Index of Blogs (2018-2019) and Courses

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Click here for list of Talks and Blogs prior to 2018



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6 January 2021  Colours in the Environment: PART 1: Sky, Clouds, Sunsets, Twilights, NLCs; Some Fascinating 

                                Physics in Play; Interaction of Light with Matter

27 November 2020   Artificial Light at Night is a Rapidly Growing Problem with Serious Health 

                                & Ecological Implications; Solutions are Relatively Simple: 

                                A Public Information Feature

24 October 2020    Colour of Objects: Visible Light Spectrum; Primary Colours; 

                                Optical Illusions; How Do Colours Work?

13 October 2020    Net-Zero by 2050 - How does One Eliminate Emissions from 

                                Agriculture, Heavy Transport & Industry? 

                                _A Community Education Feature

31 August 2020    Climate Change - Present Status & Future Prospects: 

                                Talk at WES (Scotland)

17 August 2020   Biodiversity Loss in the Anthropocene; Impact on Human Welfare

4 August 2020  What is Light? All You Need to Know - A Community Education Feature

16 July 2020    Climate Change - Awaz Radio, Glasgow 15th July 2020
27 May 2020  IMO 1988 Problem 6: General Term Using School-Level Maths

10 February 2020   Big Data, Artificial Intelligence and Freedom - 

                                       Cyber Dystopia and Beyond

24 January 2020   7.75 Billion and 415 ppm; 4C Warmer World is Really Bad News

18 December 2019   Climate Change; Indecision at COP25 in Madrid; 

                                    Fiddling as the Planet Burns

18 December 2019  Making Sense of our Climate Change: 

                                    6. Carbon Isotope Studies Prove That Human are 

                                    Responsible for Global Warming

14 December 2019   Making Sense of our Climate Change:

                                     5. Carbon Cycle and the Keeling Curve

10 December 2019   Making Sense of our Climate Change: 4. Global Warming Indicators

2 December 2019     Isaac Newton_Troubled Genius: 1. Family Tree; Early Years

1 December 2019  Making Sense of our Climate Change: 3. The Science of Global Warming

19 November 2019   Making Sense of Our Changing Climate: 2. Weather and Climate

17 November 2019      Making Sense of Our Changing Climate: 1. Introduction

1 November 2019   Outdoor Air Pollution in Delhi - an Update

3 October 2019    Common Sense and Superstitions - Personal, Cultural, 

                                Spiritual and Scientific Dimensions

11 September 2019       Limits to Sustainable Human Energy Production 
13 July 2019  Pillars and Sinks of Healthy Ageing

26 June 2019 Longevity and Quality of Life - Lifestyle and Chronic Diseases - 

                                It is Time to Reflect on How We Live
5 May 2019  SLEEP (Part 2): Why Do We Need to Sleep? 

                            The Science of Sleep & Circadian Rhythm

12 March 2019  Air Pollution (Part 2) - Particulate Matter PM10 and PM2.5 - 

                                Brake and  Tyre Wear are Higher Emitters than Car Exhausts

21 January 2019  Global Greenhouse-Gas (GHG) Emissions by Humans and Animals 

11 January 2019  SLEEP (Part 1): Why Do We Need to Sleep Eight Hours per Day? 

                                    Malaise caused by Impaired, Insufficient Sleep

27 December 2018  Routines; Habits and Addiction; An Outreach Feature

16 December 2018  Are the Young More Creative/Innovative? - Not Really (Part 2)

09 December 2018  Are the Young More Creative/Innovative? - Not Really -

                                    Another Example of Perils of Perception (Part 1)

28 November 2018  Ethics of Eating Meat - We Need to Factor-in Sustainability

26 November 2018  A Magic Square based Party Game

25 November 2018  Why Do Humans Have two Front-Facing Eyes? 

                                    An Analysis & Some New Ideas

17 November 2018  Air Pollution (Part 1) - The Invisible Killer; 

                                    Particulate Matter PM2.5

27 October 2018  In Praise of BMI: Not Perfect But an Exceedingly Useful and 

                                    Convenient  Parameter for Measuring Obesity

23 October 2018  Over-population is 'Elephant in the Room'; 

                            Why Do We Not Address the Real Problem?

21 October 2018         Recreational Maths with Smartphone Calculator - 

                                 10 Games to Wow Your Friends

16 October 2018        Additive and Multiplicative 3X3 Magic Squares - 

                                 Construction and Some Not So Well Known Properties

6 October 2018       Obesity in Children - Weight at Ages 3 to 6 is Critical in  

                                    Determining Obesity in Later Life

21 September 2018  Perimeter and Area of Regular Polygons - 

                                    From Triangles to Circles -  The Iso-Perimetric Theorem

9 September 2018   The Rise of Tech Companies - Threat to Privacy and Freedom - 

                                        Cyber Dystopia

11 August 2018      A Simple Estimate of Global Mean Sea Level Rise due to

                                        Increase in Global Temperatures

3 August 2018        Myths and Hypes about the Ubiquity of the Amazing Golden Ratio; 

                                 Its Relation to Fibonacci Numbers; Logarithmic Spiral, Phyllotaxis 

                                 and the Pentagram

6 July 2018            Derivation of nth Term of a Lucas Sequence - 
                                 Fibonacci Numbers and the Golden Ratio

7 June 2018           Enhanced Reactivity of Powders, Number of Surface Atoms; 

                             Inter-Atomic and -Molecular Forces

31 May 2018          Sum of Powers of Digits in a Number - 
                                 Iterations lead to a Fixed Point or a Limit Cycle 
25 May 2018             Optimal Car Separation at Traffic Lights - 
                                 Current Driving Habits Require a Rethink
21 May 2018          Surface to Volume Ratio for a Spheroid, 
                                 Cylinder, Cone and Rectangular Box - A Quantitative Analysis
13 May 2018             Climbing a Conical Mountain -- Almost Impossible  
                                Shortest Path, and a Realistic Path You Can Use 
29 April 2018              A Couple of Challenging Geometry puzzles - Created by 
                                 Martin Gardner - Recreational Mathematics 
22 April 2018             What is the Number(s) of the Torn Page/Pages? - 

                                Two Seemingly Impossible Puzzles
18 April 2018         Division of a Huge Cake: An Interesting Mathematical Puzzle
21 February 2018    Undefined/Indeterminate Mathematical Operations 

                                 Involving Zero and Infinity lead to fallacies and paradoxes  
18 February 2018   Physics of Humidity, Relative 
                                Humidity, Health Implications of Low or High Humidity

12 February 2018   Letter Frequency in Spellings of Words and 

                                        Numbers in the English Language 
8 February 2018           Math Puzzles - How logical approach makes 

                                    them much more delicious
30 January 2018          The Awesome Number 2 : Puzzles, Games, 

                                    The Power of Doubling
28 January 2018            Number Puzzles for Mental Arithmetic Enthusiasts

26 January 2018            The Science of Hypothermia, Windchill, Frostbite -  When 

                                         Body's Thermal Regulation Mechanism is Unable to Cope...

23 January 2018       The Science of Heatstrokes (Hyperthermia) -  

                                        When Body's Thermal Regulation Mechanism 

                                        is Unable to Cope...

16 January 2018          Heat given off by a human body is about 100 Watt

15 January 2018          Galileo Galilei - Family Tree, Friends and Foes

Contact email:  ektalks@yahoo.co.uk

Courses  -  Each course is 8 to 12 hours duration.  Courses are suitable for 'inquisitive' laymen with no serious science background. The courses are designed for outreach activity, non-mathematical and have been given in East Kilbride (Scotland) and other venues. 

Please click on a course to start:

Albert Einstein and his Theories of Relativity 

Nuclear Physics    

Climate Change  

Sustainable Development 

Medical Imaging 

Great Scottish Inventors 
James Watt
 Lord Kelvin
 Alexander Fleming
 Alexander Graham Bell
 James Clerk Maxwell

Nano Technology 

Nuclear Weapons - The story of the Atomic Bomb

Age of the Earth & Milky Way

 (Radio-isotope Dating)     

SLEEP (Part 2): Why Do We Need to Sleep? The Science of Sleep & Circadian Rhythm____ A Community Education Feature

Who am I?  Blog Index

When people ask me: “what’s more important, diet or exercise?” 
I typically answer: “sleep.”                                     Dr. Nalini Chilkov

(This part was used for a talk at the Burnbank Centre, Hamilton, Scotland in April 2019)

Sleeping seven to eight hours a day is essential for adults.  In Part 1, I have discussed the evidence from recent scientific research about the relevance of sleep for humans and animals with the clear message that sufficient sleep (7 to 8 hours) is not only important for our physical and mental health/welfare, but a lack of good quality sleep has many serious unwelcome consequences (See slide below for a summary).

  (click on the slide to see full page image; press Esc to return to text)

People who sleep too little or too long have increased chances of dying and occurrence of major cardio-vascular events. It is recommended that adults sleep 8 hours per day but children should sleep somewhat longer depending on their age. 

Along with good diet, clean water, clean air and adequate exercise, sleep is one of the five pillars of good health. 

Electrical Activity of the Brain and Sleep Cycles:  Our brain controls most body functions through electro-chemical signals.  The neurons in the brain are actively talking to each other.  In fact, human brain weighs 1.3 kg (about 2% of the body mass) but is responsible for consuming about a quarter of the base metabolic energy (the brain's energy consumption is ~600 Calories per day). 
Interestingly, the brain uses as much energy when we sleep as it does when we are awake - even more during some periods of sleep.  
When awake, we are interacting with the world around us - thinking and making decisions, and a large amount of input is provided to the brain from objects and events around us. 
When sleeping, the brain is certainly not interacting with the outside world and the question is - what is the brain using the vast amount of energy for? 

Let us first look at the way the electrical activity of the brain is measured and point out the differences & relevance of different types of sleep.

An EEG, electroencephalograph, collects electrical activity from the brain and plots the signal as function of time.  The wavy pattern tells us what is happening in the brain.  One can study signal from individual parts of the brain to learn how active different parts of the brain are at any particular time.

Despite a large amount of descriptive information about the various stages of sleep, the functional purposes of the sleep states are not known. Whereas, most sleep researchers accept the idea that the purpose of non-REM sleep is at least in part restorative, the function of REM sleep remains a matter of considerable controversy.

In the following slides, I shall present typical electrical activity of the whole brain during when you are awake and in different phases of sleep. 

A healthy adult sleeps 7 to 8 hours per day and cycles between different stages of sleep in a consistent manner - generally there are 5 cycles, each lasting 90 minutes. The electrical activity of the brain may be represented on a hypnogram - a record of the stages of sleep as a function of time -  generally plotted in 30 sec intervals.  A typical situation is shown in the slide:

Most slow wave sleep (NREM3) occurs in the first two cycles while REM sleep dominates the last two cycles before waking.

Sleep is also essential for disposing metabolic waste from the brain - this is explained in the next slide

Molecules that Make Us Sleep: There are two ways human body feels sleepy. 
1.  Circadian rhythm causes secretion of hormone melatonin at certain time of the day (at the onset of darkness). Melatonin tells the body that it is time to rest and sleep.  More of this later...
2.  The chemical adenosine acts as a sleep-inducing (hypnogenic) molecule. Adenosine is produced by the break up of adenosine triphosphate (ATP) during  energy generation to power bodily functions.  The activity of the neurons and gilial cells causes a build up of adenosine in the brain and this increases the sleep pressure.  After 12 to 16 hours of wakefulness, the level of adenosine and hence the sleep pressure reaches a high value and one has a strong desire to sleep.  During sleep, adenosine is destroyed and after 8 hours of sleep, adenosine levels reach a low value with a correspondingly weaker sleep pressure.  This is shown in the slide:

Adenosine works by attaching itself to receptor sites in the brain to induce sleep pressure.  Substances like caffeine have similar molecular structure to adenosine and are present in tea, coffee, coke and many other food items.  Caffeine attaches to adenosine receptors in the brain and prevents the build up of sleep pressure.  That is why, it is advisable to avoid caffeine 4 to 5 hours before sleeping time in order to ensure a good night sleep.

Circadian Rhythm (Internal Biological Clock): 
Different body functions rise and fall at set times of the day based on your circadian rhythm. Your circadian rhythm controls when you should sleep and when you should be awake (alert and active).

Additional Recent Information:  Night owls: Simple sleep tweaks boost wellbeing (10 June 2019)

Final Word: Good quality sleep of 7 to 8 hours is absolutely essential for adults - children need more. The benefits are huge ..

The science of sleep is fascinating and, like anything else in the human body, complicated.  I am really curious to learn about the dreams - why do we dream and what is the purpose - as I had said in part 1, evolution does not do anything without a reason - there must be an important function that dreams serve - we just need to find it.  Wait for part 3...

Please pass on the link to friends and family; sleep is an important enough topic to worth shouting about. 

Please click here for PART 1 https://ektalks.blogspot.com/2019/01/sleep-part-1-why-do-we-need-to-sleep.html

Recent references:  https://www.medscape.com/viewarticle/914244_1

Air Pollution (Part 2) - Particulate Matter PM10 and PM2.5 - Brake and Tyre Wear are Higher Emitters than Car Exhausts

Who am I?  Blog Index

In Part 1, I had discussed the nature and adverse health effects of outdoor air pollution that is particularly serious in almost all major cities and is responsible for nearly 5 million deaths annually.  In cities, road transport is a major source of air pollutants - particularly particulate matter - the subject of this publication. 
In Central London,  road transport is responsible for 54% of particulate matter PM10 (all particles less than 10μm diameter) emissions and for 48% of the harmful  oxides of nitrogen.  
The issue of transport in cities is a complex problem - petrol and diesel vehicles are generally blamed for the pollution.  However, under the new low emission legislation, pollution from exhausts has been falling and the main problem in future will be particulate matter generation by brake wear and tyre wear (BWTW), road surface wear and other particulate matter that already exists in the environment and become suspended due to traffic induced turbulence.  Non-exhaust emissions are equally important for electric vehicles (EVs) and it seems that PM emissions will continue to be a serious health hazard in cities until a better way to move people is found. 

Airborne PM2.5  are capable of bypassing human noses and throats, penetrating deep into the lungs where they deposit harmful chemicals adsorbed on their surfaces. Their presence has been linked to a number of health conditions, including respiratory illnesses (for details, see Part 1).

Experts estimate that by 2030, as the transport sector moves into electric vehicles, 90 per cent of harmful PM2.5 emissions will be caused by microscopic particles eroding from tyres &  brakes and particles airborne from road and surrounding surfaces.

The UK government's clean air strategy plans to develop new standards for tyres and brakes to address toxic non-exhaust emissions. Similar planning is underway in most major economies. At the same time, the size of cities is growing rapidly with 75% of the world population expected to live in urban areas by 2050 with a corresponding increase in road traffic and emission of particulate matter.   

New products and technologies are crucial in achieving clean air in our cities - for example, Bosch has recently launched a new iDisc brake disc with a tungsten carbide coating that emits 90% less brake dust than a conventional cast iron disc. Regenerative braking, most effective in stop/start driving typical of the traffic in cities, in hybrid and electric vehicles (EVs) reduces the need for friction braking greatly, thus cutting down on particulate emissions. More on this later.

In this publication, I look at the non-exhaust particulate emission in more detail and discuss what may be done to improve the quality of outdoor air.  Unlike exhaust emitted particles, there are no standard methods for characterising non-exhaust particulate matter and it is sometimes difficult to compare results of different studies. A good estimate of how much particulate matter (in mg per km of travel) is emitted is provide by the following figure

Concentrating on PM2.5 particles, we note that heavier cars generate greater quantity of particulate matter - that is why large scale adoption of battery electric vehicles (BEVs), which tend to be heavier than internal combustion engine vehicles (ICEVs), will not reduce tyre or road wear.  However, in urban driving, BEVs will almost totally eliminate brake wear due to regenerative braking - for example, BMW i3 does not generate any brake dust for 90% of the time. 
Fuel Cell Electric Vehicles (FCEVs) are much lighter and hold good promise over battery electric vehicles (BEVs) in reducing non-exhaust emissions of PM2.5.

Other measures for reducing PM2.5 emissions could be the use of drones for delivery of parcels in the city and use of Internet to send documents instead of paper.  Both will reduce the number of vehicles on the road.

Greater use of public transport will help too as well as pedestrianisation of central city areas to exclude road traffic.  

Self-driving electrical vehicles (AEVs) will be much lighter than today's BEVs.  As a taxi service, AEVs can be right size for the purpose - for example, for transporting one or two people, a two-seater AEV is all that is required.  Due to their better safety characteristics, AEVs can be made of lighter materials saving on fuel and reducing PM2.5 emissions from tyre and road wear.  Introduction of AEVs will also reduce the number of vehicles in the urban surroundings. 

Most big cities have a subway system where ventilation is not very efficient and the air quality tends to be poorer.  Non-exhaust emissions are the most important source of airborne particulate matter in the subway system, including platforms and trains. Subway PMs are mostly iron and carbon based particles and are generated from rail-wheel-brake interfaces.  Trains and ventilation systems drive the particles along the tunnel and mix them with dust etc. More effective ventilation systems, magnetic filters and platform screen doors will help to reduce the concentration of PMs on the subway platforms.