True airspeed measured by airborne laser Doppler velocimeter

Velocimeter utilizing carbon dioxide laser measures true airspeed of aircraft. Results of flight tests indicate that clear-weather airspeeds can be measured with accuracy better than 0.1% at altitudes up to 3000 meters; measurements can be made at much greater altitudes in cloudy or turbid air

The Effects of Music Genre on Cardiovascular Performance and Enjoyment in Young Adults

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The role of body rotation in bacterial flagellar bundling

In bacterial chemotaxis, E. coli cells drift up chemical gradients by a series of runs and tumbles. Runs are periods of directed swimming, and tumbles are abrupt changes in swimming direction. Near the beginning of each run, the rotating helical flagellar filaments which propel the cell form a bundle. Using resistive-force theory, we show that the counter-rotation of the cell body necessary for torque balance is sufficient to wrap the filaments into a bundle, even in the absence of the swirling flows produced by each individual filament

In vitro multiplication of Swietenia macrophylla King (Meliaceae) from juvenile shoots.

Big-leaf mahogany (Swietenia macrophylla King) is an important species for timber production that is considered the most valuable in the world. For this reason its exploitation is indiscriminate and leads this species to the risk of extinction. Moreover, mahogany is difficult to regenerate naturally and, when used in reforestation programs, plants are severely damaged by the shoot-borer (Hypsipyla grandella Zellar). This work aimed at developing the multiplication stage of micropropagation of Swietenia macrophylla King using juvenile material. After desinfestation, seeds were germinated in MS solid culture medium. Shoot formation from seeds occurred during five months, giving 5.54 nodal segments per seed. These explants were excised, each containing one axillary bud, and transferred on multiplication media. Four experiments with cytokinins were conducted, using media supplemented with 6-benzylaminopurine (BAP) (2.5 to 50.0 ?M), 2- isopentenyladenine (2-iP) (0; 1.1 to 8.8 ?M), combinations of BAP (0; 2.5 to 50.0 ?M) and 2-iP (2.2 ?M). For the first treatments the basal culture medium was MS medium and in the last one MS and QL media were used in separate experiments. When BAP was tested alone, the maximum point of multiplication rate average was obtained on medium containing 23.61 ?M, while 2-iP did not induce bud multiplication. On QL culture medium supplemented with the combinations of BAP (0; 2.5; 5.0; 10.0 e 20.0 ?M ) and 2-iP (2.2 ?M), there was no multiplication. The maximum point of multiplication rate average was 5.7 ?M, obtained when the MS culture medium was supplemented with 18.51 ?M BAP and 2.2 ?M 2-iP

High-performance operation of single-mode terahertz quantum cascade lasers with metallic gratings

A periodic array of thin slits opened on a metallic surface can act as a one-dimensional photonic crystal for the propagation of surface-plasmon waves. We have used such structure for the implementation of distributed feedback resonators in quantum cascade lasers emitting near 2.5 THz. Single-mode emission, stable at all injection currents and operating temperatures, was achieved both in pulsed and continuous wave. The devices exhibited output powers of several milliwatts with low threshold current densities of ∼100 A cm2

SISDIF - Sistema Computacional para Simulação de Dinâmica de Floresta Natural por meio do Processo de Difusão.

Este trabalho teve o objetivo de apresentar um sistema computacional desenvolvido em linguagem de programação Visual Basic 6 para simulação da dinâmica florestal em povoamentos naturais empregando o processo de difusão na prognose e projeção da floresta

The s-process branching at 185W

The neutron capture cross section of the unstable nucleus 185W has been derived from experimental photoactivation data of the inverse reaction 186W(gamma,n)185W. The new result of sigma = (687 +- 110) mbarn confirms the theoretically predicted neutron capture cross section of 185W of sigma = 700 mbarn at kT = 30 keV. A neutron density in the classical s-process of n_n = (3.8 +0.9 -0.8} * 1e8 cm-3 is derived from the new data for the 185W branching. In a stellar s-process model one finds a significant overproduction of the residual s-only nucleus 186Os.Comment: ApJ, in pres

SISDIF - Sistema Computacional para Simulação de Dinâmica de Floresta Natural por meio do Processo de Difusão.

Este trabalho teve o objetivo de apresentar um sistema computacional desenvolvido em linguagem de programação Visual Basic 6 para simulação da dinâmica florestal em povoamentos naturais empregando o processo de difusão na prognose e projeção da floresta