Origin of arsenic pollution in Southwest Tuscany: comparison of fluvial sediments

The Colline Metallifere in SW Tuscany are characterized by strong anomalies in arsenic concentrations and distribution. The area is sparsely populated and largely wild, though it has been subject to human impact due to mining and metal processing since Etruscan and Roman times. In the Middle Ages it was exploited intensively for silver and copper. Until 1995, pyrite (FeS2) was mined and roasted to produce sulphuric acid and iron. Hypotheses based on geological and mineralogical factors formulated in the last 20 years have failed to explain the peculiar distribution of arsenic in the Colline Metallifere. Here we report preliminary results of widespread sampling and analysis of the fluvial sediments of rivers originating in this mining area. The data was analysed in relation to the archaeological features of the area, since the presence of ancient mining and ore processing sites can shed light on the peculiar distribution of arsenic. Comparison of data from two rivers and their respective contaminated and uncontaminated coastal lagoons also clarified the general mechanisms of arsenic mobility, pinpointing the source of arsenic contamination. The study methods also promise to be useful for discovering unknown archaeological sites.     

Sull’integrazione frazionaria anisotropa

Riassunto In questa nota si indica il tipo della singolarità nell'origine della trasformata di Fourier di certe funzioni; mediante, tale risultato si possono rapidamente ritrovare alcune maggiorazioni circa i nuclei di integrazione frazionaria anisotropa già stabiliti daP. I. Lizorkin.

---

Summary In this paper the form of the singularity near the origine of the Fourier trasform of certain functions is shown; with the aid of this result some estimates for the kernel of non-isotropic fractional integration previously proved byP. I. Lizorkin are established in a very simple way.

     

The variability of composition of the volatile fraction of olive oil

Aroma of olive oil is a very complex mixture of components. Analysis of head space of a series of virgin olive oil samples indicate a great variability of volatile substances composition in olives and these data probably should be related to the story of olives after collecting.     

Dehydroindigo: a new piece into the Maya Blue puzzle from the voltammetry of microparticles approach

Combining a novel technique, the voltammetry of microparticles, with spectrometric, nuclear magnetic resonance, electron microscopy, and atomic force microscopy data, Maya Blue is detected in wall paintings of the Substructures A-3, A-5, and A-6, dated in the Early Classical period (440-450 a.c.), and the Substructure II-C, dated in the Late Preclassical period (150 b.C.), in the archaeological site of Calakmul (Campeche, Mexico), thus providing evidence on the use of the pigment 750 years prior to the date currently accepted. Electrochemical measurements, supported by spectrometric data, indicate that the presence of palygorskite-attached dehydroindigo, the oxidized form of indigo, contributes to the greenish color of Maya Blue. Enthalpy and entropy of attachment of such compounds to palygorskite are calculated from the temperature dependence of electrochemical data. Both attachment processes are endothermic, becoming thermodynamically spontaneous at moderate temperatures. Accordingly, ancient Mayas may modulate the hue of Maya Blue from turquoise to greenish blue by controlling the temperature during the crushing process.     

High-performance liquid chromatography and capillary electrophoresis for the analysis of maize proteins

Methods for the analysis of maize proteins using HPLC and CE are reviewed. Most of the references cited in this review concern HPLC methods. Size-exclusion HPLC and especially RP-HPLC methods have been developed for characterization of normal and genetically modified maize, cultivar differentiation, and prediction of quality. Few CE methods for the analysis of maize proteins were found in the existing literature. Most of these methods focus on optimization of the separation of maize proteins using CZE and SDS-capillary gel electrophoresis.     

Fractional diffusion-type equations with exponential and logarithmic differential operators

We deal with some extensions of the space-fractional diffusion equation, which is satisfied by the density of a stable process (see Mainardi et al. (2001)): the first equation considered here is obtained by adding an exponential differential (or shift) operator expressed in terms of the Riesz–Feller derivative. We prove that this produces a random component in the time-argument of the corresponding stable process, which is represented by the so-called Poisson process with drift. Analogously, if we add, to the space-fractional diffusion equation, a logarithmic differential operator involving the Riesz-derivative, we obtain, as a solution, the transition semigroup of a stable process subordinated by an independent gamma subordinator with drift. Finally, we show that an extension of the space-fractional diffusion equation, containing both the fractional shift operator and the Feller integral, is satisfied by the transition density of the process obtained by time-changing the stable process with an independent linear birth process with drift.     

Vanishing and cocentralizing generalized derivations on Lie ideals

Let R be a prime ring of characteristic different from 2, U its right Utumi quotient ring, C its extended centroid and L a not central Lie ideal of R. Suppose that F, G and H are generalized derivations of R, with F≠0, such that F(G(x)x?xH(x)) = 0, for any x∈L. In this paper we describe all possible forms of F, G and H.     

When do linear combinations of orthogonal polynomials yield new sequences of orthogonal polynomials?

Given {P_n}_n≥0 a sequence of monic orthogonal polynomials, we analyze their linear combinations with constant coefficients and fixed length, i.e., 

     

Large Amplitude Motions of Pyruvic Acid (CH3-CO-COOH)

Torsional and rotational spectroscopic properties of pyruvic acid are determined using highly correlated ab initio methods and combining two different theoretical approaches: Second order perturbation theory and a variational procedure in three-dimensions. Four equilibrium geometries of pyruvic acid, Tc, Tt, Ct, and CC, outcome from a search with CCSD(T)-F12. All of them can be classified in the C_s point group. The variational calculations are performed considering the three internal rotation modes responsible for the non-rigidity as independent coordinates. More than 50 torsional energy levels (including torsional subcomponents) are localized in the 406–986 cm⁻¹ region and represent excitations of the ν₂₄ (skeletal torsion) and the ν₂₃ (methyl torsion) modes. The third independent variable, the OH torsion, interacts strongly with ν₂₃. The A₁/E splitting of the ground vibrational state has been evaluated to be 0.024 cm⁻¹ as it was expected given the high of the methyl torsional barrier (338 cm⁻¹). A very good agreement with respect to previous experimental data concerning fundamental frequencies (ν^CAL − ν^EXP ~ 1 cm⁻¹), and rotational parameters (B₀^CAL − B₀^EXP < 5 MHz), is obtained.