7,474 research outputs found
Between Two Empires. Histoire des deux Indes And Modern Colonialism
No full textThe article critically analyses the late eighteenth century process of crisis and transformation of the concept of empire. By considering Raynal’s Histoire des deux Indes and the Enlightenment’s critique of the different imperial models, Pandolfi reconstructs the transit from classic colonialism – built around the relations between settlers, savages and slaves – to another phase characterized by the indirect exploitation of the labour force. The text underlines the ambivalence of Enlightenment towards the question of the empire by demonstrating how Raynal’s work reflects the constitutive tension of the second half of the 1700s. Therefore, through Diderot’s analysis, the author demonstrates how the moral advancement of humanity is the product of a constant interaction between the colonial rhetoric of commerce and those revolutions, which, – in different moments and places – have crossed the colonial space
Diffusion-based degeneration of the collagen reinforcement in the pathologic human cornea
No full textWe describe a multiphysics model of the collagen structure of the cornea undergoing a progressive localized reduction of the stiffness, preluding to the development of ectasia and keratoconus. The architecture of the stromal collagen is assumed to follow the simplified two-family model proposed in Pandolfi et al. (A microstructural model of cross-link interaction between collagen fibrils in the human cornea. Philos Trans R Soc A 377:20180079, 2019), where the mechanical stiffness of the structure is supplied by transversal bonds within the fibrils of the same family (inter-crosslink bonds) and across the fibrils of the two families (intra-crosslink bonds). In Pandolfi et al. (A microstructural model of cross-link interaction between collagen fibrils in the human cornea. Philos Trans R Soc A 377:20180079, 2019), it was shown that the loss of the spherical shape due to the protrusion of a cone can be ascribed to the mechanical weakening of the intra-crosslink bonds in the central region of the collagen structure. In the present study, the reduction of bond stiffness is coupled to an evolutive pathologic phenomenon, modeled as a reaction–diffusion process of a normalized scalar field. We assume that the scalar field is a concentration-like measure of the degeneration of the chemical bonds stabilizing the structural collagen. We follow the evolution of the mechanical response of the system in terms of shape change, according to the propagation of the degeneration field, and identify the critical loss of mechanical stability resulting in the typical bulging of keratoconus corneas
A predictive model of UV-A-riboflavin crosslinking treatment on porcine corneas
No full textThe crosslinking technique (CXL) is an effective low-risk
therapeutic treatment of keratoconus and other
ectatic disorders of the human cornea. The effect
of corneal CXL is to increase the stiffness of the
stroma to prevent the progression of the cornea
distortion. Several clinical and experimental studies
have shown that the stiffening effects predominantly
localise on the anterior portion of the stroma and
that the in-depth stiffening distribution is highly
dependent on the duration of treatment. Yet, how
the stiffening effects distribute through the cornea
thickness as a function of the treatment duration is
an open question. Here we propose an analytical
model of the stiffening profile due to CXL-treatment
as a function of the irradiation time. We consider
linear and nonlinear variations of the crosslinking
effects across the thickness and implement them into
a finite element model of the porcine cornea. We
present a time-dependent in-depth stiffening profile
that allows us to predict the post-operative corneas
response to physiological intraocular pressure for
different irradiation times. We anticipate that this
predictive model will support the development of
patient specific 3D models that will allow clinicians
to design customised CXL treatment, thus enhancing
treatment outcomes
Applications of a micro-structured brittle damage model to laboratory tests on rocks
No full textA multiscale microstructured brittle damage model is used to describe the behavior of confined rock materials. Plane strain and triaxial tests conducted
at the laboratory scale are simulated in terms of boundary value problems. Simulations reveal good predictive qualities of the model to describe the macroscopic features of specimens at failure. The microstructures, oriented in different directions, allow the localization of the macroscopic strain along straight lines, emerging at the macroscale in the form of shear bands. The microstructured material model, characterized by recursive equidistant parallel cohesive-frictional faults, is fully defined by six elastic and inelastic material constants. The model was originally developed in a finite kinematics framework to simulate the dynamic behavior of confined brittle materials (Pandolfi et al. in J
Mech Phys Solids 54:1972–2003, 2006). In linearized form, it has been extended and used for the simulation of in-field excavations (De Bellis et al. in: Eng
Geol 215:10–24, 2016). The performance of the model in predicting the behavior of small scale rock tests in the laboratory, the object of the present study, has
never been investigated. Numerical simulations show that the model is able to capture several important features observed in rocks, in particular the reduction
of the overall stiffness for increasing deterioration of the material, fragile to ductile transition, strain localization, shear band formation, and more general size effect
Persiatherium Pandolfi 2016
No full textGenus <i>Persiatherium</i> Pandolfi, 2016 <p> TYPE SPECIES. — <i>Persiatherium rodleri</i> Pandolfi, 2016 by original designation (Pandolfi 2016: 2).</p>Published as part of <i>Antoine, Pierre-Olivier & Sen, Sevket, 2016, Rhinocerotidae and Chalicotheriidae (Perissodactyla, Tapiromorpha), pp. 245-259 in Geodiversitas 38 (2)</i> on page 253, DOI: 10.5252/g2016n2a6, <a href="http://zenodo.org/record/5207918">http://zenodo.org/record/5207918</a>
Américo Ghioldi en Radio Universidad : Una entrevista de Rodolfo Pandolfi en su programa Interrogatorio
No full textEl dirigente del Partido Socialista Auténtico Américo Ghioldi responde a una entrevista de Rodolfo Pandolfi en su programa Interrogatorio. Se refieren a su formación y trayectoria, a su mirada sobre los partidos políticos argentinos y es particular al socialismo en el siglo XX.
Américo Ghioldi: nació el 23 de mayo de 1899 en Buenos Aires y murió en 1984. Fue docente y dirigente socialista. Fue convencional constituyente, diputado nacional y embajador durante la última dictadura.Radio Universidad Nacional de La Plat
Américo Ghioldi en Radio Universidad : Una entrevista de Rodolfo Pandolfi en su programa Interrogatorio
No full textEl dirigente del Partido Socialista Auténtico Américo Ghioldi responde a una entrevista de Rodolfo Pandolfi en su programa Interrogatorio. Se refieren a su formación y trayectoria, a su mirada sobre los partidos políticos argentinos y es particular al socialismo en el siglo XX.
Américo Ghioldi: nació el 23 de mayo de 1899 en Buenos Aires y murió en 1984. Fue docente y dirigente socialista. Fue convencional constituyente, diputado nacional y embajador durante la última dictadura.Radio Universidad Nacional de La Plat
Seep carbonates and chemosynthetic coral communities in the Bocco Shale (Internal Ligurides, Northern Apennine, Italy) as record of trench-slope limit in the Early Paleocene alpine accretionary wedge
No full textIn Northern Apennines, the Internal Liguride units are characterized by an ophiolite sequence that represents the stratigraphic base of a Late Jurassic-Early Paleocene sedimentary cover. The Bocco Shale represents the youngest deposit recognized in the sedimentary cover of the ophiolite sequence, sedimented just before the inception of subduction-related deformation history.
The Bocco Shale has been interpreted as a fossil example of deposits related to the frontal tectonic erosion of the alpine accretionary wedge slope. The frontal tectonic erosion resulted in a large removal of material from the accretionary wedge front reworked as debris flows and slide deposits sedimented on the lower plate above the trench deposits. These trench-slope deposits may have been successively deformed and metamorphosed during the following accretion processes.
The frontal tectonic erosion can be envisaged as a common process during the convergence-related evolution of the Ligure-Piemontese oceanic basin in the Late Cretaceous-Early Tertiary time span.
In the uppermost Internal Liguride tectonic unit (Portello Unit of Pandolfi and Marroni. 1997), that crops-out in Trebbia Valley, several isolated blocks of authigenic carbonates, unidentificated corals and intrabasinal carbonatic arenites have been recognized inside the fine-grained sediments that dominate the Early Paleocene Lavagnola Fm. (cfr. Bocco Shale Auctt.).
The preliminary data on stable isotopes from blocks of authigenic carbonates (up to 1 m thick and 3 m across) and associated corals archive a methane signatures in their depleted carbon isotope pattern (up to δ13C –30‰ PDB) and suggest the presence of chemosynthetic paleocommunities.
The seep-carbonates recognized at the top of Internal Liguride succession (cfr. Bocco Shale Auctt.) occur predominantly as blocks in very thick mudstone-dominated deposits and probably developed in an environment dominated by the expulsion of large volume of cold methane-bearing fluids focused in the frontal part of the Early Paleocene alpine accretionary wedge
Storia delle due Indie
No full textIl testo offre per la prima volta ai lettori e agli studiosi italiani una vasta antologia dell’Histoire philosophique et politique des établissements et du commerce des Européens dans les deux Indes. Il volume antologizza criticamente numerosi capitoli della terza edizione pubblicata a Ginevra nel 1780. Il libro dell’abate Raynal è un’opera di importanza capitale nella storia dell’Illuminismo. Si tratta della prima storia organica del colonialismo e dell’imperialismo europeo dall’incursione dei Portoghesi nell’Oceano indiano alla fine del XV secolo alla Rivoluzione americana.
L’Histoire des deux Indes, frutto di un lavoro di gruppo coordinato da Raynal, insieme all’Enclyclopedie costituisce la summa della cultura illuminista. All’opera collaborarono Saint Lambert, Jussieu, Deleyre, Pechméja, forse il marchese d’Holbach e sicuramente Diderot il cui contributo all’Histoire (circa 500 pagine) è il nucleo più corposo dell’intera opera del filosofo. L’Histoire, testo sterminato, straordinariamente ricco di argomenti e problematiche di ogni genere, è stata letta in Europa, in Asia e nelle Americhe come un manifesto dell’anticolonialismo e la prima requisitoria filosofica e politica contro il sistema della schiavitù
A Numerical Study of Arterial Media Dissection Processes
No full textIn medical terms and referring to aortic arterial damage, dissection is the separation of intra-medial tissue induced by a radial tear cutting the intima (inner layer) and a portion of the underling media (middle layer). Pressurized blood pervading the tear enhances the intramural process of dissection, and may induce a subsequent formation of clots. The purpose of this study is to setup and calibrate a numerical model of arterial dissection, based on cohesive theories of fracture. The dissection model is used to characterize the critical mechanical conditions for the interlamellar propagation of a tear in the media and the influence of the reinforcing collagen fibers on the separation process
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