PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Knowledge Sources”

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 217 records · Page 12Linked to original sources
PubMed2006

Superficial siderosis of the CNS: report of three cases and review of the literature.

Superficial siderosis (SS) is a rare entity. A chronic subarachnoid hemorrhage (SAH) leads to the deposition of ferric pigments and ions in the surface of the central nervous system (CNS). The cause of this hemorrhage is identified in half of the cases. The disease progresses slowly and the damage is often irreversible by the time diagnosis is established. The management focuses on the identification and ablation of the bleeding source. Knowledge about this entity is based on sporadic reports. We describe three cases of superficial siderosis and briefly review the literature.

Brain↗
PubMed2005

Amplification of Terminologia anatomica by French language terms using Latin terms matching algorithm: a prototype for other language.

OBJECTIVE: Terminologia anatomica is the new standard in anatomical terminology. This terminology is available only in Latin and English and its worldwide adoption is subject to the addition of terms from others languages. On the other hand, Nomina anatomica, the previous standard, has been widely translated. Aim of this work was to append foreign terms to Terminologia by using similarity-matching algorithm between its Latin terms and those from Nomina. METHODS: A semi-automatic matching of Latin terms from Terminologia with those of Nomina was performed using a string-to-string distance algorithm and manual assessment. We used a French-Latin version of Nomina together with Terminologia and we suggested French terms for Terminologia. Coverage was evaluated by the number of exact and approximate matches. A target of 78% was set due to the higher number of terms in Terminologia compared to Nomina. Relevance was estimated by manually comparing the meanings of the English and French terms related to the same Latin term. The question was whether they refer to the same anatomical structure. RESULTS: Exact or approximate matches were found for 5982 terms (76.5%) of Terminologia. Our results indicated that more than 75% of the terms from Terminologia came from Nomina, most of them were left unchanged and all were used with the same meaning. CONCLUSION: This method produces relevant results, reaching our 78% target. The method is based only on Latin terms and can be used for other languages. We consider this work as a starting point for adding terms to other knowledge sources, such as the foundational model of anatomy or the Unified Medical Language System (UMLS).

Algorithms↗
PubMed2003

Consistency across the hierarchies of the UMLS Semantic Network and Metathesaurus.

OBJECTIVE: To develop and test a method for automatically detecting inconsistencies between the parent-child is-a relationships in the Metathesaurus and the ancestor-descendant relationships in the Semantic Network of the Unified Medical Language System (UMLS). METHODS: We exploited the fact that each Metathesaurus concept is assigned one or more semantic types from the UMLS Semantic Network and that the semantic types are arranged in a hierarchy. We compared the semantic types of each pair of parent and child concepts to determine if the types "explained" the Metathesaurus is-a relationships. We considered cases where the semantic type of the parent was neither the same as, nor an ancestor of, the semantic type of the child to be "unexplained." We applied this method to the January 2002 release of the UMLS and examined the unexplained cases we discovered to determine their causes. RESULTS: We found that 17022 (24.3%) of the parent-child is-a relationships in the UMLS Metathesaurus could not be explained based on the semantic types of the concepts. Causes for these discrepancies included cases where the parent or child was missing a semantic type, cases where the semantic type of the child was too general or the semantic type of the parent was too specific, cases where the parent-child relationship was incorrect, and cases where an ancestor-descendant relationship should be added to the UMLS Semantic network. In many cases, the specific cause of the discrepancy cannot be resolved without authoritative judgment by the UMLS developers. CONCLUSIONS: Our method successfully detects inconsistencies between the hierarchies of the UMLS Metathesaurus and Semantic Network. We believe that our method should be added to the set of tools that the UMLS developers use to maintain and audit the UMLS knowledge sources.

Abstracting and Indexing↗
PubMed2005

Global workspace theory of consciousness: toward a cognitive neuroscience of human experience.

Global workspace (GW) theory emerged from the cognitive architecture tradition in cognitive science. Newell and co-workers were the first to show the utility of a GW or "blackboard" architecture in a distributed set of knowledge sources, which could cooperatively solve problems that no single constituent could solve alone. The empirical connection with conscious cognition was made by Baars (1988, 2002). GW theory generates explicit predictions for conscious aspects of perception, emotion, motivation, learning, working memory, voluntary control, and self systems in the brain. It has similarities to biological theories such as Neural Darwinism and dynamical theories of brain functioning. Functional brain imaging now shows that conscious cognition is distinctively associated with wide spread of cortical activity, notably toward frontoparietal and medial temporal regions. Unconscious comparison conditions tend to activate only local regions, such as visual projection areas. Frontoparietal hypometabolism is also implicated in unconscious states, including deep sleep, coma, vegetative states, epileptic loss of consciousness, and general anesthesia. These findings are consistent with the GW hypothesis, which is now favored by a number of scientists and philosophers.

Cognition↗
PubMed2002

Evaluation of two different models of semi-automatic knowledge acquisition for the medical consultant system CADIAG-II/RHEUMA.

As part of a plan to promote semi-automatic knowledge acquisition for the medical consultant system CADIAG-II/RHEUMA, this study sought to explore and cope with the variability of results that may be anticipated when performing knowledge acquisition with patient data from different patient settings. Patient data were drawn both from a published study for the classification of rheumatoid arthritis (RA) and from a large database of rheumatological patient charts developed for the CADIAG-II/RHEUMA system. An analysis of the relationships between RA and selected CADIAG-II/RHEUMA symptoms was done using two models. In one of them, we controlled for the differences in baseline frequencies of symptoms and diseases in the two study populations as an important factor influencing the results of the calculations. Other factors that were identified included inconsistent definitions of symptoms and diseases, and the different composition of study groups in the two study populations. By eliminating differences in baseline frequencies as the most important bias, the results obtained from the two different knowledge sources became more consistent. All remaining inconsistencies and uncertainties about the contribution and relative importance of the factors were formalized using fuzzy intervals.

Arthritis, Rheumatoid↗
PubMed1998

Case-based reasoning in IVF: prediction and knowledge mining.

In vitro fertilization (IVF) is a medically-assisted reproduction technique, enabling infertile couples to achieve successful pregnancy. Given the unpredictability of the task, we propose to use a case-based reasoning system that exploits past experiences to suggest possible modifications to an IVF treatment plan in order to improve overall success rates. Once the system's knowledge base is populated with a sufficient number of past cases, it can be used to explore and discover interesting relationships among data, thereby achieving a form of knowledge mining. The article describes the TA3IVF system--a case-based reasoning system which relies on context-based relevance assessment to assist in knowledge visualization, interactive data exploration and discovery in this domain. The system can be used as an advisor to the physician during clinical work and during research to help determine what knowledge sources are relevant for a treatment plan.

Artificial Intelligence↗
PubMed2001

Medical knowledge reengineering--converting major portions of the UMLS into a terminological knowledge base.

We describe a semi-automatic knowledge engineering approach for converting the human anatomy and pathology portion of the UMLS metathesaurus into a terminological knowledge base. Particular attention is paid to the proper representation of part-whole hierarchies, which complement taxonomic ones as a major hierarchy-forming principle for anatomical knowledge. Our approach consists of four steps. First, concept definitions are automatically generated from the metathesaurus, with LOOM as the target language. Second, integrity checking of the emerging taxonomic and partonomic hierarchies is automatically carried out by the terminological classifier. Third, terminological cycles and inconsistencies are manually eliminated and, in the last step, the knowledge base built this way is incrementally refined by a medical expert. Our experiments were run on a terminological knowledge base which is composed of 164,000 concepts and 76,000 relations. Empirical evidence for the lack of logical consistency, adequacy and improper granularity of the UMLS knowledge source is given, and finally, assessments of what kind of efforts are needed to render the formal target representation structures complete and empirically adequate.

Anatomy↗
PubMed1999

Development of a cross-thesaurus with Internet-based refinement supported by UMLS.

Combinatorial terminological systems are appearing, to solve the issues related to flexibility and precision of representation requested by modern healthcare information systems and in particular by messaging standards. The development of a robust system of descriptors ('cross-thesaurus') is a crucial activity in the production of combinatorial terminological systems. We developed a tool (I-BROWSE) to produce a cross-thesaurus by analysing existing terminological corpora. To facilitate the work of experts and to produce re-usable results, our application interacts via the Internet with the UMLS Knowledge Sources Server. We applied our tool on 6372 dissections on surgical procedures produced in the project GALEN-IN-USE, as a part of the internal Quality Assurance Program. Support from UMLS seems mostly promising about descriptors on , , and . Additional assistance can be given to domain experts on less frequent descriptors on pervasive modifiers. We plan to apply our tool also to production of terminological standards in CEN, as a part of a world-wide process of gradual convergence and transformation of coding systems into second-generation systems and terminological services.

Databases as Topic↗
PubMed2006

Topology of music recommendation networks.

We study the topology of several music recommendation networks, which arise from relationships between artist, co-occurrence of songs in play lists or experts' recommendation. The analysis uncovers the emergence of complex network phenomena in these kinds of recommendation networks, built considering artists as nodes and their resemblance as links. We observe structural properties that provide some hints on navigation and possible optimizations on the design of music recommendation systems. Finally, the analysis derived from existing music knowledge sources provides a deeper understanding of the human music similarity perception.

Journal Article↗
PubMed2004

Lack of awareness of need to clean CFC-free metered-dose inhalers.

BACKGROUND: Chlorofluorocarbon (CFC)-free metered-dose inhalers (MDIs) were introduced into Australia in 1999. Device care instructions were modified (e.g., CFC-free salbutamol inhalers to be washed weekly), but this information was not communicated directly to health care professionals. OBJECTIVE: This pilot study aimed to assess the level of awareness of device care protocols for CFC-free MDIs by patients and their pharmacists. SETTING AND DESIGN: Purchasers of CFC-free MDIs were recruited from four community pharmacies. They were interviewed regarding information sources, knowledge of propellant change, and awareness of and adherence to device care protocols. The dispensing pharmacists were interviewed for knowledge of CFC-free device care. The primary outcome variable was awareness of the relevant device care protocol. RESULTS: Thirty-nine patients were interviewed. Most patients (77%) were aware of the change to CFC-free propellant. Only nine patients (23%) were aware of the need to wash the device holder, and four patients (10% of total) complied with the specified protocol. One of the ten dispensing pharmacists could describe correct device care protocols for the CFC-free MDIs. CONCLUSIONS: Although most patients are aware that MDIs are now CFC-free, there is a low level of awareness of the device care required for these inhalers, and a very low rate of compliance with recommended practice. Although the clinical impact of failing to wash the device holder is unclear, this added instruction may have substantial implications for patient satisfaction and medication delivery. Pharmaceutical manufacturers need to highlight to health care professionals any clinically important changes in device care instructions, so that appropriate information may be passed on to patients.

Australia↗
PubMed1995

The potential of computerized representations of anatomy in the training of health care providers.

The purpose of anatomy education is to develop the skills for anatomical reasoning, which is a requirement for performing a number of clinical tasks. Anatomical reasoning integrates an understanding of the three-dimensional (3-D) geometry of the body and its parts (the spatial domain of anatomical information) with an understanding of functional, developmental, pathological, and other relationships among anatomic entities (the symbolic domain of anatomical information). Traditional methods in anatomy have substantial shortcomings for representing and integrating these two information domains. Computer-based methods of knowledge representation have a great potential for overcoming the shortcomings and for promoting anatomical reasoning. To realize this potential, there is a need for (1) establishing 3-D electronic atlases of the human body; (2) generating models of symbolic anatomical information, and (3) developing computer programs (user interfaces) that integrate these knowledge sources and serve the needs of trainees and practitioners in different fields of the health sciences. The Digital Anatomist Program at the University of Washington has begun to build such a client-server framework for anatomical information, and its application for biomedical education is being evaluated.

Anatomy↗
PubMed2003

From case-based reasoning to problem-based learning.

Many medical schools today are questioning whether they should implement a problem-based learning (PBL) curriculum. Educators have raised serious questions regarding the efficiency of PBL and therefore recommend learning more about the cognitive processes developed by PBL before implementing it broadly. In addition, it is important to determine whether PBL best matches the human reasoning process. The authors' theoretical discussion examines the relationship between the case-based reasoning (CBR) model and the PBL model. CBR indicates that the knowledge source one uses while solving a new problem includes not only generalized rules or general cases, but often a memory of stored cases recording specific prior episodes. CBR enables the reasoner to recommend solutions to problems quickly and to propose solutions in domains that are not completely understood, such as medicine. The authors' analysis reveals a strong association between the CBR and PBL models, and thus it can be argued that PBL is a successful teaching method that should be encouraged by medical schools.

Curriculum↗
PubMed1992

Cardioembolic stroke.

Approximately 15% of ischemic strokes are the result of an embolism from a cardiac source. Patients with nonvalvular atrial fibrillation, acute myocardial infarction, ventricular aneurysm, rheumatic heart disease, prosthetic heart valves and other less common cardiac disorders are at an increased risk for cardioembolic stroke. Clinicians must distinguish cardioembolic from atherosclerotic strokes to provide unique management for each patient. The nurse plays a dynamic role in diagnosis, education and treatment of patients at risk or who have had a stroke from a cardiac source. Knowledge of the pathophysiologic mechanisms and treatment options is essential for the nurse to adequately manage patient care.

Anticoagulants↗
PubMed1999

Information fusion: application to data and model fusion for ultrasound image segmentation.

Nowadays, information fusion constitutes a challenging research topic. Our study proposes to achieve the fusion of several knowledge sources. This, in order to detect the esophagus inner wall from ultrasound medical images. After a brief description of information fusion concepts, we propose a system architecture including both model and data fusion. The data fusion is accomplished using fuzzy modeling, which can be seen as a monosensor/multiple sources data fusion system. The model fusion is performed using a full-adapted snake theory, which projects the fuzzy decision into the binary decision space.

Computer Simulation↗
PubMed2006

The relationship between viewing US-produced television programs and intentions to drink alcohol among a group of Norwegian adolescents.

The aim of this study was to examine the influence of exposure to US-produced television programs and family rules prohibiting alcohol use on the development of normative beliefs, expectancies, and intentions to drink alcohol in the next 12 months among a group of Norwegian adolescents who reported that they had not previously consumed alcohol. Data were collected via a survey administered to 622 eighth and ninth graders enrolled at ten junior highs in southeastern Norway. To examine these relationships we tested the fit of a structural equation model which was based on the Theory of Planned Behavior (Ajzen, 1988). Data from the non-drinkers (n= 392, 63% of the respondents) were used. To control for the influence of peer drinking on behavioral intentions, our model was tested under two group conditions: (1) those subjects reporting that they have no friends who drink alcohol and (2) those subjects reporting that they have one or more friends who drink. The findings indicate that the influence of TV exposure was a significant predictor (directly) of normative beliefs, expectancies (indirectly) and intentions to drink (both directly and indirectly) only for those subjects who reported having no friends who drink. For the group with non-drinking friends, family rules constrain intentions only indirectly by influencing normative beliefs. For those with friends who drink, however, family rules have a direct (inverse) effect on intentions. It is concluded that exposure to US-produced television programs functions as a limited knowledge source only for those subjects who had little or no personal experience with alcohol while the presence of family rules have limited impact on behavioral intentions.

Adolescent↗
PubMed1999

Density and molecular epidemiology of Aspergillus in air and relationship to outbreaks of Aspergillus infection.

After five patients were diagnosed with nosocomial invasive aspergillosis caused by Aspergillus fumigatus and A. flavus, a 14-month surveillance program for pathogenic and nonpathogenic fungal conidia in the air within and outside the University Hospital in Rotterdam (The Netherlands) was begun. A. fumigatus isolates obtained from the Department of Hematology were studied for genetic relatedness by randomly amplified polymorphic DNA (RAPD) analysis. This was repeated with A. fumigatus isolates contaminating culture media in the microbiology laboratory. The density of the conidia of nonpathogenic fungi in the outside air showed a seasonal variation: higher densities were measured during the summer, while lower densities were determined during the fall and winter. Hardly any variation was found in the numbers of Aspergillus conidia. We found decreasing numbers of conidia when comparing air from outside the hospital to that inside the hospital and when comparing open areas within the hospital to the closed department of hematology. The increase in the number of patients with invasive aspergillosis could not be explained by an increase in the number of Aspergillus conidia in the outside air. The short-term presence of A. flavus can only be explained by the presence of a point source, which was probably patient related. Genotyping A. fumigatus isolates from the department of hematology showed that clonally related isolates were persistently present for more than 1 year. Clinical isolates of A. fumigatus obtained during the outbreak period were different from these persistent clones. A. fumigatus isolates contaminating culture media were all genotypically identical, indicating a causative point source. Knowledge of the epidemiology of Aspergillus species is necessary for the development of strategies to prevent invasive aspergillosis. RAPD fingerprinting of Aspergillus isolates can help to determine the cause of an outbreak of invasive aspergillosis.

Air Microbiology↗
PubMedDate not supplied

A general natural-language text processor for clinical radiology.

OBJECTIVE: Development of a general natural-language processor that identifies clinical information in narrative reports and maps that information into a structured representation containing clinical terms. DESIGN: The natural-language processor provides three phases of processing, all of which are driven by different knowledge sources. The first phase performs the parsing. It identifies the structure of the text through use of a grammar that defines semantic patterns and a target form. The second phase, regularization, standardizes the terms in the initial target structure via a compositional mapping of multi-word phrases. The third phase, encoding, maps the terms to a controlled vocabulary. Radiology is the test domain for the processor and the target structure is a formal model for representing clinical information in that domain. MEASUREMENTS: The impression sections of 230 radiology reports were encoded by the processor. Results of an automated query of the resultant database for the occurrences of four diseases were compared with the analysis of a panel of three physicians to determine recall and precision. RESULTS: Without training specific to the four diseases, recall and precision of the system (combined effect of the processor and query generator) were 70% and 87%. Training of the query component increased recall to 85% without changing precision.

Diagnosis, Computer-Assisted↗