218 research outputs found

    Formulation of an Electrostatic Field with a Charge Density in the Presence of a Minimal Length Based on the Kempf Algebra

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    In a series of papers, Kempf and co-workers (J. Phys. A: Math. Gen. {\bf 30}, 2093, (1997); Phys. Rev. D {\bf52}, 1108, (1995); Phys. Rev. D {\bf55}, 7909, (1997)) introduced a D-dimensional (β,β)(\beta,\beta')-two-parameter deformed Heisenberg algebra which leads to a nonzero minimal observable length. In this work, the Lagrangian formulation of an electrostatic field in three spatial dimensions described by Kempf algebra is studied in the case where β=2β\beta'=2\beta up to first order over deformation parameter β\beta. It is shown that there is a similarity between electrostatics in the presence of a minimal length (modified electrostatics) and higher derivative Podolsky's electrostatics. The important property of this modified electrostatics is that the classical self-energy of a point charge becomes a finite value. Two different upper bounds on the isotropic minimal length of this modified electrostatics are estimated. The first upper bound will be found by treating the modified electrostatics as a classical electromagnetic system, while the second one will be estimated by considering the modified electrostatics as a quantum field theoretic model. It should be noted that the quantum upper bound on the isotropic minimal length in this paper is near to the electroweak length scale (electroweak1018m)(\ell_{electroweak}\sim 10^{-18}\, m).Comment: 11 pages, no figur

    Optimizing an Adaptive Neuro-Fuzzy Inference System for Spatial Prediction of Landslide Susceptibility Using Four State-of-the-art Metaheuristic Techniques.

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    Four state-of-the-art metaheuristic algorithms including the genetic algorithm (GA), particle swarm optimization (PSO), differential evolutionary (DE), and ant colony optimization (ACO) are applied to an adaptive neuro-fuzzy inference system (ANFIS) for spatial prediction of landslide susceptibility in Qazvin Province (Iran). To this end, the landslide inventory map, composed of 199 identified landslides, is divided into training and testing landslides with a 70:30 ratio. To create the spatial database, thirteen landslide conditioning factors are considered within the geographic information system (GIS). Notably, the spatial interaction between the landslides and mentioned conditioning factors is analyzed by means of frequency ratio (FR) theory. After the optimization process, it was shown that the DE-based model reaches the best response more quickly than other ensembles. The landslide susceptibility maps were developed, and the accuracy of the models was evaluated by a ranking system, based on the calculated area under the receiving operating characteristic curve (AUROC), mean absolute error, and mean square error (MSE) accuracy indices. According to the results, the GA-ANFIS with a total ranking score (TRS) = 24 presented the most accurate prediction, followed by PSO-ANFIS (TRS = 17), DE-ANFIS (TRS = 13), and ACO-ANFIS (TRS = 6). Due to the excellent results of this research, the developed landslide susceptibility maps can be applied for future planning and decision making of the related area

    Formulation of the Spinor Field in the Presence of a Minimal Length Based on the Quesne-Tkachuk Algebra

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    In 2006 Quesne and Tkachuk (J. Phys. A: Math. Gen. {\bf 39}, 10909, 2006) introduced a (D+1)-dimensional (β,β)(\beta,\beta')-two-parameter Lorentz-covariant deformed algebra which leads to a nonzero minimal length. In this work, the Lagrangian formulation of the spinor field in a (3+1)-dimensional space-time described by Quesne-Tkachuk Lorentz-covariant deformed algebra is studied in the case where β=2β\beta'=2\beta up to first order over deformation parameter β\beta. It is shown that the modified Dirac equation which contains higher order derivative of the wave function describes two massive particles with different masses. We show that physically acceptable mass states can only exist for β<18m2c2\beta<\frac{1}{8m^{2}c^{2}}. Applying the condition β<18m2c2\beta<\frac{1}{8m^{2}c^{2}} to an electron, the upper bound for the isotropic minimal length becomes about 3×1013m3 \times 10^{-13}m. This value is near to the reduced Compton wavelength of the electron (λc=mec=3.86×1013m)(\lambda_c = \frac{\hbar}{m_{e}c} = 3.86\times 10^{-13} m) and is not incompatible with the results obtained for the minimal length in previous investigations.Comment: 11 pages, no figur

    Effects of Using Pozzolan and Portland Cement in the Treatment of Dispersive Clay

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    Use of dispersive clay as construction material requires treatment such as by chemical addition. Treatments to dispersive clay using pozzolan and Portland cement, singly and simultaneously, were carried out in this study. When used alone, the optimum amount of pozzolan required to treat a fully dispersive clay sample was 5%, but the curing time to reduce dispersion potential, from 100% to 30% or less, was 3 month long. On the other hand, also when used alone, a 3% cement content was capable of reducing dispersion potential to almost zero percent in only 7 days; and a 2% cement content was capable of achieving similar result in 14 days. However, treatment by cement alone is costly and could jeopardize the long term performance. Thus, a combined 5% pozzolan and 1.5% cement content was found capable of reducing dispersion potential from 100% to zero percent in 14 days. The results indicate that although simultaneous treatment with pozzolan and cement would extend the required curing time in comparison to treatment by cement alone of a higher content, the task could still be carried out in a reasonable period of curing time while avoiding the drawbacks of using either pozzolan or cement alone

    Preparation of immunotoxin herceptin-botulinum and killing effects on two breast cancer cell lines

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    Background: Worldwide, breast cancer is the most common cancer diagnosed among women and a leading cause of cancer deaths. The age of onset in Iran has become reduced by a decade for unknown reasons. Herceptin, a humanized monoclonal antibody, is a target therapy for breast cancer cells with over expression of HER2-neu receptors, but it is an expensive drug with only 20 beneficial rate of survival. This study introduces a novel approach to enhance the efficacy of this drug through immunoconjugation of the antibody to botulinum toxin. Decreasing the cost and adverse effects of the antibody were secondary goals of this study. Materials and Methods: Botulinum toxin was conjugated with Herceptin using heterobifunctional cross linkers, succinimidyl acetylthiopropionate (SATP) and sulfo-succinimidyl-4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) according to the supplier's guidelines and tested on two breast cancer cell lines: SK-BR-3 and BT-474. Toxin and Herceptin were also used separately as controls. The cytotoxicity assay was also performed using the new bioconjugate on cultured cells with Alamar blue and a fluorescence plate reader. Results: Herceptin-Toxin bioconjugation significantly improved Herceptin efficacy on both breast cancer cell lines when compared to the control group. Conclusions: Toxin-Herceptin bioconjugation can be a potential candidate with increased efficiency for treating breast cancer patients with over expression of the HER2 receptor

    Quantum Gravitational Corrections to the Real Klein-Gordon Field in the Presence of a Minimal Length

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    The (D+1)-dimensional (β,β)(\beta,\beta')-two-parameter Lorentz-covariant deformed algebra introduced by Quesne and Tkachuk [C. Quesne and V. M. Tkachuk, J. Phys. A: Math. Gen. \textbf {39}, 10909 (2006).], leads to a nonzero minimal uncertainty in position (minimal length). The Klein-Gordon equation in a (3+1)-dimensional space-time described by Quesne-Tkachuk Lorentz-covariant deformed algebra is studied in the case where β=2β\beta'=2\beta up to first order over deformation parameter β\beta. It is shown that the modified Klein-Gordon equation which contains fourth-order derivative of the wave function describes two massive particles with different masses. We have shown that physically acceptable mass states can only exist for β<18m2c2\beta<\frac{1}{8m^{2}c^{2}} which leads to an isotropic minimal length in the interval 1017m<(Xi)0<1015m10^{-17}m<(\bigtriangleup X^{i})_{0}<10^{-15}m. Finally, we have shown that the above estimation of minimal length is in good agreement with the results obtained in previous investigations.Comment: 10 pages, no figur

    A non-uniform predictor-observer for a networked control system

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    The final publication is available at Springer via http://dx.doi.org/10.1007/s12555-011-0621-5This paper presents a Non-Uniform Predictor-Observer (NUPO) based control approach in order to deal with two of the main problems related to Networked Control Systems (NCS) or Sensor Networks (SN): time-varying delays and packet loss. In addition, if these delays are longer than the sampling period, the packet disordering phenomenon can appear. Due to these issues, a (scarce) nonuniform, delayed measurement signal could be received by the controller. But including the NUPO proposal in the control system, the delay will be compensated by the prediction stage, and the nonavailable data will be reconstructed by the observer stage. So, a delay-free, uniformly sampled controller design can be adopted. To ensure stability, the predictor must satisfy a feasibility problem based on a time-varying delay-dependent condition expressed in terms of Linear Matrix Inequalities (LMI). 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    Interacting Dark Energy in Ho\v{r}ava-Lifshitz Cosmology

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    In the usual Ho\v{r}ava-Lifshitz cosmological models, the scalar field is responsible for dark matter. Using an additional scalar field, Saridakis \cite{sari} has formulated Ho\v{r}ava-Lifshitz cosmology with an effective dark energy sector. In the paper \cite{sari} the scalar fields do not interact with each other, here we extend this work to the interacting case, where matter scalar field ϕ\phi interact with dark energy scalar field σ\sigma. We will show that in contrast with \cite{sari}, where σ\sigma-filed is absent, we can obtain wdeff<1w_d ^{\rm eff}<-1, that is we result to an effective dark energy presenting phantom behaviour. This behaviour is pure effect of the interaction.Comment: 10 pages, no figur
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