1000 resultados para Función mental
Resumo:
The objective of the present survey was to assess the Brazilian scientific production in psychiatry, psychobiology, and mental health during the 1998-2002 period. The universities' graduate programs concentrate the vast majority of the scientific production in Brazil. We assessed the annual reports from the graduate programs to the Brazilian Ministry of Education concerning master's and doctoral theses and the articles published in journals indexed by the Institute of Scientific Information (ISI). There are nine Master's and Doctoral graduate programs dedicated to research in psychiatry, neuropsychiatry, psychobiology, and mental health in the country, seven being located in southern states. During the 5-year period, from 1998 to 2002, 186 students received their doctorate degree (37/year). The programs published 637 articles in journals indexed by ISI, the majority of them in journals with an impact factor higher than 2. The research advisors' productivity varied among graduate programs, ranging from 0.6 to 2.0 articles per year in ISI-indexed journals. Despite the substantial barriers faced by the Brazilian scientific community (mainly financial and writing difficulties), Brazil's scientific mental health production is on the rise. The number of articles published in ISI-indexed journals has doubled without a significant increase in the number of graduate theses, suggesting that there was an improvement in both the quality of the scientific production and the productivity of the graduate programs. Based on these data, it is reasonable to predict a tendency to an increase in production over the next few years.
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A clinical study of Brazilian patients with neurofibromatosis type 1 (NF1) was performed in a multidisciplinary Neurofibromatosis Program called CEPAN (Center of Research and Service in Neurofibromatosis). Among 55 patients (60% females, 40% males) who met the NIH criteria for the diagnosis of NF1, 98% had more than six café-au-lait patches, 94.5% had axillary freckling, 45% had inguinal freckling, and 87.5% had Lisch nodules. Cutaneous neurofibromas were observed in 96%, and 40% presented plexiform neurofibromas. A positive family history of NF1 was found in 60%, and mental retardation occurred in 35%. Some degree of scoliosis was noted in 49%, 51% had macrocephaly, 40% had short stature, 76% had learning difficulties, and 2% had optic gliomas. Unexpectedly high frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis were observed, probably reflecting the detailed clinical analysis methods adopted by the Neurofibromatosis Program. These same patients were screened for mutations in the GAP-related domain/GRD (exons 20-27a) by single-strand conformation polymorphism. Four different mutations (Q1189X, 3525-3526delAA, E1356G, c.4111-1G>A) and four polymorphisms (c.3315-27G>A, V1146I, V1317A, c.4514+11C>G) were identified. These data were recently published.
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Since neurovascular control is altered in obese subjects, we hypothesized that weight loss by diet (D) or diet plus exercise training (D + ET) would improve neurovascular control during mental stress in obese women. In a study with a dietary reduction of 600 kcal/day with or without exercise training for 4 months, 53 obese women were subdivided in D (N = 22, 33 ± 1 years, BMI 34 ± 1 kg/m²), D + ET (N = 22, 33 ± 1 years, BMI 33 ± 1 kg/m²), and nonadherent (NA, N = 9, 35 ± 2 years, BMI 33 ± 1 kg/m²) groups. Muscle sympathetic nerve activity (MSNA) was measured by microneurography and forearm blood flow by venous occlusion plethysmography. Mental stress was elicited by a 3-min Stroop color word test. Weight loss was similar between D and D + ET groups (87 ± 2 vs 79 ± 2 and 85 ± 2 vs 76 ± 2 kg, respectively, P < 0.05) with a significant reduction in MSNA during mental stress (58 ± 2 vs 50 ± 2, P = 0.0001, and 59 ± 3 vs 50 ± 2 bursts/100 beats, P = 0.0001, respectively), although the magnitude of the response was unchanged. Forearm vascular conductance during mental stress was significantly increased only in D + ET (2.74 ± 0.22 vs 3.52 ± 0.19 units, P = 0.02). Weight loss reduces MSNA during mental stress in obese women. The increase in forearm vascular conductance after weight loss provides convincing evidence for D + ET interventions as a nonpharmacologic therapy of human obesity.
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It has been shown that mental rotation of objects and human body parts is processed differently in the human brain. But what about body parts belonging to other primates? Does our brain process this information like any other object or does it instead maximize the structural similarities with our homologous body parts? We tried to answer this question by measuring the manual reaction time (MRT) of human participants discriminating the handedness of drawings representing the hands of four anthropoid primates (orangutan, chimpanzee, gorilla, and human). Twenty-four right-handed volunteers (13 males and 11 females) were instructed to judge the handedness of a hand drawing in palm view by pressing a left/right key. The orientation of hand drawings varied from 0º (fingers upwards) to 90º lateral (fingers pointing away from the midline), 180º (fingers downwards) and 90º medial (finger towards the midline). The results showed an effect of rotation angle (F(3, 69) = 19.57, P < 0.001), but not of hand identity, on MRTs. Moreover, for all hand drawings, a medial rotation elicited shorter MRTs than a lateral rotation (960 and 1169 ms, respectively, P < 0.05). This result has been previously observed for drawings of the human hand and related to biomechanical constraints of movement performance. Our findings indicate that anthropoid hands are essentially equivalent stimuli for handedness recognition. Since the task involves mentally simulating the posture and rotation of the hands, we wondered if "mirror neurons" could be involved in establishing the motor equivalence between the stimuli and the participants' own hands.
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To determine the hemodynamic mechanisms responsible for the attenuated blood pressure response to mental stress after exercise, 26 healthy sedentary individuals (age 29 ± 8 years) underwent the Stroop color-word test before and 60 min after a bout of maximal dynamic exercise on a treadmill. A subgroup (N = 11) underwent a time-control experiment without exercise. Blood pressure was continuously and noninvasively recorded by infrared finger photoplethysmography. Stroke volume was derived from pressure signals, and cardiac output and peripheral vascular resistance were calculated. Perceived mental stress scores were comparable between mental stress tests both in the exercise (P = 0.96) and control (P = 0.24) experiments. After exercise, the blood pressure response to mental stress was attenuated (pre: 10 ± 13 vs post: 6 ± 7 mmHg; P < 0.01) along with lower values of systolic blood pressure (pre: 129 ± 3 vs post: 125 ± 3 mmHg; P < 0.05), stroke volume (pre: 89.4 ± 3.5 vs post: 76.8 ± 3.8 mL; P < 0.05), and cardiac output (pre: 7.00 ± 0.30 vs post: 6.51 ± 0.36 L/min; P < 0.05). Except for heart rate, the hemodynamic responses and the mean values during the two mental stress tests in the control experiment were similar (P > 0.05). In conclusion, a single bout of maximal dynamic exercise attenuates the blood pressure response to mental stress in healthy subjects, along with lower stroke volume and cardiac output, denoting an acute modulatory action of exercise on the central hemodynamic response to mental stress.
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En este trabajo se determinó la vida útil de una fórmula dietética para niños con síndrome diarréico, empleando la disminución de lisina disponible como indicador de deterioro. Muestras del producto fueron empacadas en envases de material multilaminado (papel-plástico-aluminio) y almacenadas a 25, 30 y 35°C, por dos meses. La lisina disponible fue medida con una frecuencia semanal y los datos fueron analizados para determinar la cinética de la reacción de deterioro y su relación con la temperatura. Al finalizar el estudio, la cantidad de lisina disponible remanente fue de 38,5% (a 25°C); 15,3 % (a 30°C) y 14,1% (a 35°C). La cinética de la reacción de deterioro fue de orden uno, dependiente de la temperatura de almacenamiento, según la ecuación de interrelación de Arrhenius, con un valor de energía de activación de 15,17 kcal/mol, por lo que cae dentro del rango de las reacciones de oxidación de lípidos. De acuerdo a las características del producto [contenido de lípidos (17,5%), proteínas (17,3%) y una actividad de agua de 0,46], la disminución de lisina pudiera ser explicada por la interacción de productos de oxidación de lípidos con proteínas. Considerando un valor de 0,422g lis/100g producto como punto crítico, se predijo la vida útil del producto a temperaturas diferentes a las evaluadas. Condiciones de almacenamiento por debajo de 30°C, garantizan un mayor período de vida útil: hasta 9 meses a 15°C, 6 meses a 20°C y 3 meses a 28°C, en función del indicador de deterioro evaluado.
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El conocimiento de las propiedades viscoelásticas de los alimentos es muy útil en el diseño y predicción de la estabilidad de muestras almacenadas. El trabajo tuvo como objetivos caracterizar las propiedades viscoelásticas de las muestras de pulpa de membrillo a diferentes concentraciones de sólidos solubles. El estudio reológico del pulpa de membrillo fue realizado en el rango de concentraciones de 12,3 a 28°Brix a la temperatura de 20°C. Las medidas viscoelásticas fueron realizadas con un reômetro Haake Rheostress RS100 y fue seleccionado el barrido de frecuencia entre 0,1 a 100 Hz. Los resultados demostraron que para la muestra de 28°Brix la pulpa se comportó como un semi-sólido en todo el rango de frecuencia estudiada. Para la concentración de 24°Brix, a bajas frecuencias, la pulpa se comportó como un semi-líquido (G">G') mientras que en frecuencias más altas se comportó como semi-sólido (G'>G"). Para la pulpa de 16 e 20°Brix hubo el predominio del carácter viscoso sobre el carácter elástico. Para la pulpa de 12,3°Brix no fue posible determinar los valores G' e G". Se observó todavía que la viscosidad compleja del pulpa de membrillo aumenta con la concentración para todo el rango de frecuencias estudiadas.
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O objetivo da palestra foi o de apresentar um apanhado sucinto da história das investigações sobre conceitos nas últimas décadas, com isso contribuindo para a divulgação da Ciência Cognitiva. O episódio central dessa história é a guinada resultante das pesquisas realizadas por Eleonor Rosch e outros a partir do inicio dos anos setenta. Estas pesquisas colocam em cheque a CONCEPÇÃO CLÁSSICA DE CONCEITOS (caracterizada na primeira parte da exposição). O fato de que o abandono da concepção clássica não é uma alternativa viável, dá origem ao que chamamos de PROBLEMA DA CONCILIAÇÃO, ou seja, o de compatibilizar a concepção clássica com as descobertas modernas. A apresentação se encerra com algumas sugestões para a solução do problema.
Resumo:
Investigaremos, a partir da perspectiva da Ciência Cognitiva, a noção de representação mental, no domínio da percepção visual humana. Ênfase é dada ao paradigma Conexionista, ou de Redes Neurais, de acordo com o qual tais representações mentais são descritas como estruturas emergentes da interação entre sistemas de processamento de informação que se auto-organizam - tais como o cérebro - e a luz estruturada no meio ambiente. Sugerimos que essa noção de representação mental indica uma solução para uma antiga polêmica, entre Representacionalistas e Eliminativistas, acerca da existência de representações mentais no sistema perceptual humano.
Resumo:
Raciocinando no contexto do programa neomecanicista para a Biologia, estudamos a natureza do processamento de informação no sistema vivo em geral, e no cérebro humano em particular, onde uma aplicação do modelo da Auto-Organização nos conduz à hipótese do "Supercódigo". Este seria um programa mental, molecularmente codificado, responsável pelas competências inatas, como a competência lingüística. Fazemos também uma comparação entre nossa hipótese e a da Linguagem do Pensamento, proposta por Jerry Fodor.
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ABSTRACT: The mental models theory predicts that, while conjunctions are easier than disjunctions for individuals, when denied, conjunctions are harder than disjunctions. Khemlani, Orenes, and Johnson-Laird proved that this prediction is correct in their work of 2014. In this paper, I analyze their results in order to check whether or not they really affect the mental logic theory. My conclusion is that, although Khemlani et al.'s study provides important findings, such findings do not necessarily lead to questioning or to rejecting the mental logic theory.
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