J. Gregory McDaniel

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The embryos of red-eyed treefrogs, Agalychnis callidryas, use vibrations transmitted through their arboreal egg clutch to cue escape hatching behavior when attacked by egg-eating snakes. Hatching early increases the risk of predation in the water, so embryos should avoid it unless they are in danger. We exposed egg clutches to intermittent vibrations with(More)
Incidental acoustic and vibrational cues generated by predators are a potential source of information for prey assessing risk. Substrate vibrations should be excited by most predators, and frequency, amplitude or temporal properties could allow prey to distinguish predator from benign-source vibrations. Red-eyed treefrog embryos detect egg predators using(More)
A method is presented for estimating the complex wave numbers and amplitudes of waves that propagate in damped structures, such as beams, plates, and shells. The analytical basis of the method is a wave field that approximates response measurements in an aperture where no excitations are applied. At each frequency, the method iteratively adjusts wave(More)
Surface waves are commonly used for vibration-based nondestructive testing for infrastructure. Spectral Analysis of Surface Waves (SASW) has been used to detect subsurface properties for geologic inspections. Recently, efforts were made to scale down these subsurface detection approaches to see how they perform on small-scale structures such as concrete(More)
A wave model is proposed for estimating damping loss factor as a function of frequency for a beam with arbitrary transient loading applied through the boundary conditions. In contrast to modal methods which provide measures of damping only at the modal frequencies of the test structure, the damping factor is determined over discrete, but regularly spaced,(More)
A variety of engineering structures consist of a homogeneous &&master structure'', such as a plate or shell, to which are attached multiple arrays of substructures, such as ribs or stringers. The goal of this work is to understand the e!ects of array impedance and spacing on energy #ow in the master structure. Such an understanding may ultimately lead to a(More)
Prey assessing risk may miss cues and fail to defend themselves, or respond unnecessarily to false alarms. Error rates can be ameliorated with more information, but sampling predator cues entails risk. Red-eyed treefrogs have arboreal eggs and aquatic tadpoles. The embryos use vibrations in snake attacks to cue behaviorally mediated premature hatching, and(More)
The causality condition is examined as a means of determining frequency-domain information about a submerged object from a partial knowledge of its acoustic reflection characteristics. A one-dimensional problem is considered in which an acoustic wave reflects from an object that is described by the impedance it presents to the fluid. Two new applications of(More)
This work presents a convenient and non-contact acoustic sensing approach for measuring ground vibration. This approach, which uses an instantaneous dynamic tire pressure sensor (DTPS), possesses the capability to replace the accelerometer or directional microphone currently being used for inspecting pavement conditions. By measuring dynamic pressure(More)
We have recorded (1+1) resonance-enhanced multiphoton ionization spectra of complexes formed between NO and the alkanes: CH(4), C(2)H(6), C(3)H(8), and n-C(4)H(10). The spectra correspond to the à ← X̃ transition, which is a NO-localized 3s ← 2pπ* transition. In line with previous work, the spectrum for NO-CH(4) has well-defined structure, but this is only(More)