1,803 research outputs found

    Remarks on Charged Vortices in the Maxwell-Chern-Simons Model

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    We study vortex-like configuration in Maxwell-Chern-Simons Electrodynamics. Attention is paid to the similarity it shares with the Nielsen-Olesen solutions at large distances. A magnetic symmetry between a point-like and an azimuthal-like current in this framework is also pointed out. Furthermore, we address the issue of a neutral and spinless particle interacting with a charged vortex, and obtain that the Aharonov-Casher-type phase depends upon mass and distance parameters.Comment: New refs. added. Version accepted for publication in Phys. Lett.

    Stoichiometric regulation in micro- and mesozooplankton

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    Aquatic ecosystems experience large natural variation in elemental composition of carbon (C), nitrogen (N) and phosphorus (P), which is further enhanced by human activities. Primary producers typically reflect the nutrient ratios of their resource, whose stoichiometric composition can vary widely in conformity to environmental conditions. In contrast, C to nutrient ratios in consumers are largely constrained within a narrow range, termed homeostasis. In comparison to crustacean zooplankton, less is known about the ability of protozoan grazers and rotifer species to maintain stoichiometric balance. In this study, we used laboratory experiments with a primary producer (Nannochloropsis sp.), three different species of protozoan grazers and one mesozooplankton species: two heterotrophic dinoflagellates (Gyrodinium dominans and Oxyrrhis marina), a ciliate (Euplotes sp.) and a rotifer (Brachionus plicatilis) to test the stoichiometric response to five nutrient treatments. We showed that the dependency of zooplankton C:N:P ratios on C: nutrient ratios of their food source varies among species. Similar to the photoautotroph, the two heterotrophic dinoflagellates weakly regulated their internal stoichiometry. In contrast, the strength of stoichiometric regulation increased to strict homeostasis in both the ciliate and the rotifer, similar to crustacean zooplankton. Our study further shows that ciliate and rotifer growth can be constrained by imbalanced resource supply. It also indicates that these key primary consumers have the potential to trophically upgrade poor stoichiometric autotrophic food quality for higher trophic levels

    Review of the genus Ceresium Newman, 1842 (Coleoptera, Cerambycidae) in Fiji

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    A taxonomic review of the genus Ceresium (Coleoptera: Cerambycidae) found within the Fiji Islands is presented. A total of 17 species is treated. Full morphological descriptions and comparative images of each species are included, along with a dichotomous key for their identification

    Dasatinib as a treatment for Duchenne muscular dystrophy

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    Identification of a systemically acting and universal small molecule therapy for Duchenne muscular dystrophy would be an enormous advance for this condition. Based on evidence gained from studies on mouse genetic models, we have identified tyrosine phosphorylation and degradation of β-dystroglycan as a key event in the aetiology of Duchenne muscular dystrophy. Thus, preventing tyrosine phosphorylation and degradation of β-dystroglycan presents itself as a potential therapeutic strategy. Using the dystrophic sapje zebrafish, we have investigated the use of tyrosine kinase and other inhibitors to treat the dystrophic symptoms in this model of Duchenne muscular dystrophy. Dasatinib, a potent and specific Src tyrosine kinase inhibitor, was found to decrease the levels of β-dystroglycan phosphorylation on tyrosine and to increase the relative levels of non-phosphorylated β-dystroglycan in sapje zebrafish. Furthermore, dasatinib treatment resulted in the improved physical appearance of the sapje zebrafish musculature and increased swimming ability as measured by both duration and distance of swimming of dasatinib-treated fish compared with control animals. These data suggest great promise for pharmacological agents that prevent the phosphorylation of β-dystroglycan on tyrosine and subsequent steps in the degradation pathway as therapeutic targets for the treatment of Duchenne muscular dystrophy

    Responses of male Greater Prairie-Chickens to wind energy development

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    Citation: Winder, V. L., Gregory, A. J., McNew, L. B., & Sandercock, B. K. (2015). Responses of male Greater Prairie-Chickens to wind energy development. Condor, 117(2), 284-296. doi:10.1650/condor-14-98.1Renewable energy resources have received increased attention because of impacts of fossil fuels on global climate change. In Kansas, USA, optimal sites for wind energy development often overlap with preferred habitats of the Greater Prairie-Chicken (Tympanuchus cupido), a lek-mating prairie grouse of conservation concern. We tested for potential effects of energy development on male Greater Prairie-Chickens in north-central Kansas. We captured males at 23 leks located 0.04 to 28 km from wind turbines during a 2-yr preconstruction period (2007-2008) and a 3-yr postconstruction period (2009-2011). First, we tested for effects of proximity to turbines, habitat, and lek size on annual probability of lek persistence and changes in male numbers. We predicted that energy development might result in behavioral avoidance of areas close to turbines, resulting in increased rates of lek abandonment and fewer males attending surviving leks. We found that distance to turbine had a negative effect on lek persistence for leks,8 km from turbines during the postconstruction period, supporting the 8-km buffer zone recommended by the U.S. Fish and Wildlife Service as an offset for wind energy projects. Additionally, lek persistence was positively related to number of males counted at a lek and with grassland cover surrounding the lek. Second, we tested for effects of wind energy development on male body mass. We predicted that degraded habitat conditions might result in decreased body mass for males attending leks near turbines during the postconstruction period. Male body mass was similar to 2% lower during the postconstruction period, but distance to turbine did not affect body mass. Additional study is needed to determine whether short-term effects of turbines on lek persistence influence population viability of Greater Prairie-Chickens
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