17,822 research outputs found
Posterior moments and quantiles for the normal location model with Laplace prior
We derive explicit expressions for arbitrary moments and quantiles of the posterior distribution of the location parameter eta in the normal location model with Laplace prior, and use the results to approximate the posterior distribution of sums of independent copies of eta
On the heating of source of the Orion KL hot core
We present images of the J=10-9 rotational lines of HC3N in the vibrationally
excited levels 1v7, 1v6 and 1v5 of the hot core (HC) in Orion KL. The images
show that the spatial distribution and the size emission from the 1v7 and 1v5
levels are different. While the J=10-9 1v7 line has a size of 4''x 6'' and
peaks 1.1'' NE of the 3 mm continuum peak, the J=10--9 1v5 line emission is
unresolved (<3'') and peaks 1.3'' south of the 3 mm peak. This is a clear
indication that the HC is composed of condensations with very different
temperatures (170 K for the 1v7 peak and K for the 1v5 peak). The
temperature derived from the 1v7 and 1v5 lines increases with the projected
distance to the suspected main heating source I. Projection effects along the
line of sight could explain the temperature gradient as produced by source I.
However, the large luminosity required for source I, >5 10^5 Lsolar, to explain
the 1v5 line suggests that external heating by this source may not dominate the
heating of the HC. Simple model calculations of the vibrationally excited
emission indicate that the HC can be internally heated by a source with a
luminosity of 10^5 Lsolar, located 1.2'' SW of the 1v5 line peak (1.8'' south
of source I). We also report the first detection of high-velocity gas from
vibrationally excited HC3N emission. Based on excitation arguments we conclude
that the main heating source is also driving the molecular outflow. We
speculate that all the data presented in this letter and the IR images are
consistent with a young massive protostar embedded in an edge-on disk.Comment: 13 pages, 3 figures, To be published in Ap.J. Letter
Deep structure of the Tyrrhenian basin from 2-D joint refraction and reflection travel-time tomography of wide angle seismic data
Rifting of the Tyrrhenian Basin, a complex interaction among faulting , magmatism and mantle exhumation
Presence of iron in polymers extruded with corrosive contaminants or abrasive fillers
Off-site measurements of the dimensions of extruder screws are used to monitor their wear. This wear causes the presence of metals in the processed polymer. We detected the presence of iron in polymers processed with corrosive contaminants or abrasive fillers. To this end we processed poly(ethylene terephthalate), PET, pure or contaminated with poly(vinyl chloride), PVC, and other thermoplastics reinforced with glass fibers, talc or vegetal fibers, and analyzed the metals in the processed materials by X-ray fluorescence spectroscopy. We show that iron dispersed in the polymer melt is generated by corrosion from the PET contaminated with PVC and by erosion from abrasive fillers. The contents of iron in the extruded polymers clearly indicate equipment wear. This contaminant acts as a polymer pro-degradant, decreasing its lifetime. Additionally, we show that the lower concentration of iron for composites with vegetal fibers indicates a lower abrasion in comparison to talc and glass fibers292FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2010/17804-
On the Practical Use in Hydrography of Filtered Daily Values of Mean Sea Level
It is shown that the mean monthly sea level of a non-permanent station can be referred to the long-term sea level of a permanent one when tidal stations are influenced by similar meteorological and oceanographical effects. Practical methods are derived : one is based on the direct transference and the other based on the ratio of the variances of the daily mean sea level. Applications of the methods are made for the ports of Cananeia, Ubatuba, Santos and Ilha Grande on the southern coast of Brazil
Ensaio em vasos com leguminosas num delineamento em 'spli-plot', onde ocorreu perda de parcela.
Verificar os efeitos de adubação em 11 tipos de solos da Rod. BR-319 e um de Matão-SP, utilizando-se Galactia striata IRI-2961 e Centrosema pubescens IRI1282, como plantas indicadoras
Weighted-Average Least Squares (WALS): Confidence and Prediction Intervals
We consider inference for linear regression models estimated by weighted-average least squares (WALS), a frequentist model averaging approach with a Bayesian flavor. We propose a new simulation method that yields re-centered confidence and prediction intervals by exploiting the bias-corrected posterior mean as a frequentist
estimator of a normal location parameter. We investigate the performance of WALS and several alternative estimators in an extensive set of Monte Carlo experiments that allow for increasing complexity of the model space and heteroskedastic, skewed, and thick-tailed regression errors. In addition to WALS, we include unrestricted
and fully restricted least squares, two post-selection estimators based on classical information criteria, a penalization estimator, and Mallows and jackknife model averaging estimators. We show that, compared to the other approaches, WALS performs well in terms of the mean squared error of point estimates, and also in
terms of coverage errors and lengths of confidence and prediction intervals
A Brazilian glycoprotein E-negative bovine herpesvirus type 1.2a (BHV-1.2a) mutant is attenuated for cattle and induces protection against wild-type virus challenge
The authors previously reported the construction of a glycoprotein E-deleted (gE-) mutant of bovine herpesvirus type 1.2a (BHV-1.2a). This mutant, 265gE-, was designed as a vaccinal strain for differential vaccines, allowing the distinction between vaccinated and naturally infected cattle. In order to determine the safety and efficacy of this candidate vaccine virus, a group of calves was inoculated with 265gE-. The virus was detected in secretions of inoculated calves to lower titres and for a shorter period than the parental virus inoculated in control calves. Twenty one days after inoculation, the calves were challenged with the wild type parental virus. Only mild signs of infection were detected on vaccinated calves, whereas non-vaccinated controls displayed intense rhinotracheitis and shed virus for longer and to higher titres than vaccinated calves. Six months after vaccination, both vaccinated and control groups were subjected to reactivation of potentially latent virus. The mutant 265gE- could not be reactivated from vaccinated calves. The clinical signs observed, following the reactivation of the parental virus, were again much milder on vaccinated than on non-vaccinated calves. Moreover, parental virus shedding was considerably reduced on vaccinated calves at reactivation. In view of its attenuation, immunogenicity and protective effect upon challenge and reactivation with a virulent BHV-1, the mutant 265gE- was shown to be suitable for use as a BHV-1 differential vaccine viru
An analysis of the first-arrival times picked on the DSS and wide-angle seismic section recorded in Italy since 1968
We performed an analysis of refraction data recorded in Italy since 1968 in the frame of the numerous deep seismic
sounding and wide-angle reflection/refraction projects. The aims of this study are to construct a parametric
database including the recording geometric information relative to each profile, the phase pickings and the results
of some kinematic analyses performed on the data, and to define a reference 1D velocity model for the Italian
territory from all the available refraction data. As concerns the first goal, for each seismic section we picked
the P-wave first-arrival-times, evaluated the uncertainties of the arrival-times pickings and determined from each
travel time-offset curve the 1D velocity model. The study was performed on 419 seismic sections. Picking was
carried out manually by an algorithm which includes the computation of three picking functions and the picking-
error estimation. For each of the travel time-offset curves a 1D velocity model has been calculated. Actually,
the 1D velocity-depth functions were estimated in three different ways which assume: a constant velocitygradient
model, a varying velocity-gradient model and a layered model. As regards the second objective of this
work, a mean 1D velocity model for the Italian crust was defined and compared with those used for earthquake
hypocentre locations and seismic tomographic studies by different institutions operating in the Italian area, to
assess the significance of the model obtained. This model can be used in future works as input for a next joint
tomographic inversion of active and passive seismic data
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