Fish and freshwater crayfish in streams in the Cape Naturaliste region and Wilyabrup Brook

No abstract availabl

Satellite-observed vegetation as an indicator of climate variability over southern Africa

The satellite-derived normalised difference vegetation index (NDVI) offers new opportunities to assess the impact of year-to-year climate fluctuations. In this study the NDVI is mapped over southern Africa for the period 1981-1994. Sharp upward and downward trends follow the cycle of summer flood and drought. January to March NDVI values are correlated at +0.82 with harvested maize yield for the North West Province of central South Africa. Departures of late summer NDVI from the historical mean illustrates the distribution and intensity of the influence of the Southern Oscillation, in alternating seasons of vegetative growth and depletion. The first principal component of the NDVI field time series contains a broad signal covering all of Africa south of 15 degrees S, and appears related to the low frequency component of the global El Nino phenomenon

The discovery of plant biodiversity by children through the animated movies: Alice in Wonderland

The discovery of biodiversity in childs occurs through various channels: either through direct contact with the outside world, and indirectly through paintings, games and the media. Since 1937, Walt Disney Animation Studios realized animated movies inspired from novels. The first feature film was \u201cSnow White and the Seven Dwarfs\u201d. Since this, Disney\u2019s studios realized more than 10 dozen movies. The feature that distinguishes these works from a technical point of view is the attention to detail especially for the scene where the action takes place. Animals are often the protagonists of these stories, rarely plants. A good example of the latter is in \u201cAlice in wonderland\u201d, a movie distributed in 1951 that tells the story of the discovery by Alice of an unmusical, fantasy-filled world beyond her imagination populated by odd human and plant and animal characters. The plot of this film is taken from \u201cAlice's Adventures in Wonderland\u201d, an 1865 novel written by Charles Lutwidge Dodgson under the pseudonym Lewis Carroll with several inclusions of the sequel \u201cThrough the Looking-Glass\u201d another novel by the same Lewis Carroll, published in 1871. Both are novels full of symbolism, mathematical allusions and satire and contain the customs of England in the Victorian Age. Alice, in the real and in in her imaginary world, moves within scenarios in which plants are the main background. But it happens in the scene in which Alice is in the flower garden that flowers come alive and become characters of the story. This scene is inspired by the second chapter of the \u201cThrough the Looking- Glass\u201d titled \u201cThe garden of live flowers\u201d. In the novel, Alice comes up a hill along a winding path, that houses a flower garden populated by daisies, a weeping willow, a lily, a rose, a larkspur and a violet. The real work of exaltation of plant biodiversity is made in the film by Walt Disney where in a scene of about 5 minutes more than 20 flowers are presented. In the scene are clearly identifiable: Bellis perennis, Cestrum elegans, Chrysanthemum indicum, Convallaria majalis, Cyclamen persicum, Delphinium sp., Hyancinthoides non-scripta, Ipomoea violacea, Iris germanica, Leucanthemum 7superbum, Leucanthemum vulgare, Lilium candidum, L. davidii, Narcissus incomparabilis, N. pseudonarcissus, Nelumbo nucifera, Ranunculus asiaticus, Rosa indica, Salix babylonica, Syringa vulgaris, Taraxacum sect. Taraxacum, Viola odorata, V. 7wittrockiana and Zinnia sp. It is a real triumph of sounds and colours that leave the spectator delighted. The theme of the plants between knowledge and representation has been the subject of international meetings and scientific contributions. Studies about the representation of plants in pre-Christian (1), during the Middle Ages and in European art of the XIV - XVII have been done (2). In our case the plants drawn in Alice in Wonderland seems to belong more to the plants cultivated in the Americans gardens of during 1950\u2019s, when the film was made, rather than to the English gardens of the Victorian era where the novel is set. Nevertheless these drawings approach children, and the adults accompanying them in the vision, to the biodiversity of flowering plants cultivated. Offering to the spectator a wide representation of plants commonly grown with their shape and colours. Certainly, "Alice in wonderland" is a good example of how even cartoons, such as fairy tales, can play an educational role, as they allow the child to learn while having fun. In particular, this cartoon can be a good teaching tool for knowledge of plant biodiversity. In fact, it can provide many ideas for developing a number of educational activities to be proposed in both the kindergarten and in the primary school, intended to make understand even the youngest children the meaning and the value of plant biodiversity, as well as to know some plants and their growth environments. Therefore, it would be desirable in the future to take into account such aspects, uncommon in animated films for children. In consideration of the now urgent need to fill several gaps of knowledge, widespread in the younger generation (3) in respect of the plants and the environment in general

Disrupted Lipid Metabolism in Multiple Sclerosis: A Role for Liver X Receptors?

Multiple sclerosis (MS) is a chronic neurological disease driven by autoimmune, inflammatory and neurodegenerative processes leading to neuronal demyelination and subsequent degeneration. Systemic lipid metabolism is disturbed in people with MS, and lipid metabolic pathways are crucial to the protective process of remyelination. The lipid-activated transcription factors liver X receptors (LXRs) are important integrators of lipid metabolism and immunity. Consequently, there is a strong interest in targeting these receptors in a number of metabolic and inflammatory diseases, including MS. We have reviewed the evidence for involvement of LXR-driven lipid metabolism in the dysfunction of peripheral and brain-resident immune cells in MS, focusing on human studies, both the relapsing remitting and progressive phases of the disease are discussed. Finally, we discuss the therapeutic potential of modulating the activity of these receptors with existing pharmacological agents and highlight important areas of future research

A scaling theory of 3D spinodal turbulence

A new scaling theory for spinodal decomposition in the inertial hydrodynamic regime is presented. The scaling involves three relevant length scales, the domain size, the Taylor microscale and the Kolmogorov dissipation scale. This allows for the presence of an inertial "energy cascade", familiar from theories of turbulence, and improves on earlier scaling treatments based on a single length: these, it is shown, cannot be reconciled with energy conservation. The new theory reconciles the t^{2/3} scaling of the domain size, predicted by simple scaling, with the physical expectation of a saturating Reynolds number at late times.Comment: 5 pages, no figures, revised version submitted to Phys Rev E Rapp Comm. Minor changes and clarification

Vapour-liquid coexistence in many-body dissipative particle dynamics

Many-body dissipative particle dynamics is constructed to exhibit vapour-liquid coexistence, with a sharp interface, and a vapour phase of vanishingly small density. In this form, the model is an unusual example of a soft-sphere liquid with a potential energy built out of local-density dependent one-particle self energies. The application to fluid mechanics problems involving free surfaces is illustrated by simulation of a pendant drop.Comment: 8 pages, 6 figures, revtex

Diffusive transport of light in two-dimensional granular materials

We study photon diffusion in a two-dimensional random packing of monodisperse disks as a simple model of granular material. We apply ray optics approximation to set up a persistent random walk for the photons. We employ Fresnel's intensity reflectance with its rich dependence on the incidence angle and polarization state of the light. We present an analytic expression for the transport-mean-free path in terms of the refractive indices of grains and host medium, grain radius, and packing fraction. We perform numerical simulations to examine our analytical result.Comment: 9 pages, 3 figure

A Cellular Automata Model with Probability Infection and Spatial Dispersion

In this article, we have proposed an epidemic model by using probability cellular automata theory. The essential mathematical features are analyzed with the help of stability theory. We have given an alternative modelling approach for the spatiotemporal system which is more realistic and satisfactory from the practical point of view. A discrete and spatiotemporal approach are shown by using cellular automata theory. It is interesting to note that both size of the endemic equilibrium and density of the individual increase with the increasing of the neighborhood size and infection rate, but the infections decrease with the increasing of the recovery rate. The stability of the system around the positive interior equilibrium have been shown by using suitable Lyapunov function. Finally experimental data simulation for SARS disease in China and a brief discussion conclude the paper

Use of groundwater lifetime expectancy for the performance assessment of a deep geologic waste repository: 1. Theory, illustrations, and implications

Long-term solutions for the disposal of toxic wastes usually involve isolation of the wastes in a deep subsurface geologic environment. In the case of spent nuclear fuel, if radionuclide leakage occurs from the engineered barrier, the geological medium represents the ultimate barrier that is relied upon to ensure safety. Consequently, an evaluation of radionuclide travel times from a repository to the biosphere is critically important in a performance assessment analysis. In this study, we develop a travel time framework based on the concept of groundwater lifetime expectancy as a safety indicator. Lifetime expectancy characterizes the time that radionuclides will spend in the subsurface after their release from the repository and prior to discharging into the biosphere. The probability density function of lifetime expectancy is computed throughout the host rock by solving the backward-in-time solute transport adjoint equation subject to a properly posed set of boundary conditions. It can then be used to define optimal repository locations. The risk associated with selected sites can be evaluated by simulating an appropriate contaminant release history. The utility of the method is illustrated by means of analytical and numerical examples, which focus on the effect of fracture networks on the uncertainty of evaluated lifetime expectancy.Comment: 11 pages, 8 figures; Water Resources Research, Vol. 44, 200

EQUILIBRIUM CALCULATION IN THE SYSTEM: URANYL NITRATE, NITRIC ACID, WATER, TBP, AND KEROSENE DILUENT USING THE ORACLE DIGITAL COMPUTER

A set of equations was written which allowed the calculation of equilibrium concentrations in the solvent phase of nitric acid and uranyl nitrate, given the initial TBP concentration in the solvent and the aqueous phase concentrations of acid and uranium. An ORACLE subroutine was written based on these equations which will calculate a set of equilibrium values in about 35 milliseconds. The subroutine was incorporated into a short program to calculate equilibrium points. A set of calculated points are presented in graphical form for 5, up to 7 M and uranyl nitrate concentrations up to 0.6 M in the aqueous phase. Since these calculations were based on limited data, it is the purpose of this memo to invite comment on their accuracy. The equations were reworked from a Russian paper by A. M. Rozen and L. P. Khorkhorina, using emperical polynomial fits for some poorly defined parameters, and were based principally on data from J. W. Codding. This project was undertaken to provide a subroutine to calculate equilibria in a general purpose ORACLE program to calculate the performance of multi-stage compound extraction cascades with more than one significant solute. (auth