Interplay between pulsations and mass loss in the blue supergiant 55 Cygnus = HD 198478

Blue supergiant stars are known to display photometric and spectroscopic variability that is suggested to be linked to stellar pulsations. Pulsational activity in massive stars strongly depends on the star's evolutionary stage and is assumed to be connected with mass-loss episodes, the appearance of macroturbulent line broadening, and the formation of clumps in the wind. To investigate a possible interplay between pulsations and mass-loss, we carried out an observational campaign of the supergiant 55 Cyg over a period of five years to search for photospheric activity and cyclic mass-loss variability in the stellar wind. We modeled the H, He I, Si II and Si III lines using the nonlocal thermal equilibrium atmosphere code FASTWIND and derived the photospheric and wind parameters. In addition, we searched for variability in the intensity and radial velocity of photospheric lines and performed a moment analysis of the line profiles to derive frequencies and amplitudes of the variations. The Halpha line varies with time in both intensity and shape, displaying various types of profiles: P Cygni, pure emission, almost complete absence, and double or multiple peaked. The star undergoes episodes of variable mass-loss rates that change by a factor of 1.7-2 on different timescales. We also observe changes in the ionization rate of Si II and determine a multiperiodic oscillation in the He I absorption lines, with periods ranging from a few hours to 22.5 days. We interpret the photospheric line variations in terms of oscillations in p-, g-, and strange modes. We suggest that these pulsations can lead to phases of enhanced mass loss. Furthermore, they can mislead the determination of the stellar rotation. We classify the star as a post-red supergiant, belonging to the group of alpha Cyg variables.Comment: 20 pages, 18 figures, 3 tables, accepted to Astronomy & Astrophysic

Implementación de mejoras para la cría en cautiverio de colonias del abejorro nativo Bombus pauloensis (= B. atratus) (Hymenoptera: Apoidea)

Nuestro grupo de investigación ha logrado emplear exitosamente colonias del abejorro Bombus pauloensis criadas en cautiverio para la polinización de tomate; sin embargo, falta aun establecer las condiciones que permitan la producción de sexuados y el efecto que tienen las condiciones de invernadero sobre las colonias. Con esto se busca desarrollar un modelo tecnificado de producción en cautiverio. Se hizo seguimiento a una colonia de B. pauloensis desde la iniciación en la cámara de cría a partir de una reina silvestre, el desarrollo en un cultivo de tomate bajo invernadero, hasta la producción, selección y cruce de nuevas reinas. En cautiverio se evaluó el efecto de la alimentación de larvas vía bolsillo en el peso de los individuos emergidos. Se obtuvieron obreras de 0,26 g en promedio. Estas obreras fueron de mayor peso que las obtenidas sin este tipo de alimentación en otros trabajos. En el invernadero se registró el número de obreras forrajeras, las visitas en tres momentos del día y el porcentaje de flores polinizadas. Se presentó la mayor actividad forrajera a las 10:00 a.m con 81% de flores polinizadas en promedio. Adicionalmente, se hizo un censo del número de nuevas reinas y el tiempo en alcanzar el punto de cambio. Este se presentó después de 172 días a partir de la primera oviposición por parte de la reina fundadora y se obtuvieron 53 reinas nuevas de las cuales 37 se seleccionaron por su mayor tamaño para ser cruzadas y 26 se cruzaron exitosamente en cautiverio

Restoration of Hypoglycemia Awareness After Islet Transplantation

OBJECTIVE—To determine the impact of islet transplantation (ITx) on hypoglycemia awareness in patients with unstable type 1 diabetes and its relation to islet function

Differences in the gas and dust distribution in the transitional disk of a sun-like young star, PDS 70

We present ALMA 0.87 mm continuum, HCO+ J=4--3 emission line, and CO J=3--2 emission line data of the disk of material around the young, Sun-like star PDS 70. These data reveal the existence of a possible two component transitional disk system with a radial dust gap of 0."2 +/- 0."05, an azimuthal gap in the HCO+ J=4--3 moment zero map, as well as two bridge-like features in the gas data. Interestingly these features in the gas disk have no analogue in the dust disk making them of particular interest. We modeled the dust disk using the Monte Carlo radiative transfer code HOCHUNK3D (Whitney et al. 2013) using a two disk components. We find that there is a radial gap that extends from 15-60 au in all grain sizes which differs from previous work

The CMS Magnetic Field Map Performance

Peer reviewe

Rationale and design of a multicenter Chronic Kidney Disease (CKD) and at-risk for CKD electronic health records-based registry: CURE-CKD.

BACKGROUND: Chronic kidney disease (CKD) is a global public health problem, exhibiting sharp increases in incidence, prevalence, and attributable morbidity and mortality. There is a critical need to better understand the demographics, clinical characteristics, and key risk factors for CKD; and to develop platforms for testing novel interventions to improve modifiable risk factors, particularly for the CKD patients with a rapid decline in kidney function. METHODS: We describe a novel collaboration between two large healthcare systems (Providence St. Joseph Health and University of California, Los Angeles Health) supported by leadership from both institutions, which was created to develop harmonized cohorts of patients with CKD or those at increased risk for CKD (hypertension/HTN, diabetes/DM, pre-diabetes) from electronic health record data. RESULTS: The combined repository of candidate records included more than 3.3 million patients with at least a single qualifying measure for CKD and/or at-risk for CKD. The CURE-CKD registry includes over 2.6 million patients with and/or at-risk for CKD identified by stricter guide-line based criteria using a combination of administrative encounter codes, physical examinations, laboratory values and medication use. Notably, data based on race/ethnicity and geography in part, will enable robust analyses to study traditionally disadvantaged or marginalized patients not typically included in clinical trials. DISCUSSION: CURE-CKD project is a unique multidisciplinary collaboration between nephrologists, endocrinologists, primary care physicians with health services research skills, health economists, and those with expertise in statistics, bio-informatics and machine learning. The CURE-CKD registry uses curated observations from real-world settings across two large healthcare systems and has great potential to provide important contributions for healthcare and for improving clinical outcomes in patients with and at-risk for CKD

Wind modelling of very massive stars up to 300 solar masses

Some studies have claimed a universal stellar upper-mass limit of 150 Msun. A factor that is often overlooked is that there might be a difference between the current and initial masses of the most massive stars, as a result of mass loss. We present Monte Carlo mass-loss predictions for very massive stars in the range 40-300 Msun, with large luminosities and Eddington factors Gamma. Using our new dynamical approach, we find an upturn in the mass-loss vs. Gamma dependence, at the point where the winds become optically thick. This coincides with the location where wind efficiency numbers surpass the single-scattering limit of Eta = 1, reaching values up to Eta = 2.5. Our modelling suggests a transition from common O-type winds to Wolf-Rayet characteristics at the point where the winds become optically thick. This transitional behaviour is also revealed with respect to the wind acceleration parameter beta, which starts at values below 1 for the optically thin O-stars, and naturally reaches values as high as 1.5-2 for the optically thick Wolf-Rayet models. An additional finding concerns the transition in spectral morphology of the Of and WN characteristic He II line at 4686 Angstrom. When we express our mass-loss predictions as a function of the electron scattering Gamma_e (=L/M) only, we obtain a mass-loss Gamma dependence that is consistent with a previously reported power-law Mdot propto Gamma^5 (Vink 2006) that was based on our semi-empirical modelling approach. When we express Mdot in terms of both Gamma and stellar mass, we find Mdot propto M^0.8 Gamma^4.8 for our high Gamma models. Finally, we confirm that the Gamma-effect on the mass-loss predictions is much stronger than that of an increased helium abundance, calling for a fundamental revision in the way mass loss is incorporated in evolutionary models of the most massive stars.Comment: minor language changes (Astronomy & Astrophysics in press - 11 pages, 10 figures

Discovery of Small-Scale Spiral Structures in the Disk of SAO 206462 (HD 135344B): Implications for the Physical State of the Disk from Spiral Density Wave Theory

We present high-resolution, H-band, imaging observations, collected with Subaru/HiCIAO, of the scattered light from the transitional disk around SAO 206462 (HD 135344B). Although previous sub-mm imagery suggested the existence of the dust-depleted cavity at r~46AU, our observations reveal the presence of scattered light components as close as 0.2" (~28AU) from the star. Moreover, we have discovered two small-scale spiral structures lying within 0.5" (~70AU). We present models for the spiral structures using the spiral density wave theory, and derive a disk aspect ratio of h~0.1, which is consistent with previous sub-mm observations. This model can potentially give estimates of the temperature and rotation profiles of the disk based on dynamical processes, independently from sub-mm observations. It also predicts the evolution of the spiral structures, which can be observable on timescales of 10-20 years, providing conclusive tests of the model. While we cannot uniquely identify the origin of these spirals, planets embedded in the disk may be capable of exciting the observed morphology. Assuming that this is the case, we can make predictions on the locations and, possibly, the masses of the unseen planets. Such planets may be detected by future multi-wavelengths observations.Comment: 8 pages, 5 figures, ApJL in press, typo correcte