Nous sommes tousjours au dela : a negação narrative do sujeito modern em Sur des vers de Virgile (ensaios III, cap.V) de Michel de Motaigne

Investigando a apresentação das ideias em Sobre versos de Virgílio, a tese demonstra como sua estruturação ambígua, onde tudo é constantemente negado por seus contrários, leva a um contínuo estado de confusão e perplexidade, tornando impossível a determinação lógica dos conceitos e conduzindo a um progressivo esvaziamento do texto enquanto signo direto do pensamento do autor. Por outro lado, partindo de uma perspectiva hermenêutica influenciada pela anatomia, a análise mostra que o uso sistemático e criativo das instâncias narrativas (autor, narrador, signatário), juntamente com a reunificação textual de diferentes Montaignes (presentes nos diversos estágio editoriais do ensaio), acaba por dissolver a própria noção de identidade a si do autor, tendo por consequência imediata sua disseminação em vários sujeitos diversos e contraditórios e, por fim, colocando em xeque a clássica percepção dos Ensaios com o nascimento da subjetividade moderna.

Near optimal combination of sensory and motor uncertainty in time during a naturalistic perception-action task.

Most behavioral tasks have time constraints for successful completion, such as catching a ball in flight. Many of these tasks require trading off the time allocated to perception and action, especially when only one of the two is possible at any time. In general, the longer we perceive, the smaller the uncertainty in perceptual estimates. However, a longer perception phase leaves less time for action, which results in less precise movements. Here we examine subjects catching a virtual ball. Critically, as soon as subjects began to move, the ball became invisible. We study how subjects trade-off sensory and movement uncertainty by deciding when to initiate their actions. We formulate this task in a probabilistic framework and show that subjects' decisions when to start moving are statistically near optimal given their individual sensory and motor uncertainties. Moreover, we accurately predict individual subject's task performance. Thus we show that subjects in a natural task are quantitatively aware of how sensory and motor variability depend on time and act so as to minimize overall task variability.

Human muscle spindles act as forward sensory models.

Modern theories of motor control incorporate forward models that combine sensory information and motor commands to predict future sensory states. Such models circumvent unavoidable neural delays associated with on-line feedback control. Here we show that signals in human muscle spindle afferents during unconstrained wrist and finger movements predict future kinematic states of their parent muscle. Specifically, we show that the discharges of type Ia afferents are best correlated with the velocity of length changes in their parent muscles approximately 100-160 ms in the future and that their discharges vary depending on motor sequences in a way that cannot be explained by the state of their parent muscle alone. We therefore conclude that muscle spindles can act as "forward sensory models": they are affected both by the current state of their parent muscle and by efferent (fusimotor) control, and their discharges represent future kinematic states. If this conjecture is correct, then sensorimotor learning implies learning how to control not only the skeletal muscles but also the fusimotor system.

Adaptive evolution of MRGX2, a human sensory neuron specific gene involved in nociception

MRGX2, a G-protein-coupled receptor, is specifically expressed in the sensory neurons of the human peripheral nervous system and involved in nociception. Here, we studied DNA polymorphism patterns and evolution of the MRGX2 gene in world-wide human populations and the representative nonhuman primate species. Our results demonstrated that MRGX2 had undergone adaptive changes in the path of human evolution, which were likely caused by Darwinian positive selection. The patterns of DNA sequence polymorphisms in human populations showed an excess of derived substitutions, which against the expectation of neutral evolution, implying that the adaptive evolution of MRGX2 in humans was a relatively recent event. The reconstructed secondary structure of the human MRGX2 revealed that three of the four human-specific amino acid substitutions were located in the extra-cellular domains. Such critical substitutions may alter the interactions between MRGX2 protein and its ligand, thus, potentially led to adaptive changes of the pain-perception-related nervous system during human evolution. (c) 2005 Elsevier B.V. All rights reserved.

Methods of sensory evaluation of quality and application of statistical methods in sensory evaluation problems with special reference to fishery products

The quality of raw and processed fishery products depend on several factors like physiological conditions at the time of capture, morphological differences, rigor mortis, species, rate of icing and subsequent storage conditions. Sensory evaluation is still the most reliable method for evaluation of the freshness of raw processed fishery products. Sophisticated methods like Intelectron fish tester, cell fragility technique and chemical and bacteriological methods like estimation of trimethylamine, hypoxanthine, carbonyl compounds, volatile acid and total bacterial count have no doubt been developed for accessing the spoilage in fish products.

Some further considerations in the development of an experimental design for sensory evaluation of fish quality

An experimental procedure along with a method of analysis to judge the suitability of an individual to be included in a taste panel is described. The procedure is based on comparison of the organoleptic scores assigned by the individual to pairs of fish samples whose qualities are known and a set of physical measurements of the same samples. Fisher's Exact Probability Test provides a criterion for the judgement.

Comparison of sensory characteristics and biochemical parameters in commercial frozen prawns

Commercial samples of frozen shrimp of different styles of presentation and size grades were tested for sensory, physical (cooked yield and pH) and biochemical characteristics (moisture, total nitrogen, water extractable nitrogen, nonprotein nitrogen, alpha amino nitrogen, total volatile nitrogen and trimethylamine nitrogen). The test results are compared and correlated. The order of preference of the samples were HL>PUD>P & D. There was significant correlation between sensory score of cooked sample and WEN, NPN and ∞ – NHsub(2)-N values. TVN and TMA-N did not exhibit any correlation with sensory score. It is inferred that in quality measurement of frozen shrimps of commerce the quantity of water soluble components and the total dry matter can be used to support the sensory test results.

Learning feedforward commands to muscles using time-shifted sensory feedback

In adapting to changing forces in the mechanical environment, humans change the force being applied by the limb by reciprocal changes in the activation of antagonistic muscles. However, they also cocontract these muscles when interaction with the environment is mechanically unstable to increase the mechanical impedance of the limb. We have postulated that appropriate patterns of muscle activation could be learned using a simple scheme in which the naturally occurring stretch reflex is used as a template to adjust feedforward commands to muscles. Feedforward commands are modified iteratively by shifting a scaled version of the reflex response forward in time and adding it to the previous feedforward command. We show that such an algorithm can account for the principal features of changes in muscle activation observed when human subjects adapt to instabilities in the mechanical environment. © 2006.