Generalized Miura Transformations, Two-Boson KP Hierarchies and their Reduction to KDV Hierarchies

Bracket preserving gauge equivalence is established between several two-boson generated KP type of hierarchies. These KP hierarchies reduce under symplectic reduction (via Dirac constraints) to KdV, mKdV and Schwarzian KdV hierarchies. Under this reduction the gauge equivalence is taking form of the conventional Miura maps between the above KdV type of hierarchies.Comment: 12 pgs., LaTeX, IFT-P/011/93, UICHEP-TH/93-

COVID-19 post-vaccination in healthcare workers and vaccine effectiveness, Brazil, 2021

Objects: This study aimed to describe COVID-19 cases in healthcare workers at a large tertiary hospital, after a vaccination campaign, to understand the individual characteristics, timeliness, symptomatology, and severity of the conditions. Methods: The COVID-19 reporting files from the hospital's healthcare workers and their records in the vaccine registry were analyzed, regarding vaccination status, symptoms, sociodemographic characteristics, comorbidities, and outcomes. Vaccination descriptive analysis was carried out and the impact and effectiveness of vaccination in relation to symptomatic infection and hospitalization were estimated. Results: In a total of 696 PCR-confirmed COVID-19 patients, vaccination coverage for the 1st and 2nd dose was 92.8% and 85.5%. Patients with complete doses had a mean interval of 96.8 days between vaccination and the onset of symptoms. Of the 664 participants with available clinical data, 165 had at least 1 comorbidity. During the study, 12 patients were hospitalized, 58.3% with a complete vaccination schedule. Three of this group died. The effectiveness of vaccination for symptomatic cases and hospitalization was 22.1% and 69.0%, respectively. The impact of vaccination on symptomatic cases and hospitalization was 81.4% and 89.7%, respectively. Discussion: The majority of COVID-19 cases in the study were classified as mild. The impact of vaccination for confirmed cases was significant, both in reducing the incidence of symptomatic cases and hospitalizations. The presence of comorbidities in approximately ¼ of the patients increased the risk of these individuals. The mean time interval between diagnosis and the 2nd dose of vaccine was longer in the hospitalized group, reinforcing the protective decline over longer periods

Enzyme activity as quality indicator of soil under agroforestry systems in the Brazilian Cerrado.

Agroforestry production systems (APS) can be considered a way to produce causing low environmental impact. Besides, APS can be advantageous over conventional agricultural management, since they can offer increased productivity, economic benefits, and more diversity by increasing the possibilities of use a greater number of crops in an economic way. In this presentation, we report the effects of 4 years of two APS installed in the Brazilian Cerrado on soil enzyme activity

Stellar parameters for stars of the CoRoT exoplanet field

Aims:To support the computation and evolutionary interpretation of periods associated with the rotational modulation, oscillations, and variability of stars located in the CoRoT fields, we are conducting a spectroscopic survey for stars located in the fields already observed by the satellite. These observations allow us to compute physical and chemical parameters for our stellar sample. Method: Using spectroscopic observations obtained with UVES/VLT and Hydra/Blanco, and based on standard analysis techniques, we computed physical and chemical parameters ($T_{\rm{eff}}$, $\log \,(g)$, $\rm{[Fe/H]}$, $v_{\rm{mic}}$, $v_{\rm{rad}}$, $v \sin \,(i)$, and $A(\rm{Li})$) for a large sample of CoRoT targets. Results: We provide physical and chemical parameters for a sample comprised of 138 CoRoT targets. Our analysis shows the stars in our sample are located in different evolutionary stages, ranging from the main sequence to the red giant branch, and range in spectral type from F to K. The physical and chemical properties for the stellar sample are in agreement with typical values reported for FGK stars. However, we report three stars presenting abnormal lithium behavior in the CoRoT fields. These parameters allow us to properly characterize the intrinsic properties of the stars in these fields. Our results reveal important differences in the distributions of metallicity, $T_{\rm eff}$, and evolutionary status for stars belonging to different CoRoT fields, in agreement with results obtained independently from ground-based photometric surveys. Conclusions: Our spectroscopic catalog, by providing much-needed spectroscopic information for a large sample of CoRoT targets, will be of key importance for the successful accomplishment of several different programs related to the CoRoT mission, thus it will help further boost the scientific return associated with this space mission.Comment: 43 pages, 17 figures, accepted for publication in A&

The variability behavior of CoRoT M-giant Stars

For 6 years the Convection, Rotation, and Planetary Transits (CoRoT) space mission has acquired photometric data from more than one hundred thousand point sources towards and directly opposite from the inner and outer regions of the Galaxy. The high temporal resolution of the CoRoT data combined with the wide time span of the observations has enabled the study of short and long time variations in unprecedented detail. From the initial sample of 2534 stars classified as M-giants in the CoRoT databasis, we selected 1428 targets that exhibit well defined variability, using visual inspection. The variability period and amplitude of C1 stars (stars having Teff < 4200 K) were computed using Lomb-Scargle and harmonic fit methods. The trends found in the V-I vs J-K color-color diagram are in agreement with standard empirical calibrations for M-giants. The sources located towards the inner regions of the Galaxy are distributed throughout the diagram while the majority of the stars towards the outer regions of the Galaxy are spread between the calibrations of M-giants and the predicted position for Carbon stars. The stars classified as supergiants follow a different sequence from the one found for giant stars. We also performed a KS test of the period and amplitude of stars towards the inner and outer regions of the Galaxy. We obtained a low probability that the two samples come from the same parent distribution. The observed behavior of the period-amplitude and period-Teff diagrams are, in general, in agreement with those found for Kepler sources and ground based photometry, with pulsation being the dominant cause responsible for the observed modulation. We also conclude that short-time variations on M-Giant stars do not exist orare very rare and the few cases we found are possibly related to biases or background stars.Comment: 11 pages, 6 figure

Detecção de enterotoxinas em pools de estirpes de Staphylococcus aureus envolvidas em casos de mastite bovina

De acordo com JARRAUD et al. (1999) e AKINEDEN et al. (2001), as estirpes de S. aureus patogênicos podem produzir enterotoxinas dos tipos A a E e G a J (SEA, SEB, SEC, SED, SEE, SEG, SEH, SEI e SEJ), toxinas esfoliativas dos tipos A e B (ETA, ETB) e toxina da síndrome do choque tóxico (TSST-1), que são responsáveis por causar, em humanos, toxinfecções alimentares, alergias e até mesmo desordens multi-sistêmicas que podem levar à morte. Nos animais, de acordo com FERENS et al. (1998), a patogênese no úbere permanece obscura. No entanto, as toxinas superantigênicas parecem induzir imunossupressão em bovinos leiteiros. O primeiro relato de detecção de TSST-1 produzida por staphylococci de origem animal foi feito por JONES & WIENEKE (1986). Estudos realizados com S. aureus isolados de casos clínicos e subclínicos de mastite bovina demonstraram que entre 20% e 77% dos isolados produziram TSST-1 e enterotoxinas estafilocócicas (KENNY et al., 1993; ICHIKAWA et al., 1996; TAKEUCHI et al., 1998). Em tanques de expansão, utilizados para resfriamento e armazenamento de leite, 75,4% das amostras de S. aureus isoladas demonstraram capacidade de produzir essas toxinas (TAKEUCHI et al., 1998). Diante do exposto, idealizou-se o presente trabalho com a finalidade de verificar a ocorrência de estirpes de S. aureus isoladas de casos de mastite bovina, dos óstios papilares e dos insufladores da ordenhadeira mecânica, capazes de produzir enterotoxinas dos tipos A a D e da toxina da síndrome do choque tóxico (TSST-1)

Gate-bias stress in amorphous oxide semiconductors thin-film transistors

A quantitative study of the dynamics of threshold-voltage shifts with time in gallium-indium zinc oxide amorphous thin-film transistors is presented using standard analysis based on the stretched exponential relaxation. For devices using thermal silicon oxide as gate dielectric, the relaxation time is 3 105 s at room temperature with activation energy of 0.68 eV. These transistors approach the stability of the amorphous silicon transistors. The threshold voltage shift is faster after water vapor exposure suggesting that the origin of this instability is charge trapping at residual-water-related trap sites

Epidemiologia molecular aplicada ao monitoramento de estirpes de Staphylococcus aureus na produção de queijo minas frescal.

Resumo: Foi realizado o monitoramento epidemiológico molecular de estirpes de Staphylococcus aureus potencialmente toxigênicas isoladas no processo de produção do queijo Minas frescal em micro-usina do Estado de São Paulo. Para tanto, foram realizadas seis amostragens durante o período de junho de 2008 a julho de 2009, de modo a perfazer um total de 140 amostras. Essas amostras foram colhidas da superfície dos tanques de recepção e estocagem do leite cru, da superfície do tanque de equilíbrio do leite pasteurizado, da rede de abastecimento de água, das tubulações e equipamentos, das mãos do manipulador e de queijos embalados prontos para consumo. As colônias isoladas em Agar Baird-Parker confirmadas como cocos Gram positivos e que mostravam-se positivas às provas de catalase, coagulase e da produção de acetoína, foram submetidas à extração do DNA bacteriano através da utilização do Kit Invitek - Uniscience®. A confirmação molecular da espécie dos isolados e a presença de enterotoxinas SEA, SEB, SEC, SED e da toxina TSST-1 foi realizada a partir da amplificação dos fragmentos de DNA cromossômico específico. Entre as 74 estirpes de estafilococos coagulase positivos isoladas, somente 41 (55.4%) amostras foram confirmadas como sendo Staphylococcus aureus, das quais 25 (61,0%) mostraram-se positivas na pesquisa de toxinas estafilocócicas. A enterotoxina de maior frequência identificada foi a SEA. As estirpes de Staphylococcus aureus toxigênico foram mais isoladas nas mãos do manipulador (16,0%), no leite cru do tanque de recepção (12,0%), no leite pasteurizado para elaboração do queijo (12,0%) e no queijo Minas frescal pronto para consumo (12,0%). [Molecular epidemiology applied to monitoring strains of staphylococcus Aureus in minas frescal cheese production]. Abstract: We studied the molecular epidemiology of Staphylococcus aureus strains potentially toxigenic, isolated from the production process of Minas frescal cheese in a small dairy plant in the state of São Paulo. For this, samples were taken during the period from June 2008 to July 2009. Samples were collected from the surface of the receiving and storage tanks of raw milk, the surface of the balance tank of pasteurized milk, the water supply system, the pipes and equipments, the hands of the handler and from the packaged cheese, totaling 140 samples. The colonies isolated on Baird-Parker Agar confirmed as Gram positive and positive for catalase, coagulase and acetoin production, were submitted to extraction of bacterial DNA using the Invitek - Uniscience® kit. Confirmation of the isolated species and enterotoxins SEA, SEB, SEC, SED and TSST-1 toxin was carried out through the amplification of specific fragments of chromosomal DNA. Among the 74 strains of isolated coagulase-positive staphylococci, only 41 (55.4%) strains were confirmed as Staphylococcus aureus, of which 25 (61.0%) were positive to the presence of staphylococcal toxins. The most frequently identified enterotoxin was SEA. The toxigenic strains of Staphylococcus aureus were more frequently isolated from hands of the handler (16.0%), raw milk receiving tank (12.0%), pasteurized milk for cheese making (12.0%) and fresh white cheese ready for consumption (12.0%)

Produção de biofilmes por Staphylococcus aureus e a associação com os genes icaAD e clfAB no processo de formação.

A formação de biofilmes nas doenças crônicas de animais pelos Staphylococcus aureus têm aumentado o interesse por pesquisas com a caracterização de genes envolvidos neste processo. Este estudo tem como objetivo determinar a habilidade dos Staphylococcus aureus produzirem biofilmes e associar com os genes de adesão icaAD e clfAB. Foram estudadas 440 estirpes de S. aureus oriundas de leite de vacas com mastite subclínica, tanque de expansão e ambiente de ordenha. Para determinar a produção de biofilme foram realizados os testes fenotípicos do Ágar Vermelho Congo e teste de aderência em microplacas. Para identificar os genes envolvidos foi realizada a reação em cadeia da polimerase. Os resultados demonstraram que a grande maioria dos isolados foram capazes de produzir biofilme ?in vitro? sendo 79% dos isolados de leite e 89% dos isolados de ambiente de ordenha no Agar Vermelho Congo e 84% para as estirpes oriundas de leite e 85% para as estirpes oriundas de ambiente de ordenha no teste de microplacas, sendo que 90%, 97% ,99% e 98% das estirpes apresentaram os genes icaA, icaD, clfB e clfA respectivamente. O envolvimento dos genes com a produção de biofilme principalmente nos equipamentos de ordenhadeira, alerta para um melhor direcionamento nas condutas higiene e sanitazação além da terapia e prevenção da mastite em bovinos leiteiros