Search results for "Roca"
showing 10 items of 1893 documents
Francisco Vergara y la Academia de San Lucas de Roma
1994
MIEMBRO DE UNA DESTACADA FAMILIA DE ARTISTAS, FRANCISCO VERGARA BARTUAL (C. 1716-1761) RECIBIO SU PRIMERA FORMACION EN EL TALLER PATERNO. CUANDO HUBO COMPLETADO SU APRENDIZAJE A LOS 17 AÑOS, INGRESO DE PLENO DERECHO EN EL GREMIO DE CARPINTEROS DE VALENCIA. LOS DESEOS DE COMPLETAR SUS ENSEÑANZAS DEBIERON IMPULSARLE A MARCHAR PRIMERO A LA CORTE, ATRAIDO POR LAS OBRAS DEL PALACIO REAL, Y LUEGO A ITALIA. EN ROMA CONOCIO LA MAS MODERNA ESCULTURA DEL SETECIENTOS, MUY INFLUIDA AUN POR BERNINI, ALGARDI Y DUQUESNOY. APOYADO POR FILIPPO DELLA VALLE, EL MAS CARISMATICO ESCULTOR EN LA ROMA DE MITAD DEL SIGLO, INGRESO EN LA ACADEMIA DE SAN LUCAS Y EN LA DE DESNUDO DEL CAPITOLIO. EN LA CIUDAD ETERNA LLEV…
Experimental and Numerical Analysis of Microstructure Evolution during Linear Friction Welding of Ti6Al4V
2015
Abstract Linear Friction Welding (LFW) is a solid state welding process used to joint bulk components. In the paper, an experimental and numerical study on LFW of Ti6Al4V titanium alloy is presented. A laboratory designed LFW machine has been used to weld the specimens with different contact pressure and oscillation frequency. The joint microstructure has been experimentally observed with SEM and EDS. A dedicated numerical model, able to predict temperature, strain and strain rate distribution as well as the phase volume fraction evolution, has been utilized to predict the final microstructure in the welded parts. It was found that complete transformation of the alpha phase into beta phase …
Numerical modelling of the linear friction welding process
2010
Linear friction welding (LFW) is a solid-state joining process applied to non-axisymmetric components. LFW involves joining of materials through the relative reciprocating motion of two components under an axial force. In such process the heat source is given by the frictional forces work decaying into heat determining a local softening of the material and proper bonding conditions due to both the temperature increase and the local pressure of the two edges to be welded. In the present work the authors present a numerical model of the linear friction welding process of AISI 1045 parts. The numerical model allowed to highlight the process mechanics and the physical conditions which must be r…
Microreflectivity studies of wavelength control in oxidised AlGaAs microcavities
2003
Wet oxidation of GaAs/AlGaAs structures is an important technique in the processing of advanced devices such as vertical cavity surface emitting lasers (VCSELs). In one VCSEL application, the low-index and electrically-insulating AlxOy layers have been used to obtain high-reflectivity and broad bandwidth distributed Bragg reflector mirrors (DBRs). A further recent development has shown that combined lateral–vertical oxidation of intracavity AlGaAs layers can be used to tune the resonant wavelength of a semiconductor microcavity. The slow oxidation rate limits the lateral scale of practical wet oxidation to mesas structures of 50–100 μm in width. Therefore post-processing assessment of spect…
CESAR: Cryogenic Electronics for Space Applications
2013
Ultra-low temperature sensors provide unprecedented performances in X-ray and far infrared astronomy by taking advantage of physical properties of matter close to absolute zero. CESAR is an FP7 funded project started in December 2010, that gathers six European laboratories around the development of high performances cryogenic electronics. The goal of the project is to provide far-IR, X-ray and magnetic sensors with signal-processing capabilities at the heart of the detectors. We present the major steps that constitute the CESAR work, and the main results achieved so far.
Genetic study of the production of sexually dimorphic cuticular hydrocarbons in relation with the sex-determination gene transformer in Drosophila me…
2002
In Drosophila melanogaster, the main cuticular hydrocarbons (HCs) are some of the pheromones involved in mate discrimination. These are sexually dimorphic in both their occurrence and their effects. The production of predominant HCs has been measured in male and female progeny of 220 PGal4 lines mated with the feminising UAS-transformer transgenic strain. In 45 lines, XY flies were substantially or totally feminised for their HCs. Surprisingly, XX flies of 14 strains were partially masculinised. Several of the PGal4 enhancer-trap variants screened here seem to interact with sex determination mechanisms involved in the control of sexually dimorphic characters. We also found a good relationsh…
Regulation of cuticular hydrocarbon profile maturation by Drosophila tanning hormone, bursicon, and its interaction with desaturase activity
2016
International audience; Shortly after emergence the exoskeleton (cuticle) of adult insects is rapidly expanded, hardened (sclerotized), and pigmented (melanized). In parallel with this process, the oenocytes, which are large polyploid cells located below the abdominal epidermis, secrete onto the cuticle a cocktail of cuticular hydrocarbons (CHs) and waxes. These improve the waterproofing of the cuticle, and also provide important chemosensory and pheromonal cues linked with gender, age, and species differentiation. The hardening and pigmentation of the new cuticle are controlled by the neurohormone, bursicon, and its receptor, encoded by the DLGR2 receptor, rickets (rk); by contrast, little…
Dietary rescue of altered metabolism gene reveals unexpected [i]Drosophila[/i] mating cues
2015
Running title: Dietary rescue of metabolic mutation and reproduction; To develop and reproduce, animals need long-chain Mono and PolyUnsaturated Fatty Acids (MUFAs; PUFAs). Although some UFAs can be synthesized by the organism, others must be provided by the diet. The gene desat1, involved in Drosophila melanogaster UFA metabolism, is necessary for both larval development and for adult sex pheromone communication. We first characterized desat1 expression in larval tissues. Then, we found that larvae in which desat1 expression was knocked down throughout development died during the larval stages when raised on standard food. By contrast pure MUFAs or PUFAs, but not saturated FAs, added to th…
A Mutation With Major Effects on Drosophila melanogaster Sex Pheromones
2005
0016-6731 (Print) Comparative Study Journal Article Research Support, Non-U.S. Gov't; Sex pheromones are intraspecific chemical signals that are crucial for mate attraction and discrimination. In Drosophila melanogaster, the predominant hydrocarbons on the cuticle of mature female and male flies are radically different and tend to stimulate or inhibit male courtship, respectively. This sexual difference depends largely upon the number of double bonds (one in males and two in females) added by desaturase enzymes. A mutation was caused by a PGal4 transposon inserted in the desat1 gene that codes for the desaturase crucial for setting these double bonds. Homozygous mutant flies produced 70-90%…
The consequences of regulation of desat1 expression for pheromone emission and detection in Drosophila melanogaster.
2010
AbstractSensory communication depends on the precise matching between the emission and the perception of sex- and species-specific signals; understanding both the coevolutionary process and the genes involved in both production and detection is a major challenge. desat1 determines both aspects of communication—a mutation in desat1 simultaneously alters both sex pheromone emission and perception in Drosophila melanogaster flies. We investigated whether the alteration of pheromonal perception is a consequence of the altered production of pheromones or if the two phenotypes are independently controlled by the same locus. Using several genetic tools, we were able to separately manipulate the tw…