ABSTRACT
The Galactic Centre contains a supermassive black hole with a mass of four million Suns1 within an environment that differs markedly from that of the Galactic disk. Although the black hole is essentially quiescent in the broader context of active galactic nuclei, X-ray observations have provided evidence for energetic outbursts from its surroundings2. Also, although the levels of star formation in the Galactic Centre have been approximately constant over the past few hundred million years, there is evidence of increased short-duration bursts3, strongly influenced by the interaction of the black hole with the enhanced gas density present within the ring-like central molecular zone4 at Galactic longitude |l| < 0.7 degrees and latitude |b| < 0.2 degrees. The inner 200-parsec region is characterized by large amounts of warm molecular gas5, a high cosmic-ray ionization rate6, unusual gas chemistry, enhanced synchrotron emission7,8, and a multitude of radio-emitting magnetized filaments9, the origin of which has not been established. Here we report radio imaging that reveals a bipolar bubble structure, with an overall span of 1 degree by 3 degrees (140 parsecs × 430 parsecs), extending above and below the Galactic plane and apparently associated with the Galactic Centre. The structure is edge-brightened and bounded, with symmetry implying creation by an energetic event in the Galactic Centre. We estimate the age of the bubbles to be a few million years, with a total energy of 7 × 1052 ergs. We postulate that the progenitor event was a major contributor to the increased cosmic-ray density in the Galactic Centre, and is in turn the principal source of the relativistic particles required to power the synchrotron emission of the radio filaments within and in the vicinity of the bubble cavities.
ABSTRACT
The number of patients admitted to Intensive Care Units with organophosphate poisoning are a source of concern. Also distressing is the fact that organophosphates are often being used in suicide attempts. It is therefore imperative that the nurse acquires and retains the necessary skills for caring for these patients. The course of this condition and the associated nursing care is discussed at length in this article in an attempt to equip you with these skills.
Subject(s)
Insecticides/poisoning , Organophosphorus Compounds , Critical Care , Humans , Insecticides/pharmacology , Poisoning/diagnosis , Poisoning/nursingABSTRACT
Dentistry is a relatively new occupation for females in the RSA. Female dentists have particularly increased since 1975. Currently, approximately 11.4 per cent of the dental labour market consists of female dentists. Present student intakes indicate that the number of female dentists will increase to approximately 20.9 per cent within the next five years. Personal and professional characteristics of female dentists were determined by means of a survey of 55 female dentists on the Register of the South African Medical and Dental Council. Replies were received from 36 of the women, representing a response rate of 65 per cent. Female dentists are relatively young, married, their spouse mainly also in a professional occupation, and have at least two children. Factors which may have an special impact on professional activities include marital conflict due to interpersonal relationships, interaction of the mother and wife role on occupation, and lapse in service due to pregnancy. The results of this study indicate that female dentists are in general professionally and intellectually active in service. Female dentists are more inclined to private practice. Unmarried females are, as expected, professionally more active on a full-time basis in comparison to married females which are proportionally more active on a part-time basis. The respondents are mostly of the opinion that the dental profession provides sufficient occupational satisfaction to justify a professional identity for female dentists.
Subject(s)
Dentists, Women , Adult , Female , Humans , Middle Aged , South AfricaABSTRACT
In our experience, accidents involving all-terrain vehicles are an increasingly frequent cause of brain injury in children. The risk associated with operation of these vehicles is not fully appreciated and should be better publicized. We believe that it is possible to delineate several steps that could significantly reduce the risk to the pediatric population without curtailing the recreation altogether. Although construction design has promised to produce safer vehicles, our experience has shown that extreme injury is still possible with the newer four-wheel machine.
