Molecular, morphological and acoustic identification of Eumops maurus and Eumops hansae (Chiroptera: Molossidae) with new reports from Central Amazonia

Eumops maurus and Eumops hansae are rarely captured Neotropical molossid bats for which information on taxonomy, natural history, and spatial distribution are scarce. This translates into a poor understanding of their ecology and limits the delimitation of useful characters for their identification. Here, we describe records of these two molossids from the Central Brazilian Amazon, providing data on their external and craniodental morphology, DNA barcode (COI) sequences complemented by acoustic data for the species. Morphological characters, DNA sequence data and phylogenetic relationships within the genus Eumops were consistent with those previously described for both species. Echolocation call characteristics did not differ significantly so as to be useful for separating E. maurus and E. hansae from other congeners. Our records are, respectively the first and the second for Central Amazonia as one individual previously attributed to Eumops amazonicus from Manaus may be considered a junior synonym for E. hansae. These new records increase the extent of the species’ known ranges, partially filling in previous existing gaps in their distribution in central South America. Our data further suggest that these molossid bats forage in a wider range of habitats than previously thought

Active surveillance of bat rabies in France: A 5-year study (2004–2009)

Active surveillance of bats in France started in 2004 with an analysis of 18 of the 45 bat species reported in Europe. Rabies antibodies were detected in six indigenous species, mainly in Eptesicus serotinus and Myotis myotis, suggesting previous contact with the EBLV-1 rabies virus. Nineteen of the 177 tested bats were shown serologically positive in seven sites, particularly in central and south-western France. Neither infectious viral particles nor viral genomes were detected in 173 and 308 tested oral swabs, respectively. The presence of neutralising antibodies in female bats (18.6%) was significantly higher than in males (5.6%)

A novel measurement method for the extraction of dynamic Volterra Kernels of microwave power amplifiers

A novel measurement method for the behavioral modeling of power amplifiers is presented.The proposed method is based on the use of a specific configuration of a vector network analyzer.The principle consists in measuring under two excitation,a parametric and a conversion gain of an amplifiers versus the magnitude of the large input signal carrier

New trends in characterization and modeling of High Power devices

In this paper, we present some non exhaustive measurement techniques used for characterization and modeling of high power devices. Capabilities offered by pulsed measurements can be an efficient approach to deal with self-heating effects and sometimes trapping effects encountered in microwave high power devices. Pulsed techniques allow to separate self-heating and trapping effects, making like this the modeling process easier. A pulsed RF and pulsed bias load-pull system is then described as well as a time waveform measurement system. Capabilities of these two characterization tools are illustrated with results obtained on a high power silicon bipolar transistor and on a GaAs MESFET device

Theoretical and Experimental Investigations on Nonlinear Capacitance and Loading Effects on Power PHEMT's Linearity

This paper presents a theoretical and experimental analysis of the phase conversion phenomena in a power PHEMT transistor. Relationships between the linearity of the device and the intrinsic gate-source capacitance CGS, gate-drain capacitance CGD ,transconductance GM as well as the load impedance ZL ,are explained. A judicious choice of the transistor’s operating conditions allows to reduce thephaseconversion AM/PM. In the case of PHEMT devices, the behaviors of CGS,CGD,GM elements and ZL value induce internal compensation phenomena between the intrinsic non-linearities

Nonlinear characterization of microwave transistors by the means of pulsed I(V) and pulsed S-Parameters measurements

A versatile pulsed I(V) and 40 GHz pulsed S parameters measurement system of microwave transistors is described Capability of discrimination between thermal and trapping effects with a pulse set-up is demonstrated A method to measure electrically the thermal resistance and capacitance of transistors with a pulse set-up is proposed Finally, it is explained how to derive transistor nonlinear characteristics from these measurements for modeling purposes

Frequency-Domain Simulation and Time-Domain Measurements of a GaN Amplifier driven by M-QAM modulated carrier generator

International audienceA new method is applied to perform, by Harmonic Balance (HB) techniques, the simulation of a GaN Doherty Power Amplifier (DPA) driven by carrier Random-Modulated (RM) signals. This article presents an example (16-QAM) of a driving random modulated voltage generated in the frequency-domain and the software-defined demodulation of the output signal of the DPA implemented with optimal matched filters to respect the Nyquist criteria. It allows the extraction of all the linearity and power metrics performances at design circuit level in the time and frequency-domains. For instance, dynamic power and linearity (Adjacent Channel Power Ratio (ACPR), Error Vector Magnitude (EVM)) performances are calculated. The simulated dynamic results are shown and compared to the measured results obtained on a specific THA-based time-domain calibrated test-bench developed in our laboratory. The Quasi-MMIC DPA under test is driven by a 3.5 GHz carrier frequency modulated with a 16-QAM signal for two different symbol rates.</div

Pulsed-field array performance: A TD analysis

The pulsed-field excited array antenna performance is studied via full time-domain instruments. The directional distribution of radiated energy and the directional (system) fidelity factor are employed as performance metrics. Illustrative numerical experiments highlight the expedient radiation features that are specific to pulse-train excited, linear array antennas. The analysis provides an expedient reference for estimating the detectability of the signals radiated by pulse-train excited array antennas, as needed in ultra-high rate wireless digital transfer