Photo by sloth x bear on Unsplash

I love my iPad. It’s not exactly new: it’s a 12.9 inch model from three years ago. But even so, it’s light and convenient and fast enough not to be painful.

What I like about it:

  • easy to write with (I have this keyboard)
  • drawing with a pencil is almost as immediate, with almost the same control, as pen and paper
  • it’s easy on the eyes when it comes to reading
  • the split-screen mode is great for taking notes while reading
  • the games are great – I’m fond of iPad re-imaginings of things like Baldur’s Gate
  • when I’m traveling, I…


I’ve just realised why my estimates of R do not tally with the established figures, especially after the peak. The reason is an absurdly simple case of user error, for which I can only apologise.

The R0 estimate.R function accepts an epidemic curve as its primary data. An epidemic curve is a time series of new cases over time. Unfortunately, I have been using the number of confirmed cases over time. This value only increases, so the value of R it calculates will never fall below 1 (although it may reach 1). …


History shows that fewer hours worked does not mean lower productivity

Photo by Luis Cortes on Unsplash

In 2019 Microsoft Japan reported that cutting the working week to four days improved productivity by 40%:

The gains came partly from cost reductions. Less electricity was used and fewer documents were printed.

The shorter week also demanded other, newer efficiencies. For example, meetings were reduced in length and the maximum number of participants was capped.

I’ve noticed something similar in video conference calls. I find physical meetings often expand to fill the time allotted to them, and beyond, not just because of the agenda but simple chit chat at the end or beginning. This doesn’t seem to occur with…


A few weeks ago I announced that I was determined to reach a healthy BMI this year. How am I doing?

The Plan

It’s been a few weeks now since I decided that now was the time to get fit:

The gist of my scheme was as follows:

  • frequent short (10 minute or less) workouts in between homeschooling lessons
  • daily longer duration workouts (eg an hour’s cycling)
  • no alcohol during the week
  • weekly reviews

Tools

I used the following tools to help me track my progress:

  1. My Apple Watch – this is a Series 3 with a Move Goal set to 700 calories. I set the watch face to show the three rings and I make sure I complete all of them. This device…


Herd immunity occurs when enough of the population, by one means or another, are immune to a disease, such that chains of infection are unlikely to occur. Acquiring that immunity can be via a vaccine, or through immunity acquired by an earlier infection.

We can define herd immunity in terms of R, the reproduction number, which is the number of people an individual infects in a population. This comes in two flavours:

  • R0 — this is reproduction number when all members of the population are susceptible — “zero” immunity.
  • Re — the effective reproduction number — this is the value…


So far during the lockdown, I haven’t left the village to any great extent. Occasionally I’d cycle as far as the next village, and sometimes drive to the automatic milk vending machine a few miles away. But I never went on any major roads let alone into the city.

But yesterday I received an email inviting me to have a COVID-19 test as part of my participation in the ZOE reporting program. I don’t know on what basis I’ve been included. …


I have written previously about the R0 package and how it can be used to estimate R, and I have used this to build a Shiny app to re-calculate R on demand with the latest data. In the app, I make a rather wildly inaccurate, or rather, unstable prediction about when the peak or plateau will end by using the slope of R. This instability magnifies the underlying uncertainty in estimated R over time, which in turn depends on the accuracy of the data and the R0 model.

What is the consensus value for R across the UK as I…


My mother and father lived through WW2 – my mother as an Irish immigrant girl evacuated away from her family in London to the countryside in Britain, and my father served in the British Army Intelligence Corps in Dunkirk, North Africa, Italy among other places.

My mother remembers the first celebrations, but she doesn’t speak of it or the war very often. She talks often of the period just after the war, when she met her first husband (a German POW working in rural England) and her travels around a reconstructed Germany. …


COVID-19 data for the UK has been provided in an up to date and tidy form by Tom White and others. I’ve used this source to see how easy it is to plot this data on a map.

Plotting

This data set makes it very easy to plot case, test and death counts. We can grab it and put it into a data frame like so:

caseData <- read.csv("https://raw.githubusercontent.com/tomwhite/covid-19-uk-data/master/data/covid-19-cases-uk.csv") %>%
mutate(Date = as.Date(Date)) %>%
mutate(TotalCases = as.integer(TotalCases))

It looks like this:

Each row is a case measurement for a given area on a particular date. The AreaCode refers to an administrative…


Katsushika Hokusai / Public domain

In Ireland flu vaccinations are being extended so that regular flu doesn’t coincide too badly with the second wave of COVID-19:

I’ve been aware that a second wave was not only possible but likely. I’ve not been giving it much thought. I’ve just been trying to keep up with what’s going on right now. Then I read this:

This article is fascinating in its own right: how a proactive local authority was able to take on COVID-19 rather better than the Netherlands as a whole. But what struck me was this:

His focus now is preparing for the winter, the…

Nick Cotter

Agilist, DevOptician, erstwhile physicist and dabbler in data science

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