6,854 research outputs found
Signorie e comunità rurali nel Vercellese fra crisi del districtus cittadino e nascita dello stato principesco
No full textLa dipendenza politica del marchesato di Saluzzo nei confronti delle potenze vicine al tempo di Ludovico I
No full textA new three-steps iterative method for solving nonlinear systems
No full textCapdevila, RR.; Cordero Barbero, A.; Torregrosa Sánchez, JR. (2019). A new three-steps iterative method for solving nonlinear systems. R. Company, J. C. Cortés, L. Jódar and E.López-Navarro. 22-25. https://riunet.upv.es/handle/10251/180675S222
Barbero--Immirzi--Holst Lagrangian with Spacetime Barbero--Immirzi Connections
No full textWe carry out the complete variational analysis of the Barbero--Immirzi--Holst
Lagrangian, which is the Holst Lagrangian expressed in terms of the triad of
fields , where is the solder form/spin frame,
is the spacetime Barbero--Immirzi connection, and is the extrinsic
spacetime field. The Holst Lagrangian depends on the choice of a real, non zero
Holst parameter and constitutes the classical field theory
which is then quantized in Loop Quantum Gravity. The choice of a real Immirzi
parameter sets up a one-to-one correspondence between pairs and spin connections on spacetime. The variation of the
Barbero--Immirzi--Holst Lagrangian is computed for an arbitrary pair of
parameters . We develop and use the calculus of vector-valued
differential forms to improve on the results already present in literature by
better clarifying the geometric character of the resulting Euler--Lagrange
equations. The main result is that the equations for are equivalent to
the vacuum Einstein Field Equations, while the equations for and
give the same constraint equation for any , namely that
must be the Levi--Civita connection induced by . We also
prove that these results are valid for any value of , meaning
that the choice of parameters has no impact on the classical
theory in a vacuum and, in particular, there is no need to set .Comment: 43 pages, 0 figure
Critical thickness of a hybrid aligned nematic liquid crystal cell
No full textWe discuss the director deformation inside a hybrid aligned nematic (HAN) cell, assuming that the surface interaction is of the (w/2) sin2 (φ - Φ) kind, and we suppose that the anchoring energy for homeotropic alignment is greater than the planar one. In the absence of an external electric field, we show that a critical thickness dc, below which the nematic liquid crystal (NLC) is undistorted, exists. Furthermore we investigate theoretically dc vs. the reduced electric field (E/Ec, where Ec is a threshold field depending upon the anchoring energies and the intrinsic constants of the NLC). The last analysis shows that there are two critical thicknesses dc(H) and dc(P): for d < dc(H) the sample is homeotropic (HOM), while for d > dc(P) it is planar (PLAN). Finally we point out that if the anchoring energies are the same on the upper and lower plates of the sample, the HAN-configuration is realizable only if E/Ec < 1
Domenico Barbero e le universalità patrimoniali
No full textIl saggio costituisce una rilettura della monografia di Domenico Barbero sulle universalità patrimoniali. Si tratta di un “classico” del diritto che, come tale, conserva un significato attuale in relazione al metodo seguito dall’autore e alle soluzioni giuridiche in essa proposte.
Sotto il primo profilo l’autore avverte che lo studio del diritto non può appiattirsi nella «prospettiva analitica», ma deve cogliere anche la «dimensione empirica» della scienza giuridica. In questo senso il metodo argomentativo di Barbero, pur presentando elementi propri del formalismo concettuale, non prescinde dal confronto costruttivo con la realtà. Da tale prospettiva Barbero ricostruisce l’universalità di beni come categoria unitaria non dal punto di vista ontologico, ma logico, osservando che essa rimane identica pur quando cambino le cose che ontologicamente ne costituiscono parte integrante.
Altro aspetto di modernità dell’opera di Barbero è il convincimento che le norme giuridiche sono frutto di precise scelte politiche e non già mera sovrastruttura di fenomeni economici. L’impostazione positivistica di Barbero non domina tuttavia incontrastata, ma è controbilanciata dalla consapevolezza che la regola applicata, lungi dal risolversi in una manifestazione arbitraria di volontà del legislatore, debba essere espressione della naturale razionalità del diritto.Universality of Assets
The essay revisits Domenico Barbero's monograph on universality of assests . It is a "classic" of law, which, as such, retains a contemporary relevance both in relation to the method followed by the author and the legal solutions proposed in it.
Regarding the first aspect, the author notes that the study of law cannot be reduced to an "analytical perspective," but must also capture the "empirical dimension" of legal science. In this sense, Barbero's argumentative method, while presenting elements typical of conceptual formalism, does not disregard a constructive dialogue with reality. On this basis, Barbero reconstructs the universality of assets as a unified category, not from an ontological point of view but a logical one, observing that it remains identical even when the individual things change.
Another modern aspect of Barbero's work is the conviction that legal rules are the result of precise political choices and not merely a superstructure of economic phenomena. However, Barbero's positivist approach does not prevail unchallenged, but is counterbalanced by the awareness that the applied rule, far from being an arbitrary manifestation of the legislator's will, must be an expression of the natural rationality of law
The structure of the distortion free-energy density in nematics: second-order elasticity and surface terms
No full textA low percentage of autologous serum can replace bovine serum to engineer human nasal cartilage
No full textFor the generation of cell-based therapeutic products, it would be preferable to avoid the use of animal-derived components. Our study thus aimed at investigating the possibility to replace foetal bovine serum (FBS) with autologous serum (AS) for the engineering of cartilage grafts using expanded human nasal chondrocytes (HNC). HNC isolated from 7 donors were expanded in medium containing 10 concentrations (2 serum-free medium or in Hyaff (R)-11 meshes using medium containing FBS or AS. Tissue forming capacity was assessed histologically (Safranin O), immunohistochemically (type II collagen) and biochemically (glycosaminoglycans - GAG- and DNA). Differences among experimental groups were assessed by Mann Whitney tests. HNC expanded under the different serum conditions proliferated at comparable rates and generated cartilaginous pellets with similar histological appearance and amounts of GAG. Tissues generated by HNC from different donors cultured in Hyaff (R)-11 had variable quality, but the accumulated GAG amounts were comparable among the different serum conditions. Staining intensity for collagen type II was consistent with GAG deposition. Among the different serum conditions tested, the use of 2 in the lowest variability in the GAG contents of generated tissues. In conclusion, a low percentage of AS can replace FBS both during the expansion and differentiation of HNC and reduce the variability in the quality of the resulting engineered cartilage tissues
Influence of ply cluster thickness and location on matrix cracking evolution in open-hole composite laminates
No full textThe influence of cluster thickness and its position on the damage evolution of open-hole composite laminates, subjected to uniaxial in-plane tensile loads, is studied in this work. The Discrete Damage Mechanics model of Barbero-Cortes augmented by a fiber damage criterion is employed. Several stacking sequences with clusters in different positions and thicknesses inside the laminate are analyzed. The influence of cluster thickness and its location on: the crack-density evolution, applied load, longitudinal stress and its contour plots is studied for all the stacking sequences selected.The authors are indebted for the financial support of this work
to the Ministry of Economy and Competitiveness (grant number
DPI2013 42240 R)
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