7 resultados para COMPARISON WITH QCD

em AMS Tesi di Dottorato - Alm@DL - Università di Bologna


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The aim of this PhD thesis is the study of the nuclear properties of radio loud AGN. Multiple and/or recent mergers in the host galaxy and/or the presence of cool core in galaxy clusters can play a role in the formation and evolution of the radio source. Being a unique class of objects (Lin & Mohr 2004), we focus on Brightest Cluster Galaxies (BCGs). We investigate their parsec scale radio emission with VLBI (Very Long Baseline Interferometer) observations. From literature or new data , we collect and analyse VLBA (Very Long Baseline) observations at 5 GHz of a complete sample of BCGs and ``normal'' radio galaxies (Bologna Complete Sample , BCS). Results on nuclear properties of BCGs are coming from the comparison with the results for the Bologna COmplete Sample (BCS). Our analysis finds a possible dichotomy between BCGs in cool-core clusters and those in non-cool-core clusters. Only one-sided BCGs have similar kinematic properties with FRIs. Furthermore, the dominance of two-sided jet structures only in cooling clusters suggests sub-relativistic jet velocities. The different jet properties can be related to a different jet origin or to the interaction with a different ISM. We larger discuss on possible explanation of this.

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Background and rationale for the study. This study investigated whether human immunodeficiency virus (HIV) infection adversely affects the prognosis of patients diagnosed with hepatocellular carcinoma (HCC).Thirty-four HIV-positive patients with chronic liver disease, consecutively diagnosed with HCC from 1998 to 2007 were one-to-one matched with 34 HIV negative controls for: sex, liver function (Child-Turcotte-Pugh class [CTP]), cancer stage (BCLC model) and, whenever possible, age, etiology of liver disease and modality of cancer diagnosis. Survival in the two groups and independent prognostic predictors were assessed. Results. Among HIV patients 88% were receiving HAART. HIV-RNA was undetectable in 65% of cases; median lymphocyte CD4+ count was 368.5/mmc. Etiology of liver disease was mostly related to HCV infection. CTP class was: A in 38%, B in 41%, C in 21% of cases. BCLC cancer stage was: early in 50%, intermediate in 23.5%, advanced in 5.9%, end-stage in 20.6% of cases. HCC treatments and death causes did not differ between the two groups. Median survival did not differ, being 16 months (95% CI: 6-26) in HIV positive and 23 months (95% CI: 5-41) in HIV negative patients (P=0.391). BCLC cancer stage and HCC treatment proved to be independent predictors of survival both in the whole population and in HIV patients. Conclusions. Survival of HIV infected patients receiving antiretroviral therapy and diagnosed with HCC is similar to that of HIV negative patients bearing this tumor. Prognosis is determined by the cancer bulk and its treatment.

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In this thesis the analysis to reconstruct the transverse momentum p_{t} spectra for pions, kaons and protons identified with the TOF detector of the ALICE experiment in pp Minimum Bias collisions at $\sqrt{s}=7$ TeV was reported. After a detailed description of all the parameters which influence the TOF PID performance (time resolution, calibration, alignment, matching efficiency, time-zero of the event) the method used to identify the particles, the unfolding procedure, was discussed. With this method, thanks also to the excellent TOF performance, the pion and kaon spectra can be reconstructed in the 0.5comparison with the spectra obtained with a $3\sigma$ cut PID procedure, was reported, showing an agreement within 5%. The estimation of the systematic uncertainties was described. The reported spectra provide very useful information to tune the Monte Carlo generators that, as was shown, are not able to describe $\pi$, $K$ and $p$ production over the full momentum range. The same limitation for the theoretical models in describing the data was observed when comparing with the Monte Carlo predictions the $K/\pi$ and $p/\pi$ ratios, as obtained with the TOF analysis. Finally, the comparison between the TOF results and the spectra obtained with analyses that use other ALICE PID detectors and techniques to extend the identified spectra to a wider $p_{t}$ range was reported, showing an agreement within 6\%.

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The objective of this thesis was to improve the commercial CFD software Ansys Fluent to obtain a tool able to perform accurate simulations of flow boiling in the slug flow regime. The achievement of a reliable numerical framework allows a better understanding of the bubble and flow dynamics induced by the evaporation and makes possible the prediction of the wall heat transfer trends. In order to save computational time, the flow is modeled with an axisymmetrical formulation. Vapor and liquid phases are treated as incompressible and in laminar flow. By means of a single fluid approach, the flow equations are written as for a single phase flow, but discontinuities at the interface and interfacial effects need to be accounted for and discretized properly. Ansys Fluent provides a Volume Of Fluid technique to advect the interface and to map the discontinuous fluid properties throughout the flow domain. The interfacial effects are dominant in the boiling slug flow and the accuracy of their estimation is fundamental for the reliability of the solver. Self-implemented functions, developed ad-hoc, are introduced within the numerical code to compute the surface tension force and the rates of mass and energy exchange at the interface related to the evaporation. Several validation benchmarks assess the better performances of the improved software. Various adiabatic configurations are simulated in order to test the capability of the numerical framework in modeling actual flows and the comparison with experimental results is very positive. The simulation of a single evaporating bubble underlines the dominant effect on the global heat transfer rate of the local transient heat convection in the liquid after the bubble transit. The simulation of multiple evaporating bubbles flowing in sequence shows that their mutual influence can strongly enhance the heat transfer coefficient, up to twice the single phase flow value.

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The aim of the dissertation was to test the feasibility of a new psychotherapeutic protocol for treating children and adolescents with mood and anxiety disorders: Child-Well-Being Therapy (CWBT). It originates from adult Well-Being Therapy protocol (WBT) and represents a conceptual innovation for treating affective disorders. WBT is based on the multidimensional model of well-being postulated by Ryff (eudaimonic perspective), in sequential combination with cognitive-behavioral therapy (CBT). Results showed that eudaimonic well-being was impaired in children with affective disorders in comparison with matched healthy students. A first open investigation aimed at exploring the feasibility of a 8-session CWBT protocol in a group of children with emotional and behavioural disorders has been implemented. Data showed how CWBT resulted associated to symptoms reduction, together with the decrease of externalizing problems, maintained at 1-year follow-up. CWBT triggered also an improvement in psychological well-being as well as an increasing flourishing trajectory over time. Subsequently, a modified and extended version of CWBT (12-sessions) has been developed and then tested in a controlled study with 34 patients (8 to 16 years) affected by mood and anxiety disorders. They were consecutively randomized into 3 different groups: CWBT, CBT, 6-month waiting list (WL). Both treatments resulted effective in decreasing distress and in improving well-being. Moreover, CWBT was associated with higher improvement in anxiety and showed a greater recovery rate (83%) than CBT (54%). Both groups maintained beneficial effects and CWBT group displayed a lower level of distress as well as a higher positive trend in well-being scores over time. Findings need to be interpret with caution, because of study limitations, however important clinical implications emerged. Further investigations should determine whether the sequential integration of well-being and symptom-oriented strategies could play an important role in children and adolescents’ psychotherapeutic options, fostering a successful adaptation to adversities during the growth process.

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Virgin olive oil(VOO) is a product characterized by high economic and nutritional values, because of its superior sensory characteristics and minor compounds (phenols and tocopherols) contents. Since the original quality of VOO may change during its storage, this study aimed to investigate the influence of different storage and shipment conditions on the quality of VOO, by studying different solutions such as filtration, dark storage and shipment inside insulated containers to protect it. Different analytical techniques were used to follow-up the quality changes during virgin olive oil storage and simulated shipments, in terms of basic quality parameters, sensory analysis and evaluation of minor components (phenolic compounds, diglycerides, volatile compounds). Four main research streams were presented in this PhD thesis: The results obtained from the first experimental section revealed that the application of filtration and/or clarification can decrease the unavoidable quality loss of the oil samples during storage, in comparison with unfiltered oil samples. The second section indicated that the virgin olive oil freshness, evaluated by diglycerides content, was mainly affected by the storage time and temperature. The third section revealed that fluctuation in temperature during storage may adversely affect the virgin olive oil quality, in terms of hydrolytic rancidity and oxidation quality. The fourth section showed that virgin olive oil shipped inside insulated containers showed lower hydrolytic and oxidation degradation than those without insulation cover. Overall, this PhD thesis highlighted that application of adequate treatment, such as filtration or clarification, in addition to a good protection against other external variables, such as temperature and light, will improve the stability of virgin olive oil during storage.

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Background. Clinical significance of multifocal pulmonary neuroendocrine proliferations (MNEP), including tumorlets and pulmonary neuroendocrine cell hyperplasia, in association with Typical Carcinoid (TC), is still debated. Methods. A large retrospective series of TC with long-term follow-up data prospectively collected from two institutions was evaluated. Recurrence or new TC development was followed-up. Patients with TC alone and MNEP+TC were compared. Results. 234 TC patients undergone surgery were included: 41 MNEP+TC (17.5%) and 193 TC alone (82.5%). In the MNEP+TC group older age (p<0.001), peripheral tumors (p=0.0032), smaller tumor size (p=0.011) and lymph-nodal spread (p=0.02) were observed in comparison with TC group. Relapses occurred in 8 patients (19.5%) in the MNEP+TC group and in 7 (3.6%) of the TC group. The 10-years progression-free survival were 96.1% in TC and 83.8% in MNEP+TC (p<0.001). After matching, in 36 pairs of patients a significantly higher 5-years progression-free survival was calculated for TC group (p<0.01). Furthermore the odds of belonging to MNEP+TC group was higher with work-related exposure to inhalant agents (p=0.008), asthma/bronchitis (p=0.002), emphysema, fibrosis and inflammatory status (p=0.032), micronodules on the chest CT scan and respiratory insufficiency (p=0.036). Conclusions. The identification of MNEP requires careful pathological examination and postoperative follow-up. MNEP seems to be an adverse prognostic factor in patients with synchronous TC. Therefore, suspicion of MNEP during the pre-operative assessment should not be underestimated, enabling changes in the surgical strategy.