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

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

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

Benchmarking the Security Protocol and Data Model (SPDM) for component authentication

Efforts to secure computing systems via software traditionally focus on the operating system and application levels. In contrast, the Security Protocol and Data Model (SPDM) tackles firmware level security challenges, which are much harder (if at all possible) to detect with regular protection software. SPDM includes key features like enabling peripheral authentication, authenticated hardware measurements retrieval, and secure session establishment. Since SPDM is a relatively recent proposal, there is a lack of studies evaluating its performance impact on real-world applications. In this article, we address this gap by: (1) implementing the protocol on a simple virtual device, and then investigating the overhead introduced by each SDPM message; and (2) creating an SPDM-capable virtual hard drive based on VirtIO, and comparing the resulting read/write performance with a regular, unsecured implementation. Our results suggest that SPDM bootstrap time takes the order of tens of milliseconds, while the toll of introducing SPDM on hard drive communication highly depends on specific workload patterns. For example, for mixed random read/write operations, the slowdown is negligible in comparison to the baseline unsecured setup. Conversely, for sequential read or write operations, the data encryption process becomes the bottleneck, reducing the performance indicators by several orders of magnitude.Comment: 10 pages, 8 figure