Family Values: Ownership Structure, Performance and Capital Structure of Canadian Firms

This study examines how family ownership affects the performance and capital structure of 613 Canadian firms using a panel dataset from 1998 to 2005. In particular, we distinguish the effect of family ownership from the use of control-enhancing mechanisms. We find that freestanding family-owned firms with a single share class have similar market performance than other firms based on Tobin's q ratios, superior accounting performance based on ROA, and higher financial leverage based on debt-to-total assets. By contrast, family-owned firms that use dual-class shares have valuations that are lower by 17% on average relative to widely-held firms, despite having similar ROA and financial leverage. Finally, concentrated ownership by either a corporation or a financial institution does not significantly affect firm performance.Financial markets; International topics

Lithium in the Upper Centaurus Lupus and Lower Centaurus Crux Subgroups of Scorpius-Centaurus

We utilize spectroscopically derived model atmosphere parameters and the \ion{Li}{1} $\lambda6104$ subordinate line and the $\lambda6708$ doublet to derive lithium abundances for 12 members of the Upper-Centaurus Lupus (UCL) and Lower-Centaurus Crux (LCC) subgroups of the Scorpius Centaurus OB Association. The results indicate any intrinsic Li scatter in our 0.9-1.4 $M_{\odot}$ stars is limited to ${\sim}0.15$ dex, consistent with the lack of dispersion in ${\ge}1.0$ $M_{\odot}$ stars in the 100 Myr Pleiades and 30-50 Myr IC 2391 and 2602 clusters. Both ab initio uncertainty estimates and the derived abundances themselves indicate that the $\lambda$6104 line yields abundances with equivalent or less scatter than is found from the $\lambda$6708 doublet as a result of lower uncertainties for the subordinate feature, a result of low sensitivity to broadening in the subordinate feature. Because NLTE corrections are less susceptible to changes in surface gravity and/or metallicity for the 6104 {\AA} line, the subordinate Li feature is preferred for deriving lithium abundances in young Li-rich stellar association stars with $T_{\rm eff}{\ge}5200$ K.Comment: Accepted for publication in Astronomical Journal (abstract shortened for astro-ph submission

Spectroscopic Abundances and Membership in the Wolf 630 Moving Group

The concept of kinematic assemblages evolving from dispersed stellar clusters has remained contentious since Eggen’s initial formulation of moving groups in the 1960s. With high-quality parallaxes from the Hipparcos space astrometry mission, distance measurements for thousands of nearby, seemingly isolated stars are currently available. With these distances, a high-resolution spectroscopic abundance analysis can be brought to bear on the alleged members of these moving groups. If a structure is a relic of an open cluster, the members can be expected to be monolithic in age and abundance in as much as homogeneity is observed in young open clusters. In this work, we have examined 34 putative members of the proposed Wolf 630 moving group using high-resolution stellar spectroscopy. The stars of the sample have been chemically tagged to determine abundance homogeneity and confirm the existence of a homogeneous subsample of 19 stars. Fitting the homogeneous subsample with Yale–Yonsei isochrones yields a single evolutionary sequence of ∼2.7 ± 0.5 Gyr. It is concluded that this 19 star subsample of the Wolf 630 moving group sample of 34 stars could represent a dispersed cluster with an [Fe/H]=−0.01 ± 0.02 and an age of 2.7 ± 0.5 Gyr. In addition, chemical abundances of Na and Al in giants are examined for indications of enhancements as observed in field giants of old open clusters; overexcitation/ionization effects are explored in the cooler dwarfs of the sample; and oxygen is derived from the infrared triplet and the forbidden line at λ6300

Epsilon Indi Ba, Bb: a spectroscopic study of the nearest known brown dwarfs

The discovery of Epsilon Indi Ba and Bb, a nearby binary brown dwarf system with a main-sequence companion, allows a concerted campaign to characterise the physical parameters of two T dwarfs providing benchmarks against which atmospheric and evolutionary models can be tested. Some recent observations suggest the models at low mass and intermediate age may not reflect reality with, however, few conclusive tests. We are carrying out a comprehensive characterisation of these, the nearest known brown dwarfs, to allow constraints to be placed upon models of cool field dwarfs. We present broadband photometry from the V- to M-band and the individual spectrum of both components from 0.6-5.1 microns at a resolution of up to R=5000. A custom analytic profile fitting routine was implemented to extract the blended spectra and photometry of both components separated by 0.7 arcsec. We confirm the spectral types to be T1 and T6, and notably, we do not detect lithium at 6708A in the more massive object which may be indicative both of the age of the system and the mass of the components.Comment: 4 pages, 2 figures, to appear in proceedings of Cool Stars 1

Beryllium Abundances in F and G Dwarfs in the Coma Cluster and the Ursa Major Group from Keck HIRES Observation

The study of both light elements Li and Be in open clusters of known properties can reveal the internal structure and the mechanisms of mixing in main-sequence stars as a function of age and composition. In previous work, we have investigated the older Hyades cluster and the younger Pleiades and Per clusters. The Coma Berenices cluster and the UMa moving group are intermediate in age between the Hyades and Pleiades and provide a good linchpin for the influence of stellar age on light-element abundances; there are dips in the mid-F stars in both Li and Be in the Hyades but no Be dip and only a minor Li dip in the Pleiades. We have made observations of the resonance doublet of Be ii near 3130 A ˚ in 13 Coma and six UMa stars with the Keck I telescope and the High Resolution Echelle Spectrometer. The Be abundances were determined by spectrum synthesis. In the F dwarfs in Coma, there are both Li and Be deficiencies, indicating that the deple-tions occur during the main-sequence phase of evolution but do not become evident until an age of 200–300 Myr. For both UMa and Coma stars, the Li depletion is greater than the Be depletion at all temperatures, but there is little, if any, Be depletion in stars with Teff \u3c 6000 K. In the four clusters studied for Be, the mean Be abundance for stars with temperatures less than 6000 K is log NðBe=HÞþ12:00 ¼1:27, independent of age or metal content. For the hotter stars (5850–6680 K), the Li and Be abundances are correlated, indicating that the depletion probably occurs simultaneously; this matches the results for the field stars and the Hyades and the predictions of Li and Be depletion by rotationally induced mixing

Beryllium Abundances in F and G Dwarfs in the Pleiades and a Persei Clusters from Keck High-Resolution Echelle Spectrometer Observations

While there are many observations of Li in open clusters, there are very few of the companion light element Be. As we have seen in the study of Be in the Hyades by Boesgaard & King, the two elements together provide important and unique information on the extent and nature of interior mixing in solar-like stars. We have obtained high-resolution (45,000) spectra of the Be ii resonance lines in the 14 Pleiades and four Per dwarfs of spectral types F and G with the Keck I telescope and High-Resolution Echelle Spectrometer. The signal-to-noise ratio in the Be spectral region is typically 40 pixelÀ1. These twoclusters have similar ages and have solar metallicity. Abundances of Be were determined by spectrum synthesis using the newest version of MOOG. For the F dwarfs where there is only a weak Li dip, there is no indication of a Be dip as was found in the Hyades in association with its deep Li dip. Thus, the observed light element depletion in the F dwarfs in the Hyades and in field stars is occurring during main-sequence evolution, and Be depletion does not become evident until ages of more than 100 Myr. The Pleiades G dwarfs are apparently undepleted in Be and the mean value for log NðBe=HÞþ12:00 in stars cooler than 6000 K is 1:26 Æ0:10, compared to the Hyades mean of 1:31 Æ0:07. The star-to-star dispersion in Be in the Pleiades is comparable to the quoted errors. The four Per stars have lower Be abundances than the Pleiades with a mean of 1.02 dex. The differences in these twoclusters in their Li and Be abundances relative to the Hyades is thought tobe due totheir younger age and possibly their lower metallicity

Node-Oriented Workflow (NOW): A Command Template Workflow Management Tool for High Throughput Data Analysis Pipelines

Next generation sequencing (NGS) systems produce vast quantities of data that require substantial computational resources for typical analysis tasks. In addition, data that are generated by different NGS systems are not homogeneous. Moreover, there are an overwhelming number of tools available for performing typical tasks. Managing NGS workflows involves writing custom scripts that quickly grow in complexity, often resulting in unwieldy workflows that underutilize typical high performance compute resources, and increase the demands of the staff managing these workflows. We present Node-Oriented Workflow (NOW), a dynamic command template workflow engine for high performance distributed computing (HPC) systems. Our system provides a simple-to-use browser-based front end for designing and managing complex workflows. Workflows are configured using a simple browser interface, and are managed by the integrated job engine, which initializes nodes, monitors node status, and processes results of individual jobs across nodes in an HPC configuration. We reduce excessive messaging across nodes by placing the burden on nodes to start tasks in a workflow when dependencies are met, i.e., node oriented workflow. Our system was designed for NGS processing in the clinical research setting, emphasizing user simplicity, tool scalability, minimization of redundancy in workflows, while maximizing throughput in an HPC environment. Furthermore, NOW is not restricted to NGS pipeline management, but can used to manage any computational pipeline

Beryllium Abundances in F and G Dwarfs in Praesepe and Other Young Clusters from Keck HIRES Observations

The study of both Be and Li gives useful clues about stellar internal structure. Of particular interest is the study of these light elements in open clusters, which have a known age and metallicity. In this paper we present a study of Be abundances in 10 F-type stars in Praesepe and a comprehensive discussion about Be abundances in other open clusters: Hyades, Pleiades, Per, Coma, and UMa. We have made observations of the doublet of Be ii around 3130 A˚ in Praesepe stars, using the Keck I telescope and the High Resolution Echelle Spectrometer (HIRES). Beryllium abundances were derived from the spectra using the spectrum synthesis method. We find four stars with definite Be depletion in the temperature range of the Li dip like we found in our previous cluster studies, notably for the Hyades and Coma clusters. Putting all the clusters together, we confirm the existence of a Be dip in a narrow temperature range for F stars. Beryllium depletion in this dip is less pronounced than Li depletion. For the cooler stars there is little or no Be depletion, even though there are large depletions of Li. For stars that have little or no Li depletion, AðLiÞ! 3:0, the ratio Li/Be is 75 Æ 4:6, compared to the meteoritic ratio of 77.6. For stars cooler than $5900 K there appears to be little or no Be depletion, and the mean A(Be) is 1:30 Æ 0:02. For these cooler stars within a given cluster there is no evidence for intrinsic star-to-star differences in A(Be), with the possible exception of the cool Pleiades stars. In the temperature range of the Li-Be dip, a strong correlation exists between Li and Be, consistent with the theory of rotationally induced mixing. Moreover, the slopes of the Li versus Be correlations are different depending on the temperature range. For the full sample of 42 stars between 5900 and 6650 K the slope is 0:43 Æ 0:05 [where A(Li) is the abscissa]. The slope is 0:48 Æ 0:08 for 6300 K \u3c TeA \u3c 6650 K and 0:30 Æ 0:05 for 5900 K \u3c TeA \u3c 6300 K. For the Li plateau stars (the cooler subset), the slope is smaller as the impact of the increasing surface convection zone affects the mixing, thus depleting more Li relative to Be. The different behavior in Be depletion for clusters of different ages is consistent with the idea of slow mixing related to rotation during the main-sequence phase of evolution. The range in metallicity in this sample of clusters is only 0.2 dex, so it is difficult to discern any influence of metallicity on the Li-Be relationship; however, the mean A(Be) in the cooler Hyades stars (with ½Fe=H¼þ0:13) is 1:35 Æ 0:02, which is higher than that for the Coma stars (with ½Fe=H¼ À0:09) of 1:26 Æ 0:02 by 0.09 dex

Magnetic Stress at the Marginally Stable Orbit: Altered Disk Structure, Radiation, and Black Hole Spin Evolution

Magnetic connections to the plunging region can exert stresses on the inner edge of an accretion disk around a black hole. We recompute the relativistic corrections to the thin-disk dynamics equations when these stresses take the form of a time-steady torque on the inner edge of the disk. The additional dissipation associated with these stresses is concentrated relatively close outside the marginally stable orbit, scaling as r to the -7/2 at large radius. As a result of these additional stresses: spin-up of the central black hole is retarded; the maximum spin-equilibrium accretion efficiency is 36%, and occurs at a/M=0.94; the disk spectrum is extended toward higher frequencies; line profiles (such as Fe K-alpha) are broadened if the line emissivity scales with local flux; limb-brightening, especially at the higher frequencies, is enhanced; and the returning radiation fraction is substantially increased, up to 58%. This last effect creates possible explanations for both synchronized continuum fluctuations in AGN, and polarization rises shortward of the Lyman edge in quasars. We show that no matter what additional stresses occur, when a/M < 0.36, the second law of black hole dynamics sets an absolute upper bound on the accretion efficiency.Comment: 11 pages, 15 figures, accepted for publication in the Astrophysical Journa

Design of the iLocater Acquisition Camera Demonstration System

Existing planet-finding spectrometers are limited by systematic errors that result from their seeing-limited design. Of particular concern is the use of multi-mode fibers (MMFs), which introduce modal noise and accept significant amounts of background radiation from the sky. We present the design of a single-mode fiber-based acquisition camera for a diffraction-limited spectrometer named "iLocater." By using the "extreme" adaptive optics (AO) system of the Large Binocular Telescope (LBT), iLocater will overcome the limitations that prevent Doppler instruments from reaching their full potential, allowing precise radial velocity (RV) measurements of terrestrial planets around nearby bright stars. The instrument presented in this paper, which we refer to as the acquisition camera "demonstration system," will measure on-sky single-mode fiber (SMF) coupling efficiency using one of the 8.4m primaries of the LBT in fall 2015