Immigration and memory

The town of Nova Friburgo, in Brazil, was founded in 1820 by swiss immigrants who, as often happens in the majority of migratory flows, crossed the ocean in search of better life conditions. The scope of this paper is to trail the path of a swiss immigrant called Marianne Joset Salusse and then follow on to investigate the mechanisms involved in elaborating family memory and public memory around this woman who would become a symbol of immigration to this town. Thus a series of interviews were held with her descendants, which were fundamental for the understanding of current representations and the main elements which constitute the collective memory around Marianne. Besides oral sources, we had recourse to written documents which allowed a retrieval of relevant information about her life. More than simply adding information, written sources allowed for a more profound analysis of oral accounts, unravelling as well as unveiling selective procedures peculiar to memory construction (Pollak, 1989;1992).

Money versus memory

A well–established fact in monetary theory is that a key ingredient for the essentiality of money is its role as a form of memory. In this paper we study a notion of memory that includes information about an agent’s past actions and trading opportunities but, in contrast to Kocherlakota (1998), does not include information about the past actions and trading opportunities of an agent’s past partners. We first show that the first–best can be achieved with memory even if it only includes information about an agent’s very recent past. Thus, money can fail to be essential even if memory is minimal. We then establish, more interestingly, that if information about trading opportunities is not part of an agent’s record, then money can be better than memory. This shows that the societal benefit of money lies not only on being a record of past actions, but also on being a record of past trading opportunities, a fact that has been overlooked by the monetary literature.

The aliasing effect, the Fejer Kernel and temporally aggregated long memory processes

This paper derives the spectral density function of aggregated long memory processes in light of the aliasing effect. The results are different from previous analyses in the literature and a small simulation exercise provides evidence in our favour. The main result point to that flow aggregates from long memory processes shall be less biased than stock ones, although both retain the degree of long memory. This result is illustrated with the daily US Dollar/ French Franc exchange rate series.

The private memory of aggregate shocks

We study constrained efficient aggregate risk sharing and its consequence for the behavior of macro-aggregates in a dynamic Mirrlees’s (1971) setting. Privately observed idiosyncratic productivity shocks are assumed to be independent of i.i.d. publicly observed aggregate shocks. Yet, private allocations display memory with respect to past aggregate shocks, when idosyncratic shocks are also i.i.d.. Under a mild restriction on the nature of optimal allocations the result extends to more persistent idiosyncratic shocks, for all but the limit at which idiosyncratic risk disappears, and the model collapses to a pure heterogeneity repeated Mirrlees economy identical to Werning [2007]. When preferences are iso-elastic we show that an allocation is memoryless only if it displays a strong form of separability with respect to aggregate shocks. Separability characterizes the pure heterogeneity limit as well as the general case with log preferences. With less than full persistence and risk aversion different from unity both memory and non-separability characterize optimal allocations. Exploiting the fact that non-separability is associated with state-varying labor wedges, we apply a business cycle accounting procedure (e.g. Chari et al. [2007]) to the aggregate data generated by the model. We show that, whenever risk aversion is great than one our model produces efficient counter-cyclical labor wedges.

Convex combinations of long memory estimates from different sampling rates

Convex combinations of long memory estimates using the same data observed at different sampling rates can decrease the standard deviation of the estimates, at the cost of inducing a slight bias. The convex combination of such estimates requires a preliminary correction for the bias observed at lower sampling rates, reported by Souza and Smith (2002). Through Monte Carlo simulations, we investigate the bias and the standard deviation of the combined estimates, as well as the root mean squared error (RMSE), which takes both into account. While comparing the results of standard methods and their combined versions, the latter achieve lower RMSE, for the two semi-parametric estimators under study (by about 30% on average for ARFIMA(0,d,0) series).

Forecasting electricity demand using generalized long memory

This paper studies the electricity hourly load demand in the area covered by a utility situated in the southeast of Brazil. We propose a stochastic model which employs generalized long memory (by means of Gegenbauer processes) to model the seasonal behavior of the load. The model is proposed for sectional data, that is, each hour’s load is studied separately as a single series. This approach avoids modeling the intricate intra-day pattern (load profile) displayed by the load, which varies throughout days of the week and seasons. The forecasting performance of the model is compared with a SARIMA benchmark using the years of 1999 and 2000 as the out-of-sample. The model clearly outperforms the benchmark. We conclude for general long memory in the series.

Temporal aggregation and bandwidth selection in estimating long memory

This paper reinterprets results of Ohanissian et al (2003) to show the asymptotic equivalence of temporally aggregating series and using less bandwidth in estimating long memory by Geweke and Porter-Hudak’s (1983) estimator, provided that the same number of periodogram ordinates is used in both cases. This equivalence is in the sense that their joint distribution is asymptotically normal with common mean and variance and unity correlation. Furthermore, I prove that the same applies to the estimator of Robinson (1995). Monte Carlo simulations show that this asymptotic equivalence is a good approximation in finite samples. Moreover, a real example with the daily US Dollar/French Franc exchange rate series is provided.

Uma arca das tradições: educar e comemorar no Museu Mariano Procópio

Esta tese é uma reflexão sobre a construção de escritas da História do Brasil em museus, a partir da década de 1920, momento fulcral para o estabelecimento de uma “pedagogia da nacionalidade” republicana, que tem por suporte o discurso museal. Alguns dos esforços político-pedagógicos dessas instituições foram observados, com o objetivo de compreender as principais características de um paradigma educativo para o saber histórico nos museus. Assim, a análise das comemorações cívicas, dos guias de divulgação e das exposições permitiu uma aproximação das ativações memoriais ensejadas pelos atores dos museus, com atenção para as continuidades, as negociações e as transformações dos projetos, especialmente em sua dimensão pedagógica. O Museu Mariano Procópio foi selecionado para a realização de um estudo de caso, tanto por suas especificidades, que nos induzem a pensar o “concerto” dos museus nacionais a partir do interior do país como pela relevância de seu acervo e pela intensidade de ações educativas desenvolvidas na gestão de Geralda Armond (1944-1980). A gestão Armond é o foco da tese, sendo marcada pela defesa da continuidade institucional e do enquadramento da memória da família Lage; pela luta pela sustentação material do Museu, inclusive com uma forte aproximação com o regime civil e militar; e pela busca da profissionalização de quadros e do dinamismo das ações. Os resultados atentam para a multiplicidade e fragilidade na construção identitária do Museu, associada ao fato de ser um museu “municipal”. Uma situação que explica, ao menos em parte, seu esquecimento no cenário nacional a despeito de seu acervo expressivo e das articulações encetadas com o sistema escolar, por meio do fortalecimento do sentido cívico de suas ações pedagógicas.

O teatro de Viriato Corrêa: uma escrita da História para o povo brasileiro

O presente trabalho tem como objetivo analisar a atuação de intelectuais entendidos como mediadores culturais, ou seja, aqueles que têm como objetivo a divulgação de conhecimento histórico para o grande público. Para tanto, escolhemos como objeto de estudo o intelectual Viriato Corrêa (1884-1967), que entendemos ser exemplar nesse tipo de atuação intelectual. Mais especificamente, buscaremos nos ater às suas peças teatrais, escritas entre as décadas de 1910 e 1940, que, como todo o resto de sua obra, são marcadas por um intenso discurso de valorização do nacional. É preciso lembrar que o período em questão é estratégico no que concerne à construção de uma identidade nacional republicana. Assim, buscaremos demonstrar como o escritor contribuiu e esteve engajado no projeto de construção de uma história e memória nacionais através de suas produções teatrais, utilizando-as como vetores culturais de difusão de uma história de cunho cívico-patriótico.

A história e a memória a nos guiar no Rio de Janeiro: proposta para um guia de viagem

A presente dissertação propõe-se a trazer algumas reflexões sobre o turismo cultural no Rio de Janeiro através da criação de um guia de viagem com rotas temáticas baseadas na história da cidade. Este guia proporia novas formas de leitura da paisagem urbana carioca a partir do papel central que a cidade teve na história brasileira enquanto capital política e cultural da nação. O foco principal dos itinerários seria a fase republicana no Brasil entre o final do século XIX até os anos 1970. Nesse período, o Rio passou por uma série de reformas urbanas que seriam também analisadas através de uma série de caminhadas temáticas descritas no guia. A partir dessa abordagem, o trabalho analisa as possibilidades de formatação desse produto turístico através da interlocução entre referenciais teóricos de Memória Coletiva, Lugar de Memória, Identidade Cultural e Interpretação de Patrimônio. Tirando proveito desses conceitos, o estudo procura justificar esse estilo emergente de turismo cultural como um incentivo para o morador do Rio tornar-se viajante em sua própria cidade, enquanto turista-cidadão.

Spectral properties of temporally aggregated long memory processes

This paper derives the spectral density function of aggregated long memory processes in light of the aliasing effect. The results are different from previous analyses in the literature and a small simulation exercise provides evidence in our favour. The main result point to that flow aggregates from long memory processes shall be less biased than stock ones, although both retain the degree of long memory. This result is illustrated with the daily US Dollar/ French Franc exchange rate series.

Understanding the critical distance in sparse distributed memory

Modelos de tomada de decisão necessitam refletir os aspectos da psi- cologia humana. Com este objetivo, este trabalho é baseado na Sparse Distributed Memory (SDM), um modelo psicologicamente e neuro- cientificamente plausível da memória humana, publicado por Pentti Kanerva, em 1988. O modelo de Kanerva possui um ponto crítico: um item de memória aquém deste ponto é rapidamente encontrado, e items além do ponto crítico não o são. Kanerva calculou este ponto para um caso especial com um seleto conjunto de parâmetros (fixos). Neste trabalho estendemos o conhecimento deste ponto crítico, através de simulações computacionais, e analisamos o comportamento desta “Critical Distance” sob diferentes cenários: em diferentes dimensões; em diferentes números de items armazenados na memória; e em diferentes números de armazenamento do item. Também é derivada uma função que, quando minimizada, determina o valor da “Critical Distance” de acordo com o estado da memória. Um objetivo secundário do trabalho é apresentar a SDM de forma simples e intuitiva para que pesquisadores de outras áreas possam imaginar como ela pode ajudá-los a entender e a resolver seus problemas.

A Mismatch-Based Model for Memory Reconsolidation and Extinction in Attractor Networks

OSAN, R. , TORT, A. B. L. , AMARAL, O. B. . A mismatch-based model for memory reconsolidation and extinction in attractor networks. Plos One, v. 6, p. e23113, 2011.

Increased hippocampal excitability and impaired spatial memory function in mice lacking VGLUT2 selectively in neurons defined by tyrosine hydroxylase promoter activity

Three populations of neurons expressing the vesicular glutamate transporter 2 (Vglut2) were recently described in the A10 area of the mouse midbrain, of which two populations were shown to express the gene encoding, the rate-limiting enzyme for catecholamine synthesis, tyrosine hydroxylase (TH).One of these populations (‘‘TH– Vglut2 Class1’’) also expressed the dopamine transporter (DAT) gene while one did not ("TH–Vglut2 Class2"), and the remaining population did not express TH at all ("TH-Vglut2-only"). TH is known to be expressed by a promoter which shows two phases of activation, a transient one early during embryonal development, and a later one which gives rise to stable endogenous expression of the TH gene. The transient phase is, however, not specific to catecholaminergic neurons, a feature taken to advantage here as it enabled Vglut2 gene targeting within all three A10 populations expressing this gene, thus creating a new conditional knockout. These knockout mice showed impairment in spatial memory function. Electrophysiological analyses revealed a profound alteration of oscillatory activity in the CA3 region of the hippocampus. In addition to identifying a novel role for Vglut2 in hippocampus function, this study points to the need for improved genetic tools for targeting of the diversity of subpopulations of the A10 area

Modeling and Experimental Aspects of Self-healing Bolted Joint through Shape Memory Alloy Actuators

Bolted joints are a form of mechanical coupling largely used in machinery due to their reliability and low cost. Failure of bolted joints can lead to catastrophic events, such as leaking, train derailments, aircraft crashes, etc. Most of these failures occur due to the reduction of the pre-load, induced by mechanical vibration or human errors in the assembly or maintenance process. This article investigates the application of shape memory alloy (SMA) washers as an actuator to increase the pre-load on loosened bolted joints. The application of SMA washer follows a structural health monitoring procedure to identify a damage (reduction in pre-load) occurrence. In this article, a thermo-mechanical model is presented to predict the final pre-load achieved using this kind of actuator, based on the heat input and SMA washer dimension. This model extends and improves on the previous model of Ghorashi and Inman [2004, "Shape Memory Alloy in Tension and Compression and its Application as Clamping Force Actuator in a Bolted Joint: Part 2 - Modeling," J. Intell. Mater. Syst. Struct., 15:589-600], by eliminating the pre-load term related to nut turning making the system more practical. This complete model is a powerful but complex tool to be used by designers. A novel modeling approach for self-healing bolted joints based on curve fitting of experimental data is presented. The article concludes with an experimental application that leads to a change in joint assembly to increase the system reliability, by removing the ceramic washer component. Further research topics are also suggested.