1,457 research outputs found

    Lagrangian formulation for noncommutative nonlinear systems

    Full text link
    In this work we use the well known formalism developed by Faddeev and Jackiw to introduce noncommutativity within two nonlinear systems, the SU(2) Skyrme and O(3) nonlinear sigma models. The final result is the Lagrangian formulations for the noncommutative versions of both models. The possibility of obtaining different noncommutative versions for these nonlinear systems is demonstrated.Comment: 8 pages. Revex 4.

    Polyoxometalates as promoters of laccase-assisted reactions

    Get PDF
    A synergistic effect of polyoxometalate and laccase benzenediol:oxygen oxidoreductase, EC 1.10.3.2 has been observed in the aerobic oxidation of a hydrazonaphthalene type colorant. The considerable increase in the decolorization rate of Solophenyl Blue GL dye with the new catalytic system composed by laccase and heptamolybdopentovanadophosphate heteropolyanion, when compared with the treatment with enzyme or heteropolyanion alone, was tentatively explained by the redox mediation action of the heteropolyanion

    Associations between changes in oxygenation, dead space and driving pressure induced by the first prone position session and mortality in patients with acute respiratory distress syndrome

    Get PDF
    Background: Outcome prediction in acute respiratory distress syndrome (ARDS) is challenging, especially in patients with severe hypoxemia. The aim of the current study was to determine the prognostic capacity of changes in PaO2/FiO2, dead space fraction (VD/VT) and respiratory system driving pressure (\u394PRS) induced by the first prone position (PP) session in patients with ARDS. Methods: This was a post hoc analysis of the conveniently-sized 'Molecular Diagnosis and Risk Stratification of Sepsis' study (MARS). The current analysis included ARDS patients who were placed in the PP. The primary endpoint was the prognostic capacity of the PP-induced changes in PaO2/FiO2, VD/VT, and \u394PRS for 28-day mortality. PaO2/FiO2, VD/VT, and \u394PRS was calculated using variables obtained in the supine position before and after completion of the first PP session. Receiving operator characteristic curves (ROC) were constructed, and sensitivity, specificity positive and negative predictive value were calculated based on the best cutoffs. Results: Ninety patients were included; 28-day mortality was 46%. PP-induced changes in PaO2/FiO2 and VD/VT were similar between survivors vs. non-survivors [+83 (+24 to +137) vs. +58 (+21 to +113) mmHg, and -0.06 (-0.17 to +0.05) vs. -0.08 (-0.16 to +0.08), respectively]. PP-induced changes in \u394PRS were different between survivors vs. non-survivors [-3 (-7 to 2) vs. 0 (-3 to +3) cmH2O; P=0.03]. The area under the ROC of PP-induced changes in \u394PRS for mortality, however, was low [0.63 (95% confidence interval (CI), 0.50 to 0.75]; PP-induced changes in \u394PRS had a sensitivity and specificity of 76% and 56%, and a positive and negative predictive value of 60% and 73%. Conclusions: Changes in PaO2/FiO2, VD/VT, and \u394PRS induced by the first PP session have poor prognostic capacities for 28-day mortality in ARDS patients

    Squamous cell carcinoma of the lip: assessment of prognostic factors

    Get PDF
    Among lip cancers, 90% to 95% of them affect the lower lip and squamous cell carcinoma is the most frequent type. The TNM classification synthesizes the clinical characteristics of the tumor that allows prognosis and makes possible the comparisons of the results. Three parameters have to be considered: size of the tumor (T), propagation to regional lymphatic ganglion (N) and metastasis (M); however, patterns starting from 2cm are established by the TNM classification. In the case of squamous cell carcinoma of the lips, 2cm lesions are considered extremely large. AIM: The objective of this study was to verify the correlation among epidemiologic, clinical, evolutionary and histopathological characteristics of squamous cell carcinoma of the lips, having as parameter lesions as small as 0.5cm. MATERIAL AND METHODS: In the period 1993-2000 in São Paulo, Brazil, a transversal retrospective study was performed with patients exhibiting squamous cell carcinoma of the lips. The characteristics of the tumor were investigated through the analysis of patients' medical charts, original reports of the histopathological exams and tumors' samples. The tumors were classified from 0.5 to 2.5cm. In addition, type, grade of histologic differentiation, the presence of desmoplasia, muscular, neural and vascular infiltration, and type of inflammatory infiltrate were investigated. RESULTS: The statistical analyses indicated that metastasis and recurrences do not depend on patients' gender and race. The independence of the tumor's localization, either in the upper or lower lip, and the incidence of metastasis and recurrence were demonstrated. A correlation between lesions as large as 0.5cm and the occurrence of metastasis and recurrence was verified. Furthermore, it was observed that the size of lesion determines the infiltration in other tissues. Lymphoplasmocytarian is the type of inflammatory infiltrate that was found in each and every lesion. On the other hand, in some of the lesions, the inflammatory infiltrate was associated with eosinophils without correlation to size of tumor. CONCLUSION: Smaller tumors than 2cm, from a histopathological and clinical point of view, may present a distinct evolution behavior. Most of the lesions are ulcerative, though the ulcerative-vegetative is the one that presents the most metastasis and recurrence. The ulcerative-vegetative and vegetative types are associated with the largest lesions. The size of the tumor is related, in a similar way, to grades II and III, in which higher rates of metastasis and recurrence were observed. In decreasing order of frequency, the tumor invades muscles, nerves and blood vessels, which can be related to the size of the lesion. Thus, in order to have metastasis, it is necessary to have infiltration of muscles. Yet, blood vessels can only be involved when there is concomitant infiltration of nerves. As a result, desmoplasia is directly related to size of the lesion as well as to occurrence of metastasis.Dentre os cânceres do lábio de 90% a 95% dos casos afetam o lábio inferior, sendo o carcinoma espinocelular o mais freqüente. A classificação TNM sintetiza as características clínicas do tumor, permitindo realizar um prognóstico e possibilitando comparações dos resultados. Relaciona três parâmetros: tamanho do tumor (T), propagação aos gânglios linfáticos regionais (N) e metástases à distância (M), mas estabelece padrões a partir de 2cm. Para o carcinoma espinocelular do lábio lesões com 2cm são extremamente grandes. OBJETIVO: O objetivo deste estudo é verificar a relação entre as características epidemiológicas, clínicas, evolutivas e histopatológicas do carcinoma espinocelular do lábio tendo como parâmetro lesões de tamanhos a partir de 0,5cm. CASUÍSTICA E MÉTODO: Foi elaborado um estudo retrospectivo transversal em pacientes com carcinoma espinocelular do lábio, no período 1993-2000, em São Paulo, Brasil. Estudou-se prontuários, laudos originais dos exames histopatológicos e lâminas de tumores de pacientes com carcinoma espinocelular do lábio. Os tumores foram classificados de 0.5 em 0.5cm, sendo verificado o tipo, o grau de diferenciação histológica, a presença de desmoplasia, as invasões muscular, neural e vascular, e o tipo de infiltrado inflamatório. RESULTADOS: A análise estatística mostrou que metástases e recidivas não dependem da cor de pele ou do sexo dos pacientes e que há independência entre a localização do tumor, no lábio superior ou inferior, e a incidência de metástases e recidiva. Houve correlação entre o tamanho da lesão a partir de 0,5cm e a ocorrência de metástases e recidiva. Verificou-se que o tamanho da lesão determina a invasão em outros tecidos. O infiltrado inflamatório verificado em todas as lesões era linfoplasmocitário e, em algumas, associado com eosinófilos sem relação com o tamanho do tumor. CONCLUSÃO: Tumores menores que 2cm podem apresentar comportamentos evolutivos distintos, sob o ponto de vista clínico e histopatológico. O tipo mais prevalente de lesão é o ulcerativo e o que mais metastatiza e recidiva é o úlcero-vegetante. Os tipos úlcero-vegetante e vegetante estão ligados a lesões de maior tamanho. O tamanho do tumor se relaciona, de forma semelhante, com os graus II e III, nos quais ocorrem os maiores índices de metástases e recidivas. O tumor invade em ordem decrescente de freqüência músculos, nervos e vasos sanguíneos, e esta pode ser prevista pelo tamanho da lesão. É necessária a invasão dos músculos para a ocorrência de metástases, sendo que os vasos sanguíneos somente podem estar implicados quando há invasão concomitante dos nervos. A desmoplasia está diretamente relacionada ao tamanho da lesão e à ocorrência de metástases.UNIFESP-EPMUNIFESP-EPM setor de EstomalogiaUNIFESP-EPM Departamento de DermatologiaUNIFESP, EPM, setor de EstomalogiaUNIFESP, EPM Depto. de DermatologiaSciEL

    Noncommutative cosmological models coupled to a perfect fluid and a cosmological constant

    Full text link
    In this work we carry out a noncommutative analysis of several Friedmann-Robert-Walker models, coupled to different types of perfect fluids and in the presence of a cosmological constant. The classical field equations are modified, by the introduction of a shift operator, in order to introduce noncommutativity in these models. We notice that the noncommutative versions of these models show several relevant differences with respect to the correspondent commutative ones.Comment: 27 pages. 7 figures. JHEP style.arXiv admin note: substantial text overlap with arXiv:1104.481

    Dual embedding of the Lorentz-violating electrodinamics and Batalin-Vilkovisky quantization

    Full text link
    Modifications of the electromagnetic Maxwell Lagrangian in four dimensions have been considered by some authors. One may include an explicit massive term (Proca) and a topological but not Lorentz-invariant term within certain observational limits. We find the dual-corresponding gauge invariant version of this theory by using the recently suggested gauge embedding method. We enforce this dualisation procedure by showing that, in many cases, this is actually a constructive method to find a sort of parent action, which manifestly establishes duality. We also use the gauge invariant version of this theory to formulate a Batalin-Vilkovisky quantization and present a detailed discussion on the excitation spectrum.Comment: 8 page

    Fontes de resistência a Magnaporthe oryzae com potencial de uso no melhoramento de arroz (Oryza sativa).

    Get PDF
    Este trabalho teve o objetivo de identificar e selecionar potenciais doadores de genes de resistência a Magnaporthe oryzae úteis aos programas de melhoramento de arroz no Brasil

    Dirac-like Monopoles in Three Dimensions and Their Possible Influences on the Dynamics of Particles

    Get PDF
    Dirac-like monopoles are studied in three-dimensional Abelian Maxwell and Maxwell-Chern-Simons models. Their scalar nature is highlighted and discussed through a dimensional reduction of four-dimensional electrodynamics with electric and magnetic sources. Some general properties and similarities of them when are considered in Minkowski or Euclidian space are mentioned. However, by virtue of the structure of the space-time in which they are considered a number of differences among them take place. Furthermore, we pay attention to some consequences of these objects when acting upon usual particles. Among other subjects, special attention is given to the study of a Lorentz-violating non-minimal coupling between neutral fermions and the field generated by a monopole alone. In addition, an analogue of the Aharonov-Casher effect is discussed in this framework.Comment: 20 pages. Latex format. No figures. Accepted for publication in Phys. Rev.
    corecore