| 1. |
- Heywood, I., et al.
(författare)
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Inflation of 430-parsec bipolar radio bubbles in the Galactic Centre by an energetic event
- 2019
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 573:7773, s. 235-237
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Tidskriftsartikel (refereegranskat)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.
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| 2. |
- Andersson, L-O, et al.
(författare)
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A new neutron beam facility
- 2004
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Ingår i: Proc. of the 9th European Particle Accelerator Conference.
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Konferensbidrag (refereegranskat)
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| 3. |
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| 4. |
- Ciavola, G., et al.
(författare)
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Status report of the multipurpose superconducting electron cyclotron resonance ion source
- 2008
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Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 79:2, s. 02A326-
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Tidskriftsartikel (refereegranskat)abstract
- Intense heavy ion beam production with electron cyclotron resonance (ECR) ion sources is a common requirement for many of the accelerators under construction in Europe and elsewhere. An average increase of about one order of magnitude per decade in the performance of ECR ion sources was obtained up to now since the time of pioneering experiment of R. Geller at CEA, Grenoble, and this trend is not deemed to get the saturation at least in the next decade, according to the increased availability of powerful magnets and microwave generators. Electron density above 1013 cm(-3) and very high current of multiply charged ions are expected with the use of 28 GHz microwave heating and of an adequate plasma trap, with a B-minimum shape, according to the high B mode concept [S. Gammino and G. Ciavola, Plasma Sources Sci. Technol. 5, 19 (1996)]. The MS-ECRIS ion source has been designed following this concept and its construction is underway at GSI, Darmstadt. The project is the result of the cooperation of nine European institutions with the partial funding of EU through the sixth Framework Programme. The contribution of different institutions has permitted to build in 2006-2007 each component at high level of expertise. The description of the major components will be given in the following with a view on the planning of the assembly and commissioning phase to be carried out in fall 2007. An outline of the experiments to be done with the MS-ECRIS source in the next two years will be presented.
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| 5. |
- Moore, C.D., et al.
(författare)
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Development and preliminary validation of a scale to measure self-efficacy in seeking mental health care (SE-SMHC)
- 2015
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Ingår i: SpringerPlus. - : Springer Science and Business Media LLC. - 2193-1801. ; 4:1
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Tidskriftsartikel (refereegranskat)abstract
- © 2015, Moore et al. Purpose: Globally, the prevalence of mental illness is on the rise, although few people with psychiatric disorders actually seek mental health care. One under-researched factor that may impact help-seeking behavior from health care professionals is self-efficacy. This research presents the development and validation of the Self-Efficacy to Seek Mental Health Care (SE-SMHC) scale, a nine item-self report measure. It was hypothesized that self-efficacy for seeking mental health care would be positively associated with higher rates of self-reported help-seeking behavior and higher rates of advising others in distress to access mental health treatment. Methods: A randomized population sample of 977 South Africans completed the SE-SMHC as part of a larger study on barriers to health care for mental illness. SE-SMHC data were subjected to principal component analysis, and data from the larger study were utilized to test the hypotheses. Results: Two latent factors emerged from the oblique rotation and accounted for 70% of the variance: SE-KNOW (confidence in one’s ability to know how to successfully interface with mental health care systems) and SE-COPE (confidence in one’s ability to cope with the consequences of seeking care). Cronbach alphas for both subscales were 0.87 and for the total scale score was 0.93. Both hypotheses were confirmed suggesting evidence of the scale’s validity. Conclusions: This data suggests that the SE-SMHC demonstrates good psychometric characteristics and may be a useful research tool and screening instrument for targeted interventions.
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| 6. |
- van Rooyen, Ronél, et al.
(författare)
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Construction of cellobiose-growing and fermenting Saccharomyces cerevisiae strains
- 2005
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Ingår i: Journal of Biotechnology. - : Elsevier BV. - 1873-4863 .- 0168-1656. ; 120:3, s. 284-295
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Tidskriftsartikel (refereegranskat)abstract
- beta-Glucosidase genes of fungal origins were isolated and heterologously expressed in Saccharomyces cerevisiae to enable growth on the disaccharide, cellobiose. To promote secretion of the beta-glucosidases, the genes were fused to the secretion signal of the Trichoderma reesei xyn2 gene and constitutively expressed from a multi-copy yeast expression vector under transcriptional control of the S. cerevisiae PGK1 promoter and terminator. The resulting recombinant enzymes were characterized with respect to pH and temperature optimum, as well as kinetic properties. The two most promising enzymes, BGL1 from Saccharomycopsis fibuligera and Bg1A from Aspergillus kawachii, were anchored to the yeast cell surface by fusing the mature proteins to the alpha-agglutinin (AG alpha 1) or cell wall protein 2 (Cwp2) peptides. The maximum specific growth rates (mu(max)) of the recombinant S. cerevisiae strains were determined in batch cultivation. S. cerevisiae secreting the recombinant S. fibuligera BGL1 enzyme sustained growth aerobically and anaerobically, in minimal medium containing 5 g L-1 cellobiose at 0.23 h(-1) (compared to 0.29 h(-1) on glucose) and 0.18 h(-1) (compared to 0.25 h(-1) on glucose), respectively. Substrate consumption and product formation were determined to evaluate product yields in glucose and cellobiose. (c) 2005 Elsevier B.V. All rights reserved.
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