1,456 research outputs found

    Neumann-Hoffman Code Evasion and Stripping Method for BeiDou Software-defined Receiver

    Get PDF
    © 2016 The Royal Institute of Navigation. The acquisition and tracking strategies of the BeiDou navigation satellite signals are affected by the modulation of Neumann-Hoffman code (NH code), which increases the complexity of receiver baseband signal processing. Based on the analysis of probability statistics of the NH code, a special sequence of incoming signals is proposed to evade the bit transitions caused by the NH code, and an NH Code Evasion and Stripping method (NCES) based on the NH-pre-modulated code is proposed. The NCES can be applied in both 20-bit NH code and 10-bit NH code. The fine acquisition eliminates the impact of NH code on the traditional tracking loop. These methods were verified with a BeiDou PC-based software-defined receiver using the actual sampled signals. Compared with other acquisition schemes which try to determine or ignore the NH code phase, the NCES needs fewer incoming signals and the actual runtime is greatly reduced without sacrificing much time to search in the secondary code dimension, and the success rate of acquisition is effectively improved. An extension of Fast Fourier Transform (FFT)-based parallel code-phase search acquisition gives the NCES an advantage in engineering applications

    FABP7 (fatty acid binding protein 7, brain)

    Get PDF
    Review on FABP7, with data on DNA/RNA, on the protein encoded and where the gene is implicated

    Kinematic modelling of a 3-axis NC machine tool in linear and circular interpolation

    Full text link
    Machining time is a major performance criterion when it comes to high-speed machining. CAM software can help in estimating that time for a given strategy. But in practice, CAM-programmed feed rates are rarely achieved, especially where complex surface finishing is concerned. This means that machining time forecasts are often more than one step removed from reality. The reason behind this is that CAM routines do not take either the dynamic performances of the machines or their specific machining tolerances into account. The present article seeks to improve simulation of high-speed NC machine dynamic behaviour and machining time prediction, offering two models. The first contributes through enhanced simulation of three-axis paths in linear and circular interpolation, taking high-speed machine accelerations and jerks into account. The second model allows transition passages between blocks to be integrated in the simulation by adding in a polynomial transition path that caters for the true machining environment tolerances. Models are based on respect for path monitoring. Experimental validation shows the contribution of polynomial modelling of the transition passage due to the absence of a leap in acceleration. Simulation error on the machining time prediction remains below 1%

    Role of CD56-expressing immature biliary epithelial cells in biliary atresia

    Get PDF
    published_or_final_versio

    Analysis of Kif5b Expression during Mouse Kidney Development

    Get PDF
    published_or_final_versio

    Determination of trace amounts of gold(III) by cathodic stripping voltammetry using a bacteria-modified carbon paste electrode

    Get PDF
    A bacteria-modified carbon paste electrode has been prepared and used for the very sensitive and selective determination of trace amounts of gold(III). The modified electrode was able to detect a solution of 1.0 ppb Au(III) by applying cathodic stripping voltammetry. Advantages of the bacteria-modified electrode include high sensitivity, good stability, low cost and simple preparation. It could be a new class of modified electrode with practical value

    Metamorphism and geochronology of the spinel−cordierite granulite in the Mirror Peninsula, East Antarctica

    Get PDF
    Objective  The Prydz Bay belt in East Antarctica recorded two significant tectono-thermal events, the Grenvillian event and the Pan-African event, which are considered to be closely related to the evolution of the Rodinia and Gondwana supercontinents. However, the geological history and the tectonic nature of the two events remain controversial.   Methods  Mineralogical and petrological analyses, phase equilibria modelling and zircon geochronology are combined to investigate the spinel−cordierite granulite from the Mirror Peninsula in order to better understand the tectono-thermal history of the Prydz Bay belt.   Results  The spinel−cordierite granulite contains different stages of mineral assemblages. The major stage of mineral assemblage involves cordierite, spinel, biotite, sillimanite, K-feldspar and minor garnet and ilmenite. The later stage of mineral assemblage is indicated by the emergence of magnetite as the increasing volumes of biotite and cordierite. Minor garnet and corundum are locally preserved, implying the mineral reaction ‘g+cor→sp+sill’ and more garnet and corundum in the peak stage. The garnet grains consist of 70%−72% almandine, 20%−22% pyrope, ~4% grossularite and ~4% spessartine. The XFe (Fe2+/(Fe2++Mg2+)) of representative garnet grains ranges from 0.77 to 0.80. The spinel exhibits an XFe range from 0.80 to 0.86. Different cordierite grains have similar compositions with Al of 3.89−3.93 a.p.f.u (atoms per formula unit) and XFe of 0.32−0.36. Biotite has high TiO2 (4.13%−5.23%) and Ti (0.23−0.30 a.p.f.u). K-feldspar grains consist of 78%−85% orthoclase, 15%−23% albite and ~1% anorthite. Based on the mineral compositions and phase equilibrium modelling, the pressure−temperature (P−T) conditions of the major stage of mineral assemblage are constrained to 870−910 °C and 0.64−0.69 GPa, followed by later retrogression to 810−820°C and 0.49−0.53 GPa. A peak stage with higher P−T conditions (T>910 ℃, P>0.69 GPa) can be inferred based on the relict peak minerals and characteristic mineral compositions (e.g. Ti in biotite). Zircon grains commonly show core-mantle-rim structures in cathodoluminescence (CL) images. The LA−ICP−MS zircon U−Pb dating analyses reveal a wide age range from 613±7 Ma to 877±9 Ma (except a maximum of 916±11 Ma) for the cores. The zircon bright rims yield a weighted mean age of 526±8 Ma with a wide range of Th/U (0.06−1.23), mostly higher than 0.1.   Conclusion  Based on the results, a few conclusions can be drawn: (1) The spinel−cordierite granulite recorded medium−low pressure/high-ultrahigh temperature metamorphism with a clockwise P−T evolution path and high dT/dP. (2) The results of zircon geochronological analysis show that zircon cores mainly record U−Pb ages in the range of 800~600 Ma, younger than typical ages of Grenvillian events, which may reflect younger inherited zircon cores or significant isotopic resetting. (3) The age of ~530 Ma of zircon rims is interpreted to represent the post-peak cooling stage of the Pan-African tectono-thermal event. [Significance] This study examined the P−T conditions and the zircon ages of the spinel−cordierite granulite in the Mirror Peninsula. In combination with previous results, the P−T−t path constructed for the spinel−cordierite granulite provides new constraints on the evolution of the Prydz Bay belt during the Pan-African period

    Oxygen-glucose deprivation induces ATP release via maxi-anion channels in astrocytes

    Get PDF
    ATP represents a major gliotransmitter that serves as a signaling molecule for the cross talk between glial and neuronal cells. ATP has been shown to be released by astrocytes in response to a number of stimuli under nonischemic conditions. In this study, using a luciferin-luciferase assay, we found that mouse astrocytes in primary culture also exhibit massive release of ATP in response to ischemic stress mimicked by oxygen-glucose deprivation (OGD). Using a biosensor technique, the local ATP concentration at the surface of single astrocytes was found to increase to around 4 ΌM. The OGD-induced ATP release was inhibited by Gd3+ and arachidonic acid but not by blockers of volume-sensitive outwardly rectifying Cl− channels, cystic fibrosis transmembrane conductance regulator (CFTR), multidrug resistance-related protein (MRP), connexin or pannexin hemichannels, P2X7 receptors, and exocytotic vesicular transport. In cell-attached patches on single astrocytes, OGD caused activation of maxi-anion channels that were sensitive to Gd3+ and arachidonic acid. The channel was found to be permeable to ATP4− with a permeability ratio of PATP/PCl = 0.11. Thus, it is concluded that ischemic stress induces ATP release from astrocytes and that the maxi-anion channel may serve as a major ATP-releasing pathway under ischemic conditions
    • 

    corecore