\u3cem\u3eDe Novo\u3c/em\u3e [PSI\u3csup\u3e+\u3c/sup\u3e] Prion Formation Involves Multiple Pathways to Form Infectious Oligomers

Prion and other neurodegenerative diseases are associated with misfolded protein assemblies called amyloid. Research has begun to uncover common mechanisms underlying transmission of amyloids, yet how amyloids form in vivo is still unclear. Here, we take advantage of the yeast prion, [PSI +], to uncover the early steps of amyloid formation in vivo. [PSI +] is the prion form of the Sup35 protein. While [PSI +] formation is quite rare, the prion can be greatly induced by overexpression of the prion domain of the Sup35 protein. This de novo induction of [PSI +] shows the appearance of fluorescent cytoplasmic rings when the prion domain is fused with GFP. Our current work shows that de novoinduction is more complex than previously thought. Using 4D live cell imaging, we observed that fluorescent structures are formed by four different pathways to yield [PSI +] cells. Biochemical analysis of de novo induced cultures indicates that newly formed SDS resistant oligomers change in size over time and lysates made from de novo induced cultures are able to convert [psi −] cells to [PSI +] cells. Taken together, our findings suggest that newly formed prion oligomers are infectious

Insiders and the law: the impact of Regulatory Change on Insider Trading

The impact of regulations in minimizing the detrimental effects of insider trading is unsettled. In this paper, we investigate the impact of the introduction of the Securities Market Amendment Act 2002 in New Zealand on several aspects of the market. After examining a sample of companies listed before and after the new laws introduction, we find strong evidence of a reduction in the cost of capital, bid-ask spreads and volatility accompanied by increases in liquidity, all as predicted. We conclude that the change in regulations has had a positive impact on the market

Do insiders crowd out analysts?

Both insiders and analysts are involved in the collection and dissemination of information to the market, roles which impact heavily on price efficiency and resource allocation. The differences between the two groups, however, result in a competitive relationship with analysts at a disadvantage as they face greater costs associated with information gathering. As a result they may choose not to participate in a onesided competition. We employ transaction data to examine the impact of firm-year aggregate insider trading intensity on the level of analyst following. We find a negative relationship between insider trading intensity and analyst coverage. This result was driven by large blockholders suggesting that analysts are attracted to higher levels of information asymmetry from which they profit

Degenerate Sectors of the Ashtekar Gravity

This work completes the task of solving locally the Einstein-Ashtekar equations for degenerate data. The two remaining degenerate sectors of the classical 3+1 dimensional theory are considered. First, with all densitized triad vectors linearly dependent and second, with only two independent ones. It is shown how to solve the Einstein-Ashtekar equations completely by suitable gauge fixing and choice of coordinates. Remarkably, the Hamiltonian weakly Poisson commutes with the conditions defining the sectors. The summary of degenerate solutions is given in the Appendix.Comment: 19 pages, late

Lateral grating DFB AlGaInN laser diodes for optical communications and atomic clocks

AlGaInN laser diode technology is of considerable interest for telecom applications and next generation atomic optical clocks based on Sr (by using 422nm & 461nm) and Rb at 420.2nm.Very narrow linewidths (<1MHz) are required for such applications. We report lateral gratings on AlGaInN ridge waveguide laser diodes to achieve a single wavelength device with a good side mode suppression ratio (SMSR) that is suitable for atomic clock and telecom applications