5,673 research outputs found
Galaxy-CMB and galaxy-galaxy lensing on large scales: sensitivity to primordial non-Gaussianity
A convincing detection of primordial non-Gaussianity in the local form of the
bispectrum, whose amplitude is given by the fNL parameter, offers a powerful
test of inflation. In this paper we calculate the modification of two-point
cross-correlation statistics of weak lensing - galaxy-galaxy lensing and
galaxy-Cosmic Microwave Background (CMB) cross-correlation - due to fNL. We
derive and calculate the covariance matrix of galaxy-galaxy lensing including
cosmic variance terms. We focus on large scales (l<100) for which the shape
noise of the shear measurement becomes irrelevant and cosmic variance dominates
the error budget. For a modest degree of non-Gaussianity, fNL=+/-50,
modifications of the galaxy-galaxy lensing signal at the 10% level are seen on
scales R~300 Mpc, and grow rapidly toward larger scales as \propto R^2. We also
see a clear signature of the baryonic acoustic oscillation feature in the
matter power spectrum at ~150 Mpc, which can be measured by next-generation
lensing experiments. In addition we can probe the local-form primordial
non-Gaussianity in the galaxy-CMB lensing signal by correlating the lensing
potential reconstructed from CMB with high-z galaxies. For example, for
fNL=+/-50, we find that the galaxy-CMB lensing cross power spectrum is modified
by ~10% at l~40, and by a factor of two at l~10, for a population of galaxies
at z=2 with a bias of 2. The effect is greater for more highly biased
populations at larger z; thus, high-z galaxy surveys cross-correlated with CMB
offer a yet another probe of primordial non-Gaussianity.Comment: 21 pages, 30 figure
Preferential attachment renders an evolving network of populations robust against crashes
We study a model for the evolution of chemical species under a combination of
population dynamics on a short time scale and a selection mechanism on a longer
time scale. Least fit nodes are replaced by new nodes whose links are attached
to the nodes of the given network via preferential attachment. In contrast to a
random attachment of newly incoming nodes that was used in previous work, this
preferential attachment mechanism accelerates the generation of a so-called
autocatalytic set after a start from a random geometry and the growth of this
structure until it saturates in a stationary phase in which the whole system is
an autocatalytic set. Moreover, the system in the stationary phase becomes much
more stable against crashes in the population size as compared to random
attachment. We explain in detail in terms of graph theoretical notions which
structure of the resulting network is responsible for this stability.
Essentially it is a very dense core with many loops and less nodes playing the
role of a keystone that prevents the system against crashes almost completely.Comment: 12 pages, 9 figures, 2 table
Map equation for link community
Community structure exists in many real-world networks and has been reported
being related to several functional properties of the networks. The
conventional approach was partitioning nodes into communities, while some
recent studies start partitioning links instead of nodes to find overlapping
communities of nodes efficiently. We extended the map equation method, which
was originally developed for node communities, to find link communities in
networks. This method is tested on various kinds of networks and compared with
the metadata of the networks, and the results show that our method can identify
the overlapping role of nodes effectively. The advantage of this method is that
the node community scheme and link community scheme can be compared
quantitatively by measuring the unknown information left in the networks
besides the community structure. It can be used to decide quantitatively
whether or not the link community scheme should be used instead of the node
community scheme. Furthermore, this method can be easily extended to the
directed and weighted networks since it is based on the random walk.Comment: 9 pages,5 figure
Schwinger Boson Formulation and Solution of the Crow-Kimura and Eigen Models of Quasispecies Theory
We express the Crow-Kimura and Eigen models of quasispecies theory in a
functional integral representation. We formulate the spin coherent state
functional integrals using the Schwinger Boson method. In this formulation, we
are able to deduce the long-time behavior of these models for arbitrary
replication and degradation functions.
We discuss the phase transitions that occur in these models as a function of
mutation rate. We derive for these models the leading order corrections to the
infinite genome length limit.Comment: 37 pages; 4 figures; to appear in J. Stat. Phy
Distance, Growth Factor, and Dark Energy Constraints from Photometric Baryon Acoustic Oscillation and Weak Lensing Measurements
Baryon acoustic oscillations (BAOs) and weak lensing (WL) are complementary
probes of cosmology. We explore the distance and growth factor measurements
from photometric BAO and WL techniques and investigate the roles of the
distance and growth factor in constraining dark energy. We find for WL that the
growth factor has a great impact on dark energy constraints but is much less
powerful than the distance. Dark energy constraints from WL are concentrated in
considerably fewer distance eigenmodes than those from BAO, with the largest
contributions from modes that are sensitive to the absolute distance. Both
techniques have some well determined distance eigenmodes that are not very
sensitive to the dark energy equation of state parameters w_0 and w_a,
suggesting that they can accommodate additional parameters for dark energy and
for the control of systematic uncertainties. A joint analysis of BAO and WL is
far more powerful than either technique alone, and the resulting constraints on
the distance and growth factor will be useful for distinguishing dark energy
and modified gravity models. The Large Synoptic Survey Telescope (LSST) will
yield both WL and angular BAO over a sample of several billion galaxies. Joint
LSST BAO and WL can yield 0.5% level precision on ten comoving distances evenly
spaced in log(1+z) between redshift 0.3 and 3 with cosmic microwave background
priors from Planck. In addition, since the angular diameter distance, which
directly affects the observables, is linked to the comoving distance solely by
the curvature radius in the Friedmann-Robertson-Walker metric solution, LSST
can achieve a pure metric constraint of 0.017 on the mean curvature parameter
Omega_k of the universe simultaneously with the constraints on the comoving
distances.Comment: 15 pages, 9 figures, details and references added, ApJ accepte
Klebsiella pneumoniae Orbital Cellulitis with Extensive Vascular Occlusions in a Patient with Type 2 Diabetes
A 39-year-old woman visited the emergency room complaining of right eye pain and swelling over the preceding three days. The ophthalmologist's examination revealed orbital cellulitis and diabetic retinopathy in the right eye, although the patient had no prior diagnosis of diabetes. It was therefore suspected that she had diabetes and orbital cellulitis, and she was started on multiple antibiotic therapies initially. She then underwent computed tomography scans of the orbit and neck and magnetic resonance imaging of the brain. These studies showed an aggravated orbital cellulitis with abscess formation, associated with venous thrombophlebitis, thrombosis of the internal carotid artery, and mucosal thickening of maxillary sinus with multiple paranasal abscesses. Three days later, initial blood culture grew Klebsiella pneumoniae. She recovered after incision and drainage and antibiotic therapy for 37 days
Adrenal ganglioneuroma with hepatic metastasis
Ganglioneuroma is the most differentiated tumor of neural crest origin and rarely arises in the adrenal gland. Ganglioneuroma is typically known to be benign, but very rarely can metastasize to distant sites. We report a case of a 31-year-old man with a huge adrenal mass with hepatic metastases
NMSSM in gauge-mediated SUSY breaking without domain wall problem
A problem of the gauge-mediated SUSY breaking model is its difficulty to
generate a natural value of mu/Bmu, while the NMSSM is a natural framework to
solve the mu/Bmu problem. The NMSSM in gauge-mediated SUSY breaking in its
original form does not work well since the singlet field cannot develop a
desired vacuum expectation value. It also suffers from the cosmological domain
wall problem. We study an extension of the model to include additional
vector-like matter, which is charged under the hidden QCD. It is shown that
this simple extension solves both the problems. We study phenomenological and
cosmological implications of this extended models. The lightest Higgs mass can
be as large as 130-140 GeV for some model points.Comment: 15 pages; the version to be published in PL
A model of the anisotropic correlation function xi(rp, pi) in redshift space including redshift errors
With the advent of very large volume, wide-angle photometric redshift surveys
like e.g. Pan-STARRS, DES, or PAU, which aim at using the spatial distribution
of galaxies as a means to constrain the equation of state parameter of dark
energy, w_DE, it has become extremely important to understand the influence of
redshift inaccuracies on the measurement. We have developed a new model for the
anisotropic two point large-scale (r > 64 h^-1 Mpc) correlation function
xi(rp,pi), in which nonlinear structure growth and nonlinear coherent infall
velocities are taken into account, and photometric redshift errors can easily
be incorporated. In order to test its validity and investigate the effects of
photometric redshifts, we compare our model with the correlation function
computed from a suite of 50 large-volume, moderate-resolution numerical N-body
simulation boxes, where we can perform the analysis not only in real- and
redshift space, but also simulate the influence of a gaussian redshift error
distribution with an absolute rms of sigma_z= 0.015, 0.03, 0.06, and 0.12,
respectively. We conclude that for the given volume (V_box =2.4 h^-3 Gpc^3) and
number density (n ~ 1.25 10^-4) of objects the full shape of xi(rp,pi) is
modeled accurately enough to use it to derive unbiased constraints on the
equation of state parameter of dark energy w_DE and the linear bias b, even in
the presence of redshift errors of the order of sigma_z = 0.06.Comment: Accepted for publication by MNRA
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