Search results for "Dolo"
showing 10 items of 4274 documents
Fungi and Sediments
2000
Fungi are saprophytic organisms that can form lichens in symbiosis with an alga. Along with lichens, they excrete large quantities of organic acids, contributing to rock dissolution and neoformation of crystals, mainly oxalates and carbonates. Fungi contribute to the accumulation of manganese and iron as desert varnish and play a major role in the calcium cycle inside calcretes and carbonate soils in arid zones. Fungi constitute an important part of calcified filaments found in calcretes. They are covered with calcium oxalate crystals, which can transform into calcite during early diagenesis. They can also precipitate needle-fiber calcite, a common form of CaCO3 found in soils and calcretes…
Coarse-grained cryogenic aragonite as end-member of mineral formation in dolomite caves
2018
Abstract Cryogenic carbonate particles (single crystals and aggregates) have recently been recognized as important witnesses of permafrost dynamics, as they can be used to estimate the thickness and timing of development of permafrost. In this study, the petrography and geochemistry of coarse-grained cryogenic aragonite (CGCAr) identified in Zoolithen Cave in NE Bavaria, Germany, are described in detail for the first time. We provide a sequence of carbonate precipitation during freezing, where CGCAr mark the final crystallization phase in freezing water on ice. Our results support the notion that host rock composition, solution chemistry, and cave ventilation play an important role for arag…
Geochemistry and mineralogy of travertine deposits of the SW flank of Mt. Etna (Italy): Relationships with past volcanic and degassing activity
2007
Abstract Travertine deposits outcropping in the lower SW flank of Mt. Etna were studied for their mapping, as well as for their chemical, mineralogical and isotopic compositions. These deposits are dated to about 24 to 5 ka in the Adrano area, located at the western limit of the study area. In this area travertines show high Mg contents and are composed mostly of dolomite, thus apparently ruling out any primary deposition in favour of a diagenetic origin. Travertines outcropping near Paterno, in the east part of the study area, should be younger than 18 ka. Those located to the SSW of Paterno (Paterno–Diga) show high Sr contents and aragonite as dominant mineralogical phase, thus suggesting…
The origin and timing of multiphase cementation in carbonates: Impact of regional scale geodynamic events on the Middle Jurassic Limestones diagenesi…
2009
The Middle Jurassic carbonates of the eastern part of the Paris Basin display surprisingly low values of porosity and permeability (Φ < 15‰ and K < 0.5 mD). The main objective of this study is to determine the causes and timing of the cementation that altered the petrophysical properties of these carbonates thereby destroying their potential as oil reservoirs; a fate that did not befall their equivalents in deeper, central parts of the Paris Basin. Using petrographic and geochemical analyses (stable O and C isotopes, Sr isotopes, major elements), we identify six calcitic spar stages, two dolomite stages, and several episodes of fracturing and stylolitization ordered in paragenetic sequence.…
Fluid geochemistry in a low-enthalpy geothermal field along a sector of southern Apennines chain (Italy)
2020
Abstract The chemical and isotopic features of the fluids (water and gases) in the Lucane thermal area (southern Italy) have been investigated in order to verify their origin, water temperature in the geothermal reservoir, and to recognize the main natural processes concerning the water composition during ascent towards the surface. The Lucane geothermal system is placed in the southern sector of the Apennines chains, a seismically active area, close to the southern base of the Mt. Alpi carbonate massif. Along the study area, two main sets of high-angle faults form an almost orthogonal fault system that, as suggested by local structural geology, acts as a preferential pathway for uprising d…
Origin of clay minerals in soils on pyroclastic deposits in the island of Lipari (Italy)
2005
The island of Lipari (Italy) is characterized by calc-alkaline to potassic volcanism and a Mediterranean-type climate. The mineralogical and chemical features of two different soil profiles with ages of 92,000 and 10,000–40,000 y, respectively, have been investigated. There were no Andisols, but Vitric and Vertic Cambisols have developed at both sites. Although the morphology of the soils was similar, remarkable differences in the clay mineralogy between the two sites were observed. The site with the Vitric Cambisol was associated with the weathering sequence: glass → halloysite → kaolinite or interstratified kaolinite-2:1 clay minerals. Both sites had smectite in the clay fraction and, to …
Analyse économique des essais cliniques internationaux en cancérologie
2018
International audience; In oncology, as in other fields of medicine, international multicentre clinical trials came into being so as to include a sufficient number of subjects to investigate a clinical situation. The existence of tight budgetary constraints and the desire to make the best use of the resources available have resulted in the development of economic evaluations associated with these trials, which, thanks to their level of evidence and their size, provide particularly relevant material. Nonetheless, economic evaluations alongside international clinical trials raise specific questions of methodology with regard to both the design and the analysis of the results. Indeed, the cost…
'La canción' - 2018. Para estudiantes de Magisterio.
2018
Resum (en castellà) de la importància de la cançó com a eix vehicular a l'hora de posar en pràctica metodologies diverses davant l'assignatura 'Didàctica de la Música' de la Facultat de Magisteri. Methodological summary of the importance of The Song in the school. The Song as part of the course ' Didactica de la Música ' for teaching students.
Fuzzy subgroup mining for gene associations
2004
When studying the therapeutic efficacy of potential new drugs, it would be much more efficient to use predictors in order to assess their toxicity before going into clinical trials. One promising line of research has focused on the discovery of sets of candidate gene profiles to be used as toxicity indicators in future drug development. In particular genomic microarrays may be used to analyze the causality relationship between the administration of the drugs and the so-called gene expression, a parameter typically used by biologists to measure its influence at gene level. This kind of experiments involves a high throughput analysis of noisy and particularly unreliable data, which makes the …
Disabilità e dolore: il caso della cannabis terapeutica. Fisionomia e limiti del diritto alla cura nel decreto del Ministero della Salute 9 novembre …
2022
Il contributo illustra l’originale struttura del mercato della cannabis terapeutica, ricostruendo la legislazione italiana in materia, di cui si mette in luce la dubbia compatibilità con i principi di libera circolazione e di concorrenza. La specialità del settore è comunemente giustificata alla luce delle esigenze di salute pubblica, dell’ordine pubblico e della pubblica sicurezza la cui tutela è sottesa anche ai più recenti interventi normativi: specialità che non consente tuttavia di giudicare la regolazione della cannabis terapeutica conforme all’interpretazione consolidata degli articoli 49, 52, 56, 106 T.f.Ue e alla altrettanto stabile giurisprudenza della Corte costituzionale italia…