The agitated detective barks, “I need that DNA now. There’s a killer on the loose, and I have to know if we’ve got him in custody. I don’t give a damn how busy you are . . . ” We’ve all been there, on the edge of the couch, watching a cop show on TV and hoping that the magic of DNA testing will give a clear answer to the question “DidHeDoIt?” And indeed, DNA fingerprinting, more accurately ‘DNA profiling’, has transformed crimefighting.… Read the rest “DNA profiling I”
Gel electrophoretic separation of DNA fragments containing Variable Numbers of Tandem Repeats. Each vertical lane contains one DNA sample. PCR-amplified fragments have been labeled, with different probes having different fluorescent labels. The red bands are internal calibration markers. The positions of the bands reflect their different mobilities, which in turn reflect their lengths (larger fragments move more slowly in electrophoresis). Capillary electrophoresis and automatic recording are used today instead of gel electrophoresis.
DNA profiling resulted from the convergence of scientific curiosity, technological advances, and the desire to provide a social benefit.… Read the rest “DNA profiling II”
I first posted “The Inefficiency of Humans” in January 2017. It’s about the reasons that our energy metabolism provides only about 20-25% of the energy we consume as food for muscular work. I referred to this as our “inefficiency”, although it isn’t really that. The explanation and conclusions remain largely unchanged, but since then I’ve learned more about how energy metabolism is measured, so I’ve rewritten the post as this 2.0 version. Much of the original is unchanged.… Read the rest “The Inefficiency of Humans”
Laphroiag distillery on Islay. A group of international whisky tourists, an important source of revenue for malt distilleries in Scotland, is being shown around. The pagoda chimney is a common feature.
There is a good deal of science, and art, associated with single malt Scotch whisky (there’s no “e” in whisky in Scotland). Many of us know bits and pieces about it and how it’s made. But there may be readers, who, like me, are fans but also interested to learn more.… Read the rest “Single malt Scotch Whisky 101”
A death in Minnesota
The young man arrived in the emergency room in Minneapolis, Minnesota in acute distress, with a fever, rapid deep breathing, and a racing heart. As reported in 2018, doctors couldn’t initially identify the cause of his problem (1). His breath had twice the normal level of carbon dioxide, and that level kept going up. His fever also kept increasing, despite the doctors’ frantic efforts to stabilize him. Forty-five minutes after admission the muscles in his body violently seized up, rigor mortis, but in a body not yet dead.… Read the rest “How DNP (dinitrophenol) kills you”
Rooftop air conditioning units, midtown, Manhattan. Imagery Google Maps, ©2019 Bluesky, Maxar Technologies, Sanborn, USDA Farm Service Agency, Map data ©2019
A hot day in New York City
People who were there will remember Saturday, July 20, 2019, as a really hot day in New York City. Although it was not the hottest day on record, the temperature at Kennedy airport reached 96ºF (36ºC). On the street at Union Square in Manhattan, a large thermometer (known as BAT, the “Big-Ass Thermometer”) registered a murderous 110ºF.… Read the rest “Is Air Conditioning Going to Become Futile?”
Early Press. Accreditation: Daniel Chodowiecki [Public domain]
This post is something original, in that it’s not original: it’s a link to an intriguing article published a few years ago, which came to my attention on Flipboard. The article was published in 2013 in The Atlantic, and was a compilation of the 50 “innovations that have done the most to shape the nature of modern life”(since the wheel). I sent emails which included an abridged version of the article to a number of people.… Read the rest “The Greatest Innovations and Breakthroughs”
Ponte Morandi, Genoa. The tower on the left, and the adjacent roadway, collapsed on August 14, 2018. Picture attribution: Salvatore1991
A terrible tragedy occurred in Genoa, Italy on August 14, 2018. A suspension bridge in that city, part of the A10 motorway, collapsed into the bed of the Polcevera River, 150 feet below. Forty-three people who were driving over the bridge were killed.
The cable-stayed bridge
The bridge in Genoa, called the Ponte Morandi after its designer, Riccardo Morandi, was opened in 1967.… Read the rest “The Death of Ponte Morandi”
Necora puber. Photograph: Hans Hillewaert
Cancer is one our most feared diseases, so it isn’t surprising that we notice when it is linked to other parts of our lives. And it’s also not surprising that stories which sound plausible, but which may or may not be supported by evidence, or which are misunderstood, become part of our culture. Three such stories are, that we are in an epidemic of cancer, that vitamin C is a useful anti-cancer agent, and that an abortion increases a woman’s risk of later breast cancer.… Read the rest “Three Cancer Myths”
The Waste-to-Energy plant “Amager Bakke” in Copenhagen, Denmark. Photo credit Niels Quist/Alamy stock photos.
Most people do not enjoy talking, or reading, about garbage. For one thing, it’s boring. But it’s also disturbing: garbage imposes great costs on our economy and our society. The biggest problem is simply the amount of garbage we produce. For example, in 2015, two kilograms (4.4 pounds) of Municipal Solid Waste was generated per citizen of the USA every day (MSW is the fancy name for garbage).… Read the rest “What Should We Do About Garbage? A Burning Question”