Showing papers by "University of Stirling published in 1979"

Mating patterns and reproductive strategies in a community of wild chimpanzees (Pan troglodytes schweinfurthii)

Abstract: 1. The sexual behaviour of a chimpanzee community in the Gombe National Park, Tanzania, was studied intensively for 16 months. Additional information came from 15 years of demographic and behavioural data accumulated by Jane Goodall and members of the Gombe Stream Research Centre. 2. The mating system of the Gombe chimpanzees is flexible and comprises three distinct mating patterns: (a) opportunistic, non-competitive mating, when an oestrous female may be mated by all the community males; (b) possessiveness, when a male forms a special short-term relationship with an oestrous female and may prevent lower-ranking males from copulating with her; and (c) consortships, when a male and a female leave the group and remain alone, actively avoiding other chimpanzees. While males took the initiative in possessive behaviour and consortships, females had to cooperate for a successful relationship to develop. 3. Data from 14 conceptions indicated that the majority of females (9) became pregnant while participating in the restrictive mating patterns, possessiveness and consorting. It could be established definitely that seven of these females were consorting during the cycle in which they conceived. As 73% of the 1137 observed copulations occurred during opportunistic mating, 25% during possessiveness, and only 2% during consortships, there was no correlation between copulation frequency and reproductive success. 4. Adult males showed differential frequencies of participation in the restrictive mating patterns. Male age, dominance rank, and the amount of agonistic behaviour directed to females showed no correlation with participation in the restrictive mating patterns. The following male characteristics did show significant, positive correlations with involvement in the restrictive mating patterns: (a) the amount of time spent in the same group as oestrous females, (b) the proportion of that time spent grooming oestrous females in groups, and (c) the frequency with which males shared food with females. While dominance ranks of the adult males showed no consistent correlation with involvement in the restrictive mating patterns, it was clear that the most dominant male did gain an advantage. He was the only male able to monopolise oestrous females by showing possessive behaviour. 5. Consortships appeared to be the optimal reproductive strategy for males (with the exception of the most dominant) and females, as they gave males the highest probability of reproductive success, and allowed females to exercise choice. However, there appeared to be disadvantages associated with consort formation; the greatest of these was the increased risk of intercommunity encounters. While all individuals have the potential to practice each mating pattern, the strategy actually used at any moment will be determined by variables both within the individual, e.g. age, physical condition, dominance position; and by social factors in the group, e.g. general stability of male dominance relationships, presence of a strong alpha male, existence of special male-female relationships.

The role of melano‐macrophage centres in iron storage in normal and diseased fish

Abstract: . The spleen, kidney and liver melano-macrophage centres of 14 species of clinically normal teleost fish were examined histochemically for ferric iron. Iron was present in varying amounts within the splenic centres of most specimens, but by contrast it was rarely found in the centres of the kidney and the liver. Under conditions of starvation and in diseased fish, a markedly increased deposition of ferric iron occurred in the splenic centres of nearly all fish examined. By comparison, the iron content in the kidney and liver centres was generally still very low. These results suggest that there exist important functional differences between the pigment centres of different haemopoietic tissues of teleosts.

Learning when reward is delayed: a marking hypothesis.

Abstract: Rats were trained on spatial discriminations in which reward was delayed for 1 min. Experiment 1 tested Lett's hypothesis that responses made in the home cage during the delay interval are less likely to interfere with learning than responses made in the maze. Experimental subjects were transferred to their home cages during the delay interval, and control subjects were picked up but then immediately replaced in the maze. Contrary to Lett's hypothesis, both groups learned. Further experiments suggested that handling following a choice response was the crucial variable in producing learning: No learning occurred when handling was delayed (Experiment 2) or omitted (Experiment 3). One possible explanation for the fact that handling facilitated learning is that it served to mark the preceding choice response in memory so that subjects were then more likely to recall it when subsequently reinforced. In accordance with this interpretation, learning was found to be just as strong when the choice response was followed by an intense light or noise as by handling (Experiment 4). The implication of marking for other phenomena such as avoidance, quasi-reinforcement, and the paradoxical effects of punishment is also discussed.

Nephrocalcinosis in rainbow trout Salmo gairdneri Richardson; the effect of exposure to elevated CO2 concentrations

Abstract: . Rainbow trout exposed to environmental free C02 concentrations ranging from 12–60 mg/1 for a minimum of 275 days developed nephrocalcinosis. Gross, histopathological and chemical examinations demonstrated that prevalence and severity of nephrocalcinosis increased with increasing CO2 concentrations. The condition was characterized by calcification and granuloma formation in kidney and stomach. Diet, but not water, PO4 -P concentration appeared to modify the prevalence and severity at each CO2 concentration tested.

Energetics of growth in House martins (Delichon urbica)

Abstract: Energy requirements for growth and maintenance of nestling House martins was studied in relation to brood size and age. Parallel studies of feeding rates and faecal output were made. The effect of mutual insulation between members of the brood on metabolism was of significance for reducing maintenance energy requirements. Of great value for predicting the peak energy demand of the brood was the number of young and their individual requirements for growth and maintenance at different ages. Power equations are given for predicting brood assimilation, faecal output and feeding frequency in relation to brood size. The impact of food scarcity on growth patterns was assessed. The large lipid stores of nestlings served as an energy reserve during adverse conditions both before and after fledging. Asynchronous hatching in large broods is interpreted as a mechanism which serves to minimize the peak in energy demand which occurs about 12 days after the brood hatches.

Spermine, spermidine and putrescine in fungal development.

Abstract: Publisher Summary A number of different naturally-occurring oligoamines exist but only three are known to be widely distributed—namely, putrescine (1,4-diaminobutane), spermidine (4 azaoctane- 1,8-diamine), and spermine (4,9 diazadodecane-l,12-diamine). Because there is a correlation among oligoamine synthesis, cell growth, and differentiation and as the latter process cannot be easily studied in bacteria, fungi have a number of advantages in studying differentiation. Fungi exhibit a wide variety of developmental patterns many of which can be varied under laboratory conditions. Also, extensive genetic analysis can often be carried out on fungi. They are suitable phyllum for studying the role of oligoamines in development, and this helps to solve the more general question of oligoamine function. The chapter discusses the distribution and biosynthesis of oligoamines with particular emphasis on the contrast between prokaryotes and eukaryotes. Oligoamine distribution and synthesis in fungi, and related amino-acid biosynthesis is presented. Fungal development, with emphasis on correlations among nucleic acid, protein, and oligoamine synthesis, is also discussed.

Host parasite interactions between Ichthyobodo necator (Henneguy 1883) and farmed Salmonids

Abstract: . The prevalence and intensity of Ichtyobodo necator infestations on farmed salmonids was investigated over a 7-month period. The infestations were found to be markedly age dependent. Ichtyobodo infestations peaked at 4 weeks after commencement of first feeding and mortalities peaked at 4 6% per week at 8 weeks in the 0+ fish. Both infestations and mortalities showed a marked decline to zero shortly after these periods with no chemotherapy. No Ichtyobodo were seen on the 1+ fish until late in the study after a drop in temperature to below 10°C, when they reappeared on the 0+fish also. Ichtyobodo were found at temperatures between 3–5°C and 16°C and in the 0+fish appeared irrespective of the condition of the fish. It is suggested that some form of host defence mechanism is operating which limits the Ichtyobodo infestations in farmed salmonids.

Possible role of volatile Fatty acids and abscisic Acid in the dormancy of oats.

Abstract: Species of Avena differ markedly in their levels of pre- and post-harvest dormancy. These species offer the opportunity of determining if dormancy is related to the endogenous level of growth inhibitor. Germinability in two species of differing levels of dormancy, common oat Avena sativa L., and wild oat Avena fatua L. was assessed as were the contents of abscisic acid and volatile fatty acids of chain length C6-C10. In A. sativa which did not possess postharvest dormancy there was no correlation between germination and inhibitor levels but in A. fatua the relationship between the content of fatty acid and dormancy was good. The loss of these fatty acids in dry storage by evaporation could explain after ripening.

The pathology and histopathology of nephrocalcinosis in rainbow trout Salmo gairdneri Richardson in fresh water

Abstract: . A detailed histopathological study of naturally occurring and experimentally induced outbreaks of nephrocalcinosis was carried out on rainbow trout from a number of farms. Histopathological effects were confined to the kidney, stomach and skeletal muscle. Lesions of the stomach wall were often found in the absence of renal lesions but muscle lesions were only found in the presence of severe renal damage. It was considered that the calcification was the result of deposition of calcium salts within necrotic tissue, and thus was dystrophic rather than metastatic. Variation between farms was considered to be due to variations in the effects of different aetiological factors in the complex series of physico-chemical events which appear to induce the condition.

Stomata and plasmodesmata

Abstract: In developing epidermal tissue ofPhaseolus vulgare L. complete plasmodesmatal connections occurred between guard cells and epidermal cells and between sister guard cells of a stoma but they were not seen in fully differentiated tissue. However, incomplete, aborted plasmodesmata were occasionally seen in the common guard/epidermal cell wall, usually connected to the epidermal cell protoplast, in mature tissue. Plasmodesmatal connections between neighbouring epidermal cells were commonly observed in tissue at all stages of development. In all locations, the plasmodesmata were usually unbranched occurring singly or in small pit fields; very rarely branched, incomplete plasmodesmata were also seen in the wall between mature guard and epidermal cells. The significance of these findings were related to stomatal functioning and to the development of plasmodesmata in general.

Models and Measures of Mental Workload

Abstract: At the meeting on Monitoring Behaviour and Supervisory Control held in Berchtesgarten in 1976, someone made the point that we possess a very large body of knowledge about human performance and how to measure it, and yet we are still unable to put it to efficient use in designing man-machine systems. Surely, he said, it should be possible to find a unifying theory which would tie it all together in a useful way.

Temporal variation in benthic ciliates and the application of association analysis

Abstract: SUMMARY. A 2-year sampling programme of three benthic sites in a small eutrophic loch revealed large communities of ciliated protozoa consisting of a wide diversity of species (91 spp. over the 2 years). Species-groups described with the aid of association analysis (normal and inverse) indicated the existence of a ‘ubiquitous’ species-group consisting of at least Cyclidium glaucoma and Aspidisca costata. Another species-group containing large ciliates (Loxodes striatus, Frontonia leucas, Spirostomum spp. and Paramecium spp.) was characteristic of the summer months at all sites. It is advocated that association analysis might increase the value of protozoa as pollution indicators.

Pansteatitis in rainbow trout Salmo gairdneri Richardson: a clinical and histopathological study

Abstract: Pansteatitis is a nutritionally mediated condition associated with the feeding of certain types of fish oil or unsaturated fatty acids of fish origin in a diet poor in vitamin E It occurs regularly in mink, cats, pigs and poultry, all of which are fed on high fish diets, but this is the first description of the condition from cultured fish The main presenting signs in affected rainbow trout were swimming aberrations, discolouration and high mortality after minimal stress Gross postmortem features were restricted to changes in the liver and swimbladder but, at the microscopic level, histopathological changes involving inflammatory cellular infiltration of lipid tissue in swimbladder, abdominal and peripancreatic fat and hypodermis, accompanied by myopathic changes, were regularly observed

Changes in serum parameters of Saprolegnia-infected brown trout, Salmo trutta L.

Abstract: Fungal infection of both wild and hatchery-reared sexually mature brown trout, Salmo trutta L, was caused by Saprolegnia diclina Humphrey Type 1 The major ions in the serum of infected fish were all significantly reduced in concentration and it is suggested that the primary cause of death was osmoregulatory breakdown resulting in a lethal haemodilution Severe hypoproteinaemia and a significant reduction in the albumin/globulin ratio were reflected in the electro-phoretogram of the serum proteins from infected fish

Pressure and Solute Potentials in Stomatal Cells of Tradescantia virginiana

Abstract: The postulated mechanical advantage of subsidiary cells over guard cells has been estimated using leaves of Tradescantia virginiana The turgor pressures of subsidiary cells were adjusted to be zero or maxima! by plasmolytic treatments, and the resulting stomatal apertures were measured The 'mechanical advantage' was calculated from two mathematical models which define it as an 'antagonism ratio' The discussion deals with methods of preparing the tissue, the validity of the plasmolytic treatments, and the function of the antagonism ratio in relation to the Spannungsphase

Exhaust gas recirculation apparatus

Abstract: Apparatus for recirculating combustion exhaust gases to the burner region of a Stirling cycle hot-gas engine to lower combustion temperature and reduct NO x formation includes a first wall separating the exhaust gas stream from the inlet air stream, a second wall separating the exhaust gas stream from the burner region, and low flow resistance ejectors formed in the first and second walls for admitting the inlet air to the burner region and for entraining and mixing with the inlet air portion of the exhaust gas stream. In a preferred embodiment the ejectors are arranged around the periphery of a cylindrical burner region and oriented to admit the air/exhaust gas mixture tangentially to promote mixing. In another preferred embodiment a single annular ejector surrounds and feeds the air/exhaust gas mixture to a cylindrical burner region. The annular ejector includes an annular plate with radially-directed flow passages to provide an even distribution of the air/exhaust gas mixture to the burner region.

Simple drawing and pattern completion techniques for studying visualization and long-term visual knowledge

Abstract: Simple and efficient drawing and completion tasks for studying visual memory are developed. In Experiment I subjects reproduced a series of matrix patterns by filling empty matrices. The serial position function was fiat, except that accuracy was much higher for final patterns. In Experiment 2 this recency effect was removed by an interpolated pattern classification task. Experiments 3 and 4 examined the effect of counting backward during intervals of from 3 to 15 sec on the recall of single patterns. Drawings were much less accurate after filled intervals but the duration of the interval had no effect. Experiment 5 tested retention of series of patterns using a completion task. On immediate test the serial position function was the same as in Experiments 1 and 2. On a final test accuracy was unchanged except for final items, which then showed a small negative recency effect. It is argued that performance is so similar in the drawing, completion, and previously reported recognition tasks because in all it is based upon the use of general-purpose knowledge accessible to voluntary processing. Visualization in these tasks is analogous to but different from verbal STM. One main difference is that there is no sign of temporary storage of visualized information after attention has turned to other things.

Inhibition of fungi by gallic acid in relation to growth on leaves and litter

Abstract: Gallic acid was inhibitory to many fungi from leaves and soil. Notable exceptions included some Penicillium spp. which grew in solutions containing the acid as a sole source of carbon. Inhibition was correlated with polyphenoloxidase activity and the accumulation of the products of incomplete oxidation in the medium. These products had no effect on Penicillium spp. Several substances from the oxidation of the acid by two fungi have been separated and described. Most of these were inhibitory and in some cases toxic in bioassay tests. Two at least were relatively stable and were only slowly broken down by two bacterium species. Stable substances such as these may play an important role in restricting growth of some species of fungi on leaves and in litter containing the acid. Decomposition of this type of litter may be restricted to tolerant fungi such as some Penicillium spp.

Occlusable Yellow Corneas in Tetraodontidae

Abstract: In three species of brackish-water puffer fish (Tetraodontidae) the corneas are colourless in the dark but become yellow in the light, through the migration of pigment in chromatophore cells lining the corneal margins. Spectrophotometry indicted the pigment to be a carotenoid. The threshold and time course of pigment migration ware determined, and the effects of Unilateral illumination and optic nerve section suggest that the movement is under local control. It is shown that the increase in optical sensitivity obtained by clearing the eye of pigment should be advantageous for fish living in clear water.

Some effects of salinity and temperature on the osmotic and ionic regulation of Praunus flexuosus (Crustacea, Mysidacea) from Isefjord

Abstract: The salinity tolerance, osmotic regulation and ionic regulation of the mysid crustacean, Praunus flexuosus, collected at the Isefjord, Denmark, has been investigated over a range of salinities, and at temperatures from 5 to 20 °c for both winter and summer animals. Survival at low salinities was enhanced when the animals were kept at low temperatures, and this enhancement was especially pronounced in animals collected in winter. A clear pattern of hyper/hypo-osmotic regulation was found, but no effect of season or temperature on the osmotic concentration was observed. The blood concentration of Isefjord animals was significantly lower at any given salinity than that of previously srudied animals from Loch Etive, Scotland. This reduction is considered to be due to long-term acclimation, and the findings are compared with other crustacea where studies have been made on distinct populations. The blood concentrations of sodium, potassium, calcium, magnesium and chloride were determined at three salin...

Mass mortalities in silver carp Hypophthalmichthys molitrix (Valenciennes) associated with bacterial infection following handling

Abstract: . Mass mortalities in silver carp were related to infection of handling lesions with Proteus rettgeri, a gram negative bacterium normally found in the gut of poultry. Poultry faeces are used extensively to fertilize carp ponds and experimental infections showed that the condition could be reproduced by scarification and exposure to the micro-organism or by its inoculation.