Coherent dynamics of a single spin interacting with an adjustable spin bath     

Hanson R  Dobrovitski VV  Feiguin AE  Gywat O  Awschalom DD 《Science (New York, N.Y.)》2008,320(5874):352-355

Phase coherence is a fundamental concept in quantum mechanics. Understanding the loss of coherence is paramount for future quantum information processing. We studied the coherent dynamics of a single central spin (a nitrogen-vacancy center) coupled to a bath of spins (nitrogen impurities) in diamond. Our experiments show that both the internal interactions of the bath and the coupling between the central spin and the bath can be tuned in situ, allowing access to regimes with surprisingly different behavior. The observed dynamics are well explained by analytics and numerical simulations, leading to valuable insight into the loss of coherence in spin systems. These measurements demonstrate that spins in diamond provide an excellent test bed for models and protocols in quantum information.  相似文献   

Large scale measurements     

Hanson B  Voss D 《Science (New York, N.Y.)》1992,256(5055):289

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Intellectual Excitement: The "New" versus the "Classical"     

Hanson ED 《Science (New York, N.Y.)》1963,142(3593):623

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Reviewing peer review     

Alberts B  Hanson B  Kelner KL 《Science (New York, N.Y.)》2008,321(5885):15

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Agriculture. Transforming U.S. agriculture     

Reganold JP  Jackson-Smith D  Batie SS  Harwood RR  Kornegay JL  Bucks D  Flora CB  Hanson JC  Jury WA  Meyer D  Schumacher A  Sehmsdorf H  Shennan C  Thrupp LA  Willis P 《Science (New York, N.Y.)》2011,332(6030):670-671

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Hyperkalemic periodic paralysis and the adult muscle sodium channel alpha-subunit gene   总被引：22，自引：0，他引：22  

B Fontaine  T S Khurana  E P Hoffman  G A Bruns  J L Haines  J A Trofatter  M P Hanson  J Rich  H McFarlane  D M Yasek 《Science (New York, N.Y.)》1990,250(4983):1000-1002

Hyperkalemic periodic paralysis (HYPP) is an autosomal dominant disorder characterized by episodes of muscle weakness due to depolarization of the muscle cell membrane associated with elevated serum potassium. Electrophysiological studies have implicated the adult muscle sodium channel. Here, portions of the adult muscle sodium channel alpha-subunit gene were cloned and mapped near the human growth hormone locus (GH1) on chromosome 17. In a large pedigree displaying HYPP with myotonia, these two loci showed tight linkage to the genetic defect with no recombinants detected. Thus, it is likely that the sodium channel alpha-subunit gene contains the HYPP mutation.  相似文献   

Characterisation of germplasm accessions of Napier grass (pennisetum purpureum and P. purpureum×P. glaucum Hybrids) and comparison with farm clones using RAPD     

A.J. Lowe  W. Thorpe  A. Teale  J. Hanson 《Genetic Resources and Crop Evolution》2003,50(2):121-132

Fifty six germplasm accessions of the important East African fodder crop Napier grass, Pennisetum purpureum, and its hybrids with P. glaucum, were characterised using 67 random amplified polymorphic DNA (RAPD) fragments. No or very low intra-accession variation was found for 49 of the accessions examined, confirming field observations that this species is predominantly clonally propagated. Comparison of intra and inter-accession variation identified several groups of identical/similar accessions that could be targeted if the collection is to be rationalised, and also highlighted two misplantings of germplasm material during transfer to a field trial site. A neighbour joining dendrogram of Jaccard's similarity estimates, clearly separated 50 accessions of P. purpureum from three P. glaucum individuals, and placed six hybrid accessions in an intermediate position. These groupings were well supported by a nested AMOVA (P<0.001; 29.5% of total variance due to taxonomic delineation). The main group of P. purpureum individuals could be further differentiated into five sub-groups (designated East Africa, Southern Africa, USA1, USA2 and Miscellaneous, to reflect the majority membership of sub-groups) and examination of the within P. purpureum component of the nested AMOVA, found them to be significantly different (P<0.001; 18.8% of variance). Genetic diversity across all accessions was found to be fairly high (Shannon's diversity index 0.306) and thus the collection probably represents a wide genetic base for this species. In addition to germplasm accessions, 25 Kenyan farm clones were also analysed. A principal coordinate analysis found that all but one of the clones clustered with the main P. purpureum group of accessions, indicating that the majority are probably not interspecific hybrids. The origin and pedigree of clones is discussed based on genetic similarity amongst clones and to germplasm accessions.  相似文献   

Forest responses to CO2 enrichment and climate warming     

R. J. Luxmoore  S. D. Wullschleger  P. J. Hanson 《Water, air, and soil pollution》1993,70(1-4):309-323

Two of the major uncertainties in forecasting future terrestrial sources and sinks of CO₂ are the CO₂-enhanced growth response of forests and soil warming effects on net CO₂ efflux from forests. Carbon dioxide enrichment of tree seedlings over time periods less than 1 yr has generally resulted in enhanced rates of photosynthesis, decreased respiration, and increased growth, with minor increases in leaf area and small changes in C allocation. Exposure of woody species to elevated CO₂ over several years has shown that high rates of photosynthesis may be sustained, but net C accumulation may not necessarily increase if CO₂ release from soil respiration increases. The impact of the 25% rise in atmospheric CO₂ with industrialization has been examined in tree ring chronologies from a range of species and locations. In contrast to the seedling tree results, there is no convincing evidence for CO₂-enhanced stem growth of mature trees during the last several decades. However, if mature trees show a preferential root growth response to CO₂ enrichment, the gain in root mass for an oak-hickory forest in eastern Tennessee is estimated to be only 9% over the last 40 years. Root data bases are inadequate for detecting such an effect. A very small shift in ecosystem nutrients from soil to vegetation could support CO₂-enhanced growth. Climate warming and the accompanying increase in mean soil temperature could have a greater effect than CO₂ enrichment on terrestrial sources and sinks of CO₂. Soil respiration and N mineralization have been shown to increase with soil temperature. If plant growth increases with increased N availability, and more C is fixed in growth than is released by soil respiration, then a negative feedback on climate warming will occur. If warming results in a net increase in CO₂ efflux from forests, then a positive feedback will follow. A 2 to 4°C increase in soil temperature could increase CO₂ efflux from soil by 15 to 32% in eastern deciduous forests. Quantifying C budget responses of forests to future global change scenarios will be speculative until mature tree responses to CO₂ enrichment and the effects of temperature on terrestrial sources and sinks of CO₂ can be determined.  相似文献   

Influence of temperature on induction by Newcastle disease virus of polykaryocytes in garter snake cells     

L Melendez  J Spalatin  R P Hanson 《American journal of veterinary research》1965,26(115):1451-1456

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Laryngotracheitis in show chickens     

D N Tripathy  L E Hanson 《Avian diseases》1981,25(3):756-757

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