Frequency modulation (FM) and amplitude modulation (AM) detection thresholds were measured at 40 dB sensation level for young (22-28 yrs) and older (44-66 yrs) listeners with normal audiograms for a carrier frequency of 500 Hz and modulation rates of 2 and 20 Hz. The number of modulation cycles, N, varied between 2 and 9. For FM detection, uninformative AM at the same rate as the FM was superimposed to disrupt excitation-pattern cues. For both groups, AM and FM detection thresholds were lower for the 2-Hz than for the 20-Hz rate, and AM and FM detection thresholds decreased with increasing N. Thresholds were higher for older than for younger listeners, especially for FM detection at 2 Hz, possibly reflecting the effect of age on the use of temporal-fine-structure cues for 2-Hz FM detection. The effect of increasing N was similar across groups for both AM and FM. However, at 20 Hz, older listeners showed a greater effect of increasing N than younger listeners for both AM and FM. The results suggest that ageing reduces sensitivity to both excitation-pattern and temporal-fine-structure cues for modulation detection, but more so for the latter, while sparing temporal integration of these cues at low modulation rates.
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http://dx.doi.org/10.1121/1.4953019 | DOI Listing |
Nanotechnology
January 2025
Xidian University, Room 120, G building, Southern campus of Xidian University, Xi'an, Shaanxi, 710126, CHINA.
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School of Instrumentation Science and Opto-electronics Engineering, Beijing Information Science and Technology University, 12 Qinghe Xiaoying East Road, Xisanqi Street, Haidian District, Beijing, Beijing, 100192, CHINA.
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January 2025
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States.
We present direct frequency comb cavity ring-down spectroscopy with Vernier filtering as a straightforward approach to sensitive and multiplexed trace gas detection. The high finesse cavity acts both to extend the interaction length with the sample and as a spectral filter, alleviating the need for dispersive elements or an interferometer. In this demonstration, a free running interband cascade laser was used to generate a comb centered at 3.
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January 2025
James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK.
The time-resolved detection of mid- to far-infrared electric fields absorbed and emitted by molecules is among the most sensitive spectroscopic approaches and has the potential to transform sensing in fields such as security screening, quality control, and medical diagnostics. However, the sensitivity of the standard detection approach, which relies on encoding the far-infrared electric field into amplitude modulation of a visible or near-infrared probe laser pulse, is limited by the shot noise of the latter. This constraint cannot be overcome without using a quantum resource.
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January 2025
Escuela de Química, Universidad Industrial de Santander, Bucaramanga, Colombia.
Microorganisms tend to accumulate on surfaces, forming aggregates such as biofilms, which grant them resistance to various environmental stressors and antimicrobial agents. This ability has hindered the effective treatment of diseases caused by pathogenic microorganisms, including Salmonella, which is responsible for a significant number of deaths worldwide. This study aimed to compare the metabolic profiles of planktonic and sessile cells of Salmonella Enteritidis using a metabolomics approach.
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