S282: Chapter 4 - Comparing Stars

This chapter is a major overdose on the Hertzsprung-Russell diagram. Its a popular diagram in astrophysics, and by the end of this chapter, and a few subsequent ones, you'll feel right at home with it. It looks at the location of the main sequence stars, like our Sun, which is towards the more insignificant end of the chart. Also at things like Red Giants, SuperGiants and white dwarfs which fall off the main bad somewhat.

You also pick up a few other lesser known types, such as Cephids, and T-Tauri stars, which turn out to be a bit more important later on.

After the H-R diagram has been done almost to death, the remainder of the chapter focuses on the interstellar medium and its affects on observations.

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S282: Chapter 3 - Measuring the stars

Chapter 3 is all about how the stars are analysed from the Earth. So here we meet all sorts of remote analysis techniques.
It starts with a look at how we can measure the distance to the stars, starting with measuring parallax. This allows distances to the nearer stars to be measured. It also discusses the proper motion of the stars, and also the radial and space velocity from these details.

Following that there is a look at how other things can be worked out. If you know the distance, you can work out the luminosity of the star. From this you can also work out things like radius, temperature and some other things. Spectroscopy features quite highly here, as there are a number of things that can be worked out from this. Radial velocity is one thing based on the Doppler shift. However there are a number of other things you can work out from this, including some clues to the mass and temperature.

This leads to the categorisation of stars into the stellar classes such as O,B,A,F,G,K,M etc.

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S320: TMA-1

Its time to face up to TMA-1 for this course. What is a level 3 TMA like?

Well firstly its a bit relentless. There are 7 questions in all, and most of them broken into sub parts.

Question 1 gives a table of data relating to bacterial infection rates. It gets you to do some simple statistics derived from these, such as working out case fatalities, and so on. It then gets you to write a few sentences on why the data may not be fully accurate. 18 marks for this part.

Question 2 is more simple, in that it is 12 marks to discuss three reasons why bacteria are likely to cause hospital acquired infections. This isn't too bad, except I struggle to find 12 worthwhile points in just a few sentences.

Question 3 looks at the disease syphilis, and the pathogen that causes it. The question ranges across the cause, change in incidence, and treatments for the disease. There are 22 marks available here, and again I struggle to find enough points to account for all the marks.

Question 4 covers Koch's postulates, and how it might be applied to the evidence that influenza might cause atherosclerosic plaques. 12 marks available here, but there seems precious little related information in the course book about this so I trawled through a number of papers..

Question 5 is a bit of a change. You are given a set of cases where the first sentence is true, and the second sentence may be true. You have to decide if the 2nd is, and if it is whether this is explained by the first statement. Another 12 marks here.

Question 6 is more descriptive asking why a knowledge of a pathogens biology might be useful in treating it. Another 12 marker.

Finally question 7 looks at viruses and what morphological changes there infection can cause.
Once again 12 marks.

I've spent quite some time on this TMA in fits and starts, but I'm struggling to pin down the connection between marks and salient points to make.

Oh well, its done now.

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S282: TMA-1

Time for the first TMA. As I flip through the pages, metaphorically as its actually delivered in PDF,my first though is it looks pretty long. Its got 5 questions, which doesn't sound that much, but it is. For instance the first question, has sub parts a), b) and c). Then part a) has sub-sub parts i) and ii), b) has i), ii) and iii) as does c). So that is 8 questions to be answered for 18 marks, in the first question alone, and a number of them are in the "explain why" category requiring more than just a number.

Question 1 (18 marks) is about black body and other radiation features such as peak wavelengths. Some calculation required, with a dose of explanation. .

Question 2 (25 marks) requires you to look at a photograph of the sun taken through a number of different filters and interpret the data. 4 sub questions, and 10 sub sub questions. Its about temperatures and emissions.

Question 3 (35 marks) you need to look at a sequence of photographs and do some work based on the images of what I think is a coronal mass ejection. This one requires calculation and a drawing to illustrate some features on the sun.

Question 4 (4 marks) is an exercise in using the planisphere to predict various starts rising and setting. You have to explain how you worked it out too.

Question 5 (18 marks) is about forward planning. TMA-2 requires one of two possible experiments to be done and this question leads you through explaining how you are going to run these experiments and when you are going to do it etc. Hopefully it is easy marks but is clearly designed to get you in the groove to run the experiment so there are no surprises.

Anyway - that's the first one down, and posted. Hope for the best!

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S320: Book 2 - Infectious Agents

On to book two. This looks at all things infectious. The work done in S204 is a good grounding for this, and there is some new information for me, but quite a bit is revision.
It looks at various infective agents (as the title implies)

• Bateria -types of bateria such as gram positive/negative. What makes them virulent, and what sort of infections they produce and a bit about combating them.
  
• Viruses -similar stuff to bacteria. It considers the various types of virus and how they work and what they do to you.
• Prions are next, and apart from a history and some general comments about BSE and so on there isn't a huge amount ot say about them.
• Then on to protoctist, what use to be protozoa and are also known as protoists. Basically mostly single cells eukaryotic cells that can infect.
• Fungi are next, considering things like thrush and athletes foot.
• Finally the bigger parasites, such as tapeworms and roundworms and the flukes.

So this book basically considers the range of things that cause infection and disease, with one or two rather yucky photographs included.

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S282: Chapter 2 - The working sun

This chapter moves from observation of the sun into the inner workings and how it all is thought to work, and what we can deduce. Things like models of the interior and how well they compare with measurements. Radiative and convection zones, stellar "earthquakes" and so on all feature.

Also covered are some of the reasons for the more visible things such as prominences and mass coronal ejections - which includes some tricky magnetic field stuff.

Finally the sunspot cycle and the 22 year general cycle.

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