2,090 research outputs found

    Pareto Principle in Datamining: an Above-Average Fencing Algorithm

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    This paper formulates a new datamining problem: which subset of input space has the relatively highest output where the minimal size of this subset is given. This can be useful where usual datamining methods fail because of error distribution asymmetry. The paper provides a novel algorithm for this datamining problem, and compares it with clustering of above-average individuals

    Integration of CFD Methods into Concurrent Design of Internal Combustion Engine

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    This paper describes patterns of algorithms for different innovative levels of design at parametric, configuration and conceptual levels. They can be applied to Computer-aided Engine Design (CED). Data structures, process simulation hierarchy, engine simulation modules and the requirements for further development are described. An example of advanced thermodynamics modeling of combustion engines is included

    Testing for Markovian Character and Modeling of Intermittency in Solar Wind Turbulence

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    We present results of statistical analysis of solar wind turbulence using an approach based on the theory of Markov processes. It is shown that the Chapman-Kolmogorov equation is approximately satisfied for the turbulent cascade. We evaluate the first two Kramers-Moyal coefficients from experimental data and show that the solution of the resulting Fokker-Planck equation agrees well with experimental probability distributions. Our results suggest the presence of a local transfer mechanism for magnetic field fluctuations in solar wind turbulence

    Proteome-wide measurement of non-canonical bacterial mistranslation by quantitative mass spectrometry of protein modifications.

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    The genetic code is virtually universal in biology and was likely established before the advent of cellular life. The extent to which mistranslation occurs is poorly understood and presents a fundamental question in basic research and production of recombinant proteins. Here we used shotgun proteomics combined with unbiased protein modification analysis to quantitatively analyze in vivo mistranslation in an E. coli strain with a defect in the editing mechanism of leucyl-tRNA synthetase. We detected the misincorporation of a non-proteinogenic amino acid norvaline on 10% of all measured leucine residues under microaerobic conditions and revealed preferential deployment of a tRNA(Leu)(CAG) isoacceptor during norvaline misincorporation. The strain with the norvalylated proteome demonstrated a substantial reduction in cell fitness under both prolonged aerobic and microaerobic cultivation. Unlike norvaline, isoleucine did not substitute for leucine even under harsh error-prone conditions. Our study introduces shotgun proteomics as a powerful tool in quantitative analysis of mistranslation

    Threshold Laws for the Break-up of Atomic Particles into Several Charged Fragments

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    The processes with three or more charged particles in the final state exhibit particular threshold behavior, as inferred by the famous Wannier law for (2e + ion) system. We formulate a general solution which determines the threshold behavior of the cross section for multiple fragmentation. Applications to several systems of particular importance with three, four and five leptons (electrons and positrons) in the field of charged core; and two pairs of identical particles with opposite charges are presented. New threshold exponents for these systems are predicted, while some previously suggested threshold laws are revised.Comment: 40 pages, Revtex, scheduled for the July issue of Phys.Rev.A (1998

    The neuropeptide complement of the marine annelid Platynereis dumerilii.

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    This is the final version of the article. Available from BioMed Central via the DOI in this record.BACKGROUND: The marine annelid Platynereis dumerilii is emerging as a powerful lophotrochozoan experimental model for evolutionary developmental biology (evo-devo) and neurobiology. Recent studies revealed the presence of conserved neuropeptidergic signaling in Platynereis, including vasotocin/neurophysin, myoinhibitory peptide and opioid peptidergic systems. Despite these advances, comprehensive peptidome resources have yet to be reported. RESULTS: The present work describes the neuropeptidome of Platynereis. We established a large transcriptome resource, consisting of stage-specific next-generation sequencing datasets and 77,419 expressed sequence tags. Using this information and a combination of bioinformatic searches and mass spectrometry analyses, we increased the known proneuropeptide (pNP) complement of Platynereis to 98. Based on sequence homology to metazoan pNPs, Platynereis pNPs were grouped into ancient eumetazoan, bilaterian, protostome, lophotrochozoan, and annelid families, and pNPs only found in Platynereis. Compared to the planarian Schmidtea mediterranea, the only other lophotrochozoan with a large-scale pNP resource, Platynereis has a remarkably full complement of conserved pNPs, with 53 pNPs belonging to ancient eumetazoan or bilaterian families. Our comprehensive search strategy, combined with analyses of sequence conservation, also allowed us to define several novel lophotrochozoan and annelid pNP families. The stage-specific transcriptome datasets also allowed us to map changes in pNP expression throughout the Platynereis life cycle. CONCLUSION: The large repertoire of conserved pNPs in Platynereis highlights the usefulness of annelids in comparative neuroendocrinology. This work establishes a reference dataset for comparative peptidomics in lophotrochozoans and provides the basis for future studies of Platynereis peptidergic signaling.This work was supported by Max Planck Society Sequencing Grant M.IF.A.ENTW8050 to GJ. The research leading to these results was supported by the European Research Council under European Union Seventh Framework Program FP7/2007–2013 and European Research Council Grant Agreement 260821

    An Integrated Approach to Real-Time Mobile Robot Control in Partially Known Indoor Environments

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    In this paper we present a navigation method for mobile robots in partially known indoor environments based on integration of graph based search algorithms and dynamic window local obstacle avoidance method. With the attention on a dynamic environment three different graph based search algorithms for global geometrical path planning are considered and compared: A*, D* and focussed D* algorithm. The admissible robot trajectories are generated in the dynamic window local obstacle avoider module that ensures safe robot operation. A simple and efficient procedure to the selection of appropriate motion commands based upon alignment of acquired trajectories and global geometric path is proposed. The initial a priori knowledge is used about environment in the form of the occupancy grid map that is incrementally updated in runtime. The algorithms were verified both in simulation and experimentally on a Pioneer 2DX mobile robot using laser range sensor where a good correlation was proven

    Differential Impacts of Willow and Mineral Fertilizer on Bacterial Communities and Biodegradation in Diesel Fuel Oil-Contaminated Soil.

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    Despite decades of research there is limited understanding of how vegetation impacts the ability of microbial communities to process organic contaminants in soil. Using a combination of traditional and molecular assays, we examined how phytoremediation with willow and/or fertilization affected the microbial community present and active in the transformation of diesel contaminants. In a pot study, willow had a significant role in structuring the total bacterial community and resulted in significant decreases in diesel range organics (DRO). However, stable isotope probing (SIP) indicated that fertilizer drove the differences seen in community structure and function. Finally, analysis of the total variance in both pot and SIP experiments indicated an interactive effect between willow and fertilizer on the bacterial communities. This study clearly demonstrates that a willow native to Alaska accelerates DRO degradation, and together with fertilizer, increases aromatic degradation by shifting microbial community structure and the identity of active naphthalene degraders

    Universal description of the rotational-vibrational spectrum of three particles with zero-range interactions

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    A comprehensive universal description of the rotational-vibrational spectrum for two identical particles of mass mm and the third particle of the mass m1m_1 in the zero-range limit of the interaction between different particles is given for arbitrary values of the mass ratio m/m1m/m_1 and the total angular momentum LL. If the two-body scattering length is positive, a number of vibrational states is finite for Lc(m/m1)LLb(m/m1)L_c(m/m_1) \le L \le L_b(m/m_1), zero for L>Lb(m/m1)L>L_b(m/m_1), and infinite for L<Lc(m/m1)L<L_c(m/m_1). If the two-body scattering length is negative, a number of states is either zero for LLc(m/m1)L \ge L_c(m/m_1) or infinite for L<Lc(m/m1)L<L_c(m/m_1). For a finite number of vibrational states, all the binding energies are described by the universal function ϵLN(m/m1)=E(ξ,η)\epsilon_{LN}(m/m_1) = {\cal E}(\xi, \eta), where ξ=N1/2L(L+1)\xi=\displaystyle\frac{N-1/2}{\sqrt{L(L + 1)}}, η=mm1L(L+1)\eta=\displaystyle\sqrt{\frac{m}{m_1 L (L + 1)}},and NN is the vibrational quantum number. This scaling dependence is in agreement with the numerical calculations for L>2L > 2 and only slightly deviates from those for L=1,2L = 1, 2. The universal description implies that the critical values Lc(m/m1)L_c(m/m_1) and Lb(m/m1)L_b(m/m_1) increase as 0.401m/m10.401 \sqrt{m/m_1} and 0.563m/m10.563 \sqrt{m/m_1}, respectively, while a number of vibrational states for LLc(m/m1)L \ge L_c(m/m_1) is within the range NNmax1.1L(L+1)+1/2N \le N_{max} \approx 1.1 \sqrt{L(L+1)}+1/2
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