69 research outputs found
Long-term follow-up observations of extreme coronal line emitting galaxies
We present new spectroscopic and photometric follow-up observations of the
known sample of extreme coronal line emitting galaxies (ECLEs) identified in
the Sloan Digital Sky Survey (SDSS). With these new data, observations of the
ECLE sample now span a period of two decades following their initial SDSS
detections. We confirm the nonrecurrence of the iron coronal line signatures in
five of the seven objects, further supporting their identification as the
transient light echoes of tidal disruption events (TDEs). Photometric
observations of these objects in optical bands show little overall evolution.
In contrast, mid-infrared (MIR) observations show ongoing long-term declines.
The remaining two objects had been classified as active galactic nuclei (AGN)
with unusually strong coronal lines rather than being TDE related, given the
persistence of the coronal lines in earlier follow-up spectra. We confirm this
classification, with our spectra continuing to show the presence of strong,
unchanged coronal-line features and AGN-like MIR colours and behaviour. We have
constructed spectral templates of both subtypes of ECLE to aid in
distinguishing the likely origin of newly discovered ECLEs. We highlight the
need for higher cadence, and more rapid, follow-up observations of such objects
to better constrain their properties and evolution. We also discuss the
relationships between ECLEs, TDEs, and other identified transients having
significant MIR variability.Comment: Submitted to MNRAS. 33 pages, 15 figure
Loss of expression of TGF-βs and their receptors in chronic skin lesions induced by sulfur mustard as compared with chronic contact dermatitis patients
<p>Abstract</p> <p>Background</p> <p>Sulfur mustard (SM) is a blister-forming agent that has been used as a chemical weapon. Sulfur mustard can cause damage in various organs, especially the skin, respiratory system, and eyes. Generally, the multiple complications of mustard gas result from its alkalizing potency; it reacts with cellular components like DNA, RNA, proteins, and lipid membranes.</p> <p>TGF-β is a multi-functional cytokine with multiple biological effects ranging from cell differentiation and growth inhibition to extracellular matrix stimulation, immunosuppression, and immunomodulation. TGF-β has 3 isoforms (TGF-β 1, 2, 3) and its signaling is mediated by its receptors: R1, R2 and intracellular Smads molecules.</p> <p>TGF-β has been shown to have anti-inflammatory effects. TGF-βs and their receptors also have an important role in modulation of skin inflammation, proliferation of epidermal cells, and wound healing, and they have been implicated in different types of skin inflammatory disorders.</p> <p>Methods</p> <p>Seventeen exposed SM individuals (48.47 ± 9.3 years), 17 chronic dermatitis patients (46.52 ± 14.6 years), and 5 normal controls (44.00 ± 14.6 years) were enrolled in this study.</p> <p>Evaluation of TGF-βs and their receptors expressions was performed by semiquantitative RT-PCR. Only TGF1was analyzed immunohistochemically.</p> <p>Results</p> <p>Our results showed significant decreases in the expression percentages of TGF-β 1, 2 and R1, R2 in chemical victims in comparison with chronic dermatitis and normal subjects and significant decreases in the intensity of R1 and R2 expressions in chemical victims in comparison with chronic dermatitis and normal controls. (P value < 0.05)</p> <p>Conclusions</p> <p>TGF-βs and their receptors appear to have a noticeable role in chronic inflammatory skin lesions caused by sulfur mustard.</p
Radial distribution of dust, stars, gas, and star-formation rate in DustPedia face-on galaxies
Aims. The purpose of this work is the characterization of the radial distribution of dust, stars, gas, and star-formation rate (SFR) in a sub-sample of 18 face-on spiral galaxies extracted from the DustPedia sample.
Methods. This study is performed by exploiting the multi-wavelength DustPedia database, from ultraviolet (UV) to sub-millimeter bands, in addition to molecular (12CO) and atomic (Hi) gas maps and metallicity abundance information available in the literature. We fitted the surface-brightness profiles of the tracers of dust and stars, the mass surface-density profiles of dust, stars, molecular gas, and total gas, and the SFR surface-density profiles with an exponential curve and derived their scale-lengths. We also developed a method to solve for the CO-to-H2 conversion factor (αCO) per galaxy by using dust- and gas-mass profiles.
Results. Although each galaxy has its own peculiar behavior, we identified a common trend of the exponential scale-lengths versus wavelength. On average, the scale-lengths normalized to the B-band 25 mag/arcsec2 radius decrease from UV to 70 μm, from 0.4 to 0.2, and then increase back up to ~0.3 at 500 microns. The main result is that, on average, the dust-mass surface-density scale-length is about 1.8 times the stellar one derived from IRAC data and the 3.6 μm surface brightness, and close to that in the UV. We found a mild dependence of the scale-lengths on the Hubble stage T: the scale-lengths of the Herschel bands and the 3.6 μm scale-length tend to increase from earlier to later types, the scale-length at 70 μm tends to be smaller than that at longer sub-mm wavelength with ratios between longer sub-mm wavelengths and 70 μm that decrease with increasing T. The scale-length ratio of SFR and stars shows a weak increasing trend towards later types. Our αCO determinations are in the range (0.3−9) M⊙ pc-2 (K km s-1)-1, almost invariant by using a fixed dust-to-gas ratio mass (DGR) or a DGR depending on metallicity gradient
Long-term follow-up observations of extreme coronal line emitting galaxies
We present new spectroscopic and photometric follow-up observations of the known sample of extreme coronal line-emitting galaxies (ECLEs) identified in the Sloan Digital Sky Survey (SDSS). With these new data, observations of the ECLE sample now span a period of two decades following their initial SDSS detections. We confirm the non-recurrence of the iron coronal line signatures in five of the seven objects, further supporting their identification as the transient light echoes of tidal disruption events (TDEs). Photometric observations of these objects in optical bands show little overall evolution. In contrast, mid-infrared (MIR) observations show ongoing long-term declines consistent with power-law decay. The remaining two objects had been classified as active galactic nuclei (AGNs) with unusually strong coronal lines rather than being TDE related, given the persistence of the coronal lines in earlier follow-up spectra. We confirm this classification, with our spectra continuing to show the presence of strong, unchanged coronal line features and AGN-like MIR colours and behaviour. We have constructed spectral templates of both subtypes of ECLE to aid in distinguishing the likely origin of newly discovered ECLEs. We highlight the need for higher cadence, and more rapid, follow-up observations of such objects to better constrain their properties and evolution. We also discuss the relationships between ECLEs, TDEs, and other identified transients having significant MIR variability
Faint objects in motion: the new frontier of high precision astrometry
Funder: Istituto Nazionale di AstrofisicaSky survey telescopes and powerful targeted telescopes play complementary
roles in astronomy. In order to investigate the nature and characteristics of
the motions of very faint objects, a flexibly-pointed instrument capable of
high astrometric accuracy is an ideal complement to current astrometric surveys
and a unique tool for precision astrophysics. Such a space-based mission will
push the frontier of precision astrometry from evidence of Earth-mass habitable
worlds around the nearest stars, to distant Milky Way objects, and out to the
Local Group of galaxies. As we enter the era of the James Webb Space Telescope
and the new ground-based, adaptive-optics-enabled giant telescopes, by
obtaining these high precision measurements on key objects that Gaia could not
reach, a mission that focuses on high precision astrometry science can
consolidate our theoretical understanding of the local Universe, enable
extrapolation of physical processes to remote redshifts, and derive a much more
consistent picture of cosmological evolution and the likely fate of our cosmos.
Already several missions have been proposed to address the science case of
faint objects in motion using high precision astrometry missions: NEAT proposed
for the ESA M3 opportunity, micro-NEAT for the S1 opportunity, and Theia for
the M4 and M5 opportunities. Additional new mission configurations adapted with
technological innovations could be envisioned to pursue accurate measurements
of these extremely small motions. The goal of this White Paper is to address
the fundamental science questions that are at stake when we focus on the
motions of faint sky objects and to briefly review instrumentation and mission
profiles
Psycotherapy with children, the living relationship/ Moustakas
xvii,346 hal, ; ill,; 21 cm
Psycotherapy with children, the living relationship/ Moustakas
xvii,346 hal, ; ill, ; 21 cm
Psycotherapy with children, the living relationship/ Moustakas
xvii, 346 hal, ; ill,; 21 cm
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