1,021 research outputs found

    Contribution of exclusive (π0π0,π0η,ηη)γ(\pi^0\pi^0, \pi^0\eta, \eta\eta)\gamma channels to the leading order HVP of the muon g2g-2

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    We evaluate the contributions of (π0π0,π0η,ηη)γ(\pi^0\pi^0, \pi^0\eta, \eta\eta)\gamma exclusive channels to the dispersion integral of the leading order HVP of the muon anomalous magnetic moment. These channels are included in some way in previous evaluations of the π0ω,ηω\pi^0\omega, \eta\omega and ηϕ\eta\phi contributions to aμhad,LOa_{\mu}^{\rm had, LO}, where the vector resonances (decaying into π0/η+γ\pi^0/\eta+ \gamma) are assumed to be on-shell. Since the separation of resonance and background contributions in a given observable is, in general, a model-dependent procedure, here we use pseudoscalar mesons and the photon as the inin and outout states of the e+e(π0π0,π0η,ηη)γe^+e^- \to (\pi^0\pi^0, \pi^0\eta, \eta\eta)\gamma SS-matrix, such that the cross section contains the interferences among different contributing to the amplitudes. We find aμhad,LO(P10P20γ)=(1.13±0.13)×1010a^{\rm had, LO}_{\mu}(P^0_1P^0_2\gamma)=(1.13\pm 0.13 ) \times 10^{-10}, where uncertainties stem mainly from vector meson dominance model parameters. Improved experimental studies of these exclusive channels in the whole range below 2 GeV would reduce model-dependency

    Preferential associated anomalies in 818 cases of microtia in South america

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    The etiology of microtia remains unknown in most cases. The identification of patterns of associated anomalies (i.e., other anomalies that occur with a given congenital anomaly in a higher than expected frequency), is a methodology that has been used for research into the etiology of birth defects. We conducted a study based on cases of microtia that were diagnosed from more than 5 million live (LB)- and stillbirths (SB) examined in hospitals participating in ECLAMC (Latin American Collaborative Study of Congenital Malformations) between 1967 and 2009. We identified 818 LB and SB with microtia and at least one additional non-related major congenital anomaly (cases) and 15,969 LB and SB with two or more unrelated major congenital anomalies except microtia (controls). A logistic regression analysis was performed to identify the congenital anomalies preferentially associated with microtia. Preferential associations were observed for 10 congenital anomalies, most of them in the craniofacial region, including facial asymmetry, choanal atresia, and eyelid colobomata. The analysis by type of microtia showed that for anomalies such as cleft lip and palate, macrostomia, and limb reduction defects, the frequency increased with the severity of the microtia. In contrast, for other anomalies the frequency tended to be the same across all types of microtia. Based on these results we will integrate data on the developmental pathways related to preferentially associated congenital anomalies for future studies investigating the etiology of microtia.Fil: Luquetti, Daniela V.. University of Washington; Estados Unidos. Seattle Children’s Research Institute; Estados UnidosFil: Cox, Thimoty C.. Monash University; Australia. University of Washington; Estados UnidosFil: López Camelo, Jorge Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. CEMIC-CONICET. Centro de Educaciones Médicas e Investigaciones Clínicas "Norberto Quirno". CEMIC-CONICET.; ArgentinaFil: Dutra, Maria da Graça. Instituto Oswaldo Cruz; BrasilFil: Cunningham, Michael L.. University of Washington; Estados Unidos. Seattle Children’s Research Institute; Estados UnidosFil: Castilla, Eduardo Enrique. Centro de Educación Médica e Investigaciones Clínicas “Norberto Quirno”; Argentina. Instituto Oswaldo Cruz; Brasil. Instituto Nacional de Genética Médica Populacional; Brasi

    Plan de negocios de una ludoteca en Zapopan, Jalisco

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    El presente trabajo muestra un plan de negocios de un establecimiento encargado de otorgar servicios de cuidado de niños con un concepto diferente al de los modelos tradicionales establecidos en la zona metropolitana de Guadalajara

    The impact of altitude on infant health in South America

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    Several studies report that altitude reduces birth weight. However, much remains unknown about effects in various altitude ranges and about the heterogeneity in altitude effects by fetal health endowments. This study estimates the effects of altitude in South America on the means and quantiles of birth weight and gestational age separately for two large samples born at altitude ranges of 5 to 1,280mand 1,854 to 3,600 m. The study finds significant negative altitude effects on birth weight and gestational age in the low-altitude sample and on birth weight in the high-altitude sample. Altitude effects are larger for infants with very low fetal health endowments. The study finds differences in the effects of several inputs such as socioeconomic status and maternal fertility history and health between the two altitude samples. The study highlights the importance of adverse altitude effects on infant health when evaluating the costs and returns of policies that change the number of individuals who reside at higher altitude in both low and high altitude ranges.Fil: Wehbya, George L.. University of Iowa; Estados UnidosFil: Castilla, Eduardo Enrique. Fundación Oswaldo Cruz; Brasil. Centro de Educación Medica E Invest.clinicas; ArgentinaFil: López Camelo, Jorge Santiago. Centro de Educación Médica e Investigaciones Clínicas "Norberto Quirno"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto Multidisciplinario de Biología Celular. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Instituto Multidisciplinario de Biología Celular. Universidad Nacional de La Plata. Instituto Multidisciplinario de Biología Celular; Argentin

    Ultra-broadband photon pair preparation by spontaneous four wave mixing in dispersion-engineered optical fiber

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    We present a study of the spectral properties of photon pairs generated through the process of spontaneous four wave mixing (SFWM) in single mode fiber. Our analysis assumes narrowband pumps, which are allowed to be frequency-degenerate or non-degenerate. Based on this analysis, we derive conditions on the pump frequencies and on the fiber dispersion parameters which guarantee the generation of ultra-broadband photon pairs. Such photon pairs are characterized by: i) a very large degree of entanglement, and ii) a very high degree of temporal synchronization between the signal and idler photons. Through a numerical exercise, we find that the use of photonic crystal fiber (PCF) facilitates the fulfilment of the conditions for ultra-broadband photon pair generation; in particular, the spectral region in which emission occurs can be adjusted to particular needs through an appropriate choice of the PCF parameters. In addition, we present a novel quantum interference effect, resulting from indistinguishable pathways to the same outcome, which can occur when pumping a SFWM source with multiple spectral lines.Comment: 15 pages, 10 figures. To be published in Phys. Rev.

    Prenatal care effectiveness and utilization in Brazil

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    The impact of prenatal care use on birth outcomes has been understudied in South American countries. This study assessed the effects of various measures of prenatal care use on birth weight (BW) and gestational age outcomes using samples of infants born without and with common birth defects from Brazil, and evaluated the demand for prenatal care. Prenatal visits improved BW in the group without birth defects through increasing both fetal growth rate and gestational age, but prenatal care visits had an insignificant effect on BW in the group with birth defects when adjusting for gestational age. Prenatal care delay had no effects on BW in both infant groups but increased preterm birth risk in the group without birth defects. Inadequate care versus intermediate care also increased LBW risk in the group without birth effects. Quantile regression analyses revealed that prenatal care visits had larger effects at low compared with high BW quantiles. Several other prenatal factors and covariates such as multivitamin use and number of previous live births had significant effects on the studied outcomes. The number of prenatal care visits was significantly affected by several maternal health and fertility indicators. Significant geographic differences in utilization were observed as well. The study suggests that more frequent use of prenatal care can increase BW significantly in Brazil, especially among pregnancies that are uncomplicated with birth defects but that are at high risk for low birth weight. Further research is needed to understand the effects of prenatal care use for pregnancies that are complicated with birth defects.Instituto Multidisciplinario de Biología Celula

    Activation of human lymphomononuclear cells by peptides derived from extracellular matrix proteins

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    AbstractA series of peptides of 15 amino acids with sequences contained in human extracellular matrix (ECM) proteins (fibronectin, laminin A, laminin B1, tenascin, undulin, α1-chain of type IV and VIII collagen and α2-chain of type VIII collagen) have been synthesized. The selected structures conformed to the following pattern: (i) Pro at position 6, (ii) Leu, Lys, Ile, Val, Ala or Gly at position 2, (iii) Glu or Asp at position 11. Fibronectin and the indicated peptides, when present in cultures of lymphomononuclear cells from healthy donors, promoted stimulation of monocytes manifested by a release of IL-1α, IL-1β, IL-6 and TNFα; an increase in the percentage of cells expressing CD14, CD16, CD11b and CD14/CD16; an increase in cytotoxicity against HT-29. Cytotoxicity against K562 and Daudi cells (targets of NK and LAK cells) was also observed together with an increase in the percentage of cells expressing CD56, CD56/CD16 (corresponding to NK cells), and CD56/CD8 (corresponding to NK-like lymphocytes), indicating a stimulation of lymphocytes. Activated monocytes and lymphocytes contained a large number of granules with DNAse activity. These results suggest that at least some of the immunological properties of ECM proteins could be accounted for by motifs fulfilling a characteristic sequence pattern shared by all of them

    FDG-PET studies of the effect of MDMA in rat brain

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    [Abstract] The 10th International Conference on Functional Mapping of the Human Brain, June 13-17, 2004, Budapest, HungaryAlterations of the human brain due to MDMA use are a focus of ongoing research. MDMA abuse produces both short and long-term effects on brain; MDMA-induced functional alterations of the serotonergic system are reported to alter local energy metabolism of cortical and subcortical structures. Presently, there are no FDG-PET experimental studies reported in animals. The aim of this study is to assess these brain glucose metabolism changes after a single dose of MDMA in rats by using FDG-PETPublicad

    Quantile effects of prenatal care utilization on birth weight in Argentina

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    The effects of prenatal care utilization on birth weight (BW) may vary by unobserved fetal health endowments. This heterogeneity will be masked by estimating the effects at BW mean but can be evaluated by estimating the effects at BW quantiles as fetal health endowment is a strong correlate with the BW quantile order. We estimated the effects of prenatal care visits and delay before prenatal care initiation, on BW mean and quantiles using a sample of infants from Argentina. Self-selection into prenatal care was modeled using 2SLS and instrumental variable quantile regression. Results suggest that the 'mean' effect of prenatal care utilization largely underestimates the effects at lower BW quantiles. About 35 and 77 g increase in BW mean and 0.1 quantile respectively, per visit and about 30 and 139 g decrease in BW mean and 0.1 quantile respectively, per week delayed, were estimated. Ignoring self-selection into prenatal care resulted in underestimation of mean and quantile effects. Results highlight the limitation of analyses focused on 'mean effects' in the presence of treatment heterogeneity and emphasize the importance of identifying women at risk for having infants at lower BW quantiles as they may benefit most from earlier and more intensive prenatal care.Instituto Multidisciplinario de Biología Celula
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