997 resultados para Blue Island
Resumo:
This publication takes the form of a written version of my inaugural lecture, which was presented at Queen’s University Belfast on 10 March 2010. It is more personal and considerably more self-indulgent than would normally be acceptable in an article, with more of my own experiences and also my own references than would usually be considered proper. However, the bestowal of such a title as Professor of Island Geography is something of a marker of the maturity not just of myself but maybe also for island studies. After a section describing my path into island geography, the lecture deals with the negativities of islands and the seeming futility of studying them only then to identify a new or at least enhanced regard for islands as places with which to interact and to examine. Reference is made to islands throughout the world, but with some focus on the small islands off Ireland. The development of island studies as a discipline is then briefly described before the lecture concludes with reference to its title quotation on St Helena by considering that place’s islandness and how this affected/affects it in both the 17th and 21st centuries.
Resumo:
Using data from field introduction experiments with Gammarus spp. conducted in the rivers of a small island, commencing in 1949, with resampling in the 60s, 70s, 80s, 90s and finally in 2005, we aimed to examine the long-term interaction of the native freshwater amphipod Gammarus duebeni celticus with the introduced G. pulex. Using physico-chemical data from a 2005 island-wide survey, we also aimed to find what environmental factors could influence the distribution of the two species.
Resumo:
We present new photometric and spectroscopic observations of an unusual luminous blue variable (LBV) in NGC 3432, covering three major outbursts in 2008 October, 2009 April and 2009 November. Previously, this star experienced an outburst also in 2000 (known as SN 2000ch). During outbursts the star reached an absolute magnitude between -12.1 and -12.8. Its spectrum showed H, He I and Fe II lines with P-Cygni profiles during and soon after the eruptive phases, while only intermediate-width lines in pure emission (including He II lambda 4686) were visible during quiescence. The fast-evolving light curve soon after the outbursts, the quasi-modulated light curve, the peak magnitude and the overall spectral properties are consistent with multiple episodes of variability of an extremely active LBV. However, the widths of the spectral lines indicate unusually high wind velocities (1500-2800 km s-1), similar to those observed in Wolf-Rayet stars. Although modulated light curves are typical of LBVs during the S-Dor variability phase, the luminous maxima and the high frequency of outbursts are unexpected in S-Dor variables. Such extreme variability may be associated with repeated ejection episodes during a giant eruption of an LBV. Alternatively, it may be indicative of a high level of instability shortly preceding the core-collapse or due to interaction with a massive, binary companion. In this context, the variable in NGC 3432 shares some similarities with the famous stellar system HD 5980 in the Small Magellanic Cloud, which includes an erupting LBV and an early Wolf-Rayet star.
Resumo:
Azaspiracids are a class of recently discovered algae-derived shellfish toxins. Their distribution globally is on the increase with mussels being most widely implicated in azaspiracid-related food poisoning events. Evidence that these toxins were bound to proteins in contaminated mussels has been shown recently. In the present study characterization of these proteins in blue mussels, Mytilus edulis, was achieved using a range of advanced proteomics tools. Four proteins present only in the hepatopancreas of toxin-contaminated mussels sharing identity or homology with cathepsin D, superoxide dismutase, glutathione S-transferase Pi, and a bacterial flagellar protein have been characterized. Several of the proteins are known to be involved in self-defense mechanisms against xenobiotics or up-regulated in the presence of carcinogenic agents. These findings would suggest that azaspiracids should now be considered and evaluated as potential tumorigenic compounds. The presence of a bacterial protein only in contaminated mussels was an unexpected finding and requires further investigation. The proteins identified in this study should assist with development of urgently required processes for the rapid depuration of azaspiracid-contaminated shellfish. Moreover they may serve as early warning indicators of shellfish exposed to this family of toxins. Molecular & Cellular Proteomics 8: 1811-1822, 2009.
Resumo:
The discovery of a shallow water (