A jerk and a creep
“Hidden jerk in universal creep and aftershocks” may sound like the name of a Hollywood movie – and maybe some day it will be. But for now, it is exclusively the title chosen by Vikash Pandey at Krea University in India for a mathematical physics that involves earthquakes, avalanches, landslides and bamboo chopsticks. And, indirectly, spaghetti. It was published in Physical Review E. Allan Harvey brought it to Feedback’s attention.
Jerk, as most calculus students are amused to learn, is the technical word for the rate at which acceleration changes. In the haughty language of the trade, jerk is, as Feedback recalls it, “the third derivative of displacement, the second derivative of velocity and the first derivative of acceleration”.
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Creep, as most mechanical engineering students are pleased to discover, is a term for the tendency of a solid material to slowly change shape as it is being stressed.
Calculus, physics and engineering are a playground for people who like words. In his paper, Pandey proposes three new bits of jargon – “jerken”, “jerkity” and “the coefficient of jerkity” – each of which would take more space to define than Feedback is willing or able to donate.
The spaghetti is invoked in a study that Pandey cites, called . The final page of that study includes this memorable phrase: “the data for spaghetti appeared more scattered than those for the chopstick in Figure 3”. Explaining why and how that phrase is pertinent to this discussion of a jerk and a creep would, as with explaining the terms “jerken”, “jerkity” and “the coefficient of jerkity”, exceed the amount of space available here.
Lighting up
Physicists aren’t the only researchers hurtling in pursuit of a Theory of Everything: a simple, coherent story that explains many mysteries and that it is possible to verify through experiments.
A new study called “Nanoassemblies from the aqueous extract of roasted coffee beans modulate the behavioral and molecular effects of smoking withdrawal-induced anxiety in female rats” holds promise of realising the dream. It sews together many worlds of inquiry, almost defying any attempt to reduce the project down to a suitable, snappy summary.
The researchers behind the study, perhaps realising that people outside their fields might feel intimidated, a quietly charming graphical abstract (below). The artistically overwhelming power of the whole thing derives from the striking proximity – and similarity in size and colour – of the rat’s eye and the glowing tip of the cigarette. The rat’s head and the cigarette each float in space, compelling the reader’s attention.
How long you will live
Two denizens of the department of demography at the University of California, Berkeley, did some calculations about a popular life-and-death question. The question: how much should you trust mathematical recipes that predict how long a person will live?
Casey Breen and Nathan Seltzer explain their calculations, summarising them with the title . They used “eight machine learning algorithms using 35 sociodemographic predictors” to predict the lifespans of 130,000 people. They compared the predictions against those people’s actual birth and death dates listed in old census records.
They take from this a cheerily dour assessment: “We find that none of these algorithms are able to explain more than 1.5% of the variation in age of death. Our results point towards the unpredictability of mortality and underscore the challenges of using algorithms to predict major life outcomes.”
Do remind yourself that a few seconds ago, when you began to read this item, you were making the prediction that you would live long enough to read the item all the way through to its end.
Unfunnelled powers
Clive Teale confides having a trivial superpower that is rarely mentioned in polite or other company, maybe because it is rare. His confession adds to Feedback’s growing list of such superpowers.
Clive says: “Sadly now too old (at 79) to do this, when younger I could reliably demonstrate the ability to pour petrol from a gallon can into a motorbike tank without a funnel and without spillage.”
Tealean Petrol Pouring also belongs in the (as yet nonexistent) catalogue of Debatably Admirable Human Activities.
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