5,975 research outputs found

    Founders\u27 Day 1957

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    Tropical occurrence and agricultural importance of Beauveria bassiana and Metarhizium anisopliae

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    Entomopathogenic fungi are often relied on as important components of integrated pest management in tropical agriculture, either as biopesticides or as naturally occurring microbes conserved in the environment. Tropical abiotic conditions are often well-suited for microbial growth, and tropical habitats can be teeming with microbial biodiversity. However, competitive interactions with other fungi and the need to overcome defenses of hosts adapted to high fungal loads may inhibit the ability of insect pathogens to control tropical pests. Here, we review the current literature on Beauveria bassiana and Metarhizium anisopliae inhabiting tropical environments and their potential use as biological control agents. In some cases there is not a clear distinction between temperate and tropical agroecosystems, such as in the level of organic matter or soil texture in agricultural soils. Therefore, the effects of these soil characteristics in temperate agroecosystems are likely applicable to tropical systems as well. In contrast, factors such as microbial biodiversity and seasonal fluctuation in environmental conditions can differ dramatically between temperate and tropical systems. Therefore, we discuss literature that can be generalized to tropical systems. Where temperate and tropical systems are likely to differ we synthesize the literature specifically for tropical agroecosystems. We also provide hypotheses to stimulate future work on latitudinal gradients and the relative importance of biotic and abiotic factors in governing entomopathogen prevalence and community composition. These hypotheses provide a path forward to developing theory guiding the conservation and augmentation of entomopathogenic fungi to prevent pest outbreaks

    The infection efficacy of Metarhizium strains (Hypocreales: Clavicipitaceae) against the Queensland fruit fly Bactrocera tryoni (Diptera: Tephritidae)

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    The Queensland fruit fly (Qfly), Bactrocera tryoni Froggatt, is a devastating pest of Australia's commercial fruit systems. Fruit fly mitigation is heavily centered around the use chemical insecticides, with limited investigation into microbial control alternatives. The wet tropics of northern Queensland is a highly biodiverse ecosystem containing many species of insect pathogenic fungi, but it is unclear whether any of these entomopathogens could contribute to Qfly management programs. In laboratory trials, we investigated the potential for Qfly microbial control by 3 locally sourced strains of entomopathogenic fungi comprising 2 species, Metarhizium guizhouense (Chen and Guo) and Metarhizium lepidiotae (Driver and Milner). Additionally, we evaluated 2 different inoculation methods to derive the most effective way to expose the flies to conidia-either through dry conidia or in a conidial suspension. All 3 strains were successful in causing Qfly mortality. Metarhizium lepidiotae resulted in the highest mean mortality over the trials, while M. guizhouense resulted in the highest mortality in a single replicate. Laboratory experiments revealed exposure through dry conidia to be the most effective method to inoculate the flies. These results suggest that fungal entomopathogens could be a viable pathway to Qfly suppression

    Electronic structure and magnetic state of transuranium metals under pressure

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    Electronic structure of bcc Np, fcc Pu, Am, and Cm pure metals under pressure has been investigated employing the LDA+U method with spin-orbit coupling (LDA+U+SO). Magnetic state of the actinide ions was analyzed in both LS and jj coupling schemes to reveal the applicability of corresponding coupling bases. It was demonstrated that whereas Pu and Am are well described within the jj coupling scheme, Np and Cm can be described appropriately neither in {m-sigma}, nor in {jmj} basis, due to intermediate coupling scheme realizing in these metals that requires some finer treatment. The LDA+U+SO results for the considered transuranium metals reveal bands broadening and gradual 5f electron delocalization under pressure.Comment: 5 pages, 5 figure

    Whey Versus Casein Supplementation in Physically Active, Healthy Individuals

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    Purpose: Research shows the benefits of whey isolate protein powder and casein protein powder supplementation in regard to body composition and resting metabolic rate; however, minimal research exists comparing the effectiveness of whey to casein supplementation. Methods: Eighteen (18) physically trained, healthy individuals (23±3.1 yrs.; 171.7cm; 12 males; 6 females) completed a randomized two condition [Combat 100% Isolate (Whey) versus Combat 100% (Casein)] by two time point [Pre-, Post-] intervention. The intervention consisted of subjects supplementing on either whey or casein in conjunction with resistance training over an 8-week period. Pre and post testing included % body fat and metabolic rate. Results: A 2x2, repeated-measures analysis of variance (ANOVA) demonstrated non-significant (p ≥ 0.05) effects on changes in % body fat and resting metabolic rate following the 8-week intervention. Conclusions: The data concludes no differences in the effects of whey versus casein protein supplementation in physically active, healthy individual

    Current-voltage characteristics of quasi-one-dimensional superconductors: An S-curve in the constant voltage regime

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    Applying a constant voltage to superconducting nanowires we find that its IV-characteristic exhibits an unusual S-behavior. This behavior is the direct consequence of the dynamics of the superconducting condensate and of the existence of two different critical currents: j_{c2} at which the pure superconducting state becomes unstable and j_{c1}<j_{c2} at which the phase slip state is realized in the system.Comment: 4 pages, 5 figures, replaced with minor change

    Antiferromagnetic order and dielectric gap within the vortex core of antiferromagnetic superconductor

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    The structure of a superconducting vortex has been studied theoretically for a dirty antiferromagnetic superconductor (AFSC), modelling an AFSC as a doped semi-metal with s-wave superconducting pairing and antiferromagnetic (dielectric) interaction between electrons (holes). It is also supposed that the quasiparticles dispersion law possesses the property of nesting. The distribution of the superconducting and magnetic order parameters near the vortex core is calculated. It is shown that the antiferromagnetic order, been suppressed at large distances, is restored around the superconducting flux and the vortex core is in fact insulating and antiferromagnetic, in stark contrast to the normal metal cores of traditional superconductors. Moreover, our model calculations predict that as the temperature decreases the flux region of the superconductivity and antiferromagnetism coexistence increases.Comment: 9 pages, 3 Postscript figures,NATO Advanced Research Workshop on "Vortex dynamics in superconductors and other complex systems" Yalta, Crimea, Ukraine, 13-17 September 200

    Photobiomodulation of human dermal fibroblasts in vitro: decisive role of cell culture conditions and treatment protocols on experimental outcome

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    YesPhotobiomodulation-based (LLLT) therapies show tantalizing promise for treatment of skin diseases. Confidence in this approach is blighted however by lamentable inconsistency in published experimental designs, and so complicates interpretation. Here we interrogate the appropriateness of a range of previously-reported treatment parameters, including light wavelength, irradiance and radiant exposure, as well as cell culture conditions (e.g., serum concentration, cell confluency, medium refreshment, direct/indirect treatment, oxygen concentration, etc.), in primary cultures of normal human dermal fibroblasts exposed to visible and near infra-red (NIR) light. Apart from irradiance, all study parameters impacted significantly on fibroblast metabolic activity. Moreover, when cells were grown at atmospheric O2 levels (i.e. 20%) short wavelength light inhibited cell metabolism, while negligible effects were seen with long visible and NIR wavelength. By contrast, NIR stimulated cells when exposed to dermal tissue oxygen levels (approx. 2%). The impact of culture conditions was further seen when inhibitory effects of short wavelength light were reduced with increasing serum concentration and cell confluency. We conclude that a significant source of problematic interpretations in photobiomodulation reports derives from poor optimization of study design. Further development of this field using in vitro/ex vivo models should embrace significant standardization of study design, ideally within a design-of-experiment setting
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