Compelled to do the right thing

We use a model of opinion formation to study the consequences of some mechanisms attempting to enforce the right behaviour in a society. We start from a model where the possible choices are not equivalent (such is the case when the agents decide to comply or not with a law) and where an imitation mechanism allow the agents to change their behaviour based on the influence of a group of partners. In addition, we consider the existence of two social constraints: a) an external authority, called monitor, that imposes the correct behaviour with infinite persuasion and b) an educated group of agents that act upon their fellows but never change their own opinion, i.e., they exhibit infinite adamancy. We determine the minimum number of monitors to induce an effective change in the behaviour of the social group, and the size of the educated group that produces the same effect. Also, we compare the results for the cases of random social interactions and agents placed on a network. We have verified that a small number of monitors are enough to change the behaviour of the society. This also happens with a relatively small educated group in the case of random interactions.Comment: 8 pages, 9 figures, submitted to EPJ

Unsupervised learning for cross-domain medical image synthesis using deformation invariant cycle consistency networks

Recently, the cycle-consistent generative adversarial networks (CycleGAN) has been widely used for synthesis of multi-domain medical images. The domain-specific nonlinear deformations captured by CycleGAN make the synthesized images difficult to be used for some applications, for example, generating pseudo-CT for PET-MR attenuation correction. This paper presents a deformation-invariant CycleGAN (DicycleGAN) method using deformable convolutional layers and new cycle-consistency losses. Its robustness dealing with data that suffer from domain-specific nonlinear deformations has been evaluated through comparison experiments performed on a multi-sequence brain MR dataset and a multi-modality abdominal dataset. Our method has displayed its ability to generate synthesized data that is aligned with the source while maintaining a proper quality of signal compared to CycleGAN-generated data. The proposed model also obtained comparable performance with CycleGAN when data from the source and target domains are alignable through simple affine transformations

A Novel Approach to the Cosmological Constant Problem

We propose a novel infinite-volume brane world scenario where we live on a non-inflating spherical 3-brane, whose radius is somewhat larger than the present Hubble size, embedded in higher dimensional bulk. Once we include higher curvature terms in the bulk, we find completely smooth solutions with the property that the 3-brane world-volume is non-inflating for a continuous range of positive values of the brane tension, that is, without fine-tuning. In particular, our solution, which is a near-BPS background with supersymmetry broken on the brane around TeV, is controlled by a single integration constant.Comment: 20 pages, revte

Special Massive Spin-2 on de Sitter Space

The theory of a massive spin-2 state on the de Sitter space -- with the mass squared equal to one sixth of the curvature -- is special for two reasons: (i) it exhibits an enhanced local symmetry; (ii) it emerges as a part of the model that gives rise to the self-accelerated Universe. The known problems of this theory are: either it cannot be coupled to a non-conformal conserved stress-tensor because of the enhanced symmetry, or it propagates a ghost-like state when the symmetry is constrained by the Lagrange multiplier method. Here we propose a solution to these problems in the linearized approximation.Comment: 9 pages, reference added, JCAP versio

Effect of band filling in the Kondo lattice: A mean-field approach

The usual Kondo-lattice, including an antiferromagnetic exchange interaction between nearest-neighboring localized spins, is treated here in a mean-field scheme that introduces two mean-field parameters: one associated with the local Kondo effect, and the other related to the magnetic correlations between localized spins. Phases with short-range magnetic correlations or coexistence between those and the Kondo effect are obtained. By varying the number of electrons in the conduction band, we notice that the Kondo effect tends to be suppressed away from half filling, while magnetic correlations can survive if the Heisenberg coupling is strong enough. An enhanced linear coefficient of the specific heat is obtained at low temperatures in the metallic state.Comment: 7 pages, ReVTeX two-column, 7 figure

Ralph W. Steen Library 2015 – 2016 Quantitative Comparative Statistical Analysis

For academic libraries at public state universities, the challenge continues on how to evaluate performance, measure progress, and find meaningful ways to demonstrate their worth. The challenge is to find meaningful ways to demonstrate how library programs and services contribute to learning outcomes and student success. This report presents a comparative analysis of Ralph W. Steen Library and ten peer institutions to highlight areas of excellence and under-performance that may warrant further attention

A methodology for cost-effective analysis of hydrokinetic energy projects

The cost-effective analysis (CEA) of hydrokinetic farms is typically based on simplistic assumptions regarding the performance and cost structure of hydrokinetic energy converters (HECs) and, in consequence, may lead to ill-informed decision-making. In this work, a novel approach to selecting the most appropriate combination of HEC and site within a coastal area is developed, with the accurate computation of the CEA parameters as the cornerstone. The approach, which is illustrated through a case study in the Shannon Estuary (W Ireland), encompasses four models, namely: (i) HEC-site selection model, (ii) energy production model, (iii) CAPEX model, and (iv) OPEX model. By avoiding simplistic assumptions, the proposed approach improves on current procedures and enables developers to accurately compute any cost-effective parameter of interest. In particular, operation and maintenance costs are considered, along with economies of scale, which are typically disregarded in existing procedures. Beyond the interest of the results of the Shannon case study, the approach can be implemented in other regions with potential for hydrokinetic energy conversionThis work was supported by the PORTOS project, which is co-financed by the Interreg Atlantic Area Programme, through the European Regional Development Fund [grant number EAPA_784/2018] and ‘Axudas para a consolidación e estruturación de unidades de investigación competitivas nas universidades do Sistema Universitario Galego (2020–22)’ with reference number ED341B 2020/25. During this work, D.M. Fouz was supported by a predoctoral grant of the ‘Convocatoria de contratos predoutorais do Campus de Especialización Campus Terra’ with reference number 8042-272B-64100S

Methods for Evaluating Social Vulnerability to Drought

Social vulnerability to drought is complex and it is reflected by society’s capacity to anticipate, cope with and respond. Here we estimate these aspects of social vulnerability, evaluating the natural resource structure, the economic capacity, the human and civic resources, and aspects of agricultural innovation. These factors are components of a vulnerability index and they can be weighted appropriately in computing the final value of the index. In this chapter we present the results of the index under two valuation scenarios. For Scenario 1 all components are valued equally. For Scenario 2 the human resources component is given 50% of the weight, the economic and natural resource components are given 20% of the weight each, and the agricultural technology is given 10% of the weight. This reflects the assumption that a society with institutional capacity and coordination and mechanisms for public participation is less vulnerable to drought and that agriculture is only one of the sectors affected by drought. The vulnerability index establishes robust conclusions since the range of values across countries does not change with the assumptions under the two scenarios