5 resultados para Asymmetries

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


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The habenular nuclei are diencephalic structures present in Vertebrates and they form, with the associated fiber systems, a part of the system that connects the telencephalon to the ventral mesencephalon (Concha M. L. and Wilson S. W., 2001). In representative species of almost all classes of Vertebrates the habenular nuclei are asymmetric, both in terms of size and of neuronal and neurochemical organization, although different types of asymmetry follow different evolutionary courses. Previous studies have analyzed the spread and diversity of the asymmetry in species for which data are not clear (Kemali M. et al., 1980). Notwithstanding that, it’s still not totally understood the evolution of the phenomenon, and the ontogenetic mechanisms that have led to the habenular asymmetry development are not clear (Smeets W.J. et al., 1983). For the present study 14 species of Elasmobranchs and 15 species of Teleostean have been used. Brains removed from the animals have been fixed using 4% paraformaldehyde in phosphate buffer; brains have been analyzed with different tecniques, and I used histological, immunohistochemical and ultrastructural analysis to describe this asymmetry. My results confirm data previously obtained studying other Elasmobranchs species, in which the left habenula is larger than the right one; the Teleostean show some slightly differences regarding the size of the habenular ganglia, in some species, in which the left habenular nucleus is larger than the right. In the course of studies, a correlation between the habits of life and the diencephalic asymmetry seems to emerge: among the Teleostean analyzed, the species with benthic life (like Lepidorhombus boscii, Platichthys flesus, Solea vulgaris) seem to possess a slight asymmetry, analogous to the one of the Elasmobranchs, while in the other species (like Liza aurata, Anguilla anguilla, Trisopterus minutus) the habenulae are symmetrical. However, various aspects of the neuroanatomical asymmetries of the epithalamus have not been deepened in order to obtain a complete picture of the evolution of this phenomenon, and new searches are needed to examine the species without clear asymmetry, in order to understand the spread and the diversity of the asymmetry among the habenulae between the Vertebrates.

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The production rate of $b$ and $\bar{b}$ hadrons in $pp$ collisions are not expected to be strictly identical, due to imbalance between quarks and anti-quarks in the initial state. This phenomenon can be naively related to the fact that the $\bar{b}$ quark produced in the hard scattering might combine with a $u$ or $d$ valence quark from the colliding protons, whereas the same cannot happen for a $b$ quark. This thesis presents the analysis performed to determine the production asymmetries of $B^0$ and $B^0_s$. The analysis relies on data samples collected by the LHCb detector at the Large Hadron Collider (LHC) during the 2011 and 2012 data takings at two different values of the centre of mass energy $\sqrt{s}=7$ TeV and at $\sqrt{s}=8$ TeV, corresponding respectively to an integrated luminosity of 1 fb$^{-1}$ and of 2 fb$^{-1}$. The production asymmetry is one of the key ingredients to perform measurements of $CP$ violation in b-hadron decays at the LHC, since $CP$ asymmetries must be disentangled from other sources. The measurements of the production asymmetries are performed in bins of $p_\mathrm{T}$ and $\eta$ of the $B$-meson. The values of the production asymmetries, integrated in the ranges $4 < p_\mathrm{T} < 30$ GeV/c and $2.5<\eta<4.5$, are determined to be: \begin{equation} A_\mathrm{P}(\B^0)= (-1.00\pm0.48\pm0.29)\%,\nonumber \end{equation} \begin{equation} A_\mathrm{P}(\B^0_s)= (\phantom{-}1.09\pm2.61\pm0.61)\%,\nonumber \end{equation} where the first uncertainty is statistical and the second is systematic. The measurement of $A_\mathrm{P}(B^0)$ is performed using the full statistics collected by LHCb so far, corresponding to an integrated luminosity of 3 fb$^{-1}$, while the measurement of $A_\mathrm{P}(B^0_s)$ is realized with the first 1 fb$^{-1}$, leaving room for improvement. No clear evidence of dependences on the values of $p_\mathrm{T}$ and $\eta$ is observed. The results presented in this thesis are the most precise measurements available up to date.

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Charmless charged two-body B decays are sensitive probes of the CKM matrix, that parameterize CP violation in the Standard Model (SM), and have the potential to reveal the presence of New Physics. The framework of CP violation within the SM, the role of the CKM matrix, with its basic formalism, and the current experimental status are presented. The theoretical tools commonly used to deal with hadronic B decays and an overview of the phenomenology of charmless two-body B decays are outlined. LHCb is one of the four main experiments operating at the Large Hadron Collider (LHC), devoted to the measurement of CP violation and rare decays of charm and beauty hadrons. The LHCb detector is described, focusing on the technologies adopted for each sub-detector and summarizing their performances. The status-of-the-art of the LHCb measurements with charmless two-body B decays is then presented. Using the 37/pb of integrated luminosity collected at sqrt(s) = 7 TeV by LHCb during 2010, the direct CP asymmetries ACP(B0 -> Kpi) = −0.074 +/- 0.033 +/- 0.008 and ACP(Bs -> piK) = 0.15 +/- 0.19 +/- 0.02 are measured. Using 320/pb of integrated luminosity collected during 2011 these measurements are updated to ACP(B0 -> Kpi) = −0.088 +/- 0.011 +/- 0.008 and ACP(Bs -> piK) = 0.27 +/- 0.08 +/- 0.02. In addition, the branching ratios BR(B0 -> K+K-) = (0.13+0.06-0.05 +/- 0.07) x 10^-6 and BR(Bs -> pi+pi-) = (0.98+0.23-0.19 +/- 0.11) x 10^-6 are measured. Finally, using a sample of 370/pb of integrated luminosity collected during 2011, the relative branching ratios BR(B0 -> pi+pi-)/BR(B0 -> Kpi) = 0.262 +/- 0.009 +/- 0.017, (fs/fd)BR(Bs -> K+K-)/BR(B0 -> Kpi)=0.316 +/- 0.009 +/- 0.019, (fs/fd)BR(Bs -> piK)/BR(B0 -> Kpi) = 0.074 +/- 0.006 +/- 0.006 and BR(Lambda_b -> ppi)/BR(Lambda_b -> pK)=0.86 +/- 0.08 +/- 0.05 are determined.

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Chromosomal and genetic syndromes are frequently associated with dental and cranio-facial alterations. The aim of our study is to identify and describe the dental and craniofacial alterations typical of six genetic and chromosomal syndromes examined. Materials and Methods- A dental visit was performed to 195 patients referred from Sant’Orsola Hospital of Bologna, University of Bologna, to Service of Special Need Dentistry, Dental Clinic, Department of Biomedical and Neuromotor Science, University of Bologna. The patients recruited were 137 females and 58 males, in an age range of 3-49 years (mean age of 13.8±7.4). The total sample consisted of subjects affected with Down Syndrome (n=133), Familiar Hypophosphatemic Ricket (n=10), Muscular Dystrophies (n=12), Noonan Syndrome (n=13), Turner Syndrome (n=17), Williams Syndrome(n=10). A questionnaire regarding detailed medical and dental history, oral health and dietary habits, was filled by parents/caregivers, or patients themselves when possible. The intra-oral and extra-oral examination valued the presence of facial asymmetries, oral habits, dental and skeletal malocclusions, dental formula, dental anomalies, Plaque Index (Silness&LÖe Index), caries prevalence (dmft/DMFT index), gingivitis and periodontal disease, and mucosal lesions. Radiographic examinations (Intraoral radiographies, Orthopanoramic, Skull teleradiography) were executed according to patient’s age and treatment planning. A review of literature about each syndrome and its dental and cranio-facial characteristics and about caries, hygiene status and malocclusion prevalence on syndromic and non-syndromic population was performed. Results - The data of all the patients were collected in the “Data Collection Tables” created for each syndrome. General anamnesis information, oral hygiene habits and dmft/DMFT, PI, malocclusion prevalence were calculated and compared to syndromic and non-syndromic population results found in literature. Discussions and conclusions - Guidelines of Special Care dentistry were indicated for each syndrome, in relation to each syndrome features and individual patient characteristics.

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L’elaborato si occupa di fare il punto in materia di indagini difensive a tre lustri dall’entrata in vigore della legge n. 397/2000, epilogo di un lungo processo evolutivo che ha visto da un lato, una gestazione faticosa e travagliata, dall’altro, un prodotto normativo accolto dagli operatori in un contesto di scetticismo generale. In un panorama normativo e giurisprudenziale in continua evoluzione, i paradigmi dettati dagli artt. 24 e 111 della Costituzione, in tema di diritto alla difesa e di formazione della prova penale secondo il principio del contraddittorio tra le parti, in condizioni di parità, richiedono che il sistema giustizia offra sia all’indagato che all’imputato sufficienti strumenti difensivi. Tenuto conto delle diversità che caratterizzano naturalmente i ruoli dell’accusa e della difesa che impongono asimmetrie genetiche inevitabili, l’obiettivo della ricerca consiste nella disamina degli strumenti idonei a garantire il diritto alla prova della difesa in ogni stato e grado del procedimento, nel tentativo di realizzare compiutamente il principio di parità accusa - difesa nel processo penale. La ricerca si dipana attraverso tre direttrici: l’analisi dello statuto sulle investigazioni difensive nella sua evoluzione storica sino ai giorni nostri, lo studio della prova penale nel sistema americano e, infine, in alcune considerazioni finali espresse in chiave comparatistica. Le suggestioni proposte sono caratterizzate da un denominatore comune, ovvero dal presupposto che per contraddire è necessario conoscere e che solo per tale via sia possibile, finalmente, riconoscere il diritto di difendersi indagando.