bluuebunny/crossref_metadata_2025 huggingface dataset:
Fair Sampling of Taxonomic Richness and Unbiased Estimation of Origination and Extinction Rates
Authors: Alroy John
Published: June 2019

Paleobiologists are reaching a consensus that biases in diversity curves, origination rates, and extinction rates need to be removed using statistical estimation methods. Diversity estimates are biased both by methods of counting and by variation in the amount of fossil data. Traditional counts are essentially tallies of age ranges. Because these counts are distorted by interrelated factors such as the Pull of the Recent and the Signor-Lipps effect, counts of taxa actually sampled within intervals should be used instead. Sampling intensity biases can be addressed with randomized subsampling of data records such as individual taxonomic occurrences or entire fossil collections. Fair subsampling would yield taxon counts that track changes in the species pool size, i.e., the diversity of all taxa that could ever be sampled. Most of the literature has overlooked this point, having instead focused on making sample sizes uniform through methods such as rarefaction. These methods flatten the data, undersampling when true diversity is high. A good solution to this problem involves the concept of frequency distribution coverage: a taxon's underlying frequency is said to be “covered” when it is represented by at least one fossil in a data set. A fair subsample, but not a uniform one, can be created by drawing collections until estimated coverage reaches a fixed target (i.e., until a “shareholder quorum” is attained). Origination and extinction rates present other challenges. For many years they were thought of in terms of simple counts or ratios, but they are now treated as exponential decay coefficients of the kind featuring in simple birth-death models. Unfortunately, these instantaneous rates also suffer from counting method biases (e.g., the Pull of the Recent). Such biases can be removed by only examining taxa sampled twice consecutively, three times consecutively, or in the first and third of three intervals but not the second (i.e., two timers, three timers, and part timers). Two similar equations involving these counts can be used. Alternative methods of estimating diversity and turnover through extrapolation share some of the advantages of quorum subsampling and two-timer family equations, but it remains to be shown whether they produce precise and accurate estimates when applied to fossil data.
Using a Macroecological Approach to Study Geographic Range, Abundance and Body Size in the Fossil Record
Authors: Lyons S. Kathleen , Smith Felisa A.
Published: June 2019

Macroecology is a rapidly growing sub-discipline within ecology that is concerned with characterizing statistical patterns of species' abundance, distribution and diversity at spatial and temporal scales typically ignored by traditional ecology. Both macroecology and paleoecology are concerned with answering similar questions (e.g., understanding the factors that influence geographic ranges, or the way that species assemble into communities). As such, macroecological methods easily lend themselves to many paleoecological questions. Moreover, it is possible to estimate the variables of interest to macroecologists (e.g., body size, geographic range size, abundance, diversity) using fossil data. Here we describe the measurement and estimation of the variables used in macroecological studies and potential biases introduced by using fossil data. Next we describe the methods used to analyze macroecological patterns and briefly discuss the current understanding of these patterns. This chapter is by no means an exhaustive review of macroecology and its methods. Instead, it is an introduction to macroecology that we hope will spur innovation in the application of macroecology to the study of the fossil record.
Using Confidence Intervals to Quantify the Uncertainty in the End-Points of Stratigraphic Ranges
Authors: Marshall Charles R.
Published: June 2019

One of the many contributions paleontology makes to our understanding of the biosphere and its evolution is a direct temporal record of biotic events. However, assuming fossils have been correctly identified and accurately dated, stratigraphic ranges underestimate true temporal ranges: observed first occurrences are too young, and observed last occurrences are too old. Here I introduce the techniques developed for placing confidence intervals on the end-points of stratigraphic ranges. I begin with the analysis of single taxa in local sections – with the simplest of assumptions – random fossilization. This is followed by a discussion of the methods developed to handle the fact that the recovery of fossils is often non-random in space and time. After discussion of how confidence intervals can be used to test for simultaneous origination and extinctions, I conclude with an example application of confidence intervals to unravel the relative importance of background extinction, environmental change and mass extinction of ammonite species at the end of the Cretaceous in western Tethys.
Ostracodes and Their Shell Chemistry: Implications for Paleohydrologic and Paleoclimatologic Applications
Authors: Ito Emi , De Deckker Patrick , Eggins Stephen M.
Published: June 2019

The shell chemistry of ostracodes is a useful indicator of past environmental conditions especially when the chemistry data are considered along with other proxy data. The complexities involved with the chemical and isotopic changes accompanying hydrologic change, solute evolution, and the autoecology of ostracodes all point to the need to exercise caution when interpreting shell chemistry. Nevertheless, the stable-isotope values and cation ratios (e.g., Mg/Ca, Sr/Ca) as well as the species assemblage of ostracodes can provide powerful tools for the reconstruction of paleoclimate and paleohydrology. In particular, the changes in Mg/Ca and Sr/Ca of well-calcified ostracodes shells record the qualitative changes in solute composition, and when the dissolved Mg/Ca remains relatively constant, the Mg/Ca in the ostracode shell is proportional to water temperature.
Ostracoda on the Internet
Authors: Kaesler Roger L. , Cormack Michael S.
Published: June 2019

Information abounds on the Internet. Information about the Ostracoda is no exception. Here we assess 40 web sites that deal fully or in part with a wide variety of aspects of ostracode biology, paleontology, and ecology.
Agricultural drought impacts on crops sector and adaptation options in Mali: a macroeconomic computable general equilibrium analysis
Authors: Montaud Jean-Marc
Published: June 2019

In Mali's current context, where the crops sector is particularly exposed and vulnerable to agricultural drought, this study assesses the economy-wide impacts of such events and the potential effectiveness of some adaptation strategies. Using a dynamic computable general equilibrium model, we conduct counterfactual simulations of various scenarios accounting for different levels of intensity and frequency of droughts over a 15-year period. We first show how mild, moderate and intense droughts currently experienced by the country affect its economic performance and considerably degrade the welfare of its households. We also show how these negative impacts could be aggravated in the future by the likely increased number of intense droughts threatened by global climate change. However, we finally show that there appears to be some room for Mali to maneuver in terms of drought-risk management policies, such as fostering the use of drought-tolerant crop varieties, improving drought early warning systems or extending irrigation capacities.
Faith and the Existence of God
Authors: Swinburne R. G. , Barrett D. C.
Published: June 2019

Arguments move from premises to conclusions. The premises state things taken temporally for granted; if the argument works, the premises provide grounds for affirming the conclusion. A valid deductive argument is one in which the premises necessitate, that is, entail, the conclusion. (It would involve a self-contradiction to assert the premises but deny the conclusion.) What I shall call a ‘correct’ inductive argument is one in which the premises in some degree probabilify the conclusion, but do not necessitate it. More precisely, in what I shall call a correct P-inductive argument the premises make the conclusion probable (i.e. more probable than not); in what I shall call a correct C-inductive argument, the premises add to the probability of the conclusion (i.e. confirm it, make it more probable than it was; but do not necessarily make it overall probable). Arguments only show their conclusions to be true if they start from true premises; arguments of the above types which work (i.e. are valid or correct) and do start from such premises I will call sound arguments. Arguments are only of use to show to an individual that the conclusion is true if he already knows the premises to be true. Most of what I shall have to say today concerns arguments with respect to which there is no doubt that the premises are true.
Is Drift a Serious Alternative to Natural Selection as an Explanation of Complex Adaptive Traits?
Authors: Sober Elliott
Published: June 2019

‘There are known knowns; there are things we know we know. We also know there are known unknowns; that is to say we know there are some things we do not know. But there are also unknown unknowns—the ones we don't know we don't know.’
Needs, Facts, Goodness, and Truth
Authors: Lowe Jonathan
Published: June 2019

In this paper I want to explore certain parallels between the logic of action and the logic of belief or, as it might otherwise be put, between practical and theoretical reasoning and rationality. The parallels will be seen to involve an ontological dimension as well as psychological and linguistic dimensions. It may help to begin by mentioning how I was drawn into an examination of these parallels. This was through becoming convinced of the correctness of an externalist account of reasons for action, having been persuaded of this by, amongst other things, arguments found in Jonathan Dancy's recent book on the subject, Practical Reality. Externalism about reasons for action appeared to me to be, on reflection, the only view that one could plausibly adopt in conjunction with a libertarian account of free will—the latter being a position which I am now convinced is not only coherent but entirely defensible and indeed correct. Oddly enough, however, recent debates concerning internalist versus externalist accounts of reasons for action tend to have been dominated by moral philosophers, whereas those concerning compatibilist versus libertarian accounts of free will tend to have been dominated by philosophers of action. As a consequence of this, the two debates have been carried on relatively independently of each other—in my view, to the detriment of both. The present paper is part of a larger exercise of trying to bring them together.
Needs, Rights, and Collective Obligations
Authors: Wringe Bill
Published: June 2019

Normative political discussion can be conducted in a variety of different vocabularies. One such is the vocabulary of rights; another is that of needs. Others, with which I shall be less immediately concerned, are the vocabularies of common good and perhaps-although one might regard it as such a general term as to be common to almost all the terms in which one might conduct normative discourse-that of moral obligation.
Needs and Capabilities
Authors: Alkire Sabina
Published: June 2019

How should actions to redress absolute human deprivation be framed?1 Current international coordinated actions on absolute poverty are framed by human rights or by goals such as the Millennium Development Goals. But appropriate, effective and sustained responses to needs require localized participation in the definition of those rights/goals/needs and in measures taken to redress them. Human rights or the MDGs do not seem necessarily to require such processes. For this reason some argue that no universal framework can describe economic, social, or cultural rights. Yet to address absolute poverty purely from the local perspective still requires the identification and prioritization of capabilities or needs, and often requires actions by greater-thanlocal institutions, so in practical terms a framework is not rejected without cost. This paper argues that the identification and prioritisation of rights or MDGs can and should be done at an international level, but that they might be framed as capabilities, and that far greater attention need be given to the iterative specification of these rights, and to the ongoing protection of certain agency freedoms. The paper explores how Wiggins' account of need can fruitfully inform the specification of needs claims. It also draws significantly on Sen's work to identify the intrinsic importance of process and opportunity freedoms, and to identify how these can relate to universal priorities.
Against Egalitarianism
Authors: Kekes John
Published: June 2019

It is possible that the fame of the Texas Rose Rustlers Society has not yet reached readers of these words. They may want to know then that its members prize roses that survive unattended in the wilds of Texas, having eluded the benevolent attention of gardeners. These unattended roses are not too distantly related to the ‘unofficial English rose’ that the poet says ‘Unkempt about those hedges blows’ in the proximity of The Old Vicarage at Grantchester. As all respectable societies, the Texas Rose Rustlers has by-laws stating the principles that unite its members. Here are some of them: there is more than one way of being beautiful; good climates are in the eye of the beholder; if you are attacked by disease, abandonment, or a bad chain of events, do not despair, there is always the chance that you were bred to be tough; and everyone should not smell the same. I mention these admirable principles because they offend profoundly against egalitarianism, which happens to be my target on this occasion.
The Epistemology of Unjust War
Authors: Putnam Hilary
Published: June 2019

My friend Steven Wagner, a philosopher I very much admire, recently wrote me that he finds ‘Just War Theory’ in its present form wholly untenable. With his permission, I shall quote part of what he wrote:

Here's what I meant about just war theory (JWT) and ontology. The formulations of JWT effectively identify three distinct objects: a population, a nation, and the high-level decisionmakers in the government. Therefore, even if JWT is invoked in the cause of peace, it surrenders the larger battle by buying into an authoritarian political ontology. So it's an irremediably spoiled tool for justice.
Do young adults value sustainable diet practices? Continuity in values from adolescence to adulthood and linkages to dietary behaviour
Authors: Larson Nicole , Laska Melissa N , Neumark-Sztainer Dianne
Published: June 2019

Objective:

To describe continuity over time in reports of valuing sustainable diet practices and investigate relationships between values, household meal behaviours and dietary intake.

Design:

Observational study. Participant ratings of how important it is for food to be produced as organic, not processed, locally grown and not GM were categorized to represent whether they valued (very/somewhat important) or did not value (a little/not at all important) each practice. Diet quality markers (e.g. fruit servings) were based on an FFQ.

Setting:

Mailed and online surveys.

Participants:

Young adults (n1620; 58 % female, mean age 31 (sd1·6) years) who were participating in Project EAT (Eating and Activity among Teens and Young Adults) and responded to follow-up surveys in 2003–2004 and 2015–2016.

Results:

One-third (36·1 %) of participants reported valuing <2 practices at both assessments; 11·1 and 34·5 % respectively reported valuing ≥2 practices in 2003–2004 only and in 2015–2016 only; 18·3 % reported valuing ≥2 practices at both assessments. Regression models including demographics, parental status and vegetarian status showed that valuing ≥2 practices was associated with preparation of meals with vegetables at least a few times/week, less frequent purchase of family meals from fast-food restaurants, and higher diet quality in 2015–2016. For example, those who valued ≥2 practices consumed nearly one full vegetable serving more than other young adults on an average day and part of this difference was specifically associated with intake of dark green and red/orange vegetables.

Conclusions:

Addressing the sustainability of food choices as part of public health messaging may be relevant for many young adults.
Morphological Characteristics of the Developing Cecum of Japanese Quail (Coturnix coturnix japonica)
Authors: AbuAli Aalaa M. , Mokhtar Doaa M. , Ali Reda A. , Wassif Ekbal T. , Abdalla K. E. H.
Published: June 2019

The current investigation was carried out to record the final stages of the development of both middle and distal parts of quail ceca,Coturnix coturnix japonicato understand the role of ceca in digestion, immune system, and absorption. The cellular and subcellular structures, including epithelial cell height, microvillus surface area, the proportion of goblet cells, the thickness of muscle layer, and cecum diameter showed great variations during the development. An undeveloped smooth muscularis mucosa was observed for the first time on the ED5. Primordia of glands were observed on the ED7. On the ED15, the middle part exhibited two shapes of mucosal villi: tongue-shaped villi and U-shaped. The plicae and crypts of Lieberkühn were demonstrated on the hatching day. The lymphatic tissues appeared in the wall of both parts of the ceca at the 4 weeks of age. Scanning electron microscopy revealed a great difference in the mucosal surface between different regions. Telocytes were observed in-between the muscle fibers and formed a network during the post-hatching period. Because of fermentation and other bacterial or chemical processes that have been shown to occur in the ceca, this study supports two hypotheses: the cecal development is related to diet and the cecal epithelium act as a site for primary absorption of nutrients or for re-absorption of electrolytes or amino acids derived from the urine.
Reduced heat tolerance in fast-growing broilers
Authors: Cahaner A. , Deeb N.
Published: June 2019

Broiler breeders conduct their breeding programs only in optimal environments, claiming that because farmers are instructed to provide the broilers with optimal management, genotype by environment interactions (GxE) are not important for the broiler industry. However, with the rapid development of the poultry industry worldwide, high-performance broiler stocks are now being imported to developing countries where environmental control, mainly the mitigation of hot climates, is not feasible. Moreover, results from several studies suggest that due to the increase in genetic potential for rapid growth rate, resulting from successful breeding programs, broilers are becoming more sensitive to rather small environmental deviations from optimal conditions (Leenstra and Cahaner, 1991; Cahaner and Leenstra, 1992; Cahaner et al., 1993; Settar et al., 1999; Yunis et al, 1999). Hence, also in developed countries, many broilers will be, or are already being reared under suboptimal hot environments.
Disease and biosecurity constraints to trade in animal products
Authors: James A.D.
Published: June 2019

The major centres of consumption of animal products are countries of relatively high per capita income and human population density. In these countries, the cost of production of animal product tends to be high. In particular, land and labour prices are higher than in less populous and wealthy countries. This also tends to encourage the adoption of more intensive animal production systems, often associated with adverse effects on animal disease risk, product quality, animal welfare and the environment.
Validation of the n–alkane technique to measure intake and digestibility in Alentejano pigs under “Montanheira”
Authors: Ferraz de Oliveira M. I. , Trigo A. P. , Neves J. A. , Cancela d´Abreu M.
Published: June 2019

In the traditional silvo–pastoral system, Alentejano pigs are fattened with acorns and pasture. Although this production system (“Montanheira”) has been characterised, there is a lack of knowledge on intake and digestibility of the diet, mainly due to the absence of tested methodologies in pigs. The n–alkane technique, extensively used in ruminants to estimate diet intake and digestibilitiy, has had less use in pigs. The objective of this experiment was to validate the n–alkane technique in Alentejano pigs. Faecal recoveries of natural and dosed n-alkanes, the diurnal variation of faecal n–alkane concentration, and the time span required to reach a steady state excretion of dosed alkanes were determined. Eight male Alentejano pigs (54.4±9.8 kg LW) were randomly allocated to two groups and placed in metabolic cages. They were fed 0.7 kg of pasture and 0.7kg of ground acorns daily as two meals. Pigs in Group-1 were given once daily artificial C32(40mg/d) and C36(40 mg/d) and those in Group-2 the same alkanes as two daily doses of 20 mg. Steady state excretion of both alkanes was reached 3 days after first dosing. Although no difference (P>0.05) was observed between treatments, the coefficient of variation of feacal alkane concentration when dosed twice daily was generally lower than when dosed once daily. Mean faecal recoveries of n–alkanes increased with increasing carbon-chain length (C25to C36) from 38 to 69%, but were not significantly different from C29, C32, C33and C36(mean 0.694 SEM 0.067). Faecal nalkanes in samples collected every four hours for three days showed no diurnal variation in patterns of excretion apart from a higher concentration of C324 hours after dosing once daily. However variation between animals was lower when artificial alkanes were dosed twice daily than when once daily. The results indicate that the n–alkane techique may be used to estimate intake and digestibility under “Montanheira”, although further validation work needs to be done.
Mean chewing time in horses fed different forages supplemented with concentrates
Authors: Noergard P. , Raff L. , Poulsgaard U. , Eriksen L. , Soeland T.M.
Published: June 2019

A 3 x 3 Latin square design was conducted with 3 trotters (mean weight 510 kg) fed concentrates supplemented with 5.0 kg wrap bale grass silage (WS), 7.0 kg mixed hay (H) or 6.0 kg barley straw (BS) daily. Amounts of concentrates were adjusted to cover maintenance energy requirements together with forage. Concentrates, WS, H and BS had 86, 80, 86, and 87% DM with 350, 560, 610 and 740 g NDF/kg DM, and 190, 350, 390 and 490 g ADF/kg DM, respectively. Forages and concentrates were fed twice daily, but during the 4 experimental days, the horses had access to one quarter of the daily forage ration for 60 minutes at 9 am, 11 am, 1 pm and 3 pm. Forages not eaten within each of the four meals were recorded and fed again at 4 pm. Eating behaviour was observed and jaw moments (JM) recorded from 7 am to 4 pm by measuring pressure oscillations (PO) in a tube filled with water positioned around the mouth. Effective time spent chewing (ECT) and the numbers of jaw movements (JM) were identified from the manual observations and JM with exclusion of small pauses without mastication. The number of JM, the effective chewing rate and the ECT values per kg forage DM, forage NDF and forage ADF differed significantly (P<0.01) between forages and between forages and concentrates (P<0.01). The mean ECT values ranged from 50±4.7 minutes per kg WS dry matter to 100±4.7 minutes per kg BS dry matter, and from 90± 6 minutes per kg WS NDF to 135±6 minutes per kg BS NDF. The highest chewing rate (1.45±0.06 Hz) was found during concentrate meals and the lowest during BS meals (1.20±0.05 Hz). The horses spent more time eating (min/kg NDF) forages compared with values reported from cattle eating forages, whereas the total ECT values of 90 to 135 minutes chewing time per kg NDF in horses range from 60 to 90% of the time dairy cows to spent masticating during eating plus ruminating.
Food intake regulation in late pregnancy and early lactation
Authors: Ingvartsen K. L. , Friggens N. C. , Faverdin P.
Published: June 2019

The dip in food intake, which starts in late pregnancy and continues into early lactation, has traditionally been interpreted as a depression in intake due to physical constraints. However, the rôle of physical constraints on intake has been overemphasized, particularly in early lactation. There is mounting evidence that the presence and mobilization of body reserves in early lactation play an important rôle in regulating intake at this time.

Conceptually, the dip in intake in early lactation observed when cows have access to non-limiting foods can be accounted for by assuming that the cow has a desired level of body reserves. When the cow is not compromised, the changes with time in body reserves and the dip in intake represent the normal case and provide the basis against which to assess true depressions in intake which may occur when the cow is compromised by limiting nutrition or environment.

The regulation of body reserves and intake in the periparturient cow is orchestrated through nervous and hormonal signals. Likely factors that are involved in intake regulation are reproductive hormones, neuropeptides, adrenergic signals, insulin and insulin resistance and leptin. Furthermore, oxidation of NEFA in the liver may result in feedback signals that reduce intake. The relative importance of these is discussed. A better understanding of the physiological signals involved in intake regulation and their interrelations with body weight regulation may provide important indicators of the degree of compromise that periparturient cows may experience.
Uses and Required Characteristics of Reference Frames for Galactic Astronomy
Authors: Wielen Roland
Published: June 2019

Galactic astronomy requires mainly accurate proper motions of stars, referred to a system which represents an inertial system as closely as possible. We discuss the required accuracy, give an outlook on forthcoming reference frames of use for galactic astronomy, and discuss observationally determined upper limits on the rotation of the extra-galactic reference frame.
On the Use of Natural References
Authors: Capitaine N. , Guinot B. , Souchay J.
Published: June 2019

The catalogues of positions of radio-sources obtained by VLBI, their link with precise and dense star catalogues (HIPPARCOS) and the atomic time open an era where “natural” references in space and time will be quasi-ideal. Are our traditional concepts and usages adapted to this new situation?
Solar and Solar-Like Oscillations: Theory
Authors: Gough D.O.
Published: June 2019

Solar five-minute oscillations provide a means of testing theoretical models of the sun. By judiciously combining data from low-degree modes, properties of the central and surface regions of the sun can be inferred separately. In principle, it should be possible to draw similar inferences from other stars, once adequate data are available. Recent solar rotational splitting data imply that in the equatorial regions much of the radiative envelope of the sun is rotating more slowly than the photosphere.
Chemical Evolution of Galaxies
Authors: Pagel B E J
Published: June 2019

This paper discusses the initial mass function, the oxygen yield and the helium abundance in irregular and blue compact galaxies.
Centenary of S Andromedae (SN 1885a)
Authors: van den Bergh Sidney
Published: June 2019

Observations by Hartwig, Wolf, Dunér and Bigourdan are used to show that SN 1885a reached MV(max) = −18.8 ± 0.5 on 17 or 18 August 1885. The lightcurve of S And is found to have declined more rapidly after maximum than that of any other well-observed supernova. The existence of S And and the relatively young age of the supernova remnant Sgr A East appear to indicate that the supernova frequencies near the nucleus of M31 and the Galactic centre are respectively ∽102and ∽103times higher than expected. It is spectulated that S And may belong to a population of supernovae (“type 0”) that only occur near the nuclei of giant galaxies. Beyond the Local Group such objects might perhaps have been missed because of their fast decline and close proximity to luminous nuclei.
Coronal Activity at Radio Wavelengths
Authors: Kundu M.R.
Published: June 2019

We describe the multifrequency radioheliograph of the Clark Lake Radio Observatory. Its use for studies of large scale structures of the corona at long radio wavelengths is discussed. We show that features corresponding to coronal streamers and coronal holes are readily apparent in the Clark Lake maps. We also present results on studies of microbursts at meter-Decameter wavelengths.
Cloud Collapse and Fragmentation
Authors: Boss A. P.
Published: June 2019

Interstellar clouds are thought to undergo a rapid phase of collapse in the process of contracting to form stars. Break-up during this collapse phase is termed fragmentation. Computer codes capable of calculating the hydrodynamics of cloud collapse in three spatial dimensions have been used to study the fragmentation process. Fragmentation into binary or multiple protostellar systems is the preferred outcome of collapse; only very slowly rotating, high thermal energy clouds, or clouds starting from power-law initial density profiles, avoid fragmentation and form single stars.
Three Dimensional Hydrodynamical Simulation of Type II Supernova
Authors: Nagasawa Mikio
Published: June 2019

Adiabatic supernova explosions of polytropic stars are investigated by a three dimensional Smoothed Particle Hydrodynamics. The evolution of thermal point explosions is almost spherically symmetric in a global sense, but they are found to be unstable against Rayleigh-Taylor instabilities. The typical unstable wavelength, which grows in the nonlinear stage, is comparable to the thickness of the spherical shell. As a result, we find a porous density structure on the expanding shell. These results suggest the dumpiness of the ejecta of supernova explosions. The accompanying mixing motion in the expanding shell can explain the rapidly rising light curve of SN1987A. Because it may mix up the energy source 56Ni towards the outer layers of supernovae.
Non-Equilibrium Thermal X-Ray Emission in the Early Phase of Supernova Remnant
Authors: Hanami Hitoshi , Yoshida Tatsuo
Published: June 2019

The X-ray emission from the interaction of the ejecta with circumstellar matter (CSM) for SN1987A is investigated. The electron and the ion temperatures seem to be in non-equilibrium in the early phase of a SN remnant. We have studied the two-temperature model in the early phase of SNR and discuss the X-ray emission from SN1987A and its CSM.
Dust from the Comets
Authors: Mukai Tadashi
Published: June 2019

We have found a similarity between the size spectra of the observed interplanetary dust and the survived cometary dust, referring to the dynamical behaviour of the dust leaving the comet. As a result, we can suggest that short-period comets with relatively higher eccentricities are major source of the interplanetary dust, especially those with radii less than 10 µm. It is predicted, furthermore, that a supply rate of the dust, which move on bound orbits after leaving the comet, becomes about 8×10 g/s from 85 short-period comets, and nearly 3×104g/s from 101 long-period comets.
Hubble Space Telescope Second Generation Instrument Selection
Authors: Weiler E. J.
Published: June 2019

The Hubble Space Telescope Second Generation Instrument Program is described. The original instrument selection process in 1985 is discussed as well as the NASA plan to make a final selection of an infrared instrument in late 1988.
CORONAL INSTABILITIES
Authors: Einaudi G.
Published: June 2019

The interest in the stability of coronal structures derives from their observed lifetime (much longer than the relevant hydromagnetic timescale) coupled with their active behavior. This fact implies that these structures must be globally stable with respect to fast and destructive instabilities and, at the same time, must allow some local, non-disrupting, dissipative process to take place. In highly magnetized media as solar and stellar coronae a large number of plasma instabilities can occur. The present review will concentrate on those governed by the magnetohydrodynamic (MHD) equations with the inclusion of the effects of finite resistivity and viscosity and the use of an energy equation where radiation, mechanical heating and thermal conduction are considered.
Millimeter Wave Interferometry
Authors: Downes D.
Published: June 2019

Millimeter interferometers give high-resolution (few arc sec) information on cool (100-1000 K) matter, which cannot be easily studied by other techniques. The objects include regions of high extinction (Ay ~ 10–200 mag), planetary atmospheres, outflows from forming stars, mass loss from stellar envelopes and molecular clouds in galaxies. The advantages which mm arrays have over cm arrays are the greater number of molecular spectral lines and the larger linewidths, which allow a higher sensitivity for the same angular resolution and system performance. In the continuum mm arrays can observe solar system objects, stellar winds, compact HII regions, galaxies and quasars in thermal and synchrotron emission, and thermal radiation from dust in dense clouds. The main technical challenges are (1) sensitivity, which limits the longest usable antenna spacing, (2) small field of view, and (3) atmospheric effects, which introduce phase noise. For the next 5–10 years, the main arrays will be those of the Berkeley-Illinois-Maryland collaboration, Cal Tech, Nobeyama and IRAM. There are proposals to add more antennas to existing arrays, to build new ones, and to extend their cover to higher frequencies.
Ground-Based Photometric Calibration of the Space Telescope CCD Camera
Authors: Hunter D.A. , Harris H.C. , Baum W.A. , Jones J.H. , Kreidl T.J.
Published: June 2019

The Wide-Field and Planetary Camera (WF/PC) is a CCD imaging instrument which is part of the Hubble Space Telescope. Ground-based observations have been made with a CCD system similar to those of the WF/PC in order to establish the standard star sequence to be used for in-flight photometric calibration. Because the WF/PC passbands differ from those in previous photometric use, the filters and CCDs will define a new photometric system. We outline here the procedures used to establish the calibration fields to be used in flight (see Harris et al. 1988 for additional details).
Stars in the Rosat All-Sky Survey
Authors: Schmitt J.H.M.M.
Published: June 2019

The ROSAT all-sky survey has now been completed and the analysis of this huge body of data is in progress. While final results on the number of detected X-ray sources and their distribution in flux are not yet available, the total number of X-ray sources is expected to be around 60 000. Preliminary results from optical identifications of selected fields show that about one quarter of the X-ray sources discovered at high galactic latitudes come from by comparison nearby stellar sources (Fleming 1991), while at lower galactic latitudes up to one half of the detected X-ray sources are of stellar origin; in areas occupied by star forming regions (for example, Orion) or open clusters (for example, Hyades or Pleiades) a large number of the detected X-ray sources can be identified with young stars, yielding up to 80 percent of the total source count as galactic stars. For the whole of the ROSAT all-sky survey we may therefore expect about one third of the total sources to be of stellar origin. The vast majority of these stellar X-ray sources is of coronal origin (i.e., late-type low mass stars). Only a relatively small number of stellar X-ray sources will be associated with early-type massive stars where the X-ray emission is thought to arise from instabilities in their radiatively driven winds or metal-poor degenerate stars where the X-ray emission comes from portions of the atmosphere considerably hotter than the optically visible photosphere. From the preliminary analyses performed so far it is already clear now that supersoft sources such as white dwarfs do not constitute a major fraction of the X-ray source population found in the ROSAT all-sky survey and the number of newly X-ray discovered white dwarfs will certainly be considerably less than one thousand. The X-ray emitting late-type stars are commonly referred to as “active” stars, and the ROSAT all-sky survey catalog will comprise the most extensive list of such objects.
Deep 10 and 15 GHZ Searches for CMB Anisotropies
Authors: Davies R. D. , Lasenby A. N.
Published: June 2019

The search for anisotropies in the Cosmic Microwave Background (CMB) is fundamental to observational cosmology: it requires observations on a range of angular scales and at a range of frequencies to distinguish CMB structure from foreground galactic structure. We have made significant progress in setting new limits to CMB anisotropies on angular scales of 3°-12° using scaled observing systems at 10 and 15 GHz. This regime of angular scales is particularly matched to the predictions of Cold Dark Matter (CDM) and isocurvature scenarios of galaxy formation in the early Universe.
Upper Limits on Sub-Arcminute Fluctuations in the CBR
Authors: Partridge R. B.
Published: June 2019

The use of aperture synthesis allows one to search for fluctuations in the CBR on angular scales below 1 arcminute. I report here tentative results of an experiment carried out with E. B. Fomalont, R. Windhorst and J. Lowenthal using the Very Large Array of the National Radio Astronomy Observatory in New Mexico. We used the instrument in its tightest configuration and at a wavelength of 3.6 cm; the corresponding angular resolution was ~10”. We were able to set limits on fluctuations in the CBR on a range of angular scales, 10”-90”, and these are among the most sensitive upper limits on CBR fluctuations yet published.
Comets and Constraints on Solar System Formation
Authors: Levasseur-Regourd A.Chantal
Published: June 2019

New and important data have been obtained during the 1985-1986 return of comet Halley, including in situ observations of the nucleus and the coma. Since the interpretation of the observations is not straightforward, the results are presented in a rather conservative manner. Some clues to the solar system formation are suggested, e.g. the shape of the nucleus, its low density, the estimated mass of the Oort cloud, the elemental abundances in comet Halley. Constraints related to isotopie abundances (deuterium enrichment, possible anomalies in carbon isotopes) and to cometary dust (complex organic compounds, submicron sized dust particles) are extensively discussed.
Link to an Inertial System
Authors: Argue A.N. , White Graeme L.
Published: June 2019

The homogeneous positional reference frame to be established by Hipparcos must be brought into coincidence with the new IAU frame based on extragalactic radio sources. A review is given of the methods by which this is to be achieved.
GHRS Observations of Massive Stars in the Large Magellanic Cloud
Authors: Shore Steven N.
Published: June 2019

Hot stars are the natural targets for ultraviolet space observations. The bulk of their energy emerges shortward of the atmospheric cutoff and nearly all of the important atomic transitions required for their analysis are located in the region shortward of λ3000Å. However, since they are intrinsically rare, reddening and distance conspire to make the job of studying these important members of the stellar population of a galaxy a very difficulty task. The Goddard High Resolution Spectrograph (GHRS) adds the new dimension of photon counting to high sensitivity and resolution. This means that the massive stars can be more easily observed within our Galaxy, and also in other galaxies.
Circumstellar Lines in Beta Pictoris
Authors: Boggess Albert
Published: June 2019

Beta Pictoris has attracted special attention since the detection of circumstellar (CS) dust emission by the Infrared Astronomy Satellite (Aumann et al 1984) and subsequent imaging of an extended disk (Smith & Terrile 1984). A central cavity in the dust disk (Telesco et al. 1988) and episodes of infalling high-density gas (Kondo & Bruhweiler 1985) have also been found. The infalling gas is highly variable in infall velocity and mass rate (Bruhweiler, Kondo & Grady 1991). Sporadic mass outflow events have also occurred, implying that some of the CS gas may be stellar ejecta.

These observations of the gas around β Pic by the Goddard High-Resolution Spectrograph (GHRS) represent a significant enhancement in velocity resolution and S/N over previous UV studies of this star and permit for the first time a simultaneous probe of the density and velocity structure of the CSgas.
Introductory Remarks on Late Stages of Evolution of Low-Mass Stars
Authors: Habing H.J.
Published: June 2019

These largely historical remarks were meant for those in the audience that had not followed the developments in recent years.

One of the great achievements of astrophysics in this century was the discovery of the source of the solar (and stellar) energy: the fusion of hydrogen into helium. It became also clear that once the conditions for hydrogen burning become unfavourable the star switches to the burning of helium: a contraction of the central region increases the temperature and pressure until the helium starts to burn into carbon and oxygen. In this way one imagines that stars during their lifetime go through successive phases of atomic fusion, with the endproduct of the previous phase as the fusion element for the one following. This succession can continue until the iron core is reached; thereafter the fusion becomes exothermic, and is no longer a viable source of energy; perhaps a supernova should follow here. As we know now (and will be discussed here), this succession is interrupted by mass loss; most stars do not develop beyond the second core, one of carbon and oxygen.
The IR Color Evolution of Circumstellar Shells
Authors: Lewis B. M. , Terzian Yervant
Published: June 2019

The far IR colors of circumstellar shells are delimited by those with masers; few other objects share the same colors. The resulting (25–12)µm color range is primarily due to secular increases in the mass-loss rate, up to a progenitor-mass dependent maximum. Only the most massive progenitors can sustain the mass-loss rate required by the reddest shells.
Archival of Radio Source Catalogues: Present Status and Prospects
Authors: Andernach Heinz
Published: June 2019

Recent proliferation of large radioastronomical source surveys and resulting data products are reviewed, and attention is drawn to their poor archival status. First practical steps are proposed to establish a radio source data base from published source catalogues, proceeding with time from the bigger and recent ones to the smaller and older ones. At later stages the data base could assimilate unpublished data, spectral-line data and also images.
The HST Observations Archive at ST ScI
Authors: Allen Ron
Published: June 2019

1.

All data generated by HST are preserved in a specially-designed interim archive system, the “Data Management Facility” at ST ScI.

2.

Data is currently being written to 2 Gb – 12” optical disks at the rate of about 0.5 Gb/day = 35 exposures/day.

3.

A catalog is produced as the data is archived. This catalog is publically accessible and currently contains information on over 19,000 exposures (images, spectra, flat fields, calibration data, etc.)

4.

About 14,000 exposures are now non-proprietary; more than a third of these are observations of sky targets obtained during OV/SV.
Archiving
Authors: Jaschek Carlos
Published: June 2019

Astronomy is a natural science based upon observations. Observations are made by somebody at a given time and place, obtained with certain instruments using certain techniques and are interpreted with the help of certain models or theories. The latter may change with time, but observations can be used with any new theory, provided the observational data and the reduction techniques are known.
C. Asinius Pollio and theEclogues
Authors: Cairns Francis
Published: June 2019

1. The addressees/honorands of the Eclogues

TheEcloguesare universally regarded as a highly structured literary artefact, and some scholars believe that Virgil'ssumma manusmodified the contents of individual poems at the book's final stage to achieve balance and symmetry. Whether or not such modification took place, the pattern of addressees/honorands in the collection – where they exist – ought to have some significance. The following table sets them out:

1.

deus(7) =iuuenem(42), usually identified as Octavian

2.

None

3.

C. Asinius Pollio (84–9)

4.

C. Asinius Pollio (esp. 11–14)

5.

None

6.

P. Alfenus Varus (6–7); C. Cornelius Gallus (64–73)

7.

None

8.

tu(6–13), often identified as C. Asinius Pollio, but by some as Octavian

9.

P. Alfenus Varus (26–9); L. Varius Rufus and C. Helvius Cinna (35–6); (?)‘Caesar’ (cf.Dionaei … Caesaris astrum, 47–9)

10.

C. Cornelius Gallus (passim)
Second Thoughts on Longus's Second Thoughts
Authors: Young Douglas
Published: June 2019

Though several leading Greek scholars expressed agreement with my theory (PCPS N.S. XIV (1968), 65–74) that our bifid manuscript tradition of Longus derives from two recensions by Longus himself, I had not expected it to go unchallenged, especially as the lecture in which I set it out necessarily could not explain in detail many passages of which the sense is not immediately apparent. Therefore I welcome Mr M. D. Reeve's detailed criticisms (PCPS N.S. XV (1969), 75–85). I am confident that, given space, I could refute all his objections; but I confine these remarks to a few by way of examples.

In the first passage that Mr Reeve discusses (p. 76), II.19.1, we may examine closely the author's earlier draft, as I think it, reflected in the manuscript A (Laurentianus, Conventi soppressi 627). It runs, with my punctuation:

Yet the affair had not altogether ended. But the men from Methymna, returning with difficulty to their own city, wounded, while the local inhabitants were luxuriating and being at ease, supplicated them to come to their help, and convened an assembly of the citizens, and, proffering suppliants' olive-branches, supplicated to be thought worthy of revenge.
Effect of supplementation and stage of growth on the partitioning of nutrients by Hereford x Friesian steers fed on grass silage based diets
Authors: Scollan N.D. , Cooper A. , Dhanoa M.S. , Wright M. , Dawson J.M. , Buttery P.J.
Published: June 2019

Forage based feeding systems are often disadvantaged compared with those based on high cereal usage in terms of feed intake, live weight gain and efficiency of utilisation of dietary energy and protein. Furthermore, under some situations, particularly with animals fed on grass silage, cattle often have higher fat:protein carcass ratios than those fed other forage-diets. However, other factors such as age, genotype and physiological state may also influence nutrient partitioning. An experiment was conducted to investigate the effect of diet (based on silage alone or supplemented with additional energy and/or protein) and stage of development on the partitioning of nutrients between fat and lean deposition. Overall effects of diet on animal performance and carcass composition were reported by Scollan et al. (1999).