Supersensitivity induced by the toxin of Brazilian scorpion venom (Tityus serrulatus Lutz e Mello)

The purified toxin of the Brazilian scorpion venom (TsTX) enhances the pharmacological actions of directly and indirectly acting substances on several preparations. The enhancing action of TsTX is more pronounced for the indirectly acting drugs, which is highly suggestive of a prejunctional site of action. Secondarily, TsTX does also produce an unspecific increase of sensitivity at the level of the pharmacological receptor itself. The mechanism by which these changes are brought about remains to be determined.     

Vapor-liquid equilibrium in mixtures of 1,3 dioxolane-water

Vapor-liquid equilibrium measurements were carried out with a Stage-Müller apparatus on mixtures of 1,3 dioxolane-water at isobaric conditions. Thermodynamic consistency of data was checked, and liquid-phase activity coefficients were correlated using Wilson's equation, which was applied to various groups of data, each with a restricted range of temperature variation. The parameters δ_kj of Wilson's equation proved to be independent of the temperature.     

Analysis of Frequency Selective Surfaces at Millimeter Wave Band Using the Hertz Vector Potential Method

In this work, the Hertz vector potential method was used to obtain the dyadic Green’s function components for frequency selective surfaces (FSS) on an anisotropic layer. The considered structures are composed by periodic arrays of conducting crossed dipole and rectangular patch elements. Results of reflected power were obtained by using the moment method. Curves for the reflected power versus frequency are presented as function of the structural parameters, assuming x, y, and z orientation for the optical axis in the anisotropic substrate.     

Remote atmospheric breakdown for standoff detection by using an intense short laser pulse

A remote atmospheric breakdown is a very rich source of UV and broadband visible light that could provide an early warning of the presence of chemical-biological warfare agents at extended standoff distances. A negatively chirped laser pulse propagating in air compresses in time and focuses transversely, which results in a rapid laser intensity increase and ionization near the focal region that can be located kilometers away from the laser system. Proof-of-principle laboratory experiments are performed on the generation of remote atmospheric breakdown and the spectroscopic detection of mock biological warfare agents. We have generated third harmonics at 267 nm and UV broadband radiation in air from the compression and focusing of femtosecond laser pulses. Fluorescence emission from albumin aerosols as they were illuminated by the femtosecond laser pulse has been observed.     

Efficiency optimization for a diode-pumped Nd:YAG ceramic slab laser

With the help of photometric calculations based on ray-tracing algorithms, we have optimized the efficiency of the optical pumping of a Nd:YAG ceramic slab laser. The slab pumping is performed by means of two horizontal diode laser array stacks. The use of two small reflecting walls allows the sort of duct coupling that is capable of significantly improving the performance of the system. Our first experiments with a simple direct coupling provided a maximum extraction of slightly more than 160 W at a 20% slope efficiency level. The use of the optimized short duct coupling leads us to the extraction of 350 W with a slope efficiency of 51%, making use of the same diode arrays. The laser design is suitable for the construction of cw sources with a power output above 1 kW.     

Determination of (111) ordered domains on platinum electrodes by irreversible adsorption of bismuth

Irreversible adsorbed bismuth can be used to determine the fraction of (111) domains on a given platinum sample. On Pt(111) electrodes, the surface redox process of adsorbed bismuth takes place at 0.63 V in a well-defined peak. The behavior of this redox process on the Pt(111) vicinal surfaces indicates that the bismuth atoms involved in the redox process are only those deposited on the (111) terrace sites and that the charge under the peak at 0.63 V is directly proportional to the number of sites on (111) ordered domains (terraces). The good linear relationship obtained between the charge for the bismuth redox process and the number of (111) terrace sites on the vicinal surfaces allows construction of a calibration curve. This calibration curve has been used to directly estimate the amount of (111) ordered domain terrace sites on polycrystalline platinum samples with different surface ordered domains. The results agree with what we would expect from our knowledge of these surfaces.     

Methods for Operations Planning in Airport Decision Support Systems

Simulation and decision support tools can help airport ground controllers to improve surface operations and safety, leading to enhancements in the process of traffic flow management. In this paper, two planning approaches for automatically finding the best routes and sequences for demanded operations are proposed and analyzed. These approaches are integrated into a general decision support system architecture. The problem addressed is the global management of departure operations, moving aircraft along airport taxiways between gate positions and runways. Two global optimization approaches have been developed together with a suitable problem representation: a modified time-space flow algorithm and a genetic algorithm, both aimed at minimizing the total ground delay. The capability and performance of these planning techniques have been illustrated on simulated samples of ground operations at Madrid Barajas International Airport.This work was funded by CICYT (TIC2002-04491-C02-02) and CAM (07T/0034/2003 1)     

Gamma dose from activation of internal shields in IRIS reactor

The International Reactor Innovative and Secure is a modular pressurised water reactor with an integral design. This means that all the primary system components, such as the steam generators, pumps, pressuriser and control rod drive mechanisms, are located inside the reactor vessel, which requires a large diameter. For the sake of better reliability and safety, it is desirable to achieve the reduction of vessel embrittlement as well as the lowering of the dose beyond the vessel. The former can be easily accomplished by the presence of a wide downcomer, filled with water, which surrounds the core region, while the latter needs the presence of additional internal shields. An optimal shielding configuration is under investigation, for reducing the ex-vessel dose due to activated internals and for limiting the amount of the biological shielding. MCNP 4C calculations were performed to evaluate the neutron and the gamma dose during operation and the 60Co activation of various shields configurations. The gamma dose beyond the vessel from activation of its structural components was estimated in a shutdown condition, with the Monte Carlo code FLUKA 2002 and the MicroShield software. The results of the two codes are in agreement and show that the dose is sufficiently low, even without an additional shield.     

Adaptive Resource Sharing Strategies for UMTS Multiservice Mobiles

In this paper, a multiservice transmission scheme which joints voice, video, interactive game and signaling is evaluated for the dedicated channel of the Universal Mobile Telecommunications System. The transmission rate for each service is determined by means of an adaptive transport format selection. In the UMTS standard, this selection is based on power allocation provided by radio resource controller, trying to match the Eb/No requirements of the individual services. An appropriate selection of the individual rates of each multiplexed service, taking into account its particular QoS requirements, will provide a more efficient resource management than the transmission only restricted to power allocation. For this purpose, we propose and evaluate a new selection strategy based on buffer occupation, delay requirements and target bit rate keeping power constraints that intends to improve the basic operation trying to minimize the impact of the whole network. Video and game services are multiplexed in upper layers (logical channels) sharing a common transmission rate (transport channel). In this paper, it is proposed a new strategy to share the transmission rate set for this transport channel between both services taking into account their particular requirements. Results show that considering delay constraints provides a more balanced performance of the multiplexed services.