152 research outputs found
Characterization of the W ores at the Santa Comba mine, NW Spain
No full textThe NW of the Iberian Peninsula is characterized for hosting W-Sn deposits related to peraluminous variscan granites. One of them is the Santa Comba mine, located 45 km to the northwest of Santiago de Compostela, Spain. The mine is set in a poly-intrusive epizonal complex which fits the Endogranite-Stockscheider-Exogranite model (Nesen, 1979). This deposit features two types of mineralization containing cassiterite (SnO2), wolframite (FeMnWO3), and scheelite (CaWO4): a low tonnage high-grade mineralization concentrated in the quartz vein system that crosscuts the whole complex, and high tonnage low-grade disseminated mineralization hosted in the youngest intrusion (endogranite). The disseminated mineralization is related to zones of pervasive high-temperature hydrothermal alteration and stockwork-like systems, sometimes sharing features with porphyry-like deposits. A unique feature of this deposit is that the disseminated ore is enriched in wolframite but from a certain depth becomes enriched in scheelite. In this study, we applied microprobe analysis (EPMA), Raman spectroscopy, and a textural study through the petrographic microscope to identify and examine the characteristics of each ore.Depto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEpu
La iglesia de San Torcuato de Santa Comba de Bande (Orense): arqueología de la arquitectura
No full text46 páginas, 16 figuras.[ES] Con este trabajo se pretende una finalidad principal, dar a conocer los resultados del estudio de arqueología de la arquitectura del edificio de Santa Comba de Bande. También se discuten algunos elementos cronológicos de la iglesia, relacionándolos con los datos conseguidos y con el estado del conocimiento de nuestra arquitectura altomedieval.[EN] With this article a main objective is intended, to present the results of the archaeology of architecture study of Santa Comba de Bande building. Also some chronological elements of the church are discussed related to data obtained and the state of our knowledge on Early Medieval architecture.Peer reviewe
INTERNATIONAL AGENCY FOR RESEARCH ON CANCER MONOGRAPHS (IARC)
No full textAuthor reply pp. 86-7. In taliano
Santa Comba de Bande (Orense). Arquitectura y documentación escrita
Get PDFThe application of the stratigraphic method to the study of architecture implies, in more than a few cases, arguing against the traditional ideas in place in each case. Santa Comba de Bande is one example of this. The uncritical reading of a document from the nearby monastery of Celanova was first used to sketch an idea of the origin and evolution of the temple that has profoundly marked the various approaches to the building during more than a century of research. The results from the analysis of facings show a series of contradictions between the contents of the document and material reality, which makes it necessary to relativize the value of the document in question as a source of reliable information, while also showing the dangers involved in working from aprioristic principles in archaeological interpretation.La aplicación del método estratigráfico al estudio de la arquitectura está suponiendo, en no pocos casos, entrar en conflicto con las ideas tradicionales vigentes en cada caso. Santa Comba de Bande es un ejemplo de ello. La lectura acrítica de un documento procedente del cercano monasterio de Celanova sirvió en su momento para trazar un guión sobre el origen y evolución del templo que ha marcado profundamente los diferentes acercamientos al edifico a lo largo de más de un siglo de investigación. Los resultados del análisis de paramentos evidencian una serie de contradicciones entre la noticia textual y la realidad material que obligan a relativizar el valor del documento en cuestión como fuente de información fidedigna así como evidenciar los peligros que entraña, en la interpretación arqueológica, partir de ideas apriorísticas
Characterization of the disseminated W-Sn mineralization in the Santa Comba deposit
No full textDocumento de acceso restringido. Para más información diríjase al/los director/es del Trabajo de Fin de Máster.
The access to this document is restricted. Please contact the director/s of the work in case you wish to read it.El wolframio, también llamado tungsteno, es uno de los metales considerados a día de hoy críticos para la Unión Europea. Esto es debido a que su producción está prácticamente monopolizada por China y la falta de su suministro afectaría a la producción industrial de componentes electrónicos y herramientas de corte. Esta situación nos lleva a reconsiderar la importancia del abastecimiento de los recursos minerales en la sociedad actual y la explotación de yacimientos nacionales con gran potencial, como es el caso de la mina de Santa Comba.
Los yacimientos de W-Sn son comunes en el Oeste de la península, se encuentran asociados a granitoides de tipo S de edad Varisca, que se generan por la fusión de meta-sedimentos alumínicos (Villaros et al., 2009) y pueden estar enriquecidos en Sn o W. Este es el caso de Panasqueira, el mayor depósito de W de Europa y una de las mayores minas de wolframio del mundo, así como las minas de la Parrilla, San Finx o Barruecopardo. En concreto, el yacimiento de Santa Comba es dominante en W y se localiza dentro de una cúpula granítica enriquecida en wolframita ((Fe, Mn) WO3) pero que a partir de cierta profundidad se torna rica en scheelita (CaWO4). La relación entre ambas menas de W ha sido tema de discusión, pero nunca se ha indagado en detalle sobre su naturaleza. Este tipo demineralización diseminada incrementa significativamente el potencial económico de la mina y es en ello donde se focaliza este trabajo. En concreto el estudio se centra en la relación entre los dos tipos de mineralización diseminadas, una de scheelita y otra de wolframita.
Se cree que en esta mina se produce un fenómeno conocido como “scheelitización”, un proceso mediante el cual la scheelita reemplaza a la wolframita. A pesar de ser un fenómeno frecuente hasta la fecha se sabe muy poco sobre las condiciones en las que tiene lugar. Sobre una serie de muestras seleccionadas sobre testigos de sondeos, se ha determinado la mineralogía y tipo de alteraciones presentes, además de la presencia, tipo y composición de los minerales de wolframio. Con los resultados obtenidos mediante diversas técnicas(microscopía óptica microsonda electrónica, espectroscopia Raman DRX y SEM) se han planteado tres hipótesis sobre la relación wolframita/scheelita para explicar la secuencia paragenética de estos minerales en el endogranito de Santa Comba.
Adicionalmente se ha estudiado la posibilidad de emplear las variaciones composicionales de la wolframita como indicador genético. Concretamente se ha utilizado el ratio hubnerita(MnWO3) / ferberita (FeWO3) y a pesar de que se puede obtener cierta información sobre la mineralización, no se reconoce como un buen indicador del origen de los fluidos.Depto. de Geodinámica, Estratigrafía y PaleontologíaDepto. de Mineralogía y PetrologíaFac. de Ciencias GeológicasTRUEsubmitte
Madrid viejo : cronicas, avisos, costumbres, leyendas y descripciones de la Villa y Corte en los siglos pasados
No full textAnte
Analisi citazionale e indicatori bibliometrici nel modello Open Access
Get PDFThis article is focused on the bibliometric methods used for research evaluation, within the well known field of the bibliometrics which uses mathematical and statistical techniques to analyze the publications distribution patterns, and to explore their impact into the scholarly communities. While the bibliometric methods are used more often in the LIS, bibliometrics offers a wide range of applications in a variety of fields of knowledge. Since the research evaluation requires a double approach: quantitative (bibliometric analysis) and qualitative (peer-review, panel...), the fundamental idea is that the measurement of the scientific knowledge uses both the methods.
Though the IF or impact factor is the most well known bibliometric index, is not the only one suggested by ISI (now Thompson) to refer. In the Open Access world are spreading a wide number of initiatives and projects regarding the “bibliometrics” field, in which are being testing alternative solutions to the traditional IF, for example the Eigenfactor, the Hirsch index and its variations like the g-index, a-index, h-b-index, tools that mark a meaningful change in this fascinating field.
While the indicators “author-produced” are the citations, those “reader-produced” are usage data collected through webserver and linkresolver logs. A quantitative bibliometric indicator of new generation is the Usage Factor UF, complementary but non substitutive of traditional or alternative impact factor indicator. It will be necessary to organize the log data collection to share methods to obtain significant analysis. The article goes over some examples of new tools/projects for citational analysis in the Web area, among these the Web Impact Factor (WIF), and for the statistical analysis of logs and data, both bringing back to the new science known as metric of the web or Webometric.
Within the OAI framework there are many research projects of the webometric type, involving the intellectual output archivied into the repositories and their impact within the constitutive processes of the scholarly communication.
The theory assuming that an open access article in more likely to be read and therefore cited is matter of international debates and object of several studies, aimed to analyze the effects of the open access model and of the download on the citational impact. The article closes with a critical report on some of the most important works investigating the validity of this theory, from the original study of Lawrence, on Nature 2001, to the most recent works, the three postulates of Kurtz, the analysis run in 2006 by the Cornell’s Library staff on the MathSciNet database, the study of Moed which imposed a completely new methodological level with the introduction of the “variable citation window”.
Useful tools for the citational bibliometric analysis, on the statistical usage measurement of the researchs for the successful data monitoring, should be in the hands of the research producers, not in the hands of those commercial oligopoles that can influence the investment strategies and the national and international policies for the research
A arte rupestre da Serra de Passos/Santa Comba - Garraia (portugal) no contexto da Península Ibérica. Um projeto de investigação para doutoramento
Get PDFApresenta-se neste texto o projecto de investigação para doutoramento intitulado «A arte
rupestre da Serra de Passos/Santa Comba -Garraia no contexto da Península Ibérica. Modos de partilha
de grafismos no âmbito da integração social e ideológica das comunidades da Pré-história Recente» que
tem sido desenvolvido pela signatária, desde Setembro de 2020, no âmbito do doutoramento em
Estudos do Património, variante Arqueologia, na Faculdade de Letras da Universidade do Porto.
Na Serra de Passos/Santa Comba - Garraia (concelhos de Mirandela, Valpaços e Murça, norte de
Portugal) destaca-se o maior conjunto de Arte esquemática pintada em Portugal, cujo valor único
transcende o território português, sendo também o maior conjunto do Noroeste peninsular e da zona sul
da fachada atlântica europeia. O seu estudo global nunca foi, porém, realizado. Num contexto de
investigação regional, já profícuo em dados arqueológicos, a não integração do potencial de informação
que a Serra fornecerá é uma lacuna incontornável no entendimento da Pré-história regional e peninsular,
lacuna essa que visamos colmatar. Realizaremos a prospecção da Serra e o estudo científico dos seus
grafismos.Num discurso atualizado, assumindo os grafismos como elementos ativos da cultura material,
discutiremos os modos de ocupação e de interação social, ideológica e identitária das comunidades que
ocuparam a região do VI ao II milénioAC,facultando assim um incontestável contributo ao entendimento
das relações intercomunitárias peninsulares na Pré-história recente.This text aims to present the PHD project «The rock art of Passos/Santa Comba-Garraia Mountain, in the context of the Iberian Peninsula. Ways of sharing graphisms in Late prehistoric communities’ social and ideological sphere». This PHD project has been developed by the author, since September 22, in the 3rd Cycle of Studies in Heritage Studies - Archaeology, in the Faculty of Arts and Humanities of University of Porto. In Passos/Santa Comba-Garraia Mountain (located in the counties of Mirandela, Valpaços and Murça, north of Portugal) we highlight presence of the major group of painted schematic rock art in Portugal, which value exceeds the Portuguese territory as it is also the major set of the northwest Iberia or of the south of the European Atlantic façade. However its study, as a whole, as never been done. In the context of a vast regional research, the absence of a con-substantiated interpretation of Passos/Santa Comba-Garraia data representes a gap in the knowledge of regional and Iberian Late prehistory. That’s the gap we aim to fill within this project. According to updated methodologies we are doing the Mountain survey and the scientific record and study of the rock art. In our approach we assume graphisms as material cultural active elements and, according to that perspective we will discuss the prehistoric occupation, social and ideological interaction and identity among communities that occupied the region from the 6th to the 2nd millennium BC
Scholarly communication and open access : research communities and their publishing patterns [New Trends in Scholarly Communication : how do Authors of different research communities consider OA?]
Get PDFAt the time of the Budapest Declaration, self-archiving supporters looked like a revolutionary, "anti-commercial publishers" movement. Today, after some years debate (and technological innovation in research and scientific e-publishing), antagonist positions are able to compromise and consider the tradeoffs.
What is really changing in the Authors' attitude towards institutional or disciplinary repositories, and peer reviewed open access journals?
Many recent papers have investigated these topics. From these sources we can note that Biomedical Authors behave differently from Physicists, Astronomers and Mathematicians, who have been using open archives for such a long time. Therefore we intend to analyze these different trends in the diverse communities.
Several aspects also deserve a careful attention: the role of new OA journals in evaluation processes (i.e. their impact and citations), implementation and maintenance costs of institutional repositories, the evolution of bibliometric indicators.
We intend also to discuss the role of libraries in service innovation and e-publishing promotion. The main areas where a key role may be played are: institutional repository management and users' training, the promotion of OA journals and information about evaluation methods (both qualitative and quantitative).
We think that the transition towards new communication models may be a great opportunity that libraries have to be ready to support
Mucin and carbon nanotube-based biosensor for detection of glucose in human plasma
Get PDFThis work reports an amperometric enzyme-electrode prepared with glucose oxidase, which have been immobilized by a cross-linking step with glutaraldehyde in a mixture containing albumin and a novel carbon nanotubes-mucin composite (CNT-muc). The obtained hydrogel matrix was trapped between two polycarbonate membranes and then fixed at the surface of a Pt working electrode. The developed biosensor was optimized by evaluating different compositions and the analytical properties of an enzymatic matrix with CNT-muc. Then, the performance of the resulting enzymatic matrix was evaluated for direct glucose quantification in human blood plasma. The novel CNT-muc composite provided a sensitivity of 0.44 ± 0.01 mA M −1 and a response time of 28 ± 2 s. These values were respectively 20% higher and 40% shorter than those obtained with a sandwich-type biosensor prepared without CNT. Additionally, CNT-muc based biosensor exhibited more than 3 orders of magnitude of linear dynamic calibration range and a detection limit of 3 μM. The short-term and long-term stabilities of the biosensors were also examined and excellent results were obtained through successive experiments performed within the first 60 days from their preparation. Finally, the storage stability was remarkable during the first 300 days.Fil: Comba, Fausto Nahuel. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Romero, Marcelo Ricardo. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentina. Universidad Nacional de Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación y Desarrollo en Ingeniería de Procesos y Química Aplicada; ArgentinaFil: Garay, Fernando Sebastian. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Baruzzi, Ana Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Fisicoquímica; Argentin
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