5,168 research outputs found
Observations of SN2011fe with INTEGRAL
SN2011fe was detected by the Palomar Transient Factory on August 24th 2011 in
M101 few hours after the explosion. From the early spectra it was immediately
realized that it was a Type Ia supernova thus making this event the brightest
one discovered in the last twenty years. In this paper the observations
performed with the instruments on board of INTEGRAL (SPI, IBIS/ISGRI, JEM-X and
OMC) before and after the maximum of the optical light as well as the
interpretation in terms of the existing models of --ray emission from
such kind of supernovae are reported. All INTEGRAL high-energy have only been
able to provide upper limits to the expected emission due to the decay of
Ni. These bounds allow to reject explosions involving a massive white
dwarf in the sub--Chandrasekhar scenario. On the other hand, the optical light
curve obtained with the OMC camera suggests that the event was produced by a
delayed detonation of a CO white dwarf that produced M of
Ni. In this particular case, INTEGRAL would have only been able to
detect the early --ray emission if the supernova had occurred at a
distance of 2 -3 Mpc, although the brightest event could be visible up to
distances larger by a factor two.Comment: Proceedings of "An INTEGRAL view of the high-energy sky (the first 10
years)" the 9th INTEGRAL Workshop, October 15-19, 2012, Paris, France, in
Proceedings of Science (INTEGRAL 2012), Eds. A. Goldwurm, F. Lebrun and C.
Winkler, http://pos.sissa.it/cgi-bin/reader/conf.cgi?confid=176, id number
PoS (INTEGRAL 2012) 103 (2013
Group-IV graphene- and graphane-like nanosheets
We performed a first principles investigation on the structural and
electronic properties of group-IV (C, SiC, Si, Ge, and Sn) graphene-like sheets
in flat and buckled configurations and the respective hydrogenated or
fluorinated graphane-like ones. The analysis on the energetics, associated with
the formation of those structures, showed that fluorinated graphane-like sheets
are very stable, and should be easily synthesized in laboratory. We also
studied the changes on the properties of the graphene-like sheets, as result of
hydrogenation or fluorination. The interatomic distances in those graphane-like
sheets are consistent with the respective crystalline ones, a property that may
facilitate integration of those sheets within three-dimensional nanodevices
Characterisation of "Catalão" and "Salsichão" Portuguese traditional sausages with salt reduction
The present study evaluated the effect of salt reduction on traditional dry-cured sausages' safety, quality and
product acceptance, comprising physicochemical and microbiological parameters, biogenic amines, fatty acids,
texture profile and sensory analysis. According to our results, salt content had a major effect on microbiological
counts, although not compromising the products' safety. Marked differences were identified regarding biogenic
amines, in particular for histamine, tyramine and cadaverine, which were detected in larger amounts in products
with 3%. Moreover, significant differences in the fatty acids profile have also been found, but only in less abundant
components such as linoleic, lauric and heneicosanoic acids. Texture profile analysis of low-salt products,
revealed a decrease in hardness and chewiness, along with an increase in adhesiveness values. Sensory
evaluations revealed that despite the less intense aroma, products with 3% salt, had a more balanced salt
perception. Our results suggest that salt content may be reduced to 50% in dry-cured products, with the obvious
health-related advantages
SN 2002cv: A Heavily Obscured Type Ia Supernova
We present VRIJHK photometry, and optical and near-infrared spectroscopy, of
the heavily extinguished Type Ia supernova (SN) 2002cv, located in NGC 3190,
which is also the parent galaxy of the Type Ia SN 2002bo. SN 2002cv, not
visible in the blue, has a total visual extinction of 8.74 +- 0.21 mag. In
spite of this we were able to obtain the light curves between -10 and +207 days
from the maximum in the I band, and also to follow the spectral evolution,
deriving its key parameters. We found the peak I-band brightness to be Imax =
16.57 +- 0.10 mag, the maximum absolute I magnitude to be MmaxI = -18.79 +-
0.20, and the parameter dm15(B) specifying the width of the B-band light curve
to be 1.46 +- 0.17 mag. The latter was derived using the relations between this
parameter and dm40(I) and the time interval dtmax(I) between the two maxima in
the I-band light curve. As has been found for previously observed, highly
extinguished SNe Ia, a small value of 1.59 +- 0.07 was obtained here for the
ratio Rv of the total-to-selective extinction ratio for SN 2002cv, which
implies a small mean size for the grains along the line of sight toward us.
Since it was found for SN 2002bo a canonical value of 3.1, here we present a
clear evidence of different dust properties inside NGC 3190.Comment: 18 pages, 18 figures. Accepted for publication in MNRAS. Added
co-author
Recommended from our members
Beauty surveillance: the digital self-monitoring cultures of neoliberalism
This paper argues that ‘beauty apps’ are transforming the arena of appearance politics and foregrounds a theoretical architecture for critically understanding them. Informed by a feminist-Foucaultian framework, it argues that beauty apps offer a technology of gender which brings together digital self-monitoring and postfeminist modalities of subjecthood to produce an hitherto unprecedented regulatory gaze upon women that is marked by the intensification, extensification and psychologization of surveillance.
The paper is divided into four sections. First it introduces the literature on digital self-tracking. Secondly it sets out our understanding of neoliberalism and postfeminism. Thirdly it looks at beauty and surveillance, before offering, in the final section, a typology of appearance apps. This is followed by a discussion of the modes of address/authority deployed in these apps – especially what we call ‘surveillant sisterhood’ - and the kinds of entrepreneurial subjectivity they constitute. The paper seeks to make a contribution to feminist surveillance studies and argues that much more detailed research is needed to critically examine beauty apps
Antibody response against plasmid-encoded toxin (Pet) and the protein involved in intestinal colonization (Pic) in children with diarrhea produced by enteroaggregative Escherichia coli
Enteroaggregative Escherichia eoli (EAEC) is an emerging cause of pediatric and adult travellers diarrhea. the mechanism by which EAEC induce diarrhea is not completely known. Two serine protease autotransporter proteins, named Pet and Pic have been identified in EAEC strains. Pet has enterotoxic and cytotoxic activities, while the role of Pic in pathogenesis may lie on its mucinolytic activity. Little is known about Pet and Pic biological activities in vivo. in this study the antibody responses against these autotransporter proteins in convalescent children is investigated. Fifteen (83%) children showed specific antibodies against Pet or Pic in their sera. IgG and IgM antibodies were the main isotype found. Specific antibodies against Pic, but not against Pet, were detected in sera from age-matched control group. These data show that specific anti-Pet and anti-Pic antibodies are produced during the course of a natural EAEC infection in children. (C) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.Univ São Paulo, Dept Microbiol, Inst Ciencias Biomed, São Paulo, BrazilInst Butantan, Lab Especial Microbiol, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilUniv São Paulo, Fac Ciencias Farmaceut, Dept Anal Clin & Toxicol, BR-05508900 São Paulo, BrazilCINVESTAV, IPN, Dept Cell Biol, Mexico City 14000, DF, MexicoUniversidade Federal de São Paulo, Dept Microbiol Imunol & Parasitol, São Paulo, BrazilWeb of Scienc
Observation of SN2011fe with INTEGRAL. I. Pre--maximum phase
SN2011fe was detected by the Palomar Transient Factory on August 24th 2011 in
M101 a few hours after the explosion. From the early optical spectra it was
immediately realized that it was a Type Ia supernova thus making this event the
brightest one discovered in the last twenty years. The distance of the event
offered the rare opportunity to perform a detailed observation with the
instruments on board of INTEGRAL to detect the gamma-ray emission expected from
the decay chains of Ni. The observations were performed in two runs, one
before and around the optical maximum, aimed to detect the early emission from
the decay of Ni and another after this maximum aimed to detect the
emission of Co. The observations performed with the instruments on board
of INTEGRAL (SPI, IBIS/ISGRI, JEMX and OMC) have been analyzed and compared
with the existing models of gamma-ray emission from such kind of supernovae. In
this paper, the analysis of the gamma-ray emission has been restricted to the
first epoch. Both, SPI and IBIS/ISGRI, only provide upper-limits to the
expected emission due to the decay of Ni. These upper-limits on the
gamma-ray flux are of 7.1 10 ph/s/cm for the 158 keV line
and of 2.3 10 ph/s/cm for the 812 keV line. These bounds
allow to reject at the level explosions involving a massive white
dwarf, M in the sub--Chandrasekhar scenario and specifically
all models that would have substantial amounts of radioactive Ni in the
outer layers of the exploding star responsible of the SN2011fe event. The
optical light curve obtained with the OMC camera also suggests that SN2011fe
was the outcome of the explosion, possibly a delayed detonation although other
models are possible, of a CO white dwarf that synthesized M
of Ni. For this specific model.Comment: Accepted for publication in A&A. 10 pages, 10 figure
Effect of Layer-Stacking on the Electronic Structure of Graphene Nanoribbons
The evolution of electronic structure of graphene nanoribbons (GNRs) as a
function of the number of layers stacked together is investigated using
\textit{ab initio} density functional theory (DFT) including interlayer van der
Waals interactions. Multilayer armchair GNRs (AGNRs), similar to single-layer
AGNRs, exhibit three classes of band gaps depending on their width. In zigzag
GNRs (ZGNRs), the geometry relaxation resulting from interlayer interactions
plays a crucial role in determining the magnetic polarization and the band
structure. The antiferromagnetic (AF) interlayer coupling is more stable
compared to the ferromagnetic (FM) interlayer coupling. ZGNRs with the AF
in-layer and AF interlayer coupling have a finite band gap while ZGNRs with the
FM in-layer and AF interlayer coupling do not have a band gap. The ground state
of the bi-layer ZGNR is non-magnetic with a small but finite band gap. The
magnetic ordering is less stable in multilayer ZGNRs compared to single-layer
ZGNRs. The quasipartcle GW corrections are smaller for bilayer GNRs compared to
single-layer GNRs because of the reduced Coulomb effects in bilayer GNRs
compared to single-layer GNRs.Comment: 10 pages, 5 figure
Impact of salt reduction on biogenic amines, fatty acids, microbiota, texture and sensory profile in traditional blood dry-cured sausages
Meat industry needs to reduce salt in their products due to health issues. The present study evaluated the
effect of salt reduction from 6% to 3% in two Portuguese traditional blood dry-cured sausages. Physicochemical
and microbiological parameters, biogenic amines, fatty acids and texture profiles and sensory
panel evaluations were considered. Differences due to salt reduction were perceptible in a faint decline
of water activity, which slightly favoured microbial growth. Total biogenic amines content ranged from
88.86 to 796.68 mg kg 1 fresh matter, with higher amounts, particularly of cadaverine, histamine and
tyramine, in low-salt products. Still, histamine and other vasoactive amines remained at low levels, thus
not affecting consumers’ health. Regarding fatty acids, no significant differences were observed due to
salt. However, texture profile analysis revealed lower resilience and cohesiveness in low-salt products,
although no textural changes were observed by the sensory panel. Nevertheless, low-salt sausages were
clearly preferred by panellists
- …
