Excitations and S-matrix for su(3) spin chain combining 3{3} and ${3^{*}}

The associated Hamiltonian for a su(3) spin chain combining ${3}$ and ${3^{*}}$ representations is calculated. The ansatz equations for this chain are obtained and solved in the thermodynamic limit, and the ground state and excitations are described. Thus, relations between the number of roots and the number of holes in each level have been found . The excited states are characterized by means of these quantum numbers. Finally, the exact S matrix for a state with two holes is found.Comment: 17 pages, plaintex, harvmac (to be published in J. of Phys. A

Green Hospitals, Green Healthcare

Concepts related to ‘green health’ and ‘green hospitals’ are rapidly changing and varying their scopes towards wider perspectives. Environmental health considers the natural, built and social environments, implying a better understanding of the way they impact on health, and accepting that the built environment plays an important role in it. On the one hand, impacts of building design, construction, operation and management of hospitals on environment and health are currently accepted. On the other hand, hospitals are complex systems, where changes are neither fast nor easily performed. In order to achieve a green healthcare system, a deep knowledge of its strengths and weaknesses is needed, as well as of the internal dynamics. According to this target, our research focuses on the identification of opportunities for improving the existing health facilities according to the new concepts related to green hospitals. We deal with the study of various aspects as the site and its environment, better access, efficient management of resources (particularly water and energy), waste reduction, use of renewable and low emission materials, as well as all factors in design that can improve the users’ wellness. Some decisions must be taken at the early phases of planning, design, and construction, while other can be reached when hospitals are already operating. In addition, some decisions affect the buildings and their sites (the ecological footprint of the facility), while other extend to the neighbouring communities (districts, and municipal infrastructures and services) in order to diminish the risks, and to protect natural resources. Decisions can even affect wider ranges (as supplies and purchasing, for instance) and can help the efficient management while reducing the environment degradation. The proposed case study is University Hospital Príncipe de Asturias in Alcalá de Henares

Exact Solution of a Electron System Combining Two Different t-J Models

A new strongly correlated electron model is presented. This is formed by two types of sites: one where double occupancy is forbidden, as in the t-J model, and the other where double occupancy is allowed but vacancy is not allowed, as an inverse t-J model. The Hamiltonian shows nearest and next-to-nearest neighbour interactions and it is solved by means of a modified algebraic nested Bethe Ansatz. The number of sites where vacancy is not allowed, may be treated as a new parameter if the model is looked at as a t-J model with impurities. The ground and excited states are described in the thermodynamic limit.Comment: Some corrections and references added. To be published in J. Phys.

Integrability of a t-J model with impurities

A t-J model for correlated electrons with impurities is proposed. The impurities are introduced in such a way that integrability of the model in one dimension is not violated. The algebraic Bethe ansatz solution of the model is also given and it is shown that the Bethe states are highest weight states with respect to the supersymmetry algebra gl(2/1)Comment: 14 page