Resumo O presente estudo avaliou as respostas hematológicas, antiparasitária e de crescimento de tambaqui (Colossoma macropomum) após alimentação com dietas suplementadas com microalgas Arthospira platensis e Chlorella vulgaris (0%; 10% A. platensis; 10% C. vulgaris; e 5% A. platensis+5% C. vulgaris). Exemplares de tambaqui (n=60, 62,57±8,76 g) foram alimentados por 20 dias com as dietas experimentais. Amostras de sangue foram coletadas para determinação dos parâmetros hematológicos e brânquias foram retiradas para contagem de parasitos monogenéticos. A suplementação com A. platensis 10% reduziu o RBC, consequentemente aumentando os valores de VCM e HCM. As contagens de leucócitos (total) e de monócitos, eosinófilos e basófilos reduziram com o uso de A. platensis. Números altos de monócitos, eosinófilos e basófilos em tambaqui alimentado com dietas com 10% C. vulgaris foram observados e podem ter ocorrido devido à presença de imunoestimulantes na composição da microalga utilizada. Redução dos níveis plasmáticos de colesterol total em tambaqui indicou que a inclusão das duas microalgas (A. platensis 5%+C. vulgaris 5%) pode indicar que maiores benefícios à saúde do peixe do que quando separadamente suplementada. Ambas mostraram eficácia contra parasitos monogenéticos das brânquias de tambaqui. Assim, conclui-se que o uso das microalgas C. vulgaris e A. platensis promovem ação imunoestimulante com eficácia antiparasitária em C. macropomum. hematológicas Colossoma macropomum 0% 0 (0% 10 C 5 platensis5 platensis+5 vulgaris. . vulgaris) n=60, n60 n 60 (n=60 6257876 62 57 8 76 62,57±8,7 g 2 experimentais RBC HCM (total monócitos utilizada (A 5C 5%+C suplementada Assim concluise conclui se (0 1 platensis+ n=60 n6 6 (n=6 625787 7 62,57±8, ( n=6 (n= 62578 62,57±8 n= (n 6257 62,57± 625 62,57 62,5 62,

Abstract The present study evaluated the hematological, antiparasitic and growth responses in tambaqui (Colossoma macropomum) fed with diets supplemented with the microalgae Arthrospira platensis and Chlorella vulgaris (0%; 10% A. platensis; 10% C. vulgaris; and 5% A. platensis+5% C. vulgaris). Tambaqui (n=60, 62.57 ± 8.76 g) were fed for 20 days with experimental diets. Blood samples collection was done to determine hematological parameters, and gills were removed to identify and count monogenetic parasites. Supplementation with A. platensis 10% reduced red blood cells count, in consequence mean corpuscular volume and mean hemoglobin concentration increased. Total leukocyte, monocyte, eosinophil, and basophil counts reduced with the use of A. platensis. Higher monocytes, eosinophil, and basophil numbers in tambaqui fed with diet supplemented with 10% C. vulgaris were observed and may have been due to the presence of immunostimulants in this microalga composition. Reduction on total cholesterol in tambaqui that received both microalgae (A. platensis 5%+C. vulgaris 5%) may indicate that combined supplementation presented greater benefits to the health for C. macropomum than separately. Both microalgae were efficient against monogenetic parasites of tambaqui. Thus, the dietary use of the microalgae A. platensis and C. vulgaris provided immunostimulant and antiparasitic efficacy in C. macropomum. Colossoma 0% 0 (0% 10 A C 5 platensis5 platensis+5 vulgaris. . vulgaris) n=60, n60 n 60 (n=60 6257 62 57 62.5 876 8 76 8.7 g 2 parameters increased leukocyte monocyte eosinophil monocytes composition (A 5C 5%+C separately Thus (0 1 platensis+ n=60 n6 6 (n=6 625 62. 87 7 8. ( n=6 (n= n= (n

Electric transport properties measured by Van der Pauw resistivity experiments of Low-Temperature Molecular Beam Epitaxy (LT-MBE) GaAs samples are used to identify a method to improve the resistivity of GaAs material. We present results on five samples grown at 265, 310, 315, 325, and 345 ºC. The electric measurements were carried out at temperatures ranging from 130 to 300 K. In this temperature range the dominant transport process is identified as variable range hopping. The hopping parameter plotted against the growth temperature is shown to present a maximum. The mechanisms responsible for this behavior are discussed in relation to the compensation ratio.

Coherent emission efficiency in a 100Å GaAs SQW microcavity was enhanced one order when pumped resonantly at 10 K, compared to the off-resonant excitation. The usual kink observed in the exciton emission linewidth as well as in the emission intensity in relation to the pump power, changes smoothly instead of the usual abrupt kink observed in the off-resonant microcavity laser. In addition, polarization measurements show a correlation relationship between the pump light polarization and the cavity emission polarization.

In this work several structural and chemical properties of self-assembled InAs islands grown on GaAs(001) are studied using surface x-ray scattering with synchrotron radiation. The technique of x-ray diffraction under grazing incidence condition was employed to differentiate coherent and incoherent islands. We used a model of a strained pyramidal island to interpret the x-ray results and correlate size and strain-state of these islands. The degree of GaAs interdiffusion in the islands was inferred from the variation of volume of the unit cell. The Poisson's ratio of the two materials involved establishes a limit of tetragonal distortion for this material. Any variation in this distortion is associated with the presence of Ga inside the islands.

We have observed Low Frequency Oscillations (LFO) in a GaAs sample grown by molecular beam epitaxy (MBE) at 300 °C as a function of applied electric field, temperature and illumination intensity. Time series of the oscillations for different values of the applied electric field at room temperature were obtained. We have also obtained the jxE characteristics as a function of temperature and light intensity. We were able to control the LFO using three experimental parameters, the electrical field, which controls the oscillation frequency, and the temperature and illumination intensity, which control the carrier density and field-enhanced trapping. We were able to identify the LFO dependence on the carrier density and on the field-enhanced trapping.