177 research outputs found
Between data providers and concerned citizens: Exploring participation in precision public health in Switzerland.
This empirical article explores the dynamics of exchange and reciprocity between cohorters, that is, study organizers, and cohortees, that is, study participants. Drawing on literature on bioeconomy and valuation, we analyze cohortees' expectations in return for the "clinical labor" they perform in the pilot phase of a Swiss precision public health study. Based on an ethnography of this cohort and data from seven focus groups with cohortees (n = 37), we identified four positions: (1) the good citizen participant, (2) the critical participant, (3) the concerned participant, and (4) the self-oriented participant. These reveal that cohortees' participation, still framed in altruistic terms, nevertheless engages expectations about reciprocal obligations of the state and science in terms of public health, confirming the deep entanglement of gift-based, financial, and moral economies of participation. The different values emerging from these expectations-robust scientific evidence about environmental exposure and a socially oriented public health-provide rich indications about stake making which might matter for the future of precision public health
IGR J08408--4503: a new recurrent Supergiant Fast X-ray Transient
The supergiant fast X-ray transient IGR J08408-4503 was discovered by
INTEGRAL on May 15, 2006, during a bright flare. The source shows sporadic
recurrent short bright flares, reaching a peak luminosity of 10^36 erg s^-1
within less than one hour. The companion star is HD 74194, an Ob5Ib(f)
supergiant star located at 3 kpc in the Vela region. We report the light curves
and broad-band spectra (0.1-200 keV) of all the three flares of IGR J08408-4503
detected up to now based on INTEGRAL and Swift data. The flare spectra are well
described by a power-law model with a high energy cut-off at ~15 keV. The
absorption column density during the flares was found to be ~10^21 cm^-2,
indicating a very low matter density around the compact object. Using the
supergiant donor star parameters, the wind accretion conditions imply an
orbital period of the order of one year, a spin period of the order of hours
and a magnetic field of the order of 10^13 G.Comment: 5 pages, 2 figures, accepted for publication in Astrophysical Journal
Letter
Exceptional flaring activity of the anomalous X-ray pulsar 1E 1547.0-5408
(Abridged) We studied an exceptional period of activity of the anomalous
X-ray pulsar 1E 1547.0-5408 in January 2009, during which about 200 bursts were
detected by INTEGRAL. The major activity episode happened when the source was
outside the field of view of all the INTEGRAL instruments. But we were still
able to study the properties of 84 bursts detected simultaneously by the
anti-coincidence shield of the spectrometer SPI and by the detector of the
imager ISGRI. We find that the luminosity of the 22 January 2009 bursts of 1E
1547.0-5408 was > 1e42 erg/s. This luminosity is comparable to that of the
bursts of soft gamma repeaters (SGR) and is at least two orders of magnitude
larger than the luminosity of the previously reported bursts from AXPs.
Similarly to the SGR bursts, the brightest bursts of 1E 1547.0-5408 consist of
a short spike of ~100 ms duration with a hard spectrum, followed by a softer
extended tail of 1-10 s duration, which occasionally exhibits pulsations with
the source spin period of ~2 s. The observation of AXP bursts with luminosities
comparable to the one of SGR bursts strengthens the conjecture that AXPs and
SGRs are different representatives of one and the same source type.Comment: 9 pages, 10 figures, accepted to Astronomy & Astrophysic
The role of polysaccharide intercellular adhesin (PIA) in Staphylococcus epidermidis adhesion to host tissues and subsequent antibiotic tolerance
The aim of this study was to determine the role of polysaccharide intercellular adhesin (PIA) in Staphylococcus epidermidis adhesion to host tissues and subsequent antibiotic tolerance. The adherence of S. epidermidis 1457 and the mutant defective in PIA production (1457-M10) to urinary epithelium and endothelium was estimated by colony counting. Minimum bactericidal concentration and mean reduction of cellular activity (XTT) following antibiotic exposure was determined for planktonic and adhered bacteria. S. epidermidis 1457 adhered to a greater extent to both cells than the mutant strain. The adhered strains had a significantly higher antimicrobial tolerance than their planktonic counterparts. The mutant strain was, in general, the most susceptible to the antibiotics assayed. In conclusion, PIA may influence S. epidermidis adherence to host tissues and their antimicrobial susceptibility. Initial adhesion may be the main step for the acquisition of resistance in S. epidermidis
Quasi-Periodic Pulsations in Solar Flares: new clues from the Fermi Gamma-Ray Burst Monitor
In the last four decades it has been observed that solar flares show
quasi-periodic pulsations (QPPs) from the lowest, i.e. radio, to the highest,
i.e. gamma-ray, part of the electromagnetic spectrum. To this day, it is still
unclear which mechanism creates such QPPs. In this paper, we analyze four
bright solar flares which show compelling signatures of quasi-periodic behavior
and were observed with the Gamma-Ray Burst Monitor (\gbm) onboard the Fermi
satellite. Because GBM covers over 3 decades in energy (8 keV to 40 MeV) it can
be a key instrument to understand the physical processes which drive solar
flares. We tested for periodicity in the time series of the solar flares
observed by GBM by applying a classical periodogram analysis. However, contrary
to previous authors, we did not detrend the raw light curve before creating the
power spectral density spectrum (PSD). To assess the significance of the
frequencies we made use of a method which is commonly applied for X-ray
binaries and Seyfert galaxies. This technique takes into account the underlying
continuum of the PSD which for all of these sources has a P(f) ~ f^{-\alpha}
dependence and is typically labeled red-noise. We checked the reliability of
this technique by applying it to a solar flare which was observed by the Reuven
Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) which contains, besides
any potential periodicity from the Sun, a 4 s rotational period due to the
rotation of the spacecraft around its axis. While we do not find an intrinsic
solar quasi-periodic pulsation we do reproduce the instrumental periodicity.
Moreover, with the method adopted here, we do not detect significant QPPs in
the four bright solar flares observed by GBM. We stress that for the purpose of
such kind of analyses it is of uttermost importance to appropriately account
for the red-noise component in the PSD of these astrophysical sources.Comment: accepted by A&
Checklists for Applicants submitting dossiers on Cosmetic Ingredients to be evaluated by the SCCS
Checklists for Applicants submitting dossiers on Cosmetic Ingredients to be evaluated by the SCCSThe SCCS adopted these Checklists on 07 March 2017Checklists for Applicants submitting dossiers on Cosmetic Ingredients to be evaluated by the SCCSThe SCCS adopted these Checklists on 07 March 201
Strong bursts from the anomalous X-ray pulsar 1E 1547.0-5408 observed with the INTEGRAL/SPI Anti-Coincidence Shield
In January 2009, multiple short bursts of soft gamma-rays were detected from
the direction of the anomalous X-ray pulsar 1E 1547.0-5408 by different
satellites. Here we report on the observations obtained with the INTEGRAL
SPI-ACS detector during the period with the strongest bursting activity. More
than 200 bursts were detected at energies above 80 keV in a few hours on
January 22. Among these, two remarkably bright events showed pulsating tails
lasting several seconds and modulated at the 2.1 s spin period of 1E
1547.0-5408. The energy released in the brightest of these bursts was of a few
10^43 erg, for an assumed distance of 10 kpc. This is smaller than that of the
three giant flares seen from soft gamma-ray repeaters, but higher than that of
typical bursts from soft gamma-ray repeaters and anomalous X-ray pulsars.Comment: Accepted for publication on The Astrophysical Journal Letter
Lattice dependence of saturated ferromagnetism in the Hubbard model
We investigate the instability of the saturated ferromagnetic ground state
(Nagaoka state) in the Hubbard model on various lattices in dimensions d=2 and
d=3. A variational resolvent approach is developed for the Nagaoka instability
both for U = infinity and for U < infinity which can easily be evaluated in the
thermodynamic limit on all common lattices. Our results significantly improve
former variational bounds for a possible Nagaoka regime in the ground state
phase diagram of the Hubbard model. We show that a pronounced particle-hole
asymmetry in the density of states and a diverging density of states at the
lower band edge are the most important features in order to stabilize Nagaoka
ferromagnetism, particularly in the low density limit.Comment: Revtex, 18 pages with 18 figures, 7 pages appendices, section on bcc
lattice adde
Out of the darkness: the infrared afterglow of the INTEGRAL burst GRB 040422 observed with the VLT
GRB 040422 was detected by the INTEGRAL satellite at an angle of only 3
degrees from the Galactic plane. Analysis of the prompt emission observed with
the SPI and IBIS instruments on INTEGRAL are presented. The IBIS spectrum is
well fit by the Band model with a break energy of Eo=56+/-2 keV and
Epeak=41+/-3 keV. The peak flux is 1.8 10^(-7) erg/cm2/s and fluence 3.4
10^(-7) erg/cm2 in the range 20-200 keV. We then present the observations of
the afterglow of GRB 040422, obtained with the ISAAC and FORS 2 instruments at
the VLT less than 2 hours after the burst. We report the discovery of its
near-infrared afterglow, for which we give here the astrometry and photometry.
No detection could have been obtained in the R and I bands, partly due to the
large extinction in the Milky Way. We re-imaged the position of the afterglow
two months later in the Ks band, and detected a likely bright host galaxy. We
compare the magnitude of the afterglow with a those of a compilation of
promptly observed counterparts of previous GRBs, and show that the afterglow of
GRB 040422 lies at the very faint end of the distribution, brighter only than
that of GRB 021211, singled out later and in the optical bands, and GRB 040924
after accounting for Milky Way extinction. This observation suggests that the
proportion of dark GRBs can be significantly lowered by a more systematic use
of 8-m class telescopes in the infrared in the very early hours after the
burst.Comment: 9 pages, 7 figures, accepted in A&
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