bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of fineness of grinding of a sample on the loss of material from nylon bags incubated in the rumen of sheep
Authors: Kyle D.J. , Hovell F.D.DeB. , Bajracharya J.
Published: June 2019

The measurement of the degradability of a roughage by means of the nylon bag technique usually requires the preparation of the sample by grinding with a laboratory hammer mill. There is a wide range of screen sizes available which produce samples which range from a fine flour to coarser materials containing particles several millimeters in length. The objective of this experiment was to examine the effect of fineness of grinding on the degradation of roughages as measured by the nylon bag technique.

Samples of hay and barley straw were ground through a 1 mm screen (fine) or through a bar screen with 3-5 by 33 mm slots (coarse). Two grammes contained in nylon bags were incubated in the rumen of each of four sheep fed on a good quality roughage, giving four observations per sample. All bags were introduced into the rumen at the same time relative to feeding. Zero-time losses were determined by washing bags without incubation. Water soluble material by filtration through a Whatman No. 1 filter paper. The particle size distribution of the hay used in Expt 1 is shown by Fig 1.
The effect of level of protein in the concentrates on hay intake, milk production and digestive processes by Saanen goats
Authors: Badamana M S , Sutton J D
Published: June 2019

Increasing the crude protein (CP) concentrations of dairy concentrates in mixed diets has been found to increase milk yield and forage intake in a curvilinear manner in lactating dairy cows. In an experiment with lactating goats, linear increases in milk yield were observed as the CP in the concentrates was increased from 117 to 185 gAg DM. The purpose of the present experiment was to see if increases in hay intake and milk yield could be established to still higher levels of CP in the concentrates and to measure various associated aspects of digestion.
Gizzard erosion in broilers when high-fishmeal diets are supplemented with sodium bicarbonate
Authors: Cooper R.A. , Tembo S.L. , Hill Amanda
Published: June 2019

The problem of gizzard erosion in poultry has been linked with the presence in some fishmeal samples of a contaminant, gizzerosine, which stimulates the secretion of acid by the proventriculus. In 1985, a severe outbreak of gizzard erosion in a broiler unit in Devon was associated with the inclusion of Chilean fishmeal at 90g/kg. When the inclusion rate was reduced to 30g/kg the symptoms disappeared. This experiment used fishmeal from the same batch as that which had apparently caused gizzard erosion, and the same rates of inclusion, to examine the potential of NaHCO. to buffer the effects of increased acid secretion.
The Cathedral School of Reims in the Time of Master Alberic, 1118-1136
Authors: Williams John R.
Published: June 2019

Western Europe in the first half of the twelfth century was witnessing a great intellectual and cultural revolution. One manifestation of this was the hordes of ambitious youths seeking instruction, not only in the traditional ‘seven liberal arts,’ but also in the more specialized fields of law, medicine, and theology. In consequence, old educational centers were being revitalized and new ones were appearing. For centuries, of course, most monasteries and some cathedrals had maintained schools. Previous to the twelfth century, however, the monastic schools had played a more conspicuous role in education than those of the cathedrals. The period with which we are concerned saw a notable reversal in this situation. Usually located in rural areas, monasteries were unprepared to supply the needs of large numbers of students. Nor was the presence of a transient and turbulent body of adolescents conducive to monastic discipline. Cathedrals, on the other hand, situated in the rapidly growing towns, could supply the students in their schools with the necessities of life, while providing elementary and often advanced instruction through a corps of teachers supervised by the cathedral scholasticus. Thus the early progress of the ‘Twelfth-Century Renaissance’ can frequently be best observed in a study of the history of this or that cathedral school. In the long run Paris, Laon, and Chartres were to exert the greatest influence. Yet there were many other schools in the period, 1100-1150, which could boast a famous master or two and which produced notable scholars. One of these was Reims, which under Master Alberic enjoyed for nearly twenty years a prestige in theological studies equalled by no contemporary school.
The Carolingian Military Frontier in Italy
Authors: Drew Katherine Fischer
Published: June 2019

The Carolingians regarded much of Italy as a military frontier following their overthrow of the Lombard kingdom in 776. Although there was little national Lombard resistance to Frankish rule, other factors — which will be noted later — forced the Franks to keep up their military establishment in Italy. In some ways this military establishment followed the pattern of Carolingian arrangements in other conquered territories, in other ways the Italian situation was quite unique. Since the Carolingian failure to solve the problem of Italian unity was in at least a degree due to the Carolingian failure to meet the challenge of the Italian military frontier, the study of this problem throws some interesting light on the turbulent conditions in northern and central Italy before and after its incorporation in the German Holy Roman Empire.
Les ‘Questiones' des Canonistes (IV)
Authors: Fransen Gérard
Published: June 2019

Nous avons édité ici même, l'an dernier, les thèmes de 76 questions contenues ans deux MSS parallèles (Zwettl, Stiftsbibl. 162, fol. 123-144v [Zw] et Wien Ãionalbibl. 2163, fol. 75-85ra et 91ra-95vb [Wi]) et dont un bon nombre se trouvaient dans d'autres MSS. Nous voudrions aujourd'hui donner un premier complément à ce travail en achevant le dépouillement de deux de ces SS: Bamberg, Staatsbibl. can. 45, fol. 41-56v [Bb] et Klosterneuburg, Stiftsbibl. 656, fol. 19-33v [Kb], en notant le parallélisme avec Fulda, Landesbibl.
Pour une Histoire rurale de l'Afrique du Nord : L' « Atlas des Centuriations romaines de Tunisie ». Une question de méthode
Authors: Despois Jean
Published: June 2019

Les historiens, les archéologues et quelques géographes ont suivi avec le plus grand intérêt l'apparition progressive, par l'extension des photographies aériennes, des vestiges, encore fortement imprimés sur le sol tunisien, du cadastre romain, de ces centuriations de la fin du second siècle avant J.-C. au premier siècle après J.-C., qui ont couvert une bonne partie du pays d'un quadrillage rigoureusement géométrique de carrés de 710 mètres de côté. Deux études récemment publiées dans cette revue par MM. Caillemer et Chevallier ont tenté de faire le point de recherches qui ont fortement progressé avec l'aide des techniciens de l'Institut Géographique National.
Study of diffraction data sets using factor analysis: a new technique for comparing mineralogical and geochemical data and rapid diagnostics of the mineral composition of large collections of rock samples
Authors: Fomina Ekaterina , Kozlov Evgeniy , Ivashevskaja Svetlana
Published: June 2019

This paper presents an example of comparing geochemical and mineralogical data by means of the statistical analysis of the X-ray diffraction patterns and the chemical compositions of bulk samples. The proposed methodology was tested on samples of metasomatic rocks from two geologically different objects. Its application allows us to mathematically identify all the main, secondary and some accessory minerals, to qualitatively estimate the contents of these minerals, as well as to assess their effect on the distribution of all petrogenic and investigated trace elements in a short period of time at the earliest stages of the research. We found that the interpretation of the results is significantly influenced by the number of samples studied and the quality of diffractograms.
Focal adhesion kinase PTK2 autophosphorylation is not required for the activation of sodium–hydrogen exchange by decreased cell volume in the preimplantation mouse embryo
Authors: Fenelon Jane C. , Xu Baozeng , Baltz Jay M.
Published: June 2019

Recovery from decreased cell volume is accomplished by a regulated increase of intracellular osmolarity. The acute response is activation of inorganic ion transport into the cell, the main effector of which is the Na+/H+ exchanger NHE1. NHE1 is rapidly activated by a cell volume decrease in early embryos, but how this occurs is incompletely understood. Elucidating cell volume-regulatory mechanisms in early embryos is important, as it has been shown that their dysregulation results in preimplantation developmental arrest. The kinase JAK2 has a role in volume-mediated NHE1 activation in at least some cells, including 2-cell stage mouse embryos. However, while 2-cell embryos show partial inhibition of NHE1 when JAK2 activity is blocked, NHE1 activation in 1-cell embryos is JAK2-independent, implying a requirement for additional signalling mechanisms. As focal adhesion kinase (FAK aka PTK2) becomes phosphorylated and activated in some cell types in response to decreased cell volume, we sought to determine whether it was involved in NHE1 activation in the early mouse embryo. FAK activity requires initial autophosphorylation of a tyrosine residue, Y397. However, FAK Y397 phosphorylation levels were not increased in either 1- or 2-cell embryos after cell volume was decreased. Furthermore, the selective FAK inhibitor PF-562271 did not affect NHE1 activation at concentrations that essentially eliminated Y397 phosphorylation. Thus, autophosphorylation of FAK Y397 does not appear to be required for NHE1 activation induced by a decrease in cell volume in early mouse embryos.
Genetic impact assessments – summary of a debate
Authors: Pilling D.
Published: June 2019

Some countries have introduced a requirement for genetic impact assessments prior to granting permission for the import of new exotic livestock breeds. However, the merits of such a system are not universally accepted. During February 2007 a discussion on the subject took place on FAO's Domestic Animal Diversity Network (DAD-Net) electronic forum. This paper presents a description of how the discussion developed, and a summary of the issues raised. Arguments both for and against requiring impact assessments were put forward. Those opposing such measures focused on the risks of limiting access to animal genetic resources (AnGR), and questioned the benefits of government interference. Practical constraints to implementation and enforcement were also noted. Counter arguments pointed to the potential for avoiding the loss of valuable AnGR, and stressed governments' responsibilities to intervene where necessary to promote sustainable development, to defend the interests of the poor, or to protect national heritage. The debate ranged more widely — encompassing the respective roles of local and exotic AnGR in different regions of the world and in different production systems.
Isotopic Inferences on Early Ecosystems
Authors: Knoll Andrew H. , Canfield Donald E.
Published: June 2019

Long thought to be inaccessible to empirical inquiry, Earth's early biosphere has in recent decades become a central focus of evolutionary and paleobiological research. Knowledge of Precambrian ecosystems comes from three principal sources. The conventional fossil record consists of the compressed and permineralized remains of cyanobacteria, protists and other microorganisms (e.g., Knoll, 1996), complemented by stromatolites and oncolites, the accretionary trace fossils of microbial mat communities (Walter, 1976). Independent inferences about early evolution can be drawn from molecular phylogenies (Pace, 1997). The third principal source of information comprises biogeochemical signatures encrypted in the chemistry of ancient sedimentary rocks. Biomarker molecular fossils and distinctive isotopic compositions record the metabolic activities of organisms not necessarily preserved morphologically (Summons and Walter, 1990). In this paper, we review the inferences about early life and environments that can be drawn from the isotopic records of carbon and sulfur.
An Honors Course on Evolution and Creationism: Teaching Experiences in the Deep South
Authors: Kelley Patricia H.
Published: June 2019

One of the most stimulating and enjoyable experiences of my teaching career has been an honors course on evolution and creationism, which I developed while a faculty member at the University of Mississippi. At many institutions, honors courses provide the freedom to tackle controversial subjects, employ an interdisciplinary approach, and allow professors and students to take more risks (pedagogically and conceptually) than in non-honors courses. Honors classes tend to be smaller, encourage active learning and critical thinking on the part of students, and emphasize open discussion rather than passive note taking as the faculty member lectures. Such a format is an ideal context for a course on evolution and creationism.
Teaching Biopoesis and Evolution: Taking the Controversy Out of Controversial Topics
Authors: Gibson Michael A.
Published: June 2019

The scientific concepts of origin of life (biopoesis) and organic change through time (organic evolution) are often difficult to motivate students to learn, much less accept, because non-scientific viewpoints and emotions developed previously can overshadow scientific viewpoints, thus closing minds to learning. This leads to the formation of “entrenched camps” and introduces an adversarial atmosphere inherently antagonistic and counterproductive to learning. This is particularly true in the “Bible-belt” south, and in Tennessee where the evolution controversy has been especially visible in the political and legislative arenas. Inaccuracies and political solutions to teaching evolution at the K-12 levels have created an understanding of evolution fraught with misconceptions, incorrect definitions, and incomplete explanations. I have found that the real challenge to learning at this point is creating a non-threatening atmosphere of receptiveness.
Supporting Predators: Changes in the Global Ecosystem Inferred from Changes in Predator Diversity
Authors: Bambach Richard K.
Published: June 2019

This paper presents new estimates of the genus diversity of predators in each major taxon containing predators, as well as an estimate of the total genus diversity of predators through the Phanerozoic. Predators have never been numerically abundant compared to prey. However, the diversity of predators and the proportion of total faunal diversity composed of predators have both increased over time, implying that ecosystems have increased their ability to support either more predators or more specialization among predators. Also, turnover in diversity dominance among predator groups, with more energetic predator taxa replacing or being added to a fauna of less energetic groups, implies that the energy available in marine food webs has increased. The apparent increase in diversity and biomass of primary producers plus patterns of diversity change in prey taxa supports these inferences based on patterns of change in predators alone.
The effects of concentrate energy source on milk composition of lactating dairy cattle offered grass silage
Authors: Keady T.W.J. , Mayne C.S. , Fitzpatrick D.A.
Published: June 2019

Two partially balanced change-over design experiments were undertaken to examine the effects of concentrate energy source on milk yield and composition of lactating diary cows offered a diverse range of grass silages. A total of nine silages differing in fermentation digestibility and intake characteristics were produced in experiments 1 and 2. Silage dry matter (DM) concentration ranged from 170 to 473 g/kg, ammonia nitrogen ranged from 58 to 356 g/kg nitrogen, digestible organic matter in the DM ranged from 551 to 724 g/kg and silage DM intake potential ranged from 57 to 103.8 g/kg w0.75 respectively. In experiment 1, 5 concentrates were formulated to contain similar concentrations of crude protein (CP), effective rumen degradable protein (ERDP), metabolizable energy (ME) and digestible undegradable protein (DUP) while three concentrates were formulated in experiment 2 to contain similar concentrations of CP, ME and DUP. The concentrates were prepared using barley, wheat, sugar beet pulp and citrus pulp as energy sources and formulated to achieve a wide range of starch concentrations. Starch concentrations ranged from 50 to 384 g/kg DM and 22 to 273 g/kg DM in experiments 1 and 2 respectively. There were no concentrate energy source by silage type interactions for silage intake, milk yield and composition. It is concluded that increasing starch intake resulted in positive and negative linear relationships for milk protein (P<0.001, R2 = 0.96) and fat (P<0.001, R2 = 0.85) concentrations respectively. Concentrate energy source had no effect on silage DM intake or milk yield.
The end of life on Earth is not the end of the world: converging to an estimate of life span of the biosphere?
Authors: Mello Fernando de Sousa , Friaça Amâncio César Santos
Published: June 2019

Environmental conditions have changed in the past of our planet but were not hostile enough to extinguish life. In the future, an aged Earth and a more luminous Sun may lead to harsh or even uninhabitable conditions for life. In order to estimate the life span of the biosphere we built a minimal model of the co-evolution of the geosphere, atmosphere and biosphere of our planet, taking into account temperature boundaries, CO2partial pressure lower limits for C3 and C4 plants, and the presence of enough surface water. Our results indicate that the end of the biosphere will happen long before the Sun becomes a red giant, as the biosphere faces increasingly more difficult conditions in the future until its collapse due to high temperatures. The lower limit for CO2partial pressure for C3 plants will be reached in 170(+ 320, − 110) Myr, followed by the C4 plants limit in 840(+ 270, − 100) Myr. The mean surface temperature will reach 373 K in 1.63(+ 0.14, − 0.05) Gyr, a point that would mark the extinction of the biosphere. Water loss due to internal geophysical processes will not be dramatic, implying almost no variation in the surface ocean mass and ocean depth for the next 1.5 billion years. Our predictions show qualitative convergence and some quantitative agreement with results found in the literature, but there is considerable scattering in the scale of hundreds of millions of years for all the criteria devised. Even considering these uncertainties, the end of the biosphere will hardly happen sooner than 1.5 Gyr.
Pulsars and their Genesis
Authors: Radhakrishnan V.
Published: June 2019

The subject I have chosen for my talk today will come of age on the last day of this General Assembly. The first detection of the remarkable objects that we call pulsars, was on 28th November 1967 when Jocelyn Bell (now Bell-Burnell) who was working with Prof. Hewish at Cambridge discovered a new class of radio sources that put out pulses of radio radiation about once a second but with clock-like regularity. Two other major discoveries in the same decade using the radio spectrum were, of course, Quasars and the Cosmic microwave background. Those two took us to extremes in time and distance, and the amount of energy radiated, whereas the discovery of pulsars, situated near at hand by comparison, led us to extremes in the physical state of matter.
Requirements for Earth Rotation Parameters
Authors: McCarthy Dennis D.
Published: June 2019

Observations of Earth orientation parameters (polar motion and Universal Time) have reached a level of accuracy which challenges the definition of the reference systems which these observations seek to relate. Observational accuracies of better than in polar motion and in Universal Time are now routinely available. Urgent requirements therefore exist now for the IAU to take a fresh look at the concepts and definitions of the reference systems as well as reference frames. Of particular concern are the definitons of the equinox, the terrestrial reference pole, the zero of longitude and sidereal time.
Reference Frame/Coordinate System in General Relativity
Authors: Fukushima Toshio
Published: June 2019

The order of magnitude of relativistic effects is expressed as the power of v/c where v is a typical speed of objects and c is the speed of light in vacuum. In the neighbourhood of the Earth, v ≅ 30 km/s. Then the magnitudes of the relativistic effects are ordered as follows:
Interpretation of the Data of Epsilon Aurigae
Authors: Kawabata Shusaku
Published: June 2019

Various interpretations of the data of Epsilon Aurigae had been proposed before the recent eclipse. Every model explains the observations to a certain extent, but simultaneously disagrees with some other aspects of the nature of this system. During the 1982-84 eclipse, observations extending from far UV to IR have been carried out. A lot of data have been obtained and discussed in the workshop held at Arizona on this January. The spectroscopy and the photometry in visual region, however, are still important particularly to get informations about dynamical features of the components. In this review we present several interpretations mainly using new data obtained from ground-based spectroscopic observations including ours.
Wind Accretion and Interaction in Long Period Binary Systems
Authors: Kwok Sun
Published: June 2019

Recent observations of the class of objects called symbiotic nova are reviewed. They are suggested to be widely-separated long-period binary systems undergoing mass exchange by wind accretion. Their radio, infrared, optical and X-ray properties are explained by a model of interacting winds.
Interim Discussion of the Orbit of δ Sagittae
Authors: Batten Alan H.
Published: June 2019

New provisional orbital elements are derived for δ Sge and the next conjunction in 1990 should be observed. Probably no bodily eclipse of the B-star will be seen, but an atmosheric eclipse is expected. There are mass motions in the M-star’s atmosphere.
Evidence for the Roche Lobe Overflow in VV Cephei
Authors: Guinan E. F. , McCook G. P. , Koch R. H. , Pfeiffer R. J.
Published: June 2019

The VV Cep close binary system (O8V + M2 lab; P = 20 3 yrs.) is described from published spectral, radial velocity, photometric, and astrometric results. A long-term photometric monitoring program shows intrinsic variability in a red bandpass. Variability exists on several time scales and the longest of these is attributed to tidal distortion of the cool supergiant by the equally massive hot companion. A theoretical “distortion” light curve, when faced against the observations, indicated the radius of the supergiant to be significantly smaller than the accepted value of ~1600R⊙. This conclusion is examined in the context of a pulse of polarized red light occurring near the time of periastron and interpreted as Roche Lobe overflow of the supergiant envelope. It is shown that the photometric and polarimetrie results may be made accordant, not by appeal to a very large level of scattered red light, but rather by invoking the loss of constraint originally imposed by the Roche Lobe geometry.
The PG1159 Variables
Authors: Cox Arthur N.
Published: June 2019

The PG1159 variables, named after the variable of that number in the Palomar-Green blue star catalogue, have high luminoisites, high surface temperatures, and high gravities. Their masses, however, must be the normal low value of 0.6 solar mass because they are the direct antecedents of the classical DB white dwarfs. In every case, they seem to have no hydrogen at all in their atmospheres, but significant helium, carbon, and oxygen is present (Sion, Liebert, and Starrfield 1985). Table 1 gives a list of these stars of which most, but not all, show light variations indicative of nonradial low degree, but probably high order, g modes.
Non-Radial Oscillations in δ Scuti Stars and Rapidly Oscillating AP Stars
Authors: Kurtz D. W.
Published: June 2019

The present state of our knowledge of non-radial oscillations in δ Scuti stars and Rapidly Oscillating Ap stars is discussed primarily from an observational point of view. For the δ Scuti stars the need for complete frequency solutions for multi-periodic non-radial oscillating stars is emphasized in order for stellar seismology of these stars to be possible. An introduction to the Rapidly Oscillating Ap stars is given along with reference to a more complete recent review of those stars.
A New Deep VLA Radio Survey at 6 cm
Authors: Kellermann K. I. , Fomalont E. B. , Weistrop D. , Wall J.
Published: June 2019

We have made a new deep 6 cm survey with the VLA in order to extend the radio source count to a lower flux density and to decrease the limits on the small scale fluctuations in the microwave background. The survey region covers ~10-5 ster and is nearly coincident with the survey previously reported by Fomalont et al. 1984a and 1984b. Both the observing time and bandwidth were increased by a factor of two over the previous survey to give a factor of two improvement in sensitivity.
Coronal Magnetic Fields
Authors: Pallavicini R.
Published: June 2019

It is unfortunate that coronal magnetic fields cannot be easily measured, even in the case of the Sun. Except for a few measurements of magnetic fields in the transition region above sunspots, made using the conventional Zeeman effect, and except for the possibility of inferring the direction – not the intensity – of coronal magnetic fields using optical forbidden lines, direct measurements of coronal fields are virtually non-existent. The most promising method appears to be the use of the Hanle effect, i.e. the modification of polarization characteristics of spectral lines induced by magnetic fields. This method has been proposed for future space missions in solar physics, for instance for the European satellite SOHO, but its feasibility depends on the strength of the fields to be measured, which in any case must be higher than a few tens of Gauss.
Properties of Stellar Magnetic Fields in Close Binaries Deduced from Non-Thermal Radio Observations
Authors: Mutel R. L.
Published: June 2019

Analysis of VLA and VLBI observations of non-thermal radio emission from close binary stellar systems can produce reliable estimates of magnetic field strength and geometry in the source emission region. Assuming a gyrosynchrotron emission model for the non-flare emission, one can model the magnetic field as a relatively small number of stable magnetic loops of overall size R ⋍ (1-3)×1012 cm. with an average field strength of 101 < B < 102 gauss. A correlation of mean fractional circular polarization with inclination angle along with an absence of any clear phase dependence, indicates that the loops are azimuthally symmetric with poles nearly orthogonal to the orbital plane, i.e. axisymmetric dipolar. The loops are probably the same as the loops derived from observations of x-ray emission of ‘hot’ (T ⋍ 107K) coronal gas.
Star Formation, Giant Hii Regions and Spiral Structure
Authors: Rosa Michael
Published: June 2019

The three topics outlined in the title I have been given for this contribution are each far too complex to be thoroughly reviewed in the short time available. Instead of trying to duplicate the relevant (28, 34, 35) Commission Reports in the Transactions of the IAU (R.M. West 1985), I shall review only briefly current results on the stellar content of giant HII regions and then continue towards recent developments of our ideas about the mutual interrelation of galaxy wide star formation and spiral structure. The goal is to emphasize the simultaneous need for descriptions of details and unifying approaches.
Young Stars and Star Formation in Normal Irregular Galaxies
Authors: Hunter Deidre A.
Published: June 2019

A few of the interesting problems concerning star formation in irregular galaxies are reviewed.
Star Formation Bursts in Galaxies
Authors: Lequeux J.
Published: June 2019

We review the tracers of star formation in galaxies and show how they demonstrate the presence of bursts of star formation in various astrophysical contexts: large extragalactic HII regions in spiral and irregular galaxies and in blue compact galaxies, nuclei of some galaxies, extended star formation in other galaxies. We show that strong bursts seem to occur mainly in interacting galaxies. A few comments are made about the theory of such phenomena.
Models of Type II Supernova Explosions
Authors: Hillebrandt Wolfgang
Published: June 2019

Present stellar evolution codes predict that stars with He-core masses above approximately 2 M⊙, corresponding to main sequence masses of at least 8 M⊙ burn carbon non-violently. After hydrostatic core carbon burning all those stars contain O-Ne-Mg cores but their further evolution is strongly dependent on the stellar entropy and thus on the main sequence and the core mass. If the He-core mass is below 3 M⊙ the O-Ne-Mg core grows due to carbon-burning in a shell and the crucial question is, whether or not it grows beyond the critical mass for Neignition (≅1.37 M⊙). Stars with He-cores less massive than about 2.4 M⊙ will never ignite Ne, but due to electron-captures, mainly on Ne and Mg, their cores will contract until O-burning begins. Since the matter of the O-Ne-Mg core is weakly degenerate O-burning propagates as a (subsonic) deflagration front and incinerates a certain fraction of the core into a nuclear statistical equilibrium (NSE) composition of iron-group elements (Nomoto, 1984). If, on the other hand, the mass of the O-Ne-Mg core is slightly larger than 1.37 M⊙ Ne and O burn in a shell from about 0.6 M⊙ to 1.4 M⊙, but again the outcome is a NSE-composition (Wilson et al., 1985). In both cases the core-mass finally exceeds the Chandrasekhar limit because electron captures on free protons and heavy nuclei lower the electron concentration and consequently also the effective Chandrasekhar mass. The cores, therefore, continue to contract and finally collapse to neutron star densities with iron-core masses between 0.7 and 1.4 M⊙.
Effects of Angular Momentum on Supernova Explosion and Stability of Rapidly Rotating Stellar Cores
Authors: Sato Katsuhiko , kiguchi Masayoshi
Published: June 2019

We discuss effects of angular momentum on gravitational collapse and the fate of rapidly rotating stellar cores just before the gravitational collapse. It is found that Stellar cores become dynamically unstable against the modes of P0 and/or P2± 2 before the central densities become higher than the neutron drip density(˜ 4.3×1011 g/cm3). this suggests that fission occurs at pre-supernova stage or in the collapsing stage. In order to make clear whether these dynamical instabilities induce supernova explosion or not, three dimensional hydrodynamic computation would be necessary.
Hipparcos – The Esa Space Astrometry Mission: Overview and Status
Authors: Perryman M.A.C.
Published: June 2019

This paper summarises the key features of the Hipparcos satellite design, and presents an overview of the current project status including results of the evaluation of the first hardware items. A recent assessment of the achievable accuracy for the main mission and for Tycho is also presented.
Correlated Observations of Impulsive UV and Hard X-Ray Bursts from the Solar Maximum Mission
Authors: Cheng Chung-Chieh
Published: June 2019

In the past decade, impulsive hard X-ray bursts have been extensively observed (cf. Kane et al., 1980). These observations have increased our knowledge of the energy spectrum of the accelerated electrons and their temporal evolution. However, because of the lack of spatial resolution and direct plasma diagnostics, many important questions concerning the nature of the impulsive phase are still left unanswered. Since direct imaging of hard X-rays above 30 keV with high resolution of is still beyond our present technology, we have to use other indirect means to deduce the spatial structure of the hard X-ray source. With the recent launch of the Solar Maximum Mission (SMM) satellite, we are able to obtain correlated observations of the flare impulsive phase in hard X-ray and simultaneously in the UV lines of Si IV (1402 Å) and 0 IV (1401 Å). The Si IV/0 IV intensity ratio is density sensitive and therefore provides plasma diagnostics in the emission region. Analysis of the spatially resolved UV observations with the correlated hard X-ray observations allows us to study the spatial structure and physical conditions in the UV and hard X-ray sources (Cheng et al., 1981; 1982; 1984). Descriptions of the various solar instruments on SMM can be found in Solar Physics (vol. 65, pp 5-116). In this paper, I briefly summarize the important observational results and discuss their theoretical interpretation.
Coronal Mass Ejections
Authors: Low B. C.
Published: June 2019

This paper gives a brief review of current observation, interpretation and theory of coronal transient mass ejections. Some recent new results are described.
Coronal Structures Observed at Meter Wavelengths
Authors: Lantos P. , Alissandrakis C.E.
Published: June 2019

Two dimensional maps obtained with the Nançay Radioheliograph at 169 MHz from 1980 are used to describe and identify the features of the quiet sun at meter wavelengths.
Passbands and Photometric Systems
Authors: Rufener F.
Published: June 2019

Synthetic photometry must be used to accurately define the passbands which characterize a photometric system. On the one hand, the colour indices of the stars must be coherent with their absolute spectrophotometry; on the other hand, direct comparisons of model atmospheres with observations must be carried out without resorting to arbitrary transformations. A systematic evaluation procedure could be applied to various photometric systems.
Observed Stellar Energy Distributions for Synthetic Photometry
Authors: Hayes D. S.
Published: June 2019

Observed stellar energy distributions are used in synthetic photometry to evaluate the accuracy of the response functions and to determine the transformation coefficients. The characteristics required of a catalog of energy distributions to be used for synthetic photometry are discussed, and the catalogs found in the literature are reviewed.
Galaxy Formation and Dark Matter
Authors: Rees Martin
Published: June 2019

My aim in this general talk will be to air some questions, rather than offer firm answers, because the most basic questions about galaxies are indeed still unresolved. In particular:

1. We do not know why such things as galaxies should exist at all — why these assemblages of stars and gas with fairly standardised properties are the most conspicuous large-scale features of the cosmos.

2. About 90% of the mass associated with galaxies is hidden. The luminous stars and gas contribute only about a tenth of the gravitating material inferred from dynamical arguments. What the rest consists of is still a mystery.

3. It is unclear why the nuclei of some galaxies flare up, and release the colossal amount of non-stellar radiation emitted from quasars and radio galaxies, as discussed by Maarten Schmidt in his discourse.
The Selection of Scientific and Technical Records for Permanent Retention
Authors: Dudley Janet
Published: June 2019

A small fraction of the enormous volume of records that are generated by research and development activities should be selected for permanent retention because of their potential value to future scientists, engineers, historians and others. The records are generated for many different purposes and in many different forms (not all are documents). There are, however, some basic principles that should be used in appraising the records so that the most appropriate of them are selected according to identifiable criteria.
New Observational Clues on Binary Formation in the Galaxy
Authors: Latham David W.
Published: June 2019

New observations of binaries are beginning to provide new clues on the formation and evolution of binary and multiple systems in a variety of stellar populations in the Galaxy. New orbital determinations are shedding light on the frequency and orbital characteristics of binaries in the disk and the halo of our Galaxy, both in clusters and the field. These results support the view that the formation of binaries involving solar-mass stars is relatively independent of the stellar environment. Evolutionary effects can have a major influence for close binaries with periods up to at least ten days, with a strong dependence on the age of the population. Progress towards determining the frequency of low-mass companions and planetary systems is promising but still very limited.
Binary Frequency Among Pre-Main Sequence Stars in Taurus and Ophiuchus
Authors: Simon M.
Published: June 2019

The lunar occultation technique applied in the IR offers a powerful means of identifying binaries among obscured young stars. Our program has revealed binaries with separations from 1 to 100 AU in the Taurus and Ophiuchus star forming regions to about K=9 mag. To date, 29 objects have been observed; 6 were discovered to be binaries. The observed binary frequency is about half that expected from the binary statistics of a comparable sample of field stars. The discrepancy is probably attributable to our insensitivity to binary systems with secondary mass much less than that of the primary.
Mathematical Status of the Fission Theory
Authors: Lebovitz N. R.
Published: June 2019

A review is given of the current mathematical and theoretical status of the possibility of the formation of binary stars by fission. It is emphasized that none of the competing theories is completely deductive: each begins with a preconception of how fission might occur, and considers mathematical problems that bear on the viability of that preconception. The classical fission theory turned out to lack internal consistency. The present author’s version of the theory, revised from the classical theory in that viscosity plays a negligible rather than a dominant role, appears to be internally consistent and compatible with the idea that close binaries with mass ratios near one may form in this way. The version of the theory described elsewhere in this volume by Durisen, which fails to produce binaries, is based on a preconception of the route to fission different from the classical one. Its failure to produce binaries therefore reflects only on that route, and not on other possible routes to fission.
Numerical Simulations of Fission
Authors: Durisen R. H. , Yang S. , Grabhorn R.
Published: June 2019

Recent hydrodynamic simulations indicate that gravitational torques due to spirals arms suppress binary fission in rapidly rotating polytropic fluids.
Disturbed Binaries: The Early Phases
Authors: de Greve J.P.
Published: June 2019

The disturbance of components and system parameters by mass transfer during and at the end of core hydrogen burning, as well as at the onset of core helium burning is reviewed. Emphasis is given to the influence of the evolution of the gainer and to the variation of the chemical composition of the surface.
Progress of Common Envelope Evolution
Authors: Taam R. E.
Published: June 2019

The current understanding of the common envelope binary phase of evolution is presented. The results obtained from the detailed computations of the hydrodynamical evolution of this phase demonstrate that the deposition of energy by the double core via frictional processes is sufficiently rapid to drive a mass outflow, primarily in the equatorial plane of the binary system. Specifically, recent calculations suggest that large amounts of mass and angular momentum can be lost from the binary system in a such a phase. Since the time scale for mass loss at the final phase of evolution is much shorter than the orbital decay time scale of the companion, the tranformation of binary systems from long orbital periods (> month) to short orbital periods (< day) is likely. The energy efficiency factor for the process is estimated to lie in the range between 0.3 and 0.6.
The AM Her Period Spike
Authors: Lasota J.P.
Published: June 2019

The AM Her period spike is due to the resumption of mass transfer after evolving through the period gap. This implies that (i) at the spike period all secondary stars are the same (ii) most AM Her white dwarfs have a unique mass ⋍0.6 — 0.7M⊙ (iii) nova explosions on magnetic white dwarfs remove exactly the mass accreted between outbursts (iv) the newly discovered AM Her system at 127min has a mass ⋍1.3 — 1.4M⊙ (V) the maximum magnetic field for most AM Her’s is ≤ 4 x 107 G.
Evidence for Asymmetries in SN1987A
Authors: Karovska M. , Koechlin L. , Nisenson P. , Papaliolios C. , Standley C.
Published: June 2019

Results of observations carried out during the past year and a half after the explosion of SN1987A (February 23 1987), show strong evidence for asymmetry in the expanding shell. The departure from spherical symmetry in SN1987A has important implications for further detailed modeling of supernovae explosions, light curves and spectra.
From Interstellar Dust to Comet Dust and Interplanetary Particles
Authors: Greenberg J. Mayo
Published: June 2019

Interstellar dust is described as consisting predominantly (by mass) of tenth micron (mean size) silicate core-organic refractory mantle particles which have evolved over galactic time scales of the order of 5 billion years. These particles were incorporated into comets and asteroids in the presolar nebula 4.5 billion years ago. The fragmentation of those primitive bodies gives rise to solar system debris which shows up as comet dust, zodiacal light, IDP’s and meteorites. The chemical and morphological structure of comet dust is derived here as fluffy aggregates of interstellar dust. The chemical and morphological structure of the chondritic porous IDP’S are then derived from comet dust which has evolved in the solar system. Zodiacal light particles are interpreted as various stages between comet dust and IDP’s. Meteorites appear to be a side branch in the evolution from interstellar to solar system particles.
Microwave Spectroscopy of Astrophysical Molecules
Authors: Irvine William M.
Published: June 2019

Recent detections of new molecules in dense interstellar clouds, first detections of certain chemical elements in interstellar molecules, and new information on isotopic fractionation of hydrogen in the interstellar medium are discussed in the context of the need for new laboratory data on transition rest frequencies, reaction rates, and branching ratios.
Atmospheres of Planets and their Satellites
Authors: Strobel Darrell F.
Published: June 2019

A general review of the chemistry of planetary atmospheres was given with the emphasis on the outer planets and their satellites. The impact of the scientific findings of the Voyager Mission on our understanding of the chemistry and composition of the Jovian, Saturnian, and Uranian atmospheres was highlighted. Hydrocarbon photochemistry will be treated in the context of comparative planetary atmospheres and illustrated by important similarities and differences. The interesting chemistry of satellites with significant atmospheres, Titan, Triton, and Io was explored in the evolutionary context and the impact on the magnetospheres of their parent planet.
The Far-Infrared (IRAS) Excess in Roberts 22 and Related Objects
Authors: Parthasarathy M.
Published: June 2019

From an analysis of the IRAS data of Roberts 22,Ml-92,M2-9,OH 231.8+4.2,M1-91,MWC 922,Hen 401,Mz-3,OH 19.2-1.0 and OH 26.5+0.6 it is found that the characteristics of the dust shells or disks around these objects are similar to that observed in planetary nebulae. These ten objects may be described as transition objects evolving from the tip of AGB towards left in the HR diagram. The bipolar and disk geometry of the dust envelopes around these objects may be the result of large angular momentum of the progenitor star or the central objects may be evolved binary systems embedded in thick disks formed from severe mass loss.
Two-Flow Model for Extragalactic Radio Jets
Authors: Sol H. , Asseo E. , Pelletier G.
Published: June 2019

Different models of extragalactic jet formation have been proposed in the litterature. They usually considered only one population of particles, ascribing one typical bulk velocity to the jet. However from the point of view of plasma physics it seems very likely that beams of particles with different velocity will be generated in the surroundings of the central engine by any kind of jet acceleration mechanism. This can lead to a typical beam-plasma configuration with a slow ambient plasma pervaded by energetic beams which constitute a population inversion and are a potential source of energy and of instability.
The Next Generation: An 8-16 M Space Telescope
Authors: Illingworth Garth D.
Published: June 2019

The Hubble Space Telescope is to be a long-lived observatory with wide-ranging spectroscopic and imaging capability in the UV and the visible, and in the near-IR as the second-generation instruments are implemented. HST will have a dramatic impact on our view of the universe. However, it is by no means premature to address the issue of its successor, even though HST has not yet been launched. We must look ahead with the realistic view that HST will degrade and will need to be replaced. The question that we must then address is:

What is the UV-Visible-IR Observatory that will follow HST?

I will make the case for this being an 8-16 m class telescope.
Infrared Long Baseline Interferometry
Authors: Danchi W.C. , Bester M. , McCullough P.R. , Townes C.H.
Published: June 2019

During the last few years, two new instruments using long baseline interferometry have been constructed for high angular resolution astronomy in the mid-infrared spectral region (8-12 μxm). One called SOIRDETE-Synthese d’Overture en InfraRouge a DEux TElescopes-was built by J. Gay and his collaborators at CERGA. SOIRDETE has a fixed E-W 15 m baseline and two 1 m diameter telescopes of conventional design. This instrument obtains interference fringes by adjusting an optical-precision delay line in discrete steps to compensate for the geometrical delay of the projected baseline. The interference fringe from the source is detected using HgCdTe photodiodes. Because the instrumental delay has discrete steps a time-domain interferogram is created. This interferogram, upon Fourier transformation to the frequency domain, yields information about the spectral characteristics of the source. First fringes have recently been obtained with this instrument (Gay, 1988).
Galactic and Extragalactic Applications
Authors: Field G.B.
Published: June 2019

For the purposes of this talk I will take “high resolution” to mean 1 milliarcsecond (mas). Only objects of high surface brightness when averaged over 1 mas are considered; as H. McAlister will discuss stellar applications, I will speak only about nonstellar applications.
Molecules in Galaxies: Results from Bell Laboratories
Authors: Stark A. A.
Published: June 2019

A decade of galaxy observations at the Crawford Hill 7 m antenna are summarized. Significant results include the mapping of spiral arms in CO, the demonstration that gas in many spiral galaxies is roughly half atomic and half molecular, the detection of extragalactic HCO+, CS, 13CO and C18O, and the observation of molecular material in the halo of M82.
Molecular Clouds in the Large and Small Magellanic Clouds
Authors: Rubio Mónica
Published: June 2019

To determine the distribution of molecular gas in the Large and Small Magellanic Clouds (LMC and SMC), we made complete surveys in the J=1-0 transition of CO, of the central 6°×6° and 3°×2° areas of the LMC and SMC, respectively. The observations were made with the 1.2m Columbia Telescope at Cerro Tololo, which provides and angular resolution of 8.8 arcmin at 115 GHz. The spectral resolution of the surveys was 1.3 km s-1 and the sensitivity in antenna temperature was 0.05 K for the LMC and 0.02 K for the SMC.
Joint Commission Meeting 5, JCM5: Spectroscopy of Individual Stars in Globular Clusters and the Early Chemical Evolution of our Galaxy
Authors: de Strobel G. Cayrel
Published: June 2019

The Proceedings of these two meetings will be edited by G.. Cayrel de Strobel, M. Spite and T. Lloyd-Evans and published by the printing office of Paris Observatory.

We present here an overview of what has been discussed during these meetings.