From dysfunctional to extraordinary verbal repetition abilities: clinical implications and neural features

Three cases are presented to index the hypothesis that mitigated echolalia emerges from overreliance on the dorsal language stream, through the arcuate fasciculus, when the ventral stream is damaged; whereas conduite d’approche ensues when the ventral stream attempts to compensate a dorsal damage. The role of the right hemisphere and other alternative pathways in both cerebral hemispheres in the successful compensation of brain injury is also discussed. Further, Study 2 reconceptualizes different types of echolalia within a continuous of severity and communication capacity. To accomplish this new instantiation, it is proposed that different types of echolalia may be associated to failure in distinctive linguistic and non-linguistic cognitive functions. Recommendations for its evaluation and treatment are provided, suggesting that echolalia interfering with functional communication should be treated. Further, complementing the previous one, Study 3 reports a comprehensive single case study exploring response to treatment, and behavioral and neuroimaging features of a person with mitigated echolalia associated to a chronic fluent aphasia. Findings from such case include a reduction of mitigated echolalia after two weeks of intensive aphasia therapy as well as the maintenance of these gains with memantine alone for at least 6 months. Importantly, reduction of mitigated echolalia instances in response to treatment speeded up the time needed to complete comprehension tasks. Neuroimaging results, although indirectly, suggested that mitigated echolalia may be supported by the activity of the remaining components of the left dorsal stream and compensatory right hemisphere recruitment. Additionally, to further explore the neural and cognitive mechanisms involved in verbal repetition in a model of language expertise, Study 4 tackles cognitive features and neural correlates of verbal expertise in two healthy adult subjects displaying an extraordinary ability to orally reverse language, a condition referred to as backward speech. Results suggest that phonological expertise, as shown in backward speech, involves reshaping (or pre-existent differences) of cortical areas and tracts relevant for auditory-motor integration and semantic processing. Greater functional coupling between critical language areas and domain-general and high-order visual areas may further support reversing processes. Lastly, Study 5 presents a systematic review of the literature aimed to examine sex differences in the prevalence of repetition deficits in persons with post-stroke aphasia. Results show that the proportion of females in the group of aphasia characterized by repetition deficits (i.e., conduction aphasia) is lower than the expected by the prevalence of stroke among them. It is suggested that sex-related differences in the volume of areas of the right hemisphere homologues to the ones subserving repetition in the left hemisphere may be at the base of this difference. This finding poses sex as a relevant variable to account for variance in repetition abilities, and as a relevant factor to consider in future studies of language acquisition, maturation, and relearning promoted by aphasia therapy. Fecha de lectura de Tesis Doctoral: 16 de diciembre 2019Verbal repetition and audio-visual imitation stand as crucial functions for the acquisition and maturation of language in childhood, language learning in adulthood, and a major resource for language recovery after brain damage. Although modern neuroimaging techniques have allowed the identification of the brain areas involved in repetition tasks in healthy subjects, many clinical and neural aspects of this linguistic function are still overlooked in persons with aphasia and in emerging models of language expertise. Therefore, the present dissertation aims to explore cognitive correlates and neural features of verbal repetition from different perspectives including models of dysfunctional repetition (i.e., people with aphasia) and language expertise (i.e., healthy backward speakers). Generally, this thesis explores the potential of the dorsal and ventral components of the neural network supporting verbal repetition to assume, under certain circumstances (e.g., brain damage or extraordinary abilities), non-canonical functions. Further, this dissertation addresses clinical issues of some aphasic symptoms characterized by uncontrolled repetition (i.e., echolalia), as well as reviews sex as a source of variability in verbal repetition outcomes after brain damage. This dissertation includes five studies that are part of this dissertation. First, it reviews the mechanisms involved in dysfunctional repetition, especially in two repetitive verbal behaviors named conduite d’approche and mitigated echolalia (Study 1) and addresses clinical issues of the last one (Study 2 and 3). In this regard, Study 1 proposes that in the context of aphasia these symptoms (i.e., conduite d’approche and mitigated echolalia) may represent active attempts of verbal communication, rather than inconsequential repetitive verbal behaviors resulting from maladaptive neural changes

Static and Rotordynamic Characteristics of Liquid Annular Seals with a Circumferentially-Grooved Stator and Smooth Rotor using Three Levels of Circumferential Inlet-Fluid Rotation

Original Equipment Manufacturers (OEMs) increase pump efficiency by reducing process fluid leakage from high-pressure stages into low-pressure ones. Smooth, liquid annular seals are used between pump stages to achieve this goal. In an effort to reduce leakage, OEMs sometimes machine circumferential grooves in the stators of annular liquid seals. Unfortunately, grooved seals do more than improve pump efficiency; they sometimes help degrade the system’s (pump, motor) rotordynamics, causing adverse effects that overshadow its helpful qualities. The rotordynamic community recognizes that fluid rotating in the shaft direction, at the entrance of the seal, is a source instability. The relevant literature lacks test results showing how high levels of inlet-fluid rotation affect a grooved seal’s performance, and how this effect changes as the shaft operates very close to the stator. The present study addresses this lack. Supplied with VG2 oil @ 46 ⁰C (115 ⁰F), the grooved seal used for this investigation has a length-to-diameter ratio L/D of 0.5, and a minimum radial clearance Cr of 203 ?m (8 mil). It features 15 circumferential grooves with a length Gl, and depth Gd of 1.52 mm (60 mils), which are equally-spaced by a land length of 1.52 mm (60 mils). The experimenter conducts tests at shaft angular speeds w of 2, 4, and 6 krpm, eccentricity ratios e0 of 0.00, 0.27, 0.53, and 0.80, and axial pressure drops ?P of 2.1, 4.1, 6.2, 8.3 bar (30, 60, 90, 120 PSI). Using 3 distinct inlet-fluid rotation inserts, the author induces increasing levels of circumferential fluid velocity at the seal’s inlet. Pre-swirl ratio (PSR) and outlet swirl ratio (OSR) are defined as the ratio of circumferential velocity at the seal’s inlet and outlet, respectively, to the rotor’s tangential surface velocity. To assess the seal’s static performance, the author measures leakage rate Q, eccentricity ratio e0, PSR, and OSR. To assess the seal’s dynamic performance, the author measures stator-rotor relative displacement, stator acceleration, and dynamic excitations. The author uses the dynamic measurements to calculate the seal’s rotordynamic coefficients and Whirl Frequency Ratio (WFR). Finally, the author calculates effective stiffness and damping coefficients to compare the grooved seal’s rotordynamic performance to that of a smooth seal with the same Cr, L/D, and operating conditions. In regards to static performance, the grooved seal’s leakage rate ranges from a low 15.64 LPM (4.13 GPM) at w = 6 krpm, and ?P = 2 bar (30 PSI), to a high 56.36 LPM (14.16 GPM) at w = 2 krpm, and ?P = 8 bar (120 PSI). When compared to the smooth seal, the grooved seal provides a 20% Q reduction at w = 2 krpm, and a 6% reduction at w = 6 krpm. Test results show all of the smooth seal’s rotordynamic coefficients increase markedly for e0 > 0.50, while those of the grooved seal generally remain unchanged through the entire eccentricity range. In essence, the grooves eliminate the seal’s dependency on eccentricity. Next, the grooved seal generally produces lower-magnitude cross-coupled stiffness and damping coefficient values than the smooth seal. Furthermore, the only positive effective stiffness values arise from the smooth seal operating at w = 2 krpm. The smooth seal consistently produces higher Keff than the grooved seal. Specifically, the smooth seal’s effective stiffness is higher than that of the grooved seal by at least 30% at w = 6 krpm, across the ?P range, for e0 = 0.00. Also, the grooved seal’s measured OSR is lower than that of the smooth seal by at least 10%, across the test matrix, suggesting that the grooves effectively slow down circumferential flow. For the grooved seal, the test program measures PSR values ranging from ?0 to 0.98, and OSR values bounded between 0.21 and 0.34. At w = 2 krpm, increasing PSR across its range reduces the grooved seal’s direct stiffness and damping, drives its cross-coupled stiffness and damping away from zero, increases its whirl frequency ratio (WFR) from ?0 to 0.8, and reduces its effective damping by a factor of approximately 3.5 when operating at ?P = 8.3 bar [120 PSI]. In general, the smooth seal produces larger effective stiffness and damping coefficients than the grooved seal, highlighting the grooves’ adverse effect on seal rotordynamics. Using XLCGvr, a code that calculates Q and rotordynamic coefficients for centered, circumferentially-grooved annular seals, the author performs a measurement-vs.-prediction comparison. The code over predicts Q by at least 15%. The stiffness, damping, and virtual mass coefficients are all under predicted by at least 50%. While the author used the code’s default empirical parameters, modifying them could have improved its accuracy

The importance of administrative data in the evaluation of the incidence of social housing allowance programmes

The aim of this work is to assess the rental assistance programme that was implemented by the Catalan regional government in the 2010s using administrative data provided by the Catalonia Housing Agency to analyse whether it achieved its aims to enhance the design of similar programmes. Linear probability models to explain the probability of receiving the grant were estimated and some significant variables were identified: age; rent price; expertise; being a woman; non-EU citizenship and the number of old, young or disabled members. Multiple regressions were estimated in regard to the grant’s rate in relation to the rent price and the effort required to pay relative to income after having received the grant. The results suggest that rental assistance facilitates access to housing to groups that face more difficulties and that the revenue captured by landlords, although statistically significant, is small, since they capture approximately 3% by raising prices. This aid, despite being controlled by different variables, benefits elderly people more than young people, which must be addressed because, theoretically, when access requirements are met, no group should benefit more than others

Influence of tangent pinch points on the energy demand of batch distillations: Development of a conceptual model for binary mixtures

This contribution explores the influence of tangent pinch points on the performance of batch distillations of highly nonideal binary mixtures and its incorporation into a conceptual modeling framework under the assumption of a rectifier with an infinite number of stages. First of all, the y−x diagram is divided into three regions taking into account both the inflection point (IP) in the phase diagram and the slope of the equilibrium curve at xD = 1. After that, limiting values for the reflux ratio and distillate composition; namely, r* and xD*, are calculated for the instantaneous still composition xB with the aid of region-dependent algorithms, which incorporate the tangency condition in different ways. Finally, the instantaneous column performance is estimated taking into account the selected operation mode; i.e., constant reflux ratio or constant distillate composition. Applied to the mixture acetone−water, results for complete simulations are presented in terms of both rectification advance and operation time. A brief comparative study on the minimum energy demand required for a given separation as estimated from models with and without tangent pinches is also carried out.Fil: Torres, Karina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo y Diseño. Universidad Tecnológica Nacional. Facultad Regional Santa Fe. Instituto de Desarrollo y Diseño; ArgentinaFil: Espinosa, Hector Jose Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo y Diseño. Universidad Tecnológica Nacional. Facultad Regional Santa Fe. Instituto de Desarrollo y Diseño; Argentin

Static and Rotordynamic Characteristics of Liquid Annular Seals with a Circumferentially-Grooved Stator and Smooth Rotor using Three Levels of Circumferential Inlet-Fluid Rotation

Original Equipment Manufacturers (OEMs) increase pump efficiency by reducing process fluid leakage from high-pressure stages into low-pressure ones. Smooth, liquid annular seals are used between pump stages to achieve this goal. In an effort to reduce leakage, OEMs sometimes machine circumferential grooves in the stators of annular liquid seals. Unfortunately, grooved seals do more than improve pump efficiency; they sometimes help degrade the system’s (pump, motor) rotordynamics, causing adverse effects that overshadow its helpful qualities. The rotordynamic community recognizes that fluid rotating in the shaft direction, at the entrance of the seal, is a source instability. The relevant literature lacks test results showing how high levels of inlet-fluid rotation affect a grooved seal’s performance, and how this effect changes as the shaft operates very close to the stator. The present study addresses this lack. Supplied with VG2 oil @ 46 ⁰C (115 ⁰F), the grooved seal used for this investigation has a length-to-diameter ratio L/D of 0.5, and a minimum radial clearance Cr of 203 ?m (8 mil). It features 15 circumferential grooves with a length Gl, and depth Gd of 1.52 mm (60 mils), which are equally-spaced by a land length of 1.52 mm (60 mils). The experimenter conducts tests at shaft angular speeds w of 2, 4, and 6 krpm, eccentricity ratios e0 of 0.00, 0.27, 0.53, and 0.80, and axial pressure drops ?P of 2.1, 4.1, 6.2, 8.3 bar (30, 60, 90, 120 PSI). Using 3 distinct inlet-fluid rotation inserts, the author induces increasing levels of circumferential fluid velocity at the seal’s inlet. Pre-swirl ratio (PSR) and outlet swirl ratio (OSR) are defined as the ratio of circumferential velocity at the seal’s inlet and outlet, respectively, to the rotor’s tangential surface velocity. To assess the seal’s static performance, the author measures leakage rate Q, eccentricity ratio e0, PSR, and OSR. To assess the seal’s dynamic performance, the author measures stator-rotor relative displacement, stator acceleration, and dynamic excitations. The author uses the dynamic measurements to calculate the seal’s rotordynamic coefficients and Whirl Frequency Ratio (WFR). Finally, the author calculates effective stiffness and damping coefficients to compare the grooved seal’s rotordynamic performance to that of a smooth seal with the same Cr, L/D, and operating conditions. In regards to static performance, the grooved seal’s leakage rate ranges from a low 15.64 LPM (4.13 GPM) at w = 6 krpm, and ?P = 2 bar (30 PSI), to a high 56.36 LPM (14.16 GPM) at w = 2 krpm, and ?P = 8 bar (120 PSI). When compared to the smooth seal, the grooved seal provides a 20% Q reduction at w = 2 krpm, and a 6% reduction at w = 6 krpm. Test results show all of the smooth seal’s rotordynamic coefficients increase markedly for e0 > 0.50, while those of the grooved seal generally remain unchanged through the entire eccentricity range. In essence, the grooves eliminate the seal’s dependency on eccentricity. Next, the grooved seal generally produces lower-magnitude cross-coupled stiffness and damping coefficient values than the smooth seal. Furthermore, the only positive effective stiffness values arise from the smooth seal operating at w = 2 krpm. The smooth seal consistently produces higher Keff than the grooved seal. Specifically, the smooth seal’s effective stiffness is higher than that of the grooved seal by at least 30% at w = 6 krpm, across the ?P range, for e0 = 0.00. Also, the grooved seal’s measured OSR is lower than that of the smooth seal by at least 10%, across the test matrix, suggesting that the grooves effectively slow down circumferential flow. For the grooved seal, the test program measures PSR values ranging from ?0 to 0.98, and OSR values bounded between 0.21 and 0.34. At w = 2 krpm, increasing PSR across its range reduces the grooved seal’s direct stiffness and damping, drives its cross-coupled stiffness and damping away from zero, increases its whirl frequency ratio (WFR) from ?0 to 0.8, and reduces its effective damping by a factor of approximately 3.5 when operating at ?P = 8.3 bar [120 PSI]. In general, the smooth seal produces larger effective stiffness and damping coefficients than the grooved seal, highlighting the grooves’ adverse effect on seal rotordynamics. Using XLCGvr, a code that calculates Q and rotordynamic coefficients for centered, circumferentially-grooved annular seals, the author performs a measurement-vs.-prediction comparison. The code over predicts Q by at least 15%. The stiffness, damping, and virtual mass coefficients are all under predicted by at least 50%. While the author used the code’s default empirical parameters, modifying them could have improved its accuracy

Fiscal policy, the current account, and the twin deficits hypothesis

Relationship between Öscal policy and the current account. Traditional view suggests that a Öscal expansion should lead to a worsening in the current account, contrary to the Ricardian view, in which there is no systematic relationship between budget and current account deficits.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec

Preferencia por cepa carménére de parte de los consumidores de vino en la región del Maule: un análisis conjunto.

82 p.El trabajo que se presenta a continuación muestra un análisis de la preferencia de los consumidores de Vino en la Región del Maule mediante atributos diferenciadores, para lo cual se realizó una revisión bibliográfica la que permitió definir el marco conceptual y la metodología a aplicar. Entre las diferentes técnicas de análisis de preferencias se eligió el “Análisis Conjunto”. Una vez escogido el método, se procedió a construir una encuesta la cual incluyera atributos diferenciadores relevantes para el estudio, y se aplicó a las 10 comunas más pobladas de la región del Maule, los atributos utilizados fueron: cepa de vino, sistema de producción utilizado, región de origen, y precio. El siguiente paso consistió en determinar una matriz de combinaciones de los atributos y a través de ésta se les solicitó a los encuestados que ordenaran sus preferencias de consumo y adicionalmente que determinaran una nota en relación a los atributos ofrecidos en 9 productos. Así se logró cubrir con nuestros objetivos específicos y determinar la utilidad que dichos atributos le proporcionaban. Adicionalmente, entre los análisis efectuados, se consideró sólo aquellos encuestados que preferían la cepa Carménère a fin de determinar las preferencias entre los productos ofrecidos, como resultado se obtuvo que la cepa ya no es el atributo que entrega mayor utilidad, lo que nos indica que para un mercado de consumidores definido es necesario incorporar otras variables que atraigan el consumo del vino. Lo antes descrito se desarrolla en cinco secciones basadas en el método científico: marco teórico, metodología, análisis de resultados y finalmente las conclusiones

Implementation of an effective time-saving two-stage methodology for microstructural characterization of cemented carbides

Linear intercept on scanning electron microscopy micrographs is the most commonly used measurement method to determine carbide grain size and contiguity in WC–Co cemented carbides (hardmetals). However, it involves manual time-consuming measurements and is critically dependent on the quality of the micrographs as well as on the identification and definition of grain boundaries. In this study a two-stage methodology for microstructural characterization of hardmetals is presented. First, a digital semi-automatic image analysis procedure for grain size determination of the carbide phase is presented. It involves an experimental assessment of grain size on processed images corresponding to a series of WC–Co and WC–Ni cemented carbide grades with different microstructural characteristics. Obtained results are then compared to the values obtained by means of the linear intercept technique. A good correlation between the mean grain sizes determined following both measurement techniques was attained. Based on experimental findings, a series of empirical relations were found to correlate grain size distributions obtained following both methods. Second, an empirical relation for estimating carbide contiguity in WC–Co cemented carbides is proposed. This relation considers simultaneously the influence of the binder content and the experimentally determined mean grain size on contiguity. The proposed equation for contiguity estimation is based on extensive data collection from open literature. An excellent agreement was attained between contiguity values estimated from such equation and those obtained using the linear intercept technique. This validates the two-stage procedure as an effective time-saving methodology for microstructural characterization of WC–Co cemented carbides.Peer ReviewedPostprint (author's final draft