GrassGroTM simulation of pasture, animal performance and greenhouse emissions on low and high sheep productivity grazing systems: 1-year validation and 25-year analysis.

Globally, there is a focus on reducing the absolute methane (CH4) and nitrous oxide emissions, and the emissions intensity (EI, kg CO2e/kg animal product) of livestock production. Increasing the productivity of mixed pasture systems has the potential to increase food (e.g., lamb) and textile fibre (e.g., wool) production while reducing the EI of those products from grazing livestock. The objective of this study was to quantify the differences in greenhouse gas (GHG) emissions and EI between sheep on Low (i.e., low sustainable stocking rate) and High (i.e., high sustainable stocking rate) productivity grazing systems (PGSs). Therefore, a replicated breeding-ewe trial on 18 paddocks was established across 2 - years. Three flocks on Low (3 × 16 ewes/flock) and High PGSs (3 × 32 ewes/flock) rotated across three land-classes and three paddocks per PGS. In year 1, the observed on-farm pasture quantity, quality, and botanical composition, together with lamb BW (kg), and daily CH4 production (DMP, g CH4/head per day) using Open Path Fourier Transformed Infrared (OP-FTIR) spectrometers data were measured. Subsequently, two simulations using GrassGroTM were conducted: (1) a 1-year GrassGroTM simulation that used the observed on-farm data to adjust parameters: date of mating, paddock fertility, and weight of mature ewes to validate GrassGroTM predictions to achieve accuracy and precision targets; and (2) a 25-year (1986-2011) simulation to analyse the effects of Low and High PGSs on sheep production and GHG emissions across a variable climate. The 1-year validation predictions fitted well with the observed on-farm data for: pasture biomass (kg/ha), DM digestibility (%), botanical composition (kg/ha), lamb (kg) product, and DMP (g CH4/head per day). The subsequent predicted results from the 25-year GrassGroTM simulation showed minimal effect of PGS on the mean DM intake (kg DM/day) or DMP for Low and High PGSs, but this was thought to be due to the biomass in both PGSs exceeding 1 500 kg DM/ha. The EI, over the 25-year simulation, on the High PGS was 16.5% lower than the Low PGS. Additional calculations of DMP were conducted using a recent global equation, giving estimates of DMP that closely matched the observed on-farm OP-FTIR DMP measurements, but these were lower than the GrassGroTM predictions and improved the accuracy and precision. It is concluded that in some pasture situations, managing pastures and stock numbers to intensify grazing systems can allow increased livestock production, without increasing daily CH4 emissions/head while substantially decreasing the EI of the animal products generated.

Perioperative administration of tranexamic acid in hip fracture surgery (The PATHS study): national audit of current practice.

INTRODUCTION: Neck of femur fractures (NOFF) are associated with significant morbidity and mortality, exacerbated by anaemia. Evidence indicates tranexamic acid (TXA) administration in NOFF surgery reduces blood loss and transfusion requirements, without increasing complications. The aim of this study was to establish current TXA administration practice in patients undergoing surgery for NOFF in the UK. METHODS: We conducted a multicentre prospective study within the UK over a two-week period in March 2019. Pre-, intra- and postoperative data were collected locally and analysed centrally. RESULTS: Data for 917 patients were submitted from 66 institutions. Of those eligible, 48.0% received TXA perioperatively. Administration rates varied from 0 to 100%. Significantly greater numbers undergoing arthroplasty received TXA (57.6%) compared with internal fixation (38.4%, p<0.01). Some 15.2% of institutions had a protocol for TXA use in NOFF. Patients treated in these units were significantly more likely to receive TXA (86.7%) than those who were not (41.2% p<0.01). Of those receiving TXA, 92.3% were given 1g intravenously (IV) at anaesthetic administration. CONCLUSIONS: Despite supportive evidence for its use, a wide variation in the administration of TXA between hospitals and procedures has been demonstrated. Administration rates were higher for arthroplasty than for fixation procedures. Most centres do not have a protocol guiding TXA administration. We recommend administration of 1g IV TXA perioperatively for patients undergoing NOFF surgery, where not contraindicated, unless future randomised controlled trials support an alternative regimen. We recommend units include their own locally agreed TXA policy within a written protocol for the care of NOFF patients.

Field measurement of beef pen manure methane and nitrous oxide reveals a surprise for inventory calculations.

Few data exist on direct greenhouse gas emissions from pen manure at beef feedlots. However, emission inventories attempt to account for these emissions. This study used a large chamber to isolate NO and CH emissions from pen manure at two Australian commercial beef feedlots (stocking densities, 13-27 m head) and related these emissions to a range of potential emission control factors, including masses and concentrations of volatile solids, NO, total N, NH, and organic C (OC), and additional factors such as total manure mass, cattle numbers, manure pack depth and density, temperature, and moisture content. Mean measured pen NO emissions were 0.428 kg ha d (95% confidence interval [CI], 0.252-0.691) and 0.00405 kg ha d (95% CI, 0.00114-0.0110) for the northern and southern feedlots, respectively. Mean measured CH emission was 0.236 kg ha d (95% CI, 0.163-0.332) for the northern feedlot and 3.93 kg ha d (95% CI, 2.58-5.81) for the southern feedlot. Nitrous oxide emission increased with density, pH, temperature, and manure mass, whereas negative relationships were evident with moisture and OC. Strong relationships were not evident between NO emission and masses or concentrations of NO or total N in the manure. This is significant because many standard inventory calculation protocols predict NO emissions using the mass of N excreted by the animal.

Predicting the human in vivo performance of different oral capsule shell types using a novel in vitro dynamic gastric model.

The disintegration of a capsule shell may determine the onset of drug dissolution from capsule formulations. In this study, the release of a rapidly dissolving model drug (paracetamol), from two hydroxypropyl methylcellulose capsules containing either carageenan (HPMC-C) or gellan gum (HPMC-G) and one hard gelatin (HG) capsule, were investigated using a conventional in vitro model, the USP dissolution apparatus I, and a novel in vitro model of the human gastric compartment, the dynamic gastric model (DGM). The results obtained in vitro were compared with in vivo gamma scintigraphy human data and in vivo gastric emptying profiles available in the literature. The drug release from HPMC-G capsules, observed with the USP dissolution apparatus I, was delayed with respect to the other two capsules, while the results obtained from the DGM in the fasted state were closer together, which was in agreement with data from the in vivo studies. In the fasted state, the capsule rupture times obtained from the DGM were similar to those observed by gamma scintigraphy in vivo studies. In the fed state, the 'apparent' rupture times observed with the DGM were delayed compared to fasted, and were even longer than those observed by scintigraphy in vivo for HPMC-G and HG capsules. However, these discrepancies can reasonably be explained by considering the impact of food upon dispersion of the capsule contents and the sampling from the DGM, when compared to the human scintigraphy experiments.

Coarse particulate matter emissions from cattle feedlots in Australia.

Open cattle feedlots are a source of air pollutants that include particular matter (PM). Over 24 h, exposure to ambient concentrations of 50 microg m(-3) of the coarse-sized fraction PM (aerodynamic diameter <10 microm [PM(10)]) is recognized as a health concern for humans. The objective of our study was to document PM(10) concentration and emissions at two cattle feedlots in Australia over several days in summer. Two automated samplers were used to monitor the background and in-feedlot PM(10) concentrations. At the in-feedlot location, the PM(10) emission was calculated using a dispersion model. Our measurements revealed that the 24-h PM(10) concentrations on some of the days approached or exceeded the health criteria threshold of 50 microg m(-3) used in Australia. A key factor responsible for the generation of PM(10) was the increased activity of cattle in the evening that coincided with peak concentrations of PM(10) (maximum, 792 microg m(-3)) between 1930 and 2000 h. Rain coincided with a severe decline in PM(10) concentration and emission. A dispersion model used in our study estimated the emission of PM(10) between 31 and 60 g animal(-1) d(-1). These data contribute to needed information on PM(10) associated with livestock to develop results-based environmental policy.

A gamma-ray burst at a redshift of z approximately 8.2.

Long-duration gamma-ray bursts (GRBs) are thought to result from the explosions of certain massive stars, and some are bright enough that they should be observable out to redshifts of z > 20 using current technology. Hitherto, the highest redshift measured for any object was z = 6.96, for a Lyman-alpha emitting galaxy. Here we report that GRB 090423 lies at a redshift of z approximately 8.2, implying that massive stars were being produced and dying as GRBs approximately 630 Myr after the Big Bang. The burst also pinpoints the location of its host galaxy.

Finding extraterrestrial sites for thermophiles.

Virtually our entire knowledge of the universe comes from two sorts of measurement of the electromagnetic radiation from the stars and galaxies within it; either their flux through relatively wide bandpasses (photometry), or measurements of the shape and wavelength of relatively narrow lines via spectroscopy. These techniques are now being used to discover planets outside our solar system, and perhaps in the next 10 years will begin to characterize them. If a serious search is to be made for extraterrestrial thermophiles, we need predictions for the effects of thermophiles on their host planets that are observable with these techniques. In this paper I shall outline what sorts of observation are likely to be used in the next 15 years for extra-solar planet work. All of the journal articles quoted here can be found through http://adsabs.harvard.edu/abstract_service.html, and often also accessed as preprints at http://uk.arxiv.org/form/astro%20ph?MULTI=form%20+/-%20interface.