709 research outputs found

    Ocular Refraction at Birth and Its Development During the First Year of Life in a Large Cohort of Babies in a Single Center in Northern Italy

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    The purpose of this study was to investigate refraction at birth and during the first year of life in a large cohort of babies born in a single center in Northern Italy. We also aimed to analyze refractive errors in relation to the gestational age at birth. An observational ophthalmological assessment was performed within 24 h of birth on 12,427 newborns. Refraction was examined using streak retinoscopy after the administration of tropicamide (1%). Values in the range of between +0.50 ≀ D ≀ +4.00 were defined as physiological refraction at birth. Newborns with refraction values outside of the physiological range were followed up during the first year of life. Comparative analyses were conducted in a subgroup of babies with known gestational ages. The following distribution of refraction at birth was recorded: 88.03% of the babies had physiological refraction, 5.03% had moderate hyperopia, 2.14% had severe hyperopia, 3.4%, had emmetropia, 0.45%, had myopia, 0.94% had astigmatism, and 0.01% had anisometropia. By the end of the first year of life, we observed reductions in hyperopia and astigmatism, and stabilization of myopia. Preterm babies had a four-fold higher risk of congenital myopia and a three-fold higher risk of congenital emmetropia as compared to term babies. Refraction profiles obtained at birth changed during the first year of life, leading to a normalization of the refraction values. Gestational age at birth affected the incidence of refractive errors and amblyopia

    A survey of HC_3N in extragalactic sources: Is HC_3N a tracer of activity in ULIRGs?

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    Context. HC_3N is a molecule that is mainly associated with Galactic star-forming regions, but it has also been detected in extragalactic environments. Aims. To present the first extragalactic survey of HC_3N, when combining earlier data from the literature with six new single-dish detections, and to compare HC_3N with other molecular tracers (HCN, HNC), as well as other properties (silicate absorption strength, IR flux density ratios, C_(II) flux, and megamaser activity). Methods. We present mm IRAM 30 m, OSO 20 m, and SEST observations of HC_3N rotational lines (mainly the J = 10–9 transition) and of the J = 1–0 transitions of HCN and HNC. Our combined HC_3N data account for 13 galaxies (excluding the upper limits reported for the non-detections), while we have HCN and HNC data for more than 20 galaxies. Results. A preliminary definition “HC_3N-luminous galaxy” is made based upon the HC_3N/HCN ratio. Most (~80%) HC_3N-luminous galaxies seem to be deeply obscured galaxies and (U)LIRGs. A majority (~60% or more) of the HC3N-luminous galaxies in the sample present OH mega- or strong kilomaser activity. A possible explanation is that both HC_3N and OH megamasers need warm dust for their excitation. Alternatively, the dust that excites the OH megamaser offers protection against UV destruction of HC_3N. A high silicate absorption strength is also found in several of the HC_3N-luminous objects, which may help the HC3N to survive. Finally, we find that a high HC_3N/HCN ratio is related to a high dust temperature and a low C_(II) flux

    Evidence for a chemically differentiated outflow in Mrk 231

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    Aims: Our goal is to study the chemical composition of the outflows of active galactic nuclei and starburst galaxies. Methods: We obtained high-resolution interferometric observations of HCN and HCO+^+ J=1→0J=1\rightarrow0 and J=2→1J=2\rightarrow1 of the ultraluminous infrared galaxy Mrk~231 with the IRAM Plateau de Bure Interferometer. We also use previously published observations of HCN and HCO+^+ J=1→0J=1\rightarrow0 and J=3→2J=3\rightarrow2, and HNC J=1→0J=1\rightarrow0 in the same source. Results: In the line wings of the HCN, HCO+^+, and HNC emission, we find that these three molecular species exhibit features at distinct velocities which differ between the species. The features are not consistent with emission lines of other molecular species. Through radiative transfer modelling of the HCN and HCO+^+ outflow emission we find an average abundance ratio X(HCN)/X(HCO+)≳1000X(\mathrm{HCN})/X(\mathrm{HCO}^+)\gtrsim1000. Assuming a clumpy outflow, modelling of the HCN and HCO+^+ emission produces strongly inconsistent outflow masses. Conclusions: Both the anti-correlated outflow features of HCN and HCO+^+ and the different outflow masses calculated from the radiative transfer models of the HCN and HCO+^+ emission suggest that the outflow is chemically differentiated. The separation between HCN and HCO+^+ could be an indicator of shock fronts present in the outflow, since the HCN/HCO+^+ ratio is expected to be elevated in shocked regions. Our result shows that studies of the chemistry in large-scale galactic outflows can be used to better understand the physical properties of these outflows and their effects on the interstellar medium (ISM) in the galaxy.Comment: 12 pages, 8 figures, accepted for publication in A&

    Molecular gas in the northern nucleus of Mrk273: Physical and chemical properties of the disk and its outflow

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    Aiming to characterise the properties of the molecular gas in the ultraluminous infrared galaxy Mrk273 and its outflow, we used the NOEMA interferometer to image the dense gas molecular tracers HCN, HCO+, HNC, HOC+ and HC3N at 86GHz and 256GHz with angular resolutions of 4.9x4.5 arcsec (3.7x3.4 kpc) and 0.61x0.55 arcsec (460x420 pc). We also modelled the flux of several H2O lines observed with Herschel using a radiative transfer code that includes excitation by collisions as well as by far-infrared photons. The disk of the Mrk273 north nucleus has two components with decoupled kinematics. The gas in the outer parts (1.5 kpc) rotates with a south-east to north-west direction, while in the inner disk (300 pc) follows a north-east to south-west rotation. The central 300 pc, which hosts a compact starburst region, is filled with dense and warm gas, contains a dynamical mass of (4-5)x10^9M_sun, a luminosity of L'_HCN=(3-4)x10^8 K km/s pc^2, and a dust temperature of 55 K. At the very centre, a compact core with R~50 pc has a luminosity of L_IR=4x10^11L_sun (30% of the total infrared luminosity), and a dust temperature of 95 K. The core is expanding at low velocities ~50-100 km/s, probably affected by the outflowing gas. We detect the blue-shifted component of the outflow, while the red-shifted counterpart remains undetected in our data. Its cold and dense phase reaches fast velocities up to ~1000 km/s, while the warm outflowing gas has more moderate maximum velocities of ~600 km/s. The outflow is detected as far as 460 pc from the centre in the northern direction, and has a mass of dense gas <8x10^8M_sun. The difference between the position angles of the inner disk (~70 degree) and the outflow (~10 degree) indicates that the outflow is likely powered by the AGN, and not by the starburst. Regarding the chemistry, we measure an extremely low HCO+/HOC+ ratio of 10+-5 in the inner disk of Mrk273.Comment: Accepted for publication in A&A. 21 pages, 17 figures, 7 tables, and a lot of interesting tex

    Localization of orexin B and receptor 2 for orexins in testicular cytotypes of the camelid alpaca (Vicugna pacos).

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    The orexins A (OxA) and B (OxB) are two hypothalamic peptides involved in many physiological functions of the mammalian body. They act through the binding of two G-coupled receptors named receptor 1 (OX1 ) and receptor 2 (OX2 ) for orexins. The first receptor is specific for OxA, while the second binds both the substances with equal affinity. The orexins and the relative receptors have been traced by means of different techniques also at the periphery of the body and particularly in the adrenals, and in gastrointestinal and genital organs. Aim of this work was to investigate the presence of OxB and OX2 by means of immunohistochemistry and Western blotting analysis in the testis of the South American camelid alpaca, a species primarily breed in Chile and Ecuador and recently diffused in Europe where the quality of its wool is particularly appreciated. OxB immunoreactivity (IR) was found in the tubular compartment of the testis where spermatogonia (resting), zygotene and pachytene spermatocytes, and spermatids clearly showed differently sized and shaped cytoplasmic positive structures. OX2 -IR was found both in the interstitial and tubular compartments of the testis and particularly in Leydig cells and round and elongated spermatids. Western blotting analysis of testis lysates showed the presence of a protein band whose molecular weight corresponded to that currently assigned to OX2 . Such findings easily translate the hypothesis that OxB and its receptor 2 play a functional role both in the interstitial and tubular compartments of the alpaca testis

    The Dense Molecular Gas and Nuclear Activity in the ULIRG IRAS 13120-5453

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    We present new ALMA Band 7 (∌340\sim340 GHz) observations of the dense gas tracers HCN, HCO+^+, and CS in the local, single-nucleus, ultraluminous infrared galaxy IRAS 13120-5453. We find centrally enhanced HCN (4-3) emission, relative to HCO+^+ (4-3), but do not find evidence for radiative pumping of HCN. Considering the size of the starburst (0.5 kpc) and the estimated supernovae rate of ∌1.2\sim1.2 yr−1^{-1}, the high HCN/HCO+^+ ratio can be explained by an enhanced HCN abundance as a result of mechanical heating by the supernovae, though the active galactic nucleus and winds may also contribute additional mechanical heating. The starburst size implies a high ÎŁIR\Sigma_{IR} of 4.7×10124.7\times10^{12} L⊙L_{\odot} kpc−2^{-2}, slightly below predictions of radiation-pressure limited starbursts. The HCN line profile has low-level wings, which we tentatively interpret as evidence for outflowing dense molecular gas. However, the dense molecular outflow seen in the HCN line wings is unlikely to escape the galaxy and is destined to return to the nucleus and fuel future star formation. We also present modeling of Herschel observations of the H2_2O lines and find a nuclear dust temperature of ∌40\sim40 K. IRAS 13120-5453 has a lower dust temperature and ÎŁIR\Sigma_{IR} than is inferred for the systems termed "compact obscured nuclei" (such as Arp 220 and Mrk 231). If IRAS 13120-5453 has undergone a compact obscured nucleus phase, we are likely witnessing it at a time when the feedback has already inflated the nuclear ISM and diluted star formation in the starburst/AGN core.Comment: accepted for publication in ApJ, 21 pages, 11 figure

    Central serous chorioretinopathy: Pathogenesis and management

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    Central serous chorioretinopathy (CSC) is a common retina disease and has a relative high recurrence rate, etiology, and pathogenesis of which remains largely ambiguous. The effects on the retina are usually self-limited, although some people are left with permanent vision loss due to progressive and irreversible photoreceptor damage or retinal pigment epithelium atrophy. There have been a number of interventions used in CSC, including, but not limited to, laser treatment, photodynamic therapy (PDT), intravitreal injection of anti-vascular endothelial growth factor agents, and subthreshold lasers. It is not clear whether there is a clinically important benefit to treating acute CSC, which often resolves spontaneously as part of its natural history. Of the interventions studied to date, PDT and micropulse laser treatment appear the most promising

    The influence of cosmic rays in the circumnuclear molecular gas of NGC1068

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    We surveyed the circumnuclear disk of the Seyfert galaxy NGC1068 between the frequencies 86.2 GHz and 115.6 GHz, and identified 17 different molecules. Using a time and depth dependent chemical model we reproduced the observational results, and show that the column densities of most of the species are better reproduced if the molecular gas is heavily pervaded by a high cosmic ray ionization rate of about 1000 times that of the Milky Way. We discuss how molecules in the NGC1068 nucleus may be influenced by this external radiation, as well as by UV radiation fields.Comment: 6 pages. Conference proceeding for the workshop on "Cosmic-ray induced phenomenology in star-forming environments" held in Sant Cugat, Spain, on April 16-19, 201

    Luminous, pc-scale CO 6-5 emission in the obscured nucleus of NGC1377

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    High resolution submm observations are important in probing the morphology, column density and dynamics of obscured active galactic nuclei (AGNs). With high resolution (0.06 x 0.05) ALMA 690 GHz observations we have found bright (TB >80 K) and compact (FWHM 10x7 pc) CO 6-5 line emission in the nucleus of the extremely radio-quiet galaxy NGC1377. The integrated CO 6-5 intensity is aligned with the previously discovered jet/outflow of NGC1377 and is tracing the dense (n>1e4 cm-3), hot gas at the base of the outflow. The velocity structure is complex and shifts across the jet/outflow are discussed in terms of jet-rotation or separate, overlapping kinematical components. High velocity gas (deltaV +-145 km/s) is detected inside r<2-3 pc and we suggest that it is emerging from an inclined rotating disk or torus of position angle PA=140+-20 deg with a dynamical mass of approx 3e6 Msun. This mass is consistent with that of a supermassive black hole (SMBH), as inferred from the M-sigma relation. The gas mass of the proposed disk/torus constitutes <3% of the nuclear dynamical mass. In contrast to the intense CO 6-5 line emission, we do not detect dust continuum with an upper limit of S(690GHz)<2mJy. The corresponding, 5 pc, H2 column density is estimated to N(H2)<3e23 cm-2, which is inconsistent with a Compton Thick (CT) source. We discuss the possibility that CT obscuration may be occuring on small (subparsec) or larger scales. From SED fitting we suggest that half of the IR emission of NGC1377 is nuclear and the rest (mostly the far-infrared (FIR)) is more extended. The extreme radio quietness, and the lack of emission from other star formation tracers, raise questions on the origin of the FIR emission. We discuss the possibility that it is arising from the dissipation of shocks in the molecular jet/outflow or from irradiation by the nuclear source along the poles.Comment: 7 pages, 5 figures, submitted to Astronomy and Astrophysic
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