Home About us Contact
|
Home About us Contact | ||
|
|
||
Various Clusters (various + cluster)
Selected AbstractsNovel microbial diversity adherent to plant biomass in the herbivore gastrointestinal tract, as revealed by ribosomal intergenic spacer analysis and rrs gene sequencingENVIRONMENTAL MICROBIOLOGY, Issue 4 2005Ross Larue Summary It is well recognized that a dynamic biofilm develops upon plant biomass in the herbivore gastrointestinal tract, but this component of the microbiome has not previously been specifically sampled, or directly compared with the biodiversity present in the planktonic fraction of digesta. In this study, the digesta collected from four sheep fed two different diets was separated into three fractions: the planktonic phase, and the microbial populations either weakly or tightly adherent to plant biomass. The community DNA prepared from each fraction was then subjected to both ribosomal intergenic spacer analysis (RISA) and denaturing gradient gel electrophoresis (DGGE). Both types of analysis showed that dietary factors influence community structure, and that the adherent fractions produced more complex profiles. The RIS-clone libraries prepared from the planktonic and adherent populations were then subjected to restriction fragment length polymorphism (RFLP) and DNA sequence analyses, which resulted in a far greater degree of discrimination among the fractions. Although many of the sequenced clones from the adherent populations were assigned to various clusters within the low G+C Gram-positive bacteria, the clone libraries from animals consuming an all-grass diet were largely comprised of novel lineages of Clostridium, while in animals consuming the starch-containing diet, Selenomonas and Ruminococcus spp. were the dominant low G+C Gram-positive bacteria. Additionally, the libraries from hay-fed animals also contained clones most similar to asaccharolytic Clostridia, and other Gram-positive bacteria that specialize in the transformation of plant phenolic compounds and the formation of cinnamic, phenylacetic and phenylpropionic acids. These results reveal, for the first time, the phylogeny of adherent subpopulations that specialize in the transformation of plant lignins and other secondary compounds, which potentiate polysaccharide hydrolysis by other members of the biofilm. [source] Agglomeration Potential: The Spatial Scale of Industry Linkages in the Southern California EconomyGROWTH AND CHANGE, Issue 1 2008RICHARD G. FUNDERBURG ABSTRACT Targeting industry clusters for economic development has become popular despite the lack of empirical evidence about the spatial scales over which various clusters agglomerate. This paper identifies twenty manufacturing industry clusters from a principal components analysis of interindustry patterns of trade and measures the spatial employment concentration of each cluster's plants within a polycentric framework. Two to eight centers of employment concentration are detected within the Southern California region for each set of trade linkages. Our spatial half-life measure reveals that half of a cluster's employment in associated establishments is located within a typical range of eight to twelve kilometers (about 5,7.5 miles) to the nearest employment center or subcenter for the particular cluster. Furthermore, employment in seventeen of the twenty clusters is found to be more spatially concentrated than manufacturing employment as a whole, suggesting that geographic proximity is important to interindustry linkages in the Southern California economy. More important, the spatial concentration across industry clusters varies considerably within the metropolitan area, implying that economic development practitioners should consider local context and adapt industry cluster theories to the specific advantages and disadvantages of their immediate locality. [source] Diagnostic evaluation of conceptual rainfall,runoff models using temporal clusteringHYDROLOGICAL PROCESSES, Issue 20 2010N. J. de Vos Abstract Given the structural shortcomings of conceptual rainfall,runoff models and the common use of time-invariant model parameters, these parameters can be expected to represent broader aspects of the rainfall,runoff relationship than merely the static catchment characteristics that they are commonly supposed to quantify. In this article, we relax the common assumption of time-invariance of parameters, and instead seek signature information about the dynamics of model behaviour and performance. We do this by using a temporal clustering approach to identify periods of hydrological similarity, allowing the model parameters to vary over the clusters found in this manner, and calibrating these parameters simultaneously. The diagnostic information inferred from these calibration results, based on the patterns in the parameter sets of the various clusters, is used to enhance the model structure. This approach shows how diagnostic model evaluation can be used to combine information from the data and the functioning of the hydrological model in a useful manner. Copyright © 2010 John Wiley & Sons, Ltd. [source] Quality of service control in multimedia network clustersINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 8 2003Franco Davoli Abstract We introduce a control architecture in which several (independent) multimedia clusters share the same (local or metropolitan) networking resources in a controlled framework. In particular, a central entity (i.e., the Gatekeeper) harmonizes the transmission rates of the various clusters following a given sharing policy. Each cluster, in turn, adopts its own end-to-end rate control mechanism to meet the Gatekeeper's transmission rate indications. A testbed has been developed and the system has been evaluated with real experiments by using different types of transmission sources. A software architecture is also introduced and described, with particular reference to the middleware framework realized with the Jini system. Copyright © 2003 John Wiley & Sons, Ltd. [source] Clustering of variables to analyze spectral dataJOURNAL OF CHEMOMETRICS, Issue 3 2005E. Vigneau Abstract A cluster analysis of variables around latent variables is presented and applied in order to identify groups among near-infrared (NIR) spectral variables. By organizing multivariate data into a small number of clusters, each of them being represented by a component, this approach makes it possible to reduce the dimensionality of the problem. For the NIR data considered herein, it turned out that the groups of spectral variables are associated with various spectral regions. This feature can be helpful for the interpretation of the outcomes. For a predictive perspective the groups of variables can be used as blocks in multiblock partial least squares models. Alternatively the latent variables associated with the various clusters can be used as predictors. The cluster analysis procedure together with how its outcomes can be used for prediction purposes are illustrated on the basis of sensory and NIR data on green peas. Copyright © 2005 John Wiley & Sons, Ltd. [source] Community-based Participatory Research: Development of an Emergency Department,based Youth Violence Intervention Using Concept MappingACADEMIC EMERGENCY MEDICINE, Issue 8 2010Carolyn E. Snider MD, FRCPC ACADEMIC EMERGENCY MEDICINE 2010; 17:1,9 © 2010 by the Society for Academic Emergency Medicine Abstract Objectives:, Emergency departments (EDs) see a high number of youths injured by violence. In Ontario, the most common cause of injury for youths visiting EDs is assault. Secondary prevention strategies using the teachable moment (i.e., events that can lead individuals to make positive changes in their lives) are ideal for use by clinicians. An opportunity exists to take advantage of the teachable moment in the ED in an effort to prevent future occurrences of injury in at-risk youths. However, little is known about perceptions of youths, parents, and community organizations about such interventions in EDs. The aims of this study were to engage youths, parents, and frontline community workers in conceptualizing a hospital-based violence prevention intervention and to identify outcomes relevant to the community. Methods:, Concept mapping is an innovative, mixed-method research approach. It combines structured qualitative processes such as brainstorming and group sorting, with various statistical analyses such as multidimensional scaling and hierarchical clustering, to develop a conceptual framework, and allows for an objective presentation of qualitative data. Concept mapping involves multiple structured steps: 1) brainstorming, 2) sorting, 3) rating, and 4) interpretation. For this study, the first three steps occurred online, and the fourth step occurred during a community meeting. Results:, Over 90 participants were involved, including youths, parents, and community youth workers. A two-dimensional point map was created and clusters formed to create a visual display of participant ideas on an ED-based youth violence prevention intervention. Issues related to youth violence prevention that were rated of highest importance and most realistic for hospital involvement included mentorship, the development of youth support groups in the hospital, training doctors and nurses to ask questions about the violent event, and treating youth with respect. Small-group discussions on the various clusters developed job descriptions, a list of essential services, and suggestions on ways to create a more youth-friendly environment in the hospital. A large-group discussion revealed outcomes that participants felt should be measured to determine the success of an intervention program. Conclusions:, This study has been the springboard for the development of an ED-based youth violence intervention that is supported by the community and affected youth. Using information generated by youth that is grounded in their experience through participatory research methods is feasible for the development of successful and meaningful youth violence prevention interventions. [source] | ||||||||||