A novel wide-pipeline low-density parity-check (LDPC) decoder approach for the worldwide interoperability for microwave access (WiMAX) standard (802.16e) is proposed for execution on field-programmable gate arrays (FPGAs), using a high-level synthesis tool to reduce the development effort and design validation time that generates a wide-pipeline architecture. Optimised open computing language (OpenCL)-based kernels are developed and the integration of distinct configurations of single instruction multiple data and compute units to increase the level of parallelism are analysed. The decoding throughput surpasses the minimal requirements of 75 Mbit/s, a key figure of merit that ranks the design with other very large-scale integration-based approaches. Furthermore, extra precision is deployed with 8-bit fixed-point arithmetic, delivering superior bit error rate performance and lower error floor regions.

In this work, four commercial nanoporous membranes (NF and NF90 from Filmtec (TM), and NP010 and NP030 from Microdyn Nadir) have been characterized and evaluated in order to use them to separate potassium clavulanate and potassium chloride. Their charge density has been investigated by Tangential Streaming Potential measurements for several concentrations of KCl and pH. The isoelectric point of the membranes has been found to be between pH 5.0 and 6.0. Their rejection for KCl has also been measured and the corresponding concentration polarization effect has been taken into account. Nanofiltration modeling, that considers the steric, electric and dielectric exclusion and the charge variation along the pores (SEDE-VCh model), satisfactorily describes the retention of KCl by using the dielectric constant inside the pores, epsilon(p), as the only fitting parameter. Although all the studied membranes are highly retentive for the potassium clavulanate, KCA, the most suitable membranes for KCA purification, attending to the KCl/KCA selectivity are NF or NF90 membranes at all pH. Lower pH values give higher selectivity for all the membranes. (C) 2011 Elsevier B.V. All rights reserved.

Temporary ponds are seasonal wetlands annually subjected to extreme and unstable ecological conditions, neither truly aquatic nor truly terrestrial. This habitat and its flora have been poorly studied and documented because of the ephemeral character of the flora, the changeable annual weather that has a great effect on the small, herbaceous taxa and the declining abundance of temporary ponds. The objectives of this study are: (a) to define plant community diversity in terms of floristic composition of ephemeral wetlands in SW Portugal, (b) to identify temporary pond types according to their vegetation composition and (c) to identify those ponds that configure the European community priority habitat (3170* - Mediterranean temporary ponds). Vegetation sampling was conducted in 29 ponds, identifying 168 species grouped among 15 plant communities. Soil texture, pH, organic C and N content were measured, but only N and percent of clay appear to be related with the distribution of each community type. The results showed that ephemeral wetlands could be classified into four type: vernal pools, marshlands, deep ponds and disturbed wetlands. Vernal pools correspond to the Mediterranean temporary ponds (3170*), protected as priority habitat under the EU Habitats Directive. Submersed Isoetes species (Isoetes setaceum and Isoetes velatum) represents, together with Eryngium corniculatum, the indicator species for vernal pools. We identify also indicator plant communities of this priority habitat, namely I. setaceum and E. corniculatum-Baldellia ranunculoides plant communities. In this region, the conservation of temporary ponds has so far been compatible with traditional agricultural activities, but today these ponds are endangered by the intensification of agriculture and the loss of traditional land use practices and by the development of tourism.

A video codec is described, based on several parallel digital signal processors which can be easily programmed to implement the H.261 algorithm and are organized as a single-instruction multiple-data computing architecture. Both the encoder and the decoder divide a picture in regions of horizontal strips and use one local processor per region. These local processors code (decode) one horizontal strip of data which, using the terminology of the H.261 standard, corresponds to two groups of blocks. They also communicate to a central processor which multiplexes (demultiplexes) the coded data from (for) the processors in the encoder (decoder). Lateral communication between adjacent processors is implemented to allow comparisons between blocks situated in neighbouring regions, as required by most motion estimation algorithms

The aim of this work is to determine the role of different metal contacts on the performances of one-dimensional thin-film position-sensitive detectors produced by plasma-enhanced chemical vapour deposition, to be used in optical rulers for alignment applications. The device consists on an indium tin oxide/p-i-n structure where the metal contacts used were based on Al, Al+Cu and Ag. The results achieved show that the contact mainly influences the final sensor range by limiting the magnitude of the analogue signals recorded. In spite of soldering problems the Al contact was the contact that lead to better discrimination of the sensor, with a nonlinearity of plusmn0.8% and a fall-off parameter of 3.2times10 -3. The Al+Cu contact also exhibits good performances (nonlinearity, of plusmn1.1%; fall-off parameter, 1.4times10 -2 cm -1) and should be chosen since it is much easier to solder but requires protection against oxidation. The integration of these sensors on the optical ruler lead to the production of a system with a response time below 0.5 ms, an accuracy better than plusmn1% and a mechanical precision of better than 0.25 mm in 100 mm, with full-scale noise below plusmn0.1%

Bioreactors utilising bacterially mediated sulphate reduction (BSR) have been widely tested for treating metal-rich waters, but sustained treatment of mobile metals (e.g. Zn) can be difficult to achieve in short residence time systems. Data are presented providing an assessment of alkalinity generating media (shells or limestone) and modes of metal removal in bioreactors receiving a synthetic acidic metal mine discharge (pH 2.7, Zn 15 mg/L, SO(4)(2-) 200 mg/L, net acidity 103 mg/L as CaCO(3)) subject to methanol dosing. In addition to alkalinity generating media (50%, v.v.), the columns comprised an organic matrix of softwood chippings (30%), manure (10%) and anaerobic digested sludge (10%). The column tests showed sustained alkalinity generation, which was significantly better in shell treatments. The first column in each treatment was effective throughout the 422 days in removing >99% of the dissolved Pb and Cu, and effective for four months in removing 99% of the dissolved Zn (residence time: 12-14 h). Methanol was added to the feedstock after Zn breakthrough and prompted almost complete removal of dissolved Zn alongside improved alkalinity generation and sulphate attenuation. While there was geochemical evidence for BSR, sequential extraction of substrates suggests that the bulk (67-80%) of removed Zn was associated with Fe-Mn oxide fractions. (C) 2011 Elsevier B.V. All rights reserved.