Tuesday, 16 January 2018

Heat given off by a human body is about 100 Watt


Humans are warm-blooded mammals and their body temperature is maintained constant at about 37C. Comfortable ambient temperature is much cooler at about 20C.  We are constantly losing heat energy from the body at higher temperature to the  surroundings at a lower temperature.  The heat energy is lost by radiation, sweating and respiration.  That is why when a lot of people are present in a room, it feels warmer.

The body temperature is maintained at 37C by compensating the energy lost to the colder surroundings by converting the food we eat into energy. Heat is generated in biochemical reactions in cells (we say that food is burnt to produce energy). Each gram of carbohydrate generates 4 Calories, while fat and protein generate 9 and 4.5 Calories respectively.  In the end, all energy generated by  digesting food is converted into heat which needs to be lost to maintain a constant body temperature.

Therefore, energy given off by a human body in a day is equal to the energy produced by the food we eat per day.  We shall calculate this in the following:

Suppose, that every day one consumes 2000 Calories (Some eat much more and get obese!). We can calculate, using physics, the amount of energy produced in a day.
The Calorie used by nutritionists is actually equal to 1000 times the calorie used by physicist to measure energy. Note C and c in the two definitions of energy.


1 Calorie (used in nutrition) = 1000 calories or 1 kcal (used by physicists)

In physics the usual unit to express energy is a Joule (J), and 1 calorie = 4.18 J 
(One Joule is not a lot of energy - if we lift a 100 gram tomato from ground to 1 meter height then we have spent 1 Joule of energy).

So we consume 2000 Calories or 2000 x 1000 calories/day
= 2,000,000 calories/day
= 2,000,000 x 4.18 J/day
= 8,360,000 J/day

To make more sense of Joule per day, it is better to talk about power that is J per second or Watt (W). We divide J/day by the number of seconds in a day to obtain J/s or Watt.

A day has 24 x 3600 second = 86,400 seconds


We produce 8360000/86400 J per second (W) = 96.76 W (nearly 100 W) and this is eventually given off to the surroundings as heat.

10 humans will give off 1000W - that is like one bar of electric fire switched on!

A human gives off heat equal to that of a 100 W incandescent light bulb (old style light bulbs) which actually converts most of the electricity to heat.
The new style LED lights are much more efficient in converting electric energy to light and that is why they do not get hot when in use.  This also makes LED much cheaper to use for the same light output.

Your calorie consumption goes up if you are physically active, like running or climbing stairs than when you are sitting calmly. 
In one hour, a 68 kg man would burn, approximately, 70 Calories sitting; 85 Calories standing; 340 Calories walking at 6 km/hr and 700 Calories running at 10 km/hr.

Now you know why the room feels very warm when a lot of people are present and talking animatedly.
Or why you sweat and breath faster when jogging - you are burning extra Calories and producing heat faster.  The body has to get rid of the extra heat by sweating and respiration.

Final Word:  In this blog, we have calculated the heat produced by the food (2000 Calories per day) we consume  - essentially our metabolic rate (BMR) - and to a good approximation it is 100 W.  Under ideal conditions of comfortable environmental temperature, this energy is lost to the environment. The question I would like to address in my next blog is what happens when the outside temperatures are either too cold or too high for our thermal regulation mechanisms to work efficiently or not very well at all.  With climate change, heat strokes have become more wide spread and a good understanding of the science of heat strokes will be very useful - this is the subject of my next blog. 

Monday, 15 January 2018

Galileo Galilei - Family Tree, Friends and Foes


Galileo Galilei lived in Italy four hundred years ago.  He made some astonishing scientific discoveries which would be sufficient to rank him among the very best.  His impact on the scientific method - how a theory or hypothesis becomes established - was far-reaching.  Galileo emphasized the role of experimental verification of what a theory predicts as paramount for its acceptance.  Stephen Hawking calls Galileo the father of modern science.



Italy of the 16th and 17th century was a turbulent place with the Catholic Church fighting for its pre-eminent position against the onslaught of the forces of Reformation.  Having launched the Counter-Reformation, the Church was keen to suppress any dissenting voices and Galileo, with his research in astronomy, was sucked into this intrigue.  He paid a heavy price for demonstrating faith in his work and standing up for what he believed to be the real truth.  

I start by presenting the family tree of Galileo Galilei.   I also present a very brief political background of sixteenth century Italy and point out the relevant regions and cities.
(Click on the slide to view its full size image; press Escape key to return to the main text)






The history of Italy in the 16th century is characterized by foreign domination. Following the Italian Renaissance Wars (1494–1559), the south of Italy and the Duchy of Milan were controlled by Catholic Habsburg Spain.  The Republic of Venice, the Duchy of Florence, the Papal States and the Republic of Genoa remained independent.  The House of Medici was recognized as the ruling family of the Grand Duchy of Tuscany by Pope Pius V.
The Papal States launched the Counter-Reformation, which lasted from the Council of Trent (1545-1563) to the Peace of Westphalia in 1648 to end the Thirty Years’ War fought in Central Europe resulting in eight million fatalities. Initially a war between various Protestant and Catholic states in the fragmented Holy Roman Empire, it gradually developed into a more general conflict involving most of the great powers. The war became less about religion and more of a continuation of the France–Habsburg rivalry for European political pre-eminence.
The Inquisition was a group of institutions within the government system of the Catholic Church whose aim was to combat heresy. With the Protestant Reformation, Catholic authorities in the Vatican became much more ready to suspect heresy in any new ideas. In 1542 Pope Paul III established the Congregation of the Holy Office of the Inquisition. It had the tasks of maintaining and defending the integrity of the faith and of examining and condemning/outlawing errors and false doctrines; it thus became the supervisory body of local Inquisitions. Arguably,  the most famous case tried by the Roman Inquisition was that of Galileo Galilei in 1633.  



There are some detailed accounts online (1, 2) and good books (3) describing Galileo's scientific work.  I give a brief introduction in the following two slides.












Most scientists work very hard on the subject they love but by and large they operate in a benign environment.  May be not well paid but they are able to have a lifestyle that suits them best to pursue their research without interference from politics and other social/religious matters.  
Galileo did not have such luxury - he was short of money during the first half of his life with a big family to support.  His work was in direct conflict with the powerful Catholic Church and was hounded for 30 years by the religious mafia.  It is to Galileo's credit that in such an environment he was able to produce scientific work of such great merit and change the way science was to be practiced in future years.

Sunday, 12 November 2017

Solar Energy and Micro Combined Heat and Power Systems Will Bring Energy and Its Related Benefits to Villages in Developing Countries


Energy is the ability of a system to do work. Power is the rate of doing work and is equal to the change in energy per second.  Energy is measured in Joules, Power in Watts.  1 Watt = 1 Joule per second 

Access to energy serves as the base of the pyramid on which foundations of education, health and employment can be built upon.  It provides basic human dignity to people...

Globally, more than 1 billion people have no access to electricity - they are energy-poor and live mostly in Africa and remote rural locations in developing countries.  Energy is potentially available in these places but is not harnessed to benefit the populations.  For example:  Africa has accessible 10,000 GW of solar power, 300 GW of hydro power and 100 GW of wind power (1 GW = 1 billion Watts).  With technological advances, now it is possible to exploit these resources for the benefit of local populations and make a real difference to their lives.

The paradigm shift has been due to:  
(a) the development of renewable energy sources - particularly solar energy - which is now able to provide local, small scale energy generation with a cost that can be equal to or even less than coal and oil produced energy. 
(b)  Light-Emitting Diodes (LED) convert electricity into light with very high efficiency  that is about 12 times better than the old style incandescent light bulbs.  LED also last on average 20 times longer  and do not require frequent replacement.
(c) Battery Storage: Solar energy is only available during daylight hours. New efficient and cheaper batteries now allow storage of extra electricity produced during the day for later use. 
(d) Access to internet in even remote places - this allows great strides to be made in education, business and social inclusion for otherwise isolated populations. 
(e) Micro-grids: Blockchain allows members of a community to reliably sell and buy electricity from each other using micro-grid structures. This provides the possibility of uninterrupted supply at reasonable cost.

I shall look at local power generation where your home essentially becomes a power plant.  With a micro-grid system using some storage batteries and blockchain technology, communities can become independent of the national grid systems which, in a lot of cases, are not fit for purpose anymore and are hugely expensive to modernize. For example, in Puerto Rico, even after a month of Hurricane Maria, 85% of the population has no electricity - a stark example of the failure of centralized power generation and transmission.   National grids are also vulnerable to cyber attacks which can result in power loss for millions of people.
There is a strong case for the adoption of local power generation systems globally - in developed countries too - and I feel that that is the way future will unfold. In some ways they are already here and we shall look at a case study of a mountain village in India where people are already producing their own solar energy that has transformed their lives for the better.

National Power Plants and Distribution Grids:  Globally, energy is produced in big power plants (some supply energy to a million homes) which is then transmitted via a grid system to consumers.  Power plants are expensive to build - cost billions and most plants use fossil fuel that is expensive,  polluting and responsible for much of the recent global warming.  The residential and business consumers may be very far away from the production site and transmission lines (grid) can be very expensive to build and maintain.  Transmission of electricity over large distances causes serious losses of the order of 8 to 10% reducing the overall conversion efficiency of power plants.
Governments have subsidized fossil fuels for a long time and continue to do so.  This has impacted on the development of alternate energy sources like renewable solar and wind energy.  The main advantage that the current power plants have is their ability to produce power continuously and adjust their output to meet the varying demands over the course of a 24 hour day. 
There is much wrong with the aging transmission infrastructure in most countries.  I do not wish to digress here but refer you to many relevant publications (1, 2, 3, 4).
In developing countries, the national grids do not supply the whole countries and many regions are not served.  240 million Indians have no electricity in 2017.  
Extending the grid to full geographic coverage is hugely expensive and not expected to happen any time soon or ever. 

Micro Combined Heat and Power (mCHP) Systems: At times, solar and wind energy generation may have gaps - for example if the weather stays cloudy for an extended period of time or during the rainy season, solar panels will not produce much, if any, electricity.  In these situations, one will need to either connect to the grid (if it is available) or generate energy using conventional fuels like natural gas.  
A small generator system which can supply both heat (for space heating) and electricity (to run home utilities) works on the technology of fuel cells. A good example is the proton-exchange membrane (PEM) fuel cell which can supply 1 to 10 kW with a high efficiency of 90%.  Fuel cells have no moving parts, very quiet and require little or no maintenance. They cost about $450 per kW of installed capacity and last 50,000 hours.   

A mCHP generator may follow heat demand and deliver electricity as a by-product, or may follow electrical demand to generate heat as a by-product - and heat and electricity are produced at the location where they are needed and when they are needed (at times when solar panels output is low).  
In large scale power plants, electricity production efficiency is about 35% and waste heat is generally thrown away.  mCHP can also help to reduce the energy bills by a large amount, is environmentally friendly and provides independence from the grid.  It is expected that mCHP system uptake will be high in developed countries as well where they will replace the conventional methods of space heating.  Batteries to store electricity are now priced so that one can think of installing these to save any excess power generated during the day.  Also electric car batteries will be ideally suited for this purpose and with more households owning electrical vehicles, storage batteries will be readily available.

Microgrids are isolated systems which generate power on-site.  They are insulated from the problems faced by national grids for which in the case of a disaster striking (due to weather, cyberattack, component failure etc.) most consumers will be affected and it can take a long time for the power to be restored.  In microgrids, the damage is limited and most people will continue to have electricity available.   

Solar Energy is Already Making A difference in India:  Jaideep Bansal is a leader in Global Himalayan Expedition - an Indian Social Enterprise working towards providing energy access to remote mountain communities.  India has been able to achieve a smaller price per watt for solar than coal.
Bansal describes how the villagers are using decentralized micro-grids to power up houses with LED lightning technology.  They are able to generate enough electricity with a small solar panel and battery to power up 10 LED lights, one street light, 1 LED TV, 2 fans and mobile-charging points!

Blockchain technology further allows trading of electricity among neighbours.  Blockchain is a new system of carrying out transaction among a group of people.  According to Wiki:

A blockchain can serve as "an open, distributed ledger that can record transactions between two parties efficiently and in a verifiable and permanent way." For use as a distributed ledger, a blockchain is typically managed by a peer-to-peer network collectively adhering to a protocol for validating new blocks. Once recorded, the data in any given block cannot be altered retroactively without the alteration of all subsequent blocks, which requires collusion of the network majority
This is already happening.  I show the next slide which describes Bansal's thoughts on how such trading can proceed:

It is not only in providing energy to communities, solar energy is making a huge impact on other parts of life in developing countries.  The price of solar panels continues to drop and it is hoped that in not too distant future, most of the people in the world will have reliable electricity forming a firm base of the pyramid on which they can build their lives.

I acknowledge some recent publications from the World Economic Forum which encouraged me to write this blog. The publications have been referred to at appropriate places in the text.

Tuesday, 31 October 2017

Orbital Period Decrease of Binary Pulsar PSR B1913+16 - an Update


Recent detection of gravitational waves (GW) by LIGO has provided a direct and firm test of the validity of Einstein's theory of general relativity.  GWs detected in August 2017 were produced by the collision of two neutron stars about 130 million light years from the Earth.  Neutron stars had a diameter of about 20 km but were 1.17 and 1.60 times more massive than our Sun.  Some of the mass is converted into energy as the neutron stars spiralled  to merger.  This energy was radiated in the form of particles, electromagnetic (EM) and GW waves.  EM waves were detected by a number of observatories and GW were detected by the LIGO laboratories.

Indirect evidence of the validity of the General Theory had been accumulating over the past 100 years starting in 1919  when Eddington observed the bending of light from a distant star passing near the Sun.  The light was found to bend by the amount predicted by Einstein.  

The strongest evidence was obtained through the observation on binary pulsars - two neutron stars rotating around each other.  The first binary pulsar system, PSR B1913+16, was detected by Joseph Taylor and Russell Hulse in 1974.  They were awarded the 1993 Nobel Prize for finding the pulsar system. 

The two neutron stars in the binary pulsar are 1.438 and 1,390 times the mass of our Sun.  The binary pulsar PSR B1913+16 is 21000 light years from the Earth. The elliptical orbit has an eccentricity equal to 0.617 and a semi-major axis equal to 1.95 million km.  The neutron stars complete a rotation in 7 hours and 45 minutes.  The rotation distorts spacetime in the vicinity and energy is radiated out as gravitational waves.  Einstein's theory predicts the exact amount of GW radiation that would be emitted.  The radiated energy is lost from the rotational energy of the binary pulsar system and neutron stars get progressively closer. The observed change in orbit parameters (the semi-major axis is decreasing by 3.5 meters per year) provides the point of comparison with the prediction of the General Theory. It is estimated that it will take about 300 million years before the neutron stars merge.  

Continued observations of the binary pulsar has provided valuable data that have been published in a series of papers - the latest by Weisberg and Huang in The Astrophysical Journal 829:55, 20 September 2016.  The new data confirms the previous agreement with the General Theory.  This is shown in the following slide:

Several other binary pulsars have been studied since the discovery of PSR B1913+16.  Observations from these also confirm the validity of the General Theory of Relativity, albeit with somewhat lower accuracy.

I am indebted to Professor Joseph Taylor for permission to use the orbital decay figure.

Monday, 30 October 2017

The Disease Called Obesity - What is it? - Why? - Can it be Controlled? A Community Education Feature


Obese people are up to 80 times more likely to develop type 2 diabetes than those with a BMI of less than 22                        ...DiabetesUK

In 2013 the American Medical Association started clas­sifying obesity as a disease, a decision that still generates debate. The American Heart Association, the College of Cardiology, and the Obesity Society have also announced that obesity should be treated as a chronic disease.

Obesity is a global phenomenon: After tens of thousands of human generations since evolution, obesity worldwide has only become widespread in the past 50 years - increasing more than six-fold since 1975 - the obesity epidemic came with astonishing speed.  Obesity is expected to get much more prevalent over the coming decades with 2 in 3 adults turning obese in some countries by 2030.  A good animation  of how obesity has spread globally since 1972 may be seen here.

You are obese if you weigh 20% or more than the normal weight for your height -  i.e. if you have a body mass index (BMI) greater than 30. BMI is calculated by dividing your weight by the square of your height.  A BMI of 30 makes you obese - the acceptable range is 19 to 25.

To be obese is like carrying a 15 kg suitcase everywhere you go - traveling or not !!   Morbidly obese carry 50 kg extra weight 24 hours a day.  What the extra baggage does to your body is not difficult to guess.


Following slides summarize the situation:

In the table, numbers are in millions; Obese in blue and severely obese in red:

More and more children are getting obese too - at a much faster rate than adults!



Obesity is not good for you; obese people have increased  risk of many medical conditions like:
High Blood Pressure, Diabetes, Gout, Heart disease, Strokes, some Cancers, Joint problems, Osteoarthritis, Breathing problems, problems with sleep, Gallstones and more.  
The association between obesity and depression is also well established. 
For obese people, a higher BMI indicates that they are more likely to have medical problems and of greater severity.  In the slide above, we have seen massive increases in the number of severely obese people (with BMI greater than 35) and this does not portend well for global health. I show the projections of how obesity is expected to increase in future: 


The most comprehensive analysis of the relationship between BMI and mortality has been carried out by the Global BMI Mortality Collaboration which involves 500 investigators from over 300 institutions.  They analysed 4 million individuals who never smoked and had no existing chronic diseases at the start of the study.  Data from 10.6 million participants from 239 studies conducted between 1970 and 2015 in 32 countries formed the database.  A total of 1.6 million deaths were recorded during this period.  In the four continents studied, the association of both overweight and obesity with higher mortality were broadly consistent.  
The slides summarize the results (In the slides, Hazard Ratio HR is a measure of mortality risk: an HR of 2 for a BMI group means that the risk of dying is two times the risk for the reference group shown by down-pointing arrows) 




An alternate way of looking at the data is provided by a recent analysis, published in the journal Nature (2017), of over 600,000 people.  It concludes that a unit increase in the BMI value reduces lifespan by 7 months.  Obese (BMI = 30) will lose 3 years while morbidly obese (BMI = 40) will lose 9 years in lifespan. This is an eye-opener.

It is not only that the risk of mortality is greatly increased for obese people, their quality of life is also seriously impaired.

It is clear to me that obesity is a scrouge for global wellbeing and it is imperative that we find ways to control it.  I shall show in the following that the prevailing obesogenic environment coupled with Big Food interests creates a toxic mix that prevents effective measures to be put in place for rolling back what some people call the obesity pandemic.

Many initiatives have indeed been tried by authorities with little or no impact on obesity numbers. It seems that the problem of obesity, with all its negative impacts, is not going to go away.  In the following, first we shall try to understand the reasons that have caused the obesity numbers to get out of hand, why measures to control it have failed  and then look at the options we have.

Why is Obesity Increasing?  With all the problems with obesity, why is it not controlled?  Only a very small percentage of the population was obese fifty years ago.  It must be avoidable except in the few who suffer from certain medical conditions.  Obesity is a recent phenomenon and we need to look at the changes in society since about 1960.

Obesity is not natural - if we look around, we find that it is only the humans and their pets who are obese. We do not see obese animals in the wild.  

Increase in obesity is a multifaceted issue and depends on the prevailing socio-economic environment. I can think of some factors like globalization, industrial practices, changes in food products, eating habits, lifestyle changes - all of which affect the way we live and eat. 

On the simplest level, weight gain is determined by the following energy equation:
Weight Gain = Calories In - Calories Out
 We are indeed consuming more calories now than we were fifty years ago.  In the USA, average daily energy intake has increased by over 420 Calories or roughly 20% since 1970.  This translates into a gain of 4 pounds per month or about 20 kg per year.  The situation in many middle-income countries like China and India is even more serious where they have been changing over to western style diet of much greater processed food and ingredients containing greater proportions of fat and sugar.  
Consumption of sugar has gone up enormously over the past 300 years and is some four times higher than the WHO guideline of 50 gm per day; (see also). Obesity rates shown in the slide are for non-hispanic white population in USA in the age range from 60 to 69 years.
    
A word of caution here about inferring that sugar caused the increased obesity - while there is some correlation in increased sugar consumption and rise in obesity;  this does not prove that sugar is the only factor responsible for this increase. For a healthy balanced diet, I do feel that sugar intake should not be greater than the guideline of 50 gm/day - this will indeed require a big change in the choices of food we make today. To reduce sugar consumption below 50 gm/day is very very difficult and is not a practical proposition.

Since the middle of the twentieth century, many factors have affected the way we live and the way we eat our food.  Lifestyle changes have been enormous.  Traditionally, families used to eat out one or two times per week.  Now, 50% of our meals are eaten in restaurants.  Even food cooked at home is largely precooked and purchased in supermarkets.  These meals are high in salt, sugar, fats and preservatives - they also contain much higher calories than home cooked meals prepared from fresh ingredients.  
When families eat out, they consume more calories than when eating at home.  The food in restaurants tends to have more bad calories of fat and sugar.  (Click on the slide to see full page image)

The obvious question one asks - why do people consume more bad calories when they know that this will make them obese in the long term?  Surveys have shown that even obese people do not generally like the way other obese people look.  Many normal build persons definitely feel rather poorly about obese people, and at times are verbally and on occasions known to be even physically  aggressive towards obese people (obesity or weight stigma - more on this later).  Most obese want to lose weight - they go on diets - but find it difficult if not impossible to lose weight.  It is not a matter of self control - obese definitely would prefer to get slimmer but they just do not seem to be able to shed the extra weight.  We need to look at other factors that are fueling the obesity epidemic.
I shall discuss a few reasons that obesity numbers have taken off since 1970.  The addictive nature of high sugar foods and adoption of an increasing more sedentary and stressful life-style are big hurdles in reducing obesity numbers. We also live in an obesogenic environment where food manufacturers, restaurants and supermarkets encourage us to consume more processed foods which are rich in fat and sugar content and have taste/flavour enhancers. Globalization has helped to spread the obesity epidemic to developing countries (1 2) which were relatively free from this problem.
Obesity and Addiction: To understand how sugar can be addictive, let us see how addiction is defined:
Addiction is a primary, chronic disease of brain reward, motivation, memory and related circuitry 
In addiction, the brain chemistry is altered in a way that it compels one to repeat a substance or activity despite harmful consequences.  (note the emphasis on harmful)
There is an increasing body of research that tells us that sugar could be as addictive as cocaine.  Sugar activates the reward centre in our brain much the same way that drugs do and provoke similar cravings, binging and withdrawal symptoms.  
Eating too much of sweet or fatty foods can cause long term changes in the brain circuits that control eating behaviour.  

Drugs have been used by humans for a very long time - historically chewing leaves of certain plants to relieve pain.  However, It appears that our brain circuitry evolved to promote food intake for survival and drug addiction is really hijacking some of these pathways.  

The addictive nature of sweet and fatty foods is widely accepted by professionals.  I give some links that go into more details of the mechanisms of addiction and worth a look to appreciate the similarity between drug abuse and obesity.  The links are: 1   2   3.
Obesity and Stress:  
Understanding Stress:  Stress is a condition where an environmental demand exceeds the natural regulatory capacity of an organism.  In an organism, most biochemical processes strive to maintain equilibrium (homeostasis - the organism's optimal condition for living); an ideal condition.  Environmental factors, internal or external stimuli continually disrupt homeostasis. Factors causing an organism's condition to diverge too far from homeostasis can be experienced as stress - factors like moving house or job, prolonged starvation, death of a loved one etc. can create a stress situation.  Both acute and chronic stress can lead to changes in behaviour and physiology resulting in conditions like depression, delusions and anxiety.
Stress levels have been increasing over recent times; A study claims that stress levels have soared by 30% in the past 30 years in USA.  
Much research is being carried out to understand link between stress and obesity.  A 2011 study reached the following conclusions:  When under stress 
  • the food reward system overrules homeostatic eating behaviour 
  • overweight subjects show increased 'wanting' of dessert and snacks
  • overweight subjects show increased energy intake in the absence of hunger 
An individual under stress is more at risk to falling prey to addiction and obesity

Genetic factors to obesity and stress response.....
https://www.medscape.com/viewarticle/887443

Obesity and Sedentary Life-Style:  Modern man spends 50-70% of his waking hours in  sedentary activity  - defined as activity conducted in a sitting or reclining position involving low energy expenditure.  25-45% of waking hours are spent in performing low intensity physical activity and less than 5% in medium/high intensity physical activity.  A typical American is sitting down for about 60% of the waking hours
Humans, as hunter-gatherers, evolved when they were engaged in prolonged physical activity;  modern lifestyle of excessive sedentary behaviour poses an independent risk factor for a wide range of medical problems such as obesity, diabetes mellitus, poor cardiovascular health and more. 
Generally, one gains weight if energy expenditure is less than the energy intake and we are now consuming more calories than ever before.  Sedentary life-style is characterized by low energy expenditure and is also implicated in the rise of obesity in the past 50 years or so.
But this is not the whole story.  The harm done by sedentary behaviour is not completely neutralised by consuming fewer calories or increasing medium to high physical activity during rest of the day - it is an independent risk factor.  It is recommended that during prolonged sitting periods, one takes short breaks to walk in order to reduce such risks. 
Obesity and Type 2 Diabetes: Obesity is a major factor in developing type 2 diabetes accounting for 80-85% of the risk.  Type 2 diabetes is a metabolic disorder that results in hyperglycemia (high blood glucose levels).  This is because in type 2 diabetes, the body (a) becomes ineffective at using insulin it has produced (insulin resistance) and/or (b) is unable to produce enough insulin. Over time, high blood glucose levels may damage the organs of the body.

Obesity and The Big Food:  The world has got into an impossible vicious circle.  The powerful food industry with a big purse worth several billion dollars to advertise their products and with far-reaching lobbying powers is hell-bent to increase their profits - selling sugar and fat loaded foods has proved successful in the past and there is not a lot of evidence that things are changing.  We have seen that giving up addiction to high calorie convenience meals is difficult to cure.  
Besides Big Food, other industries have sprung up in the past fifty years or so and benefited from the obesity pandemic.  The weight-watchers industry, dieting, gyms, drug manufacturers are some which readily come to mind.  Their numbers have exploded - professing to control your weight and make you healthier - but obesity and related health ailments have continued to rise in line with the profits they make.  
The Stigma of Obesity:  We live in a judgmental society - for better or worse - there is much pressure to look slim (BMI < 20 ??) with negative attributes assigned to overweight and obese people - attributes such as lazy, work shy, undisciplined, lacking will power and more.  Obesity stigma is prevalent in our society.  Health professionals, family members, media all are guilty of stigmatizing obese people.  A prevailing view is that it is the personal responsibility of the overweight to bring things under control and failure to lose weight is their fault - nobody else is there to blame.  Faced with this environment, it is not surprising that obese people feel let down and find it stressful and depressing to get on with their normal lives.
It is important that we, in the society, have a better understanding of obesity and empathize with obese people for the predicament they are in. 

How to Control Obesity: I do not think anybody has a complete answer but there are some obvious things that one can do to help the situation. Remember that childhood obesity is increasing at the fastest rate and excessive body fat causes physiological/metabolic changes which persist into adulthood.  As adults, today's obese children will find it even harder to lose weight.  We might not have seen the worst of the situation yet. Any measures to control obesity must address the childhood obesity.


One is up against the industrial giants who can outspend well-minded people - they also have 'expert' representations in the regulatory bodies who make the rules.  Somehow, the governments have to bring out binding regulations for food products - they did succeed in curbing smoking in public places although alcohol abuse has not been managed yet.  


Governments have to spend much more money in tackling obesity.  In the long run, the reduced cost of treating obesity related illnesses will more than compensate the extra spending directed to curb the problem.


Any measures aimed to reduce obesity must ensure that they do not require a serious sudden lifestyle change.  Weight reduction must be a gradual long term process otherwise the stress created by adjusting to a new routine will make it difficult to achieve success.  Reducing calorie intake must be a part of any weight reduction programme; but one only needs to reduce calories by say 10 or 15% each day to achieve significant benefits over the period of a few years.  


Some Obvious Measures: 
1.  Education/Awareness: Absolutely essential that the person involved understands what the problem is, what one wants to achieve and what her/his options are to do that. Also important to understand how the human body metabolizes food, calorie content of foods etc. - essentially a simple course in nutrition will be helpful. 
2.  Exercise: More physical activity must be encouraged. Free gym membership for obese people will help too.  But the main message has to be for the general public to appreciate the need to control weight by being more active and adopting a less sedentary lifestyle.
3. Regulatory Framework: Food advertising, labeling, marketing, pricing are all parts of regulatory framework.  Other measures like curbs on display of energy dense food in supermarkets, near schools etc will help. 
4. Foods to Avoid: People should be encouraged to avoid eating foods with lot of fat and sugar content and change to eating more fruits and vegetables. 

Reducing weight should be a stress free process otherwise it is bound to fail.  I have published some ideas how to lose weight in a stress free manner. 

There is only so much one can do in terms of education and regulation.  Eating is an individual choice - food has become more affordable; and has been made more addictive by Big Food.  It is a vicious cycle.  Personal responsibility, for what you eat and what weight you are, is important but not always under your control.

I would love to hear your thoughts on what can be done to control obesity. 

Sunday, 22 October 2017

Self-taught AlphaGoZero is the Best GO Player Ever !!

This is a truly amazing development...

On 15 March 2016, I had posted the following blog (click on it to go there)

Another Step towards Achieving Artificial General Intelligence: AlphaGo triumphs over the World Champion of the Game GO

GO is an ancient Chinese board game (458 BC) that is far more complex than Chess.  In March 2016, the program AlphaGo defeated the reigning world champion Lee Se-Dol in 4 out of 5 games.  Lee had remarked:  "I don't know what to say ... I kind of felt powerless".  AlphaGo has since had more notable successes.  
To beat world champions at the game of GO, the computer program AlphaGo had relied largely on supervised learning from millions of human moves - moves in GO that previous human players had used.

David Silver and colleagues have now produced a system called AlphaGoZero, an evolution of AlphaGo, that is the strongest GO player yet.  AlphaGoZero has defeated champion-beating AlphaGo with a score of 100 to 0 - 100% of the time!
The new program AlphaGoZero is based purely on reinforced learning and learns solely from self-play. Starting from completely random play, AlphaGoZero learns to play from scratch, simply by playing games against itself.  
It can reach superhuman level in just a couple of days training involving several million games of self-play.  It can now beat all previous versions of AlphaGo. 

It also learns quickly - It surpassed the version used to beat world GO champion Lee in 3 days of self learning.  
This is superhuman performance indeed!

David Silver explains his work in this youtube video.

The Editor of Nature writes:  Because the program has discovered the same fundamental principles of the game that took humans centuries to conceptualize, the work suggests that such principles have some universal character beyond human bias.

AlphaGoZero represents the evolution of computer programs (artificial intelligence - AI) from ANI (aritificial narrow intelligence) towards AGI (artificial general intelligence)(Click here to see my blog on how we define intelligence).

ANI is a task specific program and it works in a narrow domain with just a few simple rules.  In the game of GO, the domain is a 19 x 19 board (361 spaces) and the rules are very simple.  The program can explore all combinations of that small space by trying out and remembering the outcomes of millions of moves in a day.  This would be impossible for humans to achieve.  The program has far surpassed human capabilities in this regard. But, while excelling in the game of GO, AlphaGoZero is helpless if asked to do anything else - that is where it does not satisfy the AGI test.   ANI - yes; AGI - no.

The self learning aspect of the program is highly significant - this represents a breakthrough from the way computer programs have been developed in the past.  As the task rules and domains expand in scope, some sort of intelligence is bound to materialize from the complexity, and that will be a serious step towards achieving AGI - an intelligence par with humans. 

This will take time; But - remember exponential increase in technological progress.  The future may be a lot closer than we think!