Low-T3 Syndrome

Background— Clinical and experimental data have suggested a potential negative impact of low-T3 state on the prognosis of cardiac diseases. The aim of the present prospective study was to assess the role of thyroid hormones in the prognosis of patient population with heart disease. Methods and Results— A total of 573 consecutive cardiac patients underwent thyroid function profile evaluation. They were divided in two subgroups: group I, 173 patients with low T3, ie, with free T3 (fT3) <3.1 pmol/L, and group II, 400 patients with normal fT3 (≥3.1 pmol/L). We considered cumulative and cardiac death events. During the 1-year follow-up, there were 25 cumulative deaths in group I and 12 in group II (14.4% versus 3%, P <0.0001); cardiac deaths were 13 in group I and 6 in group II (7.5% versus 1.5%, P =0.0006). According to the Cox model, fT3 was the most important predictor of cumulative death (hazard ratio [HR] 3.582, P <0.0001), followed by dyslipidemia (HR 2.955, P =0.023), age (HR 1.051, P <0.005), and left ventricular ejection fraction (HR 1.037, P =0.006). At the logistic multivariate analysis, fT3 was the highest independent predictor of death (HR 0.395, P =0.003). A prevalence of low fT3 levels was found in patients with NYHA class III-IV illness compared with patients with NYHA class I-II (χ 2 5.65, P =0.019). Conclusions— Low-T3 syndrome is a strong predictor of death in cardiac patients and might be directly implicated in the poor prognosis of cardiac patients

Procedure di record linkage in epidemiologia: uno studio multicentrico italiano, Record-linkage procedures in epidemiology: an italian multicentre study

Abstract Objective: to compare record linkage (RL) procedures adopted in several Italian settings and a standard probabilistic RL procedure for matching data from electronic health care databases. Design: two health care archives are matched: the hospital discharges (HD) archive and the population registry of four Italian areas. Exact deterministic, stepwise deterministic techniques and a standard probabilistic RL procedure are applied to match HD for acute myocardial infarction (AMI) and diabetes mellitus. Sensitivity and specificity for RL procedures are estimated after manual review. Age and gender standardized annual hospitalization rates for AMI and diabetes are computed using different RL procedures and compared

A note on generalized Nash games played on networks

We investigate a generalized Nash equilibrium problem where players are modeled as nodes of a network and the utility function of each player depends on his/her own action as well as on the actions of his/her neighbors in the network. In the case of a quadratic reference model with shared constraints we are able to derive the variational solution of the game as a series expansion which involves the powers of the adjacency matrix, thus extending a previous result. Our analysis is illustrated by means of some numerical examples

Optimal improvement of communication network congestion via nonlinear programming with generalized Nash equilibrium constraints

We consider a popular model of congestion control in communication networks within the theory of generalized Nash equilibrium problems with shared constraints, where each player is a user who has to send his/her flow over a path in the network. The cost function of each player consists of two parts: a pricing and a utility term. Within this framework we assume that the network system manager can invest a given amount of money to improve the network by enhancing the capacity of its links and, because of limited financial resources, has to make a choice as to which of the links to improve. This choice is made with the help of a performance function which is computed for each set of improvements under consideration and has the property that, once the equilibrium has been reached, maximizes the aggregate utility and minimizes the sum of delays at the links. We model this problem as a nonlinear knapsack problem with generalized Nash equilibrium constraints and show some preliminary numerical experiments

On the approximation of monotone variational inequalities in L^p spaces with probability measure

In this paper we propose an approximation procedure for a class of mono- tone variational inequalities in probabilistic Lebesgue spaces. The implementation of the functional approximation in Lp, with p &gt; 2, leads to a finite dimensional varia- tional inequality whose structure is different from the one obtained in the case p = 2, already treated in the literature. The proposed computational scheme is applied to the random traffic equilibrium problem with polynomial cost functions

Congestion control and optimal maintenance of communication networks with stochastic cost functions: a variational formulation

We consider a game-theory model of congestion control in communica- tion networks, where each player is a user who wishes to maximize his/her flow over a path in the network. We allow for stochastic fluctuations of the cost function of each player, which consists of two parts: a pricing and a utility term. The solution concept we look for is the mean value of the (unique) variational Nash equilibrium of the game. Furthermore, we assume that it is possible to invest a certain amount of money to improve the network by enhancing the capacity of its links and, because of limited financial resources, an optimal choice of the links to improve has to be made. We model the investment problem as a nonlinear knapsack problem with gen- eralized Nash equilibrium constraints in probabilistic Lebesgue spaces and solve it numerically for some examples

Optimal road maintenance investment in traffic networks with random demands

The paper deals with a traffic network with random demands in which some of the roads need maintenance jobs. Due to budget constraints, a central authority has to choose which of them are to be maintained in order to decrease as much as possible the average total travel time spent by all the users, assuming that the network flows are distributed according to the Wardrop equilibrium principle. This optimal road maintenance problem is modeled as an integer nonlinear program, where the objective function evaluation is based on the solution of a stochastic variational inequality. We propose a regularization and approximation procedure for its computation and prove its convergence. Finally, the results of preliminary numerical experiments on some test networks are reported

A note on network games with strategic complements and the Katz-Bonacich centrality measure

We investigate a class of network games with strategic complements and bounded strategy sets by using the variational inequality approach. In the case where the Nash equilibrium of the game has some boundary components, we derive a formula which connects the equilibrium to the Katz-Bonacich centrality measure, thus generalizing the classical result for the interior solution case. Furthermore, we prove that any component of the Nash equilibrium is less than or equal to the corresponding component of the social optimal solution and numerically study the price of anarchy for a small size test problem

A two-stage game theoretical model of social interactions and location choice in city areas

In this article we further investigate a previous game theoretical model of social and economic interactions where players are considered according to their position in a social network and also to their geographic location. Our model allows for intermediate geographic areas, between the city center and the periphery. Moreover, an analysis of some simple but paradigmatic networks shows that the game whose solution yields the players’ location can have multiple equilibria