A simple, accurate depth check guage

Easily made, pen-light battery operated production check gauge has probe-activated switch with fail-safe features to insure proper operation. Parts can be reliably and quickly checked. Gauge is equipped with tolerance band adjustment and can use interchangeable probes for different applications. Accompanying tester permits frequent check of calibration

Resonant Relaxation in Stellar Systems

We demonstrate the existence of an enhanced rate of angular momentum relaxation in nearly Keplerian star clusters, such as those found in the centers of galactic nuclei containing massive black holes. The enhanced relaxation arises because the radial and azimuthal orbital frequencies in a Keplerian potential are equal, and hence may be termed {\em resonant relaxation}. We explore the dynamics of resonant relaxation using both numerical simulations and order-of-magnitude analytic calculations. We find that the resonant angular momentum relaxation time is shorter than the non-resonant relaxation time by of order $M_\star/M$, where $M_\star$ is the mass in stars and $M$ is the mass of the central object. Resonance does not enhance the energy relaxation rate. We examine the effect of resonant relaxation on the rate of tidal disruption of stars by the central mass; we find that the flux of stars into the loss cone is enhanced when the loss cone is empty, but that the disruption rate averaged over the entire cluster is not strongly affected. We show that relativistic precession can disable resonant relaxation near the main-sequence loss cone for black hole masses comparable to those in galactic nuclei. Resonant dynamical friction leads to growth or decay of the eccentricity of the orbit of a massive body, depending on whether the distribution function of the stars is predominantly radial or tangential. The accelerated relaxation implies that there are regions in nuclear star clusters that are relaxed in angular momentum but not in energy; unfortunately, these regions are not well-resolved in nearby galaxies by the Hubble Space Telescope.Comment: 34 pages (LaTeX2e format), 2 PostScript figures, uses epsf.sty and aaspp4.sty (AASTeX v4.0), submitted to New Astronom

Stationary problems for equation of the KdV type and dynamical rr-matrices.

We study a quite general family of dynamical $r$-matrices for an auxiliary loop algebra ${\cal L}({su(2)})$ related to restricted flows for equations of the KdV type. This underlying $r$-matrix structure allows to reconstruct Lax representations and to find variables of separation for a wide set of the integrable natural Hamiltonian systems. As an example, we discuss the Henon-Heiles system and a quartic system of two degrees of freedom in detail.Comment: 25pp, LaTe

Development of a nucleic acid lateral flow immunoassay for simultaneous detection of Listeria spp. and Listeriamonocytogenes in food

We present a new nucleic acid lateral flow immunoassay (NALFIA) for the assessment of listeria contamination. The detection procedure starts with enrichment of sample in Half Fraser broth (24 h). Following isolation of DNA, a duplex PCR is performed with two labelled primer sets, one generic and directed to a specific sequence of the gene encoding 16S rRNA from Listeria spp. and the other specific and directed to a part of the prfA gene encoding the central virulence gene regulator from the food pathogen Listeria monocytogenes (3.5 h). The PCR solution is directly added to the one-step assay device and the appearance of a grey/black line is indicative of the presence of specific amplicons (max 15 min). In all tests performed, the method correctly identified L. monocytogenes and strains of Listeria spp. PCR material of over 20 food samples was tested by NALFIA. The method proved to be useful for the detection of L. monocytogenes in different kinds of food sample

Stellar laboratories III. New Ba V, Ba VI, and Ba VII oscillator strengths and the barium abundance in the hot white dwarfs G191-B2B and RE0503-289

For the spectral analysis of high-resolution and high-signal-to-noise (S/N) spectra of hot stars, state-of-the-art non-local thermodynamic equilibrium (NLTE) model atmospheres are mandatory. These are strongly dependent on the reliability of the atomic data that is used for their calculation. Reliable Ba V - VII oscillator strengths are used to identify Ba lines in the spectra of the DA-type white dwarf G191-B2B and the DO-type white dwarf RE0503-289 and to determine their photospheric Ba abundances. We newly calculated Ba V - VII oscillator strengths to consider their radiative and collisional bound-bound transitions in detail in our NLTE stellar-atmosphere models for the analysis of Ba lines exhibited in high-resolution and high-S/N UV observations of G191-B2B and RE0503-289. For the first time, we identified highly ionized Ba in the spectra of hot white dwarfs. We detected Ba VI and Ba VII lines in the Far Ultraviolet Spectroscopic Explorer (FUSE) spectrum of RE0503-289. The Ba VI / Ba VII ionization equilibrium is well reproduced with the previously determined effective temperature of 70000 K and surface gravity of $\log g = 7.5$. The Ba abundance is $3.5 \pm 0.5 \times 10^{-4}$ (mass fraction, about 23000 times the solar value). In the FUSE spectrum of G191-B2B, we identified the strongest Ba VII line (at 993.41 \AA) only, and determined a Ba abundance of $4.0 \pm 0.5 \times 10^{-6}$ (about 265 times solar). Reliable measurements and calculations of atomic data are a pre-requisite for stellar-atmosphere modeling. Observed Ba VI - VII line profiles in two white dwarfs' (G191-B2B and RE0503-289) far-ultraviolet spectra were well reproduced with our newly calculated oscillator strengths. This allowed to determine the photospheric Ba abundance of these two stars precisely.Comment: 36 pages, 8 figure

It's the market power, stupid! Stock return patterns in international bank M&A

This paper analyzes capital market reactions to international bank M&A. We investigate combined stock return patterns of targets, bidders, and their peers upon takeover announcement, and closing or withdrawal. We distinguish five common M&A hypotheses and relate characteristic and mutually exclusive abnormal stock return patterns to each hypothesis. We find that investors believe in gains through the exploitation of market power by the post-merger entity. In a multinomial logistic model we show that patterns related to market power significantly concur with large relative target size, intra-industry mergers, and increasing market concentration, suggesting a substantial lessening of competition through M&A. --M&A,Banks,Event Study,Peer Returns,Market Power

Gravitational Collapse of Small-Scale Structure as the Origin of the Lyman Alpha Forest

If gravitational clustering is a hierarchical process, the present large-scale structure of the galaxy distribution implies that structures on smaller scales must have formed at high redshift. We simulate the formation of small-scale structure (average cell mass: $\Delta \bar m_b=10^{4.2}$M$_\odot$) and the evolution of photoionized gas, in the specific case of a CDM model with a cosmological constant. The photoionized gas has a natural minimal scale of collapse, the Jeans scale ($m_{b,J}\simeq 10^{9}$M$_\odot$). We find that low column density (\nhi \le 10^{14}\cm^{-2}) lines originate in regions resembling Zel'dovich pancakes, where gas with overdensities in the range $3 - 30$ is enclosed by two shocks but is typically re-expanding at approximately the Hubble velocity. However, higher column density (\nhi \ge 10^{15}\cm^{-2}) lines stem from more overdense regions where the shocked gas is cooling. We show that this model can probably account for the observed number of lines, their distribution in column density and b-parameters, as well as the cloud physical sizes as observed in gravitationally lensed quasars. We find a redshift evolution that isComment: 15p postscript file to appear in The Astrophysical Journal Letters (1994

Stellar laboratories. V. The Xe VI ultraviolet spectrum and the xenon abundance in the hot DO-type white dwarf RE0503-289

For the spectral analysis of spectra of hot stars with a high resolution and high signal-to-noise ratio (S/N), advanced non-local thermodynamic equilibrium (NLTE) model atmospheres are mandatory. These are strongly dependent on the reliability of the atomic data that are used for their calculation. Reliable Xe VI oscillator strengths are used to identify Xe lines in the ultraviolet spectrum of the DO-type white dwarf RE0503-289 and to determine its photospheric Xe abundance. We publish newly calculated oscillator strengths that are based on a recently measured Xe VI laboratory line spectrum. These strengths were used to consider their radiative and collisional bound-bound transitions in detail in our NLTE stellar-atmosphere models to analyze Xe VI lines exhibited in high-resolution and high S/N UV observations of RE0503-289. We identify three hitherto unknown Xe VI lines in the ultraviolet spectrum of RE0503-289 and confirm the previously measured photospheric Xe abundance of this white dwarf (log Xe = -4.2 +/- 0.6). Reliable measurements and calculations of atomic data are prerequisite for stellar-atmosphere modeling. Observed Xe VI line profiles in the ultraviolet spectrum of the white dwarf RE0503-289 were well reproduced with the newly calculated Xe VI oscillator strengths.Comment: 3 pages, 4 figure

High-velocity gas towards the LMC resides in the Milky Way halo

To explore the origin of high-velocity gas in the direction of the Large Magellanic Cloud (LMC) we analyze absorption lines in the ultraviolet spectrum of a Galactic halo star that is located in front of the LMC at d=9.2 kpc distance. We study the velocity-component structure of low and intermediate metal ions in the spectrum of RXJ0439.8-6809, as obtained with the Cosmic Origins Spectrograph (COS) onboard HST, and measure equivalent widths and column densities for these ions. We supplement our COS data with a Far-Ultraviolet Spectroscopic Explorer spectrum of the nearby LMC star Sk-69 59 and with HI 21cm data from the Leiden-Argentina-Bonn (LAB) survey. Metal absorption towards RXJ0439.8-6809 is unambiguously detected in three different velocity components near v_LSR=0,+60, and +150 km/s. The presence of absorption proves that all three gas components are situated in front of the star, thus being located in the disk and inner halo of the Milky Way. For the high-velocity cloud (HVC) at v_LSR=+150 km/s we derive an oxygen abundance of [O/H]=-0.63 (~0.2 solar) from the neighbouring Sk-69 59 sightline, in accordance with previous abundance measurements for this HVC. From the observed kinematics we infer that the HVC hardly participates in the Galactic rotation. Our study shows that the HVC towards the LMC represents a Milky Way halo cloud that traces low-column density gas with relatively low metallicity. It rules out scenarios in which the HVC represents material close to the LMC that stems from a LMC outflow.Comment: 4 pages, 3 figures; submitted to A&A Letter

High-precision Atomic Physics Laboratories in Space: White Dwarfs and Subdwarfs

The 21st European Workshop on White Dwarfs was held in Austin, TX from July 23rd to 27th of 2018Stellar atmospheres are prime laboratories to determine atomic properties of highly ionized species. Reliable opacities are crucial ingredients for the calculation of stellar atmospheres of white dwarfs and subdwarfs. A detailed investigation on the precision of many iron-group oscillator strengths is still outstanding. To make progress, we used the Hubble Space Telescope Imaging Spectrograph to measure high-resolution spectra of three hot subdwarfs that exhibit extremely high iron-group abundances. The predicted relative strengths of the identified lines are compared with the observations to judge the quality of Kurucz’s line data and to determine correction factors for abundance determinations of the respective elements.Astronom