Analysis of side writing asymmetry

The side writing asymmetry of a recording head was investigated using an overwrite configuration that enhances the edge effects. The track profiles of the overwrite patterns were measured for analyzing the side writing performance of the head. Magnetic force microscope (MFM) images of the overwrite patterns were studied using fast Fourier transforms (FFT), and they confirmed the profiling results. We measured weak edge effects at good pole alignment. The experiments were performed with metal evaporated (ME) and metal particle (MP) tapes having magnetic layers between 50 and 300 nm

Thermodynamics of the 3-State Potts Spin Chain

We demonstrate the relation of the infrared anomaly of conformal field theory with entropy considerations of finite temperature thermodynamics for the 3-state Potts chain. We compute the free energy and compute the low temperature specific heat for both the ferromagnetic and anti-ferromagnetic spin chains, and find the central charges for both.Comment: 18 pages, LaTex. Preprint # ITP-SB-92-60. References added and first section expande

Analyticity and Integrabiity in the Chiral Potts Model

We study the perturbation theory for the general non-integrable chiral Potts model depending on two chiral angles and a strength parameter and show how the analyticity of the ground state energy and correlation functions dramatically increases when the angles and the strength parameter satisfy the integrability condition. We further specialize to the superintegrable case and verify that a sum rule is obeyed.Comment: 31 pages in harvmac including 9 tables, several misprints eliminate

XXZXXZ model as effective Hamiltonian for generalized Hubbard models with broken η\eta-symmetry

We consider the limit of strong Coulomb attraction for generalized Hubbard models with $\eta$-symmetry. In this limit these models are equivalent to the ferromagnetic spin-1/2 Heisenberg quantum spin chain. In order to study the behaviour of the superconducting phase in the electronic model under perturbations which break the $\eta$-symmetry we investigate the ground state of the ferromagnetic non-critical $XXZ$-chain in the sector with fixed magnetization. It turns out to be a large bound state of $N$ magnons. We find that the perturbations considered here lead to the disappearance of the off-diagonal longe-range order.Comment: Results of previous version are generalized, new title, references added. 10 pages, Latex, no figure

PLANT TOLERANCE TO DROUGHT: MODULATION OF STOMATAL MOVEMENTS

Plants are continuously exposed to several types of abiotic and biotic stresses. As sessile organisms, the mechanisms developed by plants to respond to those stresses are extremely vital for the plant growth and survival. Drought is one of the most common environmental stresses to which plants are exposed and the major cause of losses in crop production throughout the world. One of the primary plant response against water loss and dehydration is reducing the transpiration from the leaves by the closure of stomatal pores, guard cells in fact sense and respond to the environmental changes by the activation of complex intracellular signalling cascades followed by a variation of their turgor pressure and volume. Thus, understanding the complex mechanisms that control the opening and closure of stomata represents an attractive goal. In this PhD thesis the results obtained by the analysis of two Arabidopsis genes involved in stomatal movements, AtMYB60 and \u3b3VPE, are presented. The approach performed to characterise putative targets of AtMYB60, a transcription factor specifically expressed in guard cells, was described. Then, the AtMYB60 promoter was characterised through serial deletion and mutagenesis analysis and some DOF-binding sites were identified as fundamental cis-elements for the specific activity of this promoter in guard cells. Finally, the improved tolerance to water stress of \u3b3vpe plant was reported and the phenotypic alteration of the mutant in stomatal aperture was described

Novel Profiling Model and Side Effects of Helical Scan Silicon Heads

Partial erasure of track edges was directly measured from triple-track patterns using a novel model to interpret the output profiles. The model is based on representing the read head as the sum of a reference width, wavelength independent, and two side reading effective widths that are wavelength dependent. We applied this technique to measure erase bands and side read widths of an advanced helical scan silicon head with 3.5-/spl mu/m pole width, in combination with metal particle tape with coercivity H/sub c/ = 135 kA/m. The good pole alignment of the head minimizes side effects and we report an erase band of 0.3 /spl mu/m for a 0.5-/spl mu/m wavelength track overwriting the edge of a track having the same wavelength