RESUMEN
Particle-type solutions are observed in out-of-equilibrium systems. These states can be motionless, oscillatory, or propagative depending on the injection and dissipation of energy. We investigate a family of localized standing waves based on a liquid-crystal light valve with spatiotemporal modulated optical feedback. These states are nonlinear waves in which energy concentrates in a localized and oscillatory manner. The organization of the family of solutions is characterized as a function of the applied voltage. Close to the reorientation transition, an amplitude equation allows us to elucidate the origin of these localized states and establish their bifurcation diagram. Theoretical findings are in qualitative agreement with experimental observations. Our results open the possibility of manipulating localized states induced by light, which can be used to expand and improve the storage and manipulation of information.
RESUMEN
Homogeneously driven dynamical systems exhibit multistability. Depending on the initial conditions, fronts present a rich dynamical behavior between equilibria. Qualitatively, this phenomenology is persistent under spatially modulated forcing. However, the understanding of equilibria and front dynamics organization is not fully established. Here, we investigate these phenomena in the high-wavenumber limit. Based on a model that describes the reorientation transition of a liquid crystal light valve with spatially modulated optical forcing and the homogenization method, equilibria and fronts as a function of forcing parameters are studied. The forcing induces patterns coexisting with the uniform state in regions where the system without forcing is monostable. The front dynamics is characterized theoretically and numerically. Experimental results verify these phenomena and the law describing bistability, showing quite good agreement.
RESUMEN
Mujer de 54 años con antecedentes de Hipertensión arterial e Hipotiroidismo. Historia de aproximadamente 3 meses de evolución caracterizado al inicio por ánimo bajo, cambios en el comportamiento con aparición progresiva de conductas extraña, ideas delirantes y alucinaciones visuales y auditivas, junto con disminución en requerimientos de hormonas tiroídeas hasta la suspensión. Consulta en varios centros donde se cataloga como Trastorno depresivo severo con síntomas psicóticos, Síndrome confusional, Síndrome Psicótico. En este contexto se pesquisa Hipertiroidismo con títulos elevados de Anticuerpos Antitiroídeos e inicia tratamiento con Metimazol y Betabloqueo. Tras extenso estudio que descartan causas infecciosas, neoplásicas y autoinmunes; se inicia tratamiento con pulsos de Metilprednisolona con excelente y rápida respuesta clínica, la cual mantiene durante el curso del seguimiento con dosis decrecientes de corticoides.
A 54-year-old woman with a history of arterial hypertension and hypothyroidism. History of approximately 3 months of evolution characterized at the beginning by low mood, changes in behavior with progressive appearance of bizarre behaviors, delusional ideas and visual and auditory hallucinations. Consultation in several centers where it is classified as severe Depressive disorder with psychotic symptoms, Confusional syndrome, Psychotic syndrome. Hyperthyroidism is investigated with high titers of Antithyroid Antibodies and initiates treatment with Methimazole and Betablock. After extensive study that ruled out infectious, neoplastic and autoimmune causes; Treatment with Methylprednisolone pulses is initiated with excellent and rapid clinical response, which is maintained during the course of follow-up with decreasing doses of corticosteroid.
Asunto(s)
Humanos , Femenino , Persona de Mediana Edad , Tiroiditis Autoinmune/complicaciones , Tiroiditis Autoinmune/tratamiento farmacológico , Encefalopatías/etiología , Tiroiditis Autoinmune/diagnóstico , Metilprednisolona/uso terapéutico , Metimazol/uso terapéutico , Anticuerpos/análisisRESUMEN
Estudio de 20 familias de pacientes demenciados que fueron hospitalizados en el Servicio de Psiquiatria del Hospital Universitario "Luis Razetti" en el lapso 1982-1986; estudiándose los aspectos psicológicos del grupo familiar por su relación con el enfermo demenciado haciendo énfasis en la persona encargada del paciente. La relación desencadena problemas de coexistencia que alteran los sentimientos hacia el enfermo, la tolerancia de la vida en el ambiente familiar y hasta la salud mental de algunos de los miembros de la familia, llegando incluso a retirar el enfermo del grupo familiar