178 research outputs found
Some Consequences of Noncommutative Worldsheet of Superstring
In this paper some properties of the superstring with noncommutative
worldsheet are studied. We study the noncommutativity of the spacetime,
generalization of the Poincar\'e symmetry of the superstring, the changes of
the metric, antisymmetric tensor and dilaton.Comment: 11 pages, Latex, no figure, a new action and some references have
been adde
Two Moving-Angled 1-Branes with Electric Fields in a Partially Compact Spacetime
In this article we consider two -branes at angle in the presence of the
background electric fields, in a partially compact spacetime. The branes have
motions along a common direction that is perpendicular to both of them. Using
the boundary state formalism, we calculate their interaction amplitude. Some
special cases of this interaction will be studied in detail.Comment: 10 pages, no figure, Late
Demonstration of vermicules of Babesia species in haemolymph smears of Amblyomma variegatum in Nigeria
The present study was conducted to investigate the presence of developmental stage (s) of Babesia species in Amblyomma variegatum. A total of 137 Amblyomma variegatum ticks (85 males and 52 females) were examined by haemolymph smears. Out of the examined male ticks, there were 41 nymphs and 44 adults. The female ticks were 23 nymphs and 29 engorged adults. Sixteen adult males and nine nymphs were positive for vermicules of Babesia species but only eight femalesshowed structures similar to Babesia vermicules. The present study recommends conducting molecular and experimental studies to confirm the type of Babesia parasite in Amblyomma variegatum tick
Schwinger Effect in Non-parallel D1-branes: A Path Integral Approach
We study the Schwinger effect in a system of non-parallel D1-branes for the
bosonic strings using the path integral formalism. We drive the string pair
creation rate by calculating the one loop vacuum amplitude of the setup in
presence of the background electric filed defined along one of the D1-branes.
We find an angle dependent minimum value for the background field and show that
the decaying of vacuum into string pairs takes place for the field above this
value. It is shown that in limit the vacuum
becomes stable and thus no pair creation occurs
Branes with Background Fields in Boundary State Formalism
Interaction of branes in presence of internal gauge fields is considered by
using the boundary state formalism. This approach enables us to consider the
problems that are not easily accessible to the canonical approach via open
strings. The effects of compactification of some of the dimensions on tori are
also discussed. Also we study the massless state contribution on this
interaction.Comment: 12 pp. No figure
Mixed Branes Interaction in Compact Spacetime
We present a general description of two mixed branes interactions. For this
we consider two mixed branes with dimensions p_1 and p_2, in external field
B_{\mu\nu} and arbitrary gauge fields A^1_{\alpha_1} and A^2_{\alpha_2} on the
world volume of them, in spacetime in which some of its directions are
compactified on circles with different radii. Some examples are considered to
clear these general interactions. Finally contribution of the massless states
on the interactions is extracted. Closed string with mixed boundary conditions
and boundary state formalism, provide useful tools for calculation of these
interactions.Comment: 22 pages, to appear in Nucl. Phys.
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