32 research outputs found
Einstein Geometrization Philosophy and Differential Identities in PAP-Geometry
The importance of Einstein's geometrization philosophy, as an alternative to
the least action principle, in constructing general relativity (GR), is
illuminated. The role of differential identities in this philosophy is
clarified. The use of Bianchi identity to write the field equations of GR is
shown. Another similar identity in the absolute parallelism geometry is given.
A more general differential identity in the parameterized absolute parallelism
geometry is derived. Comparison and interrelationships between the above
mentioned identities and their role in constructing field theories are
discussed.Comment: LaTeX file, 17 pages, comments and criticism are welcom
Teleparallel Lagrange Geometry and a Unified Field Theory
In this paper, we construct a field theory unifying gravity and
electromagnetism in the context of Extended Absolute Parallelism (EAP-)
geometry. This geometry combines, within its structure, the geometric richness
of the tangent bundle and the mathematical simplicity of Absolute Parallelism
(AP-) geometry. The constructed field theory is a generalization of the
Generalized Field Theory (GFT) formulated by Mikhail and Wanas. The theory
obtained is purely geometric. The horizontal (resp. vertical) field equations
are derived by applying the Euler-Lagrange equations to an appropriate
horizontal (resp. vertical) scalar Lagrangian. The symmetric part of the
resulting horizontal (resp. vertical) field equations gives rise to a
generalized form of Einstein's field equations in which the horizontal (resp.
vertical) energy-momentum tensor is purely geometric. The skew-symmetric part
of the resulting horizontal (resp. vertical) field equations gives rise to a
generalized form of Maxwell equations in which the electromagnetic field is
purely geometric. Some interesting special cases, which reveal the role of the
nonlinear connection in the obtained field equations, are examined. Finally,
the condition under which our constructed field equations reduce to the GFT is
explicitly established.Comment: Latex file, 33 page
On Finslerized Absolute Parallelism spaces
The aim of the present paper is to construct and investigate a Finsler
structure within the framework of a Generalized Absolute Parallelism space
(GAP-space). The Finsler structure is obtained from the vector fields forming
the parallelization of the GAP-space. The resulting space, which we refer to as
a Finslerized Parallelizable space, combines within its geometric structure the
simplicity of GAP-geometry and the richness of Finsler geometry, hence is
potentially more suitable for applications and especially for describing
physical phenomena. A study of the geometry of the two structures and their
interrelation is carried out. Five connections are introduced and their torsion
and curvature tensors derived. Some special Finslerized Parallelizable spaces
are singled out. One of the main reasons to introduce this new space is that
both Absolute Parallelism and Finsler geometries have proved effective in the
formulation of physical theories, so it is worthy to try to build a more
general geometric structure that would share the benefits of both geometries.Comment: Some references added and others removed, PACS2010, Typos corrected,
Amendemrnts and revisions performe
Phytochemical composition and antimicrobial properties of Markhamia platycalyx (Baker) Sprague leaf
Purpose: To isolate new antimicrobial agents from the leaves of Markhamia platycalyx (Baker) Sprague and assess their phytochemical characteristics and antimicrobial activity.
Methods: Different chromatographic and spectroscopic techniques (NMR and ESI-MS) were applied for the identification of antimicrobial compounds. Agar-well diffusion technique was used for determination of antimicrobial activity. Anti-HCV effects were investigated using VITROS Anti-HCV assay.
Results: Eighteen compounds were isolated for the first time from this genus. These were phytol, noctacosanoic acid (OCTA), tormentic acid and β-sitosterol-3-O-(6'-O-heptadecanoyl)-β-Dglucopyranoside. The other compounds were β-sitosterol, ursolic acid (URSA), oleanolic acids, pomolic acid (POMA), 2-epi-tormentic and β-sitosterol-3-O-β-D-glucopyranoside. However, stigmasterol and acteoside, which were seen in previous studies, were also present. Total ethanol extract (TEE) was the most effective against Escherichia coli, with the lowest minimum inhibitory concentration (MIC) of 1.0 µg/mL. Acteoside, URSA and 2-epi-tormentic acid showed the highest antibacterial effect on Pseudomonas aeruginosa while 2-epi-tormentic acid and acteoside produced the least MIC on Candida glabrata. These effects were superior to those produced by standard antibiotics. However, 2-epitormentic acid and β-sitosterol-3-O-β-D-glucopyranoside had no anti-HCV effects.
Conclusion: Due to the good antimicrobial properties of Markhamia platycalyx, it is a potential source of new antimicrobial drugs
Energy-Momentum Complex in M\o ller's Tetrad Theory of Gravitation
M\o ller's Tetrad Theory of Gravitation is examined with regard to the
energy-momentum complex. The energy-momentum complex as well as the
superpotential associated with M\o ller's theory are derived. M\o ller's field
equations are solved in the case of spherical symmetry. Two different
solutions, giving rise to the same metric, are obtained. The energy associated
with one solution is found to be twice the energy associated with the other.
Some suggestions to get out of this inconsistency are discussed at the end of
the paper.Comment: LaTeX2e with AMS-LaTeX 1.2, 13 page
Unification Principle and a Geometric Field Theory
In the context of the geometrization philosophy,
a covariant field theory is constructed. The theory satisfies
the unification principle. The field equations of the
theory are constructed depending on a general differential
identity in the geometry used. The Lagrangian scalar
used in the formalism is neither curvature scalar nor torsion
scalar, but an alloy made of both, the W-scalar. The
physical contents of the theory are explored depending on
different methods. The analysis shows that the theory is
capable of dealing with gravity, electromagnetism and material
distribution with possible mutual interactions. The
theory is shown to cover the domain of general relativity
under certain conditions