Ethanol Sensing Properties of PMMA-Coated Fiber Bragg Grating

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Uniparental markers of contemporary Italian population reveals details on its pre-Roman heritage.

BACKGROUND: According to archaeological records and historical documentation, Italy has been a melting point for populations of different geographical and ethnic matrices. Although Italy has been a favorite subject for numerous population genetic studies, genetic patterns have never been analyzed comprehensively, including uniparental and autosomal markers throughout the country. METHODS/PRINCIPAL FINDINGS: A total of 583 individuals were sampled from across the Italian Peninsula, from ten distant (if homogeneous by language) ethnic communities--and from two linguistic isolates (Ladins, Grecani Salentini). All samples were first typed for the mitochondrial DNA (mtDNA) control region and selected coding region SNPs (mtSNPs). This data was pooled for analysis with 3,778 mtDNA control-region profiles collected from the literature. Secondly, a set of Y-chromosome SNPs and STRs were also analyzed in 479 individuals together with a panel of autosomal ancestry informative markers (AIMs) from 441 samples. The resulting genetic record reveals clines of genetic frequencies laid according to the latitude slant along continental Italy--probably generated by demographical events dating back to the Neolithic. The Ladins showed distinctive, if more recent structure. The Neolithic contribution was estimated for the Y-chromosome as 14.5% and for mtDNA as 10.5%. Y-chromosome data showed larger differentiation between North, Center and South than mtDNA. AIMs detected a minor sub-Saharan component; this is however higher than for other European non-Mediterranean populations. The same signal of sub-Saharan heritage was also evident in uniparental markers. CONCLUSIONS/SIGNIFICANCE: Italy shows patterns of molecular variation mirroring other European countries, although some heterogeneity exists based on different analysis and molecular markers. From North to South, Italy shows clinal patterns that were most likely modulated during Neolithic times

Sulfide chemistry of pyroxenites from the External Liguride Peridotite Massif, Italy - Implications for melt-rock interactions in the mantle.

The ophiolites of the Northern Apennine thrust and fold belt represent samples of deep subcontinental lithosphere from an oceancontinent transition in Mesozoic times. The External Liguride (EL) units consist of fertile lherzolites with MOR-type isotopic signatures and diffuse pyroxenite layers. Pyroxenites are a main contributor to mantle heterogeneity, yet their origin and petrogenesis is still disputed. Highly siderophile elements (HSE: Os, Ir, Ru, Pt, Pd, Re) and the Re-Os isotopic system, which are predominantly controlled by base metal sulfides (BMS), are considered powerful tools to study mantle processes offering a different perspective than conventional lithophile trace elements. To better understand the melt-rock interactions in the lithospheric mantle on an individual grain scale, 22 BMS from two EL pyroxenite samples from Monte Gavi and Rio Strega were analyzed for HSE and 187Os/188Os signatures. The Monte Gavi pyroxenite consists of a coarse-grained matrix of Cpx, Opx, Ol and secondary mica. Base metal sulfides occur as abundant (n=30-40 grains per thin section) large grains (up to 400 μm), systematically associated to mica and adjacent chlorite-filled fractures crosscutting the entire sample. They are Py, Pn and Cpy in close to equal proportions (40%:35%:25%, respectively) frequently intergrown with ilmenite and magnetite. The Rio Strega garnet clinopyroxenite has a fine-grained matrix of Opx, Cpx, Grt, Spl and Plag. Base metal sulfides are as abundant as in the Monte Gavi pyroxenite, smaller in size (50-100 μm) and show a different sulfide assemblage (Po:Pn:Cpy = 55%:25%:20%). They are located at Cpx-Plag grain boundaries showing no association with oxides. In the BMS, HSE concentrations span over two orders of magnitude, ranging from 1 ppb to 5 ppm, showing an overall broad, positive CI-chondrite normalized HSE pattern (Pd/Ir = 29-59; Re/Os = 2-17). Their 187Os/188Os signatures vary from unradiogenic to highly radiogenic (0.1081-0.3745) with one outlier at 1.0062. The pyroxenites, which formed by melt-rock reaction between a silicate melt and a peridotitic protolith, have thus inherited their 187Os/188Os signatures at the grain scale from both the mantle residue and metasomatic agent. Additionally, the BMS are comparatively less radiogenic than the respective bulk pyroxenite (187Os/188Os: 0.6906 for Monte Gavi, 1.0544 for Rio Strega), suggesting that radiogenic Os, and potentially other HSE, are also significantly hosted by platinum group minerals or silicates. Ultimately, this study highlights the necessity of considering not only bulk rock isotopic signatures, but also the mineral scale ones, when studying the heterogeneity of the terrestrial mantl