453 research outputs found

    A logical study of local and global graded similarities

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    In this work we study the relationship between global and local similarities in the graded framework of fuzzy class theory (FCT), in which there already exists a graded notion of similarity. In FCT we can express the fact that a fuzzy relation is reflexive, symmetric, or transitive up to a certain degree, and similarity is defined as a first-order sentence, which is the fusion of three sentences corresponding to the graded notions of reflexivity, symmetry, and transitivity. This allows us to speak in a natural way of the degree of similarity of a relation. We consider global similarities defined from local similarities using t-norms as aggregation operators, and we obtain some results in the framework of FCT that, adequately interpreted, allow us to say that when we take a t-norm as an aggregation operator, the properties of reflexivity, symmetry, and transitivity of fuzzy binary relations are inherited from the local to the global level, and that the global similarity is a congruence if some of the local similarities are congruence

    Social Preferences, Skill Segregation and Wage Dynamics

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    We study the earning structure and the equilibrium asignment of workers to firms in a model in which workers have social preferences, and skills are perfectly substitutable in production. Firms offer long-term contracts, and we allow for frictions in the labour market in the form of mobility costs. The model delivers specific predictions about the nature of worker flows, about the characteristic of workplace skill segregation, and about wage dispersion both within and cross firms. We shows that long-term contracts in the resence of social preferences associate within-firm wage dispersion with novel "internal labour market" features such as gradual promotions, productivity-unrelated wage increases, and downward wage flexibility. These three dynamic features lead to productivity-unrelated wage volatily within firms.Publicad

    X-chromosome tiling path array detection of copy number variants in patients with chromosome X-linked mental retardation

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    Contiene 3 ficheros adicionales con información suplementaria.-- et al.[Background] Aproximately 5–10% of cases of mental retardation in males are due to copy number variations (CNV) on the X chromosome. Novel technologies, such as array comparative genomic hybridization (aCGH), may help to uncover cryptic rearrangements in X-linked mental retardation (XLMR) patients. We have constructed an X-chromosome tiling path array using bacterial artificial chromosomes (BACs) and validated it using samples with cytogenetically defined copy number changes. We have studied 54 patients with idiopathic mental retardation and 20 controls subjects.[Results] Known genomic aberrations were reliably detected on the array and eight novel submicroscopic imbalances, likely causative for the mental retardation (MR) phenotype, were detected. Putatively pathogenic rearrangements included three deletions and five duplications (ranging between 82 kb to one Mb), all but two affecting genes previously known to be responsible for XLMR. Additionally, we describe different CNV regions with significant different frequencies in XLMR and control subjects (44% vs. 20%).[Conclusion] This tiling path array of the human X chromosome has proven successful for the detection and characterization of known rearrangements and novel CNVs in XLMR patients.The authors thank the "Genoma España" and Genome Canada joint R+D+I projects in human health, plants and aquiculture; the former "Departament d'Universitats i Societat de la Informació" (DURSI) and the "Departament de Salut", from the Catalan Autonomous Government (2005SGR00008 - Generalitat de Catalunya); the Instituto de Salud Carlos III (PI041126, CIBER-ESP), the EU's Sixth Framework Programme [FP6-2005-LIFESCIHEALTH-7; ANEUPLOIDY No. 037627] and Fundación Areces (U-2006-FARECES-O).Peer reviewe

    Limited Lifespan of Fragile Regions in Mammalian Evolution

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    An important question in genome evolution is whether there exist fragile regions (rearrangement hotspots) where chromosomal rearrangements are happening over and over again. Although nearly all recent studies supported the existence of fragile regions in mammalian genomes, the most comprehensive phylogenomic study of mammals (Ma et al. (2006) Genome Research 16, 1557-1565) raised some doubts about their existence. We demonstrate that fragile regions are subject to a "birth and death" process, implying that fragility has limited evolutionary lifespan. This finding implies that fragile regions migrate to different locations in different mammals, explaining why there exist only a few chromosomal breakpoints shared between different lineages. The birth and death of fragile regions phenomenon reinforces the hypothesis that rearrangements are promoted by matching segmental duplications and suggests putative locations of the currently active fragile regions in the human genome

    Diaporthe diversity and pathogenicity revealed from a broad survey of grapevine diseases in Europe

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    [EN] Species of Diaporthe are considered important plant pathogens, saprobes, and endophytes on a wide range of plant hosts. Several species are well-known on grapevines, either as agents of pre-or post-harvest infections, including Phomopsis cane and leaf spot, cane bleaching, swelling arm and trunk cankers. In this study we explore the occurrence, diversity and pathogenicity of Diaporthe spp. associated with Vitis vinifera in major grape production areas of Europe and Israel, focusing on nurseries and vineyards. Surveys were conducted in Croatia, Czech Republic, France, Hungary, Israel, Italy, Spain and the UK. A total of 175 Diaporthe strains were isolated from asymptomatic and symptomatic shoots, branches and trunks. A multi-locus phylogeny was established based on five genomic loci (ITS, tef1, cal, his3 and tub2), and the morphological characters of the isolates were determined. Preliminary pathogenicity tests were performed on green grapevine shoots with representative isolates. The most commonly isolated species were D. eres and D. ampelina. Four new Diaporthe species described here as D. bohemiae, D. celeris, D. hispaniae and D. hungariae were found associated with affected vines. Pathogenicity tests revealed D. baccae, D. celeris, D. hispaniae and D. hungariae as pathogens of grapevines. No symptoms were caused by D. bohemiae. This study represents the first report of D. ambigua and D. baccae on grapevines in Europe. The present study improves our understanding of the species associated with several disease symptoms on V. vinifera plants, and provides useful information for effective disease management.This research was supported by the European COST Action FA1303 on Sustainable control of grapevine trunk diseases (ManaGTD). Surveys and fungal collection performed in Hungary were supported by Szechenyi 2020 programme, the European Regional Development Fund, the Hungarian Government (GINOP-2.3.2-15-2016-00061) and EU H2020 project no. 652601.Guarmaccia, V.; Groenewald, JZ.; Woodhall, J.; Armengol Fortí, J.; Cinelli, T.; Eichmeier, A.; Ezra, D.... (2018). Diaporthe diversity and pathogenicity revealed from a broad survey of grapevine diseases in Europe. Persoonia - Molecular Phylogeny and Evolution of Fungi. 40:135-153. https://doi.org/10.3767/persoonia.2018.40.06S1351534

    The Network Composition of Aggregate Unemployment

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    We develop a theory of unemployment in which workers search for jobs through a network of firms, the labor flow network (LFN). The lack of an edge between two companies indicates the impossibility of labor flows between them due to high frictions. In equilibrium, firms' hiring behavior correlates through the network, modulating labor flows and generating aggregate unemployment. This theory provides new micro-foundations for the aggregate matching function, the Beveridge curve, wage dispersion, and the employer-size premium. Using employer-employee matched records, we study the effect of the LFN topology through a new concept: `firm-specific unemployment'

    Management of grapevine trunk diseases: knowledge transfer, current strategies and innovative strategies adopted in Europe

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    [EN] Since the early 1990s, grapevine trunk diseases (GTDs) have posed threats for viticulture. Esca complex, Eutypa- and Botryosphaeria-diebacks, mostly detected in adult vineyards, are currently responsible for considerable economic losses in the main vine-growing areas of the world. Other GTDs, such as Petri- (Esca complex) and Black-foot diseases, are emerging problems in grapevine nurseries (resulting in grafting failures and/or loss of saleable plants) and in young vineyards. The impacts of GTDs in modern viticulture depend on several factors, some related to their complexity, and others linked to host plant characteristics, changes in vineyard management and to the scarcity of simple tools for their control. For these reasons control of GTDs remains difficult, also depending on knowledge transfer from research to field and vice versa. This paper outlines the main preventive and curative techniques currently applied, scientifically tested or not that have resulted from the outcomes of "Winetwork", a European Union funded project with special emphasis on the promising and innovative approaches.Mondello, V.; Larignon, P.; Armengol Fortí, J.; Kortekamp, A.; Váczy, K.; Prezman, F.; Serrano, E.... (2018). Management of grapevine trunk diseases: knowledge transfer, current strategies and innovative strategies adopted in Europe. PHYTOPATHOLOGIA MEDITERRANEA. 57(3):369-383. https://doi.org/10.14601/Phytopathol_Mediterr-23942S36938357

    The Absence of Caspase-8 in the Dopaminergic System Leads to Mild Autism-like Behavior

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    In the last decade, new non-apoptotic roles have been ascribed to apoptotic caspases. This family of proteins plays an important role in the sculpting of the brain in the early stages of development by eliminating excessive and nonfunctional synapses and extra cells. Consequently, impairments in this process can underlie many neurological and mental illnesses. This view is particularly relevant to dopamine because it plays a pleiotropic role in motor control, motivation, and reward processing. In this study, we analyze the effects of the elimination of caspase-8 (CASP8) on the development of catecholaminergic neurons using neurochemical, ultrastructural, and behavioral tests. To do this, we selectively delete the CASP8 gene in cells that express tyrosine hydroxylase with the help of recombination through the Cre-loxP system. Our results show that the number of dopaminergic neurons increases in the substantia nigra. In the striatum, the basal extracellular level of dopamine and potassium-evoked dopamine release decreased significantly in mice lacking CASP8, clearly showing the low dopamine functioning in tissues innervated by this neurotransmitter. This view is supported by electron microscopy analysis of striatal synapses. Interestingly, behavioral analysis demonstrates that mice lacking CASP8 show changes reminiscent of autism spectrum disorders (ASD). Our research reactivates the possible role of dopamine transmission in the pathogenesis of ASD and provides a mild model of autism.Ministerio de Economía y Competitividad RTI2018-098645-B-I00, PID2019-109569GB-I00, RTI2018-099778-B-I00Junta de Andalucía P18-RT-1372, US-1264806, PI-0080-2017, PI-0009-2017, PI-0134-2018, PEMP-0008-2020, P20_00958, CTS-510Instituto de Salud Carlos III PI18/01691Instituto de Investigación e Innovación en Ciencias Biomédicas de Cádiz-INiBICA LI19/06IN-CO22, IN-C09European Union 95568

    Epiphytic metazoans on emergent macrophytes in oxbow lakes of the Krapina River, Croatia: differences related to plant species and limnological conditions

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    This study investigated the structure of the epiphytic metazoans on emerged macrophytes in the littoral zone of two oxbow lakes with different trophic levels. Differences in the diversity and density of the epiphytic metazoans were analyzed in relation to plant architecture (simple or complex stems), food resources (algae and detritus) and water characteristics (transparency and derived trophic state index). Asignificant negative correlation was found between detritus on plants as food resource, and diversity and density of epiphytic metazoans, indicating grazing of microphagous species. Rotifers dominated in diversity and density in the epiphyton on all habitats. Total density of metazoans, rotifers and copepods in epiphyton were significantly higher on Mentha in mesotrophic lake than on Iris in a eutrophic lake.We presume that macrophyte belt width and trophic state governed biotic interactions and consequently epiphytic assemblages more strongly than macrophyte architecture. However, a Mentha habitat showed a slightly higher density and diversity of epiphytic metazoans in relation to Iris at the same site, but these differences were not significant
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