The following are some of the most important topics for Integrated Programme (IP) Additional Mathematics. Also applicable for the usual ‘O’ level Additional Mathematics.
Notice that Secondary 3 topics are very important as well, for the final Promo or ‘O’ levels. This can be a major problem for students who only start to study seriously in Secondary 4 — it can be a tough job to catch up with the important Secondary 3 topics.
Secondary 3 topics
Binomial Theorem
Indices and Logarithms
Coordinate Geometry of Circles
Linear Law
Secondary 4 topics
Trigonometry: R formula and Graphs
Differentiation and its Applications
Integration and its applications (including area under the curve)
The following are some motivational quotes by Dr. APJ Abdul Kalam, former president of India. The source is from Pinterest. I have also translated some of the quotes into Chinese.
I believe the quotes make perfect sense! Hope you find it motivational and useful as well.
Love your job but don’t love your company, because you may not know when your company stops loving you.
热爱你的工作，但不要爱你的公司，因为你不知道公司何时停止爱你。
Work is a never-ending process. It can never be completed.
工作是一个永无止境的过程。 它永远无法完成。
Interest of a client is important, so is your family.
客户的利益很重要，您的家人也很重要。
If you fall in your life, neither your boss nor client will offer you a helping hand; your family and friends will.
如果你在生活上遇到挫折，老板和客户都不会给你帮助；您的家人和朋友会。
Life is not only about work, office and client. There is more to life. You need time to socialize, entertain, relax and exercise. Don’t let life be meaningless.
Ludwigia Super Red, also known as Ludwigia Palustris or Ludwigia sp. red (mini) is one of the easiest low tech (No CO2) red plants. Due to its small size, it is suitable for nano tanks (with trimming).
It is rated “easy” by Tropica. In comparison, most other red plants are rated “Medium” or “Advanced”.
I am trying out this low tech easy red plant without CO2. Future updates will be posted on this page as well.
Day 1 (May 22, 2020):
Ludwigia Super Red 1st day in low tech tank!
Day 2:
This is the second day of growing Ludwigia Palustris, also known as Ludwigia Super Red (sp. red mini). I think new growth has already appeared at the top of the stems! The new growth seems not so red though, maybe my light is not strong enough.
Day 4:
Currently, it is day 4 of growing it. I dose basic fertilizers like Tropica Premium, Seachem Potassium (weekly) and also Seachem Root Tabs (once every few months). I think the plant is adapting to the new environment, I did notice a bit of melting going on.
Day 8:
Still surviving on Day 8! The new leaves are quite cool, they are mixed red and green in coloration, with red mostly at the tips. I wonder if they will turn red completely eventually.
Day 13:
We continue with Day 13 of growing Ludwigia Palustris (aka Ludwigia Super Red) in low tech without CO2. Seems to be surviving! There is a bit of “fungus” problem after feeding Hikari frozen brine shrimp, hopefully it clears after the water change.
Stay tuned for future updates. If you have any experience on growing Ludwigia in low tech tanks, please comment below!
Xiaozhuang Wong, also known as Dennis Wong (an expert aquascaper), has demonstrated that Ludwigia sp. red is actually the same plant as Ludwigia mini super red. It is the same plant, except that it grows smaller adult forms under lean fertilization regimes. This is similar for many plants. The below image shows Ludwigia plant taken from same cutting, grown under 2 different tank nutrient regimes. (Source: Xiaozhuang Wong Facebook)
Experiment done by Xiaozhuang Wong. Image from his Facebook.
Deviated Septum refers to the condition where the nasal septum (the bone and cartilage that divide the nasal cavity of the nose in half) is slanted or tilted to one side. The symptoms are typically nasal congestion or stuffiness in one side of the nose. Mild deviated septum is actually very common, 80% of people have it. Moderate to severe deviated septum may lead to nasal problems.
Deviated septum can be typically diagnosed through an X-ray or by nasal endoscopy. Currently, the main treatment for deviated septum is septoplasty, which is a surgical procedure. Due to the surgery involved, quite many people with deviated septum are not keen to undergo the procedure unless it is really serious.
Deviated septum is not a major illness, but the symptoms (of nose congestion) can be very annoying, and also may lead to related problems like sinus infections.
In my personal experience, the deviated septum itself is not the main cause of nose blockage. After all, air molecules are tiny, no matter how narrow is the nose passage, definitely air can pass through it. It is the associated problems of nasal turbinate swelling, and also other nose tissue (such as polyps) swelling and blocking the nose passage that causes the main problem of nasal blockage.
I have compiled a list of natural treatments and remedies that I have personally tried and found to relieve the symptoms of deviated septum. Hope it helps, and if you have other tips, you are welcome to leave a comment below.
Medical Disclaimer: This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding deviated septum or other medical conditions.
1) Nose Unblocking Exercises
I have previously blogged about this on Amazing method to unblock stuffy nose. This should be the first method you try since it is totally free and does not require any special equipment.
Basically, pinch your nose and sway, until you are almost out of breath, then breath in through your nose. This has scientific basis, by allowing carbon dioxide to build up and naturally clear your nose by constricting the blood vessels in your nose.
Another method is Nasal Septum Mobilization invented by Dr Alan Mandell. It is quite a novel method, so far I have only seen it on his YouTube channel and not anywhere else. I think it may work for people with Deviated Septum as a natural remedy. Basically, the way it works is by moving the septum so as to create a “motion” to unblock the nose.
2) Nasal Sinus Rinse or Spray
Due to deviated septum, there is a high chance that mucus / dust particles can get “stuck” on the side of the nose that is narrower. Without help, it can be stuck there for a long time and lead to sinus infections, nose blockage, or allergic reactions.
One way to loosen the mucus and wash away the dirt particles is via Sinus Rinse. This is actually a modern version of Neti Pots, which is an ancient Indian Ayurvedic treatment. The classic brand for Sinus Rinse is NeilMed, which is very convenient with pre-packed saline salts for the sinus rinse. (Rinsing with pure water is not recommended as it will be painful. Adding saline salts will make the rinse more comfortable as it has the same osmotic pressure as the human body.)
A related method to sinus rinse is sinus spray. It is a low-volume method of spraying salt water into the nose. The advantages is that it is more convenient to perform (no need to be near water source or sink). The disadvantage is that it may not be as effective as the high-volume sinus rinse in terms of dislodging particles in the nose.
Vicks inhaler is a menthol-based scented stick, that has the effect of creating a “cooling” effect in the nose, hence immediately creating a sensation of the nose being unblocked. It also has mild decongesting properties. I find that it does reduce the symptoms of nose block due to deviated septum.
The above 3 methods are considered non-medical in nature. Basically, safe to try as long as you follow the instructions in the labels.
4) Decongestants / Anti-histamines
When the nasal blockage is serious, one may try decongestants, which can typically be found in pharmacies without a doctor’s prescription. An example is pseudoephedrine, which can be found in medications like Robitussin, or Clarityn-D.
Anti-histamines can also help to reduce nasal turbinate swelling due to allergy. (Nasal turbinate swelling, also known as nasal turbinate hypertrophy, makes deviated septum worse by making the already narrow nasal passage even more congested.) Clarityn-D also contains the anti-histamine loratadine.
Not Recommended
It is usually not recommended to use Afrin nasal sprays or similar products. It is well known that it can lead to “rebound effect”, meaning that your problem becomes worse when stopping the spray.
The above are just personal natural remedies that I have tried, and found effective in combating deviated septum symptoms. Hope it helps!
I am a huge fan of simple, minimalistic Powerpoint templates with white background.
Why white background: Basically it is more convenient for printing (save ink), as well as it looks more elegant and professional.
However, most Powerpoint templates are too “flashy” or “colorful”.
On the other hand, the most basic template (just pure white background) is too dull and boring.
Simple Elegant Powerpoint templates
Actually the official Microsoft website has quite a few nice templates. The problem is that less than 5% of them satisfy the criteria of being simple, elegant, and white background.
I recall that this was very big news around 10 years ago. Basically, the author Dr. Cai Mingjie was a research scientist with a PhD from Stanford, specializing in Life Sciences (biochemistry and cell biology). However, he was fired/retrenched at the height of his career, for reasons that were largely unknown. He did not manage to find a job initially and became a taxi driver in November 2008, which he persisted for around six months. (He managed to find another job, though non-academic, subsequently.)
He started a blog called “A Singapore Taxi Driver’s Diary” (now deactivated), which became hugely popular. Subsequently, he published his blog as a book which is featured below.
For a free preview of his stories, one can actually click on the Amazon book preview to read a couple of the short stories. The stories are quite insightful, and motivational in a way. Taxi drivers have a unique perspective since they are able to observe all strata of society on a daily basis.
The free preview on Amazon has the following stories:
Day One (first day of working as taxi driver)
Broken Barrier and Two Unforgettable Customers
Preface & Epilogue (which describes the interesting background of the author)
Overall, the author deserves deep respect for being 能屈能伸, being able to take temporary setbacks; able to bow and rise at will. After all, being a taxi driver is a honest job.
I think the above book and news represented the start of the “bursting of the bubble” of Life Sciences, at least in Singapore. (If a life science researcher with Stanford PhD has problem finding jobs, how about those with lesser qualifications?) For those who recall, life sciences was hugely popular as a major around 10-20 years ago (2000-2010). Many JC students, including many of my classmates/acquaintances would choose it as their major in University. The life sciences department was one of the largest compared to other sciences like Physics or Chemistry. It turned out that the job opportunities in Life Sciences was not that plenty, and many would end up in careers totally unrelated to Life Sciences / biology.
iMovie is a great free movie editor for Mac. However, an annoying bug is that when two video clips are put together, there can often be “corrupted” frames, glitch, or even choppy video between the two clips.
Simple solution to iMovie Transition Glitch
There are some complicated solutions online, such as re-importing the video clips in certain formats.
However, a simple solution that I tried and tested to work in most cases is to try trimming off a few seconds from the start of the affected video clip. Or even adding a transition effect where the problem arises may work.
To explain more precisely, suppose the problem arises in between A -> B, where A and B are video clips. Then, you can try trimming off a few seconds off the start of video clip B, or adding a transition effect between A and B. (If there is already a transition from A -> B, try removing it!)
Another solution to iMovie Transition Bug
Another solution that I tried and works in some cases, is to export the movie via File -> Share in Best (ProRes) Quality, with Better Quality Compress.
Best (ProRes) Quality and Better Quality Compression may solve your iMovie glitching bugs.
Other solutions to iMovie Bugs between Video transitions
If you have other solutions that you have seen or tried out, please share it in the comments below!
Recently upgraded my air pump to the Eheim Air Pump 200, with dual output. My previous air pump was not strong enough to power 2 sponge filters simultaneously.
This Eheim Air Pump is very strong. In fact, it is almost too strong, I had to lower to the lowest setting for my 2 gallon nano tank. For the 5 gallon tank, I select the medium setting, and angle the output towards the wall. The sponge filter output was made to be above the water level (there is less turbulence this way).
Overall, this air pump is very good and quiet. Do expect some noise though, it is not totally silent. I would say it has the same noise level as a fan, which is totally acceptable. Also, I find that the 2 adjustable valves are not totally independent, when I adjust one valve it will affect the other output as well.
Review: The Eheim Air Pump is a highly recommended air pump for fish keepers with 2 aquariums.
The Eheim 200 Air Pump is also labelled as Eheim PHL207184. There is a more powerful Eheim 400 (twice the output), but based on my review most aquariums under 50 gallons should not require such a powerful pump (maybe 50 gallons and above may need it).
There are indeed more stray dogs than you imagine in Singapore. With the Trap-Neuter-Release-Manage (TNRM) Programme, we aim to reduce the number of strays out there over time. SOSD works closely with stray feeders in different parts of Singapore, in order to trap the dogs, especially the feral ones. Very often, these dogs have learnt to trust their feeders, and catching them would only be possible with the help and cooperation of the feeders who feed them daily.
Amidst the fight against COVID-19, we hope to extend a helping hand to our thankless stray feeders. 365 days a year, the stray feeders painstakingly prepare the daily meals for the stray doggies that they feed, before making their rounds around industrial areas, construction sites or forested areas to deliver food straight to the doggies’ bellies.
If you’ve been wondering how you can chip in during this difficult period, why not make a contribution to ease the pockets of the feeders?
For $98, you can purchase 1 large bag of dog kibbles, to feed 1 stray dog for 40 days.
Simply place your order below, and make payment via PayPal. Orders will close at 2359hrs on 31 May 2020, Sunday. When the donation drive ends, SOSD will coordinate the collection directly with the stray feeders at our supplier’s warehouse.
The WordPress Twenty Ten Theme was my favorite for a long time. However, it is now retired, meaning that it is no longer updated or supported by WordPress. Hence, it is recommended to switch to a newer theme.
WordPress Theme similar to Twenty Ten
I find that the Twenty Sixteen theme is quite similar to Twenty Ten in terms of layout. It has the signature top header as well as right sidebar classic layout. After much consideration and testing out other themes, I decided to switch to the Twenty Sixteen theme!
It does take some time to get used to the theme. The theme has a very clean and minimalistic look. In fact, the only downside I would say is that the 2016 WordPress theme is a bit too minimalistic, there is not enough colors other than white.
Recently, there is a sad news in Singapore about the euthanasia of a perfectly healthy dog called Loki, for purported “aggression”.
To read more, just google the following keywords:
loki dog
loki dog singapore
loki dog euthanasia
loki dog put to sleep
#justiceforloki hashtag on Twitter
You can also find more information on the Exclusively Mongrels Limited Facebook page. Exclusively Mongrels was the organization that Loki came from (Loki was a stray dog). One of the volunteers at Exclusively Mongrels was brave to speak out about Loki’s euthanasia, but unfortunately he is now being accused by the owners for “doxxing”.
Just to reblog this post on where to find “A Level Free Exam Papers”. The link below is literally the biggest collection of JC Prelim ‘A’ level papers I have ever seen. Both H1, H2 and even the occasional H3 exam paper can be found, for multiple subjects. Do download while it is still available!
This weirdly titled Google Drive (“Electric Boogaloo”) contains a mega-database of JC Prelim papers for most if not all subjects, even esoteric subjects like “Theatre Studies and Drama”. Exam papers ranges from H1 to H3, and from the years 2008 to 2019.
Do download in advance if you need the material, from experience such Google Drives tend to “disappear” from time to time.
On the other hand, some games are educational but not fun!
This very popular website Cool Math Games is a combination of fun and educational!
Benefit of Cool Math Games
Their games are all browser-based, there is no need to download anything. It can be played on your Internet Explorer or Chrome browser.
They have a wide range of different games, ranging from Numbers, Logic, Trivia, and Strategy.
Their games are kid-friendly and educational.
Cool Math Games Example
This games “Swap Sums” is suitable for lower elementary school kids (age 5-10). It starts off easy, but the later stages are actually quite challenging. For example, the stage below actually requires some thinking to get it right.
This is the Swap Sums game from Cool Math Games.
Cool Math Games Review
Children naturally love to play games. When I was a child, my favorite activity was to play computer games. Hours can just fly by when playing games. When playing games that are educational at the same time, it can hugely benefit a child in terms of increasing his/her interest in the subject.
Hence, parents are encouraged to let their child play educational games, such as Cool Math Games, to relax as well as to learn. Most children learn better when the content is fun and engaging.
Recently, bought a suspected fake SanDisk Micro SD Card on Qoo10 (Singapore online retailer).
Apparently, fake Micro SD cards (used for cameras as storage) are very common, even on Amazon and eBay. A popular estimate is that 1/3 of all micro SD cards on the market are fake!
The one I bought was a 16 GB SanDisk microSD card. Basically, according to this website, “The 16GB SanDisk branded item is a fake. There is no 16GB micro SD product in the SanDisk product line — it is a fake.”
What made me quite angry is that not only it is fake, it couldn’t work as well! (If it were fake but worked well, I could close one eye…) Both my Xiaomi Camera and also the card reader I got could not even detect it. The card reader with the fake microSD card could not be detected by either PC or Mac.
I think the main visible difference between the real SanDisk Micro SD and the fake is that:
The real microSD card has a imprinted rectangle box on its flip side (see the 1st video below for more details, the real one is on the right).
If you shine a light on the front face, it should say “Made in China” for the real Sandisk microSD card (see the 2nd video below).
Other differences include:
The fake microSD card has lower speed and volume (for example it could be rated 64GB but only has 2GB space!)
Lower printing quality on the fake microSD card
The authorities should really crack down on these fake SD cards. It is getting harder and harder to distinguish between the real and the fakes, some of the fakes replicate 99% of the real product up to the design of the packaging.
Quite interesting, and makes a bit of sense too. In this new age where almost everyone has a degree, not having a degree may in fact stand out (for unique career paths)! It carries risk though, naturally.
When her son Jairus, 12, said he wanted to be a Twitch streamer, Evelyn was confused. According to Toggle, she did not know about the online streaming platform for gamers.
She called him a “thinker” — he had told her that if he started his career now, it would be established enough to be profitable by the time he turns 21.
Her son then pointed out that a degree would be irrelevant to his career, which Evelyn said was fine.
Evelyn Tan majored in Math in NUS
Not many people know this, but actress Evelyn Tan once majored in Math in NUS, and graduated successfully. “Upon graduating from the National University of Singapore with a degree in mathematics, Tan joined the fifth edition of Mediacorp’s Star Search in 1997.”
Étude Op. 25, No. 1 in A-flat major by Chopin is also called Aeolian Harp Etude. It is considered to be of moderate difficulty among the etudes, but can be difficult to play perfectly…
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.
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 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.
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.
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.
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.
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.
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
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.
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.
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.
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
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!
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.
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!
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 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.
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.
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 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”.
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
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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).
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).
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.
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.
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.
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.
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!
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“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.
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.
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.
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?
if and only if its minimal polynomial is a product of distinct linear factors over 
be an 
matrix. The characteristic polynomial of 
, is the polynomial defined by 
where 
.
Mathtuition88 