Documentos donde el Autor es "Callón Rivas, Manuel"
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2022
Tesis Materias > Ciencias Sociales Universidad Internacional Iberoamericana México > Investigación > Tesis Doctorales Cerrado Español El ser humano, en la necesidad de transportar cosas o personas de un punto a otro, bien fuera con fines comerciales o no, siempre ha buscado la forma más eficaz y eficiente de llevar a cabo dicho propósito. En este contexto se las ideado para salvar obstáculos duros y peligrosos como son los mares y océanos que bañan las costas del planeta tierra. Ya en época de los faraones se navegaba con fines comerciales transportando mercancías a lo largo del Nilo. En esa ansia por ir más allá de lo conocido para buscar riquezas, el ser humano, por medio de la navegación, ha conquistado todos los rincones de este basto planeta. Desde los sumerios, fenicios y griegos, pasando por Cristóbal Colón, Hernán Cortes, Francisco Vázquez de Coronado y Luján, Francisco Pizarro y otros muchos, han utilizado el transporte marítimo no sólo con la idea de conquistar tierras nuevas sino transportar sus productos a sus reinos europeos. Hoy en día el transporte por mar de mercancías es el más utilizado por la capacidad de los grandes buques, así como los costes más reducidos que otros medios de transporte. En el estudio del transporte marítimo hay que tener en cuenta, de inicio, los antecedentes que existen al respecto, así como los sujetos que participan en él. Importantes son los sujetos al ser los que hacen posible que el transporte por mar se realice de la forma más efectiva y eficiente posible, moviendo la economía del transporte, tanto de pasajeros como muy especialmente de toda clase de productos, y, por lo tanto, generando mercados en todas las costas del planeta y, como consecuencia de ello, generando riqueza no sólo para los actores directos, aquellos sujetos que intervienen directamente en el negocio del transporte en sí, sino también para los países cuyos puertos reciben las mercancías teniendo como destinatarios finales todos los que habitan en los mismos. Hemos de resaltar que el transporte marítimo es el empleado no sólo para grandes cargas de productos de primer orden como el petróleo, el cemento, arena, gas, madera, etc. sino también para el pequeño consumidor y más si cabe desde el boom de tecnológicas del mercado on-line como AMAZON o ALIBABA entre otras. En cuanto a datos estadísticos la Conferencia de las Naciones Unidas sobre Comercio y Desarrollo, derivado del decimoséptimo período de sesiones celebradas en Ginebra en fecha 11 a 13 de julio de 2018 por el Grupo Intergubernamental de Expertos en Derecho y Política de la Competencial, publica, con fecha 2 de mayo de 2018, que “más del 80% del comercio mundial de mercancías en volumen y más del 70% en valor se transportan por mar y se manejan en los puertos marítimos de todo el mundo. Se estima que el volumen del comercio marítimo mundial crecerá a una tasa anual compuesta del 3,2% en el período 2017-2021. Por consiguiente, el transporte marítimo es muy importante para el comercio y el desarrollo”. La importancia de la realidad objeto de investigación nos hace pensar en soluciones a la falta de legislación uniforme de relevancia jurídica a nivel internacional por la cual se someterían los distintos usuarios de las vías marítimas pertenecientes a diferentes nacionalidades. Estas soluciones, a falta de consenso legislativo, son los seguros marítimos o el sometimiento a arbitraje. Abordaremos la importancia de los seguros en los casos de riesgos de la mar, así como la posibilidad de incluir las cláusulas de arbitraje en los contratos de transporte marítimo que representan el mecanismo idóneo alternativo a la resolución judicial de los conflictos que pudieran surgir cuando algún imprevisto no permite llevar a cabo el negocio de forma pacífica. También llamaremos la atención de la falta de consenso internacional tanto para la aprobación de la normativa que regule los transportes marítimos, como es el caso de las Reglas de Rotterdam, así como la falta de consenso en la legislación referente a arbitraje marítimo. Por lo que abarca el estudio nos inclinamos por llevar a cabo un análisis documental, como técnica e instrumento perteneciente a la investigación cualitativa, así como analítica y sintética, trabajando directamente sobre todo tipo de material documental de forma analítica, buscando soluciones en el estudio de los libros, artículos, conferencias, y otras fuentes que nos permitan, avanzada la investigación, generar proposiciones de los datos elegidos por su utilidad para nuestro estudio, y de esta forma poder exponer de forma clara todas aquellas conclusiones a las que vayamos llegando con la información extraída de los documentos objeto de estudio para nuestra tarea. metadata Callón Rivas, Manuel mail manuelcallon@hotmail.es (2022) Conflictos internacionales en torno a los contratos marítimos de transporte: perspectivas para la resolución de los conflictos y determinar quién responde en caso de incumplimiento. Doctoral thesis, SIN ESPECIFICAR.
<a class="ep_document_link" href="/28573/1/1-s2.0-S0033350626001848-main.pdf"><img class="ep_doc_icon" alt="[img]" src="/style/images/fileicons/text.png" border="0"/></a>
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Objectives To describe long-term trends in mortality attributed to community-acquired pneumonia (CAP) in Chile from 1990 to 2021, stratified by age group, and to evaluate associations with selected socioeconomic and demographic indicators. Study design Ecological, observational, longitudinal study using national secondary data. Methods CAP mortality rates were analyzed for the total population and by age group. Associations with the Human Development Index (HDI), poverty rate, aging index, and life expectancy at birth were examined using a hierarchical analytical approach. This included Spearman's rank correlation for initial exploration, multivariable linear regression to assess adjusted associations, and Prais–Winsten generalized least squares regression to account for first-order autocorrelation and shared temporal trends. Stationarity was evaluated using augmented Dickey–Fuller tests, with supplementary analyses using first-differenced variables. Missing data were imputed using time-based regression or interpolation, with sensitivity analyses performed. Results CAP mortality declined substantially across all age groups over the study period. Strong bivariate correlations were observed between mortality and all socioeconomic indicators; however, these associations were attenuated after adjustment for confounding and temporal autocorrelation. In multivariable and time-series models, HDI and the aging index remained significantly associated with CAP mortality in children (0–9 years) and older adults (≥65 years), whereas associations in intermediate age groups were not robust after accounting for shared secular trends. Poverty and life expectancy did not demonstrate independent associations in adjusted models. Conclusions CAP mortality in Chile has decreased markedly over the past three decades. Associations with socioeconomic indicators are strongest at the extremes of age and persist after accounting for temporal structure, although the ecological design precludes causal inference. These findings highlight the importance of considering demographic and socioeconomic context in population-level analyses of infectious disease outcomes.
Italo Salvador López Muñoz mail italo.lopez@doctorado.unini.edu.mx, Maria Loreto Romero Ladrón de Guevara mail , Christian R. Mejia mail , Shyla Del-Aguila-Arcentales mail , Aldo Alvarez-Risco mail , Neal M. Davies mail , Jaime A. Yáñez mail ,
López Muñoz
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An Integrated Machine Learning and Genomic Framework for Precise Detection of Gastric Cancer
This study presents a novel integrative approach for the analysis of high-dimensional gene expression data, leveraging the complementary strengths of unsupervised clustering and supervised classification. Using K-means clustering, the dataset is stratified into three distinct clusters, revealing intrinsic biological patterns and relationships. The resulting cluster assignments are subsequently employed as pseudo-labels to train machine learning models, including support vector machines, random forest, and a stacking ensemble classifier. To validate and enhance the robustness of clustering, complementary methodologies such as hierarchical clustering and DBSCAN are employed, with results visualized through PCA-driven dimensionality reduction. The high predictive accuracy achieved by the classifiers underscores the separability and reliability of the identified clusters. Furthermore, feature importance analysis highlighted key genetic determinants within each cluster, offering actionable insights into potential biomarkers and critical genomic features. This framework bridges the gap between exploratory unsupervised learning and predictive supervised modeling, providing a scalable and interpretable methodology for analyzing complex genomic datasets. Its applicability extends to biomarker discovery, patient stratification, and other precision medicine applications, emphasizing its utility in advancing genomic research and clinical practice.
Eshmal Iman mail , Sohail Jabbar mail , Shabana Ramzan mail , Ali Raza mail , Farwa Raoof mail , Stefanía Carvajal-Altamiranda mail stefania.carvajal@uneatlantico.es, Vivian Lipari mail vivian.lipari@uneatlantico.es, Imran Ashraf mail ,
Iman
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A novel approach for disease and pests detection in potato production system based on deep learning
Vulnerability of potato crops to diseases and pest infestation can affect its quality and lead to significant yield losses. Timely detection of such diseases can help take effective decisions. For this purpose, a deep learning-based object detection framework is designed in this study to identify and classify major potato diseases and pests under real-world field conditions. A total of 2,688 field images were collected from two research farms in Punjab, Pakistan, across multiple growth stages in various seasonal conditions. Excluding 285 symptoms-free images from the earliest collection led to 2,403 images which were annotated into four biotic-stress classes: blight disease (n = 630), leaf spot disease (n = 370), leafroll virus (viral symptom complex; n = 888), and Colorado potato beetle (larvae/adults; n = 515), indicating class imbalance. Several state-of-the-art models were used including YOLOv8 variants (n/s/m), YOLOv7, YOLOv5, and Faster R-CNN, and the results are discussed in relation to recent potato disease classification studies involving cropped leaf images. Stratified splitting (70% training, 20% validation, 10% testing) was applied to preserve class distribution across all subsets. YOLOv8-medium achieve the best performance with mean average precision (mAP)@0.5 of 98% on the held-out test images. Results for stable 5-fold cross-validation show a mean mAP@0.5 of 97.8%, which offers a balance between accuracy and inference time. Model robustness was evaluated using 5-fold cross-validation and repeated training with different random seeds, showing a low variance of ±0.4% mAP. Results demonstrate promising outcomes under the real-world field conditions, while, broader cross-region and cross-season validation is intended for the future.
Ahmed Abbas mail , Saif Ur Rehman mail , Khalid Mahmood mail , Santos Gracia Villar mail santos.gracia@uneatlantico.es, Luis Alonso Dzul López mail luis.dzul@uneatlantico.es, Aseel Smerat mail , Imran Ashraf mail ,
Abbas
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Concern for mpox infection in Latin America
Background Mpox arrived in Latin America and quickly began to replicate, so it is important to measure the concern it generates among residents. The study aims to assess whether country or other factors are associated with concern about mpox infection in Latin America. Methods The study uses a cross-sectional, multicenter design. Sampling was conducted using non-random snowball sampling. From August to September 2022, concern about being infected with mpox was assessed using a previously validated questionnaire (Cronbach's Alpha: 0.85); it was divided into nine countries and other social variables. Results From 1404 respondents, the majority of respondents were female (60.3%) and young (median age 25 years); also, a few reported that it was a significant problem (6% almost all the time and 11% often) and were concerned (6% almost all the time and 11% often) about the possibility of mpox infection. In multivariate analysis, men (aPR: 0.85; 95% CI: 0.73–0.99; p-value=0.046), younger (aPR: 0.98; 95% CI: 0.97–0.99; p-value<0.001), single (aPR: 0.78; 95% CI: 0.62–0.99; p-value=0.042) and, compared to Peru, those living in Colombia (aPR: 0.75; 95% CI. 0.58–0.97; p-value=0.027) and Costa Rica (aPR: 0.65; 95% CI: 0.44–0.96; p-value=0.032) reported the lowest concern; also, Bolivia (aPR: 1.16; 95% CI: 0.94–1.43; p-value=0.176) and Honduras (aPR: 1.01; 95% CI: 0.80–1.27; p-value=0.943) reported that their concerns tend to be higher. Conclusions There were evident differences across respondents' countries; these baseline results show that the first report was made in many countries that were also significantly affected by mpox and now face a new epidemic threatening public health.
Christian R. Mejia mail , Aldo Alvarez-Risco mail , Luciana Daniela Garlisi-Torales mail , Telmo Raúl Aveiro mail , Jamil Cedillo-Balcázar mail , Néstor Valentin Rocha-Saravia mail , Andrea Retana-González mail , Medally C. Paucar mail , Beatriz Mejia Raudales mail , Jose Armada mail , Shyla Del-Aguila-Arcentales mail , Neal M. Davies mail , Jaime A. Yáñez mail jaime.yanez@unini.edu.mx,
Mejia
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Fish consumption and brain structure: a comprehensive systematic review of observational studies
Background Age-related structural changes in the human brain, including cortical atrophy, reductions in grey and white matter volumes, and the accumulation of small vessel–related lesions such as white matter hyperintensities (WMH) and cerebral microbleeds, represent critical biological substrates underlying cognitive decline and dementia. Fish consumption has been associated with slower cognitive decline and reduced risk of dementia, but a comprehensive evaluation of its relation with brain structures is lacking. Aims The aim of this study was to systematically review current scientific literature providing evidence of relation between fish intake and brain structures in human studies. Methods Studies indexed in two major electronic databases have been screened based on a combination of keywords and MeSH terms. Studies were eligible whether they assessed fish consumption in relation to brain structures in the adult populations. Results A total of 24 studies conducted predominantly on older adults met inclusion criteria. Most brain volume measures were obtained via magnetic resonance imaging (MRI) procedures. Higher fish consumption was associated with reduced severity of white matter hyperintensities (a biomarker of cerebral small vessel disease and white matter damage) and cerebral micro-bleed, preservation of certain brain areas volumes (i.e., hippocampus, temporal lobe and periventricle white matter) and cortical thickness of specific areas (i.e., precuneus, parietal, and cingulate grey matter), among others, compared to lower intake. Some analyses found no association and isolated findings suggested possible adverse associations that were not consistently replicated. Studies reporting null findings may underline the possible relevance of the overall diet (i.e., adherence to the Mediterranean diet). Conclusions Inclusion of fish in a healthy and balanced diet is associated with better white matter grades on MRI and slower progression of white matter hyperintensities and reduction of vascular-related lesions of the aging brain, suggesting a potential role in preventing neurocognitive deterioration. Heterogeneity across studies underscores the need for additional studies.
Justyna Godos mail , Giuseppe Caruso mail , Agnieszka Micek mail , Alberto Dolci mail , Zoltan Ungvari mail , Andrea Lehoczki mail , Lisandra León Brizuela mail , Evelyn Frias-Toral mail , Andrea Di Mauro mail , Mario Siervo mail , Michelino Di Rosa mail , Giuseppe Grosso mail ,
Godos