861 research outputs found
Microanalyses and Spectroscopic Techniques for the Identification of Pigments and Pictorial Materials in Monet's Pink Water Lilies Painting.
In this work, the technique and the pictorial materials employed by Claude Monet in Pink Water Lilies, presently housed at the National Gallery of Modern and Contemporary Art in Rome, were investigated. The painting underwent noninvasive investigations such as energy-dispersive X-ray fluorescence and visible reflectance spectroscopies. The combined use of these techniques allowed us to identify most of the inorganic pigments such as cobalt blue and violet, zinc oxide, cadmium yellow, vermilion, and mixtures. Particularly, the spectrophotometric curves allow for the detection of the anhydrous and hydrated chromium greens. Two micro-fragments of the painting were also examined with micro-Fourier transform infrared spectroscopy and the cross-sections obtained were analyzed with the optical microscope and with scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometry (EDS). Fourier Transform Infrared spectroscopy analyses allowed us to recognize the animal glue used for priming the canvas, which was covered with a ground layer consisting of calcite and lead white mixed with an oil binder. A lipidic binder was also detected in the color layer. Optical microscopy and SEM-EDS were useful to retrieve information about the stratigraphy, the distribution of pigments, and a more complete palette identification of phosphate, arsenate, and magnesium arsenate cobalt violets, and the red lake was possible
Planificación curricular y evaluación formativa no presencial en docentes de nivel primaria, Red Livitaca, Cusco, 2022
El presente trabajo tuvo como objetivo determinar la relación de la
planificación curricular con la evaluación formativa no presencial desde la
percepción de los docentes de nivel primaria de la Red Livitaca, en Cusco, donde
la propuesta metodológica, fue de tipo aplicado, de alcance correlacional, de
enfoque cuantitativo y de diseño no experimental, el cual consideró para formar
parte de la muestra a 100 docentes, a quienes, se les aplicó dos cuestionarios
con motivo de recoger información de las variables, las cuales con antelación se
llegaron a validar por tres especialistas y a determinar la confiabilidad de los
mismos, apoyados en el análisis del alfa de Cronbach. Respecto a los resultados,
se probó que los datos provienen de una distribución no normal, lo cual permitió
seleccionar la prueba de Spearman para el contraste estadístico, donde se
evidenció que la significancia fue de 0,000, facultando que se rechace la hipótesis
nula, además, la correlación fue de 0,538, siendo tal relación significativa, positiva
y de moderada intensidad, es decir, que una eficiente planificación curricular
guarda relación con una buena evaluación formativa no presencial o viceversa
Automated displacement measurements on historical canvases
Abstract Background In this paper we describe a configurable system based on laser displacement sensors for the contactless acquisition of 3D and 2D shapes of near-planar objects such as the paintings. Methods The system is based on two single-point laser triangulation sensors, a planar robot and a suite of software for driving the sensors, acquiring and post-processing the collected data. As a demonstration of the developed system we monitored three artifacts with the different aims to monitor the elastic properties of the artworks and the effectiveness of support frames in compensating the micro-climate fluctuations: the "Annunciazione" Antonello da Messina, the "Paliotto di San Domenico", and the "Portiera Oddi-Montesperelli". Results In the "Annunciazione" case, the canvas response to tensioning trials was analyzed. The collected data permitted to quantify a maximum displacement of 0.9 and 1.5 mm for the tensioning tests at 1 and 2 mm, respectively. In the "Portiera" case, the displacement difference between the left and right canvas sides was (1.0 ± 0.13)%, due to the inherent anisotropy of the material and by the structure of the artifact. In the "Paliotto" case, instead, minor displacement variations of the gilt leather due to the environment were observed, due to the analysis conducted prior of the restoration. Conclusions The overall obtained results demonstrated that the system is able to provide useful data for the art conservation field, with a max inaccuracy less than 100 μm
Confocal Imaging at 0.3 THz with depth resolution of a painted wood artwork for the identification of buried thin metal foils
A compact confocal terahertz microscope working at 0.30 THz based on all-solid-state components is used to locate buried thin metal foils in a painted wood artwork. Metal foils are used for decoration, and their precise localization under the pictorial layer is relevant information for conservation scientists and restorers, which can neither be obtained by X-ray radiography nor by spectroscopic imaging in the infrared, as we directly show here. The confocal microscopy principle based on the spatial pinhole concept is here implemented by positioning the first focus of an ellipsoidal reflector at the phase center of horn antennas coupled to Schottky diode detector and emitter mounted in rectangular waveguide blocks, together with an optical beamsplitter. The second focus of the reflector is mechanically scanned inside the sample in three dimensions. The predictions of diffraction theory for a confocal microscope at an imaging wavelength of 1.00 mm with numerical aperture of 0.53 are verified experimentally (1.2 and 2.8 mm for the lateral and the axial resolution, respectively). These values of resolution allow a precise determination of the position of buried metal foils in an ancient piece of art hence making restoration interventions possible
Dissecting Adaptation Mechanisms to Contrasting Solar Irradiance in the Mediterranean Shrub Cistus incanus
Molecular mechanisms that are the base of the strategies adopted by Mediterranean plants to cope with the challenges imposed by limited or excessive solar radiation during the summer season have received limited attention. In our study, conducted on C. incanus plants growing in the shade or in full sunlight, we performed measurements of relevant physiological traits, such as leaf water potential, gas exchange and PSII photochemistry, RNA-Seq with de-novo assembly, and the analysis of differentially expressed genes. We also identified and quantified photosynthetic pigments, abscisic acid, and flavonoids. Here, we show major mechanisms regulating light perception and signaling which, in turn, sustain the shade avoidance syndrome displayed by the ‘sun loving’ C. incanus. We offer clear evidence of the detrimental effects of excessive light on both the assembly and the stability of PSII, and the activation of a suite of both repair and effective antioxidant mechanisms in sun-adapted leaves. For instance, our study supports the view of major antioxidant functions of zeaxanthin in sunny plants concomitantly challenged by severe drought stress. Finally, our study confirms the multiple functions served by flavonoids, both flavonols and flavanols, in the adaptive mechanisms of plants to the environmental pressures associated to Mediterranean climate
Adding Organizations and Roles as Primitives to the JADE Framework
The organization metaphor is often used in the design and implementation
of multiagent systems. However, few agent programming languages
provide facilities to define them. Several frameworks are proposed to coordinate MAS with organizations, but they are not programmable with general purpose languages. In this paper we extend the JADE framework with primitives to program in Java organizations structured in roles and to enable agents to play roles in organizations. Roles facilitate the coordination of agents inside an organization and give new abilities in the context of organizations, called powers, to the agents which satisfy the requirements necessary to play the roles. As primitives to program organizations and roles we provide classes and protocols which enable an agent to enact a new role in an organization and to interact with the role by invoking the execution of powers, and to receive new goals to be fulfilled. Roles have state and behaviour, thus, they are instances of classes and are strictly connected with the organization offering them. Since roles and organizations can be on a different platform with respect to the role player, the communication with them happens via protocols. Moreover, since, besides using protocols, roles and organizations can have complex behaviours, they are implemented by extending the JADE agent class
Does a medical device nomenclature suitable for all purposes exist? Twenty years of Italian experience with the CND and its adoption in EUDAMED at European level
There are many purposes for using a nomenclature of medical devices. The Italian CND is a free public available nomenclature, arises from a comparison with existing nomenclatures and is structured to allow a connection with other systems. Since 2007 the CND is used, in the Italian database, for regulatory affairs in order to register and classify homogeneously medical devices from a technical and economics point of view; in 2019 the CND has been adopted from European Commission as official nomenclature. It is not possible to think that a nomenclature can meet all needs.
Owever, it is possible to guarantee the interoperability of different classification systems by adopting a single hierarchical nomenclature as a common basis from which to develop different "subclassifications" for different purposes. Aim of this paper is to present the Italian experience in the development of the national medical device nomenclature and its extension to the European level
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