1,018 research outputs found

    PERFORMANCE OF RISK-INCOME MODELS OUTSIDE THE ORIGINAL DATA SET

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    Selected risk programming solutions (i.e., profit maximization, Target-MOTAD, and MOTAD) are tested in an economic environment outside the data set from which they were developed. Specifically, solutions are derived from either a longer 10-year (1965-74) or shorter 6-year estimation period (1969-74), and then, they are tested for consistent risk-income characteristics over a later 10-year period (1975-84). Risk solutions estimated from earlier periods perform well in the later test period in spite of different economic conditions between time periods. However, favorable performance may be related to the specific example used in this analysis. Further testing for other farm situations is needed before general conclusions can be reached.Risk and Uncertainty,

    INCORPORATING SAFETY-FIRST CONSTRAINTS IN LINEAR PROGRAMMING PRODUCTION MODELS

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    A recent survey indicated that many procedures view risk in a safety-first context. Traditional methods used to impose safety-first constraints in optimization models have often been difficult to implement. This is particularly true when endogenous decisions affect the distribution of the chance-constrained random variable. This paper presents a method whereby probabilistic constraints can be easily imposed upon finitely discrete random variables. The procedure uses a linear version of the lower partial moment stochastic inequality. The resulting solutions are somewhat conservative but are less so than the results using the previously published mean income-absolute deviation stochastic inequality.Production Economics, Research Methods/ Statistical Methods,

    The problem of globalization

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    There is a general consensus that the contemporary world is best under-stood through the prism of globalization. This view is shared by most social scientists, politicians, journalists, businesses, and indeed broad sectors of the general population. Opinions differ as to whether global-ization is a positive or a negative development, but there is general agreement that whatever is going on is either a symptom or a consequence of globalization. There are many good reasons for this view. The number of passengers on scheduled international flights has risen by a factor of six between 1975 and 2000. The number of international tourist arrivals rose by three and a half times during the same period. Much less happily, the number of internationally displaced refugees rose by around 50 percent in the 20 years before 2000. During the quarter of a century after 1975, the duration of international voice telephone calls rose by around 25 times. We could go on multiplying such striking figures i

    Novel method for high-throughput colony PCR screening in nanoliter-reactors

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    We introduce a technology for the rapid identification and sequencing of conserved DNA elements employing a novel suspension array based on nanoliter (nl)-reactors made from alginate. The reactors have a volume of 35 nl and serve as reaction compartments during monoseptic growth of microbial library clones, colony lysis, thermocycling and screening for sequence motifs via semi-quantitative fluorescence analyses. nl-Reactors were kept in suspension during all high-throughput steps which allowed performing the protocol in a highly space-effective fashion and at negligible expenses of consumables and reagents. As a first application, 11 high-quality microsatellites for polymorphism studies in cassava were isolated and sequenced out of a library of 20 000 clones in 2 days. The technology is widely scalable and we envision that throughputs for nl-reactor based screenings can be increased up to 100 000 and more samples per day thereby efficiently complementing protocols based on established deep-sequencing technologie

    Restriction landmark genomic scanning (RLGS) spot identification by second generation virtual RLGS in multiple genomes with multiple enzyme combinations.

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    BackgroundRestriction landmark genomic scanning (RLGS) is one of the most successfully applied methods for the identification of aberrant CpG island hypermethylation in cancer, as well as the identification of tissue specific methylation of CpG islands. However, a limitation to the utility of this method has been the ability to assign specific genomic sequences to RLGS spots, a process commonly referred to as "RLGS spot cloning."ResultsWe report the development of a virtual RLGS method (vRLGS) that allows for RLGS spot identification in any sequenced genome and with any enzyme combination. We report significant improvements in predicting DNA fragment migration patterns by incorporating sequence information into the migration models, and demonstrate a median Euclidian distance between actual and predicted spot migration of 0.18 centimeters for the most complex human RLGS pattern. We report the confirmed identification of 795 human and 530 mouse RLGS spots for the most commonly used enzyme combinations. We also developed a method to filter the virtual spots to reduce the number of extra spots seen on a virtual profile for both the mouse and human genomes. We demonstrate use of this filter to simplify spot cloning and to assist in the identification of spots exhibiting tissue-specific methylation.ConclusionThe new vRLGS system reported here is highly robust for the identification of novel RLGS spots. The migration models developed are not specific to the genome being studied or the enzyme combination being used, making this tool broadly applicable. The identification of hundreds of mouse and human RLGS spot loci confirms the strong bias of RLGS studies to focus on CpG islands and provides a valuable resource to rapidly study their methylation

    Computational Methods in Modeling Fusion Plasmas

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    Fusion provides an attractive potential alternative to using fossil fuels for energy. Fusion requires vastly less fuel resources than does current non-renewable energy processes (virtually a 100% reduction in the required mass of fuel needed). The fuel sources needed (mainly deuterium and lithium) are also highly abundant on the Earth and fusion generates minimal waste products. One of the biggest obstacles to practical fusion energy is how to contain the reactants long enough for energy output to significantly exceed energy input. The equations governing plasma dynamics and confinement are highly nonlinear and do not admit simple analytic solutions in realistic situations. To obtain predictions of various plasma confinement scenarios, it is often necessary to turn to other means, such as computational modeling, to simulate the relevant plasma dynamics. Evaluating the effectiveness and reliability of the computational methods used for simulation then becomes extremely important, especially when subsequently using your code to predict new physics to the scientific community. In this work, we present an effort to analyze the effectiveness of one of the computational techniques used in the NIMROD code, which code Eric Held (USU) and others in the scientific community have helped to develop. This method involves resolving something called the Grad-Shafranov equation, which governs the potential plasma equilibria that can exist in tokamak plasmas. Here we evaluate the effectiveness of the method and discuss the potential implications resulting from this analysis

    Closed-Shell Hartree-Fock: an Efficient Implementation Based on the Contraction of Integrals in the Primitive Basis

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    In this work a highly efficient, closed-shell restricted Hartree-Fock self-consistent-field (SCF) program has been developed. It has been written as a part of the ``Quantum Objects Library'' (QOL), which is developed at the Institute for Theoretical Chemistry at the University of Cologne. In the implementation presented here, the explicit transformation of the two-electron integrals from the primitive to the radial contracted, angularly transformed basis is avoided. The density matrix is obtained by diagonalizing the Fock matrix in the radial-angular-transformed basis. It is transformed to the primitive basis, and contracted with the integrals to give the Fock matrix, also in the primitive basis. To assure that solutions of the Fock equations are obtained in the transformed basis, the Fock matrix is transformed back to the radial contracted, angularly transformed basis after the density contraction step. Both one- and two-electron integrals are calculated using the ansatz of Obara-Saika (OS). For the evaluation of the two-electron integrals a code-generating ansatz is used. At compile time optimized code is generated, to be called at runtime. Numerical instabilities inherent in the Obara-Saika scheme were analyzed and eliminated. The code-generating ansatz was also used for the implementation of the density contraction. Contraction codes for both primitive and radial-angular-transformed bases were developed. Both two-electron integral evaluation and density contraction implementations have been optimized by explicit use of streaming single instruction multiple data (SIMD) extensions (SSE). Integral prescreening has been implemented on basis of the Schwarz inequality, and the differential density scheme is used. Convergence acceleration has been realized by implementing the direct inversion of the iterative subspace (DIIS) method. The developed SCF program has been parallelized using the open multi-processing (OMP) application programming interface (API). In final performance comparisons to commercially available programs competitive results were obtained

    Associations between tooth loss and prognostic biomarkers and the risk for cardiovascular events in patients with stable coronary heart disease

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    Background: Underlying mechanisms behind the hypothesized relationship between periodontal disease (PD) and coronary heart disease (CHD) have been insufficiently explored. We evaluated associations between self-reported tooth loss- a marker of PD- and prognostic biomarkers in 15,456 (97%) patients with stable CHD in the global STABILITY trial. Methods and results: Baseline blood samples were obtained and patients reported their number of teeth according to the following tooth loss levels: “26–32 (All)” [lowest level], “20–25”, “15–19”, “1–14”, and “No Teeth” [highest level]. Linear and Cox regression models assessed associations between tooth loss levels and biomarker levels, and the relationship between tooth loss levels and outcomes, respectively. After multivariable adjustment, the relative biomarker increase between the highest and the lowest tooth loss level was: high-sensitivity C-reactive protein 1.21 (95% confidence interval, 1.14–1.29), interleukin 6 1.14 (1.10–1.18), lipoprotein-associated phospholipase A2 activity 1.05 (1.03–1.06), growth differentiation factor 15 1.11 (1.08–1.14), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) 1.18 (1.11–1.25). No association was detected for high-sensitivity troponin T 1.02 (0.98–1.05). Some attenuation of the relationship between tooth loss and outcomes resulted from the addition of biomarkers to the multivariable analysis, of which NT-proBNP had the biggest impact. Conclusions: A graded and independent association between tooth loss and several prognostic biomarkers was observed, suggesting that tooth loss and its underlying mechanisms may be involved in multiple pathophysiological pathways also implicated in the development and prognosis of CHD. The association between tooth loss and cardiovascular death and stroke persisted despite comprehensive adjustment including prognostic biomarkers

    The Eastern Origins of the Rise of the West and the “Return” of Asia

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    With the current interest in China (and India) proliferating within the Western Academy, this article claims that what we are witnessing today is not the rise but the “return” of China (and India). Many academics assume that the West has been the dominant civilization in the world economy in the last 500 years and that the current “rise” of China threatens to knock the West off its perch. However, this article provides an alternative take to this cherished axiom of Eurocentric world history by inverting the standard belief that the West pioneered modernity and then expanded outwards to remake the world. Thus, I argue not only that globalization preceded the rise of the West but that it was Eastern-led on the one hand and that it enabled the Western breakthrough into modernity on the other. This, in turn, rests on my claim that Chinese development stems back not to 1978 but to 960 ce as the Sung Dynasty emerged and subsequently undertook a quasi-industrial miracle. Moreover, between 1450/1492 and ca. 1830 China lay at the centre of the nascent global economy, fanning the integration process alongside other key non-Western regions such as India and West Asia/North Africa. And, while the West was the dominant player after ca. 1830 down to the turn of the third millennium, nevertheless, what we witness today is the return of China to the centre of the global economy whence it came
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