In this contribution, we present the synchronization in dynamical complex networks with varying couplings. We identify two kinds of variations—(i) Non autonomous (Time-varying) couplings: where the coupling strength depends exclusively on time, (ii) Autonomous or Varying couplings (evolution) where the coupling strength depends on the behavior of the interconnected systems. The coupling strength in (i) is exogenous whereas in (ii) the coupling strength is endogenous and is defined by the states of the systems in the nodes. The exponential stability of the synchronization is ensured for the non autonomous couplings, due to the imposition of the coupling strength. Whereas, in the case of evolutionary couplings the exponential stability of the synchronization is not guaranteed for all time, due to the couplings are not controlled or imposed. We present an overview of these features in complex networks and illustrated by means of numerical examples.

El problema más limitante del cultivo de la papa en muchas regiones del mundo, lo constituye la gota o tizón tardío ocasionado por el hongo Phytophthora infestans. Esta investigación se realizó con el objetivo de determinar variaciones poblacionales de este patógeno, basadas en el tipo de apareamiento y en la presencia de razas fisiológicas en 19 aislamientos de P. infestans obtenidos en plantas de papa (Solanum tuberosum) variedades Diacol Capiro, ICA Puracé e ICA Cumanday; papa criolla (Solanum phureja), pepino (Solanum muricatum) y tomate (Lycopersicon esculentum) en diferentes zonas del Departamento de Antioquia (Colombia).Los resultados obtenidos a partir de un apareamiento patrón A1, con los aislamientos colectados en las diferentes zonas sugieren la existencia de una población de P. infestans con un solo tipo de apareamiento. La prueba de virulencia del hongo, realizada en folíolos de 11 diferenciales de papa mostró la presencia de 6 razas fisiológicas, de las cuales la más frecuente fue la 7446 (58%), con los factores de virulencia 1-2-3-4-7-10-11. Aislamientos monozoospóricos presentaron los mismos factores de virulencia que sus respectivos aislamientos recolectados en el campo, lo que sugiere homogeneidad de la población fungosa. La gran complejidad de las razas fisiológicas de P. infestans podría estar influenciada por diversos factores genéticos y medioambientales.Aceptado para publicación: mayo 1997.

This research provided the validation of a model of the influence of marketing learning intention, personal motivation and absorptive capacity of marketing knowledge on the acquisition of tacit marketing knowledge and this in turn on the transfer of tacit knowledge of marketing between the employees of small and medium size hotels in the city of Playa del Carmen, Quintana Roo, in Mexico. Through a quantitative and transversal investigation, 229 employees of the hotel sector were integrated. The results showed that personal motivation and the intention to learn marketing positively intervene in the acquisition of tacit knowledge of marketing and, influenced by the capacity of absorption of marketing knowledge, directly affect the transfer of tacit knowledge of marketing.

Introduction: Patients with rheumatoid arthritis (RA) are at increased risk of developing tuberculosis, and even more so if they receive biological agents. In Mexico, the prevalence of latent tuberculosis infection (LTBI) in RA diagnosed by interferon-gamma release assay (IGRA) is largely unknown. The objective was to determine LTBI prevalence and the associated risk factors in rheumatoid arthritis patients.Methods: A cross-sectional study was performed comprising 82 patients with RA who attended the rheumatology service at a second-level hospital. Demographic characteristics, comorbidity, Bacillus Calmette-Guerin (BCG) vaccination and smoking history, type of treatment, disease activity and functional capacity were investigated. The Disease Activity Score 28 and the Health Assessment Questionnaire-Disability Index were applied for the estimate of RA activity and functional capacity. Further information was compiled from the electronic medical records and personal interviews. LTBI was determined by QuantiFERON TB Gold Plus (QIAGEN, Germantown, USA).Results: Prevalence of LTBI was 14% (95% confidence interval (CI): 8.6% to 23.9%). Factors associated with LTBI were history of smoking (odds ratio (OR) = 6.63 95% CI 1.01 to 43.3) and disability score (OR = 7.19 95%CI 1.41 to 36.6).Conclusions: The prevalence of LTBI in Mexican patients with RA was 14%. Our results suggest prevention of smoking and functional incapacity could reduce the risk of LTBI. Further research could endorse our results.