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Infant sensitivity to distributional information can affect phonetic discrimination.

For nearly two decades it has been known that infants' perception of speech sounds is affected by native language input during the first year of life. However, definitive evidence of a mechanism to explain these developmental changes in speech perception has remained elusive. The present study provides the first evidence for such a mechanism, showing that the statistical distribution of phonetic variation in the speech signal influences whether 6- and 8-month-old infants discriminate a pair of speech sounds. We familiarized infants with speech sounds from a phonetic continuum, exhibiting either a bimodal or unimodal frequency distribution. During the test phase, only infants in the bimodal condition discriminated tokens from the endpoints of the continuum. These results demonstrate that infants are sensitive to the statistical distribution of speech sounds in the input language, and that this sensitivity influences speech perception.

Attention↗

Rethinking the word frequency effect: the neglected role of distributional information in lexical processing.

Attempts to quantify lexical variation have produced a large number of theoretical and empirical constructs, such as Word Frequency, Concreteness, and Ambiguity, which have been claimed to predict between-word differences in lexical processing behavior. Models of word recognition that have been developed to account for the effects of these variables have typically lacked adequate semantic representations, and have dealt with words as if they exist in isolation from their environment. We present a new dimension of lexical variation that is addressed to this concern. Contextual Distinctiveness (CD), a corpus-derived summary measure of the frequency distribution of the contexts in which a word occurs, is naturally compatible with contextual theories of semantic representation and meaning. Experiment 1 demonstrates that CD is a significantly better predictor of lexical decision latencies than occurrence frequency, suggesting that CD is the more psychologically relevant variable. We additionally explore the relationship between CD and six subjectively-defined measures: Concreteness, Context Availability, Number of Contexts, Ambiguity, Age of Acquisition and Familiarity and find CD to be reliably related to Ambiguity only. We argue for the priority of immediate context in determining the representation and processing of language.

Databases, Factual↗

Teledermatology in a capitated delivery system using distributed information architecture: design and development.

OBJECTIVE: This report describes the design, development, and technical evaluation of a teledermatology system utilizing digital images and electronic forms captured through, stored on, and viewed through a common web server in an urban capitated delivery system. MATERIALS AND METHODS: The authors designed a system whereby a primary care physician was able to seek a dermatologic consultation electronically, provide the specialist with digital images acquired according to a standardized protocol, and review the specialist response within 2 business days of the request. The settings were two primary care practices in eastern Massachusetts that were affiliated with a large integrated delivery system. Technical evaluation of the effectiveness of the system involved 18 patients. Main outcome measures included physician and patient satisfaction and comfort and efficiency of care delivery. RESULTS: In 15 cases, the consultant dermatologist was comfortable in providing definitive diagnosis and treatment recommendations. In 3 cases, additional information (laboratory studies or more history) was requested. There were no instances where the dermatologist felt that a face-to-face visit was necessary. CONCLUSIONS: This novel approach shows promise for the delivery of specialist expertise via the internet. Cost-effectiveness studies may be necessary for more widespread implementation.

Computer Systems↗

Durable data. A rehabilitation center collects and distributes information for functional assessment and program evaluation.

As physical rehabilitation services have expanded nationwide, both payers and providers have increasingly felt the need for adequate outcome data. In 1988 organizers at Marianjoy Rehabilitation Center, Wheaton, IL, launched the Center for Rehabilitation Outcome Analysis-a service for rehabilitation facilities that want to develop in-house functional assessment and program evaluation systems. The center has focused on meeting three major needs of rehabilitation providers: outcome data analysis and reporting, education, and research. It uses the Patient Evaluation and Conference System for a variety of needs from planning programs to establishing functional outcome expectations. The center also educates participants on the use and meaning of outcome data. In addition, it has enlisted the help of the profession's behavioral scientists, evaluators, and statisticians to scrutinize and enhance program evaluation and measurement models.

Activities of Daily Living↗

PlasmID: a centralized repository for plasmid clone information and distribution.

The Plasmid Information Database (PlasmID; http://plasmid.hms.harvard.edu) was developed as a community-based resource portal to facilitate search and request of plasmid clones shared with the Dana-Farber/Harvard Cancer Center (DF/HCC) DNA Resource Core. PlasmID serves as a central data repository and enables researchers to search the collection online using common gene names and identifiers, keywords, vector features, author names and PubMed IDs. As of October 2006, the repository contains >46 000 plasmids in 98 different vectors, including cloned cDNA and genomic fragments from 26 different species. Moreover, the clones include plasmid vectors useful for routine and cutting-edge techniques; functionally related sets of human cDNA clones; and genome-scale gene collections for Saccharomyces cerevisiae, Pseudomonas aeruginosa, Yersinia pestis, Francisella tularensis, Bacillus anthracis and Vibrio cholerae. Information about the plasmids has been fully annotated in adherence with a high-quality standard, and clone samples are stored as glycerol stocks in a state-of-the-art automated -80 degrees C freezer storage system. Clone replication and distribution is highly automated to minimize human error. Infor-mation about vectors and plasmid clones, including downloadable maps and sequence data, is freely available online. Researchers interested in requesting clone samples or sharing their own plasmids with the repository can visit the PlasmID website for more information.

Biological Specimen Banks↗

Communication services for a distributed hospital information system.

Planning principles and development are described of a communication server which controls and performs all information exchange between distributed and heterogeneous applications in a hospital information system. The analysis is based on business process modeling. At present, the core of the server uses a commercial product (Cloverleaf). This allows to connect both old systems with no or few interface features and new systems with modern interface facilities (such as HL7). Prerequisites, functions, and configuration of the server software are described in detail. Experiences, advantages, and disadvantages are discussed.

Communication↗

Transaction processing using remote procedure calls (RPC) for a heterogeneous distributed clinical information system.

The Johns Hopkins Hospital is developing a distributed clinical information system that integrates functionally several UNIX, IBM MVS/CICS and MUMPS computer systems. Distributed application development is accomplished by interprocess communications across Ethernet using remote procedure calls. The remote procedure call (RPC) protocol provides a standard approach to the development of distributed applications using the metaphor of a subroutine call. The Sun Microsystems RPC and XDR (external data representation) protocols have been implemented in these environments. The systems, the distributed model, RPC implementations and applications examples are discussed.

Computer Communication Networks↗

A meta-analysis of estimates of the AIDS incubation distribution.

Information from 12 studies is combined to estimate the AIDS incubation distribution with greater precision than is possible from a single study. The analysis uses a hierarchy of parametric models based on a four-parameter generalized F distribution. This general model contains four standard two-parameter distributions as special cases. The cases are the Weibull, gamma, log-logistic, lognormal distributions. These four special cases subsume three distinct asymptotic hazard behaviors. As time increases beyond the median of approximately 10 years, the hazard can increase to infinity (Weibull), can plateau at some constant level (gamma), or can decrease to zero (log-logistic and lognormal). The Weibull, gamma and 'log-logistic distributions' which represent the three distinct asymptotic hazard behaviors, all fit the data as well as the generalized F distribution at the 25 percent significance level. Hence, we conclude that incubation data is still too limited to ascertain the specific hazard assumption that should be utilized in studies of the AIDS epidemic. Accordingly, efforts to model the AIDS epidemic (e.g., back-calculation approaches) should allow the incubation distribution to take several forms to adequately represent HIV estimation uncertainty. It is recommended that, at a minimum, the specific Weibull, gamma and log-logistic distributions estimated in this meta-analysis should all be used in modeling the AIDS epidemic, to reflect this uncertainty.

Acquired Immunodeficiency Syndrome↗

Distinctions between manipulation and function knowledge of objects: evidence from functional magnetic resonance imaging.

A prominent account of conceptual knowledge proposes that information is distributed over visual, tactile, auditory, motor and verbal-declarative attribute domains to the degree to which these features were activated when the knowledge was acquired [D.A. Allport, Distributed memory, modular subsystems and dysphagia, In: S.K. Newman, R. Epstein (Eds.), Current perspectives in dysphagia, Churchill Livingstone, Edinburgh, 1985, pp. 32-60]. A corollary is that when drawing upon this knowledge (e.g., to answer questions), particular aspects of this distributed information is re-activated as a function of the requirements of the task at hand [L.J. Buxbaum, E.M. Saffran, Knowledge of object manipulation and object function: dissociations in apraxic and non-apraxic subjects. Brain and Language, 82 (2002) 179-199; L.J. Buxbaum, T. Veramonti, M.F. Schwartz, Function and manipulation tool knowledge in apraxia: knowing 'what for' but not 'how', Neurocase, 6 (2000) 83-97; W. Simmons, L. Barsalou, The similarity-in-topography principle: Reconciling theories of conceptual deficits, Cognitive Neuropsychology, 20 (2003) 451-486]. This account predicts that answering questions about object manipulation should activate brain regions previously identified as components of the distributed sensory-motor system involved in object use, whereas answering questions about object function (that is, the purpose that it serves) should activate regions identified as components of the systems supporting verbal-declarative features. These predictions were tested in a functional magnetic resonance imaging (fMRI) study in which 15 participants viewed picture or word pairs denoting manipulable objects and determined whether the objects are manipulated similarly (M condition) or serve the same function (F condition). Significantly greater and more extensive activations in the left inferior parietal lobe bordering the intraparietal sulcus were seen in the M condition with pictures and, to a lesser degree, words. These findings are consistent with the known role of this region in skilled object use [K.M. Heilman, L.J. Gonzalez Rothi, Apraxia, In: K.M. Heilman, E. Valenstein (Eds.), Clinical Neuropsychology, Oxford University Press, New York, 1993, pp. 141-150] as well as previous fMRI results [M. Kellenbach, M. Brett, K. Patterson, Actions speak louder than functions: the importance of manipulability and action in tool representation, Journal of Cognitive Neuroscience, 15 (2003) 30-46] and behavioral findings in brain-lesion patients [L.J. Buxbaum, E.M. Saffran, Knowledge of object manipulation and object function: dissociations in apraxic and non-apraxic subjects, Brain and Language, 82 (2002) 179-199]. No brain regions were significantly more activated in the F than M condition. These data suggest that brain regions specialized for sensory-motor function are a critical component of distributed representations of manipulable objects.

Adult↗

Inspecting asymmetric presentations of words differing in informational and morphemic structure.

Are laterality effects in visual word recognition a product of functional asymmetry of the cerebral hemispheres or a result of stimulus inspection factors such as asymmetric eye fixations before and during visual presentation, different movement time to asymmetric targets, an interaction of the informative components, or morphemic structure of a target with a drop in acuity with distance? Two experiments were conducted to address these questions. Experiment One recorded the inspection of prefixed and matched control words presented unilaterally for 200 msec. Experiment Two displayed suffixed words and their appropriate controls. The words also varied in their information distribution. Reader's eye movements were monitored while they inspected the target words in preparation for a synonym judgement task. Measures of the location of the initial fixation on the screen showed that subjects were not biased to the right visual field prior to stimulus onset. When only those occasions in which the subject had correctly fixated the central cursor were analyzed, a robust right visual field advantage was observed on many of the target inspection time measures, but no reliable difference was observed for faster movement time to the right visual field's target compared to that observed in the left visual field. Neither the distribution of information within the word nor its morphemic structure affected the pattern of any inspection time measures. Consequently, such factors can be ruled out as threats to the hypothesis concerned with the functional asymmetry of the cerebral hemispheres.

Acoustic Stimulation↗

Geo-referenced multimedia environmental fate model (G-CIEMS): model formulation and comparison to the generic model and monitoring approaches.

A spatially resolved and geo-referenced dynamic multimedia environmental fate model, G-CIEMS (Grid-Catchment Integrated Environmental Modeling System) was developed on a geographical information system (GIS). The case study for Japan based on the air grid cells of 5 x 5 km resolution and catchments with an average area of 9.3 km2, which corresponds to about 40,000 air grid cells and 38,000 river segments/catchment polygons, were performed for dioxins, benzene, 1,3-butadiene, and di-(2-ethyhexyl)phthalate. The averaged concentration of the model and monitoring output were within a factor of 2-3 for all the media. Outputs from G-CIEMS and the generic model were essentially comparable when identical parameters were employed, whereas the G-CIEMS model gave explicit information of distribution of chemicals in the environment. Exposure-weighted averaged concentrations (EWAC) in air were calculated to estimate the exposure ofthe population, based on the results of generic, G-CIEMS, and monitoring approaches. The G-CIEMS approach showed significantly better agreement with the monitoring-derived EWAC than the generic model approach. Implication for the use of a geo-referenced modeling approach in the risk assessment scheme is discussed as a generic-spatial approach, which can be used to provide more accurate exposure estimation with distribution information, using generally available data sources for a wide range of chemicals.

Benzene↗

Eye fixations are influenced by the distribution of information within words.

Reader's eye movements were monitored while they inspected isolated words in preparation for a synonym judgement task. The 10-letter words appeared on a screen near the point of fixation, with the first fixation being imposed near the beginning, or the centre, or the ending of the word. The words themselves had uneven distributions of information, in that the beginnings or the endings contained common sequences of letters in English. Three types of words were used: those with very redundant endings (e.g., yearningly), with moderately redundant endings (e.g., varnishing), and with moderately redundant beginnings (e.g., contravene). Redundancy was defined in terms of the total number of words in English which possess that particular sequence of five letters as the beginning or the ending. The experiments asked whether the convenient viewing location within a word varied according to the distribution of information, and whether the extent of redundancy in a word ending is reflected in the distribution of visual attention given to the word. The results were analysed separately for those cases where the reader made just two fixations upon the word before moving to the synonym task, and for those cases where the reader made exactly three fixations. These were the dominant fixation patterns. Evidence for the notion of a convenient viewing position consisted of long first fixations (when there were just two fixations), when this fixation was near the centre of the word. The distribution of information within the words did not influence the duration of the first fixation, although the duration of the gaze within each half-word did increase when more informative letter sequences were being inspected. The extent of redundancy was also seen to influence the inspection patterns, when a comparison was made between the two types of words with redundant endings. Words with very redundant endings received fewer fixations when the first fixation was at the beginning, and for words gaining exactly two fixations, the second fixation was shorter if the word had a very redundant ending.

Adult↗

The Healthcare Administrator's Associate: an experiment in distributed healthcare information systems.

The Healthcare Administrator's Associate is a collection of portable tools designed to support analysis of data retrieved via the Internet from diverse distributed healthcare information systems by means of the InfoSleuth system of distributed software agents. Development of these tools is part of an effort to enhance access to diverse and geographically distributed healthcare data in order to improve the basis upon which administrative and clinical decisions are made.

Computer Communication Networks↗