145 resultados para Grasping


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O presente trabalho tem por objetivo analisar as questões de comunicação na Amazônia. Para isso, procuro discutir os usos sociais que os sujeitos atribuem às diferentes tecnologias envolvidas nesse processo e as relações de poder que se estabelecem nesse ambiente. Para tal exercício, entre os diferentes teóricos que subsidiam essa pesquisa, parto da proposta teórico-metodológica de Jesús Martín-Barbero (2004), que identifica na cartografia uma perspectiva de estudo mais aberta e rigorosa e que possibilita ao pesquisador experienciar as dinâmicas do objeto. Essa vivência seria a chave para apreender a materialidade social, que necessita ser experienciada para, enfim, ser analisada. E, para observar esse cenário contemporâneo, também busco apoio na obra de Henry Jenkins (2012) a fim de entender que a cultura está passando por transformações e as diferentes Tecnologias da Comunicação e Informação (TICs) estão se articulando e proporcionando aos indivíduos uma experiência diferente de interação em sociedade. Contudo, é preciso ter em vista que nem todos participam da mesma forma e, nesse sentido, Michell Foucault (1996; 2008) dá suporte a essa investigação para compreender as questões analíticas do poder em sociedade, a maneira como se manifestam as disputas em pequenas ações e como os indivíduos exercem pequenas formas de dominação entre si. A partir dessas questões é possível afirmar que a Amazônia apresenta um contexto multifacetado, onde as diferenças se inscrevem em cada parte de seu território. Afuá é um exemplo da complexidade que existe na região. Localizada no extremo norte do Arquipélago de Marajó, na Amazônia paraense, a “Veneza do Marajó” (como a cidade é chamada pelos seus moradores) tem suas ruas, casas e construções elevadas sobre palafitas que sustentam a cidade inteira sobre o leito dos rios. Neste lugar particular, a web se popularizou há poucos anos pelo sinal da telefonia móvel e proporcionou um novo cenário de interação entre os seus moradores. Mas é preciso destacar que seu sucesso está fortemente atrelado à importância que as rádios possuem no estabelecimento das relações sociais dessa comunidade. Por esse fenômeno é possível perceber como cada forma de uso das TICs está ligada as experiências que se estabelecem em sociedade. Nesse sentido, pensar a comunicação na Amazônia é um exercício que exige olhar a “natureza comunicativa” dos fenômenos sociais (FRANÇA, 2001), sem perder de vista que esses acontecimentos (FRANÇA, 2012) traduzem contextos específicos, que particularizam o lugar onde se realizam. São esses contextos que possibilitam as práticas de apropriação e os usos sociais diferentes das mídias que estão à disposição dos sujeitos, que tornam a experiência dos indivíduos um acontecimento único e singular e que permitem compreender a amplitude do processo comunicativo, que vai além da simples interação social.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The Contemporary Challenges series - originally sponsored by the Research Deanship of the State University of São Paulo (Unesp) - aims at providing access to essays on crucial issues concerning the Brazilian society as a whole. With the publication of those titles, which systematically avoid unnecessary academic jargon though preserving scientific rigour, the university fulfills one of its essential tasks: that of disseminating the skills and knowledge reared within its quarters. In the present volume, focused upon sociological questions, the authors face the difficult job of grasping the intricate horizon of complexities of Brazilian identity and their presence in the current national dilemmas.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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In the present study we evaluated the relationship between manual preference and intermanual performance asymmetry in reaching of 5-month-old infants. Manual preference was assessed through frequency of reaches toward toys presented at midline, left or right in egocentric coordinates. Intermanual performance asymmetry was evaluated through kinematic analysis. Results showed that performance was predominantly symmetric between hands. Lateral toy positions induced predominance of ipsilateral reaching, while the midline position led to equivalent distribution between right and left handed reaches. No significant correlation between manual preference and intermanual performance asymmetry was observed. These results converge against the notion that manual preference derives from a genetically determined advantage of movement control favoring the right hand. (C) 2012 Elsevier Inc. All rights reserved.

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Nuptial gift offering is a courtship trait found among several insect orders and some spider families. Recent studies indicate that this gift-giving behavior in spiders represents the male mating effort acting on female receptivity through a mechanism of foraging motivation. However, little attention has been given to the sensory channels that are influencing female acceptance. To understand the role of these sensory channels in female perception of a nuptial gift, we focused on the nuptial gift of the neotropical spider Paratrechalea ornata (Araneae, Trechaleidae). The nuptial gift of this species is composed of a prey item wrapped in silk, and previous works suggest that visual and/or chemical cues may be involved in inducing female grasping behavior. We isolated sensory channels using mimetic nuptial gifts (artificial items) or by manipulating real nuptial gifts. Isolated visual signals were not responsible for female acceptance, whereas chemical signals found within the nuptial gift silk layer induced female acceptance. Our findings clearly indicate that a chemical signal located in the silk of the nuptial gift is the main attractant channel, and we formulated 2 hypotheses to explain the mechanisms of action in the female sensory system. We also discuss the consequences of such signaling over female acceptance.

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This study evaluated the functional and quantitative differences between the early and delayed use of phototherapy in crushed median nerves. After a crush injury, low-level laser therapy (GaAs) was applied transcutaneously at the injury site, 3 min daily, with a frequency of five treatments per week for 2 weeks. In the early group, the first laser treatment started immediately after surgery, and in the delayed group, after 7 days. The grasping test was used for functional evaluation of the median nerve, before, 10, and 21 days after surgery, when the rats were killed. Three segments of the median nerve were analyzed histomorphometrically by light microscopy and computer analysis. The following features were observed: myelinated fiber and axon diameters, myelin sheath area, g-ratio, density and number of myelinated fibers, and area and number of capillaries. In the proximal segment (site of crush), the nerves of animals submitted to early and delayed treatment showed myelinated fiber diameter and myelin sheath area significantly larger compared to the untreated group. In the distal segment, the myelin sheath area was significantly smaller in the untreated animals compared to the delayed group. The untreated, early, and delayed groups presented a 50, 57, and 81% degree of functional recovery, respectively, at 21 days after injury, with a significant difference between the untreated and delayed groups. The results suggest that the nerves irradiated with low-power laser exhibit myelinated fibers of greater diameter and a better recovery of function.

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AIM: To investigate the quality of life of patients with HIV and tuberculosis co-infection and grasping the changes imposed in order to live with both transmissible diseases simultaneously. METHODS: Qualitative-quantitative research, undertaken at a specialized outpatient clinic in Fortaleza, Brazil, between 2009 and 2010, involving 34 co-infected patients. For data collection, a quality of life scale called HAT-QoL was used, which consists of 42 items, as well as open questions to perceive the changes the disease causes. RESULTS: Most participants suffered from pulmonary tuberculosis, were male and their education level was low. Quality of life was impaired in those domains related to economic, sexual and secrecy issues. It was also evidenced that the co-infection imposes changes in daily life that underline and further harm quality of life. CONCLUSION: Experiencing co-infection, despite appropriate treatment, causes changes in the patients' lives, whose repercussions can be mitigated through health-promoting interventions.

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Prehension in an act of coordinated reaching and grasping. The reaching component is concerned with bringing the hand to object to be grasped (transport phase); the grasping component refers to the shaping of the hand according to the object features (grasping phase) (Jeannerod, 1981). Reaching and grasping involve different muscles, proximal and distal muscles respectively, and are controlled by different parietofrontal circuit (Jeannerod et al., 1995): a medial circuit, involving area of superior parietal lobule and dorsal premotor area 6 (PMd) (dorsomedial visual stream), is mainly concerned with reaching; a lateral circuit, involving the inferior parietal lobule and ventral premotor area 6 (PMv) (dorsolateral visual stream), with grasping. Area V6A is located in the caudalmost part of the superior parietal lobule, so it belongs to the dorsomedial visual stream; it contains neurons sensitive to visual stimuli (Galletti et al. 1993, 1996, 1999) as well as cells sensitive to the direction of gaze (Galletti et al. 1995) and cells showing saccade-related activity (Nakamura et al. 1999; Kutz et al. 2003). Area V6A contains also arm-reaching neurons likely involved in the control of the direction of the arm during movements towards objects in the peripersonal space (Galletti et al. 1997; Fattori et al. 2001). The present results confirm this finding and demonstrate that during the reach-to-grasp the V6A neurons are also modulated by the orientation of the wrist. Experiments were approved by the Bioethical Committee of the University of Bologna and were performed in accordance with National laws on care and use of laboratory animals and with the European Communities Council Directive of 24th November 1986 (86/609/EEC), recently revised by the Council of Europe guidelines (Appendix A of Convention ETS 123). Experiments were performed in two awake Macaca fascicularis. Each monkey was trained to sit in a primate chair with the head restrained to perform reaching and grasping arm movements in complete darkness while gazing a small fixation point. The object to be grasped was a handle that could have different orientation. We recorded neural activity from 163 neurons of the anterior parietal sulcus; 116/163 (71%) neurons were modulated by the reach-to-grasp task during the execution of the forward movements toward the target (epoch MOV), 111/163 (68%) during the pulling of the handle (epoch HOLD) and 102/163 during the execution of backward movements (epoch M2) (t_test, p ≤ 0.05). About the 45% of the tested cells turned out to be sensitive to the orientation of the handle (one way ANOVA, p ≤ 0.05). To study how the distal components of the movement, such as the hand preshaping during the reaching of the handle, could influence the neuronal discharge, we compared the neuronal activity during the reaching movements towards the same spatial location in reach-to-point and reach-to-grasp tasks. Both tasks required proximal arm movements; only the reach-to-grasp task required distal movements to orient the wrist and to shape the hand to grasp the handle. The 56% of V6A cells showed significant differences in the neural discharge (one way ANOVA, p ≤ 0.05) between the reach-to-point and the reach-to-grasp tasks during MOV, 54% during HOLD and 52% during M2. These data show that reaching and grasping are processed by the same population of neurons, providing evidence that the coordination of reaching and grasping takes place much earlier than previously thought, i.e., in the parieto-occipital cortex. The data here reported are in agreement with results of lesions to the medial posterior parietal cortex in both monkeys and humans, and with recent imaging data in humans, all of them indicating a functional coupling in the control of reaching and grasping by the medial parietofrontal circuit.

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Reaching and grasping an object is an action that can be performed in light, under visual guidance, as well as in darkness, under proprioceptive control only. Area V6A is a visuomotor area involved in the control of reaching movements. V6A, besides neurons activated by the execution of reaching movements, shows passive somatosensory and visual responses. This suggests fro V6A a multimodal capability of integrating sensory and motor-related information, We wanted to know whether this integration occurrs in reaching movements and in the present study we tested whether the visual feedback influenced the reaching activity of V6A neurons. In order to better address this question, we wanted to interpret the neural data in the light of the kinematic of reaching performance. We used an experimental paradigm that could examine V6A responses in two different visual backgrounds, light and dark. In these conditions, the monkey performed an istructed-delay reaching task moving the hand towards different target positions located in the peripersonal space. During the execution of reaching task, the visual feedback is processed in a variety of patterns of modulation, sometimes not expected. In fact, having already demonstrated in V6A reach-related discharges in absence of visual feedback, we expected two types of neural modulation: 1) the addition of light in the environment enhanced reach-related discharges recorded in the dark; 2) the light left the neural response unmodified. Unexpectedly, the results show a complex pattern of modulation that argues against a simple additive interaction between visual and motor-related signals.

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This dissertation presents the synthesis of a hand exoskeleton (HE) for the rehabilitation of post-stroke patients. Through the analysis of state-of-the-art, a topological classification was proposed. Based on the proposed classification principles, the rehabilitation HEs were systematically analyzed and classified. This classification is helpful to both understand the reason of proposing certain solutions for specific applications and provide some useful guidelines for the design of a new HE, that was actually the primary motivation of this study. Further to this classification, a novel rehabilitation HE was designed to support patients in cylindrical shape grasping tasks with the aim of recovering the basic functions of manipulation. The proposed device comprises five planar mechanisms, one per finger, globally actuated by two electric motors. Indeed, the thumb flexion/extension movement is controlled by one actuator whereas a second actuator is devoted to the control of the flexion/extension of the other four fingers. By focusing on the single finger mechanism, intended as the basic model of the targeted HE, the feasibility study of three different 1 DOF mechanisms are analyzed: a 6-link mechanism, that is connected to the human finger only at its tip, an 8-link and a 12-link mechanisms where phalanges and articulations are part of the kinematic chain. The advantages and drawbacks of each mechanism are deeply analyzed with respect to targeted requirements: the 12-link mechanism was selected as the most suitable solution. The dimensional synthesis based on the Burmester theory as well as kinematic and static analyses were separately done for all fingers in order to satisfy the desired specifications. The HE was finally designed and a prototype was built. The experimental results of the first tests are promising and demonstrate the potential for clinical applications of the proposed device in robot-assisted training of the human hand for grasping functions.

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Questo elaborato descrive il lavoro svolto nell'Area ricerca e formazione del Centro Protesi INAIL volto all'integrazione della tecnologia di stampa 3D con i processi produttivi dell'azienda stessa al fine di ottenere una protesi cinematica e funzionale per pazienti con amputazioni parziali di mano (a livello metacarpale e transmetacarpale) che risulti economica e in grado di restituire la funzionalità di grasping della mano.

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Recent research with several species of nonhuman primates suggests sophisticated motor-planning abilities observed in human adults may be ubiquitous among primates. However, there is considerable variability in the extent to which these abilities are expressed across primate species. In the present experiment, we explore whether the variability in the expression of anticipatory motor-planning abilities may be attributed to cognitive differences (such as tool use abilities) or whether they may be due to the consequences of morphological differences (such as being able to deploy a precision grasp). We compared two species of New World monkeys that differ in their tool use abilities and manual dexterity: squirrel monkeys, Saimiri sciureus (less dexterous with little evidence for tool use) and tufted capuchins, Sapajus apella (more dexterous and known tool users). The monkeys were presented with baited cups in an untrained food extraction task. Consistent with the morphological constraint hypothesis, squirrel monkeys frequently showed second-order motor planning by inverting their grasp when picking up an inverted cup, while capuchins frequently deployed canonical upright grasping postures. Findings suggest that the lack of ability for precision grasping may elicit more consistent second-order motor planning, as the squirrel monkeys (and other species that have shown a high rate of second-order planning) have fewer means of compensating for inefficient initial postures. Thus, the interface between morphology and motor planning likely represents an important factor for understanding both the ontogenetic and phylogenetic origins of sophisticated motor-planning abilities.

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Recent research with several species of nonhuman primates suggests sophisticated motor-planning abilities observed in human adults may be ubiquitous among primates. However, there is considerable variability in the extent to which these abilities are expressed across primate species. In the present experiment, we explore whether the variability in the expression of anticipatory motor-planning abilities may be attributed to cognitive differences (such as tool use abilities) or whether they may be due to the consequences of morphological differences (such as being able to deploy a precision grasp). We compared two species of New World monkeys that differ in their tool use abilities and manual dexterity: squirrel monkeys, Saimiri sciureus (less dexterous with little evidence for tool use) and tufted capuchins, Sapajus apella (more dexterous and known tool users). The monkeys were presented with baited cups in an untrained food extraction task. Consistent with the morphological constraint hypothesis, squirrel monkeys frequently showed second-order motor planning by inverting their grasp when picking up an inverted cup, while capuchins frequently deployed canonical upright grasping postures. Findings suggest that the lack of ability for precision grasping may elicit more consistent second-order motor planning, as the squirrel monkeys (and other species that have shown a high rate of second-order planning) have fewer means of compensating for inefficient initial postures. Thus, the interface between morphology and motor planning likely represents an important factor for understanding both the ontogenetic and phylogenetic origins of sophisticated motor-planning abilities. (C) 2013 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.