1,951 research outputs found
A modified Brazilian test for the generalized-fracturetoughness determination in multimaterial corners. Numerical and experimental results
IX CONGRESO NACIONAL DE
MATERIALES COMPUESTOS. Celebrado en
Girona, 5, 6, 7 y 8 de julio de 2011In the present work, a general procedure for the experimental evaluation of the
generalized fracture toughness in multimaterial corners is defined. The proposed
method is suitable for closed corners (all material wedges being bonded) having two
singular terms in the asymptotic stress representation at the corner tip. For a particular
corner configuration, the method finds the load configuration at which one of the
singular terms vanishes, thus the main stress contribution being controlled by the other
non-vanishing singular term. The experimental test, until failure, using the previously
defined load configuration allows the generalized fracture toughness associated to each
singular term to be evaluated. The whole procedure has been applied to a bimaterial
CFRP-Adhesive bimaterial corner and the generalized fracture toughness values have
been obtained. The testing of mixed modes has permitted a failure envelope based on
the generalized fracture toughness values at the corner tip to be defined. Previously
published results, with different geometries, but involving the same corner, have shown
that the failure envelope can predict accurately the failure initiation at these corners.Junta de Andalucía y Fondo Social Europeo P08-TEP-4071Junta de Andalucía y Fondo Social Europeo P08-TEP-4051Ministerio de Ciencia e Innovación MAT2009-14022CAPES Ministerio de Educación de Brasi
To work or not to work? Immigrant women and work between constraints and opportunities : a comparison between Lombardy and Cataluña
The aim of this article is to analyse how family constraints, in term of gender roles and child-care responsibilities, affect the behaviour and attitudes of immigrant women towards work, comparing Italy (Lombardy) and Spain (Barcelona). Moreover, personal skills, the economic crisis, and the limited job opportunities for migrants (who access mostly low-qualified jobs) also play a role in the employment status of immigrant women. Therefore, we are interested in understanding the reasons that make women decide to work (or seek a job) or not, and how they feel about their work or their unemployed status. We will analyse 72 interviews (47 in Italy and 25 in Spain) with working and non-working women of different nationalities, taking into account years of staying in the hosting country, family composition, level of education, and kind of job, in order to combine these different aspects with the attitudes and outcomes towards work
Blue outliers among intermediate redshift quasars
[Oiii]{\lambda}{\lambda}4959,5007 "blue outliers" -- that are suggestive of
outflows in the narrow line region of quasars -- appear to be much more common
at intermediate z (high luminosity) than at low z. About 40% of quasars in a
Hamburg ESO intermediate-z sample of 52 sources qualify as blue outliers (i.e.,
quasars with [OIII] {\lambda}{\lambda}4959,5007 lines showing large systematic
blueshifts with respect to rest frame). We discuss major findings on what has
become an intriguing field in active galactic nuclei research and stress the
relevance of blue outliers to feedback and host galaxy evolution.Comment: Accepted for publication in Astrophysics and Space Science, Special
Issue on Line Shifts in Astrophysics and Laboratory Plasm
Charge Conjugation from Space-Time Inversion
We show that the CPT group of the Dirac field emerges naturally from the PT
and P (or T) subgroups of the Lorentz group.Comment: 4 pages, no figure
A Megacam Survey of Outer Halo Satellites. IV. Two foreground populations possibly associated with the Monoceros substructure in the direction of NGC2419 and Koposov2
The origin of the Galactic halo stellar structure known as the Monoceros ring
is still under debate. In this work, we study that halo substructure using deep
CFHT wide-field photometry obtained for the globular clusters NGC2419 and
Koposov2, where the presence of Monoceros becomes significant because of their
coincident projected position. Using Sloan Digital Sky Survey photometry and
spectroscopy in the area surrounding these globulars and beyond, where the same
Monoceros population is detected, we conclude that a second feature, not likely
to be associated with Milky Way disk stars along the line-of-sight, is present
as foreground population. Our analysis suggests that the Monoceros ring might
be composed of an old stellar population of age t ~ 9Gyr and a new component ~
4Gyr younger at the same heliocentric distance. Alternatively, this detection
might be associated with a second wrap of Monoceros in that direction of the
sky and also indicate a metallicity spread in the ring. The detection of such a
low-density feature in other sections of this halo substructure will shed light
on its nature.Comment: 10 pages, 10 figures, accepted for publication in Ap
Essential and checkpoint functions of budding yeast ATM and ATR during meiotic prophase are facilitated by differential phosphorylation of a meiotic adaptor protein, Hop1
A hallmark of the conserved ATM/ATR signalling is its ability to mediate a wide range of functions utilizing only a limited number of adaptors and effector kinases. During meiosis, Tel1 and Mec1, the budding yeast ATM and ATR, respectively, rely on a meiotic adaptor protein Hop1, a 53BP1/Rad9 functional analog, and its associated kinase Mek1, a CHK2/Rad53-paralog, to mediate multiple functions: control of the formation and repair of programmed meiotic DNA double strand breaks, enforcement of inter-homolog bias, regulation of meiotic progression, and implementation of checkpoint responses. Here, we present evidence that the multi-functionality of the Tel1/Mec1-to-Hop1/Mek1 signalling depends on stepwise activation of Mek1 that is mediated by Tel1/Mec1 phosphorylation of two specific residues within Hop1: phosphorylation at the threonine 318 (T318) ensures the transient basal level Mek1 activation required for viable spore formation during unperturbed meiosis. Phosphorylation at the serine 298 (S298) promotes stable Hop1-Mek1 interaction on chromosomes following the initial phospho-T318 mediated Mek1 recruitment. In the absence of Dmc1, the phospho-S298 also promotes Mek1 hyper-activation necessary for implementing meiotic checkpoint arrest. Taking these observations together, we propose that the Hop1 phospho-T318 and phospho-S298 constitute key components of the Tel1/Mec1- based meiotic recombination surveillance (MRS) network and facilitate effective coupling of meiotic recombination and progression during both unperturbed and challenged meiosis
Black hole mass estimates in quasars - A comparative analysis of high- and low-ionization lines
The inter-line comparison between high- and low-ionization emission lines has
yielded a wealth of information on the quasar broad line region (BLR) structure
and dynamics, including perhaps the earliest unambiguous evidence in favor of a
disk + wind structure in radio-quiet quasars. We carried out an analysis of the
CIV 1549 and Hbeta line profiles of 28 Hamburg-ESO high luminosity quasars and
of 48 low-z, low luminosity sources in order to test whether the
high-ionization line CIV 1549 width could be correlated with Hbeta and be used
as a virial broadening estimator. We analyze intermediate- to high-S/N,
moderate resolution optical and NIR spectra covering the redshifted CIV and
H over a broad range of luminosity log L ~ 44 - 48.5 [erg/s] and
redshift (0 - 3), following an approach based on the quasar main sequence. The
present analysis indicates that the line width of CIV 1549 is not immediately
offering a virial broadening estimator equivalent to H. At the same time
a virialized part of the BLR appears to be preserved even at the highest
luminosities. We suggest a correction to FWHM(CIV) for Eddington ratio (using
the CIV blueshift as a proxy) and luminosity effects that can be applied over
more than four dex in luminosity. Great care should be used in estimating
high-L black hole masses from CIV 1549 line width. However, once corrected
FWHM(CIV) values are used, a CIV-based scaling law can yield unbiased MBH
values with respect to the ones based on H with sample standard
deviation ~ 0.3 dex.Comment: 43 pages, 15 Figures, submitted to A&
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