Nonminimal Inflation on the Randall-Sundrum II Brane with Induced Gravity

We study an inflation model that inflaton field is non-minimally coupled to the induced scalar curvature on the Randall-Sundrum (RS) II brane. We investigate the effects of the non-minimal coupling on the inflationary dynamics of this braneworld model. Our study shows that the number of e-folds decreases by increasing the value of the non-minimal coupling. We compare our model parameters with the minimal case and also with recent observational data. In comparison with recent observation, we obtain a constraint on the values that the non-minimal coupling attains.Comment: 15 pages, 5 figure

NAFTA and the Mexican Economy

The North American Free Trade Agreement (NAFTA), in effect since January 1994, plays a very strong role in the bilateral economic relationship between Mexico and the United States. The two countries are also closely tied in areas not directly related to trade and investment such as security, environmental, migration, and health issues. The effects of NAFTA on Mexico and the state of the Mexican economy have important impacts on U.S. economic and political interests. As NAFTA approaches its 15th anniversary, a number of policymakers have raised the issue of revisiting NAFTA and renegotiating parts of the agreement. Some important factors in evaluating NAFTA include the effects of the agreement on Mexico and how these relate to U.S.-Mexico economic relations. In the 110th Congress, major issues of concern have been related mostly to economic conditions in Mexico, the effect of NAFTA on the United States and Mexico, and Mexican migrant workers in the United States. In 1990, then Mexican President Carlos Salinas de Gortari approached the United States with the idea of forming a free trade agreement (FTA). Mexico’s main motivation in pursuing an FTA with the United States was to stabilize the Mexican economy by attracting foreign direct investment. The Mexican economy had experienced many difficulties throughout most of the 1980s with a significant deepening of poverty. The intention of Mexico in entering NAFTA was to increase export diversification by attracting foreign direct investment (FDI), which would help create jobs, increase wage rates, and reduce poverty. At the time that NAFTA went into effect, the expectation among supporters was that the agreement would improve investor confidence in Mexico, attract investment, and narrow the income differentials between Mexico and the United States and Canada. Measuring the effects of NAFTA on the Mexican economy is difficult because the economy was also affected by other factors, such as economic cycles in the United States (Mexico’s largest trading partner) and currency fluctuations. In addition, Mexico’s unilateral trade liberalization measures of the 1980s and the currency crisis of 1995 both affected economic growth, per capita gross domestic product (GDP), and real wages. While NAFTA may have brought economic and social benefits to the Mexican economy as a whole, the benefits have not been evenly distributed throughout the country. Wages and employment tend to be higher in states experiencing higher levels of FDI and trade. The agricultural sector experienced a higher amount of worker displacement after NAFTA because of increased competition from the United States and because of Mexican domestic agricultural reforms. In terms of regional effects, initial conditions in Mexico determined which Mexican states experienced stronger economic growth as a result of NAFTA. States with higher levels of telecommunications and transportation infrastructure gained more benefits than poorer states with lower levels of education, infrastructure, and institutional capacity. Some economists argue that while trade liberalization may narrow income disparities over the long run with other countries, it may indirectly lead to larger disparities in income levels within a country. This report will be updated as events warrant

The feminine face of Science

Uno de los objetivos fijados en la asignatura Ciencias para el mundo contemporáneo (1º de Bachillerato) es el de superar el escaso interés que siente el alumnado hacia la ciencia. Es necesario para tal fin un cambio en los planteamientos tanto metodológicos como temáticos, respecto a las asignaturas de ciencias tradicionales. Con la intención de contribuir a este cambio se han diseñado actividades en las que confluyen características que podrán ayudar a conseguirlo. En el caso propuesto se escogió una temática controvertida a lo largo de la historia: Mujeres y Ciencia; eligiendo como estrategia de aprendizaje las webquests y publicando en la red las tareas realizadas por el alumnado, todo esto con la finalidad de romper las paredes del aula y hacer extensiva la cultura científica al resto de la comunidad educativa y público en general

THREE-DIMENSIONAL DYNAMIC ANALYSIS OF POLE VAULTING

INTRODUCTION'-The pole vault is one of the most exciting track and field event. Thus, many mechanical studies have been carried out in order to provide useful information to pole vault coaches and athletes. But, only Barlow (1979) then Gros (1982) realised a dynamic experimental study in two dimensions : they used force transducers to measure the reaction force of the vaulting box. The main contribution of our study is the 3-D approach of the dynamic analysis and the direct measurement of the impulse at the last step before taking off. Two force plates created in our laboratory were used 10 record reaction forces of pole vault trials. The acquisition frequency was 500 Hz. A first force plate put under the pole vault box provided the reaction force acting on the lip of the pole in the three dimensions of the space. Then, a second force plate of the same conception but bigger was fixed under the runway for the measurement of the reaction force at the last touchdown of the foot before the take-off. The both force plates were synchronised using an external electric signal. Such an experimental system allows to compute the total impulse of the system pole-athlete throughout the vault. RESULTS • Before analysing the experimental results, we have filtered the three components of the reaction forces (Fx, Fy, Fz) so as to eliminate the own frequency of the force plates. The knowledge of the dynamics of pole vaulting is necessary for a better understanding of that athletic movement!. Indeed, the simultaneous analysis of the force spelling at the last touchdown of the foot with the runway and of the force applied in the box allows to characterise precisely different events of the v8ult: du ration of the last contact of the foot with the track, impulse al taking-off, time spend between the impact of the tip of the pole in the box and the last touchdown of the foot ... Furthermore, after taking-off, the vaulter contacts the ground through the pole, so a detailed analysis of the reaction force of the vaulting box shows the main phases of a pole vault trials : impact, take-off and rockback, pull-up and turnover and pole release. CONCLUSION • This experimental dynamic system is indispensable in understanding the main phases of pole vaulting and could be a powerful way to improve performances. Nevertheless, that research must be undertaken in collaboration with pole vaulters and coaches because the results will be applied by athletes. Moreover, a program of experimental analysis of pole vaulting has been lead in our laboratory for few years. The dynamic study is also completed with a 3-D cinematographic analysis. Indeed, such a system could allow the measurement or computation of all the mechanical parameters in\l.0lved in pole vaulting and the experimental results could provide to numerical simulations the variation of all the mechanical parameters in order to make them much closer to reality. REFERENCES J. Morlier and M. eid. "Analyse mecanique 3-D du saut ä la perehe". XII French meeting of Mechanics at Strasbourg from the 4th to the 8th of September 1995. J. Morlier and M. Cid. "Three-dimensional analysis of the angular momentum of a pole vaulter". To be published in Journal Of Biomechanics

Topological defects and misfit strain in magnetic stripe domains of lateral multilayers with perpendicular magnetic anisotropy

Stripe domains are studied in perpendicular magnetic anisotropy films nanostructured with a periodic thickness modulation that induces the lateral modulation of both stripe periods and inplane magnetization. The resulting system is the 2D equivalent of a strained superlattice with properties controlled by interfacial misfit strain within the magnetic stripe structure and shape anisotropy. This allows us to observe, experimentally for the first time, the continuous structural transformation of a grain boundary in this 2D magnetic crystal in the whole angular range. The magnetization reversal process can be tailored through the effect of misfit strain due to the coupling between disclinations in the magnetic stripe pattern and domain walls in the in-plane magnetization configuration