Seeing is knowing? Visual word recognition in non-dyslexic and dyslexic readers: an ERP study

The aim of the current study was to investigate whether phonological/semantic processing of the word takes place simultaneously with, or following, the early processing of its visual features. Event related potentials (ERPs) were recorded in 13 dyslexic (four female) and 14 non-dyslexic (six female) native English speaking young adults in two lexical decision tasks. In Task 1 participants had to make an orthographic lexical decision to distinguish frequently used words (W) from pseudohomophones (PH1)focusing on visual properties of stimuli. In Task 2 they had to make a phonological lexical decision—to pseudohomophones (PH2) and pseudowords (PW) and decide whether stimuli sounded like real words—focusing on non-visual higher order, i.e., phonological and semantic, processing of the stimuli. The behavioural performance was less good and the ERP peaks’ latency longer in dyslexics compared to controls. The reaction times (RTs) and the number of errors (reversed for the controls in Task 2) increased across four conditions for both groups in the following order: W< PH1< PH2< PW. The ERPs were larger in Task 2 compared to Task 1 starting at 100 ms (P1) for the controls and from about 220 ms (P2) for the dyslexics. The latency of N2 peak in left occipito-temporal sites was larger (as was the number of errors) in PH2 compared to PW condition in controls only, which indicates phonological/semantic specific processing at a time latency of 250–260 ms. Thus, the visual task required less effort than the phonological task, dyslexics’ behavioural performance was less good and the brain activation delayed compared to controls. Combined behavioural and ERP results of this study indicated that phonological/semantic processing of the word took place 150 ms after processing of its visual features in controls and possibly later in dyslexics

On the Schoenberg Transformations in Data Analysis: Theory and Illustrations

The class of Schoenberg transformations, embedding Euclidean distances into higher dimensional Euclidean spaces, is presented, and derived from theorems on positive definite and conditionally negative definite matrices. Original results on the arc lengths, angles and curvature of the transformations are proposed, and visualized on artificial data sets by classical multidimensional scaling. A simple distance-based discriminant algorithm illustrates the theory, intimately connected to the Gaussian kernels of Machine Learning

Reading Self-Efficacy Predicts Word Reading But Not Comprehension in Both Girls and Boys

The relationship between cognitive skills and reading has been well-established. However, the role of motivational factors such as self-efficacy in reading progress is less clear. In particular, it is not clear how self-efficacy relates to word level reading versus comprehension, and whether this differs in boys and girls. This study examines the relationship between self-efficacy, word reading and reading comprehension across the range of reading abilities after controlling for reading-related cognitive factors. One hundred and seventy nine children (86 males and 93 females) between 8 and 11 years old completed a self-report measure of reading self-efficacy together with measures of reading comprehension and word reading, working memory, auditory short-term memory, phonological awareness, and vocabulary. Boys and girls showed similar levels of attainment and reading self-efficacy. Reading self-efficacy was associated with word reading, but not with reading comprehension in either boys or girls. It is argued that this may reflect important differences between reading self-efficacy and more general measures of reading motivation and engagement. Reading self-efficacy is an element of reading motivation that is closely associated with a child’s perceived attainments in reading and is less susceptible to the gender differences seen in broader measures

Biogeochemical Interactions and Cycling of Sulfur, Iron, and Carbon in Sulfate-Impacted Riparian Wetlands and Wild Rice Waters

University of Minnesota M.S. thesis. August 2018. Major: Earth Sciences. Advisor: Cara Santelli. 1 computer file (PDF); viii, 124 pages.Sulfide accumulation in the porewater of freshwater aquatic systems has been shown to inhibit the growth of many aquatic macrophytes, including wild rice. While interactions between sulfur (S), carbon (C), and iron (Fe) cycles are recognized, secondary “cryptic” S cycles are much less understood; these cycles favor reduction of sulfate over Fe, contrary to traditional thermodynamic expectations; these “cryptic” cycles have been suggested to occur at Second Creek through models by Ng et al. (2017). Using field observations, hydrologic monitoring, and geochemical analyses, we found that changes in hyporheic flux result in changes in porewater SO42- concentrations. Additionally, we have found that intermediate valence S species may act as primary sinks for excess dissolved sulfide. Our comparison study between a SO42--impacted stream and a less-impacted river demonstrates that the accumulation of porewater sulfide may be suppressed through limited TOC, excess sediment Fe, or through generation of S-intermediates

A study of attitudes held by junior college football coaches in California toward the voluntary inter-conference letter of intent

The study was undertaken to determine the attitudes held by the junior college football coaches in California toward the voluntary inter-conference letter of intent.The head football coaches of the seventy-four junior colleges that participate in football were asked to respond to questions concerning selected attitudes held about the voluntary inter-conference letter of intent.The attitudes selected for the questionnaire were determined by a review of the related literature,a pilot study,inquiry letters, rules governing the recruiter,the present voluntary inter-conference letter of intent format,and personal conferences with football coaches. Each junior collage football coach was mailed a packet of information including an explanatory letter, a copy of the present voluntary inter-conference letter of intent,the questionnaire,and a post-paid self-addressed return envelope.Sixty-seven of the seventy four coaches contacted responded by returning a completed questionnaire.Each response was tabulated and identified with one of four areas of concern.Examination of this data suggested that the respondents were generally dissatisfied with the present letter of intent and felt that a more comprehensive national letter of intent could be developed.On the basis of the findings and within the limitations of this study,the following general conclusions appeared just ified: (1) junior college football coaches in California have recruiting problems that are different from those reported by high school coaches;(2)there appears to be a need for a letter of intent designed specifically for the four year college that will service only the junior college athlete;(3)this letter of intent should include a section that explains the athlete's financial aid;and(4)the letter should be enforced by a national organization such as the National Collegiate Athletic Association.California State University, Northridge. Department of Physical Education.Includes bibliographical references (pages 49-51

Correlation functions for ionic motion from NMR relaxation and electrical conductivity in the glassy fast-ion conductor (Li2S)0.56(SiS2)0.44

The Li7 NMR spin-lattice relaxation and the electrical conductivity in the typical glassy fast-ion conductor (Li2S)0.56(SiS2)0.44 are discussed from models of Li+ionic motion with distributions of activation energies, as well as from stretched-exponential time-correlation functions. The measured correlation times from the two effects differ by two orders of magnitude, and the derived distributions are shifted greatly relative to each other. We relate the great differences to percolation around the high barriers in the distribution. We present a phenomenological theory that yields good quantitative fits to the observed NMR relaxation with a Gaussian distribution, and to the conductivity and related dielectric properties with the continuous-time random-walk model and the same Gaussian truncated at the percolation limit. This correlates the two effects in a simple and effective way; both time-correlation functions can be calculated approximately from the distributions, and even the dc conductivity can be calculated from the NMR results. The present approach is discussed and compared with previously proposed models to explain the anomalies in ac electrical-conductivity and NMR relaxation rates in glassy fast-ion conductors

Reply to ‘‘Comment on ‘Correlation functions for ionic motion from NMR relaxation and electrical conductivity in the glassy fast-ion conductor (Li2S)0.56(SiS2)0.44’ ’’

Hunt’s Comment criticizes our recent article for combining concepts from percolation theory and effective-medium theories to calculate the dc and ac conductivities in ionic conducting glasses. Our approach was an attempt to describe the dc and ac conductivity with input information from our NMR measurements. We used the continuous-time random-walk theory and reasonable assumptions for the glasses which yielded good fits of the dc and ac conductivities at many temperatures

Verbal and non-verbal fluency in adults with developmental dyslexia: Phonological processing or executive control problems?

The executive function of fluency describes the ability to generate items according to specific rules. Production of words beginning with a certain letter (phonemic fluency) is impaired in dyslexia, whilst generation of words belonging to a certain semantic category (semantic fluency) is typically unimpaired. However, in dyslexia, verbal fluency has generally been studied only in terms of overall words produced. Furthermore, performance of adults with dyslexia on non-verbal design fluency tasks has not been explored but would indicate whether deficits could be explained by executive control, rather than phonological processing, difficulties. Phonemic, semantic, and design fluency tasks were presented to adults with dyslexia and without dyslexia, using fine-grained performance measures and controlling for IQ. Hierarchical regressions indicated that dyslexia predicted lower phonemic fluency, but not semantic or design fluency. At the fine-grained level, dyslexia predicted a smaller number of switches between subcategories on phonemic fluency, whilst dyslexia did not predict the size of phonemically-related clusters of items. Overall, the results suggested that phonological processing problems were at the root of dyslexia-related fluency deficits; however, executive control difficulties could not be completely ruled out as an alternative explanation. Developments in research methodology, equating executive demands across fluency tasks, may resolve this issue

Relaxation and fluctuations in glassy fast-ion conductors: Wide-frequency-range NMR and conductivity measurements

Li7 nuclear spin-lattice relaxation rates (R1) versus the temperature at several resonance frequencies (4 to 40 MHz) are reported together with the conductivity measurements, σ(ω), in the range 1 Hz to 3.76 MHz on 0.56Li2S+0.44Si2S, a glassy fast-ionic conductor. Both R1 and σ(ω) are fitted consistently over the whole temperature and frequency range by using a stretched-exponential, i.e., exp(-t/τ*c)β for the corresponding correlation functions (CF). Formulas that relate R1(ω) and σ(ω) and that give the asymptotic behavior as functions of T and ω of both quantities are tested experimentally. We find significant differences between βσrelated to σ(ω) and βR related to R1, which implies a difference in the corresponding correlation functions of the ionic diffusional motion. An apparent order-of-magnitude difference in τ*0 attempt times was derived from these conductivity and NMR measurements. The implications of these findings are discussed in terms of the microscopic mechanisms which lead to fluctuations and relaxation in fast-ionic conductors