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  • 1
    Publication Date: 2014-04-30
    Description: Speciation generally involves a three-step process--range expansion, range fragmentation and the development of reproductive isolation between spatially separated populations. Speciation relies on cycling through these three steps and each may limit the rate at which new species form. We estimate phylogenetic relationships among all Himalayan songbirds to ask whether the development of reproductive isolation and ecological competition, both factors that limit range expansions, set an ultimate limit on speciation. Based on a phylogeny for all 358 species distributed along the eastern elevational gradient, here we show that body size and shape differences evolved early in the radiation, with the elevational band occupied by a species evolving later. These results are consistent with competition for niche space limiting species accumulation. Even the elevation dimension seems to be approaching ecological saturation, because the closest relatives both inside the assemblage and elsewhere in the Himalayas are on average separated by more than five million years, which is longer than it generally takes for reproductive isolation to be completed; also, elevational distributions are well explained by resource availability, notably the abundance of arthropods, and not by differences in diversification rates in different elevational zones. Our results imply that speciation rate is ultimately set by niche filling (that is, ecological competition for resources), rather than by the rate of acquisition of reproductive isolation.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Price, Trevor D -- Hooper, Daniel M -- Buchanan, Caitlyn D -- Johansson, Ulf S -- Tietze, D Thomas -- Alstrom, Per -- Olsson, Urban -- Ghosh-Harihar, Mousumi -- Ishtiaq, Farah -- Gupta, Sandeep K -- Martens, Jochen -- Harr, Bettina -- Singh, Pratap -- Mohan, Dhananjai -- England -- Nature. 2014 May 8;509(7499):222-5. doi: 10.1038/nature13272. Epub 2014 Apr 30.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Ecology and Evolution, University of Chicago, Chicago, Illinois 60637, USA. ; 1] Department of Ecology and Evolution, University of Chicago, Chicago, Illinois 60637, USA [2] Department of Zoology, Swedish Museum of Natural History, 10405 Stockholm, Sweden. ; 1] Department of Ecology and Evolution, University of Chicago, Chicago, Illinois 60637, USA [2] Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, Im Neuenheimer Feld 364, 69120 Heidelberg, Germany. ; 1] Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang District, Beijing 100101, China [2] Swedish Species Information Centre, Swedish University of Agricultural Sciences, Box 7007, 75007 Uppsala, Sweden. ; Systematics and Biodiversity, Department of Biology and Environmental Sciences, University of Gothenburg, 40530 Gothenburg, Sweden. ; Wildlife Institute of India, PO Box 18, Chandrabani, Dehradun 248001, India. ; Institute of Zoology, Johannes Gutenberg University, Mainz 55099, Germany. ; Max Planck Institute for Evolutionary Biology, August Thienemannstrasse 2, 24306 Plon, Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/24776798" target="_blank"〉PubMed〈/a〉
    Keywords: *Altitude ; Animals ; Body Size ; China ; *Ecosystem ; *Genetic Speciation ; India ; Phylogeny ; Reproduction ; Songbirds/anatomy & histology/*classification/*physiology ; Tibet
    Print ISSN: 0028-0836
    Electronic ISSN: 1476-4687
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Science Ltd
    European journal of soil science 49 (1998), S. 0 
    ISSN: 1365-2389
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: We investigated the potential of montmorillonite, Al-montmorillonite and gravel sludge to immobilize polluting heavy metals in agricultural soil. Batch experiments showed that both Al-montmorillonite and montmorillonite immobilized zinc and cadmium. Zinc was bound specifically on Al-montmorillonite and became increasingly incorporated into the interlayer hydroxy-Al polymer, whereas there was no specific sorption on montmorillonite. Cadmium was bound on montmorillonite and Al-montmorillonite unspecifically by cation exchange, but there was no incorporation into the lattice.In pot experiments montmorillonite, Al-montmorillonite, or gravel sludge were added to a soil contaminated with zinc and cadmium. Increasing doses of these agents decreased the concentrations of NaNO3-extractable zinc and cadmium. Aluminium-montmorillonite and gravel sludge were more efficient than montmorillonite in immobilizing both zinc and cadmium. Remobilization tests at pH between 4 and 5.5 showed that cadmium and zinc desorbed more easily from montmorillonite than from Al-montmorillonite. Gravel sludge application increased the buffer capacity of the contaminated soil substantially. The binding agents decreased zinc concentrations in red clover (Trifolium pratense), and gravel sludge also reduced the cadmium concentrations.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    PO Box 1354, 9600 Garsington Road, OxfordOX4 2XG, UK. : Blackwell Science Ltd
    Fatigue & fracture of engineering materials & structures 27 (2004), S. 0 
    ISSN: 1460-2695
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Earthquake load, which is cyclic in nature and of short duration, is the main design basis accident load for designing the primary heat transport (PHT) piping components of Nuclear Power Plants. Adequate protection of piping components from the effects of earthquake requires detailed knowledge of strength and deformation characteristics of the components and assemblies making up the piping system. Fracture behaviour of 23 pipes was studied by conducting cyclic tests under four-point bending. Fifteen pipes were of carbon steel (SA333 Grade 6) of 219 mm, 324 mm and 406 mm ODs and eight pipes were of stainless steel (AISI Type 304LN) of 168 mm OD with through-wall circumferential crack. Six pipes were tested under displacement control and the rest under load control. The effect of various parameters such as location and size of initial crack in base metal and weld metal, cyclic load range and displacement increment on crack growth and number of cycles for failure was investigated. The investigations showed significant reduction in the fracture resistance under cyclic loading conditions. Crack growth equations have been proposed for carbon steel pipes with and without weld under cyclic tearing.
    Type of Medium: Electronic Resource
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