10,573 research outputs found
Impact of observational uncertainties on universal scaling of MHD turbulence
Scaling exponents are the central quantitative prediction of theories of
turbulence and in-situ satellite observations of the high Reynolds number solar
wind flow have provided an extensive testbed of these. We propose a general,
instrument independent method to estimate the uncertainty of velocity field
fluctuations. We obtain the systematic shift that this uncertainty introduces
into the observed spectral exponent. This shift is essential for the correct
interpretation of observed scaling exponents. It is sufficient to explain the
contradiction between spectral features of the Elsasser fields observed in the
solar wind with both theoretical models and numerical simulations of
Magnetohydrodynamic turbulence
Adding gene transcripts into genomic prediction improves accuracy and reveals sampling time dependence.
Recent developments allowed generating multiple high-quality \u27omics\u27 data that could increase the predictive performance of genomic prediction for phenotypes and genetic merit in animals and plants. Here, we have assessed the performance of parametric and nonparametric models that leverage transcriptomics in genomic prediction for 13 complex traits recorded in 478 animals from an outbred mouse population. Parametric models were implemented using the best linear unbiased prediction, while nonparametric models were implemented using the gradient boosting machine algorithm. We also propose a new model named GTCBLUP that aims to remove between-omics-layer covariance from predictors, whereas its counterpart GTBLUP does not do that. While gradient boosting machine models captured more phenotypic variation, their predictive performance did not exceed the best linear unbiased prediction models for most traits. Models leveraging gene transcripts captured higher proportions of the phenotypic variance for almost all traits when these were measured closer to the moment of measuring gene transcripts in the liver. In most cases, the combination of layers was not able to outperform the best single-omics models to predict phenotypes. Using only gene transcripts, the gradient boosting machine model was able to outperform best linear unbiased prediction for most traits except body weight, but the same pattern was not observed when using both single nucleotide polymorphism genotypes and gene transcripts. Although the GTCBLUP model was not able to produce the most accurate phenotypic predictions, it showed the highest accuracies for breeding values for 9 out of 13 traits. We recommend using the GTBLUP model for prediction of phenotypes and using the GTCBLUP for prediction of breeding values
Prediction performance of linear models and gradient boosting machine on complex phenotypes in outbred mice.
We compared the performance of linear (GBLUP, BayesB, and elastic net) methods to a nonparametric tree-based ensemble (gradient boosting machine) method for genomic prediction of complex traits in mice. The dataset used contained genotypes for 50,112 SNP markers and phenotypes for 835 animals from 6 generations. Traits analyzed were bone mineral density, body weight at 10, 15, and 20 weeks, fat percentage, circulating cholesterol, glucose, insulin, triglycerides, and urine creatinine. The youngest generation was used as a validation subset, and predictions were based on all older generations. Model performance was evaluated by comparing predictions for animals in the validation subset against their adjusted phenotypes. Linear models outperformed gradient boosting machine for 7 out of 10 traits. For bone mineral density, cholesterol, and glucose, the gradient boosting machine model showed better prediction accuracy and lower relative root mean squared error than the linear models. Interestingly, for these 3 traits, there is evidence of a relevant portion of phenotypic variance being explained by epistatic effects. Using a subset of top markers selected from a gradient boosting machine model helped for some of the traits to improve the accuracy of prediction when these were fitted into linear and gradient boosting machine models. Our results indicate that gradient boosting machine is more strongly affected by data size and decreased connectedness between reference and validation sets than the linear models. Although the linear models outperformed gradient boosting machine for the polygenic traits, our results suggest that gradient boosting machine is a competitive method to predict complex traits with assumed epistatic effects
Anal manometric evaluation of children with encopresis
INTRODUÇÃO: A constipação crônica é doença comum na infância, ocorrendo em 5 a 10% dos pacientes pediátricos, considerada a segunda maior causa de procura nos consultórios de pediatria, sendo a encoprese decorrente de constipação grave associada à impactação fecal no reto. Dentre os exames diagnósticos, a manometria anal é utilizada para a avaliação de pacientes com distúrbios funcionais, como a constipação intestinal e a incontinência fecal, em alguns serviços para a avaliação de pacientes com encoprese, pois pode trazer informações sobre o mecanismo evacuatório e possíveis lesões esfincterianas anais. OBJETIVO: Verificar alterações manométricas em pacientes com encoprese. MÉTODOS: Foi realizado estudo de 40 manometrias anais de crianças constipadas com encoprese (G1) e 12 crianças constipados sem encoprese (G2). Foram obtidos os seguintes dados: pressões de repouso, contração e evacuação do canal anal e ampola retal, ponto de maior pressão, reflexo inibitório anal e sensibilidade retal. As manometrias foram realizadas com o aparelho Alacer de perfusão com 8 canais. RESULTADOS: Não foram encontradas diferenças nas pressões de repouso, contração e evacuação do canal anal entre os grupos. Chamou-nos a atenção a ausência de necessidade de maior volume retal para desencadear o reflexo inibitório anal. Não houve diferença da incidência de anismus entre os dois grupos, demonstrando que não se trata de fator importante na manutenção da encoprese, mas sim da constipação. CONCLUSÃO: Não houve necessidade de maior volume para desencadear o reflexo inibitório anal. O anismus não foi diferente entre os dois grupos, não sendo importante na manutenção da encoprese.INTRODUCTION: Chronic constipation is a common childhood disorder that affects 5 to 10% of pediatric patients, being the second most common cause for seeking medical help, with the encopresis arising out of severe constipation being associated with fecal impaction in the rectum. Among diagnostic exams, anal manometry is used to evaluate patients with functional disorders such as constipation and fecal incontinence, and in some procedures for the evaluation of patients suffering from encopresis, as it provides information on the defecation mechanism and any potential anal sphincter injuries. OBJECTIVE: To verify manometric alterations in patients with encopresis. METHODS: A study was conducted based on 40 anal manometries of constipated children with encopresis (G1) and 12 constipated children without encopresis (G2). The following data were obtained: pressure at rest, contraction and evacuation of the anal canal and the rectal ampulla, point of highest pressure, anal inhibitory reflex and rectal sensitivity. The manometries were performed with an 8-channel perfusion device manufactured by Alacer. DISCUSSION: No differences were found with respect for pressures at rest, contraction and evacuation of the anal canal between groups. Our attention was drawn to the lack of need for an increased rectal volume to trigger the anal inhibitory reflex. There was no difference in the incidence of anismus between groups, which shows that it is not a relevant factor in the maintenance of the encopresis, but of constipation. CONCLUSION: An increase in rectal volume was not required to trigger the anal inhibitory reflex. Anismus was not different in the two groups, being unimportant in the maintenance of encopresis
Hydration with sodium bicarbonate does not prevent contrast nephropathy: a multicenter clinical trial
BACKGROUND: Radiographic contrast media exposition can cause acute renal function impairment. There is limited and conflicting evidence that hydration with sodium bicarbonate prevents contrast-induced nephropathy (CIN) in patients undergoing cardiac catheterization. OBJECTIVE: The present study was aimed at determining whether sodium bicarbonate is superior to hydration with saline to prevent nephropathy in patients at risk undergoing cardiac catheterization. METHODS: Three hundred and one patients undergoing coronary angiography or percutaneous coronary intervention with serum creatinine > 1.2mg/dL or glomerular filtration rate (GFR) 1,2 mg/dL ou Taxa de Filtração Glomerular (TFG) < 50 mL/min, foram randomizados para receber hidratação com bicarbonato de sódio a partir de 1 hora antes do procedimento, e 6 horas após o procedimento, ou hidratação com solução salina a 0,9%. A NIC foi definida como um aumento de 0,5 mg/dL na creatinina em 48h. RESULTADOS: Dezoito pacientes (5,9%) desenvolveram nefropatia induzida por contraste: 9 pacientes no grupo do bicarbonato (6,1%) e 9 pacientes no grupo da solução salina (6,0%), p = 0,97. A variação na creatinina sérica foi semelhante em ambos os grupos, 0,01 ± 0,26 mg/dL no grupo do bicarbonato, e 0,01 ± 0,35 mg/dL no grupo da solução salina, p = 0,9. Não foi observada diferença estatística entre a alteração na taxa de filtração glomerular (0,89 ± 9 mL/ min vs. 2,29 ± 10 mL/min, p = 0,2, grupo do bicarbonato e grupo da solução salina, respectivamente). CONCLUSÃO: A hidratação com bicarbonato de sódio não foi superior ao soro fisiológico na prevenção a nefropatia induzida pelo contraste, em pacientes de risco submetidos a cateterismo cardíaco.PUCRS Hospital São LucasUNIFESP Hospital São PauloHospital São CamiloHospital General de PueblaHospital da UnimedHospital Intercath MeridionalUFRGSUNIFESP, Hospital São PauloSciEL
Genetic heterogeneity in the toxicity to systemic adenoviral gene transfer of interleukin-12
Despite the efficacy of IL-12 in cancer experimental models, clinical trials with systemic recombinant IL-12 showed unacceptable toxicity related to endogenous IFNgamma production. We report that systemic administration of a recombinant adenovirus encoding IL-12 (AdCMVmIL-12) has a dramatically different survival outcome in a number of mouse pure strains over a wide range of doses. For instance at 2.5 x 10(9) p.f.u., systemic AdCMVmIL-12 killed all C57BL/6 mice but spared all BALB/c mice. Much higher IFNgamma concentrations in serum samples of C57BL/6 than in those from identically treated BALB/c were found. Causes for heterogeneous toxicity can be traced to differences among murine strains in the levels of gene transduction achieved in the liver, as assessed with adenovirus coding for reporter genes. In accordance, IL-12 serum concentrations are higher in susceptible mice. In addition, sera from C57BL/6 mice treated with AdCMVmIL-12 showed higher levels of IL-18, a well-known IFNgamma inducer. Interestingly, lethal toxicity in C57BL/6 mice was abolished by administration of blocking anti-IFNgamma mAbs and also by simultaneous depletion of T cells, NK cells, and macrophages. These observations together with the great dispersion of IFNgamma produced by human PBMCs upon in vitro stimulation with IL-12, or infection with recombinant adenovirus encoding IL-12, suggest that patients might also show heterogeneous degrees of toxicity in response to IL-12 gene transfer
The Star Formation and Extinction Co-Evolution of UV-Selected Galaxies over 0.05<z<1.2
We use a new stacking technique to obtain mean mid IR and far IR to far UV
flux ratios over the rest near-UV/near-IR color-magnitude diagram. We employ
COMBO-17 redshifts and COMBO-17 optical, GALEX far and near UV, Spitzer IRAC
and MIPS Mid IR photometry. This technique permits us to probe infrared excess
(IRX), the ratio of far IR to far UV luminosity, and specific star formation
rate (SSFR) and their co-evolution over two orders of magnitude of stellar mass
and redshift 0.1<z<1.2. We find that the SSFR and the characteristic mass (M_0)
above which the SSFR drops increase with redshift (downsizing). At any given
epoch, IRX is an increasing function of mass up to M_0. Above this mass IRX
falls, suggesting gas exhaustion. In a given mass bin below M_0 IRX increases
with time in a fashion consistent with enrichment. We interpret these trends
using a simple model with a Schmidt-Kennicutt law and extinction that tracks
gas density and enrichment. We find that the average IRX and SSFR follows a
galaxy age parameter which is determined mainly by the galaxy mass and time
since formation. We conclude that blue sequence galaxies have properties which
show simple, systematic trends with mass and time such as the steady build-up
of heavy elements in the interstellar media of evolving galaxies and the
exhaustion of gas in galaxies that are evolving off the blue sequence. The IRX
represents a tool for selecting galaxies at various stages of evolution.Comment: Accepted for publication in GALEX Special Ap.J.Suppl., December, 200
Daratumumab in combination with urelumab to potentiate anti-myeloma activity in lymphocytedeficient mice reconstituted with human NK cells
Daratumumab is an anti-CD38 fully human IgG1 mAb approved for multiple myeloma treatment. One of the proposed mechanisms of action is the induction of antibody-dependent cellular cytotoxicity (ADCC) mediated by NK cells. NK cells acquire surface CD137 expression in the presence of solid-phase-attached daratumumab and when encountering a daratumumab-coated CD38+ tumor cell line. In this setting, addition of the agonist anti-CD137 mAb urelumab enhances NK-cell activation increasing CD25 expression and IFNɣ production. However, in vitro ADCC is not increased by the addition of urelumab both in 4h or 24h lasting experiments. To study urelumab-increased daratumumab-mediated ADCC activity in vivo, we set up a mouse model based on the intravenous administration of a luciferase-transfected multiple myeloma cell line of human origin, human NK cells and daratumumab to immuno-deficient NSG mice. In this model, intravenous administration of urelumab 24h after daratumumab delayed tumor growth and prolonged mice survival
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