Comparison between the complete Bayesian method and empirical Bayesian method for ARCH models using Brazilian financial time series

In this work we compared the estimates of the parameters of ARCH models using a complete Bayesian method and an empirical Bayesian method in which we adopted a non-informative prior distribution and informative prior distribution, respectively. We also considered a reparameterization of those models in order to map the space of the parameters into real space. This procedure permits choosing prior normal distributions for the transformed parameters. The posterior summaries were obtained using Monte Carlo Markov chain methods (MCMC). The methodology was evaluated by considering the Telebras series from the Brazilian financial market. The results show that the two methods are able to adjust ARCH models with different numbers of parameters. The empirical Bayesian method provided a more parsimonious model to the data and better adjustment than the complete Bayesian method.

Ucides cordatus cordatus (Linnaeus, 1763) (Crustacea, Decapoda): complete larval development under laboratory conditions and its systematic position

Six zoeal stages and the megalopa of the comestible crab Ucides cordatus cordatus (Linnaeus, 1763) are described and illustrated. The larvae were reared in the laboratory at temperature 25 ± 1ºC and water salinity of 24 ; duration of stages and survival rates were measured. Comparisons with the descriptions of the zoeal morphologic characters of Ocypodidae and Gecarcinidae permited to include definitively U. c. cordatus in the family Ocypodidae, subfamily Ocypodinae.

Avaliação da diversidade genética entre acessos de mamoneira (Ricinus communis L.) por meio de caracteres morfoagronômicos

A divergência genética é um dos mais importantes parâmetros avaliados por melhoristas de plantas na fase inicial de um programa de melhoramento genético. O objetivo deste trabalho foi caracterizar 15 acessos de mamoneira por meio de caracteres morfoagronômicos. O experimento foi conduzido em Lavras, MG, no período de fevereiro a agosto de 2008. O delineamento experimental foi o de blocos ao acaso, com três repetições, e 25 plantas por parcela. Os caracteres avaliados foram: altura da planta, altura do caule, número de internódios, diâmetro do caule e número de racemos. Verificou-se a ocorrência de diferenças significativas pelo teste de F (P < 0,01), para o efeito de acessos para todas as variáveis estudadas. Foram estimadas as distâncias genéticas entre os acessos pelo método euclidiano. de acordo com o agrupamento, utilizando o método de Tocher e o método Hierárquico do Vizinho Mais Próximo, baseado na distância euclidiana houve a formação de quatro grupos distintos. Com base nos resultados obtidos neste trabalho, recomendam-se os cruzamentos entre acessos dos grupos I e IV, II e IV, e III e IV.

Genetic linkage map of chicken chromosome 1 from a Brazilian resource population

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Complete atrioventricular block during renal transplantation in a patient with Alport's syndrome: case report

CONTEXTO: A síndrome de Alport é responsável por aproximadamente 5% dos pacientes com insuficiência renal crônica. Nessa doença, anormalidades no sistema de condução cardíaco são mais freqüentes que na população em geral. OBJETIVO: Relatar caso de síndrome de Alport que desenvolveu bloqueio atrioventricular total durante um transplante renal. RELATO DE CASO: Paciente masculino, 21 anos de idade, com insuficiência renal crônica secundária à síndrome de Alport, foi submetido a transplante renal sob anestesia peridural. Durante o procedimento anestésico-cirúrgico apresentou bloqueio atrioventricular total, que foi tratado rapidamente, e com sucesso, usando-se um marcapasso transcutâneo. O bloqueio simpático extenso pode contribuir para o desenvolvimento de distúrbios no sistema de condução cardíaco, particularmente em pacientes com insuficiência renal crônica em esquema de diálise. Mesmo em pacientes com eletrocardiograma pré-operatório normal e sem distúrbios de condução, graus variáveis de bloqueio atrioventricular, incluindo bloqueio atrioventricular total, podem ocorrer. Nesse caso, o uso de marcapasso transcutâneo é tratamento rápido e efetivo na sala de operação até o final da cirurgia, quando o tratamento definitivo pode ser planejado.

EVOLUTION OF ADENINE CLUSTERING IN 5S RIBOSOMAL-RNA

The frequency of adenine mononucleotides (A), dinucleotides (AA) and clusters, and the positions of clusters, were studied in 502 molecules of the 5S rRNA.All frequencies were reduced in the evolutive lines of vertebrates, plants and fungi, in parallel with increasing organismic complexity. No change was observed in invertebrates. All frequencies were increased in mitochondria, plastids and mycoplasmas. The presumed relatives to the ancestors of the organelles, Rhodobacteria alfa and Cyanobacteria, showed intermediate values, relative to the eubacterial averages. Firmibacterid showed very high number of cluster sites.Clusters were more frequent in single-stranded regions in all organisms. The routes of organelles and mycoplasmas accummulated clusters at faster rates in double-stranded regions. Rates of change were higher for AA and clusters than for A in plants, vertebrates and organeltes, higher for cluster sites and A in mycoplasmas, and higher for AA and A in fungi. These data indicated that selection pressures acted more strongly on adenine clustering than on adenine frequency.It is proposed that AA and clusters, as sites of lower informational content. have the property of tolerating positional variation in the sites of other molecules (or other regions of the same molecule) that interact with the adenines. This reasoning was consistent with the degrees of genic polymorphism. low in plants and vertebrates and high in invertebrates. In the eubacteria endosymbiontic or parasitic to eukaryotes, the more tolerant RNA would be better adapted to interactions with the homologous nucleus-derived ribosomal proteins: the intermediate values observed in their precursors were interpreted as preadaptive.Among other groups, only the Deinococcus-Thermus eubacteria showed excessive AA and cluster contents, possibly related to their peculiar tolerance to mutagens, and the Ciliates showed excessive AA contents, indicative of retention of primitive characters.

Kinesiographic study of deglutition in dentate individuals and complete denture wearers

Swallowing is used as a clinical method in prosthodontics to determine and record jaw relationships. The aim of this study was to perform a quantitative evaluation, in naturally dentate subjects and complete denture wearers, of three measurements associated with the mandibular position during the act of swallowing water: 1. intermaxillary distance on vertical axis; 2. anteroposterior deviation; and 3. lateral deviation. Two groups were selected: Group I (GI) included 40 subjects with complete dentition (mean age 45.27 yrs) and Group II (GII) included 40 bimaxillary edentate subjects, complete denture wearers (mean age 63.92 yrs). A kinesiographic instrument was used for analysis. Three records were taken for each measurement and a mean value obtained. It was concluded that: 1. intermaxillary distance on vertical axis and horizontal deviation were similar for both groups; 2. there was a significant intermaxillary distance on the vertical axis; and 3. for anteroposterior and lateral axis, results showed moderate deviation in relation to maximal intercuspation (MI).

Clustering of rare earth in glasses, aluminum effect: experiments and modeling

Luminescent spectra of Eu3+-doped sol-gel glasses have been analyzed during the densification process and compared according to the presence or not of aluminum as a codoping ion. A transition temperature from hydrated to dehydroxyled environments has been found different for doped and codoped samples. However, only slight modifications have been displayed from luminescence measurements beyond this transition. To support the experimental analysis, molecular dynamics simulations have been performed to model the doped and codoped glass structures. Despite no evidence of rare earth clustering reduction due to aluminum has been found, the modeled structures have shown that the luminescent ions are mainly located in aluminum-rich domains. The synthesis of both experimental and numerical analyses has lead us to interpret the aluminum effect as responsible for differences in structure of the luminescent sites rather than for an effective dispersion of the rare earth ions. (C) 2004 Elsevier B.V. All rights reserved.

Comparative investigation of the cleavage step in the synthesis of model peptide resins: Implications for N-alpha-9-fluorenylmethyloxycarbonyl-solid phase peptide synthesis

Based on our studies of the stability of model peptide-resin linkage in acid media, we previously proposed a rule for resin selection and a final cleavage protocol applicable to the N-alpha-tert-butyloxycarbonyl (Boc)-peptide synthesis strategy. We found that incorrect choices resulted in decreases in the final synthesis yield, which is highly dependent on the peptide sequence, of as high as 30%. The present paper continues along this line of research but examines the N-alpha-9-fluorenylmethyloxycarbonyl (Fmoc)-synthesis strategy. The vasoactive peptide angiotensin II (All, DRVYIHPF) and its [Gly(8)]-All analogue were selected as model peptide resins. Variations in parameters such as the type of spacer group (linker) between the peptide backbone and the resin, as well as in the final acid cleavage protocol, were evaluated. The same methodology employed for the Boc strategy was used in order to establish rules for selection of the most appropriate linker-resin conjugate or of the peptide cleavage method, depending on the sequence to be assembled. The results obtained after treatment with four cleavage solutions and with four types of linker groups indicate that, irrespective of the circumstance, it is not possible to achieve complete removal of the peptide chains from the resin. Moreover, the Phe-attaching peptide at the C-terminal yielded far less cleavage (50-60%.) than that observed with the Gly-bearing sequences at the same position (70-90%). Lastly, the fastest cleavage occurred with reagent K acid treatment and when the peptide was attached to the Wang resin.

Structure, mobility and clustering of interstitial O in La2CuO4+delta in the limit of small delta

Anelastic spectra (elastic energy absorption as a function of temperature) are reported which provide evidence that excess O in La2CuO4+delta starts forming two different types of defects already at very low concentrations, where no phase separation or changes in the type of O intercalation are believed to occur. The absorption peak with the lowest activation enthalpy, H/k(B) = 5600 K, is visible at lowest values of delta and is attributed to the hopping of single interstitial O2- ions. The second process, with a slightly slower dynamics, appears at higher values of delta and soon becomes preponderant over the former process. The latter process is proposed to be due to stable pairs of O atoms and is put in connection with the formation of partially covalent bonds between interstitial and apical oxygen; such bonds would reduce the doping efficiency of excess O at increasing delta. The geometry of the interstitial O defect is discussed. O 1998 Published by Elsevier B.V. B.V. All rights reserved.

Comparison of accuracy between compression- and injection-molded complete dentures

Statement of problem. A clinically significant incisal pin opening may occur after processing complete dentures if a compression molding technique is used. To recover the proper vertical dimension of occlusion, a time-consuming occlusal adjustment is necessary that often destroys the anatomy of the artificial teeth. A new injection molding process claims to produce dentures that require few, if any, occlusal adjustments in the laboratory after processing.Purpose. This laboratory study compared incisal pin opening, dimensional accuracy, and laboratory working time for dentures fabricated by this new injection system with dentures constructed by the conventional compression molding technique.Material and methods. Two groups of 6 maxillary and 6 mandibular dentures were evaluated as follows: group 1 (control), Lucitone 199, compression molded with a long cure cycle; and group 2, Lucitone 199, injection molded with a long cure. Incisal pin opening was measured with a micrometer immediately after deflasking. A computerized coordinate measuring machine was used to measure dimensional accuracy of 3-dimensional variations in selected positions of artificial teeth in 4 stages of denture fabrication. Analysis of variance (ANOVA) and t tests were performed to compare the groups.Results. A significant difference was found in pin opening between groups (t test). Horizontal dimensional changes evaluated with repeated measures ANOVA revealed no significant differences between groups. However, analysis of vertical dimensional changes disclosed significant differences between the groups. There was no appreciable difference in laboratory working time for flasking and molding denture bases between the injection and compression molding techniques when polymethyl methacrylate resin was used.Conclusion. The injection molding method produced a significantly smaller incisal pin opening over the standard compression molding technique. The injection molding technique, using polymethyl methacrylate, was a more accurate method for processing dentures. There were no appreciable differences in laboratory working time between the injection and compression molding techniques.

Complete staining of nerve fiber and myoneural junctions with acetylthiocholine and silver

We describe a combined stain for simultaneous demonstration of the preterminal axons and cholinesterase activity at myoneural junctions of mammalian muscles. This technique employs acetylthiocholine iodide as the substrate for cholinesterase activity and silver nitrate impregnation of preterminal axons. The procedure is rapid, simple and uses fresh muscles. Intramuscular nerves, preterminal axons and myoneural junctions are stained simultaneously brown or black with minimal background staining of connective tissue and muscle fibers.