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22 Research products, page 1 of 3

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  • 2012-2021
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  • Open Access English
    Authors: 
    Borges do Nascimento, Israel Júnior et al.;

    A growing body of literature on the 2019 novel coronavirus (SARS-CoV-2) is becoming available, but a synthesis of available data has not been conducted. We performed a scoping review of currently available clinical, epidemiological, laboratory, and chest imaging data related to the SARS-CoV-2 infection. We searched MEDLINE, Cochrane CENTRAL, EMBASE, Scopus and LILACS from 01 January 2019 to 24 February 2020. Study selection, data extraction and risk of bias assessment were performed by two independent reviewers. Qualitative synthesis and meta-analysis were conducted using the clinical and laboratory data, and random-e ects models were applied to estimate pooled results. A total of 61 studies were included (59,254 patients). The most common disease-related symptoms were fever (82%, 95% confidence interval (CI) 56%–99%; n = 4410), cough (61%, 95% CI 39%–81%; n = 3985), muscle aches and/or fatigue (36%, 95% CI 18%–55%; n = 3778), dyspnea (26%, 95% CI 12%–41%; n = 3700), headache in 12% (95% CI 4%–23%, n = 3598 patients), sore throat in 10% (95% CI 5%–17%, n = 1387) and gastrointestinal symptoms in 9% (95% CI 3%–17%, n=1744). Laboratory findings were described in a lower number of patients and revealed lymphopenia (0.93 109/L, 95% CI 0.83–1.03 109/L, n = 464) and abnormal C-reactive protein (33.72 mg/dL, 95% CI 21.54–45.91 mg/dL; n = 1637). Radiological findings varied, but mostly described ground-glass opacities and consolidation. Data on treatment options were limited. All-cause mortality was 0.3% (95% CI 0.0%–1.0%; n = 53,631). Epidemiological studies showed that mortality was higher in males and elderly patients. The majority of reported clinical symptoms and laboratory findings related to SARS-CoV-2 infection are non-specific. Clinical suspicion, accompanied by a relevant epidemiological history, should be followed by early imaging and virological assay.

  • Other research product . 2014
    Open Access English
    Authors: 
    Xin Jiang, Albert; Soriano Marcolino, Leandro; Procaccia, Ariel D.; Sandholm, Tuomas; Shah, Nisarg; Tambe, Milind;
    Country: United Kingdom
    Project: NSF | CAREER: A Broad Synthesis... (1350598), NSF | ICES: Small: Computationa... (1215883)

    We investigate the power of voting among diverse, randomized software agents. With teams of computer Go agents in mind, we develop a novel theoretical model of two-stage noisy voting that builds on recent work in machine learning. This model allows us to reason about a collection of agents with different biases (determined by the first-stage noise models), which, furthermore, apply randomized algorithms to evaluate alternatives and produce votes (captured by the second-stage noise models). We analytically demonstrate that a uniform team, consisting of multiple instances of any single agent, must make a significant number of mistakes, whereas a diverse team converges to perfection as the number of agents grows. Our experiments, which pit teams of computer Go agents against strong agents, provide evidence for the effectiveness of voting when agents are diverse.

  • Open Access English
    Authors: 
    Fletcher, Tamara L.; Warden, Lisa; Sinninghe Damsté, Jaap S.; Brown, Kendrick J.; Rybczynski, Natalia; Gosse, John C.; Ballantyne, Ashley P.;
    Project: NSERC , EC | PACEMAKER (226600), NSF | Collaborative Research: A... (1418421), NWO | Perturbations of System E... (11030)

    The mid-Pliocene is a valuable time interval for investigating equilibrium climate at current atmospheric CO2 concentrations because atmospheric CO2 concentrations are thought to have been comparable to the current day and yet the climate and distribution of ecosystems were quite different. One intriguing, but not fully understood, feature of the early to mid-Pliocene climate is the amplified Arctic temperature response and its impact on Arctic ecosystems. Only the most recent models appear to correctly estimate the degree of warming in the Pliocene Arctic and validation of the currently proposed feedbacks is limited by scarce terrestrial records of climate and environment. Here we reconstruct the summer temperature and fire regime from a subfossil fen-peat deposit on west–central Ellesmere Island, Canada, that has been chronologically constrained using cosmogenic nuclide burial dating to 3.9+1.5/-0.5 Ma. The estimate for average mean summer temperature is 15.4±0.8 ∘C using specific bacterial membrane lipids, i.e., branched glycerol dialkyl glycerol tetraethers. This is above the proposed threshold that predicts a substantial increase in wildfire in the modern high latitudes. Macro-charcoal was present in all samples from this Pliocene section with notably higher charcoal concentration in the upper part of the sequence. This change in charcoal was synchronous with a change in vegetation that included an increase in abundance of fire-promoting Pinus and Picea. Paleo-vegetation reconstructions are consistent with warm summer temperatures, relatively low summer precipitation and an incidence of fire comparable to fire-adapted boreal forests of North America and central Siberia. To our knowledge, this site provides the northernmost evidence of fire during the Pliocene. It suggests that ecosystem productivity was greater than in the present day, providing fuel for wildfires, and that the climate was conducive to the ignition of fire during this period. The results reveal that interactions between paleo-vegetation and paleoclimate were mediated by fire in the High Arctic during the Pliocene, even though CO2 concentrations were similar to modern values.

  • Open Access English
    Authors: 
    Wang, Yingshuo; Ren, Jing;
    Country: Canada

    The purpose of the paper is to investigate the rebalancing strategy for Simon Fraser University’s Academic Pension Plan’s Balanced Fund. First, we examine performances of a “no rebalancing” fund and rebalanced funds with different rebalancing frequencies and thresholds based on the historic data. The results show that the rebalancing frequency and thresholds do not significantly affect the performance of the portfolio. Additionally, the rebalanced portfolios significantly outperform the “no rebalancing” portfolio. More important, we examine whether the conclusion from one historic simulation holds in 10,000 Monte Carlo simulations based on historic means, variances and co-variances and two sets of hypothetical means. The results indicate that the higher rebalancing frequency and smaller threshold will reduce cumulative wealth of rebalanced portfolios and reduce risk.

  • Open Access
    Authors: 
    Yang, Yuanyu;
    Country: Canada
    Project: CIHR

    Juvenile Idiopathic Arthritis (JIA) is the most common rheumatic disease of childhood. Our objective is to predict the results of remission so that those children who are likely to experience poor remission outcomes could benefit from early aggressive treatment. Many classification techniques could provide either a binary prediction or an estimated probability of remission. However, parents would like to know more specifically about the remission outcomes of children similar to their own. In this project, we propose a supervised clustering method that provides this information. Inspired by the basic idea of supervised principal component analysis, we perform supervision by selecting and/or weighting explanatory variables differently depending on their associations with the class response. Our supervised clustering method is applied to JIA data and to data simulated with known properties. Our method is shown to be competitive with an existing supervised clustering method, classification trees and random forests in terms of out-of-sample misclassification rates.

  • Open Access English
    Authors: 
    Shi, Qiong; Wang, Jun;
    Country: Canada

    This paper examines the relationship between banks lending and monetary policy for banks with different level of capital ratio. We study the relation using the sample of U.S. banks over the period 1994 to 2010. We choose short term interest rate, deposit, security and GDP as components of monetary policy. We use bank loan change as the dependent variable, short term interest rate, deposit, security, GDP change and 1 year lagged change as independent variables for the regression model. Our model returns significant results for all independent variables except security change lagged variable for all three categories and short term interest rate variable for best-capitalized banks. Out finding shows that the monetary policy change will significantly affect bank lending change with strongest effect on least-capitalized banks and weakest effect on best-capitalized banks.

  • Open Access English
    Authors: 
    Liang, Yuxuan; Wu, Chenyue;
    Country: Canada

    Although Capital Asset Pricing Model (CAPM), one-factor model, has strong theoretical basis and is easy to use and understand, analysts also consider other alternative models, such as Three Factor Pricing Model (TFPM) developed by Fama and French (1993). Because some differences between actual return and estimated return could be explained by the effect of capital size and book-to-market ratio. The objective of using these two similar but complementary models is to estimate the cost of equity for the US banking sector. In order to do the estimation, we would conduct the estimation of parameters for both individual bank and the whole banking sector.

  • Open Access
    Authors: 
    Zhong, Yi;
    Country: Canada

    When the solution of a partial differential equation (PDE) is analytic in a regular computational domain, spectral methods are known to yield spectral convergence. However, standard spectral methods have great difficulties in handling a complex irregular computational domain $Omega$ with boundary $partialOmega$.In the spectral domain embedding method, the irregular physical domain $Omega$ is embedded into a rectangular computational domain $R$. This allows the application of spectral methods in the extended domain $R$ provided that the coefficient and the source terms can be extended smoothly from $Omega$ to $R$.The rectangular domain $R$ is discretized with Chebyshev or Legendre collocation methods. Robin (mixed) boundary conditions on $partialOmega$ are enforced by a chosen set of control nodes distributed along $partialOmega$ in some fashion. The solution of the PDE at these control nodes satisfies the given boundary conditions forming a set of complementary constraint equations. Together with the solving operator, they form a global system of linear equations.

  • Open Access English
    Authors: 
    Park, Jung Hyun; Zhang, Lei;
    Country: Canada

    Both macroeconomic and bank-specific factors are correlated to the occurrence of Non-Performing Loans (NPL). We use a sample of U.S. banks over two distinct time periods to provide empirical evidence of various key macroeconomic and bankspecific determinants’ effects on NPLs.

  • Open Access English
    Authors: 
    Pullinen, Iida; Schmitt, Sebastian; Kang, Sungah; Sarrafzadeh, Mehrnaz; Schlag, Patrick; Andres, Stefanie; Kleist, Einhard; Mentel, Thomas F.; Rohrer, Franz; Springer, Monika; +6 more
    Project: EC | PIMMS (287382)

    The formation of organic nitrates (ONs) in the gas phase and their impact on mass formation of secondary organic aerosol (SOA) was investigated in a laboratory study for α-pinene and β-pinene photooxidation. Focus was the elucidation of those mechanisms that cause the often observed suppression of SOA mass formation by NOx, and therein the role of highly oxygenated multifunctional molecules (HOMs). We observed that with increasing NOx concentration (a) the portion of HOM organic nitrates (HOM-ONs) increased, (b) the fraction of accretion products (HOM-ACCs) decreased, and (c) HOM-ACCs contained on average smaller carbon numbers. Specifically, we investigated HOM organic nitrates (HOM-ONs), arising from the termination reactions of HOM peroxy radicals with NOx, and HOM permutation products (HOM-PPs), such as ketones, alcohols, or hydroperoxides, formed by other termination reactions. Effective uptake coefficients γeff of HOMs on particles were determined. HOMs with more than six O atoms efficiently condensed on particles (γeff>0.5 on average), and for HOMs containing more than eight O atoms, every collision led to loss. There was no systematic difference in γeff for HOM-ONs and HOM-PPs arising from the same HOM peroxy radicals. This similarity is attributed to the multifunctional character of the HOMs: as functional groups in HOMs arising from the same precursor HOM peroxy radical are identical, vapor pressures should not strongly depend on the character of the final termination group. As a consequence, the suppressing effect of NOx on SOA formation cannot be simply explained by replacement of terminal functional groups by organic nitrate groups. According to their γeff all HOM-ONs with more than six O atoms will contribute to organic bound nitrate (OrgNO3) in the particulate phase. However, the fraction of OrgNO3 stored in condensable HOMs with molecular masses > 230 Da appeared to be substantially higher than the fraction of particulate OrgNO3 observed by aerosol mass spectrometry. This result suggests losses of OrgNO3 for organic nitrates in particles, probably due to hydrolysis of OrgNO3 that releases HNO3 into the gas phase but leaves behind the organic rest in the particulate phase. However, the loss of HNO3 alone could not explain the observed suppressing effect of NOx on particle mass formation from α-pinene and β-pinene. Instead we can attribute most of the reduction in SOA mass yields with increasing NOx to the significant suppression of gas phase HOM-ACCs, which have high molecular mass and are potentially important for SOA mass formation at low-NOx conditions.

Advanced search in
Research products
arrow_drop_down
Searching FieldsTerms
Any field
arrow_drop_down
includes
arrow_drop_down
Include:
The following results are related to Canada. Are you interested to view more results? Visit OpenAIRE - Explore.
22 Research products, page 1 of 3
  • Open Access English
    Authors: 
    Borges do Nascimento, Israel Júnior et al.;

    A growing body of literature on the 2019 novel coronavirus (SARS-CoV-2) is becoming available, but a synthesis of available data has not been conducted. We performed a scoping review of currently available clinical, epidemiological, laboratory, and chest imaging data related to the SARS-CoV-2 infection. We searched MEDLINE, Cochrane CENTRAL, EMBASE, Scopus and LILACS from 01 January 2019 to 24 February 2020. Study selection, data extraction and risk of bias assessment were performed by two independent reviewers. Qualitative synthesis and meta-analysis were conducted using the clinical and laboratory data, and random-e ects models were applied to estimate pooled results. A total of 61 studies were included (59,254 patients). The most common disease-related symptoms were fever (82%, 95% confidence interval (CI) 56%–99%; n = 4410), cough (61%, 95% CI 39%–81%; n = 3985), muscle aches and/or fatigue (36%, 95% CI 18%–55%; n = 3778), dyspnea (26%, 95% CI 12%–41%; n = 3700), headache in 12% (95% CI 4%–23%, n = 3598 patients), sore throat in 10% (95% CI 5%–17%, n = 1387) and gastrointestinal symptoms in 9% (95% CI 3%–17%, n=1744). Laboratory findings were described in a lower number of patients and revealed lymphopenia (0.93 109/L, 95% CI 0.83–1.03 109/L, n = 464) and abnormal C-reactive protein (33.72 mg/dL, 95% CI 21.54–45.91 mg/dL; n = 1637). Radiological findings varied, but mostly described ground-glass opacities and consolidation. Data on treatment options were limited. All-cause mortality was 0.3% (95% CI 0.0%–1.0%; n = 53,631). Epidemiological studies showed that mortality was higher in males and elderly patients. The majority of reported clinical symptoms and laboratory findings related to SARS-CoV-2 infection are non-specific. Clinical suspicion, accompanied by a relevant epidemiological history, should be followed by early imaging and virological assay.

  • Other research product . 2014
    Open Access English
    Authors: 
    Xin Jiang, Albert; Soriano Marcolino, Leandro; Procaccia, Ariel D.; Sandholm, Tuomas; Shah, Nisarg; Tambe, Milind;
    Country: United Kingdom
    Project: NSF | CAREER: A Broad Synthesis... (1350598), NSF | ICES: Small: Computationa... (1215883)

    We investigate the power of voting among diverse, randomized software agents. With teams of computer Go agents in mind, we develop a novel theoretical model of two-stage noisy voting that builds on recent work in machine learning. This model allows us to reason about a collection of agents with different biases (determined by the first-stage noise models), which, furthermore, apply randomized algorithms to evaluate alternatives and produce votes (captured by the second-stage noise models). We analytically demonstrate that a uniform team, consisting of multiple instances of any single agent, must make a significant number of mistakes, whereas a diverse team converges to perfection as the number of agents grows. Our experiments, which pit teams of computer Go agents against strong agents, provide evidence for the effectiveness of voting when agents are diverse.

  • Open Access English
    Authors: 
    Fletcher, Tamara L.; Warden, Lisa; Sinninghe Damsté, Jaap S.; Brown, Kendrick J.; Rybczynski, Natalia; Gosse, John C.; Ballantyne, Ashley P.;
    Project: NSERC , EC | PACEMAKER (226600), NSF | Collaborative Research: A... (1418421), NWO | Perturbations of System E... (11030)

    The mid-Pliocene is a valuable time interval for investigating equilibrium climate at current atmospheric CO2 concentrations because atmospheric CO2 concentrations are thought to have been comparable to the current day and yet the climate and distribution of ecosystems were quite different. One intriguing, but not fully understood, feature of the early to mid-Pliocene climate is the amplified Arctic temperature response and its impact on Arctic ecosystems. Only the most recent models appear to correctly estimate the degree of warming in the Pliocene Arctic and validation of the currently proposed feedbacks is limited by scarce terrestrial records of climate and environment. Here we reconstruct the summer temperature and fire regime from a subfossil fen-peat deposit on west–central Ellesmere Island, Canada, that has been chronologically constrained using cosmogenic nuclide burial dating to 3.9+1.5/-0.5 Ma. The estimate for average mean summer temperature is 15.4±0.8 ∘C using specific bacterial membrane lipids, i.e., branched glycerol dialkyl glycerol tetraethers. This is above the proposed threshold that predicts a substantial increase in wildfire in the modern high latitudes. Macro-charcoal was present in all samples from this Pliocene section with notably higher charcoal concentration in the upper part of the sequence. This change in charcoal was synchronous with a change in vegetation that included an increase in abundance of fire-promoting Pinus and Picea. Paleo-vegetation reconstructions are consistent with warm summer temperatures, relatively low summer precipitation and an incidence of fire comparable to fire-adapted boreal forests of North America and central Siberia. To our knowledge, this site provides the northernmost evidence of fire during the Pliocene. It suggests that ecosystem productivity was greater than in the present day, providing fuel for wildfires, and that the climate was conducive to the ignition of fire during this period. The results reveal that interactions between paleo-vegetation and paleoclimate were mediated by fire in the High Arctic during the Pliocene, even though CO2 concentrations were similar to modern values.

  • Open Access English
    Authors: 
    Wang, Yingshuo; Ren, Jing;
    Country: Canada

    The purpose of the paper is to investigate the rebalancing strategy for Simon Fraser University’s Academic Pension Plan’s Balanced Fund. First, we examine performances of a “no rebalancing” fund and rebalanced funds with different rebalancing frequencies and thresholds based on the historic data. The results show that the rebalancing frequency and thresholds do not significantly affect the performance of the portfolio. Additionally, the rebalanced portfolios significantly outperform the “no rebalancing” portfolio. More important, we examine whether the conclusion from one historic simulation holds in 10,000 Monte Carlo simulations based on historic means, variances and co-variances and two sets of hypothetical means. The results indicate that the higher rebalancing frequency and smaller threshold will reduce cumulative wealth of rebalanced portfolios and reduce risk.

  • Open Access
    Authors: 
    Yang, Yuanyu;
    Country: Canada
    Project: CIHR

    Juvenile Idiopathic Arthritis (JIA) is the most common rheumatic disease of childhood. Our objective is to predict the results of remission so that those children who are likely to experience poor remission outcomes could benefit from early aggressive treatment. Many classification techniques could provide either a binary prediction or an estimated probability of remission. However, parents would like to know more specifically about the remission outcomes of children similar to their own. In this project, we propose a supervised clustering method that provides this information. Inspired by the basic idea of supervised principal component analysis, we perform supervision by selecting and/or weighting explanatory variables differently depending on their associations with the class response. Our supervised clustering method is applied to JIA data and to data simulated with known properties. Our method is shown to be competitive with an existing supervised clustering method, classification trees and random forests in terms of out-of-sample misclassification rates.

  • Open Access English
    Authors: 
    Shi, Qiong; Wang, Jun;
    Country: Canada

    This paper examines the relationship between banks lending and monetary policy for banks with different level of capital ratio. We study the relation using the sample of U.S. banks over the period 1994 to 2010. We choose short term interest rate, deposit, security and GDP as components of monetary policy. We use bank loan change as the dependent variable, short term interest rate, deposit, security, GDP change and 1 year lagged change as independent variables for the regression model. Our model returns significant results for all independent variables except security change lagged variable for all three categories and short term interest rate variable for best-capitalized banks. Out finding shows that the monetary policy change will significantly affect bank lending change with strongest effect on least-capitalized banks and weakest effect on best-capitalized banks.

  • Open Access English
    Authors: 
    Liang, Yuxuan; Wu, Chenyue;
    Country: Canada

    Although Capital Asset Pricing Model (CAPM), one-factor model, has strong theoretical basis and is easy to use and understand, analysts also consider other alternative models, such as Three Factor Pricing Model (TFPM) developed by Fama and French (1993). Because some differences between actual return and estimated return could be explained by the effect of capital size and book-to-market ratio. The objective of using these two similar but complementary models is to estimate the cost of equity for the US banking sector. In order to do the estimation, we would conduct the estimation of parameters for both individual bank and the whole banking sector.

  • Open Access
    Authors: 
    Zhong, Yi;
    Country: Canada

    When the solution of a partial differential equation (PDE) is analytic in a regular computational domain, spectral methods are known to yield spectral convergence. However, standard spectral methods have great difficulties in handling a complex irregular computational domain $Omega$ with boundary $partialOmega$.In the spectral domain embedding method, the irregular physical domain $Omega$ is embedded into a rectangular computational domain $R$. This allows the application of spectral methods in the extended domain $R$ provided that the coefficient and the source terms can be extended smoothly from $Omega$ to $R$.The rectangular domain $R$ is discretized with Chebyshev or Legendre collocation methods. Robin (mixed) boundary conditions on $partialOmega$ are enforced by a chosen set of control nodes distributed along $partialOmega$ in some fashion. The solution of the PDE at these control nodes satisfies the given boundary conditions forming a set of complementary constraint equations. Together with the solving operator, they form a global system of linear equations.

  • Open Access English
    Authors: 
    Park, Jung Hyun; Zhang, Lei;
    Country: Canada

    Both macroeconomic and bank-specific factors are correlated to the occurrence of Non-Performing Loans (NPL). We use a sample of U.S. banks over two distinct time periods to provide empirical evidence of various key macroeconomic and bankspecific determinants’ effects on NPLs.

  • Open Access English
    Authors: 
    Pullinen, Iida; Schmitt, Sebastian; Kang, Sungah; Sarrafzadeh, Mehrnaz; Schlag, Patrick; Andres, Stefanie; Kleist, Einhard; Mentel, Thomas F.; Rohrer, Franz; Springer, Monika; +6 more
    Project: EC | PIMMS (287382)

    The formation of organic nitrates (ONs) in the gas phase and their impact on mass formation of secondary organic aerosol (SOA) was investigated in a laboratory study for α-pinene and β-pinene photooxidation. Focus was the elucidation of those mechanisms that cause the often observed suppression of SOA mass formation by NOx, and therein the role of highly oxygenated multifunctional molecules (HOMs). We observed that with increasing NOx concentration (a) the portion of HOM organic nitrates (HOM-ONs) increased, (b) the fraction of accretion products (HOM-ACCs) decreased, and (c) HOM-ACCs contained on average smaller carbon numbers. Specifically, we investigated HOM organic nitrates (HOM-ONs), arising from the termination reactions of HOM peroxy radicals with NOx, and HOM permutation products (HOM-PPs), such as ketones, alcohols, or hydroperoxides, formed by other termination reactions. Effective uptake coefficients γeff of HOMs on particles were determined. HOMs with more than six O atoms efficiently condensed on particles (γeff>0.5 on average), and for HOMs containing more than eight O atoms, every collision led to loss. There was no systematic difference in γeff for HOM-ONs and HOM-PPs arising from the same HOM peroxy radicals. This similarity is attributed to the multifunctional character of the HOMs: as functional groups in HOMs arising from the same precursor HOM peroxy radical are identical, vapor pressures should not strongly depend on the character of the final termination group. As a consequence, the suppressing effect of NOx on SOA formation cannot be simply explained by replacement of terminal functional groups by organic nitrate groups. According to their γeff all HOM-ONs with more than six O atoms will contribute to organic bound nitrate (OrgNO3) in the particulate phase. However, the fraction of OrgNO3 stored in condensable HOMs with molecular masses > 230 Da appeared to be substantially higher than the fraction of particulate OrgNO3 observed by aerosol mass spectrometry. This result suggests losses of OrgNO3 for organic nitrates in particles, probably due to hydrolysis of OrgNO3 that releases HNO3 into the gas phase but leaves behind the organic rest in the particulate phase. However, the loss of HNO3 alone could not explain the observed suppressing effect of NOx on particle mass formation from α-pinene and β-pinene. Instead we can attribute most of the reduction in SOA mass yields with increasing NOx to the significant suppression of gas phase HOM-ACCs, which have high molecular mass and are potentially important for SOA mass formation at low-NOx conditions.