2,299 research outputs found
First Record Of Passiflora Pedata L. (passifloraceae) From Maranhão State, Northeastern Brazil
This study reports the first record of Passiflora pedata L. (Passifloraceae) from the state of Maranhão and from the Northeast Region of Brazil. The species was collected in the municipality of Buriticupu, which is located in a remnant of Amazon Forest in western Maranhão. This work adds to the knowledge of the flora of Maranhão and the distribution of P. pedata in the Brazilian Amazon. © 2016 Check List and Authors.12
Efficient Quantum Computation using Coherent States
Universal quantum computation using optical coherent states is studied. A
teleportation scheme for a coherent-state qubit is developed and applied to
gate operations. This scheme is shown to be robust to detection inefficiency.Comment: 6 pages, 5 figures, extended and modified (in print, PRA
The Giant Anisotropic Magnetocaloric Effect In Dyal2
We report on calculations of the anisotropic magnetocaloric effect in DyAl2 using a model Hamiltonian including crystalline electrical field effects. The anisotropic effect is produced by the rotation of a constant magnetic field from the easy to a hard magnetic direction in the crystal and is enhanced by the first order nature of the field induced spin reorientation transition. The calculated results indicate that for a field with modulus of 2 T rotating from a hard to the easy direction, the isothermal magnetic entropy (Δ Siso) and adiabatic temperature (Δ Tad) changes present peak values higher than 60% the ones observed in the usual process, in which the field direction is kept constant and the modulus of the field is varied. © 2008 American Institute of Physics.1049Tishin, A.M., Spichkin, Y.I., (2003) The Magnetocaloric Effect and Its Applications, , 1st ed. (Institute of Physics, Bristol)Warburg, E., (1881) Ann. Phys. (N.Y.), 13, p. 141. , 0003-4916Brown, G.V., (1976) J. Appl. Phys., 47, p. 3673. , 0021-8979 10.1063/1.323176Pecharsky, V.K., Gschneidner Jr., K.A., (1997) Phys. Rev. Lett., 78, p. 4494. , 0031-9007 10.1103/PhysRevLett.78.4494Von Ranke, P.J., De Oliveira, N.A., Mello, C., Garcia, D.C., De Souza, V.A., Magnus, A., Carvalho, G., (2006) Phys. Rev. B, 74, p. 054425. , 0163-1829 10.1103/PhysRevB.74.054425Hill, T.W., Wallace, W.E., Craig, R.S., Inuone, T.J., (1973) Solid State Chem., 8, p. 364. , 10.1016/S0022-4596(73)80036-2De Oliveira, I.G., Garcia, D.C., Von Ranke, P.J., (2007) J. Appl. Phys., 102, p. 073907. , 0021-8979 10.1063/1.2783781Lima, A.L., Tsokol, A.O., Gschneidner Jr., K.A., Pecharky, V.K., Lograsso, T.A., Schlagel, D.L., (2005) Phys. Rev. B, 72, p. 024403. , 0163-1829 10.1103/PhysRevB.72.024403Von Ranke, P.J., De Oliveira, I.G., Guimarães, A.P., Da Silva, X.A., (2000) Phys. Rev. B, 61, p. 447. , 0163-1829 10.1103/PhysRevB.61.447Von Ranke, P.J., De Oliveira, N.A., Garcia, D.C., De Sousa, V.S.R., De Souza, V.A., Magnus, A., Carvalho, G., Reis, M.S., (2007) Phys. Rev. B, 75, p. 184420. , 0163-1829 10.1103/PhysRevB.75.184420Purwins, H.G., Leson, A., (1990) Adv. Phys., 39, p. 309. , 0001-8732 10.1080/00018739000101511Von Ranke, P.J., Pecharsky, V.K., Gschneidner Jr., K.A., (1998) Phys. Rev. B, 58, p. 1211
Optimizing the fast Rydberg quantum gate
The fast phase gate scheme, in which the qubits are atoms confined in sites
of an optical lattice, and gate operations are mediated by excitation of
Rydberg states, was proposed by Jaksch et al. Phys. Rev. Lett. 85, 2208 (2000).
A potential source of decoherence in this system derives from motional heating,
which occurs if the ground and Rydberg states of the atom move in different
optical lattice potentials. We propose to minimize this effect by choosing the
lattice photon frequency \omega so that the ground and Rydberg states have the
same frequency-dependent polarizability \alpha(omega). The results are
presented for the case of Rb.Comment: 5 pages, submitted to PR
Elastase-2, a tissue alternative pathway for angiotensin II generation, plays a role in circulatory sympathovagal balance in mice
In vitro and ex vivo experiments indicate that elastase-2 (ELA-2), a chymotrypsin-serine protease elastase family member 2A, is an alternative pathway for angiotensin II (Ang II) generation. However, the role played by ELA-2 in vivo is unclear. We examined ELA-2 knockout (ELA-2KO) mice compared to wild-type (WT) mice and determined whether ELA-2 played a role in hemodynamics [arterial pressure (AP) and heart rate (HR)], cardiocirculatory sympathovagal balance and baroreflex sensitivity. The variability of systolic arterial pressure (SAP) and pulse interval (PI) for evaluating autonomic modulation was examined for time and frequency domains (spectral analysis), whereas a symbolic analysis was also used to evaluate PI variability. In addition, baroreflex sensitivity was examined using the sequence method. Cardiac function was evaluated echocardiographically under anesthesia. The AP was normal whereas the HR was reduced in ELA-2KO mice (425 ± 17 vs. 512 ± 13 bpm from WT). SAP variability and baroreflex sensitivity were similar in both strains. The LF power from the PI spectrum (33.6 ± 5 vs. 51.8 ± 4.8 nu from WT) and the LF/HF ratio (0.60 ± 0.1 vs. 1.45 ± 0.3 from WT) were reduced, whereas the HF power was increased (66.4 ± 5 vs. 48.2 ± 4.8 nu from WT) in ELA-2KO mice, indicating a shift toward parasympathetic modulation of HR. Echocardiographic examination showed normal fractional shortening and an ejection fraction in ELA-2KO mice; however, the cardiac output, stroke volume, and ventricular size were reduced. These findings provide the first evidence that ELA-2 acts on the sympathovagal balance of the heart, as expressed by the reduced sympathetic modulation of HR in ELA-2KO mice
On Aharonov-Casher bound states
In this work bound states for the Aharonov-Casher problem are considered.
According to Hagen's work on the exact equivalence between spin-1/2
Aharonov-Bohm and Aharonov-Casher effects, is known that the
term cannot be neglected in the
Hamiltonian if the spin of particle is considered. This term leads to the
existence of a singular potential at the origin. By modeling the problem by
boundary conditions at the origin which arises by the self-adjoint extension of
the Hamiltonian, we derive for the first time an expression for the bound state
energy of the Aharonov-Casher problem. As an application, we consider the
Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the
expression for the harmonic oscillator energies and compare it with the
expression obtained in the case without singularity. At the end, an approach
for determination of the self-adjoint extension parameter is given. In our
approach, the parameter is obtained essentially in terms of physics of the
problem.Comment: 11 pages, matches published versio
Produtividade e vigor do maracujazeiro-amarelo plantado em covas e plantio direto sob manejo orgânico.
O objetivo deste trabalho foi avaliar o vigor e a produtividade do maracujazeiro-amarelo plantado em diferentes tamanhos de cova e plantio direto sob manejo orgânico. O experimento foi conduzido de 2005 a 2007, no Setor de Agricultura Ecológica da Universidade Federal do Acre, em delineamento de blocos casualizados, constituÃdos de cinco tratamentos, quatro repetições e quatro plantas por parcela. Foram avaliados cinco tipos de preparo do solo: T1 cova do tamanho do torrão (0,19 x 0,063m) com adubação em cobertura; T2 cova de 0,30 x 0,30 x 0,30m com adubação de plantio na cova; T3 cova de 0,30 x 0,30 x 0,30m com adubação de plantio em cobertura; T4 cova de 0,50 x 0,50 x 0,50m com adubação de plantio na cova; e T5 cova de 0,50 x 0,50 x 0,50m com adubação de plantio em cobertura. O tamanho da cova e o plantio direto não influenciaram o vigor da planta e a biomassa de raÃzes. O número de frutos por planta e a produtividade, na segunda e na somatória das duas safras, foram maiores com plantio direto e com covas cúbicas de 0,30m. Após dois anos de cultivo, a densidade do solo foi maior na camada de 0-5cm de profundidade num raio de 20cm da planta para o plantio em covas de 0,50m com adubação na cova e menor para o plantio direto, não havendo diferença entre os demais tratamentos. O plantio direto ou o plantio em covas pequenas com dimensões de 0,30 x 0,30 x 0,30m proporcionou maior produtividade de maracujá que o plantio em covas maiores, mesmo não influenciando o vigor das plantas e a massa seca de raÃzes
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