In search of trustworthy information: a qualitative study of the search behavior of people with dyslexia in Norway

Universal Access in the Information Society - Access to trustworthy information is a premise for participation in a democratic society. However, locating useful and valid information may not be a...     

Dyslexic students in higher education and virtual learning environments: an exploratory study

This paper presents the results of an interview‐based study of the use of virtual learning environments (VLEs) among dyslexic students. Interviews were carried out with 12 informants who had been formally diagnosed as dyslexic. The informants were either enrolled in a university or college programme, or had graduated less than a year before the interview. The findings reveal that dyslexic students experience a number of challenges associated with VLE use, including information overload, imperfect word processing tools, inadequate search functions, and having to relate to more than one system at a time.     

Cr3C2-NiCr and WC-Ni thermal spray coatings as alternatives to hard chromium for erosion-corrosion resistance

Cr₃C₂-NiCr and WC-Ni coatings are widely used for wear applications at high and room temperature, respectively. Due to the high corrosion resistance of NiCr binder, Cr₃C₂-NiCr coatings are also used in corrosive environments. The application of WC-Ni coatings in corrosive media is not recommended due to the poor corrosion resistance of the (pure Ni) metallic matrix. It is well known that the addition of Cr to the metallic binder improves the corrosion properties. Erosion-corrosion performance of thermal spray coatings is widely influenced by ceramic phase composition, the size of ceramic particles and also the composition of the metallic binder. In the present work, two types of HVOF thermal spray coatings (Cr₃C₂-NiCr and WC-Ni) obtained with different spray conditions were studied and compared with conventional micro-cracked hard chromium coatings. Both as-sprayed and polished samples were tested under two erosion-corrosion conditions with different erosivity. Tungsten carbide coatings showed better performance under the most erosive condition, while chromium carbide coatings were superior under less erosive conditions. Some of the tungsten carbide coatings and hard chromium showed similar erosion-corrosion behaviour under more and less erosive conditions. The erosion-corrosion and electrochemical results showed that surface polishing improved the erosion-corrosion properties of the thermally sprayed coatings. The corrosion behaviour of the different coatings has been compared using Electrochemical Impedance Spectroscopy (EIS) and polarization curves. Total material loss due to erosion-corrosion was determined by weight loss measurements. An estimation of the corrosion contribution to the total weight loss was also given.     

The spectrum of Trp- mutants isolated as 5-fluoroanthranilate-resistant clones in Saccharomyces bayanus, S. mikatae and S. paradoxus

5-Fluoroanthranilic acid (FAA)-resistant mutants were selected in homothallic diploids of three Saccharomyces species, taking care to isolate mutants of independent origin. Mutations were assigned to complementation groups by interspecific complementation with S. cerevisiae tester strains. In all three species, trp3, trp4 and trp5 mutants were recovered. trp1 mutants were also recovered if the selection was imposed on a haploid strain. Thus, FAA selection may be more generally applicable than was previously described.     

Polypyrimidine tract-binding protein positively regulates inclusion of an alternative 3''-terminal exon

A leading candidate for a vaccine targeted at the erythrocytic stages of plasmodial parasite development is the merozoite surface protein-1 (MSP-1). We have previously shown that the carboxyl-terminal region of MSP-1 derived from Plasmodium yoelii yoelii 17XL, expressed as a fusion protein with glutathione S-transferase (GST-PYC2), can immunize mice against an otherwise lethal homologous challenge infection. This protection has been shown to be predominantly mediated by antibodies. We report here on the efficacy of immunization with MSP-1 carboxyl regions when the challenge is a heterologous rodent parasite species. The course of parasitemia was not altered in mice immunized with GST-PYC2 and challenged with 10(4) heterologous Plasmodium chabaudi adami parasites, as both control and immunized mice developed infections that peaked at day 7 and then rapidly declined. Similarly, mice immunized with GST-PYC2 and challenged with 10(5) Plasmodium berghei ANKA parasites displayed virulence similar to that seen in infection control mice. The homologous region of the P. chabaudi adami MSP-1 gene was similarly expressed as a fusion protein with GST. Mice immunized with GST-PCC2 and challenged with 10(4) parasites showed significant protection against homologous P. chabaudi adami infection but no protection whatsoever against heterologous P. yoelii yoelii 17XL infection. These in vivo results correlate with the observation that sera generated by immunization with the carboxyl region of MSP-1 recognizes this protein from homologous, but not heterologous, radiolabeled parasite protein preparations.     

Invagination in children]

Although rare, childhood intussusception is one of the most common causes of small bowel obstruction in infancy. In these very young patients it can sometimes be difficult to interpret the clinical signs and symptoms correctly. This retrospective study comprises 79 children (median age 7.5 months; 24% girls and 76% boys) who experienced 83 episodes of intussusception. At admission the diagnosis made by the referring physicians could be confirmed in only about one-third of the cases. A barium enema was part of the inhospital diagnostic process. Non-operative treatment was attempted in 70 patients (89%), and barium enema reduction was successful in 64%. Laparotomy was required in 33 (42%) of the patients. No mortality, bowel perforation, or any other major complications were encountered. The diagnosis of childhood intussusception seems difficult to achieve in many cases, and the interpretation of, at times vague clinical signs and symptoms remains a challenge for all clinicians who are involved in the care of these very young patients.     

Optimal Sorting of Raw Materials, Based on the Predicted End-Product Quality

Raw material variation is one of the most important factors causing unstable end-product quality. A methodology for sorting raw materials into homogenous groups with constant and optimized processing within each group is presented. The sorting criterion is based on the squared distance between the predicted response and its target value. The raw materials are split into homogenous categories by a partitioning algorithm related to the fuzzy-c-means algorithm. The method has been tested for raw material properties in one and two dimensions and with different degrees of fuzziness. The method shows good flexibility and can also be used with a penalty function penalizing unfavorable process settings.     

Erosion-corrosion properties of different WC-Co-Cr coatings deposited by the HVOF process—influence of metallic matrix composition and spray powder size distribution

WC-Co-Cr coatings were sprayed by the High Velocity Oxygen Fuel (HVOF) process and characterised by scanning electron microscopy (SEM), X-ray diffraction (XRD) and erosion corrosion tests. Powders with different relative amounts of Co and Cr in the matrix and different powder grain size distributions were examined. At constant spray conditions the powders gave coatings of different quality as regards erosion-corrosion performance. At low erosive conditions the erosion-corrosion resistance increased when increasing Cr-content from 5 to 8.5 wt.%. However, when the erosivity was increased by increasing test velocity, an increase of Cr content from 5 to 8.5 wt.% showed no improvement in coating quality. Powder grain size distribution was found to be an important parameter, strongly affecting the coating quality. Powders with narrow grain size distributions gave coatings of higher quality than powders with wider grain size distributions. A reduction of the heat input during spraying reduced the degree of WC decomposition and improved the coating properties when the spray powder contained a large fraction of small grains.     

A role for SRp54 during intron bridging of small introns with pyrimidine tracts upstream of the branch point

One of the earliest steps in pre-mRNA recognition involves binding of the splicing factor U2 snRNP auxiliary factor (U2AF or MUD2 in Saccharomyces cerevisiae) to the 3' splice site region. U2AF interacts with a number of other proteins, including members of the serine/arginine (SR) family of splicing factors as well as splicing factor 1 (SF1 or branch point bridging protein in S. cerevisiae), thereby participating in bridging either exons or introns. In vertebrates, the binding site for U2AF is the pyrimidine tract located between the branch point and 3' splice site. Many small introns, especially those in nonvertebrates, lack a classical 3' pyrimidine tract. Here we show that a 59-nucleotide Drosophila melanogaster intron contains C-rich pyrimidine tracts between the 5' splice site and branch point that are needed for maximal binding of both U1 snRNPs and U2 snRNPs to the 5' and 3' splice site, respectively, suggesting that the tracts are the binding site for an intron bridging factor. The tracts are shown to bind both U2AF and the SR protein SRp54 but not SF1. Addition of a strong 3' pyrimidine tract downstream of the branch point increases binding of SF1, but in this context, the upstream pyrimidine tracts are inhibitory. We suggest that U2AF- and/or SRp54-mediated intron bridging may be an alternative early recognition mode to SF1-directed bridging for small introns, suggesting gene-specific early spliceosome assembly.