Time travel re-visited

There’s a new paper up on arXiv by a international group of  physicists which has an abstract starting with this:

This paper discusses the quantum mechanics of closed timelike curves (CTC) and of other potential methods for time travel. We analyze a specific proposal for such quantum time travel, the quantum description of CTCs based on post-selected teleportation (P-CTCs).

A middle section that includes this:

If it turns out that the linearity of quantum mechanics is only approximate, and that projection onto particular states does in fact occur – for example, at the singularities of black holes – then it might be possible to implement time travel even in the absence of a general-relativistic closed timelike curve. The formalism of P-CTCs shows that such quantum time travel can be thought of as a kind of quantum tunneling backwards in time, which can take place even in the absence of a classical path from future to past.

And a conclusion that ends with this:

In Sec. IV we have argued that, as Wheeler’s picture of positrons as electrons moving backwards in time suggests, P-CTCs might also allow time travel in spacetimes without general-relativistic closed timelike curves. If nature somehow provides the nonlinear dynamics afforded by final-state projection, then it is possible for particles (and, in principle, people) to tunnel from the future to the past.

Unfortunately, as I seem to be finding with some arXiv papers lately, it has a very layperson friendly introduction, but for the rest of the paper, it would help to be a physicist.  I don’t know why they don’t make the conclusion a lay reader friendly version of  what their paper means. 

Still, any arXiv paper that even mentions people tunnelling from the present to the past is noteworthy!

An announcement

I like watercress salad.

Further updates later.

Update: it was a simple recipe: watercress, apple (red, although the recipe actually said Granny Smith), blue cheese and some salad onion. It was also meant to have some chives, but I forgot to add them. Dressing - simple vinaigrette (white wine vinegar, olive oil, clove of garlic, salt, pepper, bit of sugar.)

I think roasted walnuts would go well in their too - I love them in pear, blue cheese and bacon salad.

Watercress never seemed to be around when I was kid, but then again I suppose nor were a fair few things now common in the greengrocers. Some Vietnamese shops near my area sell large watercress bunches for a dollar. It was all we ate (with bread) for dinner last night. Nice.

Eight legged oracles

Gillard's chances get a legs-up

It's hard not to be amused at the way everyone now wants to consult octopodes as oracles. Is there a quatrain from Nostrodamus that predicted this development?

"The Nations will fight on the field of the beasts
The spawn of the Kraken will foretell the outcome
The true prophets of the universe are revealed
My book sales plummet"

Whinging Pom located

According to a (largely) favourable  article on the BBC website about Brisbane as a place to live:

Surprisingly, it's not Sydney's stunning harbour views that are pulling them in, nor the lure of seeing the Ashes battled over once again at the iconic Melbourne Cricket Ground. Instead, record numbers are making their way to Brisbane, halfway up the east coast where, according to NatWest's recently-published Quality of Life Index, every 10th person is a pommy.

In the comments following the article, quite a few people from the UK say they like the place, but this comment sounds so stereotypically “whinging Pom”, it’s not a send up, is it?:

 I've been here for 50 years and have regreted it ever since I arrived and would have liked to return home but have never been able to afford to, but in my will I have requested that my ashes be returned to my country of birth and scattered on English soil. This place might be ok for a holiday but that's all.

Electric options

Yamaha has a new electric motor scooter out in September in Japan, and then onto the world. (Well, at least Taiwan, Europe and China.) Not sure about the performance, though:

The EC-03 can travel 43 kilometres (26.6 miles) on a single six-hour charge from a household power outlet, which costs about 18 yen (cents) in Japan, far less than the cost of powering a conventional 50cc scooter, it said.

Meanwhile, what was that ad for an electric Mitsubishi car I saw today wrapped around the front of The Australian?  Must be about this small shipment due soon of i-MiEVs, which are only destined to lease to government bodies and companies anyway. The car did get a pretty good review, though. It does 140-160 km on a single charge, and can go up to 130kph. Acceleration is fine with a full, 4 adult, load. Nice.  Just  got to wait for the price to come down.  A lot. 

Hating Tara

What on earth do people enjoy in The United States of Tara? I watched the first episode of the first series, and saw little bits of subsequent episodes. Surprised that it was renewed for a second series, I watched an episode from that last night.

It's a show that works on absolutely no level. An example of this weird genre of quirk dramedy that is not funny or dramatic in any realistic sense, it lives solidly in what has become a cliche-ridden field of liberal takes on diversity in family. Outwardly normal looking family with dark secret - check; gay son - check; slutty daughter getting hypocritical mixed messages from parents - check; nice gay neighbour couple - check; mental illness induced by mistreatment in family - check.

And do middle class families in America really now use "f**k" in every second sentence, no matter who they are talking to? Doesn't someone ever say to them that it's a complete bore when any word becomes just a verbal tic?

I don't find any of the characters particularly likeable, except perhaps the son who is sensitive (as all gay teenage boys are - excuse me while I roll my eyes a bit.) Yet even the storyline last night involving him attempting to get sexually experienced with a girl did not ring true. (A lame and unrealistic attempt at humour when he tries to put on condom while completely un-aroused.)

The mental illness the show is based on is a diagnosis that is widely disputed, and I think virtually never takes as extreme a form as shown here. The relationship between the parents is more than a touch unbelievable, if you ask me. (Last night featured sex in the yard in the middle of the day following Dad getting screamingly upset with his dishonest wife.)

There is nothing to like about the show. Yet liberal viewers appear to lap it up, because, you know, all families are swearing, dysfunction car wrecks of equal validity.

I hate it.

Dial 000 and ask for emergency massage therapy

Whisker stimulation prevents strokes in rats, study finds

This is a very surprising story. Stimulating the right whisker in a rat has remarkable effects on blocked blood flow in its brain:

A stroke usually happens when a main artery bringing oxygen and nutrients

to the brain either ruptures or is blocked by a clot, causing partial brain death. The key to preventing strokes in rats whose main cerebral artery has been obstructed, UCI researchers found, is to stimulate the middle part of the brain.

The team discovered that mechanically stroking just one whisker for four minutes within the first two hours of the blockage caused the blood to quickly flow to other arteries - like cars exiting a gridlocked freeway to find detours.

But unlike freeway off-ramps, which can quickly clog, the alternate arteries expanded beyond their normal size, opening wide to allow critical blood flow to the brain. The technique was 100 percent effective in preventing strokes in rats with arterial obstruction.

This is going to be hard to test on humans, as ethics committees probably have something to say about experiments involving deliberately induced strokes. But as the researchers say:

In people, "stimulating the fingers, lips or face in general could all have a similar effect," says UCI doctoral student Melissa Davis, co-author of the study, which appears in the June issue of PLoS One.

"It's gender-neutral," adds co-author Ron Frostig, professor of neurobiology & behavior.

He cautions that the research, funded by the National Institutes of Health, is a first step, albeit an important one. "This is just the beginning of the whole story," he says, "with the potential for maybe doing things before a victim even reaches the emergency room."....

People believed to be suffering a stroke are currently told to lie still and stay calm in a quiet environment. Frostig says a good massage, listening to a song or otherwise stimulating the right nerve endings might work better.

Kleinfeld cautions that the rodent findings might not be relevant to humans. But with such clear evidence that strokes in rats were prevented, he says, "it would be criminal not to try" controlled human studies. That could be tricky, since it's not possible to predict when someone will have a stroke.

North Korea in Japan

Last night’s Foreign Correspondent, on ethnic Koreans in Japan, and the support they have received from North Korea, was particularly interesting.

Needs a bottle of Drano the size of the Empire State Building

The Independent reports:

Enough fat to fill nine double-decker buses is being removed from sewers under London's Leicester Square.

A team of "flushers" equipped with full breathing apparatus has been drafted in with shovels to dig out an estimated 1,000 tonnes of putrid fat…

Danny Brackley, the water company's sewer flusher, said: "We're used to getting our hands dirty, but nothing on this scale.

"We couldn't even access the sewer as it was blocked by a four-foot wall of solid fat."

In praise of the scum of the earth

Green machine: A new push for pond scum power - tech - 12 July 2010 - New Scientist

New Scientist reports on why making biofuel from algae seems to be a good idea, but also notes the problems. On the one hand:

"Ten million hectares of algae could supply all US transportation fuel," says Greg Mitchell of the Scripps Institution of Oceanography in La Jolla, California. That's less than 3 per cent of the area farmed in the US – and algae can live in seawater in the desert.

On the other hand, the penultimate paragraph takes quite a lot of the gloss off the concept:

And ultimately, production will require suitable climate, land, water, nutrients and CO₂, all at one site. Even using waste land, seawater, sewage and smokestack CO₂, Benemann thinks this will limit the potential for algal biomass to the equivalent of 1 per cent of the CO₂ now being released, or less. "But that's still a gargantuan amount. Let's hope we can do that much."

Hmm. Not exactly going to save the Earth, then; but maybe can make a worthwhile contribution?

Techno-optimism remembered

Tom Swift and the birth of American techno-optimism � Climate Progress

I should be doing something else, but can't help linking to this post about the Tom Swift novels, which have a much longer history than I realised.

I read the later incarnation of these (written in the 50's and 60's) when I was a child, and remember enjoying them a lot. As I have noted here before, there was a lot of basically optimistic science fiction written for the youth market in that period. Now that's been replaced by futuristic novels set in dystopias or otherwise pessimistic about the future, social realism about children dealing with broken families and such like, or fantasy that may be well written, but only connects with reality when dealing with relationships.

If I were a commissioning editor, I would be very interested in trying to re-establish the genre of techno-optimism for the youth market. You see, I haven't quite given up on that idea; just become depressed about the lack of political and social will to pursue it. Telling children not to expect science to help in the future is not a good way to break that cycle.

While I’m busy, consider the tortoise

Various issues are pre-occupying me at the moment, but while I am distracted, someone has written about the rise of pets, in particular tortoises, in England in the journal Post-Medieval Archaeology:

As Dr. Thomas says, "Although we have archaeological evidence for terrapins and turtles from the 17th century, this is the first archaeological evidence we have for land tortoise in Britain. It seems very likely that this specimen was imported from North Africa or the Mediterranean; by the later 19th-century there was a dramatic rise in the commercial trade in tortoises from these regions to satisfy the growing demand for pet animals".

The morality of keeping pets was considered highly suspect in the strict religious doctrines of Medieval and Early Modern society, and although there was an avid fascination in exotic creatures at the time, this seems to have curiously bypassed the tortoise.

Attitudes towards pets began to change in the 17th century, particularly under the famously dog-loving Stuart kings, and the reputation of the tortoise had certainly risen high enough by the early 17th century for the ill-fated Archbishop Laud to have kept one.

During the 18th and 19th centuries a more 'modern' attitude to pet animals gradually emerged. The sculptor Joseph Gott created sentimental statues of dogs during the 19th century, and in 1824 the Society (later Royal Society) for the Prevention of Cruelty to Animals was founded.

Here’s something I didn’t know:  the great tortoise trade of the 20th century:

As Dr. Thomas reveals, "Unfortunately, this interest in keeping exotic pet animals resulted in the capture and translocation of millions of wild tortoises each year during the 20th century. The animals were crated in ships and kept in appalling conditions; countless tortoises died during this journey and those that survived fared little better, given away as fairground prizes and kept by people with little knowledge of their upkeep. It was not until an EEC regulation in 1988, that this trade in wild tortoises was prohibited".

Medieval report

Guess where we went yesterday?

It's a place where men oil themselves and wrestle, while other men watch:


It's a place where walking tree/wood nymph thing-ees wander:



It's where a hell of a lot of people dress up and wander around



and a woman can indulge her favourite past-time: firing replica breach canons, causing much smoke and sound,



while men dress up as old soldiers and hit each other for fun and (sort of) entertainment:

(I would move that crappy video to the centre if I could work out how.)

Yes, it was the Abbey 2010 Medieval Tournament, held just north of Brisbane.

It's been going on for years, but I've never made it there before.

One of the most interesting thing about it was that it made me realise the number of medieval themed club-like groups that must be around, lurking beneath the veneer of normal society. I spoke to one guy who was showing me how to make authentic medieval shoes and asked him: if one has a desire to be a medieval craftsman/soldier/musician, how does one go about finding entry into a group who can teach you how?

It does seem to come down to who you know, and (I suppose) attending these tournament events and begging entry into a quasi-secret society that catches your fancy. Then you too can dress up and yearn for the old (really old) days at least once a year.

Actually, it was all good fun, and next year I plan on attending as Thomas Aquinas.

Starfish Prime revisited

Bad Astronomy linked to a recent NPR story* with video of the 1962 Starfish Prime nuclear explosion in outer space. Interesting.

By the way, I've never been to the NPR news homepage before, but it has a very clean look that appeals.

* This is also, as it happens, how I found an NPR story on an old porn star. Just in case you were wondering.

Career choices of the older but not so wise

This whole stupid “cougar” business has to stop soon, doesn’t it?  NPR reports:

Diana Grandmason is a 50-year-old redhead who once ran an investments business in Florida. Perhaps an unlikely performer in adult films — but until a year and a half ago, she starred in X-rated movies, including Seduced by a Cougar.

Grandmason says she got into the porn business to follow her daughter, Bess Garren.

"Basically, she called me at work and said, 'I'm gonna go do this,' and I said, 'No you're not.' And she said, 'Mom I'm 21, this is a courtesy call, I'm doin' it.' So what choice did I have?" she explains.

But then, she decided to follow Garren.

"Originally it was signing up just so I could accompany her, and then I kinda got sold on the idea myself," Grandmason says.