Population extremal optimisation for discrete multi-objective optimisation problems

The power to solve intractable optimisation problems is often found through population based evolutionary methods. These include, but are not limited to, genetic algorithms, particle swarm optimisation, differential evolution and ant colony optimisation. While showing much promise as an effective optimiser, extremal optimisation uses only a single solution in its canonical form – and there are no standard population mechanics. In this paper, two population models for extremal optimisation are proposed and applied to a multi-objective version of the generalised assignment problem. These models use novel intervention/interaction strategies as well as collective memory in order to allow individual population members to work together. Additionally, a general non-dominated local search algorithm is developed and tested. Overall, the results show that improved attainment surfaces can be produced using population based interactions over not using them. The new EO approach is also shown to be highly competitive with an implementation of NSGA-II.No Full Tex

A parallel implementation of ant colony optimization

Ant Colony Optimization is a relatively new class of meta-heuristic search techniques for optimization problems. As it is a population-based technique that examines numerous solution options at each step of the algorithm, there are a variety of parallelization opportunities. In this paper, several parallel decomposition strategies are examined. These techniques are applied to a specific problem, namely the travelling salesman problem, with encouraging speedup and efficiency results.Full Tex

Radiating sources in higher-dimensional gravity

We study a time-dependent 5D metric which contains a static 4D sub-metric whose 3D part is spherically symmetric. An expansion in the metric coefficient allow us to obtain close-to Schwarzschild approximation to a class of spherically-symmetric solutions. Using Campbell's embedding theorem and the induced-matter formalism we obtain two 4D solutions. One describes a source with the stiff equation of state believed to be applicable to dense astrophysical objects, and the other describes a spherical source with a radial heat flow.Comment: Latex, 20 pages, no figures. to appear in J. Math. Phy

Assay for free secretory component and methods for monitoring organ rejection

Methods of monitoring and detecting the early onset of organ injury incident rejection of a organ rejection in an animal are disclosed. The described methods are capable of distinguishing organ rejection injury from other organ tissue damage in the animal. Free secretory component levels in an animal biological fluid (e.g., bile, urine, blood, amniotic fluid) may be used to identify organ rejection in an animal. Multiple and single organ transplant patients may be monitored and diagnosed according to the claimed methods. Biological fluids, such as blood, (serum) or urine, are analyzed immunologically using a particularly adapted ELISA which are then compared to an FSC control concentration to identify elevated FSC values. Animals with test FSC above FSC control concentrations are diagnosed as having an ongoing organ rejection episode. The detection of congenital renal dysfunction in utero is also provided according to the present invention through the measurement of FSC in the amniotic fluid. The described methods are specific for indicating organ rejection tissue injury, and distinguish kidney rejection tissue injury, in particular, from other causes of kidney injury, such as cyclosporin toxicity, urinary tract infection, and urinary obstruction and toxicity (incident to immunosuppressive therapy with cyclosporin). A kit for use in the identification of an organ rejection episode in a patient through measurement of FSC in a biological sample is also provided.Board of Regents, University of Texas Syste

Why supersymmetry should be restored at the TeV scale

It is explained why the curvature associated to the vacuum energy density arising from SUSY breaking cannot be completely transferred to the extra spatial dimensions of a bulk space-time manifold, and it is shown -- without using hierarchy arguments but only the results of current large-scale observations -- why the Tev scale should correspond to the maximal allowed SUSY-breaking scale.Comment: 6 pages. Essay written for the 2008 Awards for Essays on Gravitation (Gravity Research Foundation, USA), and awarded with "Honorable Mention

Mass hierarchy and localization of gravity in extra time

We consider Randall-Sundrum model with localized gravity, replacing the extra compact space-like dimension by a time-like one. In this way the solution to the hierarchy problem can be reconciled with a correct cosmological expansion of the visible universe, just as a trivial result of the sign flip of cosmological constants in the bulk and on the 3-branes relative to the case of extra space-like dimension. Some phenomenological aspects of the proposed scenario related to the tachyonic nature of Kaluza-Klein states of graviton are also discussed.Comment: 10 pages, JHEP format, no figures, typos corrected, to appear in Phys. Lett.

Gravity in the Randall-Sundrum Brane World

We discuss the weak gravitational field created by isolated matter sources in the Randall-Sundrum brane-world. In the case of two branes of opposite tension, linearized Brans-Dicke (BD) gravity is recovered on either wall, with different BD parameters. On the wall with positive tension the BD parameter is larger than 3000 provided that the separation between walls is larger than 4 times the AdS radius. For the wall of negative tension, the BD parameter is always negative but greater than -3/2. In either case, shadow matter from the other wall gravitates upon us. For equal Newtonian mass, light deflection from shadow matter is 25 % weaker than from ordinary matter. Hence, the effective mass of a clustered object containing shadow dark matter would be underestimated if naively measured through its lensing effect. For the case of a single wall of positive tension, Einstein gravity is recovered on the wall to leading order, and if the source is stationary the field stays localized near the wall. We calculate the leading Kaluza-Klein corrections to the linearized gravitational field of a non-relativistic spherical object and find that the metric is different from the Schwarzschild solution at large distances. We believe that our linearized solution corresponds to the field far from the horizon after gravitational collapse of matter on the brane.Comment: 8 pages, 1 figure. Replaced with revised version to be published in Phys. Rev. Lett. Some comments adde

Growth Performance of Holstein Dairy Calves Supplemented with a Probiotic

Administration of antibiotics in both therapeutic and sub-therapeutic doses has been the standard practice for dealing with pathogenic bacteria problems in farm animals since the 1940s. Several types of antibiotics are currently used to promote weight gain and feed efficiency in domestic livestock. There is growing concern that the use of antibiotics as growth promoters may result in the development of resistant populations of pathogenic bacteria and, in turn, influence the therapeutic use of antibiotics. The indiscriminate and improper use of antibiotics in food-producing animals could result in the presence of residues in milk, meat, and other animal food products consumed by humans. One possible alternative to antibiotics is the use of probiotics. Probiotics can be defined as “live microbial feed supplements which beneficially affect the host animal by improving its intestinal microbial balance” (Fuller, 1989). Probiotics introduce beneficial microorganisms into the gut which act to maintain optimal conditions within the gastrointestinal tract and inhibit the growth of pathogenic or other undesirable bacteria