Sub-exponential Solutions of Multidimensional Difference Equations

We shall prove that practically any recursive solutionof a linear multidimensional difference equation increases sub-exponentially.If all the steps of the recursive procedure are of the samedirection, useful growth estimates can be given. The resultsare also generalized to some cases of non-linear difference equationsand sequences in the linear normed space.     

Physics students’ performance using computational modelling activities to improve kinematics graphs interpretation

The purpose of this study was to investigate undergraduate students’ performance while exposed to complementary computational modelling activities to improve physics learning, using the softwares Modellus. Interpretation of kinematics graphs was the physics topic chosen for investigation. The theoretical framework adopted was based on Halloun’s schematic modelling approach and on Ausubel’s meaningful learning theory. The results of this work show that there was a statistically significant improvement in the experimental group students’ performance when compared to the control group, submitted just to a conventional teaching method. Students’ perception with respect to the concepts and mathematical relations, as well as the motivation to learn, originated by the activities, have played a fundamental role in these findings.     

Recovery of Nickel and Cobalt from Spent NiMH Batteries by Electrowinning

For nickel and cobalt recovery from spent NiMH batteries by electrowinning, the effect of different electrowinning parameters as boric acid concentration, temperature, current density, and pH were studied using different synthetic solutions. The optimized operational parameters were applied in an electrowinning test with a solution achieved by leaching the electrodes of NiMH batteries. The electrowinning tests were performed galvanostatically in a two‐compartment cell separated by an anionic membrane. A platinum/iridium‐coated titanium anode and a stainless‐steel cathode were used. A sodium sulfate solution served as anolyte. The results demonstrate the technical viability of nickel and cobalt recovery. The chemical composition of the obtained deposit presented high nickel and cobalt concentrations.     

A critical survey of agent-based wholesale electricity market models

The complexity of electricity markets calls for rich and flexible modeling techniques that help to understand market dynamics and to derive advice for the design of appropriate regulatory frameworks. Agent-Based Computational Economics (ACE) is a fairly young research paradigm that offers methods for realistic electricity market modeling. A growing number of researchers have developed agent-based models for simulating electricity markets. The diversity of approaches makes it difficult to overview the field of ACE electricity research; this literature survey should guide the way through and describe the state-of-the-art of this research area. In a conclusive summary, shortcomings of existing approaches and open issues that should be addressed by ACE electricity researchers are critically discussed.     

Pseudo-Glanzmann thrombasthenia in the course of autoimmune thrombocytopenic purpura

INTRODUCTION: Auto-immune thrombocytopenic purpura is associated with platelet anti-glycoprotein antibodies, particularly with anti-GPIIb/IIIa complex. Persistence of these antibodies sometimes leads to acquired auto-immune thrombopathy. EXEGESIS: We report the case of a woman treated by splenectomy for auto-immune thrombocytopenic purpura, who developed 5 years later an ecchymotic syndrome despite normal platelet count. High bleeding time and platelet aggregation defect in vitro were evidenced. Following the initial thrombocytopenia, anti-glycoproteins GPIIb/IIIa with lupus anticoagulant and benign monoclonal gammapathy were noticed. Platelet controls showed that hypoaggregant activity was secondary to the persistence of anti-GPIIb/IIa antibodies. CONCLUSION: This acquired auto-immune thrombopathy simulating Glanzmann's thrombasthenia was secondary to the persistence of platelet anti-glycoproteins GPIIb/IIIa.