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1.
The foraging and echolocation behaviour of Myotis evotis was investigated during substrate-gleaning and aerial-hawking attacks. Bats gleaned moths from both the ground and a bark-covered trellis, however, they were equally adept at capturing flying moths. The calls emitted by M. evotis during substrate-gleaning sequences were short, broadband, and frequency-modulated (FM). Three behavioural phases were identified: search, hover, and attack. Gleaning search calls were significantly longer in duration, lower in highest frequency, and larger in bandwidth than hover/attack calls. Calls were detected in only 68% of gleaning sequences, and when they were emitted, bats ceased calling 200 ms before attacking. Terminal feeding buzzes, the rapid increase in pulse repetition rate associated with an attempted prey capture, were never recorded during gleaning attacks. The echolocation calls uttered by M. evotis during aerial-hawking foraging sequences were also short duration, high frequency, FM calls. Two distinct acoustic phases were identified: approach and terminal. Approach calls were significantly different from terminal calls in all variables measured. Calls were detected in 100% of aerial-hawking attacks and terminal feeding buzzes were invariably produced. Gleaning hover/attack calls were spectrally similar to aerial approach calls, but were shorter in duration and emitted at a significantly lower (but constant) repetition rate than aerial signals. Although the foraging environment (flight cage contents) remained unchanged between tasks (substrate-gleaning vs. aerial-hawking), bats emitted significantly lower amplitude calls while gleaning. We conclude that M. evotis adjusts its echolocation behaviour to meet the perceptual demands (acoustical constraints) imposed by each foraging situations.Abbreviations BW bandwidth - CF constant frequency - dB SPL decibels sound pressure level - FM frequency modulated - HF highest frequency - LF lowest frequency - PF peak frequency Presented at the meeting Acoustic Images in Bat Sonar, a conference on FM echolocation honoring Donald R. Griffin's contributions to experimental biology (June 14–16, Brown University, Providence RI).  相似文献   

2.
1.  Echolocating bats use the time delay between emitted sounds and returning echoes to determine the distance to an object. This study examined the accuracy of target ranging by bats and the effect of echo bandwidth on the bat's performance in a ranging task.
2.  Six big brown bats (Eptesicus fuscus) were trained in a yes-no procedure to discriminate between two phantom targets, one simulating a stationary target that reflected echoes at a fixed delay and another simulating a jittering target that reflected echoes undergoing small step-changes in delay.
3.  Eptesicus fuscus emits a frequency modulated sonar sound whose first harmonic sweeps from approximately 55 to 25 kHz in about 2 ms. Sound energy is also present in the second and third harmonics, contributing to a broadband signal in which each frequency in the sound can provide a time marker for its arrival at the bat's ears. We estimated range jitter discrimination in bats under conditions in which the echo information available to the bat was manipulated. Baseline performance with unfiltered echoes was compared to that with filtered echoes (low-pass filtered at 55 kHz and at 40 kHz; high-pass filtered at 40 kHz).
4.  The results indicate that the low-frequency portion of the first harmonic (25–40 kHz) is sufficient for the bat to discriminate echo delay changes of 0.4 microseconds. This echo delay discrimination corresponds to a distance discrimination of less than 0.07 mm.
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3.
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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4.
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   

5.
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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6.
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   

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.
1.  At ambient temperatures (T a) between 39 and 43°C, specimens of the waterproof treefrogChiromantis xerampelina, resting quietly in wind tunnels, adjust rates of evaporative water loss (EWL), maintaining body temperature (T b) 2–4°C belowT a.
2.  Brain heating and cooling, respectively, increased and decreased steady-state rates of thermoregulatory evaporative water loss (EWL), driving negative feedback changes inT b.
3.  Continuous infusions of epinephrine resulted in specific, dose-dependent, saturable increases in EWL; isoproterenol was more potent than epinephrine, which was more potent than phenylephrine. Tyramine injection also stimulated EWL.
4.  Non-specific increases in EWL stimulated by injections of cholinergic agonists were weakly antagonized by atropine, but thermally induced EWL, as well as adrenergically and cholinergically stimulated increases in EWL, were abolished by beta-adrenergic antagonists.
5.  Sweating decreased andT b increased during ganglionic blockade.
6.  The observations suggest thatC. xerampelina controls thermoregulatory EWL by modulating the sympathetic nervous outflow stimulating beta-adrenergic receptors on cutaneous mucous glands.
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9.
1.  When tested with legphone stimulation at 5 and 16 kHz, two prothoracic low-frequency neurons', ON1 and L1 of Acheta domesticus females, receive mainly excitation from one side (soma-ipsilateral in ON1, soma-contralateral in L1) and inhibition from the opposite side as is described for other cricket species (Figs. 2,3). While thresholds at 5 kHz are similar in L1 and ON1, L1 receives 16 kHz excitation with a 15- 20 dB higher threshold (lower than in other cricket species) than ON1. Stimulation of L1 with lower intensity 16 kHz sound on the side of its major input results in a clear IPSP visible in dendritic recordings (Figs. 3,4). In L1 and ON1 the intensity response at 16 kHz rises steeper than that at 5 kHz.
2.  The most sensitive auditory low-frequency receptors recorded have similar thresholds as ON1 and L1 at 5 kHz. Responses of the most sensitive auditory high-frequency receptors recorded show an intensity dependence which is similar to that of ON1 at 16 k Hz (Fig. 1C).
3.  Results of two-tone experiments show a tuning of inhibition in ON1 and L1 which is similar to excitatory tuning of ON1 (Fig. 4), however with about 10 to 15 dB higher thresholds. In contrast, in Gryllus bimaculatus an exact match between ON1-excitation and ON1/AN1 inhibition has been described.
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10.
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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11.
1.  Certain species of tiger moths emit clicks when stimulated by bat-like sounds. These clicks are generated by modified thoracic episterna (tymbals) (Fig. 1) and constitute a rhythmic behaviour activated by simple sensory input.
2.  Tymbal periods are indirectly related to stimulus intensity and periods (Fig. 3). Moths initiate sounds with the tymbal opposite to the stimulated ear and once a sequence commences it continues in an undisrupted fashion.
3.  The tymbal is innervated by a pleural branch (IIIN2a) of the metathoracic leg nerve, a similar anatomy to that in the unmodified episterna of silent moths (Fig. 5). Backfills of the IIIN2a in Cycnia tenera reveal sensory fibres and a cluster of 5–9 motor neurons with densely overlying dendritic fields (Fig. 6).
4.  Extracellular recordings of the IIIN2a reveal a large impulse preceding each tymbal sound (Fig. 7). I suggest that this impulse results from the synchronous firing of 2–3 motor neurons and is the motor output of the tymbal central pattern generator (CPG). The spikes alternate (Figs. 9, 10) and are bilaterally co-related (Fig. 11) but with an phase asymmetry of 2–3 ms (Fig. 12).
5.  Normal motor output continues in the absence of tymbal sounds (Fig. 13) and when all nerve-tymbal connections are severed (Fig. 14, Table 1) therefore this CPG operates independent of sensory feedback. A model is proposed for the tymbal circuitry based upon the present data and the auditory organization of related noctuid moths (Fig. 15). I propose that the tymbal response in modern arctiids evolved from either flight or walking CPGs and that preadaptive circuitry ancestral to tymbal movements still exists in modern silent Lepidoptera.
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12.
1.  Muscles of the posterior cardiac plate (pcp) and pyloric regions in the stomach of Squilla are innervated by motoneurons located in the stomatogastric ganglion (STG). The pattern of innervation of various muscles in these regions was determined using electrophysiological methods.
2.  The dilator muscles are singly or doubly innervated by the pyloric dilator neurons (PDs). The constrictor muscles are singly or doubly innervated by the pcp neuron (PCP) or the pyloric neurons (PYs). These muscles are sequentially activated by pcp-pyloric motor outputs produced by the PCP, PY, and PD. All muscles can generate an all-or-nothing spike.
3.  The constrictor muscles generate spikes followed by depolarizing afterpotentials which lead to a sustained depolarization with repetitive spikes. The PYs can entrain rhythmic spike discharges of these muscles.
4.  The spike of muscles remains unchanged by bath application of tetrodotoxin (10-7 M) to suppress neuronal impulse activities, but it is blocked by Mn2+ (10 mM).
5.  The constrictor muscle isolated from the STG displays an endogenous property of spontaneous membrane oscillation that produces a train of spikes. Brief depolarizing or hyperpolarizing stimuli can trigger or terminate an oscillatory potential, respectively, and reset the subsequent rhythm.
6.  The possible functions of myogenicity under the control of discharges of motoneurons in the pyloric constrictor neuromuscular system are discussed.
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13.
1.  The activity of tympanal high- and low-frequency receptors in the migratory locustLocusta migratoria was recorded with glass capillary microelectrodes, and Lucifer Yellow was then injected through the microelectrode to reveal the cells' metathoracic projections.
2.  A photodetector device was used to monitor the abdominal respiratory movements, which caused clearly visible deflections of the tympanal membrane.
3.  The auditory receptors respond not only to sound stimuli but also to the respiratory movements; these phasic (Figs. 1–3) or tonic (Fig. 4) responses are especially pronounced during the inspiration and expiration movements, and less so during the constriction phases.
4.  The magnitude of the response to sound depends on the phase of the stimulus with respect to the respiratory movements. At certain phases sound elicits no response at all (Fig. 5).
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14.
1.  The effect of intracellularly injected cAMP on the amplitude of excitatory postsynaptic potentials was studied using identified neurons of the snailHelix pomatia.
2.  In 25% of the experiments, postsynaptic cAMP elevation caused a pronounced augmentation of the excitatory postsynaptic potential (EPSP) amplitude, lasting up to 15–30 min.
3.  The results suggest that a cAMP increase in the postsynaptic neuron may be involved in the enhancement of synaptic efficiency.
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15.
1.  Rates of oxygen consumption were measured during locomotion in five species of marsupials of the family Dasyuridae. The body weights of the animals ranged between 0.15 and 1.12 kilograms.
2.  The rate of change of power input with speed was generally lower than equivalent eutherian values. The extrapolation to zero speed was consistently a higher multiple of resting metabolic levels than found in eutherians.
3.  The minimum cost of locomotion (M run) as a function of body mass (wt) is described by the equationM run=4.75 wt–0.34. The exponent is similar to that described for eutherians and reptiles, but the constant term is significantly lower.
4.  Metabolic scope in these animals is similar over the size range used and may be greater than in eutherians.
5.  Heat dissipation during locomotion has been partitioned into evaporative and non-evaporative routes. Storage of heat during locomotion was never more than fifty per cent of total production.
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16.
1.  Some units in the lateral ocellar nerves of the locust,Locusta migratoria, are influenced transsynaptically by the activity of ascending fibres in the thoracic connectives and therefore may be efferent to the afferent ocellar system.
2.  A variety of sensory inputs excite the ocellar nerve units, including illumination of the compound eyes, active and passive movement of the wings, wind stimuli to the thorax and sound.
3.  Most ocellar interneurons are influenced transsynaptically by electrical stimulation of the cervical connectives. L-neurons are depolarized and the components of their response to a rectangular light pulse are changed in amplitude. Only a few S-neurons could be examined. All of them were excited directly or indirectly.
4.  The descending ocellar interneurons (DN's) are influenced by stimulation of the contralateral connective, perhaps via efference to the ocellus or to ocellar L-cells.
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17.
1.  Maximal oxygen consumption rates ( [(V)\dot]\textO\text2 \dot V_{{\text{O}}_{\text{2}} } max; units, ml/g·h) were determined for four species of amphibians representing four families with habitat preferences varying from aquatic to terrestrial. Measured [(V)\dot]\textO\text2 \dot V_{{\text{O}}_{\text{2}} } max were:Xenopus laevis (aquatic), 1.33±0.16;Rana pipiens (semi-terrestrial), 0.54±0.10;Bufo cognatus (terrestrial), 1.91±0.26; andScaphiopus couchii (terrestrial), 1.91±0.26.
2.  In order to assess possible cardiovascular bases for these interspecific differences, heart rate increments (differences between resting and active heart rates) and ventricle weights were measured to evaluate differential cardiac outputs. In order to assess possible differential blood oxygen capacities, hematocrits and hemoglobin concentrations were measured. Blood volumes were determined to assess total blood oxygen storage capacities.
3.  Ventricle weights were statisticaly significantly different (p<0.01) between=" all=">B. cognatus>S. couchii>X. laevis>R. pipiens. These differences were closely positively correlated with the maximal metabolic rates of the species (Fig. 3a).
4.  There were no differences in heart rate increments between the four species (Fig. 2).
5.  Blood oxygen capacities were directly correlated with hemoglobin concentrations (Fig. 1). There were no interspecific differences in the amounts of oxygen bound per gram of hemoglobin (1.3 ml O2/g Hb). Blood oxygen capacities were significantly different in the following sequence;X. laevis >S. couchii andB. cognatus>R. pipiens.
6.  X. laevis had statistically significantly greater hematocrits than did the other three species.R. pipiens had significantly lower mean corpuscular hemoglobin concentrations.
7.  Blood volumes were statistically significantly different between all species examined,S. couchii>B. cognatus>X. laevis>R. pipiens.
8.  It is suggested that greater maximal oxygen consumption rates in anurans are correlated with 1) increased cardiac outputs based upon increased stroke volumes, 2) increased blood oxygen capacities due to either increased mean corpuscular hemoglobin concentration or increased hematocrit. Increased selective pressure for aerobic metabolism is also closely positively correlated with maximal blood oxygen storage capabilities.
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18.
1.  We tested the long-standing hypothesis that female frogs are attracted to the sound of a chorus of conspecific males from a distance. We studied the barking treefrog (Hyla gratiosa) because the location of choruses is unpredictable; thus, chorus sound indicates the presence of conspecific males as well as the location of a suitable breeding site.
2.  We measured the sound pressure level (SPL in dB re 20 Pa) in the 500 Hz octave band at various distances from choruses. The primary spectral peak in the advertisement call of this species is 400–500 Hz.
3.  The pattern of chorus sound attenuation in the 500 Hz band at two different sites was very similar and generally followed the pattern expected from geometrical spreading from a point source (Fig. 3). At one of the sites the SPL measured near ground level was always higher than that at a point 1 m above the ground (Fig. 3).
4.  Spectral analyses of the chorus sound at different distances showed that the low-frequency spectral peak in the range of 400–500 Hz was a prominent component, especially at 80–160 m (Figs. 1, 4). Amplitude peaks that corresponded to individual calls ofH. gratiosa and other species were also evident in oscillograms of recordings made at 160 m (Fig. 1).
5.  Gravid females oriented and moved toward a source of conspecific chorus sounds (originally recorded at 160 m from the pond) played back at 38–40 dB SPL in the 500 Hz octave band (Fig. 1, Table 1). Background noise levels were 43–47 dB SPL (C-weighted) and 24–25 dB SPL in the 500 Hz octave band.
6.  In a two-stimulus, choice experiment, females ofH. gratiosa always chose the source of a mixed chorus (H. gratiosa andH. cinerea) sound with conspecific males to a source of a pure chorus sound ofH. cinerea (Fig. 2, Table 2).
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19.
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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20.
1.  The activities of glycolytic enzymes and of related enzymes of anaerobic carbohydrate metabolism were determined inTubifex. The complete line of glycolytic enzymes was detected (Table 1). Only very little lactate dehydrogenase activity could be detected, while high activities of enzymes essential for the production of alanine and succinate are present.
2.  Under anaerobic conditions, lactate, alanine, succinate and volatile fatty acids are formed from14C-labeled glucose (Tables 2 and 3).
3.  Glycogen degradation was measured under anaerobic conditions (Fig. 1).
4.  During anaerobiosis a significant increase of alanine, succinate, propionate and acetate was found. However, the concentration of lactate increased only slightly. After an initial increase within the first 24 h of anaerobiosis, the concentration of alanine remained constant. Succinate, on the other hand, accumulated continuously during 48 h of anaerobiosis, reaching concentrations of 150 mol/g dry weight (Table 4, Fig. 2).
5.  The major end products of fermentation were identified as propionate and acetate. Both are excreted in substantial amounts (Table 5).
6.  The amount of anaerobic end products equals the amount of glycogen metabolized (Table 6).
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