance consultant, was one of the best experiences of my life. There really is no other program that can give a cultural exposure, open up your eyes to global business, and help you see what value you can add to this world than the Go Global Program.https://digitalcommons.usu.edu/huntsman_news/1199/thumbnail.jp

    Safety and immunogenicity of H1/IC31®, an adjuvanted TB subunit vaccine, in HIV-infected adults with CD4+ lymphocyte counts greater than 350 cells/mm3: a phase II, multi-centre, double-blind, randomized, placebo-controlled trial.

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    BACKGROUND: Novel tuberculosis vaccines should be safe, immunogenic, and effective in various population groups, including HIV-infected individuals. In this phase II multi-centre, double-blind, placebo-controlled trial, the safety and immunogenicity of the novel H1/IC31 vaccine, a fusion protein of Ag85B-ESAT-6 (H1) formulated with the adjuvant IC31, was evaluated in HIV-infected adults. METHODS: HIV-infected adults with CD4+ T cell counts >350/mm3 and without evidence of active tuberculosis were enrolled and followed until day 182. H1/IC31 vaccine or placebo was randomly allocated in a 5:1 ratio. The vaccine was administered intramuscularly at day 0 and 56. Safety assessment was based on medical history, clinical examinations, and blood and urine testing. Immunogenicity was determined by a short-term whole blood intracellular cytokine staining assay. RESULTS: 47 of the 48 randomised participants completed both vaccinations. In total, 459 mild or moderate and 2 severe adverse events were reported. There were three serious adverse events in two vaccinees classified as not related to the investigational product. Local injection site reactions were more common in H1/IC31 versus placebo recipients (65.0% vs. 12.5%, p = 0.015). Solicited systemic and unsolicited adverse events were similar by study arm. The baseline CD4+ T cell count and HIV viral load were similar by study arm and remained constant over time. The H1/IC31 vaccine induced a persistent Th1-immune response with predominately TNF-α and IL-2 co-expressing CD4+ T cells, as well as polyfunctional IFN-γ, TNF-α and IL-2 expressing CD4+ T cells. CONCLUSION: H1/IC31 was well tolerated and safe in HIV-infected adults with a CD4+ Lymphocyte count greater than 350 cells/mm3. The vaccine did not have an effect on CD4+ T cell count or HIV-1 viral load. H1/IC31 induced a specific and durable Th1 immune response. TRIAL REGISTRATION: Pan African Clinical Trials Registry (PACTR) PACTR201105000289276

    Genetically based low oxygen affinities of felid hemoglobins: Lack of biochemical adaptation to high-altitude hypoxia in the snow leopard

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    Genetically based modifications of hemoglobin (Hb) function that increase blood–O2 affinity are hallmarks of hypoxia adaptation in vertebrates. Among mammals, felid Hbs are unusual in that they have low intrinsic O2 affinities and reduced sensitivities to the allosteric cofactor 2,3-diphosphoglycerate (DPG). This combination of features compromises the acclimatization capacity of blood–O2 affinity and has led to the hypothesis that felids have a restricted physiological niche breadth relative to other mammals. In seeming defiance of this conjecture, the snow leopard (Panthera uncia) has an extraordinarily broad elevational distribution and occurs at elevations above 6000 m in the Himalayas. Here, we characterized structural and functional variation of big cat Hbs and investigated molecular mechanisms of Hb adaptation and allosteric regulation thatmay contribute to the extreme hypoxia tolerance of the snow leopard. Experiments revealed that purified Hbs from snow leopard and African lion exhibited equally low O2 affinities and DPG sensitivities. Both properties are primarily attributable to a single amino acid substitution, β2His→Phe, which occurred in the common ancestor of Felidae. Given the low O2 affinity and reduced regulatory capacity of feline Hbs, the extreme hypoxia tolerance of snow leopards must be attributable to compensatory modifications of other steps in the O2-transport pathway

    Distinct regulation of Ubc13 functions by the two ubiquitin-conjugating enzyme variants Mms2 and Uev1A

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    Ubc13, a ubiquitin-conjugating enzyme (Ubc), requires the presence of a Ubc variant (Uev) for polyubiquitination. Uevs, although resembling Ubc in sequence and structure, lack the active site cysteine residue and are catalytically inactive. The yeast Uev (Mms2) incites noncanonical Lys63-linked polyubiquitination by Ubc13, whereas the increased diversity of Uevs in higher eukaryotes suggests an unexpected complication in ubiquitination. In this study, we demonstrate that divergent activities of mammalian Ubc13 rely on its pairing with either of two Uevs, Uev1A or Mms2. Structurally, we demonstrate that Mms2 and Uev1A differentially modulate the length of Ubc13-mediated Lys63-linked polyubiquitin chains. Functionally, we describe that Ubc13–Mms2 is required for DNA damage repair but not nuclear factor κB (NF-κB) activation, whereas Ubc13–Uev1A is involved in NF-κB activation but not DNA repair. Our finding suggests a novel regulatory mechanism in which different Uevs direct Ubcs to diverse cellular processes through physical interaction and alternative polyubiquitination
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