Las especies amenazadas son indicadoras de los puntos calientes de la regulación trófica en sentido descendente

Se ha considerado la introducción de mesopredadores y herbívoros extranjeros como el principal desencadenante de la extinción de mamíferos australianos. Estudios recientes sugieren que los efectos devastadores de las especies invasoras quedan mitigados por los superpredadores. Por lo tanto, la supervivencia de muchas especies amenazadas puede depender de la presencia y funcionalidad ecológica de los grandes predadores. El superpredador australiano, el dingo (Canis lupus dingo) ha sido muy perseguido por todo el continente, y es extremadamente raro encontrar poblaciones de dingos que no estén sujetas a un control letal. En este estudio pronosticamos que la presencia de especies amenazadas señala los lugares donde las poblaciones de dingos están relativamente intactas, y que su ausencia puede indicar que los dingos son raros o que sus poblaciones están socialmente fracturadas. La comparación entre un lugar que alberga a un marsupial amenazado, el kowari o rata marsupial de cola de pincel (Dasyuroides byrnei), y un lugar vecino, de donde falta el kowari, es concordante con el patrón que sugerimos. Palabras clave: Envenenamiento con 1080, Canis lupus dingo, Dasyuroides byrnei, Especie invasora, Control por predador, Superpredador.The introduction of alien mesopredators and herbivores has been implicated as the main driver of mammalian extinction in Australia. Recent studies suggest that the devastating effects of invasive species are mitigated by top–order predators. The survival of many threatened species may therefore depend on the presence and ecological functioning of large predators. Australia’s top predator, the dingo (Canis lupus dingo), has been intensively persecuted across the continent and it is extremely rare to find dingo populations that are not being subjected to lethal control. We predicted that the presence of threatened species point out places where dingo populations are relatively intact, and that their absence may indicate that dingoes are either rare or socially fractured. A comparison of a site which harbors a threatened marsupial, the kowari (Dasyuroides byrnei), and a neighboring site where the kowari is absent, offers support for this suggested pattern. Key words: 1080 poison–baiting, Canis lupus dingo, Dasyuroides byrnei, Invasive species, Predator control, Top predator.Se ha considerado la introducción de mesopredadores y herbívoros extranjeros como el principal desencadenante de la extinción de mamíferos australianos. Estudios recientes sugieren que los efectos devastadores de las especies invasoras quedan mitigados por los superpredadores. Por lo tanto, la supervivencia de muchas especies amenazadas puede depender de la presencia y funcionalidad ecológica de los grandes predadores. El superpredador australiano, el dingo (Canis lupus dingo) ha sido muy perseguido por todo el continente, y es extremadamente raro encontrar poblaciones de dingos que no estén sujetas a un control letal. En este estudio pronosticamos que la presencia de especies amenazadas señala los lugares donde las poblaciones de dingos están relativamente intactas, y que su ausencia puede indicar que los dingos son raros o que sus poblaciones están socialmente fracturadas. La comparación entre un lugar que alberga a un marsupial amenazado, el kowari o rata marsupial de cola de pincel (Dasyuroides byrnei), y un lugar vecino, de donde falta el kowari, es concordante con el patrón que sugerimos. Palabras clave: Envenenamiento con 1080, Canis lupus dingo, Dasyuroides byrnei, Especie invasora, Control por predador, Superpredador

Threatened species indicate hot-spots of top-down regulation

The introduction of alien mesopredators and herbivores has been implicated as the main driver of mammalian extinction in Australia. Recent studies suggest that the devastating effects of invasive species are mitigated by top-order predators. The survival of many threatened species may therefore depend on the presence and ecological functioning of large predators. Australia’s top predator, the dingo (Canis lupus dingo), has been intensively persecuted across the continent and it is extremely rare to find dingo populations that are not being subjected to lethal control. We predicted that the presence of threatened species point out places where dingo populations are relatively intact, and that their absence may indicate that dingoes are either rare or socially fractured. A comparison of a site which harbors a threatened marsupial, the kowari (Dasyuroides byrnei), and a neighboring site where the kowari is absent, offers support for this suggested pattern

Four-qubit entanglement from string theory

We invoke the black hole/qubit correspondence to derive the classification of four-qubit entanglement. The U-duality orbits resulting from timelike reduction of string theory from D=4 to D=3 yield 31 entanglement families, which reduce to nine up to permutation of the four qubits.Comment: 4 pages, 1 figure, 2 tables, revtex; minor corrections, references adde

Uniqueness of Bessel models: the archimedean case

In the archimedean case, we prove uniqueness of Bessel models for general linear groups, unitary groups and orthogonal groups.Comment: 22 page

Locality-oblivious cache organization leveraging single-cycle multi-hop NoCs

Locality has always been a critical factor in on-chip data placement on CMPs as accessing further-away caches has in the past been more costly than accessing nearby ones. Substantial research on locality-aware designs have thus focused on keeping a copy of the data private. However, this complicatesthe problem of data tracking and search/invalidation; tracking the state of a line at all on-chip caches at a directory or performing full-chip broadcasts are both non-scalable and extremely expensive solutions. In this paper, we make the case for Locality-Oblivious Cache Organization (LOCO), a CMP cache organization that leverages the on-chip network to create virtual single-cycle paths between distant caches, thus redefining the notion of locality. LOCO is a clustered cache organization, supporting both homogeneous and heterogeneous cluster sizes, and provides near single-cycle accesses to data anywhere within the cluster, just like a private cache. Globally, LOCO dynamically creates a virtual mesh connecting all the clusters, and performs an efficient global data search and migration over this virtual mesh, without having to resort to full-chip broadcasts or perform expensive directory lookups. Trace-driven and full system simulations running SPLASH-2 and PARSEC benchmarks show that LOCO improves application run time by up to 44.5% over baseline private and shared cache.Semiconductor Research CorporationUnited States. Defense Advanced Research Projects Agency (Semiconductor Technology Advanced Research Network

Transfer of K-types on local theta lifts of characters and unitary lowest weight modules

In this paper we study representations of the indefinite orthogonal group O(n,m) which are local theta lifts of one dimensional characters or unitary lowest weight modules of the double covers of the symplectic groups. We apply the transfer of K-types on these representations of O(n,m), and we study their effects on the dual pair correspondences. These results provide examples that the theta lifting is compatible with the transfer of K-types. Finally we will use these results to study subquotients of some cohomologically induced modules

A general form of Gelfand-Kazhdan criterion

We formalize the notion of matrix coefficients for distributional vectors in a representation of a real reductive group, which consist of generalized functions on the group. As an application, we state and prove a Gelfand-Kazhdan criterion for a real reductive group in very general settings.Comment: 16 pages, to appear in Manuscripta Mathematic

Polarizations and Nullcone of Representations of Reductive Groups

The paper starts with the following simple observation. Let V be a representation of a reductive group G, and let f_1,f_2,...,f_n be homogeneous invariant functions. Then the polarizations of f_1,f_2,...,f_n define the nullcone of k 0} h(t) x = 0 for all x in L. This is then applied to many examples. A surprising result is about the group SL(2,C) where almost all representations V have the property that all linear subspaces of the nullcone are annihilated. Again, this has interesting applications to the invariants on several copies. Another result concerns the n-qubits which appear in quantum computing. This is the representation of a product of n copies of $SL_2$ on the n-fold tensor product C^2 otimes C^2 otimes ... otimes C^2. Here we show just the opposite, namely that the polarizations never define the nullcone of several copies if n <= 3. (An earlier version of this paper, distributed in 2002, was split into two parts; the first part with the title ``On the nullcone of representations of reductive groups'' is published in Pacific J. Math. {bf 224} (2006), 119--140.