Efforts to study the social acoustic signaling behavior of delphinids have traditionally been restricted to audio-range (<20 kHz) analyses. To explore the occurrence of communication signals at ultrasonic frequencies, broadband recordings of whistles and burst pulses were obtained from two commonly studied species of delphinids, the Hawaiian spinner dolphin (Stenella longirostris) and the Atlan...

Here we report a compact monolithic 2000nm pulsed laser with a single spatial mode output, ~1.5ns pulse duration, 8kW peak power and >200mW average power at 20 kHz repetition rate. The gain-switched laser, consisting of a pair of fiber Bragg gratings and 0.5m of thulium-doped single cladding fiber, was core pumped by a high peak power pulsed 1.5 m laser. When the input pulse energy of the 20 kH...

We investigated the noise levels in cell-attached patch capacitance recordings with a lock-in amplifier. The capacitance noise level decreases with increasing sine wave frequency up to 20-40 kHz. With a 20-mV rms sine wave the rms noise level above 8 kHz is <50 aF. With increasing sine wave amplitudes a further reduction down to 14 aF could be achieved. Capacitance measurements with a lock-in a...

Background: This work evaluated the efficiency of common ultrasound stimulation (U.S.S) types on bacterial growth in vitro using clinically relevant conditions.Objective: To estimate different frequencies ultrasound bactericidal ability on bacteria in bacteria of Pseudomonas Aeruginosa. Methods: Six types of U.S.S (continuous wave, 7w/cm2, 20 KHz; continuous wave, 35w/0.8L, 40 KHz; continuous ...

We examined aspects of hearing in the red bat (Lasiurus borealis) related to its use of biosonar. Evoked potential audiograms, obtained from volume-conducted auditory brainstem responses, were obtained in two bats, and the sound pressure transformation of the pinna was measured in three specimens. Field-recorded echolocation signals were analysed for comparison. The fundamental sonar search cal...

Behavioral and auditory evoked potential (AEP) audiograms of a false killer whale were measured using the same subject and experimental conditions. The objective was to compare and assess the correspondence of auditory thresholds collected by behavioral and electrophysiological techniques. Behavioral audiograms used 3-s pure-tone stimuli from 4 to 45 kHz, and were conducted with a go/no-go modi...

This article reports the discovery of a new genus and three species of predaceous katydid (Insecta: Orthoptera) from Colombia and Ecuador in which males produce the highest frequency ultrasonic calling songs so far recorded from an arthropod. Male katydids sing by rubbing their wings together to attract distant females. Their song frequencies usually range from audio (5 kHz) to low ultrasonic (...

Electrical impedance tomography (EIT) merupakan salah satu metode citra yang didasarkan pada distribusi konduktivitas listrik suatu objek. Hasil rekonstruksi dengan teknik EIT sangat bergantung kemampuan sistem instrumentasinya (hardware) untuk menghasilkan data akurat. Salah bagian penting dalam membangun adalah sumber sinyal bolak balik biasa disebut Voltage-controlled oscillator (VCO). Pada ...