New version of an instrument for measuring the sun's height by means of a ring laser

An instrument is proposed for continuously tracking the Sun and measuring its height by the use of a laser gyrometer as measuring converter. The accuracy in photoelectric sighting on the Sun is improved by greatly reducing the light fluxes to be compared by screening out the central part of the Sun's image in the focal plane. Translated from Izmeritel'naya Tekhnika, No. 3, pp. 7–9, March, 1994.     

Effects of error variation in means of measurement on reliability parameters in engineering-system monitoring

A method is given for calculating the monitoring reliability parameters (MRP) for an engineering system with allowance for the drift in the measurement error of the means of measurement (MM). The approach is based on introducing a biased MM error distribution into the traditional formulas for the conditional probabilities of spurious and unobserved failure. The bias at the center of the distribution is determined by the systematic error at the given instant. An example is given to illustrate the performance in MRP calculation.Translated from Izmeritel'naya Tekhnika, No. 1, pp. 12–13, January, 1994.     

Filter matrix estimation in automated DNA sequencing

In four-color fluorescence-based automated DNA sequencing, a 4×4 filter matrix parameterizes the relationship between the dye-intensity signals of interest and the data collected by an optical imaging system. The filter matrix is important because the estimated DNA sequence is based on the dye intensities that can only be recovered via inversion of the matrix. Here, the authors present a calibration method for the estimation of the columns of this matrix, using data generated through a special experiment in which DNA samples are labeled with only one fluorescent dye at a time. Simulations and applications of the method to real data are provided, with promising results     

The effects of cholecystokinin A and B receptor antagonists, devazepide and L 365260, on citalopram-induced decrease of exploratory behaviour in rat

The present study has been divided into two sets. In the first set, the aim of the experiments was to investigate the dose-response effect of selective serotonin re-uptake inhibitor (SSRI) citalopram on rat exploratory behaviour in the elevated plus-maze. In the second set of experiments, the effect of cholecystokinin (CCK) CCKA and CCKB receptor antagonists, devazepide and L 365260, on citalopram-induced decrease of exploratory behaviour in the elevated plus-maze was studied. Citalopram (5 and 10 mg/kg) decreased the number of open and total arm entries, line crossings on open arms, and percentage of time spent exploring in open arm. Dose 15 mg/kg was without any effect on rat exploratory behaviour. Devazepide (0.01 and 1.0 mg/kg) failed to modify any of the citalopram-induced changes observed. L 365260 (1.0 mg/kg) reversed most of the effects of citalopram: the numbers of open and total arm entries, the number of line crossings, and the percentage of time spent exploring in open arms. L 365260 at dose level 0.01 mg/kg was ineffective. These results support the involvement of the CCKB receptor subtype in SSRI-induced anxiogenic-like effects in rodents.     

Equations of the oscillations of a deep massive foundation flexibly restrained in the ground

A new equation is derived for the rotational oscillations of a deep massive foundation flexibly restrained in the ground. An error in the corresponding equation published in the literature is indicated. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 7–8, November–December, 1996.     

Capacity enhancement of cellular CDMA by traffic-based control ofspeech bit rate

Variable rate speech coding is now recognized as an important system component for high-capacity cellular networks because it exploits speech statistics to reduce the average bit rate, which results in reduced interference and increased capacity. Once a variable rate capability is available, an additional capacity enhancement can be achieved by introducing network control of the user bit rate in response to changing traffic levels. We introduce the concept of network control of rate and propose a particular network-control method for code-division multiple access (CDMA) systems. Based on an M/M/∞//M queueing model applied to a cell under heavy traffic conditions and a new performance measure called averaged speech quality, we obtain simulation results to demonstrate how network control of rate can achieve improved speech quality or increased capacity for a given quality objective     

Poly(A) metabolism in Xenopus laevis embryos: substrate-specific and default poly(A) nuclease activities are mediated by two distinct complexes

The metabolism of the poly(A) tail is a process important for the translational regulation of maternal mRNAs in Xenopus laevis oocytes and early embryos. Two poly(A) nuclease (PAN) activities have been described in Xenopus embryo or activated egg extracts (Legagneux et al (1995) RNA 1, 1001-1008). These activities (default PAN and EgPAN) are distinguishable by their deadenylation kinetics and their substrate specificities. In this report, we show that these activities display different sensitivities to biochemical treatments. Urea and, to a lesser extent, spermidine, inhibit EgPAN at concentrations which have no effect on default PAN. Heparin activates default PAN but inhibits EgPAN. When extracts are fractionated by ultracentrifugation, the default activity is recovered in one unique fraction, whereas two fractions must be combined to reconstitute the EgPAN activity. Moreover, these two deadenylation activities are separable by size exclusion chromatography under native conditions. We conclude that these two deadenylation activities are mediated by two protein complexes.