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“Pubblico” e “opinione pubblica”: osservazioni su due luoghi comuni del lessico politico italiano del Settecento
Sandro Landi
Cromohs (Firenze) , 2008,
Abstract: This article deals with the issue of the emergence of the “public” and the “public opinion” in the eighteen-century’s Italian political discourse. The emergence of these categories is connected with some structural transformations in the power’s ideology, in particular with the crisis of the traditional doctrine of the “arcana imperii”. The aim of this article is to underline the divergence between this discursive reality and the public sphere as a political and cultural reality in the eighteen-century’s Italy.
Chianti-an atomic database for euv emission lines
Enrico Landi
Revista mexicana de astronomía y astrofísica , 2000,
Abstract: CHIANTI contiene un conjunto de datos at omicos y probabilidades de transici on, cuidadosamente seleccionados, para calcular el espectro de emisi on de plasmas astrof sicos. Los datos contienen niveles at omicos, longitudes de onda, fuerzas de oscilador, probabilidades A de transici on y tasas de excitaci on colisional. Se provee un conjunto de programas que usan los datos para calcular el espectro, como funci on de la temperatura y la densidad, en el rango de longitudes de onda deseado. Se ha desarrollado un grupo de programas para hacer diagn osticos de plasmas astrof sicos. Se describe la base de datos CHIANTI actualizada y algunos de los resultados m as importantes que se han obtenido con ella.
Malignant transformation of cervical ostochondroma in patient with hereditary multiple exostoses (HME): Case report and review of the literature
ALESSANDRO LANDI
Journal of Solid Tumors , 2012, DOI: 10.5430/jst.v2n3p63
Abstract: Objectives: Hereditary multiple exosostes (HME) is a disorder characterized by the presence of multiple osteochondromas of the bone. Spinal involvement is rare, represent roughly 3% of cases and any portion of the vertebral body may be affected. Malignant transformation of the lesions is rare, but it is possible and is described in literature. Methods: We describe an unusual case of malignant transformation of a cervical osteochondromas arising from the articular complex, in a young girl affected by HME. The patient underwent surgery with a complete removal of the lesion, without any signs of recurrence seen at the MRI serial control at 3, 6 12 e 24 months. We analyzed the literature up to 2009 by focusing on the treatment and follow up. Results: Surgical removal is indicated for symptomatic spinal osteochondormas. The suspicion of malignant transformation is indicated by the sudden growth of the lesion after puberty, the presence of pain and the worsening of the neurological symptoms. Conclusions: In this case, radical surgery is imperative, given the close correlation with the malignant characteristics of the lesions, it is useful to have an extemporaneous histological examination. In the rare cases of malignant transformation, radical surgery is important for the prognosis and to prevent the progression of the lesions. If the complete removal is not possible, the therapy of choice is adjuvant radiotherapy.
Comparison of the Different Land Use on the Emission of Greenhouse Gases
Mahdipuor,Landi
Journal of Science and Technology of Agriculture and Natural Resources , 2010,
Abstract: An increase in the emission of greenhouse gases such as carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) from the soil surface to the atmosphere has been of worldwide concern over the last several decades. Carbon dioxide is recognized as a significant contributor to global warming and climatic change, accounting for 60% of total greenhouse effect. The aim of this research was to determinate the emission of greenhouse gases from different land under agricultural uses. Four types of agricultural land farm, including wheat field, canola field, citrus garden and fallow land were selected to investigate the fate of CO2 in these fields. Gas chromatography technique and close chamber method were used to analyze soil gas samples. Total carbon losses from soil in form of greenhouse gases was 4.47, 3.72, 3.38 and 1.89 Mg C ha-1 yr-1 for wheat field, canola field, citrus garden and fallow land, respectively. Total additional carbon to soil from biomass for wheat field and canola field was 4.1 and 4.6 Mg C ha-1 yr-1, respectively. ECB (ecosystem carbon budget) = ∑ C input - ∑ C output. For wheat field and canola field ECB was -0.37 and +0.88, respectively. This indicated that in wheat field carbon was lost and in canola field carbon was sequestrated. Under citrus garden due to changes in soil organic carbon form previous year has showed that carbon was sequestrated.
Spin-Hall effect with quantum group symmetry
Giovanni Landi
Physics , 2005, DOI: 10.1007/s11005-005-0040-8
Abstract: We construct a model of spin-Hall effect on a noncommutative 4 sphere with isospin degrees of freedom (coming from a noncommutative instanton) and invariance under a quantum orthogonal group. The corresponding representation theory allows to explicitly diagonalize the Hamiltonian and construct the ground state; there are both integer and fractional excitations. Similar models exist on higher dimensional noncommutative spheres and noncommutative projective spaces.
Noncommutative Spheres and Instantons
Giovanni Landi
Physics , 2003, DOI: 10.1007/11342786_1
Abstract: We report on some recent work on deformation of spaces, notably deformation of spheres, describing two classes of examples. The first class of examples consists of noncommutative manifolds associated with the so called $\theta$-deformations which were introduced out of a simple analysis in terms of cycles in the $(b,B)$-complex of cyclic homology. These examples have non-trivial global features and can be endowed with a structure of noncommutative manifolds, in terms of a spectral triple $(\ca, \ch, D)$. In particular, noncommutative spheres $S^{N}_{\theta}$ are isospectral deformations of usual spherical geometries. For the corresponding spectral triple $(\cinf(S^{N}_\theta), \ch, D)$, both the Hilbert space of spinors $\ch= L^2(S^{N},\cs)$ and the Dirac operator $D$ are the usual ones on the commutative $N$-dimensional sphere $S^{N}$ and only the algebra and its action on $\ch$ are deformed. The second class of examples is made of the so called quantum spheres $S^{N}_q$ which are homogeneous spaces of quantum orthogonal and quantum unitary groups. For these spheres, there is a complete description of $K$-theory, in terms of nontrivial self-adjoint idempotents (projections) and unitaries, and of the $K$-homology, in term of nontrivial Fredholm modules, as well as of the corresponding Chern characters in cyclic homology and cohomology.
Deconstructing Monopoles and Instantons
Giovanni Landi
Physics , 1998,
Abstract: We give a unifying description of the Dirac monopole on the 2-sphere $S^2$, of a graded monopole on a (2,2)-supersphere $S^{2,2}$ and of the BPST instanton on the 4-sphere $S^4$, by constructing a suitable global projector $p$ via equivariant maps. This projector determines the projective module of finite type of sections of the corresponding vector bundle. The canonical connection $\nabla = p \circ d$ is used to compute the topological charge which is found to be equal to -1 for the three cases. The transposed projector $q=p^t$ gives the value +1 for the charges; this showing that transposition of projectors, although an isomorphism in $K$-theory, is not the identity map. We also study the invariance under the action of suitable Lie groups.
Projective Modules of Finite Type over the Supersphere $S^{2,2}$
Giovanni Landi
Physics , 1999,
Abstract: In the spirit of noncommutative geometry we construct all inequivalent vector bundles over the $(2,2)$-dimensional supersphere $S^{2,2}$ by means of global projectors $p$ via equivariant maps. Each projector determines the projective module of finite type of sections of the corresponding `rank 1' supervector bundle over $S^{2,2}$. The canonical connection $\nabla = p \circ d$ is used to compute the Chern numbers by means of the Berezin integral on $S^{2,2}$. The associated connection 1-forms are graded extensions of monopoles with not trivial topological charge. Supertransposed projectors gives opposite values for the charges. We also comment on the $K$-theory of $S^{2,2}$.
Projective Modules of Finite Type and Monopoles over $S^2$
Giovanni Landi
Physics , 1999, DOI: 10.1016/S0393-0440(00)00032-2
Abstract: We give a unifying description of all inequivalent vector bundles over the 2-dimensional sphere $S^2$ by constructing suitable global projectors $p$ via equivariant maps. Each projector determines the projective module of finite type of sections of the corresponding complex rank 1 vector bundle over $S^2$. The canonical connection $\nabla = p \circ d$ is used to compute the topological charges. Transposed projectors gives opposite values for the charges, thus showing that transposition of projectors, although an isomorphism in K-theory, is not the identity map. Also, we construct the partial isometry yielding the equivalence between the tangent projector (which is trivial in K-theory) and the real form of the charge 2 projector.
Eigenvalues as Dynamical Variables
Giovanni Landi
Physics , 1999,
Abstract: We review some work done with C. Rovelli on the use of the eigenvalues of the Dirac operator on a curved spacetime as dynamical variables, the main motivation coming from their invariance under the action of diffeomorphisms. The eigenvalues constitute an infinite set of ``observables'' for general relativity and can be taken as variables for an invariant description of the gravitational field dynamics.
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