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Results for “knowledge graphs”

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PubMed1990

A computer system for contact dermatitis: graphical representation of data.

An overview is given of the computer applications we have developed over the last twelve years in the field of contact dermatitis. The dissemination of exposure lists to sensitised individuals and the development of a knowledge-based system are mentioned only briefly. Priority here is given to the explanation of the graphical representation of the patient data collected since 1978 on 12,000 patients referred to three contact dermatitis units. More than a hundred parameters of each patient have been collected in a database. Several graphs are given of these data and are discussed in detail.

Adolescent↗

PubMed1992

Dynamics for communications data.

To create a complex dynamical model for a complex system, it is normally necessary to have a directed graph of the network, a dynamical model for each node, and a coupling function for each directed edge. But in many applications, the only observable data consists of communications from one node to another. In this situation, the modeler may infer a complex dynamical model for the network without any explicit knowledge of the independent dynamical behavior of the component systems (nodes). Here we present one procedure for this type of modeling problem, inspired by the attractor reconstruction procedure of chaos theory. Part of this proposal consists of a strategy for computer graphic presentation of the interactive dynamics of the complex system (or social network of dynamical schemes) called a netscope. We can imagine applications to diverse situations, such as decision groups, management, forecasting, international relations, classroom monitoring, therapy (personal, family, group, etc.) and distributed processors, to name a few.

Communication↗

PubMed1983

The case report. I. Guidelines for preparation.

A case report, if prepared properly, is a valuable educational device to describe an unusual clinical syndrome, association, reaction, or treatment. If a case advances basic understanding of a disorder, increases clinical skill, or suggests useful research, it is worthy of publication. Conciseness is paramount. The description of the case should contain only pertinent positive and negative findings. Irrelevant material or excessive detail can obscure the essence of a report and repel editors and readers. The discussion should emphasize the salient features of the case, show their relation to previous knowledge, interpret their significance, draw conclusions or generalizations about future cases when warranted by the evidence presented, or suggest further possible studies. Information withheld by the patient and unjustified speculation can nullify the value of a case report. Illustrations add visual appeal and enhance the educational value of a report. Tables and graphs should reduce any statistical data to readily interpretable form. All visual supplements should be simple, compact, and self-contained. Appropriate documentation is desirable, but only essential citations need be included, and the author should have carefully reviewed and verified all references used. Begin with a clear title and end with an informative Summary. A useful case report is factual, concise, logically organized, clearly presented, and readable. The three primary principles to remember: (1) Make sure the case warrants publication. (2) Include only pertinent information. (3) Be concise.

Humans↗

PubMed1996

A knowledge-based model construction approach to medical decision making.

We present a framework for representing the probabilistic effects of actions and contingent treatment plans. Our language has a well-defined declarative semantics and we have developed an implemented algorithm (named BNG) that generates Bayesian networks (BN) to compute the posterior probabilities of queries. In this paper we address the problem of projecting a contingent treatment plan by automatically constructing a structure of interrelated BNs, which we call a BN-graph, and applying the available propagation procedures on it. To address the optimal plan generation, we base our approach on the observation that normally the target plan space has a well-defined structure. We provide a language to describe plan spaces which resembles a programming language with loops and conditionals. We briefly present the procedures for finding the optimal plan(s) from such specified plan spaces.

Acute Disease↗

PubMed1993

Hierarchical functional organization of formal biological systems: a dynamical approach. III. The concept of non-locality leads to a field theory describing the dynamics at each level of organization of the (D-FBS) sub-system.

In paper I, the construction of the graph of interactions, called (O-FBS), was deduced from the 'self-association hypothesis'. In paper II, a criterion of evolution during development for the (O-FBS), which represents the topology of the biological system, was deduced from an optimum principle leading to specific dynamics. Experimental verification of the proposed extremum hypothesis is possible because precise knowledge of the dynamics is not necessary; only knowledge of the monotonic variation of the number of sinks is required for given initial conditions. Essentially, the properties of the (O-FBS) are based on the concept of non-symmetry of functional interactions, as shown by the 'orgatropy' function (paper II). In this paper, a field theory is proposed to describe the (D-FBS), i.e. the physiological processes expressed by functional interactions: (i) physiological processes are conceived as the transport of a field variable submitted to the action of a field operator; (ii) because of hierarchy, this field theory is based on the concept of non-locality, and includes a non-local and non-symmetric interaction operator; (iii) the geometry of the structure contributes to the dynamics via the densities of structural units; and (iv) because a physiological process evolves on a particular timescale, it is possible to classify the levels of organization according to distinct timescales, and, therefore, to obtain a 'decoupling' of dynamics at each level. Thus, a property of structurality for a biological system is proposed, which is based on the finiteness of the velocity of the interaction, thus, with distinct values of timescales for the construction of the hierarchy of the system. Three axioms are introduced to define the fields associated with the topology of the system: (i) the existence of the fields; (ii) the decoupling of the dynamics; and (iii) the ability of activation-inhibition. This formulation leads to a self-coherent definition of auto-organization: an FBS is self-organized if it goes from one stable state for the (D-FBS) to another under the influence of certain modifications of its topology, i.e. a modification of the (O-FBS). It is shown that properties deduced with this formalism give the relationship between topology and geometry in an FBS, and particularly, the geometrical re-distribution of units.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1979

[Activation of student cognitive activities in the process of teaching medical microbiology].

The main trends of methodical work conducted at the chair of microbiology of Orenburng Medical Institute are presented. For the purpose of activation of cognition activity of students during medical microbiology teaching the following methods were applied: presentation of the teaching material, creation of visual teaching methods in a single methodical plan in accordance with the logic structure graphs of the subject as a whole, its individual sections and themes; introduction of problem teaching method, solution of practical tasks of the II and III learning level; introduction of scientific achievements of the chair into the teaching process. Result of evaluation of the efficacy of the teaching-methodical work of the chair carried out demonstrated that knowledge of the principal microbiology problems in the students and interns persisted for long periods of time.

Cognition↗

PubMed1982

An approach to completely automatic comparison of two-dimensional electrophoresis gels.

The problem addressed is that of determining the similarities and differences appearing in a sequence of two-dimensional polyacrylamide gels where we have no a priori knowledge of the intensity and spatial distribution of the protein spots. It is assumed that the gels are not in precise registration. An attempt is being made to develop a completely automatic program for use in genetic studies, which will compare a sequence of three gels run on samples from father, mother, and child. The program constructs a graph by using as nodes those spot cues that exceed a given intensity threshold. The graphs are then compared to determine an initial subset of spots that are common to all three gels. From this subset of common spots the program then determines whether the remaining graph differences are real or result from quantitative variation causing spots to fall below threshold.

Adult↗

PubMedDate not supplied

[Pressure distribution on the sole of the human foot while standing and walking, barefoot and with shoes].

For more than a century, scientists and practicians of orthopedic shoe production have been increasing their knowledge on the normal statics and dynamics of the lower extremities as well as on innate or often acquired posture anomalies and foot deformities. Even amongst young adults, barely half of one percent has so-called "inconspicuous" feet without restrictive signs of foot deformities. Consequently, the resulting primary illnesses and secondary injuries must be treated. Quantitative pressure distribution graphs in isobaric representation at the heel barefoot when standing and walking were determined by means of an improved, locally fixed device by Elftman and Helm. For the first time, a newly developed mobile measuring process allows measuring pressures at the heel inside the shoe while standing as well as while walking, running or jumping. The rolloff motion of the heel allowed the determination of a "maximum pressure line." Orthopedic recommendations for the production of true-to-form and true-to-function shoes for walking and sports shoes are included.

Biomechanical Phenomena↗

PubMed1990

[Mortality analysis: when is single evaluation of the basic cause of death allowable, when should multi-causality be assessed?].

Data quality is often a critical point in mortality studies. The purpose of the present report is to present criteria for assessing the value of death-certificate-based mortality studies. For this purpose all 57,454 Swiss death certificates of the year 1979 were analysed. Reliability of the diagnosis listed on the death certificate was investigated by comparing for each case of a linked sample of 12,478 deaths the cause of death with medical information available from the hospital record. Retrieval rates (percentage of cases for which the given diagnosis appears in both registries) were calculated for the primary diagnoses named in each data set. These can be considered as measures of reliability of diagnoses. The graphs given indicate a high reliability for cancers and accidents. Reliability was lower for other causes of death such as cardiovascular diseases, diabetes mellitus, rheumatic diseases. Restriction to the primary cause of death can be accepted for most cancers, accidents and violent deaths. For other causes of death, decisions must be made individually and multicausal analysis may be indicated. In addition, knowledge of the reliability of the diagnoses of interest is necessary for the interpretation of results derived from death certificate-based mortality studies.

Cause of Death↗

PubMed1994

Internal temperature calibration for 1H NMR spectroscopy studies of blood plasma and other biofluids.

A method for temperature calibration of human blood plasma and cerebrospinal fluid (CSF) samples inside a high resolution NMR spectrometer is presented. This calibration is based on the temperature dependence of the chemical shift difference between the water signal and that from the H-1 proton of endogenous alpha-glucose or, in some circumstances, beta-glucose. This dependence can be fitted using a second-order polynomial equation and functions for both human blood plasma and human CSF are given. Similar graphs could easily be generated for other fluids. The blood plasma calibration appears to be accurate to +/- 0.9 K in test samples. The use of the blood plasma calibration graph has also been evaluated using the 1H NMR spectra of CSF and shown to overestimate the CSF internal temperature by ca 1.3 K. This approach should have a general applicability to blood plasma and CSF samples from normal and pathological situations or from other species, because there are unlikely to be large changes in ionic strength or pH even in disease states. Knowledge of the exact internal temperature of plasma samples is likely to be of particular importance in the investigation of lipid and lipoprotein interactions because of the significant temperature dependence of lipid and lipoprotein NMR linewidths in such samples.

Body Fluids↗

PubMed2026

Genomic insights into natural selection in recent human history.

For over a century, scientists have debated the extent to which genetic and phenotypic variation among present-day humans is the result of natural selection - in which heritable traits influence survival or reproduction - versus neutral processes such as genetic drift or population history. The initial sequencing of the human genome and subsequent population resequencing studies enabled genome-scale searches for signatures of selection in present-day genomes. This first generation of genome-wide selection scans identified many targets but left open questions about the timing and nature of selection, making it challenging to identify environmental and biological drivers. Recent methodological advances based on reconstructing ancestral recombination graphs have increased the potential power and resolution of selection scans based on present-day genomes, while the availability of new data on ancient DNA has facilitated the direct reconstruction of genetic change through time. However, there is little consensus on how to use these data to detect and interpret signatures of selection, while avoiding confounders. Here, we review the current state of knowledge about the impact of selection on human genomic diversity and highlight conceptual advances in our understanding of human evolution over the past 10,000 years.

Journal Article↗

PubMed1996

Knowledge on collection and analysis of health information of state certified nurses from rural health centres, Masvingo Province.

OBJECTIVE: To assess the knowledge on collection and analysis of health information of State Certified Nurses (SCNs) from Rural Health Centres (RHCs), Masvingo Province. DESIGN: Three methods were employed during the assessment: a questionnaire, observation, and practical exercises (calculations). SETTINGS: 19 RHCs in Chiredzi and Bikita Districts, Masvingo Province. SUBJECTS: 19 SCNs in charge of Rural Health Centres. MAIN OUTCOME MEASURES: Ability to analyze and utilize health information, availability of graphs, master cards summaries (health diaries) and minutes. Presence or absence of catchment maps, charts on population breakdown and immunization coverage charts. Ability to calculate some rates and percentages. RESULTS: Of 19 SCNs in charge who said they do school health programmes, only six had any evidence that they do so; of nine SCNs in charge who reported that they have graphs on weekly reported diseases, only four had graphs displayed. Of 18 SCNs in charge who said they had immunization coverage targets only 11 had charts displayed; of 18 SCNs in charge who reported that they discuss health problems in their areas, only one had minutes documenting the discussion. Only six of 19 SCNs at rural centres could calculate coverage rates and only one of 19 SCNs at health centres could calculate dropout rates. CONCLUSION: Comparing the questionnaire responses with the findings from observations, it can be seen that more is reported than is actually done. From the practical exercises it was evident that the ability to do basic calculations was often lacking.

Data Collection↗

PubMed1976

Lateralization in stroke syndromes as a factor in ambulation.

Lateralization should not be ignored in any rehabilitation program for patients with stroke syndromes. Despite the known differences resulting from the localization in the dominant versus the nondominant hemisphere (spatial perception, speech, etc.), practical application of this knowledge in gait training is sparse. The authors looked into different stages of ambulation and the time sequence between these stages and the onset of disease. Standing and walking in parallel bars and outside, as well as elevation activities were given numerical values in an effort to assess abilities quantitatively. The assessment of each patient was recorded graphically (stage of gait against time) and then the different graphs were summated in order to form a common right hemiparetic versus left hemiparetic curve. This study of 236 out of 298 patients (129 left hemiparetics and 107 right ones) showed the following: (1) The right hemiparetics progressed more rapidly in all stages of ambulation, statistically significant figures being obtained for the first two stages; (2) a greater percentage of right versus left hemiparetics reached the assigned levels of ambulation: and (3) 89% out of the 236 patients included in our study were able to ambulate in parallel bars, 81% outside the bars and 38.5% were proficient in stair climbing. Out of the original total number of patients (298), 64% were able able to ambulate outside the bars.

Adolescent↗

PubMed1991

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↗

PubMed1995

Mathematical model of oxygen transport: a teaching aid for normal physiology adaptable to extracorporeal oxygenation circuits.

The ultimate aim of most intensive care therapies is to improve tissue oxygen delivery; consequently, a detailed knowledge of this area of physiology is important to a wide range of Critical Care Staff. We describe a simple mathematical model of oxygen transport that was initially written as a training aid for extracorporeal oxygenation training. The model has subsequently proved useful for explaining the determinants of oxygen transport to a broader audience. It is based on simple linear equations and is easily displayed with a standard computer spreadsheet. Apart from its teaching value, the model can also generate a graph of oxygen saturation vs. inspired oxygen fraction for different degrees of pulmonary shunt. This provides a noninvasive method for determining the magnitude of pulmonary venous admixture and may also prove to have some clinical value.

Biological Transport, Active↗

PubMedDate not supplied

A formal model of family medicine.

BACKGROUND: The American Board of Family Practice is developing a computer-based recertification process. An optimal implementation requires a formal model of family medicine, which will become the basis for a knowledge base. DESIGN: The proposed model of family medicine contains six entities: Population, Record, Agents of Change, Health States, Findings, and Courses of Action. The model illustrates 15 important relations between entities. For instance: Health States Lead to Health States, and Findings Associate with Health States. These two relations describe natural history, manifestations of disease, and the effects of medical interventions and risk factors. Because time is such an important aspect of primary care, nearly all numeric data are represented as graphs of possible values over time, called Patterns, which include details about periodicity. Patterns and other aspects of the model provide a means of describing covariance between observations, such as the influence of height on weight. RESULTS: The model reflects many family practice activities and suggests some formal descriptions of family practice. For instance, diagnostic activities focus largely on classifying early or short segments of Patterns in Findings. Most medical interventions attempt to alter either the probability distributions in a Lead-to relation or the impact of a Finding. CONCLUSION: The proposed model of family medicine could find uses in many applications, including computer-based tests, medical records, reference systems, and decision support tools.

Family Practice↗

PubMed1992

Mathematical assessment of the spatial distribution of Langerhans cells in guinea pig epidermis.

Two mathematical indexes, Hopkins-Skellam index (HSI) and Morisita index (MI), were applied to assess the distribution of ATPase-stained epidermal Langerhans cells (ELC) in the guinea pig skin. To our knowledge, this is the first report in which the degree of regularity has been expressed numerically by computation based on theoretical equations. The regularity of ELC in the normal skin was confirmed by the value of HSI (P < 0.0001). In the topical steroid applied skin, the number of ELC decreased significantly but the value of HSI was similar to that of the normal skin; while in the ultraviolet B (UVB) exposed skin, both number of ELC and regularity of ELC distribution decreased significantly. The graph of MI for the UVB exposed skin clearly showed that the distribution of ELC had local clumps. The two indexes, HSI and MI have been quite useful for determining the regularity of ELC. These indexes may have a wide application to other cells.

Animals↗

PubMed1988

Biological applications of the SAS system: an overview.

The SAS system provides biologists with a flexible, easy to use software package for data analysis. Through a combination of data management tools, a wide variety of pre-programmed procedures for sorting, graphing, and statistical analysis and a sophisticated programming language, SAS software can perform all analytical needs for most problems. The recent availability of SAS software on mainframes other than IBM, and more recently on the microcomputer, means that most scientists can have access to the software. In this review we discuss the structure of the SAS language and demonstrate its power in the analysis of biological problems. Although to a lesser extent now than originally, the SAS system is statistically oriented and a working knowledge of statistics is recommended before using its statistical capabilities. However, all biologists will find its data management and summarization capabilities very useful.

Biology↗