188,784 research outputs found
A note on the magnitude of the flux superpotential
No full textThe magnitude of the flux superpotential W flux plays a crucial role in determining the scales of IIB string compactifications after moduli stabilisation. It has been argued that values of W flux ≠1 are preferred, and even required for physical and consistency reasons. This note revisits these arguments. We establish that the couplings of heavy Kaluza-Klein modes to light states scale with the internal volume as g ∼ M KK /M P ∼ -2/3 ≠1 and argue that consistency of the superspace derivative expansion requires gF/M 2 ∼ m 3/2 /M KK ≠1, where F is the auxiliary field of the light fields and M the ultraviolet cutoff. This gives only a mild constraint on the flux superpotential, W flux ≠1/3, which can be easily satisfied for (1) values of W flux. This regime is also statistically favoured and makes the Bousso-Polchinski mechanism for the vacuum energy hierarchically more efficient. © 2014 The Author(s)
Conformational change following conversion of inactive rhinophrynin-33 to bioactive rhinophrynin-27 in the skin of the frog Rhinophrynus dorsalis
No full textSkin secretions of the Mexican burrowing toad Rhinophrynus dorsalis (Rhinophrynidae) contain the proline-arginine-rich peptide, rhinophrynin-27 (RP-27; ELRLPEIARPVPEVLPARLPLPALPRN) with insulinotropic and immunomodulatory properties, together with a higher concentration of the biologically inactive form, rhinophrynin-33 (RP-33) that constitutes RP-27 extended from its C-terminus by the hexapeptide KMAKNQ. Determination of the conformation of RP-33 by NMR demonstrates that in both water and in a solvent that promotes protein folding (50% trifluoroethanol-water), the majority of the proline residues are found in a polyproline type II helical region. The peptide adopts a horseshoe (U-shaped) conformation with pronounced bends in the molecule of around 100°–120° at Glu13 and Arg18. The hexapeptide extension adopts a α-helical conformation. When the hexapeptide is excised to generate RP-27, the molecule adopts an L-shaped conformation with a single bend at Glu13. A search of protein sequence databases indicated the P-X-P-XXX-P-XXX-P-X-P motif found in RP-27 and RP-33 occurs in a number of proteins although its functional implications are unclear. The data suggest that RP-33 represents a biosynthetic precursor of RP-27 that is activated by a protease cleaving at a single lysine residue of the type previously identified in Xenopus laevis skin secretions
General Analysis of LARGE Volume Scenarios with String Loop Moduli Stabilisation
No full textWe study the topological conditions for general Calabi-Yaus to get a non-supersymmetric AdS exponentially large volume minimum of the scalar potential in flux compactifications of IIB string theory. We show that negative Euler number and the existence of at least one blow-up mode resolving point-like singularities are necessary and sufficient conditions for moduli stabilisation with exponentially large volumes. We also analyse the general effects of string loop corrections on this scenario. While the combination of alpha' and nonperturbative corrections are sufficient to stabilise blow-up modes and the overall volume, quantum corrections are needed to stabilise other directions transverse to the overall volume. This allows exponentially large volume minima to be realised for fibration Calabi-Yaus, with the various moduli of the fibration all being stabilised at exponentially large values. String loop corrections may also play a role in stabilising 4-cycles which support chiral matter and cannot enter directly into the non-perturbative superpotential. We illustrate these ideas by studying the scalar potential for various Calabi-Yau three-folds including K3 fibrations and briefly discuss the potential phenomenological and cosmological implications of our results
Hoboken policemen, group photo at side of building.
No full text1) D. Kiely, 2) Capt. Garrick, 3) John McKenna, 4) P. Gerhardt, 5) J. Hildeman, 6) J. Conlon, 7) O'Driscoll, 8) Delaney, 9) ???, 10) Capt. Flattony. ca. 188
In order and out of time: Compositions exploring processes, polymeters and balance
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.These compositions explore concepts based on processes and polymeter. Drawing on influences ranging from Steve Reich to Conlon Nancarrow and Nik Bärtsch they use and develop an approach to rhythmic thinking based on ostinati constructed of layers of different speeds. Through the use of click tracks, they look at how an ensemble can be enabled to perform rhythms that, without the electronic support, would be unplayable – crossing a line between the possible and the impossible. By means of processes built on a number of different ideas, the pieces explore how these can be used to affect both the behaviour and evolution of musical material, as well as using them to create fixed structures within which I then move subjectively and more intuitively. The question of balance, of moving between two points or approaches that are seemingly opposites, has also been examined: looking at how the journey affects the destination, where the simple becomes complex, and where personal meets impersonal
Pierre M. Conlon, Le siècle des Lumières. Bibliographie chronologique, tome XXIV et XXV
No full textDepuis vingt-cinq ans, volume après volume, Pierre Conlon élabore patiemment une exceptionnelle bibliographie chronologique d’un siècle des Lumières courant de 1716 à 1789. Depuis l’origine, les objectifs de l’entreprise n’ont pas varié ; il s’agit d’établir une bibliographie des publications du XVIIIe siècle qui fasse le lien entre le répertoire disponible pour les années 1680-1715 (P. Conlon, 1970-1975, 6 vol.) et les travaux bibliographiques de la Révolution et de l’Empire, des classiques ..
Systematics of String Loop Corrections in Type IIB Calabi-Yau Flux Compactifications
No full textWe study the behaviour of the string loop corrections to the N=1 4D supergravity Kaehler potential that occur in flux compactifications of IIB string theory on general Calabi-Yau three-folds. We give a low energy interpretation for the conjecture of Berg, Haack and Pajer for the form of the loop corrections to the Kaehler potential. We check the consistency of this interpretation in several examples. We show that for arbitrary Calabi-Yaus, the leading contribution of these corrections to the scalar potential is always vanishing, giving an "extended no-scale structure". This result holds as long as the corrections are homogeneous functions of degree -2 in the 2-cycle volumes. We use the Coleman-Weinberg potential to motivate this cancellation from the viewpoint of low-energy field theory. Finally we give a simple formula for the 1-loop correction to the scalar potential in terms of the tree-level Kaehler metric and the correction to the Kaehler potential. We illustrate our ideas with several examples. A companion paper will use these results in the study of Kaehler moduli stabilisation
Pierre M. Conlon : Le Siècle des Lumières. Bibliographie chronologique. Tome XXI : 1784-1785, 2001
No full textDesné Roland. Pierre M. Conlon : Le Siècle des Lumières. Bibliographie chronologique. Tome XXI : 1784-1785, 2001. In: Dix-huitième Siècle, n°34, 2002. Christianisme et Lumières, sous la direction de Sylviane Albertan-Coppola et Antony McKenna. p. 558
Moduli-Induced Vacuum Destabilisation
No full textWe look for ways to destabilise the vacuum. We describe how dense matter environments source a contribution to moduli potentials and analyse the conditions required to initiate either decompactification or a local shift in moduli vevs. We consider astrophysical objects such as neutron stars as well as cosmological and black hole singularities. Regrettably neutron stars cannot destabilise realistic Planck coupled moduli, which would require objects many orders of magnitude denser. However gravitational collapse, either in matter-dominated universes or in black hole formation, inevitably leads to a destabilisation of the compact volume causing a super-inflationary expansion of the extra dimensions
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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