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Pulsed laser deposition of ZnO thin films, using KrF laser, is analysed. The films were deposited on (001) sapphire substrates at 400 °C, at two different oxygen pressures (0·3 and 0·4 mbar) and two different target-substrate distances (30 and 40 mm). It is observed that in order to obtain good quality in the photoluminescence of the films, associated with oxygen stoichiometry, it is needed to maximize the time during which the plasma remains in contact with the growing film (plasma residence time), which is achieved by selecting suitable combinations of oxygen pressures and target to substrate distances. It is also discussed that for the growth parameters used, the higher probability for ZnO films growth results from the oxidation of Zn deposited on the substrate and such process takes place during the time that the plasma is in contact with the substrate. Moreover, it is observed that maximizing the plasma residence time over the growing film reduces the rate of material deposition, favouring the surface diffusion of adatoms, which favours both Zn-O reaction and grain growth. [ABSTRACT FROM AUTHOR]

Pulse laser ablation as a new method for thorn elimination is presented. The new technique can work thanks to the use of pulsed light which is absorbed in a selective way, specifically in the thorns. An optical characterization of both thorn and cactus leave after and before irradiation, permits to find most convenient laser parameters as wavelength, pulse length and energy. By laser photoacoustic technique it is possible to monitoring the process in real time, checking online the cleaning results. The feasibility of performing the selective laser ablation of thorns with advantages over traditional methods was proved. [ABSTRACT FROM AUTHOR]

Bat surveys are frequently undertaken using ultrasonic detectors to determine the species present in an area on the basis of the identity of echolocation calls. We compared three techniques for using the Anabat II detector: the detector pointed along tracks (flyways) versus the detector pointed across tracks (non-flyways); recording output to audio cassette (analogue) versus direct recording to computer (digital); and active hand-held recording versus static automatic recording. In addition, we derived a species-accumulation curve from all-night Anabat recordings in the wet–dry tropics of the Northern Territory. We found no significant difference between flyway and non-flyway recordings; significantly more calls were identified from digital recordings; and significantly more species were detected using hand-held than static recordings. Species-accumulation analysis suggests that the minimum time required to achieve a satisfactory (80%) inventory of bat species at a site is during the three-hour period immediately after sunset. We use our findings to make recommendations for the design of bat surveys using the Anabat II detector. [ABSTRACT FROM AUTHOR]

O propósito deste ensaio é mostrar que a versão de infinitismo epistemológico defendida por Peter Klein é uma forma de externalismo. São apresentados os problemas mais importantes que o infinitismo deve resolver e também a diferença fundamental entre internalismo e externalismo em epistemologia. Como conclusão, é apresentada uma indicação sobre a melhor maneira de entender o infinitismo e como superar os problemas que surgem da forma externalista de infinitismo defendida por Klein

O problema do conhecimento fácil tem sido definido na literatura epistemológica contemporânea com um problema que nasce de duas formas distintas. O propósito deste ensaio é mostrar que essas supostas maneiras diferentes de gerar o mesmo problema em verdade originam dois problemas distintos, que requerem respostas distintas. Um deles está relacionado à aquisição fácil (inaceitável) de conhecimento de primeira-ordem e o outro à aquisição fácil (inaceitável) de conhecimento de segunda-ordem. Além disso, é apresentada a maneira como o infinitismo, a teoria epistêmica segundo a qual as razões que justificam uma opinião devem ser infinitas em número e não-repetidas, pode lidar com cada um desses problemas

O problema do critério é um dos mais importantes da epistemologia. A resposta que se dá a ele definirá um aspecto fundamental das teorias do conhecimento. Neste ensaio, o problema do critério é apresentado e algumas das consequüências geradas pela aceitação de exigências metaepistemicas são analisadas. Em especial, essas consequências são avaliadas em relação ao infinitismo - a teoria epistemológica segundo a qual as razões que sustentam nossas crenças devem ser infinitas em número e não-repetidas. Ao final, sustenta-se que as cláusulas que exigem que a metajustificação seja necessária para o conhecimento não apenas tornam as teorias epistemológicas mais plausíveis, mas também que ausência de tais exigências acaba criando problemas muito difíceis, como o assim chamado chr(38)quot;problema do conhecimento fácilchr(38)quot;

Patients with hypereosinophilic syndrome (HES) display a very heterogeneous clinical picture ranging from asymptomatic cases to very aggressive forms. We report a 38-year-old woman with progressive HES who developed severe myelofibrosis and was treated by allogeneic stem cell transplantation, using peripheral blood (PBSCT) instead of bone marrow as the source of progenitor cells, after conditioning with cytoxan and busulphan. To the best of our knowledge, this is the first case of HES with myelofibrosis treated with PBSCT. The patient remains alive 8 months post-PBSCT, and bone marrow fibrosis has significantly decreased following transplantation. Bone Marrow Transplantation (2000) 25, 217–218. [ABSTRACT FROM AUTHOR]

The aim of this research is to identify the operational conditions and performance of low cost tubular digesters producing biogas from the slaughterhouse wastewater treatment. Three full scale sequenced tubular digesters (of more than 8 m 3 each), operating in a slaughterhouse in Cochabamba (Bolivia), have been monitored during one year. The Organic Load Rate (OLR) varied from 0.04 to 1.13 kgSV/m 3 d (0.04–1.07 kgCOD/m 3 d), and the Hydraulic Retention Time (HRT) from 3.2 to 87.4 days. The passive solar heating design considered drove the slurry temperature to 27 °C, 8 °C more than mean ambient temperature. The first digester has been filled with soda bottle plastic rings in order to increase the internal effective surface and evaluate, obtaining that an increment in 67% of the internal effective surface, more than doubles the biogas production and enables higher OLRs. A Biogas Production Rate (BPR) peak of 0.2 m 3 /m 3 d was observed for OLR = 0.37 kgSV/m 3 d, HRT = 9.7d and Specific Biogas Production (SBP) = 0.55 m 3 /kgSV. COD removal achieves values above 70% from HRT>19 d. A comparison with other anaerobic digestion technologies demonstrates that low cost tubular digesters with biofilm carriers, are competitive for OLR<0.5 kg COD/m 3 d of biogas production, and for 0.25 kgCOD/m 3 d, when the focus is on COD removal. [ABSTRACT FROM AUTHOR]