4,785 research outputs found
Fletcher Menard, Joyce Interview
No full textOral history interview of Joyce Fletcher. Interview conducted by Jessica Oldham via Zoom in Orlando, FL on July 29th, 2021
A Conversation with Jessica B. Harris
No full textA conversation with culinary historian and award-winning author Jessica B. Harris, moderated by Gabrielle Fulton Ponder
Jessica Stremer: Cook Prize 2024, Silver Medal Acceptance Speech
No full textAuthor Jessica Stremer gives an acceptance speech for Great Carrier Reef (Holiday House)https://educate.bankstreet.edu/cook/1013/thumbnail.jp
Jessica Pierce: The Last Walk: Caring for Our Animal Companions
No full textBioethicist and author Jessica Pierce will discuss end-of-life care, dying, and euthanasia in the lives of our companion animals.https://thekeep.eiu.edu/humanitiescenter_authenticity1314/1003/thumbnail.jp
Is off-frequency overshoot caused by adaptation of suppression?
No full textThis study is concerned with the mechanism of off-frequency overshoot. Overshoot refers to the phenomenon whereby a brief signal presented at the onset of a masker is easier to detect when the masker is preceded by a “precursor” sound (which is often the same as the masker). Overshoot is most prominent when the masker and precursor have a different frequency than the signal (henceforth referred to as “off-frequency overshoot”). It has been suggested that off-frequency overshoot is based on a similar mechanism as “enhancement,” which refers to the perceptual pop-out of a signal after presentation of a precursor that contains a spectral notch at the signal frequency; both have been proposed to be caused by a reduction in the suppressive masking of the signal as a result of the adaptive effect of the precursor (“adaptation of suppression”). In this study, we measured overshoot, suppression, and adaptation of suppression for a 4-kHz sinusoidal signal and a 4.75-kHz sinusoidal masker and precursor, using the same set of participants. We show that, while the precursor yielded strong overshoot and the masker produced strong suppression, the precursor did not appear to cause any reduction (adaptation) of suppression. Predictions based on an established model of the cochlear input–output function indicate that our failure to obtain any adaptation of suppression is unlikely to represent a false negative outcome. Our results indicate that off-frequency overshoot and enhancement are likely caused by different mechanisms. We argue that overshoot may be due to higher-order perceptual factors such as transient masking or attentional diversion, whereas enhancement may be based on mechanisms similar to those that generate the Zwicker tone
Providence College Faculty Author Series 2014-2015: Dr. Jessica Mulligan
No full textIn this installment of the Faculty Authors Series, Dr. Jessica Mulligan of the Health Policy & Management department discusses her book Unmanageable Care: An Ethnography of Health Care Privatization in Puerto Rico - elucidating the history and contemporary state of the Puerto Rican healthcare system
Effect of contralateral medial olivocochlear feedback on perceptual estimates of cochlear gain and compression
No full textThe active cochlear mechanism amplifies responses to low-intensity sounds, compresses the range of input sound intensities to a smaller output range, and increases cochlear frequency selectivity. The gain of the active mechanism can be modulated by the medial olivocochlear (MOC) efferent system, creating the possibility of top-down control at the earliest level of auditory processing. In humans, MOC function has mostly been measured by the suppression of optoacoustic emissions (OAEs), typically as a result of MOC activation by a contralateral elicitor sound. The exact relationship between OAE suppression and cochlear gain reduction, however, remains unclear. Here, we measured the effect of a contralateral MOC elicitor on perceptual estimates of cochlear gain and compression, obtained using the established temporal masking curve (TMC) method. The measurements were taken at a signal frequency of 2 kHz and compared with measurements of click-evoked OAE suppression. The elicitor was a broadband noise, set to a sound pressure level of 54 dB to avoid triggering the middle ear muscle reflex. Despite its low level, the elicitor had a significant effect on the TMCs, consistent with a reduction in cochlear gain. The amount of gain reduction was estimated as 4.4 dB on average, corresponding to around 18 % of the without-elicitor gain. As a result, the compression exponent increased from 0.18 to 0.27
Providence College Faculty Author Series 2014-2015: Dr. Jessica Mulligan
No full textIn this installment of the Faculty Authors Series, Dr. Jessica Mulligan of the Health Policy & Management department discusses her book Unmanageable Care: An Ethnography of Health Care Privatization in Puerto Rico - elucidating the history and contemporary state of the Puerto Rican healthcare system
Is overshoot caused by an efferent reduction in cochlear gain?
No full textUnder certain conditions, detection of a masked tone is improved by a preceding sound (“precursor”). This phenomenon is referred to as the “temporal effect” or “overshoot”. A prevalent model of overshoot, referred to as the “gain reduction model”, posits that overshoot is caused by efferent reduction in cochlear gain mediated by the medial olivocochlear (MOC) bundle. The model predicts that reduction in cochlear gain will reduce masking when masking is suppressive or when masking is excitatory and the signal-to-masker ratio is high. This study was aimed at testing the validity of these predictions. It consisted of two experiments. The first experiment investigated the relative contributions of suppressive versus excitatory masking to overshoot. The signal was a short 4-kHz tone pip, and the masker and precursor were limited to contain energy either only within (on-frequency) or only outside (off-frequency) the cochlear filter around the signal frequency. The on-frequency masker would be expected to cause mainly excitatory masking, whereas masking by the off-frequency masker would be expected to be mainly suppressive. Only the off-frequency masker and precursor yielded significant overshoot. This suggests that measurable overshoot requires suppressive masking. The second experiment sought to quantify the effect of a precursor on cochlear suppression more directly by measuring the amount of suppression caused by a 4.75-kHz suppressor on a lower-frequency (4-kHz) suppressee with and without a precursor present. Suppression was measured using a forward-masking paradigm. While we found large suppression and large overshoot, we found no reduction in suppression by the precursor. This is contrary to the gain reduction model. Taken together, our results indicate that measurable overshoot requires off-frequency masking and that off-frequency overshoot must be caused by a mechanism other than MOC-mediated reduction in cochlear suppression
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