Mecanismos de transmisión de la política monetaria a la renta fija en Colombia

21 páginas incluye ilustraciones y diagramasEn este trabajo se realiza un Vector Autorregresivo (VAR) con 4 variables diferentes: la tasa repo de intervención del Banco de la República, la DTF y la tasa de negociación de los TES con vencimiento en octubre de 2015 y junio de 2020. La idea general es identificar en que momento y en que magnitud los movimientos de la tasa repo de intervención afectan a las demás variables, lo cual permitirá a los inversionistas tomar decisiones en sus posiciones en títulos de renta y tasa fija. Se tomaron datos mensuales de estas variables desde febrero de 2007 a enero de 2015. Primero se realizan las pruebas de raíz unitaria para saber si las series son estacionarias. Cómo estas series no son estacionarias se tomaron los cambios cambios porcentuales de estas. Luego se escoge la cantidad de rezagos a considerar utilizando varios criterios estadísticos. Se calcula el VAR y a este resultado se le hace un análisis de impulso respuesta con el cual se pudo concluir que cuando aumenta la tasa repo, en el corto plazo, todos los títulos suben en tasa y caen de precio, pero en el mediano y largo plazo, los títulos con mayor vencimiento caen en tasa y suben de precio.​ Nota: Para consultar la carta de autorización de publicación de este documento por favor copie y pegue el siguiente enlace en su navegador de internet: http://intellectum.unisabana.edu.co/handle/10818/1681

Carbazole-based Diradicals for Dynamic Covalent Chemistry

Dynamic covalent chemistry (DCC) is focused on the creation of structural scaffolds based on chemical components that interact through strong but reversible bonds. In fact, dynamic covalent bonds receive lot of attention because of their unique feature to become reversible under mild conditions.1 conjugated diradical compounds has emerged as essential building blocks in DCC.2 In this work, we will review our most recent works on the formation of stimuli-responsive cyclophanes by self-assembly of carbazole-based diradicals. To this end, we use a combined experimental and theoretical approach that links vibrational spectroscopy with DFT calculations. In this sense, it is interesting to note that we have recently demonstrated the potential of a para-substituted carbazole with terminal dicyanomethylene (DCM) groups to act as building blocks in DCC.3 This quinoid carbazole monomer transforms to a macrocycle cyclophane upon soft external stimuli (temperature, pressure, light), showing strong chromic features. In addition, we have also recently explored how the different DCM substitution position affects the interesting chromoactive properties of carbazole compounds.4 Finally, we are currently exploring the effect of the elongation of the carbazole backbone on the formation of stimuli-responsive cyclophanes.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Multiresponsive chromic soft materials: formation of strongly coupled σ-dimers from IndoloCarbazole-based biradicaloids

Dynamic covalent chemistry is focused on the creation of structural scaffolds based on chemical components that interact through strong but reversible bonds. In fact, dynamic covalent bonds receive lot of attention because of their unique feature to become reversible under mild conditions.1 π-conjugated biradical compounds has emerged as essential building blocks in DCC (dynamic covalent chemistry).2 We have recently demonstrated the potential of a para-substituted carbazole with terminal dicyanomethylene groups to act as building blocks in DCC.3 In fact, this quinoid carbazole monomer transform to a macrocycle cyclophane upon soft external stimuli (temperature, pressure, light), showing strong chromic features. Here, we explore the effect of the elongation of the carbazole backbone on the formation of stimuli-responsive cyclophanes by self-assembly. To this end, we use a join experimental and theoretical approach that links vibrational spectroscopy (Raman and IR) with DFT calculationsUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Formation of Cyclophane Macrocycles in Carbazole-Based Biradicaloids: Impact of the Dicyanomethylene Substitution Position

We have recently demonstrated that carbazole-based biradicaloids are promising building blocks in dynamic covalent chemistry. To elucidate their intriguing dynamic covalent chemical properties, it is necessary to understand the physical origin of their biradical nature. To this end, here we focus on two quinoid carbazole systems substituted with dicyanomethylene (DCM) groups via para (p-Cz-alkyl) or meta positions (m-Cz-ph), which are able to form cyclophane macrocycles by the formation of long C–C bonds between the bridgehead carbon atoms linked to the DCM groups. We aim at exploring the following questions: (i) How is the biradicaloid character of a quinoid carbazole affected by the substitution position of the DCM groups? (ii) How is the stability of the resulted cyclophane aggregate attained? (iii) How is the dynamic interconversion between the carbazole-based monomers and cyclophane aggregates affected by this subtle change in the substitution pattern position? Density functional theory-based calculations reveal that both p-Cz-alkyl and m-Cz-ph are open-shell biradicals in the ground electronic state, with the DCM substitution in the meta position resulting in a more pronounced biradical character. In contrast, the derivatization via the nitrogen of the carbazole unit is not predicted to affect the biradicaloid character. The spontaneous nature of the cyclophane-based macrocycle formation (i.e., the cyclic tetramer in p-Cz-alkyl and the cyclic trimer and the tetramer in m-Cz-ph) is supported by the negative relative Gibbs free energies calculated at 298 K. Interestingly, cyclic oligomers in which the DCM groups are inserted in the meta position tend to adopt folded conformations with attractive π–π interactions resulting in more stable aggregates; in contrast, note that an extended ring-shaped conformation is acquired for (p-Cz-alkyl)4. In addition, the larger spin density on the bridgehead carbon atom in the meta-substituted system strengthens the bridging C–C bond in the aggregate forms, hampering its dissociation. In fact, the C–C bond dissociation of (m-Cz-ph)4 and (m-Cz-ph)3 was suppressed in solution state, although it was achieved in solid state in response to soft external stimuli (i.e., temperature and grinding). In summary, we report a very comprehensive study aiming at elucidating the challenging chemical properties of carbazole-based biradicaloid systems.The work at the University of Málaga was funded by the MINECO (CTQ2015-66897) and Junta de Andalucía (P09-FQM-4708) projects. The work at the University of Alicante was supported by the MINECO (CTQ2014-55073) and Generalitat Valenciana (AICO/2018/175) projects

Resultados Semilleros de Investigación 2009-2010

La publicación recoge los doce informes finales de investigación presentados por los estudiantes de ocho Semilleros 1 y cuatro Semilleros 2, correspondientes a la convocatoria 2009–2010 y se constituye en el Número 25 de la Serie de Investigaciones en Construcción, si bien este es el primer Número publicado en formato digital que UNIJUS se permite poner a disposición no sólo de la comunidad universitaria, sino también de la sociedad colombiana e internacional, interesada en los temas estudiados por los jóvenes investigadores de la Facultad de Derecho, Ciencias Políticas y Sociales de la Universidad Nacional de Colombia

XVII International Congress of Control Electronics and Telecommunications: "Advanced Science, Technology and Innovation to move towards a new socio-technical system: Sustainable Social Transformation"

Contenido: Approach to the diagnostic of cesarean birth using bio-inspired models. ; Design of a tool in a virtual reality environment to manipulate anatomical models. ; The effect of COVID-19 restrictions on the electricity price forecasting models. ; Depression prevention through artificial intelligence. ; State of the art in Prototypes as complements to the learning of the Colombian Sign Language (LSC). ; A computational proposal for gene expression deterministic analysis in associated disorders to depression and anxiety. ; Evaluation of postural stability from the predictability of the measurement of the center of pressure. ; Psychophysiological Analysis of Sound Stimuli.; Delphi method for the identification of relevant variables in the development of low-power photovoltaic solar projects. ; Socioeconomic impact of a refrigerator powered by a photovoltaic system in La Guajira. ; Energy Efficiency: characteristics that allow the reduction of greenhouse gases in. ; Possibilities for the implementation of a bioreactor from organic waste. ; Energy Potential with Small Hydroelectric Power Plants in Non- interconnected Zones of Colombia. ; Energy Potential in Photovoltaic Solar Solutions in Non-Interconnected Areas of Colombia. ; Photovoltaic system, towards the energy transition from home. ; Blockchain model to increase the transparency of public sector processes. ; Intelligent agricultural irrigation prescription system based on sensor networks and crop modeling. ; Design and implementation of a digital modulation classification system using intelligent algorithms. ; A mobile application proposal to minimize intermediation during agricultural process distribution of products in supply chain. ; Accompanying strategy for the social appropriation of new technologies in vulnerable agricultural communities: case in communities producing Gulupas fruits (Passiflora edulis Sims). ; Predictive model of transparency as an indicator of Public Policies. ; Smart system for recognition of ripening level in blackberry fruits. ; Project-based learning as an alternative methodology for technological education in electronics. ; Design and construction of an automated system for N. ; Four bar mechanisms (FBM) and their Software-Based applications: a reviewFT aquaponic culture of Red Carp and Crespa Lettuce. ; Intelligent search implementation for the construction of states of the art: a python application. ; Indoor and Outdoor propagation models on 5G environments: state of the art. ;The electronic detection of offenders (DOO) in the District Secretary of mobility of Bogotá: a step forward in the configuration of the concept of digital citizenship in Colombia. ; Monitoring through ICT of Mobility: technological collaborative feature to incorporate IoT in a Smart City. ; Characterization model of asphalt mixtures using digital image processing. ; Review: identification of diseases and/or pests in fruit trees through image processing techniques and artificial intelligence. ; VRS applicated to Nasa Yuwe language. ; Application of Pix2Pix for edge reconstruction in images. ; Brushless DC Motor Control System for Active Myoelectric Prosthesis. ; Implementation of a Water Conductivity Measuring System. ; 2 DOF robot programmed with MatLab® (guide and Peter Corke) and Arduino uno for writing alphabetical characters. ; Simulator of the behavior of the center of mass in a quadruped robot. ; Biomimetic prototype for flapping movement of batsContent: Contenido: Approach to the diagnostic of cesarean birth using bio-inspired models. ; Design of a tool in a virtual reality environment to manipulate anatomical models. ; The effect of COVID-19 restrictions on the electricity price forecasting models. ; Depression prevention through artificial intelligence. ; State of the art in Prototypes as complements to the learning of the Colombian Sign Language (LSC). ; A computational proposal for gene expression deterministic analysis in associated disorders to depression and anxiety. ; Evaluation of postural stability from the predictability of the measurement of the center of pressure. ; Psychophysiological Analysis of Sound Stimuli.; Delphi method for the identification of relevant variables in the development of low-power photovoltaic solar projects. ; Socioeconomic impact of a refrigerator powered by a photovoltaic system in La Guajira. ; Energy Efficiency: characteristics that allow the reduction of greenhouse gases in. ; Possibilities for the implementation of a bioreactor from organic waste. ; Energy Potential with Small Hydroelectric Power Plants in Non- interconnected Zones of Colombia. ; Energy Potential in Photovoltaic Solar Solutions in Non-Interconnected Areas of Colombia. ; Photovoltaic system, towards the energy transition from home. ; Blockchain model to increase the transparency of public sector processes. ; Intelligent agricultural irrigation prescription system based on sensor networks and crop modeling. ; Design and implementation of a digital modulation classification system using intelligent algorithms. ; A mobile application proposal to minimize intermediation during agricultural process distribution of products in supply chain. ; Accompanying strategy for the social appropriation of new technologies in vulnerable agricultural communities: case in communities producing Gulupas fruits (Passiflora edulis Sims). ; Predictive model of transparency as an indicator of Public Policies. ; Smart system for recognition of ripening level in blackberry fruits. ; Project-based learning as an alternative methodology for technological education in electronics. ; Design and construction of an automated system for N. ; Four bar mechanisms (FBM) and their Software-Based applications: a reviewFT aquaponic culture of Red Carp and Crespa Lettuce. ; Intelligent search implementation for the construction of states of the art: a python application. ; Indoor and Outdoor propagation models on 5G environments: state of the art. ;The electronic detection of offenders (DOO) in the District Secretary of mobility of Bogotá: a step forward in the configuration of the concept of digital citizenship in Colombia. ; Monitoring through ICT of Mobility: technological collaborative feature to incorporate IoT in a Smart City. ; Characterization model of asphalt mixtures using digital image processing. ; Review: identification of diseases and/or pests in fruit trees through image processing techniques and artificial intelligence. ; VRS applicated to Nasa Yuwe language. ; Application of Pix2Pix for edge reconstruction in images. ; Brushless DC Motor Control System for Active Myoelectric Prosthesis. ; Implementation of a Water Conductivity Measuring System. ; 2 DOF robot programmed with MatLab® (guide and Peter Corke) and Arduino uno for writing alphabetical characters. ; Simulator of the behavior of the center of mass in a quadruped robot. ; Biomimetic prototype for flapping movement of bat

Evolution over Time of Ventilatory Management and Outcome of Patients with Neurologic Disease∗

OBJECTIVES: To describe the changes in ventilator management over time in patients with neurologic disease at ICU admission and to estimate factors associated with 28-day hospital mortality. DESIGN: Secondary analysis of three prospective, observational, multicenter studies. SETTING: Cohort studies conducted in 2004, 2010, and 2016. PATIENTS: Adult patients who received mechanical ventilation for more than 12 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among the 20,929 patients enrolled, we included 4,152 (20%) mechanically ventilated patients due to different neurologic diseases. Hemorrhagic stroke and brain trauma were the most common pathologies associated with the need for mechanical ventilation. Although volume-cycled ventilation remained the preferred ventilation mode, there was a significant (p < 0.001) increment in the use of pressure support ventilation. The proportion of patients receiving a protective lung ventilation strategy was increased over time: 47% in 2004, 63% in 2010, and 65% in 2016 (p < 0.001), as well as the duration of protective ventilation strategies: 406 days per 1,000 mechanical ventilation days in 2004, 523 days per 1,000 mechanical ventilation days in 2010, and 585 days per 1,000 mechanical ventilation days in 2016 (p < 0.001). There were no differences in the length of stay in the ICU, mortality in the ICU, and mortality in hospital from 2004 to 2016. Independent risk factors for 28-day mortality were age greater than 75 years, Simplified Acute Physiology Score II greater than 50, the occurrence of organ dysfunction within first 48 hours after brain injury, and specific neurologic diseases such as hemorrhagic stroke, ischemic stroke, and brain trauma. CONCLUSIONS: More lung-protective ventilatory strategies have been implemented over years in neurologic patients with no effect on pulmonary complications or on survival. We found several prognostic factors on mortality such as advanced age, the severity of the disease, organ dysfunctions, and the etiology of neurologic disease