Regional economic integration and foreign direct investment: The case of NAFTA

Abstract and Key Results

Novel velocity and call duration support for QoS provision in mobile wireless networks

This article presents a novel mobility-based resource reservation and call admission control scheme that is applicable to any real wireless multimedia network. The scheme exploits three key mobility parameters - the position, direction, and speed of a mobile unit - together with the duration of a particular call to accurately estimate the cell visiting probability in order to identify a shadow cluster of cells the unit is most likely to visit. Each cell in the cluster reserves resources for an estimated time interval, which is adapted depending on the aggregated probability of all active units visiting a particular cell. Simulation results confirm the superiority of the new scheme over the existing predictive mobility support scheme in terms of three QoS parameters: call blocking rate, call dropping rate, and channel utilization.     

The prognostic factors for early mortality and for total or partial gammagraphic resolution in venous thromboembolic disease

Our objective was to investigate possible factors implicated in either early death from or scintigraphic resolution of pulmonary embolism. To that end we conducted a retrospective study of 116 patients with either a high likelihood of pulmonary thromboembolism (PTE) diagnosed by scintiscan or with a fair probability of PTE by scintiscan accompanied by a positive phlebograph. The images were taken upon admission, at 7 days, 10 days and 6 months. The factors analyzed were age, sex, trauma, immobility, surgery, obesity, hemiplegia, venous insufficiency, cardiopulmonary disease, neoplasia, chest X-ray and ECG alterations, D(A-a)O2 and size of perfusion defects upon admission and 7 to 10 days later. We performed single-variable analyses and multiple logical regression analyses using perfusion defect at 6 months as the dependent variable. The early mortality rate (13%) was higher in patients with neoplasms, a larger alveolar-arterial index and greater perfusion defects upon admission. Scintiscans became normal in 28%. Multivariate analysis to predict total or partial resolution at 6 months showed that size of perfusion defects at 7 to 10 days was the best predictive factor. A cutoff point was calculated by analyzing the ROC for this factor. Thus, when the defect at 7 to 10 days was equal to or greater than 1 segment, the probability of residual defects remaining after 6 months was twice as great (sensitivity 83%, specificity 57%). In conclusion, early death was more likely in PTE patients with neoplasms, larger defects upon admission and greater alveolar-arterial difference. Scintigrams showed resolution 6 months after admission in 28%. The size of perfusion defects 7 to 10 days after admission was the factor that best predicted total of partial resolution at 6 months.