2,296 research outputs found

    On the identity and systematic placement of Onthophagus viriditinctus Reitter, 1892 (Coleoptera: Scarabaeidae: Scarabaeinae: Onthophagini)

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    A re-description and new records of Onthophagus viriditinctus Reitter, 1892 (Coleoptera: Scarabaeidae: Scarabaeinae: Onthophagini), an uncommon species from Iran, are provided. The taxonomic position and some nomenclatural problems are discussed. The placement in the subgenus Exonthophagus Kabakov, 2006 is proposed. Images of the male, female, aedeagus and drawings of lamella copulatrix of Onthophagus viriditinctus and Onthophagus haroldi Ballion, 1871, the only other species included in the subgenus, are supplied. A key for distinguishing the two species is provided

    An efficient segmentation method to price American Put options

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    A segmentation strategy to price different groups of American standard Put options with different methods is presented and discussed. The method, which exploits the properties of the odd waves of the BI adjusted evaluations introduced by Gaudenzi and Pressacco, proves to be very efficient in particular, to price critical in the money options.American put plain vanilla options; tree evaluation methods; American quality; segmentation

    Bilateral symmetry and modified Pascal triangles in Parsimonious games

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    We discuss the prominent role played by bilateral symmetry and modified Pascal triangles in self twin games, a subset of constant sum homogeneous weighted majority games. We show that bilateral symmetry of the free representations unequivocally identifies and characterizes this class of games and that modified Pascal triangles describe their cardinality for combinations of m and k, respectively linked through linear transforms to the key parameters n, number of players and h, number of types in the game. Besides, we derive the whole set of self twin games in the form of a genealogical tree obtained through a simple constructive procedure in which each game of a generation, corresponding to a given value of m, is able to give birth to one child or two children (depending on the parity of m), self twin games of the next generation. The breeding rules are, given the parity of m, invariant through generations and quite simple.Comment: pp. 2

    Taxonomic notes on Onthophagus (Palaeonthophagus) lemuroides d’Orbigny, 1898 and O. (P.) fortigibber Reitter, 1909 (Coleoptera: Scarabaeidae: Scarabaeinae: Onthophagini)

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    The taxonomic position of Onthophagus (Palaeonthophagus) lemuroides d’Orbigny, 1898 and Onthophagus (Palaeonthophagus) fortigibber Reitter, 1909 is discussed (Coleoptera: Scarabaeidae: Scarabaeinae: Onthophagini). A key to the species is given. Photos of type specimens of the two taxa and significant chromatic varieties, and drawings of aedeagi are presented

    Twin relationships in Parsimonious Games: some results

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    In a vintage paper concerning Parsimonious games, a subset of constant sum homogeneous weighted majority games, Isbell introduced a twin relationship based on transposition properties of the incidence matrices upon minimal winning coalitions of such games. A careful investigation of such properties allowed the discovery of some results on twin games presented in this paper. In detail we show that a) twin games have the same minimal winning quota and b) each Parsimonious game admits a unique balanced lottery on minimal winning coalitions, whose probabilities are given by the individual weights of its twin game

    Access to Population-Level Signaling as a Source of Inequality

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    We identify and explore differential access to population-level signaling (also known as information design) as a source of unequal access to opportunity. A population-level signaler has potentially noisy observations of a binary type for each member of a population and, based on this, produces a signal about each member. A decision-maker infers types from signals and accepts those individuals whose type is high in expectation. We assume the signaler of the disadvantaged population reveals her observations to the decision-maker, whereas the signaler of the advantaged population forms signals strategically. We study the expected utility of the populations as measured by the fraction of accepted members, as well as the false positive rates (FPR) and false negative rates (FNR). We first show the intuitive results that for a fixed environment, the advantaged population has higher expected utility, higher FPR, and lower FNR, than the disadvantaged one (despite having identical population quality), and that more accurate observations improve the expected utility of the advantaged population while harming that of the disadvantaged one. We next explore the introduction of a publicly-observable signal, such as a test score, as a potential intervention. Our main finding is that this natural intervention, intended to reduce the inequality between the populations' utilities, may actually exacerbate it in settings where observations and test scores are noisy

    K-Fibonacci sequences and minimal winning quota in Parsimonious game

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    Parsimonious games are a subset of constant sum homogeneous weighted majority games unequivocally described by their free type representation vector. We show that the minimal winning quota of parsimonious games satisfies a second order, linear, homogeneous, finite difference equation with nonconstant coefficients except for uniform games. We provide the solution of such an equation which may be thought as the generalized version of the polynomial expansion of a proper k-Fibonacci sequence. In addition we show that the minimal winning quota is a symmetric function of the representation vector; exploiting this property it is straightforward to prove that twin Parsimonious games, i.e. a couple of games whose free type representations are each other symmetric, share the same minimal winning quota

    AFM probe for the signatures of Wigner correlations in the conductance of a one-dimensional quantum dot

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    The transport properties of an interacting one-dimensional quantum dot capacitively coupled to an atomic force microscope probe are investigated. The dot is described within a Luttinger liquid framework which captures both Friedel and Wigner oscillations. In the linear regime, we demonstrate that both the conductance peak position and height oscillate as the tip is scanned along the dot. A pronounced beating pattern in the conductance maximum is observed, connected to the oscillations of the electron density. Signatures of the effects induced by a Wigner molecule are clearly identified and their stability against the strength of Coulomb interactions are analyzed. While the oscillations of the peak position due to Wigner get enhanced at strong interactions, the peak height modulations are suppressed as interactions grow. Oscillations due to Friedel, on the other hand, are robust against interaction.Comment: 9 figure

    Probing Wigner correlations in a suspended carbon nanotube

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    The influence of the electron-vibron coupling on the transport properties of a strongly interacting quantum dot built in a suspended carbon nanotube is analyzed. The latter is probed by a charged AFM tip scanned along the axis of the CNT which induces oscillations of the chemical potential and of the linear conductance. These oscillations are due to the competition between finite-size effects and the formation of a Wigner molecule for strong interactions. Such oscillations are shown to be suppressed by the electron-vibron coupling. The suppression is more pronounced in the regime of weak Coulomb interactions, which ensures that probing Wigner correlations in such a system is in principle possible
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