PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Natural Language Processing”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,729 records · Page 96Linked to original sources

Evaluation of a computer-aided learning program in removable partial denture framework designing.

Assessment of a computer-assisted learning (CAL) program dealing with designing removable partial dentures was performed as both formative and summative evaluation. Formative evaluation was obtained through open-ended questions in a written questionnaire administered to 60 junior students from two Australian Dental Schools and through observation of four groups of these students as they worked through the program. Formative evaluation, fundamental to completion of the program, led to several changes and additions. Observation of the students using the program during its final stages of development was one of the most informative and helpful parts of the evaluation. It allowed nuances of expression and body language to be noted that would not have been apparent in written or numerical data. Summative evaluation was obtained through structured questions in the questionnaire and through a post-CAL test under examination conditions. Summative assessment showed that students could attain a desired standard of knowledge if a lecture series was replaced by the CAL program; that the program was user-friendly, even for students with little or no computer experience; and that most students considered it to be a useful learning resource. More than half the students were concerned about using CAL to replace human instruction. It is significant that students were particularly impressed by aspects of the program that could not be duplicated by a book; the interactive nature of the learning process and the ability to rotate the diagnostic casts. This highlights the need for CAL programs to use the full potential of computer capability, rather than merely replicate a textbook on a screen.

Computer-Assisted Instruction↗

Development and validation of HEPAR, an expert system for the diagnosis of disorders of the liver and biliary tract.

HEPAR is an expert system in the field of hepatology which can be used as a supportive tool in the diagnosis of disorders of the liver and biliary tract. The representation language employed in HEPAR consists of production rules with object-attribute-value triples. In the system, medical diagnosis is modelled according to the strategy which is clinically used in this field. The patient's disorder is assessed in two stages. In the first stage, available data from medical interview, physical examination and simple laboratory tests are used to determine whether the disorder is hepatocellular or biliary obstructive in nature, and whether benign or malignant features are present. In the second stage the system produces a subset of possible diagnoses out of a set of more than 80 disease categories, using additional data from supplementary tests. The results of the first stage classification cause considerable pruning of the search space. In this paper the structure, development process and approach followed in the validation of the HEPAR system are described. The results of a recent performance validation study using data from 181 consecutive patient cases are discussed.

Biliary Tract Diseases↗

Audiologic aspects of learning and behavior.

To effectively deal with learning and behavioral problems, physicians must acquire a new knowledge base and interact meaningfully with professionals from a variety of disciplines. They must be aware that audiologic factors are only one part of a complex matrix of components contributing to learning and behavior. Although the exact nature of these components is still being defined, their interrelationship can be hypothesized. An individual can overcome the uncertainties and avoid inappropriate diagnoses in this field by applying a comprehensive, descriptive diagnostic process. With a broad understanding of the transactional model of learning and behavior, physicians can ensure that audiologic problems are defined and addressed appropriately. By acknowledging this approach in the identification, assessment and management of children with learning and behavioral dysfunction, the physician can become a powerful advocate for these children.

Child↗

A laser densitometer for selective spot analysis on dot blots and two-dimensional gel autoradiograms.

We describe an inexpensive densitometer, employing a small HeNe laser and an IBM-compatible personal computer that performs accurate measurements of selected spots on two-dimensional gel autoradiograms or chromatograms with an accuracy and a sensitivity equal or superior to those of many commercial instruments. Our open-table design allows the operator to visually monitor the scanning process in room lighting, and provides great flexibility in both the size and the nature of items to be scanned. The instrument has two moving parts (a prism and a small motor). A commercially available software package (ASYST) acquires digital data, graphs the data on the TV monitor, converts the data to optical density or to radioactive incorporation (cpm), subtracts background, integrates peak areas, and stores data on disk. The total time for these operations is 20-30 s per spot. The instrument has a dynamic range of 0.25 to 3.0 OD units and can measure a 10,000-fold range of 14C or 35S isotope concentrations on autoradiograms. The complete device can be assembled with a hobbyist's knowledge of electronics, moderate programming abilities (no machine language required), and a cost of less than $3000, not including the IBM PC.

Costs and Cost Analysis↗

Talking contracts and taking care: managers and professionals in the British National Health Service internal market.

This paper draws on audio-recordings of a Health Authority's contract monitoring meetings with hospital providers to examine the nature of interactions between managers and clinical professionals in the British National Health Service internal market. It describes how managers and professionals arrive at a working division of labour, which acknowledges their respective spheres of expertise, but also leaves a space where definitions are contested. There is an interplay of competing managerial and professional discourses which construct problems and proposed solutions in fundamentally non-commensurable ways. Yet only rarely do managers or professionals mount challenges in ways that bring them on to the territory of the other group; rather each group seeks to frame problems to mesh with its special domain of competence. Managers seek to push back the boundaries of professional control by constructing a language and set of practices which will govern the contracting process. But they remain reliant on professionals to mediate between the requirements of contracting and the realities of clinical work. Clinical arguments continue to have high perceived legitimacy for managers, and will often be taken up by hospital managers in negotiations with their Health Authority counterparts. It is argued that the dependency of managers on professionals to make the contracting system work, taken together with the continued social and cultural authority of senior medical consultants, limits managers' ability to control professionals.

Contract Services↗

Sources of error in constructing and interpreting graphs: a study of fourth- and fifth-grade students with LD.

The purpose of this study was to examine students' understanding of and ability to interpret line graphs, using four tasks: two where students constructed a graph and two where students interpreted a given graph. The tasks were unique in that they did not simply involve the explanation of given data but included a language component that looked at students' cognitive processes and understanding while they were engaged in the tasks. The study is important because students are often able to define and even draw graphs yet perform poorly on graph interpretation items presented in high-stakes examinations. The sample for the study consisted of 91 fourth and fifth graders with and without learning disabilities (LD) from six schools in a major metropolitan area. Scoring rubrics were designed for each item. An analysis of variance by grade and group indicated no significant differences between fourth and fifth graders overall but revealed that typically achieving students performed at significantly higher levels than students with LD at both grade levels. Additional descriptive analyses looked at the patterns of errors evidenced and the nature of the students' constructions. These are discussed, and instructional implications are derived.

Achievement↗

The scientific basis for visible particle inspection.

The following paper was presented at the 1999 PDA International Conference in Tokyo, Japan February 24, 1999. The paper was written in response to the recent well-publicized incidents in Japan in which the presence of visible particulates in injectable products was observed. These incidents should be considered a wake-up call to all concerned with injectable pharmaceutical products. The overview of visible particle inspection presented at the Tokyo PDA Meeting is reprinted here as a reminder that a global marketplace requires well-defined parameters and evaluation methods. In the absence of these basic requirements continuation of the present conflicting particle contamination evaluations will continue by default. At this time, visible particle inspection around the world lacks both direction and an accepted common language. The adoption of the probabalistic concepts introduced by Knapp and co-workers in 1980 can supply these basic requirements. The use of the probabalistic model and the statistically defined particle quality regions defined by Knapp and co-workers in 1980 was, at that time, a concept foreign to pharmaceutical quality. In the period since 1980, the methodology then introduced has been expanded and simplified. The analysis used by these workers was similar to that used in life insurance calculations and is just as reliable. The results obtained following the adoption of the framework and probabalistic concepts introduced by Pflug in sterile products since 1973 supports the use of tested and verified probabalistic concepts in the production of injectable products. Pflug's work has provided a basis for the secure communication of sterile production methods and results. This improvement in communication has potentiated a surge in sterile product improvement and a consequent reduction in product cost. The use of the probabalistic model and statistically defined particle contamination quality regions introduced by Knapp and co-workers in 1980 is believed to have a similar potential to improve product quality and reduce inspection costs in visible particle inspection procedures. Application of the probabalistic model results in a numerical evaluation of both the inspection security achieved in rejecting visible defects and the excess cost introduced by the false reject rate of good product. It has the ability to translate the U.S.P. language "essentially free" of particle contamination into objective, reproducible numerical results. Visible particle contamination data can be successfully analyzed only when its probabalistic nature is understood. The effect of disregarding the probabalistic nature of visible inspection data is well illustrated by the results of the landmark 1940 court case brought by Bristol Labs against the F.D.A. The F.D.A. contention that the containers were contaminated with visible particles was challenged by Bristol in a court case. When the experienced inspector, who reported the contamination, was asked to differentiate between good and contaminated ampules on the witness stand he failed to distinguish between them. Consequently, the case was dismissed. Any attempt to devise or analyze visible particle quality limits that is not based on the probabalistic nature of the accept/reject decision process can only result in the frustration and failure experienced by the F.D.A. expert in 1940. In the GMP philosophy, the introduction of any new device or system must be preceded by a validation demonstration. This is to ensure that the new device or system functions at least as well as the device or system to be replaced. The validation of semi- and fully automated systems for the detection of particle contamination rests upon the statistically replicable assessment of the security achieved with human inspection performance. Any attempt to validate an alternative inspection system without a knowledge of its probabalistic nature and the probabalistic nature of the human inspection benchmark performance

Algorithms↗

Molecular biology of cervical myelopathy and spinal cord injury: role of oligodendrocyte apoptosis.

BACKGROUND CONTEXT: Rational design of treatment strategies for cervical myelopathy and spinal cord injury requires a working knowledge of the molecular biology underlying these pathological processes. The cellular process of apoptosis is an important component of tissue and organ development as well as the natural response to disease and injury. Recent studies have convincingly demonstrated that apoptosis also plays a pivotal role in numerous pathological processes, contributing to the adverse effects of various diseases and traumatic conditions. A growing body of evidence has implicated apoptosis as a key determinant of the extent of neurological damage and dysfunction after acute spinal cord injury and in chronic cervical myelopathy. PURPOSE: To provide clinicians and research investigators interested in spinal cord injury and myelopathy with a practical and up-to-date basic science review of cellular apoptosis in the context of spinal cord pathology. STUDY DESIGN/SETTING: A review of recently published or presented data from molecular biological, animal model and human clinical studies. METHODS: A computer-based comprehensive review of the English-language scientific and medical literature was performed in order to identify relevant publications with emphasis given to more recent studies. RESULTS: Investigation into the role of apoptosis in spinal cord injury and myelopathy has drawn the interest of an increasing number of researchers and has yielded a substantial amount of new information. CONCLUSIONS: Apoptosis is a fundamental biological process that contributes to preservation of health as well as development of disease. There is now strong evidence to support a significant role for apoptosis in secondary injury mechanisms after acute spinal cord injury as well in the progressive neurological deficits observed in such conditions as spondylotic cervical myelopathy.

Animals↗

Speech-sound-selective auditory impairment in children with autism: they can perceive but do not attend.

In autism, severe abnormalities in social behavior coexist with aberrant attention and deficient language. In the attentional domain, attention to people and socially relevant stimuli is impaired the most. Because socially meaningful stimulus events are physically complex, a deficiency in sensory processing of complex stimuli has been suggested to contribute to aberrant attention and language in autism. This study used event-related brain potentials (ERP) to examine the sensory and early attentional processing of sounds of different complexity in high-functioning children with autism. Acoustically matched simple tones, complex tones, and vowels were presented in separate oddball sequences, in which a repetitive "standard" sound was occasionally replaced by an infrequent "deviant" sound differing from the standard in frequency (by 10%). In addition to sensory responses, deviant sounds elicited an ERP index of automatic sound-change discrimination, the mismatch negativity, and an ERP index of attentional orienting, the P3a. The sensory sound processing was intact in the high-functioning children with autism and was not affected by sound complexity or "speechness." In contrast, their involuntary orienting was affected by stimulus nature. It was normal to both simple- and complex-tone changes but was entirely abolished by vowel changes. These results demonstrate that, first, auditory orienting deficits in autism cannot be explained by sensory deficits and, second, that orienting deficit in autism might be speech-sound specific.

Auditory Diseases, Central↗

Electrophysiological evidence of automatic early semantic processing.

This study investigates the automatic-controlled nature of early semantic processing by means of the Recognition Potential (RP), an event-related potential response that reflects lexical selection processes. For this purpose tasks differing in their processing requirements were used. Half of the participants performed a physical task involving a lower-upper case discrimination judgement (shallow processing requirements), whereas the other half carried out a semantic task, consisting in detecting animal names (deep processing requirements). Stimuli were identical in the two tasks. Reaction time measures revealed that the physical task was easier to perform than the semantic task. However, RP effects elicited by the physical and semantic tasks did not differ in either latency, amplitude, or topographic distribution. Thus, the results from the present study suggest that early semantic processing is automatically triggered whenever a linguistic stimulus enters the language processor.

Adolescent↗

The impact of the public hearing process on the HSP and AIP of an HSA: an evaluative case study.

This paper evaluates the public hearing process and discusses some implications and ramifications of a public hearing process within one health systems agency (HSA). Standards for a public hearing are outlined. The standards include the utilization of logic and simple language in the preparation of the proposal, the delineation of public consent and public opinion, clarification of the intent of the public hearing, the preparation of the public for the hearing, and the post-hearing work program. This evaluative study indicates that the public hearing process had minimal direct effect on the HSP and AIP but substantial indirect effects. Indirect effects included influencing the content and issues, defining linkages, delineation of public consent and public opinion, and heightening a sense of political feasibility and public credibility. Equally important was the staff awareness of the political-social climate of the region, the governing board and the DHEW Guidelines. Recommendations for HSAs are also developed. These include the development of a responsive mechanism, the "stimulation" of proponents, education on the nature of the public hearing process, and clarification of the nature of the public interest.

Communication↗

The probability of causal conditionals.

Conditionals in natural language are central to reasoning and decision making. A theoretical proposal called the Ramsey test implies the conditional probability hypothesis: that the subjective probability of a natural language conditional, P(if p then q), is the conditional subjective probability, P(q/p). We report three experiments on causal indicative conditionals and related counterfactuals that support this hypothesis. We measured the probabilities people assigned to truth table cases, P(pq), P(p notq), P( notpq) and P( notp notq). From these ratings, we computed three independent predictors, P(p), P(q/p) and P(q/ notp), that we then entered into a regression equation with judged P(if p then q) as the dependent variable. In line with the conditional probability hypothesis, P(q/p) was by far the strongest predictor in our experiments. This result is inconsistent with the claim that causal conditionals are the material conditionals of elementary logic. Instead, it supports the Ramsey test hypothesis, implying that common processes underlie the use of conditionals in reasoning and judgments of conditional probability in decision making.

Analysis of Variance↗

The Listening Skills Test--a new instrument to assess children's pragmatic ability.

Research has established that the development of autonomous (as opposed to collaborative) communication skills, using referential communication speaker and listener tasks, develops only slowly during the primary school years. Such a finding has implications for the classroom which puts a premium on independent language processing. Although the importance of oral language is recognised in the National Curriculum, there has been little attempt to assess the ability formally. The Listening Skills Test is a standardised pragmatic instrument focusing on the 3 1/2-7 years age group. The test is in four parts and assesses the ability to make judgements about the efficacy of verbal messages or instructions. Tasks include relating messages to arrays of pictorial items, making judgements about statements that refer to one complex picture, marking routes on a street plan in response to an extended set of instructions, and the ability to evaluate purely verbal utterances. The overall aim of the test is to assess children's ability to make sense on their own of verbal information in a decontextualised situation thought to represent the nature of much transactional communication in the classroom. Suggestions for remediation that have arisen from research conducted by the authors are also discussed.

Child↗

Growth patterns in the developing brain detected by using continuum mechanical tensor maps.

The dynamic nature of growth and degenerative disease processes requires the design of sensitive strategies to detect, track and quantify structural change in the brain in its full spatial and temporal complexity. Although volumes of brain substructures are known to change during development, detailed maps of these dynamic growth processes have been unavailable. Here we report the creation of spatially complex, four-dimensional quantitative maps of growth patterns in the developing human brain, detected using a tensor mapping strategy with greater spatial detail and sensitivity than previously obtainable. By repeatedly scanning children (aged 3-15 years) across time spans of up to four years, a rostro-caudal wave of growth was detected at the corpus callosum, a fibre system that relays information between brain hemispheres. Peak growth rates, in fibres innervating association and language cortices, were attenuated after puberty, and contrasted sharply with a severe, spatially localized loss of subcortical grey matter. Conversely, at ages 3-6 years, the fastest growth rates occurred in frontal networks that regulate the planning of new actions. Local rates, profiles, and principal directions of growth were visualized in each individual child.

Adolescent↗

Patterns of phonological and memory processing in beginning readers and spellers of Greek.

This study examined the patterns of reading and spelling performance of first-grade Greek children who either were facing difficulties in literacy acquisition or were normal achievers. In addition, we studied the relationship between obtained literacy development levels and the children's phonological awareness and ability to retain phonological information in short-term memory. The participants were tested in the reading of single letters, letter clusters, words, and nonwords, as well as in word and nonword spelling. Furthermore, their phonological processing knowledge was assessed via a battery of phonological awareness tasks and short-term memory phonetic-representation tasks. The main findings of the study were as follows: (a) Accurate decoding of Greek was achieved by almost every young child (attributed mainly to the nature of the Greek writing system); (b) the time the children needed to process a written item was the crucial index of their difficulty in literacy acquisition; (c) spelling was performed by deriving the orthographic form of a word on the basis of sound-spelling correspondence knowledge; (d) although the children with difficulties in literacy development had achieved a satisfactory performance in phonological processing, their performance was nevertheless significantly lower than that of the normal achievers; and (e) phonemic awareness and speech rate tasks were among the best predictors of learning to read and spell Greek words.

Awareness↗

Learning and memory disorders and their assessment.

Brain lesions cause memory to break down in several distinct ways in people. First, cortical lesions cause disturbances in short-term memory. Second, other cortical lesions disturb the retrieval of previously well-established semantic and episodic memories. Third, frontal cortex dysfunction seems to be related to a memory syndrome caused by a breakdown in the ability to plan and carry out elaborative processing. Fourth, and most explored, is the amnesic syndrome(s), caused by limbic system or diencephalic lesions. Other less-studied forms of memory breakdown almost certainly exist and some memory syndromes are compounded from these more basic deficits. Appropriate assessment of memory disorders must take this heterogeneity and complexity into account, and is important not only for clinical purposes but also to gain further insight into the precise nature of the different kinds of breakdown. The major theoretical and clinical requirements that such assessment procedures must meet are outlined.

Alzheimer Disease↗

Geometrics of knowledge.

It is argued that knowledge representations formalized through pattern theoretic structures are geometric in nature in the following sense. The configurations and resulting patterns appearing in such representations exhibit invariances with respect to the similarity groups and are characterized topologically through their connection types. Starting with a special pattern from microbiology, it is shown how the basic pattern theoretic concepts are introduced in general and what their function is in representing knowledge. Variance/invariance of the patterns is discussed in geometric language. The measures on the configuration spaces are implemented by difference/differential equations which are used as a basis for computer algorithms.

Algorithms↗

Linguistic reference performance in parents of schizophrenic patients.

Clinicians have often reported observing subtle signs of thought disorder or communication difficulties in parents of schizophrenic patients. Ascertaining empirically whether these impressions are valid and, if so, clarifying the nature of such disturbances is important for at least two reasons. First, it could assist in elucidating the etiologies of the illness. If distinguishing parental characteristics could be clearly defined, then further research could be undertaken to determine to what extent they represent genetic vulnerability markers, pathogenic environmental influences, or behavioral responses to having a disordered offspring. Secondly, it could facilitate our understanding of the cognitive processes involved in schizophrenia or in the constitutional vulnerability to schizophrenia.

Adult↗