Averaged Singular Integral Estimation as a Bias Reduction Technique

This paper proposes an averaged version of singular integral estimators, whose bias achieves higher rates of convergence under smoothing assumptions. We derive exact bias bounds, without imposing smoothing assumptions, which are a basis for deriving the rates of convergence under differentiability assumptions.Publicad

Bogdanov-Takens resonance in time-delayed systems

We analyze the oscillatory dynamics of a time-delayed dynamical system subjected to a periodic external forcing. We show that, for certain values of the delay, the response can be greatly enhanced by a very small forcing amplitude. This phenomenon is related to the presence of a Bogdanov- Takens bifurcation and displays some analogies to other resonance phenomena, but also substantial differences.Comment: 14 pages, 8 figure

Global rates of convergence for the bias of singular integral estimators and their shifted versions

This paper provides global rates of convergence for the bias of singular integral estimators of a probability density function under weak conditions, which avoid differentiability. It is also shown that, under smoothing conditions, shifting the singular integral estimators provides a bias reduction technique

On universal unbiasedness of delta estimators

This paper considers delta estimators of a Radon-Nicodym derivative of a probability function with respect to a measure. Sufficient conditions for asymptotic unbiasedness and global rates of convergence, which can be improved by imposing differentiability conditions on the estimated curves, are provided. A bias reduction technique is proposed, and the application of the results to regression estimation is discussed. The sufficient conditions for asymptotic unbiasedness are checked for some broad classes of nonparametric estimators

Considerations in Determining the Cost of Measurement Uncertainty Associated with Dimensional Tolerances Verification

The verification of compliance with a design specification in manufacturing requires the use of metrological instruments to check if the magnitude associated with the design specification is or not according with tolerance range. Such instrumentation and their use during the measurement process, has associated an uncertainty of measurement whose value must be related to the value of tolerance tested. Most papers dealing jointly tolerance and measurement uncertainties are mainly focused on the establishment of a relationship uncertainty-tolerance without paying much attention to the impact from the standpoint of process cost. This paper analyzes the cost-measurement uncertainty, considering uncertainty as a productive factor in the process outcome. This is done starting from a cost-tolerance model associated with the process. By means of this model the existence of a measurement uncertainty is calculated in quantitative terms of cost and its impact on the process is analyzed

Initiation codon selection is accomplished by a scanning mechanism without crucial initiation factors in sindbis virus subgenomic mRNA

Translation initiation of alphavirus subgenomic mRNA (sgmRNA) can occur in the absence of several initiation factors (eIFs) in infected cells; however, the precise translation mechanism is still poorly understood. In this study, we have examined the mechanism of initiation and AUG selection in Sindbis virus (SINV) sgmRNA. Our present findings suggest that sgmRNA is translated via a scanning mechanism, since the presence of a hairpin structure before the initiation codon hampers protein synthesis directed by this mRNA. In addition, translation is partially recovered when an in-frame AUG codon is placed upstream of this hairpin. This scanning process takes place without the participation of eIF4A and active eIF2. These results, combined with our findings through modifying the SINV sgmRNA leader sequence, do not support the possibility of a direct initiation from the start codon without previous scanning, or a shunting mechanism. Moreover, studies carried out with sgmRNAs containing two alternative AUG codons within a good context for translation reveal differences in AUG selection which are dependent on the cellular context and the phosphorylation state of eIF2α. Thus, initiation at the additional AUG is strictly dependent on active eIF2, whereas the genuine AUG codon can start translation following eIF2α inactivation. Collectively, our results suggest that SINV sgmRNA is translated by a scanning mechanism without the potential participation of crucial eIFs. A model is presented that explains the mechanism of initiation of mRNAs bearing two alternative initiation codonsThis work was supported by a DGICYT (Dirección General de Investigación Científica y Técnica. Ministerio de Economía y Competitividad, Spain) grant BFU2012-31861. M.G.-M. is holder of a FPI (Formación de Personal Investigador) fellowship. The Institutional Grant awarded to the Centro de Biología Molecular “Severo Ochoa” (CSIC-UAM) by the Fundación Ramón Areces is acknowledge

Differences in Body Composition between Playing Positions in Men’s Professional Soccer: A Systematic Review with Meta-Analysis

The performance of male soccer players (MSPs) depends on multiple factors, such as body composition. It is understandable to think that, due to the physical demands and specific functions during play, body composition may vary depending on the playing position. The aim of this systematic review and meta-analysis was to describe the anthropometric, BC, and somatotype characteristics of professional MSPs and to compare the reported values according to playing position. We systematically searched Embase, PubMed, SPORTDiscus, and Web of Science following the PRISMA statement. Random-effects meta-analysis, a pooled summary of means, and 95% CI (method or equation) were calculated. Random models were used with the Restricted Maximum Likelihood (REML) method. Twenty-six articles were included in the systematic review and the meta-analysis. After comparing the groups according to the playing position (goalkeeper, defender, midfielder, and forward), significant differences were found in age, height, weight, the sum of skinfolds, kilograms of muscle mass, and kilograms of fat-free mass (p = 0.001; p < 0.0001). No significant differences were observed in fat mass, percentage of fat-free mass, percentage of muscle mass, bone mass, and somatotype. Despite the limitations, this study provides useful information to help medical–technical staff to properly assess the BC of professional MSPs, providing reference values for the different positions

Au/CeO2 metallic monolith catalysts: Influence of the metallic substrate

Ceria-based gold catalysts were successfully deposited on ferritic stainless steel (Fecralloy) and aluminium monoliths. The prepared monolithic and reference powder catalysts were characterized by means of S BET, X-ray diffraction, glow discharge optical emission spectroscopy and scanning electron microscopy-energy dispersive X-ray analysis techniques and tested in the CO oxidation reaction. Characterization results put in evidence the diffusion of cations from the catalytic layer on the surface of the monoliths to the metallic oxide scale and inversely, from the oxide scale to the catalysts, thus altering the catalytic formulation and affecting the CO oxidation properties of the catalytic device. The extension and nature of the modifications produced depend on the nature of the catalysts and the metallic substrate, as well as the reaction conditions applied. These facts must be considered when gold catalysts are supported on metallic-structured devices. © 2013 The Author(s).Peer Reviewe

Affinity partitioning of proteins tagged with choline-binding modules in aqueous two-phase systems

We present a novel procedure for affinity partitioning of recombinant proteins fused to the cholinebinding module C-LytA in aqueous two-phase systems containing poly(ethylene glycol) (PEG). Proteins tagged with the C-LytA module and exposed to the two-phase systems are quantitatively localized in the PEG-rich phase, whereas subsequent addition of the natural ligand choline specifically shifts their localization to the PEG-poor phase by displacement of the polymer from the binding sites. The described procedure is simple, scalable and reproducible, and has been successfully applied to the purification of four diverse proteins, resulting in high yields and purity