A note on the geodesic deviation equation for null geodesics in the Schwarzschild black-hole

We use the Hamiltonian formulation of the geodesic equation in the Schwarzschild space-time so as to get the variational equation as the counterpart of the Jacobi equation in this approach. In this context we are able to apply the Morales-Ramis theorem to link the integrability of the geodesic equation to the integrability, in the sense of differential Galois theory, of the variational equation. This link is strong enough to hold even on geodesics for which the usual conserved quantities fail to be independent, as is the case of circular geodesics. We show explicitly the particular cases of some null geodesics and their variational equations.Comment: 12 page

Análisis crítico del discurso del presidente de El Salvador Nayib Bukele en tuits emitidos desde el 28 de febrero hasta el 16 de mayo de 2021

Los medios de comunicación son canales o instrumentos para informar a la sociedad sobre hechos y acontecimientos políticos, sociales, económicos, culturales, nacionales e internacionales; y, por su parte, las redes sociales ejecutan en Internet este rol comunicativo con alcance global, y es Twitter una de las más preferidas por políticos y mandatarios, funciona bajo la dinámica del microblogging, con las ventajas de los blogs y la inmediatez de la mensajería instantánea; esta interesante forma de comunicación ha permitido poner en contacto en tiempo real a las personas por medio de mensajes de texto también denominados “tuits”. Twitter rápidamente se volvió un símbolo de la administración pública del presidente de El Salvador Nayib Bukele, en un momento en que el movimiento y partido político Nuevas Ideas alcanza mayoría en la Asamblea Legislativa, dando a este mandato control pleno de los órganos Ejecutivo, Legislativo y Judicial. Por ello, el propósito fundamental de esta investigación es analizar los tuits del presidente Bukele, como instrumentos de persuasión, legitimación de sus acciones y deslegitimación de las acciones de sus oponentes, tanto político como social. Este estudio es una herramienta de análisis e interpretación aplicable a cualquier otro discurso a través de cualquier otro medio. Palabras clave: Análisis ; Discurso ; Crítico ; Lingüística ; Teun Van Dijk ; Twitter ; Tweet ; tuit ; Presidente ; Nayib ; Bukele ; Comunicación ; Redes sociales ; Gobierno ; El Salvador ; Centroamérica ; Legitimación ; Deslegitimación ; Investigación cualitativa

Evaluation of the management of marine protected areas. Comparative study in Costa Rica

Costa Rica is one of the most biodiverse countries in the world, and stands out for its commitment to conservation. Along its two coasts, it presents a great heterogeneity of ecosystems and social realities. Social factors, more than physical-natural factors, determine the success or failure of an MPA, so they must be urgently incorporated into all phases of MPA management. The objective of this work is to analyze the management of three marine protected areas, to establish improvements. These areas are Santa Rosa National Park, Marino Ballena National Park and Cahuita National Park. The methodology used assesses 26 indicators grouped into 4 key factotres: management body, planning subprocess, public participation, and implementation subprocess. The results of this evaluation are 5 possible scenarios. These scenarios have been termed (from the ideal situation to the least favourable): proactive (1), learning (2), interactive (3), centralized (4) and formal (5) management. The results of this study show that both Santa Rosa and Cahuita present a proactive scenario (1), with high citizen participation, although in practice the way the two MPAs are managed is very different. Marino Ballena, on the other hand, is in scenario 5 (formal), and a series of measures are presented that can move it towards scenario 2 (learning). In general, MPA management in Costa Rica tends to be adaptive, with high public participation, as determined by its public policies. However, the existence of a public policy favors but does not guarantee success in MPA management, as can be seen in the difference in results. Therefore, the periodic evaluation of its management, allowing for feedback, is essential

Concordancia entre los modelos de SCORE y Framingham y las ecuaciones AHA/ACC como evaluadores de riesgo cardiovascular

ResumenObjetivoDiferentes modelos de evaluación de riesgo cardiovascular están actualmente en uso en Colombia. El objetivo de este estudio es analizar la concordancia entre las ecuaciones AHA/ACC 2013, SCORE y Framingham ajustado, así como el impacto de usar una u otra en la cantidad de pacientes clasificados como de alto riesgo y en la cantidad de pacientes que requerirían manejo farmacológico.MétodosSe evaluaron 800 pacientes entre 40 y 74 años, de la clínica de prevención primaria del Hospital militar Central en Bogotá (Colombia), libres de eventos cardiovasculares. Se estimaron el riesgo a 10 años de enfermedad arterioesclerótica cardiovascular según las ecuaciones propuestas por las guías AHA/ACC 2013, el riesgo de muerte cardiovascular según la función SCORE de la guía europea y el riesgo coronario según la función de Framingham ajustada, recomendada por la guía colombiana. Se consideró como indicación de manejo farmacológico un cálculo de riesgo AHA/ACC o Framingham ajustado>7,5%. Un riesgo de Framingham>20% o SCORE>5% definía el riesgo alto.ResultadosSegún el Framingham había un 5,9% de pacientes de alto riesgo, según las ecuaciones de SCORE para países de bajo riesgo un 18,7% y según las ecuaciones de SCORE para países de alto riesgo, un 31,2%. El coeficiente Kappa mostró baja concordancia entre Framingham ajustado y cada una de las ecuaciones de SCORE (0,28 y 0,22 respectivamente). Según las recomendaciones de la guía AHA/ACC, el tratamiento hipolipemiante estaría indicado en un 40,8% de los pacientes, frente a un 50,6% según la guía colombiana (Framingham ajustado). El coeficiente kappa fue de 0,5735.ConclusionesEn la actualidad existe pobre acuerdo entre las diferentes escalas de evaluación del riesgo cardiovascular usadas en Colombia, hecho que conlleva incertidumbre para la toma de decisiones terapéuticas. Los datos de este estudio demuestran la necesidad de validar los modelos de SCORE y AHA/ACC en Colombia y Latinoamérica.AbstractMotivationIn Colombia, different models of cardiovascular risk assessment are currently being used. The motivation of this study is to analyse the concordance between the ACC/AHA 2013 equation, SCORE and adjusted Framingham, as well as the impact of using one or another in the amount of patients classified as high risk and the amount of patients requiring pharmacological management.Methods800 patients between 40 and 74 years old were assessed, from the primary prevention clinic of the Hospital Militar Central in Bogotá (Colombia), who were free of cardiovascular events. 10-year risk for atherosclerotic vascular disease was estimated according to the equations proposed by ACC/AHA 2013 guides, the risk of cardiovascular death according to the SCORE function of the European guide and the coronary risk according to the adjusted Framingham function recommended by the Colombian guide. The indication of pharmacological management was considered with an ACC/AHA or adjusted Framingham risk of>7.5%. A >20% Framingham or a >5% SCORE risk were considered high risk.ResultsAccording to Framingham there was a 5.9% of high-risk patients, according to SCORE equations for low-risk countries an 18.7% and according to SCORE equations for high-risk countries, a 31.2%. The Kappa coefficient showed a low concordance between adjusted Framingham and each of the SCORE equations (0.28 and 0.22 respectively). According to the ACC/AHA guide recommendations, hypolipidemic treatment would be indicated in 40.8% of patients, versus a 50.6% following the Colombian guide indications (adjusted Framingham). Kappa coefficient was 0.5735.ConclusionsNowadays there is a poor agreement between the different cardiovascular risk assessment scales used in Colombia, thus generating uncertainty when it comes to making therapeutic choices. Data from this study show the need to validate the validate the SCORE and ACC/AHA models in Colombia and Latin America

Identification of reference genes for real-time PCR cytokine gene expression studies in sheep experimentally infected with Fasciola hepatica

The aim of this study was to validate reference genes for gene normalisation using qRT-PCR in hepatic lymph nodes (HLN) and livers from sheep infected with Fasciola hepatica during early and late stages of infection. To this end, a comprehensive statistical approach (RefFinder) encompassing four different methods of analysis (geNorm, BestKeeper, ΔCt method and NormFinder) was used to validate ten candidate reference genes. Stability analysis of gene expression followed by pairwise variation (Vn/Vn + 1) analysis revealed that PGK1, HSP90AA1 and GYPC were the most stable reference genes and suitable for qRT-PCR normalisation in both HLN and liver tissues. These three genes were validated against FoxP3, IL-10, TGF-β, TNF-α and IL-1β genes in the HLN tissue of sheep vaccinated with Cathepsin L1 from F. hepatica and unvaccinated infected and uninfected controls during early stages of infection. In the liver, the three reference genes were validated against TNF-α and IL-1β during chronic stages of infection with F. hepatica and in uninfected controls. Our study is the first to evaluate and validate sheep reference genes in order to provide tools for monitoring cytokines in Fasciola hepatica infected sheep target organs. Our results present an approach to elucidate the role of different cytokines in F. hepatica vaccinated and infected shee

Th1/Th2 balance in the liver and hepatic lymph nodes of vaccinated and unvaccinated sheep during acute stages of infection with Fasciola hepatica

The expression of IFNγ and IL4 was quantified using q-PCR in the liver and hepatic lymph nodes (HLN) of sheep during early stages of infection with Fasciola hepatica (1, 3, 9 and 18days post-infection, dpi). A group of animals (Group 1) were vaccinated with Fasciola hepatica recombinant cathepsin L1 (FhCL1) in montanide 70 VG prior to infection, a second group (group 2) was used as infected control and a third (group 3) was used as uninfected control. To study vaccine efficacy three additional groups were sacrificed 19 weeks post-infection (group 4 immunized with CL1, group 5 with the adjuvant and group 6 was used as infected control). The vaccinated group did not show significant fluke reduction compared to the adjuvant group and infected control group. IL4 expression was observed to increase at 9 dpi and was further elevated at 18 dpi in the liver and HLN of vaccinated and infected control groups compared to the uninfected group. IFNγ expression exhibited different dynamics in the liver and HLN compared to IL4; thus, in the liver this cytokine increased at 9 dpi in the vaccinated and at 18 dpi in vaccinated and infected control groups, while in the HLN it decreased gradually and significantly from 1 dpi onwards. These results suggest that a marked Th2 polarization is present from 9 dpi in HLN and from 18 dpi in the liver. The increase of IFNγ in the liver may correspond with tissue damage response with granuloma formation. The FhCL1 vaccine did not alter the Th1/Th2 balance when compared to unvaccinated and infected sheep. The study of IFNγ and IL4 in the various tissue compartments in sheep could facilitate selection of new adjuvants inducing a strong Th1 response for a more rationale vaccine formulation.This work was supported by EU grants (FPVII-265862-PARAVAC, H2020-635408-PARAGONE) and National grant (AGL2015-67023-C2-1-R)

Conversión de tuberculina en trabajadores del Hospital Universitario San Ignacio y asociación con características demográficas y laborales

Objetivos: Establecer la prevalencia de positividad, la tasa de conversión de la tuberculina en trabajadores de nuestro hospital y describir las características demográficas y laborales asociadas a esto.Materiales y Métodos Estudio observacional descriptivo en una cohorte de trabajadores del hospital a los que se les realizó la prueba de tuberculina. Se definió la positividad de la prueba de tuberculina como un resultado mayor o igual a 10 mm y la conversión como un aumento de 6 o 10 mm con respecto a la prueba inicial.Resultados Se encontró una prevalencia de 23,7 % y una incidencia de conversión de 13,6 % para el punto de corte mayor de 10 mm y 23 % para el punto de corte de 6 mm.  La edad de los sujetos estuvo relacionada a conversión, mientras que no se encontró relación con la ocupación.Conclusión La probabilidad de transmisión de la tuberculosis en trabajadores del hospital es mayor al de la población general. Deben ser implementadas medidas de promoción y prevención para disminuir la transmisión e incrementar el conocimiento de la tuberculosis asociada al cuidado de la salud en los trabajadores

Angiogenin secretion from hepatoma cells activates hepatic stellate cells to amplify a self-sustained cycle promoting liver cancer

Hepatocellular carcinoma (HCC) frequently develops in a pro-inflammatory and pro-fibrogenic environment with hepatic stellate cells (HSCs) remodeling the extracellular matrix composition. Molecules secreted by liver tumors contributing to HSC activation and peritumoral stromal transformation remain to be fully identified. Here we show that conditioned medium from HCC cell lines, Hep3B and HepG2, induced primary mouse HSCs transdifferentiation, characterized by profibrotic properties and collagen modification, with similar results seen in the human HSC cell line LX2. Moreover, tumor growth was enhanced by coinjection of HepG2/LX2 cells in a xenograft murine model, supporting a HCC-HSC crosstalk in liver tumor progression. Protein microarray secretome analyses revealed angiogenin as the most robust and selective protein released by HCC compared to LX2 secreted molecules. In fact, recombinant angiogenin induced in vitro HSC activation requiring its nuclear translocation and rRNA transcriptional stimulation. Moreover, angiogenin antagonism by blocking antibodies or angiogenin inhibitor neomycin decreased in vitro HSC activation by conditioned media or recombinant angiogenin. Finally, neomycin administration reduced tumor growth of HepG2-LX2 cells coinjected in mice. In conclusion, angiogenin secretion by HCCs favors tumor development by inducing HSC activation and ECM remodeling. These findings indicate that targeting angiogenin signaling may be of potential relevance in HCC managementThis study was funded by grants from the Instituto de Salud Carlos III (FIS PI12/00110, PI09/00056 to A.M., FIS PI10/02114, PI13/00374 to M.M., PI12/01265 to J.C. and PI11/0325 to J.F.C.), Ministerio de Economía y Competitividad (SAF 2012/34831 to J.F.C. and SAF2011-23031 to C.G.R.) and co-funded by FEDER (Fondo Europeo de Desarrollo Regional, Unión Europea. “Una manera de hacer Europa”); center grant P50-AA-11999 from Research Center for Liver and Pancreatic Diseases, US NIAAA to J.F.C.); Fundació la Marató de TV3 to J.F.C., Mutua Madrilea (AP103502012) to C.G.R., and by CIBERehd from the Instituto de Salud Carlos IIIPeer Reviewe

Proceso de evaluación y diseño del programa de salud ocupacional (Sistema de Gestión y Seguridad en el Trabajo) con énfasis en gestión del conocimiento de la empresa Lácteos Rovirenses

El presente documento contiene el proyecto de investigación denominado evaluación y diseño del programa de salud ocupacional (SG-SST) con énfasis en gestión del conocimiento de la empresa Lácteos Rovirenses de la ciudad de Málaga –Santander, el cual tiene como objetivo aplicar el modelo de gestión del conocimiento de Nonaka y Takeuchi.This document contains the research project for the evaluation and design of Occupational Health Program (SG-SST) with an emphasis on business knowledge management Rovirenses Dairy from the city of Málaga -Santander, which has as its objective to apply the knowledge management model of Nonaka and Takeuchi