1,014 research outputs found

    2D adaptive grid-based image analysis approach for biological networks

    Get PDF
    The accurate analysis of biological networks, enabled by the precise capture of their individual components, can reveal important underlying biological principles. Efficient image processing techniques are required to precisely identify and quantify the networks from complex images. In this paper, we present a novel approach for a weighted and undirected graph-based network reconstruction and quantification from 2D images using an adaptive rectangular mesh refinement approach. The proposed approach is able to efficiently identify the organizational principles of the network, capturing the underlying network structure, and computing relevant network topological properties. We validate the proposed approach by comparing it with the state-of-the-art method

    Arrival directions of large air showers, low-mu showers and old-age low-mu air showers observed at St. Chacaltaya

    Get PDF
    Arrival directions of air showers with primary energies in the range 10 to the 16.5 power eV to 10 to the 18th power eV show the first harmonic in right ascension (RA) with amplitude of 2.7 + or - 1.0% and phase of 13-16h. However, the second harmonic in RA slightly seen for showers in the range 10 to the 18th power eV to 10 to the 19th power eV disappeared by accumulation of observed showers. The distribution of arrival directions of low-mu air showers with primary energies around 10 to the 15th power eV observed at Chacaltaya from 1962 to 1967 is referred to, relating to the above-mentioned first harmonic. Also presented in this paper are arrival directions of old-age low-mu air showers observed at Chacaltaya from 1962 to 1967, for recent interest in gamma-ray air showers

    Digestão de tecido vegetal em forno de micro-ondas via sistema aberto.

    Get PDF
    bitstream/item/72356/1/ID-29940.pd

    Thermoelectric properties of the layered Pd oxide R_2PdO_4 (R = La, Nd, Sm and Gd)

    Full text link
    We prepared polycrystalline samples of R2_2PdO4_4 (R = La, Nd, Sm and Gd) using a NaCl-flux technique. The measured resistivity is of the order of 103104^3-10^4 Ω\Omegacm at room temperature, which is two orders of magnitude smaller than the values reported so far. We further studied the substitution effects of Ce for Nd in Nd1.9_{1.9}Ce0.1_{0.1}PdO4_4, where the substituted Ce decreases the resistivity and the magnitude of the thermopower. The activation energy gap of 70-80 meV and the effective mass of 15 evaluated from the measured data are suitable for thermoelectric materials, but the mobility of 106^{-6} cm2^2/Vs is much lower than a typical value of 1-10 cm2^2/Vs for other thermoelectric oxides.Comment: 5 pages, 5 figures, to appear in J. Phys. Soc. Jp

    Femtosecond X-ray emission study of the spin cross-over dynamics in haem proteins

    Full text link
    In haemoglobin (consisting of four globular myoglobin-like subunits), the change from the low-spin (LS) hexacoordinated haem to the high spin (HS) pentacoordinated domed form upon ligand detachment and the reverse process upon ligand binding, represent the transition states that ultimately drive the respiratory function. Visible-ultraviolet light has long been used to mimic the ligand release from the haem by photodissociation, while its recombination was monitored using time-resolved infrared to ultraviolet spectroscopic tools. However, these are neither element- nor spin-sensitive. Here we investigate the transition state in the case of Myoglobin-NO (MbNO) using femtosecond Fe Kalpha and Kbeta non-resonant X-ray emission spectroscopy (XES) at an X-ray free-electron laser upon photolysis of the Fe-NO bond. We find that the photoinduced change from the LS (S = 1/2) MbNO to the HS (S = 2) deoxy-myoglobin (deoxyMb) haem occurs in ca. 800 fs, and that it proceeds via an intermediate (S = 1) spin state. The XES observables also show that upon NO recombination to deoxyMb, the return to the planar MbNO ground state is an electronic relaxation from HS to LS taking place in ca. 30 ps. Thus, the entire ligand dissociation-recombination cycle in MbNO is a spin cross-over followed by a reverse spin cross-over process

    ISRM-Suggested Method for Determining the Mode I Static Fracture Toughness Using Semi-Circular Bend Specimen

    Get PDF
    The International Society for Rock Mechanics has so far developed two standard methods for the determination of static fracture toughness of rock. They used three different core based specimens and tests were to be performed on a typical laboratory compression or tension load frame. Another method to determine the mode I fracture toughness of rock using semicircular bend specimen is herein presented. The specimen is semicircular in shape and made from typical cores taken from the rock with any relative material directions noted. The specimens are tested in three-point bending using a laboratory compression test instrument. The failure load along with its dimensions is used to determine the fracture toughness. Most sedimentary rocks which are layered in structure may exhibit fracture properties that depend on the orientation and therefore measurements in more than one material direction may be necessary. The fracture toughness measurements are expected to yield a size-independent material property if certain minimum specimen size requirements are satisfied

    Flow diagnostics and visualization in wind tunnels and flight

    Get PDF
    The Langley Research Center has a concentrated and directed effort under way to develop both conventional and non-intrusive diagnostic instrumentation. These instruments are being developed to operate over large Mach number, total temperature, and total pressure ranges. Efforts are being made to evaluate the measurements made by the various instruments to determine the most accurate and reliable instrument to be used under a given flow environment. Although only one flow visualization technique was described, there are many different types presently being used at Langley Research Center
    corecore