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1.
1.  Echolocating bats (Eptesicus fuscus) were trained to discriminate between simulated targets consisting of one or two echo-wavefronts with internal time delays of up to 100 s. Spectral and temporal properties and total signal energy of the targets were evaluated and predictions for performances of bats derived from receiver models were compared with measured performances.
2.  Eptesicus fuscus was able to discriminate a one-wavefront target from two-wavefront targets with distinct internal time delays (12 s, 32–40 s and 52–100 s). Performance was not affected by changes in total signal energy. Bats also successfully discriminated between two-wavefront targets with different internal time delays.
3.  Performance predicted from differences in total energy between targets did not match the measured performance, indicating that bats did not rely on total echo energy. This finding is also supported by the behavioral data. Performance predicted from spectral and temporal receiver models both matched the measured performance and, therefore, neither one of these models can be favored over the other.
4.  The behavioral data suggest that Eptesicus fuscus did not transform echo information into estimates of target range separation and, therefore, did not perceive the two wavefronts of each simulated two-wavefront echo as two separate targets.
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2.
1.  Most studies examining interactions between insectivorous bats and tympanate prey use the echolocation calls of aerially-feeding bats in their analyses. We examined the auditory responses of noctuid (Eurois astricta) and notodontid (Pheosia rimosa) moth to the echolocation call characteristics of a gleaning insectivorous bat, Myotis evotis.
2.  While gleaning, M. Evotis used short duration (mean ± SD = 0.66 ± 0.28 ms, Table 2), high frequency, FM calls (FM sweep = 80 – 37 kHz) of relatively low intensity (77.3 + 2.9, –4.2 dB SPL). Call peak frequency was 52.2 kHz with most of the energy above 50 kHz (Fig. 1).
3.  Echolocation was not required for prey detection or capture as calls were emitted during only 50% of hovers and 59% of attacks. When echolocation was used, bats ceased calling 324.7 (±200.4) ms before attacking (Fig. 2), probably using prey-generated sounds to locate fluttering moths. Mean call repetition rate during gleaning attacks was 21.7 (±15.5) calls/s and feeding buzzes were never recorded.
4.  Eurois astricta and P. rimosa are typical of most tympanate moths having ears with BFs between 20 and 40 kHz (Fig. 3); apparently tuned to the echolocation calls of aerially-feeding bats. The ears of both species respond poorly to the high frequency, short duration, faint stimuli representing the echolocation calls of gleaning M. evotis (Figs. 4–6).
5.  Our results demonstrate that tympanate moths, and potentially other nocturnal insects, are unable to detect the echolocation calls typical of gleaning bats and thus are particularly susceptible to predation.
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3.
1.  The reactions of tympanic nerve fibers ofLocusta migratoria were recorded by glass microelectrodes in the metathoracic ganglion.
2.  The units were classified by frequency-, intensity-, and directional characteristics as well as by their response pattern. The response to speciesspecific song is compared with the response to song ofEphippiger ephippiger.
3.  The physiological properties lead to a classification into three types of low-frequency neurons (characteristic frequency 3.5–4 kHz; 4kHz; 5.5–6 kHz) and one type of high-frequency neuron (12–20 kHz). This is similar to other species (Gray, 1960, Michelsen, 1971).
4.  Intensity-coding is done by sharp rising intensity characteristics and by different absolute thresholds of the units.
5.  There is a marked directional sensitivity with some differences between LF and HF units. In the low frequency range the tympanal organ seems to react as a pressure gradient receiver; for high frequencies another mechanism is discussed.
6.  No filtering of species-specific song takes place at the level of the receptor cells.
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4.
1.  The cochlea of the horseshoe bat,Rhinolophus ferrumequinum, was frequency mapped by exposing for 30 min to one or two continuous pure tones of intensities between 70 and 110 dB SPL. The evaluation was made by differentiating between normal and swollen nuclei of the outer hair cells (OHC) of the organ of Corti and by measuring the diameter of the nuclei of the OHC.
2.  In control animals the radial diameter of the OHC nuclei varies systematically from a mean of 2.85 m at the base to 3.2 um at the apex (Fig. 1).
3.  All frequencies used for exposure were normalized to the resting frequency (FR), which is the frequency of the pure tone component of the orientation sound in a non-flying bat. The individual FR lay between 82.6 and 83.3 kHz.
4.  For analysing the small frequencies between 83.0 to 86.0 kHz in which relevant echoes occur, 3.15 mm length of the basilar membrane is used, about the same length as for the octaves from FR/4 to FR/2 (2.85 mm) and from FR/2 to FR (3.2 mm) (Fig. Ca, b).
5.  The discontinuity of the mechanical data at 4.5 mm of the length of the basilar membrane (part I of this paper) coincides with FR and the less pronounced discontinuity at 7.8 mm coincides with FR/2.
6.  Location and mechanism of the auditory filter are discussed.
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5.
1.  Up to 9 kHz, the tympanal membrane of the grasshopper Chorthippus biguttulus responds with equal sensitivity at the attachment sites of the low and the high-frequency receptors; at the latter site it is also particularly sensitive between 10 and 20 kHz.
2.  The frequency spectra of the songs of both sexes exhibit maxima at 7–8 kHz, to which the membrane is well matched. In the high-frequency region, where the male songs have a peak at 30 kHz, there is no corresponding maximum in the membrane oscillation.
3.  Because the tympanal membrane is immediately adjacent to air sacs in the tracheal system, it is deflected inward and outward by as much as 80 m during the respiratory cycle.
4.  Measurements by laser vibrometry show that acoustically induced membrane oscillations are attenuated severely due to the respiratory displacement of the membrane for frequencies up to 10–12 kHz. By contrast, at higher frequencies the membrane sensitivity is doubled or tripled.
5.  As a result of these membrane effects, the discharge in the tympanal nerve was profoundly reduced in the low-frequency range, whereas above 11 kHz there was a marked increase. This modulation of auditory sensitivity affects the animals' ability to detect conspecific songs.
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6.
1.  Within the tonotopic organization of the inferior colliculus two frequency ranges are well represented: a frequency range within that of the echolocation signals from 50 to 100 kHz, and a frequency band below that of the echolocation sounds, from 10 to 35 kHz. The frequency range between these two bands, from about 40 to 50 kHz is distinctly underrepresented (Fig. 3B).
2.  Units with BFs in the lower frequency range (10–25 kHz) were most sensitive with thresholds of -5 to -11 dB SPL, and units with BFs within the frequency range of the echolocation signals had minimal thresholds around 0 dB SPL (Fig. 1).
3.  In the medial part of the rostral inferior colliculus units were encountered which preferentially or exclusively responded to noise stimuli. — Seven neurons were found which were only excited by human breathing noises and not by pure tones, frequency modulated signals or various noise bands. These neurons were considered as a subspeciality of the larger sample of noise-sensitive neurons. — The maximal auditory sensitivity in the frequency range below that of echolocation, and the conspicuous existence of noise and breathing-noise sensitive units in the inferior colliculus are discussed in context with the foraging behavior of vampire bats.
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7.
We have identified a nerve carrying auditory afferents and characterized their physiological responses in the tiger beetle,Cicindela marutha.
1.  The tympana are located at the lateral margins of the first abdominal tergum. The nerve carrying the tympanal afferents is a branch of the dorsal root from the first abdominal ganglion.
2.  Both male and female auditory afferent responses are sharply tuned to 30 kHz with sensitivities of 50–55 dB SPL.
3.  The auditory afferents show little adaptation and accurately code the temporal characteristics of the stimulus with the limit of a resolution of 6–10 ms.
4.  The difference in threshold between contralateral and ipsilateral afferents for lateral stimuli is greatest at 30 kHz and is at least 10–15 dB.
5.  Ablation studies indicate that the floppy membrane in the anterolateral corner of the tympanum is crucial for transduction while the medial portion of the tympanum is less important.
6.  The tiger beetle and acridid (locust and grasshopper) ears have evolved independently from homologous peripheral structures. The neural precursor of the tympanal organs in both animals is likely the pleural chordotonal organ of the first abdominal segment.
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8.
Summary Echolocating bats judge the distance to a target on basis of the delay between the emitted cry and the returning echo. In a phantom echo set-up it was investigated how changes in the time-frequency structure of synthetic echoes affect ranging accuracy of big brown bats, Eptesicus fuscus.A one channel phantom target simulator and a Y/N paradigm was used. Five Eptesicus fuscus were trained to discriminate between phantom targets with different virtual distances (delays). The phantom echo was stored in a memory and broadcast from a loudspeaker after a certain delay following the bat's triggering of the system via a trigger microphone. The ranging accuracy was compared using 5 different signals with equal energy as phantom echoes: a standard cry (a natural bat cry), two kinds of noise signals, a high pass, and a low pass filtered version of the standard cry.The standard cry was recorded from one of the bats while judging the distance to a real target. The duration was 1.1 ms, the first harmonic swept down from 55 to 25 kHz and there was energy also in the second and third harmonic. Both noise signals had the same duration, power spectrum, and energy as the standard cry. One noise signal was stored in a memory and hence was exactly the same each time the bat triggered the system. The other variable noise signal was produced by storing the envelope of the standard cry and multiplying on-line with band pass filtered noise. The time-frequency structure (e.g. rise time) of this noise signal changed from triggering to triggering. The filtered signals were produced by either 40 kHz high pass or 40 kHz low pass filtering of the standard cry.The range difference thresholds for the 5 bats were around 1–2 cm (51–119 us) using the standard cry as echo. The range difference threshold with both noise signals was 7–8 cm (around 450 s delay difference). The 40 kHz high pass filtered cry increased the threshold to approximately twice the threshold with the standard cry. With the 40 kHz low pass filtered cry the threshold was increased 2.5–3 times relative to the threshold with the standard cry. A single bat was tested with a signal filtered with a 55 kHz low pass filter leaving the whole first harmonic. The threshold was the same as that with the standard signal.The reduced ranging accuracy with the filtered signals indicates that the full band width of the first harmonic is utilised for ranging by the bats. The substantial reduction in accuracy with the noise signals indicates that not only the full band width but also the orderly time-frequency structure (the FM sweep) of the cry is important for ranging in echolocating bats.Abbreviations FM frequency modulated - CF constant frequency - peSPL peak equivalent sound pressure level - SD standard deviation - SE standard error of mean - EPROM erasable programmable read only memory - FFT fast Fourier transform - S/N signal-to-noise ratio  相似文献   

9.
Twelve of the main European LCA software packages currently available are examined wirh the aim of establishing which are the most appropriate for LCAs on industrial processes. The packages performances are assessed in terms of
–  • Volume of Data
–  • WindowsTM environment
–  • Network Capabilities
–  • Impact Assessment
–  • Graphical representation of the inventory results
–  • Sensitivity analysis
–  • Units
–  • Cost
–  • User Support
–  • Flow Diagrams
–  • Burdens allocation
–  • Transparency of data
–  • Input & output parameters
–  • Demo version
–  • Quality of data
The review concludes with a Specification Table which summarises the facilities available on each software package. The general conclusion from this study is that for industrially based LCAs, there are four packages which may offer advantages over the rest. These are The Boustead Model, The Ecobilan Group’s TEAM™, PEMS 3.0 and SimaPro 3.1.  相似文献   

10.
J. Robb 《Human Evolution》1994,9(3):215-229
In recent years anthropologists have made much progress in understanding ancient activities from skeletal remains. In this paper, material from the Iron Age cemetery at Pontecagnano (VII-IV century BC) is used to illustrate activity-related traits of eight basic categories:
(1)  idiosyncratic patterns of dental wear
(2)  activity-related articular degeneration
(3)  non-pathological functional alterations (neoformations, contact facets)
(4)  mechanical remodelling of bone architecture
(5)  enthesopathies (muscular lesions)
(6)  traumatic lesions
(7)  activity-related pathologies
(8)  activity-related nutritional characteristics
These traits, and others, can be used not only singly but in conjunction to define (a) patterns of activity and occupational specialization for individuals, and (b) distributions within society reflecting the basic division of labor by geneder and class.  相似文献   

11.
3DFS is a 3D flexible searching system for lead discovery. Version 1.0 of 3DFS was published recently (Wang, T.; Zhou, J. J. Chem. Inf. Comput. Sci., 1998, 38, 71–77). Here version 1.2 represents a substantial improvement over version 1.0. There are six major changes in version 1.2 compared to version 1.0.
1.  A new rule of aromatic ring recognition.
2.  The inclusion of multiple-type atoms and chains in queries.
3.  The inclusion of more spatial constraints, especially the directions of lone pairs.
4.  The improvement of the query file format.
5.  The addition of genetic search for flexible search.
6.  An output option for generating MOLfiles of hits.
Besides the above, this paper supplies:
1.  More query examples.
2.  A comparison between genetic search and Powell optimization.
3.  More detailed comparison between 3DFS and Chem-X.
4.  A preliminary application of 3DFS to K+ channel opener studies.
Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1007/s0089490050231  相似文献   

12.
Conclusions  
(1)  The aminoesters inhibit glucose-stimulated proton extrusion by yeast cells.
(2)  The inhibitory activity depends on aliphatic carbon chain length.
(3)  The inhibition of proton extrusion is concentration-dependent.
(4)  The aminoesters stimulate quinacrine accumulation in vacuoles of yeast cells so they should possess affinities for lysosomes.
This work was supported byKBN grant no. 7 A203 013 07.  相似文献   

13.
1.  The overall rate of feeding at 28°C bears an inverse relationship to size; the time course of feeding appears to be size-independent and shows a decline with increase in time.
2.  Absorption efficiency is independent of size.
3.  The rates of absorption and conversion and conversion efficiency are inversely related to size.
4.  The rate of feeding is reflected on the rates of absorption and conversion.
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14.
Oncostatin M, a multifunctional cytokine   总被引：6，自引：0，他引：6  
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15.
In the rift valley (North-East of France/South-West of Germany), the Rhine runs freely for 300 km from South to North. The absence of natural obstacles allows the development of a very regular profile of the river. We have therefore an opportunity to study very gradual modifications of the alluvial forest communities of the fluvial corridor from upstream to downstream, according to the gradual evolution of the ecological factors, related to slope decrease and hydrological modifications.We describe, from Basel to Mainz:
1)  modification of dynamic processes in the forest communities such as successional sequences or sylvigenetic mosaïcs of the terminal stages.
2)  modification of species richness.
3)  reduction of species diversity.
4)  simplification of the forest stratification.
5)  modification of efficiency of the biogeochemical cycling.
6)  ecological vicariances.
7)  modification in species behaviour.
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16.
1.  At 28°C conversion efficiency of total nitrogen (TN) was inversely related to size.
2.  In the pre-adult stage protein nitrogen (PN) conversion efficiency was high whereas in the Post-adult stage non-protein nitrogen (NPN) conversion efficiency was high.
3.  Lower temperature (20°C) was not congenial for PN conversion.
4.  Higher temperature favoured PN conversion for smaller fish but NPN for larger fish.
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17.
1.  Stimulation to left and right vagi caused an almost equal amount of inhibitory, and occasionally excitatory, effects on pacemaker activity. Both inhibitory and excitatory effects were abolished by atropine. Vagal stimulation hyperpolarized the resting membrane potential of pacemaker fibers in the sino-atrial valve, but did not change their action potential profile.
2.  The atrial action potential showed a prominent decrease in the action potential amplitude and duration in response to vagal stimulation. The atrial region surrounding the sino-atrial valve was more sensitive to right vagal stimulation.
3.  The fibers in the atrio-ventricular ring muscle were less sensitive to vagal stimulation than the atrial fibers. Some fibers showed a decrease in the action potential amplitude and duration by vagal stimulation, and other fibers showed a decrease in the amplitude, but a prolongation of the duration as the result of a slowing of the rate of upstroke. The atrial-ventricular conduction delay or block by vagal stimulation may depend on these properties of the action potential of the atrio-ventricular ring muscle.
4.  The sino-atrial conduction block is explained by the fact that the atrial fibers are more sensitive to vagal stimulation than pacemaker fibers.
5.  The possible pathways for the sino-ventricular conduction during vagal stimulation are discussed.
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18.
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19.
Müller  D. G.  Frenzer  K. 《Hydrobiologia》1993,(1):37-44
Culture studies with healthy and virus-infected isolates of Ectocarpus siliculosus, Feldmannia simplex and F. irregularis gave the following results:
–  Virus particles are produced in deformed reproductive organs (sporangia or gametangia) of the hosts and are released into the surrounding seawater.
–  Their infective potential is lost after several days of storage under laboratory conditions.
–  New infections occur when gametes or spores of the host get in contact with virus particles. The virus genome enters all cells of the developing new plant via mitosis.
–  Virus expression is variable, and in many cases the viability of the host is not impaired. Infected host plants may be partly fertile and pass the infection to their daughter plants.
–  Meiosis of the host can eliminate the virus genome and generate healthy progeny.
–  The genome of the Ectocarpus virus consists of dsDNA. Meiotic segregation patterns suggest an intimate association between virus genome and host chromosomes.
–  An extra-generic host range has been demonstrated for the Ectocarpus virus.
–  Field observations suggest that virus infections in ectocarpalean algae occur on all coasts of the world, and many or all Ectocarpus and Feldmannia populations are subject to contact with virus genomes.
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20.
1.  We used laser vibrometry and free field sound stimulation to study the frequency responses of the eardrum and the lateral body wall of awake male Eleutherodactylus coqui.
2.  The eardrum snowed one of two distinct frequency responses depending on whether the glottis was open (GO response) or closed (GC response) during the measurement.
3.  The lateral body wall vibrated with a maximum amplitude close to that of the eardrum and in the same frequency range.
4.  Covering the frog's body wall with vaseline reduced the vibration amplitude of the GC response by up to 15 dB.
5.  When a closed sound delivery system was used to stimulate a local area of the body wall the eardrum also showed one of two types of responses.
6.  These results suggest that sound is transmitted via the lung cavity to the internal surface of the eardrum. This lung input has a significant influence on the vibrations of the eardrum even when the glottis is closed.
7.  The vibration amplitude of the eardrum changed with the angle of sound incidence. The directionality was most pronounced in a narrow frequency range between the two main frequencies of the conspecific advertisement call.
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