Complex structure within Saturn’s infrared aurora

The majority of planetary aurorae are produced by electrical currents flowing between the ionosphere and the magnetosphere which accelerate energetic charged particles that hit the upper atmosphere. At Saturn, these processes collisionally excite hydrogen, causing ultraviolet emission, and ionize the hydrogen, leading to H3+ infrared emission. Although the morphology of these aurorae is affected by changes in the solar wind, the source of the currents which produce them is a matter of debate. Recent models predict only weak emission away from the main auroral oval. Here we report images that show emission both poleward and equatorward of the main oval (separated by a region of low emission). The extensive polar emission is highly variable with time, and disappears when the main oval has a spiral morphology; this suggests that although the polar emission may be associated with minor increases in the dynamic pressure from the solar wind, it is not directly linked to strong magnetospheric compressions. This aurora appears to be unique to Saturn and cannot be explained using our current understanding of Saturn's magnetosphere. The equatorward arc of emission exists only on the nightside of the planet, and arises from internal magnetospheric processes that are currently unknown

Bilingualism in the world of health and illness

The movement of peoples across linguistic boundaries means the existence of individuals who speak, to a greater or lesser extent, more than one language. How such individuals have in the past and can in the present serve as mediators within the health care system is described and the need for closer attention to such resources stressed

Entrepreneurs and Labours: Chinese New Migrants in Cambodia

The scanning electron microscope (SEM) has unique capabilities for high resolution examination of surface structure and composition. Due to the resolution limits of optical inspection techniques, the semiconductor manufacturing industry has become a rapidly expanding field for SEM applications. As microcircuit groundrules (minimum feature sizes) continue to shrink below one micrometer non-optical measurement methods such as scanning electron microscopy must play an increasingly important role in the inspection of semiconductor device structures at various stages during their fabrication [1,2]. The measurement of structure dimensions such as circuit linewidths (or the spaces between lines) [3] and the measurement of circuit overlay [4] requires a minimum resolution of better than 1/10 groundrule dimensions. In fact, many manufacturing line managers state their resolution requirement as less than 1/20 groundrule dimensions, particularly during the development of a new process. Similarly, it is now apparent from device failure analysis that defects as small as 1/10 groundrule dimensions must also be detected and measured