48,995 research outputs found

    Signal Detection for QPSK Based Cognitive Radio Systems using Support Vector Machines

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    Cognitive radio based network enables opportunistic dynamic spectrum access by sensing, adopting and utilizing the unused portion of licensed spectrum bands. Cognitive radio is intelligent enough to adapt the communication parameters of the unused licensed spectrum. Spectrum sensing is one of the most important tasks of the cognitive radio cycle. In this paper, the auto-correlation function kernel based Support Vector Machine (SVM) classifier along with Welch's Periodogram detector is successfully implemented for the detection of four QPSK (Quadrature Phase Shift Keying) based signals propagating through an AWGN (Additive White Gaussian Noise) channel. It is shown that the combination of statistical signal processing and machine learning concepts improve the spectrum sensing process and spectrum sensing is possible even at low Signal to Noise Ratio (SNR) values up to -50 dB

    Design and Focused Ion Beam Fabrication of Single Crystal Diamond Nanobeam Cavities

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    We present the design and fabrication of nanobeam photonic crystal cavities in single crystal diamond for applications in cavity quantum electrodynamics. First, we describe three-dimensional finite-difference time-domain simulations of a high quality factor (Q ~ 10^6) and small mode volume (V ~ 0.5 ({\lambda}/n)^3) device whose cavity resonance corresponds to the zero-phonon transition (637nm) of the Nitrogen-Vacancy (NV) color center in diamond. This high Q/V structure, which would allow for strong light-matter interaction, is achieved by gradually tapering the size of the photonic crystal holes between the defect center and mirror regions of the nanobeam. Next, we demonstrate two different focused ion beam (FIB) fabrication strategies to generate thin diamond membranes and nanobeam photonic crystal resonators from a bulk crystal. These approaches include a diamond crystal "side-milling" procedure as well as an application of the "lift-off" technique used in TEM sample preparation. Finally, we discuss certain aspects of the FIB fabrication routine that are a challenge to the realization of the high-Q/V designs

    Biological activities of aerial parts of Paeonia emodi wall

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    The ethanolic extract derived from the aerial parts of Paeonia emodi was screened for various in vitro biological activities including antifungal, antibacterial, insecticidal, phytotoxic and haemagglutination activities. General toxicity (brine shrimp lethality assay) of this extract has also been assessed. The extract was found to possess excellent phytotoxicity against Lemna minor L., moderate heamagglutination activity against human erythrocytes and reasonable insecticidal activity against Bruchus pisorum. The crude extract did not display any antifungal or antibacterial activity against the fungi and bacteria used in this study. No significant general toxicity was observed with the extract at tested concentrations

    Marine fish calendar. 3. Calicut

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    The article provides the fish landing details at Calicut during 1981 to 1986. Majority of the landing were contributed by the indigenous gears like boat seines, drift net, hooks and line and gill net. Major group of fish landed includes clupeids, anchovies, seer fishes, mackerel and tunas, soles, cat fishes, pomfrets and elasmobranchs

    Correlates of socioeconomic status and the health of older people in the United Kingdom: a review

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    This paper reviews the existing literature on the association between the socio-economic status (SES) and the health of the ageing population in the United Kingdom (UK). It has been noted that socio-economic differentials are more marked across the UK than they are in other developed countries. Social class gradients are significant in health for working age people (up to age 65), whereas studies on older populations have so far been limited so as to draw any robust conclusions. In this paper, we examine the inequalities through selected SES indicators in order to tease out the effects on health outcomes of the older population. We critically review the physical and mental health indicators of older people in the UK with regard to their SES differentials. The findings reveal that older people with lower SES are more likely to experience poorer health outcomes (for example, long-standing illness or increased disability) and have shorter life expectancy compared to those of higher SES. We illustrate how education remains the single most important determinant of health inequality in later life. We suggest that educational level or occupational class allied with material deprivation offer the best combined indicators of SES for studying health inequalities among older people. The findings of this paper has profound implications for prioritising policies to improve the health and wellbeing of elderly people with lower SES and go offer an evidence base of how to understand and to develop interventions that minimise the inequalities in health in later life in the UK

    COMPARATIVE EFFICACY OF FIVE DIFFERENT BRANDS OF COMMERCIAL NEWCASTLE DISEASE LASOTA VIRUS VACCINES IN BROILERS

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    Five commercial LaSota strain Newcastle disease (ND) vaccines namely A, B, C, D and E were evaluated for their potency, efficacy, thermostability and influence on productivity in broilers. A 3-log10 difference of EID50 and two-to-eight fold difference of HA activity was found among the various vaccines tested. One hundred and fifty day-old broiler chicks were divided into six equal groups tagged as I, II, III, IV, V and VI. The birds in groups I, II, III, IV and V were actively immunized against ND on days 7 (eye drop method) and 21 (drinking water) using vaccines A, B, C, D and E, respectively. The birds in group VI served as unvaccinated control. The serum HI antibody response to five vaccines was determined 7, 14, 21 and 28 days post-vaccination. Fifteen birds from each group including unvaccinated control were challenged at day 35 with local virulent ND field isolate. The HI serum antibody profile and post-challenge mortality pattern revealed a dose-response relation between the virus content, humoral antibody response and clinical protection. To compare the heat stability, the vaccines were incubated at 4, 25 and 400C for a period of 24 hours. There was no remarkable reduction in HA titer, however slight dips (less than 2 logarithmic units) in EID50 values were found in all the vaccines. All the vaccines caused significant suppression in weight gain, leading to a poor performance in terms of feed conversion ratio (FCR) and European Efficiency Factor (EEF)

    Sensitive Coverage Saves Lives: Improving media portrayal of suicidal behaviour

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    The report outlines the results of consultations with journalists, suicide prevention agencies and mental health groups conducted by the journalism ethics charity MediaWise. It makes recommendations for action by media organisations and suicide prevention agencies

    Chiral symmetry and the axial nucleon to Delta(1232) transition form factors

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    We study the momentum and the quark mass dependence of the axial nucleon to Delta(1232) transition form factors in the framework of non-relativistic chiral effective field theory to leading-one-loop order. The outcome of our analysis provides a theoretical guidance for chiral extrapolations of lattice QCD results with dynamical fermions.Comment: 18 pages, 3 figure
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