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Papers by Carlos Alberto Beltran Leon

Research paper thumbnail of Too-Connected-To-Fail Institutions and Payments System’s Stability: Assessing Challenges for Financial Authorities

SSRN Electronic Journal, 2011

The most recent episode of market turmoil exposed the limitations resulting from the traditional ... more The most recent episode of market turmoil exposed the limitations resulting from the traditional focus on too-big-to-fail institutions within an increasingly systemic-crisis-prone financial system, and encouraged the appearance of the too-connected-to-fail (TCTF) concept. The TCTF concept conveniently broadens the base of potential destabilizing institutions beyond the traditional banking-focused approach to systemic risk, but requires methodologies capable of coping with complex, cross-dependent, context-dependent and non-linear systems. After comprehensively introducing the rise of the TCTF concept, this paper presents a robust, parsimonious and powerful approach to identifying and assessing systemic risk within payments systems, and proposes some analytical routes for assessing financial authorities' challenges. Banco de la Republica's approach is based on a convenient mixture of network topology basics for identifying central institutions, and payments systems simulation techniques for quantifying the potential consequences of central institutions failing within Colombian large-value payments systems. Unlike econometrics or network topology alone, results consist of a rich set of quantitative outcomes that capture the complexity, cross-dependency, context-dependency and nonlinearity of payments systems, but conveniently disaggregated and dollar-denominated. These outcomes and the proposed analysis provide practical information for enhanced policy and decision-making, where the ability to measure each institution's contribution to systemic risk may assist financial authorities in their task to achieve payments system's stability.

Research paper thumbnail of Sleep during COVID-19 lockdown: A cross-cultural study investigating job system relevance

Biochemical Pharmacology, 2021

Our study aimed to assess the change in the sleep patterns during the Coronavirus lockdown in fiv... more Our study aimed to assess the change in the sleep patterns during the Coronavirus lockdown in five regions (Austria/Germany, Ukraine, Greece, Cuba and Brazil), using online surveys, translated in each language. Part of the cohort (age 25-65, well-educated) was collected directly during lockdown, to which retrospective crosssectional data from and after lockdown (retrospective) questionnaires were added. We investigated sleep times and sleep quality changes from before to during lockdown and found that, during lockdown, participants had (i) worse perceived sleep quality if worried by COVID-19, (ii) a shift of bedtimes to later hours during workdays, and (iii) a sleep loss on free days (resulting from more overall sleep during workdays in non-system relevant jobs), leading to (iv) a marked reduction of social jetlag across all cultures. For further analyses we directly compared system relevant and system irrelevant jobs, because it was assumed that the nature of the lockdown's consequences is dependent upon system relevance. System relevant jobs were found to have earlier wake-up times as well as shorter total sleep times on workdays, leading to higher social jetlag for people in system relevant jobs. Cultural differences revealed a general effect that participants from Greece and Ukraine had later bedtimes (on both work and free days) and wake-up times (on workdays) than Cuba, Brazil and Austria, irrespective of COVID-19 lockdown restrictions.

Research paper thumbnail of Sleep during COVID-19 lockdown: a cross-cultural pilot study

Our study aimed to assess the change in the sleep patterns during the Coronavirus lockdown in fiv... more Our study aimed to assess the change in the sleep patterns during the Coronavirus lockdown in five regions (Austria/Germany, Ukraine, Greece, Cuba and Brazil), using online surveys, translated in each language. Part of the cohort was collected directly during lockdown, to which retrospective cross-sectional data from and after lockdown (retrospective) questionnaires ware added. We investigated sleep times and sleep quality changes from before to during lockdown and found that, during lockdown, participants had (i) worse perceived sleep quality for those who reported to be worried by COVID-19, (ii) a shift of bedtimes to later hours during workdays, and (iii) a sleep loss on free days (resulting from more overall sleep during workdays), leading to (iv) a marked reduction of social jetlag across all cultures.For further analyses we then split the participants by job (system relevant or not) because it was assumed that the nature of the lockdown’s consequences is dependent upon system ...

Research paper thumbnail of Evaluation of a Low-Cost Commercial Actigraph and Its Potential Use in Detecting Cultural Variations in Physical Activity and Sleep

Sensors (Basel, Switzerland), 2021

The purpose of the present study was to evaluate the performance of a low-cost commercial smartwa... more The purpose of the present study was to evaluate the performance of a low-cost commercial smartwatch, the Xiaomi Mi Band (MB), in extracting physical activity and sleep-related measures and show its potential use in addressing questions that require large-scale real-time data and/or intercultural data including low-income countries. We evaluated physical activity and sleep-related measures and discussed the potential application of such devices for large-scale step and sleep data acquisition. To that end, we conducted two separate studies. In Study 1, we evaluated the performance of MB by comparing it to the GT3X (ActiGraph, wGT3X-BT), a scientific actigraph used in research, as well as subjective sleep reports. In Study 2, we distributed the MB across four countries (Austria, Germany, Cuba, and Ukraine) and investigated physical activity and sleep among these countries. The results of Study 1 indicated that MB step counts correlated highly with the scientific GT3X device, but did d...

Research paper thumbnail of Neural correlates of residual brain activity in PVS patients by means of P300 paradigm using the Subject’s Own Name. (P4.166)

Neurology, Apr 6, 2015

OBJECTIVE:To determine residual electrical cognitive activities in PVS patients by using a P3 aud... more OBJECTIVE:To determine residual electrical cognitive activities in PVS patients by using a P3 auditory stimulation paradigm including SON. To define and localize sources of electrical cognitive activities in these patients. BACKGROUND:Subject’s Own Name (SON) is a unique auditory stimulus which elicits an orienting response. The event-related potentials (ERPs)] have been used to evaluate the activation of brain residual activity in Persistent Vegetative State (PVS) patients. To locate the underlying generators of any residual processing revealed by P3 could be of great interest in terms of characterizing brain functions in these patients. Bayesian Model Averaging (BMA) is an adequate framework for locating residual brain function in PVS patients. DESIGN/METHODS:The P3 component using SON was reconstructed in 5 PVS patients (1 female). The auditory paradigm was validated in 10 healthy volunteers matched by age and gender, using a 32 EEG channels montage. P3 Grand Average was computed and electrical sources were estimated by means of the BMA approach in all groups. RESULTS:A P3 component was observed in response to the SON in 4 of 5 patients in a PVS. No significant differences for latencies between patients and controls were found for the P3 component. Significantly lower activation was also found at the level of source generators in both hemispheres of PVS patients. PVS patients showed structures similar to the controls in response to emotional stimuli (recreated by SON). CONCLUSIONS:The SON elicits a robust P300 response in PVS patients related to attention orienting and possibly to residual (or preserved) semantic processing. Decreased P3 amplitude in PVS patients is indicative of central nervous system damage. The ERPs and source localization methods could be used to explore the neural correlates underlying the detection of our own name in patients with PVS. Disclosure: Dr. Olivares Torres has nothing to disclose. Dr. Iglesias Fuster has nothing to disclose. Dr. Cuspineda Bravo has nothing to disclose. Dr. Sanchez Lopez has nothing to disclose. Dr. Perez Gesen has nothing to disclose. Dr. del Rio Bazan has nothing to disclose. Dr. Beltran Leon has nothing to disclose. Dr. Machado has nothing to disclose.

Research paper thumbnail of Too-Connected-To-Fail Institutions and Payments System’s Stability: Assessing Challenges for Financial Authorities

SSRN Electronic Journal, 2011

The most recent episode of market turmoil exposed the limitations resulting from the traditional ... more The most recent episode of market turmoil exposed the limitations resulting from the traditional focus on too-big-to-fail institutions within an increasingly systemic-crisis-prone financial system, and encouraged the appearance of the too-connected-to-fail (TCTF) concept. The TCTF concept conveniently broadens the base of potential destabilizing institutions beyond the traditional banking-focused approach to systemic risk, but requires methodologies capable of coping with complex, cross-dependent, context-dependent and non-linear systems. After comprehensively introducing the rise of the TCTF concept, this paper presents a robust, parsimonious and powerful approach to identifying and assessing systemic risk within payments systems, and proposes some analytical routes for assessing financial authorities' challenges. Banco de la Republica's approach is based on a convenient mixture of network topology basics for identifying central institutions, and payments systems simulation techniques for quantifying the potential consequences of central institutions failing within Colombian large-value payments systems. Unlike econometrics or network topology alone, results consist of a rich set of quantitative outcomes that capture the complexity, cross-dependency, context-dependency and nonlinearity of payments systems, but conveniently disaggregated and dollar-denominated. These outcomes and the proposed analysis provide practical information for enhanced policy and decision-making, where the ability to measure each institution's contribution to systemic risk may assist financial authorities in their task to achieve payments system's stability.

Research paper thumbnail of Sleep during COVID-19 lockdown: A cross-cultural study investigating job system relevance

Biochemical Pharmacology, 2021

Our study aimed to assess the change in the sleep patterns during the Coronavirus lockdown in fiv... more Our study aimed to assess the change in the sleep patterns during the Coronavirus lockdown in five regions (Austria/Germany, Ukraine, Greece, Cuba and Brazil), using online surveys, translated in each language. Part of the cohort (age 25-65, well-educated) was collected directly during lockdown, to which retrospective crosssectional data from and after lockdown (retrospective) questionnaires were added. We investigated sleep times and sleep quality changes from before to during lockdown and found that, during lockdown, participants had (i) worse perceived sleep quality if worried by COVID-19, (ii) a shift of bedtimes to later hours during workdays, and (iii) a sleep loss on free days (resulting from more overall sleep during workdays in non-system relevant jobs), leading to (iv) a marked reduction of social jetlag across all cultures. For further analyses we directly compared system relevant and system irrelevant jobs, because it was assumed that the nature of the lockdown's consequences is dependent upon system relevance. System relevant jobs were found to have earlier wake-up times as well as shorter total sleep times on workdays, leading to higher social jetlag for people in system relevant jobs. Cultural differences revealed a general effect that participants from Greece and Ukraine had later bedtimes (on both work and free days) and wake-up times (on workdays) than Cuba, Brazil and Austria, irrespective of COVID-19 lockdown restrictions.

Research paper thumbnail of Sleep during COVID-19 lockdown: a cross-cultural pilot study

Our study aimed to assess the change in the sleep patterns during the Coronavirus lockdown in fiv... more Our study aimed to assess the change in the sleep patterns during the Coronavirus lockdown in five regions (Austria/Germany, Ukraine, Greece, Cuba and Brazil), using online surveys, translated in each language. Part of the cohort was collected directly during lockdown, to which retrospective cross-sectional data from and after lockdown (retrospective) questionnaires ware added. We investigated sleep times and sleep quality changes from before to during lockdown and found that, during lockdown, participants had (i) worse perceived sleep quality for those who reported to be worried by COVID-19, (ii) a shift of bedtimes to later hours during workdays, and (iii) a sleep loss on free days (resulting from more overall sleep during workdays), leading to (iv) a marked reduction of social jetlag across all cultures.For further analyses we then split the participants by job (system relevant or not) because it was assumed that the nature of the lockdown’s consequences is dependent upon system ...

Research paper thumbnail of Evaluation of a Low-Cost Commercial Actigraph and Its Potential Use in Detecting Cultural Variations in Physical Activity and Sleep

Sensors (Basel, Switzerland), 2021

The purpose of the present study was to evaluate the performance of a low-cost commercial smartwa... more The purpose of the present study was to evaluate the performance of a low-cost commercial smartwatch, the Xiaomi Mi Band (MB), in extracting physical activity and sleep-related measures and show its potential use in addressing questions that require large-scale real-time data and/or intercultural data including low-income countries. We evaluated physical activity and sleep-related measures and discussed the potential application of such devices for large-scale step and sleep data acquisition. To that end, we conducted two separate studies. In Study 1, we evaluated the performance of MB by comparing it to the GT3X (ActiGraph, wGT3X-BT), a scientific actigraph used in research, as well as subjective sleep reports. In Study 2, we distributed the MB across four countries (Austria, Germany, Cuba, and Ukraine) and investigated physical activity and sleep among these countries. The results of Study 1 indicated that MB step counts correlated highly with the scientific GT3X device, but did d...

Research paper thumbnail of Neural correlates of residual brain activity in PVS patients by means of P300 paradigm using the Subject’s Own Name. (P4.166)

Neurology, Apr 6, 2015

OBJECTIVE:To determine residual electrical cognitive activities in PVS patients by using a P3 aud... more OBJECTIVE:To determine residual electrical cognitive activities in PVS patients by using a P3 auditory stimulation paradigm including SON. To define and localize sources of electrical cognitive activities in these patients. BACKGROUND:Subject’s Own Name (SON) is a unique auditory stimulus which elicits an orienting response. The event-related potentials (ERPs)] have been used to evaluate the activation of brain residual activity in Persistent Vegetative State (PVS) patients. To locate the underlying generators of any residual processing revealed by P3 could be of great interest in terms of characterizing brain functions in these patients. Bayesian Model Averaging (BMA) is an adequate framework for locating residual brain function in PVS patients. DESIGN/METHODS:The P3 component using SON was reconstructed in 5 PVS patients (1 female). The auditory paradigm was validated in 10 healthy volunteers matched by age and gender, using a 32 EEG channels montage. P3 Grand Average was computed and electrical sources were estimated by means of the BMA approach in all groups. RESULTS:A P3 component was observed in response to the SON in 4 of 5 patients in a PVS. No significant differences for latencies between patients and controls were found for the P3 component. Significantly lower activation was also found at the level of source generators in both hemispheres of PVS patients. PVS patients showed structures similar to the controls in response to emotional stimuli (recreated by SON). CONCLUSIONS:The SON elicits a robust P300 response in PVS patients related to attention orienting and possibly to residual (or preserved) semantic processing. Decreased P3 amplitude in PVS patients is indicative of central nervous system damage. The ERPs and source localization methods could be used to explore the neural correlates underlying the detection of our own name in patients with PVS. Disclosure: Dr. Olivares Torres has nothing to disclose. Dr. Iglesias Fuster has nothing to disclose. Dr. Cuspineda Bravo has nothing to disclose. Dr. Sanchez Lopez has nothing to disclose. Dr. Perez Gesen has nothing to disclose. Dr. del Rio Bazan has nothing to disclose. Dr. Beltran Leon has nothing to disclose. Dr. Machado has nothing to disclose.