1,037 research outputs found
SEM-EDS characterization of historic mortar as a tool in archaeometric study: an updated analytical protocol tested on the Roman theatre of Aosta (NW Italy).
New petrographic and geochemical tracers for recognizing the provenance quarry of trachyte of the Euganean Hills, northeastern Italy
Gobernabilidad en Santa Cruz de la Sierra: Pautas para mayor transparencia y democracia local
A partir de los años ochenta se inició una nueva etapa democrática en Bolivia,
después de quince años de alternar entre gobiernos dictatoriales y constitucionales. La
profundización de la democracia fue prolongada (1978-1982), costosa, lenta y complicada.
El desarrollo de las democracias locales, como parte del proceso general, constituyó un
paso importante en esta consolidación y estuvo marcada por la aprobación de leyes que
promueven la descentralización y la participación popular, tendientes a fortalecer la
institucionalidad pública y a mejorar la calidad de vida de los ciudadanos, con una
distribución más equitativa de los recursos financieros administrados bajo el régimen de
vigilancia y control social. El proceso estuvo matizado por problemas de legitimidad y
gobernabilidad. Una vez superados los unos se presentaron otros, generando un debate
permanente y cambiante sobre el tema
SEM-EDS X-ray compositional maps for minero-chemical characterization of ancient pottery: a first application on Adrano pottery (NE Sicily, Italy).
Automated SEM‐EDS pottery classification based on minero‐chemical quantitative parameters: An application on ancient Greek pottery from Adrano (NE Sicily, Italy)
Late metamorphic veins with dominant PS-15 polygonal serpentine in the Monte Avic ultramafite
The ultramafic body of Monte Avic (Aosta Valley, Western Alps,
Italy) consists of antigorite serpentinite and Ti-clinohumite metadunite.
They host late metamorphic veins, up to a couple of centimeters thick,
compact, and homogeneous, with a “porcelain” appearance. Vein colors range
from yellowish to light greenish, light yellowish fading to white, or rare
orange. The veins consist of 15-sector PS-15 polygonal serpentine,
with chemical composition Mg2.85 Fe0.08 Si2.05 O7.05
[OH]3.95. Recognition of this unusual phase is supported by diagnostic
satellite reflections in the X-ray powder diffraction pattern (e.g., at
dobs of 2.502, 2.336, 2.151, and 1.966 Å) TEM images (showing
15-sector polygonal fibers, mostly 200 nm in diameter and a few µm in
length, forming a randomly oriented felt) and a µ-Raman wavenumber,
matching previous data. This different evidence affords the successful
distinction of PS-15 and PS-30, alternatively using TEM images, X-ray powder
diffraction, or the low- and high-wavenumber µ-Raman spectra. At Monte
Avic, the vein emplacement was accompanied by significant fluid pressure, as
suggested by deformation and dismembering of the host rock, with PS-15 grown
within isotropic stress microenvironments characterized by fluid-filled
voids. Random growth of the mass-fiber polygonal serpentine was favored by
low-strain conditions. PS-15 veins formed at the end of the long polyphase
Alpine orogenic evolution, with hydrous fluids possibly deriving from
serpentinite dehydration in the depth.</p
Yttrium Geothermometry Applied to Garnets from Different Metamorphic Grades Analysed by EPMA and µ-PIXE Techniques
Direct and indirect assessment of the amount of naturally occurring asbestos in fractured rocks
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