1000 resultados para external auditory canal


Relevância:

20.00% 20.00%

Publicador:

Resumo:

El present Treball Final de Carrera pretén desenvolupar la viabilitat d’una empresa de serveis, que ofereix un nou suport publicitari basat en una red pròpia de tours turístics en patinets elèctrics distribuïts per les principals ciutats a nivell nacional.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Five to ten percent of benign paroxysmal positional vertigo are caused by the horizontal semi-circular variant (h-BPPV). In this study, we reviewed the efficacy of the Barbecue repositioning manoeuvre in h-BPPV, and we assessed the possible effect of different factors on the outcome. Barbecue manoeuvre consists in turning the supine patient around his longitudinal axis toward the unaffected side until 360 degrees are accomplished. After every 90 degrees step the patient is maintained in the new position for 30 s. We reviewed 46 patients with h-BPPV, treated by barbecue rotation from 2003 to 2005. After the first Barbecue manoeuvre, the patients were followed-up at intervals of approximately 1 week and the rotation was repeated if h-BPPV persisted (up to three rotations). Factors assessed were age, gender, duration of symptoms before treatment and type of h-BPPV (canalolithiasis vs. cupulolithiasis). Fisher's exact test was used for the analysis. Results: 85% of patients (39/46) were cured after a maximum of 3 rotations. 74% (34/46) were cured after the first manoeuvre and 80% (37/46) after the second one. None of the evaluated factors did significantly affect the efficacy (P > 0.05). The Barbecue manoeuvre is an efficient treatment of h-BPPV demonstrating 85% cure rate after a maximum of three sessions. 74% of the patients are healed after one manoeuvre. The efficacy is not affected by the evaluated factors.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A influência de condições halomórficas, hidromórficas e sulfato redutoras na mineralogia da fração argila e na geoquímica de três solos de mangue foi estudada no manguezal do rio Iriri. A partir de uma transeção, foram escolhidos três perfis representativos dos solos de mangue da área nos quais foram descritas as condições geoquímicas e sua conseqüência sobre a mineralogia de seus respectivos solos. A análise mineralógica (DRX e EDS) e as condições físico-químicas encontradas revelam a ocorrência de processos de piritização na área de estudo. A assembléia mineralógica está composta tanto por argilominerais alóctones (caulinitas, micas e esmectitas) como por argilominerais autóctones (micas, esmectitas e pirita). A partir de evidências provenientes da DRX e EDS, especula-se a formação de glauconita nestes solos. As condições de halomorfia e hidromorfia determinam valores de Eh e pH sob os quais elementos como Fe2+ e SO encontram-se livres na solução do solo com tendência à estabilidade da pirita (FeS2), favorecendo, portanto, o processo da piritização.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The pre-Mesozoic metamorphic pattern of the External Massifs, composed of subunits of different metamorphic histories, resulted from the telescoping of Variscan, Ordovician and older metamorphic and structural textures and formations. During an early period, the future External Massifs were part of a peri-Gondwanian microplate evolving as an active margin. Precambrian to lower Palaeozoic igneous and sedimentary protoliths were reworked during an Ordovician subduction cycle (eclogites, granulites) preceding Ordovician anatexis and intrusion of Ordovician granitoids. Little is known about the time period when the microcontinent containing the future External Massifs followed a migration path leading to collision with Laurussia. Corresponding rock-series have not been identified. This might be because they have been eroded or transformed by migmatisation or because they remain hidden in the monocyclic areas. Besides the transformations which originated during the Ordovician subduction cycle, strong metamorphic transformations resulted from Variscan collision when many areas underwent amphibolite facies transformations and migmatisation. The different subunits composing the External Massifs and their corresponding P-T evolution are the expression of different levels in a nappe pile, which may have formed before Visean erosion and cooling. The presence of durbachitic magmatic rocks may be the expression of a large scale Early Variscan upwelling line which formed after Variscan lithospheric subduction. Late Variscan wrench fault tectonics and crustal thinning accompanied by high thermal gradients triggered several pulses of granite intrusions.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Plant circadian clock controls a wide variety of physiological and developmental events, which include the short-days (SDs)-specific promotion of the elongation of hypocotyls during de-etiolation and also the elongation of petioles during vegetative growth. In A. thaliana, the PIF4 gene encoding a phytochrome-interacting basic helix-loop-helix (bHLH) transcription factor plays crucial roles in this photoperiodic control of plant growth. According to the proposed external coincidence model, the PIF4 gene is transcribed precociously at the end of night specifically in SDs, under which conditions the protein product is stably accumulated, while PIF4 is expressed exclusively during the daytime in long days (LDs), under which conditions the protein product is degraded by the light-activated phyB and also the residual proteins are inactivated by the DELLA family of proteins. A number of previous reports provided solid evidence to support this coincidence model mainly at the transcriptional level of the PIF 4 and PIF4-traget genes. Nevertheless, the diurnal oscillation profiles of PIF4 proteins, which were postulated to be dependent on photoperiod and ambient temperature, have not yet been demonstrated. Here we present such crucial evidence on PIF4 protein level to further support the external coincidence model underlying the temperature-adaptive photoperiodic control of plant growth in A. thaliana.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Modern cochlear implantation technologies allow deaf patients to understand auditory speech; however, the implants deliver only a coarse auditory input and patients must use long-term adaptive processes to achieve coherent percepts. In adults with post-lingual deafness, the high progress of speech recovery is observed during the first year after cochlear implantation, but there is a large range of variability in the level of cochlear implant outcomes and the temporal evolution of recovery. It has been proposed that when profoundly deaf subjects receive a cochlear implant, the visual cross-modal reorganization of the brain is deleterious for auditory speech recovery. We tested this hypothesis in post-lingually deaf adults by analysing whether brain activity shortly after implantation correlated with the level of auditory recovery 6 months later. Based on brain activity induced by a speech-processing task, we found strong positive correlations in areas outside the auditory cortex. The highest positive correlations were found in the occipital cortex involved in visual processing, as well as in the posterior-temporal cortex known for audio-visual integration. The other area, which positively correlated with auditory speech recovery, was localized in the left inferior frontal area known for speech processing. Our results demonstrate that the visual modality's functional level is related to the proficiency level of auditory recovery. Based on the positive correlation of visual activity with auditory speech recovery, we suggest that visual modality may facilitate the perception of the word's auditory counterpart in communicative situations. The link demonstrated between visual activity and auditory speech perception indicates that visuoauditory synergy is crucial for cross-modal plasticity and fostering speech-comprehension recovery in adult cochlear-implanted deaf patients.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In the general discussion on the Variscan evolution of central Europe the pre-Mesozoic basement of the Alps is, in many cases, only included with hesitation. Relatively well-preserved from Alpine metamorphism, the Alpine External massifs can serve as an excellent example of evolution of the Variscan basement, including the earliest Gondwana-derived microcontinents with Cadomian relics. Testifying to the evolution at the Gondwana margin, at least since the Cambrian, such pieces took part in the birth of the Rheic Ocean. After the separation of Avalonia, the remaining Gondwana border was continuously transformed through crustal extension with contemporaneous separation of continental blocks composing future Pangea, but the opening of Palaeotethys had only a reduced significance since the Devonian. The Variscan evolution in the External domain is characterised by an early HP-evolution with subsequent granulitic decompression melts. During Visean crustal shortening, the areas of future formation of migmatites and intrusion of monzodioritic magmas in a general strike-slip regime, were probably in a lower plate situation, whereas the so called monometamorphic areas may have been in an upper plate position of the nappe pile. During the Latest Carboniferous, the emplacement of the youngest granites was associated with the strike-slip faulting and crustal extension at lower crustal levels, whereas, at the surface, detrital sediments accumulated in intramontaneous transtensional basins on a strongly eroded surface. To cite this article: J.R von Raumer et al., C. R. Geoscience 341 (2009). (C) 2008 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Auditory spatial representations are likely encoded at a population level within human auditory cortices. We investigated learning-induced plasticity of spatial discrimination in healthy subjects using auditory-evoked potentials (AEPs) and electrical neuroimaging analyses. Stimuli were 100 ms white-noise bursts lateralized with varying interaural time differences. In three experiments, plasticity was induced with 40 min of discrimination training. During training, accuracy significantly improved from near-chance levels to approximately 75%. Before and after training, AEPs were recorded to stimuli presented passively with a more medial sound lateralization outnumbering a more lateral one (7:1). In experiment 1, the same lateralizations were used for training and AEP sessions. Significant AEP modulations to the different lateralizations were evident only after training, indicative of a learning-induced mismatch negativity (MMN). More precisely, this MMN at 195-250 ms after stimulus onset followed from differences in the AEP topography to each stimulus position, indicative of changes in the underlying brain network. In experiment 2, mirror-symmetric locations were used for training and AEP sessions; no training-related AEP modulations or MMN were observed. In experiment 3, the discrimination of trained plus equidistant untrained separations was tested psychophysically before and 0, 6, 24, and 48 h after training. Learning-induced plasticity lasted <6 h, did not generalize to untrained lateralizations, and was not the simple result of strengthening the representation of the trained lateralizations. Thus, learning-induced plasticity of auditory spatial discrimination relies on spatial comparisons, rather than a spatial anchor or a general comparator. Furthermore, cortical auditory representations of space are dynamic and subject to rapid reorganization.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The kitten's auditory cortex (including the first and second auditory fields AI and AII) is known to send transient axons to either ipsi- or contralateral visual areas 17 and 18. By the end of the first postnatal month the transitory axons, but not their neurons of origin, are eliminated. Here we investigated where these neurons project after the elimination of the transitory axon. Eighteen kittens received early (postnatal day (pd) 2 - 5) injections of long lasting retrograde fluorescent traces in visual areas 17 and 18 and late (pd 35 - 64) injections of other retrograde fluorescent tracers in either hemisphere, mostly in areas known to receive projections from AI and AII in the adult cat. The middle ectosylvian gyrus was analysed for double-labelled neurons in the region corresponding approximately to AI and AII. Late injections in the contralateral (to the analysed AI, AII) hemisphere including all of the known auditory areas, as well as some visual and 'association' areas, did not relabel neurons which had had transient projections to either ipsi- or contralateral visual areas 17 - 18. Thus, AI and AII neurons after eliminating their transient juvenile projections to visual areas 17 and 18 do not project to the other hemisphere. In contrast, relabelling was obtained with late injections in several locations in the ipsilateral hemisphere; it was expressed as per cent of the population labelled by the early injections. Few neurons (0 - 2.5%) were relabelled by large injections in the caudal part of the posterior ectosylvian gyrus and the adjacent posterior suprasylvian sulcus (areas DP, P, VP). Multiple injections in the middle ectosylvian gyrus relabelled a considerably larger percentage of neurons (13%). Single small injections in the middle ectosylvian gyrus (areas AI, AII), the caudal part of the anterior ectosylvian gyrus and the rostral part of the posterior ectosylvian gyrus relabelled 3.1 - 7.0% of neurons. These neurons were generally near (&lt;2.0 mm) the outer border of the late injection sites. Neurons with transient projections to ipsi- or contralateral visual areas 17 and 18 were relabelled in similar proportions by late injections at any given location. Thus, AI or AII neurons which send a transitory axon to ipsi- or contralateral visual areas 17 and 18 are most likely to form short permanent cortical connections. In that respect, they are similar to medial area 17 neurons that form transitory callosal axons and short permanent axons to ipsilateral visual areas 17 and 18.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

En la última década, distintos estudios han intentado contrastar empíricamente la existencia de una relación entre el stock de capital humanolocal y la productividad del territorio, así como la posible presencia de economías externas asociadas a aquél. El resultado común de dichos estudios ha consistido en encontrar una correlación positiva entre ambas variables Losdiversos autores no coinciden, en cambio, a la hora de explicar dicho resultado: un primer grupo de autores argumenta la presencia de economíasexternas vinculadas al capital humano mientras que un segundo grupo plantea la existencia de relaciones de complementariedad entre los diversos factores productivos y, más en concreto, entre el capital humano y el capital físico.El objetivo de este trabajo es analizar la existencia de una posible relación positiva entre el nivel de capital humano de las provincias españolas y su productividad de éstas y, a continuación, averiguar si el canal a través delcual se produce el efecto son las economías externas. Para ello, se aplica unametodología que consta de dos etapas. En la primera, se estima una ecuación de Mincer utilizando información de la Encuesta de Presupuestos Familiares a fin de obtener una estimación de la productividad media de cada una de las provincias españolas una vez controlado el efecto del capital humano de los individuos sobre su propia productividad. En una segunda etapa, la estimación de la productividad provincial media estimada se introduce como variable endógena en una nueva ecuación cuyas variables explicativas intentan aproximar el nivel de capital humano de cada una de las provincias. A partir de esta segunda regresión se detecta una relación positiva entre la productividad media estimada del territorio y el nivel educativo medio delmismo. Sin embargo, la principal conclusión del análisis realizado es que dicha relación no puede explicarse por el impacto de las economías externas generadas exógenamente por el capital humano, sino que debe atribuirse a otros efectos que, actuando también por lado de la demanda, impulsen al alza la productividad.