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91.
All animals can learn to some extent and it should not be surprising to discover that important vectors can also be influenced by experience. The potential effect of memory on vector behaviour, particularly vectorial capacity, has barely been investigated. Yet, how a population of blood-feeding insects distributes between available resources has important epidemiological consequences. Several recent studies have shown that behaviour during oviposition site-selection, host location and even host choice can be influenced by the environment or by experience after eclosion. The significance of these studies and their consequences for epidemiology and control are considered here. 相似文献
92.
David L. Hull 《Biology & philosophy》2000,15(1):61-91
During the past hundred years or so, those scholars studying science have isolated themselves as much as possible from scientists as well as from workers in other disciplines who study science. The result of this effort is history of science, philosophy of science and sociology of science as separate disciplines. I argue in this paper that now is the time for these disciplinary boundaries to be lowered or at least made more permeable so that a unified discipline of Science Studies might emerge. I discuss representative problems that stand in the way of such an integration. These problems may seem so formidable in the abstract that no one in their right mind would waste their time trying to bring about a unified field of Science Studies. However, those of us who limit ourselves to the study of the biological sciences have already formed a society in which workers from all disciplines can share their expertise -- the International Society for the History, Philosophy and Social Studies of Science. 相似文献
93.
A seven-year study of marked plants and plots in Stipagrostis ciliata (Desf.) de Winter dune grassland, in the arid (<100 mm yr–1) Bushmanland area of the Northern Cape province of South Africa, was designed to test the hypothesis that establishment of ephemeral plants, and recruitment of perennial grasses was dependent upon disturbances that reduced the density of living perennial grass tussocks. In 1989, eight 4 m2 plots were cleared of perennial vegetation by uprooting and removing all plants so as to resemble small-scale disturbances made by burrowing mammals or territorial antelope. The vegetation on the cleared plots and surroundings was monitored until 1996. Initial results supported our hypothesis. In wet years, when ephemeral plants were abundant, their average fresh mass was 2–3 times greater per unit area on the cleared plots than in control plots in adjacent, undisturbed grassland. Many Stipagrostis seedlings established in the cleared plots over the two years following clearing but were rare in adjacent areas among established conspecifics. However, a drought in 1992 (11 mm of rain over 12 months) lead to widespread mortality of the perennial grass, killing 56% (range 22–79%) of established tufts. High densities of Stipagrostis seedlings appeared following the drought-breaking rains in January 1993, both in the disturbed plots and in the surrounding `undisturbed' dune grassland. Ephemeral plants established in large numbers throughout the area during the high rainfall year of 1996 and were generally more numerous in the old disturbances than in control plots. Seven years after clearing the biomass of grass on the cleared plots was approximately 34% of the mass removed from the plots in 1989 whereas in the undisturbed grassland biomass was 66% of 1989 levels. Drought had little long-term effect on community composition, and Stipagrostis ciliata constituted 94–98% of plant community before and after drought. Cleared plots were recolonised by S. ciliata, but the contribution of other grass species increased by 6–9%. Synchronous recruitment following occasional drought-induced mortality can generate even-aged populations of the dominant desert dune grasses. 相似文献
94.
Synopsis A study of recolonisation of rockpools by intertidal fishes on the Wellington south coast, New Zealand, found the assemblage to be resilient and seasonally stable. A total of 26 species from nine families were recorded, dominated by the Tripterygiidae (triplefins) and Gobiesocidae (clingfishes). A pattern of alternating species dominance occurred, with the triplefinsBellapiscis medius andForsterygion lapillum being numerically dominant in summer, but becoming less common in winter and replaced as dominants by the clingfishesTrachelochismus pinnulatus andGastroscyphus hectoris. Juvenile recruits of eleven species occurred in the samples from spring to early summer, however only the aforementioned four species recruit to the intertidal zone in large numbers. The speed of rockpool recolonisation by fishes after extractive sampling is seasonally dependent, being quicker in the summer than winter. In general, recolonisation takes at least one month, but probably fewer than three. While stochastic factors influence assemblage composition in the short term, overall regulation of the fish assemblage of rockpools appears to be primarily deterministic, resulting in an essentially predictable taxonomic structure. 相似文献
95.
国家自然科学基金评审程序剖析──1993年和1994年植物学科面上基金项目分析陈峰,朱大保(中国科学院武汉植物研究所武汉430074)(国家自然科学基金委员会生命科学部北京100083)关键词基金,评审,科研立项,学科ANALYSLSFORJUDGE... 相似文献
96.
97.
Summary Using data from three fires in northeastern Spain, we tested a condition necessary to support the idea that fire has been
a factor in the evolution of the resprouting habit: populations of all resprouting species within a community should show
high levels of genet survival after fires and show a low coefficient of variation. Species with high mean survival values
were:Quercus ilex L.,Phillyrea latifolia L., andViburnum tinus L., with 88, 86 and 83% survival respectively; these groups had resprouts emerging from rootcrowns. Then followedArbutus unedo L. (75%),Pistacia lentiscus L. (73%),Erica arborea L. (77%),Erica multiflora L. (57%) andJuniperus oxycedrus L. (55%). This last group had resprouts from lignotubers or burls. These two groups also differed in the variability around
the mean: the first showed a lower coefficient of variation, 6–12, and the second ranged from 19 to 26. Slope exposure had
no significant influence on the process of resprouting, but soil depth did, with precipitation as a covariate. In the shallow
soil category, the difference in genet survival between southern and northern exposures was 14% (71% vs. 57%); while the difference
in the deep soil category was low, 5% (87% vs. 82%). There was no significant interaction. The component of variance for soils
was larger than that for species-specific effects; substantial overlap of the within-species variance indicated that species
responded as if they were a single hypothetical population, in which most of the variation in chances of survival was due
to the soil conditions. The possession of the resprouting habit did not ensure a high performance. Hence, we find weak support
for fire as a factor in the evolution of the resprouting habit. 相似文献
98.
Theoretical and empirical models of populations dynamics have paid little attention to the implications of density-dependent
individual growth on the persistence and regulation of small freshwater salmonid populations. We have therefore designed a
study aimed at testing our hypothesis that density-dependent individual growth is a process that enhances population recovery
and reduces extinction risk in salmonid populations in a variable environment subject to disturbance events. This hypothesis
was tested in two newly introduced marble trout (Salmo marmoratus) populations living in Slovenian streams (Zakojska and Gorska) subject to severe autumn floods. We developed a discrete-time
stochastic individual-based model of population dynamics for each population with demographic parameters and compensatory
responses tightly calibrated on data from individually tagged marble trout. The occurrence of severe flood events causing
population collapses was explicitly accounted for in the model. We used the model in a population viability analysis setting
to estimate the quasi-extinction risk and demographic indexes of the two marble trout populations when individual growth was
density-dependent. We ran a set of simulations in which the effect of floods on population abundance was explicitly accounted
for and another set of simulations in which flood events were not included in the model. These simulation results were compared
with those of scenarios in which individual growth was modelled with density-independent Von Bertalanffy growth curves. Our
results show how density-dependent individual growth may confer remarkable resilience to marble trout populations in case
of major flood events. The resilience to flood events shown by the simulation results can be explained by the increase in
size-dependent fecundity as a consequence of the drop in population size after a severe flood, which allows the population
to quickly recover to the pre-event conditions. Our results suggest that density-dependent individual growth plays a potentially
powerful role in the persistence of freshwater salmonids living in streams subject to recurrent yet unpredictable flood events.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
99.
Life scientists today cannot hope to read everything relevant to their research. Emerging text-mining tools can help by identifying topics and distilling statements from books and articles with increased accuracy. Researchers often organize these statements into ontologies, consistent systems of reality claims. Like scientific thinking and interchange, however, text-mined information (even when accurately captured) is complex, redundant, sometimes incoherent, and often contradictory: it is rooted in a mixture of only partially consistent ontologies. We review work that models scientific reason and suggest how computational reasoning across ontologies and the broader distribution of textual statements can assess the certainty of statements and the process by which statements become certain. With the emergence of digitized data regarding networks of scientific authorship, institutions, and resources, we explore the possibility of accounting for social dependences and cultural biases in reasoning models. Computational reasoning is starting to fill out ontologies and flag internal inconsistencies in several areas of bioscience. In the not too distant future, scientists may be able to use statements and rich models of the processes that produced them to identify underexplored areas, resurrect forgotten findings and ideas, deconvolute the spaghetti of underlying ontologies, and synthesize novel knowledge and hypotheses. 相似文献
100.
Pölzl C 《Progress in biophysics and molecular biology》2011,107(3):467-472
When discussing health risks for children due to electromagnetic fields it is crucial to translate scientific knowledge both into adequate protection and precautionary measures for the general public and, more particularly into specific recommendations for children. It is often aimed at influencing health-related attitudes and behaviour by means of information about health affecting behaviour, health risk factors, and health promoting possibilities. Children have to be treated differently from adults in addressing their ability and willingness to modify behaviour and their competence to comprehend cognitively the sense of behavioural recommendations. Research has shown that adults can be motivated to adjust their own behaviour in order to protect their children or to be role models for their children. Hence one way to modify children’s behaviour is to address the parents and care persons. Generally education in the family, the social environment and in peer groups, nursery school and at school plays an important role in forming and influencing individual behaviour. The age of the target group has also to be taken into consideration.An important question is how to deal with scientific uncertainties when expressing EMF recommendations for children. Accentuating scientific uncertainties may under certain circumstances raise risk awareness. This can be an intended effect. But the expression of scientific uncertainties can also lead to unintended consequences in parent’s behaviour or even senseless dealing with the respective EMF source.The paper points out relevant aspects of risk communication regarding EMF and children and suggests how recommendations for children might be designed. 相似文献