425 resultados para 1141


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Estudiar el tema de la adquisición del esquema corporal en el niño. Ejercicios (tablas). Se puede suponer que al realizar los niños estos ejercicios se desarrollan aspectos del equilibrio y esquema corporal. Se afirma que es fundamental en la etapa de formación de edad preescolar con carácter lúdico. Es importante crear un clima afectivo para así obtener unos resultados positivos.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

El test de circuits és una fase del procés de producció que cada vegada pren més importància quan es desenvolupa un nou producte. Les tècniques de test i diagnosi per a circuits digitals han estat desenvolupades i automatitzades amb èxit, mentre que aquest no és encara el cas dels circuits analògics. D'entre tots els mètodes proposats per diagnosticar circuits analògics els més utilitzats són els diccionaris de falles. En aquesta tesi se'n descriuen alguns, tot analitzant-ne els seus avantatges i inconvenients. Durant aquests últims anys, les tècniques d'Intel·ligència Artificial han esdevingut un dels camps de recerca més importants per a la diagnosi de falles. Aquesta tesi desenvolupa dues d'aquestes tècniques per tal de cobrir algunes de les mancances que presenten els diccionaris de falles. La primera proposta es basa en construir un sistema fuzzy com a eina per identificar. Els resultats obtinguts son força bons, ja que s'aconsegueix localitzar la falla en un elevat tant percent dels casos. Per altra banda, el percentatge d'encerts no és prou bo quan a més a més s'intenta esbrinar la desviació. Com que els diccionaris de falles es poden veure com una aproximació simplificada al Raonament Basat en Casos (CBR), la segona proposta fa una extensió dels diccionaris de falles cap a un sistema CBR. El propòsit no és donar una solució general del problema sinó contribuir amb una nova metodologia. Aquesta consisteix en millorar la diagnosis dels diccionaris de falles mitjançant l'addició i l'adaptació dels nous casos per tal d'esdevenir un sistema de Raonament Basat en Casos. Es descriu l'estructura de la base de casos així com les tasques d'extracció, de reutilització, de revisió i de retenció, fent èmfasi al procés d'aprenentatge. En el transcurs del text s'utilitzen diversos circuits per mostrar exemples dels mètodes de test descrits, però en particular el filtre biquadràtic és l'utilitzat per provar les metodologies plantejades, ja que és un dels benchmarks proposats en el context dels circuits analògics. Les falles considerades son paramètriques, permanents, independents i simples, encara que la metodologia pot ser fàcilment extrapolable per a la diagnosi de falles múltiples i catastròfiques. El mètode es centra en el test dels components passius, encara que també es podria extendre per a falles en els actius.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This study examines whether background noise, presented at 10 dB below its reflex threshold, affects the acoustic reflex (AR) response for pure tones presented subsequent to the onset of the noise.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Esta tesis se propone explorar la representación de la memoria histórica en el cine latinoamericano. Para ello, establece un diálogo entre dos momentos de la historia del cine regional: el Nuevo Cine Latinoamericano de los años 60, erigido en movimiento cinematográfico con características peculiares, y el cine latinoamericano producido en el umbral del siglo XXI. Y lo hace a partir de la exploración de ciertas características comunes en cuanto a los temas, las formas narrativas, el modo de producción, pero muy especialmente a partir de la preocupación compartida por la representación de la memoria histórica de las grandes mayorías, tanto como de los grupos sociales minoritarios, cuyas voces han sido excluidas de la historiografía tradicional –vale decir, la “historia oficial- escrita por las elites que han gobernado los países latinoamericanos desde su constitución como repúblicas. Es propósito de esta tesis mostrar que en América Latina el desarrollo de los movimientos cinematográficos de ruptura se ha dado en estrecha vinculación con las conflictivas circunstancias económicas, sociales y políticas de diferentes momentos históricos, y la forma en que estos movimientos han contribuido a la identidad del cine latinoamericano. El primer capítulo constituye un recorrido por el movimiento del Nuevo Cine Latinoamericano de los años 60, sus películas y principales postulados estéticos y políticos, y la forma en que este movimiento, al colocar en el centro temas enteramente nuevos como la representación de la memoria colectiva de los excluidos, provoca una ruptura con el cine producido hasta ese entonces en la región y un giro en la identidad que tomara la producción cinematográfica regional a partir de entonces. En el segundo capítulo, se analiza la representación de la memoria colectiva de la Crisis Bancaria de 1999 en Ecuador hecha por la película nacional “Fuera de Juego” y la forma en que esta representación, constituida muchas veces como contraanálisis de la interpretación que de aquel suceso dieron los medios de información, dialoga con los postulados del Nuevo Cine Latinoamericano. El tercer y último capítulo está a dedicado a otros dos estudios de caso sobre la representación de la memoria histórica en el cine latinoamericano de finales de los años 90. Se trata de la cinta colombiana “La Vendedora de Rosas” y la argentina “Pizza, Birra, Faso”, cuya narración, aunque apelando a muy diferentes estrategias estéticas y narrativas, coincide con “Fuera de Juego” en cuanto a la necesidad de poner sobre el tapete la memoria colectiva sobre el despojo operado por la aplicación de las políticas neoliberales en América Latina durante los 90, y, por lo tanto, dialoga con las propuestas estético-políticas del cine realizado en la región 30 años atrás. También es propósito de esta tesis valorar –sin dejar de cuestionar- la validez y vigencia que los postulados estéticos y políticos, así como las estrategias y tácticas de producción de los años 60, pueden tener para la producción cinematográfica contemporánea del continente, teniendo en cuenta que el circuito cinematográfico comercial –hoy como ayer- priva a las pantallas de las urgencias sociales de América Latina.

Relevância:

10.00% 10.00%

Publicador:

Relevância:

10.00% 10.00%

Publicador:

Resumo:

We have investigated the cellular responses to hydrostatic pressure by using the fission yeast Schizosaccharomyces pombe as a model system. Exposure to sublethal levels of hydrostatic pressure resulted in G2 cell cycle delay. This delay resulted from Cdc2 tyrosine-15 (Y-15) phosphorylation, and it was abrogated by simultaneous disruption of the Cdc2 kinase regulators Cdc25 and Wee1. However, cell cycle delay was independent of the DNA damage, cytokinesis, and cell size checkpoints, suggesting a novel mechanism of Cdc2-Y15 phosphorylation in response to hydrostatic pressure. Spc1/Sty1 mitogen-activated protein (MAP) kinase, a conserved member of the eukaryotic stress-activated p38, mitogen-activated protein (MAP) kinase family, was rapidly activated after pressure stress, and it was required for cell cycle recovery under these conditions, in part through promoting polo kinase (Plo1) phosphorylation on serine 402. Moreover, the Spc1 MAP kinase pathway played a key role in maintaining cell viability under hydrostatic pressure stress through the bZip transcription factor, Atf1. Further analysis revealed that prestressing cells with heat increased barotolerance, suggesting adaptational cross-talk between these stress responses. These findings provide new insight into eukaryotic homeostasis after exposure to pressure stress.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Microencapsulation of drugs into preformed polymers is commonly achieved through solvent evaporation techniques or spray drying. We compared these encapsulation methods in terms of controlled drug release properties of the prepared microparticles and investigated the underlying mechanisms responsible for the “burst release” effect. Using two different pH-responsive polymers with a dissolution threshold of pH 6 (Eudragit L100 and AQOAT AS-MG), hydrocortisone, a model hydrophobic drug, was incorporated into microparticles below and above its solubility within the polymer matrix. Although, spray drying is an attractive approach due to rapid particle production and relatively low solvent waste, the oil-in-oil microencapsulation method is superior in terms of controlled drug release properties from the microparticles. Slow solvent evaporation during the oil-in-oil emulsification process allows adequate time for drug and polymer redistribution in the microparticles and reduces uncontrolled drug burst release. Electron microscopy showed that this slower manufacturing procedure generated non-porous particles whereas thermal analysis and X-ray diffractometry showed that drug loading above the solubility limit of the drug in the polymer generated excess crystalline drug on the surface of the particles. Raman spectral mapping illustrated that drug was homogeneously distributed as a solid solution in the particles when loaded below saturation in the polymer with consequently minimal burst release.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Background: Calpain-10 protein (intracellular Ca2+-dependent cysteine protease) may play a role in glucose metabolism, pancreatic β cell function, and regulation of thermogenesis. Several CAPN10 polymorphic sites have been studied for their potential use as risk markers for type 2 diabetes and the metabolic syndrome (MetS). Fatty acids are key metabolic regulators that may interact with genetic factors and influence glucose metabolism. Objective: The objective was to examine whether the genetic variability at the CAPN10 gene locus is associated with the degree of insulin resistance and plasma fatty acid concentrations in subjects with MetS. Design: The insulin sensitivity index, glucose effectiveness, insulin resistance [homeostasis model assessment of insulin resistance (HOMA-IR)], insulin secretion (disposition index, acute insulin response, and HOMA of β cell function), plasma fatty acid composition, and 5 CAPN10 single nucleotide polymorphisms (SNPs) were determined in a cross-sectional analysis of 452 subjects with MetS participating in the LIPGENE dietary intervention cohort. Results: The rs2953171 SNP interacted with plasma total saturated fatty acid (SFA) concentrations, which were significantly associated with insulin sensitivity (P < 0.031 for fasting insulin, P < 0.028 for HOMA-IR, and P < 0.012 for glucose effectiveness). The G/G genotype was associated with lower fasting insulin concentrations, lower HOMA-IR, and higher glucose effectiveness in subjects with low SFA concentrations (below the median) than in subjects with the minor A allele (G/A and A/A). In contrast, subjects with the G/G allele with the highest SFA concentrations (above the median) had higher fasting insulin and HOMA-IR values and lower glucose effectiveness than did subjects with the A allele. Conclusion: The rs2953171 polymorphism at the CAPN10 gene locus may influence insulin sensitivity by interacting with the plasma fatty acid composition in subjects with MetS. This trial was registered at clinicaltrials.gov as NCT00429195.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Coordinate free conditions are given for pole assignment by feedback in linear descriptor (singular) systems which guarantee closed-loop regularity. These conditions are shown to be both necessary and sufficient for assignment of the maximum possible number of finite poles. Transformation to special coordinates are not used and the results provide a robust algorithm for the computation of the required feedback.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Atmospheric aerosols cause scattering and absorption of incoming solar radiation. Additional anthropogenic aerosols released into the atmosphere thus exert a direct radiative forcing on the climate system1. The degree of present-day aerosol forcing is estimated from global models that incorporate a representation of the aerosol cycles1–3. Although the models are compared and validated against observations, these estimates remain uncertain. Previous satellite measurements of the direct effect of aerosols contained limited information about aerosol type, and were confined to oceans only4,5. Here we use state-of-the-art satellitebased measurements of aerosols6–8 and surface wind speed9 to estimate the clear-sky direct radiative forcing for 2002, incorporating measurements over land and ocean. We use a Monte Carlo approach to account for uncertainties in aerosol measurements and in the algorithm used. Probability density functions obtained for the direct radiative forcing at the top of the atmosphere give a clear-sky, global, annual average of 21.9Wm22 with standard deviation, 60.3Wm22. These results suggest that present-day direct radiative forcing is stronger than present model estimates, implying future atmospheric warming greater than is presently predicted, as aerosol emissions continue to decline10.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Epilepsy is the most common neurological disorder, with over 50 million people worldwide affected. Recent evidence suggests that the transient receptor potential cation channel subfamily V member 1 (TRPV1) may contribute to the onset and progression of some forms of epilepsy. Since the two nonpsychotropic cannabinoids cannabidivarin (CBDV) and cannabidiol (CBD) exert anticonvulsant activity in vivo and produce TRPV1-mediated intracellular calcium elevation in vitro, we evaluated the effects of these two compounds on TRPV1 channel activation and desensitization and in an in vitro model of epileptiform activity. Patch clamp analysis in transfected HEK293 cells demonstrated that CBD and CBDV dose-dependently activate and rapidly desensitize TRPV1, as well as TRP channels of subfamily V type 2 (TRPV2) and subfamily A type 1 (TRPA1). TRPV1 and TRPV2 transcripts were shown to be expressed in rat hippocampal tissue. When tested on epileptiform neuronal spike activity in hippocampal brain slices exposed to a Mg2+-free solution using multielectrode arrays (MEAs), CBDV reduced both epileptiform burst amplitude and duration. The prototypical TRPV1 agonist, capsaicin, produced similar, although not identical effects. Capsaicin, but not CBDV, effects on burst amplitude were reversed by IRTX, a selective TRPV1 antagonist. These data suggest that CBDV antiepileptiform effects in the Mg2+-free model are not uniquely mediated via activation of TRPV1. However, TRPV1 was strongly phosphorylated (and hence likely sensitized) in Mg2+-free solution-treated hippocampal tissue, and both capsaicin and CBDV caused TRPV1 dephosphorylation, consistent with TRPV1 desensitization. We propose that CBDV effects on TRP channels should be studied further in different in vitro and in vivo models of epilepsy.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An explanation of overlapping cusp ion injections is presented using the pulsating cusp model of the effects of magnetopause reconnection. It is shown that two populations of cusp ions, covering separated energy ranges, can be seen simultaneously by low- or mid-altitude satellites because of the combined effect of the acceleration and the straightening of newly-opened field lines as they evolve away from the reconnection site. Observations of such signatures, recently reported in data from the Viking and Freja satellites, are discussed in terms of pulsed and steady reconnection.