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Approach Makes (approach + make)
Selected AbstractsA generalized conditional intensity measure approach and holistic ground-motion selectionEARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 12 2010Brendon A. Bradley Abstract A generalized conditional intensity measure (GCIM) approach is proposed for use in the holistic selection of ground motions for any form of seismic response analysis. The essence of the method is the construction of the multivariate distribution of any set of ground-motion intensity measures conditioned on the occurrence of a specific ground-motion intensity measure (commonly obtained from probabilistic seismic hazard analysis). The approach therefore allows any number of ground-motion intensity measures identified as important in a particular seismic response problem to be considered. A holistic method of ground-motion selection is also proposed based on the statistical comparison, for each intensity measure, of the empirical distribution of the ground-motion suite with the ,target' GCIM distribution. A simple procedure to estimate the magnitude of potential bias in the results of seismic response analyses when the ground-motion suite does not conform to the GCIM distribution is also demonstrated. The combination of these three features of the approach make it entirely holistic in that: any level of complexity in ground-motion selection for any seismic response analysis can be exercised; users explicitly understand the simplifications made in the selected suite of ground motions; and an approximate estimate of any bias associated with such simplifications is obtained. Copyright © 2010 John Wiley & Sons, Ltd. [source] Climatic influences and anthropogenic stressors: an integrated framework for streamflow management in Mediterranean-climate California, U.S.A.FRESHWATER BIOLOGY, Issue 2010THEODORE E. GRANTHAM Summary 1. In Mediterranean and other water-stressed climates, water management is critical to the conservation of freshwater ecosystems. To secure and maintain water allocations for the environment, integrated water management approaches are needed that consider ecosystem flow requirements, patterns of human water demands and the temporal and spatial dynamics of water availability. 2. Human settlements in Mediterranean climates have constructed water storage and conveyance projects at a scale and level of complexity far exceeding those in other, less seasonal climates. As a result, multiple ecological stressors associated with natural periods of flooding and drying are compounded by anthropogenic impacts resulting from water infrastructure development. 3. Despite substantial investments in freshwater ecosystem conservation, particularly in California, U.S.A., success has been limited because the scales at which river management and restoration are implemented are often discordant with the temporal and spatial scales at which ecosystem processes operate. Often, there is also strong social and political resistance to restricting water allocation to existing consumptive uses for environmental protection purposes. Furthermore, institutions rarely have the capacity to develop and implement integrated management programmes needed for freshwater ecosystem conservation. 4. We propose an integrated framework for streamflow management that explicitly considers the temporal and spatial dynamics of water supply and needs of both human and natural systems. This approach makes it possible to assess the effects of alternative management strategies to human water security and ecosystem conditions and facilitates integrated decision-making by water management institutions. 5. We illustrate the framework by applying a GIS-based hydrologic model in a Mediterranean-climate watershed in Sonoma County, California, U.S.A. The model is designed to assess the hydrologic impacts of multiple water users distributed throughout a stream network. We analyse the effects of vineyard water management on environmental flows to (i) evaluate streamflow impacts from small storage ponds designed to meet human water demands and reduce summer diversions, (ii) prioritise the placement of storage ponds to meet human water needs while optimising environmental flow benefits and (iii) examine the environmental and social consequences of flow management policies designed to regulate the timing of diversions to protect ecosystem functions. 6. Thematic implications: spatially explicit models that represent anthropogenic stressors (e.g. water diversions) and environmental flow needs are required to address persistent and growing threats to freshwater biodiversity. A coupled human,natural system approach to water management is particularly useful in Mediterranean climates, characterised by severe competition for water resources and high spatial and temporal variability in flow regimes. However, lessons learned from our analyses are applicable to other highly seasonal systems and those that are expected to have increased precipitation variability resulting from climate change. [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] Applying marketing channel theory to food marketing in developing countries: Vertical disintegration model for horticultural marketing channels in kenyaAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 2 2001Tjalling Dijkstra This article shows that marketing channel theory, which has been extensively applied in developed countries, can also be of great value to the developing world. Notably, the channel approach makes it possible to explain the number of trade levels observed in food marketing systems. We propose here a vertical disintegration model for horticultural marketing channels in Kenya. It contains one dependent variable (the degree of vertical disintegration of a channel) and five independent variables (the population size of the market center served by the channel, the population density of the rural hinterland of that market center, the transport time from farm to market center, the turnover of the retailer involved, and the keeping quality of the commodity traded). Binomial and multinomial logit analyses show that the probability of encountering a more disintegrated horticultural marketing channel increases when the market center has more inhabitants, when the center's rural hinterland is more densely populated, and when the transport to the center takes more time. The probability of encountering a less disintegrated channel increases when the retailer in the channel has a larger turnover and when the traded commodity is a leafy vegetable. [EconLit classification: L190 market structure) © 2001 John Wiley & Sons, Inc. [source] Equity in Regional Service ProvisionJOURNAL OF REGIONAL SCIENCE, Issue 4 2001Alan T. Murray Most transportation agencies stipulate that an important planning goal is to provide equitable and just public transport services. However, who is to be served and the type of service that should be provided has been ambiguous. This paper develops a methodology for examining equity in the provision of public transportation services. An approach for identifying areas in need of public transport is developed based upon the use of socio-demographic and economic information. Public transport need is then related to levels of access to service. This approach makes it possible to establish the degree to which public transport services may be considered equitable in relation to need and suitable access. A detailed analysis of the southeast Queensland region of Australia illustrates how this approach may be used to inform public transport decision making. [source] Assessing the trade-offs between crossover and parallel group designs in sleep researchJOURNAL OF SLEEP RESEARCH, Issue 4 2006CHARLES C. BERRY Summary Sleep researchers invariably struggle with decisions regarding the optimal design for their studies. Whether such studies involve treatment for insomnia, obstructive sleep apnea, or any other sleep disorder, questions arise regarding the respective trade-offs between a parallel group and a crossover design. This study analyzed the variance structure of commonly measured polysomnographic variables in an effort to describe the statistical impact of these alternate designs. The study examined the effects of opioids on sleep and employed multiple crossovers between placebo, MS-contin, and methadone using a double-blind, randomized crossover design. Thirty-seven healthy subjects were studied. Four of the subjects were unable to complete the protocol for a variety of reasons, and polysomnogram data was unavailable for one subject. Data from 37 subjects provide the basis for this analysis. Despite dropouts, the crossover study was approximately four times as efficient as the parallel group design in terms of being able to recognize differences in deep sleep across these conditions. Other polysomnographic variables also favored the crossover design to varying extents. Despite the operational complexity of a crossover design, the statistical efficiency of this approach makes it a preferable approach for designing intervention studies in sleep research. [source] A combination of neutral loss and targeted product ion scanning with two enzymatic digestions facilitates the comprehensive mapping of phosphorylation sitesPROTEINS: STRUCTURE, FUNCTION AND BIOINFORMATICS, Issue 15 2007Juan Casado-Vela Abstract We propose here a new strategy for the exhaustive mapping of phosphorylation sites in the Xenopus laevis Cdc25 phosphatase, which regulates cell cycle progression in eukaryotic cells. Two different MS analyses in a linear IT were used to identify the phosphorylated residues. First, a data-dependent neutral loss (DDNL) analysis triggered the fragmentation of peptides that show enhanced neutral loss of phosphoric acid. Second, a targeted product ion scanning (TPIS) mass analysis was carried out in which MS2 events are triggered for specific m/z values. Full coverage of the protein sequence was obtained by combining the two analyses with two enzymatic digestions, trypsin and chymotrypsin, yielding a comprehensive map of the phosphorylation sites. Previous reports have shown Cdc25C to be phosphorylated by Cdc2,cyclin B at four residues (Thr48, Thr67, Thr138 and Ser205). By using this combination of scan modes, we have identified four additional phosphorylation sites (Thr86, Ser99, Thr112 and Ser163) in a recombinant Cdc25C protein containing 198 residues of the NH2 -terminal noncatalytic domain. The sensitivity of this combined approach makes it extremely useful for the comprehensive characterization of phosphorylation sites, virtually permitting complete coverage of the protein sequence with peptides within the mass detection range of the linear IT. [source] | ||||||||||