La perla

Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-201

Microbial community dynamics in diesel waste biodegradation using sequencing batch bioreactor operation mode (SBR)

The dynamic of molecular microbial community during diesel waste biodegradation was investigated. The waste was treated in bioreactors operated in sequencing batch operation mode (SBR) in four cycles of 72 h, using optimized setpoints (pH, initial waste load, C:N ratio, aeration). Optimal conditions allowed the system to reach biodegradation of 53.3, 96.0, 76.2 and 75.0% at the end of cycles one, two three and four, respectively. Oxygen uptake rate (OUR) indicated increases in microbial activity from cycle one to cycle two (124.9 to 252.9 mgO2/L/h) and decreases in cycles three and four (120.4 to 108.8 mgO2/L/h, respectively). Investigations of microbial diversity showed changes in the microbial community members at the end of the cycle one. Significant reductions in the relative ecotoxicity were observed beginning with cycle two, and the reductions extended until the end of process. The SBR operation mode proved to be an efficient method for treating the diesel waste, and the process allowed for relevant reductions in the hydrocarbon content of the waste along with an increase in its environmental quality. Changes in the microbial members are evidence of the synergistic action of the microbiota in the process.Key words: Microbial diversity, denaturing gradient gel electrophoresis, sequencing batch, biodegradation

Morphometric characterization of fruits and seeds and the effect of the temperature on germination of Parkia pendula (Willd.) Benth. ex Walp

Parkia pendula (Willd.) Benth. ex Walp., \ue9 uma esp\ue9cie arb\uf3rea, caracter\uedstica dos est\ue1dios iniciais da sucess\ue3o, de ocorr\ueancia natural no Brasil. Pertence \ue0 fam\uedlia Fabaceae, com grande potencial na recupera\ue7\ue3o de \ue1reas degradadas. O presente trabalho foi conduzido no Centro de Ci\ueancias Agr\ue1rias da Universidade Federal de Alagoas, objetivando a caracteriza\ue7\ue3o morfom\ue9trica de frutos e sementes dessa esp\ue9cie, bem como identificar a melhor temperatura para uso em testes de germina\ue7\ue3o. O fruto \ue9 do tipo legume, deiscente, polisp\ue9rmico, contendo em m\ue9dia 16 sementes por unidade. Estas apresentam formato elipsoidal, embri\ue3o axial, com 10,1 mm de comprimento, 4,9 mm de largura por 3,1mm de espessura. As temperaturas de 25 e 30oC proporcionaram as maiores porcentagem e velocidade de germina\ue7\ue3o, enquanto que a temperatura de 15oC e acima de 35\ubaC influenciaram negativamente a germinabilidade das sementes.Parkia pendula (Willd.) Benth. ex Walp. is a tree species, characteristic of the initial phases of succession, of natural occurrence in Brazil. It belongs to the Mimosaceae family, with great potential in the recovery of degraded areas. The present work aims to characterize fruits and seeds morphometrically as well to identify the best temperature for use in germination test. The fruit is a type of legume, dehiscent, polispermic, with 16 seeds, approximately, per unit. The seeds present ellipsoidal format, axial embryo, with 10,1 mm of length, 4,9 mm of width and 3,1 mm of thickness. The temperatures of 25\ubaC and 30\ubaC provided them larger germinability, while the temperature of 15\ubaC and above 35\ubaC influenced these characteristics negatively

Limit on the Radiative Neutrinoless Double Electron Capture of 36^{36}Ar from GERDA Phase I

Neutrinoless double electron capture is a process that, if detected, would give evidence of lepton number violation and the Majorana nature of neutrinos. A search for neutrinoless double electron capture of $^{36}$Ar has been performed with germanium detectors installed in liquid argon using data from Phase I of the GERmanium Detector Array (GERDA) experiment at the Gran Sasso Laboratory of INFN, Italy. No signal was observed and an experimental lower limit on the half-life of the radiative neutrinoless double electron capture of $^{36}$Ar was established: $T_{1/2} >$ 3.6 $\times$ 10$^{21}$ yr at 90 % C.I.Comment: 7 pages, 3 figure