20,769 research outputs found
A new Potamobates Champion species (Heteroptera: Gerridae) from Ecuador with new distribution records for P. williamsi
Potamobates sumaco new species is described from the Ecuadorian Amazon. Male and female genitalia differentiate P. sumaco from a similar parapatric species, P. williamsi Hungerford. Phylogenetic analysis indicates P. sumaco is closely related to the species of the P. tridentatus group which includes P. williamsi. A distribution map and revised key to Potamobates species are provided.Se describe Potamobates sumaco nueva especies del Amazonas Ecuatoriano. Los genitales del macho y la hembra distinguen P. sumaco de la especie mas cercana P. williamsi Hungerford. El analisis filogenetico indica que P. sumaco partenece al grupo P. tridentatus. Se incluye un mapa de la distribucion y una clave modificada para la identificacion de las especies de Pomatombates
Tribological Behavior of Very Thin Confined Films
The tribological properties of two smooth surfaces in the presence of a thin
confined film are investigated with a generic model for the interaction between
two surfaces and with computer simulations. It is shown that at large normal
contact pressures, an ultra thin film automatically leads to static friction
between two flat surfaces - even if the surfaces are incommensurate.
Commensurability is nevertheless the key quantity to understand the
tribological behavior of the contact. Qualitative differences between
commensurate and incommensurate contacts remain even in the presence of a thin
film. The differences mainly concern the thermal diffusion of the contact and
the transition between smooth sliding and stick-slip.Comment: 7 pages, 6 figure
Ciidae of Michigan (Insecta: Coleoptera)
The family Ciidae Leach, 1819, occurs worldwide with approximately 720 species. In the United States there are 84 species in 13 genera. Given their relatively small size (~0.5 to 6 mm) and cryptic habitats, feeding in decaying fungi, recent regional fauna studies are lacking including the northeastern United States. To alleviate this gap in knowledge, in part, we review and identify 2,123 undetermined specimens collected in Michigan. We provide new state records for four species: Ceracis pecki Lawrence 1971, Cis americanus Mannerheim, 1852, Cis submicans Abeille de Perrin, 1874, Dolicocis manitoba Dury, 1919 which increases the total for Michigan to 25 species and update records for Michigan counties. In addition, we provide a modified key to Michigan species
A taxonomic revision of Camptocerus Dejean (Coleoptera: Curculionidae: Scolytinae)
The Neotropical ambrosia beetle genus Camptocerus Dejean was revised. Monophyly of the genus was tested using 66 morphological characters in a cladistic analysis. Camptocerus was recovered as monophyletic and 31 species were recognized. Six new synonyms were discovered: C. auricomus Blandford 1896 (= C. striatulus Hagedorn 1905), C. inoblitus (Schedl) 1939 (= C. morio (Schedl) 1952), C. niger (Fabricius) 1801 (= C. tectus Eggers 1943), C. opacicollis (Eggers) 1929 (= C. infidelis Wood 1969; = C. uniseriatus Schedl 1972), C. suturalis (Fabricius) 1801 (= C. cinctus Chapuis 1869). Two species were removed from synonymy: C. charpentierae Schedl and C. hirtipennis Schedl. Twelve new species of Camptocerus were described: C. coccoformus (Brazil, Ecuador), C. distinctus (Ecuador), C. doleae (Ecuador), C. igniculus (Brazil), C. mallopterus (Ecuador), C. noel (widely distributed across Amazonia), C. petrovi (Ecuador), C. pilifrons (Ecuador), C. pseudoangustior (widely distributed across Amazonia), C. satyrus (Brazil), C. unicornus (Brazil) and C. zucca (Ecuador). Lectotypes are here designated for the following species: Camptocerus auricomus Blandford, Camptocerus squammiger Chapuis, Hylesinus gibbus Fabricius, Hylesinus suturalis Fabricius, Hylesinus fasciatus Fabricius. A key, diagnosis, distribution, host records and images were provided for each species
In vivo analysis of NHPX reveals a novel nucleolar localization pathway involving a transient accumulation in splicing speckles
The NHPX protein is a nucleolar factor that binds directly to a conserved RNA target sequence found in nucleolar box C/D snoRNAs and in U4 snRNA. Using enhanced yellow fluorescent protein (EYFP)– and enhanced cyan fluorescent protein–NHPX fusions, we show here that NHPX is specifically accumulated in both nucleoli and Cajal bodies (CBs) in vivo. The fusion proteins display identical localization patterns and RNA binding specificities to the endogenous NHPX. Analysis of a HeLa cell line stably expressing EYFP–NHPX showed that the nucleolar accumulation of NHPX was preceded by its transient accumulation in splicing speckles. Only newly expressed NHPX accumulated in speckles, and the nucleolar pool of NHPX did not interchange with the pool in speckles, consistent with a unidirectional pathway. The transient accumulation of NHPX in speckles prior to nucleoli was observed in multiple cell lines, including primary cells that lack CBs. Inhibitor studies indicated that progression of newly expressed NHPX from speckles to nucleoli was dependent on RNA polymerase II transcription, but not on RNA polymerase I activity. The data show a specific temporal pathway involving the sequential and directed accumulation of NHPX in distinct subnuclear compartments, and define a novel mechanism for nucleolar localization
The Woodlouse Hunter Occurs in Michigan (Araneae: Dysderidae: \u3ci\u3eDysdera Crocata\u3c/i\u3e C.l. Koch 1838)
We document the occurrence of the spider, Dysdera crocata C.L. Koch, in Michigan. Specimens have been collected from Bay, Branch, Ingham, Kent, Livingston, Macomb, Montcalm, Muskegon, Oakland, Washtenaw and Wayne Counties between 1975-2013
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