145 research outputs found
The impact of fetal gender on prematurity in dichorionic twin gestations after in vitro fertilization
<p>Abstract</p> <p>Background</p> <p>Impact of fetal gender on prematurity has been primarily investigated in singleton pregnancies. In an attempt to understand better how fetal gender may affect gestational length in twin gestations after in vitro fertilization, same-sex twins and opposite twins were compared for pregnancy duration.</p> <p>Methods</p> <p>This study evaluated 113 women at ages 20 to 39 years with consecutive dichorionic-diamniotic twin gestations after assisted reproduction. All pregnancies were results of fresh in vitro fertilization (IVF) cycles with use of autologous oocytes and sperm and were delivered at up to 37 weeks of gestation at a University-based high-risk, maternal-fetal medicine unit.</p> <p>Results</p> <p>Both groups did not differ in baseline characteristics, such as maternal ages, indications for fertility treatments, number of previous IVF attempts, body mass index and parity. Opposite sex- twins, however, presented with significantly shorter gestational age at birth (32.9 +/- 3.4 weeks) than same-sex twins (34.3 +/- 2.5 weeks), (p < 0.05). Younger maternal age was also associated with shorter pregnancy duration (p < 0.05).</p> <p>Conclusions</p> <p>Fetal gender mix serves as risk factor for more significant prematurity in dichorionic-diamniotic twins after assisted reproduction with opposite sex twins at higher risk than same sex-twins.</p
Does the 2D Hubbard Model Really Show d-Wave Superconductivity?
Some issues concerning the question if the two-dimensional Hubbard model
really show d-wave superconductivity are briefly discussed.Comment: Revtex, no figure
Enhancement of the d_{x^2-y^2} pairing correlation in the two-dimensional Hubbard model: a quantum Monte Carlo study
Quantum Monte Carlo is used to investigate the possibility of d_{x^2-y^2}
superconductivity in the two-dimensional repulsive Hubbard model. A small
energy scale relevant to possible pairing requires a care (i.e., sufficiently
small level separation between the points and
with small 's) to detect enhanced
correlations in finite-size studies, as motivated from a previous study on
Hubbard ladders. Our calculation indeed detects long-tailed enhancements in the
d_{x^2-y^2} pairing correlation when the system is near, but not exactly at,
half-filling.Comment: 4 pages, RevTeX, uses epsf.sty and multicol.st
Quantum Monte Carlo Evidence for d-wave Pairing in the 2D Hubbard Model at a van Hove Singularity
We implement a Quantum Monte Carlo calculation for a repulsive Hubbard model
with nearest and next-nearest neighbor hopping interactions on clusters up to
12x12. A parameter region where the Fermi level lies close to the van Hove
singularity at the Saddle Points in the bulk band structure is investigated. A
pairing tendency in the symmetry channel, but no other channel,
is found. Estimates of the effective pairing interaction show that it is close
to the value required for a 40 K superconductor. Finite-size scaling compares
with the attractive Hubbard model.Comment: 11 pages, REVTex, 4 figures, postscrip
Ground state of the three-band Hubbard model
The ground state of the two-dimensional three-band Hubbard model in oxide
superconductors is investigated by using the variational Monte Carlo method.
The Gutzwiller-projected BCS and spin- density wave (SDW) functions are
employed in the search for a possible ground state with respect to dependences
on electron density. Antiferromagnetic correlations are considerably enhanced
near half-filling. It is shown that the d-wave state may exist away from
half-filling for both the hole and electron doping cases. The overall structure
of the phase diagram obtained by the calculations qualitatively agrees with
experimental indications. The superconducting condensation energy is in
reasonable agreement with the experimental value obtained from specific heat
and critical magnetic field measurements for optimally doped samples. The
inhomogeneous SDW state is also examined near 1/8-hole doping.Comment: 10 pages, 17 figure
Tocolysis for inhibiting preterm birth in extremely preterm birth, multiple gestations and in growth-restricted fetuses: a systematic review and meta-analysis
The prognostic value of plasma fibrinogen levels in patients with endometrial cancer: a multi-centre trial
Can prematurity risk in twin pregnancies after in vitro fertilization be predicted? A retrospective study
Enhanced epithelial to mesenchymal transition (EMT) and upregulated MYC in ectopic lesions contribute independently to endometriosis
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