School holiday activities for children stuck at home

Due to the circuit-breaker, most children are unfortunately stuck at home during their school holidays. Other than playing computer games, this article suggests other educational and fun activities for children and their parents: School holiday fun at home: Kids can go online to stargaze, study about animals, do science experiments.

The live stargazing activity of Science Centre sounds quite fun: https://www.facebook.com/183389296588/videos/2534433140205259/

Most of the activities are open to children outside Singapore as well!

Motivational: Take it one thing at a time

Source: https://medium.com/mind-cafe/four-habits-of-discipline-my-seal-dad-taught-me-7ed9b13987df

Just saw this article on Medium. Quite motivational and applicable to students and even working adults. There are 4 tips on the original website. We just quote one of the tips here. The Chinese equivalent, would be 千里之行，始于足下, or “A journey of a thousand miles begins with a single step”.

Enduring Work Ethic Stems From The Moment

I had an interesting conversation with him about Hell Week (some US SEAL army training week) a few years back.

For those who don’t know — Hell Week is ridiculous. You wake up on a Sunday to gunfire. You then work out until Friday with no sleep. Hell Week is the bottleneck that breaks a lot of talented people. It’s where the top 20% are whittled down to the top 5%.

I remember him saying, “Tuesday morning was the worst.”

It was a bizarre response. Tuesday? Wouldn’t Thursday be the worst? Or Friday morning? Then he explained and it made total sense.

You wake up on a Sunday morning at ~2 AM to gunfire. You run around getting yelled at. You are doing pushups, carrying logs, rolling in the sand. This continues all day, then into the night.

As people are sleeping in their warm beds, you continue exercising, shivering, and getting shouted at.

Monday morning comes. The drills repeat from sun up to sun down with non-stop exercise and physical torture. Then, all through the night, you do it again.

Then, Tuesday morning rolls around. You’ve gone more than two full nights without sleep. You’ve endured intense stress, cold water, and difficult exertion the whole time. By Tuesday morning, you’re more tired than you’ve ever been in your entire life.

That’s when you start to feel sorry for yourself.

“Oh man, it’s only Tuesday. How am I going to get through all of this?”

“If I’m this tired already…and I’m not even halfway through…”

The people that start thinking like this are the ones that quit.

The people who succeed — only look a few minutes in front of them. They don’t worry about Thursday or Friday. They are only focused on each individual exercise. They get through it one thing at a time.

You can apply this to many aspects of your life.

If you are studying for a massive test, take it one page at a time. Working on a huge presentation, one slide at a time.

For example, I swam in college. Our training was very grueling, 5 to 6 miles of swimming a day. Sometimes the coach would put a set on the board that made me think, “You’ve got to be f#$king kidding me. I’m going to die.” I just took it one lap at a time and got through it.

Lower your vision and piecemeal those big hurdles. It reduces the perceived mental weight of the tasks. Take it one thing at a time.

Rhodeus bitterling fish 鳑鲏鱼

I have never seen this fish before in Singapore. In China, it seems common. It is called “Pang Pi” fish, or Rhodeus /bitterling fish. Although it is not very colorful, it is quite unique due to its relationship to the clam.

As you can see from the video, it likes to hang around the clam/mussel, and it will even lay its eggs inside. Apparently, the clam also deposits its eggs on the “Pang Pi” fish.

Clams are hard to keep, and can be quite tricky for beginners. It is hard to tell if the clam has died or not. (Even an alive clam does not move much. You can see how it moves in the video.) Once the clam has died, it will start decomposing and producing toxins which may harm the entire tank. Also, it is quite common for clams to have parasites and worms in them.

The Spiritual & Humanitarian Aspects Of The Gospel – Homily by Archbishop William Goh

For the complete Mass recording go to: https://youtu.be/IzXhGM2QB8Q

The Church must never forget the priority of providing spiritual food to the People of God. This is critical and can never be replaced by mere humanitarian services. This was precisely what the early Christians did. They did not simply do humanitarian works when they cared for the poor and the widows. Their goal was ultimately spiritual. The works of mercy that they did were in continuation of Jesus’ works of mercy. They were meant to reveal the Father’s mercy and love for them. The gospel cannot be proclaimed without the works of charity, otherwise, it will merely be words. People need to see Christ and encounter His love and mercy concretely in their lives.

NUS High E-Open House

https://youtu.be/Ho5L5fAeNjU

The (promotional) video for NUS high open house is out! Parents and students who are interested to apply for NUS high are encouraged to watch it.

The actual open house will be on 15 May.

Mathtuition88

URL: https://www.nushigh.edu.sg/admissions/open-house

NUS High will be holding its E-Open House on 15th May. Do check it out!

NUS High is famous for its strong Math and Science curriculum. Many of their students are very strong in Math Olympiad and other Scientific topics.

E-Open House
15th May (Short Presentation and Q&A session with School Leaders, Alumni and Parents)

1st Session: 9:00 – 11:00 am
2nd Session: 2:00 – 4:00 pm

E-Engagement Sessions

1st Session: 19th May (Tue), 4:00 – 5:00 pm
2nd Session: 23rd May (Sat), 9:30 – 10:30 am
3rd Session: 23rd May (Sat), 2:30 – 3:30 pm
4th Session: 27th May (Wed), 4:00 – 5:00 pm

For further clarifications, please email: newton@highsch.nus.edu.sg

Also check out:

Update (provided by one of my Facebook readers):

NUS High School has put out its school presentation as part of its E-Open House on…

View original post 65 more words

How to free up space on Gmail

4 Steps to clear space in Gmail

Although Gmail has 15 GB of space, it can run out of space quite fast, especially nowadays many emails contain attachments that can be quite large.

To free up space on Gmail, I usually do the following 4 steps:

1) Search “size:100k older:2018” on Gmail

The above searches for files 100 kilobytes or larger, dated 2018 or earlier.

You can modify your search accordingly, for example “size:1M older:2017” searches for files larger than 1 megabyte, older than 2017.

2) Search “from:facebook.com”

The above searches for all email sent from email address ending with “facebook.com”. This can be quite effective, since many small emails typically end up being larger than 1 single big email.

You can modify your search accordingly, for example “from:twitter.com”, etc.

3) Delete unwanted emails (found using methods above), and clear Trash

Clearing trash is important (otherwise the deleted files will still take up space). Messages that have been in Trash more than 30 days will be automatically deleted though.

Double check before you delete, since once deleted it is not possible to recover the emails.

4) Refresh your browser, and see that you have more space!

Typically, by using the above steps, I can delete up to 1o0 MB of email.

Toy Poodle Pictures

Toy Poodle Pics and Videos

Just to share some pictures and videos of Charlie the toy poodle. Actually, we are unsure of whether he is a pure toy poodle or not, some people commented that he does not look like one! Charlie is 6 months old now.

Poodle apparently descended from a water dog in Germany. Charlie the poodle loves to play water! Also, poodle is commonly said to be the 2nd most intelligent breed, after Border Collie.

How to convert w/w% weight concentration to ppm

In this post, we describe how to convert w/w% (weight concentration of a solution) to ppm (parts per million, or mg/l), with applications to liquid fertilizers.

This method is an approximation for dilute solutions.

We will focus on converting 0.8 w/w% to ppm, with 2ml of fertilizer in a 5 gallon container. This is based on Tropica fertilizer Potassium concentration. We will then verify it with the Rotala Butterfly calculator (answer is 0.845 ppm).

1) 0.8 w/w% = 8g per 1000ml

Here we have made the assumption that 1000ml of solution weighs 1000mg, which is valid for dilute solutions.

2) This is equivalent to: 0.016g per 2ml (in the fertilizer).

3) Now after pouring the fertilizer into the 5 gallon container, the concentration is 16mg per 5 gal = 16mg per 18.9271 liters.

Here we have made the approximation that the amount of fertilizer (2ml) is negligible compared to the volume of the container (5 gal).

4) This is equivalent to 0.845 mg per l or 0.845 ppm as calculated by the Rotala Butterfly calculator!

Rotala Butterfly Calculator Formula

Let a be the w/w% concentration.

Let b be the amount of fertilizer to use (in ml).

Then,

ppm = (10ab)/18.9271

In the example above,

a=0.8, b=2, so

ppm = (16)/18.9271=0.845

Mango Sticky Rice

Recommended Mango Sticky Rice Recipe!

Cooking For Fun

Finally I made one of my favorite dessert: mango sticky rice.

Ingredients:

Sticky rice 1 cup

coconut milk 2/3 cup

sugar 1/3 cup

salt 1/2 tsp

1, Wash sticky rice in water till water is completely clear. Soak them overnight.

2, Drain them and steam over hot water for about 30 mins.

3, When the sticky rice is about to be done, start to make the sauce.

4, Add coconut milk, sugar and salt into a pot. Turn to low heat, keep stirring till sugar is dissolved.

5, Put sticky rice into a big bowl, pour the sauce in. Stir slightly to mix them. Then cover the bowl and let it rest for about 20 mins. Rice will absorb the coconut sauce and flavor.

Fot topping:

1/2 cup coconut milk

1/4 tsp salt

1 tsp rice flour

1 tbsp water.

Heat a pot, Add in coconut milk and salt. Stir…

View original post 35 more words

NUS High E-Open House

URL: https://www.nushigh.edu.sg/admissions/open-house

NUS High will be holding its E-Open House on 15th May. Do check it out!

NUS High is famous for its strong Math and Science curriculum. Many of their students are very strong in Math Olympiad and other Scientific topics.

E-Open House
15th May (Short Presentation and Q&A session with School Leaders, Alumni and Parents)

1st Session: 9:00 – 11:00 am
2nd Session: 2:00 – 4:00 pm

E-Engagement Sessions

1st Session: 19th May (Tue), 4:00 – 5:00 pm
2nd Session: 23rd May (Sat), 9:30 – 10:30 am
3rd Session: 23rd May (Sat), 2:30 – 3:30 pm
4th Session: 27th May (Wed), 4:00 – 5:00 pm

For further clarifications, please email: newton@highsch.nus.edu.sg

Also check out:

Update (provided by one of my Facebook readers):

NUS High School has put out its school presentation as part of its E-Open House on 15 May 2020, and its related e-engagement events for parents and interested P6 students. The content is well planned to clarify common questions from parents and potential students.

YouTube link to the school presentation (about 30mins long):

There is also a Telegram group to receive information on NUSH Admissions for DSA 2020 (for the Class of 2026) :-
(please subscribe for timely updates !) https://t.me/nushighschool

Nano Fish Species [35 fish/aquatic creatures below 9 cm!]

Fish	Max Length (cm)
Dwarf gourami	8.8
Black skirt tetra	7.5
Betta splendens	7
Honey gourami	7
Amano shrimp	6
Guppy (female)	6
Panda corydoras	5.5
Otocinclus	5.5
Cardinal tetra	5
Harlequin rasbora	5
Serpae tetra	5
Rummy-nose tetra	5
Zebra danio	5
Mexican dwarf crayfish	5
Cherry barb	5
Endler’s livebearer (female)	4.5
Cherry Shrimp (Neocaridina davidi)	4
White Cloud minnow	4
Sparkling gourami	4
Hara jerdoni	4
Neon tetra	3.5
Guppy (male)	3.5
Green neon tetra	3.5
Clown killi	3.5
Pea pufferfish	3.5
Assassin snail	3.5
Dwarf corydoras	3.5
Pygmy corydoras	3.2
Lambchop rasbora	3
Pseudomugil gertrudae	3
Horned Nerite Snail	2.5
Endler’s livebearer (male)	2.5
Celestial pearl danio	2.5
Chili rasbora	2
Phoenix rasbora	2

Credits: All images are from Wikipedia (and/or my personal collection of fish), unless otherwise specified.

Fish Math

How to ensure a pair of male-female for fish & Shrimp

Given N fishes/shrimp, what is the probabillity of having at least 1 male-female pair?

Probability = 1 – (Prob. Of all Male)- (Prob. Of all Female)

If you have 4 fishes, Probability of having a breeding pair = 87.50%

If you have 5 fishes, Probability of having a breeding pair = 93.75%

If you have 6 fishes, Probability of having a breeding pair = 96.88%

If you have 7 fishes, Probability of having a breeding pair = 98.44%

If you have 8 fishes, Probability of having a breeding pair = 99.22%

5 gallon simple aquascape

If you enjoy fish / dog videos, do subscribe to our channel on YouTube!

Canon PIXMA G5020 (G5070) Review

Canon Most Ink Efficient Printer

Just bought this printer (Canon PIXMA G5020, which is listed in Singapore as Canon PIXMA G5070). It is ideal for home use for students and working professionals.

Its advantages include:

Very efficient “ink tank” system. The ink refill system is by bottles of pure ink liquid instead of cartridges.
Design for high volume printing at low running cost
Compact size and dimensions (Approx. 403 x 369 x 166 mm for factory configuration, Approx. 403 x 695 x 356 mm when Output/ADF trays extended)
Dual paper loading (you can load paper on the rear tray as well as the front tray). If you retract the rear tray, the printer becomes even more compact (just 16.6cm tall).
High speed (for inkjet): ISO standard print speed (A4): up to 13.0ipm black / 6.8 ipm colour
Supports wireless connection to computer as well as smart phone.
Automatic Duplex

Canon PIXMA G5020 Wireless MegaTank Single Function SuperTank Printer | Mobile & Auto 2-Sided Printing

Overall, this is the ideal printer for work from home, as well as homeschool purposes. It is even more ideal for those who don’t want additional features such as scanner and fax. By not having those features (which you may not need), it has a very economical affordable cost. Especially when you factor in the long term savings from cheap and long-lasting ink refills.

If you do want copier, fax and scanning features, then you can consider the Canon PIXMA G7020 instead, which is basically the Canon G5020 with the additional features.

Canon PIXMA G7020 Wireless All-in-One Supertank (Megatank) Printer, Copier, Scan, Fax and ADF with Mobile Printing, Black

How to speed up R code in RStudio

I just found out by trial and error that the suppressing of print statements in RStudio greatly speeds up the R code.

In my case, code that was originally estimated to take around 40 hours to run, just ran in under an hour after I suppressed all the print statements in the for loops.

This is supported by evidence in other forums, for example in StackOverflow: R: Does the use of the print function inside a for loop slow down R?

Basically, if your code prints too much output to the console, it will slow down RStudio and your R code as well. It may be due to all the output clogging up the memory in RStudio. R is known to be “single thread” so it can only use 1 CPU at a time, even if your computer has multiple cores.

Hence, the tips are to:

Reduce the number of print statements in the code manually.
Set quiet=TRUE in all scan statements. Basically, the default behavior is that scan() will print a line, saying how many items have been read.

This is especially true with for loops, since the amount of printed output can easily number to the millions, and overwhelm RStudio.

5 Tips on How to Survive Physics in Junior College

5 Tips on How to Survive Physics in Junior College

Many students, during the early stage of their college life, tend to struggle through an entirely new syllabus for physics. Apart from the complexity of the discipline, the problem with physics gets more aggregated when different new teachers teach it, each having their teaching methods. Surviving the ‘torments’ of physics in junior college, especially in an as a highly-ranked country like Singapore, isn’t that easy. However, it’s not impossible, either!

You don’t have to spend any more extra time or money to get into a popular physics tuition center in Singapore. Instead, you can prepare yourself with these five life-saving tips to help you survive the two-year roller coaster ride!

A good relationship with your instructors

You need to enhance your bonding skills and treat your physics teachers more as life mentors at this point. The more you value their presence in your life, and maintain a helpful, friendly relationship with them, the better are your chances of you getting their additional assistance like extra classes. This will make it easy for you to understand the problematic theories and get more attention in the class.

The priority is understanding!

The transition from secondary school to junior college is indeed one of the most significant phases students in Singapore academically go through. No wonder why the syllabus for physics looks so exhausting, right? Even if you get poor marks at the beginning, make sure you understand the theoretical maths and laws. Frequently ask questions and request further clarification in the class until you have understood correctly.

A clear understanding is what matters the most! Furthermore, pay more attention to your progress in the maths classes as wells! Physics and maths are closely related to each other so that you will benefit either way. Consider enrolling in a popular maths tuition center in Singapore, if you think you need extra help.

Sign up for physics courses

While your everyday studies will most of your time, try your best to focus on something else outside the monotonous realm of academics. Make sure you are a lead member of your science or maths club. Extra-curricular activities on physics will come in handy for you to achieve better grades. If you can afford more time, try to enroll in online physics courses on educational platforms. You can also watch physics tutorials online to clear any subtle confusions on the basics.

Seek help from your seniors

No doubt that in junior college, all the students naturally go through a hard time. However, that is not enough to justify that your seniors will have no time at all to lend forward their help to those who are still new to junior college! Therefore, maintain a friendly relationship with all your seniors who are seemingly performing great in physics and maths. Shower them with respect, let them know how they inspire you. They will definitely try to make out some time to help you out!

Get a private tutor!

Additional tuition, especially that too of an as complicated a subject as physics, is instrumental in junior college. Most tutors are high-qualified and are naturally aware that you’re still adjusting to the advanced level of theoretical physics, and they can help make the transition easier for you. Moreover, this can also be a perfect time to productively utilize any leisure available, which is something that most tuition centers or private tutors will focus on teaching you first.

We do understand, junior college physics is very tough, but it’s possible to pull through, especially by following the tips provided above. If you can sincerely abide by them and along with that, just a pinch of persistent merit with two spoons of will and hard work will be enough to score good grades in your physics exams!

StarHub Rebate Registration Form

StarHub Rebate Link

In addition to the apology, StarHub will offer affected customers a one-time 20% rebate on their Home Broadband monthly fee, which is equivalent to six days of free home WiFi service. A dedicated website will be made available for affected customers to register for the rebate. Details will be announced to customers soon.

Note that the deadline is: 26 April 2020!

Share this to your friends and relatives using StarHub! This rebate is typically worth around $10 (20% of $50 broadband subscription). The key thing is that only those who registered above will be given the rebate!

Amount of Potassium in Singapore Water

The official document for Drinking Water Quality analysis can be found on the PUB website.

Note that the above document does not contain any information on potassium (K).

Potassium Content in Singapore tap water

I managed to find another source (dated 2002) on potassium content in NEWater: http://uwatech.com/wp-content/uploads/2015/11/newater-study-report.pdf. In page 16, the potassium levels are stated as:

Range (Potassium): 0.504 to 3.07 mg/L

Mean (Potassium): 1.08 mg/L

Sodium Content in Singapore water

Range (Sodium): 3.16 to 42.1 mg/L

Mean (Sodium): 13.35 mg/L

Potassium in Planted Tanks

For aquarium plants, “potassium content should be at least equal to sodium content or higher.” (http://aquayer.com/index.php?page=kaliy-v-akvariume&lang=en)

Usually, the solution is to dose potassium fertilizers (for example potassium sulphate).

Seachem Flourish Potassium 500ml

In addition, many sources recommend a level of around 20 ppm of Potassium for planted tanks (see for instance this site). That is 20 times the amount found in tap water! Other sources push it further, there are sites that recommend up to 50 ppm of potassium.

Tropica fertilizer composition

Tropica has 2 brands of liquid fertilizer — Specialised Fertilizer and Premium Fertilizer.

The Specialized fertilizer has N+P (nitrogen and phosphates), while the Premium does not. Unfortunately, not much information is available on the exact ingredients, composition, or percentage of each type of nutrient. For example, it is unclear how much potassium the fertilizers have.

I managed to find the exact composition on the UKAPS forum:

Tropica Fertilizer Composition and Ingredients

Nutrient (w/w%)	Premium Fertilizer	Specialised Fertilizer
Nitrogen	0	1.34
Phosphorus	0	0.1
Potassium	0.8	1.03
Magnesium	0.39	0.39
Sulfur	0.91	0.91
Zinc	0.002	0.002
Molybdenum	0.002	0.002
Boron	0.004	0.004
Iron	0.069	0.069
Copper	0.006	0.006
Fluoride	<0.001	<0.001
Chlorine	0.438	0.5
Manganese	0.039	0.039

The Declaration Certificate showing composition of Tropica fertilizers.

Tropica Specialised Fertiliser – 300 ml

Tropica Plant Growth Premium Fertiliser,300 ml

Tropica Fertilizer ppm

The composition of ingredients given by Tropica is in w/w% which is weight concentration of a solution. Usually, we want to know the concentration in ppm, or parts per million (equivalently, mg/L).

For that, we can use the Rotala Butterfly calculator. The below information is based on 1 pump (2ml) for a 5 Gallon aquarium.

Your addition of 2 ml (equivalent to 1/4 tsp + 1/8 tsp + 1/32 tsp ) Tropica Plant Growth Premium to your 5gal aquarium adds:

Element	ppm/degree
K	0.845
Mg	0.412
S	0.962
Fe	0.073
Mn	0.041
B	0.004
Cu	0.006
Mo	0.002
Zn	0.002
Cl	0.463

It is quite a “light” dose. Considering that the recommended target concentration of K is 10-30 ppm (from Tom Barr). Singapore water only has on average 1 ppm for K (potassium). Hence, the once a week dose of Tropica fertilizer Premium is definitely not enough to hit 10-30 ppm of K.

StarHub Down

Is StarHub down?

The answer is yes! Please see the official news by Today: StarHub customers hit by major fibre service disruption.

It is also reported by Straits Times that, yes, StarHub is down.

StarHub Network Down (Solved)

I stumbled upon the solution to solve the issue of “Starhub Network Down”. Note: This applies if your Starhub Network is slowed down but not completely dead/inaccessible.

Solution: Google DNS

My StarHub internet slowed down to a crawl, it took almost forever to access a simple website like Gmail or Yahoo. Hence, it can be classified as “StarHub Almost Completely Down“.

Upon changing to Google DNS using this official Google guide, to my astonishment the internet sped up to be even faster than before the “StarHub Down” issue.

Speed test of StarHub internet speed (after changing to Google DNS) on the day that StarHub was supposedly down!

I am not exactly sure of the mechanism behind, but changing to Google DNS certainly solved the issue of “StarHub Internet Down” for me. I suspect that due to the StarHub network down issue, most of StarHub remaining working “servers” are overcrowded and overloaded. Hence, if you switch from the StarHub DNS to Google DNS, you are leaving the “crowded server” and that explains the faster speed.

For record, I used the following Google DNS (IPv6):

2001:4860:4860::8888 and 2001:4860:4860::8844.

For safety concerns, it is considered quite safe to trust Google DNS. (Read their details on Wikipedia.) Basically, if you are already using Google products like Gmail, Google search engine, you might as well use Google DNS.

PerroMart Discount Code

PerroMart SG is an online pet store in Singapore specializing in dog and cat food and products. It has an extremely wide range of food/products at very reasonable prices. During this COVID-19 period, it has free delivery!

For example, it has Himalayan Yak chew for dogs, which is a very rare dog chew that lasts very long and is very suitable for dogs. It also has exotic Kangaroo meat treats which are also very healthy for dogs. PerroMart also has overseas brands of dog food like the famous “Taste Of The Wild”.

PerroMart Discount Coupon

5% off coupon: PerroMart 5% Discount Coupon

Click on the above link to get a valuable 5% off coupon!

PerroMart Discount Codes

Use “PERROMART5” for $5 discount!

(The above code is valid as of April 2020.)

Absolute Bites Himalayan Yak Dental Sticks Dog Treats from PerroMart

100% Natural Himalayan Yak Chew comes from the ancient recipe of the people of Himalayas in Nepal.

KEY FEATURES

100% Grain Free & Gluten Free Dog Chew
No Artificial Ingredient
Ultra Durable & Long Lasting
High in Protein & Minerals, Rich in Calcium
Ideal for Teething Dogs

In the surrounding Mt. Everest at more than 15,000 feet, these dog treats are made using traditional methods with yak and/or cow milk, and all natural products with no preservatives, binding agents. These yak chews are gluten free, and also provide health benefits like protein, minerals and calcium. An excellent and unique dog chew for all breeds and sizes.

Himalayan Yak chew is made from the milk of the Himalayan yak. Yaks can weigh up to 1,200 pounds (550 kg).

PR Solidarity Budget Application

Just to share this information with readers who may be Singapore PRs.

PR $300 for COVID-19 (with Singaporean spouse/children/parent)

Official source: Straits Times

Eligibility:

Adult PRs with Singaporean parents(s), spouse or child(ren) are eligible
Must be living in Singapore

Key date: 10 May (Sun)

Eligible PRs can apply with bank account details by 10 May at go.gov.sg/sppr. Payment will be made on 19 May (Tue).

Key date: From end-May

LTVP+ holders will receive payment by cheque via post. No action needed.

PRs who apply without bank account details will receive the payment by mailed cheque from end-May.

LTVP+ holders aged 21 and above, who are foreign spouses of Singaporeans, can receive the payout as well.
Eligible permanent residents may sign up for the one-off payout at https://go.gov.sg/sppr using their SingPass from now until May 10.

Disclaimer: The above information is correct as of 12 April 2020. Please double check with the official source on Straits Times for the official latest information: https://www.straitstimes.com/singapore/coronavirus-9-in-10-singaporeans-to-receive-600-each-on-april-14

Food for Chili Rasbora

How to feed Chili Rasbora / Phoenix Rasbora in Community Tank

Chili Rasbora / Phoenix Rasbora and other small Rasboras like dwarf Rasboras have the following characteristics:

Very small mouths
Quite shy
They are micropredators (require “animal” / high protein food)

How I feed them is actually to take Betta food (Hikari Betta Biogold), and crush them with a mortar and pestle. Betta is also a predator hence their dietary requirements are kind of the same (high protein rather than high vegetable content). Then, together with the Neon Tetra pellets, pour it into the tank. There is bound to be food stuck to the container, which we use tank water to soak it and pour it out.

Repeat until all food is dispensed. Due to the numerous powder food in the water, the Neon Tetras are unable to snatch all the food, and the small Rasboras (Boraras Merah) are able to sneak in a few bites. At the end, all Rasboras are well fed as shown by their round bellies.

If the food is not crushed to powder, the Rasboras would not be able to swallow the food easily, and the end result is that most of the food is eaten by the Tetras. It took me quite a few months to figure the above procedure out (I was and still am quite new to fish keeping).

Hikari Betta Bio-Gold Baby Pellets Fish Food Bundle Bonus Pack 3 Pack

AI can’t predict how a child’s life will turn out even with a ton of data

Despite the great hype of AI, there are still many limitations of what AI can do. Real life is too complicated for a machine to figure out, at least currently.

Source: MIT Tech Review

Hundreds of researchers attempted to predict children’s and families’ outcomes, using 15 years of data. None were able to do so with meaningful accuracy.

Now a new study published in the Proceedings of the National Academy of Sciences casts doubt on how effective this approach really is. Three sociologists at Princeton University asked hundreds of researchers to predict six life outcomes for children, parents, and households using nearly 13,000 data points on over 4,000 families. None of the researchers got even close to a reasonable level of accuracy, regardless of whether they used simple statistics or cutting-edge machine learning.

“The study really highlights this idea that at the end of the day, machine-learning tools are not magic,” says Alice Xiang, the head of fairness and accountability research at the nonprofit Partnership on AI.

Install Windows on MacBook (Fast and Easy method)

Basically, you just need to follow the instructions in the YouTube video below. It is very easy and fast. The key software is VirtualBox.

You can download the official Windows 10 ISO disc image here: https://www.microsoft.com/en-gb/software-download/windows10ISO

Note that Windows 10 (Home) is free (you don’t have to activate it) and you can use it with only very minor restrictions.

Overall, the process to install Windows 10 on a Mac (using VirtualBox) is much easier than I expected.

Total time taken: Around 30-40 minutes (possibly faster if your download speed and RAM is fast)

Total cost: $0

Total space needed: Around 10-20 GB is needed initially. VirtualBox allows “dynamically allocated disks” which are faster to create and can grow to larger sizes. For example, if you set 50GB as your disk space (but only use 10 GB) then it will only occupy 10 GB on your Mac.

Aquatic Plants 水生植物

An introduction to the aquatic plants in my low tech tank:

1) AR Mini 迷你血心兰

2) Java Fern 铁皇冠

3) Dwarf Sag 矮慈姑

4) Cryptocoryne Wendtii 绿温蒂椒草

5) Giant Salvinia 槐叶萍

6) Anubias 水榕

7) Marimo Moss Ball 海藻球

How to keep Python / R Running on Mac (without screen lock or sleep)

When the Mac (or MacBook) is running for a long time, it is very liable to do one of the following things:

sleep
screen saver
lock screen

The problem is that your Python program or R program running in the background will most likely stop completely. Sure, it can resume when you activate the Mac again, but that is not what most people want! For one, it may impact the accurate calculation of elapsed time of your Python code.

Changing settings via System Preferences -> Energy Saver is a possible solution, but it is troublesome and problematic:

Have to switch it on and off again when not in use (many steps).
Preventing sleep may still run into screen saver, screen lock, etc.
Vice versa, preventing screen lock may still run into Mac sleeping, etc.

The solution is to install this free App called Amphetamine. Despite its “drug” name, it is a totally legitimate program that has high reviews everywhere. What this app does is to prevent your Mac from stopping, locking or sleeping. Hence, whatever program you are running will not halt till the program is done (or when you switch off Amphetamine).

It is a great program that does its job well! Highly recommended for anyone doing programming, video editing or downloading large files on Mac.

Best way to time algorithms in Python

There are tons of ways to calculate elapsed time (in seconds) for Python code. But which is the best way?

So far, I find that the “timeit” method seems to give good results, and is easy to implement. Source: https://stackoverflow.com/questions/7370801/measure-time-elapsed-in-python

Use timeit.default_timer instead of timeit.timeit. The former provides the best clock available on your platform and version of Python automatically:
from timeit import default_timer as timer

start = timer()
# ...
end = timer()
print(end - start) # Time in seconds, e.g. 5.38091952400282
This is the answer by the user “jfs” on Stack Overflow.

Benefits of the above method include:

Using timeit will produce far more accurate results since it will automatically account for things like garbage collection and OS differences (comment by user “lkgarrison”)

Please comment below if you know other ways of measuring elapsed time on Python!

Other methods include:

time.clock() (Deprecated as of Python 3.3)
time.time() (Is this a good method?)
time.perf_counter() for system-wide timing,
or time.process_time() for process-wide timing

Buy Prescription Glasses, Spectacles & Sunglasses Online from the UK’s Favourite Online Optician!

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All purchases are backed up by our 30 day ‘No Risk – No Quibble’ money back guarantee.

Worry Doesn’t Solve Anything

Source: Pastor Rick Warren

BY RICK WARREN — MARCH 31, 2020

“Do not worry about your life, what you will eat or drink; or about your body, what you will wear. Is not life more than food, and the body more than clothes?”

Matthew 6:25 (NIV)

Worry is essentially a control issue. It’s trying to control the uncontrollable. We can’t control the economy, so we worry about the economy. We can’t control our children, so we worry about our children. We can’t control the future, so we worry about the future.But worry never solves anything! It’s stewing without doing.

Jesus actually gives four reasons you don’t need to worry in his Sermon on the Mount.

1. Worry is unreasonable.
Matthew 6:25 says, “Do not worry about your life, what you will eat or drink; or about your body, what you will wear. Is not life more than food, and the body more than clothes?” (NIV).

Jesus is saying, if it’s not going to last, don’t worry about it. To worry about something you can change is foolish. To worry about something you can’t change is useless. Either way, it’s unreasonable to worry.

2. Worry is unnatural.
Jesus gives us an illustration from nature in Matthew 6:26: “Look at the birds of the air; they do not sow or reap or store away in barns, and yet your heavenly Father feeds them. Are you not much more valuable than they?” (NIV).

There’s only one thing in all of God’s creation that worries: human beings. We’re the only things God has created that don’t trust him, and God says this is unnatural.

3. Worry is unhelpful.
It doesn’t change anything. Matthew 6:27 says, “Can any one of you by worrying add a single hour to your life?” (NIV). When you worry about a problem, it doesn’t bring you one inch closer to the solution. It’s like sitting in a rocking chair—a lot of activity, energy, and motion, but no progress. Worry doesn’t change anything except you. It makes you miserable!

4. Worry is unnecessary.
Matthew 6:30 says, “If that is how God clothes the grass of the field, which is here today and tomorrow is thrown into the fire, will he not much more clothe you—you of little faith?” (NIV). If you trust in God, you don’t need to worry. Why? Because he has promised to take care of all your needs: “God will meet all your needs according to the riches of his glory in Christ Jesus” (Philippians 4:19 NIV).

That includes your bills, relational conflicts, dreams, goals, ambitions, and health issues you don’t know what to do with. God will meet all your needs in Christ.

Don’t worry about it!

Seachem Root Tabs Review

Just added 1 Seachem Flourish Tab next to my Alternanthera Reineckii Mini (AR Mini). Some “fizzing” or bubbling is observed. Not sure if that is due to the root tab, or maybe I disturbed some gas pockets in the substrate.

I am still continuing the growing of AR Mini in low tech tank (see Alternanthera Reineckii Mini Low Tech).

Seachem Flourish Tabs Growth Supplement – Aquatic Plant Stimulant 10 ct

My dog Charlie curious about the Seachem Root Tab.

Seachem Root Tab Review

The below review video is rather convincing proof that Seachem Flourish tabs are one of the best root tabs in the market, despite having low macro nutrients (nitrogen and phosphate). The purpose of having low macro nutrients is for preventing algae.

Singapore PM Lee Hsien Loong Mentions Tropical Fish Shop in his speech on COVID-19

PM Lee Hsien Loong on the COVID-19 pandemic: “I am in this for a very long time to come. To sustain this, I need everybody’s cooperation – safe distancing, personal hygiene, cooperation when we are contact tracing and discipline when people come back, stay home notification, stay home.” (Video: PMO)

Something interesting in this speech is that PM Lee mentions the plight of a tropical fish shop owner in Singapore.

Time around 5.22:

PM Lee chats with a Tropical Fish shop owner in Teck Ghee, who has been there for “donkey’s years”. She says her supplies come from Malaysia, and Malaysia has locked down. Tropical fish is not an essential item, how does she get her business going?

Underwater Garden

Very low tech 5 gallon tank for my Phoenix Rasboras (Boraras Merah) and Neon Tetras. I just let the plants grow naturally without CO2, with occasional trimmings. If you look carefully, you can see the Horned Nerite Snail eggs (they look like sesame seeds)!

Home Cooked Food for My Dog Charlie

Cooking For Fun

My husband and I got this poodle Charlie last month. Ever since this little cutie came to our house, our life completely changed.

I feel so lucky to have such a little playful buddy as our family member.

Most time, Charlie has dog food which was bought from pet store. But sometimes, especially on some big occasion, I will cook for him.

Actually, cooking for dog is much easier than cooking for human, as there is no need to season or to make different flavor. Home cooked dog food has a very simple rule – boil.

Ingredients I use are always chicken breast, potato and carrot. Charlie is only 3 kg now. He was 1.5 kg when he first came. So Charlie has very little appetite. He can’t eat too much.

The very simple way to deal with ingredients is to chop everything into small dices. You can choose 1…

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Buy surgical mask online Singapore

Just bought this Dotafa (4-ply surgical mask made in Vietnam) mask from Qoo10.

The quality is good, with good thickness (see picture below). Delivery speed is fast as well (just 2 days using Qprime delivery). Only issue is the expensive price (around S$1 per mask), but that is the market rate nowadays…

The consensus is that made in Vietnam & made in Indonesia (3-ply or 4-ply) are the best options to get nowadays. This current batch may be the last batch since the respective countries are cracking down on the export of masks.

[S$28.90](▼52%)SG LOCAL STOCK SURGICAL FACE MASK MASKS 3PLY HAND SANITISER

WWW.QOO10.SG

Photo of the “Dotafa” surgical mask (4-ply). There are other equivalent Vietnamese manufacturers as well on Qoo10.

Where to buy surgical mask in Singapore

This is an update to the earlier post: Where to buy surgical mask Singapore.

Summary:

Basically, surgical masks are totally sold out in pharmacies like Watsons, Guardian, Unity, etc. Hand sanitizers are still in stock though, if you are interested to buy.
Korean masks on Qoo10 are mostly out of stock.
Currently, Qoo10 carries mainly Indonesian and Vietnam surgical masks, market price is around S$50 per box of 50 masks, i.e. around S$1 per mask.

The below Qoo10 shop (local stock) carries masks made in Indonesia and Vietnam masks (3 ply), with certificates. Basically, according to the reviews, the masks are genuine, only issue is that it is quite pricey. Apparently, the high price is set by the mask manufacturers and suppliers, it is not entirely the fault of the Qoo10 sellers that the price is so high. (Basic economics: High demand + low supply = High price.)

[S$26.90](▼56%)SG LOCAL STOCK SURGICAL FACE MASK MASKS 3PLY HAND SANITISER

WWW.QOO10.SG

Example of certificate for made-in-Indonesia mask:

[S$29.90](▼58%)⏰⚡ [SG Ready Stock 16 MAR] Surgical Mask 3ply ★ OneMed Sensi Masks ★ Ship within SG n to Overseas

WWW.QOO10.SG

According to the above Qoo10 seller, the current batches would be the last batches as Indonesia has crackdown on export of surgical mask. Vietnam has also banned export.

Shrimp Videos

I find that shrimp are just as interesting as fish to keep in an aquarium. Shrimp are very good at tidying/cleaning up the aquarium; it is a great idea to keep some shrimp whenever possible.

The easiest shrimp to keep are cherry shrimp (and its color variants), and also the Amano shrimp. The biggest cause of shrimp deaths is due to molting problems. Below are some videos of the shrimp I have personally kept.

Easy to keep shrimp: Amano shrimp, cherry shrimp (Neocaridina davidi).

More difficult shrimp: Bamboo shrimp (aka Wood shrimp), Bee shrimp (I have not tried these yet), Sulawesi Shrimp (not tried yet either).

AR Mini Low Tech Day 50

Day 50 (12 March 2020): The aquarium light was upgraded around 10 days ago on 2 March 2020. It has helped the AR Mini in my opinion, making it slightly redder. The AR Mini is very much alive in the low tech tank! I think this dispels the myth that Alternanthera Reineckii Mini requires CO2 to live.

Ryo Watanabe Fish

In this video, popular fish YouTuber Ryo Watanabe is featuring the famous Clementi 328 (C328) Fish Store, arguably the best aquarium in the west (along with its neighboring shops in the stretch of Clementi Block 328).

Clementi Block 328 is my favorite fish store. Chances are very high that you can find whatever you are looking for in one of the shops in the stretch. Other than C328, other notable shops in the area include Polyart, and That Aquarium, and more.

Each store there has its own characteristics, they are unique in their own way (the fish/plants/equipment they carry are all different, it is clear they have different suppliers):

Polyart Clementi: Large collection of fish, including some saltwater. They do carry plants. Their equipment collection is very extensive, and notably they are cheaper than other Polyart outlets (the uncle will often give you a discount off the stated price without you even asking). I usually buy equipment/medication/anti-chlorine from this store.

That Aquarium: Features some of the more exotic fish (I once saw freshwater seahorses, aka pipefish) and shrimp (some black King Kong shrimp or similar that costs up to $100 per shrimp). They do have collection of a lot of “high class” food and equipment that may not be found in other shops.

C328 Aquarium (featured in Ryo Watanabe Fish Video): This store is crammed full of fish, plants and equipment. Notably, the plant section is more extensive than other shops in the Clementi 328 stretch, including frequent sightings of Bucephalandra and other rarer plants. Most of my plants are bought here.

LFS Aquarium: This store is the first fish store on the left. I have good experience buying their fish, so far their fish tend to be healthy without disease. They have good collection of nano fish, which I am interested in. For example, mosquito rasbora, lambchop rasbora are often spotted in their store. They also have Betta in their community tanks, which means that those Betta are proven to be less aggressive and can live with other fish.

Ryo Watanabe Fish Video

Ryo Watanabe also does Fish Videos in Japan, where he is based at currently. Ryo Watanabe’s fish videos center on freshwater fish, including aquarium plants and aquascaping.

Chai Discus Shop Tour by Ryo Watanabe

Pinterest Update

Previously, I tried using the automatic Pinterest RSS Feed but to no success. I even tried posting on the WordPress.com forum but again it did not address the problem. (To be fair, this is probably a problem on the Pinterest side.) Hence, the conclusion is that currently the WordPress.com to Pinterest automatic posting does not seem to work. (It apparently works for WordPress.org users according to my search on Google.)

Thus, I have manually added some pictures from Mathtuition88 (including reblogged content) onto Pinterest. Feel free to share it!

Manually adding pictures onto Pinterest is quite tedious and time-consuming. I will be monitoring how much effect Pinterest has, in terms of channelling traffic.

Free COVID-19 Insurance (DBS/POSB customers)

I looked through this free insurance by DBS, there seems to be no “catch” to it, i.e. it is really a 100% free insurance for you.

Maybe only “downside” is that you will have to provide your contact information which can be used by DBS/Chubb to “contact you via email, SMS and phone calls in respect of promotional offers”.

URL: https://marketplace.dbs.com.sg/insure/personal/2019-nCoV/coverage/

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Daily Hospital Cash Benefit

Receive SGD 100 per day, up to 14 days in the event of hospitalisation due to COVID-19
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30 days of free coverage

Your cover starts immediately once you submit your application, and expires automatically at the end of 30 days

Anubias Rhizome tied too tight

Anubias tied too tightly

I think one of my Anubias rhizomes died (rotted) due to it being tied too tightly. The Anubias rhizome is supposed to be hard and green, if it is soft or brown, something is wrong.

For Anubias, the rhizome is the most important part of the plant, if it is dead, the whole plant will die.

Another reason for the Anubias rhizome rotting is the dreaded Anubias disease, but I don’t think it is the case here because another rhizome just next to the rotted rhizome is perfectly healthy.

Hence, the conclusion is that the Anubias rhizome most likely died from being tied too tightly by the string. It was at the back of my tank so I didn’t really notice it at first. I only noticed it when I saw a new leaf sprout out from the rotting rhizome, but the new leaf melted soon after. Usually, when new leaves melt, it is a sign of something wrong. Upon taking the entire Anubias plant out, I then realized that the rhizome had turned mushy.

The original Anubias was tied (by the seller) with thick string. I don’t really blame them for tying too tight because it is not easy at all to tie Anubias (too loose and it will not stay in place). I cut off the old string, threw away the rotted rhizome, and re-tied the healthy Anubias lightly with sewing thread.

Probably the same problem can occur for Java Fern, Bucephalandra, the rhizome may rot if tied too tightly.

Hikari Shrimp Cuisine Review

I find this Hikari Shrimp Cuisine quite good. The pellets are quite small sized so you can control exactly how much you want to feed (down to each individual pellet).

Hikari Inc AHK19404 Shrimp Cuisine 0.35 -Ounce

How to feed Hikari Shrimp Cuisine Pellet (without fish snatching it away)

This was something that perplexed me for a long time. My fish would grab any food meant for the shrimp, leaving close to nothing left for the slower moving shrimp.

The solution I found was to:

Put the Hikari Shrimp Cuisine pellets in a small container with tank water.
Crush the pellets (I just use my finger).
Stir to “dissolve” the pellets a little. Stirring also helps the pellets to sink.
Pour the water with “dissolved” pellets back into the tank.

You may switch the order of steps 1 & 2 if you like (I find it easier to crush the pellets when wet).

The main reason why this works is because:

Hikari Shrimp pellets are sinking (this is very important since shrimp can only eat sinking pellets that reach the floor).
By crushing the pellets into powder, it is virtually impossible for the fish to snatch all the shrimp’s food.
Some, if not most, of the powder will reach the tank floor, where the shrimp can find and eat it.

Another way to feed shrimp exclusively is the usage of a shrimp feeding tube and feeding dish.

JZMYXA Shrimp Feeding Tube and Feeding Dish, Fit for Shrimp Fish, Mini Size, High Transparent Acrylic Material

How much Hikari Shrimp Cuisine Pellets to feed

This depends on how many shrimp you have, and also your tank setup. Ideally, shrimp such as cherry shrimp or Amano shrimp can survive on algae and biofilm. Hence, if your tank is well planted, you only need to feed lightly. Personally, I only feed the shrimps once a week, at around 2 Hikari Shrimp pellets per shrimp.

If your tank is bare (no plants), you need to feed more, maybe once every day or once every two days.

Supplementing with Hikari Shrimp food is good because it contains essential minerals like copper (shrimp need small amounts of copper) and other minerals that can help shrimp molt.

Toy Poodle Male Temperament

Just adopted a toy poodle (male). It is supposedly the 2nd most intelligent dog (after the Border Collie).

I was quite surprised that it is quite a well-behaved small dog, that seldom barks. It is currently 3 months, and only weighs around 1.5 kg.

Male vs female toy poodle temperament

Apparently, for poodles, it can often be the males that are more affectionate and loving and the females that are more dominant and challenging of authority. (Source: https://poodlereport.com/male-vs-female-poodles-what-are-the-differences/)

Another poodle website source claims that “males tend to be more affectionate, playful, easier to house break and train, attentive and more demanding of attention. They adore their people and want to please. Most importantly if you have more than one person in your family, male dogs love everyone equally and share their affection with everyone. Female dogs tend to be a one person dog.”

Domain Authority 31

Mathtuition88 has reached Domain Authority 31 (Moz DA).

Thank you to all who have ever linked to mathtuition88.com!

IMO Coach : Drill vs Think Style

Math Online Tom Circle

The USA IMO coach Prof Loh is the son of 2 Singaporean Math Prof (dad) & JC Math teacher (mom).
He uses the Chinese “drill” style + American “think” style to beat China IMO Team last few years.

https://m.toutiaocdn.com/group/6764245433339347460/?app=news_article_lite&timestamp=1574935791&req_id=201911281809500100100542211C369EF1&group_id=6764245433339347460

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