1,354 research outputs found

    Optically Active Coordination Compounds. Part 50. 4-Fold Symmetry Axes in Optically Active Complex Ions from Natural Nicotine

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    The synthesis, characterization and circular dichroism under varied conditions (notably pR) of trans-dichloro-tetrakis-(S)-(-)- nicotiniumrhodium(III) salts are described, to illustrate the interplay of chirality of the metal ion (D4) and at carbon centres (C1)

    Universal Wellbeing Practices in Schools: Framing Evidence-Informed Practice Within the Five Ways to Wellbeing

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    In 2017, the UK Government published Transforming Children and Young People’s Mental Health Provision: A Green Paper (Department for Education & Department of Health, 2017), making clear that their intention is to place schools at the forefront of a national strategy to improve the mental wellbeing of children. The Special Educational Needs and Disability Code of Practice (SEND CoP; Department for Education & Department of Health, 2015) includes Social, Emotional and Mental Health as one primary area of SEND, emphasising a graduated approach to intervention, beginning with high-quality teaching. Taken together, the clear implication is that schools should arrange provision to promote children’s wellbeing at the universal level, not just at the targeted and specialist levels. With its emphasis upon evidence-based actions, the New Economics Foundation’s (NEF’s) Five Ways to Wellbeing (Aked et al., 2008) is proposed here as a framework for organising provisions. Relevant evidence-based programs, as well as strategies and procedures, are presented, each of which is universally applicable, relevant across primary and secondary phases, and linked to the NEF’s Five Ways

    Self-interacting Elko dark matter with an axis of locality

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    This communication is a natural and nontrivial continuation of the 2005 work of Ahluwalia and Grumiller on Elko. Here we report that Elko breaks Lorentz symmetry in a rather subtle and unexpected way by containing a `hidden' preferred direction. Along this preferred direction, a quantum field based on Elko enjoys locality. In the form reported here, Elko offers a mass dimension one fermionic dark matter with a quartic self-interaction and a preferred axis of locality. The locality result crucially depends on a judicious choice of phases.Comment: 14 pages (RevTex

    Vanishing Preons in the Fifth Dimension

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    We examine supersymmetric solutions of N=2, D=5 gauged supergravity coupled to an arbitrary number of abelian vector multiplets using the spinorial geometry method. By making use of methods developed in hep-th/0606049 to analyse preons in type IIB supergravity, we show that there are no solutions preserving exactly 3/4 of the supersymmetry.Comment: 19 pages, latex. Reference added, and further modification to the introductio

    The Impact of Phase Equilibrium Cloud Models on GCM Simulations of GJ~1214b

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    We investigate the impact of clouds on the atmosphere of GJ~1214b using the radiatively-coupled, phase-equilibrium cloud model {\sc EddySed} coupled to the {\sc Unified Model} general circulation model. We find that, consistent with previous investigations, high metallicity (100×100\times solar) and clouds with large vertical extents (a sedimentation factor of fsed=0.1f_\mathrm{sed} = 0.1) are required to best match the observations, although metallicities even higher than those investigated here may be required to improve agreement further. We additionally find that in our case which best matches the observations (fsed=0.1f_\mathrm{sed}=0.1), the velocity structures change relative to the clear sky case with the formation of a superrotating jet being suppressed, although further investigation is required to understand the cause of the suppression. The increase in cloud extent with fsedf_\mathrm{sed} results in a cooler planet due to a higher albedo, causing the atmosphere to contract. This also results in a reduced day-night contrast seen in the phase curves, although the introduction of cloud still results in a reduction of the phase offset. We additionally investigate the impact the the {\sc Unified Model}'s pseudo-spherical irradiation scheme on the calculation of heating rates, finding that the introduction of nightside shortwave heating results in slower mid-latitude jets compared to the plane parallel irradiation scheme used in previous works. We also consider the impact of a gamma distribution, as opposed to a log-normal distribution, for the distribution of cloud particle radii and find the impact to be relatively minor.Comment: Accepted to MNRA

    The spinorial geometry of supersymmetric heterotic string backgrounds

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    We determine the geometry of supersymmetric heterotic string backgrounds for which all parallel spinors with respect to the connection ^\hat\nabla with torsion HH, the NS\otimesNS three-form field strength, are Killing. We find that there are two classes of such backgrounds, the null and the timelike. The Killing spinors of the null backgrounds have stability subgroups K\ltimes\bR^8 in Spin(9,1)Spin(9,1), for K=Spin(7)K=Spin(7), SU(4), Sp(2)Sp(2), SU(2)×SU(2)SU(2)\times SU(2) and {1}\{1\}, and the Killing spinors of the timelike backgrounds have stability subgroups G2G_2, SU(3), SU(2) and {1}\{1\}. The former admit a single null ^\hat\nabla-parallel vector field while the latter admit a timelike and two, three, five and nine spacelike ^\hat\nabla-parallel vector fields, respectively. The spacetime of the null backgrounds is a Lorentzian two-parameter family of Riemannian manifolds BB with skew-symmetric torsion. If the rotation of the null vector field vanishes, the holonomy of the connection with torsion of BB is contained in KK. The spacetime of time-like backgrounds is a principal bundle PP with fibre a Lorentzian Lie group and base space a suitable Riemannian manifold with skew-symmetric torsion. The principal bundle is equipped with a connection λ\lambda which determines the non-horizontal part of the spacetime metric and of HH. The curvature of λ\lambda takes values in an appropriate Lie algebra constructed from that of KK. In addition dHdH has only horizontal components and contains the Pontrjagin class of PP. We have computed in all cases the Killing spinor bilinears, expressed the fluxes in terms of the geometry and determine the field equations that are implied by the Killing spinor equations.Comment: 73pp. v2: minor change

    Supersymmetric gyratons in five dimensions

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    We obtain the gravitational and electromagnetic field of a spinning radiation beam-pulse (a gyraton) in minimal five-dimensional gauged supergravity and show under which conditions the solution preserves part of the supersymmetry. The configurations represent generalizations of Lobatchevski waves on AdS with nonzero angular momentum, and possess a Siklos-Virasoro reparametrization invariance. We compute the holographic stress-energy tensor of the solutions and show that it transforms without anomaly under these reparametrizations. Furthermore, we present supersymmetric gyratons both in gauged and ungauged five-dimensional supergravity coupled to an arbitrary number of vector supermultiplets, which include gyratons on domain walls.Comment: 25 pages, no figures, uses JHEP3.cls. Final version to appear in CQ

    Spinorial geometry and Killing spinor equations of 6-D supergravity

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    We solve the Killing spinor equations of 6-dimensional (1,0)-supergravity coupled to any number of tensor, vector and scalar multiplets in all cases. The isotropy groups of Killing spinors are Sp(1)\cdot Sp(1)\ltimes \bH (1), U(1)\cdot Sp(1)\ltimes \bH (2), Sp(1)\ltimes \bH (3,4), Sp(1)(2)Sp(1) (2), U(1)(4)U(1) (4) and {1}(8)\{1\} (8), where in parenthesis is the number of supersymmetries preserved in each case. If the isotropy group is non-compact, the spacetime admits a parallel null 1-form with respect to a connection with torsion the 3-form field strength of the gravitational multiplet. The associated vector field is Killing and the 3-form is determined in terms of the geometry of spacetime. The Sp(1)\ltimes \bH case admits a descendant solution preserving 3 out of 4 supersymmetries due to the hyperini Killing spinor equation. If the isotropy group is compact, the spacetime admits a natural frame constructed from 1-form spinor bi-linears. In the Sp(1)Sp(1) and U(1) cases, the spacetime admits 3 and 4 parallel 1-forms with respect to the connection with torsion, respectively. The associated vector fields are Killing and under some additional restrictions the spacetime is a principal bundle with fibre a Lorentzian Lie group. The conditions imposed by the Killing spinor equations on all other fields are also determined.Comment: 34 pages, Minor change
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