1,522 research outputs found

    Chromosome 1p13 genetic variants antagonize the risk of myocardial infarction associated with high ApoB serum levels

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    PMCID: PMC3480949This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

    A cerebral bridge from olfactory cognition to spatial navigation

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    An evolutionary paradox is the variability of the olfactory bulb size, in contrast to the other brain regions, which are sized proportionally to the peripheral function. This variability seems to be the result of selection for the olfactory function. This disagreement may derive from considering smell as a sense linked to odorous discrimination. In many vertebrates and in terrestrial and marine mammals, the sense of smell has evolved into functions related to the eco-localization. So, if the olfactory function involves spatial perception and navigation, this, couldexplain the proportional discrepancy between the olfactory bulb and olfactory cortex. Humans are able to discriminate a spatial position as a function of olfactory cues. Vice versa, in neurodegenerative syndromes the orientation capacity and olfactory perception are impaired. This leads us to think that could be a common cross-modal processing, of phylogenetic origin, which links olfactory perception and spatial orientation. Starting from these theoretical assumptions, we conducted a basic research, on 100 healthy subjects, investigating, through both behavioral and electroencephalographic data, the connection between spatial memory span and olfactory spatial memory span. Subjects were assessed through a three-condition task: normal Corsi Block Test (CBT), ‘Olfactory’ Block Test (OBT) and a ‘Semantic-Olfactory’ Block Test (SOBT). CBT consisted in a test on spatial memory span; OBT consisted in a presentation a spatial sequences of 9 different odorants (i.e., Eucalyptol, Carvone, Eugenol, Isoamyl Acetate, Geraniol, Phenethyl Alcohol, Acetophenone, Cinnamon, Hexanal) instilled on paper square not recognizable by any sign, positioned on a CBT, and showed in a spatial navigation way, and SOBT consisted of a semantic labelled of olfactory spatial navigation. A GLM repeated measure highlighted significant differences during the three conditions. Subjects had different SPANs due to different conditions. The Semantic olfactory memory SPAN was inferior respect Olfactory span and Spatial Span. Furthermore was found a significant positive correlation between the three condition. The 5 subjects with higher SPAN scores, 5 with medium scores and the 5 subjects with lower SPAN scores were recruited to investigate ERP components elicited during the cross-modal task. Subjects had to perform, during a high-density EEG recording, an olfactory task (administered through the device US2017127971 (A1) “? 2017-05-11), an EEG Posner spatial cueing task and a go/no-go olfactory semantic categorization task. The results of this study will be discussed in light of a theoretical connection between these three aspects of cortical functions that seem strongly interconnected

    Updates on the bryophyte flora of the lowland Woods and temporary ponds west of Lake Trasimeno (Central Italy).

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    A study of the bryophytes of the lowlands west of Lake Trasimeno, a very peculiar territory for its geological, biogeographical and bioclimatic traits, was carried out. The data here reported were collected in a mosaic of woods and Mediterranean temporary ponds, the latter indicated as priority natural habitats under the Habitats Directive 92/43/EEC with the code 3170*. Research led to the identification of 44 taxa of bryophytes (13 liverworts and 31 mosses), among which 5 liverwort and 8 moss species are new records for the Umbria region, while one is confirmed. Particularly interesting is the presence of 13 liverwort taxa considered, according to the European Committee for Conservation of Bryophytes (ECCB), under threat at different levels in Europe. The study offers new outcomes on neglected aspects of the flora of central Italy and represents a considerable improvement of the floristic, biogeographical and ecological understanding of its bryophytic component

    Decidable Fragments of LTLf Modulo Theories

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    We study Linear Temporal Logic Modulo Theories over Finite Traces (LTLMTf), a recently introduced extension of LTL over finite traces (LTLf) where propositions are replaced by first-order formulas and where first-order variables referring to different time points can be compared. In general, LTLMTf was shown to be semi-decidable for any decidable first-order theory (e.g., linear arithmetics), with a tableau-based semi-decision procedure. In this paper we present a sound and complete pruning rule for the LTLMTf tableau. We show that for any LTLMTf formula that satisfies an abstract, semantic condition, that we call finite memory, the tableau augmented with the new rule is also guaranteed to terminate. Last but not least, this technique allows us to establish novel decidability results for the satisfiability of several fragments of LTLMTf, as well as to give new decidability proofs for classes that are already known

    Bryophytic vegetation of fragile and threatened ecosystems: the case of the Mediterranean temporary ponds in inland Central Italy.

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    The first overview of the bryophytic vegetation of the Mediterranean temporary ponds in Umbria region is reported. Phytosociological relevés were carried out in a scattered system of ephemeral pools, where seasonal fluctuation in the water level is the main driving factor. By applying Braun-Blanquet's approach to sample the bryo-communities and multivariate analysis tools to analyse data, the identification of some bryophyte communities was possible, one of which is here described as new association. It is Entosthodono fascicularidis-Archidietum alternifolii ass. nova, referable to the class Psoretea decipientis. The other bryo-communities have been framed into the classes Cladonio digitatae-Lepidozietea reptantis, Ceratodonto purpurei-Polytrichetea piliferii and Psoretea decipientis again

    A FIRST-ORDER LOGIC CHARACTERIZATION OF SAFETY AND CO-SAFETY LANGUAGES

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    Linear Temporal Logic (LTL) is one of the most popular temporal logics and comes into play in a variety of branches of computer science. Among the various reasons of its widespread use there are its strong foundational properties: LTL is equivalent to counter-free ω-automata, to star-free ω-regular expressions, and (by Kamp’s theorem) to the First-Order Theory of Linear Orders (FO-TLO). Safety and co-safety languages, where a finite prefix suffices to establish whether a word does not belong or belongs to the language, respectively, play a crucial role in lowering the complexity of problems like model checking and reactive synthesis for LTL. Safety-LTL (resp., coSafety-LTL) is a fragment of LTL where only the tomorrow, the weak tomorrow and the until temporal modalities (resp., the tomorrow, the weak tomorrow and the release temporal modalities) are allowed, that recognises safety (resp., co-safety) languages only. The main contribution of this paper is the introduction of a fragment of FO-TLO, called Safety-FO, and of its dual coSafety-FO, which are expressively complete with respect to the LTL-definable safety and co-safety languages. We prove that they exactly characterize Safety-LTL and coSafety-LTL, respectively, a result that joins Kamp’s theorem, and provides a clearer view of the characterization of (fragments of) LTL in terms of first-order languages. In addition, it gives a direct, compact, and self-contained proof that any safety language definable in LTL is definable in Safety-LTL as well. As a by-product, we obtain some interesting results on the expressive power of the weak tomorrow operator of Safety-LTL, interpreted over finite and infinite words. Moreover, we prove that, when interpreted over finite words, Safety-LTL (resp. coSafety-LTL) devoid of the tomorrow (resp., weak tomorrow) operator captures the safety (resp., co-safety) fragment of LTL over finite words. We then investigate some formal properties of Safety-FO and coSafety-FO: (i) we study their succinctness with respect to their modal counterparts, namely, Safety-LTL and coSafety-LTL; (ii) we illustrate an important practical application of them in the context of reactive synthesis; (iii) we compare them with expressively equivalent first-order fragments. Last but not least, we provide different characterizations of the (co-)safety fragment of LTL in terms of temporal logics, automata, and regular expressions

    Fairness, assumptions, and guarantees for extended bounded response LTL+P synthesis

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    Realizability and reactive synthesis from temporal logics are fundamental problems in formal verification. The complexity of these problems for linear temporal logic with past (LTL+P) led to the identification of fragments with lower complexities and simpler algorithms. Recently, the logic of extended bounded response LTL+P (LTLEBR+ P for short) has been introduced. It allows one to express safety languages definable in LTL+P and it is provided with an efficient, fully symbolic algorithm for reactive synthesis. This paper features four related contributions. First, we introduce GR-EBR , an extension of LTLEBR+ P with fairness conditions, assumptions, and guarantees that, on the one hand, allows one to express properties beyond the safety fragment and, on the other, it retains the efficiency of LTLEBR+ P in practice. Second, we the expressiveness of GR-EBR starting from the expressiveness of its fragments. In particular, we prove that: (1) LTLEBR+ P is expressively complete with respect to the safety fragment of LTL+P , (2) the removal of past operators from LTLEBR+ P results into a loss of expressive power, and (3) GR-EBR is expressively equivalent to the logic GR(1) of Bloem et al. Third, we provide a fully symbolic algorithm for the realizability problem from GR-EBR specifications, that reduces it to a number of safety subproblems. Fourth, to ensure soundness and completeness of the algorithm, we propose and exploit a general framework for safety reductions in the context of realizability of (fragments of) LTL+P . The experimental evaluation shows promising results
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