1,362 research outputs found
More three-point correlators of giant magnons with finite size
In the framework of the semiclassical approach, we compute the normalized
structure constants in three-point correlation functions, when two of the
vertex operators correspond to heavy string states, while the third vertex
corresponds to a light state. This is done for the case when the heavy string
states are finite-size giant magnons with one or two angular momenta, and for
two different choices of the light state, corresponding to dilaton operator and
primary scalar operator. The relevant operators in the dual gauge theory are
Tr(F_{\mu\nu}^2 Z^j+...) and Tr(Z^j). We first consider the case of AdS_5 x S^5
and N = 4 super Yang-Mills. Then we extend the obtained results to the
gamma-deformed AdS_5 x S^5_\gamma, dual to N = 1 super Yang-Mills theory,
arising as an exactly marginal deformation of N = 4 super Yang-Mills.Comment: 14 pages, no figure
Effect of correlations on network controllability
A dynamical system is controllable if by imposing appropriate external
signals on a subset of its nodes, it can be driven from any initial state to
any desired state in finite time. Here we study the impact of various network
characteristics on the minimal number of driver nodes required to control a
network. We find that clustering and modularity have no discernible impact, but
the symmetries of the underlying matching problem can produce linear, quadratic
or no dependence on degree correlation coefficients, depending on the nature of
the underlying correlations. The results are supported by numerical simulations
and help narrow the observed gap between the predicted and the observed number
of driver nodes in real networks
Meniscus tear developed by pulling of the anomalous insertion of medial meniscus on anterior cruciate ligament
There is no report regarding a medial meniscus tear arising from an anomalous insertion of medial meniscus on the ACL, which seemed to be developed by the same mechanism as ACL tear. A case of a combined medial meniscus tear with ACL tear in the presence of an anomalous insertion of the medial meniscus on the ACL is reported
Neural development features: Spatio-temporal development of the Caenorhabditis elegans neuronal network
The nematode Caenorhabditis elegans, with information on neural connectivity,
three-dimensional position and cell linage provides a unique system for
understanding the development of neural networks. Although C. elegans has been
widely studied in the past, we present the first statistical study from a
developmental perspective, with findings that raise interesting suggestions on
the establishment of long-distance connections and network hubs. Here, we
analyze the neuro-development for temporal and spatial features, using birth
times of neurons and their three-dimensional positions. Comparisons of growth
in C. elegans with random spatial network growth highlight two findings
relevant to neural network development. First, most neurons which are linked by
long-distance connections are born around the same time and early on,
suggesting the possibility of early contact or interaction between connected
neurons during development. Second, early-born neurons are more highly
connected (tendency to form hubs) than later born neurons. This indicates that
the longer time frame available to them might underlie high connectivity. Both
outcomes are not observed for random connection formation. The study finds that
around one-third of electrically coupled long-range connections are late
forming, raising the question of what mechanisms are involved in ensuring their
accuracy, particularly in light of the extremely invariant connectivity
observed in C. elegans. In conclusion, the sequence of neural network
development highlights the possibility of early contact or interaction in
securing long-distance and high-degree connectivity
Holographic Correlation Functions for Open Strings and Branes
In this paper, we compute holographically the two-point and three-point
functions of giant gravitons with open strings. We consider the maximal giant
graviton in and the string configurations corresponding to the ground
states of Z=0 and Y=0 open spin chain, and the spinning string in AdS
corresponding to the derivative type impurities in Y=0 or Z=0 open spin chain
as well. We treat the D-brane and open string contribution separately and find
the corresponding D3-brane and string configurations in bulk which connect the
composite operators at the AdS boundary. We apply a new prescription to
treat the string state contribution and find agreements for the two-point
functions. For the three-point functions of two giant gravitons with open
strings and one certain half-BPS chiral primary operator, we find that the
D-brane contributions to structure constant are always vanishing and the open
string contribution for the Y=0 ground state is in perfect match with the
prediction in the free field limit.Comment: 25 page
Correlation functions of three heavy operators - the AdS contribution
We consider operators in N=4 SYM theory which are dual, at strong coupling,
to classical strings rotating in S^5. Three point correlation functions of such
operators factorize into a universal contribution coming from the AdS part of
the string sigma model and a state-dependent S^5 contribution. Consequently a
similar factorization arises for the OPE coefficients. In this paper we
evaluate the AdS universal factor of the OPE coefficients which is explicitly
expressed just in terms of the anomalous dimensions of the three operators.Comment: 49 pages, 3 figures; v.2 references corrected; v3: corrected
discussion in section 5, results unchange
The Energy Landscape, Folding Pathways and the Kinetics of a Knotted Protein
The folding pathway and rate coefficients of the folding of a knotted protein
are calculated for a potential energy function with minimal energetic
frustration. A kinetic transition network is constructed using the discrete
path sampling approach, and the resulting potential energy surface is
visualized by constructing disconnectivity graphs. Owing to topological
constraints, the low-lying portion of the landscape consists of three distinct
regions, corresponding to the native knotted state and to configurations where
either the N- or C-terminus is not yet folded into the knot. The fastest
folding pathways from denatured states exhibit early formation of the
N-terminus portion of the knot and a rate-determining step where the C-terminus
is incorporated. The low-lying minima with the N-terminus knotted and the
C-terminus free therefore constitute an off-pathway intermediate for this
model. The insertion of both the N- and C-termini into the knot occur late in
the folding process, creating large energy barriers that are the rate limiting
steps in the folding process. When compared to other protein folding proteins
of a similar length, this system folds over six orders of magnitude more
slowly.Comment: 19 page
Mesoscopic organization reveals the constraints governing C. elegans nervous system
One of the biggest challenges in biology is to understand how activity at the
cellular level of neurons, as a result of their mutual interactions, leads to
the observed behavior of an organism responding to a variety of environmental
stimuli. Investigating the intermediate or mesoscopic level of organization in
the nervous system is a vital step towards understanding how the integration of
micro-level dynamics results in macro-level functioning. In this paper, we have
considered the somatic nervous system of the nematode Caenorhabditis elegans,
for which the entire neuronal connectivity diagram is known. We focus on the
organization of the system into modules, i.e., neuronal groups having
relatively higher connection density compared to that of the overall network.
We show that this mesoscopic feature cannot be explained exclusively in terms
of considerations, such as optimizing for resource constraints (viz., total
wiring cost) and communication efficiency (i.e., network path length).
Comparison with other complex networks designed for efficient transport (of
signals or resources) implies that neuronal networks form a distinct class.
This suggests that the principal function of the network, viz., processing of
sensory information resulting in appropriate motor response, may be playing a
vital role in determining the connection topology. Using modular spectral
analysis, we make explicit the intimate relation between function and structure
in the nervous system. This is further brought out by identifying functionally
critical neurons purely on the basis of patterns of intra- and inter-modular
connections. Our study reveals how the design of the nervous system reflects
several constraints, including its key functional role as a processor of
information.Comment: Published version, Minor modifications, 16 pages, 9 figure
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