253 research outputs found

    A STUDY OF A FUCHSIAN SYSTEM OF RANK 8 IN 3 VARIABLES AND THE ORDINARY DIFFERENTIAL EQUATIONS AS ITS RESTRICTIONS

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    A Fuchsian system of rank 8 in 3 variables with 4 parameters is found. The singular locus consists of six planes and a cubic surface. The restriction of the system onto the intersection of two singular planes is an ordinary differential equation of order four with three singular points. A middle convolution of this equation turns out to be the tensor product of two Gauss hypergeometric equations, and another middle convolution sends this equation to the Dotsenko-Fateev equation. Local solutions of these ordinary differential equations are found. Their coefficients are sums of products of the Gamma functions. These sums can be expressed as special values of the generalized hypergeometric series ₄F₃ at 1

    Steady-state data acquisition method for LHD diagnostics

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    The LHD experiment has gone through 5 campaign periods over the past 4 years, during which the diagnostics data continues to grow and the primary 28 measurements produce about 620 MB/shot in 150 shot/day 3-min cycles. In 2002, 30-min long-pulse experiments will be carried out in LHD, where real-time operations are indispensable for plasma measurements and data acquisition. The new scheme for utilizing conventional CAMAC digitizers in long-pulse experiments has been discussed and examined. As a result, in LHD, CAMACs will shift into 120?180 s cyclic operation, synchronized by the diagnostic timing system. The new CompactPCI-based digitizer frontend has performed about 84 MB/s continuous acquisition in benchmarks, and has been formulated with the conventional CAMAC system to make concurrent acquisitions

    FUNDAMENTAL HEAT TRANSFER EXPERIMENTS OF HEAT PIPES FOR TURBINE COOUNG

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    ABSTRACT Fundamental heat transfer experiments were carried out for three kinds of heat pipes which may be applied to turbine cooling in future aero-engines. In the turbine coaling system with a heat pipe, heat transfer rate and start-up time of the heat pipe are the most important performance criteria to evaluate and compare with conventional cooling methods. Three heat pipes are considered, called heat pipe A, B and C, respectively. All heat pipes have a stainless steel shell and nickel sintered powder metal wick. Sodium(Na) was the working fluid for heat pipes A and B; heat pipe C used eutectic sodiumpotassium(NaK). Heat pipes B and C included non-condensible gas for rapid start-up. There were fins on the cooling section of heat pipes. In the experiments, an infrared image furnace supplied heat to the beat pipe simulating turbine blade surface conditions. In the results, heat pipe B demonstrated the highest heat flux of 17 to 20 W/cm 2. The start-up time was about 6 minutes for heat pipe B and about 16 minutes for heat pipe A. Thus adding non-condensible gas effectively reduced start-up time. Although NaK is a liquid phase at room temperature, the start-up time of heat pipe C (about 7 to 8 minutes) was not shorter than the heat pipe B. The effect of a gravitational force on heat pipe performance was also estimated by inclining the heat pipe at an angle of 90 degrees. There was no significant gravitational dependence on heat transport for heat pipes including non-condensible gas

    Echocardiographic Features and Cardiac Motion in Electrical Alternans

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    A 54-year-old female with adenocarcinoma of the lung developed cardiac tamponade. An electrocardiogram revealed electrical alternans of QRS complex. An echocardiogram demonstrated a large pericardial effusion and pendulous motion of the left atrium as well as of the left ventricle. Echocardiographic features of cardiac tamponade and mechanism of electrical alternans were also discussed

    Control of synaptic transmission in the CNS through endocannabinoid-mediated retrograde signaling

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    Psychological and physiological effects of marijuana are caused by binding of its active component (Δ9-tetrahydrocannabinol) to cannabinoid receptors. The cannabinoid receptors belong to a family of G protein-coupled seven-transmembrane-domain receptors, and consist of type 1 (CBl) and type 2 (CB2) receptors with different distributions (Matsuda et al., 1990; Munro et al., 1993; Felder and Glass, 1998). The CBl receptor is expressed in the CNS, whereas the CB2 receptor is found in the immune system of the periphery (Klein et al., 1998). Activation of the CBl receptor induces various effects on neural functions (Di Marzo et al, 1998; Felder and Glass, 1998), including suppression of neurotransmitter release (Gifford and Ashby, 1996; Ishac et al., 1996; Shen et al., 1996; Katona et al, 1999; Hoffman and Lupica, 2000). Several molecules are identified as candidate endogenous ligands for cannabinoid receptors (endocannabinoids). Arachidonylethanolamide (anandamide) and 2-arachidonoylglycerol (2-AG), two major endocannabinoids, are reported to be synthesized from membrane phospholipids in an activity- and a Ca2+-dependent manner (Cadas et al, 1996; Stella et al, 1997; Di Marzo et al, 1998; Bisogno et al, 1999; PiomeUi et al, 2000). It is thought that they can diffuse out across the cell membrane. The released endocanabinoids are removed from the extracellular space through uptake and enzymatic degradation (Mechoulam et al, 1998). All these findings suggest that endocannabinoids can work as a diffusible and short-lived mediator that is released from activated neurons, binds to cannabinoid receptors on neighboring neurons to modulate their functions. Recent electrophysiological studies have revealed that endocannabinoids play an important role in retrograde modulation of synaptic transmission in the CNS (Kreitzer and Regehr, 2001b; Maejima et al, 2001a; Ohno-Shosaku et al, 2001; Wilson and NicoU, 2001). Endocannabinoids are released from postsynaptic neurons in response to either depolarization or activation of Gq/11-coupled receptors such as group I metabotropic glutamate receptors (mGluRs) and M1/M3 muscarinic acetylcholine receptors. The released endocannabinoids then activate presynaptic cannabinoid receptors and suppress transmitter release (Maejima et al, 2001b; Alger, 2002; Kano et al, 2002; Kreitzer and Regehr, 2002; Wilson and Nicoll, 2002; Freund et al, 2003; Kano et al., 2003; PiomelU, 2003). Thus, the endocannabinoid signaling is an important mechanism by which postsynaptic neuronal activity can retrogradely influence presynaptic functions. In this review, we introduce recent electrophysiological studies on endocannabinoidmediated retrograde modulation and discuss its possible physiological roles in the CNS.Dendritic neurotransmitter release, edited by Mike Ludwig, Springer, c2005, 269-281, (A part of the memoirs
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