Een slepende ziekte: de Vlaamse kijk op de Congolezen

Ruddy Doom dissecteert in deze historische analyse de manier waarop Vlamingen op de Congolezen (neer)kijken

Gamma-ray line emission from Al-26 produced by Wolf-Rayet stars

The recent satellite observations of the 1.8 MeV line from the decay of Al-26 has given a new impetus to the study of the nucleosynthesis of Al-26. The production and ejection of Al-26 by massive mass-losing stars (Of and WR stars) is discussed in the light of recent stellar models. The longitude distribution of the Al-26 gamma ray line emission produced by the galactic collection of WR stars is derived based on various estimates of their radial distribution. This longitude profile provides: (1) a specific signature of massive stars on the background of other potential Al-26 sources, as novae, supernovae, certain red giants and possibly AGB stars; and (2) a possible tool to improve the data analysis of the HEAO 3 and SMM experiments

Crassicauda boopis in a fin whale (Balaenoptera physalus) ship-struck in the eastern North Atlantic Ocean

On 9 November 2015, a juvenile male fin whale of 11·60 m length was observed on the bulb of a merchant vessel in the Channel Terneuzen – Ghent (The Netherlands – Belgium). A severe parasitosis was present in the right heart ventricle and caudal caval vein. Parasites were identified as Crassicauda boopis based on macroscopic and microscopic observations. The sequence of the 18S rRNA gene obtained from the parasite samples was 100% similar to the sequence of the 18S rRNA gene from Crassicauda magna available on GenBank. While adults of C. boopis and C. magna are morphologically distinct and found at different locations in the body, the molecular analysis of the 18S rRNA gene seems insufficient for reliable species identification. Although numerous C. boopis were found, the cause of death was identified as due to the collision with the ship, as suggested by the presence of a large haematoma, and the absence of evidence of renal failure. The young age of this whale and the absence of severe chronic reaction may suggest that the infestation was not yet at an advanced chronic stage

The external ear canal of cetaceans, vestigial or not?

Cetaceans descend from land mammals. Consequently, their hearing apparatus basically consists of the same anatomical components. Whales, as land mammals, feature an outer, middle and inner ear. However, these structures show strong evolutionary adaptations to underwater hearing. In addition, other morphological elements, such as the mandibles and the associated acoustic fat, have acquired an acoustical function in the propagation of sound waves to the middle ear. The original function of other structures such as the external auditory canal is therefore questioned. How cetaceans hear is not yet fully understood. However, it is essential to clarify this in order to assess the impact of anthropogenic underwater sound, since high-energy underwater sound may lead to physical trauma and hearing loss, physiological stress and behavioral changes. In this study, the external ear canal of a white-beaked dolphin (Lagenorhynchus albirostris) and a common minke whale (Balaenoptera acutorostrata) are described and compared based on histological cross sections. These external ear canals seemed rudimentary, with a small to absent lumen. However, the blood supply, well-developed muscles, active glands and numerous nerve fibres could indicate some functionality. Moreover, the presence of numerous structures with a morphological similarity to lamellar corpuscles also could advert to a functional structure. Although the function of these potential mechanoreceptors is not known, they could play a part in pressure perception in these diving mammals