Simultaneous Doppler maps of IP Peg in outburst

IP Pegasi is an eclipsing dwarf nova lying above the period gap with an orbital period of 3.8h. It is the first cataclysmic variable to show evidence of spiral arms in its accretion disc. We present new time-resolved echelle spectroscopic observations of IP Peg, covering the 3900-7700 Angstrom range. This allows us to produce simultaneous Doppler Maps in 9 emission lines

IP Pegasi in outburst: Echelle spectroscopy & Modulation Doppler Tomography

We analyse a unique set of time-resolved echelle spectra of the dwarf nova IP Peg, obtained at ESO's NTT with EMMI. The dataset covers the wavelength range of 4000-7500A and shows Balmer, HeI, HeII and heavier elements in emission. IP Peg was observed one day after the peak of an outburst. The trailed spectra, spectrograms and Doppler maps show characteristics typical of IP Pegasi during the early stages of its outburst. The high-ionisation line of HeII 4686A is the most centrally located line and has the greatest radial extension compared to the HeI lines. The Balmer lines extend from close to the white dwarf up to approximately 0.45 times R_L, with the outer radius gradually increasing when moving from H delta to H alpha. The application, for the first time, of the modulation Doppler tomography technique, maps any harmonically varying components present in the system configuration. We find, as expected, that part of the strong secondary star emission in Balmer and HeI lines is modulated predominantly with the cosine term, consistent with the emission originating from the irradiated front side of the mass-donor star, facing the accreting white dwarf. For the Balmer lines the level of the modulation, compared to the average emission, decreases when moving to higher series. Emission from the extended accretion disk appears to be only weakly modulated, with amplitudes of at most a few percent of the non-varying disk emission. We find no evidence of modulated emission in the spiral arms, which if present, is relatively weak at that our signal-to-noise ratio was good enough to put a lower detection limit of any modulated emission at 5--6%. Only in one arm of the HeII 4686A line, is there a possibility of modulated emission, but again, we cannot be sure this is not caused by blending with the nearby Bowen complex of lines.Comment: 20 pages, 8 figures, submitted to Journal of Astronomical Dat

Photometric study of selected cataclysmic variables II. Time-series photometry of nine systems

We present time-series photometry of nine cataclysmic variables: EI UMa, V844Her, V751 Cyg, V516 Cyg, GZ Cnc, TY Psc, V1315 Aql, ASAS J002511+1217.12, V1315 Aql and LN UMa. The observations were conducted at various observatories, covering 170 hours and comprising 7,850 data points in total. For the majority of targets we confirm previously reported periodicities and for some of them we give, for the first time, their spectroscopic orbital periods. For those dwarf-nova systems which we observed during both quiescence and outburst, the increase in brightness was followed by a decrease in the amount of flickering. Quasi-periodic oscillations have either been discovered, or were confirmed. For the eclipsing system V1315 Aql we have covered 9 eclipses, and obtained a refined orbital ephemeris. We find that, during its long baseline of observations, no change in the orbital period of this system has occurred. V1315 Aql also shows eclipses of variable depth.Comment: 30 pages, 16 figures, 4 tables. Submitted to JA

RR Pictoris: an old nova showing superhumps and QPOs

We present time-resolved V-photometry of the old nova RR Pic. Apart from the hump-like variability, the light curves show the strong flickering and random variation typical for RR Pic. We do not find any convincing evidence for the previously reported eclipse. The extrapolated eclipse phase coincides with a broad minimum, but comparing the overall shape of the light curve suggests that the eclipse should actually be located around phase 0.2. The orbital period which we derive from these data agrees well with the old one, any uncertainty is too small to account for the possible phase shift. Apart from the 3.48h period, which is usually interpreted as the orbital one, we find an additional period at P=3.78h, which we interpret as the superhump period of the system; the corresponding precession period at 1.79d is also present in the data. We also find indications for the presence of a 13min quasi-periodic oscillation.Comment: 9 pages, 7 figures + 1 Appendix figure, accepted by MNRA

Spawning induction of first-generation (F1) greater amberjack Seriola dumerili in the Canary Islands, Spain using GnRHa delivery systems

The development of a sustainable aquaculture industry requires the closing of the life-cycle of a potential species in captivity, and the establishment of breeding selection programs using hatchery-produced breeding stocks. The greater amberjack Seriola dumerili is a cosmopolitan pelagic species that has been considered as a good candidate for the species diversification of aquaculture production in the Mediterranean region. However, commercial production is still very limited due to bottlenecks in reproduction, larval rearing and management control during grow out. The aim of the present study was to examine the reproductive development of hatchery-produced greater amberjack and to develop a spawning induction protocol based on the use of gonadotropin releasing hormone agonist (GnRHa) in a controlled-release delivery system. The results showed that hatchery-produced greater amberjack undergo normal gametogenesis and can be induced to undergo maturation, ovulation and spawning after multiple administrations of GnRHa implants, over an extended spawning period lasting from May to September in the Canary Islands, Spain. The use of GnRHa-delivery systems resulted in multiple spawns of fertilized and viable eggs. Egg production was high and egg quality adequate for the implementation of larval rearing for commercial purposes. The handling required to administer the GnRHa implants during the prolonged spawning season did not result in any negative effect on the welfare and reproductive performance of the fish based on evaluation of several biochemical parameters. The developed reproduction control method shows great potential to advance the commercial production of greater amberjack, by enabling the use of hatchery-produced broodstocks for further breeding selection.Postprin

Unsung heroes: who supports social work students on placement?

Since the introduction of the three year degree programme in 2003, social work education has undergone a number of significant changes. The time students spend on placement has been increased to two hundred days, and the range of placement opportunities and the way in which these placements have been configured has significantly diversified. A consistent feature over the years, however, has been the presence of a Practice Educator (PE) who has guided, assessed and taught the student whilst on placement. Unsurprisingly, the role of the PE and the pivotal relationship they have with the student has been explored in the past and features in social work literature. This paper, however, concentrates on a range of other relationships which are of significance in providing support to students on placement. In particular it draws on research to discuss the role of the university contact tutor, the place of the wider team in which the student is sited, and the support offered by family, friends and others. Placements and the work undertaken by PE’s will continue to be integral to the delivery of social work education. It is, however, essential to recognise and value the often over looked role of others in providing support to students on placement