Random Ramblings to 17 November 2009

Acidosis
An increase in the acidity (or a decrease in the pH) of blood. The eventual state of highly acidic blood is referred to as acidaemia. The pH of blood must be kept near 7.4 (slightly basic) or the body will not be able to function properly. One type of acidosis occurs when carbon dioxide (CO₂) is not released through the lungs fast enough, causing a buildup of carbonic acid (H₂CO₃). Another type of acidosis (lactic acidosis) occurs from excessive anaerobic respiration, where instead of using oxygen to break down sugar to release energy, the body instead breaks the sugar down into lactic acid. The lactic acid itself does not cause the acidity, but rather the respiration process. This commonly happens when sleeping on an arm, which becomes numb and experiences a pins-and-needles sensation when blood circulation is finally restored.

Latus rectum
In geometry, a chord of a curve is a straight line which is bounded by two points on the curve. A focal chord of a curve that is a conic section is a chord which crosses through one of the conic section's foci. The latus rectum of the conic section is the focal chord which runs parallel to the directrices. It translates to "straight side" from Latin.

The latus rectum (in blue) of a parabola (in red).

Moral hazard
In economics, the human tendency where a person behaves a certain way when exposed to risk (usually cautious), but behaves differently when someone else protects them from it (usually more complacent). It happens because that someone else bears some of the burden of the risk, so said person can afford to take more risk. This commonly occurs in relation to insurance, where the person may act more carelessly after acquiring it. This explains why insurance policies tend to include an excess (since an excess forces the insured to bear some of the burden of an insurance payout). Another, WoW-related example can be found here.

Repetitive strain injury (RSI)
A health condition where a joint becomes painful from its misuse or overuse. It is commonly applied to pain at the wrist arising from prolonged computer use. Actions contributing to this form of RSI include typing and moving the mouse by bending sideways at the wrist, especially when the wrist is bent downwards as well. This can be mitigated by keeping the arm straight across the wrist (a wrist rest may help) and moving the mouse with a full-arm motion.

Satellite Internet connection
An Internet connection that involves connecting to a satellite orbiting the Earth. A parabolic reflector (satellite dish) is needed to sufficiently boost the signal between the modem and satellite. In a one-way configuration, there is no uplink to the satellite, which must instead be made through dialup. While satellite Internet taps into the high bandwidth of the Internet backbone, it is also notorious for its high latency, which can be around 500ms per hop.

A satellite Internet connection regime.

Working capital
The liquidity of a business is its ability to pay its debts as they fall due (its current liabilities), presumably using its current assets (cash, inventory and receivables). Its working capital is the amount of current assets left over after paying its current liabilities. That is, Working capital = Current assets - Current liabilities. While low working capital increases liquidity risk for the business, a high working capital can point to inefficiencies in the business. A high level of inventory increases storage costs, while a high level of receivables increases costs from disposing of bad debts, and a high level of idle cash imposes an opportunity cost (they could have been investing that cash to earn income).