A brief gallivant about the marketplace of ideas.

Category: Reference

Cat litter : Do(-doo)s and don’ts


What follows are generally recommended practices. What works best will depend on the specifics of your cat(s).

  • If you have n cats, then have n + 1 litter boxes [3,4], distributed throughout the living space.
  • Clean the litter box by scooping out urine and feces at least every other day [1,2,3,4].
  • 3 cm (2 in) of litter is sufficient [3]. Beyond this, the cat may kick excess litter onto the floor [4].
  • Completely empty and clean (with mild detergent [3] or baking soda [4]) the litter box anywhere from once a week [4] to a few times a year [1] (and everything in between [2,3]).
  • Replace plastic litter boxes once a year [2], or when they look worn [4].

Feline Urethral Obstruction

For a discussion of FUO, read this post [6].


  1. How often do I really need to clean my cat’s litter box?“, by Dr. Justine A. Lee, DVM (Pet Health Network, 2015-04-21).
  2. Cleaning the litter box: how often is best?“, by Dr. Stephanie Janeczko, DVM (Pet Finder, ????).
  3. Preventing litter box problems” (Humane Society, ????).
  4. How often should I change my cat’s litter?“, by Ameera Mills (Animal Wised, 2018-06-03).
  5. What are the dangers of a dirty cat litter box?“, by Laura Agadoni (The Nest, ????).
  6. Help…my cat can’t pee! Feline urethral obstruction : be aware“, by Dr. Jason Nicholas, DVM (2012-01-12).

Glycogen and athletics

Executive Summary

Glycogen, the sugar stored your body, is a primary fuel for athletes. Glycogen stores are replenished by consuming carbohydrates. Endurance athletes should have high-carb diets. Intricate carb-loading strategies on race week are not worth the risks (e.g., fatigue, injury).


The body has three primary sources of fuel: carbohydrate (carb), fat, and protein. (More precisely, the body uses these substrates to produce energy in the form of ATP.) Fat yields more energy per gram (9 calories per gram (cal/g), versus 4 cal/g for carb and protein [4]), but carbohydrate is easier to burn. Carb is burned at all intensities of exercise [1]. As the intensity of exercise increases (above about 50% VO2 max), so does the carb-to-fat ratio in energy production [1].

Animals (including humans) store carb in the form of glycogen, in skeletal muscle (80%), the liver (14%), and the blood (6%) [1]. The human body can store about 400 – 500 grams of glycogen [1]. The body burns carb at a rate of approximately 1 – 2 grams per minute (g/min) at low-intensity exercise and 2 – 3 g/min at higher-intensity exercise [1]. At race intensity, the human body exhausts its glycogen supply after about 2 hours [1]. For marathon runners, this limit is related to the saying that the race is “half over at twenty miles” [2]

In general, athletes should consume a high-carb diet [3]. During competition, recommendations for carbohydrate consumption range from 30 – 60 grams per hour (g/hr) to 80 – 100 g/hr [1]. Such short-term, high-carb intake requires a mix of absorption rates and glycemic indices [1]. Various race-week diets have been proposed to prime the body to store more glycogen. These diets have been associated with higher rates of fatigue and injury; these risks may outweigh any benefits [3].

Insufficient glycogen is associated with fatigue and decreased athletic performance [1,3]. It may also elicit chronic overtraining, as follows: At low glycogen levels, the body switches to using more protein for energy production, and it can actually destroy existing muscle to produce protein for this purpose. The resulting muscle damage “interferes with glycogen [synthesis and storage]” [1], thus decreasing the body’s energy supplies and making future muscle destruction more likely. One athletic doctor cites this as “probably the number one cause of overtraining in athletes” [1].


  1. The importance of carbohydrates and glycogen for athletes“, by Iñigo San Millán (Training Peaks, 2013-01-17). A thorough article on glycogen vis-à-vis endurance athletes.
  2. The science of ‘bonking’ and glycogen depletion“, by John Davis (Runners Connect, 2011?). This article briefly discusses the nutritional basics before examining glycogen-depleted training at length.
  3. Optimizing glycogen storage“, by Kathleen Deegan (Sacramento Running Association, ????). The takeaway from this article seems to be that stressing about diet the week before an event can be self-defeating. Just eat a generally high-carb diet, and replenish carbs during the event.
  4. Carbohydrates, proteins, and fats“, by Adrienne Youdim et al. (Merck Manual, ????).

Cybersecurity : Home Wi-Fi

Wifi Security

With due respect to Allen Iverson, I know cyber security is important…but we ain’t talkin’ about corporate servers! We talkin’ about home networks! If someone hacks your home network, their only reward is use of your internet, right?

Wrong. A forum [1] related to the comic xkcd gives us some motivation for securing our home’s wireless local area network (WLAN). (N.B. The expertise of the posters on this forum — listed in [square brackets] after their point, and linked to their post — is unknown (to me). My expertise is limited. Those caveats aside, the cited postings sound legitimate, and they check out against what validation I can currently do.)

  • Waste bandwidth [EvanED]. E.g., the hackers illegally download a bunch of videos, which slows down your internet connection. Hackers might not be so nice as to restrict themselves to illegal downloads.
  • Engage in illicit activity (think: your subsequent liability). [EvanED]. The post gives a good example.
  • Access shared files [EvanED].
  • Read your traffic [Tub]. If your traffic is not encrypted, you’re sharing that activity with your hackers. If your traffic is encrypted, that gives you a secondary layer of defence, but it’s not impervious. Read on.
  • Manipulate your traffic [Tub]. In particular, if the hackers (instead of your router) can assign your device its IP address, then they could rerout that device’s traffic to the hackers’ machine. (N.B. I don’t know how feasible such an attack is, i.e. for hackers to run a custom DHCP server on a WLAN.)
  • Install malware on your router [3]. The cited article claims that, if your router becomes infected, then all devices that connect to it become vulnerable.
  • Access devices connected to your network [Tub, korona]. This type of attack exploits security vulnerabilities in the software running on your devices.

OK, OK, OK, so maybe we do care about securing our home network. How do we do it? Following are several steps we can take, gleaned from various articles online. The articles (cited after each point, and listed below) contain more suggestions and discussion. Check them out when you have time.

  • Change the manufacturer-set name and password of your wifi [2,3,4,5,6]. Choose a network name that doesn’t reveal your router’s manufacturer or your location. Choose a password that’s (very) strong. The password strength is especially important for the network administrator function.
  • Keep your router’s firmware/software up to date [2,3,4]. As noted in several articles [3,4], your router may not send you regular notifications and reminders. Fortunately, Google calendar (or an analogous service) will — just set it up.
  • Keep your router hardware up to date [3]. Technology ages. Fast. Older hardware is less likely to receive software updates and (therefore?) perhaps more susceptible to hacking.
  • Enable encryption [2,4].
  • Kill WPS [4,5].
  • One site [2] recommends turning off DHCP functionality. This appears neither important nor prudent [7].


  1. Why is a good wifi password necessary?” (, 2014).
  2. How to enhance your home wireless network security“, by Ioana Rijnetu (Heimdal Security, 2018-01-18).
  3. Your wi-fi security is probably weak. Here’s how to fix that.“, by Brian X. Chen (NY Times, 2018-06-13).
  4. Your router’s security stinks: here’s how to fix it“, by Paul Wagenseil (Tom’s Guide, 2018-05-29).
  5. How strong does your wifi password need to be?” (Linkd Home, 2017-10-10).
  6. Understanding the most important wifi settings” (Net Spot App, ????).
  7. Does disabling DHCP on your router really help your security?“, by Miguel Leiva-Gomez (Make Tech Easier, 2014-05-12).

Router positioning

  1. Where to put your router for the best possible home wi-fi“, by April Glaser (Wired, 2016-03-01).
  2. The best place for your wireless router“, by Bradley Mitchell (Lifewire, 2018-05-17).
  3. Where to place your router to get the absolute best wifi connection“, by Sara Boboltz (Huffington Post, 2015-03-27).


Selected references on flashlights:

  1. Best front and rear road bike lights reviewed 2018” (Cycling Weekly, 2018-01-04).
  2. 20 best tactical flashlights“, by Adam Smith (Gear Moose, ????).

Sunglasses (for health, not fashion)

  1. The most important health feature of sunglasses appears to be protection against ultraviolet (UV) light [1,2]. Not all sunglasses offer this protection.
    1. Many articles distinguish UVA and UVB [1,2,3,4] and mention that protection against both is important.
    2. Wearing sunglasses without UV protection causes your pupils to dilate, allowing more light (and hence UV light) to enter your eye [3,4,5].
  2. Polarization does not offer additional protection from UV light [6]. Polarization’s main function appears to be to reduce glare, i.e. to sharpen vision. (Fun fact: Polarized lenses were created by scientists at NASA’s Jet Propulsion Laboratory! [7])
  3. For UV protection, one article claims that “lens color and darkness don’t matter” [5], another claims that “[d]ark tinted glasses block more light than regular sunglasses” [8], and the American Cancer Society claims that it “depends on the type of tinting” [9]. Reddit features a post on their “askscience” channel that claims “[v]irtually all plastics cut off [UV light] hard below 300nm” [10]. However, it appears that being simply plastic does not guarantee UV protection.
  4. Certification of UV-blocking ability appears to be poorly regulated [1,3,5]. An article from 2016 recommends looking for “[h]ard numbers”, like “99% UV absorption”, on sunglasses, claiming that these are the only claims that the US Food and Drug Administration requires to be true [5].
  5. A bonus sciency article [11].

Gun violence


  1. Guns in the US: The statistics behind the violence” (BBC News). See the chart on homicide rate.
  2. What explains U.S. mass shootings? International comparisons suggest an answer“, by Max Fisher & Josh Keller (NY Times, 2017-11-07).
  3. Gun control: What can America learn from Britain?“, by Patrick Worrall (Channel 4, 2013-01-16). A reminder that statistics are summaries; dig to know what goes into them.
  4. America’s gun culture in 10 charts” (BBC News, 2018-03-21).

Read — 2018/02/11

Today’s selection of articles:

  1. Tim Harford’s guide to statistics in a misleading age“, by Tim Harford (Financial Times).
  2. The book every programmer should read“, by Vinicius Brasil (Hacker Noon). Spoiler alert: The book is “Clean code“, by Robert C. Martin.
  3. How does Tor *really* work?“, by Brandon Skerritt (Hacker Noon). Even if someone else reads the white paper, it doesn’t mean you don’t have to. Though it also doesn’t mean you can’t be appreciative when they do.

Super Bowl LII : Football primer

A selection of references explaining American football:

  1. A beginner’s guide to American football” (NFL). A 1:18 YouTube video explaining the basic objectives.
  2. Rule book: A beginner’s guide to football” (NFL). A dry explanation of the rules.
  3. Super Bowl 51: A beginner’s guide to American football” (BBC). Written for last year’s Super Bowl, this article makes the cut because it uses words like “pitch” (for “field”) and “defence” (for “defense”).

Read — 2017/12/22

Today’s selection of articles:

  1. The SEC’s crackdown on cryptocurrencies is about to get serious, former chairman says“, by Michael Sheetz (CNBC).

And a recipe for the holidays (I tried these, and attest that they are delightful!):

  1. Chewy ginger molasses cookies“, by Ali (Gimme Some Oven).

NYC Marathon (2017-11-05)

Today’s selection of articles:

  1. USA’s Shalane Flanagan, Kenya’s Geoffrey Kamworor, and Switzerland’s Marcel Hug and Manuela Schä win 2017 TCS New York City Marathon” (NYRR). Congratulations Shalane!
  2. New York City Marathon: elevation profile” (TCS NYC Marathon).
  3. Apple varieties of New York state” (NY Apple Country).