4,611 research outputs found

    Inheritance and yield with particular reference to rust resistance and panicle type in oats

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    This archival publication may not reflect current scientific knowledge or recommendations

    Liquidus Phases of the Richardson H5 Chondrite at High Pressures and Temperatures

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    Part of early mantle evolution may include a magma ocean, where core formation began before the proto-Earth reached half of its present radius. Temperatures were high and bombardment and accretion were still occurring, suggesting that the proto-Earth consisted of a core and an at least partially liquid mantle, the magma ocean. As the Earth accreted, pressure near the core increased and the magma ocean decreased in volume and became shallower as it began to cool and solidify. As crystals settled, or floated, the composition of the magma ocean could change significantly and begin to crystallize different minerals from the residual liquid. Therefore, the mantle may be stratified following the P-T phase diagram for the bulk silicate Earth. To understand mantle evolution, it is necessary to know liquidus phase relations at high pressures and temperatures. In order to model the evolution of the magma ocean, high pressure and temperature experiments have been conducted to simulate the crystallization process using a range of materials that most likely resemble the bulk composition of the early Earth

    Characterization of Glycated Proteins by \u3csup\u3e13\u3c/sup\u3eC NMR Spectroscopy

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    13C NMR spectroscopy has been used to characterize Amadori (ketoamine) adducts formed by reaction of [2-13C]glucose with free amino groups of protein. The spectra of glycated proteins were acquired in phosphate buffer at pH 7.4 and were interpreted by reference to the spectra of model compounds, N alpha-formyl-N epsilon-fructose-lysine and glycated poly-L-lysine (GlcPLL). The anomeric carbon region of the spectrum (approximately 90-105 ppm) of glycated cytochrome c was superimposable on that of N alpha-formyl-N epsilon-fructose-lysine, and contained three peaks characteristic of the alpha- and beta-furanose and beta-pyranose anomers of Amadori adducts to peripheral lysine residues on protein (pK alpha approximately 10.5). The spectrum of GlcPLL yielded six anomeric carbon resonances; the second set of three was displaced about 2 ppm to lower shielding of the first and was assigned to the Amadori adduct at the alpha-amino terminus (pK alpha approximately 7.5). The spectrum of glycated RNase was similar to that of GlcPLL, but contained a third set of three signals attributable to modification of active site lysine 41 (pK alpha approximately 8.8). The assignments for RNase were confirmed by analysis of spectra taken at pH 4 and under denaturing conditions. The spectrum of glycated hemoglobin was comparable to that of GlcPLL, and distinct resonances could be assigned to Amadori adducts at amino-terminal valine and intrachain N epsilon-lysine residues. Chemical analyses were performed to measure the relative extent of alpha- and epsilon-amino group modification in the glycated macromolecules, and the results were compared with estimates based on integration of the NMR spectra

    Linguistic incompetence: giving an account of researching multilingually

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    This paper considers the place of linguistic competence and incompetence in the context of researching multilingually. It offers a critique of the concept of competence and explores the performative dimensions of multilingual research and its narration, through the philosophy of Judith Butler, and in particular her study Giving an account of oneself. It explores aspects of risk, justice, narrative limit and a morality of multilingualism in emergent multilingual research frameworks. These theoretical dimensions are explored through consideration of ‘linguistically incompetent’ ethnographic work with refugees and asylum seekers, in contexts of hospitality and in life long learning research in the Gaza Strip, and of early attempts to learn new languages. The paper offers a prospect of a relational approach to researching multilingually and affirms the vulnerability at the heart of linguistic hospitality

    How to Reduce Tire-Pavement Noise: Interim Better Practices for Constructing and Texturing Concrete Pavement Surfaces

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    This report describes better practices for constructing and texturing quieter concrete pavements; better practices that answer the question of how we can reduce tire-pavement noise; and better practices that don\u27t compromise the other things about the pavement that are of equal or greater importance, including safety, cost, and durability. In developing this document, the National Concrete Pavement Technology Center at Iowa State University draws from its decades of combined experience working for and alongside concrete paving contractors. This document also includes the collective experience of various contractors and equipment manufacturers with a reputation for quality. These guidelines further address the challenges that are faced in consistently producing a high-quality product in a low-bid environment. This document is intended to serve as interim guidelines and better practices for texturing. Work under the pooled fund study that sponsored the development of this document is ongoing. Additional data are being collected on both existing and new concrete paving projects that will validate the practices described herein. Given the importance of this issue, however, it is believed that many of these practices can be implemented immediately without adverse consequences. Refinements to these practices can then be implemented as necessary as changes to these better practices are made in the near future

    Evaluating the effects of bilingual traffic signs on driver performance and safety

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    Variable Message Signs (VMS) can provide immediate and relevant information to road users and bilingual VMS can provide great flexibility in countries where a significant proportion of the population speak an alternative language to the majority. The study reported here evaluates the effect of various bilingual VMS configurations on driver behaviour and safety. The aim of the study was to determine whether or not the visual distraction associated with bilingual VMS signs of different configurations (length, complexity) impacted on driving performance. A driving simulator was used to allow full control over the scenarios, road environment and sign configuration and both longitudinal and lateral driver performance was assessed. Drivers were able to read one and two-line monolingual signs and two-line bilingual signs without disruption to their driving behaviour. However, drivers significantly reduced their speed in order to read four-line monolingual and four-line bilingual signs, accompanied by an increase in headway to the vehicle in front. This implies that drivers are possibly reading the irrelevant text on the bilingual sign and various methods for reducing this effect are discussed

    \u3csup\u3e13\u3c/sup\u3eC NMR Investigation of Nonenzymatic Glucosylation of Protein

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    Nonenzymatic glucosylation of protein is initiated by the reversible condensation of glucose in its open chain form with the amino groups on the protein. The initial product is an aldimine (Schiff base) which cyclizes to the glycosylamine derivative. The aldimine can undergo a slow Amadori rearrangement to yield the relatively stable ketoamine adduct which is structurally analogous to fructose. 13C NMR has been used to characterize these early products of nonenzymatic glucosylation, using RNase A as a model protein. C-1 of the beta-pyranose anomer of the glycosylamine was identified at 88.8 ppm in the spectrum of RNase glucosylated approximately 1:1 with D-[1-13C]glucose. C-1 of the Amadori product was also apparent in this spectrum, resonating as a pair of intense peaks at 52.7 and 53.1 ppm. The anomeric (C-2) resonances of the Amadori adduct were seen in the spectrum of RNase glucosylated approximately 1:1 with [U-13C]glucose. This spectrum was interpreted by comparison to the spectra of reference compounds: D-fructose, fructose-glycine, N alpha-formyl-N epsilon-fructose-lysine, and glucosylated poly-L-lysine. In the protein spectrum, the most intense of the C-2 resonances was that of the beta-fructopyranose anomer at 95.8 ppm. The alpha- and beta-fructofuranose anomers were also observed at 101.7 and 99.2 ppm, respectively. One unidentified signal in the anomeric region was observed in the spectra of poly-L-lysine and RNase, both glucosylated with [U-13C]glucose; no comparable resonances were observed in the spectra of the model compounds

    The evolution of interdependence in a four-way mealybug symbiosis

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    Mealybugs are insects that maintain intracellular bacterial symbionts to supplement their nutrientpoor plant sap diets. Some mealybugs have a single betaproteobacterial endosymbiont, a Candidatus Tremblaya species (hereafter Tremblaya) that alone provides the insect with its required nutrients. Other mealybugs have two nutritional endosymbionts that together provide these nutrients, where Tremblaya has gained a gammaproteobacterial partner that resides in the cytoplasm of Tremblaya. Previous work had established that Pseudococcus longispinus mealybugs maintain not one but two species of gammaproteobacterial endosymbionts along with Tremblaya. Preliminary genomic analyses suggested that these two gammaproteobacterial endosymbionts have large genomes with features consistent with a relatively recent origin as insect endosymbionts, but the patterns of genomic complementarity between members of the symbiosis and their relative cellular locations were unknown. Here, using long-read sequencing and various types of microscopy, we show that the two gammaproteobacterial symbionts of P. longispinus are mixed together within Tremblaya cells, and that their genomes are somewhat reduced in size compared to their closest non-endosymbiotic relatives. Both gammaproteobacterial genomes contain thousands of pseudogenes, consistent with a relatively recent shift from a free-living to endosymbiotic lifestyle. Biosynthetic pathways of key metabolites are partitioned in complex interdependent patterns among the two gammaproteobacterial genomes, the Tremblaya genome, and horizontally acquired bacterial genes that are encoded on the mealybug nuclear genome. Although these two gammaproteobacterial endosymbionts have been acquired recently in evolutionary time, they have already evolved co-dependencies with each other, Tremblaya, and their insect host

    Teleology and Realism in Leibniz's Philosophy of Science

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    This paper argues for an interpretation of Leibniz’s claim that physics requires both mechanical and teleological principles as a view regarding the interpretation of physical theories. Granting that Leibniz’s fundamental ontology remains non-physical, or mentalistic, it argues that teleological principles nevertheless ground a realist commitment about mechanical descriptions of phenomena. The empirical results of the new sciences, according to Leibniz, have genuine truth conditions: there is a fact of the matter about the regularities observed in experience. Taking this stance, however, requires bringing non-empirical reasons to bear upon mechanical causal claims. This paper first evaluates extant interpretations of Leibniz’s thesis that there are two realms in physics as describing parallel, self-sufficient sets of laws. It then examines Leibniz’s use of teleological principles to interpret scientific results in the context of his interventions in debates in seventeenth-century kinematic theory, and in the teaching of Copernicanism. Leibniz’s use of the principle of continuity and the principle of simplicity, for instance, reveal an underlying commitment to the truth-aptness, or approximate truth-aptness, of the new natural sciences. The paper concludes with a brief remark on the relation between metaphysics, theology, and physics in Leibniz

    Remarks on Causality in Relativistic Quantum Field Theory

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    It is shown that the correlations predicted by relativistic quantum field theory in locally normal states between projections in local von Neumann algebras \cA(V_1),\cA(V_2) associated with spacelike separated spacetime regions V1,V2V_1,V_2 have a (Reichenbachian) common cause located in the union of the backward light cones of V1V_1 and V2V_2. Further comments on causality and independence in quantum field theory are made.Comment: 10 pages, Latex, Quantum Structures 2002 Conference Proceedings submission. Minor revision of the order of definitions on p.
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