The Be-test in the Li-rich star \#1657 of NGC 6397: evidence for Li-flash in RGB stars?

The Li-rich turn-off star in the globular cluster NGC 6397 could represent the smoking gun for some very rare episode of Li enrichment in globular clusters. We aim to understand the nature of the Li enrichment by performing a spectroscopic analysis of the star, in particular of its beryllium (Be) abundance, and by investigating its binary nature. We observe the near UV region where the Beii resonance doublet and the NH bands are located. We could not detect the Beii lines and derive an upper limit of log (Be/H)< -12.2, that is consistent with the Be observed in other stars of the cluster. We could detect a weak G-band, which implies a mild carbon enhancement [C/Fe]$+0.4\pm0.2$. We could not detect the UV NH band, and we derive an upper limit [N/Fe]$< 0.0$. For oxygen we could notdetect any of the near UV OH lines, which implies that oxygen cannot be strongly enhanced in this star. This is consistent with the detection of the Oi triplet at 777nm, which is consistent with [O/Fe]~0.5. Combining the UVES and Mike data, we could not detect any variation in the radial velocity greater than 0.95 kms$^{-1}$ over 8 years. The chemical composition of the star strongly resembles that of `first generation' NGC6397 stars, with the huge Li as the only deviating abundance. Not detecting Be rules out two possible explanations of the Li overabundance: capture of a substellar body and spallation caused by a nearby type II SNe. Discrepancies are also found with respect to other accretion scenarios,except for contamination by the ejecta of a star that has undergone the RGB Li-flash.Comment: Accepted for publication in A&

Capital structure and its determinants in the United Kingdom – a decompositional analysis

Prior research on capital structure by Rajan and Zingales (1995) suggests that the level of gearing in UK companies is positively related to size and tangibility, and negatively correlated with profitability and the level of growth opportunities. However, as argued by Harris and Raviv (1991), 'The interpretation of results must be tempered by an awareness of the difficulties involved in measuring both leverage and the explanatory variables of interest'. In this study the focus is on the difficulties of measuring gearing, and the sensitivity of Rajan and Zingales' results to variations in gearing measures are tested. Based on an analysis of the capital structure of 822 UK companies, Rajan and Zingales' results are found to be highly definitional-dependent. The determinants of gearing appear to vary significantly, depending upon which component of debt is being analysed. In particular, significant differences are found in the determinants of long- and short-term forms of debt. Given that trade credit and equivalent, on average, accounts for more than 62% of total debt, the results are particularly sensitive to whether such debt is included in the gearing measure. It is argued, therefore, that analysis of capital structure is incomplete without a detailed examination of all forms of corporate debt

Making SPIFFI SPIFFIER: Upgrade of the SPIFFI instrument for use in ERIS and performance analysis from re-commissioning

SPIFFI is an AO-fed integral field spectrograph operating as part of SINFONI on the VLT, which will be upgraded and reused as SPIFFIER in the new VLT instrument ERIS. In January 2016, we used new technology developments to perform an early upgrade to optical subsystems in the SPIFFI instrument so ongoing scientific programs can make use of enhanced performance before ERIS arrives in 2020. We report on the upgraded components and the performance of SPIFFI after the upgrade, including gains in throughput and spatial and spectral resolution. We show results from re-commissioning, highlighting the potential for scientific programs to use the capabilities of the upgraded SPIFFI. Finally, we discuss the additional upgrades for SPIFFIER which will be implemented before it is integrated into ERIS.Comment: 20 pages, 12 figures. Proceedings from SPIE Astronomical Telescopes and Instrumentation 201

Comparative interactomics analysis of different ALS-associated proteins identifies converging molecular pathways

Amyotrophic lateral sclerosis (ALS) is a devastating neurological disease with no effective treatment available. An increasing number of genetic causes of ALS are being identified, but how these genetic defects lead to motor neuron degeneration and to which extent they affect common cellular pathways remains incompletely understood. To address these questions, we performed an interactomic analysis to identify binding partners of wild-type (WT) and ALS-associated mutant versions of ATXN2, C9orf72, FUS, OPTN, TDP-43 and UBQLN2 in neuronal cells. This analysis identified several known but also many novel binding partners of these proteins

Three-dimensional distribution of ejecta in Supernova 1987A at 10 000 days

Due to its proximity, SN 1987A offers a unique opportunity to directly observe the geometry of a stellar explosion as it unfolds. Here we present spectral and imaging observations of SN 1987A obtained ~10,000 days after the explosion with HST/STIS and VLT/SINFONI at optical and near-infrared wavelengths. These observations allow us to produce the most detailed 3D map of H-alpha to date, the first 3D maps for [Ca II] \lambda \lambda 7292, 7324, [O I] \lambda \lambda 6300, 6364 and Mg II \lambda \lambda 9218, 9244, as well as new maps for [Si I]+[Fe II] 1.644 \mu m and He I 2.058 \mu m. A comparison with previous observations shows that the [Si I]+[Fe II] flux and morphology have not changed significantly during the past ten years, providing evidence that it is powered by 44Ti. The time-evolution of H-alpha shows that it is predominantly powered by X-rays from the ring, in agreement with previous findings. All lines that have sufficient signal show a similar large-scale 3D structure, with a north-south asymmetry that resembles a broken dipole. This structure correlates with early observations of asymmetries, showing that there is a global asymmetry that extends from the inner core to the outer envelope. On smaller scales, the two brightest lines, H-alpha and [Si I]+[Fe II] 1.644 \mu m, show substructures at the level of ~ 200 - 1000 km/s and clear differences in their 3D geometries. We discuss these results in the context of explosion models and the properties of dust in the ejecta.Comment: Accepted for publication in Ap

Peculiarities of selecting the gearboxes and wheel shift coefficients in the optimization of drive gear transmissions

В якості вузлового моменту оптимізаційного проектування тягових зубчастих передач залізничного рухомого складу виділено процедуру обґрунтованого вибору коефіцієнтів зміщення шестерень і коліс за рахунок використання відповідних блокувальних контурів. Обґрунтовано актуальність досліджень з розроблення методичного забезпечення для раціонального отримання блокувальних контурів при проектуванні тягових зубастих передач. Представлені розроблені математичні залежності, що пов’язують фіксовані величині обмежувальних і контрольованих параметрів передач з числами зубців і коефіцієнтами зміщення шестерні та колеса. Їх використання дозволяє отримувати конкретні блокувальні контури для вибору коефіцієнтів зміщення шестерні та колеса при оптимізаційному проектуванні тягових зубчастих передач з різними початковими параметрами. Наведено приклад практичної реалізації розроблених математичних залежностей при отриманні блокувального контуру для вибору коефіцієнтів зміщення шестерні та колеса тягової зубчастої передачі сучасного магістрального вантажного тепловозу. Зроблено висновок про доцільність використання запропонованого методичного забезпечення при оптимізаційному проектуванні тягових зубчатих передач.As a key point in the optimization design of traction gears of the railway rolling stock, a procedure for a reasonable choice of the coefficients for the displacement of gears and wheels is provided by using the appropriate blocking circuits. The relevance of studies on the development of methodological support for the rational production of blocking contours in the design of traction-toothed gears is substantiated. The developed mathematical dependences connecting the fixed values of the limiting and controlled parameters of the gears with the numbers of the teeth and the gearing coefficients of the gears and wheels are presented. Their use makes it possible to obtain specific blocking contours for the selection of gear and wheel bias coefficients in the optimization design of traction gears with different initial parameters. An example of the practical implementation of the developed mathematical dependencies in obtaining a blocking contour for selecting the gear displacement coefficients and the traction gear wheel of a modern mainline freight locomotive is given. The conclusion is made about the expediency of using the proposed methodological support in the optimization design of traction gears

The short term debt vs. long term debt puzzle: a model for the optimal mix

This paper argues that the existing finance literature is inadequate with respect to its coverage of capital structure of small and medium sized enterprises (SMEs). In particular it is argued that the cost of equity (being both conceptually ill defined and empirically non quantifiable) is not applicable to the capital structure decisions for a large proportion of SMEs and the optimal capital structure depends only on the mix of short and long term debt. The paper then presents a model, developed by practitioners for optimising the debt mix and demonstrates its practical application using an Italian firm's debt structure as a case study

How does subjective well-being evolve with age? A literature review

This literature review provides an overview of the theoretical and empirical research in several disciplines on the relation between ageing and subjective well-being, i.e., how subjective well-being evolves across the lifespan. Because of the different methodologies, data sets and samples used, comparison among disciplines and studies is difficult. However, extant studies do show either a U-shaped, inverted U-shaped or linear relation between ageing and subjective well-being

Kapitalstrukturen börsennotierter Aktiengesellschaften - Deutschland und USA im Vergleich

Bisherige Evidenz über Kapitalstrukturunterschiede zwischen Deutschland und den USA deutet auf eine durchschnittlich höhere Verschuldung deutscher Unternehmen hin. Die vergangenen Jahre waren in Deutschland jedoch durch eine Förderung der Eigenkapitalfinanzierung seitens des deutschen Gesetzgebers und der Regulierungsbehörden geprägt. Die vorliegende Arbeit untersucht, inwieweit sich diese Änderungen tatsächlich auf den Verschuldungsgrad deutscher Unternehmen auswirken und ob es zu einer Annäherung an amerikanische Unternehmen kommt. Zu diesem Zweck werden durchschnittliche Verschuldungsgrade von US-amerikanischen und deutschen börsennotierten Gesellschaften über einen Zeitraum von 10 Jahren verglichen. Die Untersuchung zeigt, dass diese Änderungen vor allem den Verschuldungsgrad von Unternehmen beeinflusst haben, die erst in den letzten Jahren an einer deutschen Börse notiert wurden. Bei am deutschen Kapitalmarkt etablierten Unternehmen hingegen lässt sich keine aufgrund der neuen Rahmenbedingungen vorgenommene Anpassung der Verschuldungspolitik erkennen. Abstract Existing comparative evidence on corporate capital structure decisions in the U.S. and Germany traditionally reveals that German firms chose substantially higher levels of debt financing. Within the past years, however, Germany has experienced repeated initiatives by both legislative and regulatory bodies to promote equity finance. This paper tries to shed first light on how these initiatives affect the debt-equity-decision of German corporations and whether a convergence of German leverage levels to Anglo-American financing patterns can be observed. For this purpose we compare capital structures for a panel of U.S. and German public corporations over the past 10 years. The obtained evidence suggests that aggregate leverage ratios do indeed converge. Yet this development is primarily driven by recent German IPOs which seem to respond to the revamped institutional setting by choosing higher levels of equity. Established German corporations, by contrast, do not seem to have systematically adapted their financing patterns over the past decade

Massive Stars In The W33 Giant Molecular Complex

Rich in H II regions, giant molecular clouds are natural laboratories to study massive stars and sequential star formation. The Galactic star-forming complex W33 is located at = ∼ ◦ l 12.8 and at a distance of 2.4 kpc and has a size of ≈10 pc and a total mass of ≈(0.8−8.0) × 105 M⊙. The integrated radio and IR luminosity of W33—when combined with the direct detection of methanol masers, the protostellar object W33A, and the protocluster embedded within the radio source W33 main—mark the region as a site of vigorous ongoing star formation. In order to assess the long-term star formation history, we performed an infrared spectroscopic search for massive stars, detecting for the first time 14 early-type stars, including one WN6 star and four O4–7 stars. The distribution of spectral types suggests that this population formed during the past ∼2–4 Myr, while the absence of red supergiants precludes extensive star formation at ages 6–30 Myr. This activity appears distributed throughout the region and does not appear to have yielded the dense stellar clusters that characterize other star-forming complexes such as Carina and G305. Instead, we anticipate that W33 will eventually evolve into a loose stellar aggregate, with Cyg OB2 serving as a useful, albeit richer and more massive, comparator. Given recent distance estimates, and despite a remarkably similar stellar population, the rich cluster Cl 1813–178 located on the northwest edge of W33 does not appear to be physically associated with W33