Cosmological Moduli Dynamics

Low energy effective actions arising from string theory typically contain many scalar fields, some with a very complicated potential and others with no potential at all. The evolution of these scalars is of great interest. Their late time values have a direct impact on low energy observables, while their early universe dynamics can potentially source inflation or adversely affect big bang nucleosynthesis. Recently, classical and quantum methods for fixing the values of these scalars have been introduced. The purpose of this work is to explore moduli dynamics in light of these stabilization mechanisms. In particular, we explore a truncated low energy effective action that models the neighborhood of special points (or more generally loci) in moduli space, such as conifold points, where extra massless degrees of freedom arise. We find that the dynamics has a surprisingly rich structure - including the appearance of chaos - and we find a viable mechanism for trapping some of the moduli.Comment: 35 pages, 14 figures, references adde

Role of bevacizumab therapy in the management of glioblastoma

Glioblastoma is one of the most common primary brain tumors and one of the most difficult to treat. In population-based studies only 30% of patients will survive 1 year and in the most efficacious surgery, irradiation, and chemotherapy clinical trials approximately 20% will live 2 years. Bevacizumab is a recombinant, antivascular epidermal growth factor receptor (VEGF) monoclonal antibody with 6 VEGF-binding residues that binds to VEGF, preventing VEGF from binding to its target, VEGFR-1 and VEGFR-2, on endothelial cells. Through its binding to VEGF ligands bevacizumab reduces tumor angiogenesis and vasogenic brain edema; the consequences are that bevacizumab reduces the rate of glioblastoma tumor growth and its associated tumoral edema, thereby improving quality of life and survival for patients suffering from cerebral glioblastoma. In this review, we will summarize the studies that led to the use of bevacizumab in glioblastoma and the potential side-effects and complications that can be associated with its use and, finally, new opportunities for drug combinations with bevacizumab

Quantum walk-based search and centrality

We study the discrete-time quantum walk-based search for a marked vertex on a graph. By considering various structures in which not all vertices are equivalent, we investigate the relationship between the successful search probability and the position of the marked vertex, in particular its centrality. We find that the maximum value of the search probability does not necessarily increase as the marked vertex becomes more central and we investigate an interesting relationship between the frequency of the successful search probability and the centrality of the marked vertex.Comment: 29 pages, 17 figure