Dissipation Scale Fluctuations and Chemical Reaction Rates in Turbulent Flows

Small separation between reactants, not exceeding $10^{-8}-10^{-7}cm$, is the necessary condition for various chemical reactions. It is shown that random advection and stretching by turbulence leads to formation of scalar-enriched sheets of {\it strongly fluctuating thickness} $\eta_{c}$. The molecular-level mixing is achieved by diffusion across these sheets (interfaces) separating the reactants. Since diffusion time scale is $\tau_{d}\propto \eta_{c}^{2}$, the knowledge of probability density $Q(\eta_{c},Re)$ is crucial for evaluation of chemical reaction rates. In this paper we derive the probability density $Q(\eta_{c},Re,Sc)$ and predict a transition in the reaction rate behavior from ${\cal R}\propto \sqrt{Re}$ ($Re\leq 10^{4}$) to the high-Re asymptotics ${\cal R}\propto Re^{0}$. The theory leads to an approximate universality of transitional Reynolds number $Re_{tr}\approx 10^{4}$. It is also shown that if chemical reaction involves short-lived reactants, very strong anomalous fluctuations of the length-scale $\eta_{c}$ may lead to non-negligibly small reaction rates

Scaling transformation and probability distributions for financial time series

The price of financial assets are, since Bachelier, considered to be described by a (discrete or continuous) time sequence of random variables, i.e a stochastic process. Sharp scaling exponents or unifractal behavior of such processes has been reported in several works. In this letter we investigate the question of scaling transformation of price processes by establishing a new connexion between non-linear group theoretical methods and multifractal methods developed in mathematical physics. Using two sets of financial chronological time series, we show that the scaling transformation is a non-linear group action on the moments of the price increments. Its linear part has a spectral decomposition that puts in evidence a multifractal behavior of the price increments.Comment: 10 pages, 4 figures, latex and ps file

Corrección de sesgo en la previsión climática global de la temperatura de la superficie del mar mediante filtros adaptativos en el dominio de la frecuencia

This article applies bias correction to sea surface temperature (SST) predictions using the Recursive Least Squares (RLS) adaptive filter method. We consider the climate predictions of SST produced by the Brazilian Earth System Model (BESM). The SST prediction is corrected using observation proxy data from ERA5 (ECMWF Reanalysis v5). The filters are applied to the prediction time series for the cell or to the frequency coefficients in a region around it obtained by means of the Discrete Cosine Transform in two dimensions (DCT-2D). Filters of different orders and different size for the region are tested. The correction methodology is tested for the one-year horizon or the seasons separately. The performance of the correction of the BESM SST prediction is evaluated using the Root Mean Squared Error and the Mean Absolute Error, comparing the proposed approach with adaptive RLS filtering in the time domain and the CMV (mean and variance adjustments) in both time and frequency domains, considering adjustments on annual and seasonal scales. In general, it was found that the proposed method presents a correction capability equivalent to that of the RLS and CMV methods in the time domain, while the adjustment via CMV in the frequency domain does not offer good results.Este artículo aplica la corrección de sesgo en las predicciones de la temperatura de la superficie del mar (TSM) utilizando el método de filtros adaptativos RLS (Recursive Least Squares). Las predicciones climáticas de TSM son producidas por el Modelo Brasileño del Sistema Terrestre (BESM). La predicción de TSM se corrige utilizando como referencia un proxy de observación, los datos del ERA5 (ECMWF Reanalysis v5). Los filtros se aplican a las series de predicciones para cada celda o en los coeficientes frecuenciales obtenidos a través de la Transformada de Coseno Discreta bidimensional (DCT-2D) en una región alrededor de la celda. Se prueban filtros de diferentes órdenes y se consideran regiones de diferentes tamaños. La metodología de corrección se prueba considerando la serie anual y estaciones del año, por separado. Se evalúa el rendimiento de la corrección de la predicción de TSM prevista por BESM utilizando la Raíz del Error Cuadrático Medio y el Error Absoluto Medio, comparando el enfoque propuesto con el uso de filtrado adaptativo RLS en el dominio del tiempo y los ajustes de media y varianza (CMV) en los dominios del tiempo y la frecuencia, teniendo en cuenta los ajustes en las escalas anual y estacional. En general, se encontró que el método propuesto presenta una capacidad de corrección equivalente a la del método RLS y CMV en el dominio del tiempo, mientras que el ajuste mediante CMV en el dominio de la frecuencia no ofrece buenos resultados.Este artigo aplica a correção de viés nas previsões de temperatura da superfície do mar (TSM) usando filtros adaptativos RLS (Recursive Least Squares). Consideram-se as previsões climáticas de TSM produzidas pelo Modelo Brasileiro do Sistema Terrestre (BESM). A previsão da TSM é corrigida usando como referência, proxy de observação, os dados do ERA5 (ECMWF Reanalysis v5). Os filtros são aplicados nas séries temporais das previsões para uma célula da grade ou em coeficientes frequenciais obtidos via Transformada Cosseno Discreta bidimensional (DCT-2D) em uma região em torno da célula. São testados filtros de diferentes ordens e são consideradas regiões de diferentes tamanhos. A metodologia de correção é testada para o horizonte de 1 ano e ainda considera-se a correção por estações do ano, separadamente. Avalia-se o desempenho da correção da previsão da usando a Raiz do Erro Quadrático Médio e o Erro Absoluto Médio, comparando-se a abordagem proposta com as da filtragem adaptativa RLS no domínio do tempo e os ajustes de média e variância (CMV) nos domínios do tempo e na frequência, tendo em vista os ajustes nas escalas anual e sazonal. De modo geral, verificou-se que o método proposto apresenta uma capacidade de correção equivalente ao do método RLS e CMV no domínio do tempo, enquanto o ajuste via CMV no domínio da frequência não oferece bons resultados

The inactivated NDV-HXP-S COVID-19 vaccine induces a significantly higher ratio of neutralizing to non-neutralizing antibodies in humans as compared to mRNA vaccines

NDV-HXP-S is a recombinant Newcastle disease virus based-vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which expresses an optimized (HexaPro) spike protein on its surface. The vaccine can be produced in embryonated chicken eggs using the same process as that employed for the production of influenza virus vaccines. Here we performed a secondary analysis of the antibody responses after vaccination with inactivated NDV-HXP-S in a Phase I clinical study in Thailand. Please click Download on the upper right corner to see the full abstract

Induction of hemagglutinin stalk reactive antibodies by the administration of a live-attenuated influenza virus vaccine in children

Early life exposures to influenza viruses may imprint a hemagglutinin group-specific signature on immunity that impacts future responses to infection or vaccination. We assessed the administration of a live attenuated influenza virus (LAIV) vaccine in children. Two LAIV formulations (2016–17 and 2017–18) containing distinct H1N1 components were used. Modest boosting of pre-existing serum stalk reactive titers and enhancement of functional antibody-dependent cellular cytotoxicity activity (ADCC) was observed. The magnitude of stalk antibody induction in children naive to influenza A viruses was low; however, LAIV induced de novo stalk antibodies, increasing the number of children seropositive to both group 1 (G1) and group 2 (G2) influenza viruses. The 2018 LAIV formulation, containing an updated H1N1 component, induced higher stalk reactive antibodies with strong ADCC effector functions to the G1 stalk. No significant changes were detected in NA-reactive antibodies in serum or in stalk- or NA-secretory IgA (sIgA) in oral fluid

Induction of hemagglutinin stalk reactive antibodies by the administration of a live-attenuated influenza virus vaccine in children

Early life exposures to influenza viruses may imprint a hemagglutinin group-specific signature on immunity that impacts future responses to infection or vaccination. We assessed the administration of a live attenuated influenza virus (LAIV) vaccine in children. Two LAIV formulations (2016–17 and 2017–18) containing distinct H1N1 components were used. Modest boosting of pre-existing serum stalk reactive titers and enhancement of functional antibody-dependent cellular cytotoxicity activity (ADCC) was observed. The magnitude of stalk antibody induction in children naive to influenza A viruses was low; however, LAIV induced de novo stalk antibodies, increasing the number of children seropositive to both group 1 (G1) and group 2 (G2) influenza viruses. The 2018 LAIV formulation, containing an updated H1N1 component, induced higher stalk reactive antibodies with strong ADCC effector functions to the G1 stalk. No significant changes were detected in NA-reactive antibodies in serum or in stalk- or NA-secretory IgA (sIgA) in oral fluid

Formação do biofilme em canais radiculares medicados

Os microrganismos são os principais agentes etiológicos das alterações pulpares e periapicais. Uma vez que as células de defesa do hospedeiro não alcançam o interior dos canais radiculares, é necessário que os microrganismos sejam eliminados durante o tratamento endodôntico através do preparo químico e mecânico e medicação intracanal. Este estudo teve como objetivo testar a hipótese de que o Enterococcus faecalis é capaz de formar biofílme em canais radiculares que apresentam diferentes medicações intracanais. Para tanto, quarenta raízes de incisivos inferiores humanos com comprimento padronizado em 15 mm foram instrumentados e divididos em 6 grupos de acordo com a medicação intracanal testada (Clorexidina gel 2%, Ca(OH)2 + Clorexidina gel 2% (1:1), Ca{OH)2 + água destilada, sem medicação intracanal - grupo controle positivo, natrosol gel - grupo controle positivo e sem medicação intracanal e sem inoculação bacteriana - grupo controle negativo).Eppendorfs com as pontas cortadas foram inseridos em pequenos frascos de vidro contendo BHI caldo associado a neutralizadores da ação antimicrobiana específicos à cada medicação utilizada. Cada raiz, previamente instrumentada, foi posicionada no interior de cada conjunto frasco de vidro-eppendorf. Na interface dente-tampa, aplicou-se adesivo epóxi e cianoacrílato a fim de impedir uma contaminação bacteriana via interface no meio de cultura (Imura et. al., 1997).O aparato foi incubado a 37°C em câmara de C02. A turbidez do meio de cultura foi verificada diariamente. Os dias necessários para o crescimento bacteriano no BHI foram considerados como o tempo requerido para a contaminação das medicações intracanais testadas. A confirmação desta contaminação foi feita através do crescimento bacteriano em BHI agar, teste de catalase e Gram

Non-linear dynamics of mooring lines

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Ocean Engineering, 1997.Includes bibliographical references (p. 89).by Genevieve Tcheou.M.S

Flow boiling of refrigerant-oil mixtures in horizontal, plain and microfin tubes

SIGLEAvailable from British Library Document Supply Centre-DSC:DXN021562 / BLDSC - British Library Document Supply CentreGBUnited Kingdo