426 research outputs found
The ArT\'eMiS wide-field submillimeter camera: preliminary on-sky performances at 350 microns
ArTeMiS is a wide-field submillimeter camera operating at three wavelengths
simultaneously (200, 350 and 450 microns). A preliminary version of the
instrument equipped with the 350 microns focal plane, has been successfully
installed and tested on APEX telescope in Chile during the 2013 and 2014
austral winters. This instrument is developed by CEA (Saclay and Grenoble,
France), IAS (France) and University of Manchester (UK) in collaboration with
ESO. We introduce the mechanical and optical design, as well as the cryogenics
and electronics of the ArTeMiS camera. ArTeMiS detectors are similar to the
ones developed for the Herschel PACS photometer but they are adapted to the
high optical load encountered at APEX site. Ultimately, ArTeMiS will contain 4
sub-arrays at 200 microns and 2x8 sub-arrays at 350 and 450 microns. We show
preliminary lab measurements like the responsivity of the instrument to hot and
cold loads illumination and NEP calculation. Details on the on-sky
commissioning runs made in 2013 and 2014 at APEX are shown. We used planets
(Mars, Saturn, Uranus) to determine the flat-field and to get the flux
calibration. A pointing model was established in the first days of the runs.
The average relative pointing accuracy is 3 arcsec. The beam at 350 microns has
been estimated to be 8.5 arcsec, which is in good agreement with the beam of
the 12 m APEX dish. Several observing modes have been tested, like On-The-Fly
for beam-maps or large maps, spirals or raster of spirals for compact sources.
With this preliminary version of ArTeMiS, we concluded that the mapping speed
is already more than 5 times better than the previous 350 microns instrument at
APEX. The median NEFD at 350 microns is 600 mJy.s1/2, with best values at 300
mJy.s1/2. The complete instrument with 5760 pixels and optimized settings will
be installed during the first half of 2015.Comment: 11 pages, 11 figures. Presented at SPIE Millimeter, Submillimeter,
and Far-Infrared Detectors and Instrumentation for Astronomy VII, June 24,
2014. To be published in Proceedings of SPIE Volume 915
A Multiwavelength Study of a Sample of 70 micron Selected Galaxies in the COSMOS Field I: Spectral Energy Distributions and Luminosities
We present a large robust sample of 1503 reliable and unconfused 70microm
selected sources from the multiwavelength data set of the Cosmic Evolution
Survey (COSMOS). Using the Spitzer IRAC and MIPS photometry, we estimate the
total infrared luminosity, L_IR (8--1000 microns), by finding the best fit
template from several different template libraries. The long wavelength 70 and
160 micron data allow us to obtain a reliable estimate of L_IR, accurate to
within 0.2 and 0.05 dex, respectively. The 70 micron data point enables a
significant improvement over the luminosity estimates possible with only a 24
micron detection. The full sample spans a wide range in L_IR, L_IR ~ 10^8-10^14
L_sun, with a median luminosity of 10^11.4 L_sun. We identify a total of 687
luminous, 303 ultraluminous, and 31 hyperluminous infrared galaxies (LIRGs,
ULIRGs, and HyLIRGs) over the redshift range 0.01<z<3.5 with a median redshift
of 0.5. Presented here are the full spectral energy distributions for each of
the sources compiled from the extensive multiwavelength data set from the
ultraviolet (UV) to the far-infrared (FIR). Using SED fits we find possible
evidence for a subset of cooler ultraluminous objects than observed locally.
However, until direct observations at longer wavelengths are obtained, the peak
of emission and the dust temperature cannot be well constrained. We use these
SEDs, along with the deep radio and X-ray coverage of the field, to identify a
large sample of candidate active galactic nuclei (AGN). We find that the
fraction of AGN increases strongly with L_IR, as it does in the local universe,
and that nearly 70% of ULIRGs and all HyLIRGs likely host a powerful AGN.Comment: 31 pages including 31 figures and 6 tables. Accepted for publication
in ApJ. The full resolution version is available here:
http://www.ifa.hawaii.edu/~jeyhan/paperI/Kartaltepe_70mic_PaperI.pd
Near-Infrared Photometry of Carbon Stars
Near-infrared, JHKL, photometry of 239 Galactic carbon-rich variable stars is
presented and discussed. From these and published data the stars were
classified as Mira or non-Mira variables and amplitudes and pulsation periods,
ranging from 222 to 948 days for the Miras, were determined for most of them. A
comparison of the colour and period relations with those of similar stars in
the Large Magellanic Cloud indicates minor differences, which may be the
consequence of sample selection effects. Apparent bolometric magnitudes were
determined by combining the mean JHKL fluxes with mid-infrared photometry from
IRAS and MSX. Then, using the Mira period luminosity relation to set the
absolute magnitudes, distances were determined -- to greater accuracy than has
hitherto been possible for this type of star. Bolometric corrections to the K
magnitude were calculated and prescriptions derived for calculating these from
various colours. Mass-loss rates were also calculated and compared to values in
the literature.
Approximately one third of the C-rich Miras and an unknown fraction of the
non-Miras exhibit apparently random obscuration events that are reminiscent of
the phenomena exhibited by the hydrogen deficient RCB stars. The underlying
cause of this is unclear, but it may be that mass loss, and consequently dust
formation, is very easily triggered from these very extended atmospheres.Comment: 35 pages, 21 figs, accepted for publication in MNRAS. Large data
table will be available on-line onl
Planck intermediate results. VIII. Filaments between interacting clusters
About half of the baryons of the Universe are expected to be in the form of
filaments of hot and low density intergalactic medium. Most of these baryons
remain undetected even by the most advanced X-ray observatories which are
limited in sensitivity to the diffuse low density medium. The Planck satellite
has provided hundreds of detections of the hot gas in clusters of galaxies via
the thermal Sunyaev-Zel'dovich (tSZ) effect and is an ideal instrument for
studying extended low density media through the tSZ effect. In this paper we
use the Planck data to search for signatures of a fraction of these missing
baryons between pairs of galaxy clusters. Cluster pairs are good candidates for
searching for the hotter and denser phase of the intergalactic medium (which is
more easily observed through the SZ effect). Using an X-ray catalogue of
clusters and the Planck data, we select physical pairs of clusters as
candidates. Using the Planck data we construct a local map of the tSZ effect
centered on each pair of galaxy clusters. ROSAT data is used to construct X-ray
maps of these pairs. After having modelled and subtracted the tSZ effect and
X-ray emission for each cluster in the pair we study the residuals on both the
SZ and X-ray maps. For the merging cluster pair A399-A401 we observe a
significant tSZ effect signal in the intercluster region beyond the virial
radii of the clusters. A joint X-ray SZ analysis allows us to constrain the
temperature and density of this intercluster medium. We obtain a temperature of
kT = 7.1 +- 0.9, keV (consistent with previous estimates) and a baryon density
of (3.7 +- 0.2)x10^-4, cm^-3. The Planck satellite mission has provided the
first SZ detection of the hot and diffuse intercluster gas.Comment: Accepted by A&
Hyperexcitability of the local cortical circuit in mouse models of tuberous sclerosis complex
Tuberous sclerosis complex (TSC) is a neurogenetic disorder associated with epilepsy, intellectual disabilities, and autistic behaviors. These neurological symptoms result from synaptic dysregulations, which shift a balance between excitation and inhibition. To decipher the synaptic substrate of hyperexcitability, we examined pan-neuronal Tsc1 knockout mouse and found a reduction in surface expression of a GABA receptor (GABAR) subunit but not AMPA receptor (AMPAR) subunit. Using electrophysiological recordings, we found a significant reduction in the frequency of GABAR-mediated miniature inhibitory postsynaptic currents (GABAR-mIPSCs) but not AMPAR-mediated miniature excitatory postsynaptic currents (AMPAR-mEPSCs) in layer 2/3 pyramidal neurons. To determine a subpopulation of interneurons that are especially vulnerable to the absence of TSC1 function, we also analyzed two strains of conditional knockout mice targeting two of the prominent interneuron subtypes that express parvalbumin (PV) or somatostatin (SST). Unlike pan-neuronal knockout mice, both interneuron-specific Tsc-1 knockout mice did not develop spontaneous seizures and grew into adults. Further, the properties of AMPAR-mEPSCs and GABAR-mIPSCs were normal in both Pv-Cre and Sst-Cre x Tsc1fl/fl knockout mice. These results indicate that removal of TSC1 from all neurons in a local cortical circuit results in hyperexcitability while connections between pyramidal neurons and interneurons expressing PV and SST are preserved in the layer 2/3 visual cortex. Our study suggests that another inhibitory cell type or a combination of multiple subtypes may be accountable for hyperexcitability in TSC. Keywords: Tuberous sclerosis complex; E/I balance; AMPA receptor; GABA receptor; Autism; Epilepsy; mTOR pathwa
Planck 2013 results. VI. High Frequency Instrument data processing
We describe the processing of the 531 billion raw data samples from the High Frequency Instrument (hereafter HFI), which we performed to produce six temperature maps from the first 473 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143, 217, 353, 545, and 857 GHz with an angular resolution ranging from 9.7 to 4.6 arcmin. The detector noise per (effective) beam solid angle is respectively, 10, 6, 12 and 39 microKelvin in HFI four lowest frequency channel (100--353 GHz) and 13 and 14 kJy/sr for the 545 and 857 GHz channels. Using the 143 GHz channel as a reference, these two high frequency channels are intercalibrated within 5% and the 353 GHz relative calibration is at the percent level. The 100 and 217 GHz channels, which together with the 143 GHz channel determine the high-multipole part of the CMB power spectrum (50 < l <2500), are intercalibrated at better than 0.2 %
Efficacy and Safety of Dupilumab in the Treatment of Hand Eczema: A Retrospective Study
Background: Hand eczema (HE) is a prevalent chronic condition that exerts a substantial and enduring adverse effect on quality of life (QoL) and imposes an economic burden on society. Managing HE poses challenges due to the limited effectiveness and potential adverse effects associated with many currently available topical and systemic treatments. Methods: This article examines twenty-one patients affected by HE treated with dupilumab, a fully human monoclonal antibody targeting interleukin IL-4 and IL-13 signaling. This involves a retrospective descriptive statistical analysis. Results: At week 6, HECSI-75 was achieved by 12 patients (57.9%). The proportion of patients meeting the HECSI-75 criteria steadily increased over the observation weeks, reaching 90% at week 16 and 100% at week 104. Furthermore, HECSI-90 and HECSI-100 were achieved by 75% and 60% of patients at week 16 and by 100% and 85% of patients at week 68, respectively. All patients who reached week 104 maintained complete disease remission according to HECSI 100. Conclusions: In all patients, dupilumab was shown to be an effective drug in achieving disease clearance, as indicated by all the parameters considered at each evaluation point (Week 6, Week 16, Week 32, Week 52, Week 68, Week 84, and Week 104), in comparison to the initial baseline
Why Are Outcomes Different for Registry Patients Enrolled Prospectively and Retrospectively? Insights from the Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF).
Background: Retrospective and prospective observational studies are designed to reflect real-world evidence on clinical practice, but can yield conflicting results. The GARFIELD-AF Registry includes both methods of enrolment and allows analysis of differences in patient characteristics and outcomes that may result. Methods and Results: Patients with atrial fibrillation (AF) and ≥1 risk factor for stroke at diagnosis of AF were recruited either retrospectively (n = 5069) or prospectively (n = 5501) from 19 countries and then followed prospectively. The retrospectively enrolled cohort comprised patients with established AF (for a least 6, and up to 24 months before enrolment), who were identified retrospectively (and baseline and partial follow-up data were collected from the emedical records) and then followed prospectively between 0-18 months (such that the total time of follow-up was 24 months; data collection Dec-2009 and Oct-2010). In the prospectively enrolled cohort, patients with newly diagnosed AF (≤6 weeks after diagnosis) were recruited between Mar-2010 and Oct-2011 and were followed for 24 months after enrolment. Differences between the cohorts were observed in clinical characteristics, including type of AF, stroke prevention strategies, and event rates. More patients in the retrospectively identified cohort received vitamin K antagonists (62.1% vs. 53.2%) and fewer received non-vitamin K oral anticoagulants (1.8% vs . 4.2%). All-cause mortality rates per 100 person-years during the prospective follow-up (starting the first study visit up to 1 year) were significantly lower in the retrospective than prospectively identified cohort (3.04 [95% CI 2.51 to 3.67] vs . 4.05 [95% CI 3.53 to 4.63]; p = 0.016). Conclusions: Interpretations of data from registries that aim to evaluate the characteristics and outcomes of patients with AF must take account of differences in registry design and the impact of recall bias and survivorship bias that is incurred with retrospective enrolment. Clinical Trial Registration: - URL: http://www.clinicaltrials.gov . Unique identifier for GARFIELD-AF (NCT01090362)
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