2,519 research outputs found

    Physically Feasible Decomposition of Engino®^{\circledR} Toy Models: A Graph Theoretic Approach

    Full text link
    During the 125th European Study Group with Industry held in Limassol, Cyprus, 5-9 December 2016, one of the participating companies, Engino.net Ltd, posed a very interesting challenge to the members of the study group. Engino.net Ltd is a Cypriot company, founded in 2004, that produces a series of toy sets -- the Engino®^{\circledR} toy sets -- consisting of a number of building blocks which can be assembled by pupils to compose toy models. Depending on the contents of a particular toy set, the company has developed a number of models that can be built utilizing the blocks present in the set, however the production of a step-by-step assembly manual for each model could only be done manually. The goal of the challenge posed by the company was to implement a procedure to automatically generate the assembly instructions for a given toy. In the present paper we propose a graph-theoretic approach to model the problem and provide a series of results to solve it by employing modified versions of well established algorithms in graph theory. An algorithmic procedure to obtain a hierarchical, physically feasible decomposition of a given toy model, from which the assembly instructions can be recovered, is proposed.Comment: Final version, accepted for publication in the European Journal of Applied Mathematic

    The Complexity of Hex and the Jordan Curve Theorem

    Get PDF

    Correlations and Pair Formation in a Repulsively Interacting Fermi Gas

    Full text link
    A degenerate Fermi gas is rapidly quenched into the regime of strong effective repulsion near a Feshbach resonance. The spin fluctuations are monitored using speckle imaging and, contrary to several theoretical predictions, the samples remain in the paramagnetic phase for arbitrarily large scattering length. Over a wide range of interaction strengths a rapid decay into bound pairs is observed over times on the order of 10\hbar/E_F, preventing the study of equilibrium phases of strongly repulsive fermions. Our work suggests that a Fermi gas with strong short-range repulsive interactions does not undergo a ferromagnetic phase transition

    Analisis Faktor-faktor yang Mempengaruhi Kreativitas Akuntan

    Full text link
    This study aims to examine the influence of internal factors for the creativity accountans. Accounting is considered as the science is far from creativity. This causes an accountant is prevented from being creative possibilities. Accountants will be closed opportunities and the chance to be creative. This study examined the influence of ethics to the creativity accountant by Bryant, et al (2011) and Nurcahyo (2012). Ethics is measured using the dimensions of idealism and relativism. In addition, this study also examines the effect of job tenure, gender and intellectual of the creativity accountant.The population of this study is the auditor who works in the firm in the city of Semarang. The sample was an auditor who works in the firm in the city of Semarang with sampling techniques through sampling covinience. Data were collected through questionnaires and analyzed using multiple regressions.The results showed that the job tenure and gender had no effect on creativity accountant. In addition, intellectual and relativism significantly positive effect on creativity accountant. Idealism significantly negative effect on creativity accountant

    Suppression of Density Fluctuations in a Quantum Degenerate Fermi Gas

    Full text link
    We study density profiles of an ideal Fermi gas and observe Pauli suppression of density fluctuations (atom shot noise) for cold clouds deep in the quantum degenerate regime. Strong suppression is observed for probe volumes containing more than 10,000 atoms. Measuring the level of suppression provides sensitive thermometry at low temperatures. After this method of sensitive noise measurements has been validated with an ideal Fermi gas, it can now be applied to characterize phase transitions in strongly correlated many-body systems.Comment: minor edit: fixed technical problem with arxiv's processing of .eps figur

    Evaluating the accuracy of diffusion MRI models in white matter

    Full text link
    Models of diffusion MRI within a voxel are useful for making inferences about the properties of the tissue and inferring fiber orientation distribution used by tractography algorithms. A useful model must fit the data accurately. However, evaluations of model-accuracy of some of the models that are commonly used in analyzing human white matter have not been published before. Here, we evaluate model-accuracy of the two main classes of diffusion MRI models. The diffusion tensor model (DTM) summarizes diffusion as a 3-dimensional Gaussian distribution. Sparse fascicle models (SFM) summarize the signal as a linear sum of signals originating from a collection of fascicles oriented in different directions. We use cross-validation to assess model-accuracy at different gradient amplitudes (b-values) throughout the white matter. Specifically, we fit each model to all the white matter voxels in one data set and then use the model to predict a second, independent data set. This is the first evaluation of model-accuracy of these models. In most of the white matter the DTM predicts the data more accurately than test-retest reliability; SFM model-accuracy is higher than test-retest reliability and also higher than the DTM, particularly for measurements with (a) a b-value above 1000 in locations containing fiber crossings, and (b) in the regions of the brain surrounding the optic radiations. The SFM also has better parameter-validity: it more accurately estimates the fiber orientation distribution function (fODF) in each voxel, which is useful for fiber tracking

    Mouse ooplasm confers context-specific reprogramming capacity

    Get PDF
    Enucleated oocytes have the distinctive ability to reprogram somatic nuclei back to totipotency. Here, we investigate genome-scale DNA methylation patterns after nuclear transfer and compare them to the dynamics at fertilization. We identify specific targets for DNA demethylation after nuclear transfer, such as germline-associated promoters, as well as unique limitations that include certain repetitive element classes.National Institutes of Health (U.S.) (Grant 5DP1OD003958

    Tensor interaction constraints from beta decay recoil spin asymmetry of trapped atoms

    Get PDF
    We have measured the angular distribution of recoiling daughter nuclei emitted from the Gamow-Teller β\beta decay of spin-polarized 80^{80}Rb. The asymmetry of this distribution vanishes to lowest order in the Standard Model (SM) in pure Gamow-Teller decays, producing an observable very sensitive to new interactions. We measure the non-SM contribution to the asymmetry to be ATA_{T}= 0.015 ±\pm 0.029 (stat) ±\pm 0.019 (syst), consistent with the SM prediction. We constrain higher-order SM corrections using the measured momentum dependence of the asymmetry, and their remaining uncertainty dominates the systematic error. Future progress in determining the weak magnetism term theoretically or experimentally would reduce the final errors. We describe the resulting constraints on fundamental 4-Fermi tensor interactions.Comment: 11 pages, 13 figures; v2 published in Phys. Rev. C, with referee clarifications and figures improved for black-and-whit
    corecore