Scientific Scribbles

The voice of UniMelb Science Communication students

How Computers Generate Random Numbers — Is It Really Random?

The common way to generate the random number in real life are rolling a dice, flipping a coin and even talking a number without thinking. What about computer? It neither has dice nor coin also it cannot think as human brain. If it is just a piece of code, isn’t it possible the numbers the computer generates could be predictable? Where does the “randomness” actually come from?

Dice Image credit Flickr user: jchapiewsky


Why we need random number?

Gambling, Lottery and unpredictable results in a computer game are the applications that firstly come up with when we talk about application of random number. Aside from them, randomness stands a really essential role in the cryptography. Verification code, for example, is exactly based on the randomness. We need to create some random characters to prevent the operations from script code (purchase limited tickets online). Cryptography requires the way to generate the number is unpredictable to attacker thus the number can be regarded as random.


What is random number?

To answer how to generate a random number, we need to know the definition of it. In cryptography, we group the random numbers into two types, depending on how they’re generated: “True” random numbers and pseudo-random numbers.

True random number means it is impossible for attacker to predict. Computer measures some physical phenomenon that takes place in the natural. These physical phenomena are validated to be unpredictable, hence the number computer measures are pure random. For example, some unpredictable processes like thermal or atmospheric noise and radioactive decay of an atom. People cannot figure out the rule of the fluctuations of thermal and atmospheric noise nor when radioactive decay would occur.

Pseudo-random numbers are an alternative to “true” random numbers. It relies on a value and a function to create a random number. In this case, computer does not gather any information from outside, and totally depends on computer itself. Apparently, it is predictable. If an attacker, for example, knows the algorithm and value that a pseudorandom number generator uses. He can work backward and determine the pseudorandom number in a certain time.

Random Number Multiples – RGB Image credit Flickr user: Jer Thorp



Does that mean pseudorandom number is not a good choice?

As mentioned before, pseudorandom number is predictable in theory. However, it is not a bad thing in every situation. For example, in music player, random play is exactly based on pseudorandom number. It really doesn’t matter whether it is true or not. Even in the cryptography, pseudorandom number is secure enough in most cases. In practical, people will have many measurements to make the generator function really hard to disclose. In common sense, there are two criteria to evaluate whether the generator is secure enough. First, if calculations are greater than age of universe: 100 years or 1000 years to break it. It can be considered as secure. Second, if the cost of attack is far greater than the benefit. For example, attacker may be plan to break the verification code for booking some tickets without limitation. If it requires massive computation to break the generator function, attacker may give up cause the cost on high performance computer is quite high.

The interesting thing is, in some cases, we have to use the pseudorandom number. For example, the principle of car remote control device is based on the pseudorandom number. To ensure the security, the password of the car lock can be used only one time. Both remote control device and car will generate a new pseudorandom number to match as key for lock, hence the theft cannot open the car even he obtains the current password. In this case, we have to apply pseudorandom number generator, because we need car and remote control device to generate the same number at same time. As long as the value and generator function is known to both car and control device, this mission is quite simple to complete. However, with respect to the theft, it is a “true” random number cause the value and generator function are obscure to him.

That means, if the generator function is strong enough, the pseudorandom number can be regarded as a “true” random number.

Are we filling up the world with people?

Imagine for a moment that you are living in the cave ages. Your whole society consists of your clan, numbering perhaps a few hundred individuals. Modern luxuries we take for granted such as healthcare and retirement are unheard of.


And yet the unstoppable effect of time marches on, and you can feel yourself ageing as the years rush by. How do you deal with this inevitable decline? Who will care for you when you’re old and bent? Nurses? No, there’s no such thing in these days! Personal assistants paid for with a pension? You’re dreaming! No, the only people you can rely on in your infirmity are: your children.

And so, it would seem, that the best insurance you could have for a comfortable senescence is having a lot of kids. Particularly as half of them are likely to die before they reach the age of 5, and more still might be lost to random things along the way such as disease or cave bears.


For most of human history, this has been the case. Women have as many children as possible, expecting many of them to die. This led to rather steady rates of human populations across the globe for thousands of years. Everyone had a lot of kids, but a lot of those kids died. Life was hard.

If you were alive about ten thousand years ago, you would have been one of only about one million people on the planet. Less than a quarter of the population of Melbourne, spread out over the whole world. Over the next 9 500 years, populations grew slowly so that by the 1800’s numbers had reached one billion people.

And then the industrial revolution happened! With it came increased access to food and healthcare. Antibiotics and vaccines were saving a lot of lives. And the food! Agriculture was modernised by the industrial revolution and all these machines and fertilisers led to a healthier longer life for all. All of the sudden, children just weren’t dying as they used to!


Yet mothers kept popping out babies and as they survived the population boomed. From 1 billion in the early 1800’s it doubled by the 1930’s, doubling again by the 70’s and reaching the terrifying height of over 7 billion people alive today. It is a terrifying trend. If it continues this way, we’ll be like rabbits on an island, breeding with wild abandon until we’ve eaten every last green blade of grass there is and then slowly starving to death by the billions.


So, is this the case? Are we doomed to a hungry end? The answer of course, is no. Unlike rabbits we humans have the gift of foresight. Though we don’t always make use of it, our foresight has in this instance allowed us to predict our future population and plan for the worst. And as it turns out, the future doesn’t look so domed after all.

See, the thing about population growth is that it depends on two main factors: fertility and mortality rates. Births and deaths. What happened over the past 200 years to cause such an increase in the human population is that the death rates dropped dramatically, while the birth rates stayed the same. Those birth rates are now falling.

When all your kids are surviving, you don’t have to have ten children anymore. One or two will do. We see this trend right across the developed world. When mortality rates drop, and women get increased access to education and contraceptives, birth rates decline dramatically. Global birth rates have declined from 5 to 2.5 since the 1960s. Studies show that a full third of the global population growth is due to incidental or unwanted pregnancies. With an increase in female education, empowerment and contraception these birth rates will fall even further.


Increase in wealth and education is now a global trend, with many countries pulling away from their third world status and establishing themselves as emerging economies. This increase in wealth, food and education is leading to a global decrease in birth rates, to the point where birth rates and death rates are balancing each other out.

The current prediction by the United Nations is that by 2050 we will have reached 9 Billion people on planet earth. The good news is, they then think the global human population increase will plateau. We’ll all have our 2.1 kids and be happy! No more population rise!

This being said, we can never predict exactly how things will happen. New technologies are constantly on the rise, and the effects of climate change and unpredictable disasters, natural or man made, can throw a spanner in the works of even the most well thought out predictions.

All we really can do is wait and see. And in the meanwhile, strive towards education and wealth for all!

Antibacterial soap, have we gone too far?

Is washing your hands doing more harm than good?

soapWhen did soap turn into fudge? Image credit Flickr user: a- kang

Who doesn’t love being clean?

Hygiene is an important part of our day to day lives. We shower, brush our teeth, and if we’re really concerned and anal about appearing clean: floss, shampoo, condition and use deodorant.


Hopefully, you use soap.

Everyone uses soap, it is an intrinsic part of the daily routine, providing an easy and very mobile method of cleaning. So how could something so inextricably linked with health actually do the opposite?

Guns? Wasps?

wasp“Hey buddy, screw you” Image credit Flickr user: Pascal

Oversaturation of antibacterial components and ingredients?

The issue isn’t with soap or its function, but with its ingredients. The powerful soap lobby(?) may not want you to know it, but the inclusion of certain antibacterial products, mostly triclosan, may be contributing to the downfall of humanity as we know it.

Have a think about your role in this.

Those of you who considered not washing your hands ever again, that’s disgusting.

Regular, non-antibacterial soap, is fine. In fact, research has been unable to prove soap containing triclosan, one of the most common antibacterial components, is actually any better at cleaning your hands than standard soap and water.


What does anti-bacterial soap do then?

These antibacterial soaps do have an effect on bacteria and infections, just not the effect you’d want. Years of studies and research have looked at the potential for increased use of these antibacterial components and products to contribute to the development of antibacterial resistant superbugs.

giant-bug“Your penicillin doesn’t scare me. This is my house now”. Image credit Flickr user: Steven-L-Johnson

Although developing immunities and resistances over time is a natural response. Increased use and oversaturation of antibiotics and antimicrobials can speed up this process. If you’ve ever been proscribed a course of antibiotics, your doctor should have made sure you knew to completely finish the prescription, regardless of symptoms. This is important as not fully removing the bacteria from your system can allow them time to develop further resistances. In addition, using them unnecessarily or recklessly (such as in soaps), can also contribute to these developments.

As far as soaps go, one of the main culprits, as mentioned, is often triclosan.

triclosanImage credit Flickr user: Mike Mozart

Triclosan is a biocide, and one of the most common antibacterial ingredients. Surprisingly, the health impacts of continued triclosan use are not well understood. For a product so pervasive in hygiene products, such as soaps and toothpastes, to present so many unknowns is worrying. Recent research has linked triclosan linked with potential cancer risks, correlation between triclosan and allergies in young children and interferences with microbes in the gut of zebrafish, (commonly used for toxicology modelling), on top of the potential development of antibiotic resistant bugs.


What should we do?

Some of these issues are being taken care of for you. The US Food and Drug Administration, (FDA) recently banned companies from marketing over-the-counter antiseptic wash products which contain any of 19 specific ingredients, including triclosan.

While there has been no official reaction in Australia, organisations such as the Australasian society for Infectious Diseases, (ASID), and the Australasian College for Infection Prevention and Control, (ACIPC), have backed the FDA’s move. Hopefully, signalling the start of a greater response.

As for right now, don’t use antibacterial soap. While they haven’t been banned in Australia, and the evidence of negative effects may need further study, considering that studies have shown triclosan-based products to be no more effective than regular soap and water, why take the risk?

Additionally, hand sanitisers can be an effective method if soap and water aren’t on hand. Just make sure that you use sanitisers that are at least 60% alcohol, as recommended in this handy how-to guide for hand-washing.

beer“4%? My sanitiser is stronger than that”. Image credit Flickr user: N I c o l a

Please don’t drink hand sanitiser.

And wash your hands.


Further easily digestible information, in infographic form

Australia’s place in all this

How resistances to antibiotics can spread

Return to the wild

Saving threatened wildlife from the brink of extinction is no easy feat. Despite all efforts in conservation biology, the 2014 Living Planet Report claimed wildlife populations have declined 52% over the past 40 years. (Umm..massive!) Surely there’s other answers to buck this trend. So, how about embracing rewilding? And what even is this? A bit of a tongue twister to start with – try saying “rewilding rhino” three times quickly and you’ll see what I mean.

Sticking back what was once wild and free? Image credit: RachelEFrank via flickr
Sticking back what was once wild and free? Image credit: RachelEFrank via flickr

The idea of rewilding was born and raised in the global north – where human-driven development and disturbance has altered landscapes and removed magnificent beasts over thousands of years. It takes on a direct, proactive approach to conservation, as opposed to more traditional preservation strategies, by reintroducing a species back to the wild; free to roam and do their thing! It is particularly focused towards those species on the brink of extinction or where an ecological service across a landscape is currently missing, i.e introducing mega-herbivores for grazing.

Rewilding: smart innovation, nostalgia or just plain mad?

Rewilding certainly poses some radical ideas, which quite obviously generate controversy among scientists and the general public alike. Think rhinoceros and elephants roaming Scandinavia for example!

However, most proposals are a little closer to home. The idea behind rewilding theory is to restore ecological processes by getting keystone species and apex predators back into a dwindling and damaged ecosystem.

It may be easy to romanticise the notion of tapping into long lost cultural legacies, such as wolves and wild boar roaming Europe again, but in realistic terms, it would be foolish to dismiss the inevitable social challenges of this new unconventional tactic. Most critics find it hard to dispute the theory entirely, just stress that it requires rigorous assessment of all risks, issues and logistics before implementation. The benefits seem to far outweigh the risks.

There are a few other blockages however…

Most of our global conservation frameworks were established last century and provide little room for creative or innovative concepts, nor much incentive to branch into this area. But for the growing number of threatened species at stake, it is time for these centralised institutions to modernise and to allow some regulatory flexibility at more local scales.

A political game

Much of the world’s legislation around nature conservation is becoming outdated and experts are starting to say revisions should include the possibility of experimental rewilding. Those scientists advocating for rewilding need to present feasible policy options that can be taken seriously against the somewhat rigid institutions and our risk-adverse governments. Otherwise ideas taken forward might be quickly squashed.

The good news is, some areas are gaining traction where we could learn by. The non-for-profit, Rewilding Europe, have been taking massive steps in the rewilding game. With an increasing amount of rural land becoming abandoned, this group are buying it up to turn Europe back into a wild place. One million hectares already in fact! The US and Briton also have programs forging ahead.

Wolves are back in Yellowstone. Image credit: doublejwebers flickr
Wolves are back in Yellowstone National Park. Image credit: Jeremy Weber via flickr

Does native matter?

To mechanically or artificially restore a natural functioning ecosystem by introduction of selected fauna species is fraught with many unknowns and risks. When playing with non-native substitute species, the stakes are even higher. One idea, (call it crazy or not), is releasing the Komodo dragon in Australia to re-establish certain ecological order that was lost with the extinction of a  megafauna goanna species.

Closer in time than megafauna period is the wave of extinctions Australia has faced since European arrival. This ancient land is home to some pretty ancient animals, including of course the oldest mammals on earth being our marsupials and those all-bizarre egg laying, milk producing monotremes; the echidna and platypus. So it’s no wonder they’re a little more sensitive to a new world of exotic pests, diseases, habitat destruction, population booms and pollution!

Therefore, rewilding poses an option that’s not all far from the time such species were shunted out or fully exterminated. It’s too late to bring back the Tasmanian tiger (or Thylacine), but Rewilding Australia believes reinstating quoll and Tasmanian devil populations over Australia would improve ecological resilience while improving the species’ population health.

The devil you know… How about these in Victoria soon? Image credit: Andrew Scott via Flickr
The devil you know… How about these in Victoria soon? Image credit: Andrew Scott via Flickr

All of this spurs the question, just what kind of wild nature do we want for our future? Are we content with zoos becoming living museums telling tales of where wildlings once walked or do we actually try to turn back the clock and let them live as they once were in the wild? Whether it will work, what it will prove or and for which animals all depends.

One thing out of this is for certain – the potential to reinvigorate nature education and look at our own place in nature as human beings. Given the chance, rewilding could really liven up public debate and increase community engagement with nature conservation. I’m excited!

For an interesting watch on this topic, check out the recent episode of Foreign Correspondent on ABC iVeiw.

Sommeliers: Legitimate skill or an excuse to drink more?

The concept of fine wines has always eluded me. As I sit here, drinking my $8 wine I realise the whole thing is lost on me.

Personally I can’t justify spending $60 on one bottle of wine – nor could I tell you the difference between that and a $20 bottle. My $8 glass has me thinking, if I can’t appreciate fine wines like Dom Perignon or Penfolds and taste the subtle hints of *insert exotic flavour here* – can anyone? Are wine connoisseurs  – sommeliers – actually talking nonsense?

Penfolds Grange – a highly respected brand and type of wine. The Vintage 1958 Penfolds Grange retails at $34,900 from Dan Murphy’s, Australia.



So, naturally, I did some digging. To my surprise, it turns out there is some merit to what the wine professionals are talking about. Interestingly, sommeliers actually activate a different part of their brain when sampling wines. A study in Italy – using members of the Italian Wine Association (Enoteca Italiana di Siena) as in THE wine people – were tested against “naïve” tasters. Naïve being someone like me with no training or knowledge of fine wine. How did they test this? Why, by measuring their brain waves of course!

They strapped their subjects (ethics approvals well in place) and essentially force-fed them various samples of either wine or a glucose liquid (I volunteer as tribute!). Results showed differences between the naive and the professionals brain scans. Both naive and sommeliers had the same patterns of brain activation during tasting, and they could easily identify the difference between wine and glucose. However, during the aftertaste phase, there was significant difference with the naives and sommeliers activating different parts of their brain during this phase! The sommeliers extensive training has allowed them to increase their sensitivity to combined olfactory and tasteWine tasting and scoring. Credit: Concour Mondial de Bruxelles perception. Basically, their long training has allowed them to isolate and carefully analyse ‘tastes’ to detect finer things than the naïve tasters. So, after they swallow during the ‘aftertaste’ stage, their olfactory senses are heightened and can detect more acute things the naive tasters couldn’t.

So what does it actually mean? Should we care what they say?

Well, it means that they have the ability to isolate flavours and aspects of what they’re tasting by using their olfactory senses and there is certainly knowledge behind what they’re saying.

It’s interesting to remember that we (humans) are also easily influenced by our emotions, the weather – and even music! Texas Tech University showed that by playing classical music in a liquor store, it encouraged patrons to spend more on wine than if they played popular hits. In a different study, both professionals and regular consumers tried wines and were given a positive or negative score awarded by a well known wine critic before tasting.  When tasters were told a wine ranked high before they sampled it, it generally influenced them to score it higher. Similarly, when the same wine was given a negative review prior to sampling, tasters scored it negatively.

Blind taste testing. Labels and brands are hidden before sampling. Credit: Lehigh Valley Wine TrailThis isn’t a new concept. There have been various tests where consumers sampled beer, tomatoes or even protein bars and were given  ‘blind tests’ or negative information about the product. More often than not, they reacted negatively to the product or couldn’t tell the difference between high or low quality products.

So, can we trust sommeliers?

Put simply? Yes. Highly trained sommeliers are more sensitive than we are to subtle flavours with their heightened olfactory senses and taste receptors, so there’s a fair chance they know what they’re talking about when they say they’re tasting something we’re not.

The take home message from this, personally, is if you walk into a liquor store to buy a bottle of wine be careful of the music playing.

Now if you’ll excuse me, I need to refresh my $8 glass.


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