23,430 research outputs found
On induced birefringence in viscoelastic materials
Describing induced birefringence in viscoelastic materials based on constitutive assumptions for stress and dielectric propertie
Radiographic measurements of the trachea in domestic short haired and Persian cats
Tracheal diameter can be assessed from a thoracic radiograph, with assessment of tracheal diameter in dogs based on ratios between tracheal diameter and a skeletal measurement – however reference ranges are not available for the cat. Tracheal narrowing may cause significant clinical problems, although tracheal hypoplasia in dogs may be clinically silent, and is rarely reported in cats (both mesati- and brachycephalic). The tracheal diameter and trachea:thoracic inlet and trachea:rib ratios were calculated for populations of Domestic Short Haired (DSH) (n=68) and Persian (n=40) cats. This gave reference ranges for radiographic tracheal measurements in these breeds. It is proposed that the tracheal diameter in a normal DSH cat should be 18% of the diameter of the thoracic inlet, and compared to 20% in Persian cats
Quantum Fermion Hair
It is shown that the Dirac operator in the background of a magnetic
%Reissner-Nordstr\"om black hole and a Euclidean vortex possesses normalizable
zero modes in theories containing superconducting cosmic strings. One
consequence of these zero modes is the presence of a fermion condensate around
magnetically charged black holes which violates global quantum numbers.Comment: 16pp (harvmac (l)) and 2 figs.(not included
Reentrant violation of special relativity in the low-energy corner
In the effective relativistic quantum field theories the energy region, where
the special relativity holds, can be sandwiched from both the high and low
energies sides by domains where the special relativity is violated. An example
is provided by 3He-A where the relativistic quantum field theory emerges as the
effective theory. The reentrant violation of the special relativity in the
ultralow energy corner is accompanied by the redistribution of the
momentum-space topological charges between the fermionic flavors. At this
ultralow energy an exotic massless fermion with the topological charge
arises, whose energy spectrum mixes the classical and relativistic behavior.
This effect can lead to neutrino oscillations if neutrino flavors are still
massless at this energy scale.Comment: RevTeX file, 5 pages, one figure, submitted to JETP Let
Minority Becomes Majority in Social Networks
It is often observed that agents tend to imitate the behavior of their
neighbors in a social network. This imitating behavior might lead to the
strategic decision of adopting a public behavior that differs from what the
agent believes is the right one and this can subvert the behavior of the
population as a whole.
In this paper, we consider the case in which agents express preferences over
two alternatives and model social pressure with the majority dynamics: at each
step an agent is selected and its preference is replaced by the majority of the
preferences of her neighbors. In case of a tie, the agent does not change her
current preference. A profile of the agents' preferences is stable if the
preference of each agent coincides with the preference of at least half of the
neighbors (thus, the system is in equilibrium).
We ask whether there are network topologies that are robust to social
pressure. That is, we ask if there are graphs in which the majority of
preferences in an initial profile always coincides with the majority of the
preference in all stable profiles reachable from that profile. We completely
characterize the graphs with this robustness property by showing that this is
possible only if the graph has no edge or is a clique or very close to a
clique. In other words, except for this handful of graphs, every graph admits
at least one initial profile of preferences in which the majority dynamics can
subvert the initial majority. We also show that deciding whether a graph admits
a minority that becomes majority is NP-hard when the minority size is at most
1/4-th of the social network size.Comment: To appear in WINE 201
What can we learn from Dijet suppression at RHIC?
We present a systematic study of the dijet suppression at RHIC using the
VNI/BMS parton cascade. We examine the modification of the dijet asymmetry A_j
and the within-cone transverse energy distribution (jet-shape) along with
partonic fragmentation distributions z and j_t in terms of: qhat; the path
length of leading and sub-leading jets; cuts on the jet energy distributions;
jet cone angle and the jet-medium interaction mechanism. We find that A_j is
most sensitive to qhat and relatively insensitive to the nature of the
jet-medium interaction mechanism. The jet profile is dominated by qhat and the
nature of the interaction mechanism. The partonic fragmentation distributions
clearly show the jet modification and differentiate between elastic and
radiative+elastic modes
High Temperature Superfluid and Feshbach Resonance
We study an effective field theory describing cold fermionic atoms near a
Feshbach resonance. The theory gives a unique description of the dynamics in
the limit that the energy of the Feshbach resonance is tuned to be twice that
of the Fermi surface. We show that in this limit the zero temperature
superfluid condensate is of order the Fermi energy, and obtain a critical
temperature Comment: 9 pages, 3 figures, RevTe
Large QCD at non-zero chemical potential
The general issue of large QCD at nonzero chemical potential is
considered with a focus on understanding the difference between large QCD
with an isospin chemical potential and large QCD with a baryon chemical
potential. A simple diagrammatic analysis analogous to `t Hooft's analysis at
implies that the free energy with a given baryon chemical potential is
equal to the free energy with an isospin chemical potential of the same value
plus corrections. Phenomenologically, these two systems behave quite
differently. A scenario to explain this difference in light of the diagrammatic
analysis is explored. This scenario is based on a phase transition associated
with pion condensation when the isospin chemical potential exceeds ;
associated with this transition there is breakdown of the expansion--in
the pion condensed phase there is a distinct expansion including a
larger set of diagrams. While this scenario is natural, there are a number of
theoretical issues which at least superficially challenge it. Most of these can
be accommodated. However, the behavior of quenched QCD which raises a number of
apparently analogous issues cannot be easily understood completely in terms of
an analogous scenario. Thus, the overall issue remains open
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