Abstract
We present a new R&D investment function in a Cournot competition model inspired in the logistic equation. We do a full characterization of the associated game and study the short- and long-term economical effects derived from using this new R&D investment function. In particular, we find the existence of regions with multiple Nash investment equilibria. For low production costs, that can correspond to the production of old technologies, the long-term economical effects are not very sensitive to small changes in the efficiency of the R&D programmes neither to small changes in the market structure. However, for high production costs, that can correspond to the production of new technologies, the long-term economical effects are very sensitive to small changes in the efficiency of the R&D programmes and also to small changes in the market structure.

Abstract
The von Mises-Fisher distribution is widely used for modeling directional data. In this article, we derive the discriminant rules based on this distribution to assign objects into pre-existing classes. We determine a distance between two von Mises-Fisher populations and we calculate estimates of the misclassification probabilities. We also analyze the behavior of the distance between two von Mises-Fisher populations and of the estimates of the misclassification probabilities when we modify the parameters of the populations or the samples size or the dimension of the sphere. Finally, we present an example with real spherical data available in the literature.

Abstract
The Watson distribution is one of the most used distributions for modeling axial data. In some situations, it is important to investigate if several Watson populations differ significantly. In this paper, we develop likelihood ratio tests and the ANOVA for testing the hypothesis of the equality of the directional parameters of several Watson distributions with different concentrations. We also determine the empirical power of the ANOVA and LR tests for some dimensions of the sphere.

Abstract
Background and aims: For several decades, psychological characteristics associated to obesity have been discussed, and it is important to know them as they could influence the development of the disease. Aim of this study was to describe psychological characteristics of an obese sample using psychometric self-evaluation, to compare psychological characteristics between sexes, between those who had and those who had not already tried to lose weight, and to evaluate the association between psychological parameters and age, education level, current BMI, desired weight BMI and BMI they wished to lose. Methods: An evaluation was carried on 261 females and 48 males (40.9 +/- 13.4; 52.0 +/- 11.3 years), overweight (BMI >= 25.0 kg/m(2)). Psychological characteristics were studied using Hopkins Symptom Distress Checklist 90 revised (SCL-90-R) (direct administration). Results: More than half of females obtained results indicating psychological distress (>1.5) in scales somatization (SOM), obsessive/compulsive (OBS), depression (DEP) and paranoid ideation (PAR). More than 40% of males had >1.5 points in SOM, OBS and PAR. Females showed significantly higher points in 9 subscales, and in positive symptom distress index (PSDI). Females who have tried to lose weight only showed a significantly higher SOM. Both male groups, who have tried to lose weight or not, were similar in the different subscales and in the PSDI. Older and less educated females had higher points in SOM/OBS/DEP/Phobic Anxiety/PSDI. Females with a higher BMI had significantly higher results in SOM/OBS/Interpersonal Sensitivity (IPS)/DEP/PSDI. There were no correlations in males between age or BMI and psychopathological evaluation. However, the lower the level of education the higher the points in SOM/OBS/IPS/Anxiety (ANX)/PAR/Psychoticism (PSY). Conclusions: Psychometric evaluation does not allow clinical diagnostics to be made, but our data suggest potential psychological symptoms in this obese sample. These symptoms seem to be more prevalent and intense in females and seem to be higher in older females, with higher BMI and less educated patients. Obesity and Metabolism 2009; 5: 78-85.

Abstract
Those who work in obesity treatment know that long term success is hard to achieve. The reasons for non compliance in diet therapies are not well understood. In this study, we tried to recognize difficulties and barriers linked to unsuccessful weight reduction. This study was conducted in an outpatient clinic of a central university hospital. 442 overweight patients (371 women and 71 men), with BMI >= 25 kg/m(2), were enquired about diet compliance: a) existence of difficulties; b) difficulty degree (five point scale); 0 barriers of diet therapy (close-ended options). Mean age was 41 years, with SD 13 years. More than half patients mentioned difficulties in the diet maintenance. When asked about the difficulty degree, almost all patients mentioned at least some difficulty with degree 3 "quite difficult" being the most common answer The top five barriers were similar for both genders, but they were differently ranked. Women seem to give more importance to psychological issues. Most overweight patients feel barriers in the compliance of their diet therapy. Although a similar proportion of males and females referred difficulties and similar difficulty degrees regarding their diet therapy, the main difficulty, came from different origins. This enhances the importance of establishing an individual food plan respecting sensorial properties and social environment, together with the patient's habits, psychological condition and motivation, as a way to encourage diet compliance and to achieve success in obesity treatment. Obesity and Metabolism 2009; 5: 107-113.

Abstract
In this paper, we consider the single machine scheduling problem with linear earliness and quadratic tardiness costs. and no machine idle time. We propose a genetic approach based on a random key alphabet. Several genetic algorithms based on this approach are presented. These versions differ on the generation of the initial population, as well as on the use of local search. The proposed procedures are compared with existing heuristics, as well as with optimal solutions for the smaller instance sizes. The computational results show that the performance of the proposed genetic approach is improved by the addition of a local search procedure, as well as by the insertion of simple heuristic solutions in the initial population. Indeed, the genetic versions that include either or both of these features not only provide significantly better results, but are also much faster. The genetic versions that use local search are clearly superior to the existing heuristics, and the improvement in performance over the best existing procedure increases with both the size and difficulty of the instances. These genetic procedures are also quite close to the optimum, and provided an optimal solution for most of the test instances.