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The toxic sheep collar for control of sheep-killing coyotes: A progress report
The toxic sheep collar is the most selective method known for killing coyotes that prey on domestic sheep. The concept dates back to the early 1900's and has been studied at the Denver Wildlife Research Center (DWRC) since 1974. Field tests with sodium cyanide (NaCN) in 1975 were unsuccessful due to repellent properties of the toxicant and to the apparent reluctance of coyotes to attack tethered lambs wearing bulky collars. Coyotes attacked one or more tethered, collared lambs in 7 of the 19 test pastures. In all, 14 collared lambs were attacked. Eight of the collars were punctured but no dead coyotes were recovered. A smaller collar containing diphacinone was field tested in 1976. The diphacinone-filled collars were readily accepted by coyotes and lethal to them, but the slow action (5-16 days between dosing and death) of diphacinone made it difficult to assess the effectiveness of these collars under field conditions. Target flocks containing 1 to 12 collared lambs plus uncollared ewes were placed in 15 fenced pastures from which the larger ranch flocks had been removed after repeated coyote predation. One or more collared lambs were attacked in 11 of the 15 tests. An unknown number of coyotes were killed, and in most tests the subsequent incidence of predation was lower than that before the test. Captive coyotes continued to kill sheep for 4 or 5 days after they received a lethal dose of diphacinone; therefore a faster-acting toxicant is needed. This research has shown that problem coyotes can be killed with toxic collars, but further studies are needed to determine the feasibility of this approach compared with traditional means of control. In most tests to date the frequency of coyote predation has been too low and too irregular to permit effective use of the collar; target flocks were in the field for an average of 10 days before being attacked. The known disadvantages of the method include the need to sacrifice live lambs, the human hazards associated with the use of toxicants under field conditions, and the costs of managing target flocks and other sheep in the problem areas
Pair Events in Superluminal Optics
When an object moves faster than emissions it creates, it may appear at two
positions simultaneously. The appearance or disappearance of this bifurcation
is referred to as a pair event. Inherently convolved with superluminal motion,
pair events have no subluminal counterparts. Common examples of superluminal
motions that exhibit pair events include Cherenkov radiation, sonic booms,
illumination fronts from variable light sources, and rotating beams. The
minimally simple case of pair events from a single massive object is explored
here: uniform linear motion. A pair event is perceived when the radial
component of the object's speed toward the observer drops from superluminal to
subluminal. Emission from the pair creation event will reach the observer
before emission from either of the two images created. Potentially observable
image pair events are described for sonic booms and Cherenkov light. To date,
no detection of discrete images following a projectile pair event have ever
been reported, and so the pair event nature of sonic booms and Cherenkov
radiation, for example, remains unconfirmed. Recent advances in modern
technology have made such pair event tracking feasible. If measured, pair
events could provide important information about object distance and history.Comment: 13 pages, 3 figures. in press: Annalen der Physi
Reply to Itin, Obukhov and Hehl paper "An Electric Charge has no Screw Sense - A Comment on the Twist-Free Formulation of Electrodynamics by da Rocha & Rodrigues"
In this note we briefly comment a paper by Itin, Obukhov and Hehl criticising
our previous paper. We show that all remarks by our critics are ill conceived
or irrelevant to our approach and moreover we provide some pertinent new
comments to their critical paper, with the aim to clarify even more our view on
the subject.Comment: This paper is a reply to arXiv:0911.5175 [physics.class-ph] which
made some criticisms on our paper "Pair and Impar, Even and Odd Form Fields
and Electromagnetism" arXiv:0811.1713 [math-ph] to appear in Annalen der
Physik. A short version of our reply will also appear in Annalen de Physi
The Hidden Subgroup Problem and Eigenvalue Estimation on a Quantum Computer
A quantum computer can efficiently find the order of an element in a group,
factors of composite integers, discrete logarithms, stabilisers in Abelian
groups, and `hidden' or `unknown' subgroups of Abelian groups. It is already
known how to phrase the first four problems as the estimation of eigenvalues of
certain unitary operators. Here we show how the solution to the more general
Abelian `hidden subgroup problem' can also be described and analysed as such.
We then point out how certain instances of these problems can be solved with
only one control qubit, or `flying qubits', instead of entire registers of
control qubits.Comment: 16 pages, 3 figures, LaTeX2e, to appear in Proceedings of the 1st
NASA International Conference on Quantum Computing and Quantum Communication
(Springer-Verlag
Effects of Acoustic Coupling Layer Electrical Conducitivity on Pulsed Electroacoustic Measurements
The spatial resolution of Pulsed Electroacoustic (PEA) measurements can be limited by the acoustic thickness of the coupling material coupling the sample to the detector assembly. Our investigations studied the effect of adhesive material and thickness to optimize the quality of the PEA signal
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