Raising a child costs 13 million calories

That’s right. Somebody actually did the math on that. Kaplan in 1994, to be exact.

The anthropologist and his colleague, Kate Kopischke, looked at how three semi-isolated populations from South America live. Between September 1988 and May 1989, the researchers analyzed several variables meant to shed light mainly on fertility rate and wealth flow. They measured the amount of time spent taking care of children. They estimated the best time to have a second child. They weighed the food of these communities. And then they estimated the caloric intake and expenditure per day per individual.

Human children are unable to provision for themselves until about the age of 18. So most of their caloric intake requirements are provided by their parents. Long story (39 pages) short, Kaplan (1994) concluded that a child relies on 13 million calories provided by the adults. Granted, these are mostly hunter-gatherer communities, so the number may be a bit off from your average American child. The question is: which way? Do American kids “cost” more or less?

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P.S. I was reading a paper, Kohl (2018), in the last week’s issue of Science that quoted this number, 13 million. When I went to the cited source, Hrdy (2016), that one was citing yet another one, the above-mentioned Kaplan (1994) paper. Luckily for Kohl, Hrdy cited Kaplan correctly. But I must tell you from my own experience, half of the time when people cite other people citing other people citing original research, they are wrong. Meaning that somewhere in the chain somebody got it wrong or twisted the original research finding for their purposes. Half of the time, I tell you. People don’t go for the original material because it can be a hassle to dig it out, or it’s hard to read, or because citing a more recent paper looks better in the review process. But that comes to the risk of being flat wrong. The moral: always, always, go for the source material.

P.P.S. To be clear, I’m not accusing Kohl of not reading Kaplan because accusing an academic of citing without reading or being unfamiliar with seminal research in their field (that is, seminal in somebody else’s opinion) is a tremendous insult not be wielded lightly by bystanders but to be viciously used only for in-house fights on a regular basis. No. I’m saying that Kohl got that number second-hand and that’s frowned upon. The moral: always, always, go for the source material. I can’t emphasize this enough.

P.P.P..S. Ah, forget it. P.S. 3. Upon reading my blog, my significant other’s first question was: “Well, how much is that in potatoes?” I had to do the math on a Post-It and the answer is: 50,288 large skinless potatoes, boiled without salt. That’s 15,116 Kg of potatoes, more than 15 metric tones. Here you go. Happy now? Why are we talking about potatoes?! No, I don’t know how many potatoes would fit into a house. Jeez!

REFERENCE: Kaplan, H. (Dec. 1994). Evolutionary and Wealth Flows Theories of Fertility: Empirical Tests and New Models. Population and Development Review, Vol. 20, No. 4, pp. 753-791. DOI: 10.2307/2137661. ARTICLE

By Neuronicus, 22 October 2018

Locus Coeruleus in mania

From all the mental disorders, bipolar disorder, a.k.a. manic-depressive disorder, has the highest risk for suicide attempt and completion. If the thought of suicide crosses your mind, stop reading this, it’s not that important; what’s important is for you to call the toll-free National Suicide Prevention Lifeline at 1-800-273-TALK (8255).

The bipolar disorder is defined by alternating manic episodes of elevated mood, activity, excitation, and energy with episodes of depression characterized by feelings of deep sadness, hopelessness, worthlessness, low energy, and decreased activity. It is also a more common disease than people usually expect, affecting about 1% or more of the world population. That means almost 80 million people! Therefore, it’s imperative to find out what’s causing it so we can treat it.

Unfortunately, the disease is very complex, with many brain parts, brain chemicals, and genes involved in its pathology. We don’t even fully comprehend how the best medication we have to lower the risk of suicide, lithium, works. The good news is the neuroscientists haven’t given up, they are grinding at it, and with every study we get closer to subduing this monster.

One such study freshly published last month, Cao et al. (2018), looked at a semi-obscure membrane protein, ErbB4. The protein is a tyrosine kinase receptor, which is a bit unfortunate because this means is involved in ubiquitous cellular signaling, making it harder to find its exact role in a specific disorder. Indeed, ErbB4 has been found to play a role in neural development, schizophrenia, epilepsy, even ALS (Lou Gehrig’s disease).

Given that ErbB4 is found in some neurons that are involved in bipolar and mutations in its gene are also found in some people with bipolar, Cao et al. (2018) sought to find out more about it.

First, they produced mice that lacked the gene coding for ErbB4 in neurons from locus coeruleus, the part of the brain that produces norepinephrine out of dopamine, better known for the European audience as nor-adrenaline. The mutant mice had a lot more norepinephrine and dopamine in their brains, which correlated with mania-like behaviors. You might have noticed that the term used was ‘manic-like’ and not ‘manic’ because we don’t know for sure how the mice feel; instead, we can see how they behave and from that infer how they feel. So the researchers put the mice thorough a battery of behavioral tests and observed that the mutant mice were hyperactive, showed less anxious and depressed behaviors, and they liked their sugary drink more than their normal counterparts, which, taken together, are indices of mania.

Next, through a series of electrophysiological experiments, the scientists found that the mechanism through which the absence of ErbB4 leads to mania is making another receptor, called NMDA, in that brain region more active. When this receptor is hyperactive, it causes neurons to fire, releasing their norepinephrine. But if given lithium, the mutant mice behaved like normal mice. Correspondingly, they also had a normal-behaving NMDA receptor, which led to normal firing of the noradrenergic neurons.

So the mechanism looks like this (Jargon alert!):

No ErbB4 –> ↑ NR2B NMDAR subunit –> hyperactive NMDAR –> ↑ neuron firing –> ↑ catecholamines –> mania.

In conclusion, another piece of the bipolar puzzle has been uncovered. The next obvious step will be for the researchers to figure out a medicine that targets ErbB4 and see if it could treat bipolar disorder. Good paper!

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P.S. If you’re not familiar with the journal eLife, go and check it out. The journal offers for every study a half-page summary of the findings destined for the lay audience, called eLife digest. I’ve seen this practice in other journals, but this one is generally very well written and truly for the lay audience and the non-specialist. Something of what I try to do here, minus the personal remarks and in parenthesis metacognitions that you’ll find in most of my posts. In short, the eLife digest is masterly done. As my continuous struggles on this blog show, it is tremendously difficult for a scientist to write concisely, precisely, and jargonless at the same time. But eLife is doing it. Check it out. Plus, if you care to take a look on how science is done and published, eLife publishes all the editor’s rejection notes, all the reviewers’ comments, and all the author responses for a particular paper. Reading those is truly a teaching moment.

REFERENCE: Cao SX, Zhang Y, Hu XY, Hong B, Sun P, He HY, Geng HY, Bao AM, Duan SM, Yang JM, Gao TM, Lian H, Li XM (4 Sept 2018). ErbB4 deletion in noradrenergic neurons in the locus coeruleus induces mania-like behavior via elevated catecholamines. Elife, 7. pii: e39907. doi: 10.7554/eLife.39907. PMID: 30179154 ARTICLE | FREE FULLTEXT PDF

By Neuronicus, 14 October 2018

The Global Warming IPCC 2018 Report

The Special Report on Global Warming of 1.5ºC (SR15) was published two days ago, on October 8th, 2018. The Report was written by The Intergovernmental Panel on Climate Change (IPCC), “which is the UN body for assessing the science related to climate change. It was established by the United Nations Environment Programme (UN Environment) and the World Meteorological Organization (WMO) in 1988 to provide policymakers with regular scientific assessments concerning climate change, its implications and potential future risks, as well as to put forward adaptation and mitigation strategies.” (IPCC Special Report on Global Warming of 1.5ºC, Press Release).

The Report’s findings are very bad. Its Summary for Policymakers starts with:

“Human activities are estimated to have caused approximately 1.0°C of global warming above pre-industrial levels, with a likely range of 0.8°C to 1.2°C. Global warming is likely to reach 1.5°C between 2030 and 2052 if it continues to increase at the current rate.”

That’s 12 years from now.

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Extract from the IPCC (2018), Global Warming of 1.5 ºC, Summary for Policymakers. “Observed monthly global mean surface temperature (GMST) change grey line up to 2017, from the HadCRUT4, GISTEMP, Cowtan – Way, and NOAA datasets) and estimated anthropogenic global warming (solid orange line up to 2017, with orange shading indicating assessed likely range). Orange dashed arrow and horizontal orange error bar show respectively central estimate and likely range of the time at which 1.5°C is reached if the current rate of warming continues. The grey plume on the right of  shows the likely range of warming responses, computed with a simple climate model, to a stylized pathway (hypothetical future) in which net CO2 emissions  decline in a straight line from 2020 to reach net zero in 2055 and net non – CO2 radiative forcing increases to 2030 and then declines. “

Which means that we warmed up the world by 1.0°C (1.8°F) since 1850-1900. Continuing the way we have been doing, we will add another 0.5°C (0.9°F) to the world temperature sometime between 2030 and 2052, making the total human-made global warming to 1.5°C (2.7°F).

That’s 12 years from now.

Half a degree Celsius doesn’t sound so bad until you look at the highly confident model prediction saying that gaining that extra 0.5°C (0.9°F) will result in terrible unseen before superstorms and precipitation in some regions while others will suffer prolonged droughts, along with extreme heat waves and sea level rises due to the melting of Antarctica. From a biota point of view, if we reach the 1.5°C (2.7°F) threshold, most of the coral reefs will become extinct, as well as thousands of other species (6% of insects, 8% of plants, and 4% of vertebrates).

That’s 12 years from now.

All these will end up increasing famine, homelessness, disease, inequality, poverty, and refugee numbers to unprecedented levels. Huge spending of money on infrastructure, rebuilding, help efforts, irrigation, water supplies, and so on, for those inclined to be more concerned by finances. To put it bluntly, a 1.5°C (2.7°F) increase in global warming costs us about $54 trillion.

That’s 12 years from now.

These effects will persist for centuries to millennia. To stay at the 1.5°C (2.7°F)  limit we need to reduce the carbon emissions by 50% by 2030 and achieve 0 emissions by 2050.

That’s 12 years from now.

The Report emphasizes that a 1.5°C (2.7°F)  increase is not as bad as a 2°C (3.6°F), where we will loose double of the biota, the storms will be worse, the droughts longer, and altogether a more catastrophic scenario.

Technically, we ARE ABLE to limit the warming at 1.5°C (2.7°F), If, by 2050, we rely on renewable energy, like solar and wind, to supply 70-85% of energy, we will be able to stay at the 1.5°C (2.7°F). Lower the coal use as energy source to single digits percentages. Expanding forests and implementing large CO2 capture programs would help tremendously. Drastically reduce carbon emissions by, for example, hitting polluters with crippling fines. But all this requires rapid implementation of heavy laws and regulation, which will come from a concentrated effort of our leaders.

Therefore, politically, we ARE UNABLE to limit the warming at 1.5°C (2.7°F). Instead, it’s very likely that we will warm the planet by 2°C (3.6°F) in the next decades. If we do nothing, by the end of the century the world will be even hotter, being warmed up by 3°C (5.4°F) and there are no happy scenarios then as the climate change will be beyond our control. That is, our children’s control.

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There are conspiracy theorists out there claiming that there are nefarious or hidden reasons behind this report, or that its conclusions are not credible, or that it’s not legit, or it’s bad science, or that it represents the view of a fringe group of scientists and does not reflect a scientific consensus. I would argue that people who claim such absurdities are either the ones with a hidden agenda or are plain idiots. Not ignorants, because ignorance is curable and whoever seeks to learn new things is to be admired. Not honest questioning either, because that is as necessary to science as the water to the fish. Willful ignorance, on the other hand, I call idiocy and is remarkably resistant to presentation of facts. FYI, the Report was conducted by a Panel commissioned by an organization comprising 195 countries, is authored by 91 scientists, has an additional 133 contributing authors, all these spanning 40 countries, analyzing over 6000 scientific studies. Oh, and the Panel received the 2007 Nobel Peace Prize. I daresay it looks legit. The next full climate assessment will be released in 2021.

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REFERENCES:

  1. The Intergovernmental Panel on Climate Change (IPCC) (2018). Global Warming of 1.5 ºC, an IPCC Special report on the impacts of global warming of 1.5 ºC above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty. Retrieved 10 October 2018Website  | Covers: New York Times | Nature  | The Washington Post | The Guardian | The Economist | ABC News | Deutsche Welle | CNN | HuffPost Canada| Los Angeles Times | BBC | Time .
  2. The IPCC Summary for Policymakers PDF
  3. The IPCC Press Release PDF
  4. The 2007 Nobel Peace Prize.

By Neuronicus, 10 October 2018