Seasonal cycle in vitamin A1/A2-based visual pigment composition during the life history of coho salmon (Oncorhynchus kisutch )

Microspectrophotometry of rod photoreceptors was used to follow variations in visual pigment vitamin A1/A2 ratio at various life history stages in coho salmon. Coho parr shifted their A1/A2 ratio seasonally with A2 increasing during winter and decreasing in summer. The cyclical pattern was statistically examined by a least-squares cosine model, fit to the 12-month data sets collected from different populations. A1/A2 ratio varied with temperature and day length. In 1+ (>12 month old) parr the A2 to A1 shift in spring coincided with smoltification, a metamorphic transition preceding seaward migration in salmonids. The coincidence of the shift from A2 to A1 with both the spring increase in temperature and day length, and with the timing of seaward migration presented a challenge for interpretation. Our data show a shift in A1/A2 ratio correlated with season, in both 0+

National Geographic : understand civil engineering differently

Our undergraduate civil engineering students have access to a rich and diverse bank of textual and graphical knowledge concerning their chosen profession. However, over a number of decades, commentators have raised concerns that our students have insufficient understanding of the role of civil engineering in society. Indeed, the call for universities to educate ‘global engineers’ emphasises the need for our students to be schooled in the humanities, in parallel with their core computational studies. Unfortunately, engineering students in particular, are not accustomed to regular exploratory reading. This paper considers the use of the National Geographic magazine as a means to ignite our students’ curiosity with the world around them. The results from a pilot study and a content analysis of a number of editions from over a decade shows that this periodical regularly carries themes directly concerning the impact of civil engineering in society, be it political , financial environmental , social or ecological