Monday, November 17, 2008

Myself in Pictures

While I appreciate the semi-anonymity I have in the blogosphere, here are a few pictures taken while I was out with my sweet fiancee.

I like these pictures. They were taken in the final fading days of autumn, a few weeks ago. The colours are quite lovely, and the pictures were tastefully composed. Maybe this gives you a little insight into myself.



Being a Good Potluck Guest

As promised, I am continuing my posts on potluck etiquette, offering some advice based on my humble experiences.

Let's start with being a good guest, since most people will be a guest at a potluck before they are a host (at least the way I think of it). Being invited to a potluck is a bit unlike other social events since you have a clear responsibility of bringing something. One does not simply show up to a potluck, as one would be outcast immediately. Or just receive some nasty glares from other guests. Either way, the obvious first piece of advice is to make sure you bring something to a potluck.

Now the question becomes what to bring. In my experience, this is difficult for most people, mainly because they "don't" cook or "can't make anything good". If you, dear reader, can relate to this line of reasoning, do not fret. There a few avenues you can take to remedy this problem, which usually involves talking to the host or to some other guests. First, you should ask them what the expectations are for this potluck. If it's a relatively informal gathering where the food is merely a means to an end (of having a great time), then perhaps bringing snack foods, alcohol, or a ready-made, store-bought dessert is a possibility. These are easy things to bring, as you just have pick them up from your favourite grocer and remember to bring them. If the event is somewhat more formal, and food is a higher order of the day, then you may want to bring something you have prepared yourself or a classier store-bought item, such a fine wine or more decadent dessert. The last case is where the host has something particular in mind for some or all guests to bring, in which case you may have already been volunteered to make something. This is either a blessing or a curse depending on your esteemed host. That delicious three bean dip or blueberry fruitcake may taste good and impress, but it could also take time, resources and money to prepare that you just don't feel you have.

In any event, make sure to let the host know about your comfort level in preparing something. You may be able to bring utility items such as soft drinks or paper plates in lieu of actual food. You may also be able to avoid getting locked into preparing something you do not want to. As with all social aspects of humans, communication is key, so talk to the host if you're sure of the expectations. Also make sure you know of any dietary restrictions, so you don't bring bacon-wrapped shrimp to a kosher party. This could be awkward for you and other guests, so be mindful. On the other side of the coin, make sure the host and possibly other guests know about dietary restrictions you have.

The only aspect to being a gracious guest is how you actually arrive and interact at the event. Make sure you're punctual, which should be an obvious point. Also remember to let the host know of any special equipment or preparations that should be done before you arrive. There are instances where it makes more sense to prepare or finish a dish on-site at the event. If this is the case, make sure the host knows about it! The last point is to be polite and courteous to other guest and dishes. Don't turn your nose up at other prepared dishes, as this is rude. Nor should you offer nonconstructive criticism of other dishes; if you have nothing nice to say, say nothing at all. In my experiences, most of the dishes prepared are actually really good. Potlucks are a perfect chance to experience new foods and perspectives, so don't ruin things by being a snob or an ass. Be yourself and enjoy!

In my next post, I'll give some tips for preparing good dishes and provide some potluck-friendly recipes.

Tuesday, November 11, 2008

"You can use math to do that?" Part 2

In the previous post of this series, I introduced the idea of mathematical modelling and gave a simple model of population growth of bacteria. We ended with the expression

P(t+1) = P(t) + bP(t) - dP(t) ,

where P(t) is the population at (discrete) time t and b and d are the positive birth and death rates, respectively. Now that we've used our biological knowledge to come up with this equation, let's use some math knowledge to learn more about it and what it can tell us about bacteria growth.

First, we can collect like terms, and make the expression simpler. This is like using the fact that x + 2x = 3x, since we have like terms of x and 2x. Since most people become physically ill when algebra is mentioned, I'll just write down the collected terms in our P(t) formula, and get

P(t+1) = (1 + b - d) P(t) .

This "new" form of our population equation can tell us something about what will happen to our population in the long-run (that is, as we let t get larger and larger). The above expression is an example of a geometric sequence. A sequence is just a list of numbers, following some pattern. In a geometric sequence, each number in the sequence is related to the previous one by multiplying it by a constant value. Using another mathematical trick, let's make a substitution, and let
k = 1 + b - d ,
so that our equation really is

P(t+1) = k P(t) .

In this form, we can really see what will happen to our population. If we start with some initial population size, such as P(0) = 100, then using our simplified equation above, we can find P(1), which is
P(1) = k P(0) = 100k.

Then

P(2) = k P(1) = k (100k) = 100 k^2

and

P(3) = k P(2) = 100k^3

and so on. If we look at the pattern here, we see that there is a general equation for

P(t) = P(0) k^t

if the initial population is P(0) and k = 1+ b - d. If you're still with me at this point, you might be asking "so what does this get us, exactly?". Well, if we know what k is, it tells us a lot. The growth in the population depends completely on what k is, which depends on what b and d are. This makes sense: the birth and death rates determine what will happen to the little bacteria culture we have growing. Let's look at an example to see how.

Suppose that b = 0.2 and d = 0.1, meaning that k = 1 + 0.2 - 0.1 = 1.1 in the equation above. Then if we look at powers of k, we get (1.1)^2 = 1.21, (1.1)^3 = 1.331, (1.1)^4 = 1.4641, and so on. You can check for yourself that each power gets larger, and is larger than the previous one. That means as t increases, (1.1)^t is also increases, and in turn, P(t) is increasing. This makes some intuitive sense, since this is a result of the birth rate being higher than the death rate. Since at each time step there are more births and deaths, the population will increase indefinitely. This is a little bit unrealistic, since there are limits to growth (the amount of food the bacteria have available to them, having no more space in the petri dish, etc). This is due to the simplicity of the model, by the strong assumption that birth and death rates are constant in time. Still, the model does tell us something that makes sense and is realistic.

Let's look at the opposite case now. Suppose that b = 0.1 and d = 0.2 so that k = 1 + 0.1 - 0.2 = 0.9. If we look at powers of this k, we get (0.9)^2 = 0.81, (0.9)^3 = 0.729, (0.9)^4 = 0.6561 and so on. Here, as t increases, (0.9)^t is decreasing, and since it can never be negative, it will shrink smaller and smaller until it is almost zero. Biologically this means the bacteria will eventually go extinct if there more deaths than births at each time step. Again, this is exactly what you'd expect. The model, while pretty simple, makes biological sense, and so if our assumptions are not too strict, it would be a good model of bacteria growing in a laboratory.

So, there's a simple model of population growth. Of course, there more complicated models, like the logistic equation, which has rich mathematical properties as well. Personally, I think this area of study is really cool. Math is as useful as it is fun!

Wednesday, November 5, 2008

Potluck 101: The Basics

I love entertaining and social events in general, particularly when they come together well. Your friends come, they bring other cool people, you mix and mingle, eat, drink and be merry. Frankly, I can't think of a better way to spend an evening but with good people at a good party/get-together. There are lots of options you can take when it comes to organizing such an evening, from the ridiculous to the sublime. When you are a student and so are your friends, a potluck is a good way to go. As a person who has been to some good potlucks, I thought I'd have a little series of posts on the in's and out's of this form of entertaining, as I have some experience in such things. I'll go over the basics, as well how to be a good host, a good guest, and some other tips along the way. Who knows, maybe fun will be had. But let's start at the beginning.

Essentially, a potluck is a type of party where every person invited brings an item of food or drink of their choice to share collectively with other guests. It's exactly what it sounds like, where you have to see what "luck" you have as to what's in the "pot". There are a few advantages to having potlucks. One is that you do not have to prepare an extensive menu for food and beverages while having potentially several friends over for a gathering. Another is the cost of having refreshments is lower on the host (which is good if you are a cash-strapped student). And of course, potlucks tend to be less formal events, which can bring an air of relaxation and mirth (especially when that really cute girl you told your friend to invite brings a spectacular dessert). Among the downsides are guests sometimes feeling obligated to make something "good" or "homemade", which can be testing for those culinarily-challenged, and making sure that not everyone brings the same or similar item. Nobody wants a meal of a dozen Caesar salads.

In general, potlucks are good event to plan if 1) cost is an issue, 2) you may be expecting a relatively large crowd and do not have the resources to prepare for them, 3) guests you invite enjoy cooking/baking, or 4) individuals who you would invite to such an event would actually enjoy it, as in, for example, no outrageously picky eaters. They are also a good basis for themed parties, where everyone brings a theme food item (eg East Asian cuisine, dessert). Or you can turn some other party into a potluck just by asking beforehand that guests bring particular items, which eases the obligation of the host. The biggest question you should ask yourself before organizing a potluck-style event is "Will this go over well with the guests I intend to invite?". If the answer is a no, perhaps consider something else.

I'll conclude with some general tips for potluck or potluck-esque events.
  • Make sure you ask guests about allergies or dietary restrictions beforehand so guests know not to bring particular dishes. Don't invite a vegan to a "meatluck".
  • Ask guests ahead what they plan on preparing. This is to avoid having multiples of the same dish, and to add some variety and balance to the meal.
  • With any party or event, invite your guests carefully. Inviting people who have no interest in cooking or enjoying other people's food will likely lead to a downer of a time, so make sure you invite individuals with whom you will have a good time with.
  • On the other side of the coin, do not be too draconian when asking what individuals bring. If they do not like cooking or really don't want to prepare a certain dish, don't force them to. This could put a strain on your enjoyment and theirs at the actual event.
  • If necessary, establish who will bring needed non-food items (cutlery, cups, corkscrews, etc).
  • Make sure there's enough food and drink to for the guests invited. Usually, in my experiences, this is not a problem, but it could potentially be if people cop out and bring nothing but napkins or a bag of chips.
  • If necessary, establish beforehand what happens to leftovers when everyone has eaten. This can lead to surprisingly tricky situations, so make sure that people know what the deal is.
  • Be polite, courteous and have fun!

"You can use math to do that?"

So, after a short hiatus (due to sketchy internet connections), I thought I'd continue along with some posts relating to my current position as a math grad student. Now that you've had a small taste of mathematical biology, you might be asking yourself "That sounds really interesting and stuff, but how do you actually use math for that?". This question comes up a surprising amount when it comes up that I'm an applied math person, and have done or seen projects on epidemic spreads or why individuals cooperate with one another. Most people just don't see the connection between mathematical modelling and "real life" problems. So, as a primer on this, let's talk about mathematical modelling.

The main idea behind mathematical modelling is to try to describe a problem or situation using mathematics and then gain insight from the maths that you've come up with. Think of it as translating the problem into another language, a language that you can work with to find a solution. Once you have this solution, you can just translate it back and see what it says. The goal is to make sure that the translation in either direction is good, and that nothing gets lost or distorted. Usually, this is the toughest part: coming up with a good model to begin with (and when I say model, I mean a set of expressions describing the problem, not Tyra Banks or Christine Brinkley). Once you get a solid model, usually you can analyze it shed some light onto the problem at hand. Perhaps this is a good time to lead by example.

Suppose I'm a biologist, and I am studying bacteria in laboratory settings. In between the lavish late nights I enjoy in such a profession, I want to understand what influences bacteria population growth or extinction. Here, there's at least two ways I can look how bacteria grows
  1. Collect data from the bacteria in petri dishes, and make some plots with it.
  2. Create a mathematical model based on what I know about bacteria.
Of course, I could do both, which would really better my understanding of bacteria population growth. But, since I'm a biologist that loves mathematical models, I'll try the second approach.

First, I'll need some variables to work with. Suppose that P(t) is the population of the bacteria at time t. I want to find an expression for what P(t) for any general time t, so the goal is to find a mathematical model that represents this.

Now, I'll need to make some assumptions.
  • Assume the population changes at regular, discrete time intervals (for example, the population only changes every hour, and not all the time). This may seem a bit strong ("bacteria reproduce all the time, like a million times a minute!" you say) but this is part of translating the bacteria problem into math. I have to make some kind of simplification or else I won't have anything to work with.
  • Also, I assume that the only way the population can change is by bacteria reproducing or dying. This means that I can't just "add in" bacteria once I've started, nor can they just "appear" out of nowhere. They have to be the result of reproduction.
  • Finally, I'll assume that bacteria reproduce and die directly proportional to the population size. In layman's terms, this means that the more bacteria there are, the more will reproduce or die at any time step.

So, with these assumptions in place, I can now develop a model. The simplest model has the form

P(t+1) = P(t) + births - deaths


which means that my population at the next time step is just the population at the previous time step plus the increase from births and less the decrease from deaths. In population dynamics, many, many models start out with "births - deaths".

If assume that the birth and death rates are just a constant proportion of the population at time t, then I can turn this into

P(t+1) = P(t) + bP(t) - dP(t)


where b is the constant birth rate, and d is a constant death rate, and both are fixed constants. What these mean is that at each time step a proportion b of the population reproduces (remember, these are bacteria, so let's just say that they divide to reproduce), and another proportion d die.

So, there is it, I've come up with a mathematical model of bacteria growing. I've now translated the problem of how bacteria grow into mathematics. But that's a lot of work for one day for mathematical biologist, so in my next post, I'll look at working with this model to get some results out of it, and translating those back into real answers.

Friday, October 31, 2008

And now for something completely different

Now, just because the first posts in this blog of mine have been rather serious doesn't mean I can't lighten up. In fact, I'm rather a funny fellow sometimes.

Here's a clip of a well-known lead actor of an American medical drama. Perhaps this may give you a different perspective of him.



As a comparison, here's the same clip which was made for the pilot for Fry and Laurie, a British sketch comedy show:



He's been on such great shows such as Black Adder (with Rowan Atkinson) and Fry and Laurie (with, obviously, Stephen Fry). I highly recommend those programmes as well.

Oh British comedy. Nothing quite like it!

Wednesday, October 29, 2008

Disease, Heart Attacks and Grizzly Bears: An Introduction to Mathematical Biology

As I've mentioned in a previous post, I'm currently completing a master's degree in mathematical biology. Since this isn't the first thing people see opening up the newspaper or gossip magazines, I thought I'd give you an idea of what exactly mathbio is and what it entails.

The short version is that mathematical biology is exactly what it sounds like: using mathematical methods and techniques to solve problems in biology. What kinds of problems, you ask? Almost all areas of biology can be found in a mathematical context, from ecosystem management to immunology to pure evolutionary theory. Pretty much any area you could study in biology has had someone, somewhere look at things from a mathematical perspective.

Personally, I think that this is a great thing, both on the biological side and the mathematical side. The biology community gets new angles to view problems from and hard quantitative results that can be the basis for experiments and further hypotheses. The mathematical community gets motivation for problems and for more pure mathematical research areas. And everyone gets solutions which could potentially save lives and better the understanding of the world we live in. Mathematical biology is undergoing a revolution of sorts, which began earlier in the 20th Century, and whose fruits are being realized now at larger scales, and not just in the ivory tower. Let me give you a few examples to illustrate this.

Take mathematical epidemiology. In Canada, this seems to be the largest subfield of mathbio (but I could be wrong). This area looks at the study of infectious diseases and epidemics and tries to model them using equations. The goal is to better understand how epidemics begin, persist, and what can be done to prevent or constrain them. Using mathematical models allows researchers and medical professionals to consider different scenarios and look at specific factors and their impact, without any risk or harm to the general population. For example, I've seen models looking at factors causing and preventing Mad Cow disease in livestock, of HPV (human papillomavirus ) and the effectiveness of potential vaccination regimes, and of the spread of HIV in parts of sub-Saharan Africa. These are certainly real issues with real consequences, and solutions are being developed by applied mathematicians and health researchers.

Or perhaps you'd be more interested in mathematical ecology. Ecology is the study of how species interact on a macro level in ecosystems, and what affects the population growth or decline of species. Modelling predator-prey or competing species interactions are classic examples of mathematical biology. One of the most studied examples is the dynamics of lynx-hare populations in the Canadian Arctic. The hare is prey for the lynx, and as one population changes, so does the other. Salmon are an example of competing species. Salmon farms are usually situated near wild salmon habitats, so they use some of the same resources, and there is a chance that either the farm or wild salmon could wipe out the other, each case with negative consequences. I have seen papers and presentations of both ecological situations. Even more interesting is the fact that such ecological modelling has yielded some rich mathematics, specifically for the fields of dynamical systems and chaos theory. Perhaps this shows nature has much to show us about the intricacies of mathematics.

If neither of those took your fancy, perhaps you'd be interested in mathematical physiology and medicine. This area sees the mathematical modelling of physiological processes and medical treatments, and attempts to use math to gain a better understanding how the human body works and how we can better heal it. One big area of research here is tumour development and growth. Here, mathematics and related methods are used to study how tumours grow and sustain themselves and how they can be stopped or at least controlled. Related to this is the study of cancer and how it begins at the cellular level. I have also seen research done on causes of heart attacks and irregular heartbeats and how a to design a better kidney dialysis machine, both using good old mathematics. This I think could be the most promising area of mathbio research, since it could benefit almost everyone by furthering our understanding of medical treatments without using real patients or scarce medical resources. And again it could also give more insight to underlying maths that are used to model such problems.

I should mention that my research isn't really in any of these research areas. I'm more into evolutionary game theory and the evolution of cooperation, which is a pretty cool topic in itself, loosely based the question "Why bother helping others out when you just free load instead?". I'll give more insight to this question and my rears later on. But I hope that I've at least shed a little light on this thing called mathematical biology. But there's lots more than what I've written above. From tropical diseases to why we have sex, a mathbio researcher has used math to understand it.

Thursday, October 23, 2008

"I'm Thinking of Going to Grad School"

So, you're thinking of going to grad school. I think that's great, because in some ways, being a graduate student is terrific. However, in some ways, being a graduate student is a bit of a crappy career path. It really depends on your motivation, your career goals, and your opinions on education in general. It's not a trivial decision.

Basically, my opinion is this: if you don't like school or "academia", don't go to grad school. You probably won't like it, and will likely hate it. If you enjoy school and are good at it, you might like grad school, but there are other considerations to be had too.

So, without further ado, here's the breakdown of reasons to go and not go to grad school:

Reasons to Go:
  • Pursuing an academic career: This one is pretty obvious. If you want to have a job in academia as a professor or researcher, you'll need to start you journey in grad school. Doing some postgraduate work is a good way to figure out if going down this path is right for you. Talking to other grad students or professors is also a good idea. The academic life is something of a calling, but look into it if you think it's for you.
  • Gaining experience for a particular career: While a Bachelor's degree is a good thing to have on your resume, there are a few jobs that typically look for more. For example, some jobs in finance or investment banking look for individuals with Master's or PhD degrees. Some administrative positions in education require at least a Master's. And I've also heard that you'll be taken more seriously as an author with an advanced degree. In some disciplines such as mathematics, graduate level education is much different from undergraduate, and employers may be looking for something specific. In all of these cases, the knowledge and skills you'll acquire in graduate work will be helpful, and be put to good use.
  • Continuing previous work done: This is perhaps an unusual reason, but still a valid one. You may have done some work for a professor or researcher during your undergrad, as a research assistant, programmer or TA. If it went well, and there's still more work to be done, maybe they'd take you on as a graduate student. You gain a good reference and an advanced degree for your resume. They get continuation on their work and an established collaborator. For some people, this is a win-win situation. I personally think this benefits everyone involved, and can foster strong professional relationships.
Reasons to Not Go:
  • "Couldn't think of what else to do": This is hands down the worst reason to go to grad school. Indifference is a terrible thing to have in academia. If you're not "into" your research, it will show. It is hard to be motivated and take initiative to read current journal articles on narrow topics such as pair approximation methods in lattice-based population dynamics models. It'll also be hard to prepare for tutorials for dozens of first year engineering students, some of which are wondering why they lost marks on that one question they knew they got right, and others of which get up and leave noisily as you try to demonstrate how to compute a matrix inverse. Believe me, if you really turn your nose up at either of these situations, perhaps graduate work is not for you.
  • No interest in research: If you don't like the idea of doing hardcore academic research, perhaps consider another career option. Research is the order of the day as a graduate student (and in turn as a professor). If you're writing a thesis, you must come up with some original research to publish. If you're taking a course-based degree, you will still have to read academic papers and books. In any case, graduate study is much more independent than undergrad. Even if you like the teaching aspect, disliking research will not make for a good time in grad school.
  • Money: It has to be said: If you want to make a lot of money, don't go to grad school. You will be poor. Even if you score a major grant or scholarship, you will make less than entry level wages. People who want a corner office on the top floor and a posh urban loft typically don't go to grad school. They go to the so-called "corporate" world, right after college or university. Wanting to make a lot of money isn't bad and I'm making no judgments here, but I can say that you probably not enjoy the grad school life. I certainly know people who went to work right after their first diploma/degree, and they couldn't be happier for it. You just have to know yourself and what you want. The upside here is that your career prospects may improve if you have an advanced degree, so you may need to do a cost-benefit analysis to see if it's worth a few years of have a "lower" income.
This list is by no means exhaustive, but hopefully it paints a picture of what the grad school life is like. I can say that I think I make a good decision for myself. On the whole, I love what I'm doing right now.

Tuesday, October 21, 2008

"So, what are you going to do with that?"

This is probably the most annoying question that I get asked on a semi-regular basis. I'm finishing a Master's degree in applied math, and I'll be out looking for work or more school in only a few months. Clearly, I'm asking myself this question as well. But answering this question is tricky sometimes; it's not easy to be specific, and sometimes my response may appear flaky. The result is some awkward situations when "what I do for a living" comes up in oh so casual conversation. Also, saying that I'm a graduate student leads to some funny reactions. Here's why I think this is the case.

First of all, people really don't like math. Some people would rather boil their hair and drink the broth than talk about math. They hated it, had a bad teacher experience, failed some courses or just plain "didn't get it". This means that saying "I'm a math student" or "I do research in math" kills social interactions almost instantly. People just aren't interested. That's why I sometimes say I do mathematical biology, because at least some people like biology. Or that I research the evolution of cooperation, of why animals and people cooperate with one another. That at least goes over well sometimes. But in general, mentioning math is cocktail party suicide. I think this is really unfortunate, but such is life.

Of course, saying I'm a graduate student doesn't fare much better. I think that individuals who aren't in or have done postgraduate work get a little confused by this. They hear "student" and think "poor, unemployed, possibly lazy, but working towards something good hopefully". But there's also the "graduate" part in that statement. Most individuals in the non-academic world went to school at least partially to have better job prospects, perhaps even pursue a professional career like law or medicine. They certainly didn't go to school for the sake of going to school (right?). So when they hear "graduate student" I think some "working world" individuals think I went to school to go to more school, to avoid "working for Man" as it were. "If I'm in school I don't have to grow up and get a real job and be an adult, so why wouldn't I stay in school?" must be my line of reasoning.

Well, it isn't. Why I went to grad school will likely be a topic for another day, but I can say that avoiding "the Man" was not a large factor. Instead, I'll offer my insight to what a graduate student "does" in terms of it being a job (which it is). In some ways, it's like being an apprentice; you learn the in's and out's of research, what's going on in your field of study, and general professional conduct of being a professor/researcher/university teacher. For example, I'm currently writing my thesis, and it needs to include certain things and particular details. With this, I'm also reading up on current research and being exposed to what's happening in the field at the moment. I'm also a TA for a course in linear algebra, which involves marking tests and preparing tutorials each week for a section of around 75 students. Lastly, I engage with other students, professors and researchers on a regular basis to discuss other academic issues and research areas. These are typical duties of a grad student, and add up to a pretty involved "job". I also find time to have fun and prepare for a wedding in less than a year. I enjoy my current line of work, even with its downsides.

So in a nutshell, that's "what I do". What I'm going to "do" with this experience is obviously not as clear. I will likely be looking for work in the "real" world, and likely job positions are things like software developer, actuary, some kind of "analyst" or even teaching at either the high school or college level (university level is not looking good at this point for me). But those are just ideas, and I'm sure there are other things out there for me. Really I'd like a position that let's me do mathy stuff all day, so something quantitative. I'm also comfortable with computers and programming. However, I'll just have to see what I do with my Master's degree.

Greeting to the Digital World!

Hello everyone. I've decided to take a giant leap into the depths of Web, and put myself out there. Who knows, maybe someone will even pay some attention to me.

A bit about myself. I am Canadian, and currently completing a Master's Degree in Applied Mathematics at a southern Ontario university. I'm also engaged, and going to be married in a little under a year. Such opens the story of this blog. With these two things going on, I've been learning a lot of about the academic world, the "working" world, and the interaction between the two. I also really like mathematical biology, mon spécialité , and cooking, and my fiancee, among other things. This blog is about these things, and all other things that are, in a word, me.

Hopefully this will be good for me or someone else. If not, well, at least it's better than sitting around doing nothing (or baking too much...).