The peripheral auditory characteristics of noctuid moths: responses to the search-phase echolocation calls of bats

1996 ◽  
Vol 199 (4) ◽  
pp. 847-856 ◽  
Author(s):  
D Waters ◽  
G Jones
Keyword(s):  
Short Duration ◽  
High Frequency ◽  
Temporal Structure ◽  
Temporal Integration ◽  
Agrotis Segetum ◽  
Integration Time ◽  
Constant Frequency ◽  
Low Intensity ◽  
Long Duration ◽  
The Central Nervous System

The noctuid moths Agrotis segetum and Noctua pronuba show peak auditory sensitivity between 15 and 25 kHz, and a maximum sensitivity of 35 dB SPL. A. segetum shows a temporal integration time of 69 ms. It is predicted that bats using high-frequency and short-duration calls will be acoustically less apparent to these moths. Short-duration frequency-modulated (FM) calls of Plecotus auritus are not significantly less acoustically apparent than those of other FM bats with slightly longer call durations, based on their combined frequency and temporal structure alone. Long-duration, high-frequency, constant-frequency (CF) calls of Rhinolophus hipposideros at 113 kHz are significantly less apparent than those of the FM bats tested. The predicted low call apparency of the 83 kHz CF calls of R. ferrumequinum appears to be counteracted by their long duration. It is proposed that two separate mechanisms are exploited by bats to reduce their call apparency, low intensity in FM bats and high frequency in CF bats. Within the FM bats tested, shorter-duration calls do not significantly reduce the apparency of the call at the peripheral level, though they may limit the amount of information available to the central nervous system.

scholarly journals Feedback-controlled stimulation enhances human paralyzed muscle performance

2006 ◽  
Vol 101 (5) ◽  
pp. 1312-1319 ◽  
Author(s):  
Richard K. Shields ◽  
Shauna Dudley-Javoroski ◽  
Keith R. Cole
Keyword(s):  
Electrical Stimulation ◽  
High Frequency ◽  
Neuromuscular Electrical Stimulation ◽  
Peak Torque ◽  
Open Loop ◽  
Muscle Performance ◽  
Constant Frequency ◽  
Extensive Training ◽  
Long Duration ◽  
Repetitive Stress

Chronically paralyzed muscle requires extensive training before it can deliver a therapeutic dose of repetitive stress to the musculoskeletal system. Neuromuscular electrical stimulation, under feedback control, may subvert the effects of fatigue, yielding more rapid and extensive adaptations to training. The purposes of this investigation were to 1) compare the effectiveness of torque feedback-controlled (FDBCK) electrical stimulation with classic open-loop constant-frequency (CONST) stimulation, and 2) ascertain which of three stimulation strategies best maintains soleus torque during repetitive stimulation. When torque declined by 10%, the FDBCK protocol modulated the base stimulation frequency in three ways: by a fixed increase, by a paired pulse (doublet) at the beginning of the stimulation train, and by a fixed decrease. The stimulation strategy that most effectively restored torque continued for successive contractions. This process repeated each time torque declined by 10%. In fresh muscle, FDBCK stimulation offered minimal advantage in maintaining peak torque or mean torque over CONST stimulation. As long-duration fatigue developed in subsequent bouts, FDBCK stimulation became most effective (∼40% higher final normalized torque than CONST). The high-frequency strategy was selected ∼90% of the time, supporting that excitation-contraction coupling compromise and not neuromuscular transmission failure contributed to fatigue of paralyzed muscle. Ideal stimulation strategies may vary according to the site of fatigue; this stimulation approach offered the advantage of online modulation of stimulation strategies in response to fatigue conditions. Based on stress-adaptation principles, FDBCK-controlled stimulation may enhance training effects in chronically paralyzed muscle.

scholarly journals Effects of Static Stretching With High-Intensity and Short-Duration or Low-Intensity and Long-Duration on Range of Motion and Muscle Stiffness

2020 ◽  
Vol 11 ◽  
Author(s):  
Taizan Fukaya ◽  
Ryosuke Kiyono ◽  
Shigeru Sato ◽  
Kaoru Yahata ◽  
Koki Yasaka ◽  
...  
Keyword(s):  
Elastic Modulus ◽  
Range Of Motion ◽  
Short Duration ◽  
High Intensity ◽  
Muscle Stiffness ◽  
Static Stretching ◽  
Low Intensity ◽  
Shear Elastic Modulus ◽  
Passive Torque ◽  
Long Duration

This study investigated the effects of static stretching (SS) delivered with the same load but using two protocols – high-intensity and short-duration and low-intensity and long-duration – on range of motion (ROM) and muscle stiffness. A total of 18 healthy students participated in the study. They randomly performed high-intensity and short-duration (120% and 100 s) or low-intensity and long-duration (50% and 240 s) SS. Outcomes were assessed on ROM, passive torque at dorsiflexion ROM, and shear elastic modulus of the medial gastrocnemius before and after static stretching. The results showed that ROM increased significantly at post-stretching compared to that at pre-stretching in both high-intensity and short-duration [+6.1° ± 4.6° (Δ25.7 ± 19.9%)] and low-intensity and long-duration [+3.6° ± 2.3° (Δ16.0 ± 11.8%)]. Also, the ROM was significantly higher at post-stretching in high-intensity and short-duration conditions than that in low-intensity and long-duration. The passive torque at dorsiflexion ROM was significantly increased in both high-intensity and short-duration [+5.8 ± 12.8 Nm (Δ22.9 ± 40.5%)] and low-intensity and long-duration [+2.1 ± 3.4 Nm (Δ6.9 ± 10.8%)] conditions, but no significant differences were observed between both conditions. The shear elastic modulus was significantly decreased in both high-intensity and short-duration [−8.8 ± 6.1 kPa (Δ − 38.8 ± 14.5%)] and low-intensity and long-duration [−8.0 ± 12.8 kPa (Δ − 22.2 ± 33.8%)] conditions. Moreover, the relative change in shear elastic modulus in the high-intensity and short-duration SS was significantly greater than that in low-intensity and long-duration SS. Our results suggest that a higher intensity of the static stretching should be conducted to increase ROM and decrease muscle stiffness, even for a short time.

Diphasic and Polyphasic Temporal Modulations Multiply Apparent Spatial Frequency

Perception ◽  
1974 ◽  
Vol 3 (3) ◽  
pp. 323-336 ◽  
Author(s):  
V Virsu ◽  
G Nyman ◽  
P K Lehtiö
Keyword(s):  
Spatial Frequency ◽  
High Frequency ◽  
Light Adaptation ◽  
Second Harmonic ◽  
Temporal Integration ◽  
Low Frequency ◽  
Integration Time ◽  
Sinusoidal Grating ◽  
Spatial Effects ◽  
Spatial Integration

The effects of diphasic and polyphasic flicker on apparent spatial frequency were studied in several experiments through simultaneous spatial-frequency matches. In diphasic flicker the spatial phase of a sinusoidal grating alternated between two values in a counterphase fashion, and in polyphasic flicker the spatial phases of gratings were varied discretely in time in a variable number of steps. Both forms of flicker increased the apparent spatial frequency at low temporal frequencies, in the same manner as low-frequency monophasic flicker has been found to do. At high temporal frequencies, diphasic flicker doubled the apparent spatial frequency, as reported by Kelly (1966). We found that through high-frequency polyphasic flicker the spatial effect that Kelly mentions can be generalised to spatial frequency multiplication: polyphasic flicker produces not only the apparent second harmonic but also the third and the fourth harmonic, depending on the phase parameters. A numerical analysis showed that the spatial high-frequency effects can be explained through temporal integration of nonlinearly filtered input signals if a value of 200 td(1) is assumed for the nonlinearity constant in [Formula: see text] where B( I) is the brightness, I is the retinal illuminance, K is a scale constant, and I½ is the constant of nonlinearity. A minimum value of 60 ms had to be estimated for integration time. An investigation of the integration time with diphasic flicker indicated that spatial integration time decreases when the level of light adaptation increases, and that the integration time for spatial effects is longer than for flicker fusion. The spatial effects of low-frequency and high-frequency flicker differ in so many respects that different neural processes have to be postulated for their explanation.

The collection of multiple saliva samples from pigs and the effect on adrenocortical activity

2013 ◽  
Vol 93 (3) ◽  
pp. 329-333 ◽  
Author(s):  
Nigel J. Cook ◽  
Stephanie M. Hayne ◽  
Fiona C. Rioja-Lang ◽  
Allan L. Schaefer ◽  
Harold W. Gonyou
Keyword(s):  
Short Duration ◽  
Salivary Cortisol ◽  
High Frequency ◽  
Low Frequency ◽  
Weight Class ◽  
Adrenocortical Activity ◽  
Long Duration ◽  
Sampling Protocols ◽  
Repeated Sampling ◽  
Multiple Samples

Cook, N. J., Hayne, S. M., Rioja-Lang, F. C., Schaefer, A. L. and Gonyou, H. W. 2013. The collection of multiple saliva samples from pigs and the effect on adrenocortical activity. Can. J. Anim. Sci. 93: 329–333. The validity of collecting multiple saliva samples for the measurement of cortisol was tested in two sampling regimes in two weight classes of grower pigs (50 and 100 kg). The sampling regimes were a high-frequency, short-duration (HFSD) protocol involving collection of multiple samples within approximately 2 min of each other over a period 30 min. The second regime was a low-frequency, long-duration (LFLD) protocol in which samples were collected every 30 min for 3 h. Both sampling regimes were applied to individually housed pigs. The effect of repeated sampling of a focal pig on its cohorts in a group-housed pen was tested using the LFLD regime. There was no evidence of an effect of either of the sampling protocols on salivary cortisol concentrations in individually housed or group-housed pigs. There was some evidence that higher concentrations of salivary cortisol were associated with longer individual sampling durations in the HFSD regime for animals in the 50-kg weight class but not in the 100-kg weight class. The evidence from these experiments indicates that the collection of multiple saliva samples does not affect salivary cortisol concentrations in grower pigs, but that collection of individual samples in as short a time as possible would be prudent to avoid sampling effects in younger animals.

DEPENDENCE OF INTEGRATED DURATION OF METEOR ECHOES ON WAVELENGTH AND SENSITIVITY

1954 ◽  
Vol 32 (7) ◽  
pp. 450-467 ◽  
Author(s):  
D. W. R. McKinley
Keyword(s):  
Short Duration ◽  
High Frequency ◽  
Time Of Day ◽  
Very High Frequency ◽  
Forward Scatter ◽  
Long Duration ◽  
Meteor Trails ◽  
Cedar Rapids ◽  
Very High

The reflecting properties of short-duration and long-duration echoes from meteor trails are examined. For short-duration echoes only, the observed relation between relative numbers and durations of meteor echoes is independent of wavelength, the time of day, or the presence of a strong shower. Integrated duration times are determined from back-scatter experiments on 9.22 m., 5.35 m., and 2.83 m., and are found to vary with the 3.5th power of the wavelength, for either short- or long-duration echoes. The integrated echo power depends on the 6th power of the wavelength. The effect of changing the equipment sensitivity is considered. The data from the back-scatter observations are used to predict the integrated duration times in the forward-scatter case, and in particular, it is shown that the results of the Cedar Rapids – Sterling very-high-frequency experiment may be explained by meteoric reflections.

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