Comparison of P and cation cycling in two contrasting seasonally dry forest ecosystems     

Julio Campo  Juan F. Gallardo 《Annals of Forest Science》2012,69(8):887-894

Context

Interactions of N and P cycles and those of other macro-elements in forests are scarcely known.

Aim

This study compares the P cycle in two very different forest ecosystems where soil P availability is low (tropical dry forest in Mexico and Mediterranean forest in Spain) in relation to Ca, K, and Mg cycles.

Methods

Compiled data belonging to these two forest sites are discussed, comparing the P and base cation budgets and exploring relationships among P and base cation cycles.

Results

Broad differences between input and output of base cations were observed. Analysis of the P budget indicates P retention inside both forest ecosystems. The tropical dry forest has higher nutrient contents than those found in the Mediterranean temperate forest. Chemical composition of forest leaves and litters, and base cation?CP ratios varied according to soil P availability and cation concentrations. However, P resorption is higher in the tropical dry forest than in the temperate one.

Conclusion

This study reveals the existence of P retention at the ecosystem level in both forests, but suggested P limitation at the Mediterranean forest seems to be stronger than that occurring at the tropical forest.  相似文献   

Bioequivalence of a new liquid formulation of benazepril compared with the reference tablet product     

K Kelers  JL Devi  GA Anderson  P Zahra  JH Vine  T Whittem 《Australian veterinary journal》2013,91(8):312-319

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Epistaxis in racehorses: risk factors and effects on career     

JL Langford  PC Thomson  PK Knight 《Australian veterinary journal》2013,91(5):198-203

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Bioavailability of two L‐thyroxine formulations after oral administration to healthy dogs     

C Simpson  JL Devi  T Whittem 《Australian veterinary journal》2013,91(3):83-88

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The effects of land abandonment and long‐term afforestation practices on the organic carbon stock and lignin content of Mediterranean humid mountain soils     

Julian Campo  Romy J. Stijsiger  Estela Nadal‐Romero  Erik L.H. Cammeraat 《European Journal of Soil Science》2019,70(5):947-959

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An Association Analysis Between a Silent C558T Polymorphism at the Pig Vascular Cell Adhesion Molecule 1 Locus and Sow Reproduction and Piglet Survivability Traits     

O Ramirez  A Tomàs  J Casellas  M Blanch  JL Noguera  M Amills 《Reproduction in domestic animals》2008,43(5):542-546

The vascular cell adhesion molecule 1 (VCAM1) has a strong influence on embryonic development and on the formation of the umbilical cord and placenta. These developmental processes are crucial to ensure the success of pregnancy. In this work, we have identified two T306A and C558T single nucleotide polymorphisms (SNP) at exons 2 and 3 of the pig VCAM1 locus, respectively. The T306A substitution involves a non conservative Asn to Lys replacement at amino acid position 102, whereas the C558T polymorphism is synonymous. An in silico prediction of the consequences of the Asn₁₀₂→Lys₁₀₂ mutation with the PolyPhen software revealed that it is not deleterious. The T306A SNP segregated in the Iberian, Piétrain, Duroc, Large White and Landrace breeds as well as in European wild boars. The C558T SNP also segregated and most of commercial standard breeds. The genotyping of the C558T SNP in an Iberian × Meishan intercross allowed to find a suggestive association (Bonferroni threshold, p < 0.004) between C558T genotype and time the newborn piglet needs to reach the udder (p = 0.013) as well as a significant one with time to make the first ingestion of colostrum (p = 0.003). The biological basis of these associations remains unclear and they should be interpreted with caution.  相似文献   

Direct measurement of femtomoles of osmium and the 187Os/186Os ratio in seawater     

S Levasseur  JL Birck  CJ Allegre 《Science (New York, N.Y.)》1998,282(5387):272-274

Two depth profiles of the osmium concentration and the 187Os/186Os isotopic ratio in the Indian Ocean showed that the osmium concentration seems to be unaltered by chemical or biological processes occuring in seawater; accordingly, osmium is conservative. These data were obtained from an experimental method that eliminated the problems related to osmium preconcentration. This method led to a new evaluation of the concentration of osmium in seawater; the mean concentration of osmium and the 187Os/186Os ratio are equal to 10.86 +/- 0.07 picograms per kilogram and 8.80 +/- 0.07, respectively. The results suggest the existence of an organocomplex that dominates the speciation of osmium in seawater.  相似文献   

Unconditional quantum teleportation   总被引：5，自引：0，他引：5  

A Furusawa  JL Sorensen  SL Braunstein  CA Fuchs  HJ Kimble  ES Polzik 《Science (New York, N.Y.)》1998,282(5389):706-709

Quantum teleportation of optical coherent states was demonstrated experimentally using squeezed-state entanglement. The quantum nature of the achieved teleportation was verified by the experimentally determined fidelity Fexp = 0.58 +/- 0.02, which describes the match between input and output states. A fidelity greater than 0.5 is not possible for coherent states without the use of entanglement. This is the first realization of unconditional quantum teleportation where every state entering the device is actually teleported.  相似文献   

Femtosecond activation of reactions and the concept of nonergodic molecules     

EWG Diau  JL Herek  ZH Kim  AH Zewail 《Science (New York, N.Y.)》1998,279(5352):847-851

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Tracking the long-term decline and recovery of an isolated population     

RL Westemeier  JD Brawn  SA Simpson  TL Esker  RW Jansen  JW Walk  EL Kershner  JL Bouzat  KN Paige 《Science (New York, N.Y.)》1998,282(5394):1695-1698

Effects of small population size and reduced genetic variation on the viability of wild animal populations remain controversial. During a 35-year study of a remnant population of greater prairie chickens, population size decreased from 2000 individuals in 1962 to fewer than 50 by 1994. Concurrently, both fitness, as measured by fertility and hatching rates of eggs, and genetic diversity declined significantly. Conservation measures initiated in 1992 with translocations of birds from large, genetically diverse populations restored egg viability. Thus, sufficient genetic resources appear to be critical for maintaining populations of greater prairie chickens.  相似文献