15,603 research outputs found

    IFLA Congress in Italy for the fourth time , Libraries create futures: building on cultural heritage : final programme, Milan, Italy, 23-27 August 2009

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    Welcome of the Chair of the Italian National Committee. IFLA Congress comes back to Italy for the fourth time: 1929, 1951, 1964, and now 2009. In June 1929, in the Marciana Library (Venice), Mr. Isak Collijn announced the name of the Library Federation, and the Italian librarian Vincenzo Fago read the Statute, dated "Florence, June 25, 1929": 1) The name of this organization shall be the International Federation of Library Associations. 2) The object of the Federation shall be to promote international library cooperation. One year after, in 1930, the Italian Library Association (AIB) was founded

    A Coding Theoretic Study on MLL proof nets

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    Coding theory is very useful for real world applications. A notable example is digital television. Basically, coding theory is to study a way of detecting and/or correcting data that may be true or false. Moreover coding theory is an area of mathematics, in which there is an interplay between many branches of mathematics, e.g., abstract algebra, combinatorics, discrete geometry, information theory, etc. In this paper we propose a novel approach for analyzing proof nets of Multiplicative Linear Logic (MLL) by coding theory. We define families of proof structures and introduce a metric space for each family. In each family, 1. an MLL proof net is a true code element; 2. a proof structure that is not an MLL proof net is a false (or corrupted) code element. The definition of our metrics reflects the duality of the multiplicative connectives elegantly. In this paper we show that in the framework one error-detecting is possible but one error-correcting not. Our proof of the impossibility of one error-correcting is interesting in the sense that a proof theoretical property is proved using a graph theoretical argument. In addition, we show that affine logic and MLL + MIX are not appropriate for this framework. That explains why MLL is better than such similar logics.Comment: minor modification

    Towards a network government? A critical analysis of current assessment methods for e-government

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    Contemporary public administrations have become increasingly more complex, having to cordinate actions with emerging actors in the public and the private spheres. In this scenario the modern ICTs have begun to be seen as an ideal vehicle to resolve some of the problems of public administration. We argue that there is a clear need to explore the extent to which public administrations are undergoing a process of transformation towards a netowork government linked to the systematic incorporation of ICTs in their basic activities. Through critically analysing a selection of e-government evaluation reports, we conclude that research should be carried out if we are to build a solid government assessment framework based on network-like organisation characteristics

    Determination of plasmid copy number in yeast transformants by means of agarose plugs

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    The determination of plasmid copy number in Saccharomyces cerevisiaetransformants containing circular or linear plasmids is currently performed with total yeast DNA extracts obtained from cultures grown under selection. The determination is based essentially on quantitative Southern hybridization of an appropirate probe to a sequence present both on plasmid and chromosomal DNA in digested or undigested samples run out on conventional agarose gels. The DNA extraction procedure calls for treatment of cell lysates with organic solvents that could entail systemic losses of eithr plasmid or chromosomal DNA thus producing artifactual results. We propose here a method based on the assumption that quantitative analysis of plasmid and chromosomal DNA extracted from yeast cells embedded in agarose plugs will furnish more reliable results. With this procedure the cells are lysed in situ, thus avoiding possible losses of material, and the chromosomes and plasmid DNAs, trapped within the agarose matrix, can be separated by pulse field electrophoresis

    Enumerating five families of pattern-avoiding inversion sequences; and introducing the powered Catalan numbers

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    The first problem addressed by this article is the enumeration of some families of pattern-avoiding inversion sequences. We solve some enumerative conjectures left open by the foundational work on the topics by Corteel et al., some of these being also solved independently by Lin, and Kim and Lin. The strength of our approach is its robustness: we enumerate four families F1F2F3F4F_1 \subset F_2 \subset F_3 \subset F_4 of pattern-avoiding inversion sequences ordered by inclusion using the same approach. More precisely, we provide a generating tree (with associated succession rule) for each family FiF_i which generalizes the one for the family Fi1F_{i-1}. The second topic of the paper is the enumeration of a fifth family F5F_5 of pattern-avoiding inversion sequences (containing F4F_4). This enumeration is also solved \emph{via} a succession rule, which however does not generalize the one for F4F_4. The associated enumeration sequence, which we call the \emph{powered Catalan numbers}, is quite intriguing, and further investigated. We provide two different succession rules for it, denoted ΩpCat\Omega_{pCat} and Ωsteady\Omega_{steady}, and show that they define two types of families enumerated by powered Catalan numbers. Among such families, we introduce the \emph{steady paths}, which are naturally associated with Ωsteady\Omega_{steady}. They allow us to bridge the gap between the two types of families enumerated by powered Catalan numbers: indeed, we provide a size-preserving bijection between steady paths and valley-marked Dyck paths (which are naturally associated with ΩpCat\Omega_{pCat}). Along the way, we provide several nice connections to families of permutations defined by the avoidance of vincular patterns, and some enumerative conjectures.Comment: V2 includes modifications suggested by referees (in particular, a much shorter Section 3, to account for arXiv:1706.07213

    Quantifying the Plasmonic Character of Optical Excitations in a Molecular J-Aggregate

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    The definition of plasmon at the microscopic scale is far from being understood. Yet, it is very important to recognize plasmonic features in optical excitations, as they can inspire new applications and trigger new discoveries by analogy with the rich phenomenology of metal nanoparticle plasmons. Recently, the concepts of plasmonicity index and the generalized plasmonicity index (GPI) have been devised as computational tools to quantify the plasmonic nature of optical excitations. The question may arise whether any strong absorption band, possibly with some sort of collective character in its microscopic origin, shares the status of plasmon. Here we demonstrate that this is not always the case, by considering a well-known class of systems represented by J-aggregates molecular crystals, characterized by the intense J band of absorption. By means of first-principles simulations, based on a many-body perturbation theory formalism, we investigate the optical properties of a J-aggregate made of push-pull organic dyes. We show that the effect of aggregation is to lower the GPI associated with the J-band with respect to the isolated dye one, which corresponds to a nonplasmonic character of the electronic excitations. In order to rationalize our finding, we then propose a simplified one-dimensional theoretical model of the J-aggregate. A useful microscopic picture of what discriminates a collective molecular crystal excitation from a plasmon is eventually obtained.Comment: Published by ACS under ACS AuthorChoice licens
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