Strategia progetto e sviluppo tecnologico del portale NADIR - network archeologico di ricerca

The portal NADIR (Network of Archaeological Research) is developed from the work of the \u201cCommission Carandini\u201d of 2009 for the SITAN (Sistema Informativo Territoriale Archeologico Nazionale) and aims to build integration between scienti c information systems and infrastructure of computer networks, the physical locations and the various functional areas of research that are developed at the national level. It aspires to be a cooperative network of shared work between the different databases spread throughout the country

Ab-initio study of model guanine assemblies: The role of pi-pi coupling and band transport

Several assemblies of guanine molecules are investigated by means of first-principle calculations. Such structures include stacked and hydrogen-bonded dimers, as well as vertical columns and planar ribbons, respectively, obtained by periodically replicating the dimers. Our results are in good agreement with experimental data for isolated molecules, isolated dimers, and periodic ribbons. For stacked dimers and columns, the stability is affected by the relative charge distribution of the pi orbitals in adjacent guanine molecules. pi-pi coupling in some stacked columns induces dispersive energy bands, while no dispersion is identified in the planar ribbons along the connections of hydrogen bonds. The implications for different materials comprised of guanine aggregates are discussed. The bandstructure of dispersive configurations may justify a contribution of band transport (Bloch type) in the conduction mechanism of deoxyguanosine fibres, while in DNA-like configurations band transport should be negligible.Comment: 21 pages, 6 figures, 3 tables, to be published in Phys. Rev.

New insights on Celtic migration in Hungary and Italy through the analysis of non-metric dental traits

The Iron Age is characterized by an extended interweaving of movements by Celts in Europe. Several waves of Celts from Western and Central Europe migrated southeast and west from the core area of the La Téne culture (between Bourgogne and Bohemia). Through the analysis of non-metric dental traits, this work aims to understand the biological relationship among Celtic groups arrived in Italy and the Carpathian Basin, as well as between local populations and Celtic newcomers. A total of 10 non-metric dental traits were analyzed to evaluate biological affinities among Celts (Sopron-Krautacker and Pilismarót-Basaharc) and Scythians-related populations from Hungary (Tápiószele), Celts from continental Europe (Switzerland and Austria), two Iron Age Etruscan-Celtic sites from northern Italy (Monterenzio Vecchio and Monte Bibele), 13 Iron Age central-southern Italic necropolises, and the northern Italian Bronze Age necropolis of Scalvinetto. Strontium isotopes were measured on individuals from the necropolis of Monte Bibele to infer their local or non-local origin. Results highlight the existence of statistically significant differences between Celts and autochthonous Italian groups. Celtic groups from Hungary and Italy (i.e., non-local individuals of Monterenzio Vecchio and Monte Bibele) share a similar biological background, supporting the historical records mentioning a common origin for Celts migrated to the eastern and southern borders of today’s Europe. The presence of a supposed Steppean ancestry both in Celts from Hungary and Celts from northern Italy corroborates the hypothesis of the existence of a westward migration of individuals and genes from the Steppe towards northern Italy during the Bronze and Iron Age, which contributed to the biological variability of pre-Celtic and later Celtic populations, respectively. Conversely, individuals from central-southern Italy show an autochthonous pre-Iron Age background. Lastly, this work supports the existence of Celtic migratory routes in northern Italy, as shown by biological and cultural admixture between Celts and Italics living together

THE LINEAR DICHROISM OF CUBIC MOLECULES : DISTORTION AND LOCAL FIELD CONTRIBUTIONS

Le dichroïsme linéaire de W(CO)6, Mo(CO)6 et Cr(CO)6 dissous dans un mélange compensé de dérivés du cholestérol met en évidence la présence des déformations stériques qui peuvent être la cause principale ou secondaire de l'anisotropie optique, l'autre cause étant l'effet des champs diélectriques locaux, l'importance relative des deux facteurs dépendant de la nature des molécules isotropes.The linear dichroism of W(CO)6, Mo(CO)6 and Cr(CO)6 dissolved in an oriented, compensated nematic mixture clearly shows the occurrence of steric deformations which can be the major or minor source of optical anisotropy, together with local dielectric field effects, depending on the nature of the isotropic molecule

Circular dichroism for studying gel-like phases

Chiroptical spectroscopies, optical rotatory dispersion (ORD) and circular dichroism (CD) [1], were developed in the 1960s to study mainly steroidal ketones [2] and octahedral metal complexes [3]. Subsequently, several different chromophores were investigated by CD using different theoretical analyses [4]; the exciton approach, in particular, has been very successful for studying molecular systems containing two or more absorbing chromophores, for example, biaryls [4, 5] and proteins [6]. At the present time, the outstanding sensitivity of CD is employed mainly to study biological macromolecules and their perturbations by external factors. In the field of supramolecular chemistry, CD has several interesting applications. In particular, assembly processes leading to the formation of helical superstructures can be investigated [7]. In those cases where gels are formed by chiral monomers through self-assembly processes, it seems natural to use CD to monitor the progress of the process and, hopefully, to obtain information on the assembled structures that complements that from other techniques (see Chapters 10-12)

The use of CD spectroscopy for the study of the self-assembly of guanine derivatives

Circular dichroism (CD) spectroscopy can be successfully used to study the assembly of homoguanylic and guanosine-rich oligonucleotides. The CD corresponding to the low-energy bands of the guanine spectrum in the 250-290 nm region is mainly determined by exciton interaction between the guanine chromophores; it gives information on the relative skew of G-quartets and on their distortion from the classical structure found in the four-stranded helix of poly(G). The handedness of the sugar-phosphate backbone can be deduced indirectly only if the conformation of the bases around the glycosyl bond is known