Essential oils: SPE fractionation

Summary Essential oil analysis is often characterised by mixtures that are difficult to separate. The components belong to different classes of compounds that range widely in concentration. Hence, a pre-separation technique is often required, at least to evaluate the minor components. This paper reports an SPE method to overcome this problem. The method was developed with a standard solution that yielded 90% mean recovery of the analytes. It was then tested on two different essential oils: tarragon (Artemisia dracunculus) and rose (Rosa damascena). In this way, the essential oil components were pre-separated into three fractions: A, which contained hydrocarbons; B, which contained esters, ethers, oxides, carbonyl compounds and tertiary alcohols; and C, which contained other alcohols, acids and diols.     

Riferimenti isotropi in relatività generale

We consider anew approach for a relativistic frame of reference in the polar sense [1] (two-congruences) and the related non-holonomic techniques for anull congruence (light flux); 1° order characteristic tensors, Ricci rotation coefficients, longitudinal and transversal covariant derivatives are deduced in general form. Thus, the method of a standard frame of reference is extended to thenull case.

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Sunto Si consideraun nuovo approccio per un sistema di riferimento relativistico nel senso polare [1] (bicongruenza), adattando le tecniche non-olonome connesse al caso in cuiuna delle due congruenze sia nulla (flusso di luce); si derivano, in forma generale, i tensori caratteristici del 1° ordine, i coefficienti di rotazione di Ricci, le derivate covarianti longitudinali e trasversali. I metodi dei sistemi di riferimento standard vengono così estesi alcaso nullo, determinando unaalternativa tensoriale al cosidetto metodo (non reale) delle tetradi nulle [15].

     

Techniques for resveratrol silylation

Summary Resveratrol, a wine stilbene phytoalexin with some pharmacological properties, was extracted from red wines by MeOH elution of a Sephadex LH-20 column, used for its purification. The column extract was dried and silylated by different methods to optimize resveratrol derivatization. The resveratrol analysis was by gas chromatography and gas cromatography-mass spectrometry allowing determination of its two isomers.     

The mathematical theory of endosymbiosis I

This work presents a new model of the evolutionary process formulated by the Serial Endosymbiosis Theory represented by a succession of stages involving different metabolic and ecological interactions among populations of bacteria considering both the population dynamics and production processes of these populations. In such an approach we make use of systems of differential equations known as Volterra–Hamilton systems as well as some geometric concepts involving KCC Theory and the Projective Geometry of Berwald Spaces and also correct a statement of M. Matsumoto in the literature on this topic. We also recount in some detail previous work comparing production stability of Endosymbiosis Theory with that of Ancestral Commune Theory.     

Calibrated American option pricing by stochastic linear programming

Abstract

We propose an approach for computing the arbitrage-free interval for the price of an American option in discrete incomplete market models via linear programming. The main idea is built replicating strategies that use both the basic asset and some European derivatives available on the market for trading. This method goes under the name of calibrated option pricing and it has given significant results for European options. Here, we extend the analysis to American options showing that the arbitrage-free interval can be characterized in terms of martingale measures and that it gets significantly reduced with respect to the non-calibrated case.     

Deposition of SiOx layer by plasma-enhanced chemical vapor deposition for the protection of silver (Ag) surfaces

Silver surfaces have been treated with plasma-enhanced chemical vapor deposition to produce SiO₂-like coatings for possible applications in the jewelry industry. Different experimental conditions have been tested in order to optimize the protective effectiveness of the deposited layers. Samples were analyzed with optical and scanning electron microscopy and energy-dispersive spectrometry.     

Chaos Encrypted Optical Communication System

Abstract

In this article, we report on the research activity that has been recently carried out in Italy on secure transmission by using chaotic carriers in the framework of a national and two international projects. Transmission of both analog and digital signals has been demonstrated, as well as theoretically and numerically investigated. Close-loop digital transmission over 100 km distance has been achieved for the first time.     

An efficient multi-objective evolutionary fuzzy system for regression problems

During the last years, multi-objective evolutionary algorithms (MOEAs) have been extensively employed as optimization tools for generating fuzzy rule-based systems (FRBSs) with different trade-offs between accuracy and interpretability from data. Since the size of the search space and the computational cost of the fitness evaluation depend on the number of input variables and instances, respectively, managing high-dimensional and large datasets is a critical issue.In this paper, we focus on MOEAs applied to learn concurrently the rule base and the data base of Mamdani FRBSs and propose to tackle the issue by exploiting the synergy between two different techniques. The first technique is based on a novel method which reduces the search space by learning rules not from scratch, but rather from a heuristically generated rule base. The second technique performs an instance selection by exploiting a co-evolutionary approach where cyclically a genetic algorithm evolves a reduced training set which is used in the evolution of the MOEA.The effectiveness of the synergy has been tested on twelve datasets. Using non-parametric statistical tests we show that, although achieving statistically equivalent solutions, the adoption of this synergy allows saving up to 97.38% of the execution time with respect to a state-of-the-art multi-objective evolutionary approach which learns rules from scratch.     

An integrated Raman and petrographic characterization of Italian mediaeval artifacts in pietra ollare (soapstone)

Ten fragments of pots made by pietra ollare (basic and ultrabasic metamorphic rocks belonging to greenschist facies) found in the archaeological site of Crocetta di Sant'Agata Bolognese (Bologna, Italy) have been studied to characterize them and to define their provenance. The fragments, dated between the 9^th and 10^th century AD, show traces of blackening from fire, indicating the use of these findings as pots by fire. The extensive use of a non‐destructive technique, Raman spectroscopy, in both laboratory and portable forms, for the provenance analysis of pietra ollare artifacts has been evaluated. Micro‐Raman spectroscopy was used for a detailed study of the main components, to identify the secondary minerals and to study the distribution of the mineral phases in the samples. The samples show schistose texture, are fine grained and consist mainly of talc and chlorite, and subordinate carbonates, oxides and serpentine. Olivine is rare. Based on the mineralogical composition, the material can be defined as chlorite and carbonate talc‐schist. Our samples of pietra ollare may be assigned to chlorite and magnesite‐bearing talc‐schists. The alpine areas of origin of this lithotype are Valtellina, Valchiavenna and Val Bregaglia. In particular, we can hypothesize that the origin of these findings is Valchiavenna, which had great commercial importance in the Middle Ages. Further measurements, obtained with a portable Raman spectrometer, directly on a quarry near Chiavenna, support our hypothesis. Copyright © 2013 John Wiley & Sons, Ltd.     

Learning concurrently partition granularities and rule bases of Mamdani fuzzy systems in a multi-objective evolutionary framework

In this paper we propose a multi-objective evolutionary algorithm to generate Mamdani fuzzy rule-based systems with different good trade-offs between complexity and accuracy. The main novelty of the algorithm is that both rule base and granularity of the uniform partitions defined on the input and output variables are learned concurrently. To this aim, we introduce the concepts of virtual and concrete rule bases: the former is defined on linguistic variables, all partitioned with a fixed maximum number of fuzzy sets, while the latter takes into account, for each variable, a number of fuzzy sets as determined by the specific partition granularity of that variable. We exploit a chromosome composed of two parts, which codify the variables partition granularities, and the virtual rule base, respectively. Genetic operators manage virtual rule bases, whereas fitness evaluation relies on an appropriate mapping strategy between virtual and concrete rule bases. The algorithm has been tested on two real-world regression problems showing very promising results.