Category Archives: Science

Top Countries for Science and Math Education: Finland, Hong Kong and Korea

The 2009 Programme for International Student Assessment (PISA)* report has been released. The report examines the science of 15 year olds from 57 countries in math, science and reading. The main focus of PISA 2009 was reading. The survey also updated performance assessments in mathematics and science.

The Asian countries continue to do very well for several reason including tutoring; they have even turned tutors into rock stars earning millions of dollars. The results show that the focus on student achievement in sciences has had an impact in Asia.

The emphasis is on mastering processes, understanding concepts and functioning in various contexts within each assessment area. the PISA 2012 survey will return to mathematics as the major assessment area, PISA 2015 will focus on science.

Results for the Science portion (rank – country – mean score)(I am not listing all countries):

1 – Finland – 554
2 – Hong Kong – 549
3 – Japan – 539
4 – Korea – 538
5 – New Zealand – 532
6 – Canada – 529
7 – Estonia – 528
8 – Australia – 527
9 – Netherlands – 522
10 – Taiwan – 520
11 – Germany – 520
14 – United Kingdom – 514
21 – USA – 502 (up from 489 and 29th place in 2006)
OECD average – 501
25 – France – 498
46 – Mexico – 416
49 – Brazil – 405

Results for the math portion (rank – country – mean score)(I am not listing all countries):
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Scientific Inquiry: Arsenic for Phosphorus in Bacteria Cells

As would be expected with significant new scientific claims, scientists are examining the evidence. On her blog, Rosie Redfield, who runs a microbiology research lab in the Life Sciences Centre at the University of British Columbia, disputes NASA’s recent claims. This is how science is suppose to work. Scientists provide evidence. Other scientists review the evidence, try to verify the claims with experiments of their own and the scientific inquiry process moves toward new knowledge.

Arsenic-associated bacteria (NASA’s claims)

NASA’s shameful analysis of the alleged bacteria in the Mars meteorite made me very suspicious of their microbiology, an attitude that’s only strengthened by my reading of this paper. Basically, it doesn’t present ANY convincing evidence that arsenic has been incorporated into DNA (or any other biological molecule).
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The authors then grew some cells with radioactive arsenate (73-As) and no phosphate, washed and dissolved them, and used extraction with phenol and phenol:chloroform to separate the major macromolecules. The protein fraction at the interface between the organic and aqueous phases had about 10% of the arsenic label but, because the interface material is typically contaminated with liquid from the aqueous phase, this is not good evidence that the cells’ protein contained covalently-bound arsenate in place of phosphorus. About 75% of the arsenic label was in the ‘supernatant ‘fraction. The authors describe this fraction as DNA/RNA, but it also contains most of the small water-soluble molecules of the cell, so its high arsenic content is not evidence that the DNA and RNA contain arsenic in place of phosphorus. The authors use very indirect evidence to argue that the distribution of arsenic mirrors that expected for phosphate, but this argument depends on so many assumptions that it should be ignored.
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I don’t know whether the authors are just bad scientists or whether they’re unscrupulously pushing NASA’s ‘There’s life in outer space!’ agenda. I hesitate to blame the reviewers, as their objections are likely to have been overruled by Science’s editors in their eagerness to score such a high-impact publication.

New claims have to provide strong evidence. time will tell if this discovery is actually a discovery. It will be amazing if it is, so I am pulling for it. But the story will need to have much more confirmation before we can be certain.

Arsenate-based DNA: a big idea with big holes

The study published in Science has a number of flaws. In particular, one subtle but critical piece of evidence has been overlooked, and it demonstrates that the DNA in question actually has a phosphate – not an arsenate -backbone.
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Wolfe-Simon et al. used a technique called nanoSIMS to analyze elemental concentrations of the agarose gel at the location of the DNA band. They determined that the part of the gel containing DNA also contained both arsenic and phosphorus. But what did they really analyze?

The answer is that the nanoSIMS determined the concentration of arsenic in the gel – not specifically in the DNA.
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Finally, there’s a simple experiment that could resolve this debate: analyze the nucleotides directly. Show a mass spectrum of DNA sequences demonstrating that nucleotides contain arsenate instead of phosphate. This is a very simple experiment, and would be quite convincing – but it has not been performed.

Changing Life as We Know It

Update: Independent researchers find no evidence for arsenic life in Mono Lake

NASA has made a discovery that changes our understanding of the very makeup of life itself on earth. I think my favorite scientific discipline name is astrobiology. NASA pursues a great deal of this research not just out in space but also looking at earth based life. Their astrobiology research has changed the fundamental knowledge about what comprises all known life on Earth.

Felisa Wolfe-Simon processing mud from Mono Lake to inoculate media to grow microbes on arsenic.

Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth. Phosphorus is part of the chemical backbone of DNA and RNA, the structures that carry genetic instructions for life, and is considered an essential element for all living cells.

Phosphorus is a central component of the energy-carrying molecule in all cells (adenosine triphosphate) and also the phospholipids that form all cell membranes. Arsenic, which is chemically similar to phosphorus, is poisonous for most life on Earth. Arsenic disrupts metabolic pathways because chemically it behaves similarly to phosphate.

Researchers conducting tests in the harsh, but beautiful (see photo), environment of Mono Lake in California have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism substitutes arsenic for phosphorus in its cell components.

“The definition of life has just expanded,” said Ed Weiler, NASA’s associate administrator for the Science Mission Directorate. “As we pursue our efforts to seek signs of life in the solar system, we have to think more broadly, more diversely and consider life as we do not know it.” This finding of an alternative biochemistry makeup will alter biology textbooks and expand the scope of the search for life beyond Earth.

In science such huge breakthroughs are not just excepted without debate, however, which is wise.

Thriving on Arsenic:

In other words, every experiment Wolfe-Simon performed pointed to the same conclusion: GFAJ-1 can substitute arsenic for phosphorus in its DNA. “I really have no idea what another explanation would be,” Wolfe-Simon says.

But Steven Benner, a distinguished fellow at the Foundation for Applied Molecular Evolution in Gainesville, FL, remains skeptical. If you “replace all the phosphates by arsenates,” in the backbone of DNA, he says, “every bond in that chain is going to hydrolyze [react with water and fall apart] with a half-life on the order of minutes, say 10 minutes.” So “if there is an arsenate equivalent of DNA in that bug, it has to be seriously stabilized” by some as-yet-unknown mechanism.

It is sure a great story if it is true though. Other scientists will examine more data and confirm or disprove the claims.

“We know that some microbes can breathe arsenic, but what we’ve found is a microbe doing something new — building parts of itself out of arsenic,” said Felisa Wolfe-Simon, a NASA Astrobiology Research Fellow in residence at the U.S. Geological Survey in Menlo Park, Calif., and the research team’s lead scientist. “If something here on Earth can do something so unexpected, what else can life do that we haven’t seen yet?”
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Aerobic Exercise Plus Resistance Training Helps Control Type 2 Diabetes

Exercise Combo Best for Controlling Diabetes

A combination of aerobic exercise and resistance training may offer the biggest benefits for people with type 2 diabetes in helping them control their disease.
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HbA1c is a test that measures blood sugar control for the previous few months. Normal HbA1c is 6% or less. People with diabetes are urged to keep their HbA1c below 7%.

In the study, researchers compared the effects of a nine-month aerobic exercise program, a resistance training program, and combination exercise program vs. not exercising in 262 previously sedentary men and women with type 2 diabetes. The results showed that improvements in HbA1c levels were greatest among those who were in the combination group.
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Thirty-nine percent of non-exercisers had to increase these medications compared with 32% in the resistance training group, 22% in the aerobic exercise group, and 18% in the combination group.

Diabetes is a huge and growing problem. Exercise is a good strategy to remain healthy. It is best to exercise and avoid becoming sick. But if you do get diabetes then it is even more important to take care to exercise properly.

Backyard Wildlife: Robins Attack Holly Tree

Robins like to attack my holly tree and feed on the berries. Getting photos of them is hard but there are lots of them flying around all excited (I did manage to catch one of them in the photo on the left). This tree was actually here when I moved in but I also do try to nurture and add plants that feed wildlife. I like just planting things that will feed and shelter birds (and others) rather than filling bird feeders myself. There is information on how to use your backyard to promote wildlife.

Bronx High School of Nobel Prize for Physics Laureates

Bronx physics

Bronx Science owes its historic status to the fact that seven future Nobel-prize-winning physicists went through its doors – more than any other high school in the world and more than most countries have ever achieved. The school, which opened in 1938, was founded by the educator Morris Meister, who believed that if a school put bright students together, it would kindle ill-defined but valuable learning processes. The school seems to have proved him right: according to the Bronx laureates, their physics learning took place mainly outside the classroom.
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Leon Cooper, who shared the 1972 prize for work on superconductivity, recalls physics lessons as boring, and was far more enchanted by his biology classes, which lured him to stay late after school designing and running experiments “until they threw me out”. Indeed, the school’s basic-physics textbook was written by a certain Charles E Dull, whose work, though widely used in US high schools, lived up to his name. The future particle physicist Melvin Schwartz, who shared the 1988 Nobel gong, once told me his classmates’ excited discussions – not his teacher – were what first awakened his interest in physics.
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[today] the school’s most fearsome physics module – Advanced Placement Physics C – is tougher than most college-physics courses. Its dynamic instructor is Ghada Nehmeh, who was born in Lebanon and studied nuclear physics. Diminutive – smaller than most of her students – and scarf-clad, she jumps rapidly from lab table to lab table, helping piece together equipment and analyse results. Famous for being ruthlessly demanding, she tests the students on their first day by assigning them 40 calculus problems, due back the next day. “I’d never seen derivatives before,” says Kezi Cheng, a senior interested in theoretical physics. So Cheng did what most Bronx Science students do – she asked her classmates to give her a crash course on the subject. “They’re always willing to help.”

Sounds like a great place to go to school. The article also has some good anecdotes about how these students learned by seeking knowledge themselves not passively sitting and being lectured to.

Real Time Hologram Projection Getting Closer

A team led by the University of Arizona professor of Materials Science and Engineering Nasser Peyghambarian has developed a new type of holographic telepresence that allows the projection of a three-dimensional moving image without the need for special eyewear such as 3D glasses or other auxiliary devices.

“Holographic telepresence means we can record a three-dimensional image in one location and show it in another location, in real-time, anywhere in the world,” said Peyghambarian, who led the research effort.

“Holographic stereography has been capable of providing excellent resolution and depth reproduction on large-scale 3D static images,” the authors wrote, “but has been missing dynamic updating capability until now.”

The prototype device uses a 10-inch screen, but Peyghambarian’s group is already successfully testing a much larger version with a 17-inch screen. The image is recorded using an array of regular cameras, each of which views the object from a different perspective. The more cameras that are used, the more refined the final holographic presentation will appear.

The Sahara Wasn’t Always a Desert

Green Sahara

For much of the past 70,000 years, the Sahara has closely resembled the desert it is today. Some 12,000 years ago, however, a wobble in the Earth’s axis and other factors caused Africa’s seasonal monsoons to shift slightly north, bringing new rains to an area nearly the size of the contiguous United States. Lush watersheds stretched across the Sahara, from Egypt to Mauritania, drawing animal life and eventually people.
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by some 3,500 years ago the desert had returned. The people vanished.
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The twilight of the Green Sahara around 4,500 years ago might have been the perfect time to be hunting at Gobero, said Carlo Giraudi, the team’s geologist. As water sources dried up throughout the region, animals would have been drawn to pocket wetlands, making them easier to kill. Four middens found on the dunes and dated to around that time included hundreds of animal remains, as well as fish bones and clamshells—not usually part of a herder’s diet. “The Green Sahara’s climate was rapidly changing,” said Giraudi, “but just before the lake dried up, the people at Gobero would have thought they were living in a golden period.”

There are many values of science: letting our curious minds learn, giving us cool robots and gadgets and letting us learn about the past (and thus about the ever-changing world we live in).

Boa Constrictor Gives Birth to Clones

Snake gives ‘virgin birth’ to extraordinary babies

A female boa constrictor snake has given birth to two litters of extraordinary offspring. Evidence suggests the mother snake has had multiple virgin births, producing 22 baby snakes that have no father. More than that, the genetic make-up of the baby snakes is unlike any previously recorded among vertebrates, the group which includes almost all animals with a backbone.
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“All offspring are female. The offspring share only half the mother’s genetic make-up,” he told the BBC.
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Humans for example have X or Y sex chromosomes; females have two X chromosomes and males have a combination of an X and a Y chromosome. In place of X and Y, snakes and many other reptiles have Z and W chromosomes.

In all snakes, ZZ produces males and ZW produces females. Bizarrely, all the snakes in these litters were WW. This was further proof that the snakes inherited all their genetic material from their mother, as only females carry the W chromosome.

“Essentially they are half clones of their mother,” says Dr Booth. That is because the baby snakes have inherited two copies of one half of their mother’s chromosomes, including one W chromosome.
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More astonishing though, is that no vertebrate animal in which the females carry the odd sex chromosome (in this case the W chromosome) has ever been recorded naturally producing viable WW offspring via a virgin birth.

“For decades WW has been considered non-viable” says Dr Booth. In such species, all known examples of babies that are the product of parthenogenesis are male, carrying a ZZ chromosomal arrangement.

Driver Thanks Engineer Who Hit Him on Purpose

Driver thanks man who hit him on purpose

Driving to a Mariners game, Duane Innes saw a pickup ahead of him drift across lanes of traffic, sideswipe a concrete barrier and continue forward on the inside shoulder at about 40 mph. A manager of Boeing’s F22 fighter-jet program [and engineer by training], Innes dodged the truck, then looked back to see that the driver was slumped over the wheel. He knew a busy intersection was just ahead, and he had to act fast.
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“Basic physics: If I could get in front of him and let him hit me, the delta difference in speed would just be a few miles an hour, and we could slow down together,” Innes explained. So he pulled in front of the pickup, allowed it to rear-end his minivan and brought both vehicles safely to a stop in the pull-off lane.
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Some might say the driver of the truck, 80-year-old Bill Pace, of Bellevue, and anyone Pace’s truck might have slammed into had luck on their side that day. A retiree who volunteers for Special Olympics and organizes food drives, Pace didn’t know it at the time, but he’d had a minor heart attack two days earlier and his circulation was so poor he passed out at the wheel with his foot resting on the accelerator.

Nice story and nice that the article had a tiny bit of science in the story, with another example of good work by an engineer.