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Abstract-This paper presents a dual-band tunable bandpass filter with independently controllable dual passbands based on a novel asymmetric λ/4 resonator pair with shared via-hole ground. Because two separated passbands can be independently generated by the two λ/4 resonators with different electric lengths, the asymmetric λ/4 resonator pair can realize flexible passband allocation when it is utilized to design dual-band filters. Two varactors are placed at the two open circuit ends of the asymmetric λ/4 resonator pair to control the two dominant resonant frequencies, respectively. A prototype tunable dual-band filter with Chebyshev response is designed and fabricated. The measured results are in good agreement with the full-wave simulated ones. The results show that the first passband varies in a frequency range from 0.88 GHz to 1.12 GHz with the 3-dB fractional bandwidth of 5.1%-6.4%, while the second passband can be tuned from 1.5 GHz to 1.81 GHz with the 3-dB fractional bandwidth of 5.4%-6.4%.

The complete mitochondrial genome sequence of the Feirana taihangnica (Anura: Dicroglossidae) was determined. It is a circular molecule of 17,412 bp in length, containing 13 protein-coding genes, 2 ribosomal RNAs, 22 transfer RNAs, and a control region. The tRNA(Thr) gene located in the LTPF tRNA gene cluster typically found in other anurans is absent from the F. taihangnica mtDNA and a tandem duplication of tRNA(Met) gene is observed. The A+T content of the overall base compositon of H-strand is 57.2% and the length of control region is 1972 bp with 61.8% A+T content.

In this paper, we characterized the mitogenomes of three 'eyed' turtles, the Beal's Eyed turtle (Sacalia bealei), the Four Eye-spotted turtle (S. quadriocellata), and the Hainan Four Eye-spotted turtle which was a unique lineage in the four-eyed turtle and considered as an independent species S. insulensis recently. The full lengths of the S. bealei and S. quadriocellata mitogenomes are 16,564 bp, and 16,555 bp, respectively, while the length of partial mitochondrial genome of S. insulensis is 16,433 bp without tailed part of D-loop. All the genes exhibit the typical mitochondrial gene arrangement and transcribing directions of turtles. Phylogenetic analysis indicating that a deep divergence about 7.8% p distance was found between S. bealei and (S. quadriocellata þ S. insulensis), and the divergence (2.8% in patristic distance) between S. quadriocellata and S. insulensis is comparable with other closely related species in turtles.

Hearing sensitivity is of general interest from the perspective of understanding the functionality and evolution of vertebrate auditory systems. Sexual dimorphism of auditory systems has been reported in several species of vertebrates, but little is known about this phenomenon in turtles. Some morphological characteristics, such as middle ear and tympanic membrane that influence the hearing sensitivity of animals can result in hearing sexual dimorphism. To examine whether sexual dimorphism in hearing sensitivity occurs in turtles and to compare hearing characteristics with respect to the shape of the tympanic membrane, we measured the hearing sensitivity and tympanum diameter in both sexes of Trachemys scripta elegans. The results showed that, with the exception of 0.9 kHz, auditory brainstem response thresholds were significantly lower in females than in males for frequencies in the 0.2–1.1 kHz range, indicating that the hearing of females shows greater sensitivity. No significant differences were detected in the tympanum diameter of both sexes. These results showed that sexually dimorphic hearing sensitivity has evolved in turtles; however, this difference does not appear to be related to differences in the size of the tympanic membrane. The possible origin and function of the sexual differences in auditory characteristic are discussed.