#Introduction I'm a postdoc working at the Structure and Motion Lab at the Royal Veterinary College. British-Canadian, husband and father of four amazing children. I'm into comparative #biomechanics and #robotics, building a career at the interface of the two. Also looking for ways to contribute to #greenenergy. #DisabledinSTEM with #adhd and anxiety. Tell me about your #coolbugs #coolrobots and #weirdanimals
As a #control #systems #engineer who works in #robotics, I sometimes see people blindly use a #PID controller design (without justification) and then attempt to tune it by trial-and-error. So, I made this little tutorial for my students: https://github.com/botprof/PID-101. Maybe others will find it useful too? There are lots of ways to tackle controller design, but I like this approach for cases when PID is the right choice.
LOOOOOOOK!! That asteroid grain I took to the UK (the one where I nearly couldn't board the plane due to having the wrong seat type reserved for the Hayabusa2 model)?
It's now on display at the London Science Museum!
I totally brought it there. Me! Yay!
My favorite paper that I've read this year — a look at how confusion between inferential uncertainty and outcome variability creates all sorts of problems — is now out in PNAS.
Here's the paper: https://www.pnas.org/doi/abs/10.1073/pnas.2302491120
Here's the thread I wrote about the preprint last April: https://fediscience.org/@ct_bergstrom/110267907188002904
I just read the best paper I've seen yet this year, Sam Zhang's work on confusion between inferential uncertainty and outcome variability.
In the context of a trial or experiment, inferential uncertainty refers to our statistical confidence that two groups are different. Outcome variability refers to how much variation there is in individual outcomes within a single group.
IMO confusion about this is ubiquitous in biomedical science.
Here's the paper: https://osf.io/preprints/socarxiv/5tcgs/
In their #JEB100 Review, Ijspeert & Daley discuss how comparative animal studies and neuromechanical modeling have revealed diversity in the integration of feedback and feedforward control, related to body size, mechanical stability, time to locomotor maturity and movement speed
Now published! Brazilian PhD student Mauro Lacerda led our efforts to reconstruct how early #theropod #dinosaur pelvic appendages evolved, focusing on megalosauroids. Big open access paper: https://royalsocietypublishing.org/doi/10.1098/rsos.230481
To celebrate of the work of the scientists who publish in the Company of Biologists journals, we are currently planting a tree in the Forest of Biologists for each paper that we publish. We recently celebrated Dowd & Somero's JEB paper https://journals.biologists.com/jeb/article/226/15/jeb246033/324982
by planting a small-leaved lime (Tilia cordata) https://forest.biologists.com/landscape/?doi=10.1242%2Fjeb.246033&tgl=1 to at our forest at the Woodland Trust's Young People's forest https://www.woodlandtrust.org.uk/visiting-woods/woods/young-peoples-forest-at-mead/
Not everything implemented yet, but you can:
import cameras + image planes
Apply rigid body transforms to objects
Create axes w/ locators
Calculate relative motion between objects.
Youtube video run through here: https://youtu.be/zRH4XBChrgA
"the sheer size and brutal power of the capitalist behemoth is bewildering"
It is - from one perspective. But there is another.
I know I'm odd, having for many years been immersed in history - not the dates and battles and kings and queens kind, but the how people thought and felt and looked at the world and won their livelihood kind of history.
So I was thinking about an old oral history study - 'Quarry Roughs' by Raphael Samuel - that is about how part of an Oxfordshire UK village, right up to the First World War, refused to get into wage labour, and instead carried on getting a living from growing and grazing on the remaining common land, poaching and collecting seasonal wild foods (literally 'hunting and gathering'), and doing casual work for cash in hand. Just the sort of mixture, in fact, that #graeberandwengrow see as typical of human life for thousands of years (as opposed to agriculture suddenly replacing hunter-gatherers). But this was in the very heart of British Imperialism at its absolute height.
So I've been wondering if capitalism really is that strong. Do we naturally take to its exchange relations, wage labour, etc, in our family life, with our friends and neighbours and local communities? Or is our 'natural' inclination to freely share and co-operate?
But apart from this businesses are everywhere, aren't they?
I agree – but ‘the private sector’ is not one thing. Mainly, it’s small businesses (around 95% of all UK businesses have less than 10 employees, and 75% have no employees at all); it’s also anti-capitalist but market-oriented organisations like co-operatives and social enterprises; and it’s civil society, much of which also trades. Oh, and comparatively few middle-sized, and even fewer enormous ‘shareholder value’ capitalist behemoths.
And here’s the thing: most small business is not really ‘capitalist’ at all – it is not very different from traders, artisans, musicians, etc, that worked in pre-capitalist economic systems. In the small business development/investment world, practitioners always try to distinguish ‘growth’ and ‘lifestyle’ businesses – they are looking for the actually rare ‘growth businesses’ that will repay their input. But most small businesses are in fact ‘lifestyle businesses’ – people that want to make a living doing something they love, and hopefully are good at, that serves and is pretty integrated in a local (or online) community, and has no desire to either grow too big or make vast fortunes. Such businesses would be sustainable in an economy where money actually had the ‘means of exchange’ function most people think it has. Many of these 'lifestyle businesses' are really rejecting capitalism - the discipline of wage-labour, the elevation of profit above enjoying your work, your life - just as surely as the 'Quarry Roughs' consciously rejected it.
Yes - there are a few thousand 'shareholder value' capitalist behemoths in the world, and they own many politicians - and they have in many places succeeded in marketising our social lives with their mass media and cloned high streets - and our own bodies with their 'you don't look right but this product will fix you' propaganda - but everywhere, many of us see through it, refuse it - and we have proven - and are proving ourselves strong too.
#introduction Hi there! 👋 I'm a PhD Student at the Structure and Motion Lab in Royal Veterinary College and Moazen's Lab at University College London. I’m into the fascinating world of #biomechanics and #evolution in animals. When I'm not deeply engrossed in my research, you can find me advocating for #conservation and #AnimalWelfare issues. Feel free to say hello if you share the same passion in nature and science! 🌿🎨 #phdstudent #researcher #scientist #biomechanics #evolutionarybiology
The results are in! Although a majority said (a), for this particular setup, (b) jumps higher.
This is NOT a general rule in biological jumpers, and is particular to how we've set up the problem (notably, no force-velocity relationship) #biomechanics
All that matters is the amount of work done by the muscle. Since there is no force-velocity relationship, the work done is proportional to the shortening distance. Case (b) wins because the larger in-lever allows the muscle to shorten more
We have an intuition that (a) should be better because biological jumpers look like that. But this is to accommodate power-velocity relationships in muscle, which this setup doesn't have.
My intuition was initially drawn to (c), but the physics clearly show (b) as the winner here. A good reminder to check model assumptions!
If anyone has a good real-world example analogous to this setup, let me know! Force-velocity is pervasive, though
Which will jump higher?
Is it better to jump with a long foot or short foot?
The cases below only differ by whether the in-lever or out-lever is bigger. Which will jump higher?
Ignore contraction dynamics & imagine the body is constrained to go straight up.
Answer and discuss below 👇 #biomechanics
Postdoc at Structure and Motion Lab, Royal Veterinary College. Biomechanics, animals, robots. Husband and Father of four. Opinions my own. (He/Him) http://dtpolet.com
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