3,256 research outputs found

    Methodologies for self-organising systems:a SPEM approach

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    We define ’SPEM fragments’ of five methods for developing self-organising multi-agent systems. Self-organising traffic lights controllers provide an application scenario

    Equidistribution of the Fekete points on the sphere

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    The Fekete points are the points that maximize a Vandermonde-type determinant that appears in the polynomial Lagrange interpolation formula. They are well suited points for interpolation formulas and numerical integration. We prove the asymptotic equidistribution of the Fekete points in the sphere. The way we proceed is by showing their connection with other array of points, the Marcinkiewicz-Zygmund arrays and the interpolating arrays, that have been studied recently

    Equidistribution of the Fekete points on the sphere

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    The Fekete points are the points that maximize a Vandermonde-type determinant that appears in the polynomial Lagrange interpolation formula. They are well suited points for interpolation formulas and numerical integration. We prove the asymptotic equidistribution of the Fekete points in the sphere. The way we proceed is by showing their connection with other array of points, the Marcinkiewicz-Zygmund arrays and the interpolating arrays, that have been studied recently

    Information theory in high energy physics (extensive and nonextensive approach)

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    The application of information theory approach (both in its extensive and nonextensive versions) to high energy multiparticle processes is discussed and confronted with experimental data on e+e- annihilation processes, pp and \bar{p}p scatterings and heavy ion collisions.Comment: 6 pages - contribution to International Workshop on: Trends and Perspectives in Extensive and Non-Extensive Statistical Mechanics (in Honour to the q-60th Birthday of Constantino Tsallis) November 19-21, 2003, Angra dos Reis, Brazil Small corrections added. To be published in Physica A (2004

    Levels of salivary immunoglobulins and periodontal evaluation in smoking patients

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    Abstract Objective: The aim of this study was to assess the level of salivary immunoglobulins and periodontal status in smokers and non-smokers. Materials and methods: Unstimulated saliva of 30 subjects (mean age 24.2 ± 3.5 years) who were smokers (test group) and of 30 subjects (mean age 25.3 ± 3.8 years) who were non-smokers (control group) was collected and centrifugated; IgA, IgG, and IgM were measured with the colorimetric immunoenzymatic method. Moreover, the following periodontal clinical parameters were recorded for each subject: plaque index (PI), gingival index (GI), probing depth (PD), and clinical attachment level (CAL). Results: A significantly (p< 0.05) lower Ig level was observed in smoking patients (IgA: 20.0 ± 1.2 mg/dl; IgM: 19.5 ± 1.6 mg/dl; IgG: 8.1 ± 1.4 mg/dl) compared to levels in the non-smoking control group (IgA: 234.1 ± 65.2 mg/dl; IgM: 121.0 ± 31.7 mg/dl; IgG: 1049.4 ± 102 mg/dl). In the test group, PI (2.2 ± 0.3), GI (2.4 ±0.5), PD (49.3 ± 9.2%), and CAL (49.3 ± 4.6%) were higher (p< 0.05) than those observed in the control group (PI: 0.8 ± 0.4; GI: 0.7 ± 0.3; PD: 10.6 ± 2.4%; CAL: 3.1 ± 0.8%). Conclusion: Smoking subjects showed lower levels of salivary IgA, IgG, and IgM and a worse periodontal condition than non-smoking subjects. On the base of our study, as smoking subjects also had lower levels of IgA, IgG, and IgM in their saliva than non-smoking subjects, despite the fact that there is little evidence that the salivary Igs have a protective action against periodontitis and that the whole saliva does not result in whole from the salivary glands, it can be concluded that the deteriorated periodontal health conditions of these patients can be attributed in part to a lowering of the host’s defense due to a decrease in the quantity of Igs in salivary fluid

    Levitation Simulator: Prototyping Ultrasonic Levitation Interfaces in Virtual Reality

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    We present the Levitation Simulator, a system that enables researchers and designers to iteratively develop and prototype levitation interface ideas in Virtual Reality. This includes user tests and formal experiments. We derive a model of the movement of a levitating particle in such an interface. Based on this, we develop an interactive simulation of the levitation interface in VR, which exhibits the dynamical properties of the real interface. The results of a Fitts' Law pointing study show that the Levitation Simulator enables performance, comparable to the real prototype. We developed the first two interactive games, dedicated for levitation interfaces: LeviShooter and BeadBounce, in the Levitation Simulator, and then implemented them on the real interface. Our results indicate that participants experienced similar levels of user engagement when playing the games, in the two environments. We share our Levitation Simulator as Open Source, thereby democratizing levitation research, without the need for a levitation apparatus.Comment: 12 pages, 14 figures, CHI'2

    Network polarization, filter bubbles, and echo chambers: An annotated review of measures and reduction methods

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    Polarization arises when the underlying network connecting the members of a community or society becomes characterized by highly connected groups with weak inter-group connectivity. The increasing polarization, the strengthening of echo chambers, and the isolation caused by information filters in social networks are increasingly attracting the attention of researchers from different areas of knowledge such as computer science, economics, social and political sciences. This work presents an annotated review of network polarization measures and models used to handle the polarization. Several approaches for measuring polarization in graphs and networks were identified, including those based on homophily, modularity, random walks, and balance theory. The strategies used for reducing polarization include methods that propose edge or node editions (including insertions or deletions, as well as edge weight modifications), changes in social network design, or changes in the recommendation systems embedded in these networks.Comment: Corrected a typo in Section 3.2; the rest remains unchange

    A multistage combined approach to promote diabetic wound healing in COVID-19 era

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    When diabetes mellitus is not properly controlled with drugs and a healthy lifestyle, it exposes patients with advanced peripheral arterial disease or critical limb ischaemia (CLI) to the most serious complications, in particular lower limb ulcers. Surgical or endovascular treatments represent the first line of intervention; in addition, the adequate management of ulcers can guarantee not only a faster wound healing but also the improvement of the patient's prognosis. To speed up this process, negative pressure wound therapy (NPWT), platelet-rich plasma (PRP), and other advanced moist wound dress- ing have been proposed. During Coronavirus disease 2019 (COVID-19) pan- demic, many patients with CLI and diabetes mellitus had difficult access to advanced treatments with a significant reduction in life expectancy. We report the cases of patients with non-healing ulcers and CLI treated with an empiric multistage approach after successful endovascular revascularisation; the post- operative course was eventful in all patients, and foot ulcers are currently in an advanced state of healing. The association between adequate revascularisation, systemic anti-inflammatory, and antibiotic therapy with the multistage advanced medications ensures healing of ulcers, limb salvage, and improvement of patient prognosis

    Durability of adhesion between an adhesive and post-space dentin: Push-out evaluation at one and six months.

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    Aims The aim of this study was to investigate, by means of the push-out test, the bond of Prime & Bond NT at various post-space dentin locations and the influence of time of water storage on bond strength values. Methods 30 single-rooted teeth were used for the bond strength measurement. In each tooth fiber posts were cemented with the commercial bonding system “Prime & Bond NT” in combination with the resin-based filling material “Opticore Cure Core Composite”. After 24 h (group A: 10 roots), 1 month (group B: 10 roots), and 6 months (group C: 10 roots) of water storage, the specimens were sectioned in 1 mm-thick slices for the push-out test. The data were divided into three regions (coronal/middle/apical) and analyzed using Kruskal-Wallis Test and Mann-Whitney U Test (p<0.05). Results The bond strength values registered did not show statistically significant differences within group A and C; within group B statistically significant differences were found between the coronal and the middle thirds and between the coronal and the apical third. The apical bond strength values did not show any statistically significant difference among the three groups (Kruskal-Wallis test); in the middle thirds a statistically significant difference was found at 6 months when compared with the 24 h and 1-month samples. In the coronal thirds was found a statistically significant difference between 1 month and 6 months. Analysis of the specimens under optical microscope revealed a prevalence of adhesive failures between fiber post and root dentin. Conclusions Bond strength values are lower at the apical third. Over time the adhesion of the fiberpost/luting cement/post-space dentin does not remain stable
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