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Factors in Aircraft Accidents

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Just some lists of things that increase the probability of an aircraft accident.

Experts have probably calculated exact risk ratios for these different, well-established factors:

  • Improper maintenance
    • Extension of maintenance intervals beyond manufacturer recommendations
    • Opting to defer replacement of noticeably worn parts
    • Not following manufacturer repair instructions
    • Part substitution (using parts that differ slightly from official specifications)
  • Bad weather (ice, convective storms)
  • Limited visibility (night, fog)
  • Human error
    • Assuming increased risk due to desire to be at destination
    • Improper use of checklists (checking items before they are performed)
    • Skipping “rote” checks and safeguards because they rarely reveal issues
    • Changing plans mid-flight (increases cognitive burden while plane is in motion)
    • Miscommunication (language barrier, being overly deferential to captain or traffic control)
  • Lax safety culture
    • Inadequate classroom instruction
    • Skipping of double-checking (when warranted) by second individual or supervisor
  • Airport infrastructure issues
    • Inadequate regulation of construction
    • Inadequate de-icing
  • Computers
    • Burdensome number of (or contradictory) errors reported to pilots
    • Too many sensor malfunctions (distrust of computer-reported errors)

If I had to add to this list with a few guesses of my own, I’d add that these are likely factors:

  • Fatigue
  • Regulatory capture of governmental regulatory bodies by operators (e.g., easy approval of maintenance interval extensions, too-friendly relationships)
  • Social and career consequences of whistle-blowing
  • Corporate cultures that reward metrics that are at-odds with safety (operators, airports, airplane manufacturers, etc.)

And there are some hypothetical, debated factors as well:

  • Complexity

Upgrading from MariaDB 10.2 to MariaDB 10.3 on CentOS 7

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Just updated MariaDB from 10.2 to 10.3 on multiple servers using Red Hat’s Software Collections (https://www.softwarecollections.org/en/). Used the following commands. Might be of use to someone, good luck!

# Install MariaDB 10.3
yum install rh-mariadb103-mariadb-server
yum install rh-mariadb103-mariadb-server-utils

# Add MariaDB 10.3 to $PATH
scl enable rh-mariadb103 bash
source /opt/rh/rh-mariadb103/enable

# Stop 10.2 server, copy database, set permissions, start 10.3 server
systemctl stop rh-mariadb102-mariadb.service;
cp -r /var/opt/rh/rh-mariadb102/lib/mysql /var/opt/rh/rh-mariadb103/lib;
chown -R mysql:mysql /var/opt/rh/rh-mariadb103/lib/mysql;
systemctl start rh-mariadb103-mariadb

# Upgrade tables
mysql_upgrade -p[PASSWORD]

# Set 10.3 to start on boot, disable 10.2
systemctl disable rh-mariadb102-mariadb
systemctl enable rh-mariadb103-mariadb

# Add 10.3 to paths on reboot (and remove 10.2) 
rm /etc/profile.d/rh-mariadb102.sh
cp /opt/rh/rh-mariadb103/enable /etc/profile.d/rh-mariadb103.sh

Don’t forget to edit your new database configuration file, which is located at /etc/opt/rh/rh-mariadb103/my.cnf. Your old configuration will be at /etc/opt/rh/rh-mariadb102/my.cnf. The /my.cnf.d/ subdirectory at the same location may contain additional configuration files.

List of United States Mystery Diseases

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This is just a list of diseases endemic to the United States for which there is no known cause nor cure. As of 2018, diagnosis of these diseases is still based on signs & reported symptoms, not on any blood tests or other tests. The list:

  • non-celiac gluten sensitivity (NCGS)
  • acute flaccid myelitis (AFM)
  • irritable bowel syndrome (IBS)
  • chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME)

Some of these may actually be grouping multiple diseases under one label. For example, IBS comes in two varieties – IBS-C and IBS-D, the first constipative and the second diarrheal. Although the mechanisms that lead to these diseases’ development may be similar, it seems possible that they are caused by two different mechanisms, either two different viruses or two different genetic predispositions.

Interestingly, CFS/ME and AFM, and IBS all have patients who state that the disease began after a bad infection.

Also interestingly, the first reaction of many physicians to these diseases is one of disbelief — as if a disease not in a textbook does not exist. The second instinct upon seeing a disease that “does not exist” is to suspect mental illness — the patient just needs a psychologist/therapist. Sometimes this is appropriate — for example, someone with an unmanaged anxiety disorder may display the symptoms of IBS-D — their bowels are forever aquiver. But often this is inappropriate — when someone gets the flu we do not attribute their lack of energy to “deep-seated emotional issues.”

This list is surely not exhaustive, but it does represent the “top diseases” — those that receive the greatest news coverage.

Upgrading from MariaDB 5.5 to MariaDB 10.2 on CentOS 7

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By default, CentOS 7 uses MariaDB 5.5. Newer versions of MariaDB are available from Software Collections. Here is the code I used on a few different servers to change the SQL database version from MariaDB 5.5 to 10.2:

# Install MariaDB 10.2. You might need to add the Software Collections repo beforehand.
yum install rh-mariadb102-mariadb-server


# Stop MariaDB 5.5
# Copy databases to MariaDB 10.2
# Set owner
# Start MariaDB 10.2
systemctl stop mariadb; cp -r /var/lib/mysql /var/opt/rh/rh-mariadb102/lib; chown -R mysql:mysql /var/opt/rh/rh-mariadb102/lib/mysql; systemctl start rh-mariadb102-mariadb

# Add MariaDB 10.2 to path
scl enable rh-mariadb102 bash

# Check that PATH is set correctly
which mysql_upgrade

# If path to mysql_upgrade is /usr/bin/, then it wasn't successfully changed. Try running:
source /opt/rh/rh-mariadb102/enable

# Upgrade the copied databases
mysql_upgrade -p[PASSWORD]

# Disable MariaDB 5.5 to start on boot
systemctl disable mariadb

# Enable MariaDB 10.2 to start on boot
systemctl enable rh-mariadb102-mariadb

# Add MariaDB 10.2 to path on boot
cp /opt/rh/rh-mariadb102/enable /etc/profile.d/rh-mariadb102.sh

Don’t forget to edit your new database configuration file, which is located at /etc/opt/rh/rh-mariadb102/my.cnf. Your old configuration will be at /etc/my.cnf.

Good luck!

Differences Between Canada and New England

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My family and I have traveled to eastern Canada about 12–24 times, from Toronto to Nova Scotia. Here are some differences we noticed between Canada and New England:

Advantages to Canada

  • Fewer people
  • Cleaner air
  • Higher probability of strangers approaching and/or talking to you
  • Fewer potholes, it seems

 

Disadvantages of Canada

  • (For those who dislike social interaction) Higher probability of strangers approaching and/or talking to you
  • Some people don’t speak English
  • Apparently, still a constitutional monarchy

 

Other Differences

  • Tobacco products are affixed with graphic images of product health consequences (e.g., mouth cancer)
  • More pine trees
  • Some people are native French speakers
  • Higher beaver and wolf populations
  • Native Americans are called ‘First Peoples’

 

There are probably some other differences, too.

DeepDreaming of Shibas

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DeepDream (image processing software) employs a CNN (convolutional neural network) to re-draw one input image and in the style of a second input image.


Figure 1. Input image of Yoshi, lying down against a fence. Full disclosure: neural networks have in the past classified him as ‘orange cat’.

 

Figures 2-12. Output images of Yoshi, after being re-drawn in various visual styles by DeepDream.

You can do this yourself here.

Comparing Nasal Decongestants

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Nasal congestion is a common ailment that is not always easy to resolve. You may think that you have only one or two options when it comes to medicating this condition, but there are actually many types of nasal decongestant. Here is a quick comparison:

TypeAdvantagesDisadvantages
Oral formulations (pills)Decongestant effect evenly applied; reaches all nasal tissueTake hours or days to work
Intranasal sprays (liquid)Take minutes to workDoes not reach all nasal tissue - only tissue it touches
Intranasal inhalers (gas)

Here is a detailed comparison:

Drug nameLegal statusBrand name(s)EffectsRebound congestion?ReviewTechnical details
Oral formulations (pills)
pseudoephedrineOTC (restricted*)Sudafed®, Wal-Phed®Noticeable after ~1 hour, full effect after ~2 hours. Lasts ~2-3 hours.None noticeable.Pseudoephedrine remains the gold standard oral medication for nasal decongestion. Its side effects are milder than other sympathomimetics, such as ephedrine.substituted amphetamine (sympathomimetic); *In U.S., requires purchase from pharmacy counter and presentation of state I.D.
phenylephrineOTC??????I experienced nausea and no decongestant effect from this drug. Results may vary so this may be worth trying, anyhow.
ephedrineOTC (restricted*)Bronkaid®, Primatine®??????Because ephedrine has a stronger bronchodilator effect than nasal decongestant effect, this drug is not recommended (or marketed for) nasal decongestion.substituted amphetamine (sympathomimetic) *In U.S., requires purchase from pharmacy counter and presentation of state I.D.
montelukast℞ onlySingulair®Noticeable in ~3-7 days, full effect in ~14 days. Lasts ~3 days.Not noticeable.Montelukast causes a mild increase in air flow that is present all day long. It is effective only for those experiencing leukotriene-instigated airway inflammation, due to conditions such as allergic rhinitis or allergic asthma.antileukotriene; ℞ due to suicidal ideation in small fraction of patients; FDA declined to make OTC in 2014.
Intranasal sprays (liquid)
phenylephrineOTCWal-Four®Fastest decongestant. Noticeable in 1-4 minutes, full effect after ~20 minutes. Lasts 3-4 hours.???In its nasal spray form, phenylephrine seems less likely to cause burning than oxymetazoline. It is also slightly faster-acting than oxymetazoline, but lasts only 1/3 as long (4 hours instead of 12 hours). If used before sleeping, you may wake up to find you need to re-use.
oxymetazolineOTCAfrin®Noticeable in ~5 minutes, full effect after ~20 minutes. Lasts 12 hours total.Next day causes runny nose and mild reboundThe fastest-acting, longest-acting nasal decongestant. Effectiveness can lead to user dependence (rhinitis medicamentosa)
Intranasal inhalers (gas)
L‑methamphetamineOTCSinu Inhaler™Noticeable after ~10 minutes, full effect after ~30 minutes. Lasts ~2 hours total.Not noticeable.Instead of acting directly to cause vasoconstriction, levomethamphetamine causes a temporary increase in the release of catecholamines, thereby indirectly causing mild decongestion. For some reason, sometimes it is moderately effective, and other times completely ineffective. More expensive than intranasal sprays, so that combined with irregular efficacy may explain why this is not a popular decongestant.Also labeled as: levomethamphetamine or levmetamfetamine; L-enantiomer form of methamphetamine -- legal in U.S.
propylhexedrineOTCBenzedrex®2 hoursNot noticeableHarsher than levmatamfetamine nasal inhaler, but slightly more effective.

Of course, it would be a good idea to consult with a physician — some of the above medicines are contraindicated in the young or elderly. Good luck!

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