Ruin models with investment income

This survey treats the problem of ruin in a risk model when assets earn investment income. In addition to a general presentation of the problem, topics covered are a presentation of the relevant integro-differential equations, exact and numerical solutions, asymptotic results, bounds on the ruin probability and also the possibility of minimizing the ruin probability by investment and possibly reinsurance control. The main emphasis is on continuous time models, but discrete time models are also covered. A fairly extensive list of references is provided, particularly of papers published after 1998. For more references to papers published before that, the reader can consult [47].Comment: Published in at http://dx.doi.org/10.1214/08-PS134 the Probability Surveys (http://www.i-journals.org/ps/) by the Institute of Mathematical Statistics (http://www.imstat.org

On the rationality of quadric surface bundles

For any standard quadric surface bundle over $\mathbb P^2$, we show that the locus of rational fibres is dense in the moduli space.Comment: 20 pages; to appear in Annales de l'Institut Fourie

A new species and new records of Aphodius Illiger (Coleoptera: Scarabaeidae: Aphodiinae) from mammal burrows in Nebraska

Direct sampling of rodent burrows in Nebraska resulted in the collection of 16 species of Aphodius Illiger previously unknown from the state, including specimens of four undescribed species. One of these species is described here as new: Aphodius viceversus new species recorded from Nebraska and Kansas. Other Aphodius species recorded from Nebraska for the first time include A. acuminatus Cartwright, A. anomaliceps Brown, A. carri Brown, A. criddlei Brown, A. kirni Cartwright, A. kiowensis Gordon and Salsbury, A. magnificens Robinson, A. neodistinctus Brown, A. peculiosus Schmidt, A. punctissimus Brown, A. thomomysi Brown, and A. leptotarsis Brown. Collecting information is summarized for each species

Improving green-house gas balances of organic farms by the use of straight vegetable oil from mixed cropping as farm own fuel and its competition to food production

Verbesserung der Treibhausgasbilanzen ökologischer Betriebe durch die Nutzung von Pflanzenöl aus dem Mischfruchtanbau als hofeigene Biokraftstoff und die Konkurrenz zur Nahrungsmittelproduktion

Syndetic Sets and Amenability

We prove that if an infinite, discrete semigroup has the property that every right syndetic set is left syndetic, then the semigroup has a left invariant mean. We prove that the weak*-closed convex hull of the two-sided translates of every bounded function on an infinite discrete semigroup contains a constant function. Our proofs use the algebraic properties of the Stone-Cech compactification

A new species of Parochodaeus Nikolajev from the southwestern United States (Coleoptera: Scarabaeoidea: Ochodaeidae)

A new species of Parochodaeus Nikolajev (Scarabaeoidea: Ochodaeidae) with extremely small adults is described from west Texas, P. pixius Paulsen. The species is compared with the sympatric P. biarmatus (LeConte), to which it is most similar in size

A new genus for the Neotropical species of Aesalus Fabricius, with descriptions of eight new species (Coleoptera: Lucanidae: Aesalinae)

The Neotropical members of the genus Aesalus Fabricius (Coleoptera: Lucanidae: Aesalinae) are transferred to a new genus, Trogellus, due to their morphological dissimilarity and molecular divergence from the Old World species of Aesalus, and the new genus is revised. A neotype is designated for A. trogoides Albers and a lectotype for A. neotropicalis Bates. Aesalus smithi Bates is placed into synonymy with Aesalus trogoides, new synonymy. Two new combinations result from the transfer of species formerly in Aesalus: Trogellus trogoides from Mexico and Trogellus neotropicalis from Guatemala. In addition to the two known species, eight new species are described: T. catrachitus, T. chapinitus, T. hawksi, T. herrmanni, T. maesi, T. narizotus, T. ticiticus, and T. trifinius. This brings the total number of species of Central American aesalines to ten. A phylogeny of Aesalini based on two gene regions of ribosomal DNA is presented. Due to clear morphological differences and large molecular divergence between species groups, two additional new subgenera of Trogellus are proposed: Mayaesalus and Trogoides

Nomenclatural changes in the Nearctic Ochodaeinae and description of two new genera (Coleoptera: Scarabaeoidea: Ochodaeidae)

Generic placement of Nearctic species of Ochodaeinae has lagged behind changes in generic concepts in the group. In order to place Nearctic species into the appropriate genus-level taxa, several nomenclatural changes are made. The new generic name Xenochodaeus is proposed for species with an elongate, subparallel sulcus on the propygidium and a longitudinally impressed mentum. The genus contains 6 species. Xenochodaeus americanus (Westwood), new combination, is valid and is removed from synonymy with X. musculus (Say), new combination. A neotype is designated for Odontaeus musculus. Ochodaeus opacus LeConte is synonymized under X. americanus. Other new combinations include Xenochodaeus luscinus (Howden), X. planifrons (Schaeffer), X. simplex (LeConte), and X. ulkei (Horn). The new generic name Cucochodaeus is proposed for species having the propygidial sulcus absent, stridulatory peg absent, and possessing 9 antennomeres. The genus contains 1 species, C. sparsus (LeConte), new combination. Ochodaeus mandibularis Linell is placed into synonymy with C. sparsus. Ochodaeus gnatho Fall is transferred to the genus Codocera Eschscholtz, resulting in C. gnatho (Fall), new combination. Two new combinations result from Nearctic species transferred to Neochodaeus Nikolajev: N. repandus (Fall) and N. striatus (LeConte). Three Nearctic species are transferred to Parochodaeus Nikolajev, resulting in new combinations: Parochodaeus californicus (Horn), P. duplex (LeConte), and P. peninsularis (Horn). A lectotype is designated for Ochodaeus kansanus Fall, and that same specimen is designated as the neotype of Ochodaeus duplex (LeConte), objectively synonymizing O. kansanus with O. duplex. A checklist of Nearctic species and key to Nearctic genera are provided