bluuebunny/crossref_metadata_2025 huggingface dataset:
LINCHAMENTOS EM REDE: JUSTIÇAMENTO E VIOLÊNCIA-RESPOSTA NA INTERNET
Authors: Lobo Rafael De Almeida Ávila , Filho Max Suel Dummer Coutinho
Published: April 2018

Um indivíduo acusado de cometer um crime brutal é cercado por um grupo de pessoas que criam ali uma cena de justiçamento para linchá-lo em virtude do ato socialmente condenável supostamente cometido por ele. Essa é uma cena conhecida e recorrente no imaginário social brasileiro, sobretudo estando relacionada a ocorrência em bairros periféricos e tendo como alvo da ira popular um homem jovem, pobre e negro. No entanto, tem sido cada vez mais comum encontrar esse tipo de cena ocorrendo na internet. Ou seja, temos encontrado a prática do linchamento ocorrendo em espaços de sociabilidade das redes. Este trabalho objetivou o estudo das ocorrências de linchamentos na rede mundial de computadores. Tal fenômeno foi investigado nos fóruns-apêndice das notícias de portais da internet, espaço destinado aos comentários e interações de leitores e onde tal prática é bastante efusiva. Nesses espaços pudemos encontrar a ocorrência de linchamentos discursivamente construídos e simbolicamente executados. Embora os linchamentos em rede de certa forma se aproximem dos linchamentos tradicionais em vários sentidos, percebemos que eles possuem suas especificidades em virtude de uma série de fatores, envolvendo desde dinâmicas próprias do local onde ocorrem bem como das novas sociabilidades que se constituem no ciberespaço. Este trabalho buscou compreender a ocorrência do fenômeno identificando suas características e contextualizando tanto com o cenário sociocultural brasileiro, a partir da bibliografia disponível, quanto com as novas sociabilidades constituídas nas redes na contemporaneidade, mediante trabalho documental.
APRESENTAÇÃO: GEORG SIMMEL E AS FORMAS DE VIDA
Authors: Bueno Arthur , Malta Eder , Leite Elaine Da Silveira
Published: April 2018

É notável, nos últimos anos, o crescimento da produção acadêmica arespeito da obra do filósofo e sociólogo alemão Georg Simmel (1858-1918)
DISCUSSÕES SOBRE O TRABALHO FEMININO NA POLÍCIA MILITAR DO ESTADO DE SÃO PAULO
Authors: Bueno Denari Giulianna
Published: April 2018

A presente proposta discute alguns aspectos do trabalho feminino na Polícia Militar do Estado de São Paulo (PMESP), apresentando sua história de inserção e as diversas funções femininas e conflitos que a presença dessas mulheres acarretaram. A pesquisa teve como metodologia qualitativa entrevistas semiestruturadas realizadas em diversas cidades do estado de São Paulo, com policiais mulheres e homens, de diversas patentes e funções. O trabalho feminino na instituição surgiu como assistencialista visando às populações vulneráveis que chegavam todos os dias na capital no contexto das migrações da década de 1950. Diferentemente do contexto de inserção das mulheres no mercado de trabalho, as policiais femininos (categoria nativa) tiveram sua inserção restrita, porém com os mesmos direitos que os policiais homens da época. Com o passar dos anos e mudanças na própria instituição policial, o trabalho feminino foi se aproximando do trabalho ostensivo e se afastando do trabalho assistencialista, homogeneizando as formas de policiamento da PMESP. Podemos concluir que o trabalho policial feminino não seguiu as tendências do trabalho feminino no Brasil como um todo no que diz respeito à jornada, pagamento e direitos, porém, podemos falar sobre processo de trabalho precário, quando entendemos as dificuldades e obstáculos que as mulheres enfrentaram e enfrentam dentro da instituição.
Síntese e caracterização de óxido de grafeno e óxido de grafeno reduzido para aplicação ambiental
Authors: Ávila Elizete Souza , Melo Caio Cesar , Sampaio Tanyse Parada , Machado Fernando Machado
Published: April 2018

O presente trabalho apresenta a síntese via método Hummers de óxido de grafeno a partir de duas formas de grafites, em pó e em flakes. Ainda, é apresentada a redução química do óxido de grafeno produzido com a forma de grafite mais eficiente. Os grafites precursores, assim como os óxidos de grafeno e óxido de grafeno reduzido produzidos foram caracterizados através das técnicas de difração raios X e espectroscopia Raman. A rota de síntese utilizada se apresentou bastante eficiente, obtendo-se nanomateriais com alto grau de oxidação e esfoliação. No que diz respeito a forma do grafite precursor, o grafite em pó se mostrou mais indicado para a síntese de óxido de grafeno. Isso se deve, provavelmente, a maior facilidade nas etapas de oxidação e esfoliação do material. A partir das caracterizações, é possível verificar que o óxido de grafeno sintetizado com o pó de grafite possui boa qualidade. Ainda, a partir do óxido de grafeno oriundo do pó de grafite, foi possível obter óxido de grafeno reduzido utilizando borohidreto de sódio com redutor. Vale ressaltar que os nanomateriais aqui produzidos possuem grande potencial para aplicações como adsorventes no tratamento de efluentes contaminados com contaminantes emergentes.
Desenvolvimento de compósitos de matriz metálica reforçados com carbeto de nióbio
Authors: Vieira Janete Viegas , Da Rosa Leonardo Maciel , Osório Alice , Alano José Henrique
Published: April 2018

O objetivo do presente trabalho baseia-se em avaliar uma matriz metálica de aço 316L com adição de 1,3, 5 e 10% de carbeto de nióbio em peso, a temperatura de 1150°C e tempo de sinterização de 60minem forno tubular resistivo com atmosfera controlada em nitrogênio, bem como verificar as propriedades mecânicas, morfológicas e químicas com diferentes proporções matriz/reforço, tais como dureza, análise de superfície em microscópio ótico para verificar a dispersão do carbeto na matriz, análise de difração de raios Xe ensaio de corrosão do material. Os resultados apresentaram boa sinterabilidade nestes parâmetros, comprovada pelas imagens de microscopia e difração de raios X, e o componente desenvolvido apresentou melhora na dureza quando comparado ao mesmo material sem reforço de carbeto de nióbio.
Avaliação do risco a inundação correlacionado com áreas afetadas por evento anterior no município de Pelotas, RS
Authors: Lima Gustavo Farias , Leandro Diuliana , Quadro Maurizio Silveira , Nadaleti William Cezar , Barcelos Amauri Antunes
Published: April 2018

A área urbana do município de Pelotas apresenta um relevo com cotas baixas e um histórico significativo de desastres naturais relacionados à inundação. Com o auxílio da avaliação dos riscos e o mapeamento das áreas afetadas por eventos  anteriores é possível a criação de medidas de planejamento e ação pelos órgãos competentes, assim como estudos ambientais para a área. Através deste estudo foram classificadas 5 classes de risco para a área municipal, sendo 4,7% da área municipal classificada como risco muito baixo ou baixo, já 49,35% da área total ficou classificada como médio e como risco alto ou muito alto ficou 45,95% do município. As áreas afetadas pelo evento de outubro de 2015 apresentar relação espacial com as áreas classificadas com risco alto e muito alto.
Viabilidade da borra de tinta na aplicação da técnica de coprocessamento em fornos de cimento
Authors: Barbosa Francis André Triches , Crippa Liziane Bertotti
Published: April 2018

As tintas estão cada vez mais sendo aplicadas em várias atividades e sendo desenvolvidas para que se tornem menos poluentes ao meio ambiente. Um dos principais desa os ambientais é a destinação adequada destes resíduos. Foi realizado um estudo sobre a aceitabilidade de amostras de borras de tintas de três tipos de indústrias na técnica de coprocessamento em fornos de cimento. O estudo apresentou que 77% das amostras estavam aptas para coprocessamento de acordo com a licença de operação para empresas de blendagem emitida pela FEPAM – Fundação Estadual de Proteção Ambiental Henrique Luiz Roessler do Rio Grande do Sul. Portanto permite uso mais nobre do material que não o envio a aterro sanitário ou até mesmo locais inapropriados que representa um ganho principalmente para o meio ambiente.
The physical and mechanical properties of recycled gypsum and potential application of pre-molded panels
Authors: Savi Olindo , Souza Rafael Alves , Mascia Nilson Tadeu , Souza Mateus Henrique
Published: April 2018

This study analyses the physical properties of recycled gypsum and mechanical performance of pre-molded gypsum panels made of recycled gypsum. A compatation with commercial gypsum physical properties and mechanica behavior of pre-molded commercial gypsum panels is also carried out. After collection, recycling and grinding gypsum residues, the quality of the powder produced was evaluated in terms of units of mass and fineness modulus. Additional tests of the dry paste were conducted for assessment of hardness, water absorption, and compressive strength of recycled gypsum. The commercial potential of the material was evaluated by the bending strength testing pre-molded panels. The results demonstrate that gypsum recycling is sustainable, ecologically correct and feasible for the production of pre-molded elements with great potential use in civil construction. Keywords: gypsum panels, mixed pastes, sustainable, gypsum pastes.
TRATAMENTO DE EFLUENTE CONTENDO FLUFENOXURON GERADO PELA LAVAGEM E DESCARTE DAS APLICAÇÕES AÉREAS
Authors: Furtado Ricardo Dourado , Hoff Rodrigo Barcellos
Published: April 2018

A legislação ambiental brasileira, subsidiada pela Instrução Normativa no 02/2008 do Ministério da Agricultura, Pecuária e Abastecimento, obriga que as empresas operadoras aeroagrícolas realizem o tratamento dos e uentes gerados após a lavagem das aeronaves. Para este m, é sugerido pela legislação o uso de um sistema de degradação baseado na ozonização. Avaliou-se a e ciência do sistema recomendado pela legislação em promover a degradação do princípio ativo ufenoxuron (inseticida Cascade® 100), onde foram analisadas a concentração e a quantidade em massa da molécula em todas as etapas do sistema. Foram avaliados dois tratamentos distintos, usando 1,0 e 2,0 g de ozônio/hora, em um sistema industrial de geração de ozônio, usando três períodos de ozonização diferentes (1, 3 e 6 horas), em temperatura ambiente e pH em torno de 6,0. Constatou-se que, em cada lavagem, é gerado um volume médio de 132 L de e uente (112 L de água mais 20 L de calda residual). Após sofrer os tratamentos com 1,0 e 2,0 g de O3/hora foram obtidos, respectivamente, os seguintes resultados: diminuição da concentração de ufenoxuron no e uente (-82,8 e -86,0%) e decréscimo na massa de ufenoxuron (-44,8 e -63,2%). O sistema mostrou-se e ciente no tratamento do e uente contendo resíduos do inseticida Cascade® 100.
Germinação de sementes e estabelecimento de mudas de goiabeira-serrana e Araçá-pera em diferentes substratos
Authors: Navroski Renan , Silva Pricila Santos da , Valeron Carolina , Malgarim Marcelo Barbosa , Mello-Farias Paulo
Published: April 2018

O presente trabalho teve como objetivo avaliar a emergência e o potencial de produção de mudas de goiabeira-serrana (Acca sellowiana (O.Berg) Burret) e araçazeiro-pera (Psidium acutangulum DC.), submetidas a diferentes substratos. O delineamento experimental foi inteiramente casualizado com 10 repetições por tratamento, sendo T1 (testemunha): apenas solo; T2: casca de arroz carbonizada + solo + areia; T3: casca de arroz carbonizada + areia + casca de arroz crua e T4: vermiculita expandida. A semeadura foi realizada em bandejas de isopor de 72 células. Avaliou-se, emergência, índice de velocidade de emergência, comprimento de parte aérea e de raízes, massa seca da parte aérea e raízes e teor de cloro la. Os substratos testados tem potencial para serem usados na propagação de goiaba-serrana e araçazeiro-pera. A mistura casca de arroz carbonizada + areia + casca de arroz crua apresentou resultados superiores quanto à emergência e índice de velocidade de emergência de goiaba-serrana. A vermiculita expandida destacou-se positivamente na emergência, índice de velocidade de emergência e atributos de desenvolvimento das mudas de araçazeiro-pera.
LOGÍSTICA REVERSA (LR): UM ESTUDO SOBRE OS CATADORES DE MATERIAL REAPROVEITÁVEL EM FREDERICO WESTPHALEN
Authors: Natalli Luiz Henrique , Munaretto Lorimar Francisco , Aguiar Jéssica Thalheimer
Published: April 2018

A Logística Reversa (LR) é um conjunto de atividades ligadas desde o decréscimo de matérias-primas primárias até a destinação do produto nal, como materiais e embalagens com o intuito de reutilizar e reciclar, dando outro destino aos materiais sem ser o lixo. O presente estudo teve por objetivo veri car a contribuição dos catadores de papel e papelão e material reaproveitável como forma de Logística Reversa (LR) na cidade de Frederico Westphalen - RS. Por meio de um instrumento de pesquisa semiestruturado, foram entrevistados 6 (seis) catadores que atuam na cidade de Frederico Westphalen – RS. Os resultados demonstram que os principais materiais coletados são o papelão, plástico, garrafas pet e latas de alumínio, sendo que são coletados em média 6100 kg de papelão, 2700 kg de plástico, 700 kg de garrafas pet e 670 kg de latas de alumínio por mês, o que contribuiu com uma renda mensal média de R$ 1060,00 (um mil e sessenta reais) para cada catador. Por meio do presente estudo, pode-se concluir que esta atividade traz uma contribuição na renda dos catadores além de contribuir signi cativamente para o meio ambiente.
UMA PROPOSIÇÃO DE PLANO DE NEGÓCIOS PARA PARQUES TECNOLÓGICOS: O CASO DE UMA UNIVERSIDADE DA REDE FEDERAL DE EDUCAÇÃO BRASILEIRA/PROPOSAL FOR A BUSINESS PLAN TO TECHNOLOGICAL PARKS: THE CASE OF A BRAZILIAN PUBLIC UNIVERSITY
Authors: Longaray André Andrade , Munhoz Paulo Roberto , Silva Diego Freitas da , Gonçalves Felipe Aguirre , Amaral Thauane Adamoli
Published: April 2018

Os Parques Tecnológicos configuram polos de desenvolvimento econômico e tecnológico que objetivam promover economias com base em conhecimento, por meio da interação entre universidades ou órgãos de pesquisa e empresas voltadas para pesquisa e desenvolvimento. Inúmeras políticas públicas de âmbito Nacional e Regional vêm sendo instituídas com vistas a fomentar os parques tecnológicos como agentes impulsionadores do desenvolvimento. O presente artigo descreve as etapas de elaboração da proposta de um Plano de Negócios para a implantação de um parque tecnológico em uma Universidade Federal localizada no Sul do Estado do Rio Grande do Sul. Metodologicamente, a pesquisa se caracteriza como exploratória conduzida por meio da técnica de estudo de caso. Como resultados, ficou evidenciada a capacidade tanto mercadológica quanto econômico-financeira de implantação e auto-sustentabilidade do Parque Tecnológico junto à Universidade objeto de estudo, o que tende a impulsionar maior desenvolvimento e atração de investidores.
DA VOCAÇÃO AO EMPREENDEDORISMO: O DILEMA DA MUDANÇA DE CARREIRA/THE CALLING TO ENTREPRENEURSHIP: CAREER CHANGE DILEMMA
Authors: Comin Lidiane Cássia , Sabadin Raquel Kraemer , Severo Eliana Andréa
Published: April 2018

O contexto do trabalho contemporâneo modificou as relações profissionais, as pessoas passaram a entender a carreira profissional, não mais como uma relação de tempo, mas caracterizada por uma relação recíproca de autonomia e responsabilidade, mudando assim a identidade profissional das pessoas. Carlos Silveira é um profissional, que ao se graduar em Odontologia e iniciar suas atividades profissionais, assim como muitos jovens que se formam e iniciam no mercado de trabalho, precisou tomar algumas decisões entre, permanecer atuando em sua profissão de recém-formado ou optar por um novo negócio. Sentindo-se desafiado pela situação, questionava-se qual seria a melhor escolha e quais seriam os esforços que gerariam melhores resultados alavancando sua carreira. O objetivo deste caso de ensino é estimular a reflexão sobre temas como a transição de carreira profissional, tomada de decisão, mudanças, empreendedorismo e estratégias profissionais. O caso oportuniza que o acadêmico assuma o papel do protagonista Carlos para tomar decisões acerca da problemática apresentada, bem como, a percepção das variáveis de mudança de carreira frente aos empreendimentos de um cenário futuro.
A política patrimonial atual do Brasil e a gestão compartilhada do patrimônio arqueológico na Amazônia
Authors: Silva Ana Cristina Rocha , Simonian Ligia Terezinha Lopes
Published: April 2018

O artigo aborda as relações entre a trajetória da política de preservação cultural do Brasil e a gestão do patrimônio arqueológico na Amazônia. O objetivo é refletir os reflexos da reorientação metodológica da política patrimonial no gerenciamento dos bens arqueológicos na região, de modo a discutir as modalidades com que o poder público fomenta a apropriação desses bens culturais, aliada aos pilares do desenvolvimento sustentável. As análises fundamentam-se na realidade de três regiões: Maracá (AP); Calçoene (AP); e Monte Alegre (PA). Concluiu-se que a reorientação metodológica da política patrimonial não sinaliza ressonância na constituição de uma gestão densa e efetiva para o patrimônio arqueológico nessas regiões. Ao perpetuar práticas centralizadoras e seletivas, a gestão do bem destacado reproduz a lógica tradicional da política do patrimônio. Dificulta, assim, que a sociedade civil possa conduzir e protagonizar o processo de apropriação de seu meio ambiente cultural.
O homem como agente transformador da paisagem
Authors: Pacheco Carvalho Aline Beatriz
Published: April 2018

Este ensaio visual evidencia modificações na paisagem natural no município de Glorinha, Rio Grande do Sul, a partir das interações entre os seres humanos e os ecossistemas naturais. Os registros fotográficos foram obtidos entre os meses de agosto a outubro de 2017, organizados e discutidos a partir de três eixos temáticos: paisagem natural, vestígios e impactos na paisagem. As fotografias demonstram a modelagem da paisagem de Glorinha ao longo do tempo e história do município.  Palavras-chave: Natureza. Cultura. Impacto.
Ontogenetic development of postural control in man: adaptation to altered support and visual conditions during stance
Authors: Forssberg H , Nashner LM
Published: April 2018

Normal young children ranging in age from 1 1/2 to 10 years were assessed in a number of experimental paradigms testing the ability to adapt quickly their strategy of control to altered support surface and visual conditions. The experimental protocols, using a movable platform and visual surround, and the analytic techniques, using EMGs and measures of reaction forces and body motions, were identical to those employed in a complementary study in this issue (Nashner, L. M., F. O. Black, and C. Wall, III (1982) J. Neurosci. 2: 536–544). The structure of automatic postural adjustments in young children was, with the exception of greater variability, similar to that of adult subjects studied previously. However, young children below the age of 7 1/2 years were unable to suppress systematically the influence of inputs derived from the support surface or from vision when these provided inappropriate orientation information due to the motion of these surfaces. The discussion emphasizes that the automatic postural adjustments and the context-dependent reweighting of support surface, vestibular, and visual inputs are organizationally separate processes and that the hierarchically lower level automatic process matures before the higher level adaptive processes.
Characterization of the daily oxytocin rhythm in primate cerebrospinal fluid
Authors: Artman HG , Reppert SM , Perlow MJ , Swaminathan S , Oddie TH , Fisher DA
Published: April 2018

The circadian characteristics of the daily rhythm in oxytocin (OT) concentrations in cerebrospinal fluid (CSF) were studied in the rhesus monkey. Monkeys subjected to constant light or constant dark for periods of 3 to 6 days manifested persistence of the CSF OT rhythm. A 12-hr phase shift in the light-dark cycle resulted in a resynchronization of the rhythm to the new lighting schedule within 3 to 4 days. Altering the daily feeding and care schedule during a period of constant darkness did not alter the expression or timing of the CSF OT rhythm significantly. These results suggest that the OT rhythm is endogenously generated and that the daily light-dark cycle normally synchronizes the rhythm to the 24-hr cycle.
Influences of the Thalamus on the Survival of Subplate and Cortical Plate Cells in Cultured Embryonic Mouse Brain
Authors: Price David J. , Lotto R. Beau
Published: April 2018

The afferent and efferent connections of the cerebral neocortex develop simultaneously toward the end of embryogenesis. At this stage, the neocortex comprises two main cell-dense layers: the thicker and more superficial cortical plate (future layers 2–6) and the thinner underlying subplate. Many early thalamocortical projections temporarily innervate the subplate before leaving it to locate their ultimate targets in the overlying cortical plate. The subplate then disappears. In this study, we performedin vitroexperiments on late embryonic murine brain to test whether the thalamus can influence the survival of cortical plate and subplate cells at this stage. In isolated organotypic cortical explants from embryonic day 19 mice, most of the cells that had formed the subplate died. Coculture with a thalamic explant prevented this loss; coculture with additional cortical or cerebellar explants did not. By contrast, many cells in or destined for the cortical plate survived even in isolated cortical explants; coculture with a thalamic explant did not alter the numbers of these cells that survived. Our results suggest that the thalamus provides trophic support for subplate cells but not for late embryonic cortical plate cells.In vivo, a loss of thalamic-derived trophic support for the subplate late in embryogenesis, consequent on the movement of thalamocortical axons into the cortical plate, may contribute to subplate death.
Implementation of Action Sequences by a Neostriatal Site: A Lesion Mapping Study of Grooming Syntax
Authors: Cromwell Howard C. , Berridge Kent C.
Published: April 2018

The neostriatum and its connections control the sequential organization of action (“action syntax”) as well as simpler aspects of movement. This study focused on sequential organization of rodent grooming. Grooming syntax provides an opportunity to study how neural systems coordinate natural patterns of serial order. The most stereotyped of these grooming patterns, a “syntactic chain,” has a particularly stereotyped order that recurs thousands of times more often than could occur by chance. The purpose of the present study was to identify the crucial site within the striatopallidal system where lesions disrupt the syntax or serial order of syntactic grooming chains without disrupting constituent movements. Small excitotoxin lesions were made using quinolinic acid at bilateral sites within the dorsolateral, dorsomedial, ventrolateral, or ventromedial neostriatum, or in the ventral pallidum or globus pallidus of rats. An objective technique for mapping functional lesions was used to quantify cell death and to map precisely those lesions that disrupted grooming syntax. Our results identified a single site within the anterior dorsolateral neostriatum, slightly more than a cubic millimeter in size (1.3 × 1.0 × 1.0 mm), as crucial to grooming syntax. Damage to this site did not disrupt the ability to emit grooming actions. By contrast, damage to sites in the ventral pallidum and globus pallidus impaired grooming actions but left the sequential organization of grooming syntax intact. Neural circuits within this crucial “action syntax site” seem to implement sequential patterns of behavior as a specific function.
Ethanol Self-Administration Restores Withdrawal-Associated Deficiencies in Accumbal Dopamine and 5-Hydroxytryptamine Release in Dependent Rats
Authors: Weiss Friedbert , Parsons Loren H. , Schulteis Gery , Hyytiä Petri , Lorang Marge T. , Bloom Floyd E. , Koob George F.
Published: April 2018

Basal forebrain dopamine (DA) and 5-HT neurotransmission has been implicated in the mediation of the acute reinforcing actions of ethanol. Neuroadaptation theories predict that compensatory changes in neurochemical systems that are activated by alcohol acutely may underlie symptoms of withdrawal after chronic administration. To test this hypothesis, the release of DA and 5-HT was monitored by microdialysis in the nucleus accumbens of dependent male Wistar rats at the end of a 3–5 week ethanol (8.7% w/v) liquid diet regimen, during 8 hr of withdrawal, and during renewed availability of ethanol involving (1) the opportunity to operantly self-administer ethanol (10% w/v) for 60 min, followed by (2) unlimited access to the ethanol-liquid diet. Results were compared to control groups pair-fed with ethanol-free liquid diet and trained to self-administer either ethanol or water. In nondependent rats, operant ethanol self-administration increased both DA and 5-HT release in the NAC. Withdrawal from the chronic ethanol diet produced a progressive suppression in the release of these transmitters over the 8 hr withdrawal period. Self-administration of ethanol reinstated and maintained DA release at prewithdrawal levels but failed to completely restore 5-HT efflux. 5-HT levels recovered rapidly, however, within 1 hr of reexposure to ethanol liquid diet. These findings suggest that deficits in accumbal monoamine release may contribute to the negative affective consequences ethanol withdrawal and, thereby, motivate ethanol-seeking behavior in dependent subjects.
Metabotropic Glutamate Receptor Activation in Cerebellar Purkinje Cells as Substrate for Adaptive Timing of the Classically Conditioned Eye-Blink Response
Authors: Fiala John C. , Grossberg Stephen , Bullock Daniel
Published: April 2018

To understand how the cerebellum adaptively times the classically conditioned nictitating membrane response (NMR), a model of the metabotropic glutamate receptor (mGluR) second messenger system in cerebellar Purkinje cells is constructed. In the model, slow responses, generated postsynaptically by mGluR-mediated phosphoinositide hydrolysis and calcium release from intracellular stores, bridge the interstimulus interval (ISI) between the onset of parallel fiber activity associated with the conditioned stimulus (CS) and climbing fiber activity associated with unconditioned stimulus (US) onset. Temporal correlation of metabotropic responses and climbing fiber signals produces persistent phosphorylation of both AMPA receptors and Ca2+-dependent K+channels. This is responsible for long-term depression (LTD) of AMPA receptors. The phosphorylation of Ca2+-dependent K+channels leads to a reduction in baseline membrane potential and a reduction of Purkinje cell population firing during the CS–US interval. The Purkinje cell firing decrease disinhibits cerebellar nuclear cells, which then produce an excitatory response corresponding to the learned movement. Purkinje cell learning times the response, whereas nuclear cell learning can calibrate it. The model reproduces key features of the conditioned rabbit NMR: Purkinje cell population response is timed properly; delay conditioning occurs for ISIs of up to 4 sec, whereas trace conditioning occurs only at shorter ISIs; mixed training at two different ISIs produces a double-peaked response; and ISIs of 200–400 msec produce maximal responding. Biochemical similarities between timed cerebellar learning and photoreceptor transduction, and circuit similarities between the timed cerebellar circuit and a timed dentate-CA3 hippocampal circuit, are noted.
A Primary Acoustic Startle Pathway: Obligatory Role of Cochlear Root Neurons and the Nucleus Reticularis Pontis Caudalis
Authors: Lee Younglim , López Dolores E. , Meloni Edward G. , Davis Michael
Published: April 2018

Davis et al. (1982) proposed a primary acoustic startle circuit in rats consisting of the auditory nerve, posteroventral cochlear nucleus, an area near the ventrolateral lemniscus (VLL), nucleus reticularis pontis caudalis (PnC), and spinal motoneurons. Using fiber-sparing lesions, the present study reevaluated these and other structures together with the role of neurons embedded in the auditory nerve [cochlear root neurons (CRNs)], recently hypothesized to be involved in acoustic startle. Small electrolytic lesions of the VLL or ventrolateral tegmental nucleus (VLTg) failed to eliminate startle. Large electrolytic lesions including the rostral ventral nucleus of the trapezoid body (rVNTB) and ventrolateral parts of PnC or lesions of the entire PnC blocked startle. However, small NMDA-induced lesions of the rVNTB failed to block startle, making it unlikely that the rVNTB itself is part of the startle pathway. In contrast, NMDA lesions of the full extension of the ventrolateral part of the PnC blocked startle completely, suggesting that the ventrolateral part of the PnC is critically involved. Bilateral kainic acid lesions of CRNs also blocked the startle reflex completely, providing the first direct evidence for an involvement of CRNs in startle. This blockade probably was not caused by damage to the auditory nerve, because the lesioned animals showed intact compound action potentials recorded from the ventral cochlear nucleus. Hence, a primary acoustic startle pathway may involve three synapses onto (1) CRNs, (2) neurons in PnC, and (3) spinal motoneurons.
The Taste of Monosodium Glutamate: Membrane Receptors in Taste Buds
Authors: Chaudhari Nirupa , Yang Hui , Lamp Cynthia , Delay Eugene , Cartford Claire , Than Trang , Roper Stephen
Published: April 2018

Receptor proteins for photoreception have been studied for several decades. More recently, putative receptors for olfaction have been isolated and characterized. In contrast, no receptors for taste have been identified yet by molecular cloning. This report describes experiments aimed at identifying a receptor responsible for the taste of monosodium glutamate (MSG). Using reverse transcriptase (RT)-PCR, we found that several ionotropic glutamate receptors are present in rat lingual tissues. However, these receptors also could be detected in lingual tissue devoid of taste buds. On the other hand, RT-PCR and RNase protection assays indicated that a G-protein-coupled metabotropic glutamate receptor, mGluR4, also is expressed in lingual tissues and is limited only to taste buds.In situhybridization demonstrated that mGluR4 is detectable in 40–70% of vallate and foliate taste buds but not in surrounding nonsensory epithelium, confirming the localization of this metabotropic receptor to gustatory cells. Expression of mGluR4 in taste buds is higher in preweaning rats compared with adult rats. This may correspond to the known higher sensitivity to the taste of MSG in juvenile rodents. Finally, behavioral studies have indicated that MSG andl-2-amino-4-phosphonobutyrate (l-AP4), a ligand for mGluR4, elicit similar tastes in rats. We conclude that mGluR4 may be a chemosensory receptor responsible, in part, for the taste of MSG.
Characterization ofDrosophila Tyramine β-HydroxylaseGene and Isolation of Mutant Flies Lacking Octopamine
Authors: Monastirioti Maria , Linn, Jr. Charles E. , White Kalpana
Published: April 2018

Octopamine is likely to be an important neuroactive molecule in invertebrates. Here we report the molecular cloning of theDrosophila melanogastergene, which encodes tyramine β-hydroxylase (TBH), the enzyme that catalyzes the last step in octopamine biosynthesis. The deduced amino acid sequence of the encoded protein exhibits 39% identity to the evolutionarily related mammalian dopamine β-hydroxylase enzyme. We generated a polyclonal antibody against the protein product ofTβhgene, and we demonstrate that the TBH expression pattern is remarkably similar to the previously described octopamine immunoreactivity inDrosophila. We further report the creation of null mutations at theTβhlocus, which result in complete absence of TBH protein and blockage of the octopamine biosynthesis.Tβh-null flies are octopamine-less but survive to adulthood. They are normal in external morphology, but the females are sterile, because although they mate, they retain fully developed eggs. Finally, we demonstrate that this defect in egg laying is associated with the octopamine deficit, because females that have retained eggs initiate egg laying when transferred onto octopamine-supplemented food.
Visual Stimulation Regulates the Expression of Transcription Factors and Modulates the Composition of AP-1 in Visual Cortexa
Authors: Kaminska Bozena , Kaczmarek Leszek , Chaudhuri Avi
Published: April 2018

It is believed that long-term changes in neuronal function are orchestrated by transcription factors, such as AP-1 and ZIF 268, which are in turn regulated by synaptic stimulation. To further our understanding of the functional effects of such expression, we have examined the DNA-binding activities of both AP-1 and ZIF 268 by way of electrophoretic mobility shift assays (EMSA) on nuclear extracts from visual cortices of rats treated with selective light exposure. Visual stimulation after dark rearing increased the DNA-binding activities of both AP-1 and ZIF 268 to their highest levels within 2 hr. ZIF 268 thereafter dropped to levels similar to that observed in naive animals, whereas AP-1 DNA-binding activity continued to remain elevated even after 24 hr of stimulation. The components of the AP-1 complex, when assessed by EMSA-supershift analysis, showed considerable variability under different conditions of exposure. FosB and JunD were the major constituents of AP-1 in both naive and dark-reared animals. Brief visual stimulation (2 hr) added c-Fos, c-Jun, and JunB to this complex, whereas prolonged stimulation (6−24 hr) reduced c-Fos and c-Jun levels significantly, leaving only FosB, JunB, and JunD as the major components of AP-1. These results suggest that transcriptional control by AP-1 may be generated by selective combinatorial interactions of different members of the Fos and Jun families and that are guided by activity-dependent processes.
Systemic Administration of a Nerve Growth Factor Conjugate Reverses Age-Related Cognitive Dysfunction and Prevents Cholinergic Neuron Atrophy
Authors: Bäckman Cristina , Rose Gregory M. , Hoffer Barry J. , Henry Michael A. , Bartus Raymond T. , Friden Phillip , Granholm Ann-Charlotte
Published: April 2018

Intraventricular administration of nerve growth factor (NGF) in rats has been shown to reduce age-related atrophy of central cholinergic neurons and the accompanying memory impairment. Intraventricular administration of NGF is necessary because NGF will not cross the blood–brain barrier (BBB). Here we have used a novel carrier system, consisting of NGF covalently linked to an anti-transferrin receptor antibody (OX-26), to transport biologically active NGF across the BBB. In our experiment, aged (24 months old) Fischer 344 rats received intravenous injections of the OX-26-NGF conjugate or a control solution (a mixture of unconjugated OX-26 and NGF) twice weekly for 6 weeks. The OX-26-NGF injections resulted in a significant improvement in spatial learning in previously impaired rats but disrupted the learning ability of previously unimpaired rats. Neuroanatomical analyses showed that OX-26-NGF conjugate treatment resulted in a significant increase in cholinergic cell size in the medial septal region of rats initially impaired in spatial learning. These results indicate the potential use of the transferrin receptor antibody delivery system for treatment of CNS disorders with neurotrophic proteins.
Trace Eyeblink Conditioning Increases CA1 Excitability in a Transient and Learning-Specific Manner
Authors: Moyer Jr. James R. , Thompson Lucien T. , Disterhoft John F.
Published: April 2018

Time-dependent, learning-related changes in hippocampal excitability were evaluated by recording from rabbit CA1 pyramidal neurons in slices prepared at various times after acquisition of trace eyeblink conditioning. Increased excitability (reduced postburst afterhyperpolarizations and reduced spike-frequency adaptation) was seen as early as 1 hr after acquisition to behavioral criterion, was maximal in neurons studied 24 hr later, and returned to baseline within 7 d, whereas behavioral performance remained asymptotic for months. Neurons were held at −67 mV to equate voltage-dependent effects. No learning-related effects were observed on input resistance, action-potential amplitude or duration, or resting membrane potential. The excitability changes were learning-specific, because they were not seen in neurons from very slow learning (exhibited <30% conditioned responses after 15 training sessions) or from pseudoconditioned control rabbits. Neurons from rabbits that displayed asymptotic behavioral performance after long-term retention testing (an additional training session 14 d after learning) were also indistinguishable from control neurons. Thus, the increased excitability of CA1 neurons was not performance- or memory-dependent. Rather, the time course of increased excitability may represent a critical window during which learning-specific alterations in postsynaptic excitability of hippocampal neurons are important for consolidation of the learned association elsewhere in the brain.
A Spatial Gradient of Tau Protein Phosphorylation in Nascent Axons
Authors: Mandell James W. , Banker Gary A.
Published: April 2018

Mechanisms underlying axonogenesis remain obscure. Although a large number of proteins eventually become polarized to the axonal domain, in no case does protein compartmentalization occur before or simultaneous with the earliest morphological expression of axonal properties. How then might initially unpolarized proteins, such as the microtubule-associated protein tau, play a role in the microdifferentiation of axons? We hypothesized that tau function could be locally regulated by phosphorylation during the period of axonogenesis. To test this hypothesis, we mapped relative levels of tau phosphorylation within developing cultured hippocampal neurons. This was accomplished using calibrated immunofluorescence ratio measurements employing phosphorylation state-dependent and state-independent antibodies. Tau in the nascent axon is more highly dephosphorylated at the site recognized by the tau-1 antibody than tau in the somatodendritic compartment. The change in phosphorylation state from soma to axon takes the form of a smooth proximo-distal gradient, with tau in the soma, immature dendrites and proximal axon ∼80% phosphorylated at the tau-1 site, and that in the axonal growth cone only 20% phosphorylated. The existence of real spatial differences in tau phosphorylation state was confirmed byin situphosphatase and kinase treatment. Pervanadate, a tyrosine phosphatase inhibitor, induced rapid tau dephosphorylation within live cells, effectively abolishing the phosphorylation gradient. Thus, the gradient is dynamic and potentially regulatable by upstream signals involving tyrosine phosphorylation. Phosphorylation gradients are likely to be present on many neuronal proteins in addition to tau, and their modulation by transmembrane signals could direct the establishment of polarity.
α2-Adrenergic Agonists Induce Basic Fibroblast Growth Factor Expression in PhotoreceptorsIn Vivoand Ameliorate Light Damage
Authors: Wen Rong , Cheng Tong , Li Yiwen , Cao Wei , Steinberg Roy H.
Published: April 2018

We observed an induction of basic fibroblast growth factor (bFGF) mRNA in the rat retina after systemic administration of the α2-adrenergic agonists xylazine and clonidine. A single injection of xylazine or clonidine transiently increased bFGF mRNA. Preinjection of yohimbine, an α2-adrenergic antagonist, completely inhibited this increase. Higher dosage of yohimbine inhibited the baseline expression of bFGF. Of particular interest is the finding that the induced bFGF expression occurred almost exclusively in the inner segment region of photoreceptors. No increase in bFGF mRNA was found in the brain after either xylazine or clonidine injection. Xylazine or clonidine given systemically before and during constant light exposure also reduces photoreceptor degeneration in albino rats. These results indicate that regulation of bFGF expression in photoreceptors is unique in the CNS and suggest that endogenous bFGF promotes photoreceptor survival.
Axonal Interactions Regulate Schwann Cell Apoptosis in Developing Peripheral Nerve: Neuregulin Receptors and the Role of Neuregulins
Authors: Grinspan Judith B. , Marchionni Mark A. , Reeves Matthew , Coulaloglou Markella , Scherer Steven S.
Published: April 2018

Programmed cell death during development resulting from the lack of appropriate survival factors has been demonstrated in both neurons and oligodendrocytes and occurs mostly in the form of apoptosis. We now demonstrate that Schwann cells in the rat sciatic nerve undergo apoptosis during early postnatal development and that the amount of apoptosis is markedly increased by axotomy. The apoptotic Schwann cells express the low-affinity nerve growth factor receptor but not myelin-related proteins, indicating that they are in the premyelinating state. Apoptosis resulting from normal development or from axotomy can be inhibited markedly by exogenous neuregulin. Consistent with this, the neuregulin receptor componentserbB2 anderbB3 are expressed and phosphorylated in developing sciatic nerve. These data suggest that Schwann cell number in developing peripheral nerve is regulated by apoptosis through competition for axonally derived neuregulin.
Mitochondrial Dysfunction Is a Primary Event in Glutamate Neurotoxicity
Authors: Schinder Alejandro F. , Olson Eric C. , Spitzer Nicholas C. , Montal Mauricio
Published: April 2018

Excitotoxic neuronal death, associated with neurodegenerative disorders and hypoxic insults, results from excessive exposure to excitatory neurotransmitters. Glutamate neurotoxicity is triggered primarily by massive Ca2+influx arising from overstimulation of the NMDA subtype of glutamate receptors. The underlying mechanisms, however, remain elusive. We have tested the hypothesis that mitochondria are primary targets in excitotoxicity by confocal imaging of intracellular Ca2+([Ca2+]i) and mitochondrial membrane potential (ΔΨ) on cultured rat hippocampal neurons. Sustained activation of NMDA receptors (20 min) elicits reversible elevation of [Ca2+]i. Longer activation (50 min) renders elevation of [Ca2+]iirreversible (Ca2+overload). Susceptibility to NMDA-induced Ca2+overload is increased when the 20 min stimuli are applied to neurons pretreated with electron transport chain inhibitors, thereby implicating mitochondria in [Ca2+]ihomeostasis during excitotoxic challenges. Remarkably, ΔΨ exhibits prominent and persistent depolarization in response to NMDA, which closely parallels the incidence of neuronal death. Blockade of the mitochondrial permeability transition pore by cyclosporin A allows complete recovery of ΔΨ and prevents cell death. These results suggest that early mitochondrial damage plays a key role in induction of glutamate neurotoxicity.
Trophic Effects of Androgen: Receptor Expression and the Survival of Laryngeal Motor Neurons after Axotomy
Authors: Pérez Julio , Kelley Darcy B.
Published: April 2018

To determine whether changes in androgen receptor (AR) expression are associated with trophic actions of androgens, we have examined the laryngeal motor nucleus (N. IX–X) ofXenopus laevis1 and 5 months after section of the laryngeal nerve.In situhybridization was used to recognize cells expressing mRNA for theXenopusAR and bromodeoxyuridine to assess cell proliferation. In addition, the total number of cells was determined in untreated and dihydrotestosterone (DHT)-treated animals after 5 months of axotomy. After 1 month of axotomy, the number of AR mRNA-expressing cells in N. IX–X is 1.8-fold higher than in the intact side. Androgen upregulates expression of AR mRNA in N. IX–X on both the intact and the axotomized sides, suggesting that the increase is independent of contact with muscle. Neither the axotomy- nor the androgen-induced increase in number of cells expressing AR mRNA is attributable to cell proliferation. Five months after axotomy, both the total number of cells and the number of AR mRNA-expressing cells are severely decreased in the axotomized N. IX–X. DHT treatment mitigates the cell loss in N. IX–X induced by prolonged axotomy; the effect includes maintenance of AR mRNA-expressing cells. Gonadally intact males have more cells in the axotomized N. IX–X than castrated animals, suggesting that androgen acts at physiological levels as a trophic hormone. Axotomy-induced upregulation of AR expression may facilitate the trophic actions of androgens.
Evidence for p53-Mediated Modulation of Neuronal Viability
Authors: Xiang Hong , Hochman Daryl W. , Saya Hideyuki , Fujiwara Toshiyoshi , Schwartzkroin Philip A. , Morrison Richard S.
Published: April 2018

A role for p53-related modulation of neuronal viability has been suggested by the finding that p53 expression is increased in damaged neurons in models of ischemia and epilepsy. These findings were recently extended with the demonstration that mice deficient in p53 (“knock-out” mice) exhibit almost complete protection from seizure-induced brain injury, whereas wild-type mice display significant neuronal cell loss in the hippocampus and other brain regions. Because the p53 knock-out mice used in the latter study expressed a global p53 deficiency in all cell types, it was not possible to conclude that protection was conferred by the exclusive absence of p53 in neurons. Therefore, in the present study, we determined whether p53 expression in isolated neurons is directly coupled to a loss of viability associated with excitotoxic challenge. Primary cultures of hippocampal or cortical neurons were derived from animals containing p53 (+/+, +/−) or those deficient in p53 (−/−). p53-Deficient neurons appeared identical to wild-type neurons with respect to morphology, neurofilament expression, and resting levels of intracellular calcium. Neurons containing at least one copy of p53 were severely damaged by exposure to kainic acid or glutamate. Cell damage was assessed by direct cell counting and by nuclear morphology after propidium iodide staining of DNA. In contrast, neurons deficient in p53 (−/−) exhibited little or no damage in response to excitotoxin treatment. Despite their divergent outcomes, p53 (+/+) and p53 (−/−) neurons demonstrated similar sustained elevations in intracellular calcium levels triggered by glutamate exposure. Restoring p53 expression to p53-deficient neurons, using adenovirus-mediated transduction, was sufficient to promote neuronal cell death even in the absence of excitotoxin. These results demonstrate a direct relationship between p53 expression and loss of viability in CNS neurons.
Aggregation of Sodium Channels Induced by a Postnatally Upregulated Isoform of Agrin
Authors: Sharp Andrew A. , Caldwell John H.
Published: April 2018

Agrin is involved in signaling the formation of high concentrations of acetylcholine receptors (AChRs) at the neuromuscular junction (NMJ). There are multiple isoforms of agrin attributable to alternative splicing, and these isoforms are differentially expressed during development and between tissues. The ability to cluster AChRs varies among the agrin isoforms. Sodium channels (NaChs) are also concentrated at the NMJ. We have tested various agrin isoforms for their ability to induce formation of clusters of NaChs. We grew cocultures of dissociated adult rat muscle fibers with chinese hamster ovary (CHO) cells that had been transfected with different isoforms of agrin. Using immunocytochemical techniques, we determined that after 1 d in culture, CHO cells synthesizing the neuronally expressed isoform with an eight amino acid insert (Agrin8) were able to form NaCh clusters at sites of contact between the CHO cell and muscle cell. Clusters of NaChs could be formed anywhere along a muscle fiber, but more clusters were detected close to the endplate where the endogenous level of NaChs was higher. None of the other neuronal-specific agrin isoforms was able to cluster NaChs. Because Agrin8 is the only agrin isoform that is upregulated at birth when NaChs begin to cluster at the NMJ, we conclude that Agrin8 expression by motor neurons is a signal for NaCh clustering at the NMJ during normal development.