Atmospheric fluctuations below 0.1 Hz during drift-scan solar diameter measurements

Measurements of the power spectrum of the seeing in the range 0.001-1 Hz have been performed in order to understand the criticity of the transits' method for solar diameter monitoring.Comment: 3 pages, 3 figures, proc. of the Fourth French-Chinese meeting on Solar Physics Understanding Solar Activity: Advances and Challenges, 15 - 18 November, 2011 Nice, Franc

Anomalous circular polarization profiles in the He I 1083.0 nm multiplet from solar spicules

We report Stokes vector observations of solar spicules and a prominence in the He I 1083 nm multiplet carried out with the Tenerife Infrared Polarimeter. The observations show linear polarization profiles that are produced by scattering processes in the presence of a magnetic field. After a careful data reduction, we demonstrate the existence of extremely asymmetric Stokes V profiles in the spicular material that we are able to model with two magnetic components along the line of sight, and under the presence of atomic orientation in the energy levels that give rise to the multiplet. We discuss some possible scenarios that can generate the atomic orientation in spicules. We stress the importance of spectropolarimetric observations across the limb to distinguish such signals from observational artifacts.Comment: accepted for publication in Ap

Molecular characterization of genes involved in chicken MHC class I antigen presentation pathway

Tapasin, TAP1 and TAP2 are involved in the assembly of MHC class I molecules. The genes encoding these three products belong to the Major Histocompatibility Complex: in chicken, Tapasin is located between the two class IIb genes, while TAP1 and TAP2 are found between the two class I genes. The current study aimed at the molecular characterization of these three genes. Starting from Single Nucleotide Polymorphisms (11 in Tapasin, 18 in TAP1 and 21 in TAP2) previously discovered by the authors within these genes, the nucleotide diversity was assessed at each locus. Moreover, the haplotypes were reconstructed for each individual and the genetic distances between the chicken lines and breeds were estimated. From the analysis of the nucleotide diversity values, variable polymorphism rates could be observed among the three genes. In the three analyzed loci the SNPs rates were higher than the reported chicken genome mean nucleotide diversity of 5 SNPs kb-1. The calculation of the genetic distances permitted, generally, the distinction of animals among the analyzed lines/breeds

Characterization of a thinned back illuminated MIMOSA V sensor as a visible light camera

Abstract This paper reports the measurements that have been performed both in the Silicon Detector Laboratory at the University of Insubria (Como, Italy) and at the Instituto Ricerche SOlari Locarno (IRSOL) to characterize a CMOS pixel particle detector as a visible light camera. The CMOS sensor has been studied in terms of Quantum Efficiency in the visible spectrum, image blooming and reset inefficiency in saturation condition. The main goal of these measurements is to prove that this kind of particle detector can also be used as an ultra fast, 100% fill factor visible light camera in solar physics experiments

Systemic thromboembolism from a misdiagnosed non-bacterial thrombotic endocarditis in a patient with lung cancer: A case report

Thromboembolic events are frequent in patients with cancer, commonly involving the venous and pulmonary circulation. The arterial system is rarely implicated in embolism and, when involved, a cardiogenic origin should always be excluded. In the present study, a case of a patient who developed multiple embolic events concomitantly with the diagnosis of locally-advanced non-small cell lung cancer with high expression levels of programmed death-ligand 1 (PD-L1) in >50% of tumor cells is reported. A cardiac defect interpreted as a patent foramen ovale required low molecular weight heparin administration. Despite the anti-coagulant therapy, before first-line anticancer treatment with pembrolizumab immunotherapy could be administered due to high PD-L1 expression levels, a new hospitalization was required due to the onset of novel ischemic manifestation. New transthoracic and transesophageal echocardiography revealed a previously misdiagnosed vegetation of the mitral valve that caused systemic embolization. The lack of any sign of infection led to the diagnosis of a non-bacterial thrombotic endocarditis (NBTE), whose embolic sprouting gave rise to the widespread ischemic events. No active anticancer treatment was feasible due to the rapid progression of the disease. NBTE can evolve quickly, eventually preventing any chance of treatment targeting the primary cause, which in the present study was lung cancer. If NBTE can be correctly diagnosed sooner then there may be the potential for anticancer therapy that does not worsen the hypercoagulability state, thus improving cancer-associated survival

Heterogeneous ice nucleation on dust particles sourced from nine deserts worldwide - Part 1: Immersion freezing

Desert dust is one of the most abundant ice nucleating particle types in the atmosphere. Traditionally, clay minerals were assumed to determine the ice nucleation ability of desert dust and constituted the focus of ice nucleation studies over several decades. Recently some feldspar species were identified to be ice active at much higher temperatures than clay minerals, redirecting studies to investigate the contribution of feldspar to ice nucleation on desert dust. However, so far no study has shown the atmospheric relevance of this mineral phase. For this study four dust samples were collected after airborne transport in the troposphere from the Sahara to different locations (Crete, the Peloponnese, Canary Islands, and the Sinai Peninsula). Additionally, 11 dust samples were collected from the surface from nine of the biggest deserts worldwide. The samples were used to study the ice nucleation behavior specific to different desert dusts. Furthermore, we investigated how representative surface-collected dust is for the atmosphere by comparing to the ice nucleation activity of the airborne samples. We used the IMCA-ZINC setup to form droplets on single aerosol particles which were subsequently exposed to temperatures between 233 and 250 K. Dust particles were collected in parallel on filters for offline cold-stage ice nucleation experiments at 253–263 K. To help the interpretation of the ice nucleation experiments the mineralogical composition of the dusts was investigated. We find that a higher ice nucleation activity in a given sample at 253 K can be attributed to the K-feldspar content present in this sample, whereas at temperatures between 238 and 245 K it is attributed to the sum of feldspar and quartz content present. A high clay content, in contrast, is associated with lower ice nucleation activity. This confirms the importance of feldspar above 250 K and the role of quartz and feldspars determining the ice nucleation activities at lower temperatures as found by earlier studies for monomineral dusts. The airborne samples show on average a lower ice nucleation activity than the surface-collected ones. Furthermore, we find that under certain conditions milling can lead to a decrease in the ice nucleation ability of polymineral samples due to the different hardness and cleavage of individual mineral phases causing an increase of minerals with low ice nucleation ability in the atmospherically relevant size fraction. Comparison of our data set to an existing desert dust parameterization confirms its applicability for climate models. Our results suggest that for an improved prediction of the ice nucleation ability of desert dust in the atmosphere, the modeling of emission and atmospheric transport of the feldspar and quartz mineral phases would be key, while other minerals are only of minor importance

Understanding the History of Two Complex Ice Crystal Habits Deduced From a Holographic Imager

The sizes and shapes of ice crystals influence the radiative properties of clouds, as well as precipitation initiation and aerosol scavenging. However, ice crystal growth mechanisms remain only partially characterized. We present the growth processes of two complex ice crystal habits observed in Arctic mixed-phase clouds during the Ny-Ålesund AeroSol Cloud ExperimeNT campaign. First, are capped-columns with multiple columns growing out of the plates' corners that we define as columns on capped-columns. These ice crystals originated from cycling through the columnar and plate temperature growth regimes, during their vertical transport by in-cloud circulation. Second, is aged rime on the surface of ice crystals having grown into faceted columns or plates depending on the environmental conditions. Despite their complexity, the shapes of these ice crystals allow to infer their growth history and provide information about the in-cloud conditions. Additionally, these ice crystals exhibit complex shapes and could enhance aggregation and secondary ice production

NLTE modeling of Stokes vector center-to-limb variations in the CN violet system

The solar surface magnetic field is connected with and even controls most of the solar activity phenomena. Zeeman effect diagnostics allow for measuring only a small fraction of the fractal-like structured magnetic field. The remaining hidden magnetic fields can only be accessed with the Hanle effect. Molecular lines are very convenient for applying the Hanle effect diagnostics thanks to the broad range of magnetic sensitivities in a narrow spectral region. With the UV version of the Zurich Imaging Polarimeter ZIMPOL II installed at the 45 cm telescope of the Istituto Ricerche Solari Locarno (IRSOL), we simultaneously observed intensity and linear polarization center-to-limb variations in two spectral regions containing the (0,0) and (1,1) bandheads of the CN B 2 {\Sigma} - X 2 {\Sigma} system. Here we present an analysis of these observations. We have implemented coherent scattering in molecular lines into a NLTE radiative transfer code. A two-step approach was used. First, we separately solved the statistical equilibrium equations and compute opacities and intensity while neglecting polariza- tion. Then we used these quantities as input for calculating scattering polarization and the Hanle effect. We have found that it is impossible to fit the intensity and polarization simultaneously at different limb angles in the frame- work of standard 1D modeling. The atmosphere models that provide correct intensity center-to-limb variations fail to fit linear polar- ization center-to-limb variations due to lacking radiation field anisotropy. We had to increase the anisotropy by means of a specially introduced free parameter. This allows us to successfully interpret our observations. We discuss possible reasons for underestimating the anisotropy in the 1D modeling.Comment: 15 pages, 10 figures, accepted for publication in Astronomy&Astrophysic

First polarimetric measurements and modeling of the Paschen-Back effect in CaH transitions

We report the first spectropolarimetric observations and modeling of CaH transitions in sunspots. We have detected strong polarization signals in many CaH lines from the A-X system, and we provide the first successful fit to the observed Stokes profiles using the previously developed theory of the Paschen-Back effect in arbitrary electronic states of diatomic molecules and polarized radiative transfer in molecular lines in stellar atmospheres. We analyze the CaH Stokes profiles together with quasi-simultaneous observations in TiO bands and conclude that CaH provides a valuable diagnostic of magnetic fields in sunspots, starspots, cool stars, and brown dwarfs