Effects of gabergic phenols on the dynamic and structure of lipid bilayers: A molecular dynamic simulation approach

γ-Aminobutyric acid (GABA) is the major inhibitory neurotransmitter in the vertebrate and invertebrate nervous system. GABAA receptors are activated by GABA and their agonists, and modulated by a wide variety of recognized drugs, including barbiturates, anesthetics, and benzodiazepines. The phenols propofol, thymol, chlorothymol, carvacrol and eugenol act as positive allosteric modulators on GABAA-R receptor. These GABAergic phenols interact with the lipid membrane, therefore, their anesthetic activity could be the combined result of their specific activity (with receptor proteins) as well as nonspecific interactions (with surrounding lipid molecules) modulating the supramolecular organization of the receptor environment. Therefore, we aimed to contribute to a description of the molecular events that occur at the membrane level as part of the mechanism of general anesthesia, using a molecular dynamic simulation approach. Equilibrium molecular dynamics simulations indicate that the presence of GABAergic phenols in a DPPC bilayer orders lipid acyl chains for carbons near the interface and their effect is not significant at the bilayer center. Phenols interacts with the polar interface of phospholipid bilayer, particularly forming hydrogen bonds with the glycerol and phosphate group. Also, potential of mean force calculations using umbrella sampling show that propofol partition is mainly enthalpic driven at the polar region and entropic driven at the hydrocarbon chains. Finally, potential of mean force indicates that propofol partition into a gel DPPC phase is not favorable. Our in silico results were positively contrasted with previous experimental data.Fil: Miguel, Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; ArgentinaFil: Villarreal, Marcos Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Físico-química de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Investigaciones en Físico-química de Córdoba; ArgentinaFil: Garcia, Daniel Asmed. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones Biológicas y Tecnológicas. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Investigaciones Biológicas y Tecnológicas; Argentin

Diseño de un mecanismo programable para mover un contenedor de productos alimenticios en tres posiciones

Se diseñó la síntesis de un mecanismo tipo Grashoff de 4 barras de tipo seguidor-seguidor, con una diada para controlar y limitar la entrada y salida del movimiento para tres posiciones de exactitud, realizando el análisis cinemático para determinar las características de posición, velocidad y aceleración, tanto para el eslabón de salida, acoplador y eslabón de entrada; así como para un punto acoplador, un punto de entrada y un punto de salida, utilizando el software ―Working Model‖, obteniendo como resultado el movimiento de un contenedor para tres puntos de exactitud en su trayectoria que representan las posiciones deseadas del movimiento y finalmente de controlo a través de un circuito de control electrónico arduino programado para su movimiento automático. Se realizó el prototipo experimental en el que se obtuvieron los resultados esperados

Análisis de deformación en eje de transmisión para un sistema de transferencia automática de estampado

Para determinar si el eje de una transmisión en un sistema mecánico podría trabajar continuamente de manera satisfactoria, se requiere ser analizado por deformación y esfuerzos, en el que, se determinan los valores de mayor magnitud, localización y dirección de lo que se denomina esfuerzos y deformaciones principales. Se analiza la deformación que experimenta el eje a través de la teoría de la curva elástica para comportamiento elástico. Para evaluar los resultados de comportamiento mecánico en el eje de trasmisión, se consideran propuestas de material y de geometría de las diferentes secciones del eje, y desarrollando un programa de cálculo de deformación a través de Excel se determina la variación de esta a través de toda la longitud, además se obtiene como resultado la localización, dirección y magnitud máxima de la deformación en el eje

Análisis y diseño de un molino de bolas de 3.2 TN de 25 HP para reducción de tamaño de 75 a 100 micras

Para diseñar un molino de bolas que trabaje continuamente de manera satisfactoria, se requiere ser analizado por deformación y esfuerzos, en el que, se determinan los valores de mayor magnitud, localización y dirección de lo que se denomina esfuerzos y deformaciones principales. Se analiza el comportamiento de los esfuerzos en cada uno de los componentes a diseñar a través de la teoría de fallas de la energía de la distorsión, esfuerzos de trabajo para comportamiento elástico. Para evaluar los resultados de comportamiento mecánico en estas componentes del molino, se consideran propuestas de material y de geometría de las diferentes partes que lo componen, y desarrollando un programa de análisis y diseño a través de Excel se determina el análisis de esfuerzos en los puntos críticos de las posibles áreas a la falla, la geometría más apropiada para cada una de las componentes, los materiales a utilizar y los factores de seguridad que permiten establecer el trabajo satisfactorio década una de ellas. Además de realizar la selección de las componentes y estimar una cotización de la máquina

Closing the Communication Gap Between Undergraduates and Mathematics Professors

This research sought to determine the sources of communicative difficulties that exist between undergraduate students and international faculty (the communication gap) specifically within the field of mathematics. The hypotheses were as follows: 1) The communication gap results from students\u27 perceptual difficulties in understanding their professors and their own biases against international faculty. 2) The communication gap can be addressed by administering to students a training program that not only provides instruction on accent features, but also attempts to confront accent bias and persuades the student to adopt a more accommodating view of their professors\u27 accents. Fifteen experimental sessions were conducted in October 2009, in order to collect both quantitative data and qualitative data on the communication gap and students\u27 views thereof. Quantitative data was collected through testing sessions that assessed students\u27 baseline performance on mathematics assessments and their performance on one of three assessments after completing either the linguistic training program, a program meant to simulate bias creation, or a control program. Eighty-one undergraduates at the College of William and Mary in Williamsburg, VA, took part in one of six testing sessions. Each assessment was tied to a video lesson taught by a professor from India, and the training program was specifically engineered to address the features of this professor\u27s accent. The variable of interest was each student\u27s improvement in scores between the baseline and post-training assessments, as following from Hypothesis 2, I hypothesized that the students who participated in linguistic training program would produce greater improvement scores than the control group. I also hypothesized, on the basis of Hypothesis 1, that students who participated in the bias program would produce significantly worse improvement scores than the control group. An analysis of the data resulting from the testing sessions revealed no significant difference in improvement scores arising from membership in one of these three testing groups. Qualitative data was collected through discussion sessions with testing session participants two weeks after the testing sessions and through questionnaires administered at the end of the testing sessions. Fifty-seven undergraduates from the original sample of 81 participated in discussion sessions. The discussion sessions addressed issues surrounding the communication gap, including classes with international professors, frustrations with communication breakdown, and suggestions for solutions to the communication gap. Data from these sessions were analyzed using an ethnographic approach, revealing substantial cross-group trends and themes. While students did not universally embrace the idea that they contributed to the communication gap and so bore responsibility for closing it, almost all agreed that further research on the issue was vital. A quantitative analysis of response data on the post-testing questionnaire revealed a significant effect of linguistic training on linguistic attitudes. Therefore, although it was not reflected in assessment scores, the use of linguistic training did have a positive effect on students. Further research in this area is vital to determine a reliable application of this result to greater professor-student communication

How Black Does Obama Sound Now?: Testing Listener Judgments of Intonation in Incrementally Manipulated Speech

Recent research in perceptual sociolinguistics has investigated a host of variables—primarily segmental—to assess the extent to which social meanings are constructed in perception similarly to the way they are constructed in ongoing production. Despite production research in sociolinguistics that has demonstrated how speakers use intonational variation to index various ethnic identities and social stances (Burdin 2015, Holliday 2016, Reed 2016), there has been a general lack of perceptual research on the social meanings of intonational variables. At the same time, research in perceptual sociolinguistics has not confronted the issue of whether social meanings are incremental—that is, does a more phonetically extreme token of a socially marked variable correspond to a stronger social meaning? We address these gaps in research by testing listener judgments of manipulations of Barack Obama\u27s utterances in one interview. In this perceptual task, critical stimuli were declarative Intonational Phrases with H* and/or L+H* pitch accents (Beckman et al. 2007) that were manipulated to four manipulation steps, with successively more extreme F0 maxima and minima with each step. Ninety-three American English listeners rated 80 critical stimuli and 40 filler stimuli (excerpted from the same interview of Obama) on the question, How Black does Obama sound here? , using a slider bar. A mixed-effects regression model was conducted for listener ratings of blackness by assessing the interaction of Phrase Type (H* only vs. L+H*) and Manipulation Step. Listeners perceived stimuli with at least one L+H* token as sounding more black than those without, but only for phrases with more phonetically extreme realizations of the L+H* contour. These results demonstrate that listeners are sensitive to stepwise manipulations of the F0 contour, indicating that incrementality affects social meanings of intonational variables and providing a promising new direction for studies on listener judgments of ethnicity

Overlearning speaker race in sociolinguistic auto-coding

Concerns about AI fairness have been raised in domains like the American criminal justice system, where algorithms assessing the risk of a pretrial defendant may inadvertently use defendants’ race as a decision criterion. Similar risks apply to the domain of sociolinguistic auto-coding, in which machine learning classifiers assign categories to variable data based on acoustic features (e.g., car vs “cah”). The proposed project addresses this possibility by using sociolinguistic data by assessing the extent to which auto-coders fail to perform equally well on Black vs White speakers of New England English. We will first assess how an auto-coding classifier that does not take any fairness conditions into account performs with respect to fairness as we have defined it. We will then assess remedies that have been suggested in recent work on AI fairness. Contrary to the approach where AI fairness is an afterthought, the proposed project introduces the notion of AI fairness to a new algorithm in the algorithm’s infancy, rather than after it has been widely adopted

Obtención del módulo de elasticidad y razón de Poisson en diferentes grados de acero al silicio

Tesis (Maestría en Ciencias de la Ingeniería Mecánica con Especialidad en Materiales) - U.A.N.L, 2000UANLhttp://www.uanl.mx

Brave New GES World:A Systematic Literature Review of Gestures and Referents in Gesture Elicitation Studies

How to determine highly effective and intuitive gesture sets for interactive systems tailored to end users’ preferences? A substantial body of knowledge is available on this topic, among which gesture elicitation studies stand out distinctively. In these studies, end users are invited to propose gestures for specific referents, which are the functions to control for an interactive system. The vast majority of gesture elicitation studies conclude with a consensus gesture set identified following a process of consensus or agreement analysis. However, the information about specific gesture sets determined for specific applications is scattered across a wide landscape of disconnected scientific publications, which poses challenges to researchers and practitioners to effectively harness this body of knowledge. To address this challenge, we conducted a systematic literature review and examined a corpus of N=267 studies encompassing a total of 187, 265 gestures elicited from 6, 659 participants for 4, 106 referents. To understand similarities in users’ gesture preferences within this extensive dataset, we analyzed a sample of 2, 304 gestures extracted from the studies identified in our literature review. Our approach consisted of (i) identifying the context of use represented by end users, devices, platforms, and gesture sensing technology, (ii) categorizing the referents, (iii) classifying the gestures elicited for those referents, and (iv) cataloging the gestures based on their representation and implementation modalities. Drawing from the findings of this review, we propose guidelines for conducting future end-user gesture elicitation studies