Transient jets in V617 Sagittarii

Some of the luminous Compact Binary Supersoft X-Ray sources (CBSS) have shown indications of jets, also called satellites due to their appearance in the spectra. In V Sagittae (V Sge) stars, the galactic counterparts of the CBSS, such features have been reported only for WX Cen. If V Sge stars are indeed the analogs of CBSS, one may expect transient jet emission in other objects of this class. Spectroscopic observations of the V Sge star V617 Sgr have been made, both at high photometric state and at decline. We show that V617 Sgr presents Halpha satellites at high photometric state with velocities of +/-780 km/s. This feature confirms, once more, the CBSS nature of the V Sge stars, however the details of the spectral characteristics also suggest that the two groups of stars display some intrinsic spectroscopic differences, which are likely to be due to a selection effect related to chemical abundance.Comment: Four pages, accepted to be published as a Letter in A&

Ein neuer Genort für eine autosomal-dominante, nichtsyndromale Schwerhörigkeit (DFNA33) liegt auf Chromosom 13q34-qte

Bei der Untersuchung einer deutschen Familie mit nichtsyndromalem Hörverlust mit frühem Beginn und autosomal-dominantem Erbgang konnten wir eine Kopplung zu bekannten DFNA-Loci ausschließen und die Existenz eines neuen Locus (DFNA33) bestätigen. Mit einem nachfolgenden Genom-Scan wurde der Phänotyp auf einem 6-cM-Intervall auf Chromosom 13q34-qter kartiert. Für den Marker D13S285 wurde ein maximaler 2-Punkt-Lodscore von 2,96 erreicht, der maximale Lodscore in der Multipoint-Analyse betrug 3,28 bei 124,56 cM. = By investigation of a German family pedigree with non-syndromic hearing impairment of early onset and autosomal-dominant mode of inheritance, linkage to known DFNA loci was excluded, and the existence of a new locus (DFNA33) was revealed. In a subsequent genomic scan the phenotype was mapped to a 6 cM interval on chromosome 13q34-qter. A maximum two-point lod score of 2.96 was obtained for the marker D13S285 with a maximum lod score in the multipoint analysis of 3.28 at 124.56 cM

Determination of Total Homocysteine in Human Plasma by Isocratic High-Performance Liquid Chromatography

Peer Reviewe

Simultaneous solution of Kompaneets equation and Radiative Transfer equation in the photon energy range 1 - 125 KeV

Radiative transfer equation in plane parallel geometry and Kompaneets equation is solved simultaneously to obtain theoretical spectrum of 1-125 KeV photon energy range. Diffuse radiation field is calculated using time-independent radiative transfer equation in plane parallel geometry, which is developed using discrete space theory (DST) of radiative transfer in a homogeneous medium for different optical depths. We assumed free-free emission and absorption and emission due to electron gas to be operating in the medium. The three terms $n, n^2$ and $\displaystyle \bigg({\frac {\partial n}{\partial x_k}}\bigg)$ where $n$ is photon phase density and $\displaystyle x_k= \bigg({\frac {h \nu} {k T_e}} \bigg)$, in Kompaneets equation and those due to free-free emission are utilized to calculate the change in the photon phase density in a hot electron gas. Two types of incident radiation are considered: (1) isotropic radiation with the modified black body radiation $I^{MB}$ [1] and (2) anisotropic radiation which is angle dependent. The emergent radiation at $\tau=0$ and reflected radiation $\tau=\tau_{max}$ are calculated by using the diffuse radiation from the medium. The emergent and reflected radiation contain the free-free emission and emission from the hot electron gas. Kompaneets equation gives the changes in photon phase densities in different types of media. Although the initial spectrum is angle dependent, the Kompaneets equation gives a spectrum which is angle independent after several Compton scattering times.Comment: 31 pages, 8 figures, Accepte

The Contribution of Particle Impact to the Production of Fe K Emission from Accreting Black Holes

The iron K line is perhaps the most important spectral diagnostic available in the study of accreting black holes. The line is thought to result from the reprocessing of external X-rays by the surface of the accretion disk. However, as is observed in the solar corona, illumination by energetic particles may also produce line emission. In principle, such a process may be uncorrelated with the observed X-rays and could explain some of the unexpected variability behavior of the Fe line. This paper compares predictions of iron K flux generated by impacting electrons and protons to that from photoionization. Non-thermal power-laws of electrons are considered as well as thermal distributions of electrons and virialized protons. The electrons are thought to originate in a magnetically dominated accretion disk corona, while the protons are considered in the context of a two phase (hot/cold) accretion scenario. In each case, the Fe K flux from particle impact is found to be < 1% of that produced by photoionization by a hard X-ray power-law (normalized to the same energy flux as the particles). Thus, the electrons or protons must strike the disk with 100--10,000 times more energy flux than radiation for particle impact to be a significant producer of Fe K flux. This situation is difficult to reconcile with the observations of hard X-ray spectra, or the proposed particle acceleration mechanisms in the accretion disk corona. Truncated accretion flows must be externally illuminated by hard X-rays in order to produce the Fe line, as proton impact is very inefficient in generating line emission. In contrast to the Sun, our conclusion is that, with the possible exception for localized regions around magnetic footpoints, particle impact will not be an important contributor to the X-ray emission in accreting black holes.Comment: 27 pages, 6 figures, ApJ accepte

EVLA Observations Constrain the Environment and Progenitor System of Type Ia Supernova 2011fe

We report unique EVLA observations of SN 2011fe representing the most sensitive radio study of a Type Ia supernova to date. Our data place direct constraints on the density of the surrounding medium at radii ~10^15-10^16 cm, implying an upper limit on the mass loss rate from the progenitor system of Mdot <~ 6 x 10^-10 Msol/yr (assuming a wind speed of 100 km/s), or expansion into a uniform medium with density n_CSM <~ 6 cm^-3. Drawing from the observed properties of non-conservative mass transfer among accreting white dwarfs, we use these limits on the density of the immediate environs to exclude a phase space of possible progenitors systems for SN 2011fe. We rule out a symbiotic progenitor system and also a system characterized by high accretion rate onto the white dwarf that is expected to give rise to optically-thick accretion winds. Assuming that a small fraction, 1%, of the mass accreted is lost from the progenitor system, we also eliminate much of the potential progenitor parameter space for white dwarfs hosting recurrent novae or undergoing stable nuclear burning. Therefore, we rule out the most popular single degenerate progenitor models for SN 2011fe, leaving a limited phase space inhabited by some double degenerate systems and exotic progenitor scenarios.Comment: Accepted to Ap

Potential role of levocarnitine supplementation for the treatment of chemotherapy-induced fatigue in non-anaemic cancer patients

Ifosfamide and cisplatin cause urinary loss of carnitine, which is a fundamental molecule for energy production in mammalian cells. We investigated whether restoration of the carnitine pool might improve chemotherapy-induced fatigue in non-anaemic cancer patients. Consecutive patients with low plasma carnitine levels who experienced fatigue during chemotherapy were considered eligible for study entry. Patients were excluded if they had anaemia or other conditions thought to be causing asthenia. Fatigue was assessed by the Functional Assessment of Cancer Therapy-Fatigue quality of life questionnaire. Treatment consisted of oral levocarnitine 4 g daily, for 7 days. Fifty patients were enrolled; chemotherapy was cisplatin-based in 44 patients and ifosfamide-based in six patients. In the whole group, baseline mean Functional Assessment of Cancer Therapy-Fatigue score was 19.7 (±6.4; standard deviation) and the mean plasma carnitine value was 20.9 μM (±6.8; standard deviation). After 1 week, fatigue ameliorated in 45 patients and the mean Functional Assessment of Cancer Therapy-Fatigue score was 34.9 (±5.4; standard deviation) (P<.001). All patients achieved normal plasma carnitine levels. Patients maintained the improved Functional Assessment of Cancer Therapy-Fatigue score until the next cycle of chemotherapy. In selected patients, levocarnitine supplementation may be effective in alleviating chemotherapy-induced fatigue. This compound deserves further investigations in a randomised, placebo-controlled study

A search for radio emission from Galactic supersoft X-ray sources

We have made a deep search for radio emission from all the northern hemisphere supersoft X-ray sources using the VLA and MERLIN telescopes, at 5 and 8.4 GHz. Three previously undetected sources: T Pyx, V1974 Cygni and RX J0019.8+2156 were imaged in quiescence using the VLA in order to search for any persistent emission. No radio emission was detected in any of the VLA fields down to a typical 1 sigma RMS noise of 20 uJy/beam, however, 17 new point sources were detected in the fields with 5 GHz fluxes between 100 and 1500 uJy giving an average 100 uJy-source density of around 200 per square degree, comparable to what was found in the MERLIN HDF survey. The persistent source AG Draconis was observed by MERLIN to provide a confirmation of previous VLA observations and to investigate the source at a higher resolution. The core is resolved at the milliarcsec scale into two components which have a combined flux of around 1 mJy. It is possible that we are detecting nebulosity which is becoming resolved out by the higher MERLIN resolution. We have investigated possible causes of radio emission from a wind environment, both directly from the secondary star, and also as a consequence of the high X-ray luminosity from the white dwarf. There is an order of magnitude discrepancy between observed and modelled values which can be explained by the uncertainty in fundamental quantities within these systems.Comment: Accepted for publication in MNRAS, 7 pages, 1 figur

Circumbinary disks and cataclysmic variable evolution

The influence of a circumbinary (CB) disk on the evolution of cataclysmic variable (CV) binary systems is investigated. We show that CB mass surface densities sufficient to influence the evolution rate are plausibly provided by the outflows observed in CVs, if the net effect of these winds is to deliver $10^{-4}$--$10^{-3}$ of the mass transfer rate to the CB disk. The torque exerted by the CB disk provides a positive feedback between mass transfer rate and CB disk mass which can lead to mass transfer rates of \sim 10^{-8} -10^{-7} \mpy. This mechanism may be responsible for causing the range of variation of mass transfer rates in CV's. In particular, it may explain rates inferred for the novalike variables and the supersoft X-ray binary systems observed near the upper edge of the period gap ($P \sim 3 - 4$ hr), as well as the spread in mass transfer rates above and below the period gap. Consquences and the possible observability of such disks are discussed.Comment: submitted to Ap