1,726 research outputs found

    The Glyphosate Controversy: How Vermont Perspectives Could Inform Future Policy

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    Glyphosate is the most widely used herbicide in the world and remains the main active ingredient in Monsanto’s product Roundup. Not only is glyphosate used for agricultural production, including Roundup-Ready crops, it is also used in many other day-to-day applications outside of agriculture, including lawn-care maintenance. Though there are policies set in place by the EPA, different studies conducted by national and international agencies show that this herbicide poses significant health risks to humans and the broader environment. Grounded in the concepts of risk perception, and 90 survey responses from a door-to-door survey, this study investigates the public perceptions on pesticide use in Franklin County, Vermont and makes future policy-recommendations surrounding glyphosate usage in the State of Vermont. The study finds that citizens are rarely involved in chemical regulations; studies on risk perceptions and risk analysis can be resourceful in future policy-making

    The Cosmic Lens All-Sky Survey parent population - I. Sample selection and number counts

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    We present the selection of the Jodrell Bank Flat-spectrum (JBF) radio source sample, which is designed to reduce the uncertainties in the Cosmic Lens All-Sky Survey (CLASS) gravitational lensing statistics arising from the lack of knowledge about the parent population luminosity function. From observations at 4.86 GHz with the Very Large Array, we have selected a sample of 117 flat-spectrum radio sources with flux densities greater than 5 mJy. These sources were selected in a similar manner to the CLASS complete sample and are therefore representative of the parent population at low flux densities. The vast majority (~90 per cent) of the JBF sample are found to be compact on the arcsecond scales probed here and show little evidence of any extended radio jet emission. Using the JBF and CLASS complete samples we find the differential number counts slope of the parent population above and below the CLASS 30 mJy flux density limit to be -2.07+/-0.02 and -1.96+/-0.12, respectively.Comment: 10 pages, 4 figures, accepted for publication in MNRA

    Poly-MTO, {(CH_3)_{0.92} Re O_3}_\infty, a Conducting Two-Dimensional Organometallic Oxide

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    Polymeric methyltrioxorhenium, {(CH_{3})_{0.92}ReO_{3}}_{\infty} (poly-MTO), is the first member of a new class of organometallic hybrids which adopts the structural pattern and physical properties of classical perovskites in two dimensions (2D). We demonstrate how the electronic structure of poly-MTO can be tailored by intercalation of organic donor molecules, such as tetrathiafulvalene (TTF) or bis-(ethylendithio)-tetrathiafulvalene (BEDT-TTF), and by the inorganic acceptor SbF3_3. Integration of donor molecules leads to a more insulating behavior of poly-MTO, whereas SbF3_3 insertion does not cause any significant change in the resistivity. The resistivity data of pure poly-MTO is remarkably well described by a two-dimensional electron system. Below 38 K an unusual resistivity behavior, similar to that found in doped cuprates, is observed: The resistivity initially increases approximately as ρ\rho \sim ln(1/T(1/T) before it changes into a T\sqrt{T} dependence below 2 K. As an explanation we suggest a crossover from purely two-dimensional charge-carrier diffusion within the \{ReO2_2\}_{\infty} planes at high temperatures to three-dimensional diffusion at low temperatures in a disorder-enhanced electron-electron interaction scenario (Altshuler-Aronov correction). Furthermore, a linear positive magnetoresistance was found in the insulating regime, which is caused by spatial localization of itinerant electrons at some of the Re atoms, which formally adopt a 5d15d^1 electronic configuration. X-ray diffraction, IR- and ESR-studies, temperature dependent magnetization and specific heat measurements in various magnetic fields suggest that the electronic structure of poly-MTO can safely be approximated by a purely 2D conductor.Comment: 15 pages, 16 figures, 2 table

    Supply Risk Considerations for the Elements in Nickel-Based Superalloys

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    Nickel-based superalloys contain various elements which are added in order to make the alloys more resistant to thermal and mechanical stress and to the adverse operating environments in jet engines. In particular, higher combustion temperatures in the gas turbine are important, since they result in higher fuel efficiency and thus in lower CO2 emissions. In this paper, a semi-quantitative assessment scheme is used to evaluate the relative supply risks associated with elements contained in various Ni-based superalloys: aluminium, titanium, chromium, iron, cobalt, niobium, molybdenum, ruthenium, tantalum, tungsten, and rhenium. Twelve indicators on the elemental level and four aggregation methods are applied in order to obtain the supply risk at the alloy level. The supply risks for the elements rhenium, molybdenum and cobalt are found to be the highest. For three of the aggregation schemes, the spread in supply risk values for the different alloy types (as characterized by chemical composition and the endurance temperature) is generally narrow. The fourth, namely the cost-share’ aggregation scheme, gives rise to a broader distribution of supply risk values. This is mainly due to the introduction of rhenium as a component starting with second-generation single crystal alloys. The resulting higher supply risk appears, however, to be acceptable for jet engine applications due to the higher temperatures these alloys can endur

    Lensing galaxies: light or dark?

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    In a recent paper, Hawkins (1997) argues on the basis of statistical studies of double-image gravitational lenses and lens candidates that a large population of dark lenses exists and that these outnumber galaxies with more normal mass-to-light ratios by a factor of 3:1. If correct, this is a very important result for many areas of astronomy including galaxy formation and cosmology. In this paper we discuss our new radio-selected gravitational lens sample, JVAS/CLASS, in order to test and constrain this proposition. We have obtained ground-based and HST images of all multiple-image lens systems in our sample and in 12 cases out of 12 we find the lensing galaxies in the optical and/or near infrared. Our success in finding lensing galaxies creates problems for the dark lens hypothesis. If it is to survive, ad hoc modifications seem to be necessary: only very massive galaxies (more than about one trillion solar masses) can be dark, and the cutoff in mass must be sharp. Our finding of lens galaxies in all the JVAS/CLASS systems is complementary evidence which supports the conclusion of Kochanek et al. (1997) that many of the wide-separation optically-selected pairs are physically distinct quasars rather than gravitational lens systems.Comment: 4 pages, 2 included figures, accepted for publication in Astronomy and Astrophysics. Paper version available on request. This replacement amends the text to allow more discussion of the overlap with astro-ph/971016

    MEVA - An interactive visualization application for validation of multifaceted meteorological data with multiple 3D devices

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    To achieve more realistic simulations, meteorologists develop and use models with increasing spatial and temporal resolution. The analyzing, comparing, and visualizing of resulting simulations becomes more and more challenging due to the growing amounts and multifaceted character of the data. Various data sources, numerous variables and multiple simulations lead to a complex database. Although a variety of software exists suited for the visualization of meteorological data, none of them fulfills all of the typical domain-specific requirements: support for quasi-standard data formats and different grid types, standard visualization techniques for scalar and vector data, visualization of the context (e.g., topography) and other static data, support for multiple presentation devices used in modern sciences (e.g., virtual reality), a user-friendly interface, and suitability for cooperative work

    Global Metal Use Targets in Line with Climate Goals.

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    Metals underpin essential functions in modern society, yet their production currently intensifies climate change. This paper develops global targets for metal flows, stocks, and use intensity in the global economy out to 2100. These targets are consistent with emissions pathways to achieve a 2 °C climate goal and cover six major metals (iron, aluminum, copper, zinc, lead, and nickel). Results indicate that despite advances in low-carbon metal production, a transformative system change to meet the society's needs with less metal is required to remain within a 2 °C pathway. Globally, demand for goods and services over the 21st century needs to be met with approximately 7 t/capita of metal stock-roughly half the current level in high-income countries. This systemic change will require a peak in global metal production by 2030 and deep decoupling of economic growth from both metal flows and stocks. Importantly, the identified science-based targets are theoretically achievable through such measures as efficient design, more intensive use, and longer product lifetime, but immediate action is crucial before middle- and low-income countries complete full-scale urbanization

    Effect of Conventional Mouthrinses on Initial Bioadhesion to Enamel and Dentin in situ

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    Aim: The study aimed to investigate the effect of a customary fluoride solution, containing sodium fluoride and amine fluoride, on initial biofilm formation on enamel and dentin in situ compared directly to chlorhexidine. Methods: Bovine enamel and dentin specimens were mounted on maxillary splints carried by 9 subjects. After 1 min of pellicle formation, rinses with tap water (control), chlorhexidine (meridol med CHX 0.2%, GABA) and a fluoride mouthrinse (elmex, GABA) were performed for 1 min. Subsequently, the slabs were carried for another 8 h. The adherent bacteria were determined by DAPI staining, live-dead staining and determination of colony-forming units after desorption; glucan formation was visualized with concanavalin A. Additionally, energy-dispersive X-ray spectroscopy (EDX) analysis of the in situ biofilm layers was conducted, and contact angle measurements were performed. Statistical evaluation was performed by means of the Kruskal-Wallis test followed by the Mann-Whitney U test (p < 0.05). Results: In the control group, significantly higher amounts of adherent bacteria were detected on dentin (4.8 x 10⁶ ± 5.4 x 10⁶ bacteria/cm²) than on enamel (1.2 x 10⁶ ± 1.5 x 10⁶ bacteria/cm² , DAPI). Chlorhexidine significantly reduced the amount of adherent bacteria (dentin: 2.8 x 10⁵ ± 3.4 x 10⁵ bacteria/cm² ; enamel: 4.2 x 10⁵ ± 8.7 x 10⁵ bacteria/cm²). Rinses with the fluoride solution also significantly reduced bacterial adherence to dentin (8.1 x 10⁵ ± 1.5 x 10⁶ bacteria/cm²). Fluoride could not be detected by EDX analysis of the biofilms. Fluoride mouthrinsing did not influence the wettability of the pellicle-covered enamel surface. Conclusion: In addition to the reduction of demineralization and antibacterial effects, fluorides inhibit initial biofilm formation on dental hard tissues considerably, especially on dentin

    An Evaluation of a Teaching Interaction Procedure Implemented in a Recess Setting

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    The teaching interaction procedure (TIP) is a strategy that has been demonstrated as effective in promoting social skill acquisition in school settings for young students with social communication deficits (Leaf et al., 2009; Leaf et al., 2010). However, a frequently cited criticism of social skills training is the lack of generalizability of target skills to novel contexts (Bellini et al., 2007). The purpose of the study was to evaluate a TIP-based social skills intervention conducted on the playground, intended to promote generalizability through training in naturalistic settings and to evaluate generalizability of skill acquisition to the classroom. Eight students 5-8 years old with an educational classification of autism or developmental delay participated in the study. The primary dependent variable was skill acquisition in the playground setting, and a secondary measure was generalized skill acquisition to the classroom setting. Target skills included appropriate body language, participation, and responding to initiations. A multi-probe design embedded within a multiple baseline design across target skills with concurrent replication across participants was used to evaluate the primary and secondary measures. Overall, results suggest that increases in skill acquisition were observed during implementation of the TIP across most participants and skills in both training and generalization phases. However, substantial variability was noted across participants related to maintaining skill acquisition during maintenance and follow-up phases in both the training and generalization settings. Limitations of these results are discussed as well as implications for school practitioners
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