Aspects of brane-antibrane inflation

I describe a dynamical mechanism for solving the fine-tuning problem of brane-antibrane inflation. By inflating with stacks of branes and antibranes, the branes can naturally be trapped at a metastable minimum of the potential. As branes tunnel out of this minimum, the shape of the potential changes to make the minimum shallower. Eventually the minimum disappears and the remaining branes roll slowly because the potential is nearly flat. I show that even with a small number of branes, there is a good chance of getting enough inflation. Running of the spectral index is correlated with the tilt in such a way as to provide a test of the model by future CMB experiments.Comment: 6 pages, 5 figures; proceedings of Theory Canada 1 conference, 2-5 June 2005, UBC, Vancouve

Consolidation of complex events via reinstatement in posterior cingulate cortex

It is well-established that active rehearsal increases the efficacy of memory consolidation. It is also known that complex events are interpreted with reference to prior knowledge. However, comparatively little attention has been given to the neural underpinnings of these effects. In healthy adult humans, we investigated the impact of effortful, active rehearsal on memory for events by showing people several short video clips and then asking them to recall these clips, either aloud (Experiment 1) or silently while in an MRI scanner (Experiment 2). In both experiments, actively rehearsed clips were remembered in far greater detail than unrehearsed clips when tested a week later. In Experiment 1, highly similar descriptions of events were produced across retrieval trials, suggesting a degree of semanticization of the memories had taken place. In Experiment 2, spatial patterns of BOLD signal in medial temporal and posterior midline regions were correlated when encoding and rehearsing the same video. Moreover, the strength of this correlation in the posterior cingulate predicted the amount of information subsequently recalled. This is likely to reflect a strengthening of the representation of the video's content. We argue that these representations combine both new episodic information and stored semantic knowledge (or "schemas"). We therefore suggest that posterior midline structures aid consolidation by reinstating and strengthening the associations between episodic details and more generic schematic information. This leads to the creation of coherent memory representations of lifelike, complex events that are resistant to forgetting, but somewhat inflexible and semantic-like in nature

Atom chips on direct bonded copper substrates

We present the use of direct bonded copper (DBC) for the straightforward fabrication of high power atom chips. Atom chips using DBC have several benefits: excellent copper/substrate adhesion, high purity, thick (> 100 microns) copper layers, high substrate thermal conductivity, high aspect ratio wires, the potential for rapid (< 8 hr) fabrication, and three dimensional atom chip structures. Two mask options for DBC atom chip fabrication are presented, as well as two methods for etching wire patterns into the copper layer. The wire aspect ratio that optimizes the magnetic field gradient as a function of power dissipation is determined to be 0.84:1 (height:width). The optimal wire thickness as a function of magnetic trapping height is also determined. A test chip, able to support 100 A of current for 2 s without failing, is used to determine the thermal impedance of the DBC. An assembly using two DBC atom chips to provide magnetic confinement is also shown.Comment: 8 pages, 5 figure

The development of marine biotechnology in Oman: Potential for capacity building through open innovation

This study examines the current state of the art in the emerging and strategically important marine biotechnology sector in Oman, which has a long coastline, rich marine heritage and strong fishing industry. In a knowledge-based economy, the ability to innovate is a key factor for increasing organisational competitiveness and this may be achieved using open innovation. This is the use by firms of external knowledge, ideas and technology to innovate. In this study, the extent of open innovation in Omani marine bioindustry companies has been studied by examining data from the top sixteen companies ranked by number of employees. The results indicate that the extent of openness in these companies is higher towards market side activities. In addition, the use of open innovation to increase collaboration between companies, Universities and government research institutes needs to be significantly strengthened

Stability of Neutrinos in the Singlet Majoron Model

We show that there is no one-loop enhancement of the rate for a light neutrino to decay into a lighter neutrino plus a majoron, contrary to a recent claim. Thus the light neutrinos must satisfy the cosmological bound of having masses less than 35 eV in the singlet majoron model, or else violate the constraint imposed by galaxy formation. In the latter case, $\nu_\tau$ could have a mass between 40 and 500 keV, while satisfying all other cosmological constraints.Comment: 11 pp., latex, UMN-TH-1218-93. Correct nucleosynthesis bound of 500 keV on nu_tau mass is incorporated; one-loop electroweak contribution to neutrino mass is correcte

Measurement of open innovation in the marine biotechnology sector in Oman

National economies are often strengthened by diversification, which is built in turn on a healthy and productive culture of national innovation. Innovation is a complex process, which is difficult to measure in an objective manner. In this work and for the first time, a quantitative measure for open innovation has been developed and validated to determine the performance of a firm within the marine biotechnology sector in Oman. This breakthrough was achieved in four steps. First, the characteristics of the two dimensions of open innovation ('breadth' and 'depth') were identified using a critical review of the literature and a series of pre-tests of a survey design with industrial experts. Second, a quantitative index for open innovation by measuring these two dimensions at firm level was developed. Third, validation of this five-item scale was conducted using the UK Community Innovation Survey (CIS) data set. Fourth, the five-item scale was applied to 22 firms in the marine bio-industry sector in Oman using a case study approach, and was used to rank the firms according to their open innovation index. This analysis shows how Omani marine bio-industry firms could strengthen their open innovation efforts, for example by collaborating more effectively with government organizations and research institutes to thereby boost the quality of their open innovation activities in a measurable way

Real-time D-brane condensation

Unstable D-branes or brane-antibrane systems can decay to lower-dimensional branes. In the effective field theory description, the final state branes are defects in the tachyon field which describes the initial instability. We study the dynamical formation of codimension one defects (kinks) using Sen's ansatz for the tachyon Lagrangian. It is shown that the slope of the kink diverges within a finite amount of time after the tachyon starts to roll. We discuss the relevance for reheating after brane-antibrane inflation.Comment: 10 pages, 5 figures; added reference to hep-th/020710