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Latest papers from The Royal Society`s Journals

September 18, 2002

Please find below the summaries of papers in Proceedings A and B that are due to be published this week on FirstCite, the Royal Society`s new rapid online publication service. Passwords for this site can be supplied to bona fide media on request.

PROCEEDINGS B (Biological sciences)
http://www.catchword.com/rsl/09628452/previews/contp1-1.htm

Biting cleaner fish use altruism to deceive image-scoring client reef fish by Dr R Bshary
The biblical motto 'give and you shall be given' is currently a hot topic in evolutionary biology. In humans, helping increases the probability of being helped by observers, due to a gain in 'image' or 'prestige'. In the present article, I provide observational evidence that indirect benefits of altruism are not restricted to humans. Cleaner fish gain from cooperation with current clients by attracting observing potential client reef fish. But image scoring clients may sometimes be deceived. Cheating cleaners (that eat mucus rather than
ectoparasites) provide small clients with altruistic 'massages' to attract larger victims: 'give and you shall bite'.
Contact: Dr Redouan Bshary, Department of Zoology, University of Cambridge, Downing Street, CAMBRIDGE, CB2 3EJ


Responses of butterflies to twentieth century climate warming: implications for future ranges by Dr JK Hill, Dr CD Thomas, Dr R Fox, Dr Mark G Telfer, Dr SG Willis, Dr J Asher and Dr B Huntley
During 20th-century climate warming, most British butterflies have failed to shift their distributions northwards due to a lack of suitable habitat to colonise. However, northern species have shifted to higher elevations, consistent with a climate explanation. We use climate models to predict potential future butterfly distributions at the end of the 21st century. Assuming species keep perfect track of climate, we predict that species` range sizes would stay about the same. However, more realistic estimates suggest 5-77% declines in range size in the future because most species fail to track climate and fail to expand northwards due to loss of habitat.
Contact: Dr Jane Hill, Department of Biology, University of York, PO Box 373, YORK, YO10 5YW


The structure of reef fish metapopulations: modelling larval dispersal and retention patterns by Dr MK James, Mr PR Armsworth, Dr LB Mason and Dr L Bode
Numerous coastal marine species begin life as minute larvae that disperse for weeks in the ocean before arriving and settling in juvenile habitats. Understanding where larvae go during this open water stage remains one of the most vexing problems in marine ecology. Using extensive computer simulations, the authors have predicted dispersal patterns for reef fish larvae around the complex structures of the Great Barrier Reef, Australia. The modelled dispersal patterns are extremely intricate and variable in both space and time. Based on their predictions, the authors have identified particular spawning habitats that appear critical for sustaining reef fish populations over regional scales.
Contact: Dr Maurice James, School of Engineering, James Cook University, Townsville, Queensland 4811, AUSTRALIA


Host recombination is dependent on the degree of parasitism by Dr JPM Camacho, Dr M Bakkali, Dr JM Corral, Dr J Cabrero, Dr MD Lopez-Leon, Dr I Aranda, Dr Angel Martin-Alganza and Dr F Perfectti
The hypothesis of inducible recombination states that B chromosomes (genome parasites that prosper in natural populations of many living beings) elicit an increase in host chiasma frequency that is favoured by natural selection because it increases the proportion of recombinant progeny, some of which could be resistant to both B-chromosome effects and B accumulation in the germ line. We have found a clear parallelism between host recombination and the evolutionary status of a B chromosome - host system (the grasshopper Eyprepocnemis plorans and its B chromosomes). Our analysis provides an explicit evidence for Inducible Recombination and a strong support for the Red Queen Hypothesis.
Contact: Dr Francisco Perfectti, Departemento de Genetica, Universidad de Granada, E-18071, Granada, SPAIN


Strong influences of larval diet history on subsequent post-settlement growth in the freshwater mollusc Dreisena polymorpha by Mr A Wacker and Dr E Von Elert
Invasion of zebra mussels (Dreissena polymorpha) has caused substantial ecological problems in the Great Lakes in North America. Notwithstanding the view that metamorphosis is regarded as a new start, we observed variation in size and growth of newly settled mussels from the field. Since this variation might be caused by the food of the free swimming larvae in the field, we raised zebra mussel larvae under controlled food regimes. Episodes of low food quantity or quality during larval life reduced size and growth of mussels after metamorphosis. Therefore metamorphosis is not a new beginning for this mussel. The competitive strength of D. polymorpha obviously is affected by the larval food conditions too a greater extent than previously assumed.
Contact: Mr Alexander Wacker, Limnological Institute, University Konstanz, 78434 Konstanz, Germany


PROCEEDINGS A (Mathematical, Physical & Engineering Sciences) http://www.catchword.com/rsl/13645021/previews/contp1-1.htm

Parametrically driven surface waves in surfactant-covered liquids by Dr S Kumar and Dr OK Matar
Everyone knows that when you take an open container of liquid and shake it up and down, waves will form on the liquid surface. We have developed a theory that allows one to calculate the critical shaking magnitude required to excite these waves when surfactants (molecules that lower the surface tension) are adsorbed at the liquid surface. We find that the critical shaking magnitude clearly depends on the spatial distribution of the surfactant. The results of this study will be useful in the development of technologies such as ultrasonic atomization and materials processing in outer space.
Contact: Dr Satish Kumar, Chemical Engineering and Materials Science, University of Minnesota, 151 Amundson Hall, 421 Washington Avenue SE, MINNEAPOLIS, MN 55455-0132, USA


Elastic imperfection sensitivity of hexagonally packed circular-cell honeycombs by Dr J Chung and Professor AM Waas
Cellular solids are finding increasing use in many facets of structural engineering. They are heavily used in sandwich construction. We have provided results for a class of such structures to show which of the their mechanical properties are most affected by unintended imperfections during the process of manufacturing. We have shown that some of these imperfections can induce large changes to the elastic stiffnesses and in the paper we provide expressions to quantify the imperfection sensitivity. The results we have presented
also show that geometric imperfections affect the overall symmetry in mechanical properties that are found with perfectly periodic celluar systems.
Contact: Professor Anthony Waas, Department of Aerospace Engineering, University of Michigan, Francois-Xavier Bagnoud Building 3044, 1320 Beal Street, ANN ARBOR, MI 48109-2140, USA


On the inifinitude of non-zero eigenvalues of the single-electron density matrix for atoms and molecules by Professor G Friesecke
We resolve a classical question in quantum mechanics, concerning the relationship between the "exact`` quantum mechanical description of an atom or molecule and simpler but more intuitive descriptions customary in chemistry. The latter are picturing the electrons as statistically independent of each other, or at most as finite superpositions of statistically independent states. The new result is that this picture is incompatible with the ``exact`` description introduced by Schrodinger, Heisenberg and Dirac in the 1920s. As soon as more than one electron is present, an infinite superposition of statistically independent states is needed. This is yet another illustration of the counterintuitive complexities of the quantum world.
Contact: Professor Gero Friesecke, Mathematics Institute, University of Warwick, COVENTRY, CV4 7AL


The size effect in foams and its theoretical and numerical investigation by Professor S Diebels and
Dr H Steeb
The mechanical behaviour of foams may be described on a microscopic scale and on a macroscopic scale. The microscopic description is based on beam models whereas the macroscopic description makes use of a Cosserat continuum model. This extended continuum model is motivated by the rotations and by the moments which are observed in the micromechanical beam model. In general, the classical continuum mechanical approach cannot describe the material behaviour of foams under different load cases (eg. compression or shear) with only one set of parameters. In the present study it is found that the size effect is the reason for this discrepancy, ie the ratio of the average pore size to the dimensions of the whole specimen governs the experimentally observed stiffness. Both presented approaches, namely the beam model and the Cosserat model respectively, allow for the size effect: The rotations of the nodes between beam elements localise within small bands of width of about one or two cell diameters independent of the overall size of the sample. This localisation is also observed in the Cosserat continuum model and depends on the choice of the internal length, an additional material parameter of the model. Finally, the insight into the physical processes given by the micromechanical model gives an interpretation of the additional parameters of the Cosserat model.
Contact: Professor Stefan Diebels, Lehrstuhl fuer Technische Mechanik, Universitaet des Saarlandes, Geb 22,
Postfach 15 11 50, SAARBRUECKEN, 66041, GERMANY

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