Interstellar 12C/13C from CH+ absorption lines: Results from an extended survey

The 12C/13C isotope ratio in the interstellar medium (ISM), and its evolution with time, is an important tracer of stellar yields. Spatial variations of this ratio can be used to study mixing in the ISM. We want to determine this ratio and its spatial variations in the local ISM from CH+ absorption lines in the optical towards early-type stars. The aim is to determine the average value for the local ISM and study possible spatial variations. We observed a large number of early-type stars with Feros to extend the sample of suitable target stars for CH+ isotope studies. The best suited targets were observed with Uves with higher signal-to-noise ratio and spectral resolution to determine the isotope ratio from the interstellar CH+ lines. This study significantly expands the number of 13CH+ detections. We find an average ratio of = 76.27 +- 1.94 or, for f = 1/R, = (120.46 +- 3.02) 10^{-4}. The scatter in f is 6.3 sigma(). This findings strengthens the case for chemical inhomogeneity in the local ISM, with important implications for the mixing in the ISM. Given the large scatter, the present-day value in the ISM is not significantly larger than the solar value, which corresponds to the local value 4.5 Gyr ago.Comment: 11 pages, 16 figures, 2 tables, A&A submitte

Using neural networks for high-speed blood cell classification in a holographic-microscopy flow-cytometry system

High-throughput cell sorting with flow cytometers is an important tool in modern clinical cell studies. Most cytometers use biomarkers that selectively bind to the cell, but induce significant changes in morphology and inner cell processes leading sometimes to its death. This makes label-based cell sorting schemes unsuitable for further investigation. We propose a label-free technique that uses a digital inline holographic microscopy for cell imaging and an integrated, optical neural network for high-speed classification. The perspective of dense integration makes it attractive to ultrafast, large-scale cell sorting. Network simulations for a ternary classification task (monocytes/granulocytes/lymphocytes) resulted in 89% accuracy

Comparison of primordial tensor power spectra from the deformed algebra and dressed metric approaches in loop quantum cosmology

Loop quantum cosmology tries to capture the main ideas of loop quantum gravity and to apply them to the Universe as a whole. Two main approaches within this framework have been considered to date for the study of cosmological perturbations: the dressed metric approach and the deformed algebra approach. They both have advantages and drawbacks. In this article, we accurately compare their predictions. In particular, we compute the associated primordial tensor power spectra. We show -- numerically and analytically -- that the large scale behavior is similar for both approaches and compatible with the usual prediction of general relativity. The small scale behavior is, the other way round, drastically different. Most importantly, we show that in a range of wavenumbers explicitly calculated, both approaches do agree on predictions that, in addition, differ from standard general relativity and do not depend on unknown parameters. These features of the power spectrum at intermediate scales might constitute a universal loop quantum cosmology prediction that can hopefully lead to observational tests and constraints. We also present a complete analytical study of the background evolution for the bouncing universe that can be used for other purposes.Comment: 15 pages, 7 figure

Housing cycles in the major euro area countries.

The recent burst of the house price bubble in the United States and its spillover effects on real economies worldwide has rekindled the interest in the role of housing in the business cycle. In this paper, we investigate the relationships between housing cycles among the four major euro area countries (Germany, France, Italy and Spain) over the sample 1980q1 – 2008q4. Our main findings are that GDP cycles between 1.5 and 8 years show a high degree of comovement across these four countries, reflecting trade linkages. In contrast comovements in housing market cycles between 1.5 and 8 years are much weaker, idiosyncratic factors playing a major role. House prices are even less related across countries than quantities (residential investment, building permits, housing starts …). We find however much stronger relationships since 1999, i.e. in the common monetary policy period.Housing cycles, synchronisation measures, euro area countries.

A Survey and Analysis of Aircraft Maintenance Metrics: A Balanced Scorecard Approach

Performance metrics have helped to sustain the Air Force, improve processes, and guided decisions makers through decades of challenges and change. The Air Force continues to change as it faces the challenges of an aging fleet coupled with the tightest budget constraints of modern times. The current metrics employed by the United States Air Force Aircraft Maintenance community have gone largely unchanged over decades despite a host of force altering events. The focus of this research is to evaluate current maintenance metrics and assess the utility of the Balanced Scorecard framework for use in a Maintenance Group. The researcher utilizes a mixed methodology to accomplish this evaluation, including survey research, statistical analysis, content analysis, and correlation analysis. The paper proposes a Maintenance Group Balanced Scorecard based on the analysis of survey responses from Maintenance Officers with Combat Air Forces (CAF) experience. The proposed Balanced Scorecard is comprised of existing, refined, and proposed metrics to measure each perspective category of the Balanced Scorecard, and is intended to help align maintenance metrics with organizational goals/objectives and the strategic goals of Maintenance Groups in CAF units

Technofixing the Future: Ethical Side Effects of Using AI and Big Data to meet the SDGs

While the use of smart information systems (the combination of AI and Big Data) offer great potential for meeting many of the UN’s Sustainable Development Goals (SDGs), they also raise a number of ethical challenges in their implementation. Through the use of six empirical case studies, this paper will examine potential ethical issues relating to use of SIS to meet the challenges in six of the SDGs (2, 3, 7, 8, 11, and 12). The paper will show that often a simple “technofix”, such as through the use of SIS, is not sufficient and may exacerbate, or create new, issues for the development community using SIS

The (B0+?)+O6 system FN CMa: A case for tidal-pulsational interaction?

FN CMa is visually double with a separation of about 0.6arcsec. Sixty high-cadence VLT/UVES spectra permit the A and B components to be disentangled, as the relative contribution of each star to the total light entering the spectrograph fluctuates between exposures due to changes in seeing. Component A exhibits rapid line-profile variations, leading us to attribute the photometric variability seen by HIPPARCOS (with a derived P=0.08866d) to this component. From a total of 122 archival and new echelle spectra it is shown that component A is an SB1 binary with an orbital period of 117.55 days. The eccentricity of 0.6 may result in tidal modulation of the pulsation(s) of component Aa.Comment: 2 pages, 1 figure, IAUS 272 - Active OB Stars: Structure, Evolution, Mass Loss and Critical Limit

The 2006 hot phase of Romano's star (GR 290) in M33

Understanding the nature of the instabilities of LBVs is important to understand the late evolutionary stages of very massive stars. We investigate the long term, S Dor-type variability of the luminous blue variable GR290 (Romano's star) in M33, and its 2006 minimum phase. New spectroscopic and photometric data taken in November and December 2006 were employed in conjunction with already published data on GR290 to derive the physical structure of GR290 in different phases and the time scale of the variability. We find that by the end of 2006, GR 290 had reached the deepest visual minimum so far recorded. Its present spectrum resembles closely that of the Of/WN9 stars, and is the hottest so far recorded in this star (and in any LBV as well), while its visual brightness decreased by about 1.4 mag. This first spectroscopic record of GR290 during a minimum phase confirms that, similarly to AG Car and other LBVs, the star is subject to ample S Dor-type variations, being hotter at minimum, suggesting that the variations take place at constant bolometric luminosity.Comment: 4 figures, 1 table, accepted for publication in A&A Letter