Precession during merger 1: Strong polarization changes are observationally accessible features of strong-field gravity during binary black hole merger

The short gravitational wave signal from the merger of compact binaries encodes a surprising amount of information about the strong-field dynamics of merger into frequencies accessible to ground-based interferometers. In this paper we describe a previously-unknown "precession" of the peak emission direction with time, both before and after the merger, about the total angular momentum direction. We demonstrate the gravitational wave polarization encodes the orientation of this direction to the line of sight. We argue the effects of polarization can be estimated nonparametrically, directly from the gravitational wave signal as seen along one line of sight, as a slowly-varying feature on top of a rapidly-varying carrier. After merger, our results can be interpreted as a coherent excitation of quasinormal modes of different angular orders, a superposition which naturally "precesses" and modulates the line-of-sight amplitude. Recent analytic calculations have arrived at a similar geometric interpretation. We suspect the line-of-sight polarization content will be a convenient observable with which to define new high-precision tests of general relativity using gravitational waves. Additionally, as the nonlinear merger process seeds the initial coherent perturbation, we speculate the amplitude of this effect provides a new probe of the strong-field dynamics during merger. To demonstrate the ubiquity of the effects we describe, we summarize the post-merger evolution of 104 generic precessing binary mergers. Finally, we provide estimates for the detectable impacts of precession on the waveforms from high-mass sources. These expressions may identify new precessing binary parameters whose waveforms are dissimilar from the existing sample.Comment: 11 figures; v2 includes response to referee suggestion

Measuring Strong and Weak Phases in Time-Independent B Decays

Flavor SU(3) symmetry implies certain relations among $B$-decay amplitudes to $\pi\pi$, $\pi K$ and $K {\bar K}$ final states, when annihilation-like diagrams are neglected. Using three triangle relations, we show how to measure the weak CKM phases $\alpha$ and $\gamma$ using time-independent rate measurements only. In addition, one obtains all the strong final-state phases and the magnitudes of individual terms describing tree (spectator), color-suppressed and penguin diagrams. Many independent measurements of these quantities can be made with this method, which helps to eliminate possible discrete ambiguities and to estimate the size of SU(3)-breaking effects.Comment: 2 figures available from the authors upon request, 12 pages,UdeM-LPN-TH-94-19

Effects of disorder on the vortex charge

We study the influence of disorder on the vortex charge, both due to random pinning of the vortices and due to scattering off non-magnetic impurities. In the case when there are no impurities present, but the vortices are randomly distributed, the effect is very small, except when two or more vortices are close by. When impurities are present, they have a noticeable effect on the vortex charge. This, together with the effect of temperature, changes appreciably the vortex charge. In the case of an attractive impurity potential the sign of the charge naturally changes.Comment: 10 pages, 16 figures. Accepted in Phys. Rev.

Confinement in the management of drug-resistant TB: The unsavoury prospect of balancing individual human rights and the public good

In the context of expanding TB and HIV epidemics in South Africa, the decision to enforce non-voluntary admission for XDR TB raises many ethical and human rights dilemmas, principally because it trades off the human rights of individuals against the public good. However, the dichotomy may also involve competing rights claims and rights obligations of the state to control infectious diseases. A more careful rights analysis is provided, using established analytical frameworks, to elicit the possible criteria that could justify limitation of individual rights. Generally, only in very restricted situations where there is a clearly defined risk to one or more third parties, based on evidence, and conditional on thorough consideration of available alternatives, could non-voluntary admission be considered. Community-based strategies will need to be developed to cope with infection control without forced admission for most cases. Even when compulsory admission is needed, strict adherence to administrative justice procedures would be required. Confinement has no place as a strategy for the broader control of an epidemic which should be contingent on improved health system functioning and addressing the abysmal investment in research and development for drugs for neglected diseases worldwide.South African Journal of Bioethics and Law Vol. 1 (1) 2008: pp. 11-1

Agrichemical safety practices on farms in the western Cape

In order to study agrichemical safety practices in a rural farming area in the western Cape, an audit of 45 randomly sampled farms was performed over 3 months in 1992. A response rate of 87% was achieved, and the survey results suggest that approximately 9% of permanent and 14% of seasonal farm workers are employed in jobs with potential exposure to agrichemicals. While protective equipment was widely available, gloves and masks were seldom used, with little enforcement or commercial support from the suppliers of the equipment. Farm workers receive little training on pesticide safety, but interest in the possibility of further training for workers was high. In the absence of a system of pesticide disposal, the presence of residual, unwanted and outdated stocks of pesticides in farmers' stores, and to a lesser extent the presence of empty containers, are identified as important problems. Current pesticide storage practices require improvement by simple industrial hygiene measures. Health facilities available to workers on most farms are extremely limited, particularly in the light of statutory requirements for occupational safety and health under the Machinery and Occupational Safety Act. It is argued that collective solutions to problems of pesticide safety are possible within the ambit of a public health response, particularly given the willingness of the farming community to identify and address potential health problems. As a result, initiatives to meet these needs are currently under way in the region.