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At least 235 records · Page 13Linked to original sources
PubMed1997

Abstract genetic representation of dynamical neural networks using Kauffman networks.

Abstract (developmental) genetic representations are schemes where each genotype encodes a program for the construction of a phenotype. A new method for contriving abstract genetic representations is presented, based upon Kauffman's ideas regarding biological development [13-16]. Phenogenesis is controlled by genotype via cell replication and differentiation. Comparison is made with the earlier published methods of Gruau [9] and Kitano [18]. It is argued that greater expressive power is obtained using Kauffman networks. The new method was tested in the artificial evolution of morphology and finally successfully applied to the synthesis of structure in dynamical neural networks.

Evolution, Molecular↗
PubMed2007

Network modeling of adult neurogenesis: shifting rates of neuronal turnover optimally gears network learning according to novelty gradient.

Apoptotic and neurogenic events in the adult hippocampus are hypothesized to play a role in cognitive responses to new contexts. Corticosteroid-mediated stress responses and other neural processes invoked by substantially novel contextual changes may regulate these processes. Using elementary three-layer neural networks that learn by incremental synaptic plasticity, we explored whether the cognitive effects of differential regimens of neuronal turnover depend on the environmental context in terms of the degree of novelty in the new information to be learned. In "adult" networks that had achieved mature synaptic connectivity upon prior learning of the Roman alphabet, imposition of apoptosis/neurogenesis before learning increasingly novel information (alternate Roman < Russian < Hebrew) reveals optimality of informatic cost benefits when rates of turnover are geared in proportion to the degree of novelty. These findings predict that flexible control of rates of apoptosis-neurogenesis within plastic, mature neural systems optimizes learning attributes under varying degrees of contextual change, and that failures in this regulation may define a role for adult hippocampal neurogenesis in novelty- and stress-responsive psychiatric disorders.

Analysis of Variance↗
PubMedDate not supplied

The Ontario Health Care Evaluation Network and the Critical Care Research Network as vehicles for research transfer.

Facilitating the successful and consistent use of research results to support health care decisions is a formidable task. Barriers to effectively transferring the results of research into the decision-making process have been created between practitioners and researchers, who traditionally have worked in isolation from each other. The need for them to work cooperatively to break down these barriers is paramount as changes within the health care environment increase. The Ontario Health Care Evaluation Network (OHCEN) and the Critical Care Research Network (CCR-Net) have attempted to address these concerns by bringing together teams of researchers, practitioners, and administrative personnel with the purpose of equipping them with tools to meet oncoming health care challenges.

Computer Communication Networks↗
PubMed1999

Constructing a local district telepathology network in Japan. Diagnosis of intraoperative frozen sections via telepathology over an integrated service digital network and the National Television Standard Committee System.

OBJECTIVE: To construct a local telepathology network between the Department of Pathology, Tohoku University Hospital, and Koritu Kesennuma Hospital, about 150 km away. STUDY DESIGN: Tohoku University Hospital is connected with Koritu Kesennuma Hospital by an integrated service digital network for telepathology using the National Television Standard Committee system. The cases submitted for telepathology were limited to those in which a rapid intraoperative diagnosis was made on frozen sections. RESULTS: At this writing, more than 200 cases were diagnosed during a period of 2.5 years. The cases submitted increased with time, amounting to 150 in 1996. In some cases the use of telepathology proved to be fairly advantageous. For example, in one case a radical operation was avoided because of a diagnosis on intraoperative frozen sections. DISCUSSION: There are problems to be solved before telepathology becomes available for practical use: (1) misdiagnosis due to poor quality of instruments, including the transmission cable and pictures; (2) cost-benefit ratio, (3) protection of patients' privacy, and (4) overwork for pathologists. The Japanese government will officially accept telepathology as a means of medical examination in the future. Despite some problems left, telepathology is a promising technology.

Adenoma, Bile Duct↗
PubMed1999

Perfect DiViSy technology for video network in medicine (Moscow Information Network for Teleoncology).

A large telemedicine project is now under development in Moscow. The general task of the project is to link oncology research centres and hospitals meeting the project profile, and to provide on-line (using real-time video conferences) and off-line (via distributed database of medical information) information exchange. There was no existing technology available for use at the project's base which was ready to meet all requirements, so we are using specially created technology for video networks (DiViSy V.97). We suppose this technology to be more applicable for use in telemedicine networks than are business video conference technologies and classical Internet/Intranet technologies. We affirm in our conclusion that now is the time for developing special telemedicine standards, recommendations of compatibility, etc., and that we are ready to take part in this process.

Computer Communication Networks↗
PubMed1999

Development of the local medical service network system. Integration of medical service with the network system between university hospital and other medical institutions.

Although every medical institution always make efforts to provide best services for the patients, it tends to be insufficient to send the patient's information and share them with other medical institutions. It is partly because in the Japanese medical care system there is no obligation to inform patients' medical information to other medical institutions. To provide effective and cost-effective medical service, we made a local network system between university hospital and other medical institutions. The system contributes to clarify the role of medical institutions and the continuity of medical service. For the next step, we must construct the home-care information service network towards the total service for the patients.

Community Networks↗
PubMed1994

Regional health information networks: the Wisconsin Health Information Network, a case study.

It is projected that by the turn of the century, ninety percent of diagnostic procedures and seventy percent of therapeutic procedures will occur outside a hospital setting [2,3]. Additionally, according to a 1992 study by Arthur D. Little, during any given physician office visit, as much as 30 percent of the required diagnostic data and information required by the physician is unavailable [4]. Driven by ever increasing demands for convenience and accessibility, health care continues to evolve into an environment where the importance of data and its relative availability to the requester are diverging. This paper will present the concept of a regional or community health information network (RHIN or CHIN). Specifically, the Wisconsin Health Information Network (WHIN) will be used as a case study.

Computer Communication Networks↗
PubMed1992

Computer simulation of the segmental neural network generating locomotion in lamprey by using populations of network interneurons.

Realistic computer simulations of the experimentally established local spinal cord neural network generating swimming in the lamprey have been performed. Populations of network interneurons were used in which cellular properties, like cell size and membrane conductance including voltage dependent ion channels were randomly distributed around experimentally obtained mean values, as were synaptic conductances (kainate/AMPA, NMDA, glycine) and delays. This population model displayed more robust burst activity over a wider frequency range than the more simple subsample model used previously, and the pattern of interneuronal activity was appropriate. The strength of the reciprocal inhibition played a very important role in the regulation of burst frequency, and just by changing the inhibitory bias the entire physiological range could be covered. At the lower frequency range of bursting the segmental excitatory interneurons provide stability as does the activation of voltage dependent NMDA receptors. Spike frequency adaptation by means of summation of afterhyperpolarization (AHP) serves as a major burst terminating factor, and at lower rates the membrane properties conferred by the NMDA receptor activation. The lateral interneurons were not of critical importance for the burst termination. They may, however, be of particular importance for inducing a rapid burst termination during for instance steering and righting reactions. Several cellular factors combine to provide a secure and stable motor pattern in the entire frequency range.

Animals↗
PubMed2005

[The infectious disease epidemiology research network--a bridge between science and public health service. The example of the network for foodborne infections].

In order to respond to emerging food borne diseases, a new data-driven approach guided by epidemiologic and microbiologic data has been developed in Germany. An interdisciplinary network of scientists at the national, regional and local levels conducted surveillance and epidemiologic research of foodborne pathogens (Shiga toxin-producing Escherichia coli (STEC), Salmonella and Campylobacter). The objectives of the network include (1) determining incidence and distribution of STEC and Salmonella, (2) assessing the importance of typing systems for Campylobacter, (3) determining risk factors for sporadic STEC infections, (4) developing a system for detection of disperse outbreaks, including a national reference library of pulsed-field gel electrophoresis (PFGE) patterns, (5) examining risk factors for outbreaks, (6) carrying out a quantitative microbiological risk assessment for consumption of fresh chicken and (7) determining long-term sequelae of HUS patients.

Bacterial Infections↗
PubMed2006

Decreased white-matter density in a left-sided fronto-temporal network in children with developmental language disorder: evidence for anatomical anomalies in a motor-language network.

The neurophysiological and neuroanatomical foundations of developmental language disorder (DLD) are still a matter of dispute. A main argument is that children with DLD show atypical anatomical asymmetries of speech-relevant brain areas, which possibly affect efficient language processing. In contrast to previous anatomical studies in DLD children, this study employed voxel based morphometry (VBM) in order to search for brain anomalies outside the classical language areas. Children with DLD (n=21) and healthy children (n=21) matched for age, sex, hand preference, and education were studied using high-resolution MRI scans. Using a new variant of the voxel-based morphometry technique (augmented VBM), the brains of children with DLD and control children were compared with respect to white matter (WM) and grey matter (GM) differences. In addition, simple hand motor tests were used to uncover possible motor impairments in DLD children. We found decreased WM volumes in a left-hemispheric network comprising the motor cortex, the dorsal premotor cortex, the ventral premotor cortex, and the planum polare on the superior temporal gyrus. In addition, DLD children exhibited motor impairments in most of the applied motor tests. These results provide strong evidence that children with DLD have anomalous anatomy in a left-sided network comprising motor and language areas. Thus, this study supports the suggestion that motor and language functions are equally impaired because the underlying anatomical underpinnings are regionally identical.

Brain↗
PubMed1996

Risk factors for peritonitis in long-term peritoneal dialysis: the Network 9 peritonitis and catheter survival studies. Academic Subcommittee of the Steering Committee of the Network 9 Peritonitis and Catheter Survival Studies.

To determine factors involved in peritoneal dialysis-associated peritonitis and catheter loss, all point prevalent peritoneal dialysis patients in Health Care Finance Administration (HCFA) end-stage renal disease (ESRD) Network 9 were followed throughout 1991 for peritonitis events and throughout 1991 to 1992 for catheter survival. Data were collected by questionnaires compiled by the dialysis facility and validated by network staff. Peritonitis was reported 1,168 times in 729 of the 1,930 patients. By gamma-Poisson regression, a significantly increased risk for peritonitis was observed for patients with previous peritonitis, black race, and those dialyzing with standard connectors or cyclers compared with disconnect systems. Decreased risks were observed for patients with longer ESRD experience and when prophylactic antibiotics were administered before catheter insertion. Postinsertion leakage, diabetes, visual problems, previous or current immunosuppression, and physical activity were not risk factors. Infection of any kind caused the removal of 68% of the 414 catheters lost. Patients with downward-directed tunnels were less likely to experience concomitant exit site/tunnel infections associated with peritonitis. Peritonitis episodes with Staphylococcus epidermidis-like organisms were more likely to resolve with a single course of antibiotics. Perhaps because of their higher infection rate, blacks were more likely than whites to use a disconnect system. In general, the outcome of peritonitis in blacks was similar to that in whites, except that blacks were less likely to be hospitalized and were less likely to die.

Catheters, Indwelling↗
PubMed2004

[Follow-up network for newborns with a handicap risk: experience of the Pays-de-la-Loire network].

Newborns are given attentive perinatal care but the organization of further follow-up can be haphazard. The main consequences are the difficulties parents have in finding appropriate medical assistance for caring for high-risk infants and the absence of appropriate surveillance or efficient care. An inpatient-outpatient healthcare network enables early care of these infants and can reduce the consequences of neurosensorial sequelae. The overall impact of the regional perinatal care can also be evaluated. Such a network has been implemented in the Pays de Loire region in France since early 2003. In six months, among 1000 initially included infants, 500 were followed by pediatricians working in an outpatient (40%) or inpatient (60%) setting. This organization enables correction of over-centralization of neonatal care and the absence of coordination for follow up.

Child, Preschool↗
PubMed2003

Clustering gene expression pattern and extracting relationship in gene network based on artificial neural networks.

Massive datasets such as gene expression profiles are accumulating along with the development of DNA microarray technologies. In this paper, we focus on mining biological relevant information such as typical expression patterns and the interconnections of gene networks from massive datasets. At first, the algorithm of a self-organizing map (SOM) was used to cluster gene expression data. Then, for the typical patterns extracted by the SOM, a three-layer artificial neural network (ANN) model was used to extract the relationships between the expression patterns. In order to evaluate the clustering analysis based on the SOM, biological and statistical indices were introduced. To validate the efficiency of the scheme proposed for extracting the relationships between the expression patterns with the ANN, a test dataset was created and used for the test. Finally, the interconnections of a typical pattern of early G1, late G1, S, G2, and M phases in a yeast cell cycle were extracted and visualized.

Journal Article↗
PubMed2003

Reverse engineering of genetic networks with Bayesian networks.

This paper provides a brief introduction to learning Bayesian networks from gene-expression data. The method is contrasted with other approaches to the reverse engineering of biochemical networks, and the Bayesian learning paradigm is briefly described. The article demonstrates an application to a simple synthetic toy problem and evaluates the inference performance in terms of ROC (receiver operator characteristic) curves.

Bayes Theorem↗
PubMed2002

Using network variation in practice: identification of support network type.

This paper evaluates the use of a support network measurement instrument (PANT) in social work practice, focusing primarily on a study of the introduction and use of the instrument with social work teams. The paper describes practitioners' responses during the training period and during the initial phases of using the instrument in practice. The findings show how growth in familiarity with the new tool and support from managers overcame early resistance and contributed to both practitioners' confidence and understanding of the situations of older people. It allowed them to tailor interventions appropriately. It also contributed to understanding of differences between teams in the area and made it possible to create area profiles of older service users, their carers and their needs. The importance of network type for prediction of outcomes is stressed.

Aged↗
PubMed2006

Towards an integrated protein-protein interaction network: a relational Markov network approach.

Protein-protein interactions play a major role in most cellular processes. Thus, the challenge of identifying the full repertoire of interacting proteins in the cell is of great importance and has been addressed both experimentally and computationally. Today, large scale experimental studies of protein interactions, while partial and noisy, allow us to characterize properties of interacting proteins and develop predictive algorithms. Most existing algorithms, however, ignore possible dependencies between interacting pairs and predict them independently of one another. In this study, we present a computational approach that overcomes this drawback by predicting protein-protein interactions simultaneously. In addition, our approach allows us to integrate various protein attributes and explicitly account for uncertainty of assay measurements. Using the language of relational Markov networks, we build a unified probabilistic model that includes all of these elements. We show how we can learn our model properties and then use it to predict all unobserved interactions simultaneously. Our results show that by modeling dependencies between interactions, as well as by taking into account protein attributes and measurement noise, we achieve a more accurate description of the protein interaction network. Furthermore, our approach allows us to gain new insights into the properties of interacting proteins.

Algorithms↗
PubMed2005

Least absolute regression network analysis of the murine osteoblast differentiation network.

MOTIVATION: We propose a reverse engineering scheme to discover genetic regulation from genome-wide transcription data that monitors the dynamic transcriptional response after a change in cellular environment. The interaction network is estimated by solving a linear model using simultaneous shrinking of the least absolute weights and the prediction error. RESULTS: The proposed scheme has been applied to the murine C2C12 cell-line stimulated to undergo osteoblast differentiation. Results show that our method discovers genetic interactions that display significant enrichment of co-citation in literature. More detailed study showed that the inferred network exhibits properties and hypotheses that are consistent with current biological knowledge.

Animals↗