bluuebunny/crossref_metadata_2025 huggingface dataset:
Teaming up for biomarker future
Authors: Rinaldi Andrea
Published: June 2011

Biomarkers are an essential component of personalized, predictive medicine, but few have been used so far in the clinic. Industry, academic scientists and governments should make collaborative efforts to unleash their full potential.
Validating a Local Arterial Input Function Method for Improved Perfusion Quantification in Stroke
Authors: Willats Lisa , Christensen Soren , K Ma Henry , A Donnan Geoffrey , Connelly Alan , Calamante Fernando
Published: June 2011

In bolus-tracking perfusion magnetic resonance imaging (MRI), temporal dispersion of the contrast bolus due to stenosis or collateral supply presents a significant problem for accurate perfusion quantification in stroke. One means to reduce the associated perfusion errors is to deconvolve the bolus concentration time-course data with local Arterial Input Functions (AIFs) measured close to the capillary bed and downstream of the arterial abnormalities causing dispersion. Because the MRI voxel resolution precludes direct local AIF measurements, they must be extrapolated from the surrounding data. To date, there have been no published studies directly validating these local AIFs. We assess the effectiveness of local AIFs in reducing dispersion-induced perfusion error by measuring the residual dispersion remaining in the local AIF deconvolved perfusion maps. Two approaches to locating the local AIF voxels are assessed and compared with a global AIF deconvolution across 19 bolus-tracking data sets from patients with stroke. The local AIF methods reduced dispersion in the majority of data sets, suggesting more accurate perfusion quantification. Importantly, the validation inherently identifies potential areas for perfusion underestimation. This is valuable information for the identification of at-risk tissue and management of stroke patients.
Cerebral Glucose Utilisation in Hepatitis C Virus Infection-Associated Encephalopathy
Authors: Heeren Meike , Weissenborn Karin , Arvanitis Dimitrios , Bokemeyer Martin , Goldbecker Annemarie , Tountopoulou Argyro , Peschel Thomas , Grosskreutz Julian , Hecker Hartmut , Buchert Ralph , Berding Georg
Published: June 2011

Patients with hepatitis C virus (HCV) infection frequently show neuropsychiatric symptoms. This study aims to help clarify the neurochemical mechanisms behind these symptoms and to add further proof to the hypothesis that HCV may affect brain function. Therefore, 15 patients who reported increasing chronic fatigue, mood alterations, and/or cognitive decline since their HCV infection underwent neurologic and neuropsychological examination, magnetic resonance imaging, 18F-fluoro-deoxy-glucose positron emission tomography of the brain, and single photon emission tomography of striatal dopamine and midbrain serotonin transporter (SERT) availability. None of the patients had liver cirrhosis. Patients’ data were compared with data of age-matched controls. In addition, regression analysis was performed between cognitive deficits, and mood and fatigue scores as dependent variables, and cerebral glucose metabolism, dopamine, or SERT availability as predictors. Patients showed significant cognitive deficits, significantly decreased striatal dopamine and midbrain SERT availability, and significantly reduced glucose metabolism in the limbic association cortex, and in the frontal, parietal, and superior temporal cortices, all of which correlated with dopamine transporter availability and psychometric results. Thus, the study provides further evidence of central nervous system affection in HCV-afflicted patients with neuropsychiatric symptoms. Data indicate alteration of dopaminergic neurotransmission as a possible mechanism of cognitive decline.
A Computational Simulation of the Effect of Hemodilution on Oxygen Transport in Middle Cerebral Artery Vasospasm
Authors: Chittiboina Prashant , Guthikonda Bharat , Wollblad Christian , Conrad Steven A
Published: June 2011

Cerebral vasospasm after aneurysmal subarachnoid hemorrhage is a potentially severe sequel. The induction of hypertension, hypervolemia, and hemodilution is advocated for vasospasm, but it is unclear whether hemodilution confers any benefit. A finite element model of oxygen transport in the proximal middle cerebral artery (MCA) was used to evaluate the complex relationship among hematocrit, viscosity, oxygen content, and blood flow in the setting of vasospasm. A single-phase non-Newtonian finite element model based on three-dimensional incompressible Navier–Stokes equations was constructed of the M1 segment. The model was solved at vessel stenoses ranging from 0% to 90% and hematocrit from 0.2 to 0.6. A small area of poststenotic recirculation was seen with mild (30%) stenosis. Poststenotic eddy formation was noted with more severe (60% to 90%) stenosis. Volumetric flow was inversely related to hematocrit at mild stenosis (0% to 30%). With near-complete stenosis (90%), a paradoxical increase in flow was seen with increasing hematocrit. Oxygen transport across the segment was related to hematocrit at all levels of stenosis with increasing oxygen transport despite a reduction in blood flow, suggesting that with clinically significant vasospasm in the MCA, hemodilution does not improve oxygen transport, but to the contrary, that ischemia may be worsened.
Computerized Administration and Scoring of the Dichotic Nonsense Syllable Test
Authors: Lundeen Conrad
Published: June 2011

Purpose

A user-friendly computer program was designed to administer the dichotic nonsense syllable test (DNST). Computer automation makes it easier for listeners to perform the response task appropriately and for audiologists to administer and accurately score the test.

Method

The program presents test stimuli in a user-controlled, self-paced sequence; provides an easy-to-use client interface to collect listener responses; verifies that appropriate responses are recorded before proceeding with the test; scores responses automatically; and stores the information in an electronic format that is easy to analyze and archive.

Results

The automated DNST protocol is described. Verification tests confirm the accuracy of stimulus sequencing, response recording, and test scoring.

Conclusions

Computer automation makes administering the DNST easier, ensures the accuracy of test scoring, and simplifies the analysis and archiving of results. These refinements may make the DNST more useful to clinicians. Further research is required to establish normative data for this version of the DNST.
Services for Children With Central Auditory Processing Disorder in the Republic of Ireland: Current and Future Service Provision
Authors: Logue-Kennedy Maria , Lyons Rena , Carroll Clare , Byrne Mary , Dignan Eilis , O'Hagan Lucy
Published: June 2011

Purpose

An interdisciplinary research group was established to investigate current and future service provision for children with central auditory processing disorder ([C]APD) in the Republic of Ireland. The aim of Phase 1 was to identify current awareness and knowledge of (C)APD among the relevant professionals in Ireland, including level of service provision, if any, available for children with (C)APD. The aim of Phase 2 was to explore the initial steps required to develop an integrated service for children presenting with (C)APD.

Method

A quantitative design was used in Phase 1, and 520 surveys were distributed to speech and language therapists, audiologic scientists, and educational psychologists. A qualitative participative design was used in Phase 2.

Results

There was a 53% response rate to the survey. The main findings from Phase 1 were that all professional groups considered themselves to be inadequately informed and lacking in skills for (C)APD assessment or intervention. In Phase 2, 98 participants with backgrounds in speech and language therapy, audiologic science, educational psychology, and occupational therapy engaged in interdisciplinary discussions to identify the first steps required to develop a (C)APD service.

Conclusion

All professional groups considered that they were inadequately informed about (C)APD, and the first steps required to develop services in Ireland include the promotion and development of interdisciplinary teamwork and education, a need for additional resources, a clearer understanding of the definition of (C)APD, and evidence-based assessment and management of this condition.
Magnetotransport in a wide parabolic well superimposed with a superlattice
Authors: Pusep Yu.A. , Gusev G. M. , Bakarov A. K. , Toropov A. I. , Portal J. C.
Published: May 2011

The electron properties of artificially disordered superlattices embedded in a wide AlGaAs parabolic well were investigated in a strong magnetic field. We demonstrated that in the extreme quantum limit the interlayer disorder results in formation of a new correlated phase. A nearly uniform electron distribution over the superlattice wells was found in a weak magnetic field. However, a nonuniform phase with partially localized electrons, representing well-developed fractional quantum Hall effect features, was observed in high magnetic field (at the filling factor ν < 1). A distinct magnetic field–induced transition separates these two phases.
Simultaneous velocity-temperature measurements in the heated wake of a cylinder with implications for the modeling of turbulent passive scalars
Authors: Berajeklian A. , Mydlarski L.
Published: May 2011

Two principal quantities of interest in applications of scalar mixing in turbulent flows are the mean scalar and the scalar variance. Reynolds-averaged approaches are computationally efficient numerical methods that predict these fields. They require, however, the introduction of models to close the governing equations. Oftentimes, the numerical constants employed in these models include, or depend upon, the turbulent Prandtl number (PrT) and the mechanical-to-thermal time-scale ratio (r), which are generally assumed to be constant, but flow dependent. The present work studies the sensitivity of PrT and r to differences in their injection method within the same flow. To this end, mixed velocity-temperature statistics were measured in the wake of a circular cylinder. The wake was heated by one of two ways: heating the cylinder or heating an array of fine parallel wires (called a mandoline) placed downstream of the cylinder. The experimental results demonstrate that the magnitude of PrT varies throughout the wake for both scalar fields (and is consistently greater than the typical value of 0.7 generally used in turbulence models). Likewise, the values of r vary across the wake for both scalar fields and are lower than the generally accepted value of 2. The principal result of this paper, however, is that the measured values of both PrT and r differ for the two scalar injection methods, despite being within the same flow field. Hence, both PrT and r not only depend on the type of flow but also on the scalar field injection mechanism method as well—a result that is generally not taken into account when modeling the mixing of scalars within turbulent flows.
Modeling carrier transport and electric field evolution in Gaussian disordered organic field-effect transistors
Authors: Liu Fei , Lin Jack , Manaka Takaaki , Iwamoto Mitsumasa
Published: May 2011

Stimulated by the time resolved microscopic optical second-harmonic generation (TRM-SHG) experiment, we model the carriers transport and electric field evolution in the channel of three-dimensional Gaussian disordered organic field-effect transistors (OFETs) by the coupled time-dependent master equation and Poisson equation. We show that this model with the Miller-Abrahams rate can satisfactorily account for the experimental observations that include different profiles of the electric field in the channel and the diffusionlike migration of the field peaks with respect to time. Particularly, we find that the dynamic mobility proposed by us earlier is distinct from the standard one in the presence of a typical disorder, which is attributed to the uncompleted energy relaxation of the carriers in the transport process.
Radar Observations of Rain from Non-freezing Clouds
Authors: Styles RS , Campbell FW
Published: May 2011

It is now conceded that drizzle or light rain may fall from clouds which do not reach freezing level, but it is still not generally accepted that heavy precipitation is also possible from such clouds. This paper adds five further airborne radar observations of non-freezing rain (in the vicinity of Sydney, Australia; latitude 35 �S.) to the relatively few accounts of moderate to heavy precipitation already recorded as falling from such clouds.
Calculation of Accuracy of Results of Graphical Square Intercomparisons
Authors: Gilet PM , Watson GS
Published: May 2011

Graphical squares of two types are used for calculating the results of intercomparisons of standards of length, mass, and other quantities, and the results of calibration of scales. By means of graphical squares, estimates of the true values or " improved" values are obtained from observations. From the differences between the improved and observed values, the residuals, a measure of the accuracy of the intercomparison, may be obtained. In this paper expressions are derived which enable the calculation, from the residuals, of accuracies of observed values, of improved values, and of various quantities derived from the improved values.
Anomalous Absorption of Cosmic Rays in Lead
Authors: Kennedy WL
Published: May 2011

Anomalies in the lead absorption curve of the vertical component of cosmic radiation have been reported by several authors using counter telescopes (Aiya 1944; George and Appapillai 1945; Swann and Morris 1947; Kellermann and Westerman 1949; Fenyves and Haiman 1950; Mazzolli de Mathov. 1951; Abd EI-Wahab Khalil 1952). However, in a recent detailed series of experiments, results of which were published as the experiment to be described here was nearing completion, Heyland and Duncanson (1953) found no evidence of any anomaly in the absorption curve.
On a Theory Due to I. Fényes
Authors: Nicholson AF
Published: May 2011

F�nyes (1952) has attempted to base quantum mechanics on a theory of Markoff processes in the configuration space of any system considered.
Convection from a Large Horizontal Surface
Authors: Priestley CHB
Published: May 2011

A theory is put forward for convection from a large horizontal heated surface
in a semi�infinite medium, by buoyant elements which are subject to continuous mixing
with the environment by turbulence on a smaller scale. It is assumed, with support
from similarity arguments, that the (potential) temperature 6 at sufficient height z
above the surface obeys the form -(g/6)(iJ6/iJz)=Oz-a, where a and 0 are positive
constants. It is then shown: (i) that a must in practice be close to 4/3 and equal to it
under steady conditions, except in layers where radiational heating is large, where a
will be smaller; (ii) that the rate of heat 1088 varies as 0 312 ; and (iii) that the r.m.S.
temperature fluctuations are proportional to OZ-113. Experimental results from the.
surface layers of atmosphere support these predictions quite well.
The principal results are first suggested for free convection by dimensional and
similarity arguments. They receive independent confirmation from the mechanistic
theory, which extends into conditions when forced convection is present but not
dominant. The theory also provides information about the multiplying constants
in the above relationships, though it does not so far lead to a prediction of their exact
values. The multiplying constants depend, inter alia, on the mass ratio between the
ascending and descending air, and this remains constant through the layer of constant
heat flux. The behaviour of the ascending elements and that of the descending air are
shown to be quite differently governed.
The Measurement and Reduction of Distortion in Thick Emulsions
Authors: Hopper VD , Lim YK , C Walters Madeline
Published: May 2011

A study has been made of some of the factors influencing the distortion of developed images of tracks Ilford G5 400�. emulsions. It has been found that the effect of distortion on scattering measurements can be reduced to a negligible amount by developing the emulsions at 15 �C and drying with an alcohol-water solution of increasing concentration.
Delayed Disintegration of Heavy Fragments
Authors: A Brisbout Francoise , Hopper VD
Published: May 2011

Two examples of the delayed disintegration of heavy fragments somewhat similar to those observed by Danysz and Pniewski (1953), Tidman et al. (1953), and Crussard and Morellet (1953) ? have been found in this laboratory.
On the Coulomb and Hulthen Potentials
Authors: Ma ST
Published: May 2011

This paper contains the results of two investigations. (i) The Hulthen potential is considered as a modification of the Coulomb potential. The transition from the former to the latter is investigated. (ii) The zeros of the Fredholm determinant for the Hulthen potential are calculated from the first two terms of its power-series expansion. These approximate results are compared with the exact values.
Momentum Distribution and Charge Ratio of µ?Mesons at Zenith Angles in the East?West Plane
Authors: Moroney JR , Parry JK
Published: May 2011

The momentum distribution and charge ratio of the penetrating component of the cosmic radiation at sea-level have been determined over the 'momentum range- 0�24-58 BeVlc at a geomagnetic latitude of 47 oS. The measurements were performed in the vertical direction and at zenith angles of 30� and 60� in the eastern and western azimuths.
Fluctuations of Long?Period Accumulations of Daily Rainfall Amounts
Authors: Neumann J
Published: May 2011

In a recent communication, Bowen (1953) notes the tendency for heavy falls of rain at stations widely scattered over the southern hemisphere to occur on certain dates rather than on others. Surprisingly enough, records for the British Isles show maxima of frequency of heavy rain on the dates, or close to the dates, of peaks for the southern hemisphere stations concerned.
Scattering of 4·9 MeV Protons By 27Al
Authors: Mather KB
Published: May 2011

Since 1934 there have been 24 determinations of the level scheme of 2"7.Al. However, even the more recent findings are far from harmonious and the question naturally arises as to how much of the apparent discord is due to target contamination, inadequate resolution, etc., and how much follows from the use of different nuclear reactions where, presumably, selection rules may operate to control transition probabilities. For instance, four of the more recent reports claimed a doublet at .--1 MeV while the remainder found only a single level.
A Differential Refractometer of High Sensitivity
Authors: Guest PG
Published: May 2011

A graphical method is given for correcting the smoothing effect which arises when a celestial distribution of brightness temperature is scanned with an aerial beam. The method is much simpler to apply than previous methods which have been used and is no l
A Test for Singularities in Sydney Rainfall
Authors: Hannan EJ
Published: May 2011

An experimental investigation has been made of the minimum detectable echo power from meteor trails, using radar techniques at 69 Mc/s, with incoherent detection.
The Distribution of the Ratio of Two Quadratic Forms
Authors: Watson GS
Published: May 2011

The exact probability distribution of the ratio of two quadratic forms is given in the case where the quadratic forms and the multivariate normal distribution of the variables is such that the ratio is a ratio of linear functions of gamma variables of integral order.
On Starting Routines for the C.S.I.R.O. Mark I Computer
Authors: Hill GW , Pearcey T
Published: May 2011

High speed computers have a normal mode of operation whereby operations are specified by "commands" from stored programmes. This mode cannot be used for starting a cleared computer since there are no stored commands to perform the organized process of assembling commands from the input medium. Additional equipment is therefore required in order to provide another mode of operation for inserting the first, or primary, routine.
The Statistical Design of an Experiment to Test the Stimulation of Rain
Authors: Moran PAP
Published: May 2011

The problem of analysing statistically the results of a C.S.I.R.O. rainfall experiment over the catchment area of the Kiewa river is considered. It is shown that in order to obtain a significant result with any reasonable supposed increase in the rainfall within a few years it is necessary to use a control variable strongly correlated with the test variate. The powers of various tests using either streamflow or rainfall as test variates are calculated when the control variable is either streamflow in the Murray or rainfall in other areas. The general problem of designing such tests and the relationship between rainfall and streamflow are also considered.
Photodisintegration of 16O and 63Cu by Photons of Variable Energy
Authors: Campbell JG
Published: May 2011

Proton capture reactions in light nuclei provide ?-radiation with energy controllable by variation of proton energy. The radiation from proton capture by 7Li has been used to investigate the (?,n) reactions in 16O and 63Cu over an energy range of 300 keV around 17�7 MeV. No resonant behaviour was observed in 16O. A variation in the 63Cu photoneutron cross section is interpreted as the combined effect of many unresolved levels.
Photoprotons from Fluorine
Authors: Lasich WB , Muirhead EG , Shute GG
Published: May 2011

The energy and angular distributions of protons produced in the 19F (?, p) reaction have been obtained for the photon energy range 10?16�5 MeV. An integrated cross section of 18 MeV-mbarn was obtained for this region. The angular distribution was found to be of the form (a+b sin2?) with the ratio b/a strongly energy dependent. The higher energy protons show evidence of an independent particle-type interaction which is in plausible agreement with the shell model structure of fluorine.
Movement of Sporadic E Ionization
Authors: Harvey JA
Published: May 2011

The, horizontal movement of patches of day-time sporadic E ionization has been observed by using a system of spaced pulse transmitters and a central recorder. The directions of movement are mainly towards the north and west, with speeds mainly between 40 and 80 m/sec. These velocities differ in direction from the F region disturbances recorded at the same time and have only about half the speed.
Thermal and Electrical Conductivities of Iron, Nickel, Titanium, and Zirconium at Low Temperatures
Authors: Kemp WRG , Klemens PG , White GK
Published: May 2011

Measurements are reported of the thermal and electrical conductivities of iron, nickel, titanium, and zirconium down to 2 �K. These indicate that thermal conduction in pure iron and nickel is almost completely electronic. Titanium and zirconium exhibit an appreciable lattice component of thermal conduction. In the case of titanium this lattice component varies as T1.5.
Cusp Type Anomalies in Variable Frequency Ionospheric Records
Authors: Munro GH , Heisler LH
Published: May 2011

Anomalous cusps which frequently appear at the high frequency end of ionosonde records of the F2. region are explained as the result of modification of the ion distribution during the passage of typical travelling disturbances. They indicate the presence, not of vertical stratification but of horizontal gradients of ionization causing oblique reflection. It is suggested that other anomalous cusps are of similar origin.
Divergence of Radio Rays in the Ionosphere
Authors: Munro GH , Heisler LH
Published: May 2011

Travelling disturbance manifestations on ionosonde records usually occur at different times on the "o" and "x" traces. It is shown that this is due to the divergence of the ordinary and the extraordinary rays in the Earth's magnetic meridian plane and that the sense of this time difference, therefore, gives a direct indication of the sense of the north-south component of movement of the disturbance. Furthermore, where the direction and speed of travel of a disturbance can also be determined from spaced station observations, the actual separation of reflection points of the o- and the x-rays can be deduced. At Sydney, N.S.W. (33� 52' S., 151� 11' E.) this is of the order of 30 km at the height of maximum ionization of the F2 region. On h't records the corresponding time difference observed includes a component due to the vertical separation of reflection points if the front of the disturbance is not vertical. From records of this type taken at three spaced stations the horizontal component may be determined directly. Examination of some 430 such observations taken over a period of 4 years confirms the variation of the time difference with direction of travel predicted by theory, and also indicates the consistent presence of a forward tilt in the front of disturbances.
Bounds for the Collapse Load of a Beam Compressed by Three Dies
Authors: Freiberger W
Published: May 2011

This paper deals with the problem of the plastic deformation of a beam under the action of three perfectly rough rigid dies, two dies applied to one side, one die to the other side of the beam, the single die being situated between the two others. It is treated as a problem of plane plastic flow. Discontinuous stress and velocity fields are assumed and upper and lower bounds for the pressure sufficient to cause pronounced plastic yielding determined by limit analysis.
Counts of Atmospheric Freezing Nuclei at Carnarvon, Western Australia, January 1956
Authors: Bigg EK
Published: May 2011

A new instrument for measuring freezing nucleus concentration is described, and an account given of a series of measurements made at Carnarvon in Western Australia during January 1956. The measurements were made on the ground in marine air with a long travel over the Indian Ocean and are thought to be free from contamination by terrestrial dust and smoke from industrial sources.
An Application of the Diffusion Equation to Viscous Motion with a Free Surface
Authors: Philip JR
Published: May 2011

The recent development of methods for the numerical solution of the diffusion equation when the diffusivity is concentration-dependent enables' certain phenomena, previously not amenable to quantitative analysis or ineffectively described by empirical functions, to be studied more fully. This communication points out an example of concentration-dependent diffusion which does not appear to have previously received attention.
Numerical Solution of Equations of the Diffusion Type with Diffusivity Concentration?Dependent. II.
Authors: Philip JR
Published: May 2011

A new procedure is developed for the numerical solution of the equation with D and K single-valued functions of ? and the conditions ? = ?n, t=0, x>0; ?=?0 , x = 0, t:> 0. Difficulties inherent in the one method previously suggested are avoided, the problem being reduced to one of solving a set of ordinary differential equations.
Transient Fluid Motions in Saturated Porous Media
Authors: Philip JR
Published: May 2011

The transition from rest to steady motion on the sudden application of a potential gradient to the fluid contained in a saturated porous medium is investigated. An approximate analysis gives the result that the time of the effective establishment of the steady motion is proportional to the permeability and inversely proportional to the kinematic viscosity. Two exact solutions (one of them new) for simple cases suggest that the approximate analysis is remarkably accurate. An analogy between this problem and one in heat conduction makes the relevant results in that field immediately applicable here.
The Distribution of the Orbits of Sporadic Meteors
Authors: Weiss AA
Published: May 2011

The directions of the reflection points of sporadic meteor trails for March and September 1953, and the hourly echo rates of sporadic meteors obtained from the Adelaide radio survey of meteor activity over 1952?1956 are analysed. Diurnal and annual variations in the sporadic echo rate are predicted from contemporary theory on the reflection of radio waves from meteor trails for several model distributions. A sporadic distribution is derived which consists of a concentration of direct short-period orbits to the plane of the ecliptic superimposed upon a more uniform distribution of near-parabolic orbits. This distribution is consistent with the results of radar, visual, and telescopic surveys in the northern hemisphere. The density of sporadic meteors round the Earth's orbit is also derived.
Programme Design for the C.S.I.R.O. Mark I Computer. IV. Automatic Programming by Simple Compiler Techniques
Authors: Hill GW , Pearcey T
Published: May 2011

Techniques are described for using the C.S.I.R.O: Mark I computer to assemble complete programmes from greatly reduced input programmes by selecting and transferring routines from standard libraries and forming appropriate commands to interconnect routines and the problem programme. The "compiler" process is described for computer-code programmes and for hyper-code programmes which use interpretive routines to provide elaborate arithmetical operations corresponding to each hyper-code.
Solution of Flow Problems in Unidimensional Lagrangian Hydromagnetics
Authors: Loughhead RE
Published: May 2011

A problem of considerable interest in many branches of astrophysics is that of the subsequent behaviour of a current which at an initial time t = 0 is largely concentrated within a given region of an ionized gas of infinite extent. In particular, it has been suggested by Alfv�n (1950) that a high current discharge in an ionized gas is likely to constrict because of the electromagnetic attraction' between parallel currents and that this constriction effect may be involved in the formation of solar prominences. Similar considerations may also be of importance in studies of magnetic fields in the spiral arms of the Galaxy.
Some Observations on the Behaviour of Bromine?Quenched Geiger Tubes
Authors: Belin RE
Published: May 2011

A number of Geiger tubes were constructed using 18:8 low-carbon stainless steel and 99� 9 + per cent. aluminium cathodes with tungsten anodes.
A Study of the Audio?Frequency Radio Phenomenon Known as "Dawn Chorus"
Authors: McK Allcock G
Published: May 2011

The main characteristics of dawn chorus, as observed at Wellington, New Zealand, between July 1955 and October 1956, are presented. These are: no general correlation with whistlers; a strong correlation with simultaneous local magnetic variations; a pronounced diurnal variation in activity, with the peak occurring near 0400 hr local time; and possibly a weak seasonal variation in activity.
A New Absolute Method of Hygrometry. I. The General Principles of the Method
Authors: Wylie RG
Published: May 2011

This paper is the first of two which give a detailed treatment of a new method of hygrometry. In this method an ionic single crystal is surrounded by the gas which is the subject of measurement, and the temperature of the whole is so adjusted that a very thin layer of saturated solution is formed on the crystal surface and is brought to a constant thickness as determined electrically. The temperature thus established provides a measure of the absolute humidity of the gas.
Meteor Radiant Determination from High Echo?Rate Observations
Authors: Keay CSL
Published: May 2011

A simplified analysis is given of the Clegg method for delineating meteor radiants from radar observations. A further analysis reveals a new and faster method of interpreting the data contained in meteor echo records. This method is applicable when sensitive equipment is employed and the resulting echo rate is very high.
Dispersal of Dust Particles from Elevated Sources. II. Limitations of the Approximate Theory
Authors: Csanady GT
Published: May 2011

This paper forms a continuation of a previous one (Csanady 1955) wherein Sutton's continuous point source equations were extended to the case of heavy particles of uniform free falling speed. The solution obtained there was an approximate one; limits of validity are discussed in detail in the present paper. This discussion is preceded by a generalization of the earlier solution and two charts are presented to aid calculation of the "mirror image multiplier", the basic function of the� approximate theory.
The Design of Photographic Objectives of the Triplet Family. I. The Design of the Triplet Type 111 Objective
Authors: Cruickshank FD
Published: May 2011

A general study has been made of the initial design of photographic objectives of the triplet family of objectives. A classification is suggested. The point of view is taken that it is convenient to regard the first two members of a triplet as constituting a compound corrector system to the rear positive member.
Further Observations of Radio Emission from the Planet Jupiter
Authors: Gardner FF , Shain CA
Published: May 2011

The results of further observation of Jupiter radiation, made near Sydney from June 1955 to March 1956, are presented. Most work was done at 19�6 Mc/s, but some observations were also made at 14 and 27 Mc/s.
Decay Time of the Luminescence of a Zinc Sulphide Neutron Detector for Neutron and g-Ray Excitation
Authors: Bailey GM , Prescott JR
Published: May 2011

In experiments being conducted in this laboratory on (d,n?) reactions rising fast coincidence techniques, an attempt was made to use phosphors containing zinc sulphide as the neutron detector.
The Lifetime of Sunspot Penumbra Filaments
Authors: Bray RJ , Loughhead RE
Published: May 2011

Twenty-seven photographs of a sunspot showing a particularly distinct filamentary structure are analysed in order to obtain an estimate of the lifetime of the penumbral filaments. The photographs have been selected from some 2400 taken over a period of 5 hr. Although the measurements are rendered somewhat uncertain by observational difficulties the results clearly indicate that some filaments remain identifiable for periods of the order of hours.
Lunar Tides in E2s at Brisbane
Authors: Gazzard AD
Published: May 2011

From an analysis of the Brisbane h'Es data for 1953, Thomas and Svensons? have deduced the existence of a lunar semi-diurnal tide, with amplitude 0 �69 km, and epoch of maximum at 6� 7hr local time. The present author has made a. similar analysis of the Brisbane h'E2s data for the two years, 1952-1953, using nearly 3000 hourly readings.
On the Radio Emission of Hydrogen Nebulae
Authors: Wade CM
Published: May 2011

The interpretation of radio-frequency observations of H II regions is discussed with particular regard for the possible effects of random variations in the electron density and electron temperature through the nebulae. It is shown that such variations serve to alter the optical depth and that the conventional definition of the "emission measure" requires modification if it is to be considered an observable quantity. The radio emission of Str�mgren spheres is discussed, and a means of determining their electron temperatures is described. An empirical method for the determination of Str�mgren's constant defining the ionized volume as a function of the spectral type and luminosity of the exciting star is described.
The Constancy of the Velocity of Light
Authors: Builder G
Published: May 2011

The principle of the constancy of the velocity of light has generally been given a prominent place in discussions of the restricted theory of relativity. Yet lack of any clear and unambiguous statement of the principle has led to its frequently being misunderstood and to its sometimes being adduced as a basis for fallacious conclusions.
A Search for Radio Emission at 3·5 m from the Local Supergalaxy
Authors: Hill ER
Published: May 2011

As described by de Vaucouleurs (1953, 1956) the local supergalaxy is a large flattened system of galaxies and clusters of galaxies centred near the Virgo cluster. It is seen most clearly in the northern galactic hemisphere as a band of bright galaxies about 10� wide extending along a great circle. Our Galaxy appears to be near the rim of this system.
Approximations for the Electron Density in Meteor Trails
Authors: Weiss AA
Published: May 2011

Herlofsen (1947) has shown that an exact solution of the equations governing the evaporation of a meteor particle during its flight in the upper atmosphere can be obtained in the special case of a spherical meteor in an isothermal atmosphere. In terms of the number n of meteor atoms evaporated in unit length of trail, the electron density a is . (1)
Observations of Faculae Bordering Small Sunspots Near the Limb
Authors: Loughhead RE , Bray RJ
Published: May 2011

It has long been known that there is a close association between sunspots and white-light faculae. No spots near the limb are observed without attendant faculae and, conversely, except for the polar faculae, which occur in zones where spots do not normally appear, there are few faculae which are not associated with spot groups at some stage of their lives.
Radiative Transfer in Non-uniform Media
Authors: Giovanelli RG
Published: May 2011

The equation of radiative transfer incorporating Eddington's approximation is expressed in a form applicable to an inhomogeneous medium, as
Seismic Recordings of Large Explosions in South-Eastern Australia
Authors: Doyle HA , Everingham IB , Hogan TK
Published: May 2011

Three very large quarry explosions of between 50 and 100 tons of high explosive in the Snowy Mountains area were recorded by seismographs at distances up to 375 km. P and S wave velocities within the Earth's crust for this part of south-eastern Australia were formally determined to be 6�04 (�0'04) and 3�62 (�0�03) km/sec, respectively. The P n velocity was found to be 8� 03 km/sec, with an estimated error of O� 2 km/sec. Assuming a uniform layer above the Mohorovicic discontinuity with these velocities, the discontinuity was formally estimated to be at a depth of 37 km.
The Thermal Expansion of Solids
Authors: Fletcher GC
Published: May 2011

From the theory of normal vibrations of a lattice, a practical means of obtaining the equation of state of an ionic solid is developed from which the thermal expansion can be derived. Using previous work by Kellermann, application is made to the case of sodium chloride and the results compared with experiment. Possible reasons for the discrepancy between theory and experiment, which is very large at 'high temperatures, are discussed. The variation with temperature of the specific heat at constant volume and the isothermal compressibility are also investigated.
Scattering of High Energy Polarized Nucleons by Complex Nuclei
Authors: Robson BA
Published: May 2011

The elastic scattering of 220 MeV polarized nucleons by carbon and calcium is studied using a new expression for the polarization. Except at small angles of scattering, substantial agreement is obtained with the results of calculations using a simplified form of the WKB method. Optical model parameters are found which are compared with those obtained by other workers for this energy region.
Note on Band Transmission in Multilayer Dielectric Filters
Authors: Gascoigne SCB
Published: May 2011

The existence of pass and stop bands for periodically stratified media, in particular for multilayer dielectric filters, is well known, but there seems to be no way of demonstrating this either without the use of a good deal of algebra or by appeal to relatively unfamiliar ideas, such as those of transmission line theory. Our purpose here is to show that for an infinite medium, this result can be established by a direct adaptation of the Kronig-Penney (1931) model for metal lattices. Accounts of this model are given in a number of textbooks (Rojansky 1942; Brillouin 1946) and also in undergraduate courses in this country, so that it may be considered well known. Mathematical details will accordingly be abbreviated; they may be found in the references cited.
A New Method for Measuring the Attachment of Slow Electrons in Gases
Authors: Huxley LGH , Crompton RW , Bagot CH
Published: May 2011

Recent determinations of attachment and ionization coefficients have been carried out using a number of different techniques including (i) a method due in the first instance to Lozier using an electron beam (Craggs, Thorburn, and Tozer 1957; Tozer, Thorburn, and Craggs 1958), (ii) a development of Townsend's Driginal method of determining ionization coefficients by the measurement of ionization currents between parallel plane electrodes of variable separation (Geballe and Harrison 1952, 1953), and (iii) a modification of Doehring's method depending on measurements of time of flight (Chanin, Phelps, and Biondi 1959). In experiments of the second and third type it is not possible to estimate experimentally the mean energy of the electrons and, if the coefficients are to be expressed as functions of electron energy, it is necessary to use the results of independent experiments.
High Resolution Observations of the Granular Structure of Sunspot Umbrae
Authors: Bray RJ , Loughhead RE
Published: May 2011

High resolution photographs of sunspot umbrae have confirmed the existence of an umbral granulation, resembling the photospheric granulation but differing in regard to lifetime and cell size. Bright structures in the form of " loops" are also seen. Quite apart from the granulation, the intensity contours of spot umbrae show a detailed and complex structure.
An Association Between Solar Radio Bursts at Metre and Centimetre Wavelengths
Authors: Neylan AA
Published: May 2011

From a study of simultaneous metre and centimetre solar radio bursts, it appears that the type III events which coincide with centimetre bursts are frequently followed by a particular form of broad� band emission. This last burst, termed type V, is observed mainly below 150 Mc/s on radio spectrum records where it resembles a bright glow lasting for about 1 min. Synchrotron radiation has been suggested as the mechanism for type V bursts.
The Lattice Thermal Conductivity of Some Gold Alloys
Authors: Birch JA , Kemp WRG , Klemens PG , Tainsh RJ
Published: May 2011

The electrical and thermal conductivities of the following gold alloys have been measured from 2 to 90 oK: Au-0�7 per cent. Pt, Au-l�6 per cent. Pt, Au-l�g per cent. Pt, Au-0�65 per cent. Cr, and Au-6'2per cent. Cr. Their lattice thermal conductivities have been deduced and the effects of annealing studied. It is found that in well-annealed dilute alloys, the lattice conductivity at liquid helium temperatures approaches a value consistent with theoretical predictions. It appears that increasing solute content causes an increasing dislocation density, which cannot be reduced substantially by annealing. This effect is more pronounced in the case of the chromium alloys. The lattice thermal conductivities at liquid oxygen temperatures compared with theory reveal numerical discrepancies, similar to those found in copper alloys.
A Relation Between Ionospheric Drifts and Atmospheric Dynamo Current Systems
Authors: Heisler LH
Published: May 2011

Travelling ionospheric disturbances have been studied at this laboratory over a considerable period using fixed frequency observations on 5�8 Mc/s. They are observed as anomalies in height on ionospheric records at three stations, spaced approximately 40 km apart. Munro (1950) has used normal triangulation techniques to determine speeds and directions and has shown (Munro 1958) that their average speed is 7 km/min with median directions 30� east of north during the winter and 120� east of north by day, during the summer months. In both seasons there is a marked easterly component. However, in recent sunspot maximum years during summer, a predominant westerly component is evident on certain days.
Free Path Formulae for the Coefficient of Diffusion D and Velocity of Drift W of Ions and Electrons in Gases
Authors: Huxley LGH
Published: May 2011

In derivations of formulae for D and W for electrons by the method of free paths (Huxley 1957a, 1957b) the assumption was made that along a number of successive free paths an electron travels at essentially the same speed c. As this assumption is not true of ions it would not be legitimate to apply the formulae to the motion of ions in gases without further discussion. However, the formulae are in fact valid for ionic motion and in what follows they are established in a more general form.
Study of the Flare?Surge Event of September 7, 1958
Authors: M Lowman Karen , Billings DE
Published: May 2011

Giovanelli and McCabe (1958) indicate that, while most flare-surges appear dark against the solar disk throughout the greater part of their existence, it is not uncommon for a surge in its earliest stages, just as it leaves the flare, to be bright. Rapidly moving material that remains bright against the solar disk for a longer time is much less frequently observed. Of the cases of longer lasting bright surges that have been reported as exceptional events by Dodson and Hedeman (1949, 1952), Ellison (1950), Dodson and McMath (1952), Bray, Loughhead, Burgess, and McCabe (1957), and Reid (1959), those reported by Dodson and McMath, by Bray et al., and by Reid appear to be detached and rapidly moving portions of flares, whereas the remainder did not attain flare brightness.
Distribution of Auroras in the Southern Hemisphere
Authors: Bond FR , Jacka F
Published: May 2011

Several attempts to delineate the southern zone of maximum frequency of visibility of auroras have led to widely discrepant results. That of White and Geddes (1939) suffered through lack of observations; that of Vestine and Snyder (1945) was based on observed relations between morphology of geomagnetic disturbance and auroras in the northern hemisphere, and application to the southern hemisphere using very limited geomagnetic data. It may be, too, that the distribution of auroras changes slowly with solar activity.
Focusing of Radio Waves Reflected from a Rough Curved Ionosphere
Authors: Whitehead JD
Published: May 2011

The reflection of radio waves from a partially rough, curved ionosphere is considered. The relationship between the amplitude of the echo, A, and phase path P when the ionosphere moves overhead with a horizontal velocity V at a height h is the same as that for a smooth curved ionosphere, i.e.
A Study of Whistling Atmospherics. I. Occurrence
Authors: Crouchley J
Published: May 2011

The occurrence of whistling atmospherics at four Australian stations (Brisbane, Adelaide, Hobart, and Macquarie Island) over the LG.Y. period is discussed. A strong seasonal variation is observed at each station, with the maximum occurrenceduring local winter, and also a strong diurnal variation with a minimum during daylight hours. Whistlers are observed more commonly at about geomagnetic latitude 45�. Autocorrelation analysis suggests recurrence tendencies in the occurrence figures and cross�correlation with sunspot numbers and Adelaide data indicates an association between the two. There is little evidence of association between whistler occurrence .and magnetic planetary index.
Excited States of 64Zn
Authors: Kenny MJ , Caro DE
Published: May 2011

The reaction 63Cu(p,n)63Zn has been studied at bombarding energies between 5 and 11 . 5 Me Y using an activation technique with good energy resolution. Previously unknown levels in 64Zn at excitation energies of approximately 13'37,'13'75, 14'12, 14'3" 14�90' 15�1., 15'6" and 15�77 MeY have been found. It is shown that six of these levels, and the observed absence of levels in some energy regions, can be accounted for in terms of Nilsson's calculations for the single-particle states of a deformed nucleus. If this interpretation is correct, the deformation of 64Zn must be negative, at least in its highly excited states.
Inelastic Scattering of Protons on 12C
Authors: McKenna VR , Shute GG
Published: May 2011

During the recent Variable Energy Cyclotron experiment involving the elastic scattering of protons on 12C, the complete energy spectrum of the scattered protons was obtained by means of a 100-channel analyser (McKenna, Baxter, and Shute 1961, henceforth referred to as I). Two prominent peaks were obtained: the higher energy one corresponding to elastic scattering and the lower energy one to inelastic scattering with the residual carbon nucleus being left in its first excited state, 4� 43 MeV. In I the elastic scattering results were reported briefly. The purpose of this short communication is to discuss the main features of the inelastic scattering.