bluuebunny/crossref_metadata_2025 huggingface dataset:
Cepheids in the Nearby Galaxy IC 1613
Authors: Antonello E. , Mantegazza L. , Fugazza D. , Bossi M. , Covino S.
Published: June 2019

A summary of the first results of a search for Cepheids in IC 1613 is reported along with a short discussion of the adopted technique, a comparison of the characteristics of Cepheid light curves in the Galaxy, Magellanic Clouds and IC 1613, and a possible application for a P–L relation derivation. First overtone Cepheids have been identified for the first time in a galaxy farther than the Magellanic Clouds.
Accurate Fourier Decomposition of Cepheid Radial Velocity Curves
Authors: Moskalik P. , Krzyt T. , Gorynya N. A. , Samus N. N.
Published: June 2019

The shapes of light curves and of radial velocity curves are two main predictions of the hydrodynamical models of Cepheids. Of the two, the velocity curves are more robust numerically and therefore, more suitable for comparison with the observations. In this report, we present accurate Fourier parameters for an extensive set of classical Cepheid velocity curves. Published radiative models reproduce the observations very well, with only small discrepancies present. We estimate the center of the ω2 = 2ω0 resonance to occur at Pr = 9.947 ± 0.051 day
Structural Properties of s-Cepheid Velocity Curves: Constraining the Location of the ω4 = 2ω1 Resonance
Authors: Kienzle F. , Pont F. , Moskalik P. , Bersier D.
Published: June 2019

The light curves of the first overtone Pop I Cepheids (s-Cepheids) show a discontinuity in their ϕ21 vs. P diagram, near P = 3.2 d. This feature, commonly attributed to the 2:1 resonance between the first and the fourth overtones (ω4 ≈ 2ω1), is not reproduced by the hydrodynamical models (Antonello & Aikawa 1995). With the goal of reexamining the resonance hypothesis, we have obtained new CORAVEL and CORALIE radial velocity curves for 17 overtone Cepheids. Together with 10 objects from Krzyt et al. (2000), the combined sample covers the whole range of overtone Cepheid periods. The velocity Fourier parameters display a strong characteristic resonant behavior. In striking contrast to photometric ones, they vary smoothly with the pulsation period and show no jump at 3.2 d. The existing radiative hydrodynamical models match very well the velocity parameters. The center of the ω4 = 2ω1 resonance is estimated to occur at Pr = 4.58 ± 0.04 d, i.e. at a period considerably longer than previously assumed (3.2 d). Five new s-Cepheids, with periods above 5 d, have been identified from the radial velocity curves morphology: V419 Cen, V659 Cen, MY Pup, GH Car and V440 Per. The data and the discussion can be found in Kienzle et al. (1999). Preprints and the data are available at: http://obswww.unige.ch/˜kienzle.
The RR Lyrae Period–Amplitude Relation
Authors: Clement Christine M.
Published: June 2019

A study of the period–amplitude relation for RR Lyrae variables in the globular clusters 47 Tucanae, NGC 6441 and M55 confirms a recent finding that the period–amplitude relation for RRab stars with ‘normal’ light curves is not a function of metal abundance. Evolutionary effects are more important.
Anomalous Pulsation of Field RR Lyrae Variables: Photometric and Spectroscopic Study of CM Leo, BS Com, and CU Com
Authors: Bragaglia A. , Clementini G. , Fabrizio L. Di , Tomaso S. Di , Merighi R. , Tosi M. , Evans I. , Sneden C. , Wilhelm R. , Smith H.
Published: June 2019

We present results on three presumed “anomalous” RRab stars: one is found to be an RRc variable, and the two others need further study.
RR Lyrae: Analysis of 100 Years of Observations
Authors: Szeidl B. , Kolláth Z.
Published: June 2019

Photometric observations of RR Lyrae obtained in the past one hundred years are reviewed and some important results are presented.
A New Look at the Blazhko Effect in RR Lyrae Stars with High-Quality Data from the MACHO Project
Authors: Kurtz D. W. , Alcock C. , Allsman R. A. , Alves D. , Axelrod T. S. , Becker A. C. , Bennett D. P. , Cook K. H. , Freeman K. C. , Griest K. , Lehner M. J. , Marshall S. L. , Minniti D. , Peterson B. A. , Pratt M. R. , Quinn P. J. , Rodgers A. W. , Stubbs C. W. , Sutherland W. , Tomaney A. , Welch D. L. ,   The MACHO CoUaboration
Published: June 2019

We present the first results of the analysis of 22 Blazhko stars. We find: 1) Blazhko RRab stars that are nearly pure amplitude modulators; 2) Blazhko RRab stars that have both amplitude and phase modulation; 3) A Blazhko RRab star that has an abrupt period change; 4) Proof of the Blazhko effect in RRc stars. Our data show the character of the amplitude and phase modulations of the light curves over the Blazhko cycles far better than has been previously possible.
Frequency Analysis of the RRc Variables of the MACHO Database for the LMC
Authors: Kovács G. , Alcock C. , Allsman R. , Alves D. , Axelrod T. , Becker A. , Bennett D. , Clement C. , Cook K. H. , Drake A. , Freeman K. , Geha M. , Griest K. , Kurtz D. W. , Lehner M. , Marshall S. , Minniti D. , Nelson C. , Peterson B. , Popowski P. , Pratt M. , Quinn P. , Rodgers A. , Rowe J. , Stubbs C. , Sutherland W. , Tomaney A. , Vandehei T. , Welch D. L. ,   The MACHO Collaboration
Published: June 2019

We present the first massive frequency analysis of the 1200 first overtone RR Lyrae stars in the Large Magellanic Cloud observed in the first 4.3 yr of the MACHO project. Besides the many new double-mode variables, we also discovered stars with closely spaced frequencies. These variables are most probably nonradial pulsators.
RR Lyrae Variables in the Globular Cluster M55. The First Evidence for Nonradial Pulsations in RR Lyr Stars
Authors: Olech A. , Kaluzny J. , Thompson I. B. , Pych W. , Krzemiński W. , Schwarzenberg-Czerny A.
Published: June 2019

We present the results of a photometric study of RR Lyrae variables in the field of the globular cluster M55. We have discovered nine new RR Lyrae stars, increasing the number of known variables in this cluster to 15 objects. Five of the newly discovered variables belong to Bailey type RRc and two to type RRab. Two background RRab stars are probable members of the Sagittarius dwarf galaxy. Fourier decomposition of the light curves was used to derive basic properties of the present sample of RR Lyrae variables. From an analysis of the RRc variables we obtain a mean mass of M = 0.53 ± 0.03 M⊙, luminosity log L = 1.75 ± 0.01 L⊙, Teff = 7193 ± 27 K, and helium abundance Y = 0.27 ± 0.01. We also derive the value of the color excess for M55 to be equal to E(B − V) = 0.11 ± 0.03. We estimate the values of the visual apparent distance moduli to be 13.65 ± 0.11 from RRab stars and 13.91 ± 0.08 from RRc stars. The light curves of three of the RRc variables exhibit changes in amplitude of over 0.1 mag on time scales of less than a week, rather short for the Blazhko effect, but with no evidence for another radial pulsational frequency. However, we do detect other periodicities which are clearly visible in the light curve after removing variations with the first overtone radial frequency. This is strong evidence for the presence of nonradial pulsations, a behavior common for 8 Scuti stars, but not yet observed among RR Lyr variables.
Blazhko Effect and Magnetic Field in RR Lyrae
Authors: Chadid M. , Gillet D. , Kolenberg K. , Aerts C.
Published: June 2019

The recent detection of a frequency splitting around the pulsation frequency and its harmonics points towards the magnetic model to explain the Blazhko effect. Here we show that it is urgent to confirm with modern observational techniques the existence of the magnetic field in RR Lyrae.
Nonlinear Pulsations of Convective Stellar Models
Authors: Buchler J. Robert
Published: June 2019

We review the numerical modeling of the nonlinear pulsations of classical variable stars with hydro-codes that include the effects of turbulent convection. Despite their simplicity these turbulent convective recipes appear to remove many of the difficulties that radiative codes faced. In particular, the numerical modeling of double mode pulsations has become possible.
Nonlinear Radiative Double-Mode Cepheid Models
Authors: Fokin A. , Kienzle F. , Burki G.
Published: June 2019

Robust double-mode pulsation has been found in several nonlinear radiative Cepheid models. This phenomenon has not been previously detected in purely radiative models.
Convection-Induced Oscillatory Thermal Modes in Red Giants: A New Type of Stellar Oscillation
Authors: Wood P. R.
Published: June 2019

A new type of oscillatory thermal mode has been found in red giant stars. The modes arise because of the interaction of stellar oscillations and convective energy transport. All the modes found are highly damped. However, it is possible that a different treatment of convection could lead to unstable modes capable of explaining the long secondary periods observed in some red giants.
The Newly-DiscoveredγDoradus Variables
Authors: Kaye Anthony B. , Handler Gerald , Krisciunas Kevin , Poretti Ennio , Zerbi Filippo M.
Published: June 2019

In this contribution we describe a new class of pulsating stars, the prototype of which is the bright, early F-type dwarf,γDoradus. These stars typically have between 1 and 5 periods ranging from 0.4 to 3 d with photometric amplitudes up to 0ṃ1 in JohnsonV. The mechanism for these observed variations is high-order, low-degree, nonradial, gravity-mode pulsation. A recent theoretical development describing a proposed driving mechanism for these new variables is discussed.
The orbital motion and impact circumstances of Comet Shoemaker-Levy 9
Authors: Chodas Paul W. , Yeomans Donald K.
Published: June 2019

Two months after the discovery of comet Shoemaker-Levy 9 came the astonishing announcement that the comet would impact Jupiter in July 1994. Computing the orbital motion of this remarkable comet presented several unusual challenges. We review the pre-impact orbit computations and impact predictions for SL9, from the preliminary orbit solutions shortly after discovery to the final set of predictions before the impacts. The final set of predicted impact times were systematically early by an average of 7 minutes, probably due to systematic errors in the reference star catalogs used in the reduction of the fragments' astrometric positions. The actual impact times were inferred from the times of observed phenomena for 16 of the impacts. Orbit solutions for the fragments were refined by using the actual impact times as additional data, and by estimating and removing measurement biases from the astrometric observations. The final orbit solutions for 21 fragments are tabulated, along with final estimates of the impact times and locations. The pre-breakup orbital history of the comet was investigated statistically, via a Monte Carlo analysis. The progenitor nucleus of SL9 was most likely captured by Jupiter around 1929 ± 9 years. Prior to capture, the comet was in a low-eccentricity, low-inclination heliocentric orbit entirely inside Jupiter's orbit, or, less likely, entirely outside. The ensemble of possible pre-capture orbits is consistent with a group of Jupiter family comets known as the quasi-Hildas.
Entry and fireball models vs. observations: What have we learned?
Authors: Mac Low Mordecai-Mark
Published: June 2019

This review attempts to give a coherent explanation of the main observations of the entry Comet Shoemaker-Levy 9 and the aftermath of the resulting explosions by using models of the tidal breakup of the comet, the entry of individual fragments into the jovian atmosphere, and the resulting fireballs and plumes. A critical review shows that the models appear reasonably well understood. The biggest theoretical uncertainties currently concern how to best tie models of the entry to models of the resulting fireballs. The key unknown before the impact was the size and kinetic energy of the comet fragments. The evidence now available includes the behavior of the chain of fragments, the luminosity of the observed visible fireballs and later infrared emission, the chemistry of the spots, and the lack of seismic waves or perturbations at the water cloud pressure level. These observations point to the fragments having diameters under a kilometer, densities of order 0.5 gem“3, and kinetic energies of order 1027 erg.
SL9 impact chemistry: Long-term photochemical evolution
Authors: Moses Julianne I.
Published: June 2019

One-dimensional photochemical models are used to provide an assessment of the chemical composition of the Shoemaker-Levy 9 impact sites soon after the impacts, and over time, as the impact-derived molecular species evolve due to photochemical processes. Photochemical model predictions are compared with the observed temporal variation of the impact-derived molecules in order to place constraints on the initial composition at the impact sites and on the amount of aerosol debris deposited in the stratosphere. The time variation of NH3, HCN, OCS, and H2S in the photochemical models roughly parallels that of the observations. S2persists too long in the photochemical models, suggesting that some of the estimated chemical rates constants and/or initial conditions(e.g., the assumed altitude distribution or abundance of S2) are incorrect. Models predict that CS and CO persist for months or years in the jovian stratosphere. Observations indicate that the model results with regard to CS are qualitatively correct (although the measured CS abundance demonstrates the need for a larger assumed initial abundance of CS in the models), but that CO appears to be more stable in the models than is indicated by observations. The reason for this discrepancy is unknown. We use model-data comparisons to learn more about the unique photochemical processes occurring after the impacts.
Jovian magnetospheric and auroral effects of the SL9 impacts
Authors: IP Wing-Huen
Published: June 2019

The collisions of comet Shoemaker-Levy 9 with Jupiter have produced many surprising auroral and magnetospheric phenomena. The energy released during the passage of the cometary dust comas through the jovian magnetosphere and at atmospheric explosion could lead to impulsive particle acceleration, enhanced radial diffusive transport, and the establishment of field-aligned current systems connecting the comet impact sites to their respective magnetic conjugate points. Some of the observed effects such as the abrupt increase of decimetric radio emission, the excitation of infraredemissions and mid-latitude auroral emission in the ultraviolet, could be interpreted within the framework of these mechanisms. Several auroral features like the X-ray outbursts and short-term variations in the UV emissions are more puzzling and require further observation of jovian auroral dynamics in these wavelength ranges in coordination with the Galileo mission.
Results and Future Uses of Heterodyne Spatial Interferometry at 11 Microns
Authors: Sutton Edmund C.
Published: June 2019

Heterodyne spatial interferometry at a wavelength of 11 microns has been used to examine properties of circumstellar dust shells. Among the objects which have been observed are several M-type supergiants and Mira variables as well as several peculiar infrared stars. These measurements provide information on the temperature and spatial distribution of dust grains. Possible future developments in heterodyne interferometry include longer baselines for higher resolution and the use of larger telescopes for greater sensitivity.
On Astrometric Applications Of The Very Long Baseline Amplitude Interferometer
Authors: Currie Douglas G.
Published: June 2019

The possible use of the Very Long Amplitude Interferometer in several programs of astrometric measurements and observations will be described. These programs include short-arc or differential astrometry, large-arc astrometry for zonal corrections in the FK-4 datalog and absolute astrometry primarily for the study of earth rotation. The basic techniques for these different applications, the relevant measurement precision and accuracy, and the related signal-to-noise ratios will be discussed. The role of the atmosphere and the critical atmospheric parameters, as they relate to the astrometric measurements, will be discussed including the atmospheric delay correction by the use of two separate wavelengths. The role of various types of ground motion i.e. seismic disturbance for the different types of astrometry will be discussed and data presented as to the possible effects. Measurements on the stability of equipment will also be included. In addition the use of a two color refractometer for site surveys and the evaluation of gravity waves in the atmosphere will be considered. The procedure for references to the vertical (which is required for earth rotation) will be considered.
The Continuous Spectrum of Hydrogen in a Low-Density Envelope
Authors: Gerola H. , Panagia N.
Published: June 2019

A progress report on theoretical work on the formation of a continuum in low-density stellar envelopes. Preliminary results are given on a comparison between the recombination case and the case for a semi-empirical approach including the effect of collisions from the ground state.
Searching Evidences for Spiral Shocks in the Quiescent Accretion Disk of U Gem
Authors: Neustroev V. V. , Chavushyan V. , Valdés J. R.
Published: June 2019

We find that the quiescent accretion disk of U Gem has a complicated structure. Along to the bright spot originating in the region of interaction between the stream and the disk particles, there are also explicit indications of spiral shocks. The Doppler map and the variations of the peak separation of the emission lines are indicative.
A New View of the Supersoft X-Ray Source Cal 87 Observed with XMM-Newton
Authors: Orio M. , Ebisawa K. , Heise J. , Hartmann W.
Published: June 2019

Cal 87 was observed with with XMM-Newton in April of 2003. The source shows a rich emission spectrum, where lines can be identified if they are red-shifted by 700-1200 km s –1. These lines seem to have been emitted in a wind from the system. The eclipse is observed to be shifted in phase by 0.03 ϕorb, where ϕorb is the phase of the optical light curve.
The effect of changes in the payment scheme on individual farmers
Authors: Warren M. E. , Amies S. J. , Robinson T. G.
Published: June 2019

The changes in the payment scheme proposed by the Milk Marketing Board from 1 April 1984 cover a number of issues relating to compositional quality, seasonality of pricing and the monthly distribution of production. Although the changes in total must be financially self-balancing on a national basis, the effect on individual farms may be significant.

A computer program has been used on the records from a number of farms to investigate the effect of the changes, separately and together, on annual and monthly income from milk. The effects on three herds were as follows.

Herd 1 was a Jersey herd that showed an overall increase in income per cow, due mainly to the higher price of protein. Herds with a high protein to lactose ratio in the milk will stand to gain from the new price of protein.

Herd 2 was a Friesian/Holstein herd with a low protein and low milk fat content in the milk. The herd was also calving seasonally and had a low output of milk during August and September. A substantial decrease in income of approximately £29 per cow was due principally to the low protein to lactose ratio but also to the low fat content and the seasonal pattern of milk production on the farm.
2.1 The Nutritional Basis for Trace Element Deficiencies in Ruminant Livestock
Authors: Suttle N. F.
Published: June 2019

The role of trace element deficiencies in the causation of clinical diseases is often questioned because of the poor correlations which are found between the trace element status of the animal or its diet and the incidence of disease. The most striking example is that relating to the copper (Cu) nutrition of sheep, in which concentrate diets containing 8 mg Cu/kg DM can cause poisoning (Hogan, Money and Blayney, 1968) while pastures containing twice as much Cu can cause a deficiency disease (swayback) to develop (Allcroft and Lewis, 1957; Alloway, 1973). Unidentified stress factors are often invoked to explain such anomalies. However, the poor relationships between nutritional status and disease incidence reflect the inadequacies of past methods of assessing the extent that a trace element is absorbed from the diet and its functional activity in the animal and the fact that requirements vary during an animal's life. The object of this paper is to re-emphasize the nutritional component of trace element disorders by looking at the quantitative and functional basis of trace element requirements, the factors which predispose animals to deficiencies and how these might be countered.
Remarks on donor support to animal production research
Authors: Ndiritu C. G.
Published: June 2019

In spite of being the home of a significant number of the world's flocks and herds, the productivity per head and per ha of the livestock sector in sub-Saharan Africa continues to be so low that the total output does not meet the domestic demand. Indeed, there is evidence that there has been little or no increase in output of animal products in this region during the 1980s. On the other hand, the human population has increased at a rate of more than 3% per annum. This has been associated with an escalating demand for food thus adding pressure on natural resources which are already threatened.

There is therefore a need for technical innovations to increase output of livestock products to at least a level of self-sufficiency. This increase must be obtained in a manner which is consistent with protection of the environment and conservation of natural resources for sustainable performance.

In this endeavour to develop technologies to support the livestock industries, developing countries of Africa are faced with inadequate resources to carry out research programmes, addressing a multiplicity of produciton problems. Towards this end, the donor countries have contributed resources including capital goods, technical assistance, operational finance for agreed projects and manpower development. However it is important that the national scientists are involved in the conceptualization, formulation and implementation of research programmes. The donor inputs are therefore expended in execution of projects generated by the local personnel. In this connexion, it is hoped that the level of support will be increased and sustained for a reasonable period to bear impact at the farm level. However it should be noted that research alone cannot bring about increase in output of meat and milk, etc. Rather the new technology from research is one of the inputs which must be mixed with other inputs to improve production.
Use of crop residues and agro-industrial by-products in ruminant production systems in developing countries
Authors: Jayasuriya M. C. N.
Published: June 2019

Ruminant production systems in developing countries could be classified into three categories: the extensive systems, systems incorporating arable cropping and systems integrated with tree cropping. Systems have evolved in response to the agro-ecological environment, the availability and type of land, nature of cropping patterns, frequency and intensity of cropping, area of uncultivated land and animal species and animal numbers.

Smallholder livestock farmers in most developing countries appear to have adopted a mixed system that incorporates the traditional extensive system and the system that combines arable cropping with livestock. Both in Africa and in Asia, livestock production is an important component of traditional agriculture, complementing arable cropping. Livestock utilize existing food resources such as communal grazing lands which are marginal for arable cropping, crop residues and agro-industrial by-products. Besides supplying meat and milk, organic manure and draft power, livestock are an investment and an insurance against crop failure.

Crop residues and agro-industrial by-products are a major source of nutrients for ruminant livestock in developing countries, especially during periods of fodder shortage. Despite the large research effort on upgrading crop residues in recent years, there has been little improvement in the utilization of crop residues in developing countries. Reasons for this are many but include, the absence of detailed production patterns of crop residues within countries, including when and where they are produced, the difficulties of transporting and storing crop residues, inappropriate technology and the near absence of extension services.

Both in the African and Asian continents, smallholder farmers who rear livestock for supplementary income are rather reluctant to change their traditional practices, when new technologies call for extra labour, time and capital, since the methods may be too demanding in relation to the benefit produced. The more likely application of any new technology will be with larger-scale operations where benefits are clearer and sufficiently large to warrant the extra efforts.
Resource requirements for draught animal power
Authors: Pearson R. A.
Published: June 2019

The place of draught animal power on farms in tropical agriculture is discussed. In some areas of the world draught animal power is traditional, in others it is a relatively new technology. There are situations which fall between the two, but when thinking about resolving technical and more particularly socio-economic constraints it is often useful to be aware of these two categories. While some of the problems encountered are universal, other problems can be more specific to a particular situation or country.

In this paper some of the issues are discussed. These include the energy requirements for work, the provision of food, particularly in ‘new’ draught animal areas, the consequences of using draught cows in traditional systems, disease treatment and two examples of country specific problems. In some cases strategies to cope with these issues are available, largely as a result of research, in others it is apparent that more information is required.
Fibrous diets for pigs
Authors: Close W. H.
Published: June 2019

This paper reviews current knowledge on the feeding of fibrous foods to pigs. It attempts to explain why fibrous foods differ in their nutritional value by defining what constitutes ‘dietary fibre’ and by discussing aspects associated with digestion, absorption, fermentation and metabolism in the gastro-intestinal tract. Fibrous diets can contribute proportionately up to 0-3 of the energy requirements of the animal, but there are significant reductions in the digestibility of all nutrients. There is a reduction in energy intake with increase in fibre intake, and this reduces both growth and food utilization efficiency; carcasses may, however, be leaner. Sows are better able to utilize fibre than weaned or growing/ fattening pigs and there may be improvements in reproduction as well as health and welfare benefits. Nutritive values can be improved by processing and deficiencies overcome by the use of synthetic and other materials. There is considerable potential to incorporate fibrous and by-product materials into feeding strategies for pigs in developing countries, with both economic and productive advantages.
Selection and breeding strategies for sustainable livestock production in developing countries, with particular reference to dairy cattle production
Authors: Peters K. J.
Published: June 2019

Breeding strategies for sustainable livestock production in developing countries are discussed with reference to breeding objectives in more uniform environments of temperate regions and to those in stressful and highly variable environments of the tropics. The relative importance of breeding objectives to be based not on single performance traits but also on fitness traits is discussed in relation to production efficiency. With particular reference to breeding strategies for dairy production the following aspects are referred to: assessment of scope for performance improvement; the rôle of local breeds in stressful environments; the need for potential assessment and options for breed improvement; the use of exotic breeds; and the need for comparative field performance test as part of improvement schemes.
Can genetics deliver?
Authors: Webb J
Published: June 2019

For the past thirty years pig genetics has enjoyed a clear message from its end–users: reduce backfat and production costs. During that period, genetics, nutrition and health have together delivered improvements of some 60% in lean growth rate and feed efficiency. To compound the recent misfortunes of the UK industry, meat is now slipping further behind everything else on the supermarket shelf in quality, uniformity, and above all predictability. The notion of quality stretches far beyond the product into responsibility for animal welfare, human nutrition and food safety.

The industry's present dilemma arises from five factors:

1.

uncertain market conditions with cyclical profitability

2.

poor communication of what constitutes good quality

3.

payment systems that no longer reflect what the market requires

4.

independent management of the different steps in the pork value chain

5.

possible effects of animal health on quality and uniformity.

Meanwhile the understanding of gene function and the ability to detect potentially useful genetic variation is gathering momentum. This paper examines the role that genetics can play in adding value, reducing risk and differentiating the product, from the perspective of a large vertically coordinated pork producer.
Environmental sustainability – legislation, policy drivers and perks
Authors: Brewer Alan
Published: June 2019

In this context, legislation to protect the environment is taken to mean that affecting water, soil and air and excludes wildlife, habitats and bio–diversity. In practice, of course, resource protection impacts on wildlife, habitats and bio–diversity as well as on human health.

Agriculture is responsible for over 70% of nitrates and over 40% of phosphates in English waters (Defra, 2002). Elevated levels of these nutrients can contribute to eutrophication of marine and freshwater and cause ecological harm. Agriculture is also responsible for around 80% of UK ammonia emissions to air, although the contribution from pig farming is about 9% (Defra 2002). This contributes to acid rain that can damage forests, lakes and rivers; and it adds nitrogen to nutrient–poor soils (e.g. heathland) that can change the type of vegetation. And each year there are many complaints to local authorities about odours from agricultural premises (Defra 2002).

There are a number of pieces of legislation that affect or will affect pig production that seek to avoid, limit or minimise emissions to the environment: these include the Nitrates Directive, Integrated Pollution Prevention and Control (IPPC) Directive (larger pig units), Water Framework Directive, Control of Pollution (Silage, Slurry and Agricultural Fuel Oil) Regulations 1991, Animal By–products Regulation, and the proposed Waste from Mines and Quarries and Agricultural Premises (England and Wales) Regulations that will implement the Waste Framework Directive for agriculture.
Effect of Formi®, feed structure and feed processing on the gut health of pigs
Authors: Kjeldsen K. , Overland M. , Blanchard P.
Published: June 2019

Attention on food safety issues in the European Union has increased the focus on Salmonella control in the pig industry. The UK, Ireland, the Netherlands and Germany are currently introducing Salmonella monitoring programmes, whereas Sweden and Denmark already have extensive Salmonella control programmes in place. Feed manufacturers and farmers have been faced with a dilemma. While pelleted feeds give superior growth rates and feed conversion over meals, ground feeds are known to promote a better gut environment, especially when it comes to reducing the levels of Salmonella in the gut. New Danish research points to a solution. By incorporating a proportion of coarsely ground material in a pellet along with Formi®, it is possible to both reduce Salmonella and optimise gut health and performance.
Animal awareness
Authors: Kendrick K. M.
Published: June 2019

The problem of demonstrating that animals are consciously aware of their environment or themselves in a similar manner to ourselves has proved to be a relatively intractable one since we have mainly been constrained to rely upon observation of an animal’s behaviour as an index of its awareness. It can usually be argued that even complex behaviours need not necessarily involve an animal being aware of either environmental cues or its response to them. Indeed, simple organisms or computers can perform complex responses to environmental cues when they are clearly not aware of them in the sense that we are ourselves. What can particularly distinguish conscious awareness from simple stimulus-response guided behaviour is the ability of an animal to experience some form of emotional response to an environmental cue or to its own actions. In this review I will summarize some of our experiments on sheep which show that the way their brains process visual and olfactory social and non-social cues from the environment is integrally related to and organized by the emotional significance of what is perceived. I will also argue that the way their brains process complex social stimuli from the environment in order to recognize individuals is very similar to ourselves although these processes are very strongly influenced by changes in their motivational state. From these observations I will maintain that sheep are almost certainly capable of conscious awareness of their environment although perhaps this awareness is mainly restricted to present events and needs with a limited capacity to reflect on the past or future.
Dietary choices assessed by pre- and post-grazing tests on rangeland vegetation
Authors: Molénat G. , Hubert D. , Lapeyronie P. , Gouy J. , Adama T.
Published: June 2019

Dietary choices of herbivores on rangeland complex vegetation are not easy to assess and give more or less biased results despite dedicated work (Holecheck et al., 1982; McInnis et al., 1983). Direct methods, such as oesophageal fistulas and direct observations can only be used in a limited range of conditions. Their negative effect on animal welfare emphasizes the need for non-injurious and nonstressful methods.
Preliminary study of the effect of micro-climatic variation on behavioural choices made by grazing sheep
Authors: Duncan A. J. , Mayes R. W. , Young S. A. , Wilson P. , Lamb C. S.
Published: June 2019

Sheep in the uplands of the United Kingdom face a series of choices as to where to graze. These choices have been shown to be influenced by the spatial distribution of nutrient supply from herbage (Duncan et al., 1994). Micro-climatic variation may also determine where animals forage, particularly in topographically complex environments found in upland areas. Wind and rain have marked effects on heat loss and hence on lower critical temperature (LCT) in sheep (Blaxter, 1977). Mount and Brown (1982) demonstrated that there were occasions during a year when sheep were below their LCT. This study assumed that data gathered from a standard meteorological station were applicable to conditions actually experienced by grazing animals and took no account of the ability of herbivores to select a more favourable micro-climate under extreme conditions (Mount and Brown, 1982). The experiment reported here was carried out to examine the extent to which microclimate influenced the distribution of grazing by sheep under windy conditions. Micro-climate was manipulated using artificial shelters.
Tonic immobility in pigs: two interpretations — coping strategies or fear
Authors: Erhard H. W. , Mendl M.
Published: June 2019

The concept of ‘coping strategies’ has received increasing attention over the last few years. Benus et al. (1991) reported two major types of strategy in rodents. These were the so-called active and passive strategies. The active strategy consists of being aggressive, forming behavioural routines and showing low responsiveness to changes in the environment, the passive strategy involves being low aggressive, flexible and responsive to changes in the environment. Hessing et al. (1993) reported similar findings in pigs. These strategies have potential implications for pig husbandry, since they may be more or less adaptive in specific farming environments.
Self-selection of analgesic drugs by broiler chickens
Authors: Danbury T. C. , Chambers J. P. , Weeks C. A. , Waterman A. E. , Kestin S. C.
Published: June 2019

A large proportion of broiler chickens suffer from lameness euphemistically called ‘leg weakness’. In a survey of commercial, intensively reared broilers, 90% had a detectable gait abnormality and 26% suffered an abnormality of sufficient severity for their welfare to be compromised (Kestin et al., 1992). It is assumed that leg weakness is painful but there is little direct evidence of this. Chickens have been shown to be able to select an adequate protein diet from a choice of two or three foods which are individually inadequate (Forbes and Shariatmadari, 1994). Broiler chickens showed a significant preference for food of the colour which was paired with ascorbic acid supplementation when the requirement for ascorbic acid was increased by heat stress (Kutlu and Forbes, 1993).
The biology of harpacticoid copepods in the meiofauna of shallow subtidal sands
Authors: Hardy B. L. S. , Barnett P. R. O.
Published: June 2019

Synopis

An account is given of the benthic harpacticoid copepods of a medium grade subtidal sand at a depth of 8–5 m (below chart datum) off the Ayrshire coast at Hunterston. It is the first account of seasonal changes in subtidal harpacticoids in the Firth of Clyde.

Most of the population is restricted to the top 1 cm layer of sand and this is considered to be related to food availability. There were considerable variations in total densities with largest numbers occurring in late June, as seawater temperatures increased rapidly towards the summer maxima.

Two species examined in detail, Asellopsis hispida and Harpacticus flexus each had one distinct period of reproduction during the year. Gravid females appeared first during the coldest months (January and February) followed by large numbers of copepodites from late April to June, culminating in large numbers of adults in June. Adult males clasped female stages only in May and June, after the main period of egg production. It is thought that viable sperm is carried by the adult females for about six to seven months, supposedly until the next period of egg production the following year. Adults of Harpacticus flexus are thought to be an important source of food for juvenile and small fish, particularly during July.
Shellfish fisheries in the Clyde Sea Area
Authors: Mason James , Fraser D. I.
Published: June 2019

Synopsis

The Clyde Sea Area has long been associated with shellfish fishing and has shared in the large expansion which has occurred during the past thirty-five years in the Scottish industry. Here, as elsewhere, the expansion has been helped by the establishment of processing facilities and in 1983 the landings of shellfish from the Clyde reached £4–5 million in value.

The sea bed and shores in the Clyde provide a wide range of habitats which is reflected in the commercially important species which are taken. They range from the fine mud in which Norway lobsters burrow, through sand in which cockles occur, and sandy gravel which is suitable for scallops and queens, to the hard ground inhabited by lobsters and the rocky shores on which periwinkles abound.

The most important shellfish in the Clyde, with annual landings valued at £3–75 million, is the Norway lobster, which is dealt with by Bailey et al. (1986). This contribution considers all the other species. The most valuable are scallops and queens, which now together exceed £400,000 p.a. in value. Periwinkles are gathered extensively on rocky shores. Squid are taken sporadically, by light trawlers and seine-netters, and occasionally, when they are especially abundant, form the basis of a directed fishery. Creel fishing for lobsters, edible crabs and velvet swimming crabs is less widespread than elsewhere round Scotland, but provides a useful income for a few boats. Mussels and cockles are gathered on a small scale, and cockle stocks in the Clyde proved especially valuable after English and Welsh stocks had been depleted by the severe winter of 1962–63. The only surviving fishery for the native oyster in Scotland is in the Clyde, in Loch Ryan, and attempts are being made to improve its production. Sea lochs in the Clyde offer conditions, particularly shelter, suitable for cultivating filterfeeding bivalve molluscs.
Reversibility of acidification: soils and surface waters
Authors: Wright Richard F. , Hauhs Michael
Published: June 2019

Synopsis

As empirical relationships between acidic deposition and its effects on soils and surface waters have become increasingly understood, the focus of attention has shifted to the reversal of acidification in response to decreased amounts of acidic deposition.

Recent decreases in acidic deposition, in both North America and parts of Europe, have initiated the reversal of acidification and the recovery of impacted ecosystems. Reversal has also been investigated in large-scale experiments with whole ecosystems. Predictive models can account for much of this empirical and experimental data, at least at the catchment scale, over periods of years.

Discrepancies between observed and predicted effects are attributable in part to the increasingly important role of nitrogen in soil and water acidification. ‘Nitrogen saturation’ threatens to offset the incipient recovery following decreases in SO2emissions. Future climate change might further exacerbate the problem by increasing the rate of mineralisation of soil organic matter and releasing stored nitrogen.
Colonisation of hair in disturbed soils
Authors: Tribe H. T.
Published: June 2019

Synopsis

Laboratory soil samples are disturbed soils which resemble the arable condition so common in the external world. They have many advantages for study of colonisation of buried substrates and activity may be monitored continuously by the use of a newly-developed automatic electrolytic respirometer. A condensed account of experiments is given in which colonisation of hair in soil samples is followed by measurement of overall metabolism and by direct microscopy.
Fossil Hexactinellida
Authors: Finks Robert M.
Published: June 2019

The structure and evolution of the hexactinellid skeleton has been conditioned by: (1) the rectangular form of the spicule (ultimately due to the square cross-section of the axial canal), and (2) the sheet-like form of the choanocyte-membrane, properly the choano-syncytium (Reiswig, 1979) as individual choanocytes with proper nuclei do not exist, which is a continuous syncytial sheet bearing outpocketings (diverticula) that correspond to the choanocyte chambers of other sponge groups. In most species the diverticula are separate, and attached to one another by syncytial filaments, but their arrangement as part of a sheet-like structure is still apparent. In a few species the choanocyte membrane becomes a labyrinth of anastomosing tubes. Accompanying these are the essential absence of mesogloea and the paucity of collagen (spongin), which results in the soft parts being essentially confined to the space occupied by the skeleton. The place of mesogloea is taken by a syncytial network of filaments which also form the dermal and gastral membranes.
Toronto, 1978—The First Paleontological Society Short Course
Authors: Yochelson Ellis L.
Published: June 2019

Because the first Paleontological Society short course covered the Mollusca, it may be appropriate to record a few words concerning that occasion and give belated thanks to those who participated. After being president of the Society, it occurred to me that most of the membership associated the Journal of Paleontology with it, but did not seriously consider the organization as a focal point for other activities. By giving a short course annually, I felt we could inform the membership on scientific matters, and also build up additional interest in society activities. The annual short courses on the various fossil groups and phyla have more than fulfilled that expectation. They tell the world that paleontology is alive and well.
Perspectives on Molluscan Phylogeny
Authors: Hickman Carole S. , Lindberg David R.
Published: June 2019

Achieving consensus on the definition of the Mollusca is fortunately not prerequisite to the exercise of taxonomic classification and phylogenetic analysis. Definitions emerge from analysis, and it is therefore germane to consider the ways in which analytic procedures and underlying assumptions may affect growth of knowledge of the Mollusca.
The effect of protein source in the concentrate on cow performance
Authors: Murphy J.J. , Gleeson P.A. , Morgan D.J.
Published: June 2019

A large number of studies have been carried out on the effect of level of crude protein in the concentrate supplement on cow performance. However, there is little information on the effect on milk output of different vegetable protein sources fed as a supplement to cows (on grass silage). This experiment was designed to compare the influence of 4 vegetable protein sources in the supplement, soyabean meal, groundnut meal, cottonseed meal and rapeseed meal on milk yield, intake and diet digestibility by cows in early lactation offered grass silage ad-libitum.
The effect of using a programmable out-of-parlour feeder for dairy cows
Authors: Gordon F. J.
Published: June 2019

The introduction of fully controlled out-of-parlour concentrate dispensers has brought new opportunities to concentrate feeding for dairy cows. While there may be a number of possible justifications for their use on an individual farm, it is likely that their effect on milk output and efficiency of concentrate use, will be a major factor when assessing their potential use. It has been argued that their ability to not only allow accurate concentrate rationing for each individual animal, based on milk yield, but also the fact that they can increase the frequency with which readily degradable materials, such as concentrates, are fed will provide nutritional benefits which will result in improved animal performance. In contrast the simple flat rate feeding approach implies a uniform feed input to all animals irrespective of stage of lactation or milk yield and also is generally operated on no more than two or three feeds over the 24 hour period. The purpose of the present study was therefore to compare two systems of concentrate feeding involving either the use of an out-of-parlour feeder, in which concentrates were allocated according to the milk yield of the individual animal, or the flat-rate approach. In view of the possibility that there could be an interaction between feeding system and total concentrate input both systems of feeding were compared at two levels of concentrate feeding.
Implants for Grass Finished Store Blackface Lambs
Authors: Waterhouse A. , McAuslan J. , Laipd R. , McClelland T. H.
Published: June 2019

The finishing of store Blackface lambs off grass is often relatively unprofitable due to low growth rates and relies heavily upon changes in seasonal price. Anabolic growth promoters offer means of increasing growth rates and thereby make a relatively large impact on profitability.

Sixty Blackface wether lambs were grazed in each of two years on grass from September until slaughter before March. Whole barley supplementation was commenced in December. Lambs were sold deadweight arid MLC carcase classified. Lambs were sold when judged to be at a standard fat cover.

Lambs were left unimplanted (U), implanted with 12 mg of Zeranol (Z) or with 15 mg of Oestradiol - 17β (O) in September.