6,523 research outputs found
GeoZui3D: Data Fusion for Interpreting Oceanographic Data
GeoZui3D stands for Geographic Zooming User Interface. It is a new visualization software system designed for interpreting multiple sources of 3D data. The system supports gridded terrain models, triangular meshes, curtain plots, and a number of other display objects. A novel center of workspace interaction method unifies a number of aspects of the interface. It creates a simple viewpoint control method, it helps link multiple views, and is ideal for stereoscopic viewing. GeoZui3D has a number of features to support real-time input. Through a CORBA interface external entities can influence the position and state of objects in the display. Extra windows can be attached to moving objects allowing for their position and data to be monitored. We describe the application of this system for heterogeneous data fusion, for multibeam QC and for ROV/AUV monitoring
Learning transcriptional regulatory networks from high throughput gene expression data using continuous three-way mutual information
<p>Abstract</p> <p>Background</p> <p>Probability based statistical learning methods such as mutual information and Bayesian networks have emerged as a major category of tools for reverse engineering mechanistic relationships from quantitative biological data. In this work we introduce a new statistical learning strategy, MI3 that addresses three common issues in previous methods simultaneously: (1) handling of continuous variables, (2) detection of more complex three-way relationships and (3) better differentiation of causal versus confounding relationships. With these improvements, we provide a more realistic representation of the underlying biological system.</p> <p>Results</p> <p>We test the MI3 algorithm using both synthetic and experimental data. In the synthetic data experiment, MI3 achieved an absolute sensitivity/precision of 0.77/0.83 and a relative sensitivity/precision both of 0.99. In addition, MI3 significantly outperformed the control methods, including Bayesian networks, classical two-way mutual information and a discrete version of MI3. We then used MI3 and control methods to infer a regulatory network centered at the MYC transcription factor from a published microarray dataset. Models selected by MI3 were numerically and biologically distinct from those selected by control methods. Unlike control methods, MI3 effectively differentiated true causal models from confounding models. MI3 recovered major MYC cofactors, and revealed major mechanisms involved in MYC dependent transcriptional regulation, which are strongly supported by literature. The MI3 network showed that limited sets of regulatory mechanisms are employed repeatedly to control the expression of large number of genes.</p> <p>Conclusion</p> <p>Overall, our work demonstrates that MI3 outperforms the frequently used control methods, and provides a powerful method for inferring mechanistic relationships underlying biological and other complex systems. The MI3 method is implemented in R in the "mi3" package, available under the GNU GPL from <url>http://sysbio.engin.umich.edu/~luow/downloads.php</url> and from the R package archive CRAN.</p
Species Trees from Highly Incongruent Gene Trees in Rice
Several methods have recently been developed to infer multilocus phylogenies by incorporating information from topological incongruence of the individual genes. In this study, we investigate 2 such methods, Bayesian concordance analysis and Bayesian estimation of species trees. Our test data are a collection of genes from cultivated rice (genus Oryza) and the most closely related wild species, generated using a high-throughput sequencing protocol and bioinformatics pipeline. Trees inferred from independent genes display levels of topological incongruence that far exceed that seen in previous data sets analyzed with these species tree methods. We identify differences in phylogenetic results between inference methods that incorporate gene tree incongruence. Finally, we discuss the challenges of scaling these analyses for data sets with thousands of gene trees and extensive levels of missing data
Condensation of microturbulence-generated shear flows into global modes
In full flux-surface computer studies of tokamak edge turbulence, a spectrum
of shear flows is found to control the turbulence level and not just the
conventional (0,0)-mode flows. Flux tube domains too small for the large
poloidal scale lengths of the continuous spectrum tend to overestimate the
flows, and thus underestimate the transport. It is shown analytically and
numerically that under certain conditions dominant (0,0)-mode flows independent
of the domain size develop, essentially through Bose-Einstein condensation of
the shear flows.Comment: 5 pages, 4 figure
Searching for Invisible and Almost Invisible Particles at e^+e^- Colliders
We explore the techniques, cross sections and expected signal significance
for detecting invisible and almost invisible particles at LEP2 and the NLC by
means of a hard photon tag. Examples from supersymmetry include the lightest
chargino and second lightest neutralino when their masses are nearly the same
as that of the lightest neutralino (the LSP), and invisibly decaying
sneutrinos. The importance of particular features of the detectors is
discussed, instrumentation for vetoing a fast e^+ or e^- in the beam hole being
especially crucial.Comment: 11 pages, 2 figures, latex, corrections (as outlined in recent
Addendum [hep-ph/9902309]) to the treatment of the decay of the lightest
chargino to the lightest neutralino, when they are closely degenerate in
mass, are implemented, and the associated minor changes in phenomenology are
incorporate
Cognitive representations of disability behaviours in people with mobility limitations : consistency with theoretical constructs
Disability is conceptualised as behaviour by psychological theory and as a result of bodily impairment by medical models. However, how people with disabilities conceptualise those disabilities is unclear. The purpose of this study was to examine disability representations in people with mobility disabilities. Thirteen people with mobility disabilities completed personal repertory grids (using the method of triads) applied to activities used to measure disabilities. Ten judges with expertise in health psychology then examined the correspondence between the elicited disability constructs and psychological and medical models of disability. Participants with mobility disabilities generated 73 personal constructs ofdisability. These constructs were judged consistent with the content of two psychological models, namely the theory of planned behaviour and social cognitive theory and with the main medical model of disability, the International Classification of Functioning Disability and Health.Individuals with activity limitations conceptualise activities in a manner that is compatible with both psychological and medical models. This ensures adequate communication in contexts where the medical model is relevant, e.g. clinical contexts, as well as in everyday conversation about activities and behaviours. Finally, integrated models of disability may be of value for theory driven interdisciplinary approaches to disability and rehabilitation
Dense, low-power sensor network for three-dimensional thermal characterization of large-scale atria spaces
We describe the design and implementation of a dense, low-power wireless sensor network for fine-grained three-dimensional thermal characterization of a large open indoor space. To better understand the airflow dynamics and ensuing energy efficiency potential of this type of modern architectural design, we developed a sustainable wireless mesh network consisting of 50 sensors hung on an array of thin cables in a 210 m[superscript 2], 14.2 m tall atrium for real-time temperature and humidity monitoring. The goal is to create compact wireless measurement sensor blocks for dense coverage in the building. We demonstrate the implementation through a preliminary analysis, which includes the evaluation of temperature distribution discrepancies with computer-simulated results and data taken during natural ventilation to illustrate the nontrivial, well-mixed temperatures observed during the studies.Massachusetts Institute of Technology. Media LaboratorySchneider Electric (Firm
Neuropeptide Y concentrations in cerebrospinal fluid are unchanged in obesity
Neuropeptide Y (NPy) is a potent centrally acting appetite-stimulating peptide implicated in the regulation of energy balance. It induces hyperphagia and obesity when injected into the rat hypothalamus. Hypothalamic NPY and NPY mRNA levels are increased in spontaneously obese rats, suggesting that it may be involved in causing obesity in rodents. It is not known whether NPY has a role in the pathogenesis of obesity in man. NPY is found in human cerebrospinal fluid (CSF) and we have therefore compared CSF NPY levels in normal obese and non-obese individuals to determine whether NPY concentrations might be increased in obesity.
We studied 25 clinically normal subjects (age 67 ± 5 years. male 11. female 14) undergoing spinal anaesthesia. None had any significant illness. Samples of 1 ml were freeze-dried and reconstituted to 100 ul and 35ul aliquots were assayed for NPY using an in-house RIA. CSF NPY levels were not correlated with body mass index (BMI) (r=O.088. p=O.673) and there were no differences in NPY concentrations between groups of subjects stratified for BMI: BMI 25 (n=ll), 702 ± 55 fmol/ml (differences between all groups. p>0l).
CSF NPY levels are therefore not increased in human obesity. NPY is found in many brain regions outside the hypothalamic appetite-regulating nuclei, which could contribute to CSF levels. This negative observation does not therefore exclude a role of the peptide, acting specifically in the hypothalamus, in contributing to human obesity
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