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Little is known about the movements of most stream fishes, so fisheries managers often rely on natural history data from the literature to make management decisions. Observations of over 15 000 individuals from 37 species across 3 years were used to evaluate four aspects of the reliability of literature data for predicting the movement behaviour of stream fishes: (i) water temperature when fish enter streams; (ii) reasons for moving into the streams; (iii) stream residence times of migrants; and (iv) relative use of lake and stream habitats. Comparisons of our data for arrival times in the streams, water temperature at arrival, and time spent in the streams were highly correlated with literature data, whereas relative use of the lake was not. Further, our detailed data revealed two novel findings: (1) in many species juveniles were also moving into streams, even in those species where adults were clearly spawning in the streams; and (2) adult-sized individuals were moving into streams for nonreproductive purposes. Our results suggest that fishery managers can confidently use natural history information to gain general insights into the movement ecology of fishes, but should also recognize that this information remains incomplete in important ways. Les connaissances sur les deplacements de la plupart des poissons de cours d'eau sont tres limitees, de sorte que les gestionnaires des peches ont souvent recours a des donnees d'histoire naturelle tiree de la litterature pour eclairer leurs decisions de gestion. Des observations sur plus de 15 000 individus de 37 especes recueillies pendant 3 ans ont ete utilisees pour evaluer quatre aspects de la fiabilite des donnees tirees de la litterature pour ce qui est de predire le comportement de deplacement des poissons de cours d'eau, soit (i) la temperature de l'eau quand les poissons entrent dans les cours d'eau, (ii) les raisons qui les poussent a entrer dans les cours d'eau, (iii) les temps de sejour des migrants dans les cours d'eau et (iv) l'utilisation relative d'habitats de lac et de cours d'eau. Nos donnees sur les temps d'arrivee dans les cours d'eau, la temperature de l'eau a l'arrivee et le temps passe dans les cours d'eau sont fortement correlees aux donnees tirees de la litterature, ce qui n'est pas le cas pour les donnees sur l'utilisation relative de lacs. En outre, nos donnees detaillees revelent deux nouvelles constatations, soit que (1) pour de nombreuses especes, les juveniles entrent egalement dans les cours d'eau, meme chez les especes pour lesquelles il est clair que les adultes frayent dans les cours d'eau et (2) les individus de taille adulte entrent dans les cours d'eau a des fins autres que la reproduction. Nos resultats donnent a penser que les gestionnaires des peches peuvent se fier aux donnees sur l'histoire naturelle pour etablir une comprehension generale de l'ecologie des deplacements des poissons, mais qu'ils doivent egalement tenir compte du fait que ces renseignements demeurent incomplets a d'importants egards. [Traduit par la Redaction], Introduction Human impacts on the biosphere are pressing scientists to provide information and solutions to help conserve native biodiversity and ecosystem services (Palmer et al. 2004; Venter et al. 2006). [...]

A 3-D reference model for wideband multiple-input multiple-output (MIMO) mobile-to-mobile (M-to-M) channels is reviewed along with its corresponding first- and second-order channel statistics. To validate the reference model, an experimental MIMO M-to-M channel-sounding campaign was conducted for M-to-M vehicular communication with vehicles that travel along surface streets and expressways in a metropolitan area. To compare the first- and second-order channel statistics that were obtained from the reference model with those obtained from the empirical measurements, a new maximum-likelihood-based stochastic estimator is derived to extract the relevant model parameters from the measured data. The measured data is processed and compared with the analytical results. The close agreement between the analytically and empirically obtained channel statistics confirms the utility of the proposed reference model and the method for estimating the model parameters. Index Terms--Channel sounding, mobile-to-mobile (M-to-M) channels, parameter estimation, wideband channel model.

A dual-polarized radar system is utilized for non-contact sensing applications involving rotational motion. Polarization-centric methods are employed to sense and characterize responses from an electric motor with various bearing faults and to sense responses from a high-velocity fan. Conventional characterizations, such as power spectral densities and micro-Doppler responses, are compared with polarization-based statistical approaches such as polarization entropy and a newly proposed micro-Entropy approach inspired by the micro-Doppler approach. [ABSTRACT FROM AUTHOR]

The performance of multiple-input-multiple-output systems with optimum combining (OC) is studied in a Rayleigh fading environment with arbitrary-power cochannel interference and thermal noise. Based on the joint eigenvalue distributions of quadratic functions of complex Gaussian matrices, a closed-form expression for the exact distribution of the output signal-to-interference-plus-noise ratio (SINR) is derived. A closed-form expression for the exact moment-generating function (MGF) of the output SINR of single-input-multiple-output (SIMO) systems is also derived. From the exact MGF, the moments of the output SINR and the symbol error rate of various M-ary modulation schemes are obtained. We verify the accuracy of our analytical results with numerical examples. The new analytical framework provides a simple and accurate way to assess the effects of equal-and unequal-power cochannel interferers and thermal noise on the performance of OC. Index Terms--Adaptive antennas, cochannel interference, fading channels, multiple-input-multiple-output (MIMO) systems.

Abstract: We use matrix models incorporating uncertainty in values of life history traits and density-dependent survival to assess pest management strategies implemented by the Great Lakes Fishery Commission to control [...]

The performance of multiantenna receivers in cochannel interference is investigated for narrowband links in a non-line-of-sight mobile-to-mobile channel. Channel impairments include Doppler spread and angular spread originating from scatterers in the vicinity of both the transmitter and the receiver. The analysis employs a two-ring scattering model and compares the performance of a sectored system employing selection combining (SC) to the performance of adaptive arrays implemented with both omnidirectional antennas and sectored antennas. Performance is estimated for environments with cochannel interference and is measured in terms of output signal-to-interference-plus-noise ratio (SINR). An ensemble of random scattering realizations is utilized in the analysis to estimate the average output SINR. The results demonstrate the improved performance offered by adaptive arrays over sectored systems with SC. Configurations involving both SC and adaptive array processing were also evaluated and found to yield improvements over conventional adaptive array architectures. Index Terms--Adaptive array, cochannel interference, mobile communications.

Abstract: We removed 40%-70% of nearshore wood habitat from three lakes to test the link between habitat and productive capacity, specifically focusing on the provision of substrate for periphyton and [...]

Use of companding for peak-to-average-power ratio (PAPR) control is explored for a link involving a nonlinear transmit power amplifier with orthogonal frequency division multiplexing (OFDM). Specifically, the objective of the study was to determine if companding using u-law compression/expansion at the transmitter/receiver, respectively, provides end-to-end performance gains relative to a system without companding. We consider the use of companding to ameliorate the impact of nonlinearities in the transmit amplifier. In the absence of companding, transmitter operation near saturation raises the signal level at the receiver but, because of the nonlinearities in the amplifier response, also results in distortion that impacts overall link performance. As the transmit power is backed-off from saturation, amplifier distortion is reduced, but error components due to lower SNR at the receiver become more significant. When companding is introduced in the system, the system is able to operate closer to saturation without substantial transmit distortion. However, requisite expansion of the compressed signal at the receiver yields noise amplification which can counteract any of the performance gains that would otherwise accrue from the increased SNR at the receiver. At issue is whether or not operating conditions exist (e.g., backoff, SNR, amplifier linearity model, etc) for which companding enhances the end-to-end performance relative to the link performance without companding. System simulation models were employed using Rapp's nonlinear power amplification models, where average symbol distance errors were used as performance metrics. We found that companding can provide very modest performance gains in comparison to systems that do not employ companding. Performance trends were corroborated in a hardware testbed with an amplifier chain, where average bit error rates were experimentally determined. Index Terms--Amplifier distortion, communication system performance, companding.

Cooperation diversity schemes have been proposed for cellular networks that permit mobile stations to relay signals to a final destination, thereby increasing the network capacity and coverage. The mobile relays either decode and retransmit the received signal or simply amplify and forward (A & F) the signal. The overall channel from the source to the destination via the relay in A & F systems is 'double' Gaussian with properties quite different from a typical cellular channel. Since very little is known about A & F relay fading channels, this paper considers their statistical properties such as the envelope probability density function, autocorrelation, level crossing rate, and system performance characteristics like frequency of outages and average outage durations. We briefly discuss the simulation of these channels and verify our analysis by simulations. Index Terms--Ad hoc cellular networks, channel statistics, cooperation diversity, Rayleigh fading, relay channels.

Mobile-to-mobile channels find increasing applications in futuristic intelligent transport systems, ad hoc mobile wireless networks, and relay-based cellular networks. Their statistical properties are quite different from typical cellular radio channels, thereby requiring new methods for their simulation. This paper proposes a "double-ring" model to simulate the mobile-to-mobile local scattering environment, and develops sum-of-sinusoids (SoS)-based models for simulating such channels. The proposed models produce waveforms having desired statistical properties with good accuracy, and also remove some drawbacks of an existing model derived by using the discrete line spectrum simulation method. Index Terms--Fading channel simulator, mobile-to-mobile channels, Rayleigh fading, sum-of-sinusoids (SOS).

Several new "sum-of-sinusoids" models have recently been introduced for the simulation of Rayleigh fading channels. These models are statistical in nature implying that their simulation parameters such as the Doppler frequencies are random. They have been shown to accurately reproduce some of the desired statistical properties of the faded envelope such as the time autocorrelation and the level crossing rate. However, a comparative analysis of these models, hitherto scattered throughout the literature, is not available. This paper compares these models in terms of their complexity and performance. The performance assessment is based upon the variance of the time average statistical properties from their ideal ensemble averages. Index Terms--Channel models, fading channel simulator, Rayleigh fading, sum-of-sinusoids (SOS).

Author(s): Felipe A. Court; Diane L. Sherman; Thomas Pratt; Emer M. Garry; Richard R. Ribchester; David F. Cottrell; Susan M. Fleetwood-Walker; Peter J. Brophy (corresponding author) Nerve impulses are propagated [...]

The February 7, 1812, New Madrid, Missouri, earthquake (M [moment magnitude] 8) was the third and final large-magnitude event to rock the northern Mississippi Embayment during the winter of 1811-1812. Although ground shaking was so strong that it rang church bells, stopped clocks, buckled pavement, and rocked buildings up and down the eastern seaboard, little coseismic surface deformation exists today in the New Madrid area. The fault(s) that ruptured during this event have remained enigmatic. We have integrated geomorphic data documenting differential surficial deformation (supplemented by historical accounts of surficiai deformation and earthquake-induced Mississippi River waterfalls and rapids) with the interpretation of existing and recently acquired seismic reflection data, to develop a tectonic model of the near-surface structures in the New Madrid, Missouri, area. This model consists of two primary components: a northnorthwest-trending thrust fault and a series of northeast-trending, strike-slip, tear faults. We conclude that the Reelfoot fault is a thrust fault that is at least 30 km long. We also infer that tear faults in the near surface partitioned the hanging wall into subparallel blocks that have undergone differential displacement during episodes of faulting. The northeast-trending tear faults bound an area documented to have been uplifted at least 0.5 m during the February 7, 1812, earthquake. These faults also appear to bound changes in the surface density of epicenters that are within the modern seismicity, which is occurring in the stepover zone of the left-stepping right-lateral strike-slip fault system of the modern New Madrid seismic zone.