Universidad Nacional de Trujillo: Publicaciones Científicas
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Traveling waves in a delayed reaction-diffusion SVIR epidemic model with generalized incidence function and imperfect vaccination
Get PDFThis paper is concerned with traveling wave solutions for a delayed reaction-diffusion SVIR epidemic model that includes both general incidence function and imperfect vaccination. In the model, the spread of infection in space is explicitly taken into account by using a heterogeneous environment; it takes into consideration the delay in immune response and inefficiency in vaccinations. The analysis carried out below shows that the basic reproduction number Ro will be a critical value for determining the existence of traveling waves. More precisely, when Ro > 1 there exists a minimal wave speed ρ* > 0 such that the system admits nontrivial traveling wave solutions for ρ ≥ ρ* whereas no such solutions exist for ρ < ρ*. On the other hand, if Ro ≤ 1, there are no traveling wave solutions. The introduction of delays and imperfect vaccination adds richness and complexity to the dynamics, such as possible wave speed adjustments and pattern formations, which are hallmarks of complex systems. This work develops a theoretical framework that shall guide the understanding of how delays, spatial spread, and control measures interact in epidemic systems and offers insights applicable to real-world infectious disease dynamics. Numerical simulations for some typical nonlinear incidence functions are given in the last to illustrate the existence of traveling waves.This paper is concerned with traveling wave solutions for a delayed reaction-diffusion SVIR epidemic model that includes both general incidence function and imperfect vaccination. In the model, the spread of infection in space is explicitly taken into account by using a heterogeneous environment; it takes into consideration the delay in immune response and inefficiency in vaccinations. The analysis carried out below shows that the basic reproduction number Ro will be a critical value for determining the existence of traveling waves. More precisely, when Ro > 1 there exists a minimal wave speed ρ* > 0 such that the system admits nontrivial traveling wave solutions for ρ ≥ ρ* whereas no such solutions exist for ρ < ρ*. On the other hand, if Ro ≤ 1, there are no traveling wave solutions. The introduction of delays and imperfect vaccination adds richness and complexity to the dynamics, such as possible wave speed adjustments and pattern formations, which are hallmarks of complex systems. This work develops a theoretical framework that shall guide the understanding of how delays, spatial spread, and control measures interact in epidemic systems and offers insights applicable to real-world infectious disease dynamics. Numerical simulations for some typical nonlinear incidence functions are given in the last to illustrate the existence of traveling waves.This paper is concerned with traveling wave solutions for a delayed reaction-diffusion SVIR epidemic model that includes both general incidence function and imperfect vaccination. In the model, the spread of infection in space is explicitly taken into account by using a heterogeneous environment; it takes into consideration the delay in immune response and inefficiency in vaccinations. The analysis carried out below shows that the basic reproduction number Ro will be a critical value for determining the existence of traveling waves. More precisely, when Ro > 1 there exists a minimal wave speed ρ* > 0 such that the system admits nontrivial traveling wave solutions for ρ ≥ ρ* whereas no such solutions exist for ρ < ρ*. On the other hand, if Ro ≤ 1, there are no traveling wave solutions. The introduction of delays and imperfect vaccination adds richness and complexity to the dynamics, such as possible wave speed adjustments and pattern formations, which are hallmarks of complex systems. This work develops a theoretical framework that shall guide the understanding of how delays, spatial spread, and control measures interact in epidemic systems and offers insights applicable to real-world infectious disease dynamics. Numerical simulations for some typical nonlinear incidence functions are given in the last to illustrate the existence of traveling waves
Some Variants of Wayment's Mean Value Theorem for Integrals
Get PDFThis note deals with some variants of Wayment’s Mean Value Theorem for integrals. Our approach is rather elementary and does not use advanced techniques from analysis. The simple auxiliary functions were used to prove the results.This note deals with some variants of Wayment’s Mean Value Theorem for integrals. Our approach is rather elementary and does not use advanced techniques from analysis. The simple auxiliary functions were used to prove the results.This note deals with some variants of Wayment’s Mean Value Theorem for integrals. Our approach is rather elementary and does not use advanced techniques from analysis. The simple auxiliary functions were used to prove the results
Tangencias para Funcoes Potencia de Expoente Inteiro
Get PDFConsidering a power function f(x) = x^n with exponent n as a positive integer, we show that, at each of its points, there exists a unique polynomial function of degree n − 1 that is tangent to it at that point. Similarly, we verify that every power function h(x) = x^k with exponent k as a negative integer is tangent, at each of its points, to a function of the form l(x) =Sa^t.x^t, where the exponents t are integers between k + 1 and −1.Considerando uma funcao potencia f(x) = x^n com expoente n inteiro positivo, mostramos que, para cada um de seus pontos, existe uma única funcao polinomial de grau n − 1 que a tangencia neste ponto. Semelhantemente, verificamos que toda funcao potencia h(x) = x^k, com expoente k inteiro negativo, é tangente, em cada um de seus pontos, a uma funcao da forma l(x) =Suma: a^t.x^t, com expoentes t inteiros entre k + 1 e −1.Considerando uma funcao potencia f(x) = x^n com expoente n inteiro positivo, mostramos que, para cada um de seus pontos, existe uma única funcao polinomial de grau n − 1 que a tangencia neste ponto. Semelhantemente, verificamos que toda funcao potencia h(x) = x^k, com expoente k inteiro negativo, é tangente, em cada um de seus pontos, a uma funcao da forma l(x) =Suma: a^t.x^t, com expoentes t inteiros entre k + 1 e −1
Hermenéutica y tecnología: la educación superior universitaria
Get PDFEl objetivo del estudio, desde una visión hermenéutica, gira en comprender la posición de la universidad en relación con la tecnología en contextos complejos. Como aspectos de mediación interpretativa se ha tomado en cuenta el lenguaje, como representación no solo del campo teórico sino de la acción, en su dinámica constitutiva de ejercicio de cierto poder. Asimismo, el análisis de la tecniqué, como horizonte histórico en el devenir de estos tiempos. La metodología estuvo regulada por el proceso hermenéutico-dialéctico: sentido, fusión de horizontes y comprensión. La interceptación permitió establecer que la universidad (latinoamericana) ha avanzado en los estudios científicos de orden positivista y, a la vez, los estudios de orden social se encuentras diseminados en diversos campos
Efecto antimicótico in vitro del aceite esencial de Origanum vulgare (orégano) sobre Candida albicans ATCC ® 10231™
No full textObjetive: to evaluate the antifungal effect of Origanum vulgare (oregano) essential oil against Candida albicans ATCC® 10231™. Methods: Ninety Petri dishes were inoculated with Saboraud agar and distributed into six work groups (100%, 75%, 50%, and 25% essential oil, a negative control with dimethyl sulfoxide, and a positive control with nystatin). Each group had 15 replicates selected by simple random sampling. The Kirby-Bauer technique was applied, placing a paper disc impregnated with the essential oil in the center of each plate and incubating the plates at 37°C. Inhibition halo measurements were taken at 24 and 48 hours. Statistical analysis was performed using the non-parametric Kruskal Wallis and Wilcoxon tests, using SPSS 25, with a confidence level of 95%. Results: showed that Origanum vulgare essential oil exhibited a significant antifungal effect, significantly superior to that of nystatin at all concentrations tested, both at 24 and 48 hours. The 100% concentration showed the greatest inhibitory effect. However, at 48 hours, the inhibition zone of the 25% oil was considerably reduced, although it still retained a significant antifungal effect against Candida albicans ATCC® 10231™. Conclusion: that oregano oil does have an antifungal effect against Candida albicans.Objetivo: evaluar el efecto antimicótico del aceite esencial de Origanum vulgare (orégano) frente a Candida albicans ATCC® 10231™. Métodos: se trabajó con 90 placas Petri con agar Saboraud e inoculadas con Candida albicans, distribuidas en 6 grupos de trabajo ( el aceite esencial al 100%, 75%,50%,25%, un control negativo con dimetilsulfóxido y un control positivo con nistatina); cada grupo contó con 15 repeticiones seleccionadas mediante muestreo aletaorio simple. Se aplicó la técnica de Kirby-Bauer, colocando en cada placa un disco de papel impregnado con el aceite esencial en el centro, y se incubaron a 37 °C; las mediciones de los halos de inhibición se realizaron a las 24 y 48 horas. El análisis estadístico se realizó con las pruebas no paramétrica de Kruskal Wallis y Wilcoxon, utilizando SPSS 25, con un nivel de confianza al 95%. Resultados: evidenciaron que el aceite esencial de Origanum vulgare presentó un alto efecto antimicótico, siendo significativamente superior a la de la nistatina en todas las concentraciones evaluadas, tanto a las 24 como a las 48 horas. La concentración al 100 % mostró el mayor efecto inhibitorio. No obstante, a las 48 horas, el halo de inhibición del aceite al 25 % se redujo considerablemente, aunque aún conservó un efecto antimicótico apreciable sobre Candida albicans ATCC® 10231™. Conclusión: el aceite de orégano si presenta efecto antimicótico frente al Candida albicans
Tuberculosis multisistémica en paciente inmunocompetente con afectación ganglionar y pleuropulmonar: Reporte de caso
No full textLa tuberculosis (TB) multisistémica, frecuentemente debido a la diseminación de Mycobacterium tuberculosis por vía linfohematógena durante la infección primaria y postprimaria, es una enfermedad rara en pacientes inmunocompetentes. Presentamos el caso de una paciente femenina de 29 años con diagnóstico de TB ganglionar en tratamiento que acude al servicio de emergencia del Hospital Regional Docente de Trujillo (HRDT) por presentar sintomatología compatible con TB pulmonar y pleural. El objetivo de este artículo es presentar el caso por su inusual evolución y exámenes de laboratorio que demuestran inmunocompetencia de la paciente a pesar de la presentación clínica
Tasas y causas de rechazo en donantes de sangre de un centro de hemoterapia peruano durante la pandemia COVID-19
No full textObjetive: To determine the proportion, relationship and main causes of rejection of blood donors in the Hemotherapy Center of the Regional Teaching Hospital of Trujillo in the context of the COVID-19 pandemic 2020 to 2021. Methods: Research descriptive, retrospective, cross-sectional, in donors who attended the Hemotherapy Center of the Regional Teaching Hospital of Trujillo in the context of the COVID-19 pandemic between March 2020 and March 2021. Data collection was carried out using the care records of the blood bank service applicants. Results: A predominance of the male sex (74.4%), Rh + blood type (97.1%) and blood group “O” (79.4%) was found. Furthermore, the majority of donors had an average age of 33 years, were considered suitable to donate (69.6%), were new donors (66.1%) and replacement donors (95.0%). Likewise, the main causes of refusal to donate blood were a low hematocrit level (14.3%), risk behavior (12.1% and having some respiratory pathology (11.9%). In the same way, the multivariate analysis confirms that the hematocrit, Rh type and age are associated with the highest frequency of rejection. Conclusion: Hematocrit, Rh type and age were associated with the highest frequency of rejection in donors who attended the Hemotherapy center of the Regional Teaching Hospital of Trujillo in the context of the COVID-19 pandemic 2020 to 2021.Objetivo: Determinar la proporción, las causas y los factores asociados al rechazo de donantes de sangre en el Centro de Hemoterapia del Hospital Regional Docente de Trujillo en el contexto de la pandemia por COVID-19 (marzo 2020 - marzo 2021). Métodos: Estudio observacional, transversal y analítico. Se incluyeron 2896 postulantes a donación de sangre entre 18 y 60 años. Se recolectaron datos sociodemográficos y clínicos. Se realizó un análisis descriptivo y bivariado (Chi2, U de Mann-Whitney) y se aplicó un modelo de regresión log-binomial para estimar razones de prevalencia ajustadas (RPa). Nivel de significancia: p<0.05. Resultados: El 30.4% de los postulantes fueron rechazados. Las principales causas de rechazo fueron hematocrito bajo (14.3%), conducta de riesgo (12.1%) y patologías respiratorias (11.9%). En el modelo ajustado, el grupo sanguíneo B (RPa=1.68; IC95%: 1.32-2.13) y hematocrito bajo (RPa=1.81; IC95%: 1.42-2.32) se asociaron significativamente con mayor prevalencia de rechazo. No se halló asociación significativa con la edad ni el tipo Rh. Conclusión: La prevalencia de rechazo fue alta. Los factores asociados fueron hematocrito bajo y grupo sanguíneo B. Se recomienda fortalecer la evaluación pre-donación y fomentar la donación voluntaria con mejor selección de candidatos
Variabilidad de suelos en una toposecuencia del Valle de Monzón, selva alta del Perú: Morfología, propiedades y clasificación
No full textKnowing the taxonomy, mineralogy, and properties of soils is essential to understand their genesis, functionality, and potential use, and it is fundamental for implementing land-use planning and to characterize soil use management systems. The objective of this study was to describe and correlate the taxonomic characteristics (Soil Taxonomy and World Soil Classification), morphological, physicochemical, and mineralogical characteristics of soils in relation to their physiographic position, based on 15 profiles of a toposequence obtaining 81 horizons. It was verified that soil variability was linked to relief; likewise, soil orders ranging from Entisols to Inceptisols were identified according to the Soil Taxonomy classification. While through the World Soil classification, the groups: Fluvisols, Regosols, Umbrisols, Cambisols, and Luvisols were identified. Morphologically, the fluvial soils were characterized by presenting Ap surface horizons, verifying the absence of subsurface horizons, denoting that they are young soils. In the physical attributes, there were sandy textures in fluvial soils and clayey textures in residual soils. Greater fertility was evidenced in lower terraces, and as the relief rises, fertility decreases. There was a correlation between physical and chemical attributes; in this sense, fertility depends to some extent on physical characteristics. The mineralogical analysis, using X-ray diffraction and X-ray fluorescence, revealed a predominance of 2:1 minerals in fluvial soils, associated with SiO₂/R₂O₃ molar ratios > 2; whereas in residual soils, 1:1 minerals predominated, with ratios < 2. Finally, fertility decreased according to soil origin: highest in fluvial soils, intermediate in alluvial soils, and lowest in residual soils.Conocer la taxonomía, mineralogía y propiedades de los suelos es fundamental para entender su génesis, funcionalidad y potencial de uso, siendo necesario para implementar planes de ordenamiento territorial y caracterizar sistemas de manejo de uso de suelo. El objetivo de estudio fue describir y correlacionar las características taxonómicas (Soil Taxonomy y la Base Referencial Mundial del Recurso suelo “WRB”), morfológicas, fisicoquímicas y mineralógicas de los suelos en relación con su posición fisiográfica, en base a 15 perfiles de una toposecuencia obteniéndose 81 horizontes. Se verificó que la variabilidad edáfica estaba vinculada al relieve; asimismo, se identificaron ordenes desde Entisols a Inceptisols con la clasificación Soil Taxonomy, ya mediante la WRB se identificaron los grupos: Fluvisols, Regosols, Umbrisols, Cambisols a Luvisols. Morfológicamente, los suelos fluviales se caracterizaron por presentar horizontes superficiales Ap, verificándose ausencia de horizontes subsuperficiales denotando ser suelos jóvenes. En los atributos físicos hubo texturas arenosas en suelos fluviales a arcillosas en residuales. Se evidencio mayor fertilidad en terrazas bajas y conforme se asciende en el relieve la fertilidad disminuye. Hubo correlación entre los atributos físicos y químicos, en tal sentido la fertilidad depende en cierta medida de las características físicas. El análisis mineralógico, mediante Difracción y Fluorescencia de Rayos X, reveló mayor predominio de minerales 2:1 en suelos fluviales, asociados a relaciones molares SiO₂/R₂O₃ > a 2; mientras en suelos residuales dominaron minerales 1:1 con relaciones < a 2. Finalmente, la fertilidad disminuyó conforme su origen: mayor en fluviales, intermedia en aluviales y menor en residuales
El compostaje en agroecología: Efectos sobre la estructura del suelo, la disponibilidad de nutrientes y los microorganismos beneficiosos
No full textComposting is a key strategy in agroecology that improves soil fertility without causing negative environmental effects. Unlike synthetic fertilizers, compost promotes soil regeneration by increasing its organic matter content, enhancing its structure, and stimulating beneficial microbial activity. This review article examines how composting optimizes the physical, chemical, and biological properties of the soil, increasing its water retention capacity, the availability of essential nutrients such as nitrogen, phosphorus, and potassium, and strengthening crop resilience against diseases and environmental stress. Different composting methods, such as vermicomposting, windrow composting, and Bokashi, are compared, demonstrating that regardless of the method used, compost does not contribute to soil degradation but instead enriches it in a sustainable manner. Additionally, the role of key microorganisms in nutrient mineralization and the improvement of the soil microbiome is highlighted, ensuring a balanced and slow-release supply for plants. Finally, innovative strategies to optimize compost quality using microbial inoculants and natural amendments are discussed, consolidating their role as a sustainable alternative for efficient and environmentally responsible agricultural production.El compostaje es una estrategia clave en la agroecología, que mejora la fertilidad del suelo sin generar efectos negativos en el ambiente. A diferencia de los fertilizantes sintéticos, el compost promueve la regeneración del suelo al incrementar su contenido de materia orgánica, mejorar su estructura y estimular la actividad microbiana beneficiosa. Este artículo de revisión analiza cómo el compostaje optimiza las propiedades físicas, químicas y biológicas del suelo, aumentando su capacidad de retención de agua, la disponibilidad de nutrientes esenciales como nitrógeno, fósforo y potasio, y fortaleciendo la resiliencia de los cultivos frente a enfermedades y estrés ambiental. Se comparan distintos métodos de compostaje, como el vermicompostaje, el compostaje en hileras y el Bokashi, evidenciando que, independientemente del método utilizado, el compost no contribuye a la degradación del suelo, sino que lo enriquece de manera sostenible. Además, se destaca el papel de los microorganismos clave en la mineralización de nutrientes y la mejora del microbioma del suelo, asegurando un suministro equilibrado y de liberación lenta para las plantas. Finalmente, se discuten estrategias innovadoras para optimizar la calidad del compost mediante el uso de inóculos microbianos y enmiendas naturales, consolidando su papel como alternativa sostenible para una producción agrícola eficiente y ambientalmente responsable
Physicochemical and sensory characteristics of ferrous sulfate and ferric pyrophosphate for fresh cheese fortification
No full textThis study evaluated the effects of adding microencapsulated ferrous sulfate (MFS) and ferric pyrophosphate (FPP) to a fresh cheese product. Five treatments were manufactured: a control (CTRL) and cheeses fortified with MFS or FPP at 90 mg Fe/kg (MFS1, FPP1) and 300 mg Fe/kg (MFS2, FPP2). The physicochemical characteristics (dry matter, moisture, mineral content, and color) and sensory profiles were analyzed. Results indicated that fortification decreased moisture content and increased dry matter. The MFS2 treatment showed the highest iron content (225.05 mg/kg) without compromising calcium levels. Significant color changes were observed only in the a* (redness) component of the FPP2 treatment. Sensory analysis revealed that the CTRL and FPP2 treatments were most liked, while the MFS2 treatment was least liked due to a pronounced metallic and rancid flavor. In conclusion, the type and concentration of the iron compound significantly influenced the cheese's final characteristics, whereas storage time had a minimal effect. FPP is a more suitable fortificant than MFS for maintaining the sensory quality of fresh cheese