We report that Western Sandpipers （Calidris mauri） on Alaska’s Yukon-Kuskokwim River Delta exhibited aggregated breeding behavior at a relatively small spatial scale. Prior to clutch initiation, males performing so...We report that Western Sandpipers （Calidris mauri） on Alaska’s Yukon-Kuskokwim River Delta exhibited aggregated breeding behavior at a relatively small spatial scale. Prior to clutch initiation, males performing song flight displays on a 36 ha plot were aggregated as were subsequent initial nesting attempts on the plot. We tested three hypotheses commonly invoked to explain aggregated breeding in territorial species （social mate choice, predation, and material resources hypotheses）, and found support for the material resources hypothesis, as dispersed individuals were more often associated with tundra habitat patches, and aggregated individuals nested more often in undulating-tundra habitat patches compared to patch availability. The pattern of habitat occupancy conformed to an ideal despotic distribution with aggregated nesting birds in undulating-tundra patches experiencing lower reproductive success. On our study plot, older, more aggressive males solicited females more often, and defended larger, more dispersed sites in tundra habitat patches, compared to younger, less aggressive males that were aggregated in undulating-tundra habitat patches. Breeding aggregations are often concentrated on or near a critical resource. In contrast, Western Sandpiper breeding aggregations occur when dominant and/or older individuals exclude younger, subordinate individuals from preferred habitat. Although many taxa of non-colonial birds have been reported to aggregate breeding territories, this is the first quantitative report of aggregated breeding behavior in a non-colonial monogamous shorebird species prior to hatch.展开更多
Dried anaerobic granular sludge （DAGS） for removing phenol （organic） and lead （inorganic） pollutants from synthetic wastewater was examined in a fixed bed system. A general rate multi-component model has been bu...Dried anaerobic granular sludge （DAGS） for removing phenol （organic） and lead （inorganic） pollutants from synthetic wastewater was examined in a fixed bed system. A general rate multi-component model has been built to predict the fixed bed breakthrough curves for single and dual-component system. This model considers both external and internal mass transfer resistances as well as axial dispersion with non-liner multi-component isotherm. The equilibrium isotherm model parameters such as isotherm model constants （qm and b）, pore diffusion coefficients （Dp） were obtained from batch experiments, while the external mass transfer coefficients and axial dispersion （kf, Dz） were calculated from empirical correlations. The results show that the general rate multi-component model was found suitable for describing the biosorption process of the dynamic behavior of the DAGS adsorber column and that DAGS can be used efficiently to remove organic and inorganic pollutants.展开更多
文摘We report that Western Sandpipers （Calidris mauri） on Alaska’s Yukon-Kuskokwim River Delta exhibited aggregated breeding behavior at a relatively small spatial scale. Prior to clutch initiation, males performing song flight displays on a 36 ha plot were aggregated as were subsequent initial nesting attempts on the plot. We tested three hypotheses commonly invoked to explain aggregated breeding in territorial species （social mate choice, predation, and material resources hypotheses）, and found support for the material resources hypothesis, as dispersed individuals were more often associated with tundra habitat patches, and aggregated individuals nested more often in undulating-tundra habitat patches compared to patch availability. The pattern of habitat occupancy conformed to an ideal despotic distribution with aggregated nesting birds in undulating-tundra patches experiencing lower reproductive success. On our study plot, older, more aggressive males solicited females more often, and defended larger, more dispersed sites in tundra habitat patches, compared to younger, less aggressive males that were aggregated in undulating-tundra habitat patches. Breeding aggregations are often concentrated on or near a critical resource. In contrast, Western Sandpiper breeding aggregations occur when dominant and/or older individuals exclude younger, subordinate individuals from preferred habitat. Although many taxa of non-colonial birds have been reported to aggregate breeding territories, this is the first quantitative report of aggregated breeding behavior in a non-colonial monogamous shorebird species prior to hatch.
文摘Dried anaerobic granular sludge （DAGS） for removing phenol （organic） and lead （inorganic） pollutants from synthetic wastewater was examined in a fixed bed system. A general rate multi-component model has been built to predict the fixed bed breakthrough curves for single and dual-component system. This model considers both external and internal mass transfer resistances as well as axial dispersion with non-liner multi-component isotherm. The equilibrium isotherm model parameters such as isotherm model constants （qm and b）, pore diffusion coefficients （Dp） were obtained from batch experiments, while the external mass transfer coefficients and axial dispersion （kf, Dz） were calculated from empirical correlations. The results show that the general rate multi-component model was found suitable for describing the biosorption process of the dynamic behavior of the DAGS adsorber column and that DAGS can be used efficiently to remove organic and inorganic pollutants.
