An adaptive sampling method for global sensitivity analysis based on least-squares support vector regression

In the field of engineering, surrogate models are commonly used for approximating the behavior of a physical phenomenon in order to reduce the computational costs. Generally, a surrogate model is created based on a set of training data, where a typical method for the statistical design is the Latin hypercube sampling (LHS). Even though a space filling distribution of the training data is reached, the sampling process takes no information on the underlying behavior of the physical phenomenon into account and new data cannot be sampled in the same distribution if the approximation quality is not sufficient. Therefore, in this study we present a novel adaptive sampling method based on a specific surrogate model, the least-squares support vector regresson. The adaptive sampling method generates training data based on the uncertainty in local prognosis capabilities of the surrogate model - areas of higher uncertainty require more sample data. The approach offers a cost efficient calculation due to the properties of the least-squares support vector regression. The opportunities of the adaptive sampling method are proven in comparison with the LHS on different analytical examples. Furthermore, the adaptive sampling method is applied to the calculation of global sensitivity values according to Sobol, where it shows faster convergence than the LHS method. With the applications in this paper it is shown that the presented adaptive sampling method improves the estimation of global sensitivity values, hence reducing the overall computational costs visibly

A thyroid hormone receptor-dependent glucocorticoid induction.

Glucocorticoid and thyroid hormones exert their effects in many body tissues by binding to their respective receptors. The search for possible cross-talking mechanisms in overlapping target cells led to the discovery of synergism between a thyroid hormone receptor-binding site and a cryptic glucocorticoid-responsive element. Glucocorticoid responsiveness could only be detected in the presence of thyroid hormone and its receptor. This synergism requires the glucocorticoid receptor (GR) DNA-binding domain and is mediated by the transactivation domains. We found that synergism also occurs when the thyroid hormone receptor is replaced by the retinoic acid receptor or the GR is replaced by the progesterone receptor. Synergism is qualitatively independent of the type of thyroid hormone receptor-binding site and promoter. In several combinations of promoter and response elements, including a retinoic acid response element, T3 induction was only seen in the presence of the cryptic glucocorticoid-responsive element, GR, and glucocorticoids

Detiding shipboard-mounted ADCP data: an analysis of model data and observations using a polynomial interpolation method

A method for determining the net non-tidal flow from shipboard-mounted acoustic Doppler current profiler (ADCP) data is applied to observations from the Gulf of the Farallones in 1991- 2. Tidal currents represent a significant portion of the total flow in the region. Both the tidal and non-tidal current fields arc characterized by spatial and temporal variability on small scales. The detiding method performs a least- squares fit to determine the spatial structure of both the amplitudes of the major tidal constituents and the magnitude of the non-tidal flow. Synthetic data is used to examine the requirements and constraints in choosing the best polynomial fitting function for each of the field's components. Arbitrarily choosing a higher-order polynomial to represent these fields may result in misrepresentation of the true flow. Results of applying this technique to vertically-averaged ADCP data from five seasonal surveys of approximately five-day duration are presented.http://archive.org/details/detidingshipboar1094542866U.S. Navy (USN) authorApproved for public release; distribution is unlimited

Deploying the WTO Agreement on Government Procurement (GPA) to Enhance Sustainability and Accelerate Climate Change Mitigation

Mitigating climate change and promoting sustainability are defining challenges of our time. Public procurement has a vital role to play in responding to the current crises. This article makes the case that the World Trade Organization’s (WTO) Agreement on Government Procurement (GPA), and specifically the Work Programme on Sustainable Procurement that has been initiated pursuant to the Agreement, can serve as important instruments to promote sustainable approaches to public procurement internationally, consistent with the goals of climate change mitigation. The Work Programme, which was established at the time of the GPA’s modernization in 2012 and on which important work has already been done but which has recently been relatively dormant, mandates the Organization’s Committee on Government Procurement to study, inter alia, “the ways in which sustainable procurement can be practiced in a manner consistent with Parties’ international trade obligations ”and to prepare a report that sets out best practices concerning relevant measures and polices. This provides an essential and attractive platform for responding to the crisis. The article sets out important related background, including with respect to: (i) a “change of mindset” with respect to environmental sustainability which is already embodied in the amended GPA text adopted in 2012; (ii) existing GPA provisions that provide windows of opportunity for the advancing of related objectives; and (iii) importantly, ongoing developments in key GPA Parties and at the international level that both: (a) point the way toward meaningful change; and (b) suggest, in our view, a need for a modest degree of international coordination to avoid conflict and ensure continuing market openness. These developments portend a rich agenda of possibilities for further discussions in the WTO Work Programme

Size-Ramsey numbers of structurally sparse graphs

Size-Ramsey numbers are a central notion in combinatorics and have been widely studied since their introduction by Erd\H{o}s, Faudree, Rousseau and Schelp in 1978. Research has mainly focused on the size-Ramsey numbers of $n$-vertex graphs with constant maximum degree $\Delta$. For example, graphs which also have constant treewidth are known to have linear size-Ramsey numbers. On the other extreme, the canonical examples of graphs of unbounded treewidth are the grid graphs, for which the best known bound has only very recently been improved from $O(n^{3/2})$ to $O(n^{5/4})$ by Conlon, Nenadov and Truji\'c. In this paper, we prove a common generalization of these results by establishing new bounds on the size-Ramsey numbers in terms of treewidth (which may grow as a function of $n$). As a special case, this yields a bound of $\tilde{O}(n^{3/2 - 1/2\Delta})$ for proper minor-closed classes of graphs. In particular, this bound applies to planar graphs, addressing a question of Wood. Our proof combines methods from structural graph theory and classic Ramsey-theoretic embedding techniques, taking advantage of the product structure exhibited by graphs with bounded treewidth.Comment: 21 page

Transcriptomic characterization of two major Fusarium resistance quantitative trait loci (QTLs), Fhb1 and Qfhs.ifa-5A, identifies novel candidate genes

Fusarium head blight, caused by Fusarium graminearum, is a devastating disease of wheat. We developed near-isogenic lines (NILs) differing in the two strongest known F. graminearum resistance quantitative trait loci (QTLs), Qfhs.ndsu-3BS (also known as resistance gene Fhb1) and Qfhs.ifa-5A, which are located on the short arm of chromosome 3B and on chromosome 5A, respectively. These NILs showing different levels of resistance were used to identify transcripts that are changed significantly in a QTL-specific manner in response to the pathogen and between mock-inoculated samples. After inoculation with F. graminearum spores, 16 transcripts showed a significantly different response for Fhb1 and 352 for Qfhs.ifa-5A. Notably, we identified a lipid transfer protein which is constitutively at least 50-fold more abundant in plants carrying the resistant allele of Qfhs.ifa-5A. In addition to this candidate gene associated with Qfhs.ifa-5A, we identified a uridine diphosphate (UDP)-glycosyltransferase gene, designated TaUGT12887, exhibiting a positive difference in response to the pathogen in lines harbouring both QTLs relative to lines carrying only the Qfhs.ifa-5A resistance allele, suggesting Fhb1 dependence of this transcript. Yet, this dependence was observed only in the NIL with already higher basal resistance. The complete cDNA of TaUGT12887 was reconstituted from available wheat genomic sequences, and a synthetic recoded gene was expressed in a toxin-sensitive strain of Saccharomyces cerevisiae. This gene conferred deoxynivalenol resistance, albeit much weaker than that observed with the previously characterized barley HvUGT13248