7,954 research outputs found
Continuity of the Alvarez class under deformations
A foliated manifold (M,F) is minimizable if there exists a Riemannian metric
g on M such that every leaf of F is a minimal submanifold of (M,g). Alvarez
Lopez defined a cohomology class of degree 1 called the Alvarez class of (M,F)
whose triviality characterizes the minimizability of (M,F), when M is closed
and F is Riemannian. In this paper, we show that the family of the Alvarez
classes of a smooth family of Riemannian foliations is continuous with respect
to the parameter. Since the Alvarez class has algebraic rigidity under certain
topological conditions on (M,F) as the author showed in arXiv:0909.1125, we
show that the minimizability of Riemannian foliations is invariant under
deformation under the same topological conditions.Comment: 31 pages, 2 figures, to appear in J. Reine. Angew. Math.. Proposition
6 was added to correct a mistake in the paragraph after Question 5. Minor
corrections on grammar have also been mad
Structure and functions of fungal cell surfaces
A review with 24 references on the biochemistry, molecular structure, and function of cell surfaces of fungi, especially dermatophytes: the chemistry and structure of the cell wall, the effect of polyene antibiotics on the morphology and function of cytoplasmic membranes, and the chemical structure and function of pigments produced by various fungi are discussed
Positive mass theorem in extended supergravities
Following the Witten-Nester formalism, we present a useful prescription using
Weyl spinors towards the positivity of mass. As a generalization of
arXiv:1310.1663, we show that some "positivity conditions" must be imposed upon
the gauge connections appearing in the supercovariant derivative acting on
spinors. A complete classification of the connection fulfilling the positivity
conditions is given. It turns out that these positivity conditions are indeed
satisfied for a number of extended supergravity theories. It is shown that the
positivity property holds for the Einstein-complex scalar system, provided that
the target space is Hodge-Kahler and the potential is expressed in terms of the
superpotential. In the Einstein-Maxwell-dilaton theory with a dilaton
potential, the dilaton coupling function and the superpotential are fixed by
the positive mass property. We also explore the gauged supergravity and
demonstrate that the positivity of the mass holds independently of the gaugings
and the deformation parameters.Comment: v2: 22 pages, typos fixed and refs added, a section discussing the
Einstein-Maxwell-dilaton theory added, an appendix classifies the connection
satisfying positivity conditions, accepted for publication in NP
Oil Palm Production and Cooperatives in the Philippines
The promotion of oil palm production as an agribusiness development policy is a major issue in response to the increasing demand of palm oil in the Philippines. This paper focused on oil palm production cooperatives composed of agrarian reform beneficiaries (ARBs) as members who were granted the Certificate of Land Ownership Award (CLOA). The paper scrutinized the difference of farm incomes with the land titles between the Individual CLOA and the Collective CLOA under the Agribusiness Venture Arrangement (AVA) mode through the field survey of the cooperatives in the provinces in Mindanao. In conclusion, the proposal was made with the emphasis on the necessity to provide production technology and management skill to the cooperatives and its ARBs members with the special emphasis given to those granted the Collective CLOA through the various kinds of agricultural assistance.
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