An imaging K-band survey - I: The catalogue, star and galaxy counts

We present results from a large area (552\,\sqamin) imaging $K$-band survey to a 5$\sigma$ limit of $K\simeq 17.3$. We have optical-infrared colours of almost all the objects in the sample. Star-galaxy discrimination is performed and the results used to derive the infrared star and galaxy counts. $K$-band ``no-evolution'' galaxy-count models are constructed and compared with the observed data. In the infrared, there is no counterpart for the large excess of faint galaxies over the no-evolution model seen in optical counts. However, we show that the $K$ counts can be remarkably insensitive to evolution under certain reasonable assumptions. Finally, model predictions for $K$-selected redshift surveys are derived.Comment: MNRAS in press. 21 pages plain TeX; figs plus table 4 available via anonymous ftp from /pub/kgb/paper1/sissa.uu at ftp.ast.cam.ac.u

Deep H-band Galaxy Counts and Half-light Radii from HST/NICMOS Parallel Observations

We present deep galaxy counts and half-light radii from F160W ($\lambda_c=1.6\mu$) images obtained with NICMOS on HST. Nearly 9 arcmin$^2$ have been imaged with camera 3, with $3\sigma$ depths ranging from H = 24.3 to 25.5 in a 0.6$''$ diameter aperture. The slope of the counts fainter than H~$= 20$ is 0.31, and the integrated surface density to H$\leq 24.75$ is $4 \times 10^5$ galaxies per square degree. The half-light radii of the galaxies declines steeply with apparent magnitude. At H~$=24$ we are limited by both the delivered FWHM and the detection threshold of the images.Comment: 8 pages. Accepted for publication in ApJ Letter

Tranformation of Neurospora pyr-4 with defective donor genes

Using the Vollmer/Orbach transformation protocol, transformation frequencies of a pyr-4 (OMP decarboxylase) strain of Neurospora crassa of circa 10(3)/µg are routinely achievable. At these levels of transformation, it is feasible to screen out ectopic integrations and look specifically for homologous integration events. Homologous integrants were sought by transforming a pyr-4 recipient with interrupted or incomplete copies of the cloned pyr-4 gene derived from the pyr+ clone in plasmid pFB6, selecting by complementation of the pyrimidine auxotrophy in the recipien

Why Fast Trains Work: An Assessment of a Fast Regional Rail System in Perth, Australia

Perth’s new 72 km long Southern Rail System opened in 2007. With a maximum speed of 137 km/hr and an average speed of almost 90 km/hr this system acts more like a new high speed rail than a suburban rail system, which in Australia typically averages around 40 km/hr for an all-stops services. The Southern Rail Line was very controversial when being planned as the urban areas served are not at all typical of those normally provided with rail but instead were highly car dependent and scattered low density land uses. Nevertheless it has been remarkably successful, carrying over 70,000 people per day (five times the patronage on the express buses it replaced) and has reached the patronage levels predicted for 2021 a decade ahead of time. The reasons for this success are analyzed and include well-designed interchanges, careful integration of bus services, the use of integrated ticketing and fares without transfer penalties and, crucially the high speed of the system when compared to competing car based trips. The Southern Rail Line in effect explodes the current paradigm of transfer penalties, exposing this as a myth. The lessons for transport planning in low density cities are significant, and are explored further in the paper

Arabidopsis TAO1 is a TIR-NB-LRR protein that contributes to disease resistance induced by the Pseudomonas syringae effector AvrB

The type III effector protein encoded by avirulence gene B (AvrB) is delivered into plant cells by pathogenic strains of Pseudomonas syringae. There, it localizes to the plasma membrane and triggers immunity mediated by the Arabidopsis coiled-coil (CC)-nucleotide binding (NB)-leucine-rich repeat (LRR) disease resistance protein RPM1. The sequence unrelated type III effector avirulence protein encoded by avirulence gene Rpm1 (AvrRpm1) also activates RPM1. AvrB contributes to virulence after delivery from P. syringae in leaves of susceptible soybean plants, and AvrRpm1 does the same in Arabidopsis rpm1 plants. Conditional overexpression of AvrB in rpm1 plants results in leaf chlorosis. In a genetic screen for mutants that lack AvrB-dependent chlorosis in an rpm1 background, we isolated TAO1 (target of AvrB operation), which encodes a Toll-IL-1 receptor (TIR)-NB-LRR disease resistance protein. In rpm1 plants, TAO1 function results in the expression of the pathogenesis-related protein 1 (PR-1) gene, suggestive of a defense response. In RPM1 plants, TAO1 contributes to disease resistance in response to Pto (P. syringae pathovars tomato) DC3000(avrB), but not against Pto DC3000(avrRpm1). The tao1–5 mutant allele, a stop mutation in the LRR domain of TAO1, posttranscriptionally suppresses RPM1 accumulation. These data provide evidence of genetically separable disease resistance responses to AvrB and AvrRpm1 in Arabidopsis. AvrB activates both RPM1, a CC-NB-LRR protein, and TAO1, a TIR-NB-LRR protein. These NB-LRR proteins then act additively to generate a full disease resistance response to P. syringae expressing this type III effector

The Near-Infrared Number Counts and Luminosity Functions of Local Galaxies

This study presents a wide-field near-infrared (K-band) survey in two fields; SA 68 and Lynx 2. The survey covers an area of 0.6 deg.$^2$, complete to K=16.5. A total of 867 galaxies are detected in this survey of which 175 have available redshifts. The near-infrared number counts to K=16.5 mag. are estimated from the complete photometric survey and are found to be in close agreement with other available studies. The sample is corrected for incompleteness in redshift space, using selection function in the form of a Fermi-Dirac distribution. This is then used to estimate the local near-infrared luminosity function of galaxies. A Schechter fit to the infrared data gives: M$^\ast_K = -25.1 \pm 0.3$, $\alpha = -1.3\pm 0.2$ and $\phi^\ast =(1.5\pm 0.5)\times 10^{-3}$ Mpc$^{-3}$ (for H$_0=50$ Km/sec/Mpc and q$_0=0.5$). When reduced to $\alpha=-1$, this agrees with other available estimates of the local IRLF. We find a steeper slope for the faint-end of the infrared luminosity function when compared to previous studies. This is interpreted as due to the presence of a population of faint but evolved (metal rich) galaxies in the local Universe. However, it is not from the same population as the faint blue galaxies found in the optical surveys. The characteristic magnitude ($M^\ast_K$) of the local IRLF indicates that the bright red galaxies ($M_K\sim -27$ mag.) have a space density of $\le 5\times 10^{-5}$ Mpc$^{-3}$ and hence, are not likely to be local objects.Comment: 24 pages, 8 figures, AASTEX 4.0, published in ApJ 492, 45