Search results for "MAF"
showing 10 items of 846 documents
Tectono-Magmatic Evolution, Age and Emplacement of the Agardagh Tes-Chem Ophiolite in Tuva, Central Asia: Crustal Growth by Island arc Accretion
2004
Publisher Summary The Agardagh Tes–Chem ophiolite in Tuva, Central Asia, is part of the Central Asian Mobile Belt which formed during subduction–accretion processes lasting from the early Neoproterozoic to the late Palaeozoic. The Agardagh Tes–Chem ophiolite marks the northwestern border of the Tuva–Mongolian Massif (TMM), which comprises several intrusive and metamorphic complexes. These complexes consist of metatonalites, gneisses, migmatites, amphibolites, marbles, quartzites, low-grade metasedimentary rocks and minor ultramafic lenses, and radiometric ages range between 536 and 464 Ma. Field observations suggest that the southwestern part of the Tes–Chem unit represents the lower to int…
Geochemistry, geochronology and isotope geology of Nakfa intrusive rocks, northern Eritrea: products of a tectonically thickened Neoproterozoic arc c…
2001
Abstract The north-south-trending Neoproterozoic volcano-sedimentary plutonic associations in northern Eritrea are part of the Nubian Shield. The Nakfa intrusive rocks range in composition from gabbro to syeno-diorite to granite and alkaline syenite and intrude supracrustal rocks of volcanic and sedimentary origin. All granitoid rocks are metaluminous or slightly peraluminous and have typical I-type chemical signatures. The calc-alkaline intrusive rocks and the alkaline syenites have geochemical characteristics (e.g. low Nb values) typical of arc intrusives and plot as volcanic arc granites on various discriminant diagrams. Single zircon evaporation Pb-Pb ages and conventional multigrain U-…
Chapter 16 Pre-eruptive vapour and its role in controlling eruption style and longevity at Soufrière Hills Volcano
2014
We use volatiles in melt inclusions and nominally anhydrous phenocrysts, with volcanic gas flux and composition, and textural analysis of mafic inclusions to estimate the mass of exsolved vapour prior to eruption at Soufriere Hills Volcano (SHV). Pre-eruptive andesite coexists with exsolved vapour comprising 1.6–2.4 wt% of the bulk magma. The water content of orthopyroxenes indicates a zone of magma storage at pressures of approximately 200–300 MPa, whereas melt inclusions have equilibrated at shallower pressures. Inclusions containing >3 wt% H2O are enriched in CO2, suggesting flushing with CO2-rich gases. Intruding mafic magma contains >8 wt% H2O at 200–300 MPa. Rapid quenching is accompa…
Punti di forza, criticità e prospettive del “doppio binario” nella legislazione antimafia
2022
Lo scritto mira ad analizzare le dinamiche evolutive della legislazione antimafia, focalizzandosi, soprattutto, sui limiti e sulle prospettive di sviluppo del c.d. doppio binario nell’accertamento e nella repressione dei reati di criminalità organizzata mafiosa.
Lo scettro alla prefettocrazia: l'indefinita pervasività del sottosistema antimafia delle grandi opere e il caso emblematico della 'filiera'
2013
Il contributo analizza in via critica le disposizioni contenute nel codice antimafia, volte ad apprestare misure di contrasto alla criminalità organizzata. SEbbene tale obiettivo sia pprezzabile, l?a. manifesta perplessità in ordine ad una generalizzazione delle misure di tutela preventiva, con particolare riferimento al caso dell "filiera"
Verso una prospettiva di cambiamento individuale e collettivo nei territori influenzati dal dominio mafioso.
2009
“Me lo offre un caffè?”: Una ricerca qualitativa sulla ‘collusione di strada’ a Palermo [“Would you offer me a coffee?”: A qualitative research on ‘s…
2016
Il presente lavoro si propone come studio pilota sulla collusione in terre di mafia. I suoi oggetti di interesse sono Palermo e i “suoi” posteggiatori “abusivi”, figure oggi aggrovigliate al panorama geo-politico della città di cui parlano le strade, gli accadimenti mediatici e la cronaca giudiziaria del capoluogo siciliano. Ci siamo in tal senso chiesti: chi sono questi soggetti sociali? E quali sono le motivazioni della loro presenza ipertrofica in una città come Palermo? Grazie ai dati raccolti attraverso 21 “interviste da strada”, possiamo affermare che il problema è complesso e, come afferma Leoluca Orlando, riguarda posteggiatori e posteggianti, in uno stretto intreccio di collusioni …
Fysikaalinen valaistus ja reaaliaikaiset heijastukset
2016
Epäsuora valaistus, kuten ympäristön heijastukset, ovat tärkeä osa uskottavaa tietokonegrafiikkaa. Tarvitaan kuitenkin fysikaalinen valaistusmalli, jotta epäsuoran valon vaikutus olisi realistinen. Vasta viime aikojen näytönohjainten tehokkuuden kasvu on mahdollistanut fysikaalisen epäsuoran valaistuksen mallintamisen reaaliajassa. Koska epäsuoran valaistuksen laskeminen on erittäin raskasta, joudutaan kuitenkin tekemään arviointia, jotta reaaliaikainen toteutus olisi mahdollista. Tässä tutkielmassa esitellään fysikaalisen valaistuksen perustaa ja annetaan esimerkkejä reaaliaikaisista heijastusmenetelmistä. Lopuksi evaluoidaan kahta heijastustekniikkaa, ympäristötutkaimia ja kuvapuskuriheij…
Statistical upscaling of ecosystem CO2 fluxes across the terrestrial tundra and boreal domain: Regional patterns and uncertainties
2021
The regional variability in tundra and boreal carbon dioxide (CO2) fluxes can be high, complicating efforts to quantify sink-source patterns across the entire region. Statistical models are increasingly used to predict (i.e., upscale) CO2 fluxes across large spatial domains, but the reliability of different modeling techniques, each with different specifications and assumptions, has not been assessed in detail. Here, we compile eddy covariance and chamber measurements of annual and growing season CO2 fluxes of gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem exchange (NEE) during 1990–2015 from 148 terrestrial high-latitude (i.e., tundra and boreal) sites to a…
The ABCflux database: Arctic-boreal CO2flux observations and ancillary information aggregated to monthly time steps across terrestrial ecosystems
2022
Past efforts to synthesize and quantify the magnitude and change in carbon dioxide (CO2) fluxes in terrestrial ecosystems across the rapidly warming Arctic–boreal zone (ABZ) have provided valuable information but were limited in their geographical and temporal coverage. Furthermore, these efforts have been based on data aggregated over varying time periods, often with only minimal site ancillary data, thus limiting their potential to be used in large-scale carbon budget assessments. To bridge these gaps, we developed a standardized monthly database of Arctic–boreal CO2 fluxes (ABCflux) that aggregates in situ measurements of terrestrial net ecosystem CO2 exchange and its derived partitioned…