Nonequilibrium Phase Transitions in a Driven Sandpile Model

We construct a driven sandpile slope model and study it by numerical simulations in one dimension. The model is specified by a threshold slope \sigma_c\/, a parameter \alpha\/, governing the local current-slope relation (beyond threshold), and $j_{\rm in}$, the mean input current of sand. A nonequilibrium phase diagram is obtained in the \alpha\, -\, j_{\rm in}\/ plane. We find an infinity of phases, characterized by different mean slopes and separated by continuous or first-order boundaries, some of which we obtain analytically. Extensions to two dimensions are discussed.Comment: 11 pages, RevTeX (preprint format), 4 figures available upon requs

Evolution of early continental crust

The present article reviews the evolution of continental crust since the time the earth began to inscribe a permanent history in rocks of the cratonic nuclei. The existence of a sialic crust prior to 4200 Ma ago, soon after the permobile stage of the earth, is documented by detrital zircon in the Precambrian metaconglomerate of Neyerer Complex, Western Australia. The evolution of Archaean crust (> 2500 Ma) is discussed in terms of currently used Nd model-age calculations, based on a depleted mantle evolutionary model. The model fits the generally accepted assumption that LREE depletion of the upper mantle commenced very early in the earth's history and that the present-day MORB is the best representative for the Nd-isotopic composition of today's depleted mantle. Finally, the mechanisms for growth or accretion of the continental crust and the incompatibility of thickened crust during Archaean time are discussed

Independent Domination in Some Wheel Related Graphs

A set S of vertices in a graph G is called an independent dominating set if S is both independent and dominating. The independent domination number of G is the minimum cardinality of an independent dominating set in G . In this paper, we investigate the exact value of independent domination number for some wheel related graphs

Graphs with equal domination and independent domination number

A set S of vertices of a graph G is an independent dominating set of G if S is an independent set and every vertex not in S is adjacent to a vertex in S. The independent domination number of G, denoted by i(G), is the minimum cardinality of an independent dominating set of G. In this paper, some new classes of graphs with equal domination and independent domination numbers are presented and exact values of their domination and independent domination numbers are determined.Publisher's Versio

Predicting wildlife reservoirs and global vulnerability to zoonotic Flaviviruses.

Flaviviruses continue to cause globally relevant epidemics and have emerged or re-emerged in regions that were previously unaffected. Factors determining emergence of flaviviruses and continuing circulation in sylvatic cycles are incompletely understood. Here we identify potential sylvatic reservoirs of flaviviruses and characterize the macro-ecological traits common to known wildlife hosts to predict the risk of sylvatic flavivirus transmission among wildlife and identify regions that could be vulnerable to outbreaks. We evaluate variability in wildlife hosts for zoonotic flaviviruses and find that flaviviruses group together in distinct clusters with similar hosts. Models incorporating ecological and climatic variables as well as life history traits shared by flaviviruses predict new host species with similar host characteristics. The combination of vector distribution data with models for flavivirus hosts allows for prediction of  global vulnerability to flaviviruses and provides potential targets for disease surveillance in animals and humans

Low dose intravenous infusion technique with ketamine

Low dose ketamine is a relatively new technique. The recommended doses vary considerably. It was therefore decided to establish the minimum dose of ketamine required to produce satisfactory analgesia, sedation and amnesia in 50% of a population of adult volunteers. Twenty adult volunteers aged 20 to 42 years were the subjects of the study. Twenty minutes following intravenous (iv) pre-treatment with 0·3 mg of atropine and 0·2 mg/kg of diazepam each volunteer received a bolus of ketamine 1·0 mg/kg iv followed by ketamine iv infusion at the rate of either0·5 mg/kg/hour(10cases) or 1·0 mg/kg/hour (10 cases). The grade of sedation was determined on a scale of 1–5 and the frequency of amnesia was assessed using visual memory cards. Analgesia was determined by pin prick. Diazepam alone produced no analgesia and only moderate degree of sedation. Ketamine produced satisfactory analgesia to pin prick in both the groups. Ketamine bolus produced marked sedation for about 20 min followed by moderate sedation during iv infusion in both the groups. During the iv infusion of ketamine at arate of 0·5 mg/kg/hour the amnesic effects declined to 20% in 45 minutes, while during infusion of 10 mg/kg/hour the frequency reached a maximum at 50–60%. The minimum dose of ketamine required to produce amnesia in 50% of this population was therefore 1·0 mg/kg/hour after a bolus injection of 1·0 mg/kg given iv.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75725/1/j.1365-2044.1980.tb03882.x.pd

Edge wetting of an Ising three-dimensional system

The effect of edge on wetting and layering transitions of a three-dimensional spin-1/2 Ising model is investigated, in the presence of longitudinal and surface magnetic fields, using mean field (MF) theory and Monte Carlo (MC) simulations. For T=0, the ground state phase diagram shows that there exist only three allowed transitions, namely: surface and bulk transition, surface transition and bulk transition. However, there exist a surface intra-layering temperature $T_{L}^{s}$, above which the surface and the intra-layering surface transitions occur. While the bulk layering and intra-layering transitions appear above an other finite temperature $T_{L}^{b} (\ge T_{L}^{s})$. These surface and bulk intra-layering transitions are not seen in the perfect surfaces case. Numerical values of $T_{L}^{s}$ and $T_{L}^{b}$, computed by Monte Carlo method are found to be smaller than those obtained using mean field theory. However, the results predicted by the two methods become similar, and are exactly those given by the ground state phase diagram, for very low temperatures. On the other hand, the behavior of the local magnetizations as a function of the external magnetic field, shows that the transitions are of the first order type. $T_{L}^{s}$ and $T_{L}^{b}$ decrease when increasing the system size and/or the surface magnetic field. In particular, $T_{L}^{b}$ reaches the wetting temperature $T_{w}$ for sufficiently large system sizes.Comment: 11 Pages latex, 12 Figures P