912 research outputs found

    Aging dynamics of +-J Edwards-Anderson spin glasses

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    We analyze by means of extensive computer simulations the out of equilibrium dynamics of Edwards-Anderson spin glasses in d=4 and d=6 dimensions with +-J interactions. In particular, we focus our analysis on the scaling properties of the two-time autocorrelation function in a range of temperatures from T=0.07 T_c to T=0.75 T_c in both systems. We observe that the aging dynamics of the +-J models is different from that observed in the corresponding Gaussian models. In both the 4d and 6d models at very low temperatures we study the effects of discretization of energy levels. Strong interrupted aging behaviors are found. We argue that this is because in the times accessible to our simulations the systems are only able to probe activated dynamics through the lowest discrete energy levels and remain trapped around nearly flat regions of the energy landscape. For temperatures T >= 0.5 T_c in 4d we find logarithmic scalings that are compatible with dynamical ultrametricity, while in 6d the relaxation can also be described by super-aging scalings.Comment: 7 pages, 10 figure

    Pragmatic language disorder in Parkinson's disease and the potential effect of cognitive reserve

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    It is known that patients with Parkinson\u2019s Disease (PD) may show deficits in several areas of cognition, including speech and language abilities. One domain of particular interest is pragmatics, which refers to the capacity of using language in context for a successful communication. Several studies showed that some specific aspects of pragmatics \u2013 both in production and in comprehension \u2013 might be impaired in patients with PD. However, a clear picture of pragmatic abilities in PD is still missing, as most of the existing studies focused on specific aspects of the pragmatic competence rather than on sketching a complete pragmatic profile. Moreover, little is known on the potential role of protective factors in compensating the decline of communicative skills as the disease progresses. The present study has two aims: (1) to provide a complete picture of pragmatic abilities in patients with PD, by using a comprehensive battery (Assessment of Pragmatic Abilities and Cognitive Substrates, APACS) and by investigating the relationship with other aspects of cognitive functioning (e.g., working memory and Theory of Mind) and (2) to investigate whether Cognitive Reserve, i.e., the resilience to cognitive impairment provided by life experiences and activities, may compensate for the progressive pragmatic deficits in PD. We found that patients with PD, compared to healthy matched controls, had worse performance in discourse production and in the description of scenes, and that these impairments were tightly correlated with the severity of motor impairment, suggesting reduced intentionality of engaging in a communicative exchange. Patients with PD showed also an impairment in comprehending texts and humor, suggesting a problem in inferring from stories, which was related to general cognitive impairment. Notably, we did not find any significant difference between patients and controls in figurative language comprehension, a domain that is commonly impaired in other neurodegenerative diseases. This might be indicative of a specific profile of pragmatic impairment in patients with PD, worth of further investigation. Finally, Cognitive Reserve measures showed a high degree of association with pragmatic comprehension abilities, suggesting that the modification of life-styles could be a good candidate for compensating the possible problems in understanding the pragmatic aspects of language experienced by patients with PD

    Homologous self-organising scale-invariant properties characterise long range species spread and cancer invasion

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    The invariance of some system properties over a range of temporal and/or spatial scales is an attribute of many processes in nature1, often characterised by power law functions and fractal geometry2. In particular, there is growing consensus in that fat-tailed functions like the power law adequately describe long-distance dispersal (LDD) spread of organisms 3,4. Here we show that the spatial spread of individuals governed by a power law dispersal function is represented by a clear and unique signature, characterised by two properties: A fractal geometry of the boundaries of patches generated by dispersal with a fractal dimension D displaying universal features, and a disrupted patch size distribution characterised by two different power laws. Analysing patterns obtained by simulations and real patterns from species dispersal and cell spread in cancer invasion we show that both pattern properties are a direct result of LDD and localised dispersal and recruitment, reflecting population self-organisation

    Dynamics and nonequilibrium states in the Hamiltonian mean-field model: A closer look

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    We critically revisit the evidence for the existence of quasistationary states in the globally coupled XY (or Hamiltonian mean-field) model. A slow-relaxation regime at long times is clearly revealed by numerical realizations of the model, but no traces of quasistationarity are found during the earlier stages of the evolution. We point out the nonergodic properties of this system in the short-time range, which makes a standard statistical description unsuitable. New aspects of the evolution during the nonergodic regime, and of the energy distribution function in the final approach to equilibrium, are disclosed

    Vinorelbine-based salvage therapy in HER2-positive metastatic breast cancer patients progressing during trastuzumab-containing regimens: a retrospective study

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    <p>Abstract</p> <p>Background</p> <p>The vinka-alkaloyd vinorelbine is a potentially valuable treatment in patients with HER2-positive, trastuzumab-resistant advanced breast cancer. We sought to document the clinical activity of vinorelbine-based salvage treatments in this clinical setting.</p> <p>Methods</p> <p>We analyzed a cohort of 424 consecutive women receiving trastuzumab-based therapy for HER2-positive advanced breast cancer. Of these, 299 were identified as progressing during the initial trastuzumab-based treatment, and 77 received vinorelbine-based therapy as first salvage treatment. Central review of pathological specimens revealed that 70 patients had HER2-amplification detected by FISH. For these patients we determined overall response rate (ORR = complete-CR + partial-PR) and clinical benefit (CB = CR+PR+ Stable disease lasting at least 6 months), time to progression (TTP) and overall survival (OS) from the initiation of vinorelbine-based salvage therapy.</p> <p>Results</p> <p>In 60 patients who were evaluable for tumor response, ORR and CB rates were 28% (95% C.I. 18%-41%) and 50% (95% C.I. 38%-62%), respectively. Median follow-up from the initiation of salvage therapy was 15 months (range 1–63 months). Median TTP and OS were 7.1 months (95% C.I. 6.6–7.7 months) and 21 months (95% C.I. 14.3–27.7 months), respectively. No differences in clinical outcomes were observed according to whether vinorelbine was administered as a single agent or in combination with other cytostatics, or whether trastuzumab was stopped or continued beyond disease progression.</p> <p>Conclusion</p> <p>our findings suggests that vinorelbine-based combinations are active and should be further evaluated in studies conducted in trastuzumab-resistant patients, including those evaluating newer HER2-targeting agents.</p

    Lecciana, a new low-vigour olive cultivar suitable for super high density orchards and for nutraceutical evoo production

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    Cultivar is the key factor for sustainability of the olive super high density planting system (SHD). ‘Lecciana’ is a new olive cultivar for oil production obtained in 1998 by a controlled cross between cv. Arbosana (♀) and cv. Leccino (♂) in a breeding program as part of an international research agreement between Agromillora Iberia S.L.U. and University of Bari. ‘Lecciana’ is the first olive cultivar of Italian descent suitable for SHD, featuring all the vegetative and productive traits required for efficient, sustainable olive growing intensification. Thanks to low vigor, early bearing (3rd year after planting), high yield efficiency (about 0.5 kg of fruits cm−2 of trunk section area) and good fruit size (3.5 g), ‘Lecciana’ could be planted with tree densities over 1,200 trees per hectare for an efficient continuous mechanical harvesting. High frost resistance, very low pistil abortion (3%), high fruit set (3%), oil content (over 19% fw) and, above all, good unsaturated fatty acids profile, polyphenols content (over 450 mg kg−1 ) and fruitiness median are the main distinctive characters of this new cultivar. The oils of ‘Lecciana’ fall into the category ‘nutraceutical EVOOs’ which can benefit from the specific functional health claim

    Tagging Scientific Publications using Wikipedia and Natural Language Processing Tools. Comparison on the ArXiv Dataset

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    In this work, we compare two simple methods of tagging scientific publications with labels reflecting their content. As a first source of labels Wikipedia is employed, second label set is constructed from the noun phrases occurring in the analyzed corpus. We examine the statistical properties and the effectiveness of both approaches on the dataset consisting of abstracts from 0.7 million of scientific documents deposited in the ArXiv preprint collection. We believe that obtained tags can be later on applied as useful document features in various machine learning tasks (document similarity, clustering, topic modelling, etc.)

    Ampelographic and Molecular Characterisation of Aglianico Accessions (Vitis vinifera L.) Collected in Southern Italy

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    To characterise 31 different Aglianico accessions randomly collected in Southern Italy, 30 ampelographicdescriptors, 13 SSRs and 10 AFLP primer combinations were analysed. An appreciable variation ofampelographic descriptors was revealed mainly by mature leaf traits, while very few variations wererecorded for shoot and berry traits. Similarly, all SSR loci revealed molecular monomorphism and AFLPswith a very high genetic similarity (Dice coefficient) among all the accessions considered. One of the aimsof this study was to clarify the genetic assessment of Aglianico Nero and Aglianico del Vulture Nero,since they are registered as two different cultivars with distinct varietal codes at the Italian Register ofGrape Varieties. Registered Aglianico Nero and Aglianico del Vulture Nero were included in the analyses,compared and used as reference material. Our plants showed that all the accessions tested, independentfrom the biotype, and the two registered cultivars belong to the same genotype, suggesting that, as reportedby the Vitis International Variety Catalogue, a case of synonymy occurred between Aglianico Nero andAglianico del Vulture Nero. These cultivars could therefore be considered as a single cultivar. Moreover,the AFLP data revealed a partial match between morphological and molecular data, showing that theAFLP molecular method was able to discriminate between different accessions belonging to the samecultivar
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