180 research outputs found
Supernova Constraints on Models of Neutrino Dark Energy
In this paper we use the recently released Type Ia Supernova (SNIa) data to
constrain the interactions between the neutrinos and the dark energy scalar
fields. In the analysis we take the dark energy scalars to be either
Quintessence-like or Phantom-like. Our results show the data mildly favor a
model where the neutrinos couple to a phantom-like dark energy scalar, which
implies the equation of state of the coupled system behaves like Quintom
scenario in the sense of parameter degeneracy. We find future observations like
SNAP are potentially promising to measure the couplings between neutrino and
dark energy.Comment: Typos fixed and references updated. Version pressed in PR
Minimizing the number of matchings of fixed size in a -saturated graph
For a fixed graph , a graph is said to be -saturated if does
not contain a subgraph isomorphic to but does contain after the
addition of any new edge.
Let be a matching consisting of edges and be the join
graph of a complete graph and an empty graph . In
this paper, we prove that for and , contains the
minimum number of among all -vertex -saturated graphs for
sufficiently large , and when , it is the unique extremal graph.
In addition, we also show that is the unique extremal graph when
and .Comment: 10 page
CRISPR/Cas9-mediated gene manipulation to create single-amino-acid-substituted and floxed mice with a cloning-free method.
Clustered regulatory interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) technology is a powerful tool to manipulate the genome with extraordinary simplicity and speed. To generate genetically modified animals, CRISPR/Cas9-mediated genome editing is typically accomplished by microinjection of a mixture of Cas9 DNA/mRNA and single-guide RNA (sgRNA) into zygotes. However, sgRNAs used for this approach require manipulation via molecular cloning as well as in vitro transcription. Beyond these complexities, most mutants obtained with this traditional approach are genetically mosaic, yielding several types of cells with different genetic mutations. Recently, a growing body of studies has utilized commercially available Cas9 protein together with sgRNA and a targeting construct to introduce desired mutations. Here, we report a cloning-free method to target the mouse genome by pronuclear injection of a commercial Cas9 protein:crRNA:tracrRNA:single-strand oligodeoxynucleotide (ssODN) complex into mouse zygotes. As illustration of this method, we report the successful generation of global gene-knockout, single-amino-acid-substituted, as well as floxed mice that can be used for conditional gene-targeting. These models were produced with high efficiency to generate non-mosaic mutant mice with a high germline transmission rate
Two-loop gluino contributions to neutron electric dipole moment in CP violating MSSM
We analyze two-loop gluino corrections to the neutron electric dipole moment
(EDM) in the minimal supersymmetry extension of the standard model (MSSM). The
dependence of two-loop corrections on the relevant CP violating phases differs
from that of the one-loop contributions, and there is a region in the parameter
space where the two-loop contributions are comparable with the one-loop
contributions. Our numerical results show that the two-loop corrections can be
as large as 30% of the one-loop results.Comment: Revtex, 27 pages, including 11 ps figure
- …