Invariant Manifolds, Global Attractors and Almost Periodic Solutions of Nonautonomous Difference equations

The article is devoted to the study of quasi-linear nonautonomous difference equations: invariant manifolds, compact global attractors, almost periodic and recurrent solutions and chaotic sets. First, we prove that such equations admit an invariant continuous section (an invariant manifold). Then, we obtain the conditions for the existence of a compact global attractor and characterize its structure. Third, we derive a criterion for the existence of almost periodic and recurrent solutions of the quasi-linear nonautonomous difference equations. Finally, we prove that quasi-linear maps with chaotic base admit a chaotic compact invariant set. The obtained results are applied while studying triangular maps: invariant manifolds, compact global attractors, almost periodic and recurrent solutions and chaotic sets

Continuous Dependence of Attractors on Parameters of Non-Autonomous Dynamical Systems and Infinite Iterated Function Systems

The paper is dedicated to the study of the problem of continuous dependence of compact global attractors on parameters of non-autonomous dynamical systems and infinite iterated function systems (IIFS). We prove that if a family of non-autonomous dynamical systems depending on a parameter is uniformly contracting (in the generalized sense), then each system of this family admits a compact global attractor. As an application we give a generalization of well known Theorem of Bransley concerning the continuous dependence of fractals on parameters

Compact Global Attractors of Discrete Inclusions

The paper is dedicated to the study of the problem of the existence of compact global attractors of discrete inclusions and to the description of its structure. We consider a family of continuous mappings of a metric space W into itself; on the metric space W we consider a discrete inclusion. We give sufficient conditions for the existence of a compact global attractor. If the family consists of a finite number of maps, then the corresponding compact global attractor is chaotic. We study this problem in the framework of non-autonomous dynamical systems (cocyles)

Endogenous Instability in Credit-Constrained Emerging Economies with Leontief Technology

This work provides a framework to analyze the role of financial development as a source of endogenous instability in emerging economies subject to moral hazard problems. We propose and study a dynamic model describing a small open economy with a tradeable good produced by internationally mobile capital and a country specific input, using Leontief technology. We demonstrate that emerging markets could be endogenously unstable since large capital inflows increase risk and exacerbate asymmetric information problems, according to empirical evidences. Using bifurcation and stability analysis, we describe the properties of the system attractors, we assess the plausibility for complex dynamics and, we find out that border collision bifurcations can emerge due to the fact that the state space is piecewise smooth. As a consequence, when a fixed or periodic point loses its stability, the final dynamics may become suddenly chaotic. This fact may explain how financial crises occurred in emerging economies

Non-linear Dynamics in a Business-Cycle Model with Logistic Population Growth

We consider a discrete-time growth model of the Solow type where workers and shareholders have different but constant saving rates and the population growth dynamics is described by the logistic equation able to exhibit complicated dynamics. We show conditions for the resulting system having a compact global attractor and we describe its structure. We also perform a mainly numerical analysis using the critical lines method able to describe the strange attractor and the absorbing area, in order to show how cyclical or complex fluctuations may be produced in a business-cycle model. We study the dynamic behaviour of the model under different ranges of the main parameters, i.e. the elasticity of substitution between the two production factors and the one in the logistic equation (namely m). We prove the existence of complex dynamics when the elasticity of substitution between production factors drops below one (so that capital income declines) or m increases (so that the amplitude of movements in the population growth rate increases)

On the Effect of Labour Productivity on Growth: Endogenous Fluctuations and Complex Dynamics

This paper introduces a sigmoidal production function that considers production possible even when the only input is labour. The long-run behaviour of an economy described by the neoclassical Solow-type growth model with differential savings is investigated considering the technology presented. It is found that labour productivity influences the existence of boom and bust periods as well as the level of capital per capita in equilibrium

Health system response during the european refugee crisis : policy and practice analysis in four Italian regions

The decentralization of the provision of health services at the subnational level produces variations in healthcare offered to asylum seekers (ASs) across the different Italian regions, even if they are entitled to healthcare through the national health service. The present study aims to map the healthcare path and regional policies for ASs upon arrival and identify challenges and best practices. This is a multicentric, qualitative study of migrant health policies and practices at the regional level within four Italian regions. For the analysis, a dedicated tool for the systematic comparison of policies and practices was developed. The collection and analysis of data demonstrated the presence of many items of international recommendations, even if many gaps exist and differences between regions remain. The analysis of practices permitted the identification of three models of care and access. Some aspects identified are as follows: fragmentation and barriers to access; a weakness in or lack of a governance system, with the presence of many actors involved; variability in the response between territories. The inclusion of ASs in healthcare services requires intersectoral actions, involving healthcare sectors and other actors within local social structures, in order to add value to local resources and practices, reinforce networks and contribute to social integration

Evaluation of Residual Stresses Induced by Face Milling Using a Method of Micro-indents

The aim of this study is to determine and evaluate residual stresses induced by face milling in different zones, which are associated with asymmetries in orientation of cutting edge. In this study, a micro-indent method is used to determine these stresses, which were induced in samples of AA 7075-T6 aluminum alloy. The residual displacements were measured, with high accuracy, using a universal measuring machine. This study includes a thorough data analysis using Mohr's circles, which enabled to assess the stress states in all in-plane directions. The results obtained in samples subjected to different combinations of process parameters showed the introduction of compressive normal components for all directions of each zone evaluated. From the high sensitivity of the microindent method used, it was possible to detect smaller differences generated between the levels reaching the stress components in the cutting zones evaluated. Furthermore, these differences were similar for all evaluated directions when the highest feed rate was selected. This significant fact, finally, would reveal equivalent differences between asymmetrical zones, regarding the combination of local plastic deformation and heat reaching the milled surface, for all in-plane directions.Fil: Díaz, FV. 1Departamento de Ingeniería Electromecánica-Departamento de Ingeniería Industrial, Facultad Regional Rafaela, Universidad Tecnológica Nacional, Acuña 49, 2300 Rafaela, ArgentinaFil: Mammana, C.A. 1Departamento de Ingeniería Electromecánica-Departamento de Ingeniería Industrial, Facultad Regional Rafaela, Universidad Tecnológica Nacional, Acuña 49, 2300 Rafaela, ArgentinaFil: Guidobono, A.P.M. División Metrología Dimensional, Centro Regional Rosario (INTI), Ocampo y Esmeralda, 2000 Rosario, ArgentinaPeer Reviewe

Productive Grasslands – The Role of Adapted Species to Increase Ecosystems Resilience

Producers are interested in diversifying grazing systems with native warm-season grasses. Climate variations may result in extreme weather events. For instance, recent studies show strong evidence pointing to an increasing frequency of flooding in the central US, due to changes in both seasonal rainfall and temperature across this region. In a constantly changing climate, adapted species play a crucial role in increasing ecosystems resilience and resistance to extreme weather events. Native grasses may be well adapted to the future changes on climatic conditions, with wide ecological amplitude and resistance under different conditions. Use of adapted warm season grasses, associated with appropriate management practices may enhance pasture ecosystem resilience, and ultimately productivity