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1.
1.  Tethered flies (Musca domestica) walking on an air-suspended ball show a spontaneous response to the e-vector of polarized light presented from above, i.e. a slowly rotating e-vector induces periodic changes in the flies' turning tendency. Suitable control experiments exclude the possibility that the response is elicited by intensity gradients in the stimulus (Figs. 1 and 2).
2.  Presence of the e-vector response in both white and UV light and its complete absence in yellow light equally support the concept that the specialized dorsal rim area of the compound eye with its highly polarization sensitive UV receptors R7marg and R8marg mediates polarization vision in flies (Fig. 3).
3.  E-vector orientations inducing no turning response additional to the fly's inherent turning tendency are either parallel (avoided e-vector) or perpendicular (preferred e-vector) to the animal's body axis (Figs. 1 and 4).
4.  Considering the fanlike arrangement of the microvillar orientations of R7marg and R8marg in the dorsal rim area of the eye of Calliphora and Musca, a stabilizing function of polarization vision in controlling the flight course is suggested and discussed in the context of results from other behavioural studies.
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2.
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   

3.
1.  The effects of potassium channel blockade on afferent axons and terminal regions in frog dorsal roots and spinal cords, respectively, were investigatedin vitro.
2.  A condition-test (C-T) protocol was used to assess the population relative refractory period. Characteristics of main axons were evaluated by stimulation at the proximal end of transected dorsal roots (DR). Characteristics of terminal regions were tested by stimulation at the base of the dorsal horn (DH).
3.  DH recovery of excitability was delayed by low concentrations of 4-aminopyridine (4-AP) and tetraethylammonium (TEA) alone or combined. The same treatments did not affect recovery to DR stimulation.
4.  DH recovery of excitability was not delayed by solutions suppressing terminal calcium influx.
5.  We conclude that sensitivity of the relative refractory period to potassium channel blocking agents differs between main axons and axon terminal regions. This may indicate differences between axon terminals and main axons in the mechanism of action potential repolarization.
6.  We hypothesize that rapid action potential repolarization by pharmacologically sensitive potassium channels in presynaptic terminal regions keeps terminal action potentials short. Terminal action potential brevity would limit calcium influx, thus preventing terminal calcium overload but contributing to transmission failures at spinal synapses.
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4.
1.  An extracellular recording and staining technique has been used to study the structure of individual ventral-cord elements in the auditory pathway ofLocusta migratoria.
2.  Three groups of auditory ventral-cord neurons can be distinguished: (a) neurons ascending to the supraesophageal ganglion, (b) T-shaped neurons, and (c) neurons limited to the thoracic ventral cord.
3.  The ventral-cord neurons ascending to the supraesophageal ganglion link the auditory centers of the thorax to those of the supraesophageal ganglion. These are, at least in part, richly arborized neurons of large diameter.
4.  The ventral-cord neurons with T structure send equivalent signals along both arms of the T; they resemble the neurons of the first group in that they make synaptic connections in the supraesophageal ganglion, but they also conduct auditory information to caudal regions of the thorax via the descending trunk of the axon.
5.  In the supraesophageal ganglion there are several extensive projection areas of the auditory ventral-cord neurons. No direct connections to the mushroom bodies, the central body or the protocerebral bridge could be demonstrated.
6.  The thoracic ventral-cord neurons act as short segmental interneurons, providing a connection between the tympanal receptor fibers and the ascending and T-shaped ventral-cord neurons. They play a crucial role in auditory information processing.
7.  The possible functional properties of the various morphological sections of the auditory ventral-cord neurons are discussed, with reference to their connections with motor and other neuronal systems.
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5.
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   

6.
1.  Paramecium bursaria was stimulated by a light spot of 10–15 m diameter, and the photosensitive site was searched by recording responses in swimming behavior and in membrane potential.
2.  Local stimulation to the anterior half of the cell caused an avoiding response.
3.  Stimulation to the cells deciliated by ethanol treatment elicited a depolarization of the membrane potential.
4.  Local stimulation to the anteroventral portion elicited a depolarization, but stimulation to the dorsal side induced no change in the membrane potential.
5.  The action spectrum of depolarization elicited by local stimulation to the anteroventral surface showed two main peaks at 420 nm and 560 nm, corresponding to those of light stimulation of the whole cell.
6.  It is concluded that a photosensitive site exists on the anteroventral surface ofParamecium, in particular within the oral groove of the cell. This local photosensitivity is discussed with respect to the mating reaction.
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7.
Oncostatin M, a multifunctional cytokine   总被引：6，自引：0，他引：6  
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8.
The circadian rhythm in the ERG amplitude of the lateral compound eye ofLimulus can be phase shifted either by general illumination or by illuminating combinations of the photoreceptor organs.
1.  For 15-min exposures, light confined to one lateral eye, or to the median ocelli, or to the ventral photoreceptor region resulted in the smallest phase shifts.
2.  Illuminating combinations of these organs produced larger shifts. The most effective combination tested included the median ocelli, the ventral photoreceptors, and one lateral eye. The phase shift resulting from illumination of this combination was only about one-half of the shift produced by general illumination.
3.  These results suggest that the circadian clock also receives light information from other, unidentified, photoreceptors located outside the prosoma.
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9.
Giles  N. 《Hydrobiologia》1994,(1):387-392
This paper reviews research results on food competition between a freshwater fish community and a breeding Tufted duck population. After the experimental removal of fish from the Main Lake, the following effects were observed:
(1)  1. Invertebrate (chironomid and gastropod) food for ducklings and adult Tufted ducks increased substantially.
(2)  2. Tufted duckling brood use of the lake increased greatly and Tufted duckling survival appears to have increased.
(3)  3. Shoveler and Pochard nested successfully for the first time.
(4)  4. Submerged aquatic macrophytes grew profusely over the lake bed for the first time leading directly to large increases in use of the Lake by wintering herbivorous waterfowl.
(5)  5. When fish were re-introduced to the Main Lake sampling bay the increases in invertebrate abundance and, to a less marked extent, macrophyte abundance were reversed.
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10.
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   

11.
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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12.
In this report we describe the most suitable protocol for callus formation and plant regeneration for cotton. We screened 15 cotton (Gossypium hirsutum L.) genotypes for metal resistance and two of them, Nazilli M-503 (M503) Nazilli 143 (N-143) selected as Cd, Cu and Ni resistant. The cotyledonary nodes from these genotypes were the best explants for regeneration of shoots (more than 90 %) and roots (50 to 70 %). Shoot apex also gave good shoot regeneration (more than 90 %) but their root regeneration efficiency was low (35 %). These results show that Murashige and Skoog (MS) media containing 0.44 μM naphthaleneacetic acid (NAA) and 0.98 μM indole-3-butyric acid (IBA) was the most suitable recipe for getting high shoot and root regeneration from cotyledonary nodes of N-143 and M503 cotton genotypes.Abbreviations
2,4 D  2,4-dichlorophenoxyacetic acid
BAP  6-benzylaminopurine
GA  gibberellic acid
IBA  indole-3-butyric acid
MS medium  Murashige and Skoog medium
NAA  naphthaleneacetic acid
This work was supported by the Textile Industry grant No. F000301 given to A.R. Memon.  相似文献   

13.
1.  Intracellular recordings from identified eye muscle motoneurons provide evidence that they are monosynaptically driven by the primary sensory axons from the thread hair receptors in the statocyst.
2.  The eye muscle motoneurons are either depolarized or actively hyperpolarized following irrigation of the Statocyst canals. The hyperpolarization of the motoneurons is brought about by the Statocyst receptors themselves either acting directly on the motoneurons or via inhibitory neurons.
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14.
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   

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.  If the eyes of young chickens are deprived of clear vision by translucent occluders, they develop considerable amounts of axial myopia within days. At the same time, the day time retinal dopamine levels drop by about 30%. Because the retinal dopamine levels of normally sighted chicks also differ diurnally and are low at night, we expected that the rate of axial eye growth might also differ during this time.
2.  Unexpectedly, eyes grew in length only during the day (about 0.13 mm/day) and even shrank during the night (about -0.04 mm/night, average net growth + 0.09 mm in 24 h).
3.  If the eyes were occluded, they grew both during the day and also at night (average net growth: + 0.16 mm in 24 h). Therefore, development of deprivation myopia was a result of the lack of growth inhibition at night rather than of excessive growth during the day when the actual deprivation occurred.
4.  Suppression of dopaminergic retinal pathways by intravitreal injections of the neurotoxin 6-hydroxy-dopamine (6-OHDA) also suppressed development of deprivation myopia and it restored the growth inhibition at night. With normal visual experience, the drug had no effect on axial eye growth and refractive state.
5.  Diurnal growth rhythms of the eyes disappeared under continuous light.
6.  Our results show that: (a) normal diurnal eye growth rhythms require a normal (12/12 h) light cycle and normal visual experience; with a degraded retinal image during the day, growth rates at night change so that they relate to retinal dopamine levels in the opposite way as with normal visual experience, (b) intact retinal dopaminergic pathways are necessary to mediate the deprivation-induced alterations in diurnal growth rhythms and myopia, (c) deprivation myopia is not simply a result of the lack of visual feedback control of eye growth during deprivation but rather of an active process related to abnormal diurnal dopamine rhythms.
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17.
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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18.
1.  We recorded compensatory eye stalk movements in response to pitch and roll stimulation of the visual, statocyst, and leg-proprioceptive systems in different species of crabs (Carcinus maenas, Heloecius cordiformis, Pachygrapsus marmoratus) (Fig. 2).
2.  The relative contribution of visual, statocyst and leg-proprioceptive inputs to eye stabilization in space varies greatly among different species (Fig. 3).
3.  We suggest that for stabilizing the eyes in space, the contribution of various sensory inputs in different species of crabs correspond to the availability of cues in their habitat. Semiterrestrial crabs living in a habitat with well defined and predictable visual geometry stabilize their eye stalks mainly by visual cues. Crabs living on solid substrate make strong use of leg proprioceptive input. Swimming crabs, and other predominantly aquatic crabs, rely mainly on their statocysts.
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19.
1.  The noninvasive techniques of intracellular optical physiology were used to measure reflectance changes in the deep pseudopupils of various regions of the apposition compound eyes of 3 species of stomatopod crustaceans.
2.  Upon exposure to light, prominent changes in reflectance were observed in all eye regions of all species studied. Generally, the response was an increasing reflectance following stimulus onset; however, in the lateral rows of the central ommatidial band of gonodactyloid stomatopods, the response was a rapid decrease in reflectance. Halftimes for the normal, increasing response were about 5 s in the gonodactyloid species and an order of magnitude longer in the squilloid species.
3.  The reflectance changes were probably produced by pupillary mechanisms similar to those previously described for insects. Evidence for this included the form and speed of the response, the observation that fluorescence from the visual pigment diminished with a similar time course to the increase in reflectance, and the tendency of the response to sensitize to repeated stimulation.
4.  Two spectral classes of photoreceptor were distinguishable in both the peripheral and central band regions of the eye. These classes were most sensitive to ultraviolet (360 nm) or long-wavelength (500 nm) light. The classes were distinguishable by the form and speed of the reflectance changes they produced when stimulated. Results of univariance experiments suggested that only these 2 classes existed in each eye region examined.
5.  In all species and ocular regions examined, the reflectance-change response operated over an intensity range of 3–4 orders of magnitude.
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20.
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