157 research outputs found

    Higher-order asymptotic corrections and their application to the Gamma Variance Model

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    We present improved methods for calculating confidence intervals and pp-values in a specific class of statistical model that can incorporate uncertainties in parameters that themselves represent uncertainties (informally, ``errors on errors'') called the Gamma Variance Model (GVM). This model contains fixed parameters, generically called ε\varepsilon, that represent the relative uncertainties in estimates of standard deviations of Gaussian distributed measurements. If the ε\varepsilon parameters are small, one can construct confidence intervals and pp-values using standard asymptotic methods. This is formally similar to the familiar situation of a large data sample, in which estimators for all adjustable parameters have Gaussian distributions. Here we address the important case where the ε\varepsilon parameters are not small and as a consequence the asymptotic distributions do not represent a good approximation. We investigate improved test statistics based on the technology of higher-order asymptotics (pp^* approximation and Bartlett correction).Comment: 22 pages, 8 figure

    Evaluación de la capacidad biocontroladora de Trichoderma sp. en un cultivo de garbanzo (Cicer arietinum) en la región semiárida de la Provincia de Córdoba

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    Trabajo Final Integrador (Área de Consolidación Sistemas Agrícolas de Producción Extensivos - Ingeniería Agrónomica) -- UNC- Facultad de Ciencias Agropecuarias, 2018En este trabajo se busca evaluar la capacidad biocontroladora de Trichoderma sp. en un cultivo de garbanzo (Cicer arietinum) en la región semiárida de la provincia de Córdoba. Además, con diferentes formas de aplicación del mismo. Trichoderma spp es un agente biocontrolador fúngico y un estimulante vegetal el cual surge como una alternativa al uso de agroquímicos. Para el estudio se llevó acabo un ensayo experimental con diseño en bloques, en macroparcelas con 3 surcos por tratamiento de 150 metros de longitud y testigos apareados. Los tratamientos consisten en: Semilla Chorreada con Trichoderma sp.; Semilla con Biopolímero; Semilla Testigo; Semilla con Trichoderma sp.; Semilla con Fungicida; Semilla con Trichoderma sp + Chorreado con Trichoderma sp. Durante el transcurso de la prueba se fueron evaluando distintos parámetros como porcentaje de germinación, altura de plántula, plantas por metro cuadrado, incidencia de enfermedades, rendimiento y calibre. Realizados en sucesivas visitas al campo, complementando todo esto con test a laboratorio. Del trabajo se concluyó que el encapsulado de Tirchoderma en semillas con el biopolímero mejoró los parámetros fisiológicos de tamaño de plantas y rendimiento, posicionando al mismo de manera competitiva con respecto al tratamiento con fungicida

    Micronuclei formation in liver fibrosis samples from patients infected by hepatitis C virus

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    Genetic research on fibrosis outset and its progression in chronic hepatitis (CH) by hepatitis C virus (HCV) are limited. The lack of cytogenetic data led us to investigate the presence of micronuclei (MNi), as a sign of genomic damage. Hepatocytes of hepatic parenchyma from 62 cases diagnosed with CH associated with HCV and displaying different degrees of fibrosis (F1-F4) were analyzed. These data were compared to 15 cases without fibrosis (F0). Twelve healthy liver parenchyma samples were included as control. All samples were obtained from paraffin-embedded archival material. Micronucleated hepatocytes (MN-Heps) were analyzed through Feulgen/Fast-green staining. Results showed that the rates of MN-Heps in the F4 group were statistically significant (p < 0.05) and higher than those in the control group. Like results were also obtained on comparing F4 with F0, F1, F2 and F3 cases. Conversely, differences were not significant (p > 0.05) on comparing F0, F1, F2, F3, one against the other, as well as individual versus control. Although chromosomal losses in CH were detected, it was shown that liver parenchyma with fibrosis in the initial stages (F1-F3) cannot be considered cytogenetically abnormal

    Nationwide genetic analysis of more than 600 families with inherited eye diseases in Argentina

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    This study corresponds to the first large-scale genetic analysis of inherited eye diseases (IED) in Argentina and describes the comprehensive genetic profile of a large cohort of patients. Medical records of 22 ophthalmology and genetics services throughout 13 Argentinian provinces were analyzed retrospectively. Patients with a clinical diagnosis of an ophthalmic genetic disease and a history of genetic testing were included. Medical, ophthalmological and family history was collected. A total of 773 patients from 637 families were included, with 98% having inherited retinal disease. The most common phenotype was retinitis pigmentosa (RP, 62%). Causative variants were detected in 379 (59%) patients. USH2A, RPGR, and ABCA4 were the most common disease-associated genes. USH2A was the most frequent gene associated with RP, RDH12 early-onset severe retinal dystrophy, ABCA4 Stargardt disease, PROM1 cone-rod dystrophy, and BEST1 macular dystrophy. The most frequent variants were RPGR c.1345 C > T, p.(Arg449*) and USH2A c.15089 C > A, p.(Ser5030*). The study revealed 156/448 (35%) previously unreported pathogenic/likely pathogenic variants and 8 possible founder mutations. We present the genetic landscape of IED in Argentina and the largest cohort in South America. This data will serve as a reference for future genetic studies, aid diagnosis, inform counseling, and assist in addressing the largely unmet need for clinical trials to be conducted in the region

    ECVAM retrospective validation of in vitro micronucleus test (MNT)

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    In the past decade several studies comparing the in vitro chromosome aberration test (CAT) and the in vitro micronucleus test (MNT) were performed. A high correlation was observed in each of the studies (>85%); however, no formal validation for the micronucleus in vitro assay had been carried out. Therefore, a working group was established by the European Centre for the Validation of Alternative Methods (ECVAM) to perform a retrospective validation of the existing data, in order to evaluate the validity of the in vitro MNT on the basis of the modular validation approach. The primary focus of this retrospective validation was on the evaluation of the potential of the in vitro MNT as alternative to the standard in vitro CAT. The working group evaluated, in a first step, the available published data and came to the conclusion that two studies [German ring trial, von der Hude, W., Kalweit, S., Engelhardt, G. et al. (2000) In-vitro micronucleus assay with Chinese hamster V79 cells: results of a collaborative study with 26 chemicals. Mutat. Res., 468, 137–163, and SFTG International Collaborative Study, Lorge, E., Thybaud, V., Aardema, M., Oliver, J., Wataka, A., Lorenzon, G. and Marzin, D. (2006) SFTG International Collaborative Study on in-vitro micronucleus test I. General conditions and overall conclusions of the study. Mutat. Res., 607, 13–36] met the criteria for a retrospective validation according to the criteria previously defined by the working group. These two studies were evaluated in depth (including the reanalysis of raw data) and provided the information required for assessing the reliability (reproducibility) of the test. For the assessment of the concordance between the in vitro MNT and the in vitro CAT, additional published data were considered. Based on this retrospective validation, the ECVAM Validation Management Team concluded that the in vitro MNT is reliable and relevant and can therefore be used as an alternative method to the in vitro CAT. Following peer review, these conclusions were formally endorsed by the ECVAM Scientific Advisory Committee

    Search for Nearly Mass-Degenerate Higgsinos Using Low-Momentum Mildly Displaced Tracks in pp Collisions at sqrt(s)=13 TeV with the ATLAS Detector

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    Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at s = 13 TeV with the ATLAS detector

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    A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at = 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, , and tb) or third-generation leptons (τν and ττ) are included in this kind of combination for the first time. A simplified model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confidence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion

    Measurement of vector boson production cross sections and their ratios using pp collisions at s=13.6 TeV with the ATLAS detector

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