Multiline Zeeman Signatures Through Line Addition

In order to get a significant Zeeman signature in the polarised spectra of a magnetic star, we usually 'add' the contributions of numerous spectral lines; the ultimate goal is to recover the spectropolarimetric prints of the magnetic field in these line additions. Here we want to clarify the meaning of these techniques of line addition; in particular, we try to interpret the meaning of the 'pseudo-line' formed during this process and to find out why and how its Zeeman signature is still meaningful. We create a synthetic case of line addition and apply well tested standard solar methods routinely used in the research on magnetism in our nearest star. The results are convincing and the Zeeman signatures well detected; Solar methods are found to be quite efficient also for stellar observations. We statistically compare line addition with least-squares deconvolution and demonstrate that they both give very similar results as a consequence of the special statistical properties of the weights. The Zeeman signatures are unequivocally detected in this multiline approach. We may anticipate the outcome that magnetic field detection is reliable well beyond the weak-field approximation. Linear polarisation in the spectra of solar type stars can be detected when the spectral resolution is sufficiently high.Comment: 8 pages, accepted for publication in A&

Complete genome sequence of the novel phage MG-B1 infecting bacillus weihenstephanensis

Here, we describe a novel virulent bacteriophage that infects Bacillus weihenstephanensis, isolated from soil in Austria. It is the first phage to be discovered that infects this species. Here, we present the complete genome sequence of this podovirus

Stellar model atmospheres with magnetic line blanketing. III. The role of magnetic field inclination

Context. See abstract in the paper. Aims. In the last paper of this series we study the effects of the magnetic field, varying its strength and orientation, on the model atmosphere structure, the energy distribution, photometric colors and the hydrogen Balmer line profiles. We compare with the previous results for an isotropic case in order to understand whether there is a clear relation between the value of the magnetic field angle and model changes, and to study how important the additional orientational information is. Also, we examine the probable explanation of the visual flux depressions of the magnetic chemically peculiar stars in the context of this work. Methods. We calculated one more grid of the model atmospheres of magnetic A and B stars for different effective temperatures (Teff=8000K, 11000K, 15000K), magnetic field strengths (B=0, 5, 10, 40 kG) and various angles of the magnetic field (Omega=0-90 degr) with respect to the atmosphere plane. We used the LLmodels code which implements a direct method for line opacity calculation, anomalous Zeeman splitting of spectral lines, and polarized radiation transfer. Results. We have not found significant changes in model atmosphere structure, photometric and spectroscopic observables or profiles of hydrogen Balmer lines as we vary the magnetic field inclination angle Omega. The strength of the magnetic field plays the main role in magnetic line blanketing. We show that the magnetic field has a clear relation to the visual flux depressions of the magnetic CP stars. Conclusions. See abstract in the paper.Comment: 10 pages, 5 figure

Rebuilding the Cepheid Distance Scale I: A Global Analysis of Cepheid Mean Magnitudes

We develop a statistical method for using multicolor photometry to determine distances using Cepheid variables including the effects of temperature, extinction, and metallicity and apply it to UBVRIJHK photometry of 694 Cepheids in 17 galaxies. We derive homogeneous distance, extinction and uncertainty estimates for four models, starting from the standard extragalactic method and then adding the physical effects of temperature distributions, extinction distributions, requiring positive definite extinctions, and metallicity. While we find general agreement with published distances when we make similar systematic assumptions, there is a clear problem in the standard distances because they require Cepheids with negative extinctions, particularly in low metallicity galaxies, unless the mean LMC extinction exceeds E(B-V) > 0.25. The problem can be explained by the physically expected metallicity dependence of the Cepheid distance scale, where metal-poor Cepheids are hotter and fainter than metal-rich Cepheids. For V and I we found that the mean magnitude change is -0.14 +/- 0.14 mag/dex and the mean color change is 0.13 +/- 0.04 mag/dex, with the change in color dominating the change in distance. The effect on Type Ia supernova estimates of the Hubble constant is dramatic because most were found in the metal poor galaxies with the bluest Cepheids. The Type Ia Multi-color Light Curve Shape (MLCS) method estimate for H_0 formally rises from 69 +/- 8 km/s Mpc to 80 +/- 6 km/s Mpc with the metallicity correction.Comment: 54 pages, 7 figures, 4 tables, submitted to Ap

DNA damage predicts prognosis and treatment response in colorectal liver metastases superior to immunogenic cell death and T cells

Preclinical models indicate that DNA damage induces type I interferon (IFN), which is crucial for the induction of an anti-tumor immune response. In human cancers, however, the association between DNA damage and an immunogenic cell death (ICD), including the release and sensing of danger signals, the subsequent ER stress response and a functional IFN system, is less clear. Methods: Neoadjuvant-treated colorectal liver metastases (CLM) patients, undergoing liver resection in with a curative intent, were retrospectively enrolled in this study (n=33). DNA damage (gammaH2AX), RNA and DNA sensors (RIG-I, DDX41, cGAS, STING), ER stress response (p-PKR, p-eIF2alpha, CALR), type I and type II IFN- induced proteins (MxA, GBP1), mature dendritic cells (CD208), and cytotoxic and memory T cells (CD3, CD8, CD45RO) were investigated by an immunohistochemistry whole-slide tissue scanning approach and further correlated with recurrence-free survival (RFS), overall survival (OS), radiographic and pathologic therapy response. Results: gammaH2AX is a negative prognostic marker for RFS (HR 1.32, 95% CI 1.04-1.69, p=0.023) and OS (HR 1.61, 95% CI 1.23-2.11, p<0.001). A model comprising of DDX41, STING and p-PKR predicts radiographic therapy response (AUC=0.785, p=0.002). gammaH2AX predicts prognosis superior to the prognostic value of CD8. CALR positively correlates with GBP1, CD8 and cGAS. A model consisting of gammaH2AX, p-eIF2alpha, DDX41, cGAS, CD208 and CD45RO predicts pathological therapy response (AUC=0.944, p<0.001). Conclusion: In contrast to preclinical models, DNA damage inversely correlated with ICD and its associated T cell infiltrate and potentially serves as a therapeutic target in CLM

Morphologic and Molecular Features of Hepatocellular Adenoma with Gadoxetic Acid-enhanced MR Imaging

Purpose To evaluate the diagnostic performance of imaging features of gadoxetic acid-enhanced magnetic resonance (MR) imaging to differentiate among hepatocellular adenoma (HCA) subtypes by using the histopathologic results of the new immunophenotype and genotype classification and to correlate the enhancement pattern on the hepatobiliary phase (HBP) with the degrees of expression of organic anion transporting polypeptide (OATP1B1/3), multidrug resistance-associated protein 2 (MRP) (MRP2), and MRP 3 (MRP3) transporters. Materials and Methods This retrospective study was approved by the institutional review board, and the requirement for informed consent waived. MR imaging findings of 29 patients with 43 HCAs were assessed by two radiologists independently then compared with the histopathologic analysis as the standard of reference. Receiver operating characteristic curves and Spearman rank correlation coefficient were used to test the diagnostic performance of gadoxetic acid-enhanced MR imaging features, which included the retention or washout at HBP and degree of transporter expression. Interreader agreement was assessed by using the κ statistic with 95% confidence interval. Results The area under the curve for the diagnosis of inflammatory HCA was 0.79 (95% confidence interval: 0.64, 0.90); for the steatotic type, it was 0.90 (95% confidence interval: 0.77, 0.97); and for the β-catenin type, it was 0.87 (95% confidence interval: 0.74, 0.95). There were no imaging features that showed a significant statistical correlation for the diagnosis of unclassified HCAs. On immunohistochemical staining, OATP1B1/3 expression was the main determinant for the retention, whereas MRP3 was the key determinant for washout of gadoxetic acid at HBP (P < .001). MRP2 appeared to have no role. Conclusion Gadoxetic acid-enhanced MR imaging features may suggest the subtype of HCA. The degree of OATP1B1/3 and MRP3 expression correlated statistically with gadoxetic acid retention and washout, respectively, in the HBP. (©) RSNA, 2015 Online supplemental material is available for this article

The Hubble Space Telescope Extragalactic Distance Scale Key Project. X. The Cepheid Distance to NGC 7331

The distance to NGC 7331 has been derived from Cepheid variables observed with HST/WFPC2, as part of the Extragalactic Distance Scale Key Project. Multi-epoch exposures in F555W (V) and F814W (I), with photometry derived independently from DoPHOT and DAOPHOT/ALLFRAME programs, were used to detect a total of 13 reliable Cepheids, with periods between 11 and 42 days. The relative distance moduli between NGC 7331 and the LMC, imply an extinction to NGC 7331 of A_V = 0.47+-0.15 mag, and an extinction-corrected distance modulus to NGC 7331 of 30.89+-0.14(random) mag, equivalent to a distance of 15.1 Mpc. There are additional systematic uncertainties in the distance modulus of +-0.12 mag due to the calibration of the Cepheid Period-Luminosity relation, and a systematic offset of +0.05+-0.04 mag if we applied the metallicity correction inferred from the M101 results of Kennicutt et al 1998.Comment: To be published in The Astrophysical Journal, 1998 July 1, v501 note: Figs 1 and 2 (JPEG files) and Fig 7 (multipage .eps file) need to be viewed/printed separatel

Characterisation of the magnetic field of the Herbig Be star HD 200775

After our recent discovery of four magnetic Herbig stars, we have decided to study in detail one of them, HD 200775, to determine if its magnetic topology is similar to that of the main sequence magnetic stars. With this aim, we monitored this star in Stokes I and V over more than two years, using the new spectropolarimeters ESPaDOnS at CFHT, and Narval at TBL. Using our data, we find that HD 200775 is a double-lined spectroscopic binary system, whose secondary seems similar, in temperature, to the primary. We determine the luminosity ratio of the system, and using the luminosity of the system found in literature, we derive the luminosity of both stars. From our measurements of the radial velocities of both stars we determine the ephemeris and the orbital parameters of the system. We have fitted 30 Stokes V profiles simultaneously, using a chi2 minimisation method, with a decentered-dipole model. The best-fit model provides a rotation period of 4.3281 d an inclination angle of 60 degrees, and a magnetic obliquity angle of 125 degrees. The polar strength of the magnetic dipole field is 1000 G, which is decentered by 0.05 R* from the center of the star. The derived magnetic field model is qualitatively identical to those commonly observed in the Ap/Bp stars, which bring strong argument in favour of the fossil field hypothesis, to explain the origin of the magnetic fields in the main sequence Ap/Bp stars. Our determination of the inclination of the rotation axis leads to a radius of the primary which is smaller than that derived from the HR diagram position. This can be explained by a larger intrinsic luminosity of the secondary relative to the primary, due to a larger circumstellar extinction of the secondary relative to the primary.Comment: Accepted for publication in MNRAS, 14 pages, 10 figure

The contribution of microlensing surveys to the distance scale

In the early nineties several teams started large scale systematic surveys of the Magellanic Clouds and the Galactic Bulge to search for microlensing effects. As a by product, these groups have created enormous time-series databases of photometric measurements of stars with a temporal sampling duration and accuracy which are unprecedented. They provide the opportunity to test the accuracy of primary distance indicators, such as Cepheids, RRLyrae stars, the detached eclipsing binaries, or the luminosity of the red clump. We will review the contribution of the microlensing surveys to the understanding of the physics of the primary distance indicators, recent differential studies and direct distance determinations to the Magellanic Clouds and the Galactic Bulge.Comment: Invited review article to appear in: `Post-Hipparcos Cosmic Candles', A. Heck & F. Caputo (Eds), Kluwer Academic Publ., Dordrecht, in press. 21 pages; uses Kluwer's crckapb.sty LaTeX style file, enclose