Showing papers by "University of Stirling published in 1990"

Gorilla diet in the Lope Reserve, Gabon: A nutritional analysis

Abstract: The results of an analysis of gorilla diet in the Lope Reserve, Gabon are presented. Samples were assayed for nutrients and plant secondary compounds (total phenols, condensed tannins and alkaloids) in an attempt to explain gorilla food choice. The diet is the most diverse so far analysed for gorillas; it seems to be a balance between sugary fruit, proteinaceous leaves, and relatively fibrous stems. Most fruits and herbaceous stems are succulent, but some drier, fibrous fruit and bark is also consumed. Seeds are another component of the diet, including unripe ones. Fruit, seeds, leaves and bark may all contain very high levels of total phenols and condensed tannins; but all herbaceous stems assayed contain low levels of these compounds. Alkaloids are not apparently a significant component of gorilla foods, and may be avoided. Gorillas at Lope tend to avoid fatty fruit, and select leaves which are high in protein and low in fibre compared to the general vegetation. When fruit and preferred young leaves are scarce, proteinaceous barks and mature leaves, and sugary pith, are important sources of nutrients. We conclude that gorillas exploit the broad frugivore niche in West African lowland forests, and are part of the frugivore community there. What distinguishes them is their ability to eat large fibrous fruit, mature leaves and stems, and to overcome high levels of phenolics (we use “phenolics” as an umbrella term for both total phenols and condensed tannins). Gorilla diet at Lope overlaps greatly with that of sympatric, frugivorous, primates, and resembles more closely that of chimpanzees than it does gorilla diet studied elsewhere in Africa.

Factors Protecting Children Living in Disharmonious Homes: Maternal Reports

Abstract: This study investigated factors which were protective to children living in disharmonious homes. The sample was drawn from a representative sample of children aged 9 to 12 who took part in a previous general population study. Semi-structured interviews with both parents were used to assess the quality of the parental marriage. Mothers provided information on children's emotional and behavioral problems and putative protective factors. Fifty-seven families were in the disharmonious marriage group and 62 were in the harmonious marriage group. Putative protective factors, hypothesized to be beneficial for children, were either an aspect of social support or related to children's activities. Data were analyzed using a two-way analysis of variance with parental marriage and the putative protective factor as main effects. A differentiation was made between protective factors which interacted with parental marriage and those that acted independently. Factors which interacted with the quality of parental marriage were children having a relationship with an adult outside the family, an activity for which they received much positive recognition, and good sibling relationships. The parent-child relationship was associated with children's disturbance in both harmonious and disharmonious homes.

Composition of the diet of lowland gorillas at Lopé in Gabon

Abstract: This report describes the composition of the diet of lowland gorillas, Gorilla gorilla gorilla, at Lope in central Gabon. This population inhabits mature evergreen tropical forest and is not habituated to human observers. Data were collected during 6 years of an ongoing long-term study, from feeding-trails and by direct observation, but mostly by fecal analysis. Gorillas ate 182 plant foods from 134 species and 36 families. The fruit diet was diverse: 95 species were consumed, most with succulent pulp, and some immature seeds were eaten. Fruit remains were recorded in 98% of dung. Vegetative parts of Aframomum and Marantaceae formed staple foods, as they were abundant, accessible, and available year-round. Soil and social insects were also ingested; remains of weaver ants were recorded in one third of feces. More foods have been recorded for gorillas at Lope than elsewhere and this is the most frugivorous population studied so far.

Formal methods in human-computer interaction

Abstract: Preface Contributors 1. The role of formal methods in human-computer interaction Michael Harrison and Harold Thimbleby 2. HCI formalisms and cognitive psychology: the case of Task-Action Grammar Franz Schiele and Thomas Green 3. Putting design into practice: formal specification and the user interface Roger Took 4. Non-determinism as a paradigm for understanding the user interface Alan Dix 5. A state model of direct manipulation in interactive systems Michael Harrison and Alan Dix 6. Specification, analysis and refinement of interactive processes Bernard Sufrin and Jifeng He 7. From abstract models to functional prototypes Colin Runciman 8. Designing abstractions for communication control Gilbert Cockton 9. Structuring dialogues using CSP Heather Alexander Bibliography Index.

The conversion of linoleic acid and linolenic acid to longer chain polyunsaturated fatty acids by Tilapia (Oreochromis) nilotica in vivo.

Abstract: Tilapia (Oreochromis) nilotica were fed either a commercial diet containing 2.2% (n-3) and 0.5% (n-6) polyunsaturated fatty acids (PUFA), or a diet containing 1.0% methyl linoleate as the only PUFA. The fatty acid composition of tissue lipids generally reflected that of the diet. Fish from both dietary groups were injected intraperitoneally with 14C-labelled linoleic acid, 18:2 (n-6), or linolenic acid, 18:3 (n-3), and the distribution of radioactivity in tissue lipids examined. The conversion of both 18:2 (n-6) and 18:3 (n-3) to longer chain PUFA was lower in fish fed the commercial diet than in those fed the diet containing only 18:2 (n-6). Half of the radioactivity from both substrates recovered in liver polar lipids was present in C20 and C22 PUFA with fish maintained on the experimental diet. It is concluded that T. nilotica is capable of elongating and desaturating both 18:2 (n-6) and 18:3 (n-3), but that this conversion is suppressed by dietary longer chain PUFA.

The influence of cadmium, copper, lead, and zinc on the distribution and evolution of metallophytes in the British Isles.

Abstract: Mine spoils and other soils contaminated with cadmium, copper, lead and zinc show natural colonization by species which have strategies of avoidance or tolerance of metal toxicities. The distribution of plants on such substrata in the British Isles is examined in the light of present knowledge of such strategies. Evolutionary processes mediating the selection of tolerant individuals and ecotypic differentiation of adapted populations on metalliferous soils are considered. Other factors determining which species can and which cannot evolve tolerance include constitutional differences in species sensitivity to toxic metals, and phenotypic (environmentally-induced) tolerances. The importance of constitutional properties and phenotypic responses in providing explanations for plant distribution on metalliferous soils is assessed.

What Does it Mean to be Enterprising

Abstract: SUMMARY The last ten years in the U.K. have witnessed an acceleration of interest in enterprise education. The aims of enterprise education initiatives include helping people to start businesses; promoting awareness of enterprise; and creating the educational conditions for people to become more enterprising (Jamieson, 1984). This diversity of aims implies that enterprise is perceived differently by educationalists involved in enterprise education. This paper seeks to clarify the meaning of enterprise by exploring some key questions: 1Why is enterprise considered important? 2What insights are offered by enterprise education initiatives on the meaning of enterprise? 3How useful is a study of entrepreneurs for a study of enterprise? These questions dictate a need for further research to explore and clarify the meaning of enterprise. This is crucial for educationalists who wish to educate and assess enterprise as well as decide on the educational value of enterprise education. The relationship between enterprise competencies and small business owner management and employee competencies would be also clarified with an understanding of what it means to be enterprising.

Seasonal variation in lipid class and fatty acid composition of two small copepods in Balsfjorden, northern Norway

Abstract: Zooplankton were collected at Svartnes, northern Norway between 1985 and 1986. The lipid class and fatty acid composition of a subarctic population ofPseudocalanus acuspes (Giesbrecht, 1881) andAcartia longiremis Lilljeborg are described for four seasons of the year. The results are discussed in relation to the seasonal variation in abundance and dry weight of the predominant developmental stages. The lipid composition of these small copepod species resembles that of omnivorous or carnivorous species.P. acuspes andA. longiremis overwinter in a state of arrested development, but seem to feed actively throughout the year. This behaviour resembles that of the omnivoreMetridia longa (Lubbock), but is in contrast to that of the herbivoreCalanus finmarchicus (Gunnerus) from the same area, which spends the winter in diapause.

The biochemical composition of eggs from Macrobrachium rosenbergii in relation to embryonic development

Abstract: 1. 1. The proximate (water, protein, lipid, mineral ash) and elemental (carbon, nitrogen, phosphorus) composition of eggs of the freshwater prawn Macrobrachium rosenbergii (de Man, 1879) (Crustacea, Decapoda) were determined in relation to embryonic development. Eggs were sampled at four intervals during development, ranging from day 1 (newly spawned) to day 16 (about to hatch). 2. 2. Egg dry mass, lipid and carbon content all decreased during development as reserves were utilized; at the same time both water and mineral ash content increased. Although the mean content of both nitrogen and protein declined during development these were not statistically significant due to a high variance. Egg phosphorus content remained constant throughout development. 3. 3. In the lipid fraction triacylgycerol fatty acids provided the major fuel, although phospholipid was also utilized. The most important substrates were 16:0 and 18:1 fatty acids. 4. 4. There were strong suggestions of an initial increase in egg lipid content during the first 5 days of development, though this was not statistically significant and the source of the extra material is unknown.

The histopathology associated with the juvenile stages of Lepeophtheirus salmonis on the Atlantic salmon, Salmo salar L.

Abstract: . Atlantic salmon infected with juvenile stages of Lepeophtheirus salmonis were obtained from sea loch cage sites on the West coast of Scotland. Attached parasites on the skin were studied using light and electron microscopy. Behavioural activity was observed in attached stages maintained on skin in vitro. Pathological changes were associated with four main areas of interaction between the parasite and the host, namely second antennal attachment, filament attachment, maxilliped activity and feeding activity. The skin changes involved were initial mechanical disruption followed by epidermal hyperplasia. The filament material was secreted into the epidermis and spread laterally without breaching the basement membrane. Surprisingly little reaction to the filament occurred, but chalimus activity resulted in chronic changes which were more marked as the later chalimus stages were reached. Fibroplasia was a feature of lesions induced by redundant filaments resulting in small nodular lesions. After erosion of these nodules, all that remained were the melanized rings characteristic of old chalimus sites.

Soil variation with altitude on Volcan Barva, Costa Rica.

Abstract: Summary Soils were examined from each of six primary forest plots at altitudes of 100 m, 500 m, 1000 m, 1500 m, 2000 m and 2600 m on Volcan Barva, Costa Rica. All were on volcanic parent materials. There was evidence of decreasing intensity of weathering and organic matter decomposition with increasing altitude. Subsoil clay content decreased from 80% at 100 m altitude to less than 10% at 2000 m. Ratios of free to total iron decreased from 0.3 to less than 0.1. Organic matter in the surface horizons increased from 18% to 49% over the same altitude range. The uppermost site at 2600 m was formed on younger and less weathered material and had greater concentrations of exchangeable bases than all the other sites. There was no evidence that the nutrients measured were less well supplied at high altitudes, and forest changes with altitude were not caused by any soil changes examined in this study.

Eating disorders, perceived control, assertiveness and hostility.

Abstract: There are anecdotal claims that eating disorder patients perceive themselves as highly controlled by the family and by society, but that they do not show assertive behaviour towards controllers. Anorexic and bulimic females were compared with female psychiatric patients, dieters and non-dieting controls on measures of eating disorder symptomatology, locus of control, assertiveness, inwardly directed hostility, family control and family encouragement of independence. Eating disorder patients reported significantly more external control, more inwardly directed hostility, less self-assertion and less family encouragement of independence than dieters and non-dieting controls, but they did not differ from psychiatric controls. Most of the characteristics seen in eating disorder subjects were also reported by psychiatric controls.

Invitations to Responsibility

Abstract: In this chapter, I will describe a model of engagement for working with adolescent boys and young men1 who have sexually abused. The practice of engagement concerns assisting young men to find motivation to discover their own preferences and capacities for respectful ways of being and relating. It involves processes for inviting adolescents to cease abusive practices by choosing to undertake and invest in a journey toward responsibility and respect of self and others. A detailed description of theory and practice concerning the application of this model to adult men who abuse has been previously documented (Jenkins, 1990). This chapter concerns specific developments and applications of the model for young men.

Joint visual attention, manual pointing, and preverbal communication in human infancy.

Abstract: In the world of the prelinguistic infant an adult's direction of gaze exerts a powerful effect in redirecting the infant's visual attention. The adult's behaviour serves to signal potentially interesting objects and events to the baby. Our experiments suggest that three cognitive mechanisms are implicated in the comprehension of the adult's head and eye movements between 6 and 18 months. These we call the "ecological," the "geometric," and the "representational" mechanisms of looking where someone else is looking. This chapter explores the relationship in development between the signalling function of joint visual attention and the infant's comprehension and production of manual pointing.

Preliminary studies on forest structure and floristics on Volcán Barva, Costa Rica

Abstract: Volcan Barva, Costa Rica, has on its northern slope an unbroken sequence of rain forest on volcanic parent materials from near sea level at La Selva Field Station up to its summit at 2906 m. It provides a good area to study forest changes with altitude and their causes. In the present paper we describe the forests as a background for soil and litterfall studies from 1 ha plots at each of the following altitudes: 100 m, 500 m, 1000 m, 1500 m, 2000 m and 2600 m. The canopy heights (with height of the highest emergent in parentheses) ranged from 35–40 m (45 m) at 100 m to 20–23 m (32 m) at 2600 m; basal area was least (22.7 m2) at 100 m and highest (51.2 m2) at 2600 m; the tree (≥10 cm dbh) density ranged from 391 ha–1at 500 m to 617 ha–1 at 2600 m. Most trees were identified and on samples of them we recorded presence of buttresses, lianes, skiophytic climbers, vascular epiphytes and bryophytes; and drew profile diagrams. In the classification of Whitmore (1984) the two lower plots are evergreen lowland rain forests; the other four are lower montane rain forest. Species richness was highest in the plot at 500 m, with at least 135 species of tree, and least at 2600 m, with at least 35 species. The Volcan Barva forest altitudinal sequence is briefly compared with those elsewhere.

Air to air recouperator

Abstract: heat recouperator having a rotary wheel heat exchanger uses a random matrix media comprising a plurality o~ small diameter heat-retentive fibrous material, which provides high thermal efficiency in exchanging heat between inlet and exhaust air streams.

Brief threatening events beneficial for captive tamarins

Abstract: To evaluate speculation indirectly suggesting that brief arousal may be beneficial to animals, 39 cotton-top tamarins (Saguinus oedipus) living in 4 large families were observed (a) after normal husbandry procedures that excite them (capture and brief removal of infants or older monkeys), (b) after exposure to an over-flying bird model, and (c) compared with control days in which neither of the above occurred. Both arousal conditions caused a decrease in play and locomotion, and an increase in grooming and contact during the remainder of the day. These behavioral changes are similar to the patterns reported as positive effects of enrichment but are dissimilar to negative effects of long-term stressors reported. The pattern of changes in studies of enrichment and of stress enables more objective evaluation of ambiguous events.

Seasonal, hydrological, and land management factors controlling dissolved organic carbon concentrations in the loch fleet catchments, Southwest Scotland

Abstract: Dissolved organic carbon (DOC) was measured at hourly or two-hourly intervals during more than 30 events in one forested and two moorland subcatchments of the Loch Fleet catchment in southwest Scotland. The dominantly peaty soils in the catchments resulted in small discharge-related DOC variations within individual events, with a maximum range of about 2 mg 1−1. Seasonal variations were larger with an amplitude of 8-9 mg 1−1 and maximum concentrations in the summer months. The forested stream had the highest mean DOC, twice as large as the comparable moorland stream in the preliming phase. Applications of lime to the catchments increased stream DOC concentrations, with the largest increases in the moorland catchments.

Fecundity, egg size and total egg volume differences in 12 stocks of rainbow trout, Oncorhynchus mykiss Richardson

Abstract: . Measurements of egg number, egg size and total egg volume in relation to post-stripped weight, made on the eggs stripped from 12 separately maintained farm stocks of 4-year-old rainbow trout. Oncorhynchus mykiss Richardson, revealed highly significant differences between populations when analysed by regression and covariance statistical techniques. All of the stocks showed increases in fecundity with increasing fish size, with 61% (coefficient of determination or r2) of the variation in fecundity of the 12 stocks explained by the common regression on parental fish size. Comparison of the regressions of the different stocks revealed that the rate of increase of fecundity with increasing fish weight was constant throughout the weight range (i.e. the regressions had similar slopes) although there were highly significant differences in elevation, with some stocks producing almost twice as many eggs as some of the others. By contrast, the relationship of egg size with fish weight was much more variable with three of the stocks showing no significant regression of egg size on fish weight and a further two stocks with data poorly fitted to the regressions. Of the remaining seven stocks only one showed a significant difference in slope of the regression with modest increases in fish weight being associated with large increases in egg size. Only four of the remaining stocks of fish showed significant differences in the elevation of their regressions, i.e. the egg sizes were significantly different after the potentially conflicting influence of fish size was partitioned using covariance techniques. Assessments of total egg volume produced far improved regressions on post-strip weight with 75% (r2) of the variation in the pooled data of the 12 stocks being described by the line of the common regression. In general, there appeared to be a “trade-off” between egg number and size with the most and least fecund fish producing somewhat smaller and larger eggs respectively. All 12 regressions of totai egg volume on fish weight showed a common slope. However, there were significant differences in elevation of the regressions, with some of the stocks of trout producing up to a 55% greater volume of eggs. There appeared to be no relationship between the differences in egg number, size or total egg volume and the type or geograpfiical location of the farms on which the stocks were held. Although it remains to be determined to what extent these differences in reproductive performance are Inheritable, it is recommended that these characteristics should be taken into account by hatcheries in tbe design of long-term broodstock selection programmes for rainbow trout.

Incorporation into Phospholipid Classes and Metabolism via Desaturation and Elongation of Various 14C‐Labelled (n‐3) and (n‐6) Polyunsaturated Fatty Acids in Trout Astrocytes in Primary Culture

Abstract: The incorporation and metabolism of [1-14C]18:3(n-3), [1-14C]20:5(n-3), [1-14C]18:2(n-6), and [1-14C]20:4(n-6) were studied in primary cultures of trout brain astrocytes. There were no significant differences between the amounts of individual fatty acids incorporated into total lipid at 22 degrees C, with greater than 90% of all the fatty acids being incorporated into polar lipid classes. The distributions of 18:2(n-6), 18:3(n-3), and 20:5(n-3) in individual phospholipid classes at 22 degrees C were very similar, with 57-63 and 18-24% being incorporated into phosphatidylcholine and phosphatidylethanolamine, respectively. Approximately equal amounts of 20:4(n-6), approximately 30% of the total, were incorporated into each of phosphatidylcholine, phosphatidylethanolamine, and phosphatidylinositol. The metabolism of the (n-3) fatty acids to longer-chain and more unsaturated species was significantly greater than that of (n-6) acids, but delta 4-desaturase activity was very low. A culture temperature of 10 degrees C increased the incorporation of all the fatty acids into total lipid and that of C20 fatty acids into polar lipid. At 10 degrees C, the incorporation of C20 fatty acids into phosphatidylethanolamine and phosphatidylinositol was increased, and the incorporation into phosphatidylcholine and phosphatidylserine was decreased. The distribution of C18 fatty acids was unchanged at the lower temperature, as was the desaturation and elongation of all the polyunsaturated fatty acids incorporated.

Food-sharing in cotton-top tamarins (Saguinus oedipus).

Abstract: Food-sharing behaviour was observed in 9 captive families of cotton-top tamarins (range 4–14 individuals per group), during meals of fresh fruit. Food was transferred to infants by their parents and older sibs in response to begging, and was also offered to them without prior solicitation. Older, mature, reproductively suppressed individuals shared more than young immature monkeys. Infants in larger families received more food than those in smaller ones, though individuals in smaller families shared more. Transfer to infants increased to a maximum at 12 weeks of age and then declined gradually. At one year of age they no longer received food from others. Food sharing by older siblings is a form of helping behaviour which may increase their inclusive fitness, and benefit parents, both directly, by reducing the costs they incur in rearing young, and indirectly, by increasing the amount of food available to infants.