6,388 research outputs found

    Simple system to measure the Earth's magnetic field

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    Our aim in this proposal is by using the Faraday's law of induction as a simple lecture demonstration to measure the Earth's magnetic field (B). This will also enable the students to learn about how electric power is generated from the rotational motion. Obviously the idea is not original, yet it may be attractive in the sense that no sophisticated devices are used

    Negative differential Rashba effect in two-dimensional hole systems

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    We demonstrate experimentally and theoretically that two-dimensional (2D) heavy hole systems in single heterostructures exhibit a \emph{decrease} in spin-orbit interaction-induced spin splitting with an increase in perpendicular electric field. Using front and back gates, we measure the spin splitting as a function of applied electric field while keeping the density constant. Our results are in contrast to the more familiar case of 2D electrons where spin splitting increases with electric field.Comment: 3 pages, 3 figures. To appear in AP

    Social media usage in academic research

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    Recently researchers have used “conversation prism” and “social media prisma”, to consolidate social medias with respect to their use. Although both identified 25 types, having average five examples each, they did not identify contribution of each type in academic research. Moreover some of mentioned social services had been suspended or changed. In this paper we attempt to access each social media mentioned in conversation prism in order to first, identify services that are operational to date, services which have suspended and those which have changed during course of time. Second, we compare number of publications associated with each social media, in order to identify which social media has contributed most to academic research. Third, we attempt to find correlation between number of publications and development tools provided by respective social applications. Fourth, social medias are ranked with respect to number of times other social medias share content with respective social application. It was found that out of 168 social applications, 10% changed their service objective while 13% were suspended. Among all social application, AMAZON had highest i.e. 147,000 number of citations on Google scholar whereas 90.7% of total citations were contributed by top 30 social medias. For developers, 22 out of top 30 social medias provided developer options in form of either application programming interface (API) or software development kits (SDK) and Facebook was found to be most cross referred social media based on content sharing. Finally conclusion and future work of study is presented

    An Adaptive Energy Efficient Reliable Routing Protocol for Wireless Sensor Network

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    Wireless sensor networks are networks of tiny sensing devices for communicating in using wireless technology. Wireless sensor networks are deployed in scenarios where any plant information should be available for industrial control applications. Cross-layer interaction is most important factor to gain maximum efficiency and also able to provide difficult interaction among the layers of the protocol stack. Hence to achieve this is challenging issue because latency, energy and reliability are at odds, and also resource constrained does not support complex algorithm. Wireless sensor networks have many protocols. In this paper Breath protocol is proposed for industrial control application .To minimizing energy consumption in network breath is designed for WSNs by which nodes attached to plants must carry information via through multi hop routing to sink. To optimize energy efficiency the protocol is based on randomized routing, medium access control, and duty-cycling. Alternate model of breath protocol ensures a long lifetime of the network by making effective distribution of workload in sensor nodes. Hence it shows as a good terminology for efficient, timely data gathering for industrial control applications. DOI: 10.17762/ijritcc2321-8169.15032

    Dilatonic interpolation between Reissner-Nordstrom and Bertotti-Robinson spacetimes with physical consequences

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    We give a general class of static, spherically symmetric, non-asymptotically flat and asymptotically non-(anti) de Sitter black hole solutions in Einstein-Maxwell-Dilaton (EMD) theory of gravity in 4-dimensions. In this general study we couple a magnetic Maxwell field with a general dilaton potential, while double Liouville-type potentials are coupled with the gravity. We show that the dilatonic parameters play the key role in switching between the Bertotti-Robinson and Reissner-Nordstr\"om spacetimes. We study the stability of such black holes under a linear radial perturbation, and in this sense we find exceptional cases that the EMD black holes are unstable. In continuation we give a detailed study of the spin-weighted harmonics in dilatonic Hawking radiation spectrum and compare our results with the previously known ones. Finally, we investigate the status of resulting naked singularities of our general solution when probed with quantum test particles.Comment: 27 pages, 4 figures, to appear in CQG

    Periodic Instantons in SU(2) Yang-Mills-Higgs Theory

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    The properties of periodic instanton solutions of the classical SU(2) gauge theory with a Higgs doublet field are described analytically at low energies, and found numerically for all energies up to and beyond the sphaleron energy. Interesting new classes of bifurcating complex periodic instanton solutions to the Yang-Mills-Higgs equations are described.Comment: 11 pages, 3 figures (in 5 included eps files), ReVTeX (minor typos corrected and reference added

    Parental [correction of Perinatal] consanguinity: a risk factor for developmental delay in Pakistani children

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    Objective: To investigate the association of parental consanguinity and delayed development in terms of gross motor, fine motor, speech and social aspects in their children.Methods: One hundred and seventy seven children (age 15 days--72 months) were evaluated for their developmental status utilizing the Denver Developmental Screening Test (DDST). An unmatched case-control study design was used. Case group consisted of 94 children and control group 83 children. Odds ratios were calculated for parental consanguinity and delay in gross and fine motor, speech and social development in their children, for cases and controls, utilizing Binary Multiple Logistic Regression Analysis. Acquired delay was excluded through detailed birth history in both cases and control group respectively.Results: Univariate analysis showed high significant Odds ratios for all areas of developmental delay (viz. gross and fine motor, speech and social development), between cases and controls (p \u3c .001). At the multivariate analysis level however, our results showed no increased risk of parental consanguinity on delayed gross and fine motor, speech and social development in their children.Conclusion: Our results show no increased risk of parental consanguinity on delayed gross and fine motor, speech or social development (as measured by the DDST), in their children

    Stochastic approach to inflation II: classicality, coarse-graining and noises

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    In this work we generalize a previously developed semiclassical approach to inflation, devoted to the analysis of the effective dynamics of coarse-grained fields, which are essential to the stochastic approach to inflation. We consider general non-trivial momentum distributions when defining these fields. The use of smooth cutoffs in momentum space avoids highly singular quantum noise correlations and allows us to consider the whole quantum noise sector when analyzing the conditions for the validity of an effective classical dynamical description of the coarse-grained field. We show that the weighting of modes has physical consequences, and thus cannot be considered as a mere mathematical artifact. In particular we discuss the exponential inflationary scenario and show that colored noises appear with cutoff dependent amplitudes.Comment: 18 pages, revtex, no figure

    Stochastic Inflation:The Quantum Phase Space Approach

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    In this paper a quantum mechanical phase space picture is constructed for coarse-grained free quantum fields in an inflationary Universe. The appropriate stochastic quantum Liouville equation is derived. Explicit solutions for the phase space quantum distribution function are found for the cases of power law and exponential expansions. The expectation values of dynamical variables with respect to these solutions are compared to the corresponding cutoff regularized field theoretic results (we do not restrict ourselves only to \VEV{\F^2}). Fair agreement is found provided the coarse-graining scale is kept within certain limits. By focusing on the full phase space distribution function rather than a reduced distribution it is shown that the thermodynamic interpretation of the stochastic formalism faces several difficulties (e.g., there is no fluctuation-dissipation theorem). The coarse-graining does not guarantee an automatic classical limit as quantum correlations turn out to be crucial in order to get results consistent with standard quantum field theory. Therefore, the method does {\em not} by itself constitute an explanation of the quantum to classical transition in the early Universe. In particular, we argue that the stochastic equations do not lead to decoherence.Comment: 43 page

    The Nonlinear Cosmological Matter Power Spectrum with Massive Neutrinos I: The Halo Model

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    Measurements of the linear power spectrum of galaxies have placed tight constraints on neutrino masses. We extend the framework of the halo model of cosmological nonlinear matter clustering to include the effect of massive neutrino infall into cold dark matter (CDM) halos. The magnitude of the effect of neutrino clustering for three degenerate mass neutrinos with m_nu=0.9 eV is of order ~1%, within the potential sensitivity of upcoming weak lensing surveys. In order to use these measurements to further constrain--or eventually detect--neutrino masses, accurate theoretical predictions of the nonlinear power spectrum in the presence of massive neutrinos will be needed, likely only possible through high-resolution multiple particle (neutrino, CDM and baryon) simulations.Comment: v2: matches PRD versio
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