Semi-local Cosmic Strings and the Cosmological Constant Problem

We study the cosmological constant problem in a three-dimensional N=2 supergravity theory with gauge group SU[2]_{global}xU[1]_{local}. The model we consider is known to admit string-like configurations, the so-called semi-local cosmic strings. We show that the stability of these solutions is provided by supersymmetry through the existence of a lower bound for the energy, even though the manifold of the Higgs vacuum does not contain non-contractible loops. Charged Killing spinors do exist over configurations that saturate the Bogomolnyi bound, as a consequence of an Aharonov-Bohm-like effect. Nevertheless, there are no physical fermionic zero modes on these backgrounds. The exact vanishing of the cosmological constant does not imply, then, Bose-Fermi degeneracy. This provides a non-trivial example of the recent claim made by Witten on the vanishing of the cosmological constant in three dimensions without unphysical degeneracies.Comment: 12 pages, LaTeX. To appear in Physics Letters

The Function of Self-Consciousness in John Barth\u27s Chimera

Much recent American fiction has become increasingly self-conscious, displaying an awareness of itself as fiction, as artifice that diminishes the role of a central human consciousness or self in the fiction. The fictional process is in the foreground of much contemporary fiction where the narrative human presence once was. Yet, both fictional process and human presence serve similar structural functions within the text, which suggests that the creation of a fiction resembles the creation of a human self, real or imaginary. The provisional reality of self-conscious fiction is like the provisional reality of the post-modern self, prone to self-questioning, constituted by process rather than substance, multiple, changeable, perhaps even illusory. John Barth\u27s novel Chimera is a supremely self-conscious fiction. Barth\u27s use of the three central narrators in the three sections of the novel— the Dunyazadiad , the Perseid , and the Bellerophoniad — foregrounds the relationship between diffusion of identity and artistic self-consciousness within the novel. Although an individual, by definition, should not be susceptible to division or separation into parts without losing its identity, the narrators in Chimera, like the novel\u27s sections, are all divisible, incomplete, or inter-changeable. Definitions of identity often include elements such as continuity, functional unity, consciousness, récognitive memory, personality, or awareness. Yet, there is still a question about the relation of a self so constituted to se//-conscious fiction

Pumped two-phase heat transfer loop

A pumped loop two-phase heat transfer system, operating at a nearly constant temperature throughout, includes a plurality of independently operating grooved capillary heat exchanger plates supplied with working fluid through independent flow modulation valves connected to a liquid supply line, a vapor line for collecting vapor from the heat exchangers, a condenser between the vapor and the liquid lines, and a fluid circulating pump between the condenser and the heat exchangers

Singularity Resolution in Gauged Supergravity and Conifold Unification

We obtain a unified picture for the conifold singularity resolution. We propose that gauged supergravity, through a novel prescription for the twisting, provides an appropriate framework to smooth out singularities in the context of gravity duals of supersymmetric gauge theories.Comment: 13 pages, harvmac, one figure; v2: reference adde

The role of platelet microvesicles in intercellular communication.

In recent years, there has been exponential growth in the interest in microvesicles, which is reflected by the number of publications. Initially referred to as platelet dust by Peter Wolf in 1967, platelet microvesicles (PMV) are now recognized as important mediators of intercellular communication. There are examples of PMV exerting physiological effects on almost all hematological and vascular cell types, including monocytes, macrophages, neutrophils, T-cells, endothelium cells, and smooth muscle cells (SMCs). PMV can exert these effects by multiple methods: extracellular signaling through receptors, transfer of surface molecules, and delivery of intracellular contents including miRNA. Recent work suggests a complex environment in which cellular contents are being shared multi-directionally between multiple cell types. This review will focus on the communicative properties of PMV

BPS Solitons and Killing Spinors in Three Dimensional N=2 Supergravity

In the framework of three dimensional extended supergravity theories, we demonstrate that there exist non-trivial Killing spinors over BPS soliton configurations, even when the space-time is asymptotically conical. We also show that there are no physical fermionic zero modes on these backgrounds. We further generalize these results to the case of semilocal systems.Comment: 7 pages, LaTeX. Short Talk given at the Meeting ``Trends in Theoretical Physics'', April 28th-May 6th, 1997, La Plata, Argentin

A study of the opportunities for gross muscular activity outside of nursery school of two different groups of four-year-old children in relation to their behavior in nursery school in terms of "tension outbursts".

Thesis (Ed.M.)--Boston Universit

Strong coupling expansion and Seiberg-Witten-Whitham equations

We study the Seiberg-Witten-Whitham equations in the strong coupling regime of the N=2 super Yang-Mills theory in the vicinity of the maximal singularities. In the case of SU(2) the Seiberg-Witten-Whitham equations fix completely the strong coupling expansion. For higher rank SU(N) they provide a set of non-trivial constraints on the form of this expansion. As an example, we study the off-diagonal couplings at the maximal point for which we propose an ansatz that fulfills all the equations.Comment: 10 pages, LaTeX, no figures; v2: The expression for the off-diagonal couplings has been corrected and numerical checks have been extended. One reference adde