The beam impedance of monopole modes in a pipe with periodic, smooth and shallow corrugation has been calculated. The approach uses an orthogonal TM field expansion with Bessel functions and an impedance boundary condition, which takes into account resistive wall effects. The approach is valid for corrugations with period lengths larger, smaller and of the same order as the free space wavelengt...

LNA with Current Reuse and Zero-Pole Cancellation Chunbao Ding, Wanrong Zhang, Dongyue Jin, Hongyun Xie, Pei Shen, Liang Chen, School of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124, China Abstract—A low power cascode SiGe BiCMOS low noise amplifier (LNA) with current reuse and zero-pole cancellation is presented for ultra-wideband (UWB) appli...

in this research، job opportunities have been examined among 26 productive sectors of iran's economy by using input-output table in 2001.from viewpoint of employment ،production and value added، the key sectors has been diagnosed by using mri ، elasticity of input-output table، backward and forward linkages and june's corrective methods. then، job opportunities has been analyzed among...

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The role of potassium conductances in determining input resistance was studied in 166 genioglossal (GG) motoneurons using sharp electrode recording in brain stem slices of the rats aged 5-7 days, 13-15 days, and 19-24 days postnatal (P). A high magnesium (Mg(2+); 6 mM) perfusate was used to block calcium-mediated synaptic release while intracellular or extracellular cesium (Cs(+)) and/or extrac...

The effect of barium on Müller cell K+ conductance was evaluated in the tiger salamander using enzymatically dissociated cells and cells in situ (retinal slice and isolated retina). Barium effects were similar in both cases. In dissociated cells, 50 microM Ba2+ depolarized cells 14.7 mV and raised cell input resistance from a control value of 16.0 to 133 M omega. For cells in situ, 50 microM Ba...

BACKGROUND AND PURPOSE Cerebrovascular autoregulation has been described with a phase lead of cerebral blood flow preceding changes in cerebral perfusion pressure (CPP), but there has been less focus on the effect of CPP on cerebral vascular resistance. We investigated these relations during spontaneous fluctuations (control) and repeated head-up tilt. METHODS Eight healthy adults were studie...

The excitability of the leg postural circuit and its response to serotonin (5-HT) were studied in vitro in thoracic nervous system preparations of dominant and subordinate male crayfishes. We demonstrate that the level of spontaneous tonic activity of depressor and levator motoneurons (MNs) (which control downward and upward movements of the leg, respectively) and the amplitude of their resista...

Serotonin (5HT) is an endogenous amine that modifies posture in crustacea. Here, we examined the mechanisms of action of 5HT on the resistance reflex in crayfish legs. This reflex, which counteracts movements imposed on a limb, is based on a negative feedback system formed by proprioceptors that sense joint angle movements and activate opposing motoneurons. We performed intracellular recordings...

The adductor muscles of the pectoral fins of the hatchetfish Gasteropelecus are innervated by bilateral pools of about 40 motoneurons which lie primarily in the first spinal segment. A pair of giant fibers on each side of the medulla send processes ventroposteriorly to the motoneuron pools. Electrophysiological evidence indicates that giant fibers are presynaptic to ipsilateral motoneurons, but...