914 resultados para Local Variation Method


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This research extends a previously developed work concerning about the use of local model predictive control in mobile robots. Hence, experimental results are presented as a way to improve the methodology by considering aspects as trajectory accuracy and time performance. In this sense, the cost function and the prediction horizon are important aspects to be considered. The platformused is a differential driven robot with a free rotating wheel. The aim of the present work is to test the control method by measuring trajectory tracking accuracy and time performance. Moreover, strategies for the integration with perception system and path planning are also introduced. In this sense, monocular image data provide an occupancy grid where safety trajectories are computed by using goal attraction potential fields

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A simple method determining airborne monoethanolamine has been developed. Monoethanolamine determination has traditionally been difficult due to analytical separation problems. Even in recent sophisticated methods, this difficulty remains as the major issue often resulting in time-consuming sample preparations. Impregnated glass fiber filters were used for sampling. Desorption of monoethanolamine was followed by capillary GC analysis and nitrogen phosphorous selective detection. Separation was achieved using a specific column for monoethanolamines (35% diphenyl and 65% dimethyl polysiloxane). The internal standard was quinoline. Derivatization steps were not needed. The calibration range was 0.5-80 μg/mL with a good correlation (R(2) = 0.996). Averaged overall precisions and accuracies were 4.8% and -7.8% for intraday (n = 30), and 10.5% and -5.9% for interday (n = 72). Mean recovery from spiked filters was 92.8% for the intraday variation, and 94.1% for the interday variation. Monoethanolamine on stored spiked filters was stable for at least 4 weeks at 5°C. This newly developed method was used among professional cleaners and air concentrations (n = 4) were 0.42 and 0.17 mg/m(3) for personal and 0.23 and 0.43 mg/m(3) for stationary measurements. The monoethanolamine air concentration method described here was simple, sensitive, and convenient both in terms of sampling and analytical analysis.

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Here, we investigate the geographical constancy in the specificity level of the specialized lure-and-trap pollination antagonism involving the widespread European Arum maculatum and its associated Psychodid pollinators. Until now, studies concurred in demonstrating that one single insect species, Psychoda phalaenoides, efficiently cross-pollinated plants; researches were, however, performed locally in western Europe. In this study we characterize for the first time the flower visitors' composition at the scale of the distribution range of A. maculatum by intensively collecting plants and insects throughout the European continent. We further correlate local climatic characteristics with the community composition of visiting arthropods.Our results show that flowers are generally visited by P. phalaenoides females, but not over the whole distribution range of the plant. In some regions this fly species is less frequent or even absent and another species, Psycha grisescens, becomes the prevailing visitor. This variability is geographically structured and can be explained by climatic factors: the proportion of P. grisescens increases with higher annual precipitations and lower precipitations in the warmest trimester, two characteristics typical of the Mediterranean zone. Climate thus seems driving the specificity of this interaction, by potentially affecting the phenology of one or both interacting species, or even of volatile and heat production in the plant. This result therefore challenges the specificity of other presumably one-to-one interactions covering wide distribution ranges, and provides an example of the direct effect that the abiotic environment can have on the fate of plant-insect interactions.

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BACKGROUND: The activity of the renin-angiotensin system is usually evaluated as plasma renin activity (PRA, ngAI/ml per h) but the reproducibility of this enzymatic assay is notoriously scarce. We compared the inter and intralaboratory reproducibilities of PRA with those of a new automated chemiluminescent assay, which allows the direct quantification of immunoreactive renin [chemiluminescent immunoreactive renin (CLIR), microU/ml]. METHODS: Aliquots from six pool plasmas of patients with very low to very high PRA levels were measured in 12 centres with both the enzymatic and the direct assays. The same methods were applied to three control plasma preparations with known renin content. RESULTS: In pool plasmas, mean PRA values ranged from 0.14 +/- 0.08 to 18.9 +/- 4.1 ngAI/ml per h, whereas those of CLIR ranged from 4.2 +/- 1.7 to 436 +/- 47 microU/ml. In control plasmas, mean values of PRA and of CLIR were always within the expected range. Overall, there was a significant correlation between the two methods (r = 0.73, P < 0.01). Similar correlations were found in plasmas subdivided in those with low, intermediate and high PRA. However, the coefficients of variation among laboratories found for PRA were always higher than those of CLIR, ranging from 59.4 to 17.1% for PRA, and from 41.0 to 10.7% for CLIR (P < 0.01). Also, the mean intralaboratory variability was higher for PRA than for CLIR, being respectively, 8.5 and 4.5% (P < 0.01). CONCLUSION: The measurement of renin with the chemiluminescent method is a reliable alternative to PRA, having the advantage of a superior inter and intralaboratory reproducibility.

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Gene set enrichment (GSE) analysis is a popular framework for condensing information from gene expression profiles into a pathway or signature summary. The strengths of this approach over single gene analysis include noise and dimension reduction, as well as greater biological interpretability. As molecular profiling experiments move beyond simple case-control studies, robust and flexible GSE methodologies are needed that can model pathway activity within highly heterogeneous data sets. To address this challenge, we introduce Gene Set Variation Analysis (GSVA), a GSE method that estimates variation of pathway activity over a sample population in an unsupervised manner. We demonstrate the robustness of GSVA in a comparison with current state of the art sample-wise enrichment methods. Further, we provide examples of its utility in differential pathway activity and survival analysis. Lastly, we show how GSVA works analogously with data from both microarray and RNA-seq experiments. GSVA provides increased power to detect subtle pathway activity changes over a sample population in comparison to corresponding methods. While GSE methods are generally regarded as end points of a bioinformatic analysis, GSVA constitutes a starting point to build pathway-centric models of biology. Moreover, GSVA contributes to the current need of GSE methods for RNA-seq data. GSVA is an open source software package for R which forms part of the Bioconductor project and can be downloaded at http://www.bioconductor.org.

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Structural variation, whether it is caused by copy number variants or present in a balanced form, such as reciprocal translocations and inversions, can have a profound and dramatic effect on the expression of genes mapping within and close to the rearrangement, as well as affecting others genome wide. These effects can be caused by altering the copy number of one or more genes or regulatory elements (dosage effect) or from physical disruption of links between regulatory elements and their associated gene or genes, resulting in perturbation of expression. Similarly, large-scale structural variants can result in genome-wide expression changes by altering the positions that chromosomes occupy within the nucleus, potentially disrupting not only local cis interactions, but also trans interactions that occur throughout the genome. Structural variation is, therefore, a significant factor in the study of gene expression and is discussed here in more detail.

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Significant progress has been made with regard to the quantitative integration of geophysical and hydrological data at the local scale. However, extending the corresponding approaches to the regional scale represents a major, and as-of-yet largely unresolved, challenge. To address this problem, we have developed an upscaling procedure based on a Bayesian sequential simulation approach. This method is then applied to the stochastic integration of low-resolution, regional-scale electrical resistivity tomography (ERT) data in combination with high-resolution, local-scale downhole measurements of the hydraulic and electrical conductivities. Finally, the overall viability of this upscaling approach is tested and verified by performing and comparing flow and transport simulation through the original and the upscaled hydraulic conductivity fields. Our results indicate that the proposed procedure does indeed allow for obtaining remarkably faithful estimates of the regional-scale hydraulic conductivity structure and correspondingly reliable predictions of the transport characteristics over relatively long distances.

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En aquest document es pretén estudiar de la viabilitat econòmica de la implantació d’una planta de piròlisi per a la producció de biochar o char en un context local i comarcal. La biomassa és una font d’energia que genera uns rendiments energètics prou interesants i d’una manera respectuosa amb el medi ambient. Així doncs, la teòrica planta utilitzarà biomassa que, a traves del tractament termoquímic de la piròlisi, ens generarà uns productes que són d’utilitat per l’obtenció d’energia d’una manera respectuosa amb el medi ambient. Abans de fer l’anàlisi econòmic, hi ha una explicació extensa dels processos termoquímics, com són la piròlisi, la gasificació i la torrefacció. Posteriorment, es du a terme una revisió de l’estat actual de les tecnologies de conversió de biomassa a Catalunya i finalment es realitza un inventari i anàlisi dels usos de la biomassa a Catalunya, en el qual es parla principalment de l’estella el pèl·let, així com també de la seva producció, consum i exportació. El nostre anàlisi econòmic de la planta de processament de biomassa es durà a terme a nivell local, és a dir en un municipi, i també a nivell comarcal a Catalunya. A partir del processament de biomassa per mitja de la piròlisi, obtindrem uns productes, entre els quals el biochar, que serà un dels productes finals per poder vendre. L’altre producte serà el pèl·let de biochar, que l’obtindrem a través del procés de pel·letització. Aquest procés ens permetrà densificar el mateix biochar i obtenir-ne pèl·lets amb un poder calorífic superior, com també el seu possible preu de venda final. En aquest anàlisi econòmic plantejarem diferents escenaris tant a nivell local com comarcal, és a dir, farem variar diferents paràmetres de la planta, com poden ser els dies, les hores de treball, el sou dels treballadors, l’existència de procés de pel·letització...per veure la viabilitat del nostre projecte. Aquesta viabilitat la mesurarem amb diferents Índexs, entre els quals hi ha l’Índex de Rendibilitat, que ens determinarà si el projecte és possible si el seu valor és més gran a 1.

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The proposed Federal Highway Administration (FHWA) amendments to the Manual of Uniform Traffic Control Devices (MUTCD) will change the way local agencies manage their pavement markings and places a focus on pavement marking quality and management methods. This research effort demonstrates how a pavement marking maintenance method could be developed and used at the local agency level. The report addresses the common problems faced by agencies in achieving good pavement marking quality and provides recommendations specific towards these problems in terms of assessing pavement marking needs, selecting pavement marking materials, contracting out pavement marking services, measuring and monitoring performance, and in developing management tools to visualize pavement marking needs in a GIS format. The research includes five case studies, three counties and two cities, where retroreflectivity was measured over a spring and fall season and then mapped to evaluate pavement marking performance and needs. The research also includes over 35 field demonstrations (installation and monitoring) of both longitudinal and transverse durable markings in a variety of local agency settings all within an intense snow plow state.

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As truck traffic on Iowa secondary roads has increased, engineers have moved to concrete pavements of greater depths. Early designs included thickened edge pavements and depths of seven inches or greater. The designs typically did not have load transfer devices installed in the transverse joints and relied on aggregate interlock for this purpose. In some cases, aggregate interlock was not adequate to deal with the soils and traffic conditions and faulting of the joints has begun to appear. Engineers are now faced with the need to install or retrofit load transfer in the joints to preserve the pavements. Questions associated with this decision range from the type of dowel material to dowel diameter, spacing, number of bars, placement method, and construction techniques to be used to assure reduction or elimination of faulting. Buena Vista County constructed a dowel bar retrofit project on one mile of road. The plan called for addition of the dowels (2, 3, or 4) in the outer wheel path only and surface grinding in lieu of asphalt overlay. The project included the application of elliptical- and round-shaped dowels in a rehabilitation project. Dowel material types included conventional epoxy-coated steel and fiber-reinforced polymer (FRP). This work involved the determination of relative costs in materials to be used in this type of work and performance of FRP and elliptical-shaped steel dowels in the retrofit work. The results indicate good performance from each of the bar configurations and use the results of ride and deflection testing over the research period to project the benefits that can be gained from each configuration vs. the anticipated construction costs. The reader is cautioned that this project could not relate the number of dowels required to the level of anticipated truck traffic for other roads that might be considered.

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Simulated-annealing-based conditional simulations provide a flexible means of quantitatively integrating diverse types of subsurface data. Although such techniques are being increasingly used in hydrocarbon reservoir characterization studies, their potential in environmental, engineering and hydrological investigations is still largely unexploited. Here, we introduce a novel simulated annealing (SA) algorithm geared towards the integration of high-resolution geophysical and hydrological data which, compared to more conventional approaches, provides significant advancements in the way that large-scale structural information in the geophysical data is accounted for. Model perturbations in the annealing procedure are made by drawing from a probability distribution for the target parameter conditioned to the geophysical data. This is the only place where geophysical information is utilized in our algorithm, which is in marked contrast to other approaches where model perturbations are made through the swapping of values in the simulation grid and agreement with soft data is enforced through a correlation coefficient constraint. Another major feature of our algorithm is the way in which available geostatistical information is utilized. Instead of constraining realizations to match a parametric target covariance model over a wide range of spatial lags, we constrain the realizations only at smaller lags where the available geophysical data cannot provide enough information. Thus we allow the larger-scale subsurface features resolved by the geophysical data to have much more due control on the output realizations. Further, since the only component of the SA objective function required in our approach is a covariance constraint at small lags, our method has improved convergence and computational efficiency over more traditional methods. Here, we present the results of applying our algorithm to the integration of porosity log and tomographic crosshole georadar data to generate stochastic realizations of the local-scale porosity structure. Our procedure is first tested on a synthetic data set, and then applied to data collected at the Boise Hydrogeophysical Research Site.

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Three pavement design software packages were compared with regards to how they were different in determining design input parameters and their influences on the pavement thickness. StreetPave designs the concrete pavement thickness based on the PCA method and the equivalent asphalt pavement thickness. The WinPAS software performs both concrete and asphalt pavements following the AASHTO 1993 design method. The APAI software designs asphalt pavements based on pre-mechanistic/empirical AASHTO methodology. First, the following four critical design input parameters were identified: traffic, subgrade strength, reliability, and design life. The sensitivity analysis of these four design input parameters were performed using three pavement design software packages to identify which input parameters require the most attention during pavement design. Based on the current pavement design procedures and sensitivity analysis results, a prototype pavement design and sensitivity analysis (PD&SA) software package was developed to retrieve the pavement thickness design value for a given condition and allow a user to perform a pavement design sensitivity analysis. The prototype PD&SA software is a computer program that stores pavement design results in database that is designed for the user to input design data from the variety of design programs and query design results for given conditions. The prototype Pavement Design and Sensitivity Analysis (PA&SA) software package was developed to demonstrate the concept of retrieving the pavement design results from the database for a design sensitivity analysis. This final report does not include the prototype software which will be validated and tested during the next phase.

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The M-Coffee server is a web server that makes it possible to compute multiple sequence alignments (MSAs) by running several MSA methods and combining their output into one single model. This allows the user to simultaneously run all his methods of choice without having to arbitrarily choose one of them. The MSA is delivered along with a local estimation of its consistency with the individual MSAs it was derived from. The computation of the consensus multiple alignment is carried out using a special mode of the T-Coffee package [Notredame, Higgins and Heringa (T-Coffee: a novel method for fast and accurate multiple sequence alignment. J. Mol. Biol. 2000; 302: 205-217); Wallace, O'Sullivan, Higgins and Notredame (M-Coffee: combining multiple sequence alignment methods with T-Coffee. Nucleic Acids Res. 2006; 34: 1692-1699)] Given a set of sequences (DNA or proteins) in FASTA format, M-Coffee delivers a multiple alignment in the most common formats. M-Coffee is a freeware open source package distributed under a GPL license and it is available either as a standalone package or as a web service from www.tcoffee.org.

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24S- and 27-hydroxycholesterol are obligatory intermediates of cholesterol catabolism and play an important role in the maintenance of whole-body cholesterol homeostasis. Using an HPLC-MS method for oxysterol quantification, the distribution of esterified and unesterified oxysterols in lipoprotein subfractions as well as the influence of daytime, food intake and menstrual cycle on oxysterol concentrations were investigated in healthy volunteers. Moreover, reference intervals for 24S- and 27-hydroxycholesterol in plasma as well as the corresponding levels for 27-hydroxycholesterol in the HDL subfraction were established in 100 healthy volunteers. Both circulating oxysterols are mainly transported in association with HDL and LDL--primarily in the esterified form. No significant diurnal changes and no variations during menstrual cycle of either absolute or cholesterol-related plasma levels were detected. In contrast to 24S-hydroxycholesterol in plasma and 27-hydroxycholesterol in the HDL subfraction, the 95% reference intervals of 27-hydroxycholesterol both in plasma and the non-HDL subfraction were higher in males than in females. The concentrations of 27-hydroxycholesterol in plasma and the non-HDL subfraction showed strong positive correlations with the concentrations of cholesterol, non-HDL cholesterol and triglycerides. Our data on the lipoprotein distribution of oxysterols as well as on their intra- and inter-individual variation set the stage for future clinical studies.

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This thesis examines the local and regional scale determinants of biodiversity patterns using existing species and environmental data. The research focuses on agricultural environments that have experienced rapid declines of biodiversity during past decades. Existing digital databases provide vast opportunities for habitat mapping, predictive mapping of species occurrences and richness and understanding the speciesenvironment relationships. The applicability of these databases depends on the required accuracy and quality of the data needed to answer the landscape ecological and biogeographical questions in hand. Patterns of biodiversity arise from confounded effects of different factors, such as climate, land cover and geographical location. Complementary statistical approaches that can show the relative effects of different factors are needed in biodiversity analyses in addition to classical multivariate models. Better understanding of the key factors underlying the variation in diversity requires the analyses of multiple taxonomic groups from different perspectives, such as richness, occurrence, threat status and population trends. The geographical coincidence of species richness of different taxonomic groups can be rather limited. This implies that multiple geographical regions should be taken into account in order to preserve various groups of species. Boreal agricultural biodiversity and in particular, distribution and richness of threatened species is strongly associated with various grasslands. Further, heterogeneous agricultural landscapes characterized by moderate field size, forest patches and non-crop agricultural habitats enhance the biodiversity of rural environments. From the landscape ecological perspective, the major threats to Finnish agricultural biodiversity are the decline of connected grassland habitat networks, and general homogenization of landscape structure resulting from both intensification and marginalization of agriculture. The maintenance of key habitats, such as meadows and pastures is an essential task in conservation of agricultural biodiversity. Furthermore, a larger landscape context should be incorporated in conservation planning and decision making processes in order to respond to the needs of different species and to maintain heterogeneous rural landscapes and viable agricultural diversity in the future.