A portable tent-cage for entomological field studies

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A note on sexing live specimens of Scolytus unispinosus Lec. (Scolytidae, Coleoptera)

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Influence of Logging on Douglas Fir Beetle Populations

All species of bark beetles of economic importance prefer to attack freshly-killed host material. Logging slash, wind-throw, and fire-killed timber provide ideal breeding grounds for bark beetles. A few species, mostly in the Dendroctonus group, are able to kill living trees. When beetles in the group, raised in preferred host material, cannot find any or enough freshly-killed trees, logs, or slash to enter, they may attack living trees. In the interior of British Columbia, infestations of the Douglas fir beetle can often be traced to logging disturbance

Bark beetles, Pseudohylesinus spp. (Coleoptera: Scolytidae), associated with amabilis fir defoliated by Neodiprion sp. (Hymenoptera: Diprionidae)

Only Abies amabilis (Dougl.) Forbes heavily defoliated by a sawfly, Neodiprion sp., supported broods of Pseudohylesinus spp.. Although many trees with less defoliation showed evidence of attack, usually it was caused by adult beetles making overwintering niches. P. granulatus (Leconte) was found on the lower bole, whereas P. grandis Swaine and P. nobilis Swaine were found on the upper bole. Defoliated Tsuga heterophylla (Raf.) Sarg. were not attacked by bark beetles

A common cause for a common phenotype : the gatekeeper hypothesis in fetal programming

Copyright © 2011 Elsevier Ltd. All rights reserved.Peer reviewedPublisher PD

Thurston's pullback map on the augmented Teichm\"uller space and applications

Let $f$ be a postcritically finite branched self-cover of a 2-dimensional topological sphere. Such a map induces an analytic self-map $\sigma_f$ of a finite-dimensional Teichm\"uller space. We prove that this map extends continuously to the augmented Teichm\"uller space and give an explicit construction for this extension. This allows us to characterize the dynamics of Thurston's pullback map near invariant strata of the boundary of the augmented Teichm\"uller space. The resulting classification of invariant boundary strata is used to prove a conjecture by Pilgrim and to infer further properties of Thurston's pullback map. Our approach also yields new proofs of Thurston's theorem and Pilgrim's Canonical Obstruction theorem.Comment: revised version, 28 page

Field techniques for rearing and marking mountain pine beetle for use in dispersal studies

Mountain pine beetles, Dendroctonus ponderosae, were marked with fluorescent (DayGlo) powders in vacuum chambers and on powder-covered brood trees in the field for use in release-recapture studies of dispersal behaviour. A large wall tent was used as a field insectary to accelerate late stages of development of large numbers of beetles in naturally infested bolts of lodgepole pine. Up to 28% of the marked beetles which flew were recovered from lethal trap trees. Beetles self-marked on powdered brood trees were captured in barrier traps in predicted proportions

Photoemission Beyond the Sudden Approximation

The many-body theory of photoemission in solids is reviewed with emphasis on methods based on response theory. The classification of diagrams into loss and no-loss diagrams is discussed and related to Keldysh path-ordering book-keeping. Some new results on energy losses in valence-electron photoemission from free-electron-like metal surfaces are presented. A way to group diagrams is presented in which spectral intensities acquire a Golden-Rule-like form which guarantees positiveness. This way of regrouping should be useful also in other problems involving spectral intensities, such as the problem of improving the one-electron spectral function away from the quasiparticle peak.Comment: 18 pages, 11 figure

Monodromy of Cyclic Coverings of the Projective Line

We show that the image of the pure braid group under the monodromy action on the homology of a cyclic covering of degree d of the projective line is an arithmetic group provided the number of branch points is sufficiently large compared to the degree.Comment: 47 pages (to appear in Inventiones Mathematicae