6,346 research outputs found
Archaeometric Study of the White Marbles from “Madonna Della Febbre” Altar in San Domenico Church (Cosenza, Southern Italy)
San Domenico Church was built between 1441 and 1468 and represents one of the most important historical buildings of the Cosenza area (Calabria, Southern Italy) thanks to its architectonic style and the works inside, such as the “Madonna della Febbre”, a notable marble altar dated back to the XVI century. The church, as well as the sculptural group, underwent various interventions over time, unfortunately scarcely documented; thus, in this paper, the characterization of six white marble samples coming from the altar, was carried out to determine their provenance. The samples were analyzed by means of complementary methodologies well known in the archaeometric field: polarized optical microscopy (POM); an electron probe micro analyzer coupled with an energy dispersive spectrometer (EPMA-EDS); inductively coupled plasma–mass spectrometry (ICP-MS); and isotope ratio mass spectrometry (IRMS). The results provided important information about the “Madonna della Febbre” altar, suggesting the presence of different typologies of marbles and hypothesizing their possible provenance, including Carrara and Docimium. It was not clear if these marbles were re-used materials but, regardless, the reported information adds precious elements to the history of the entire architectonic complex, providing new issues to be deepened
Le champ filonien à Zn-(Pb, Cu, As, Hg) du district minier de Fedj Hassène (Nord Ouest de la Tunisie): Minéralogie, Eléments en traces, Isotopes du Soufre et Inclusions Fluides
Le district minier de Fedj Hassène est situé à proximité de la frontière algéro-tunisienne, à 10 Km au sud de la ville de Ghardimaou. Il regroupe plusieurs filons à Pb-Zn, localement accompagnés par des sulfures de Cu, d'As et d'Hg. Les réserves sont estimées à 370.000 t à 10% de Zn et 0,2% de Pb. Les minéralisations remplissent des fractures subparallèles à la faille d'Ain Kohla de direction ESEWNW et des fentes d'extension qui recoupent les calcaires marneux du Turonien moyen. Le filon principal est formé par de la sphalérite massive brune et accessoirement par de la galène et de la barytine. Le minerai peut se présenter sous forme massive ou sous la forme de ciment de brèche. L'association minérale est composée par de la sphalérite, galène, chalcopyrite, pyrite et orpiment. La gangue est formée par de la calcite massive et localement par de la barytine et du quartz. L'analyse des éléments en trace dans la sphalérite révèle des teneurs en poids de 0,84% Fe, 0,14% Cd et 0,02% Mn. L'étude des inclusions fluides dans la calcite et la sphalérite montre l'existence d'un fluide caractérisé par une salinité de l'ordre de 23% poids équiv. NaCl à température décroissante lors de la mise en place des minéralisations (194 °C lors du dépôt de la calcite et 133 °C lors du dépôt de la sphalérite). Ce fluide est caractérisé par une densité comprise entre 1,00 g/cm3 et 1,11 g/cm3 avec une pression de piégeage estimée de 200 bars. La précipitation des sulfures parait être contrôlée par une chute de la température. Les mesures des isotopes du soufre dans la sphalérite donnent des valeurs de δ34S toutes positives et variant dans une gamme très restreinte comprise entre + 4,6‰ et 6,4‰ VCDT (moyenne=5,6‰). Ces valeurs indiquent une origine commune du soufre réduit qui est formé par les processus de ré duction thermique de sulfates. La source des sulfates admet les évaporites triasiques de la région comme reservoir potentiel. Les études géologiques et minéralogiques couplées à la microthermométrie des inclusions fluides et la géochimie des éléments en traces et des isotopes du soufre permettent de classer le gisement filonien de Fedj Hassène dans le groupe des gisements polymétalliques (Pb-Zn-As, Hg) typiques de la zone des nappes de la Tunisie du Nord et de l'Algérie nord-orientale
Quarkonium Results in PbPb Collisions at CMS
We summarize the results from the study of charmonium and bottomonium via the
dimuon decay channel in PbPb collisions with the CMS experiment. We discuss the
observation of sequential suppression of the Upsilon states. We present
preliminary results of prompt J/psi and psi' production, as well as of
non-prompt J/psis coming from the weak decay of b-quarks. This latter
measurement is sensitive to b-quark energy loss. We discuss the results and
compare to model predictions.Comment: 8 pages, 4 figures. Proceedings of 29th Winter Workshop on Nuclear
Dynamic
Impacto das habilidades escolares dos pais e do género dos alunos
Este artigo analisa a relação entre as atribuições causais e o rendimento
académico, apreciando como tais atribuições se diferenciam de acordo com o
nível de escolaridade dos pais e o género dos alunos. Para a avaliação das
atribuições causais recorremos à escala "Avaliação das Atribuições Causais e
Multidimensionais" (Barca, 2000) e a uma amostra de 1.144 alunos de escolas
públicas e privadas do Ensino Médio do Estado de Rondónia (Amazônia,
Brasil). Os resultados sugerem que, na generalidade das atribuições causais,
os alunos não se diferenciam de forma estatisticamente significativa
considerando o seu rendimento académico. A larga maioria dos alunos
valoriza as próprias capacidades e o esforço (atribuições internas) para
explicarem os seus bons resultados escolares, associando os fracos
resultados escolares à falta de sorte ou aos professores (atribuições
externas). Mesmo assim, os alunos de mais fraco rendimento justificam, em
maior percentagem, o seu bom desempenho escolar recorrendo à sorte e à
facilidade dos exames, recorrendo também mais frequentemente à falta de
capacidade para explicarem os seus fracos resultados escolares. As
atribuições causais não se diferenciam segundo o género dos alunos, muito
embora a atribuição dos fracos resultados escolares à falta de capacidade é
mais frequente nos rapazes cujos pais possuem baixas habilitações
académicas. Por último, a atribuição dos bons resultados escolares ao
esforço, ou os baixos resultados à falta de esforço, é mais frequente junto dos
alunos cujos pais possuem níveis mais elevados de escolaridade.This paper analyses the relationship between causal attributions and
academic achievement, considering attributions by students’ parents, school
level, and gender. To evaluate causal attributions we use the scale "Avaliação
das Atribuições Causais e Multidimensionais" (Barca, 2000) and a sample of
1144 students from basic public and private schools of Randonia State
(Amazônia, Brazil). Results suggest that, students’ causal attributions are not
differentiated by school achievement. Most students use internal attributions
(capacities and effort) to explain their good schools marks, using external
attributions (luck or teachers) to explain bad school classifications. Even
tough, poorest achievement students justify, in large percentage, better marks
by luck and facility of examinations, as well as low capacity to explain low
school classifications. The causal attributions are not related to students´
gender, but male students from parents with low academic certifications tend
to justify low school marks by lack of capacity. Finally, to justify good and bad
marks by effort, or lack of effort, is more frequent in the students from parents
with high school levels.Dans cet article nous présentons la relation entre les attributions causales et
le rendement académique, en tenant compte du niveau scolaire des parents
et le sexe des étudiants. Pour évaluer les attributions causales nous avons
utilisé le questionnaire "Avaliação das Atribuições Causais e
Multidimensionais" (Barca, 2000) et un échantillon représentatif de 1144
élèves fréquentant des institutions publiques et privées de l´enseignement
basique de Rondónia (Amazônia, Brasil). Les résultats montrent que les
élèves ne se différencient pas statistiquement dans leurs attributions en
fonction de leur rendement scolaire. La plupart des élèves valorisent leurs
efforts et capacités (causes internes) pour expliquer les bons résultats
académiques, et associent le manque de chance ou les professeurs aux
résultats les plus faibles (causes externes). Malgré ça, les élèves avec un plus
faible rendement justifient, dans un pourcentage supérieur, quelques résultats
positifs dus à la chance ou à la facilité des examens, ainsi comme ils
mentionnent leur manque de capacité pour expliquer les mauvais résultats.
Les attributions causales ne se différencient pas selon le sexe des élèves,
bien que l´attribution de l´ insuccès scolaire au manque de capacité soit plus
fréquente chez les élèves de sexe masculin dont les parents ont un niveau
d’aptitude académique plus bas. Finalement, l’attribution des bons résultats à
l’effort ou des faibles résultats au manque d’effort, est plus fréquente auprès
des élèves dont les parents ont un niveau plus élevé de scolarité.Fundação para a Ciência e a Tecnologia (FCT
Dinamica familia-centro escolar y rendimiento academico en alumnado de educacion secundaria de Galicia y Norte de Portugal
El contexto de las relaciones e interacciones familiares en relación con los hijos y su
rendimiento escolar ha sido estudiado con frecuencia por diferentes autores a lo largo de
los últimos veinte años. Dadas las diferentes tipologías de familias existentes en la
actualidad, se producen diferencias importantes en las relaciones e implicaciones
familiares que tienen sus efectos, también diferencias en dicho rendimiento escolar. Se
sabe que a mayor nivel formación académica y profesional de los padres, así parece que
existe un efecto positivo en el rendimiento.
Como objetivo general se trata de obtener evidencia empírica de la capacidad predictiva
y sus efectos sobre el rendimiento de las variables relacionadas con la percepción que
los alumnos tienen de la valoración de los padres sobre el esfuerzo, capacidad y trabajo
escolar de los hijos, así como de la valoración y satisfacción que manifiestan ante su
estudio y del refuerzo que hacen de su rendimiento académico.
La muestra está integrada por un total de 997 alumnos de escuelas públicas del Norte
de Portugal (n=510) y del Galicia (n=487). Las edades oscilan entre los 11, 12, 13 y 14
años, por lo tanto están entre el final de la educación primaria e inicio de la secundaria
obligatoria. Su procedencia es de tipo urbano, si bien la mayoría procede de la periferia
de ciudades como Porto, Guimaraes, Espinho, Chaves, así como de A Coruña, Ourense
y Santiago de Compostela. Como instrumentos de análisis se ha utilizado la Escala
CDPFA (Evaluación de Datos Personales, Familiares y Académicos), en concreto la
Subescala de Relación e Implicación Familia-Escuela. Se pretendía conocer la
capacidad predictiva de las variables que se señalan en el objetivo general del trabajo.
En cuanto al análisis de datos, se utiliza el paquete estadístico SPSS, versión 17.0,
realizando un análisis de regresión lineal múltiple en el que las variables independientes
son las referidas a las implicaciones/relaciones y familiares que los alumnos de Galicia
y norte de Portugal perciben en sus interacciones con sus padres, y la variable
dependiente será el rendimiento académico.
Resultados. Se ha comprobado que tiene una mayor incidencia en el rendimiento escolar
el contexto familiar del alumnado del norte de Poirtugal y de Galicia, en mayor medida
cuando ese contexto implica unas interacciones relacionadas con las expectativas
positivas hacia los hijos y el compromiso familiar (relaciones familia-escuela). Otras
variables que poseen una buena capacidad predictiva, aunque negativa, se relacionan
con la desvalorización del trabajo y esfuerzo realizado por el alumnado en el trabajo
académico, así como en su búsqueda de recompensas y refuerzos externos.GIPDAE - Grupo de Investigación en Psicoloxia do desenvolvemento e da aprendizaxe escolarCERXunta de Galicia - Consellería de Educación e Ordenación Universitaria (Secretaria Xeral)Ministerio de Educación y CienciaBase de Datos - ISOCFundación Universidade da CoruñaAyuntamiento de La Coruña - Concello de A CoruñaUniversidade do Minh
The potential mechanism of black crust development on the historic buildings in Cairo and Venice
The development of black crusts on natural stones of historic buildings is mainly related to the surrounded polluted atmosphere. The blackening of surfaces is caused, in fact, by the accumulation of air pollutants produced by human activity, especially carbon particles originating from the incomplete combustion of fossil fuel. Investigations of the chemical composition of such layers in the monuments can be the basis for planning suitable strategies for the protection and conservation of the built cultural heritage. Cairo (Egypt) and Venice (Italy) are two cities with a large amount of cultural heritage buildings; moreover, they suffer high level of air pollution. Black crust with the hosted stones from different sites in Historic Cairo, as well as samples of different archaeological sites in Venice city, were collected and analyzed by using several techniques: polarizing optical microscopy (OM), scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDS), infrared spectroscopic techniques (FT-IR) and laser ablation inductively coupled mass spectrometry (LA-ICP-MS).
The characterization of such samples provided information on the chemical composition of black crusts, the state of conservation of the substrates and the crust-stone interactions. The chemical study highlighted a different pattern of elements within the two cities.
Regarding the black crusts of Cairo, results suggest that the air pollution in Cairo is mainly related to vehicular traffic. Indeed, in the city there is high vehicular traffic almost 24 h a day and the direct impact of vehicle emissions is particularly severe.
Samples from the Venice show different composition in terms of heavy metals with respect to Cairo that can be explained with the emission from several industries sited in the near industrial center of Porto Marghera and Island of Murano. Moreover, the fuels used for marine transportation, which is abundant into the area, have a slight different fingerprinting in terms of metals with respect to the vehicles
Effects of weed control practices on plant diversity in a homogenous olive-dominated landscape (South-east of Italy)
Olive groves represent an important economic, agro-ecological, and cultural resource in the Mediterranean Basin. Weed management plays a fundamental role in their sustainable management. The aim of this work was to characterize and assess the plant diversity associated with different weed control practices, in a homogeneous olive-dominated landscape in the South-East of Italy. Sixty-five vegetation plots were sampled in orchards treated with different weed control practices: mowing, tillage, and use of chemical herbicides. The multi-response permutation procedure was used to test the hypothesis of no difference among the treatments. The relationships between plots were visualized by means of non-metric multidimensional scaling ordination. A generalized linear mixed model was used to analyze the relationships between weed control practices and life forms, chorotypes, and diversity indexes. The results showed that the three weed control practices determined slightly different plant communities. Chemically weeded orchards showed an impoverished floristic composition and the lowest diversity, whereas mowing and tillage yielded similar values. These latter two treatments differed for the percentages of hemicryptophytes and therophytes. Moreover, different from other studies, we did not find plant species of particular concern for biodiversity conservation. We hypothesize that this result is due to the monotonous structure of the agro-landscape we investigated, where natural elements are almost lacking. From this point of view, a correct management of agro-districts should consider both the agronomic practices at the level of the individual olive groves and the structure of the agro-landscape
STAR Results on High Transverse Momentum, Heavy Flavor and Electromagnetic Probes
We summarize here recent results from the STAR collaboration focusing on
processes involving large momentum transfers. Measurements of angular
correlations of di-hadrons are explored in both the pseudorapidity (eta) and
azimuthal (phi) projections. In central Au+Au, an elongated structure is found
in the eta projection which persists up to the highest measured pT. After
quantifying the particle yield in this structure and subtracting it from the
near-side yield, we observe that the remainder exhibits a behavior strikingly
similar to that of the near-side yield in d+Au. For heavy flavor production,
using electron-hadron correlations in p+p collisions, we obtain an estimate of
the b-quark contribution to the non-photonic electrons in the pT region 3-6
GeV/c, and find it consistent with FONLL calculations. Together with the
observed suppression of non-photonic electrons in Au+Au, this strongly suggests
suppression of b-quark production in Au+Au collisions. We discuss results on
the mid-rapidity Upsilon cross-section in p+p collisions. Finally, we present a
proof-of-principle measurement of photon-hadron correlations in p+p collisions,
paving the way for the tomographic study of the matter produced in central
Au+Au via gamma-jet measurements.Comment: 8 pages, 4 figures. Proceedings of "Quark Matter 2006", 19th
International Conference on Ultra-Relativistic Nucleus-Nucleus Collision
Towards Complex Tissues Replication: Multilayer Scaffold Integrating Biomimetic Nanohydroxyapatite/Chitosan Composites
This study explores an approach to design and prepare a multilayer scaffold mimicking interstratified natural tissue. This multilayer construct, composed of chitosan matrices with graded nanohydroxyapatite concentrations, was achieved through an in situ biomineralization process applied to individual layers. Three distinct precursor concentrations were considered, resulting in 10, 20, and 30 wt% nanohydroxyapatite content in each layer. The resulting chitosan/nanohydroxyapatite (Cs/n-HAp) scaffolds, created via freeze-drying, exhibited nanohydroxyapatite nucleation, homogeneous distribution, improved mechanical properties, and good cytocompatibility. The cytocompatibility analysis revealed that the Cs/n-HAp layers presented cell proliferation similar to the control in pure Cs for the samples with 10% n-HAp, indicating good cytocompatibility at this concentration, while no induction of apoptotic death pathways was demonstrated up to a 20 wt% n-Hap concentration. Successful multilayer assembly of Cs and Cs/n-HAp layers highlighted that the proposed approach represents a promising strategy for mimicking multifaceted tissues, such as osteochondral ones
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