Archivio Istituzionale della Ricerca- Università del Salento
Not a member yet
80217 research outputs found
Sort by
Mutual estimates of time-frequency representations and uncertainty principles
Get PDFIn this paper we give different estimates between Lebesgue norms of quadratic time-frequency representations. We show that, in some cases, it is not possible to have such bounds in classical Lp spaces, but the Lebesgue norm needs to be suitably weighted. This leads to consider weights of polynomial type, and, more generally, of ultradifferentiable type, and this, in turn, gives rise to use as functional setting the ultradifferentiable classes. As applications of such estimates we deduce uncertainty principles both of Donoho-Stark type and of local type for representations
Multisport-Integrated Training for Rugby Instructors: Success and Effects on Minirugby Players
No full textAbstract: Background/Objectives: The educational system thinking approach (ST) takes a holistic vision of instructors/teachers and learners’ relationships, making sports pivotal for reflection on education. This study evaluated the efficacy of a multisport ST-based course on minirugby instructors’ teaching competence and children players’ motor conduct. Methods: The twenty-five rugby instructors (IAC) attended the 25 h course and the children of their teams (n = 109, Ch-IAC) participated in this study as experimental groups. Twenty-five rugby instructors who were not attending the course (I-CON) and their pupils (n = 111, Ch-CON) acted as control groups. Changes in instructors’ teaching competence (by the Instrument for Identifying the Teaching Style and the System for Observing Fitness Instruction Time) and children’s motor conduct (by the Körperkoordinationtest für Kinder test, the Game Performance Assessment Instrument, the Physical Activity Enjoyment Scale, and the physical self-efficacy scale for children) were assessed. Results: Thanks to the
education received, IAC improved in didactics and methodological competence. They learned to use more production teaching styles than CON (10.5 ± 9.3% vs. 0% of the lesson time, p < 0.05), reduce children’s inactive lesson time for management (−5.1 ± 3.3% vs. 1.1 ± 3.1%, p < 0.05) and promote more outside lesson topics (4.4 ± 3.2% vs. 0%, p < 0.05). In addition, compared to Ch-CON, Ch-IAC significantly improved motor coordination, game performance, enjoyment, and self-efficacy (p < 0.05). Conclusions: Children’s enjoyment and self-efficacy acted as mediators that amplified the effects of the multisport training course. At the same time, the instructor’s didactical and methodological competence were
moderators directly favoring or worsening children’s motor competence. Such an inte grated multisport model is applicable and suggested for improving sports performance and education processes
Underwater endoscopic submucosal dissection for large non-pedunculated colorectal polyps
No full textPost-Cardiotomy Extracorporeal Membrane Oxygenation After Elective, Urgent, and Emergency Cardiac Operations: insights from the PELS observational study
No full textMarine algal metabolites as cellular antioxidants: a study of caulerpin and caulerpinic acid in Saccharomyces cerevisiae
No full textOxidative stress caused by excessive reactive oxygen species (ROS) contributes to numerous chronic diseases. Marine green algae of the Caulerpa genus are rich in bioactive compounds with potential antioxidant activity. Objective: This study aimed to evaluate the intracellular antioxidant effects of caulerpin (CAU) and its derivative caulerpinic acid (CA) using Saccharomyces cerevisiae as a eukaryotic model. Methods: Yeast cells were pretreated with 1 μM of CAU or CA, or with 1 μM of resveratrol (RESV) as a positive control, then exposed to 2 mM of H2O2. Growth, ROS levels, oxidative damage markers, and antioxidant defenses were assessed. Results: Both CAU and CA significantly improved cell survival under oxidative stress, restoring growth rates (CAU: 0.129 h−1, CA: 0.137 h−1) and doubling times (CAU: 5.38 h, CA: 5.07 h) close to control values. Intracellular ROS accumulation, protein carbonylation, and lipid peroxidation were reduced to near-baseline levels. While catalase (Cat) and superoxide dismutase (Sod) activity remained unchanged, CAU and CA elevated intracellular glutathione (GSH) levels (1.6–1.8 fold) and preserved glutathione peroxidase (GPx) activity, compared to stressed cells without antioxidant pretreatment. Conclusions: CAU and CA act as effective intracellular antioxidants, primarily via ROS scavenging and GSH-dependent pathways. These findings support their potential as natural candidates for developing antioxidant-based therapies against ROS-related disorders
Complex Covariance Models
No full textThe aim of this work is to introduce the theoretical background regarding the complex formalism of a spatial and spatio-temporal random field and to present some families of complex-valued covariance models. In geostatistical literature, the study of the evolution of vector data with two components in space and space-time is often developed in the framework of the theory of complex-valued random fields. However, some efforts are required in the multivariate context. The computational details of their fitting are discussed through an environmental case study
The influence of plasticity on cavity expansion in lithium-ion battery electrodes
Get PDFWe examine the expansion of a small cavity within a spherical electrode of lithium-ion batteries (LIBs) during the galvanostatic charging process. Nonlinear theories are applied to account for the large deformations typical of silicon-based electrodes. Our analysis focuses on how plasticity influences the evolution of the cavity's radius by associating an elastic potential with the particle and considering a chemical potential that may depend on stress or be independent of it. We find that when plasticity is taken into account, the behaviour of a small hole undergoes complex changes. The mathematical problem at hand involves coupled nonlinear partial differential equations, which we solve numerically. We assume elastic incompressibility, enabling a simple numerical scheme that can be implemented in any programming language without relying on commercial finite element software typically used in this context
Safety Maturity Models for supporting Near Miss Management Systems in Industrial Sector
No full textMaturity models are becoming increasingly popular nowadays as an assessment and improvement tool in several industrial fields. These models are often developed and adopted for supporting process improvement by identifying their current maturity level and in identifying the most critical process to focus on for improving performance of the specific strategy/process. Some examples have been also defined in the safety field by focusing on evaluating safety culture of an enterprise and/or an organization. The scientific literature presents several Safety Culture Maturity Models (SCMMs) developed over the years, although many of them still have gaps in terms of tools for quantitatively measuring the level of maturity of an organization’s safety culture. One of the several elements and indicators considered in these SCMMs is the near miss management process, as it’s generally recognized as a critical aspect for evaluating the maturity level of the safety culture characterizing an organization. Thus, after evaluating how SCMMs have been proposed in the current literature, this study aims to provide a first draft proposal of Near Miss Maturity Model, to support specifically companies in evaluating how their near mis management process is developed and how it could be improved. The purpose is to design a tool able to highlight potential gaps and weaknesses that could be improved for increasing the safety culture of an organization. Safety culture strategies, like Safety I, Safety II and Safety-III, were applied to develop this innovative tool
Search for Higgs boson decays into a pair of pseudoscalar particles in the γγτhadτhad final state using pp collisions at sqrt(s) = 13 TeV with the ATLAS detector
No full textA search for exotic decays of the 125 GeV Higgs boson (H) into a pair of new spin-0 particles, H→aa, where one decays into a photon pair (γγ) and the other into a τ-lepton pair (ττ), is presented. Hadronic decays of the τ-leptons (τhad) are considered and reconstructed using a dedicated tagger for collimated τ-lepton pairs. The search uses 140 fb-1 of proton-proton collision data at a centre-of-mass energy of sqrt(s) =13 TeV recorded between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider. The search is performed in the mass range of the a boson between 10 GeV and 60 GeV. No significant excess of events is observed above the Standard Model background expectation. Model-independent upper limits at 95% confidence level are set on the branching ratio of the Higgs boson to the γγττ final state, B(H →aa→γγττ), ranging from 0.2% to 2%, depending on the a-boson mass hypothesis
