Vorobiev Y.M.,University of Sonora
Physics of Atomic Nuclei | Year: 2011
Using the averaging procedure for Poisson brackets, we study the nonadiabatic dynamics of perturbed Hamiltonian systems on slow-fast S1 spaces. © 2011 Pleiades Publishing, Ltd.
Macias-Duarte A.,University of Sonora |
Panjabi A.O.,Rocky Mountain Bird Observatory
Auk | Year: 2013
Grassland bird populations have shown persistent declines over the past four decades in North America. Possible explanations for the declines include decreased winter survival because of habitat deterioration. To address this hypothesis, we evaluated the relationship between habitat structure and winter survival of Vesper Sparrows (Pooecetes gramineus) in Chihuahuan Desert grasslands of northern Mexico. We radiotagged and monitored the survival of 102 individuals during the winters of 2009 and 2010. We obtained visual estimates of vegetation structure and composition at every individual's radiotelemetry location. We used an exponential regression model to estimate daily survival rates and determine the association between habitat structure and survival. We estimated a daily winter survival probability of 99.1% (95% confidence interval: 97.4-99.7%) for Vesper Sparrows in both years. Our survival analysis suggests that habitat structure is an important predictor of winter survival. Average grass height and shrub height were positively related to Vesper Sparrow survival. Our results suggest that grassland bird populations may be negatively affected by poor grassland conditions during the winter and that low winter survival may be an important factor in population declines. Winter habitat conditions in the Chihuahuan Desert grasslands are shaped primarily by grazing and climate, highlighting the need to improve range management, especially in Mexico, as a means to reverse persistent population declines of grassland birds. Copyright © 2013 by The American Ornithologists' Union.
Sotelo-Cruz N.,University of Sonora
Gaceta Medica de Mexico | Year: 2012
The Stevens-Johnson syndrome (SJS) and the toxic epidermal necrolysis (TEN) are clinical conditions manifesting as adverse cutaneous reaction to drugs in majority of cases, constituting the same clinical spectrum, differing only in the severity of epidermolysis; both conditions are distinguished by their severity and extensiveness of skin lesions; it can also involve mucous membranes of eyes, respiratory, digestive and urogenital tracts. Two per 1,000,000 are affected annually, among them approximately 20% are children and both of them are considered as potentially fatal medical emergency conditions. Even though the condition was described 89 years ago, until now the exact pathophysiology has not been completely explained. An immune-mediated mechanism has been implicated in its origin, which involves cytotoxic lymphocytes, cytokines, Fas-ligand in keratinocyte apoptosis; genetic makers also has been identified in some racial groups (HLA-B*1520, HLA-B*5801) in relationship with specific susceptibility to certain drugs such as carbamazepine, allopurinol. In children there are no uniform criteria for classification of the skin lesions, neither for the treatment, however recently the authors describe better response of the patients with use intravenous immunoglobulin (IGIV).
Olmos D.,University of Sonora
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2010
In this paper, the Fitzhugh-Nagumo (FHN) equations and a modified FHN (MFHN) are considered. For the modified version, the recovery variable v has three different time scales. By considering different parameters in the local dynamics of the MFHN equations, it is observed that the phenomenon of reflection and annihilation at an impermeable boundary is observed just as in the Beeler-Reuter model. The interaction of spirals obtained with the FHN, MFHN, and Beeler-Reuter model, and an obstacle is also considered. The phenomenon of reflection of the spiral wave at a boundary changes when the boundary becomes an obstacle. Four properties for attachment of a spiral wave to an obstacle are presented in this work. © 2010 The American Physical Society.
Corral Verdugo V.,University of Sonora
Environment, Development and Sustainability | Year: 2012
As in most areas of psychology, a negative bias permeates the study of the subject of Conservation Psychology: sustainable behavior (SB). SB constitutes the set of actions aimed at protecting the socio-physical environment. This behavior is sometimes addressed as having negative antecedent-instigators (fear, guilt, shame), activated to avoid undesirable outcomes from environmental degradation. Also, psycho-environmental researchers often visualize negative psychological consequences (discomfort, inconvenience, sacrifice) of SB. Yet, a number of studies reveal that positive psychological antecedents (capacities, emotions, virtues and strengths) as well as positive psychological consequences (satisfaction, psychological well-being, and happiness) of SB are also significant determinants of pro-environmental actions. In this paper, I argue that SB is positive behavior originated by positive dispositional factors, and maintained by psychological benefits. By combining the emergent fields of positive psychology and the psychology of sustainability, an alternative approach for the study of the positive psychology of sustainable behavior is outlined. © 2012 Springer Science+Business Media B.V.