Serum immunoglobulins in children perinatally exposed to human immunodeficiency virus

OBJECTIVE: Hypergammaglobulinemia is an early manifestation of perinatal HIV infection. Our objective was to analyze the differences in serum immunoglobulin levels between infected and seroreverting children and their association with clinical outcome. METHODS: We carried out a historical prospective study with 107 infected and 90 seroreverting children. We compared the IgA, IgG, and IgM levels between infected and seroreverting patients within the first 18 months of life; IgA, IgG, and IgM as surrogate markers of infection; and IgA, IgG, and IgM levels within the first 5 years in infected children, according to clinical outcome. The Mann-Whitney test was used for comparison between groups. Surrogate markers were assessed according to sensitivity, specificity, positive and negative predictive values, and Youden's index. RESULTS: Infected children, when compared to seroreverters, showed significantly higher levels of IgM between the 1st and 5th trimesters; IgA and IgG between the 2nd and 6th trimesters (P less than or equal to 0.05). Levels of IgA greater than or equal to 90 mg/dl in the 2nd trimester and IgG greater than or equal to 1,700 mg/dl or 1,200 mg/dl in the 2nd and 3rd trimesters were associated with HIV infection, with Youden's indexes of 0.97, 0.92, and 0.93, respectively. Infected children in the B and C categories, compared to those in the N and A, showed higher levels of IgM between the 2nd and 4th years, and IgA between the 3rd and 5th year (P > 0.05). CONCLUSIONS: The temporal progression of IgA, IgG, and IgM levels showed an early and intense stimulation to the synthesis of immunoglobulin in infected children. Clinical and epidemiological indicators showed that such levels may be surrogate markers of infection. Higher IgM and IgA levels between the 2nd and 5th years in more severely infected children suggest a dysfunction in immune regulation secondary to persistent antigenic stimulation.OBJETIVO: a hipergamaglobulinemia é uma manifestação precoce da infecção perinatal por HIV. O objetivo foi analisar as diferenças nos níveis séricos de imunoglobulinas entre crianças infectadas e sororreversoras, e sua associação com a evolução clínica. MÉTODOS: Em um estudo prospectivo histórico, avaliaram-se 107 crianças infectadas e 90 sororreversoras. Compararam-se: IgA, IgG e IgM entre infectados e sororreversores nos primeiros 18 meses de vida; IgA, IgG e IgM como marcadores indiretos de infecção; IgA, IgG e IgM nos 5 primeiros anos em infectados, de acordo com a evolução clínica. Utilizou-se o teste de Mann-Whitney para a comparação entre grupos. Na avaliação de marcadores indiretos, analisaram-se Sensibilidade, Especificidade, Valores Preditivos Positivo e Negativo, e índice J. RESULTADOS: Infectados, em relação a sororreversores, apresentaram níveis significativamente superiores de IgM, do 1o ao 5o trimestre; IgA e IgG, do 2o ao 6o trimestre (P 90 mg/dl no 2o trimestre e IgG > 1.700 mg/dl ou 1.200 mg/dl no 2o e 3o trimestres associaram-se à infecção por HIV com índices J de 0,97, 0,92 e 0,93, respectivamente. Crianças infectadas nas categorias B e C, comparadas àquelas nas categorias N e A, apresentaram níveis superiores de IgM, do 2o ao 4o ano e IgA, do 3o ao 5o ano (P £.0,05). CONCLUSÕES: A evolução temporal dos níveis de IgA, IgG e IgM demonstra um estímulo intenso e precoce à síntese de imunoglobulinas em infectados. Indicadores clínico-epidemiológicos demonstram que tais níveis podem ser marcadores indiretos de infecção. Níveis superiores de IgM e IgA do 2o ao 5o ano em crianças infectadas com maior gravidade sugerem disfunção na regulação imune secundária ao estímulo antigênico persistente.20921

Controlo químico de infestantes

Uma planta é considerada infestante quando nasce espontaneamente num local e momento indesejados, podendo interferir negativamente com a cultura instalada. As infestantes competem com as culturas para o espaço, a luz, água e nutrientes, podendo atrasar e prejudicar as operações de colheita, depreciar o produto final e assegurarem a reinfestação nas culturas seguintes. Dado o modo de propagação diferenciado das diversas espécies de infestantes, com as anuais a propagarem-se por semente e as perenes ou vivazes a assegurarem a sua propagação através de órgãos vegetativos (rizomas, bolbos, tubérculos, etc.), assim, também o seu controlo quer químico, quer mecânico terá que ser diferenciado, ou seja, para controlar infestantes anuais será suficiente destruir a sua parte aérea, enquanto para controlar infestantes perenes teremos que destruir os seus órgãos reprodutivos. O controlo de infestantes poderá ser químico, através da utilização de herbicidas, ou mecânico pela utilização de alfaias agrícolas, tais como a charrua de aivecas, a charrua de discos, a grade de discos, o escarificador e a fresa. Quando a técnica utilizada na instalação das culturas é a sementeira directa, o controlo das infestantes terá que ser obrigatoriamente químico, enquanto se o recurso à mobilização do solo for a técnica mais utilizada (sistema de mobilização tradicional ou sistema de mobilização reduzida), o controlo das infestantes tanto poderá ser químico como mecânico. Neste trabalho iremos abordar apenas, o controlo químico de infestantes

Measurement of differential cross sections for top quark pair production using the lepton plus jets final state in proton-proton collisions at 13 TeV

National Science Foundation (U.S.

Identification of heavy-flavour jets with the CMS detector in pp collisions at 13 TeV

Many measurements and searches for physics beyond the standard model at the LHC rely on the efficient identification of heavy-flavour jets, i.e. jets originating from bottom or charm quarks. In this paper, the discriminating variables and the algorithms used for heavy-flavour jet identification during the first years of operation of the CMS experiment in proton-proton collisions at a centre-of-mass energy of 13 TeV, are presented. Heavy-flavour jet identification algorithms have been improved compared to those used previously at centre-of-mass energies of 7 and 8 TeV. For jets with transverse momenta in the range expected in simulated $\mathrm{t}\overline{\mathrm{t}}$ events, these new developments result in an efficiency of 68% for the correct identification of a b jet for a probability of 1% of misidentifying a light-flavour jet. The improvement in relative efficiency at this misidentification probability is about 15%, compared to previous CMS algorithms. In addition, for the first time algorithms have been developed to identify jets containing two b hadrons in Lorentz-boosted event topologies, as well as to tag c jets. The large data sample recorded in 2016 at a centre-of-mass energy of 13 TeV has also allowed the development of new methods to measure the efficiency and misidentification probability of heavy-flavour jet identification algorithms. The heavy-flavour jet identification efficiency is measured with a precision of a few per cent at moderate jet transverse momenta (between 30 and 300 GeV) and about 5% at the highest jet transverse momenta (between 500 and 1000 GeV)

Particle-flow reconstruction and global event description with the CMS detector

The CMS apparatus was identified, a few years before the start of the LHC operation at CERN, to feature properties well suited to particle-flow (PF) reconstruction: a highly-segmented tracker, a fine-grained electromagnetic calorimeter, a hermetic hadron calorimeter, a strong magnetic field, and an excellent muon spectrometer. A fully-fledged PF reconstruction algorithm tuned to the CMS detector was therefore developed and has been consistently used in physics analyses for the first time at a hadron collider. For each collision, the comprehensive list of final-state particles identified and reconstructed by the algorithm provides a global event description that leads to unprecedented CMS performance for jet and hadronic tau decay reconstruction, missing transverse momentum determination, and electron and muon identification. This approach also allows particles from pileup interactions to be identified and enables efficient pileup mitigation methods. The data collected by CMS at a centre-of-mass energy of 8 TeV show excellent agreement with the simulation and confirm the superior PF performance at least up to an average of 20 pileup interactions

Search for heavy resonances decaying to a top quark and a bottom quark in the lepton+jets final state in proton–proton collisions at 13 TeV

info:eu-repo/semantics/publishe

Evidence for the Higgs boson decay to a bottom quark–antiquark pair

info:eu-repo/semantics/publishe