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Cet article juxtapose les developpements d'une theorie mondiale en opposition avec les developpements d'une pensee critique sur les relations de classe. Alors que certains specialistes des deux bords se debattent de facon similaire avec le determinisme economique et se tournent vers l'education pour expliquer la structuration inequitable des relations, les reflexions divergent quant aux problemes d'action des classes subordonnees. Le but de cet essai est de lier ces deux champs de pensee et de suggerer un programme d'action pour une recherche mondiale en education comparee.

This paper analyzes the explanations suggested by language and educational policy scholars for the use of languages of wider communication in education in developing countries. Five explanations are discussed and critiqued, namely national integration, comparative cost, international communication, elite closure, and the world-system; each explanation is driven by assumptions about the nature of society (functional or radical-functional) and the level at which ‘society’ operates (national or international). Too narrow an adherence to a particular configuration of assumptions may foreclose for scholars a broad understanding of the dynamics which inform language policy decisions in developing countries.

The heat capacity of poly-p-dioxanone (PPDX), (CH2[sbnd]CH2[sbnd]O[sbnd]CH2[sbnd]COO[sbnd])x, was determined using both differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC) from 200 K to 430 K. Based on the new data and literature data, the heat capacity of the solid state was analyzed using an approximate group vibrational spectrum and skeletal vibrations. The 10 skeletal vibrational modes are well represented by a Tarasov function with theta temperatures of θ1 = 478.7 K and θ3 = 50.4 K. The heat capacity of the liquid was fitted to a linear function, C liquid = 0.1484 T + 144.3 in units of J K−1 mol−1, which is close to the sum of equations developed earlier for the liquids of poly(oxyethylene) and polyglycolide. The change in heat capacity of amorphous PPDX at the glass transition temperature (264 K) is 69.9 J K−1 mol−1, and the heat of fusion for perfect crystals at the melting temperature (≈400 K) is 14.4 kJ mol−1. The integral thermodynamic functions were derived, a...

This paper discusses three scientific traditions (positivist, interpretivist and critical) as they inform methodological and strategic choices within a USAID‐funded ‘Improving Educational Quality’ project in Ghana, Guatemala and Mali. These scientific traditions are shown not only to frame choices in posing research questions and selecting data‐gathering and analysis strategies, but also to orient decisions about approaches for linking research to policy and practice and for establishing relationships between researchers and policy‐makers and practitioners. Special consideration is given to these issues as they inform classroom‐anchored research undertaken by and for educational personnel in ‘developing’ countries.

The Wavefront Topology System (WTS) is a novel algorithm for numerical analysis in computational geometry and electromagnetics. WTS is capable of generating continuous finite elements for discrete subdivision of arbitrary geometrical domains. Structured grids are achievable by a topological algorithm which is invariant to the coordinate system associated with the physical region. The generated grid topology corresponds to an orthogonal coordinate system. The assembly of nodes and edges within this topology form elements. These elements exist in a functional space; and all continuous functions in the functional space are represented as a linear combination of basis functions. The WTS algorithm generates basis functions in cartesian, spherical, cylindrical, and toroidal coordinate systems. The preprocessing phase provides a robust methodology for solving the partial differential equation associated with the physical geometry; post process rendering is also enhanced by this technique. The WTS advancing systematic node insertion process propagates through the interior of the domain. The front travels until boundary conditions are satisfied; constraints are geometrical. Volumes and surfaces are candidates for automatic polygon generation. Global and local coordinates are furnished as the topology advances in an outward propagation. Insertion of coordinates are subjected to a 1st, 2nd, and 3rd order adjacency matrix. The WTS method intrinsically supports numerical quadrature and finite difference analysis for solving integral and partial differential equations. The algorithm begins with a stencil initialization process then proceeds with a node insertion technique. The insertion process results in the creation of a discrete computational lattice. Hybridization with the Finite Element Method (FEM) will demonstrate its functionality as an efficient FEM code. Its integration with current engineering FEM methodologies provides a numerical technique for solving linear systems of equations of the form Ax=b. An exposition of the research will explore a Laplace analysis of voltage distribution. The research will also involve electromagnetic (EM) scattering from a dielectric cylinder. The previous work will include WTS applications to image processing and molecular modeling. The challenge will include a comparison of computation complexity and time for different solutions within complex geometrical domains. The solutions will be displayed in a custom developed scientific visualization system. This research demonstrates the significance of the WTS analysis to copious fields of computational engineering. The WTS technique optimizes preprocessing, solving, and postprocessing.

Background/introduction Hepatitis C (HCV) is an important blood-borne virus in the UK with high morbidity/mortality. Injecting drug use has traditionally been seen as the most important risk factor for transmission in Britain, but since 2000 there has been an emergent rise in infection rates amongst HIV-positive men who have sex with men (MSM). This is thought to be driven by risky sexual/drug taking behaviours. Aim(s)/objectives Review viral response of acute HCV infections after treatment with current NICE approved therapy. Methods A prospective case note review was performed of patients diagnosed with acute HCV between 2004–2015. Results There were 102 acute HCV infections. Median age 37, (range 20–61), all cases were male and MSM. 91 (89%) patients had Genotype 1 infection, and 98 (96%) were co-infected with HIV. 36 (35%) patients had a history of injecting drug use. 20 patients were initiated on pegylated interferon/ribavirin within 6 months of diagnosis. Discussion/conclusion Only 4 (20%) acute HCV patients achieved simultaneous RVR/SVR within 6 months of diagnosis (PPV = 100%). Novel direct acting antivirals (DAAs) have SVR rates above 90%; this alone is a compelling reason to promote DAAs in managing the burden of HCV infection thus reducing propensity for onward transmission.

This paper presents a novel substitution matrix loader architecture for pairwise sequence alignment. The search for sequence homology using DP-based alignment matrix computation is an important tool in molecular biology. It can be implemented either by optimal or sub-optimal approaches. Both of these methods require frequent and rapid access to the amino acids probability scores for PE (Processing Element) configuration especially in a folded systolic array. Typical FPGA implementations configure look-up tables in the pipeline PEs either by using a serial configuration chain with different look-up tables or by run time reconfiguration of the same look-up table. In the former case, configuration time increases proportionally to the number of look-up tables, while the latter case suffers from the limited reconfiguration bandwidth. Therefore, in this paper, we propose a highly efficient parallel loader to optimize both time and space complexities of protein sequence alignment in folded systolic arrays, using only two configuration elements (CEs). In addition, the proposed loader enables PEs to be updated with substitution matrix scores concurrently, with the worst case configuration time of 2 × the depth of the PE's look-up table (in clock cycles). This allows for further optimization of the most time consuming alignment matrix computation through efficient scheduling of alignment matrix computation and PE configuration. Implementation results show that the proposed architecture achieves k.N PE speed-up in configuration time (where k is the folding factor and N PE is the number of PEs) compared to classical approaches, at virtually no area overhead.

A substantial proportion of the broadly neutralizing antibodies (bnAbs) identified in certain HIV-infected donors recognize glycan-dependent epitopes on HIV-1 gp120. Here we elucidate how the bnAb PGT 135 binds its Asn332 glycan-dependent epitope from its 3.1-angstrom crystal structure with gp120, CD4 and Fab 17b. PGT 135 interacts with glycans at Asn332, Asn392 and Asn386, using long CDR loops H1 and H3 to penetrate the glycan shield and access the gp120 protein surface. EM reveals that PGT 135 can accommodate the conformational and chemical diversity of gp120 glycans by altering its angle of engagement. Combined structural studies of PGT 135, PGT 128 and 2G12 show that this Asn332-dependent antigenic region is highly accessible and much more extensive than initially appreciated, which allows for multiple binding modes and varied angles of approach; thereby it represents a supersite of vulnerability for antibody neutralization

Contact angles of various oils and chocolate syrup were estimated on a commercial brand of white sandwich bread and a commercial brand of butter cookies using three different methods: sessile drop geometry, sedimentation volume and immersion techniques. It was concluded that estimation of contact angles from the sessile drop geometry by photographic techniques is not possible for oils due to absorption into the starch-based solid. In such cases, the sedimentation volume and immersion techniques were found to be practical methods for rough estimates of contact angles when needed. For the non-Newtonian chocolate syrup, estimation of contact angles with the starch-based solids by sedimentation volume was not possible due to the yield stress of chocolate syrup. However, in this case, contact angles could be estimated from sessile drop geometry.

The crystal structure of an essential bacterial protein, YeaZ, from T. maritima identifies an interface that potentially mediates protein–protein interaction., YeaZ is involved in a protein network that is essential for bacteria. The crystal structure of YeaZ from Thermotoga maritima was determined to 2.5 Å resolution. Although this protein belongs to a family of ancient actin-like ATPases, it appears that it has lost the ability to bind ATP since it lacks some key structural features that are important for interaction with ATP. A conserved surface was identified, supporting its role in the formation of protein complexes.

The crystal structure of an RmlC-type cupin with zinc acetate bound at the putative active site reveals significant differences from a previous structure without any bound ligand. The functional implications of the ligand-induced conformational changes are discussed., In the plant pathogen Xanthomonas campestris pv. campestris, the product of the tcmJ gene, XcTcmJ, encodes a protein belonging to the RmlC family of cupins. XcTcmJ was crystallized in a monoclinic space group (C2) in the presence of zinc acetate and the structure was determined to 1.6 Å resolution. Previously, the apo structure has been reported in the absence of any bound metal ion [Chin et al. (2006 ▶), Proteins, 65, 1046–1050]. The most significant difference between the apo structure and the structure of XcTcmJ described here is a reorganization of the binding site for zinc acetate, which was most likely acquired from the crystallization solution. This site is located in the conserved metal ion-binding domain at the putative active site of XcTcmJ. In addition, an acetate was also bound within coordination distance of the zinc. In order to accommodate this binding, rearrangement of a conserved histidine ligand is required as well as several nearby residues within and around the putative active site. These observations indicate that binding of zinc serves a functional role in this cupin protein.

The crystal structure of the highly specific γ-d-glutamyl-l-diamino acid endopeptidase YkfC from Bacillus cereus in complex with l-Ala-γ-d-Glu reveals the structural basis for the substrate specificity of NlpC/P60-family cysteine peptidases., Dipeptidyl-peptidase VI from Bacillus sphaericus and YkfC from Bacillus subtilis have both previously been characterized as highly specific γ-d-glutamyl-l-­diamino acid endopeptidases. The crystal structure of a YkfC ortholog from Bacillus cereus (BcYkfC) at 1.8 Å resolution revealed that it contains two N-terminal bacterial SH3 (SH3b) domains in addition to the C-terminal catalytic NlpC/P60 domain that is ubiquitous in the very large family of cell-wall-related cysteine peptidases. A bound reaction product (l-Ala-γ-d-Glu) enabled the identification of conserved sequence and structural signatures for recognition of l-Ala and γ-d-Glu and, therefore, provides a clear framework for understanding the substrate specificity observed in dipeptidyl-peptidase VI, YkfC and other NlpC/P60 domains in general. The first SH3b domain plays an important role in defining substrate specificity by contributing to the formation of the active site, such that only murein peptides with a free N-terminal alanine are allowed. A conserved tyrosine in the SH3b domain of the YkfC subfamily is correlated with the presence of a conserved acidic residue in the NlpC/P60 domain and both residues interact with the free amine group of the alanine. This structural feature allows the definition of a subfamily of NlpC/P60 enzymes with the same N-terminal substrate requirements, including a previously characterized cyanobacterial l-­alanine-γ-d-glutamate endopeptidase that contains the two key components (an NlpC/P60 domain attached to an SH3b domain) for assembly of a YkfC-like active site.

The crystal structures of two orthologous proteins from different Shewanella species have uncovered a resemblance to CRAL-TRIO carrier proteins, which suggest that they function as transporters of small nonpolar molecules. One protein adopts an open conformation, while the other adopts a closed structure that may act as a conformational switch in the transport of ligands at the membrane surface., The crystal structures of the proteins encoded by the YP_749275.1 and YP_001095227.1 genes from Shewanella frigidimarina and S. loihica, respectively, have been determined at 1.8 and 2.25 Å resolution, respectively. These proteins are members of a novel family of bacterial proteins that adopt the α/β SpoIIAA-like fold found in STAS and CRAL-TRIO domains. Despite sharing 54% sequence identity, these two proteins adopt distinct conformations arising from different dispositions of their α2 and α3 helices. In the ‘open’ conformation (YP_001095227.1), these helices are 15 Å apart, leading to the creation of a deep nonpolar cavity. In the ‘closed’ structure (YP_749275.1), the helices partially unfold and rearrange, occluding the cavity and decreasing the solvent-exposed hydrophobic surface. These two complementary structures are reminiscent of the conformational switch in CRAL-TRIO carriers of hydrophobic compounds. It is suggested that both proteins may associate with the lipid bilayer in their ‘open’ monomeric state by inserting their amphiphilic helices, α2 and α3, into the lipid bilayer. These bacterial proteins may function as carriers of nonpolar substances or as interfacially activated enzymes.

The crystal structure of the first representative of the Pfam PF07336 (DUF1470) family reveals a two-domain organization that contains a new fold, termed the ABATE domain, at the N-terminus and a treble-clef zinc finger that is likely to bind DNA at the C-terminus., The crystal structure of Jann_2411 from Jannaschia sp. strain CCS1, a member of the Pfam PF07336 family classified as a domain of unknown function (DUF1470), was solved to a resolution of 1.45 Å by multiple-wavelength anomalous dispersion (MAD). This protein is the first structural representative of the DUF1470 Pfam family. Structural analysis revealed a two-domain organization, with the N-terminal domain presenting a new fold called the ABATE domain that may bind an as yet unknown ligand. The C-terminal domain forms a treble-clef zinc finger that is likely to be involved in DNA binding. Analysis of the Jann_2411 protein and the broader ABATE-domain family suggests a role as stress-induced transcriptional regulators.

The crystal structure of tryptophanyl-tRNA synthetase from T. maritima unexpectedly revealed an iron–sulfur cluster bound to the tRNA anticodon-binding region., A novel aminoacyl-tRNA synthetase that contains an iron–sulfur cluster in the tRNA anticodon-binding region and efficiently charges tRNA with tryptophan has been found in Thermotoga maritima. The crystal structure of TmTrpRS (tryptophanyl-tRNA synthetase; TrpRS; EC 6.1.1.2) reveals an iron–sulfur [4Fe–­4S] cluster bound to the tRNA anticodon-binding (TAB) domain and an l-­tryptophan ligand in the active site. None of the other T. maritima aminoacyl-tRNA synthetases (AARSs) contain this [4Fe–4S] cluster-binding motif (C-x 22-C-x 6-C-x 2-C). It is speculated that the iron–sulfur cluster contributes to the stability of TmTrpRS and could play a role in the recognition of the anticodon.

The crystal structure of the BVU2987 gene product from B. vulgatus (UniProt A6L4L1) reveals that members of the new Pfam family PF11396 (domain of unknown function; DUF2874) are similar to β-lactamase inhibitor protein and YpmB., Proteins that contain the DUF2874 domain constitute a new Pfam family PF11396. Members of this family have predominantly been identified in microbes found in the human gut and oral cavity. The crystal structure of one member of this family, BVU2987 from Bacteroides vulgatus, has been determined, revealing a β-lactamase inhibitor protein-like structure with a tandem repeat of domains. Sequence analysis and structural comparisons reveal that BVU2987 and other DUF2874 proteins are related to β-lactamase inhibitor protein, PepSY and SmpA_OmlA proteins and hence are likely to function as inhibitory proteins.

NE1406, the first structural representative of PF09410, reveals a lipocalin-like fold with features that suggest involvement in lipid metabolism. In addition, NE1406 provides potential structural templates for two other protein families (PF07143 and PF08622)., The first structural representative of the domain of unknown function DUF2006 family, also known as Pfam family PF09410, comprises a lipocalin-like fold with domain duplication. The finding of the calycin signature in the N-­terminal domain, combined with remote sequence similarity to two other protein families (PF07143 and PF08622) implicated in isoprenoid metabolism and the oxidative stress response, support an involvement in lipid metabolism. Clusters of conserved residues that interact with ligand mimetics suggest that the binding and regulation sites map to the N-terminal domain and to the interdomain interface, respectively.

The crystal structure of the first representative of DUF364 family reveals a combination of enolase N-terminal-like and C-terminal Rossmann-like folds. Analysis of the interdomain cleft combined with sequence and genome context conservation among homologs, suggests a unique catalytic site likely involved in the synthesis of a flavin or pterin derivative., The crystal structure of Dhaf4260 from Desulfitobacterium hafniense DCB-2 was determined by single-wavelength anomalous diffraction (SAD) to a resolution of 2.01 Å using the semi-automated high-throughput pipeline of the Joint Center for Structural Genomics (JCSG) as part of the NIGMS Protein Structure Initiative (PSI). This protein structure is the first representative of the PF04016 (DUF364) Pfam family and reveals a novel combination of two well known domains (an enolase N-terminal-like fold followed by a Rossmann-like domain). Structural and bioinformatic analyses reveal partial similarities to Rossmann-like methyltransferases, with residues from the enolase-like fold combining to form a unique active site that is likely to be involved in the condensation or hydrolysis of molecules implicated in the synthesis of flavins, pterins or other siderophores. The genome context of Dhaf4260 and homologs additionally supports a role in heavy-metal chelation.

Structures of the first representatives of PF06684 (DUF1185) reveal a Bacillus chorismate mutase-like fold with a potential role in amino-acid synthesis., The crystal structures of BB2672 and SPO0826 were determined to resolutions of 1.7 and 2.1 Å by single-wavelength anomalous dispersion and multiple-wavelength anomalous dispersion, respectively, using the semi-automated high-throughput pipeline of the Joint Center for Structural Genomics (JCSG) as part of the NIGMS Protein Structure Initiative (PSI). These proteins are the first structural representatives of the PF06684 (DUF1185) Pfam family. Structural analysis revealed that both structures adopt a variant of the Bacillus chorismate mutase fold (BCM). The biological unit of both proteins is a hexamer and analysis of homologs indicates that the oligomer interface residues are highly conserved. The conformation of the critical regions for oligomerization appears to be dependent on pH or salt concentration, suggesting that this protein might be subject to environmental regulation. Structural similarities to BCM and genome-context analysis suggest a function in amino-acid synthesis.

Poisson distributed spike trains are often used as the input to VLSI implementations of spiking neural networks. However, it can be difficult to generate large truly random spike distributions which can be easily applied as input to a chip. This work presents results recorded from an avalanche photo diode which demonstrates that it can be used to create a Poisson distributed spike train and describes the circuitry which will allow it to interface with other neuromorphic chips using the Address Event Representation protocol. The chip is currently being fabricated using the AMS 0.35µm HV process.

The crystal structure of a putative NTP pyrophosphohydrolase, YP_001813558.1 from E. sibiricum, reveals a novel segment-swapped linked-dimer assembly., The crystal structure of a putative NTPase, YP_001813558.1 from Exiguo­bacterium sibiricum 255-15 (PF09934, DUF2166) was determined to 1.78 Å resolution. YP_001813558.1 and its homologs (dimeric dUTPases, MazG proteins and HisE-encoded phosphoribosyl ATP pyrophosphohydrolases) form a superfamily of all-α-helical NTP pyrophosphatases. In dimeric dUTPase-like proteins, a central four-helix bundle forms the active site. However, in YP_001813558.1, an unexpected intertwined swapping of two of the helices that compose the conserved helix bundle results in a ‘linked dimer’ that has not previously been observed for this family. Interestingly, despite this novel mode of dimerization, the metal-binding site for divalent cations, such as magnesium, that are essential for NTPase activity is still conserved. Furthermore, the active-site residues that are involved in sugar binding of the NTPs are also conserved when compared with other α-helical NTPases, but those that recognize the nucleotide bases are not conserved, suggesting a different substrate specificity.

Within the field of neural electrophysiology, there exists a divide between experimentalists and computational modellers. This is caused by the different spheres of expertise required to perform each discipline, as well as the differing resource requirements of the two parties. This paper considers several forms of hardware acceleration for implementation within a laboratory alongside time sensitive experimentation, and focuses on how the use of general purpose computation on graphics processing units (GP-GPU) can allow parameter estimation to be performed in the laboratory, thereby acting as a bridge between the two halves of this field.This would facilitate rapid iterative model design, as well as allowing new forms of experimentation. This discussion is concluded with a brief case study that reports the performance increases associated with a GPU implementation over a single CPU approach. It should be noted that the proposed paradigm is not limited to neuroscience, as it would be beneficial to any discipline where unreliable time sensitive experimental procedures dominate exploration of the field.

Crystal structures of two homologous peptidases from cyanobacteria Anabaena variabilis and Nostoc punctiforme at 1.05 A and 1.60 A resolution represent the first structures of a large class of cell-wall, cysteine peptidases that contain an N-terminal bacterial SH3-like domain (SH3b) and a C-terminal NlpC/P60 cysteine peptidase domain. The NlpC/P60 domain is a primitive, papain-like peptidase in the CA clan of cysteine peptidases with a Cys126/His176/His188 catalytic triad and a conserved catalytic core. We deduced from structure and sequence analysis, and then experimentally, that that these two proteins act as γ-D-glutamyl-L-diamino acid endopeptidases (EC 3.4.22.-). The active site is located near the interface between the SH3b and NlpC/P60 domains, where the SH3b domain may help define substrate specificity, instead of functioning as a targeting domain, so that only muropeptides with an N-terminal L-alanine can bind to the active site.

ECX21941 represents a very large family (over 600 members) of novel, ocean metagenome–specific proteins identified by clustering of the dataset from the Global Ocean Sampling expedition. The crystal structure of ECX21941 reveals unexpected similarity to Sm/LSm proteins, which are important RNA-binding proteins, despite no detectable sequence similarity. The ECX21941 protein assembles as a homopentamer in solution and in the crystal structure when expressed in Escherichia coli and represents the first pentameric structure for this Sm/LSm family of proteins, although the actual oligomeric form in vivo is currently not known. The genomic neighborhood analysis of ECX21941 and its homologs combined with sequence similarity searches suggest a cyanophage origin for this protein. The specific functions of members of this family are unknown, but our structure analysis of ECX21941 indicates nucleic acid-binding capabilities and suggests a role in RNA and/or DNA processing.

SsgA-like proteins (SALPs) are a family of homologous cell division-related proteins that occur exclusively in morphologically complex actinomycetes. We show that SsgB, a subfamily of SALPs, is the archetypal SALP that is functionally conserved in all sporulating actinomycetes. Sporulation-specific cell division of Streptomyces coelicolor ssgB mutants is restored by introduction of distant ssgB orthologues from other actinomycetes. Interestingly, the number of septa (and spores) of the complemented null mutants is dictated by the specific ssgB orthologue that is expressed. The crystal structure of the SsgB from Thermobifida fusca was determined at 2.6 Å resolution and represents the first structure for this family. The structure revealed similarities to a class of eukaryotic “whirly” single-stranded DNA/RNA-binding proteins. However, the electro-negative surface of the SALPs suggests that neither SsgB nor any of the other SALPs are likely to interact with nucleotide substrates. Instead, we show that a conserved hydrophobic surface is likely to be important for SALP function and suggest that proteins are the likely binding partners.

Regulatory inactivation of DnaA is dependent on Hda (homologous to DnaA), a protein homologous to the AAA+ (ATPases associated with diverse cellular activities) ATPase region of the replication initiator DnaA. When bound to the sliding clamp loaded onto duplex DNA, Hda can stimulate the transformation of active DnaA-ATP into inactive DnaA-ADP. The crystal structure of Hda from Shewanella amazonensis SB2B at 1.75 A resolution reveals that Hda resembles typical AAA+ ATPases. The arrangement of the two subdomains in Hda (residues 1-174 and 175-241) differs dramatically from that of DnaA. A CDP molecule anchors the Hda domains in a conformation that promotes dimer formation. The Hda dimer adopts a novel oligomeric assembly for AAA+ proteins in which the arginine finger, crucial for ATP hydrolysis, is fully exposed and available to hydrolyze DnaA-ATP through a typical AAA+ type of mechanism. The sliding clamp binding motifs at the N-terminus of each Hda monomer are partially buried and combine to form an antiparallel beta-sheet at the dimer interface. The inaccessibility of the clamp binding motifs in the CDP-bound structure of Hda suggests that conformational changes are required for Hda to form a functional complex with the clamp. Thus, the CDP-bound Hda dimer likely represents an inactive form of Hda.

This paper compares three common evolutionary algorithms and our modified GA, a Distributed Adaptive Genetic Algorithm (DAGA). The optimal approach is sought to adapt, in near real-time, biological model behaviour to that of real biology within a laboratory. Near real-time adaptation is achieved with a Graphics Processing Unit (GPU). This, together with evolutionary computation, enables new forms of experimentation such as online testing, where biology and computational model are simultaneously stimulated and their responses compared. Rapid analysis and validation provide a platform that is required for rapid prototyping, and along with online testing, can provide new insight into the cause of biological behaviour. In this context, results demonstrate that our DAGA implementation is more efficient than the other three evolutionary algorithms due to its suitability to the adaptation environment, namely the large population sizes promoted by the GPU architecture.

A reprint of the main part of the editorial of‘Cross Currents: An International Journal of Language Teaching and Cross-Cultural Communication’, a Publication of the Language Institute of Japan, Vol. XVI, No. 2, 1989. Both ‘Cross-Currents' and ‘English Today’ welcome readers' comments, which could appear in future issues of both periodicals.

BtDyP from Bacteroides thetaiotaomicron (strain VPI-5482) and TyrA from Shewanella oneidensis are dye-decolorizing peroxidases (DyPs), members of a new family of heme-dependent peroxidases recently identified in fungi and bacteria. Here, we report the crystal structures of BtDyP and TyrA at 1.6 and 2.7 Angstroms, respectively. BtDyP assembles into a hexamer, while TyrA assembles into a dimer; the dimerization interface is conserved between the two proteins. Each monomer exhibits a two-domain, {alpha}+{beta} ferredoxin-like fold. A site for heme binding was identified computationally, and modeling of a heme into the proposed active site allowed for identification of residues likely to be functionally important. Structural and sequence comparisons with other DyPs demonstrate a conservation of putative heme-binding residues, including an absolutely conserved histidine. Isothermal titration calorimetry experiments confirm heme binding, but with a stoichiometry of 0.3:1 (heme:protein).