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Neural networks as models of psychopathology.

Neural network modeling is situated between neurobiology, cognitive science, and neuropsychology. The structural and functional resemblance with biological computation has made artificial neural networks (ANN) useful for exploring the relationship between neurobiology and computational performance, i.e., cognition and behavior. This review provides an introduction to the theory of ANN and how they have linked theories from neurobiology and psychopathology in schizophrenia, affective disorders, and dementia.

Humans↗

Preservation activities and needs in U.S. biomedical libraries: a status report.

A national sample of health sciences and other types of libraries having significant holdings of biomedical literature was studied to determine the status of library preservation programs. Findings pertaining to 134 basic health sciences libraries and to ninety-seven resource libraries in the Regional Medical Library Program network are reported and discussed. Basic health sciences libraries participating in the study were primarily hospital libraries; resource libraries were primarily academic health sciences center libraries. Findings include information on topics perceived to be of greatest need for staff training and for informational or educational materials; on levels of preservation activity, staffing, and funding; and on capabilities for participating in a national cooperative preservation program. Efforts to identify general and special biomedical collections of potential importance to a national preservation program met with limited success.

Corrosion↗

Typologies of attentional networks.

Attention is a central theme in cognitive science - it exemplifies the links between the brain and behaviour, and binds psychology to the techniques of neuroscience. A visionary model suggested by Michael Posner described attention as a set of independent control networks. This challenged the previously held view of attention as a uniform concept. The idea that disparate attentional networks correlate with discrete neural circuitry and can be influenced by focal brain injuries, mental state and specific drugs has since been supported by converging data from several modern methodologies. Given the recent explosion in empirical data, attentional typologies provide powerful conceptual tools with which to contextualize and integrate these findings.

Attention↗

Practice brief. Securing wireless technology for healthcare.

Wireless networking can be a very complex science, requiring an understanding of physics and the electromagnetic spectrum. While the radio theory behind the technology can be challenging, a basic understanding of wireless networking can be sufficient for small-scale deployment. Numerous security mechanisms are available to wireless technologies, making it practical, scalable, and affordable for healthcare organizations. The decision on the selected security model should take into account the needs for additional server hardware and administrative costs. Where wide area network connections exist between cooperative organizations, deployment of a distributed security model can be considered to reduce administrative overhead. The wireless approach chosen should be dynamic and concentrate on the organization's specific environmental needs. Aspects of organizational mission, operations, service level, and budget allotment as well as an organization's risk tolerance are all part of the balance in the decision to deploy wireless technology.

Computer Communication Networks↗

The structure of scientific collaboration networks.

The structure of scientific collaboration networks is investigated. Two scientists are considered connected if they have authored a paper together and explicit networks of such connections are constructed by using data drawn from a number of databases, including MEDLINE (biomedical research), the Los Alamos e-Print Archive (physics), and NCSTRL (computer science). I show that these collaboration networks form "small worlds," in which randomly chosen pairs of scientists are typically separated by only a short path of intermediate acquaintances. I further give results for mean and distribution of numbers of collaborators of authors, demonstrate the presence of clustering in the networks, and highlight a number of apparent differences in the patterns of collaboration between the fields studied.

Authorship↗

Tracking evolving communities in large linked networks.

We are interested in tracking changes in large-scale data by periodically creating an agglomerative clustering and examining the evolution of clusters (communities) over time. We examine a large real-world data set: the NEC CiteSeer database, a linked network of >250,000 papers. Tracking changes over time requires a clustering algorithm that produces clusters stable under small perturbations of the input data. However, small perturbations of the CiteSeer data lead to significant changes to most of the clusters. One reason for this is that the order in which papers within communities are combined is somewhat arbitrary. However, certain subsets of papers, called natural communities, correspond to real structure in the CiteSeer database and thus appear in any clustering. By identifying the subset of clusters that remain stable under multiple clustering runs, we get the set of natural communities that we can track over time. We demonstrate that such natural communities allow us to identify emerging communities and track temporal changes in the underlying structure of our network data.

Cluster Analysis↗

OAFP starts practice-based resource/research network.

The Oklahoma Academy of Family Physicians, in collaboration with the University of Oklahoma Health Sciences Center, has established a primary care practice-based research network with thirteen family practice offices currently participating. The practices are connected to each other and to the Health Sciences Center campuses in Oklahoma City and Tulsa by electronic mail and have begun their first research project involving the diagnosis and treatment of brown recluse spider bites in the primary care setting.

Computer Communication Networks↗

Network thinking in ecology and evolution.

Although pairwise interactions have always had a key role in ecology and evolutionary biology, the recent increase in the amount and availability of biological data has placed a new focus on the complex networks embedded in biological systems. The increased availability of computational tools to store and retrieve biological data has facilitated wide access to these data, not just by biologists but also by specialists from the social sciences, computer science, physics and mathematics. This fusion of interests has led to a burst of research on the properties and consequences of network structure in biological systems. Although traditional measures of network structure and function have started us off on the right foot, an important next step is to create biologically realistic models of network formation, evolution, and function. Here, we review recent applications of network thinking to the evolution of networks at the gene and protein level and to the dynamics and stability of communities. These studies have provided new insights into the organization and function of biological systems by applying existing techniques of network analysis. The current challenge is to recognize the commonalities in evolutionary and ecological applications of network thinking to create a predictive science of biological networks.

Journal Article↗

Molecular networks as a sub-neural factor of neural networks.

We describe a new approach in the research of neural networks. This research is based on molecular networks in the neuron. If we use molecular networks as a sub-neuron factor of neural networks, it is a more realistic approach than today's concepts in this new computer technology field, because the artificial neural activity profile is similar to the profile of the action potential in the natural neuron. The molecular networks approach can be used in three technologies: neurocomputer, neurochip and molecular chip. This means that molecular networks open new fields of science and engineering called molecular-like machines and molecular machines.

Cytoskeleton↗

OpenSim: A Flexible Distributed Neural Network Simulator with Automatic Interactive Graphics.

An object-oriented simulator called OpenSim is presented that achieves a high degree of flexibility by relying on a small set of building blocks. The state variables and algorithms put in this framework can easily be accessed through a command shell. This allows one to distribute a large-scale simulation over several workstations and to generate the interactive graphics automatically. OpenSim opens new possibilities for cooperation among Neural Network researchers. Copyright 1997 Elsevier Science Ltd.

Journal Article↗

Essentialism and selectionism in cognitive science and behavior analysis.

Contingencies of selection, be they phylogenetic or ontogenetic, merely set boundaries on units; they do not provide blueprints. Thus, variability is fundamental to all products of selection. Skinner, by characterizing the units of analysis in behavior as generic in nature, established his science squarely within the selectionist paradigm, thereby avoiding the tendency, common throughout psychology, to slip into essentialist analyses. The distinction between essentialism and selectionism is refined in this article, and prominent examples of essentialism in linguistics, theories of memory, theories of representation, associationism, and even in behavior analysis are identified. Recent trends in cognitive science--specifically, research on adaptive networks--is amenable to a selectionist interpretation, suggesting the possibility of future fruitful interactions with behavior analysis.

Behaviorism↗

Chemo/bio-sensor networks.

The concept of wireless sensor networks conjures up images of a world of ubiquitous sensing, but it requires a massive increase in the number of sensors available. Although there has been considerable activity in transducer-based 'sensor nets', there have been virtually no corresponding deployments of chemical- or biological-sensing networks - considerable advances in materials science are needed before these can be used on a large scale.

Journal Article↗

Coordinate contribution of lipid oxidation and Maillard reaction to the nonenzymatic food browning.

Lipid oxidation and the Maillard reaction are probably the two most important reactions in Food Science. Both include a whole network of different reactions in which an extraordinary complex mixture of compounds are obtained in very different amounts and produce important changes in food flavor, color, texture, and nutritional value, with positive and negative consequences. This article analyzes the interactions between both reactions, with special emphasis in nonenzymatic browning development, by discussing the influence of lipid oxidation products in the Maillard pathway and vice versa, as well as the existence of common intermediates and polymerization mechanisms in both reactions. The existing data suggest that both reactions are so interrelated that they should be considered simultaneously to understand the products of the Maillard reaction in the presence of lipids and vice versa, and should be included in one general pathway that can be initiated by both lipids and carbohydrates.

Humans↗

Making sense of the metabolome using evolutionary computation: seeing the wood with the trees.

One should perhaps start off by asking the question, 'But what wood is it we want to see?' There are so many trees that make up the wood; within a post-genomics context, genes, transcripts, proteins, and metabolites are the more tangible ones. Rather than studying these components in isolation, a more holistic approach is to unravel the interactions between the myriad of subcellular components and this is vital to systems biology. Moreover, this will help define the phenotype of the organism under investigation. Metabolomics is complementary to transcriptomics and proteomics, and despite the immense metabolite diversity observed in plants, metabolomics has been embraced by the plant community and in particular for studying metabolic networks. Whilst post-genomic science is producing vast data torrents, it is well known that data do not equal knowledge and so the extraction of the most meaningful parts of these data is key to the generation of useful new knowledge. A metabolomics experiment is guaranteed to generate thousands of data points (e.g. samples multiplied by the levels of particular metabolites) of which only a handful might be needed to describe the problem adequately. Evolutionary computational-based methods such as genetic algorithms and genetic programming are ideal strategies for mining such high-dimensional data to generate useful relationships, rules, and predictions. This article describes these techniques and highlights their usefulness within metabolomics.

Algorithms↗

Implications of planning for regional libraries: our underlying philosophy.

The National Library of Medicine Extramural Program in administering the Medical Library Assistance Act of 1965 has developed the following specific program objectives: provide financial assistance for improving biomedical libraries; encourage and assist the establishment and functioning of a responsive national biomedical information network by strengthening present biomedical libraries and their interlibrary relationships; and assure that the biomedical library network is linked to related science information systems. The ultimate goal is to develop the role of the library as a full learning resource center for education, research, and service. The regional library program aims to augment present capability of existing medical libraries so that information can be made available more extensively and more rapidly. Comprehensive and thorough advanced planning is a basic element in the development of regional medical libraries.

Libraries, Medical↗

Science fiction becomes reality with M technologies.

Sophisticated data management--the ability to share information across geographical and technical boundaries via heterogeneous networks with seamless interoperability--was the stuff of science fiction just a few years ago. It is now a reality with M. Thomas Salander, vice chair of the M Technology Association and chairman of the MUMPS Development Committee, sets the scene and shows the way.

Computer Communication Networks↗

Activation of pmar1 controls specification of micromeres in the sea urchin embryo.

pmar1 is a transcription factor in the paired class homeodomain family that was identified and found to be transcribed in micromeres beginning at the fourth cleavage of sea urchin development [Dev. Biol. 246 (2002), 209]. Based on in situ data, molecular perturbation studies, and QPCR data, the recently published gene regulatory network (GRN) model for endomesoderm specification [Science 295 (2002) 1669; Dev. Biol. 246 (2002), 162] places pmar1 early in the micromere specification pathway, and upstream of two important micromere induction signals. The goal of this study was to test these three predictions of the network model. A series of embryo chimeras were produced in which pmar1 activity was perturbed in one cell that was transplanted to control hosts. At the fourth cleavage, micromeres bearing altered pmar1 activity were combined with a normal micromereless host embryo. If beta-catenin signaling is blocked, the micromeres remain unspecified and are unable to signal to the host cells. When such beta-catenin-blocked micromeres also express Pmar1, all observed micromere functions are rescued. The rescue includes expression of the primary mesenchyme cell (PMC) differentiation program, expression and execution of the Delta signal to induce secondary mesoderm cell (SMC) specification in macromere progeny, and expression of the early endomesoderm induction signal necessary for full specification of the endoderm. Additionally, Pmar1 expressed mosaically from inserted DNA constructs causes induction of ectopic Endo 16 in adjacent cells, demonstrating further that Pmar1 controls expression of the early endomesoderm induction signal. Based on these experiments, Pmar1 is an important transcription factor necessary for initiating the micromere specification program and for the expression of two inductive signals produced by micromeres. Each of the tests we describe supports the placement and function of Pmar1 in the endomesoderm GRN model.

Animals↗