The Extended Line Region of 3C 299

We present results of HST observations of the radio galaxy 3C 299. The broad-band F702W (R) and F555W (V) images (WFPC2/PC) show an elliptical galaxy, with a comet-like structure extending to the NE in the radio jet direction. The [OIII]$\lambda$5007 emission line map, shows a bi-conical structure centered on the nucleus, that overlaps the structure found in the broad-band filters. The radio core coincides with the center of the bi-conical structure and the radio axes are aligned with the direction of the cones. These data show clear evidence of a strong interaction between the radio jet and the NE morphology of the galaxy. We show evidence that this NE region is an ENLR; the line-ratio diagnostics show that models involving gas shocked by the radio-jet plus ionization from a precursor HII region, produced itself by the ionizing photons of the postshocked gas on the preshocked gas provide a good match to the observations. We investigate the spatial behavior of the ionizing parameter $U$, by determining the [OIII]/[OII] line ratio which is sensitive to the change of the ionization parameter, and trace its behavior over the ENLR along the radio jet direction. We find that [OIII]/[OII] does not follow a simple dilution model, but rather that it is approximately constant over a large range of distance from the nucleus thus requiring a local source of ionization which seems to be compatible with the shock models driven by the radio jet.Comment: 17 pages, 9 Postscript figures, ApJ accepted, uses aaspp.st

Aromatic Features in AGN: Star-Forming Infrared Luminosity Function of AGN Host Galaxies

We describe observations of aromatic features at 7.7 and 11.3 um in AGN of three types including PG, 2MASS and 3CR objects. The feature has been demonstrated to originate predominantly from star formation. Based on the aromatic-derived star forming luminosity, we find that the far-IR emission of AGN can be dominated by either star formation or nuclear emission; the average contribution from star formation is around 25% at 70 and 160 um. The star-forming infrared luminosity functions of the three types of AGN are flatter than that of field galaxies, implying nuclear activity and star formation tend to be enhanced together. The star-forming luminosity function is also a function of the strength of nuclear activity from normal galaxies to the bright quasars, with luminosity functions becoming flatter for more intense nuclear activity. Different types of AGN show different distributions in the level of star formation activity, with 2MASS> PG> 3CR star formation rates.Comment: Accepted for publication in ApJ, 24 pages, 13 figure

Testing the Hypothesis of Modified Dynamics with Low Surface Brightness Galaxies and Other Evidence

The rotation curves of low surface brightness galaxies provide a unique data set with which to test alternative theories of gravitation over a large dynamic range in size, mass, surface density, and acceleration. Many clearly fail, including any in which the mass discrepancy appears at a particular length-scale. One hypothesis, MOND [Milgrom 1983, ApJ, 270, 371], is consistent with the data. Indeed, it accurately predicts the observed behavior. We find no evidence on any scale which clearly contradicts MOND, and a good deal which supports it.Comment: Accepted for publication in the Astrophysical Journal. 35 pages AAStex + 9 figures. This result surprised the bejeepers out of us, to

Haemodynamic changes during a squat test, pulsatile stress and indices of cardiovascular autonomic neuropathy in patients with long-duration type 1 diabetes.

AIM: Cardiovascular autonomic neuropathy (CAN) and pulsatile stress are considered to be independent cardiovascular risk factors. This study compared haemodynamic changes during an active orthostatic test in adult patients with type 1 diabetes (T1DM), using low versus high RR E/I ratios as a marker of CAN. METHODS: A total of 20 T1DM patients with low RR E/I ratios were compared with 20 T1DM patients with normal RR E/I ratios, matched for gender (1/1 ratio), age (mean: 46years) and diabetes duration (22-26years); 40 matched healthy subjects served as controls. All subjects were evaluated by continuous monitoring of arterial blood pressure (Finapres((R))) and heart rate using a standardized posture test (1-min standing, 1-min squatting, 1-min standing), thus allowing calculation of baroreflex gain. RESULTS: Compared with controls, T1DM patients showed lower RR E/I ratios, reduced baroreflex gains, higher pulsatile stress (pulse pressurexheart rate), greater squatting-induced pulse pressure rises, orthostatic hypotension and reduced reflex tachycardia. Compared with T1DM patients with preserved RR E/I ratios, T1DM patients with low RR E/I ratios showed reduced post-standing reflex tachycardia and baroreflex gain, and delayed blood pressure recovery, but no markers of increased pulsatile stress. Interestingly, decreased baroreflex gain was significantly associated with both pulsatile stress and microalbuminuria. CONCLUSION: The use of RR E/I ratios to separate T1DM patients allows the detection of other CAN markers during an orthostatic posture test, but with no significant differences in pulsatile stress or microalbuminuria. In this context, squatting-derived baroreflex gain appears to be more informative.Peer reviewe

An Unusual Radio Galaxy in Abell 428: A Large, Powerful FR I Source in a Disk-Dominated Host

We report the discovery of a powerful (~10^{24} Watts/Hz) FR I radio source in a highly flattened disk-dominated galaxy. Half of the radio flux from this source is concentrated within the host galaxy, with the remainder in a pair of nearly symmetrical lobes with total extent ~200kpc nearly perpendicular to the disk. The traditional wisdom maintains that powerful, extended radio sources are found only in ellipticals or recent merger events. We report B,R,J, and K imaging, optical spectroscopy, a rotation curve, an IRAS detection, and a VLA 20cm image for this galaxy, 0313-192. The optical and NIR images clearly show a disk. We detect apparent spiral arms and a dust-lane from B band imaging. The reddened nucleus is consistent with extinction by a similar dust-lane. The optical spectrum suggests a central AGN and some evidence of a starburst, with both the AGN and central starlight appearing substantially reddened. From analysis of the extended line emission in [OIII] and H-alpha we derive a rotation curve consistent with an early- type, dusty spiral seen edge-on. From the IRAS detection at 60 and 100 microns, we find that the ratio of Far IR to radio flux places this object firmly as a radio galaxy (i.e. the radio emission is not powered by star formation). The radio structure suggests that the radio source in this galaxy is related to the same physical mechanisms present in jet-fed powerful radio sources, and that such powerful, extended sources can (albeit extremely rarely) occur in a disk-dominated host.Comment: 30 pages LaTeX, 1 table, 8 postscript figures. Accepted for publication in the Astrophysical Journa

The Relationship Between Gas, Stars, and Star Formation in Irregular Galaxies: A Test of Simple Models

We explore various instability models for the onset of star formation in irregular galaxies. Critical gas densities are calculated for gravitational instabilities with a thin, pure-gas disk, and with a thick disk composed of gas and a star-like fluid. We also calculated the stability properties of three dimensional systems including dark matter, considered the thermal state of the gas, and used a modified threshold column density written in terms of the local rate of shear instead of the epicyclic frequency. The model predictions were compared to the azimuthally-averaged present day star formation activity traced by the Halpha surface brightness, and to the 1 Gyr-integrated star formation activity represented by the stellar surface brightness. The ratio of the observed gas density to the critical gas density is lower by a factor of 2 in most of the Im galaxies than it is in spiral galaxies. Star formation ends before this ratio drops significantly in the outer regions, and it remains high in the inner regions where the ratio is often low. These results suggest that the critical gas density does not trace star formation with the same detail in irregular galaxies as it appears to trace it in giant spiral galaxies. The only azimuthally-averaged quantity that correlates with the current star formation activity in irregulars is the stellar surface density. Theoretical implications are discussed.Comment: 39 pages, 7 figures, to appear in Astrophysical Journal, Vol. 493, Feb 1, 199

Dark Matter in Low Surface Brightness Galaxies

Low Surface Brightness (LSB) galaxies form a large population of disc galaxies that extend the Hubble sequence towards extreme late-types. They are only slowly evolving, and still in an early evolutionary state. The Tully-Fisher relation and rotation curves of LSB galaxies both show that LSB galaxies are very dark-matter dominated with respect to ``normal'' high surface brightness (HSB) galaxies. Mass models derived from the rotation curves of LSB and HSB galaxies show that LSB galaxies inhabit less dense and more extended halos. Mass density, which changes with surface brightness, is as important in determining the evolution of a galaxy as total mass is.Comment: 8 pages, uses paspconf.sty. To be published in ``Dark and Visible Matter in Galaxies and Cosmological Implications'', Sesto Pusteria, Italy, 2-5 July, 1996,PASP Conference Series, eds M.Persic and P.Salucci. Also available at http://www.astro.rug.nl/~blok/lsb.htm

Modelling the Interstellar Medium of Low Surface Brightness Galaxies: Constraining Internal Extinction, Disk Color Gradients, and Intrinsic Rotation Curve Shapes

We use a combination of three-dimensional Monte Carlo radiative transfer techniques and multi-wavelength (BRHK,H alpha) imaging data to investigate the nature of the interstellar medium (ISM) in the edge-on, low surface brightness (LSB) galaxy UGC7321. Using realistic models that incorporate multiple scattering effects and clumping of the stars and the interstellar material, we explore the distribution and opacity of the interstellar material (gas+dust), and its effects on the observed stellar disk luminosity profiles, color gradients, and rotation curve shape. We find that UGC7321 contains a small but non-negligible dusty component to its ISM, yielding a B-band optical depth tau_e,B~4.0 from disk edge to center. A significant fraction (~50+/-10%) of the interstellar material in the innermost regions of UGC7321 appears to be contained in a clumpy medium, indicating that LSB galaxies can support a modest, multi-phase ISM structure. In spite of the clear presence of dust, we conclude that the large radial optical color gradients observed in UGC7321 and other similar LSB spiral galaxies cannot be accounted for by dust and must result primarily from significant stellar population and/or metallicity gradients. We show that realistic optical depth effects will have little impact on the observed rotation curves of edge-on disk galaxies and cannot explain the linear, slowly rising rotation curves seen in some edge-on LSB spirals. Projection effects create a far larger uncertainty in recovering the true underlying rotation curve shape of galaxies viewed at inclinations i>85 degrees.Comment: accepted to ApJ; 16 pages, 2 tables, and 18 figures; uses emulateapj.st

A cohort evaluation on arterial stiffness and hypertensive disorders in pregnancy

10.1186/1471-2393-12-160BMC Pregnancy and Childbirth12-BPCM

Oyster Reefs as Natural Breakwaters Mitigate Shoreline Loss and Facilitate Fisheries

Shorelines at the interface of marine, estuarine and terrestrial biomes are among the most degraded and threatened habitats in the coastal zone because of their sensitivity to sea level rise, storms and increased human utilization. Previous efforts to protect shorelines have largely involved constructing bulkheads and seawalls which can detrimentally affect nearshore habitats. Recently, efforts have shifted towards “living shoreline” approaches that include biogenic breakwater reefs. Our study experimentally tested the efficacy of breakwater reefs constructed of oyster shell for protecting eroding coastal shorelines and their effect on nearshore fish and shellfish communities. Along two different stretches of eroding shoreline, we created replicated pairs of subtidal breakwater reefs and established unaltered reference areas as controls. At both sites we measured shoreline and bathymetric change and quantified oyster recruitment, fish and mobile macro-invertebrate abundances. Breakwater reef treatments mitigated shoreline retreat by more than 40% at one site, but overall vegetation retreat and erosion rates were high across all treatments and at both sites. Oyster settlement and subsequent survival were observed at both sites, with mean adult densities reaching more than eighty oysters m−2 at one site. We found the corridor between intertidal marsh and oyster reef breakwaters supported higher abundances and different communities of fishes than control plots without oyster reef habitat. Among the fishes and mobile invertebrates that appeared to be strongly enhanced were several economically-important species. Blue crabs (Callinectes sapidus) were the most clearly enhanced (+297%) by the presence of breakwater reefs, while red drum (Sciaenops ocellatus) (+108%), spotted seatrout (Cynoscion nebulosus) (+88%) and flounder (Paralichthys sp.) (+79%) also benefited. Although the vertical relief of the breakwater reefs was reduced over the course of our study and this compromised the shoreline protection capacity, the observed habitat value demonstrates ecological justification for future, more robust shoreline protection projects