bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical Distribution of Cepheid Periods in the SMC and LMC
Authors: Alibert Yann , Baraffe Isabelle
Published: June 2019

We have computed stellar evolutionary models for stars in a mass range characteristic of Cepheid variables for metallicities representative of the Magellanic Clouds populations. These calculations are coupled to a linear non-adiabatic stability analysis in order to get self-consistent mass-period-luminosity relationships. We construct period histograms taking into account a mass function and evolutionary time scales, and we compare them to those given by the microlensing surveys EROSl and OGLE.
Revised Empirical Formulae for the Absolute Magnitudes and Intrinsic Colors of RRab Stars
Authors: Walker A. R. , Kovács G.
Published: June 2019

The relations between the physical parameters of the RRab stars and the Fourier parameters of their light curves have been reanalyzed on the basis of new CCD data. We show that the absolute magnitude MV and the dereddened color indices (B − V)0, (V − I)0 are linear functions of the period and of the A1 Fourier amplitude of the V light curve. Due to the large datasets, we are able to test the consistency of the formulae on independent sets. The present results are in good or fair agreement with our previous studies, despite the fewer number of significant parameters entering in the revised formulae.
Variable Stars in the Fornax Dwarf Galaxy
Authors: Bersier D. , Wood Peter R.
Published: June 2019

We present the first results of a search for variable stars in the Fornax dwarf galaxy.
Fourier Coefficients of OGLE Variables
Authors: Morgan Siobahn , Simet Melanie , Bargenquast Stephanie , Dickerson Chris
Published: June 2019

Fourier coefficients for the variable stars in the OGLE survey of the Galactic Center and several globular clusters are presented. The characteristics of the RR Lyrae, δ Scuti and SX Phe stars are presented and a comparison to those observed in other studies is made. In some cases the coefficients of the stars can be used to determine distances and the physical characteristics of the variables.
AH Cam: An RR Lyr (Double Mode?) Star with Blazhko Effect
Authors: Garrido Rafael , Kim Seung-Lee , Yi Jonghyuk , Lee Bo-Won , Bossi Michele
Published: June 2019

We report here the discovery of a new frequency not belonging to the Blazhko series and suggest an interpretation based on coupling between a radial and a nonradial mode from multicolor observations.
Any Recent Progress in the Theory of Pulsating Stars?
Authors: Gautschy Alfred
Published: June 2019

To answer the topical question we survey synoptically the recent literature in pulsation theory. We restrict the topics to those which are not dealt with otherwise in this volume. We address research on roAp stars, EC 14026 variables, strange modes, luminous blue variables, pulsation-rotation coupling, and pulsations in compact objects seen from the classical, as well as the relativistic, viewpoint.
Nonlinear Survey of RRd Models
Authors: Szabó R. , Kolláth Z. , Csubry Z. , Buchler J. R.
Published: June 2019

We used our nonlinear hydrodynamical code with turbulent convection to model RR Lyrae stars. In some regime this approach produces double-mode solutions. We investigated series of models with different parameters (metallicity, luminosity, etc.). Our goal was to estimate the width of the double-mode region. The resulting tendencies can be directly compared with observational properties.
Influence of a Close Companion on the Variability of a Mira-Type Star
Authors: Rudnitskij G. M.
Published: June 2019

The effects of a low-mass companion (a planet?) revolving around a red giant at a short distance (inside its circumstellar envelope) are discussed. Calculations are given for a conical shock wave, induced by the orbital motion of the companion. Consequences for the stellar spectrum and light curve are derived, and predictions for the evolution of such a system are made.
Magnetic Oscillations in Radiative Stars
Authors: Zita E. J.
Published: June 2019

What drives acoustic modes in magnetic, radiative stars, such as the rapidly oscillating Ap (roAp) stars? We propose that oscillations in the shape of the magnetic field can drive magnetosonic waves, which are observed as p modes. The force-free atmosphere minimizes magnetic energy. If the field is strong enough, the magnetic configuration can oscillate about its equilibrium state. Initial calculations showed that the wavenumbers, frequencies, and available energy are consistent with observations of roAp stars (Zita 1997). We present the results of new calculations and proposed tests of our model. We also discuss the resultant <υ×b> dynamo, which may shed light on observations in B stars.
Delta Scuti Stars: Selected Recent Highlights
Authors: Handler G.
Published: June 2019

An overview of recent progress in the research on δ Scuti stars is given. Some intriguing results and open problems are pointed out, and some ideas for future investigations are provided.
Boundaries of the δ Scuti Instability Region
Authors: Pamyatnykh Alexei A.
Published: June 2019

With new data on stellar opacity and equation of state, we computed the theoretical blue edges of the classical instability strip in the vicinity of the main sequence. The results were compared with observational data on δ Scuti variables using various diagrams (HR, log g – log Teff, Mv – (b – y)0 and so on). An example of these diagrams is shown in Fig. 1. Detailed results can be found in Pamyatnykh (2000).
New γ Doradus Stars from the Hipparcos Mission and Geneva Photometry
Authors: Eyer Laurent , Aerts Conny
Published: June 2019

A search for new γ Dor stars was undertaken using the Hipparcos periodic variable star catalogue and the Geneva photometric database, leading to a list of 40 new candidates. We started a monitoring of the candidates which suited the observational window with the CORALIE spectrograph at the Swiss Euler Telescope for establishing a robust list of new γ Dor stars and studying line profile variations. We present here our long-term program.
The STACC 1998 Campaign on Praesepe: The Spectroscopy
Authors: Dall Thomas H.
Published: June 2019

The STACC campaign of 1998 on BN Cnc was an extensive international photometric campaign aimed at obtaining accurate frequencies of the pulsations in this star. To facilitate identification of the modes, parallel spectroscopic observations were made from six observatories around the world. I here present preliminary results from the spectroscopy made from the Nordic Optical Telescope. The accurate frequencies from the photometric campaign are used to obtain accurate amplitudes of the equivalent width variations. These results are to be used in an attempt to identify the pulsation modes in this star.
Period Variations and Binary Hypotheses of Three δ Scuti stars: CY Aqr, BS Aqr, AD CMi
Authors: Fu Jian Ning
Published: June 2019

Some new times of light maxima for three δ Scuti stars – CY Aqr, BS Aqr and AD CMi – have been determined based on new photoelectric photometry. Incorporated with the times presented in the literature, the O–C method is used to study the period variations of these stars with a newly-developed program OMC. The results reveal that for these three stars, the binary hypothesis concerning a low mass companion is reasonable in explaining the O–C diagrams.
Radial Velocity Studies of Pulsations in roAp Stars: γ Equ Revisited
Authors: Kanaan A. , Hatzes A. P. , Mkrtichian D.
Published: June 2019

We have used the 2D-Coudé spectrograph of the 2.7-m telescope at McDonald Observatory at a resolution of 60,000. We use an iodine cell which provides us with permanent wavelength reference.

γ Equ was observed for a period of approximately 6 hours. The signal to noise ratio was variable due to the presence of clouds. A typical value for the “good” spectra is 80.

The use of a large detector provides us with complete spectral coverage from 5,000 to 6,000 Å (the region where I2 lines are most visible and useful as a wavelength reference). This allowed us to expand over our previous work analyzing the pulsations of γ Equulei through the use of spectroscopy.
Looking for Trends in the Group Properties of Pulsating Subdwarf B Stars
Authors: Reed M. D. , Kawaler S. D. , Kleinman S. J.
Published: June 2019

We examine the pulsation properties for 13 members of the pulsating subdwarf B (sdBV, or EC 14026) class of stars. By looking at the pulsation structure of an entire class of stars, it may be possible to determine the various modes of pulsations (O’Brien 1998, Kleinman 1995). Unfortunately, when we examine the ensemble of pulsation periods in EC 14026 stars, we are only able to discern a simple correlation between pulsation period and gravity, and not any structure that might help with mode identification. So we can only report on the lack of structure in the pulsation periods and present some of the work underway, which we hope will identify modes in the future.
Time-Series Spectroscopy of EC 14026 Stars: Preliminary Results
Authors: O’Toole Simon J. , Teixeira Teresa C. , Bedding Timothy R. , Kjeldsen Hans
Published: June 2019

We have obtained time-series spectra for the pulsating hot subdwarf (sdB) PG1605+072. Previous time-series photometry of this star has shown maximum amplitude variations of ∼0.1 mag and at least 50 periods. The pulsator has the largest amplitude and longest periods of all the pulsating sdBs (or EC 14026 stars) discovered so far, and appears to be unusual in its class. Preliminary results of a search for velocity variations are presented here. With these variations, along with equivalent width measurements, oscillation mode identification should be possible.
Search For Cool White Dwarf Pulsators
Authors: Nitta Atsuko , Mukadam A. , Winget D. E. , Kanaan A. , Kleinman S. J. , Kepler S. O. , Montgomery M. H.
Published: June 2019

We are searching for pulsations in cool (< 6000 K) white dwarfs (WDs), hoping to apply asteroseismological techniques to improve our understanding of their structure and the physical processes inside them. This information is important as we use cool WDs to estimate the lower limit of the age of the Galactic disk. Within a spectroscopic and photometric survey of 110 cool WDs by Bergeron, Ruiz, & Legget, we find 28 candidates with appropriate effective temperatures, masses, and chemical compositions for possible pulsations in nonradial g modes with periods similar to those we observe in DAVs. So far, we have observed 4 candidates, but have found no evidence of large variation.
Tidal breakup of the nucleus of Comet Shoemaker—Levy 9
Authors: Sekanina Zdenek
Published: June 2019

The breakup of Comet Shoemaker-Levy 9 is discussed both in the context of splitting as a cometary phenomenon, comparing this object with other split comets, and as an event with its own idiosyncrasies. The physical appearance of the comet is described, features diagnostic of the nature of tidal splitting are identified, and the implications for modelling the event are spelled out. Among the emphasized issues is the problem of secondary fragmentation, which documents the comet's continuing disintegration during 1992-94 and implies that in July 1992 the parent object split tidally near Jupiter into 10-12, not 21, major fragments. Also addressed are the controversies involving models of a strengthless agglomerate versus a discrete cohesive mass and estimates for the sizes of the progenitor and its fragments.
Particles in Jupiter's atmosphere from the impacts of Comet P/Shoemaker-Levy 9
Authors: West Robert A.
Published: June 2019

The dark clouds that were easily seen in small telescopes after the comet impacts were caused by small particles which were deposited in Jupiter's stratosphere. Observations from the Hubble Space Telescope and from ground-based instruments at visible and infrared wavelengths indicate that the mean radius of the particles is in the range 0.1 to 0.3 μm, and the total volume of particles is approximately the same as that for a 1-km diameter sphere. In the dark core regions of freshly-formed impacts, the particles are distributed over a large vertical extent, between about 1 mb and 200 mb or deeper. The diffuse outlying haze is confined to the high-altitude end of the range. Such a distribution probably reflects different methods of emplacement of the debris as a function of distance from the impact. The color of the particles, and their volatility as required to make waves visible, suggest an organic material as the main constituent. These relatively volatile materials are thought to have condensed onto more refractory grains after the plume material cooled, some 30 minutes or more after impact. The most refractory materials expected to condense from an evolving fireball are Al2O3, magnesium and iron silicates, and soot, depending on the C/O ratio. A silicate spectral feature was observed, confirming that cometary material was incorporated into the grains, although silicate grains make up only 10-20% of the particle volume. After one year in Jupiter's stratosphere, the particles have spread some 20° in latitude and a significant number have sedimented into the troposphere where they are no longer visible.
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.
The Determination of Spectral Line Shapes for Hydrogenic Ions in Dense Plasmas
Authors: Lee R. W.
Published: June 2019

The task of calculating line-shapes in ultra-dense fusion type plasmas is discussed. The application of line-broadening theory to derive a consistent formulation for ionized emitters including ion dynamics, Debye shifts and perturber-ion correlations is outlined. The difficulties in extending the standard theories are explored with special emphasis given to the modifications necessary to treat the cases which occur in the experimental situations. Preliminary results will be presented.
EUV Spectroscopy of Solar Transition Zone Plasmas
Authors: Feldman U. , Doschek G.A.
Published: June 2019

High resolution solar spectra were recorded by the NRL normal incidence slit spectrograph on Skylab in the wavelength range from 1100 Å to 2000 Å. The spectral resolution is 0.06. Å and the spatial resolution at the Sun is 2“ x 60“. Several temperature and density-sensitive spectral lines occur in this wavelength region produced by ions formed in the transition zone at temperatures between ∽ 2 x 104 to ∽2 x 105 K. These lines are used to infer the electron density and plasma volumes in different solar regions, e.g., flares, surges, active regions, the quiet Sun and coronal holes. The densities in regions of activity are frequently found to be quite high (> 1011 cm–3), implying a filamentrary structure for the emitting plasma. In addition, from spectral line widths, regions of activity are frequently found to be highly turbulent. An attempt will be made to correlate non-thermal line widths with electron density enhancements.
Power Spectrum Analysis of Time Series in Positions and Intensities of Solar EUV Lines Observed with 0S0-8
Authors: Athay R. Grant , White O.R.
Published: June 2019

Several hundred hours of observing time with the University of Colorado spectrometer on 0S0-8 was devoted to rapidly repeated scans of one or two spectral lines while the instrument was pointed at a fixed location on the solar disk. These repeated line scans provide time series of line profiles at a given location on the sun from which we extract information on the line intensity, central wavelength and width. The data reported here are for the λ1816.93 and λ1817.45 lines of SiII. These lines are members of the same multiplet and have a gf ratio of 10:1. The lines were scanned with a slit or 1 x 20 arc second size projected on the sun. About half of the experiments were conducted by scanning only the 1816.93 line with a repeat time of about 15 seconds and about half included alternate scans of line λ1816.93 then λ1817.45 with a repeat time for each line of about 28 seconds.
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.
The Broadening of the Lyman Lines of the H-Like Ions Be IV to 0 VIII in a Laser Produced Plasma
Authors: Jannitti E. , Nicolosi P. , Tondello G. , Garifo L. , Malvezzia A.M.
Published: June 2019

Spectra emitted by laser produced plasmas of the light elements Be to 0 when observed with spatial resolution show the H-like Lyman lines strongly broadened and asymmetrically self-absorbed especially near the target. The first three lines, Lα, Lβ and Lγ of Be IV, B V, C VI, and the Lα of N VII and 0 VIII have been analyzed in detail. Temperature, density and plasma dimensions have been spectroscopically determined. A model for the emitting plasma that tkes into account Stark and Doppler broadening, motion Doppler shift and optical opacity has been devised that successfully explains the observed profiles. The diagnostic possibilities of such observations are discussed.
Line Formation in Multi-Dimensional Media
Authors: Jones H. P. , Skumanich A.
Published: June 2019

The 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

We 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

A 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.
A Broad Iron Line in the Chandra/HETG Spectrum of 4U 1705-44
Authors: Di Salvo T. , Iaria R. , Méndez M. , Burderi L. , Robba N. R. , Stella L. , van der Klis M.
Published: June 2019

We present preliminary results from a Chandra 30 ks observation of the atoll sourco 4U 1705 44. In particular we concentrate on the study of the iron Kα line, using the HEG spectrometer. The iron Kα line at ~ 6.6 keV is found to be intrinsically broad (FWHM ~ 1.7 keV); its width can be explained by reflection from a cold accretion disk extending down to ~ 17 km from the neutron star center or by Compton broadening in the hotter (~ 3 – 4 keV) corona.
A Comprehensive Hα Nova Survey of M81
Authors: Neill James D. , Shara Michael M. , Halbedel Elaine , Malnushenko Viktor
Published: June 2019

A spatially complete Hα survey of M81 for novae was conducted continuously over a 5 month interval using the Calypso Telescope at Kitt Peak, AZ. A raw nova rate for M81 gives 23 yr–1 which is a lower limit. Monte Carlo simulations using nova light curves and survey frame limits yield a nova rate of . Using this value and the K-band photometry for M81 from the 2MASS Large Galaxy Atlas of Jarret et al. (2003) gives a luminosity specific nova rate of .The spatial distribution of the novae follows the bulge light much better than the disk or total light according to KS tests of their radial distribution. The asymmetric nova distribution across the major axis line of M81 implies a bulge-to-disk nova ratio of > 9 and supports the idea that novae originate primarily in older stellar populations.
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.
Coronal Element Abundances of the Post-Common Envelope Binary V471 Tauri
Authors: Still Martin , Hussain Gaitee
Published: June 2019

Evolutionary calculations indicate that there should be no peculiar abundances on the companion star resulting from the common envelope epoch if accretion efficiencies are low. Indeed, we find no evidence for peculiar abundances from archival ASCA data, although uncertainties are high. We find that a single-temperature plasma model does not fit the data. Two-temperature models with decoupled elemental abundances suggest that Fe is underabundant compared to the Hyades photospheric mean. In the absence of a measurement of photospheric Ne abundance in the cluster, we find Ne is overabundant compared to the solar photospheric value. This is indicative of the inverse first ionization potential effect. Differences between coronal and photospheric abundances are believed to result from the fractionation of ionized and neutral material in the upper atmosphere of the star. Care must be taken to include this effect when inferring photospheric abundances from X-ray data (e.g., Sarna 2004).
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).
The 2003 Superoutburst of a New SU UMa-Type Dwarf Nova, GO Comae Berenices
Authors: Imada Akira , Uemura Makoto , Ishioka Ryoko , Nogami Daisaku , Kato Taichi ,   VSNET Collaboration Team
Published: June 2019

We photometrically observed the 2003 superoutburst of GO Com, which is a candidate for WZ Sge-type dwarf novae (WZ). However, the obtained light curve is atypical of both types: a plateau stage is too short for SU UMa-type dwarf novae (SU) while the amplitude of the superoutburst is too small for WZ. In order to explain this behavior, it might be taken into account that the mass accretion onto the white dwarf is efficient during quiescence.
Traditional problems of milk quality as experienced by manufacturers of milk products
Authors: Hayes M. J.
Published: June 2019

The changes in milk composition from the turn of the century to the present date are reviewed and the difficulties that the changes may have given to manufacturers are discussed. Butter manufacture is not affected by changes in milk compositional quality, although the spreadability of butter follows the seasonal changes in the hardness of milk fat. The legal requirements for the composition of cheese are set at levels that have not given any difficulty but the yield of cheese has suffered due to the progressive deterioration in the casein content of milk. There are some specific problems related to the operation of the European Economic Community milk subsidies, although these are more administrative and bureaucratic difficulties than compositional problems. It is concluded that technological advance can cope with any likely change in compositional variability, provided that legislation is not introduced to ensure the perpetuation of traditional methods.
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.
4.1 Soil Factors and Treatments affecting Trace Elements in Crops and Herbage
Authors: Burridge J. C. , Reith J. W. S. , Berrow M. L.
Published: June 2019

Despite the extensive knowledge of animals' dietary requirements for trace elements and detailed research into the uptake by plants of nutrients from the soil, it is surprising that the production of animal feedstuffs, having an appropriate trace-element content, still presents a considerable challenge to the agronomist. The present paper draws attention to some of the problems involved, using data from the many years of field-experiment research at the Macaulay Institute for Soil Research. These experiments have been largely restricted to the system of intensive agriculture prevailing in north-east Scotland, where heavily-grazed pasture and conserved herbage are the principal components of animal diets. The 6-7 year crop rotation most commonly practised includes a 3-4 year period of grass ley. The factors discussed have a wider relevance although their relative significance under conditions of low stocking rates, for instance on the rough or natural grazing on hill-land in the U.K. and other countries, will clearly be different.
5.2 Environmental Toxicity
Authors: Lloyd M. K.
Published: June 2019

In a nation intensively and widely industrialized and with a varied geology exploited by mineral workings in the past and present, farm animals are exposed to a wide variety of inorganic environmental pollutants. What is surprising is that so little loss arises overall. Often in incidents where there is harm to livestock, the risk is isolated to the vicinity of a single factory and may affect only one farm or one field. On the first occurrence, the cause and source may become clear and action can be taken to prevent recurrences and so they are self-limiting. These cases are difficult to anticipate and can only be dealt with as they arise. They include accidental discharge of a wide variety of materials to water courses, or dust contamination of pastures from adjacent works.
6.4 Experimental Reproduction of Nutritional Myopathy in Young Ruminants
Authors: Rice D. A. , Kennedy S. , McMurray C. H.
Published: June 2019

We found recently that sodium hydroxide, when used as a grain preservative, will rapidly destroy vitamin E in barley (McMurray, Blanchflower and Rice, 1980). This observation has been applied experimentally to make diets deficient in vitamin E which are already naturally deficient in selenium (Se). Such barley, when supplemented with other essential minerals and vitamins plus either soya bean protein or urea, will allow moderate growth (0.7 kg/day) when fed to young ruminants.
6.10 Cupric Oxide Needles in Hypocuprosis in Sheep
Authors: Whitelaw A.
Published: June 2019

The work of Dewey (1977), in Australia, showed that the oral administration of cupric oxide wire (CuON), in lengths of between 5-10 mm and a mean diameter of 0.5 mm, at a dosage rate of 10 g in a gelatin capsule to mature sheep, produced a steady increase in liver copper (Cu) concentrations over 16 days to levels over 1000 mg/kg DM above the initial levels. The 'needles' lodged primarily between the abomasal folds and, by 64 days, were no longer detectable. In grazing conditions, a dose of 20 g was administered to sheep. At neither dosage level were deleterious effects noted. Suttle (1981) administered 0.5 g CuON to hypocupraemic ewes maintained on a Cu-deficient diet and alleviated hypocupraemia for 111 days when the diet was supplemented with molybdenum (Mo) and sulphur (S), and 301 days when the diet was not so supplemented.
6.14 Serum Vitamin B12 Concentrations in Growing Cattle and Their Relationship with Growth Rate and Cobalt Bullet Therapy
Authors: Givens D. I. , Simpson V. R.
Published: June 2019

The interpretation of serum vitamin B12 concentrations in cattle is not well established but a value <350 ng/1 is commonly used to describe adequacy (MAFF, 1978). Three separate experiments explore this interpretation and the ability of cobalt (Co) bullets to increase serum vitamin B12 concentrations in cattle. In all cases, vitamin B12 has been measured microbiologically, using the organism L. leichmannii. In experiment 3, a number of samples were additionally analyzed using a radio isotope dilution (RID) technique.
The management and performance of sheep in the hills and uplands
Authors: Vipond J. E. , Gunn R. G.
Published: June 2019

An 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

This 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

To 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

From 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.
Behavioural responses of sheep to the sight and smell of blood
Authors: Anil M. H. , McKinstry J. L. , Sheldon O. , Spear S. , Taylor I.
Published: June 2019

The existing legislation in England and Wales (Ministry of Agriculture, Fisheries and Food, 1995) prohibits slaughter (sticking) of red meat animals within sight of others. Although this prohibition was originally designed to protect the welfare of animals, trying to get stunned animals out of sight of others can often result in signs of recovery being shown prior to, during and following sticking in commercial situations (Anil and McKinstry, 1993). The question of whether slaughter by exsanguination (sticking), or killing within sight, causes stress in other animals is a controversial issue. In regard to witnessing slaughter we have already attempted to address this question. This work produced no evidence to suggest that sheep (Anilet al., 1996) or pigs (Anilet al., 1997) were distressed. The effects of killing by mechanical means or shooting animals on witnessing conspecifics have also been studied in mice, hens and farmed deer by Bracke (1993) who concluded that no evidence of distress was evident. However, it is still widely believed that slaughter animals are sensitive to the presence of blood at abattoirs. This investigation was designed to test whether sheep would show any changes in their behaviour when exposed to the sight and smell of conspecific blood.
The effect of rumen adaptation to oxalic acid on diet choice by goats grazing a spinach/cabbage matrix
Authors: Frutos P. , Duncan A. J. , Young S. A.
Published: June 2019

Adaptation of large herbivores to secondary plant compounds found in their food plants may influence their food choice. Plants, which are potentially toxic, may initially be avoided by herbivores but, following sampling and adaptation of detoxification pathways, herbivores may be able to exploit certain toxic plants without detrimental effects. Thus, adaptation of the rumen microbial population can protect the host animal from the toxic effects of plant secondary compounds. Oxalic acid is a plant component found at high concentrations in a range of food plants, such as Beta vulgaris L, and Rumex spp., commonly consumed by ruminants. It is readily degraded in the rumen by Oxalobacter formigenes following a period of adaptation (Allison and Reddy, 1984).
Preferential choice of diets differing in protein content by pigs selected for high or low lean growth rate
Authors: Cameron N. D.
Published: June 2019

Testing several genotypes on one diet may impose nutritional constraints on growth of one or more of those genotypes. Use of a diet choice procedure may enable pigs to ‘choose’ the appropriate combination of the diets to attain the growth determined by their genotype. In an animal breeding context, the diet choice procedure offers the potential to increase the accuracy of predicting an animal’s genetic merit for performance test traits. In the few diet choice studies made with pigs heavier than 35 kg (e.g. Bradford and Gous, 1991), the animals have been of one genotype. Therefore, animals from the Edinburgh lean growth selection experiment (Cameron, 1994) provided the experimental resource to determine if between-selection line differences were enhanced by testing pigs on a diet choice procedure compared with testing on a single diet.
Effect of lameness on feeding behaviour of broilers
Authors: Weeks C. A. , Davies H. C. , Hunt P.
Published: June 2019

Leg weakness reduces the amount of time broilers spend on their feet (Weeks and Kestin, 1994). It has been shown for wild birds that the frequency of visits to a food source relate to the cost of reaching it (Kacelnik, 1984). We recently reported (Weeks and Davies, 1996) that this appeared to apply to lame broilers which fed for approximately twice as long but half as frequently as their mobile contemporaries.
Recent changes in the status of some Clyde vertebrates
Authors: Gibson J. A.
Published: June 2019

Synopsis

Three 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

Synopsis

The 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.