Rivers are important habitats for wintering waterbirds.However,they are easily influenced by natural and human activities.An important approach for waterbirds to adapt to habitats is adjusting the activity time and en...Rivers are important habitats for wintering waterbirds.However,they are easily influenced by natural and human activities.An important approach for waterbirds to adapt to habitats is adjusting the activity time and energy expenditure allocation of diurnal behavior.The compensatory foraging hypothesis predicts that increased energy expenditure leads to longer foraging time,which in turn increases food intake and helps maintain a constant energy balance.However,it is unclear whether human-disturbed habitats result in increased energy expenditure related to safety or foraging.In this study,the scan sample method was used to observe the diurnal behavior of the wintering Spot-billed Duck(Anas poecilorhyncha) in two rivers in the Xin’an River Basin from October 2021 to March 2022.The allocation of time and energy expenditure for activity in both normal and disturbed environments was calculated.The results showed that foraging accounted for the highest percentage of time and energy expenditure.Additionally,foraging decreased in the disturbed environment than that in the normal environment.Resting behavior showed the opposite trend,while other behaviors were similar in both environments.The total diurnal energy expenditure of ducks in the disturbed environment was greater than that in the normal environment,with decreased foraging and resting time percentage and increased behaviors related to immediate safety(swimming and alert) and comfort.These results oppose the compensatory foraging hypothesis in favor of increased security.The optimal diurnal energy expenditure model included river width and water depth,which had a positive relationship;an increase in either of these two factors resulted in an increase in energy expenditure.This study provides a better understanding of energy allocation strategies underlying the superficial time allocation of wintering waterbirds according to environmental conditions.Exploring these changes can help understand the maximum fitness of wintering waterbirds in response to nature and h展开更多
This paper aims to inquire into an objectively authentic budget constraint in a monetary economy through showing two missing problems of the monetary budget constraint and their solutions. To start with, we show the f...This paper aims to inquire into an objectively authentic budget constraint in a monetary economy through showing two missing problems of the monetary budget constraint and their solutions. To start with, we show the first missing problem that money is “missing” if all agents expend their total budgets under the simple budget constraint. This problem shows that the simple budget constraint is inadequate as an objective monetary budget constraint. A deficiency of the simple budget constraint exists partly in that it does not reflect money circulation. To improve this deficiency, we incorporate the expenditure reflux formula into the simple constraint. The first missing problem is partially solved by the application of this reflux budget constraint, but another problem occurs. The new problem is that infinite expenditure is permitted under this constraint. This is the second missing problem. The second problem appears to be a variation of the solvability problem of the money circulation equation. Referring to the proof of the solvability, we incorporate a time irreversible disposal into the budget constraint. This irreversibility budget constraint brings us a provisional solution of the missing problems. However, it should not be called a perfect solution. We also examine the relationships between our research and two previous studies: the finance constraint and the cash-in-advance model.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 32100400)Huangshan University Startup Project of Scientific Research (2020xkjq013)Environment Conservation Research Centre of Xin’an River Basin (kypt202002)。
文摘Rivers are important habitats for wintering waterbirds.However,they are easily influenced by natural and human activities.An important approach for waterbirds to adapt to habitats is adjusting the activity time and energy expenditure allocation of diurnal behavior.The compensatory foraging hypothesis predicts that increased energy expenditure leads to longer foraging time,which in turn increases food intake and helps maintain a constant energy balance.However,it is unclear whether human-disturbed habitats result in increased energy expenditure related to safety or foraging.In this study,the scan sample method was used to observe the diurnal behavior of the wintering Spot-billed Duck(Anas poecilorhyncha) in two rivers in the Xin’an River Basin from October 2021 to March 2022.The allocation of time and energy expenditure for activity in both normal and disturbed environments was calculated.The results showed that foraging accounted for the highest percentage of time and energy expenditure.Additionally,foraging decreased in the disturbed environment than that in the normal environment.Resting behavior showed the opposite trend,while other behaviors were similar in both environments.The total diurnal energy expenditure of ducks in the disturbed environment was greater than that in the normal environment,with decreased foraging and resting time percentage and increased behaviors related to immediate safety(swimming and alert) and comfort.These results oppose the compensatory foraging hypothesis in favor of increased security.The optimal diurnal energy expenditure model included river width and water depth,which had a positive relationship;an increase in either of these two factors resulted in an increase in energy expenditure.This study provides a better understanding of energy allocation strategies underlying the superficial time allocation of wintering waterbirds according to environmental conditions.Exploring these changes can help understand the maximum fitness of wintering waterbirds in response to nature and h
文摘This paper aims to inquire into an objectively authentic budget constraint in a monetary economy through showing two missing problems of the monetary budget constraint and their solutions. To start with, we show the first missing problem that money is “missing” if all agents expend their total budgets under the simple budget constraint. This problem shows that the simple budget constraint is inadequate as an objective monetary budget constraint. A deficiency of the simple budget constraint exists partly in that it does not reflect money circulation. To improve this deficiency, we incorporate the expenditure reflux formula into the simple constraint. The first missing problem is partially solved by the application of this reflux budget constraint, but another problem occurs. The new problem is that infinite expenditure is permitted under this constraint. This is the second missing problem. The second problem appears to be a variation of the solvability problem of the money circulation equation. Referring to the proof of the solvability, we incorporate a time irreversible disposal into the budget constraint. This irreversibility budget constraint brings us a provisional solution of the missing problems. However, it should not be called a perfect solution. We also examine the relationships between our research and two previous studies: the finance constraint and the cash-in-advance model.
