1,924 research outputs found
Alberto Rex González y la vigencia de sus aportes a la arqueología de cazadores-recolectores de Argentina.
Se reseñan los trabajos pioneros realizados por Alberto Rex González acerca de la arqueología de los grupos cazadores-recolectores, entre las décadas de 1940 y 1950, y se discute la vigencia de algunas de sus ideas y propuestas. Estos inauguraron nuevas perspectivas e interrogantes, sentando las bases para una nueva etapa en el desarrollo de la arqueología argentina, poniendo el énfasis en la definición de secuencias cronológicas y en los contextos culturales. Como resultado de sus trabajos en sitios de las Sierras Centrales (pcias. de Córdoba y San Luis) como los de yampitín, el Abrigo de Ongamira y la Gruta de Intihuasi, logró establecer un esquema cronológico-cultural que sirvió de referencia para la mayor parte de los estudios sobre cazadores-recolectores que se realizaron en nuestro país, y que aún continúa en uso en gran medida.publishedVersio
The Pleistocene-Holocene transition (11.000 - 9.000 BP) in the Córdoba Sierras (Argentine Republic)
Recientes investigaciones en las Sierras de Córdoba (sector central de Argentina) consiguieron identificar contextos arqueológicos tempranos y confirmar la presencia humana durante la Transición Pleistoceno-Holoceno. A partir del análisis de las evidencias arqueológicas correspondientes a la Transición y de los postulados teóricos de la ecología del comportamiento humano, se propone un modelo que sostiene que las sociedades cazadoras-recolectoras que habitaron la región durante ca. 11.000 – 9.000 AP habrían implementado estrategias adaptativas basadas en la captura de animales de alta tasa de retorno, en un escenario de gran movilidad, amplios rangos de acción y muy bajas densidades poblacionales. Current investigations in the Mountain ranges of Córdoba (central sector of Argentina) were able to identify early archaeological contexts and to confirm the human presence during the Pleistocene-Holocene Transition. From the analysis of the archaeological evidences corresponding to the Transition and the theoretical postulates of the behavioral ecology, a model sets out that maintains that the hunting-gatherers societies that inhabited the region during ca. 11.000 – 9.000 BP would have implemented adaptive strategies focused on the high return rates prey hunting, in a scenery of the great mobility, ample ranks of action and very low population densities.
Prácticas cotidianas y Reproducción social. Un estudio de los ámbitos residenciales del primer milenio D.C. en el Valle de Tafí.
Esta investigación problematizará el análisis de las actividades realizadas dentro de unidades residenciales durante el primer milenio d.C. (entre 200 años a.C. y 800 años d.C.) en el sitio La Bolsa 1. Éste se ubica en el norte del Valle de Tafí, noroeste de la provincia de Tucumán (Argentina), y está conformado por 21 unidades residenciales y algunas estructuras de cultivo. Dicho estudio será encarado desde la Arqueología Doméstica, intentando construir una visión acerca de las actividades cotidianas de esta sociedad, de las prácticas sociales de los agentes y de sus relaciones sociales a partir del análisis de la Unidad 14publishedVersio
Projectiles and intensification processes: an approach from Boyo Paso 2 ca. 1500-750 BP (Sierras de Córdoba, Argentina)
Se presentan los resultados obtenidos del análisis tecno-tipológico efectuado sobre las puntas de proyectil recuperadas en el sitio Boyo Paso 2 (1500-750 AP, Sierras de Córdoba, Argentina), intentando establecer cómo la dinámica socioeconómica tardía se reflejó en el diseño de los artefactos. Los cabezales fueron analizados consignando atributos tipológico-descriptivos, clasificados en subgrupos tipológicos y finalmente adscritos funcionalmente. El subgrupo tipológico de puntas de proyectil con pedúnculo diferenciado, aletas entrantes y limbo triangular corto de tipo isósceles dominó el conjunto, siendo la calcedonia y el ópalo la roca seleccionada para su elaboración. También se documentaron puntas de proyectil de dimensiones ligeramente mayores en cuarzo, con limbo triangular y base escotada, así como fragmentos asignados a puntas de proyectil de hueso con pedúnculo aserrado y aletas entrantes. La diversidad de cabezales recuperados, junto con los distintos sistemas de enmangue, la adopción generalizada del arco como forma de propulsión, el empleo selectivo de rocas y la incorporación de materias primas óseas, es interpretada como un indicador arqueológico de que la caza no era una actividad complementaria. Por el contrario, integraría junto al cultivo y la recolección un sistema económico de tipo mixto, en donde la flexibilidad fue uno de los rasgos definitorios.This paper presents the techno-typological analysis carried out on the projectile points of Boyo Paso 2 (1500-750 year BP, Sierras of Córdoba, Argentina), in order to assess how the dynamic of the late prehispanic sociocultural process influenced the design of hunting weapons. Projectile points were described in techno-typological terms, classified in typological subgroups and functionally assigned to arrow or dart point. The subgroup of tiny arrowpoints with short triangular-shaped blade, contracted stems and barbed shoulders dominates the assemblage. All of them were made of opal and chalcedony, a high quality rock for tool knapping. Moreover, a subgroup of quartz unstemmed with a triangular-shaped blade and concave base dartpoints as well as another subgroup of bone arrowpoints with triangular-shaped blade, straight stems and barbed shoulders were also recognized. The diversity of projectile point-types and hafting methods identified in Boyo Paso 2, along with the extensive use of the bow, the selection of high-quality lithic raw material and the incorporation of bone-tipped projectiles, led to interpret that hunting was not a complementary subsistence activity. Instead, it was integrated in a mixed foraging and cultivation economy where flexibility was one of its defining traits.Facultad de Ciencias Naturales y Muse
Aproximación al balance energético nocturno invernal de la playa del río Quequén Grande
Se realiza una investigación del balance energético nocturno invernal en las playas y estuario del río Quequén Grande. Para ello se realizaron mediciones de temperatura en los sedimentos a distintas profundidades, en el agua y en el aire. Para el cálculo de los flujos turbulentos se utilizaron las fórmulas aerodinámicas de masa. Con las temperaturas observadas se calculó el coeficiente de difusividad térmica. Su valor resultó comparable con aquellos publicados en la literatura. Los gradientes verticales de temperatura del sedimento fueron importantes, a pesar de ser condiciones nocturnas e invernales. Estos son significativamente modificados por la inundación de la marea. Los flujos del calor del suelo y la evaporación resultaron las componentes más importantes del balance de energía en presencia de viento en la playa, mientras que con condiciones de calma el flujo radiativo adquirió mayor relevancia. El balance energético en el agua fue considerablemente menor.An investigation about the balance energy flux was carried out in the beaches of the Quequén Grande River Estuary. Measurements of temperature of air, water and sediment at different levels were obtained. The bulk aerodynamical formulas were used in the calculation of the turbulent fluxes. The thermal diffusivity was calculated from the observations. The value was comparable to others published in the literature. Vertical temperature gradients in the sediment were significant, even though the measurements were performed during the night and in winter time. The sediment thermal gradients were significantly modified by the tidal inundation. Soil and latent heat flux were the most important components of the balance equation for the beach under windy conditions. However, the radiative flux was important with calm weather conditions. The energy balance components in the water were smaller than in the beach ones.Asociación Argentina de Geofísicos y Geodesta
Soluciones Creativas de Intervención (LUGH)
En este texto se puede encontrar información sobre los antecedentes del proyecto LUGH ITESO Soluciones creativas de intervención, así como los objetivos del trabajo que incluyen la vinculación entre empresas socialmente responsables con escenarios, comunidades, organizaciones u otros esfuerzos de la sociedad por mejorar su entorno. De este modo la empresa obtiene un beneficio en términos de posicionamiento, a la vez que produce un beneficio social tangible. Durante el período primavera 2016, se desarrollaron estrategias y piezas de comunicación para las organizaciones Plenitud de vida, Concertando México, Juntos por los demás y Capeltic. En este informe se incluye también la descripción del método de trabajo que el proyecto propone para la realización de estrategias de comunicación e intervención social
Effect of Systemic Hypertension With Versus Without Left Ventricular Hypertrophy on the Progression of Atrial Fibrillation (from the Euro Heart Survey).
Hypertension is a risk factor for both progression of atrial fibrillation (AF) and development of AF-related complications, that is major adverse cardiac and cerebrovascular events (MACCE). It is unknown whether left ventricular hypertrophy (LVH) as a consequence of hypertension is also a risk factor for both these end points. We aimed to assess this in low-risk AF patients, also assessing gender-related differences. We included 799 patients from the Euro Heart Survey with nonvalvular AF and a baseline echocardiogram. Patients with and without hypertension were included. End points after 1 year were occurrence of AF progression, that is paroxysmal AF becoming persistent and/or permanent AF, and MACCE. Echocardiographic LVH was present in 33% of 379 hypertensive patients. AF progression after 1 year occurred in 10.2% of 373 patients with rhythm follow-up. In hypertensive patients with LVH, AF progression occurred more frequently as compared with hypertensive patients without LVH (23.3% vs 8.8%, p = 0.011). In hypertensive AF patients, LVH was the most important multivariably adjusted determinant of AF progression on multivariable logistic regression (odds ratio 4.84, 95% confidence interval 1.70 to 13.78, p = 0.003). This effect was only seen in male patients (27.5% vs 5.8%, p = 0.002), while in female hypertensive patients, no differences were found in AF progression rates regarding the presence or absence of LVH (15.2% vs 15.0%, p = 0.999). No differences were seen in MACCE for hypertensive patients with and without LVH. In conclusion, in men with hypertension, LVH is associated with AF progression. This association seems to be absent in hypertensive women
Plant chemicals and the sexual behavior of male tephritid fruit flies
Plant compounds affect insects in many different ways. In addition to being a food source, plants also contain secondary metabolites that may have positive and negative impacts on insects. The influence of these compounds on sexual behavior, in particular, has been the focus of many recent studies. Here, we review the existing literature on the effects of plant compounds on the sexual behavior of tephritid fruit fly males. We put special focus on polyphagous species whose males congregate in leks, where females exert strong mate selection. We first summarize the main findings related to plant compounds that increase male signaling behavior and attraction of females and consequently increase mating frequency, a phenomenon that has been recorded mainly for species of Anastrepha and Ceratitis. In other tephritid species, males are attracted to phenylpropanoids produced by plants (such as methyl eugenol or raspberry ketone) that, upon encounter, are consumed and sequestered by males. These compounds, or metabolic derivatives, which normally have negligible nutritional value, are included in the pheromone and also confer advantages in a sexual context: enhanced female attraction and improved male mating success. These phenomena have been reported for several Bactrocera species as well as for Zeugodacus cucurbitae. Because many tephritid species are serious pests, the effect of plant compounds on male behavior has been explored for potential incorporation into control strategies such as the sterile insect technique (SIT). We conclude noting several factors, such as age and nutrition during larval and adult stage, that modulate the effect of plant compounds on male mating behavior as well as some prominent gaps that preclude a thorough understanding of the plant-mediated enhancement of male sexual performance and hence limit our ability to effectively utilize phytochemicals in pest control strategies.Instituto de GenéticaFil: Segura, Diego Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Belliard, Silvina A. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Vera, María Teresa. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Bachmann, Guillermo Enrique. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ruiz, María Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Tucumán. Facultad de Agronomía y Zootecnia; ArgentinaFil: Jofre-Barud, Flavia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Juan; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Fernández, Patricia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Delta del Paraná; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Lopez, M. Liza. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Juan; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Shelly, Todd E. United States Department of Agriculture. Animal and Plant Health Inspection Service; Estados Unido
Progression From Paroxysmal to Persistent Atrial Fibrillation. Clinical Correlates and Prognosis
Objectives: We investigated clinical correlates of atrial fibrillation (AF) progression and evaluated the prognosis of patients demonstrating AF progression in a large population. Background: Progression of paroxysmal AF to more sustained forms is frequently seen. However, not all patients will progress to persistent AF. Methods: We included 1,219 patients with paroxysmal AF who participated in the Euro Heart Survey on AF and had a known rhythm status at follow-up. Patients who experienced AF progression after 1 year of follow-up were identified. Results: Progression of AF occurred in 178 (15%) patients. Multivariate analysis showed that heart failure, age, previous transient ischemic attack or stroke, chronic obstructive pulmonary disease, and hypertension were the only independent predictors of AF progression. Using the regression coefficient as a benchmark, we calculated the HATCH score. Nearly 50% of the patients with a HATCH score >5 progressed to persistent AF compared with only 6% of the patients with a HATCH score of 0. During follow-up, patients with AF progression were more often admitted to the hospital and had more major adverse cardiovascular events. Conclusions: A substantial number of patients progress to sustained AF within 1 year. The clinical outcome of these patients regarding hospital admissions and major adverse cardiovascular events was worse compared with patients demonstrating no AF progression. Factors known to cause atrial structural remodeling (age and underlying heart disease) were independent predictors of AF progression. The HATCH score may help to identify patients who are likely to progress to sustained forms of AF in the near future. \ua9 2010 American College of Cardiology Foundation
b-tagging in DELPHI at LEP
Abstract: The standard method used for tagging b-hadrons in the DELPHI experiment at the CERN LEP Collider is discussed in detail. The main ingredient of b-tagging is the impact parameters of tracks, which relies mostly on the vertex detector. Additional information, such as the mass of particles associated to a secondary vertex, significantly improves the selection efficiency and the background suppression. The paper describes various discriminating variables used for the tagging and the procedure of their combination. In addition, applications of b-tagging to some physics analyses, which depend crucially on the performance and reliability of b-tagging, are described briefly
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