1,667 research outputs found
Sign of CP Violating Phase in Quarks and Leptons
We discuss the relation between the CP violation of the quark mixing and that
of the lepton mixing by investigating a CP violating observable, the Jarlskog
invariant, as well as the CP violating Dirac phase. The down-type quark mass
matrix with three zeros is given in terms of the minimal number of parameters,
while the up-type quark mass matrix is diagonal. These quark mass matrices
leading to the successful CKM mixing angles and CP violation are embedded in
both the Pati--Salam and SU(5) models. The leptonic Jarlskog invariant
(as well as CP violating Dirac phase) is examined for two cases: the
neutrino mass matrix is diagonal or non-diagonal, where no additional CP
violating phase is introduced apart from the Majorana phases. In the case of
the diagonal neutrino mass matrix, the favorable sign of the leptonic CP
violation is obtained, however, the magnitude of is at most , which is too small compared with the expected value from the
observation . In the case of the non-diagonal neutrino mass matrix where
the tri-bimaximal mixing pattern is taken, we obtain the successful
up to its sign.Comment: 25 pages, 4 tables, some references are added(v.2), minor
revisions(v.3
Perovskite solar cells with CuI inorganic hole conductor
An organic material, 2,2\u27,7,7\u27-tetrakis(N,N-di-p-methoxyphenylamine)9,9\u27-spirobifluorene (spiro-OMeTAD), is generally used as a hole conductor of perovskite solar cells (PSCs), but spiro-OMeTAD is much more expensive than other materials used in PSCs. In this study, we have prepared PSCs with a cost-effective CuI hole transport layer by spin coating. The merit of using spin coating for CuI is good compatibility with other steps, such as spin coating of a TiO2 electron transport layer and a perovskite active layer. The CuI-based PSC recorded power conversion efficiencies of η = 2.22% (max) on the day of production and η = 6.52% (max) after the 20 days of production. Moreover, the CuI-based PSC had a smaller hysteresis than the spiro-based PSC, suggesting that CuI is a highly promising alternative hole conductor for PSCs
Bilinear Gaussian Belief Propagation for Massive MIMO Detection with Non-Orthogonal Pilots
Ito K., Takahashi T., Ibi S., et al. Bilinear Gaussian Belief Propagation for Massive MIMO Detection with Non-Orthogonal Pilots. IEEE Transactions on Communications , (2023); https://doi.org/10.1109/TCOMM.2023.3325479.We propose a novel joint channel and data estimation (JCDE) algorithm via bilinear Gaussian belief propagation (BiGaBP) for massive multi-user MIMO (MU-MIMO) systems with non-orthogonal pilot sequences. The contribution aims to reduce significantly the communication overhead required for channel acquisition by enabling the use of short non-orthogonal pilots, while maintaining multi-user detection (MUD) capability. Bilinear generalized approximate message passing (BiGAMP), which is systematically derived by extending approximate message passing (AMP) to the bilinear inference problem (BIP), provides computationally efficient approximate implementations of large-scale JCDE via sum-product algorithm (SPA); however, as the pilot length decreases, the estimation accuracy is severely degraded. To tackle this issue, the proposed BiGaBP algorithm generalizes BiGAMP by relaxing its dependence on the large-system limit approximation and leveraging the belief propagation (BP) concept. In addition, a novel belief scaling method complying with the data detection accuracy for each iteration step is designed to avoid the divergence behavior of iterative estimation in the early iterations due to the use of non-orthogonal pilots, especially in insufficient large-system conditions. Simulation results show that the proposed method outperforms the state-of-the-art schemes and approaches the performance of idealized (genie-aided) scheme in terms of mean square error (MSE) and bit error rate (BER) performances
Time-series photometry of Earth flyby asteroid 2012 DA14
Context. The object 2012 DA14 is a near-Earth asteroid with a size of several
tens of meters. It had approached closely the Earth on 15 February, 2013 UT,
providing an opportunity for precise measurements of this tiny asteroid. Aims.
The solar phase angle of 2012 DA14 had varied widely around its closest
approach but was almost constant during the following night. We performed
time-series photometric observations on those two nights to determine the
rotational properties and phase effect. Methods. The observations were carried
out using the 0.55-m telescope at Saitama University, Japan. The R-band images
were obtained continuously over a 2 hr period at the closest approach and for
about 5 hr on the next night. Results. The lightcurve data from the second
night indicates a rotational period of 11.0 +1.8/-0.6 hr and a peak-to-peak
amplitude of 1.59 +/- 0.02 mag. The brightness variation before and after the
closest approach was separated into two components that are derived from the
rotation and phase effect. We found that the phase curve slope of this asteroid
is significantly shallower than those of other L-type asteroids. Conclusions.
We suggest that 2012 DA14 is coated with a coarse surface that lacks fine
regolith particles and/or a high albedo surface.Comment: 4 pages, 4 figures, accepted for publication in Astronomy and
Astrophysic
GONAD: Genome-editing via Oviductal Nucleic Acids Delivery system: a novel microinjection independent genome engineering method in mice.
Microinjection is considered the gold standard technique for delivery of nucleic acids (NAs; transgenes or genome editing tools such as CRISPR/Cas9 systems) into embryos, for creating genetically modified organisms. It requires sophisticated equipment as well as well-trained and highly skilled personnel to perform the micro-injection technique. Here, we describe a novel and simple microinjection-independent technique, called Genome-editing via Oviductal Nucleic Acids Delivery (GONAD). Using GONAD, we show that NAs (e.g., eGFP mRNA or Cas9 mRNA/sgRNAs) can be effectively delivered to pre-implantation embryos within the intact mouse oviduct by a simple electroporation method, and result in the desired genetic modification in the embryos. Thus GONAD can bypass many complex steps in transgenic technology such as isolation of zygotes, microinjection of NAs into them, and their subsequent transfer to pseudo-pregnant animals. Furthermore, this method can potentially be used for genome editing in species other than mice
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