5,249 research outputs found

    Formal Verification of Safety Properties for Ownership Authentication Transfer Protocol

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    In ubiquitous computing devices, users tend to store some valuable information in their device. Even though the device can be borrowed by the other user temporarily, it is not safe for any user to borrow or lend the device as it may cause private data of the user to be public. To safeguard the user data and also to preserve user privacy we propose and model the technique of ownership authentication transfer. The user who is willing to sell the device has to transfer the ownership of the device under sale. Once the device is sold and the ownership has been transferred, the old owner will not be able to use that device at any cost. Either of the users will not be able to use the device if the process of ownership has not been carried out properly. This also takes care of the scenario when the device has been stolen or lost, avoiding the impersonation attack. The aim of this paper is to model basic process of proposed ownership authentication transfer protocol and check its safety properties by representing it using CSP and model checking approach. For model checking we have used a symbolic model checker tool called NuSMV. The safety properties of ownership transfer protocol has been modeled in terms of CTL specification and it is observed that the system satisfies all the protocol constraint and is safe to be deployed.Comment: 16 pages, 7 figures,Submitted to ADCOM 201

    Systemic Therapy in Endometrial Cancer: Recent Advances.

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    Endometrial cancer is a chemosensitive disease. Studies have established a clear benefit of chemotherapy in advanced stages and trials are ongoing to define its role in early stages as well. As more molecular pathways are being elucidated there is increasing role for targeted agents and future looks quite promising. We did an extensive search both online and offline for all the relevant articles including chemotherapy and targeted therapy for endometrial cancer

    Humic acids in sediments of North-Central Arabian Sea, west coast of India

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    Sediment samples (28) collected during the ORV Sagar Kanya cruise-29, were analysed for humic acid (HA) concentration from the North-Central Arabian Sea. Generally oceanic samples had more HA concentration than the continental shelf (< 200 m depth) samples. The photo-acoustic infrared spectra of shelf sediment HA indicated the presence of more C-H saturated aliphatic chains, while oceanic HA had few peaks for the above groups. Both the IR spectra indicated the absence of aromatic C = C, carbonyl, ketonic groups. Clayey-silt sediment generally had higher concentration of HA compared to sandy-silt type of sediment

    Global Modeling of Spur Formation in Spiral Galaxies

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    We investigate the formation of substructure in spiral galaxies using global MHD simulations, including gas self-gravity. Our models extend previous local models by Kim and Ostriker (2002) by including the full effects of curvilinear coordinates, a realistic log-spiral perturbation, self-gravitational contribution from 5 radial wavelengths of the spiral shock, and variation of density and epicyclic frequency with radius. We show that with realistic Toomre Q values, self-gravity and galactic differential rotation produce filamentary gaseous structures with kpc-scale separations, regardless of the strength -- or even presence -- of a stellar spiral potential. However, the growth of sheared features distinctly associated with the spiral arms, described as spurs or feathers in optical and IR observations of many spiral galaxies, requires a sufficiently strong spiral potential in self gravitating models. Unlike independently-growing ''background'' filaments, the orientation of arm spurs depends on galactic location. Inside corotation, spurs emanate outward, on the convex side of the arm; outside corotation, spurs grow inward, on the concave side of the arm. Based on spacing, orientation, and the relation to arm clumps, it is possible to distinguish ''true spurs'' that originate as instabilities in the spiral arms from independently growing ''background'' filaments. Our models also suggest that magnetic fields are important in preserving grand design spiral structure when gas in the arms fragments via self-gravity into GMCs.Comment: 36 pages, 17 figures, Accepted for publication in ApJ. PDF version with high resolution figures available at http://www.astro.umd.edu/~shetty/Research

    Symmetry energy and the isospin dependent equation of state

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    The isoscaling parameter α\alpha, from the fragments produced in the multifragmentation of 58^{58}Ni + 58^{58}Ni, 58^{58}Fe + 58^{58}Ni and 58^{58}Fe + 58^{58}Fe reactions at 30, 40 and 47 MeV/nucleon, was compared with that predicted by the antisymmetrized molecular dynamic (AMD) calculation based on two different nucleon-nucleon effective forces, namely the Gogny and Gogny-AS interaction. The results show that the data agrees better with the choice of Gogny-AS effective interaction, resulting in a symmetry energy of \sim 18-20 MeV. The observed value indicate that the fragments are formed at a reduced density of \sim 0.08 fm3^{-3}.Comment: 5 pages, 5 figures, Accepted for publication in Phys. Rev. C (Rapid Communication

    Silicon-induced changes in antifungal phenolic acids, flavonoids, and key phenylpropanoid pathway genes during the interaction between miniature roses and the biotrophic pathogen <em>Podosphaera pannosa</em>

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    Application of 3.6 mm silicon (Si+) to the rose (Rosa hybrida) cultivar Smart increased the concentration of antimicrobial phenolic acids and flavonoids in response to infection by rose powdery mildew (Podosphaera pannosa). Simultaneously, the expression of genes coding for key enzymes in the phenylpropanoid pathway (phenylalanine ammonia lyase, cinnamyl alcohol dehydrogenase, and chalcone synthase) was up-regulated. The increase in phenolic compounds correlated with a 46% reduction in disease severity compared with inoculated leaves without Si application (Si−). Furthermore, Si application without pathogen inoculation induced gene expression and primed the accumulation of several phenolics compared with the uninoculated Si− control. Chlorogenic acid was the phenolic acid detected in the highest concentration, with an increase of more than 80% in Si+ inoculated compared with Si− uninoculated plants. Among the quantified flavonoids, rutin and quercitrin were detected in the highest concentrations, and the rutin concentration increased more than 20-fold in Si+ inoculated compared with Si− uninoculated plants. Both rutin and chlorogenic acid had antimicrobial effects on P. pannosa, evidenced by reduced conidial germination and appressorium formation of the pathogen, both after spray application and infiltration into leaves. The application of rutin and chlorogenic acid reduced powdery mildew severity by 40% to 50%, and observation of an effect after leaf infiltration indicated that these two phenolics can be transported to the epidermal surface. In conclusion, we provide evidence that Si plays an active role in disease reduction in rose by inducing the production of antifungal phenolic metabolites as a response to powdery mildew infection

    Kinematics of Spiral Arm Streaming in M51

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    We use CO and H alpha velocity fields to study the gas kinematics in the spiral arms and interarms of M51 (NGC 5194), and fit the 2D velocity field to estimate the radial and tangential velocity components as a function of spiral phase (arm distance). We find large radial and tangential streaming velocities, which are qualitatively consistent with the predictions of density wave theory and support the existence of shocks. The streaming motions are complex, varying significantly across the galaxy as well as along and between arms. Aberrations in the velocity field indicate that the disk is not coplanar, perhaps as far in as 20\arcsec\ (800 pc) from the center. Velocity profile fits from CO and H alpha are typically similar, suggesting that most of the H alpha emission originates from regions of recent star formation. We also explore vortensity and mass conservation conditions. Vortensity conservation, which does not require a steady state, is empirically verified. The velocity and density profiles show large and varying mass fluxes, which are inconsistent with a steady flow for a single dominant global spiral mode. We thus conclude that the spiral arms cannot be in a quasi-steady state in any rotating frame, and/or that out of plane motions may be significant.Comment: 50 pages, including 20 figures; Accepted for publication in ApJ. PDF version with high resolution figures available at http://www.astro.umd.edu/~shetty/Research
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