Flow-Performance Relationship and Tournament Behavior in the Mutual Fund Industry

In this paper, we interpret the flow-performance relationship as an incentive scheme implicitly given to mutual fund managers by mutual fund investors. We show that the flow-performance relationship varies not only with economic activity but also across fund attributes. We provide evidence that the degree of convexity of the flow-performance relationship has a positive effect on the magnitude of tournament behavior. Different from the conventional tournament hypothesis, we show that although the convexity of the flow-performance relationship does produce implicit incentives for fund managers to modify risk-taking behavior as a function of their prior performance, whether or not the mid-year losers increase the risk of thei

Analysis of lethal and sublethal impacts of environmental disasters on sperm whales using stochastic modeling

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecotoxicology 26 (2017): 820-830, doi:10.1007/s10646-017-1813-4.Mathematical models are essential for combining data from multiple sources to quantify population endpoints. This is especially true for species, such as marine mammals, for which data on vital rates are difficult to obtain. Since the effects of an environmental disaster are not fixed, we develop time-varying (nonautonomous) matrix population models that account for the eventual recovery of the environment to the pre-disaster state. We use these models to investigate how lethal and sublethal impacts (in the form of reductions in the survival and fecundity, respectively) affect the population’s recovery process. We explore two scenarios of the environmental recovery process and include the effect of demographic stochasticity. Our results provide insights into the relationship between the magnitude of the disaster, the duration of the disaster, and the probability that the population recovers to pre-disaster levels or a biologically relevant threshold level. To illustrate this modeling methodology, we provide an application to a sperm whale population. This application was motivated by the 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico that has impacted a wide variety of species populations including oysters, fish, corals, and whales.This research is part of the Littoral Acoustic Demonstration Center-Gulf Ecological Monitoring and Modeling (LADC-GEMM) consortium project supported by Gulf of Mexico Research Initiative Year 5–7 Consortia Grants (RFP-IV). Hal Caswell also acknowledges support from ERC Advanced Grant 322989

Entomopathogenic Fungi on Hemiberlesia pitysophila

Hemiberlesia pitysophila Takagi is an extremely harmful exotic insect in forest to Pinus species, including Pinus massoniana. Using both morphological taxonomy and molecular phylogenetics, we identified 15 strains of entomogenous fungi, which belong to 9 genera with high diversities. Surprisingly, we found that five strains that were classified as species of Pestalotiopsis, which has been considered plant pathogens and endophytes, were the dominant entomopathogenic fungus of H. pitysophila. Molecular phylogenetic tree established by analyzing sequences of ribosomal DNA internal transcribed spacer showed that entomopathogenic Pestalotiopsis spp. were similar to plant Pestalotiopsis, but not to other pathogens and endophytes of its host plant P. massoniana. We were the first to isolate entomopathogenic Pestalotiopsis spp. from H. pitysophila. Our findings suggest a potential and promising method of H. pitysophila bio-control

Analysis of lethal and sublethal impacts of environmental disasters on sperm whales using stochastic modeling

Mathematical models are essential for combining data from multiple sources to quantify population endpoints. This is especially true for species, such as marine mammals, for which data on vital rates are difficult to obtain. Since the effects of an environmental disaster are not fixed, we develop time-varying (nonautonomous) matrix population models that account for the eventual recovery of the environment to the pre-disaster state. We use these models to investigate how lethal and sublethal impacts (in the form of reductions in the survival and fecundity, respectively) affect the population’s recovery process. We explore two scenarios of the environmental recovery process and include the effect of demographic stochasticity. Our results provide insights into the relationship between the magnitude of the disaster, the duration of the disaster, and the probability that the population recovers to pre-disaster levels or a biologically relevant threshold level. To illustrate this modeling methodology, we provide an application to a sperm whale population. This application was motivated by the 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico that has impacted a wide variety of species populations including oysters, fish, corals, and whales

Some necessary and sufficient conditions for nilpotent nn-Lie superalgebras

summary:The paper studies nilpotent $n$-Lie superalgebras over a field of characteristic zero. More specifically speaking, we prove Engel's theorem for $n$-Lie superalgebras which is a generalization of those for $n$-Lie algebras and Lie superalgebras. In addition, as an application of Engel's theorem, we give some properties of nilpotent $n$-Lie superalgebras and obtain several sufficient conditions for an $n$-Lie superalgebra to be nilpotent by using the notions of the maximal subalgebra, the weak ideal and the Jacobson radical

On the Cohomology and Extensions of n-ary Multiplicative Hom-Nambu-Lie Superalgebras

In this paper, we discuss the representations of n-ary multiplicative Hom-Nambu-Lie superalgebras as a generalization of the notion of representations for n-ary multiplicative Hom-Nambu-Lie algebras. We also give the cohomology of an n-ary multiplicative Hom-Nambu-Lie superalgebra and obtain a relation between extensions of an n-ary multiplicative Hom-Nambu-Lie superalgebra b by an abelian one a and Z1b,a0¯. We also introduce the notion of T∗-extensions of n-ary multiplicative Hom-Nambu-Lie superalgebras and prove that every finite-dimensional nilpotent metric n-ary multiplicative Hom-Nambu-Lie superalgebra over an algebraically closed field of characteristic not 2 in the case α is a surjection is isometric to a suitable T∗-extension

On the Deformations and Derivations of n-Ary Multiplicative Hom-Nambu-Lie Superalgebras

We introduce the relevant concepts of n-ary multiplicative Hom-Nambu-Lie superalgebras and construct three classes of n-ary multiplicative Hom-Nambu-Lie superalgebras. As a generalization of the notion of derivations for n-ary multiplicative Hom-Nambu-Lie algebras, we discuss the derivations of n-ary multiplicative Hom-Nambu-Lie superalgebras. In addition, the theory of one parameter formal deformation of n-ary multiplicative Hom-Nambu-Lie superalgebras is developed by choosing a suitable cohomology