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Archive January 2010

of rain and rotifers Alison Campbell Jan 31

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Yesterday we went across to Tauranga to see my in-laws. It was a terrible day for driving; the forecast was for periods of heavy rain & it was pouring down when we arrived. My father-in-law had emptied the rain gauge that morning (23mm, he said), & by 1pm it was back up to 80mm & rising. There was a lot of surface flooding on the road coming home, the roadside drains had turned to foaming brown torrents, and many paddocks were more like pools, with cattle standing close to hedges to avoid at least some of the driving rain.

And seeing those pools my thoughts turned (as they do) – to rotifers.

Rotifers are rather cool little microscopic animals. Each rotifer has less than 1000 cells in their tiny body, and some of them are smaller than single-celled protozoa. They’re found in fresh water just about everywhere (although there are some marine species as well) & will quickly colonise temporary ponds. (Hence the drift of my thoughts.) If you look at some of the rotifer images here you’ll see that while their shapes may differ they all have one feature in common: a crown of beating cilia at one end of that small rounded body. The name ‘rotifer’ reflects the fact that in many rotifers – the bdelloid rotifers - the beating cilia give the impression of a rapidly spinning rotor, or wheel.

I talk a bit about these fascinating wee animals in some of my lectures, on account of their reproductive habits. Why? Because many species (& all of the bdelloid rotifers) reproduce asexually, & have done so for a very long time indeed. "No sex for 30 million years" announced the headline of a rotifer story in our local paper – unfortunately this headline sat next to a photo of the researcher studying them… (My colleague had to put up with a bit of teasing & the journalist concerned was mortified, muttering at length about the iniquitous sub-editor who’d thought up that little gem!)

There’s only one gender in the bdelloid rotifers, & that’s female. Lacking males, they reproduce by parthenogenesis. Each female produces what are known as amictic eggs, which develop without fertilisation to produce daughters that are effectively clones of their mother. Because every individual in the population is capable of producing offspring, such populations can grow in size very rapidly.

Other species have the best of both worlds, combining parthenogenesis & sexual reproduction in quite a complex cycle. A female can produce 2 types of eggs that both develop parthenogenetically – one into females & the other into males, followed by a round of sexual reproduction. Apparently the latter type is produced in response to a change in the environment. This makes a lot of sense, in evolutionary terms. While the environment is relatively constant, producing offspring that are all clones of the parent means that they’ll all be fairly well-adapted to that environment (otherwise, the original ‘mother’ rotifer wouldn’t have survived in the first place). But a changed environment may place different demands on the organism. Producing males in response to such a change allows for genetic recombination, producing a range of individuals some of which may be able to survive in their new situation.

Speaking of changed situations – I was intrigued to discover that bdelloid rotifers can also enter a state called ‘anhydrobiosis’: their tissues dehydrate & in this condition they can survive for some considerable time until rehydrated again (eg after heavy rainfall refills temporary ponds). This is a relatively common strategy, but my favourite anhydrobiotic organism has to be the water bear :-)

I say ... you wouldn't be in receipt of some sort of picnic basket would you?

This image is of a normal, fully hydrated water bear, or tardigrade. As the name suggest, these cute little critters live in fresh water, crawling around on plants. But in the fully dessicated, anhydrotic state they’d win any survival contest, I think: they can cope with being frozen to around -273oC or heated to more than 100oC, exposed to pressures equivalent to 6000 atmospheres or to high doses of radiation, or even the vacuum of space. And then they’ll bounce back to their normal cuddly state on rehydration. The ultimate Survivor of the animal kingdom, methinks.

avatar Alison Campbell Jan 29

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The family finally got its act together & went to see Avatar. In 3D :-) (Actually our act was arranged by friends, who also organised us into an al fresco meal of fish’n'chips beforehand.) I carefully didn’t read anything much about the movie before I went, so I’m aware that what I’ve got to say has probably been said before - but here goes, anyway.  

Wow!

Just, wow!!!

Visually that has to be the most stunning thing I have ever seen in a movie theatre, by a country mile. OK, the story-line was pretty basic & the ending was signalled well beforehand… And the 3D glasses left a dent in my nose… But the way in which the world of Pandora & its ecosystems was rendered was wonderfully and beautifully done. (My friends & I agreed that parts of it were reminiscent of the record cover art of Roger Dean.) And I can see why ecologists like my colleague Bruce Clarkson are so taken with it, & its overtones of the Gaia hypothesis. And as a zoologist-by-training I was enthralled by the Pandoran animals.

But. (There’s always a ‘but’, isn’t there?) That same training also left me with a few questions at the end. And they had to do with the place of the Na’vi in their world. What I mean is, in evolutionary terms, they don’t belong. If they had evolved on Pandora, then it would have been from one of the other animal life-forms. All of which seemed to have 6 legs (2 pairs of forelimbs), 2 pairs of eyes, and nostrils pretty much in their armpits. Which is all great & made them convincingly alien. So – whence the Na’vi, with their very humanoid appearance & the ‘right’ number of eyes & nostrils? In other words, while the Pandoran environment looks great, the evolutionary back-story was a leetle shaky :-)

Didn’t stop me really enjoying the experience, though! (And yes, I am a pedantic science geek!)

_________________________________________________________________________________

& now I see that, in the way of the world, I’m by no means the first to see the apparent derivation from Dean’s work. Or think about the zoology (Tetrapod Zoology has a lovely take on this) Or quibble about the evolutionary ‘science’. But we all enjoyed the film :-)

a quick lesson from statistics :-) Alison Campbell Jan 25

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Frm PHD Comics (via Pharyngula):

 

I couldn’t agree more :-)

mms revisited Alison Campbell Jan 24

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A while ago I wrote a post on the so-called ‘miracle mineral supplement’, aka MMS. I thought I’d re-post it following an article debunking this nostrum in the Sunday Star-Times. My original post attracted a couple of comments from people claiming that MMS will cure a multitude of ills; I’ve reproduced them, & my responses, after the re-post.

After reading & commenting on that letter, which attributed health benefits to sodium chlorite, I found my interest had been piqued. Just what has been claimed for this chemical? So I went looking…

 

… & found, among other things, a webpage claiming all sorts of things for this ‘miracle mineral supplement’.

Apparently it’s not the sodium chlorite itself, but the chlorine dioxide that is produced from it in slightly acidic solution. The acetic acid in vinegar is supposedly ideal as an acidifier, act[ing] like a blasting cap by lowering the pH of the chlorine dioxide without setting it off. Then – you drink it! (Although in miniscule quantities – 6-15 drops in a glass of water… Not quite a homeopathic concentration, then.)

This is where things get interesting, from a chemical & biological point of view. When a chlorine dioxide ion contacts a harmful pathogen, it instantly rips up to five electrons from the pathogen, in what can be likened to a microscopic explosion… harmless to us, but terminal to pathogens. The pathogen – an electron donor – is rendered harmless due to the involuntary surrendering of its electrons to the chlorine dioxide – an electron acceptor – and the resulting release of energy. Oxidised by the chlorine ion, the former pathogen becomes a harmless salt.

Hmmm. “Pathogen” = ‘an agent that causes disease, especially a living microorganism such as a bacterium or fungus.’ Now, chloride dioxide gas is used in killing bacteria on food – but this is in relatively high concentrations & a far cry indeed from killing bacteria/fungi within the body. (The belief that it can be used in this way sounds similar to the belief that if colloidal silver in an ointment on your skin will kill bacteria, how much better it will be for you if you drink the stuff. At least with ClO2, I guess you’re not likely to turn blue…) But it’s not nice stuff: If you were to breathe air containing chlorine dioxide gas, you might experience irritation in your nose, throat, and lungs. If you were to eat or drink large amounts of chlorine dioxide or chlorite, you might experience irritation in the mouth, esophagus, or stomach.

Also – I really want to know – how would the ClO2 distinguish between a pathogen, & normal body cells? According to the site’s author, ‘toxic’ or ‘diseased’ body cells are more acidic than normal cells, & this underlies the ClO2 effect. A pity, then, that normal cells, happily respiring away, also acidify their surroundings as they release carbon dioxide – a necessary effect that triggers release of oxygen from the haemoglobin in circulating red blood cells (the Bohr effect), thus allowing the cells to continue respiring. Can the ‘miracle mineral supplement’ tell the difference here? And how does it get round the body, anyway?

Apparently by being picked up by the red blood cells, instead of oxygen… Red blood cells … do not differentiate between chlorine dioxide & oxygen. Therefore, [after you've drunk the sodium chlorite solution], red blood cells pick up chlorine dioxide ions that are deposited on the stomach wall where it normally gathers nutrients of various kinds before journeying through the body. Then, when the red blood cells armed with chlorine dioxide encounter parasites, fungi, or diseased cells that all have low pH and a positive ionic charge, the ‘aliens’ are destroyed along with the chlorine dioxide ion.

Hmm. Chlorine dioxide is certainly used as a sterilising agent for red blood cells. But in high enough quantities it can markedly reduce your blood’s ability to carry oxygen – hardly a Good Thing. Just as well, then, that the stuff isn’t all that likely to enter the bloodstream, given that it’s supposed to be taken in miniscule quantities & that the odds of it being picked up by red blood cells is vanishingly small. Far more likely that it will be consumed by some other redox reaction in the gut.(Oxygen saturation of haemoglobin is usually around 98%, so there isn’t much spare capacity there.)

And, of course, your body already has a perfectly good way of dealing with parasites, fungi, & so on – it’s called an immune system :-)_______________________________________________________________________________

The comments:

I am a Medical Laboratory Scientist, and I am surprised at your attitude. Your theorising about MMS, without backing it up with your own personal experience, is unscientific to say the least.
From what I can gather, you are quite prepared to dismiss MMS… even as a last resort. I am not surprised though. Your apparent indoctrination by allopathy is akin to religious intolerance.
Allopathy kills thousands of New Zealanders each year with ineffective toxic drugs. Iatrogenesis is ignored. Sooner or later the public will discover the widespead scams of the medical industry. Then the penny will drop and how will they explain their failures?
I have some advise for you. Have an open mind about MMS, try it yourself and don’t pre judge.

My ‘own personal experience’ would amount to no more than anecdote. Anecdote = data, so it would in fact be unscientific to base my statements on personal experience. There is no scientific underpinning to the claims made for MMS & its proposed mode of action is improbable in the extreme.

I would have to agree with Emanuel’s previous comment. Don’t draw conclusions from what you read;…try it first.
I have personally used MMS for a couple of years now and have had great results.
I have recommended it to many others, and know of people completely cured of cancer (among many other things), using only MMS; no other treatments. One was a lady with a 6cm pancreas cancer tumor, sent home to die. Two months on, her daughter tells me she is completely cured. Another friend of a friend cured himself of prostrate cancer using only MMS. I have a cousin currently trying it for a brain tumor. Although(to my knowledge), no-one seems to have carried out ‘approved clinical trials’ on this product; positive reports are poping up around the world.
The point is, results speak louder than the closed minded, bias opinions that you will find pasted all over the internet.
I hope you will give it a try before you speak any further negative words about this amazing product. It is available from www.miraclemineral.co.nz if you want to test it for yourself,

The problem here, though, is that we’re dealing with anecdotes rather than actual data. For example, was the friend of your friend formally diagnosed with prostate cancer, or was it a self-diagnosis? If the latter, then the ‘cure’ may not be what it first appears. Similarly, where is the medical diagnosis of a complete cure for a pancreatic tumour? (Hearsay evidence isn’t sufficient.)
In addition, there is no mechanism by which MMS does what is claimed for it – basic chemistry & physics mean that it cannot act as described on many of the websites promoting its use.
If it does have an effect for some people then we are almost certainly looking at the placebo effect. Which would mean MMS wouldn’t work to me, as I wouldn’t expect it to :-) And the big worry with the placebo effect is that it may simply mask underlying conditions, rather than making them go away…

asking the right questions Alison Campbell Jan 20

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A colleague sent me advance notice of an upcoming protest: a ‘mass overdose’ of sugar pills being organised as a protest against ‘homeopathic remedies’. (Grant picked up on this & has blogged on it over at SciBlogs. This got me thinking (as these things do) about an interesting podcast by Mark Crislip, who focuses on supplements & ‘complementary & alternative medicines’. This particular episode concerned claims that a particular food, supplement or treatment ‘boosts the immune system’. There are a few questions you should ask when you hear such statements.

How does it boost the immune system? Your immune system has a number of inherent control mechanisms that regulate its responses. Which of these mechanisms does the food/supplement/treatment affect, and how?

Which part of the immune system does it target? After all, the mammalian immune system is a thing of many parts: non-specific & specific responses; cellular & ‘humoral’ components (eg antibodies); the many different types of white blood cells; signalling & regulatory chemicals such as cytokines, interleukins, & interferons… – which of these, specifically, does the food/supplement/treatment target?

What is the evidence in support of these claims? Is it based on ‘in vitro’ studies ie of cells that have been isolated from the system & grown & studied in the test tube? These aren’t necessarily going to behave as they would in the actual organism. (I’m reminded of a study I read some years ago now, that supposedly demonstrated that drinking chicken soup really was a good thing to do when you’re sick. But it didn’t look at the impact on patient health of drinking chicken soup – the researchers looked at the effect of samples of soup on the activity of isolated white blood cells: specifically, whether or not it inhibited the cells’ abiltiy to generate an inflammatory response. But this doesn’t mean it will translate to a similar effect in the body.) In fact, it turns out that white blood cells will often generate an ‘inflammatory response’ in the presence of some pathogens, but this doesn’t necessarily translate into an elevated body-wide immune response.

And that segues nicely into the final question: Is ‘boosting the immune system’ necessarily a good thing? If that response is a generalised inflammatory response, the answer is, quite possibly not. Because chronic inflammatory responses may be related to increased risk of blood clots, and those in turn can carry nasty health risks. For example, a 2006 study published in the Lancet found that people who’d had a urinary tract infection, with accompanying inflammatory response, had a heightened risk of developing a thrombosis (blood clot) in the four weeks immediately after the infection. There are similar findings from other studies. This apparent inflammation-thrombosis link hasn’t yet been shown to be a causal relationship, & we do need to be careful in attributing causality (it’s all too easy to get it wrong NB warning, this is humour!), but it’s certainly one to consider.

In fact, in people who are in good health & do all the common-sense things needed to stay that way (ie get sufficient sleep, exercise, & food), it’s neither necessary nor possible to ‘boost’ the activity of their immune systems. It’ll work just fine all by itself :-)

communicating science – an example of good practice Alison Campbell Jan 18

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The following is from the Young Australian Skeptics website – I’ve copied the whole post across because it’s a brief one (& I’ve added links to book reviews):

We probably have all encountered scientifically ignorant people, for some people knowing the complexities of the universe is simply not interesting. This ignorance is generally spawned within the Medias interpretation of science and scientists; however a scientist known as Len Fisher is doing something about this by communicating science to the general community. Earlier in Brisbane  this year (as part of the BrisScience and BWF Festival) he held a seminar on how science should be communicated to the public. Len Fisher is best known for his ignoble prize for physics; it related to the topic why biscuits go soggy when you dip them in your tea.

He was contacted by a biscuit company to conduct this research, much to the derision of his colleagues; however his aim was to show to the media how real scientists think about everyday problems. He made it very clear to the reporters that the research was not really “life or death” serious research but it was to illustrate that science is not just a collections of immaterial facts and figures, but the study of reality. This was also seen in his desire for the motto and aim of the ignoble prize completion to be changed; it was originally an award for “Science that should not and cannot be reproduced”, he morphed this to “Science that first makes you laugh, then makes you think”.

This aim was to elevate respect for science within the community and to inspire interest in education. Len fisher has also authored several novels on a variety of topics: Rock, Paper and Scissors: Game Theory in everyday life, How to dunk a doughnut: The science of everyday life, Weighing the soul: The evolution of Scientific ideas, The perfect swarm: The science of Complexity in everyday life. By illustrating common science to the community Fisher is attempting to stir interest within the community, young and old, and this approach might help fellow communicators to attract and maintain interest in how the world works.

As a result of reading the above I’ve come to a number of conclusions: a) I want to meet Len Fisher & learn stuff from him! b) I need to keep an eye open for future BrisScience events; & c) there isn’t enough time in the future timespan of the universe to read all the good science books I come across. (Well, OK, that last is pure exaggeration, but you know what I mean!) 

procrastination – something to avoid Alison Campbell Jan 16

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I’ll be using this lolcat in my classes for sure :-)

funny pictures of cats with captions

And seeing it spurred me to write a bit about studying at university, for those of you who’ll be heading that way this year. Namely, that it’s not like being at school.

At uni, you’re expected to take responsibility for your own learning. You’re not going to be chased up to come to class, for example. (Having said that, I do e-mail to anyone who’s missed two or more lab classes, asking what the story is.) Although you shouldn’t take that as licence to wag lectures – too much goes on in them that you can’t really afford to miss. Most lecturers will probably provide their first-year students with study guide notes, but the lecture itself is more than going over those notes. They’ll be put in context; there’ll be interesting little anecdotes, quizzes, all sorts of stuff.

And you certainly shouldn’t miss a lab class without good reason. They’re an essential part of the paper, & if you miss more than 1-2 without providing a medical certificate or some other documentation, you may end up failing the course. Not a good thing at all. In fact, failing to attend a compulsory class, or hand in a compulsory item of assessment, might have the same result. If you know in advance that you’re going to be away, or that you need an extension on an assignment (for a good reason! "I didn’t get around to starting it until last night…" is unlikely to be viewed with any degree of sympathy), then talk with your lecturer or tutor & see what can be done. I’ll do all that I can to help someone who comes to me early when they recognise that they need help, but there’s next to nothing I can do for someone who turns up at my office for the first time, the week before the final exam.

Which I guess brings me to the point of the lolcat – don’t procrastinate. Manage your time properly. Make lists. Plan ahead. Don’t leave things till the last minute. The potential penalties for not doing this can be quite severe. Our registrar & I are working on approving enrolments at the moment (in fact, both of us were in the office for most of today, which is a bit dire on a lovely sunny Saturday!), and every so often a ‘re-entry appeal’ crops up. These are from people who, for whatever reason, have failed more than a certain proportion of their year’s program of study, & so are not automatically eligible to return to the university. Some are on medical grounds – but in all too many of these appeals the reason given for failing is along the lines of ‘I didn’t manage my time &/or workload properly’, often accompanied by ‘I didn’t ask for help when I should have’. If someone in this position is given re-entry, then they’ll have to repeat the papers that they failed or, if they change programs, take different ones at the same level. There’s a big cost in this, in both money & time – it may extend the time taken to complete the degree by up to a year, & that’s a lot of fees & student loans.

Procrastination can be expensive. Don’t do it.

rather nice zoological videos Alison Campbell Jan 14

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Over at Terrapin Procrastination there is a lovely long list of zoological videos for you to watch. (I don’t know whether or not to thank PZ for directing me there – right now I don’t have time to procrastinate!). My favourite description from the list would have to be "“sea angel” (pelagic nudibranch) kills and eats a “sea butterfly” (pelagic snail)(with disconcerting Japanese soundtrack!)", but they all sound good & I think I will be up for a little evening video-viewing for a while. (Yes, I do watch films from time to time, but these are rather different from Dean Spanley & that ilk!) I hope there’s something there to titillate your fancy :-)
 

on the shoulders of giants Alison Campbell Jan 13

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One of the things that sets science apart is the way that it operates, building on the work of others and accepting, rejecting or altering understandings as new data come to hand. The idea that science is so open to change seems to be one of the hardest things to get across, in the classroom & in society at large: there seems to be constant surprise that scientists might alter their conclusions on an issue in the light of new information, and that each generation of scientists builds on the work of those who have gone before them.

That last point is perhaps exemplified by this quote from Isaac Newton: ‘If I have seen further it is by standing on the shoulders of giants‘ (Newton was writing to his colleague, Robert Hooke, at the time, & I have heard it said that he was being rather snarky; Hooke was a small man.) Now Orac has a wonderful post about stepping back into the past in the medical world – how much of what doctors do today is dependent on the discoveries & advances of previous generations. You could substitute ‘scientists’ for ‘medical doctors’ & the message would be the same. [Warning: there is a graphic description of a pre-anaesthesia operation on a malignant breast tumour - perhaps not best for reading over lunch...]

(Orac’s post could be a good basis for a classroom thought experiment; some of his commenters give some good supporting reading material, in the form of science-fiction novels based on the back-in-time premise. Now, if I could only think of a way to fit this into my lectures…)

the science of lolcats Alison Campbell Jan 12

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By now, my readers, you have probably cottoned on to the fact that I enjoy lolcats :-) But it’s OK – because they’re scientific! (For some reason the cats appear to be more into physics than biology…)

funny pictures of cats with captions

I actually quite like using images like this occasionally in my lectures, to liven things up or make a point. Anyway, hopefully you’ll get a giggle out of some of them.

funny pictures of cats with captions

Unfortunately this next one should really be labelled ‘meiosis’ – but that makes it useful as I can ask what’s wrong with the caption.

Humorous Pictures

Feline physics – different laws apply…

funny pictures of cats with captions

 

funny pictures of cats with captions

 

cat

Back to the serious stuff in the next post :-)

 

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