Highly unpleasant and negative are the raw, uncomposted, intense smells that emanate from concentrated animal feeding operations, or CAFOs, which confine and raise large numbers of animals—hundreds, thousands, hundreds of thousands—in a small area, and have come to dominate modern meat and dairy production over the last few decades. They accumulate huge quantities of excrement that can be smelled from miles away. I live in central California and pass by the Harris cattle ranch on Interstate 5 near Coalinga whenever I drive between San Francisco and Los Angeles. Even with the car windows closed, I can smell it long before I see it. Tens of thousands of beef cattle are confined there, each animal generating some 65 pounds of urine and excrement a day. Today’s formulated feeds usually supply more nitrogen than the animals would obtain from their natural diet of plants, so their excrement is especially rich in the most offensive volatiles, the branched acids, cresol, skatole, ammonia, and amines.
Those pushing herd immunity want people to think that it could be the route out of the Covid crisis, when, in fact, it’s more likely to prolong the nightmare. Just think for a second what such a strategy would actually look like. We would end up in a situation like that currently being faced in parts of Belgium — hospitals are under such pressure that drugs are being rationed and doctors have been issued with guidance on who is eligible for treatment. All this is before we consider what effect it would have on NHS staff who would also become unwell and unable to tend to the sick.
When a crew member fell seriously ill, the vessel returned to port, and almost everyone was tested for the virus again. The before-and-after results for 120 of the crew members were made available to Bloom and colleagues, who published a study about them in The Journal of Clinical Microbiology in August. In addition to the P.C.R. tests, the pre-voyage screenings also looked for neutralizing antibodies, or proteins generated by the immune system after exposure to the virus, which suggest that a person has been infected previously. Three crew members, it turned out, had those antibodies at the start of the trip. Of the 117 crew members who did not, 103 tested positive for the virus when they got back to shore — an 88 percent infection rate. If you were to randomly select three names from the ship’s manifest, the odds that all three would have tested negative are about 0.2 percent. Yet all three sailors with antibodies were spared.
The Ising model
The mathematical key to cracking “phase transitions” debuted exactly 100 years ago, and it has transformed the natural sciences. The Ising model, as it’s known, was initially proposed as a cartoon picture of magnets. It’s now so commonly used as a simple model of physical systems that physicists liken it to the fruit fly, biology’s model organism. A recently published textbook deemed the Ising model “the system that can be used to model virtually every interesting thermodynamic phenomenon.”
A weekend post. Who knows might be able to solve one of these.
1. The Collatz Conjecture
Earlier this month, news broke of progress on this 82-year-old question, thanks to prolific mathematician Terence Tao. And while the story of Tao’s breakthrough is good news, the problem isn’t fully solved.
A refresher on the Collatz Conjecture: It’s all about that function f(n), shown above, which takes even numbers and cuts them in half, while odd numbers get tripled and then added to 1. Take any natural number, apply f, then apply f again and again. You eventually land on 1, for every number we’ve ever checked. The Conjecture is that this is true for all natural numbers.
Recently, randomness has even made the news: Apparently there’s hidden order in random surfaces, and we may be close to seeing a quantum computer generate ultimate randomness. This latter quest for perfect randomness is important because randomness brings unpredictability, and all non-quantum attempts to achieve it have the hidden flaw of being generated by algorithmic methods which can, theoretically, be deciphered. In this Insights column, we will explore how we can create randomness and defeat it in everyday activities, before soaring to philosophical heights in debating what randomness really is.
As both a professor of science education, with research expertise in evolutionary biology, and a priest in the Church of England, I believe that we need to rethink the way we teach evolution. I’ve spent 30 years teaching evolution to school students, undergraduates and teachers in training. It is clear to me that the way the subject is typically taught in schools can force religious children to choose between their faith and evolution. This is as true for Christian students as it is for Muslims, Orthodox Jews and members of other religions.
Generating an image of a black hole is a paradox. A black hole is invisible by nature – it emits no matter that we can measure. So what we see in the image is actually its event horizon. The bright ring is not a physical ring – it’s light coming from matter orbiting the black hole, which is so extremely warped that light itself is bending. There are black holes at the centre of every galaxy – some which sing, some which whir along quietly – and now that we’ve created images of one, it’s possible that we can continue to image more black holes, and even other kinds of cosmic matter.
Remarkably, What Is Life? appeared at the height of World War Two. Schrödinger had fled his native Austria to escape the Nazis and, after a brief sojourn in Oxford, settled in Dublin at the invitation of the prime minister, Éamon de Valera, accompanied by both his wife and mistress. Ireland was a neutral country, so Schrödinger felt free to pursue his academic work, unlike many of his scientific colleagues who assisted the Allies’ war effort. Schrödinger was best known as one of the founders of quantum mechanics, the most successful scientific theory ever. It explained at a stroke the properties of atoms, molecules, subatomic particles, nuclear reactions and the stability of stars. In practical terms, quantum mechanics has given us the laser, the transistor and the superconductor. For de Valera, Schrödinger was quite a catch.
In the end, I keep coming back to the question of how you know a weapon works if you cannot test it. (Or, for that matter, how testing ever established reliability since it destroyed the object whose reliability it demonstrated.) Who am I to question the judgment of the physicists who have spent decades honing their expert knowledge of this arcane field? Still, I keep thinking of a conversation I had in 1995 with a senior weapons designer, now retired, who told me that an inexperienced designer with a code is like a drunk driver, wrongly convinced of their excellent judgment. And I cannot help but notice a 2012 Department of Energy report complaining that National Ignition Facility shots were not producing the energy levels predicted by simulation codes. Nor, in 2015, has the National Ignition Facility met its former director’s prediction of reaching ignition—getting more energy out than was put in—by late 2012.