What's the difference between treadle and trendle?

Treadle

Definition:

(n.) The part of a foot lathe, or other machine, which is pressed or moved by the foot.
(n.) The chalaza of a bird's egg; the tread.

Example Sentences:

(1) Three coyotes were operantly conditioned to depress one of two foot treadles, left or right, depending on the condition of the stimulus light.
(2) Ashden Outstanding Achievement Award International Development Enterprises India (IDEI) - for a simple treadle pump that has lifted more than 750,000 farmers out of poverty.
(3) Groups of pigeons were trained to depress a treadle in the presence of a compound stimulus consisting of a tone and a red houselight (a) to avoid electric shock, or (b) to obtain grain.
(4) The facilitative effect was equal in four cases: (i) making no response (NR), (ii) finger abduction (FA), (iii) noninvolved muscle (NIM), and (iv) involved muscle during treadle pressing (IM).
(5) The effects of promazine on treadle pressing to postpone the presentation of electric shock were studied in three pigeons.
(6) In Experiment 2 eight pigeons learned a treadle-press response to avoid or escape shock on a signaled free-operant schedule.
(7) Rates of responding changed systematically across sessions for rats pressing levers and keys and for pigeons pressing treadles and pecking keys.
(8) After performance had stabilized, the degree to which each element controlled treadle pressing was determined.
(9) Selected doses of both promazine and chlorpromazine increased the rates of treadle pressing in all birds.
(10) Two experiments investigated free-operant avoidance responding with pigeons using a treadle-pressing response.
(11) The response-rate increases produced by promazine and chlorpromazine were due to increased conditional probabilities of treadle pressing both before and during the preshock stimulus.
(12) Effective doses of apomorphine caused dose-dependent decreases on treadle-pressing rates in all animals.
(13) Appropriate doses of amphetamine caused rate-increasing effects on key-pecking as well as treadle-pressing rates of all pigeons.
(14) Frame-by-frame analysis of videotape records of E21 rat fetuses revealed that tactile contact with the artificial nipple elicited mouthing, licking directed at the nipple, forelimb treadling, and grasping of the nipple.
(15) Pigeons were trained to depress and hold a foot treadle until a stimulus change occurred.
(16) Each treadle press postponed electric shock for 20 sec and presentation of a preshock stimulus for 14 sec.
(17) Key-pecking and treadle-pressing behavior were maintained in five pigeons by a mult.
(18) For example, Climate Care is helping to fund simple 'treadle' water pumps for farmers in India, to give them the freedom to irrigate their crops without relying on expensive, polluting diesel pumps.
(19) This will take over 2000 years to make the same carbon savings as the treadle pump project will make in a single year with the same investment.