Aproveitamento da casca de bacuri para elaboração de biscoitos.

Disponível também on-line. Publicado também no V Fórum de Pesquisa, Ensino, extensão e Pós-graduação da UEPA, 2008, Belém, PA. V FORPEEXP

Structure and Dynamics of the Globular Cluster Palomar 13

We present Keck/DEIMOS spectroscopy and Canada-France-Hawaii Telescope/MegaCam photometry for the Milky Way globular cluster Palomar 13. We triple the number of spectroscopically confirmed members, including many repeat velocity measurements. Palomar 13 is the only known globular cluster with possible evidence for dark matter, based on a Keck/High Resolution Echelle Spectrometer 21 star velocity dispersion of σ = 2.2 ± 0.4 km s^(–1). We reproduce this measurement, but demonstrate that it is inflated by unresolved binary stars. For our sample of 61 stars, the velocity dispersion is σ = 0.7^(+0.6)_(–0.5) km s^(–1). Combining our DEIMOS data with literature values, our final velocity dispersion is σ = 0.4^(+0.4)_( –0.3) km s^(–1). We determine a spectroscopic metallicity of [Fe/H] = –1.6 ± 0.1 dex, placing a 1σ upper limit of σ_([Fe/H]) ~ 0.2 dex on any internal metallicity spread. We determine Palomar 13's total luminosity to be M_V = –2.8 ± 0.4, making it among the least luminous known globular clusters. The photometric isophotes are regular out to the half-light radius and mildly irregular outside this radius. The outer surface brightness profile slope is shallower than typical globular clusters (Σ α r^η, η = –2.8 ± 0.3). Thus at large radius, tidal debris is likely affecting the appearance of Palomar 13. Combining our luminosity with the intrinsic velocity dispersion, we find a dynamical mass of M_(1/2) = 1.3^(+2:7)_(–1.3) × 10^3 M_☉ and a mass-to-light ratio of M/L_V = 2.4^(+5.0)_(–2.4) M_☉/L_☉. Within our measurement errors, the mass-to-light ratio agrees with the theoretical predictions for a single stellar population. We conclude that, while there is some evidence for tidal stripping at large radius, the dynamical mass of Palomar 13 is consistent with its stellar mass and neither significant dark matter, nor extreme tidal heating, is required to explain the cluster dynamics

Crescimento inicial de milho em solo adubado com diferentes compostos orgânicos.

Foram elaborados cinco compostos orgânicos com diferentes composições, todos a base de esterco caprino, bagaço de coco e capim elefante, enriquecidos com torta de mamona, fosfato natural de gafsa e sulfato de potássio, de modo que, a final, cada pilha tivesse concentrações diferenciadas de nutrientes. O experimento foi montado em vasos contendo solo e os compostos preparados, dispostos em delineamento experimental inteiramente casualisado,, com seis tratamentos, sendo uma testemunha, e quatro repetições. Aos 28 dias após o plantio foi efetuado o corte das plantas, avaliando-se o número de folhas, a altura das plantas, o diâmetro do colo e o peso de matéria seca. De um modo geral, os compostos promoveram maior crescimento das plantas de milho que a testemunha (sem composto) com destaque para o composto de número 22 (77% de bagaço de coco, 20% de esterco caprino e 3% de sulfato de potássio)

Aproveitamento da borra de açaí para produção de biscoitos.

Este trabalho avaliou a farinha da borra de açaí na substituição parcial da farinha de trigo na formulação de biscoito

Capacidade higroscópica de farinhas de diferentes frutas.

Publicado também no V Fórum de Pesquisa, Ensino, extensão e Pós-graduação da UEPA, 2008, Belém, PA. V FORPEEXP

Screening nuclear field fluctuations in quantum dots for indistinguishable photon generation

A semiconductor quantum dot can generate highly coherent and indistinguishable single photons. However, intrinsic semiconductor dephasing mechanisms can reduce the visibility of two-photon interference. For an electron in a quantum dot, a fundamental dephasing process is the hyperfine interaction with the nuclear spin bath. Here we directly probe the consequence of the fluctuating nuclear spins on the elastic and inelastic scattered photon spectra from a resident electron in a single dot. We find the nuclear spin fluctuations lead to detuned Raman scattered photons which are distinguishable from both the elastic and incoherent components of the resonance fluorescence. This significantly reduces two-photon interference visibility. However, we demonstrate successful screening of the nuclear spin noise which enables the generation of coherent single photons that exhibit high visibility two-photon interference.Comment: 5 pages, 4 figures + Supplementary Informatio