COVID-19 numbers

In a time like this, there is much uncertainty. It may be the first time that the world is experiencing such a pandemic, but similar situations have been encountered before. People have lots of questions and they are looking for information. Unfortunately, there is a lot of misleading information available. It seems that most people don’t check such information. They just believe what they read. It is for this reason tragic when “official” websites provide misleading information.

One example is the incorrect representations of numerical quantities about the COVID-19 pandemic. Two such quantities that is for obvious reasons quite important for people is the recovery rate and the mortality rate. They give an estimate, based on the currently available statistics, of the chances for a person to recover or die from COVID-19, given that the person has contracted the decease.

The statistics, which is generally available (see for example Wikipedia), consist of three numbers provided for every country on a daily basis. These number are: the number of confirmed cases (CC), the number of deaths (D) and the number of recoveries (R). For example, on 14 June 2020, the quoted number for the whole world are:

CC = 7 763 921
D = 429 632
R = 3 682 950

From these numbers, one can now compute the mortality rate and the recovery rate. The mistake that one often finds is that these rates are computed by dividing D or R by CC. That gives a misleading result, because CC also contains the currently active cases that does not form part of D or R yet.

The correct way to compute the mortality rate is to divide D by the sum of D and R and multiply the result by 100 to express it as a percentage. In a similar way, the recovery rate is obtained to dividing R by the sum of D and R and then multiply it by 100. You will note that when you add up the mortality rate and the recovery rate you get 100%. That makes sense, because one would either die or recover. There is no other option.

Applying these calculations to the above statistics for the world, we find the mortality rate to be just over 10% and the recovery rate just under 90%. These rates differ from country to country. For instance, the current morality rate in the USA is about 15%, while for SA it is only 3.7%.

Why is it different for the different countries? This is an important question, because it affects people’s behavior. There are many possible reasons, including the age demographic of a country and the availability of medical facilities in the country. The mortality rates for different age groups are different: it increases for older people. If the number of active cases becomes too high, there may not be enough hospital beds and equipment to treat all those that need treatment. As a result, one can expect the morality rate to increase.

The government of a country needs to try and keep the number of active cases low enough so that those that need to treatment can get it. For that reason, they impose restrictions that are aimed to reduce the rate at which the virus is spreading. Restrictions may seem to be a violation of people’s freedom, but in this case it is necessary. However, a government can only do so much. If the people decide to ignore the regulations imposed by the government, because they want to exercise their freedom, then the virus would spread too fast, with the result that the number of active cases can increase above the level where the country would have enough medical facilities.

There are more numbers that are important, for instance the growth rate in the number of confirmed cases. That is a topic for another day.

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Lockdown fits me like a glove

Previous posts not withstanding, now that I’ve been living in this state of lockdown for more than a month, I realize that it is not so bad. In fact, when I hear how others are freaking out and protesting the current situation, my reaction is something like “really??!!”. Then I remember that, when it comes to normal humanity, I’m probably a bit of an outsider.

It helps to be an introvert, which means that alone-time is always valued much higher than time with people. Make no mistaken, I do enjoy the occasional social time with friends or family, but too much of that drains my energy and makes me feel awkward.

However, being an introvert is not enough to help one enjoy lockdown. There is this one dangerous condition called boredom that afflicts most people in lockdown, leading to cabin fever and then to all sorts of other things that we need not elaborate on.


So what would be an effective way to counter boredom? One would need lots of things to do. Many people perform what they call “spring cleaning.” (However, if you think about it, cleaning during lockdown is the opposite of spring cleaning.)

There are other activities that one may become involved with due to the lockdown such as cooking. However, if cooking was not part of you daily routine and if it does not suddenly become a new found passion, then it can soon develop into a onerous chore. The same applies to many other chores that are suddenly imposed on one by the lockdown situation.

So what would then be an effective activity to counter boredom? The answer is flow. You need something that you are passionate about, something that involves activities that challenge you, but for which you are capable to meet these challenges. It can keep you busy for hours. While you are doing it, you enter a state of flow; you don’t even realize that time is flying by. Instead, you are completely focussed on what you are doing. And you enjoy it!

My passion is theoretical physics research. When I’m busy performing those calculations or developing those derivations, I am almost unaware of anything else going on in the world. The activity puts me in a positive frame of mind and keeps me there for the duration of the activity.

It is a good thing that I have embarked on a particular challenging project just before lockdown started. There are times that I don’t have anything interesting and challenging to work on, but now I do. My setup at home is perfectly geared to perform this work. In fact, it is even better than at work. So, I’m glad for the opportunity that lockdown provides me to do this work. I hope I can finish it before lockdown is lifted to the point where I need to go back to work.

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Neutrino dust

It is the current understanding that the universe came into being in a hot big bang event. All matter initially existed as a very hot “soup” (or plasma) of charged particles – protons and electrons. The neutral atom (mostly hydrogen) only appeared after the soup cooled off a bit. At that point, the light that was produced by the thermal radiation of the hot matter had a chance to escape being directly re-absorbed.

Much of that light is still around today. We call it the microwave background radiation, because today that light has turned into microwave radiation as a result of being extremely Doppler-shifted toward low frequencies. The extreme Doppler-shift is caused by the expansion of the universe that happened since the origin of the microwave background radiation.

It is reasonable to assume that the very energetic conditions that existed during the big bang would have caused some of the hydrogen nuclei (protons) to combine in a fusion process to form helium nuclei. At the same time, some of the protons are converted to neutrons. The weak interaction mediates this process and it produces a neutrino, the lightest matter particle (fermion) that we know of.

So what happened to all these neutrinos? They were emitted at the same time or even before the light that caused the microwave background radiation. Since neutrinos are so light, their velocities are close to that of the speed of light. While expansion of the universe causes the light to be red-shifted, it also causes the neutrinos, which have a small mass to be slowed down. (Light never slows down, it always propagates at the speed of light.) Eventually these neutrinos are so slow that they are effectively stationary with respect to the local region in space. At this point they become dust, drifting along aimlessly in space.

While, since they do have mass, the neutrinos will be attracted by massive objects like the galaxies. So, the moment their velocities fall below the escape velocity of a nearby galaxy, they will become gravitationally bound to that galaxy. However, since they do not interact very strongly with matter, they will keep on orbiting these galaxies. So the neutrino dust will become clouds of dust in the vicinity of galaxies.

Hubble Space Telescope observes diffuse starlight in Galaxy Cluster Abell S1063NASAESA, and M. Montes (University of New South Wales)

Could the neutrino dust be the dark matter that we are looking for? Due to their small mass and the ratio of protons to neutrons in the universe, it is unlikely that there would be enough neutrinos to account for the missing mass attributed to dark matter. The ordinary neutrino dust would contribute to the effect of dark matter, but may not solve the whole problem.

There are some speculations that the three neutrinos may not be the only neutrinos that exist. Some theories also consider the possibility that an additional sterile neutrino exists. These sterile neutrinos could have large masses. For this reason, they have been considered as candidates for the dark matter. How these heavy neutrinos would have been produced is not clear, but, if they were produced during the big bang, they would also have undergone the same slow-down and eventually be converted into dust. So, it could be that there are a lot of them drifting around aimlessly through space.

Interesting, don’t you think?


Finally got things somewhat under control. Been letting the dust gather here for long enough. Not being among those with an aptitude for admin, I went through a bit of a struggle to get to this point. But here we are. Things are looking up.

So, what have I been busy with that allowed all the dust to gather? I wrote a book. Yes, that’s the one: How do we know what we know? It was quite the adventure, especially the publishing part. I decided to try the self-publication route. Over time I’d like to tell the tale of this adventure, and perhaps also some advice to those that wish to follow this path to publication.

The first question that I imagine anybody would ask is: why would you want to self-publish a book in the first place? The obvious answer may be that you may want to avoid all those challenges associated with getting a traditional publisher: finding a literary agent, writing a book proposal, and waiting for a year or so to get any response. On top of that, once you found a publisher that is interested, you have to sign away the copyright to your hard work and settle for a tiny portion of the income that comes with the sale of any book.

However, there are benefits in using a traditional publisher. They take over the responsibility of marketing the book. It does not mean that you are not involved, but you have help. In the case of self-publication, the marketing of the book is your responsibility.

Another benefit of a traditional publisher is credibility. Some types of books are refereed before they are physically published. Obviously, a self-published book does not necessarily go through the same process. So, when people decide to buy a book, they may be prejudiced against buying a self-published book, because they may feel its contents have not gone through the same verification process as a book from a traditional publisher. This issue does not affect all genres. So, it depends on the type of book that you want to publish.

Don’t forget about the editing! The traditional publisher would have professional editors to do the copy editing, proof reading, and so forth. When you self-publish, you need to find your own editors. That is a nightmare all by itself. Rather don’t publish the books without having it properly edited first.

When it comes to the design of the book, which includes the interior design and the cover design, the preference depends on what you want. The traditional publisher would have professional people doing the design, and apart from making some choices and giving approval, you may not have much direct involvement in this part of the process. Perhaps that’s how you prefer it. With self-publication you can also hire professionals to do the design, but you have the freedom to do it all yourself. If you are not very good with this, it could affect the success of your book. If the result is good, then you can be proud of having done it yourself.

In my case, the choice to follow the self-publication option, was based on the fact that I didn’t want to waste time on book proposals. Frankly, I don’t think I have enough of a “profile” to convince traditional publishers that a book I wrote will sell enough copies to make it worth their while. I also liked the freedom to do my one design. Whether the result is good enough to improve the sales remains to be seen. But even if I don’t sell so many of them, the adventure of doing it all myself (and all that I have learned in the process) makes it worth the trouble.

Feel holidays

Ever seen the Eiffel tower? No, not a photo of it. The real thing. With your own eyes. Was it a big deal? Or perhaps the Victoria falls? There are many things in this world to see and many people spend large amounts of money to go on trips to see these things. They would take photos when they are there and come back to tell everybody about how amazing that was. Perhaps that makes one feel … mmm, I should save up some money to go on a trip to see it myself. With my own eyes.

Well, due to the nature of my work, I often get opportunities to go some places. Some times these places include some amazing sights. Things that one has seen photos of and that are famous for some reason. For instance, not too long ago, I had the opportunity to go to Paris for a conference and then had some time to go sightseeing.

So there I found myself looking at the Eiffel tower with my own eyes. Yes, it is different from seeing a photo of it. One gets a real perspective of its size. One can also get a sense of its surroundings, which somehow adds to the sensation. I didn’t go up in the tower. That is not something I’d enjoy due to my fear of heights. So what else is there to do about it? Oh, I can take a photo or two, or ten if you like. So I did that. What else? Well that’s just it. Once you’ve seen it, took the pics, bought the t-shirt, perhaps went up, its done. Somehow all that leaves me a bit vacant.

It is not only the case for the Eiffel tower. Any sightseeing that may be associated with some famous place in the world just does not appeal to me that much. There is simply not so much to it for me. Perhaps other people feel differently about it. People often still have that wow-feeling that they had when they were small, but somehow I’ve lost that. I do not get wow-ed by seeing famous sights.

As a result, any holiday that is designed arround going to some place to do sightseeing simply does not succeed in being a great holiday for me. So, such expensive overseas trips are a complete waste of money, as far as I am concerned.

That does not mean that all overseas trip are like that. It depends what one is looking for. I’ve recently discovered a different kind of overseas trip. These trips are not about what you see but rather about what you feel. So I call them feel holidays. These holidays are for instance planned arround going to see friends or family that live in other countries. It makes one feel happy, feel companionship, feel love. Often one may feel emotions that one haven’t felt in a long while. That makes them worthy holidays for me, much more valuable than sightseeing holidays.

I’m currently having such a feel holiday. Perhaps I’ll tell you about it some other time.