Error Propagation in the Hypercycle

We study analytically the steady-state regime of a network of n error-prone self-replicating templates forming an asymmetric hypercycle and its error tail. We show that the existence of a master template with a higher non-catalyzed self-replicative productivity, a, than the error tail ensures the stability of chains in which m<n-1 templates coexist with the master species. The stability of these chains against the error tail is guaranteed for catalytic coupling strengths (K) of order of a. We find that the hypercycle becomes more stable than the chains only for K of order of a2. Furthermore, we show that the minimal replication accuracy per template needed to maintain the hypercycle, the so-called error threshold, vanishes like sqrt(n/K) for large K and n<=4

Finding the Higgs Boson through Supersymmetry

The study of displaced vertices containing two b--jets may provide a double discovery at the Large Hadron Collider (LHC): we show how it may not only reveal evidence for supersymmetry, but also provide a way to uncover the Higgs boson necessary in the formulation of the electroweak theory in a large region of the parameter space. We quantify this explicitly using the simplest minimal supergravity model with bilinear breaking of R-parity, which accounts for the observed pattern of neutrino masses and mixings seen in neutrino oscillation experiments.Comment: 7 pages, 7 figures. Final version to appear at PRD. Discussion and results were enlarge

White Dwarfs In Ngc6397 And M4: Constraints On The Physics Of Crystallization

We explore the physics of crystallization in the dense Coulomb plasma of the deep interiors of white dwarf stars using the color-magnitude diagram and luminosity function constructed from Hubble Space Telescope photometry of the globular cluster M 4 and compare it with our results for proper motion cleaned Hubble Space Telescope photometry of the globular cluster NGC 6397. We demonstrate that the data are consistent with a binary mixture of carbon and oxygen crystallizing at a value of Gamma higher than the theoretical value for a One Component Plasma (OCP). We show that this result is in line with the latest Molecular Dynamics simulations for binary mixtures of C/O. We discuss implications for future work.Astronom

Long-distance entanglement and quantum teleportation in XX spin chains

Isotropic XX models of one-dimensional spin-1/2 chains are investigated with the aim to elucidate the formal structure and the physical properties that allow these systems to act as channels for long-distance, high-fidelity quantum teleportation. We introduce two types of models: I) open, dimerized XX chains, and II) open XX chains with small end bonds. For both models we obtain the exact expressions for the end-to-end correlations and the scaling of the energy gap with the length of the chain. We determine the end-to-end concurrence and show that model I) supports true long-distance entanglement at zero temperature, while model II) supports {\it ``quasi long-distance''} entanglement that slowly falls off with the size of the chain. Due to the different scalings of the gaps, respectively exponential for model I) and algebraic in model II), we demonstrate that the latter allows for efficient qubit teleportation with high fidelity in sufficiently long chains even at moderately low temperatures.Comment: 9 pages, 6 figure

Alfalfa Response to Phosphorus Sources Associated with the Application of Liming and Gypsum-Shoot Numbers

Alfalfa (Medicago sativa L.) was grown in a Typic Mapluolox soil with triple superphosphate (TS), Gafsa phosphate (GP) and GP with gypsum (GP + G). Three rates of phosphorus application were used 50, 100 and 200 mg P dm-3, before and after liming. Alfalfa was harvested three times. Basal and axillary shoot numbers in alfalfa increased with increasing phosphorus rates. Shoots were produced in higher number with GP in comparison with TS. GP + G resulted in higher basal shoot number than GP. However, there was no gypsum effect on axillary shoot numbers. Liming before or after TS, GP and GP + G application had similar responses on shoot numbers

Probing Neutrino Oscillations in Supersymmetric Models at the Large Hadron Collider

The lightest supersymmetric particle may decay with branching ratios that correlate with neutrino oscillation parameters. In this case the CERN Large Hadron Collider (LHC) has the potential to probe the atmospheric neutrino mixing angle with sensitivity competitive to its low-energy determination by underground experiments. Under realistic detection assumptions, we identify the necessary conditions for the experiments at CERN's LHC to probe the simplest scenario for neutrino masses induced by minimal supergravity with bilinear R parity violation.Comment: 11 pages, 6 figures. To appear in Physical Review

Determining R-parity violating parameters from neutrino and LHC data

In supersymmetric models neutrino data can be explained by R-parity violating operators which violate lepton number by one unit. The so called bilinear model can account for the observed neutrino data and predicts at the same time several decay properties of the lightest supersymmetric particle. In this paper we discuss the expected precision to determine these parameters by combining neutrino and LHC data and discuss the most important observables. We show that one can expect a rather accurate determination of the underlying R-parity parameters assuming mSUGRA relations between the R-parity conserving ones and discuss briefly also the general MSSM as well as the expected accuracies in case of a prospective e+ e- linear collider. An important observation is that several parameters can only be determined up to relative signs or more generally relative phases.Comment: 13 pages, 13 figure

FLAME PROFILE IN A POROUS RADIANT BURNER USING 1/2” AND 1/4” ALUMINA’S SPHERES

Porous burners are known by their high efficiency and low polluting gases emissions. Their high efficiency is given by the great thermal radiation potential, whereas differently a normal burner, the process of combustion happens in the inner of the porous medium, which is compound by spheres of alumina, and the mix air-fuel goes through the preheating zone, potentializing the combustion. The burners are usually used in the industry, in the process of drying of paper and wood, plastic coating, food cooking and ambient heating. In this article, it was studied the behaviour of the flame in a porous radiant burner with alumina’s sphere of 1/2” and 1/4”, using LPG as fuel, compressed air as oxidizing agent and ceramic wool as thermal insulation. The burner was divided in three essential sections with a type K thermocouple in each one, which are: base, middle and top. The flame profile encountered was a floating one, however it is almost stable, presenting low variations of temperature and according to previously tests, less consuming of fuel

Probing neutrino mass with multilepton production at the Tevatron in the simplest R-parity violation model

We analyze the production of multileptons in the simplest supergravity model with bilinear violation of R parity at the Fermilab Tevatron. Despite the small R-parity violating couplings needed to generate the neutrino masses indicated by current atmospheric neutrino data, the lightest supersymmetric particle is unstable and can decay inside the detector. This leads to a phenomenology quite distinct from that of the R-parity conserving scenario. We quantify by how much the supersymmetric multilepton signals differ from the R-parity conserving expectations, displaying our results in the $m_0 \otimes m_{1/2}$ plane. We show that the presence of bilinear R-parity violating interactions enhances the supersymmetric multilepton signals over most of the parameter space, specially at moderate and large $m_0$.Comment: 26 pages, 23 figures. Revised version with some results corrected and references added. Conclusions remain the sam