2,012 research outputs found
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
Локальные элиминационные алгоритмы обработки запросов в базах данных
Рассмотрено использование локальных элиминационных алгоритмов (ЛЭА) для обработки запросов в реляционных базах данных. Обсуждаются особенности реализации локального алгоритма, использующего лишь прямую часть.Розглянуто використання локальних елімінаційних алгоритмів (ЛЕА) для обробки запитів в реляційних базах даних. Обговорюються особливості реалізації локального алгоритму, що використовує лише пряму частину.The applying local elimination algorithms (LEA) for processing queries in relational databases is considered. The special features of realization of local algorithm using only a forward part are discussed
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
Distributions and habitats of the two partly allopatric cryptic species of the vulnerable moss <i>Hamatocaulis vernicosus </i>(Bryophyta) in Europe
Chronologisches Verzeichniss aller in der Bibliothek der Gelehrten Estnischen Gesellschaft sich befindenden estnischen Druckschriften
http://tartu.ester.ee/record=b1421509~S1*es
Phosphatidic acid binding proteins display differential binding as a function of membrane curvature stress and chemical properties
Curcumin reduces development of seizurelike events in the hippocampal-entorhinal cortex slice culture model for epileptogenesis
OBJECTIVE Inhibition of the mammalian target of rapamycin (mTOR) pathway could be antiepileptogenic in temporal lobe epilepsy (TLE), possibly via anti-inflammatory actions. We studied effects of the mTOR inhibitor rapamycin and the anti-inflammatory compound curcumin-also reported to inhibit the mTOR pathway-on epileptogenesis and inflammation in an in vitro organotypic hippocampal-entorhinal cortex slice culture model. METHODS Brain slices containing hippocampus and entorhinal cortex were obtained from 6-day-old rat pups and maintained in culture for up to 3 weeks. Rapamycin or curcumin was added to the culture medium from day 2 in vitro onward. Electrophysiological recordings revealed epileptiformlike activity that developed over 3 weeks. RESULTS In week 3, spontaneous seizurelike events (SLEs) could be detected using whole cell recordings from CA1 principal neurons. The percentage of recorded CA1 neurons displaying SLEs was lower in curcumin-treated slice cultures compared to vehicle-treated slices (25.8% vs 72.5%), whereas rapamycin did not reduce SLE occurrence significantly (52%). Western blot for phosphorylated-S6 (pS6) and phosphorylated S6K confirmed that rapamycin inhibited the mTOR pathway, whereas curcumin only lowered pS6 expression at one phosphorylation site. Real-time quantitative polymerase chain reaction results indicated a trend toward lower expression of inflammatory markers IL-1β and IL-6 and transforming growth factor β after 3 weeks of treatment with rapamycin and curcumin compared to vehicle. SIGNIFICANCE Our results show that curcumin suppresses SLEs in the combined hippocampal-entorhinal cortex slice culture model and suggest that its antiepileptogenic effects should be further investigated in experimental models of TLE
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