Author Archives: curiouscat

Correlation is Not Causation: “Fat is Catching” Theory Exposed

Their study was reported to have shown that you can “catch” obesity from having fat friends and that obesity is so contagious, it can be spread long-distance by email and instant messaging. Even healthcare professionals, who didn’t understand the etiology of true obesity or how statistics can be misused, failed to detect the implausibility of “second-hand obesity.” In fact, some doctors became so enamored with the new “science of networking” they believed it should be a new medical specialty: network medicine.
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Jason M. Fletcher, Ph.D., assistant professor at the Yale School of Public Health in New Haven, Connecticut, along with Boston economist, Ethan Cohen-Cole, Ph.D., designed an ingenious study. They selected conditions that no one would seriously believe were spread by social networking and online friendships: height, headaches and acne. They then applied the same standard statistical methods used in Christakis and Fowler’s social networking research to “find” that acne, height and headaches have the same “social network effect.”
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As they explained, patterns of association among people can lead to correlations in health conditions between friends that are not caused by direct social network effects at all.
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There is a need for caution when attributing causality to correlations in health outcomes between friends using non-experimental data. Confounding is only one of many empirical challenges to estimating social network effects.

Excellent reminder of the risks of analyzing data for correlations. We continue to, far to often, fail to interpret data properly. Both authors of the study, received PhD’s from the University of Wisconsin-Madison which strengthens my belief that it is teaching students well (just kidding).

Also another example of the scientific inquiry process where scientists challenge the conclusions drawn by other scientists. It is a wonderful system, even if confusing and not the clean idea so many have of how science works.

Rumors of Software Engineering’s Death are Greatly Exaggerated

Rumors of Software Engineering’s Death are Greatly Exaggerated by Steve McConnell

Indeed, one of the hallmarks of engineering as opposed to science is that engineers will work with materials whose properties are not entirely understood, and they’ll factor in safety margins until the science comes along later and allows more precision in the engineer’s use of those materials.
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Software engineering already has been defined as engineering, we have an international reference standard for that definition, the field’s two largest professional bodies have jointly adopted a professional code of conduct for software engineers, we have accreditation standards for university programs in software engineering, we have university numerous programs that have already been accredited, and several countries are licensing professional engineers in software.

How Marbles Are Made

More posts on how things work: Why do We Sleep? – Why is it Colder at Higher Elevations? – What Are Flowers For?

A Microscopic Layer of Diamonds Beneath the Surface of North America

Diamonds show comet struck North America, scientists say

A discovery of microscopic diamonds a few feet beneath the surface of North America reveals that a comet caused a cataclysm of fire, flood and devastation nearly 13,000 years ago that extinguished mammoths and mastodons and dealt a blow to early civilization, scientists said Friday.

The nanodiamonds, so small that they are barely visible in an electron microscope, are thought to be remnants of that comet, which would have hit about 65 million years after the much larger collision that wiped out the dinosaurs.
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Battered by fire and ice, as many as 35 species of mammals, including American camels, the short-faced bear, the giant beaver, the dire wolf and the American lion, either immediately vanished or were so depleted in number that humans hunted them to extinction.

The humans, a Paleo-Indian grouping known as the Clovis culture for the distinctive spear points they employed, suffered a major population drop, disappearing in many areas for hundreds of years.
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gems can only be created under the extreme temperatures and pressures of a massive explosion, such as a comet striking the Earth’s surface.

“There’s no other way we can interpret the presence of these diamonds other than an extraterrestrial impact,” said James Kennett, a paleooceanographer.

Such an impact would be the most likely source of nanodiamonds, critics agreed. But many argued that the one-page paper in Science did not provide enough evidence to support the authors’ claim.

“Nanodiamonds could be a good indicator of an impact event . . . but after reading the paper, I wasn’t convinced they found diamonds,” said physicist Tyrone Daulton of Washington University in St. Louis. “Maybe they found diamonds and maybe they didn’t.”

Post 2009

My first post in 2009 is the 2009th post for the blog. Here are some highlights from 2008:

Swarm of Yellowstone Quakes Baffles Scientists

photo of Yellowstone's Old Faithful by John Hunter

Photo of Old Faithful geyser in Yellowstone National Park by John Hunter

Swarm of Yellowstone Quakes Baffles Scientists

Swarms of small earthquakes happen frequently in Yellowstone, but it’s very unusual for so many earthquakes to happen over several days, said Robert Smith, a professor of geophysics at the University of Utah. “They’re certainly not normal,” Smith said. “We haven’t had earthquakes in this energy or extent in many years.”
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“There doesn’t seem to be anything to be alarmed about,” Vallie said. Smith said it’s difficult to say what might be causing the tremors. He pointed out that Yellowstone is the caldera of a volcano that last erupted 70,000 years ago.
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Yellowstone has had significant earthquakes as well as minor ones in recent decades. In 1959, a magnitude 7.5 quake near Hebgen Lake just west of the park triggered a landslide that killed 28 people.

So far the most powerful quake over the last few days has been one at 3.8 on the Richter scale. An earthquake of 4.0-4.9 “Noticeable shaking of indoor items, rattling noises. Significant damage unlikely.” The Richter scale is a logarithmic scale, meaning a measure of 4.0 is 10 times as powerful as 3.0 quake, and 5.0 is 100 times more powerful than a 3.o quake.

Learning About the Moon

Planetary scientist Jennifer Heldmann discusses the Moon. From Fora.tv which has a wide selection of great webcasts.

Open Source Abandoned by OLPC

Not Free at Any Price by Richard M. Stallman

When the OLPC appeared, it fell one step short of full freedom: the highly publicized wireless mesh network device, which allows OLPCs to connect to the Internet through nearby OLPCs, required a non-free program. This piece of non-free code prevented me from fully endorsing the OLPC. But that would not stop me from using one: I would just have to delete the non-free code and do without the internal wireless device.

The OLPC had practical inconveniences, too: no internal hard disk, a small screen, and a tiny keyboard. In December 2007 I test-drove the OLPC with an external keyboard, and concluded I could use it with an external disk despite the small screen. I decided to switch.
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If you want to support a venture to distribute low-priced laptops to children, wait a few months, then choose one that donates MIPS-based machines that run entirely free software. That way you can be sure to give the gift of freedom.

He is more anti-microsoft than I am but I agree with this contention that what we should support is a open source solution to provide laptops to children around the world. It is a shame, I really liked the potential for OLPC. I still wish them success I just am not interesting in directly supporting that effort but instead would like an alternative open source solution.

The Sylvania Netbook is available from Amazon now with the Ubuntu operating system (linux version). I use Ubuntu and it is excellent.

The Year in Bad Science

The Year in Bad Science Ben Goldacre reviews some of the science lowlights of the year.

In a world where rigorous evidence from scientific research languishes unpublicised, the media continued to churn out bogus wacky science stories. Britain’s happiest places were mapped by “scientists”, although the differences were just chance findings; there were innumerable “surveys” from unrepresentative populations; and the right wing press claimed that “Lord Nelson and Captain Cook’s ship logs question climate change theories,” although they did nothing of the sort, as the researchers themselves helpfully explained. We saw how the BBC misrepresented the statistics on parents’ choices about keeping a Down’s Syndrome pregnancy, producing their a publicity avalanche on the back of an incorrect story, and learnt along the way about confounding variables, baseline changes, and more.

In the world of evidence based social policy we saw how the government quietly dropped death as an outcome indicator for their drugs policy, the fascinating inconsistencies in food additive judgment calls, and more. We also watched with delight as right-wing think tank Reform produced a report on the crisis in maths in which they got their maths wrong.

Rethinking the Food Production System

photo by John Hunter of wine-berries from his Garden.

Food needs ‘fundamental rethink’

The new approach needed to address key fundamentals like biodiversity, energy, water and urbanisation, he added.
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Water scarcity: “One of the key things that I have been pushing is to get the UK government to start auditing food by water,” Professor Lang said, adding that 50% of the UK’s vegetables are imported, many from water-stressed nations.
Biodiversity: “Biodiversity must not just be protected, it must be replaced and enhanced; but that is going to require a very different way growing food and using the land.”
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“In Europe, 30% of the food grown did not appear on the shelves of the retailers because it was a funny shape or odd colour.
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“The way that seeds are selected is about immunity to any known disease; they have also got to grow big and fast, and have a fantastic shelf life. “Never mind taste, texture or nutrition, it is all about how it looks.

I agree. The food system is broken. We have moved to mono-culture food production. We have changed our diets to eat food like concoctions. We need to return to healthier and sustainable food production.