4,144 research outputs found
Finite number of Kaluza-Klein modes, all with zero masses
Kaluza-Klein modes of fermions in a 5-dimensional toy model are considered.
The number of Kaluza-Klein modes that survive after integration over extra
dimensions is finite in this space. Moreover the extra dimensional piece of the
kinetic term induces no mass for the higher Kaluza-Klein modes on contrary to
the standard lore.Comment: Presentation is improved and typos are corrected, two appendices and
some references are added. No change in the essential content of the paper.
11 page
Design of artificial genetic regulatory networks with multiple delayed adaptive responses
Genetic regulatory networks with adaptive responses are widely studied in
biology. Usually, models consisting only of a few nodes have been considered.
They present one input receptor for activation and one output node where the
adaptive response is computed. In this work, we design genetic regulatory
networks with many receptors and many output nodes able to produce delayed
adaptive responses. This design is performed by using an evolutionary algorithm
of mutations and selections that minimizes an error function defined by the
adaptive response in signal shapes. We present several examples of network
constructions with a predefined required set of adaptive delayed responses. We
show that an output node can have different kinds of responses as a function of
the activated receptor. Additionally, complex network structures are presented
since processing nodes can be involved in several input-output pathways
Autonomous Learning by Simple Dynamical Systems with Delayed Feedbacks
A general scheme for construction of dynamical systems able to learn
generation of the desired kinds of dynamics through adjustment of their
internal structure is proposed. The scheme involves intrinsic time-delayed
feedback to steer the dynamics towards the target performance. As an example, a
system of coupled phase oscillators, which can by changing the weights of
connections between its elements evolve to a dynamical state with the
prescribed (low or high) synchronization level, is considered and investigated
Warped Kaluza-Klein Towers Revisited
Inspired by the warped Randall Sundrum scenario proposed to solve the mass
scale hierarchy problem with a compactified fifth extra dimension, a similar
model with no metric singularities has been elaborated. In this framework, the
Kaluza-Klein reduction equations for a real massless scalar field propagating
in the bulk have been studied carefully from the point of view of hermiticity
so as to formulate in a mathematically rigorous way all the possible boundary
conditions and corresponding mass eigenvalue towers and tachyon states. The
physical masses as observable in our four-dimensional brane are deduced from
these mass eigenvalues depending on the location of the brane on the extra
dimension axis. Examples of mass towers and tachyons and related field
probability densities are presented from numerical computations performed for
some arbitrary choices of the parameters of the model.Comment: 34 pages, 5 figure
Evaluation of photogrammetric flight under icing conditions on March 23, 1978
In a double passage through a route laid out in a stagnation zone of the Bavarian forest, it was found that the stagnation and attendant elevation increases the danger of icing. Conversely, it turned out that formation of precipitation reduces the icing intensity. A comparison of both factors showed: the reduction of ice formation through precipitation equals the increase due to stagnation, or even exceeds it
Identifying Key Sectors in the Regional Economy: A Network Analysis Approach Using Input-Output Data
By applying network analysis techniques to large input-output system, we
identify key sectors in the local/regional economy. We overcome the limitations
of traditional measures of centrality by using random-walk based measures, as
an extension of Blochl et al. (2011). These are more appropriate to analyze
very dense networks, i.e. those in which most nodes are connected to all other
nodes. These measures also allow for the presence of recursive ties (loops),
since these are common in economic systems (depending to the level of
aggregation, most firms buy from and sell to other firms in the same industrial
sector). The centrality measures we present are well suited for capturing
sectoral effects missing from the usual output and employment multipliers. We
also develop an R package (xtranat) for the processing of data from IMPLAN(R)
models and for computing the newly developed measures
Threshold production of meta-stable bound states of Kaluza Klein excitations in Universal Extra Dimensions
We study the formation and detection at the next linear e^+e^- collider of
bound states of level-1 quark Kaluza-Klein excitations B_KK within a scenario
of universal extra-dimensions (UED). The interactions of such Kaluza-Klein
excitations are modeled by an alpha_s driven Coulomb potential. In order to
obtain the threshold cross-section, we employ the Green function method which
is known to properly describe the peaks below threshold and to yield a net
increase in the continuum region (above threshold) relative to the naive Born
cross-section. We study such effect at different values of the scale (R^-1) of
the extra-dimensions with an explicit calculation of the mass spectrum as given
by radiative corrections. The overall effect is roughly 2.7 at R^-1=300 GeV and
goes down to 2.2 at R^-1=1000 GeV and a relatively large number of events is
expected from N_events ~ 2.5*10^4 at R^-1=300 GeV down to N_events ~ 10^3 at
R^-1=1000 GeV at the anticipated annual integrated luminosity of L_0= 100
fb^-1. We finally discuss some potentially observable signatures such as the
multilepton channels 2j + 2l + missing energy, and 2j + 4l + missing energy for
which we estimate statistical significance >~ 2 for R^-1 up to 600 ~ 700 GeV.Comment: Accepted for publication in Phys. Rev. D. Enhanced version. 13 pages,
5 figures, 2 table
Dynamical Fermion Masses Under the Influence of Kaluza-Klein Fermions and a Bulk Abelian Gauge Field
The dynamical fermion mass generation on a 3-brane in the 5D space-time is
discussed in a model with bulk fermions in interaction with fermions on the
brane assuming the presence of a constant abelian gauge field component
in the bulk. We calculate the effective potential as a function of the fermion
masses and the gauge field component . The masses can be found from the
stationarity condition for the effective potential (the gap equation). We
formulate the equation for the mass spectrum of the 4D--fermions. The phases
with finite and vanishing fermion masses are studied and the dependence of the
masses on the radius of the 5th dimension is analyzed. The influence of the
-component of the gauge field on the symmetry breaking is considered both
when this field is a background parameter and a dynamical variable. The
critical values of the field, the coupling constant and the radius are
examined.Comment: 9 pages, 4 figure
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