bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coherent Vacuum-UV Sources Using Nonlinear Optics
Authors: Puell H. B. , Scheingraber H. , Vidal C.R. 
Published: June 2019

For investigating diatomic and triatomic molecules of astrophysical interest in the vacuum UV using the methods of laser spectroscopy we have set up several systems for generating coherent vacuum UV sources. Since we are interested in tunable and narrow banded (0.1 - 6. 01 cm ) sources it is advantageous to employ the methods of nonlinear optics.Recently, experiments of the third harmonic generation in the Rb-Xe system. have been performed and a quantitative interpretation up to the highest conversion efficiencies of a few percent has been given. On the basis of these experiments we have investigated the optimum conditions for third harmonic generation in isotropic media. It has been possible to solve the third order problem analytically and it can be shown that the intensity conversion efficiency depends in the limit of large input intensities only on the wavelength dependent nonlinear susceptibilities of the nonlinear medium. For a Gaussian beam it can be shown that a Na-Xe system, for example, is capable of providing an energy conversion efficiency of up to 40% for the Nd:glass laser.
Investigation of Laser Produced Plasma Using Space Resolved Soft X-Ray Al Spectrum and Multi-Layer Target Technique
Authors: Zmora H. , Zigler A. , Schwob J. L. 
Published: June 2019

H and He-like Al Lines and their inner-shell satellites were obtained from Al and Polyethylene layered targets irradiated by a Nd-glass laser at a power flux of 2.1013 W/cm2 . Spatial resolution was achieved using a flat crystal spectrograph incorporating a wire shadow technique. Spatial profiles of Te and ne in the expanding plasma were deduced from line intensity ratios.By varying the Al layer location in the target, the non-thermal origin of Al Kα radiation is investigated and the penetration depth of the heat wave front is determined. Comparison is made with classical transport mechanisms.
Line Formation in Multi-Dimensional Media
Authors: Jones H. P. , Skumanich A. 
Published: June 2019

AbstractThe flux divergence technique of Athay and Skumanich (1967) is generalized for application to media whose properties vary in more than one spatial dimension. In this method, the flux divergence is viewed as an integro-differential functional of the source function. The source function is then expanded in terms of basis functions along characteristic paths, and, with the help of various interpolations, the flux divergence is converted to an approximate linear algebraic operator on a discrete spatial grid. A large but finite set of linear, inhomogeneous, simultaneous algebraic equations with known matrix coefficients is thus generated and is solved by direct matrix inversion for the source function at each point of the spatial grid.Some aspects of the accuracy, stability, and computational convenience of the technique are discussed. Sample solutions for depth dependent, axially symmetric variations of temperature are shown.
Binaries with Compact Components: Theoretical and Observational Challenges
Authors: Podsiadlowski Ph. , Rappaport S. , Pfahl E. 
Published: June 2019

AbstractWe report on recent progress in our theoretical understanding of X-ray binaries, which has largely been driven by new observations, and illustrate the interplay between theory and observations considering as examples intermediate-mass X-ray binaries, irradiation-driven evolution, ultraluminous X-ray sources and neutron stars with low-velocity kicks.
RX J0513.9-6951 and V Sagittae: Accretion Wind Evolution, A Key Evolutionary Process to Type IA Supernovae
Authors: Hachisu Izumi 
Published: June 2019

AbstractA new self-sustained model for long-term light-curve variations of the supersoft X-ray sources RX J0513.9–6951 and V Sge is proposed based on an optically thick wind model of mass-accreting white dwarfs (WDs). When the mass accretion rale to a WD exceeds the critical rate of ~ 1 x 10–1M⊙. yr–1, optically thick strong winds begin to blow from the WD so that a formation of common envelope is avoided. The WD can accrete and burn hydrogen-rich matter on the surface of the WD at the critical rate. The excess matter transferred to the WD above the critical rate is expelled by winds. This is called “accretion wind evolution.” This ejection process, however, occurs intermittently because the mass transfer is attenuated by strong winds: the strong winds collide with the secondary surface and strip oil the surface layer of the secondary. Properly formulating the mass-stripping effect and the ensuing decay of mass-transfer rate, we are able to reproduce the transition between the optical high/X-ray off and optical low/X-ray -on states of the supersoft X-ray sources RX J0513.9–6951 and V Sge. Thus these two objects are the lirst examples of accretion wind evolution, which is a key evolutionary process in a recently developed evolutionary path to Type la supernovae.
Light Curves of Candidate Pre-Cataclysmic Binaries
Authors: Tappert С. , Gänsicke B. Т. , Mennickent R. E. 
Published: June 2019

We present the results of time-series photometry for a sample of candidate pre-cataclysmic variables.The observations were conducted on 2002-09-17 to 22, 2002-10-16 to 22, 2003-04-08 to 11, 2003-05-13 to 16, and 2003-06-18 to 21, at the 90 cm telescope at CTIO, Chile, using a 2kx2k CCD and a Johnson R filter. Additionally, data for the three targets LBQS 1144+0111, LBQS 1232+1335, and LBQS 1327—0242, were obtained in service mode at the 1.3 m CTIO telescope with ANDICAM. The latter observations consisted in a series of ~2 h runs for each object on five consecutive nights, also in R.
Dwarf Nova-Like Outburst of Short-Period Intermediate Polar HT Camelopardalis
Authors: Ishioka R. ,   VSNET Collaboration Team
Published: June 2019

Our time-series photometric observations of a short outburst of HT Cam in 2001 strongly suggest that disk instabilities occurred during the outburst.HT Cam is a cataclysmic variable identified as the optical counterpart of the hard X-ray source RX J0757.0+6306, discovered during the ROSAT All-Sky Survey. Tovmassian et al. (1998) suggested that this object is an intermediate polar with a shortest orbital period of 80.92min and a spin period of 8.52min. However, the existence of dwarf nova-like outbursts and the short orbital period allowed an alternative interpretation that it may be an SU UMa-type dwarf nova or WZ Sge-type stars (Tovmassian et al. 1998).
Some Effects of Cow Nutrition on Milk Composition
Authors: Roberts D. J. , Ferns H. R. 
Published: June 2019

The milk composition responses in five feeding trials were as follows.1. A study of silage quality showed that the fat content was lower (39.9 v. 43.1 g/kg, s.e. of difference 1.00) and the protein content was higher (35.0 v. 33.7 g/kg, s.e. of difference 0.48) with silage cut three times per season compared with silage cut twice per season.2. Silage offered as a buffer food overnight in the early part of the grazing season reduced milk yield (18.9 v. 19.9 kg/day, s.e. of difference 0.26) and increased fat content (39.4 v. 35.6 g/kg, s.e. of difference 0.50) when compared with grazing only. Silage offered in the late grazing season did not affect milk yield but increased fat content(44.1 v. 41.3 g/kg, s.e. of difference 0.94). There was no significant effect on protein content.3. A concentrate containing 18 g crude protein/kg was offered at rates of 0.30, 0.375 and 0.45 kg/kg milk plus silage ad libitum. The fat contents were 38.0, 38.6 and 36.1 g/kg and the protein contents 30.3, 31.2 and 32.1 g/kg, respectively.4. In two experiments comparing flat-rate concentrate feeding with feeding according to yield, no significant differences were found in milk yield, fat and protein contents.5. In a study of body condition at calving, cows calving at score 2 had milk fat contents similar to cows calving at score 3 but there were differences in the fatty acid composition of the milks. The cows calving at score 2 produced milk with a higher protein content than those at score 3 (32.8 v. 30.7 g/kg, s.e. of difference 0.85).
The Diagnosis of the Causes of the Production of Herd Milk With Low Fat, Protein and Lactose Contents
Authors: Ferns H. R. , Roberts D. J. 
Published: June 2019

A dual approach is required to diagnose the cause or causes of the production of herd milk of inferior compositional quality. By studying the results of the analysis of a milk sample in conjunction with accurate information obtained at the farm, it is frequently possible to trace the origin of the problem and, hence, give reliable advice to overcome it. Simple flow diagrams are available as an aid to the Adviser and the diagrams for milk fat, protein and lactose are illustrated.Case histories are available to illustrate the approach used and indicate the effects of advice on milk production and compositional quality. When diagnosis is difficult, a more detailed investigation is necessary. This might involve the sampling and analysis of foods and the analysis of samples of milk from individual cows. The use of automated infra red spectrophotometric instruments for milk analysis and the processing of results using computers, enable large numbers of samples to be dealt with expeditiously and at low cost.
The management and performance of sheep in the hills and uplands
Authors: Vipond J. E. , Gunn R. G. 
Published: June 2019

AbstractAn assessment of performance of Scottish flocks was made using DAFS census data to impute a lambing percentage. Results showed levels of lambing percentage were generally below potential and threatened viability of hill units.A postal survey of hill farmers' views on constraints to production was carried out in the Grampian region of Scotland. Farmers were asked for five technical problems in order of importance that they faced and also what management changes, new products or information had affected or would affect their sheep farming. Analysis of 120 replies from farmers owning about 500 000 ewes indicated farmers recognised three major problems. These were tick-borne disease, pneumonia and abortion which accounted for 30% of the problems. Farmers viewed the next most important problems in order of importance as footrot, broken mouth, predators, head fly, barrenness, neonatal deaths, worms, photosensitisation, vaginal prolapse, mastitis, feeding costs, hypothermia, bracken, orf, fluke, pregnancy toxaemia and marketing difficulties. These accounted for a further 40% of problems. Farmers assessed the most important technical advances to be (in order of importance) pregnancy scanning, fluke and worm drenches, pasteurella vaccine, feeding ewes before lambing, feed blocks, clostridial vaccines, land improvement and trace element supplementation. An assessment of technological answers to farmers' problems indicated that, although some technical problems remained unsolved, many practical solutions had been demonstrated but not yet fully taken up by farmers.
Constraints to development of extensive livestock systems: experiences from southern Ethiopia
Authors: Coppock D. L. 
Published: June 2019

AbstractThis paper reviews pastoral research and development perspectives generated from the southern Ethiopian rangelands during the 1980s. This system was selected as a case study of constraints in African pastoral development because the experiences from both research and development are fairly well documented and integrated. Until recently, the Boran managed a production system that was fairly typical of semi-settled, traditional pastoralism in East Africa. However, the Boran today are in a state of considerable change that has been induced primarily by a long-term decline in the per capita supply of cow's milk, the traditional dietary staple. This imbalance has resulted from steady growth in the human population in combination with density-dependent fluctuations in cattle production. Other major changes in pastoral, social and economic attitudes have occurred as a result of population pressure and exposure to the inhabitants of small towns that have emerged as a result of development of rural infrastructure since the 1970s. Overall, this pressure has led to increased instability and vulnerability of the pastoral population, but also offers new windows of opportunity for the application of technical, but especially policy-oriented, interventions. It is suggested that constraints to implementing successful development activities here lie more in the limitations of external institutions and the national economy, rather than within the Boran system. Long-term population trends, and opportunities for development interventions over the short term, will also be obscured by inter-drought cycles of cattle production that produce complex system interactions. Greater appreciation of the effects of such cycles on the social and economic behaviour of pastoralists could facilitate more effective development planning.
Environmental choices of farm animals
Authors: Nicol C J. 
Published: June 2019

AbstractTo assess farm animal welfare we need to understand how animals make choices and how these choices relate to preference strength. Studies of environmental choice can be categorized by the method used to investigate them, or by the underlying basis on which the animal is choosing. Choices made between resources that vary along a single dimension should meet certain criteria e.g. those of transitivity. Choices made between resources that vary along more than one dimension may or may not meet these criteria, depending how the animal evaluates each option. Understanding how farm animals choose will allow the results of individual experiments to be applied in a wider context. It is also important to know how preferences are formed during development. Evidence suggests that preferences for nests and pecking substrates in hens may be influenced by prefunctional experience. Experimental data from studies of environmental choice may enable us either to provide important resources in commercial systems, or to provide facilities for animals to continue to make their own decisions.
Social choices in farm animals: to fight or not to fight?
Authors: Mendl M. , Erhard H.W. 
Published: June 2019

AbstractFrom an animal production and welfare perspective, an important social choice made by farm animals is whether and how vigorously to fight others. The choice to fight (i.e. simultaneous escalated aggression by both contestants) may result in severe injury when unfamiliar animals first meet or compete for highly valued resources. Game theory models of aggressive interactions predict that animals have evolved to stop or avoid fighting when they assess their chances of winning a contest to be poor. Assessment may occur during or before a fight. If it occurs before a fight, reliable cues of fighting ability must exist. If farm animals can establish relative social status by assessment prior to fighting, it may be possible to construct social groups which contain individuals of differing abilities such that most disputes are resolved through assessment and levels of damaging aggression are kept low. Social status appears to be established by assessment rather than fighting in free-ranging deer and sheep when asymmetries exist in reliable cues of their fighting abilities such as roaring rate and horn size. However, there have been few detailed studies of other farmed species and findings are equivocal. Work on young pigs suggests that, in pair-wise encounters, individuals are unable to assess weight-related asymmetries in their abilities without fighting. However, recent studies of groups of pigs suggest that some form of assessment prior to fighting may occur. Individuals were classified as high (H) or low (L) aggressive on the basis of their behaviour in an attack latency test. When litters of H pigs were mixed with litters of L pigs, significantly fewer pairs of unfamiliar pigs fought than when newly mixed groups were made up of litters of H pigs only, or litters of L pigs only. Thus, fighting was least frequent when there was a marked asymmetry in the aggressiveness of unfamiliar individuals. Another study raised the possibility that H and L pigs may be following alternative strategies which, under certain circumstances, are similarly beneficial in welfare and production terms. Further work is required to substantiate these findings and to determine whether aggressiveness is a reliable cue of fighting ability and, if so, how it is manifest and assessed.
Recent changes in the status of some Clyde vertebrates
Authors: Gibson J. A. 
Published: June 2019

SynopsisThree comprehensive surveys of Clyde vertebrates have been carried out during the past twenty-five years, and this exceptional degree of investigation permits some very valid comparisons to be made. Distinct changes in status have taken place throughout all the vertebrate classes. The work of man has had the most obvious impact. This is sometimes deliberate, as in direct attempts at species protection or destruction. At other times the impact of man is indirect, with effects on food supply, on habitat, or on health. Occasionally the effects are accidental. Many status changes are easily explained under the above headings, but others are not, and some show apparently opposite changes in closely-related species. Some changes in status are very real, and indeed are sometimes quite dramatic and obvious for all to see. Others are more apparent than real, presumably arising from increased observation. A representative selection of species is discussed.
Migratory salmonids of the Estuary and Firth of Clyde
Authors: Mackay David W. , Doughty C. Ross 
Published: June 2019

SynopsisThe paper describes the salmon and sea trout stocks of the rivers entering the sea via the Estuary and Firth of the Clyde including the Rivers Clyde, Leven, the Carts, the rivers of the Ayrshire coast and those entering via the sea lochs and from the Mull of Kintyre. Particular attention is paid to the recent return of salmonids to the Rivers Clyde and Cart, which have been denied to migratory species for over a century because of pollution in the upper Clyde Estuary. The changing environmental conditions, which have made the reappearance of migratory salmonids possible, are described and the future importance of the fishery assessed.
An evaluation of forest decline based on field observations focussed on Norway spruce, Picea abies
Authors: Schulze E.-D. , Freer-Smith P. H. 
Published: June 2019

SynopsisForest decline in Europe is centred around areas where air pollution is heaviest. Although statistical relations are still debatable at the stand level, they are a basis for the discussion of mechanisms by which air pollutants affect forest health. The aetiologies of different syndromes of decline are discussed. Exposure to large concentrations of gaseous pollutants appears to have short-term rather than long-lasting effects, whereas pathogens seem to be of only secondary importance. The deposition of sulphur and nitrogen (nitrate and ammonium) pollutants has significantly modified soil chemistry and plant nutrition. In acidic low-pH soils spruce roots, instead of utilising nitrate, preferentially take up ammonium which interferes with the uptake of other cations, notably magnesium. The nitrate remaining in soil solution, as a result of the preferential uptake of ammonium, is leached together with sulphate to groundwater, accelerating soil acidification and further decreasing the calcium and/or magnesium to aluminium ratios in soil solution. Soil solution chemistry affects root development, and thus water and nutrient uptake. Canopy uptake of nitrogen, especially of ammonium, which is additional to root uptake, may occur and appears to stimulate growth inciting a nitrogen to cation imbalance with the consequential production of decline symptoms.
Larger fungi and some of earth's major catastrophies
Authors: Watling Roy 
Published: June 2019

SynopsisThe agarics fruiting in natural and anthropogenic disturbed habitats are considered. The early colonists of such environments are species either able to utilise ephemeral resources or able to move nutrients quickly from one source to another. A suite of micro-characters uniting the species concerned is given. Attention is drawn to those agarics recorded from burns in various parts of the world, and from arctic-alpine areas. The concept of a geomorphological escalator is explored.
Redevelopment of biological activity in strip-mine spoils: saprotrophic fungal assemblages of grass roots
Authors: Zak John C. 
Published: June 2019

SynopsisThe development of fungal assemblages on root-surfaces ofAgropyron trachycaulumgrowing in control, peat, fertiliser, or sewage-amended oil sand tailings was followed over a four-year period. Although the number of fungal species isolated from the root-surfaces differed significantly among the amendments, species numbers did not change significantly within treatments over the four years. The species composition of the assemblages, however, changed considerably from year to year. Species abundance distributions for fungal assemblages from the control, peat, and fertiliser amended spoil were best described by logarithmic functions. Distributions from the sewage-treated spoil were best fitted by exponential functions. Although species composition changed over time, the forms of the species abundance distributions were not altered. The observed structure and dynamic nature of fungal assemblages on root-surfaces may not be a consequence of disturbance, but may be a typical feature of such assemblages. High nutrient addition to mine spoils can result in altered species abundance patterns, and may lead to a decrease in community stability.
Short-text learning in social media: a review
Authors: Tommasel Antonela , Godoy Daniela 
Published: June 2019

AbstractSocial networks occupy a ubiquitous and pervasive place in the life of their users. The substantial amount of content generated and shared by social networking users offers new research opportunities across a wide variety of disciplines, including media and communication studies, linguistics, sociology, psychology, information and computer sciences, or education. This situation, in combination with the continuous growth of social media data, creates an imperative need for content organisation. Thus, large-scale text learning tasks in social environments arise as one of the most relevant problems in machine learning and data mining. Interestingly, social media data pose several challenges due to its sparse, high-dimensional and large-volume characteristics. This survey reviews the field of social media data learning, focusing on classification and clustering techniques, as they are two of the most frequent learning tasks. It reviews not only new techniques that have been developed to tackle the new challenges posed by short-texts, but also how traditional techniques can be adapted to overcome such challenges. Then, open issues and research opportunities for social media data learning are discussed.
Relationships between chemical and physical body composition in two lines of Large White pigs at five feeding levels
Authors: Rook A.J. , Ellis M. , Whittemore C.T. , Phillips P. 
Published: June 2019

The ARC Nutrient Requirement of Pigs (1981) has highlighted a shortage of information which would allow factorial estimates of chemical body composition to be related to physical carcase composition and commercial grading characteristics. The present study aimed to provide estimates of these relationships.Data related to weights of total carcass lean (Le), total carcass fat (TF), subcutaneous fat (SF), intermuscular fat (IF), total carcass bone (B), whole body crude protein (P), Lipid (Li), Ash (A) and Water (W) and backfat depths (P2, L2, shouTder(sh)) of 231 Newcastle selected (S) and control (C) boars.