Generalized scalar field models with the same energy density and linear stability

We study how the properties of a Lagrangian density for a single real scalar field in flat spacetime change with inclusion of an overall factor depending only on the field. The focus of the paper is to obtain analytical results. So, we show that even though it is possible to perform a field redefinition to get an equivalent canonical model, it is not always feasible to write the canonical model in terms of elementary functions. Also, we investigate the behavior of the energy density and the linear stability of the solutions. Finally, we show that one can find a class of models that present the same energy density and the same stability potential.Comment: 6 pages, 4 figure

Managing performance in quality management: A two level study of employee-perceptions and workplace-performance

Purpose: This paper addresses potential effects of the control element in Quality Management. First, behavioural theories on how elements of performance management can affect organisational performance are examined. Secondly, theoretical models on how perceptions of work conditions may impact wellbeing and performance are considered. Direct and indirect pathways from performance management to productivity/quality are inferred. Methodology: Matched employee-workplace data from an economy-wide survey in Britain and two-level structural equation models are used to test the hypothesised associations. Findings: The use of practices in workplaces is inconsistent with a unified performance management approach. Distinct outcomes are expected from separate components in performance management and some may be contingent on workplace size. For example, within Quality-planning, strategy dissemination is positively associated with workplace-productivity; targets are negatively associated with perceptions of job demands and positively correlated with job satisfaction, which in turn can increase workplace-productivity. With respect to Information & Analysis: keeping and analysing records, or monitoring employee-performance via appraisals that assess training needs, are positively associated with workplace-productivity and quality. Originality: This paper illustrates how control in Quality Management can be effective. Although the merits of performance management are subject to ongoing debate, arguments in the literature have tended to focus on performance appraisal. Analyses of economy-wide data linking performance management practices, within Quality Management, to employee perceptions of work conditions, wellbeing and aggregate performance are rare

From Kinks to Compactons

This work deals with the presence of localized structures in relativistic systems described by a single real scalar field in two-dimensional spacetime. We concentrate on kinks and compactons in models with standard kinematics, and we develop a procedure that help us to smoothly go from kinks to compactons in the suggested scenario. We also show how the procedure works in the braneworld scenario, for flat brane in the five-dimensional spacetime with a single extra dimension of infinite extent. The brane unveils a hybrid profile when the kink becomes a compacton, behaving as a thick or thin brane, depending on the extra dimension being inside or outside a compact space.Comment: 7 pages, 7 figures; new version, to appear in PL

Analytic vortex solutions in generalized models of the Maxwell-Higgs type

This work deals with the presence of analytical vortex configurations in generalized models of the Maxwell-Higgs type in the three-dimensional spacetime. We implement a procedure that allows to decouple the first order equations, which we use to solve the model analytically. The approach is exemplified with three distinct models that show the robustness of the construction. In the third model, one finds analytical solutions that exhibit interesting compact vortex behavior.Comment: 9 pages, 10 figures. To appear in PL

Compact Structures in Standard Field Theory

We investigate the presence of static solutions in models described by real scalar field in two-dimensional spacetime. After taking advantage of a procedure introduced sometime ago, we solve intricate nonlinear ordinary differential equations and illustrate how to find compact structures in models engendering standard kinematics. In particular, we study linear stability and show that all the static solutions we have found are linearly stable.Comment: 6 pages, 11 figures; version published in EP

Vortices in a generalized Maxwell-Higgs model with visible and hidden sectors

We investigate the presence of vortices in generalized Maxwell-Higgs models with a hidden sector. The model engenders $U(1)\times U(1)$ symmetry, in a manner that the sectors are coupled via the visible magnetic permeability depending only on the hidden scalar field. We develop a first order framework in which the hidden sector decouples from the visible one. We illustrate the results with two specific examples, that give rise to the presence of vortices with internal structure.Comment: 9 two-column pages, 4 figures; version to appear in AHE

Experimental Realization of the Fuse Model of Crack Formation

In this work, we present an experimental investigation of the fuse model. Our main goal was to study the influence of the disorder on the fracture process. The experimental apparatus used consisted of an $L\times L$ square lattice with fuses placed on each bond of the lattice. Two types of materials were used as fuses: copper and steel wool wires. The lattice composed only by copper wires varied from a weakly disordered system to a strongly disordered one. The lattice formed only by steel wool wires corresponded to a strongly disordered one. The experimental procedure consisted of applying a potential difference V to the lattice and measuring the respective current I. The characteristic function $I(V)$ obtained was investigated in order to find the scaling law dependence of the voltage and the current on the system size $L$ when the disorder was changed. Our results show that the scaling laws are only verified for the disordered regime.Comment: 4 pages, 8 figures.ep

Job Satisfaction and Quality Management: An Empirical Analysis

Purpose – Quality management requires increasing employee involvement that could empower employees, leading to employee and customer satisfaction. Although the literature describes a picture of increasing job demands and work intensification, the evidence of an association between employee job satisfaction and quality management remains mixed and narrow. The purpose of this paper is to investigate this link in the wider economy, and address the roles of human resource management practices that target direct employee participation (job enrichment and high involvement management) in this relationship. Design/methodology/approach – The Workplace Employment Relations Survey of 2004 (WERS2004) provides information on British workplaces including the use of specific quality and human resource management practices, employees' job satisfaction and other outcomes. Latent variable analysis identifies employers' approaches to quality management, job enrichment and high involvement management. Workplace‐level regression analyses illustrate the link between job satisfaction and various desired organizational outcomes. Hierarchical two‐level regression models are used to assess the link between quality management at workplaces and employee job satisfaction. Findings – Although job satisfaction is positively associated with desired workplace outcomes (organizational commitment, productivity and quality), no significant link between quality management and employee job satisfaction is found. By contrast, a positive association between job enrichment and job satisfaction is confirmed, which may be weakened in the presence of quality management. Practical implications – Given the potential impact of job satisfaction on organizational outcomes, job enrichment features should not be neglected when designing jobs so that an effective quality management strategy can be in place. Some weak positive association between high involvement and quality managements with perceived job demands is also observed, and this should be further investigated in more detailed studies of employee well‐being. Originality/value – This is a large empirical study on an economy‐wide sample of workplaces and their employees