Aspectos citológicos da diferenciação de tecidos de cafeeiro cultivado "in vitro"

Callus was established from leaves and shoots of Coffea arabica L. on nutrient medium with various levels of auxins and kinetin. Morphogenesis is controllable in such callus tissues by manipulation of the growth factor levels in the media. The study shows that callus culture obtained from leaves are in different states of differentiation, i.e., although the calluses were similar in appearence, their morphogenetical potential was different. The cells in culture show a great range of growth and form, and that form and behaviour of such cells do not correspond with recognized cell types in normal plant tissues or meristems. Proembryoids and vascularization (Fig. 1), giant cells (Fig. 4) and other patterns of cell differentiation (Figs. 2 and 3) were observed. The initiation of an organized system is probably dependent upon some rather specific environmental conditions. The extent to which certain specific types of differentiation are concomitant would seem to be a reflection of the extent to which common factors are involved. Thus, in this type of change, casuality of the nuclear change to the other changes would be unlikely.O cultivo de explantes de folha de cafeeiro enriquecidos com hormônios mostrou que a partir de tecidos diferenciados ocorre uma desdiferenciação. Essa desdiferenciação alcança diferentes níveis devido, provavelmente, a fatores ambientais, e não genéticos. Observou-se nos calos obtidos uma variação nos padrões de diferenciação celular. Pro-embrióides e vascularização (Fig. 1), células gigantes (Fig. 4) e outros padrões de diferenciação (Figs. 2 e 3) foram observados. As células em cultura diferenciaram-se sem perder as potencialidades genéticas iniciais do embrião, do qual derivaram; mudanças ambientais e nos mecanismos de regulação gênica são responsáveis pela variação fenotípica observada. Explantes de caules de café produziram calos que diferenciaram-se em raiz e em parte aérea (Fig. 6) chegando-se a obter uma diferenciação até 3 pares de folhas. Discutem-se neste trabalho, vários aspectos relacionados com morfogênese e interações gênico-ambientais

Efeitos do beneficiamento na qualidade de sementes de milho infectadas por Fusarium moniliforme sheld

In order to evaluate processing effects on the quality of corn seeds infected by Fusarium moniliforme Sheld seeds were submitted to screen classification yielding 4 fractions (24/64; 22/64; 20/64; 18/64 of the inch) and the other part was separated by weight in a gravity separator. The separator originated three fractions that in turn were individually submitted to the same equipment generating, each one, three other fractions. All fractions were evaluated for germination, vigor, density, weight of a thousand seeds, and sanity. The width classification is not effective in the selection of infected seeds; however, the increase of seed width is followed by higher germination and vigor values.Com o objetivo de avaliar os efeitos do beneficiamento na qualidade de lotes com sementes de milho infectadas com Fusarium moniliforme Sheld, sementes foram submetidas à classificação por peneiras, originando 4 frações (24/64; 22/64; 20/64; 18/64 de polegada) e à separação por peso através da ação da mesa gravitational, originando três frações que foram individualmente submetidas ao mesmo equipamento gerando, cada uma, mais três frações. Todas as frações foram avaliadas quanto à germinação, ao vigor, à densidade, ao peso de mil sementes e à sanidade. A classificação por largura não é eficaz para separar as sementes infectadas; no entanto, o aumento da largura das sementes é acompanhado pela elevação dos valores da germinação e do vigor

Quasi Free 238U (e,e'f)-Cross Section in Macroscopic-Microscopic Approach

We present the result of a theoretical study of inclusive quasi free electrofission of $^{238}$U. The off-shell $$cross sections for the quasi free reaction stage have been calculated within the Plane Wave Impulse Approximation (PWIA), using a Macroscopic -Microscopic description of the proton and neutron single particle momentum distributions. Electron wave function distortion corrections were included using the effective momentum approximation, and the Final State Interaction (FSI) effects were calculated using an optical potential. The fissility for the proton single hole excited states of the residual nucleus $^{237}$Pa was calculated both without and with contributions of the pre-equilibrium emission of the particles. The fissility for $^{237,238}U$ residual nuclei was calculated within the compound nucleus model. The $(e,e^{\prime}f)-$cross sections thus obtained were compared with available experimental data.Comment: 26 pages, 7 figure

The MIDAS telescope for microwave detection of ultra-high energy cosmic rays

We present the design, implementation and data taking performance of the MIcrowave Detection of Air Showers (MIDAS) experiment, a large field of view imaging telescope designed to detect microwave radiation from extensive air showers induced by ultra-high energy cosmic rays. This novel technique may bring a tenfold increase in detector duty cycle when compared to the standard fluorescence technique based on detection of ultraviolet photons. The MIDAS telescope consists of a 4.5 m diameter dish with a 53-pixel receiver camera, instrumented with feed horns operating in the commercial extended C-Band (3.4 -- 4.2 GHz). A self-trigger capability is implemented in the digital electronics. The main objectives of this first prototype of the MIDAS telescope - to validate the telescope design, and to demonstrate a large detector duty cycle - were successfully accomplished in a dedicated data taking run at the University of Chicago campus prior to installation at the Pierre Auger Observatory.Comment: 13 pages, 18 figure

Soft tissue response to mandibular advancement using 3D CBCT scanning

This prospective longitudinal study assessed the 3D soft tissue changes following mandibular advancement surgery. Cranial base registration was performed for superimposition of virtual models built from cone beam computed tomography (CBCT) volumes. Displacements at the soft and hard tissue chin (n=20), lower incisors and lower lip (n=21) were computed for presurgery to splint removal (4–6 week surgical outcome), presurgery to 1 year postsurgery (1-year surgical outcome), and splint removal to 1 year postsurgery (postsurgical adaptation). Qualitative evaluations of color maps illustrated the surgical changes and postsurgical adaptations, but only the lower lip showed statistically significant postsurgical adaptations. Soft and hard tissue chin changes were significantly correlated for each of the intervals evaluated: presurgery to splint removal (r=0.92), presurgery to 1 year postsurgery (r=0.86), and splint removal to 1 year postsurgery (r=0.77). A statistically significant correlation between lower incisor and lower lip was found only between presurgery and 1 year postsurgery (r=0.55). At 1 year after surgery, 31% of the lower lip changes were explained by changes in the lower incisor position while 73% of the soft tissue chin changes were explained by the hard chin. This study suggests that 3D soft tissue response to mandibular advancement surgery is markedly variable

Energy and Flux Measurements of Ultra-High Energy Cosmic Rays Observed During the First ANITA Flight

The first flight of the Antarctic Impulsive Transient Antenna (ANITA) experiment recorded 16 radio signals that were emitted by cosmic-ray induced air showers. For 14 of these events, this radiation was reflected from the ice. The dominant contribution to the radiation from the deflection of positrons and electrons in the geomagnetic field, which is beamed in the direction of motion of the air shower. This radiation is reflected from the ice and subsequently detected by the ANITA experiment at a flight altitude of 36km. In this paper, we estimate the energy of the 14 individual events and find that the mean energy of the cosmic-ray sample is 2.9 EeV. By simulating the ANITA flight, we calculate its exposure for ultra-high energy cosmic rays. We estimate for the first time the cosmic-ray flux derived only from radio observations. In addition, we find that the Monte Carlo simulation of the ANITA data set is in agreement with the total number of observed events and with the properties of those events.Comment: Added more explanation of the experimental setup and textual improvement