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Recommended posts: What Kids can Learn - Engineering the Economy - USA Under-counting Engineering Graduates - Childrens view of Scientists in England - Economics, Politics and Science Research - Phony Science Gap? - Questioning the Accuracy of Scientific Papers

Why Wasn’t the Earth Covered in Ice 4 Billion Years Ago – When the Sun was Dimmer

Climate scientists from all over the globe are now able to test their climate models under extreme conditions thanks to Professor Minik Rosing, University of Copenhagen. Rosing has solved one of the great mysteries and paradoxes of our geological past, namely, “Why the earth’s surface was not just one big lump of ice four billion years ago when the Sun’s radiation was much weaker than it is today.” Until now, scientists have presumed that the earth’s atmosphere back then consisted of 30% carbon dioxide (CO2) which ensconced the planet in a protective membrane, thereby trapping heat like a greenhouse.

The faint early sun paradox
In 1972, the late, world famous astronomer Carl Sagan and his colleague George Mullen formulated “The faint early sun paradox. ” The paradox consisted in that the earth’s climate has been fairly constant during almost four of the four and a half billion years that the planet has been in existence, and this despite the fact that radiation from the sun has increased by 25-30 percent.

The paradoxical question that arose for scientists in this connection was why the earth’s surface at its fragile beginning was not covered by ice, seeing that the sun’s rays were much fainter than they are today. Science found one probable answer in 1993, which was proffered by the American atmospheric scientist, Jim Kasting. He performed theoretical calculations that showed that 30% of the earth’s atmosphere four billion years ago consisted of CO2. This in turn entailed that the large amount of greenhouse gases layered themselves as a protective greenhouse around the planet, thereby preventing the oceans from freezing over.

Mystery solved
Now, however, Professor Minik Rosing, from the Natural History Museum of Denmark, and Christian Bjerrum, from the Department of Geography and Geology at University of Copenhagen, together with American colleagues from Stanford University in California have discovered the reason for “the missing ice age” back then, thereby solving the sun paradox, which has haunted scientific circles for more than forty years.

Professor Minik Rosing explains, “What prevented an ice age back then was not high CO2 concentration in the atmosphere, but the fact that the cloud layer was much thinner than it is today. In addition to this, the earth’s surface was covered by water. This meant that the sun’s rays could warm the oceans unobstructed, which in turn could layer the heat, thereby preventing the earth’s watery surface from freezing into ice. The reason for the lack of clouds back in earth’s childhood can be explained by the process by which clouds form. This process requires chemical substances that are produced by algae and plants, which did not exist at the time. These chemical processes would have been able to form a dense layer of clouds, which in turn would have reflected the sun’s rays, throwing them back into the cosmos and thereby preventing the warming of earth’s oceans. Scientists have formerly used the relationship between the radiation from the sun and earth’s surface temperature to calculate that earth ought to have been in a deep freeze during three billion of its four and a half billion years of existence. Sagan and Mullen brought attention to the paradox between these theoretical calculations and geological reality by the fact that the oceans had not frozen. This paradox of having a faint sun and ice-free oceans has now been solved.”

CO2 history iluminated
Minik Rosing and his team have by analyzing samples of 3.8-billion-year-old mountain rock from the world’s oldest bedrock, Isua, in western Greenland, solved the “paradox”.

But more importantly, the analyses also provided a finding for a highly important issue in today’s climate research – and climate debate, not least: whether the atmosphere’s CO2 concentration throughout earth’s history has fluctuated strongly or been fairly stable over the course of billions of years.

“The analyses of the CO2-content in the atmosphere, which can be deduced from the age-old Isua rock, show that the atmosphere at the time contained a maximum of one part per thousand of this greenhouse gas. This was three to four times more than the atmosphere’s CO2-content today. However, not anywhere in the range of the of the 30 percent share in early earth history, which has hitherto been the theoretical calculation. Hence we may conclude that the atmosphere’s CO2-content has not changed substantially through the billions of years of earth’s geological history. However, today the graph is turning upward. Not least due to the emissions from fossil fuels used by humans. Therefore it is vital to determine the geological and atmospheric premises for the prehistoric past in order to understand the present, not to mention the future, in what pertains to the design of climate models and calculations,” underscores Minik Rosing.

Full press release from the University of Copenhagen in Denmark.

Related: Sun Missing It’s SpotsSolar StormsWhy is it Colder at Higher Elevations?Magnetic Portals Connect Sun and Earth

Statistical Errors in Medical Studies

I have written about statistics, and various traps people often fall into when examining data before (Statistics Insights for Scientists and Engineers, Data Can’t Lie – But People Can be Fooled, Correlation is Not Causation, Simpson’s Paradox). And also have posted about reasons for systemic reasons for medical studies presenting misleading results (Why Most Published Research Findings Are False, How to Deal with False Research Findings, Medical Study Integrity (or Lack Thereof), Surprising New Diabetes Data). This post collects some discussion on the topic from several blogs and studies.

HIV Vaccines, p values, and Proof by David Rind

if vaccine were no better than placebo we would expect to see a difference as large or larger than the one seen in this trial only 4 in 100 times. This is distinctly different from saying that there is a 96% chance that this result is correct, which is how many people wrongly interpret such a p value.

So, the modestly positive result found in the trial must be weighed against our prior belief that such a vaccine would fail. Had the vaccine been dramatically protective, giving us much stronger evidence of efficacy, our prior doubts would be more likely to give way in the face of high quality evidence of benefit.

While the actual analysis the investigators decided to make primary would be completely appropriate had it been specified up front, it now suffers under the concern of showing marginal significance after three bites at the statistical apple; these three bites have to adversely affect our belief in the importance of that p value. And, it’s not so obvious why they would have reported this result rather than excluding those 7 patients from the per protocol analysis and making that the primary analysis; there might have been yet a fourth analysis that could have been reported had it shown that all important p value below 0.05.

How to Avoid Commonly Encountered Limitations of Published Clinical Trials by Sanjay Kaul, MD and and George A. Diamond, MD

Trials often employ composite end points that, although they enable assessment of nonfatal events and improve trial efficiency and statistical precision, entail a number of shortcomings that can potentially undermine the scientific validity of the conclusions drawn from these trials. Finally, clinical trials often employ extensive subgroup analysis. However, lack of attention to proper methods can lead to chance findings that might misinform research and result in suboptimal practice.

Why Most Published Research Findings Are False by John P. A. Ioannidis
Continue reading

Electric Wind

photo of William Kamkwamba on his windmillphoto of William Kamkwamba on his windmill from his blog.

I have written about William Kamkwamba before: Inspirational EngineerHome Engineering: Windmill for Electricity. And along with the post, Make the World Better, donated to his cause. His new book, The Boy Who Harnessed the Wind, is quite enjoyable and provides an interesting view of how he persevered. His talk of the famine, not being able to afford school and putting together a windmill using scrape parts and a few books from the library (donated by the American government – much better foreign aid than all the military weapons that are often counted as aid) is inspirational. And should help many sitting in luxury understand the privileged lives they lead.

“I’d become very interested in how things worked, yet never thought of this as science. In addition to radios, I’d also become fascinated by how cards worked, especially how petrol operated an engine. How does this happen? I thought? Well, that’s easy to find out – just ask someone with a car… But no one could tell me… Really how can you drive a truck and not know how it works?” (page 66)

“Using Energy, and this book has since changed my life… All I needed was a windmill, and then I could have lights. No more kerosene lamps that burned out eyes… I could stay awake at night reading instead of going to bed at seven with the rest of Malawi. But most important, a windmill could also rotate a pump for water and irrigation.” (page 158)

William set out to demonstrate his windmill for the first time to a skeptical crowd saying (page 193)

“Let’s see how crazy this boy really is.”… “Look,” someone said. “He’s made light!”… “Electric wind!” I shouted. “I told you I wasn’t mad!”

I like how the story shows how long, hard work, reading, experimenting and learning is what allowed William to success (page 194-5)

For the next month, about thirty people showed up each day to stare at the light. “How did you manage such a thing?” They asked. “Hard work and lots of research,” I’d say, trying not to sound too smug…
[to William’s father] “What an intelligent boy. Where did he get such ideas?”
“He’s been reading lots of books. Maybe from there?”
“They teach this in school?”
“He was forced to drop. He did this on his own.”
The diagram demonstrated twenty-four volts being transformed to two hundred forty. I knew voltage increased with each turn of wire. The diagram showed the primary coil to have two hundred turns, while the secondary had two thousand. A bunch of mathematical equations were below the diagram – I assumed they explained how I could make my own conversions – but instead I just wrapped like mad and hoped it would work. (page 200)
Soon I was attacking every idea with its own experiment. Over the next year, there was hardly a moment when I wasn’t planning or devising some new scheme. And though the windmill and radio transmitter had both been successes, I couldn’t say the same for a few other experiments. (page 215)

William is now attending the African Leadership Academy in South Africa, with an amazing group of classmates. See how you can support the Moving Windmills Projects.

Related: Teen’s DIY Energy Hacking Gives African Village New HopeMake the World BetterWilliam Kamkwamba on the Daily ShowWhat Kids can Learnappropriate technology

Microcosm by Carl Zimmer

cover of Microcosm by Carl Zimmer

Microcosm: E. Coli and the New Science of Life by Carl Zimmer is an excellent book. It is full of fascinating information and as usual Carl Zimmer’s writing is engaging and makes complex topics clear.

E-coli keep the level of oxygen low in the gut making the resident microbes comfortable. At any time a person will have as many as 30 strains of E. coli in their gut and it is very rare for someone ever to be free of E. coli. [page 53]

In 1943, Luria and Delbruck published the results that won them the 1969 Nobel Prize in Physiology or Medicine in which they showed that bacteria and viruses pass down their traits using genes (though it took quite some time for the scientific community at large to accept this). [page 70]

during a crisis E coli’s mutation rates could soar a hundred – or even a thousandfold… Normally, natural selection favors low mutation rates, since most mutations are harmful. But in times of stress extra mutations may raise the odds that organisms will hit on a way out of their crisis… [alternatively, perhaps] In times of stress, E coli. may not be able to afford the luxury of accurate DNA repair. Instead, it turns to the cheaper lo-fi polymerases. While they may do a sloppier job, E coli. comes out ahead [page 106]
Hybridization is not the only way foreign DNA got into our cells. Some 3 billion years ago our single-celled ancestors engulfed oxygen-breathing bacteria, which became the mitochondria on which we depend. And, like E. coli, our genomes have taken in virus upon virus. Scientists have identified more than 98,000 viruses in the human genome, along with our mutant vestiges of 150,00 others… If we were to strip out all our transgenic DNA, we would become extinct.

I highly recommend Microcosm, just as I highly recommend Parasite Rex, by Carl Zimmer.

Related: Bacteriophages: The Most Common Life-Like Form on EarthForeign Cells Outnumber Human Cells in Our BodiesAmazing Designs of LifeAmazing Science: RetrovirusesOne Species’ Genome Discovered Inside Another’s

Unless We Take Decisive Action, Climate Change Will Ravage Our Planet

Lake McDonald, Glacier National Park photo by John Hunterphoto by John Hunter at Glacier National Park.

Tomorrow 56 newspapers, in 45 countries, are taking the unprecedented step of publishing the same editorial. The editorial will appear in 20 languages, as the United Nations Climate Change Conference is set to begin in Copenhagen.

Unless we combine to take decisive action, climate change will ravage our planet, and with it our prosperity and security. The dangers have been becoming apparent for a generation. Now the facts have started to speak: 11 of the past 14 years have been the warmest on record, the Arctic ice-cap is melting and last year’s inflamed oil and food prices provide a foretaste of future havoc. In scientific journals the question is no longer whether humans are to blame, but how little time we have got left to limit the damage. Yet so far the world’s response has been feeble and half-hearted.

Climate change has been caused over centuries, has consequences that will endure for all time and our prospects of taming it will be determined in the next 14 days. We call on the representatives of the 192 countries gathered in Copenhagen not to hesitate, not to fall into dispute, not to blame each other but to seize opportunity from the greatest modern failure of politics. This should not be a fight between the rich world and the poor world, or between east and west. Climate change affects everyone, and must be solved by everyone.

The science is complex but the facts are clear. The world needs to take steps to limit temperature rises to 2C, an aim that will require global emissions to peak and begin falling within the next 5-10 years.

Few believe that Copenhagen can any longer produce a fully polished treaty; real progress towards one could only begin with the arrival of President Obama in the White House and the reversal of years of US obstructionism. Even now the world finds itself at the mercy of American domestic politics, for the president cannot fully commit to the action required until the US Congress has done so.

the rich world is responsible for most of the accumulated carbon in the atmosphere – three-quarters of all carbon dioxide emitted since 1850. It must now take a lead, and every developed country must commit to deep cuts which will reduce their emissions within a decade to very substantially less than their 1990 level.

The transformation will be costly, but many times less than the bill for bailing out global finance — and far less costly than the consequences of doing nothing.

Many of us, particularly in the developed world, will have to change our lifestyles. The era of flights that cost less than the taxi ride to the airport is drawing to a close. We will have to shop, eat and travel more intelligently. We will have to pay more for our energy, and use less of it.

Kicking our carbon habit within a few short decades will require a feat of engineering and innovation to match anything in our history. But whereas putting a man on the moon or splitting the atom were born of conflict and competition, the coming carbon race must be driven by a collaborative effort to achieve collective salvation.

The politicians in Copenhagen have the power to shape history’s judgment on this generation: one that saw a challenge and rose to it, or one so stupid that we saw calamity coming but did nothing to avert it. We implore them to make the right choice.

Most of the newspapers have taken the unusual step of featuring the editorial on their front page. Even with the overwhelming evidence and tremendous consequences I don’t expect politicians to make the right decisions. We know full well what the choices are. We just decide to avoid the unpleasant choices. To bad so many that don’t get to choose are going to suffer. The politicians will be weak. They will play to those that pay them money. They will delay taking important steps now. We have chosen to elect non-leaders for quite some time. We can’t really expect them to act with courage, vision, wisdom and leadership given who we elect. The politicians are responsible for their failing but we are more responsible for electing them. Some politicians, even now, do possess fine qualities but not nearly enough. Maybe I will be proven wrong, but I doubt it.

Related: What’s Up With the Weather?Arctic System on Trajectory to New, Seasonally Ice-Free StateScientists Denounce Global Warming Report EditsDeforestation and Global WarmingMIT’s Energy ‘Manhattan Project’Global Installed Wind Power Now Over 1.5% of Global Electricity DemandBigger Impact: 15 to 18 mpg or 50 to 100 mpg?Solar Thermal in Desert, to Beat Coal by 202076 Nobel Laureates in Science Endorse Obama

Feynman “is a second Dirac, only this time human”

Oppenheimer recommendation of Feynman, page 1

Great quotes from Oppenheimer’s recommendation of Richard Feynman

“He is by all odds the most brilliant young physicist here, and everyone knows this. He is a man of thoroughly engaging character and personality, extremely clear, extremely normal in all respects, and an excellent teacher with a warm feeling for physics in all its aspects. He has the best possible relations both with the theoretical people of whom he is one, and with the experimental people with whom he works in very close harmony.”

Bethe has said that he would rather lose any two other men than Feynman from this present job, and Wigner said, ‘He is a second Dirac, only this time human.”

Oppenheimer recommendation of Feynman, page 2

Images of letter from Oppenheimer to the University of California – Berkeley Recommending Richard Feynman for a position, November 4, 1943 (from Big Science at Berkeley).

via: He is a second Dirac, only this time human.

Related: Vega Science Lectures: Feynman and MoreThe Feynman Lectures on Physics by Richard P. Feynman and Robert B. Leighton and Matthew Sands – posts on physics

Re-engineering the Food System for Better Health

Good food nation

According to the Centers for Disease Control, between 1980 and 2006 the percentage of obese teenagers in the United States grew from 5 to 18, while the percentage of pre-teens suffering from obesity increased from 7 to 17.

Obesity is widespread due to our national-scale system of food production and distribution, which surrounds children – especially lower-income children – with high-calorie products…
90 percent of American food is processed – according to the United States Department of Agriculture – meaning it has been mixed with ingredients, often acting as preservatives, that can make food fattening.

Now, in another report finished this October after meetings with food-industry leaders, the MIT and Columbia researchers propose a solution: America should increase its regional food consumption.

Only 1 to 2 percent of all food consumed in the United States today is locally produced. But the MIT and Columbia team, which includes urban planners and architects, believes widespread adoption of some modest projects could change that, by increasing regional food production and distribution.

To help production, the group advocates widespread adoption of small-scale innovations such as “lawn to farm” conversions in urban and suburban areas, and the “10 x 10 project,” an effort to develop vegetable plots in schools and community centers. Lawns require more equipment, labor and fuel than industrial farming nationwide, yet produce no goods. But many vegetables, including lettuce, cucumbers and peppers, can be grown efficiently in small plots.

As Albright sees it, the effort to produce healthier foods “fits right in with the health-care reform effort right now because chronic diseases are so costly for the nation.” America currently spends $14 billion annually treating childhood obesity, and $147 billion treating all forms of obesity.

Good stuff. We need to improve health in the USA. The current system is unhealthy and needs to be improved. The public good from improving the health of society is huge (both in terms of individual happiness and economic benefits).

Related: Rethinking the Food Production SystemStudy Finds Obesity as Teen as Deadly as SmokingEat food. Not too much. Mostly plants.Active Amish Avoid ObesityObesity Epidemic ExplainedAnother Strike Against Cola

William Kamkwamba on the Daily Show

Pointy haired bosses removed the video. Argh!

William Kamkwamba on the Daily show. I first posted about William’s great work in 2007 – Home Engineering: Windmill for Electricity. What a great example of what can be done by sharing scientific and engineering ideas with those who will make the effort to create workable solutions.

William has written a book on his life: The Boy Who Harnessed the Wind.

Related: Inspirational EngineerMake the World Betterposts on engineersposts on Africa

The Value of Displaying Data Well


Anscombe’s quartet: all four sets are identical when examined statistically, but vary considerably when graphed. Image via Wikipedia.

___________________
Anscombe’s quartet comprises four datasets that have identical simple statistical properties, yet are revealed to be very different when inspected graphically. Each dataset consists of eleven (x,y) points. They were constructed in 1973 by the statistician F.J. Anscombe to demonstrate the importance of graphing data before analyzing it, and of the effect of outliers on the statistical properties of a dataset.

Of course we also have to be careful of drawing incorrect conclusions from visual displays.

For all four datasets:

Property Value
Mean of each x variable 9.0
Variance of each x variable 10.0
Mean of each y variable 7.5
Variance of each y variable 3.75
Correlation between each x and y variable 0.816
Linear regression line y = 3 + 0.5x

Edward Tufte uses the quartet to emphasize the importance of looking at one’s data before analyzing it in the first page of the first chapter of his book, The Visual Display of Quantitative Information.

Related: Edward Tufte’s: Beautiful EvidenceSimpson’s ParadoxCorrelation is Not CausationSeeing Patterns Where None ExistsGreat ChartsPlaying Dice and Children’s NumeracyTheory of Knowledge

Controlled Experiments for Software Solutions

by Justin Hunter

Jeff Fry linked to a great webcast in Controlled Experiments To Test For Bugs In Our Mental Models.

I firmly believe that applied statistics-based experiments are under-appreciated by businesses (and, for that matter, business schools). Few people who understand them are as articulate and concise as Kohavi. Admittedly, I could be accused of being biased as: (a) I am the son of a prominent applied statistician and (b) I am the founder of a software testing tools company that uses applied statistics-based methods and algorithms to make our tool work.

Summary of the webcast, on Practical Guide to Controlled Experiments on the Web: Listen to Your Customers not to the HiPPO – a presentation by Ron Kohavi with Microsoft Research.

1:00 Amazon: in 2000, Greg Linden wanted to add recommendations in shopping cards during the check out process. The “HiPPO” (meaning the Highest Paid Person’s Opinion) was against it on the grounds that it would be a bad idea; recommendations would confuse and/or distract people. Amazon, a company with a good culture of experimentation, decided to run a small experiment anyway, “just to get the data” – It was wildly successful and is in widespread use today at Amazon and other firms.

3:00 Dr. Footcare example: Including a coupon code above the total price to be paid had a dramatic impact on abandonment rates.

4:00 “Was this answer useful?” Dramatic differences occur when Y/N is replaced with 5 Stars and whether an empty text box is initially shown with either (or whether it is triggered only after a user clicks to give their initial response)

6:00 Sewing machines: experimenting with a sales promotion strategy led to extremely counter-intuitive pricing choice

7:00 “We are really, really bad at understanding what is going to work with customers…”
Continue reading

Another Survey Shows Engineering Degree Results in the Highest Pay

The PayScale salary survey looked at both starting and mid career salary. Engineering topped both measures. Of the top 10 mid career salaries, 7 were engineering degrees – including the top 4. The survey is based upon data for full-time employees in the United States who possess a Bachelor’s degree and no higher degrees and have majored in the subjects listed above.

The top 11 paying degrees are:

Highest Paid Undergrad College Degrees
Degree Starting Median Salary Mid-Career Median Salary
Aerospace Engineering $59,600 $109,000
Chemical Engineering $65,700 $107,000
Computer Engineering $61,700 $105,000
Electrical Engineering $60,200 $102,000
Economics $50,200 $101,000
Physics $51,100 $98,800
Mechanical Engineering $58,900 $98,300
Computer Science $56,400 $97,400
Industrial Engineering $57,100 $95,000
Environmental Engineering $53,400 $94,500
Statistics $48,600 $94,500

Related: Engineering Graduates Paid Well Again in 2008High Pay for Engineering Graduates in 2007Engineering Graduates Get Top Salary Offers in 2006posts on science and engineering careersposts on engineering education

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