Spontaneous Symmetry Breakdown in non-relativistic Quantum Mechanics

The advantages and disadvantages of some pedagogical non-relativistic quantum-mechanical models, used to illustrate spontaneous symmetry breakdown, are discussed. A simple quantum-mechanical toy model (a spinor on the line, subject to a magnetostatic interaction) is presented, that exhibits the spontaneous breakdown of an internal symmetry.Comment: 19 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1111.1213. Equations (30) and (31) have been corrected. Other minor correction

Perception of the environment for walking according the locality in Barranquilla, Colombia.

El objetivo fue estimar la percepción del ambiente del barrio para caminar según la localidad de la ciudad. Se realizó un estudio descriptivo transversal en 2103 personas entre 15 y 69 años de edad. Se aplicó el Cuestionario Internacional de Actividad Física (IPAQ), y el Módulo Ambiente del International Physical Activity Study. Se estimó la asociación entre la percepción de los atributos del barrio y la localidad donde reside la persona. Los residentes del sur de la ciudad tienen mayor riego de percibir pocos supermercados a poca distancia de sus casas [OR 1,29(IC 95% 1,10-1,65)], aceras en mal estado [OR 1,44(IC 95% 1,10-1,90)], pocas personas físicamente activas [OR 4,13(IC 95% 2,50-6,82)], peligro para pasear durante el día[OR 3,07(IC 95% 1,96-4,80)], y pocas cosas interesantes en el vecindario [OR 3,21(IC 95% 2,05-5,02)]The objective was to estimate the perception of the neighborhood environment for walking according to the location of the city. A cross-sectional descriptive study was performed in 2103 people aged 15 to 69 years of age. We applied the International Physical Activity Questionnaire (IPAQ) and the Environment Module of the International Physical Activity Study. We estimated the association between perceived attributes of the neighborhood and the locality where the person lives. The residents of the South of the city have a higher risk of perceiving a few supermarkets within walking distance of their homes [OR 1,29 (95% CI 1,10-1,65)], presence of sidewalks in bad condition [OR 1,44 (95% CI 1,10-1,90)], few people physically active [OR 4,13 (95% CI 2,50-6,82)], danger to stroll during the day [OR 3,07 (95% CI 1,96-4,80)] and few interesting things in the neighborhood [OR 3,21 (95% CI 2,05-5,02)

In vitro propagation of cedar (Cedrela odorata L.) from juvenile shoots

Garriga, M (Garriga, Miguel); Caligari, PDS (Caligari, Peter D. S.). Univ Talca, Inst Biol Vegetal & Biotecnol, Talca, ChileCedrela odorata L. is one of the most important timber species currently traded in the Caribbean and Central America; however, it has been intensively exploited. In vitro techniques and clonal propagation can help to develop new plantations and assist in establishing improvement programs for this species. The aim of this study was to develop a protocol to establish in vitro conditions and to micropropagate this species from nodal explants from juvenile cuttings taken from field trees. Disinfection of node explants with 5% propiconazole CE 25 during 3 min resulted in 100% explant disinfection and 60% morphogenic response on those established explants. Shoot development was optimized by cultivating in vitro node explants in Murashige and Skoog basal medium supplemented with 2 mg L(-1) 6-bencilaminopurine and 3 mg L(-1) naphthaleneacetic acid. This medium resulted in 100% shoot development from the in vitro node explants with a 3.93 cm mean height. Rooting was also stimulated 6 wk after individualization of the regenerated plants on the same micropropagation medium with a mean of 3.9 roots per plant. In vitro plants did not show morphologic differences when compared to ex vitro seeds

Cartilla para promover la interculturalidad en la escuela : costa norte

Expone diversos aspectos referidos a la migración, folklore, conservación del medio ambiente entre otros temas relacionados a esa zona del país

Dinámica territorial urbana en el Estado de Oaxaca 1950-2000

El trabajo aborda las transformaciones que acontecen en la estructura territorial del estado de Oaxaca, mediante el análisis del proceso de urbanización de las localidades urbanas, el diferente grado de urbanización de los municipios a los cuales corresponden y las variaciones en tamaño, crecimiento y concentración de población de las ciudades en esa entidad federativa

Dinámica territorial urbana en el Estado de Oaxaca 1950-2000

El trabajo aborda las transformaciones que acontecen en la estructura territorial del estado de Oaxaca, mediante el análisis del proceso de urbanización de las localidades urbanas, el diferente grado de urbanización de los municipios a los cuales corresponden y las variaciones en tamaño, crecimiento y concentración de población de las ciudades en esa entidad federativa

Modernización estatal y respuesta obrera : historia de una derrota

1 archivo PDF (397 páginas)Texto, producto de una larga investigación documental que se inicia en 1984 con el seguimiento de los conflictos laborales en el colectivo de El Cotidiano y que converge con dos proyectos de investigación: el de "Acumulación y lucha de clases: formas de organización y de conciencia", del Área de Análisis Sociológico de la Historia, y el de "Crisis económica, modernización productiva y respuesta obrera: los conflictos obrero patronales", del Programa de Seguimiento de la Realidad Mexicana Actual, del grupo de investigación de El Cotidiano

Transfer/Breakup Modes in the 6He+209Bi Reaction Near and Below the Coulomb Barrier

Reaction products from the interaction of 6He with 209Bi have been measured at energies near the Coulomb barrier. A 4He group of remarkable intensity, which dominates the total reaction cross section, has been observed. The angular distribution of the group suggests that it results primarily from a direct nuclear process. It is likely that this transfer/breakup channel is the doorway state that accounts for the previously observed large sub-barrier fusion enhancement in this system.Comment: 4 pages; 3 figure

Effects of temperature on thick branes and the fermion (quasi-)localization

Following Campos's work [Phys. Rev. Lett. 88, 141602 (2002)], we investigate the effects of temperature on flat, de Sitter (dS), and anti-de Following Campos's work [Phys. Rev. Lett. \textbf{88}, 141602 (2002)], we investigate the effects of temperature on flat, de Sitter (dS), and anti-de Sitter (AdS) thick branes in five-dimensional (5D) warped spacetime, and on the fermion (quasi-)localization. First, in the case of flat brane, when the critical temperature reaches, the solution of the background scalar field and the warp factor is not unique. So the thickness of the flat thick brane is uncertain at the critical value of the temperature parameter, which is found to be lower than the one in flat 5D spacetime. The mass spectra of the fermion Kaluza-Klein (KK) modes are continuous, and there is a series of fermion resonances. The number and lifetime of the resonances are finite and increase with the temperature parameter, but the mass of the resonances decreases with the temperature parameter. Second, in the case of dS brane, we do not find such a critical value of the temperature parameter. The mass spectra of the fermion KK modes are also continuous, and there is a series of fermion resonances. The effects of temperature on resonance number, lifetime, and mass are the same with the case of flat brane. Last, in the case of AdS brane, {the critical value of the temperature parameter can less or greater than the one in the flat 5D spacetime.} The spectra of fermion KK modes are discrete, and the mass of fermion KK modes does not decrease monotonically with increasing temperature parameter.Comment: 24 pages, 15 figures, published versio

Plasma cytokines as potential biomarkers of kidney damage in patients with systemic lupus erythematosus

Background: Systemic lupus erythematosus is a heterogeneous chronic inflammatory autoimmune disorder characterized by an exacerbated expression of cytokines and chemokines in different tissues and organs. Renal involvement is a significant contributor to the morbidity and mortality of systemic lupus erythematosus, and its diagnosis is based on renal biopsy, an invasive procedure with a high risk of complications. Therefore, the development of alternative, non-invasive diagnostic tests for kidney disease in patients with systemic lupus erythematosus is a priority. Aim: To evaluate the plasma levels of a panel of cytokines and chemokines using multiplex xMAP technology in a cohort of Colombian patients with active and inactive systemic lupus erythematosus, and to evaluate their potential as biomarkers of renal involvement. Results: Plasma from 40 systemic lupus erythematosus non-nephritis patients and 80 lupus nephritis patients with different levels of renal involvement were analyzed for 39 cytokines using Luminex xMAP technology. Lupus nephritis patients had significantly increased plasma eotaxin, TNF-a, interleukin-17-a, interleukin-10, and interleukin-15 as compared to the systemic lupus erythematosus non-nephritis group. Macrophage-derived chemokine, growth regulated oncogene alpha, and epidermal growth factor were significantly elevated in systemic lupus erythematosus non-nephritis patients when compared to lupus nephritis individuals. Plasma eotaxin levels allowed a discrimination between systemic lupus erythematosus non-nephritis and lupus nephritis patients, for which we performed a receiver operating characteristic curve to confirm. We observed a correlation of eotaxin levels with active nephritis (Systemic Lupus Erythematosus Disease Activity Index). Our data indicate that circulating cytokines and chemokines could be considered good predictors of renal involvement in individuals with systemic lupus erythematosus