7,458 research outputs found
Trajectories in a space with a spherically symmetric dislocation
We consider a new type of defect in the scope of linear elasticity theory,
using geometrical methods. This defect is produced by a spherically symmetric
dislocation, or ball dislocation. We derive the induced metric as well as the
affine connections and curvature tensors. Since the induced metric is
discontinuous, one can expect ambiguity coming from these quantities, due to
products between delta functions or its derivatives, plaguing a description of
ball dislocations based on the Geometric Theory of Defects. However, exactly as
in the previous case of cylindric defect, one can obtain some well-defined
physical predictions of the induced geometry. In particular, we explore some
properties of test particle trajectories around the defect and show that these
trajectories are curved but can not be circular orbits.Comment: 11 pages, 3 figure
Renormalization of the N=1 Abelian Super-Chern-Simons Theory Coupled to Parity-Preserving Matter
We analyse the renormalizability of an Abelian N=1 super-Chern-Simons model
coupled to parity-preserving matter on the light of the regularization
independent algebraic method. The model shows to be stable under radiative
corrections and to be gauge anomaly free.Comment: Latex, 7 pages, no figure
Erupted Complex Odontoma Mimicking a Mandibular Second Molar
Complex odontoma (CO) is considered one of the most common odontogenic lesions, composed by a miscellaneous of dental tissue such as enamel, dentin, pulp and sometimes cementum. They may interfere with the eruption of an associated tooth, being more prevalent in the posterior mandible. CO has been rarely reported as erupted, being considered an intraosseous lesion. This is a case report of a 17-year-old male with a benign fibro-osseous lesion consistent with CO that was located at the left second molar region, above the crown of the impacted mandibular second molar tooth. The lesion was surgically removed, and the tooth had to be extracted, since there was no indication that it could erupt naturally or with orthodontic traction. The histopathological examination confirmed the diagnosis of CO and after 6 months complete bone formation was observed radiographically. An early diagnosis will provide a better treatment option, avoiding tooth extraction or a more damaging surgery
Super-QED and the dimensional reduction of super-{QED}
In this work the supersymmetric gauge invariant action for the massive
Abelian super-{\QED} in the Atiyah-Ward space-time ({\DDdd}) is
formulated. The questions concerning the scheme of the gauge invariance in
{\DDdd} by means of gauging the massive super-{\QED} are
investigated. We study how to ensure the gauge invariance at the expenses of
the introduction of a complex vector superfield. We discuss the Wess-Zumino
gauge and thereupon we conclude that in this gauge, only the imaginary part of
the complex vector field, B_{\m}, gauges a -symmetry, whereas its real
part gauges a Weyl symmetry. We build up the gauge invariant massive term by
introducing a pair of chiral and anti-chiral superfields with opposite
-charges. We carry out a dimensional reduction {\it{\`a la}} Scherk of
the massive super-{\QED} action from {\DDdd} to {\Ddd}. Truncations
are needed in order to suppress non-physical modes and one ends up with a
parity-preserving super-QED (rather than ) in
. Finally, we show that the super-QED we have
got is the supersymmetric version ofthe QED .Comment: 23 pages, latex, no figure
Gauge Theories with Lorentz-Symmetry Violation by Symplectic Projector Method
The violation of Lorentz symmetry is studied from the point of view of a
canonical formulation. We make the usual analysis on the constraints structure
of the Carroll-Field-Jackiw model. In this context we derive the equations of
motion for the physical variables and check out the dispersion relations
obtained from them. Therefore, by the analysis using Symplectic Projector
Method (SPM), we can check the results about this type of Lorentz breaking with
those in the recent literature: in this sense we can confirm that the
configuration of space-like is stable, and the time-like
carry tachionic modes.Comment: 7 pages and no figure
Efeitos da desidratação e do armazenamento em sementes de Taluma ovata St. Hill. - magnoliaceae.
Resumo
Padrão de venação de Psychotria ipecacuanha) (Brot.) Stokes - (Rubiaceae).
Poaia ou ipeca (Psychotria ipecacuanha (Brot.) Stokes.-Rubiaceae) apesar de seu valor farmacológico e sócio-econômico é cada vez menos freqüente no seu habitat. O trabalho em foco consiste no estudo de diafanização da espécie em questão a qual foi coletada no Banco Ativo de Germoplasma de Ipeca cultivada no Horto de Plantas Medicinais da Embrapa Amazônia Oriental. A espécie citada apresenta-se como levogira, com várias redes de nervuras, sendo classificada como broquidódroma, e ao longo das folhas observam-se algumas estruturas secretoras. A descrição morfológica facilitará a identificação de espécies pertencentes ao mesmo gênero
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