Modelamiento de diversos factores que inciden en el rendimiento académico de los estudiantes de física de la Universidad de Nariño en el semestre A-2017

Este trabajo tiene como objetivo identificar factores relacionados con el desempeño académico de los estudiantes de Física de la Universidad de Nariño, y hacer uso de estos, mediante métodos estadísticos para buscar relaciones entre dichas variables y así proponer un modelo que explique en buena medida el desempeño académico de la población mencionada. El estudio incluye breves antecedentes tomados de anteriores investigaciones afines; algunas de las cuales fueron realizadas también en la Universidad de Nariño, otros trabajos realizados en el exterior y dan una idea de la problemática que guarda esta situación en varias naciones, posteriormente se presenta la metodología seguida en la investigación, los resultados estadísticos obtenidos, su discusión y las conclusiones del presente, para finalmente listar las referencias bibliográficas utilizadas en el estudio

Noisy metrology beyond the standard quantum limit

Parameter estimation is of fundamental importance in areas from atomic spectroscopy and atomic clocks to gravitational wave detection. Entangled probes provide a significant precision gain over classical strategies in the absence of noise. However, recent results seem to indicate that any small amount of realistic noise restricts the advantage of quantum strategies to an improvement by at most a multiplicative constant. Here, we identify a relevant scenario in which one can overcome this restriction and attain superclassical precision scaling even in the presence of uncorrelated noise. We show that precision can be significantly enhanced when the noise is concentrated along some spatial direction, while the Hamiltonian governing the evolution which depends on the parameter to be estimated can be engineered to point along a different direction. In the case of perpendicular orientation, we find superclassical scaling and identify a state which achieves the optimum.Comment: Erroneous expressions with inconsistent units have been corrected. 5 pages, 3 figures + Appendi

Strengthening Soil Databases for Climate Change and Food Security Modeling Applications

Climate change is a hazard to the food security of a growing world population since it affects agriculture and likewise, agriculture and natural resource management affect the climate system. The relationships between all these factors including polices, political conditions, economical management and pest and diseases, and how they interact are not currently well-understood, nor are the advantages and disadvantages of different responses to climate change. In the face of climate change it is important to integrate knowledge about it to generate realistic solutions for agriculture, and food security in a meaningful and innovative way. Research in this topic has focused on addressing the needs for methods, models, databases and system metrics aimed at enhanced assessment and improved methodologies for the impact of climate change on agricultural systems and the development of different policy and program interventions to foster adaptation and mitigation in terms of poverty alleviation, food security and environmental health. This work should be in a framework and set of modeling tools and databases to analyze the implications of human responses to the climate challenge in terms of regional food security and the preservation of important ecosystem services, upon which the long-term sustainability of global agriculture must be based

Electrostatics of electron-hole interactions in van der Waals heterostructures

The role of dielectric screening of electron-hole interaction in van der Waals heterostructures is theoretically investigated. A comparison between models available in the literature for describing these interactions is made and the limitations of these approaches are discussed. A simple numerical solution of Poissons equation for a stack of dielectric slabs based on a transfer matrix method is developed, enabling the calculation of the electron-hole interaction potential at very low computational cost and with reasonable accuracy. Using different potential models, direct and indirect exciton binding energies in these systems are calculated within Wannier-Mott theory, and a comparison of theoretical results with recent experiments on excitons in two-dimensional materials is discussed.Comment: 10 pages, 8 figure