953 resultados para Conditional Cramer-Rao bound
Resumo:
O presente trabalho teve por objetivo determinar o efeito de genótipos de maracujazeiro quanto à atratividade e à não-preferência para alimentação de lagartas de Dione juno juno, em diferentes idades, através de testes com e sem chance de escolha. Os experimentos foram conduzidos no Departamento de Fitossanidade da FCAV/UNESP de Jaboticabal-SP, sob condições ambientais controladas (T=26=±=1°C=U.=R.= 60 ± 10% e fotofase = 14 horas), utilizando-se dos genótipos Passiflora edulis, P. gibertii, P. alata, Sul Brasil, IAC-275, Flora FB 300, P. serrato-digitata, P. edulis f. flavicarpa, Maguary FB-100 e P. foetida. Para o teste com chance de escolha, foram utilizadas placas de Petri, onde foram distribuídos, de forma eqüidistante, um disco foliar (3,2 cm) de cada genótipo estudado e liberando-se em seguida, no centro da placa, 5 lagartas recém-eclodidas ou uma lagarta com 10 dias de idade por material. No teste sem chance de escolha, foi colocado apenas um disco de cada genótipo por placa de Petri (9 cm de diâmetro), mantendo-se o mesmo padrão de infestação utilizado no teste com chance. As avaliações foram realizadas em duas etapas, sendo que, na primeira, avaliou-se a atratividade, contando o número de lagartas em cada material a 1; 3; 5; 10; 15; 30; 60; 120; 240 minutos e 24 horas após a liberação das mesmas. Na segunda etapa, observou-se o consumo foliar 24 horas após o início do teste. O genótipo menos atrativo às lagartas recém-eclodidas e de 10 dias de idade foi P. alata em testes com e sem chance de escolha. O genótipo P. alata foi o menos consumido em teste com chance de escolha, sendo que, no teste sem chance, P. alata e P. foetida destacaram-se como os menos consumidos para as duas fases larvais.
Resumo:
Avaliou-se o efeito de genótipos de maracujazeiro no desenvolvimento de Dione juno juno (Cramer) (Lepidoptera: Nymphalidae). O experimento foi conduzido em laboratório, sob condições ambientais controladas (temperatura de 26 ± 1ºC, U. R. de 60 ± 10% e fotofase de 14 horas). Lagartas recém-eclodidas foram alimentadas com folhas de genótipos de maracujazeiro: Passiflora edulis Sims., P. alata Dryand., P. serrato-digitata L., P. edulis f. flavicarpa Deg. ('Sul Brasil'), P. edulis f. flavicarpa, P. edulis f. flavicarpa ('Maguary FB-100') e P. foetida L. Para cada genótipo estudado, utilizaram-se 50 lagartas, provenientes de ovos coletados no campo. Essas lagartas foram mantidas em ramos de maracijazeiro, no interior de tubos de PVC até a pupação. Observações e reposição do alimento (ramos), diárias, foram realizadas. Os parâmetros avaliados foram duração e viabilidade das fases larval e pupal, peso das lagartas, peso das pupas e longevidade do adulto. O delineamento experimental foi o de blocos casualizados, com sete tratamentos e dez repetições. Os dados obtidos foram submetidos à análise de variância, e quando observadas diferenças, as médias foram comparadas pelo teste de Tukey, a 5% de probabilidade. Os genótipos P. alata, P. serrato-digitata e P. foetida não são adequados ao desenvolvimento de D. juno juno, impossibilitando a sobrevivência das lagartas, o que mostra o alto grau de antibiose desses materiais. Entre os demais, P. edulis, P. edulis f. flavicarpa, Maguary FB-100 e Sul Brasil foram mais adequados.
Resumo:
The concept of conditional stability constant is extended to the competitive binding of small molecules to heterogeneous surfaces or macromolecules via the introduction of the conditional affinity spectrum (CAS). The CAS describes the distribution of effective binding energies experienced by one complexing agent at a fixed concentration of the rest. We show that, when the multicomponent system can be described in terms of an underlying affinity spectrum [integral equation (IE) approach], the system can always be characterized by means of a CAS. The thermodynamic properties of the CAS and its dependence on the concentration of the rest of components are discussed. In the context of metal/proton competition, analytical expressions for the mean (conditional average affinity) and the variance (conditional heterogeneity) of the CAS as functions of pH are reported and their physical interpretation discussed. Furthermore, we show that the dependence of the CAS variance on pH allows for the analytical determination of the correlation coefficient between the binding energies of the metal and the proton. Nonideal competitive adsorption isotherm and Frumkin isotherms are used to illustrate the results of this work. Finally, the possibility of using CAS when the IE approach does not apply (for instance, when multidentate binding is present) is explored. © 2006 American Institute of Physics.
Resumo:
A biologia de Spodoptera eridania foi estudada em laboratório (22±1ºC, UR 70±10%, fotofase de 14 horas), em folhas de morangueiro (Fragaria x ananassa cv. 'Aromas') e videira (Vitis vinifera cv. 'Cabernet Sauvignon'). A duração e a viabilidade do ciclo total foram, respectivamente, de 52,2±1,32 dias e 37,6% para morangueiro e 42,2±0,45 dias e 25,5% para videira. A razão sexual em morangueiro foi de 0,58, e 0,48 em videira. A longevidade média de machos e fêmeas em morangueiro foi de 16,3±1,16 e 15,8±1,85 dias, respectivamente, e 5,6±0,88 e 7,3±0,83 dias em videira. A fecundidade média total foi de 1.747,5±187,32 ovos por fêmea em morangueiro, e 1.764,9±289,04 em videira. A tabela de vida de fertilidade mostrou que a taxa líquida de reprodução e a razão finita de aumento foram de 394,89 e 1,10, respectivamente, para morangueiro, e de 213,98 e 1,12 para videira. As culturas do morangueiro cv. 'Aromas' e da videira cv. 'Cabernet Sauvignon' são hospedeiras favoráveis e equivalentes quanto ao potencial de crescimento populacional de S. eridania.
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Heterozygous germline mutations in the zinc finger transcription factor GATA2 have recently been shown to underlie a range of clinical phenotypes, including Emberger syndrome, a disorder characterized by lymphedema and predisposition to myelodysplastic syndrome/acute myeloid leukemia (MDS/AML). Despite well-defined roles in hematopoiesis, the functions of GATA2 in the lymphatic vasculature and the mechanisms by which GATA2 mutations result in lymphedema have not been characterized. Here, we have provided a molecular explanation for lymphedema predisposition in a subset of patients with germline GATA2 mutations. Specifically, we demonstrated that Emberger-associated GATA2 missense mutations result in complete loss of GATA2 function, with respect to the capacity to regulate the transcription of genes that are important for lymphatic vessel valve development. We identified a putative enhancer element upstream of the key lymphatic transcriptional regulator PROX1 that is bound by GATA2, and the transcription factors FOXC2 and NFATC1. Emberger GATA2 missense mutants had a profoundly reduced capacity to bind this element. Conditional Gata2 deletion in mice revealed that GATA2 is required for both development and maintenance of lymphovenous and lymphatic vessel valves. Together, our data unveil essential roles for GATA2 in the lymphatic vasculature and explain why a select catalogue of human GATA2 mutations results in lymphedema.
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The membrane-bound serine protease CAP2/Tmprss4 has been previously identified in vitro as a positive regulator of the epithelial sodium channel (ENaC). To study its in vivo implication in ENaC-mediated sodium absorption, we generated a knockout mouse model for CAP2/Tmprss4. Mice deficient in CAP2/Tmprss4 were viable, fertile, and did not show any obvious histological abnormalities. Unexpectedly, when challenged with sodium-deficient diet, these mice did not develop any impairment in renal sodium handling as evidenced by normal plasma and urinary sodium and potassium electrolytes, as well as normal aldosterone levels. Despite minor alterations in ENaC mRNA expression, we found no evidence for altered proteolytic cleavage of ENaC subunits. In consequence, ENaC activity, as monitored by the amiloride-sensitive rectal potential difference (ΔPD), was not altered even under dietary sodium restriction. In summary, ENaC-mediated sodium balance is not affected by lack of CAP2/Tmprss4 expression and thus, does not seem to directly control ENaC expression and activity in vivo.
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Replication of human immunodeficiency virus (HIV) requires base pairing of the reverse transcriptase primer, human tRNA(Lys3), to the viral RNA. Although the major complementary base pairing occurs between the HIV primer binding sequence (PBS) and the tRNA's 3'-terminus, an important discriminatory, secondary contact occurs between the viral A-rich Loop I, 5'-adjacent to the PBS, and the modified, U-rich anticodon domain of tRNA(Lys3). The importance of individual and combined anticodon modifications to the tRNA/HIV-1 Loop I RNA's interaction was determined. The thermal stabilities of variously modified tRNA anticodon region sequences bound to the Loop I of viral sub(sero)types G and B were analyzed and the structure of one duplex containing two modified nucleosides was determined using NMR spectroscopy and restrained molecular dynamics. The modifications 2-thiouridine, s(2)U(34), and pseudouridine, Psi(39), appreciably stabilized the interaction of the anticodon region with the viral subtype G and B RNAs. The structure of the duplex results in two coaxially stacked A-form RNA stems separated by two mismatched base pairs, U(162)*Psi(39) and G(163)*A(38), that maintained a reasonable A-form helix diameter. The tRNA's s(2)U(34) stabilized the interaction between the A-rich HIV Loop I sequence and the U-rich anticodon, whereas the tRNA's Psi(39) stabilized the adjacent mismatched pairs.
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By theorems of Ferguson and Lacey ($d=2$) and Lacey and Terwilleger ($d>2$), Nehari's theorem is known to hold on the polydisc $\D^d$ for $d>1$, i.e., if $H_\psi$ is a bounded Hankel form on $H^2(\D^d)$ with analytic symbol $\psi$, then there is a function $\varphi$ in $L^\infty(\T^d)$ such that $\psi$ is the Riesz projection of $\varphi$. A method proposed in Helson's last paper is used to show that the constant $C_d$ in the estimate $\|\varphi\|_\infty\le C_d \|H_\psi\|$ grows at least exponentially with $d$; it follows that there is no analogue of Nehari's theorem on the infinite-dimensional polydisc.
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Improving educational quality is an important public policy goal. However, its success requires identifying factors associated with student achievement. At the core of these proposals lies the principle that increased public school quality can make school system more efficient, resulting in correspondingly stronger performance by students. Nevertheless, the public educational system is not devoid of competition which arises, among other factors, through the efficiency of management and the geographical location of schools. Moreover, families in Spain appear to choose a school on the grounds of location. In this environment, the objective of this paper is to analyze whether geographical space has an impact on the relationship between the level of technical quality of public schools (measured by the efficiency score) and the school demand index. To do this, an empirical application is performed on a sample of 1,695 public schools in the region of Catalonia (Spain). This application shows the effects of spatial autocorrelation on the estimation of the parameters and how these problems are addressed through spatial econometrics models. The results confirm that space has a moderating effect on the relationship between efficiency and school demand, although only in urban municipalities.
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This study investigates the relationship between the time-varying risk premiums and conditional market risk in the stock markets of the ten member countries of Economy and Monetary Union. Second, it examines whether the conditional second moments change over time and are there asymmetric effects in the conditional covariance matrix. Third, it analyzes the possible effects of the chosen testing framework. Empirical analysis is conducted using asymmetric univariate and multivariate GARCH-in-mean models and assuming three different degrees of market integration. For a daily sample period from 1999 to 2007, the study shows that the time-varying market risk alone is not enough to explain the dynamics of risk premiums and indications are found that the market risk is detected only when its price is allowed to change over time. Also asymmetric effects in the conditional covariance matrix, which is found to be time-varying, are clearly present and should be recognized in empirical asset pricing analyses.
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A chromatographic method was developed for cholesterol determination in feed for ruminants using response surface methodology. Among the five approaches of sample preparation methods tested, the saponification of the sample without heating presented less interference in the gas chromatography. The method presented a relative standard deviation (RSD) of 4.3%, recoveries between 84 and 87% and detection limit of 0.001 mg of cholesterol per g of feed.
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Our previous paper showed fragmentary evidence that pulp brightness reversion may be negatively affected by its organically bound chlorine (OX) content. A thorough investigation on eucalyptus kraft pulp led to the conclusion that OX increases reversion of certain pulps but this trend is not universal. Alkaline bleaching stages decrease reversion regardless of pulp OX content. Pulps bleached with high temperature chlorine dioxide revert less than those bleached with conventional chlorine dioxide in sequences ending with a chlorine dioxide stage but similarly in sequences ending with a final peroxide stage. The use of secondary condensate for pulp washing decreases reversion.
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In this research, we seek to corroborate the contributions of Chemistry to the identification, extraction and classification of minerals in the XVIII century, as well as, to approach the discussion that History of Chemistry shouldn't be understood in terms of a tight line of thoughts. For that, we analyze the work of Johann Andreas Cramer (1710-1777), Elements of the Art of Assaying Metals. Cramer proposed a method of mineral assaying based on the chemical behavior of the bodies, which allowed him to identify, extract and classify the minerals with more assertiveness.