1,250 research outputs found

    Multispecies genetic objectives in spatial conservation planning.

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    The growing threats to biodiversity and global alteration of habitats and species distributions make it increasingly necessary to consider evolutionary patterns in conservation decision-making. Yet there is no clear-cut guidance on how genetic features can be incorporated into conservation planning processes, with multiple molecular markers and several genetic metrics for each marker type to choose from. Genetic patterns also differ between species, but the potential trade-offs amongst genetic objectives for multiple species in conservation planning are currently understudied. This study compares spatial conservation prioritizations derived from two metrics of both genetic diversity (nucleotide and haplotype diversity) and genetic isolation (private haplotypes and local genetic differentiation) for mitochondrial DNA for five marine species. The findings show that conservation plans based solely on habitat representation noticeably differ from those additionally including genetic data, with habitat-based conservation plans selecting fewer conservation priority areas. Furthermore, all four genetic metrics selected approximately similar conservation priority areas, which is likely a result of prioritizing genetic patterns across a genetically diverse array of species. Largely, the results suggest that multi-species genetic conservation objectives are vital to create protected area networks that appropriately preserve community-level evolutionary patterns. This article is protected by copyright. All rights reserved

    Gas valves, forests and global change: a commentary on Jarvis (1976) 'The interpretation of the variations in leaf water potential and stomatal conductance found in canopies in the field'.

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    Microscopic turgor-operated gas valves on leaf surfaces-stomata-facilitate gas exchange between the plant and the atmosphere, and respond to multiple environmental and endogenous cues. Collectively, stomatal activities affect everything from the productivity of forests, grasslands and crops to biophysical feedbacks between land surface vegetation and climate. In 1976, plant physiologist Paul Jarvis reported an empirical model describing stomatal responses to key environmental and plant conditions that predicted the flux of water vapour from leaves into the surrounding atmosphere. Subsequent theoretical advances, building on this earlier approach, established the current paradigm for capturing the physiological behaviour of stomata that became incorporated into sophisticated models of land carbon cycling. However, these models struggle to accurately predict observed trends in the physiological responses of Northern Hemisphere forests to recent atmospheric CO2 increases, highlighting the need for improved representation of the role of stomata in regulating forest-climate interactions. Bridging this gap between observations and theory as atmospheric CO2 rises and climate change accelerates creates challenging opportunities for the next generation of physiologists to advance planetary ecology and climate science. This commentary was written to celebrate the 350th anniversary of the journal Philosophical Transactions of the Royal Society

    General Form of the Color Potential Produced by Color Charges of the Quark

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    Constant electric charge ee satisfies the continuity equation ∂ΌjÎŒ(x)=0\partial_\mu j^{\mu}(x)= 0 where jÎŒ(x)j^\mu(x) is the current density of the electron. However, the Yang-Mills color current density jÎŒa(x)j^{\mu a}(x) of the quark satisfies the equation DÎŒ[A]jÎŒa(x)=0D_\mu[A] j^{\mu a}(x)= 0 which is not a continuity equation (∂ΌjÎŒa(x)≠0\partial_\mu j^{\mu a}(x)\neq 0) which implies that a color charge qa(t)q^a(t) of the quark is not constant but it is time dependent where a=1,2,...8a=1,2,...8 are color indices. In this paper we derive general form of color potential produced by color charges of the quark. We find that the general form of the color potential produced by the color charges of the quark at rest is given by \Phi^a(x) =A_0^a(t,{\bf x}) =\frac{q^b(t-\frac{r}{c})}{r}\[\frac{{\rm exp}[g\int dr \frac{Q(t-\frac{r}{c})}{r}] -1}{g \int dr \frac{Q(t-\frac{r}{c})}{r}}\]_{ab} where drdr integration is an indefinite integration, ~~ Qab(τ0)=fabdqd(τ0)Q_{ab}(\tau_0)=f^{abd}q^d(\tau_0), ~~r=∣x⃗−X⃗(τ0)∣r=|{\vec x}-{\vec X}(\tau_0)|, ~~τ0=t−rc\tau_0=t-\frac{r}{c} is the retarded time, ~~cc is the speed of light, ~~X⃗(τ0){\vec X}(\tau_0) is the position of the quark at the retarded time and the repeated color indices b,db,d(=1,2,...8) are summed. For constant color charge qaq^a we reproduce the Coulomb-like potential Ίa(x)=qar\Phi^a(x)=\frac{q^a}{r} which is consistent with the Maxwell theory where constant electric charge ee produces the Coulomb potential Ί(x)=er\Phi(x)=\frac{e}{r}.Comment: Final version, two more sections added, 45 pages latex, accepted for publication in JHE
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