7,115 research outputs found
The high-temperature expansion of the classical Ising model with S_z^2 term
We derive the high-temperature expansion of the Helmholtz free energy up to
the order \beta^{17} of the one-dimensional spin-S Ising model, with single-ion
anisotropy term, in the presence of a longitudinal magnetic field. We show that
the values of some thermodynamical functions for the ferromagnetic models, in
the presence of a weak magnetic field, are not small corrections to their
values with h=0. This model with S=3 was applied by Kishine et al. [J.-i.
Kishine et al., Phys. Rev. B, 2006, 74, 224419] to analyze experimental data of
the single-chain magnet [Mn (saltmen)]_2 [Ni(pac)_2 (py)_2] (PF_6)_2 for T<40
K. We show that for T<35 K the thermodynamic functions of the large-spin limit
model are poor approximations to their analogous spin-3 functions.Comment: 10 pages, 3 figure
The hidden curriculum in medical teaching
Indexación: Web of Science; ScieloBackground: Medical education must ascribe to a curriculum but clinical teaching poses special difficulties that go beyond any programming attempt. Attitudes and skills learned during tutored clinical practice are called the "hidden curriculum". The figure and personal features of the teacher, his environment and the atmosphere that projects every particular medical school, are essential to shape the characteristics of the student. Paradoxically, it is almost impossible to measure the impact of this hidden curriculum. This article is a reflection on an issue that is acquiring special relevance in medical education.http://ref.scielo.org/x49wb
Effect of the Canting of Local Anisotropy Axes on Ground-State Properties of a Ferrimagnetic Chain with Regularly Alternating Ising and Heisenberg Spins
The effect of the canting of local anisotropy axes on the ground-state phase
diagram and magnetization of a ferrimagnetic chain with regularly alternating
Ising and Heisenberg spins is exactly examined in an arbitrarily oriented
magnetic field. It is shown that individual contributions of Ising and
Heisenberg spins to the total magnetization basically depend on the spatial
orientation of the magnetic field and the canting angle between two different
local anisotropy axes of the Ising spins.Comment: 3 pages, 3 figure
Thermodynamics of the quantum spin-S XXZ chain
The thermodynamics of the spin- anisotropic quantum chain with
arbitrary value of and unitary norm, in the high-temperature regime, is
reported. The single-ion anisotropy term and the interaction with an external
magnetic field in the -direction are taken into account. We obtain, for
arbitrary value of , the -expansion of the Helmholtz free energy of
the model up to order and show that it actually depends on
. Its classical limit is obtained by simply taking . At and D=0, our high temperature expansion of the classical
model coincides with Joyce's exact solution\cite{joyce_prl}. We study, in the
high temperature region, some thermodynamic quantities such as the specific
heat and the magnetic susceptibility as functions of spin and verify for which
values of those thermodynamic functions behave classically. Their finite
temperature behavior is inferred from interpolation of their high- and
low-temperature behavior, and shown to be in good agreement with numerical
results. The finite temperature behavior is shown for higher values of spin.Comment: 18 pages, 14 figure
Breeding Quality Protein Maize (QPM): Protocols for Developing QPM Cultivars
This manual is intended for maize breeders who would like to start developing quality protein maize (QPM) cultivars. It is a compilation and consolidation of several breeding protocols successfully used at CIMMYT over two decades of QPM development and breeding. A brief background and the basic theory of QPM genetics are explained, leading up to detailed methods and procedures of QPM development.Zea mays, Plant breeding, Breeding methods, Genetic resources, Protein quality, Protein content, Application methods, Lysine, Tryptophan, Food composition, Crop Production/Industries, F30, Q04,
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