VSOP observation of the quasar PKS 2215+020: a new laboratory for core-jet physics at z=3.572

We report results of a VSOP (VLBI Space Observatory Programme) observation of a high redshift quasar PKS 2215+020 (z=3.572). The ~1 milliarcsecond resolution image of the quasar reveals a prominent `core-jet' structure on linear scales from 5/h to 300/h pc ($H_0=100*h km/(s*Mpc). The brightness temperatures and sizes of bright features identified in the jet are consistent with emission from relativistic shocks dominated by adiabatic energy losses. The jet is powered by the central black hole with estimated mass of ~4*10^9 solar masses. Comparisons with VLA and ROSAT observations indicate a possible presence of an extended radio/X-ray halo surrounding 2215+020.Comment: 15 pages, 6 figures, aastex macros; accepted for publication in The Astrophysical Journal, V.546, N.2 *(January 10 2001

The Radio Quiescence of Active Galaxies with High Accretion Rates

We present 6 cm Very Large Array observations of the Greene & Ho (2004) sample of 19 low-mass active galaxies with high accretion rates. This is one of the only studies of a uniform sample of narrow-line Seyfert 1 (NLS1) galaxies with such high sensitivity and resolution. Although we detect only one source, the entire sample is very radio-quiet down to strong limits. GH10 was found to have a radio power of 8.5 x 10^21 W/Hz, and a ratio R = f(6 cm)/f(4400 A) of 2.8. The 3 sigma upper limits for the remaining nondetections correspond to radio powers from 3 x 10^20 to 8 x 10^21 W/Hz and 0.47 < R <9.9. Stacking all nondetections yields an even stronger upper limit of R < 0.27. An assessment of existing observations in the literature confirms our finding that NLS1s are consistently radio-quiet, with a radio-loud fraction of 0%-6%, which is significantly lower than the 10%-20% observed in the general quasar population. By analogy with stellar-mass black holes, we argue that AGNs undergo a state transition at L_bol/L_Edd~0.01. Below this value a radiatively inefficient accretion flow effectively drives an outflow, which disappears when the flow turns into an optically thick, geometrically thin disk, or a radiation pressure-dominated slim disk at still higher L_bol/L_Edd.Comment: To appear in ApJ; 8 pages, 3 figures; uses emulateapj5.st

In-Air Evoked Potential Audiometry of Grey Seals (Halichoerus grypus) from the North and Baltic Seas

In-air anthropogenic sound has the potential to affect grey seal (Halichoerus grypus) behaviour and interfere with acoustic communication. In this study, a new method was used to deliver acoustic signals to grey seals as part of an in-air hearing assessment. Using in-ear headphones with adapted ear inserts allowed for the measurement of auditory brainstem responses (ABR) on sedated grey seals exposed to 5-cycle (2-1-2) tone pips. Thresholds were measured at 10 frequencies between 1–20 kHz. Measurements were made using subcutaneous electrodes on wild seals from the Baltic and North Seas. Thresholds were determined by both visual and statistical approaches (single point F-test) and good agreement was obtained between the results using both methods. The mean auditory thresholds were ≤40 dB re 20 µPa peak equivalent sound pressure level (peSPL) between 4–20 kHz and showed similar patterns to in-air behavioural hearing tests of other phocid seals between 3 and 20 kHz. Below 3 kHz, a steep reduction in hearing sensitivity was observed, which differed from the rate of decline in sensitivity obtained in behavioural studies on other phocids. Differences in the rate of decline may reflect influence of the ear inserts on the ability to reliably transmit lower frequencies or interference from the structure of the distal end of the ear canal

The properties of the local spiral arms from RAVE data: two-dimensional density wave approach

Using the RAVE survey, we recently brought to light a gradient in the mean galactocentric radial velocity of stars in the extended solar neighbourhood. This gradient likely originates from non-axisymmetric perturbations of the potential, among which a perturbation by spiral arms is a possible explanation. Here, we apply the traditional density wave theory and analytically model the radial component of the two-dimensional velocity field. Provided that the radial velocity gradient is caused by relatively long-lived spiral arms that can affect stars substantially above the plane, this analytic model provides new independent estimates for the parameters of the Milky Way spiral structure. Our analysis favours a two-armed perturbation with the Sun close to the inner ultra-harmonic 4:1 resonance, with a pattern speed \Omega_p=18.6^{+0.3}_{-0.2} km/s/kpc and a small amplitude A=0.55 \pm 0.02% of the background potential (14% of the background density). This model can serve as a basis for numerical simulations in three dimensions, additionally including a possible influence of the galactic bar and/or other non-axisymmetric modes.Comment: 9 pages, 4 figures, accepted for publication in MNRA

Radio-loud Active Galaxies in the Northern ROSAT All-Sky Survey III: New Spectroscopic Identifications from the RGB BL Lac Survey

We present new spectroscopic identifications for 169 objects in the RASS-Green Bank (RGB) catalog of radio- and X-ray-emitting AGN. These data significantly increase the fraction of bright RGB objects with classifications. Specifically, we report and discuss the classification of 66 radio-loud quasars, 53 BL Lacs, 33 Broad Line Radio Galaxies, 5 Narrow Line Radio Galaxies, 1 Seyfert I galaxy and 11 galaxies or galaxies in clusters. Over 78% of the identifications we present here are new. The observations we report were undertaken as part of our targeted search program to identify a new, large unbiased sample of BL Lac Objects and we therefore discuss the BL Lac sample extensively. Unlike many previous surveys, we impose no selection criteria based on optical morphology, color or broadband spectral energy distribution. Our classifications are based solely on a carefully defined set of self-consistent spectroscopic classification criteria. We show the 53 RGB presented here exhibit transitional properties between normal galaxies and BL Lacs discovered previously. We show there is no clear separation in CaII break strength between RGB BL Lacs and galaxies, with the distribution of break strengths varying smoothly between 0% and 50%. We also show that the newly discovered RGB BL Lacs reside in a "zone of avoidance" in the log(S_x/S_r) vs. log(S_o/S_r) diagram. This has important implications for BL Lac search strategies since it shows that RASS BL Lac samples will be severely incomplete if candidates are chosen only from among those objects with the highest S_x/S_r flux ratios.Comment: 21 pages text, 189 Figures, 4 tables, LaTeX2E, 4.2MB tar file (compressed); special style file paper.sty provide

Emerging and recurring diseases in cetaceans worldwide and the role of environmental stressors. Scientific Committee Document SC/60/DW5, International Whaling Commission, June 2008, Santiago, Chile

Emerging and recurring infectious diseases known or suspected to have the potential to significantly impact cetacean populations, and possible synergistic effects of environmental factors are reviewed. Cetacean morbilliviruses and papillomaviruses and brucellosis may affect population densities through high mortality rates or interference with reproduction. Evidence is available for the role of environmental factors in the emergence/recurrence and severity of at least six infectious conditions i.e. lobomycosis, toxoplasmosis, tattoo skin disease, generalized bacterial infections, miscellaneous skin diseases and morbillivirus epizootics. Other micro-parasites of potential importance include rhabdo-, herpes- and parainfluenza-viruses as well as Helicobacter spp., Streptococcus spp., Salmonella spp. and Mycobacterium marinum. The population impact and aetiology of newly emerging skin diseases in South America are unknown and represent a cause of concern

Detection and discrimination of herpes simplex viruses, haemophilus ducreyi, treponema pallidum, and calymmatobacterium (klebsiella) granulomatis from genital ulcers

Background. Genital ulcer disease (GUD) is commonly caused by pathogens for which suitable therapies exist, but clinical and laboratory diagnoses may be problematic. This collaborative project was undertaken to address the need for a rapid, economical, and sensitive approach to the detection and diagnosis of GUD using noninvasive techniques to sample genital ulcers. Methods. The genital ulcer disease multiplex polymerase chain reaction (GUMP) was developed as an inhouse nucleic acid amplification technique targeting serious causes of GUD, namely, herpes simplex viruses (HSVs), Haemophilus ducreyi, Treponema pallidum, and Klebsiella species. In addition, the GUMP assay included an endogenous internal control. Amplification products from GUMP were detected by enzyme linked amplicon hybridization assay (ELAHA). Results. GUMP-ELAHA was sensitive and specific in detecting a target microbe in 34.3% of specimens, including 1 detection of HSV-1, three detections of HSV-2, and 18 detections of T. pallidum. No H. ducreyi has been detected in Australia since 1998, and none was detected here. No Calymmatobacterium (Klebsiella) granulomatis was detected in the study, but there were 3 detections during ongoing diagnostic use of GUMP-ELAHA in 2004 and 2005. The presence of C. granulomatis was confirmed by restriction enzyme digestion and nucleotide sequencing of the 16S rRNA gene for phylogenetic analysis. Conclusions. GUMP-ELAHA permitted comprehensive detection of common and rare causes of GUD and incorporated noninvasive sampling techniques. Data obtained by using GUMP-ELAHA will aid specific treatment of GUD and better define the prevalence of each microbe among at-risk populations with a view to the eradication of chancroid and donovanosis in Australia.Ian M. Mackay, Gerry Harnett, Neisha Jeoffreys, Ivan Bastian, Kadaba S Sriprakash, David Siebert, and Theo P. Sloot

Radio Loud and Radio Quiet Active Galactic Nuclei

We generated a sample of 409 AGNs for which both the radio luminosity at 5 GHz and the line luminosity in [OIII] 5007 have been measured. The radio luminosity spans a range of ten orders of magnitude, and the [OIII] line luminosity spans a range of eight orders of magnitude --- both considerably larger than the ranges in previous studies. We show that these two quantities are correlated in a similar way for both radio-loud and radio-quiet AGNs. We demonstrate that the observed correlation can be explained in terms of a model in which jets are accelerated and collimated by a vertical magnetic field.Comment: 45 pages inc. 7 figures, 1 table of 15 pages in ps-format. Accept to AJ September 199

Kinematic groups beyond the Solar neighbourhood with RAVE

We analyse the kinematics of disc stars observed by the RAVE survey in and beyond the Solar neighbourhood.We detect significant overdensities in the velocity distributions using a technique based on the wavelet transform.We find that the main local kinematic groups are large scale features, surviving at least up to ~1 kpc from the Sun in the direction of anti-rotation, and also at ~700 pc below the Galactic plane.We also find that for regions located at different radii than the Sun, the known groups appear shifted in the velocity plane. For example, the Hercules group has a larger azimuthal velocity for regions inside the Solar circle and a lower value outside. We have also discovered a new group at (U, V) = (92,-22) km/s in the Solar neighbourhood and confirmed the significance of other previously found groups. Some of these trends detected for the first time are consistent with dynamical models of the effects of the bar and the spiral arms. More modelling is required to definitively characterise the non-axisymmetric components of our Galaxy using these groups.Comment: Minor changes to match the accepted version in MNRAS Letter