Anomalous diffusion in a random nonlinear oscillator due to high frequencies of the noise

We study the long time behaviour of a nonlinear oscillator subject to a random multiplicative noise with a spectral density (or power-spectrum) that decays as a power law at high frequencies. When the dissipation is negligible, physical observables, such as the amplitude, the velocity and the energy of the oscillator grow as power-laws with time. We calculate the associated scaling exponents and we show that their values depend on the asymptotic behaviour of the external potential and on the high frequencies of the noise. Our results are generalized to include dissipative effects and additive noise.Comment: Expanded version of Proceedings StatPhys-Kolkata V

Marginal and Interaction Effects in Ordered Response Models

In discrete choice models the marginal effects of a variable that is interacted with another variable and the interaction term differ from the marginal effect of a variable that is not interacted with any variable. Standard software incorrectly estimates these marginal effects. I provide correct formulas for ordered response models that can be extended to other discrete choice models and an example using household survey data on food security in Bangladesh. Results show that marginal effects of the variables interacted and interaction term are estimated by standard software (such as STATA® 10) with large error and even with wrong sign

English language readability task performance in a mobile setting - the effect of gender

Mobile computing has become very common in the present day fast changing technological development. It is expected that in future, people will be more mobile than today and all kinds of tasks that are performed in the stationary environment will be undertaken in a mobile environment also. As traffic on the road and also the population are increasing at a very fast pace, the future generation will spend a lot of time in a mobile environment. Therefore, assessment of operators’ performance in a mobile setting will become all the more important. Mobile environment is influenced by vehicular vibration for all kinds of tasks. The present study made an attempt to explore the English language readability performance of a target group. Fourteen subjects (seven males and seven females) from an English language teaching institute were selected for this study. The base line value of reading speed was obtained on the basis of stationary environment reading task performance. Reading speed was noted in the number of words read per minute (NWRPM). The same subjects were used for reading in the vibratory environment and difference in the performance was noticed. A stimulus was presented on a lap-top in both cases. Vibration was assessed on the basis of ISO 2631-1 (1997) guideline. ANOVA statistical tool was used to analyze the data. The result indicated that the performance of operators was significantly affected due to the presence of vibration and text/background color

On the Real Spectra of Calogero Model with Complex Coupling

We study the eigenvalue problem of the rational Calogero model with the coupling of the inverse-square interaction as a complex number. We show that although this model is manifestly non-invariant under the combined parity and time-reversal symmetry ${\cal{PT}}$, the eigenstates corresponding to the zero value of the generalized angular momentum have real energies.Comment: revtex4 8 pages, 2 figure

Realisations of GLp,q(2)GL_{p,q}(2) quantum group and its coloured extension through a novel Hopf algebra with five generators

A novel Hopf algebra $( {\tilde G}_{r,s} )$, depending on two deformation parameters and five generators, has been constructed. This ${\tilde G}_{r,s}$ Hopf algebra might be considered as some quantisation of classical $GL(2) \otimes GL(1)$ group, which contains the standard $GL_q(2)$ quantum group (with $q=r^{-1}$) as a Hopf subalgebra. However, we interestingly observe that the two parameter deformed $GL_{p,q}(2)$ quantum group can also be realised through the generators of this ${\tilde G}_{r,s}$ algebra, provided the sets of deformation parameters $p,~q$ and $r,~s$ are related to each other in a particular fashion. Subsequently we construct the invariant noncommutative planes associated with ${\tilde G}_{r,s}$ algebra and show how the two well known Manin planes corresponding to $GL_{p,q}(2)$ quantum group can easily be reproduced through such construction. Finally we consider the `coloured' extension of $GL_{p,q}(2)$ quantum group as well as corresponding Manin planes and explore their intimate connection with the `coloured' extension of ${\tilde G}_{r,s}$ Hopf structure.Comment: 24 page