Diagnosis of rheumatism by means of universal criteria, obtained by the cybernetic method.
(1/32)
With a view to establishing standardized criteria for the diagnosis of rheumatism suitable for widespread use in polyclinics and in large-scale epidemiological investigations, 3000 adults and children with rheumatism or one of seven similar diseases were subjected to multiple screening in eight centres in the USSR using a specially prepared standard card and standard methods. The information obtained was processed by cybernetic methods. Following determination of the sensitivity, specificity, and informational value of 486 signs of rheumatism, 68 of the most indicative signs were selected as criteria of rheumatism. These were included in the final table and weighted according to their indicational value both individually and in groups as syndromes. Using the table it is possible by simple calculation, without using a computer, to arrive at an objective evaluation of the reliability of the clinical diagnosis of rheumatism in patients with one of a group of eight similar diseases. The final diagnostic table was tested on 562 patients selected epidemiologically or from polyclinics or clinics and was shown to result in a high degree of diagnostic precision (higher than 95%). (+info)
Mouse submandibular gland morphogenesis: a paradigm for embryonic signal processing.
(2/32)
Signal processing is the sine qua non of embryogenesis. At its core, any single signal transduction pathway may be understood as classic Information Theory, adapted as an open system such that, because of networking, the "receiver" is presented with more information than was initially signaled by the "source". Over 40 years ago, Waddington presented his "Epigenetic Landscape" as a metaphor for the hierarchical nature of embryogenesis. Mathematically, Waddington's landscape may be modeled as a neural net. The "black box" of the neural net is an interacting network of signal transduction pathways (using hormones, growth factors, cytokines, neurotransmitters, and others) which inform the Boolean logic gates. An emerging theme in developmental biology is that defined sets of epigenetic circuits are used in multiple places, at multiple times, for similar and sometimes different purposes during organogenesis. As we show here, submandibular gland embryonic and fetal development is a splendid paradigm of these epigenetic circuits and their phenotypic outcomes, such as branching and lumen formation. (+info)
MOTOR OUTPUT PATTERNS DURING RANDOM AND RHYTHMIC STIMULATION OF LOCUST THORACIC GANGLIA.
(3/32)
This paper employs new statistical techniques to further analyze the flight control system of grasshoppers. The quantitative results confirm some hypotheses which arise from previous studies of this system. After decapitation and ablation of wing proprioceptors, stimulation of the nerve cord at random intervals can elicit a coordinated response closely resembling the normal flight motor output pattern. The coordinated response begins only after many stimuli and there are usually many cycles of after-discharge. The frequency of the cyclic output is rather low and may be increased only slightly by large increases in stimulus frequency. Input from the stretch receptors is necessary to attain normal wingstroke frequency. Frequency of wingbeat rises with a time constant of about 2 seconds (or about 25 wingbeats) when stretch receptor stimulation is initiated. Frequency decay after cessation of stimulation has about the same time constant. No special phase relationship between stimulation and output is necessary for the increase in frequency or maintenance of normal pattern. When input frequency is adjusted as closely as possible to output frequency it is still not possible to force the output to maintain a particular phase with respect to the stimulation, all phase relationships still occur. In some animals all phases occurred with equal probability; in others a particular phase was preferred. When there was a strong phase preference the normal output pattern was disrupted. (+info)
LIMITATIONS ON COMPLEXITY OF RANDOM LEARNING NETWORKS.
(4/32)
Randomly connected networks can be made adaptive, and thus able to "learn." Signal-to-noise considerations are shown to limit the maximum initial complexity which can learn. A higher order of complexity may be possible in multilayered structures which learn layer-by-layer; or if learning is possible during construction. Perception-like devices would appear not to be operative if of a high order of complexity. (+info)
PASBio: predicate-argument structures for event extraction in molecular biology.
(5/32)
BACKGROUND: The exploitation of information extraction (IE), a technology aiming to provide instances of structured representations from free-form text, has been rapidly growing within the molecular biology (MB) research community to keep track of the latest results reported in literature. IE systems have traditionally used shallow syntactic patterns for matching facts in sentences but such approaches appear inadequate to achieve high accuracy in MB event extraction due to complex sentence structure. A consensus in the IE community is emerging on the necessity for exploiting deeper knowledge structures such as through the relations between a verb and its arguments shown by predicate-argument structure (PAS). PAS is of interest as structures typically correspond to events of interest and their participating entities. For this to be realized within IE a key knowledge component is the definition of PAS frames. PAS frames for non-technical domains such as newswire are already being constructed in several projects such as PropBank, VerbNet, and FrameNet. Knowledge from PAS should enable more accurate applications in several areas where sentence understanding is required like machine translation and text summarization. In this article, we explore the need to adapt PAS for the MB domain and specify PAS frames to support IE, as well as outlining the major issues that require consideration in their construction. RESULTS: We introduce PASBio by extending a model based on PropBank to the MB domain. The hypothesis we explore is that PAS holds the key for understanding relationships describing the roles of genes and gene products in mediating their biological functions. We chose predicates describing gene expression, molecular interactions and signal transduction events with the aim of covering a number of research areas in MB. Analysis was performed on sentences containing a set of verbal predicates from MEDLINE and full text journals. Results confirm the necessity to analyze PAS specifically for MB domain. CONCLUSIONS: At present PASBio contains the analyzed PAS of over 30 verbs, publicly available on the Internet for use in advanced applications. In the future we aim to expand the knowledge base to cover more verbs and the nominal form of each predicate. (+info)
A cybernetic approach to osteoporosis in anorexia nervosa.
(6/32)
A group of 25 female individuals, who had been admitted to the University Hospital with the diagnosis of anorexia nervosa (AN) 3 to 10 years before, was seen for a follow-up visit in the hospital. These women got a psychiatric exploration to detect a present eating disorder. Moreover, parameters of the muskuloskeletal interaction were determined on the non-dominant forearm. Bone mineral content (BMC) of the radius was measured by pQCT and maximal grip force was evaluated by the use of a dynamometer. Eating disorders were present in 12 females. The mean of BMC standard deviation (SD) score was significantly reduced in comparison with reference values. Furthermore, the mean of BMC SD score was also significantly lower than the mean of grip force in SD score. These results gave the suggestion that the adaptation of bone mass to biomechanical forces is disturbed in AN. The linear regression analyses between the parameters grip force and BMC were compared between the study and the reference group. The comparison delivered a significantly lower constant in the regression equation of the study group. This result can be interpreted on the background of the mechanostat theory. The affection with an eating disorder decreases the set point in the feedback loop of bone modeling. The results offer for the first time the possibility to analyse osteoporosis in anorexic females under the paradigm of muskuloskeletal interaction. (+info)
"Is Cybermedicine Killing You?"--The story of a Cochrane disaster.
(7/32)
This editorial briefly reviews the series of unfortunate events that led to the publication, dissemination, and eventual retraction of a flawed Cochrane systematic review on interactive health communication applications (IHCAs), which was widely reported in the media with headlines such as "Internet Makes Us Sick," "Knowledge May Be Hazardous to Web Consumers' Health," "Too Much Advice Can Be Bad for Your Health," "Click to Get Sick?," and even "Is Cybermedicine Killing You?". While the media attention helped to speed up the identification of errors, leading to a retraction of the review after only 13 days, a paper published in this issue of JMIR by Rada shows that the retraction, in contrast to the original review, remained largely unnoticed by the public. We discuss the three flaws of the review, which include (1) data extraction and coding errors, (2) the pooling of heterogeneous studies, and (3) a problematic and ambiguous scope and, possibly, some overlooked studies. We then discuss "retraction ethics" for researchers, editors/publishers, and journalists. Researchers and editors should, in the case of retractions, match the aggressiveness of the original dissemination campaign if errors are detected. It is argued that researchers and their organizations may have an ethical obligation to track down journalists who reported stories on the basis of a flawed study and to specifically ask them to publish an article indicating the error. Journalists should respond to errors or retractions with reports that have the same prominence as the original story. Finally, we look at some of the lessons for the Cochrane Collaboration, which include (1) improving the peer-review system by routinely sending out pre-prints to authors of the original studies, (2) avoiding downplay of the magnitude of errors if they occur, (3) addressing the usability issues of RevMan, and (4) making critical articles such as retraction notices open access. (+info)
The influence of objectives, learning experiences and examination blueprint on medical students' examination preparation.
(8/32)
BACKGROUND: The influence of intended and informal curricula on examination preparation has not been extensively studied. This study aims to firstly describe how students utilized components of intended and informal curricula to guide examination preparation, and secondly to study the relationship between examination preparation and performance. METHODS: Students received a pre-examination questionnaire to identify components from the intended curriculum (objectives and examination blueprint), and informal curriculum (content emphasised during lectures and small groups), used during examination preparation. Multiple logistic regression was used to study the relationship between these variables and student performance (above versus at or below average). RESULTS: Eighty-one students participated. There was no difference in the proportions using the examination blueprint, content emphasised during lectures, and content emphasised during small groups (87-93%) but fewer students used objectives (35%, p < 0.001). Objectives use was associated with reduced odds of above average examination performance (adjusted odds ratio 0.27 [0.07, 0.97], p = 0.04). CONCLUSION: When preparing for the renal course examination, students were influenced at least as much by the informal as the intended curriculum. Of the two intended curriculum components, the examination blueprint appeared to be more widely used than the course objectives. This decreased use of objectives on examination preparation did not appear to have a detrimental effect on student performance. (+info)