bluuebunny/crossref_metadata_2025 huggingface dataset:
Noise-Induced Hearing Injury and Comorbidities Among Postdeployment U.S. Army Soldiers: April 2003–June 2009
Authors: Helfer Thomas M. , Jordan Nikki N. , Lee Robyn B. , Pietrusiak Paul , Cave Kara , Schairer Kim
Published: June 2011

Purpose

To evaluate noise-induced hearing injury (NIHI) and blast-related comorbidities among U.S. Army soldiers in an effort to understand the morbidity burden and future health service requirements for wounded war fighters returning from the Central Command Area of Responsibility, predominantly from Iraq and Afghanistan deployments.

Method

Inpatient and outpatient records with diagnosed NIHI or blast-related comorbidities (e.g., significant threshold shift [STS], noise-induced hearing loss, tinnitus, sensorineural hearing loss, eardrum perforations, mild traumatic brain injury, and posttraumatic stress disorder) were extracted for active duty soldiers returning from combat deployments. Records were limited to those within 6 months of the soldier’s return date from April 2003 through June 2009. To account for changes in STS coding practice, STS rates observed after October 1, 2006, were used to extrapolate prior probable postdeployment STS.

Results

Statistically significant increases were observed for tinnitus, dizziness, eardrum perforations, and speech-language disorders. The combination of observed and extrapolated STS yielded a conservative estimate of 27,427 cases.

Conclusions

Estimates can be used to forecast resource requirements for hearing services among veterans. This article could serve as a guide for resourcing and innovating prevention measures and treatment in this population. Data provided may also serve as a baseline for evaluating prevention measures.
The effect of improved aluminium tolerance on establishment of the perennial grass, phalaris, on strongly acid soils in the field and its relation to seasonal rainfall
Authors: Culvenor R. A. , McDonald S. E. , Veness P. E. , Watson D. , Dempsey W.
Published: June 2011

We examined the hypothesis that the higher aluminium (Al) tolerance of recent cultivars of the perennial grass, phalaris (Phalaris aquatica L.), improved establishment on strongly acid soils and that expression of this tolerance depended on seasonal rainfall conditions. Establishment under a range of conditions by a new cultivar (Advanced AT) with the highest Al tolerance yet achieved was compared with another relatively tolerant cultivar (Landmaster) and less tolerant cultivars and some alternative species on strongly acidic soils by sowing twice per year at six sites over 3 years (2004–06). Seedlings were considered established if they survived the first summer as shown by frequency and yield in the year after sowing.
Low autumn rainfall in all years hindered weed control and delayed sowing. Under adequate rainfall in 2004 and 2005 sowings, Advanced AT and Landmaster established similarly and were denser and more productive, on average, than Holdfast and Sirosa, which in turn were higher than Australian II, an order related to Al tolerance measured in solution. Persistence in later years was ranked similarly. Under very adverse spring drought conditions in 2006, Advanced AT established better than Landmaster at the most acidic sites as hypothesised. Soil pH of sites where Advanced AT established better than Landmaster in 2006–07 was <4.2 in CaCl2. The results suggested that current recommendations on the tolerance of phalaris to acid soils are too conservative and that phalaris is more suitable for acid soils in southern Australia than these recommendations indicate.
Use of normalised difference vegetation index, nitrogen concentration, and total nitrogen content of whole maize plant and plant fractions to estimate yield and nutritive value of hybrid forage maize
Authors: Islam M. R. , (Yani) Garcia S. C. , Henry D.
Published: June 2011

This study was conducted to investigate the potentials of normalised difference vegetation index (NDVI), nitrogen (N) concentration (%), and N content (g/plant) of whole maize plant to estimate yield and nutritive value of hybrid forage maize. Hybrid forage maize was grown with two rates of pre-sowing fertiliser N (0, 135 kg/ha) and three rates of post-sowing fertiliser N (0, 79, 158 kg N/ha) applied at the six-leaf stage. Data on the NDVI and N (% and g/plant) of maize were collected at 2-, 3-, 6-, 8-, 12-, 16-, 18-leaf stages and at harvest. Metabolisable energy (ME) content of the whole maize plant at harvest was estimated from in vitro digestibility. Simple, polynomial, and multiple regression analyses were conducted and only the best-fit models were selected. The 8-leaf stage was found to be the most effective stage for use of the NDVI in predicting biomass yield (R2 = 0.81), grain yield (R2 = 0.72), and N (%) (R2 = 0.92) of forage maize. Nitrogen (%) at the 8-leaf stage was also best related to biomass yield (R2 = 0.88). Multiple regressions at the 3-leaf stage increased the coefficient of determination for both biomass yield and grain yield (R2 = 0.77) over the relationships obtained from N (%) of the whole plant at 2- or 3-leaf stage. The NDVI and N (%) of the whole plant at 8-leaf stage were the best predictors of yield, but failed to predict ME content of the hybrid forage maize. Multiple regression models at the 3-leaf stage were almost as effective as the NDVI and N (%) of whole maize plant at the 8-leaf stage in predicting biomass and grain yield of forage maize.
Growth and yield responses to amendments to the sugarcane monoculture: effects of crop, pasture and bare fallow breaks and soil fumigation on plant and ratoon crops
Authors: Garside A. L. , Bell M. J.
Published: June 2011

Yield decline has been a major issue limiting productivity improvement in the Australian sugar industry since the early 1970s and is suspected to be largely due to growing sugarcane in a long-term monoculture. In order to address this issue, rotation experiments were established in several sugarcane-growing regions in Queensland, Australia, to ascertain whether breaking the sugarcane monoculture could, at least in part, assist in overcoming yield decline. The rotation experiments involved other crop species, pasture and bare fallow for different periods of time. When cane was replanted, the growth and yield following breaks was compared with that in a sugarcane monoculture system where the soil was unamended or fumigated before replanting. Yield increases were recorded in the plant and first ratoon (R1) crops in all experiments: in response to soil fumigation (average of 42 and 18%, respectively), and breaks (average of 27 and 30%, respectively). The data indicated that the response to breaks, while smaller in the plant crop, may have greater longevity than the response to fumigation. Further, there were indications that the response to breaks could continue into later ratoons (R2 and R3). Break type had little overall effect with the average response in the plant and R1 crops being 35% for breaks in excess of 30 months. Breaks of longer duration produced larger yield responses: 17% (<12 months), 24% (18–30 months) and 28% (>30 months) in the plant crop. However, the average yield increase over a plant and three ratoon crops when one cane crop was missed (6–12 months’ break) and a grain legume or maize break included was ~20%. Yield increases with breaks and fumigation were due to either increased stalk number, increased individual stalk weight or a combination of both. The component accounting for the majority of the variance changed between experiments, with a general trend for individual stalk weight to have more impact under better late season growing conditions and/or conditions that hampered early stalk development, while stalk number was more important under conditions of late season water stress and/or low radiation input. The results demonstrate that the long-term sugarcane monoculture is having an adverse effect on productivity. Further, breaking the sugarcane monoculture and sacrificing one sugarcane crop is likely to have minimal impact on the supply of cane to the mill. The increase in yield during other stages of the cane cycle is likely to compensate for the loss of 1 year of sugarcane, especially as the crop that is sacrificed is the last and almost always lowest-yielding ratoon.
Solution of the Inverse Reaction Problem for Complex Potentials
Authors: Bertram WK , Cook JL
Published: June 2011

A method is given for solving the inverse reaction problem to obtain complex potentials as in the optical model of the nucleus. The method reproduces reaction data to the accuracy with which the reaction matrix can be least squares fitted to a sum of simple poles. The method couples multichannel phase shifts in such a way as to give the correct complex single-channel phase shift.
Gamma Ray Decay Schemes of Levels at Intermediate Energies in 32S
Authors: Moss CE , Spear RH , Ahmad F , Baxter AM , Carlson LE , Gardner PR
Published: June 2011

The reaction 32S(p,p'y)32S has been studied with a 12'7 cm by 10�2 cm NaI(TI) y-ray detector in conjunction with a 61 cm double-focusing magnetic spectrometer to determine the y-ray decay schemes of all known levels in 32S between the excitation energies of 5�40 and 7� 15 MeV.
Analysis of (d, p?) Reactions
Authors: Steketee CF , McKellar BHJ
Published: June 2011

The reactions 24Mg(d, py)25Mg via the 3 �40 MeV state, 4�Ca(d,py)41Ca via the 1�95 MeV state, and 28Si(d,py)29Si via the 2�03 MeV state are analysed using the stripping theory developed by Butler, Hewitt, McKellar, and May. The theory is in reasonable agreement with the experimental data. It is pointed out that a study of the correlation as a function of the proton scattering angle is necessary to obtain a test of this theory vis-it-vis the standard DWBA theory of stripping reactions.
Detection of Interstellar Thioformaldehyde
Authors: Sinclair MW , Fourikis N , Ribes JC , Robinson BJ , Brown RD , Godfrey PD
Published: June 2011

The 211 +-212 transition of thioformaldehyde (HCHS) has been observed in absorption in the direction of SagittariusB2. For a rest frequency of 3139� 38 MHz the peak absorption occurs at a radial velocity of 60 � 4 km s -1. The half-width of the absorption profile is equivalent to 20 kms-1 and the column density of HCHS is greater than 1016 molecules cm - 2. Comparison with the 211 +-212 absorption of formaldehyde (HCHO) at 15 GHz allows the relative abundance of the two molecular species to be computed as a function of the rotational excitation temperature. For thermal equilibrium the strength of the 110-111 absorption in SgrB2 by thioformaldehyde predicted from the 211+-212 HCHS observations is considerably greater than the limits set by a number of observers for the 110-111 transition at 1046 MHz.
Infrared Active Two?Phonon Processes in Cubic ZnS
Authors: Srivastava SP
Published: June 2011

Results are presented of a study of the infrared transmission spectrum of cubic ZnS at room temperature. Besides the fundamental lattice absorption, a number of subsidiary bands due to the interaction of infrared radiation with more than one lattice phonon in the frequency range 250-800 cm - 1 have been observed. These multiphonon bands are explained using inelastic neutron scattering data for the four characteristic phonon frequencies at various critical points and applying selection rules.
Australian Journal of Physics Astrophysical Supplement
Authors: Slee OB , Higgins CS
Published: June 2011

The Culgoora radioheliograph operating at 80 MHz has been used to observe 999 radio sources selected from published catalogues and distributed over the declination range -48� to +35�. The Culgoora-l list contains measurements with 3' . 7 arc resolution of positions, flux densities, and angular sizes of 777 sources, while upper limits to the flux densities of 222 undetected sources are given in a separate list. Success rates for the detection of various classes of radio source at 80 MHz are listed and discussed. Comparisons are made between the Culgoora flux densities and those given in other catalogues, and it is shown that unresolved sources in the earlier low-resolution measurements near 80 MHz cause the flux density to be systematically overestimated.
Self-Consistent Transformation of Bremsstrahlung to Monochromatic Photoneutron Mean Energies of Non-Maxwellian Neutron Spectra
Authors: Koch R , Crawwford DM , Bottcher K , Thies HH
Published: June 2011

The mean energy of neutrons produced in a bremsstrahlung experiment can be measured using "energy sweeping" and a multi-BF3-counter neutron detection system. It is shown here how one can obtain from a relatively simple type of experiment the required calibration data of the detection system to permit a self-consistent transformation of the bremsstrahlung data to the equivalent monochromatic photon data for neutron spectra that are non-Maxwellian.
On the Theory of the Diffusing Electron Stream in a Gas
Authors: Huxley LGH
Published: June 2011

A theoretical discussion is presented of the structure of a stream of electrons moving through a gas under the action of a uniform electric field. The treatment incorporates the phenomenon of longitudinal diffusion in which the coefficient DL can be different from the isotropic coefficient of diffusion D. The treatment also is not restricted to the case in which the aperture through which the stream enters the diffusion chamber is small. The solution satisfies the boundary condition n = 0 at the surface of the anode and everywhere on the cathode except over the plane of the source aperture. The theory therefore provides criteria for the validity of simplified solutions employed hitherto.
Mobility and Diffusion. I. Boltzmann Equation Treatment for Charged Particles in a Neutral Gas
Authors: Kumar Kailash , Robson RE
Published: June 2011

The conditions that usually prevail in drift tube experiments for the measurement of mobility and diffusion of electron and ion swarms are appropriate for the application of a linearized Boltzmann equation. Starting from such an equation, formulae for mobility and (anisotropic) diffusion coefficients are derived for the case where only elastic collisions are important. No restriction is placed on the masses of particles or on the nature of interaction potential. Results of earlier theories are shown to be special cases of the formulae obtained here. The intended application of the equations is mainly to the case of alkali metal ions in neutral rare gases, where numerical evaluation of the formulae is necessary. The m!lin features of some of the numerical procedures are discussed.
A New Model for the Lattice Dynamics of Alkali Halides
Authors: Wallace DC
Published: June 2011

Qualitative properties of the electronic band structure of a KCl crystal are used to derive a simple two-parameter model for the correlation function c(q, q') which arises in the theory of lattice dynamics. This function relates the adiabatic deformation of the electronic band structure to the vibration of the ion cores. Expressions for the dynamical matrices are derived. The model is ready for a direct computer evaluation of the phonon frequencies to test its validity.
Coherent Gyromagnetic Emission as a Radiation Mechanism
Authors: Melrose DB
Published: June 2011

The properties of coherent gyromagnetic emission of radiation which can escape from a source of astrophysical interest by a bi-Maxwellian distribution of nonrelativistic electrons (thermal velocities P 1.0 C and PII 0 c, and streaming velocity p, c) are considered. It is found that: (1) Coherent emission occurs only for Pio ;0;. PliO, and only for a more extreme anisotropy for waves close to their cutoff frequencies. (2) Coherent emission in the x-mode at the second harmonic, i.e. at OJ "'" 2Qe > OJp , is the dominant process except for p, > OJ~/Q; when coherent emission in the x-mode at he first harmonic, i.e. at OJ ~ Q. }> OJp , is possible and dominates. It is argued that these results are not strongly dependent on the choice of distribution function. It is pointed out that the use of the quasilinear equations can be justified in any astrophysical context but that the above properties apply even when the quasilinear treatment is not valid. Limitations imposed on the mechanism by the presence of absorption in the thermal plasma and by competing instabilities are shown to be relevant except for emission in the x-mode at the first harmonic.
Runge Solution of the Continuum Equations for Spherical Electrostatic Plasma Probes
Authors: Dorman FH
Published: June 2011

An approximate but convergent method is used to determine the electric potential and charged particle density near non-small spherical probes in a weakly ionized continuum plasma. Quantities determined partly by experiment (e, PP' yp) and partly from continuum theory (J +, J _) are introduced into three continuum differential equations which are then solved using Runge's method. The initial conditions must be estimated iteratively until the sheath solution joins smoothly to the quasi-neutral solution. Two different types of solution curves are discussed.
Corrigendum: Classification of Supernova Remnants and HII Regions from their Recombination Line Emission
Authors: Dickel JR , Milne DK
Published: June 2011

The galactic source number designations G35'6-0'4 and G35�5-0�0 in Table 1 should be interchanged. Thus G35'6-0'4 is the supernova remnant and G35�5 -0�0 appears to be an HII region. The authors thank Dr. T Velusamy for calling this error to their attention.
Possible Consequences of the Quark Model for Fragmentation Processes
Authors: Lai CS , Lo SY
Published: June 2011

The quark model is used to predict various sum rules for limiting fragmentation. In particular, the ratio of the cross section of p --+ p to that of n --+ n is found to be 9 : 4. An initial combination of the quark model with the generalized optical theorem is found to produce results which violate the quark-model selection rules and differ from experimental values by a factor of 103-106 ? A possible modification is proposed and further tests are suggested.
Diffusion of a Passive Scalar in a Two-dimensional Channel Flow
Authors: Manton MJ
Published: June 2011

The asymptotic representation of the distribution of a passive scalar within a two-dimensional channel flow is derived. The distribution is shown to be Gaussian with a skewness and longitudinal variance determined primarily by the mean shear. The distributions corresponding to both laminar and turbulent open channel flows are discussed.
8·8 GHz Radio Observations of 12 Suggested Supernova Remnants
Authors: Dickel JR , Milne DK , Kerr AR , Ables JG
Published: June 2011

Brightness distributions and flux densities at 8�8 GHz are presented for 12 small-diameter radio sources near the galactic plane. Each of these sources has been classified at one time or another as a supernova remnant. For one source, G295� 2 - 0�6, the flux density at 8�8 GHz confirms the thermal spectrum suggested by lower frequency measurements and indicates that it is not a supernova remnant. Another source, G309� 6+ 1�7, is thought to be extragalactic.
Radio Source Counts at 408 MHz
Authors: Mills BY , Davies IM , Robertson JG
Published: June 2011

Radio source counts at 408 MHz are investigated using the data from the first Molonglo catalogue (MC1) and an all-sky catalogue of strong sources. Earlier results are qualitatively confirmed. Possible explanations of the high exponent of the numberflux density relation between sources of strong and intermediate flux density are discussed briefly, but no firm conclusions seem possible.
Electron Drift Velocities in Air
Authors: Rees JA
Published: June 2011

The drift velocities of electrons have been measured in dry, carbon dioxide free, air at 293 K over the range 0�3 ,;:; E/N,;:; 12 Td for gas pressures between 10 and 50 torr. The results are compared with the data of Nielsen and Bradbury (1937) and Hessenauer (1967).
T?Matrix Perturbation Theory in the Three?Nucleon Bound State
Authors: Afnan IR , Read JM
Published: June 2011

A T-matrix perturbation method has been used to calculate three-body binding energies for two local potentials. The results obtained indicate that the method provides one of the most attractive ways of solving by computation the three-body bound state problem for realistic interactions.
Critical Phenomena in Systems of Finite Thickness. II. Ideal Bose Gas
Authors: N Barber Michael
Published: June 2011

The grand potential pressure of an ideal boson film which is infinite in d-1 dimensions (d > 2) but of finite thickness L in the dth dimension is analysed in the limit L -+ CX), to order L -d. Across the film (i) periodic, (ii) antiperiodic, and (iii) hard wall boundary conditions are applied. The corresponding shifts in the critical temperature Te.iL) are found to vary, for large L, as (i) L -d+2 for all d ;;:. 3, (ii) L-1, L -2lnL, and L -2 for d = 3,4, and ;;:. 5 respectively, and (iii) L -1lnL and L -1 for d = 3 and ;;:. 4. With hard wall boundary conditions, the critical temperature of a sufficiently thick film exceeds that of the bulk, while the other boundary conditions depress Te. The bulk critical region is asymptotically "rounded" on a scale set by the bulk correlation length matching the thickness L in accord with the scaling theory of finite-size effects.
Solution of Secular Determinants for Group IV And III?V Semiconductors by Symmetry Analysis
Authors: Joshua SJ , Morgan D
Published: June 2011

A brief discussion is given of the symmetry properties of the energy band structure and the method of constructing orthogonal matrices at high symmetry points for group IV and III-V semiconductors. By means of examples it is shown how to factorize the n x n secular determinant formed by using the pseudopotential form factors of Cohen and Bergstresser (1966), thereby permitting easy numerical solution.
Periodic Nonlinear Diffusion: An Integral Relation and its Physical Consequences
Authors: Philip JR
Published: June 2011

A general integral relation in steady periodic nonlinear diffusion is established through a Kirchhoff transformation. The time average e of the transformed concentration e satisfies Laplace's equation and may therefore be evaluated readily. Results for e not only serve as simple and exact checks on detailed numerical solutions of the nonlinear diffusion equation but also provide, immediately and exactly, the principal information often sought about these solutions. The results are especially simple in many steady periodic nonlinear diffusion problems where the time average of the flux density is everywhere zero and i!j is constant. The method is applied to examples in fluid mechanics and geophysics: spatially periodic laminar boundary layers, tidal influence and seasonal stream effects on groundwater levels, and soil temperature waves.
Collective Oscillations in Many Electron Atoms. I. Eigenvalues and Polarization
Authors: Monaghan JJ
Published: June 2011

Following the work of Bloch, the Thomas-Fermi model is extended to collective oscillations. The eigenfunctions and frequencies for radial and nonradial I = 1 modes are found. The calculated static polarization is compared with experiment, both for ions and neutral atoms, and the classical oscillator strengths are computed.
A Note on the Mixing of Angular Momentum in a Neutrally Buoyant Fluid
Authors: Manton MJ
Published: June 2011

The effect of turbulent mixing in a neutrally buoyant rotating fluid is considered in a region where the mean flow is axisymmetric. The separate actions of molecular and turbulent mixing are distinguished. It is shown that a rotating turbulent flow capable of mixing angular momentum must vary in the axial direction. In particular, it would seem that a secondary circulation is required for a flow to support turbulence over its whole volume. The relative roles of turbulence and secondary circulations in the mixing of angular momentum are discussed.
The Combined Effect of Rotation and Magnetic Field on Finite-Amplitude Thermal Convection
Authors: Van der Borght R , Murphy JO
Published: June 2011

The combined effect of an imposed rotation and magnetic field on convective transfer in a horizontal Boussinesq layer of fluid heated from below is studied in the mean field approximation. The basic equations are derived by a variational technique and their solutions are then found over a wide range of conditions, in the case of free boundaries, by numerical and analytic techniques, in particular by asymptotic and perturbation methods. The results obtained by the different techniques are shown to be in excellent agreement. As for the linear theory, the calculations predict that the simultaneous presence' of a magnetic field and rotation may produce conflicting tendencies.
Studies of D-Region Drifts During the Winters of 1970?72
Authors: Stubbs TJ , Vincent RA
Published: June 2011

Partially reflected radio waves have been used to study D-region drifts in the midwinter month of July for the years 1970--72. The drifts are shown to agree well with wind estimates at similar heights obtained using meteor radar techniques. The behaviour of the drifts is consistent with a strong tidal influence, and the nature of these tides is discussed with emphasis on the phase and amplitude variations in time and height. Comparison of the monthly mean drift profiles with wind models leads to a particularly good representation of the expected zonal drift profile. No evidence is found for any anomalous winter behaviour.
Synthesis Observations of Southern Radio Sources at 1410 MHz with the Parkes Interferometer. I. Instrument, Reduction, and Preliminary Results
Authors: Schwarz UJ , Cole DJ , Morris D
Published: June 2011

Modifications to the Parkes interferometer are described which allow synthesis observations to be made while still retaining the flexibility of frequent baseline changes. Details are given of the receiver with a phase stabilizing device and its performance, on-line computer control, and data processing. Preliminary observations with a resolution of l' of the two sources PKS 2152-69 and 2356-61 and possible optical identifications are discussed briefly.
"Parallel" Viscous Modification of the Resistive "Tearing" Instability in a Cylindrical Model of the Hard-Core Pinch
Authors: Marinoff GM
Published: June 2011

The influence of "parallel" viscosity on the resistive "tearing" mode in a cylindrical model of a plasma is investigated for a hard-core pinch. Iterative solutions of the basic equation indicate that the destabilization suggested by a previous cartesian model is not substantiated, and in fact under extreme shear there is slight stabilization. It is clear that geometrical effects must be properly included in order to obtain an accurate description of the role of parallel viscosity.
A Note on End Effects in Electron Drift Tube Experiments
Authors: Elford MT , Robertson AG
Published: June 2011

Experiments to test the influence of end effects on electron drift velocity measurements by the Bradbury-Nielsen time-of-flight method are described. A comparison of data taken at drift distances of 5, 10, and 50 cm in hydrogen and 5 and 10 cm in helium shows that over the EIN and pressure ranges investigated the results are independent of drift distance and that it is justifiable to consider this distance as that between the mid planes of the grids which terminate the drift chamber.
Australian Journal of Physics Astrophysical Supplements
Authors: Schmahl EJ
Published: June 2011

A description of nine moving type IV radio events is given, which completes the description of 24 such events observed with the 80 MHz Culgoora radioheliograph between September 1968 and November 1971. Radioheliograph data and radiospectrograms are presented together with related optical, X-ray, and microwave observations. Discussion is limited to the classification of the kind of moving source involved (advancing front, expanding arch, or isolated source) and a comparison with the characteristics of previously published events.
Singularities of the Triangle Diagram Vertex Function
Authors: Frederiksen JS , Woolcock WS
Published: June 2011

The definition of a singularity of an integral of Cauchy type is made precise under certain conditions. These conditions are shown to hold for the triangle diagram vertex function, and the positions of its singularities are studied.
Polarization Studies of Ground?State Radiation from the 2·21 and 2·73 MeV Levels of 27Al
Authors: Gardner PR , Baxter AM , Bell RAI , Carlson LE , Kean DC , Ophel TR , Spear RH
Published: June 2011

The E2/Ml mixing ratios of the ground-state )i-ray transitions from the 2�21 and 2� 73 MeV levels of 27 Al have been measured using a three-crystal Compton polarimeter in order to resolve discrepancies between previous experimental results for the 2� 73 MeV transition.
Photoelectric Setting Technique for Fringes of Equal Thickness
Authors: Ciddor PE
Published: June 2011

A theoretical and experimental study has been made of the photoelectric setting technique for fringes of equal thickness. The predicted departures of the theory from that for fringes of equal inclination have been confirmed and the parameters suitable for various practical applications have been calculated.
Transequatorial V.H.F. Transmissions and Solar-Related Phenomena
Authors: Heeran MP , Carman EH
Published: June 2011

Radio and ionospheric data are analysed to determine the influences of solargeophysical phenomena on transequatorial v.h.f. transmissions along a EuropeanSouthern African circuit. Results over six years show a close dependence on sunspot number. The observed correlation with sudden ionospheric disturbances indicates periodic solar-dependent defocusing of transequatorial signals by the ionosphere, while the combined effects of neutral winds and the position of the magnetic equator appear to control the seasonal behaviour of the transmissions.
Some Theoretical Considerations on Remote Probing of Weakly Scattering Irregularities
Authors: Briggs BH , Vincent RA
Published: June 2011

A basis is presented for the interpretation of electromagnetic or acoustic remote probing experiments in which back-scattering from horizontally stratified atmospheric irregularities is observed by radar techniques. The treatment takes into account geometrical factors and the polar diagrams of the transmitter and receiver. It is shown that single frequency observations give no information about the form of the irregularities if they are isotropic but that, if they are anisotropic with different horizontal and vertical scales, information about their horizontal scales may be obtained in some cases. The range of validity of some approximations introduced is tested by exact numerical computation for a typical example
Hydrogen Content of Young Stellar Clusters. I. Methods of Observation and Reduction
Authors: Tovmassian HM
Published: June 2011

Observations of 16 open galactic clusters in their continuum emission and at the neutral hydrogen line have been made with the Parkes 64 m radio telescope in an attempt to determine the total amount of hydrogen gas associated with them. In this, the first of a series of five papers, the observing procedure and the method of data reduction are described.
Hydrogen Content of Young Stellar Clusters. III. Clusters NGC3293, 6167, 6193, 6200, and 6204
Authors: Tovmassian HM , Shahbazian ET , Nersessian SE
Published: June 2011

The total amount of hydrogen associated with the O-type clusters NGC 3293, 6193, and 6204 and the suspected clusters NGC6167 and 6200 has been measured. Neither neutral nor ionized hydrogen was found to be associated with NGC 3293 and the visible nebula in this region is most likely associated with a single 07-type star, which does not appear to belong to the cluster, while an irregular expanding shell of neutral hydrogen probably surrounds the ionized nebula. The mass of hydrogen associated with NGC6193 does not exceed 500MQ? Neither neutral nor ionized hydrogen was detected at the position ofNGC 6204. The features detected by hydrogenline observations at the positions of suspected clusters NGC6167 and 6200 provide evidence that both visual groupings may be real clusters. The amount of neutral hydrogen probably connected with NGC6167 is ~ 1000 M Q ?
The Structures of Some Extragalactic Sources at 5000 MHz
Authors: Wall JV , Cole DJ
Published: June 2011

The large scale structures of 30 extragalactic sources have been investigated using the Parkes 64 m telescope at 5000 MHz. Contour maps are presented for the resolved sources and comparisons are made with observations at lower frequencies
On a Conjecture about Diffusion of Gaseous Ions
Authors: H Wannier Gregory
Published: June 2011

A previous conjecture by the author about the diffusion coefficient of gaseous ions is restated more precisely, thereby eliminating, in particular, an error of a factor of two which seemed to be contained in it in certain cases. The conjecture, which is essentially an extension of the Nernst-Einstein relation to situations not close to equilibrium, is made plausible by a Langevin-type derivation.
Helium Abundances in Four Galactic HII Regions from Radio Recombination Line Observations
Authors: Huchtmeier WK , Batchelor RA
Published: June 2011

Helium abundances in four galactic HII regions have been derived from radio recombination line observations
Elementary Particle Scattering Lengths and Resonances
Authors: Peaslee DC
Published: June 2011

An investigation is made of the relation between scattering lengths and resonances in a two-nucleon system. For resonances Eo near zero energy the usual determination of an effective optical potential in mesonic atoms is limited, and it is shown here that the scattering length can only be represented usefully as a sum over resonances of the compound system if the condition IEolDI ~ (PDo)! Is satisfied, where D is the average spacing of s-wave states, p the density of target nucleons and Do the Compton volume of the reduced system. This condition is seen to be valid for mr:, nK and KK interactions and these systems are considered in some detail. It is shown that knowledge of the level shifts of each of these examples can help resolve present uncertainties in associated boson structure.
Dipole States in 86Sr, 88Sr and 90Zr
Authors: Robertson RP
Published: June 2011

A shell model method for calculating dipole states in N > Z even nuclei is discussed. By assuming isospin to be a good quantum number, the spectrum resolves into two classes of states differing in isospin. Applications of this model to 88Sr and 90Zr essentially differ from previous calculations by the use of a new realistic force in the residual interaction. Dipole states in 86Sr are also investigated along with the effect of correlating the ground state wavefunction
On the Kelvin-Helmholtz Discontinuity in Two Superposed Plasmas
Authors: Kumar Bhatia Prem , Mendel Steiner Joseph
Published: June 2011

An investigation has been made of the effects of collisions with neutral particles on the stability of the plane interface separating two streaming superposed plasmas of uniform densities. It has been found that, whereas the ambient magnetic field has a stabilizing influence, a collision frequency has a stabilizing effect when it is small and a destabilizing effect when it exceeds a certain value.
Pictorial Presentation of Two-dimensional Calculations
Authors: Billington C , Kay NR
Published: June 2011

A method is described for presenting two-dimensional intensity calculations as halftone pictures on a high-resolution storage oscilloscope with the aid of a laboratory computer. Intensity calculations performed usually on medium or large computers are quantized to seven grey levels and translated economically into ASCII code for convenient transmission by line or storage on punched paper tape which is the input medium for the laboratory computer. The method is applied particularly to periodic pictures for which the unit cell need only be encoded once. Routine photographic procedures are described with several illustrations.
An Empirical Relation for the Evaluation of the Dielectric Relaxation Time of Certain Polar Liquids Using a Single Microwave Frequency
Authors: Sarma BS , Venkateswara Rao V
Published: June 2011

An empirical relation is proposed for the determination of the dielectric relaxation time .. of polar liquids with nearly spherical molecules from measurements of the dielectric constants at a single microwave frequency. The relation is obtained by introducing a concentration factor as a parameter in the expression for .. derived by Eyring et al. (1941). Its validity for suitable polar liquids is demonstrated by comparison of results with previously reported values. Thermodynamic parameters for a number of liquids at various concentrations have also been evaluated from experimental data using the relation.
Tetrads and the Gravitational-inertial Field
Authors: Marsh GE
Published: June 2011

The tetrad formulation of general relativity allows a non-tensorial decomposition of the gravitational field into two components which have been thought to represent the permanent and inertial parts. It is shown here that this division does not hold for arbitrary motions in a flat space-time, and therefore cannot be expected to hold in more general spaces.
Optical Identification of Southern Radio Sources. II.
Authors: M Lasker Barry , G Smith Malcolm
Published: June 2011

From a study of the fields of 11 southern radio sources, six identifications are suggested with faint galaxies and three with compact objects, while two fields appear blank to the limits of the photographs. Additional material for one previously identified field is also given.
Magnetization of Rare Earth Materials
Authors: Stewart AM
Published: June 2011

The formal procedure is demonstrated for calculating the magnetization of a rare earth material, in the mean field approximation, at arbitrary fields and temperatures when account is taken of crystal-field splittings, interionic exchange interactions and conduction electron polarization effects.
Study of Potential Interstellar Molecules: Nuclear Quadrupole Coupling Constants of the Nitrogen Atom in Pyrrole
Authors: Bolton K , Brown RD
Published: June 2011

The nuclear quadrupole coupling constants of the nitrogen atom in pyrrole have been redetermined by analysis of the hyperfine structure for several low J rotational transitions. The resulting values are x"" = 1'400�O'OO8 MHz and Xbb = 1�300�O�OO8 MHz. Small modifications to the previously reported rotational constants are given.
Collective Oscillations in Many Electron Atoms. II. Scattering and Slowing Down
Authors: Monaghan JJ
Published: June 2011

The slowing down of fast charged particles by their interaction with many electron atoms is considered using the hydrodynamic version of the Thomas-Fermi model. The agreement obtained with experiment is excellent over a wide range of parameters but worsens as the velocity of the charged particle decreases.
On the Theory of Electron Diffusion in Electrostatic Fields in Gases
Authors: Skullerud HR
Published: June 2011

The motion of electrons in a gas in the presence of large electron density gradients has been studied theoretically, starting from the two-term expansion of the Boltzmann equation. The effects of material boundaries have not been considered. An electron swarm released as a b-function in space and with an equilibrium energy distribution is found initially to develop as a spheroid with dimensions determined by the lateral diffusion coefficient. It subsequently passes through a stage involving a slowly decaying pear-shaped deformation, before ultimately becoming an ellipsoid with dimensions determined by the longitudinal and lateral components of the diffusion tensor. Numerical values cited in the literature for the long-term deviations from the mean square widths predicted by the diffusion equation have been found to be in error by factors of 10 or more.
Pressure Dependence and End Effects in Precision Ion Mobility Studies
Authors: Elford MT , Milloy HB
Published: June 2011

The mobilities of K + ions have been measured by the Bradbury-Nielsen method in He, Ar, H2 and N 2 at 293 K at pressures and E/Nvalues in the range 1�4-190 torr and 1-28 Td respectively. Three drift tubes were used with drift lengths of 3� 395, 9� 076 and 50�00 cm. The anomalous variation of the reduced mobility with E/ N at low values of E/ N reported by Elford (1971) has been shown to be due to the presence of charged surface layers on the first grid of the time-of-flight system. The dependence of the reduced mobility on pressure also reported by Elford has been confirmed, and an explanation of the pressure dependence in He, Ar and H2 is proposed in terms of the formation of ion-atom or ionmolecule complexes in orbiting resonant states. The zero-field reduced mobilities in the zero-pressure limit have been derived by a fitting procedure and found to be 21 �3 � O' 2, 2�64 � O� 02 and 12� 8 � O' 1 cm2 y-1 S-l for He, Ar and H2 respectively. The pressure dependence of the reduced mobility for K + ions in N2 is shown to be of a different form from the other gases investigated and to be due to the formation of the cluster ion K + . N2. The present data are consistent with the equilibrium constant of Beyer and Keller (1971) for the reaction K + + N2 + N2 +� K + . N2 + N2. The zero-field reduced mobility for K+ ions in N2 in the zero-pressure limit has been found to be 2�50�0�02 cm2 Y-1 s-1.
Equivalence of the Dicke Maser Model and the Ising Model at Equilibrium
Authors: Gibberd RW
Published: June 2011

The equilibrium properties of a system of N two-level atoms interacting with a quantized field, the so-called Dicke model of superradiance, are evaluated exactly by the 'thermodynamically equivalent Hamiltonian' method of Bogoliubov et at. (1957). The results are identical with those obtained by Hepp and Lieb (1973) and Wang and Hioe (1973). The thermodynamically equivalent Hamiltonian is shown to be equivalent to the mean field Hamiltonian of the Ising model, which indicates why the transition from the 'normal' to the 'superradiant' state of the Dicke model is similar to the transition from the disordered to the ordered state of the Ising model.
The Mechanism Responsible for 'Shadow' Type III Solar Radio Bursts. II. Absorption due to Ion Sound Turbulence
Authors: Melrose DB
Published: June 2011

The hypothesis is explored that ion sound turbulence generated by the exciting agency for type III bursts is responsible for shadow type III events. The possible absorption mechanisms are listed: the most favourable are the coalescence of transverse waves and ion sound waves into Langmuir waves or the decay of transverse waves into Langmuir waves and ion sound waves. These mechanisms can operate only if the background source emits at the fundamental plasma frequency and the absorbing region is directly above it (;$ 3 x 104 km). It is found that the event discussed by Kai (1973) can be explained in terms of such absorption with reasonable parameters, e.g. with an energy density in ion sound turbulence W' ~ 10-12 ergcm- 3 at frequencies co' ~ O�3cop! (where cop! is the ion plasma frequency).
A New Search for HI in the Southern Coalsack
Authors: Kerr FJ , Bowers PF , Harten RH
Published: June 2011

Since neutral hydrogen in dust clouds can often be detected from narrow self-absorption dips, two 21 cm profiles with a velocity resolution of 0�2 km s -1 have been obtained in the direction of the Southern Coalsack, in the hope of finding such a self-absorption dip. No neutral hydrogen could be detected. It is likely that most of the hydrogen in the Coalsack is molecular.
Energy Spectrum of 51V by the Intermediate Coupling Approach
Authors: Chung Woon-Hyuk
Published: June 2011

In recent years the nucleus 51 Y has been extensively studied, both experimentally by Horoshko et al. (1970), using the 48Ti(oc, py)51y reaction, and theoretically in terms of shell model calculations by many authors (McCullen et al. 1964; Horoshko et al. 1970; Lips and McEllistrem 1970). Mixed configuration shell model calculations by Lips and McEllistrem, in particular, have successfully reproduced the low-lying energy levels of5ly. However, strong coupling rotational model calculations by Malik and Scholz (1966) did not give satisfactory results. In the present work, the intermediate coupling unified model (Bohr and Mottelson 1953; Choudhury 1954) is applied to Sly. The purpose of this work is to show that the intermediate coupling model can successfully predict the low-lying energy levels of Sly.
Stability and the Extended Energy Principle of Plasma Physics
Authors: Seymour PW , James MK
Published: June 2011

The consequences of stress continuity across the plasma-vacuum interface on plasma stability are considered for a system having zero internal magnetic field, and it is shown that neutral stability is obtained at best. For the extended energy principle of
The Mobility of Negative Ions in Oxygen (293 K)
Authors: Elford MT , Rees JA
Published: June 2011

The Bradbury-Nielsen time-of-flight method has been used to measure the mobilities of six species of negative ions in oxygen at 293 K for gas pressures within the range 1� 3-22 torr and EI N values within the range 3-130 Td. The species were identified as
Ferromagnetism of SmCd
Authors: Stewart AM , Costa G , Olcese G
Published: June 2011

Measurements have been made of the magnetizations and resistivities of polycrystalline specimens of SmCd and LaCd. SmCd is found to be ferromagnetic with a Curie temperature of 194 K and a spontaneous moment of 0�05 PH per samarium ion at 77 K. Above this
Microwave Emission of the 211?212 Rotational Transition in Interstellar Acetaldehyde
Authors: Fourikis N , Sinclair MW , Robinson BJ , Godfrey PD , Brown RD
Published: June 2011

The 211?212 transition of acetaldehyde at 3195 �167 MHz has been observed in emission in SgrB2 with the Parkes 64 m telescope. Comparison of the intensities of the 110---> 11 and 211--->212 emission lines suggests that both transitions may be inverted.
The Parkes 2700 MHz Survey (Sixth Part). Catalogue for the Declination Zone ?30° to ?35°
Authors: Shimmins AJ , Bolton JG
Published: June 2011

This paper presents a catalogue of 939 extragalactic radio sources obtained from a sky survey at 2700 MHz. The area surveyed is between declinations - 30� and - 35�, nd covers all right ascensions except for two regions within approximately 10� of the ga
Supersonic Neutral Winds in an Outer Atmosphere. II. Effects of Variable Temperature
Authors: Gilbert NE , Cole KD
Published: June 2011

Using the concept of steady nozzle flow along a narrow tube, the effect a variable temperature has on achieving one or two critical points is considered for a neutral gas in a locally heated region of the outer atmosphere of a planet or star. An implicit finite-difference formula, which does not require restrictions on the temperature variation for convergence, is used to solve the general nozzle flow equation. The direct dependence on temperature variation of a single critical point at which the flow becomes supersonic is shown for a model in which the gravitational force component is almost constant.
A 1667 MHz OH Absorption Survey of the Southern Milky Way
Authors: Caswell JL , Robinson BJ
Published: June 2011

A search has been made at 1667 MHz for OH absorption against 105 strong continuum sources in the region 2650 < I < 352�, and data are presented for 33 sources showing absorption. The overall distribution of OH absorption in this galactic longitude range has been investigated by combining these results with measurements on 11 additional sources studied in earlier searches. Many of the sources showing 1667 MHz absorption have been observed at the other three 18 cm OH transitions and as a result 14 new satellite-line emission sources have been found.
Proton-induced Reactions with 9Be Between 6·5 and 9·5 MeV
Authors: Wild LWJ , Crinean GB
Published: June 2011

Excitation functions for the reactions 9Be(p,po)9Be, 9Be(p,P2)9Be*(2'43 MeV), 9Be(p,do)8Be and 9Be(p, cxo)6Li have been measured at 60�, 105� and 140�. With the exception of a resonance observed in the elastic scattering channel at 6� 5 MeV, no resonant structure was found in any excitation function