982 resultados para expressions figées
Variable mixed-mode delamination in composite laminates under fatigue conditions: testing & analysis
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La majoria de les fallades en elements estructurals sn degudes a crrega per fatiga. En conseqncia, la fatiga mecnica s un factor clau per al disseny d'elements mecnics. En el cas de materials compsits laminats, el procs de fallada per fatiga inclou diferents mecanismes de dany que resulten en la degradaci del material. Un dels mecanismes de dany ms importants s la delaminaci entre capes del laminat. En el cas de components aeronutics, les plaques de composit estan exposades a impactes i les delaminacions apareixen facilment en un laminat desprs d'un impacte. Molts components fets de compsit tenen formes corbes, superposici de capes i capes amb diferents orientacions que fan que la delaminaci es propagui en un mode mixt que depen de la grandria de la delaminaci. s a dir, les delaminacions generalment es propaguen en mode mixt variable. s per aix que s important desenvolupar nous mtodes per caracteritzar el creixement subcrtic en mode mixt per fatiga de les delaminacions. El principal objectiu d'aquest treball s la caracteritzaci del creixement en mode mixt variable de les delaminacions en compsits laminats per efecte de crregues a fatiga. Amb aquest fi, es proposa un nou model per al creixement per fatiga de la delaminaci en mode mixt. Contrriament als models ja existents, el model que es proposa es formula d'acord a la variaci no-monotnica dels parmetres de propagaci amb el mode mixt observada en diferents resultats experimentals. A ms, es du a terme un anlisi de l'assaig mixed-mode end load split (MMELS), la caracterstica ms important del qual s la variaci del mode mixt a mesura que la delaminaci creix. Per a aquest anlisi, es tenen em compte dos mtodes terics presents en la literatura. No obstant, les expressions resultants per l'assaig MMELS no sn equivalents i les diferncies entre els dos mtodes poden ser importants, fins a 50 vegades. Per aquest motiu, en aquest treball es porta a terme un anlisi alternatiu ms acurat del MMELS per tal d'establir una comparaci. Aquest anlisi alternatiu es basa en el mtode dels elements finits i virtual crack closure technique (VCCT). D'aquest anlisi en resulten importants aspectes a considerar per a la bona caracteritzaci de materials utilitzant l'assaig MMELS. Durant l'estudi s'ha dissenyat i construt un utillatge per l'assaig MMELS. Per a la caracteritzaci experimental de la propagaci per fatiga de delaminacions en mode mixt variable s'utilitzen diferents provetes de laminats carboni/epoxy essencialment unidireccionals. Tamb es du a terme un anlisi fractogrfic d'algunes de les superfcies de fractura per delaminaci. Els resultats experimentals sn comparats amb les prediccions del model proposat per la propagaci per fatiga d'esquerdes interlaminars.
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El coneixement de la superfcie d'energia potencial (PES) ha estat essencial en el mn de la qumica terica per tal de discutir tant la reactivitat qumica com l'estructura i l'espectroscpia molecular. En el camp de la reactivitat qumica es hem proposat continuar amb el desenvolupament de nova metodologia dins el marc de la teoria del funcional de la densitat conceptual. En particular aquesta tesis es centrar en els segents punts: a) El nombre i la naturalesa dels seus punts estacionaris del PES poden sofrir canvis radicals modificant el nivell de clcul utilitzats, de tal manera que per estar segurs de la seva naturalesa cal anar a nivells de clcul molt elevats. La duresa s una mesura de la resistncia d'un sistema qumic a canviar la seva configuraci electrnica, i segons el principi de mxima duresa on hi hagi un mnim o un mxim d'energia trobarem un mxim o un mnim de duresa, respectivament. A l'escollir tot un conjunt de reaccions problemtiques des del punt de vista de presncia de punts estacionaris erronis, hem observat que els perfils de duresa sn ms independents de la base i del mtode utilitzats, a ms a ms sempre presenten el perfil correcte. b) Hem desenvolupat noves expressions basades en les integracions dels kernels de duresa per tal de determinar la duresa global d'una molcula de manera ms precisa que la utilitzada habitualment que est basada en el clcul numric de la derivada segona de l'energia respecte al nmero d'electrons. c) Hem estudiat la validesa del principis de mxima duresa i de mnima polaritzabiliat en les vibracions asimtriques en sistemes aromtics. Hem trobat que per aquests sistemes alguns modes vibracionals incompleixen aquests principis i hem analitzat la relaci d'aquest l'incompliment amb l'efecte de l'acoblament pseudo-Jahn-Teller. A ms a ms, hem postulat tot un conjunt de regles molt senzilles que ens permetien deduir si una molcula compliria o no aquests principis sense la realitzaci de cap clcul previ. Tota aquesta informaci ha estat essencial per poder determinar exactament quines sn les causes del compliment o l'incompliment del MHP i MPP. d) Finalment, hem realitzat una expansi de l'energia funcional en termes del nombre d'electrons i de les coordenades normals dintre del conjunt cannic. En la comparaci d'aquesta expansi amb l'expansi de l'energia del nombre d'electrons i del potencial extern hem pogut recuperar d'una altra forma diferent tot un conjunt de relacions ja conegudes entre alguns coneguts descriptors de reactivitat del funcional de la densitat i en poden establir tot un conjunt de noves relacions i de nous descriptors. Dins del marc de les propietats moleculars es proposa generalitzar i millorar la metodologia pel clcul de la contribuci vibracional (Pvib) a les propietats ptiques no lineals (NLO). Tot i que la Pvib no s'ha tingut en compte en la majoria dels estudis terics publicats de les propietats NLO, recentment s'ha comprovat que la Pvib de diversos polmers orgnics amb altes propietats ptiques no lineals s fins i tot ms gran que la contribuci electrnica. Per tant, tenir en compte la Pvib s essencial en el disseny dels nous materials ptics no lineals utilitzats en el camp de la informtica, les telecomunicacions i la tecnologia lser. Les principals lnies d'aquesta tesis sobre aquest tema sn: a) Hem calculat per primera vegada els termes d'alt ordre de Pvib de diversos polmers orgnics amb l'objectiu d'avaluar la seva importncia i la convergncia de les sries de Taylor que defineixen aquestes contribucions vibracionals. b) Hem avaluat les contribucions electrniques i vibracionals per una srie de molcules orgniques representatives utilitzant diferents metodologies, per tal de poder de determinar quina s la manera ms senzilla per poder calcular les propietats NLO amb una precisi semiquantitativa.
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Em finais da dcada de sessenta, um grupo de investigadores descobriu que para um conjunto de emoes bsicas existem expresses no-verbais distintas, universais, e provavelmente inatas. Desde ento, multiplicaram-se os estudos em diferentes culturas que pretendem testar a tese da universalidade. Muitos deles consistiram no desenvolvimento e validao de sistemas de codificao de aco muscular facial para as expresses das diferentes emoes. Recentemente, tm surgido evidncias de universalidade das expresses de algumas emoes auto-conscientes. Esta investigao teve como objectivo testar o comportamento na populao portuguesa do University of California, Davis, Set of Emotion Expressions, ou UCDSEE (Tracy, Robins, & Schriber, 2009), um conjunto de 47 fotografias com expresses emocionais bsicas e auto-conscientes. Participaram nesta investigao 427 estudantes universitrios, a quem foi pedido que as observassem e identificassem as respectivas emoes. As expresses das emoes em estudo foram reconhecidas pela populao portuguesa num nvel superior ao acaso, exceptuando as de vergonha. O reconhecimento das expresses das emoes bsicas foi superior ao das emoes auto- conscientes. O UCDSEE mostrou-se adequado para futuros estudos com a populao portuguesa.
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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.
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The effect of multiple sclerosis (MS) on the ability to identify emotional expressions in faces was investigated, and possible associations with patients characteristics were explored. 56 non-demented MS patients and 56 healthy subjects (HS) with similar demographic characteristics performed an emotion recognition task (ERT), the Benton Facial Recognition Test (BFRT), and answered the Hospital Anxiety and Depression Scale (HADS). Additionally, MS patients underwent a neurological examination and a comprehensive neuropsychological evaluation. The ERT consisted of 42 pictures of faces (depicting anger, disgust, fear, happiness, sadness, surprise and neutral expressions) from the NimStim set. An iViewX high-speed eye tracker was used to record eye movements during ERT. The fixation times were calculated for two regions of interest (i.e., eyes and rest of the face). No significant differences were found between MS and HC on ERTs behavioral and oculomotor measures. Bivariate and multiple regression analyses revealed significant associations between ERTs behavioral performance and demographic, clinical, psychopathological, and cognitive measures.
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RESUMO: Objetivo - apresentar o contributo da Escola Me Hilda para a afirmao da identidade afro-brasileira na populao estudantil da Cidade do Salvador. Especificamente: a) conhecer os fundamentos pedaggicos-curricular da Escola Me Hilda; b) analisar os materiais didticos utilizados pela Escola Me Hilda; c) apresentar as metodologias de trabalho da Escola Me Hilda. Metodologia - quanto ao percurso metodolgico, em razo da questo bsica desta dissertao, optou-se por realizar pesquisa qualitativa de natureza etnogrfica, envolvendo uma abordagem emprica voltada para a abordagem de distrbios identitrios, em suas diversas dimenses na auto-estima de afro-descendentes. Foram estudados aspectos que envolvem o currculo, a sala de aula e atividades a que esto expostas as crianas da Escola Me Hilda. Resultados - examinando- se os contedos dos Cadernos de Educao do Il Aiy como proposta pedaggica da Escola Me Hilda, observou- se que seus fudamentos do ressignificao aos alunos, em termos de superao de distrbios identitrios, isto , proporcionar o desenvolvimento e construo da identidade negra naqueles afro-descendentes, devido valorizao esttica do universo cultural africano e afro-brasileiro, reconhecendo a frica como uma das matrizes legtimas da cultura humana, em geral, e da brasileira, em particular. Concluso- a pedagogia da (re) construo da identidade negra na Escola Me Hilda pode contribuir para a desconstruo dos distrbios identitrios; sendo assim, recomendada para escolas em Salvador-Bahia e em outras regies do Brasil. ABSTRACT: Objective- study Escola Me Hilda (EMH - Mother Hilda School) contribution to the affirmation of an African-Brazilian identity in Bahias black student population. In particular: a) understand EMHs pedagogical and curricula core; b) analyze teaching materials used at EMH; c) show EMHs work methodology. Methodology- due to the very nature of this dissertations basic inquiry, ethnography in nature qualitative research targeted at identity disturbances in its various dimensions regarding African descendents self-esteem was performed. Aspects regarding EMH curriculum and classroom activities were studied. The choice of ethnography as an observation tool followed empirical analysis of whether Il Aiys Educational Booklets as adopted by EMH aids students with identity disturbances and how it promotes the development of a black identity in those black descendants. Results- it has been observed that EMH utilizes methodological and pedagogical resources such as: story-telling, written reports, images, objects, dances, music, letters, myths, gestures, legends, craftsmanship, and clothing as vehicles to re-assign students self esteem, as well as, build their critical and self-aware knowledge of black descendants identity. Conclusion.- EMH pedagogical work, by encompassing various types of cultural and artistic expressions, as detailed in the aforementioned booklets, values African and Brazilian-African references. This aesthetic valuation therefore promotes an identity ressignification and the reintegration of the black descendent since it works within the symbolic and cultural universe of the African and African-Brazilian culture recognizing Africa as a legitimate matrix of human culture, in general, and of Brazilian in particular. Conclusively, EMH black identity (re)construction pedagogy can contribute to deconstruct identity disturbances; and as such, can be recommended to be adopted at other schools in Salvador, Bahia and other regions in Brazil.
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Apesar dos evidentes progressos nesta rea, a fora tem sido uma das capacidades motoras mais controversas e questionadas, no que diz respeito ao seu desenvolvimento em contexto escolar. O objectivo principal deste estudo consistiu em verificar as probabilidades de aumentar o rendimento na fora em crianas e jovens, com idades compreendidas entre os 12 e os 14 anos, atravs da aplicao de um programa de treino especfico de fora nas condies particulares da aula de Educao Fsica. Para atingir este objectivo foi analisada uma amostra populacional de 181 alunos da Escola Secundria Braamcamp Freire, em Lisboa, sendo dividida em 2 grupos de trabalho: um grupo foi submetido ao programa especfico de fora, enquanto o outro realizou, em simultneo, uma tarefa de corrida contnua volta do espao de aula. O protocolo dos programas especficos de treino teve a durao de 26 semanas, com uma unidade semanal de treino, utilizando apenas meios existentes na escola. A recolha dos dados foi realizada em 3 momentos de avaliao e todos os alunos foram sujeitos aos mesmos testes (Extenso de Braos, Abdominais, Extenso do Tronco, Impulso Horizontal e Vaivm). Os dados foram tratados utilizando a ferramenta estatsitca Software SPSS. A anlise estatstica demonstrou pelo estudo da percentagem de evoluo e pelo teste t de Student que o programa especfico de fora aplicado permitiu uma maior evoluo no desenvolvimento das diferentes expresses de fora, comparativamente com os alunos que no foram submetidos a este programa. No que diz respeito evoluo da fora em funo do gnero, atravs da anlise comparada das mdias de testes, verificou-se que o sexo masculino apresentou melhores resultados. Desta forma, podemos concluir que o programa especfico de fora foi eficaz, na medida em que os alunos de ambos os sexos pertencentes a este grupo de trabalho apresentaram ganhos significativos em todos os testes.
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O conceito de Psicanlise Aplicada foi fabricado por Lacan para dar nome A prtica psicanaltica nas modernas Instituies de Sade Mental. Esta comunicao apresenta o caso de um esquizofrnico que ocultou aos psiquiatras o contedo do seu delrio, at que foi tratado por um analista. No usou o saber cientfico (neurolpticos, etc.), mas escutando o duplo sentido dos seus ditos e lendo os seus escritos sob transferncia:
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El ensayo analiza la visin que la historiografa tradicional ha consolidado sobre la participacin popular en la Independencia de Colombia y explora los temas que la ms reciente historiografa sobre este perodo ha cuestionado y renovado. Entre dichos temas se encuentran: las guerras de independencia como expresin de conflictos preexistentes, la reduccin de los trminos del enfrentamiento nicamente a los bandos republicano y realista, el recurso al pueblo como mecanismo de presin y legitimidad, la reelaboracin del discurso republicano entre los sectores populares, y la movilizacin indgena antirrepublicana. El artculo concluye presentando algunas propuestas que enriqueceran la comprensin de la poltica popular desplegada a lo largo de las guerras de independencia.
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The literature on vertical disparity is complicated by the fact that several different definitions of the term vertical disparity are in common use, often without a clear statement about which is intended or a widespread appreciation of the properties of the different definitions. Here, we examine two definitions of retinal vertical disparity: elevation-latitude and elevation-longitude disparities. Near the fixation point, these definitions become equivalent, but in general, they have quite different dependences on object distance and binocular eye posture, which have not previously been spelt out. We present analytical approximations for each type of vertical disparity, valid for more general conditions than previous derivations in the literature: we do not restrict ourselves to objects near the fixation point or near the plane of regard, and we allow for non-zero torsion, cyclovergence, and vertical misalignments of the eyes. We use these expressions to derive estimates of the latitude and longitude vertical disparities expected at each point in the visual field, averaged over all natural viewing. Finally, we present analytical expressions showing how binocular eye positiongaze direction, convergence, torsion, cyclovergence, and vertical misalignmentcan be derived from the vertical disparity field and its derivatives at the fovea.
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Here we show inverse fMRI activation patterns in amygdala and medial prefrontal cortex (mPFC) depending upon whether subjects interpreted surprised facial expressions positively or negatively. More negative interpretations of surprised faces were associated with greater signal changes in the right ventral amygdala, while more positive interpretations were associated with greater signal changes in the ventral mPFC. Accordingly, signal change within these two areas was inversely correlated. Thus, individual differences in the judgment of surprised faces are related to a systematic inverse relationship between amygdala and mPFC activity, a circuitry that the animal literature suggests is critical to the assessment of stimuli that predict potential positive vs negative outcomes.
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We recently demonstrated a functional relationship between fMRI responses within the amygdala and the medial prefrontal cortex based upon whether subjects interpreted surprised facial expressions positively or negatively. In the present fMRI study, we sought to assess amygdala-medial prefrontal cortex responsivity when the interpretations of surprised faces were determined by contextual experimental stimuli, rather than subjective judgment. Subjects passively viewed individual presentations of surprised faces preceded by either a negatively or positively valenced contextual sentence (e. g., She just found $500 vs. She just lost $500). Negative and positive sentences were carefully matched in terms of length, situations described, and arousal level. Negatively cued surprised faces produced greater ventral amygdala activation compared to positively cued surprised faces. Responses to negative versus positive sentences were greater within the ventrolateral prefrontal cortex, whereas responses to positive versus negative sentences were greater within the ventromedial prefrontal cortex. The present study demonstrates that amygdala response to surprised facial expressions can be modulated by negatively versus positively valenced verbal contextual information. Connectivity analyses identified candidate cortical-subcortical systems subserving this modulation.
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BACKGROUND: Previous functional imaging studies demonstrating amygdala response to happy facial expressions have all included the presentation of negatively valenced primary comparison expressions within the experimental context. This study assessed amygdala response to happy and neutral facial expressions in an experimental paradigm devoid of primary negatively valenced comparison expressions. METHODS: Sixteen human subjects (eight female) viewed 16-sec blocks of alternating happy and neutral faces interleaved with a baseline fixation condition during two functional magnetic resonance imaging scans. RESULTS: Within the ventral amygdala, a negative correlation between happy versus neutral signal changes and state anxiety was observed. The majority of the variability associated with this effect was explained by a positive relationship between state anxiety and signal change to neutral faces. CONCLUSIONS: Interpretation of amygdala responses to facial expressions of emotion will be influenced by considering the contribution of each constituent condition within a greater subtractive finding, as well as 1) their spatial location within the amygdaloid complex; and 2) the experimental context in which they were observed. Here, an observed relationship between state anxiety and ventral amygdala response to happy versus neutral faces was explained by response to neutral faces.
