Co-evolution of RDF Datasets

Linking Data initiatives have fostered the publication of large number of RDF datasets in the Linked Open Data (LOD) cloud, as well as the development of query processing infrastructures to access these data in a federated fashion. However, different experimental studies have shown that availability of LOD datasets cannot be always ensured, being RDF data replication required for envisioning reliable federated query frameworks. Albeit enhancing data availability, RDF data replication requires synchronization and conflict resolution when replicas and source datasets are allowed to change data over time, i.e., co-evolution management needs to be provided to ensure consistency. In this paper, we tackle the problem of RDF data co-evolution and devise an approach for conflict resolution during co-evolution of RDF datasets. Our proposed approach is property-oriented and allows for exploiting semantics about RDF properties during co-evolution management. The quality of our approach is empirically evaluated in different scenarios on the DBpedia-live dataset. Experimental results suggest that proposed proposed techniques have a positive impact on the quality of data in source datasets and replicas.Comment: 18 pages, 4 figures, Accepted in ICWE, 201

Study of the lepton flavor-violating Z′→τμZ'\to\tau\mu decay

The lepton flavor violating $Z^{\prime}\to\tau\mu$ decay is studied in the context of several extended models that predict the existence of the new gauge boson named $Z^\prime$. A calculation of the strength of the lepton flavor violating $Z^\prime\mu\tau$ coupling is presented by using the most general renormalizable Lagrangian that includes lepton flavor violation. We used the experimental value of the muon magnetic dipole moment to bound this coupling, from which the $\mathrm{Re}(\Omega_{L\mu\tau}\Omega^\ast_{R\mu\tau})$ parameter is constrained and it is found that $\mathrm{Re}(\Omega_{L\mu\tau}\Omega^\ast_{R\mu\tau})\sim 10^{-2}$ for a $Z^\prime$ boson mass of 2 TeV. Alongside, we employed the experimental restrictions over the $\tau\to\mu\gamma$ and $\tau\to\mu\mu^+\mu^-$ processes in the context of several models that predict the existence of the $Z^\prime$ gauge boson to bound the mentioned coupling. The most restrictive bounds come from the calculation of the three-body decay. For this case, it was found that the most restrictive result is provided by a vector-like coupling, denoted as $|\Omega_{\mu\tau}|^2$, for the $Z_\chi$ case, finding around $10^{-2}$ for a $Z^\prime$ boson mass of 2 TeV. We used this information to estimate the branching ratio for the $Z^\prime\to\tau\mu$ decay. According to the analyzed models the least optimistic result is provided by the Sequential $Z$ model, which is of the order of $10^{-2}$ for a $Z^\prime$ boson mass around 2 TeV.Comment: Revised versio

Supersymmetric Flavor Models and the B --> phi K_S Anomaly

We consider the flavor structure of supersymmetric theories that can account for the deviation of the observed time-dependent CP asymmetry in B --> phi K_S from the standard model prediction. Assuming simple flavor symmetries and effective field theory, we investigate possible correlations between sizable supersymmetric contributions to b --> s transitions and to flavor changing processes that are more tightly constrained. With relatively few assumptions, we determine the properties of minimal Yukawa and soft mass textures that are compatible with the desired supersymmetric flavor-changing effect and constraints. We then present explicit models that are designed (at least approximately) to realize these textures. In particular, we present an Abelian model based on a single U(1) factor and a non-trivial extra-dimensional topography that can explain the CP asymmetry in B --> phi K_S, while suppressing other supersymmetric flavor changing effects through a high degree of squark-quark alignment.Comment: 18 pages LaTeX, 3 eps figure

Crack arrest through branching at curved weak interfaces: an experimental and numerical study

The phenomenon of arrest of an unstably-growing crack due to a curved weak interface is investigated. The weak interface can produce the deviation of the crack path, trapping the crack at the interface, leading to stable crack growth for certain interface geometries. This idea could be used as a technical solution for a new type of crack arrester, with a negligible impact on the global stiffness, strength and weight of the structure. In order to exploit this concept, an experimental campaign based on photo-elasticity and digital image correlation is carried out, showing the capability of curved weak interfaces to arrest cracks. The experiment is repeated for several geometrical configurations through the modification of the interface curvature radii. The phenomenon of crack deviation and subsequent arrest at the interface is also investigated with the assistance of a computational model based on the finite element method. The computational predictions provide the rationale for the interpretation of the experimental observations, and distinguish between the different behaviour of concave and convex interfaces. Consequently, as is shown in the present study, the curved interface concept fosters new routes for the attainment of structures with enhanced fracture resistance capacities, which are of paramount importance for materials and components used in extreme conditions.Comment: 19 pages, 13 figure

The prolate-to-oblate shape transition of phospholipid vesicles in response to frequency variation of an AC electric field can be explained by the dielectric anisotropy of a phospholipid bilayer

The external electric field deforms flaccid phospholipid vesicles into spheroidal bodies, with the rotational axis aligned with its direction. Deformation is frequency dependent: in the low frequency range (~ 1 kHz), the deformation is typically prolate, while increasing the frequency to the 10 kHz range changes the deformation to oblate. We attempt to explain this behaviour with a theoretical model, based on the minimization of the total free energy of the vesicle. The energy terms taken into account include the membrane bending energy and the energy of the electric field. The latter is calculated from the electric field via the Maxwell stress tensor, where the membrane is modelled as anisotropic lossy dielectric. Vesicle deformation in response to varying frequency is calculated numerically. Using a series expansion, we also derive a simplified expression for the deformation, which retains the frequency dependence of the exact expression and may provide a better substitute for the series expansion used by Winterhalter and Helfrich, which was found to be valid only in the limit of low frequencies. The model with the anisotropic membrane permittivity imposes two constraints on the values of material constants: tangential component of dielectric permittivity tensor of the phospholipid membrane must exceed its radial component by approximately a factor of 3; and the membrane conductivity has to be relatively high, approximately one tenth of the conductivity of the external aqueous medium.Comment: 17 pages, 6 figures; accepted for publication in J. Phys.: Condens. Matte

U(2)-like Flavor Symmetries and Approximate Bimaximal Neutrino Mixing

Models involving a U(2) flavor symmetry, or any of a number of its non-Abelian discrete subgroups, can explain the observed hierarchy of charged fermion masses and CKM angles. It is known that a large neutrino mixing angle connecting second and third generation fields may arise via the seesaw mechanism in these models, without a fine tuning of parameters. Here we show that it is possible to obtain approximate bimaximal mixing in a class of models with U(2)-like Yukawa textures. We find a minimal form for Dirac and Majorana neutrino mass matrices that leads to two large mixing angles, and show that our result can quantitatively explain atmospheric neutrino oscillations while accommodating the favored, large angle MSW solution to the solar neutrino problem. We demonstrate that these textures can arise in models by presenting a number of explicit examples.Comment: 20 pages RevTex4, 2 figure

Unusual T_c variation with hole concentration in Bi_2Sr_{2-x}La_xCuO_{6+\delta}

We have investigated the $T_c$ variation with the hole concentration $p$ in the La-doped Bi 2201 system, Bi$_2$Sr$_{2-x}$La$_x$CuO$_{6+\delta}$. It is found that the Bi 2201 system does not follow the systematics in $T_c$ and $p$ observed in other high-$T_c$ cuprate superconductors (HTSC's). The $T_c$ vs $p$ characteristics are quite similar to what observed in Zn-doped HTSC's. An exceptionally large residual resistivity component in the inplane resistivity indicates that strong potential scatterers of charge carriers reside in CuO$_2$ planes and are responsible for the unusual $T_c$ variation with $p$, as in the Zn-doped systems. However, contrary to the Zn-doped HTSC's, the strong scatter in the Bi 2201 system is possibly a vacancy in the Cu site.Comment: RevTeX, 3 figures, to be published in the Physical Review

Buspirone pharmacokinetics in autistic children

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/110082/1/cptclpt2005123.pd