3,223 research outputs found

    Homologation of the Fischer Indolization: A Quinoline Synthesis via Homo‐Diaza‐Cope Rearrangement

    Get PDF
    We disclose a new Brønsted acid promoted quinoline synthesis, proceeding via homo‐diaza‐Cope rearrangement of N‐aryl‐N′‐cyclopropyl hydrazines. Our strategy can be considered a homologation of Fischer's classical indole synthesis and delivers 6‐membered N‐heterocycles, including previously inaccessible pyridine derivatives. This approach can also be used as a pyridannulation methodology toward constructing polycyclic polyheteroaromatics. A computational analysis has been employed to probe plausible activation modes and to interrogate the role of the catalyst

    Reasoning with comparative moral judgements: an argument for Moral Bayesianism

    Get PDF
    The paper discusses the notion of reasoning with comparative moral judgements (i.e judgements of the form “act a is morally superior to act b”) from the point of view of several meta-ethical positions. Using a simple formal result, it is argued that only a version of moral cognitivism that is committed to the claim that moral beliefs come in degrees can give a normatively plausible account of such reasoning. Some implications of accepting such a version of moral cognitivism are discussed

    Propiedades físicas de sebo de cordero

    Get PDF
    The physical properties of mutton tallows isolated from the kidney, back and intestinal regions were determined by pulsed nuclear magnetic resonance and Mett ler dropping point techniques. Kidney fat showed the highest amounts of solid fat measured over a temperature range of 10-50 ºC followed by intestinal fat and back fat showed the least amount of solid fat. Mutton tallows contain 52-64% saturated acids, have iodine values ranging from 34-44 and contain small amounts (3-4%) of trans fatty acids.Se han determinado las propiedades físicas de sebo de cordero aislado de riñones, lomo e intestino mediante resonancia magnética nuclear de pulso y técnicas de punto de deslizamiento. La grasa de riñón mostró los mayores contenidos de grasa sólida medida en un rango de temperatura de 10-50 ºC seguido por la grasa del intestino y siendo la grasa del lomo la que tuvo el contenido más bajo de grasa sólida. El sebo de cordero contiene ácidos grasos saturados en proporción del 52-64%, índice de yodo que oscilan entre 34-44 y cantidades pequeñas de ácidos grasos trans (3-4%)

    Phases and geometry of the N=1 A_2 quiver gauge theory and matrix models

    Full text link
    We study the phases and geometry of the N=1 A_2 quiver gauge theory using matrix models and a generalized Konishi anomaly. We consider the theory both in the Coulomb and Higgs phases. Solving the anomaly equations, we find that a meromorphic one-form sigma(z)dz is naturally defined on the curve Sigma associated to the theory. Using the Dijkgraaf-Vafa conjecture, we evaluate the effective low-energy superpotential and demonstrate that its equations of motion can be translated into a geometric property of Sigma: sigma(z)dz has integer periods around all compact cycles. This ensures that there exists on Sigma a meromorphic function whose logarithm sigma(z)dz is the differential. We argue that the surface determined by this function is the N=2 Seiberg-Witten curve of the theory.Comment: 41 pages, 2 figures, JHEP style. v2: references adde

    Ricci Solitons and Einstein-Scalar Field Theory

    Full text link
    B List has recently studied a geometric flow whose fixed points correspond to static Ricci flat spacetimes. It is now known that this flow is in fact Ricci flow modulo pullback by a certain diffeomorphism. We use this observation to associate to each static Ricci flat spacetime a local Ricci soliton in one higher dimension. As well, solutions of Euclidean-signature Einstein gravity coupled to a free massless scalar field with nonzero cosmological constant are associated to shrinking or expanding Ricci solitons. We exhibit examples, including an explicit family of complete expanding solitons which can be thought of as a Ricci flow for a complete Lorentzian metric. The possible generalization to Ricci-flat stationary metrics leads us to consider an alternative to Ricci flow.Comment: 17 pages, 1 figure; Revised version (organizational changes, other minor revisions and corrections, citations corrected and added), to appear in CQ

    Propiedades de fusión de algunos lípidos estructurados procedentes del aceite de soja con alto contenido en ácido esteárico

    Get PDF
    A number of structured lipids native to high stearic acid soybean oil were synthesized and their physical properties were determined by pulsed nuclear magnetic resonance (NMR), Mettler dropping point and differential scanning calorimetry (DSC). 1,3 Distearo-2-olein (SOS), 1,3 distearo-2-linolein (SLS) and1,3 distearo-2-linolenin (SlnS) were synthesized from pure 1,3 diacylglycerols and the appropriate fatty acid. Pulsed NMR determinations over the temperature range 10-50 ºC showed that the symmetrical triacylglycerols (SUS: where S = stearic, U = oleic, linoleic or linolenic) are high and sharply melting materials, all showing substantial amounts of solids at temperatures up to 33.3 ºC, yet are completely melted at only a few degrees higher. Mettler dropping points for SOS, SLS and SlnS were 44.1, 37.9 and 36.5 ºC respectively. The heats of fusion for the structured triacylglycerols were determined by DSC and shown to be of the order 29-32 cal/gm compared to 45 cal/gm for SSS. The heats of fusion were also calculated from Mettler dropping point determinations as admixtures with soybean oil and showed consistent agreement with the DSC data.Se sintetizaron algunos lípidos estructurados procedentes del aceite de soja con alto contenido en ácido esteárico y sus propiedades físicas se determinaron por resonancia magnética nuclear pulsada (NMR), punto de goteo Mettler y calorimetría diferencial de barrido (DSC). Se sintetizaron 1,3 diestearo-2-oleina (SOS), 1,3 diestearo-2-linoleina (SLS) y 1,3 diestearo-2-linolenina (SlnS) a partir de 1,3 diacilgliceroles y de los ácidos grasos adecuados puros. Las determinaciones de NMR pulsada en el rango de temperaturas 10- 50 ºC mostraron que los triacilgliceroles simétricos (SUS: donde S = esteárico, U = oleico, linoleico o linolénico) funden a mayor temperatura y más bruscamente, todos presentan altos contenidos en sólidos a todas las temperaturas hasta los 33.3 ºC, estando completamente fundidos a sólo unos pocos grados por encima. Los puntos fusión Mettler de SOS, SLS y SlnS fueron 44.1, 37.9 y 36.5 ºC respectivamente. Los calores de fusión de los triacilgliceroles estructurados determinados por DSC resultaron del orden de 29-32 cal/gm frente a 45 cal/gm del SSS. Se calcularon los calores de fusión también mediante las determinaciones de los puntos de goteo Mettler como mezclas con aceite de soja y mostraron una buena concordancia con los datos DSC

    Large and Almost Maximal Neutrino Mixing within the Type II See-Saw Mechanism

    Get PDF
    Within the type II see-saw mechanism the light neutrino mass matrix is given by a sum of a direct (or triplet) mass term and the conventional (type I) see-saw term. Both versions of the see-saw mechanism explain naturally small neutrino masses, but the type II scenario offers interesting additional possibilities to explain large or almost maximal or vanishing mixings which are discussed in this paper. We first introduce ``type II enhancement'' of neutrino mixing, where moderate cancellations between the two terms can lead to large neutrino mixing even if all individual mass matrices and terms generate small mixing. However, nearly maximal or vanishing mixings are not naturally explained in this way, unless there is a certain initial structure (symmetry) which enforces certain elements of the matrices to be identical or related in a special way. We therefore assume that the leading structure of the neutrino mass matrix is the triplet term and corresponds to zero U_{e3} and maximal theta_{23}. Small but necessary corrections are generated by the conventional see-saw term. Then we assume that one of the two terms corresponds to an extreme mixing scenario, such as bimaximal or tri-bimaximal mixing. Deviations from this scheme are introduced by the second term. One can mimic Quark-Lepton Complementarity in this way. Finally, we note that the neutrino mass matrix for tri-bimaximal mixing can be -- depending on the mass hierarchy -- written as a sum of two terms with simple structure. Their origin could be the two terms of type II see-saw.Comment: 25 pages. Comments and references added, to appear in JHE

    Judgment Aggregation with Abstentions under Voters' Hierarchy

    Get PDF
    International audienceSimilar to Arrow’s impossibility theorem for preference aggregation, judgment aggregation has also an intrinsic impossibility for generating consistent group judgment from individual judgments. Removing some of the pre-assumed conditions would mitigate the problem but may still lead to too restrictive solutions. It was proved that if completeness is removed but other plausible conditions are kept, the only possible aggregation functions are oligarchic, which means that the group judgment is purely determined by a certain subset of participating judges. Instead of further challenging the other conditions, this paper investigates how the judgment from each individual judge affects the group judgment in an oligarchic environment. We explore a set of intuitively demanded conditions under abstentions and design a feasible judgment aggregation rule based on the agents’ hierarchy. We show this proposed aggregation rule satisfies the desirable conditions. More importantly, this rule is oligarchic with respect to a subset of agenda instead of the whole agenda due to its literal-based characteristics
    corecore