Feed efficiency indexes and their relationships with carcass, non-carcass and meat quality traits in Nellore steers.

Five hundred and seventy-five Nellore steers were evaluated for residual feed intake and residual feed intake and gain and their relationships between carcass, non-carcass and meat quality traits. RFI was measured by the difference between observed and predicted dry matter intake and RIG was obtained by the sum of -1*RFI and residual gain. Efficient and inefficient animals were classified adopting ±0.5 standard deviations from RFI and RIG mean. A mixed model was used including RFI or RIG and contemporary group as fixed effects, initial age as covariate and sire and experimental period as random effects, testing the significance of the regression slope for each evaluated trait. RIG was positively related to longissimus muscle area. Efficient-RFI animals had lower liver and internal fat proportions compared to inefficient-RFI animals. Efficient-RFI and efficient-RIG animals had 11.8% and 11.2% lower extracted intramuscular fat, compared to inefficient-RFI and inefficient-RIG animals, respectively. Efficient-RFI animals had tougher meat compared to inefficient-RFI animals.

Ductus venosus Doppler velocimetry in the first trimester: a new finding.

OBJECTIVES: To establish reference curves for ductus venosus blood flow velocities during the first trimester and compare them with previously published curves. METHODS: This was a cross-sectional and retrospective study performed between January 1998 and January 2003. The following inclusion criteria were used: singleton pregnancy, velocity measurements taken when the crown-rump length (CRL) was between 34 and 84 mm, absence of fetal anomalies, full-term pregnancy and newborn birth weight appropriate for gestational age. The following variables of the ductus venosus were measured: peak velocity during ventricular systole (S-wave) and diastole (D-wave), nadir during atrial contraction in late diastole (A-wave), time-averaged maximum velocity (TAMXV) and pulsatility index for veins (PIV). RESULTS: A total of 843 fetuses were included. The mean CRL was 62 (range, 34-84) mm. The S-wave, D-wave, TAMXV and PIV were normally distributed, and logarithmic transformation was performed to achieve a normal distribution for the A-wave. S-wave, D-wave and A-wave and TAMXV increased with CRL. PIV increased up to a CRL of 63 mm and decreased thereafter. Regression analysis revealed a significant quadratic relationship between PIV and CRL. CONCLUSIONS: S-wave, D-wave, A-wave velocities and TAMXV in the ductus venosus increase with CRL between 34 and 84 mm. The reference range for PIV has a biphasic pattern, with an initial non-significant increase up to a CRL of 63 mm and a fall thereafter.

Discrete atomistic model to simulate etching of a crystalline solid.

A discrete atomistic solid-on-solid model is proposed to describe dissolution of a crystalline solid by a liquid. The model is based on the simple assumption that the probability per unit time of a unit cell being removed is proportional to its exposed area. Numerical simulations in one dimension demonstrate that the model has very good scaling properties. After removal of only about 10(2) monolayers, independently of the substrate size, the etched surface shows almost time-independent short-range correlations and the receding surface presents the Family-Vicsek scaling behavior. The scaling parameters alpha=0.491+/-0.002 and beta=0.330+/-0.001 indicate that the system belongs to the Kardar-Parisi-Zhang universality class. The imposition of periodic boundary conditions on the simulations reduces the effective system size by a factor of 0.68 without changing the exponents alpha and beta. Surprisingly, the periodic condition changes drastically the statistics of the surface height fluctuations and the short-range correlations. Without periodic conditions, that statistics is, up to 3 standard deviations, an asymmetric Lévy distribution with mu=1.82+/-0.01, and outside this region the statistics is Gaussian. With periodic conditions, that statistics is Gaussian, except for large negative fluctuations.