Saturday, May 05, 2007

Pet food roundup: more bad news

Just more bad news

  • estimated deaths now about 8,500 with expectation of many lives limited by future renal failure
  • a mail order pet food supplier joined the recall
  • 20 million chickens may have eaten contaminated feed
  • Menu Foods admits studies have shown "cross contamination" -- foods thought to be safe are found to contain melanine

That announcement prompted ASPCA to issue its warning to pet owners.

... “Given the fact that there is new evidence of cross-contamination in ingredients that may have been considered safe prior to this news, we need to be much more aware of where the ingredients in our pets’ food are coming from,” said Dr. Steven Hansen, a board-certified toxicologist and senior vice president with the ASPCA. He manages ASPCA’s Animal Poison Control Center (APCC) in Urbana, Ill.

Hansen added: “We are strongly recommending that pet parents immediately investigate, via their pet food manufacturer’s Web site or by calling them directly, where the ingredients--specifically protein supplements--are sourced from.”

ASPCA recommends pet owners only feed their dogs or cats products that contain U.S.-made protein supplements.

I wonder how many US made protein supplements exist. I also suspect that manufacturers aren't going to reveal their supplement sources. Your best guide may be if they don't explicitly say it's US based, then one can assume it's coming from China.

The greatness of geeks: Ad block software

Other than pop-up blockers, I've not bothered with Ad block software. The sites I go to have very rarely use obnoxious adds.

Until today. Slate had an ad, for a movie called 28 I think, that was beyond obnoxious. I happened to be using Camino (I alternate between Camino and Firefox depending on my mood and how badly behaved FF has been recently), so I turned on their Ad Block feature. Sweet relief.

This is where the greatness of geeks comes in. Ads are the primary revenue source for web content providers. The success of web browsers is tied to the success of web content. If web browsers were produced by publicly traded companies, they'd never implement ad blocking. Enter the geeks. There are enough geek-controlled browsers to keep even IE honest.

Thanks!

Friday, May 04, 2007

Boltzmann’s Brain explained

I'd blogged earlier on a Cosmic Variance article about emergent brains in the eternal soup of a senescent universe, but I didn't know the original context of the Boltzmann Brain idea. Another CV article today pointed me to one from last year that filled in the gaps. The Boltzmann Brain comes from a 2004 paper by Albrecht and Sorbo, and it was described in CV last year:
Boltzmann’s Anthropic Brain | Cosmic Variance

...Let’s posit that the universe is typically in thermal equilibrium, with occasional fluctuations down to low-entropy states, and that we live in the midst of one of those fluctuations because that’s the only place hospitable to life. What follows?

The most basic problem has been colorfully labeled “Boltzmann’s Brain” by Albrecht and Sorbo. Remember that the low-entropy fluctuations we are talking about are incredibly rare, and the lower the entropy goes, the rarer they are...
...So if we are explaining our low-entropy universe by appealing to the anthropic criterion that it must be possible for intelligent life to exist, quite a strong prediction follows: we should find ourselves in the minimum possible entropy fluctuation consistent with life’s existence.

And that minimum fluctuation would be “Boltzmann’s Brain.” Out of the background thermal equilibrium, a fluctuation randomly appears that collects some degrees of freedom into the form of a conscious brain, with just enough sensory apparatus to look around and say “Hey! I exist!”, before dissolving back into the equilibrated ooze.

You might object that such a fluctuation is very rare, and indeed it is. But so would be a fluctuation into our whole universe — in fact, quite a bit more rare. The momentary decrease in entropy required to produce such a brain is fantastically less than that required to make our whole universe. Within the infinite ensemble envisioned by Boltzmann, the overwhelming majority of brains will find themselves disembodied and alone, not happily ensconsed in a warm and welcoming universe filled with other souls. (You know, like ours.)

This is the general thrust of argument with which many anthropic claims run into trouble. Our observed universe has something like a hundred billion galaxies with something like a hundred billion stars each. That’s an extremely expansive and profligate universe, if its features are constrained solely by the demand that we exist. Very roughly speaking, anthropic arguments would be more persuasive if our universe was minimally constructed to allow for our existence; e.g. if the vacuum energy were small enough to allow for a single galaxy to arise out of a really rare density fluctuation. Instead we have a hundred billion such galaxies, not to count all of those outside our Hubble radius — an embarassment of riches, really....

Of course there's no end to the anthropic principle, which I tend to think of as an extreme application of Bayes theorem. We can be anthropic ad absurbum, and say that since we live in a rich universe we must exist in a really, really, really big and really, really, rare entropic excursion event.

Or maybe we're a dream of a more modest excursion, which is, after all, more likely.

Hmph. Cosmology is becoming about as satisfying as quantum mechanics.

Genetic testing hits the big time?

Almost every article on this discovery emphasized that this gene flaw was found in palefaces. I assume that's because intimations of genetic inadequacy are less controversial when applied to a (transiently) powerful community. In reality they've yet to study the prevalence in non-euros:
BBC NEWS | Health | Heart disease genetic link found
Last Updated: Thursday, 3 May 2007, 18:23 GMT 19:23 UK

... US and Canadian researchers found that up to one in four white people carries the section of DNA which increases the risk of heart disease by around 40%.

A separate study in Iceland found the same genetic variant was linked to a fifth of heart attacks...

... The US/Canadian team found a section of DNA - called an allele - on a specific chromosome that was associated with heart disease.

Their study of 23,000 people, showed that those who carried one copy of this allele have a moderately increased risk of heart disease.

But people who have two copies, which accounts for about 20-25 % of white people, have a 30 to 40% higher risk of heart disease than individuals who carry no copies.

Professor Ruth McPherson, of the University of Ottawa Heart Institute, who worked on the study, said: "The effect is less than that of smoking or having a high cholesterol level....

... The researchers will now check if the findings also apply to people from black and Asian ethnic minorities.

... The Iceland study looked at the same stretch of DNA in 17,000 people.

They also found that more than 20% of people had two copies of the faulty allele.

People with both copies had a 60% increased risk of heart attack, compared with those who with no copies.
The risk factors for premature heart disease of hypertension, diabetes, hyperlipidemia, smoking and male gender are as old as the hills. (Intriguingly family history doesn't usually make the list, I assume it didn't add much to the linear regression models.) For many years we've known that these variables are not fully predictive (I'm thinking 50%, but that's based on ghosts of old memories). Clearly there are other factors to be named, and maybe this gene is one of them.

This is the first mass market gene test candidate I know of, so this is a historic discovery. Once it's commercialized a gene test will be compared to coronary calcium measurement in the management of patients for whom the costs and risks of lipid therapy may outweigh benefits. It will also play a role in deciding who gets cheap life insurance.

BTW, the funny thing about laws that prevent insurers from using gene testing in coverage decsions is that they're unfair ... to insurers. Patients, of course, can use the tests on themselves. If the risks look high, they buy term insurance. If the risks are low, they don't. Poor insurer :-). Really, this stuff is just another shove towards a system of universal minimal health care coverage.

It will be very interesting to learn what this gene codes for. Not only will that open new therapeutic options, we will also suggest the benefit of this allele. It's too common in the euro population to be only dangerous ...

Venus: the forgotten planet

I was going to bed last night, and it occurred to me that I never hear much about Venus. We read about Mars, Jupiter, Saturn, Pluto (not even a planet!), Mercury ... but not Venus. Venus, the planet the most like earth -- save for one minor detail -- no tectonics. Oh, and a bit of greenhouse gas issue ...

A conspiracy? Probably not, since Wikipedia has a great article (emphases mine):
Venus - Wikipedia, the free encyclopedia

... About 80% of Venus' surface consists of smooth volcanic plains. Two highland 'continents' make up the rest of its surface area, one lying in the planet's northern hemisphere and the other just south of the equator. The northern continent is called Ishtar Terra, after Ishtar, the Babylonian goddess of love, and is about the size of Australia. Maxwell Montes, [named after James Clerk Maxwell] the highest mountain on Venus, lies on Ishtar Terra. Its peak is 11 km above Venus' average surface elevation; in contrast, Earth's highest mountain, Mount Everest, rises to just under 9 km above sea level. The southern continent is called Aphrodite Terra, after the Greek goddess of love, and is the larger of the two highland regions at roughly the size of South America.

... Venus has a number of unique surface features. Among these are flat-topped volcanic features called farra, which look somewhat like pancakes and range in size from 20–50 km across, and 100–1000 m high; radial, star-like fracture systems called novae; features with both radial and concentric fractures resembling spiders' webs, known as arachnoids; and coronae, circular rings of fractures sometimes surrounded by a depression. All of these features are volcanic in origin....

...Venus has several times as many volcanoes as Earth, and it possesses some 167 giant volcanoes that are over 100 km across. The only volcanic complex of this size on Earth is the Big Island of Hawaii. However, this is not because Venus is more volcanically active than Earth, but because its crust is older. Earth's crust is continually recycled by subduction at the boundaries of tectonic plates, and has an average age of about 100 million years, while Venus' surface is estimated to be about 500 million years old...

... on Venus, about 85% of craters are in pristine condition. The number of craters together with their well-preserved condition indicates that the planet underwent a total resurfacing event about 500 million years ago. ....Without plate tectonics to dissipate heat from its mantle, Venus instead undergoes a cyclical process in which mantle temperatures rise until they reach a critical level that weakens the crust. Then, over a period of about 100 million years, subduction occurs on an enormous scale, completely recycling the crust. [jf: I think this means the turnover starts ever 500 million years, but it takes 100 million years to exhaust the mantle heat and restabilize the crust.]

... Venus has an extremely thick atmosphere, which consists mainly of carbon dioxide and a small amount of nitrogen. The pressure at the planet's surface is about 90 times that at Earth's surface—a pressure equivalent to that at a depth of 1 kilometer under Earth's oceans. The enormously CO2-rich atmosphere generates a strong greenhouse effect that raises the surface temperature to over 400 °C (752°F). This makes Venus' surface hotter than Mercury's, even though Venus is nearly twice as distant from the Sun and receives only 25% of the solar irradiance.

Studies have suggested that several billion years ago Venus' atmosphere was much more like Earth's than it is now, and that there were probably substantial quantities of liquid water on the surface, but a runaway greenhouse effect was caused by the evaporation of that original water, which generated a critical level of greenhouse gases in its atmosphere. Venus is thus an extreme example of climate change, making it a useful tool in climate change studies.

... The permanent cloud cover means that although Venus is closer than Earth to the Sun, the Venusian surface is not as well heated or lit. In the absence of the greenhouse effect caused by the carbon dioxide in the atmosphere, the temperature at the surface of Venus would be quite similar to that on Earth. ...

... lack of an intrinsic magnetic field at Venus was surprising given that it is similar to Earth in size, and was expected to also contain a dynamo in its core. A dynamo requires three things: a conducting liquid, rotation, and convection. The core is thought to be electrically conductive, however. Also, while its rotation is often thought to be too slow, simulations show that it is quite adequate to produce a dynamo. This implies that the dynamo is missing because of a lack of convection in Venus' core. On Earth, convection occurs in the liquid outer layer of the core because the bottom of the liquid layer is much hotter than the top. Since Venus has no plate tectonics to let off heat, it is possible that it has no solid inner core, or that its core is not currently cooling, so that the entire liquid part of the core is at approximately the same temperature. Another possibility is that its core has already completely solidified.

... If viewed from above the Sun's north pole, all of the planets are orbiting in a counter-clockwise direction; but while most planets also rotate anticlockwise, Venus rotates clockwise in "retrograde" rotation. The question of how Venus came to have a slow, retrograde rotation was a major puzzle for scientists when the planet's rotation period was first measured. When it formed from the solar nebula, Venus would have had a much faster, prograde rotation, but calculations show that over billions of years, tidal effects on its dense atmosphere could have slowed down its initial rotation to the value seen today.

A curious aspect of Venus' orbit and rotation periods is that the 584-day average interval between successive close approaches to the Earth is almost exactly equal to five Venusian solar days. Whether this relationship arose by chance or is the result of some kind of tidal locking with the Earth, is unknown....
The major flaw with this article is it doesn't make clear why Venus lacks plate tectonics. There's a throwaway line about "dry crust", so maybe the theory is that Venus' solar proximity led to early water loss, the loss of water led to arrested plate tectonics (and to the CO2 accumulation and greenhouse gas effect?), then arrested plate tectonics and greenhouse gases led to a volcanism dominated globe with a hot ultra-dense atmosphere ...

I think The Onion recently suggested Dick Cheney is Venusian, which probably explains the GOP's attitude towards CO2 accumulation.

PS. If you know a planetary person, can you ask them to edit the article to clarify the tectonics/CO2/volcanism relationships?

PPS. I had a high school science teacher who was a fan of Velikovsky's "When World's Collide". Messed up my thinking for a few months. So I thought it was curious that we still don't have confident explanation for the retrograde orbit. (Alas, Velikovsky's explanation was inconsistent with basic physics.)

Enlightenment 2.0 and a Hong Kong student post on the Chinese organ trade

Connections are established, reinforced, strengthened. The river finds a new channel. The new flow alters other flows and channels. The river and the landscape think, solving problems in hydrology and geography.

That's how we imagine that our minds work. That's the way Hopfield explained it to me around 1981, when he and others returned to the long interrupted study of neural networks. That's the way Google forges connections, doing forward and back chaining. That's the way a hive thinks, and our hivemind grows.

This is a story of the Chinese organ trade, and the hivemind. It begins with a feed.

I wrote a Google Blog Search query a while back that generated an RSS feed that's tracked by my bloglines reader. Bloglines notifies me when the search returns a new link to my blog. It's a erratic process; sometimes links appear immediately, sometimes I get a link that was formed a year ago. Most often I discover a "splog" has taken a post of mine, turned it into a splog post, and I'm just seeing an externalized version of my internal links.

Every so often though, it returns something fascinating. Today it uncovered an article on China's organ trade law written by a Hong Kong journalism student today as part of a class exercise (JMSC 0042 I presume). I've corrected some trivial spelling and grammar errors. Emphases mine.
International News (JMSC 0042) - Organ Trade finally banned in China

candicecheng - May 4, 2007 @ 10:37 am · Uncategorized

Xinhua reported (May 1) that China’s first set of regulations on human organ transplant took effect on Tuesday.

The new regulations, issued by the State Council, ban organizations and individuals from trading human organs in any form. Doctors found to be involved in the process will have their practitioner licenses revoked. Clinics against the new regulations will also be suspended for at least three years. The fines are fixed to be between eight to ten times of the outlawed trade value. (See full set of regulations in simplified Chinese.)

The regulations also state that human organ transplants should follow the principle of free will. And obtaining organs, such as the heart, lung, liver, kidney and pancreas, without the owner’s permission or free will is a crime. ( Learn more about organ transplant here.)

The regulations, however, do not apply to transplants of human tissue, such as cells, cornea and marrow.

China has operated organ transplants for more than 20 years. It is the world’s second largest performer of transplants after the United States, with about 5,000 transplants operated each year.

Legal organ donations are made by ordinary Chinese at death with a donation agreement signed voluntarily during lifetime.

Nevertheless, there has been a huge gap between the demand for functional organs and the supply of donations. According to statistics from the Ministry of Health, about 1.5 million patients need organ transplants each year but there are only 10000 organs transplanted.

This gave rise to a flourishing black market of organ trade. Wealthy Chinese or foreigners who are willing to pay hundreds of thousands of dollars can arrange the deal with a broker and have their transplants done in a week’s time. It is reported that a kidney costs around $80,000. Nevertheless, most of the time, the source of the organ is unknown. (See a transplant tourism story here.)

China was recently being accused of selling organs from executed prisoners and was heavily criticized by human right groups. Officials did not deny the practice but said that they did it with the consent of the prisoners. Families of the prisoners, however, disagreed. (See full story here.) (This leads to one question: if the officials continue to insist that they are taking prisoners’ organs with their consent and not for profit, will the new regulations help to stop this “unethical practice”?)

Bloggers have different reactions towards China’s ban on organ trade. One blogger said that he was surprised that China would really go to the step of banning organ trade under the international pressure...
This so reminds me of Vernor Vinge's "Rainbows End", about which I ought to say more. A few notes, though they are probably obvious:
  1. I follow this subject, and I learned more from this blog post than from any other source in any mainstream media. There was nothing that contradicted my existing knowledge, so I have some confidence in the new knowledge.

  2. It's weird that they picked my post as one of two examples of the "blogger perspective".

  3. A connection has been established. I'm adding this Hong Kong journalism class blog to my regular feeds. What better source for an english language perspective on China?

  4. China has not enforced its laws very well, but that seems to be changing. The fine of "8-10x" the value of the traded organ strikes me as the work of someone who is serious about controlling this practice.

  5. If anything is going to save us from ourselves, it is the hivemind. Do your part.

Thursday, May 03, 2007

The brilliance of the geek mob: HD-DVD encryption key now a colored shirt

The encryption key for an HD-DVD DRM scheme has been found. Lawyers are using the infamous DMCA to eliminate it from web sites, but the Digg crowd keeps writing it back to their site. Digg has given up and seems fated to die, but ingenuity strikes back.

The magic number can be represented as a series of hex digits, which in a web browser can encode a series of colors. So this site has created a color scheme that can be decoded to the encryption key. Of course the number may also be represented as letters, binary notation, a power of e, musical notes, etc. How far will the laywers chase this down? T-shirts are being printed, wrist bands, underwear ...

The geek mob is in action. Feels like spring time (not Prague spring I hope).

Ohio TV finds pet food industry inscrutable

Imagine that, the industry doesn't like visitors ...
WBNS-10TV, Central Ohio's News Leader - News - 10 Investigates: What's Really In Pet Food

...10 Investigates found out quickly that the government -- and the industry -- did not even want to discuss the subject. The FDA refused to give 10 Investigates a one-on-one interview, claiming their people were too busy.

Also, 10 Investigates contacted seven pet food manufacturers in Ohio and Pennsylvania, asking to tour their facilities and tell us what they put in their pet food. Some did not get back to us. Others, like the Masterfoods plant in west Columbus, declined our request and refused to answer specific questions. Others referred 10 Investigates to the Pet Food Institute.

The lobbying group did not answer our questions either, but only said in a blanket statement that it vows 'to work tirelessly to continue our efforts to keep your pets safe and healthy...
I've noticed it's getting harder to find veterinarians willing to say that pet food is generally safe and well manufactured. They were much more confident a few weeks ago ...

On the bright side, all Chinese manufactured vegetable protein is being screened for melanine now, and no additional Chinese suppliers have yet been implicated.

Open arctic by 2020 and the Sachs Reith Lectures

The third of Sach's Reith Lectures is out today. I'm slowly listening to the the first podcast on my car "radio"; I listen a bit, turn it off, and think. I think about how the limits of the barely sentient "plains ape", the mystery of how we've survived the past 50 years, and Morford's characteristically overwrought paeon to the wisdom of the hippies.

I think about China's adamant declaration that no global warming obligations fall upon them (how like the GOP!) and again I return to Sach's radical call for a new enlightenment. The old ways are failing, he says (and I agree) -- a new way must emerge to route around the decaying structures of current governance.

I think about a recent post I read on the quiet movement to create a world parliament.

In my most hopeful moments I hope that cursed wretch, Ralph Nader, was in some meager way right to speculate that only eight years staring into the abyss would awaken America. Ralph certainly gave us a good view of the abyss.

I read this ...
The Newshoggers: Artic Ice Melt 30 Years Ahead Of Forecast - US Scientists

Reuters reports that a team of US scientists led by a glaciologist at the National Snow and Ice Center in Colorado have published a paper in the journal Geophysical Research Letters which says that the Arctic ice cap could be melting 30 years ahead of even the recent UN Intergovernmental Panel on Climate Change forecast.

This means the ocean at the top of the world could be free or nearly free of summer ice by 2020, three decades sooner than the global panel's gloomiest forecast of 2050.

No ice on the Arctic Ocean during summer would be a major spur to global warming, said Ted Scambos, a glaciologist at the National Snow and Ice Center in Colorado.

"Right now ... the Arctic helps keep the Earth cool," Scambos said in a telephone interview. "Without that Arctic ice, or with much less of it, the Earth will warm much faster."

...Scambos and co-authors of the study, published in the journal Geophysical Research Letters, used satellite data and visual confirmation of Arctic ice to reach their conclusions, a far different picture than that obtained from computer models used by the scientists of the intergovernmental panel.

"The IPCC report was very careful, very thorough and cautious, so they erred on the side of what would certainly occur as opposed to what might occur," Scambos said in a telephone interview.

... He said he had no doubt that this was caused in large part by greenhouse gases in the atmosphere, which he said was the only thing capable of changing Earth on such a large scale over so many latitudes.
Scambos isn't too optimistic about chances of holding back climate change either, saying instead that we had better start now on the changes to society needed to get through the rest of the century without humanitarian catastrophe.
Changes to the social order. That's what Sachs is calling for. It's a lot to ask of hacked wetware that barely runs our current dysfunctional social system.

I sure hope that "emergent hive mind" stuff works. We will need all of it.

In the meantime, write to the BBC and demand they set the Sachs lectures free as mp3s, in addition to freeing IOT.

The cost of weddings, college education, homes

I would like to see a graph of the cost of 90th percentile weddings, private college tuition, homes and family assets over the past 25 years.

My hunch is that the graph would show that they were all strongly correlated, and that the cost of 90th percentile weddings, private college tuition (at Williams [1], for example) and homes is determined primarily by available assets, not by the costs of delivering the essential functions of social union, teaching, and shelter.

I'm sure this has been done, but not being an economist I don't know how to search for it. I hope Brad DeLong will pick up the topic sometime, because it has some interesting implications. Imagine you're running a private college competing for the wealthy (who fund tuition for your talented poor). Your tuition will be cost + "profit". Your cost must cover your fixed costs (faculty, etc), but the true driver is your cost of recruitment, which manifests as recreational facilities, aesthetic experiences, etc. Since your target market has essentially unlimited resources but a limited membership, your costs of recruitment will rise until the tuition costs hits a stratospheric limit.

In evolutionary terms, this is similar to the "costs" flowers pay to attract bees.

So Harvard's full price tuition will be over $1 million within 10 years ...

[1] Highly recommended if you are poor or wealthy. I very much appreciate the wealthy students who paid for my visiting-student time there.

Wednesday, May 02, 2007

Romney and Battlefield Earth. He's so over.

Romney, who was doomed from the get-go, now announces L Ron Hubbard's Battlefield Earth is his favorite novel. This is such a bizarre choice that most commentators have been rendered speechless, but John Dickerson does his best. (The headline, alas, is as moronic as the book. Geeks read Verner Vinge, not L Ron.)

It's over. None of the current Republican "front runners" stand a chance. If the GOP picks any of them we'll know the party is choosing to retire from the field in shame. Eight years in the wilderness might just resurrect something half-respectable ...

Dyer: 7 new articles

Dyer has about seven new articles since I last visited: Israel, Asia, Gun Country (guess), the end of the war on terror, Russia, Parliament of Man and Helmand (what's that?).

He's taking donations via (yech) PayPal. I wish he'd use Amazon payments, but I'm not sure that works outside the US.

So who planted all the Iraq - al Qaeda forgeries?

Tom Tomorrow points out that Tenet's book has a rather interesting claim on page 356. US forces discovered a large cache of documents that showed al Qaeda had tight connections to Saddam. The only problem is, they were all forgeries.

So who would want to forge these documents? Who would gain if the forgery had been believed? Israel? Iran? Cheney? All of the above?

Tom asks the equally interesting question about why we're only hearing about this now.

BTW, I've a relevant post on this from 2004.

Tuesday, May 01, 2007

Five insider blogs on terrorism and warfare

Phil Carter lists five blogs five blogs that provide an "insiders" perspective on war and "counter-terrorism" (whatever terrorism is). I tried a few and rapidly learned a number of things that I don't think make it into the mainstream media. This is the "new journalism", straight and unadulterated.

Toxicity from the combination of multiple food contaminants

Melanine + cyuranic acid -> crystalline nephrophathy. Emphases mine.
Pet food contamination mystery unlocked | KOMO-TV - Seattle, Washington | News

...Scientists from Canada and the U.S. believe they may have unlocked the mystery. They've learned that melamine combined with another contaminant found in the pet food--- cyuranic acid-- forms crystals in the kidneys.

"What we've done is experiments that show if you take cat urine and you add melamine to it and cyanuric acid, the crystals will form in the cat urine in a test tube as we're watching them, so it happens within a matter of hours," Wilderman said.

The crystals are suspected of killing the pets, and the ASPCA has just seen a case that suggests that's exactly what happened.

"We had one case recently where the cats' kidneys were completely obstructed and when we went to surgery to relieve the obstruction, there was no normal stone, instead the ureters were completely full of these melamine type crystals," said Dr. Louise Murray, with the ASPCA Animal Hospital...
One wonders how many different contaminants have been introduced into the Chinese supplied pet food ingredients. The list keeps growing. I missed this story yesterday, but Google already has over 200 hits on the topic.