373 research outputs found

    Magnetic quantum critical point and superconductivity in UPt3 doped with Pd

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    Transverse-field muon spin relaxation measurements have been carried out on the heavy-fermion superconductor UPt3 doped with small amounts of Pd. We find that the critical Pd concentration for the emergence of the large-moment antiferromagnetic phase is ~0.6 at.%Pd. At the same Pd content, superconductivity is completely suppressed. The existence of a magnetic quantum critical point in the phase diagram, which coincides with the critical point for superconductivity, provides evidence for ferromagnetic spin-fluctuation mediated odd-parity superconductivity, which competes with antiferromagnetic order.Comment: 4 pages (includes 3 figures); postscript fil

    Magnetic quantum critical point and superconductivity in UPt3 doped with Pd

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    Transverse-field muon spin relaxation measurements have been carried out on the heavy-fermion superconductor UPt3 doped with small amounts of Pd. We find that the critical Pd concentration for the emergence of the large-moment antiferromagnetic phase is ~0.6 at.%Pd. At the same Pd content, superconductivity is completely suppressed. The existence of a magnetic quantum critical point in the phase diagram, which coincides with the critical point for superconductivity, provides evidence for ferromagnetic spin-fluctuation mediated odd-parity superconductivity, which competes with antiferromagnetic order.Comment: 4 pages (includes 3 figures); postscript fil

    Magnetism in heavy-fermion U(Pt,Pd)3 studied by mSR

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    We report mSR experiments carried out on a series of heavy-electron pseudobinary compounds U(Pt1-xPdx)3 (x<=0.05). For x<=0.005 the zero-field muon depolarisation is described by the Kubo-Toyabe function. However the temperature variation of the Kubo-Toyabe relaxation rate does not show any sign of the small-moment antiferromagnetic phase with TN~6 K (signalled by neutron diffraction), in contrast to previous reports. The failure to detect the small ordered moment suggests it has a fluctuating (> 10 MHz) nature, which is consistent with the interpretation of NMR data. For 0.01<=x<=0.05 the muon depolarisation in the ordered state is described by two terms of equal amplitude: an exponentially damped spontaneous oscillation and a Lorentzian Kubo-Toyabe function. These terms are associated with antiferromagnetic order with substantial moments. The Knight-shift measured in a magnetic field of 0.6 T on single-crystalline U(Pt0.95Pd0.05)3 in the paramagnetic state shows two signals for B perpendicular to c, while only one signal is observed for B||c. The observation of two signals for B perpendicular to c, while there is only one muon localisation site (0,0,0), points to the presence of two spatially distinct regions of different magnetic response.Comment: 25 pages including 12 figures (PS), J. Phys.: Condens. Matter, in prin

    A New Method for Finishing Minicavities

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    Minicavities were prepared in 26 caries-free teeth. Cavity preparation and the finishing of the occlusal area and the gingival floor was done with diamond burs (diameter 1 mm, grain sizes 90 ÎŒm and 15 ÎŒm, respectively). For the finishing of the axial box margin and the proximo-cervicaI curved border, a new set was developed: It is composed of an EVA-system with the total amplitude reduced to 0.34 mm, and a highly flexible file (Cavishape, grain 15 ÎŒm). The shape of this file had to be modified in order to follow the proximo-cervical curvature. The efficiency of the new device was compared with the axial margin trimmer by means of scanning electron microscopy and a score system. The new device allowed a significantly better finishing of the proximo-cervical curvature and of the axial box margin

    Fully flexible analysis of behavioural sequences based on parametric survival models with frailties—A tutorial

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    Recent automated systems allow collecting continuous data on individual animals with high accuracy over a long time. During this time, animals can be traced across different (discrete) types of behavioural states, with the duration in each state being known. Nevertheless, analyses of such sequences of states or behaviours may prove difficult. Classic Markov-chain methods have limitations in respect to incorporating “memory” (effects of past states), the duration in the states and accounting for dependencies. Dependencies occur in many data sets, where, for example a variety of individuals from different groups are observed and/or when an experiment is divided in different crossover treatment phases. So-called parametric survival analysis with frailties can incorporate aforementioned aspects in one coherent model. The time spent in a specific state (performing a specific behaviour) can be modelled in dependence of the subsequent state (transition probabilities) while incorporating how these transitions are influenced by experimental treatments. In addition, prior states can be used as predictor variables (accounting for past behaviour). Finally, random effects can be included to account for dependencies according to, for example individual identity, group/farm/laboratory or experimental period. Using interactions between random and fixed effects, the within- and between-subject variability of the transition probabilities can be estimated to indicate variation between and consistency within individual subjects (individuality and personality). Moreover, relative hazards describing transitions from one state to several potential follow-up states can be estimated. Behavioural sequences and their modulation by experimental situations can be studied accordingly. Using two exemplary data sets, the data type and structure adequate for parametric survival analysis are introduced and advice is given on how to specify and run such models. Overall, parametric survival analysis with frailties presents a modern and versatile approach that can revive sequential analysis. This will facilitate more detailed use of behavioural data and accordingly detect more subtle aspects of behaviour.Ministerie van Economische Zaken en Klimaat http://dx.doi.org/10.13039/501100016238Bundesamt fĂŒr Lebensmittelsicherheit und VeterinĂ€rwesen http://dx.doi.org/10.13039/501100006454Peer Reviewe

    IMAPlate Based Miniature, High Sensitive, Rapid Screening Method for Detecting Bioengineered, Secreted Lipase Activities in Yeast Expression Systems

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    A spectrophotometric assay based on a miniaturized 96-well plate device (IMAPlate) enables a rapid and simple screening of bioengineered recombinant lipases expressed and secreted by Saccharomyces cerevisiae. Starting from a colony, the test delivers a quantitative estimation of enzymatic activity titer in 24 h or less with manual high throughput performances

    Muon localization site in U(Pt,Pd)3

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    The angular and temperature (10-250 K) variation of the Knight shift of single-crystalline U(Pt0.95Pd0.05)3 has been measured in transverse field (B=0.6 T) mSR experiments. By analysing the temperature variation of the Knight shift with a modified Curie-Weiss expression the muon localization site in this hexagonal material is determined at (0,0,0).Comment: 12 pages (including 4 figures); postscript file; Proc. 8th Int. Conf. on Muon Spin Rotation, Relaxation and Resonance (Aug.30-Sept.3, Les Diablerets); 2nd version with minor correction

    Molecular markers linked to the apple scab resistance gene Vbj derived from Malus baccata jackii

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    Breeding for scab-resistant apple cultivars by pyramiding several resistance genes in the same genetic background is a promising way to control apple scab caused by the fungus Venturia inaequalis. To achieve this goal, DNA markers linked to the genes of interest are required in order to select seedlings with the desired resistance allele combinations. For several apple scab resistance genes, molecular markers are already available; but until now, none existed for the apple scab resistance gene Vbj originating from the crab apple Malus baccata jackii. Using bulk segregant analysis, three RAPD markers linked to Vbj were first identified. These markers were transformed into more reliable sequence-characterised amplified region (SCAR) markers that proved to be co-dominant. In addition, three SSR markers and one SCAR were identified by comparing homologous linkage groups of existing genetic maps. Discarding plants showing genotype-phenotype incongruence (GPI plants) plants, a linkage map was calculated. Vbj mapped between the markers CH05e03 (SSR) and T6-SCAR, at 0.6cM from CH05e03 and at 3.9cM from T6-SCAR. Without the removal of the GPI plants, Vbj was placed 15cM away from the closest markers. Problems and pitfalls due to GPI plants and the consequences for mapping the resistance gene accurately are discussed. Finally, the usefulness of co-dominant markers for pedigree analysis is also demonstrate

    Characterization of a submillimeter high-angular-resolution camera with a monolithic silicon bolometer array for the Caltech Submillimeter Observatory

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    We constructed a 24-pixel bolometer camera operating in the 350- and 450-”m atmospheric windows for the Caltech Submillimeter Observatory (CSO). This instrument uses a monolithic silicon bolometer array that is cooled to approximately 300 mK by a single-shot 3 He refrigerator. First-stage amplification is provided by field-effect transistors at approximately 130 K. The sky is imaged onto the bolometer array by means of several mirrors outside the Dewar and a cold off-axis elliptical mirror inside the cryostat. The beam is defined by cold aperture and field stops, which eliminates the need for any condensing horns. We describe the instrument, present measurements of the physical properties of the bolometer array, describe the performance of the electronics and the data-acquisition system, and demonstrate the sensitivity of the instrument operating at the observatory. Approximate detector noise at 350 ”m is 5 x 10^-15 W/√Hz, referenced to the entrance of the Dewar, and the CSO system noise-equivalent flux density is approximately 4 Jy/√Hz. These values are within a factor of 2.5 of the background limit
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