Silício No Desenvolvimento In Vitro Da Orquídea Cattleya Forbesii

Addition of Silicon (Si) to culture media has been shown to improve the development of seedlings grown in vitro, and to reduce losses during the acclimatization phase. The objective of this study was to evaluate the in vitro growth of Cattleya forbesii (Orchidaceae) in MS medium containing five different concentrations of SiO2 (0.0, 0.5, 1.0, 1.5, and 2.0 g·L−1). At day 200, the following variables were measured: number of roots, average length of the root system, leaf area, number of leaves and shoots, shoot height, fresh and dry masses of roots and shoots, water content of roots and shoots, and pH of the culture medium. Most variables decreased as the concentration of Si increased, reducing the in vitro vegetative growth of C. forbesii. Accumulation of Si in leaf tissues was detected by scanning electron microscopy, confirming uptake by plants. The Si source and concentrations tested showed no beneficial effect on in vitro growth of C. forbesii. © 2016, Universidade Federal Rural do Semi-Arid. All rights reserved.291182

Modulational Instability Of Random Phase Plasmons In Collisional Plasmas

The modulational instability of random phase Langmuir waves in an unmagnetized collisional plasma is investigated. The growth rate of the instability is presented in several interesting limiting cases. The relevance of this investigation to space and laboratory plasmas is pointed out. © 1998 American Institute of Physics.5828462848Vedenov, A.A., Rudakov, L.I., (1965) Sov. Phys. Dokl., 9, p. 1073Vedenov, A.A., Gordeev, A.V., Rudakov, L.I., (1967) Plasma Phys., 9, p. 719Kadomtsev, B.B., (1965) Plasma Turbulence, , Academic, New YorkZakharov, V.E., (1972) Sov. Phys. JETP, 35, p. 908Stenflo, L., (1985) J. Geophys. Res., 90, p. 5355Shukla, P.K., Pant, H.C., Jain, V.K., (1990) Plasma Phys. Controlled Fusion, 32, p. 1349Vladimirov, S.V., Popel, S.I., Tsytovich, V.N., (1993) Phys. Fluids B, 5, p. 4109Braginskii, S.I., (1965) Reviews of Plasma Physics, p. 205. , edited by M. A. Leontovich Consultants Bureau, New YorkDrake, J.F., Sparks, L., Van Hoven, G., (1988) Phys. Fluids, 31, p. 81

Linear And Nonlinear Dispersive Alfvén Waves In Two-ion Plasmas

A set of coupled nonlinear equations for dispersive Alfvén waves (DAWs) in nonuniform magnetoplasmas with two-ion species is derived by employing a multifluid model. The DAW frequency is assumed to lie between the gyrofrequencies of the light and heavy ion impurities. In the linear limit, a local dispersion relation (LDR) is derived and analyzed. The LDR admits a new type of DAW in two-ion plasmas. Furthermore, it is found that stationary solutions of the nonlinear mode coupling equations in two-ion plasmas can be represented in the form of different types of coherent vortex structures. The relevance of our investigation to space and laboratory plasmas is pointed out. © 1998 American Institute of Physics.5829472951Hasegawa, A., Uberoi, C., (1982) The Alfvén Wave, , National Technical Information Service, Springfield, VAPetviashvili, V.I., Pokhotelov, O.A., (1992) Solitary Waves in Plasmas and in the Atmosphere, , Gordon and Breach, Reading, Berkshire, UKMikhailovskii, A.B., (1992) Electromagnetic Instabilities in An Lnhomogeneous Plasma, , Hilger, Institute of Physics, Bristol, UKMikhailovskii, A.B., Lakhin, V.P., Aburdzhaniya, G.D., Mikahailovskaya, L.A., Onishenko, O.G., Smolyakov, A.I., (1984) Plasma Phys. Controlled Fusion, 29, p. 1Liu, J., Horton, W., (1986) J. Plasma Phys., 36, p. 1Yu, M.Y., Shukla, P.K., Stenflo, L., (1986) Astrophys. J., 309, pp. L63Chmyrev, V.M., Pokhotelov, O.A., Marchenko, V.A., Lazarev, V.I., Streltsov, A.V., Stenflo, L., (1988) Phys. Scr., 38, p. 841Shukla, P.K., Birk, G.T., Dreher, J., Stenflo, L., (1996) Plasma Phys. Rep., 22, p. 818Peterson, W.K., Yau, M.W., Whalen, B.A., (1993) J. Geophys. Res., 98, p. 11177Maslennikov, D.I., Mikhailenko, V.S., Stepanov, K.N., (1997) Fizika Plazmy, 23, p. 1088(1997) Plasma Phys. Rep., 23, p. 1007Elifomov, A.G., Galvao, R.M.O., Nascimento, I.C., Amarante-Segundo, G., (1997) Plasma Phys. Controlled Fusion, 39, p. 1151Shukla, P.K., Birk, G.T., Bingham, R., (1995) Geophys. Res. Lett., 22, p. 671Meiss, J.D., Horton, W., (1983) Phys. Fluids, 26, p. 990Stenflo, L., (1987) Phys. Fluids, 30, p. 3297Stenflo, L., (1994) Phys. Lett. A, 186, p. 133Stenflo, L., (1996) Phys. Lett. A, 222, p. 378Camevale, C.F., Vallis, G.K., (1990) J. Fluid Mech., 213, p. 549Dauxois, T., (1994) Phys. Fluids, 6, p. 162

The pattern of growth hormone secretion during the menstrual cycle in normal and depressed women

Objective Major depression is associated to altered hypothalamic pituitary function. Stress is linked to elevated cortisol as well as menstrual cycle disturbance; however, there is no known relationship between depression and menstrual cycle disruption. The aim of this study was to investigate changes of growth hormone (GH) secretion during the menstrual cycle in normal and depressed women. Design Case-control study. Patients and methods Nineteen women affected with depression and 24 normal controls were included. The two groups had comparable body mass index (BMI), and age (29·4 ±9·8 vs. 28·6 ± 9·7 years). Nine depressed and 10 controls were studied in the follicular phase, while 10 depressed and 14 controls were studied in the luteal phase of the cycle. GH was sampled every 10 min for 24 h, and the data were analysed by the cluster pulse detection method. Results There was no difference in 24-h mean GH concentrations between depressed and control subjects (P =0·93), even after accounting for menstrual cycle phase (P = 0·38). GH pulse frequency was higher during the follicular phase of the cycle (P =0·032), and nocturnal GH was higher in the follicular phase of the cycle (P =0·05, and after adjusting for 24-h GH, P= 0·0138) regardless of whether thesubjects were depressed or healthy. Conclusions In studies of GH secretion in women with or without depression, it is necessary to control for the phase of menstrual cycle.NIMH MH 50030 NICHD K12HD01438Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49486/2/KasaVubuYoung.pd