Coffee, Alcohol, Smoking, Physical Activity and QT Interval Duration: Results from the Third National Health and Nutrition Examination Survey

Abnormalities in the electrocardiographic QT interval duration have been associated with an increased risk of ventricular arrhythmias and sudden cardiac death. However, there is substantial uncertainty about the effect of modifiable factors such as coffee intake, cigarette smoking, alcohol consumption, and physical activity on QT interval duration.We studied 7795 men and women from the Third National Health and Nutrition Survey (NHANES III, 1988-1994). Baseline QT interval was measured from the standard 12-lead electrocardiogram. Coffee and tea intake, alcohol consumption, leisure-time physical activities over the past month, and lifetime smoking habits were determined using validated questionnaires during the home interview.In the fully adjusted model, the average differences in QT interval comparing participants drinking ≥6 cups/day to those who did not drink any were -1.2 ms (95% CI -4.4 to 2.0) for coffee, and -2.0 ms (-11.2 to 7.3) for tea, respectively. The average differences in QT interval duration comparing current to never smokers was 1.2 ms (-0.6 to 2.9) while the average difference in QT interval duration comparing participants drinking ≥7 drinks/week to non-drinkers was 1.8 ms (-0.5 to 4.0). The age, race/ethnicity, and RR-interval adjusted differences in average QT interval duration comparing men with binge drinking episodes to non-drinkers or drinkers without binge drinking were 2.8 ms (0.4 to 5.3) and 4.0 ms (1.6 to 6.4), respectively. The corresponding differences in women were 1.1 (-2.9 to 5.2) and 1.7 ms (-2.3 to 5.7). Finally, the average differences in QT interval comparing the highest vs. the lowest categories of total physical activity was -0.8 ms (-3.0 to 1.4).Binge drinking was associated with longer QT interval in men but not in women. QT interval duration was not associated with other modifiable factors including coffee and tea intake, smoking, and physical activity

Exploiting damped techniques for nonlinear conjugate gradient methods

In this paper we propose the use of damped techniques within Nonlinear Conjugate Gradient (NCG) methods. Damped techniques were introduced by Powell and recently reproposed by Al-Baali and till now, only applied in the framework of quasi–Newton methods. We extend their use to NCG methods in large scale unconstrained optimization, aiming at possibly improving the efficiency and the robustness of the latter methods, especially when solving difficult problems. We consider both unpreconditioned and Preconditioned NCG (PNCG). In the latter case, we embed damped techniques within a class of preconditioners based on quasi–Newton updates. Our purpose is to possibly provide efficient preconditioners which approximate, in some sense, the inverse of the Hessian matrix, while still preserving information provided by the secant equation or some of its modifications. The results of an extensive numerical experience highlights that the proposed approach is quite promising

Models for solving the tariff optimization problem

We present the methods of telecommunication tariff optimization from a point of client’s view. A client which wants to minimize his monthly fees tries to choose a proper tariff model. In case of large companies these models are more complicated and the optimization models should be used. We describe a simple MIP models and their modifications solved with CLP solvers. All the examples were solved with ILOG and ECLiPSe MIP and CLP solvers

Optymalizacja wielokryterialna skorygowaną metodą PSO na przykładzie procesu skrawania stali 18CrMo4 w stanie zahartowanym

W pracy zaproponowano zmodyfikowaną metodę optymalizacji wielocząsteczkowej (PSO) dla problemów optymalizacji wielokryterialnej z dyskretną przestrzenią decyzyjną. W metodzie PSO zmieniono sposób określania momentu bezwładności, współczynnika uczenia oraz współczynnika społecznego. Dodatkowo wprowadzono elitaryzm oraz innowacyjny mechanizm hamowania cząstek chroniący je przed przekraczaniem dopuszczalnych granic przestrzeni decyzyjnej. Zaproponowane podejście zostało zweryfikowane na szeregu aktualnych funkcjach testowych oraz problemie optymalizacji procesu skrawania stali 18CrMo4 w stanie zahartowanym, gdzie porównano je z wynikami uzyskanymi za pomocą algorytmów genetycznych (GA). Uzyskane wyniki wskazują, że zaproponowane podejście jest względnie szybkie i wysoce konkurencyjne w stosunku do innych metod optymalizacji. Autorzy uzyskali bardzo różnorodne, zbieżne i w pełnym zakresie przebiegi frontu Pareto w przestrzeni kryteriów. W celu oceny jakości wygenerowanego zbioru Pareto dla każdego z prezentowanych przykładów wyznaczono ocenę opartą na pomiarze entropii oraz wskaźnika jakości IGD.In this paper a Modified Particle Swarm Optimization (PSO) method for multi-objective (MO) problems with a discrete decision space is proposed. In the PSO method the procedure to determine inertia weight, learning factor and social factor is modified. In addition, both an elitism strategy and innovative deceleration mechanism preventing the particles from going beyond the limits of decision space are introduced. The proposed approach has been applied to a series of currently used test functions as well as to optimization problems connected with finish hard turning operation, where the obtained results have been compared with those obtained by means of Genetic Algorithms (GA). The results indicate that the proposed approach is relatively quick, and thus it is highly competitive with other optimization methods. The authors have obtained a very good diversity, convergence and a maximum range of the Pareto front in the criteria space. In order to assess the quality of the generated Pareto set for each of presented examples, a rating has been determined based on the entropy measurement and inverted generational distance (IGD)

Models For Solving The Tariff Optimization Problem

We present the methods of telecommunication tariff optimization from a point of client’s view. A client which wants to minimize his monthly fees tries to choose a proper tariff model. In case of large companies these models are more complicated and the optimization models should be used. We describe a simple MIP models and their modifications solved with CLP solvers. All the examples were solved with ILOG and ECLiPSe MIP and CLP solvers

Launching New IT Product Into the Market

Bringing a new IT product onto the market possess a high business risk due to two main factors: lifetime of an IT product is usually short; IT market is very competitive one. Product success depends on many mutually linked factors and very often the relations among them are difficult to grasp by business analysts. In the paper we present the System Dynamics model describing some important factors which should be analyzed before bringing a new IT product onto the market. We assume that an IT product is maintained within an outsourcing model by other company which uses a cloud computing for that purpose. Our study embraces analysis of the pricing policy of product and that takes into account opponents in the market. We also consider possible modifications of IT product configurations, outsourcing scope and the modification of marketing policy depending on actual IT product parameters. While building the model presented in the paper, contrary to other models in literature, we have used only parameters which can be estimated precisely. By sticking to this attitude we have obtained the model which is more useful than other models presented in the literature on the subject. We present simulation results of the dynamic model for different simulation scenarios resulting from different policies of bringing a new product onto the market

Optimization of sugar dispatching proces

We consider the sugar dispatching process at a sugar mill. The main goal of our work was to check an efficiency of the logistics system in the mill, find and correct the bottlenecks. Some methods for logistics processes optimization are presented. We base on the heuristics and CLP techniques for solving the scheduling problems. Some additional remarks about possibility of using the optimization methods in scheduling and logistics optimizations are presented too