Simulations of lattice animals and trees

The scaling behaviour of randomly branched polymers in a good solvent is studied in two to nine dimensions, using as microscopic models lattice animals and lattice trees on simple hypercubic lattices. As a stochastic sampling method we use a biased sequential sampling algorithm with re-sampling, similar to the pruned-enriched Rosenbluth method (PERM) used extensively for linear polymers. Essentially we start simulating percolation clusters (either site or bond), re-weigh them according to the animal (tree) ensemble, and prune or branch the further growth according to a heuristic fitness function. In contrast to previous applications of PERM, this fitness function is {\it not} the weight with which the actual configuration would contribute to the partition sum, but is closely related to it. We obtain high statistics of animals with up to several thousand sites in all dimension 2 <= d <= 9. In addition to the partition sum (number of different animals) we estimate gyration radii and numbers of perimeter sites. In all dimensions we verify the Parisi-Sourlas prediction, and we verify all exactly known critical exponents in dimensions 2, 3, 4, and >= 8. In addition, we present the hitherto most precise estimates for growth constants in d >= 3. For clusters with one site attached to an attractive surface, we verify the superuniversality of the cross-over exponent at the adsorption transition predicted by Janssen and Lyssy. Finally, we discuss the collapse of animals and trees, arguing that our present version of the algorithm is also efficient for some of the models studied in this context, but showing that it is {\it not} very efficient for the `classical' model for collapsing animals.Comment: 17 pages RevTeX, 29 figures include

Undermining property rights?: A study of the legality of certain provisions of the Urban Development and Housing Act of 1992 to Property Rights

The Urban Development and Housing Act of 1992 was enacted into law to ensure that urban land reforms will be pursued as well as give a definite procedure for dealing with the underprivileged. This paper will determine the constitutionality of selected provisions of the Urban Development and Housing Act of 1992 or Republic Act 7279. The provisions that are in question are Sections 3(q), 11, and 18. The improvement indicated in Section 11 is unreasonable for people with different status that it violates the equal protection clause. Another provision, the definition of small property owners found in Section 3(q) is questioned because it does not cope to the changes in time. Lastly, Section 18, which is the 20% requirement to contribute to socialize housing, causes undue burden to developers and landowners and its compensation is questionable. The researchers found that certain provisions that are to be questioned are violative of the constitutional provisions on equal protection and deprivation of private property without just compensation. It is suggested that changes must be made to cope for the changes in time and to be upheld as constitutional

An empirical study on the effect of emigration on wages in the Philippines for the year 2003

This paper is an empirical study on the effects of emigration on wages in the Philippines using 2003 labor force survey of National Statistics Office. To determine the effect of emigration on wages in home country, two regression models were used, group and individual. The group model is where workers are group classified by education and age of the total labor force. The other is the individual model where individual data is used. Using the regression models, it is found that emigration directly affect wages. A 10% increase in migrants will increase wages in the Philippines by about 7% using the individual data and by about 4% using the group data

Imaging TB

Please help us populate SUNScholar with the post print version of this article. It can be e-mailed to: [email protected]

Divination, politics, and ancient near eastern empires

Introduction: This volume is the result of a session of the Prophetic Texts in their Ancient Contexts seminar at the 2011 national meeting of the Society of Biblical Literature in San Francisco..