bluuebunny/crossref_metadata_2025 huggingface dataset:
Pulsation and Mass Loss in LPVs
Authors: Bowen George H.
Published: June 2019

The large-amplitude pulsation of long-period variables, together with a number of other interacting processes and phenomena, causes a rich variety of effects on the structure and behavior of the stars. Outflowing winds result, causing extensive mass loss, with profound consequences for stellar evolution. The present status of modeling calculations for LPVs will be discussed first, with various examples. Emphasis will be given to the great importance of complex, nonlinear, time-dependent interactions between things such as the waves and atmospheric shocks that result from pulsation; non-LTE radiative transfer; non-equilibrium chemistry; the growth, changing optical properties, and dynamics of grains; and radiation pressure on both grains and molecules. I will then survey the developing implications and insights from new results and from work now in progress. Some of these concern the structure and the behavior of individual stars (e.g. determination of the pulsation mode and limiting amplitude; properties of more massive stars); some relate to the evolution of individual stars (e.g. evolution of the wind and the mass loss rate; the wind and circumstellar region during helium shell flashes; effects of the star's metallicity); and some relate to the evolution of populations of stars (e.g. the white dwarf mass distribution). All of these, and many more, offer new perspectives and new understanding concerning the character of LPVs and their role in stellar evolution.
Element Diffusion in Pulsating Variables
Authors: Guzik Joyce Ann
Published: June 2019

Can pulsation studies yield information on the operation of element diffusion in stars? Can diffusion explain unusual properties of pulsating variables? Element diffusion theory and recent research relevant to these questions will be reviewed, with emphasis on the Sun and δ Scuti stars. High-degree solar p-modes that are sensitive to helium ionization support a reduced convection zone helium abundance consistent with that expected from diffusion. Intermediate-degree p-modes can be used to probe the structure of the convection zone base and constrain possible diffusion-produced composition gradients. δ Scuti variables have shallow convection zones and relatively short diffusion timescales. Helium diffusion may explain unusual period ratios, influence period changes, and affect the amplitudes and light curve shapes of δ Scuti stars.
Higher Vibrational Modes In RR Lyrae Stars
Authors: Glasner S. A. , Buchler J. R.
Published: June 2019

A simple method for computing the full spectrum of the linear (nonadiabatic) radial modes is implemented and tested on RR Lyrae models. The growthrates of the vibrational modes display unexpected, but physically correct undulations as a function of period, with the 8th through 10th overtones almost unstable. Caution must be exercised when only a small number of meshpoints is used, or when the meshpoints are not well distributed, as some of these overtones may become unstable, clearly an artifact of the differencing. The role that such unstable high overtones can play in hydrodynamic calculations is demonstrated.
A Survey of BL Herculis-Type Models
Authors: Robert Buchler J. , Moskalik Pawel
Published: June 2019

We have studied the nonlinear behavior of several sequences of BL Herculis-type models. The question arose whether the 2:1 resonance between the fundamental mode and the second overtone would cause the same systematic variation of Fourier parameters of the pulsation cycle with period ratio P2/P0 as was seen in the classical Cepheids. We find that for the BL Her stars, the behaviour of the light-curve Fourier phases is markedly different from the Cepheid case. In particular, ϕ21 exhibits essentially a featureless, monotone increase throughout the range of P2/P0, which is in qualitative agreement with the observed trend (Petersen & Diethelm 1986). In the velocity curves, on the other hand, the 2:1 resonance is a dominant feature and the progression of the Fourier phases and the amplitude ratios is similar to those witnessed in the Cepheids. However, here the sensitivity to the stellar masses and luminosities is significantly stronger. Our results show that radial velocity observations of the BL Her stars would pinpoint the resonance and put important new constraints on the models.
X Sources in δ Scuti Stars: an Ultraviolet Study of 71 Tau
Authors: Pasinetti Fracassini L.E. , Pastori L. , De Nile F. , Poretti E. , Antonello E.
Published: June 2019

IUE observations of δ Scuti variables were planned to study the correlations between chromospheric activity and dynamics of pulsations, convection, rotation and to search for evidence of mass loss. So far we observed the following stars: ρ Pup, β Cas, o1 Eri, K2 Boo, τ Peg, 69 Tau, 71 Tau and τ Cyg. Results and discussions on our survey may be found in Pasinetti Fracassini et al. (1990) and Fracassini et al. (1991).

Ultraviolet spectroscopic data (6 LWP and 3 SWP spectra) of 71 Tau were obtained with IUE in the year 1990, spanning an interval of 5h35rn and covering about 1.5 cycles of the pulsation period. The period, derived from new photometric observations, is 4h32m with an cimplitude of 0m.028. This variable is the most intense X-ray source in the Hyades cluster according to the results of Einstein Observatory.
Recent Results on Binary Cepheids
Authors: Evans Nancy Remage
Published: June 2019

IUE observations of hot companions of Cepheids have been used to determine the temperatures of the companions. For companions on the ZAMS, the temperatures can be used to determine the luminosity of the Cepheids from the inferred absolute magnitude of the companion. The accuracy of this method is comparable to the accuracy of calibration using Cepheids in clusters. An over-tone pulsator (SU Cas) has been identified by this technique. The luminosity of the double mode pulsator Y Car agrees with that from the PLC, confirming that is a normal Population I Cepheid. The variation of the width of the instability strip (as a function of luminosity) in the HR diagram is confirmed, and overtone and double mode pulsators are shown to be near the blue edge of the instability strip. Comparison between variables and nonvariables in the HR diagram (from IUE and cluster studies) shows very little overlap. The shape of the observed instability region may be determined both by the boundary between the variables and nonvariables and also the location of the tips of the blue loops of evolutionary tracks. Finally, eight Cepheids with hot companions which are evolved beyond the ZAMS have been studied. Half the systems are matched well by evolutionary tracks with little or no core convective overshoot near the main sequence. At least two and possibly four systems, however, cannot be matched by current isochrones.
Interstellar Grains in Reflection Nebulae
Authors: Vanysek Vladimir
Published: June 2019

Reflection Nebulae are suitable objects for studying the physical nature of interstellar grains. Unfortunately, there exist only a few sufficiently bright objects, the most widely studied being nebula NGC 7023. This nebula has been studied photographically and photoelectrically by many authors, and therefore it is best suited for the verification of some theoretical conclusions. Earlier measurements (refs. 1 to 3) have already shown unambiguously that almost all nebulae exhibit a negative color excess in comparison with the color of the illuminating star. This fact has been verified photoelectrically in reference 4. In the B – V system the average difference between the color of the star and that of a nebula is – 0.2m. These facts have been known for a long time, but the distribution of the color excess in the nebula itself has not been studied very intensively.
A Two-Dimensional White-Light Amplitude Interferometer
Authors: Breckinridge James B.
Published: June 2019

A review of the applications of a point-symmetric, 180-degree, rotational shearing interferometer is given. Material includes, photographs of the Michelson stellar interferometer fringes from α Lyr, measures of amplitude of phase excursions in the atmosphere, and a measure of the order of interference in speckle patterns. New material includes unpublished double star speckle patterns to illustrate the isoplanatic patch, a measure of the time fluctuations of the earths' atmosphere, and measurements of the properties of a 256 channel linear reticon.
The X-Ray Opacity of the Interstellar Medium
Authors: Ride S.K. , Walker A.B.C.
Published: June 2019

In order to interpret soft X-ray spectra of cosmic X-ray sources, it is necessary to know the photoabsorption cross-section of the intervening interstellar material. Current models suggest that the interstellar medium contains two phases which make a substantial contribution to the X-ray opacity: cool, relatively dense clouds that exist in pressure equilibrium with hot, tenuous intercloud regions. We have computed the soft X-ray photoabsorption cross-section of each of these two phases. The calculations are based on a model of the interstellar medium which includes chemical evolution of the galaxy, the formation of molecules and grains, and the ionization structure of each phase.
Spatially Resolved Observations of Solar Active Regions in Soft X-Rays and Centimetric Wavelengths
Authors: Pallavicini R. , Tofani G. , Vaiana G.S.
Published: June 2019

Soft X-ray images of solar active regions obtained by the S-054 experiment on Skylab have been compared with simultaneous interferometric observations at 2.8 cm. The radio data consist of one-dimensional scans with a spatial resolution of 16 arcseconds in the East-West direction. The resolution, although lower than the X-ray telescope resolution, is high enough for a detailed comparison.

We have found that there is a general correspondence in position and size between X-ray and radio sources, but relevant differences are also present. In particular, very bright, narrow components at 2.8 cm appear coaligned with regions of very weak X-ray emission. These strong radio components appear to be localized directly above sunspot umbrae.

Models of active regions are investigated both for the atmosphere directly over the sunspot umbra and for regions above the adjacent plage. The presence of the magnetic field is taken into account and its effects on the energy dissipation and on propagation of radio waves are discussed.
Theoretical Methods of Treating Line Formation Problems in Steady-State Extended Atmospheres
Authors: Rybicki George B.
Published: June 2019

Theoretical methods applicable to the study of line formation in steady-state extended atmospheres are reviewed. The formal solution of the transfer equation is considered, as well as numerical and analytical methods of determining the source function. Topics discussed include: the local frequency transformation, geometrical effects, and the case of large velocity gradients. A new plane-parallel approximation for spherically symmetric moving atmospheres is given that takes account of transverse velocity gradients.
Resonant Scattering and Recombination in CAL 87
Authors: Greiner J. , Iyudin A. , Jimenez-Garate M. , Burwitz V. , Schwarz R. , DiStefano R. , Schulz N.
Published: June 2019

The eclipsing supersoft X-ray binary CAL 87 has been observed with Chandra on August 13/14, 2001 for nearly 100 ksec, covering two full orbital cycles and three eclipses. The shape of the eclipse light curve derived from the zeroth-order photons indicates that the size of the X-ray emission region is about 1.5 R⊙. The ACIS/LETG spectrum is completely dominated by emission lines without any noticeable continuum. The brightest emission lines are significantly redshifted and double-peaked, suggestive of emanating in a 2000 km/s wind. We model the X-ray spectrum by a mixture of recombination and resonant scattering. This allows us to deduce the temperature and luminosity of the ionizing source to be kT ~ 50 — 100 eV and Lx ~ 5 x 1037 erg/s.
Jets from Accreting White Dwarfs
Authors: Sokoloski J. L. , Kenyon S. J. , Brocksopp C. , Kaiser C. R. , Kellogg E. M.
Published: June 2019

Collimated outflows from accreting white dwarfs have a vital role to play in the study of astrophysical jets.
A Chandra Survey of the ‘Bar’ Region of the SMC
Authors: Zezas A. , McDowell J. C. , Taylor P. , Kalogera V. , Fabbiano G. , Hadzidimitrion D.
Published: June 2019

We present the first results from a Chandra survey of the central region of the Small Magellanic Cloud. We detect a total of 122 sources down to a limiting luminosity of ~4.3 x 1033erg s–1, including 4 pulsars, 5 SNRs and two new transient sources. We also identify 18 more transient candidates based on comparison with ROSAT and ASCA surveys.
Revealing the Physical Changes Taking Place in Z-Track Motion in Low Mass X-Ray Binaries
Authors: Bałucińska-Church M. , Church M. J. , Halai G. , Szostek A.
Published: June 2019

The explanation of the strong physical changes clearly taking place in the Z-track class of Low Mass X-ray Binaries has so far not been obtained, and this remains a significant astrophysical problem, without which we cannot claim to understand accretion in LMXB. We have for the first time applied the Birmingham emission model (2,3) to this problem to attempt to obtain a solution from the spectral evolution along the Z-track in the source GX 340+0 observed with Rossi- ХTE. In this model, X-ray emission consists of blackbody from the neutron star, plus Comptonized emission from an extended ADC.
Multiwavelength Variability in the Symbiotic Nova V1016 CYG
Authors: Parimucha Š. , Vańko M.
Published: June 2019

Analysis of the optical and infrared photometry together with UV spectroscopy led to discovery of the 15-years periodicity in the symbiotic system V1016 Cyg. This period could be interpreted as a orbital period in the binary system consisting of the Mira variable and the hot white dwarf.

We have analyzed long-term optical photographic and UBV photoelectric photometry of V1016 Cyg. Collected observations cover pre- and post-outburst stages of the system. The light, curve suggests four stages of activity: the pre-out burst flare in 1949, the main nova-like outburst in 1904, and two post-outbursts, decreasing-amplitude flares in 1980 and 1994, respectively. Activity episodes affecting the system repeat with an interval of ~ 15 years. The ephemeris for the activity maxima is (see Parimucha et al., 2000).
SDSS J1240-01: A New AM CVn Candidate from the Sloan Digital Sky Survey
Authors: Roelofs G. H. A. , Groot P. J. , Steeghs D. , Nelemans G.
Published: June 2019

A better understanding of the AM CVn population is crucial to constrain their candidacy as SN Ia progenitors, to test binary evolution (in particular the common-envelope phase), and to predict their observable gravitational radiation signature. An AM CVn dedicated search in the Sloan Digital Sky Survey-DRl resulted in the discovery of SDSS J124058.03-015919.2, a new AM CVn candidate previously identified as a DB white dwarf in the 2dF quasar survey.
Optical Search for High Meteors in Hyperbolic Orbits
Authors: Woodworth S.C. , Hawkes R.L.
Published: June 2019

Dual-station image intensified television studies have indicated very few meteors at heights greater than 120 km, and few statistically significant hyperbolic orbits. However, the optimum intersection height for these studies was about 95 km, and the relatively small fields of view resulted in a bias against high (and therefore fast) meteors. We have developed height sensitivity correction factors, and found that short baseline television studies resulted in relatively little bias against high meteors, and the absence of meteors above 120 km appears to be real. We report preliminary results from a three-station, image-intensified video meteor detection system sensitive to apparent magnitude about +9.5 with optimum intersection heights 115-125 km. We have detected neither particularly high meteors nor meteors in clearly hyperbolic orbits. We conclude that the proportion of true hyperbolic meteors in the mass range 10-4 to 10-6 kg is less than a few percent, and that optical meteors corresponding to meteoroids in this mass range do not ablate at heights above approximately 120 km. We suggest several ways to reconcile these results with southern hemisphere radar studies.
Space Debris
Authors: Kessler D.J. , Anz-Meador P.D. , Matney M.J.
Published: June 2019

Man-made, artificial space debris is of interest to the study of interplanetary dust for two reasons: (1) In many regions of Earth orbital space, the space debris flux is larger than the natural meteoroid flux, complicating the study of interplanetary dust, and (2) models and experiments developed to understand space debris may have application to the study of interplanetary dust. The purpose of this paper is to summarize the space debris environment as it is understood today by characterizing the models used to predict the space debris environment and describing the measurements to test the model predictions.

Within the last 5 years, the space debris environment has been measured by a number of experiments. These experiments have revealed significant sources of debris in addition to the assumed major source of satellite explosions. Understanding these sources has required the development of more complex models and additional insight into the design and operation of spacecraft. Increased awareness of space debris issues at an international level has led to measures that have reduced the rate of growth in the environment. However, the number of new debris sources discovered seems to be proportional to the number of new measurements of the environment.
Empirical Scaling Laws for Crater Dimensions for Impacts into Solar Cells
Authors: Paul K. G. , Berthoud L.
Published: June 2019

The returned solar cells from the European Retrievable Carrier (EURECA) satellite and one Hubble Space Telescope Solar Array (HST-SA) acted as collector surfaces for microparticles in the vicinity of the Earth. Because only limited information on cratering formulae for solar cells was available from the literature, hypervelocity impact experiments on such samples were performed at the plasma drag accelerator facility of the Fachgebiet Raumfahrttechnik (LRT), TU München. The results from these experiments were combined with data from experiments performed during the Apollo program into a new scaling law relating particle parameters and impact crater dimensions on solar cell targets.
Accuracy of a Velocity/Trajectory Sensor for Charged Dust Particles
Authors: Auer Siegfried
Published: June 2019

A VELOCITY/TRAJECTORY cosmic dust sensor of the CHARGE-SENSING type was tested at the Heidelberg dust accelerator facility, using micronsized particles. The full-scale (0.4m x 0.4m x 0.3m) model displayed capabilities for providing accuracies to 0.1% in speed and 0.1° in angle relative to the spacecraft at high signal-to-noise (SNR) ratios. The particle's trajectory within the sensor can be located with an accuracy of 0.3mm.
Collection and Microanalysis of Antarctic Micrometeorites
Authors: Maurette M. , Engrand C. , Kurat G.
Published: June 2019

Micrometeorites (MMs) represent the most common interplanetary dust particles (50-500 μm). They are similar to carbonaceous chondrites (CCs) but do not match, mineralogically and chemically, known CC types.
A Comprehensive Study of Major, Minor, and Light Element Abundances in Over 100 Interplanetary Dust Particles
Authors: Thomas Kathie L. , Keller Lindsay P. , McKay David S.
Published: June 2019

Over 100 individual and cluster interplanetary dust particles (IDPs) have been analyzed for bulk abundances of 15 elements (C, O, Na, Mg, Al, Si, P, S, K, Ca, Ti, Cr, Mn, Fe, Ni). In general, IDPs have chondritic major element abundances, within a factor of 2 of the CI chondrites, and have carbon contents which average ~2-3 times higher than that of the most primitive, carbon-rich, carbonaceous meteorites (CI). The C-rich material is largely amorphous and is distributed throughout the particle as a matrix surrounding individual grains. The carbonaceous material has either smooth or vesicular texture; the latter texture suggests that volatiles could have been lost by particle heating which occurs during entry through the Earth's atmosphere.
The Abundance Pattern of Elements Having Low Nebular Condensation Temperatures in Interplanetary Dust Particles: Evidence for a New Chemical Type of Chondritic Material
Authors: Flynn G. J. , Bajt S. , Sutton S. R. , Zolensky M. E. , Thomas K. L. , Keller L. P
Published: June 2019

The abundances of Ni, Fe, Cr, Mn, P, Cu, K, Na, Ga, Ge, Se, Zn, S, Br, and C were measured in interplanetary dust particles (IDPs) collected from the Earth's stratosphere. All elements with nebular condensation temperatures lower than Mn, except S, were enriched relative to the most volatile-rich type of meteorite while the refractory elements Cr and Ni were present at chondritic abundances. This element abundance pattern is consistent with nebular condensation, suggesting the IDPs condensed at either a different location or time in the evolving solar nebula than do the meteorites. The enrichments of the major elements C, Na, P, and K exclude the possibility that the volatile enrichment in IDPs results from a minor amount of contamination.
Infrared Spectroscopic Observations of Neutral Helium During the 1994 Eclipse
Authors: Mann I. , Kuhn J. R. , Penn M. J.
Published: June 2019

We present the detection of a neutral helium line in observations of the solar corona obtained during the 1994 eclipse, and show that a coronal excitation process is unlikely to cause such a significant Hel emission that extends out to a distance of 3 solar radii (R⊙) from the center of the sun. Besides the scattered light of a solar prominence, as well as components of geocoronal helium, the observed emission line may come from the neutral helium components in the interplanetary medium. Recombination of ions on interplanetary dust particles may play a role for the formation of the neutral helium.
Applicability of A1-term Method to the Scattering by Irregularly Shaped Interplanetary Dust Grains
Authors: Okamoto Hajime
Published: June 2019

The first scattering coefficient (a1-term) in Mie theory is introduced to determine the dipole polarizability used in the discrete dipole approximation (DDA) to calculate the scattering properties of the cluster of spheres in order to improve our understanding of interplanetary dust particles. In this method, each sphere in a cluster is replaced by a single dipole. The accuracy of this method is tested for a few spheres in contact. It is confirmed that the a1-term method is superior to other types of DDA and is particularly suitable for the case when the particles are placed randomly. By using this method, it becomes possible to treat large cluster of spheres, i.e., a size parameter of the target X(≡ 2πreq/λ) ∽ 50, where req is a volume equivalent radius of the target, and λ is the wavelength of incident wave.
Voluntary food intake in the young pig
Authors: Fowler V. R. , Gill B. P.
Published: June 2019

During the 1st week of life the energy contained in the body of the average piglet increases by a factor between four and five. To achieve this increase the piglet must ingest metabolizable energy (ME) at a rate which is about four times its maintenance requirement. Well over half the ME supplied in the milk of the sow is in the form of emulsified fat. Whilst the piglet is being suckled, its intake is controlled by litter size, availability of teats and productiveness of the mammary gland. At 3 weeks of age the normal piglet requires about 7.8 MJ digestible energy to sustain a live growth rate of 280 g/day. At this stage the growth comprises about 40 g protein and about 68 g fat. This means that the required intake for a newly weaned piglet on a typical starter diet should be about 475 g/day. In practice such intakes are rarely achieved for several days, therefore weaning causes severe disruption of intake and of the growth curve and there are other factors involved including social disturbance and stress. Further problems are caused by the provision of diets which are unsuited to the physiology of the piglet's immature digestive tract. The sudden loss of the IgA component and indeed other protective factors contained in the dam's milk can be extremely serious, and the reduction in food intake is effectively a defence strategy by the piglet to cope with its new circumstances and try to maintain physiological homoeostasis. In some circumstances the use of antibacterial agents, organic acids or probiotics may be beneficial, but the approach is less reliable than careful formulation of the diet to avoid provocative ingredients such as soya-bean and rapeseed meal.
Integration of transgenes in breeding programs
Authors: Smith Charles
Published: June 2019

Conventional animal breeding is in a healthy state, with good rates of genetic change possible, and economic efficiency being continually improved in the different livestock species. New reproductive techniques offer faster rates of change, as with the use of embryo transfer in sheep and cattle breeding. It is now possible to introduce foreign DNA, transgenes, into the germ line of farm animals and this offers new opportunities in the genetic improvement of economic merit. The transgenes should be directed at traits of high economic value, and be made in elite breeding stocks to benefit from past genetic improvements. Much still needs to be learned about engineering transgenes and about the basic biochemical-physiological processes they are designed to affect. However many transgenes will be produced over the next decade, and some may be useful in animal improvement. Founder transgene individuals are unique for incorporation site, copy number and expression, and will require screening, multiplication, testing and evaluation, in both hemizygous (TO) and homozygous (TT) form, for all economic traits. For a transgene with a large useful net effect on economic merit, the most rapid genetic response will come from fixing it in the elite breeding stock. An effect of 5-10 percent in economic merit will be needed to offset the normal genetic improvement displaced. Current experience with transgenes is of very large effects on the target trait, but with deleterious effects on fitness and economic merit. Control of the level, tissue and time of expression are crucial to the practical use of transgenes. With uncertainty in the results of a transgenic program, conventional programs will have to be maintained, so extra investment will be required. Patent rights may bring extra benefits to breeders, but there are also risks if the stock prove defective. Breeding strategies and organization may also change. Despite initial problems and uncertainties, the power of the transgenic methods is so great that the development of transgenic stocks is likely to become a very important tool in genetic improvement of livestock in the future.
Feeding and milk fat production
Authors: Sutton J. D.
Published: June 2019

Decreasing the proportion of long forage in mixed diets from 400 to 100 g/kg at constant digestible energy intakes reduces milk fat content by approximately 5 g/kg for every 100 g/kg decrease in hay. This response varies widely and a safe minimum diet composition to maintain approximately 40 g fat/kg milk from Friesian cows in mid-lactation is approximately 450 g long forage/kg or 220 g acid-detergent fibre/kg dry matter. This, however, would reduce milk yields. With barley-based concentrates, milk yield increases as the proportion of hay in the diet is reduced, with the result that the reduction in the yield of fat is less than the fall in its concentration. Milk fat content is higher when ground maize, which is a slowly fermented starch source, or fodder beet or fibrous by-products replace rapidly fermented starch sources such as barley in low-roughage diets. Milk yield, however, is lower. Supplementary fats and oils generally increase milk yield but their effects on milk fat content and yield vary widely.

Increasing the intake of high-concentrate diets of fixed composition increases the yield of milk but reduces its fat content. Increasing the number of meals per 24 h reduces this milk fat depression without affecting milk yield. Thus, advice on milk fat production must take account of the level of intake, the pattern of feeding and the diet composition.

In most situations, the avoidance of low milk fat content requires control of rumen fermentation to prevent high proportions of propionic acid. However, with frequent feeding during the 24 h, high propionic acid in the rumen has less effect on milk fat. It appears that high plasma insulin concentration is the main factor reducing milk fat production.

The release of insulin is stimulated by the peaks of propionate, which are produced after large meals of concentrates but not by the steady supply of propionate associated with frequent feeding.

Available knowledge can permit wide variation in milk fat production by dietary manipulation with reasonable accuracy but the future aim should be for more direct intervention at metabolic control points.
1.1 The Physiological and Pathological Basis of Trace Element Deficiency Disease
Authors: Mills C. F.
Published: June 2019

No reliable statistics are available from which to assess the economic losses caused annually in the UK or elsewhere by trace element deficiency diseases in farm livestock. However, data such as those provided by the Veterinary Investigation Diagnosis Analysis Service or by annual FAO/WHO Reports on Animal Health clearly indicate that, in many instances, the circumstances leading to the development of trace element deficiency diseases are neither effectively recognized nor anticipated.
2.2 Genetic Variation in Trace Element Metabolism
Authors: Wiener G. , Woolliams J. A.
Published: June 2019

This paper reviews evidence showing that heredity is involved in the utilization of trace elements by animals. Underwood (1981) has stressed the importance of achieving dietary balance in the provision of minerals in animal nutrition and Howell (1983) has emphasized that although a small amount of a trace element may be essential for health a larger amount could be injurious. In these circumstances, information which can be used to meet the essential requirements for trace elements more precisely is likely to help in optimizing animal performance and avoiding risks to health and life. An understanding of the role of heredity in influencing trace element requirements is important in this context. Genetic variation in requirements also suggests the possibility that genetic solutions to trace element deficiency or toxicity problems may provide an alternative strategy to prophylaxis and other nutritional and management aids.
6.16 Some Advances in Clinical Biochemistry Relating to Trace Metals
Authors: McMurray C. H. , Blanchflower W. J. , McParland P. J. , O'Neill D. G. , Rice D. A.
Published: June 2019

The clinical signs of copper (Cu) deficiency are largely non-specific and a number of laboratory tests have been used extensively to assist in diagnosis. Among these are whole blood, plasma and serum Cu and caeruloplasmin (McMurray, 1980). However, for any marker to be useful diagnostically, it is necessary to identify any factors which can affect it. Plasma and serum Cu are not equivalent but are related by the equation:

Serum Cu (mg/l) = 11.7 + 0.66 plasma Cu (mg/l). The regression was obtained from the means of 24 groups of suckler cows and calves (> 10 animals/group). The equivalent relationship between serum and plasma caeruloplasmin is:

Serum caeruloplasmin = 0.0018

+ 0.59 plasma caeruloplasmin.

Units of caeruloplasmin are absorbance units in the phenylene diamine assay.

Thus, the range of normality will depend on the sample being used for the assay. The reduction in serum values is due to the loss of caeruloplasmin during blood clotting.
9.5 Glutaraldehyde as a Silage Additive: Effects on Fermentation and Protein Degradation in the Silo
Authors: Wilson R. F. , Jordan D. J.
Published: June 2019

During the ensiling process, even under good conditions, some of the plant proteins are broken down to soluble nitrogen compounds which are less well utilized by the ruminant. Formaldehyde, alone (Wilkins, Wilson and Woolford, 1974) or in conjunction with formic acid (Wilson and Wilkins, 1980), has been used as a silage additive to protect proteins against degradation during ensilage. Glutaraldehyde (Mangan, Jordan, West and Webb, 1980) has been suggested as an alternative due to its rapid fixing action and in this experiment it was compared with formaldehyde.
9.6 Grass Silages Ensiled with Either Formic Acid or a Lactobacillus Preparation and their Digestion by Jersey Cattle
Authors: Rooke J. A. , Brookes I. M. , Armstrong D. G.
Published: June 2019

The use of silage additives containing lactic acid bacteria and enzymes to promote a rapid homolactic type fermentation has met with some success in the United States but the little evidence available (see Burghardi, Goodrich and Meiske, 1980) suggests that, for grass silages, the value of this type of additive is limited. However, in laboratory silos, inoculation with lactic acid bacteria has been shown to be effective in reducing proteolysis (Carpintero, Henderson and McDonald, 1979).

The recent availability in the UK of a commercial product containing a lactic acid bacteria inoculum and the non-toxicity and ease of application of this product prompted this investigation, which describes the assessment of a silage prepared with this type of additive in comparison with a well characterized additive, formic acid.
Digestibility of rumen undegradable protein from 40 browse species measured by mobile nylon bag and in vitro techniques
Authors: Kaitho R. J. , Umunna N. N. , Nsahlai I. V. , Tamminga S. , van Bruchem J.
Published: June 2019

Crude protein concentration and energy value of cereal crop residues and poor quality grasses are below animal requirements during much of the year and browses have been incorporated in the feeding systems to improve the nutritional status of ruminants. Leaves and fruits of leguminous browses can be used as protein supplements for ruminants and are commonly used as foods in many agricultural systems. The new systems of protein evaluation (Agricultural and Food Research Council, 1992; Tamminga et al., 1994) partition food nitrogen into the amount degraded in the rumen and that which escapes ruminal degradation. Protein available for absorption post-ruminally is influenced by the amount of food nitrogen that is resistant to ruminal degradation plus microbial protein (Brown and Pitman, 1991). Several studies have been carried out to assess the digestibility of ruminal escape protein (Hvelplund, 1985; Frydrych, 1992), and the digestibility varies considerably across foods (Krishnamoorthy et al., 1982). Values between 0·80 and 0·85 are adopted for the true digestibility of protein from temperate foods and from microbial amino acids (van Bruchem et ah, 1989). However, no data are available on intestinal digestibility of browses although they have been recognized as good protein supplements. The mobile nylon bag (MNB) method is useful for assessing the digestibility of rumen undegradable food protein in the intestine (de Boer et ah, 1987). Since the MNB is labourious, it was desirable to assess the accuracy with which an in vitro (pepsin/pancreatin) procedure could predict results from the former. Therefore, the objective of this study was to determine apparent digestibility of browse rumen undegradable protein using MNB method and pepsin/pancreatin in vitro technique.
The cumulative gas production method to measure in vitro fermentation of concentrates
Authors: Debersaques F.M.A. , Williams B. A.
Published: June 2019

With the cumulative gas production technique (Theodorou et al., 1994), the amount of gas released as an end-product of substrate fermentation is measured at regular time intervals, as a measure of the kinetics of fermentation. CO2 is released both directly as a result of the fermentation and indirectly from the bicarbonate buffer in the medium (Beuvink and Spoelstra, 1992). This method was first described for the evaluation of fibrous materials. However, little work has been reported describing the use of cumulative gas production to evaluate concentrates. Soluble fermentable components are rapidly fermented after incubation, while the insoluble ones need to be hydrated and colonized by micro-organisms before they can be degraded (Van Milgen et al., 1993). The varying composition of substrates is one of the reasons for the different rates of gas production seen as these processes are taking place. Concentrates can differ greatly in their composition and therefore in their fermentation characteristics. Here, we describe our first trial with four individual concentrate ingredients, and mixtures of them, to determine whether the parameters from the individual ingredients can be used to predict the fermentation characteristics of the mixed foods.
EDITOR'S INTRODUCTION
Authors: Spolsky Bernard
Published: June 2019

From the beginning, public tests and examinations were instruments of policy. The Imperial Chinese examination was created to permit the emperor to replace the patronage system by which powerful lords were choosing their own candidates to be mandarins. The Jesuit schools in 17th-century France introduced a weekly testing system to allow central control of classroom teaching. In 19th-century England, Thomas Macaulay argued for employing the Chinese principle in selecting cadets for the Indian Civil Service; a similar system was later used for the British Civil Service. A primary school examination system was set up in England at the end of the 19th century to serve the same purpose of achieving quality control and accountability in public schools as was proposed for the No Child Left Behind Act (NCLB) that is being bitterly disputed in 21st-century United States. Chauncey's primary goal after World War II in developing the Scholastic Achievement Test for admission to elite U.S. universities was to replace the children of the wealthy establishment with highly qualified students who would see their role as contributing to public service.
POLITICS AND LEGISLATION IN CITIZENSHIP TESTING IN THE UNITED STATES
Authors: Kunnan Antony John
Published: June 2019

Politics and legislation have been entangled in language planning and policy in the United States since 1776. Regulations for immigration and citizenship (naturalization) have been in place since the Naturalization Act of 1790. This article examines the history of immigration and citizenship legislation that started with this act up to the more recent act of 1952, which included regulations requiring ability in English language and knowledge of history and government. It concludes with brief examinations of the old and redesigned Naturalization Tests.
THE INTERSECTION OF TEST IMPACT, VALIDATION, AND EDUCATIONAL REFORM POLICY
Authors: Chalhoub-Deville Micheline
Published: June 2019

The article addresses the intersection of policy, validity, and impact within the context of educational reform in U.S. schools, looking in particular at the No Child Left Behind (NCLB) Act (2001). The discussion makes a case that it is important to reconsider the established views regarding the responsibility of test developers and users in investigating impact given the conflated roles of developers and users under NCLB. The article also introduces the concept of social impact analysis (SIA) to argue for an expansion of the traditional conceptualization of impact research. SIA promotes a proactive rather than a reactive approach to impact, in order to inform policy formulation upfront.
Bioturbation, microbial activity and sediment properties in an estuarine ecosystem
Authors: Meadows P. S. , Tufail A.
Published: June 2019

Synopsis

Macrobenthic bioturbation and microbial activity can have major ecological effects on present day marine sediments some of which are also seen in the fossil record. The coastal and estuarine sediments in the Clyde Estuary area are described. They contain very high densities of benthic macroorganisms and microorganisms. These organisms have dramatic effects on the physical and chemical properties of sediments, and field and laboratory studies have shown that many geotechnical and geochemical properties of sediments are dictated by them. The effects can be on a microscale of a few millimetres horizontally or vertically (micro-spatial variation), or can have large scale consequences over hundreds of metres (macro-spatial variation).

Sediment stability (shear strength and critical erosion velocity), permeability and particle sedimentation are all altered by macro-invertebrate bioturbation or microbial activity, and many chemical properties such as Eh and pH may be influenced in a similar manner.

Biological activity may therefore play a major role in modifying sediment geotechnics and early sediment diagenesis. It also has direct relevance to the siting of man-made structures on the sea-bed and to sediment stability and transport in estuaries.In situseeding experiments may lead to biological control and manipulation of these most important field phenomena.
Population dynamics of seabirds in the Firth of Clyde
Authors: Monaghan P. , Zonfrillo B.
Published: June 2019

Synopsis

Marked interspecific differences in recent population trends have been recorded for seabirds breeding in the Firth of Clyde. Auk populations have remained comparatively stable, while considerable reductions have taken place in tern and kittiwake numbers. Shags, cormorants, gannets and great black-backed gulls have all increased, as have fulmars and herring gulls. The striking increases in the latter two species are considered in detail. To some extent, these population changes can be related to differences in the feeding ecology of the various seabirds; in particular the variation in the number of breeding terns is related to variation in food availability.
Growth Increments and Geochemical Variations in the Molluscan Shell
Authors: Jones Douglas S.
Published: June 2019

Perhaps the one structural feature of the molluscan shell which has historically attracted the most attention from biologists and paleobiologists alike is the banding or growth increment variation associated with so many molluscan species. Such growth patterns are often prominently displayed on the external surfaces of shells and have long been the focus of serious biological and paleontological research (see reviews by Clark, 1974; Lutz and Rhoads, 1980). The usefulness of external shell growth patterns in ecological or paleoecological contexts is limited, however, by both the inability to distinguish true periodic features from random disturbance marks and by the extreme crowding of growth lines near the margins of mature shells. In the last two decades these problems have been surmounted with the recognition of periodic growth patterns within molluscan shells. Internal shell growth patterns are known from all classes of mollusks, but those in the Bivalvia have been studied most extensively. This is a result of the relative ease with which a complete ontogenetic growth record can be obtained by sectioning a shell along the axis of maximum growth (Rhoads and Pannella, 1970). Analogous ontogenetic records are very difficult, if not impossible, to obtain from coiled or spiral shells (e.g., gastropods) using current techniques (Lutz and Rhoads, 1980). This chapter, then, aims to review the major types of internal shell growth patterns described within molluscan shells (mainly bivalves) and to discuss their origin and applications in ecology and paleoecology. Also taken up in this chapter is a brief consideration of geochemical variations (stable oxygen and carbon isotopes and trace and minor elements) within molluscan shells. Physical-chemical, environmental, and physiological influences on shell chemistry are discussed in relation to how biogeochemical variations in the shell may be used to reconstruct paleoenvironmental conditions.
Milk production of ewes rearing single and twin lambs at two times of year and associated plasma insulin, prolactin and blood metabolite concentrations
Authors: Bass J. , Doney J.M. , Rhind S.M.
Published: June 2019

While the functions of many hormones controlling milk production are known, there is little information concerning the inter-relationships between different hormones and between hormones and blood metabolites. The aim of this work was to investigate milk production, endocrine status and associated nutrient partitioning throughout lactation, in Greyface ewes rearing either single or twin lambs. Experiments were performed with ewes lambing in January and April. The seasonal differences in prolactin concentrations permits investigation of the importance of differences in concentrations of this hormone in the control of nutrient partitioning and milk production.
Effect of Shearing Pregnant Ewes on their Plasma Glucose Levels, Lamb Birth Weight and Lamb Growth Rates to 56 Days of Age
Authors: Kirk J.A. , Cooper R.A. , Chapman A.
Published: June 2019

The beneficial effects of shearing housed pregnant sheep are well recognised, but most workers have allowed ad libitum access to food. This trial was set up to investigate the effects of shearing when feed intake is restricted.
NOSCOW — A predictive model of the energy system of cows
Authors: Bruce J M , Broadbent P J , Topps J H
Published: June 2019

Energy is a major currency and resource in ecological systems. It is essential that the energy flows in such systems are understood for effective control of the production of livestock. With growing, lactating or pregnant cattle the farmer is faced with the problem of feeding to give optimum results. He needs to be able to predict the effects of feed quality, quantity and its distribution in time. Central to this problem is the prediction of how energy is used by the cow, for the competing processes of growth, lactation and pregnancy. The purpose of this paper is to introduce a deterministic model, NOSCOW, of the bioenergetic system for lactating, and pregnant, cattle. The model uses the recommendations of ARC (1980) as a base but includes the key ideas of potentials for lactation and growth. Twelve input factors are required by the model. The output is a time series with a weekly time step.
Selection indices for terminal sire beef breeds
Authors: Simm G. , Smith C. , Prescott J.H.D.
Published: June 2019

Rising living standards and an increasing awareness of the health risks of a diet high in saturated fats have led to strong consumer discrimination against animal fats. Additionally the surplusses of animal products in Europe suggest that more attention should be paid to the inputs in animal production, rather than solely increasing output. Improving the efficiency of lean meat production is therefore an important consideration in all meat animal systems. In 1976 Fowler, Bichard and Pease proposed the ‘biological indices’ lean growth rate and lean food conversion as selection criteria in pigs. These traits may be estimated as the product of growth rate (GR) or food conversion efficiency (FCE), and in vivo estimates of killing out and carcass lean proportions. However, in cattle and sheep the relatively low coefficient of variation of estimated killing out and of lean proportions, means that the biological indices are frequently dominated by GR and FCE. In such cases there may be little difference in response from selection solely on GR and FCE (Simm, 1983). The objective of the present study was to derive economic selection indices for terminal sire beef breeds, which might give appropriate economic weighting to the components of efficient lean meat production.
The use of consumer panels to measure the variability of beef from different sources
Authors: Hardham L E , Cook G L , Dilworth A W , Harrington G
Published: June 2019

The beef industry has become increasingly concerned about the eating quality of beef, and the effect this may be having on consumer demand. Much research has been carried out on beef eating quality using expert taste panels. However, it was felt that a clearer understanding of the variation in beef as prepared commercially and those factors affecting eating quality which are important in the market place, could be achieved by using consumer taste panels preparing and eating beef under normal domestic conditions.