434 research outputs found

    Deterministic Monotone Algorithms for Scheduling on Related Machines

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    We consider the problem of designing monotone deterministic algorithms for scheduling tasks on related machines in order to minimize the makespan. Several recent papers showed that monotonicity is a fundamental property to design truthful mechanisms for this scheduling problem. We give both theoretical and experimental results. First of all we consider the case of two machines when speeds of the machines are restricted to be powers of a given constant c>0. We prove that algorithm Largest Processing Time (LPT) is monotone for any c≥2 while it is not monotone for c≤1.78; algorithm List Scheduling (LS), instead, is monotone only for c>2. In the case of m>2 machines we restrict our attention to the class of “greedy-like” monotone algorithms defined in [Vincenzo Auletta, Roberto De Prisco, Paolo Penna, Giuseppe Persiano, Deterministic truthful approximation mechanisms for scheduling related machines, in: Proceedings of 21st Annual Symposium on Theoretical Aspects of Computer Science. STACS ’04, in: Lecture Notes in Computer Science, vol. 2996, Springer, 2004, pp. 608–619]. It has been shown that greedy-like monotone algorithms can be used to design a family of 2+ε-approximate truthful mechanisms. In particular, in [Vincenzo Auletta, Roberto De Prisco, Paolo Penna, Giuseppe Persiano, Deterministic truthful approximation mechanisms for scheduling related machines, in: Proceedings of 21st Annual Symposium on Theoretical Aspects of Computer Science. STACS ’04, in: Lecture Notes in Computer Science, vol. 2996, Springer, 2004, pp. 608–619], the greedy-like algorithm Uniform is proposed and it is proved that it is monotone when machine speeds are powers of a given integer constant c>0. In this paper we propose a new algorithm, called Uniform_RR, that is still monotone when speeds are powers of a given integer constant c>0 and we prove that its approximation factor is not worse than that of Uniform. We also experimentally compare the performance of Uniform, Uniform_RR, LPT, and several other monotone and greedy-like heuristics

    A first experimental test of de Broglie-Bohm theory against standard quantum mechanics

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    De Broglie - Bohm (dBB) theory is a deterministic theory, built for reproducing almost all Quantum Mechanics (QM) predictions, where position plays the role of a hidden variable. It was recently shown that different coincidence patterns are predicted by QM and dBB when a double slit experiment is realised under specific conditions and, therefore, an experiment can test the two theories. In this letter we present the first realisation of such a double slit experiment by using correlated photons produced in type I Parametric Down Conversion. Our results confirm QM contradicting dBB predictions

    Ultrasonographic assessment of normal jugular veins in Standardbred horses

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    Ultrasonography (US) is the recommended imaging technique to evaluate jugular veins. This prospective randomized clinical study was designed to collect a series of B-mode US measurements of manually distended jugular veins in healthy Italian Standardbreds and to find possible correlations between ultrasound measurements and animal morphometric characteristics. Forty-two horses, eight males and 34 females (range 3-22 years; bodyweight 494.4 ± 41.7 kg), were included in the study. The diameters and wall thicknesses of both jugular veins were measured at three different sites of the neck. The differences in ultrasound measurements based on scans, age, gender, side, and site of the neck were evaluated by ANOVA or by the Kruskal-Wallis test. The effects of the morphometric measures on each ultrasound parameter were evaluated by MANOVA (P < 0.05)

    The use of platelet-rich plasma for treatment of tenodesmic lesions in horses: A systematic review and meta-analysis of clinical and experimental data

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    The use of platelet-rich plasma (PRP) to enhance tenodesmic lesion healing has been questioned over the years. The aim of this study was to evaluate current literature to establish the effectiveness of PRP for treating tenodesmic lesions through a systematic review, in accordance with the PRISMA guidelines, and a meta-analysis. Studies comparing PRP with placebo or other treatments for horses with tenodesmic injuries or evaluated PRP effect on tendon and ligament explants were included. Outcomes were clinical, ultrasound, histologic, molecular evaluation, and adverse effects. Two authors independently extracted data and assessed each study’s risk of bias. Treatment effects were evaluated using risk ratios for dichotomous data, together with 95% CI. Data were pooled using the random-effects model. The quality of the evidence for each outcome was assessed using GRADE criteria. Twenty-four trials met inclusion criteria for systematic review, while fifteen studies were included in the meta-analysis. Results showed no significant differences in the outcomes between PRP and control groups. Finally, there is no definitive evidence that PRP enhances tendons and ligaments healing. Therefore, there is a need for more controlled trials to draw a firmer conclusion about the efficacy of PRP as a treatment for tenodesmic lesions in the horse

    Ultrasonographic assessment of normal jugular veins in Standardbred horses

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    Ultrasonography (US) is the recommended imaging technique to evaluate jugular veins. This prospective randomized clinical study was designed to collect a series of B-mode US measurements of manually distended jugular veins in healthy Italian Standardbreds and to find possible correlations between ultrasound measurements and animal morphometric characteristics. Forty-two horses, eight males and 34 females (range 3-22\u2009years; bodyweight 494.4\u2009\ub1\u200941.7\u2009kg), were included in the study. The diameters and wall thicknesses of both jugular veins were measured at three different sites of the neck. The differences in ultrasound measurements based on scans, age, gender, side, and site of the neck were evaluated by ANOVA or by the Kruskal-Wallis test. The effects of the morphometric measures on each ultrasound parameter were evaluated by MANOVA (P\u2009&lt;\u20090.05)

    Decellularized skeletal muscles support the generation of in vitro neuromuscular tissue models

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    Decellularized skeletal muscle (dSkM) constructs have received much attention in recent years due to the versatility of their applications in vitro. In search of adequate in vitro models of the skeletal muscle tissue, the dSkM offers great advantages in terms of the preservation of native-tissue complexity, including three-dimensional organization, the presence of residual signaling molecules within the construct, and their myogenic and neurotrophic abilities. Here, we attempted to develop a 3D model of neuromuscular tissue. To do so, we repopulated rat dSkM with human primary myogenic cells along with murine fibroblasts and we coupled them with organotypic rat spinal cord samples. Such culture conditions not only maintained multiple cell type viability in a long-term experimental setup, but also resulted in functionally active construct capable of contraction. In addition, we have developed a customized culture system which enabled easy access, imaging, and analysis of in vitro engineered co-cultures. This work demonstrates the ability of dSkM to support the development of a contractile 3D in vitro model of neuromuscular tissue fit for long-term experimental evaluations
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