Search

Indium phosphide (InP) surfaces are greatly affected by ionic bombardment. We investigate the resulting surface perturbation through the use of the complementary analytical techniques of electrochemistry and X-ray photoelectron spectroscopy (XPS). Following bombardment, modifications to the surface were identified by a reduction in the dark open circuit potential in comparison to the pristine state. Through XPS studies, it was found that the sputtered surface was enriched with a metallic-like In contribution, which oxidized upon exposure to air. Cyclic voltammetry measurements confirmed this observation, with initial cathodic features related to an oxidized metallic In-enriched layer on the InP surface. Repeated cyclic voltammetry experiments resulted in the formation of a more In-rich overlayer due to a specific oxidation/reduction phenomenon. This behavior is very similar to that obtained by cathodic decomposition on InP surfaces.

En los últimos años, los medios masivos y dispositivos digitales han transformado las prácticas de comunicación científica a una escala global, con nuevas estrategias para transmitir conocimientos. Este trabajo reflexiona acerca de una experiencia de aplicación de tecnologías inmersivas para la comunicación pública de las investigaciones arqueológicas desarrolladas en un sitio con arte rupestre de la sierra de El Alto-Ancasti (Catamarca, Argentina). La cueva de La Candelaria, investigada desde la década de 1980, alberga un conjunto excepcional de pinturas rupestres. Sin embargo, muchos de estos saberes han permanecido en el ámbito académico, en formatos poco accesibles para muchas personas. Con el objetivo de sociabilizar este abrigo y los conocimientos académicos a públicos diversos, nos propusimos desarrollar una visita virtual, interactiva e inmersiva, de acceso libre y gratuito. Considerando los desafíos enfrentados durante su producción, en este trabajo reflexionamos sobre las oportunidades, ventajas y limitaciones que estas tecnologías presentan para la comunicación científica en Arqueología. Las conclusiones de este trabajo subrayan la importancia de incorporar etapas mantenimiento y retroalimentación del recurso generado para favorecer su impacto en la sociedad.

Introduction: Scientific evidence supports dermoscopy as an essential tool in dermatological diagnosis. Objectives: The objective is to know the factors that influence its use in Chilean dermatologists. Materials and Methods: Analytical cross-sectional study. An adapted version of the survey was submitted from the pan-European study by Forsea et.al. to members of the Chilean Society of Dermatology, between September and December 2020. Analysis using descriptive statistics and multivariate analysis with ordinal logistic regression looking for factors associated with greater use of. Results: 198 responses, mean age 46.3 years and 14.6 years on average practicing as dermatologists. 61.6% trained in dermoscopy during their residency. 98% use a dermatoscope. More than 80% consider dermoscopy useful for the diagnosis of melanomas, follow-up of melanocytic lesions, and diagnosis of pigmented and non-pigmented tumors. Between 50% and 70% consider it useful for monitoring non-melanocytic lesions, nail and hair pathologies. Greater confidence when evaluating pigmented and non-pigmented tumors and capillary pathology. Adjusting for age, sex, confidence, and education, participation in teaching was associated with greater use of dermoscopy in non-pigmented and pigmented tumors, and capillary pathology. Conclusions: Percentage of participation in the survey and training in dermoscopy higher than in the reference study, recognizing the usefulness of dermoscopy for the diagnosis and follow-up of tumor pathologies. Participating in teaching is a strong independent factor that is associated with a greater use of dermoscopy in Chile. Dermoscopy is positioned as a tool widely used by Chilean dermatologists in their daily practice.

This article aims to advance the understanding of the historical painting process at the archaeological site of Oyola (Sierra El Alto-Ancasti, Catamarca, Argentina). In particular, it intends to evaluate similarities and differences in the material composition of the pigmentary mixtures to glimpse the existence of ancient pictorial recipes. Microstratigraphic analyses of 28 black motifs were performed by scanning electron microscopy with elemental analysis by energy-dispersive X-ray spectroscopy (SEM-EDS) and micro-Raman spectroscopy (RS). The comparative study of these results pointed to the alternative use of two black pigments (charcoal and manganese oxides), combined, in some cases, with calcium sulfate. In this way it was possible to acknowledge certain aspects of the pictorial recipes that oriented the preparation of the black pigment mixtures, approaching some of the traditions and knowledge reclaimed. In order to understand these recipes in relation to the history of the site, the spatial dispersion, chronology, and some formal characteristics of the rock art motifs executed with them were evaluated. Since no clear trends were identified, a less normative definition of pictorial recipe is proposed, highlighting the shared aspects between painting episodes, without losing sight of the creative possibilities of each event. [ABSTRACT FROM AUTHOR]

In drinking water production from groundwaters, biological rapid sand filters (RSFs) can be used for ammonium and manganese removal in aerobic conditions. However, in some boreholes, a start-up duration of several months is required to reach the required removal capacity, leading to significant water losses. Moreover, in specific industrial cases, no exogenous biomass under the form of backwash water or activated sludge can be added to accelerate the process, and different approaches are seldom considered in the literature. With the aim of saving water, start-up strategies coupling water temperature increase and substrate dosing were studied to accelerate the installation of biological activities in a pilot plant fed with borehole water. These set-ups enabled a substantial acceleration of nitrification but no improvement of manganese oxidation in the experimental conditions, although the experiments showed no clear negative influence of nitrification, through nitrite accumulation, on biological manganese oxidation. To further save energy and reduce water loss, outlet water recirculation at a rate of 75% during the start-up phase was validated. The proposed start-up strategy enabled the complete installation of active biofilms with a mean start-up time reduction of 36% and water use reduction of 84% compared to the reference natural conditions. HIGHLIGHTS The accelerated start-up strategy designed for the production of drinking water yielded up to 90% of water saved in the best tested configuration.; Temperature increase and substrate dosing have a better impact on nitrification than on manganese oxidation.; No clear negative interaction between nitrification and manganese oxidation was observed.;

Las técnicas de aplicación de las pinturas rupestres resultan fundamentales para comprender sus procesos de producción, pues permiten acceder a las interacciones constitutivas entre seres, materiales, tiempos y espacios que se entablan al hacer los motivos. Sin embargo, son escasas las investigaciones centradas en identificar marcadores materiales específicos que permitan diferenciar entre la multiplicidad de técnicas de aplicación posibles. En líneas generales, estas se han inferido a partir de criterios poco explicitados. Este trabajo plantea un abordaje experimental de cuatro técnicas de aplicación (digital, con hisopo, con pincel y con palito) con vistas a detectar huellas específicas a cada una. Posteriormente, se aplican estos conocimientos para avanzar en el relevamiento macroscópico de las pinturas rupestres de la cueva de La Candelaria (departamento Ancasti, Catamarca). Ello posibilitó identificar huellas de diversas técnicas de aplicación en las pinturas del sitio, demostrando la importancia de retroalimentar los relevamientos in situ con estudios experimentales.

Abstract Could not be possible that rock paintings with similar hues and morphologies were the result of different paint preparations inside a cave but distanced in time? Is there any archaeometric approach that allow us to evidence these subtle differences? Aiming to address these inquires, in this work are presented the potentials of new physicochemical lines of evidence for characterization and differentiation of paint mixtures. This will improve the understanding of the technical heterogeneity and temporal complexity of painting sets executed in a particular archaeological site. In order to explore these points, the results obtained in the micro-stratigraphic studies of samples taken from the painted walls of Oyola, an archaeological site located in the northwest of Argentina, are presented. These samples have been analyzed by micro-Raman spectroscopy (mRS) and scanning electron microscopy with energy dispersive X-ray (SEM–EDS). The differences found by cross-section chemical studies could be explained as a consequence of two situations: 1-differences in the painting’s chemical components, either in the pigments involved or additives used; and, 2-differences in the physical properties of the mixtures such as stratum thickness and/or particle size. Also, in this article are explained each of the hypothesis, presenting the limits of these interpretations and pointing out future research challenges. As we discussed, it could be possible that the chemical and physical differences found between paint mixtures were the material expression of varied types of pictorial techniques.

El siguiente artículo expone los resultados de una investigación en la que uno de sus propósitos fue conocer las características de la llamada “empresa masculinizada”, representada por una minera de la ciudad de Copiapó de Chile y cómo, en función de aquello, dicha empresa produce y reproduce estereotipos, roles e identidades de género, desarrollando brechas, barreras e inequidades para el trabajo de las mujeres. El estudio mantuvo una perspectiva cualitativa y permitió, a través de entrevistas en profundidad, la develación de discursos sometidos a análisis de contenido. Las conclusiones plantean segregaciones horizontales y verticales de género; la construcción social de los cuerpos de las mujeres; y las restricciones intrínsecas y extrínsecas de género para las mujeres en el marco del trabajo en la minera, así como preguntas y desafíos que como sociedad nos tenemos que hacer para avanzar en una igualdad de género y justicia social.

Photovoltaic generation has stepped up within the last decade from outsider status to one of the important contributors of the ongoing energy transition, with about 1.7% of world electricity provided by solar cells. Progress in materials and production processes has played an important part in this development. Yet, there are many challenges before photovoltaics could provide clean, abundant, and cheap energy. Here, we review this research direction, with a focus on the results obtained within a Japan–French cooperation program, NextPV, working on promising solar cell technologies. The cooperation was focused on efficient photovoltaic devices, such as multijunction, ultrathin, intermediate band, and hot-carrier solar cells, and on printable solar cell materials such as colloidal quantum dots.