Potts Models with (17) Invisible States on Thin Graphs

The order of a phase transition is usually determined by the nature of the symmetry breaking at the phase transition point and the dimension of the model under consideration. For instance, q-state Potts models in two dimensions display a second order, continuous transition for q = 2,3,4 and first order for higher q. Tamura et al recently introduced Potts models with "invisible" states which contribute to the entropy but not the internal energy and noted that adding such invisible states could transmute continuous transitions into first order transitions. This was observed both in a Bragg-Williams type mean-field calculation and 2D Monte-Carlo simulations. It was suggested that the invisible state mechanism for transmuting the order of a transition might play a role where transition orders inconsistent with the usual scheme had been observed. In this paper we note that an alternative mean-field approach employing 3-regular random ("thin") graphs also displays this change in the order of the transition as the number of invisible states is varied, although the number of states required to effect the transmutation, 17 invisible states when there are 2 visible states, is much higher than in the Bragg-Williams case. The calculation proceeds by using the equivalence of the Potts model with 2 visible and r invisible states to the Blume-Emery-Griffiths (BEG) model, so a by-product is the solution of the BEG model on thin random graphs.Comment: (2) Minor typos corrected, references update

(Four) Dual Plaquette 3D Ising Models

A characteristic feature of the 3d plaquette Ising model is its planar subsystem symmetry. The quantum version of this model has been shown to be related via a duality to the X-Cube model, which has been paradigmatic in the new and rapidly developing field of fractons. The relation between the 3d plaquette Ising and the X-Cube model is similar to that between the 2d quantum transverse spin Ising model and the Toric Code. Gauging the global symmetry in the case of the 2d Ising model and considering the gauge invariant sector of the high temperature phase leads to the Toric Code, whereas gauging the subsystem symmetry of the 3d quantum transverse spin plaquette Ising model leads to the X-Cube model. A non-standard dual formulation of the 3d plaquette Ising model which utilises three flavours of spins has recently been discussed in the context of dualising the fracton-free sector of the X-Cube model. In this paper we investigate the classical spin version of this non-standard dual Hamiltonian and discuss its properties in relation to the more familiar Ashkin-Teller-like dual and further related dual formulations involving both link and vertex spins and non-Ising spins.Comment: Reviews results in arXiv:1106.0325 and arXiv:1106.4664 in light of more recent simulations and fracton literature. Published in special issue of Entropy dedicated to the memory of Professor Ian Campbel

Application of artificial intelligence techniques for rolling dynamic compaction

Rolling dynamic compaction (RDC), involving non-circular modules towed behind a tractor, is now widespread and accepted among many other soil compaction methods. However, to date, there is no accurate method to reliably predict the increase in soil strength after the application of a given number of passes of RDC. This paper presents the application of artificial intelligence (AI) techniques in the form of artificial neural networks (ANNs) and genetic programming (GP) for a priori prediction of the density improvement by means of RDC in a range of ground conditions. These AI-based models are developed by using in situ soil test data, specifically cone penetration test (CPT) and dynamic cone penetration (DCP) test data obtained from several ground improvement projects that employed the 4- sided, 8-tonne ‘impact roller’. The predictions of ANN- and GP-based models are compared with the corresponding actual values and they show strong correlations (r > 0.8). Additionally, the robustness of the optimal models is investigated in a parametric study and it is observed that the model predictions are in a good agreement with the expected behaviour of RDC.R. A. T. M. Ranasinghe and M. B. Jaks

Interdisciplinary Approach in Finding Integrated Management Solutions to Complex Issues: Case of CKDu in Sri Lanka

The purpose of adopting “Interdisciplinary Approach” is to view the issue in different lenses, to identify the commonalities and integrate those, find gaps if any, in different disciplinary views and fill those gaps with the views found in other disciplines to expand the existing knowledge. This paper reports integrated management solutions found in a study using an interdisciplinary approach on the Chronic Kidney Disease of Unknown Etiology (CKDu). The Chronic Kidney Disease of Unknown Etiology (CKDu) was discovered by the Ministry of Health in the 1990s among the paddy farmers in the North Central Province (NCP) of Sri Lanka. The CKDu is a new form of chronic kidney disease (CKD). The Government Medical Officers Association of Sri Lanka (GMOAS) states that more than 40,000 people are affected countrywide (GMOAS, 2013). Since the problem is complex, interconnected to different domains, and many stakeholders are involved, no single disciplinary approach can provide a comprehensive answer to the problem of CKDu in Sri Lanka. Thus, an interdisciplinary approach has been chosen which looked at the issue from different viewpoints, i.e., environmental, social capitol (support), legal and corporate responsibility. The main objectives of the study were to explore and analyze the effectiveness of the processes and measures so far adopted by the Government of Sri Lanka to handle the issue; to identify the potential of the village level organizations and support groups in developing a solution to the CKDu issue; and to critically analyze the response of agro-chemical companies to the CKDu crisis in Sri Lanka, the legal environment in which they operate, and how to establish their responsibilities and accountability in the search for solutions to the CKDu crisis. Perspectives Taking Theory” is adopted as the conceptual framework throughout the study as a solid theoretical basis for the study. Secondary data were gathered from published literature and primary data were gathered using structured and unstructured interviews, key informant surveys, focal group discussions. All possible stakeholders were interviewed including Government officials, agrochemical companies, lawyers, environmentalists, researchers and affected and non-affected communities. For the community survey Padaviya Division was selected as has a very high prevalence for CKDu. According to the results, degradation of the environment, unplanned agriculture, blind embracing of industrial agriculture, negligence of and caring and restoring the cascade tank systems are major causes of CKDu. Despite efforts by the officials of the Ministry of Health in largely the treatment and to a lesser extent prevention of the disease the cause and effect of the disease had not been looked at in a wholesome manner. The Government has to take a well-coordinated and monitored integrated approach with its multitude of agencies in providing a lasting solution to this issue in the short, medium and long terms. Creating awareness of the disease, early detection, strengthening the implementation of law as to use of agro-chemicals, ensure the supply of clean water are the immediate and short-term remedies but in creating long term remedies it is needed to change the attitudes of the farmers in the over use of agrochemicals or encourage and support them to resort to organic agriculture. As there is no concrete evidence that the agrochemicals are the direct culprit to the disease, it is not practical to sue them for damages. However, through the corporate social responsibility, they can be included in the equation which is more long lasting and sustainable. The existing village level social capital, including religious bodies, civil society organizations, and other resources can be mobilized effectively to address the CKDu problem at village level which is a resource hitherto untapped.Keywords: CKDu, Interdisciplinary, Integrated, Agrochemicals, Corporate social responsibilit