149 research outputs found

    Well-posedness and long-time behavior for a class of doubly nonlinear equations

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    This paper addresses a doubly nonlinear parabolic inclusion of the form A(ut)+B(u)fA(u_t)+B(u)\ni f. Existence of a solution is proved under suitable monotonicity, coercivity, and structure assumptions on the operators AA and BB, which in particular are both supposed to be subdifferentials of functionals on L2(Ω)L^2(\Omega). Moreover, under additional hypotheses on BB, uniqueness of the solution is proved. Finally, a characterization of ω\omega-limit sets of solutions is given and we investigate the convergence of trajectories to limit points

    Global attractors for gradient flows in metric spaces

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    We develop the long-time analysis for gradient flow equations in metric spaces. In particular, we consider two notions of solutions for metric gradient flows, namely energy and generalized solutions. While the former concept coincides with the notion of curves of maximal slope, we introduce the latter to include limits of time-incremental approximations constructed via the Minimizing Movements approach. For both notions of solutions we prove the existence of the global attractor. Since the evolutionary problems we consider may lack uniqueness, we rely on the theory of generalized semiflows introduced by J.M. Ball. The notions of generalized and energy solutions are quite flexible and can be used to address gradient flows in a variety of contexts, ranging from Banach spaces to Wasserstein spaces of probability measures. We present applications of our abstract results by proving the existence of the global attractor for the energy solutions both of abstract doubly nonlinear evolution equations in reflexive Banach spaces, and of a class of evolution equations in Wasserstein spaces, as well as for the generalized solutions of some phase-change evolutions driven by mean curvature

    Weighted Energy-Dissipation principle for gradient flows in metric spaces

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    This paper develops the so-called Weighted Energy-Dissipation (WED) variational approach for the analysis of gradient flows in metric spaces. This focuses on the minimization of the parameter-dependent global-in-time functional of trajectories \mathcal{I}_\varepsilon[u] = \int_0^{\infty} e^{-t/\varepsilon}\left( \frac12 |u'|^2(t) + \frac1{\varepsilon}\phi(u(t)) \right) \dd t, featuring the weighted sum of energetic and dissipative terms. As the parameter ε\varepsilon is sent to~00, the minimizers uεu_\varepsilon of such functionals converge, up to subsequences, to curves of maximal slope driven by the functional ϕ\phi. This delivers a new and general variational approximation procedure, hence a new existence proof, for metric gradient flows. In addition, it provides a novel perspective towards relaxation

    Upper Respiratory Tract Infections in Sport and the Immune System Response. A Review

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    Immunity is the consequence of a complex interaction between organs and the environment. It is mediated the interaction of several genes, receptors, molecules, hormones, cytokines, antibodies, antigens, and inflammatory mediators which in turn relate and influence the psychological health. The immune system response of heavily trained athletes resembles an even more complex conditions being theorized to follow a J or S shape dynamics at times. High training loads modify the immune response elevating the biological markers of immunity and the body susceptibility to infections. Heavy training and/or training in a cold environment increase the athletes' risk to develop Upper Respiratory Tract Infections (URTIs). Therefore, athletes, who are considered healthier than the normal population, are in fact more prone to infections of the respiratory tract, due to lowering of the immune system in the time frames subsequent heavy training sessions. In this revision we will review the behavioral intervention, including nutritional approaches, useful to minimize the "open window" effect on infection and how to cope with stressors and boost the immune system in athletes

    Multidisciplinary Management of Elderly Cancer Patients:The Radiation Oncologist's Point of View

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    The complexity of oncological treatments for elderly patients starts from the very beginning, since the definition of "geriatric patient" is not univocal. From the point of view of public health, the problem is of the outmost importance

    Cycling training effects on fat metabolism blood parameters

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    BACKGROUND: Study the acute and middle term (4 weeks training) effect of cycling training on fat blood hematological parameters, urine, fatigue, and general health in recreational well-trained cyclists. METHODS: Nineteen cyclists underwent five blood sample collections: before and after an incremental maximal ramp test 7 days before day 0 (D-0); before and after 1 hour exhaustion trial test at baseline (D-0); and after 28 days of training (D-28). Age 34.5 years (\ub19.5); weight 74.87 kg (\ub16.6); height 177.3 cm (\ub15.2); BMI 26.3 (\ub14.9); VO2max 53.75 mL/kg/ min (\ub16.01); distance cycled 314.7 km/week (\ub1137.1). RESULTS: Acute effect was strong elevating WBC from 6.27\ub12.34 to 9.01\ub13.63 7103/\ub5L, an increase in LDL and total CHOL, in this respect, existing literature is controversial. No changes in body weight or blood pressure was observed after 1 month of regular training albeit lipid profile significantly improved, as well as GOT. CONCLUSIONS: Effect of a short incremental bout of exercise was to temporary elevated all the blood parameters except MCH and MCHC. A month of intensive training (distance cycled: 314.7\ub1137.1 km/week) significantly improved blood lipids profile with no permanent effect on WBC, blood pressure or body weight, but improved post effort lactate concentration and fatigue perception. Hematuria is confirmed to be a rare occurrence in recreational cyclists. Data can be useful for training monitoring and comparisons with similar groups of athletes, where there is a lack of information in literature and for comparing exercise effects

    Renaissance mercurial therapy in the mummies of Saint Domenico Maggiore in Naples: a palaeopathological and palaeotoxicological approach

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    AbstractThis study was designed to evaluate the use of mercury therapy in the Italian noble classes of the Renaissance through the toxicological analysis of hair content. Mercury has stability and a long half-life in hair, representing a great resource not only for forensic toxicological analysis but also for archaeological research on mercurial exposure in past populations. The hair of fourteen mummified individuals of the Aragon and vice-royal court of Naples, buried in the Neapolitan Basilica of Saint Domenico Maggiore (15–18th centuries), was analysed by atomic absorption spectroscopy (AAS) and flame emission spectroscopy (FES). Out of the fourteen individuals, four presented mercury concentrations in the hair washing liquid indicating external perimortem application (in one case clearly linked to embalming, in three cases probably associated with topical therapeutic practices), three showed no traces of mercury, and seven had mercury values in hair ranging from 411 to 47 ppm, which indicate prolonged exposure in life to the metal. The historical identification of most of the mummified bodies with important nobles of Naples has allowed to compare the toxicological analyses with the nosography of the individuals and with the palaeopathological results deriving from the direct study of their bodies. Prolonged exposure in life to the metal was most likely due to mercurial anti-syphilitic therapy, as a consequence of its indiscriminate use in Renaissance therapies and, indirectly, as an effect of the extraordinary spread of venereal syphilis in the Italian upper classes during the "epidemic" phase of the disease

    Bone mineral density and hormonal status in adolescent athletic girls

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    The aim of this study was to determine the relationships of bone mineral density (BMD) and content (BMC) with selected fasting hormones in adolescents with different exercise training patterns. The participants were female athletes of weight-loaded (n=23) and weight-supported (n=24) sports, and 33 non-athletic girls aged 13–15 years. BMD (g/cm2) and BMC (g) at the femoral neck (FN) and lumbar spine (LS) were measured. Venous blood samples were drawn to determine the concentration of insulin-like growth factor-1 (IGF-1), IGF binding protein-3 (IGFBP-3), estradiol, visfatin, adiponectin, leptin, insulin, and glucose. After adjusting for age, height, and body mass, the relationships of BMD variables with IGF-1, IGF-1/IGFBP-3 molar ratio, estradiol, and leptin levels remained significant only in the weight-loaded sport group (r=0.41–0.60; p<0.05). Adiponectin was inversely correlated to FN and LS BMD and BMC (r=–0.47–0.62; p<0.05) in weight-supported sport group only, but after adjustments for age, height, and body mass, these associations disappeared. In this study, concentrations of visfatin, a fairly new adipocytokine, were not related to bone parameters in adolescent girls with different training patterns
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