12,085 research outputs found

    Innovative Hybridisation of Genetic Algorithms and Neural Networks in Detecting Marker Genes for Leukaemia Cancer

    Get PDF
    Methods for extracting marker genes that trigger the growth of cancerous cells from a high level of complexity microarrays are of much interest from the computing community. Through the identified genes, the pathology of cancerous cells can be revealed and early precaution can be taken to prevent further proliferation of cancerous cells. In this paper, we propose an innovative hybridised gene identification framework based on genetic algorithms and neural networks to identify marker genes for leukaemia disease. Our approach confirms that high classification accuracy does not ensure the optimal set of genes have been identified and our model delivers a more promising set of genes even with a lower classification accurac

    Anatomical Studies of Cca Penetration Associated With Conventional (Tooth) and With Micro (Needle) Incising

    Get PDF
    Individual tooth and needle incisions were made on radial and tangential surfaces of white spruce and jack pine heartwood test samples. The samples were pressure-treated with CCA preservative and then dissected in various planes to examine patterns of preservative penetration. Lateral movement of preservative from incisions was generally greater in the radial than in the tangential direction (average R/T ratio about 1.5). Longitudinal movement was in the range of 15 to 20 times that of lateral movement. Ray tissue facilitates movement in the radial plane, but difficulty is encountered in traversing latewood bands. An individual tooth incision resulted in a larger zone of treated wood but also in a greater amount of wood tissue damage than a needle incision. When compared as ratios of treated wood area to damaged wood area at a depth of 9 mm beneath the original treated surface, needle incisions were decidedly superior. For an equivalent degree of preservative treatment, conventional incising teeth damaged about ten times the amount of wood tissue as did incising needles

    Quantitative spectroscopy of extreme helium stars - Model atmospheres and a non-LTE abundance analysis of BD+10^\circ2179?

    Get PDF
    Extreme helium stars (EHe stars) are hydrogen-deficient supergiants of spectral type A and B. They are believed to result from mergers in double degenerate systems. In this paper we present a detailed quantitative non-LTE spectral analysis for BD+10^\circ2179, a prototype of this rare class of stars, using UVES and FEROS spectra covering the range from \sim3100 to 10 000 {\AA}. Atmosphere model computations were improved in two ways. First, since the UV metal line blanketing has a strong impact on the temperature-density stratification, we used the Atlas12 code. Additionally, We tested Atlas12 against the benchmark code Sterne3, and found only small differences in the temperature and density stratifications, and good agreement with the spectral energy distributions. Second, 12 chemical species were treated in non-LTE. Pronounced non-LTE effects occur in individual spectral lines but, for the majority, the effects are moderate to small. The spectroscopic parameters give TeffT_\mathrm{eff} = 17 300±\pm300 K and logg\log g = 2.80±\pm0.10, and an evolutionary mass of 0.55±\pm0.05 MM_\odot. The star is thus slightly hotter, more compact and less massive than found in previous studies. The kinematic properties imply a thick-disk membership, which is consistent with the metallicity [[Fe/H]1]\approx-1 and α\alpha-enhancement. The refined light-element abundances are consistent with the white dwarf merger scenario. We further discuss the observed helium spectrum in an appendix, detecting dipole-allowed transitions from about 150 multiplets plus the most comprehensive set of known/predicted isolated forbidden components to date. Moreover, a so far unreported series of pronounced forbidden He I components is detected in the optical-UV.Comment: Accepted for publication in MNRAS, 26 pages, 19 Figure

    Fixation of Juvenile Cambium from Two Coniferous Species for Ultrastructural Study

    Get PDF
    Samples of dormant and of actively growing cambial-zone tissue collected in June and March, respectively, from plantations of young white spruce (Picea glauca [Moench] Voss) and red pine (Pinus resinosa Ait.) near Ottawa, Canada, were fixed in five different solutions at three temperatures. Fixation quality was evaluated by electron microscopy.Not all cellular organelles were preserved equally well by the same fixative in the active and in the dormant conditions, or in both spruce and pine. In general, our best results were obtained with Karnovsky's fixative solution. Somewhat less satisfactory results were obtained with a glutaraldehyde-acrolein mixture followed by straight glutaraldehyde. Poorer results were obtained with a trialdehyde solution while a glutaraldehyde-osmium tetroxide cocktail undoubtedly provided the worst fixation.Different fixative temperatures had a marked effect on fixation quality only when phosphate buffer was used. There was little gained by prolonging the period of fixation beyond a few hours

    Time-domain Brillouin Scattering as a Local Temperature Probe in Liquids

    Full text link
    We present results of time-domain Brillouin scattering (TDBS) to determine the local temperature of liquids in contact to an optical transducer. TDBS is based on an ultrafast pump-probe technique to determine the light scattering frequency shift caused by the propagation of coherent acoustic waves in a sample. Since the temperature influences the Brillouin scattering frequency shift, the TDBS signal probes the local temperature of the liquid. Results for the extracted Brillouin scattering frequencies recorded at different liquid temperatures and at different laser powers - i.e. different steady state background temperatures- are shown to demonstrate the usefulness of TDBS as a temperature probe. This TDBS experimental scheme is a first step towards the investigation of ultrathin liquids measured by GHz ultrasonic probing.Comment: arXiv admin note: substantial text overlap with arXiv:1702.0107

    Response to comment on "solid recovered fuel: Materials flow analysis and fuel property development during the mechanical processing of biodried waste"

    Get PDF
    Laner and Cencic1 comment on Velis et al. (2013)2 clarifying certain points on the use of the material flow analysis (MFA) software STAN3. We welcome the correspondence and the opportunity this exchange provides to discuss optimal approaches to using STAN. In keeping with Velis et al.2 these physically impossible, and otherwise insignificant, negative flows have enabled improvements to STAN. Here, we elaborate on the practicalities of using STAN in our research and on the correctness and validation of our results, notwithstanding the inclusion of negative flows. We explain the contribution of our approach to solid waste management and resource recovery

    Quintessence Models and the Cosmological Evolution of alpha

    Full text link
    The cosmological evolution of a quintessence-like scalar field, phi, coupled to matter and gauge fields leads to effective modifications of the coupling constants and particle masses over time. We analyze a class of models where the scalar field potential V(phi) and the couplings to matter B(phi) admit common extremum in phi, as in the Damour-Polyakov ansatz. We find that even for the simplest choices of potentials and B(phi), the observational constraints on delta alpha/alpha coming from quasar absorption spectra, the Oklo phenomenon and Big Bang nucleosynthesis provide complementary constraints on the parameters of the model. We show the evolutionary history of these models in some detail and describe the effects of a varying mass for dark matter.Comment: 26 pages, 20 eps figure

    Strain and field modulation in bilayer graphene band structure

    Full text link
    Using an external electric field, one can modulate the bandgap of Bernal stacked bilayer graphene by breaking A-~B symmetry. We analyze strain effects on the bilayer graphene using the extended Huckel theory and find that reduced interlayer distance results in higher bandgap modulation, as expected. Furthermore, above about 2.5 angstrom interlayer distance, the bandgap is direct, follows a convex relation to electric field and saturates to a value determined by the interlayer distance. However, below about 2.5 angstrom, the bandgap is indirect, the trend becomes concave and a threshold electric field is observed, which also depends on the stacking distance.Comment: 3 pages, 5 figures - v1 and v2 are the same, uploaded twice - v3, some typos fixed and a reference adde
    corecore