Results 61 to 70 of about 23,991 (132)

Alleviation of phosphorus rather than nitrogen limitation driven by permafrost and landscape effects on Dahurian larch forests

open access: yesFunctional Ecology, Volume 40, Issue 8, Page 2590-2601, August 2026.
Read the free Plain Language Summary for this article on the Journal blog. Abstract Permafrost thaw is reshaping nutrient dynamics in boreal forests, but its impacts on tree nutrient limitation and functional strategies remain poorly understood. Clarifying these responses is crucial for predicting the response of boreal forests to climate change.
Qiyue Fu   +9 more
wiley   +1 more source

Pinus armandii ectomycorrhizas mobilize aluminium‐bound phosphorus via carboxylates along a subtropical altitudinal gradient

open access: yesJournal of Ecology, Volume 114, Issue 8, August 2026.
Ectomycorrhizal roots of Pinus armandii release more carboxylates than non‐mycorrhizal root segments, mobilizing Al‐bound inorganic P. Under the lowest available P conditions, they also secrete more phosphatase, promoting the mineralization of Al‐bound organic P.
Jun Zhou   +7 more
wiley   +1 more source

关于一个单位分数的问题

open access: yes四川大学学报. 自然科学版, 1984
把5/121表成三个单位分数的和,即求方程 5/121=1/x+1/y+1/z的正整数解问题,Blericher得到一组解为(x,y,z)=(25,759,208725)。但是,Bleri-cher不知道三项展开式能否具有一个小于208725的最大分母,这个问题容易解决。看来更有意义的问题是:(1)是否有max(x,y,z)>208725的解。本文得到(1)的全部解共21组,其中max(x,y,z)>208725的解一组。从而解决了以上问题。
刘元章
doaj  

Regulatory compliance and support for altered management of the exotic pet trade

open access: yesConservation Biology, Volume 40, Issue 4, August 2026.
Abstract Globally, the exotic pet trade has contributed to species invasion, disease, and animal welfare risks. Although scientists have advocated for increased trade regulation, the success of management and regulatory efforts depends on compliance by participants in the exotic pet trade. We used a regulatory compliance framework to investigate exotic
Elizabeth N. Pratt   +3 more
wiley   +1 more source

具有时滞的周期Lotka-Volterra系统的持久性与渐进稳定性(英文)

open access: yes四川大学学报. 自然科学版, 2004
研究了具有反馈的Lotka Volterra方程,给出了其正解具有持久性的充分条件.并利用Horn不动点定理,得到其正周期解的存在性.
曾永福, 徐道义
doaj  

Using customs data to understand overlooked trade in non‐CITES birds between Africa and Asia

open access: yesConservation Biology, Volume 40, Issue 4, August 2026.
Abstract The international trade in live birds poses risks to animals, people, and biodiversity. To effectively mitigate these risks, decision‐makers require information on the volume, dynamics, and direction of trade. Despite Africa once being the largest exporter of birds by region, very little data exist on recent trade in live birds not listed on ...
Alisa Davies   +4 more
wiley   +1 more source

Providing regular and frequent maps of losses and gains of farmland birds based on European monitoring data

open access: yesConservation Biology, Volume 40, Issue 4, August 2026.
Abstract Knowledge of species distributions is essential for informing policies on nature conservation and restoration. However, updating them on a regular basis and doing so in a harmonized manner at the international level is difficult. The European Bird Census Council integrated national monitoring data covering 5 years to update farmland bird ...
Sergi Herrando   +54 more
wiley   +1 more source

关于丢番都方程(a2-b2x+(2ab)v=(a2+b22

open access: yes四川大学学报. 自然科学版, 1959
除x=y=z=2外,有无其他正整数解。Jesmanowicz的猜测是没有其他正整数解。并且证明了对于b,a=2,3;3,4;4,5;5,6,他的猜测是成立的。作者曾对a=n+1,b=n,其中n为自然数时得出了一些结果 ...
柯召
doaj  

Centering geospatial data uncertainty and the potential for injustice in pastoralist rangeland conservation prioritization

open access: yesConservation Biology, Volume 40, Issue 4, August 2026.
Abstract Procedural, distributional, recognitional, and epistemic justice aspects of conservation interventions are well documented in contexts where pastoralism is a key livelihood and way of life. Geospatial analyses and representations of wildlife conservation and restoration that are increasingly applied in pastoralist rangeland socioecological ...
Ryan R. Unks
wiley   +1 more source

一类含一阶导数的二阶三点边值问题的可解性

open access: yes四川大学学报. 自然科学版, 2008
利用积分方程,作者通过构造适当的Banach空间考察了一类含有一阶导数的二阶三点边值问题的解和正解的存在性.利用Leray-Schauder不动点定理,作者证明了只要非线性项在其定义域的某个有界子集上的"高度"是适当的则该类问题可以有一个解或者正解.
姚庆六
doaj  

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