21,387 research outputs found

    On Computing Shannon’s Sphere Packing Bound and Applications

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    file: :home/zaki/.local/share/data/Mendeley Ltd./Mendeley Desktop/Downloaded/Ahmed, Ambroze, Tomlinson - 2007 - On Computing Shannon’s Sphere Packing Bound and Applications.pdf:pdf keywords: SPB mendeley-tags: SPBA new method to numerically evalu- ate Shannon’s lower bound is presented in this pa- per. This new method is based on the Incomplete Beta function and permits the exact evaluation of the Sphere Packing Bound for a large range of code sizes, rates and probability of error. Comparisons with cur- rent standards (DVB–RCS, DVB–S2 and 3GPP) are also presented and discussed. It is shown that cur- rent standard coding schemes are about 0.6dB from the Shannon Limit corrected for Binary Signalling

    Scotogenic A4A_4 Neutrino Model for Nonzero Ξ13\theta_{13} and Large ΎCP\delta_{CP}

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    Assuming that neutrinos acquire radiative seesaw Majorana masses through their interactions with dark matter, i.e. scotogenic from the Greek 'scotos' meaning darkness, and using the non-Abelian discrete symmetry A4A_4, we propose a model of neutrino masses and mixing with nonzero Ξ13\theta_{13} and necessarily large leptonic CP violation, allowing both the normal and inverted hierarchies of neutrino masses, as well as quasi-degenerate solutions.Comment: 12 pages, 12 figure

    Radiative Scaling Neutrino Mass with A4A_4 Symmetry

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    A new idea for neutrino mass was proposed recently, where its smallness is not due to the seesaw mechanism, i.e. not inversely proportional to some large mass scale. It comes from a one-loop mechanism with dark matter in the loop consisting of singlet Majorana fermions NiN_i with masses of order 10 keV and neutrino masses are scaled down from them by factors of about 10−510^{-5}. We discuss how this model may be implemented with the non-Abelian discrete symmetry A4A_4 for neutrino mixing, and consider the phenomenology of NiN_i as well as the extra scalar doublet (η+,η0)(\eta^+,\eta^0).Comment: 11 pages, 1 figur

    DNA folding and melting observed in real time redefine the energy landscape

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    We report real-time observations of the folding and melting of DNA by probing two active sites of a hairpin structure, the bases and the stem end, and using an ultrafast T-jump. Studies at different initial temperatures (before, during, and after melting) provide the time scale of water heating (<20 ps), single-strand destacking (700 ps to 2 ns), and hairpin destacking (microseconds and longer) in solutions of various ionic strengths and pH values. The behavior of transient changes gives direct evidence to the existence of intermediate collapsed structures, labile in destacking but compact in nature, and indicates that melting is not a two-state process. We propose a landscape that is defined by these nucleation structures and destacking for efficient folding and melting

    Neutral SU(2) Gauge Extension of the Standard Model and a Vector-Boson Dark-Matter Candidate

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    If the standard model of particle interactions is extended to include a neutral SU(2)_N gauge factor, with SU(3)_C x SU(2)_L x U(1)_Y x SU(2)_N embedded in E_6 or [SU(3)]^3, a conserved generalized R parity may appear. As a result, we have the first example of a possible dark-matter candidate X_1 which is a non-Abelain vector boson. Using current data, its mass is predicted to be less than about 1 TeV. The associated Z' of this model, as well as some signatures of the Higgs sector, should then be observable at the LHC (Large Hadron Collider).Comment: 10 pages, 1 figure; version accepted in PL

    Development and performance determination of warm mix asphalt using rap for Malaysian conditions / Frag Ahmed Ma Kridan

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    Current concerns on the scarcity of resources necessitate the road building industry to review its production of asphaltic concrete. The use of Warm Mix Asphalt (WMA) technologies with asphalt mixtures containing reclaimed asphalt pavement (RAP) may provide synergistic advantages. WMA-RAP mixes conserves scarce resources such as aggregates by using RAP as partial replacement of aggregates and reduces the use of energy (reduction in production temperature) by using WMA additives. Most specifications allow not more than 30% RAP as higher percentages of RAP introduces variability in the material properties and produces inconsistencies in asphalt mix properties. The goal of this study was to evaluate the performance of warm mix asphalt with high proportions of RAP (30%, 40% and 50%) and using Sasobit as the warm mix additive to reduce the mixing and compaction temperature

    Distributed Efficient Similarity Search Mechanism in Wireless Sensor Networks

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    The Wireless Sensor Network similarity search problem has received considerable research attention due to sensor hardware imprecision and environmental parameter variations. Most of the state-of-the-art distributed data centric storage (DCS) schemes lack optimization for similarity queries of events. In this paper, a DCS scheme with metric based similarity searching (DCSMSS) is proposed. DCSMSS takes motivation from vector distance index, called iDistance, in order to transform the issue of similarity searching into the problem of an interval search in one dimension. In addition, a sector based distance routing algorithm is used to efficiently route messages. Extensive simulation results reveal that DCSMSS is highly efficient and significantly outperforms previous approaches in processing similarity search queries

    Antidiabetic Efficacy of Aqueous Fruit Extract of Amla (Emblica officinalis, Gaertn) in Streptozotocin-Induced Diabetes Mellitus in Male Rats

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    Purpose: To investigate the antidiabetic potential of Emblica officinalis, Gaertn on diabetic rats.Methods: The study investigated the anti-hyperglycemic potential of the aqueous fruit extract of amla (E. officianalis, for eleven weeks in streptozotocin-induced diabetic obese rats. The study utilized forty eight rats divided into four groups as follows. Untreated diabetic control (group 1) received 2 % gum acacia as vehicle; groups 2 and 3 were diabetic rats administered the fruit extract in 400 and 200 mg/kg doses, respectively; while group 4 (diabetic rats) received metformin (600 mg/kg) as reference drug. The parameters assessed weekly were body weight, as well as fasting blood glucose, cholesterol and triglyceride levels in venous blood.Results: Both plant extract-treated groups showed significant (p ≀ 0.001) reduction in blood glucose levels in the fifth and sixth weeks compared to the metformin-treated group. Body weight significantly increased during the fourth, fifth and sixth weeks, being more pronounced in the extract-treated groups (272 ± 15.0 g and 227 ± 7.23 g for 200 and 400 mg/kg doses, respectively; the corresponding body weight for untreated diabetic control was 197 ± 9.83 g. Furthermore, both extract doses (200 and 400 mg/kg) produced significant decrease (p ≄ 0.05) in serum glucose (186 ± 15.5 mg/L and 146 ± 15.1 mg/L), cholesterol (143.6 ± 0.86 mg/L and 151.0 ± 0.77mg/L) and triglyceride (82.6 ± 0.51mg/dl and 84.8 ± 0.84 m/dl) levels, respectively, similar to the metformin treated group.Conclusion: The anti-diabetic activity of the aqueous extract of E. officianalis used showed a better potential than metformin.Keywords: Antidiabetic, Emblica officianalis fruit, Obesity, Glucose, Cholesterol, Triglyceride
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