Anisotropic Distribution of SDSS Satellite Galaxies: Planar (not Polar) Alignment

The distribution of satellite galaxies relative to isolated host galaxies in the Sloan Digital Sky Survey (SDSS) is investigated. Host-satellite systems are selected using three different methods, yielding samples of ~3300, ~1600, and \~950 satellites. In the plane of the sky, the distributions of all three samples show highly significant deviations from circular symmetry (> 99.99%, > 99.99%, and 99.79% confidence levels, respectively), and the degree of anisotropy is a strong function of the projected radius, r_p, at which the satellites are found. For r_p < 100 kpc, the SDSS satellites are aligned preferentially with the major axes of the hosts. This is in stark contrast to the Holmberg effect, in which satellites are aligned with the minor axes of host galaxies. The degree of anisotropy in the distribution of the SDSS satellites decreases with r_p and is consistent with an isotropic distribution at of order the 1-sigma level for 250 kpc < r_p < 500 kpc.Comment: ApJ Letters (in press); Discussion section substantially revised, SDSS DR3 included in the analysis, no significant changes to the result

The properties of highly luminous IRAS galaxies

From a complete sample of 154 galaxies identified with IRAS sources in a 304 sq deg area centered on the South Galactic Pole, a subsample of 58 galaxies with L sub IR/L sub B > 3 was chosen. Low resolution spectra were obtained for 30% of the subsample and redshifts and relative emission line intensities were derived. As a class these galaxies are very luminous with = 2.9 x 10 to the 11th power L sub 0 and (L sub IR) max = 1.3 x 10 to the 12th power L sub 0. CCD images and JHK photometry were obtained for many of the subsample. The galaxies are for the most part newly identified and are optically faint, with a majority showing evidence of a recent interaction. Radio continuum observations of all galaxies of the subsample were recently obtained at 20 cm VLA with about 75% being detected in a typical integration time of about 10 minutes

TPSDicyc: Improved deformation invariant cross-domain medical image synthesis

Cycle-consistent generative adversarial network (CycleGAN) has been widely used for cross-domain medical image systhesis tasks particularly due to its ability to deal with unpaired data. However, most CycleGAN-based synthesis methods can not achieve good alignment between the synthesized images and data from the source domain, even with additional image alignment losses. This is because the CycleGAN generator network can encode the relative deformations and noises associated to different domains. This can be detrimental for the downstream applications that rely on the synthesized images, such as generating pseudo-CT for PET-MR attenuation correction. In this paper, we present a deformation invariant model based on the deformation-invariant CycleGAN (DicycleGAN) architecture and the spatial transformation network (STN) using thin-plate-spline (TPS). The proposed method can be trained with unpaired and unaligned data, and generate synthesised images aligned with the source data. Robustness to the presence of relative deformations between data from the source and target domain has been evaluated through experiments on multi-sequence brain MR data and multi-modality abdominal CT and MR data. Experiment results demonstrated that our method can achieve better alignment between the source and target data while maintaining superior image quality of signal compared to several state-of-the-art CycleGAN-based methods

The ESO Slice Project (ESP) galaxy redshift survey: III. The Sample

The ESO Slice Project (ESP) is a galaxy redshift survey extending over about 23 square degrees, in a region near the South Galactic Pole. The survey is ~85% complete to the limiting magnitude b_J=19.4 and consists of 3342 galaxies with redshift determination. The ESP survey is intermediate between shallow, wide angle samples and very deep, one-dimensional pencil beams; the spanned volume is ~ 5 x 10^4 Mpc^3 at the sensitivity peak (z ~ 0.1). In this paper we present the description of the observations and of the data reduction, the ESP redshift catalogue and the analysis of the quality of the velocity determinations.Comment: 10 pages, 4 encapsulated figures, uses A&A LATEX; A&A Supplements in press (June 1998 issue

Internal-quantum-state engineering using magnetic fields

We present a general, semi-classical theory describing the interaction of an atom with an internal state consisting of a number of degenerate energy levels with static and oscillating magnetic fields. This general theory is applied to the 3P2 metastable energy level of neon to determine the dynamics of the populations and coherences that are formed due to the interaction. Through these calculations we demonstrate how the interaction may be used for the internal state preparation of an atom

Anisotropic Locations of Satellite Galaxies: Clues to the Orientations of Galaxies within their Dark Matter Halos

We investigate the locations of the satellites of relatively isolated host galaxies in the Sloan Digital Sky Survey and the Millennium Run simulation. Provided we use two distinct prescriptions to embed luminous galaxies within the simulated dark matter halos (ellipticals share the shapes of their halos, while disks have angular momenta that are aligned with the net angular momenta of their halos), we find a fair agreement between observation and theory. Averaged over scales r_p \le 500 kpc, the satellites of red, high-mass hosts with low star formation rates are found preferentially near the major axes of their hosts. In contrast, the satellites of blue, low-mass hosts with low star formation rates show little to no anisotropy when averaged over the same scale. The difference between the locations of the satellites of red and blue hosts cannot be explained by the effects of interlopers in the data. Instead, it is caused primarily by marked differences in the dependence of the mean satellite location, , on the projected distance at which the satellites are found. We also find that the locations of red, high-mass satellites with low star formation rates show considerably more anisotropy than do the locations of blue, low--mass satellites with high star formation rates. There are two contributors to this result. First, the blue satellites have only recently arrived within their hosts' halos, while the red satellites arrived in the far distant past. Second, the sample of blue satellites is heavily contaminated by interlopers, which suppresses the measured anisotropy compared to the intrinsic anisotropy.Comment: 43 pages, 13 figures, ApJ in pres

The Firefighter Problem: A Structural Analysis

We consider the complexity of the firefighter problem where b>=1 firefighters are available at each time step. This problem is proved NP-complete even on trees of degree at most three and budget one (Finbow et al.,2007) and on trees of bounded degree b+3 for any fixed budget b>=2 (Bazgan et al.,2012). In this paper, we provide further insight into the complexity landscape of the problem by showing that the pathwidth and the maximum degree of the input graph govern its complexity. More precisely, we first prove that the problem is NP-complete even on trees of pathwidth at most three for any fixed budget b>=1. We then show that the problem turns out to be fixed parameter-tractable with respect to the combined parameter "pathwidth" and "maximum degree" of the input graph

Classification of Construction Projects

The final publication is available at World Academy of Science via https://waset.org/Publication/classification-of-construction-projects/10001697 © 2015, This unmodified version is made available under the CC BY-SA 2.0 https://creativecommons.org/licenses/by-sa/2.0/In order to address construction project requirements and specifications, scholars and practitioners need to establish taxonomy according to a scheme that best fits their need. While existing characterization methods are continuously being improved, new ones are devised to cover project properties which have not been previously addressed. One such method, the Project Definition Rating Index (PDRI), has received limited consideration strictly as a classification scheme. Developed by the Construction Industry Institute (CII) in 1996, the PDRI has been refined over the last two decades as a method for evaluating a project's scope definition completeness during front-end planning (FEP). The main contribution of this study is a review of practical project classification methods, and a discussion of how PDRI can be used to classify projects based on their readiness in the FEP phase. The proposed model has been applied to 59 construction projects in Ontario, and the results are discussed