Steady States of a Nonequilibrium Lattice Gas

We present a Monte Carlo study of a lattice gas driven out of equilibrium by a local hopping bias. Sites can be empty or occupied by one of two types of particles, which are distinguished by their response to the hopping bias. All particles interact via excluded volume and a nearest-neighbor attractive force. The main result is a phase diagram with three phases: a homogeneous phase, and two distinct ordered phases. Continuous boundaries separate the homogeneous phase from the ordered phases, and a first-order line separates the two ordered phases. The three lines merge in a nonequilibrium bicritical point.Comment: 14 pages, 24 figure

Potential use of offshore marine structures in rebuilding an overfished rockfish species, bocaccio (Sebastes paucispinis)

Although bocaccio (Sebastes paucispinis) was an economically important rockfish species along the west coast of North America, overfishing has reduced the stock to about 7.4% of its former unfished population. In 2003, using a manned research submersible, we conducted fish surveys around eight oil and gas platforms off southern California as part of an assessment of the potential value of these structures as fish habitat. From these surveys, we estimated that there was a minimum of 430,000 juvenile bocaccio at these eight structures. We determined this number to be about 20% of the average number of juvenile bocaccio that survive annually for the geographic range of the species. When these juveniles become adults, they will contribute about one percent (0.8%) of the additional amount of fish needed to rebuild the Pacific Coast population. By comparison, juvenile bocaccio recruitment to nearshore natural nursery grounds, as determined through regional scuba surveys, was low in the same year. This research demonstrates that a relatively small amount of artificial nursery habitat may be quite valuable in rebuilding an overfished species

Release of mercury halides from KCl denuders in the presence of ozone

KCl-coated denuders have become a standard method for measurement of gaseous oxidized mercury, but their performance has not been exhaustively evaluated, especially in field conditions. In this study, KCl-coated and uncoated quartz denuders loaded with HgCl<sub>2</sub> and HgBr<sub>2</sub> lost 29–55% of these compounds, apparently as elemental mercury, when exposed to ozone (range of 6–100 ppb tested). This effect was also observed for denuders loaded with gaseous oxidized mercury at a field site in Nevada (3–37% of oxidized mercury lost). In addition, collection efficiency decreased by 12–30% for denuders exposed to 50 ppb ozone during collection of HgCl<sub>2</sub>. While data presented were obtained from laboratory tests and as such do not exactly simulate field sampling conditions, these results indicate that the KCl denuder oxidized mercury collection method may not be as robust as previously thought. This work highlights needs for further testing of this method, clear identification of gaseous oxidized mercury compounds in the atmosphere, and development of field calibration methods for these compounds

Release of mercury halides from KCl denuders in the presence of ozone

KCl-coated denuders have become a standard method for measurement of gaseous oxidized mercury, but their performance has not been exhaustively evaluated, especially in field conditions. In this study, KCl-coated and uncoated quartz denuders loaded with HgCl<sub>2</sub> and HgBr<sub>2</sub> lost 29–55% of these compounds, apparently as elemental mercury, when exposed to ozone (range of 6–100 ppb tested). This effect was also observed for denuders loaded with gaseous oxidized mercury at a field site in Nevada (3–37% of oxidized mercury lost). In addition, collection efficiency decreased by 12–30% for denuders exposed to 50 ppb ozone during collection of HgCl<sub>2</sub>. While data presented were obtained from laboratory tests and as such do not exactly simulate field sampling conditions, these results indicate that the KCl denuder oxidized mercury collection method may not be as robust as previously thought. This work highlights needs for further testing of this method, clear identification of gaseous oxidized mercury compounds in the atmosphere, and development of field calibration methods for these compounds

Compaction and Chemical Grouting for Drain Tunnels in Phoenix

Ground runs during ml.m.ng of the Papago Freeway Drain Tunnels posed significant potential risk to utilities, street pavement, and buildings located above and adjacent to one of the three tunnel alignments. Ground response to the larger ground runs resulted in open chimneys and settlement of the ground surface of up to several feet. Modifications to the tunneling machine included addition of poling plates and breasting boards. Further modification to the tunneling method included use of compaction grouting in conjunction with mining for the entire length of one tunnel alignment, and use of chemical grouting to prestabilize the ground surrounding the tunnel opening in areas of high risk utilities and in areas where subsurface conditions suggested that running ground would be encountered during mining. This paper presents a summary of the ground behavior with and without the compaction and chemical grouting and describes the grouting methods

The Effect of γ-Guanidinobutyric Acid on the Clotting Time of Normal Plasma and on the Euglobulin Lysis Time of Fibrinolytically Active Plasma

It has been established that ε-aminocaproic acid (EACA) inhibits the activation of human plasminogen (Ablondi et al., 1959; Alkjaersig, Fletcher, and Sherry, 1959). Because of this observation, this compound has been used extensively to inhibit the pathologically occurring fibrinolytic system in patients. Recently Roberts (1965) reported that another compound, γ-guanidinobutyric acid (GGBA), like EACA, inhibits the lysis of human blood clots. Furthermore, GGBA, unlike EACA, retards the formation of these clots. The present investigation was undertaken to determine whether GGBA inhibits clot formation in the one-stage prothrombin and in the partial thromboplastin time tests. In addition, the ability of GGBA to inhibit clot lysis was tested using blood from a patient showing active fibrinolysis

Inducers of Friend leukaemic cell differentiation in vitro--effects of in vivo administration.

Studies were conducted of the in vivo therapeutic potential of compounds which induce the differentiation of Friend leukaemia cells (FLC) in vitro. DBA2/J mice were inoculated with Friend leukaemia cells grown in tissue culture and at various times thereafter were treated with either N-methylacetamide, dimethylacetamide, or tetramethylurea. While survival was only occasionally prolonged, in every study these agents significantly inhibited leukaemia cell proliferation in the spleen and to a lesser extent in the marrow. These agents had no effect on the rate of proliferation of FLC growing subcutaneously nor on the proliferation of myeloid leukaemia in RFMS mice. These studies indicate that the administration of inducing agents to mice bearing Friend leukaemia can alter the proliferation characteristics of the leukaemia cells and hence suggest that these agents may have therapeutic potential

Environments of interacting transients: impostors and Type IIn supernovae

This paper presents one of the first environmental analyses of the locations of the class of ‘interacting transients’, namely Type IIn supernovae (SNe) and SN impostors. We discuss the association of these transients with star formation, host galaxy type, metallicity and the locations of each event within the respective host. Given the frequent assumption of very high mass progenitors for these explosions from various studies, most notably a direct progenitor detection, it is interesting to note the weak association of these subtypes with star formation as traced by Hα emission, particularly in comparison with Type Ic SNe, which trace the Hα emission and are thought to arise from high-mass progenitors. The radial distributions of these transients compared to Type Ic SNe are also very different. This provides evidence for the growing hypothesis that these ‘interacting transients’ are in fact comprised of a variety of progenitor systems. The events contained within this sample are discussed in detail, where information in the literature exists, and compared to the environmental data provided. Impostors are found to split into two main classes, in terms of environment: SN 2008S-like impostors fall on regions of zero Hα emission, whereas η Carina-like impostors all fall on regions with positive Hα emission. We also find indications that the impostor class originate from lower metallicity environments than Type IIn, Ic and IIP SNe. Key words: supernovae: general – supernovae: individual: 1954J, 1961V, 1987B, 1987F, 1993N, 1994W, 1994ak, 1995N, 1996bu, 1996cr, 1997bs, 1997eg, 1999bw, 1999el, 1999gb, 2000P, 2000cl, 2001ac, 2001fa, 2002A, 2002bu, 2002fj, 2002kg, 2003G, 2003dv, 2003gm, 2003lo, 2005db, 2005gl, 2005ip, 2006am, 2006bv, 2006fp, 2008J, 2008S, 2010dn, 2010jl, NGC2366-V1 – galaxies: general

On the environments of Type Ia supernovae within host galaxies

We present constraints on supernovae type Ia (SNe Ia) progenitors through an analysis of the environments found at the explosion sites of 102 events within star-forming host galaxies. Hα and GALEX near-UV images are used to trace on-going and recent star formation (SF), while broad band B,R, J,K imaging is also analysed. Using pixel statistics we find that SNe Ia show the lowest degree of association with Hα emission of all supernova types. It is also found that they do not trace near-UV emission. As the latter traces SF on timescales less than 100Myr, this rules out any extreme ‘prompt’ delay-times as the dominant progenitor channel of SNe Ia. SNe Ia best trace the B-band light distribution of their host galaxies. This implies that the population within star-forming galaxies is dominated by relatively young progenitors. Splitting SNe by their (B-V) colours at maximumlight, ‘redder’ events show a higher degree of association to H II regions and are found more centrally within hosts. We discuss possible explanations of this result in terms of line of sight extinction and progenitor effects. No evidence for correlations between SN stretch and environment properties is observed. Key words: supernovae: general, galaxies: statistic

Galactic contamination in the QMAP experiment

We quantify the level of foreground contamination in the QMAP Cosmic Microwave Background (CMB) data with two objectives: (a) measuring the level to which the QMAP power spectrum measurements need to be corrected for foregrounds and (b) using this data set to further refine current foreground models. We cross-correlate the QMAP data with a variety of foreground templates. The 30 GHz Ka-band data is found to be significantly correlated with the Haslam 408 MHz and Reich and Reich 1420 MHz synchrotron maps, but not with the Diffuse Infrared Background Experiment (DIRBE) 240, 140 and 100 micron maps or the Wisconsin H-Alpha Mapper (WHAM) survey. The 40 GHz Q-band has no significant template correlations. We discuss the constraints that this places on synchrotron, free-free and dust emission. We also reanalyze the foreground-cleaned Ka-band data and find that the two band power measurements are lowered by 2.3% and 1.3%, respectively.Comment: 4 ApJL pages, including 4 figs. Color figures and data at http://www.hep.upenn.edu/~angelica/foreground.html#qmap or from [email protected]