User-generated contents and reasoning-based personalization: Ingredients for a novel model of mobile TV

During the last years, we have witnessed the boom of the digital market due to the proliferation of emergent audiovisual services and the increasing number of broadband networks. In this scenario, users insistently demand innovative services for exchanging and sharing their own audiovisual contents. In order to meet these needs, in this paper we propose a system that broadcasts user-generated audiovisual contents for handheld devices in a mobile network based on the DVB-H broadcasting standard. Besides, our system offers diverse added-value services to these new active users, such as: (i) multi modal access (via Web or by client applications running locally in handheld devices) to digital contents, (ii) exploitation of return channels to transmit interactive contents that enhance the user’s experience, and (iii) annotation, sharing and personalized distribution of audiovisual contents. To achieve these goals, our system adopts well-known technologies for broadcasting and semantic annotation of audiovisual contents, as well as emergent technology from the so-called Web 2.0. A prototype of our system has been experimentally evaluated with a group of students from the University of Vigo, who were enthusiastic about the personalization capabilities offered by our TV system for a mobile setting.     

Atmospheric DMSO degradation in the gas phase: Cl-DMSO reaction. Temperature dependence and products

The reactions of Cl atoms and ClO radicals with CH3-SOCH3 (DMSO) have been studied using the discharge flow method with direct detection of DMSO, CO, and products by mass spectrometry. The absolute rate constant at room temperature measured for reaction 1, (CH3)2SO + Cl --> products, was k(1) = (1.7 +/- 0.3) x 10(-11) cm3 molecule(-1) s(-1). For reaction 2, (CH3)2SO + ClO --> products, only an upper limit could be established, k(2) < or = 6 x 10(-14) cm3 molecule(-1) s(-1) Reaction 1 has been found to proceed through adduct formation and further decomposition involving the cleavage of the C-S bound. The pressure effect on the Cl-DMSO reaction from 0.5 to 3 Torr was negligible, and the temperature dependence in the range 273-335 K was also very slight. The results obtained are related to previous studies of sulfur compounds, and the atmospheric implications are also discussed in relation to the homogeneous sinks of DMSO. Tropospheric lifetimes of DMSO based on average Cl and ClO concentrations and the measured rate constants have been calculated showing that the contribution of reaction 1 must be of minor relevance in the marine boundary layer. Reaction 2 is so slow that it does not play any role within the atmospheric sulfur chemistry.     

MHP‐OSGi convergence: a new model for open residential gateways

Nowadays, we are living in a time of important technological changes that affect our lives at home and our communication with the outside world. Among them, the developments in Interactive Digital TV (IDTV) and the smart home field can be considered as particularly important. Related to the former, the new Set‐Top Boxes (STBs) are not only a decoder for digital television broadcast but also an entry point to the Information Society and a suitable platform to support the execution of interactive applications. With regards to the latter, the Residential Gateways (RGs) combine different network technologies to allow the connection of different electronics devices and appliances at home, not only with each other but also with the Internet. Since there is no widespread consensus about the configurations and functions of the RGs, we propose to coordinate the two aforementioned worlds by extending the functionality of STBs to become a RG. Our proposal consists of merging the Multimedia Home Platform (MHP), one of the main standard frameworks for IDTV, with Open Service Gateway Initiative (OSGi), the most widely used open platform to set up RGs. To overcome the radically different nature of these specifications—the function‐oriented MHP middleware and the service‐oriented OSGi framework—we define a new kind of application, coined as XbundLET. This application is able to bridge the gap between the two frameworks and make their interaction feasible. We also show how this proposal has the potential to enable the production of scenarios that cannot currently be put into practice in a natural way. Copyright © 2006 John Wiley & Sons, Ltd.     

Determination of linear alkylbenzenesulfonates and their degradation products in soils by liquid chromatography-electrospray-ion trap multiple-stage mass spectrometry

Linear alkylbenzenesulfonates (LAS) (C(10)-C(13)) and their degradation products, sulfophenyl carboxylate compounds (SPCs) (C(2)-C(6), C(8), C(11)), have been extracted from soil samples with methanol, isolated, concentrated by solid-phase extraction, and determined by liquid chromatography/negative ion electrospray quadrupole ion-trap tandem mass spectrometry (MS(n)). The ion fragmentation processes and pathways were studied in detail by MS, MS(2), and MS(3). Upon collision-induced dissociation, the deprotonated molecules of LASs render the ethylene-substituted benzenesulfonate ion (m/z 183), the fragmentation of which gave the intense signal at m/z 119, corresponding to the ethylene-substituted phenoxide ion formed by the loss of sulfur dioxide. The fragmentation pattern of SPCs shows that, for the analytes of large carbon atom chains (>5C), the neutral loss of water is favored whereas for those of short carbon atoms chain, the loss of carbon dioxide is more frequent. Multiple reaction monitoring using isolation only for MS and using isolation and fragmentation for MS(2) and MS(3) were used to identify and quantify each compound. The three MS modes have been validated in terms of sensitivity, selectivity, and precision, showing that each MS stage used reduces sensitivity 10 times. Recoveries from soil were higher than 65% at LOQ level for all the analytes tested, except for C(2)-C(4) SPCs by any MS mode, with relative standard deviation lower than 19%. The utility of the method is demonstrated by successfully quantifying real samples treated with these products. Quantification limits for the methodology developed in this work ranged from 0.5 to 50 microg kg(-1) by MS, from 2 to 400 microg kg(-1) by MS(2), and from 20 to 4000 microg kg(-1) by MS(3). Concentration levels of LASs and SPCs-ranging from 0.1 to 15 mg kg(-1)-were found in soil samples amended with sludges, thus indicating their input and persistence in the soil compartment.     

Solid-phase microextraction liquid chromatography/tandem mass spectrometry to determine postharvest fungicides in fruits

A method to determine five postharvest fungicides (dichloran, flutriafol, o-phenylphenol, prochloraz, tolclofos methyl) in fruits (cherries, lemons, oranges, peaches) has been developed using solid-phase microextraction (SPME) coupled to liquid chromatography (LC) with photodiode array (DAD), mass spectrometry (MS), or tandem mass spectrometry (MS/MS) with ion trap detection. Extraction involved sample homogenization with an acetone/water solution (5:1), filtration, and acetone evaporation prior to fiber extraction. The pesticides were isolated with a fused-silica fiber coated with 50-microm Carbowax/template resin. The effects of pH, ion strength, sample volume, and extraction time were investigated, and their impact on the SPME-LC/MS was studied. Dynamic and static modes of desorption were compared and the variables affecting desorption processes in SPME-LC optimized. Static desorption provided the best recoveries and peak shapes. Recoveries at the limit of quantification (LOQ) levels were between 10% for prochloraz and 60% for o-phenylphenol, with relative standard deviations from 13.6% for prochloraz to 3.1% for o-phenylphenol. The versatility of the method was also exhibited by its excellent linearity in the concentration intervals between 0.0005 and 5 mg kg(-1) for dichloran and 0.01-10 mg kg(-1) for tolclofos methyl and prochloraz. LOQs ranged from 0.25 to 1 microg g(-1) using DAD, from 0.002 to 0.01 microg g(-1) using LC/MS, and from 0.0005 to 0.01 to microg g(-1) using LC/MS/MS. LOQs obtained in the present study using LC/MS and LC/MS/MS are lower than maximum residue limits established for all the fungicides in any matrix studied. The method enables to determine polar pesticides at low-microgram per gram levels in fruits.     

Adaptive control for the discrete-time parametric-strict-feedback form

The design of a state feedback controller for a class of SISO non-linear discrete-time systems is proposed. Namely, an alternative adaptive scheme is stated for the parametric-strict-feedback form. The control objective is to achieve tracking of a reference signal. Backstepping control is combined with a parameter estimator based on an orthogonalization process which overcomes the drawback of over-parameterization. Without assuming any growth conditions on the non-linearities, global boundedness and convergence are obtained in the closed loop system.     

Climatology of precipitation and lightning over the Pacific coast of southern Mexico retrieved from Tropical Rainfall Measuring Mission satellite products and World Wide Lightning Location Network data

Tropical Rainfall Measuring Mission (TRMM) satellite products for the period 1998–2009 are used to elaborate the climatology of vertical hydrometeor profiles and diurnal evolution of rainfall over the Pacific coast of southern Mexico. Precipitation characteristics are compared with those of lightning strokes, registered by the World Wide Lightning Location Network (WWLLN). The WWLLN data are verified against a climatological product (High-Resolution Monthly Climatology, HRMC) obtained from merged data sets of the TRMM Lightning Imaging Sensor (LIS) and the Optical Transient Detector (OTD) of the MicroLab-1 satellite. The TRMM 2A12 data set reveals that summer precipitation over the study region is a result of mixed phase processes, whereas during winter and spring, there is a significant contribution of warm precipitation over land. Diurnal evolution of rainfall retrieved from the 3B42 TRMM product and lightning registered by the WWLLN follows the sea–land breeze cycle measured by Baumgardner et al. (2006 Baumgardner, D., Raga, G.B., Grutter, M. and Lammel, G. 2006. Evolution of anthropogenic aerosols in the coastal town of Salina Cruz, Mexico: part I particle dynamics and land–sea interactions. Science of the Total Environment, 367: 288–301.  [Google Scholar]; Evolution of anthropogenic aerosols in the coastal town of Salina Cruz, Mexico: part I particle dynamics and land–sea interactions, Science of the Total Environment, 367, pp. 288–301). The spatial distribution of lightning is similar to that of rainfall; however, over the seaside coastal region, a phase shift is observed between these two variables, with the maximum lightning activity occurring about 3 hours before the precipitation peak. Monthly distribution of flashes is monomodal over land and bimodal over the ocean. Over the ocean, the evolution of monthly rainfall during summer is contrary to that of lightning activity: the months with highest precipitation (June and September) correspond to those with the lowest number of lightning strokes, whereas during the mid-summer drought, an increase in electrical activity is observed. An explanation for this phenomenon, related to the wind circulation and its effect on the concentration of aerosol particles, is proposed.     

Water and phosphoric acid uptake of poly [2,5-benzimidazole] (ABPBI) membranes prepared by low and high temperature casting

Phosphoric acid-doped membranes based in poly[2,5-benzimidazole] (ABPBI) were obtained by a new low temperature casting procedure and by the classical high temperature casting from methanesulfonic acid. These membranes, which can be suitable for application in direct methanol proton exchange membrane (PEM) fuel cells, were studied in relation with their phosphoric acid doping level by measuring the free and bonded acid. The water isotherms were also determined for the low and high temperature casted ABPBI membranes. Both, acid and water sorption properties, were compared with those determined in poly [2-2′-(m-fenylene)-5-5′ bibenzimidazole] (PBI) membranes. The water sorption of the ABPBI membranes over the range of all water activity is described by the modified BET equation, commonly known as Guggenheim–Anderson–de Boer (GAB) and a two-parameters empirical isotherm. The acid uptake behaviour of the membranes prepared by low and high temperature casting are related with differences in their supramolecular structure.     

In situ electrochemical generation of gold nanostructured screen-printed carbon electrodes. Application to the detection of lead underpotential deposition

In the present work, an electrochemical method for the reproducible and stable generation of gold nanostructures on the surface of screen-printed carbon electrodes was developed. This technique is based on the application of a constant current over an appropriate time interval. Gold nanostructured screen-printed carbon electrodes were characterized using both SEM and electrochemical methods. The mean diameter and the dispersion of gold nanoparticles that were generated electrochemically depended on the gold concentration, the time deposition and the current intensity. Smaller diameters and better distribution of nanoparticles were obtained when a shift of potential to −0.70 V occurred during the gold electrodeposition process. Moreover, the underpotential deposition (UPD) of lead on these nanostructured surfaces was studied, as was their behavior as array electrodes. The best results, using UPD combined with square wave stripping voltammetry, were obtained for gold nanostructured surfaces with a mean diameter of 78 ± 24 nm and a density of 4.4 × 10⁷ nanoparticles/mm². These gold nanostructured screen-printed carbon electrodes were obtained by applying a current intensity of −100 μA for 300 s using a gold concentration of 0.5 mM. The reproducibility and limit of detection obtained using these nanostructured electrodic surfaces were 2.4% (in terms of RSD) and 0.8 ng/mL, respectively.