A Fluctuation-Dissipation Process without Time Scale

We study the influence of a dissipation process on diffusion dynamics triggered by fluctuations with long-range correlations. We make the assumption that the perturbation process involved is of the same kind as those recently studied numerically and theoretically, with a good agreement between theory and numerical treatment. As a result of this assumption the equilibrium distribution departs from the ordinary canonical distribution. The distribution tails are truncated, the distribution border is signalled by sharp peaks and, in the weak dissipation limit, the central distribution body becomes identical to a truncated Levy distribution.Comment: REVTeX 3.1, 7 pages, 2 EPS figures, uses epsfig.sty. Submitted to Phys. Rev.

Topography and structural heterogeneities in surface ground deformation: a simulation test for Somma-Vesuvius volcano

Abstract. We simulate the deformation of Somma-Vesuvius volcano due to some overpressure sources by means of a finite element 3D code. The main goal of these simulations is to investigate the influence of topography and structural heterogeneity on ground deformation. In our model the sources of deformation are embedded in an elastic linear isotropic medium and located at various depths. Geometry (shape and lateral extension) of the sources is mainly constrained by the results coming from recent seismic tomography studies. The structural heterogeneity has been modelled in terms of dynamic elastic parameters (Young's modulus) retrieved from previous seismic tomography and gravity studies. A high-resolution digital terrain model is used for the topography of the volcano subaerial edifice. Evidences from our results suggest that real topography and structural heterogeneities are key factors governing the ground deformation, which often turns being one of the most relevant problems in volcano monitoring. A large deviation from the axially symmetrical model of the displacement field is the main result of our modelling. Such an asymmetry is routinely unaccounted for when Mogi's simplistic modelling in a homogeneous medium with simplified topography is used. Our study clearly demonstrate that a better knowledge of deformation patterns can significantly help in the location of monitoring sensors as well as in the design of an efficient geodetic network

The Neuquén composite section: magnetostratigraphy and biostratigraphy of the marine lower Jurassic from the Neuquén basin (Argentina)

Paleomagnetic and biostratigraphic data from five marine sedimentary sections in the Argentine Neuquén basin have allowed to construct the Lower Jurassic Neuquén Composite Section. This composite section comprises 14 reversed and 11 normal polarity Zones, in relation to 17 Andean ammonite Assemblage Zones, spanning the Hettangian^Toarcian (Early Jurassic). It represents the first paleomagnetic data of Lower Jurassic marine successions in the Southern Hemisphere. The Neuquén composite Section was correlated to the International Mesozoic Polarity Time Scale which, for the Lower Jurassic, comprises 54 polarity Zones and 16 Standard ammonite Zones. The correlation between the regional and the international biomagnetostratigraphic scales supports but also refines the correlation between the Andean and Standard ammonite zonations. Correlation between the Neuquén composite Section and the polarity sequences recorded in each section helped to assign several unfossiliferous stratigraphical levels to the corresponding biozones.Facultad de Ciencias Naturales y Muse

The Neuquén composite section: magnetostratigraphy and biostratigraphy of the marine lower Jurassic from the Neuquén basin (Argentina)

Paleomagnetic and biostratigraphic data from five marine sedimentary sections in the Argentine Neuquén basin have allowed to construct the Lower Jurassic Neuquén Composite Section. This composite section comprises 14 reversed and 11 normal polarity Zones, in relation to 17 Andean ammonite Assemblage Zones, spanning the Hettangian^Toarcian (Early Jurassic). It represents the first paleomagnetic data of Lower Jurassic marine successions in the Southern Hemisphere. The Neuquén composite Section was correlated to the International Mesozoic Polarity Time Scale which, for the Lower Jurassic, comprises 54 polarity Zones and 16 Standard ammonite Zones. The correlation between the regional and the international biomagnetostratigraphic scales supports but also refines the correlation between the Andean and Standard ammonite zonations. Correlation between the Neuquén composite Section and the polarity sequences recorded in each section helped to assign several unfossiliferous stratigraphical levels to the corresponding biozones.Facultad de Ciencias Naturales y Muse

The Neuquén composite section: magnetostratigraphy and biostratigraphy of the marine lower Jurassic from the Neuquén basin (Argentina)

Paleomagnetic and biostratigraphic data from five marine sedimentary sections in the Argentine Neuquén basin have allowed to construct the Lower Jurassic Neuquén Composite Section. This composite section comprises 14 reversed and 11 normal polarity Zones, in relation to 17 Andean ammonite Assemblage Zones, spanning the Hettangian^Toarcian (Early Jurassic). It represents the first paleomagnetic data of Lower Jurassic marine successions in the Southern Hemisphere. The Neuquén composite Section was correlated to the International Mesozoic Polarity Time Scale which, for the Lower Jurassic, comprises 54 polarity Zones and 16 Standard ammonite Zones. The correlation between the regional and the international biomagnetostratigraphic scales supports but also refines the correlation between the Andean and Standard ammonite zonations. Correlation between the Neuquén composite Section and the polarity sequences recorded in each section helped to assign several unfossiliferous stratigraphical levels to the corresponding biozones.Facultad de Ciencias Naturales y Muse

Acoustic plasmons in extrinsic free-standing graphene

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence.An acoustic plasmon is predicted to occur, in addition to the conventional two-dimensional (2D) plasmon, as the collective motion of a system of two types of electronic carriers coexisting in the same 2D band of extrinsic (doped or gated) graphene. The origin of this novel mode stems from the anisotropy present in the graphene band structure near the Dirac points K and K'. This anisotropy allows for the coexistence of carriers moving with two distinct Fermi velocities along the γK and γK' directions, which leads to two modes of collective oscillation: one mode in which the two types of carriers oscillate in phase with one another (this is the conventional 2D graphene plasmon, which at long wavelengths (q → 0) has the same dispersion, q1/2, as the conventional 2D plasmon of a 2D free electron gas), and the other mode found here corresponds to a low-frequency acoustic oscillation (whose energy exhibits at long-wavelengths a linear dependence on the 2D wavenumber q) in which the two types of carriers oscillate out of phase. This prediction represents a realization of acoustic plasmons originated in the collective motion of a system of two types of carriers coexisting within the same band. © 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.MP acknowledges the financial support of MIUR (FIRB-Futuro in Ricerca 2010—Project PLASMOGRAPH grant no. RBFR10M5BT), the European Commission, the European Social Fund and Regione Calabria, (POR) Calabria—FSE 2007/2013. VMS acknowledges financial support from the Spanish MICINN (no. FIS2010-19609-C02-01), the Departamento de Educación del Gobierno Vasco, and the University of the Basque Country (no. GIC07-IT-366-07).Peer Reviewe

Il Grano di Pietro Gaudenzi. Stato di conservazione e problematiche di intervento

L\u2019opera Il grano (\u201cdipinto murale su intonaco applicato a masonite\u201d, cm 249x434, Pinacoteca del Museo Civico \u201cAla Ponzone\u201d di Cremona) viene realizzata da Pietro Gaudenzi nel 1940 per la seconda edizione del Premio Cremona istituito da Roberto Farinacci nel 1939, a seguito della necessit\ue0 di rafforzare il mercato e le quotazioni d\u2019arte attraverso mostre e premi che richiamassero i valori dell\u2019ideologia fascista in campo artistico. I cartoni preparatori degli affreschi eseguiti da Gaudenzi a Rodi, raccolti nella recente mostra (2015) Pietro Gaudenzi: gli affreschi perduti del Castello dei Cavalieri a Rodi [1], ritenuti l\u2019ultima testimonianza rimasta delle pitture murali che occupavano la Sala del pane e la Sala della famiglia del Castello - ricostruito dagli italiani dal 1936 al 1940 - evocano il trittico che vincer\ue0 il premio Cremona nel 1940. Diversamente dalle tecniche sperimentali che hanno caratterizzato molte delle opere del ritorno alla tradizione decorativa murale, Gaudenzi dipinge il trittico su un intonaco composto da un aggregato silicatico e calce. Il disegno \ue8 stato eseguito tramite incisioni dirette da cartoni preparatori, successivamente ripassate con un tratto bruno, i colori sono stati scelti tra quelli tradizionalmente usati per questo tipo di pittura, unitamente a pigmenti inorganici minerali sintetici in uso a partire dal XIX secolo. L\u2019opera, realizzata su pannelli rigidi (masonite), risulta \u2013 sul fondo \u2013 impermeabile al vapore acqueo che, in situazioni di variazione dei parametri microclimatici ambientali e a causa delle frequenti movimentazioni del dipinto, provoca sollevamenti localizzati di forme tondeggianti (a bolla). La pellicola pittorica, resa leggermente plastica dalla vernice, si rigonfia distaccandosi dal supporto in quantit\ue0 talvolta, estese. I conseguenti necessari interventi di manutenzione, mirati al consolidamento dei sollevamenti, risultano particolarmente complessi per l\u2019impossibilit\ue0 di intervenire dal retro: la necessit\ue0 di attraversare il film protettivo e penetrare la pellicola pittorica in assenza di crettature ha evidenziato l\u2019estrema fragilit\ue0 sia del film pittorico che della materia sottostante. Lo studio presenta alcune metodologie di intervento utilizzate, nel tempo, per consolidare il trittico. La possibilit\ue0 di poter analizzare alcuni microframmenti ha richiesto l\u2019applicazione di una strategia analitica basata sull\u2019uso di microscopi e microsonde. La successione degli strati tecnici \ue8 stata definita in microscopia ottica (OM) ed elettronica a scansione (SEM), su \u201ccross section\u201d. Le tessiture e la composizione chimica dei leganti e dei pigmenti dei singoli strati sono state determinate utilizzando un sistema di microanalisi in dispersione di energia (EDS) e in spettrofotometria FT-IR. Questi dati integrano le informazioni ottenute con le tecniche non invasive d\u2019immagine (luminescenza UV, riflettografia IR e riprese IR in falso colore) e puntuali (XRF) realizzate in situ

Monitoring alkylphenols in water using the polar organic chemical integrative sampler (POCIS): determining sampling rates via the extraction of PES membranes and Oasis beads

Polar organic chemical integrative samplers (POCIS) have previously been used to monitor alkylphenol (AP) contamination in water and produced water. However, only the sorbent receiving phase of the POCIS (Oasis beads) is traditionally analyzed, thus limiting the use of POCIS for monitoring a range of APs with varying hydrophobicity. Here a “pharmaceutical” POCIS was calibrated in the laboratory using a static renewal setup for APs (from 2-ethylphenol to 4-n-nonylphenol) with varying hydrophobicity (log Kow between 2.47 and 5.76). The POCIS sampler was calibrated over its 28 day integrative regime and sampling rates (Rs) were determined. Uptake was shown to be a function of AP hydrophobicity where compounds with log Kow < 4 were preferentially accumulated in Oasis beads, and compounds with log Kow > 5 were preferentially accumulated in the PES membranes. A lag phase (over a 24 h period) before uptake in to the PES membranes occurred was evident. This work demonstrates that the analysis of both POCIS phases is vital in order to correctly determine environmentally relevant concentrations owing to the fact that for APs with log Kow ≤ 4 uptake, to the PES membranes and the Oasis beads, involves different processes compared to APs with log Kow ≥ 4. The extraction of both the POCIS matrices is thus recommended in order to assess the concentration of hydrophobic APs (log Kow ≥ 4), as well as hydrophilic APs, most effectively. © 2017 Elsevier Lt