402 research outputs found
The effect of a specialized dyslexia font, OpenDyslexic, on reading rate and accuracy
A single-subject alternating treatment design was used to investigate the extent to which a specialized dyslexia font, OpenDyslexic, impacted reading rate or accuracy compared to two commonly used fonts when used with elementary students identified as having dyslexia. OpenDyslexic was compared to Arial and Times New Roman in three reading tasks: (a) letter naming, (b) word reading, and (c) nonsense word reading. Data were analyzed through visual analysis and improvement rate difference, a nonparametric measure of nonoverlap for comparing treatments. Results from this alternating treatment experiment show no improvement in reading rate or accuracy for individual students with dyslexia, as well as the group as a whole. While some students commented that the font was "new" or "different", none of the participants reported preferring to read material presented in that font. These results indicate there may be no benefit for translating print materials to this font
Genetics of the yeast, Phaffia rhodozyma
The aim of this thesis is studying the genetics of Phaffia and to develop a genetic transformation system for this yeast. The genetic properties of Phaffia were studied on the gene and genome level.As a first step the molecular structure of the Phaffia actin gene was analyzed. Actin genes are highly conserved throughout nature, and as such they have been used for the classification of significantly diverging eukaryotic groups, like (in-)vertebrates, plants and fungi.We anticipated that the analysis of the primary structure of Phaffia actin gene and comparison with the actin genes from fungi, including 2 ascomycetous filamentous fungi, 2 basidiomycetous yeasts and 5 ascomycetous yeasts would provide further phylogenetic information on this yeast.It was found that the Phaffia actin gene encoded a protein consisting of 375 amino acids. In addition 4 (non-coding) intervening sequences were present. Comparison of both the coding DNA sequence and its predicted protein product with their fungal counterparts, revealed that least homology was found with the ascomycetous yeasts, like Saccharomyces cerevisiae and Kluyveromyces lactis . It was also shown, that based on these comparisons Phaffia is closer related to the filamentous ascomycetous fungi Thermomyces lanuginosus and Aspergillus nidulans , whereas most homology was found with the basidiomycetous yeast Filobasidiella neoformans (perfect stage of Cryptococcus neoformans ).In addition to the phylogenetic analysis of the actin exons, the architecture of the introns (splice site consensus sequences, size, position in the gene) was compared. it was shown that the Phaffia introns most resembled that of Filobasidiella neoformans where as least resemblance occurred with the ascomycetous yeasts. This result was in agreement with the actin exon homology studies. Furthermore, the presence of multiple introns in the Phaffia actin gene resembled the situation in the actin genes from F. neoformans and the filamentous fungi, whereas the ascomycetous yeasts only carry one intron in their actin genes.Similar results were obtained by (phylo-)genetic analysis of the five introns containing Phaffia glyceraldehyde-3-phosphate dehydrogenase gene.The genomic organization of the multiple rDNA genes in Phaffia was elucidated. It was found that Phaffia carries the rDNA genes in three clusters, of 12, 14 and 35 copies, on three different chromosomes. In the ascomycetous yeasts and fungi the rDNA is mainly present on one chromosome.The significant differences on the gene and genome level with the ascomycetous yeasts affected the strategy for the development of a transformation system for Phaffia . Whereas several marker gene sequences or sequences for plasmid replication and maintenance can be readily interchanged between most ascomycetous species as a result of high homologies, it was shown that this was not the case for Phaffia . Therefore an almost entirely homologous transformation sytem was developed using plasmids carrying the dominant G418 resistance gene (Km R), driven by either the Phaffia actin or the gpd promoter and a Phaffia ribosomal DNA (rDNA) fragment for homologous integration.It was found that the rDNA clusters could serve as a target for high copy number integration. This integrative transformation system was used to determine the ploidy of Phaffia , strain CBS 6938, by monitoiring chromosomal shifts as a result of multiple integrations. It was found that this strain was haploid.Plasmids carrying the gpd promoter driven Km Rgene transformed Phaffia with significant higher efficiencies than constructs with the actin promoter. Furthermore, the plas-mid copy number and transformation efficiencies of the first were found to be influenced by the presence of the gpd terminator downstream the Km Rgene.It was shown that plasmid amplification occurred independent from selection pressure to an extend that appeared to be negatively related to the effectiveness of expression of the Km Rgene. This observation indicated that the rising metabolic burden, as a consequence of amplification, imposes limits to the number of plasmid copies.The effectiveness, stability, and plasmid amplifying properties of the Phaffia transformation system offer possibilities for the use of recombinant DNA technology in developing industrially attractive Phaffia strains
Sustainable Intensification of Mixed Farming Systems Initiative: Observations from the work package and country-based group planning exercise
Transcriptome analysis of a phenol-producing Pseudomonas putida S12 construct: Genetic and physiological basis for improved production
The unknown genetic basis for improved phenol production by a recombinant Pseudomonas putida S12 derivative bearing the tpl (tyrosine-phenol lyase) gene was investigated via comparative transcriptomics, nucleotide sequence analysis, and targeted gene disruption. We show upregulation of tyrosine biosynthetic genes and possibly decreased biosynthesis of tryptophan caused by a mutation in the trpE gene as the genetic basis for the enhanced phenol production. In addition, several genes in degradation routes connected to the tyrosine biosynthetic pathway were upregulated. This either may be a side effect that negatively affects phenol production or may point to intracellular accumulation of tyrosine or its intermediates. A number of genes identified by the transcriptome analysis were selected for targeted disruption in P. putida S12TPL3. Physiological and biochemical examination of P. putida S12TPL3 and these mutants led to the conclusion that the metabolic flux toward tyrosine in P. putida S12TPL3 was improved to such an extent that the heterologous tyrosine-phenol lyase enzyme had become the rate-limiting step in phenol biosynthesis. Copyright © 2008, American Society for Microbiology. All Rights Reserved
A new parametric speech analysis and synthesis technique in the frequency domain
This article describes a new approach for parametric analysis and synthesis of speech . It is based on the frequency domain
modelling of the residual signal of an LPC analysis, including an harmonie structure and pitch extraction, and a sub-band
analysis in order to détermine a «voiced-unvoiced ratio» variable with frequency .
This residue parametric representation is added to the classical LPC parameters for transmission or memorisation .
Our system présents of course the flexibility of parametrical systems and is well adapted to frame to frame transition problems
encountered.in text-to-speech applications .Cet article présente une nouvelle approche de l'analyse et de la synthèse paramétriques de la parole basée sur l'élaboration
d'un modèle du résidu du filtre inverse de la prédiction linéaire dans le domaine fréquentiel . Ce modèle fait intervenir la
recherche d'une structure harmonique et de la période fondamentale, l'analyse en sous-bandes du signal pour la détermination
de «proportions de voisement» de sorte à rendre la décision voisé-non voisé progressive et fonction de la fréquence .
Cette représentation paramétrique du signal résiduel est associée aux paramètres LPC habituels pour la transmission ou la
mémorisation.
Le système ainsi créé présente la souplesse des systèmes paramétriques et est bien adapté aux problèmes de connexion entre
trames intervenant dans les applications de synthèse à partir du texte
Deep Brain Stimulation of the Subthalamic Nucleus Improves Reward-Based Decision-Learning in Parkinson's Disease
Recently, the subthalamic nucleus (STN) has been shown to be critically involved in decision-making, action selection, and motor control. Here we investigate the effect of deep brain stimulation (DBS) of the STN on reward-based decision-learning in patients diagnosed with Parkinson's disease (PD). We determined computational measures of outcome evaluation and reward prediction from PD patients who performed a probabilistic reward-based decision-learning task. In previous work, these measures covaried with activation in the nucleus caudatus (outcome evaluation during the early phases of learning) and the putamen (reward prediction during later phases of learning). We observed that stimulation of the STN motor regions in PD patients served to improve reward-based decision-learning, probably through its effect on activity in frontostriatal motor loops (prominently involving the putamen and, hence, reward prediction). In a subset of relatively younger patients with relatively shorter disease duration, the effects of DBS appeared to spread to more cognitive regions of the STN, benefiting loops that connect the caudate to various prefrontal areas importantfor outcome evaluation. These results highlight positive effects of STN stimulation on cognitive functions that may benefit PD patients in daily-life association-learning situations
Genomotyping of Pseudomonas putida strains using P. putida KT2440-based high-density DNA microarrays: implications for transcriptomics studies
Pseudomonas putida KT2440 is the only fully sequenced P. putida strain. Thus, for transcriptomics and proteomics studies with other P. putida strains, the P. putida KT2440 genomic database serves as standard reference. The utility of KT2440 whole-genome, high-density oligonucleotide microarrays for transcriptomics studies of other Pseudomonas strains was investigated. To this end, microarray hybridizations were performed with genomic DNAs of subcultures of P. putida KT2440 (DSM6125), the type strain (DSM291T), plasmid pWW0-containing KT2440-derivative strain mt-2 (DSM3931), the solvent-tolerant P. putida S12, and several other Pseudomonas strains. Depending on the strain tested, 22 to 99% of all genetic elements were identified in the genomic DNAs. The efficacy of these microarrays to study cellular function was determined for all strains included in the study. The vast majority of DSM6125 genes encoding proteins of primary metabolism and genes involved in the catabolism of aromatic compounds were identified in the genomic DNA of strain S12: a prerequisite for reliable transcriptomics analyses. The genomotypic comparisons between Pseudomonas strains were used to construct highly discriminative phylogenetic relationships. DSM6125 and DSM3931 were indistinguishable and clustered together with strain S12 in a separate group, distinct from DSM291T. Pseudomonas monteilii (DSM14164) clustered well with P. putida strains
Investigation of whisker growth from alkaline non-cyanide zinc electrodeposits
Electroplated zinc finishes have been widely used in the packaging of electronic products for many years as a result of their excellent corrosion resistance and relatively low cost. However, the spontaneous formation of whiskers on zinc electroplated components, which are capable of resulting in electrical shorting or other damaging effects, can be highly problematic for the reliability of long-life electrical and electronic equipment. This work investigated the mechanism for whisker growth from zinc electrodeposited mild steel substrates. The incubation time for whisker growth from the surface of nodules on the surface of the electrodeposit was considerably reduced compared with that from the planar deposit surface. Recrystallisation of the as-deposited columnar structure was observed at the whisker root. This result is consistent with some recent whisker growth models based on recrystallisation. There was no evidence of iron-zinc (Fe-Zn) intermetallic formation at the iron/zinc (Fe/Zn) interface or within the zinc coating beneath the whiskers
Tradeoff between Biomass and Flavonoid Accumulation in White Clover Reflects Contrasting Plant Strategies
An outdoor study was conducted to examine relationships between plant productivity and stress-protective phenolic plant metabolites. Twenty-two populations of the pasture legume white clover were grown for 4½ months during spring and summer in Palmerston North, New Zealand. The major phenolic compounds identified and quantified by HPLC analysis were glycosides of the flavonoids quercetin and kaempferol. Multivariate analysis revealed a trade-off between flavonoid accumulation and plant productivity attributes. White clover populations with high biomass production, large leaves and thick tap roots showed low levels of quercetin glycoside accumulation and low quercetin:kaempferol ratios, while the opposite was true for less productive populations. The latter included stress-resistant ecotypes from Turkey and China, and the analysis also identified highly significant positive relationships of quercetin glycoside accumulation with plant morphology (root:shoot ratio). Importantly, a high degree of genetic variation was detected for most of the measured traits. These findings suggest merit for considering flavonoids such as quercetin as potential selection criteria in the genetic improvement of white clover and other crops
Distinct Roles of Non-Canonical Poly(A) Polymerases in RNA Metabolism
Trf4p and Trf5p are non-canonical poly(A) polymerases and are part of the heteromeric protein complexes TRAMP4 and TRAMP5 that promote the degradation of aberrant and short-lived RNA substrates by interacting with the nuclear exosome. To assess the level of functional redundancy between the paralogous Trf4 and Trf5 proteins and to investigate the role of the Trf4-dependent polyadenylation in vivo, we used DNA microarrays to compare gene expression of the wild-type yeast strain of S. cerevisiae with either that of trf4Δ or trf5Δ mutant strains or the trf4Δ mutant expressing the polyadenylation-defective Trf4(DADA) protein. We found little overlap between the sets of transcripts with altered expression in the trf4Δ or the trf5Δ mutants, suggesting that Trf4p and Trf5p target distinct groups of RNAs for degradation. Surprisingly, most RNAs the expression of which was altered by the trf4 deletion were restored to wild-type levels by overexpression of TRF4(DADA), showing that the polyadenylation activity of Trf4p is dispensable in vivo. Apart from previously reported Trf4p and Trf5p target RNAs, this analysis along with in vivo cross-linking and RNA immunopurification-chip experiments revealed that both the TRAMP4 and the TRAMP5 complexes stimulate the degradation of spliced-out introns via a mechanism that is independent of the polyadenylation activity of Trf4p. In addition, we show that disruption of trf4 causes severe shortening of telomeres suggesting that TRF4 functions in the maintenance of telomere length. Finally, our study demonstrates that TRF4, the exosome, and TRF5 participate in antisense RNA–mediated regulation of genes involved in phosphate metabolism. In conclusion, our results suggest that paralogous TRAMP complexes have distinct RNA selectivities with functional implications in RNA surveillance as well as other RNA–related processes. This indicates widespread and integrative functions of TRAMP complexes for the coordination of different gene expression regulatory processes
- …