TRADING POULTRY LITTER AT THE WATERSHED LEVEL : A GOAL FOCUSING APPLICATION

We explore the transfer of poultry litter among watersheds incorporating both economic characteristics (litter demand and supply) and environmental characteristics (vulnerability to phosphorus runoff, a major pollutant). A combination of techniques was employed: the Lemunyon-Gilbert P-Index model to determine watershed environmental vulnerability, GIS for land use coverages, and a goal focusing model (incorporating Saaty's eigen-value approach for penalty weight estimation) to identify optimal litter shipments among watersheds. Both primary and secondary data were used. The results should be useful to producers and policy makers in the study area and in other areas where poultry production is linked to water quality, and contribute to a more sustainable poultry sector.Livestock Production/Industries,

TRADING POULTRY LITTER AT THE WATERSHED LEVEL: A GOAL FOCUSING APPLICATION

We explore the transfer of poultry litter among watersheds incorporating both economic and environmental characteristics, and using a goal focusing approach. The results should be useful to producers and policy makers in the study area and in other areas where poultry production is linked to water quality, and contribute to a more sustainable poultry sector.Environmental Economics and Policy, Livestock Production/Industries,

Exploring the Nature of Weak Chandra Sources near the Galactic Centre

We present results from the first near-IR imaging of the weak X-ray sources discovered in the Chandra/ACIS-I survey (Wang et al. 2002) towards the Galactic Centre (GC). These ~800 discrete sources, which contribute significantly to the GC X-ray emission, represent an important and previously unknown population within the Galaxy. From our VLT observations we will identify likely IR counterparts to a sample of the hardest sources, which are most likely X-ray binaries. With these data we can place constraints on the nature of the discrete weak X-ray source population of the GC.Comment: In Proc. of ``Interacting Binaries: Accretion, Evolution, and Outcomes'', eds. L. A. Antonelli et al., AIP, Cefalu, Sicily, 200

Public perceptions of drinking water: A postal survey of residents with private water supplies

Background: In Canada, the legal responsibility for the condition of private water supplies, including private wells and cisterns, rests with their owners. However, there are reports that Canadians test these water supplies intermittently and that treatment of such water is uncommon. An estimated 45% of all waterborne outbreaks in Canada involve non-municipal systems. An understanding of the perceptions and needs of Canadians served by private water supplies is essential, as it would enable public health professionals to better target public education and drinking water policy. The purpose of this study was to investigate the public perceptions of private water supplies in the City of Hamilton, Ontario (Canada), with the intent of informing public education and outreach strategies within the population. Methods: A cross-sectional postal survey of 246 residences with private water supplies was conducted in May 2004. Questions pertained to the perceptions of water quality and alternative water sources, water testing behaviours and the self-identified need for further information. Results: Private wells, cisterns or both, were the source of household water for 71%, 16% and 13% of respondents, respectively. Although respondents rated their water quality highly, 80% also had concerns with its safety. The most common concerns pertained to bacterial and chemical contamination of their water supply and its potential negative effect on health. Approximately 56% and 61% of respondents used in-home treatment devices and bottled water within their homes, respectively, mainly due to perceived improvements in the safety and aesthetic qualities compared to regular tap water. Testing of private water supplies was performed infrequently: 8% of respondents tested at a frequency that meets current provincial guidelines. Two-thirds of respondents wanted more information on various topics related to private water supplies. Flyers and newspapers were the two media reported most likely to be used. Conclusion: Although respondents rated their water quality highly, the majority had concerns regarding the water from their private supply, and the use of bottled water and water treatment devices was extensive. The results of this study suggest important lines of inquiry and provide support and input for public education programs, particularly those related to private water testing, in this population

Thickness dependence of the properties of epitaxial MgB2 thin films grown by hybrid physical-chemical vapor deposition

We have studied the effect of deposition rate and layer thickness on the properties of epitaxial MgB2 thin films grown by hybrid physical-chemical vapor deposition on 4H-SiC substrates. The MgB2 film deposition rate depends linearly on the concentration of B2H6 in the inlet gas mixture. We found that the superconducting and normal-state properties of the MgB2 films are determined by the film thickness, not by the deposition rate. When the film thickness was increased, the transition temperature, Tc, increased and the residual resistivity, rho0, decreased. Above about 300 nm, a Tc of 41.8 K, a rho0 of 0.28 mikroOhm.cm, and a residual resistance ratio RRR of over 30 were obtained. These values represent the best MgB2 properties reported thus far.Comment: 10 pages, 4 figure

Nonlinear ac response of anisotropic composites

When a suspension consisting of dielectric particles having nonlinear characteristics is subjected to a sinusoidal (ac) field, the electrical response will in general consist of ac fields at frequencies of the higher-order harmonics. These ac responses will also be anisotropic. In this work, a self-consistent formalism has been employed to compute the induced dipole moment for suspensions in which the suspended particles have nonlinear characteristics, in an attempt to investigate the anisotropy in the ac response. The results showed that the harmonics of the induced dipole moment and the local electric field are both increased as the anisotropy increases for the longitudinal field case, while the harmonics are decreased as the anisotropy increases for the transverse field case. These results are qualitatively understood with the spectral representation. Thus, by measuring the ac responses both parallel and perpendicular to the uniaxial anisotropic axis of the field-induced structures, it is possible to perform a real-time monitoring of the field-induced aggregation process.Comment: 14 pages and 4 eps figure

The pre-shock gas of SN1006 from HST/ACS observations

We derive the pre-shock density and scale length along the line of sight for the collisionless shock from a deep HST image that resolves the H alpha filament in SN1006 and updated model calculations. The very deep ACS high-resolution image of the Balmer line filament in the northwest (NW) quadrant shows that 0.25 < n_0 < le$ 0.4 cm-3 and that the scale along the line of sight is about 2 x 10^{18} cm, while bright features within the filament correspond to ripples with radii of curvature less than 1/10 that size. The derived densities are within the broad range of earlier density estimates, and they agree well with the ionization time scale derived from the Chandra X-ray spectrum of a region just behind the optical filament. This provides a test for widely used models of the X-ray emission from SNR shocks. The scale and amplitude of the ripples are consistent with expectations for a shock propagating though interstellar gas with ~ 20% density fluctuations on parsec scales as expected from studies of interstellar turbulence. One bulge in the filament corresponds to a knot of ejecta overtaking the blast wave, however. The interaction results from the rapid deceleration of the blast wave as it encounters an interstellar cloud.Comment: 16 pages, 6 figures, to appear in Ap

Correlation Induced Insulator to Metal Transitions

We study a spinless two-band model at half-filling in the limit of infinite dimensions. The ground state of this model in the non-interacting limit is a band-insulator. We identify transitions to a metal and to a charge-Mott insulator, using a combination of analytical, Quantum Monte Carlo, and zero temperature recursion methods. The metallic phase is a non-Fermi liquid state with algebraic local correlation functions with universal exponents over a range of parameters.Comment: 12 pages, REVTE

The Fornax Spectroscopic Survey I. Survey Strategy and Preliminary Results on the Redshift Distribution of a Complete Sample of Stars and Galaxies

The Fornax Spectroscopic Survey will use the Two degree Field spectrograph (2dF) of the Anglo-Australian Telescope to obtain spectra for a complete sample of all 14000 objects with 16.5<=Bj<=19.7 in a 12 square degree area centred on the Fornax Cluster. By selecting all objects---both stars and galaxies---independent of morphology, we cover a much larger range of surface brightness and scale size than previous surveys. In this paper we present results from the first 2dF field. Redshift distributions and velocity structures are shown for all observed objects in the direction of Fornax, including Galactic stars, galaxies in and around the Fornax Cluster, and for the background galaxy population. The velocity data for the stars show the contributions from the different Galactic components, plus a small tail to high velocities. We find no galaxies in the foreground to the cluster in our 2dF field. The Fornax Cluster is clearly defined kinematically. The mean velocity from the 26 cluster members having reliable redshifts is 1560+/-80 km/s. They show a velocity dispersion of 380+/-50 km/s. Large-scale structure can be traced behind the cluster to a redshift beyond z=0.3. Background compact galaxies and low surface brightness galaxies are found to follow the general galaxy distribution.Comment: LaTeX format; uses aa.cls (included). Accepted for publication in Astronomy and Astrophysic

An Application of Finite Element Analysis to Wood Drying

Because of the nonhomogeneous and nonlinear properties of wood, exact solutions for heat and mass transfer are difficult to obtain by current methods of analysis. This work presents a numerical solution for the analysis of drying wood using the finite element method. A nonlinear model was established on a two-dimensional finite element grid structure that considers local density variation. Through the finite element method of analysis of unsteady-state heat and moisture transfer in wood, the dynamic profiles of temperature and moisture content were determined at a series of drying times. The resulting numerical solutions match well with experimental results and with published results. The results will help to extend understanding of wood-water and temperature relations. In future studies, these data can be incorporated into drying stress analysis to analyze checking or warping