501,745 research outputs found

    Volcanism on the Pacific Ring of Fire: It's Going to Blow Up! (title provided or enhanced by cataloger)

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    In this activity students familiarize themselves with some basic concepts of volcanology and investigate a portion of the Ring of Fire. They then research the answers to questions on the provided worksheet. As a result of this activity students will be able to describe the processes that produce the "Submarine Ring of Fire," explain the factors that contribute to explosive volcanic eruptions, identify at least three benefits that humans derive from volcanism, describe the primary risks posed by volcanic activity in the United States, and identify the volcano within the continental United States that is considered most dangerous. Educational levels: Middle school

    SAMUDRA Report, No. 50, August 2008

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    Report: Rights-based fishing - Flagging rights, realizing responsibilities. Senegal: Artisanal fisheries - A health check. Analysis: Fuel prices - Fishing in times of high prices. Panama: Protected areas - Mother earth, mother sea. Review: Films - A restless, throbbing ballet. Norway: Fuel subsidies - Skimming the cream. India: Coastal Management - Save the coast, save the fishers. Report: Chile Workshop - Common concerns, lasting bonds. Indonesia: Fisheries Legislation - Ring of fire. Report: CBD COP9 - Breaking away from tradition. On Samudra Report At 50 – Supplement. (64 pp.

    Testing for anthropogenic influence on fire regime for a 600-year period in the Jaksha area, Komi Republic, East European Russia

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    In an attempt to quantitatively evaluate the natural versus anthropogenic signal in site fire histories, the statistical relationship between dendrochronologically dated fire events and tree-ring chronologies (deemed to be an independent proxy for climate variation) was analyzed for 14 sites in a 2600-km(2) area of pine-dominated forests in the Komi Republic (East European Russia) over the period from 1424 to 1954. We developed a cumulative measure of statistical fit between two types of fire events (early- and late-season fires) and ring-width chronologies of Scots pine (Pinus sylvestris L.) (total ring- and latewood-width chronologies). For a given site, the statistical fit between fires and tree-ring data tended to decrease with an increasing proportion of unique fire years. Distance from a site to the nearest village (deemed to be a proxy of human impact) explained 50% of the variation in statistical fit between fires and tree-ring data. The fit decreased in the majority of the sites from the earlier (1424-1700) to the later (1700-1960) periods. We interpret this to be a result of increased human impact on the fire regime since 1700 due to intensified colonization of the area

    „Volcker/Vickers Hybrid“?: The Liikanen Report and Justifications For Ring Fencing and Separate Legal Entities

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    Whilst some valid and justified arguments have been put forward in favour of ring fencing, that is, constructing a fire-wall between consumer and investment banks, and that such activities can be achieved without re structuring banks into separate legal entities, the Liikanen Report highlights why there is need for such re structuring. As well as considering the merits of ringfencing and the establishment of separate legal activities and entities, this paper aims to highlight why a suitable model aimed at mitigating risks of contagion can to a large extent, be justified on a cost-benefit analysis basis. Furthermore, the paper ultimately concludes that even though a greater degree of separation of legal entities and activities persist with the model which is referred to as „total separation“, a certain degree of independence between bank activities would also be necessary under ring fencing if its purposes and objectives are to be fulfilled

    Cyclic volcanism at convergent margins: linked to aarth orbital parameters or climate changes?

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    EGU2010-13373 The frequency of volcanic activity varies on a wide rangeof spatial and temporal scales, from <1 yr. periodicities in single volcanic systems to periodicities of 106 yrs. in global volcanism. The causes of these periodicities are poorly understood although the long-term global variations are likely linked to plate-tectonic processes. Here we present evidence for temporal changes in eruption frequencies at an intermediate time scale (104 yrs.) using the Pleistocene to recent records of widespread tephras of sub-Plinian to Plinian, and occasionally co-ignimbrite origin, along the Pacific Ring of Fire, which accounts for about half of the global length of 44,000 km of active subduction. Eruptions at arc volcanoes tend to be highly explosive and the well-preserved tephra records from the ocean floor can be assumed to be representative of how eruption frequencies varied with time. Volcanic activity along the Pacific Ring of Fire evolved through alternating phases of high and low frequency; although there is modulation by local and regional geologic conditions, these variations have a statistically significant periodicity of 43 ka that overlaps with the temporal variation in the obliquity of the Earth’s rotation axis, an orbital parameter that also exerts a strong control on global climate changes. This may suggest that the frequency of volcanic activity is controlled by effects of global climate changes. However, the strongest physical effects of climate change occur at 100 ka periods which are not seen in the volcanic record. We therefore propose that the frequency of volcanic activity is directly influenced by minute changes in the tidal forces induced by the varying obliquity resulting in long-period gravitational disturbances acting on the upper mantle

    Chimeras in Leaky Integrate-and-Fire Neural Networks: Effects of Reflecting Connectivities

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    The effects of nonlocal and reflecting connectivity are investigated in coupled Leaky Integrate-and-Fire (LIF) elements, which assimilate the exchange of electrical signals between neurons. Earlier investigations have demonstrated that non-local and hierarchical network connectivity often induces complex synchronization patterns and chimera states in systems of coupled oscillators. In the LIF system we show that if the elements are non-locally linked with positive diffusive coupling in a ring architecture the system splits into a number of alternating domains. Half of these domains contain elements, whose potential stays near the threshold, while they are interrupted by active domains, where the elements perform regular LIF oscillations. The active domains move around the ring with constant velocity, depending on the system parameters. The idea of introducing reflecting non-local coupling in LIF networks originates from signal exchange between neurons residing in the two hemispheres in the brain. We show evidence that this connectivity induces novel complex spatial and temporal structures: for relatively extensive ranges of parameter values the system splits in two coexisting domains, one domain where all elements stay near-threshold and one where incoherent states develop with multileveled mean phase velocity distribution.Comment: 12 pages, 12 figure
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