9,059 research outputs found
Tailoring therapy for heart failure: the pharmacogenomics of adrenergic receptor signaling.
Heart failure is one of the leading causes of mortality in Western countries, and ÎČ-blockers are a cornerstone of its treatment. However, the response to these drugs is variable among individuals, which might be explained, at least in part, by genetic differences. Pharmacogenomics is the study of genetic contributions to drug response variability in order to provide evidence for a tailored therapy in an individual patient. Several studies have investigated the pharmacogenomics of the adrenergic receptor system and its role in the context of the use of ÎČ-blockers in treating heart failure. In this review, we will focus on the most significant polymorphisms described in the literature involving adrenergic receptors and adrenergic receptor-related proteins, as well as genetic variations influencing ÎČ-blocker metabolism
The faintest galaxies
We investigate the nature of Ultra Faint dwarf spheroidal galaxies (UF dSphs)
in a general cosmological context, simultaneously accounting for various
"classical" dSphs and Milky Way (MW) properties, including their Metallicity
Distribution Function (MDF). The model successfully reproduces both the
observed [Fe/H]-Luminosity relation and the mean MDF of UFs. According to our
results UFs are the living fossils of H2-cooling minihaloes formed at z>8.5,
i.e. before the end of reionization. They are the oldest and the most dark
matter-dominated (M/L > 100) dSphs in the MW system, with a total mass of M =
10^(7-8) Msun. The model allows to interpret the different shape of UFs and
classical dSphs MDF, along with the frequency of extremely metal-poor stars in
these objects. We discuss the "missing satellites problem" by comparing the UF
star formation efficiencies with those derived for minihaloes in the Via Lactea
simulation.Comment: To appear in the conference proceeding: "First Stars and Galaxies:
Challenges in the Next Decade" . Publisher: American Institute of Physics.
Editors: V. Bromm, D. Whalen, N. Yoshid
Lorentz invariant and supersymmetric interpretation of noncommutative quantum field theory
In this paper, using a Hopf-algebraic method, we construct deformed
Poincar\'e SUSY algebra in terms of twisted (Hopf) algebra. By adapting this
twist deformed super-Poincar\'e algrebra as our fundamental symmetry, we can
see the consistency between the algebra and non(anti)commutative relation among
(super)coordinates and interpret that symmetry of non(anti)commutative QFT is
in fact twisted one. The key point is validity of our new twist element that
guarantees non(anti)commutativity of space. It is checked in this paper for N=1
case. We also comment on the possibility of noncommutative central charge
coordinate. Finally, because our twist operation does not break the original
algebra, we can claim that (twisted) SUSY is not broken in contrast to the
string inspired SUSY in N=1 non(anti)commutative superspace.Comment: 15 pages, LaTeX. v3:One section added, typos corrected, to appear in
Int. J. Mod. Phys.
Partitioning a graph into highly connected subgraphs
Given , a -proper partition of a graph is a partition
of such that each part of induces a
-connected subgraph of . We prove that if is a graph of order
such that , then has a -proper partition with at
most parts. The bounds on the number of parts and the minimum
degree are both best possible. We then prove that If is a graph of order
with minimum degree , where
, then has a -proper partition into at most
parts. This improves a result of Ferrara, Magnant and
Wenger [Conditions for Families of Disjoint -connected Subgraphs in a Graph,
Discrete Math. 313 (2013), 760--764] and both the degree condition and the
number of parts are best possible up to the constant
Looking at cosmic near-infrared background radiation anisotropies
The cosmic infrared background (CIB) contains emissions accumulated over the
entire history of the Universe, including from objects inaccessible to
individual telescopic studies. The near-IR (~1-10 mic) part of the CIB, and its
fluctuations, reflects emissions from nucleosynthetic sources and
gravitationally accreting black holes (BHs). If known galaxies are removed to
sufficient depths the source-subtracted CIB fluctuations at near-IR can reveal
sources present in the first-stars-era and possibly new stellar populations at
more recent times. This review discusses the recent progress in this newly
emerging field which identified, with new data and methodology, significant
source-subtracted CIB fluctuations substantially in excess of what can be
produced by remaining known galaxies. The CIB fluctuations further appear
coherent with unresolved cosmic X-ray background (CXB) indicating a very high
fraction of BHs among the new sources producing the CIB fluctuations. These
observations have led to intensive theoretical efforts to explain the
measurements and their properties. While current experimental configurations
have limitations in decisively probing these theories, their potentially
remarkable implications will be tested in the upcoming CIB measurements with
the ESA's Euclid dark energy mission. We describe the goals and methodologies
of LIBRAE (Looking at Infrared Background Radiation with Euclid), a
NASA-selected project for CIB science with Euclid, which has the potential for
transforming the field into a new area of precision cosmology.Comment: Reviews of Modern Physics, to appea
Generation of the Primordial Magnetic Fields during Cosmological Reionization
We investigate the generation of magnetic field by the Biermann battery in
cosmological ionization fronts, using new simulations of the reionization of
the universe by stars in protogalaxies. Two mechanisms are primarily
responsible for magnetogenesis: i) the breakout of I-fronts from protogalaxies,
and ii) the propagation of I-fronts through the high density neutral filaments
which are part of the cosmic web. The first mechanism is dominant prior to
overlapping of ionized regions (z ~ 7), whereas the second continues to operate
even after that epoch. However, after overlap the field strength increase is
largely due to the gas compression occurring as cosmic structures form. As a
consequence, the magnetic field at z ~ 5 closely traces the gas density, and it
is highly ordered on megaparsec scales. The mean mass-weighted field strength
is B_0 ~ 10^{-19} G in the simulation box. There is a relatively well-defined,
nearly linear correlation between B_0 and the baryonic mass of virialized
objects, with B_0 ~ 10^{-18} G in the most massive objects (M ~ 10^9 M_sun) in
our simulations. This is a lower limit, as lack of numerical resolution
prevents us from following small scale dynamical processes which could amplify
the field in protogalaxies. Although the field strengths we compute are
probably adequate as seed fields for a galactic dynamo, the field is too small
to have had significant effects on galaxy formation, on thermal conduction, or
on cosmic ray transport in the intergalactic medium. It could, however, be
observed in the intergalactic medium through innovative methods based on
analysis of gamma-ray burst photon arrival times.Comment: accepted for publication in ApJ. MPEG movies and color versions of
figures are available at
http://casa.colorado.edu/~gnedin/GALLERY/magfi_p.htm
On Supergroups with Odd Clifford Parameters and Supersymmetry with Modified Leibniz Rule
We investigate supergroups with Grassmann parameters replaced by odd Clifford
parameters. The connection with non-anticommutative supersymmetry is discussed.
A Berezin-like calculus for odd Clifford variables is introduced. Fermionic
covariant derivatives for supergroups with odd Clifford variables are derived.
Applications to supersymmetric quantum mechanics are made. Deformations of the
original supersymmetric theories are encountered when the fermionic covariant
derivatives do not obey the graded Leibniz property. The simplest non-trivial
example is given by the N=2 SQM with a real multiplet and a cubic
potential. The action is real. Depending on the overall sign ("Euclidean" or
"Lorentzian") of the deformation, a Bender-Boettcher pseudo-hermitian
hamiltonian is encountered when solving the equation of motion of the auxiliary
field. A possible connection of our framework with the Drinfeld twist
deformation of supersymmetry is pointed out.Comment: Final version to be published in Int. J. Mod. Phys. A; 20 page
Renormalizability of N=1/2 Wess-Zumino model in superspace
In this letter we use the spurion field approach adopted in hep-th/0307099 in
order to show that by adding F and F^2 terms to the original lagrangian, the
N=1/2 Wess-Zumino model is renormalizable to all orders in perturbation theory.
We reformulate in superspace language the proof given in the recent work
hep-th/0307165 in terms of component fields.Comment: 8 pages, minor change
Non-Perturbative Green's Functions in Theories with Extended Superconformal Symmetry
The multiplets that occur in four dimensional rigidly supersymmetric theories
can be described either by chiral superfields in Minkowski superspace or
analytic superfields in harmonic superspace. The superconformal Ward identities
for Green's functions of gauge invariant operators of these types are derived.
It is shown that there are no chiral superconformal invariants. It is further
shown that the Green's functions of analytic operators are severely restricted
by the superconformal Ward when analyticity is taken into account.Comment: 17 pages, plain tex. Some conjectures that were in the original paper
are clarifed in the light of more recent work to which we give references.
See Note added for detail
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