Transfer matrix solution of the Wako-Sait\^o-Mu\~noz-Eaton model augmented by arbitrary short range interactions

The Wako-Sait{\^o}-Mu\~noz-Eaton (WSME) model, initially introduced in the theory of protein folding, has also been used in modeling the RNA folding and some epitaxial phenomena. The advantage of this model is that it admits exact solution in the general inhomogeneous case (Bruscolini and Pelizzola, 2002) which facilitates the study of realistic systems. However, a shortcoming of the model is that it accounts only for interactions within continuous stretches of native bonds or atomic chains while neglecting interstretch (interchain) interactions. But due to the biopolymer (atomic chain) flexibility, the monomers (atoms) separated by several non-native bonds along the sequence can become closely spaced. This produces their strong interaction. The inclusion of non-WSME interactions into the model makes the model more realistic and improves its performance. In this study we add arbitrary interactions of finite range and solve the new model by means of the transfer matrix technique. We can therefore exactly account for the interactions which in proteomics are classified as medium- and moderately long-range ones.Comment: 15 pages, 2 figure

Absence of the Transition into Abrikosov Vortex State of Two-Dimensional Type-II Superconductor with Weak Pinning

The resistive properties of thin amorphous NbO_{x} films with weak pinning were investigated experimentally above and below the second critical field H_{c2}. As opposed to bulk type II superconductors with weak pinning where a sharp change of resistive properties at the transition into the Abrikosov state is observed at H_{c4}, some percent below H_{c2} (V.A.Marchenko and A.V.Nikulov, 1981), no qualitative change of resistive properties is observed down to a very low magnetic field, H_{c4} < 0.006 H_{c2}, in thin films with weak pinning. The smooth dependencies of the resistivity observed in these films can be described by paraconductivity theory both above and below H_{c2}. This means that the fluctuation superconducting state without phase coherence remains appreciably below H_{c2} in the two-dimensional superconductor with weak pinning. The difference the H_{c4}/H_{c2} values, i.e. position of the transition into the Abrikosov state, in three- and two-dimensional superconductors conforms to the Maki-Takayama result 1971 year according to which the Abrikosov solution 1957 year is valid only for a superconductor with finite dimensions. Because of the fluctuation this solution obtained in the mean field approximation is not valid in a relatively narrow region below H_{c2} for bulk superconductors with real dimensions and much below H_{c2} for thin films with real dimensions. The superconducting state without phase coherence should not be identified with the mythical vortex liquid because the vortex, as a singularity in superconducting state with phase coherence, can not exist without phase coherence.Comment: 4 pages, 4 figure

Title Stabilization of Membrane Pores by Packing

We present a model for pore stabilization in membranes without surface tension. Whereas an isolated pore is always unstable (since it either shrinks tending to re-seal or grows without bound til to membrane disintegration), it is shown that excluded volume interactions in a system of many pores can stabilize individual pores of a given size in a certain range of model parameters. For such a multipore membrane system, the distribution of pore size and associated pore lifetime are calculated within the mean field approximation. We predict that, above certain temperature when the effective line tension becomes negative, the membrane exhibits a dynamic sieve-like porous structure.Comment: 4 pages, 4 figure

Electric-field induced capillary interaction of charged particles at a polar interface

We study the electric-field induced capillary interaction of charged particles at a polar interface. The algebraic tails of the electrostatic pressure of each charge results in a deformation of the interface $u\sim \rho ^{-4}$. The resulting capillary interaction is repulsive and varies as $\rho ^{-6}$ with the particle distance. As a consequence, electric-field induced capillary forces cannot be at the origin of the secondary minimum observed recently for charged PMMA particles at on oil-water interface.Comment: June 200

Metastability of life

The physical idea of the natural origin of diseases and deaths has been presented. The fundamental microscopical reason is the destruction of any metastable state by thermal activation of a nucleus of a nonreversable change. On the basis of this idea the quantitative theory of age dependence of death probability has been constructed. The obtained simple Death Laws are very accurately fulfilled almost for all known diseases.Comment: 3 pages, 4 figure

Wind ionization structure of the short-period eclipsing LMC Wolf-Rayet binary BAT99-129: preliminary results

BAT99-129 is a rare, short-period eclipsing Wolf-Rayet binary in the Large Magellanic Cloud. We present here medium-resolution NTT/EMMI spectra that allow us to disentangle the spectra of the two components and find the orbital parameters of the binary. We also present VLT/FORS1 spectra of this binary taken during the secondary eclipse, i.e. when the companion star passes in front of the Wolf-Rayet star. With these data we are able to extract, for the first time in absolute units for a WR+O binary, the sizes of the line emitting regions.Comment: 6 pages, 5 figures, to appear in proc. of "Close Binaries in the 21st Century: New Opportunities and Challenges", 2005 - Corrected Figure

Explicit solutions to the Korteweg-de Vries equation on the half line

Certain explicit solutions to the Korteweg-de Vries equation in the first quadrant of the $xt$-plane are presented. Such solutions involve algebraic combinations of truly elementary functions, and their initial values correspond to rational reflection coefficients in the associated Schr\"odinger equation. In the reflectionless case such solutions reduce to pure $N$-soliton solutions. An illustrative example is provided.Comment: 17 pages, no figure

Low-energy expansion formula for one-dimensional Fokker-Planck and Schr\"odinger equations with periodic potentials

We study the low-energy behavior of the Green function for one-dimensional Fokker-Planck and Schr\"odinger equations with periodic potentials. We derive a formula for the power series expansion of reflection coefficients in terms of the wave number, and apply it to the low-energy expansion of the Green function

The Response to a Perturbation in the Reflection Amplitude

We apply inverse scattering theory to calculate the functional derivative of the potential $V(x)$ and wave function $\psi(x,k)$ of a one-dimensional Schr\"odinger operator with respect to the reflection amplitude $r(k)$.Comment: 16 pages, no figure