Global Alfven Wave Heating of the Magnetosphere of Young Stars

Excitation of a Global Alfven wave (GAW) is proposed as a viable mechanism to explain plasma heating in the magnetosphere of young stars. The wave and basic plasma parameters are compatible with the requirement that the dissipation length of GAWs be comparable to the distance between the shocked region at the star's surface and the truncation region in the accretion disk. A two-fluid magnetohydrodynamic plasma model is used in the analysis. A current carrying filament along magnetic field lines acts as a waveguide for the GAW. The current in the filament is driven by plasma waves along the magnetic field lines and/or by plasma crossing magnetic field lines in the truncated region of the disk of the accreting plasma. The conversion of a small fraction of the kinetic energy into GAW energy is sufficient to heat the plasma filament to observed temperatures.Comment: Submitted to ApJ, aheatf.tex, 2 figure

Validação de método para estudo de deposição de inseticidas biológicos em florestas.

Tem sido dada muito pouca atenção aos estudos da deposição de inseticidas biológicos, os quais tem sido aplicados com equipamento desenvolvido para uso com químicos. O objetivo desta pesquisa foi avaliar um método para a analise da deposição de agrotóxicos em florestas de eucaliptos, caracterizado pelo uso de uma calda de pulverização marcada com traçador e uma técnica especial de amostragem. Empregou-se o cobre como traçador, na forma de fungicida, cuja analise espectrofotométrica e de baixo custo, fácil de execução, alem de possibilitar um excelente nível de recuperação das plantas. Utilizaram-se cartões de papel mata-borrão como alvo artificial para amostrar as gotas. Cartões grampeados em barbantes, em distancias preestabelecidas, foram colocados sobre as plantas, possibilitando uma amostragem estratificada por alturas. Para o solo, os cartões foram colocados em discos de Petri e distribuídos sob a copa das arvores, entre plantas e entre as linhas de plantio. Os resultados indicam que 61% do produto aplicado ficaram retidos nas plantas, 31% atingiram o solo e 8% podem ter sido perdidos através da "exo-deriva".bitstream/item/143340/1/CNPMA-BOLET.-PESQ.-4-99.pd

Comparative electron temperature measurements of Thomson scattering and electron cyclotron emission diagnostics in TCABR plasmas

We present the first simultaneous measurements of the Thomson scattering and electron cyclotron emission radiometer diagnostics performed at TCABR tokamak with Alfven wave heating. The Thomson scattering diagnostic is an upgraded version of the one previously installed at the ISTTOK tokamak, while the electron cyclotron emission radiometer employs a heterodyne sweeping radiometer. For purely Ohmic discharges, the electron temperature measurements from both diagnostics are in good agreement. Additional Alfven wave heating does not affect the capability of the Thomson scattering diagnostic to measure the instantaneous electron temperature, whereas measurements from the electron cyclotron emission radiometer become underestimates of the actual temperature values. (C) 2010 American Institute of Physics. [doi:10.1063/1.3494379]811

Preliminary measurements on diel CH4 and N2O fluxes on Brachiaria pasture.

Brazil has extensive pasture areas for beef cattle grazing. An experiment was carried out in summer in a Brachiaria pasture in Southeastern Brazil, characterized by hot and humid climate in summer and dry in winter, with the objective of measuring hourly fluxes of methane and nitrous oxide from soil and identifying a possible relationship with environmental parameters, including air temperature, soil temperature, solar radiation, photosynthetically active radiation (PAR), and soil moisture. Temperature and radiation data were obtained from a climatological station on February 13 and 14, 2020, starting at 9:00 am and ending at the same hour of the next day. Soil moisture data were recorded by humidity sensors. The gas collection method used was the static closed chamber. Five chambers were used at the same time. Methane and nitrous oxide concentrations were sampled every 2 hours, in intervals of 0, 10, 20, 30, and 40 minutes. The gas samples were extracted by BD 60 mL syringes with a three-way luer lock valve and then transferred to 12 mL vacuum vials of the Labco Exetainer brand. A Thermo Scientific chromatograph model, Trace 1310, was used to determine the concentrations of gases. The statistical analysis was performed using the PROC CORR procedure of the SAS program. Preliminary results showed that N2O fluxes peaked at 3 p.m. with around 10 ?g N-N2O m-2 h-1 and a minimum value of -2 ?g N-N2O m-2 h-1 at 1 a.m. N2O fluxes were positively correlated with air temperature (0.70939 /0.0066) and with PAR (0.59037/0.0337), while they were negatively correlated with relative humidity (-.69266/0.0087). Methane correlated negatively with soil temperature (-0.88646/<0.001), although the concentrations were very low throughout the day. Other diel measurements are going to be carried out and the experiment will be repeated in the summer season

Wigner Functions and Separability for Finite Systems

A discussion of discrete Wigner functions in phase space related to mutually unbiased bases is presented. This approach requires mathematical assumptions which limits it to systems with density matrices defined on complex Hilbert spaces of dimension p^n where p is a prime number. With this limitation it is possible to define a phase space and Wigner functions in close analogy to the continuous case. That is, we use a phase space that is a direct sum of n two-dimensional vector spaces each containing p^2 points. This is in contrast to the more usual choice of a two-dimensional phase space containing p^(2n) points. A useful aspect of this approach is that we can relate complete separability of density matrices and their Wigner functions in a natural way. We discuss this in detail for bipartite systems and present the generalization to arbitrary numbers of subsystems when p is odd. Special attention is required for two qubits (p=2) and our technique fails to establish the separability property for more than two qubits.Comment: Some misprints have been corrected and a proof of the separability of the A matrices has been adde