Have CAFE Standards Reduced the Effect of Gasoline Prices on Domestic Automobile Manufacturers’ Market Share of the US Market?

One of macroeconomists’ major concerns is GDP volatility, and understanding what causes this volatility is essential when attempting to reduce it. For decades, the automotive industry has been a major component of US GDP. Therefore, understanding the driving forces behind this industry indirectly contributes to the study of GDP volatility. This paper focuses on CAFE standards and how they change the effect of oil prices on US automobile sales. What motivates this paper is the fact that during the mid-to-late 80s, fluctuations in the market share of domestic automobile manufacturers diminished substantially. Figure 1 presents the sales of domestic automakers’ automobiles as a fraction of the domestic market (market share) from January 1974 to June 2004. One can easily notice that around month 170, which corresponds to February 1988, there is a dramatic decrease in volatility. What could be the cause in the decrease of this volatility? [excerpt

Extreme Value Theory and Value at Risk : Application to Oil Market

Recent increases in energy prices, especially oil prices, have become a principal concern for consumers, corporations, and governments. Most analysts believe that oil price fluctuations have considerable consequences on economic activity. Oil markets have become relatively free, resulting in a high degree of oil-price volatility and generating radical changes to world energy and oil industries. As a result oil markets are naturally vulnerable to significant negative volatility. An example of such a case is the oil embargo crisis of 1973. In this newly created climate, protection against market risk has become a necessity. Value at Risk (VaR) measures risk exposure at a given probability level and is very important for risk management. Appealing aspects of Extreme Value Theory (EVT) have made convincing arguments for its use in managing energy price risks. In this paper, we apply both unconditional and conditional EVT models to forecast Value at Risk. These models are compared to the performances of other well-known modelling techniques, such as GARCH, historical simulation and Filtered Historical Simulation. Both conditional EVT and Filtered Historical Simulation procedures offer a major improvement over the parametric methods. Furthermore, GARCH(1, 1)-t model may provide equally good results, as well as the combining of the two procedures.Extreme Value Theory, Value at Risk, oil price volatility, GARCH, Historical Simulation, Filtered Historical Simulation.

Optimizing Sustainable Transit Bus Networks in Smart Cities

Urban mobility has been facing several challenges in the recent years due to the increasing populations and private vehicles ownership, which led to several negative environmental and social impacts in big cities. In this dissertation, we investigate how decision support systems can enhance the role of transit bus networks in the transition to more sustainable and convenient urban mobility

Using Mobile Devices to Access Social Media Networks: Students Learning through Web Quest Technique

This study aims to explore the effect of mobile devices and social media networks supported with Web Quest on student’s communication and motivation skills. A web Quest was used for implementing the study as a way that enables learners to research on the web to navigate digital learning materials. This study presents the findings on students’ perspectives when searching the social media networks via their mobile devices following the Web Quest steps for achieving learning activities. The study follows the qualitative approach, the student’s used mobile devices to accomplish the learning tasks. The data were collected through a student questionnaire. The findings indicated that the use of mobile devices and social media networks provided opportunities for engaging in learning and increased students’ cooperation. The results also indicated that students enjoyed and appreciated the Web Quest technique. Additionally, students recognized the importance of using mobile devices as tools for education purposes, and acquired the values of group collaboration

LYOPHILIZATION OF SOLID LIPID NANOPARTICLES FOR BRAIN TARGETING

Objective: The aim of this work is to investigate formulation and process parameters that could impact freeze drying of loperamide-loaded Solid Lipid Nanoparticles (Loperamide loaded SLN).Methods: Loperamide loaded SLN was prepared by high shear homogenization method and freeze dried in vials without and with different types and concentrations of cryoprotectants (lactose, glucose, mannitol and povidon) using pilot freeze dryer.Results: The best result has been obtained by using 5 % of monosaccharide glucose solution, although Nanoparticles size has been increased 6 folds. However, the total concentration of loperamide hydrochloride (Loperamide HCl) remained unchanged after freeze drying. It has been found that the type and ratio of surfactants adsorbed at the surface of SLN have impact on the success of the drying process.Conclusion: Results revealed that polymeric nanoparticles could withstand freeze drying stress more than SLN because polymers have higher mechanical resistance in comparison with waxes and lipids.Â

VERS LA CONSTRUCTION D'UN MODELE DE LA COMPETENCE BASE SUR L'IN-SITU : CAS DE LA SNCF

International audienceL'objectif de ce papier est d'essayer de construire un modèle de la compétence basé sur la théorie de l'action située et de la cognition distribuée. Pour ce faire une enquête ethnométhodologique a été menée auprès des agents en contact avec la clientèle (ACC) de la SNCF. Les résultats montrent que la compétence émergente dans la relation de service ne peut être appréhendée qu'en et dans la situation. Dit autrement, le modèle de la compétence n'est valable qu'n prenant en compte les variables identifiées in-situ