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81.
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83.
Extra-pair paternity and the opportunity for sexual selection in a socially monogamous bird (Dendroica petechia) 总被引:7,自引:0,他引:7
Stephen M. Yezerinac Patrick J. Weatherhead Peter T. Boag 《Behavioral ecology and sociobiology》1995,37(3):179-188
We used multi-locus DNA fingerprinting to characterise the genetic mating system of the socially monogamous yellow warbler (Dendroica petechia). Over 2 years there were no instances of brood parasitism, but 59% of families (n = 90) contained extrapair sired young and 37% of offspring (n = 355) were of extra-pair paternity. Most hypotheses for extra-pair mating in monogamous species assume a paternity benefit to extra-pair sires, and focus on the benefit(s) to females. However, the assumption of male benefit has been little tested. Among yellow warblers, known extra-pair sires were just as likely to be cuckolded as any male in the population, and there was at least one reciprocal exchange of extra-pair paternity. Nevertheless, among known extra-pair sires, the paternity gains from extra-pair paternity were, on average, greater than the losses in their own families. These results show there is a paternity benefit to certain males. However, the benefit is not absolute but relative and therefore more difficult to measure. The results also suggest that patterns of extra-pair fertilisation are not determined by female choice alone. Most confirmed extra-pair mates were territorial neighbours, but some resided as far as three territories apart, and greater spatial separation was implied in other cases. Thus, the opportunity for extra-pair mating is great. We estimate that as a result of extra-pair fertilisations, variance in male mating success is increased somewhere between 3-fold and 15-fold over that which would result from within-pair reproduction alone. These findings affirm the potential importance of extra-pair reproduction for sexual selection in monogamous species and they support earlier suggestions that extra-territorial forays by male yellow warblers are for the purpose of extra-pair mating. 相似文献
84.
85.
Mojca Loncnar Marija Zupančič Peter Bukovec Maja Zupančič Justin 《Waste management (New York, N.Y.)》2010,30(1):110-118
Recirculation of leachate on a covered landfill site planted with willows or other highly evapotranspirative woody plants is an inexpensive option for leachate management. In our study, a closed landfill leachate recirculation system was established on a rehabilitated municipal solid waste landfill site with planted landfill cover. The main objective of the study was to evaluate the sustainability of the system with regard to high hydraulic loads of the landfill leachate on the landfill cover and high concentrations of saline ions, especially potassium (K+), sodium (Na+) and chloride (Cl?), in leachate.The results of intensive monitoring, implemented during May 2004 and September 2007, including leachate, soil and plant samples, showed a high sustainability of the system regarding saline ions with the precipitation regime of the studied region. Saline ion concentrations in leachates varied between 132 and 2592 mg Cl? L?1, 69 and 1310 mg Na+ L?1 and between 66 and 2156 mg K+ L?1, with mean values of 1010, 632 and 686 mg L?1, respectively. Soil salinity, measured as soil electrical conductivity (EC), remained between 0.17 and 0.38 mS cm?1 at a depth between 0 and 90 cm. An average annual precipitation of 1000 mm provided sufficient leaching of saline ions, loaded by irrigation with landfill leachate, from the soil of the landfill cover and thus prevented possible salinity shocks to the planted willows. 相似文献
86.
Modelling of stable isotope fractionation by methane oxidation and diffusion in landfill cover soils 总被引:2,自引:0,他引:2
Mahieu K De Visscher A Vanrolleghem PA Van Cleemput O 《Waste management (New York, N.Y.)》2008,28(9):1535-1542
A technique to measure biological methane oxidation in landfill cover soils that is gaining increased interest is the measurement of stable isotope fractionation in the methane. Usually to quantify methane oxidation, only fractionation by oxidation is taken into account. Recently it was shown that neglecting the isotope fractionation by diffusion results in underestimation of the methane oxidation. In this study a simulation model was developed that describes gas transport and methane oxidation in landfill cover soils. The model distinguishes between (12)CH(4), (13)CH(4), and (12)CH(3)D explicitly, and includes isotope fractionation by diffusion and oxidation. To evaluate the model, the simulations were compared with column experiments from previous studies. The predicted concentration profiles and isotopic profiles match the measured ones very well, with a root mean square deviation (RMSD) of 1.7vol% in the concentration and a RMSD of 0.8 per thousand in the delta(13)C value, with delta(13)C the relative (13)C abundance as compared to an international standard. Overall, the comparison shows that a model-based isotope approach for the determination of methane oxidation efficiencies is feasible and superior to existing isotope methods. 相似文献
87.
The technical viability of using inert construction and demolition (C&D) materials for the construction of seawall and breakwater foundations has been established by laboratory testing of the materials, numerical analysis of foundation stability, and a pilot field-scale engineering performance evaluation. However, quality control measures are still required so that only suitable materials are used for seawall and breakwater foundation construction. The development of different quality control measures for different site conditions is presented in this paper. The rationale, practicality, and implementation of these quality control measures are also discussed. 相似文献
88.
Kristen Kruger Woods Gordon W. Selling Peter H. Cooke 《Journal of Polymers and the Environment》2009,17(2):115-122
Blends of zein and polyvinylpyrrolidone (PVP) were compared based on their tensile properties, thermal properties and morphology.
Zein was blended with polyvinylpyrrolidone of varying molecular weights (10, 55, and 1,300 kDa) and films were cast from ethanol
solutions. Films cast using the higher molecular weight polymers showed an improvement in tensile strength, up to a 24% increase,
compared to control. Differential scanning calorimetry data for the blends showed single Tm and Tg values of an intermediate value between those of zein and PVP control samples. Field emission scanning electron microscopy
images show no obvious inhomogeneities, and confocal fluorescence microscopy showed no decreased uniformity in the PVP/zein
films compared to control. Electrospun fibers of the zein/PVP blends were also obtained. These findings suggest that zein
and polyvinylpyrrolidone combine to form a compatible blend, the first such blend of zein with a synthetic polymer. 相似文献
89.
A Coupled Land-Surface and Dry Deposition Model and Comparison to Field Measurements of Surface Heat,Moisture, and Ozone Fluxes 总被引:1,自引:0,他引:1
Pleim Jonathan E. Xiu Aijun Finkelstein Peter L. Otte Tanya L. 《Water, Air, & Soil Pollution: Focus》2001,1(5-6):243-252
We have developed a coupled land-surface and drydeposition model for realistic treatment of surface fluxes ofheat, moisture, and chemical dry deposition within acomprehensive air quality modelling system. A new land-surfacemodel (LSM) with explicit treatment of soil moisture andevapotranspiration and an indirect soil moisture nudging schemehas been added to a mesoscale meteorology model. The new drydeposition model uses the same aerodynamic and bulk stomatalresistances computed for evapotranspiration in the LSM. Thisprovides consistent land-surface and boundary layer propertiesacross the meteorological and chemical components of the system. The coupled dry deposition model also has the advantage of beingable to respond to changing soil moisture and vegetationconditions. Modelled surface fluxes of sensible and latent heatas well as ozone dry deposition velocities were compared to twofield experiments: a soybean field in Kentucky during summer 1995and a mixed forest in the Adirondacks of New York in July 1998.(on assignment to the National Exposure Research Laboratory, U.S. Environmental Protection Agency) (author for correspondence, e-mail(on assignment to the National Exposure Research Laboratory, U.S. Environmental Protection Agency) 相似文献
90.
Lorien Pichegru Peter G. Ryan Robert J. M. Crawford Carl D. van der Lingen David Grémillet 《Marine Biology》2010,157(3):537-544
In variable environments, organisms are bound to track environmental changes if they are to survive. Most marine mammals and
seabirds are colonial, central-place foragers with long-term breeding-site fidelity. When confronted with environmental change,
such species are potentially constrained in their ability to respond to these changes. For example, if environmental conditions
deteriorate within their limited foraging range, long-lived species favour adult survival and abandon their current breeding
effort, which ultimately influences population dynamics. Should poor conditions persist over several seasons, breeding-site
fidelity may force animals to continue breeding in low-quality habitats instead of emigrating towards more profitable grounds.
We assessed the behavioural response of a site-faithful central-place forager, the Cape gannet Morus capensis, endemic to the Benguela upwelling system, to a rapid shift in the distribution and abundance of its preferred prey, small
pelagic shoaling fish. We studied the distribution and the abundance of prey species, and the diet, foraging distribution,
foraging effort, energy requirements, and breeding success of gannets at Malgas Island (South Africa) over four consecutive
breeding seasons. Facing a rapid depletion of preferred food within their foraging range, Cape gannets initially increased
their foraging effort in search of their natural prey. However, as pelagic fish became progressively scarcer, breeding birds
resorted to scavenging readily available discards from a nearby demersal fishery. Their chicks cannot survive on such a diet,
and during our 4-year study, numbers of breeding birds at the colony decreased by 40% and breeding success of the remaining
birds was very low. Such behavioural inflexibility caused numbers of Cape gannets breeding in Namibia to crash by 95% following
over-fishing of pelagic fish in the 1970s. In the context of rapid environmental changes, breeding-site fidelity of long-lived
species may increase the risk of local or even global extinction, rendering these species particularly vulnerable to global
change. 相似文献