6,964 research outputs found

### The VLSI design of a single chip Reed-Solomon encoder

A design for a single chip implementation of a Reed-Solomon encoder is presented. The architecture that leads to this single VLSI chip design makes use of a bit serial finite field multiplication algorithm

### $\tau \to \pi K \nu$ Decay and $\pi K$ Scattering

Using chiral low energy theorems and elastic unitarity assumption, the
$\tau\to\pi K \nu$ decay is investigated. The vector and scalar $\pi K$ form
factors are calculated. It is found that the $\pi K$ spectrum is dominated by
the $K^*$ resonance. By measuring the forward-backward asymmetry, it is shown
that the S wave $\pi K$ phase shift can be determined near the $K^{*}$
resonance region. The calculated branching ratio and resonance parameters are
in good agreement with experiments.Comment: 15 pages, Tex, 6 included figure

### Comparative Analysis Of Zebrafish And Planarian Model Systems For Developmental Neurotoxicity Screens Using An 87-Compound Library

There is a clear need to establish and validate new methodologies to more quickly and efficiently screen chemicals for potential toxic effects, particularly on development. The emergence of alternative animal systems for rapid toxicology screens presents valuable opportunities to evaluate how systems complement each other. In this article, we compare a chemical library of 87-compounds in two such systems, developing zebrafish and freshwater planarians, by screening for developmental neurotoxic effects. We show that the systems’ toxicological profiles are complementary to each other, with zebrafish yielding more detailed morphological endpoints and planarians more behavioral endpoints. Overall, zebrafish was more sensitive to this chemical library, yielding 86/87 hits, compared to 50/87 hits in planarians. The difference in sensitivity could not be attributed to molecular weight, Log Kow or the bioconcentration factor. Of the 87 chemicals, 28 had previously been evaluated in mammalian developmental neuro- (DNT), neuro- or developmental toxicity studies. Of the 28, 20 were hits in the planarian, and 27 were hits in zebrafish. Eighteen of the 28 had previously been identified as DNT hits in mammals and were highly associated with activity in zebrafish and planarian behavioral assays in this study. Only 1 chemical (out of 28) was a false negative in both zebrafish and planarian systems. Differences in endpoint coverage and system sensitivity illustrate the value of a dual systems approach to rapidly query a large chemical-bioactivity space and provide weight-of-evidence for prioritization of chemicals for further testing

### Application of Current Algebra in Three Pseudoscalar Meson Decays of $\tau$ Lepton

The decays of $\tau \to 3\pi \nu$ and $\tau \to \pi K^{*} \nu, K\rho \nu$
are calculated using the hard pion and kaon current algebra and assuming the
Axial-Vector meson dominance of the hadronic axial currents. Using the
experimental data on their masses and widths, the $\tau$ decay branching ratios
into these channels are calculated and found to be in a reasonable agreement
with the experimental data. In particular, using the available Aleph data on
the $3\pi$ spectrum, we determine the $A_1$ parameters, $m_A=1.24\pm 0.02 GeV$,
$\Gamma _A=0.43\pm 0.02$ GeV; the hard current algebra calculation yields a
$3\pi$ branching ratio of $19 \pm 3 \%$.Comment: 14 pages, Tex, 6 included figure

### A Method of Optimal Radio Frequency Assignment for Deep Space Missions

A method for determining optimal radio frequency channels for the Deep Space Network is described. Computer automated routines calculate interference-to-signal ratios over a given mission period and provide a quantitative assessment of the channels which could then be assigned to a new mission. This automated procedure reduces the analysis time considerably and effectively improves upon the accuracy of existing channel assignment techniques

### A VLSI single chip (255,223) Reed-Solomon encoder with interleaver

A single-chip implementation of a Reed-Solomon encoder with interleaving capability is described. The code used was adapted by the CCSDS (Consulative Committee on Space Data Systems). It forms the outer code of the NASA standard concatenated coding system which includes a convolutional inner code of rate 1/2 and constraint length 7. The architecture, leading to this single VLSI chip design, makes use of a bit-serial finite field multiplication algorithm due to E.R. Berlekamp

- …