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Technology & InternetSci-tech information: The truths of science and technology rumors
Plants won’t Grow near Wi-Fi Router?
The story of five Danish school girls who won a prize with their school experiment that allegedly shows that the electromagnetic radiation of WiFi routers has a negative effect on the germination of garden cress, has been reported by numerous sites on the Internet. Just check the number of Google hits while searching for “wifi cress”. The girls placed twelve plates with cress seeds on cotton in front of a window, watered those regularly an watched the seeds germinate. Between six of the plates WiFi routers were placed. After 13 days the cress was cut and dried and the germinated seeds were counted. A big difference was found. From the seeds which were held under radiation far less had germinated. Evidence for negative effects of WiFi? Nope.
Nice for the girls that they won this prize, but not so great that it’s promoted as a good example of science. It’s not the girls fault, but their study is an excellent example of how pseudo- or bad science can enter the classroom.
It was first published on a Danish website (Google translation) and then picked up by Geek.com and ABC News for instance. Not very critical these reports. Norwegian science journalist Gunnar Tjomlid had a good look at the study design and the report. He found a lot of things which are questionable. I suggest you read his excellent blog yourself (Google translated if you don’t read Norwegian). I will just mention the most important things from it:
The WiFi and control group were not just different because of the presence of the routers. On the pictures in the report it can be seen that also the laptops in the WiFi group were placed quite near to the plates. It’s very likely that this had an effect on airflow and temperature around the plates and that could have an effect on germination, which has nothing to do with the presence of EM-fields. Not properly controlled.
It was obvious what the WiFi group was and what control group. Not blinded.
From communication with the science teacher of the girls Tjomlid learned that their had been two experiments. The first one had the routers only sending out the SSID. A second experiment in which the laptops had been ‘pinging’ each other constantly did not show the dramatic difference in germination. Only the first experiment was used in the report (not completely clear, because the teacher gave contradicting information on this). Publication bias: not reporting negative results.
The reports on blogs illustrated the difference in germination by photographs of plates with cress, one showing a full grown, not radiated, ‘healty’ one and a plate which almost doesn’t show any sprouted seed at all, a radiated, ‘sick’ plate. If you look at the actual reported results, they do not look that shocking: on average the control group had 332 sprouted seeds versus 252 in the WiFi group. Misleading representation of the result in the press.
The plates in a group were not separated in space, so we cannot regard the results of individual plates as independent observations. In fact, you could argue this is an N=2 experiment. Faulty statistical analysis.
The girls stopped the experiment on day 13. Not because that was a predefined moment, but because on that day the control group had reached the maximum height. The problem is that due to a difference in temperature of just a few degrees, it can already take a couple of days for the cress to grow to the same height. If there was indeed a difference in temperature due to the placement of the laptops, it would be likely that the WiFi group could have germinated and grown similar to the control group if it was allowed to grow on for a couple of days. They were just looking for the result they had in their mind beforehand. Biased towards a particular result.
It’s quite clear that based on this experiment, you can’t draw any conclusion on the non-thermic effects of WiFi routers on germination. It’s a pity that the girls had this obviously biased teacher as a supervisor and that their work is now being used by pseudo-scientists as ‘evidence’ that EM-fields are very dangerous, while there is consensus that if there is a risk at all, it’s very low. The faults made can’t be blamed on the girls and let’s hope that this experience doesn’t affect their interest in research. It could even be a very good learning experience, if they are willing to have look at what went wrong, because it has so many aspects of bad science.
Charge Your Phone Faster by Switching to Airplane Mode Before Plugging In?
Rumours said that if you've ever needed to charge your phone but known you had to leave an outlet behind in just a few minutes, put your phone in Airplane Mode first.
There explains that putting your phone into airplane mode turns off all of the wireless radios inside, so while you won't be able to receive calls, use data, or use GPS, you also won't be fighting background processes that use those radios for power while your phone is plugged in. The end result is your phone will charge a little faster, and you'll walk away with a bit more power in your battery than you would otherwise. But this doesn't make any sense. What would really make a difference is just turning off the phone.
Vitamin C for preventing and treating the common cold?
The role of vitamin C (ascorbic acid) in the prevention and treatment of the common cold has been a subject of controversy for 60 years, but is widely sold and used as both a preventive and therapeutic agent.
To discover whether oral doses of 0.2 g or more daily of vitamin C reduces the incidence, duration or severity of the common cold when used either as continuous prophylaxis or after the onset of symptoms, scientists implemented a series of experiments.
The failure of vitamin C supplementation to reduce the incidence of colds in the normal population indicates that routine mega-dose prophylaxis is not rationally justified for community use. But evidence suggests that it could be justified in people exposed to brief periods of severe physical exercise or cold environments.
IGF-1 in milk from rBGH-treated cows ?
Recombinant bovine growth hormone (rBGH) is a synthetic (man-made) hormone that is marketed to dairy farmers to increase milk production in cows. It has been used in the United States since it was approved by the Food and Drug Administration (FDA) in 1993, but its use is not permitted in the European Union, Canada, and some other countries. This document summarizes what is known about the product and its potential effects on health.
The human form of growth hormone, also called somatotropin, is made by the pituitary gland. It promotes growth and cell replication. Bovine growth hormone (BGH), also known as bovine somatotropin (BST) is the natural form of this hormone in cattle.
Recombinant bovine growth hormone (rBGH) or recombinant bovine somatotropin (rBST) refers to bovine growth hormone that is made in a lab using genetic technology. Some rBGH products on the market differ chemically from a cow's natural somatotropin by one amino acid. Both the natural and recombinant forms of the hormone stimulate a cow's milk production by increasing levels of another hormone known as insulin-like growth factor (IGF-1).
Concerns about possible health effects on humans from milk produced using rBGH have focused on 2 main issues.
First, does drinking milk from rBGH-treated cows increase blood levels of growth hormone or IGF-1 in consumers? If it does, would this be expected to have any health effects in people, including increasing the risk of cancer? Several scientific reviews have looked at these issues and are the main focus of this document.
Second, cows treated with rBGH tend to develop more udder infections (mastitis). These cows are given more antibiotics than cows not given rBGH. Does this increased use of antibiotics lead to more antibiotic-resistant bacteria, and is this a health concern for people? This remains a concern, but it has not been fully examined in humans.
Bovine growth hormone levels are not significantly higher in milk from rBGH-treated cows. On top of this, BGH is not active in humans, so even if it were absorbed from drinking milk, it wouldn't be expected to cause health effects.
Of greater concern is the fact that milk from rBGH-treated cows has higher levels of IGF-1, a hormone that normally helps some types of cells to grow. Several studies have found that IGF-1 levels at the high end of the normal range may influence the development of certain tumors. Some early studies found a relationship between blood levels of IGF-1 and the development of prostate, breast, colorectal, and other cancers, but later studies have failed to confirm these reports or have found weaker relationships. While there may be a link between IGF-1 blood levels and cancer, the exact nature of this link remains unclear.
Some studies have shown that adults who drink milk have about 10% higher levels of IGF-1 in their blood than those who drink little or no milk. But this same finding has also been reported in people who drink soymilk. This suggests that the increase in IGF-1 may not be specific to cow's milk, and may be caused by protein, minerals, or some other factors in milk unrelated to rBGH. There have been no direct comparisons of IGF-1 levels in people who drink ordinary cow's milk vs. milk stimulated by rBGH.
At this time, it is not clear that drinking milk, produced with or without rBGH treatment, increases blood IGF-1 levels into a range that might be of concern regarding cancer risk or other health effects.
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