Pasado, presente y futuro de la epidemiología. una perspectiva latinoamericana

Este artículo intenta contestar tres preguntas. Sobre el pasado: ¿Por qué no existió una epidemiología precolombina? Sobre el presente: ¿Cuáles son los orígenes de la epidemiología moderna, incluyendo sus raíces sudamericanas? Y sobre el futuro, escogí un título surrealista para enfatizar el hecho que estoy consciente de que es siempre delicado hacer predicciones: ¿Por qué fenómenos complejos son los “objetos oscuros del deseo” epidemiológico

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caminar la manzana... la calle era una red una cárcel la casa, peligro, blasfemias en las heridas viejas, ya no existes, no eres, peligrosa la casa, el auto con la fiera y un desgano el árbol del desnudo te da verguênza, lloras, duele el llanto y el ahora solo y gris hoy no tiene un mañana ni escalera de sol

PENGARUH LEVERAGE, PROFITABILITAS DAN UKURAN PERUSAHAAN TERHADAP NILAI PERUSAHAAN PADA PERUSAHAAN YANG TERDAFTAR DI BURSA EFEK INDONESIA

This research aims to know the influence of leverage, profitability and firm size against firm value either partially or simultaneously. The researcher wants to do research in manufacturing companies sub-sector food and beverage listed in Indonesia Stock Exchange period 2013-2017 using purposive sampling method. The dependent variable in this study is firm value and the independent variables are leverage, profitability and firm size. This method of analysis of this study uses multiple linear regression test using SPSS version 22.  The results of this study showed that leverage has significant effect partially with t-count > t-table or 3,029 > 1,68830 with significance value 0,005 < 0,05. Profitability has no significant effect partially with t count < t tabel or 0,020 < 1,68830 with significance value 0,984 > 0,05. Firm size has no significant effect partially with t count < t table or 0,480 < 1,68830 with significance value 0,634 > 0,05. Leverage, profitability, and firm size have significant effect simultaneously against firm value with F count > F table or 4,811 > 2,87 with significance value 0,006 < 0,05. Adjusted R Square showed 22,7% or 0,227 while the rest 77,3% is explained by others variables that not examined

The wound is always raw : searching, uncertainty, and collective support in the lives of mothers of disappeared people in contemporary Mexico

Mothers of disappeared people are caught at the intersection of two very difficult experiences: actively searching for their daughters and sons and facing the tremendous pain that comes from having a disappeared loved one. Drawing from ten in-depth interviews with mothers of disappeared people in contemporary Mexico, this thesis explores the impacts of both of these challenges and the ways that these mothers navigate them. In particular, uncertainty, the search for their daughters and sons, social isolation, and collective support emerged as key components of the experiences of this group of women. Their experiences highlight the traumatic nature of the uncertainty about the fate and whereabouts of their daughters and sons and the emotional and cognitive flexibility that allows them to simultaneously hold seemingly contradictory beliefs that go beyond the dichotomy of life and death. The State maintains and reproduces uncertainty through the legal-administrative stage of disappearance, rooted in a historically flawed, corrupt, and inefficient bureaucracy. In this way, the uncertainty that characterizes disappearance is not only an individually traumatizing event, but also becomes part of a complex and multidimensional expression of State violence. For many mothers, actively engaging in the search for their disappeared loved one is an important coping mechanism and a source of personal empowerment, but it also creates important challenges in their lives. Although many mothers experience social isolation in the aftermath of the disappearance of their daughters and sons, the various forms of legal-administrative, emotional, and material support that they access through involvement in collectives of relatives of disappeared people are important sources of strength and resilienceLatin American StudiesSocial Wor

Análise experimental da adição de fibras poliméricas nas propriedades mecânicas do concreto

A adição de fibras ao concreto é uma prática que busca reduzir o surgimento de fissuras e suas respectivasaberturas. Diversos tipos de fibras são utilizadas com esse fim como, por exemplo, as fibras de aço e as fibraspoliméricas. O presente trabalho tem como objetivo avaliar a influência da adição de fibras poliméricas naspropriedades mecânicas do concreto. Para isso foram realizados ensaios de resistência à compressão, módulode elasticidade, resistência à tração na flexão e avaliada a tenacidade de corpos de prova confeccionados comconcreto convencional (sem adição de fibras), concreto com adição de fibras de polipropileno e concreto comadição de fibras de polietileno de alto módulo. O comprimento das fibras poliméricas utilizadas é de 12 mm.Os resultados mostram que essas adições melhoram o desempenho do concreto para a resistência à tração etenacidade, porém não causaram variações significativas na resistência à compressão e no módulo de elasticidade

Investigating trophic ecology and dietary niche overlap among morphs of Lake Trout in Lake Superior

Four morphs of Lake Trout (Salvelinus namaycush, Walbaum 1792) have been identified in Lake Superior: leans, siscowets, humpers, and redfins. In this comprehensive study, the trophic ecology of Lake Trout morphs were characterized using stomach content, fatty acid, and stable isotope data. Stomach content results indicated a predominately piscivorous diet for leans, siscowets, and redfins, whereas humper diets were comprised of 50% fish and 50% Mysis by mass. Humper and siscowets were most similar in their dietary fatty acid profiles, whereas redfins had the most distinct dietary fatty acid profile. Results from stable isotope analysis revealed some among-morph differences along a pelagic-profundal consumption gradient (34S), but there were no significant differences in trophic position (15N) or basal carbon sources among morphs (13C). Using the recently developed nicheROVER software package, 4-dimensional trophic niches for each morph were quantified using stable isotope ratios (δ13C, δ15N, and δ34S) and fatty acid profiles (30 dietary fatty acids, condensed to one axis). Humpers had the largest 4-dimensional niche regions of all four morphs, and redfins had the smallest. Pairwise probability of overlap among morphs in these four-dimensional niche regions was determined to be < 50% in most cases. Overall, stomach content results indicate that humpers diets were more planktivorous than the other morphs, consistent with previous research. Results of the niche overlap analysis suggests some degree of generalist feeding for all morphs. Better characterization of seasonal variation in diet using tracers that reflect more recent feeding (e.g., fatty acids, stomach contents, and/or stable isotope analyses performed on tissues that turnover more quickly than muscle) are needed to further elucidate among-morph differences and similarities in diet and trophic ecology

Conception d'un simulateur in vitro pour l’étude des écoulements hémodynamiques sur fantôme d'aorte : application à la dissection aortique

Cardiovascular diseases (CVDs) including diseases of the heart and circulatory system are the leading cause of death in the European Union and accounted for about 37% of all deaths in 2017 (OCDE). Among CVDs, we can mention atherosclerosis, aneurysm and aortic dissection (AD). AD is a life-threatening pathology that develops when a tear occurs in the inner layer of the aorta. Blood surges into the tear and a secondary channel develops in between aorta layers. AD results in higher risks of rupture and malperfusion which makes of aortic dissection a pathology with a high mortality rate, difficult to detect in time and to treat in a lasting way. The mechanisms of its development are still poorly understood. Beyond purely biological concepts, fluid dynamics and biomechanics have contributed to AD understanding and pointed out some culprits such as alteration in stress patterns, flow distribution, and vortical flows. However, one of the main limitations in analyzing and understanding these mechanisms is flow visualization. {In vivo, routine traditional imaging that gives access to fluid velocities such as 4D-MRI or US-doppler suffers from low time and space resolutions. This is one reason why alternative techniques are developed with artificial circulation emulations to overcome human body observation limitations. The present work proposes an in vitro blood flow investigation. An aortic flow simulator was designed to emulate blood flow in aorta models (healthy and pathological) with biofidelic properties. The goal is to explore aorta hemodynamics and address the limitations encountered with in vivo traditional imaging as a complementary tool. Particle Image Velocimetry was implemented to accurately measure fluid velocities and compute quantities of interests in the context of disease mechanism understanding (shear rate, shear stress, vorticity, etc.). The bench is a circulatory mock loop that accurately recreates the cardiovascular system flowrate and pressure conditions. It accommodates healthy and pathological patient-specific aorta models – also called phantoms – and a panel of inflow conditions as a versatile tool. Phantoms with specific optical and mechanical features were manufactured with silicone injection and 3D printing to approach human aorta behavior. Different blood mimicking fluid were designed to investigate the impact of the more complex non-Newtonian representation of blood compared with the Newtonian simplification. Indeed, the shear-thinning behavior of blood is often neglected in the literature claiming that the Newtonian representation is equivalent. The present work shows that the Newtonian fluid flow in a healthy aorta phantom tends to underestimate shear stress and vortex displacement which could lead to misinterpretation of risky areas and pathological mechanisms. The non-Newtonian representation is, therefore, more adapted to investigate aorta hemodynamics. Finally, the experimental bench was developed in close connection with numerical simulations that focused on aided surgery for aortic dissection. Non-Newtonian flow visualizations were achieved with the in vitro simulator and PIV on patient-specific aortic dissection phantoms and compared with numerical results on the same models. It allowed confrontation and inter-validation of both model approaches. The developed aortic simulator is a powerful tool to better analyze and understand aortic hemodynamics to complement in vivo and in silico investigations.Les maladies cardiovasculaires (MCV), y compris les maladies cardiaques et circulatoires, sont la principale cause de décès dans l'Union Européenne et représentaient environ 37% des décès en 2017 (OCDE). Parmi les MCV on peut citer les pathologies artérielles telles que l’athérosclérose, les anévrysmes et la dissection aortique. Cette dernière se développe à la suite d’une déchirure dans la paroi interne de l’aorte. Le sang y pénètre et crée un chenal secondaire entre les couches de la paroi. Des risques de rupture et de malperfusion en découlent et font de la dissection aortique une pathologie à fort taux de mortalité, difficile à détecter et à traiter de façon durable. Les mécanismes de son développement sont encore mal connus. Au-delà des concepts purement biologiques, la dynamique des fluides et la biomécanique ont contribué à leur compréhension et ont mis en évidence certains liens avec l'altération des contraintes aux parois, la distribution des flux et les écoulements tourbillonnaires. Cependant, l'une des principales limites est la visualisation des écoulements. In vivo, l'imagerie médicale traditionnelle donnant accès à des écoulements telles que l'IRM-4D ou l'US-doppler souffre de faibles résolutions spatio-temporelles. Des techniques alternatives sont alors développées grâce à des émulateurs de circulation sanguine – in vitro ou in silico – pour surmonter les limites de l'observation directe in vivo.Ce travail propose une étude des flux sanguins in vitro. Un simulateur a été conçu pour reproduire les écoulements sanguins sur modèles d'aorte biofidèles (saines et pathologiques). L'objectif est d'explorer l'hémodynamique de l'aorte et de surmonter les limites rencontrées avec l'imagerie médicale traditionnelle comme outil complémentaire. La vélocimétrie par image de particules a été mise en œuvre pour mesurer avec précision les vitesses des fluides et calculer les quantités d'intérêt liées à la compréhension des mécanismes de la maladie (taux de cisaillement, contrainte de cisaillement, tourbillon, etc.). Le banc est un circuit hydraulique qui recrée avec précision les conditions de débit et de pression du système cardiovasculaire. Il s'adapte à des modèles d'aorte patient-spécifique - également appelés fantômes - sains et pathologiques et à un large panel de conditions d’écoulement. Des fantômes dotés de caractéristiques optiques et mécaniques spécifiques ont été fabriqués par injection de silicone et impression 3D pour se rapprocher du comportement de l'aorte humaine. Différents fluides imitant le sang ont été conçus pour étudier l'impact de la représentation non- newtonienne plus complexe du sang par rapport à la simplification newtonienne. En effet, le comportement rhéofluidifiant du sang est souvent négligé dans la littérature en affirmant que la représentation newtonienne est équivalente. Cette étude montre que les écoulements newtoniens dans un fantôme d'aorte sain ont tendance à sous-estimer la contrainte de cisaillement et le déplacement des vortex. Cela peut conduire à une mauvaise interprétation des zones à risque et des mécanismes pathologiques. La représentation non-newtonienne est donc plus adaptée à l’étude de l'hémodynamique aortique. Enfin, le banc expérimental a été développé en lien étroit avec des simulations numériques centrées sur la chirurgie assistée pour la dissection aortique. Des visualisations d’écoulements non-newtoniens ont été réalisés avec le simulateur in vitro}et la PIV sur des fantômes de dissection aortique patient-spécifique et comparées aux résultats numériques sur les mêmes modèles. Cela a permis la confrontation et l'inter-validation des deux approches. Le simulateur aortique développé est un outil puissant pour mieux analyser et comprendre l'hémodynamique aortique afin de compléter des investigations in vivo et in silico

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caminar la manzana... la calle era una red una cárcel la casa, peligro, blasfemias en las heridas viejas, ya no existes, no eres, peligrosa la casa, el auto con la fiera y un desgano el árbol del desnudo te da verguênza, lloras, duele el llanto y el ahora solo y gris hoy no tiene un mañana ni escalera de sol