نتایج جستجو برای: five transects
تعداد نتایج: 401798 فیلتر نتایج به سال:
The invasion of exotic earthworms into northern temperate and boreal forests previously devoid of earthworms is an important driver of ecosystem change. Earthworm invasion can cause significant changes in soil structure and communities, nutrient cycles, and the diversity and abundance of herbaceous plants. However, the regional extent and patterns of this invasion are poorly known. We conducted...
Parker (1) has shown that the results of infectivity measurements with vaccinia virus may be interpreted as a Poisson distribution of single infective particles among aliquots of the virus obtained by dilution. Thus, if it may be assumed that there exists a quanti ty of virus invariably necessary and invariably sufficient to produce a lesion in the skin of the rabbit, the behavior on dilution r...
Turkey has initiated a number of projects to improve the quality of education and to provide students with knowledge and skills needed for the job market through the integration of information and communication technology (ICT) into education during the last twenty-five years. This paper is an overview of those initiatives of ICT in education in Turkey. It is argued that more attention is neede...
The analysis of interactions between lineages at varying levels of genetic divergence can provide insights into the process of speciation through the accumulation of incompatible mutations. Ring species, and especially the Ensatina eschscholtzii system exemplify this approach. The plethodontid salamanders E. eschscholtzii xanthoptica and E. eschscholtzii platensis hybridize in the central Sierr...
[1] Longitudinal and diel measurements of dual isotope composition (dN and dO) in nitrate (NO3-N) were made in the Ichetucknee River, a large ( 8 m s ), entirely spring-fed river in North Florida, to determine whether isotopic variation can deconvolve assimilatory and dissimilatory removal. Comparing nitrate concentrations and isotope composition during the day and night we predicted (1) daytim...
Here I present a dataset of edaphic and light conditions associated with the occurrence of sympatric morphotypes of Geonomamacrostachys (Arecaceae/Palmae), a candidate case study from Amazonia hypothesized to have evolved under ecological speciation. Transects were established in three lowland rainforests in Peru, and the abundance of each local morphotype of this species was recorded in a tota...
Rapid survey methods are needed that accurately detect both species richness and relative abundance for surveying new sites and/or for long-term monitoring. We investigate whether the large-scale gradsect survey method of Gillison can be adapted for a smaller scale more suitable for monitoring or research. Three different designs that are compared are typical random small plot sampling and two ...
Atmospheric sampling of organochlorine pesticides (OCPs) was conducted using Semi Permeable Membrane Devices (SPMDs) deployed in the Alps at different altitudinal transects for two consecutive exposure periods of half a year and a third simultaneous year-long period. Along all the altitude profiles, the sequestered amounts of OCPs increased in general with altitude. SPMDs were still working as ...
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