2,698 research outputs found

    First North American record of the Palaearctic rhinophorid Stevenia deceptoria (Loew) (Diptera: Rhinophoridae)

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    The Rhinophoridae (Diptera) have a cosmopolitan distribution and a known fauna of about 150 species (Cerretti & Pape 2007). So far as known, all species are parasitoids of terrestrial woodlice (sow bugs) of the order Isopoda (Oniscoidea) (Pape 2010). Female rhinophorids lay eggs in the vicinity of potential hosts and the planidial first instars parasitize sow bugs as they pass by (Pape 1998). The only rhinophorids native to North America belong to the genera Apomorphyto Cerretti, Lo Giudice & Pape (with one described species from Costa Rica and an undetermined species from Nicaragua) and Bezzimyia Townsend (Pape 2010; Cerretti et al. 2014). Bezzimyia is a mostly Neotropical genus of 17 known species with two species reaching the southern United States (Texas and Arizona) (Pape & Arnaud 2001). Recently, the monophyly of Bezzimyia was called into question but the limits of the genus have yet to be formally revised (Cerretti et al. 2014). Two rhinophorids are well known as introductions from the Palaearctic Region, Melanophora roralis (Linnaeus) and Phyto discrepans Pandellé, with the former widespread in eastern North America, West Indies and South America (Crosskey 1977; Pape 2010) and the latter known only from Newfoundland (Canada) (Wood 1987). A key to separate the two species was given by Wood (1987). The genus Stevenia Robineau-Desvoidy is currently known from 23 species, all native to the Old World and most diverse in the West Palaearctic Region (Cerretti & Pape 2007). One species native to Europe and North Africa, Stevenia deceptoria (Loew), was reported recently as an introduction to Argentina by Mulieri et al. (2010). The authors recorded the species from several locations within Buenos Aires Province and hypothesized that it became established through the introduction of parasitized woodlice originating from the Palaearctic Region. Introduced woodlice are common in the New World (Jass & Klausmeier 2000) and parasitized immigrants or transported puparia most likely account for the presence of all three exotic rhinophorid species in North America. Mulieri et al. (2010) summarized the Palaearctic distribution of S. deceptoria, gave locality records of the species in Argentina, and provided a key to the five genera of Rhinophoridae known from the New World. Here we report another finding of Stevenia deceptoria in the Americas, this time from Ohio in North America. All records are from a single locality, the backyard of author GAD. Specimens were caught in a six metre Malaise trap (BioQuip® Products, Inc.) and killed in the trap head using a small piece of Hot Shot® No-Pest® Strip [active ingredient 2,2-dichlorovinyl dimethyl phosphate 18.6%]. Trap samples were frozen and later sorted, with selected Diptera subsequently pinned and labeled. The first two specimens of S. deceptoria to be detected were removed, pinned, and labeled by JEOH and identified as S. deceptoria by PC (Cerretti & Pape 2007) (one of these specimens is shown in Fig. 1). Additional specimens were later found in earlier and later samples by GAD. Specimens are housed in the Canadian National Collection of Insects, Ottawa, Canada (CNC) and the personal collection of Gregory Dahlem, Cincinnati, USA (GAD)

    Realization of a Resonant Fermi Gas with a Large Effective Range

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    We have measured the interaction energy and three-body recombination rate for a two-component Fermi gas near a narrow Feshbach resonance and found both to be strongly energy dependent. Even for deBroglie wavelengths greatly exceeding the van der Waals length scale, the behavior of the interaction energy as a function of temperature cannot be described by atoms interacting via a contact potential. Rather, energy-dependent corrections beyond the scattering length approximation are required, indicating a resonance with an anomalously large effective range. For fields where the molecular state is above threshold, the rate of three-body recombination is enhanced by a sharp, two-body resonance arising from the closed-channel molecular state which can be magnetically tuned through the continuum. This narrow resonance can be used to study strongly correlated Fermi gases that simultaneously have a sizeable effective range and a large scattering length.Comment: to appear in Phys. Rev. Let

    All-Optical Production of a Degenerate Fermi Gas

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    We achieve degeneracy in a mixture of the two lowest hyperfine states of 6^6Li by direct evaporation in a CO2_2 laser trap, yielding the first all-optically produced degenerate Fermi gas. More than 10510^5 atoms are confined at temperatures below 4ÎĽ4 \muK at full trap depth, where the Fermi temperature for each state is 8ÎĽ8 \muK. This degenerate two-component mixture is ideal for exploring mechanisms of superconductivity ranging from Cooper pairing to Bose condensation of strongly bound pairs.Comment: 4 pgs RevTeX with 2 eps figs, to be published in Phys. Rev. Let

    Inducing metamorphosis in the irukandji jellyfish Carukia barnesi

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    Here we utilize chemical ecology as a tool to manipulate the biological system of a small, but highly venomous to humans, cubozoan jellyfish, Carukia barnesi. We trialled a range of chemical reagents including indole compounds, 9-cis-retinoic acid and lugols solution to induce metamorphosis between the polyp and medusa life stages. An optimum method was determined resulting in a 90% metamorphosis rate to healthy medusa by exposing the polyps to 1 μM of 5-methoxy-2-methylindole for 24 h. Of note is that chemical exposure time significantly impacts health and metamorphosis rates in this species. We also present a theoretical mechanism for the chemical/biological interactions occurring during metamorphosis. This is a significant methodological advancement which now enables rearing of this animal en mass in aquaria—a world first for this species—which will subsequently supply and facilitate venom research into this understudied jellyfish

    A review of genus-group names in Diptera (Insecta) that J.C. Fabricius "borrowed" from other dipterists and proposed as new in his systematic works from 1775 to 1805

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    Michelsen, Verner, O'Hara, James E. (2014): A review of genus-group names in Diptera (Insecta) that J.C. Fabricius "borrowed" from other dipterists and proposed as new in his systematic works from 1775 to 1805. Zootaxa 3873 (1): 73-81, DOI: http://dx.doi.org/10.11646/zootaxa.3873.1.

    Phase-field approach to heterogeneous nucleation

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    We consider the problem of heterogeneous nucleation and growth. The system is described by a phase field model in which the temperature is included through thermal noise. We show that this phase field approach is suitable to describe homogeneous as well as heterogeneous nucleation starting from several general hypotheses. Thus we can investigate the influence of grain boundaries, localized impurities, or any general kind of imperfections in a systematic way. We also put forward the applicability of our model to study other physical situations such as island formation, amorphous crystallization, or recrystallization.Comment: 8 pages including 7 figures. Accepted for publication in Physical Review
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