[en] Short communication

[en] In vitro addition of 16,16'-dimethyl prostaglandin E₂ to Golgi-rich membrane fraction in final concentration of 0.1 μg/1 mg of protein increased generally the activity of galactosyltransferase in comparison with control. The percentage of phospholipids in the whole fraction was similar in both investigated groups, only the sum of phosphatidylenoamine + phosphatidic acid was significantly lower after addition of dmPGE₂ than in the control (0.001 < P < 0.01). (author). 25 refs, 2 figs, 1 tab

[en] In this paper the overvoltage protection modules (OVP) for the power supply (PS) system of the Belle II pixel detector (PXD) are described. The aim of the OVP is to protect the detector and associated electronics against overvoltage conditions. Most critical in the system are voltages supplying the front-end ASICs. The PXD detector consists of the DEPFET sensor modules with integrated chips like the Drain Current Digitizer, the Switcher and the Data Handling Processor. These chips, implemented in modern sub-micron technologies, are quite vulnerable to variations in the supply voltages. The PXD will be placed in the Belle II experiment as close as possible to the interaction point, where access during experiment is very limited or even impossible, thus the PS and OVP systems exploit the remote-sensing method. Overvoltage conditions are due to failures of the PS itself, wrong setting of the output voltages or transient voltages coming out of hard noisy environment of the experiment. The OVP modules are parts of the PS modules. For powering the PXD 40 PS modules are placed 15 m outside the Belle II spectrometer. Each one is equipped with the OVP board. All voltages (22) are grouped in 4 domains: Analog, Digital, Steering and Gate which have independent grounds. The OVP boards are designed from integrated circuits from Linear Technology. All configurations were simulated with the Spice program. The control electronics is designed in a Xilinx CPLD. Two types of integrated circuits were used. LT4356 surge stopper protects loads from high voltage transients. The output voltages are limited to a safe value and also protect loads against over current faults. For less critical voltages, the LTC2912 voltage monitors are used that detect under-voltage and overvoltage events. It has to be noted that the OVP system is working independently of any other protection of the PS system, which increases its overall reliability. (authors)

[en] In the procedure of double dimensional reduction that produces a string theory from a membrane theory in one higher spacetime dimension, the conformal invariance of the string is shown to have its origin in the worldvolume diffeomorphism invariance of the membrane theory. In order to obtain this result, the ansatz for the dimensional reduction must be written in a differential form that leaves the conformal factor as an 'integration constant' of the ansatz. (orig.)

[en] The authors describe a general purpose 40MHz pipelined trigger processing board containing six look-up tables and the logic needed to programmably route the signals between them. A series of identical boards are connected in cascade in the NA48 CP-violation experiment at CERN, accept digital inputs generated from calorimeter signals and are used to perform the different computations necessary for the trigger reconstruction. The board architecture is designed to be flexible so that a single basic hardware design can perform all the different algorithms they require and so that the trigger algorithms can be adapted if needed. The computation latency of the combined network of eight boards is approximately 3 micros. They present examples of some of the functions which have been implemented. They discuss the automatic reprogramming software which has been developed so that a new design can be implemented easily

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