Science News Roundup : 2018-01-17

Science News Roundup : 2018-01-17

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Northern Pole of Cold records -62 °C

The 2017-18 northern hemispheric winter1 has been uncharacteristically harsh. Bangladesh has recorded its coldest temperature ever on Jan 8, 2018. Florida and the Sahara desert have seen snowfall. And a small hamlet in Siberian Russia has (almost) broken its own record for the coldest temperature ever recorded in an inhabited place.

Oymyakon is a small hamlet in the Yakutia region of Siberia, Russia. It has a population of only 500, and is one of the northern Poles of Cold, places on Earth that record the lowest air temperatures. The coldest ever temperature in the northern hemisphere was recorded here Feb 6, 1933 when the mercury dipped to an incredible -67.7 °C. To put this into perspective, the coldest temperatures at the North Pole are somewhere in the vicinity of -50 °C.

A few days back, Oymyakon nearly broke its own record when a digital thermometer, installed as a tourist attraction, froze and stopped working, showing a temperature of -62 °C. Local residents reported that the mercury kept falling, eventually coming perilously close to -67 °C. However, as far as I am aware, no documented evidence of this exists. Nevertheless, it is a clear indication of the steady drop in temperatures in winter in the northern hemisphere over the past three years, and is a dreaded indication of the malevolent and complex effects of global warming.

Sources :

Telegraph UK

Independent UK

Siberian Times

Florida winter

Coldest temperature ever in Bangladesh

Sahara snowfall

Black Death was spread by dirty humans, not rats

The Black Death was one of the most devastating plague pandemics in human history. In all, anywhere between 75-200 million people died in Europe and Asia. The peak period was between 1346-1353 in Europe. The plague is caused by the bacteria Yersinia pestis and is generally believed to be spread through rats and fleas. The plague has three forms: bubonic, in which the bacteria enters the human body and attacks the lymph nodes; and pneumonic, in which the bacteria enters via the airways and attacks the lungs, are the most common.

Once entering the human body via the skin, the bacteria causes lymph nodes to swell and blacken, thus earning the plague its name. More than a third of Europe’s population and nearly a quarter of the entire human population perished in this plague. It had far-reaching consequences for both European and world history.

For centuries, it was believed that Oriental rat fleas living on black rats were the primary method of propagation of the bacteria. However, a recent study published in the journal PNAS have disputed this claim. They counter-claim that human ectoparasites, that is, human body lice and fleas, were the vectors for the Yersinia bacteria. They show this by carrying out simulations of the spread of the infection using mortality data from nine cities in Europe. They set up three possible scenarios of plague propagation :

  • Transmission via human fleas and body lice (bubonic)
  • Transmission via rat fleas (bubonic)
  • Transmission between humans (pneumonic)

Fit of three models of plague transmission to mortality during Second Pandemic outbreaks. The observed human mortality data (black dots) and the fit (mean and 95% credible interval) of three models for plague transmission [human ectoparasite (red), pneumonic (blue), and rat–flea (green)] for nine plague outbreaks: (A) Givry, France (1348), (B) Florence, Italy (1400), (C) Barcelona, Spain (1490), (D) London, England (1563), (E) Eyam, England (1665), (F) Gdansk, Poland (1709), (G) Stockholm, Sweden (1710), (H) Moscow, Russia (1772), and (I) Island of Malta, Malta (1813).
Now, using Bayesian inference on available data, they find that alternative #1 has the highest probability of occurring in seven of the nine datasets (cities) they used. In simpler terms, the reason why the Black Death spread so far and wide is probably because people in those times didn’t bathe as often.

Sources :

BBC

Science Alert

Telegraph UK

Original PNAS paper

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Footnotes

  1. Well, in Australia, South Africa and Argentina, among many other nations, it is summer now. Easy to forget.

3 Replies to “Science News Roundup : 2018-01-17”

  1. The black death fact sounds astonishing. There are many areas where water is very scarce and due to tropical weather infection spreads very quickly. Yet we don’t see too many cases in such areas of India or Africa. On the other hand, Europe goes through dark winter, chance of getting body lices must be lower if people cannot take bath. The population is also significatly lower than dark or brown continents. Still it was London that was ‘plagued’, not Purulia. Any thoughts?

  2. Thank you for the question PB. Yes, quite a few thoughts, in fact. 🙂

    If one looked at the spread of the plague in Europe between 1346-1353 (https://en.wikipedia.org/wiki/Black_Death), then one would be astonished at the speed at which it spreads. Europe, though the smallest continent, is hardly small, and given the technology of the 14th century, for the plague to spread from Constantinople in 1347 to the northern tip of Norway and Sweden in 1353 is absolutely incredible.

    On the question of hygiene : tropical countries have a significant advantage over temperate ones in terms of personal hygiene. In colder climes, it is quite possible to live for months, if not years, without bathing. That is completely impossible in hot and humid countries such as India. Also, the Hindu and Muslim faiths both lay great stress on bodily hygiene and ritual washing and cleaning. For Hindus, bathing and washing before worship is an absolute must. For Muslims, ablutions after all possible bodily functions and before prayer is an absolute must. Perhaps that is why one does not hear about a Black Death in parts where Hindu or Muslim populations dominate. In fact, the Black Death is said to have originated in the dry Central Asian plains, a place where water is scarce.

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