Classification of EMG signals to control a prosthetic hand using time-frequesncy representations and Support Vector Machines

Myoelectric signals (MES) are viable control signals for externally-powered prosthetic devices. They may improve both the functionality and the cosmetic appearance of these devices. Conventional controllers, based on the signal\u27s amplitude features in the control strategy, lack a large number of controllable states because signals from independent muscles are required for each degree of freedom (DoF) of the device. Myoelectric pattern recognition systems can overcome this problem by discriminating different residual muscle movements instead of contraction levels of individual muscles. However, the lack of long-term robustness in these systems and the design of counter-intuitive control/command interfaces have resulted in low clinical acceptance levels. As a result, the development of robust, easy to use myoelectric pattern recognition-based control systems is the main challenge in the field of prosthetic control. This dissertation addresses the need to improve the controller\u27s robustness by designing a pattern recognition-based control system that classifies the user\u27s intention to actuate the prosthesis. This system is part of a cost-effective prosthetic hand prototype developed to achieve an acceptable level of functional dexterity using a simple to use interface. A Support Vector Machine (SVM) classifier implemented as a directed acyclic graph (DAG) was created. It used wavelet features from multiple surface EMG channels strategically placed over five forearm muscles. The classifiers were evaluated across seven subjects. They were able to discriminate five wrist motions with an accuracy of 91.5%. Variations of electrode locations were artificially introduced at each recording session as part of the procedure, to obtain data that accounted for the changes in the user\u27s muscle patterns over time. The generalization ability of the SVM was able to capture most of the variability in the data and to maintain an average classification accuracy of 90%. Two principal component analysis (PCA) frameworks were also evaluated to study the relationship between EMG recording sites and the need for feature space reduction. The dimension of the new feature set was reduced with the goal of improving the classification accuracy and reducing the computation time. The analysis indicated that the projection of the wavelet features into a reduced feature space did not significantly improve the accuracy and the computation time. However, decreasing the number of wavelet decomposition levels did lower the computational load without compromising the average signal classification accuracy. Based on the results of this work, a myoelectric pattern recognition-based control system that uses an SVM classifier applied to time-frequency features may be used to discriminate muscle contraction patterns for prosthetic applications

Evaluation of Chewing and Swallowing Sensors for Monitoring Ingestive Behavior

Monitoring Ingestive Behavior (MIB) of individuals is of special importance to identify and treat eating patterns associated with obesity and eating disorders. Current methods for MIB require subjects reporting every meal consumed, which is burdensome and tend to increase the reporting bias over time. This study presents an evaluation of the burden imposed by two wearable sensors for MIB during unrestricted food intake: a strain sensor to detect chewing events and a throat microphone to detect swallowing sounds. A total of 30 healthy subjects with various levels of adiposity participated in experiments involving the consumption of four meals in four different visits. A questionnaire was handled to subjects at the end of the last visit to evaluate the sensors burden in terms of the comfort levels experienced. Results showed that sensors presented high comfort levels as subjects indicated that the way they ate their meal was not considerably affected by the presence of the sensors. A statistical analysis showed that chewing sensor presented significantly higher comfort levels than the swallowing sensor. The outcomes of this study confirmed the suitability of the chewing and swallowing sensors for MIB and highlighted important aspects of comfort that should be addressed to obtain acceptable and less burdensome wearable sensors for MIB.Fil: Fontana, Juan Manuel. University of Alabama; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Sazonov, Edward S.. University of Alabama; Estados Unido

Rafael Barret, una incómoda anomalía para <i>La ciudad letrada</i>

En los tramos finales de La ciudad letrada, Rama polemiza con la visión del modernismo latinoamericano defendida por Henríquez Ureña. Lejos de concebirlos como literatos puros, como hombres de letras desvinculados de la política, el crítico uruguayo sostiene que los escritores de la época no dudaron en ejercer el monopolio de los servicios culturales en favor de los sectores dominantes. En el curso de su argumentación, Rama se refiere a un grupo selecto de ensayistas con el propósito de ilustrar su tesis del intelectual latinoamericano en tanto ideólogo del poder hegemónico. Incluye, entre ellos, a una de las figuras más emblemáticas y olvidadas de la escena cultural rioplatense del novecientos: Rafael Barret. El seguimiento de la heterodoxa trayectoria barretiana deja pues al descubierto uno de los problemas fundamentales del enfoque de Rama: su incapacidad a la hora de reconocer la existencia de prácticas discursivas contestatarias e indóciles respecto del poder. De ese modo, retornar a Barret, revisitar su intensa y anómala praxis político-literaria, es también mostrar las fisuras de La ciudad letrada.In the final sections of The Literate City, Rama polemicizes with the vision of Latin American modernism defended by Henríquez Ureña. Far from conceiving them as pure writers, as men of letters unrelated to politics, the Uruguayan critic maintains that the writers of the time did not hesitate to exercise a monopoly on cultural services in favor of the dominant sectors. In the course of his argumentation, Rama refers to a select group of essayists with the purpose of illustrating his thesis of the Latin American intellectual as ideologist of hegemonic power. It includes, among them, one of the most emblematic and forgotten figures of the River Plate cultural scene of the nine hundred: Rafael Barret. Following the heterodox Barretian trajectory thus reveals one of the fundamental problems of Rama's approach: his inability to recognize the existence of discursive and unruly discursive practices regarding power. In this way, returning to Barret, revisiting his intense and anomalous political-literary praxis is also showing the fissures of The Literate City.Facultad de Humanidades y Ciencias de la Educació

Rafael Barret, una incómoda anomalía para <i>La ciudad letrada</i>

En los tramos finales de La ciudad letrada, Rama polemiza con la visión del modernismo latinoamericano defendida por Henríquez Ureña. Lejos de concebirlos como literatos puros, como hombres de letras desvinculados de la política, el crítico uruguayo sostiene que los escritores de la época no dudaron en ejercer el monopolio de los servicios culturales en favor de los sectores dominantes. En el curso de su argumentación, Rama se refiere a un grupo selecto de ensayistas con el propósito de ilustrar su tesis del intelectual latinoamericano en tanto ideólogo del poder hegemónico. Incluye, entre ellos, a una de las figuras más emblemáticas y olvidadas de la escena cultural rioplatense del novecientos: Rafael Barret. El seguimiento de la heterodoxa trayectoria barretiana deja pues al descubierto uno de los problemas fundamentales del enfoque de Rama: su incapacidad a la hora de reconocer la existencia de prácticas discursivas contestatarias e indóciles respecto del poder. De ese modo, retornar a Barret, revisitar su intensa y anómala praxis político-literaria, es también mostrar las fisuras de La ciudad letrada.In the final sections of The Literate City, Rama polemicizes with the vision of Latin American modernism defended by Henríquez Ureña. Far from conceiving them as pure writers, as men of letters unrelated to politics, the Uruguayan critic maintains that the writers of the time did not hesitate to exercise a monopoly on cultural services in favor of the dominant sectors. In the course of his argumentation, Rama refers to a select group of essayists with the purpose of illustrating his thesis of the Latin American intellectual as ideologist of hegemonic power. It includes, among them, one of the most emblematic and forgotten figures of the River Plate cultural scene of the nine hundred: Rafael Barret. Following the heterodox Barretian trajectory thus reveals one of the fundamental problems of Rama's approach: his inability to recognize the existence of discursive and unruly discursive practices regarding power. In this way, returning to Barret, revisiting his intense and anomalous political-literary praxis is also showing the fissures of The Literate City.Facultad de Humanidades y Ciencias de la Educació

A novel approach for food intake detection using electroglottography

Many methods for monitoring diet and food intake rely on subjects self-reporting their daily intake. These methods are subjective, potentially inaccurate and need to be replaced by more accurate and objective methods. This paper presents a novel approach that uses an electroglottograph (EGG) device for an objective and automatic detection of food intake. Thirty subjects participated in a four-visit experiment involving the consumption of meals with self-selected content. Variations in the electrical impedance across the larynx caused by the passage of food during swallowing were captured by the EGG device. To compare performance of the proposed method with a well-established acoustical method, a throat microphone was used for monitoring swallowing sounds. Both signals were segmented into non-overlapping epochs of 30 s and processed to extract wavelet features. Subject-independent classifiers were trained, using artificial neural networks, to identify periods of food intake from the wavelet features. Results from leave-one-out cross validation showed an average per-epoch classification accuracy of 90.1% for the EGG-based method and 83.1% for the acoustic-based method, demonstrating the feasibility of using an EGG for food intake detection.Fil: Farooq, Muhammad. University of Alabama; Estados UnidosFil: Fontana, Juan Manuel. University of Alabama; Estados Unidos. Universidad Nacional de Río Cuarto. Facultad de Ingeniería. Departamento de Mecánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Sazonov, Edward. University of Alabama; Estados Unido

Descolonizar el saber, transformar nuestras prácticas educativas : El pensar filosófico más allá del canon eurocéntrico

En el contexto de una educación institucionalizada que permanece bajo la preeminencia del paradigma epistemológico nortecéntrico, cabe interrogarnos por las condiciones de posibilidad para avanzar hacia prácticas pedagógicas liberadoras. El eje central del artículo remite pues a las “heridas coloniales” que el actual proceso de globalización hegemónica inflige sobre los actores que intervienen en el campo educativo, concebidos como sujetos epistémicos (re)productores y administradores de un saber eurocentrado. Asumiendo que los diseños curriculares tienden a funcionar como engranajes fundamentales del eurocentrismo epistémico, se realiza un estudio crítico del Diseño Curricular de Filosofía (DCF) actualmente vigente para educación media en la provincia de Buenos Aires. En el curso de este análisis, se pone en evidencia que dicha propuesta de enseñanza concede privilegio epistémico a la tradición canónica, al tiempo que silencia Otras voces filosóficas con capacidad para representar, problematizar y experimentar el mundo con arreglo a otros términos, necesidades y aspiraciones sociales. Por último, y como intento de superación de las modalidades que asume la colonización intelectual en nuestros contextos educativos periféricos, se explora la relevancia social y pedagógica de una concepción posabismal del saber.In the context of an institutionalized education that remains under the preeminence of the northcentric epistemological paradigm, we can ask ourselves about the conditions of possibility to move towards liberating pedagogical practices. The central axis of the article thus refers to the “colonial wounds” that the current hegemonic globalization process inflicts on the actors involved in the educational field, conceived as epistemic subjects (re)producers and administrators of a Eurocentrated knowledge. Assuming that curricular designs tend to function as fundamental gears of epistemic Eurocentrism, is carried out a critical study of the Curricular Design of Philosophy (DCF) is currently in force for secondary education in the province of Buenos Aires. In the course of this analysis, it becomes clear that this teaching proposal grants epistemic privilege to the canonical tradition, while silencing Other philosophical voices with the capacity to represent, problematize and experience the world according to other social terms, needs and aspirations. Finally, and as an attempt to overcome the modalities assumed by intellectual colonization in our peripheral educational contexts, it is explored the social and pedagogical relevance of a post-abysmal conception of knowledge.Facultad de Trabajo Socia

Production and characterization of hepatitis B Virus-like Particles expressed in HEK293 and CHO-K1 recombinant cell lines. Analysis of the humoral immune response

Hepatitis B is a life-threatening liver infection caused by the hepatitis B virus (HBV). Even today, HBV infection constitutes a global health problem, affecting more than 250 million people, and vaccination represents the most cost-effective strategy to control HBV spreading. The main antigen of the HBV its the surface antigen (HBsAg), that consists of three co-carboxyterminal envelope glycoproteins, called Large (L), Middle (M), and Small (S). Current available HBV vaccines are based on the non-glycosylated form of the S protein, expressed in yeast cells. Although efficacious and safe, about 10% of people vaccinated with this vaccine fail to mount an adequate antibody response1. One approach to improve HBV vaccination response is increasing immunogenicity via the inclusion of glycosylated S, M and L proteins in hepatitis B virus-like particles (HB-VLPs) expressed in mammalian cells. This new generation vaccine has proven to be able to elicited higher antibody titers breaking the lack of response to the current vaccine. On this regard, domains present in L and M proteins have shown to be more immunostimulatory than the S protein2. Also, the L protein contains the hepatocyte receptor-binding site and is able to induce the production of infection-neutralizing antibodies3. Please click Download on the upper right corner to see the full abstract

Encuentros con la alteridad: hacia modalidades "otras" del trabajo social

El presente trabajo se propone examinar las condiciones de posibilidad para la emergencia de una praxis genuinamente liberadora en el campo del Trabajo Social, bajo la actual coyuntura de avanzada neoliberal. Desde esta perspectiva, en primer lugar adquiere pues relevancia nodal la cuestión de si son acaso posibles prácticas críticas y emancipadoras en dicho contexto o si el planteo mismo no entraña acaso un contrasentido. Siguiendo a Netto, el Trabajo Social “tradicional” no sería más que aquella práctica empirista, reiterativa y burocratizada que los agentes realizan (y realizaron) efectivamente en América Latina, siempre enmarcada dentro de los parámetros de la ética liberal-burguesa y orientada (en clave funcionalista) hacia el objetivo fundamental de corregir los resultados sociales considerados negativos o indeseables (Netto, 1981:44). Sobre esta base, entonces, parece cobrar mayor significación la disyuntiva previamente señalada. Si el/la trabajador/a social se ve obligado/a a presuponer el orden capitalista como un dato factual que no es susceptible de ser eliminado, ¿qué sentido tiene atribuirle a su práctica un potencial transformador del status quo?.Eje Teórico-metodológico en Trabajo Social-GT 28: Práctica filosófica y trabajo social en el contexto neoliberal. Hacia una praxis crítica y emancipadora.Facultad de Trabajo Socia

La descolonización epistemológico-pedagógica será desobediente o no será

En esta presentación tratamos de examinar las condiciones de posibilidad de prácticas pedagógicas liberadoras en el contexto de una educación institucionalizada que permanece bajo la preeminencia del paradigma epistemológico nortecéntrico. El eje central de la ponencia remite a la cuestión de si es posible una praxis pedagógica emancipatoria en dicho escenario o si se trata más bien de un contrasentido. En el abordaje de esta cuestión nodal, la atención está centrada en las “heridas coloniales” que el actual proceso de globalización hegemónica tiende a infligir sobre los actores que intervienen en el campo educativo, concebidos estos como sujetos epistémicos (re)productores y administradores de un saber eurocentrado. Esclarecer las modalidades que asume la colonización intelectual en nuestros contextos académicos/escolares periféricos nos permite explorar, en diálogo con actores institucionales y movimientos sociales, las facetas pedagógicas de una “concepción pos-abismal del saber”.This paper examines the conditions for the possibility of liberating pedagogical practices, in the context of an institutionalized education that remains under the pre-eminence of the Global North epistemological paradigm. The central axis of this article refers to the question of whether an emancipatory pedagogical praxis is possible in this scenario or if it is rather a contradiction. In the approach to this nodal issue, attention is focused on the "colonial wounds" that the current process of hegemonic globalization tends to inflict on the actors involved in the educational field, conceived as epistemic subjects (re) producers and administrators of a eurocentric knowledge. To clarify the modalities assumed by intellectual colonization in our peripheral academic / school contexts allows us to explore, in dialogue with institutional actors and social movements, the pedagogical facets of a "post-abysmal conception of knowledge".Nesta apresentação tentamos examinar as condições de possibilidade das práticas pedagógicas libertadoras no contexto de uma educação institucionalizada que permanece sob o domínio do paradigma epistemológico do Norte Global. O foco deste artigo refere-se à questão de saber se uma prática pedagógica emancipatória em tal cenário é possível ou se é, pelo contrário, uma contradição. Ao abordar este ponto nodal, a atenção está focada nas "feridas coloniais" que o atual processo de globalização hegemônica tende a provocar nos atores envolvidos na educação, concebidos como sujetos epistemológicos (re) produtores e gestores de um conhecimento eurocêntrico. Clarificar as modalidades que assume a colonização intelectual em nossos contextos periféricos acadêmico/de ensino nos permite explorar, em diálogo com os actores institucionais e movimentos sociais, os aspectos educacionais de uma "concepção pós-abissal de conhecimento".Facultad de Trabajo Socia

La descolonización epistemológico-pedagógica será desobediente o no será

En esta presentación tratamos de examinar las condiciones de posibilidad de prácticas pedagógicas liberadoras en el contexto de una educación institucionalizada que permanece bajo la preeminencia del paradigma epistemológico nortecéntrico. El eje central de la ponencia remite a la cuestión de si es posible una praxis pedagógica emancipatoria en dicho escenario o si se trata más bien de un contrasentido. En el abordaje de esta cuestión nodal, la atención está centrada en las “heridas coloniales” que el actual proceso de globalización hegemónica tiende a infligir sobre los actores que intervienen en el campo educativo, concebidos estos como sujetos epistémicos (re)productores y administradores de un saber eurocentrado. Esclarecer las modalidades que asume la colonización intelectual en nuestros contextos académicos/escolares periféricos nos permite explorar, en diálogo con actores institucionales y movimientos sociales, las facetas pedagógicas de una “concepción pos-abismal del saber”.This paper examines the conditions for the possibility of liberating pedagogical practices, in the context of an institutionalized education that remains under the pre-eminence of the Global North epistemological paradigm. The central axis of this article refers to the question of whether an emancipatory pedagogical praxis is possible in this scenario or if it is rather a contradiction. In the approach to this nodal issue, attention is focused on the "colonial wounds" that the current process of hegemonic globalization tends to inflict on the actors involved in the educational field, conceived as epistemic subjects (re) producers and administrators of a eurocentric knowledge. To clarify the modalities assumed by intellectual colonization in our peripheral academic / school contexts allows us to explore, in dialogue with institutional actors and social movements, the pedagogical facets of a "post-abysmal conception of knowledge".Nesta apresentação tentamos examinar as condições de possibilidade das práticas pedagógicas libertadoras no contexto de uma educação institucionalizada que permanece sob o domínio do paradigma epistemológico do Norte Global. O foco deste artigo refere-se à questão de saber se uma prática pedagógica emancipatória em tal cenário é possível ou se é, pelo contrário, uma contradição. Ao abordar este ponto nodal, a atenção está focada nas "feridas coloniais" que o atual processo de globalização hegemônica tende a provocar nos atores envolvidos na educação, concebidos como sujetos epistemológicos (re) produtores e gestores de um conhecimento eurocêntrico. Clarificar as modalidades que assume a colonização intelectual em nossos contextos periféricos acadêmico/de ensino nos permite explorar, em diálogo com os actores institucionais e movimentos sociais, os aspectos educacionais de uma "concepção pós-abissal de conhecimento".Facultad de Trabajo Socia