Angular correlations of galaxy distribution

We study the angular correlations of various galaxy catalogs (CfA1, SSRS1, Perseus-Pisces, APM Bright Galaxies and Zwicky). We find that the angular correlation exponent is $\gamma_a= 0.1 \pm 0.1$ rather than $\gamma_a=0.7$ as usually found by the standard correlation function $\omega(\theta)$. We identify the problem in the artificial decay of $\omega(\theta)$. Moreover we find that no characteristic angular scale is present in any of the analyzed catalogs. Finally we show that all the available data are consistent with each other and the angular distribution of galaxies is quite naturally compatible with a fractal structure with $D \approx 2$.Comment: 16 pages, latex, 3 postscript figures. Accepted for publication in Astrophysical Journal Letters. This paper is also available at http://www.phys.uniroma1.it/DOCS/PIL/pil.htm

Circular 78

Historically, sales of exotic meats have been limited only by supply. As supply has increased in recent years, national and international exotic game markets have grown rapidly. In the United States, growth has occurred primarily in the restaurant section, although over-the-counter sales have also increased. The Alaskan reindeer industry is exploring the potential of expanding its meat sales as well as antler sales. Meat production increased from 320,000 pounds in 1987 to 432,000 pounds in 1988. This production increase is reflected in a 27 percent increase in dollar value (Alaska Crop and Livestock Reporting Service, 1989). Under current management procedures, potential meat production has been estimated at 500,000 pounds (Pearson and Lewis, 1988). Any future market expansion is likely to occur in urban Alaska and in areas outside the state (Jones, 1988)

Bivariate galaxy luminosity functions in the Sloan Digital Sky Survey

Bivariate luminosity functions (LFs) are computed for galaxies in the New York Value-Added Galaxy Catalogue, based on the Sloan Digital Sky Survey Data Release 4. The galaxy properties investigated are the morphological type, inverse concentration index, Sérsic index, absolute effective surface brightness (SB), reference frame colours, absolute radius, eClass spectral type, stellar mass and galaxy environment. The morphological sample is flux limited to galaxies with r < 15.9 and consists of 37 047 classifications to an rms accuracy of ± half a class in the sequence E, S0, Sa, Sb, Sc, Sd, Im. These were assigned by an artificial neural network, based on a training set of 645 eyeball classifications. The other samples use r < 17.77 with a median redshift of z∼ 0.08, and a limiting redshift of z < 0.15 to minimize the effects of evolution. Other cuts, for example in axis ratio, are made to minimize biases. A wealth of detail is seen, with clear variations between the LFs according to absolute magnitude and the second parameter. They are consistent with an early-type, bright, concentrated, red population and a late-type, faint, less concentrated, blue, star-forming population. This bimodality suggests two major underlying physical processes, which in agreement with previous authors we hypothesize to be merger and accretion, associated with the properties of bulges and discs, respectively. The bivariate luminosity–SB distribution is fit with the Chołoniewski function (a Schechter function in absolute magnitude and Gaussian in SB). The fit is found to be poor, as might be expected if there are two underlying processes

Examining 'window dressing' : the views of black police associations on recruitment and training

In a previous issue of this journal, Ellis Cashmore (2002 Cashmore, E. 2002. ‘Behind the window dressing: minority ethnic police perspectives on cultural diversity’. Journal of Ethnic and Migration Studies, 28(2): 327–41. [Taylor & Francis Online], [CSA], [Google Scholar] ) discussed two key issues currently confronting police constabularies in England and Wales: the recruitment of minority ethnic officers and civilian staff, and the impact of diversity training now in place for all police officers. Cashmore argued that not only are these policies ineffective in enhancing cultural diversity within constabularies, but that they are harmful, presenting a false outward image of effective action. This article examines Cashmore's arguments and develops them in light of findings from recent research on Black Police Associations (BPAs) in England and Wales. Our findings firstly suggest that, because of heavy involvement with these initiatives and the close relationship BPAs have developed with senior management (in comparison to non-BPA members), they must be considered in any discussion of minority ethnic recruitment and diversity training. In addition, the majority of the officers we interviewed were supportive of current recruitment and training programmes. Secondly, we argue that BPAs are helping to change the nature of the overall police culture to a certain extent. Many minority ethnic officers no longer feel they must downplay their ethnicity as members of constabularies

The local space density of dwarf galaxies

We estimate the luminosity function of field galaxies over a range of ten magnitudes (-22 < M_{B_J} < -12 for H_0 = 100 km/s/Mpc) by counting the number of faint APM galaxies around Stromlo-APM redshift survey galaxies at known distance. The faint end of the luminosity function rises steeply at M_{B_J} \approx -15, implying that the space density of dwarf galaxies is at least two times larger than predicted by a Schechter function with flat faint-end slope. Such a high abundance of dwarf galaxies at low redshift can help explain the observed number counts and redshift distributions of faint galaxies without invoking exotic models for galaxy evolution.Comment: 20 pages, 5 included postscript figures, uses AAS LaTex macros. Accepted for publication in the Astrophysical Journal. Two figures and associated discussion added; results and conclusions unchange

CFD modelling of double-skin facades with venetian blinds

This paper describes CFD modelling of Double Skin Façades (DSF) with venetian blinds inside the façade cavity. The 2-D modelling work investigates the coupled convective, conductive and radiative heat transfer through the DSF system. The angles of the venetian blind can be adjusted and a series of angles (0, 30, 45, 60 and 80 degrees) has been modelled. The modelling results are compared with the measurements from a section of façade tested within a solar simulator and with predictions from a component based nodal model. Agreement between the three methods is generally good. Discrepancies in the results are generally caused by the simplification of the CFD model resulting less turbulence mixing within the façade cavity. The CFD simulation output suggests that the presence of the venetian blinds has led up to 35 percent enhancement in natural ventilation flow for the façade cavity and 75 percent reduction in heat loads for the internal environment. It was also found that little changes of the convective heat transfer coefficients on the glazing surfaces have been caused by the venetian blinds with different angles

Galaxy types in the Sloan Digital Sky Survey using supervised artificial neural networks

Supervised artificial neural networks are used to predict useful properties of galaxies in the Sloan Digital Sky Survey, in this instance morphological classifications, spectral types and redshifts. By giving the trained networks unseen data, it is found that correlations between predicted and actual properties are around 0.9 with rms errors of order ten per cent. Thus, given a representative training set, these properties may be reliably estimated for galaxies in the survey for which there are no spectra and without human intervention