bluuebunny/crossref_metadata_2025_split huggingface dataset:
The future for the livestock industry after foot and mouth
Authors: Palmer M. 
Published: June 2019

The agricultural industry, particularly the livestock section, has been beset by difficulties in recent years, with the wettest year since 1776, the lowest commodity prices since the 1930's in many sectors, and by the widespread outbreak of ‘foot and mouth’ disease (F&M). This epidemic renewed fears for the future in an industry that was just beginning to see a glimmer of hope for better times ahead after many years of depression, with the OECD forecasting in early 2001 that world agricultural markets were poised for a ‘significant recovery‘.Following what with hindsight can be thought of as a ‘golden period’ in the early 1990's, things began to go really wrong in the livestock sector after the BSE crisis in 1996. The problems were exacerbated by many other ‘external economic’ pressures in the late 1990's - in particular the high value of the pound and its effect on trade and market prices, the economic problems in other parts of the world (particularly in South East Asia and the former Eastern bloc), and an oversupplied European food market (particularly for meat and dairy products). By the late 1990's these ‘macro’ pressures were affecting all livestock sectors and if things were not bad enough, the spectre of ‘disease’ was about to make matters worse, beginning with the outbreak of classical swine fever in the pig industry in 2000.The downward pressure on market prices and the monetary losses have also brought into focus the structural changes that are sorely needed throughout the livestock production, and meat processing/marketing supply chains in Britain. It has been apparent (ignoring the international situation) since the late 1980's, following the more rapid changes that have occurred in the final domestic consumer market, that these have been needed and they are now essential if the industry is to remain competitive in the 21st century.
The future of livestock production: planning for the unknown
Authors: Webster A.J.F. 
Published: June 2019

Forecasting the future is fun but futile since most forecasts are wrong. The only constructive strategy is to plan for the unknown. Therefore this talk will contain (almost) no predictions. It will simply consider how we may best cope with the shock of the new; the information explosion, the accelerating pace of change and its bewildering changes of direction. To do this we need to hold fast to a small number of big, lasting truths. I can survive on four, two of which are humanistic, two simply biological. These are:Biological systems evolve through modification by natural selection. The word ‘modification’ does not imply new creation but redesign from a relatively small range of standard parts and processes to meet changing needs.The application of reason is an effective and honest approach to the process of discovery and understanding. Almost all issues can benefit from application of the scientific method (reason challenged by experiment). However, almost all issues also contain elements that transcend science but these too are amenable to reason.Humans are sentient animals. In common with other sentient animals, we are powerfully motivated by how we feel (as distinct from what we think) and most powerfully motivated by the need to feel good. This need may be physical or spiritual. The physical need to enjoy comfort, the satisfaction of a good meal, or sex, ensures our genetic survival. The emotional need for security, or spiritual satisfaction ensures the stability of our communities, since in a stable community, discretion and goodness have survival value.All life forms have value. Moral philosophy argues that a life form such as a tree has an intrinsic value independent of its extrinsic value to us (e.g. for its beauty, utility or as a carbon sink). While I accept the concept of intrinsic value, I suggest that it is more useful to redefine the concept of extrinsic value in a less anthropocentric way (e.g. a tree has extrinsic value to a squirrel).
Halley’s Comet (Part II): Space Studies
Authors: Moroz Vassili I. 
Published: June 2019

AbstractAn international armada of spacecraft encountered Comet Halley in March 1986. The present article gives a brief overview of this unique event during which a cometary nucleus was seen as a spatially resolved object for the first time. It is a very dark body, the shape is irregular and the structure is inhomogeneous; only the sunward side is active. Many parent molecules were identified in the coma, including complicated hydrocarbons. There was also organic matter in the comet dust particles. Extensive studies were made of the complicated plasma environment of the comet.
Some Factors Affecting the Accuracy of Stellar Photometry with CCDs (And some ways of dealing with them)
Authors: Stetson Peter B. 
Published: June 2019

AbstractThere are many factors which make it difficult to relate instrumental CCD photometry to a fundamental standard system with an accuracy much better than about 1%. Here I will address only three of them: (1) infrared leaks in the filters; (2) the finite opening and closing times of mechanical shutters; and (3) changes in the air mass for long integrations. I will be approaching these subjects from the point of view of a visiting astronomer at someone else’s observatory, who gets three or four nights of observing time a year, and has only the afternoons preceding those nights to perform whatever tests can be carried out while the equipment sits on the telescope.
High Precision Crowded Field Photometry
Authors: Linde Peter 
Published: June 2019

AbstractMethods have been developed for high precision photometry in crowded stellar fields. The procedure includes the following steps:• Determination of a two-dimensional point spread function• Definition of groups of stars with mutually overlapping images• Determination of local background for each star group• Simultaneous fitting of point spread functions, one for each star in the groupThe Lund approach emphasizes interactivity. Many fundamental procedures are facilitated by the use of an optimised image display. Extensive modelling has been done to study the influence of various error sources.
ROSAT Deep Surveys
Authors: Hasinger Günther 
Published: June 2019

AbstractA series of 20 deep pointed observations with the ROSAT PSPC is discussed. 530 X-ray sources with 0.5-2 keV fluxes down to 3·10-15erg cm-2 s-1 have been discovered in 5.9 deg2. The N(>S) relation of the sources selected in the 0.5-2 keV band shows a density in excess of 200 deg-2 at the faintest fluxes and a flattening below 2·10-14erg cm-2 s-1. The average spectrum of those sources is a power law with energy index 1.2 ±0.1. The absorption column densities are consistent with the galactic HI columns. More than 50% of the 1-2 keV background has been resolved into discrete sources in the deepest field. The total background spectrum shows an emission line feature around 0.65 keV, most probably due to OVII-OVIII from a 2·106K plasma. Above ~ 1 keV the background is dominated by a power law spectrum with a normalization of 13.4 ± 0.2 keV cm-2 s-1 sr-1 keV-1 and a slope 1.2 ± 0.1, i.e. considerably steeper than the extrapolation from higher energies.
The Cosmic Microwave Background Spectrum: Theoretical Framework
Authors: Zotti G. De , Burigana C. 
Published: June 2019

AbstractPreliminary analyses of COBE/FIRAS data have already produced a spectacularly accurate determination of the microwave background spectrum for 1 cm ≤ λ ≤ 500 μm. The absence of detectable deviations from a blackbody spectrum sets strong constraints on physical conditions of the intergalactic plasma and, in particular, has ruled out the possibihty of a truly diffuse thermal bremsstrahlung origin of the X-ray background. General arguments suggest that comptonization distortions due to heating of the intergalactic medium associated with the formation of cosmic structures, with hot protogalactic winds, or with the ionizing flux from AGNs, are likely to be very small (comptonization parametery ≲, 10-4). A larger signal is expected from the integrated re-radiation from dust in external galaxies; to what extent this may conceal possible comptonization distortions depends on the maximum redshift at which galaxies contain substantial amounts of dust and on the temperature distribution of dust grains. In any case, a precise determination of either theyparameter or the background from distant galaxies requires a careful subtraction of the emission from the Milky Way.The great success of COBE strengthens the need for a parallel improvement in the accuracy of spectral measurements in the Rayleigh-Jeans region, where imprints of physical processes occurring at very early epochs (such as, e.g., the dissipation of small scale density inhomogeneities) may show up.
Planetary Rings as a Model in Cosmogony
Authors: Brahic André 
Published: June 2019

AbstractSince the beginning of the XVIIth century, rings of dispersed matter play an important role in theories accounting for the origin of the solar system and proto-planetary nebulae. Planetary rings afford a good opportunity of studying some of the accretion mechanisms which operate during the early evolution of a proto-planetary nebula. Three new planetary rings have been recently discovered. Space and ground-based observations have completely renewed our image of ring systems. Simultaneously, a wealth of theoretical and numerical models have flourished. Collisions between ring’s particles and gravitational perturbations of nearby satellites should explain most of the ring’s structures. However, important questions are still unanswered. We do not understand why the rings are so dissimilar. We do not know the ring’s origin and their stability over billions of years. Most of the ring’s complex structures, the existence of arcs, and color and optical depth variations are not explained. Confinement mechanisms, which are so important in cosmogony, seem to be at work in planetary rings today.
HIPPARCOS Data Distribution to the Community
Authors: Perryman M.A.C. 
Published: June 2019

AbstractThe Hipparcos satellite generates a considerable quantity of ‘raw’ data: approximately 1Gbit per day, or some lOOOGbits over its anticipated lifetime. The Hipparcos mission follows usual practices of having elements of the observing programme selected after an invitation for proposals to the general astronomical community, as well as a strong scientific interest in the data exploitation from amongst the individuals working within the scientific consortia related to the observing programme definition and the data analysis. However, an unusual feature of this mission is the fact that the elemental observations cannot be ‘separated out’ and distributed to the proposers or the consortia ‘principal investigators’. Instead, the data analysis teams will work towards the construction of a single, agreed-upon, catalogue containing the final astrometric and photometric star parameters.
Rotation of the Solar System Bodies
Authors: Kolaczek B. 
Published: June 2019

Solar System bodies are different. They have different sizes, from large planets to small asteroids, and shapes. They have different structure, from solid body to solid body with fluid atmosphere or core, to gaseous bodies, but all of them rotate. The Solar System is a big laboratory for studying rotation of solid and fluid bodies.Different observational methods are applied to determine the rotation of the Solar system bodies. They depend on the position of the observer and on the structure of the bodies. The most accurate methods, laser ranging to the Moon and artificial satellites and Very Long Base radio Interferometry have been applied to the determination of the rotation of the Earth and the Moon. Their accuracy is better than 0.001”, which on the surface of the Earth corresponds to about 3 cm. Radiotracking of artifical satellites have been used for Earth, Moon, Venus, Mars. In the case of Jupiter, Saturn, Uranus, Neptune and Pluto-Charon magnetic and photometric observations have been used respectively. Their accuracy is of the order of one tenth of a degree.
The Evolution of AGB Stars
Authors: Wood P.R. , Vassiliadis E. 
Published: June 2019

Computations of AGB stellar evolution which include the effects of mass loss are still relatively rare. However, in order to relate numbers of Mira variables, OH/IR stars and carbon stars to associated stellar populations, it is necessary to understand evolutionary timescales on the AGB.The dominant factors controlling very late AGB evolution are shell flashes and mass loss, and some quantitative estimate of the latter is needed for stellar evolution calculations. The favoured mechanism for the production of the large mass loss rates observed in late AGB stars such as OH/IR stars and dust-enshrouded carbon stars, which have mass loss rates up to a few times 10−5 M⊙ yr−1 (see van der Veen and Rugers 1989 for a compilation), is a dual process involving the lévitation of matter above the photosphere by large-amplitude radial pulsation followed by the formation of grains on which radiation pressure acts to drive the circumstellar material away from the star (Castor 1981; Holzer and MacGregor 1985; Hearn 1990). The studies by Wood (1979) and Bowen (1988) show that, by themselves, neither pulsation nor radiation pressure acting on grains can produce the very large mass loss rates from AGB stars.
Heating of Solar and Stellar Chromospheres and Coronae by MHD Waves
Authors: Musielak Z. E. 
Published: June 2019

Ground-based and satellite observations have shown that all late-type dwarfs possess hot outer envelopes, and that the chromospheric and coronal emissions observed from these envelopes vary significantly for a given, fixed spectral type. In addition, there is growing evidence for nonhomogeneous and locally strong magnetic fields in the atmospheres of these stars. It is obvious that any heating theory must account for these two observational constraints as well as for the mean level of heating.There are at least two general classes of models that deal with the required heating. The first class assumes that outer stellar atmospheres are heated by hydrodynamic (mainly acoustic) or magnctohydrodynamic (MHD) waves, and that these waves are generated by turbulent motions in the stellar convection zones. The second class considers dissipation of currents generated by photospheric motions as the primary source of energy. Neither observation nor theory has been able to definitively determine which one of these two general classes of models dominates in the atmospheric heating. The main aim of this paper is to briefly present recent developments in the MHD wave heating theory. The key problems that will be addressed are: where and how efficiently are MHD waves generated, and how do these waves propagate and dissipate energy?
Disease and Biosecurity
Authors: James A. D. 
Published: June 2019

There are large differences between the prices of animal products in regions with comparative advantage in livestock production and regions where production costs are higher. In particular, prices for many animal products are much higher in The European Union (EU) and The United States of America (USA) than in regions with extensive grazing areas or low-priced animal feed grains, e.g. Australia, South America and Southern Africa. These price differentials provide strong financial incentives for trade in animal products between these regions. However, trade is constrained by three main factors:
1.The perishability of many animal products, resulting in additional processing costs (e.g. freezing) which may also reduce the value of the product and higher transport costs.2.The fact that in many markets, high prices have been used as an element of agricultural support policy. These are partly maintained by levies on imported products.3.Zoosanitary restrictions to control the risk of introducing livestock and human disease agents in animal products.
DOC Transport and Export in a Dynamic Tropical Catchment
Authors: Sánchez‐Murillo R. , Romero‐Esquivel L. G. , Jiménez‐Antillón J. , Salas‐Navarro J. , Corrales‐Salazar L. , Álvarez‐Carvajal J. , Álvarez‐McInerney S. , Bonilla‐Barrantes D. , Gutiérrez‐Sibaja N. , Martínez‐Arroyo M. , Ortiz‐Apuy E. , Salgado‐Lobo J. , Villalobos‐Morales J. , Esquivel‐Hernández G. , Rojas‐Jiménez L. D. , Gómez‐Castro C. , Jiménez‐Madrigal Q. , Vargas‐Gutiérrez O. , Birkel C. 
Published: June 2019

AbstractDissolved organic carbon (DOC) transport and export from headwater forests into freshwaters in highly dynamic tropical catchments are still understudied. Here we present a DOC analysis (2017) in a pristine and small (~2.6 km2) tropical catchment of Costa Rica. Storm flows governed a rapid surface and lateral allochthonous DOC transport (62.2% of the annual DOC export). Cross‐correlation analysis of rainfall and stream discharge indicated that DOC transport occurred on average ~1.25 hr after the rainfall maxima, with large contributions of event water, ranging from 42.4±0.3% up to 98.2±0.3% of the total discharge. Carbon export flux (annual mean=6.7±0.1 g C · m‐2 · year‐1) was greater than values reported in subtropical and temperate catchments. Specific ultraviolet absorbance indicated a mixture of hydrophobic humic and hydrophilic nonhumic matter during both baseflow and storm events. Our results highlight the rapid storm‐driven DOC transport and export as well as low biogeochemical attenuation during baseflow episodes in a climate sensitive hot spot. By understanding the key factors controlling the amount of organic carbon transported to streams in dynamic tropical landscapes, better global‐ and catchment‐scale model assessments, conservation practices, and water treatment innovations can be identified.
Bed Load Sediment Transport and Morphological Evolution in a Degrading Uniform Sediment Channel Under Unsteady Flow Hydrographs
Authors: Wang Le , Cuthbertson Alan , Pender Gareth , Zhong Deyu 
Published: June 2019

AbstractFlume experiments are conducted to investigate the intrinsic links between time‐varying bed load transport properties for uniform sediments and bed surface morphology under unsteady hydrograph flows, in the absence of upstream sediment supply. These conditions are representative of regulated river reaches (e.g., downstream of a dam) that are subject to natural flood discharges or managed water releases, resulting in net degradation of the river bed. The results demonstrate that the hydrograph magnitude and unsteadiness have significant impacts on sediment transport rates and yields, as well as hysteresis patterns and yield ratios generated during the rising and falling limbs. A new hydrograph descriptor combining the influence of total water work and unsteadiness on bed load transport is shown to delineate these hysteresis patterns and yield ratios while correlating strongly with overall sediment yields. This provides an important parametric link between unsteady hydrograph flow conditions, bed load transport, and bed surface degradation under imposed zero sediment feed conditions. As such, maximum bed erosion depths and the longitudinal bed degradation profiles along the flume are strongly dependent on the magnitude of this new hydrograph descriptor. Similarly, nonequilibrium bedforms generated along the flume indicate that formative conditions for alternate bars, mixed bar/dunes, or dunes are defined reasonably well by an existing morphological model and the new hydrograph descriptor. These findings provide a new framework for improved predictive capabilities for sediment transport and morphodynamic response in regulated rivers to natural or imposed unsteady flows, while their wider application to graded sediments is also considered.
Water Mass Evolution and Circulation of the Northeastern Chukchi Sea in Summer: Implications for Nutrient Distributions
Authors: Lin Peigen , Pickart Robert S. , McRaven Leah T. , Arrigo Kevin R. , Bahr Frank , Lowry Kate E. , Stockwell Dean A. , Mordy Calvin W. 
Published: June 2019

AbstractSynoptic and historical shipboard data, spanning the period 1981–2017, are used to investigate the seasonal evolution of water masses on the northeastern Chukchi shelf and quantify the circulation patterns and their impact on nutrient distributions. We find that Alaskan coastal water extends to Barrow Canyon along the coastal pathway, with peak presence in September, while the Pacific Winter Water (WW) continually drains off the shelf through the summer. The depth‐averaged circulation under light winds is characterized by a strong Alaskan Coastal Current (ACC) and northward flow through Central Channel. A portion of the Central Channel flow recirculates anticyclonically to join the ACC, while the remainder progresses northeastward to Hanna Shoal where it bifurcates around both sides of the shoal. All of the branches converge southeast of the shoal and eventually join the ACC. The wind‐forced response has two regimes: In the coastal region the circulation depends on wind direction, while on the interior shelf the circulation is sensitive to wind stress curl. In the most common wind‐forced state—northeasterly winds and anticyclonic wind stress curl—the ACC reverses, the Central Channel flow penetrates farther north, and there is mass exchange between the interior and coastal regions. In September and October, the region southeast of Hanna Shoal is characterized by elevated amounts of WW, a shallower pycnocline, and higher concentrations of nitrate. Sustained late‐season phytoplankton growth spurred by this pooling of nutrients could result in enhanced vertical export of carbon to the seafloor, contributing to the maintenance of benthic hotspots in this region.
Effect of Mesoscale Oceanic Eddies on Extratropical Cyclogenesis: A Tracking Approach
Authors: Zhang Xingzhi , Ma Xiaohui , Wu Lixin 
Published: June 2019

AbstractOceanic eddies populated in the western boundary current regions in the midlatitude have been found to exert significant influence on atmospheric boundary layer, storm tracks, and large‐scale atmospheric circulation. However, mechanisms governing how mesoscale sea surface temperature (SST) anomalies associated with oceanic eddies affect extratropical cyclogenesis remains unclear. Here, we investigate the influence of Kuroshio oceanic eddies on cyclogenesis in the North Pacific in high resolution climate model simulations using a cyclone tracking approach. Based on cyclone tracking and composite analyses, we find that presence of mesoscale SST anomalies almost doubles water vapor supply, leading to significant increase of diabatic heating release and eddy potential energy to eddy kinetic energy conversion and thus supporting stronger storm growth rate and intensified cyclones. This finding implies that moisture process is the key linking mesoscale oceanic eddies in the western boundary current regions with storm tracks in the midlatitude.