Sindicador de canales de noticias
Espacialidad y materialidad de un conjunto de unidades domésticas tempranas -CA. 300-600 D.C.- de Anillaco (La Rioja, Argentina); Spatiality and materiality of a set of early household -c. 300-600 AD- of Anillaco (La Rioja, Argentina)
Sabatini Vargas, Gabriela Inés; Garate, Enrique Rubén
En este trabajo nos proponemos abordar la espacialidad y materialidad de las comunidadesaldeanas entre ca. 300 a 600 d.C. en el piedemonte oriental de la Sierra de Velasco en el área de lalocalidad de Anillaco (Castro Barros, La Rioja). Para ello seleccionamos un conjunto residencial deescala doméstica que nos permitió acercarnos a los primeros procesos formativos de Anillaco y a susprácticas cotidianas. Presentamos los resultados obtenidos del relevamiento y excavación del sitioUchuquita. Analizamos la espacialidad residencial, los rasgos arquitectónicos y la distribución delos conjuntos cerámicos y faunísticos mediante herramientas estadísticas de interpolación Kriging.Así, reconocimos parámetros distribucionales y áreas de concentración del registro cerámico y óseovisualizando la disposición de los objetos, la organización del espacio y las prácticas cotidianasdesarrolladas en los recintos. Distinguimos el Número Mínimo de Vasijas (NMV) según serie finay ordinaria y realizamos análisis arqueofaunísticos identificando patrones de uso y consumo.Observamos que algunos rasgos culturales se prolongaron espacial y temporalmente en otrascuencas de la Sierra de Velasco, dando cuenta de una continuidad en las formas de hacer.; In this paper, we propose a spatial and material approach to the study of the village community that lived between c. 300 and 600 AD in the eastern piedemont of Anillaco’s town (Castro Barros, La Rioja). For this we selected a residential complex of household scale that allows us to determine the first formative processes of Anillaco and the daily practices. We presented the results obtained of surveys and excavations in Uchuquita site. We analyzed from a comprehensive and contextual point of view the residential spatiality, the architectural features and the distribution of the ceramic and faunistic sets, using statistical interpolation tools: Kriging. Thus, we recognized distributional parameters and areas of concentration of the ceramic and bone records, visualizing the arrangement of such objects in the housing areas, the organization of the space and the daily practices developed in them. We distinguished the Number Minimum of Vessels (NMV) according to the fine and ordinary series and we perform archaeofaunistics analysis identifying patterns of use and consumption. We observed that some cultural traits extend spatially and temporally in other basins of the Sierra de Velasco, accounting for continuity in the ways of doing things.
Mecanismos de emplazamiento y destrucción de los domos lávicos asociados a la caldera del cerro Blanco, puna austral
Mecanismos de emplazamiento y destrucción de los domos lávicos asociados a la caldera del cerro Blanco, puna austral; Mechanisms of emplacement and destruction of lava domes related to the Cerro Blanco Caldera, southern Puna
Baez, Walter Ariel; Chiodi, Agostina Laura; Bustos, Emilce; Arnosio, José Marcelo; Viramonte, Jose German; Giordano, Guido; Alfaro Ortega, Blanca Beatriz
En la Puna Austral se desarrolló durante el Cuaternario un importante sistema de calderas de colapso con depósitos piroclásticos y lavas de composiciones ácidas asociados: El Complejo Volcánico Cerro Blanco. Como parte de su actividad más reciente se destaca la erupción que dio lugar a la caldera del cerro Blanco, a la cual se asocia una serie de domos lávicos cuya buena exposición permite abordar el estudio de los mecanismos de emplazamiento y destrucción de domos de composiciones ácidas. Este trabajo presenta una descripción de la distribución espacial, morfología y características litofaciales de los domos del Complejo Volcánico Cerro Blanco, incluyendo los depósitos piroclásticos asociados a los mismos. Los datos obtenidos permiten inferir que el emplazamiento de los domos se produjo de manera endógena y exógena en función de las variaciones en las tasas de ascenso y efusión del magma, así como en relación con el volumen y duración del emplazamiento de cada cuerpo dómico. La destrucción de los domos fue explosiva (erupciones vulcanianas) y no explosiva (colapsos gravitacionales). Ambas situaciones se vieron favorecidas por tasas de ascenso y efusión globales relativamente bajas. La destrucción gravitacional de los domos se relacionó fundamentalmente a la ocurrencia de morfologías inestables con un importante desarrollo vertical. Las erupciones vulcanianas ocurrieron como resultado de dos mecanismos principales: la sobrepresurización del magma dentro del conducto y la interacción con agua externa. Además ocurrieron explosiones freáticas menores responsables de destruir parcialmente algunos de los cuerpos dómicos.; An important quaternary collapse caldera system associated with acid pyroclastic deposits and lavas was developed in the Southern Puna: Cerro Blanco Volcanic Complex. The most important recent activity was the caldera forming Cerro Blanco eruption which has a series of lava domes related. The good exposure of these domes provides the opportunity to study the mechanisms of growth and destruction of silicic lava domes. This paper presents a description of the spatial distribution, morphology and lithofacial characteristics of the lava domes related to the Cerro Blanco Volcanic Complex, including the associated pyroclastic deposits. The data obtained suggest that the growth of the domes was both endogenous and exogenous in response to variations in ascent and effusion rate, as well as in function of volume and span of growth of each dome. The destruction of the lava domes was explosive (vulcanian eruptions) and non-explosive (gravitational collapses). Both situations were favored by slow ascent and effusion rate. The gravitational destruction of the domes occurs as a result of the instability of domes with large vertical development. The vulcanian eruptions occur as a result of two main processes: magma pressurization into the conduit and external water input. Also minor phreatic explosions destroyed partially some of the domes.
New provenience analysis of Late Holocene archaeological obsidians from southern Patagonia (Santa Cruz province, Argentina)
New provenience analysis of Late Holocene archaeological obsidians from southern Patagonia (Santa Cruz province, Argentina)
Nami, Hugo Gabriel; Giesso, Martín; Castro, Alicia Susana; Glascock, Michael
X-ray fluorescence (XRF) and neutron activation analysis (NAA) methods were employed on a sample of obsidians from Santa Cruz province (southern Argentina). Results obtained from 81 specimens from two sources and a number of archaeological sites located in NE and SE Santa Cruz shows that the obsidians contain trace elements indicating diverse origins.
Juegos de lenguaje sociales y palabras que dañan. Un estudio sobre la interpretación aplicada de la obra del segundo Wittgenstein
Juegos de lenguaje sociales y palabras que dañan. Un estudio sobre la interpretación aplicada de la obra del segundo Wittgenstein
Gamero Cabrera, Isabel Gloria
En este artículo voy a profundizar en una interpretación aplicada de la obra del segundo Wittgenstein, propuesta por José Medina, Miranda Fricker y Peg O’Connor, entre otros. Estos autores equiparan juegos de lenguaje y formas de vida, entienden las reglas de los juegos como normas sociales y trasladan la argumentación del filósofo vienés a un ámbito sociopolítico. Concretamente, José Medina propone un argumento en oposición a los juegos de lenguaje sociales, que es la versión social al argumento de Wittgenstein en oposición a los juegos de lenguaje privados. En segundo lugar, analizaré dos casos: las distintas denominaciones de los indios huicholes y el uso del plural inclusivo por parte de algunos feminismos. Lo más interesante de estos dos casos es que estos grupos proponen significados privados o usos del lenguaje que sólo parecen ser válidos para ellos. Preguntaré si estos usos se pueden entender como juegos de lenguaje sociales y ser criticados desde los argumentos de Medina. Este estudio de casos servirá para evaluar la adecuación, validez y límites de esta interpretación de la obra de Wittgenstein.; The main aim of this paper is to study in depth an applied interpretation of the later Wittgenstein’s work, developed by José Medina, Miranda Fricker and Peg O’Connor, among other authors. They equate the concepts of “language-games” and “forms of life”, understand the rules of the games as social norms and place Wittgenstein’s arguments in the socio-political field. Specifically, José Medina coins an argument against social language-games, which is the social version of Wittgenstein’s argument against private language-games. Secondly, I will analyse two cases: the different denominations of the Huichol Indians and the uses of the inclusive plural proposed by some feminists. The main interest of these cases is that both groups propose private meanings or particular uses of some terms, which seems to be valid just for them. I will ask whether these uses can be understood as social language-games and thus be criticised by Medina’s arguments. This case analysis is addressed to evaluate the accuracy, validity and the limits of this interpretation of Wittgenstein’s work.
Paisas y gringos. Neorruralidad serrana, transformaciones relacionales e identidades emergentes, Argentina
Paisas y gringos. Neorruralidad serrana, transformaciones relacionales e identidades emergentes, Argentina; Paisans and gringos. Highland neo-rurality, relational transformations, and emerging identities in Córdoba, Srgentina
Trimano, Luciana Geraldine
En las últimas décadas, los pueblos “rurales” del valle de Traslasierra, en la provincia de Córdoba, Argentina, experimentaron un proceso de transformación debido al impacto de la movilidad urbana. Desde la mirada etnográfica de un estudio de caso en la localidad serrana de Las Calles, analizamos una tendencia poblacional que involucra a sectores inmigrantes de clase media y alta. Los sujetos son etiquetados por la sociedad receptora con el nombre de “gringos”, por detentar capital económico, cultural y simbólico, pero sobre todo por ser una segunda oleada migratoria que siguió a la primera, protagonizada por inmigrantes ingleses a partir de la década de 1940. De modo transdisciplinar, reflexionamos acerca de un modelo de sociabilidad al que denominamos círculo iluminado para comprender rasgos de la “neorruralidad” argentina; For the last twenty years, “rural” towns in the Valle de Traslasierra, in the province of Córdoba, Argentina, have undergone fast social transformations attributed to the impact of urban migrations. Through an ethnographic case study in the hill town of Las Calles, we analyse the features of a population trend involving middle and upper class sectors from the big cities. These “neo-rural” subjects are tagged by the receiving society as “gringos” both because they flaunt financial, cultural, and symbolic capital, and also because they are a second migratory wave after the one started in the 1940s which involved English immigrants. Based on a transdisciplinary approach, we will reflect on the establishment of a sociability model we have named illuminated circle. Said conceptualization helps understand certain traits in the Argentinean “neo-rurality” phenomenon
Sellars on perceptual knowledge
Sellars on perceptual knowledge
Kalpokas, Daniel Enrique
In Empiricism and the Philosophy of Mind, after criticizing one of the forms that the Myth of the Given adopts, Sellars presents his own conception of epistemic justification. This conception, along with his criticism of the framework of the Given, has had a great impact on the analytic philosophy of the second half of twentieth century, an impact that still persists today. In this article, I aim to examine Sellars’s theory of epistemic justification in order to highlight two important problems with it. The first concerns the justification of observation reports; the second concerns the understanding of those reports. I argue that those problems do not find a suitable solution within Sellars’s theory of observational knowledge. My diagnosis is that the root cause of those problems lies in an inadequate conception of perceptual experience. This prevents Sellars from realizing the essential epistemic role that experience plays in the justification and understanding of such particular statements.
Influence of extrusion process conditions on starch film morphology
Influence of extrusion process conditions on starch film morphology
González Seligra, Paula Fabiana; Guz, Lucas Martín; Ochoa Yepes, Oswaldo Juan; Goyanes, Silvia Nair; Fama, Lucia Mercedes
The conditions of extrusion process for food packaging are determinant on their morphology and, as consequence, on their functionality. The effect of the screw speed of a starch-glycerol system extruded at the same temperature profile was evaluated. The process at 80 rpm led to a material with the starch completely gelatinized, while the systems fabricated at 40 rpm and 120 rpm presented broken starch grains. The morphology and density of the broken grains depended on the screw speed. The material at 120 rpm showed broken grains with smaller size and lower concentration than that observed in the system at 40 rpm. After pressing at 120 rpm, the film formed (TPS120) resulted similar than that at 80 rpm (TPS80), while the film at 40 rpm (TPS40) kept some broken grains. TGA of the material obtained at 40 rpm showed more than one degradation process of the glycerol due to the inhomogeneous glycerol dispersion. DRX revealed more cristallinity in TPS40, being TPS120 the most amorphous. TPS80 had the highest strain at break while the others the higher modulus and stress at break. Water vapor permeability of TPS80 and TPS120 showed similar results and lower than TPS40.
Optical function of the finite-thickness corrugated pellicle of euglenoids
Optical function of the finite-thickness corrugated pellicle of euglenoids
Inchaussandague, Marina Elizabeth; Skigin, Diana Carina; Dolinko, Andrés Ezequiel
We explore the electromagnetic response of the pellicle of selected species of euglenoids. These microorganisms are bounded by a typical surface pellicle formed by S-shaped overlapping bands that resemble a corrugated film. We investigate the role played by this structure in the protection of the cell against UV radiation. By considering the pellicle as a periodically corrugated film of finite thickness, we applied the C-method to compute the reflectance spectra. The far-field results revealed reflectance peaks with a Q-factor larger than 103 in the UV region for all the illumination conditions investigated. The resonant behavior responsible for this enhancement has also been illustrated by near-field computations performed by a photonic simulation method. These results confirm that the corrugated pellicle of euglenoids shields the cell from harmful UV radiation and open up new possibilities for the design of highly UV-reflective surfaces.
De oasis a desierto: Re-emergencias huarpes y la promesa del agua en las Lagunas de Guanacache
De oasis a desierto: Re-emergencias huarpes y la promesa del agua en las Lagunas de Guanacache
Calderon Archina, Maria Aldana
El presente trabajo retoma discusiones y reflexiones que fueron planteadas en mi Trabajo Final de la Licenciatura en Antropología. Puntualmente aquí me interesa retomar lo desarrollado en relación a la problemática del agua que afecta desde hace décadas al área de las (desecadas) Lagunas de Guanacache, centro oeste argentino, donde habita población rural y comunidades indígenas huarpes. Más específicamente, focalizaré en las Lagunas como punto de identificación de las historias de vida huarpe y cómo la falta de agua devino en tema de agenda e intervención estatal. Asimismo, ambas cuestione se encuentran articuladas y facilitaron el proceso de comunalización (Brow, 1990) de un grupo de familias autoadcriptas como huarpes del paraje La Represita, una pequeña localidad sanluiseña ubicada en el límite provincial con San Juan. De esta manera, parte de la apuesta de este artículo está en reconstruir a través de la problemática del agua el proceso de re-emergencia de un grupo de familias autoadscriptas como huarpes.
Habitats of ancient hunter-gatherers in the Puna: Resilience and discontinuities during the Holocene
Habitats of ancient hunter-gatherers in the Puna: Resilience and discontinuities during the Holocene
Yacobaccio, Hugo Daniel; Morales, Marcelo Raul; Hoguin, Rodolphe
Hunting groups are closely linked to the environments in which they live, especially in the deserts. This paper explores the relationship between people and desert environments in the long term using key concepts such as resilience, refugia and habitat loss. A thorough paleoenvironmental analysis was conducted to improve our understanding about continuities and discontinuities in the archaeological record of the South Andean highlands. This allowed us to test ideas about the availability of adequate human habitats during the Holocene. Cultural archives such as archaeofauna and lithic technology are employed to illustrate and discuss methodological perspectives for the identification and description of resilient human habitats in arid landscapes in the South Andean Puna.
Improving diabetes care at primary care level with a multistrategic approach: results of the DIAPREM programme
Improving diabetes care at primary care level with a multistrategic approach: results of the DIAPREM programme
Prestes, Mariana; Gayarre, Maria A.; Elgart, Jorge Federico; Gonzalez, Lorena; Rucci, Enzo; Paganini, Jose M.; Gagliardino, Juan Jose
To present results, 1 year postimplementation at primary care level, of an integrated diabetes care programme including systemic changes, education, registry (clinical, metabolic, and therapeutic indicators), and disease management (DIAPREM).
Lyapunov exponents and poles in a non Hermitian dynamics
Lyapunov exponents and poles in a non Hermitian dynamics
Gomez, Ignacio Sebastián
By means of expressing volumes in phase space in terms of traces of quantum operators, a relationship between the poles of the scattering matrix and the Lyapunov exponents in a non Hermitian quantum dynamics, is presented. We illustrate the formalism by characterizing the behavior of the Gamow model whose dissipative decay time, measured by its decoherence time, is found to be inversely proportional to the Lyapunov exponents of the unstable periodic orbits. The results are in agreement with those obtained by means of the semiclassical periodic–orbit approach in quantum resonances theory but using a simpler mathematics.
Anisotropic BV–L2 regularization of linear inverse ill-posed problems
Anisotropic BV–L2 regularization of linear inverse ill-posed problems
Mazzieri, Gisela Luciana; Temperini, Karina Guadalupe; Spies, Ruben Daniel
During the last two decades several generalizations of the traditional Tikhonov-Phillips regularization method for solving inverse ill-posed problems have been proposed. Many of these variants consist essentially of modifications on the penalizing term, which force certain features in the obtained regularized solution ([11,18]). If it is known that the regularity of the exact solution is inhomogeneous it is often desirable the use of mixed, spatially adaptive methods ([7,12]). These methods are also highly suitable when the preservation of edges is an important issue, since they allow for the inclusion of anisotropic penalizers for border detection ([20]). In this work we propose the use of a penalizer resulting from the convex spatially-adaptive combination of a classic L2penalizer and an anisotropic bounded variation seminorm. Results on existence and uniqueness of minimizers of the corresponding Tikhonov-Phillips functional are presented. Results on the stability of those minimizers with respect to perturbations in the data, in the regularization parameter and in the operator are also established. Applications to image restoration problems are shown.
Mancha angular del poroto: avances en su investigacion en la EEAOC
Mancha angular del poroto: avances en su investigacion en la EEAOC; Angular leaf spot of common bean: advances on its research at the EEAOC
Mamani Gonzales, Silvana Yacqueline; Vizgarra, Oscar N.; Espeche, Clara M.; Mendez, Diego Eduardo; Ploper, Leonardo Daniel
La mancha angular del poroto causada por el hongo Pseudocercospora griseola afecta el rendimiento y la calidad de la semilla. En Argentina esta enfermedad fue convirtiéndose gradualmente en una limitante del cultivo, por lo que sumanejo es un aspecto importante a tener en cuenta en la producción de poroto. En el presente trabajo se describen brevemente los resultados de las actividades llevadas a cabo por el proyecto Legumbres Secas de la Estación ExperimentalAgroindustrial Obispo Colombres (EEAOC) en la búsqueda de resistencia genética a esta enfermedad. Los trabajos comenzaron con la introducción de germoplasma desde el Centro Internacional de Agricultura Tropical a partir del cual seliberó TUC 550, la primera variedad resistente a mancha angular en Argentina. En la siguiente etapa se realizaron cruzamientos locales, utilizando como parentales resistentes los materiales seleccionados en las primeras valuaciones. Se obtuvieron así líneas avanzadas de poroto negro con niveles de resistencia superiores a los conseguidos en la etapa previa. También se identificaron nuevos parentales para futuras combinaciones, teniendo en cuenta que el trabajo de mejoramiento genético debe ser continuo debido a la alta variabilidad patogénica que presenta P. griseola.Palabras clave: evaluación de germoplasma, resistencia a Pseudocercospora griseola; Angular leaf spot of common bean, caused by the fungus Pseudocercospora griseola, affects yield and quality of bean seed. In Argentina this disease became gradually a limiting factor for the crop, so its management is an important aspect to consider in common bean production. In this work, the activities carried out by the Legumbres Secas project of the Estación Experimental Agroindustrial Obispo Colombres (EEAOC) in the search for genetic resistance to this disease are presented briefly. This work began with the introduction of germplasm from the International Center for Tropical Agriculture from which the variety TUC 550 was released, the first variety with resistance to angular leaf spot in Argentina. In the next stage, the project has carried out local crosses using as resistant parents those genotypes selected in the first evaluations. Advanced black bean lines were obtained with higher levels of resistance than those obtained in the previous stages. Also, new potential parents were identified for future combinations, considering that breeding for angular leaf spot resistance should be continuous because of the high pathogenic variability exhibited by P. griseola.
Fungal diversity at fragmented landscapes: synthesis and future perspectives
Fungal diversity at fragmented landscapes: synthesis and future perspectives
Grilli, Gabriel; Longo, Maria Silvana; Huais, Pablo Yair; Pereyra, Mariana; Verga, Ernesto Gustavo; Urcelay, Roberto Carlos; Galetto, Leonardo
Fungi are organisms with important roles in ecosystem functioning and services, but knowledge about how habitat fragmentation affect fungal diversity is biased by experimental approaches and it is spread in different trophic groups. We analyzed the empirical evidences of fungal diversity in fragmented landscapes, and proposed future perspectives for the study of these organisms under land use changes. Fungal diversity might be negatively affected by habitat fragmentation; however, this trend may differ in magnitude depending on fungal groups and their nutritional habits. In addition, due to the fact that fungal diversity at fragmented landscapes has been studied mainly through few indicators (e.g. isolation, area and edge effect); we propose incorporating the landscape structure and accurate spatio-temporal scales to the study of fungal diversity responses to fragmented landscapes. Together, this methodological refinement may allow improving knowledge on fungi when designing proper strategies for landscape management.
Mapping inundation probability due to increasing sea level rise along El Puerto de Santa María (SW Spain)
Mapping inundation probability due to increasing sea level rise along El Puerto de Santa María (SW Spain)
Fraile Jurado, Pablo; Álvarez Francoso, José I.; Guisado Pintado, Emilia; Sanchez Carnero, Noela Belen; Ojeda Zújar, José; Leatherman, Stephen P.
Global sea levels have risen through the twentieth and twenty-first centuries. This rise will almost certainly continue and probably accelerate during the rest of the twenty-first century, albeit there is strong disagreement about the range of future sea level rise due to uncertainties regarding scenarios and emission of greenhouse gasses. Although the impacts of sea level rise are diverse, inundation during high tides is one of the most obvious and immediate consequences. A probabilistic methodology for mapping the inundation hazard because of sea level rise has been applied to the coast of El Puerto de Santa María in the province of Cádiz in southwest Spain. This methodology involves a step forward since represents the full range of probabilities, associated with each scenario of sea level rise considered, and thus offers a more realistic view of the probability of inundation in each area. Results show large differences in the spatial distribution of probable inundation in urban areas and wetlands leading to different consequences for management actions.
Bioactive glasses as delivery systems for antimicrobial agents
Bioactive glasses as delivery systems for antimicrobial agents
Rivadeneira, Josefina; Gorustovich Alonso, Alejandro Adrian
Most biomaterial-associated infections are caused by opportunistic pathogens and bacteria that are regularly found within the microflora of the implant site. In addition, a biomaterial implant or device remains at risk of infection by hematogenous spread of bacteria disseminated from infections elsewhere in the body or from infected peri-implant tissue in revision surgery. The resulting infections are frequently accompanied by patient morbidity and discomfort and can lead to surgical replacement of the implant after lengthy, unsuccessful attempts to mitigate infections with antibiotic treatments. Therefore, extensive study is aiming to find new infection-resistant antimicrobial biomaterials and coatings for implants and devices to effectively reduce the incidence of biomaterial-associated infections. An overview of the in vitro and in vivo antimicrobial efficacies of the numerous biomaterials currently available is beyond the scope of this review. Herein, we provide a comprehensive review of bioactive glasses as biomaterial delivery systems for antimicrobial agents.
Primer reporte de un Área de Congregación de Zánganos de Apis mellifera (Hymenoptera: Apidae) de Argentina
Primer reporte de un Área de Congregación de Zánganos de Apis mellifera (Hymenoptera: Apidae) de Argentina
Galindo Cardona, Alberto; Quiroga, Oscar B.; Bianchi, Eliana Mariel; Ayup, María Marta
Natural reproduction of honeybees occurs in zones called drone congregation areas (DCA), visited by drones (males) and queens of several colonies. These places are open areas, protected from the wind by high vegetation cover and are very common near an apiary. Until now, there was none DCA reported in Argentina. First, we determine the fly activity of drones, watching the entrance and exit to the hives from 8:00 to 18:00 hours. We found two peaks, in 11:00 to 12:00 hours and 15:00 to 17:30. To find a DCA, we track the path of movement of drones using helium-filled balloons, kites and remotes flying. Each contact point of drones in the bait was georeferenced with a GPS to determine the path to a DCA. We found the first DCA in northern Argentina, close to queen?s cabin breeding in Alberdi, Tucumán (ARG). This study is important in biology for health monitoring and estimating the structure and genetic diversity of Apis mellifera L. in northern Argentina and for apiculture, to preserve regional ecotypes through a reproductive planning for beekeepers.; La reproducción natural de las abejas melíferas ocurre en zonas denominadas áreas de congregación de zánganos (ACZ), visitadas por machos, denominados zánganos, y reinas integrantes de varias colonias. Dichas áreas se caracterizan por ser abiertas,protegidas del viento por cubierta vegetal alta y es muy común encontrarlas cerca de un apiario. En la Argentina, hasta el momento no se había localizado ninguna ACZ. Primero se determinó el horario de actividad de zánganos, observando la entrada y salida a las colmenas de 8:00 a 18:00 horas. La actividad de los zánganos tuvo dos picos, de 11:00 a 12:00 horas y de 15:00 a 17:30 horas. Luego se hizo la identificación de la ruta de movimiento de zánganos, utilizando globos inflados con helio y barriletes. Cada punto de contacto de zánganos en el cebo, fue georeferenciado con GPS. Encontramos la primera ACZ en el norte de Argentina, cerca de una cabaña de crianza de reinas en Alberdi, Tucumán (ARG). Este estudio es importante ya que implementa una metodología para monitorear ACZ, la cual ayudaría en el estudio de la salud de las abejas y en la estimación de la estructura y diversidad genética de Apis melliferaL., también en apicultura, ya que brindaría una herramienta a los apicultores para la conservación de los ecotipos regionales mediante el planeamiento reproductivo de las abejas.
Connectedness of the algebraic set of vectors generating planar normal sections of homogeneous isoparametric hypersurfaces
Connectedness of the algebraic set of vectors generating planar normal sections of homogeneous isoparametric hypersurfaces
Sanchez, Cristian Urbano
Let M Sn+1 Rn+2 be a homogeneous isoparametric hypersurfaceand consider the algebraic set of unit tangent vectors generating planarnormal sections at a point E 2 M (denoted by bXE [M] TE (M)). Th epresent paper is devoted to prove that bXE [M] is connected by arcs.. This in turn proves that its projective image X [M] RP (TE (M)) also has this property.
Light and matter diffraction from the unified viewpoint of Feynman’s Sum of all Paths
Light and matter diffraction from the unified viewpoint of Feynman’s Sum of all Paths
Arlego, Marcelo José Fabián; Fanaro, Maria de Los Angeles
In this work, we present a pedagogical strategy to describe the diffraction phenomenon based on a didactic adaptation of the Feynman’s path integrals method, which uses only high school mathematics. The advantage of our approach is that it allows to describe the diffraction in a fully quantum context, where superposition and probabilistic aspects emerge naturally. Our method is based on a time-independent formulation, which allows modelling the phenomenon in geometric terms and trajectories in real space, which is an advantage from the didactic point of view. A distinctive aspect of our work is the description of the series of transformations and didactic transpositions of the fundamental equations that give rise to a common quantum framework for light and matter. This is something that is usually masked by the common use, and that to our knowledge has not been emphasized enough in a unified way. Finally, the role of the superposition of nonclassical paths and their didactic potential are briefly mentioned.
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