bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dental diseases, malformations and malpositions studied by the Twin-Clinical Method
Authors: Gedda L. , Brenci G. , Pierelli F. , Parisi P. 
Published: July 2016

SUMMARYThe Twin Clinical Method (Gedda, 1963) has been applied to the study of dental pathology. Four cases of MZ female twin pairs have been studied, concordantly affected by dental agenesis (case I), mirror-imaging dental agenesis (case II), diastema (case III), and dental caries and enamel dystrophy (case IV). The test has also been applied, and for the first time, to a set of MZ female triplets, concordantly affected by dental caries and malposition.In all the above cases, the test has permitted to reject hypothesis of a concordance being due to chance, while postulating the existence of a causality.The latter is ascribed to the common heredity characterizing MZ cotwins.
Probability of monozygosity on the basis of incomplete serological analysis
Authors: Vrydagh-Laoureux S. 
Published: July 2016

SUMMARYWhen the result of the reaction to an antiserum is known for only one twin, it is nevertheless possible to calculate the probability that the twins be monozygotic, making allowance for that partial result.The probability of monozygosity is calculated in the hypothesis of complete concordance.This too high probability is then combined with the probability of concordance between sibs for the trait considered.
Some Applications of Model Atmospheres
Authors: Bessell M. S. 
Published: July 2016

In the five years since the last invited paper on model stellar atmosphere applications there have been many significant advances made on all fronts. The five aspects which I will cover in this paper are:
(1) the results of white dwarf model atmosphere investigations;(2) the results of the inclusion of non LTE phenomena in the atmosphere computations of hot (T > 15,000 K) stars;(3) the probable understanding of the cause of peculiar abundance patterns in the Ap and Bp and Am stars;(4) the advances in theory and observations of cool star atmospheres; and(5) the use of synthetic spectra and colours.
Active Phenomena in the Solar Atmosphere
Authors: Pikel’ner S.B. 
Published: July 2016

This paper gives a short description and interpretation of some solar magneto-hydrodynamical and plasma phenomena, based mainly on work by the writer and his collaborators (for an extended review see Kaplan et al. 1974).The magnetic field is considered as the main factor responsible for a number of manifestations of solar activity. At the photospheric level active regions are displayed as plages, i.e., bright areas, seen near the limb. This means that the temperature gradient in plages is smaller than in the undisturbed photosphere. The decrease in gradient is a result of an increase of convective transport of energy.
Globular Cluster Winds
Authors: Faulkner D.J. , Freeman K.C. 
Published: July 2016

Current evolutionary theory indicates that evolving stars in globular clusters arrive on the horizontal branch with ~30% less mass than they had on the main sequence. If, as seems likely, this mass loss results from the outflow of unprocessed material at the stellar surface during the giant stage, and if the ejected mass were retained within the cluster between successive sweeps through the galactic plane (~108 yr), sufficient hydrogen (100-2000 M⊙ should accumulate for detection. Radio searches, however, have failed to find evidence for either neutral or ionized gas. The hydrogen mass upper limits obtained by various workers are: Hills and Klein (1973) ionized H, 3.8 cm, <20-200 M⊙; Knapp, Rose and Kerr (1973) neutral H, 21 cm, <1-20 M⊙; Conklin and Kimble (1974) neutral H, 21 cm, <0.7-1.4 M⊙.We have extended the search into the optical region and have also calculated time-independent gas flow models to try to resolve this anomaly.
Formation Times for Rich Clusters of Galaxies
Authors: Lewis B. M. 
Published: July 2016

Rich clusters of galaxies are a common feature of the large-scale structure of the Universe. Those studied so far, show striking regularities with
(a)a smooth radial gradient of number density.(b)’isothermal’ distributions, which according to Bahcall (1975) have a scatter of only ±15% in the size of their characteristic core radii.(c)their limiting structural diameters are ~50 Mpc (cf. Abell, 1975), if they are identified with superclusters.(d)the magnitude of the velocity dispersion about their centres is generally 600-1000 km s-1, and the velocities are cpnsistent with a gaussian distribution (Yahil and Vidal, 1976; also Faber and Dressier, 1976).(e)The extreme velocities are generally within ±3000 km s-1, and for Coma are ∼2400 km s-1 (Tifft and Gregory, 1976).(f)elliptical galaxies tend to predominate near the centre, spirals in the surrounding loose groups.
Formation of the Satellite Systems of the Major Planets
Authors: Prentice A. J. R. 
Published: July 2016

It is well known that the satellite systems of the major planets Jupiter, Saturn and Uranus share many of the same regular features that can be seen in the planetary system of the Sun. The inner satellite orbits are nearly circular and lie in the plane defined by the axis of rotation of the central body. Again the distances Rn of the regular satellites, numbered inwards to the centre n = 0, 1, 2, …, form a nearly geometric sequenceRn/Rn + 1 ≌ constant,similar to the Titius-Bode law of planetary distances. These facts suggest that the same cosmogonic process must have been responsible for the origin of both types of systems.
A Search for OH Emission from Symbiotic Stars
Authors: Norris R. P. , Allen David A. , Haynes R. F. , Wright Alan E. 
Published: July 2016

SummaryA sensitive search has been made for OH maser emission from a sample of 16 symbiotic stars. This sample has been selected on the basis of infrared optical depth and variability, so that the stars within it have circumstellar shells similar to those seen in the well-known OH/IR and OH/Mira stars. There were no significant detections, except for one unassociated background source, and we conclude that the presence of a hot binary companion inhibits any possible OH maser action.
The FST-A 20 arc second Synthesis Telescope
Authors: Jones I. G. , Watkinson A. , Egau P. C. , Percival T. M. , Skellern D. J. , Graves G. R. 
Published: July 2016

AbstractThe baseline of East-West array of the Fleurs Synthesis Telescope (FST) has been extended from 786 metres to 1585 metres by the addition of two 13.7 metre dishes. A digital receiver has been built to accommodate the extra delay and correlation requirements, low noise FET preamplifiers have been installed on the large antennas, and a software package has been developed for processing observation data on a VAX 11/780. The FST is now capable of producing accurate wide field maps at 1415 MHz with a resolution of 20 arc seconds and a sensitivity of several milliJansky.
A Study of the Rapidly Rotating Variable Star HD 36705 (AB Doradus)
Authors: Innis J. L. , Robinson R. D. , Coates D. W. , Thompson K. 
Published: July 2016

AbstractPhotoelectric B and V light curves and high dispersion spectroscopic observations were obtained in 1985 February for the rapidly rotating spotted star HD 36705. The visual light range was about 0.09 magnitude, with a well correlated B-V change of approximately 0.04 magnitude, the star being redder when faintest. There is evidence for a broadband flare of ~0.05 magnitude in V and 0.07 magnitude in B. This occurred near maximum light.Spectroscopic observations show a variation in the equivalent width of the Ca K emission by a factor of about two in antiphase with the photometric variations, maximum emission corresponding to minimum brightness. This is probably due to bright plages and enhanced chromospheric heating associated with the photospheric starspots.High dispersion, high signal-to-noise spectroscopic observations confirm the presence of lithium λ 6708 as reported by Rucinski (1982, 1985).Several interpretations of the nature of HD 36705 are discussed; however at present none is completely satisfactory and further observations are required. As the star is probably at less than 100 pc, a parallax determination may be possible, and could help answer many of the questions concerning HD 36705.
Interstellar Nal Absorption Towards the Stellar Association Ara OB1
Authors: Whiteoak J. B. , Gardner F. F. 
Published: July 2016

AbstractObservations have been made of the interstellar D-line absorption of Nal towards a loose grouping of OB stars (containing the association Ara OB1 and probably the Hα emission regions RCW 107 and 108) centred at 1 = 337°.5 and b= -0°.5. The individual absorption spectra contain several velocity components which show well-defined groupings at –37, –18 and 0 km s-1. The corresponding median optical depths are 2, 7 and 6. The evidence indicates that both the –37 and –18 km s-1 Nal clouds are located in the Carina-Sagittarius spiral arm. Several HII regions are located at similar longitudes, but most are close to zero latitude and are more distant than the arm.The association contains the galactic cluster NGC 6193. The results suggest that the turbulence seen optically towards this cluster has been caused by the interaction between two cloud groups moving towards each other at velocities of 10 to 15 km s-1.
Sky Brightness and Atmospheric Extinction at A.N.R.A.O., Parkes and Siding Spring Observatory
Authors: Payne Paul 
Published: July 2016

AbstractIn May 1984 site testing began for the Automated Patrol Telescope. A series of atmospheric extinction and night sky brightness measurements were made over the following year at Parkes and Siding Spring Mountain using B and V filters. Parkes revealed an extinction greater than that of Siding Spring and more prone to variation. Results for the night sky brightness indicated Parkes has a sky slightly brighter than that at Siding Spring. The paper discusses the procedures used for obtaining the results and their limitations.
An Australian Broad-band Satellite for X-ray Astronomy
Authors: Greenhill J. G. , Fenton K. B. , Sood R. K. , Tuohy I. R. 
Published: July 2016

AbstractA broad-band (2-190 keV) Australian X-ray satellite could provide a spectral sensitivity substantially better than HEAO-1 or any presently approved spacecraft. It would be virtually unique by providing simultaneously data over a wide energy range with high sensitivity and energy resolution in the little measured region above 30 keV. These measurements are vital to our understanding of such diverse topics as the cyclotron line production mechanism in binary sources, the structure of the magnetosphere of neutron stars, the origin of the diffuse cosmic X-ray background and the nature of the giant power sources in active galaxies and stellar black holes. Details of the proposed spacecraft and scientific objectives are given.
Preferred Horizontal Scale for Thermal Convection
Authors: Fiedler R. , Murphy J. O. 
Published: July 2016

AbstractLinear stability theory for Rayleigh-Benard convection shows that for a specified Rayleigh number, greater than some critical value, only a finite range of horizontal wave numbers support convective instability in a horizontal layer of fluid heated from below. However, it is not possible to predict the preferred horizontal scale of established motions from this approach although it is clear from observations, particularly of the solar surface, that a preferred cell size does prevail. In an endeavour to establish a preferred horizontal scale appropriate non-linear modal equations have been integrated forward in time, initially incorporating a discrete band of wave numbers equally spaced across the range that supports convection, for a specific Rayleigh number. The horizontal resolution was improved in subsequent integrations by first deleting modes that had substantially decayed and then introducing new modes on a finer horizontal mesh in the vicinity of what appeared to be the evolutionary dominant mode. Finally, the multimode integrations were continued in time until the evolution of a dominant horizontal mode from within the restricted range was evident. Both the model characteristics and numerical scheme adopted placed limits on the degree of horizontal refinement that could be undertaken with confidence.
The Source of Free Energy for Type II Solar Radio Bursts
Authors: Cairns Iver H. 
Published: July 2016

AbstractA theory for the source of free energy for the Langmuir waves producing Type II bursts is presented. It is shown that electrons accelerated at the Type II shock naturally develop a distribution function with an abrupt cutoff at a characteristic minimum parallel velocity (a ‘cutoff distribution) in a limited spatial volume ahead of the shock, irrespective of the acceleration process active at the shock. The long duration, narrow bandwidth Type II radiation is then explained in terms of Langmuir waves produced by a cutoff distribution. The theory also accounts in a natural way for split-band Type II bursts and herringbone bursts.
The Parkes Radio Telescope — 1986
Authors: Ables J. G. , Jacka C. E. , McConnell D. , Schinckel A. E. , Hunt A. J. 
Published: July 2016

AbstractThe Parkes radio telescope was commissioned in 1961, with an anticipated operational life of 15 years. Twentyfive years later the telescope has been refurbished with the aim of extending its life yet another decade or two. A major undertaking has been the complete replacement of the drive and control System. This presentation outlines the main features of the new System and its effect on the observing facilities offered at the observatory.
The Solar-stellar Connection: Magnetic Braking and Stellar Activity
Authors: Mestel L. 
Published: July 2016

AbstractThe theory of coronal structure and of the associated angular momentum transport by magneto-thermo-centrifugal winds is reviewed, with reference to recent observations of rapidly rotating late-type stars. In particular, the combined optical and X-ray studies of AB Doradus are consistent with the predicted picture of a hot, magnetically-controlled ‘dead zone’ in near corotation with the star, and of cooler wind-emitting regions (analogues of the solar coronal holes). The standard theory predicts a rate of angular momentum transport that depends on the extent of the wind zone, the relative importance of thermal and centrifugal driving, and the variation of the dynamo-built surface field with rotation. For stars like the Sun, with approximately one tenth of the mass in the convective envelope, detailed comparison of the theory with the observed rotations of stars in clusters of different ages is sensitive to the strength of the coupling between the envelope and the radiative core, and is constrained by helioseismological limitations on rotational shear within the present-day Sun. An inferred strong braking during the early epochs may hint at a non-standard braking model, with the Maxwell stresses dominant far from as well as near the stellar surface.
The Effect of Helium Shell Flashes on Asymptotic Giant Branch Evolution
Authors: Vassiliadis E. , Wood P.R. 
Published: July 2016

AbstractMass-loss has been incorporated into a series of evolutionary calculations of low to intermediate mass stars during Asymptotic Giant Branch (AGB) evolution. When helium shell flashes occur a superwind phase is a natural consequence of the mass-loss process. The structure of the stellar wind envelopes that result has been computed. The models may explain some previously curious features seen in OH/IR and CO line emission spectra.
Energy Dissipation due to Mass Loss in a Rotating System
Authors: Melrose D.B. 
Published: July 2016

AbstractWhen a rotating magnetised system (angular speed Ω), such as a planet or star, loses mass there is necessarily an energy dissipation associated with the mass loss. Consider mass loss at rate M, such that the matter is flung off with the orbital speed ΩR1, at a radius R1 ≫ R0, where R0 is the radius of the planet or star. The power released is approximately equal to the power Prot = 1/2MΩ2R2 carried off in rotational kinetic energy. Part of the energy released is carried off as magnetic energy in the escaping plasma, and the remainder is released through dissipation of currents. Such dissipation plausibly leads to the acceleration of particles. The power released should be important for Jupiter and for some rapidly rotating stars. For most stellar systems, the power released is small compared to that required to drive a wind.
A Model for Intermediate Temperature Solar Coronal Loops
Authors: Brown S.F. 
Published: July 2016

AbstractSimple hydrostatic equilibrium models have been very successful at describing the physical conditions in hot coronal loops (T > 106 K). However, equilibrium models of cooler loops predict densities that are much lower than observed. We follow the evolution of a hot loop which undergoes a sudden reduction in heat input. The physical conditions in the cooling loop show significant departures from equilibrium. Such models appear to be able to reproduce the physical conditions observed in intermediate temperature loops (105 < T < 106 K).
Proxy Data from Tree-ring Time Series for the Eleven-year Solar Cycle
Authors: Murphy J.O. , Veblen T.T. 
Published: July 2016

AbstractOver past decades many attempts have been undertaken to detect a statistically significant 11-year variation in tree-ring widths and thereby provide direct evidence for the influence of solar cycle activity on growth. The data were generally associated with arid sites and were found to contain no signal of any consequence at the equivalent frequency. However, our recent analysis of a tree-ring chronology established from spruce trees growing at a very high sub-alpine site in Colorado, has revealed the presence of a dominant 11-year spectral periodicity over the last 200 years. These growth cycles could arise from temperature changes due to variations in insolation and climate or from variations in direct radiation within a specific band.
Redesigning a Baker-Nunn Camera for CCD Imaging
Authors: Carter B. D. , Ashley M. C. B. , Sun Y-S. , Storey J. W. V. 
Published: July 2016

AbstractThe University of NSW’s Automated Patrol Telescope is a modified Baker-Nunn satellite tracking camera, now used for CCD imaging of astronomical objects. The f/1 Baker-Nunn optical design gives a 30° field of view with an approximately spherical focal surface of radius ≈500 mm. While the focal plane curvature is tolerable across the 1.4° × 1.0° field of the present CCD, it becomes unacceptable when a larger CCD is used. In addition, the use of glass filters in the highly convergent beam produces intolerable spherical aberration. We present a design modification to the original Baker-Nunn which enables a 5° diameter flat field to be produced when using B, V, R or I filters. By making this modification, we plan to perform multicolour imaging, using a new large-format CCD with a 2.9° × 1.9° field of view.
The Laboratory Astrophysics Facility at University College
Authors: Hyland A.R. , Smith R.G. , Robinson G. 
Published: July 2016

AbstractA laboratory astrophysics facility for the study of the terrestrial analogues of interstellar dust grains is being developed in the Physics Department, University College, Australian Defence Force Academy. The facility consists of a gas handling system for the preparation of samples, a closed-cycle cooler and specimen chamber, and a Fourier Transform Infrared (FTIR) Spectrometer capable of high resolution (0.3 cm−1) and high sensitivity measurements, currently from 1-25 μm. The layout and construction of the laboratory are described, and the proposed initial experimental program aimed at determining the optical constants of ices over a wide wavelength range for comparison with astronomical observations is discussed.
Towards a Unified Model of Active Galactic Nuclei
Authors: Coleman C.S. , Dopita M.A. 
Published: July 2016

AbstractActive Galactic Nuclei (AGN) occur with widely differing characteristics of luminosity, variability and non-thermal emission. Although it is generally accepted that all such objects are powered by the accretion of matter to a super-massive black hole, no convincing model has been proposed which accounts for the diversity of observed phenomena. The model described here is based upon the hypothesis that shear flows in a misaligned accretion disc around a Kerr black hole lead to the growth of dynamical instabilities which disrupt the disc near the Bardeen-Petterson radius. Resulting clouds of disc material are fragmented by collisions and ablated by radiation from the compact core to produce a hot Parker wind which is optically thick to electron scattering. Within this wind, many fragments of disc material are entrained and photoionised to produce the broad emission lines, while some are accreted to power the system. Usually the wind impedes jet flows, in which case the object is radio quiet. When the disc and black hole are only slightly misaligned, however, the wind is equatorially biased and collimated axial jets may form. Such objects will be radio loud, and may exhibit superluminal phenomena if the jet is oriented close to the line of sight.
A New Infrared Camera Optical Design
Authors: Sun Y-S. , Ashley M.C.B. , Storey J.W.V. 
Published: July 2016

AbstractWe have designed a novel all-reflective optical system for an infrared camera. The camera gives a flat 5 arcminute field with a final focal ratio of f/2.5 when used at the f/15 focus of the Anglo-Australian Telescope (AAT). A 70mm diameter Fabry-Perot filter can be accommodated in a collimated beam, thereby giving narrow-band imaging capability. The design could readily be adapted to other telescopes and focal ratios. Its advantages are no chromatic aberration, no vignetting, no ghost images, low light-loss and excellent image quality.
Solar Radio Astronomy at the University of Western Australia, 1946-48
Authors: Burman R.R. , Jeffery P.M. 
Published: July 2016

AbstractA small radio astronomy group led by S.E. Williams in the Department of Physics at the University of Western Australia operated in the pioneering days. Observations were made of solar radiation at 75 Mc/s (4 m), using a polar-mounted Yagi antenna on the University campus in the Perth suburb of Nedlands. The group produced four papers, three in Nature and a longer one published locally. Although the work was noticed internationally, its influence on the course of radio astronomy seems to have been slight, and even the existence of the group has been almost forgotten outside of its home department.
An Automatic Electronic Combined Blink-comparator and Measuring Engine
Authors: Thomas G. , Jones E. , Jones K. L. , Francis G. M. , Kingshott F. , O’Mara B. J. , Page A. A. 
Published: July 2016

AbstractWe have designed and manufactured a multi-purpose electronic, computer-operated blink-comparator and measuring engine. It has been specifically designed to facilitate the examination of stellar images on Uppsala Schmidt photographic plates, identify and establish coordinates of new suspect variable stars appearing on the plates being examined, and also to derive photometric values for those stars manifesting variability.
The Head—Tail Radio Galaxy B1610—605
Authors: Jones Paul A. , McAdam W. Bruce 
Published: July 2016

AbstractThe radio galaxy B1610–605 within the Abell cluster A3627 has a low-brightness tail extending at least 26 arcmin from the nucleus of the 14 · 5m galaxy. The structure of this tail has been explored using observations with the Molonglo Observatory Synthesis Telescope (MOST) and the Australia Telescope Compact Array (ATCA). We present details of the brightness, width and alignment of the tail. The single tail expands and brightens rapidly within 2 arcmin of the nucleus. Confinement by the pressure of the cluster medium maintains a low but constant brightness for the tail between 10 and 25 arcmin. There are indications of turbulence down the tail but the position of the ridge remains within 1 · 6 arcmin of the initial alignment throughout its length.