792 research outputs found

    Lower genetic diversity in the limpet Patella caerulea on urban coastal structures compared to natural rocky habitats

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    Human-made structures are increasingly found in marine coastal habitats. The aim of the present study was to explore whether urban coastal structures can affect the genetic variation of hard-bottom species. We conducted a population genetic analysis on the limpet Patella caerulea sampled in both natural and artificial habitats along the Adriatic coast. Five microsatellite loci were used to test for differences in genetic diversity and structure among samples. Three microsatellite loci showed strong Hardy-Weinberg disequilibrium likely linked with the presence of null alleles. Genetic diversity was significantly higher in natural habitat than in artificial habitat. A weak but significant differentiation over all limpet samples was observed, but not related to the type of habitat. While the exact causes of the differences in genetic diversity deserve further investigation, these results clearly point that the expansion of urban structures can lead to genetic diversity loss at regional scales

    Comovements and Correlations in International Stock Markets

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    The interrelationship between international stock markets is a key issue in international portfolio management and risk measurement. The dynamics of security returns and their risk characteristics have a crucial role in the financial market theory. Recent empirical studies have tested market efficiency measuring the degree of integration of international financial markets. These studies have shown that international markets react quickly to news but they are volatile and difficult to predict, with a changing correlation structure of security returns among countries. In this paper the nature of the relationship between the major international stock markets in Canada, Japan, UK and the US, is analysed using the common trends and common cycles approach. The presence of co-movements is investigated to try to detect a long-term stationary component, the common trend, and a short-term stationary cyclical component, among international stock markets. The implications for international portfolio management are also discussed

    Identifying conformational changes with site-directed spin labeling reveals that the GTPase domain of HydF is a molecular switch

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    [FeFe]-hydrogenases catalyse the reduction of protons to hydrogen at a complex 2Fe[4Fe4S] center called H-cluster. The assembly of this active site is a multistep process involving three proteins, HydE, HydF and HydG. According to the current models, HydF has the key double role of scaffold, upon which the final H-cluster precursor is assembled, and carrier to transfer it to the target hydrogenase. The X-ray structure of HydF indicates that the protein is a homodimer with both monomers carrying two functional domains: a C-terminal FeS cluster-binding domain, where the precursor is assembled, and a N-terminal GTPase domain, whose exact contribution to cluster biogenesis and hydrogenase activation is still elusive. We previously obtained several hints suggesting that the binding of GTP to HydF could be involved in the interactions of this scaffold protein with the other maturases and with the hydrogenase itself. In this work, by means of site directed spin labeling coupled to EPR/PELDOR spectroscopy, we explored the conformational changes induced in a recombinant HydF protein by GTP binding, and provide the first clue that the HydF GTPase domain could be involved in the H-cluster assembly working as a molecular switch similarly to other known small GTPases

    Lexical, Morphological, and Syntactic Characteristics of Verbs in the Spontaneous Production of Italian Children

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    This study investigates from a developmental point of view the lexical, morphological, and syntactic characteristics of verb production during the first stages of language acquisition. The spontaneous productions of children with different mean length of utterance (MLU) were analysed, examining the relative production of different types of verbs (transitive, intransitive, and mixed), the arguments expressed or omitted in the utterances containing a verb, the morphological inflections produced by the children for each verb, and the generalisation of the syntactic construction with which specific verbs were produced. Data are interpreted in support of the hypothesis that children have a limited abstract knowledge of verbs in the early period of multiword utterance production and that the process of abstractness and generalisation develops gradually on the basis of linguistic experience

    A Cloud-Native Web Application for Assisted Metadata Generation and Retrieval: THESPIAN-NER

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    Within the context of the Competence Centre for the Conservation of Cultural Heritage (4CH) project, the design and deployment of a platform-as-a-service cloud infrastructure for the first European competence centre of cultural heritage (CH) has begun, and some web services have been integrated into the platform. The first integrated service is the INFN-CHNet web application for FAIR storage of scientific analysis on CH: THESPIAN-Mask. It is based on CIDOC-CRM-compatible ontology and CRMhs, describing the scientific metadata. To ease the process of metadata generation and data injection, another web service has been developed: THESPIAN-NER. It is a tool based on a deep neural network for named entity recognition (NER), enabling users to upload their Italian-written report files and obtain labelled entities. Those entities are used as keywords either to serve as (semi)automatically custom queries for the database, or to fill (part of) the metadata form as a descriptor for the file to be uploaded. The services have been made freely available in the 4CH PaaS cloud platform

    Positive and negative effects of collaboration on suggestibility and false memory in online groups

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    Previous studies demonstrated the positive and negative efects of collaboration on memory (both veridical and false recall) and suggestibility in face-to-face contexts. However, it remains unclear whether the same results can be observed in a virtual context. To clarify this issue, the present study examined the performance of 10 nominal triads and 10 collaborative triads in a fully online setting. Participants interacted live, in videoconference and were tested with the Gudjonsson Suggestibility Scale (GSS) and the Deese/Roediger-McDermott (DRM) task. For the GSS, the results replicated the in-person pattern of results, with collaborative triads showing the standard inhibition efect in the immediate and delayed (after 24 h) recall tasks; in addition, collaborative triads were less suggestible than nominal triads. For the DRM, we likewise found that collaboration decreased the recall and recognition of both studied items (the standard inhibitory effect) and critical lures (the error-pruning effect). We therefore conclude that remembering in a virtual context exhibits the same general properties as its in-person counterpart, at least when using a videoconference setting
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