940 research outputs found

    Passive ocean acoustic tomography: theory and experiment

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    In this paper the Passive Ocean Acoustic Tomography (P-OAT) methodology is presented. This technique, avoiding the use of a dedicated active sound source, estimates the sea water temperature spatial distribution from the received noise emitted from ships of opportunity. The feasibility of the proposed methodology has been confirmed both by test-runs on semi-synthetic data and by the use of real acoustic and environmental data collected during INTIMATE00 experiment performed on October 2000 in the Atlantic Ocean off the Portuguese coasts

    On well-posedness, stability, and bifurcation for the axisymmetric surface diffusion flow

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    In this article, we study the axisymmetric surface diffusion flow (ASD), a fourth-order geometric evolution law. In particular, we prove that ASD generates a real analytic semiflow in the space of (2 + \alpha)-little-H\"older regular surfaces of revolution embedded in R^3 and satisfying periodic boundary conditions. We also give conditions for global existence of solutions and prove that solutions are real analytic in time and space. Further, we investigate the geometric properties of solutions to ASD. Utilizing a connection to axisymmetric surfaces with constant mean curvature, we characterize the equilibria of ASD. Then, focusing on the family of cylinders, we establish results regarding stability, instability and bifurcation behavior, with the radius acting as a bifurcation parameter for the problem.Comment: 37 pages, 6 figures, To Appear in SIAM J. Math. Ana

    Non-destructive characterisation of a Villanovan sword using time-of-flight neutron diffraction

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    In the present work we report an example application of time-of-flight neutron diffraction for the non-destructive characterisation of ancient bronzes. A Villanovan sword tightly joined to its scabbard by corrosion has been investigated. Data on alloy composition of the different parts and information about the manufacturing techniques have been successfully achieved. The present study is part of an extensive non-destructive investigation program concerning bronze productions of Central Italy during the Iron Age

    Linguistic diversity, multilingualism, and cognitive skills: A study of disadvantaged children in India

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    Multilingualism and linguistic diversity are the norm in India. Although studies have shown a relation between bilingualism and cognitive gains, linguistic diversity has so far been ignored as a potential factor affecting cognitive skills. This study aims to fill this gap by examining how cognitive skillsā€”as measured by the n-back and Ravenā€™s Colored Progressive Matrices tasksā€”are affected by multilingualism and/or sociolinguistic diversity in a large cohort of socioeconomically disadvantaged primary school children in two urban sites of India: Delhi and Hyderabad. We present a questionnaire estimating sociolinguistic diversity and show that this measure assesses a distinct construct, as compared to a childā€™s multilingualism. Children were classified as growing up monolingually or bilingually, depending on whether they grew up with one or more languages in the home. Regarding cognitive performance, bilinguals were found to outperform monolinguals on the n-back task, as well as on the Ravenā€™s task. In addition, a socially and linguistically diverse environment seems to enhance cognitive performance for children who are not multilingual themselves. Finally, several contextual factors such as city were found to influence cognitive performance. Overall, this shows that cognitive tasks are subject to contextual effects and that bilingualism and linguistic diversity can enhance cognitive performance of children in disadvantaged contexts.</jats:p

    Therapeutic Frameworks in Integration Sessions in Substance-Assisted Psychotherapy: A Systematized Review

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    Serotonergic psychedelics and related substances have been explored as potential adjuncts in substance-assisted psychotherapy (SAPT) for treating various disorders. SAPT can be divided into three phases: preparation, administration, and integration. Integration is commonly defined as the comprehension and effective application of insights from psychedelic experiences into everyday life. However, there is limited research regarding the most appropriate therapeutic approach during integration sessions in SAPT. In this article, we discuss the current evidence for different therapeutic frameworks for integrations sessions when serotonergic psychedelics and entactogens are used as adjuncts to psychotherapy. We conducted a systematized review of the literature following PRISMA guidelines and searched PsycINFO, MEDLINE, and Cochrane Library databases. The final synthesis included 75 clinical trials, mixed-methods investigations, treatment manuals, study protocols, quasi-experiments, qualitative investigations, descriptive studies, opinion papers, reviews, books and book chapters, published until November 11, 2022. The effects that various therapeutic approaches for integration sessions have on therapeutic outcome have not been investigated by means of rigorous research. Most of the available evidence we retrieved was not supported by empirical data, thus limiting any conclusive statements regarding appropriate therapeutic frameworks for integration sessions for SAPT. Current clinical studies have used a range of therapeutic frameworks with the majority drawing from the humanistic-experiential tradition. While integration is regarded as crucial for the safe application of SAPTHowever, there is currently an insufficient evidence base to suggest that any type of therapy is most effective for guiding integration sessions. Systematic investigation of different therapeutic frameworks for integration and additional therapy-related factors is needed
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