277 research outputs found

    Robust vector quantization for noisy channels

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    The paper briefly discusses techniques for making vector quantizers more tolerant to tranmsission errors. Two algorithms are presented for obtaining an efficient binary word assignment to the vector quantizer codewords without increasing the transmission rate. It is shown that about 4.5 dB gain over random assignment can be achieved with these algorithms. It is also proposed to reduce the effects of error propagation in vector-predictive quantizers by appropriately constraining the response of the predictive loop. The constrained system is shown to have about 4 dB of SNR gain over an unconstrained system in a noisy channel, with a small loss of clean-channel performance

    Efficient Data Averaging for Spin Noise Spectroscopy in Semiconductors

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    Spin noise spectroscopy (SNS) is the perfect tool to investigate electron spin dynamics in semiconductors at thermal equilibrium. We simulate SNS measurements and show that ultrafast digitizers with low bit depth enable sensitive, high bandwidth SNS in the presence of strong optical background shot noise. The simulations reveal that optimized input load at the digitizer is crucial for efficient spin noise detection while the bit depth influences the sensitivity rather weakly

    New Directions in Subband Coding

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    Two very different subband coders are described. The first is a modified dynamic bit-allocation-subband coder (D-SBC) designed for variable rate coding situations and easily adaptable to noisy channel environments. It can operate at rates as low as 12 kb/s and still give good quality speech. The second coder is a 16-kb/s waveform coder, based on a combination of subband coding and vector quantization (VQ-SBC). The key feature of this coder is its short coding delay, which makes it suitable for real-time communication networks. The speech quality of both coders has been enhanced by adaptive postfiltering. The coders have been implemented on a single AT&T DSP32 signal processo

    Evaluation of inbred lines derived from commercial hybrids and their utilization in developing high yielding field corn (Zea mays L.) hybrids

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    Genetic enhancement and identification of genetically broad-based inbred lines for the development of new hybrids is the pre-requisite for the heterosis breeding. Newly derived 118 inbred lines were evaluated for their morpho-physiological characters in order to identify best suitable male and female parental lines. Total 10 best inbred lines were selected after thorough evaluation of 16 stable inbred lines, identified from the pool of 118 inbred lines. These inbred lines were crossed in line × tester manner, considering three inbred lines as male andrest as female, based on the Specific Combining Ability and General Combining Ability. Hybrids thus obtained were evaluated in two diverse agroclimatic situations and best heterotic hybrids were selected based on their standard heterosis and rank obtained in Duncan's Multiple Range Test analysis. Single location ANOVA for inbred lines and combined ANOVA for hybrids showed that selected inbreds and hybrids were significantly differing from each other. Since, there exists a Genotype × Environment interaction among hybrids, PCA also taken into consideration for giving weight as classification variable for the hybrids. Further, multi-location evaluation of these hybrids is proposed to identify stable hybrids suitable for large scale commercialization

    Genetic variability, combining ability and molecular diversity-based parental line selection for heterosis breeding in field corn (Zea mays L.)

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    Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGBackground: The demand of maize crop is increasing day by day, hence to reduce the production and demand gap, there is a need to extract the high yielding parental lines to improve per se yield of the hybrids, which could help to enhance the productivity in maize crops. Methods and results: The present investigation was carried out to select the best medium maturing inbred lines, among a set of 118 inbred lines. Based on the Duncan multiple range test, out of 118 lines, 16 inbred lines were selected on the basis of its high yield per se and flowering time. The molecular diversity was carried out using SSR markers linked to heterotic QTL and up on diversity analysis it classified selected genotypes in to three distinct groups. Among the selected inbred lines, a wider genetic variability and molecular diversity were observed. A total of 39 test crosses were generated after classifying 16 inbred lines in to three testers and thirteen lines (based on per se grain yield and molecular diversity) and crossing them in line × tester manner. Conclusion: Combining ability analysis of these parental lines showed that female parents, PML 109, PML 110, PML 111, PML 114 and PML 116 showed additive effect for KRN and grain yield, whereas male parents, PML 46, and PML 93 showed epistatic effect for KRN and PML 102 showed epistatic effect for grain yield. The generated information in the present investigation may be exploited for heterosis breeding in filed corn. Key messages To tackle the balanced dietary requirement of Indian population; we focused to enhance the productivity of maize hybrids using genetically broad based, elite, diverse inbred lines. Combination of selection criterion, not only augment the productivity but also improves the quality of hybrid/s

    In-orbit Performance of UVIT on ASTROSAT

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    We present the in-orbit performance and the first results from the ultra-violet Imaging telescope (UVIT) on ASTROSAT. UVIT consists of two identical 38cm coaligned telescopes, one for the FUV channel (130-180nm) and the other for the NUV (200-300nm) and VIS (320-550nm) channels, with a field of view of 28 arcminarcmin. The FUV and the NUV detectors are operated in the high gain photon counting mode whereas the VIS detector is operated in the low gain integration mode. The FUV and NUV channels have filters and gratings, whereas the VIS channel has filters. The ASTROSAT was launched on 28th September 2015. The performance verification of UVIT was carried out after the opening of the UVIT doors on 30th November 2015, till the end of March 2016 within the allotted time of 50 days for calibration. All the on-board systems were found to be working satisfactorily. During the PV phase, the UVIT observed several calibration sources to characterise the instrument and a few objects to demonstrate the capability of the UVIT. The resolution of the UVIT was found to be about 1.4 - 1.7 arcsecarcsec in the FUV and NUV. The sensitivity in various filters were calibrated using standard stars (white dwarfs), to estimate the zero-point magnitudes as well as the flux conversion factor. The gratings were also calibrated to estimate their resolution as well as effective area. The sensitivity of the filters were found to be reduced up to 15\% with respect to the ground calibrations. The sensitivity variation is monitored on a monthly basis. UVIT is all set to roll out science results with its imaging capability with good resolution and large field of view, capability to sample the UV spectral region using different filters and capability to perform variability studies in the UV.Comment: 10 pages, To appear in SPIE conference proceedings, SPIE conference paper, 201

    Salmonella in Indian ready-to-cook poultry: antibiotic resistance and molecular characterization

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    The availability and popularity of processed, ready-to-cook (RTC) poultry products are increasing in India. Though fresh poultry is known to be contaminated with Salmonella, the prevalence of this foodborne pathogen in RTC poultry products is not reported. Eighty-seven chilled and frozen RTC poultry samples of 4 different brands obtained from supermarkets and departmental stores in Mumbai were analyzed for the presence of Salmonella. The prevalence of Salmonella was higher (51%) in chilled RTC samples as compared to the frozen RTC samples (5%). The frozen RTC samples of one brand were free from Salmonella. S. Typhimurium (75.2%) was the most prevalent serovar, followed by S. Enteritidis (23%) and S. Weltevreden (1.7%). A high percentage (81.4%) of the isolates were found to be resistant to 5 or more antibiotics and class 1 integron, which has been shown to confer multi-drug resistance, was detected in 69.9% of the isolates. Multiple antibiotic resistance index of isolates was high (0.6) indicating the indiscriminate use of antibiotics during poultry farming. High genetic diversity was observed among the Salmonella serovars based on Pulsed Field Gel Electrophoresis profiles. Results showed the presence of multi-drug resistant Salmonella serovars in processed, chilled RTC poultry products marketed in Mumbai, India

    TAUVEX: status in 2011

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    We present a short history of the TAUVEX instrument, conceived to provide multi-band wide-field imaging in the ultraviolet, emphasizing the lack of sufficient and aggressive support on the part of the different space agencies that dealt with this basic science mission. First conceived in 1985 and selected by the Israel Space Agency in 1989 as its first priority payload, TAUVEX is fast becoming one of the longest-living space project of space astronomy. After being denied a launch on a national Israeli satellite, and then not flying on the Spectrum X-Gamma (SRG) international observatory, it was manifested since 2003 as part of ISRO's GSAT-4 Indian satellite to be launched in the late 2000s. However, two months before the launch, in February 2010, it was dismounted from its agreed-upon platform. This proved to be beneficial, since GSAT-4 and its launcher were lost on April 15 2010 due to the failure of the carrier rocket's 3rd stage. TAUVEX is now stored in ISRO's clean room in Bangalore with no firm indications when or on what platform it might be launched.Comment: Invited contribution presented at the "UV Universe 2010". Accepted for publication in Astrophysics & Space Scienc
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