Neural compensation for compliant loads during rhythmic movement

An experiment was performed to characterise the movement kinematics and the electromyogram (EMG) during rhythmic voluntary flexion and extension of the wrist against different compliant (elastic-viscous-inertial) loads. Three levels of each type of load, and an unloaded condition, were employed. The movements were paced at a frequency of I Hz by an auditory metronome, and visual feedback of wrist displacement in relation to a target amplitude of 100degrees was provided. Electro-myographic recordings were obtained from flexor carpi radialis (FCR) and extensor carpi radialis brevis (ECR). The movement profiles generated in the ten experimental conditions were indistinguishable, indicating that the CNS was able to compensate completely for the imposed changes in the task dynamics. When the level of viscous load was elevated, this compensation took the form of an increase in the rate of initial rise of the flexor and the extensor EMG burst. In response to increases in inertial load, the flexor and extensor EMG bursts commenced and terminated earlier in the movement cycle, and tended to be of greater duration. When the movements were performed in opposition to an elastic load, both the onset and offset of EMG activity occurred later than in the unloaded condition. There was also a net reduction in extensor burst duration with increases in elastic load, and an increase in the rate of initial rise of the extensor burst. Less pronounced alterations in the rate of initial rise of the flexor EMG burst were also observed. In all instances, increases in the magnitude of the external load led to elevations in the overall level of muscle activation. These data reveal that the elements of the central command that are modified in response to the imposition of a compliant load are contingent, not only upon the magnitude, but also upon the character of the load.

The 2000 Ogura Lecture: Olfactory neural cells: An untapped diagnostic and therapeutic resource

Objective. This is an over-view of the cellular biology of upper nasal mucosal cells that have special characteristics that enable them to be used to diagnose and study congenital neurological diseases and to aid neural repair. Study Design: After mapping the distribution of neural cells in the upper nose, the authors' investigations moved to the use of olfactory neurones to diagnose neurological diseases of development, especially schizophrenia. Olfactory-ensheating glial cells (OEGs) from the cranial cavity promote axonal penetration of the central nervous system and aid spinal cord repair in rodents. The authors sought to isolate these cells from the more accessible upper nasal cavity in rats and in humans and prove they could likewise promote neural regeneration, making these cells suitable for human spinal repair investigations. Methods: The schizophrenia-diagnosis aspect of the study entailed the biopsy of the olfactory areas of 10 schizophrenic patients and 10 control subjects. The tissue samples were sliced and grown in culture medium. The ease of cell attachment to fibronectin (artificial epithelial basement membrane), as well as the mitotic and apoptotic indices, was studied in the presence and absence of dopamine in those cell cultures. The neural repair part of the study entailed a harvesting and insertion of first rat olfactory lamina propria rich in OEGs between cut ends of the spinal cords and then later the microinjection of an OEG-rich suspension into rat spinal cords previously transected by open laminectomy. Further studies were done in which OEG insertion was performed up to 1 month after rat cord transection and also in monkeys. Results: Schizophrenic patients' olfactory tissues do not easily attach to basement membrane compared with control subjects, adding evidence to the theory that cell wall anomalies are part of the schizophrenic lesion of neurones. Schizophrenic patient cell cultures had higher mitotic and apoptotic indices compared with control subjects. The addition of dopamine altered these indices enough to allow accurate differentiation of schizophrenics from control patients, leading to, possibly for the first time, an early objective diagnosis of schizophrenia and possible assessment of preventive strategies. OEGs from the nose were shown to be as effective as those from the olfactory bulb in promoting axonal growth across transected spinal cords even when added I month after injury in the rat. These otherwise paraplegic rats grew motor and proprioceptive and fine touch fibers with corresponding behavioral improvement. Conclusions. The tissues of the olfactory mucosa are readily available to the otolaryngologist. Being surface cells, they must regenerate (called neurogenesis). Biopsy of this area and amplification of cells in culture gives the scientist a window to the developing brain, including early diagnosis of schizophrenia. The Holy Grail of neurological disease is the cure of traumatic paraplegia and OEGs from the nose promote that repair. The otolaryngologist may become the necessary partner of the neurophysiologist and spinal surgeon to take the laboratory potential of paraplegic cure into the day-to-day realm of clinical reality.

Neural control of the heart: developmental changes in ionic conductances in mammalian intrinsic cardiac neurons

The expression and properties of ionic channels were investigated in dissociated neurons from neonatal and adult rat intracardiac ganglia. Changes in the hyperpolarization-activated and ATP-sensitive K+ conductances during postnatal development and their role in neuronal excitability were examined. The hyperpolarization-activated nonselective cation current, I-h, was observed in all neurons studied and displayed slow time-dependent rectification. An inwardly rectifying K+ current, I-K(I), was present in a population of neurons from adult but not neonatal rats and was sensitive to block by extracellular Ba2+. Using the perforated-patch recording configuration, an ATP-sensitive K+ (K-ATP) conductance was identified in greater than or equal to 50% of intracardiac neurons from adult rats. Levcromakalim evoked membrane hyperpolarization, which was inhibited by the sulphonylurea drugs. glibenclamide and tolbutamide. Exposure to hypoxic conditions also activated a membrane current similar to that induced by levcromakalim and was inhibited by glibenclamide. Changes in the complement of ion channels during postnatal development may underlie observed differences in the function of intracardiac ganglion neurons during maturation. Furthermore, activation of hyperpolarization-activated and KATP channels in mammalian intracardiac neurons may play a role in neural regulation of the mature heart and cardiac function during ischaemia-reperfusion. (C) 2002 Elsevier Science B.V All rights reserved.

Anomalies in the developing neural and visceral head skeleton of the Australian lungfish, Neoceratodus forsteri

Several anomalies occur in the developing neural and visceral head skeleton of young specimens of Neoceratodus forsteri that have been reared under laboratory conditions. These include anomalies of the basicranium and its derivatives, aberrations of the anterior mandible and hyoid apparatus, and abnormalities in the articulation of the jaws and the elements that produce them. Apart from the occasional absence of the basihyal, and failure of the quadrate processes to form, the anomalies are not deficiencies. Most involve malformations of parts of the neurocranium and visceral skeleton, inappropriate articulations or fusions between elements, disunity in structures that are normally fused and the appearance of supernumerary elements. The incidence of chondral anomalies, generally higher than aberrations that occur in the dermal skeleton in juvenile lungfish, ranges from 1-10% in laboratory reared individuals that have not been subjected to experimental interference. The anomalies differ from those found in many amphibian populations, in the field and in the laboratory, because they involve the cranium, and not the limbs, and the lungfish have not been exposed to the factors that cause anomalies in the amphibians. It is unlikely that the existence of those anomalies, if it is reflected in the wild population, places a selective pressure on the lungfish, because, in a normal season, less than 1% of the total number of eggs produced survive to be recruited into the adult population.

Segmenting the market of West Australian senior tourists using an artificial neural network

Measuring perceptions of customers can be a major problem for marketers of tourism and travel services. Much of the problem is to determine which attributes carry most weight in the purchasing decision. Older travellers weigh many travel features before making their travel decisions. This paper presents a descriptive analysis of neural network methodology and provides a research technique that assesses the weighting of different attributes and uses an unsupervised neural network model to describe a consumer-product relationship. The development of this rich class of models was inspired by the neural architecture of the human brain. These models mathematically emulate the neurophysical structure and decision making of the human brain, and, from a statistical perspective, are closely related to generalised linear models. Artificial neural networks or neural networks are, however, nonlinear and do not require the same restrictive assumptions about the relationship between the independent variables and dependent variables. Using neural networks is one way to determine what trade-offs older travellers make as they decide their travel plans. The sample of this study is from a syndicated data source of 200 valid cases from Western Australia. From senior groups, active learner, relaxed family body, careful participants and elementary vacation were identified and discussed. (C) 2003 Published by Elsevier Science Ltd.

Tyrosinase-Cre mice for tissue-specific gene ablation in neural crest and neuroepithelial-derived tissues

This study describes the derivation of two new lines of transgenic mice that express Cre recombinase under the control of tyrosinase transcriptional elements. To determine the suitability of the Tyrosinase-Cre transgene for tissue-specific gene ablation studies, a fate map of Cre expression domains was determined using the Z/AP reporter strain. It was shown that Cre-expressing cells contribute to a wide array of neural crest and neuroepithelial-derived lineages. The melanocytes of the harderian gland and eye choroid, sympathetic cephalic ganglia, leptomeninges of the telencephalon, as well as cranial nerves (V), (VII), and (IX) are derived either fully or partly from Cre-expressing cephalic crest. The cells contributing to the cranial nerves were the first to exhibit Cre expression at E10.5 as they were migrating into the branchial arches. The melanocytes, chromaffin cells of the adrenal medulla, and dorsal root ganglia are derived from trunk neural crest that either express Cre or were derived from Cre-expressing precursors. An array of brain tissue including the basal forebrain, hippocampus, olfactory bulb, and the granule cell layer of the lateral cerebellum, as well as the retinal pigmented epithelium and glia of the optic nerve originate from Cre-expressing neuroepithelial cells. (C) 2003 Wiley-Liss, Inc.

Teleassist??ncia em rede para regi??es remotas: melhorando o acesso da popula????o ?? aten????o especializada em sa??de

A iniciativa, implementada em Minas Gerais, ?? considerada uma das maiores experi??ncias de teleassist??ncia sustent??vel no mundo, servindo de modelo para outras a????es similares no Brasil e na Am??rica Latina. Sua cria????o representa uma nova atividade econ??mica, gerando um novo campo de trabalho e uma nova ??rea de pesquisa, tanto na sa??de quanto na ??rea de TI. Os resultados alcan??ados impactaram positivamente a melhoria do acesso da popula????o a servi??os especializados e a fixa????o de profissionais em localidades remotas

Rede Nacional de Altos Estudos em Seguran??a P??blica (Renaesp)

A Rede Nacional de Altos Estudos em Seguran??a P??blica (Renaesp) ?? um projeto de educa????o permanente, democr??tica e qualificada, promovido a partir da parceria com institui????es de ensino superior ??? que recebem investimentos para realizar cursos nas modalidades presencial e a dist??ncia ??? para a promo????o de p??s-gradua????o na ??rea de seguran??a p??blica. O objetivo principal da rede ?? democratizar o acesso dos profissionais de seguran??a p??blica ??? sem distin????o hier??rquica ??? aos processos de aprendizagem e aperfei??oamento profissional. Busca-se difundir entre esses profissionais e as institui????es em que trabalham o conhecimento e a capacidade cr??tica necess??rios ?? constru????o de um novo modo de fazer seguran??a p??blica, comprometido com a cidadania e os direitos humanos. A iniciativa destina-se aos policiais federais, rodovi??rios federais, policiais civis e militares, agentes penitenci??rios, peritos criminais e guardas municipais. Presente em 26 estados, a Renaesp j?? capacitou 5.250 profissionais

Rede Suas: o sistema nacional de informa????o da assist??ncia social

A Rede SUAS ?? o sistema de informa????o do Sistema ??nico de Assist??ncia Social ??? SUAS e tem a fun????o de responder ??s novas necessidades de informa????o e comunica????o no ??mbito do SUAS, que ?? a regula????o ampliada da Constitui????o Federal de 88, no que tange ?? pol??tica p??blica de assist??ncia social, integrante do sistema brasileiro de seguridade social. Considerada como um instrumento de gest??o colegiada, a Rede SUAS inaugurou para os trabalhadores, gestores e entidades da ??rea, a tarefa de redimensionar a cultura de gest??o, at?? ent??o vivenciada, com a instala????o de aplicativos que geram novos ??ndices de agilidade e transpar??ncia, dando suporte aos processos e procedimentos previstos na Pol??tica Nacional de Assist??ncia Social, 2004, PNAS e na norma operacional b??sica do SUAS/2005. O projeto resolve duas quest??es centrais para a ??rea: a revers??o das tend??ncias que caracterizaram experi??ncias anteriores de gest??o e a necess??ria associa????o dos instrumentos e condi????es tecnol??gicas de produ????o, recebimento, tratamento, armazenamento e entrega de dados e informa????o, com as opera????es de gest??o, financiamento e controle social da pol??tica p??blica de assist??ncia social

Projeto Rede Nacional de Agentes de Com??rcio Exterior: Redeagentes

?? fato concreto que as exporta????es no Brasil sofrem uma s??rie de entraves. Com clareza, podemos observar que um deles ?? a falta de informa????o do empresariado brasileiro a respeito do processo de exporta????o. Para minimizar esse problema, em meados do ano de 1999, come??aram a ser discutidas a????es efetivas que o governo poderia realizar. Foi, ent??o, criado o Programa Cultura Exportadora, abarcado pelo Programa Avan??a Brasil e pelo Programa Especial de Exporta????es. O seu objetivo ?? aumentar a participa????o das micro e pequenas empresas no processo exportador e, com isso, diminuir a concentra????o que existe na pauta de exporta????es brasileira

Gerenciamento da rede de supervis??o da Eletronorte (GerenteSage)

Como solu????o unificadora da opera????o, em tempo real, de seus sistemas el??tricos, a Eletronorte utiliza, desde 1998, o Sistema Aberto de Gerenciamento de Energia (Sage), que habilita seus centros de opera????o a serem centros estrat??gicos de tratamento de informa????o. A import??ncia do Sage para a empresa reflete-se na relev??ncia da rede que comporta seus dados. Para garantir elevados graus de disponibilidade dos servi??os de supervis??o, foi implementada a ferramenta GerenteSage, que gerencia os recursos da rede e facilita o controle deles pelos administradores. Para essa ferramenta, foi definida uma interface web, a qual condiz com caracter??sticas atuais do mundo da inform??tica: a descentraliza????o do acesso ??s informa????es e a independ??ncia de plataforma para o usu??rio. Outro aspecto importante da metodologia de concep????o ?? a utiliza????o de sistemas e fontes livres. Como resultado, houve melhora na qualidade dos servi??os de rede e aumento da disponibilidade das informa????es de supervis??o