Long-distance free-space distribution of quantum entanglement   总被引：1，自引：0，他引：1  

Aspelmeyer M  Böhm HR  Gyatso T  Jennewein T  Kaltenbaek R  Lindenthal M  Molina-Terriza G  Poppe A  Resch K  Taraba M  Ursin R  Walther P  Zeilinger A 《Science (New York, N.Y.)》2003,301(5633):621-623

We demonstrate the distribution of quantum entanglement via optical free-space links to independent receivers separated by 600 m, with no line of sight between each other. A Bell inequality between those receivers is violated by more than four standard deviations, confirming the quality of the entanglement. This outdoor experiment represents a step toward satellite-based distributed quantum entanglement.  相似文献   

Transition state stabilization by a catalytic RNA     

Rupert PB  Massey AP  Sigurdsson ST  Ferré-D'Amaré AR 《Science (New York, N.Y.)》2002,298(5597):1421-1424

The hairpin ribozyme catalyzes sequence-specific cleavage of RNA through transesterification of the scissile phosphate. Vanadate has previously been used as a transition state mimic of protein enzymes that catalyze the same reaction. Comparison of the 2.2 angstrom resolution structure of a vanadate-hairpin ribozyme complex with structures of precursor and product complexes reveals a rigid active site that makes more hydrogen bonds to the transition state than to the precursor or product. Because of the paucity of RNA functional groups capable of general acid-base or electrostatic catalysis, transition state stabilization is likely to be an important catalytic strategy for ribozymes.  相似文献   

Fine silt and clay mineralogical changes of a soil chronosequence in the Langtang valley (Central Nepal)     

Rupert Bumler  Dhruba P. Madhikermi  Wolfgang Zech 《植物养料与土壤学杂志》1997,160(3):413-421

Chemical and mineralogical properties of a soil chronosequence in the high mountain zone between 3857 m and 4120 m a.s.l. in Central Nepal (Langtang valley) are presented. The soils have been developed in moraine deposits which consist of acid gneisses. They were classified as Entisols, and Spodosols. XRD analyses of the clay and fine silt fraction show increasing changes with distance from the recent Lirung glacier, depending on the time of deposition, resp. soil age. Alteration of illite to interstratified minerals and to hydroxy-Al interlayered minerals or pedogenic chlorite with increasing soil development could be observed. The interstratified minerals could be identified as random and regular illite-interlayered vermiculite mixed-layer minerals. Intensification of the X-ray signals of the fine silt fraction is given compared to the clay. With increasing soil development differences between the clay and fine silt fraction seem to increase. Indications are given of interstratification of the mica-pedogenic chlorite and chloriteinterlayered vermiculite type in the more intensively weathered soils.  相似文献   

Implementation of a computer simulation swine tactical decision, support model in Prince Edward Island.   总被引：1，自引：0，他引：1       下载免费PDF全文

J E Alsop  J B Rafuse  I R Keith  W Koopman  A W Jalvingh    I R Dohoo 《The Canadian veterinary journal. La revue veterinaire canadienne》1994,35(3):153-157

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Pathogenicity and virulence of south African isolates of Venturia inaequalis     

Koopman  T. A.  Meitz-Hopkins  J. C.  Tobutt  K. R.  Bester  C.  Lennox  C. L. 《European journal of plant pathology / European Foundation for Plant Pathology》2022,162(1):45-61

European Journal of Plant Pathology - Many abiotic and biotic factors can negatively affect the production and productivity of coconut cropping systems. The incidence of Lasiodiplodia species in...  相似文献   

Simulation of a real-time process adaptation in the manufacture of high-density fibreboards using multivariate regression analysis and feedforward control     

Martin Riegler  Bernhard Spangl  Martin Weigl  Rupert Wimmer  Ulrich Müller 《Wood Science and Technology》2013,47(6):1243-1259

The industrial manufacturing of wood-based panels has become a highly technological process, where all parameters have to be perfectly adjusted to manufacture products of high quality. However, variations caused by differing wood characteristics as well as variations of single process parameters can cause out-of-control events. These undesirable events can be diminished by monitoring and controlling the entire manufacturing process using multivariate statistical techniques. Hence, a real-time process adaptation of an industrial scale fibreboard manufacturing process was simulated. Regression results revealed a mean normalised root mean squared error of prediction of 4.6 %, when predicting the internal bond strength of fibreboards. The regression model is regularly validated and, if necessary, recalibrated using the offline determined board properties (feedback control). Consequently, the process can immediately be adapted as soon as the board is produced (feedforward control). The investigations resulted in reliable models and revealed high potential for permanent industrial implementation.  相似文献   

Protection of chicks against salmonella infection induced by spray application of intestinal microflora in the hatchery     

E. Goren  W. A. de Jong  P. Doornenbal  J. P. Koopman  H. M. Kennis 《The Veterinary quarterly》2013,33(2):73-79

Summary

The efficacy of spray application of intestinal microflora of the adult bird in protection of broilers against salmonella infections was studied in 3 experiments under laboratory and field conditions.

In chicks treated soon after hatching (in the hatchers at approximately 30 per cent hatch or in the chick delivery boxes in the hatchery) with crop‐caecum homogenate or a mixture of aerobically and strict anaerobically cultured intestinal flora, very good results were achieved.

A very obvious protective effect against a high infection dose (3 × 10 c.f.u. S. infantis bacteria per chick) and complete protection against natural infection with different salmonella types was induced.

A significant improvement of growth rate was observed in broilers treated by spray in the hatchery and reared for 7 weeks under field conditions in an environment heavily contaminated with different salmonella types.  相似文献   

Adapting the innovation systems approach to agricultural development in Vietnam: challenges to the public extension service     

Rupert Friederichsen  Thai Thi Minh  Andreas Neef  Volker Hoffmann 《Agriculture and Human Values》2013,30(4):555-568

Competing models of innovation informing agricultural extension, such as transfer of technology, participatory extension and technology development, and innovation systems have been proposed over the last decades. These approaches are often presented as antagonistic or even mutually exclusive. This article shows how practitioners in a rural innovation system draw on different aspects of all three models, while creating a distinct local practice and discourse. We revisit and deepen the critique of Vietnam’s “model” approach to upland rural development, voiced a decade ago in this journal. Our analysis of interviews with grassroots extension workers and extension managers reveals how they have received government, donor, and academic discourses on participation, user-orientation, and private sector involvement in innovation. Extension workers as well as managers integrate the reform discourses into the still-dominant transfer of technology model. We show how extensionists draw selectively on these diverse discourses to foster interaction with outsiders and clients, and bolster their livelihood strategies. We conclude that the conceptual framework suggested by the innovation systems (IS) approach is broadly appropriate for analyzing the Vietnamese case, but that the IS approach in the contemporary Vietnamese context requires adaptation for taking into account the blurred line between private and state sectors, and recognizing the hegemonic position of state-based networks. Improving extensionists’ ability to mediate between the conflicting principles of farmers’ self-organization and government control is identified as a key challenge for increasing innovative capacity in rural upland Vietnam.  相似文献   

Genetic variation among <Emphasis Type="Italic">Fusarium</Emphasis> isolates from onion,and resistance to <Emphasis Type="Italic">Fusarium</Emphasis> basal rot in related <Emphasis Type="Italic">Allium</Emphasis> species   总被引：2，自引：0，他引：2  

Guillermo A. Galván  Carole F. S. Koning-Boucoiran  Wim J. M. Koopman  Karin Burger-Meijer  Pablo H. González  Cees Waalwijk  Chris Kik  Olga E. Scholten 《European journal of plant pathology / European Foundation for Plant Pathology》2008,121(4):499-512

The aim of this research was to study levels of resistance to Fusarium basal rot in onion cultivars and related Allium species, by using genetically different Fusarium isolates. In order to select genetically different isolates for disease testing, a collection of 61 Fusarium isolates, 43 of them from onion (Allium cepa), was analysed using amplified fragment length polymorphism (AFLP) markers. Onion isolates were collected in The Netherlands (15 isolates) and Uruguay (9 isolates), and received from other countries and fungal collections (19 isolates). From these isolates, 29 were identified as F. oxysporum, 10 as F. proliferatum, whereas the remaining four isolates belonged to F. avenaceum and F. culmorum. The taxonomic status of the species was confirmed by morphological examination, by DNA sequencing of the elongation factor 1-α gene, and by the use of species-specific primers for Fusarium oxysporum, F. proliferatum, and F. culmorum. Within F. oxysporum, isolates clustered in two clades suggesting different origins of F. oxysporum forms pathogenic to onion. These clades were present in each sampled region. Onion and six related Allium species were screened for resistance to Fusarium basal rot using one F. oxysporum isolate from each clade, and one F. proliferatum isolate. High levels of resistance to each isolate were found in Allium fistulosum and A. schoenoprasum accessions, whereas A. pskemense, A. roylei and A. galanthum showed intermediate levels of resistance. Among five A. cepa cultivars, ‘Rossa Savonese’ was also intermediately resistant. Regarding the current feasibility for introgression, A. fistulosum, A. roylei and A. galanthum were identified as potential sources for the transfer of resistance to Fusarium into onion.  相似文献   

A method to monitor airborne Venturia inaequalis ascospores using volumetric spore traps and quantitative PCR     

J. C. Meitz-Hopkins  S. G. von Diest  T. A. Koopman  A. Bahramisharif  C. L. Lennox 《European journal of plant pathology / European Foundation for Plant Pathology》2014,140(3):527-541

Apple scab caused by the fungus Venturia inaequalis can result in significant crop losses if not managed effectively. Sanitation as part of an integrated management strategy aims to significantly reduce primary inoculum to lower the disease pressure. This study evaluates the possibility of molecular detection and quantification of ascospore discharge and the use of this method to test for efficacy of orchard sanitation treatments. A method to detect and quantify airborne ascospores was developed using volumetric spore traps (VSTs). V. inaequalis specific primers were tested on daily VST samples from two orchard sections (leaf litter removed compared to leaf litter left) during spring. A molecular method to detect and quantify ascospores was tested by amplifying genomic regions of the mitochondrial CYP51A1 gene, and the ITS region using SYBR® green. Timing of ascospore discharge was compared to predicted infection risk and a degree day model using weather data. The average spore detection limit was estimated to be at levels of 1 pg μl^?1 DNA (approximately 37 ascospores) per daily spore trap reading using CYP51A1 primers. Using the CYP51A1 primer pair, primary inoculum was estimated to be 51 % lower in the orchard sections where leaves had been removed, indicating that this method could be used to evaluate the efficacy of alternative control strategies such as leaf removal to reduce potential ascospore dose. This is the first report of combining VSTs and quantitative PCR to monitor airborne V. inaequalis ascospores.  相似文献