2,081 research outputs found

    Laboratory experiments reveal intrinsic self-sustained oscillations in ocean relevant rotating fluid flows

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    Several ocean Western Boundary Currents (WBCs) encounter a lateral gap along their path. Examples are the Kuroshio Current penetrating into the South China Sea through the Luzon Strait and the Gulf of Mexico Loop Current leaping from the Yucatan peninsula to Florida as part of the Gulf Stream system. Here, we present results on WBC relevant flows, generated in the world’s largest rotating platform, where the Earth’s sphericity necessary to support WBCs is realized by an equivalent topographic effect. The fluid is put in motion by a pump system, which produces a current that is stationary far from the gap. When the jet reaches the gap entrance, time-dependent patterns with complex spatial structures appear, with the jet leaking, leaping or looping through the gap. The occurrence of these intrinsic self-sustained periodic or aperiodic oscillations depending on current intensity is well known in nonlinear dynamical systems theory and occurs in many real systems. It has been observed here for the first time in real rotating fluid flows and is thought to be highly relevant to explain low-frequency variability in ocean WBCs

    Contributi per una flora vascolare di Toscana. VIII (440-506)

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    New localities and/or confirmations concerning 67 specific and subspecific plant taxa of Tuscan vascular flora, belonging to 59 genera and 37 families are presented: Alisma (Alismataceae), Amaranthus (Amaranthaceae), Leucojum, Sternbergia, Tristagma (Amaryllidaceae), Aloe (Asphodelaceae), Erigeron, Galinsoga, Hieracium, Rhagadiolus, Silybum, Soliva, Taraxacum (Asteraceae), Impatiens (Balsaminaceae), Berberis (Berberidaceae), Cardamine (Brassicaceae), Opuntia (Cactaceae), Cephalaria, Sixalix, Succisa (Caprifoliaceae), Silene (Caryophyllaceae), Convolvulus, Ipomoea (Convolvulaceae), Aeonium (Crassulaceae), Scirpus (Cyperaceae), Equisetum (Equisetaceae), Euphorbia (Euphorbiaceae), Astragalus, Trifolium (Fabaceae), Quercus (Fagaceae), Crocus (Iridaceae), Juncus (Juncaceae), Utricularia (Lentibulariaceae), Peplis (Lythraceae), Maclura (Moraceae), Nymphaea (Nymphaeaceae), Oenothera (Onagraceae), Anacamptis, Orchis (Orchidaceae), Orobanche (Orobanchaceae), Callitriche, Veronica (Plantaginaceae), Alopecurus, Eleusine, Glyceria, Phleum (Poaceae), Persicaria, Polygonum (Polygonaceae), Groenlandia (Potamogetonaceae), Clematis, Pulsatilla, Ranunculus (Ranunculaceae), Rhamnus (Rhamnaceae), Fragaria, Potentilla, Pyracantha (Rosaceae), Galium (Rubiaceae), Sparganium (Typhaceae), Vitis (Vitaceae). In the end, the conservation status of the units and eventual protection of the cited biotopes are discussed

    Contributi per una flora vascolare di Toscana. VIII (440-506) [Contributions for a vascular flora of Tuscany. VIII (440-506)]

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    Contributions for a vascular flora of Tuscany. VIII (440-506). New localities and/or confirmations concerning 67 specific and subspecific plant taxa of Tuscan vascular flora, belonging to 59 genera and 37 families are presented: Alisma (Alismataceae), Amaranthus (Amaranthaceae), Leucojum, Sternbergia, Tristagma (Amaryllidaceae), Aloe (Asphodelaceae), Erigeron, Galinsoga, Hieracium, Rhagadiolus, Silybum, Soliva, Taraxacum (Asteraceae), Impatiens (Balsaminaceae), Berberis (Berberidaceae), Cardamine (Brassicaceae), Opuntia (Cactaceae), Cephalaria, Sixalix, Succisa (Caprifoliaceae), Silene (Caryophyllaceae), Convolvulus, Ipomoea (Convolvulaceae), Aeonium (Crassulaceae), Scirpus (Cyperaceae), Equisetum (Equisetaceae), Euphorbia (Euphorbiaceae), Astragalus, Trifolium (Fabaceae), Quercus (Fagaceae), Crocus (Iridaceae), Juncus (Juncaceae), Utricularia (Lentibulariaceae), Peplis (Lythraceae), Maclura (Moraceae), Nymphaea (Nymphaeaceae), Oenothera (Onagraceae), Anacamptis, Orchis (Orchidaceae), Orobanche (Orobanchaceae), Callitriche, Veronica (Plantaginaceae), Alopecurus, Eleusine, Glyceria, Phleum (Poaceae), Persicaria, Polygonum (Polygonaceae), Groenlandia (Potamogetonaceae), Clematis, Pulsatilla, Ranunculus (Ranunculaceae), Rhamnus (Rhamnaceae), Fragaria, Potentilla, Pyracantha (Rosaceae), Galium (Rubiaceae), Sparganium (Typhaceae), Vitis (Vitaceae). In the end, the conservation status of the units and eventual protection of the cited biotopes are discussed

    Notulae to the Italian alien vascular flora: 1

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    In this contribution, new data concerning the Italian distribution of alien vascular flora are presented. It includes new records, exclusions, and confirmations for Italy or for Italian administrative regions for taxa in the genera Agave, Arctotheca, Berberis, Bidens, Cardamine, Catalpa, Cordyline, Cotoneaster, Dichondra, Elaeagnus, Eragrostis, Impatiens, Iris, Koelreuteria, Lamiastrum, Lantana, Ligustrum, Limnophila, Lonicera, Lycianthes, Maclura, Mazus, Paspalum, Pelargonium, Phyllanthus, Pyracantha, Ruellia, Sorghum, Symphyotrichum, Triticum, Tulbaghia and Youngia
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