bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal Timescale Mass Transfer in Binary Population Synthesis
Authors: Justham Stephen , Kolb Ulrich
Published: June 2019

Studies of binary evolution have, until recently, neglected thermal timescale mass transfer (TTMT). Recent work has suggested that this previously poorly studied area is crucial in the understanding of systems across the compact binary spectrum. We use the state-of-the-art binary population synthesis code BiSEPS (Willems and Kolb, 2002, MNRAS 337 1004-1016). However, the present treatment of TTMT is incomplete due to the nonlinear behaviour of stars in their departure from gravothermal ‘equilibrium’. Here we show work that should update the ultrafast stellar evolution algorithms within BiSEPS to make it the first pseudo-analytic code that can follow TTMT properly. We have generated fits to a set of over 300 Case B TTMT sequences with a range of intermediate-mass donors. These fits produce very good first approximations to both HR diagrams and mass-transfer rates (see figures 1 and 2), which we later hope to improve and extend. They are already a significant improvement over the previous fits.
XMM-Newton and Optical Observations of WZ Sagittae in Quiescence
Authors: Mukai K. , Patterson J.
Published: June 2019

WZ Sge- is the prototype of a subclass of dwarf novae with an extremely long recurrence period. In addition, it exhibits rapid oscillations at 27.87 s and 28.96 s. We present our preliminary analysis of XMM-Newton and optical observations taken in 2003 May, almost 2 years after the 2001 outburst.
A Reformulation of Divine's Interplanetary Model
Authors: Matney M. J. , Kessler D. J.
Published: June 2019

Divine (1993) developed a mathematical model to use measurements of interplanetary dust to determine the orbital distributions of particles in interplanetary space. The power of the model is that it uses the fact that the dust particles are in Keplerian orbits to correct for the observation biases based on spatial density and velocity efifects of the orbits. In order to do this, he creates families of dust orbits; within each of which the particles have mathematically separable distributions of mass, periapsis, eccentricity, and inclination. He then uses a trial-and-error method to vary these distributions until an adequate fit is made to the data. Each of his distributions is loosely based on populations of interplanetary dust that are believed to be present in the Solar System.
When Might 2P/Encke Have Produced Meteor Storms?
Authors: Steel D.I. , Asher D.J.
Published: June 2019

2P/Encke is the only Earth-crossing short-period comet to have a meteoroid/dust trail identified in the data collected by IRAS Such trails have been suggested by Kresák to be the cause of meteor storms, these occurring when the comet/trail node is near 1 AU and the Earth happens to pass through the trail. Here we present the results of integrations of variational orbits of 2P/Encke (the differences in the assumed initial semi-major axes representing the order of changes that could occur due to non-gravitational effects) from which we derive indications of when this comet may have produced meteor storms in the past. Pairs of sets of storms are expected about 300 yr apart, but the effects of chaotic dynamical evolution (and our ignorance of 2P/Encke's non-gravitational forces for any but the last two centuries) mean that we cannot define the epochs in which these may have occurred to better than 200 BC to AD 500 for the last pair, and 3600 to 1800 BC for the previous pair. Looking forwards in time, no meteor storm due to 2P/Encke will occur for at least 600 yr.
Estimating the Asteroidal Component of the Zodiacal Cloud using the Earth's Resonant Ring
Authors: Jayaraman Sumita , Dermott Stanley F.
Published: June 2019

The Earth's resonant ring is populated primarily by asteroidal dust particles because cometary particles have higher Poynting-Robertson drag rates and the Earth's resonances are not strong enough to trap them (Gomes, 1995). It has been shown that asteroidal particles in a limited size range from 5 — 30μm are responsible for the observed trailing/leading flux asymmetry caused by the trailing dust cloud embedded in the ring (Jayaraman and Dermott 1995). The magnitude of the flux asymmetry is a direct function of the area of dust in the ring, which in turn depends upon the number of asteroidal particles in the zodiacal cloud. Using a dynamical model of the ring and the background zodiacal cloud and estimating the surface area of dust needed in the ring to match the observed flux asymmetry in the 25 micron COBE waveband, we have calculated the fraction of asteroidal dust in the zodiacal cloud as a function of p, the slope of the size-frequency distribution of particles.
SIRTF: A Unique Opportunity for Probing the Zodiacal Cloud
Authors: Jayaraman Sumita , Dermott Stanley F. , Werner Michael
Published: June 2019

The Space Infrared Telescope Facility (SIRTF) is planned for launch by NASA in 2001 in a heliocentric orbit at 1.01 AU The spacecraft will drift away from the Earth slowly, reaching a distance of 0.3 AU behind the Earth at the end of its 2.5 year mission. This implies that SIRTF will spiral through the Earth's resonant dust ring (Wright et al., 1995) and, in particular, that it will traverse the dust cloud in the ring that trails the Earth in its orbit. We have used a dynamical model of the ring (Dermott et al., 1994) followed by simulation of the SIRTF orbit to predict the variations in the zodiacal thermal emission due to the trailing dust cloud as seen by SIRTF. Because the dust ring is inclined to the ecliptic, the latitude of peak flux of the trailing cloud will have yearly oscillations about the ecliptic. The amplitude of the oscillations will increase as SIRTF approaches the cloud, reaching a maximum of 20 during the mission. The magnitude of the flux variations can be as high as 4 – 5% or 2–3 MJy/Sr, SIRTF's measurements of these effects will allow us to model the number density and thermal characteristics of asteroidal dust particles near the Earth.
Orbital Evolution of Small Particles Ejected from Martian Satellites
Authors: Ishimoto Hiroshi
Published: June 2019

The dynamical behavior of dust particles ejected from Martian satellites is examined. On the basis of numerical simulations and analytical estimation for the orbital evolution of particles, we have found that there exists two kinds of resonance orbits around Mars. Particles ejected from Phobos and Deimos are influenced by these orbital resonances, and form dust rings with an asymmetrical structure along the orbit of the satellite, i.e., dust rings with a thin disk-like shape for Phobos and with a vertically extended structure for Deimos.
Archiving Impact Data: The LDEF IDE Database
Authors: Paul K. G.
Published: June 2019

After the retrieval of the NASA Long Duration Exposure Facility (LDEF), postflight investigations started on the Interplanetary Dust Experiment (IDE). The time- and orientation resolved dataset was processed at the Institute for Space Science and Technology (ISST) in Gainesville, FL, residue chemistry analyses were conducted at the Analytical Instrumentation Facility at North Carolina State University (NCSU-AIF), Raleigh, NC, and system-level tests were performed at NASA Langley Research Center (LaRC) in Hampton, VA, among other investigators. With the end of the postflight investigation program it was considered compulsory to archive all data in a format that would facilitate future analyses.
Hypervelocity Capture of Meteoroids in Aerogel
Authors: Tsou P.
Published: June 2019

Micrometeoroids of cometary or asteroidal origin constitute a unique repository of information concerning the formation and subsequent processing history of materials in the solar nebula. One of the current goals of planetary science is to return samples from a known primitive extraterrestrial body for detailed laboratory analysis (NASA Solar System Exploration Committee, SSEC 1983). Planetary flyby orbital motions dictate that dust particles will approach the spacecraft at relative speeds up to tens of km/s. It has always been thought that these hypervelocity particles could not be captured without melting or vaporizing. We have developed the intact capture technology that enables flyby sample return of these hypervelocity particles. The STARDUST comet sample return mission, selected as the fourth NASA. Discovery mission, capitalizes on this technology (Brownlee et al. 1996).
An Optical Instrument to Characterize Individual Dust Particles
Authors: Giovane Frank , Gustafson Bo Å. S. , Lamy Philippe L.
Published: June 2019

The conceptual design for an optical instrument capable of characterizing dust particles by in situ measurements is described. This instrument, the Integrated Dust Analyzer (IDA), measures the light scattered at several different angles as a particle passes through a pair of polarized light curtains. It is capable of defining or providing an indication of such characteristics as size, index of refraction, absorptivity, and aggregate structure.
Optical and Thermal Properties of Zodiacal Dust
Authors: Levasseur-Regourd A.C.
Published: June 2019

Recent progress has been reported in the determination of the zodiacal thermal emission, brightness and polarization. These results, of interest to estimate the foreground sources in astrophysical observations, do not provide immediately information on the dust distribution, and on its optical and thermal properties. To infer local information about the bulk density, and the physical properties of the dust particles, it is necessary to compare the observations with realistic models or to invert the line-of-sight data. The latter approach typically suggests that the bulk density is (in the symmetry plane) inversely proportional to the solar distance, that the particles are not spheroidal, but rather irregular in shape, that their physical properties change with their distance to the Sun and their orbital inclination, and finally that they do not emit like a blackbody. The heterogeneity noticed in the cloud is due to various sources of dust particles, the size, shape or albedo of which evolve as a function of time, under collision and/or evaporation processes.
On the Dielectric Function of Partially Amorphous Olivine Dust
Authors: Lynch David K. , Mazuk S.
Published: June 2019

We present a new technique for computing the optical constants for partially disordered solids based on their crystalline optical constants. The technique assumes that the material is composed of a continuous distribution of oscillators (CDO) and that the degree of atomic disorder can be described by one, or at most two, scalar parameters. We apply the technique to an oft-mentioned solar system material, olivine, and show that its dielectric functions can be predicted for an arbitrary degree of disorder.
Sublimation of Interplanetary Dust
Authors: Mukai Tadashi
Published: June 2019

Three topics are briefly reviewed to examine evidence for the nature of dust grains and grain alteration by physical processes related to mainly sublimation. Namely, (1) a change of dust flux detected byin situdust measurements beyond ~ 2 AU from the Sun suggests a disappearance of volatile ices due to sublimation below this distance, (2) an elongation angle dependence of Doppler shifts observed in the zodiacal light can be explained by the introduction of a dependence of the orbital velocity on the radiation pressure forces acting on the grains, taking into account a variation of dust structure with heliocentric distance, and (3) the variation of color temperature observed in cometary coma suggests a loss of carbon content from cometary dust grains due to sublimation. This piece of evidence agrees with the generation of carbon-bearing molecules from extended sources, as infered from observations in cometary comae.
Size Distributions of Asteroidal Dust: Possible Constraints on Impact Strengths
Authors: Durda Daniel D. , Dermott Stanley F.
Published: June 2019

We present results of a numerical collisional model which shows that the slope index of the equilibrium size distribution is dependent upon the size-strength scaling properties of the colliding bodies. This implies that individual asteroid families or distinct taxonomic classes within the mainbelt asteroid population may evolve different equilibrium size distributions. Well constrained observations of the size distribution over particular size ranges may allow constraints to be placed on the impact strengths of particles much larger or smaller than are capable of being measured in laboratory impact experiments.
Chemical Reactions and Dust Destruction in Protoplanetary Accretion Disks
Authors: Finocchi Frédéric , Gail Hans-Peter , Duschl Wolfgang J. , Tscharnuter Werner M.
Published: June 2019

A nonequilibrium calculation for the chemistry in a classical protoplanetary accretion disk is presented. Slow radial particle transport moves grains from the cold outer regions of a protoplanetary accretion disk into its warm central part where grains are destroyed. We consider the destruction processes for the silicate and carbon dust component and follow the chemical composition of the gas as a function of the radial distance from the protostar. The main result of this calculation is the presence of huge amounts of methane at a distance of ~ 1 AU from the protostar as product of the carbon dust destruction. It is very likely that more complex organics also are present' in this region.
Research in language teaching and learning in Austria (2011–2017)
Authors: Dalton-Puffer Christiane , Boeckmann Klaus-Börge , Hinger Barbara
Published: June 2019

This overview of seven years of research on language learning and teaching in Austria reflects a period of steady growth for the language teaching and learning research community, a development due to a national policy agenda aiming for a stronger research base in teacher education. The target languages of the teaching and learning processes investigated are primarily German, English, French, Italian, Spanish as well as several Slavic languages, reflecting the geographical, sociolinguistic and language policy situation of this increasingly multilingual country. This multilingualism means there are clearly many more first languages (L1s) than only German involved in the learning situations investigated. While all the studies reviewed here illustrate research driven by a combination of local and global concerns in connection with different theoretical frameworks, some specific clusters of research interest emerge. These are: societal and individual multilingualism, language education policy, language teacher education, language(s) in other subjects, early language learning, language acquisition and learning, literature and culture, testing and standardisation, digital media, and teaching materials.
Opportunities and possible methods to improve reproduction in the pig
Authors: Johnson Rodger K. , Neal Steven M.
Published: June 2019

Genetic selection for litter size received little attention either by scientists or commercial pig breeders until recently. Low heritability of litter size, its sex-limited expression and the fact that it cannot be measured until reproductive maturity are often given as reasons. But the major reason may be that the reproductive rate of pigs is already quite high, and the economic value of genetic changes in litter size have been small relative to those of efficiency and composition of growth.

The economics of pig production have changed and technological and biological advances have caused us to re-examine the economic value of traits. Reducing fat in the carcass and more efficient conversion of feed to lean meat have always been, and will continue to be, high priority selection objectives for pig breeders. But expensive, environmentally controlled gestation, farrowing and nursery houses are the norm of modern pig production and increasing litter size will result in a significant reduction in the cost of producing lean meat (Tess et al., 1983).
Changes in the producer payments scheme
Authors: Amies S. J.
Published: June 2019

For many years, the Milk Marketing Board (MMB) of England and Wales has operated a pricing system related to the compositional quality of milk supplied by the producer and to the month of supply. As milk production has increased and the seasonal pattern altered, a need has arisen to alter the pricing system.

The volume of milk for manufacture has more than doubled since 1970 and now exceeds that taken by the liquid market. The fat and protein elements of milk are of considerably greater value to the manufacturing market than lactose. To match producer payments more closely to market realities, the MMB will, from April 1984, replace the fat and solids-not-fat compositional quality payment scheme with one based on fat, protein and lactose. The proposed prices at 1983/84 levels are: fat, 2.02; protein, 1.77; and lactose, 0.28 pence/1/10 g/kg.

In the last 10 years, the seasonal trough of production has moved from December to August/September. It is still deepening and adds considerably to marketing costs. In an attempt to slow this trend and also provide a disincentive to additional supplies at peak, the MMB is altering its seasonal price adjustments. Milk prices will be increased in August and September and decreased in May and June.

These changes will not affect the total sum of money available to producers, hence most of them will see little difference to their annual income. The exception will be those producers supplying milk of either especially low or high protein and, to a lesser extent, fat content. The change in seasonal adjustments will, however, cause a noticeable disruption in the cash flow to all producers.
Milk compositional ranges and trends
Authors: Crabtree R. M.
Published: June 2019

The effects of breed, stage of lactation, age and seasonality on the compositional quality of milk are discussed. The Jersey breed has the highest fat and protein contents, 51.9 and 38.5 g/kg milk, respectively, followed by the Guernsey breed, with 46.4 and 36.3 g/kg milk. The British Holstein has the lowest fat and protein contents, at 37.3 and 32.0 g/kg milk, respectively, whilst the Ayrshire is intermediate between the Channel Island and the Friesian and Holstein breeds. The range of fat within a breed may be over 20 g/kg milk. The variation in protein content is less than this value but may be over 10 g/kg milk. Lactose values vary less than those for fat and protein. Mean lactose values are 45.5 g/kg, with a range from 41.0 to 50.0 g/kg milk.

The protein content of milk is high in early lactation, falls rapidly to reach a minimum at approximately 6 weeks after calving, increases slowly to 6 months after calving and then increases rapidly to the end of lactation. The fat content of milk is also high in early lactation and falls to a minimum between the 6th and 10th weeks of lactation. It then rises in a manner similar to protein. Converse changes occur with lactose: the content is low in colostrum and increases to twice its initial value within the 1st week. It remains steady until the 5th or 6th week of lactation, after which it declines slowly and then more rapidly towards the end of lactation.

The fall in the fat content of milk from the 1st to the 5th lactation is progressive and of the order of 2 g/kg milk. Solids-not-fat content declines by approximately 4 g/kg. This fall in solids-not-fat is largely a fall in lactose; the change in protein content is small. In Friesian herds, a decrease in average lactose content from 46.9 to 44.7 g/kg milk from 1st to 3rd lactation and over has been observed.

The average fat content of bulk milk in England and Wales is highest in October and November and lowest in May and June. The protein content of milk falls to a low level in March, rises rapidly during April and May and shows a slight fall in July, followed by an increase until October, when a progressive fall occurs during the winter months. The lactose content of milk does not vary as much as protein, with values being 0.5 g/kg higher in June and 0.8 g/kg lower in September than the overall average.
The Effect of Feeding A Complete Diet on the Milk Fat Content of Milk
Authors: Slade C. F. R. , Wray J. P.
Published: June 2019

Forty-eight autumn-calving cows were fed individually during the winter period. Twenty-four cows were offered a complete diet and 24 cows were given the same dietary ingredients as in the complete diet but offered separately. The complete diet was an integral mix of ingredients in the proportion of 500 g silage dry matter (DM) and 500 g compound DM/kg. The compound offered to the cows receiving the separate ingredients was adjusted so that the total compound offered was similar on both feeding treatments. Cows offered the complete diet had a greater intake than those on the separate ingredients, with intakes of 21.4 and 19.1 kg DM/day (s.e. 0.50, P < 0.001) in the first 10 weeks of lactation; and also over the first 18 weeks of lactation, with intakes of 20.1 and 18.6 kg DM/day, respectively (s.e. 0.84, P < 0.01). The extra DM intake was largely silage. Milk yields on both treatments were similar at 31.0 1/day during the winter and there was no significant difference in live-weight gain between the treatments, with values of 22.0 and 19.8 kg on the complete and separate treatments, respectively (s.e. 9.03, NS). Milk fat content was markedly higher with the complete diet at 35.1 g/kg, compared with 31.0 g/kg on the separate treatment (s.e. 0.13, P < 0.001). At current prices, the cost of the extra silage DM on the complete treatment was 10.5 p/day and the improved value of the milk was 15.5 p/day. Another experiment showed no consistent effect on milk fat content when sodium bicarbonate was included in a complete diet. A casual observation on the commercial part of the herd at Bridgets indicated that, when 2 kg of liquid molasses replaced 2 kg of energy from cereal sources in a complete diet, milk protein content in early lactation was raised.
1.1 Computers and Their Potential: Application to Animal Production
Authors: Spedding C. R. W.
Published: June 2019

Modern computers combine the capacity not only to carry out calculations very quickly but also to make many calculations simultaneously, to remember what they have done, as well as their instructions, and to do all this using very little space and with great reliability. These abilities to calculate, record and remember far exceed those of people and, where these qualities are all that are required, computers can substitute for people — very often for many people. But, of course, agriculture as a whole does not employ many people and the scope for substitution may not be great: it is, however, likely to be greater in animal rather than in crop production.

Computers can only make decisions where adequate data are available (Blackie and Dent, 1979) and where the weight to be attached to each piece of information is pre-determined. The conceptual framework also has to be adequate, so that decisions are also pre-determined for given values of the variables considered. This is not the same thing as exercising judgement but, in fact, it can come very close to it. A computer landing an aircraft, playing chess or diagnosing a disease behaves very like a human being, and a very skilful, experienced one at that. Computers have considerable advantages in terms of speed of response to feedback and thus, in addition to the power of decision, they possess great power to control and monitor operations.

In looking to the future, therefore, it is probably not necessary to try and predict what computers will be able to do: they are already able to do most things and will be able to do virtually anything. It does not follow, of course, that they should be used just because it is technically possible: mere technical feasibility is not sufficient justification for doing anything. This is true of all technical developments and computers are no different in two important respects.
Patterns of substrate utilization from birth to weaning
Authors: Fletcher J. M.
Published: June 2019

Strategies to reduce the relatively high incidence of death and disease in young animals must be based on an understanding of the particular metabolic requirements in the period from birth to weaning. In this period, substrate availability and the pathways of substrate utilization differ from those of the foetus and of the adult. Metabolic requirements must be met from the energy stores laid down before birth and from the nutrients present in colostrum and milk. The young animal has a large glucose demand and after exhaustion of hepatic glycogen reserves this must be met by gluconeogenesis. Initiation of gluconeogenesis requires concomitant oxidation of fatty acids, either derived from adipose tissue or from the diet. The young animal is particularly susceptible to hypothermia. Non-shivering thermogenesis in brown adipose tissue uses fatty acids to uncouple oxidation from phosphorylation and also as the major oxidative substrate. In addition, non-shivering thermogenesis is dependent on a minimum concentration of circulating glucose. Shivering thermogenesis is initially fuelled by oxidation of intra-muscular glycogen and then primarily by dietary fat. Growth of white adipose tissue by deposition of dietary fatty acids is an important feature of the metabolism of many species before weaning and this may have several survival advantages.
4.3 Oral Treatment of Trace Element Deficiencies in Ruminant Livestock
Authors: MacPherson A.
Published: June 2019

Oral treatment of trace element deficiencies of livestock has a long although not always distinguished history. It has generally been the method first employed following the discovery of a trace element deficiency. Thus, Robert Fraser (1794) used oral dosing with soil to counteract the effects of cobalt (Co) deficiency in sheep; Hunter, Eden and Green (1945) dosed ewes with copper (Cu) for the control of swayback; McLean, Thomson and Claxton (1959) obtained significant growth responses following selenium (Se) supplementation of unthrifty lambs and Dynna and Havre (1963) used oral dosing with zinc (Zn) as part of the treatment of cattle suffering from a combined Zn-Cu deficiency in Northern Norway.
6.1 The Effect of Season and Supplementation on the Selenium
Status of Sheep
Authors: Wheatley L. E. , Beck N. F. G. , Lees J. L.
Published: June 2019

The effects of season and husbandry on the selenium (Se) status of four flocks, located in areas of Dyfed in Wales, were monitored over a 16-month period. The Se status of each flock was assessed from the activity of the Se-dependent enzyme glutathione peroxidase (EC 1. 11. 1. 9, GSH-Px), determined at 30°C in individual blood samples. The survey was initiated in January 1981 and samples were collected at monthly intervals from 18 ewes per flock.
6.9 Dietary Molybdenum Reduces the Effectiveness of Oral and Parenteral Treatments for Hypocuprosis
Authors: Suttle N. F.
Published: June 2019

There is widespread recognition that small increments in herbage molybdenum (Mo) concentrations can induce hypocuprosis and a recent study indicated that preventative measures might also be affected: copper oxide needles afforded less protection to ewes on high Mo diets than those on low Mo diets (Suttle, 1981 a). The effect of dietary Mo on the ability of other oral and parenteral copper (Cu) sources to alleviate hypocupraemia was therefore examined. Groups of Blackface ewes were depleted for each experiment by feeding a semi-purified diet containing 1 — 1.3mg Cu/kg DM and 4 g sulphur (S)/kg DM. Molybdenum was added as Na2Mo04, to provide an additional 4 mg Mo/kg DM to the 0.5 — 0.8 mg/kg DM present in the basal diet.
6.17 Intravenous Administration of Thiomolybdate for the Prevention and Treatment of Chronic Copper Poisoning in Sheep
Authors: Gooneratne S. R. , Howell J. McC. , Gawthorne J. M.
Published: June 2019

Chronic copper (Cu) poisoning is a well recognized problem in sheep and there is evidence that the incidence is increasing as more intensive methods of production are adopted. The interaction between Cu, molybdenum (Mo) and sulphur (S) in ruminants is well known and diets supplemented by Mo and S have been used to reduce the incidence of Cu toxicity in sheep. It has been postulated that Mo reacts with sulphide in the rumen to form thiomolybdate (TM) and that this subsequently combines with dietary and/or tissue Cu to form complexes in which Cu is unavailable to the animal. We have evaluated the response of Cu-dosed sheep to the intravenous administration of TM.
4.1 The Nitrogen Needs of Ruminants
Authors: Miller E. L.
Published: June 2019

The organizers of this symposium invited me to review factors which influence the N needs of ruminants. Such a request seems to imply that, for each class of ruminant, e.g. cattle or sheep, growing or lactating, there is a definitive N or amino acid requirement. If this is known, then diets may be formulated to provide that amount of N or amino acid and the expected level of production should be achieved. As a corollary of this approach, the determination of the nutritional characteristics of the diet, its metabolizable energy (ME), rumen degradable protein (RDP) or undegraded protein (UDP), appears to be a separate issue. While such a simplistic view has advantages for ease of diet formulation, it is unlikely to be entirely correct. In general, animal responses to increasing nutrient supply are curvilinear and do not show sharp break points defining a minimum amount of nutrient to give maximum production. Secondly, animal responses are not independent of diet and, conversely, the energy and protein values of the diet depend on the physiological state of the animal, e.g. the level of food intake influences rate of passage of digesta, the extent and site of digestion and the form of metabolites absorbed.
Principles of techniques that rely on gas measurement in ruminant nutrition
Authors: Theodorou M. K. , Lowman R. S. , Davies Z. S. , Cuddeford D. , Owen E.
Published: June 2019

In vitro gas production techniques have become popular for characterizing the rate and extent of digestion of ruminant foods. In a typical gas production study, gas (predominantly carbon dioxide) is produced as particles of substrate are fermented by rumen micro-organisms in a bicarbonate buffered culture medium. Innovations in equipment design, including automated pressure recording systems and mathematical descriptions of the gas production profiles themselves, make the techniques both simple and precise and therefore good as laboratory procedure. The technique of measuring gas is of value in ruminant science because the kinetics of gas production and substrate degradation are very closely correlated. However, although it is relatively easy to measure gas volumes and to determine the kinetics of gas production, the underlying processes that give rise to the gas in the first place are complex and not well understood. Therefore, there is concern about what is being measured in gas production studies and how this relates to the digestion process in the ruminant animal. In this paper we review some of the fundamental properties of gases, describe their behaviour in liquids and consider some of the biological and chemical factors influencing gas production. From a knowledge of how gases behave in liquids and at gas-liquid interfaces, both at ambient and increased temperatures and pressures, it is possible to deduce what is happening in gas production studies. However, although the technique is invaluable for obtaining information about the digestion of particulate substrates in anaerobic ecosystems, we conclude that gas production should be used with caution in routine food evaluation studies.
Modelling fermentation in an in vitro gas production system: effects of microbial activity
Authors: Jessop N. S. , Herrero M.
Published: June 2019

In order to understand and ultimately predict the voluntary intake and performance of ruminants, it is necessary to know the nutritional value of foods. Most recent systems for predicting nutrient supply are dynamic in nature and characterize foods in terms of the quantities of available nutrients and their potential rates of supply. The in vitro gas production system has been used to characterize the carbohydrate fraction of foods in this manner. For the technique to be able to do this, two assumptions must be satisfied. First, that the rate of fermentation is limited by characteristics of the food and secondly that the pattern of gas production correlates closely with the pattern of food fermentation.Low microbial activity within the system could invalidate both assumptions since it could (i) limit the rate of food fermentation, thus not allowing the potential rate determined by the physical and chemical nature of the food to be measured and (ii) result in partition of food carbohydrate into new microbial matter, thus reducing the amount of volatile fatty acids and hence gas produced per unit of food fermented.

The aims of this study were mathematically to simulate food fermentation within an in vitro system and to use this representation to investigate the potential effects of variation in microbial activity on the characterization of foods.
Comparison of rumen liquor and faeces from cows as sources of micro-organisms for the in vitro gas production technique
Authors: Mauricio R. M. , Owen E. , Dhanoa M. S. , Theodorou M. K.
Published: June 2019

Bioassay methods to estimate the digestibility of forages for ruminants, such as the in vitro digestibility technique (Tilley and Terry, 1963), the nylon bag technique (Ørskov et al., 1980) and the gas production methods of Menke and Steingass (1988) and Theodorou et al. (1994), require rumen fistulated animals, either to provide a suitable in situ environment or to provide rumen liquor as a source of inoculum. Not only is establishing and maintaining fistulated animals expensive, but fistulation is an invasive technique which is increasingly discouraged on animal welfare grounds. There is therefore a need to find an alternative to rumen liquor as a source of micro-organisms for bioassays.

Although the Tilley and Terry (1963) technique is widely used, it is limited by being an end-point digestibility method. Ørskov et al. (1988) showed that intake of forages and their rate of digestion in the rumen are more correlated than intake and digestibility. Thus, since 1988, there has been much interest in determining rate of rumen degradability using the nylon bag technique (Huntington and Givens, 1995). However, as indicated earlier, this in vitro technique requires fistulated animals. Recently Sileshi et al. (1996) showed that the in vitro gas production technique of Theodorou et al. (1994), offers a possibility of assessing rate of rumen degradation.

The purpose of the present experiment was to compare rumen liquor and faeces as sources of inoculum in the gas technique of Theodorou et al. (1994).
The effect of the length of the priming period on fermentation characteristics using the pressure transducer technique
Authors: Harris D. M. , Beever D. E.
Published: June 2019

The pressure transducer technique of Theodorou et al. (1984) is becoming of increasing importance in food evaluation. The main advantage over end-point procedures is the collection of kinetic data on a food. Previously such data were only obtained by sequential sacrifice or in situ techniques. Earlier work (Harris, 1996) showed that kinetics in the early stages of the incubation may not accurately simulate the processes occurring in vivo and this led to the use of a priming technique when the microbial innocula is acclimatized for 24 h to a priming food similar to the basal diet of the donor animal. This work investigates the effect of the length of priming on fermentation characteristics of two foods.

Samples of barley grain and straw were ground through a 1-mm screen and a priming food of grass silage and concentrates prepared according to the method of Harris (1996). Gas production was determined from the barley grain and straw using bovine rumen liquor after exposing the microbial population to the priming food for 0 (unprimed), 6, 12, or 24 h. Gas volumes were recorded manually and the blank corrected volumes fitted to the equation of France et al. (1993).
Broad-based calibrations of in vitro gas production of forages by near-infrared reflectance spectroscopy
Authors: Herrero M. , Jessop N. S.
Published: June 2019

There is increasing demand to obtain fast and accurate dynamic nutritional information from forages. Near-infrared reflectance spectroscopy (NIRS) offers the possibility for obtaining such information for a range of nutritional constituents of foods. Herrero et al. (1996 and 1997) calibrated in vitro gas production measurements of a single grass species by NIRS. There would be greater practical benefit if the gas production predictions could be obtained using calibrations derived from a wide range of plant species, since a single equation could be used for all forages. The objective of this study was to investigate if in vitro gas production measurements of a broad based sample population could be calibrated by NIRS.
Science and knowledge transfer – what the pig industry needs
Authors: Sheldon M J
Published: June 2019

The scientific needs of the pig industry change on an ongoing basis, partly because needs are satisfied from time to time, and partly because crises pass. However, there is something more to it than that. Changing need can be characterised as a function of the pig industry's hierarchy of scientific need. The four layers in the hierarchy, in ascending order, can be named thus: Do no harm; Stay in business; Cost less; Charge more.

Do no harm means: don't make people ill (or worse); don't pollute the environment; and don't impair the welfare of pigs in our care. These are basic qualifiers to have the right to produce pigs at all. They tend to be absolute needs where interpretation might be necessary, but where relative positions are not likely to be acceptable (i.e. the pig industry is no worse than the rest). A failure to satisfy these needs makes the pig industry a pariah, and renders all other activity in the industry irrelevant.
Non-invasive endocrine assessments in the domestic sow: towards an automated reproductive monitoring system for pig production
Authors: Pickard A. R. , Vazquez J. M. , Pemberton R. M. , Hart J. P. , Mottram T. T.
Published: June 2019

A method for monitoring the reproductive status of female pigs, using non–invasive hormone analysis was developed. Plasma and saliva samples were collected from five reproductively active sows, and analysed for oestradiol–17ß and progesterone by immunoassay. The oestradiol–17ß content of the saliva samples was also measured using a novel biosensor–based method to demonstrate, in principle, the potential to develop an automated system for hormone analysis and interpretation. A hand–held saliva sampling device was designed and built for the purpose of this experiment. Plasma and saliva samples were collected for 3.5 months from four of the five sows. The vascular access port implanted into the fifth sow failed; therefore she could only be used for saliva collection. Saliva sampling was 100% successful for the first two weeks of the study. Over the entire sampling period, daily and twice weekly samples could be collected on 86% of the attempts made. Both progesterone and oestradiol–17ß were measured in saliva samples using conventional immunoassay techniques.
The relationship between pre weaning social behaviour and racing performance in Thoroughbred horses
Authors: Randle H , Counsell T , Wilton K
Published: June 2019

Vast sums of money are invested in training racehorses, yet race earnings rarely cover training costs. The ability to accurately predict potential racing performance prior to training would be advantageous. Although a link between equine behaviour and later racing success has been suggested, no single measure has yet been identified, mainly due to the complex relationships between behavioural attributes, particularly those of a social nature. The influence of gender is also unclear. According to The Mental Health Model of Sport Performance a degeneration in mental state is reflected by a decline in performance. The success of over 70% of human athletes was identified using behavioural measures of personality. Reportedly equine ‘winners’ are ‘calm’ whilst ‘losers’ are ‘aroused’. Such equine ‘reactivity ‘ (‘temperament’) has traditionally been investigated using contrived experiments. This study aimed to carefully examine equine social activity by exploring multiple aspects of social behaviour whilst avoiding the restrictive concept of dominance.
Biosecurity strategies for conservation of farm animal genetic resources
Authors: Wrathall A.E. , Simmons H.A.
Published: June 2019

The foot-and-mouth disease (FMD) epidemic in the U.K. in 2001 highlighted the threat of infectious diseases to rare and valuable livestock and stimulated a renewed interest in biosecurity. Not all diseases resemble FMD, however; transmission routes and pathological effects vary greatly, so biosecurity strategies must take this into account. Realism is also needed as to which diseases to exclude and which will have to be tolerated. The aim should be to minimise disease generally and to exclude those diseases that threaten existence of the livestock, or preclude their national or international movement. Achieving this requires a team effort, bearing in mind the livestock species involved, the farming system (‘open’ or ‘closed’) and the premises. Effective biosecurity demands that practically every aspect of farm life is controlled, including movements of people, vehicles, equipment, food, manure, animal carcasses and wildlife. Above all, biosecurity strategies must cover the disease risks associated with moving the livestock themselves, and this will require quarantine if adult or juvenile animals are imported into the herd or flock. Reproductive technologies such as artificial insemination and embryo transfer offer much safer ways for getting new genetic materials into herds/flocks for breeding than bringing in live animals. Embryo transfer is especially safe when the sanitary protocols promoted by the International Embryo Transfer Society (IETS) and advocated by the Office International des Epizooties (OIE: the ‘World Organisation for Animal Health’) are used. It can also allow the full genetic complement to be salvaged from infected animals. Cryobanking of genetic materials, especially embryos, is another valuable biosecurity strategy because it enables storage for contingencies such as epidemic disease or other catastrophes.
Social organisation and dominance in relation to resource ascendancy within a selected group of weaned foals
Authors: Tracey S. , Verwiji R. , Bland I. , Whitaker T.C.
Published: June 2019

Houpt et al (1977) stated that injuries sustained during dominance hierarchies, and poor nutritional condition of low ranked horses are the most common and serious equine behaviour related problems. Often aggression patterns are exhibited over resource dominance. If optimum management conditions are to be attained, regard for social structure, temperament and dominance within groups is paramount; this may be especially important where enclosed barn or stable environments are used. Studies of social organisation often assume linear relationships, unfortunately this may obscure irregularities found within the social structure (Martin and Bateson 1993, Lehner 1996). This study investigates social structure and how dominance determines resource (concentrate feed) ascendancy.

A group of nine foals (n = 5♀,n = 4♂) were directly observed whilst being fed concentrates within an enclosed barn (Figure 1), daily for 40mins over a 25 day period. Dominance and displacement behaviours were observed and collated at 4min intervals via scan sampling. All foals were observed simultaneously and continuously.
The use of branding within the equine related charity sector and the implications of brand orientation
Authors: Abraham D. M. , Walsh Rita
Published: June 2019

The Charity Commission website lists in excess of 100 equine charities (Charity Commission, 2003) and this figure does not include those whose annual income is under £1,000. The size and nature of equine related charities varies enormously. In 2002 the top 6 equine charities (listed below) had a combined income of £40m and were responsible for rescuing approximately 600 horses, ponies and donkeys (Peplow, 2003).

Blue Cross

International League for the Protection of Horses

Home of Rest for Horses

The Donkey Sanctuary

Redwings

Horse and Pony Protection Association

Whilst these larger charities have grown organically over the years, many smaller charities are failing to survive and are in some situations having to be ‘rescued’ themselves by their larger counterparts. The public, consisting of present and potential donors, are offered a vast choice of charities to support. Philanthropic behaviour has at best stagnated in recent years (Sargeant & Lee, 2002).
The climate of the Estuary and Firth of Clyde
Authors: Smith K.
Published: June 2019

Synopsis

The climatic character of this particular shoreline environment is analysed with a major emphasis on the contrasts between the upper estuary and the Clyde coast. The relatively mild, dry and sunny conditions along much of the Ayrshire coast are described and explained, although attention is also drawn to the effects of smaller-scale variations in topography, especially on temperatures. Sea breeze mechanisms are identified and illustrated with reference to a specific event.
Clyde Sea hydrography
Authors: Edwards A. , Baxter M. S. , Ellett D. J. , Martin J. H. A. , Meldrum D. T. , Griffiths C. R.
Published: June 2019

Synopsis

A front on the Great Plateau separates tidally mixed water of the North Channel from quieter less saline surface layers of the Outer Firth. These water bodies exchange about 1·6 × 104m3 s−1, leading to a residence time of two months in the Outer Firth surface layers. The position of the front is determined by the balance of mixing and buoyancy supply. The wind modulates weak tidal currents in the Outer Firth by driving surface currents and setting up deeper compensation flows. Deep water in the Arran Deep and Kilbrannan Sound is irregularly renewed by inflow of dense water over the Eastern Plateau from autumn to spring of about 1 × 104m3 s−1 but stagnates in summer below a thermocline. A minor part of this renewal comes over the Davaar sill into Kilbrannan Sound.

Bottom water of the fjordic sea-lochs is isolated in summer and renewed during the winter. The renewals occur by density currents flowing in from the sills and these produce a characterising grading of the bottom sediments from coarse to fine away from the sills.