9,090 research outputs found
Finite-Element Simulations of Light Propagation through Circular Subwavelength Apertures
Light transmission through circular subwavelength apertures in metallic films
with surrounding nanostructures is investigated numerically. Numerical results
are obtained with a frequency-domain finite-element method. Convergence of the
obtained observables to very low levels of numerical error is demonstrated.
Very good agreement to experimental results from the literature is reached, and
the utility of the method is demonstrated in the investigation of the influence
of geometrical parameters on enhanced transmission through the apertures
Fast simulation method for parameter reconstruction in optical metrology
A method for automatic computation of parameter derivatives of numerically
computed light scattering signals is demonstrated. The finite-element based
method is validated in a numerical convergence study, and it is applied to
investigate the sensitivity of a scatterometric setup with respect to
geometrical parameters of the scattering target. The method can significantly
improve numerical performance of design optimization, parameter reconstruction,
sensitivity analysis, and other applications
Three-dimensional quasi-Tonks gas in a harmonic trap
We analyze the macroscopic dynamics of a Bose gas in a harmonic trap with a
superimposed two-dimensional optical lattice, assuming a weak coupling between
different lattice sites. We consider the situation in which the local chemical
potential at each lattice site can be considered as that provided by the
Lieb-Liniger solution. Due to the weak coupling between sites and the form of
the chemical potential, the three-dimensional ground-state density profile and
the excitation spectrum acquire remarkable properties different from both 1D
and 3D gases. We call this system a quasi-Tonks gas. We discuss the range of
applicability of this regime, as well as realistic experimental situations
where it can be observed.Comment: 4 pages, 3 figures, misprints correcte
Filter cassette for high volume air sampler
Filter cassette eliminates or substantially reduces contamination of filter media by extraneous material and facilitates handling
Multidimensional solitons in periodic potentials
The existence of stable solitons in two- and three-dimensional (2D and 3D)
media governed by the self-focusing cubic nonlinear Schr\"{o}dinger equation
with a periodic potential is demonstrated by means of the variational
approximation (VA) and in direct simulations. The potential stabilizes the
solitons against collapse. Direct physical realizations are a Bose-Einstein
condensate (BEC) trapped in an optical lattice, and a light beam in a bulk Kerr
medium of a photonic-crystal type. In the 2D case, the creation of the soliton
in a weak lattice potential is possible if the norm of the field (number of
atoms in BEC, or optical power in the Kerr medium) exceeds a threshold value
(which is smaller than the critical norm leading to collapse). Both
"single-cell" and "multi-cell" solitons are found, which occupy, respectively,
one or several cells of the periodic potential, depending on the soliton's
norm. Solitons of the former type and their stability are well predicted by VA.
Stable 2D vortex solitons are found too.Comment: 13 pages, 3 figures, Europhys. Lett., in pres
No increase in pregnancy rate of mares after preovulatory deep uterine horn application of misoprostol.
A potential source of fertility loss in mares is oviductal dysfunction, potentially caused by masses or debris in the lumen, that may prevent either sperm from reaching the fertilization site or the embryo from reaching the uterus. Recently a novel therapeutic method leading to increased pregnancy results was described by infusing misoprostol, a synthetic prostaglandin E1, in the uterus of mares with unexplained fertility problems. In this study, we aimed, after examining the compatibility of misoprostol with semen, to evaluate the pregnancy rate after routine preovulatory deep uterine horn application of misoprostol in clinically normal oestrous mares, which were inseminated in the same cycle. In experiment 1, ejaculates of 10 stallions diluted with INRA 96™ were mixed with different concentrations of misoprostol (0.01 mg/mL, 0.001 mg/mL, 0.0001 mg/mL, and 0.00001 mg/mL) and total semen motility was evaluated immediately, 12, 24, 48, and 72 h later, and compared with a control sample (mixed with NaCl 0.9%). In experiments 2 and 3, 33 privately-owned clinically normal oestrous mares were each allocated to a treatment or control group. Ovulation was then induced with intramuscularly 2.25 mg deslorelin acetate. At the moment of ovulation induction (experiment 2) and 24 h earlier (experiment 3), 0.2 mg misoprostol diluted in 2 mL NaCl 0.9% were applied deep in the uterine horn (treatment groups) and pure 2 mL NaCl 0.9% in the mares of the control groups. Mares were then inseminated 24 h after deslorelin administration and prior to ovulation with commercial chilled-warmed or frozen-thawed semen, as well as immediately after ovulation detection (both types of semen) maximally 48 h after ovulation induction. In experiment 1, regardless of time and compared with the control groups, all solutions with different concentrations of misoprostol had a negative effect on total motility of semen, which was significant for the highest concentrations (0.01 mg/mL: 18.0% reduction, CI = 22-13%, p = < 0.01). We found no beneficial effect of preovulatory uterine treatment with misoprostol on pregnancy rate (OR = 0.45, CI = 0.15-1.31, p = 0.14): in experiment 2, 2/11 (18.2%) mares of the treatment group became pregnant vs. 12/22 (54.5%) mares in the control group (OR = 0.19, CI = 0.03-1.06, p = 0.07), in experiment 3, 5/14 (35.7%) mares in the treatment group vs. 7/19 (36.8%) mares in the control group (OR = 0.95, CI = 0.23-4.02, p = 0.95), respectively. In conclusion, pregnancy rate was not increased in reproductively normal mares with routine preovulatory deep uterine horn application of misoprostol
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