The effect of cereal type and feeding frequency on intake, rumen fermentation, digestibility, growth and carcass traits of finishing steers offered a grass silage-based diet

peer-reviewedThe effect of concentrate cereal type (rolled barley-based v. rolled wheat-based) and concentrate feeding frequency (one 6 kg feed v. two 3 kg feeds per day) on intake, rumen fermentation, diet digestibility and performance of finishing steers offered grass silage to appetite was evaluated over four experiments using a total of 154 animals. Not all four feeding treatments were used in each of the four experiments. The duration of the growth measurement period was 152, 112, 111 and 113 days for experiments 1 to 4, respectively, after which all animals were slaughtered. Dietary dry matter (DM) intake and in vivo digestibility, final live weight, kill-out proportion, carcass weight, carcass conformation score, carcass fat score and daily liveweight and estimated carcass gain were not affected (P > 0.05) by cereal type or feeding frequency. Cereal type or feeding frequency had no effect (P > 0.05) on feed conversion efficiency (FCE) expressed as either live-weight or carcass gain per unit DM intake. Neither mean rumen fluid pH or concentrations of ammonia or L-lactate were influenced by cereal type or feeding frequency. The mean molar proportion of propionate was higher and that of butyrate lower (P < 0.05) with wheat than with barley. Estimated carcass weight gain and FCE to carcass were similar for wheat based and barley-based concentrate as a supplement to grass silage offered either as one feed or two equal feeds daily

Non-equilibrium dynamics in the dual-wavelength operation of Vertical external-cavity surface-emitting lasers

Microscopic many-body theory coupled to Maxwell's equation is used to investigate dual-wavelength operation in vertical external-cavity surface-emitting lasers. The intrinsically dynamic nature of coexisting emission wavelengths in semiconductor lasers is associated with characteristic non-equilibrium carrier dynamics which causes significant deformations of the quasi-equilibrium gain and carrier inversion. Extended numerical simulations are employed to efficiently investigate the parameter space to identify the regime for two-wavelength operation. Using a frequency selective intracavity etalon, two families of modes are stabilized with dynamical interchange of the strongest emission peaks. For this operation mode, anti-correlated intensity noise is observed in agreement with the experiment. A method using effective frequency selective filtering is suggested for stabilization genuine dual-wavelength output.Comment: 15 pages, 7 figure

BUIILDING SKINS AS KINETIC PROCESS: SOME PRECEDENT FROM THE FINE ARTS

The aesthetics of form in motion has been a central preoccupation for the visual arts of the twentieth century, culminating in the establishment of kinetic art as a distinct area of activity in the 1950's. Architecture has traditionally resisted ‘building kinetics’, but has embraced the body in motion, usually on foot negotiating in (subtle) interaction with static form. However, one aspect in which kinetics would appear to be acceptable is at the building periphery, where intelligent facades track sun angles, or moderate air movement in response to internal temperature sensors. On another track is the proliferation of media facades in various guises that transform facades into urban information interfaces or media art works. This paper suggests that both intelligent and media facades set a different agenda for designers who have traditionally worked towards finding the best static mix of performance and elegance. Arguably, intelligent and media facades raises the question of ontology from a designer perspective - what are the design parameters when the outcome is a kinetic system, rather than the traditional static artifact? In order to approach the issue, this paper examines some precedent from kinetic art of the 1960’s and contemporary generative arts, for the insight they may provide. These sources then inform a preliminary outline of the range of parameters that may be considered by designers

Optimising The Response To Supplementary Concentrates By Beef Cattle In Winter

End of project reportConcentrates are a major component of feed costs in winter finishing of beef cattle. Two separate experiments were carried out to evaluate the response to increasing supplementary concentrate level with grass silage and the effects of feeding the silage and concentrates separately or as a total mixed ration (TMR). In experiment 1, a total of 117 finishing steers (initial live weight 538 kg, s.d. 35.5) were assigned to a preexperimental slaughter group of 9 animals and to 6 feeding treatments of 18 animals each. The feeding treatments were: 1) silage (SO) only offered ad libitum, 2) SO plus a low level of concentrates offered separately (LS), 3) SO plus a low level of concentrates offered as a TMR (LM), 4) SO plus a medium level of concentrates offered separately (MS), 5) SO plus a medium level of concentrates offered as a TMR (MM), and 6) concentrates ad libitum plus a restricted silage allowance (AL). Low and medium target concentrate levels were 3 and 6 kg dry matter (DM) per head daily. When silage and concentrates were fed separately, the daily concentrate allowance was given in one morning feed. The animals were individually fed for a mean period of 132 days. After slaughter, carcasses were weighed and graded and the ribs joint was dissected into its component tissues. Silage DM intake decreased but total DM intake increased with increasing concentrate level. Live weight gains for SO, LS, LM, MS, MM and AL were 0.34, 0.86, 0.86, 1.02, 1.00 and 1.12 (s.e. 0.064) kg/day, respectively. Corresponding carcass weight gains were 0.25, 0.58, 0.58, 0.71, 0.68 and 0.82 (s.e. 0.028) kg/day. All measures of fatness increased, ribs joint bone proportion decreased, and muscle proportion was not significantly affected by dietary concentrate level. There were no significant interactions between concentrate level and method of feeding. Compared with offering the feeds separately, feeding a TMR increased silage DM intake by proportionately 0.06 and total DM intake by proportionately 0.04. Otherwise, method of feeding had no significant effect on performance, slaughter or carcass traits. Mean rumen pH decreased while ammonia concentration tended to increase with increasing concentrate level. Total volatile fatty acids and the acetate to propionate ratio were lowest for SO. Method of feeding had no significant effect on rumen fermentation

A note on the effect of post-mortem maturation on colour of bovine Longissimus dorsi muscle

peer-reviewedFinancial support to P.G. Dunne was provided under the Walsh Fellowship programme of Teagasc.Fifteen heifers were housed and fed a concentrate diet while 54 counterparts grazed at pasture for 90 days at which stage six heifers from each group were slaughtered. The remaining animals in the pasture group were then housed and offered either: concentrate only; concentrate plus grass silage with silage accounting for either 20% or 50% of the total dry matter offered; or zero-grazed grass plus concentrate with grass accounting for 83% of the dry matter offered. Heifers (3/diet) were slaughtered 28, 56, 91 and 120 days thereafter. Colour characteristics of M. longissimus dorsi (LD) were measured at 48 h post mortem. The LD was then vacuum-packaged and stored at between 0 and 4 °C in darkness for 12 days, when colour characteristics were again measured. Maturation of LD resulted in meat that had higher redness values (‘a’ value; P<0.001) and a more intense red colour (higher ‘C’ value; P<0.001) at 14 days post mortem than at 2 days, regardless of diet/duration of feeding. Maturation also resulted in a brighter colour (higher ‘L’ value; P<0.001) but this difference was greatest when cattle were slaughtered the day-56 time point

Mode-locking in vertical external-cavity surface-emitting lasers with type-II quantum-well configurations

A microscopic study of mode-locked pulse generation is presented for vertical external-cavity surface-emitting lasers utilizing type-II quantum well configurations. The coupled Maxwell semiconductor Bloch equations are solved numerically where the type-II carrier replenishment is modeled via suitably chosen reservoirs. Conditions for stable mode-locked pulses are identified allowing for pulses in the \unit[100]{fs} range. Design strategies for type-II configurations are proposed that avoid potentially unstable pulse dynamics.Comment: Main paper with supplementary material

Visualisation and auralisation of architectural design in a game engine based collaborative virtual environment

This paper describes the development of collaborative virtual environment (CVE) software based on a game engine to support the early stages of design in the context of architectural education. The precedent of narrative drawing technique in architecture is introduced. From this we position the use of a CVE as a means to explore design context in a manner that is not possible when using typical architectural visualization software. Outcomes from software trials are reported that establish the value of working in a real time environment where design iterations can be tested from multiple points of view, and the important role of 3D sound to evoke occupancy and materiality. Negative results are reported in relation to collaborative design functionality and a revised approach based on an integrated project database is described