bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fragmentation of Comet Shoemaker-Levy 9's Nuclei During Flight Through the Jovian Atmosphere
Authors: Sekanina Z. 
Published: June 2019

AbstractFragmentation dominates the ablation process of cometary type impactors during their atmospheric flight. Models that account for it imply that a kilometer-sized nuclear fragment of comet Shoemaker-Levy 9 has disintegrated almost completely by the time of its terminal explosion, at a pressure level of <1 bar. This result, consistent with impact scenarios based on precursor-event timings, suggests that the initial masses of two fragments, K and R, were between 7×1014 and 5×1015grams apiece.
Optical Properties of Fluffy Particles
Authors: Stognienko R. , Henning Th. , Ossenkopf V. 
Published: June 2019

AbstractFor particles grown in the two limiting cases of coagulation (ballistic particle-cluster agglomeration and ballistic cluster-cluster agglomeration), lower and upper limits of the extinction at wavelengths from 1 μm to 1 mm are derived. The particle sizes are in the Rayleigh limit and the number of constituent grains in each particle is constant. Effective medium theories, the discrete dipole approximation and the discrete multipole method are applied to compute the optical behaviour of the coagulated particles. The spectral representation for inhomogeneous media is employed to investigate topology effects systematically.
Properties of Interstellar Dust
Authors: Dorschner Johann 
Published: June 2019

AbstractIn this review, the picture of the interstellar dust is outlined from the viewpoint of its role in galactic evolution. The modern concept of distinct dust populations is presented. The properties of the dust grains in the diffuse interstellar medium and in the molecular clouds are described. Some unsolved problems and future perspectives of interstellar dust research are pointed out.
The Dust in β Pictoris Systems
Authors: Fajardo-Acosta S.B. 
Published: June 2019

AbstractThe bright 10 μm excess emission of β Pic stars allows detailed spectroscopy of their warm circumstellar solid material. The silicate features in β Pic and 51 Oph are broader and contain more structure than interstellar and most circumstellar emission features. The β Pic and 51 Oph features are remarkably similar to those in comets Halley, Bradfield 1987s, Levy 1990 XX, and Mueller 1993a which have 11.3 μm emission features characteristic of crystalline silicates. In contrast, other β Pic-type stars (ζ Lep and β UMa) show weak 10 μm emission from larger, amorphous dust grains. Some comets such as Austin 1990 V emit similar weak 10 μm features.
Milk utilization and manipulation of composition in the future
Authors: Banks W. , Muir D. D. 
Published: June 2019

SUMMARYMilk composition varies greatly throughout the year, due largely to the effects of the diet of the cow and the stage of lactation. Whilst such variations go unremarked with bottled and cartoned milk, they are of major importance to manufacturers who use milk as a raw material. The most obvious example is when the yield of a dairy product is affected, e.g. in Scotland, the volume of milk required to produce 1 kg butter varies between 21.1 and 23.3 1 at different times of the year.In addition, however, some of the more subtle changes in milk composition either affect product quality, e.g. the ease with which butter may be spread, or cause processing difficulties, e.g. instability during heating processes. This paper reviews some of our current knowledge on the relationship between milk composition and the properties of some dairy products — butter, whipping cream, Cheddar cheese, ultra-heat treated milk and full-cream evaporated milk. The aim is to identify those milk components that affect each product or process and then enquire how milk composition may be altered to effect improvements — whether at the farm by dietary manipulation or at the creamery by technological adjustment.It is believed that all the evidence indicates that, despite difficulties due to restrictive legislation, the answer must lie at the creamery. The farmer should concentrate on producing desirable milk solids at the lowest possible cost and leave the technologist to do the fine tuning that leads to improved products.
Breeding and milk quality
Authors: Mulholland J. R. 
Published: June 2019

SUMMARYThe broad principles of animal breeding are outlined and the ‘normal-probability curve’ is used to illustrate how progress should be made in improving the genetic merit of dairy cattle. The importance of genetically correlated responses is discussed, together with the need to test progeny. The way in which genetic improvement accumulates in dairy cattle is described and the need to use high-production sires with reliable proofs is stressed. Present and proposed milk-quality payment schemes require that selection should be based on the yield of recorded solids as the best indicator of total solids. As cattle breeding involves a long time-scale, it is not always possible to take into account short-term changes in the value of milk constituents. The effect of changing values upon the ranking of bulls is small and, for the foreseeable future, the use of the weight of recorded solids, i.e. the weight of fat plus the weight of protein, as the selection factor, is likely to maximize progress. The relationship between functional type and herd life is examined. It is concluded that there is no obvious relationship between type and herd life; yield is the dominant factor in determining the length of time an animal remains in the herd. Any breeding programme should therefore place maximum emphasis on production.
Research and development implications for the future
Authors: Wilson P. N. , Lawrence A. B. 
Published: June 2019

Choice of breedA model should be developed to allow the selection of the optimal breed on the basis of production traits and economic efficiency.Choice of selection methodNew breeding schemes to replace the current widespread use of progeny testing should be examined critically and, in particular, breeding schemes incorporating multiple ovulation and embryo transplant should be assessed.Identification of marker traitsResearch to evaluate the relevance of marker traits to milk quality should be pursued.Genetical engineeringLong-term prospects of applying genetical engineering techniques to cattle should be assessed in terms of desk studies.Nutritional manipulation of milk fatThe biochemical and metabolic aspects of lipid protection in the rumen should be examined further.Nutritional manipulation of milk proteinFurther studies should be undertaken to examine the effects and possible benefits of protein and specific amino acid protection.New milk productsWork should be conducted to increase the range of marketable products of high added value, particularly new types of cheese for export.Alleged relationship between milk fat and coronary heart disease (CHD)The alleged causal relationship between dietary fat and CHD should be examined critically, particularly the definition of safe levels of serum cholestrol in man.
Milk Composition in Herds With High and Low Mastitis Cell Counts
Authors: Booth J. M. , Harding F. 
Published: June 2019

Fifty herds with the highest annual average mastitis cell counts in England and Wales were compared with 50 herds with the lowest cell counts. The milk-quality test results of these herds for milk fat, protein and lactose contents, and total bacterial count (TBC), over the 6 winter months, October 1982 to March 1983, were examined.The herds with high cell counts had an arithmetic mean of 2.50 × 109 cells/1 and the herds with the low cell counts had 0.117 × 109 cells/1. The milk-quality test results were: milk fat, 39.8 and 40.0 g/kg; protein, 33.2 and31.5 g/kg; lactose, 42.8 and 46.9 g/kg; and TBC, 139 and 12.0 × 106/1 for the herds with the high and low cell counts, respectively. There were highly significant differences in protein and lactose contents and in TBC. When the average monthly results were compared, these differences were statistically significant in all months. On average, lactose was 9% lower and protein 5% higher in the herds with the high cell counts when compared with the herds with the low cell counts.
By-products from cereal, sugar beet and potato processing
Authors: Barber W. P. , Lonsdale C. R. 
Published: June 2019

From just five industries in the United Kingdom — brewing, distilling, milling, sugar extraction and potato processing — at least 2.7 × 106 mega joules (MJ) of metabolizable energy (ME) and 4 × 105 tonnes of crude protein (CP) are available annually to livestock farming as by-products. This is equivalent to 1.6 × 106 tonnes of barley and 4.7 × 105 tonnes of soya bean meal, although in some cases nutrient density may differ somewhat from that found in barley or soya.A large proportion of the by-products available is already used in animal feeds, either djrectly by the farmer or through inclusion in compound feeds which are then used as components of balanced rations.The materials available are potentially alternative feedstuffs to conventional forages or concentrates. As such they will only form part of a balanced ration and it is in this context that their relative value and usefulness can be judged. In many investigations there has been a tendency to consider particular by-products in isolation and as a consequence any nutrient imbalance has been highlighted to the detriment of the material as an alternative feed. Very few straight feedstuffs contain ratios of nutrients balanced for particular levels of animal production and invariably rations for livestock consist of blends of different materials. Whilst extremes of nutrient imbalance may be identified in individual by-products they are, none the less, wholly suited to blending with other by-products or feeds of contrasting nutrient content in order to produce a completely balanced ration.
6.8 Effects of Iron and Molybdenum on Copper Metabolism in Calves
Authors: Bremner I. , Phillippo M. , Humphries W. R. , Young B. W. , Mills C. F. 
Published: June 2019

Although it is well established that changes in dietary iron (Fe) intakes can influence copper (Cu) metabolism in animals, little attention has been paid to their importance in causing Cu deficiency in ruminants. The realization that silages frequently contain large amounts of Fe, mainly as a soil contaminant, prompted us to assess the potency of Fe as a Cu antagonist and to compare its effects with those of molybdenum (Mo).In one experiment, 27 male Friesian calves, aged about 3 weeks, were allocated to three treatment groups and given a milk-substitute ration containing 2.5 mg Cu and 50, 250 or 500 mg Fe (as FeCl3.6H20)/kg DM. Liver biopsies were taken after 8 weeks and analyzed for Cu and Fe. As expected, tissue Fe increased by as much as 50% with increasing Fe intake. However, there were no effects of Fe on hepatic Cu retention in these pre-ruminant calves (liver Cu was 343, 372 and 390 mg/kg DM, respectively: SEM = 40).
Cattle systems in the hills and uplands
Authors: Lowman B. G. , Chalmers A. J. 
Published: June 2019

AbstractThe vital criterion in selecting a beef system is to ensure that feed requirements match supplies produced on the farm, with a minimum of conflict with other enterprises. Grass must form the basis of any system with emphasis given to grazing. In quantifying feed supplies, the ability of the suckler cow to store summer grazing, as body fat, must also be included.Traditionally, enterprises have been evaluated on a Gross Margin basis. On combined beef/sheep units, such comparison must be carefully interpreted if misleading conclusions are to be avoided. Adequate supplies of autumn grazing arc key components for both enterprises. Failure to meet these, results in reduced individual performance or increased winter feed requirements. The grassland requirements of both enterprises must therefore be complementary.May calving and selling calves store in the spring, prior to lambing, achieves these objectives. An important component of such a breeding enterprise is the tax-free, capital accumulation via the herd basis and beneficial effects on the cash flow. Where capital for investing into breeding stock is unavailable, the purchase of week-old calves in January, for sale at 330 kg the following spring or retained for grass finishing, can also integrate successfully with the ewe flock, minimizing dependence on conserved winter feed and accommodation.
Impacts of livestock on crop production
Authors: Powell J. M. , Pearson R. A. , Hopkins J. C. 
Published: June 2019

AbstractIn sub-Saharan Africa (SSA), the association of crops and livestock in mixed farming systems generally benefits both enterprises. This paper focuses on the main contributions of livestock to crop production: the use of manure and animal draught power to produce crops and the investment of income from livestock into technologies that benefit crop production. In low-input, grazing-based feeding operations, manure is a vital soil fertility amendment. In these systems, penning livestock overnight on fields, fallow between cropping periods, returns both manure and urine to the soil and results in much higher crop yields than if manure only is gathered from stalls and spread onto fields. However, most farmers have insufficient manure to sustain food production. Nutrient harvests often exceed nutrient inputs, requiring a much greater use of fertilizers to arrest soil nutrient depletion. The opposite may be true for mixed farming where livestock are given food in confinement. In these emerging systems, the continuous importation of food (and fertilizer) can result in nutrient surpluses with subsequent soil nutrient build-up and loss. The contribution of animal power to crop production is relatively new in Africa. Animal power affects the amount of land cultivated by farmers, crop selection, the yield per farm and per ha, and on the participation and work load of people (family members and outside labour) involved in crop production and its associated activities. In addition to the impacts of manure and draught power on crop production, income derived from livestock is often invested in inputs that enhance crop production. At the ‘micro’ level, livestock income influences crop production (1) directly by allowing households to invest in productive inputs such as fertilizer, hired labour, and carts and (2) indirectly by allowing poor households to improve their nutritional status and, therefore, the productivity of their most important resource, their own labour. At the ‘macro’ level, increased livestock exports have a large stimulating effect on the demand for locally produced goods and services, particularly basic food crops. Thus, increasing the productivity of the livestock sector, including an emphasis on the policy and institutional environment influencing marketing and trade, is an important element of a development strategy focused on stimulating economic growth and alleviating poverty.
Farmers' participation in agricultural research: experiences from Ethiopia
Authors: Konde Alemayehu 
Published: June 2019

AbstractLivelihoods of most farmers in different ecological settings are local, extremely complex, diverse, dynamic and unpredictable. The situation of low-income farmers is even more complex: poor infrastructure; diverse and risk-prone agro-ecological conditions; strong interactions between crop, livestock, tree and fodder components of the farming system, between agriculture and the management of common resources, combining cropping and herding with off-farm activities; and diverse socio-economic conditions.Until recently, agricultural research in developing countries had predominantly been conducted under conditions ‘controlled’ by researchers, on topics chosen predominantly by researchers and in ways largely determined by researchers. Concern over the complexity and diversity of situations faced, especially by low-income farmers, paved a way to the steady development of a range of participatory approaches which, in turn, led to the increasing recognition of farmers’ participation (though in varying degrees) in the research process, if research were to generate and spread appropriate agricultural technologies with some prospect of uptake by farmers.The purpose of this paper is to provide information on ‘Farmers’ Participatory Research’ (FPR), i.e. research in which smallholders play leading roles, from diagnosis through implementation to assessment of results and dissemination. With particular emphasis on recent experiences in Ethiopia, the rationale, techniques, application and some results of FPR, carried out in different settings at different times of the year, are reviewed.The paper highlights local peoples’ abilities in identifying and prioritizing their own problems; significant rôles, if allowed to participate, in identifying and prioritizing the ‘best-bets’ and, or, researchable issues, carrying out and evaluating research. The degree of smallholders’ participation in setting the research agenda, their involvement in the research process and ultimately success or failure depend on various factors. Of these: nature and state of problems limiting agricultural productivity; types and stages of research; expected duration of the research; time and resource availability; and favourable policy issues are considered to be amongst the most important.
Screening of factors favouring the maintenance of rumen protozoa in a dual outflow continuous fermenter
Authors: Broudiscou L.-P. , Papon Y. , Fabre M. , Broudiscou A. F. 
Published: June 2019

For the past years in Europe, the need for reliable alternative techniques to animal experimentation has been urged by ethical and legal prescriptions. In ruminant nutrition, dual outflow stirred-tank reactors (Hoover et al., 1976; Merry et al.,1987) have proved to be suitable for the accurate control of environmental conditions to study the metabolism of rumen microbes. Their ability to support a varied ciliate population, however, is uneven. As protozoa are major agents in the rumen microbial community, investigating the best set of general operating conditions to maintain their population at high levels is an important issue.The study was conducted in six dual outflow continuous fermenters (working volume of 1.11) supplied with 30 g/day of a pelleted diet made of 750 g orchard-grass hay and 250 g ground barley per kg. The vessels were inoculated with the rumen contents from four wethers, each equipped with a rumen cannula and given a similar diet. They were continuously infused with an artificial saliva containing: Na2HPO4.12H2O 6.157 g/l, NaHCO3 5.268 g/l, KHCO3 0.597 g/l, NaCl 0.305 g/l, HC1-cysteine 0.4 g/l and alcalinized to pH 10.0 with 1.63 g/l NaOH. The fermentation broth was separately complemented with 31.7 mg CaCl2, 47.5 mg MgCl2 and 0.755 g (NH4)2SO4 per day.
A Direct Marketeers View
Authors: Butler J 
Published: June 2019

I was a farm manager of 2,500 acres, cereals, sugar beet, vegetables, milking cows, suckling cows and outdoor sow unit producing weaners. I moved to Mells in Suffolk 26 years ago and set up a 200 sow indoor unit producing weaners before turning that into 350 sow unit, finishing half of the progeny and selling the other half as weaners.In 1993 I set up a 600 Cotswold outdoor sow unit, producing weaners for Louis Dreyfus Livestock (LDL). My landlord was and still is a partner in the business. We have a very simple partnership, he provides the land, I run the business with no cost to each other; everything else is 50-50. After four years LDL wanted to get out of pigs altogether so we bought the herd. We then went on to finish pigs outdoors in large finishing kennels with runs, which was not brilliant in wet conditions!
The effect of floor type on ammonia emission, welfare, health and behaviour of growing pigs
Authors: Breuer K. , Kay R.M. , Demmers T.G.M. , Day J.E.L. 
Published: June 2019

AbstractIn order to reduce ammonia emissions from pig housing systems, the Council of Europe proposes the use of part slatted flooring in preference to fully slatted flooring, but the effects of such changes on the health and welfare of pigs in the UK has not been defined. The aim of this experiment was to investigate the effects of different floor types on the emission of ammonia, behaviour and welfare, physical performance and respiratory and enteric health of growing/finishing pigs. This involved three replications of five treatments: 1) UK fully-slatted, 2) UK fully–slatted with rubber matting over 50% of the slats, 3) UK fully–slatted with “structural” modifications which involved “paving” over 50% of the floor and partitioning off the slurry channel beneath the solid floor, 4) UK part–slatted, and 5) novel Dutch partslatted with UK pig stocking density. Groups of 10 pigs (balanced for gender) weighing approximately 40kg were on–test for 10 weeks.
Water movement and the simulation of storm surges in the Firth of Clyde
Authors: Townson John M. , Collar Richard H. F. 
Published: June 2019

SynopsisThe basic mechanisms governing the general circulation of water in the Firth of Clyde are reviewed with particular reference to their changing relative importance throughout the system, this including the inner estuary. Attention is then focused on the effect of storm surge. A numerical model for the depth-integrated equation of motion is applied to the surges recorded in 1972 and 1979. The proportion of surge generated within the outer firth is thereby assessed.
The status of fish populations in the Clyde Estuary
Authors: Henderson Anne R. , Hamilton James D. 
Published: June 2019

SynopsisChanges in the status of fish populations in the Clyde Estuary between Woodhall and Glasgow since 1978 are described and data presented on species composition and distribution, temporal and spatial fluctuations in abundance and biomass and length frequency data for certain species are analysed.The seaward part of the estuary is colonised by marine and euryhaline marine species dominated by flounder, while the ‘city reaches’ have a fresh water component dominated by three-spined stickleback and eel in addition to several euryhaline species, e.g. sand-goby and saithe.The extent of biological recovery of the estuary from severe organic pollution can be gauged from the presence now of thirty-four species, including nineteen in the city reaches which were virtually fishless in the mid nineteenth century. The upper estuary is now able to support resident and migratory fish for much of the year, but species composition and abundance are markedly affected by seasonally variable fresh water flows to the estuary affecting primarily dissolved oxygen and salinity, leading to mortalities among resident species and providing a barrier to migrants.
Recent changes in numbers of waders on the Clyde Estuary, and their significance for conservation
Authors: Furness Robert W. , Galbraith Hector , Gibson Iain P. , Metcalfe Neil B. 
Published: June 2019

SynopsisThe Clyde Estuary is recovering from gross pollution. In the early 1970s high densities of a small number of species of intertidal invertebrates tolerant of organic enrichment and low oxygen levels provided rich feeding for large numbers of dunlin, redshank, lapwing, oystercatcher and curlew. Winter numbers of the first three species have now declined considerably. The declines cannot be attributed to national changes in wader numbers and are not due to changes in breeding habitats or lack of reproductive success in particular regions, since each species wintering on the Clyde Estuary breeds in a different area. The most likely explanation of the decline, which is most pronounced in the species highly dependent onCorophium volutator, is either that reduced organic pollution has reduced the densities of the main prey, or that higher oxygen levels over the mudflats have allowed fish, particularly flounders, to enter the estuary and compete with the waders for the available prey. Although there is evidence of some birds having moved to other wintering areas, the fate of most birds is unknown.