11 research outputs found
Atom--Molecule Coherence in a Bose-Einstein Condensate
Coherent coupling between atoms and molecules in a Bose-Einstein condensate
(BEC) has been observed. Oscillations between atomic and molecular states were
excited by sudden changes in the magnetic field near a Feshbach resonance and
persisted for many periods of the oscillation. The oscillation frequency was
measured over a large range of magnetic fields and is in excellent quantitative
agreement with the energy difference between the colliding atom threshold
energy and the energy of the bound molecular state. This agreement indicates
that we have created a quantum superposition of atoms and diatomic molecules,
which are chemically different species.Comment: 7 pages, 6 figure
The effect of extended post-mortem ageing on the Warner–Brazler shear force of longissimus thoracis from beef heifers from two sire breeds, slaughtered at 20 or 25 mo of age
peer-reviewedwere examined. Spring-born Angus × Holstein-Friesian heifers (n = 48) and Belgian Blue ×
Holstein-Friesian heifers (n = 48) were slaughtered, within sire breed, at 20 or 25 mo of age. Approximately 48 h
post-mortem, LT steaks (2.5 cm) were removed, and either stored at −20°C for chemical analysis or vacuum-packed,
stored at 2°C for 7, 14 or 28 d post-mortem and then at −20°C pending Warner–Bratzler shear force (WBSF) analysis.
Muscle from Angus-sired heifers had higher (P < 0.001) intramuscular fat (IMF) concentration, lower (P < 0.001)
proportion of type IIX muscle fibres and higher (P < 0.001) proportion of type IIA and type I muscle fibres compared to
muscle from Belgian Blue-sired heifers. Collagen characteristics did not differ between sire breeds. Later slaughter
increased (P < 0.001) IMF concentration and decreased (P < 0.001) total and insoluble concentrations and collagen
solubility. There were no interactions between the main effects for WBSF and no difference between sire breeds.
Later slaughter and increasing the duration of ageing decreased (P < 0.05) WBSF. Based on threshold WBSF values
in the literature, all samples would be considered tender (<39 N) after 7 d ageing. Untrained consumers are likely
to detect the decrease in WBSF from 7 to 14 d ageing but not due to further ageing. Within the production system
examined and based on WBSF data, extending LT ageing to 28 d is not necessary to ensure consumer satisfaction