Insights into the chemical composition of the metal-poor Milky Way halo globular cluster NGC 6426

We present our detailed spectroscopic analysis of the chemical composition of four red giant stars in the halo globular cluster NGC 6426. We obtained high-resolution spectra using the Magellan2/MIKE spectrograph, from which we derived equivalent widths and subsequently computed abundances of 24 species of 22 chemical elements. For the purpose of measuring equivalent widths, we developed a new semi-automated tool, called EWCODE. We report a mean Fe content of [Fe/H] =−2.34 ± 0.05 dex (stat.) in accordance with previous studies. At a mean α-abundance of [(Mg, Si, Ca)/3 Fe] = 0.39 ± 0.03 dex, NGC 6426 falls on the trend drawn by the Milky Way halo and other globular clusters at comparably low metallicities. The distribution of the lighter α-elements as well as the enhanced ratio [Zn/Fe] = 0.39 dex could originate from hypernova enrichment of the pre-cluster medium. We find tentative evidence for a spread in the elements Mg, Si, and Zn, indicating an enrichment scenario, where ejecta of evolved massive stars of a slightly older population have polluted a newly born younger one. The heavy element abundances in this cluster fit well into the picture of metal-poor globular clusters, which in that respect appear to be remarkably homogeneous. The pattern of the neutron-capture elements heavier than Zn points toward an enrichment history governed by the r-process with little, if any, sign of s-process contributions. This finding is supported by the striking similarity of our program stars to the metal-poor field star HD 108317

Aminoterminales pro-natriuretisches Peptid zur Risikostratifizierung und Verlaufsbeurteilung von herzinsuffizienten Patienten mit kardialer Resynchronisationstherapie

Patienten mit einer schweren Herzinsuffizienz weisen eine hohe Mortalitätsrate auf. Auch wenn die Behandlung von Herzerkrankungen in den letzten Jahren stetig verbessert wurde, stellt bei der terminalen Herzinsuffizienz die Herztransplantation immer noch den Goldstandard dar. Dabei hat die Resynchronisationstherapie bei Patienten mit einer fortgeschrittenen Herzinsuffizienz und einer ventrikulären Asynchronie in den letzten Jahren an Bedeutung gewonnen. In dieser Studie wurden in der Zeit von 2002 bis 2006 60 Patienten mit einer chronischen Herzinsuffizienz und ventrikulärer Asynchronie untersucht, die einer biventrikulären Resynchronisationstherapie unterzogen wurden. Die Überlebensrate nach biventrikulärer ICD-Implantation betrug nach drei Jahren 95%. Der NT-proBNP Wert nahm von 2542 ± 2486 pg/ml präoperativ auf 1476 ± 1789 pg/ml ein Jahr nach Implantation eines CRT-Systems ab. Dabei konnte NT-proBNP als Marker der kardialen Regeneration nachgewiesen werden. Darüber hinaus ließ NT-proBNP als Marker präoperativ in gewissem Maße eine Prognose über den zu erwartenden Behandlungserfolg zu

Something borrowed, something blue:the nature of blue metal-poor stars inferred from their colours and chemical abundances

Blue metal-poor (BMP) stars are main sequence stars that appear bluer and more luminous than normal turnoff stars. They were originally singled out by using B−V and U−B colour cuts.Early studies found that a larger fraction of field BMP stars were binaries compared to normal halo stars. Thus, BMP stars are ideal field blue straggler candidates for investigating internal stellar evolution processes and binary interaction. In particular, the presence or depletion in lithium in their spectra is a powerful indicator of their origin. They are either old, halo blue stragglers experiencing internal mixing processes or mass transfer (Li-depletion), or intermediate-age, single stars of possibly extragalactic origin (2.2 dex halo plateau Li). However, we note that internal mixing processes can lead to an increased level of Li. Hence, this study combines photometry and spectroscopy to unveil the origin of various BMP stars. We first show how to separate binaries from young blue stars using photometry, metallicity and lithium. Using a sample of 80 BMP stars (T > 6300 K), we find that 97% of the BMP binaries have V−Ks0 < 1.08 ± 0.03, while BMP stars that are not binaries lie above this cut in two thirds of the cases. This cut can help classify stars that lack radial velocities from follow-up observations. We then trace the origin of two BMP stars from the photometric sample by conducting a full chemical analysis using new high-resolution and high signal-to-noise spectra. Based on their radial velocities, Li, α and s- and r-process abundances we show that BPS CS22874-042 is a single star (A(Li) = 2.38 ± 0.10 dex) while with A(Li)= 2.23 ± 0.07 dex CD-48 2445 is a binary, contrary to earlier findings. Our analysis emphasises that field blue stragglers can be segregated from single metal-poor stars, using (V−Ks) colours with a fraction of single stars polluting the binary sample, but not vice versa. These two groups can only be properly separated by using information from stellar spectra, illustrating the need for accurate and precise stellar parameters and high-resolution, high-S/N spectra in order to fully understand and classify this intriguing class of stars. Our high-resolution spectrum analysis confirms the findings from the colour cuts and shows that CS 22874−042 is single, while CD −48 2445 is most likely a binary. Moreover, the stellar abundances show that both stars formed in situ; CS 22874−042 carries traces of massive star enrichment and CD −48 2445 shows indications of AGB mass transfer mixed with gases ejected possibly from neutron star mergers

Bernoulli potential in type-I and weak type-II superconductors: I. Surface charge

The electrostatic potential close to the surface of superconductors in the Meissner state is discussed. We show that beside the Bernoulli potential, the quasiparticle screening, and the thermodynamic contribution due to Rickayzen, there is a non-local contribution which is large for both type-I and weak type-II superconductors.Comment: 7 pages, 4 figure

Non-critical, near extremal AdS_6 background as a holographic laboratory of four dimensional YM theory

We study certain properties of the low energy regime of a theory which resembles four dimensional YM theory in the framework of a non-critical holographic gravity dual. We use for the latter the near extremal $AdS_6$ non-critical SUGRA. We extract the glueball spectra that associates with the fluctuations of the dilaton, one form and the graviton and compare the results to those of the critical near extremal $D4$ model and lattice simulations. We show an area law behavior for the Wilson loop and screening for the 't Hooft loop. The Luscher term is found to be $-{3/24}\frac {\pi}{L}$. We derive the Regge trajectories of glueballs associated with the spinning folded string configurations.Comment: 25 pages, JHEP styl

Metastability and Transient Effects in Vortex Matter Near a Decoupling Transition

We examine metastable and transient effects both above and below the first-order decoupling line in a 3D simulation of magnetically interacting pancake vortices. We observe pronounced transient and history effects as well as supercooling and superheating between the 3D coupled, ordered and 2D decoupled, disordered phases. In the disordered supercooled state as a function of DC driving, reordering occurs through the formation of growing moving channels of the ordered phase. No channels form in the superheated region; instead the ordered state is homogeneously destroyed. When a sequence of current pulses is applied we observe memory effects. We find a ramp rate dependence of the V(I) curves on both sides of the decoupling transition. The critical current that we obtain depends on how the system is prepared.Comment: 10 pages, 15 postscript figures, version to appear in PR

Hemophagocytic lymphohistiocytosis and thrombotic microangiopathy after parvovirus B19 infection and renal transplantation: a case report

BACKGROUND: Hemophagocytic lymphohistiocytosis (HLH) is a rare and life-threatening disease characterized by hyperactivation of the immune system that causes hypercytokinemia and potentially multi organ failure. HLH can occur in patients with underlying rheumatic or autoinflammatory disorders. Additionally, HLH can develop in patients during infections or malignancies without a known genetic predisposition. CASE PRESENTATION: We herein report a patient, who presented with fever, both acute kidney and liver injury, anemia, thrombocytopenia and HSV stomatitis. HLH was diagnosed based on clinical criteria and qPCR revealed an acute parvovirus B19 infection as potential underlying infectious trigger. Treatment was started with both IVIG and dexamethasone. Subsequently, kidney biopsy demonstrated TMA. CONCLUSIONS: In rare cases both HLH and aHUS can occur simultaneously in a patient as a consequence of viral infections. Insights from this unusual case might help physicians understand this complex symptom constellation

Association between the oxytocin receptor (OXTR) gene and mesolimbic responses to rewards

10.1186/2040-2392-5-7Molecular Autism51

Comparison of the Effects of Two Topical Fluoride Regimens on Demineralized Enamel in vivo

The purpose of this investigation was to study the intra-oral remineralization of acid-softened enamel by a NaF dentifrice compared with that from a combination of topical F agents. Bovine enamel slabs were demineralized with 0.1 mol/L lactic acid at pH 4.0 for 14 hr and then mounted in a removable mandibular appliance. Control slabs were worn for 96 hr by seven adult males who brushed daily with a F-free dentifrice. Test slabs were brushed with a NaF dentifrice 4 x / day or with the same dentifrice 4 x /day and a 0.02% APF mouthrinse and a 0.4% SnF2 gel which were applied oncelday for three days. The natural dentition was also brushed with the NaF dentifrice during both test periods. Microhardness testing was performed on sound enamel, and after acid-softening, intra-oral exposure (IOE), and acid resistance testing (ART) in 0.01 mol/L lactic acid at pH 4.0 for 24 hr. Control and test slabs were etched with 0.5 mol/L HClO4 for from 15 to 60 sec. The F content was measured with a F electrode and PO4 by spectrophotometry. Contact microradiography and image analyses were performed on control and test slabs so that changes in mineral content resulting from treatment could be assessed. Both test groups were significantly harder after both IOE and ART than were controls, but no differences appeared between the effects of the two test groups. The F content of control slabs was significantly less than that of both test groups, and the combination-treated slabs showed greater F than did the dentifrice-treated slabs. Microradiographs revealed a higher mineral content in the basal 2/3 of combination-treated lesions, while diffuse mineral deposition occurred, especially subjacent to the surface in the dentifrice-treated lesions. Control lesions showed little added mineral.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66793/2/10.1177_00220345880670061301.pd