Let there be light: Florence Nightingale

This year, 2020, the word Nightingale has acquired new connotations. It is no longer just a word to refer to a passerine bird with beautiful and powerful birdsong, it is the name that NHS England has given to the temporary hospitals set up for the COVID-19 pandemic. In normal circumstances it is indeed a very good name to use for a hospital, but given the circumstances, it becomes more poignant. It is even more so considering the fact that this year, 2020, is the bicentenary go Florence Nightingale’s birth.

Florence Nightingale was born on 12th May, 1820 in Florence, Italy (hence the name!) and became a social reformer, statistician, and the founder of modern nursing. She became the first woman to be elected to be a Fellow of the Royal Society in 1874.

With the power of data, Nightingale was able to save lives and change policy. Her analysis of data from the Crimean War was compelling and persuasive in its simplicity. It allowed her and her team to pay attention to time – tracking admissions to hospital and crucially deaths – on a month by month basis. We must remember that the power of statistical tests as we know today were not established tools and the work horse of statistics, regression, was decades in the future. The data analysis presented in columns and rows as supported by powerful graphics that many of us admire today.

In 2014 had an opportunity to admire her Nightingale Roses, or to use its formal name polar area charts, in the exhibition Science is Beautiful at the British Library.

Florence Nightingale’s “rose diagram”, showing the Causes of Mortality in the Army in the East, 1858. Photograph: /British Library

These and other charts were used in the report that she later published in 1858 under the title “Notes in Matters Affecting the Health, Efficiency, and Hospital Administration of the British Army”. The report included charts of deaths by barometric pressure and temperature, showing that deaths were higher in hotter months compared to cooler ones. In polar charts shown above Nightingale presents the decrease in death rates that have been achieved. Let’s read it from her own hand; here is the note the accompanying the chart above:

The areas of the blue, red & black wedges are each measured from the centre as the common vortex.

The blue wedges measured from the centre of the circle represent area for area the deaths from Preventible or Mitigable Zymotic diseases, the red wedged measured from the centre the deaths from wounds, & the black wedged measured from the centre the deaths from all other causes.

The black line across the read triangle in Nov. 1854 marks the boundary of the deaths from all other caused during the month.

In October 1854, & April 1855, the black area coincides with the red, in January & February 1855, the blue area coincides with the black.

The entire areas may be compared bu following the blue, the read & the black lines enclosing them.

Nightingale recognised that soldiers were dying from other causes: malnutrition, poor sanitation, and lack of activity. Her aim was to improve the conditions of wounded soldiers and improve their chances of survival. This was evidence that later helped put focus on the importance of patient welfare.

Once the war was over, Florence Nightingale returned home but her quest did not finish there. She continued her work to improve conditions in hospitals. She became a star in her own time and with time the legend of “The Lady with Lamp” solidified in the national and international consciousness. You may have heard of there in the 1857 poem by Henry Wadsworth Longfellow called “Santa Filomena”:

Lo! in that house of misery
A lady with a lamp I see
Pass through the glimmering gloom,
And flit from room to room

Today, Nightigale’s lamp continues bringing hope to her patients. Not just for those working and being treated in the NHS Nightingale hospitals, but also to to all of us through the metaphorical light of rational optimism. Let there be light.

Science Communication – Technical Writing and Presentation Advice

The two videos below were made a few years ago to support a Science Communication and Group Project module at the School of Physics Astronomy and Mathematics at the University of Hertfordshire. The work was supported by the Institute of Physics and the HE STEM programme. I also got support from the Institute of Mathematics and its Applications. The tools are probably a bit dated now, but I hope the principles still help some students trying to get their work seen.

The students were encouraged to share and communicate the results of their projects via a video and they were supported by tutorials on how to do screencasts.

Students were also encouraged to prepare technical documentation and the videos for using LaTeX and structuring their documents with LaTeXwere very useful.

Technical Writing

This presentation addresses some issues we should take into account when writing for technical purposes.

Presentation Advice

In this tutorial we will address some of points that can help you make a better presentation either for a live talk or for recording.

Screencasting with Macs and PCs

The videos below were made a few years ago to support a Science Communication and Group Project module at the School of Physics Astronomy and Mathematics at the University of Hertfordshire. The work was supported by the Institute of Physics and the HE STEM programme. I also got support from the Institute of Mathematics and its Applications. The tools are probably a bit dated now, but I hope the principles still help some students trying to get their work seen.

Students were asked to prepare a short video to present the results of their project and share it with the world. To support them, the videos below were prepared.

Students were also encouraged to prepare technical documentation and the videos for using LaTeX and structuring their documents with LaTeX were very useful.

Screencasting with a Mac

In this video we will see some tools to capture video from your screen using a Mac. The tools are Quicktime Player, MPEG Streamclip and iMovie.

Screencasting with a PC

In this video we will see some tools to capture video from your screen using a PC. The tools are CamStudio and Freemake Video Converter.

Uploading a Video to Vimeo

In this tutorial we will see how to set up an account in Vimeo and how to upload your screencast. Also you will be able to send a link to your video to you friends and other people.

Structured Documents in LaTeX

This is a video I made a few years ago to encourage my students to use better tools to write dissertations, thesis and reports that include the use of mathematics. The principles stand, although the tools may have moved on since then. I am reposting them as requested by a colleague of mine, Dr Catarina Carvalho, who I hope will still find this useful.

In this video we continue explaining how to use LaTeX. Here we will see how to use a master document in order to build a thesis or dissertation.
We assume that you have already had a look at the tutorial entitled: LaTeX for writing mathematics – An introduction

Structured Documents in LaTeX

LaTeX for writing mathematics – An introduction

This is a video I made a few years ago to encourage my students to use better tools to write dissertations, thesis and reports that include the use of mathematics. The principles stand, although the tools may have moved on since then. I am reposting them as requested by a colleague of mine, Dr Catarina Carvalho, who I hope will still find this useful.

In this video we explore the LaTeX document preparation system. We start with a explaining an example document. We have made use of TeXmaker as an editor given its flexibility and the fact that it is available for different platforms.

LaTeX for writing mathematics – An introduction

Natural Language Processing – Talk

Last October I had the great opportunity to come and give a talk at the Facultad de Ciencias Políticas, UAEM, México. The main audience were students of the qualitative analysis methods course, but there were people also from informatics and systems engineering.

It was an opportunity to showcase some of the advances that natural language processing offers to social scientists interested in analysing discourse, from politics through to social interactions.

The talk covered a introduction and brief history of the field. We went through the different stages of the analysis, from reading the data, obtaining tokens and labelling their part of speech (POS) and then looking at syntactic and semantic analysis.

We finished the session with a couple of demos. One looking at speeches of Clinton and Trump during their presidential campaigns; the other one was a simple analysis of a novel in Spanish.

Thanks for the invite.

Nobel Prize in Physics 2016: Exotic States of Matter

Yesterday the 2016 Nobel Prize in Physics was announced. I immediately got a few tweets asking for more information about what these “exotic” states of matter were and explain more about them… Well in short the prize was awarded for the  theoretical discoveries that help scientists understand unusual properties of materials, such as superconductivity and superfluidity, that arise at low temperatures.

Physics Nobel 2016

The prize was awarded jointly to David J. Thouless of the University of Washington in Seattle, F. Duncan M. Haldane of Princeton University in New Jersey, and J. Michael Kosterlitz of Brown University in Rhode Island. The citation from the Swedish Academy reads: “for theoretical discoveries of topological phase transitions and topological phases of matter.”

“Topo…what?” – I hear you cry… well let us start at the beginning…

Thouless, Haldane and Kosterliz work in a field of physics known as Condensed Matter Physics and it is interested in the physical properties of “condensed” materials such as solids and liquids. You may not know it, but results from research in condensed matter physics have made it possible for you to save a lot of data in your computer’s hard drive: the discovery of giant magnetoresistance has made it possible.

The discoveries that the Nobel Committee are highlighting with the prize provide a better understanding of phases of matter such as superconductors, superfluids and thin magnetic films. The discoveries are now guiding the quest for next generation materials for electronics, quantum computing and more. They have developed mathematical models to describe the topological properties of materials in relation to other phenomena such as superconductivity, superfluidity and other peculiar magnetic properties.

Once again that word: “topology”…

So, we know that all matter is formed by atoms. Nonetheless matter can have different properties and appear in different forms, such as solid, liquid, superfluid, magnet, etc. These various forms of matter are often called states of matter or phases. According to condensed matter physics , the different properties of materials originate from the different ways in which the atoms are organised in the materials. Those different organizations of the atoms (or other particles) are formally called the orders in the materials. Topological order is a type of order in zero-temperature phase of matter (also known as quantum matter). In general, topology is the study of geometrical properties and spatial relations unaffected by the continuous change of shape or size of figures. In our case, we are talking about properties of matter that remain unchanged when the object is flattened or expanded.

Although, research originally focused on topological properties in 1-D and 2-D materials, researchers have discovered them in 3-D materials as well. These results are particularly important as they enable us to understanding “exotic” phenomena such as superconductivity, the property of matter that lets electrons travel through materials with zero resistance, and superfluidity, which lets fluids flow with zero loss of kinetic energy. Currently one of the most researched topics in the area is the study of topological insulators, superconductors and metals.

Here is a report from Physics Today about the Nobel Prize announcement:

Thouless, Haldane, and Kosterlitz share 2016 Nobel Prize in Physics

David Thouless, Duncan Haldane, and Michael Kosterlitz are to be awarded the 2016 Nobel Prize in Physics for their work on topological phases and phase transitions, the Royal Swedish Academy of Sciences announced on Tuesday. Thouless, of the University of Washington in Seattle, will receive half the 8 million Swedish krona (roughly $925 000) prize; Haldane, of Princeton University, and Kosterlitz, of Brown University, will split the other half.

This year’s laureates used the mathematical branch of topology to make revolutionary contributions to their field of condensed-matter physics. In 1972 Thouless and Kosterlitz identified a phase transition that opened up two-dimensional systems as a playground for observing superconductivity, superfluidity, and other exotic phenomena. A decade later Haldane showed that topology is important in considering the properties of 1D chains of magnetic atoms. Then in the 1980s Thouless and Haldane demonstrated that the unusual behavior exhibited in the quantum Hall effect can emerge without a magnetic field.

From early on it was clear that the laureates’ work would have important implications for condensed-matter theory. Today experimenters are studying 2D superconductors and topological insulators, which are insulating in the bulk yet channel spin-polarized currents on their surfaces without resistance (see Physics Today, January 2010, page 33). The research could lead to improved electronics, robust qubits for quantum computers, and even an improved understanding of the standard model of particle physics.

Vortices and the KT transition

When Thouless and Kosterlitz first collaborated in the early 1970s, the conventional wisdom was that thermal fluctuations in 2D materials precluded the emergence of ordered phases such as superconductivity. The researchers, then at the University of Birmingham in England, dismantled that argument by investigating the interactions within a 2D lattice.

Thouless and Kosterlitz considered an idealized array of spins that is cooled to nearly absolute zero. At first the system lacks enough thermal energy to create defects, which in the model take the form of localized swirling vortices. Raising the temperature spurs the development of tightly bound pairs of oppositely rotating vortices. The coherence of the entire system depends logarithmically on the separation between vortices. As the temperature rises further, more vortex pairs pop up, and the separation between partners grows.

The two scientists’ major insight came when they realized they could model the clockwise and counterclockwise vortices as positive and negative electric charges. The more pairs that form, the more interactions are disturbed by narrowly spaced vortices sitting between widely spaced ones. “Eventually, the whole thing will fly apart and you’ll get spontaneous ‘ionization,’ ” Thouless told Physics Today in 2006.

That analog to ionization, in which the coherence suddenly falls off in an exponential rather than logarithmic dependence with distance, is known as the Kosterlitz–Thouless (KT) transition. (The late Russian physicist Vadim Berezinskii made a similar observation in 1970, which led some researchers to add a “B” to the transition name, but the Nobel committee notes that Berezinskii did not theorize the existence of the transition at finite temperature.)

Unlike some other phase transitions, such as the onset of ferromagnetism, no symmetry is broken. The sudden shift between order and disorder also demonstrates that superconductivity could indeed subsist in the 2D realm at temperatures below that of the KT transition. Experimenters observed the KT transition in superfluid helium-4 in 1978 and in superconducting thin films in 1981. More recently, the transition was reproduced in a flattened cloud of ultracold rubidium atoms (see Physics Today, August 2006, page 17).

A topological answer for the quantum Hall effect

Thouless then turned his attention to the quantum foundations of conductors and insulators. In 1980 German physicist Klaus von Klitzing had applied a strong magnetic field to a thin conducting film sandwiched between semiconductors. The electrons traveling within the film separated into well-organized opposing lanes of traffic along the edges (see Physics Today, June 1981, page 17). Von Klitzing had discovered the quantum Hall effect, for which he would earn the Nobel five years later.

Crucially, von Klitzing found that adjusting the strength of the magnetic field changed the conductance of his thin film only in fixed steps; the conductance was always an integer multiple of a fixed value, e2/h. That discovery proved the key for Thouless to relate the quantum Hall effect to topology, which is also based on integer steps—objects are often distinguished from each other topologically by the number of holes or nodes they possess, which is always an integer. In 1983 Thouless proposed that the electrons in von Klitzing’s experiment had formed a topological quantum fluid; the electrons’ collective behavior in that fluid, as measured by conductance, must vary in steps.

Not only did Thouless’s work explain the integer nature of the quantum Hall effect, but it also pointed the way to reproducing the phenomenon’s exotic behavior under less extreme conditions. In 1988 Haldane proposed a means for electrons to form a topological quantum fluid in the absence of a magnetic field. Twenty-five years later, researchers reported such behavior in chromium-doped (Bi,Sb)2Te3, the first observation of what is known as the quantum anomalous Hall effect.

Exploring topological materials

Around 2005, physicists began exploring the possibility of realizing topological insulators, a large family of new topological phases of matter that would exhibit the best of multiple worlds: They would robustly conduct electricity on their edges or surfaces without a magnetic field and as a bonus would divide electron traffic into lanes determined by spin. Since then experimenters have identified topological insulators in two and three dimensions, which may lead to improved electronics. Other physicists have created topological insulators that conduct sound or light, rather than electrons, on their surfaces (see Physics Today, May 2014, page 68).

Haldane’s work in the 1980s on the fractional quantum Hall effect was among the theoretical building blocks for proposals to use topologically protected excitations to build a fault-tolerant quantum computer (see Physics Today, October 2005, page 21). And his 1982 paper on magnetic chains serves as the foundation for efforts to create topologically protected excitations that behave like Majorana fermions, which are their own antiparticle. The work could lead to robust qubits for preserving the coherence of quantum information and perhaps provide particle physicists with clues as to the properties of fundamental Majorana fermions, which may or may not exist in nature.

—Andrew Grant