Archive for August, 2020

Bird 100: Ah Leu Cha

Posted in Jazz with tags , , , on August 29, 2020 by telescoper

Second post today to mark the centenary of the great alto saxophonist Charlie Parker (“Bird”), undoubtedly one of the most influential musicians of the twentieth century. Together with trumpeter Dizzy Gillespie, Bird effectively created a revolution in Jazz after the end of World War II in the form of a new style called bebop.

Sadly, as with many Jazz legends, Charlie Parker died young as a result of chronic alcoholism and, especially in his case, drug addiction. He became hooked on heroin when he was a teenager and when he couldn’t get heroin he used anything else he could. The result was a body ravaged by abuse and a career frequently interrupted by illness. When he died, at the age of 35, the doctor who signed his death certificate estimated his age as “about 60”.

I remember, as a teenager, finding a Charlie Parker LP in a second-hand record shop and buying it for 50p. When I got home I put it straight on the record player and couldn’t believe my ears when I heard the staggering virtuosity of his playing. I just didn’t realise the alto sax could be played the way he played it. I’ve been a devout Charlie Parker fan ever since, although most of recorded output is quite difficult to get your hands on. In fact, the first record I bought as an LP has never been released on CD, which I think is a scandal.

Many people I know can’t really stand any Jazz that’s stylistically dated after about 1940. I have never really understood this attitude. To my mind the two tracks I’ve picked here, recorded in 1948, sound as fresh and exciting to me now as they did when I first heard them 30 years ago. They also seem to me firmly rooted in a wonderful tradition of music-making that reaches back to Louis Armstrong and King Oliver and forward to the likes of John Coltrane, Eric Dolphy and Ornette Coleman. Anyway, I’m not going to preach. I love this music and it’s up to you whether you agree or not.

Parker’s ideas didn’t just remain within jazz, and bebop had a huge cultural influence on post-war America. It never became as popular as pre-war Jazz, but had a devoted following on both sides of the Atlantic and breathed new creative life into a form that was in danger of becoming stale and commercialized.

The piece is called Ah Leu Cha and – as far as I’m aware – it is the only tune Bird ever wrote that involves any kind of counterpoint (provided by a very young Miles Davis on trumpet).

Bird 100: Anthropology

Posted in Jazz with tags , , , , , , on August 29, 2020 by telescoper

Today marks the 100th anniversary of the birth of the great Charlie Parker, who was known to his friends as “Bird”. I’ve posted more than a few examples of Charlie Parker’s music over the years so I thought I’d celebrate the centenary with a bit of a flood.

I thought I’d start with this clip (inevitably without video I’m afraid) is in fact taken from the first ever Charlie Parker LP I bought when I was about 15 and which I still have. I bought it on impulse, not really knowing who Charlie Parker was, was this record that turned me onto his music and I’ve never turned off.

No information is provided on Youtube, but referring to the sleeve note reveals that the track was recorded from a radio broadcast live from Birdland in New York City on March 31st 1951 using a primitive disc recording machine by an amateur recording buff called Boris Rose. The sound quality isn’t great, but he deserves much greater recognition for capturing this and so many other classic performances and preserving them for posterity.

The personnels consist of Charlie Parker (alto saxophone), Dizzy Gillespie (trumpet), Bud Powell (piano), Tommy Potter (bass) and Roy Haynes (drums).

Here’s what the sleevenote (written by Gary Giddens) says about this track:

“Anthropology is an “I Got Rhythm” variation which originally appeared, in a slightly different form, as “Thriving on a Riff” on Parker’s first session as leader. The tempo is insanely fast; the performance is stunning. Bird has plenty of ideas in his first chorus, but he builds the second and third around a succession of quotations: “Tenderly”, “High Society”, “Temptation.” Gillespie’s second chorus is especially fine – only Fats Navarro had comparable control among the trumpeters who worked with Bird. His blazing high notes tend to set his lyrical phrases in bold relief. Bud, the ultimate bop pianist (and much more), jumps in for two note-gobbling choruses: no quotes, though, it’s all Powell. The four bar exchanges that follow demonstrate Hayne’s precision.

Spot on, but words aren’t really enough to describe this scintillating music, so listen!

Primordial Figures

Posted in Biographical, The Universe and Stuff with tags , , , , on August 28, 2020 by telescoper

I was rummaging around looking for some things related to a paper I’m struggling to finish before term starts and I found some vintage diagrams. They brought back a lot of memories of working on the textbook I wrote with Francesco Lucchin way back in the 1990s. In particular I remember how long it took to make these figures, when nowadays it would take a few minutes. In fact I’m thinking of setting this as a Computational Physics project for next year. These are not full computations either, just a simple fluid-based approach.

The curves show the evolution of fluctuations in both matter δm and radiation δr on a particular scale (i.e. a Fourier mode of given wavelength) defined as δm=δρmm, etc.  The x-axis shows the cosmic scale factor, which represents the expansion of the Universe and in both cases the universe is flat, i.e. it has a critical density. The first graph shows a universe with only baryonic matter:

Notice the strongly coupled oscillations in matter and radiation until a scale factor of around 10-3, corresponding to a redshift of a thousand or so, which is when matter and radiation decouple. The y-axis is logarithmic so the downward spikes represent zero points.

It is these oscillations which are responsible for the bumps and wiggles in the spectrum of the cosmic microwave background spectrum, as different Fourier modes arrive at the last scattering surface at a different phase of its oscillation. Of course going from the Figure above to the CMB fluctuation spectrum (see below) involves more calculations, and there is now a well-established machinery for doing these with full physical descriptions, but I think the above diagram makes the physical origin of these features clear.

The CMB power spectrum from Planck

The second diagram shows what happens if you add a third component called `X’ in the Figure below which we take to be cold non-baryonic matter. Because  this stuff doesn’t interact directly with radiation (while baryons do) it doesn’t participate in the oscillations but the density perturbations just carry on growing:

Notice too that at late times (i.e. after the baryonic matter and radiation have decoupled) the baryonic component grows much more quickly than in the first Figure. This is because, when released from the effect of the photon background, baryons start to feel the gravitational pull of the dark matter perturbations.

There’s nothing new in this of course – these Figures are thirty years old and similar were produced even earlier than that – but I still think pictures like these are pedagogically useful,

 

Home in Ireland

Posted in Biographical, Maynooth with tags , , , on August 26, 2020 by telescoper

Just after 5pm yesterday I got a phone call from my solicitor telling me that all the formalities relating to my purchase of a house had been completed and the keys had been released. That gave me just enough time to finish what I was doing and head to the Estate Agent before they closed to get the keys. When I got there I found that a card and a bottle of wine were included, which was nice.

So now I own a house in Ireland, a rather lovely bungalow to be precise. It’s rather empty at the moment but I’ll be moving things in gradually over the next few days from my flat which I have until the end of the month. It will still be rather empty after I’ve done that because a lot of my stuff is still in Wales. I’ll have to figure out a plan to get over there and arrange to have it moved here to Ireland, though the timing of  that is rather dependent on Covid-19 restrictions…

I have bought and sold properties in England (and Wales) a few times. The process here in Ireland as many similarities but also some differences. One big difference is the auction process. Estate agents here in Ireland are generally called auctioneers, actually. In order to register to bid you have to first show that you have the necessary funds and then you can place a bid online and then there’s a genuine auction, with bid and counter-bid. It’s easy in an auction to get drawn in so far that you end up spending more than you wanted to, so I decided on an absolutely upper limit on how high I would go. Fortunately on the house I ended up buying the bidding stopped well below that.

There are a few other differences. One is that stamp duty is just 1% in Ireland (for properties up to €1M) whereas in England it is much more complicated but for a property  in England of similar value to mine it would be 5%. Incidentally there is also a Local Property Tax (LPT) based on the value of your home – similar to the old system of rates in the UK. The amount payable however is much lower, which is why local councils have so little money in Ireland and many services are privately run. You have to pay a private refuse and recycling company to deal with your garbage, for example. Which reminds me that I have to organize that.

I have to say I found the business of getting a mortgage a bit painful. Banks in Ireland are still saddled with bad mortgage debt from the time of the Credit Crunch about a decade ago so they are extremely cautious. I had to supply a huge amount of paperwork – about my income, savings, previous residences, etc  – before the bank agreed to lend me money. Then the Covid-19 lockdown intervened and by the time we got moving again, in June, I had to supply all that information again because the documents were then out of date.

You also have to take out mortgage protection insurance, a form of life insurance policy. For that I had to have a full medical examination – the second such I’ve had in three years. (The previous one was when I joined the staff here at Maynooth). There’s also buildings insurance. If I have one word of advice for anyone thinking of buying a house in Ireland it is to do with the insurance policies. Banks and other lenders tend to be tied agents of certain insurance companies so if you ask your mortgage lender to arrange the insurance they will go with one company. When I did that I found the policies were at least 50% more expensive than the market rate. Fortunately I was able to get some local advice and got mine sorted independently at a very much more reasonable cost than those offered by the bank itself.

Other than that the business of mortgages and valuations and surveys and Land Registry is all tediously familiar.

One of the good things about having lived in Maynooth for a while before buying a house is that I know people who can give local recommendations. The solicitor who did the conveyancing was very efficient and competent, though it was very strange doing everything by Zoom, including witnessing the signing of documents!

Once I’d had my offer accepted, the process of actually taking possession of the house took about two months. I’m told that is exceptionally fast as these things go in Ireland, but the vendor and I both wanted to move quickly – I really wanted to get everything sorted before the start of term – and we were both prepared to nag the various people involved to make it happen.

Now all I have to is to arrange with the various utilities companies to have accounts switched to my name, notify various changes of address, buy some bits and bobs, and finish the moving of my gear. Lots to do, but it’s a nice feeling to have my own place once again.

P.S. I bought a piano from the vendor, but it badly needs tuning!

 

 

 

Back to School

Posted in Biographical, Covid-19, Education, Maynooth with tags , , , , on August 26, 2020 by telescoper

News that primary and secondary schools in Ireland are re-opening this week reminded me of this picture I saw a year ago:

I suppose the items on display there provide one way of dealing with the stress of worrying whether re-opening will result in a large increase in Covid-19 cases!

Meanwhile the Third Level sector is also preparing to re-open. Although we have another month to go before teaching is supposed to restart at Maynooth University, I’m already getting quite a few emails from students asking what things are going to be like when it resumes in September. All I can answer is what our plans are, but whether or not we can put those plans into practice depends crucially on things outside my control, including local factors (such as the number of students taking each module) and national factors (especially the restrictions intended to prevent the spread of Covid-19).

On the first matter we’ll have to wait until students register which, for first years will be very late in the day because of the delayed leaving certificate results this year. We will know a bit sooner about returning students, but even for them it will be a couple of weeks or so.

The national picture is even more uncertain. As of yesterday, the average number of new Covid-19 cases per day over the last 7 days was an uncomfortably high 103.6:

Over the next month will the local lockdown in Kildare carry on? What will be the impact of schools’ reopening? Will the national Covid-19 picture improve or deteriorate? Although at this stage we plan to resume (partly) campus-based teaching on September 28th, but we have to accept that if things take a turn for the worse we might not be able to do that and will instead have to go online. We’ll just have to wait and see.

That doesn’t help students, of course, because they have to make decisions about accommodation and travel. It’s a very awkward and stressful situation for them but I think the only way to approach the queries I’m getting is to tell the truth. Sometimes “I don’t know” is the only honest answer.

At least my own preparations are proceeding. I’ve just had my own tensor barrier put in. This is intended to deter people from wandering into my office and spreading their germs. I don’t think the installation is finished yet, however, as it doesn’t seem to be connected to the mains electricity.

The Storm in Ireland

Posted in Covid-19, Politics with tags , , , on August 25, 2020 by telescoper

I’m sitting in my office eating a sandwich and listening to the rain. Last night Storm Francis arrived – the picture above was what I saw on the weather app on my phone just before I went to bed, with the storm approaching from the I was very tired so went straight to sleep and fortunately wasn’t woken up by the storm. It probably wasn’t as windy as Storm Ellen but there’s been a heck of a lot of rain, and it’s still coming down.

Storm Francis isn’t the biggest storm going on in Ireland at the moment, though. Last week a quite different tempest brewed up, a political one, the consequences of which have already been quite severe for certain members of the Government. There’s now even a Wikipedia page about the Oireachtas Golf Society Scandal, known colloquially as Golfgate, which means I don’t have to explain too much about it. The story in a nutshell that 81 people, including a number of prominent politicians, attended a golf club dinner that violated Covid-19 restrictions. It has already caused two politicians to resign from their main offices, and a host of apologies have been made, but I don’t think it’s over yet. People are justifiably furious about politicians and other public figures behaving as if they are above the law while others are enduring lockdown conditions. There are definite shades of Dominic Cummings and his trip to Barnard Castle.

One outstanding issue is the conduct of EU Trade Commissioner, Phil Hogan, who not only attended the dinner but also travelled to Kildare (which is under special restrictions) on the way there and, it subsequently emerged, was stopped by Gardaí for talking on his mobile phone will driving. He has been asked to account for his actions by his boss, Ursula von der Leyen, to whom he has handed over a `20-page dossier’ explaining his movements. One wonders what else is in that document that we don’t yet know about.

Update: 26th August. Phil Hogan resigned.

In my opinion, Hogan should be sacked if he won’t resign but there is an issue about how to prevent this sort of thing happening in future. The answer to me is obvious: an interest in golf is clearly an indication of poor judgement so anyone who plays golf, or is interested in golf in any way, should be barred from holding any form of public office.

I rest my case.

New Publication at the Open Journal of Astrophysics!

Posted in Maynooth, Open Access, The Universe and Stuff with tags , , , , , , on August 24, 2020 by telescoper

So another new paper has been published in the Open Journal of Astrophysics! This one is in the folder marked Astrophysics of Galaxies and is entitled Massive Star Formation in Metal-Enriched Haloes at High Redshift. I should explain that “Metal” here is the astrophysicist’s definition which basically means anything heavier than hydrogen or helium: chemists may look away now.

The authors of this paper are John Regan (of the Department of Theoretical Physics at Maynooth University), Zoltán Haiman (Columbia), John Wise (Georgia Tech), Brian O’Shea (Michigan State) and Michael Norman (UCSD). And before anyone asks, no I don’t force members of staff in my Department to submit papers to the Open Journal of Astrophysics and yes I did stand aside from the Editorial process because of the institutional conflict.

Here is a screen grab of the overlay:

You can click on the image to make it larger should you wish to do so.

You can find the arXiv version of the paper here.

Eddington in Cardiff 100 years ago today: the first proposal that stars are powered by fusion

Posted in Cardiff, History, The Universe and Stuff with tags , , on August 24, 2020 by telescoper

Here’s a fascinating bit of astrophysics history by former Cardiff colleague Bernard Schutz: one hundred years ago today, Arthur Stanley Eddington gave a talk in Cardiff in which he, with great prescience, proposed the idea that stars might be powered by nuclear fusion.

The Rumbling Universe

One hundred years ago today, on 24 August 1920, with over 1000 people gathered in Cardiff for the annual meeting of the British Association, Arthur Eddington gave his address as the incoming president of the physical and mathematical sciences section. He elected to speak on the subject of the “Internal Constitution of the Stars”. When I first came across the text of the address last year (published in Nature in 1920), I was amazed to find as early as this such an insightful proposal that stars are powered by the synthesis of helium from hydrogen. But what really brought me up short was this sentence:

If, indeed, the sub-atomic energy in the stars is being freely used to maintain their great furnaces, it seems to bring a little nearer to fulfilment our dream of controlling this latent power for the well-being of the human race – or for…

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The Week Ahead

Posted in Biographical, Covid-19, Education, Maynooth with tags , on August 23, 2020 by telescoper

On Friday I finished correcting the batch of Repeat examinations that were within my remit. I think the other staff have done likewise. All the marks now get uploaded and cross-checked and before another meeting of the Exam Board the year’s examination process to an end.

There’s no time to pause, however, as we go straight into the preparations for next academic year. Nobody knows quite how things are going to go, and no doubt we’ll have to adapt quickly to changes in the national situation. County Kildare, wherein Maynooth is located, remains in a sort of mini-lockdown for the next two weeks. It is not a very welcome distinction to be in the only County under “special measures” – Laois and Offaly – were stood down on Friday – but I’m optimistic that local Covid-19 outbreaks will be sufficiently well controlled to let us relax fully well before term starts.

At least after the Repeats we will know how many returning students we have on which modules so can start firming up the arrangements for Years 2 to 4.

Year 1 will have to wait for the Leaving Certificate results which won’t be out until after September 7th. Teaching starts on 28th September so final arrangements for new students will have to be made at the last minute. As it happens I’m teaching the first module for Mathematical Physics. I have a basic a plan of what I want to do but the details are dependent on precisely how many students we have.

For new students there is an Orientation Week before teaching starts which this year will be virtual, so in preparation for that I’ll be recording video presentations for the new students on different courses. They all have to be done by Wednesday.

There’s also sorting out contracts for tutors, training on new software and hardware for teaching, and writing lecture notes to be getting on with.

On top of all that, if there are no last minute hitches, I should be getting the keys to my new home on Wednesday so will be moving in later in the week. I have paid this month’s rent on the flat so have until the end of the month to move out. I can therefore do a relatively gradual transition over a few days, working around work commitments. Not that I have much to move: a lot of my personal effects are still in Wales and there’s no way I can get back retrieve them at the moment. Although the timing could have been better, I’m looking forward to living in a home of my own once more.

Two X One Y

Posted in Film, The Universe and Stuff with tags , , on August 22, 2020 by telescoper

I found out yesterday that the title of the above paper (on arXiv here) has been causing a bit of a scandal in the astrophysics community.

When I saw the title I was baffled as to why it could cause offence. Then I was told that it was a reference to pornography. I still didn’t understand at all. Then I was told the title of the film to which it is alleged to refer: Two Girls One Cup. I had never heard of it until yesterday and wish I hadn’t because it’s so gross. It is so notorious that it even has a Wikipedia page describing it and reactions to it. Don’t click if you’re easily disgusted. I am fairly broad-minded but I found it entirely disgusting.

I’m told that the film generated a large number of derogatory and misogynistic memes circulated on social media but they all passed me by too. I must be too old.

But even knowing about the film I still don’t see the paper’s title as a reference to it. Had it been an attempt to be a pun then I would have got it, but I don’t think it is. “Flares” and “shock” don’t rhyme with or sound anything like “girls” and “cup”. If it was meant as a pun it’s a failure on two counts. Is every phrase of the form “Two X One Y” now a reference to scat porn?

If anything I would interpret the title as a reference to the idiomatic expression “to kill two birds with one stone”. Or it could just be a reference to the fact that the paper is about two flares associated with one shock.

Regardless of my opinions, though, if this combination of words has caused offence – whether intentionally or not – then it is not a big deal to change the title and that’s what should be done. I’d suggest that simply inserting “with” or “from” would do the trick.

The comments I saw on Twitter yesterday basically divide into those like me who didn’t get the alleged reference at all and those who were appalled. The latter were almost exclusively younger people based in America (who are more likely to have been exposed to the film) . The authors of the paper are predominantly based outside the USA and in my view it would be a mistake to assume they all share the same cultural experience as a particular demographic of the United States. I think it would be very unfair to jump to the conclusion that the reference is deliberate.

I’m genuinely interested to see what people think about this title. I realise I have spoilt this by giving the background, but here’s a poll. Please answer by giving your initial reaction.

Update: the title has been changed, as I suggested…