1,111 research outputs found

    Did Germinal Centers evolve under differential effects of diversity vs affinity?

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    The classical view on the process of mutation and affinity maturation that occurs in GCs assumes that their major role is to generate high affinity levels of serum Abs, as well as a dominant pool of high affinity memory B cells, through a very efficient selection process. Here we present a model that considers different types of structures where a mutation selection process occurs, with the aim at discussing the evolution of Germinal Center reactions. Based on the results of this model, we suggest that in addition to affinity maturation, the diversity generated during the GC reaction may have also been important in the evolution towards the presently observed highly organized structure of GC in higher vertebrates

    The Complex Physics of Dusty Star-forming Galaxies at High Redshifts as Revealed by Herschel and Spitzer

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    We combine far-infrared photometry from Herschel (PEP/HerMES) with deep mid-infrared spectroscopy from Spitzer to investigate the nature and the mass assembly history of a sample of 31 luminous and ultraluminous infrared galaxies ((U)LIRGs) at z ~ 1 and 2 selected in GOODS-S with 24 μm fluxes between 0.2 and 0.5 mJy. We model the data with a self-consistent physical model (GRASIL) which includes a state-of-the-art treatment of dust extinction and reprocessing. We find that all of our galaxies appear to require massive populations of old (>1 Gyr) stars and, at the same time, to host a moderate ongoing activity of star formation (SFR ≤ 100 M_☉ yr^(–1)). The bulk of the stars appear to have been formed a few Gyr before the observation in essentially all cases. Only five galaxies of the sample require a recent starburst superimposed on a quiescent star formation history. We also find discrepancies between our results and those based on optical-only spectral energy distribution (SED) fitting for the same objects; by fitting their observed SEDs with our physical model we find higher extinctions (by ΔA_V ~ 0.81 and 1.14) and higher stellar masses (by Δlog(M_★) ~ 0.16 and 0.36 dex) for z ~ 1 and z ~ 2 (U)LIRGs, respectively. The stellar mass difference is larger for the most dust-obscured objects. We also find lower SFRs than those computed from L IR using the Kennicutt relation due to the significant contribution to the dust heating by intermediate-age stellar populations through "cirrus" emission (~73% and ~66% of the total L IR for z ~ 1 and z ~ 2 (U)LIRGs, respectively)

    Specificity and kinetics of the milk-clotting enzyme from cardoon (Cynara cardunculus L.) toward bovine .kappa.-casein

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    The action of Cynara cardunculus L. protease on whole bovine K-casein, over a 3-h period at pH 6.4, was investigated. RpHPLC of the 3% trichloroacetic acid (TCA)-solublefraction of the K-casein digestion mixture showed three peptide peaks, which were identified by amino acid analysis and N-terminal analysis as the 106-169 fragment [caseinomacropeptide (CMP)]. Upon selective precipitation with 12% TCA, one glycosylated and two nonglycosylated forms of CMP were distinguished. Analysis of the whole digestion mixture showed no additional peptides. The kinetics of hydrolysis of the PhelO5- Met106 bond was studied by spectrofluorometry, using fluorescein isothiocyanate-labeled K-casein (FTC- K-casein). The values obtained for kat, k, and k were 1.04 s-l, 0.16 pM, and 6.5 pM-l s-l, respectively. The proteolytic coefficient is of the same order of magnitude as those obtained for other milk-clotting enzymes, but the k, is significantly lower, which reflects the higher affinity of Cynara protease to K-casei

    Jornalismo e crítica da cultura: a urgência da nova identidade

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    The article discusses the various conceptual issues involving Cultural journalism as a result of the proliferation of virtual spaces of criticism. As a consequence, the system of credibility with which the genus has built its presence in the public sphere seems to be called into question both within the professional activity and in public references. The dilemma, which leverages the difficulties faced by genre historically, suggests a review of theoretical assumptions on which the journalistic practice of critique of culture sits.Key words: cultural journalism, digital technologies, public sphere.O artigo discute as diversas questões conceituais que envolvem o Jornalismo Cultural em consequência da proliferação de espaços virtuais de crítica. Como resultado, o sistema de credibilidade com o qual o gênero construiu sua presença na esfera pública parece estar sendo posto em xeque tanto no interior da atividade profissional quanto nas referências do público. O dilema, que potencializa dificuldades que o gênero enfrenta historicamente, sugere uma revisão de pressupostos teóricos nos quais a prática jornalística da crítica da cultura se assenta.Palavras-chave: jornalismo cultural, tecnologias digitais, esfera pública

    Pott’s Puffy Tumor Caso Clínico

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    RESUMO A osteomielite do osso frontal, também conhecida como tumor de Pott, é uma complicação rara da sinusite frontal. Manifesta-se mais vezes na adolescência e geralmente quando há envolvimento intracraniano, em particular por um quadro meníngeo, que pode ter uma evolução insidiosa. Relata-se o caso de um adolescente de 12 anos com uma apresentação atípica

    Indústrias midiáticas brasileiras: um projeto de História * Doutor em Jornalismo pela ECA/USP, professor do curso de pós-graduação e coordenador dos cursos de graduação da Centro

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    No conjunto da reconstituição dos processos culturais, elemento essencial paraa compreensão das transformações do final do século, a História da IndústriaMidiática no Brasil recupera o papel dos meios de comunicação comoinstrumento de intervenção do Homem no tempo vivido e, ao mesmo tempo,permite o entendimento dos próprios relatos em torno dos quais a sociedadese estrutura e através dos quais ela olha para si mesma. O desafio de suafeitura, no entanto, situa-se fora do espaço e do tempo específicos do país:percorre o traçado da moderna civilização capitalista (séc. XVI), estende-sepelos vários momentos do séc. XIX e culmina com o painel contemporâneonacional e internacional. O projeto proposto privilegia três objetos de estudo:a imprensa, o rádio e a televisão.Palavras-chaves: História da cultura, história dos meios de comunicação,imprensa, rádio, televisão

    Order preserving pattern matching on trees and DAGs

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    The order preserving pattern matching (OPPM) problem is, given a pattern string pp and a text string tt, find all substrings of tt which have the same relative orders as pp. In this paper, we consider two variants of the OPPM problem where a set of text strings is given as a tree or a DAG. We show that the OPPM problem for a single pattern pp of length mm and a text tree TT of size NN can be solved in O(m+N)O(m+N) time if the characters of pp are drawn from an integer alphabet of polynomial size. The time complexity becomes O(mlogm+N)O(m \log m + N) if the pattern pp is over a general ordered alphabet. We then show that the OPPM problem for a single pattern and a text DAG is NP-complete

    Seismic modelling and ava analysis of hidrocarbon traps

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    In this study, forward seismic modelling of four geological models with Hydrocarbon (HC) traps were performed by ray tracing method to produce synthetic seismogram of each model. The idea is to identify the Hydrocarbon Indicators (HCI‟s) such as bright spot, flat spot, dim spot and Bottom Simulating Reflector (BSR) in the synthethic seismogram. The modelling was performed in DISCO/FOCUS 5.0 seismic data processing programme. Strong positive and negative reflection amplitudes and some artifact reflection horizons were observed on produced seismograms due to rapid changes in subsurface velocity and geometry respectively Additionally, Amplitude-versus-angle (AVA) curves of each HCIs was calculated by the Crewes Zoeppritz Explorer programme. AVA curves show that how the reflection coefficients change with the density and the P and S wave velocities of each layer such as oil, gas, gas hydrate or water saturated sediments. Due to AVA curves, an increase in reflection amplitude with incident angle of seismic waves corresponds to an indicator of a hydrocarbon reservoi

    The Relationships between Religiosity and Internalizing Symptoms in African American Parent-Adolescent Dyads

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    Objectives: African American (AA) adolescents face a greater risk of internalizing symptoms, including symptoms of both depression and anxiety, compared with other racial groups; yet, relatively less is known about the variables that contribute to internalizing symptoms. With the aim of advancing this work, this study examined factors that may buffer against such symptoms (maternal warmth, religiosity), as well as those that may confer additional risk (maternal psychopathology). Method: One hundred ninety-three AA single mothers and their adolescent youth reported on religiosity, maternal warmth and depressive symptoms, and youth internalizing symptoms. Dyadic structural equation modeling was used to examine the effects of mother and adolescent religiosity, maternal warmth, maternal depressive symptoms, and adolescent age on youth internalizing symptoms as reported by both the mother and the adolescent. Results: Consistent with hypotheses, maternal depressive symptoms were significantly associated with youth internalizing symptoms (as reported by the adolescent). Further, the impact of maternal religiosity on self-reported youth internalizing symptoms and its subscales was moderated by adolescent age. Specifically, maternal religiosity was associated with fewer self-reported internalizing symptoms in young adolescents, whereas the effect waned in older youth. Conclusions: Possible predictive coprocesses such as maternal influence on adolescent religious choices and identity formation are explored in the context of adolescent internalizing symptomatology
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