September 24th, 2008 — Advanced Problems in Science
For my new course, Advanced Problems in Science, my students will occasionally be writing blog entries about a variety of subjects. I intend to write about the same subjects when they do. Our first blog entry was about “black boxes” - you can add input and see output, but you don’t know what’s going on inside/how it does what it does. In science, the atom is a black box. So is the universe. In class, we each chose a black box in our lives to write about (such as LCD televisions, Segways, ethanol engines, etc.), trying to find out how it worked. I let the class pick my topic and they chose the Wii Remote Control.
The Nintendo Wii is a game console which has been around a few years now. What makes it stand out from other game consoles is the remote used to interact with the games. Rather than a wired remote with simple push buttons, or even a wireless remote with simple push buttons, the Wii remote (often called Wiimote) responds to the motion of the user (as well as having simple push buttons). So how does this revolutionary game controller work? I’ve decided to check out a few sources online (see below the article) to see if I can figure it out.
The Wii Remote Control (Wiimote)
It appears there are three key parts to a Wiimote to allow it to work as advertised. There is an accelerometer, an infrared sensor, and a Bluetooth radio.
The accelerometer in the Wiimote can sense a change in speed or direction (thus sense acceleration) in all three dimensions (length, width, height or x, y, z). The accelerometer cannot detect position, only change in position (or more specifically, change in velocity). The infrared sensor combined with the accelerometer allow the Wiimote to determine position as well as type of motion.
The infrared sensor in the Wiimote detects infrared (IR) signals from the Sensor Bar which ships with the Wii and is set on or in front of the television used for gaming. The Sensor Bar has ten light-emitting diodes (LEDs) which give off IR light, five on one side, five on the other. Using the signals the Wiimote’s IR sensor picks up, it can figure out its position relative to the Sensor Bar using triangulation. Moving the Wiimote too close or too far from the Sensor Bar can affect the accuracy of the Wiimote.
The information from the accelerometer and the IR sensor need to be sent to the Wii itself for the controller to be able to actually control the game. The Bluetooth radio in the Wiimote sends the signal through the air to the Wii, which has a Bluetooth receiver. Bluetooth is a standard wireless protocol used in a number of devices such as cell phones, wireless mice, and GPS recivers.
In addition to gathering information and sending it to the Wii, the Wiimote can receive information to give some feedback to the person using it, such as audio and rumble feedback. This article won’t go into detail about how those features work. (I wonder if there’s a small gyroscope in the Wiimote which allows the rumble feedback to work.)
References:
August 6th, 2008 — Biology, Masters Program
In the animal kingdom, males often compete with each other for the chance to mate with females. Antlers on deer and horns on beetles, for example, help those males compete against others. However, when females mate with multiple males, fighting isn’t the only way to ensure the male will produce offspring – having a greater chance at fertilization (thus, having more sperm) also increases the chances of passing on genes. Leigh W. Simmons and Douglas J. Emlen (from University of Western Australia and University of Montana respectively) have been studying horned beetles to see how the development of weaponry and testes relate. For the most part, they discovered that the two are inversely related.
Other scientific studies have looked at how animals trade off between important organ development. For example, it takes a lot of energy to run a brain and it takes a lot of energy to produce large testes (the sperm producer in animals) – so in some bats, a larger brain means smaller testes. In fruit flies, larger testes means a longer time to develop. The scientists in this study decided to examine horn development (weapons used to claim a mate) and testes size. They had noticed that in horned beetle species where some males have large horns and others have small or missing horns, the hornless males would often sneak by horned beetles and try to mate with their females. In order to be successful, these hornless beetles must produce more sperm than their horned counterparts.
The team first experimented with modifying horned beetle larva. They cauterized the area which would have developed horns. Then they let the larva develop into adults. The adults grew larger than the beetles which were allowed to develop horns. The cauterized males also had larger testes than the horned males. The experiment was performed on beetles which produced horns in the thorax rather than the head. Apparently the organisms will trade off between organs close to each other. In order to have larger head horns, a beetle would wind up with smaller eyes or another organ on or near the head.
After the experiment, the scientists examined the “family tree” of the horned beetle genus (Onthophagus). They wanted to see if the horn size/testes size trade off followed throughout the beetle family. They found out it wasn’t as straightforward as “bigger weapons, smaller testes,” but the overall trend was there. When they compared horn size to body size and compared testes size to body size, they got a range of sizes. In species with a huge range of horn sizes, there was a small range of testes sizes. Likewise, in species with a huge range of testes sizes, there was a small horn size range.
During the development of horned beetles in their larval state, they have a limited pool of resources. So trade-offs between organ development happen. What Simmons and Emlan found was a trade off between horn development and testes size. They can either have bigger weapons for fighting for a mate, or they can have more sperm to fertilize eggs. Both traits help to carry on their genes, but for the most part, they can only focus on one of the two. So if you were a male horned beetle, which would you choose (if you could actually choose)? Bigger weapons or bigger testes?
Original Science Article: L. W. Simmons and D. J. Emlen, Evolutionary trade-off between weapons and testes. Proceedings of the National Academy of Sciences, 2006; 103: 16346-16351. http://www.pnas.org
July 30th, 2008 — Masters Program, Social Engineering
This week’s article and next week’s are both examples of USA Today-style science articles. Smaller word count, lower reading level. I actually found these easier to write than the New York Times-style articles. Once again, I snuck a graph in. Heh.
“But mo-ommm! Why do I have to reduce my greenhouse gas emissions? The other kids don’t have to!”
Although you may not heard it said so petulantly, a lot of people wonder why they should be the ones to reduce their carbon footprint when there are millions (even billions) of other people out there who aren’t. When you have over 6 billion people sharing the same planet, not everyone will wind up being good stewards of the planet. But it is a hopeless cause? Or can people be selfless in their treatment of the planet? One study in Germany suggests that yes, people can be altruistic in their earth stewardship. Although it helps if they can get a bit of recognition for doing so.
Manfred Milinkski and his team of researchers from the Max Planck Institute worked with 156 undergraduate students from Hamburg University in a computerized experiment “to see whether they would contribute their own money to sustain the global climate in a public goods game.” Basically, the participants started out with 12 euros (€12) each. They could either donate €0, €1 or €2 towards advertising to inform the population of the latest meteorological findings regarding the Earth’s climate. The next round of the “public goods game” would then have them either donating or receiving money from one of the other participants based upon their reputation as a donor (the “indirect reciprocity round”). The following round would be like the first, only this time everyone participating was anonymous. Another indirect reciprocity round followed. The game continued for twenty rounds. They performed the test using people who had little information about the global climate. Then they used people who were kept up to date on the current research.
The researchers were not surprised to find out that the students who were more informed on the issues of global warming were more likely to donate money (54.6% compared to 39.7% for anonymous participants) to the cause of advertising the climate research. What did surprise them was that the non-anonymous donations were also greater than the anonymous ones. (94.4% for informed non-anonymous donors compared to 54.6%.) When other people could see that they were donating to the cause, participants were more likely to donate than not. Indeed, when people didn’t donate to the cause, they were more likely to be punished (not given anything in the indirect reciprocity round) than those who did.
Figure 1: The solid circles are public donations while the hollow circles are anonymous. The red data shows the well-informed participants while the blue data indicates the little-informed participants. The well-informed participants always donated more than the less-informed ones. Likewise, the public donations were always higher than the anonymous ones.
If someone is donating in order to gain a positive reputation, is that really altruism? The researchers don’t think so, but they still think the outcome is desirable. Regardless of why people increase their earth stewardship, the fact that they do it is the important thing. “The benefit of investing to the climate pool, a stabilized climate, potentially lies in the distant future, so the investment might be viewed as being equivalent to a donation to charity.” A key difference between donating to a charity and investing in climate stabilization is that the donor is more likely to reap the benefits of the climate improvements than of the charity.
“Designing strategies to improve the social reputation of people investing in climate protection thus ought to figure prominently in climate policy makers’ priorities,” concludes the researchers in their study. Informing the population about the current climate concerns will help increase earth stewardship, but finding a way to “reward” good stewards will help even more.
“See, little Johnny next door is reducing his carbon footprint, Sally! I’m sure you can do so as well!”
Original Science Article: M. Milinski, D. Semmann, H.-J. Krambeck and J. Marotzke, Stabilizing the Earth’s climate is not a losing game: supporting evidence from public goods experiments. Proceedings of the National Academy of Sciences 2006; 103: 3994-3998. http://www.pnas.org
July 23rd, 2008 — Biology, Masters Program, Social Engineering
In an age when uncorroborated conspiracy theories run rampant, it is surprising to find one that has evidence to support it. According to the study “Tobacco industry sociological programs to influence public beliefs about smoking” by Anne Landman, Daniel K. Cortese and Stanton Glantz, several tobacco companies in the 80s and 90s were working together to combat the negative press that cigarette smoking was receiving. Landman et al examined previously secret documents from companies such as Philip Morris and agencies such as the Tobacco Institute looking for key terms like “social” and “social costs” as well as “budget” and “report.” They found a wealth of evidence that the tobacco industry was using several techniques to combat the anti-smoking campaign. Landman also warns that the tobacco industry may still be using their well-honed propaganda techniques to this day.
In the late 1970s, the first reports about second-hand smoke and the social costs of smoking were published. This helped reduce the popularity of smoking. Up until that point, non-smokers were not very involved in anti-smoking campaigns. The tobacco industry became worried and looked for a way to fight the growing unpopularity of smoking. They had three key things in their favor: knowledge is a social construction, strongly interconnected with power; academics usually are highly regarded and that gives their opinions power; and academics require funding and that makes them susceptible to corporate influences. To combat the declining social acceptability of smoking, the tobacco industry gathered their own biomedical, economic, and social scientists to report on second hand smoke and other social smoking concerns.
The R. J. Reynolds Tobacco Company (RJR) started a project in 1977 to investigate three key things: what key issues motivate public opinion on the social acceptability of smoking, what are some countermeasures that can sway opinion in their favor, and how feasible would it be to create a long-term program to improve the public opinion on smoking. To avoid being targeted by other tobacco companies in their proposed long term project, they addressed the Tobacco Institute (the tobacco industry’s U.S. lobbying agency) to make it an industry-wide initiative. RJR and several international tobacco companies met and put together a Social Costs/Social Values (SC/SV) project and formed the International Committee on Smoking Issues (ICOSI). Landman wrote in the study, “ICOSI members adopted the plan in 1979 to secretly recruit and fund a group of prominent academic sociologists, philosophers, economists, anthropologists and political scientists to develop arguments promoting the benefits of smoking, refute arguments about the social costs of smoking, and emphasize the negative effects the companies believed smoking bans had on society.”
A 1980 progress report on the program stated that academics would be commissioned to research many cultures in order to show the social importance of smoking. They also wanted the academics to discover ways to reverse the current research findings indicating that smoking was a health hazard and to support the concept that smoking is “normal.” A common technique used was to have a third-party (non-tobacco industry) host a conference, but have them invite the speakers which the industry requested. “Another SC/SV project activity was to have the academics ‘generate [pro-industry] papers, which can then be used as references in direct confrontation with the [social costs] issue.’” The goal would then be to have these papers published in professional journals so that other studies could cite them. Pro-industry consultants using these papers to back up their positions did have to avoid medical arguments, which the industry couldn’t defend against. Rather than focus on an individual’s “benefits” from smoking, the consultants discussed how groups are affected positively by smoking.
Since 1969, the tobacco industry had a “special accounts” budgetary item to secretly pay medical researchers and in 1979, they included payment to the academics writing about the positive social effects of smoking. In 1985, the book Smoking and Society: Towards a More Balanced Perspective was published. Edited by economist Robert Tollison (hired by the tobacco industry to be a third-party editor), the book was a collection of essays written to counter the anti-smoking campaign. In the introduction of the book, Tollison wrote, “There is a serious and useful scholarly case to be made that the conventional wisdom about smoking behavior is either wrong, unproven, built upon faulty analysis or pushed well beyond the point of common sense.” Of the 14 authors in the book, 11 had undisclosed ties to the tobacco industry.
Promotion of the book was done by the publishing company – the tobacco industry knew they needed to be out of the picture during the promotion of the book. It was recommended as an aid for reporters and policy makers to indicate the “other side” to the smoking issue. Smoking and Society was also promoted to university professors teaching in the social sciences. (Perhaps the original “teach the controversy”?)
Tollison wrote a follow-up book entitled Smoking and the State: Social Costs, Rent Seeking and Public Policy which was more heavily promoted by the tobacco industry. The book focused on economic issues with the indoor clean air act and other anti-smoking endeavors. The Tobacco Institute actually paid 17 of their consulting economists to write favorable reviews of the book. According to the Institute president, the book received favorable news stories and book reviews.
The third Tollison book, Clearing the Air: Perspectives on Environmental Tobacco Smoke, was the first to be openly endorsed by the tobacco industry. It was translated in to several languages for publishing abroad. It was used as ammunition for the arguments over second hand smoke. Thanks to the three books by Tollison, he was able to argue as a pro-smoking “expert” in several anti-smoking initiative trials by the government (including a bill that proposed banning smoking in government buildings).
In 1988, a report on nicotine’s addictive quality spurred two tobacco industry agencies (Rothmans Tobacco in the UK and Philip Morris in the US) to create ARISE (Associates for Research in Substances of Enjoyment). The function of ARISE was to separate the nicotine from other drugs in the public’s mind. They claimed to be an apolitical organization and attacked the anti-smoking side for being puritanical and the scientists reporting on nicotine’s addictive nature for being politically corrupt.
More tobacco industry companies joined in supporting ARISE, although they publicly distanced themselves from the organization. “Through ARISE, the sponsoring tobacco companies generated news articles around the world that ridiculed and derided public health goals around smoking and reassured people about the relative safety and benefits of smoking,” Landman’s study reports. The organization generated hundreds of press articles and media reports in several countries. They held conferences which attacked the US Surgeon General’s reports that nicotine was as addictive as cocaine or heroin. Indeed, they often compared smoking to activities as innocuous as eating or drinking.
ARISE disbanded in 1999, though the researchers for this study have been unable to ascertain why. “We were unable determine why the group was disbanded after it had served the industry so well, or whether it has been reconstituted in another form,” Landman writes. If an organization like ARISE is still around, there could still be effective forms of pro-smoking propaganda in our media today.
How can people be certain that what they are reading hasn’t been tainted with tobacco industry money? Landman and her associates have some suggestions on identifying such information. “The public should be skeptical of commentaries that use arguments exposed in this report as having been commissioned and highly promoted by the industry. Common pro-tobacco arguments that divert the focus away from health, like civil rights, Puritanism, economic doom, class warfare, prohibition, excessive government intrusion, tyranny and creeping totalitarianism can indicate the presence of industry influence,” Landman’s report concludes. She recommends that full disclosure be mandatory by any proponent of findings of a pro-smoking study. The tobacco industry has been sneaky before, it could be doing so still today.
It is interesting to note that when Landman and her team were looking for the academics mentioned in the various documents of their research, only five were still active in the field, and none of them wished to comment in the report. Perhaps another study could try and discover what happened to all of the other academics involved in the tobacco industry’s long term projects. Did they receive enough money to retire early? Did they leave their field to make a clean start in another? Did they decide what they were doing was wrong? It certainly would make for an interesting report, if the academics would participate in such a project. Perhaps with sufficient funds, the academics would be willing to – after all, they had been bought before.
Original Science Article: A. Landman, D. K. Cortese and S. Glantz, Tobacco industry sociological programs to influence public beliefs about smoking. Social Sciences and medicine 66: 970-981, 2008.
July 16th, 2008 — Biology, Masters Program
This article and next week’s are my attempts at New York Times-style science reporting, which was undertaken for my Scientific Writing course. While writing these, I found a new respect for science writers - this isn’t easy! Although my professor thought I had too many graphs for a newspaper article, I’ve gone ahead and left them in because, let’s face it, I’m a graph geek.
Could global warming be responsible for the extinction of several species of frogs and toads? The report “Widespread amphibian extinctions from epidemic disease driven by global warming” by J. A. Pounds, et al, suggests it. After examining several variables suspected to affect amphibian species extinction, a pathogenic outbreak purportedly caused by warming trends was the most likely to affect the mass extinction of several tropical frog and toad species.
In the mountains of Costa Rica, there were once over a hundred species of Atelopus frogs (also known as harlequin frogs). Now 67% of those species are extinct. Pounds and his team have been studying the frog populations of the region for seventeen years and have observed that, with the warming of the region, the number of extinct species increases. According to the report, “analyzing the timing of losses in relation to changes in sea surface and air temperatures, we conclude with ‘very high confidence’ (>99%, following the Intergovernmental Panel on Climate Change, IPCC) that large-scale warming is a key factor in the disappearances.” What causes that extinction isn’t completely understood, but Pounds examined the chytrid fungus, Batrachochytrium dendrobatidis, and its relation to the Atelopus species in this study.
Batrachochytrium growing on a frog’s skin causes the disease chytridiomytosis, but usually only in cooler climates (in the highlands or during winter). In other times the fungus may merely act as a parasite or saprophyte (organism that lives off of other decomposing organisms). So why would warmer temperatures increase the chances of chytridiomytosis? The study attempts to explain the paradox. It’s possible that warmer or dryer conditions stress the amphibians to make them more susceptible to the disease. It’s also possible that there’s more to the chytrid fungus’s pathogenic nature than temperature.
In order to rule out effects caused by altitude, the study separated the species into two distinct altitude groups. When they did this, there was no difference in the extinction patterns between the two altitudes. Looking more deeply into the data, however, they found some interesting trends at particular altitudes. For example, extinct species at 200 meters increased sharply, as did species at 1000 meters. But at 2400 meters, there was a decrease. The pattern of greater extinctions at mid-range elevations fits with what other studies have shown. However, mid-range elevations usually house the greatest variation of species, which is usually more stable than regions with a small range of species. The study suggests that these increased extinction events at middle altitudes may also be affected by climate change, although more study is warranted.
Concerned that deforestation might be a confounding variable (that it also affects the extinctions), the study looked at the levels of deforestation in the region since the 1940s. Although 38% of the area had been cleared since the forties, only 11% had been cleared during the years of this study. Global temperatures, however, have increased steeply since the early seventies. In the Monteverde region of this study, the temperature has increased three times the global average increase (the region having a 0.18°C increase per decade). This level of increase is 18 times the projected increase that took place over the 8000 years between the last ice age and the modern day. With the models the study has produced, they found that the temperature increases affected humidity more than the deforestation has done.
Figure 1: This graph illustrates how the average air temperature (blue line) and average sea surface temperature (red line) have increased over the years.
Using the data they had gathered on frog populations, Pounds and his team created several models investigating the various variables and even possibilities arising from chance alone. The only models which fit the data indicated that temperature change was biggest factor. Even adding in El Niño effects to the temperature weren’t enough to explain the data. “Around 80% of the species that have disappeared were seen for the last time right after a relatively warm year.”
Figure 2: This graph shows how the average air temperature for the tropics (blue line) correlates with the number of extinct species (black line). (This data is for the lower elevation species.)
Although the average temperatures are increasing in the region of the study, the maximum temperature in a day is often decreasing. However, the lowest temperature of the day is now higher than it had been. The range of temperatures for a day are much shorter than they had been. It’s this shrinking of the daily range of temperatures which seems to favor the growth of the chytrid fungus. Among other things that this decrease in range with an increase in average temperature has done is increase the cloud cover of the region. This has brought the regions to the optimum temperatures for chytrid growth.
Figure 3: This graph illustrates how the range of temperatures in a day in the tropics is decreasing. The black lines indicate the average daily highs for the warmer months (upper black line) and cooler months (lower black line) while the green lines indicate the average daily lows for the warmer months (upper green line) and the cooler months (lower green line).
According to the study, the threat of global warming on species extinction isn’t a future possibility, it’s happening now. What their models and data have shown them is that several species of amphibians are already extinct due to the increases in temperature caused by global warming. What allows the increased temperatures to affect the species is epidemic diseases. In the case of the harlequin frogs in this study, it is a chytrid fungus responsible for the disease. As stated in the study, “the strength of association between warm years and disappearances is not related to altitude, latitude or range size.”
Regardless of your opinion on the strength of global warming and/or its causes, the data in this study is rather compelling. The relationship between air temperature and frog extinction is highly correlated. The explanation for the chytrid fungus growth is plausible. Is it actually a case of cause and effect? More study will need to be done to be sure about this, but the study by Pounds and his colleagues is a good start to know for certain.
Original Science Article: J. A. Pounds, M. R. Bustamante and L. A Coloma et al., Widespread amphibian extinctions from epidemic disease driven by global warming. http://www.nature.com
June 18th, 2008 — Masters Program, Misconceptions, Physics
B. Hanwerk, Extended daylight saving time not an energy saver? National Geographic News, March 7, 2008. http://news.nationalgeographic.com.
Actual reports: http://www.ucei.berkeley.edu and http://www2.bren.ucsb.edu
The expression “it’s the thought that counts” has a lot to answer for these days. Take Daylight Saving Time, for example. If you have Daylight Saving Time (DST) implemented, you’ll surely save energy because you’ll have more natural daylight to do your daily activities. But what about heating and air conditioning? Don’t they require energy use? Could they perhaps increase while illumination needs decrease during DST? In the article “Extended Daylight Saving Time Not an Energy Saver?” on the National Geographic website, two scientific studies on DST and energy consumption are summarized. Rather than just “thinking” that energy is saved, these scientists are looking at the evidence to see if it actually is or not.
National Geographic Article:
Shortly before we in the US started DST a month earlier than usual, Brian Handwerk for National Geographic News wrote the article mentioned in the paragraph above. He was questioning the thought that DST saves energy in the long run by citing two different studies which have been recently performed – one in Australia and one in Indiana.
Handwerk starts off by discussing the Australian study performed by Hendrik Wolff and Ryan Kellogg. Only three states in Australia have DST implemented, and in 2000, two of the three states did their DST earlier to accommodate the summer Olympics better. They compared Victoria (early adopter) to South Australia (regular DST) and their energy use. They found that, indeed, people used less energy for illumination during the early DST, but they also used more electrical energy in the morning than the regular DST. He quoted Wolff’s rejection of the government’s projected energy savings by extending DST.
The article continues by discussing the Indiana study performed by Matthew Kotchen and Laura Grant. Indiana didn’t have much consistency with DST observation until a new law in 2006 when all of Indiana became Central Standard Time with DST taking place in all counties. Handwerk says, “Their finding was clear: The switch to daylight saving time cost Indiana homeowners dearly on their electric bills.” He also quoted Kotchen’s caution about applying Indiana findings to the rest of the United States.
To finalize his article, Handwerk looks at the congressman who co-sponsored the bill to extend DST. Although they hadn’t seen any hard data supporting energy savings, they still supported the extension. The congressman’s press secretary said, “We’ve always said that the energy savings from this would be small compared to other changes you could make, but every little bit counts.” She then discussed other, non-energy savings benefits to DST, including reduced crime and increased traffic safety. However, she cited no studies showing such benefits, nor did Handwerk in his article.
Actual Scientific Articles:
The National Geographic News (NGN) piece was actually very short considering that it was covering two scientific studies and the congressman who co-sponsored the DST extension. The two studies were rather extensive and included some useful graphs to help illustrate the findings. I’ll start by examining the Australian study.
Wolff and Kellogg, as the NGN piece stated, compared the energy usage of two Australian states, Victoria and South Australia. New South Wales also started their DST a month early like Victoria, but since the Olympics were taking place in that state, they left it out of the study. They also removed the two weeks when the Olympics were actually in session to help remove confounding variables due to the event. From what they could tell, neither Victoria’s nor South Australia’s energy use were directly affected by the Olympics. With that in mind, they could then compare the two states using a statistical analysis called Difference in Differences (DID).
With the statistical study which they performed on the data they collected for both states, they found that energy use actually increased during the morning hours for Victoria (the early adopter). There was a distinct peak in energy use throughout the month extra. The energy use in the evening, however, was less. The graphs included in the study helped to illustrate the differences in energy use.
In addition to studying the energy use in the two states, Wolff and Kellogg also tested one of the models developed in 2001 which was showing a savings of energy during extended DST in California. When they used the model with the Australian data, it did not fit the data and so they had to reject the model. This shows that models developed for one area may not work for another (assuming the 2001 model even works for California).
The study in Indiana hits a bit closer to home for me (I live in Ohio and used to live close to the Ohio/Indiana border). With Indiana finally having a statewide agreement on time zone and DST in 2006, it was a good chance to study the effects of DST. Kotchen and Grant found that energy used for illumination was reduced, however heating and air conditioning use increased during the extended DST. Like the Australian study (which they cited in their report), the authors used the statistical process DID.
Kotchen and Grant also did several cost analyses of the area studied. On average, Indiana residents spent $3.19 more a year with the extended DST. Although that looks like a small amount of expense, multiply that by the number of Indiana households affected and the cost is in the millions. And that doesn’t include the pollution costs that increased energy usage causes. Like the NGN article, this study ends with several other reasons people might want extended DST which are not related to energy savings. The authors did warn, however, that studies have not been performed to confirm or deny the reasons.
Comparison:
I think my biggest disappointment in the NGN article was its brevity. Considering it was covering two scientific studies and a congressional apologist, it just wasn’t detailed enough. Although the article did cover the overall findings of the two studies (that energy most likely isn’t saved with an extension of DST), it didn’t push the ideas enough. With the final section concentrating on the people who are pushing the extension of DST and “other reasons” why DST might be useful to have around, I think it minimized the impact of the findings of the two studies.
If I had written the article, I think I would have included at least one of the graphs from one of the studies. The graphs (Fig. 3) showing the average half hourly electricity demand in South Australia and Victoria were excellent at showing how the early month affected energy use. They included data from the year before and year after, and the graph for 2000 in Victoria was distinctly different in the morning and evening hours.
Another thing I would have added to the article would have been the rejection of the 2001 model which has pushed the extension of DST in California and the US. The model didn’t work with Australian data – this could mean that Australia was an odd case that the model couldn’t predict well. But this could also mean that the model itself doesn’t work. This indicates to me that further study should be done before we use that model to determine national policy.
The quote from the congressman’s press secretary, “we’ve always said that the energy savings from this would be small compared to other changes you could make, but every little bit counts,” is actually a very irresponsible thing to say. If the data in Australia and Indiana were showing little to no savings in electricity, I could maybe get behind her statement. However, both studies have shown small (but statistically significant) increases. So what she’s saying is “well, it may increase energy use, but it’s the thought that counts.”
The NGN article ended with a few comments about other advantages to implementing extended DST. I don’t mind the idea that there may be other advantages. Indeed, I hope there are studies done to see if, indeed, there is reduced crime and increased traffic safety when DST is implemented. What I mind is people saying that we’re doing DST to save energy when it doesn’t appear to do that at all. Why not say we’re doing DST to increase leisure time for people during the warmer months? Don’t use bad or poorly researched science as a weapon to get policy implemented. Tell us the real reason why you want DST, Congressman. (More time on the yacht in the summer, perhaps?)
To summarize the article I’d've written instead of the actual NGN one, I would have concluded with the quote from the Australian study. “All told, our results indicate that claims that extending DST will significantly decrease energy use and GHG [green house gas] emissions are at best overstated, and at worst carry the wrong sign.” So “it’s the thought that counts” in this case just doesn’t work. We’d like to think that extended DST saves us energy, but it doesn’t look like that’s the case.
June 4th, 2008 — Biology, Masters Program
Meta: Sorry about no posts for May - I think I’ll take May off every year. Just way too much going on at work to think about science blogging. But summer is now upon me, so I’ll try to get back to my once a week posting. Tonight’s post is my first assignment for my summer course on scientific writing. We were supposed to choose a science article from a “popular” website and compare that article to the actual report from the science study. As a woman who consumes red meat, this particular article caught my eye. What follows are summaries of the two articles and my thoughts on how I thought the “popular” article did.
R. Stein, Breast cancer risk linked to red meat, study finds. Washington Post, November 14th, 2006. http://www.washingtonpost.com
Scientific article at http://archinte.ama-assn.org
Washington Times Article:
In “Breast Cancer Risk Linked To Red Meat, Study Finds” by Rob Stein, the author summarizes the study by Eunyoung Cho et al on breast cancer and red meat intake by premenopausal women. Stein starts out by stating that younger women may be at a higher risk for one form of breast cancer if they eat red meat. Then he summarizes the study’s method – number and age range of participants, duration of the study - and the overall findings. Over 90,000 women in their 20s, 30s, and 40s were studied over 12 years and the women who consumed the most red meat were at twice the risk of women who ate it infrequently. Once he’s summarized the study, he then spends time going into more detail about the study and the findings. (This is often the way news articles are written – get everything you want to say in the first couple of paragraphs in case your editor chops off the ending bit or in case readers stop reading.)
Some of the things Stein writes about include the fact that this study was the first to concentrate on type of breast cancer and red meat intake and that more research is required “to confirm the association.” Stein also quotes some of the researchers in the study (which is an advantage these reporters have over us – access to the researchers for comment). He includes some statistics about breast cancer and how it affects women. A quote from a cancer expert not linked to the study is also in the article.
The article continues by discussing suggestions on how red meat might affect that particular type of cancer. It also discussed some of the shortcomings of other research on breast cancer and red meat. At this point, the article went into even more detail about the study using specific numbers and findings (though still not getting into the statistical language of the original report). The article concludes with quotes both praising the study and criticizing the study.
Actual Scientific Report:
In the article at the Archives of Internal Medicine, the report begins with an abstract summarizing the study, then goes into detail. According to the researchers, not enough research has been done on younger women and breast cancer. The study focused on the red meat intake of premenopausal women and differentiated between two types of breast tumors – hormone receptor positive and hormone receptor negative. From what the researchers could tell, this was the first study that would examine red meat intake and type of breast cancer.
The study used the Nurses’ Health Study II for its participants. Starting with over 100,000 women, once they removed people who did not return surveys, people who had implausible answers or who left too many blanks on the survey, and people who already had cancer, they wound up with just over 90,000 participants. The researchers sent out food frequency questionnaires to the participants in ‘91, ‘95, and ‘99. Every two years, they sent out questionnaires to identify any new cases of breast cancer in the studied population.
Statistical analysis was done on the findings from the questionnaires. They divided the women by red meat intake and their risk for contracting cancer was compared to the rate of those eating the least red meat. They included other variables in the statistical research, including tobacco use, body mass index, height, family history, etc.
The data was obtained over twelve years and in that time, 1021 cases of cancer were reported, but only 789 cases could be split into hormone receptor positive and hormone receptor negative. 512 cases were hormone receptor positive and the other 167 cases were hormone receptor negative. There was no statistically significant correlation with hormone receptor negative tumors; however, hormone receptor positive tumors did have a significant correlation with high red meat intake.
When they looked at types of red meat and breast cancer, two types did not have statistically significant correlations: bacon and sandwich meat. (They still had a positive correlation, but the results weren’t statistically significant.)
Comparison/Criticism:
I thought that the article by Stein did a pretty nice job of summarizing the findings from the study. However, I was saddened by a complete lack of perspective. It never says what the actual risk is, and that it’s small (albeit statistically significant). “Nearly double” was still only a 1.97% increase. (With the 95% confidence interval being 1.35-2.88, the “actual” threat could be as low as 1.35 – not much bigger than the risk associated for the low meat-eaters.) Saying that women who eat a lot of red meat have twice the risk of women who eat little sounds really scary. But these chances are all less than a two percent chance. I think throwing that perspective into the article would have helped make it less of a scaremonger type of story. I also wish Stein would have talked briefly about the two types of breast cancer covered in the story.
At the end of the article, Stein quotes “the opposing side” to the issue. I’m all for hearing all sides to an issue, but if you look at the quote, you’ll notice it’s not addressing this study.
But noting that earlier studies reached the opposite conclusion, Randall D. Huffman, vice president for scientific affairs at the American Meat Institute, said that research into “diet and health is known for its fluid and often contradictory conclusions. This study is a perfect example of that.”
Considering the “earlier studies” didn’t differentiate between hormone receptor breast cancers, it’s a bit irresponsible to denounce this one compared to the others. I think it’s good to state all sides to a story, but in this case, there ARE no “earlier studies” which contradict the findings and saying that there are is irresponsible. So first our author scares women into thinking they have twice the risk of, well, vegetarians, and then he dismisses it based upon earlier (nonexistent) studies.
Had I written this article, I think I would have focused a little more on the types of breast cancer in the study and explained a little on the percentage of risk. As a pre-menopausal woman who eats red meat (although not regularly) I want to know more about this possible connection. I hope that more studies are done on this. With only 512 actual cancer cases that seemed to have a positive correlation, there really isn’t much data yet. And how reliable is the data? People reporting on food they’ve eaten throughout the year – I’d be doubtful that I’d remember well enough to do a survey sufficient for this type of research. I want to know more information about types of meats and how they are cooked. (Although I was hearted that bacon and sandwich meat weren’t statistically significant, it probably just indicates that there were fewer sandwich/bacon eaters in the survey rather than that those meats are “safer” than other preparations.)
Another thing I would have done, if it were possible, is actually linked to the study in question. Although your average reader of The Washington Post probably isn’t interested in reading the original report, there would be some who ARE interested, and the effort should be made so that they can find out more information.
Despite my criticisms and “I’d've done it THIS way” comments, I did think the article did a nice job on summarizing a study that had a lot of technical terms and statistical information. I just had a statistics class last semester and even I found it difficult interpreting the data. Had I read the original study last summer, I wouldn’t have understood a word of the statistical findings. So it was good to have someone interpreting that data for me (even though I think he simplified it too much). The reminders that this was just preliminary were frequent, which I think is a good thing. Nonscience people have a tendency to either take what a science article says to heart, or disbelieve anything a science article says. Explaining why it’s good to be skeptical of the findings is always a good thing to include in an article about a first time study. Indeed, since I began this Masters program, I’ve become a better skeptic and intend to have some of that rub off on my students.
April 30th, 2008 — Chemistry
Acids and bases are found throughout nearly every home. Carbonated beverages have carbonic acid (a weak acid) in them. Drain cleaners usually have sodium hydroxide (a strong base) as a main ingredient. Window cleaners are often based upon ammonia solutions (a weak base). Your own stomach has hydrochloric acid (a strong acid) in it.
Acidity and alkalinity (basicity?) in their simplest definitions are based upon hydrogen ion concentrations. Acids have high hydrogen ion concentrations and bases have low hydrogen ion concentrations. And both of these are in comparison to water, which has (at room temperature) a particular hydrogen ion concentration when it is pure. At room temperature, pure water (deionized or distilled water which hasn’t had a chance to dissolve any gases from the air) has a concentration of hydrogen ions of 1.00 x 10-7M.
For readers who haven’t had any chemistry, or for whom its been awhile, I might as well have just been speaking Martian. First of all, hydrogen ions are hydrogen atoms which are missing one electron. Water (H2O) molecules are good at separating into hydrogen ions and hydroxide ions (H+ and OH-) but not very many molecules actually do this at any point in time. Approximately one molecule in every half a billion molecules does this splitting into hydrogen and hydroxide ions.
Concentration in chemistry is measured in several ways, and I used the value M (Molar) above. Molar stands for moles of solute per liter of solution. A solute is a chemical dissolved in another chemical (the dissolvee, in other words). A solvent is a chemical that does the dissolving (the dissolver). And the solution is the solute and solvent mixed together. A mole is 6.02×1023 molecules (and that’s a LOT of molecules!) So a concentration of 1.00 x 10-7M means there are 0.0000001 moles of hydrogen ions in one liter of water (about 55.6 moles of water).
Now, if you have a .1M sample of hydrochloric acid (about ten times more concentrated than your stomach acid) you’ll have .1M of hydrogen ions in the solution. That’s a million times the number of hydrogen ions in pure water. Scientists use a shorthand way of describing hydrogen ion concentrations which you’ve probably heard of before: pH. When I was a kid, I always wondered why pH was written that way - why the big H? Well, the H is the symbol of hydrogen. The meaning of p in pH is a bit more cloudy, but one way to look at it is “potential.” pH is the negative log of the hydrogen ion concentration (-log[H+]).
Sorry, I just slipped back into Martian, didn’t I? Log or logarithm is a mathematical tool we can use to look only at the power of ten in a number. For example, 106 becomes 6, 10-7 becomes -7, 0.1 or 10-1 becomes -1. Since most hydrogen ion concentrations are less than 1M (except for highly concentrated acids), most logs of the concentration would wind up being negative numbers. And who wants to remember a bunch of negative numbers? So that’s why pH is the negative log of the hydrogen ion concentration. Water’s hydrogen ion concentration at room temperature (1×10-7M) becomes +7 once we take the negative log of it. Hmmm, pH of 7, isn’t that what we call neutral? 0.1M hydrochloric acid has a pH of 1 while your stomach acid has a pH around 2 (so it’s a concentration of 0.01M or 1×10-2M).
I was prompted to write this entry after a friend of mine pointed out a “bad science” passage in a recent New York Times article. He was pointing out the bad usage of the word “ions” but I immediately pounced upon their description of the pH scale being from only 0 to 14. When I purchase hydrochloric acid for my laboratory, I buy the 12M concentration (which is 1.2×101M). Taking the log of 1×101, you’d get -1. So 12M hydrochloric acid would have a pH value smaller than 0. (18M sulfuric acid has an even smaller pH.)
So the pH scale isn’t just 0 to 14. Any strong acid with a concentration greater than 1M would have a pH smaller than 0. Any strong base with a concentration greater than 1M would have a pH greater than 14. (2M sodium hydroxide would have a pH of 14.3, for example). Neutral water would have a pH of 7 (though tap water is usually around 5 or 6 due to dissolving carbon dioxide from the air and becoming slightly acidic). Bases have pHs greater than 7. Acids have pHs lower than 7.
Now, because of the logarithmic relationship in pH, each number you go up or down in the scale, you’re really going up by 10 or down by 10. A carbonated beverage with a pH around 4 is 10 times more concentrated (hydrogen-wise) than a juice with only a pH around 5, for example. Your stomach (pH around 2) is 1000 times less concentrated (hydrogen-wise) than the 12M hydrochloric acid that I buy (pH around -1).
I hope, in a future blog entry, to discuss some other logarithmic scales that are used in people’s daily lives, such as the Richter scale in earthquake strength determination and the decibels used for sound intensity measurement. But I think I’ve spoken enough Martian for one day.
April 23rd, 2008 — Misconceptions
*ouch* Sorry for the bad pun in the title. But I wanted a catchy title for this post about Water as a Diet Aid. I’ve had many people tell me just how helpful water is in a diet. “It’s common sense,” they tell me, “If you drink cold water, your body uses energy to warm it up and then all that water makes you feel fuller.” The optimist in me thinks “Yeah, that makes sense - maybe I should drink lots & lots of water and finally lose some weight!” The scientist in me, however, says “where’s the evidence?”
So, I’ve decided to seek out evidence - does water help you lose weight? In the simplest terms, you lose weight by using more energy than you take in. If you swap beverages that have Calories (or joules) with water (which has no Calories), that will at least reduce some of the energy that you take in, provided you don’t replace those Calories with other foodstuffs. But if you’re a cheapskate like me who drinks water during meals (because it’s free), would adding MORE water to my diet help me lose weight?
The Cold Water Diet by Douglas Silver Porter was originally published in 2002 and states much of the same “common sense” stuff that my friends had been telling me about Water and Dieting. He does warn about leaching vitamins if you drink too much water and recommends seeing a doctor before changing your diet, so that was good advice. However, he cites no studies performed on water and dieting or, indeed, about any of the claims that he makes in the article. I think the best advice on the page is “In fact, it’s good advise [sic] to be a tad skeptical of everything you’re told.” I agree with you there, Douglas!
The World’s Best Diet Aid by Susie Michelle Cortright agrees with The Cold Water Diet in saying that water is an appetite suppressant. The article talks more about the problems of dehydration than about the benefits of water during weight loss, however. She even has “experts” on her side. “Experts say we lose 1 to 2 pints of water each day just in the process of exhaling.” Really Susie? Which experts? You didn’t cite any of them. (I’ve been trying to find the original article, hoping that maybe it cites her sources - if you can find it online, let me know.)
I think I know why neither of the above diet sites were able to cite their experts. A recent study reported by Negoianu and Goldfarb in The Journal of the American Society of Nephrology (June edition - editorial preprinted online) asserts that there just aren’t enough studies/experiments on how water affects caloric intake/burning calories. Why haven’t studies been done on how water consumption affects obesity? Why are we simply assuming effectiveness or relying on anecdotal evidence? Well, as they further went on to say, no one holds a patent on water, so who would pay for the clinical trials required to settle the matter once and for all? In the final paragraph of their editorial, they summed up their findings from the research they’d done:
There is no clear evidence of benefit from drinking increased amounts of water. Although we wish we could demolish all of the urban myths found on the Internet regarding the benefits of supplemental water ingestion, we concede there is also no clear evidence of lack of benefit. In fact, there is simply a lack of evidence in general.
So what does this mean for those of us hoping to lose weight? Do we keep drinking our eight 8 oz. glasses of water every day in the hopes that Douglas and Susie are right? Personally, I’ll have water with my meals and drink it when I’m thirsty. And to lose weight, I think I’ll try the “tried and true” method - eating fewer calories than I burn in a day (AKA, eat right and exercise).
April 16th, 2008 — Chemistry
I like to make statements that make people think. When I teach about molecular attraction, I like to tell my students that “like dissolves like because opposites attract.” Then we discuss what that all means. So, what does that mean?
I’ll start with the idea of “opposites attract.” This expression has been quite ingrained in our society, even to discussing romantic couples. “Well of course he’s going out with her. Opposites attract, you know.” The expression in the world of science is about electromagnetic interactions. Positively charged particles attract negatively charged particles. The north pole of a magnet is attracted to the south pole of another magnet. Opposites attract and likes repel. Point the north pole of a magnet to another magnet’s north pole and the two magnets will try to move further apart.
So, if opposites attract, why do we also have a statement about “like dissolves like”? Oil and water don’t mix, but oil and grease do. Water and vinegar mix, but vinegar and oil do not (which is why one has to shake up vinaigrette dressing every time you take the bottle out of the fridge). Water and vinegar are “like” while water and oil are not. What makes water and vinegar “like”? Both water and vinegar are polar molecules. Likewise, oil and vinegar are nonpolar molecules.
If you’ve read previous posts from this blog, you may have encountered my post about chemistry jokes. In that post, I describe what polarity is in order to explain my joke about why white bears dissolve in water. (Because they’re polar bears.) I liked that expression so much, I’m going to quote it in this post.
The term polar means that one side of an object is “opposite” of the other. We use “polar” in magnetism (north and south poles of a magnet) and in electricity (a molecule with one side more positive and the other side more negative is a polar molecule). Water is a polar molecule. It is kidney-bean shaped with the oxygen in the center and the two hydrogens 109° from each other. The oxygen is more negatively charged than the hydrogens, and the asymmetry gives the molecule a positive side and negative side to it. Other polar molecules would be attracted to the polar water molecules - the negative sides attract to positive sides and vice versa.
So in a polar molecule, there’s a side that’s positive and a side that’s negative. Since opposites attract, other negative objects (or sides to other molecules) can attract to the positive side and positive objects to the negative side. Vinegar is a polar molecule like water, so positive sides of vinegar molecules stick to negative sides of water molecules, etc. Opposites are attracting. Likes are dissolving. Hmmm, go figure.
In nonpolar molecules like oil and grease, the molecules don’t have positive or negative sides - they’re neutral all over. Nothing to attract to polar molecules. So the question then becomes “why do they stick to each other?” Once again, it’s about charges.
Electrons randomly move around in all molecules, polar and non. Sometimes in a molecule of a nonpolar compound, more electrons will be on one side more than on the other, making a temporary negative side to that molecule (and subsequently a temporary positive side on the other side of the molecule). That temporary negative side causes electrons in a nearby molecule to repel and move further away in their molecule. The second molecule experiences an induced temporary polarity. This fluctuates throughout the molecules of the nonpolar compound and allows the molecules to “hang out” together. If you want to read more about the phenomenon, check out the following websites discussing dipole-dipole interactions and dispersion forces (collectively called van der Waals forces).
So, if you have a grease stain on your shirt, water won’t be able to dissolve it away. However, rather than use gasoline or oil, try a very special molecule which plays on both sides of the fence - soap. Soap is a long molecule that has one side which is polar and another side which is nonpolar. The polar side sticks to water and the nonpolar side sticks to grease. For more about soap (and how you can make it yourself) check out WaltonFeed’s soap making page. They’ll caution you on the site, but I’ll add to the caution - be careful when using lye (sodium hydroxide) when making soap. It’s a very caustic chemical and is something you don’t want on your skin or eyes.
