'Face Up to the Truth': Helping Gay Men in Vietnam Protect Themselves from AIDS.

Appropriate AIDS prevention information is not available in Vietnam for men who have sex with men. Current AIDS prevention messages can be misunderstood with potentially dangerous results. We outline some features of gay culture in a provincial city in Vietnam. We describe the activities of a peer educator who made contact with a small group of young gay men during 1996 and 1997. All the young men were ill-informed about AIDS. Their attitudes and sexual practices made them vulnerable to AIDS. The peer educator provided clear information and emotional support. The peer education was done without government endorsement and on a very low budget

Impact of the Delta (1232) resonance on neutral pion photoproduction in chiral perturbation theory

We present an ongoing project to assess the importance of D-waves and the $\Delta (1232)$ resonance for descriptions of neutral pion photoproduction in Heavy Baryon Chiral Perturbation Theory. This research has been motivated by data published by the A2 and CB-TAPS collaborations at MAMI [1]. This data has reached unprecedented levels of accuracy from threshold through to the $\Delta$ resonance. Accompanying the experimental work, there has also been a series of publications studying the theory that show that, to go beyond an energy of $E_\gamma=170$ MeV, it is necessary to include other aspects, in particular the $\Delta (1232)$ as a degree of freedom [2] and possibly higher partial waves [3].Comment: Proceedings to the 8th International Workshop on Chiral Dynamics 201

Magnetic field structure of the extended 3C 380 jet

An earlier study of the complex jet of 3C 380 by Papageorgiou et al. revealed total intensity and polarization structure associated with a bright knot K1 about 0.7 arcsec from the core that was reminiscent of that expected for a conical shock wave. In this new study, 1.42, 1.66 and 4.99 GHz total intensity, polarization and Faraday rotation images are presented and analysed. These images were derived from observations with the Very Long Baseline Array plus one antenna of the Very Large Array, obtained in 2006 March. These new images confirm the overall magnetic field structure of the knot K1 indicated in the earlier observations. In addition, a clear Faraday rotation gradient has been detected across the jet, extending roughly from 10 to 30 mas (70–200 pc) along the jet from the core (a radial distance of approximately two beamwidths). The gradient spans roughly 3.5 beamwidths in the transverse direction, and the difference in the rotation measures on either side of the jet is 4–5σ, demonstrating that the detection of the gradient is firm. We interpret this transverse Faraday rotation gradient as reflecting systematic variation of the line-of-sight component of a helical or toroidal magnetic field (B) associated with the jet of 3C 380. These results provide evidence that the helical field arising due to the joint action of the rotation of the central black hole and its accretion disc and the jet outflow can survive to distances of hundreds of parsecs from the central engine

Radiative transfer of synchrotron radiation through a compressed random magnetic field

The generally low polarization levels present in extragalactic radio sources suggest magnetic fields that are largely turbulent, presumably maintained by turbulence motion of the underlying plasma. The polarization of radio emission is often generated as the plasma is compressed by shock waves, and this type of configuration has been widely applied, from the cores of AGN to the lobes of classical double radio sources. Here we note that, in the absence of Faraday rotation, the synchrotron radiative transfer equations for such a configuration, separate, leading to relatively simple solutions for opaque or partially opaque sources. Expressions for the emission and absorption coefficients are derived, and, although in general, these must be evaluated numerically, the process is much simpler than a full numerical solution of the transfer equations

86 GHz Very Long Baseline Polarimetry of 3C273 and 3C279 with the Coordinated Millimeter VLBI Array

86 GHz Very Long Baseline Polarimetry probes magnetic field structures within the cores of Active Galactic Nuclei at higher angular resolutions and a spectral octave higher than previously achievable. Observations of 3C273 and 3C279 taken in April 2000 with the Coordinated Millimeter VLBI Array have resulted in the first total intensity (Stokes I) and linear polarization VLBI images reported of any source at 86 GHz. These results reveal the 86 GHz electric vector position angles within the jets of 3C273 and 3C279 to be orthogonal to each other, and the core of 3C273 to be unpolarized. If this lack of polarization is due to Faraday depolarization alone, the dispersion in rotation measure is >=90000 rad/m^2 for the core of 3C273.Comment: AASTeX v5.02; 10 pages; 4 figures; accepted for publication in the Astrophysical Journal Letter

Gleaning Secrets from the Transverse Profiles of AGN jets

Both the emission properties and evolution of Active Galactic Nuclei (AGN) radio jets are dependent on the magnetic fields that thread them. A better understanding of these magnetic fields is therefore important in helping our understanding of jets in AGN. Several observations of jets have suggested that, on parsec scales, the jet magnetic field may have a significant helical component. Using a model first proposed by Laing and developed by Papageorgiou and Cawthorne, all of the above observations can be reproduced by varying only the helical pitch angle of the magnetic field and the line of sight angle. In order to reduce the total polarization to agree with observed values, a tangled magnetic field component is also introduced to the model, via another parameter, the degree of entanglement. We are in the process of comparing data from observations of several AGN with this model, making it possible to derive estimates of the helical pitch angle, the viewing angle and the degree of entanglement for these jets in the framework of this model. The observed profiles are compared with a set of theoretical profiles. This proves to be an objective approach to profile fitting that should enable analysis of a large number of AGN jets, making it possible to look for trends. Results for Mrk501 are presented

Specialist tissue viability services: a priority or a luxury?

During the 1980s, the number of tissue viability nurses (TVNs) rose steadily in the UK, in response to mismanagement of patients with wounds (Fletcher, 1995). Since this time, and in response to the quality agenda, the necessity of promoting a tissue viability service (TVS) that is able to meet the needs of a changing population, while being cost effective and offering interventions based on research and evidence, has grown. The drive to reduce avoidable harm in healthcare and to make efficiency savings is continuing, with TVS being one of the key areas to deliver these targets. However, across the UK we have a wide range of role descriptions and job titles, yet little clarification as to the qualifications and skills required to deliver a successful TVS. Infection control specialist nurses have a clear identity with concise role descriptions representing a range of pay bands. Arguably, this is because they are aligned with a medical specialty, whereas TV is not. The introduction of ‘Any Qualified Provider’ (Department of Health, 2011) has witnessed some services, including management of leg ulceration, being delivered by non-NHS providers at a reduced cost. So is TVS in danger of becoming more of a ‘nice thing’ rather than a priority

Rights under International Humanitarian Law

The idea of ‘rights’ under the law of war historically referred to state or belligerent rights – that is, rights to engage in actions not permitted under the law of peace. The different sense of rights of individuals was absent from those traditional accounts of the law, and whether individuals are granted rights (for example, of prisoners of war to be humanely treated, of civilians not to be targeted) under contemporary international humanitarian law (IHL) remains contested. This article explores how this debate has developed in recent history. It argues that clear support for the notion of individual rights during the drafting of the 1907 Hague Convention IV and subsequent treaties seemed to be overtaken by state practice in the area of war reparations, only to re-emerge in more recent practice that, in part, is shown to be a result of a more legalized approach to the invocation of responsibility for IHL violations. This growing support for the individual rights perspective of IHL is then juxtaposed with the re-emergence of state rights. The article concludes that these two different notions of ‘rights’ under IHL present two fundamentally opposing visions for the law’s role in regulating armed conflict

Variability of the Centimeter-Submillimeter Spectrum and Polarization of 3C 273 during Outburst

Original article can be found at: http://www.journals.uchicago.edu/ApJ/--Copyright University of Chicago Press/ AASCentimeter to submillimeter total flux and polarization monitoring data are used to investigate the nature of a prominent flare in the quasar 3C 273 during 1995/6. After removal of the quiescent level, the resulting “flare spectra" are well fitted by a simple homogeneous synchrotron source model, which in turn allows the movement of the self-absorption turnover to be tracked during the flare. Both the flare amplitude/time delay relationship and the overall spectral evolution are qualitatively consistent with existing models. The early evolution of the spectrum is best determined and is shown to be in excellent agreement with the Compton stage of the Marscher & Gear shock model. However, the polarization behavior during the flare is different at millimeter and centimeter wavelengths and the observations are difficult to reconcile with a simple transverse shock. They are, however, consistent with a conical shock for which the observed polarization properties vary with distance along the jet. Such variations may be caused, for example, by a change in cone angle owing to disruption caused by the growing component of the magnetic field parallel to the jet axis or by a moderate change in viewing angle.Peer reviewe

Polarization of synchrotron emission from relativistic reconfinement shocks

We study the polarization properties of relativistic reconfinement shocks with chaotic magnetic fields. Using our hydrodynamical model of their structure, we calculate synthetic polarization maps, longitudinal polarization profiles and discuss the spatially averaged polarization degree as a function of jet half-opening angle Theta_j, jet Lorentz factor Gamma_j and observer inclination angle to the jet axis theta_{obs}. We find, that for theta_{obs} <= Theta_j the wave electric vectors are parallel in the vicinity of the structure ends and perpendicular in between, while for theta_{obs} > Theta_j the polarization can only be perpendicular. The spatially averaged polarization degree does not exceed 30%. Parallel average polarization, with polarization degrees lower than 10%, have been found for theta_{obs} < Theta_j under the condition Gamma_j * Theta_j > 1. As earlier works predicted the parallel polarization from relativistic conical shocks, we explain our results by discussing conical shocks with divergent upstream flow.Comment: 8 pages, 10 figures, accepted for publication in MNRA