El objetivo del estudio fue la validación psicométrica de una escala de elaboración propia para la medición de las perspectivas de estudiantes de pregrado sobre las competencias, los requerimientos de capacitación, la infraestructura y el capital humano que requiere el estado de Tabasco, México, para la recuperación de la actividad económica pos-COVID-19. Los datos se recopilaron en línea de forma anónima, y cada participante brindó su consentimiento informado al comenzar el cuestionario. Se seleccionó una submuestra de 368 estudiantes. Se realizó un análisis factorial exploratorio (AFE), mediante el método de extracción de factores por máxima verosimilitud con rotación Oblimin directo, reportando cargas factoriales superiores a 0.5, cumpliéndose así los criterios mínimos para mantener todos los ítems. Para validar el modelo teórico se realizó un Análisis Factorial Confirmatorio (AFC) que permitió demostrar la validez de la estructura previamente obtenida. Se calcularon los indicadores de ajuste del modelo (SRMR, AGFI, RMSEA, TLI, y CFI), para los cuales se obtuvieron valores satisfactorios. El modelo de medida confirma la estructura teórica a través de los principales indicadores de ajuste, tanto del análisis factorial exploratorio como del confirmatorio. Los resultados presentan una contribución al estudio del proceso de rehabilitación de las actividades económicas posteriores a la pandemia de la COVID-19. Desde una perspectiva metodológica, brinda una herramienta de diagnóstico sólida y confiable para el desarrollo de programas de recuperación económica regional.
{"title":"Perspectivas estudiantiles para la recuperación de la actividad económica después de la pandemia de la COVID-19. Validación de un instrumento","authors":"Deneb Elí Magaña Medina, Norma Aguilar Morales","doi":"10.21640/ns.v14i28.2910","DOIUrl":"https://doi.org/10.21640/ns.v14i28.2910","url":null,"abstract":"El objetivo del estudio fue la validación psicométrica de una escala de elaboración propia para la medición de las perspectivas de estudiantes de pregrado sobre las competencias, los requerimientos de capacitación, la infraestructura y el capital humano que requiere el estado de Tabasco, México, para la recuperación de la actividad económica pos-COVID-19. Los datos se recopilaron en línea de forma anónima, y cada participante brindó su consentimiento informado al comenzar el cuestionario. Se seleccionó una submuestra de 368 estudiantes. Se realizó un análisis factorial exploratorio (AFE), mediante el método de extracción de factores por máxima verosimilitud con rotación Oblimin directo, reportando cargas factoriales superiores a 0.5, cumpliéndose así los criterios mínimos para mantener todos los ítems. Para validar el modelo teórico se realizó un Análisis Factorial Confirmatorio (AFC) que permitió demostrar la validez de la estructura previamente obtenida. Se calcularon los indicadores de ajuste del modelo (SRMR, AGFI, RMSEA, TLI, y CFI), para los cuales se obtuvieron valores satisfactorios. El modelo de medida confirma la estructura teórica a través de los principales indicadores de ajuste, tanto del análisis factorial exploratorio como del confirmatorio. Los resultados presentan una contribución al estudio del proceso de rehabilitación de las actividades económicas posteriores a la pandemia de la COVID-19. Desde una perspectiva metodológica, brinda una herramienta de diagnóstico sólida y confiable para el desarrollo de programas de recuperación económica regional.","PeriodicalId":19411,"journal":{"name":"Nova Scientia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82787739","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Eddy Gabriel Ibarra Ontiveros, Yair Lozano Hernández, Manuel Alejandro Enríquez Rocha, Rosalba Galván Guerra, Mario César Maya Rodríguez
This work solves the regulation and tracking trajectories tasks for four degrees of freedom anthropomorphic robot manipulators. Two controllers are considered: a Super-Twisting controller (ST) and a Proportional Derivative with dynamics compensation (PD+) control. This comparison is carried out through numeric simulation of the dynamic model in the presence of disturbances using Matlab-Simulink software. Also, the tuning procedure of each controller is shown, as well as the stability criteria used for each case. The tunning of the ST controller is done considering the effects produced by an unknown Lipschitz disturbance; this guarantees robustness against this kind of disturbance. The results of the ST controller show the rejection of the disturbance, allowing the correct trajectory tracking. An algorithm based on the inverse kinematics solution is used to generate trajectories and their interpretation in generalized coordinates corresponding to the manipulator’s joint positions obtained through the geometric approach. In addition, we show the workspace, the manipulator parameterization, and the manipulator dynamic model through the Euler-Lagrange motion equations.
{"title":"Super-Twisting Control for trajectory tracking of a four-degree of freedom anthropomorphic robot manipulator","authors":"Eddy Gabriel Ibarra Ontiveros, Yair Lozano Hernández, Manuel Alejandro Enríquez Rocha, Rosalba Galván Guerra, Mario César Maya Rodríguez","doi":"10.21640/ns.v14i28.2723","DOIUrl":"https://doi.org/10.21640/ns.v14i28.2723","url":null,"abstract":"This work solves the regulation and tracking trajectories tasks for four degrees of freedom anthropomorphic robot manipulators. Two controllers are considered: a Super-Twisting controller (ST) and a Proportional Derivative with dynamics compensation (PD+) control. This comparison is carried out through numeric simulation of the dynamic model in the presence of disturbances using Matlab-Simulink software. Also, the tuning procedure of each controller is shown, as well as the stability criteria used for each case. The tunning of the ST controller is done considering the effects produced by an unknown Lipschitz disturbance; this guarantees robustness against this kind of disturbance. The results of the ST controller show the rejection of the disturbance, allowing the correct trajectory tracking. An algorithm based on the inverse kinematics solution is used to generate trajectories and their interpretation in generalized coordinates corresponding to the manipulator’s joint positions obtained through the geometric approach. In addition, we show the workspace, the manipulator parameterization, and the manipulator dynamic model through the Euler-Lagrange motion equations.\u0000 ","PeriodicalId":19411,"journal":{"name":"Nova Scientia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74484637","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Teresa Sandoval Contreras, Maricarmen Íñiguez-Moreno, Luis Garrido Sánchez, J. A. Ragazzo Sánchez, J. A. Narváez Zapata, M. Calderón Santoyo
Jackfruit (Artocarpus heterophyllus Lam.) is a climacteric fruit whit a high commercial value, but susceptible to decay. The most important pathogens for jackfruit R. stolonifer and C. gloeosporioides may interact in different ways. The objectives of this study were to examine the interaction between three fungal species isolated from jackfruit and describe their behavior and interactions as a function of temperature. Three pathogen isolates from jackfruit rots, cultivated individually or paired at 4 cm in a natural medium were used. The growth rate was evaluated at 13, 25, and 35 °C. The Baranyi-Roberts model was used to obtain the radial growth rate. Differences between the growth rate of each fungus are the reference to determine the type of interaction. The effect of temperature of the unpaired isolates was studied by Rosso-Robinson’s model. The experiment was validated by infecting fresh jackfruit whit a mix of spores of all isolates. Rhizopus stolonifer is capable of rapidly colonizing the Petri dish thus reducing the space for the other fungi. The growth rates of unpaired and paired fungal isolates were statistically different showing that interactions between them exist. Rhizopus intermingling the others at 13 and 25 °C whereas, at the same temperatures, Colletotrichum AhCx-02 dominates AhCx-03. In contrast, dominance patterns of the Colletotrichum AhCx-03 strain were higher at 35 °C.
{"title":"Effect of temperature on the interaction between Rhizopus stolonifer and Colletotrichum sp., postharvest pathogens of jackfruit (Artocarpus heterophyllus Lam.)","authors":"Teresa Sandoval Contreras, Maricarmen Íñiguez-Moreno, Luis Garrido Sánchez, J. A. Ragazzo Sánchez, J. A. Narváez Zapata, M. Calderón Santoyo","doi":"10.21640/ns.v14i28.2966","DOIUrl":"https://doi.org/10.21640/ns.v14i28.2966","url":null,"abstract":"Jackfruit (Artocarpus heterophyllus Lam.) is a climacteric fruit whit a high commercial value, but susceptible to decay. The most important pathogens for jackfruit R. stolonifer and C. gloeosporioides may interact in different ways. The objectives of this study were to examine the interaction between three fungal species isolated from jackfruit and describe their behavior and interactions as a function of temperature. Three pathogen isolates from jackfruit rots, cultivated individually or paired at 4 cm in a natural medium were used. The growth rate was evaluated at 13, 25, and 35 °C. The Baranyi-Roberts model was used to obtain the radial growth rate. Differences between the growth rate of each fungus are the reference to determine the type of interaction. The effect of temperature of the unpaired isolates was studied by Rosso-Robinson’s model. The experiment was validated by infecting fresh jackfruit whit a mix of spores of all isolates. Rhizopus stolonifer is capable of rapidly colonizing the Petri dish thus reducing the space for the other fungi. The growth rates of unpaired and paired fungal isolates were statistically different showing that interactions between them exist. Rhizopus intermingling the others at 13 and 25 °C whereas, at the same temperatures, Colletotrichum AhCx-02 dominates AhCx-03. In contrast, dominance patterns of the Colletotrichum AhCx-03 strain were higher at 35 °C.\u0000 \u0000 \u0000 \u0000 ","PeriodicalId":19411,"journal":{"name":"Nova Scientia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76811112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. E. Raimondo, Stefanie Bernardette Costa Gutierrez, Susana Edith Cabrera, C. S. Benimeli
Unsafe management practices and overuse of pesticides have led to environmental contamination and farmworkers poisoning. For this reason, the problem of pesticide exposure must be framed in the socio-cultural and environmental context of the affected communities, analyzing the factors that contribute to the greater risk of exposure of farmworkers and their families, in order to propose educational strategies and develop effective public health strategies. This study evaluated the knowledge, attitudes, and practices regarding local pesticides handling of farmworkers from Singuil town, Catamarca province, northwestern Argentina, and the possible impact of these behavioral patterns on Singuil River. Farmworkers from Singuil town participated through a cross-sectional, face-to-face survey. Subsequently, samples from Singuil River were taken for determination of pesticides residues. Approximately 83 % of those surveyed have worked with pesticides for more than 10 years. Although most workers prepare their pesticide formulations, 25 % of them never use any personal protective equipment, while the remaining 75 % usually use face masks and gloves to protect themselves. Post-spraying personal hygiene practices, such as changing clothes or showering, are often not applied. To reduce health risks, many respondents perform sprinkling at sunset (66.7 %) or early morning (50 %), and avoid it during windy and sunny weather. Besides, they usually burn (58.3 %) or stockpile (41.7 %) empty pesticide containers. In case of poisoning, 91.7 % of workers would go to hospital for medical attention. Glyphosate, mancozeb, and propamocarb are the most commonly used pesticides. Finally, no pesticide residues were detected in the water samples collected from Singuil River.
{"title":"Knowledge, attitudes, and practices on pesticide application among farmworkers from communities in western Catamarca Province, Argentina","authors":"E. E. Raimondo, Stefanie Bernardette Costa Gutierrez, Susana Edith Cabrera, C. S. Benimeli","doi":"10.21640/ns.v14i28.2973","DOIUrl":"https://doi.org/10.21640/ns.v14i28.2973","url":null,"abstract":"Unsafe management practices and overuse of pesticides have led to environmental contamination and farmworkers poisoning. For this reason, the problem of pesticide exposure must be framed in the socio-cultural and environmental context of the affected communities, analyzing the factors that contribute to the greater risk of exposure of farmworkers and their families, in order to propose educational strategies and develop effective public health strategies. This study evaluated the knowledge, attitudes, and practices regarding local pesticides handling of farmworkers from Singuil town, Catamarca province, northwestern Argentina, and the possible impact of these behavioral patterns on Singuil River. Farmworkers from Singuil town participated through a cross-sectional, face-to-face survey. Subsequently, samples from Singuil River were taken for determination of pesticides residues.\u0000Approximately 83 % of those surveyed have worked with pesticides for more than 10 years. Although most workers prepare their pesticide formulations, 25 % of them never use any personal protective equipment, while the remaining 75 % usually use face masks and gloves to protect themselves. Post-spraying personal hygiene practices, such as changing clothes or showering, are often not applied. To reduce health risks, many respondents perform sprinkling at sunset (66.7 %) or early morning (50 %), and avoid it during windy and sunny weather. Besides, they usually burn (58.3 %) or stockpile (41.7 %) empty pesticide containers. In case of poisoning, 91.7 % of workers would go to hospital for medical attention. Glyphosate, mancozeb, and propamocarb are the most commonly used pesticides. Finally, no pesticide residues were detected in the water samples collected from Singuil River.\u0000 \u0000 \u0000 \u0000 ","PeriodicalId":19411,"journal":{"name":"Nova Scientia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90635577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elba Abril Valdez, María José Cubillas Rodríguez, Sandra Elvia Domínguez Ibáñez, Rosario Román Pérez, María Alejandra Córdova Moreno
En el contexto actual, ser joven y universitario plantea nuevos retos y transformaciones que dan lugar a situaciones de estrés que se pueden reflejar en la percepción de felicidad y bienestar. El género influye también en esa percepción, a partir de lo socialmente esperado para cada sexo. Las diferencias en el rol de género, expresado a partir de los atributos asignados socialmente a cada sexo —ya sea masculino, femenino, andrógino o indiferenciado— pueden influir en la forma en que se perciben y se enfrentan los problemas en lo cotidiano, dando lugar a una percepción diferente de la felicidad o el bienestar. Por lo anterior, se plantea como objetivo lo siguiente: analizar, a partir del Índice de Felicidad de Pemberton, la relación entre la percepción de bienestar y el rol de género en estudiantes universitarios de Sonora. Los resultados muestran que la coexistencia de atributos femeninos y masculinos positivos, independientemente del sexo, dan una perspectiva favorable de la interacción con su entorno y de la forma en que resuelven sus problemas las y los jóvenes de la muestra estudiada. La construcción social del género explica la persistencia de roles tradicionales, pero también la emergencia de formas más equilibradas de incorporación de atributos considerados femeninos y masculinos, para una mejor percepción de felicidad y bienestar.
{"title":"Rol de género y percepción de bienestar y felicidad en universitarios del noroeste de México","authors":"Elba Abril Valdez, María José Cubillas Rodríguez, Sandra Elvia Domínguez Ibáñez, Rosario Román Pérez, María Alejandra Córdova Moreno","doi":"10.21640/ns.v14i28.2983","DOIUrl":"https://doi.org/10.21640/ns.v14i28.2983","url":null,"abstract":"En el contexto actual, ser joven y universitario plantea nuevos retos y transformaciones que dan lugar a situaciones de estrés que se pueden reflejar en la percepción de felicidad y bienestar. El género influye también en esa percepción, a partir de lo socialmente esperado para cada sexo. Las diferencias en el rol de género, expresado a partir de los atributos asignados socialmente a cada sexo —ya sea masculino, femenino, andrógino o indiferenciado— pueden influir en la forma en que se perciben y se enfrentan los problemas en lo cotidiano, dando lugar a una percepción diferente de la felicidad o el bienestar. Por lo anterior, se plantea como objetivo lo siguiente: analizar, a partir del Índice de Felicidad de Pemberton, la relación entre la percepción de bienestar y el rol de género en estudiantes universitarios de Sonora. \u0000Los resultados muestran que la coexistencia de atributos femeninos y masculinos positivos, independientemente del sexo, dan una perspectiva favorable de la interacción con su entorno y de la forma en que resuelven sus problemas las y los jóvenes de la muestra estudiada. La construcción social del género explica la persistencia de roles tradicionales, pero también la emergencia de formas más equilibradas de incorporación de atributos considerados femeninos y masculinos, para una mejor percepción de felicidad y bienestar.\u0000 \u0000 \u0000 \u0000 ","PeriodicalId":19411,"journal":{"name":"Nova Scientia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81884030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ángel Emmanuel Zúñiga Tovar, David A. Novelo Casanova, Christian Domínguez, Marcelino García Benítez, Violeta Piña
Due to their frequency and magnitude, urban floods affect different regions of the world. For this reason, several methodologies integrate information on hazard (H) and vulnerability (V) using a "Classic" Risk (R) model for risk analysis. However, this combination of variables generally overestimates the risk in places where the frequency of flooding is low. In this work we propose a model that we call Adjusted Risk (AR) that integrates values of urban proximity (p) to bodies of water, as a tool to assess the risk of floods. The comparison between the R and AR models showed a higher efficiency of AR to reproduce the frequency of floods for 210 cities in Veracruz, while R overestimated the level of risk in cities with low frequency of floods. The correlation values associated with the frequency of flood events for a period of 45 years (1970-2015), allow to establish the utility of the AR model to evaluate the risk of urban floods when using different scales of analysis.
{"title":"A new model to analyze urban flood risk. Case study: Veracruz, Mexico","authors":"Ángel Emmanuel Zúñiga Tovar, David A. Novelo Casanova, Christian Domínguez, Marcelino García Benítez, Violeta Piña","doi":"10.21640/ns.v14i28.2956","DOIUrl":"https://doi.org/10.21640/ns.v14i28.2956","url":null,"abstract":"Due to their frequency and magnitude, urban floods affect different regions of the world. For this reason, several methodologies integrate information on hazard (H) and vulnerability (V) using a \"Classic\" Risk (R) model for risk analysis. However, this combination of variables generally overestimates the risk in places where the frequency of flooding is low. In this work we propose a model that we call Adjusted Risk (AR) that integrates values of urban proximity (p) to bodies of water, as a tool to assess the risk of floods. The comparison between the R and AR models showed a higher efficiency of AR to reproduce the frequency of floods for 210 cities in Veracruz, while R overestimated the level of risk in cities with low frequency of floods. The correlation values associated with the frequency of flood events for a period of 45 years (1970-2015), allow to establish the utility of the AR model to evaluate the risk of urban floods when using different scales of analysis.","PeriodicalId":19411,"journal":{"name":"Nova Scientia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74648498","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper a long-term portfolio optimization model is developed, through the use of economic indicators (CLI and BCI). In this way, an investment portfolio will adjust to the movements of the business cycle, mitigating its risk in the event of possible downturns. The proposed model was tested in Mexico between 1998-2021. The active strategy makes investments in fixed income (Certificados de la Tesorería, CETES) and the market index (Índice de Precios y Cotizaciones, IPC), through operations of 25 % of the capital in monthly decisions. The dynamic investment strategy outperforms market index by 4.3 % in the period analyzed (differences in annual geometric return). In that period, only 5 % of the annual returns of the active strategy were negative, compared to 25.8 % in the market index.
本文通过使用经济指标(CLI和BCI)建立了一个长期投资组合优化模型。通过这种方式，投资组合将根据商业周期的变化进行调整，从而在可能出现的经济衰退中降低风险。该模型于1998年至2021年在墨西哥进行了测试。积极策略通过每月25%的资本运作，投资于固定收益(Certificados de la Tesorería, CETES)和市场指数(Índice de Precios y Cotizaciones, IPC)。动态投资策略在分析期间比市场指数高出4.3%(年度几何回报差异)。在此期间，积极策略的年回报率只有5%为负，而市场指数的年回报率为25.8%。
{"title":"Leading macroeconomic indicators for a dynamic investment strategy","authors":"Ángel Samaniego Alcántar, L. R. Rodríguez-Reyes","doi":"10.21640/ns.v14i28.2839","DOIUrl":"https://doi.org/10.21640/ns.v14i28.2839","url":null,"abstract":"In this paper a long-term portfolio optimization model is developed, through the use of economic indicators (CLI and BCI). In this way, an investment portfolio will adjust to the movements of the business cycle, mitigating its risk in the event of possible downturns. The proposed model was tested in Mexico between 1998-2021. The active strategy makes investments in fixed income (Certificados de la Tesorería, CETES) and the market index (Índice de Precios y Cotizaciones, IPC), through operations of 25 % of the capital in monthly decisions. The dynamic investment strategy outperforms market index by 4.3 % in the period analyzed (differences in annual geometric return). In that period, only 5 % of the annual returns of the active strategy were negative, compared to 25.8 % in the market index.","PeriodicalId":19411,"journal":{"name":"Nova Scientia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86687910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
María Teresa Pérez Maldonado, Julián Bravo Castillero, R. Mansilla, Rogelio Óscar Caballero Pérez
The COVID-19 pandemic has motivated a resurgence in the use of phenomenological growth models for predicting the early dynamics of infectious diseases. These models assume that time is a continuous variable, whereas in the present contribution the discrete versions of Gompertz and Generalized Logistic models are used for early monitoring and short-term forecasting of the spread of an epidemic in a region. The time-continuous models are represented mathematically by first-order differential equations, while their discrete versions are represented by first-order difference equations that involve parameters that should be estimated prior to forecasting. The methodology for estimating such parameters is described in detail. Real data of COVID-19 infection in Cuba is used to illustrate this methodology. The proposed methodology was implemented for the first thirty-five days and was used to predict accurately the data reported for the following twenty days.
{"title":"Discrete Gompertz and Generalized Logistic models for early monitoring of the COVID-19 pandemic in Cuba","authors":"María Teresa Pérez Maldonado, Julián Bravo Castillero, R. Mansilla, Rogelio Óscar Caballero Pérez","doi":"10.21640/ns.v14i29.3162","DOIUrl":"https://doi.org/10.21640/ns.v14i29.3162","url":null,"abstract":"The COVID-19 pandemic has motivated a resurgence in the use of phenomenological growth models for predicting the early dynamics of infectious diseases. These models assume that time is a continuous variable, whereas in the present contribution the discrete versions of Gompertz and Generalized Logistic models are used for early monitoring and short-term forecasting of the spread of an epidemic in a region. The time-continuous models are represented mathematically by first-order differential equations, while their discrete versions are represented by first-order difference equations that involve parameters that should be estimated prior to forecasting. The methodology for estimating such parameters is described in detail. Real data of COVID-19 infection in Cuba is used to illustrate this methodology. The proposed methodology was implemented for the first thirty-five days and was used to predict accurately the data reported for the following twenty days.","PeriodicalId":19411,"journal":{"name":"Nova Scientia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73390257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ángel Jonathan Rodríguez-Villalobos, D. E. Alvarado-Carrillo, Iván Cruz-Aceves, Chrystian Irán Castellón-Lomelí, Luis Miguel López-Montero, M. Hernández-González, David Jaime Giacinti
Introducción: La alta prevalencia de Diabetes Mellitus tipo 2 en México ha posicionado a la retinopatía diabética como la principal causa de ceguera en adultos en edad productiva en México. Por ello, la detección oportuna de este padecimiento es una tarea prioritaria para el sistema público de salud. En el presente artículo se estudia el desempeño de un nuevo algoritmo para la determinación de la forma de la arcada temporal mayor de la retina, mediante el uso de técnicas de segmentación de imágenes y modelado numérico de curvas. Método: La metodología propuesta emplea Filtros Gaussianos de Correspondencia que realzan la geometría de los vasos sanguíneos. Posteriormente, la estructura vascular es segmentada mediante la umbralización global de la imagen realzada. Dicha segmentación es utilizada como entrada para construir un modelo numérico de las arcadas temporales superior en inferior, utilizando funciones Spline. Resultados: La evaluación de desempeño se realizó utilizando 136 imágenes de pixeles. El algoritmo de segmentación automática de venas de la retina mediante el método GMF obtuvo un valor de Accuracy de 0.9852; el algoritmo de modelado numérico dio un resultado de 6.01 pixeles en la métrica de la distancia media al punto más cercano (MDCP). Otro estudio previo reportó 12.33 pixeles. Con respecto al tiempo, se reportó un tiempo promedio de 10.65 segundos por imagen. Discusión: El método propuesto fue capaz de realizar eficientemente el modelado numérico de las arcadas temporales en imágenes de fondo de ojo. Los resultados demuestran que este método es una herramienta computacional útil para el diagnóstico de alteraciones en la anatomía del ojo.
{"title":"Estudio de la vida real sobre el modelado numérico de las arcadas temporales superiores e inferiores en imágenes de fondo de retina","authors":"Ángel Jonathan Rodríguez-Villalobos, D. E. Alvarado-Carrillo, Iván Cruz-Aceves, Chrystian Irán Castellón-Lomelí, Luis Miguel López-Montero, M. Hernández-González, David Jaime Giacinti","doi":"10.21640/ns.v14i28.2745","DOIUrl":"https://doi.org/10.21640/ns.v14i28.2745","url":null,"abstract":"Introducción: La alta prevalencia de Diabetes Mellitus tipo 2 en México ha posicionado a la retinopatía diabética como la principal causa de ceguera en adultos en edad productiva en México. Por ello, la detección oportuna de este padecimiento es una tarea prioritaria para el sistema público de salud. En el presente artículo se estudia el desempeño de un nuevo algoritmo para la determinación de la forma de la arcada temporal mayor de la retina, mediante el uso de técnicas de segmentación de imágenes y modelado numérico de curvas. \u0000Método: La metodología propuesta emplea Filtros Gaussianos de Correspondencia que realzan la geometría de los vasos sanguíneos. Posteriormente, la estructura vascular es segmentada mediante la umbralización global de la imagen realzada. Dicha segmentación es utilizada como entrada para construir un modelo numérico de las arcadas temporales superior en inferior, utilizando funciones Spline. \u0000Resultados: La evaluación de desempeño se realizó utilizando 136 imágenes de pixeles. El algoritmo de segmentación automática de venas de la retina mediante el método GMF obtuvo un valor de Accuracy de 0.9852; el algoritmo de modelado numérico dio un resultado de 6.01 pixeles en la métrica de la distancia media al punto más cercano (MDCP). Otro estudio previo reportó 12.33 pixeles. Con respecto al tiempo, se reportó un tiempo promedio de 10.65 segundos por imagen. \u0000Discusión: El método propuesto fue capaz de realizar eficientemente el modelado numérico de las arcadas temporales en imágenes de fondo de ojo. Los resultados demuestran que este método es una herramienta computacional útil para el diagnóstico de alteraciones en la anatomía del ojo.","PeriodicalId":19411,"journal":{"name":"Nova Scientia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89410949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Introduction: The main research purpose is the identification of the Key Success Factors (KSF) for Social Impact Startups (SST) and how they face an emergency context (like COVID-19 pandemic) under female management as Business Model Innovation (BMI) design to the next normal Methodology: This research applies a known KSF for the author's SST proposal framework published in 2021, composed of 6 factors and 30 variables. Hence, this work is extension research, but now, from the female management point of view. The survey data was on 400 Mexican social startup CEO as survivors in the 2020 second half. Fuzzy set Qualitative Comparative Analysis (fsQCA) extracts different outcomes to get the same solution as KSF for SST under female management. Results: The entrepreneurship profile factor is considered a core condition for male and female management. However, as gender-based features, Key Performance Indicators (KPF) are absent for male management, and Strategic Analysis is absent (STA) for female management as KSF for SST. The research's main value is the female management's characterization as business model innovation design to the next normal. Conclusion: There are subtle differences among gender management as KSF for SST that implying opportunities to take advantage of gender-based features as Business Model Innovation (BMI). The relationship KSF-SST for BMI in the case of female management needs to develop the factors Strategic Analysis (STA); Business Plan (BPL); Market Knowledge (MKK), Key Performance Indicators (KPI), and Value Proposition (VPN). Male management, for another side, the Key Performance Indicators (KPI); Strategic Analysis (STA); Business Plan (BPL), and Market Knowledge (MKK). For both cases, the Entrepreneur Profile (EPR) is strongly present («core condition»), and additionally (VPN) for male management.
{"title":"Social Impact Startups, Business Model innovation and Female Management: Lessons for the Next Normal in Mexico using fsQCA","authors":"Juan Mejía-Trejo","doi":"10.21640/ns.v14i28.2953","DOIUrl":"https://doi.org/10.21640/ns.v14i28.2953","url":null,"abstract":"Introduction: The main research purpose is the identification of the Key Success Factors (KSF) for Social Impact Startups (SST) and how they face an emergency context (like COVID-19 pandemic) under female management as Business Model Innovation (BMI) design to the next normal\u0000Methodology: This research applies a known KSF for the author's SST proposal framework published in 2021, composed of 6 factors and 30 variables. Hence, this work is extension research, but now, from the female management point of view. The survey data was on 400 Mexican social startup CEO as survivors in the 2020 second half. Fuzzy set Qualitative Comparative Analysis (fsQCA) extracts different outcomes to get the same solution as KSF for SST under female management.\u0000Results: The entrepreneurship profile factor is considered a core condition for male and female management. However, as gender-based features, Key Performance Indicators (KPF) are absent for male management, and Strategic Analysis is absent (STA) for female management as KSF for SST. The research's main value is the female management's characterization as business model innovation design to the next normal.\u0000Conclusion: There are subtle differences among gender management as KSF for SST that implying opportunities to take advantage of gender-based features as Business Model Innovation (BMI). The relationship KSF-SST for BMI in the case of female management needs to develop the factors Strategic Analysis (STA); Business Plan (BPL); Market Knowledge (MKK), Key Performance Indicators (KPI), and Value Proposition (VPN). Male management, for another side, the Key Performance Indicators (KPI); Strategic Analysis (STA); Business Plan (BPL), and Market Knowledge (MKK). For both cases, the Entrepreneur Profile (EPR) is strongly present («core condition»), and additionally (VPN) for male management.","PeriodicalId":19411,"journal":{"name":"Nova Scientia","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81015801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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