782 research outputs found
Characterization and functional roles of paternal RNAs in 2–4 cell bovine embryos
Embryos utilize oocyte-donated RNAs until they become capable of producing RNAs through embryonic genome activation (EGA). The sperm\u2019s influence over pre-EGA RNA content of embryos remains unknown. Recent studies have revealed that sperm donate non-genomic components upon fertilization. Thus, sperm may also contribute to RNA presence in pre-EGA embryos. The first objective of this study was to investigate whether male fertility status is associated with the RNAs present in the bovine embryo prior to EGA. A total of 65 RNAs were found to be differentially expressed between 2\u20134 cell bovine embryos derived from high and low fertility sires. Expression patterns were confirmed for protein phosphatase 1 regulatory subunit 36 (PPP1R36) and ataxin 2 like (ATXN2L) in three new biological replicates. The knockdown of ATXN2L led to a 22.9% increase in blastocyst development. The second objective of this study was to characterize the parental origin of RNAs present in pre-EGA embryos. Results revealed 472 sperm-derived RNAs, 2575 oocyte-derived RNAs, 2675 RNAs derived from both sperm and oocytes, and 663 embryo-exclusive RNAs. This study uncovers an association of male fertility with developmentally impactful RNAs in 2\u20134 cell embryos. This study also provides an initial characterization of paternally-contributed RNAs to pre-EGA embryos. Furthermore, a subset of 2\u20134 cell embryo-specific RNAs was identified
On the Rigorous Derivation of the 3D Cubic Nonlinear Schr\"odinger Equation with A Quadratic Trap
We consider the dynamics of the 3D N-body Schr\"{o}dinger equation in the
presence of a quadratic trap. We assume the pair interaction potential is
N^{3{\beta}-1}V(N^{{\beta}}x). We justify the mean-field approximation and
offer a rigorous derivation of the 3D cubic NLS with a quadratic trap. We
establish the space-time bound conjectured by Klainerman and Machedon [30] for
{\beta} in (0,2/7] by adapting and simplifying an argument in Chen and
Pavlovi\'c [7] which solves the problem for {\beta} in (0,1/4) in the absence
of a trap.Comment: Revised according to the referee report. Accepted to appear in
Archive for Rational Mechanics and Analysi
Second-order corrections to mean field evolution for weakly interacting Bosons. I
Inspired by the works of Rodnianski and Schlein and Wu, we derive a new
nonlinear Schr\"odinger equation that describes a second-order correction to
the usual tensor product (mean-field) approximation for the Hamiltonian
evolution of a many-particle system in Bose-Einstein condensation. We show that
our new equation, if it has solutions with appropriate smoothness and decay
properties, implies a new Fock space estimate. We also show that for an
interaction potential , where is
sufficiently small and , our program can be easily
implemented locally in time. We leave global in time issues, more singular
potentials and sophisticated estimates for a subsequent part (part II) of this
paper
Inhomogeneous chiral symmetry breaking in noncommutative four fermion interactions
The generalization of the Gross-Neveu model for noncommutative 3+1 space-time
has been analyzed. We find indications that the chiral symmetry breaking occurs
for an inhomogeneous background as in the LOFF phase in condensed matter.Comment: 17 pages, 2 figures, published version, minor correction
Two-Step Model of Fusion for Synthesis of Superheavy Elements
A new model is proposed for fusion mechanisms of massive nuclear systems
where so-called fusion hindrance exists. The model describes two-body collision
processes in an approaching phase and shape evolutions of an amalgamated system
into the compound nucleus formation. It is applied to Ca-induced
reactions and is found to reproduce the experimental fusion cross sections
extremely well, without any free parameter. Combined with the statistical decay
theory, residue cross sections for the superheavy elements can be readily
calculated. Examples are given.Comment: 4 pages, 4 figure
Relativistic instant-form approach to the structure of two-body composite systems
A new approach to the electroweak properties of two-particle composite
systems is developed. The approach is based on the use of the instant form of
relativistic Hamiltonian dynamics. The main novel feature of this approach is
the new method of construction of the matrix element of the electroweak current
operator. The electroweak current matrix element satisfies the relativistic
covariance conditions and in the case of the electromagnetic current also the
conservation law automatically. The properties of the system as well as the
approximations are formulated in terms of form factors. The approach makes it
possible to formulate relativistic impulse approximation in such a way that the
Lorentz-covariance of the current is ensured. In the electromagnetic case the
current conservation law is ensured, too. The results of the calculations are
unambiguous: they do not depend on the choice of the coordinate frame and on
the choice of "good" components of the current as it takes place in the
standard form of light--front dynamics. Our approach gives good results for the
pion electromagnetic form factor in the whole range of momentum transfers
available for experiments at present time, as well as for lepton decay constant
of pion.Comment: 26 pages, Revtex, 5 figure
Scalar Solitons on the Fuzzy Sphere
We study scalar solitons on the fuzzy sphere at arbitrary radius and
noncommutativity. We prove that no solitons exist if the radius is below a
certain value. Solitons do exist for radii above a critical value which depends
on the noncommutativity parameter. We construct a family of soliton solutions
which are stable and which converge to solitons on the Moyal plane in an
appropriate limit. These solutions are rotationally symmetric about an axis and
have no allowed deformations. Solitons that describe multiple lumps on the
fuzzy sphere can also be constructed but they are not stable.Comment: 24 pages, 2 figures, typo corrected and stylistic changes. v3:
reference adde
Preparation of decoherence-free, subradiant states in a cavity
The cause of decoherence in a quantum system can be traced back to the
interaction with the environment. As it has been pointed out first by Dicke, in
a system of N two-level atoms where each of the atoms is individually dipole
coupled to the environment, there are collective, subradiant states, that have
no dipole coupling to photon modes, and therefore they are expected to decay
slower. This property also implies that these type of states, which form an N-1
dimensional subspace of the atomic subsytem, also decohere slower. We propose a
scheme which will create such states. First the two-level atoms are placed in a
strongly detuned cavity and one of the atoms, called the control atom is
excited. The time evolution of the coupled atom-cavity system leads to an
appropriately entangled state of the atoms. By applying subsequent laser pulses
at a well defined time instant, it is possible to drive the atomic state into
the subradiant, i. e., decoherence free subspace. Up to a certain average
number of the photons, the result is independent of the state of the cavity.
The analysis of the conditions shows that this scheme is feasible with present
day techniques achieved in atom cavity interaction experiments.Comment: 5 page
Magnetism in a lattice of spinor Bose condensates
We study the ground state magnetic properties of ferromagnetic spinor
Bose-Einstein condensates confined in a deep optical lattices. In the Mott
insulator regime, the ``mini-condensates'' at each lattice site behave as
mesoscopic spin magnets that can interact with neighboring sites through both
the static magnetic dipolar interaction and the light-induced dipolar
interaction. We show that such an array of spin magnets can undergo a
ferromagnetic or anti-ferromagnetic phase transition under the magnetic dipolar
interaction depending on the dimension of the confining optical lattice. The
ground-state spin configurations and related magnetic properties are
investigated in detail
Magnetic catalysis and anisotropic confinement in QCD
The expressions for dynamical masses of quarks in the chiral limit in QCD in
a strong magnetic field are obtained. A low energy effective action for the
corresponding Nambu-Goldstone bosons is derived and the values of their decay
constants as well as the velocities are calculated. The existence of a
threshold value of the number of colors , dividing the theories with
essentially different dynamics, is established. For the number of colors , an anisotropic dynamics of confinement with the confinement
scale much less than and a rich spectrum of light glueballs is
realized. For of order or larger, a conventional confinement
dynamics takes place. It is found that the threshold value grows
rapidly with the magnetic field [ for ]. In contrast to QCD with a nonzero baryon density, there are no
principal obstacles for checking these results and predictions in lattice
computer simulations.Comment: 10 pages, 1 figure. REVTeX. Minor correction. To appear in Phys. Rev.
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