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A membrane model for cytosolic calcium oscillations. A study using Xenopus oocytes.

Jafri, M S; Vajda, S; Pasik, P; Gillo, B
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /07/1992 EN
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Cytosolic calcium oscillations occur in a wide variety of cells and are involved in different cellular functions. We describe these calcium oscillations by a mathematical model based on the putative electrophysiological properties of the endoplasmic reticulum (ER) membrane. The salient features of our membrane model are calcium-dependent calcium channels and calcium pumps in the ER membrane, constant entry of calcium into the cytosol, calcium dependent removal from the cytosol, and buffering by cytoplasmic calcium binding proteins. Numerical integration of the model allows us to study the fluctuations in the cytosolic calcium concentration, the ER membrane potential, and the concentration of free calcium binding sites on a calcium binding protein. The model demonstrates the physiological features necessary for calcium oscillations and suggests that the level of calcium flux into the cytosol controls the frequency and amplitude of oscillations. The model also suggests that the level of buffering affects the frequency and amplitude of the oscillations. The model is supported by experiments indirectly measuring cytosolic calcium by calcium-induced chloride currents in Xenopus oocytes as well as cytosolic calcium oscillations observed in other preparations.

Treinta ejercicios de memoria; A treinta años del golpe

Adamoli, María Celeste; Blejmar, Jordana; Longoni, Ana; Luzuriaga, Pablo; Meirás, José Luis; Trímboli, Javier
Fonte: Buenos Aires : Ministerio de Educación, Ciencia y Tecnología Publicador: Buenos Aires : Ministerio de Educación, Ciencia y Tecnología
Tipo: Livro
ES
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Los treinta años del golpe de Estado ocurrido el 24 de marzo de 1976 se presentaron como una oportunidad particularmente significativa para reflexionar sobre aquello que sucedió en el pasado reciente de nuestro país, interpelándonos acerca de qué futuro como sociedad queremos.; Este libro, impulsado con la intención de servir como disparador para trabajos sostenidos de reflexión, debate y producción entre docentes y estudiantes cuenta con la colaboración de escritores, poetas, educadores, psicoanalistas, periodistas, cineastas, artistas plásticos, fotógrafos y actores que eligieron la imagen que les resultó más representativa de su propia experiencia durante aquellos años para que a partir de esa imagen escribieran un texto breve explicando su elección y realizando lo que llamamos ejercicio personal de memoria.

A general fractional white noise theory and applications to finance

Elliott, R.; Van Der Hoek, J.
Fonte: Blackwell Publishers Publicador: Blackwell Publishers
Tipo: Artigo de Revista Científica
Publicado em //2003 EN
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We present a new framework for fractional Brownian motion in which processes with all indices can be considered under the same probability measure. Our results extend recent contributions by Hu, Øksendal, Duncan, Pasik-Duncan, and others. As an application we develop option pricing in a fractional Black-Scholes market with a noise process driven by a sum of fractional Brownian motions with various Hurst indices.; Robert J. Elliott, John Van Der Hoek; The definitive version is available at www.blackwell-synergy.com