The freshwater sharks of Brisbane

Brisbane residents who pay attention to the news are probably aware by now that the city’s river, even in its upper reaches, often has bull sharks of potentially dangerous size in it.

In fact, if you go to College’s Crossing, which is close to Ipswich and has a large picnic area on a stretch of the river with clean, fresh water full of swimmers in summer, there are shark warning signs permanently up.  (Brisbane gets its drinking water from just beside this spot, so the water is definitely 100% fresh.  For some reason I don’t understand, it’s only a relatively short distance further down from College’s Crossing that the river suddenly takes on its brown murky quality which is then maintained all the way to the mouth.)

The reason I’m talking about this is because a large bull shark appears to have been spotted this week up near College’s Crossing, which (according to this report) is 90km from the river mouth.   It also says that before the Mt Crosby weir was built, they had been recorded as far inland as Lowood.   That’s a long, long way further inland.

It’s also been reported recently that bull sharks jumping out of the river in the inner  city stretch is not an unusual sight for the ferry captains:

“The warmer the water, the more times you will see them jumping,” he said. As the sun gets up, that's when you will see them jumping.

“About two years ago the river was a little bit cleaner than usual and everybody was seeing them. You ask any City Cat master, they'll say the same thing. They see them jumping all the time.”

As well, their aerials show the sharks are also more active underwater as the river at this time of year.

Sharks found upstream are normally less than 1.5m long and pose little threat to people.

However, dog owners have been warned to keep their pets out of the river at dusk and dawn, when sharks are most active.

There have been numerous reports of dogs being taken from the river's edge and even instances of more ambitious sharks taking on larger prey.

In 2005, Ipswich locals were shocked after a bull shark attacked a race horse being put through its paces in the Brisbane River at Kholo.

So, how does this shark manage to live in fresh water? I see there was a story on ABC's Catalyst show in 2003 explaining this.  Here are some extracts from the transcript:

Richard Pillans: We’re about 85km from the mouth of the Brisbane River, we’ve got fresh water for at least 20 km downstream of us, and there are sharks in here, there’s a lot of sharks in here, and it is really unusual and most people in Brisbane don’t realise they’re basically in their backyard all the way through the Brisbane River. Almost all sharks will die in fresh water, but what’s really unique about the bull shark is that it’s equally at home in both salt water and fresh water. ...

The team think that there are four key organs involved - the liver, the kidney, the rectal gland and the gills. The liver of the bull shark is extra large, it’s the animal’s salt factory. It produces salt in the form of urea.

A/Prof Craig Franklin: Urea production and the liver is the major site so it has to be pretty big. If the shark is in salt water this salt is then stored in the kidney. As it swims upstream into fresh water, excess salt is excreted in the urine.

Neil: They will retain less urea in fresh water than sea water, so there’s a clear change between the two.

Narration: The shark also regulates salt levels using the rectal gland and the gills. Pure salt can be taken in or excreted through the gills depending on the outside water.

Richard Pillans: Different in structure between the two.

Narration: Incredibly they think the very structure of gills would gradually change as the shark swims from fresh to salt water.

Thus concludes today’s nature lesson.

More cautionary tales

Time for a perennial favourite topic: don't do it kids, something bad will happen.

[Hey, if a blogger who calls himself socially conservative can't try and point out that for humans, sex is, despite all its obvious fun aspects, actually a pretty serious thing with consequences, who can?] So here's the latest round up:

* Do I have to?

A "birds and the bees" talk with your kids isn't complete without a discussion of oral sex, according to a new study that found a connection between oral sex and old-fashioned intercourse. The three-year survey found that teens who had oral sex by the end of ninth grade were at the highest risk of having sexual intercourse during high school. These teens had a 25-percent chance of having intercourse by the end of ninth grade and a 50-percent chance by the end of 11th grade.

Well, I guess it's no great surprise that a teenager heavily into one form of foreplay is likely to soon try everything else, but still, explaining all varieties of sex (apart from the one that leads to babies) is a task that probably has only become a parental obligation in recent decades.

* Over-sharing again

I see that irritating writer-blogger Sam de Brito once again over-shared by telling us about how he caught genital herpes when he was in his 20's. (He's previously told us about catching crab lice from a backpacker in the same decade.)

The piece is all a bit of a two edged sword. On the one hand, you can take it as a cautionary tale for safe sex. On the other, he has a doctor talking about how people are rather hypocritical about this disease, with the aim of helping overcome the shame of having caught it.

The net effect: nothing in the article is likely to make people change behaviour, I reckon, which just reduces it to something else icky I wish de Brito hadn't shared with us. It does, however, have some interesting figures in it, regarding the percentage of people who have both forms of herpes.

* Oral not harmless, part 2

There's also been a fair bit of publicity lately about how another study (this one from Sweden - which is appropriate I guess given their libertine reputation) showing a correlation between high rises in oral cancers with increased rates of oral sex:

"This kind of cancer traditionally affects males who have been smoking and drinking all their life, and now in their mid-60s they are getting head and neck cancer," he said. "However, HPV cancer we are seeing in younger patients who have never smoked."

Strangely, though, this is noted:

Similarly high rates have also been seen in Europe, where a new Swedish study has shown a strong correlation between oral cancers and oral sex. Oddly, the rising rates have not been seen yet in the Southern Hemisphere in Australia and New Zealand.

The cause is thought to be the human papilloma virus, for which we now have the vaccine which I think few teenage Australia girls are not having.

This should improve things gradually for head and throat cancer too, I guess, but still if you're in your 20's or 30's and acting like Sam de Brito, you're not going to be getting the benefit of that.

* Start dating older women

If you're 13, probably best to avoid sex with your 10 year old girlfriend. (The article at the link notes that even this is not the youngest recorded age for pregnancy.) Ick.

* Now to contradict myself

Slate recently had an interesting slide show which contrasted the European approach to teenage sex education to that in America. It made some interesting claims:

Dr. Amy Schalet conducted in-depth interviews with teens and parents about adolescent sexual mores in both countries. She found that in the United States, teen sexuality is dramatized as an "overpowering force." Parents commonly talk about their kids' hormones "raging out of control." If teen sexuality is destined to be reckless and dangerous, then fear is the only hope of controlling it.

Europeans, such as the Dutch, by contrast:

...view teen sexuality as being "right." The Dutch use the phrase "being ready" to talk about how their teens will know they are prepared to have sex. They spend less time and effort trying to prevent young people from becoming sexually active, and more on educating them to be responsible when they do.

As I noted from another article some time ago, the Dutch teenagers generally start sex later, despite all the openness about how its done and precautions, etc. Yet, that earlier article noted that there are likely other cultural reasons going on to explain the low rate of teenage pregnancy, apart from the intense sex education.

It's interesting to contrast this with, say, alcohol use. It seems now that most experts here think the well meaning middle class parent who lets their 16 year old take some alcohol to a party on the basis that they should be allowed to do openly something they will do anyway, are in fact doing the wrong thing. Yet, the gradual introduction of alcohol with family dining in some European countries seems to work OK.

In the Australian context, I remain similarly skeptical of parents who allow (say) their 16 year old to have their girlfriend or boyfriend stay over for sex, on the basis that it's better that it's done there than in the back of a car or park.

Anyhow, the right balance in how to approach sex education seems as tricky as ever.

The potato correction

In March 2008, I noted a comment in a book review in The Guardian that a person could live indefinitely on potatoes alone.

According to this article, about a man who is going to eat only potatoes for 2 months, that's not quite right:

Much research has been conducted on potatoes, and the conclusion drawn by every medical doctor and nutritionist on the planet is that you have to be nuts to think you can live off of potatoes.

To Voigt's credit, his lighthearted stunt will educate the public about many healthy aspects of the potato: a decent and inexpensive source of vitamin C, vitamin B₆, potassium, magnesium and, with the skin left on, dietary fiber.

Also, low-carb advocates are harsher on the potato than science allows them to be. Some potato varieties, prepared correctly, can be as healthy as the much-lauded whole grains. [7 Diet Tricks That Work]

Voigt didn't enter this diet blindly. He told LiveScience he first consulted with a doctor and dietician to confirm he could go 60 days on just potatoes. You need healthy kidneys to process the excess potassium delivered by 20 potatoes a day. You also need a store of nutrients potatoes lack, such as vitamin A for proper vision, or else exit this diet blindly.

(If you're wondering why a man would eat potatoes only for 2 months, it's because he's executive director of the Washington State Potato Commission. I guess this part of the job wasn't mentioned in his salary package.)

Seeing this blog has an inordinate amount of international influence (ha), I just thought I should note this.

Just read a book

New Scientist reports that the latest airplane bomb scare may stop plans for in flight wi-fi and mobile phone use:

In-flight Wi-Fi "gives a bomber lots of options for contacting a device on an aircraft", Alford says. Even if ordinary cellphone connections are blocked, it would allow a voice-over-internet connection to reach a handset.

"If it were to be possible to transmit directly from the ground to a plane over the sea, that would be scary," says Alford's colleague, company founder Sidney Alford. "Or if a passenger could use a cellphone to transmit to the hold of the aeroplane he is in, he could become a very effective suicide bomber."

Manufacturers of the technologies will not welcome this fresh security concern, having finally gained airworthiness approval for their in-flight cellphone and Wi-Fi systems by proving that their microwave transmissions do not interfere with avionics.

Oh dear, how sad. (Actually, I couldn't care less. There should be more spaces in the world where mobile phones can't reach.)

LHC discussed

The New York Times has a good article about the Large Hadron Collider. 

Here’s a key part:

But for all the euphoria in Geneva these days, the collider is still operating under the cloud of Sept. 19, 2008. That is when the electrical connection between two of the collider’s powerful superconducting electromagnets exploded, turning one sector of the collider ring into a car wreck and shutting down the newly inaugurated machine for more than a year.

As a result, the machine is operating at only half power, at 3.5 trillion electron volts per proton instead of the 7 trillion electron volts for which it was designed, so as not to blow out the delicate splices. At the end of 2011, all the CERN accelerators will shut down for 15 months, so that the suspect splices — some 10,000 of them — can be strengthened and an unknown number of magnets that have mysteriously lost the ability to handle the high currents and produce the high fields needed to run the collider at close to full strength can be “retrained.” ….

The collider will start up again in 2013 with proton energies of 6.5 trillion electron volts, but it is not likely to reach full power until 2014, if ever.

The smart one writes

Malcolm Turnbull sounds smart and well informed in his column in the SMH today in which he talks about his support for a private member’s motion to stop the patenting of genes. 

Tony Abbott meanwhile was at the Melbourne Cup forgetting the name of the race favourite:

TONY ABBOTT, OPPOSITION LEADER: The Thing Is is plainly going to be the sentimental favourite.

So You Think, Tony?

Suspicion correct

Recently, when the issue of how much water the Murray-Darling system needs (and how much less will be available for irrigation) was the hot topic, Australians were also hearing a claim that the country had already become a “net importer”of food. 

I heard it on a right wing radio show (Michael Smith on 4BC in Brisbane, who, as with all right wing radio jokes jocks also swallows any climate science skeptic argument without a second thought.)  

I immediately thought that this claim could not be right.  And I was correct.

As Ross Gittins says: 

This is all nonsense. Australia? A net importer of food? Yeah, sure. If you fell for it, your bulldust detector has seriously failed you in the media space.

He then explains how this silly claim came to be calculated.   The true situation is as follows:

According to figures compiled by the Department of Foreign Affairs and Trade, in calendar 2009 we had total food exports of $25.4 billion and imports of $11 billion, leaving us with a surplus of $14.4 billion. Even if we ignore unprocessed and look only at processed food, we still had a trade surplus of $5.8 billion.

Why did it take so long for the media to note this correction? 

Colebatch on Indonesia

We don’t often read all that much about Indonesia in our press, unless its related to Muslim terrorism.

Colebatch’s article in The Age today gives a good catch up picture.

Wait a minute, I’m thinking

The Guardian has an opinion piece entitled Is climate science disinformation a crime against humanity?

It ends with:

The corporations that have funded the sowing of doubt on this issue are clearly doing this because they see greenhouse gas emissions reduction strategies as adversely affecting their financial interests.

This might be understood as a new type of crime against humanity. Scepticism in science is not bad, but sceptics must play by the rules of science including publishing their conclusions in peer-reviewed scientific journals and not make claims that are not substantiated by the peer-reviewed literature. The need for responsible scepticism is particularly urgent if misinformation from sceptics could lead to great harm.

We not have a word for this type of crime yet, but the international community should find a way of classifying extraordinarily irresponsible scientific claims that could lead to mass suffering as some type of crime against humanity.

I can see certain problems with the concept, but then again it could mean most participants at the Catallaxy blog in a Gulag while me and my side take a year or so to decide whether prosecutions are sustainable.    I therefore see a certain merit.  

Fry-ing feminists

Stephen Fry was in the English press last weekend due to some rather incautious (to put it mildly) comments he made regarding women and sex, part of which includes:

"I feel sorry for straight men. The only reason women will have sex with them is that sex is the price they are willing to pay for a relationship with a man, which is what they want," he said. "Of course, a lot of women will deny this and say, 'Oh no, but I love sex, I love it!' But do they go around having it the way that gay men do?"

Fry says that heterosexual "beats" don't exist for this very reason.

One journalist feminist retorts with some sense, but also some silliness:

Women are just as capable as men are of enjoying sex. We don't go cruising or cottaging on Hampstead Heath because we don't need to. Cottaging on Hampstead Heath is presumably a hangover from the days when, sadly, [homosexuality] was illegal… Women have other ways to get our thrills, and we can go and get them in bars or clubs. Having said which, we probably also do it in parks sometimes too. It's just that we don't call it cottaging. I'm sure I've done it in parks in my time.

Well, surely both of them are over-selling their arguments. It's very silly of Fry to suggest (he now says it was out of context anyway) that all women view sex as a "price to pay" for having relationships. On the other hand, I'm sure the number of women who have met a man in a park and had sex with them in the bushes within 10 minutes is vanishingly small. (Although if you look at women who are silly enough to be impressed by, say, rugby players, the sex-in-the-toilet scenario they sometimes engage in is as close to gay men's behaviour as you can get. But, now that I think about it, there is a good chance that is more about bragging rights than their own sexual gratification, so in that sense it's not like men in the bushes after all.)

The simple truth lies in the middle (and of course I'm speaking in generalities here, but that doesn't mean it's inaccurate): yes, women enjoy sex, and yes, men are much more readily capable than women of separating sex from emotions.

The irony is that feminists think they are scoring a hit if women feel freer to act like men, when it would align more with the psychology of most women to concentrate on encouraging men to have more regard to the emotional and physical consequences of the act.

Re: Salmon

Nature has a story about a theory that a large patch of iron fertilized ocean caused by a volcanic eruption may have resulted in this year's big Canadian salmon run:

Parsons' suggestion relies on a study in Geophysical Research Letters by Roberta Hamme of the University of Victoria, British Columbia¹. The paper links the 7-8 August 2008 eruption of the Kasatochi volcano in the Aleutian Islands to a huge phyotoplankton bloom later that month. The eruption wasn't particularly large, but a storm spread its ash over a wide area. The resulting bloom was the biggest in 12 years of records, covering 1.5-2 million square kilometres of ocean. "We'd never seen anything like that," says Hamme.

Others are very skeptical that this is a very plausible explanation. All interesting, nonetheless.

Never too busy...

...to rubbish Tony Abbott.

Last week, we had this excruciating display of self inflicted gormlessness:



I mean, what was his initial refusal to back Hockey's plan, which had been discussed in Shadow Cabinet, all about?

But today I see that Tone's real agenda over the last few weeks has been to get fit for a half Iron Man event, despite a calf injury:

While the Opposition Leader has been carrying a sore calf muscle for a few weeks, it didn't stop him from swimming 1.9km, cycling 90km and running 21km in yesterday's Half Ironman race at Port Macquarie, midway between Sydney and Brisbane.

Cheered on by wife Margie, who planted a congratulatory kiss on his cheek as he crossed the finish line, Mr Abbott completed the course in six hours, 43 minutes and 42 seconds....

He did, however, express some pride in his time of two hours and 38 minutes for the 21km running leg, given that he has been struggling with a calf muscle twinge for the past few weeks, which hampered his training.

If only he devoted the same amount of effort to looking and sounding like a credible alternative PM. (Oh yes, he's apparently already conned a significant number of voters in that regard, just as did a certain K Rudd for an inordinate length of time.)

In praise of Sheldon

I only started watching The Big Bang Theory a few months ago in re-runs,but I have to say, I find much of it very funny. There's not much doubt that for most viewers the comedic core of the show is Sheldon, who Slate noted last year is (presumably, even though the writers deny it is deliberate) the first sitcom character with Aspergers Syndrome.

Despite the frequent sexual elements and jokes, I would say that the two funniest episodes I have seen concentrated on Sheldon and hence were pretty asexual. The first one was the story of how Leonard first came to move in with Sheldon, (The Staircase Implementation).

The second was on TV last night, featuring Sheldon deciding to stay safe in his bedroom until the singularity arrives and he can upload himself into a robot. In the meantime, he creates a tele-presence robot version of himself, which he get Leonard to drive to work. This sequence is currently on Youtube, and brought tears to my eyes.

Live long and prosper, Sheldon.

UPDATE: I am happy to see, from this recent LA Times episode review of the current season, that Sheldon's "girlfriend" Amy is still around. She has also been amusing me greatly in the couple of episodes I have seen in which she makes an appearance.

Slum life this is

The first of Kevin McCloud's 2 part doco "Slumming It," in which he spends a fortnight living with families in the middle of Mumbai's biggest slum, was great TV on the ABC last night. One minute appalled by the open sewer drains (full of mystery chemical sludge as well as excrement,) the visiting rats in the bedroom at night and the terrible working conditions in the mini industries in the slum, the next minute McCloud is marvelling at the apparent general happiness of the community and the high degree of social interaction of all age groups in such a place. (Well, the latter is kind of hard to avoid with things like 21 people sharing a tiny house. He also notes often that it is a million people living in about one square mile.)

As an architect, McCloud is interested in how the built environment works in a place like this. (He notes that many planners, and Prince Charles, have taken to saying that it has lessons to teach the West.) Yet the one factor he hasn't mentioned is the obvious high degree of religiosity of the people there, and the role that the degree of fatalism in the Hindu religion almost certainly has on the perception of the residents.

I also thought the show should be watched by the libertarian inclined as an object lesson in the limitations of self regulation of society. The industries there are completely unregulated and untaxed; a perfect little Randian experiment, I would have thought. And yes, the slum does show the inherent innovation and capitalist tendencies in self organised human societies. But it also shows that capitalism, at least in a culture such as India's, can be very slow to self correct for the abuses and poor treatment of its workers.

You can catch the show on the ABC’s iView still.

Salmon mystery

The BBC has a detailed story about the surprising strong return of sockeye salmon to their spawning rivers in Canada this year.  Last year only a million came back; this year, 34 million!

The problem is no one understands what is going on.

Islamic news

*  There’s always someone in the family who has an unusual conversion.  Tony Blair’s sister in law has had a conversion experience in Iran:

She decided to become a Muslim six weeks ago after visiting the shrine of Fatima al-Masumeh in the city of Qom.

"It was a Tuesday evening and I sat down and felt this shot of spiritual morphine, just absolute bliss and joy," she said in an interview today.

When she returned to Britain, she decided to convert immediately.

I could be wrong, but sudden conversions to this religion seem pretty rare,  unless you’re in an Indonesian prison.   Seeing she’s a TV journalist, I would have been more amused if she had started to insist on an on screen burqa instead of just a hijab.

*  There are two stories about men in legal trouble in the Middle East for using the internet for sexual purposes.   An Egyptian Imam in Dubai is alleged to have sent rude pictures of himself to women via Blackberry (and was the victim of a “sting” by a male policeman posing as a woman).   In Saudi Arabia a man who was making money by “renting” on line rooms in which women would strip is facing arrest.

I am curious:  just how large are the cyberpolice departments in these middle east countries?   If there are going to try to stop every man who sends a rude pic of himself from his mobile phone, they will be the biggest employment field in the region.   And if these countries don’t block overseas sites, when will they realise there is no holding back the tide?

Suffer, snow bunnies

Look, if people grow up in a snowy country, skiing is an unobjectionable past time.  But in Australia, where (if you live outside of Sydney or Melbourne at least) you can just about have 7 days in London (or, at the very least, a week in Tokyo)  for the same price as a long weekend on the skifields, it’s always struck me as an elitist hobby.  And besides, the couple of times I did try to stand up and move on skis, I fell over a lot.

So, being the jealous, nasty person that I am, if the Grammar school kids all end up with osteoarthritis, I’ll just snigger in the background. 

Not your average Parisian evening…

There was a story in the SMH yesterday which is notable for the fine sense of understatement in the final line.   First, I’ll edit the events (tragic as they are):

A baby was killed and several more people seriously injured when a family of 11 threw themselves from a third-floor flat to flee a man they mistook for the devil, French investigators said….

Among the injured they found an entirely naked man of African origin with a knife wound in his hand and two children, a baby and a two-year-old girl. The baby died later after receiving hospital treatment in Paris.

The assistant prosecutor from Versailles, Odile Faivre, told reporters the incident began in the early hours when a group of 13 people were watching television in an apartment and the naked man heard the baby cry.

"The man got up to prepare a bottle for the baby when his wife, seeing him, screamed 'It's the devil, it's the devil'," Faivre explained.

In the confusion following this apparent case of mistaken identity, the naked man's sister-in-law stabbed him in the hand and he was ejected through the front door of the flat. When he attempted to get back in, panic erupted.

"The other occupants of the flat fled by jumping out of the window," Faivre said. According to police, one man jumped with the two-year-old in his arms and crawled two blocks away to hide in bushes, screaming: "I had to defend myself."

And the final line:

"A number of points remain to be cleared up," Faivre said.

Things of note

I’m going to be pretty busy this week, and really should try to impose a ban on myself using the internet. But such attempts usually fail, so you may as well keep checking in and seeing what turns up here.

This morning, I recommend the following:

* quite a good, long article in The Guardian on daily life in the nearly completed International Space Station. (They don’t dwell on the toilet, but you already know all about that from my earlier posts.)

* yet another tragic case of erotic autoasphyxiation actually ends up teaching medical science something new.

* GQ, of all magazines, has a long article on suicide chat rooms, and the coming trial of a guy charged with encouraging suicides. All very chilling, although the article also claims that some suicide chat rooms have positive effects and can help talk people out of it. But surely you would have to look at the net effect. Actually, I see Mind Hacks links to another story (this one from the BBC) about suicide chat rooms, but I haven’t listened to it yet.

Irresistible