Science and Technology links (September 22th, 2017)

Mass is preserved. When you lose fat, where does the fat goes? It has to go somewhere. No, it is not transformed in “energy” or “heat”. Neither “energy” nor “heat” have atomic mass. I asked the question on social networks and most people got the wrong answer. This YouTube video gives the correct answer.

I had been assuming that the US consumption of electricity was on the rise. I have gadgets everywhere around me, these use electricity, right? Actually, no, electricity usage, in absolute value, is stagnant in the US, which means that the per capita usage is down:

Economic growth in advanced economies does not require increased energy consumption. Real GDP rose 12.7% in the U.S. between 2008 and 2015. During the same time period, electric consumption declined by 0.3%.

Climate scientists badly failed to predict CO2 emissions:

Global CO2 emission intensity increased despite all major scenarios projecting a decline.

Influential climate scientists have also revised their predictions:

Computer modelling used a decade ago to predict how quickly global average temperatures would rise may have forecast too much warming, a study has found. (…) The Earth warmed more slowly than the models forecast, meaning the planet has a slightly better chance of meeting the goals set out in the Paris climate agreement, including limiting global warming to 1.5C above pre-industrial levels. (…) The study, published this week in the journal Nature Geoscience, does not play down the threat which climate change has to the environment, and maintains that major reductions in emissions must be attained.(…) But the findings indicate the danger may not be as acute as was previously thought.

So you think you should take your antibiotics even after you feel fine? No. Exposing your body to antibiotics longer than needed is counterproductive, as it helps develop antibiotic resistance. Doctor Brad Spellberg is the chief medical officer for the Los Angeles County, and we writes:

There are some chronic infections, such as tuberculosis, where you do indeed have to take long courses of antibiotics, not to prevent resistance but rather to cure the infection. But for most acute bacterial infections, short courses of antibiotics result in equivalent cure rates and with less chance of causing the emergence of antibiotic resistance among the bacteria in and on your body.

Llewelyn et al. (2017) write:

However, the idea that stopping antibiotic treatment early encourages antibiotic resistance is not supported by evidence, while taking antibiotics for longer than necessary increases the risk of resistance.

(Source: HackerNews).

Uber has taken the world by storm, using a small mobile app to allow people to either offer cab services or call a cab service, without the infrastructure that normally supports cab services. The City of London will not renew Uber’s license. The government fears that Uber is a threat to Londoners’ safety and security.

Human beings’ death rate follows a Gompertz’ law which means that the probability that you will die goes up exponentially, year after year. This explains why, even though there are billions of us, none of us get to live beyond 120 years old. Not all living beings follow a Gompertz’ law. Plants do not. However, wooden utility poles do follow a Gompertz’ law just like us.

P. D. Mangan reports that exercise helps keep cancer away:

Exercise prevents cancer (…) A recent meta-analysis found up to 42% less risk for 10 different cancers, including esophageal, liver, lung, kidney, and many other cancers. (…) An interesting question is how exercise prevents cancer, and some recent research sheds light on this. (…) Fat tissue generates cytokines that promote the proliferation of cancer cells, and physical activity diminishes or abolishes the effect, which is dose-dependent, i.e. more exercise means less cancer promoting cytokines. (…) In animals (mice) that were implanted with tumor cells, voluntary running reduced tumor growth by over 60%. The researchers believe that exercise mobilized natural killer (NK) cells, which attack cancer.

Published by

Daniel Lemire

A computer science professor at the University of Quebec (TELUQ).

4 thoughts on “Science and Technology links (September 22th, 2017)”

  1. Regarding cancer and exercise.

    Unfortunately you claim about about up to 42% cancer risk reduction due to exercise is misleading.
    Yes in Moore et al one rare type of cancer was reduced with 42% but the general picture was hazard ratios around 80-90%. That was between the 10 percentile and the 90th percentile of exercise intensity , meaning thats it’s a comparison between the very most inactive people and the most active.

    I thinks it important since unrealistic numbers makes some believe that healthy living can eliminate the risk of diseases, which is unfortunately fare from the truth.

    1. Thanks for the analysis.

      Please don’t mischaracterize my position: this post is a list of links and the quote you refer to as my quote is from the linked article. My commentary is to the effect that exercise seems to help with cancer.

  2. For the energy use – while electricity consumption is down, what do we know about other forms of energy use? Transportation is probably up – and electrification is probably still a rounding error in that field. Use of gas, coal (coke) directly in industry – is that up? Obviously it must be as CO2 is still increasing.

    To suggest that economic growth does not require increased energy might be relying on incomplete data.

    1. It is always difficult to measure something as vague as “energy use”. However, electricity is not some kind of obsolete form of energy that is being replaced. If total energy use was way up in the US, common sense dictates that electricity use would increase.

      We have a strong hint that energy use is uncoupled from GPD growth.

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