1,601 research outputs found

    Total Reflection and Negative Refraction of Dipole-Exchange Spin Waves at Magnetic Interfaces: Micromagnetic Modeling Study

    Get PDF
    We demonstrated that dipole-exchange spin waves traveling in geometrically restricted magnetic thin films satisfy the same laws of reflection and refraction as light waves. Moreover, we found for the first time novel wave behaviors of dipole-exchange spin waves such as total reflection and negative refraction. The total reflection in laterally inhomogeneous thin films composed of two different magnetic materials is associated with the forbidden modes of refracted dipole-exchange spin waves. The negative refraction occurs at a 90 degree domain-wall magnetic interface that is introduced by a cubic magnetic anisotropy in the media, through the anisotropic dispersion of dipole-exchange spin waves.Comment: 13 pages, 5 figure

    Role of LAB in Silage Fermentation: Effect on Nutritional Quality and Organic Acid Production—An Overview

    Get PDF
    Lactic acid bacteria (LAB) inocula play a key role in the preservation and fermentation of forage crops within inoculated silages. LAB is a significant group of the bacterial community as they successfully reduce pH, inhibit the survival of undesirable microorganisms and control nutrient loss in fermented silage. Ensiled plants and metabolites such as simple plant carbohydrates have been utilized by LAB (homo-fermentative and hetero-fermentative LAB) to initiate the production of organic acids including lactic and acetic acids. LAB as a biological silage additive provides stable feed value and secondary metabolic products during rapid anaerobic primary silage fermentation. They are able to ferment a large number of forage crops and also to reduce pH levels in fermented forages, which helps to suppress the growth of spoilage microorganisms. Furthermore, silage inoculants can enhance silage quality, nutritional recovery and shelf life of the inoculated product. When ingested silage, Lactobacilli in the rumen may degrade secondary plant metabolites as part of the rumen microbiota, along with endogenous enzymes. Also, the forages harvesting time are key factors in the development of essential metabolites particularly carbohydrates and proteins which is essential nutrition for LAB survival and production of organic acids. The higher population of LAB could reduce the pH faster and control of deleterious microbial growth in silage. This review presents LAB function in silage production and the potential impacts of its fermentative activity. In addition, the advantage of LAB additives in silage production is discussed, with a focus on recent literature

    Inelastic scattering in a monolayer graphene sheet; a weak-localization study

    Full text link
    Charge carriers in a graphene sheet, a single layer of graphite, exhibit much distinctive characteristics to those in other two-dimensional electronic systems because of their chiral nature. In this report, we focus on the observation of weak localization in a graphene sheet exfoliated from a piece of natural graphite and nano-patterned into a Hall-bar geometry. Much stronger chiral-symmetry-breaking elastic intervalley scattering in our graphene sheet restores the conventional weak localization. The resulting carrier-density and temperature dependence of the phase coherence length reveal that the electron-electron interaction including a direct Coulomb interaction is the main inelastic scattering factor while electron-hole puddles enhance the inelastic scattering near the Dirac point.Comment: 12 pages, 3 figures, submitted to PR

    Role of G{alpha}12 and G{alpha}13 as Novel Switches for the Activity of Nrf2, a Key Antioxidative Transcription Factor

    Get PDF
    G{alpha}12 and G{alpha}13 function as molecular regulators responding to extracellular stimuli. NF-E2-related factor 2 (Nrf2) is involved in a protective adaptive response to oxidative stress. This study investigated the regulation of Nrf2 by G{alpha}12 and G{alpha}13. A deficiency of G{alpha}12, but not of G{alpha}13, enhanced Nrf2 activity and target gene transactivation in embryo fibroblasts. In mice, G{alpha}12 knockout activated Nrf2 and thereby facilitated heme catabolism to bilirubin and its glucuronosyl conjugations. An oligonucleotide microarray demonstrated the transactivation of Nrf2 target genes by G{alpha}12 gene knockout. G{alpha}12 deficiency reduced Jun N-terminal protein kinase (JNK)-dependent Nrf2 ubiquitination required for proteasomal degradation, and so did G{alpha}13 deficiency. The absence of G{alpha}12, but not of G{alpha}13, increased protein kinase C {delta} (PKC {delta}) activation and the PKC {delta}-mediated serine phosphorylation of Nrf2. G{alpha}13 gene knockout or knockdown abrogated the Nrf2 phosphorylation induced by G{alpha}12 deficiency, suggesting that relief from G{alpha}12 repression leads to the G{alpha}13-mediated activation of Nrf2. Constitutive activation of G{alpha}13 promoted Nrf2 activity and target gene induction via Rho-mediated PKC {delta} activation, corroborating positive regulation by G{alpha}13. In summary, G{alpha}12 and G{alpha}13 transmit a JNK-dependent signal for Nrf2 ubiquitination, whereas G{alpha}13 regulates Rho-PKC {delta}-mediated Nrf2 phosphorylation, which is negatively balanced by G{alpha}12

    Strategic Trade Policies in International Rivalry When Competition Mode is Endogenous

    Get PDF
    We investigate government subsidy policies in which a home firm and a foreign firm choose to strategically set prices or quantities in a third market. We show that even though each firm can earn higher profits under Cournot competition than under Bertrand competition regardless of the nature of goods, choosing Bertrand competition is the dominant strategy for both firms. This can lead each firm to face a prisoners' dilemma in equilibrium. We also show that from the aspects of governments under subsidy regime, Cournot competition is more efficient than Bertrand competition when the goods are substitutes, and vice versa when the goods are complements. However, trade liberalization such as via free trade agreements brings about a change in the competition mode from Bertrand competition to Cournot competition if goods are substitutes. On the other hand, if goods are complements, there are no such a change in the competition mode and Bertrand competition prevails the market. Hence, a move toward free trade among countries increases not only profits of firms but also the welfare of both countries irrespective of the nature of goods

    Strategic Trade Policies in International Rivalry When Competition Mode is Endogenous

    Get PDF
    We investigate government subsidy policies in which a home firm and a foreign firm choose to strategically set prices or quantities in a third market. We show that even though each firm can earn higher profits under Cournot competition than under Bertrand competition regardless of the nature of goods, choosing Bertrand competition is the dominant strategy for both firms. This can lead each firm to face a prisoners' dilemma in equilibrium. We also show that from the aspects of governments under subsidy regime, Cournot competition is more efficient than Bertrand competition when the goods are substitutes, and vice versa when the goods are complements. However, trade liberalization such as via free trade agreements brings about a change in the competition mode from Bertrand competition to Cournot competition if goods are substitutes. On the other hand, if goods are complements, there are no such a change in the competition mode and Bertrand competition prevails the market. Hence, a move toward free trade among countries increases not only profits of firms but also the welfare of both countries irrespective of the nature of goods

    Noxious gas detection using carbon nanotubes with Pd nanoparticles

    Get PDF
    Noxious gas sensors were fabricated using carbon nanotubes [CNTs] with palladium nanoparticles [Pd NPs]. An increase in the resistance was observed under ammonia for both CNTs and CNT-Pd sensors. Under carbon monoxide [CO], the two sensors exhibited different behaviors: for CNT sensors, their resistance decreased slightly with CO exposure, whereas CNT-Pd sensors showed an increase in resistance. The sensing properties and effect of Pd NPs were demonstrated, and CNT-Pd sensors with good repeatability and fast responses over a range of concentrations may be used as a simple and effective noxious gas sensor at room temperature

    APPLICATION OF ULTRA-HIGH PERFORMANCE CONCRETE TO PEDESTRIAN CABLE-STAYED BRIDGES

    Get PDF
    The use of ultra-high performance concrete (UHPC), which enables reducing the cross sectional dimension of the structures due to its high strength, is expected in the construction of the super-long span bridges. Unlike conventional concrete, UHPC experiences less variation of material properties such as creep and drying shrinkage and can reduce uncertainties in predicting time-dependent behavior over the long term. This study describes UHPC’s material characteristics and benefits when applied to super-long span bridges. A UHPC girder pedestrian cable-stayed bridge was designed and successfully constructed. The UHPC reduced the deflections in both the short and long term. The cost analysis demonstrates a highly competitive price for UHPC. This study indicates that UHPC has a strong potential for application in the super-long span bridges
    corecore