If like us you are a member of the AAGBI then you will recently have received a copy of their latest glossy on Red Cell Transfusion. Sadly they don't appear to have put it up on their website yer, and we've not had time to review it, but we will try to keep an eye on the website and put up a link as soon as we can.
Keep an eye on the site as we get closer to the closing date for entry and we will put up a list of what we consider are likely to be the hot topics from the previous 12 months. Also, watch James Shorthouse's blog over at Passing the Final, as he keeps a good update going, which often includes the hot topics.
Showing posts with label revising. Show all posts
Showing posts with label revising. Show all posts
Monday, 14 July 2008
Monday, 7 July 2008
Usually drink, usually dance, usually bubble
EI has relations with a Street Style blog over at Stitsh.com, and recently a little vid caught our attention over there. Click here and scroll down to 28.06.08.
It reminded us of a little law that the examiners sometimes like to question, that is Henry's Law:
At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.
Okay, so what does that mean.
Most of the time we refer to Henry's law by the formula p=kc (that's one way of looking at it - Ed).
Another way is to say:
The pressure above a solution dictates how many collisions occur between the gas and the liquid. So if you increase the pressure above the solution, the partial pressure of the gas increases, the number of collisions increases, and more gas is dissolved. What will then happen is that an equillibrium will be achieved, where the number of molecules of gas crashing into the surface of the liquid will be the same as the number of molecules leaving the surface of the liquid.
The more observant amongst you will have realised that temperature hasn't been mentioned yet except in the definition....
So what effect does temperature have?
Well, think of a can of "fizzy pop" (you're showing your age there - Ed). When it comes out of the fridge, it's not that fizzy, is it? However, the longer you leave it standing around, the closer it's temperature comes to room temperature, and then when you go back to the can, first it will seem quite gassy, and then eventually it will go flat. This is because the gas in the drink is coming out of solution. The gas solubility relationship with temperature is very similar to the reason that vapor pressure increases with temperature. (This is Gay-Lussac's Law: The pressure of a given number of moles (given amount) of gas, is directly proportional to its temperature in Kelvin (absolute temperature scale), when the volume is kept constant. Better known as P/T=k).
Increased temperature causes an increase in kinetic energy, which in a gas causes either expansion or an increase in pressure, or in this instance, more movement of the molecules, which break free of the surface of the solution! (The surface could be the gas side of a small bubble of gas trapped within the solution, which is one reason we get bubbles!)
If you want to see another demonstration of Henry's law in action, look at a pan of water. As you warm the pan, small bubbles start to form, well before the pan reaches 100°C (373K). Those bubbles are air coming out of solution.
So why do the examiners like this concept: the Bends.
Decompression Sickness occurs when gas (specifically nitrogen) is breathed at higher than atmospheric pressure, and the diver then returns to atmospheric pressure without allowing the gas to come out of solution slowly, resulting in gas bubble formation, and hence, "the bends" (gas in the joints) and "the staggers" (gas bubbles in the brain causing confusion and ataxia) and "the chokes" (probably PE).
It is also a concept that comes into play when talking about Ostwald and Bunsen coefficients....(more on that another time).
(Equations courtesy of Wikipedia)
It reminded us of a little law that the examiners sometimes like to question, that is Henry's Law:
At a constant temperature, the amount of a given gas dissolved in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.
Okay, so what does that mean.
Most of the time we refer to Henry's law by the formula p=kc (that's one way of looking at it - Ed).
Another way is to say:
where:
is approximately 2.718, the base of the natural logarithm
is the partial pressure of the solute (the gas being dissolved) above the liquid in which is being dissolved.
is the concentration of the solute in the solution
is the Henry's Law constant, which has units such as L·atm/mol, atm/(mol fraction) or Pa·m3/mol (this is so that the dimensions all work out correctly - the funny thing about constants is that they usually can be expressed in many different units, depending on what units the rest of the equation is being calculated in....more on that another time).
The pressure above a solution dictates how many collisions occur between the gas and the liquid. So if you increase the pressure above the solution, the partial pressure of the gas increases, the number of collisions increases, and more gas is dissolved. What will then happen is that an equillibrium will be achieved, where the number of molecules of gas crashing into the surface of the liquid will be the same as the number of molecules leaving the surface of the liquid.
The more observant amongst you will have realised that temperature hasn't been mentioned yet except in the definition....
So what effect does temperature have?
Well, think of a can of "fizzy pop" (you're showing your age there - Ed). When it comes out of the fridge, it's not that fizzy, is it? However, the longer you leave it standing around, the closer it's temperature comes to room temperature, and then when you go back to the can, first it will seem quite gassy, and then eventually it will go flat. This is because the gas in the drink is coming out of solution. The gas solubility relationship with temperature is very similar to the reason that vapor pressure increases with temperature. (This is Gay-Lussac's Law: The pressure of a given number of moles (given amount) of gas, is directly proportional to its temperature in Kelvin (absolute temperature scale), when the volume is kept constant. Better known as P/T=k).
Increased temperature causes an increase in kinetic energy, which in a gas causes either expansion or an increase in pressure, or in this instance, more movement of the molecules, which break free of the surface of the solution! (The surface could be the gas side of a small bubble of gas trapped within the solution, which is one reason we get bubbles!)
If you want to see another demonstration of Henry's law in action, look at a pan of water. As you warm the pan, small bubbles start to form, well before the pan reaches 100°C (373K). Those bubbles are air coming out of solution.
So why do the examiners like this concept: the Bends.
Decompression Sickness occurs when gas (specifically nitrogen) is breathed at higher than atmospheric pressure, and the diver then returns to atmospheric pressure without allowing the gas to come out of solution slowly, resulting in gas bubble formation, and hence, "the bends" (gas in the joints) and "the staggers" (gas bubbles in the brain causing confusion and ataxia) and "the chokes" (probably PE).
It is also a concept that comes into play when talking about Ostwald and Bunsen coefficients....(more on that another time).
(Equations courtesy of Wikipedia)
Monday, 30 June 2008
Course Study
Are you about to embark on an expensive course to try and help you pass the final?
You've hoarded your study leave, swapped your nights into doing 7 nights in a row, left your significant other and shipped yourself off for a week in strange parts of the country you've never seen and never will again?
Or you've managed to escape the humdrum day to day work of the operating room to get yourself onto a day release course?
Well, here's a tip.
Don't take any notes.
Okay, perhaps that's a little exaggeration. Let me go into more detail.
EI previously noted the potential for Mind Maps in another post, and described how to use those. Here's another cunning ploy. Use only essential keywords. Take your mindmaps to the next level and only write down a few really key central points during the lecture, and focus your entire mind on what the speaker is saying. Even better: interact with the speaker (this will give your brain an extra "hook" to hang the lecture on.
Instead of keeping a record of the lecture on paper, use a dictaphone
to record the lecture. From the recording, using very simple software, almost always already on your computer, you can transfer the file from the dictaphone to an MP3 file which any player can play back. You can then take a look at your keywords document whilst you're eating breakfast in the morning, and listen to the lecture on the train/bus/walking/car journey to work, when you come to revise.
Robert Whitaker over at InstantAnatomy.net has some excellent podcasts and audiovisual lectures on his CD, which you can use as an example (though his AV presentations are much more detailed than your notes ought to be). These were staple listening in the run up to the exam (MCQ/SAQ and the vivas).
You might think that this won't work for things like physiology/pharmacology etc, but you'd be surprised at how effective it can be. Try just jotting down graphs without the masses of detail, or the drug molecules off the board. Don't write down every single point, because that's where you get distracted. Give it a try....
You've hoarded your study leave, swapped your nights into doing 7 nights in a row, left your significant other and shipped yourself off for a week in strange parts of the country you've never seen and never will again?
Or you've managed to escape the humdrum day to day work of the operating room to get yourself onto a day release course?
Well, here's a tip.
Don't take any notes.
Okay, perhaps that's a little exaggeration. Let me go into more detail.
EI previously noted the potential for Mind Maps in another post, and described how to use those. Here's another cunning ploy. Use only essential keywords. Take your mindmaps to the next level and only write down a few really key central points during the lecture, and focus your entire mind on what the speaker is saying. Even better: interact with the speaker (this will give your brain an extra "hook" to hang the lecture on.
Instead of keeping a record of the lecture on paper, use a dictaphone
to record the lecture. From the recording, using very simple software, almost always already on your computer, you can transfer the file from the dictaphone to an MP3 file which any player can play back. You can then take a look at your keywords document whilst you're eating breakfast in the morning, and listen to the lecture on the train/bus/walking/car journey to work, when you come to revise.Robert Whitaker over at InstantAnatomy.net has some excellent podcasts and audiovisual lectures on his CD, which you can use as an example (though his AV presentations are much more detailed than your notes ought to be). These were staple listening in the run up to the exam (MCQ/SAQ and the vivas).
You might think that this won't work for things like physiology/pharmacology etc, but you'd be surprised at how effective it can be. Try just jotting down graphs without the masses of detail, or the drug molecules off the board. Don't write down every single point, because that's where you get distracted. Give it a try....
Wednesday, 4 June 2008
A little study tip time...
I'm afraid I don't have any magic answers on how to succeed in the exam, other than, "Study Hard", "Practice Often" and "Study Some More".
The thing is, that "Studying" is one of those ill-defined things that I say "I'm going to study", but actually I'm not sure what I mean, and that's what's held me back, I think, from getting on with some proper work.
Now I hate "drawing up a studying plan" (or "study plan", if you like), and I've never done that. What I do, however, is decide what it is I hope to learn by the end of my session of "studying", whatever length of time that may be.
This morning I decided I was going to learn about principles of anaesthetising patients with cardiovascular disease, including hypertension, abnormal ECGs, valve disease, and congenital heart disease. That sounds like a big topic, and it is in some ways. However, by grouping it all together under the "Cardiovascular Diseases" heading, and not spreading them out over a few days, I felt I was better able to integrate the information. Whether it's gone in for good or not is another question!
Let me explain a bit more: because I had in my mind to learn about CVS disease and the impact on anaesthesia/anaesthetic technique, I had a peg to hang things on. If I then read about some CVS, some renal, some hepatic, and then came back tomorrow to read about some more CVS, it would be kind of jumbled up. Comprende? Instead, because I read all about it in one go, I was able to take ideas from one bit and integrate them with another bit and it all makes (more) sense.
Anyway, that's what I mostly do, try and have an idea of what it is I want to learn by the end of the session, rather than generically "learning something, anything!"
I did spend about one and a half hours with one of my friends doing some viva voce practice, but I can't say I felt very positive at the end of it. I would like to excuse myself by saying I have just finished 5 nights, but that doesn't really make me feel much better.....
The thing is, that "Studying" is one of those ill-defined things that I say "I'm going to study", but actually I'm not sure what I mean, and that's what's held me back, I think, from getting on with some proper work.
Now I hate "drawing up a studying plan" (or "study plan", if you like), and I've never done that. What I do, however, is decide what it is I hope to learn by the end of my session of "studying", whatever length of time that may be.
This morning I decided I was going to learn about principles of anaesthetising patients with cardiovascular disease, including hypertension, abnormal ECGs, valve disease, and congenital heart disease. That sounds like a big topic, and it is in some ways. However, by grouping it all together under the "Cardiovascular Diseases" heading, and not spreading them out over a few days, I felt I was better able to integrate the information. Whether it's gone in for good or not is another question!
Let me explain a bit more: because I had in my mind to learn about CVS disease and the impact on anaesthesia/anaesthetic technique, I had a peg to hang things on. If I then read about some CVS, some renal, some hepatic, and then came back tomorrow to read about some more CVS, it would be kind of jumbled up. Comprende? Instead, because I read all about it in one go, I was able to take ideas from one bit and integrate them with another bit and it all makes (more) sense.
Anyway, that's what I mostly do, try and have an idea of what it is I want to learn by the end of the session, rather than generically "learning something, anything!"
I did spend about one and a half hours with one of my friends doing some viva voce practice, but I can't say I felt very positive at the end of it. I would like to excuse myself by saying I have just finished 5 nights, but that doesn't really make me feel much better.....
Subscribe to:
Posts (Atom)
