Shape predicates allow unbounded verification of linearizability using canonical abstraction

Canonical abstraction is a static analysis technique that represents states as 3-valued logical structures, and is able to construct finite representations of systems with infinite statespaces for verification. The granularity of the abstraction can be altered by the definition of instrumentation predicates, which derive their meaning from other predicates. We introduce shape predicates for preserving certain structures of the state during abstraction. We show that shape predicates allow linearizability to be verified for concurrent data structures using canonical abstraction alone, and use the approach to verify a stack and two queue algorithms. This contrasts with previous efforts to verify linearizability with canonical abstraction, which have had to employ other techniques as well

Analysing Scientific Collaborations of New Zealand Institutions using Scopus Bibliometric Data

Scientific collaborations are among the main enablers of development in small national science systems. Although analysing scientific collaborations is a well-established subject in scientometrics, evaluations of scientific collaborations within a country remain speculative with studies based on a limited number of fields or using data too inadequate to be representative of collaborations at a national level. This study represents a unique view on the collaborative aspect of scientific activities in New Zealand. We perform a quantitative study based on all Scopus publications in all subjects for more than 1500 New Zealand institutions over a period of 6 years to generate an extensive mapping of scientific collaboration at a national level. The comparative results reveal the level of collaboration between New Zealand institutions and business enterprises, government institutions, higher education providers, and private not for profit organisations in 2010-2015. Constructing a collaboration network of institutions, we observe a power-law distribution indicating that a small number of New Zealand institutions account for a large proportion of national collaborations. Network centrality concepts are deployed to identify the most central institutions of the country in terms of collaboration. We also provide comparative results on 15 universities and Crown research institutes based on 27 subject classifications.Comment: 10 pages, 15 figures, accepted author copy with link to research data, Analysing Scientific Collaborations of New Zealand Institutions using Scopus Bibliometric Data. In Proceedings of ACSW 2018: Australasian Computer Science Week 2018, January 29-February 2, 2018, Brisbane, QLD, Australi

The use of mid-infrared spectrometry to predict body energy status of Holstein cows

Energy balance, especially in early lactation, is known to be associated with subsequent health and fertility in dairy cows. However, its inclusion in routine management decisions or breeding programs is hindered by the lack of quick, easy, and inexpensive measures of energy balance. The objective of this study was to evaluate the potential of mid-infrared (MIR) analysis of milk, routinely available from all milk samples taken as part of large-scale milk recording and milk payment operations, to predict body energy status and related traits in lactating dairy cows. The body energy status traits investigated included energy balance and body energy content. The related traits of body condition score and energy intake were also considered. Measurements on these traits along with milk MIR spectral data were available on 17 different test days from 268 cows (418 lactations) and were used to develop the prediction equations using partial least squares regression. Predictions were externally validated on different independent subsets of the data and the results averaged. The average accuracy of predicting body energy status from MIR spectral data was as high as 75% when energy balance was measured across lactation. These predictions of body energy status were considerably more accurate than predictions obtained from the sometimes proposed fat-to-protein ratio in milk. It is not known whether the prediction generated from MIR data are a better reflection of the true (unknown) energy status than the actual energy status measures used in this study. However, results indicate that the approach described may be a viable method of predicting individual cow energy status for a large scale of application

Lameness affects cow feeding but not rumination behaviour as characterised from sensor data

Using automatic sensor data, this is the first study to characterize individual cow feeding and rumination behavior simultaneously as affected by lameness. A group of mixedparity, lactating Holstein cows were loose-housed with free access to 24 cubicles and 12 automatic feed stations. Cows were milked three times/day. Fresh feed was delivered once daily. During 24 days with effectively 22 days of data, 13,908 feed station visits and 7,697 rumination events obtained from neck-mounted accelerometers on 16 cows were analyzed. During the same period, cows were locomotion scored on four occasions and categorized as lame (n = 9) or not lame (n = 7) throughout the study. Rumination time, number of rumination events, feeding time, feeding frequency, feeding rate, feed intake, and milk yield were calculated per day, and coefficients of variation were used to estimate variation between and within cows. Based on daily sums, using each characteristic as response, the effects of lameness and stage of lactation were tested in a mixed model. With rumination time as response, each of the four feeding characteristics, milk yield, and lameness were tested in a second mixed model. On a visit basis, effects of feeding duration, lameness, and milk yield on feed intake were tested in a third mixed model. Overall, intra-individual variation was <15% and inter-individual variation was up to 50%. Lameness introduced more inter-individual variation in feeding characteristics (26–50%) compared to non-lame cows (17–29%). Lameness decreased daily feeding time and daily feeding frequency, but increased daily feeding rate. Interestingly, lameness did not affect daily rumination behaviors, fresh matter intake, or milk yield. On a visit basis, a high feeding rate was associated with a higher feed intake, a relationship that was exacerbated in the lame cows. In conclusion, cows can be characterized in particular by their feeding behavior, and lame cows differ from their non-lame pen-mates in terms of fewer feed station visits, faster eating, less time spent feeding, and more variable feeding behavior. Further, daily rumination time was slightly negatively associated with feeding rate, a relationship which calls for more research to quantify rumination efficiency relative to feeding rate

The effects of feed composition and level on lactational performance in rats and dairy cows: a basic approach to feed description

An investigation into the effects of feed composition on lactational performance was carried out using rats and cows. A graphical representation of the feed as a triangle was used to aid the interpretation of results. The first rat experiment showed that, on high protein feeds, the lactational performance of rats is not depressed when offered feeds of very low carbohydrate content. This was substantiated by the other rat experiments. When carbohydrate in the feed was replaced by fat at low protein content (rat experiment 2) there was a large depression in lactational performance, effectively a cessation of milk production. The interaction between the three feed components protein, carbohydrate, and fat was highly significant. The hypothesis that maternal heat production was limiting food intake was advanced. The third rat experiment used feeds whose composition was marginal in relation to lactational success. The feeds also allowed comparison between feeds of constant nutrient:energy ratio. The results of this experiment indicated that there is an extremely abrupt threshold in feed composition for adequate lactation. This effect could not be attributed to any one nutrient:energy ratio. This experiment also showed the importance of maternal body reserves in support of lactation. A model was developed to explore the hypothesis that maternal heat production was limiting performance, however this model failed. An experiment using sheep was conducted in order to permit prediction of the volatile fatty acid proportions arising from a range of feeds. This experiment was designed to allow application of the rat work to dairy cows. A dairy cow trial was conducted, to compare different feed types and feeding levels. The results of this trial showed no effect of feed type on lactational performance. A linear relationship between food intake and level of milk production was found. This included an effect of feeding level on rate of decline in milk yield. All these findings are discussed in detail

Reduction in daily milk yield associated with sub-clinical bovine herpes virus 1 infection

The aim of this observational cohort study was to investigate the potential economic effect of sub-clinical Bovine Herpes Virus 1 (BoHV-1) infection in a commercial UK dairy herd in terms of milk yield depression. Infection status of cows (infected or not infected) was assigned from serology on a single occasion. A multi-level linear model was used to evaluate the effect of infection status on milk production, using milk records that were routinely collected over two years. BoHV-1 seropositive cows produced 2.6 kg/day less milk over the study period compared with cows that were seronegative. This result highlights the importance of appropriate management of risks associated with BoHV-1 as part of proactive herd health and production management

Digestion, rumen fermentation and circulating concentrations of insulin, growth hormone and IGF-1 in steers fed diets based on different proportions of maize silage and grass silage

Replacing grass silage with maize silage results in a fundamental change in the ratio of structural to non-structural carbohydrates with commensurate changes in rumen fermentation patterns and nutrient utilisation. This study investigated the effects of feeding four forage mixtures, namely grass silage (G); 67 g/100 g grass silage133 g/100 g maize silage (GGM); 67 g/100 g maize silage133/100 g grass silage (MMG); maize silage (M) to four ruminally and duodenally canulated Holstein Friesian steers. All diets were formulated to be isonitrogenous (22.4 g N/kg DM) using a concentrate mixture. Dietary dry matter (DM) and organic matter (OM) digestibility increased with ascending maize silage inclusion (P,0.1) whereas starch and neutral detergent fibre digestibility declined (P,0.05). Ratio of non-glucogenic to glucogenic precursors in the rumen fluid increased with maize silage inclusion (P,0.01) with a commensurate reduction in rumen pH (P,0.05). Mean circulating concentrations of insulin were greatest and similar in diets MMG and GGM, lower in diet M and lowest in diet G (P,0.01). There were no effects of diet on the mean circulating concentration of growth hormone (GH), or the frequency, amplitude and duration of GH pulses, or the mean circulating concentrations of IGF-1. Increasing levels of DM, OM and starch intakes with the substitution of grass silage with maize silage affected overall digestion, nutrient partitioning and subsequent circulating concentrations of insulin

Webs of influence: Investigating the effects of the forest mycorrhizosphere on soil carbon storage in a changing world

Anthropogenic climate change is broadly accepted to be the biggest threat to ecosystems in the 21st century, with the most rapid change occurring in Arctic regions. It is necessary to understand the consequences of on-going warming, such as changing vegetation and northward advance of Arctic treelines, as well as examining the robustness of proposed mitigation strategies, such as intensified tree planting. Using field based approaches in soil carbon rich sub-Arctic and high latitude boreal regions, I found that Betula pubescens roots and associated mycorrhizal fungi extend 3-4.5 m away from trees, thereby covering open forest gaps, possibly creating a ‘wood-wide-web’. However, I found no evidence of common mycelial networks between trees or the understorey in these forests. My findings indicate consistent high production of roots and mycorrhizas throughout the forest floor, coupled with declining soil organic carbon (SOC) stocks with increasing distance from trees. In the Scottish uplands, with comparable tree and understorey species, I found that planting B. pubescens onto heather moorland leads to a 58 and 50% loss of SOC stocks 12 and 39 years after planting, resulting in no net gain in ecosystem C. Long term tree planting experiments provide empirical evidence for the consequences of tree planting schemes as a climate change mitigation strategy and the potential effects of warming-driven encroachment of Arctic treeline forests onto globally important ericaceous soil carbon stores. Combined, my results show how B. pubescens mycorrhizospheres - their roots and associated mycorrhizas - effectively explore throughout the forest floor and shape the spatial dynamics and depletion of soil carbon stocks in Arctic and boreal regions most vulnerable to climate change. Furthermore, this work suggests that, although urgent action on climate change is needed, awareness of the ecological context is crucial if planting trees is to be a robust strategy for climate change mitigation