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1

Electronic Resource

Variation in the components of relative growth rate in 10 Acacia species from contrasting environments (1998)

Atkin, O. K. ; Schortemeyer, M. ; McFarlane, N. ; [et al.]

Oxford, UK : Blackwell Publishing Ltd

Plant, cell & environment 21 (1998), S. 0

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ISSN: 1365-3040

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: In this study we assessed the inherent relative growth rate (RGR) under controlled environment conditions of 10 contrasting Acacia species from semi-arid and mesic environments. For several of the species, compound pinnate leaves produced early in the seedling stage, were gradually replaced by phyllodes (expanded petioles that form simple lamina). Other species either did not form phyllodes, or only did so to a minor degree by the end of the study. Phyllode production was dominant in the four slow-growing Acacia species from semi-arid environments (A. aneura, A. colei, A. coriacea and A. tetragonophylla), with leaf production being exclusive or dominant in five (A. dealbata, A. implexa, A. mearnsii, A. melanoxylon and A. irrorata) of the six faster-growing species from mesic environments. The exception was A. saligna which was fast growing but did produce phyllodes. From a carbon economy perspective, slow growth in the semi-arid species was not associated with lower net assimilation rates or less plant mass allocated to foliage. Rather, the primary factor associated with their slow growth was a smaller foliage area per unit foliage mass. This was true for comparisons based on the mean over all harvests or at set plant masses. The production of phyllodes by the semi-arid species substantially reduced foliage area per unit foliage mass, as this was lower for phyllodes than leaves in all species. To assess the impact that phyllode production had on ontogenetic changes in RGR, we modelled the situation where only leaves were formed. This analysis showed that changing from leaves to phyllodes substantially reduced the RGR. There was little difference in plant nitrogen concentration or the ratio of foliage nitrogen to plant nitrogen between the species. This resulted in foliage nitrogen productivity (dry mass gain per unit foliage nitrogen and time) being directly proportional to foliage area per unit foliage mass between species. We concluded that a smaller foliage area per unit foliage mass and phyllode production are the primary factors associated with lower RGR in contrasting Acacia species.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1046/j.1365-3040.1998.00356.x

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2

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A Meissl-modified Vaníček and Kleusberg kernel to reduce the truncation error in gravimetric geoid computations (1998)

Featherstone, W. E. ; Evans, J. D. ; Olliver, J. G.

Springer

Journal of geodesy 72 (1998), S. 154-160

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ISSN: 1432-1394

Keywords: Key words. Gravimetric geoid determination ; Modified kernels ; Truncation error reduction

Source: Springer Online Journal Archives 1860-2000

Topics: Architecture, Civil Engineering, Surveying

Notes: Abstract. A deterministic modification of Stokes's integration kernel is presented which reduces the truncation error when regional gravity data are used in conjunction with a global geopotential model to compute a gravimetric geoid. The modification makes use of a combination of two existing modifications from Vaníček and Kleusberg and Meissl. The former modification applies a root mean square minimisation to the upper bound of the truncation error, whilst the latter causes the Fourier series expansion of the truncation error to coverage to zero more rapidly by setting the kernel to zero at the truncation radius. Green's second identity is used to demonstrate that the truncation error converges to zero faster when a Meissl-type modification is made to the Vaníček and Kleusberg kernel. A special case of this modification is proposed by choosing the degree of modification and integration cap-size such that the Vaníček and Kleusberg kernel passes through zero at the truncation radius.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s001900050157

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3

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Room-Temperature Superstructure of ZrV2O7 (1998)

Evans, J. S. O. ; Hanson, J. C. ; Sleight, A. W.

Copenhagen : International Union of Crystallography (IUCr)

Acta crystallographica 54 (1998), S. 705-713

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ISSN: 1600-5740

Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001

Topics: Chemistry and Pharmacology , Geosciences , Physics

Notes: The structure of ZrV2O7, zirconium pyrovanadate, has been refined from single-crystal synchrotron X-ray data. As with other phases in the AM2O7 family, ZrV2O7 shows a set of strong reflections, which can be explained on the basis of a cubic unit cell with a = 8.765 Å, and a family of much weaker reflections due to a 3 × 3 × 3 superstructure. The superstructure has been refined to RF = 0.036 (a = 26.296 Å, Pa3¯, 6972 reflections) and contains highly regular ZrO6 and VO4 polyhedra. Of the six unique V2O7 groups, two are constrained by symmetry to contain linear V—O—V linkages, while the remaining four are free to bend away from 180°. The structural distortions from the ideal high-symmetry structure to the observed room-temperature structure are described.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1107/S0108768198000962

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4

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Male characteristics, sperm traits, and reproductive success in winter-spawning Celtic Sea Atlantic herring, Clupea harengus (1998)

Evans, J. P. ; Geffen, A. J.

Springer

Marine biology 132 (1998), S. 179-186

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ISSN: 1432-1793

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The relationship between sperm characteristics and reproductive success was examined in male herring, Clupea harengus L. Males were categorised as being first-time or repeat spawners on the basis of their age; they were also grouped according to whether their sperm were immediately active and exhibited forward motion on contact with seawater (FM) or had little or only vibratory motion (VM). Unlike the Pacific herring C. pallasii Valencienes, Atlantic herring sperm is usually motile on contact with seawater. The age, weight and gonadosomatic index (testes mass as a percentage of somatic mass = GSI) were measured and used as characteristics for individual fish. Sperm traits measured were (1) adenosine triphosphate (ATP) concentration, (2) sperm count, (3) duration of sperm motility. Reproductive success for each male was estimated from the fertilisation rate and from the length of larvae at hatching. Fertilisation rates for all fish were generally 〉80%. The ATP concentration of non-activated spermatozoa was negatively correlated with fertilisation rate. Among repeat spawners, fish with higher GSIs produced larvae that were larger at hatching. Although VM sperm fertilised eggs at rates equivalent to fertilisation by FM sperm, the larvae produced by VM sperm were significantly smaller at hatching. Larval length tended to increase in parallel with the duration of sperm motility, but the relationship was not significant in these tests. The results did not indicate any age or size pattern to spawning readiness in male herring. Sperm that are not yet ready to be shed are not fully motile on contact with seawater, but are still capable of fertilising eggs that hatch successfully. There is likely to be a progression of males which come into spawning readiness within a spawning shoal; therefore it is possible that paternal influences would result in a progressive decrease in larval size over the spawning period in winter-spawning Celtic Sea herring.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s002270050384

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5

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Modified No-hair Conjecture and the Limiting Process (1998)

Nandi, K. K. ; Alam, S. M. K. ; Bhattacharjee, B. ; [et al.]

Springer

General relativity and gravitation 30 (1998), S. 877-885

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ISSN: 1572-9532

Keywords: BRANS-DICKE THEORY ; ITS LIMIT IN GENERAL RELATIVITY

Source: Springer Online Journal Archives 1860-2000

Topics: Physics

Notes: Abstract It is argued that the Schwarzschild black hole solution follows as a unique limit of the Brans-Dicke Class I solutions, provided the correct iterated limit is taken. Such a uniqueness is essential for the validity of a recent version of the no-hair conjecture. A non-trivial modification to this version is proposed in order to exclude Brans-Dicke Class IV solutions which appear to represent scalar hair black holes in general.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1026660108938

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6

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Cross-flow ceramic structures produced by plastic processing (1998)

Payne, C. E. A. ; Evans, J. R. G.

Springer

The international journal of advanced manufacturing technology 14 (1998), S. 508-513

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ISSN: 1433-3015

Keywords: Ceramics ; Extrusion ; Film blowing ; Joining

Source: Springer Online Journal Archives 1860-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Notes: Abstract This paper reports part of an attempt to harness the scope and versatility of polymer manufacturing operations and use them in ceramics processing. It describes the preparation of extruded zirconia ridged plates, the film-blowing of zirconia and the solvent welding of stacks of these components to produce cross-flow structures. Assemblies of this type, prepared from a single ceramic, find application in heat exchangers. Assemblies of composite ceramics, when the problems of cofiring of different powders are overcome, provide solid oxide fuel cell structures. The organic vehicle used for these processes was based on polystyrene. The structures were sintered and then examined for the defects which are characteristic of these plastic-forming operations when applied to ceramics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01351396

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7

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Relative timing of tropical storm lifetime maximum intensity and track recurvature (1998)

Evans, J. L. ; McKinley, K.

Springer

Meteorology and atmospheric physics 65 (1998), S. 241-245

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ISSN: 1436-5065

Source: Springer Online Journal Archives 1860-2000

Topics: Geography , Physics

Notes: Summary An intriguing picture is emerging of coupled track and intensity links in tropical cyclones. Since recurvature represents a dramatic track shift, recurving tropical storms are isolated in this study and their time of maximum lifetime intensity is compared to their time of recurvature. Thirty-one percent of all western North Pacific tropical storms and 28% of all such storms in North Atlantic recurve. Seventeen years of track and intensity data for recurving tropical cyclones in these basins are examined here. The overwhelming majority (≈80%) of western North Pacific tropical storms (including typhoons) reach their lifetime maximum intensity prior to recurvature. More than 45% of all recurving storms have coincident recurvature and lifetime maximum intensity, with weaker tropical storms clearly more likely to reach peak intensity at recurvature than strong systems. Inspection of tropical storm intensity and track data for North Atlantic systems reveals few clear patterns. The most robust observation to be made here is that the majority of these systems reach their peak intensity prior to recurvature. Exclusion of landfalling extratropically transforming tropical cyclones from this sample greatly reduces the number of systems, making the significance of any results questionable.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF01030792

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