1,316 research outputs found

    Alternate islands of multiple isochronous chains in wave-particle interactions

    Full text link
    We analyze the dynamics of a relativistic particle moving in a uniform magnetic field and perturbed by a standing electrostatic wave. We show that a pulsed wave produces an infinite number of perturbative terms with the same winding number, which may generate islands in the same region of phase space. As a consequence, the number of isochronous island chains varies as a function of the wave parameters. We observe that in all the resonances, the number of chains is related to the amplitude of the various resonant terms. We determine analytically the position of the periodic points and the number of island chains as a function of the wave number and wave period. Such information is very important when one is concerned with regular particle acceleration, since it is necessary to adjust the initial conditions of the particle to obtain the maximum acceleration.Comment: Submitte

    THE EFFECTS OF WATER RIGHTS AND IRRIGATION TECHNOLOGY ON STREAMFLOW AUGMENTATION COST IN THE SNAKE RIVER BASIN

    Get PDF
    Three species of salmon in the Snake River Basin have been listed as endangered. Recovery efforts for these fish include attempts to obtain increased quantities of water during smolt migration periods to improve habitat in the lower basin. Agriculture is the dominant user of surface flows in this region. This study investigates farmer cost of a contingent water contract requiring the agricultural release of stored irrigation supplies in low flow years during critical flow periods. Results show that contingent contracts can provide substantial quantities of water at a relatively modest cost without significantly affecting the agricultural base of the area.Resource /Energy Economics and Policy,

    17beta-estradiol promotes the synthesis and the secretion of annexin I in the CCRF-CEM human cell line.

    Get PDF
    AIMS: Annexin I (ANXA1), a 37kDa member of the annexin family of Ca2+-binding and phospholipid-binding proteins, is particularly abundant in various populations of peripheral blood leukocytes. Since this protein modulates the anti-inflammatory actions of the steroid hormones, the purpose of this study was to investigate the effects of the female sex steroid hormone, 17beta-estradiol (E2beta), on the synthesis and secretion of ANXA1 in the human CCRF-CEM acute lymphoblastic leukemia cell line. METHODS: Complementary reverse transcription-polymerase chain reaction and Western blot assays were performed to study the effect of E2beta on the expression of mRNA and protein ANXA1, respectively. RESULTS AND DISCUSSION: Treatment of CCRF-CEM cells with E2beta, for 30 min, stimulated the synthesis of ANXA1 mRNA molecules, and increased the cellular level of ANXA1 protein. Moreover, when the cells were incubated with E2beta under the same experimental conditions, a significant increase in the amount of ANXA1 secreted from the cells was also detected. ICI 182,780, a selective inhibitor of the intracellular estrogen receptor, had no effect on the E2beta-stimulated expression and externalisation of ANXA1. Taken together, these results indicate that E2beta induces de novo synthesis of ANXA1 and stimulates its secretion in the CCRF-CEM cell line, apparently through a mechanism independent of the intracellular estrogen receptor

    Isochronous island bifurcations driven by resonant magnetic perturbations in Tokamaks

    Full text link
    Recent evidences show that heteroclinic bifurcations in magnetic islands may be caused by the amplitude variation of resonant magnetic perturbations in tokamaks. To investigate the onset of these bifurcations, we consider a large aspect ratio tokamak with an ergodic limiter composed of two pairs of rings that create external primary perturbations with two sets of wave numbers. An individual pair produces hyperbolic and elliptic periodic points, and its associated islands, that are consistent with the Poincar\'e-Birkhoff fixed point theorem. However, for two pairs producing external perturbations resonant on the same rational surface, we show that different configurations of isochronous island chains may appear on phase space according to the amplitude of the electric currents in each pair of the ergodic limiter. When one of the electric currents increases, isochronous bifurcations take place and new islands are created with the same winding number as the preceding islands. We present examples of bifurcation sequences displaying (a) direct transitions from the island chain configuration generated by one of the pairs to the configuration produced by the other pair, and (b) transitions with intermediate configurations produced by the limiter pairs coupling. Furthermore, we identify shearless bifurcations inside some isochronous islands, originating nonmonotonic local winding number profiles with associated shearless invariant curves

    Morfometría de la apertura piriforme y morfología de los huesos nasales en la población brasileña por la radiografía postero-anterior de Caldwell

    Get PDF
    CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOPiriform aperture and nasal bone contribute to the formation of the nose. Its morphology varies according to ethnic group and gender. The piriform apertures and nasal bones of 97 individuals were examined radiographically through Caldwell radiographic technique and the types of nasal bones were classified according to Hwang et al. (2005). The width, height and area of piriform aperture were measured to demonstrate the difference according to gender. Statistical analysis was performed from the Student t test and analysis of variance (ANOVA). The most frequent type of nasal bone was A, and D was the most uncommon in both genders. In the Student t test significant differences between genders, height, width and area of the piriform aperture were obtained and were larger in males when compared to females. The dimensions of the piriform aperture were higher in males when compared to females, and therefore may be used as parameter for the distinction of gender in Brazilian population. The type A of nasal bone was the most frequent in the Brazilian population, contributing to ethnic differentiation in human identification292393398CAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL E NÍVEL SUPERIORCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOsem informaçãosem informaçãoLa apertura piriforme y el hueso nasal contribuyen a la formación de la nariz. Su morfología varía de acuerdo a los grupos étnicos y al sexo. Este estudio evaluó la morfología de la apertura piriforme y el hueso nasal y su relación con el sexo. Las aperturas piriformes y los huesos nasales de 97 personas fueron examinados radiográficamente mediante la técnica radiográfica de Caldwell, y los tipos de huesos nasales se clasificaron de acuerdo con Hwang et al. (2005). Se midió el ancho, la altura y el área de la apertura piriforme para demostrar las diferencias por sexo. El análisis estadístico se realizó a partir de la prueba t de Student y análisis de varianza (ANOVA). El tipo más frecuente de hueso nasal fue la A, y la D fue la menos común, en ambos sexos. En la prueba t de Student se obtuvo diferencias significativas entre los sexos, altura, ancho y área de la apertura piriforme, las que fueron mayores en hombres en comparación a las mujeres. Las dimensiones de la apertura piriforme fueron mayores en los hombres que en las mujeres, por lo que se puede utilizar como parámetro para la distinción de sexo en la población brasileña. En la población brasileña el tipo A de hueso nasal fue el más frecuente, lo que contribuye para la diferenciación étnica en la identificación human
    corecore