Evidence for a synergistic interaction between isoprenaline and timolol on intraocular pressure in conscious rabbits

1. Interaction between topical isoprenaline and timolol on intraocular pressure was studied in conscious rabbits through changes of the dose-response curves. 2. Both drugs caused a dose-dependent fall of intraocular pressure mainly by reducing the aqueous humour formation. 3. When combined, timolol increased the response to submaximal concentrations of isoprenaline as well as EC50 (from 2.06 x 10(-3) M to 3.63 x 10(-3) M) and slope (from 1.21 to 1.89), but peak response to isoprenaline remained unchanged. 4. Discordance between experimental and theoretical additive curves as well as an interaction index smaller than 1 show that the interaction between both drugs is synergistic.     

User simulation in a stochastic dialog system

We present a new methodology of user simulation applied to the evaluation and refinement of stochastic dialog systems. Common weaknesses of these systems are the scarceness of the training corpus and the cost of an evaluation made by real users. We have considered the user simulation technique as an alternative way of testing and improving our dialog system. We have developed a new dialog manager that plays the role of the user. This user dialog manager incorporates several knowledge sources, combining statistical and heuristic information in order to define its dialog strategy. Once the user simulator is integrated into the dialog system, it is possible to enhance the dialog models by an automatic strategy learning. We have performed an extensive evaluation, achieving a slight but clear improvement of the dialog system.     

Processing of graded anode-supported micro-tubular SOFCs based on samaria-doped ceria via gel-casting and spray-coating

A simple gel-casting method was successfully combined with the spray-coating technique to manufacture graded anode-supported micro-tubular solid oxide fuel cells (MT-SOFCs) based on samaria-doped ceria (SDC) as an electrolyte. Micro-tubular anodes were shaped by a gel-casting method based on a new and simple forming technique that operates as a syringe. The aqueous slurry formulation of the NiO–SDC substrate using agarose as a gelling agent, and the effect of spray-coating parameters used to deposit the anode functional layers (AFLs) and electrolyte were investigated. Furthermore, pre-sintering temperature of anode substrates was systematically studied to avoid the anode–electrolyte delamination and obtain a dense electrolyte without cracks, after co-sintering process at 1450 °C. Despite the high shrinkage of substrate (～70%), an anode porosity of ～37% was achieved. MT-SOFCs with ～2.5 mm of outer diameter, 370 μm thick substrate, 20 μm thick AFLs and 15 μm thick electrolyte were successfully obtained. The use of AFLs with 30:70 and 50:50 wt% NiO–SDC allowed to obtain a continuous gradation of composition and porosity in the anode–electrolyte interface.     

Performance and stability of La0.5Sr0.5CoO3−δ perovskite as catalyst precursor for syngas production by partial oxidation of methane

The aim of this work was to investigate the performance and stability of the perovskite La_0.5Sr_0.5CoO_3−δ, as a potential catalyst precursor, for the synthesis gas production by partial oxidation of methane. For this purpose, the catalytic activity of La_0.5Sr_0.5CoO_3−δ was studied as a function of the temperature, flow rate and feed composition. In addition, its stability with the time-on-stream and redox cycles was also explored. Before and after testing, the catalyst precursor was characterized by X-ray diffraction, SEM-EDX and specific surface area (BET). The results evidenced a remarkable catalytic activity due to the stability of the cobalt, which is in a highly disperse state, in its reduced state. The CH₄ conversion and the CO and H₂ selectivities were enhanced with the increase of redox cycles. Finally, the precursor was totally regenerated to the initial perovskite structure under a specific thermal treatment.     

Electrical and mechanical characterization by instrumented indentation technique of La0.85Sr0.15Ga0.8Mg0.2O3−δ electrolyte for SOFCs

La_0.85Sr_0.15Ga_0.8Mg_0.2O_3?δ pellets obtained by the polymeric organic complex solution method, isostatic pressing and sintering at 1350 °C have been electrical and mechanically studied. Electrical measurements evidenced reasonable ionic conductivities (0.01 S cm^?1 at 800 °C), which were comparable to those reported for the La_1?xSr_xGa_1?yMg_yO_3?δ prepared by other synthesis methods. On the other hand, the mechanical properties (elastic modulus, E and hardness, H) have been determined at micro/nanometric scale using the instrumented indentation technique. While E did not vary significantly with the increasing indentation depth (h), H values strongly decreased with the indentation depth up to 500 nm. For h > 500 nm, both mechanical properties remained almost constant, thus obtaining E = 271 ± 6 GPa and H = 13.2 ± 0.4 GPa. Finally, the residual imprints and fracture mechanisms have been observed by atomic force microscopy (AFM).     

Mechanical Characterization of Copper-Copper Wires Joined by Friction Welding Using Instrumented Indentation Technique

Friction welding samples of both the fire-refined high-conductivity (FRHC) and electrolytically tough pitch (ETP) copper alloy wires have been mechanically characterized by instrumented indentation technique and tensile test. Hardness profiles in the perpendicular direction to the weld interface, in both the central and peripheral zones, of the as-welded FRHC-FRHC and ETP-ETP samples have been investigated at nano-/micrometric scale. The microstructures of welds have been observed using both the optical microscopy and scanning electronic microscopy. The results show the typical friction welding zones: the interface zone, the thermo-mechanically affected zone (TMAZ), and the transition zone between the TMAZ and the base metal zone (BMZ) that present a microstructure and hardness close to the base metal. No presence of a heat-affected zone is observed. Although both welds show the same tendency in hardness distribution, FHRC-FHRC weld presents a TMAZ narrower than ETP-ETP one, which produces a stronger drop in hardness with increasing of the distance from welding central line, and a higher difference in hardness between the central and peripheral zones. The tensile tests of ETP-ETP welds showed that all samples broke by the BMZ that is far away from the interface of the welded joint, while the most of the FRHC-FRHC welds are broken at the TMAZ region at low strengths. These appreciable differences in mechanical properties for the FHRC-FHRC welds are probably generated by a stronger variation in their microstructural properties. Therefore, it may justify the welding failures in the FHRC-FHRC weld at the typical tensile stress for an industrial cold-drawn process of wires.     

Characterization of fire-refined copper recycled from scrap

Certain properties of fire-refined copper recycled from scrap have been characterized. A method is presented to calculate the half-softening temperature and the annealing temperature that allows 30% elongation to failure, hereinafter referred to as _30% temperature, on the basis of hardness measurements. The relation between ultimate strain and ultimate elongation has been studied and is described by a mathematicale xpression that seems to be independent of copper composition and annealing temperature. The microstructure of annealed samples reveals that recrystallization begins at half-softening temperature, and is ending at _30% temperature, although grain growth is not observed. An optimal range of oxygen content has been found that gives the minimum _30% temperature for each studied composition, and a mathematical expression with which to calculate those minimum temperatures is developed. The influence of cold-working degree on _30% temperature is also described; these temperatures reach a constant minimum value for each composition at high deformation degrees of cold-working.     

Interannual vineyard crop variability in the Castilla–La Mancha region during the period 1991–1996 with Landsat Thematic Mapper images

The vineyard crop is considered an indicator of vegetation cover processes in the Castilla–La Mancha region, as the crop has undergone far-reaching changes in the last ten years: abandonment, removal of vineyards and replacement with other crops such as cereal. The so-called ‘Change detection’ is a process that allows identification of differences in the state of the vineyard by observing it at different times. Essentially, it involves the ability to quantify temporal effects using multi-temporal datasets.

The aim of this study is to analyse the vineyard variability during the period 1991–1996 using different Landsat-5 Thematic Mapper (TM) images belonging to an identified period that highlights differences in the vegetation phenology changes. The images were firstly georeferenced and radiometrically normalized for the change detection purpose. The study area is located in central Spain and involves five councils belonging to the Castilla–La Mancha region: Mota del Cuervo, Las Mesas, Tomelloso, Socuellamos and Villarrobledo, with a surface area of 174?040?ha. This area is especially cultivated by the vineyard crop. Moreover, the study area was classified with the images acquired in 1991, using the multi-temporal masking techniques for the vineyard inventory.

The changes experimented by the vineyard have been grouped in three categories: cereal (CE), abandoned vineyard (AB) and bare soil (BS). Therefore, two methods of Normalized Difference Vegetation Index (NDVI) image difference and NDVI Change Vector Analysis (CVA) were used to map these categories of change. The results indicate that 28.4% of vineyard area undergoes changes during the period 1991–1996. The results have been checked with the ground data and all information is highly conformed.     

Oxygenation kinetics of YBCO-TSMG samples using the nanoindentation technique

Since hardness is a quantitative measure of bulk mechanical properties, it can be used to examine the kinetics of crack propagation inside YBa₂Cu₃O_7−δ (YBCO or Y-123) ceramics. YBCO samples with a tetragonal phase were oxygenated at a range of temperatures (from 250 °C to 750 °C) for different times. For each oxygenation temperature and time, hardness was measured by the nanoindentation technique, to study the defects (macro-/microcracks and porosity) produced along the c-axis. These defects were visualized by optical microscopy. The main purpose of this study was to establish the oxygenation kinetics for YBCO samples, which were textured by the top-seeded melt growth technique. We studied the evolution of hardness perpendicular to the ab-plane, as measured by the nanoindentation technique at a maximum penetration depth of 150 nm. The results indicate that the nanoindentation technique can be used successfully to monitor oxygenation and to establish the kinetics of the process.     

AeDEn: An adaptive framework for dynamic distribution over mobile environments

Mobile computing is a domain in great expansion. Wireless networks (gsm, satellite, etc) and Portable Information Appliances pias (laptops, PDAs, cellular phones, etc) are developing very rapidly. More and more mobile users would like to execute their applications with the same quality of service as on their desktop station, whatever their needs in memory and computing power. Using such applications in a mobile environment raises new challenges. Some of these applications are extremely costly in system and network resources, whereas pias resources are poor and wireless networks offer a very variable quality of connection. In this paper we propose an adaptive and dynamic distribution of applications on the local environment to overcome the poorness of available resources on pias, and to reduce and regulate variability effects. Moreover, due to the variety of distribution policies, we propose a framework providing adaptive distribution policies.