100 research outputs found
A note on the Hyper--CR equation, and gauged supergravity
We construct a new class of solutions to the dispersionless hyper--CR
equation, and show how any solution to this equation gives rise to a
supersymmetric Einstein--Maxwell cosmological space--time in
--dimensions.Comment: 5 page
Enhanced Euclidean supersymmetry, 11D supergravity and Toda equation
We show how to lift solutions of Euclidean Einstein-Maxwell equations with
non-zero cosmological constant to solutions of eleven-dimensional supergravity
theory with non-zero fluxes. This yields a class of 11D metrics given in terms
of solutions to Toda equation. We give one example of a regular
solution and analyse its supersymmetry.
We also analyse the integrability conditions of the Killing spinor equations
of N=2 minimal gauged supergravity in four Euclidean dimensions. We obtain
necessary conditions for the existence of additional Killing spinors,
corresponding to enhancement of supersymmetry. If the Weyl tensor is
anti-self-dual then the supersymmetric metrics satisfying these conditions are
given by separable solutions to the Toda equation. Otherwise they
are ambi-K\"ahler and are conformally equivalent to K\"ahler metrics of Calabi
type or to product metrics on two Riemann surfaces.Comment: 19 pages. The relationship between our solutions, and those found by
Martelli, Passias and Sparks clarified. A discussion of sufficient conditions
for supersymmetry added. Final version, to appear in JHE
Finding Adiabatically Bound Anions of Guanine through a Combinatorial Computational Approach**
Communication:Remarkable electrophilicity of the oxalic acid monomer: An anion photoelectron spectroscopy and theoretical study
Electrophilicity of Oxalic Acid Monomer Is Enhanced in the Dimer by Intermolecular Proton Transfer
Excess electron induces proton transfer in the dimer of oxalic acid and leads to formation of very stable anions.</p
Combinatorial–computational–chemoinformatics (C3) approach to finding and analyzing low-energy tautomers
Finding the most stable tautomer or a set of low-energy tautomers of molecules is critical in many aspects of molecular modelling or virtual screening experiments. Enumeration of low-energy tautomers of neutral molecules in the gas-phase or typical solvents can be performed by applying available organic chemistry knowledge. This kind of enumeration is implemented in a number of software packages and it is relatively reliable. However, in esoteric cases such as charged molecules in uncommon, non-aqueous solvents there is simply not enough available knowledge to make reliable predictions of low energy tautomers. Over the last few years we have been developing an approach to address the latter problem and we successfully applied it to discover the most stable anionic tautomers of nucleic acid bases that might be involved in the process of DNA damage by low-energy electrons and in charge transfer through DNA. The approach involves three steps: (1) combinatorial generation of a library of tautomers, (2) energy-based screening of the library using electronic structure methods, and (3) analysis of the information generated in step (2). In steps 1–3 we employ combinatorial, computational and chemoinformatics techniques, respectively. Therefore, this hybrid approach is named “Combinatorial*Computational*Chemoinformatics”, or just abbreviated as C3 (or C-cube) approach. This article summarizes our developments and most interesting methodological aspects of the C3 approach. It can serve as an example how to identify the most stable tautomers of molecular systems for which common chemical knowledge had not been sufficient to make definite predictions
The Quest to Quit: an Exploration of the Cessation - Relapse Cycle of Cigarette Smoking
The smoker's perspective is seldom sought in cessation research. Consequently, cessation approaches may be less effective because they are not based on assumptions and interpretations shared by those who smoke. Understanding how chronic relapsing smokers interpret their predicament could enhance cessation approaches,
improving the chances for complete, permanent cessation. To generate such an understanding, five participants were recruited who had attempted to quit smoking several times. Aiming for depth rather than breadth, multiple interviews were conducted with each participant, who also kept an event diary, recording current smoking,
nicotine withdrawal, lapsing and relapsing. Narratology, a biographical method of symbolic interactionism drawing on thematic, structural, and dialogic analysis, was used to elicit the participants' points of view from interview and diary data. The findings show that participants make sense of their chronic relapsing through a master narrative of 'willpower versus weakness'. Meanwhile, the tobacco control domain is largely driven by 'cost', and subsidised treatments are driven by the 'addiction' master narrative. This gap between ways of making sense of smoking and relapse can cause self-stigma, reducing the likelihood that quitting will be attempted and that quit attempts will succeed. Changes are proposed to mitigate the negative effects on self-efficacy
brought about through the present approach to tobacco control. Ways to improve the effectiveness of existing treatments are suggested. Finally, the value of the narrative method is highlighted, with suggestions for its use in research where elucidating the insider
point of view may improve treatment outcomes
Effect of excess electron and one water molecule on relative stability of the canonical and zwitterionic tautomers of glycine
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