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Marike defending her MSc thesis

29 March 2018

Marike defends her MSc thesis

It's another big day in the MeaseyLab as Marike Louw defends her MSc thesis:

Marike Louw has been with us since January 2016, and has made quite a splash in the lab. Marike worked extremely hard on a National Geographic funded project on aSCR. She trained many field assistants to set up acoustic arrays on the Cape peninsula. Marike won the CIB prize for the best MSc presentation at the ARM in 2016. In March 2017, Marike was runner up in a NRF science writing competition, and again in August 2017, she won a prize at the fynbos forum. She spent some of her prize money attending the BES meeting in Ghent, as well as presenting aSCR work in the ZSSA meeting in Pretoria. Marike attended our lab retreats (Kleinmond & Bonamanzi) and made a splash into the pool with her crazy synchronised swimming routines and appearing twice in the mannequin challenge. We've really enjoyed having you in the lab, and wish you all the best on your next mission to Marion Island!

From left to right, Carla, Damian celebrate with Marike & John

  aSCR  Frogs  Lab

How to write a hypothesis

28 March 2018

How to write a hypothesis

This is a sticking point for many students. We are used to using and writing questions and statements in day to day communications, as well as reading popular media. But hypotheses (the plural of hypothesis) only rarely float across our desks. So how do we write one, and how do we know if our hypothesis is good?

Although I’m going to write about what I think, there is already some good information out there on the web, and it’s worth looking at this too: (e.g. Wikihow, Wikipedia, etc.). There’s also some dodgy stuff, so read critically.

What is a hypothesis?

A hypothesis is a statement of your research intent. It tells the reader (because just like all of your other written work, it has an audience who reads it), what you planned to do in your research. But there’s a little more to it than this. The hypothesis becomes a part of the scientific method if it is testable, and informed from previous published work on the subject.

Yes, your hypothesis must  be informed by the literature, which is why you spent so much time and effort crafting your introduction to inform your reader of the same. This is also why your hypothesis usually comes at the end of your introduction, because you spend all of the introduction telling your reader about it (see blog entry here). There’s not much point in writing more after the hypothesis, because once your reader has read that, they are ready to learn about how you went about testing it (in the Materials & Methods). The other important point to make is that the literature should dictate how you write your hypothesis, and the variables that you include. If, for example, you know that temperature is the most important variable but all of the literature suggests that it is oxygen, you can’t ignore oxygen and you should also frame your hypothesis using this variable (you can have more than one hypothesis after all!). In this case, you will also need to provide a sufficient introduction to temperature as a variable to justify its inclusion in your hypothesis. Perversely, your aim is not to prove that your idea is right, but to show that the hypothesis is wrong.

We usually try to write a hypothesis that is falsifiable: i.e. you can prove (usually using statistical tests) that it is not correct (or at least show that the likelihood that it is correct is very low). That’s why it is conventional to provide the ‘Null hypothesis’ that is the falsified version of the statement, suggesting that there is no relationship between the variables you have proposed to measure. The convention is to label this H0, while the ‘alternative hypothesis’ (the one that says your variables are related as you suggested) is written as H1. You can write you alternative hypothesis to show the directionality of your tested variables, or simply that there is a relationship.

Most importantly, your hypothesis must come first, before you do the experiment or study! Setting the hypothesis after the work is already done is fraudulent, and goes against the scientific method. Obviously, it isn’t fair to pose the hypothesis once you already know the answer. This is why there is so much emphasis put on formulating your hypothesis during your research proposal. Getting it right will determine what you do and how you test it. If you think of an extra hypothesis that would be really useful to test once you’ve already done your study, you can conduct a post hoc test, but this should have more stringent levels of statistical assessment.

Writing a hypothesis isn’t easy, but it is essential and once you’ve understood what to do, most of the rest of what you are writing for should make sense.

What a hypothesis isn’t

It is not a question and so should never have a question mark after it.

It isn’t really a simple prediction: if this then that. You will see many times on the internet that hypotheses are explained in this simple predictive framework. I say that it isn't 'really' a simple prediction because these are not good hypotheses. They lack the mechanistic and scholarly aspect of a good hypothesis, which is what we want to achieve.

A formulaic way to start writing your hypothesis:If… then… because…

Above, I emphasised that you must have introduced all the variables that you plan to use to test your hypothesis in your introduction. This usually comes in the second paragraph (see blog entry here), where you emphasise the utility of the dependent variable/s (what you are planning to measure) and your independent variable (what you will manipulate). Both of these variables should then feature in your hypothesis. Next, by paragraph four you will have identified the problem that you are interested in tackling. In addition, your introduction will provide all of the pertinent literature that has relevance to this hypothesis, giving the all important context.

A simple way to consider making your hypothesis is to adopt an “If… then… because…” construction where you add in your problem statement using your independent variable after ‘if’ and your prediction using your dependent variable after ‘then’, and finally the expected mechanism after ‘because’. Using our example above with the “If… then… because…” construction, we would say: “If environmental temperatures in which tadpoles develop are increased then tadpole development rate is faster because they follow the classic metabolism of ectotherms”. Both independent variable (temperature) and dependent variable (tadpole development rate) are present in this hypothesis, and the predicted relationship between them is clear. In addition, the causal mechanism is stated. You can watch a video about using the “If… then… because…” construction here, or read more here. I say that this is a formulaic way to start writing your hypothesis, because it usually ends up as an inelegant statement, which can be better refined for a reader. A citation for your stated mechanism might also help clarify exactly where the justification for this comes from.

A good hypothesis will often take an existing hypothesis further, to try to better refine the knowledge on a subject. Hence, it is perfectly acceptable to state that you are building on existing hypotheses (and giving the appropriate statement) when making your own.

How to evaluate your hypothesis

Once you’ve written your hypothesis, how do you decide whether or not it is good? To do this, you might think that you need plenty of experience (and yes, that does help). But really, you just need to look for the elements that are discussed above. So once you’ve written your hypothesis, try to objectively answer the questions below (for more see Bartos 1992 and here):

  1. Is there a clear prediction (if… then… statement)?
  2. Does the prediction use independent and dependent variables correctly?
  3. Is the mechanism supported by the literature?
  4. Is the hypothesis testable/falsifiable?
  5. Does the hypothesis use concise wording and precise terminology?

If your hypothesis meets all of the criteria above, then you’ve done a good job!

  Lab  Writing

Theses submission

19 March 2018

Magic March for thesis submission

A big congratulations to Mac and Marike for submitting their theses this March.

 

Mac’s PhD thesis “Evaluating the effects of changing global climate on amphibian functional groups of southern Africa: an ecophysiology modelling approach” uses performance, morphology, physiology and modelling to predict species distributions in southern Africa.

Marike’s MSc thesis “Acoustic Spatial Capture-Recapture (aSCR) and the Cryptic Cape Peninsula Moss Frog Arthroleptella lightfooti” uses the aSCR technique to determine population density with many acoustic arrays.

Well done to you both! Very fine pieces of work indeed.

  aSCR  Frogs  Lab  Xenopus

Making a presentation from your research proposal

18 March 2018

Making a presentation from your research proposal

In theory, it couldn’t be easier to take your written research proposal and turn it into a presentation. Many people find presenting ideas easier than writing about them as writing is inherently difficult. On the other hand, standing up in front of a room of strangers, or worse those you know, is also a bewildering task. Essentially, you have a story to tell, but does not mean you are story telling. It means that your presentation will require you to talk continuously for your alloted period of time, and that the sentences must follow on from each other in a logical narative; i.e. a story.  

So where do you start?

Here are some simple rules to help guide you to build your presentation:

  1. One slide per minute: However many minutes you have to present, that’s your total number of slides. Don’t be tempted to slip in more.
  2. Keep the format clear: There are lots of templates available to use, but you’d do best to keep your presentation very clean and simple.
  3. Be careful with animations: You can build your slide with animations (by adding images, words or graphics). But do not flash, bounce, rotate or roll. No animated little clipart characters. No goofy cartoons – they’ll be too small for the audience to read. No sounds (unless you are talking about sounds). Your audience has seen it all before, and that’s not what they’ve come for. They have come to hear about your research proposal.
  4. Don’t be a comedian: Everyone appreciates that occasional light-hearted comment, but it is not stand-up. If you feel that you must make a joke, make only one and be ready to push on when no-one reacts. Sarcasm simply won’t be understood by the majority of your audience, so don’t bother: unless you’re a witless Brit who can’t string three or more sentences together without.

Keep to your written proposal formula

  1. You need a title slide (with your name, that of your advisor & institution)
  2. Several slides of introduction
    1. that put your study into the big picture
    2. explain variables in the context of existing literature
    3. explain the relevance of your study organisms
    4. give the context of your own study
  3. Your aims & hypotheses
  4. Methods & Materials
    1. Images of apparatus or diagrams of how apparatus are supposed to work. If you can’t find anything, draw it simply yourself.
    2. Your methods can be abbreviated. For example, you can tell the audience that you will measure your organism, but you don’t need to provide a slide of the callipers or balance (unless these are the major measurements you need).
    3. Analyses are important. Make sure that you understand how they work, otherwise you won’t be able to present them to others. Importantly, explain where each of the variables that you introduced, and explained how to measure, fit into the analyses. There shouldn’t be anything new or unexpected that pops up here.
  5. Expected results
    1. I like to see what the results might look like, even if you have to draw graphs with your own lines on it. Use arrows to show predictions under different assumptions.
  6. Budget
  7. Timeline

Slide layout

  1. Your aim is to have your audience listen to you, and only look at the slides when you indicate their relevance. 
  2. You’d be better off having a presentation without words, then your audience will listen instead of trying to read. As long as they are reading, they aren't listening. Really try to limit the words you have on any single slide (<30). Don’t have full sentences, but write just enough to remind you of what to say and so that your audience can follow when you are moving from point to point.
  3. Use bullet pointed lists if you have several points to make (Font 28 pt)
  4. If you only have words on a slide, then add a picture that will help illustrate your point. This is especially useful to illustrate your organism. At the same time, don’t have anything on a slide that has no meaning or relevance. Make sure that any illustration is large enough for your audience to see and understand what it is that you are trying to show.
  5. Everything on your slide must be mentioned in your presentation, so remove anything that becomes irrelevant to your story when you practice.
  6. Tables: you are unlikely to have large complex tables in a presentation, but presenting raw data or small words in a table is a way to lose your audience. Make your point in another way.
  7. Use citations (these can go in smaller font 20 pt). I like to cut out the title & authors of the paper from the pdf and show it on the slide.
  8. If you can, have some banner that states where you are in your presentation (e.g. Methods, or 5 of 13). It helps members of the audience who might have been daydreaming.

Practice, practice, practice

  1. It can’t be said enough that you must practice your presentation. Do it in front of a mirror in your bathroom. In front of your friends. It's the best way of making sure you'll do a good job.
  2. If you can't remember what you need to say, write flash cards with prompts. Include the text on your slide and expand. When you learn what’s on the cards, relate it to what’s on the slide so that you can look at the slides and get enough hints on what to say. Don’t bring flashcards with you to your talk. Instead be confident enough that you know them front to back and back to front.
  3. Practice with a pointer and slide advancer (or whatever you will use in the presentation). You should be pointing out to your audience what you have on your slides; use the pointer to do this.
  4. Avoid taking anything with you that you might fiddle with.



  Lab  Writing

OTS back at Cape Point

04 March 2018

Great to join OTS at Cape of Good Hope

Another opportunity to monitor the Cape platanna (Xenopus gilli) at the Cape of Good Hope section of Table Mountain National Park. This time with a great crew from Organisation for Tropical Studies (OTS). I was last with OTS in October (see here), and before that in February and see blog entry herehere and here!

This time we had a delayed start as part of CoGH burned down on Thursday (1st May), but the area across link road and Olifantsbos didn't include our frogging patch (more's the pity). 

The focus was on the drought, with GEPS dam as low as I've ever seen it, but still with hundreds of frogs inside.

  Frogs  Xenopus