Genetic gain in perennial ryegrass (Lolium perenne) varieties 1973 to 2013

AbstractPerennial ryegrass (Lolium perenne) forms the basis of grassland production in temperate pastures and is globally one of the most important forage grasses. Consequently, there has been large plant breeding industry investment over the past 40 years in producing new varieties and independent testing systems designed to identify and list those with the most improved performances. This study was conducted at the Plant Testing Station, Crossnacreevy, Northern Ireland and compared the DM yield and sward density of new varieties submitted from 1973 to 2013 and grass digestibility from 1980 to 2013, under conservation and simulated grazing managements. A variety × years matrix was compiled for each parameter and comparable means between varieties never in side by side performance trials were produced. Dry matter yields showed an overall significant (p &lt; 0.001) average annual increase of 0.52 % under conservation and 0.35 % under simulated grazing, with similar gain levels within maturity groups or ploidies. These rates were not constant over time, and periods of no gain occurred in various variety groupings. Sward density of the examined varieties did not change significantly. Herbage digestibility showed no improvement over the timeframe but had the largest differences between concurrent varieties, indicating that improvements were possible in the future. The study indicated that plant breeding gains were primarily DM yield focused with sward density remaining stagnant over the 40 years, while the lack of grass digestibility improvement appeared to only require more time to overcome. Evidence of benefits and risks of variety testing influences on plant breeding objectives was discussed.</jats:p

Detection of transit timing variations in excess of one hour in the Kepler multi-planet candidate system KOI 806 with the GTC

We report the detection of transit timing variations (TTVs) well in excess of one hour in the Kepler multi-planet candidate system KOI 806. This system exhibits transits consistent with three separate planets -- a Super-Earth, a Jupiter, and a Saturn -- lying very nearly in a 1:2:5 resonance, respectively. We used the Kepler public data archive and observations with the Gran Telescopio de Canarias to compile the necessary photometry. For the largest candidate planet (KOI 806.02) in this system, we detected a large transit timing variation of -103.5$\pm$6.9 minutes against previously published ephemeris. We did not obtain a strong detection of a transit color signature consistent with a planet-sized object; however, we did not detect a color difference in transit depth, either. The large TTV is consistent with theoretical predictions that exoplanets in resonance can produce large transit timing variations, particularly if the orbits are eccentric. The presence of large TTVs among the bodies in this systems indicates that KOI806 is very likely to be a planetary system. This is supported by the lack of a strong color dependence in the transit depth, which would suggest a blended eclipsing binary.Comment: 9 pages, 4 figures, accepted into A&A Letter

Helping patients discuss CINV management : development of a patient charter

In April 2012, an Expert Group of specialist cancer nurses working in a variety of settings (e.g. chemotherapy delivery, chemotherapy service design, research, nurse leadership and patient information/advocacy) participated in telephone/web-based meetings, with the aim of sharing current experience of chemotherapy-induced nausea and vomiting (CINV) management, and reaching a consensus on the development of a Patient Charter, designed to help patients understand CINV management, and setting out key questions they may wish to ask their healthcare professionals

What makes good feedback good?

HE institutions persistently seek to increase student engagement and satisfaction with assessment feedback, but with limited success. This study identifies the attributes of good feedback from the perspective of recipients. In a distinctive participatory research design, student participants were invited to bring along actual examples of feedback that they perceived as either ‘good’ or ‘bad’ to 32 interviews with student researchers. Findings highlight the complex interdependency and contextual nature of key influences on students’ perspectives. The feedback artefact itself, its place in assessment and feedback design, relationships of the learner with peers and tutors, and students’ assessment literacy all affect students’ perspectives. We conclude that standardising the technical aspects of feedback, such as the feedback artefact or the timing or medium of its delivery is insufficient: a broader consideration of all key domains of influence is needed to genuinely increase student engagement and satisfaction with feedback

Comparing Drying Protocols for Perennial Ryegrass Samples in Preparation for Chemical Analysis

Diet formulation for animals requires accurate estimation of feed nutritive value. In order to determine the nutritive value of grass, the moisture in the samples must be removed, with minimum damage to cell structure, and then the dried samples milled, prior to chemical analysis. Generally samples are oven dried. The aim of this study was to verify if differing drying protocols gave diverging results when drying grass samples. The drying protocols investigated were 40°C for 48 hours, 60°C for 48 hours and 95°C for 15 hours in forced convection ovens. Four perennial ryegrass samples were cut to 4 cm from ground level on three occasions in 2012. On each occasion the four grass samples were mixed together thoroughly and divided into four replicates. Each replicate was divided into three sub-samples to give one 100 g-sample per drying treatment. At regular intervals the samples were removed from the oven and the weight recorded. The data were analysed using a mixed model repeated measures procedure in SAS. Time (hours) was used as the repeated measure. A separate dataset of 12 grass samples were dried using both the 40°C and 60°C protocols and then chemically analysed. This dataset was analysed using PROC GLM in SAS. Samples were assumed dry when there was no significant difference in weight between times. All drying protocols gave a similar final dry matter of approximately 156 g/kg. All drying protocols did dry the grass samples adequately as samples dried at 40°C and 60°C were not significantly lighter after 24 hours and samples dried at 95°C were not significantly lighter after 15 hours. There were no differences in ash or crude protein concentration of the samples dried using the 40°C and 60°C protocols. There were differences in the organic matter digestibility, neutral detergent fibre and acid detergent fibre concentrations between the grass samples dried using the different drying protocols

Immediate and Carryover Effects of Post-Grazing Sward Height Imposed in Early Spring on Sward and Milk Production

A grazing experiment was undertaken to investigate the immediate and carryover effect of post-grazing sward height (PGH) in early spring on sward and dairy cow production. Ninety Holstein-Friesian spring calving dairy cows were randomly assigned across 3 PGH treatments: 2.7, 3.5 and 4.2 cm from February 14 to April 24, 2011. Following the experimental period animals were managed similarly until the end of the lactation. Grazing to 2.7 cm during the experimental period reduced milk (-159 kg/cow; P \u3c 0.01) and milk solids (-16 kg/cow; P \u3c 0.01) yields and increased BW loss (+13 kg loss; P \u3c 0.05) when compared to the 3.5 and 4.2 cm treatments which performed similarly. Grass utilisation (\u3e2.7 cm) increased (P \u3c 0.001) by decreasing PGH from 4.2 cm (0.74) to 3.5 cm (0.82) and further to 2.7 cm (0.94). During the carryover period (April 24 to November 13), cumulative milk (3542 kg/cow) and milk solids (281 kg/cow) yields did not differ between the experimental treatments. End BW was similar across treatments (503 kg). Total lactation performance of cows grazing to 2.7 cm in spring was -24 kg milk solids (P \u3c 0.05) than the total lactation production of the 3.5 and 4.2 cm treatments (405 kg milk solids) indicating that cows offered a restricted pasture allowance in early lactation do not recover lost production. This study recommends a PGH of 3.5 cm in the first 2 grazing rotations to achieve a compromise between sward utilisation and animal performance in early spring while also ensuring high subsequent lactation milk production

Short-Term Milk Yield Response to Changes in Post-Grazing Sward Height

In temperate climates, grazed grass is the cheapest source of nutrients for the dairy cow (Finneran et al. 2010), therefore its utilisation should be optimised throughout the grazing season to increase enterprise profitability (Shalloo et al. 2004). Within spring-calving systems, energy requirements increase for the post-parturient dairy cow during the spring period. On the other hand, spring grass supply can be limited given low over-winter grass growth rates. The imposition of a lower post-grazing sward height (PGH) during this critical time may be a viable solution to increase grass availability. As the season progresses, PGH may be increased or decreased to adjust the allowance of grass in the dairy cow’s diet depending on farm grass supply. Quantifying the variation in animal production with changes in PGH will inform such decisions. Currently, there is no information available on the milk production response to changes in PGH over a short period of the lactation. Therefore, the aim of this experiment was to determine the short-term variation in milk yield (MY) and yields of protein, fat and lactose in response to changes in PGH around the tenth week of lactation of the spring calving dairy cow

Fermi-Liquid Interactions in d-Wave Superconductor

This article develops a quantitative quasiparticle model of the low-temperature properties of d-wave superconductors which incorporates both Fermi-liquid effects and band-structure effects. The Fermi-liquid interaction effects are found to be classifiable into strong and negligible renormalizaton effects, for symmetric and antisymmetric combinations of the energies of $k\uparrow$ and $-k\downarrow$ quasiparticles, respectively. A particularly important conclusion is that the leading clean-limit temperature-dependent correction to the superfluid density is not renormalized by Fermi-liquid interactions, but is subject to a Fermi velocity (or mass) renormalization effect. This leads to difficulties in accounting for the penetration depth measurements with physically acceptable parameters, and hence reopens the question of the quantitative validity of the quasiparticle picture.Comment: 4 page