260 research outputs found
Soluciones periódicas a la ecuación de onda semilineal
No full textLos inicios de la ecuación de onda se remontan al siglo XVIII cuando el matemático Johann Bernoulli planteóuna ecuación en diferencias que buscaba modelar el comportamiento de una cuerda sometida a vibración.Para ello consideró la vibración de un número finito de masas igualmente espaciadas sobre una cuerda sinmasa. Mas tarde Daniel Bernoulli con el paso al límite formuló la siguiente ecuación diferencial parcial (Texto tomado de la fuente).Maestrí
LIFE TABLE OF Orius insidiosus (HEMIPTERA: ANTHOCORIDAE) FEEDING ON Sitotroga cerealella (LEPIDOPTERA: GELECHIIDAE) EGSS
No full textTo use a natural enemy to control an insect pest, it is important to determine the biological parameters of the native populations of the predator. The goal of this study was determinate the biological parameters of O. insidiosus fed on Sitotroga cerealella eggs. A batch of 225 O. insidiosus eggs were laid into bean pods. The bean pods were kept in glass jars, and the eggs and first instar nymphs were counted daily. All nymphs were extracted and individualized in Petri dishes. The presence/absence of exuvie was observed daily as a way to assess the emergence of adults from the nymphal stage. Seventeen adult couples were placed into Petri dishes with a segment of bean pod. The bean pod segments were extracted and replaced daily, counting the number of eggs present on the pods. The life cycle, survival percentage, sex ratio, male/female longevity, pre ovoposition, ovoposition and post ovoposition periods were determined. Finally, fertility life table parameters were estimated. The nymphal development time was 12.0 ± 0.22 days, with 80.47 % ± 3.23 survival, while the total development time was 15.0 ± 0.23 days, with 66.67 % ± 1.90 survival. Of the total adults that emerged, 30.95 % ± 2.38 were females. The female sex ratio was 0.75, and the oviposition period was 0.86 ± 9.21 days with a total fertility of 60.29 ± 7.39 eggs. The data estimated from the fertility life table were: Ro: 28.26, rm: 0.14, T: 24.26, λ: 1.13 and DT: 5.01
Métricas de autor Oscar Fernando Acevedo Arango
No full textInforme de las métricas de autor del Dr. Oscar Fernando Acevedo Arango de las publicaciones indexadas en Google Académico cuyo objetivo es entregar un insumo para el fortalecimiento de las capacidades y potencialidades de los autores de la Universidad Santo Tomás en el posicionamiento y visibilidad de sus publicacionesReport of the author metrics Oscar Fernando Acevedo Arango of the publications indexed in Google Scholar whose objective is to provide an input for the strengthening of the capacities and potentialities of the authors of the Santo Tomás University in the positioning and visibility of their publications.http://unidadinvestigacion.usta.edu.c
Study of a Semilineal Wave Equation
No full textEl presente trabajo de grado en modalidad-investigación consiste en aprender algunas técnicas para resolver problemas de ecuaciones diferenciales para contribuir en el proyecto de investigación institucionalizado “Soluciones Débiles a la Ecuación de Onda Semilineal” de código 4-45-525-16. En este trabajo se estudia concretamente la existencia de soluciones periódicas débiles a la ecuación de onda semilineal cuando el periodo es pi sobre raiz de dos.This research work is for learn some techniques for solving differential equations and to contribute to the research project institutionalized "Soluciones Débiles a la Ecuación de Onda Semilineal" with code 4-45-525-16.
In this paper we study the existence of weak periodic solutions to the semilineal wave equation when the period
is an irrational multiple of pi
Bayesian spatio-temporal disaggregation modeling using a diffusion-SPDE approach: a case study of Aerosol Optical Depth in India
No full textAccurate estimation of Aerosol Optical Depth (AOD) is crucial for understanding climate change and its impacts on public health, as aerosols are a measure of air quality conditions. AOD is usually retrieved from satellite imagery at coarse spatial and temporal resolutions. However, producing high-resolution AOD estimates in both space and time can better support evidence-based policies and interventions. We propose a spatio-temporal disaggregation model that assumes a latent spatio--temporal continuous Gaussian process observed through aggregated measurements. The model links discrete observations to the continuous domain and accommodates covariates to improve explanatory power and interpretability. The approach employs Gaussian processes with separable or non-separable covariance structures derived from a diffusion-based spatio-temporal stochastic partial differential equation (SPDE). Bayesian inference is conducted using the INLA-SPDE framework for computational efficiency. Simulation studies and an application to nowcasting AOD at 550 nm in India demonstrate the model's effectiveness, improving spatial resolution from 0.75° to 0.25° and temporal resolution from 3 hours to 1 hour
A user modeling pipeline for studying polarized political events in social media
No full textThis paper presents a user modeling pipeline to analyze discussions and opinions shared on social media regarding polarized political events (e.g., public polls). The pipeline follows a four-step methodology. First, social media posts and users metadata are crawled. Second, a filtering mechanism is applied to filter spammers and bot users. As a third step, demographics information is extracted out of the valid users, namely gender, age, ethnicity and location information. Finally, the political polarity of the users with respect to the analyzed event is predicted. In the scope of this work, our proposed pipeline is applied to two referendum scenarios (independence of Catalonia in Spain and autonomy of Lombardy in Italy) in order to assess the performance of the approach with respect to the capability of collecting correct insights on the demographics of social media users and of predicting the poll results based on the opinions shared by the users. Experiments show that the method was effective in predicting the political trends for the Catalonia case, but not for the Lombardy case. Among the various motivations for this, we noticed that in general Twitter was more representative of the users opposing the referendum than the ones in favor.Accepted Author ManuscriptWeb Information System
Estimating velocities of infectious disease spread through spatio-temporal log-Gaussian Cox point processes
No full textUnderstanding the spread of infectious diseases such as COVID-19 is crucial for informed decision-making and resource allocation. A critical component of disease behavior is the velocity with which disease spreads, defined as the rate of change between time and space. In this paper, we propose a spatio-temporal modeling approach to determine the velocities of infectious disease spread. Our approach assumes that the locations and times of people infected can be considered as a spatio-temporal point pattern that arises as a realization of a spatio-temporal log-Gaussian Cox process. The intensity of this process is estimated using fast Bayesian inference by employing the integrated nested Laplace approximation (INLA) and the Stochastic Partial Differential Equations (SPDE) approaches. The velocity is then calculated using finite differences that approximate the derivatives of the intensity function. Finally, the directions and magnitudes of the velocities can be mapped at specific times to examine better the spread of the disease throughout the region. We demonstrate our method by analyzing COVID-19 spread in Cali, Colombia, during the 2020-2021 pandemic.29 pages, 46 figures, Journal American Statistican, submitted on 3rd of Septembe
Estimating velocities of infectious disease spread through spatio-temporal log-Gaussian Cox point processes
No full textUnderstanding the spread of infectious diseases such as COVID-19 is crucial for informed decision-making and resource allocation. A critical component of disease behavior is the velocity with which disease spreads, defined as the rate of change between time and space. In this paper, we propose a spatio-temporal modeling approach to determine the velocities of infectious disease spread. Our approach assumes that the locations and times of people infected can be considered as a spatio-temporal point pattern that arises as a realization of a spatio-temporal log-Gaussian Cox process. The intensity of this process is estimated using fast Bayesian inference by employing the integrated nested Laplace approximation (INLA) and the Stochastic Partial Differential Equations (SPDE) approaches. The velocity is then calculated using finite differences that approximate the derivatives of the intensity function. Finally, the directions and magnitudes of the velocities can be mapped at specific times to examine better the spread of the disease throughout the region. We demonstrate our method by analyzing COVID-19 spread in Cali, Colombia, during the 2020-2021 pandemic
Economic Analysis of Business Adaptability Strategies in the Post-Pandemic Construction Sector in Cúcuta, Norte de Santander (2020-2024)
No full textDigitalEn este sentido, el presente trabajo de grado aborda, desde una perspectiva económica, las estrategias de adaptabilidad implementadas por los negocios del sector de la construcción en Cúcuta, en el marco del periodo 2020–2024 de post pandemia. Bajo la forma de un estudio descriptivo-comparativo, se aborda el desarrollo del sector bajo condiciones de alta incertidumbre, precarización laboral e incluso desafíos logísticos, identificando los impactos negativos y las oportunidades emergentes. Con el uso de encuestas, estudios de caso y herramientas analíticas como los diagramas causales, las 5 fuerzas de Porter para comprender las dinámicas comerciales, los avances digitalización, la transformación cultural interna de las empresas y los retos estructurales aún vigentes. A pesar de las dificultades, la resiliencia del sector se ha fortalecido a través de la innovación tecnológica, la cooperación empresarial y una creciente conciencia sobre la sostenibilidad. Con este análisis se ofrecen recomendaciones aplicables para la mejora de políticas públicas, la consolidación del tejido empresarial y la preparación ante futuras crisis.In this regard, the present thesis addresses, from an economic perspective, the adaptability strategies implemented by businesses in the construction sector in Cúcuta during the post-pandemic period of 2020–2024. Through a descriptive-comparative study, it examines the development of the sector under conditions of high uncertainty, labor precariousness, and even logistical challenges, identifying both negative impacts and emerging opportunities. Utilizing surveys, case studies, and analytical tools such as causal diagrams and Porter’s Five Forces to understand commercial dynamics, the study explores the progress of digitalization, internal cultural transformation within companies, and the ongoing structural challenges. Despite the difficulties, the resilience of the sector has been strengthened through technological innovation, business cooperation, and a growing awareness of sustainability. This analysis offers actionable recommendations for improving public policy, consolidating the business fabric, and preparing for future crises.Introducción .................................................................................................................................. 23
Problema de Investigación ............................................................................................................ 25
Problematización........................................................................................................................... 25
Planteamiento de la Problemática ................................................................................................. 26
Formulación de la Problemática ................................................................................................... 33
Sistematización del Problema ....................................................................................................... 33
Objetivos ....................................................................................................................................... 34
Objetivo General ........................................................................................................................... 34
Objetivos Específicos.................................................................................................................... 34
Justificación .................................................................................................................................. 35
Marco Referencial ......................................................................................................................... 37
Antecedentes ................................................................................................................................. 37
Antecedentes Internacionales ........................................................................................................ 37
Antecedentes Nacionales .............................................................................................................. 39
Antecedentes Regionales .............................................................................................................. 39
Bases Teóricas .............................................................................................................................. 40
Marco Teórico ............................................................................................................................... 43
Marco Conceptual ......................................................................................................................... 44
Adaptabilidad ................................................................................................................................ 44
Pandemia ....................................................................................................................................... 45
Análisis ......................................................................................................................................... 45
Resiliencia ..................................................................................................................................... 45
Estrategia....................................................................................................................................... 45
Marco Legal .................................................................................................................................. 45
Marco Espacio - Temporal ............................................................................................................ 46
Hipótesis ....................................................................................................................................... 46
Diseños Metodológicos ................................................................................................................. 47
Tipo de Investigación .................................................................................................................... 47
Método de Investigación ............................................................................................................... 47
Tipo de Estudio ............................................................................................................................. 47
Instrumentos de Recolección de Información............................................................................... 47
Encuesta ........................................................................................................................................ 47
Cuestionario .................................................................................................................................. 48
Población....................................................................................................................................... 48
Muestra ......................................................................................................................................... 48
Sistematización de Variables ........................................................................................................ 49
Marco Administrativo ................................................................................................................... 49
Cronograma de Trabajo ................................................................................................................ 50
Desarrollo Objetivo Específicos ................................................................................................... 53
Cambios Permanentes Sugeridos para Fortalecer la Resiliencia .................................................. 73
Inversión en Capacitación del Personal ........................................................................................ 73
Percepción Sobre la Capacidad de Adaptación ............................................................................ 74
Importancia de la Adopción Tecnológica ..................................................................................... 75
Políticas Gubernamentales ............................................................................................................ 75
Evolución del Sector ..................................................................................................................... 76
Avances Estructurales y Tecnológicos ......................................................................................... 77
Transformación Cultural y Enfoque en el Talento Humano ......................................................... 77
Retos Persistentes y Brechas por Cerrar ....................................................................................... 78
Perspectiva de Largo Plazo y Resiliencia Futura .......................................................................... 78
Voces del Sector: Una Mirada Desde la Experiencia ................................................................... 79
Puestas en Práctica que Impulsaron la Evolución Post-Pandemia ................................................ 80
El Impacto de la Evolución del Sector de la Construcción en la vida Cotidiana de los Cucuteños................ 82
Mejoras en la Vivienda y el Entorno Familiar .............................................................................. 83
Reconfiguración de la Economía Familiar ................................................................................... 83
Reducción del Estrés Familiar y Aumento del Tiempo de Convivencia ...................................... 84
Impacto en los Problemas Familiares y la Cohesión Social ......................................................... 84
Perspectiva a Largo Plazo: Un Futuro más Estable para las Familias Cucuteñas ........................ 85
Mejoramiento de la Tasa de Violencia Intrafamiliar .................................................................... 85
Conclusiones ................................................................................................................................. 88
Referencias Bibliográficas ............................................................................................................ 90
Apéndices ...................................................................................................................................... 94PregradoProfesional en Comercio Exterio
Perspectives of the River Plate around the time of Rosas : an analysis based upon the personal correspondence, private memoirs and published accounts of British settlers, as well as works by creole authors
No full textThis thesis draws inspiration from the emergence of cultural studies as an academic
pursuit, in addition to the current renewal of interest in the relationship between
literary works and their socio-cultural milieux, to bring together an assortment of
textual traces pertaining to the River Plate around the era of Juan Manuel de Rosas,
governor of Buenos Aires and de facto dictator of Argentina for most of the period
1829-1852. The main texts analysed range from private documents relating to two
Scottish settler families, through accounts published by British citizens with first-hand
knowledge of the region (Un inglés, Cinco años en Buenos Aires and
Beaumont, Travels in Buenos Ayres and the Adjacent Provinces), to three influential
pieces of early Argentinian literature (Echeverria's El matadero, Mármol's Amalia
and Sarmiento's Facundo). One justification of this apparently eclectic approach lies
in the prominence accorded to the incomer in the thought of liberal Platine
intellectuals, a concern evinced in their literary production.
The methodology involves examining the representation of certain
fundamental topics across this range of written artefacts, observing frequent points of
thematic convergence amongst the various texts. In this fashion, I construct an image
of the River Plate region around the Rosas period, whilst also appraising the degree
to which early British settlers matched the idealized notion of the immigrant present
in liberal creole writings.
The study is divided into four main chapters, supplemented by an
introduction, conclusion and appendix. The first chapter summarizes the historical
context of the young Platine republics; the second deals with the themes of society,
community and family, the third focuses upon religion; the fourth considers
perspectives of politics, dictatorship and civil war. The appendix consists of an
unpublished settler autobiography, a remarkable account of the tribulations faced on
a daily basis in the developing Argentina
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