60 research outputs found

    Risk-Sensitive Resource Defense in a Territorial Reef Fish

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    As coral reefs are home to dense aggregations of a variety of species, aggressive territoriality is often a critical component of individual behavior. Identification and assessment of the risk posed by intruders is crucial to defending a territory, and fishes on coral reefs have been found to attend to body shape, body size, and coloration when responding to intruders. We examined the extent to which dusky damselfish (Stegastes adustus) discriminate among distinct categories of intruders by measuring the distance at which a fish attacks an intruder and the relative intensity and frequency of those attacks. We found that S. adustus discriminated among perceived threats, attacking conspecifics more intensely and more often than egg-predators and herbivores, and showing a trend of attacking those groups more often than invertebrate-feeders, which do not compete with damselfish for resources. Furthermore, territory holders attacked initial-phase wrasses from a farther distance than terminal-phase wrasses, suggesting that they can discriminate among classes of individuals within a species other than their own. Dusky damselfish thus exhibit the ability to make fine distinctions among intruders in a diverse ecosystem

    Re-evaluating syndicalist opposition to the First World War

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    It has been argued that support for the First World War by the important French syndicalist organisation, the ConfĂ©dĂ©ration GĂ©nĂ©rale du Travail (CGT) has tended to obscure the fact that other national syndicalist organisations remained faithful to their professed workers’ internationalism: on this basis syndicalists beyond France, more than any other ideological persuasion within the organised trade union movement in immediate pre-war and wartime Europe, can be seen to have constituted an authentic movement of opposition to the war in their refusal to subordinate class interests to those of the state, to endorse policies of ‘defencism’ of the ‘national interest’ and to abandon the rhetoric of class conflict. This article, which attempts to contribute to a much neglected comparative historiography of the international syndicalist movement, re-evaluates the syndicalist response across a broad geographical field of canvas (embracing France, Italy, Spain, Ireland, Britain and America) to reveal a rather more nuanced, ambiguous and uneven picture. While it highlights the distinctive nature of the syndicalist response compared with other labour movement trends, it also explores the important strategic and tactical limitations involved, including the dilemma of attempting to translate formal syndicalist ideological commitments against the war into practical measures of intervention, and the consequences of the syndicalists’ subordination of the political question of the war to the industrial struggle

    Options and financial futures: valuation and uses/ Dubofsky

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    xx, 699 hal.; 24 cm

    Mutual fund portfolio trading and investor flow

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    I estimate the extent to which mutual fund portfolio trading of securities is triggered by investor flows into and out of the funds, and find that this liquidity-induced portfolio trading activity is smaller than previously estimated by Edelen (1999). I obtain estimates from a much larger and broader sample of funds than Edelen's (1999) sample. Portfolio managers of international funds trade a smaller fraction of investor flow than do those of domestic funds. Index funds invest a larger fraction. A funds' usage of futures contracts does not have a statistically significant effect on how it trades in response to investor flows, but the unpredictability of investor flow weakly affects the trading response to flow.Mutual funds Fund flows

    Volatility Increases Subsequent to NYSE and AMEX Stock Splits.

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    The post-split increase in daily returns volatility is less for AMEX stocks than for NYSE stocks. The exchange trading location is a significant factor in explaining the volatility shift even after stock price and firm size are considered. Furthermore, when measured on a weekly basis, there is no increase in AMEX stocks' returns volatility. These results suggest that measurement errors created by bid-ask spreads and the 1/8 effect, and also one or more of the elements that make the NYSE different from the AMEX, explain why the estimated volatility of daily stock returns increases after the ex split date. Copyright 1991 by American Finance Association.

    Options and financial futures: valuation and uses/ Dubofsky

    No full text
    xx, 699 hal.; 24 cm
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