Comentários do leitor

Things of Interest

por Cyril Packard (24-09-2024)


They are, but that’s not my point here. But my point would still hold. Inputs and outputs are in balance. Inputs and outputs, not colliding billiard balls. That’s why colliding billiard balls are a paradigmatic example of causality in philosophy. The example is predator-prey dynamics. Here’s an example. It’s a population ecology example, but not because population ecology is the only bit of ecology that’s about dynamical systems. But ecology is mostly not like billiards, or falling dominoes, or Rube Goldberg machines. The toy car is pushed into a line of dominoes, the last of which falls onto another toy car, which rolls down a ramp and runs into a ball, which rolls down another ramp… Your cue strikes the cue ball, causing it to roll into another ball, causing that ball to roll into the corner pocket. When once a man's given to it-as my poor aunt used to say-the devil's always tempting him with a ball, as he tempted Eve with an apple.



I had found my ghost and would have given worlds to have escaped from that dâk-bungalow. A ghost that would voluntarily hang about a dâk-bungalow would be mad of course; but so many men have died mad in dâk-bungalows, that there must be a fair percentage of lunatic ghosts. That person must don the witch hat, name the first kid's ingredient, then add his or her own ingredient before passing the hat. Trying to find unique OTC Billiards Custom Designer Merchandise that you can add text to, your personal name, Are you a member of the APA, TAP, BCA any pool league team looking for unique billiard art or designs that you can add text to, a members name, a team name? So don't hesitate, add the 7FT 4IN1 Convertible Pool Table-Premium Quality 2024 New to your home today and take your game room to the next level! So technically, pool is a billiards game with pockets.



I hope you get a chance to try the game and you enjoy it as much as I do. And once they get there, they might discover that they don't want to leave. I watch ESPN every chance I get. But you’re never going to find something that lets you redescribe predator-prey dynamics in terms of sequences of events, each causing the next. Today, we’re going to explain the differences and similarities of each. Like history, ecology is (mostly) not "just one damned thing after another." But it’s hard not to think of it that way, and to teach our students not to think of it that way. For concreteness, what is billiards let’s say it’s a limit cycle in the Rosenzweig-MacArthur model. And again for the sake of simplicity, let’s say it’s a constant environment and there’s no particular time at which organisms reproduce or die (e.g., there’s no "mating season"), so reproduction and mortality are always happening, albeit at per-capita and total rates that may vary over time as prey and predator abundances vary. Purely for the sake of simplicity (because it doesn’t affect my argument at all), let’s say it’s a closed, deterministic, well-mixed system with no population structure or evolution or anything like that, so we can describe the dynamics with just two coupled equations, one for prey dynamics and one for predator dynamics.



Two podiums using the skins from the HP costume trunks, I had these bad boys on TSR in the old days, but now I've placed them here for your downloading pleasure! Now I can hear some of you saying, ok, that’s true of the math we use to describe the world, but it’s not literally true of the real world. For instance, you can have a sequence of causal events in which the magnitude of the effect is nonlinearly related to the magnitude of the cause. At every instant in time, prey are being born, and prey are dying, and those two rates are precisely equal in magnitude but opposite in sign. And at every instant in time, predators are being born and predators are dying, and those two rates are precisely equal in magnitude but opposite in sign. Why do the predators and prey cycle? Predators convert consumed prey into new predators, and they die.