1,258 research outputs found
Monetary policy during Brazil´s Real Plan: estimating the Central Bank´s reaction function
This paper uses a Threshold Autoregressive (TAR) model with exogenous variables to explain a change in regime in Brazilian nominal interest rates. By using an indicator of currency crises -which is chosen endogenously - the model tries to explain the difference in the dynamics of nominal interest rates during and out of a currency crises. The paper then compares the performance of the nonlinear model to a modified Taylor Rule adjusted to Brazilian interest rates, and shows that the former performs considerably better than the latter.
Polyphenols and antioxidant activity in macroalgae from Azores.
International Symposium FloraMac 2010”. Ponta Delgada, Açores, 23-25 de Setembro
INTERANNUAL MORPHOLOGICAL CHANGES OF BOA VIAGEM BEACH - NORTHEAST COAST OF BRAZIL
Boa Viagem and Pina are urban beaches highly economically important both locally and regionally providing protection for the southern coast of Recife, Pernambuco – Brazil. The objective of this paper is to study the interannual morphological changes which occur on these beaches in order to gather information on the erosion processes. For this purpose 6 topographical profiles were monitored, monthly, from August 2002 to December 2005, during spring tide. To establish the position of each profile it was considered whether the beach was protected by reefs, or not, and if there were coastal protection structures. The largest morphological variation was observed in profiles located to the extreme South and North of the area of study (profiles 1 and 5), as well as the profiles located immediately to the North of the coastal protection features (profiles 4A and 4B). Profiles located in the middle of the study area showed stability. As for sedimentary budget the following variations were observed: negative sedimentary budget in profiles P1 (-4.0 m3/m), P4A (-22.0 m3/m), P4B (-7.0 m3/m) and P5 (-1.0 m3/m); positive sedimentary budget in profiles P2 (+2.0 m3/m) and P3 (+4.0 m3/m). Profiles 2 and 3 presented a more consistent budget than those of the profiles located at the extremities of the area (profiles 1, 4A, 4B and 5). The profiles did not present morphologic variations in the beach environment like those mentioned in conventional literature. Profiles 2-1, 3-2 e 4A-3 do not present a linear relation between rates of sedimentary budget. However a positive linear relation between profiles 4B-3 and 5-4B was observed. Variations of accretion and erosion found in this study may be related to seasonal variations in the direction of currents along the coast
Travel of studies: cities of João Pessoa, Maceio, Natal and Recife: a look on the urban space and brazilian architectural production
Ponencia presentada a Session 8: Dimensiones psicosociales de la arquitectura y el urbanismo / Psycological dimensions of architecture and planningThis article aims to present the methodology and the final results of the elective course “Travel of Studies” which belongs to the new pedagogical project from the Architecture and Urbanism course at the University Federal of Pernambuco. It was offered for the first time in 2013.The discipline was organized to occur in four long weekends through visits of four capitals of the Northeast of Brazil: Recife, João Pessoa, Natal and Maceió. The purpose was to allow the students to apprehend the cities through four axis: intervention in historical center (axis 1), production of urban space (axis 2), production of coastline space (axis 3) and contemporary architecture (axis 4). After the four visits were complete, we prepared a poster with the comparison of the cities based on the identification of the similarities and differences of each axis we have studied
Synthesis of heterocyclic compounds by radical electrochemical approach in environmentally friendly media
Radical cyclisation is rapidly becoming an important method for the formation of cyclic systems. Hence, some electrochemical results obtained in the study of electroreductive intramolecular cyclisation of ethyl 2-bromo-3-(3,4-methylenedioxophenyl)-3-(propargyloxy)propanoate (1a), [1-bromo-2-methoxy-2-(prop-2’-ynyloxy) ethyl] benzene (1b) and 1-[2-bromo-2-phenyl-1-(prop-2’-ynyloxy)ethyl]-4-methoxybenzene (1c) promoted by (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetra-decane)nickel(I), [Ni(tmc)]+, electrogenerated at glassy carbon cathodes in ethanol, ethanol / water and microemulsions made with cationic and anionic surfactants are presented. The results obtained indicate that the reaction proceeds via cleavage of the carbon–bromine bond to form a radical intermediate that undergoes cyclization on the unsaturated C-C bond to afford the substituted tetrahydrofurans.Fundação para a Ciência e a Tecnologia (FCT
Reductive intramolecular cyclization of D-glucose-based unsaturated substrates by indirect electrochemical approach in “Green” media
Radical cyclisation continues to be a central methodology for the preparation of natural products containing heterocyclic rings.
Hence, some electrochemical results obtained by cyclic voltammetry and controlled-potential electrolysis in the study of electroreductive intramolecular cyclisation of ethyl (2S, 3R)-2-
bromo-3-propargyloxy-3-(2’,3’,4’,6’-tetra-O-acetyl-β-D-glucopyranosiloxy) propanoate (1) promoted by (1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetra-decane)nickel(I), [Ni(tmc)]+,
electrogenerated at glassy carbon cathodes in ethanol and ethanol/water mixtures containing tetraalkylammonium salts, are
presented.
During controlled-potential electrolyses of solutions containing [Ni(tmc)]2+ and acetylated D-glucose-based bromo propargyl ester (1) catalytic reduction of the latter proceeds via one-electron cleavage of the carbon–bromine bond to form a radical
intermediate that undergoes cyclization to afford the substituted tetrahydrofurans.Fundação para a Ciência e a Tecnologia (FCT
Reactions radicalaires dans des milieux protiques et aprotiques : comparaisons entre les cyclisations reductives electrochimiques catalysees par des complexes du nickel
The electrochemical reductive cyclisation of unsaturated organic halides in the presence of Ni(II) complexes as catalysts was
examined in aprotic solvents such as DMF and in protic solvents such as ethanol, butanol or ethanolewater mixtures. The presence
of the alcohol media enhanced the rate of recycling of the catalytic species.La cyclisation réductive électrochimique d’halogénures insaturés en présence de complexes de Ni(II) comme catalyseurs a été examinée dans des solvants comme le DMF et dans des solvants protiques comme l’éthanol, le butanol ou des mélanges éthanol-eau. La présence du milieu alcoolique augmente la vitesse du recyclage des espèces catalytiques.Fundação para a Ciência e a Tecnologia (FCT
Deficiência de glicose-6-fosfato desidrogenase eritrocitária em recém-nascidos do sexo masculino e sua relação com a icterícia neonatal
Glucose-6-phosphate dehydrogenase (G6PD) deficiency, the commonest red cell enzymopathy in humans, has an X-linked inheritance. The major clinical manifestations are drug induced hemolytic anemia, neonatal jaundice and chronic nonspherocytic hemolytic anemia. The incidence of neonatal hyperbilirubinemia is much greater in G6PD-deficient neonates than babies without this deficiency. The aim of this study was to ascertain the presence of neonatal jaundice in erythrocyte G6PD-deficient male newborns. Samples of umbilical cord blood from a total of 204 male newborns of the Januário Cicco School Maternity located in Natal, Rio Grande do Norte, Brazil were analyzed. The G6PD deficiency was identified by the methemoglobin reduction test (Brewer's test). The deficiency was confirmed by quantitative spectrophotometric assay for enzyme activity and cellulose acetate electrophoresis was used to identify the G6PD variant. Eight newborns were found to be G6PD deficient with four of them exhibiting jaundice during the first 48 hours after birth with bilirubin levels higher than 10 mg/dL. All deficient individuals presented the G6PD A- variant at electrophoresis. Our findings confirmed the association between G6PD deficiency and neonatal jaundice. Hence, early diagnosis of the deficiency at birth is essential to control the appearance of jaundice and to prevent the exposure of these newborns to known hemolytic agents.A deficiência de glicose-6-fosfato desidrogenase (G6PD) é a anormalidade enzimática hereditária mais frequente. É transmitida como caráter recessivo ligado ao cromossomo X e as principais manifestações clínicas são hemólise induzida por fármacos, icterícia neonatal e anemia hemolítica não esferocítica. O objetivo do estudo foi determinar a presença de icterícia neonatal em recém-nascidos do sexo masculino deficientes de glicose-6-fosfato desidrogenase. Foram analisadas 204 amostras de sangue umbilical de recém-nascidos do sexo masculino provenientes da Maternidade Escola Januário Cicco em Natal, Rio Grande do Norte. A deficiência da glicose-6-fosfato desidrogenase foi determinada através do método qualitativo da redução da metahemoglobina (teste de Brewer) e confirmada mediante determinação espectrofotométrica quantitativa da atividade da G6PD e pela eletroforese da enzima em acetato de celulose. Oito recém-nascidos apresentaram deficiência da G6PD, e quatro deles exibiram icterícia nas primeiras 48 horas depois do nascimento, com valores de bilirrubina maiores de 10 mg/dL. Todos os deficientes apresentaram a variante A-. Os dados encontrados confirmam a associação da deficiência da G6PD e a icterícia neonatal. Assim sendo, o diagnóstico precoce da deficiência logo após o nascimento é essencial ao controle do aparecimento da icterícia e para evitar o contato destes recém-nascidos com conhecidos agentes hemolíticos
Development and characterization of a nanomultilayer coating of pectin and chitosan : evaluation of its gas barrier properties and application on 'Tommy Atkins' mangoes
A nanomultilayer coating made of food-grade, bio-based materials (consisting of five nanolayers of pectin and chitosan) was produced. This coating was firstly characterized in terms of the water vapor, oxygen and carbon dioxide permeabilities; these parameters exhibited values of 0.019 ± 0.005 × 10−11, 0.069 ± 0.066 × 10−14 and 44.8 ± 32 × 10−14 g m/(Pa s m2), respectively, and are of the same order of magnitude of those found in other nanomultilayer systems. The nanomultilayer system was applied on whole ‘Tommy Atkins’ mangoes and the layers’ adsorption was confirmed by changes in the contact angle of the coated fruits’ skin. After 45 d of storage, uncoated mangoes presented a higher mass loss, higher total soluble solids and lower titratable acidity in comparison with coated mangoes. Uncoated mangoes had also a damaged and wrinkled appearance, showing evidence of microbial spoilage, and the flesh exhibited a slightly brownish color, in comparison with the coated mangoes. These results suggest a positive effect of the coating on gas flow reduction and on the consequent extension of the shelf-life of mangoes.The author Bartolomeu G.S. Medeiros was recipient of a scholarship from de Project Isac (Isac Mundus Cooperation, European Union) and is also a recipient of a scholarship from Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (Capes, Brazil). The author Ana C. Pinheiro is recipient of a fellowship (SFRH/BD/48120/2008) from the Fundacao para a Ciencia e Tecnologia (FCT, Portugal). The present work was supported by CAPES/PROCAD/NF/1415/2007
Electrosynthesis of nitrogen heterocycles using environmentally friendly methodologies
Cyclic voltammetry and constant-current electrolysis in a one-compartment cell with a sacrificial anode
has been used to study the indirect electroreduction of N-allyl- -haloamides by electrogenerated Ni(I)
complexes conducted inN,N-dimethylformamide (DMF) and acetonitrile (ACN) and the resultswere compared
with those obtained in protic solvents such as EtOH and EtOH–H2O mixtures. It was observed that
the indirect electrochemical reduction of N-allyl- -haloamides led to the corresponding lactams and the
yields and selectivities obtained in EtOH and EtOH–H2O were much better than those obtained in DMF
or ACN.Fundação para a Ciência e a Tecnologia (FCT
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