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Colima, Mexico

The University of Colima is a Mexican public university with several campuses across the state of Colima, bordering the Pacific Ocean. It was created on September 16, 1940 by the President Lázaro Cárdenas as People's University of Colima , and intended to serve the educational needs of the Michoacán, Jalisco, and Colima.The University's library system holds over 93,127 volumes. Wikipedia.

Amore P.,University of Colima
Annals of Physics | Year: 2011

We analyze the problem of calculating the solutions and the spectrum of a string with arbitrary density and fixed ends. We build a perturbative scheme which uses a basis of WKB-type functions and obtain explicit expressions for the eigenvalues and eigenfunctions of the string. Using this approach we show that it is possible to derive the asymptotic (high energy) behavior of the string, obtaining explicit expressions for the first three coefficients (the first two can also be obtained with the WKB method). Finally, using an iterative approach we also obtain analytical expressions for the low energy behavior of the eigenvalues and eigenfunctions of a string with rapidly oscillating density, recovering (in a simpler way) results in the literature. © 2011 Elsevier Inc. Source

Hofmann C.P.,University of Colima
Physical Review B - Condensed Matter and Materials Physics | Year: 2012

Within the effective Lagrangian framework, we explicitly evaluate the partition function of two-dimensional ideal ferromagnets up to three loops at low temperatures and in the presence of a weak external magnetic field. The low-temperature series for the free energy density, energy density, heat capacity, entropy density, and magnetization are given and their range of validity is critically examined in view of the Mermin-Wagner theorem. The calculation involves the renormalization and numerical evaluation of a particular three-loop graph, which is discussed in detail. Interestingly, in the low-temperature series for the two-dimensional ideal ferromagnet, the spin-wave interaction manifests itself in the form of logarithmic terms. In the free energy density the leading such term is of order T4lnT: remarkably, in the case of the three-dimensional ideal ferromagnet no logarithmic terms arise in the low-temperature series. While the present study demonstrates that it is straightforward to consider effects up to three-loop order in the effective field theory framework, this precision seems to be far beyond the reach of microscopic methods such as spin-wave theory. © 2012 American Physical Society. Source

James M.R.,Lancaster University | Varley N.,University of Colima
Geophysical Research Letters | Year: 2012

Monitoring the topography of active lava domes is critical for detecting changes that may trigger or influence collapse or explosive activity. Internal dome structure and conditions are more difficult to elucidate, but also play vital roles. Here, we describe the exposure (following an explosion) of significant scarps in the active dome at Volcn de Colima, Mexico, that are interpreted as evidence of brittle failure planes and a complex internal dome morphology. In the first use of automated 3D computer vision reconstruction techniques (structure-from-motion and multi-view stereo, SfM-MVS) on an active volcanic dome, we derive high resolution surface models from oblique and archive photographs taken with a consumer camera. The resulting 3D models were geo-referenced using features identified in a web-sourced orthoimage; no ground-based measurements were required. In December 2010, the dome (2.14 × 106 m3) had a flat upper surface, reflecting an overall ductile emplacement regime. Between then and May 2011, a period of low explosivity was accompanied by a small volume loss (0.4 × 105 m3) and arcuate steps appeared in the dome surface, suggesting the presence of localized planes of weakness. The complex array of summit scarps was exposed following a significant explosion in June 2011, and is interpreted to be the surface expression of fault planes in the dome. The 1-m resolution DEMs indicated that the region of greatest volume loss was not coincident with the assumed location of the conduit, and that heterogeneity within the dome may have been important during the June explosion. © 2012. American Geophysical Union. All Rights Reserved. Source

Hofmann C.P.,University of Colima
Physical Review B - Condensed Matter and Materials Physics | Year: 2013

The thermodynamic properties of ferromagnetic spin chains have been analyzed with a variety of microscopic methods over the years: Bethe ansatz, spin-wave theory, Schwinger-boson mean-field theory, Green functions, and renormalization group methods. Surprisingly, in all these different studies, the manifestation of the spin-wave interaction in the low-temperature series for the thermodynamic quantities, in the presence of a finite magnetic field, has been largely neglected. In the present work, we address this problem by following a different path, based on the systematic effective Lagrangian method. We evaluate the partition function up to two-loop order and derive the low-temperature expansion of the energy density, entropy density, heat capacity, magnetization, and susceptibility in the presence of a weak external magnetic field. Remarkably, the spin-wave interaction only manifests itself beyond two-loop order. In particular, there is no term of order T2 in the low-temperature series of the free energy density. This is the analog of Dyson's statement that there is no term of order T4 in the low-temperature series of the free energy density in the case of three-dimensional ideal ferromagnets. The range of validity of our series is critically examined in view of the nonperturbatively generated energy gap. We also compare our results with the condensed matter literature and point out that there are some misleading statements. © 2013 American Physical Society. Source

Gonzalez-Perez O.,University of Colima | Alvarez-Buylla A.,University of California at San Francisco
Brain Research Reviews | Year: 2011

Demyelinating diseases are characterized by an extensive loss of oligodendrocytes and myelin sheaths from axolemma. These neurological disorders are a common cause of disability in young adults, but so far, there is no effective treatment against them. It has been suggested that neural stem cells (NSCs) may play an important role in brain repair therapies. NSCs in the adult subventricular zone (SVZ), also known as Type-B cells, are multipotential cells that can self-renew and give rise to neurons and glia. Recent findings have shown that cells derived from SVZ Type-B cells actively respond to epidermal-growth-factor (EGF) stimulation becoming highly migratory and proliferative. Interestingly, a subpopulation of these EGF-activated cells expresses markers of oligodendrocyte precursor cells (OPCs). When EGF administration is removed, SVZ-derived OPCs differentiate into myelinating and pre-myelinating oligodendrocytes in the white matter tracts of corpus callosum, fimbria fornix and striatum. In the presence of a demyelinating lesion, OPCs derived from EGF-stimulated SVZ progenitors contribute to myelin repair. Given their high migratory potential and their ability to differentiate into myelin-forming cells, SVZ NSCs represent an important endogenous source of OPCs for preserving the oligodendrocyte population in the white matter and for the repair of demyelinating injuries. © 2010 Elsevier B.V. Source

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