Scotland the Brave

    

Scotland is voting today on whether, after 307 years, to leave the United Kingdom and follow the uncertain path of independence. It seems a good moment to salute Scottish scientists. Three (of many) are shown above:

Mohr’s burette

The burette, an important volumetric tool, was invented by Karl Friedrich Mohr somewhere around the middle of the 19th century. There had been other devices carrying the name “burette,” but they required pouring. Mohr introduced a rubber tube with a clamp that allowed the gradual drop-by-drop flow needed for titration (the clamp was later replaced by a tap). Mohr’s 1855 book on titration, which illustrated the device, helped it to become the key item of analytical equipment it still (in spite of more modern digital devices) is today. Thanks, Karl!

Once again, a Google ngram summarises the history, with the word “burette” rapidly gaining popularity from 1855, but being replaced by the word for the process, which itself faded after 1960 – perhaps because of the growth of other kinds of science.

Emission spectrum scarves

Above is one of the nifty atomic emission spectrum scarves made by Becky Stern. An emission spectrum is the pattern of light colours produced by heated atoms, and the emission spectra of different chemical elements act as a kind of visual “fingerprint.” There’s something wonderfully geeky about putting one on a scarf – and they look great too.

Becky Stern no longer seems to sell these scarves, but has posted patterns for making your own. More pictures here.

Dendrogramma, a strange new genus

A recent paper in PLoS ONE (by Jean Just, Reinhardt Møbjerg Kristensen, and Jørgen Olesen) reports the new species Dendrogramma discoides (marked with asterisks in the image from the paper above) and Dendrogramma enigmatica (unmarked above). These species were found in waters off south-east Australia.

Specimens from this new genus were collected in 1986, and preserved in formaldehyde. This is a pity, because the organisms have not been found again, and the formaldehyde has destroyed their DNA.

DNA analysis would have been useful to work out in which animal phylum to place Dendrogramma. The usual candidates (left to right above) are Porifera (sponges), Ctenophora (comb jellies), Cnidaria (jellyfish), and the Bilateria – such as Echinodermata (which are bilaterally symmetrical as larvae) or Chordata.

The fascinating Dendrogramma specimens are not bilaterally symmetrical, and are not sponges. They lack specialised features of the Ctenophora and Cnidaria, such as Cnidarian stinging cells. So what are they? It seems likely that either a new phylum has to be defined; or that Dendrogramma must be placed in a restored Coelenterata (a former phylum which once contained the Ctenophora and Cnidaria); or that the boundaries of Ctenophora or Cnidaria need to be extended – but without DNA, the decision is difficult.

Ebola #3

Updating Ebola news, the map above shows the current situation in West Africa. The graph below shows cases to date (with LOESS smoothing).

Below is an estimate of the new cases per day (calculated from the smoothed data). The acceleration of the disease appears to be continuing, which is very disturbing. See the WHO and CDC websites for more information.