bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of the rate coefficient of the reactions H+ + 2H2 → H3+ + H2 and D+ + 2D2 → D3+ + D2 in a drift tube mass spectrometer
Authors: Graham E. , James D. R. , Keever W. C. , Gatland I. R. , Albritton D. L. , McDaniel E. W.
Published: February 2004

The rate coefficient of the reaction H+ + 2H2 → H3+ + H2 has been measured at a gas temperature of 300 °K and over a pressure range 0.25–0.50 torr. The transport properties and average energy of a given species of ion drifting in a gas in a uniform electric field are determined by E/N, where E is the electric field intensity and N is the gas number density. E/N is expressed in units of the townsend (Td), where 1 Td = 10−17 V · cm2. Our measurements were made over a range 25–50 Td, where the lower value corresponds to an average energy for the reacting H+ ions which is very close to the thermal energy of the H2 molecules at 300 °K. No systematic variation of the rate coefficient was observed over the range of E/N which was covered. The measurements were made with a drift tube mass spectrometer and involved the detailed analysis of the arrival time spectra of the product H3+ ion. The rate coefficient was evaluated to be (3.05 ± 0.15) × 10−29 cm6/sec. The same result was also obtained for the reaction D+ + 2D2 → D3+ + D2.
Magnetothermodynamics of gadolinium gallium garnet. I. Heat capacity, entropy, magnetic moment from 0.5 to 4.2 °K, with fields to 90 kG along the [100] axis
Authors: Fisher R. A. , Brodale G. E. , Hornung E. W. , Giauque W. F.
Published: February 2004

The magnetic moment of a 2.44 cm diam spherical single crystal of gadolinium gallium garnet has been measured with stabilized fields of 500, 1000, 2500, 5000, 10 000, 15 000, 25 000, 40 000, 65 000, and 90 000 G along the [100] axis, over the range 0.35 to 4.2 °K. The heat capacity was measured over similar ranges, except that 500 G was omitted and zero field included. The magnetic moment reached saturation at 0.35 °K and 90 000 G. The electronic and nuclear spin components of the heat capacity at 90 000 G could be separated from each other near 1 °K, thus locating a zero of entropy for the electronic system. By means of 34 adiabatics, corrected to isentropes, which crossed most of the isoerstedic heat capacity series, the entropies as a function of field and temperature were evaluated in terms of the zero reference. The sample has (0.4 ± 0.1) mole% excess entropy over the maximum R ln 8 for Gd3+ ion. Thus the sample must have contained 0.4 mole% excess Gd over the stoichiometric amount for Gd3Ga5O12. Using the correction factor 0.9960, the saturation value for Gd3Ga5O12 is found to be 39 095 G · cm3/mole Gd3+. This corresponds to a g = 2.000 ± 0.002. Smoothed correlated values of the heat capacity, entropy, enthalpy, internal energy, magnetic moment, and its differential isoerstedic temperature coefficient, differential isothermal magnetic susceptibility, and the isothermal work of magnetization have been tabulated over the ranges 0–90 kG and 0.5–4.2 °K.
Vibrational circular dichroism observed in crystalline α-NiSO4 · 6H2O and α-ZnSeO4 · 6H2O between 1900 and 5000 cm−1
Authors: Hsu Edward C. , Holzwarth G.
Published: February 2004

Axial circular dichroism (CD) of crystalline α-NiSO4 · 6H2O and α-ZnSeO4 · 6H2O is measured between 1900 and 5000 cm−1 at room temperature. Three CD bands with rotational strengths of 7 × 10−44, 3 × 10−44, and 1 × 10−42 erg · cm3 per molecule of water are observed at 5000, 4050, and 2300 cm−1, respectively, in α-NiSO4 · 6H2O. These CD bands are due to combination bands of H2O vibrations in the crystals. Substitution of H2O with D2O on α-NiSO4 · 6H2O shifts the 5000 cm−1 band to a frequency lower by the expected factor of 2. The 5000 and 4050 cm−1 CD bands are also observed in α-ZnSeO4 · 6H2O with the same intensities as in α-NiSO4 · 6H2O. Their positions are, however, shifted by 50 cm−1 toward higher energy. Due to strong absorption, the CD of fundamental vibrational modes of H2O in the crystals could not be measured. The CD is interpreted as a consequence of the linear k dependence of the effective charge of E mode optical phonons near k = 0.
Theory of inelastic collision: Extension to multiple turning point problems of uniform WKB theory
Authors: Eu Byung Chan
Published: February 2004

The uniform WKB theory developed in the previous papers of this series is extended so as to deal with cases of multiple turning point problems. It is found that the results of the previous studies are in general usable piecewise with appropriate initial conditions and reference equations in each interval. Two- and three-turning point problems occurring in two-channel inelastic collision processes are specifically dealt with in this paper.
Product distributions and rate constants for ion-molecule reactions in water, hydrogen sulfide, ammonia, and methane
Authors: Huntress W. T. , Pinizzotto R. F.
Published: February 2004

The thermal energy, bimolecular ion-molecule reactions occurring in gaseous water, hydrogen sulfide, ammonia, and methane have been identified and their rate constants determined using ion cyclotron resonance methods. Absolute rate constants were determined for the disappearance of the primary ions by using the trapped ion method, and product distributions were determined for these reactions by using the cyclotron ejection method. Previous measurements are reviewed and compared with the results using the present methods. The relative rate constants for hydrogen-atom abstraction, proton transfer, and charge transfer are also determined for reactions of the parent ions.
Compound state resonances in the collinear collision of an atom with a diatomic oscillator
Authors: Eastes Walter , Marcus R. A.
Published: February 2004

Compound state resonance effects are reported in exact, numerical calculations of the collinear collision of a particle with a harmonic oscillator with a Morse interaction potential. They are shown to be due to the formation of a long-lived complex or quasibound state and are much more narrow than resonances reported previously for this type of system. The stable eigenvalues resulting from a variational calculation with a bound state basis set are found to be in excellent agreement with the resonance energies, and such a variational calculation is a good way of locating these resonances.
ESR and ENDOR measurements on glyclglycine HNO3 x irradiated at 4.2°K
Authors: Rustgi Surendra N. , Box Harold C.
Published: February 2004

ESR and ENDOR spectroscopy were used to observe the effect of ionizing radiation on single crystals of glycylglycine HNO3 x irradiated at 4.2°K. The paramagnetic species NO32− and NO2 are formed. The N14 hyperfine and quadrupole coupling tensors were determined from the ENDOR spectra, and the g tensors were determined from ESR spectra for both species. A mechanism of NO2 formation is suggested which involves transfer of a proton to NO32− and formation of OH−.
Simple and useful group theoretical remark to simplify the vibrational force matrix
Authors: Sieskind Manuel
Published: February 2004

A simple method based on the linear character of the derivation's operators allows the relations between the elements of the force matrices occurring in vibrational problems to be obtained easily.
Electronic quenching of Al and Ga atoms isolated in rare gas matrices
Authors: Ammeter J. H. , Schlosnagle D. C.
Published: February 2004

Aluminum and gallium atoms have been trapped in Ne, Ar, Kr, and Xe matrices and studied by optical and ESR spectroscopy at 4.2 °K and slightly higher temperatures. The results indicate that both metal atoms occupy axially distorted substitutional sites in all rare gas lattices. This elongated tetradecahedral MeX12 coordination is particularly stable for rare gas complexes of Group III metal atoms exhibiting a single unpaired electron in their outermost p shell. From the ESR data large splittings of the aluminum and gallium p shells have been derived increasing from [inverted lazy s] 1600 cm−1 in neon to [inverted lazy s] 3200 cm−1 in xenon for both atoms. The corresponding Jahn-Teller stabilization energies EJT (increasing from [inverted lazy s] 1.5 kcal/mole for MeNe12 to [inverted lazy s] 3.0 kcal for MeXe12) can be explained by the ``σ-π'' effect: The van der Waals interatomic correlation energy is maximized, and the repulsive exchange energy is minimized by attraction of the equatorial ligand atoms to the metal center and repulsion of the remaining ligands from the σ antibonding axial positions. The 2S ← 2P[(n + 1)s ← np] electronic transitions are shifted by [inverted lazy s] + 1000 cm−1 (MXe12) to [inverted lazy s] + 6000 cm−1 (MNe12) relative to the free metal atom values. The ESR spectra exhibit axial symmetry, show effects of preferential orientation, and demonstrate almost complete quenching of the free atom angular momentum in each case. The basic features of the g values and the metal hyperfine tensor (and of their strong dependence on the matrix and on temperature) can be understood within a simple crystal field model, but there are significant deviations. The introduction of orbital angular momentum and spin-orbit reduction factors resulting from orthogonalization of the metal p orbitals to the valence shells of the surrounding rare gas atoms removed a large part of the discrepancies, but quantitative agreement with experiment could be obtained only when the dynamic Jahn-Teller effect was taken into account. In order to establish the geometries of the rare gas cages surrounding the trapped metal atoms, numerical calculations of orbital and spin-orbit reduction factors were performed for various sites in the rare gas lattices. For the determination of the vibronic quenching parameters a slight extension of Ham's second order theory of an orbital triplet interacting with an e2g vibrational mode was required. Our results indicate a remarkable stability of the Al and Ga rare gas complexes. Indeed, from the results of Baylis' semiempirical calculations it can be concluded that atoms with singly occupied p shells form the strongest van der Waals complexes with rare gas atoms among all atoms in the periodic table.
ENDOR studies of the superhyperfine couplings of hydrogen-bonded protons. I. Carboxyl radical anions in irradiated L-alanine single crystals
Authors: Muto Hachizo , Iwasaki Machio
Published: February 2004

The carboxyl radical anion trapped in an irradiated single crystal of L -alanine was studied. ENDOR techniques were used to clarify the origin of the transferred proton in this anion. The hyperfine tensor of the transferred proton and the superhyperfine tensors of the hydrogen-bonded protons in the neighboring NH3+ groups were determined. The results show that the transferred proton forms a normal covalent bond with the carboxyl oxygen atom and is located outside the COO plane. The direction of the O–H bond formed by the transferred proton is approximately parallel to one of the three hydrogen bonds in the undamaged crystal. This suggests that this proton is transferred across this particular hydrogen bridge. In addition, the large positive isotropic coupling of the transferred proton was accounted for by the structure of the protonated anion.
Perturbation correction for the free energy and structure of simple fluid mixtures
Authors: Lado F.
Published: February 2004

Adapting an analysis due to Morita and Hiroike and Green which led to the hypernetted-chain (HNC) integral equation, we obtain an expression for the difference in free energy between a perturbed mixture with potentials φα β = φα β(0) + φα β(1) and a reference mixture with potentials φα β(0) a result which is rendered computable by an HNC-type approximation. No further approximations are required to compute the corrected pair distribution functions of the perturbed mixture, but a proposed second approximation yields a particularly simple solution. This work generalizes earlier results on single-component fluids.
Pressure and concentration effects on the molecular reorientation in water-dioxane mixtures
Authors: Lee Y. , Jonas J.
Published: February 2004

The pressure and concentration dependences of the deuteron spin-lattice relaxation times and viscosity have been measured in D2O-dioxane and H2O-dioxane-d8 mixtures up to 4.5 kbar at 30, 40, and 50°C. The experimental data interpreted in terms of the parameter κ introduced in the theory of the rotational relaxation in liquids by Kivelson, Kivelson, and Oppenheim. The results show that the reorientation of the D2O molecules at 1 bar can be described by the Debye equation, i.e., κ is equal to one and independent of the composition of the mixture. On the other hand, the parameter κ for the reorientation of dioxane-d8 is of the order of 0.1 and dependent on the composition. Both for D2O and dioxane-d8 the parameters κ decrease with increasing pressure. The higher the dioxane content in the mixture the larger the change in κ with pressure. This indicates that increasing pressure diminishes the coupling between the reorientational and translational motions in this binary system. Phase transitions were observed under high pressure for the solutions of moderate and high dioxane concentrations. A brief discussion of the pressure, temperature, and concentration behavior of the reorientational correlation times in the solid phase is also given.
Dissociative attachment from the O2(a1Δg) state
Authors: Burrow P. D.
Published: February 2004

The dissociative attachment cross section for production of O− by electron impact on the metastable O2(a1Δg) state is studied. The cross section is found to be 4.6 ± 1.3 × 10−18 cm2 at its maximum. From the measured energy dependence, we infer that the dissociative attachment process takes place through the O2−(2Πu) state as in the case of O− production from the O2 ground state. The information thus obtained is used to estimate the portion of the cross section for excitation of the a1Δg state by electron impact which proceeds via the O2−(2Πu) state. This mechanism is shown to account for the location and approximate magnitude of the maximum in the excitation cross section. Finally, information is obtained concerning the cross section for positive ionization of the O2(a1Δg) state near threshold.
Diffraction pattern and structure of molten BeF2–LiF solutions
Authors: Vaslow F. , Narten A. H.
Published: February 2004

X-ray diffraction data on the liquid systems (BeF2)x(LiF)(1−x), with x = 1, 1/2, 1/3, 1/5, and 0, are presented and analyzed to yield average nearest-neighbor distances and coordination numbers. The values obtained for the melts are in good agreement with results derived from molecular dynamics calculations.
Excited state electronic structure and dynamics in sym -tetrazine vapor
Authors: McDonald J. R. , Brus L. E.
Published: February 2004

The excited state dynamics of sym -tetrazine are investigated following dye laser excitation into single vibronic levels of the 1B3u and 3B3u states. The lifetime of the 1B3u state, τf ≤ 100 nsec, is probably controlled by unimolecular internal conversion into the 1Ag ground state. Intersystem crossing is not observed at low pressure and is not induced by hard sphere collisions. The 3B3u → 1Ag phosphorescence, τp = 72 ± 2 μsec, is reported for the first time. Theory suggests that this lifetime is not controlled by radiationless intersystem crossing, and it may be that the 3B3u lifetime is controlled by a radiative transition to a possible lower lying 3B1g or 3B2g state. Energy transfer experiments from triplet p -benzoquinone to 3B3u sym -tetrazine confirm the lifetime and spin-forbidden character of the phosphorescence emission.
Propagation of electromagnetic waves in anisotropic crystals: Origins of the angular dependence of the Davydov splittings
Authors: Fulton Robert L.
Published: February 2004

The preceding discussion of the propagation of electromagnetic fields in anisotropic crystals is extended to include crystals having many molecules per unit cell. The susceptibility, which enters the equation of motion for the vector potential, is evaluated for a simple model of an anisotropic crystal and found to depend on the direction of propagation k̂ in the long wavelength limit k → 0. When the susceptibility is specialized to a description of Frenkel excitons, the resonant energies and the Davydov splittings are shown to exhibit a dependence on k̂ as predicted by Fox and Yatsiv. The dielectric tensor ε, identified by deriving the customary Maxwell equations from the equation of motion for the vector potential, is found to be independent of k̂. The angular dependence of the Davydov splittings is thus predicted by the Fresnel equations of classical optics and is not unique to excitons. If such angular dependence is not observed, the customary Maxwell equations are not valid. A brief discussion of the failure of the model to give a proper account of interband transitions is given.
Photodetachment of electrons from large molecular systems: Cyclopentadienide and methylcyclopentadienide ions. An upper limit to the electron affinities of C5H5· and CH3C5H4·
Authors: Richardson Jeffery H. , Stephenson L. M. , Brauman John I.
Published: February 2004

The relative cross sections for the gas phase photodetachment of electrons have been determined for cyclopentadienide ions in the wavelength region 270–670 nm (4.59−1.85 eV) and for methylcyclopentadienide ions in the wavelength region 270–730 nm (4.59−1.70 eV). An ion cyclotron resonance spectrometer was used to generate, trap, and detect the negative ions and a 1000 W xenon arc lamp with a grating monochromator was employed as the light source. Both ions exhibited a monotonically increasing cross section over the entire wavelength region; consequently, only upper limits to the electron affinities could be determined: E.A. (C5H5 ·) ≤ 1.84±0.03 eV and E.A. (CH3C5H4 ·) ≤ 1.67±0.04 eV.
Collision of an atom and a diatomic. A semiadiabatic approximation
Authors: Storm David , Thiele Everett
Published: February 2004

A semiadiabatic approximation is used to compute transition probabilities for vibrational excitation in the model problem of a collinear collision between a particle and a harmonic oscillator interacting via a repulsive exponential potential. The semiadiabatic approach differs from the previously studied adiabatic approach in that only part of the static interaction is included in the definition of the unperturbed Hamiltonian. The advantage is that the eigenfunctions of the semiadiabatic operator are more easily obtained than those of the adiabatic operator. The perturbation inducing transitions between the states of the semiadiabatic Hamiltonian is the kinetic energy operator and the remainder of the static potential. A rapid method is developed for estimating transition probabilities with an accuracy comparable to that obtained by using the corrected distorted wave approximation.
Diatomics-in-molecules potential energy surfaces. II. Nonadiabatic and spin-orbit interactions
Authors: Tully John C.
Published: February 2004

A simple procedure is described for calculating spin-orbit and nonadiabatic interactions by an extension of the diatomics-in-molecules approach. The method can be easily applied to a large number of polyatomic systems and will hopefully be of value in obtaining qualitative and quantitative descriptions of many important molecular collision processes which involve more than one potential energy surface. Results are presented for two such processes, the quenching of Li(2 2P) by H2 and the reaction of F atoms with H2.
Semiclassical S-matrix theory. VI. Integral expression and transformation of conventional coordinates
Authors: Marcus R. A.
Published: February 2004

Sometimes, as in reactive systems, action-angle variables are not conveniently defined at all points of the trajectory and recourse must be made to conventional coordinates. A simple canonical transformation converts the latter to coordinates of which one is time and the remainder are constant along the trajectory. The transformation serves to remove the singularities of the semiclassical wavefunction at the turning points of the trajectory. It yields, thereby, an integral expression for the S matrix by having produced wavefunctions which can be integrated over all space. The result supplements that of Paper III [R. A. Marcus, J. Chem. Phys. 56, 311 (1972)], which was derived for systems for which action-angle variables could be defined throughout the collision.
Semiclassical transition probabilities by an asymptotic evaluation of the S matrix for elastic and inelastic collisions. Bessel uniform approximation
Authors: Stine J. R. , Marcus R. A.
Published: February 2004

It has been observed in the past that the usual Airy uniform approximation gives probabilities greater than one, especially for near elastic collisions. By mapping the phase onto −ζ cos y + ky + A rather than (1/3)y3 − ζy + A one obtains a uniform approximation involving Bessel functions of the first kind, which approaches unity for the elastic collision. This Bessel uniform approximation is no more complicated than the Airy and also gives good agreement with exact quantum results, even if probabilities are large.
Vacuum ultraviolet absorption spectra of the van der Waals molecules Kr2 and ArKr
Authors: Tanaka Y. , Yoshino K. , Freeman D. E.
Published: February 2004

The vacuum ultraviolet absorption spectrum of the van der Waals dimer Kr2 has been photographed in the region 1050–1260 Å by a 6.65 m spectrograph with the argon continuum as background source. Eight band systems, four well-developed and four rather fragmented, are observed. Vibronic analyses of the former four systems reveal that their upper states are correlated to separated atom limits in which one Kr atom is excited to various levels of configuration 4p55s. Upper molecular state designations and dissociation limits are discussed. The four fragmented band systems are energetically close to various KrI levels of configuration 4p55p. A similar study of a mixture of argon and krypton yields five groups of diffuse bands attributed to ArKr; two of these band groups are close to KrI resonance lines. The ground electronic state of Kr2 supports 16 bound vibrational levels of which nine (ν″ = 0–8) are involved in the observed vibronic structure and the other seven inferred from an extrapolation procedure based on an assumed inverse sixth power long-range potential. The spectroscopic values for the well depth 138.4 ± 1.9 cm−1 and the zero-point vibrational energy 11.6 ± 0.1 cm −1 are in accord with recent results derived from molecular scattering experiments.
Lattice energies of cubic alkaline-earth oxides. Affinity of oxygen for two electrons
Authors: Cantor Stanley
Published: February 2004

The lattice energies of these crystals were calculated from equations based on the Born model and containing terms accounting for van der Waals interactions. The results were, in kilocalories per mole: MgO, −905; CaO, −815; SrO, −767; BaO, −736. These lattice energies, when combined with appropriate thermochemical data, yielded 149 ± 8 kcal/mole for the increase in enthalpy of the reaction of atomic oxygen with two electrons. This value is less than most values previously computed for this process. The decreased value is attributed to the higher, more accurate compressibilities used in evaluating the lattice energies of these oxides.
Patterns of zonation of assemblages of the Lutjanidae, Lethrinidae and Serranidae (Epinephelinae) within and among mid-shelf and outer-shelf reefs in the central Great Barrier Reef
Authors: Newman Stephen J. , Williams David McB. , Russ Garry R.
Published: February 2004

Visual censuses were used to quantify the distribution and abundance of the Lutjanidae, Lethrinidae and Serranidae in three reef zones (windward reef slope, lagoon, back reef) of three reefs on the mid shelf and three reefs on the outer continental shelf in the central region of the Great Barrier Reef. Significant spatial variability was identified in the abundances of many species between locations (outer-shelf and mid-shelf communities), between reefs (high-abundance v. low-abundance reefs), and within reefs (characteristic communities within zones on individual reefs). Species of the Lutjanidae, Lethrinidae and Serranidae were found to occur in assemblages that were characteristic of major zones (windward reef slopes, lagoons and leeward back reefs), this pattern being consistent within and among shelf locations. Care will need to be taken in determining the appropriate spatial scales of sampling in any future experiments (e.g. manipulations of fishing pressure) to ensure that the effects of smaller-scale spatial differences are not confounded when larger-scale comparisons are made.
Biochemical genetics and recognition of a western stock of the common gemfish, Rexea solandri (Scombroidea : Gempylidae), in Australia
Authors: Colgan Donald J. , Paxton John R.
Published: February 2004

Protein electrophoresis and analysis of restriction fragment polymorphism in mitochondrial DNA (mtDNA) provided information on population/stock structure of Rexea solandri. Two distinct Australian stocks are evident, with one (AAT-2) of 36 enzymatic loci and all 11 mtDNA digestion profiles showing highly significant differences between eastern and southern/western Australian specimens. The split is at the western end of Bass Strait, with limited mixing off western Tasmania. No external characters were found that would allow determination of the provenance of an individual fish. Stock distinction between eastern Australian and New Zealand fish is less clear; some differences, usually statistically non-significant, in genetic frequencies were found and some rare allozymic or restriction fragment variants were found in one or other but not both regions. Estimates of gene flow suggest that only tens of individuals per generation migrate between the regions. In an experiment on tissue deterioration, after six days of exposure out of doors, significant amounts of intact mtDNA were present in all tissues, and all fragments of the HINF 1 phenotype were clearly scorable. Of 19 enzymes tested, only three showed reduced activity on Day 6. Gonad and muscle tissues were more resistant to degradation than was liver tissue.
Contributions of sugar cane and invasive pasture grass to the aquatic food web of a tropical lowland stream
Authors: Bunn Stuart E. , Davies Peter M. , Kellaway Dominica M.
Published: February 2004

In-stream ecosystem processes in a tropical lowland stream in far north Queensland were studied by measuring open-system community metabolism and analysing stable isotopes. The stream catchment, like many others in this region, has been extensively cleared for the cultivation of sugar cane, and in the absence of riparian shading, aquatic and semi-aquatic plants choke the stream channel. Stream community metabolism switched between autotrophy and heterotrophy, depending on the degree of cloud cover. Successive cloudy days may be sufficient to result in anoxia in the stream, particularly in the benthos, where limited oxygen penetration into the sediments was recorded. Stable-isotope data indicated that little of the primary production from sugar cane or other C4 plants was transferred into the aquatic food web. The only significant contribution of C4 carbon was to the diets of some larger predatory fish, which must be directly dependent on terrestrial prey. In the absence of significant riparian inputs of C3 carbon, it appears that in-stream primary production supported the aquatic invertebrate community. Restoration of disturbed stream systems such as this one must include the establishment of appropriate riparian species for the reduction of excessive in-stream primary production and the supply of detritus for the maintenance of aquatic food webs.
Occurrence of aggressive mechanisms during interactions between soft corals (Octocorallia : Alcyoniidae) and other corals on the Great Barrier Reef, Australia
Authors: Griffith J. K.
Published: February 2004

This study found that on two reefs of the Great Barrier Reef, Australia, most coral colonies within 10 cm of a soft coral colony were interacting to the detriment of one or both colonies. Soft corals were more likely to interact with neighbouring hard corals than with other soft corals. The relative infrequency of ties indicated that two coral colonies were rarely equal competitively. Allelopathy and simple overgrowth were the major aggressive mechanisms of alcyoniids. Soft corals tended to simply overgrow neighbouring hard corals but used allelochemicals more frequently when the neighbour was another soft coral. Other factors influencing the type of aggressive mechanism used included the size of the neighbouring colony. The importance of this to a coral reef community after events such as Acanthaster planci infestations is discussed.
Estimating the size-transition matrix for Tasmanian rock lobster, Jasus edwardsii
Authors: Punt André E. , Kennedy Robert B. , Frusher Stewart D.
Published: February 2004

Assessment of the southern rock lobster
(Jasus edwardsii) resource in Tasmania is based on a
size-structured population dynamics model. One of the most important inputs to
this model is the set of matrices that represent the season-specific
probabilities of a lobster growing from one size-class to another. These
matrices are estimated from tag–recapture data within a
maximum-likelihood estimation framework. Measures of precision are determined
from the asymptotic variance–covariance matrix. Various alternative
models are contrasted for one site in the south-east of Tasmania, and a best
model is selected by the likelihood ratio test. The growth model used is based
on a generalization of the von Bertalanffy growth equation. Growth rates
differ markedly among regions around Tasmania, being slowest in the south and
fastest in the north. Growth of legal-size males is noticeably faster than
that of legal-size females. It is shown that ignoring the effects of
selectivity can lead to biased estimates of growth rate. An extension to the
method is presented and applied that estimates size-specific selectivity in an
attempt to eliminate this bias.
Biological tags as moult indicators in Panulirus cygnus (George)
Authors: Melville-Smith R. , Jones J. B. , Brown R. S.
Published: February 2004

Laboratory and field trials were employed to examine the feasibility of using
biological tags as moult indicators. Twenty-four animals were tagged with
epidermal implants and held in aquaria for 2 years and 8 months before the
tags were removed. Five tags failed to form useful cysts and one tag was
damaged during processing. The remaining 18 lobsters moulted between three and
six times, with this moulting record being accurately verified by 15 of the
biological tags and incorrectly interpreted (by one moult) in one case. Two
tags produced inconclusive results. Biological tags were tested in the field
in the Fremantle area, with 132 animals being recaptured out of 1336 tagged.
Eleven tags proved impossible to read, eight failed to form cysts, and the
balance recorded up to six moults during the release period. Animals in the
size range 60–80 mm carapace length (CL) recorded two moults per year,
one in February–April and a second before the mid-November start to the
fishing season. Females grew significantly less per moult than did males in
the same size category (60–85 mm CL), and both sexes showed
significantly smaller increments for animals ≥85 mm CL at release.
Behaviour and growth of captive spiny lobsters (Panulirus argus) under the risk of predation
Authors: Lozano-Alvarez Enrique , Spanier Ehud
Published: February 2004

The behaviour and growth of captive spiny lobsters
(Panulirus argus) under and not under the risk of
predation was investigated in four 9-m2 sea enclosures:
two ‘predator enclosures’ (P1 and P2) into which one predator, the
triggerfish Balistes vetula, was introduced; and two
‘non- predator enclosures’ (NP1 and NP2). Each enclosure contained
a 1-m2 artificial shelter, and lobsters were provided
with food ad libitum for 45 days, measured then left for
a further 30 days with a reduced food supply. Inter- and intraspecific
interactions and shelter use were recorded by means of underwater observations
during day and night. Daytime shelter use by lobsters and fish was highest at
noon and in the early morning. Activity of lobsters outside the shelters
peaked around midnight in all four enclosures. Lobsters in P2 showed more
activity and less shelter use than did those in all other enclosures. More
predatorprey interactions were recorded in P1 than in P2, whereas
intraspecific interactions were more prevalent in P2 than in the other three
enclosures combined. Growth of lobsters was significantly higher only in NP1.
The difference in lobster behaviour and survival between the two predator
enclosures may be associated with the initial timing of shelter occupancy by
the predators.
A fisheries management success story: the Gisborne, New Zealand, fishery for red rock lobsters (Jasus edwardsii)
Authors: Breen Paul A. , Kendrick Terese H.
Published: February 2004

After individual quotas were imposed in 1990, the fishery for
Jasus edwardsii in the Gisborne area showed continuing
declines in catch and catch rate to 1993, and the total quota could not be
caught in this area. There were few legal-sized but many sublegal-sized
lobsters. Pots caused mortality of sublegal lobsters through handling,
pot-related Octopus predation, and thefts from
commercial pots.
The industry, in conjunction with recreational fishers and Maori, developed a
scheme to address these problems. The aim was to increase landed value to
compensate for quota reductions, and to do this by landing more lobsters in
winter (when prices were higher) and landing smaller lobsters (which had a
higher unit price). A shortened season was designed to reduce pot-related
mortality.
Part of the scheme—a proposal to reduce the minimum legal size of male
lobsters—caused controversy. However, the package was evaluated with a
simple model and then accepted by the Minister of Fisheries. Results were
substantially increased catch rates since 1993, a successful shift to a winter
fishery, and a shift in length frequencies toward larger sizes. A simple
size-structured model fitted to the fishery data and used to evaluate future
management options is also described.
Contrasting sizes at sexual maturity of southern rock lobsters (Jasus edwardsii) in the two Victorian fishing zones: implications for total egg production and management
Authors: Hobday D. K. , Ryan T. J.
Published: February 2004

Fecundity (F) of Jasus edwardsii
Hutton (Decapoda:Palinuridae) in the two Victorian fishing zones (Eastern and
Western) was estimated from egg masses collected from 98 mature females
(97–164 mm carapace length, CL) and was found to be related to carapace
length (CL) by the equation F =
0·0316L3.359
(r2 = 0·8539;
n = 571). Size at onset of sexual maturity (SOM),
estimated from samples of the commercial catch (n
= 3891) and analysed to determine the smallest size class in which
50% of females were carrying eggs or possessed ovigerous setae, was
lower in the Western Zone (90 mm CL) than in the Eastern Zone (112 mm CL).
Fecundity and SOM estimates and length frequencies in the commercial catch
were used to estimate the relative reproductive potential (RRP) of each
5-mm-CL size class. The maximum RRP in the Western Zone was attributed to the
size classes of 105 (38%) and 110 mm CL (25%), whereas the
maximum RRP in the Eastern Zone was attributed to the size classes between 130
(40%) and 135 mm CL (16%). This study indicates that the current
minimum legal size limits need to be reassessed and that separate management
strategies for the two zones need to be considered.
Habitat use and growth of juvenile ornate rock lobsters, Panulirus ornatus (Fabricius, 1798), in Torres Strait, Australia
Authors: Dennis D. M. , Skewes T. D. , Pitcher C. R.
Published: February 2004

Habitat use and growth of juvenile (8–90 mm carapace length, or CL)
ornate rock lobsters, Panulirus ornatus, were described
with the aid of information from field surveys in Torres Strait and from a
laboratory growth experiment. In north-western Torres Strait, small juveniles
(<40 mm CL) sheltered in solution holes in the seabed that matched their
body size. Most shelters were in limestone pavement and near macroalgae.
Larger juveniles sheltered in both solution holes and crevices. Juveniles were
found at all depths sampled (3–21 m), and densities of juveniles were
uniform over this depth range. The average density of juveniles in the study
area in 1992–93 was 63 ha-1. Size distributions of
juveniles sampled during August 1992 to March 1993 showed that early growth
was 1·4 mm CL week-1. A laboratory trial to
examine the effect of temperature on growth showed that juveniles grew
31% faster at 30°C (0·88 mm CL week-1)
compared with growth at 26°C (0·67 mm CL
week-1) as a result of shorter moult intervals in large
juveniles. Size distributions of juveniles sampled at mid year between 1990
and 1995 showed that 10–20% reach legal size (75 mm CL) about one
year after settlement.
Hydrodynamic decoupling of recruitment, habitat quality and adult abundance in the Caribbean spiny lobster: source - sink dynamics?
Authors: Lipcius R. N. , Stockhausen W. T. , Eggleston D. B. , Jr L. S. Marshall , Hickey B.
Published: February 2004

Marine species possess dispersive stages that interconnect subpopulations,
which may inhabit ‘source’ and ‘sink’ habitats, where
reproduction and emigration either exceed or fall short of mortality and
immigration, respectively. Postlarval supply, juvenile density and adult
abundance of the Caribbean spiny lobster,
Panulirus argus, were measured at four widely separated
sites spanning >100 km in Exuma Sound, Bahamas. Adult abundance was lowest
at a site with the highest postlarval supply and little nursery habitat;
hence, it was tentatively classified as a sink. Circulation in Exuma Sound is
dominated by large-scale gyres which apparently concentrate and advect
postlarvae toward the nominal sink. The remaining three sites, including one
marine reserve, had higher adult abundances despite lower postlarval supply,
and are therefore tentatively classified as sources. Postlarval supply is
probably decoupled from adult abundance by physical transport. Adult abundance
is likely decoupled from postlarval supply by the effects of varying habitat
quality upon postlarval and juvenile survival, as indicated by non-significant
differences among sites in juvenile density. It appears that some sites with
suitable settlement and nursery habitat are sources of spawning stock for
Panulirus argus, whereas others with poor habitat are
sinks despite sufficient postlarval influx.
Nocturnal foraging of the Caribbean spiny lobster (Panulirus argus) on offshore reefs of Florida, USA
Authors: Cox Carrollyn , Hunt John H. , Lyons William G. , Davis Gary E.
Published: February 2004

During night dives along randomly selected transects across sand, seagrass,
and rubble on the reef flat of Looe Key, a spur-and-groove coral reef, spiny
lobsters (Panulirus argus) from dens on the forereef
were observed foraging on the reef flat, particularly on the extensive rubble
ridge and also relatively frequently in Thalassia.
Subsequent sampling of the rubble revealed hundreds of taxa of appropriate
prey items, many at high densities; the density of
Cerithium litteratum, a favoured food item, was as high
as 180 individuals m-2. Arthropods, especially spider
crabs (Pitho spp.), were common in seagrass. Gut
contents of 75 intermoult lobsters caught on offshore reefs at Biscayne
National Park and Dry Tortugas National Park included a myriad of prey items,
predominantly molluscs—especially gastropods (49%), chitons
(15%), and bivalves (11%)—and arthropods (12%);
many of the species in lobster guts were rubble dwellers, but some guts
contained multiple prey peculiar to seagrass and sand. It is concluded that
Panulirus argus can forage successfully wherever
suitable prey items, especially molluscs, are abundant. However, where a wide
range of substrata, including rubble, is available, rubble is preferred
because of its abundant, accessible prey.
Relative influence of environmental factors and processing techniques on Panulirus cygnus morbidity and mortality during simulated live shipments
Authors: Spanoghe Patrick T. , Bourne P. K.
Published: February 2004

In this study, conducted in collaboration with the Western Australian rock
lobster industry during the 1992–93 fishing season, daily records were
made on morbidity and mortality of western rock lobsters,
Panulirus cygnus, held in commercial shipping (export)
cartons. The aims were to measure the rates of morbidity + mortality and
to identify patterns of correlation of morbidity + mortality rates for a
range of environmental variables recorded by the processors. In three
processing units, the rate of morbidity + mortality in simulated live
shipments averaged 5á2% (±0·6), with a highly
significant difference (P<0·001) between
processing units. Three factors, holding time in export cartons, ambient
temperature within the export cartons and chilling period before packing
lobsters, had the greatest influence on the rate of morbidity +
mortality. Morbidity + mortality rate of animals held for 30–36 h
(10·4 ± 2·3%) was twice that of animals held for
20–24 h (5·2 ± 0·6%). A positive significant
correlation (r = 0·25,
P = 0·001) was identified between
morbidity + mortality rate and the internal carton temperature.
Aprolongation of the chilling period was reflected by improved survival,
possibly resulting from an anaesthesic effect of the chilling treatment.
Movements, Activity Patterns and Habitat Use of Feral Pigs (Sus scrofa) in a Tropical Habitat
Authors: Caley Peter
Published: February 2004

Movements, activity patterns and habitat use of feral pigs were studied in a tropical woodland habitat by radio-telemetry, live-trapping and hunter returns. The mean aggregate home-range size was 33.5 km2 for boars and 24.1 km2 for sows. Feral pigs were rather sedentary, with no tendency to disperse great distances from their initial home ranges. Pigs were most active at night, with peaks of activity in the late afternoon and early morning. Pigs preferentially used the riparian vegetation strip bordering major rivers, and grain crops, when available. The implications for the management of pigs are discussed.
Niche Partitioning by Two Sympatric Goshawks in the Australian Wet Tropics: Breeding-season Diet
Authors: Burton Andrew M. , Olsen Penny
Published: February 2004

In general, coexisting accipiters show low dietary overlap and clear morphological separation. However, most studies have been conducted in the Northern Hemisphere. In Australia, the two accipitrid goshawks, the grey goshawk, Accipiter novaehollandiae, and brown goshawk, A. fasciatus, are relatively similar in size. The diets of the two goshawks were studied in an area of sympatry, at Abergowrie State Forest, Queensland, in the wet tropics, during the breeding season. The diet of the brown goshawk contained more birds than did that of the grey goshawk, which preyed more on medium-sized mammals and reptiles. The proportion of insects in the diet was similar in the two species. Grey goshawks preferred terrestrial and arboreal prey to the brown goshawks' more aerial prey. The grey goshawk took heavier prey on average and had a slightly more diverse diet. Nevertheless, at 93%, dietary overlap between the goshawks was high. Such high overlap may be possible because of the high diversity and abundance of prey in the tropics, easing interspecific competition.
Developing the formula for state subsidies for health care in Finland
Authors: Häkkinen Unto , Järvelin Jutta
Published: February 2004

Aim: The aim was to generate a research-based proposal for a new subsidy formula for municipal healthcare services in Finland. Methods: Small-area data on potential need variables, supply of and access to services, and age-, sex- and case-mix-standardised service utilisation per capita were used. Utilisation was regressed in order to identify need variables and the cost weights for the selected need variables were subsequently derived using various multilevel models and structural equation methods. Results: The variables selected for the subsidy formula were as follows: age- and sex-standardised mortality (age under 65 years) and income for outpatient primary health services; age- and sex-standardised mortality (all ages) and index of overcrowded housing for elderly care and long-term inpatient care; index of disability pensions for those aged 15 - 55 years and migration for specialised non-psychiatric care; and index of living alone and income for psychiatric care. Conclusion: Decisions on the amount of state subsidies can be divided into three stages, of which the first two are mainly political and the third is based on the results of this study.
The importance of a minimum age law for the possibility of purchase of tobacco by adolescents: a study based on Swedish experiences
Authors: Sundh Mona , Hagquist Curt
Published: February 2004

Aims: The purpose of the study is partly to compare the possibility of adolescents purchasing tobacco before and after the introduction of the minimum age law of 18 years, respectively, and partly to examine the factors that characterize the situations in which adolescents may or may not purchase tobacco, respectively. Methods: Under controlled conditions, adolescents of varying ages carried out test purchases of tobacco. A total of 1,500 attempted purchases were made with the help of 24 adolescents in three regions of Sweden. In 1996, the year before a minimum-age law of 18 for tobacco purchases went into effect, 750 attempted purchases were made, followed by 750 attempted purchases in 1999. Results: In 1996, 91% of the attempted purchases of tobacco were successful. In 1999, the corresponding proportion was 82%. The attempted purchases in 1996 and 1999 show a very strong relationship between whether an age check was made and the result of the attempted purchase. Conclusions: The study shows that the introduction of a minimum-age law apparently has had a certain effect on the possibility of adolescent purchasing tobacco but that there are obvious shortcomings in the enforcement of the minimum age. The most apparent shortcoming concerns the lack of age controls. This article discusses measures for strengthening age controls in the sale of tobacco to adolescents.
Block of vesicular stomatitis virus endocytic and exocytic pathways by 1-cinnamoyl-3,11-dihydroxymeliacarpin, a tetranortriterpenoid of natural origin
Authors: Barquero Andrea A. , Alché Laura E. , Coto Celia E.
Published: February 2004

Previously, it has been shown that 1-cinnamoyl-3,11-dihydroxymeliacarpin (CDM), a natural compound isolated from leaf extracts ofMelia azedarachL., inhibits the vesicular stomatitis virus (VSV) multiplication cycle when added before or after infection. Here, we have established that the lack of VSV protein synthesis in CDM pre-treated Vero cells is ascribed to the inhibition of an initial step during virus multiplication, although indirect immunofluorescence (IFI) studies confirmed that the binding and uptake of [35S]methionine-labelled VSV was not affected by CDM pre-treatment. Instead, our findings revealed that this compound impedes the uncoating of VSV nucleocapsids in pre-treated Vero cells, since the antiviral action of CDM was partially reversed by inducing VSV direct fusion at the plasma membrane, and VSV M protein fluorescence was confined to the endosomes, even 2 h post-internalization. Furthermore, CDM induced cytoplasmic alkalinization, as shown by acridine orange staining, consistent with the inhibition of virus uncoating. Although VSV proteins are synthesized when CDM is added after infection, IFI studies revealed that G protein was absent from the surface of infected cells and co-localized with a Golgi marker. Therefore, CDM inhibits the transport of G protein to the plasma membrane. Taken together, these findings indicate that CDM exerts its antiviral action on the endocytic and exocytic pathways of VSV by pre- or post-treatment, respectively.