The Role of Constraints in a Segregation Model: The Symmetric Case

In this paper we study the effects of constraints on the dynamics of an adaptive segregation model introduced by Bischi and Merlone (2011). The model is described by a two dimensional piecewise smooth dynamical system in discrete time. It models the dynamics of entry and exit of two populations into a system, whose members have a limited tolerance about the presence of individuals of the other group. The constraints are given by the upper limits for the number of individuals of a population that are allowed to enter the system. They represent possible exogenous controls imposed by an authority in order to regulate the system. Using analytical, geometric and numerical methods, we investigate the border collision bifurcations generated by these constraints assuming that the two groups have similar characteristics and have the same level of tolerance toward the members of the other group. We also discuss the policy implications of the constraints to avoid segregation

Forward and Backward Dynamics in implicitly defined Overlapping Generations Models

In dynamic economic models derived from optimization principles, the forward equilibrium dynamics may not be uniquely defined, while the backward dynamics is well defined. We derive properties of the global forward equilibrium paths based on properties of the backward dynamics. We propose the framework of iterated function systems (IFS) to describe the set of forward equilibria, and apply the IFS framework to a one- and a two-dimensional version of the overlapping generations (OLG)-model. We show that, if the backward dynamics is chaotic and has a homoclinic orbit (a “snap-back repellerâ€) the set of forward equilibrium paths converges to a fractal attractor. Forward equilibria may be interpreted as sunspot equilibria, where a random sunspot sequence determines equilibrium selection at each date.

A statistical procedure for testing financial contagion

The analysis of the relationships among financial markets and the identification of financial contagion episodes are relatively recent in the economic analysis and have experienced a rapid development in the last decade, coinciding with the occurrence of relevant financial crises which had effects that spread outside the geographical areas where they originally started. The increasing interest in this topic has lead to the definition of different tests for detecting the existence of financial contagion (Corsetti et al., 2001; Forbes and Rigobon, 2001; Dungey et al., 2004; Allen and Gale, 2005; Rodriguez, 2007; Krishnamurthy, 2009; Sugihara, 2010). However, conclusions on both theoretical and statistical analyses of financial contagion are far from unique. The changes in the international dynamics of returns, which in the last decades has been characterized by increases in both volatilities and asset price synchronicities in different countries, have raised even further the scientific interest in this topic. In this paper, we propose a new methodology for the evaluation of contagion based on the extent of disequilibria in financial dynamics and, in this framework, we define an innovative test for the detection of contagion which specifically identifies the disequilibrium originated by the international transmission of financial crises and their relationships with the behaviours of market participants. Disequilibria exogenously generated by the spread of the effects of a crisis beyond the dynamic process describing endogenous amplification of volatility from one country to other countries are attributed to contagion phenomena. In this framework, contagion effects are separated from the endogenous transmission processes which have their genesis in both the pricing process system and the investor\u2019s behaviours and which are responsible for the amplification of cross-market financial interdependence. In this paper, we discuss the theoretical framework underlying our approach and define a new econometric model for evaluating contagion among countries

Market mood, adaptive beliefs and asset price dynamics

Empirical evidence has suggested that, facing different trading strategies and complicated decision, the proportions of agents relying on particular strategies may stay at constant level or vary over time. This paper presents a simple "dynamic market fraction" model of two groups of traders, fundamentalists and trend followers, under a market maker scenario. Market mood and evolutionary adaption are characterized by fixed and adaptive switching fraction among two groups, respectively. Using local stability and bifurcation analysis, as well as numerical simulation, the role played by the key parameters in the market behaviour is examined. Particular attention is paid to the impact of the market fraction, determined by the fixed proportions of confident fundamentalists and trend followers, and by the proportion of adaptively rational agents, who adopt different strategies over time depending on realized profits. © 2005 Elsevier Ltd. All rights reserved

The Emergence ofBull and BearDynamics in a Nonlinear Model of Interacting Markets

We develop a three-dimensional nonlinear dynamic model in which the stock markets of two countries are linked through the foreign exchange market. Connections are due to the trading activity of heterogeneous speculators. Using analytical and numerical tools, we seek to explore how the coupling of the markets may affect the emergence ofbull and bearmarket dynamics. The dimension of the model can be reduced by restricting investors' trading activity, which enables the dynamic analysis to be performed stepwise, from low-dimensional cases up to the full three-dimensional model. In our paper we focus mainly on the dynamics of the one- and two- dimensional cases, with numerical experiments and some analytical results, and also show that the main features persist in the three-dimensional model

Mental pain in eating disorders: An exploratory controlled study

Mental pain (MP) is a transdiagnostic feature characterized by depression, suicidal ideation, emotion dysregulation, and associated with worse levels of distress. The study explores the presence and the discriminating role of MP in EDs in detecting patients with higher depressive and ED-related symptoms. Seventy-one ED patients and 90 matched controls completed a Clinical Assessment Scale for MP (CASMP) and the Mental Pain Questionnaire (MPQ). ED patients also completed the Beck Depression Inventory-II (BDI-II), Clinical Interview for Depression (CID-20), and Eating Attitudes Test (EAT-40). ED patients exhibited significantly greater severity and higher number of cases of MP than controls. Moreover, MP resulted the most important cluster predictor followed by BDI-II, CID-20, and EAT-40 in discriminating between patients with different ED and depression severity in a two-step cluster analysis encompassing 87.3% (n = 62) of the total ED sample. Significant positive associations have been found between MP and bulimic symptoms, cognitive and somaticaffective depressive symptoms, suicidal tendencies, and anxiety-related symptoms. In particular, those presenting MP reported significantly higher levels of depressive and anxiety-related symptoms than those without. MP represents a clinical aspect that can help to detect more severe cases of EDs and to better understand the complex interplay between ED and mood symptomatology

Treatment of squamous cell carcinoma of the anal canal (SCCA): A new era?

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Irrational beliefs and their role in specific and non-specific eating disorder symptomatology and cognitive reappraisal in eating disorders

Background: Research on which specific maladaptive cognitions characterize eating disorders (ED) is lacking. This study explores irrational beliefs (IBs) in ED patients and controls and the association between IBs and ED-specific and non-specific ED symptomatology and cognitive reappraisal. Methods: 79 ED outpatients with anorexia nervosa, bulimia nervosa, or other specified feeding or eating disorders and 95 controls completed the Attitudes and Beliefs Scale-2 (ABS-2) for IBs. ED outpatients also completed the Eating Disorder Inventory-3 (EDI-3) for ED-specific (EDI-3-ED Risk) and non-specific (EDI-3-General Psychological Maladjustment) symptomatology; General Health Questionnaire (GHQ) for general psychopathology; Emotion Regulation Questionnaire (ERQ) for cognitive reappraisal. Results: Multivariate analysis of variance with post hoc comparisons showed that ED outpatients exhibit greater ABS-2-Awfulizing, ABS-2-Negative Global Evaluations, and ABS-2-Low Frustration Tolerance than controls. No differences emerged between ED diagnoses. According to stepwise linear regression analyses, body mass index (BMI) and ABS-2-Awfulizing predicted greater EDI-3-ED Risk, while ABS-2-Negative Global Evaluations and GHQ predicted greater EDI-3-General Psychological Maladjustment and lower ERQ-Cognitive Reappraisal. Con-clusion: Awfulizing and negative global evaluation contribute to better explaining ED-specific and non-specific ED symptoms and cognitive reappraisal. Therefore, including them, together with BMI and general psychopathology, when assessing ED patients and planning cognitive–behavioral treatment is warranted