bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of Fertility and Fecundity of Sheep by Means of Hormonal Manipulation
Authors: Scaramuzzi RJ , Downing JA , Campbell BK , Cognie Y
Published: November 2018

The results of four experiments are presented in summary form. The data are considered in relationship to the improvement of the fecundity and fertility of the Australian ewe breeding flock. In the first, three commonly used methods of oestrous synchronization were examined and showed differences that are attributed to the different patterns of hormonal changes associated with the methods demonstrated. The second experiment looked at the use of active immunization against testosterone and concluded that this method can improve fecundity but not fertility. The third experiment, a group of five trials, studied the use of progestagen sponges and PMSG in anoestrous ewes as a means of inducing normal fertility. The extensive data produced in this experiment allowed the relationships between ovulation rate and fertility and between fertility and prolificacy (fecundity) to be examined. Fertility appeared greatest when the mean flock ovulation rate was about 2�5. At this ovulation rate prolificacy was also improved and a high proportion of twins were produced. We concluded that high fertility and low prolificacy (i.e. of 1�00) are an unlikely combination. In the final experiment the effect of post-mating hormonal supplementation on fertility was examined and a number of earlier reports were confirmed by showing that fertility can be improved with supplementary progesterone between days 10 and 25 post-mating. The effect appears to be modified by hormonal and nutritional factors.
The Proposed Use of Melatonin in Controlled Sheep Breeding
Authors: Poulton AL
Published: November 2018

The regulation by melatonin of hypothalamic-pituitary events in the ewe to advance seasonal oestrous activity, with no undesirable effects upon fertility, and its induction of those seasonal responses associated with short days indicates an essential role for melatonin in controlled-breeding programs in major sheepproducing countries. The development of suitable controlled-release systems to provide a choice of practical methods of melatonin delivery under field conditions is discussed as also are geographical and breed factors in controlled breeding with melatonin.
Transcriptome profiling of soybean root tips
Authors: Haerizadeh Farzad , Singh Mohan B. , Bhalla Prem L.
Published: November 2018

Soybean (Glycine max L.), a major legume crop, is important to human nutrition and is a source of animal feed. Similar to many legumes, a key feature of the soybean is its symbiotic association with soil bacteria that fix atmospheric nitrogen. However, knowledge of the gene expression of its root system, particularly the root meristematic region, is limited. Here, we have addressed this by investigating the gene expression profile of the soybean root tip, using soybean Affymetrix chips containing 37 500 probe sets (Affymetrix Inc.) and have compared this expression profile with that of the nonmeristematic tissue. We identified a total of 5012 upregulated and 4136 downregulated genes in the soybean root tip. Among the upregulated genes, 559 showed strong preferential expression in the root tip, indicating that they are likely to be associated with root apical meristem specificity and root tip function. Genes involved in membrane transport, defence signalling and metabolism were upregulated in the soybean root tip. Further, our data provide a resource of novel target genes for further studies involving root development and biology, and will possibly have a positive impact on future crop breeding.
Revisiting the role of organic acids in the bicarbonate tolerance of zinc-efficient rice genotypes
Authors: Rose Michael T. , Rose Terry J. , Pariasca-Tanaka Juan , Widodo  , Wissuwa Matthias
Published: November 2018

It has been hypothesised that enhanced organic acid release from the roots of zinc-efficient rice (Oryza sativa L.) genotypes plays a strong role in plant tolerance to both bicarbonate excess and Zn deficiency. To address several uncertainties in the literature surrounding the tolerance of rice to bicarbonate, we initially assessed the tolerance of six rice genotypes to bicarbonate stress under field conditions and in solution culture. The landrace Jalmagna and its recombinant inbred offspring, RIL46, consistently performed better in terms of maintenance of biomass and root length under high bicarbonate concentrations. In the hydroponic experiments, increased root malate (but not citrate) accumulation and efflux were responses to high solution bicarbonate in the short-term (12 h) in all genotypes. Although both citrate and malate accumulation and efflux increased after long-term exposure (10 days) to high bicarbonate and Zn deficiency, it coincided with amino acid leakage from the roots. Partial least-squares regression showed that this leakage consistently ranked highly as an indicator of poor plant health under all stress conditions, whereas specific malate efflux (the ratio of malate to amino acid efflux) was an important predictor of good plant health. The root leakage of Zn-inefficient genotypes under bicarbonate and dual stress (bicarbonate with low Zn) was typically higher than in Zn-efficient genotypes, and coincided with higher peroxide concentrations, suggesting that bicarbonate tolerance is related to the ability of Zn-efficient genotypes to overcome oxidative stress, maintain root membrane integrity and minimise root leakage.
Impact of arbuscular mycorrhizal fungi (AMF) on cucumber growth and phosphorus uptake under cold stress
Authors: Ma Jun , Janoušková Martina , Li Yansu , Yu Xianchang , Yan Yan , Zou Zhirong , He Chaoxing
Published: November 2018

Symbiosis with root-associated arbuscular mycorrhizal fungi (AMF) can improve plant phosphorus (P) uptake and alleviate environmental stresses. It could be also an effective mean to promote plant performance under low temperatures. The combined effects of arbuscular mycorrhiza and low temperature (15°C/10°C day/night) on cucumber seedlings were investigated in the present study. Root colonisation by AMF, succinate dehydrogenase and alkaline phosphatase activity in the intraradical fungal structures, plant growth parameters, and expression profiles of four cucumber phosphate (Pi) transporters, the fungal Pi transporter GintPT and alkaline phosphatase GintALP were determined. Cold stress reduced plant growth and mycorrhizal colonisation. Inoculation improved cucumber growth under ambient temperatures, whereas under cold stress only root biomass was significantly increased by inoculation. AMF supplied P to the host plant under ambient temperatures and cold stress, as evidenced by the higher P content of mycorrhizal plants compared with non-mycorrhizal plants. Thus, the cold-stressed cucumber seedlings still benefited from mycorrhiza, although the benefit was less than that under ambient temperatures. In accordance with this, a cucumber Pi transporter gene belonging to the Pht1 gene family was strongly induced by mycorrhiza at ambient temperature and to a lesser extent under cold stress. The other three Pi transporters tested from different families were most highly expressed in cold-stressed mycorrhizal plants, suggesting a complex interactive effect of mycorrhiza and cold stress on internal P cycling in cucumber plants.
Intraspecific variation in drought susceptibility in Eucalyptus globulus is linked to differences in leaf vulnerability
Authors: Lucani Christopher J. , Brodribb Timothy J. , Jordan Greg , Mitchell Patrick J.
Published: November 2018

Understanding intraspecific variation in the vulnerability of the xylem to hydraulic failure during drought is critical in predicting the response of forest tree species to climate change. However, few studies have assessed intraspecific variation in this trait, and a likely limitation is the large number of measurements required to generate the standard ‘vulnerability curve’ used to assess hydraulic failure. Here we explore an alternative approach that requires fewer measurements, and assess within species variation in leaf xylem vulnerability in Eucalyptus globulus Labill., an ecologically and economically important species with known genetic variation in drought tolerance. Using this approach we demonstrate significant phenotypic differences and evidence of plasticity among two provenances with contrasting drought tolerance.
Plant phenome to genome: a mini-review
Authors: Appels Rudi
Published: November 2018

Rapid advances in biotechnologies have provided a template for defining the genome–transcriptome–proteome in many plant species and these advances now highlight a particular challenge to link the molecular biology–based studies to changes in the phenome of plant species. Selected examples are provided to review advances in defining environment–phenotype interactions, the genome–transcriptome–proteome in plants and translating research outputs more broadly to society. The specific examples include computer modelling of plant phenotypes and responses to environmental signals, advances in small molecule signal transduction, visualising macromolecules and defining the complex genomes that are important to society. The need to translate research outputs to society more broadly is also discussed.
Behaviour of the Kramer Radiating Star
Authors: Maharaj S. D. , Govender M.
Published: November 2018

We study the behaviour of the model for a radiating star proposed by Kramer.
The evolution of the model is governed by a second order nonlinear
differential equation. The general solution of this equation is expressed in
terms of elementary and special functions. This completes the solution of the
Einstein field equations for the interior of the star. The model matches
smoothly to the Vaidya exterior solution and the condition
p = qB is satisfied at the boundary. We briefly study
the thermodynamics of the model and indicate the difficulty in specifying the
temperature explicitly.
Effects of Boundary and Electron Inertia on the Ion Acoustic Wave in a Plasma: A Pseudopotential Approach
Authors: Mondal K. K. , Paul S. N. , Chowdhury A. Roy
Published: November 2018

A pseudopotential approach is used to analyse the propagation of ion-acoustic
waves in a plasma bounded by a cylindrical domain. The effect of the finite
geometry is displayed both analytically and numerically. The phase velocity of
the wave is determined and its variation is studied with respect to the plasma
parameters. It is observed that the pseudopotential shows a wide variation of
shape due to the imposition of a finite boundary condition. It is shown that
if the other parameters are kept within a certain range of values, then the
trapping of particles is favoured when the presence of the boundary is taken
into account.
Structure of the World Crystal
Authors: Agop M. , Griga V. , Buzea C. Gh. , Rezlescu N. , Buzea C. , Zacharias A. , Petreus I.
Published: November 2018

Identifying space with a superconducting cosmic dust, the structure of the
‘world crystal’ is built. Particles moving on open geodesics are
assimilated with the ‘electron gas’ in a lattice, and those moving
on closed geodesics with nodes of the same lattice. By considering that this
kind of structure may be achieved by pinning on a background gravitomagnetic
field, the properties of such fields are studied. From this analysis and
computing the background energy we are lead to a Cantorian-fractal structure
of space–time, which allows one to interpret the gravitational
interaction in terms of a mechanism similar to the composite fermions
mechanism.
How to write a paper for successful publication in an international peer-reviewed journal.
Authors: Tress Gunther , Tress Barbel , Saunders Denis A
Published: November 2018

In this paper, we present a step-by-step guide on how to write a paper for successful publication in a peer-reviewed journal. We propose a ten-step approach to the entire process of paper writing from preparation, manuscript writing, and submission to the stages of peer-review and revision. The steps include defining paper objectives, authorship, journal selection, writing routines, requirements of manuscript sections, editing and proof-reading as well as how to communicate successfully in submission and review.
Reptile Euthanasia — No Easy Solution?
Authors: Warren Dr Kristin
Published: November 2018

Reptiles are commonly studied in biological research projects, and wildlife researchers may be required to euthanize
a reptile if it sustains a severe injury associated with the research. When conducting euthanasia of any animal it is
critical to confirm death. Whilst in mammals and birds euthanasia and confirmation of death can easily be accomplished,
in reptiles these are not straight forward processes due to reptilian poikilothermic biology and physiology. Many
traditional methods of reptile euthanasia are controversial, and recommended methods of acceptable euthanasia vary
amongst the different reptilian orders. Physical methods of euthanasia involving hypothermia or decapitation alone are
considered inhumane and are not acceptable methods of euthanasia. Injectable pentobarbitone sodium is considered
an acceptable method of euthanasia for all reptiles, except large crocodiles and other large reptile species where carcass
removal in the wild may be problematic. However, in Australia pentobarbitone sodium is a Scheduled 4 drug with
requirements for locked storage, and users other than registered veterinarians must apply for authorization to administer
scheduled drugs. Stunning followed by destruction of the brain is considered acceptable with reservations in some
small species of snakes and lizards, where these methods can be effectively accomplished. MS222 has been used in
several species of reptiles, however further research is required to determine whether this technique is effective and
humane across the diverse range of reptilian species. Humane euthanasia in reptiles is not easily achieved and, whilst
recognizing limitations in accessing veterinary anaesthetic and euthanasia drugs, it can best be assured by using a
two-stage euthanasia process — whereby the reptile is initially anaesthetized, and then euthanized by administration
of pentobarbitone sodium or alternatively a combination of decapitation and brain destruction following anaesthesia.
Euthanizing wildlife: experiences and coping strategies among people who conduct euthanasia.
Authors: Von Dietze Erich , Gardner Dianne
Published: November 2018

Researchers who work with animals commonly face the dilemma of euthanizing some animals. Euthanasia of
animals, especially where it concerns pest wildlife or feral species, is often a sensitive and emotive topic and can
raise vigorous public debate. However, little is known about the experiences of those who euthanize animals. This
study interviewed a number of people about their experiences of animal euthanasia in order to attain a better
understanding of any impacts on the person involved in the euthanasia. Participants were mainly researchers, including
some no longer working directly with animals and some who provide support services. The participants had a range of
experience in wildlife research, and veterinary practices as well as laboratory, farm, and animal shelters. Thematic
analysis was used to analyse qualitative interview data. Key emerging themes included the language used to describe
euthanasia, the coping strategies that individuals applied, and the organizational factors which could ensure an appropriate
context for researchers carrying out euthanasia. Participants reported that social support for emotional stress arising
from euthanasia was generally not available. Organizational factors which impacted on participants included decision
making processes, availability of training and support, work practices and justifications for euthanasia. The paper
concludes that it is important not to pathologize the experiences of researchers but to recognize that the way the decision
to euthanize is reached and the training it is based on can make a significant difference to a person’s attitudes and
levels of comfort when euthanizing animals.
No evidence for Galapagos Plasmodium lineage arriving via Humboldt Current seabirds.
Authors: Levin Iris I , Adkesson Michael J , Evans Maranda , Rettke Cindee K , Parker Patricia G
Published: November 2018

Avian malaria, caused by parasites in the genus Plasmodium, has recently been detected in the endangered
Galapagos penguin (Spheniscus mendiculus). Understanding possible routes of parasite and pathogen introduction is
important for management of small and isolated populations, because island populations can be at higher risk of adverse
effects due to lower immunity. One possible means of introduction could be through contact with pelagic birds from
coastal South America. In order to better understand the origins of Plasmodium in Galapagos penguins, we used a
PCR protocol to test for haemosporidian parasites in Humboldt penguins (Spheniscus humboldti), the sister species of
Galapagos penguins, and two other Humboldt Current endemics, the guanay cormorant (Phalacrocorax bougainvillii)
and the Peruvian pelican (Pelecanus thagus). None of these seabirds, all sampled at Punta San Juan, Peru, tested
positive for haemosporidian parasites. Although the strong Humboldt Current flows from Antarctica up the South American
coast and towards Galapagos at the equator, contact rates between these Humboldt endemics and Galapagos birds
might still be rare. Despite negative results, this information is important for furthering our knowledge of Plasmodium
in Galapagos and in our efforts to effectively manage wildlife diseases.
Indicators of coral reef ecosystem recovery following reduction in logging and implementation of community-based management schemes in the Solomon Islands.
Authors: Albert S , Grinham A , Gibbes B , Tibbetts I , udy J
Published: November 2018

The livelihood of many coastal communities in the Pacific Islands is directly dependent on the health of adjacent
coral reefs. Reduction in water quality and over-harvesting of herbivorous fish are known to drive reef ecosystems
towards a more degraded state. Community-based resource management practices have the potential to improve
damaged reefs but quantitative data on their effectiveness remains largely unreported. This study investigated how
land use changes and implementation of marine management influenced water quality, herbivorous fish biomass and
reef condition of Marovo Lagoon in the Solomon Islands. Four study sites were located along a gradient of water quality,
with two of the sites located inside marine protected areas (MPAs) designated in 2006. The results suggest that water
quality in coastal areas adjacent to catchments modified by logging was negatively impacted. However, following natural
revegetation of bare soil in the catchment between 2000 and 2010, water quality improved at all sites. The biomass of
herbivorous fish was significantly greater in the MPAs compared to other sites and, importantly, we detected an increase
in herbivore biomass between 2005 and 2008. Inshore reefs adjacent to logging operations had significantly lower coral
cover and higher macroalgal cover than those offshore. Between 2005 and 2008 all sites showed an increase in crustose
coralline algae cover and a decrease in turf algae colonising rocks, with the changes indicative of improving reef health.
Collectively, these results indicate that reduction in logging and implementation of community-based management can
have a positive influence on reefs in Marovo Lagoon.
Are wild rodents attracted to lure laboratory rats?
Authors: Gsell A C , Seabrook-Davison M N H , Brunton D H
Published: November 2018

invasions to New Zealand’s unique biodiversity, ‘pest-free’ offshore and mainland island refuges have been created.
The success of this approach depends on the long term maintenance of the pest-free status of these refuges. Because
the occurrence of rodent incursions is an on-going risk, early detection and elimination of invading animals is crucial.
We conducted field-based experiments to determine if lures of live female and male laboratory Norway rats (Rattus
norvegicus) held in cages in the wild, and lures consisting of urine-soaked rodent bedding could be used to detect the
presence of wild rodents. We found that the use of live rodents and bedding significantly increased the probability of
detecting wild rodents, although we were not able to determine the sex, age or number of wild rodents attracted to
each live rodent station. We also found that wild rats were equally attracted to the scent of male and female rats i.e.,
lures and bedding. Our approach provides potential as a tool for early detection of rodents in vulnerable refuges and
we suggest that further research is needed to investigate the feasibility of developing rat scented monitoring stations.
Microwave Absorption in Layered Media: Application to Landmine Detection
Authors: Hermann J. A.
Published: November 2018

The absorption of microwave radiation and subsequent thermal conduction by
simple composite media, consisting of parallel layers with disparate thermal
properties,is analysed.The solutions for a one-dimensional conduction model
are used to investigate the time evolution and distribution of thermal energy
within moisture-laden soils containing non-absorbing objects.The application
of these results to the detection of landmines is discussed and evaluated.
Influence of Inversion Symmetry on the Metallic Behaviour in a Dilute Two-dimensional Hole System
Authors: Hamilton A. R. , Simmons M. Y. , Pepper M. , Ritchie D. A.
Published: November 2018

In the past five years numerous experimental studies of a wide variety of low
disorder two-dimensional (2D) semiconductor systems have revealed an
unexpectedly large decrease in the resistance as the temperature is lowered
from T ~ 1 K, suggesting the existence of a 2D
metal. Although numerous theories have been put forward to explain this
metallic-like behaviour (which contradicts the expectations of one parameter
scaling theory), its origins, and the question of whether it persists to
T = 0, are still subjects of great debate. We
present a detailed study of the influence of inversion symmetry on the
B = 0 metallic behaviour in a low density GaAs
hole gas close to the apparent two-dimensional metal—insulator
transition. The strength of the metallic behaviour (determined by the size of
the drop in resistance as T→ 0) is found to be
almost independent of the electric field across the hole gas, and is
predominantly determined by the magnitude of k
F l at low temperatures (i.e. by
the low temperature resistivity). These results suggest that the shape of the
potential well and spin—orbit effects alone cannot account for the
existence of metallic behaviour in low density, strongly interacting 2D
systems.
Voltage Response of AC Susceptibility and Pinning Effects in Hg0.69Pb0.31Ba2Ca2Cu3O8+δ
Authors: Tang Y. L. , Shen L.J , Lu D. W. , Hung K.C , Jin X. , Xuu X. X. , Shao H. M. , Lam C. C. , Shen L. J. , Hung K. C.
Published: November 2018

We have studied the voltage response of AC susceptibility,and from the
imaginary part of the susceptibility experimental results a new method is
presented in terms of the material equation to investigate the pinning
properties and the dynamical response in our Hg 0.69 Pb
0.31 Ba 2 Ca
2 Cu 3 O
8+δ sample. We also discuss the differences
between the voltage criterion and our AC response measurement method in order
to determine the value of the true critical current density. The result shows
that the later method reflects the true critical state of high-temperature
superconductivity better than the general voltage criterion.
‘Anomalous’ Resurgence of Shot Noise in Long Conductors
Authors: Das Mukunda P. , Green Frederick
Published: November 2018

There has been renewed interest in the physics of the so-called
‘crossover’ for current fluctuations in mesoscopic conductors,
most recently involving the possibility of its appearance in the passage to
the macroscopic limit. Shot noise is normally absent from solid-state
conductors in the large, and its anomalous resurgence there has been ascribed
to a rich interplay of drift, diffusion, and Coulomb screening. We demonstrate
that essentially the same rise in shot noise occurs in a much less complex
system: the Boltzmann—Drude—Lorentz model of a
macroscopic, uniform gas of strictly non-interacting
carriers. We conclude that the ‘anomalous crossover’ is a
manifestation of simple kinetics. Poissonian carriers, if driven by a
high enough
field, cross the sample faster than any scattering time,
thus fulfilling Schottky’s condition for ideal shot noise.
Microscopic Model Analyses of the Elastic Scattering of 25, 30 and 40 MeV Protons from Targets of Diverse Mass
Authors: Deb P. K. , Amos K. , Karataglidis S.
Published: November 2018

An extensive survey and analysis of cross-section and analysing power data
from proton elastic scattering at energies 25 to 40 MeV is presented. The data
are compared with predictions obtained from a full folding specification of
the proton–nucleus optical potentials. Isotope and energy variation of
the data is explained.
Correcting for Gaussian Aerial Smoothing
Authors: Bracewell RN
Published: November 2018

Let a. two-dimensional survey with a Gaussian aerial beam establish values at intervals of standard deviations. Then the correction for aerial smoothing is simply calculated as the difference between the value to be corrected and the mean of the neighbouring four values.
The Gravitational Compression of an Elastic Sphere
Authors: Keane A
Published: November 2018

On considering a sphere in hydrostatic gravitational equilibrium, composed of a homogeneous elastic material for which the variation of incompressibility x with pressure p is given by dx/dp=n, a constant, we find that there is an upper bound to the radius R of the sphere provided n=2, and that for all values of n there is a lower bound to the value of I/MR2, where I is the moment of inertia about a diameter and M is the mass of the sphere.
Cosmic Rays and Air Mass Effects at Macquarie Island
Authors: Jacklyn RM
Published: November 2018

In a recent paper (Jacklyn 1954) it was shown that the barometer coefficient for cosmic rays at Macquarie Island varied consistently according to the type of air mass present over the station. This was found to be due to the different average values of (the rate of change of the height of the assumed production level for mesons with surface pressure) in the two air mass types considered.
The Accelerated Motion of Droplets and Bubbles
Authors: Pearcey T , Hill GW
Published: November 2018

The drag force acting upon small particles such as droplets and bubbles, moving through a viscous medium, depends upon the rate of change of the state of motion of the medium and upon the diffusion of vorticity from the surface' of the particle. For accelerated particles the drag force changes with time and depends upon all previous accelerations. The equation of motion of a particle takes the form of an integro-differential equation, which has been solved numerically in the case of deceleration to rest from uniform motion with no impressed body forces. In any experiments designed according to the principles of dynamical similarity, the ratios of viscosities and densities of the medium and the particle must be maintained constant in the scale transformations involved.
Growing Electric Space?Charge Waves
Authors: Piddington JH
Published: November 2018

A theory of growing space-charge electric waves, due to Pierce, Haeff, and others, is thought to explain the operation of Haeff's electron-wave tube and other amplifying devices and perhaps the origin of some solar radio emission. The theory is shown to be untenable, the growth predicted being spurious and due to misinterpretation of the dispersion equations.
Formulae for the Mean Losses of Energy in Collisions of Slow Electrons Moving in Diatomic Gases
Authors: Huxley LGH
Published: November 2018

Formulae are derived for the mean losses of energy in collisions with molecules by electrons moving in a steady state of motion in a diatomic gas in an electric field. Although the theory is incomplete and crude, yet the formulae describe the experimental measurements closely in the smaller ranges of electronic energy.
18?3 Mc/s Radiation from Jupiter
Authors: Shain CA
Published: November 2018

Burke and Franklin's discovery of radio emission from Jupiter has been confirmed. Examination of old records has shown that in 1950?51 the radiation came in groups of bursts of very high intensity. Bursts have durations of the order of a minute or less; groups, of an hour. Because of the remarkably close relation between active periods and the period of rotation of Jupiter, it is inferred that the source at the time was very localized. Its identification with a visual disturbance in the South Temperate Belt is very probable.
Cosmic Radio Sources Observed at 600 Mc/s
Authors: Piddington JH , Trent GH
Published: November 2018

A survey of cosmic radio emission at 600 Mc/s using a beam 3�� 3 wide has been made over most of the celestial sphere between declinations 90 �S. and 51 �N. Discrete sources numbering 49 were located having flux densities of about 1 � 10?24 W m?2 (c/s)?l or more. Of these, 18 do not appear to have been reported previously, including 12 which lie within �2� of the galactic plane.
Lunar Variations in the Ionosphere
Authors: Duncan RA
Published: November 2018

The global pattern of the observed lunar variations of the height and electron density of the F2 region is briefly summarized, new analyses being presented for Canberra (f0F2), Brisbane (h'F2), and Washington (h' and f0F2). It is concluded that the height variation has an amplitude of from 1 to 3 km and a phase giving maximum height at 06 lunar hours at moderate latitudes and at 09 lunar hours at the geomagnetic equator. The critical frequency variation has an amplitude of from 2 to 4 per cent., maximum critical frequency occurring at about 09 lunar hours at moderate geomagnetic latitudes and 04 lunar hours at equatorial geomagnetic latitudes.
Ionospheric Recorders and Sporadic E
Authors: Thomas JA , Svenson AC , Brown HE
Published: November 2018

It has been many times stated (Rawer 1949; Booker 1950; Booker and Gordon 1950; McNicol and Gipps 1951) that the frequency characteristics of the sporadic E region are rapidly varying functions of the overall sensitivity of the recording p'f equipment. A very simple test of this statement has been made; and it has been found to be incorrect at Brisbane.
The Function Inverfc ?
Authors: Phllip JR
Published: November 2018

The function inverfc 6 arises in certain diffusion problems when concentration is taken as an independent variable. It enters into a general method of exact solution of the concentration-dependent diffusion equation. An account is given of the properties of this function, and of its derivatives and integrals. The function
Sunrise and Eclipse Effects on the Ionosphere at Brisbane
Authors: Bowman GG
Published: November 2018

A rotating spaced.loop direction.finding system, located at Brisbane, has been operated to investigate sunrise effects by using pulsed 3�84 Mcls transmissions, (a) at normal incidence and (b) at oblique incidence. For oblique.incidence recording the transmitter was located at Armidale (bearing 2020 and distant 355 km from Brisbane).
A Relationship Between Spread-F and the Height of the F2 Ionospheric Layer
Authors: Bowman GG
Published: November 2018

The variation, throughout the night, of range-spreading spread-F widths, at Brisbane, is investigated. Evidence is presented to support the hypothesis that the ripple amplitude of the spread-F ionospheric irregularities varies directly with the layer height. This leads to an association between the range-spreading width and the height of the layer.
Attempts to Measure the Inductive Element Associated with the Natural Convection of Heat
Authors: Bosworth RCL
Published: November 2018

A study has been made of the variation in time of the temperature of a wire immersed in a fluid and heated by a constant electric current. For a given fluid the curve obtained by plotting the ratio of the temperature of the wire to the heat input versus the time is initially the same shape for all rates �of heat input. Divergences from the lowest heating rate set in only when the system of convection currents sets in. This occurs at earlier times after the commencement of heating the higher the heating rate. Expressions already developed are used to evaluate the resistive, capacitive, and inductive elements required to fit the observed transient curves. The values of the former two types of element are consistent with an assumed stagnant film of a thickness the order of 1 mm around the heated wire, but the value of the deduced inductive element is some 10--106 greater than that associated with the kinetic energy belonging to the system of convection currents.
A Swarm Experiment in He–H2 Mixtures to Examine Vibrational Excitation of H2 by Electron Impact
Authors: Petrovic ZLj , Crompton RW
Published: November 2018

Measurements of electron drift velocities have been made in pure helium and in a helium-hydrogen mixture in order to check the available inelastic cross sections for hydrogen. Although drift velocities in mixtures with helium as the buffer gas are less,sensitive to inelastic scattering by hydrogen than those with argon, the accuracy with which the momentum transfer cross section for helium is known enables the check to be made with virtually no error arising from uncertainty in the momentum transfer cross section for the buffer gas, in contrast to the situation when argon is used. A difference techrtique has been used to minimise the effect of systematic errors in the measurements. The results support the rotational and vibrational cross sections derived from the transport coefficients measured in pure hydrogen.
Evolution Equation and Transport Coefficients of Swarms in Initial Relaxation Processes
Authors: Kondo Keiichi
Published: November 2018

The problem of a swarm approaching the hydrodynamic regime is studied by using the projection operator method. An evolution equation for the density and the related time-dependent transport coefficient are derived. The effects of the initial condition on the transport characteristics of a swarm are separated from the intrinsic evolution of the swarms, and the difference from the continuity equation with time-dependent transport coefficients introduced by Tagashira et al. (1977, 1978) is discussed. To illustrate this method, calculations on the relaxation model collision operator have been carried out. The results are found to agree with the analysis by Robson (1975).
Interferometers, Aberration and the Sagnac Effect
Authors: Kesteven MJ
Published: November 2018

In this note we show that the usual expression for diurnal aberration (see e.g. Woolard and Clemence 1966) is not valid for some types of radio interferometers. The difference (usual minus correct) is a constant of the instrument, and is absorbed in the calibration procedure. The analysis of multibaseline VLBI may also be affected.
A Charged Analogue of the Vaidya?Tikekar Solution
Authors: Patel LK , S Koppar Sharda
Published: November 2018

We present here an interior solution of the Einstein-Maxwell equations for a charged static fluid sphere. The physical 3-space t = constant of the solution is spheroidal. The solution is interpreted as an exact relativistic model for a charged superdense star.
Which Potentials have to be Surface Peaked to Reproduce Large Angle Proton Scattering at High Energy?
Authors: Raynal Jacques
Published: November 2018

Corrections to the usual form factors of the optical potential are studied with a view to getting a better fit for proton elastic scattering at large angles on 40Ca at 497 and 800 MeV. When a real surface form factor is added to the central potential in the Schrbdinger formalism, the experimental data are as well reproduced as in the standard Dirac formalism. Coupling to the strong 3- collective state gives a better fit. The use of surface corrections to the imaginary Dirac potential also gives improved results. A slightly better fit is obtained by coupling to the 3- state with, at the same time, a weakening of these corrections. Further corrections to the potential do not give significant improvements.
The Momentum Transfer Cross Section for Krypton
Authors: Mitroy Jim
Published: November 2018

A form of modified effective range theory (MERT) has been used to analyse drift velocity data for both pure krypton and molecular hydrogen-krypton mixtures. The present momentum transfer cross section reproduces the data to within 4% for pure krypton and to within 1 �0% for the H2-Kr mixtures.
Thermal Expansion of InBi at Low Temperatures
Authors: White GK , Collins JG , Schirber JE
Published: November 2018

Linear thermal expansions from 2 to 80 K are reported for a single crystal of tetragonal InBi. In the more compressible direction, parallel to the tetrad axis, DCII is negative except between 6 and 10 K. In the harder basal plane, DC.L is positive. This unusual behaviour confirms earlier observations between 100 and 250 K. The volume coefficient is positive at all temperatures and leads to values of y - 1 for the Griineisen parameter above 4 K.
High Energy Electron Impact Ionisation of H(1s) in Coplanar Asymmetric Geometry
Authors: T Whelan Colm , Walters HRJ , Hansen J , Dreizler RM
Published: November 2018

Various effective charge approximations are explored for the high energy electron impact ionisation of H(ls) in coplanar asymmetric geometry, using a first order perturbative model. Our results are compared with other more sophisticated calculations and with experiment. It is found that effective charge prescriptions satisfying the requirement that, in the limit of zero ejection energy, the escaping electron sees the full nuclear charge while the scattered electron is totally screened, are unsuccessful. In contrast it is found that the Coulomb projected Born exchange approximation, where both electrons see the full nuclear charge, gives much better results. In general it reproduces the position and magnitude of the binary peak fairly well, although it is not so successful in the description of the recoil.
Lateral and Axial Magnetisation in the Inverse Faraday Effect for the Interaction of Waves in Plasma
Authors: Sarkar Susmita , Bera B , Khan Manoranjan , Chakraborty B
Published: November 2018

We evaluate the static lateral magnetisation from the inverse Faraday effect, due to a circularly polarised electromagnetic wave and either a high frequency longitudinal dispersive plasma wave (case 1) or an ion acoustic wave (case 2), all propagating in the same direction in an unmagnetised plasma. These two lateral magnetisations are found to be in opposite directions. For the interaction of 1�06 /lm circularly polarised electromagnetic radiation having a power flux 5x1016 Wm-2 and pulse width 5 ns in a plasma, in case 2 the induced transverse static magnetic field is about 0�0014 Wbm-2 ? In case I, this static field is about 0�0234 Wb m-2. In a quiescent cesium plasma the magnetisation is found to be insignificant in both cases. These theoretical investigations may help in the understanding of anomalous diffusion of plasmas in some problems, and in the explanation of solar prominences and other such astrophysical effects.
Lunisolar Atmospheric Tides. III
Authors: Brahde R
Published: November 2018

In two earlier papers (Brahde 1988, 1989) the atmospheric tide in Oslo (Norway) was studied using pressure data for 23 continuous years. In the present paper a similar study based on pressure data from Batavia (now Jakarta in Indonesia, latitude 6�08'S, longitude 106�45'E) is presented. The result is that the tidal wave caused by the lunisolar tide is represented by a one-day and a half-day oscillation with mean amplitudes of 0 �11 and 0�33 mb respectively. The amplitude spectrum reveals amplitudes of up to 1 mb of dynamiC origin. The 'thermal' tide is also studied and the connection between the thermal and dynamic effects is discussed.
Canterbury Ring Laser and Tests for Nonreciprocal Phenomena
Authors: Stedman GE , Bilger HR , Ziyuan Li , Poulton MP , Rowe CH , Vetharaniam I , Wells PV
Published: November 2018

An historic and simple experiment has been revitalised through the availability of supercavity mirrors and also through a heightened interest in interferometry as a test of physical theory. We describe our helium-neon ring laser, and present results demonstrating a fractional frequency resolution of 2�1x10-18 (1�0 mHz in 474 THz). The rotation of the earth unlocks the counterrotating beams. A new field of spectroscopy becomes possible, with possible applications to geophysical measurements such as seismic events and earth tides, improved measurements of Fresnel drag, detection of ultraweak nonlinear optical propert~es of matter, and also searches for preferred frame effects in gravitation and for pseudoscalar particles.
Studies Involving the Resonant Interaction of Laser Light with Atoms
Authors: MacGillivray WR , Standage MC
Published: November 2018

In this article, we review three areas of study in which the resonant interaction between atoms and laser radiation plays a central role. Firstly, coherent optical transients are discussed in which the direct observation of this interaction can be studied via the detection of the Rabi frequency in optical nutations. Secondly, the response of atoms to resonant radiation in an optical cavity leading to optical bistability and other effects is described. Finally, the new field of atom manipulation by resonant laser fields is introduced, in particular, the deflection of atomic beams. The underlying theoretical framework for the experiments performed is discussed, ranging from full quantum electrodynamic to semiclassical models.
Multiple Scattering Calculation for Ionisation of Helium Atoms by Electrons at Intermediate Energies
Authors: Seal S , Das JN
Published: November 2018

The triple differential cross section for electron impact ionisation of helium atoms has been calculated in the coplanar asymmetric geometry following the multiple scattering approach of Das. The method has already been successfully employed to describe the electron impact ionisation problem for the hydrogen atom. Here the impact energy of the incident electron is taken to be 150 and 250 eV in an intermediate energy range where there are still some discrepancies between theory and experiment. Present results are compared with the available experimental data and with two of the most recent calculations in some cases, and are found to be in reasonable accord with experiment, particularly in the binary peak region. The present calculation for 250 e V incident energy reproduces the experimental results in some cases better than other theories.
An Experiment to Test the Gravitational Aharonov-Bohm Effect
Authors: B Ho Vu , J Morgan Michael
Published: November 2018

The gravitational Aharonov-Bohm (AB) effect is examined in the weak-field approximation to general relativity. In analogy with the electromagnetic AB effect, we find that a gravitoelectromagnetic 4-vector potential gives rise to interference effects. A matter wave interferometry experiment, based on a modification of the gravity-induced quantum interference experiment of Colella, Overhauser and Werner (COW), is proposed to explicitly test the gravitoelectric version of the AB effect in a uniform gravitational field.
Positronium Formation Cross Sections for Scattering of Positrons from Potassium and Rubidium
Authors: Ranjit Singh N , Deb NC , Subodh Chandra Singh Th , Babuyaima Singh M , Mazumdar PS
Published: November 2018

Total cross sections for positronium formation in positron-potassium and positron-rubidium scattering have been calculated in a distorted wave approximation for incident positrons in the energy range 1 to 50 eV. The present results are compared with other theoretical results and with measurement where available.
Variations of Helicon Wave-induced Radial Plasma Transport in Different Experimental Conditions
Authors: Petržílka V
Published: November 2018

Variations of the helicon wave-induced radial plasma transport are presented depending on values of the plasma radius, magnetostatic field, plasma density and the frequency of the helicon wave. It is shown that the value of the helicon wave-induced transport may be significant for plasma confinement; this is demonstrated, for the experiments BASIL and SHEILA. Whereas m = +1 helicons induce an inward-directed transport and thus improve the confinement, m = -1 helicons induce an outward-directed transport velocity.
The Elastic Scattering of 20 eV Electrons from Magnesium
Authors: Brunger MJ , Houghton RK , Teubner PJO
Published: November 2018

A modulated crossed-beam technique has been used to measure the differential cross section for elastic scattering of electrons from the 31S state in magnesium at an impact electron energy of 20 eV. The cross section was measured over a range of scattering angles from 15� to 1300? Our results agree with the previous experimental cross sections of Williams and Trajmar within the combined uncertainties, however, the present data reduce the uncertainty by about an order of magnitude, thereby allowing a meaningful comparison to be made with the predictions of the various theories. At this time no theory accurately predicts the behaviour of the elastic differential cross section over the whole angular range. A complex phase-shift analysis is applied to the present data to derive the 20 e V integral elastic cross section. This integral cross section is also compared with the results of previous experiment and theory.
The Distribution of Electrons in a Uniform Electric Field
Authors: Stewart IM
Published: November 2018

Experiments are under way at the University of New England to measure the optical absorption of excited gas particles in a pre-breakdown discharge. Such measurements can be used to deduce the number density of electrons in the discharge. By comparing this experimental density map with the predictions of theory, electron transport parameters may be determined. In this paper, new theoretical expressions are derived for the number density distributions of electrons in a uniform electric field. These are found by solving the electron diffusion equation in a plane parallel electrode geometry with a radially symmetric cathodic current source. The contribution of ion-induced secondary current is included, and problems posed by non-equilibrium conditions near the electrodes are addressed. Techniques of data reduction are discussed with a particular emphasis on the avoidance of these problems.
Adaptive Deconvolution of Astronomical Radio Images
Authors: Cram Lawrence , Ye Taisheng
Published: November 2018

The novel image-forming methods used in the Molonglo Observatory Synthesis Telescope (MOST) are not amenable to a direct application of the self-calibration techniques that have been so effective in improving the performance of many other aperture synthesis radio telescopes. Specifically, self-calibration of antenna-based errors and the use of phase closure conditions is not possible because vital antenna-based information is lost irretrievably as the MOST forms interferometer beams in real time. However, it is shown in this paper that suitable models of errors introduced by the atmosphere and telescope can be adaptively constructed from the properties of synthesised images. These models can then be used iteratively with standard deconvolution methods to improve significantly the fidelity of MOST images. The method would have general application to tomographic imaging systems in which non-ideal behaviour could be represented by a small number of unknown parameters.
Time-dependent Density Functional Theory and Its Application to Liquid Dynamics
Authors: Munakata T
Published: November 2018

The density functional theory for classical (equilibrium) statistical mechanics is generalized so that one can discuss various dynamical processes associated with density fluctuations in liquids. This is effected by deriving a Langevin-diffusion equation for the density field, which satisfies a novel H-theorem. As applications of our theory we consider density fluctuations in both supercooled liquids and molecular liquids, interface dynamics and transport coefficients.