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How do readers know where to look next? Local information distributions influence eye fixations.

Skilled readers' eye movements were recorded as they inspected sentences in preparation for comprehension questions. The sentences were written around target words that had uneven distributions of information, in that the words were predictable, given either the first few letters or the last few letters. Some parts of these words can be described as being more important than others for successful word recognition, and the experiments asked whether inspection patterns reflect the uneven distributions. Four types of ten-letter word were used: words with highly redundant endings (e.g. engagement), with moderately redundant endings (e.g. repatriate), with moderately redundant beginnings (e.g. superstore), and words with informative beginnings and endings (e.g. amalgamate). Redundancy was defined operationally in terms of the number of possible completions of a word given the first few or last few letters. A highly redundant ending is therefore one that occurs frequently and cannot be used to identify the word. Words gaining just one fixation received this fixation nearer to the word's centre than in the case of the first fixation upon words gaining two fixations. The single fixation also had a longer duration, giving support to the notion of a convenient viewing location, which, when achieved, can lead to a net saving in inspection time. In the case of words with redundant endings gaining just one fixation, the fixation was nearer to the beginning of the word than in the case of words with informative endings, and this influence of word type upon the location of the first fixation was interpreted in favour of the parafoveal processing hypothesis of eye guidance during reading.

Adult

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

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

AIDS in California family medicine. Changing experiences, knowledge, and geographic distribution.

Information regarding practice patterns specific to acquired immunodeficiency syndrome (AIDS) was obtained in 1988 from 1774 family physicians in California using a mail survey. Data were analyzed across the following county groupings: Los Angeles County, other counties in standard metropolitan statistical areas, and counties outside standard metropolitan statistical areas. Comparisons were made with the data from a telephone survey conducted in 1986. Differences over time were analyzed. By 1988, the percentage of physicians treating or referring patients for possible AIDS had more than doubled in counties outside standard metropolitan statistical areas. The percentage of physicians reporting one or more diagnosed cases of AIDS had tripled, a finding that suggests the importance of AIDS in family medicine is increasing at a rapid rate. In addition, survey results indicate that a majority of those surveyed still lack the AIDS-related knowledge and competency necessary to effectively deal with AIDS.

Acquired Immunodeficiency Syndrome

The temporal distribution of stimulus information in the visual evoked potential.

Research in psychophysics (Bloch's law) and perceptual experiments concerned with the integration of successively presented stimuli suggest that the perception of form is a process that occurs over a period of as much as 200-300 msec. Such results prompted the question of whether the visual evoked potential (VEP) might contain information about the distribution over time of perceptual processing. Subjects viewed lines formed from combinations of three lengths and four angles while the EEG was recorded. Analysis of the VEPs indicated that the length and angle of the lines produced temporal distributions of information in the VEP and that the distributions for length and angle were somewhat different. The major difference was that the processing of angle begins earlier and is completed sooner than the processing of length. A conclusion of the experiment was that an alternative or supplement to analyzing VEPs for specific waveform features is to consider the encoding of stimulus information in the VEP as a density or concentration over time.

Adult

How does flow cytometry express Gaussian distributed biological information?

The analogue-to-digital conversion step in flow cytometric analysis introduces a positive skew into the distribution of any measured parameter. In this communication we describe a semi-analytical method to determine if a distribution skewed by the analogue-to-digital conversion step is compatible with a Gaussian origin. The procedure involves determining the errors associated with calculating the coefficient of variation from the skewed distribution and applying systematic corrections. The method was tested with a number of experimental data sets and is illustrated with 3 distributions. One of these was not compatible with a Gaussian origin, but the other 2 were, in spite of considerable positive skewness in the data.

Blood Cell Count

Overview of an architectural approach to the development of the Johns Hopkins Hospital distributed clinical information system.

The Johns Hopkins Hospital has initiated an ambitious program to apply modern technologies to the development of a new, comprehensive clinical information system. Since many components of a system exist and since the JHH management is decentralized, a distributed, networked system is being built. To properly accomplish this task an architectural basis for strategic systems planning was developed. This paper reviews briefly the layered architectural approach.

Computer Communication Networks

The value of questionnaires aimed at key informants, and distributed through an existing administrative system, for rapid and cost-effective health assessment.

The requirement for a careful interview set-up in the classical key-informant approach considerably limits its extension to a larger scale. However, the administration of simplified questionnaires entirely through an existing administrative system can provide an alternative approach and become a valuable tool for fast and cost-efficient community health assessment. This methodology relies on a well-structured and working administrative system, and is restricted to health problems that are well and distinctly perceived by community members. It gives mainly qualitative results, and can therefore be used to single out rapidly and inexpensively high-risk and low-risk units. The biomedical screening of a large number of negative units can thus be avoided, and available resources can be concentrated on the positive ones. An extensive validation of this "indirect" approach by standardized biomedical measurements is a crucial requirement for its usefulness. In addition to biomedical information, questionnaires also provide information on the perception and prioritization of community health problems, which is of interest for health planning.

Child

Gene regulatory network structure informs the distribution of perturbation effects.

Gene regulatory networks (GRNs) govern many core developmental and biological processes underlying human complex traits. Even with broad-scale efforts to characterize the effects of molecular perturbations and interpret gene coexpression, it remains challenging to infer the architecture of gene regulation in a precise and efficient manner. Key properties of GRNs, like hierarchical structure, modular organization, and sparsity, provide both challenges and opportunities for this objective. Here, we seek to better understand properties of GRNs using a new approach to simulate their structure and model their function. We produce realistic network structures with a novel generating algorithm based on insights from small-world network theory, and we model gene expression regulation using stochastic differential equations formulated to accommodate modeling molecular perturbations. With these tools, we systematically describe the effects of gene knockouts within and across GRNs, finding a subset of networks that recapitulate features of a recent genome-scale perturbation study. With deeper analysis of these exemplar networks, we consider future avenues to map the architecture of gene expression regulation using data from cells in perturbed and unperturbed states, finding that while perturbation data are critical to discover specific regulatory interactions, data from unperturbed cells may be sufficient to reveal regulatory programs.

Gene Regulatory Networks

[The information value of the clinical data related to the vital prognosis in severe combined trauma].

Data are reported on a study of the informative value of ten clinical and laboratory parameters, which have a bearing on the vital prognosis of severe combined trauma. The presentation is part of a more comprehensive study, aimed at creating an expert system for prognosticating this type of pathology. Case material from the Clinic of Anesthesiology, Resuscitation and Intensive Treatment at the "Pirogov" Emergency Hospital in Sofia was used (1986-1988). Included in the study were 455 patients with severe combined traumatic injuries, of whom 210 died and 245 survived. The following methods were used for quantitative assessment of the informative value: for determining the descriptive informative value--informative criterion by Mel'nikov and informative criterion by Bykhovskiĭ [correction of Bihovski]; for the distributing informative value--the method of Kulback and modification of this method, as described by Genkin-Gubler. Simultaneous use of all four methods allowed to precise the values being obtained and to perform with maximal exactness the intervals relevant to the prognosis. This furnished the opportunity to distribute the individual parameters in highly informative groups, designated for entrance to the projected expert system.

Acute Disease

Morphological evidence for parallel processing of information in rat macula.

Study of montages, tracings and reconstructions prepared from a series of 570 consecutive ultrathin sections shows that rat maculas are morphologically organized for parallel processing of linear acceleratory information. Type II cells of one terminal field distribute information to neighboring terminals as well. The findings are examined in light of physiological data which indicate that macular receptor fields have a preferred directional vector, and are interpreted by analogy to a computer technology known as an information network.

Acoustic Maculae

[Prediction of postoperative pulmonary function in the patient undergoing pneumonectomy using combined pulmonary function test and ventilation/perfusion scintiphotography].

A method to predict postoperative lung function following pneumonectomy has been used in 11 patients. Preoperative unilateral lung function can be predicted by combining the preoperative information on lung volumes obtained by spirometry with the distributional information obtained from ventilation and perfusion scintigrams in order to estimate lung function after pneumonectomy. There was a high degree of correlation between predicted and measured lung function for both FEV1 (r = 0.81, p less than 0.050, and FVC (r = 0.81, p less than 0.05). The postoperative FEV1 and FVC were within 200 ml of the predicted value in most of the patients. A more accurate and easy prediction of postoperative lung function is obtained using unilateral perfusion rather than ventilation scintigrams. We suggest that the combined the results of simple spirometric data and a quantitative right-vs-left perfusion lung scan using radioactive Tc-99m provides a simple non-invasive and accurate method for the pre-operative functional evaluation of the high risk patient.

Adult

Toward an analysis of conscious activity: 2. The functions of sleep and wakefulness.

What we generally call information is created through interference between regular information and reverse information. In this process, conscious activity is the creator of information. We can assume that the following five-stage mechanism exists inside the brain: 1) a mechanism that creates consciousness and recognizes information; 2) a mechanism that accumulates information in the neural circuits; 3) a mechanism that combines and separates the self-conscious mind and fragments of accumulated information; 4) a mechanism that accesses the operating system or distributes information to localized neural circuits; and 5) a mechanism that allows the operating system to modify itself with an increase in the amount of information. These mechanisms can be considered to belong to the category of conscious activity, which is created by a combination of potentialization of sleep and potentialization of wakefulness.

Brain