73 research outputs found
Magneto-optical spectra of closely spaced magnetite nanoparticles
The Faraday rotation spectrum of composites containing magnetite nanoparticles is found to be dependent on the interparticle spacing of the constituent nanoparticles. The composite materials are prepared by combining chemically synthesized Fe
3O4 smagnetited nanoparticles s8-nm diameterd and polysmethylmethacrylated . Composites are made containing a range of nanoparticle concentrations. The peak of the main spectral feature depends on nanoparticle concentration; this peak is observed to shift from approximately 470 nm for sdilute compositesd to 540 nm concentrated . We present a theory based on the discrete-dipole approximation which accounts for
optical coupling between magnetite particles. Qualitative correlations between theoretical calculations and experimental data suggest that the shifts in spectral peak position depend on both interparticle distance and geometrical configuratio
Meta-analysis of yield response of foliar fungicide-treated hybrid corn in the United States and Ontario, Canada
Foliar fungicide applications to corn (Zea mays L.) occur at one or more application timings ranging from early vegetative growth stages to mid-reproductive stages. Previous studies indicated that fungicide applications are profitable under high disease pressure when applied during the tasseling to silking growth stages. Few comprehensive studies in corn have examined the impact of fungicide applications at an early vegetative growth stage (V6) compared to late application timings (VT) for yield response and return on fungicide investment (ROI) across multiple locations
Meta-analysis of yield response of foliar fungicide-treated hybrid corn in the United States and Ontario, Canada
Background
Foliar fungicide applications to corn (Zea mays L.) occur at one or more application timings ranging from early vegetative growth stages to mid-reproductive stages. Previous studies indicated that fungicide applications are profitable under high disease pressure when applied during the tasseling to silking growth stages. Few comprehensive studies in corn have examined the impact of fungicide applications at an early vegetative growth stage (V6) compared to late application timings (VT) for yield response and return on fungicide investment (ROI) across multiple locations.
Objective
Compare yield response of fungicide application timing across multiple fungicide classes and calculate the probability of positive ROI.
Methods
Data were collected specifically for this analysis using a uniform protocol conducted in 13 states in the United States and one province in Canada from 2014–2015. Data were subjected to a primary mixed-model analysis of variance. Subsequent univariate meta-analyses, with and without moderator variables, were performed using standard meta-analytic procedures. Follow-up power and prediction analyses were performed to aid interpretation and development of management recommendations.
Results
Fungicide application resulted in a range of yield responses from -2,683.0 to 3,230.9 kg/ha relative to the non-treated control, with 68.2% of these responses being positive. Evidence suggests that all three moderator variables tested (application timing, fungicide class, and disease base level), had some effect (α = 0.05) on the absolute difference in yield between fungicide treated and non-treated plots (). Application timing influenced , with V6 + VT and the VT application timings resulting in greater yield responses than the V6 application timing alone. Fungicide formulations that combined demethylation inhibitor and quinone outside inhibitor fungicides significantly increased yield response.
Conclusion
Foliar fungicide applications can increase corn grain yield. To ensure the likelihood of a positive ROI, farmers should focus on applications at VT and use fungicides that include a mix of demethylation inhibitor and quinone outside inhibitor active ingredients
Dried Blood Spheroids for Dry-State Room Temperature Stabilization of Microliter Blood Samples
It is well-known that 2D dried blood spots on paper offer a facile sample collection, storage, and transportation of blood. However, large volume requirements, possible analyte instability, and difficult sample recovery plague this method, lowering confidence in analyte quantification. For the first time, we demonstrate a new approach using 3D dried blood spheroids for stabilization of small volume blood samples, mitigating these effects without cold storage. Blood spheroids form on hydrophobic paper, preventing interaction between the sample and paper substrate, eliminating all chromatographic effects. Stability of the enzyme alanine transaminase and labile organic compounds such as cocaine and diazepam were also shown to increase in the spheroid by providing a critical radius of insulation. On-surface analysis of the dried blood spheroids using paper spray mass spectrometry resulted in sub-ng/mL limits of detection for all illicit drugs tested, representing 1 order of magnitude improvement compared with analysis from 2D dried blood spots
“An important cog in the wheel”, but not the driver: Coaches’ perceptions of their role in doping prevention
Objectives: Under the World Anti-Doping Code coaches have designated anti-doping roles and responsibilities. Yet, their experiences, opinions and behaviours in relation to these expectations are poorly understood. This study responds directly to this absence of evidence in order to move the field forward. Design: A qualitative thematic analysis approach. Method: Twelve football and rugby league coaches, working in a performance development context, took part in semi-structured interviews to explore their (anti-)doping experiences, opinions and behaviours. Nine coaches participated in follow-up interviews where particular attention was paid to existing anti-doping policy directives. All interviews were analysed using inductive thematic analysis. Results: Coaches were supportive of anti-doping efforts and exerted their influence by monitoring, giving advice and creating the ‘right’ culture. Performance prioritisation rendered coaches reluctant to engage proactively in addressing anti-doping in their practice; a situation exacerbated by a lack of self-efficacy to advise/act in accordance with the rules. Consequently, coaches tended to rely on others (both internally and externally to their club) to provide anti-doping support, and anti-doping is deemed unnecessary/irrelevant. Critically, coaches’ current behaviours were not driven by policy, as they were unaware of expectations and consequences outlined in the Code. Conclusions: Coaches are willing to support anti-doping efforts, but are generally passive in their everyday practice. The gulf between anti-doping policy and coaching practice raises cause for concern for anti-doping policy makers. To bridge this gap systematic programming of activities designed to ensure coaches are able and willing to take a proactive role in doping prevention is required
Comics, graphic narratives, and lesbian lives
Lesbian comics and graphic narratives have gained unprecedented cultural
presence in the twenty-first century. Yet despite the surge in interest in the work of artists such as Alison Bechdel, and despite the existence of a substantial online archive about lesbian comics created by artists, readers, and collectors, relatively little critical attention has been directed to this work. The chapter begins to fill this gap. Taking the Bechdel’s work as its start-and-end point, it provides an overview of major developments in lesbian comics and contextualises them including in relation to the gendered conditions of possibility that define comics culture
An Alternative Neo-Kohlbergian Approach in Social Pedagogy
In many countries social pedagogues apply ART (Aggression Replacement Training), a multimodal programme designed to help juveniles with severe behaviour problems. In this programme Lawrence Kohlberg’s theory of moral development makes up an important element. The first part of this article offers a presentation of Kohlberg’s theory and some of the critique made of it. The second part describes how the Kohlbergian tradition is implemented in ART. In the final part of the article a problem with the ART programme is pointed out and an alternative neo-Kohlbergian approach is described. This method may prove to be a viable approach in the field of social pedagogy and an adequate supplement to the ART programme
Finishing the euchromatic sequence of the human genome
The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead
SBML Level 3: an extensible format for the exchange and reuse of biological models
Systems biology has experienced dramatic growth in the number, size, and complexity of computational models. To reproduce simulation results and reuse models, researchers must exchange unambiguous model descriptions. We review the latest edition of the Systems Biology Markup Language (SBML), a format designed for this purpose. A community of modelers and software authors developed SBML Level 3 over the past decade. Its modular form consists of a core suited to representing reaction-based models and packages that extend the core with features suited to other model types including constraint-based models, reaction-diffusion models, logical network models, and rule-based models. The format leverages two decades of SBML and a rich software ecosystem that transformed how systems biologists build and interact with models. More recently, the rise of multiscale models of whole cells and organs, and new data sources such as single-cell measurements and live imaging, has precipitated new ways of integrating data with models. We provide our perspectives on the challenges presented by these developments and how SBML Level 3 provides the foundation needed to support this evolution
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Mechanical, electromechanical, and optical properties of germanium nanowires
textIn order to completely assess the potential of semiconductor nanowires for multifunctional applications such as flexible electronics, nanoelectromechanical systems (NEMS), and composites, a full characterization of their properties must be obtained. While many of their physical properties have been well studied, explorations of mechanical, electromechanical, and optical properties of semiconductor nanowires remain relatively sparse in the literature. Two major hurdles to the elucidation of these properties are: (1) the development of experimental techniques which are capable of mechanical and electromechanical measurements coupled with detailed structural analysis, and (2) the synthesis of high quality nanowires with the high yields necessary to produce the quantities needed for composite fabrication. These issues are addressed in this dissertation by utilizing the supercritical fluid-liquid-solid (SFLS) synthesis method to produce germanium (Ge) nanowire specimens for mechanical and electromechanical measurements coupled with high-resolution transmission electron microscopy (HRTEM). In addition, excellent dispersibility and large quantities allow for optical measurements of dispersions and composites. Ge cantilever nanoelectromechanical resonators were fabricated and induced into resonance. From the frequency response, the Young's modulus of the nanowires was determined to be insensitive to diameter and on par with the literature values for bulk Ge. The mechanical quality factors of the resonators were found to decrease with decreasing diameter. The data indicate that energy dissipation from the oscillating cantilevers occurs predominantly via surface losses. The mechanical strengths of individual Ge nanowires were measured by in situ nanomanipulation in a scanning electron microscope (SEM). The nanowires were found to tolerate diameter-dependent flexural strains more than two orders of magnitude higher than bulk Ge. Corresponding bending strengths were in agreement with the ideal strength of a perfect Ge crystal, indicative of a reduced presence of extended defects. The nanowires also exhibited plastic deformation at room temperature, becoming amorphous at the point of maximum strain. The optical absorbance spectra of Ge nanowires were measured and found to exhibit spectra markedly different from bulk Ge. Simulations using a discrete dipole approximation (DDA) model suggest that the difference in light absorption results from light trapping within the nanowires.Materials Science and Engineerin
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