In the afternoon I carefully removed the exuviae of the Aphonopelma
seemanni I keep from its burrow. It had started molting
yesterday in the
I carefully moistened the molt with some water and manipulated it to
open it up enough to see the spermathecae (female) or not (male). As
this is a large molt I was able to see the spermathecae with the naked
eye; it's a girl!
I bought this tarantula 7th of March
and this was the first time it molted in my care.
Eight tips to relieve those Postgres headaches
Welcome to this practical, non-exhaustive guide to some of the
common issues you’ll encounter while using Postgres. We’ll go beyond
the basic advice of adding indices to your queries using sequential
scans. There are also a few extra tips for those using the AWS RDS
The concepts of correlation and causation are sometimes confusing to
amateur researchers. In practice, I often saw researchers
considering a correlation as causation and making mistakes in
conclusions. Mathematically, correlation is the necessary but
insufficient condition for causation. In other words, if two things
have causation relationship, these two things must have correlation
relationship as well. However, if two things have correlation
relationship, these two things do not necessarily have causation
In this blog post, I would use an example to talk about the concepts
of correlation and causation, how to verify causation using
experiments, and the caveats in using experiments to verify
In the evening, when checking upon the Aphonopelma seemanni I keep I
noticed that it was upside down in its burrow. This means the
tarantula is going through ecdysis; the shedding of its old exoskeleton.
The tarantula has been restless for about a week or so, getting out of
its burrow entirely, and moving around a bit. Maybe it was looking for
a better spot to moult? Or maybe because the room temperature exceeded
30°C (86°F) now and then?
In the above photo you can see the silk the tarantula has spun to
close off the entry to its burrow.
If all goes well I expect to be able to collect an exuviae, the cast
off exoskeleton, tomorrow, which can be used to determine the sex of
the tarantula which I don't know at this time of writing. I hope
female as females live much longer compared to males.
How does SQLite work? Part 1: pages!
I wanted to hack on SQLite, because I’ve
used it before, it requires no configuration or separate server
process, I’d been told that its source code is well-written and
approachable, and all the data is stored in one file. Perfect!
JSON is important, damn near everything that we do as programmers or
operators involves JSON at some point. JSON decoding is expensive,
if your product talks JSON then performance of marshalling data in
and out of JSON is important. This is a talk about designing an
efficient replacement for encoding/json.Decoder.
Sometimes it's necessary to split existing data into several classes
in order to predict new, unseen data. This problem is called
and one of the algorithms which can be used to learn those classes
from data is called Logistic Regression.
Pytorch is a pretty intuitive tensor library which can be used for
creating neural networks. There are many features in the framework,
and core ideas that should be understood before one can use the
The original tutorial by
provides a very good introduction that guides the users along
different concepts, explaining the different abstraction used in the
framework. It was a pretty involved read, and assumes some knowledge
on neural networks before everything on the page makes sense. So
here, we will be filling in some of these gaps.
In Python, metaclass is one of the few tools that enables you to
inject metaprogramming capabilities into your code. The term
metaprogramming refers to the potential for a program to manipulate
itself in a self referential manner. However, messing with
metaclasses is often considered an arcane art that’s beyond the
grasp of the proletariats.
Before I went to the bed I checked on the Brachypelma smithi I keep
and found it already out of its molt but still upside down. The
molting process had started
yesterday in the
About 10 hours later I took another photo of this specimen. It was now
right side up and moved when I opened the plastic container I keep it in.
In the afternoon I decided to determine the sex of this specimen. I
made the molt slightly wet and let it rest for a while; a moist exuviae
is much easier to manipulate. In order to take a good photo of the
spermathecae, if present, I put the exuviae on a piece of paper and
shone a light underneath the paper.
I used the macro lens I bought the 17th of June
2020, but with the LED
ring light off, to take the above photo which is a 1:1 crop with some
post processing in Pixelmator Version 3.9
Classic. The above photo clearly shows
the spermathecae, which means that this specimen is female.
Announcing Perl 7
Perl 7.0 is going to be v5.32 but with different, saner, more modern
defaults. You won’t have to enable most of the things you are
already doing because they are enabled for you. The major version
jump sets the boundary between how we have been doing things and
what we can do in the future.
Unknown to many of us, under the hood emacs was designed as a
client/server architecture; which means, Emacs core runs as a daemon
and you attach clients to it. Normally, we run both when we type
emacs, but the execution of both the client and the server is
transparent to the user. Before you attempt to do something fancy,
this architecture is somewhat limited to localhost (1), which means
that you can’t quite “remote into” an emacs running on a different
host. In a world where we have
mosh, and other multiplexers and mobile
connectivity technologies, there may not seem like there’s much room
for running emacs as a server, but we will see some advantages to
Tolkien saw a gap in England’s pre-history. There is English
folklore. However, this tends to be local and on a rather small
scale. There are Hengist and
legendary first Anglo-Saxons to lead an expedition to our shores,
but nothing with the grandeur and drama of the sagas mentioned
above. Tolkien planned to fill in the gaps before Hengist and Horsa
with a highly-developed imaginary world that harked back to a time
of elves and fairies.
Sometimes, you can have too much of a good thing. That’s certainly
true with Git
well-known software development workflow that offers several options
but can bog down users.
We developed GitLab Flow as the solution to eliminate messy
complexity and streamline the development process. GitLab
issue tracking to the Git workflow, simplifying the process and
removing confusion. The problem with Git flow
This PEP proposes adding pattern matching statements to Python in
order to create more expressive ways of handling structured
heterogeneous data. The authors take a holistic approach, providing
both static and runtime specifications.
In the evening, around 9:30 PM, I noticed that the Brachypelma
smithi I keep since the 7th of
had turned itself upside down. This means that it's going in ecdysis;
the shedding of its old exoskeleton.
It's important to not disturb the spider during this process, which
is often mistaken for dying by people new to keeping
tarantulas. Moverover, after the process one has to wait at least 7
days before feeding the spider; its exoskeleton including the fangs
have to harden out.
The End of OS X
What is striking about macOS 11.0 is the degree to which is feels
more like a son of iOS than the sibling that Mac OS X was:
macOS 11.0 runs on ARM, just like iOS; in fact the Developer
Transition Kit that Apple is making available to developers has
the same A12Z chip as the iPad Pro.
macOS 11.0 has a user interface overhaul that not only appears to
be heavily inspired by iOS, but also seems geared for touch.
macOS 11.0 attempts to acquire developers not primarily by being
open and good, but by being easy and good enough.
Ever since optional static typing was added to Python 3.5+, the
question of using type annotations keeps creeping back everywhere I
work. Some see them as a step forward for the Future of Python™, but
to me and many others it's a step back for what coding with Python
fundamentally is. I've been in a number of debates over type
annotations at work and so decided to compile some of the recurring
points of discussion here.
It's a bloody business, overthrowing a king. Now, amid the chaos, a
whispered rumour is spreading. A rumour about a broken promise,
omens of death and the gods returning to walk the earth.
No one really believes these whispers.
Perhaps they should.
In the evening I started in Promise of
book 1 in the Powder Mage trilogy by Brian McClellan.
A Conspiracy of Bones
Just after 1:30 AM I finished A Conspiracy of
A Temperance Brennan Novel Book 19, by Kathy Reichs. While I did miss
the lab work by Brennan a lot, I still consider it a good read.
An Overlooked Molt
After feeding the Hapalopus sp. Colombia "large", a dwarf tarantula
sling I keep, I suddenly noticed a molt attached to the underside of
the piece of cork bark the spider hides under.
I already suspected this little tarantula had molted when writing a
blog entry the 18th of
June which I linked to
a post written the 18th of
May. Each post shows the
Hapalopus sp. with a mealworm, but the tarantula looks smaller and
less colorfull in the older post.
And just now I had found proof that it had indeed molted somewhere
between those two dates.
Giving water to a Caribena versicolor
In the afternoon I used a dosing syringe to add some water to a small
terrarium in which I keep a Caribena versicolor sling. I moistened a
part of the substrate furthest away from the cork bark the little
spider resides most of the time and also put a few droplets on the
The spider walked around while I was doing this until it encountered a
droplet. Then it started to drink. I got my iPhone 5 ready; attached a
macro lens and a LED ring light which I had bought the
June. But when I moved
the phone close I bumped against the enclosure and scared the
tarantula away from the water droplet, hence the above photo of the
spider next to the droplet.
Browsing through the book it turned out to be fantastic; wonderful
photos and explanatory text. I can't wait to read this book. Based on
the photos alone highly recommended if you are interested in our eight