Large-UU limit of a Hubbard model in a magnetic field: chiral spin interactions and paramagnetism

We consider the large-$U$ limit of the one-band Hubbard model at half-filling on a non-bipartite two-dimensional lattice. An external magnetic field can induce a three-spin chiral interaction at order $1 / U^2 ~$. We discuss situations in which, at low temperatures, the chiral term may have a larger effect than the Pauli coupling of electron spins to a magnetic field. We present a model which explicitly demonstrates this. The ground state is a singlet with a gap; hence the spin susceptibility is zero while the chiral susceptibility is finite and paramagnetic.Comment: 12 pages, plain TeX, one figure available on request, to appear in Phys. Rev.

Investigation of the atmospheric and surface ocean pCO/sub 2/ in the Indian Ocean. Final technical report

The results of measurements for the concentration of CO/sub 2/ in the marine air and the partial pressure of CO/sub 2/ (pCO/sub 2/) in the surface ocean water obtained during the Geosecs Expedition in the north and south Indian Oceans, December 1977 through April 1978 are summarized. The area studied covers 13/sup 0/N to 64/sup 0/S in latitudes and 55/sup 0/E to 115/sup 0/E in longitudes. It has been found that the atmospheric CO/sub 2/ concentration in the southern hemisphere south of 15/sup 0/S is remarkably constant at 334 +- ppM (expressed as mole fraction of CO/sub 2/ in dry air) throughout the period of this investigation. The CO/sub 2/ concentration in the northern hemisphere from the equator to 13/sup 0/N exceeds that in the southern hemisphere by up to 5 ppM. The Inter-Tropical Convergence Zone (ITCZ) appears to represent a transition zone for the atmosphere CO/sub 2/ distribution. The surface water pCO/sub 2/ values in the Indian Ocean range from 300 microatm. to 360 microatm. The highest values were observed in the Arabian Sea, and appear to be due to the low alkalinity water flowing out of the Red Sea. The Indian equatorial water has a maximum pCO/sub 2/ value of about 335 microatm., which is about 10 microatm. (or 3%) greater than that in the atmosphere. The Indian Ocean data were combined with those previously obtained in the Pacific and Atlantic Oceans to yield a global mean pCO/sub 2/ value for the surface ocean water. It is found that the global mean pCO/sub 2/ for the world oceans is 10 +- 8 microatm. lower than the mean atmospheric pCO/sub 2/ value. This indicates that the net transfer rate of CO/sub 2/ from the atmosphere to the oceans corresponds to 50 (+-40)% of the industrial CO/sub 2/ production rate

Šiuolaikinė vadyba

The 21th c. witnesses rapid democratisation and development processes and their results – the global economy and market, the development of which directly depends on global natural, material, financial and human resources. Lithuanian and foreign scientists have not substantially analysed the methodology of activity optimisation and its implementation in the context of the 21st century’s economy and market, which would guarantee the speed of development of democracy and progress in Lithuania, and the results of the sustainable state and society would guarantee at least average standard of living for its residents. With the application of effective management aimed at activity optimisation and use of other states’ experience, a project of development of a sustainable state and society could be achieved by only changing the Constitution of the Republic of Lithuania which would guarantee the actual implementation of the project in Lithuania. The aim of the research is to analyse theoretical and practical possibilities for the development of a sustainable state and society and application thereof in Lithuania. The work presents the methodology of the optimisation of activities and its implementation methodology. The work also seeks to systemise results of the development of other states, to summarise them and compare with the current situation in Lithuania as well as to specify the key directions and preconditions for drafting the project of the development of a sustainable state and society in line with the Constitution, to submit conclusions, which could help optimise activities, to improve the standard of living and the quality of life in Lithuania, the EU and the global community

An Application of Stochastic Ordering to the Analysis of the Push-Out Mechanism

this paper, we compute the stochastic bounds on the cell loss rates in an ATM switch. The spatial priority in the buffer is controlled by the Push-Out mechanism, while the time priority is managed in the FIFO manner. We consider an i.i.d arrival process of cells and a constant switching time of a cell. Therefore, the system can be modelled by a discret-time Markov chain, however the size of the chain is approximatively