Superação da alienação dos alunos para a realização da leitura crítica

This article aims to present the possibilities of an educational practice that focuses on the formation of Basic Education students in critical readers. For this, understand the concepts of alienation and language from the point of view of Historical and Dialectical Materialism and Historical-Cultural Theory was essential to understand how the students of the 7th year are able to overcome this paradigm that contributes to the naive reading of texts worked in the classroom. It was a qualitative study of bibliographic revision in union with the dialectical practice with students in a public school located in the north of the State of Paraná. As methodology, was developed twelve classes with diversified material in which the teacher's mediation sought to contemplate form and content in the way that occurred the deconstruction of the fictitious hero concept represented at the end by the art of the haicai poem. The use of the cell phone instrument and Whatsapp were important for the development of the poetic sense. It seeks, therefore, to demonstrate the contributions of historical and dialectical materialism to teaching practice and human development. The theorists considerations allow us to note that language contributes to the development of higher psychic functions in man and the alienation of subjects in today's society considerably affects the students interpretation and, consequently, formation for critical reading, which can be overcome with the use of a conscious theoretical current.El Objetivo en este artículo es presentar las posibilidades de una práctica educativa que se centra en la formación de estudiantes de Educación Básica en lectores críticos. Por lo tanto, la comprensión de los conceptos de alienación y el lenguaje desde la perspectiva del materialismo histórico y dialéctico y la teoría histórico-cultural son esenciales para ver cómo los estudiantes de 7º grado son capaces de superar este paradigma que contribuye a la lectura ingenua de los textos trabajado en el aula. Este fue un estudio cualitativo de la revisión de la literatura en unión con la práctica dialéctica con los estudiantes en una escuela pública ubicada en el norte del estado de Paraná. La metodología fue desarrollada con doce clases con diversos materiales en los que la mediación del maestro solicita a contemplar la forma y el contenido de lo que le ocurrió a deshacer el concepto de héroe de ficción con el uso del arte de haikai. El uso del instrumento móvil y WhatsApp fueron importantes para el desarrollo del sentido poético. Las actividades muestran las contribuciones del materialismo histórico y dialéctico para la práctica de la enseñanza y el desarrollo humano. Las consideraciones determinan que el lenguaje contribuye al desarrollo de las funciones psíquicas superiores del hombre y de la alienación de los individuos en la sociedad de hoy en día que afecta en gran medida la interpretación de los estudiantes y, en consecuencia, la formación para la lectura crítica, que puede ser superada con el uso de una corriente teórica consciente.Objetiva-se neste artigo apresentar as possibilidades de uma prática educativa que tem como foco o formar alunos da Educação Básica em leitores críticos. Para tanto, compreender os conceitos de alienação e de linguagem sob a ótica do Materialismo Histórico e Dialético e da Teoria Histórico-Cultural foram essenciais para perceber como os alunos de um 7º ano são capazes de superar este paradigma que contribui para a leitura ingênua dos textos trabalhados em sala de aula. Tratou-se de um estudo qualitativo de revisão bibliográfica em união com a prática dialética com alunos em uma escola pública situada no norte do Estado de Paraná. Como metodologia foram desenvolvidas doze aulas com material diversificado nas quais a mediação do docente buscou contemplar forma e conteúdo de maneira que ocorresse a desconstrução do conceito de herói fictício representado ao final pela arte do poema haicai. O uso do instrumento celular e whatsapp foram importantes para o desenvolvimento do senso poético. Busca-se, portanto, demonstrar as contribuições do materialismo histórico e dialético para a prática docente e o desenvolvimento humano. As considerações dos teóricos permitem constatar que a linguagem contribui para o desenvolvimento das funções psíquicas superiores no homem e que a alienação dos sujeitos na sociedade atual afeta consideravelmente a interpretação dos alunos e, consequentemente, a formação para a leitura crítica, que pode ser superada com o uso de uma corrente teórica consciente

FORMACIÓN EN INVESTIGACIÓN PEDAGÓGICA PARA DOCENTES UNIVERSITARIOS. PROPUESTA DE UNA ESTRATEGIA

This article is born of the Dynamic investigation of the process of formation of the pedagogic investigation of the educational ones of superior education", carried out by the author in option to Doctor's title in Pedagogic Sciences. The end is to present the conception of a formation strategy in pedagogic investigation for the educational of the University of Guayaquil, Ecuador. The investigation was developed by means of the systemic-structural-functional method with pedagogic focus starting from assuming like center the formative process as essential element and the complexity of the same one, subject to multiple educational, social and cultural influences that offer him a dynamic and complex character, starting from that which, you power the active character of the entirety of the community of educational, as an essential aspect to achieve transformation processes in pedagogic investigation.  Este artículo nace de la investigación “Dinámica del proceso de formación de la investigación pedagógica de los docentes de educación superior”, realizada por la autora en opción al título de Doctor en Ciencias Pedagógicas. El fin es presentar la concepción de una estrategia de formación en investigación pedagógica para los docentes de la Universidad de Guayaquil, Ecuador. La investigación se desarrolló mediante el método sistémico-estructural-funcional con enfoque pedagógico a partir de asumir como centro el proceso formativo como elemento esencial y la complejidad del mismo, sujeto a múltiples influencias educativas, sociales y culturales que le ofrecen un carácter dinámico y complejo, a partir de lo cual, se potencia el carácter activo de la totalidad del colectivo de docentes, como un aspecto esencial para lograr procesos de transformación en investigación pedagógica

Derivativos sobre commodities influenciam a volatilidade dos preços à vista? uma análise nos mercados de boi gordo e café arábica no Brasil

The bullish movement in commodity prices during the 2000s can be explained based on structural and conjectural factors. In addition, it was argued that this price movement was amplified by the contagion from the derivative markets. In this context, these contracts were one of the aspects responsible for an increase in cash price volatility. Thus, this paper evaluated the influence of trading activity (volume and open interest) and futures price volatility in spot price volatility for arabica coffee and live cattle in Brazilian markets. Granger causality tests, forecast error variance decomposition, considering vector autoregression models, and tests of causality in variance, based on the cross-correlation function and on the idea of Lagrange multiplier were conducted. The results showed that, during the period considered, in most cases, an unexpected movement in trading volume and variability of futures prices changed the pattern of spot price volatility.Além de fatores conjunturais da economia mundial e estruturais relativos à oferta e demanda global por commodities, aponta-se que o movimento altista dos preços destes produtos na década de 2000 pode também ser explicado pelo maior contágio dos derivativo523417436sem informaçãosem informaçãoAdrangi, B., Chatrath, A., Futures commitments and exchange rate volatility (1998) Journal of Business Finance and Accounting, 25 (3), pp. 501-520Ahmad, H., Shah, S.Z.A., Shah, I.A., Impact of Futures Trading on Spot Price Volatility: Evidence from Pakistan (2010) International Research Journal of Finance and Economics, 59, pp. 145-165Alexakis, P., On the effect of index futures trading on stock market volatility (2007) International Research Journal of Finance and Economics, 11, pp. 7-20Antoniou, A., Foster, A.J., The effect of futures trading on spot price volatility: Evidence for Brent crude oil using GARCH (1992) Journal of Business Finance and Accounting, 19 (4), pp. 473-484Antoniou, A., Holmes, P., Futures trading, information and spot price volatility: Evidence for the FTSE-100 Stock Index Futures contract using GARCH (1995) Journal of Banking & Finance, 19 (1), pp. 117-129Antoniou, A., Holmes, P., Priestley, R., The effects on stock index futures trading on stock index volatility: An analysis of the asymmetric response of volatility to news (1998) The Journal of Futures Market, 18 (2), pp. 151-166Bae, S.C., Kwon, T.H., Park, J.W., Derivatives trading, volatility spillover, and regulation: Evidence from the Korean securities markets (2009) The Journal of Futures Markets, 29 (6), pp. 563-597Bandivadekar, S., Ghosh, S., Derivatives and volatility on Indian stock markets (2003) Reserve Bank of India Occasional Papers, 24 (3), pp. 1-15Bessembinder, H., Seguin, P., Futures trading activity and stock price volatility (1992) Journal of Finance, 47 (5), pp. 2015-2034Bessembinder, H., Chan, H., Seguin, P., An empirical examination of information, differences of opinion, and trading activity (1996) Journal of Financial Economics, 40 (1), pp. 105-134Board, J., Sandmann, G., Sutcliffe, C., The effect of futures market volume on spot market volatility (2001) Journal of Business Finance & Accounting, 28 (7-8), pp. 799-819Bollerslev, T., Generalized autoregressive conditional heteroscedasticity (1986) Journal of Econometrics, 31 (3), pp. 307-327Bologna, P., Cavallo, L., Does the introduction of stock index futures effectively reduce stock market volatility? Is the 'futures effect' immediate? Evidence from the Italian stock exchange using GARCH (2002) Applied Financial Economics, 12 (3), pp. 183-192Brorsen, B.W., Oellermann, C.M., Farris, P.L., The live cattle futures market and daily cash price movements (1989) The Journal of Futures Markets, 9 (4), pp. 273-282Brown, C.J., Curci, R., Mexican peso futures and exchange rate volatility (2002) Latin American Business Review, 3 (1), pp. 75-90Chatrath, A., Ramchander, S., Song, F., The role of futures trading activity in exchange rate volatility (1996) The Journal of Futures Markets, 16 (5), pp. 561-584Cheung, Y.W., Ng, L.K., A causality in variance test and its application to financial market prices (1996) Journal of Econometrics, 72, pp. 33-48Clifton, E.V., The currency futures market and interbank foreign exchange trading (1985) The Journal of Futures Markets, 5 (3), pp. 375-384Cox, C.C., Futures trading and market information (1976) Journal of Political Economy, 84 (6), pp. 1215-1237Dawson, P., Staikouras, S.K., The impact of volatility derivatives on S&P 500 volatility (2009) The Journal of Futures Markets, 29 (12), pp. 1190-1213Debasish, S.S., Effect of futures trading on spot-price volatility: Evidence for NSE Nifty using GARCH (2009) The Journal of Risk Finance, 10 (1), pp. 67-77Drimbetas, E., Sariannidis, N., Porfiris, N., The effect of derivatives trading on volatility of the underlying asset: Evidence from the Greek stock market (2007) Applied Financial Economics, 17 (2), pp. 139-148Emery, H.C., (1896) Speculation on the stock and produce exchanges of the United States, , Columbia University, New YorkEngle, R.F., Autoregressive conditional heteroscedasticity with estimates of the variance of United Kingdom inflation (1982) Econometrica, 50 (4), pp. 987-1007Figlewski, S., Futures trading and volatility in the GNMA market (1981) Journal of Finance, 36, pp. 445-456Galvão, A.B., Portugal, M.S., Ribeiro, E.P., Volatilidade e causalidade: evidências para o mercado à vista e futuro de índice de ações no Brasil (2000) Revista Brasileira de Economia, 54 (1), pp. 37-56Garcia, P., Leuthold, R.M., Zapata, H., Leadlag relationships between trading volume and price variability: new evidence (1986) The Journal of Futures Markets, 6 (1), pp. 1-10Gray, R.W., Onions revisited (1963) Journal of Farm Economics, 65 (2), pp. 273-276Hafner, C.M., Herwartz, H., A Lagrange multiplier test for causality in variance (2006) Economics Letters, 93, pp. 137-141Hegde, S.P., The impact of futures trading on the spot market for treasury bonds (1994) Financial Review, 29 (4), pp. 441-471Hooker, R.H., The suspension of the Berlin produce exchange and its effect upon corn prices (1901) Journal of the Royal Statistical Society, 64 (4), pp. 574-604Illueca, M., Lafuente, J.A., The effect of spot and futures trading on stock index market volatility: A nonparametric approach (2003) The Journal of Futures Markets, 23 (9), pp. 841-858Illueca, M., Lafuente, J.A., Introducing the mini-futures contract on Ibex 35 implications for price discovery and volatility transmission (2008) Spanish Economic Review, 10 (3), pp. 197-219Jensen, G.R., Johnson, R.R., Mercer, J.M., Tactical asset allocation and commodity futures (2002) Journal of Portfolio Management, 28 (4), pp. 100-111Jochum, C., Kodres, L., Does the introduction of futures on emerging market currencies destabilize the underlying currencies? (1998) IMF Staff Papers, 45 (3), pp. 486-521Johnson, A.C., (1973) Effects of futures trading on price performance in the cash onion market, 1930-68, , Washington: U.S. Department of Agriculture, Technical Bulletin n° 1470Kasman, A., Kasman, S., The impact of futures trading on volatility of the underlying asset in the Turkish stock market (2008) Physica A: Statistical Mechanics and its Applications, 387 (12), pp. 2837-2845Kocagil, A.E., Does futures speculation stabilize spot prices? Evidence from metals markets (1997) Applied Financial Economics, 7, pp. 115-125Kocagil, A.E., Shachmurove, Y., Return -Volume dynamics in futures markets (1998) The Journal of Futures Markets, 18 (4), pp. 399-426Malliaris, A.G., Urrutia, J.L., Volume and price relationships: hypotheses and testing for agricultural futures (1998) The Journal of Futures Markets, 18 (1), pp. 53-72Mayhew, S., The impact of derivatives on cash markets: what have we learned? Working paper, Department of Banking and Finance, Terry College of Business (2000) University of GeorgiaMorgan, C.W., Futures markets and spot price volatility: A case study (1999) Journal of Agricultural Economics, 50 (2), pp. 247-257Moriarty, E.J., Tosini, P.A., Futures trading and the price volatility of GNMA certificates-further evidence (1985) The Journal of Futures Markets, 5 (4), pp. 633-641Netz, J.S., The effect of futures markets and corners on storage and spot price variability (1995) American Journal of Agricultural Economics, 77 (1), pp. 182-193Peck, A.E., Reflections of hedging on futures market activity (1979) Food Research Institute Studies, 17 (3), pp. 327-349Phillips, P.C.B., Perron, P., Testing for a unit root in time series regression (1988) Biometrika, 75, pp. 335-346Pilar, C., Rafael, S., Does derivatives trading destabilize the underlying assets? Evidence from the Spanish stock market (2002) Applied Economics Letters, 9 (2), pp. 107-110Pok, W.C., Poshakwale, S., The impact of futures contracts on the spot market volatility: The case of Kuala Lumpur Stock Exchange (2004) Applied Financial Economics, 14 (2), pp. 143-154Powers, M.J., Does futures trading reduce price fluctuations in the cash markets? (1970) American Economic Review, 60 (3), pp. 460-464Rao, R., Impact of financial derivative products on spot market volatility: A study of Nifty (2007) The ICFAI Journal of Derivatives Market, 4 (1), pp. 7-16Redrado, M., Carrera, J., Bastourre, D., Ibarlucía, J., Financialization of commodity markets: Nonlinear consequences from heterogeneous agent behavior (2009), Working Paper 44, Banco Central de la República ArgentinaRyoo, H.-J., Smith, G., The impact of stock index futures on the Korean stock market (2004) Applied Financial Economics, 14 (4), pp. 243-251Santos, J., Did futures markets stabilize US grain price? (2002) Journal of Agricultural Economics, 53 (1), pp. 25-36Shastri, K., Sultan, J., Tandon, K., The impact of the listing of options in the foreign exchange market (1996) Journal of International Money and Finance, 15 (1), pp. 37-64Spyrou, S.I., Index futures trading and spot price volatility (2005) Journal of Emerging Market Finance, 4 (2), pp. 151-167Srinivasan, P., Bhat, K.S., The impact of futures trading on the spot market volatility of selected commercial banks in India (2008) European Journal of Economics, Finance and Administrative Sciences, (14), pp. 28-40Staikouras, S.K., Testing the stabilization hypothesis in the UK short-term interest rates: evidence from a GARCH-X model (2006) Quarterly Review of Economics and Finance, 46 (2), pp. 169-189Stein, J., Informational externalities and welfarereducing speculation (1987) Journal of Political Economy, 95, pp. 1123-1145Taylor, G.S., Leuthold, R.M., The influence of futures trading on cash cattle price variations (1974) Food Research Institute Studies, 13 (1), pp. 29-35Thraen, C.S., The emerging futures market for cheddar cheese: A mechanism for stability or increased spot-price volatility? (1998) Proceedings of the NCR-134 Conference on Applied Commodity Price Analysis, , Forecasting, and Market Risk Management, Chicago, ILTomek, W.G., A note on historical wheat prices and futures trading (1971) Food Research Institute Studies, 110 (1), pp. 109-113Tripathy, N., Rao, S.V.R., Kanagaraj, A., Impact of derivatives trading on spot market volatility: An empirical study (2009) International Journal of Applied Decision Sciences, 2 (2), pp. 209-232The financialization of commodity markets (2009) Trade and Development Report, , United Nations, New York and Geneva(2007) A cadeia da carne bovina no Brasil: Uma análise de poder de mercado e teoria da informação, , Tese apresentada à Escola de Economia de São Paulo, Fundação Getúlio Vargas, FGV-SPWeaver, R.D., Banerjee, A., Does futures trading destabilize cash prices? Evidence for U,S, live beef cattle (1990) The Journal of Futures Markets, 10 (1), pp. 41-60Working, H., Price effects of futures trading (1960) Food Research Institute Studies, 1 (1), pp. 3-31Wray, L.R., O novo capitalismo dos gerentes de dinheiro e a crise financeira global (2009) Oikos, 8 (1), pp. 19-39Yang, J., Balyeat, R.B., Leatham, D.J., Futures trading activity and commodity cash price volatility (2005) Journal of Business Finance & Accounting, 32 (1-2), pp. 297-323Zhong, M., Darrat, A.F., Otero, R., Price discovery and volatility spillovers in index futures markets: Some evidence from Mexico (2004) Journal of Banking & Finance, 28 (12), pp. 3037-3054The bullish movement in commodity prices during the 2000s can be explained based on structural and conjectural factors. In addition, it was argued that this price movement was amplified by the contagion from the derivative markets. In this context, thes

A LITERATURA COMO ATIVIDADE INVESTIGATIVA PARA A SUPERAÇÃO DO COTIDIANO

A pesquisa é um recorte da dissertação do Mestrado em Educação, no qual a autora investiga as contribuições da Literatura e o uso dos gêneros textuais para a leitura crítica dos estudantes do Ensino Fundamental fase II. A base teórica que fundamenta o trabalho é o Materialismo Histórico e Dialético. Os participantes são alunos do 8º e 9º anos de três instituições públicas de ensino da região norte do Paraná. Após o trabalho em sala de aula com projetos de intervenção em leitura, elaborados pelos integrantes do projeto OBEDUC/UEL Educação, os alunos foram convidados a ler um poema e identificar os diferentes determinantes presentes no discurso do texto e justificar criticamente suas escolhas. Percebe-se na análise dos testes de leitura crítica que os alunos possuem uma leitura ingênua do poema, apesar da identificação dos principais determinantes no texto

Derivativos sobre commodities influenciam a volatilidade dos preços à vista? Uma análise nos mercados de boi gordo e café arábica no Brasil

sem informaçãoAlém de fatores conjunturais da economia mundial e estruturais relativos à oferta e demanda global por commodities, aponta-se que o movimento altista dos preços destes produtos na década de 2000 pode também ser explicado pelo maior contágio dos derivativo523417436sem informaçãosem informaçãosem informaçã

Shiga toxin-producing Escherichia coli O157, O26 and O111 in cattle faeces and hides in Italy

Introduction: Ruminants are regarded as the natural reservoir for Shiga toxin-producing Escherichia coli (STEC), especially of serogroup O157. Materials and methods: During 2011 and 2012, 320 samples (160 faecal samples from the rectum and 160 hide samples from the brisket area) were collected from 160 cattle at slaughter in Northern Italy during warm months (May to October). Cattle were reared in different farms and their age at slaughter ranged between nine months and 15 years, most of them being culled cattle (median age: six years; average age: 4.6 years). Samples were tested by immunomagneticseparation technique for E coli O157 and O26 and by a screening PCR for stx genes followed by cultural detection of STEC. The virulence genes stx1, stx2, eae, and e-hlyA were detected and among stx2-positive isolates the presence of the stx2a and stx2c variants was investigated. Results: Twenty-one of 160 cattle (13.1 per cent; 95 per cent CI 8.3 to 19.4 per cent) were found to be faecal carriers of STEC. STEC O157 was found in 10 (6.3 per cent) samples, STEC O26 in six (3.8 per cent) and STEC O111 in one (0.6 per cent). Four isolates (2.5 per cent) were O not determined (OND). Six out of 160 (3.8 per cent; 95 per cent CI 1.4 to 8.0 per cent) hide samples were positive for STEC; four hides (2.5 per cent) were contaminated by STEC O157 and two (1.3 per cent) by STEC O26. In three cattle (1.9 per cent) STEC from both faeces and hides were detected. Among STEC O157, 87.5 per cent of them carried the stx2c gene and 12.5 per cent carried both stx1 and stx2c genes. No O157 isolate harboured stx2a variant. STEC O26 and O111 carried the stx1 gene only. One OND strain carried both the stx2a and stx2c genes. Conclusions: This study shows that STEC O157 from cattle can harbour the stx2c variant, which is associated with haemolytic uraemic syndrome in humans, and that cattle hides may be a source of human pathogenic STEC O157 and O26 in the slaughterhouse environment

LEITURA DE CHARGES: um Projeto de intervenção para o ensino de Geografia na Educação Básica

RESUMO: O objetivo deste artigo é o demonstrar como foi elaborado e aplicado um projeto de intervenção relacionados à leitura de charges para o ensino de geografia em uma instituição de ensino pública do Estado do Paraná. A investigação teve como base os índices educacionais do IDEB (Índice de Desenvolvimento da Educação Básica) e as análises das notas alcançadas pelos alunos na Prova Brasil em Língua Portuguesa. A investigação parte leitura de charges pelos alunos no intuito de verificar se os mesmos conseguem identificar nas imagens as diferentes dimensões, tais como: políticas, econômicas, sociais, culturais, religiosas, que contribuem para a apropriação de conceitos geopolíticos e também para a formação de leitores críticos capazes de desvelar as intencionalidades dos discursos nas diferentes mídias que os cercam. A base teórico-metodológica para a análise dos resultados da pesquisa é o Materialismo Histórico e Dialético, pois se entende a leitura como modo de transformação social. A investigação serve como justificativa para a formulação e implantação de projetos de intervenção em leitura com charges no intuito de contribuir para a leitura crítica de textos, pois os resultados apresentados demonstraram que os alunos não conseguem identificar as intencionalidades dos discursos presentes nas imagens apresentadas. Palavras-chave: Leitura de charges. Geografia. Materialismo Histórico Dialético. Projeto de Intervenção

Apreçamento de opções sobre taxa de câmbio R/US/US negociadas no Brasil: uma comparação entre os modelos Black e redes neurais artificiais

In this study, a multilayer neural network model was applied to the pricing of R/USD exchange rate call options traded on the São Paulo Securities, Commodities and Futures Exchange (BM&FBovespa) from January 2004 to December 2007. Based on the actual market prices, the performances of a neural network model and the Black model were compared, using the usual error metrics and statistical tests. Overall, the results showed that the artificial intelligence model outperformed the Black model for the different degrees of moneyness.En este estudio se aplicó un modelo de red neuronal multicapa para la valoración de opciones de compra sobre el tipo de cambio R/US, cotizadas en la Bolsa de Valores, Mercadorias e Futuros (BM&FBovespa), para el período comprendido entre enero de 2004 y diciembre de 2007. A partir de los precios efectivamente practicados en el mercado, se comparó el desempeño entre las redes neuronales y el modelo de Black, con el uso de métricas habituales de error y pruebas estadísticas. Los resultados mostraron, en general, la mejor adecuación del modelo de inteligencia artificial, en comparación con el modelo de Black, en diferentes grados de monetización.No estudo aqui apresentado, aplicou-se um modelo de rede neural multicamadas para o apreçamento de calls sobre taxa de câmbio R/US$, negociadas na Bolsa de Valores, Mercadorias & Futuros de São Paulo (BM&FBovespa), para o período de janeiro de 2004 a dezembro de 2007. A partir dos preços efetivamente praticados no mercado, comparou-se o desempenho entre essa técnica e o modelo de Black, utilizando-se métricas usuais de erro e testes estatísticos. Os resultados obtidos revelaram, em geral, a melhor adequação do modelo de inteligência artificial, em comparação ao modelo de Black, nos diferentes graus de moneyness

Impacto dos contratos futuros do Ibovespa na volatilidade dos índices de ações no Brasil: uma análise na crise do subprime

CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOSignificant increasing in derivatives trading over the world markets has led to an interesting debate about futures contracts influences on spot prices. In this context, this paper aims to evaluate, during the subprime crisis, the influence of IBOVESPA futures price volatility on the spot price indices as follows: IBOVESPA, FGV-100, IBrX-50, IGC, SMLL and MLCX. We considered the period from August 2007 to April 2009, when the evidence of the crisis were intense until to be recovering of growth of stock market index. To assess causality-in-variance, tests proposed by Cheung and Ng (1996) and Hafner and Herwartz (2006) were employed, and the volatility was estimated by an univariate GARCH process. It was found that the volatility of IBOVESPA futures contract did not destabilize spot indices during the subprime crisis.O aumento das negociações de derivativos no mercado mundial tem levado a um amplo debate acerca da influência dos contratos futuros sobre os preços à vista em diferentes mercados. Neste contexto, o presente artigo teve por objetivo avaliar, no período da crise do subprime, a influência da volatilidade dos preços futuros do IBOVESPA sobre os seguintes índices à vista: IBOVESPA, FGV-100, IBrX-50, IGC, SMLL e MLCX. Considerou-se o período entre agosto de 2007 e abril de 2009, quando as evidências da crise foram mais intensas até a retomada de crescimento dos índices acionários. Para se avaliar a causalidade na variância, foram empregados testes propostos por Cheung e Ng (1996) e Hafner e Herwartz (2006), sendo a volatilidade estimada por um processo GARCH univariado. Os resultados levaram à rejeição da hipótese de que, durante a crise do subprime, os movimentos do mercado futuro desestabilizaram o mercado à vista de ações brasileiro.O aumento das negociações de derivativos no mercado mundial tem levado a um amplo debate acerca da influência dos contratos futuros sobre os preços à vista em diferentes mercados. Neste contexto, o presente artigo teve por objetivo avaliar, no período da crise do subprime, a influência da volatilidade dos preços futuros do IBOVESPA sobre os seguintes índices à vista: IBOVESPA, FGV-100, IBrX-50, IGC, SMLL e MLCX. Considerou-se o período entre agosto de 2007 e abril de 2009, quando as evidências da crise foram mais intensas até a retomada de crescimento dos índices acionários. Para se avaliar a causalidade na variância, foram empregados testes propostos por Cheung e Ng (1996) e Hafner e Herwartz (2006), sendo a volatilidade estimada por um processo GARCH univariado. Os resultados levaram à rejeição da hipótese de que, durante a crise do subprime, os movimentos do mercado futuro desestabilizaram o mercado à vista de ações brasileiro424801825CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOSignificant increasing in derivatives trading over the world markets has led to an interesting debate about futures contracts influences on spot prices. In this context, this paper aims to evaluate, during the subprime crisis, the influence of IBOVESPA futures price volatility on the spot price indices as follows: IBOVESPA, FGV-100, IBrX-50, IGC, SMLL and MLCX. We considered the period from August 2007 to April 2009, when the evidence of the crisis were intense until to be recovering of growth of stock market index. To assess causality-in-variance, tests proposed by Cheung and Ng (1996) and Hafner and Herwartz (2006) were employed, and the volatility was estimated by an univariate GARCH process. It was found that the volatility of IBOVESPA futures contract did not destabilize spot indices during the subprime crisi