2,927 research outputs found

    Cosmological Simulation for Fuzzy Dark Matter Model

    Full text link
    Fuzzy Dark Matter (FDM), motivated by string theory, has recently become a hot candidate for dark matter. The rest mass of FDM is believed to be ∼10−22\sim 10^{-22}eV and the corresponding de-Broglie wave length is ∼1\sim 1kpc. Therefore, the quantum effect of FDM plays an important role in structure formation. In order to study the cosmological structure formation in FDM model, several simulation techniques have been introduced. We review the current status and challenges in the cosmological simulation for the FDM model in this paper.Comment: 10 pages, 2 tables, published on Front. Astron. Space Sci. under the topic: Dark Matter - Where is it? What is it

    Topological and organizational properties of the products of house-keeping and tissue-specific genes in protein-protein interaction networks

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Human cells of various tissue types differ greatly in morphology despite having the same set of genetic information. Some genes are expressed in all cell types to perform house-keeping functions, while some are selectively expressed to perform tissue-specific functions. In this study, we wished to elucidate how proteins encoded by human house-keeping genes and tissue-specific genes are organized in human protein-protein interaction networks. We constructed protein-protein interaction networks for different tissue types using two gene expression datasets and one protein-protein interaction database. We then calculated three network indices of topological importance, the degree, closeness, and betweenness centralities, to measure the network position of proteins encoded by house-keeping and tissue-specific genes, and quantified their local connectivity structure.</p> <p>Results</p> <p>Compared to a random selection of proteins, house-keeping gene-encoded proteins tended to have a greater number of directly interacting neighbors and occupy network positions in several shortest paths of interaction between protein pairs, whereas tissue-specific gene-encoded proteins did not. In addition, house-keeping gene-encoded proteins tended to connect with other house-keeping gene-encoded proteins in all tissue types, whereas tissue-specific gene-encoded proteins also tended to connect with other tissue-specific gene-encoded proteins, but only in approximately half of the tissue types examined.</p> <p>Conclusion</p> <p>Our analysis showed that house-keeping gene-encoded proteins tend to occupy important network positions, while those encoded by tissue-specific genes do not. The biological implications of our findings were discussed and we proposed a hypothesis regarding how cells organize their protein tools in protein-protein interaction networks. Our results led us to speculate that house-keeping gene-encoded proteins might form a core in human protein-protein interaction networks, while clusters of tissue-specific gene-encoded proteins are attached to the core at more peripheral positions of the networks.</p

    Numerical Analysis on Color Preference and Visual Comfort from Eye Tracking Technique

    Get PDF
    Color preferences in engineering are very important, and there exists relationship between color preference and visual comfort. In this study, there are thirty university students who participated in the experiment, supplemented by pre- and posttest questionnaires, which lasted about an hour. The main purpose of this study is to explore the visual effects of different color assignment with subjective color preferences via eye tracking technology. Eye-movement data through a nonlinear analysis detect slight differences in color preferences and visual comfort, suggesting effective physiological indicators as extensive future research discussed. Results found that the average pupil size of eye-movement indicators can effectively reflect the differences of color preferences and visual comfort. This study more confirmed that the subjective feeling will make people have misjudgment

    Network partitioning into tree hierarchies

    Full text link
    This paper addresses the problem of partitioning a circuit into a tree hierarchy with an objective of minimizing a glo-bal interconnection cost. An efficient and effective algo-rithm is necessary when the circuit is huge and the tree has many levels of hierarchy. We propose a heuristic algorithm for improving a partition with respect to a given tree struc-ture. The algorithm utilizes the tree hierarchy as an efficient mechanism for iterative improvement. We also extend the tree hierarchy to apply a multi-phase partitioning approach. Experimental results show that the algorithm significantly improves the initial partitions produced by multiway parti-tioning and by recursive partitioning. 1

    A Monte Carlo Study of Erraticity Behavior in Nucleus-Nucleus Collisions at High Energies

    Get PDF
    It is demonstrated using Monte Carlo simulation that in different nucleus−-nucleus collision samples, the increase of the fluctuation of event factorial moments with decreasing phase space scale, called erraticity, is still dominated by the statistical fluctuations. This result does not depend on the Monte Carlo models. Nor does it depend on the concrete conditions, e.g. the collision energy, the mass of colliding nuclei, the cut of phase space, etc.. This means that the erraticity method is sensitive to the appearance of novel physics in the central collisions of heavy nuclei.Comment: 9 pages, 4 figures (in eps form

    Effect of diabetes on mortality and length of hospital stay in patients with renal or perinephric abscess

    Get PDF
    OBJECTIVES: We compared the risk of in-hospital mortality and the length of hospital stay between diabetic and non-diabetic patients hospitalized for renal or perinephric abscess. METHOD: The data analyzed in this study were retrieved from Taiwan's National Health Insurance claims. The risk of in-hospital mortality and the length of hospital stay were compared between 1,715 diabetic patients, hospitalized because of renal or perinephric abscess in Taiwan between 1997 and 2007, and a random sample of 477 non-diabetes patients with renal or perinephric abscess. RESULTS: The in-hospital mortality rates from renal or perinephric abscess for the diabetic patients and the non-diabetic patients were not different, at 2.3% and 3.4%, respectively. However, diabetes was significantly associated with a longer length of hospital stay among patients with renal abscess, by 3.38 days (95% confidence interval [CI]: 1.59-5.17). CONCLUSIONS: Diabetes does not increase the risk of in-hospital mortality from renal or perinephric abscess. Nevertheless, appropriate management of patients with diabetes and concurrent renal or perinephric abscess is essential to reduce the length of hospital stay

    Dipole field driven morphology evolution in biomimetic vaterite

    Get PDF
    Morphology evolution is an important process in naturally occurring biominerals. To investigate the interaction between biomolecules and inorganic components in the construction of biominerals, biomimetic hexagonal prism vaterite crystals were hydrothermally prepared through a reaction of urea with calcium nitrate tetrahydrate, whilst gelatin was added as a structure directing agent. An extraordinary morphology evolution was observed. The time dependent growth was investigated by using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and thermogravimetric analysis. In the early stages, vaterite nanocrystallites, ~5 nm in diameter, underwent aggregation with gelatin molecules and precursor molecules into 50 nm sized clusters. Some nanoneedles, consisting of self-orientated nanocrystallites embedded within a soft gelatin matrix, were developed on the surface of disordered cores to form spherulite particles, with a similar morphology to natural spherulite biominerals. Further growth was affected by the high viscosity of gelatin, resulting in ellipsoid particles composed of spherulitically ordered needles. It is proposed that surface adsorbed gelatin induces the formation of dipoles in the nanocrystallites and interaction between the dipoles is the driving force of the alignment of the nanocrystallites. Further growth might create a relatively strong and mirror-symmetric dipolar field, followed by a morphology change from ellipsoidal with a cell-division like splitting, to twin-cauliflower, dumbbell, cylindrical and finally to hexagonal prism particles. In this morphology evolution, the alignment of the crystallites changes from 1D linear manner (single crystal like) to 3D radial pattern, and finally to mirror symmetric 1D linear manner. This newly proposed mechanism sheds light on the microstructural evolution in many biomimetic materials and biominerals.PostprintPeer reviewe

    Improving Performance of CIGS Solar Cells by Annealing ITO Thin Films Electrodes

    Get PDF
    Indium tin oxide (ITO) thin films were grown on glass substrates by direct current (DC) reactive magnetron sputtering at room temperature. Annealing at the optimal temperature can considerably improve the composition, structure, optical properties, and electrical properties of the ITO film. An ITO sample with a favorable crystalline structure was obtained by annealing in fixed oxygen/argon ratio of 0.03 at 400°C for 30 min. The carrier concentration, mobility, resistivity, band gap, transmission in the visible-light region, and transmission in the near-IR regions of the ITO sample were -1.6E+20 cm−3, 2.7E+01 cm2/Vs, 1.4E-03 Ohm-cm, 3.2 eV, 89.1%, and 94.7%, respectively. Thus, annealing improved the average transmissions (400–1200 nm) of the ITO film by 16.36%. Moreover, annealing a copper-indium-gallium-diselenide (CIGS) solar cell at 400°C for 30 min in air improved its efficiency by 18.75%. The characteristics of annealing ITO films importantly affect the structural, morphological, electrical, and optical properties of ITO films that are used in solar cells
    • …
    corecore