INL Science Feature: INL scientists help harness bacteria power to brew eco-friendly plastic from waste

Three samples of premium wood-plastic composite lumber sit in a stack on a shelf in David Thompson's office at Idaho National Laboratory. The dense, fine-grained boards are uniformly colored in shades that range from light to dark brown.

All three boards match each other in strength and durability. But one of the boards has two special ingredients: plastic made by bacteria, and the same harmless bacteria that made the plastic — by eating wastewater.

Eat more food than you can use, and your body will stockpile the surplus in all sorts of curvaceous and unsightly ways. Many species of bacteria do something similar.

"Plastic, to these bacteria, is like fat," says Thompson, an INL biochemical engineer. Given an abundance of sugars, alcohols or other simple carbon sources, the bacteria will ferment the molecules for energy and string together the leftovers into long chains, or polymers, that they can stash for use in leaner times. Many of these polymers are actually types of plastic called polyhydroxyalkanoates, or PHA for short.

What bacteria make, they can also break down. All three of the sample composite boards in Thompson's office are too dense to absorb much water, which helps them resist rotting and cracking better than natural wood. But if you chipped up Thompson's bacteria-PHA composite board and buried it in an active compost pile, it would biodegrade completely in three to six months. In contrast, the petroleum-based plastics in standard wood-plastic composites could sit in your backyard or in a landfill for hundreds of years or more before breaking down completely.

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For fun: Asians and blacks - the extremes in interracial marriage

This is a follow-up on a NYTimes story, Black Women See Fewer Black Men at the Altar. The range and extremes in this cursory analysis of interracial marriage rates are pretty striking:

Of all 3.8 million adults who married in 2008, 31 percent of Asians, 26 percent of Hispanic people, 16 percent of blacks and 9 percent of whites married a person whose race or ethnicity was different from their own. Those were all record highs.

Well, since Asians are the smallest ethnic group of the four, just by sheer odds we should be marrying outside our race ('marrying out') more often than the other groups. But how many of the interracial marriages are due to preference and how many of them are what we would expect just by the numbers?

If your choice of whom to marry were completely independent of race, the chance that you'll marry someone from another race would be about like the chance you'll run into someone from that race on the street. If we take the U.S. Census Bureau data from 2004 (most contemporary survey with all four of the largest races), the single (not married or separated) population over age 15 is:

3.6% Asian
13.3% Hispanic
16.5% black, and
66.5% white.

So since 96 of every 100 single people (13.3+16.5+66.5 = about 96) in the States are not Asian, you'd expect about 96 of every 100 Asians to marry out.

But only 31 of each 100 did, so it looks like Asians show some tendency to marry each other ('marry in') more than they marry out. Let's look at some ratios to see how the same-race preferences compare across the races:

	intermarriage rates
race	expected	/	actual	=	ratio
Asian	96.4	/	31	=	3.1
Hispanic	86.7	/	26	=	3.33
black	83.5	/	16	=	5.22
white	34.5	/	9	=	3.83

The higher the ratio, the more likely that race is to 'marry in'. Asians are, again, the biggest miscegenators, but not by a lot. Blacks, on the other hand, are far more likely than the other racial groups to marry each other based on what we would expect from race-independent marriage. We can speculate on the contributing factors - prejudice, prison, education, age structure, other socioeconomics - but I don't have any data to support or refute any of them for now.

By the way, in 2004, the percentage of each racial group married without separation:

Asians 61%
Hispanics 50%
blacks 34%
whites 57%.

Asians are almost twice as likely to be married as blacks.

[In a New York Jewish accent] Talk amongst yourselves.

WHERE I GOT MY NUMBERS:

In addition to the referenced NYT story, I pulled March 2004 Census Bureau Community Survey data from these sources:

http://www.census.gov/population/socdemo/race/api/ppl-184/tab2.html
http://www.census.gov/population/socdemo/hispanic/ASEC2004/2004CPS_tab2.1.html
http://www.census.gov/population/socdemo/race/black/ppl-186/tab2.html

From those tables I added the numbers of widowed, divorced, and never married to get the following numbers:

3,623,000 single asians >15 both sexes in March 2004
13,294,000 single hispanics >15 both sexes in March 2004
16,499,000 single blacks >15 both sexes in March 2004
66,408,000 single whites > 15 both sexes in March 2004
99,824,000 single people total in March 2004

The percentages of each racial group that are married are taken directly from the linked tables. Yes, I am leaving out Inuit/American Indian, Hawaiians and other Pacific Islanders, as well as mixed-race. They account for, respectively, 0.8%, 0.14%, and 2.3% of the population, too small a percentage for the CB to have useful data on them.

AGU blog posts: water resources

My blog posts from the American Geophysical Union fall meeting, an annual gathering of more than 16,000 earth and space scientists in a cavernous conference hall in downtown San Francisco:

Water, Water, Everywhere -- Except There, and There, and There

A Cold Drip: Emergency Water from the Air

in the style of New Scientist

New gamma-ray eyes spot hidden pulsars

NASA’s new Fermi gamma-ray telescope has captured the faint gamma-ray glimmer of pulsars invisible to radio telescopes. The enhanced ability to detect pulsars may help theorists flesh out the life stories of massive stars.

Pulsars are spinning neutron stars, the dense and fiercely magnetized remnants of massive stars that underwent gravitational collapse. Astronomers can observe them with a radio telescope only when the slender streams of radio waves broadcast from their magnetic poles point Earthward. The newly identified pulsars appear to emit gamma-rays in broad plumes originating in their intense magnetic atmospheres well above the neutron stars’ surfaces.

The new pulsars weren’t simple to spot. To detect periodic patterns in emissions from extremely faint objects rotating at an unknown rate, a team led by the Santa Cruz Institute for Particle Physics (SCIPP) ran five months of data through a series of brute force guess-and-check calculations. Their computations turned up 16 pulsars rotating between 2 and 20 times per second (Science, DOI: 10.1126/science.1175558). Since then, they have identified at least 8 more. The newly discovered pulsars are 10,000 to 100,000 years old, young by astronomical standards.

“Certainly there are a lot that we haven’t seen,” says Robert Johnson, the SCIPP physicist who designed the telescope’s gamma-ray sensors. Astronomers have already identified more than 1800 radio pulsars, but Johnson said the new gamma-ray telescope may double the number of pulsars they can detect.

Caption: New pulsars: blink and you’ll miss them.

soft lede exercise

SANTA CRUZ - In Jacob Rosen’s operating room, the nurses might quit if they stray too far from the wall sockets.

In a videotaped demonstration of Rosen’s robotic operating room, two robotic arms stitched and snipped sutures across a wound on the patient’s torso. Rosen pointed at a third arm as it retrieved a tool and passed it to one of the surgeon arms.

“This is the nurse, by the way,” said Rosen.

The UC Santa Cruz computer engineer is making real surgery look more like the surgery in video games and science fiction movies.

in the style of Smithsonian's Wild Life

Timed Flight

How do tiny monarch butterflies migrate more than 2,000 miles without a map and end up in the same grove of fir trees in central Mexico, year after year? They navigate by the sun, just as the Vikings did. The monarchs’ internal sun compass needs a clock to work correctly because the sun is “a moving target, and butterflies need to compensate for that movement,” says Steven Reppert of the University of Massachusetts. Until recently, scientists assumed that butterflies navigated with a light-sensitive clock built into their brains. Reppert and his colleagues discovered that monarchs have two such clocks – and that they navigate with the one in their antennae.

The researchers put tiny leashes on the monarchs and let them take wing in an outdoor flight simulator. Normal butterflies flew southwest, toward Mexico. Butterflies with their antennae snipped off couldn’t orient properly and took off every which way. Painting the monarchs’ antennae black didn’t affect their brain clocks, but a few days without time cues from the sun set the butterflies and their antenna clocks adrift. Bees, ants, and other insects that navigate by the sun may rely on antenna clocks, too.

News: tsunami science

A story of watery destruction, written in sand

SANTA CRUZ – Mention the word “tsunami,” and many people envision a towering wall of water. But according to U.S. Geological Survey oceanographer Bruce Jaffe, tsunamis don’t have to be very tall to be deadly.

“Once it starts getting above your knees, you’re in trouble,” Jaffe said.

On Sept. 29, an underwater earthquake sent a series of massive waves hurtling toward the South Pacific island of Samoa. When the tsunami slammed into the coast and surged ashore, it knocked down trees, buildings, and people, hauling away the wreckage with terrible speed.

Jaffe was fresh from a research trip to the tsunami aftermath when he lectured about it to a UC Santa Cruz audience Tuesday afternoon. He was still reeling from the destruction and human toll, which the Associated Press reported at more than 160 dead.

Tsunami education and evacuation drills paid off for Samoans, Jaffe said. On the day of the tsunami, children waiting for the school bus noticed the water receding. The children recognized the classic tsunami sign and persuaded adults to sound an alarm. Many residents were able to evacuate to the safety of high ground before the tsunami hit.

“The good news is that nearly everywhere on the island, people knew about tsunamis,” Jaffe said. “Had there not been that knowledge, I think there would be probably several thousand if not more people who got killed.”

Jaffe and his colleagues are adding to the body of tsunami knowledge with their research on tsunami sand deposits. They learned that sand particles can ride tsunamis a half mile or more inland before settling out into deposits. They can measure how far inland the sand travels and use that figure to estimate the speed and depth of the waves as well as the strength of the earthquake that produced them.

Jaffe and his colleagues know a tsunami deposit when they see one. The deposits are typically a few inches to one foot deep, and often contain chunks of dirt torn up by the powerful waves. In some cases they may be preserved for millions of years as sandstone.

The oldest tsunami deposit ever found is 65 million years old, Jaffe said. It may have been set off by the same asteroid impact that caused the extinction of many dinosaurs.

More tsunami history may be recorded in sandstone deposits buried in our own backyards, Jaffe said. Using those deposits to fill in the gaps in our patchy tsunami records can help scientists construct a tsunami forecast.

“People don’t believe that a tsunami’s going to hit them,” Jaffe said. “But then when they see the deposit and you show them, here’s what a modern tsunami deposit looks like and this looks very similar, then they pay attention.”