OPEN ACCESS EPRINT: Exploring Explanations of Subglacial Bedform Sizes Using Statistical Models

Thursday, July 28, 2016 at 20:20:08

John K.Hillier, Ioannis A Kougioumtzoglou, Chris R.Stokes, Michael J. Smith, Chris D. Clark, Matteo Spagnolo (in press)

Sediments beneath modern ice sheets exert a key control on their flow, but are largely inaccessible except through geophysics or boreholes. In contrast, palaeo-ice sheet beds are accessible, and typically characterised by numerous bedforms. However, the interaction between bedforms and ice flow is poorly constrained and it is not clear how bedform sizes might reflect ice flow conditions. To better understand this link we present a first exploration of a variety of statistical models to explain the size distribution of some common subglacial bedforms (i.e., drumlins, ribbed moraine, MSGL). By considering a range of models, constructed to reflect key aspects of the physical processes, it is possible to infer that the size distributions are most effectively explained when the dynamics of ice-water-sediment interaction associated with bedform growth is fundamentally random. A ‘stochastic instability’ (SI) model, which integrates random bedform growth and shrinking through time with exponential growth, is preferred and is consistent with other observations of palaeo-bedforms and geophysical surveys of active ice sheets. Furthermore, we give a proof-of-concept demonstration that our statistical approach can bridge the gap between geomorphological observations and physical models, directly linking measurable size-frequency parameters to properties of ice sheet flow (e.g., ice velocity). Moreover, statistically developing existing models as proposed allows quantitative predictions to be made about sizes, making the models testable; a first illustration of this is given for a hypothesised repeat geophysical survey of bedforms under active ice. Thus, we further demonstrate the potential of size-frequency distributions of subglacial bedforms to assist the elucidation of subglacial processes and better constrain ice sheet models.

Lucy Powell: Labour’s Vision for Education

Friday, July 22, 2016 at 10:43:46

An interesting article in Governing Matters (a monthly for UK school governors) this month where they interviewed Lucy Powell, Labour’s shadow education secretary (see her profile at theyworkforyou), to outline current party thinking (and her personal take). In general I would note the tone as progressive but as is typical of opposition parties, it is generally critical (although the rhetoric isn’t strongly this way), with no strong steer on how any measures would be funded - the latter is particularly telling as it relies on successful school leavers contributing more in taxes in the future. Which is just wishful thinking when you are setting budgets!

What caught my attention though was the following question:

What is your vision for the education system in England?

“Like most people’s, it’s one where every child can reach their full potential regardless of background or postcode. And not just their academic potential, they would also develop a rounded character. At the moment, this is all too often the preserve of those you can pay. We’ve got to make sure that today’s education system is equipping our young people for tomorrow’s economy and tomorrow’s society and challenges. There is a lot more we can do to bring together the worlds of work and education.”

This is all very disappointing stuff:

1. “reach their full potential” is almost by definition what education should be, but what does “full potential” actually mean. Be specific - if this is going to become policy, curricula and performance measures then what exactly is that?

2. Not biased by factors beyond a child’s control - I get that, although the previous Lib-Con government had explicitly funded this through the pupil premium.

3. We then return to “potential” - more specifically, “academic” and “a rounded character”. Academic is fair enough - we’ve had 150 years of this and we might argue about what should be in it, but we measure it every year. But what the heck is “rounded character”? Please please please define it for me, tell me how its “taught” and what the metric is for it?!

4. Slightly firmer ground - “equipping our young people”. I say firmer, in that this starts the process of understanding what education is for but - well - says no more about it. What do we need to be equipped to do, what do we need to learn and become proficient in in order to achieve that and how will that be undertaken?

5. It then finishes with “bringing together the worlds of work and education”. At what age, in what way, for what purpose? Is this a sop to apprenticeships or something deeper? Or is this a cynical ploy for a government to develop tax revenue in the future?

Overall I’m left thoroughly underwhelmed if this is the best a pre-scripted shadow education secretary can do. I blogged a while back about “What is education for?” and the topics raised are good starting points for any discussion about the future of education - and particularly the ideas of autonomy outlined by John White. This reminded me of a recent conversation with my 16 year old daughter who bemoaned the fact that she didn’t know how to make an egg mayonnaise sandwich or understand how credit cards work (and commented: “Why don’t they teach this at school?”). These are vital life skills for autonomy. Which brings us back to “reach their full potential regardless of background or postcode” - what is important for children to attain and so what do we want our schools to do? I may not agree with a vision as promoted by Labour or Conservative, but if we start from something explicit we at least have something to work from.

How big is your image? O, 53 billion pixels!

Thursday, July 21, 2016 at 15:57:38

DPReview have a review of Bentley’s rather impressive 53 billion pixel of one of their cars on the Golden Gate Bridge. It might not be obvious at first glance but it is there!! Made up of over 700 photos taken at varying focal lengths (between 300 and 1500mm… bet that puppy cost a few pennies!) using a motorised panoramic tripod head it is one monster of an image that require a fare bit of TLC is post production - most notably the bridge can move ~8m in either direction in high winds! Head on over to Bentley to take a peek.


Wednesday, July 13, 2016 at 09:22:32

DPReview report on a new DJI/Hasselblad tie up that sees Hasselblad bundle their A5D (see my earlier post) medium format camera with DJI’s industrial Matrice 600 drone. The drone has a flight time of ~20mins with the 6kg payload, whilst the A5D ranges up to 60 MP and weighs 1.3kg (body only). This is clearly targeted at the professional aerial imaging sector so expect to see more tie ups on this front.

I’ve not blogged on it yet, but Hasselblad have also recently announced their new X1D, the first mirrorless medium format camera which has a 50MP (43.8x32.9mm) sensor but only weighs 725g (body). Expect to these this making its way into drones pretty shortly! Well… if you have the £7,188 asking price to hand.

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