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911.
Canchao Yang Longwu Wang Shun-Jen Cheng Yu-Cheng Hsu Wei Liang Anders Pape Møller 《Die Naturwissenschaften》2014,101(9):727-734
Parasites may, in multi-parasite systems, block the defenses of their hosts and thus thwart host recognition of parasites by frequency-dependent selection. Nest defenses as frontline may block or promote the subsequent stage of defenses such as egg recognition. We conducted comparative studies of the defensive strategies of a host of the Oriental cuckoo Cuculus optatus, the yellow-bellied prinia Prinia flaviventris, in mainland China with multiple species of cuckoos and in Taiwan with a single cuckoo species. Cuckoo hosts did not exhibit aggression toward cuckoos in the presence of multiple cuckoo species but showed strong aggressive defenses of hosts directed toward cuckoos in Taiwan. Furthermore, the cuckoo host in populations with a single cuckoo species was able to distinguish adults of its brood parasite, the Oriental cuckoo, from adult common cuckoos (Cuculus canorus). This represents the first case in which a cuckoo host has been shown to specifically distinguish Oriental cuckoo, from other Cuculus species. Hosts ejected eggs at a higher rate in a single cuckoo species system than in a multi-species cuckoo system, which supports the strategy facilitation hypothesis. Granularity analysis of variation in egg phenotype based on avian vision modeling supported the egg signature hypothesis in hosts because Taiwanese prinias increased consistency in the appearance of their eggs within individual hosts thus favoring efficient discrimination against cuckoo eggs. This study significantly improves our knowledge of intraspecific variation in antiparasitism behavior of hosts between single- and multi-cuckoo systems. 相似文献
912.
Coevolution is defined as specialized relationships between species that lead to a reciprocal evolutionary change. A particularly
suitable model system for studying coevolution is the interactions between obligate avian brood parasites and their hosts.
The common cuckoo (Cuculus canorus, hereafter cuckoo) is a well-known brood parasite, which utilizes a range of smaller passerines as hosts. However, warblers
of the genus Hippolais have rarely been reported as being victims of cuckoos, and furthermore, few data exist on the occurrence of antiparasite
defenses in these hosts. In this study, we examined possible host–parasite coevolution between cuckoos and eastern olivaceous
warblers (Hippolais pallida elaeica, hereafter olivaceous warblers) in three closely situated areas in northwestern Bulgaria. The olivaceous warbler has never
been reported to be a regular cuckoo host. However, the present study, carried out in 2001–2003 shows that the olivaceous
warbler is regularly and heavily parasitized by the cuckoo in this area. Parasitism rate was high (26.6%, 34/128) and consistent
among years, with some variation between areas. The cuckoo egg mimicry was moderately good, and olivaceous warbler rejection
rate of such eggs was 50%. Cuckoo eggs laid in olivaceous warbler nests had a whitish to whitish-green ground color, and the
majority appeared to be distinctly different from cuckoo eggs found in other host species in the area. The olivaceous warbler
proved to be a rather good host for cuckoos as 20.6% (7/34) of cuckoo eggs laid produced fledglings, a breeding success comparable
to other suitable hosts in Europe. This is the first in-depth study of brood parasitism in a warbler of the genus Hippolais, and cuckoos parasitizing olivaceous warblers probably represent a previously unknown gens. 相似文献
913.
Asbjørn Aaheim Ranjith Gopalakrishnan Rajiv Kumar Chaturvedi N. H. Ravindranath Anitha D. Sagadevan Nitasha Sharma Taoyuan Wei 《Mitigation and Adaptation Strategies for Global Change》2011,16(2):229-245
We examine the potential for adaptation to climate change in Indian forests, and derive the macroeconomic implications of
forest impacts and adaptation in India. The study is conducted by integrating results from the dynamic global vegetation model
IBIS and the computable general equilibrium model GRACE-IN, which estimates macroeconomic implications for six zones of India.
By comparing a reference scenario without climate change with a climate impact scenario based on the IPCC A2-scenario, we
find major variations in the pattern of change across zones. Biomass stock increases in all zones but the Central zone. The
increase in biomass growth is smaller, and declines in one more zone, South zone, despite higher stock. In the four zones
with increases in biomass growth, harvest increases by only approximately 1/3 of the change in biomass growth. This is due
to two market effects of increased biomass growth. One is that an increase in biomass growth encourages more harvest given
other things being equal. The other is that more harvest leads to higher supply of timber, which lowers market prices. As
a result, also the rent on forested land decreases. The lower prices and rent discourage more harvest even though they may
induce higher demand, which increases the pressure on harvest. In a less perfect world than the model describes these two
effects may contribute to an increase in the risk of deforestation because of higher biomass growth. Furthermore, higher harvest
demands more labor and capital input in the forestry sector. Given total supply of labor and capital, this increases the cost
of production in all the other sectors, although very little indeed. Forestry dependent communities with declining biomass
growth may, however, experience local unemployment as a result. 相似文献
914.
915.
A. Fossdal E. Bakken B.A. Øye C. Schøning I. Kaus T. Mokkelbost Y. Larring 《International Journal of Greenhouse Gas Control》2011,5(3):483-488
Norwegian industrial tailings and by-products, as well as naturally occurring minerals and ores have been surveyed with the purpose of identifying candidate oxygen carrier materials for use in a chemical looping combustion process. Nine materials, based on manganese and/or iron oxide, were selected for an initial screening test; six were deemed promising and were hence investigated further. Thermogravimetric experiments were performed to investigate the oxygen capacity, the reaction kinetics and reversibility of the oxygen absorption reaction. A manganese ore with a reversible capacity of 4.9 wt% oxygen at 1000 °C was selected as the most promising for chemical looping combustion applications. This material was modified by addition of calcia to explore the possibility of enhancing the kinetic, catalytic and mechanical properties. The addition of excess calcium relative to manganese resulted in formation of calcium manganite and related phases. The oxygen capacity of the modified material was 4.5 wt% at 1000 °C, but it has potential advantages in terms of kinetics and chemical and mechanical stability relative to the pure ore. 相似文献
916.
Hansen TL Jansen Jl Davidsson A Christensen TH 《Waste management (New York, N.Y.)》2007,27(3):398-405
Source-sorted municipal organic waste collected from different dwelling types in five Danish cities and pre-treated at three different plants was sampled and characterized several times during one year to investigate the origin of any differences in composition of the pre-treated waste introduced by city, pre-treatment technology, dwelling type or annual season. The investigated pre-treatment technologies were screw press, disc screen and shredder+magnet. The average quantity of pre-treated organic waste (biomass) produced from the incoming waste varied between the investigated pre-treatment technologies: 59%, 66% and 98% wet weight, respectively (41%, 34% and 2% reject, respectively). The pre-treatment technologies showed differences with respect to distribution of the chemical components in the waste between the biomass and the rejected material (reject), especially for dry matter, ash, collection bag material (plastic or paper) and easily degradable organic matter. Furthermore, the particle size of the biomass was related to the pre-treatment technology. The content of plastic in the biomass depended both on the actual collection bag material used in the system and the pre-treatment technology. The sampled reject consisted mostly of organic matter. For cities using plastic bags for the source-separated organic waste, the expected content of plastic in the reject was up to 10% wet weight (in some cases up to 20%). Batch tests for methane potential of the biomass samples showed only minor variations caused by the factors city, pre-treatment technology, dwelling type and season when based on the VS content of the waste (overall average 459STPm(3)/tVS). The amount of methane generated from 1t of collected waste was therefore mainly determined by the efficiency of the chosen pre-treatment technology described by the mass distribution of the incoming waste between biomass and reject. 相似文献
917.
A steady state redox zone approach for modeling the transport and degradation of xenobiotic organic compounds from a landfill site 总被引:1,自引:0,他引:1
A redox zonation approach is used as a framework for obtaining biodegradation rate constants of xenobiotic compounds in a landfill plume (Grindsted, Denmark). The aquifer is physically heterogeneous in terms of a complex zonation of different geological units close to the landfill and biogeochemically heterogeneous in terms of a specified redox zonation. First-order degradation rates of six organic compounds (benzene, toluene, ethylbenzene, o-xylene, m/p-xylene, and naphthalene) were calculated in the methanogenic/sulfate- and Fe-reducing zones. The numerical simulations show that all compounds are anaerobically biodegraded, but at very different rates. High rates of biodegradation of most of the compounds (except benzene) were found in the Fe-reducing zone. These rates generally agree with previously published rates. Only o-xylene and toluene were significantly biodegraded in the methanogenic/sulfate-reducing environment. All rates in this redox zone are generally much lower than previously published rates. 相似文献
918.
Jansson JK Björklöf K Elvang AM Jørgensen KS 《Environmental pollution (Barking, Essex : 1987)》2000,107(2):217-223
Bioaugmentation of contaminated sites with microbes that are adapted or genetically engineered for degradation of specific toxic compounds is an area that is currently being explored as a clean-up option. Biomarkers have been developed to track the survival and efficacy of specific bacteria that are used as inocula for bioremediation of contaminated soil. Examples of biomarkers include the luc gene, encoding firefly luciferase and the gfp gene, encoding the green fluorescent protein (GFP). The luc gene was used to tag different bacteria used for bioremediation of gasoline or chlorophenols. The bacteria were monitored on the basis of luciferase activity in cell extracts from soil. The gfp gene was also used to monitor bacteria during degradation of chlorophenol in soil, based on fluorescence of the GFP protein. Other biomarkers can also be used for monitoring of microbial inocula used for bioaugmentation of contaminated sites. The choice of biomarker and monitoring system depends on the particular site, bacterial strain and sensitivity and specificity of detection required. 相似文献
919.
Milford Anna Birgitte Hatteland Bjørn Arild Ursin Lars Øystein 《Journal of Agricultural and Environmental Ethics》2022,35(3):1-21
Journal of Agricultural and Environmental Ethics - This study examines the influence of environmental values on consumer intentions to participate in agritourism through the theory of planned... 相似文献