Gauge field corrections to 11-dimensional supergravity via dimensional reduction

Using the fact that eleven-dimensional supergravity yields type IIA supergravity under dimensional reduction on a circle, we determine higher-derivative terms of 11-dimensional supergravity including the $R^4$, $({\partial {F_4}})^2 R^2$ and $({\partial {F_4}})^4$ terms.Comment: 12 pages, LaTex file, no figure, v2: Published version in EPJ

Two Ramond-Ramond corrections to type II supergravity via field-theory amplitude

Motivated by the standard form of string-theory amplitude, we calculate the field-theory amplitude to complete the higher-derivative terms in type II supergravity theories in their conventional form. We derive explicitly the $O(\alpha'^3)$ interactions for the RR (Ramond-Ramond) fields with graviton, B-field and dilaton in the low-energy effective action of type II superstrings. We check our results by comparison with previous works that have been done by the other methods, and find an exact agreement.Comment: 17 pages, no figure, v2: Published version in EPJ

Pelvic Organ Prolapse-Associated Cystitis

This thesis concerns the construction of 2,3-dihydro-4r7-pyran-4-one and 3(2//)-furanone ring systems by mercury(II)-catalysed reactions, or by more conventional cyclisations, and the potential of such reactions for the synthesis of natural products. Chapter one provides a literature survey of reactions permitting the construction of 2,3-dihydro-4/7-pyran-4-one and 3(2//)-furanone ring systems background literature to relevant natural products is also provided, such as polyether antibiotics, carbohydrates and antitumer agents. Chapter two describes the application of mercury(II)-catalysed cyclisations of dihydroxylated ynones to give 3(2//)-furanones this was achieved by the dihydroxylation of enynones using Sharpless's asymmetric dihydroxylation conditions followed by treatment with a mecury(II) catalyst. The scope and limitations of this method were investigated and shown in several cases to give good yields and high enantiomeric excess. In cases where there was an electron-donating group on the alkyne functionality, such as an ethoxy group, the cyclisation occurred spontaneously during the dihydroxylation step. This methodology was applied for the synthesis of a natural product to confirm the selectivity of the cyclisation step. In chapter three the reactions developed in chapter two formed the basis of a proposed route to the natural product (-)-Pestalotin, a gibberellins synergist. Thus, the Sharpless asymmetric dihydroxylation method was applied to (3,y-unsaturated ketones to give a main intermediate for the synthesis. Chapter four details different approaches to NK10958P, a plant growth regulator. The synthesis of two main fragments was achieved and the coupling of these fragments by syn-selective aldol addition is expected to furnish NK10958 P and its methyl analogue, pironetin, which has been reported to have good cytotoxic and immunosuppressive activity. Full experimental details follow chapter 2-4 and reference sections are provided at the end of each chapter

On Being Religious

The question of religion, in one form or another, has been with us humans for millennia. From primitive tribal ceremonies to highly organized scriptures and theological rule books, up to excruciatingly circumlocutory philosophical treatises, we - Homo sapiens - have attempted to answer the question of religion through ages. Perhaps the most paramount question is whether religion is a real phenomenon that exists outside of us or whether we have invented it. If we have constructed the concept of religion, then our understanding of religion and any action emerging from it would be about us, humans, would it not? If religion is true|something of substance that exists outside and beyond humanity|then we are, as sentient beings with consciousness, mere explorers and we cannot be its inventors, can we? What does this mean? Does this mean there could be no religion without human involvement? Does this mean religion can only manifest itself in a human-centric universe? If so, why is that

Diffusion of Latent Semantic Analysis as a Research Tool: A Social Network Analysis Approach

Latent Semantic Analysis (LSA) is a relatively new research tool with a wide range of applications in different fields ranging from discourse analysis to cognitive science, from information retrieval to machine learning and so on. In this paper, we chart the development and diffusion of LSA as a research tool using Social Network Analysis (SNA) approach that reveals the social structure of a discipline in terms of collaboration among scientists. Using Thomson Reuters’ Web of Science (WoS), we identified 65 papers with “Latent Semantic Analysis” in their titles and 250 papers in their topics (but not in titles) between 1990 and 2008. We then analyzed those papers using bibliometric and SNA techniques such as co-authorship and cluster analysis. It appears that as the emphasis moves from the research tool (LSA) itself to its applications in different fields, citations to papers with LSA in their titles tend to decrease. The productivity of authors fits Lotka’s Law while the network of authors is quite loose. Networks of journals cited in papers with LSA in their titles and topics are well connected

T-duality invariant effective actions at orders α′,α′2 \alpha', \alpha'^2

We use compatibility of the $D$-dimensional effective actions for diagonal metric and for dilaton with the T-duality when theory is compactified on a circle, to find the the $D$-dimensional couplings of curvatures and dilaton as well as the higher derivative corrections to the $(D-1)$-dimensional Buscher rules at orders $\alpha'$ and $\alpha'^2$. We observe that the T-duality constraint on the effective actions fixes the covariant effective actions at each order of $\alpha'$ up to field redefinitions and up to an overall factor. Inspired by these results, we speculate that the $D$-dimensional effective actions at any order of $\alpha'$ must be consistent with the standard Buscher rules provided that one uses covariant field redefinitions in the corresponding reduced $(D-1)$-dimensional effective actions. This constraint may be used to find effective actions at all higher orders of $\alpha'$.Comment: 24 pages, latex file, no figure; v2: major modifications; v3: the version appears in JHE