925 research outputs found
A Spin-1/2 Model for CsCuCl_3 in an External Magnetic Field
CsCuCl_3 is a ferromagnetically stacked triangular spin-1/2 antiferromagnet.
We discuss models for its zero-temperature magnetization process. The models
range from three antiferromagnetically coupled ferromagnetic chains to the full
three-dimensional situation. The situation with spin-1/2 is treated by
expansions around the Ising limit and exact diagonalization. Further,
weak-coupling perturbation theory is used mainly for three coupled chains which
are also investigated numerically using the density-matrix renormalization
group technique. We find that already the three-chain model gives rise to the
plateau-like feature at one third of the saturation magnetization which is
observed in magnetization experiments on CsCuCl_3 for a magnetic field
perpendicular to the crystal axis. For a magnetic field parallel to the crystal
axis, a jump is observed in the experimental magnetization curve in the region
of again about one third of the saturation magnetization. In contrast to
earlier spinwave computations, we do not find any evidence for such a jump with
the model in the appropriate parameter region.Comment: 13 pages LaTeX2e with EPJ macro package (included), 8 (e)ps figures
included using psfig.sty; this is the final version to appear in Eur. Phys. J
B; a few further explanations and one reference adde
Note on the occurrence of a terrestrial isopod, Hemilepistus klugii (Brandt) in Baluchistan, Pakistan
During a computer-aided search of the Crustacea collection in the Department of Invertebrate Zoology at the Smithsonian Institution (USNM), a record was found for the existence of Hemilepistus klugii (Brandt, 1833) in Pakistan
An illustrated key to Malacostraca (Crustacea) of the Northern Arabian Sea part-V: Isopoda
The northern Arabian Sea Isopod fauna is keyed out, excluding the gulfs fauna. Some terrestrial species are also included. Previous accounts and recent collections
from Pakistan mainly at Karachi have turned up 7 suborders, 18 families, 76 genera and 12 1 species. There 5 are new records from Pakistan. For each species, there is an
illustration and information of its reporter from the area and on its host, if parastic. The source of illustration is also given
Project zandwinning: monitoring van de impact van de zandwinningen op de morfologie van the banken
Multi time and space scale monitoring of the sand extraction and its impact on the seabed by coupling EMS data and MBES measurements
Issues of Application Design for Social Studies
The given paper presents the relevant problem of software design for social welfare researches oriented towards the life satisfaction and other psychology studies which are important for social development. The aim of this paper is to show most important issues which can complicate application of algorithms and software for social studies e.g. testing and interviewing results analysis. It summarizes the elements of the Data Mining concepts which are vital for processing big amount of complex data characterized with weak mathematical formalization (as results of sociological studies). This article also includes description of requirements for software systems meant to be implemented in social studies and names existing software decisions in order to show their limitations. This allows us to conclude that this software implementations can be expanded and coordinated by means of new information system, created especially for solving this problem. And also includes short description of "MultiTest" web-portal designed to solve a number of problems associated with the social studies
The ETS transcription factor Spi-B is required for human plasmacytoid dendritic cell development
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