University of Georgia

About: University of Georgia is a education organization based out in Athens, Georgia, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 41934 authors who have published 93622 publications receiving 3713212 citations. The organization is also known as: UGA & Franklin College.

Riparian plant litter quality increases with latitude

Abstract: Plant litter represents a major basal resource in streams, where its decomposition is partly regulated by litter traits. Litter-trait variation may determine the latitudinal gradient in decomposition in streams, which is mainly microbial in the tropics and detritivore-mediated at high latitudes. However, this hypothesis remains untested, as we lack information on large-scale trait variation for riparian litter. Variation cannot easily be inferred from existing leaf-trait databases, since nutrient resorption can cause traits of litter and green leaves to diverge. Here we present the first global-scale assessment of riparian litter quality by determining latitudinal variation (spanning 107°) in litter traits (nutrient concentrations; physical and chemical defences) of 151 species from 24 regions and their relationships with environmental factors and phylogeny. We hypothesized that litter quality would increase with latitude (despite variation within regions) and traits would be correlated to produce ‘syndromes’ resulting from phylogeny and environmental variation. We found lower litter quality and higher nitrogen:phosphorus ratios in the tropics. Traits were linked but showed no phylogenetic signal, suggesting that syndromes were environmentally determined. Poorer litter quality and greater phosphorus limitation towards the equator may restrict detritivore-mediated decomposition, contributing to the predominance of microbial decomposers in tropical streams.

OBSERVER: An Approach for Query Processing in Global Information Systems Based on Interoperation Across Pre-Existing Ontologies

Abstract: There has been an explosion in the types, availability and volume of data accessible in an information system, thanks to the World Wide Web (the Web) and related inter-networking technologies. In this environment, there is a critical need to replace or complement earlier database integration approaches and current browsing and keyword-based techniques with concept-based approaches. Ontologies are increasingly becoming accepted as an important part of any concept or semantics based solution, and there is increasing realization that any viable solution will need to support multiple ontologies that may be independently developed and managed. In particular, we consider the use of concepts from pre-existing real world domain ontologies for describing the content of the underlying data repositories. The most challenging issue in this approach is that of vocabulary sharing, which involves dealing with the use of different terms or concepts to describe similar information. In this paper, we describe the architecture, design and implementation of the OBSERVER system. Brokering across the domain ontologies is enabled by representing and utilizing interontology relationships such as (but not limited to) synonyms, hyponyms and hypernyms across terms in different ontologies. User queries are rewritten by using these relationships to obtain translations across ontologies. Well established metrics like precision and recall based on the extensions underlying the concepts are used to estimate the loss of information, if any.

The Current State of Business Intelligence

Abstract: Business intelligence (BI) is now widely used, especially in the world of practice, to describe analytic applications. BI is currently the top-most priority of many chief information officers. BI has become a strategic initiative and is now recognized by CIOs and business leaders as instrumental in driving business effectiveness and innovation. BI is a process that includes two primary activities: getting data in and getting data out. Getting data in, traditionally referred to as data warehousing, involves moving data from a set of source systems into an integrated data warehouse. Getting data in delivers limited value to an enterprise; only when users and applications access the data and use it to make decisions does the organization realize the full value from its data warehouse. Thus, getting data out receives most attention from organizations. This second activity, which is commonly referred to as BI, consists of business users and applications accessing data from the data warehouse to perform enterprise reporting, OLAP, querying, and predictive analytics.

Fluvial landscape ecology: addressing uniqueness within the river discontinuum

Abstract: SUMMARY 1. As rivers and streams are patchy and strongly hierarchical systems, a hierarchical patch dynamics perspective can be used as a framework for visualising interactions between structure and function in fluvial landscapes. The perspective is useful for addressing fundamental attributes of lotic ecosystems, such as heterogeneity, hierarchy, directionality and process feedback occurring across spatial scales and for illustrating spatio-temporal linkages between disparate concepts in lotic system ecology such as the River Continuum Concept, the Serial Discontinuity Concept, the Flood Pulse Concept and the Hyporheic Corridor Concept. 2. At coarse spatial scales, the hierarchical patch dynamics perspective describes each river network as a unique, patchy discontinuum from headwaters to mouth. The discontinuum is comprised of a longitudinal series of alternating stream segments with different geomorphological structures. Each confluence in the steam network further punctuates the discontinuum because the sudden change in stream characteristics can create a ‘gap’ in the expected pattern of downstream transitions. The discontinuum view recognises general trends in habitat characteristics along the longitudinal profile, but creates a framework for studying and understanding the ecological importance of each stream’s individual pattern of habitat transitions along longitudinal, lateral or vertical vectors at any scale. 3. Object-oriented modelling and programming techniques provide a means for developing robust, quantitative simulation models that describe the dynamic structure of patch hierarchies. Such models can simulate how the structure and function of lotic ecosystems are influenced by the landscape context of the system (the ecological conditions within which the system is set) and the metastructure (structural characteristics and juxtaposition) of finer-scale patches comprising the system. 4. A simple object-oriented, multiscale, discontinuum model of solute transformation and biological response along a stream channel illustrates how changing the branching pattern of a stream and the arrangement of its component patches along the downstream profile will result in substantial changes in predicted patterns of solute concentration and biotic community structure. 5. The importance of context, structure, and metastructure in determining lotic ecosystem function serves to underscore Hynes’ (1975) concept that ‘every stream is likely to be individual.’ Advancing the discipline of fluvial landscape ecology provides an excellent opportunity to develop general concepts and tools that address the individual character of each stream network and integrate the concept of ‘uniqueness within the river discontinuum’ into our ecological understanding of rivers and streams.