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41.
42.
Using the Irish Sea area as a case-study, we argue that both sites and landscapes can be understood as containing a series of components procured from the landscape and from human, animal, and object bodies. These components were organized in a way that commented on and related to specific cultural relationships between these different locations and through the substances found within them. This idea is explored by examining Neolithic monuments, material culture, and natural materials in southwest Wales, northwest Wales, the Isle of Man, and southwest Scotland. We trace some metaphorical schemes which were integral to Neolithic activity in this part of the Irish Sea. In particular, we highlight the metaphorical connections between water and stone in places associated with transformation, particularly the repeated transformation of human bodies. We suggest that the series of associations present in the Neolithic were not invested with a uniform meaning but, instead, were polyvalent, subject to conflicting interpretations, contextually specific and variable through both space and time. The relationship between these elements was therefore dependent on the contexts of their association. Nevertheless, the association of water and stone can be found repeatedly throughout the Neolithic world and may have been the medium of a powerful trope within broader conceptions of the world. This article is intended as a preliminary consideration of these issues (particularly the links between stone, mountains, water, quartz, shell, and human remains) and is offered as a thinking-point for ongoing research in this area. 相似文献
43.
P. J. GOODSELL M. J. FOWLER‐WALKER B. M. GILLANDERS S. D. CONNELL 《Austral ecology》2004,29(3):350-357
Abstract The ecology of Australia's most extensive canopy‐forming alga, Ecklonia radiata, is often studied with little regard as to whether it occurs in monospecific stands or as part of a mixed assemblage of canopy‐forming algae. We tested the hypothesis that E. radiata does not primarily occur as monospecific stands, rather it occurs more often in stands of mixed algae. At a 1‐m2 scale we recognized three main configurations within forests of algae (hereafter called stands): E. radiata that occurs as (i) monospecific stands; (ii) clumps (four or more individuals together) surrounded by species of Fucales; or (iii) individual plants (or clusters of fewer than three plants) interspersed among species of Fucales. All three types of stand occurred in similar proportions (percentage cover) across two regions of Australia's southern coastline (Western and South Australia). We also tested the hypothesis that these three types of stands (identified at 1 m2) contain different assemblages of invertebrates associated with the holdfast of E. radiata. Assemblages of invertebrates varied between monospecific and interspersed stands, but not between monospecific and clumped stands. These results suggest that variation in the configuration of subtidal algae (stands measured at a 1‐m2 scale) has the potential to influence the composition and abundance of associated biota. We suggest that although studies in stands of monospecific E. radiata may provide useful information for the majority of forests containing E. radiata (monospecific and clumped stands made up 65% of forests sampled), caution must be used when extrapolating to stands of mixed, interspersed algae (>31% of forests sampled). 相似文献
44.
The Cyclic Production of 5-Hydroxytryptamine in the Opilionid 总被引:1,自引:0,他引:1
Techniques were developed for the measurement of two cyclicresponses in the opilionid, Leiobunum longipes. These responseswere an overt locomotor behavior and an internal secretory activity,both measured over a 24-hour period. An activity platform was designed to measure and to record continuouslythe movements of the opilionid. The procedure of fluorometricanalysis, used to quantitate indoles, was adapted for use withthe opilionid and the presence of the neurosecretory compound,5-hydroxytryptamine, was established. A method was developedfor maintaining tissues in culture over extended periods. Adult males and females of Leiobunum longipes showed a unimodalpattern of locomotor activity. The pattern of secretion of 5-HTwas also shown to be unimodal in character. There was an interestingparallel between the patterns of activity and secretion of 5-HT,with greatest peak at 2:00 AM, which suggested a relationshipbetween the two. The secretion, of 5-HT from tissues in vitro showed a bimodalcyclic output with a primary peak at 2:00 AM. A secondary peakoccurred at midmorning, when the secretion in intact animalswas at a low point. 相似文献
45.
MILLS W. RONALD; REEVES MICHELE; FOWLER DIANA L.; CAPO STEPHEN F. 《Journal of experimental botany》1989,40(4):425-429
The influence of two DNA gyrase inhibitors, nalidixic acid andnovobiocin, on DNA synthesis in isolated pea chloroplasts wasexamined. Novobiocin at 15 mol m3 markedly lowered[3H]thymidine incorporation into DNA (3095% inhibition);while less effective, nalidixic acid at similar concentrationsalso diminished incorporation (2535% inhibition). Theinhibition of chloroplast DNA (ctDNA) biosynthesis by nalidixicacid and novobiocin was confirmed by autoradiography and densitometry.These data are consistent with the view that chloroplasts containa DNA gyrase-like enzyme which is necessary for DNA replication.Despite this, interpretation of the results is not straightforward,as both nalidixic acid and novobiocin also inhibited photosyntheticactivity. Each substance (at millimolar levels) reduced ferricyanide-dependentO2 evolution in isolated chloroplasts. However, at lower concentrations(0.050.3 mol m3) they slightly enhanced photosyntheticelectron flow; thus, these compounds may act as uncouplers ofphotophosphorylation as well as inhibitors of electron transport.Nalidixic acid and novobiocin at relatively low (0.1 mol m3)concentrations also strongly reduced CO2-dependent O2 evolution(an index of CO2 photo-assimilation) in isolated plastids. Thus,caution must be exercised in assessing results from studiesin which nalidixic acid and novobiocin are used with whole plants,cells, protoplasts or isolated chloroplasts. Key words: Chloroplast, DNA replication, novobiocin, nalidixic acid, DNA gyrase 相似文献
46.
Abstract. 1. The number of agromyzid species (Diptera: Agromyzidae) attacking British Umbelliferae generally increases with the size of the geographic range of the host, measured as occupied 10 km squares in the Atlas of the British Flora (Lawton & Price, 1979). 2. In the present study we tried to explain the large, residual variation in this species—area relationship using two new variables, namely the local abundance of the host plant, and the number of habitats within which it grows. 3. Local abundance was estimated from eight floras that map plant distributions within English countries by tetrads (2 times 2 km squares). Local abundance was defined as: Total number of occupied tetrads Total number of available tetrads within occupied 10 km squares 4. The number of habitats occupied by each host plant was taken from the only county flora to record plant habitats objectively, that for Warwickshire. 5. We expected to find a correlation between local abundance and the residuals from the national species—area relationship, with locally scarce plants having fewer agromyzids than expected from the sizes of their national ranges, and vice versa. 6. What we found was that size of geographic range and local abundance were highly correlated; hence their relative contributions to agromyzid species richness were difficult to disentangle. Residuals from the national species—area relationship were positively correlated with local abundance, but the relationship marginally failed to achieve statistical significance (P= 0.06). 7. In contrast, the number of habitats occupied by each species of umbellifer in Warwickshire had a marked effect upon agrornyzid species richness, with plants that grow in more habitats supporting more species of insects. Not surprisingly, local abundance and number of habitats occupied were highly correlated. 8. Lawton & Price's observation that aquatic umbellifers are faunally impoverished now emerges as part of the general effect of number of habitats occupied by the host plants on agromyzid species richness. 9. Once the number of habitats occupied by each host plant in Warwickshire was entered into a multiple regression, the effect of size of host geographic range on agromyzid species richness was no longer statistically significant. 10. A combination of the number of habitats occupied, and leaf-form of the host (the latter taken from Lawton & Price, 1979), explains 61% of the variation in agromyzid species richness on British Umbelliferae. 相似文献
47.
48.
49.
Stages of Age-Related Reproductive Success in Birds: Simultaneous Effects of Age, Pair-Bond Duration and Reproductive Experience 总被引:2,自引:0,他引:2
SYNOPSIS. Most organisms reproduce episodically rather thancontinuously. Forms of discontinuity may include seasonal breedingin annual cycles, and delayed breeding and/or senescence overthe lifespan of individuals. In addition, age can have profoundeffects on the annual reproductive success (RS) of a wide varietyof animals. Explanations of the effects of age on RS can beconfounded, however, by the acquired breeding experience ofindividuals, and the duration of pair-bonds, both of which haveeffects on RS similar to those of age itself. However, moststudies of the effects of age on RS prior to senescence havenot accounted for the effects of pair-bond duration, and manyhave treated age and experience as synonyms. In this paper Isummarize the effects of all three factors, discuss the simultaneousand interrelated nature of their effects, and suggest ways toseparate the relative contributions of each. 相似文献
50.
The effects of foliage damage on casebearing moth larvae, Coleophora serratella, feeding on birch 总被引:1,自引:1,他引:0
ABSTRACT.
- 1 Mechanical damage to birch (Betula pendula Roth) leaves leads to an increase in the concentration of phenolic compounds, which spreads throughout the leaf within 8 days.
- 2 Coleophora serratella L. (Lepidoptera: Coleophoridae) apparently responds to this chemical change over a similar time scale. Within 24 h of pin-pricking leaves the casebearer moves from the immediate vicinity of the damage, but is just as likely to move to an undamaged portion of the damaged leaf as to vacate the leaf entirely. After 8 days mines on undamaged portions of damaged leaves were significantly smaller than mines on undamaged leaves.
- 3 Furthermore, Coleophora serratella reared on damaged trees took an average of 3 days longer to develop than those reared on undamaged trees.
- 4 It has been suggested that increased movement in response to damage-induced chemical changes causes hyperdispersed damage on plant foliage. Both within and between-leaf casebearer damage patterns were shown to be aggregated on birch.
- 5 Thus although mechanical damage can induce chemical and behavioural changes in the field, these are not reflected in the observed damaged patterns. We speculate on several possible reasons for this.