KM3NeT:a large underwater neutrino telescope in the Mediterranean Sea

High energy neutrinos produced in astrophysical processes will allow for a new way of studying the universe. In order to detect the expected flux of high energy neutrinos from specific astrophysical sources, neutrino telescopes of a scale of a km^3 of water will be needed. A Northern Hemisphere detector is being proposed to be sited in a deep area of the Mediterranean Sea. This detector will provide complimentary sky coverage to the IceCube detector being built at the South Pole. The three neutrino telescope projects in the Mediterranean (ANTARES, NEMO and NESTOR) are partners in an effort to design, and build such a km^3 size neutrino telescope, the KM3NeT. The EU is funding a 3-year Design Study; the status of the Design Study is presented and some technical issues are discussed.Comment: 4 pages, 3 figures, Prepared for the 10th International Conference on Astroparticle and Underground Physics (TAUP 2007), Sendai, Japan, 11-15 Sep 200

Sublethal toxicant effects with dynamic energy budget theory: model formulation

We develop and test a general modeling framework to describe the sublethal effects of pollutants by adding toxicity modules to an established dynamic energy budget (DEB) model. The DEB model describes the rates of energy acquisition and expenditure by individual organisms; the toxicity modules describe how toxicants affect these rates by changing the value of one or more DEB parameters, notably the parameters quantifying the rates of feeding and maintenance. We investigate four toxicity modules that assume: (1) effects on feeding only; (2) effects on maintenance only; (3) effects on feeding and maintenance with similar values for the toxicity parameters; and (4) effects on feeding and maintenance with different values for the toxicity parameters. We test the toxicity modules by fitting each to published data on feeding, respiration, growth and reproduction. Among the pollutants tested are metals (mercury and copper) and various organic compounds (chlorophenols, toluene, polycyclic aromatic hydrocarbons, tetradifon and pyridine); organisms include mussels, oysters, earthworms, water fleas and zebrafish. In most cases, the data sets could be adequately described with any of the toxicity modules, and no single module gave superior fits to all data sets. We therefore propose that for many applications, it is reasonable to use the most general and parameter sparse module, i.e. module 3 that assumes similar effects on feeding and maintenance, as a default. For one example (water fleas), we use parameter estimates to calculate the impact of food availability and toxicant levels on the long term population growth rate

Modes of Growth in Dynamic Systems

Regardless of a system's complexity or scale, its growth can be considered to be a spontaneous thermodynamic response to a local convergence of down-gradient material flows. Here it is shown how growth can be constrained to a few distinct modes that depend on the availability of material and energetic resources. These modes include a law of diminishing returns, logistic behavior and, if resources are expanding very rapidly, super-exponential growth. For a case where a system has a resolved sink as well as a source, growth and decay can be characterized in terms of a slightly modified form of the predator-prey equations commonly employed in ecology, where the perturbation formulation of these equations is equivalent to a damped simple harmonic oscillator. Thus, the framework presented here suggests a common theoretical under-pinning for emergent behaviors in the physical and life sciences. Specific examples are described for phenomena as seemingly dissimilar as the development of rain and the evolution of fish stocks.Comment: 16 pages, 6 figures, including appendi

Critical turbulence revisited: The impact of submesoscale vertical mixing on plankton patchiness

By supplying nutrients to the ocean surface, submesoscale vertical motions can have a strong impact on phytoplankton growth and phytoplankton distributions. To study this impact, we model a phytoplankton population in a baroclinically unstable submesoscale eddy using a phytoplankton model coupled to a three-dimensional hydrodynamic model. In the eddy, strong vertical transports are generated as a consequence of baroclinic instability. The resulting plankton distributions turn out to depend strongly on the light intensity and local vertical transport. To analyze these distributions in detail, we use more idealized coupled hydrodynamic-biological models and we extend the critical turbulence concept to three dimensions

Columnar Molecular Aggregation In The Aqueous Solutions Of Disodium Cromoglycate

Stack, chimneylike, and threadlike assemblies have previously been proposed for the structure of disodium cromoglycate (DSCG) aggregates in aqueous solutions. The results of the synchrotron x-ray scattering investigations reported here reveal the formation of simple columnar assemblies with pi-pi stacking at a separation of 3.4 angstrom between the DSCG molecules. Lateral separation between the assemblies is concentration and temperature dependent, varying from similar to 35 to 42 angstrom in the orientationally ordered nematic (N) phase and from 27 to 32 angstrom in the columnar or middle (M) phase having long range lateral positional order. The assemblies\u27 length depends on concentration and consists of similar to 23 molecules in the N phase, becoming three to ten times larger in the M phase. The scission energy is concentration dependent in the N phase with values similar to 7.19 +/- 0.14 k(B)T (15 wt%), 2.73 +/- 0.4 k(B)T (20 wt%), and 3.05 +/- 0.2 k(B)T (25 wt%). Solutions of all concentrations undergo a spinodal decomposition at temperatures above similar to 40 degrees C, resulting in DSCG-rich regions with the M phase and water-rich regions in the N and isotropic phases

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