Long term ordering kinetics of the two dimensional q-state Potts model

We studied the non-equilibrium dynamics of the q-state Potts model in the square lattice, after a quench to sub-critical temperatures. By means of a continuous time Monte Carlo algorithm (non-conserved order parameter dynamics) we analyzed the long term behavior of the energy and relaxation time for a wide range of quench temperatures and system sizes. For q>4 we found the existence of different dynamical regimes, according to quench temperature range. At low (but finite) temperatures and very long times the Lifshitz-Allen-Cahn domain growth behavior is interrupted with finite probability when the system stuck in highly symmetric non-equilibrium metastable states, which induce activation in the domain growth, in agreement with early predictions of Lifshitz [JETP 42, 1354 (1962)]. Moreover, if the temperature is very low, the system always gets stuck at short times in a highly disordered metastable states with finite life time, which have been recently identified as glassy states. The finite size scaling properties of the different relaxation times involved, as well as their temperature dependency are analyzed in detail.Comment: 10 pages, 17 figure

Economic analysis of fertilizer options for maize production in Tanzania

United States Agency for International Developmen

Constructing patch-based ligand-binding pocket database for predicting function of proteins

Background Many of solved tertiary structures of unknown functions do not have global sequence and structural similarities to proteins of known function. Often functional clues of unknown proteins can be obtained by predicting small ligand molecules that bind to the proteins. Methods In our previous work, we have developed an alignment free local surface-based pocket comparison method, named Patch-Surfer, which predicts ligand molecules that are likely to bind to a protein of interest. Given a query pocket in a protein, Patch-Surfer searches a database of known pockets and finds similar ones to the query. Here, we have extended the database of ligand binding pockets for Patch-Surfer to cover diverse types of binding ligands. Results and conclusion We selected 9393 representative pockets with 2707 different ligand types from the Protein Data Bank. We tested Patch-Surfer on the extended pocket database to predict binding ligand of 75 non-homologous proteins that bind one of seven different ligands. Patch-Surfer achieved the average enrichment factor at 0.1 percent of over 20.0. The results did not depend on the sequence similarity of the query protein to proteins in the database, indicating that Patch-Surfer can identify correct pockets even in the absence of known homologous structures in the database

Landscape natural resources management using forage grasses and legume intercrops

United States Agency for International Developmen

Three-dimensional antiferromagnetic q-state Potts models: application of the Wang-Landau algorithm

We apply a newly proposed Monte Carlo method, the Wang-Landau algorithm, to the study of the three-dimensional antiferromagnetic q-state Potts models on a simple cubic lattice. We systematically study the phase transition of the models with q=3, 4, 5 and 6. We obtain the finite-temperature phase transition for q= 3 and 4, whereas the transition temperature is down to zero for q=5. For q=6 there exists no order for all the temperatures. We also study the ground-state properties. The size-dependence of the ground-state entropy is investigated. We find that the ground-state entropy is larger than the contribution from the typical configurations of the broken-sublattice-symmetry state for q=3. The same situations are found for q = 4, 5 and 6.Comment: 9 pages including 9 eps figures, RevTeX, to appear in J. Phys.

Non-existence of stationary two-black-hole configurations

We resume former discussions of the question, whether the spin-spin repulsion and the gravitational attraction of two aligned black holes can balance each other. To answer the question we formulate a boundary value problem for two separate (Killing-) horizons and apply the inverse (scattering) method to solve it. Making use of results of Manko, Ruiz and Sanabria-G\'omez and a novel black hole criterion, we prove the non-existence of the equilibrium situation in question.Comment: 15 pages, 3 figures; Contribution to Juergen Ehlers Memorial Issue (GeRG journal

A fouryear followup of school children after masstreatment for Schistosomiasis and Soil Transmitted Helminths in Mwea, Central Kenya

Poly-parasitism infections are common in school children in tropical regions, especially in Africa. In a school based schistosomiasis and soil-transmitted helminths de-worming model project in Mwea, Kenya, approximately 40,000 school age children from 86 schools were treated annually with a standard dose of praziquantel (40mg/kg body weight) and albendazole (400mg). A cohort of approximately 2,300 children from 5 sentinel schools were followed up at multiple time points each year for four years and examined for intestinal helminths (Schistosoma mansoni, Trichuris trichiura, Hookworm (Necator americanus) and Ascaris lumbricoides). The overall prevalence of infection in the five schools before treatment was 47.4% for S. mansoni, 16.7% for N. americanus, 0.8% for T. trichiura and 1.7% for A. lumbricoides. The mean intensity of infection, as measured by eggs per gram of faeces (epg) was 146.2 for S. mansoni, 36.3 for N. americanus 1.0 for T. trichiura and 35.8 for A. lumbricoides. After 4 rounds of treatment, prevalence of S. mansoni reduced significantly by 88.7% to 5.4% (95%CI=3.6% -7.1%), a 97.1% reduction. The prevalence and intensity of S. mansoni infection varied by school according to its proximity to irrigated area, with those schools closest to the irrigated areas presenting higher infection prevalence and intensity. Re-infection with schistosomiasis following treatment was observed and is likely to reflect continued environmental transmission due to non-treatment of the adult population. Soil-transmitted helminths are less prevalent in the cohort, with corresponding lower intensity. This may allow albendazole treatment to be reduced to every 2 or 3 years. This study has shown that periodic administration of anthelminthic drugs reduces the prevalence and intensity (which is likely to be a close proxy of morbidity) of intestinal parasitic infections in school-age children. Adults in the community could also be targeted where resources allow in order to further increasing the effectiveness of de-worming programmes. Keywords: Soil transmitted helminths, Schistosomiasis, school age, prevalence, Intensity, mass de-worming, school childre