The "lessons" of the Australian "heroin shortage"

Heroin use causes considerable harm to individual users including dependence, fatal and nonfatal overdose, mental health problems, and blood borne virus transmission. It also adversely affects the community through drug dealing, property crime and reduced public amenity. During the mid to late 1990s in Australia the prevalence of heroin use increased as reflected in steeply rising overdose deaths. In January 2001, there were reports of an unpredicted and unprecedented reduction in heroin supply with an abrupt onset in all Australian jurisdictions. The shortage was most marked in New South Wales, the State with the largest heroin market, which saw increases in price, dramatic decreases in purity at the street level, and reductions in the ease with which injecting drug users reported being able to obtain the drug. The abrupt onset of the shortage and a subsequent dramatic reduction in overdose deaths prompted national debate about the causes of the shortage and later international debate about the policy significance of what has come to be called the "Australian heroin shortage". In this paper we summarise insights from four years' research into the causes, consequences and policy implications of the "heroin shortage"

Efeito do meio de cultura na calogênese in vitro a partir de folhas de erva-mate.

A organogênese é uma técnica pouco estudada na micropropagação de erva- mate. Este trabalho objetivou avaliar diferentes meios de cultura na calogênese in vitro e organogênese de Ilex paraguariensis St. Hil. Foram coletadas folhas em plantas em casa-de-vegetação. Segmentos foliares foram colocados em meios de cultura 1⁄4 MS, WPM ou JADS, contendo zeatina e 2,4-D. O meio MS foi mais eficiente na indução de calos. No meio WPM foi observada rizogênese. Nos meios testados não houve formação de brotações adventícias.Nota Científica

Properties of simulated sunspot umbral dots

Realistic 3D radiative MHD simulations reveal the magneto-convective processes underlying the formation of the photospheric fine structure of sunspots, including penumbral filaments and umbral dots. Here we provide results from a statistical analysis of simulated umbral dots and compare them with reports from high-resolution observations. A multi-level segmentation and tracking algorithm has been used to isolate the bright structures in synthetic bolometric and continuum brightness images. Areas, brightness, and lifetimes of the resulting set of umbral dots are found to be correlated: larger umbral dots tend to be brighter and live longer. The magnetic field strength and velocity structure of umbral dots on surfaces of constant optical depth in the continuum at 630 nm indicate that the strong field reduction and high velocities in the upper parts of the upflow plumes underlying umbral dots are largely hidden from spectro-polarimetric observations. The properties of the simulated umbral dots are generally consistent with the results of recent high-resolution observations. However, the observed population of small, short-lived umbral dots is not reproduced by the simulations, possibly owing to insufficient spatial resolution.Comment: Accepted for publication in A&

Searching for overturning convection in penumbral filaments: slit spectroscopy at 0.2 arcsec resolution

Recent numerical simulations of sunspots suggest that overturning convection is responsible for the existence of penumbral filaments and the Evershed flow, but there is little observational evidence of this process. Here we carry out a spectroscopic search for small-scale convective motions in the penumbra of a sunspot located 5 deg away from the disk center. The position of the spot is very favorable for the detection of overturning downflows at the edges of penumbral filaments. Our analysis is based on measurements of the Fe I 709.0 nm line taken with the Littrow spectrograph of the Swedish 1 m Solar Telescope under excellent seeing conditions. We compute line bisectors at different intensity levels and derive Doppler velocities from them. The velocities are calibrated using a nearby telluric line, with systematic errors smaller than 150 m/s. Deep in the photosphere, as sampled by the bisectors at the 80%-88% intensity levels, we always observe blueshifts or zero velocities. The maximum blueshifts reach 1.2 km/s and tend to be cospatial with bright penumbral filaments. In the line core we detect blueshifts for the most part, with small velocities not exceeding 300 m/s. Redshifts also occur, but at the level of 100-150 m/s, and only occasionally. The fact that they are visible in high layers casts doubts on their convective origin. Overall, we do not find indications of downflows that could be associated with overturning convection at our detection limit of 150 m/s. Either no downflows exist, or we have been unable to observe them because they occur beneath tau=1 or the spatial resolution/height resolution of the measurements is still insufficient.Comment: Accepted for publication in Ap