346 research outputs found

    Is the Optimal Implementation Inefficient? Elementarily Not

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    Sharing graphs are a local and asynchronous implementation of lambda-calculus beta-reduction (or linear logic proof-net cut-elimination) that avoids useless duplications. Empirical benchmarks suggest that they are one of the most efficient machineries, when one wants to fully exploit the higher-order features of lambda-calculus. However, we still lack confirming grounds with theoretical solidity to dispel uncertainties about the adoption of sharing graphs. Aiming at analysing in detail the worst-case overhead cost of sharing operators, we restrict to the case of elementary and light linear logic, two subsystems with bounded computational complexity of multiplicative exponential linear logic. In these two cases, the bookkeeping component is unnecessary, and sharing graphs are simplified to the so-called "abstract algorithm". By a modular cost comparison over a syntactical simulation, we prove that the overhead of shared reductions is quadratically bounded to cost of the naive implementation, i.e. proof-net reduction. This result generalises and strengthens a previous complexity result, and implies that the price of sharing is negligible, if compared to the obtainable benefits on reductions requiring a large amount of duplication

    Event related potentials reveal that increasing perceptual load leads to increased responses for target stimuli and decreased responses for irrelevant stimuli

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    This Document is Protected by copyright and was first published by Frontiers. All rights reserved. It is reproduced with permission.Peer reviewedPublisher PD

    L’organisation du temps libre : les foyers du soldat en Italie

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    L’Italie entre en guerre le 24 mai 1915, presque dix mois aprĂšs les autres puissances. Auparavant, ni l’armĂ©e ni l’État n’étudient un Ă©ventuel plan d’action pour le temps libre des combattants. Si les autoritĂ©s civiles et militaires Ă©taient pleinement convaincues que la guerre serait de courte durĂ©e, la principale raison de cette carence trouve son origine dans la traditionnelle passivitĂ© des pouvoirs publics en matiĂšre d’assistance aux classes dĂ©favorisĂ©es, y compris concernant leur temps li..

    Wheat Grain Composition, Dough Rheology and Bread Quality as Affected by Nitrogen and Sulfur Fertilization and Seeding Density

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    Flour from old varieties are usually considered very weak flours, and thus difficult to use in breadmaking especially when processed as Italian \u201cTipo 2\u201d flour. Hence, the aim of our study was to understand if agronomic treatments can be used to improve flour processability and the quality of three old wheat varieties. An experimental strip-plot scheme was used: three old wheat varieties (Andriolo, Sieve, Verna), two seeding densities, three levels of nitrogen fertilization (N35, N80, and N135), and two levels of foliar sulfur fertilization. Analyzed parameters related to kernel composition, dough rheology and bread quality. Sulfur and nitrogen treatments significantly affected protein composition and dough alveograph strength, which increased by about 34% with nitrogen fertilization, and by about 14% with the sulfur treatment. However, only nitrogen fertilization affected bread characteristics. Crumb density significantly decreased from N35 to N135, while springiness and cohesiveness increased. On the other hand, sulfur did not improve breads. This highlight the importance of performing breadmaking tests in addition to the rheological determinations. The poor technological performance of old wheat flours can be improved with agronomical treatments designed to obtain higher-quality bread

    PALEOBIOLOGY FROM MUSEUM COLLECTIONS: COMPARING HISTORICAL AND NOVEL DATA ON UPPER MIOCENE MOLLUSCS OF THE LIVORNO HILLS

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    The upper Miocene mollusc collection from Monti Livornesi, Italy, collected more than a century ago, is confronted with new collections coming from the same localities of Popogna and Quarata. The study concerns the comparison of abundance data of three distinct fossil assemblages from the three vertically-stacked stratigraphic units called Luppiano, Rosignano and Raquese, of upper Tortonian-early Messinian age. Literature and museological data allowed to attribute most museum specimens to one and only one fossil assemblage. Museum collections preserve roughly the same dominant species, with similar ranks as the new quantitative field collections. Significant differences are however evident in the Luppiano assemblage from brackish-water, shallow subtidal bottoms, because new samples yield many species of small size, some of which with high dominance, that are completely lacking in museum collections, suggesting a bias due to size sorting and hinting at the overwhelming contribution of small-sized species to global mollusc diversity. On the other hand the Raquese assemblage, from an open marine shelf setting, can be similarly interpreted from the study of either the museum of new collection, yielding a similar species list and rank. The Rosignano mollusc assemblage, from a bioclastic bottom near a coral patch reef and characterised by fossils with a distinct taphonomic signature, is insufficiently represented in both historical and new collections. The systematics of the three assemblages are revised. The study contributes to the growing literature on museum “dark data” by showing that museum collections may yield abundance data significant for paleobiological analysis

    Planck LFI – Test Report on the TMH/TQL (QM and FM) by Using A Known Signal Tests Data

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    Version 1.2 provided as reference document for the Planck SGS Implementation Review (2006)This document describes methods, test procedures and results of the validation of TMH/TQL by using a signal generator. The Flight Model (FM) version of the TMH/TQL includes only bug fixes to the Qualification Model version (found during the QM testing) and a change in the interpretation of the tertiary header of the scientific telemetry packets, due to a modification in the header structure performed by Laben (Alcatel Alenia Space - Milan) in June 2006. Note that the data set acquired to perform the described test is always applied before any release of Operational Model, to validate its correct telemetry handling

    Uncovering the Relationship between Sulphation Patterns and Conformation of Iduronic Acid in Heparan Sulphate

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    The L-iduronic acid (IdoA) residue is a critically important structural component in heparan sulphate polysaccharide for the biological functions. The pyranose ring of IdoA is present in 1C4-chair, 2SO-skew boat, and less frequently, in 4C1-chair conformations. Here, we analyzed the conformation of IdoA residue in eight hexasaccharides by NMR. The data demonstrate a correlation between the conformation of IdoA and sulphations in the surrounding saccharide residues. For the 2-O-sulpho IdoA residue, a high degree of sulphation on neighboring residues drives ring dynamics towards the 2SO-skew boat conformer. In contrast, the nonsulphated IdoA residue is pushed towards the 1C4-chair conformer when the neighboring residues are highly sulphated. Our data suggest that the conformation of IdoA is regulated by the sulphation pattern of nearby saccharides that is genetically controlled by the heparan sulphate biosynthetic pathway

    Introduction to the Molecules Special Edition Entitled 'Heparan Sulfate and Heparin: Challenges and Controversies': Some Outstanding Questions in Heparan Sulfate and Heparin Research

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    The scope of this article is to provide a brief general introduction to heparan sulfate (HS) and heparin, and attempt to identify some of the central challenges regarding research into the chemistry and biology of glycosaminoglycans (GAGs), some of which are the subject of contributions to the special issue of Molecules (published in volume 23, 2018) entitled ‘Heparan Sulfate and Heparin: Challenges and Controversies’ [...

    Nuclear Magnetic Resonance and Molecular Dynamics Simulation of the Interaction between Recognition Protein H7 of the Novel Influenza Virus H7N9 and Glycan Cell Surface Receptors

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    Avian influenza A viruses, which can also propagate between humans, present serious pandemic threats, particularly in Asia. The specificity (selectivity) of interactions between the recognition protein hemagglutinin (HA) of the virus capsid and the glycoconjugates of host cells also contributes to the efficient spread of the virus by aerosol between humans. Some avian origin viruses, such as H1N1 (South Carolina 1918), have improved their selectivity for human receptors by mutation in the HA receptor binding site, to generate pandemic viruses. Molecular details and dynamics of glycan–HA interactions are of interest, both in predicting the pandemic potential of a new emerging strain and in searching for new antiviral drugs. Two complementary techniques, <sup>1</sup>H saturation transfer difference (<sup>1</sup>H STD) nuclear magnetic resonance and molecular dynamics (MD) simulation, were applied to analyze the interaction of the new H7 (A/Anhui/1/13 H7N9) with LSTa [Neu5Ac α(2→3) Gal ÎČ(1→3) GlcNAc ÎČ(1→3) Gal ÎČ(1→4) Glc] and LSTc [Neu5Ac α(2→6) Gal ÎČ(1→4) GlcNAc ÎČ(1→3) Gal ÎČ(1→4) Glc] pentasaccharides, models of avian and human receptor glycans. Their interactions with H7 were analyzed for the first time using <sup>1</sup>H STD and MD, revealing structural and dynamic behavior that could not be obtained from crystal structures, and contributing to glycan–HA specificity. This highlighted aspects that could affect glycan–HA recognition, including the mutation H7 G228S, which increases H2 and H3 specificity for the human receptor. Finally, interactions between LSTc and H7 were compared with those between LSTc and H1 of H1N1 (South Carolina 1918), contributing to our understanding of the recognition ability of HAs
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