Electric-magnetic duality in linearized Ho\v{r}ava-Lifshitz gravity

Known as a symmetry of vacuum Maxwell equations, the electric-magnetic duality can be lifted actually to a symmetry of an action. The Lagrangian of this action is written in terms of two vector potentials, one electric and one magnetic, and while it is manifestly invariant under duality rotations, it is not manifestly Lorentz covariant. This duality symmetry exists also in linearized gravity in four dimensions, and can be lifted off shell too. In $d$ dimensions, the link between linearized gravity and its dual can also be seen from the point of view of a parental action. This is defined by a first order Lagrangian (with the help of some auxiliary variables) that delivers both Fierz-Pauli theory and its dual. In this work we use this formalism to implement the electric-magnetic duality in the nonrelativistic deviation of Fierz-Pauli theory arising from Ho\v{r}ava-Lifshitz gravity. Because this theory breaks diffeomorphism invariance, one finds that such implementation includes some peculiarities.Comment: v1: 23 pages, 4 figures, edited with LaTeXila 2.4.0 and wxMaxima 12.04.0 for the graphics (Maxima version: 5.27.0). arXiv admin note: text overlap with arXiv:1306.1092 by other authors; v2: 24 pages, 4 figures, references added, negligence (leading to poor version management and miscommunication) rectified; v3: typos and grammar corrected, minor changes to uniformize convention

La riduzione del numero dei Comuni: un tema che meriterebbe maggiore attenzione

A differenza di quanto si è verificato in altri paesi europei, in Italia non ci si è adoperati per favorire la riduzione del numero dei Comuni: si è solo cercato di spingerli a costituire delle “Unioni”. Il problema – si sostiene nel lavoro presentando la situazione delle varie Regioni – andrebbe invece affrontato alla luce del fatto che circa un quarto degli ottomila Comuni ha meno di 1.000 abitanti, soglia che si riflette negativamente sulla possibilità di organizzare una efficiente gestione dei servizi pubblici.Piccoli comuni, Gestione servizi pubblici, Unione di Comuni

Profilo dell'immigrazione egiziana in Italia

The paper examines the issue of Egyptian migration to Italy, a phenomenon that has undoubtedly increased in recent years. It describes the main socio-demographic characteristics of the group and analyze its distribution in the Italian territory; evaluates the degree of integration of Egyptian immigrants in the Italian society; finally; envisages some opportunities for further enlargement of the Egyptian presence in Italy.International Migration, Immigrant workers, Foreign Immigration in

Emergent Noncommutative gravity from a consistent deformation of gauge theory

Starting from a standard noncommutative gauge theory and using the Seiberg-Witten map we propose a new version of a noncommutative gravity. We use consistent deformation theory starting from a free gauge action and gauging a killing symmetry of the background metric to construct a deformation of the gauge theory that we can relate with gravity. The result of this consistent deformation of the gauge theory is nonpolynomial in A_\mu. From here we can construct a version of noncommutative gravity that is simpler than previous attempts. Our proposal is consistent and is not plagued with the problems of other approaches like twist symmetries or gauging other groups.Comment: 18 pages, references added, typos fixed, some concepts clarified. Paragraph added below Eq. (77). Match published PRD version

Epi-mucosa fixation and autologous platelet-rich fibrin treatment in medication-related osteonecrosis of the jaw

Medication-related osteonecrosis of the jaw (MRONJ) frequently affects patients after treatments with bisphosphonates or denosumab, especially with high doses in patients with bone osteoporosis, neoplastic metastases, or possibly anti-angiogenic treatment for cancer. The aim of this article was to show a new treatment planning for stage 2 and stage 3 MRONJ using platelet-rich fibrin (PRF) at the surgical field to enhance healing in association with a new epi-mucosal fixation technique to prevent or treat mandibular fracture. Two cases were treated by epi-mucosa fixation and autologous PRF use for prevention of mandibular fracture risks related to necrotic bone resection or a narrow fracture reduction. Both cases were successfully treated by this new technique of epi-mucosa fixation combined with autologous PRF and achieved good results and good quality of life. Ability to wear prosthesis with good mastication in the absence of side effect such as infection, plate and screw mobilization, pain, and other disabilities or extension of necrosis was reported. After surgical removal of necrotic bone, no infection was detected without any extension of the necrosis

L’integrazione sensori-motoria nella Sclerosi Multipla: studio di correlazione dei parametri neurofisiologici, clinici e di neuroimaging in una coorte di pazienti affetti da forma recidivante-remittente

Introduction: Somatosensory temporal discrimination threshold (STDT) is a neurophysiological measure of sensory information processing. Through mechanisms of sensory gating, sensorimotor integration ensures continuous monitoring of sensory inflow to adjust motor plan and performance. Voluntary movement modulates STDT through the interplay between basal ganglia and thalamus in healthy controls (HC). Although it has been demonstrated that STDT is altered in patients with multiple sclerosis (MS), subcortical mechanisms of sensorimotor integration have never been explored. Aim of the study was to combine neurophysiological and magnetic resonance imaging (MRI) measures to investigate STDT modulation during movement execution in MS.  Methods: Subjects: Thirty-eight patients with relapsing-remitting MS (mean age 40,8±7,9 years), a median Expanded Disability Status Scale (EDSS) of 1.5 (range 0-3.5) and and 27 age-matched HC were recruited. Neurophysiological measures: To test STDT at the baseline we delivered couples of electric stimuli with a progressively increasing interstimulus interval. STDT was considered as the first of three consecutive intervals at which participants recognized the two stimuli as temporally separate. We then tested STDT at 0 ms, 100 ms and 200 ms after the onset of index-finger abduction. We recorded the kinematic features of the movement by using the SMART system. MRI measures: All participants underwent a 3T MRI protocol including 3D-T1 and T2-FLAIR images; we used the semi-automated software Jim (v5.0) for white matter (WM) lesions detection and FSL-FIRST for subcortical volume calculation.  For diffusion MR imaging we used DTI Fit to generate whole brain fractional anistrophy (FA) and mean diffusivity (MD). Results: Neurophysiological measures: STDT at baseline was higher in patients compared to HC( F=9.67, p=0.002) (Figure 1). During voluntary movement, the percentage time-related changes in STDT did not differ between patients and controls (p=0.06) (Figure 2) although mean movement velocity significantly decreased in patients (p=0.003) but not in HC (Figure 3). MRI measures: Subcortical volumes analysis showed that the volume of caudate nucleus was significantly decreased in patients with MS compared to HC (p=0.02). DTI parameters were altered in patients compared to HC: MD was increased in patients than HC in putamen (p=0.02), pallidum (p=0.04) and thalamus (p=0.04), while mean FA resulted decreased in patients group compared to HC in the pallidum (p=0.02). Correlations: STDT at baseline negatively correlated with thalamic volume (r=-0.38, p=0.02) and positevely correlated with EDSS scores (r=0.39, p=0.02). In patients, time-related changes in STDT (r=0.41, p=0.01) and mean velocity (r=0.42, p=0.02) positively correlated with putaminal volume (Figure 4). Lastly, we did not find any correlation between neurophysiological measures and WM lesion load.  Conclusions: Altered STDT is related to thalamic atrophy and not to WM damage in patients with MS. Although sensory gating is preserved in MS, motor performance deteriorates during the task. The relationship between putaminal volume, STDT changes and movement kinematics suggests a key role of the putamen in this integrative function. Overall, our results shed light on the role of basal ganglia in sensorimotor integration in MS and could represent the background for new multitasking rehabilitation approaches

L'emigrazione italiana verso i paesi della riva Sud del Mediterraneo dall'Unità d'Italia al 1925

Between 1876 and 1925, in a lapse that includes the years of the so-called first Italian emi-gration phase (from 1876 to 1914, ending with the “great emigration”, occurred between 1900 and 1914) and the next decade leading to the beginning of fascism, in our country there are about 260 thousand migrants heading towards the Mediterranean countries in Af-rica (Morocco, Algeria, Tunisia and Egypt). Most of them were illiterate farmers, mainly from the Southern regions of the peninsula. They were running away from their own villag-es due to a deep crisis of agriculture, aggravated in the south by the latifundium and a ma-laria plague affecting many coastal areas. The long-lasting industrial and commercial un-derdevelopment does not allow to absorb the excess of labor supply generated by the pri-mary sector. The paper analyzes the formation (and relevant consistency) of Italian com-munities on the southern shore of the Mediterranean favored by job opportunities created by infrastructure investments promoted by the French authorities in the Maghreb and the process of modernization launched by the viceroy of Egypt and then carried forward by the English Administration