The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform
Lee Ingle - One of the best experts on this subject based on the ideXlab platform.
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Does exercise prescription based on estimated heart rate training zones exceed the ventilatory anaerobic threshold in patients with coronary heart disease undergoing usual-care cardiovascular rehabilitation? A United Kingdom perspective.
European journal of preventive cardiology, 2019Co-Authors: Sean Pymer, Simon Nichols, Jonathon Prosser, Stefan Birkett, Sean Carroll, Lee IngleAbstract:In the United Kingdom (UK), exercise intensity is prescribed from a fixed percentage range (% heart rate reserve (%HRR)) in cardiac rehabilitation programmes. We aimed to determine the accuracy of this approach by comparing it with an objective, threshold-based approach incorporating the accurate determination of ventilatory anaerobic threshold (VAT). We also aimed to investigate the role of baseline cardiorespiratory fitness status and exercise testing mode Dependency (Cycle vs. treadmill ergometer) on these relationships. A maximal cardiopulmonary exercise test was conducted on a Cycle ergometer or a treadmill before and following usual-care circuit training from two separate cardiac rehabilitation programmes from a single region in the UK. The heart rate corresponding to VAT was compared with current heart rate-based exercise prescription guidelines. We included 112 referred patients (61 years (59-63); body mass index 29 kg·m-2 (29-30); 88% male). There was a significant but relatively weak correlation (r = 0.32; p = 0.001) between measured and predicted %HRR, and values were significantly different from each other (p = 0.005). Within this cohort, we found that 55% of patients had their VAT identified outside of the 40-70% predicted HRR exercise training zone. In the majority of participants (45%), the VAT occurred at an exercise intensity <40% HRR. Moreover, 57% of patients with low levels of cardiorespiratory fitness achieved VAT at <40% HRR, whereas 30% of patients with higher fitness achieved their VAT at >70% HRR. VAT was significantly higher on the treadmill than the Cycle ergometer (p < 0.001). In the UK, current guidelines for prescribing exercise intensity are based on a fixed percentage range. Our findings indicate that this approach may be inaccurate in a large proportion of patients undertaking cardiac rehabilitation.
Agathe Pernoud - One of the best experts on this subject based on the ideXlab platform.
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Credit Freezes, Equilibrium Multiplicity, and Optimal Bailouts in Financial Networks.
2020Co-Authors: Matthew O. Jackson, Agathe PernoudAbstract:We analyze how interdependencies between organizations in financial networks can lead to multiple possible equilibrium outcomes. A multiplicity arises if and only if there exists a certain type of Dependency Cycle in the network that allows for self-fulfilling chains of defaults. We provide necessary and sufficient conditions for banks' solvency in any equilibrium. Building on these conditions, we characterize the minimum bailout payments needed to ensure systemic solvency, as well as how solvency can be ensured by guaranteeing a specific set of debt payments. Bailout injections needed to eliminate self-fulfilling Cycles of defaults (credit freezes) are fully recoverable, while those needed to prevent cascading defaults outside of Cycles are not. We show that the minimum bailout problem is computationally hard, but provide an upper bound on optimal payments and show that the problem has intuitive solutions in specific network structures such as those with disjoint Cycles or a core-periphery structure.
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Distorted Investment Incentives, Regulation, and Equilibrium Multiplicity in a Model of Financial Networks
SSRN Electronic Journal, 2019Co-Authors: Matthew O. Jackson, Agathe PernoudAbstract:In a model of financial networks that admits both debt and equity interdependencies, we show that financial organizations have incentives to choose excessively risky portfolios, and overly correlate their portfolios with those of their counterparties. We show how optimal regulation depends on specific measures of financial centrality that capture how a given organization's portfolio affects the values and defaults of other organizations. Additionally, we provide a comprehensive analysis of the multiplicity of equilibrium values for banks, which increases the fragility of the financial network. Multiplicity arises if and only if there exists a certain type of Dependency Cycle in the network and that those Cycles admit self-fulfilling default cascades. We fully characterize the minimum bailouts needed to ensure systemic solvency. We show that the bailouts needed to eliminate self-fulfilling Cycles of defaults are fully recoverable, while those needed to prevent cascading defaults in the best equilibrium are not.
Sean Pymer - One of the best experts on this subject based on the ideXlab platform.
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Does exercise prescription based on estimated heart rate training zones exceed the ventilatory anaerobic threshold in patients with coronary heart disease undergoing usual-care cardiovascular rehabilitation? A United Kingdom perspective.
European journal of preventive cardiology, 2019Co-Authors: Sean Pymer, Simon Nichols, Jonathon Prosser, Stefan Birkett, Sean Carroll, Lee IngleAbstract:In the United Kingdom (UK), exercise intensity is prescribed from a fixed percentage range (% heart rate reserve (%HRR)) in cardiac rehabilitation programmes. We aimed to determine the accuracy of this approach by comparing it with an objective, threshold-based approach incorporating the accurate determination of ventilatory anaerobic threshold (VAT). We also aimed to investigate the role of baseline cardiorespiratory fitness status and exercise testing mode Dependency (Cycle vs. treadmill ergometer) on these relationships. A maximal cardiopulmonary exercise test was conducted on a Cycle ergometer or a treadmill before and following usual-care circuit training from two separate cardiac rehabilitation programmes from a single region in the UK. The heart rate corresponding to VAT was compared with current heart rate-based exercise prescription guidelines. We included 112 referred patients (61 years (59-63); body mass index 29 kg·m-2 (29-30); 88% male). There was a significant but relatively weak correlation (r = 0.32; p = 0.001) between measured and predicted %HRR, and values were significantly different from each other (p = 0.005). Within this cohort, we found that 55% of patients had their VAT identified outside of the 40-70% predicted HRR exercise training zone. In the majority of participants (45%), the VAT occurred at an exercise intensity <40% HRR. Moreover, 57% of patients with low levels of cardiorespiratory fitness achieved VAT at <40% HRR, whereas 30% of patients with higher fitness achieved their VAT at >70% HRR. VAT was significantly higher on the treadmill than the Cycle ergometer (p < 0.001). In the UK, current guidelines for prescribing exercise intensity are based on a fixed percentage range. Our findings indicate that this approach may be inaccurate in a large proportion of patients undertaking cardiac rehabilitation.
Matthew O. Jackson - One of the best experts on this subject based on the ideXlab platform.
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Credit Freezes, Equilibrium Multiplicity, and Optimal Bailouts in Financial Networks.
2020Co-Authors: Matthew O. Jackson, Agathe PernoudAbstract:We analyze how interdependencies between organizations in financial networks can lead to multiple possible equilibrium outcomes. A multiplicity arises if and only if there exists a certain type of Dependency Cycle in the network that allows for self-fulfilling chains of defaults. We provide necessary and sufficient conditions for banks' solvency in any equilibrium. Building on these conditions, we characterize the minimum bailout payments needed to ensure systemic solvency, as well as how solvency can be ensured by guaranteeing a specific set of debt payments. Bailout injections needed to eliminate self-fulfilling Cycles of defaults (credit freezes) are fully recoverable, while those needed to prevent cascading defaults outside of Cycles are not. We show that the minimum bailout problem is computationally hard, but provide an upper bound on optimal payments and show that the problem has intuitive solutions in specific network structures such as those with disjoint Cycles or a core-periphery structure.
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Distorted Investment Incentives, Regulation, and Equilibrium Multiplicity in a Model of Financial Networks
SSRN Electronic Journal, 2019Co-Authors: Matthew O. Jackson, Agathe PernoudAbstract:In a model of financial networks that admits both debt and equity interdependencies, we show that financial organizations have incentives to choose excessively risky portfolios, and overly correlate their portfolios with those of their counterparties. We show how optimal regulation depends on specific measures of financial centrality that capture how a given organization's portfolio affects the values and defaults of other organizations. Additionally, we provide a comprehensive analysis of the multiplicity of equilibrium values for banks, which increases the fragility of the financial network. Multiplicity arises if and only if there exists a certain type of Dependency Cycle in the network and that those Cycles admit self-fulfilling default cascades. We fully characterize the minimum bailouts needed to ensure systemic solvency. We show that the bailouts needed to eliminate self-fulfilling Cycles of defaults are fully recoverable, while those needed to prevent cascading defaults in the best equilibrium are not.
Lars-erik Thorelli - One of the best experts on this subject based on the ideXlab platform.
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PARLE - Grouping Virtual Channels for Deadlock-Free Adaptive Wormhole Routing
Lecture Notes in Computer Science, 1993Co-Authors: Ziqiang Liu, José Duato, Lars-erik ThorelliAbstract:Recently, intensive research has been done to develop adaptive deadlock-free wormhole routing strategies for interconnection networks. One effective method is to partition the physical network into several virtual networks such that there is no channel Dependency Cycle in each of them even if full or partial adaptive routing strategies are used. However, each physical channel can be split into more virtual channels than the number necessary to set up the virtual networks. The additional virtual channels can be considered as one Resource Pool for all virtual networks. It means the packet which is blocked in one virtual network can borrow one free valid virtual channel from the Resource Pool, returning it to the Resource Pool when it is released. We call this scheme the grouping technique and have applied it to double-y adaptive routing on a 2D mesh network, producing a new fully adaptive routing algorithm called group-double-y. The simulation results show that with heavily loaded network it can double/(increase 26%) the average physical channel utilization under uniform/matrix-transpose traffic pattern. We have also applied the grouping technique in the Turn model on a 2D mesh network, producing a fully adaptive, minimum and nonminimum routing algorithm called group-turn-model. Compared with group-double-y, the simulation results show that with heavily loaded network the group-turn-model increases/decreases the average physical channel utilization by (12%)/(2%) under matrix-transpose/uniform traffic pattern.