Geometrical interpretation of extended supergravity

SO₂ extended supergravity is shown to be a geometrical theory, whose underlying gauge group is OSp(4, 2). The couplings which gauge the SO₂ symmetry as well as the accompanying cosmological and masslike terms are directly obtained, and the usual SO₂ model is obtained after a Wigner-Inönü group contraction.     

What is Conservation Science?

‘Conservation science’ or ‘cultural heritage research’ is defined through a discussion of research needs, training and employment patterns world-wide, and trends in published work. Parallels with mainstream polymer science are drawn throughout. Some aspects are discussed in more detail: traditional paint composites; studies in modern, synthetic, paint composites; the relevance of accelerated ageing to a range of polymer types.     

Gamma-ray,X-ray and ultraviolet light induced low temperature thermoluminescencez of KN3 and NaN3

Abstract

On évalue, pour une chaine atomique linéaire, la variation du coefficient de dilatation thermique Δ α lorsque la chaine est sous contrainte. On en déduit la variation du module de Young avec la température. L'accord raisonnable, sur ce second point, avec les résultats expérimentaux montre que le sens de variation trouvé pour Δ α demeure, au moins qualitativement, pour un cristal à 3 dimensions.

On montre alors que, pour un cristal irradié sous contrainte par des particules de grande énergie, cette variation Δ α peut entrainer une contribution négative au fluage.

THERMAL EXPANSION OF A LINEAR CHAIN UNDER STRESS APPLICATION TO CREEP UNDER IRRADIATION

Variations of thermal expansion coefficient Δ α of a linear atomic row under stress, are evaluated. Variations of Young's modulus with temperature are deduced. A reasonable agreement, on this point, with experimental measurements indicates that at least the sign obtained for Δ α subsists qualitatively for a 3-dimensional crystal.

It is then shown that, for a crystal irradiated under stress with high energy particles, this variation Δ α may lead to a negative contribution to creep.     

Supertwistors and massive particles

In the (super)twistor formulation of massless (super)particle mechanics, the mass-shell constraint is replaced by a “spin-shell” constraint from which the spin content can be read off. We extend this formalism to massive (super)particles (with N$N$-extended space–time supersymmetry) in three and four space–time dimensions, explaining how the spin-shell constraints are related to spin, and we use it to prove equivalence of the massive N=1$N=1$ and BPS-saturated N=2$N=2$ superparticle actions. We also find the supertwistor form of the action for “spinning particles” with N$N$-extended worldline supersymmetry, massless in four dimensions and massive in three dimensions, and we show how this simplifies special features of the N=2$N=2$ case.     

Following the excited state relaxation dynamics of indole and 5-hydroxyindole using time-resolved photoelectron spectroscopy

Time-resolved photoelectron spectroscopy was used to obtain new information about the dynamics of electronic relaxation in gas-phase indole and 5-hydroxyindole following UV excitation with femtosecond laser pulses centred at 249 nm and 273 nm. Our analysis of the data was supported by ab initio calculations at the coupled cluster and complete-active-space self-consistent-field levels. The optically bright (1)L(a) and (1)L(b) electronic states of (1)ππ? character and spectroscopically dark and dissociative (1)πσ? states were all found to play a role in the overall relaxation process. In both molecules we conclude that the initially excited (1)L(a) state decays non-adiabatically on a sub 100 fs timescale via two competing pathways, populating either the subsequently long-lived (1)L(b) state or the (1)πσ? state localised along the N-H coordinate, which exhibits a lifetime on the order of 1 ps. In the case of 5-hydroxyindole, we conclude that the (1)πσ? state localised along the O-H coordinate plays little or no role in the relaxation dynamics at the two excitation wavelengths studied.     

Preparation of Benz[b]Indeno[1,2-e]Pyran-11(6H)-Ones and Benz[b]Indeno[1,2-e]Thiopyran-11(6H)-One from Dilithiated 2-Indanone and Lithiated Methyl Salicylates or Lithiated Methyl Thiosalicylate

Dilithiated 2-indanone was prepared with excess lithium diisopropylamide, and the resulting intermediate was condensed with several lithiated methyl salicylates or lithiated methyl thiosalicylate, which was followed by acid cyclization to benz[b]indeno[1,2-e]pyran-11(6H)-ones 3--9 or benz[b]indeno[1,2-e]thiopyran-11(6H)-one 10, which are rare fused-ring indeno-chromones and a new indeno-thiochromone, respectively.     

Invariance of actions,rheonomy, and the new minimal N = 1 supergravity in the group manifold approach

A new definition of rheonomy is proposed based on Bianchi identities instead of field equation. For theories with auxiliary fields, the transformation rules are obtained in a completely geometrical way and invariance of the action is equivalent to d$\text{P}$ = 0, which means surface-independence of the action integral. For theories without auxiliary fields, the transformation rules are found by requiring that the action be invariant, just as in the component approach. Previous methods of obtaining the transformation rules which start from rheonomy of field equations and use certain recipes to find the off-shell extensions of the rules are abandoned. New minimal supergravity is worked out in detail; it is the gauge theory based on a free differential algebra which includes the auxiliary fields.