809 research outputs found
La figura della rana all’interno della popolazione precolombiana dei Muisca: iconografia e simbolismo
In Colombia gli anfibi rivestirono un ruolo privilegiato nel mondo simbolico degli indigeni preispanici, visto il gran numero di rappresentazioni riscontrabili a livello archeologico. Vengono qui presentati i risultati di un'analisi dettagliata dei moduli iconografici di rappresentazione e del sistema simbolico associati alla figura della rana nell'ambito della cultura Muisca, la popolazione precolombiana attestata nell'Altiplano Cundiboyacense dal 600 d.C. al 1600 d.C., sulla scorta dello studio delle evidenze materiali. Questo anfibio, lungi dall’essere associato esclusivamente con il ciclo della natura e della fertilità in agricoltura, è espressione di un sistema simbolico ben più complesso ed articolato
Debonding of adhesive joints by means of microwave and induction heating processes
In this work, an innovative technique for adhesive joint separation that combines the use of a hybrid-modified adhesive with microwave (MW) or induction heating (IH) [1-3] processes is presented. Graphene nanoplatelets (GnPs) and iron oxide particles were used to modify a thermoplastic adhesive, polyolefin hot-melt adhesive by mean of a twin-screw extruder. This thermoplastic adhesive, already used for bonding automotive applications, was modified with both iron oxide and GnPs in order to enhance the electrical properties and the sensitivity to MW and IH. The mechanical and electrical properties together with the sensitivity of the modified adhesives to microwave or induction heating processes are investigated. Single Lap Joint (SLJ) specimens were used to evaluate the mechanical properties of the pristine and the modified adhesive. The mechanical tests illustrate that the maximum loads of modified adhesives decrease slightly. Tests conducted with microwave and induction heating processes showed that these two systems are able to melt the modified adhesive. Thus, the separation of bonded joints is possible with both systems. The temperature increase of the induction heating system is found to be more rapid than the microwaves but the latter system is energetically more efficient. Scanning Electron Microscope (SEM) was used to measure the particle distribution and to evaluate the differences between the manual mixed mode and the tween extruder system as preliminary analysis
On the structure of codimension 1 foliations with pseudoeffective conormal bundle.
International audienceLet a projective manifold equipped with a codimension (maybe singular) distribution whose conormal sheaf is assumed to be pseudoeffective. By a theorem of Jean-Pierre Demailly, this distribution is actually integrable and thus defines a codimension holomorphic foliation \F. We aim at describing the structure of such a foliation, especially in the non abundant case: It turns out that \F is the pull-back of one of the "canonical foliations" on a Hilbert modular variety. This result remains valid for ''logarithmic foliated pairs''
Ofd1 Controls Dorso-Ventral Patterning and Axoneme Elongation during Embryonic Brain Development.
Oral-facial-digital type I syndrome (OFDI) is a human X-linked dominant-male-lethal developmental disorder caused by mutations in the OFD1 gene. Similar to other inherited disorders associated to ciliary dysfunction OFD type I patients display neurological abnormalities. We characterized the neuronal phenotype that results from Ofd1 inactivation in early phases of mouse embryonic development and at post-natal stages. We determined that Ofd1 plays a crucial role in forebrain development, and in particular, in the control of dorso-ventral patterning and early corticogenesis. We observed abnormal activation of Sonic hedgehog (Shh), a major pathway modulating brain development. Ultrastructural studies demonstrated that early Ofd1 inactivation results in the absence of ciliary axonemes despite the presence of mature basal bodies that are correctly orientated and docked. Ofd1 inducible-mediated inactivation at birth does not affect ciliogenesis in the cortex, suggesting a developmental stage-dependent role for a basal body protein in ciliogenesis. Moreover, we showed defects in cytoskeletal organization and apical-basal polarity in Ofd1 mutant embryos, most likely due to lack of ciliary axonemes. Thus, the present study identifies Ofd1 as a developmental disease gene that is critical for forebrain development and ciliogenesis in embryonic life, and indicates that Ofd1 functions after docking and before elaboration of the axoneme in vivo
On the interactions of melatonin/β-cyclodextrin inclusion complex: A novel approach combining efficient semiempirical extended tight-binding (xtb) results with ab initio methods
Melatonin (MT) is a molecule of paramount importance in all living organisms, due to its presence in many biological activities, such as circadian (sleep–wake cycle) and seasonal rhythms (reproduction, fattening, molting, etc.). Unfortunately, it suffers from poor solubility and, to be used as a drug, an appropriate transport vehicle has to be developed, in order to optimize its release in the human tissues. As a possible drug-delivery system, β-cyclodextrin (βCD) represents a promising scaffold which can encapsulate the melatonin, releasing when needed. In this work, we present a computational study supported by experimental IR spectra on inclusion MT/βCD complexes. The aim is to provide a robust, accurate and, at the same time, low-cost methodology to investigate these inclusion complexes both with static and dynamic simulations, in order to study the main actors that drive the interactions of melatonin with β-cyclodextrin and, therefore, to understand its release mechanism
Active strain-rate Across the Messina Straits and Kinematics of Sicily and Calabria From GPS Data
The Messina Straits is the locus of one of the strongest seismic event that ever hit Italy during historical times,
the 1908 Mw 7.1 earthquake, and the same region also suffered major damage from other strong earthquakes
in the last few centuries. However, despite the large amount of data and studies carried out, our knowledge of
the present-day deformation of this area is still debated. While a general consensus has been reached about the
kinematics of the 1908 causative fault, less is known about the rate and shape of interseismic loading across the
Straits, and debate continues also about the general kinematics and geodynamic framework of this region which
are strongly influenced by subduction and retreat of Ionian lithosphere. Thanks to the increasing number of GPS
Networks in the study region it is now possible to study both the regional kinematics and strain loading across
active faults. In this work we analyze all the observations collected over the Messina non-permanent GPS Network
for the 1994-2008 time span, and data from about 600 CGPS stations in the Euro-Mediterranean region, using the
GAMIT software.
The output of our analysis is a new and denser velocity field, which is used to study the plate kinematics and the
rate of interseismic strain building across the Straits. GPS velocities show a sudden change in their orientation
across the Straits moving to NNW-ward, in Estern Sicily, to NNE-ward in Western Calabria, depicting this area as
a primary boundary between two different tectonic domains.
The maximum strain-rates observed across the Straits are about 120 nanostrain/yr, with extension oriented about
normal to the coasts of Sicily according to the presence of a normal fault. The measured velocity gradient can
be used to model the creeping dislocation at depth, however, over the Messina Straits the interseismic elastic
strains accumulating across other nearby active faults can significantly affect the observed velocity gradient.For
this reason we investigate, using a regional elastic block-modeling approach, these effects. We use the block model
to test for different microplates configurations and to account for nearby active faults while inverting for optimal
fault geometry and intersismic slip-rates across the Straits
On the interactions of melatonin/β-cyclodextrin inclusion complex: A novel approach combining efficient semiempirical extended tight-binding (xtb) results with ab initio methods
Melatonin (MT) is a molecule of paramount importance in all living organisms, due to its presence in many biological activities, such as circadian (sleep–wake cycle) and seasonal rhythms (reproduction, fattening, molting, etc.). Unfortunately, it suffers from poor solubility and, to be used as a drug, an appropriate transport vehicle has to be developed, in order to optimize its release in the human tissues. As a possible drug-delivery system, β-cyclodextrin (βCD) represents a promising scaffold which can encapsulate the melatonin, releasing when needed. In this work, we present a computational study supported by experimental IR spectra on inclusion MT/βCD complexes. The aim is to provide a robust, accurate and, at the same time, low-cost methodology to investigate these inclusion complexes both with static and dynamic simulations, in order to study the main actors that drive the interactions of melatonin with β-cyclodextrin and, therefore, to understand its release mechanism
Sur le lemme de Brody
Brody's lemma is a basic tool in complex hyperbolicity. We present a version
of it making more precise the localization of an entire curve coming from a
diverging sequence of holomorphic discs. As a byproduct we characterize
hyperbolicity in terms of an isoperimetric inequality
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