Os determinantes macroeconômicos da estrutura a termo das taxas de juros em dólar no Brasil

Este trabalho propõe o desenvolvimento de um modelo de três fatores em que os movimentos da Estrutura a Termo da Taxa de Juros em Dólar, o Cupom Cambial, são determinados por variáveis macroeconômicas observáveis. O estudo segue a metodologia elaborada por Huse (2011), que propõe um modelo baseado nos estudos de Nelson e Siegel (1987) e Diebold e Li (2006). Os fatores utilizados são: taxa de câmbio em real por dólar, spread do Credit Default Swap (CDS) Brasil de cinco anos, índice de preço de commodities, taxa de cupom cambial futura com vencimento em três meses, taxa futura de juros em dólar com cupom zero (Libor), volatilidade implícita da taxa de câmbio esperada pelo mercado de hoje até um ano, e inflação implícita de um ano no Brasil. O modelo foi capaz de explicar 95% das mudanças na estrutura a termo do cupom cambial. Aumentos no spread do CDS, na taxa de cupom cambial de três meses, na Libor, no índice de preço de commodities, e na volatilidade implícita do câmbio com vencimento em um ano estão diretamente relacionados com aumento na curva de juros em dólar. Por sua vez, a depreciação cambial tem correlação positiva com as maturidades mais curtas, até 2.5 anos, e negativo com a parte longa, até cinco anos. Choques na inflação implícita têm um pequeno impacto positivo para vencimentos curtos, mas levemente negativo para vencimentos mais longos.

Estudo da eficiência reprodutiva de búfalos (Bubalus bubalis) na Amazônia Oriental

Foram avaliados os dados de 1983 a 2005 de cinco rebanhos bubalinos das raças Jafarabadi, Murrah, Mediterrâneo, Carabao e Tipo Baio, bem como seus mestiços. Estudaram-se as características reprodutivas: Idade à Primeira Cria (IPC), Intervalo de Partos (IDP), Eficiência Reprodutiva (ER), Fertilidade Real Adaptada (FRA), Produtividade ao Primeiro Parto Adaptada (PPPA) e Produtividade Acumulada Adaptada (PACA). A média geral encontrada, não ajustada, para IPC foi de 1052,52 ± 120,45 dias (34,7 meses), com valor mínimo e máximo de 737 e 1271 dias, respectivamente, com um coeficiente de variação de 10,32%. O grau de sangue da fêmea e o ano do parto apresentaram efeito significativo (P<0,0001) sobre a idade ao primeiro parto. Para o IEP, a média geral encontrada, não ajustada, foi de 399,69 ± 23,78 dias ou 13,17 meses com um coeficiente de variação de 5,88%. Não foi observada influência significativa das fontes de variação (grau de sangue da fêmea, ano do parto e estação do parto) nos interpartos. A média geral encontrada, não ajustada, para ER, foi de 91,09 ± 1,89% com um coeficiente de variação de 2,05%. Não foi observada influência significativa das fontes de variação (grau de sangue da fêmea, ano do parto e estação do parto) na ER do rebanho. A FRA média encontrada, não ajustada, foi 29,30 ± 4,40 quilogramas de bezerro parido por ano, com valor mínimo e máximo de 0,99 e 44,27 quilogramas de bezerro parido por ano, respectivamente, com um coeficiente de variação de 11,89%. Dentre os fatores que afetam a FRA do rebanho estudado, o grau de sangue da fêmea e o ano do parto mostraram influência significativa (P<0,0001) constituindo-se, portanto, como fontes de variação para essa característica. Para a PPPA, a média geral encontrada, não ajustada, foi de 33,75 ± 6,89 quilogramas, com valor mínimo e máximo de 10 e 62 quilogramas, respectivamente, com um coeficiente de variação de 10,20%. Dentre os fatores que afetaram a PPPA do rebanho estudado, somente o ano do parto mostrou influência significativa (P<0,0001) constituindo-se, portanto, como fonte de variação para essa característica. No que diz respeito a PACA, a média geral encontrada, não ajustada, foi de 22,86 ± 6,55 quilogramas de bezerro parido por ano, com valor mínimo e máximo de 2,08 e 55,35 quilogramas de bezerro parido por ano, respectivamente, com um coeficiente de variação de 6,55%. Dentre os fatores que afetaram a PACA do rebanho estudado, o grau de sangue da fêmea e o ano do parto mostraram influência significativa (P<0,0001) constituindo-se, portanto, como fontes de variação para essa característica. Os parâmetros reprodutivos avaliados neste estudo mostraram-se dentro de uma variação compatível com a observada na literatura pertinente. De maneira geral, verificou-se influência do ano de parto, grau de sangue e grau de sangue da fêmea sobre as características estudadas, o que indica que tais efeitos devem ser levados em consideração na avaliação e seleção dos animais. Os índices produtivos utilizados mostraram-se de grande valia para a seleção, devendo ser melhor estudadas suas interações para com o desempenho geral do rebanho.

Construction of Equivalent Circuit of a Single and Isolated Transformer Winding From FRA Data Using the ABC Algorithm

This paper reports the results of employing an artificial bee colony search algorithm for synthesizing a mutually coupled lumped-parameter ladder-network representation of a transformer winding, starting from its measured magnitude frequency response. The existing bee colony algorithm is suitably adopted by appropriately defining constraints, inequalities, and bounds to restrict the search space and thereby ensure synthesis of a nearly unique ladder network corresponding to each frequency response. Ensuring near-uniqueness while constructing the reference circuit (i.e., representation of healthy winding) is the objective. Furthermore, the synthesized circuits must exhibit physical realizability. The proposed method is easy to implement, time efficient, and problems associated with the supply of initial guess in existing methods are circumvented. Experimental results are reported on two types of actual, single, and isolated transformer windings (continuous disc and interleaved disc).

Construction of Equivalent Circuit of a Single and Isolated Transformer Winding From FRA Data Using the ABC Algorithm

This paper reports the results of employing an artificial bee colony search algorithm for synthesizing a mutually coupled lumped-parameter ladder-network representation of a transformer winding, starting from its measured magnitude frequency response. The existing bee colony algorithm is suitably adopted by appropriately defining constraints, inequalities, and bounds to restrict the search space and thereby ensure synthesis of a nearly unique ladder network corresponding to each frequency response. Ensuring near-uniqueness while constructing the reference circuit (i.e., representation of healthy winding) is the objective. Furthermore, the synthesized circuits must exhibit physical realizability. The proposed method is easy to implement, time efficient, and problems associated with the supply of initial guess in existing methods are circumvented. Experimental results are reported on two types of actual, single, and isolated transformer windings (continuous disc and interleaved disc).

A critical review of the definition of FRA resonance frequency of transformers as per IEEE Std C57.149-2012

The explanation of resonance given in IEEE Std C57.149-2012 to define resonance during frequency response analysis (FRA) measurements on transformers implicitly uses the conditions prevalent during resonance in a series R-L-C circuit. This dependence is evident from the two assertions made in the definition, viz., resulting in zero net reactive impedance, and, accompanied by a zero value appearing in the phase angle of the frequency response function. These two conditions are satisfied (at resonance) only in a series R-L-C circuit and certainly not in a transformer, as has been assumed in the Standard. This can be proved by considering a ladder-network model. Circuit analysis of this ladder network reveals the origin of this fallacy and proves that, at resonance, neither is the ladder network purely resistive and nor is the phase angle (between input voltage and input current) always zero. Also, during FRA measurements, it is often seen that phase angle does not traverse the conventional cyclic path from +90 degrees to -90 degrees (or vice versa) at all resonant frequencies. This peculiar feature can also be explained using pole-zero maps. Simple derivations, simulations and experimental results on an actual winding are presented. In summary, authors believe that this study dispels existing misconceptions about definition of FRA resonance and provides material for its correction in IEEE Std C57.149-2012. (C) 2014 Elsevier B.V. All rights reserved.

Seasonal presence of acicular calcium oxalate crystals in the cambial zone of Citharexylum myrianthum (Verbenaceae)

This study focuses on the seasonal presence of acicular crystals in the cambial zone of Citharexylum myrianthum Chain. (Verbenaceae). Specimens collected in different months from 1996 to 2000 were examined for the abundance of acicular crystals in the cambium. This information was correlated with the phenology of the species and the climate of the region. Acicular calcium oxalate crystals were found in cambial fusiform and ray cell initials, as well as in their daughter cells. An abundance of crystals was observed during periods of water deficit and leaf fall (July). Fewer crystals were found in the beginning of the wet season and bud swelling (September). When trees were flowering and the soil was wet (November and December), acicular crystals were rarely observed. During this period, acicular crystals were found in differentiating phloem and xylem parenchyma cells, in fully differentiated phloem cells, but not in fully differentiated xylem cells.

Ahmedabad | Laboratorio di architettura moderna Il National Institute of Design (1961-68) fra contatti internazionali ed echi della tradizione

Oggetto della ricerca è lo studio del National Institute of Design (NID), progettato da Gautam Sarabhai e sua sorella Gira, ad Ahmedabad, assunta a paradigma del nuovo corso della politica che il Primo Ministro Nehru espresse nei primi decenni del governo postcoloniale. Obiettivo della tesi è di analizzare il fenomeno che unisce modernità e tradizione in architettura. La modernità indiana, infatti, nacque e si sviluppò con i caratteri di un Giano bifronte: da un lato, la politica del Primo Ministro Nehru favorì lo sviluppo dell’industria e della scienza; dall’altro, la visione di Gandhi mirava alla riscoperta del locale, delle tradizioni e dell’artigianato. Questi orientamenti influenzarono l’architettura postcoloniale. Negli anni ‘50 e ’60 Ahmedabad divenne la culla dell’architettura moderna indiana. Kanvinde, i Sarabhai, Correa, Doshi, Raje trovarono qui le condizioni per costruire la propria identità come progettisti e come intellettuali. I motori che resero possibile questo fermento furono principalmente due: una committenza di imprenditori illuminati, desiderosi di modernizzare la città; la presenza ad Ahmedabad, a partire dal 1951, dei maestri dell’architettura moderna, tra cui i più noti furono Le Corbusier e Kahn, invitati da quella stessa committenza, per la quale realizzarono edifici di notevole rilevanza. Ad Ahmedabad si confrontarono con forza entrambe le visioni dell’India moderna. Lo sforzo maggiore degli architetti indiani si espresse nel tentativo di conciliare i due aspetti, quelli che derivavano dalle influenze internazionali e quelli che provenivano dallo spirito della tradizione. Il progetto del NID è uno dei migliori esempi di questo esercizio di sintesi. Esso recupera nella composizione spaziale la lezione di Wright, Le Corbusier, Kahn, Eames ibridandola con elementi della tradizione indiana. Nell’uso sapiente della struttura modulare e a padiglione, della griglia ordinatrice a base quadrata, dell’integrazione costante fra spazi aperti, natura e architettura affiorano nell’edificio del NID echi di una cultura millenaria.

John Ronald Reuel Tolkien fra critica e traduzione: Il caso della history of Middle-Earth

Il progetto si propone di tradurre parti di un’opera di John Ronald Reuel Tolkien inedita in Italia. Si tratta dell'introduzione e di un capitolo del settimo volume della History of Middle-Earth, che raccoglie l’intero corpus degli scritti tolkeniani e ne ricostruisce l’evoluzione narrativa. La tesi, oltre al capitolo dedicato alla traduzione dall'inglese all'italiano e alla discussione delle scelte traduttive, include: alcune notizie biografiche su Tolkien, con particolare riferimento agli anni giovanili; una discussione sulla legittimità di un suo eventuale inserimento all'interno dei canoni letterari; una discussione sulle differenti interpretazioni de Il Signore degli Anelli; una discussione sui contenuti di tutti i volumi della History e sulle difficoltà che sorgono nella traduzione delle opere di Tolkien.

Effect of repetitiveness on the immunogenicity and antigenicity of Trypanosoma cruzi FRA protein

Repetitive proteins (RP) of Trypanosoma cruzi are highly present in the parasite and are strongly recognized by sera from Chagas' disease patients. Flagelar Repetitive Antigen (FRA), which is expressed in all steps of the parasite life cycle, is the RP that displays the greatest number of aminoacids per repeat and has been indicated as one of the most suitable candidate for diagnostic test because of its high performance in immunoassays. Here we analyzed the influence of the number of repeats on the immunogenic and antigenic properties of the antigen. Recombinant proteins containing one, two, and four tandem repeats of FRA (FRA1, FRA2, and FRA4, respectively) were obtained and the immune response induced by an equal amount of repeats was evaluated in a mouse model. The reactivity of specific antibodies present in sera from patients naturally infected with T. cruzi was also assessed against FRA1, FRA2, and FRA4 proteins, and the relative avidity was analyzed. We determined that the number of repeats did not increase the humoral response against the antigen and this result was reproduced when the repeated motifs were alone or fused to a non-repetitive protein. By contrast, the binding affinity of specific human antibodies increases with the number of repeated motifs in FRA antigen. We then concluded that the high ability of FRA to be recognized by specific antibodies from infected individuals is mainly due to a favorable polyvalent interaction between the antigen and the antibodies. In accordance with experimental results, a 3D model was proposed and B epitope in FRA1, FRA2, and FRA4 were predicted.

Cloning and characterization of the genes involved in cambial growth in response to elevated [CO2]

Aspen (Populus tremuloides) trees growing under elevated [CO2] at a free-air CO2 enrichment (FACE) site have produced significantly more biomass compared to control trees. The molecular mechanisms underlying the observed increase in biomass productivity was investigated by producing transcriptomic profiles of the vascular cambium zone (VCZ) and leaves, followed by a comparative study to identify genes and pathways that showed significant changes following long-term exposure to elevated [CO2]. This study is mainly to verify if genetic modification of a few selected candidate genes including CAP1, CKX6, and ASML2 that are expressed in vascular cambium in response to elevated [CO2] can cause the changes in plant growth and development. To this end, these three genes were cloned into both sense and antisense constructs. Then antisense and sense transgenic lines of above-mentioned genes were developed. 15 events were generated for 5 constructs, which were confirmed with regular PCR and RT-PCR. Confirmed plants were planted in greenhouse for growth and phenotypic characterization. The expression of CAP1, CKX6 and ASML2 in antisense plants was measured by real-time RT-PCR, and the changes caused by gene interference in cambial growth were studies by analyzing the microscopic sections made from the antisense transgenic plants. It has been found that 1) CAP1 is mainly expressed in xylem and root. 2) RNAi suppression of CAP1 significantly affected height and diameter. 3) CAP1, ASML2 and CKX6 affected xylem and phloem cell proliferation and elongation. Due to the delay in regenerating sense transgenic plants, the characterization of sense transgenic plants is limited to growth only.

Evaluation of the applicability of FRA for inter-turn fault detection in stator windings

In this paper, the applicability of the FRA technique is discussed as a method for detecting inter-turn faults in stator windings. Firstly, this method is tested in an individual medium-voltage stator coil with satisfactory results. Secondly, the tests are extended to a medium-voltage induction motor stator winding, in which inter-turn faults are performed in every coil end of one phase. Results of the frequency response in case of inter-turn faults are evaluated in both cases for different fault resistance values. The experimental setup is also described for each experiment. The results of the application of this technique to the detection of inter-turn faults justify further research in optimizing this technique for preventive maintenance.

Antitumor promotion by phenolic antioxidants: inhibition of AP-1 activity through induction of Fra expression.

Induction of phase 2 detoxification enzymes by phenolic antioxidants can account for prevention of tumor initiation but cannot explain why these compounds inhibit tumor promotion. Phase 2 genes are induced through an antioxidant response element (ARE). Although the ARE resembles an AP-1 binding site, we show that the major ARE binding and activating protein is not AP-1. Interestingly, AP-1 DNA binding activity was induced by the phenolic antioxidant tert-butylhydroquinone (BHQ), but the induction of AP-1 transcriptional activity by the tumor promoter 12-O-tetradecanoylphorbol 13-acetate (TPA) was inhibited by this compound. BHQ induced expression of c-jun, junB, fra-1, and fra-2, which encode AP-1 components, but was a poor inducer of c-fos and had no effect on fosB. Like c-Fos and FosB, the Fra proteins heterodimerize with Jun proteins to form stable AP-1 complexes. However, Fra-containing AP-1 complexes have low transactivation potential. Furthermore, Fra-1 repressed AP-1 activity induced by either TPA or expression of c-Jun and c-Fos. We therefore conclude that inhibitory AP-1 complexes composed of Jun-Fra heterodimers, induced by BHQ, antagonize the transcriptional effects of the tumor promoter TPA, which are mediated by Jun-Fos heterodimers. Since AP-1 is an important mediator of tumor promoter action, these findings may explain the anti-tumor-promoting activity of phenolic antioxidants.

The signors of the night; the story of Frá Giovanni, the soldier-monk of Venice; and of others in the "Silent city",

Mode of access: Internet.