Four age groups of Fischer 344 rats (6-, 12-, 18-, and 24-months of age) were compared on a battery of reflexive and locomotor tasks. The simple reflexive tasks such as placing, hopping, negative geotaxis and surface and mid-air righting showed little or no change as a function of age. In contrast, tasks requiring more coordinated control of motor and reflexive responses such as suspension from a horizontal wire, descent of a wire mesh pole, traversal of an elevated platform and rotorod performance showed significant declines with age, with some declines noticeable early in the lifespan. When these results are compared with the results of tasks conducted with infant rats, it is noted that the reflexive and motor skills that emerge early in development are the least affected by the aging process. This observation suggests a first-in, last-out sequence for reflexive and motor behaviors.

Este artigo aborda as finanças comportamentais, uma das inovações mais importantes e controversas em finanças, que confrontam o paradigma tradicionalmente aceito, baseado na moderna teoria financeira. Inicialmente realiza-se uma síntese de potenciais problemas de tomada de decisão, exemplificando-se alguns aspectos não racionais que constituem importantes paradoxos em finanças. Após uma discussão da teoria de prospecto, replicam-se numa amostra brasileira os experimentos seminais de Kahneman e Tversky. São discutidas diversas situações que violam premissas da teoria da utilidade esperada, base da teoria moderna de finanças. Os resultados empíricos mostram que se mantêm as evidências de diversos vieses de percepção em decisões, independentemente de aspectos relacionados com a evolução do mercado e com a cultura ou nacionalidade dos indivíduos. O distanciamento entre a teoria moderna de finanças e a prática em decisões financeiras sugere a abordagem das finanças comportamentais como uma alternativa para explicar o comportamento dos agentes econômicos. PALAVRAS-CHAVE Finanças comportamentais, comportamento do investidor, teoria moderna de finanças, teoria da utilidade esperada, vieses cognitivos. Herbert Kimura Universidade Presbiteriana Mackenzie Leonardo Fernando Cruz Basso Universidade Presbiteriana Mackenzie Elizabeth Krauter FEA-USP ABSTRACT This study discusses the Behavioral Finance, one of the most important and controversial innovations in finance

Short-term and spatial memory were studied in Fischer 344 rats ranging in age from 6 to 26 months of age. Spatial memory, as measured by performance in an 8-armed radial maze, declined gradually with age. In contrast, short-term memory, as measured by retention of previous choices in the spatial maze over short intervals and performance on a modified form of Konorski's discriminated delayed response task, did not decline differentially as a function of age. These findings may be comparable to those obtained in the aged human, who also show marked deficits in spatial memory and little change in primary memory under appropriate test conditions.

No abstract

The Brazilian model of corporate governance is characterized by a highly concentrated ownership structure, which usually culminates in an overlap between ownership and management. According to the literature, the accumulation of shares by the controller(s) can affect corporate performance due to both the alignment (or incentive) effect and the entrenchment effect. At first, the presence of large shareholders is associated with benefits for an organization because it increases the effectiveness of management monitoring. However, very high levels of ownership concentration can allow controllers to dominate the corporation's decision-making process, which could result in the expropriation of wealth from minority shareholders. The relevance of the ownership structure as an internal mechanism of corporate governance motivates the present study. This article aims to test whether ownership and control concentration influences corporate market value. An unbalanced panel was used for the period from 2001 to 2010, composed of 237 Brazilian non-financial publicly traded companies, totaling 1,199 observations. Dynamic regression models were used, estimated by the System Generalized Method of Moments (Sys-GMM), to mitigate possible sources of endogeneity, such as the omission of variables, the feedback effect, and the simultaneity. A quadratic relationship was found between cash flow rights of the largest shareholder and firm market value. Moreover, the results indicate that the corrected market value of the total shares held by the largest shareholder captured the incentive effect, while voting rights concentration captured the entrenchment effect.

Agradeço a Deus por mais esta conquista. Agradeço às minhas filhas, Paula e Bruna, pelo amor, o carinho, a compreensão, a paciência e o apoio constantes. Agradeço ao professor e orientador Dr. Almir Ferreira de Sousa pelo apoio e incentivo na condução do trabalho, além das oportunidades oferecidas para meu desenvolvimento profissional. Agradeço aos professores da banca de qualificação Dr. Eduardo Kazuo Kayo e Dr. José Roberto Ferreira Savoia, pelas importantes contribuições para o desenvolvimento do estudo. Agradeço aos professores do Programa de Pós-Graduação em Administração da FEA-USP pelos ensinamentos transmitidos. Agradeço aos professores da banca do Consórcio Doutoral EnANPAD 2008, Dr. Luiz Eduardo Teixeira Brandão e Dr. Walter Lee Ness Jr, pelas valiosas sugestões para o desenvolvimento desta tese. Agradeço à equipe do Programa de Estudos em Gestão de Pessoas (Progep) da FIA, por ter disponibilizado os dados para a realização do trabalho. Agradeço à equipe da Fundação Instituto de Pesquisas Contábeis, Atuariais e Financeiras (FIPECAFI), em especial, ao Prof. Dr. Ariovaldo dos Santos, por ter disponibilizado importantes informações para a realização da pesquisa. Agradeço ao CNPq pelo apoio financeiro durante o curso de doutorado. Agradeço aos professores Dr. Diógenes de Souza Bido e Dr. Antonio Airton Carneiro de Freitas pela ajuda nos testes estatísticos.

If acoustic startle stimuli are presented in pairs (81-82), then the reaction to the second is reduced, the size of the refractory decrement determined by the interstimulus interval and the relative intensity of Si. If a neutral stimulus (p) is presented just prior to Si, then the reaction to Si is similarly inhibited, revealing the phenomenon of prestimulus inhibition. In 2 experiments we found that suppression of the reflex to 82 by Si was unaffected by prestimulus inhibition of Si, i.e., reflex amplitudes associated with Sa were identical in pS t -S2 series and 81-82 series. In contrast, a reduction in the intensity of Si relative to 82 did reduce the effect of Si on S 2 . These data indicate that prestimulus inhibition of the reflex to Si does not result because the preliminary stimulus attenuates the sensory impact of Si. The inhibitory process may be presumed to have a central locus.

Repeated, isolated presentations of a stimulus typically reduce the subsequent ability of that cue to become an effective conditioned stimulus. This phenomenon is generally referred to as the latent inhibition effect. In this article four experiments are reported that lead to the conclusion that the latent inhibition effect itself can be reduced if repeated presentations of another stimulus are administered prior to preexposing the to-be-conditioned stimulus. The theoretical implications of this finding are discussed in terms of two alternative conceptions. One approached the phenomenon as representing a memory retrieval failure, the other considered the effect to be an instance of a failure in the memory storage processes that normally underlie the latent inhibition effect.If a stimulus has been presented repeatedly prior to being paired with a reinforcer it is retarded, relative to a novel cue, in becoming a signal for either a Pavlovian conditioned reaction or an instrumental response. This phenomenon has received considerable attention and is commonly referred to as the latent inhibition effect (e.g., Lubow, 1973;Lubow & Moore, 1959). Lubow's (1973 review of this literature indicates that researchers have isolated a number of variables that systematically influence the latent inhibition effect. For example, the degree to which a cue will be latently inhibited has been found to increase with the number of presentations prior to conditioning (e.g., Domjan & Siegel, 1971; Lantz, 1973, Exp. 1;Lubow, 1965;Siegel, 1969) and to increase as the duration of the interval separating stimulus presentations is increased (e.g., Lantz, 1973, Exp. 2). Very little is known, however, about how prior exposure to more than one stimulus event influences the latent inhibition effect.