Relax? Not yet

Written on 18 April 2020, 07:45pm

Tagged with: , , , ,

My view on the recent study arguing that the lock-down measures implemented in Belgium should be relaxed to match the ones in the Netherlands, which lead to similar infection numbers. For completion, the 3 main differences between the two countries are:

  • no legal enforcement of the lock-down in the NL
  • all shops remain open in the NL
  • telework is encouraged, but not mandatory in the NL

Note: For the sake of readability, I will add the relevant links at the end of the post.

What I liked in the study

  • the dependency between the policy, human behavior and outcome
  • the use of Google mobility data

The two premises

  • I pretty much agree with the first one – about the complexity of the epidemic models and the fact that the Belgian government is not very transparent in sharing all the data. But we should not underestimate the importance of the scientists working together with the decision-makers.
  • However, I do not agree with the second premise: that the models need precise data in order to work. Scientists routinely work with incomplete or imperfect data. Confidence intervals, margins of error, type I and II errors are all part of the game. This is not a perfect world.

The Russell problem

Written on 18 February 2020, 12:16pm

Tagged with: ,

The Russell problem is one of the most difficult problems that the humankind needs to solve soon:

How one can convince humanity to consent to their own survival.

Bertrand Russell

We are slowly, but surely destroying our planet. And with it, since we don’t yet have a planet B, we are destroying our species. The effects are already here. While there is a large consensus that the consequences of our behavior are irreversible, we can still slow down the whole process. It might be just enough to find a last-minute solution (sometimes pressure helps) or simply to find another home and ensure the survival of the humankind.

Here are a few types of people that have to be convinced:

  1. The denialists: They argue there is no climate change. Essentially flat-earthers, or anti-vaxers. Can’t and (unfortunately) won’t be convinced.
    Passive and uneducated.
  2. The hangoners: Yes, the climate change is probably real. But hang on, hang on, we don’t have to rush into doing anything. There’s still plenty of time left, and we might make things worse if we actually do something. So let’s wait. And then let’s wait more.
    Passive; consider themselves educated.
  3. The defetists: we’re screwed anyway. So let’s party like it’s 1999…
    Passive. More educated.
  4. The youfirsters. Sure, we’re going down, but you do something first.
    Passive. Education irrelevant.
  5. The trolls. I don’t care if we’re going down, I just want to make fun of Greta.
    Passive and uneducated.
  6. The ostriches. Right, we know that the birds don’t actually bury their head into the sand, but their human equivalent do. They hope that the climate change is just a bad dream and probably believe in Captain Planet.
  7. The average Joes. Vaguely aware about the climate change, but their efforts are limited to recycling paper and glass.
    Hardly active, mildly educated.
Made with ❤ in

Random links #19

Written on 12 February 2020, 04:22pm

Tagged with: , , , ,

3 reasons to go vegetarian/vegan/flexitarian

Why do the helicopters crash more often?

  • they are used in risky situations: search and rescue operations, military, medical evacuation, etc
  • more vulnerable than planes to bad weather
  • they fly at lower altitudes, so higher risk to hit obstacles and less time to recover in case things go wrong
  • they take off and land more often than the planes (shorter routes)
  • more moving parts, so more possibilities to fail
  • can’t glide
  • a bit more difficult to control than planes

Why the commercial aircraft do not have a parachute?

Well, some of the small planes do. But the commercial aircraft don’t and are unlikely to have in the future because of how physics works:

  • if there would be a single parachute, the shock when it will be engaged will simply destroy the aircraft structure
  • multiple parachutes make things impractical: they would have to be deployed in the same time, would increase the total weight and significantly decrease the payload
  • a parachute system would require a very complex maintenance process (periodic tests, replacements, etc).
  • it would also require a complex safety system to prevent accidental deployment
  • a parachute system for a large airplane (like the Airbus A380 – 850 people or Boeing 747 – 500 people) will have to ditch everything except for the pressurized passenger cabin. Again, not practical, and how do you control where the rest of plane ends when the pilot engages this system?

OK, then why don’t the airlines give parachutes to the passengers?

Simply put, they are unlikely to save lives.

  • first problem: at which stage of the flight do you tell the passengers to use the parachutes? Life vests are simple, everybody knows when to use them. But parachutes?
  • the physics laws prevent the hatch to be opened at high altitudes. So an explosives system would be needed if you want to jump at 35000 feet (10700m)
  • if you still want to jump at that altitude, you would likely enter a thermal shock (negative 60 degrees Celsius) and lose conscience in a few seconds due to the lack of oxygen. Unlikely to land alive.
  • so you will have to blast the door and jump somewhere lower, maybe 15000 feet (4500m). Except – you’re not alone. A few hundreds passengers will try to do the same thing before the plane hits the ground.
  • assuming that the passengers can jump in an orderly manner, and allocating 10 seconds per jump, you would still need around 40 minutes for a 250 passenger plane to be evacuated in mid-air. Only 20 minutes if you open 2 doors.
  • if you manage to jump, you will hope to avoid being sucked into the engines (if you use the front doors) or sliced by the horizontal stabilizers (if you use the back doors). More importantly, you will pray to avoid fatal injuries when the parachute deploys: your plane will probably fly way past the safety jump speed limit
  • BTW, did you ever strap your parachute and actually jump from a plane? And did you ever land by yourself?
  • You see, the chances of coming down alive using a parachute are becoming increasingly small. Not to mention that you might land in the middle of a freezing ocean, with the parachute coming down on you.
  • Also, most of the aircraft accidents happen during takeoff and landing, when the parachutes simply won’t work