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Diary, February 2021

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Monday, February 1, 2021

Palindrome date D-M-YY, double date M/D/YY and YY.M.D

Today is a palindrome date for the format D-M-YY: 1-2-21 and a double date for the formats M/D/YY and YY.D.M: 2/1/21 and 21.2.1.

Thursday, February 4, 2021

Winter is coming!

The weather predictions are becoming more and more convincing that we here in the Netherlands are heading for a winter period. For Sunday, about 10 to 20 cm of snow is expected, followed by a week of cold temperatures. At the end of the week, there could be 10 cm of ice in the North of the country.

Sunday, February 7, 2021

About 15cm of snow

It already started to snow yesterday evening. This morning, I tried to measure the height of the snow on a table outside. It is difficult to establish the amount of snow that fell because there is a strong wind which blows the snow away. I measured the snow height on two spots and concluded that about 15cm of snow has felt during the night. It is still snowing and it will continue snowing during the day, the night and also tomorrow according to the weather predictions. According to the weather predictions the coming weeks the temperatures will remain below zero (Celsius), meaning that the snow will not melt away and stay on the fields for a long time. My estimate is that during the day another 3cm of snow fell.

Monday, February 8, 2021

Some more snow

Today, there is going to be some more snow. A bigger problem is that the temperature is going to drop and stay below zero (Celsius), which causes the snow to stay. Often, snow happens at the end of a cold period in the Netherlands. Now it is at the start of a cold period. The last predictions are that the temperature will stay below zero for at least a week. This morning, it took me a quarter of an hour to get the car out of a parking lot. I have some snow dunes in my back garden. My estimate is that during the day (since yesterday evening) about 4cm of snow fell.

Tuesday, February 9, 2021

Some snow

In the morning, some more snow fell. I think, not more than one centimeter. The sun started to shine during the day.

Wednesday, February 10, 2020

Double date

Today is a double date when the date is written in the format MM/DD/YY or YY.MM.DD: 02/10/21 or 21.02.10. The next such date is on December 11 this year. This is the third mention of a special date for this year.

Some snow

Again, some snow fell during the morning. It is now the fifth day in a row that it is snowing, which is quite unique.

Thursday, February 11, 2021


At 23:52, I bought the book Environments written by Frans Haks, Egbert Switters, and Swip Stolk in Dutch, published by Studium Generale Rijksuniversiteit Utrecht in 1968. I bought it online from De Slegte, Antwerpen for € 100.00.

Friday, February 12, 2021

愉快的春节 and palindrome date

Today is the first day of the year 4718, the year of the ox according to the Chinese calendar. The spring festival has begun. This is both the year of Andy and I, meaning that this year we will have our 24th and 60th birthdays, respecitively. Today is also a palindrome date when written like 12/02/2021 (DD-MM-YYYY), 12-2-21 (DD-M-YY), and 21.2.12 (YY.M.DD).

Sunday, February 14, 2021

Animals tracks and snow shapes

In the afternoon, Conny and I walked along the roads called Moorveenweg, Hegebeenkweg, Berktepaalweg/Kwekerijweg, Riethermsteeg, and Ontginingsweg. The name of Berktepaalweg refers to the marke stone called Berktepaal. But this stone is not along this road, but along the road called Moorveenweg which runs parallel to it. The road called Bertkepaalweg was only extended to the border between the municipalities of Enschede and Haaksbergen around 1937. So maybe the road was called like this, because it was going into the direction of the Berktepaal. We saw many animals tracks in the snow, most of which seems to be from rabbits and/or hares and maybe also deers. Conny took a picture of what looked like a hare in the distance and one of what looked like a deer in the distance. We also saw many examples of snow shaped by the wind. Surprising how just a small tree can lead to dunes in the wake of the tree. The picture above is of such a dune. I suspect that turbulence plays some role in the development of these dunes.

Tuesday, February 16, 2021

Data modeling in Thinkwise

I watched the first half of the video Platform Experience - On demand (in Dutch) on the Thinkwise channel. Thinkwise is a developer of low-code development platform, a platform that they for 16 years used to develop solutions for their customers, but in the past two years are marketing as a development platform. During the presentation, they said that the documentation is available online. I looked up their data modeling and was a little disappointed that it is table oriented. It was interesting to read the data modeling guidelines. It is interesting to read about strong entities, weak entities, link tables and inheritance tables, but it shows that the table oriented approach is an implementation of a more abstract way of modeling data. It seems they do advocate composite, and possible large, primary keys, which could not always be the best implementation solution. But it seems to work for the kind of applications that they target.

Friday, February 19, 2021


It seems that the battle against COVID-19 is a lost battle. Take for example, the scientific publication Mechanistic transmission modeling of COVID-19 on the Diamond Princess cruise ship demonstrates the importance of aerosol transmission, which suggest that it is very difficult to stop the spread of the virus. As expected, the virus is mutating and possible avoiding antibodies against earlier infections including antibodies produced by vaccinations. And now the first hybrid has been found, which combines the mutations from two variants, B.1.1.7 and B.1.429. There is no reason why this will happen again. Some specialist are stating that a cytokine storm plays an important role in people getting seriously ill from a COVID-19 infection. Maybe more effort should be put in treating that. One such possible treatment is the EXO-CD24 drug found by Prof. Nadir Arber. The effectiveness of this drug has not been scientifically established yet by means of double-blind study with sufficient number of cases.

Saturday, February 20, 2021

Walking along the border

Conny and I decided to walk along the border near the city of Overdinkel. We first made a stop at the border between the village Glane and Gronau to find a border pole we missed last year May 31. When we parked our car, Conny noted stone that looked like a border pole and when walked over, was indeed the border pole 856-E. After we found the border pole we came for, we walked in the other direction and found one more pole. From there we drove to another location and walked a long distance along the border. At a tree, just after border pole 3-I, that had recently fell down, we had some lunch. The poles we encountered are:

Sunday, February 21, 2021

18° Celsius

The temperature at Twenthe Airport went up to 18.0° Celsius, which breaks the previous record of 15.1° for the temperature on this date in 1990. Quite surprising swing of weather, because two weeks ago was the start of a cold period where the temperature remained below zero Celsius for almost a week. Conny and I continued our search for border poles in Drenthe. The poles we encountered are: At home, Conny made curly kail hotchpotch with a spice mixture, consisting of onion powder, celery leaf, paprika powder, ground mustard seed, caraway seed, savory, thyme, basil, garlic powder, ground white pepper, ground black pepper, ground nutmeg, turmeric, ground cumin seed, ground bay leaf and ground coriander. It tasted nice.

Monday, February 22, 2021

16.7° Celsius

The temperature at Twenthe Airport went up to 16.7° Celsius, which breaks the previous record of 14.4° for the temperature on this date in 1966.

Tuesday, February 23, 2021

18.3° Celsius

The temperature at Twenthe Airport went up to 18.3° Celsius, which breaks the previous record of 14.4° for the temperature on this date in 1990. When walking, we still found some snow in a ditch along the road, which is a strange experience with the extreme high temperatures of these days.

Wednesday, February 24, 2021

18.5° Celsius

The temperature at Twenthe Airport went up to 18.5° Celsius, which breaks the previous record of 16.8° for the temperature on this date in 1990. This is the fourth day in a row, and probably the last, with a new record high temperature. The highest temperature for tomorrow is 17.9° Celsius which was measured in 2019. With a predicted highest temperature of 15.4° Celsius it is not likely that it will be broken.

Saturday, February 27, 2021

Border poles

This morning, Conny and I went walking along the border looking for the first border pole along the border of the province of Overijssel and Germany. The border of Germany makes a sharp turn to the South where the border of Overijssel continues towards the West. South of this border is the province of Gelderland. This border pole is called Jurisdictiepaal. It is placed there in 1766 as a replacement of a wooden pole. The pole played an important role in a border conflict between the marke of Haaksbergen and Honesch, which lasted from 1611 till 1773. The pole has the coats of arms of Gelderland (with date 1766 below it), Overijssel (with the date 1773 below it), and Münster. It is the first of 186 stones at the border of Guelders and Müster, which were placed after the convention of Burlo on October 19, 1765. We encounteret the following poles/stones: Link:

Sunday, February 28, 2021

Continue along the border

Conny and I continued our search for border poles along the border where we started yesterday. We skipped some part of the border because some stones are in the middle of a nature reserve and thus not accessible for the public. We encountered the following poles/stones: Near pole 833B we also found a German Trigonometric Point.

This months interesting links

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