Visualitzation and processing of diffusion tensor MRI

Diffusion Tensor Imaging (DTI) is a new magnetic resonance imaging modality capable of producing quantitative maps of microscopic natural displacements of water molecules that occur in brain tissues as part of the physical diffusion process. This technique has become a powerful tool in the investigation of brain structure and function because it allows for in vivo measurements of white matter fiber orientation. The application of DTI in clinical practice requires specialized processing and visualization techniques to extract and represent acquired information in a comprehensible manner. Tracking techniques are used to infer patterns of continuity in the brain by following in a step-wise mode the path of a set of particles dropped into a vector field. In this way, white matter fiber maps can be obtained.

Signal processing of microstructure profiles: integrating turbulent spatial scales in aquatic ecological modeling

The main objective of this thesis was the integration of microstructure information in synoptic descriptors of turbulence, that reflects the mixing processes. Turbulent patches are intermittent in space and time, but they represent the dominant process for mixing. In this work, the properties of turbulent patches were considered the potential input for integrating the physical microscale measurements. The development of a method for integrating the properties of the turbulent patches required solving three main questions: a) how can we detect the turbulent patches from he microstructure measurements?; b) which are the most relevant properties of the turbulent patches?; and ) once an interval of time has been selected, what kind of synoptic parameters could better reflect the occurrence and properties of the turbulent patches? The answers to these questions were the final specific objectives of this thesis.

Advances in animal blood processing: development of a biopreservation system and insights on the functional properties of plasma

La sang és un subproducte amb un alt potencial de valorització que s'obté en quantitats importants en els escorxadors industrials. Actualment, la majoria de sistemes de recollida de la sang no segueixen unes mesures d'higiene estrictes, pel que esdevé un producte de baixa qualitat microbiològica. Conseqüentment, l'aprofitament de la sang és una sortida poc estimulant des del punt de vista econòmic, ja que acostuma a perdre les qualitats que permetrien l'obtenció de productes d'alt valor afegit. El capítol I del present treball s'inclou dins d'un projecte que proposa la inoculació de bacteris de l'àcid làctic (LAB) com un cultiu bioconservador de la sang, un sistema senzill i de baix cost que cerca l'estabilitat de la sang, tant microbiològica com fisicoquímica, durant el període del seu emmagatzematge. El capítol II s'emmarca dins d'un projecte que cerca la millora de l'aprofitament integral de la sang que, en el cas de la fracció plasmàtica, es centra en l'estudi de la funcionalitat dels seus principals constituents. Conèixer la contribució dels components majoritaris ha de permetre la millora de la funcionalitat dels ingredients alimentaris derivats. Els resultats presentats en aquesta tesi poden ajudar a la valorització de la sang porcina d'escorxadors industrials, mitjançant els coneixements adquirits pel que fa a la millora del seu sistema de recollida i del desenvolupament d'ingredients alimentaris amb interessants propietats funcionals.

Using eye-tracking to study anaphoric relations processing in European Portuguese

In this study we evaluate processing costs of different types of anaphoric expressions during reading. We consider three types of anaphoric expressions in Subject sentential position: a null pronoun (pro), and two gaps produced by syntactic movement: a WHvariable and a NP copy. Given that coreferential pro exhibits more referential weight than wh- and NP-gaps, and grounded on theories of referential processing based on relations of hierarchy and accessibility of the antecedent, we raise the hypothesis that the more dependent on its antecedent the anaphoric null constituent is, and the more minimal is the distance in terms of hierarchical structure between the anaphoric null element and its antecedent, the lower are the cognitive costs in processing. To test our hypothesis, we registered the eye movements with R6-HS ASL system of 20 Portuguese adult native speakers. Text regions including the selected anaphoric expressions were delimited and tagged. We analyzed the reading time of each region taking into account the number and duration of eye fixations per region; we used the reading time by character in milliseconds in order to compare values between regions of different length. We found a significant advantage in the reading time of the gaps arising from movement over the reading time of pro.

Evaluating the efficacy of monaural vs. binaural FM fittings in children with auditory processing disorders

The purpose of this project was to determine whether a monaural FM or binaural FM fitting strategy is more appropriate for children with Auditory Processing Disorders.

Effect of auditory processing on the preference of monaural amplification for adults with symmetrical hearing loss

The purpose of this project was to determine if subjects with symmetrical hearing loss who prefer a monaural hearing aid fit to a binaural hearing aid fit may demonstrate an auditory processing disorder causing them to experience binaural interference when fit binaurally.

Are distortion levels a problem with digital signal processing hearing aids and frequency modulation (FM) systems?

The purpose of this study was to examine objective and subjective distortion present when frequency modulation (FM) systems were coupled with four digital signal processing (DSP) hearing aids. Electroacoustic analysis and subjective listening tests by experienced audiologists revealed that distortion levels varied across hearing aids and channels.

The reassessment of central auditory processing disorders in children 7 to 12 years of age

This paper provides a review of central auditory processing disorders in children.

Central auditory processing: a current literature review and summary of interviews with researchers on controversial issues related to auditory processing disorders

This paper discusses issues related to Auditory Processing Disorders (ADP) evaluation and management, focusing mainly on the disorder in children.

Phonological processing in the reading of deaf and normally hearing children

This paper reviews measurement of phonological processes in reading among deaf children and children who are of normal hearing.

Compensatory signal processing for profoundly hearing-impaired listeners: the transmission of fundamental frequency

This paper reviews a study to determine the usefulness of signal processing along with lipreading in improving speech perception of profoundly hearing impaired persons.

Relationship among otoacoustic emission suppression and auditory processing measures in adults

The purpose of this Capstone Project is to help determine whether performing otoacoustic emissions with contralateral noise may be used in the diagnosis of Auditory Processing Disorder.

Pediatric conversion to the HiResolution processing strategy: 6 case studies

This paper presents a study documenting the general trends in the programming techniques, aided behavioral thresholds, speech perception abilities, and overall behavior when converting children into processing strategy called HiResolution (HiRes), used with the Advanced Bionics Clarion II Cochlear Implant System.

Temporal processing in listeners with unilateral hearing loss

Temporal processing is examined for sounds delivered to the intact ear of individuals with unilateral hearing, and delivered to one ear of individuals with normal, bilateral hearing. Two temporal processing skills are assessed: 1) the ability to detect sinusoidal amplitude modulation of a wide-band noise, for various modulation frequencies, and 2) the just-noticeable-difference for temporal complexity of random-spectrogram-sounds.