Optimal cutting directions and rectangle orientation algorithm

The first stage in hierarchical approaches to Floorplan Design defines topological relations between components that intend to optimize a given objective in a circuit board. These relations determine a placement that is subsequently optimized in order to minimize a cost measurement (that will probably be one between chip area or perimeter). The board optimization gives rise to multiple subproblems that need to be answered in order to obtain a good solution. Among the most relevant ones we find the problem of defining the optimal orientation of cells and the definition of the optimal cutting sequence that minimize the placement board area. We will present a generalization of an algorithm due to Stockmeyer so that it obtains a solution that not only defines the optimal cell orientation but also the slicing cuts sequence that will lead to this optimal orientation and overall area minimization.http://www.sciencedirect.com/science/article/B6VCT-3TN9R05-B/1/3ed2fa5acf5e53dff08af5423738ac8

Integrable variant of the one-dimensional Hubbard model

A new integrable model which is a variant of the one-dimensional Hubbard model is proposed. The integrability of the model is verified by presenting the associated quantum R-matrix which satisfies the Yang-Baxter equation. We argue that the new model possesses the SO(4) algebra symmetry, which contains a representation of the $\eta$-pairing SU(2) algebra and a spin SU(2) algebra. Additionally, the algebraic Bethe ansatz is studied by means of the quantum inverse scattering method. The spectrum of the Hamiltonian, eigenvectors, as well as the Bethe ansatz equations, are discussed

A variational approach for the Quantum Inverse Scattering Method

We introduce a variational approach for the Quantum Inverse Scattering Method to exactly solve a class of Hamiltonians via Bethe ansatz methods. We undertake this in a manner which does not rely on any prior knowledge of integrability through the existence of a set of conserved operators. The procedure is conducted in the framework of Hamiltonians describing the crossover between the low-temperature phenomena of superconductivity, in the Bardeen-Cooper-Schrieffer (BCS) theory, and Bose-Einstein condensation (BEC). The Hamiltonians considered describe systems with interacting Cooper pairs and a bosonic degree of freedom. We obtain general exact solvability requirements which include seven subcases which have previously appeared in the literature.Comment: 18 pages, no eps figure

Protein aggregation containing beta-amyloid, alpha-synuclein and hyperphosphorylated tau in cultured cells of hippocampus, substantia nigra and locus coeruleus after rotenone exposure

<p>Abstract</p> <p>Background</p> <p>Protein aggregates containing alpha-synuclein, beta-amyloid and hyperphosphorylated tau are commonly found during neurodegenerative processes which is often accompanied by the impairment of mitochondrial complex I respiratory chain and dysfunction of cellular systems of protein degradation. In view of this, we aimed to develop an <it>in vitro </it>model to study protein aggregation associated to neurodegenerative diseases using cultured cells from hippocampus, locus coeruleus and substantia nigra of newborn Lewis rats exposed to 0.5, 1, 10 and 25 nM of rotenone, which is an agricultural pesticide, for 48 hours.</p> <p>Results</p> <p>We demonstrated that the proportion of cells in culture is approximately the same as found in the brain nuclei they were extracted from. Rotenone at 0.5 nM was able to induce alpha-synuclein and beta amyloid aggregation, as well as increased hyperphosphorylation of tau, although high concentrations of this pesticide (over 1 nM) lead cells to death before protein aggregation. We also demonstrated that the 14kDa isoform of alpha-synuclein is not present in newborn Lewis rats.</p> <p>Conclusion</p> <p>Rotenone exposure may lead to constitutive protein aggregation <it>in vitro</it>, which may be of relevance to study the mechanisms involved in idiopathic neurodegeneration.</p

Coffee acclimation to high temperatures involves lipid composition changes of chloroplast membranes and is strenghtened by elevated air CO2 concentration.

Depending on the greenhouse gas emission scenarios, air [CO2] could rise to between 421 and 936 ?L L-1, accompanied by a global surface warming between 0.3 and 4.8?C along the 2nd half of the present century. It is well known that supra-optimal air temperatures may cause significant disturbances in metabolism and plant growth, since biochemical reactions are accelerated, the chemical bonds are weakened and the lipid matrix of membranes becomes more fluid. Thylakoid membranes are particularly sensitive to supra-optimal temperatures, so that impairments at the photochemical steps of photosynthesis are among the first indicators of sensitivity to heat stress. Plants acclimate to thermal stress by means of a myriad of mechanisms, such as, increased expression and activity of heat shock proteins, reinforcement of antioxidant defense system, and changes in membrane composition regarding lipid classes and fatty acid (FA), as well as their degree of unsaturation. Therefore, the objective of this study was to evaluate whether the increase in [CO2] is involved in the triggering of lipid remodeling of chloroplasts membranes under high temperature conditions, which could contribute to maintain an adequate functional fluidity. Plants were grown for 1 year under controlled conditions (temperature, RH, irradiance, photoperiod), at 380 or 700 µL CO2 L-1 air, without nutrient, water and root space limitations, and then subjected to temperature increase (0.5 ºC/day) from 25/20 ºC (day/night) to 42/34ºC. Lipid classes were separated by thin layer chromatography on G60 silicagel plates and fatty acid methyl esters were analyzed by gas?liquid chromatography. The results suggested that regardless of [CO2], increases in temperature resulted in changes in lipid membranes composition, which could contribute to maintaining the functionality of thylakoid membranes. However, the mitigating effect of increased [CO2] on coffee photosynthetic apparatus at high temperatures observed earlier may be linked to stronger increases in saturation degree and/or with the increasing the weight of galactolipids classes at 37/30 °C (as compared to 380 µL CO2 L-1 plants)

Topological defects and open inflation

Topological defects can naturally be formed soon after bubble nucleation in the open inflation scenario. The defects are not completely diluted away by the subsequent period of inflation in the bubble interior and can produce observable large-scale microwave background anisotropies. Superheavy strings and monopoles attached to the strings can act as gravitational lenses with angular separation between the images of up to an arc minute.Comment: 11 pages, revte

Project Proof: Internet Enabled Process Reengineering at J.D. Edwards & Company

J.D. Edwards is a provider of the new generation of ERP and collaborative commerce solutions. This case study describes the challenges faced internally by the company to upgrade to the latest enterprise software it would sell to the world. Dubbed Project PROOF, the project started in June 2001 and was completed in November 2002. The perspectives of the CIO, the program manager, and other key personnel are presented. The case study highlights the issues that arise in an enterprise software implementation project. In addition, the case touches upon issues of project management, process redesign, and marketing. The case study uses a multimedia format to add richness and detail. Although J.D. Edwards was acquired in 2003, the issues discussed are relevant to current business practices

Avaliação de dietas contendo farelo de mandioca e palma forrageira por meio do teor de uréia no soro de ovinos.

Neste trabalho foi avaliada a substituição do farelo de mandioca pelo farelo de palma forrageira através do teor de uréia no soro. Foram utilizados 20 ovinos, machos, não castrados, mestiços da raça Santa Inês, com idade média de nove meses e com peso médio de 20,0 +-: 4,0 kg. Utilizaram-se os ingredientes feno de capim buffel amoniado com uréia a 4%, farelo de palma e farelo de mandioca. Os níveis de substituição da raspa de mandioca pelo farelo de palma foram de 0, 25, 50, 75 e 100%, representando os tratamentos. O delineamento experimental foi o de blocos ao acaso com quatro repetições e cinco tratamentos. Procederam-se quatro coletas de sangue. O teor de uréia no soro apresentou comportamento linear em relação ao CMS e o CPB. O teor de uréia no soro mostrou-se um eficiente monitor das dietas propostas, porém deve ser utilizado em conjunto com outras formas de avaliação com o intuito de se alcançar um eficiente manejo alimentar de ruminantes