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Showing papers by "Royal Holloway, University of London published in 1987"


Journal ArticleDOI
TL;DR: Male songbirds produce extremely elaborate songs, which are the acoustic equivalent of the peacock's tail, and when linked to studies of reproductive success in the field, the results suggest that Darwin was right.
Abstract: Male songbirds produce extremely elaborate songs, which are the acoustic equivalent of the peacock's tail. Darwin suggested that they were the result of sexual selection by female choice, but had no evidence to support his theory. New techniques now permit us to test his theory under controlled laboratory conditions. When linked to studies of reproductive success in the field, the results suggest that Darwin was right.

233 citations


Journal ArticleDOI
01 Jun 1987
TL;DR: In this article, it has been shown that the dominant rock type within the Jaraguay and San Borja volcanic fields is a magnesian andesite, with up to 8% MgO at 57% SiO2, low Fe/Mg ratios, and high Na/K ratios, consistent with derivation from a mantle source with fractionated REE patterns.
Abstract: Late Cenozoic volcanism in Baja California records the effects of cessation of subduction at a previously convergent, plate margin. Prior to 12.5 m.y., when subduction along the margin of Baja ceased, the predominant volcanic activity had a calc-alkaline signature, ranging in composition from basalt to rhyolite. Acidic pyroclastic activity was common, and possibly represented the westermost, distal edge of the Sierra Madre Occidental province. After 12.5 m.y., however, the style and composition of the magmatic products changed dramatically. The dominant rock type within the Jaraguay and San Borja volcanic fields is a magnesian andesite, with up to 8% MgO at 57% SiO2, low Fe/Mg ratios, and high Na/K ratios. These rocks have unusual trace-element characteristics, with high abundances of Sr (up to 3000 ppm), low contents of Rb; K/Rb ratios are very high (usually over 1000, and up to 2500), and Rb/Sr ratios are low (less than 0.01). Furthermore, Lan/Ybn ratios are high, consistent with derivation from a mantle source with fractionated REE patterns. 87Sr/86Sr ratios are less than 0.7048, and usually less than 0.7040, whereas the pre-12.5 m.y. lavas have 87Sr/86Sr ratios between 0.7038 and 0.7063. We have previously termed these rocks bajaites, in order to distinguish them from other magnesian andesites. Bajaites also occur in southernmost Chile and the Aleutian Islands, areas which also have histories of attempted or successful ridge subduction. It is proposed that the bajaite series is produced during the unusual physico-chemical conditions operating during the subduction of young oceanic lithosphere, or subduction of a spreading centre. During normal subduction, the oceanic crust dehydrates, releasing volatiles (water, Rb and other large-ion lithophile elements) into the overlying wedge. Subduction of younger crust will result in a progressive decrease, and eventual cessation of the transfer of volatiles when subduction stops. Thermal rebound of the mantle may cause the slab to melt, perhaps under eclogitestable conditions. The resulting melt will be heavy-REE-depleted, perhaps dacitic, but will otherwise inherit MORB-like Rb/Sr and K/Rb ratios. The ascending melt will react with the mantle to form the source of the bajaitic rocks. Furthermore, any amphibole in the mantle, stabilised during the higher PH2O conditions of earlier subduction, will break down and contribute a high-K/Rb ratio component. The implications of this study are that firstly, the subducted slab does not contribute a highly fractionated REE component in most modern arcs (i.e. the slab does not melt); secondly, Rb has a very short residence time in the mantle, and its abundance in arc rocks is a direct reflection of the input from the dehydrating slab; and thirdly, bajaitelike rocks may provide recognition of attempted or successful ridge subduction in the geologic past.

225 citations


Journal ArticleDOI
TL;DR: In this article, a physically deterministic model of suspended sediment transport in desert streams is presented, and the implications for soil erosion and reservoir siltation are discussed, and sediment is traced from its source to its various sinks within the drainage basin.
Abstract: Hydrological process in arid zones differs substantially from that in better documented humid environments. The ponding point for infiltration is reached within 10 mins of first rain and overland flow forms the major component of basin runoff. Drainage densities are high, approaching 100 km.km−2, maximising the opportunity for both water and eroded soil to reach the channel network. The typical flood bore is not as abrupt as the mythology of desert streams would suggest. Nevertheless, the time of rise of the flood hydrograph is usually between 4 and 16 mins, giving credance to the notion of ‘flash flood’. Measured flows remain subcritical in the main, though Froude number exceeds unity for short periods around peak discharge. Flow is exceedingly turbulent, with Reynolds number > 105 even for much of the recession limb. As a result, suspended sediment concentrations by size grade are shown to be hydraulically controlled. However, the high degree of turbulence and wide availability of sediment from hillslope and channel sources also means that the mean size of the suspended load varies systematically with flow parameters. In this respect, ephemeral streams differ from perennial counterparts in humid environments where no clear-cut relationships exist. There is greater prospect of deriving a physically deterministic model of suspended sediment transport in desert streams. Implications for soil erosion and reservoir siltation are discussed, and sediment is traced from its source to its various sinks within the drainage basin.

113 citations


Journal ArticleDOI

104 citations


Journal ArticleDOI
TL;DR: This paper introduces the class of distance-regularised graphs, a natural common generalisation, that fall into a family of bipartite graphs called distance-biregular and is able to extend much of the basic theory ofdistance-regular graphs to the authors' wider class of graphs.

61 citations


Journal ArticleDOI
TL;DR: An effective but simply implemented strategy is devised which achieves speedup factors of up to ∼25 with real images and is highly robust against shape defects and partial occlusions, and in addition robustness is easily monitored in practical situations.

52 citations


Journal ArticleDOI
TL;DR: The data indicate a strong conservation of VIP during evolution and permit identification of residues crucial for bioactivity.

50 citations


Journal ArticleDOI
TL;DR: An abundance of scorpion cuticles from Westphalian (Upper Carboniferous) coals of Yorkshire is described, and other records of arthropod cuticles in coals are reviewed as mentioned in this paper.
Abstract: An abundance of scorpion cuticles from Westphalian (Upper Carboniferous) coals of Yorkshire is described, and other records of arthropod cuticles in coals are reviewed. The absence of cuticles assignable to arthropod groups other than scorpions is thought to be due to preferential preservation of the unique exocuticle of scorpions; it alone is preserved and appears to retain an organic nature. The cuticle is recovered from all the lithotypes of humic bituminous coals although it is most common in coals rich in inertinite macerals. From the present study it is uncertain whether the scorpions were aquatic or terrestrial. The recognition of arthropod cuticle as a coal maceral could aid environmental interpretations. The abundance of arthropod cuticle in the coals studied indicates its potential use in correlation and in determining the thermal maturity of sediments.

37 citations





Journal ArticleDOI
TL;DR: It is found that the Hough transform is not a simple matched filter and that it has sub-optimal signal detection capability; however, sensitivity is improved by gradient weighting of points in parameter space, when it becomes proportional to image contrast.

Journal ArticleDOI
09 Apr 1987-Nature
TL;DR: This article reported that shells of the marine bivalve mollusc Arctica islandica, collected near King Edward, Scotland, yield isoleucine epimerization D/L ratios only slightly higher than ratios in late-glacial specimens of the same taxon collected from nearby sites.
Abstract: We report here that shells of the marine bivalve mollusc Arctica islandica, collected near King Edward, Scotland, yield isoleucine epimerization D/L ratios only slightly higher than ratios in late-glacial specimens of the same taxon collected from nearby sites. We have determined the ages of two of the King Edward shells by tandem-accelerator mass spectrometry (TAMS) radiocarbon dating to be >40kyr. From the difference in D/L ratios, we calculate the average temperature depression during the last glaciation to have been ≥9 °C below Holocene temperatures.


Journal ArticleDOI
TL;DR: It appears that certain well known masks are relatively inaccurate and anisotropic; new 3 × 3 and 5 × 5 masks are designed which are optimal in these respects.

Journal ArticleDOI
TL;DR: In this paper, over 200 sherds of samian and colour-coated pottery of late 2nd or early 3rd century date have been analysed by inductively coupled plasma (ICP) emission spectrometry.

Journal ArticleDOI
TL;DR: A double blind controlled trial was carried out to measure the efficacy of Sudocrem, compared with zinc cream BP, in the treatment and prevention of incontinence-associated dermatitis in an elderly inpatient population.
Abstract: A double blind controlled trial was carried out to measure the efficacy of Sudocrem, compared with zinc cream BP, in the treatment and prevention of incontinence-associated dermatitis in an elderly inpatient population. Three objective measures of skin condition were used to assess efficacy. Sudocrem was shown to be superior to zinc cream BP in the treatment of dermatitis, with no significant difference shown in terms of prophylaxis. The objective measures of skin health seemed to be a promising advance on earlier, subjective methods, and their further development is recommended. There was some indication that the normal skin of an incontinent patient does not deteriorate when managed with Sudocrem or zinc cream.

Journal ArticleDOI
TL;DR: It is found that noise affects estimation of edge orientation in a complex way, but this is simplified for those ‘circular’ operators which act in a strictly vectorial manner, so the distribution of edge orientations is closely gaussian for gaussian image noise.

Journal ArticleDOI
TL;DR: The Caledonian granites of the British Isles have NH + 4 contents in the range of 0-167 parts per million High contents (>60 ppm) are confined to muscovite-rich granites, occurring principally in a restricted area, namely SE Ireland and the Isle of Man as mentioned in this paper.
Abstract: The Caledonian granites of the British Isles have NH + 4 contents in the range of 0–167 parts per million High contents (>60 ppm) are confined to muscovite-rich granites, occurring principally in a restricted area, namely SE Ireland and the Isle of Man Their magmas are inferred to have formed by the partial melting of a sedimentary protolith rich in organic matter There is no apparent correlation between NH + 4 content and initial 87 Sr/ 86 Sr ratios

Journal ArticleDOI
TL;DR: In this paper, the effects of 16 O → 18 O substitution on the vibrational frequencies of N, N -dimethylformamide have been studied at the 3-21G level.

Journal ArticleDOI
TL;DR: In this article, an algorithm is presented for the construction of efficient neighbor designs for use in field variety trials, based on a two-stage procedure whereby a desirable a-array is obtained first, and then indexed to produce a neighbour array.
Abstract: SUMMARY An algorithm is presented for the construction of efficient neighbour designs for use in field variety trials. The method is based on a two-stage procedure whereby a desirable a-array is obtained first, and then indexed to produce a neighbour array. Three schemes for allocating weights to plots within a block are compared.

Journal ArticleDOI
TL;DR: ADAMO is a data management system for defining data and manipulating them from FORTRAN programs that combines a form of the Entity-Relationship model and the data flow diagrams of structured analysis to provide a system suited to algorithmic work.

Journal ArticleDOI
TL;DR: The classical and quantum-mechanical free energies of crystalline argon were determined at two state points by classical and path integral Monte Carlo methods as discussed by the authors, and the quantum corrections to the free energy, energy and pressure so obtained are compared with corrections based on the harmonic approximation and the first-order term in the Wigner-Kirkwood expansion.


Journal ArticleDOI
TL;DR: Findings are in accord with the idea that the tachykinin family is represented by at least two of its members at the prevertebrate stage of evolution.

Journal ArticleDOI
TL;DR: In this paper, a reflection survey across part of the southern North Sea has revealed SW-dipping bands of reflection segments in the midcrust under the edge of the London Platform.
Abstract: Summary. A reflection survey across part of the southern North Sea has revealed SW-dipping bands of reflection segments in the midcrust under the edge of the London Platform. The upper limit of each group of reflection segments has been contoured in TWT to give a three dimensional impression of the shape of the features. The shape, position and orientation of these groups, together with the reflection character within each group, suggest that they represent large-scale extensional, probably dilatant shear zones. It is proposed that they developed at the edge of the North Sea Basin due to relative movement between an undeformed brittle upper crust and a more ductile lower crust which has been stretched towards the basin to the NE. The shears are thus caused by heterogeneous crustal stretching.

Journal ArticleDOI
TL;DR: Analysis shows that the cause of the problem is inappropriate parametrisation of straight edges and it is found that this difficulty can be rectified, albeit with additional computational effort.

Journal ArticleDOI
TL;DR: In this article, a measurement of the lifetime of the Λc baryon photoproduced coherently off a Germanium-Silicon target is presented and a signal ofΛc→ΔK*→pKπππ0 has been observed and two different decay diagrams for this process are compared.
Abstract: A measurement of the lifetime of theΛc baryon photoproduced coherently off a Germanium-Silicon target is presented. A signal ofΛc→ΔK*→pKππ0 has been observed and the two different decay diagrams for this process are compared. A sample of 9Λc decays gives a lifetime of 1.1−0.4+0.810−13 s.

Journal ArticleDOI
TL;DR: The passing of the Wildlife and Countryside Act 1981 is identified as a turning point and major catalyst in developing new and positive attitudes, especially towards bats.
Abstract: This century has seen major changes in the composition of the British mammal fauna and the abundance of many species, but attitudes towards mammals have changed significantly only relatively recently. The influence of the Mammal Society, popular books, conservation campaigns, radio and television are considered. The passing of the Wildlife and Countryside Act 1981 is identified as a turning point and major catalyst in developing new and positive attitudes, especially towards bats. Attitudes of an essentially urban public towards animals are increasingly unrelated to questions of economic utility and are becoming more paternalistic and protective. They also foster popular campaigns to ban blood sports which need careful appraisal because saving individuals of some common species may lead to loss of whole populations of others as a result of habitat changes.

Journal ArticleDOI
TL;DR: The single most effective method for solubilizing the carotenogenic enzymes was by treatment with 1% Tween 40 for 1 hr at 4°, and the amounts of acyl lipids removed from the membranes were different with each detergent tested.