Sunday, December 26, 2010

New experiment. Interesting science on this date.

I'm trying something new to get me writing more often.  This new experiment is to try to write something about some interesting science that occurred on the given date.  I want to post something every weekday, but suspect that may be too much.  We'll see.

26 December:

26 December 2004, the Sumatra-Andaman earthquake rocked Indonesia, Sumatra, India, Thailand, etc.  This quake had a seismic moment magnitude of between 9.1 and 9.3.  The resulting tsunami caused more than 283,000 deaths directly, though I suspect the full casualty count is closer to one million if you count the continuing problems associated with this earthquake and resulting tsunami.

The seismic moment magnitude is what scientists use as a replacement for the Richter magnitude.  This is a dimensionless number given by:

Mw = 2/3 log(M0) - 10.7.

The constants used are to give numbers consistent with the old Richter scale, so if you hear someone quote the magnitude "on the Richter scale", realize that it's similar but not really the same, and they're probably wrong--all earthquakes now are measured using the seismic moment magnitude scale.  An increase of one step in this scale corresponds to 10^1.5 = 32 times increase in amount of energy released.  Two steps corresponds to 10^3 = 1000 times increase in energy.

The Loma Prieta earthquake, in 1989, that affected the Bay area measured 6.9 on the moment magnitude scale.

6.9 to 9.3 is 2.4 steps or about a factor of 4,000 on this scale.
You can check this using WolframAlpha.
The Sumatra-Andaman earthquake had an equivalent energy release of 3.7x10^20 Joules.

The Loma Prieta earthquake had an equivalent energy release of 9.3x10^16 Joules.

That is, the Sumatra-Andaman earthquake was about 4,000 times as energetic as the Loma Prieta earthquake.

To get you thinking about the energy release of this earthquake, try this:  Little boy and Fat man, the nuclear bombs dropped on Japan during WWII had yields between 5x and 9x10^13 Joules.  The Loma Prieta earthquake was about 1,000 times as energetic as the bomb dropped on Nagasaki, and the Sumatra-Andaman earthquake was another 4,000 times as energetic as that.  Of course, the energy from the nuclear bomb was much more concentrated than the earthquakes'.

The Sumatra-Andaman is the earthquake that awakened the world to the need for tsunami warning systems.

The spacecraft Jason 1 detected the 1-meter trough-to-crest wave of the resulting tsunami 1500 km south of Sri Lanka.  That's right, the 3- to 11-meter tsunami that hit Sri Lanka was only about 1-meter trough-to-crest in the ocean.  In Thailand, the largest tsunami height was 19.6 meters, though most heights measured less than 10 meters.

Tuesday, November 30, 2010

Vitamin D in the news

The report from the National Academies (it's behind a paywall, so I'm not going to waste your time by linking to it) on vitamin D and calcium has been in the news today.

What's surprising is that the headlines are so very different.  Okay, that's not really surprising, given the poor quality of writing, reading, and investigation that passes for journalism in this country.

WaPo:  New vitamin D recommendations

Bloomberg: Vitamin D, Calcium Supplements Are Unnecessary, Study Finds

WSJ: Triple That Vitamin D Intake, Panel Prescribes

AP: Report: A bit more vitamin D is good, not too much

NPR: Medical Panel: Don't Go Overboard On Vitamin D

USA Today: Most getting enough calcium, vitamin D, report says

Science News: Vitamin D targets increased

NYTimes: Report Questions Need for 2 Diet Supplements

WebMD: Guidelines Call for Increase in Vitamin D

What's going on?

Well, as I said, not very many of these reporters seem to be reading their scientific sources very well.

At the bottom is the actual news release from the National Academies.  I was able to find a poor-quality scan of the report that isn't behind a paywall.  There is also a report brief here.

From that, here's the table for recommended total calcium and vitamin D intake:

To be honest, about all the news organizations had to report to do a good job was the new recommended intake for both calcium and vitamin D and the fact that girls 14-18 are not getting enough calcium.  Instead, most of them misinterpreted the report or the NAS news release in favor of some over-the-top scare headlines.

WaPo:  C- (missed the conclusion that girls 14-18 are not getting enough calcium)
Bloomberg: D- (misinterpreted the report and concluded that people should stop taking supplements)
WSJ: (Headline is misleading, reports that infants should be receiving 600 IUs, ignored calcium)
AP: C- (Headline is appropriate, missed some important conclusions, ignored calcium)
NPR: C- (Appropriate headline, ignored calcium, missed important conclusions)
USAToday: B- (hit the highlights, gave too much voice to people who advocate way too much D)
Science News: D- (fine headline, but then spent most of the article quoting people who advocate too much D, ignored calcium)
NYTimes: F I can't read the article because of their registration wall.  Their headline is flat-out wrong.
WEbMD: B (hit the highlights, decent headline)

News from the National Academies
Nov. 30, 2010


IOM Report Sets New Dietary Intake Levels for Calcium and Vitamin D To Maintain Health and Avoid Risks Associated With Excess

WASHINGTON — Most Americans and Canadians up to age 70 need no more than 600 international units (IUs) of vitamin D per day to maintain health, and those 71 and older may need as much as 800 IUs, says a new report from the Institute of Medicine.  The amount of calcium needed ranges, based on age, from 700 to 1,300 milligrams per day, according to the report, which updates the nutritional reference values known as Dietary Reference Intakes (DRIs) for these interrelated nutrients. 

The report's recommendations take into account nearly 1,000 published studies as well as testimony from scientists and stakeholders.  A large amount of evidence, which formed the basis of the new intake values, confirms the roles of calcium and vitamin D in promoting skeletal growth and maintenance and the amounts needed to avoid poor bone health.  The committee that wrote the report also reviewed hundreds of studies and reports on other possible health effects of vitamin D, such as protection against cancer, heart disease, autoimmune diseases, and diabetes.  While these studies point to possibilities that warrant further investigation, they have yielded conflicting and mixed results and do not offer the evidence needed to confirm that vitamin D has these effects.  Rigorous trials that yield consistent results are vital for reaching conclusions, as past experiences have shown.  Vitamin E, for example, was believed to protect against heart disease before further studies disproved it.

"There is abundant science to confidently state how much vitamin D and calcium people need," said committee chair Catharine Ross, professor and Dorothy Foehr Huck Chair, department of nutritional sciences, Pennsylvania State University, University Park.  "We scrutinized the evidence, looking for indications of beneficial effects at all levels of intake.  Amounts higher than those specified in this report are not necessary to maintain bone health." 

The science on calcium's role in bone health shows that 700 milligrams per day meets the needs of almost all children ages 1 through 3, and 1,000 milligrams daily is appropriate for almost all children ages 4 through 8. Adolescents ages 9 through 18 require no more than 1,300 milligrams per day.  For practically all adults ages 19 through 50 and for men until age 71, 1,000 milligrams covers daily calcium needs.  Women starting at age 51 and both men and women age 71 and older need no more than 1,200 milligrams per day. 

As for vitamin D, 600 IUs daily meets the needs of almost everyone in the United States and Canada, although people 71 and older may require as much as 800 IUs per day because of potential physical and behavioral changes related to aging. 

The majority of Americans and Canadians are getting enough vitamin D and calcium, the committee determined from reviewing national surveys of blood levels.  Some adolescent girls may not get quite enough calcium, and there is a greater chance that elderly individuals may fall short of the necessary amounts of calcium and vitamin D.  These individuals should increase their intake of foods containing these nutrients and possibly take a supplement.

Confusion about the amount of vitamin D necessary to ward off deficiency has arisen in recent years as tests that measure levels in patients' blood have become widely used.  The measurements of sufficiency and deficiency — the cutpoints — that clinical laboratories use to report test results have not been based on rigorous scientific studies and are not standardized.  This lack of agreement means the same individual could be declared deficient or sufficient depending on which laboratory reads the test.  There may be an overestimation of the number of people with vitamin D deficiency because many labs appear to be using cutpoints that are higher than the evidence indicates are appropriate.  Based on available data, almost all individuals get sufficient vitamin D when their blood levels are at or above 20 nanograms per milliliter as it is measured in America, or 50 nanomoles per liter as measured in Canada

Although sunlight triggers the natural production of vitamin D in skin and contributes to people's vitamin D levels, individuals' sun exposure varies greatly and many people are told to minimize their exposure, so the committee assumed minimal sun exposure to establish the DRIs.  The new intake levels for vitamin D cover the needs of individuals who get little sun. 

Greater amounts of food fortification and rising rates of supplement use have increased the chances that people consume high amounts of these nutrients.  Getting too much calcium from dietary supplements has been associated with kidney stones, while excessive vitamin D can damage the kidneys and heart.  Evidence about other possible risks associated with routine vitamin D supplementation is still tentative, and most studies have focused on very high doses taken short term rather than on routine, long-term consumption of large amounts.  However, some signals suggest there are greater risks of death and chronic disease associated with long-term high vitamin D intake, which informed the committee's conclusions about levels that consumers should not exceed. 

Upper intake levels represent the upper safe boundary and should not be misunderstood as amounts people need or should strive to consume.  The upper intake levels for vitamin D are 2,500 IUs per day for children ages 1 through 3; 3,000 IUs daily for children 4 through 8 years old; and 4,000 IUs daily for all others.  The upper intake levels for calcium are 2,500 milligrams per day from age 1 through 8; 3,000 milligrams daily from age 9 through 18; 2,500 milligrams daily from age 19 through 50; and 2,000 milligrams per day for all other age groups. 

"While it is too early to make definitive statements about the risks associated with routine high doses of vitamin D and calcium, people don't need more than the amounts established in this report," Ross said.  "Past cases such as hormone replacement therapy and high doses of beta carotene remind us that some therapies that seemed to show promise for treating or preventing health problems ultimately did not work out and even caused harm.  This is why it is appropriate to approach emerging evidence about an intervention cautiously, but with an open mind."

The new DRIs are based on much more information and higher-quality study results than were available when the DRIs for these nutrients were first set in 1997.  At that time, limitations in the evidence resulted in intake levels called Adequate Intakes, which are rougher estimations of people's requirements than the new values.  The old and new DRIs reflect different calculations and are not directly comparable.

The study was sponsored by the U.S. Department of Health and Human Services, U.S. Department of Agriculture, U.S. Department of Defense, and Health Canada.  Established in 1970 under the charter of the National Academy of Sciences, the Institute of Medicine provides independent, objective, evidence-based advice to policymakers, health professionals, the private sector, and the public.  The National Academy of Sciences, National Academy of Engineering, Institute of Medicine, and National Research Council make up the National Academies.  For more information, visit  A committee roster follows.

Christine Stencel, Senior Media Relations Officer
Christopher White, Media Relations Assistant
Office of News and Public Information
202-334-2138; e-mail

Sunday, October 17, 2010

The Swiss to the Alps: Resistance is Futile.

World record on the Gotthard: The longest railway tunnel in the world has become a reality. On 15 October 2010 in the east tunnel, 30-km from the north portal and 27-km from the south portal, the final breakthrough of the Gotthard took place. At about 14:30, the tunnel boring machine, drilling from Faido, broke through the last metre of rock on the route to Sedrun.
The tunnel breakthrough was highly accurate. At 8 cm horizontally and 1 cm vertically, the deviation was very small. [My emphasis].

The Swiss just finished drilling a 57-km long tunnel through the Alps, and were off their target by 8 cm!  3 inches!  After drilling through 30-km of rock, they missed their target by about the width of your hand.

Wednesday, September 29, 2010

First exoplanet within the habitable zone (and also earth-like density)

I'm going to quote the press release below, but first let me say that this is awesome.  Now, we've got absolutely no evidence for anything living there yet, but, what we do have is:

  •  A rocky planet with enough mass to maintain an atmosphere.
  • A rocky planet a distance from its sun that puts it within the zone where liquid water, solid water, and gaseous water may all exist at the same time.
  • A rocky planet with one side tidally locked to its star.
What does this mean?  Well, if the planet has enough mass to maintain an atmosphere, the only reason it WOULDN'T maintain an atmosphere is if its star stripped it away through certain kinds of activity; the star, though, is massive enough that it's not really the type to have many flares, so it's probable that there is an atmosphere on this planet.

The planet is close enough to the star that its year is only 37 earth-days long.  That's closer than Mercury to our sun.  However, our sun is not a red dwarf like Gliese 581.  This means that Gliese 581's luminosity is much lower than our sun's--a planet would need to be a lot closer to the star to be in its habitable zone.  It also means that---I'm being sci-fi here---if life has evolved on this planet, and life also evolved complex organs, including eyes, the beings there would see at a different wavelength from us.  Neat!

Additionally, due to the tidal-locking (very similar to how we only ever see one face of the moon), 1/2 of the body would be always in shadow (cold) and 1/2 of the body would always be in light (warm/hot).  This means that there would be a narrow strip along what's called the terminator (although it doesn't exactly apply when a body has an atmosphere)--the boundary between night and day--that would be the ideal habitat for any creatures living on this planet.  There have been some interesting short short stories about such places, though I can't remember their names or their authors, so you'd have to go look for them yourself.

Anyway, it's pretty cool that we're now able to find planets that are only 3-4 times as massive as our home...  Soon, we should be able to say what kind of atmosphere these planets have, and then we should be able to argue whether or not they have any kind of life on them...
NASA and NSF-Funded Research Finds First Potentially Habitable Exoplanet
WASHINGTON -- A team of planet hunters from the University of California (UC) Santa Cruz, and the Carnegie Institution of Washington has announced the discovery of a planet with three times the mass of Earth orbiting a nearby star at a distance that places it squarely in the middle of the star's "habitable zone." 

This discovery was the result of more than a decade of observations using the W. M. Keck Observatory in Hawaii, one of the world's largest optical telescopes. The research, sponsored by NASA and the National Science Foundation, placed the planet in an area where liquid water could exist on the planet's surface. If confirmed, this would be the most Earth-like exoplanet yet discovered and the first strong case for a potentially habitable one. 

To astronomers, a "potentially habitable" planet is one that could sustain life, not necessarily one where humans would thrive. Habitability depends on many factors, but having liquid water and an atmosphere are among the most important. 

The new findings are based on 11 years of observations of the nearby red dwarf star Gliese 581using the HIRES spectrometer on the Keck I Telescope. The spectrometer allows precise measurements of a star's radial velocity (its motion along the line of sight from Earth), which can reveal the presence of planets. The gravitational tug of an orbiting planet causes periodic changes in the radial velocity of the host star. Multiple planets induce complex wobbles in the star's motion, and astronomers use sophisticated analyses to detect planets and determine their orbits and masses. 

"Keck's long-term observations of the wobble of nearby stars enabled the detection of this multi-planetary system," said Mario R. Perez, Keck program scientist at NASA Headquarters in Washington. "Keck is once again proving itself an amazing tool for scientific research." 
Steven Vogt, professor of astronomy and astrophysics at UC Santa Cruz, and Paul Butler of the Carnegie Institution lead the Lick-Carnegie Exoplanet Survey. The team's new findings are reported in a paper published in the Astrophysical Journal and posted online at: 

"Our findings offer a very compelling case for a potentially habitable planet," said Vogt. "The fact that we were able to detect this planet so quickly and so nearby tells us that planets like this must be really common." 

The paper reports the discovery of two new planets around Gliese 581. This brings the total number of known planets around this star to six, the most yet discovered in a planetary system outside of our own. Like our solar system, the planets around Gliese 581 have nearly-circular orbits. 

The new planet designated Gliese 581g has a mass three to four times that of Earth and orbits its star in just under 37 days. Its mass indicates that it is probably a rocky planet with a definite surface and enough gravity to hold on to an atmosphere. 
Gliese 581, located 20 light years away from Earth in the constellation Libra, has two previously detected planets that lie at the edges of the habitable zone, one on the hot side (planet c) and one on the cold side (planet d). While some astronomers still think planet d may be habitable if it has a thick atmosphere with a strong greenhouse effect to warm it up, others are skeptical. The newly-discovered planet g, however, lies right in the middle of the habitable zone. 

The planet is tidally locked to the star, meaning that one side is always facing the star and basking in perpetual daylight, while the side facing away from the star is in perpetual darkness. One effect of this is to stabilize the planet's surface climates, according to Vogt. The most habitable zone on the planet's surface would be the line between shadow and light (known as the "terminator"). 

Monday, July 19, 2010

We Are all Going to Die of Heart Failure Because we Sit at Desks for Eight Hours a Day!!!! Wait, Whatever Happened to Fact Checking?

A friend of mine shared this link via Google Reader. This is Kottke's reading of the New York Time's complete bungling of a medical report published in Medicine & Science in Sports & Exercise. This bungling is so bad that I'm inspired to rant (okay, just about anything inspires me to rant, but this seemed an appropriate forum for this rant).

Kottke read the NYTimes article and didn't actually follow through to read, in any more detail, the actual report.  They're at fault for just blindly reading something from NYTimes without checking it out.  They're at fault for then publishing what they read as fact, and for quoting an "authority" without making sure what they read was from the original source.

NYTimes is just plain wrong.  They apparently couldn't read to the end of the abstract before running off to be the ones with the scoop.  From their article, one would have to assume that those of us with desk jobs are doomed to die from Cardiovascular disease (CVD), no matter how much we exercise at other times.

I don't have access to the full article, unless I want to pay some ridiculous fee.  However, the abstract is freely available here.  The results and conclusions sections of the abstract are reproduced below, with my emphasis added.  Since I don't actually do any physical activities other than type, I'm pretty much doomed, but those of you who exercise for health reasons, don't stop just because some dumb reporter can't read to the end of a page.

Results: Three hundred and seventy-seven CVD deaths occurred during 21 yr of follow-up. After age adjustment, time riding in a car and combined time spent in these two sedentary behaviors were positively (Ptrend < 0.001) associated with CVD death. Men who reported >10 h·wk−1 riding in a car or >23 h·wk−1 of combined sedentary behavior had 82% and 64% greater risk of dying from CVD than those who reported >4 or >11 h·wk−1, respectively. The pattern of the association did not materially change after multivariate adjustment. Regardless of the amount of sedentary activity reported by these men, being older, having normal weight, being normotensive, and being physically active were associated with a reduced risk of CVD death.

Conclusion: In men, riding in a car and combined time spent in these two sedentary behaviors were significant CVD mortality predictors. In addition, high levels of physical activity were related to notably lower rates of CVD death even in the presence of high levels of sedentary behavior. Health promotion efforts targeting physically inactive men should emphasize both reducing sedentary activity and increasing regular physical activity for optimal cardiovascular health.

Monday, June 7, 2010

Extraterrestrial life? Not Based on Water?

Ars Technica, a geek news site has an article pulling a sentence out of an abstract about the chemistry on Saturn's moon Titan.  They latch onto the idea that certain chemical processes producing some weird abundances in Titan's atmosphere could be caused by a methanogenic life form.  Methanogenic here means based on methane as the solvent rather than water as the solvent.  This idea has been around for a while, and is perfectly reasonable.

Of course, the peculiar abundances could be caused by some simple chemistry and most of the scientific article discusses that simple chemistry, but why would a geek news site that thrives on far-out ideas write an entire article discussing the possibility of simple chemistry when it can talk about our new overlords from Titan?

Regardless, it's still interesting.  And I'm still wishing I was asleep instead of blogging at 7:32 Eastern Daylight Time (4:32 My Body's Standard Time), but I've got to get going to crush more young researcher's dreams of pauperdom and drive them into industry where money is easier to come by.

Thursday, February 4, 2010

What's the Big Deal About Toyota's Cars?

I need someone to explain this to me:  There have been something like a few thousand reports of sudden unintended acceleration on all of the ~30 million Toyota vehicles sold since 1999.  That's something like 0.00667%.  Let's be generous and say there are 10x as many problems as reported.  That's still 0.06667%.  That is, there are about 70 incidents for 100,000 vehicles, with a much lower rate of injury and even lower rate of death.

Why are we wasting our time on this but not bothering to deal with real problems?  What are we doing to fix human-induced climate change?  What are we doing to fix problems with access to clean water?  What are we doing to fix the 40,000 gun-related murders in the US every year?  What are we doing to deliver better, cheaper health care to our citizens?  What are we doing about Darfur?  What are we doing about the five million people injured or killed due to alcohol-related vehicular accidents?

In short, why is everyone freaking out about such an irrelevant "problem" when there are real problems to deal with?