Biogeographic Barriers in the Andes: Is the Amotape—Huancabamba Zone a Dispersal Barrier for Dry Forest Plants?

This is the final version of the article. Available from Missouri Botanical Garden Press via the DOI in this record.We investigate whether the Amotape—Huancabamba zone in the Andes acts as a barrier or corridor for plant species migration. We test this hypothesis based on data on trees, shrubs, and herbs collected in dry inter-Andean valleys (DIAVs) of Ecuador. We found that 72% of the species cross the Amotape—Huancabamba zone in a north—south direction and 13% of the species cross the Andes in an east—west direction. Southern DIAVs concentrate the highest numbers of endemic species. At the regional level we found that 43% of the species are exclusively Andean, while the remaining 57% are found in the Pacific lowlands, the Caribbean, and Mesoamerica. These results showing many species crossing the Amotape—Huancabamba zone in a north—south direction and also frequently found in neighboring lowland and highland ecosystems suggest that the Amotape—Huancabamba zone acts as a corridor for species migration of dry inter-Andean flora.This research was funded by the SENESCYT scholarship “Convocatoria 2011,” the Oticon Foundation, Pontificia Universidad Catolica del Ecuador, and SYNTHESYS research visiting grant 201

La situación de las mujeres indígenas en México

Después de cinco años de lucha, México aprobó la Legislación Indígena. Sin embargo, ésta no cumple con los requisitos mínimos a los que aspiraban las comunidades indígenas, la comunidad de los derechos humanos y los juristas progresistas. En realidad, esta legislación es un grave retroceso, ya que objetivisa a las comunidades indígenas, las despoja de su condición de sujetos de derecho y las convierte en objetos de protección

Anisotropic electron g-factor in quantum dots with spin-orbit interaction

g-factor tuning of electrons in quantum dots is studied as function of in-plane and perpendicular magnetic fields for different confinements. Rashba and Dresselhaus effects are considered, and comparison is made between wide- and narrow-gap materials. The interplay between magnetic fields and intrinsic spin-orbit coupling is analyzed, with two distinct phases found in the spectrum for GaAs in perpendicular field. The anisotropy of the g-factor is reported, and good agreement with available experimental findings is obtained.Comment: 5 pages, 4 figs. (higher resol. figs. under request

Morbidity and Mortality of Newborns with Gastrointestinal Surgical Pathology Admitted to the Neonatology Service of the Vicente Corral Moscoso Hospital

Morbidity and mortality in newborns with gastrointestinal malformations are high, even more so in low- and middle-income countries due to the need for immediate surgical care. However, the literature on these anomalies is scarce in Ecuador. This research aims to increase the registered data on the morbidity and mortality of newborns with gastrointestinal surgical pathology in Cuenca, Ecuador. A descriptive and cross-sectional study was carried out, involving 63 newborns with gastrointestinal surgical pathology admitted to the neonatology service of the Vicente Corral Moscoso Hospital. Data collection was done by reviewing medical records, using a form. The results showed that the mortality rate was higher in 2020. The majority of live newborns had esophageal atresia, they were male, born at term, with middle-aged mothers from urban areas. Of the deceased, the majority had a congenital diaphragmatic hernia, they were children of mothers from rural areas, and half died within 24 hours of being born, mainly from septic shock. In conclusion, the results of this study should not be considered definitive due to the omission of 23 clinical histories; moreover, a low mortality rate is evidenced. It was also observed that they died mainly from septic shock, a preventable cause of mortality from the first level of care with the detection of maternal risk factors. Keywords: morbidity, mortality, malformation, surgical neonate. Resumen Antecedentes: la morbimortalidad en recién nacidos con malformaciones gastrointestinales es elevada, más aún en países de ingresos medios y bajos debido a la necesidad de atención quirúrgica inmediata, sin embargo la literatura sobre estas anomalías es escasa en el Ecuador. Objetivos: incrementar los datos registrados sobre la morbimortalidad de recién nacidos con patología quirúrgica gastrointestinal en Cuenca, Ecuador. Métodos: se realizó un estudio descriptivo y transversal, participaron 63 recién nacidos con patología quirúrgica gastrointestinal ingresados en el servicio de neonatología del Hospital Vicente Corral Mosoco. La recolección de datos se realizó mediante la revisión de historias clínicas, empleando un formulario. Resultados: la tasa de mortalidad fue mayor, en el año 2020. La mayoría de recién nacidos vivos tenían atresia esofágica, eran hombres, nacidos a término, con madres de edad media, procedentes de zonas urbanas. De los fallecidos, la mayoría tenía hernia diafragmática congénita, eran hijos de madres procedentes de zonas rurales, la mitad murió a las 24 horas de nacido, principalmente de shock séptico. Conclusiones: los resultados de este estudio no deben considerarse como definitivos, debido a la omisión de 23 historias clínicas, se evidencia una baja tasa de mortalidad. También se observó que fallecieron principalmente de shock séptico, una causa de mortalidad prevenible desde el primer nivel de atención con la detección de factores de riesgo maternos. Palabras Clave: Morbilidad. Mortalidad. Malformación. Neonato quirúrgico

Dynamics of two interacting particles in classical billiards

The problem of two interacting particles moving in a d-dimensional billiard is considered here. A suitable coordinate transformation leads to the problem of a particle in an unconventional hyperbilliard. A dynamical map can be readily constructed for this general system, which greatly simplifies calculations. As a particular example, we consider two identical particles interacting through a screened Coulomb potential in a one-dimensional billiard. We find that the screening plays an important role in the dynamical behavior of the system and only in the limit of vanishing screening length can the particles be considered as bouncing balls. For more general screening and energy values, the system presents strong non-integrability with resonant islands of stability.Comment: REVTEX manuscript, 4 figures (1 ps + 3 gif, Postscript versions available upon request). Also available at http://www.phy.ohiou.edu/~ulloa/ulloa.htm