Home About us Contact
|
Home About us Contact | ||
|
|
||
Processing Capacity (processing + capacity)
Selected AbstractsRecognition of Pixelized Chinese Characters Using Simulated Prosthetic VisionARTIFICIAL ORGANS, Issue 3 2007Xinyu Chai Abstract:, The rehabilitation of the reading ability of the blind with a limited number of stimulating electrodes is regarded as one of the major functions of the envisioned visual prosthesis. This article systematically studied how many pixels of individual Chinese characters should be needed for correct and economic recognition by blind Chinese subjects. In this study, 40 normal-sighted subjects were tested on a self-developed platform HanziConvertor (Institute for Laser Medicine & Bio-photonics, Shanghai Jiaotong University, China) with digital imaging processing capacities to convert images of printed text into various pixelized patterns made up of discrete dots, and present them orderly on a computer screen. It was found that various complicated factors such as pixel number, character typeface, stroke number, etc., can obviously affect the recognition accuracy. It was also found that optimal recognition accuracy occurs at a specific size of binary pixel array, due to a trade-off between a strictly limited number of stimulation electrodes and character sampling resolution. The results showed that (i) recognition accuracy of pixelized characters is optimal with at least 12 × 12 binary pixels, and therefore it is recommended to apply a minimum of 150 discrete and functioning electrodes for restoring the reading ability of blind Chinese individuals in the visual prosthesis; (ii) fonts of Song Ti and Hei Ti are clearer and more effective than other typefaces; and (iii) characters with fewer strokes lead to better accuracy. [source] Dichotic listening and school performance in dyslexiaDYSLEXIA, Issue 1 2008Turid Helland Abstract This study focused on the relationship between school performance and performance on a dichotic listening (DL) task in dyslexic children. Dyslexia is associated with impaired phonological processing, related to functions in the left temporal lobe. DL is a frequently used task to assess functions of the left temporal lobe. Due to the predominance of the contralateral neuronal pathways, a right ear advantage in the DL task reflects the superior processing capacity for the right ear stimulus in the left hemisphere (Kimura, 1963). Previous studies using DL in dyslexia are, however, inconclusive, and may reflect degree of severity of dyslexia. The aim of the present study was therefore to investigate lateralized processing in two sub-groups of dyslexia, differing in symptom severity. Two groups of dyslexic 12-year-old children and an age-matched control group were tested with a consonant,vowel DL task. The two dyslexia groups differed in severity through how they responded to training efforts being made in their schools, while otherwise being matched for age, IQ and diagnosis. The D1 (respondent group) group showed a DL performance pattern similar to the control group, i.e. a right ear advantage, while the D2 (non-respondent) group failed to show a right ear advantage on the DL task. The performance on the DL task by the two dyslexia groups may provide better insight as to the degree of reading and writing impairment in dyslexia. ,Cracking the code' and acquiring automatized literacy skills may seem harder for the D2 group children compared to the D1 children. Also, the present study points to the use of DL as a valid assessment tool in clinical work to improve differential diagnoses, particularly in relation to measures of school performance. Copyright © 2007 John Wiley & Sons, Ltd. [source] Regionalisation of chemical variability in European mountain lakesFRESHWATER BIOLOGY, Issue 12 2009LLUÍS CAMARERO Summary 1. We carried out a coordinated survey of mountain lakes covering the main ranges across Europe (including Greenland), sampling 379 lakes above the local tree line in 2000. The objectives were to identify the main sources of chemical variability in mountain lakes, define a chemical classification of lakes, and develop tools to extrapolate our results to regional lake populations through an empirical regionalisation or upscaling of chemical properties. 2. We investigated the main causes of chemical variability using factor analysis (FA) and empirical relationships between chemistry and several environmental variables. Weathering, sea salt inputs, atmospheric deposition of N and S, and biological activity in soils of the catchment were identified as the major drivers of lake chemistry. 3. We tested discriminant analysis (DA) to predict the lake chemistry. It was possible to use the lithology of the catchments to predict the range of Ca2+ and SO42, into which a lake of unknown chemistry will decrease. Lakes with lower SO42, concentrations have little geologically derived S, and better reflect the variations in atmospheric S loading. The influence of marine aerosols on lakewater chemistry could also be predicted from the minimum distance to the sea and altitude of the lakes. 4. The most remarkable result of FA was to reveal a factor correlated to DOC (positively) and NO3, (negatively). This inverse relationship might be the result either of independent processes active in the catchment soils and acting in an opposite sense, or a direct interaction, e.g. limitation of denitrification by DOC availability. Such a relationship has been reported in the recent literature in many sites and at all scales, appearing to be a global pattern that could reflect the link between the C and N cycles. 5. The concentration of NO3, is determined by both atmospheric N deposition and the processing capacity of the catchments (i.e. N uptake by plants and soil microbes). The fraction of the variability in NO3, because of atmospheric deposition is captured by an independent factor in the FA. This is the only factor showing a clear pattern when mapped over Europe, indicating lower N deposition in the northernmost areas. 6. A classification has been derived which takes into account all the major chemical features of the mountain lakes in Europe. FA provided the criteria to establish the most important factors influencing lake water chemistry, define classes within them, and classify the surveyed lakes into each class. DA can be used as a tool to scale up the classification to unsurveyed lakes, regarding sensitivity to acidification, marine influence and sources of S. [source] Tanzania's coffee sector: constraints and challengesJOURNAL OF INTERNATIONAL DEVELOPMENT, Issue 1 2005John Baffes During the early 1990s, Tanzania embarked in a major reform programme at both macro and sectoral levels. Reforms in agriculture figured prominently, especially in the export crop sectors which during the 1990s accounted for almost two thirds of total merchandize exports. This paper surveys the policy reforms and their impact on the coffee sector, Tanzania's largest export crop. By most accounts, the outcome of reforms has been mixed. While producers' share of export prices increased, official statistics show no supply response. Coffee processing capacity, marketing efficiency, and investment in new plantings increased. Despite the reforms, several issues must are still outstanding. Taxes should be consolidated, lowered, and rationalized. Licensing procedures need to be re-examined. The coffee auction should be voluntary so the costs of vertically integrated exporters will be reduced and cross-border trade will be enhanced. The power of the board and the relevant ministries ought to be substantially reduced and their respective roles clearly defined. Copyright © 2005 John Wiley & Sons, Ltd. [source] The neuropathogenic contributions of lysosomal dysfunctionJOURNAL OF NEUROCHEMISTRY, Issue 3 2002Ben A. Bahr Abstract Multiple lines of evidence implicate lysosomes in a variety of pathogenic events that produce neurodegeneration. Genetic mutations that cause specific enzyme deficiencies account for more than 40 lysosomal storage disorders. These mostly pre-adult diseases are associated with abnormal brain development and mental retardation. Such disorders are characterized by intracellular deposition and protein aggregation, events also found in age-related neurodegenerative diseases including (i) Alzheimer's disease and related tauopathies (ii) Lewy body disorders and synucleinopathies such as Parkinson's disease, and (iii) Huntington's disease and other polyglutamine expansion disorders. Of particular interest for this review is evidence that alterations to the lysosomal system contribute to protein deposits associated with different types of age-related neurodegeneration. Lysosomes are in fact highly susceptible to free radical oxidative stress in the aging brain, leading to the gradual loss of their processing capacity over the lifespan of an individual. Several studies point to this lysosomal disturbance as being involved in amyloidogenic processing, formation of paired helical filaments, and the aggregation of ,-synuclein and mutant huntingtin proteins. Most notably, experimentally induced lysosomal dysfunction, both in vitro and in vivo, recapitulates important pathological features of age-related diseases including the link between protein deposition and synaptic loss. [source] Environment,Flexibility Coalignment and Performance: An Analysis in Large versus Small FirmsJOURNAL OF SMALL BUSINESS MANAGEMENT, Issue 3 2006Antonio J. Verdú-Jover This paper takes a wide-ranging transnational look, within the frame of he European Union, at the differences between large and small firms based on practices of flexibility. More specifically, the research aims to evaluate whether small firms form a homogeneous body in applying flexible practices as opposed to large firms, as well as observing the differential effects on performance when there are discrepancies in the coalignment levels between a firm's actual flexibility and that required by the environment. The hypotheses are tested using data from 417 European firms. The results reveal that (1) good coalignments between actual and required flexibility (flexibility fit) have a greater influence on business performance in the case of small firms; (2) there are significant differences between small and large firms as regards operative flexibility, strategic flexibility, financial flexibility (organizational slack), and performance. The large firms analyzed coalign their flexibility fit better in their various dimensions (structural, operative, and strategic); (3) the degree of metaflexibility can be greater among small firms, which represents a greater information processing capacity, thus enabling the flexibility fit to be constantly coaligned to changes in the environment. However, a greater metaflexibility is not immediately reflected in the flexibility fit; and (4) this greater flexibility fit among large firms can be favored by their greater financial flexibility. [source] INTEGRATED MANAGEMENT OF IN-FIELD, EDGE-OF-FIELD, AND AFTER-FIELD BUFFERS,JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2006Seth M. Dabney ABSTRACT: This review summarizes how conservation benefits are maximized when in-field and edge-of-field buffers are integrated with each other and with other conservation practices such as residue management and grade control structures. Buffers improve both surface and subsurface water quality. Soils under permanent buffer vegetation generally have higher organic carbon concentrations, higher infiltration capacities, and more active microbial populations than similar soils under annual cropping. Sediment can be trapped with rather narrow buffers, but extensive buffers are better at transforming dissolved pollutants. Buffers improve surface runoff water quality most efficiently when flows through them are slow, shallow, and diffuse. Vegetative barriers - narrow strips of dense, erect grass - can slow and spread concentrated runoff. Subsurface processing is best on shallow soils that provide increased hydrologic contact between the ground water plume and buffer vegetation. Vegetated ditches and constructed wetlands can act as "after-field" conservation buffers, processing pollutants that escape from fields. For these buffers to function efficiently, it is critical that in-field and edge-of-field practices limit peak runoff rate and sediment yield in order to maximize contact time with buffer vegetation and minimize the need for cleanout excavation that destroys vegetation and its processing capacity. [source] Exploring the Relationship Between Modified Output and Working Memory CapacityLANGUAGE LEARNING, Issue 3 2010Alison Mackey This study examines the relationship between learners' production of modified output and their working memory (WM) capacity. The task-based interactions of 42 college-level, native English-speaking learners of Spanish as a foreign language were examined. A relationship was found between learners' WM test scores and their tendency to modify output. Specifically, greater processing capacity was related to greater production of modified output during interaction. [source] TIMBER MARKETS AND FUEL TREATMENTS IN THE WESTERN U.S.NATURAL RESOURCE MODELING, Issue 1 2006KAREN L. ABT ABSTRACT. We developed a model of interrelated timber markets in the U.S. West to assess the impacts of large-scale fuel reduction programs on these markets, and concomitant effects ofthe market on the fuel reduction programs. The linear programming spatial equilibrium model allows interstate and international trade with western Canada and the rest of the world, while accounting for price effects of introducing softwood logs to the market. The model maximizes area treated, given fire regime-condition class priorities, maximum increases in softwood processing capacity, maximum rates of annual treatments, prohibitions on exports of U.S. and Canadian softwood logs from public lands and a fixed annual treatment budget. Results show that the loss to U.S. private timber producers is less than the gains for timber consumers (mills). States receiving more treatments when spending is not constrained by state proportions include Idaho, Montana, New Mexico and Oregon. When only the wildland-urban interface is treated, California, Oregon and Washington receive more treatments. Utah and Colorado receive more treatments when low risk stands are included. [source] The n -back as a dual-task: P300 morphology under divided attentionPSYCHOPHYSIOLOGY, Issue 6 2001Scott Watter The n -back task was hypothesized to be a dual task, permitting the imposition of parametrically increasing attentional and working memory demands, while keeping constant the demands of an embedded matching subtask. Visual targets were presented for 200 ms every 2.2 s at pseudorandomly varying positions on a computer screen. Participants were required to remember the most recent 0, 1, 2, or 3 positions and responded with a choice button push to whether the current target position matched the position presented n items previously. P300 peak latency was constant across n -back tasks, reflecting constant perceptual and cognitive demands of the matching subtask. P300 peak amplitude decreased with increasing memory load, reflecting reallocation of attention and processing capacity away from the matching subtask to working memory activity. These data support a dual-task nature of the n -back, which should be considered when employing this paradigm. [source] Processing Limitations in Children With Specific Language Impairment: The Role of Executive FunctionCHILD DEVELOPMENT, Issue 6 2006Nancie Im-Bolter Research suggests that children with specific language impairment (SLI) have processing limitations; however, the mechanisms involved have not been well defined or investigated in a theory-guided manner. The theory of constructive operators was used as a framework to explore processes underlying limited processing capacity in children with SLI. Mental attentional capacity, mental attentional interruption, and 2 specific executive functions (shifting and updating) were examined in 45 children with SLI and 45 children with normally developing language, aged 7 to 12 years. The results revealed overall group differences in performance on measures of mental attention, interruption, and updating, but not shifting. The findings supported the premise that mental attention predicted language competence, but that this relationship was mediated partially by updating. [source] | ||||||||||||||||