What I Learned Today

Last night, I sat down with a friend who instructed me in some basic crochet skills. While watching “Brokedown Palace” (somewhat bizarre movie, thought-provoking but… weird), I learned:

Chain: basic stitch, somewhat akin to casting on in knitting; just make a slip knot and iteratively pull a new loop of yarn through the one on your needle. Unlike knitting, there is only one stitch on the needle/hook at any given time.

Single crochet: insert hook through the top of the next stitch, wrap the yarn around it, pull it through to yield two stitches on the hook. Wrap the yarn once more and pull that through both stitches, leaving only one on the hook, and you’re reading to go again.

Double crochet: wrap the yarn around the hook, then insert it into the next stitch as to do a single crochet. Wrap the yarn again and pull it through to yield three stitches on the hook. Wrap the yarn again and pull it through the first two of those stitches, then wrap it again and pull it through the remaining two to leave one stitch.

Double crochet results in a lacier, more open stitch (and a wider fabric, at least in what I produced) than single crochet. I also observed that unlike knitting, crocheting appears to produce a symmetric fabric — there was no obvious “right” or “wrong” side. When you reach the end of a row, you just turn around and do the same thing back the way you came. Handy!

I’m pleased to augment my knitting skillz with some crochet know-how, since this opens up new territory in terms of adding decorative edges or hems or frills to items you knit. By the end of the movie, I had crocheted enough to produce a headband, which I wore home (to the disappointment of my friend’s one-year-old, who had it on and kept saying “Mir! Mir!” because she wanted to admire herself. :) ).

My Master’s degree research seeks to analyze rock samples to determine whether the structures therein might have been created by life. I’ve looked at various information theoretic approaches to analyzing digital images of samples, and currently I’m testing some texture characterization algorithms to see if they might be useful. It turns out that while there is a lot of existing work debating whether a given rock sample (e.g., stromatolite) was the result of bacterial life or abiotic chemical processes, few people have actually tested biogenic (“created by life”) and abiotic samples side-by-side. One challenge is that stromatolites take a really long time to grow, so it’s not exactly a weekend project.

However, I’ve gotten involved with the USC microbiology lab, and due to the generous assistance of a couple of graduate students, we’re going to do exactly that, but with simple organisms and reactions rather than trying to grow an entire stromatolite. The abiotic samples have already been grown and imaged, and now we’re working on the biogenic ones. To learn how to do this, I reported to the microbiology lab this afternoon and spent two hours trying to absorb a whirlwind of new terminology, procedures, and concepts. Here’s what we did:

1. Create some “growth medium”. This involves mixing a powder with distilled water to create a “broth” in which bacteria will like to grow. We used “marine broth 2216” and water from the Nanopure Filtration System. We then stirred the mixture, which these days does not mean sticking a rod in and swirling it around manually. No, you put the glass jar on a “stirrer”, which when turned on moves its platform in gentle horizontal circles. That wasn’t enough to get the powder to completely dissolve, so we threw in a magnet (!) which is affected by the stirrer and spins around independently, thoroughly mixing the solution. Very cool.
2. Sterilize the medium. Here we screwed the lid on the glass jar, stuck “autoclave tape” on it, and then put it in the autoclave. The autoclave is effectively a pressurized oven that (in this case) warms its contents up to a toasty 121 C. (It’s pressurized so that the fluid can be pushed above its boiling point — clever!) It stays at 121 C for 15 minutes and then cools down. The autoclave tape has bands that go black after it’s been cooked, so that you know whether the contents are sterile or not.
3. Inoculate the medium with bacteria. We’re using a Mn-oxidizing bacteria (an erythrobacter) that is known to generate interesting structures. We pulled some out of cold storage (-80 C!) and pipetted it into the growth medium on a “clean bench”. The clean bench has a constant flow of air coming out to help minimize the chance of you contaminating your own samples. Again, instead of old-time manual pipettes, we had the aid of a “pipet aid”, which is a hand-held device that creates a tiny vacuum and with a push of a button can suck up or release precise quantities of fluid.

We then put everything away (the inoculated samples in a dark closet), and I’ll go back next week to work on the next steps. It turns out that I will also have to take “lab safety” training (certainly not a bad idea) that is spread out over three days, at 2.5 hours each day (!). This is inconvenient, to put it mildly, when one has a day job. :) But regardless, I definitely learned something new today. And there’s more to come.

I’ve gotten used to the idea that socks are knitted in the round because of their tube-like shape; knitting in the round means no seams to do up at the end. However, I recently discovered that argyle socks are an exception: the leg (and sometimes part of the instep) is knitted *flat*, and then a seam is sewn up the back of the sock, and then knitting proceeds in the round for the foot of the sock. I’ve become interested in argyles because I haven’t yet attempted any “colorwork” aside from horizontal stripes (which don’t require any special technique) and I’d like to try something more complicated. I wondered, then, why the instructions would be different for these socks. As explained by Moth Heaven (her sock (leg) is shown at right; the ribbing is at the bottom and the leg proceeds upwards):

If you knit across a row in intarsia, for example — dropping the pink to pick up the green, when you come back around again on the next row, the end of the pink yarn will be all the way over on the other side of the diamond. That is why intarsia is knit flat.

Again, I haven’t attempted any colorwork yet, so “intarsia” is still a vague concept (one I hope to clarify soon), but even so this explanation made sense to me. I love explanations! Knitting instructions, like cooking recipes, tend to be very prescriptive (do this, do that), without stopping to explain why. No doubt this is because there’s a lot of domain knowledge you pick up by experience, and the typical pattern or recipe writer doesn’t want to take the time to spell out the reasons for each step, but it sure helps you learn faster, have more confidence in what you’re doing, and gain the ability to adapt patterns without making a mess.

I also recommend the excellent step-by-step guide to argyles from the same site. I haven’t actually used it yet, but an argyle sock is rising to the top of my to-knit list. (She also appears to be using the magic loop technique — cool.)

Recently, I received a pingback on one of my posts at this site. This inspired me to find out how trackbacks and pingbacks work. The main question was: how does a site know about posts that are made elsewhere that link back to a local post?

As usual, wikipedia came in handy, complete with a table comparing refbacks, trackbacks, and linkbacks. Here’s my summary:

A trackback occurs when server A notifies server B that A contains a reference to content on B. B can then publish a link back to A’s content (often with a small bit of context); this context-link is often referred to as the “trackback”. Since this activity involves communication between servers, it only works for blogging software that is trackback-enabled. Often the person writing weblog A must also use a special “trackback URL” (specified by B) when referring to the content on B — and not just in the content of their post, but in a separate “trackback” field (e.g., for WordPress).

Note that a trackback doesn’t actually require that A had a legitimate post that pointed to B. Anyone can send the web request to B suggesting a site to link back to. This seems to have quickly become another route for incoming spam on various weblogs, so a new form with additional verification has arisen.

A pingback is a trackback in which server B checks A for an actual link back to B’s content. Again, both A and B must actively support pingbacks for this to work. An advantage is that no special URLs are needed; when A links to B, there is an automatic notification to B (and B can confirm the legitimacy of A’s pingback).

Sounds pretty good, doesn’t it? Well, the pingback I received was a bit perplexing. It wasn’t a pingback in the sense of someone writing a post about something I wrote. But it wasn’t (quite) spam, either. As far as I can tell, it linked to a kind of automated blog that links verbatim to posts on a variety of subjects (probably specified by keyword). I was unable to determine what the purpose of the site was. I’ve deleted the pingback. But it gets a small kudos anyway, for inspiring me to find out something new.

Lately, I’ve been engaged in a duel with my inbox. I’m trying to get it down as low as possible. It’s trying to expand without limit. We usually manage an uneasy balance that involves me going through spurts of filing and deleting and it going, “You’ve got mail!” (No, it’s not audible. Email is distracting enough without an interrupting beep.)

At any rate, I realized one day that I didn’t even have a clear idea of the true magnitude of the problem. How much email was I receiving each day? And what kinds of messages were they?

I decided to track incoming email for a week. The graphic at right (click to enlarge) shows the fractional breakdowns between spam and non-spam, and then a further breakdown of the non-spam in terms of what I did with it (not always accomplished on the day it arrived).

Here’s what I learned:

• I receive an average of 88.67 messages per day: 38.67 are spam and 50 are non-spam.
• The spam filter in my Mac OS X Mail.app is really, really good. Not shown in this graphic is the fact that I also tracked how many spam messages I had to manually mark. This ended up being 4 messages over six days, or just 0.67 messages per day. I’m impressed!
• The most common action I take is to delete messages (19.83 per day). This suggests an obvious means for reducing the number of messages I receive: get off of mailing lists. Unfortunately, there’s only one I’m subscribed to, so this won’t help a lot. It was interesting to discover how much of my email serves only an informative purpose, requiring neither an answer nor to be filed.
• I send a short answer to 13.33 messages per day, and I file (without answering) 11.5 additional messages. If I answered it, I probably filed it too. Therefore my mail files grow by at least 38.13 messages per day, because I usually file my response as well. It’s actually more, because I send a lot of messages that aren’t replies to incoming messages (thereby adding to someone else’s email inbox problem. Go me!).
• Most worrying, perhaps, is the “no action” category (5 messages per day). These are net increases in the size of my inbox. And that’s after reducing the number when I deal with that day’s messages on subsequent days, too. Sometimes I conclude my day with 15 or 20 “no action” emails, which just have to be processed later. This is where I’d like to really take corrective action. But if I file email prematurely (before I do whatever needs doing with respect to its contents), then I forget about it (and the task doesn’t get done). I’ve tried moving these items to a separate (small) “Action” folder, but then I forget about that folder. Any suggestions on how to deal with this?

Overall, this was an interesting exercise, and now I have a better idea of how much email I need to deal with on a daily basis, and where my energies need to be focused. I got to claim a minor victory today: for the first time in months (maybe even years), my work inbox got below 100 messages. Yay!