198 research outputs found

    Interstitial cells of Cajal and enteric nervous system in gastrointestinal and neurological pathology. Relation to oxidative stress

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    The enteric nervous system (ENS) is organized into two plexuses—submucosal and myenteric—which regulate smooth muscle contraction, secretion, and blood flow along the gastrointestinal tract under the influence of the rest of the autonomic nervous system (ANS). Interstitial cells of Cajal (ICCs) are mainly located in the submucosa between the two muscle layers and at the intramuscular level. They communicate with neurons of the enteric nerve plexuses and smooth muscle fibers and generate slow waves that contribute to the control of gastrointestinal motility. They are also involved in enteric neurotransmission and exhibit mechanoreceptor activity. A close relationship appears to exist between oxidative stress and gastrointestinal diseases, in which ICCs can play a prominent role. Thus, gastrointestinal motility disorders in patients with neurological diseases may have a common ENS and central nervous system (CNS) nexus. In fact, the deleterious effects of free radicals could affect the fine interactions between ICCs and the ENS, as well as between the ENS and the CNS. In this review, we discuss possible disturbances in enteric neurotransmission and ICC function that may cause anomalous motility in the gut

    Short film production in educational contexts: exploring the methodology of the Olhar pela Lente project in Portugal

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    Cinema’s pedagogical essence nurtures a variety of educational strategies. Beyond serving as a support to other areas of knowledge or as the subject of artistic analysis, it also provides students with a means to give – freely and significantly – voice to their own concerns and interests. Short film production in schools can offer a process for young people to deal with personal and social challenges, fostering a closer connection between them and their community and environment. Schools are natural habitats for this encounter – a place where film production can generate significant educational and cultural resonance. This paper reflects on the didactic potential of short film production in schools – as a key to fulfil formal and non-formal pedagogical goals – through the presentation and analysis of a recently implemented methodology for education through film: Olhar pela Lente, a project developed in Portugal during 2018.info:eu-repo/semantics/publishedVersio

    Holographic flavor on the Higgs branch

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    In this paper we study the holographic dual, in several spacetime dimensions, of the Higgs branch of gauge theories with fundamental matter. These theories contain defects of various codimensionalities, where the matter fields are located. In the holographic description the matter is added by considering flavor brane probes in the supergravity backgrounds generated by color branes, while the Higgs branch is obtained when the color and flavor branes recombine with each other. We show that, generically, the holographic dual of the Higgs phase is realized by means of the addition of extra flux on the flavor branes and by choosing their appropriate embedding in the background geometry. This suggests a dielectric interpretation in terms of the color branes, whose vacuum solutions precisely match the F- and D-flatness conditions obtained on the field theory side. We further compute the meson mass spectra in several cases and show that when the defect added has codimension greater than zero it becomes continuous and gapless.Comment: 59 pages, 1 figure;v2: references adde

    Nueva metodología de evaluación del Holter basada en los sistemas dinámicos y la geometría fractal: confirmación de su aplicabilidad a nivel clínico

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    Introducción: La teoría de sistemas dinámicos establece medidas cuantitativas de evolución de los sistemas mediante la construcción de atractores. Medidas de ocupación espacial de atractores cardiacos en el espacio fractal de Box Counting diferenciaron normalidad y enfermedad crónica de enfermedad aguda. Objetivo: Aplicar la metodología desarrollada para evaluar matemáticamente el estado cardiaco de Holter con diferentes patologías, confirmando la aplicabilidad de esta metodología para la detección de dinámicas agudas mediante medidas de concordancia estadística respecto al Gold Standard. Metodología: Se analizaron 170 Holter, incluyendo normales, crónicos y en estado agudo. Se construyeron simulaciones de la totalidad de la dinámica basada en número de latidos y frecuencia mínima y máxima cada hora durante 21 horas, para construir atractores en el espacio de fases. Se calculó la dimensión fractal de los atractores evaluando su ocupación espacial en el espacio de Box Counting, estableciendo cuáles corresponden a normalidad y enfermedad aguda de acuerdo con resultados matemáticos previos. Se comparó el diagnóstico matemático con el diagnóstico convencional del Holter, tomado como Gold Standard, estableciendo valores de sensibilidad, especificidad y coeficiente Kappa. Resultados: La dimensión fractal no logró evidenciar diferencias cuantitativas mientras que la metodología detectó en todos los casos dinámicas normales y en estado agudo independientemente de la patología, logrando valores de sensibilidad, especificidad, valor predictivo positivo y negativo de 100%, y coeficiente Kappa de 1. Conclusiones: Se confirmó la capacidad de la metodología físico-matemática para detectar dinámicas agudas independientemente de la patología asociada, confirmando una auto-organización acausal de la dinámica del sistema cuya evaluación permite establecer medidas de aplicabilidad clínica.  Introduction: Dynamic systems theory provides quantitative measures of evolution of systems by building attractors. Spatial occupation measures of cardiac attractors in fractal Box Counting space differentiated normality and chronic disease from acute illness. Objective: To apply the developed methodology to evaluate mathematically the cardiac status of Holter with different pathologies, confirming the applicability of this methodology for the detection of acute dynamic by statistical measures of agreement regarding the Gold Standard. Methodology: 170 Holter, including normal, chronic and in acute states were evaluated. Simulations were constructed the entire dynamic based on the number of beats and the minimum and maximum frequencies every hour for 21 hours, to build attractors in the phase space. The fractal dimension of attractors is calculated, evaluating the spatial occupation in the Box Counting space, establishing which corresponds to normal setting and acute disease in accordance with previous mathematical results. Mathematical diagnosis was compared with conventional diagnostic Holter, taken as the Gold Standard, setting sensitivity, specificity, positive and negative predictive value and Kappa coefficient. Results: The fractal dimension failed to show quantitative differences while the methodology detected in all cases normal dynamics and acute state independently of the disease, achieving sensitivity, specificity, positive and negative predictive value of 100% and a Kappa 1. Conclusions: the ability of the physical-mathematical methodology to detect acute dynamic regardless of the associated pathology was confirmed, as well as an acausal self-organization of the system dynamics, which allows for assessment of clinical applicability measures

    Genotype by environment interaction and productive potential of 25 starch maize assessed at the Tayacaja Province, Peru

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    La interacción genotipo por ambiente (IGA) representa el principal obstáculo en la selección de los genotipos promisorios para diversos ambientes. El objetivo de esta investigación fue evaluar la IGA y el potencial productivo de 25 variedades de maíz amiláceo, utilizando el modelo de efectos principales aditivos e interacción multiplicativa (AMMI). Se utilizó la información generada en cinco ensayos establecidos en diferentes localidades de la provincia de Tayacaja, Huancavelica, Perú, en el ciclo del cultivo 2018–2019, bajo un diseño alfa látice 5x5, con tres repeticiones y unidades experimentales de dos hileras de 4 m de longitud, con arreglos espaciales de 0,80 m entre hileras y 0,20 m entre puntos de siembra. El potencial productivo de los cultivares se midió a través del rendimiento de grano, ajustado a 15 % de humedad. Definida la IGA, se realizó el análisis multivariado, para obtener los valores singulares de los primeros términos significativos del modelo para genotipos y ambientes. La IGA resultó altamente significativa y explicó alrededor del 14 % de la variación fenotípica del rendimiento, mostrando algunas variedades con adaptación específica y otras con amplia adaptación a los ambientes de prueba. El modelo AMMI explicó alrededor del 96 % de la variación debida a la IGA, observándose que sólo los dos primeros ejes concentraron cerca del 85 % de dicha variación. Las variedades locales Chullpi-Q, Carhuay-P, Astilla Blanca-Cusqueado, Astilla Blanca-DH, Cusqueado-P y Astilla Blanca-Astilla Amarilla mostraron el mejor potencial productivo, pero sólo las tres primeras fueron estables a través de los ambientes de evaluación

    COVID-19 : Age, Interleukin-6, C-reactive protein, and lymphocytes as key clues from a multicentre retrospective study

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    Background: The SARS-CoV-2 infection has widely spread to become the greatest public health challenge to date, the COVID-19 pandemic. Different fatality rates among countries are probably due to non-standardized records being carried out by local health authorities. The Spanish case-fatality rate is 11.22%, far higher than those reported in Asia or by other European countries. A multicentre retrospective study of demographic, clinical, laboratory and immunological features of 584 Spanish COVID-19 hospitalized patients and their outcomes was performed. The use of renin-angiotensin system blockers was also analysed as a risk factor. Results: In this study, 27.4% of cases presented a mild course, 42.1% a moderate one and for 30.5% of cases, the course was severe. Ages ranged from 18 to 98 (average 63). Almost 60 % (59.8%) of patients were male. Interleukin 6 was higher as severity increased. On the other hand, CD8 lymphocyte count was significantly lower as severity grew and subpopulations CD4, CD8, CD19, and NK showed concordant lowering trends. Severity-related natural killer percent descents were evidenced just within aged cases. A significant severity-related decrease of CD4 lymphocytes was found in males. The use of angiotensin-converting enzyme inhibitors was associated with a better prognosis. The angiotensin II receptor blocker use was associated with a more severe course. Conclusions: Age and age-related comorbidities, such as dyslipidaemia, hypertension or diabetes, determined more frequent severe forms of the disease in this study than in previous literature cohorts. Our cases are older than those so far reported and the clinical course of the disease is found to be impaired by age. Immunosenescence might be therefore a suitable explanation for the hampering of immune system effectors. The adaptive immunity would become exhausted and a strong but ineffective and almost deleterious innate response would account for COVID-19 severity. Angiotensin-converting enzyme inhibitors used by hypertensive patients have a protective effect in regards to COVID-19 severity in our series. Conversely, patients on angiotensin II receptor blockers showed a severer disease

    Future research directions on the "elusive" white shark

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    White sharks, Carcharodon carcharias, are often described as elusive, with little information available due to the logistical difficulties of studying large marine predators that make long-distance migrations across ocean basins. Increased understanding of aggregation patterns, combined with recent advances in technology have, however, facilitated a new breadth of studies revealing fresh insights into the biology and ecology of white sharks. Although we may no longer be able to refer to the white shark as a little-known, elusive species, there remain numerous key questions that warrant investigation and research focus. Although white sharks have separate populations, they seemingly share similar biological and ecological traits across their global distribution. Yet, white shark’s behavior and migratory patterns can widely differ, which makes formalizing similarities across its distribution challenging. Prioritization of research questions is important to maximize limited resources because white sharks are naturally low in abundance and play important regulatory roles in the ecosystem. Here, we consulted 43 white shark experts to identify these issues. The questions listed and developed here provide a global road map for future research on white sharks to advance progress toward key goals that are informed by the needs of the research community and resource managers
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