Deep WFPC2 and Ground-based Imaging of a Complete Sample of 3C Quasars and Galaxies

We present the results of an HST and ground-based imaging study of a complete 3C sample of z ~ 1 sources, including 5 quasars and 5 radio galaxies. We have resolved continuum structure around all of our quasars in the WFPC2 images and in four of the five ground-based K' images. All of the quasars have some optical continuum structure that is aligned with the radio axis. In 3 of these cases, some of this optical structure is most likely due to optical synchrotron radiation, including optical counterparts to two radio jets and one radio lobe. Two quasars have aligned continuum and emission-line structures that are probably not due to beamed optical synchrotron emission. In another quasar, we see a red aligned object that lies 3 arcsec beyond the radio lobe, and may be an unassociated foreground galaxy, but has a remarkable morphological resemblance to the radio lobe itself. The radio galaxies and the quasars in this small sample have similar incidence of alignment, and the optical and K' flux densities are consistent within the high dispersion. The average quasar host galaxy luminosity is equivalent to, or a little fainter than, L*. All components around the quasars have optical-infrared colors that are redder than or similar to the colors of their respective nuclei; this is generally more consistent with a stellar rather than scattered origin for the emission. This study provides qualitative support for the unification of FRII quasars and galaxies.Comment: 69 pages, LaTeX (aaspp4.sty); 10 tables (aj_pt4.sty); 22 figures; accepted to A.J., August 199

Deep Spectroscopy in the Field of 3C 212

We present the results of longslit and multiaperture spectroscopy of faint galaxies in the field of the z=1.049 quasar 3C212. We show that an apparently aligned optical feature beyond the NW radio lobe has a redshift z=0.928, and a similarly aligned feature just beyond the SE radio lobe has a redshift z=1.053, quite close to that of the quasar. While the NW optical component is extremely well aligned with the radio jet and has a morphology that is very similar to that of the radio lobe lying 3" interior to it, the fact that we find three other field galaxies with closely similar redshifts indicates that it is most likely a member of an intervening group rather than an unusual example of true alignment with the radio structure. In addition, we have found two galaxies (besides the one near the SE radio lobe) having redshifts close to that of 3C212. We have firm or probable redshifts for 66 out of 82 galaxies we have observed in this field. Comparison with the redshift distribution of faint field galaxies indicates that a large fraction of the remaining 16 galaxies are likely to be at redshifts >1.4. There are at least two low-redshift dwarf starburst galaxies showing low metal abundance and high ionization in our sample; such galaxies are likely to be relatively common in very faint samples, and, under certain conditions, they could be confused with high-redshift objects.Comment: 15 pages, 4 figures, one of which is a separate JPEG plate. To be published in the April 1998 issue of The Astronomical Journa

High-Resolution K' Imaging of the z = 1.786 Radio Galaxy 3C 294

We have obtained imaging in the K' band (~I-band rest frame) of the z=1.786 radio galaxy 3C 294 with the 36-element curvature-sensing adaptive optics system Hokupa`a and the Canada-France-Hawaii Telescope. At a resolution of < \~0."15, the galaxy is seen as a group of small but resolved knots distributed over a roughly triangular region ~1."4 across. The interpretation of the structure depends on the location of the nucleus, as indicated by the compact radio core. Its position is uncertain by > ~0."5 (2-sigma) because of uncertainties in the optical astrometry, but our best estimate places it at or near the southern apex of the distribution. If this location is correct, the most likely interpretation is that of a hidden quasar nucleus illuminating dusty infalling dwarf-galaxy-like clumps having characteristic sizes of ~1.5 kpc.Comment: 8 pages. One figure in gif format. Postscript version including fig. (240 kb) available at http://www.ifa.hawaii.edu/~canaguby/preprints.html To appear in ApJ. Letter

Morphological and genetic differentiation of Patella granularis (Gastropoda: Patellidae): recognition of two sibling species along the coast of southern Africa

Morphological and isozyme variations between 13 populations of the species hitherto named Patella granularis were investigated to see whether differences in shell structure between the west coast versus the south and east coasts of southern Africa are supported by other morphological features or by genetic differences. The shells showed a definite decrease in size from west to east, but this is correlated with productivity and is of no diagnostic use in distinguishing between populations. Discriminant functions analysis based on shell morphometrics failed to separate populations from the three coastal regions. Shells from the northern east coast do, however, have shell nodules with a dark pigmentation, distinctly separating them from those further south and west. No differences in radular or soft part morphology were detected between the populations, but the four northernmost populations on the east coast have a significantly shorter Z looping of the gut than the other populations along the coast. Significant microstructural differences in the sperm were also detected between these two groups of populations. Electrophoretic analysis of 16 enzyme loci failed to detect any significant differences between the west and south coast populations, but revealed a genetic identity (Nei) of 0.528 as well as four diagnostic alleles between the four northernmost populations from the east coast compared with those to the south and west. The two genetically distinct forms occurred sympatrically at one of the study sites on the east coast (Coffee Bay). It was concluded the two groupings were sufficiently different to warrant the recognition of a separate species, which is centred in KwaZulu-Natal on the east coast and extends south to Coffee Bay, from where it is replaced by P. granularis. There is, however, no evidence at all that the west coast populations are in any way separable from the remaining populations of P. granularis on the south coast

Two Active Nuclei in 3C294

The z=1.786 radio galaxy 3C294 lies <10 arsec from a 12th mag star and has been the target of at least three previous investigations using adaptive-optics imaging. A major problem in interpreting these results is the uncertainty in the precise alignment of the radio structure with the H or K-band AO imaging. Here we report observations of the position of the AO guide star with the HST Fine Guidance Sensor, which, together with positions from the U. S. Naval Observatory's UCAC2 catalog, allow us to register the infrared and radio frames to an accuracy of better than 0.1 arcsec. The result is that the nuclear compact radio source is not coincident with the brightest discrete object in the AO image, an essentially unresolved source on the eastern side of the light distribution, as Quirrenbach et al. (2001) had suggested. Instead, the radio source is centered about 0.9 arcsec to the west of this object, on one of the two apparently real peaks in a region of diffuse emission. Nevertheless, the conclusion of Quirrenbach et al. that 3C294 involves an ongoing merger appears to be correct: analysis of a recent deep Chandra image of 3C294 obtained from the archive shows that the nucleus comprises two X-ray sources, which are coincident with the radio nucleus and the eastern stellar object. The X-ray/optical flux ratio of the latter makes it extremely unlikely that it is a foreground Galactic star.Comment: 16 pages, including 4 figures. To appear in ApJ, vol. 60

Targeting the live market: recovery of Norway lobsters Nephrops norvegicus (L.) from trawl-capture as assessed by stress-related parameters and nucleotide breakdown

The recovery potential of Norway lobsters (Nephrops norvegicus) held in on-board seawater tanks after trawl-capture was assessed at two different times of the year (winter and summer). Survival recorded 24 h after trawl-capture was 84.83 ± 0.93% in the winter compared to 75.35 ± 2.92% in the summer. Stress-related parameters in the muscle (arginine phosphate, glycogen and L-lactate) and in the haemolymph (L-lactate) were measured, together with nucleotide breakdown products in the muscle (yielding the “Adenylate Energy Charge” or AEC ratio). All parameters analysed were responsive to the stress of the trawl-capture and subsequently recovered towards resting values, but did so at different rates. The fact that some measures recovered at a faster rate than others should be taken into account when trying to develop an index of metabolic stress for this species. Animals trawled in the winter recovered to AEC values above 0.8 within 4 h of placing them in on-board seawater tanks, whereas animals trawled in the summer took 24 h to reach these values. Furthermore, at the end of the trials animals trawled in the summer presented significantly higher haemolymph L-lactate and lower muscle glycogen reserves than the animals trawled in the winter, suggesting a faster recovery in the winter compared to the summer. Finally, animals in the winter were better able to endure further stresses (an emersion of 1 h while animals were transported to the commercial handling facilities). Therefore, as a code of practice it is advised that trawled N. norvegicus directed to the live trade should be allowed to recover for at least 4–6 h in on-board tanks, and extra care should be taken especially in the summer, if further stresses such as additional emersion are to be applied within the first 24 h after capture

E-cadherin can limit the transforming properties of activating β-catenin mutations

Wnt pathway deregulation is a common characteristic of many cancers. But only Colorectal Cancer predominantly harbours mutations in APC, whereas other cancer types (hepatocellular carcinoma, solid pseudopapillary tumours of pancreas) have activating mutations in β-catenin (CTNNB1). We have compared the dynamics and the potency of β-catenin mutations in vivo. Within the murine small intestine (SI), an activating mutation of β-catenin took much longer to achieve a Wnt deregulation and acquire a crypt-progenitor-cell (CPC) phenotype than Apc or Gsk3 loss. Within the colon, a single activating mutation of β-catenin was unable to drive Wnt deregulation or induce the CPC phenotype. This ability of β-catenin mutation to differentially transform the SI versus the colon correlated with significantly higher expression of the β-catenin binding partner E-cadherin. This increased expression is associated with a higher number of E-cadherin:β-catenin complexes at the membrane. Reduction of E-cadherin synergised with an activating mutation of β-catenin so there was now a rapid CPC phenotype within the colon and SI. Thus there is a threshold of β-catenin that is required to drive transformation and E-cadherin can act as a buffer to prevent β-catenin accumulation