83 research outputs found
Tuning the Gap of a Superconducting Flux Qubit
We experimentally demonstrate the in situ tunability of the minimum energy
splitting (gap) of a superconducting flux qubit by means of an additional flux
loop. Pulses applied via a local control line allow us to tune the gap over a
range of several GHz on a nanosecond timescale. The strong flux sensitivity of
the gap (up to 0.7 GHz/mPhi_0) opens up the possibility to create different
types of tunable couplings that are effective at the degeneracy point of the
qubit. We investigate the dependence of the relaxation time and the Rabi
frequency on the qubit gap.Comment: submitted to PRL, 4 pages, 5 figure
Spectroscopy on two coupled flux qubits
We have performed spectroscopy measurements on two coupled flux qubits. The
qubits are coupled inductively, which results in a
interaction. By applying microwave radiation, we observe resonances due to
transitions from the ground state to the first two excited states. From the
position of these resonances as a function of the magnetic field applied we
observe the coupling of the qubits. The coupling strength agrees well with
calculations of the mutual inductance
Critical Exponents of the Classical 3D Heisenberg Model: A Single-Cluster Monte Carlo Study
We have simulated the three-dimensional Heisenberg model on simple cubic
lattices, using the single-cluster Monte Carlo update algorithm. The expected
pronounced reduction of critical slowing down at the phase transition is
verified. This allows simulations on significantly larger lattices than in
previous studies and consequently a better control over systematic errors. In
one set of simulations we employ the usual finite-size scaling methods to
compute the critical exponents from a few
measurements in the vicinity of the critical point, making extensive use of
histogram reweighting and optimization techniques. In another set of
simulations we report measurements of improved estimators for the spatial
correlation length and the susceptibility in the high-temperature phase,
obtained on lattices with up to spins. This enables us to compute
independent estimates of and from power-law fits of their
critical divergencies.Comment: 33 pages, 12 figures (not included, available on request). Preprint
FUB-HEP 19/92, HLRZ 77/92, September 199
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The influence of the accessory genome on bacterial pathogen evolution
Bacterial pathogens exhibit significant variation in their genomic content of virulence factors. This reflects the abundance of strategies pathogens evolved to infect host organisms by suppressing host immunity. Molecular arms-races have been a strong driving force for the evolution of pathogenicity, with pathogens often encoding overlapping or redundant functions, such as type III protein secretion effectors and hosts encoding ever more sophisticated immune systems. The pathogens’ frequent exposure to other microbes, either in their host or in the environment, provides opportunities for the acquisition or interchange of mobile genetic elements. These DNA elements accessorise the core genome and can play major roles in shaping genome structure and altering the complement of virulence factors. Here, we review the different mobile genetic elements focusing on the more recent discoveries and highlighting their role in shaping bacterial pathogen evolution
Epidemiology of nausea and vomiting of pregnancy: prevalence, severity, determinants, and the importance of race/ethnicity
<p>Abstract</p> <p>Background</p> <p>Studies that contributed to the epidemiology of nausea and vomiting of pregnancy have reported conflicting findings, and often failed to account for all possible co-variables necessary to evaluate the multidimensional associations. The objectives of this study were to: 1) Estimate the prevalence and the severity of nausea and vomiting of pregnancy during the 1<sup>st </sup>and the 2<sup>nd </sup>trimester of pregnancy, and 2) Identify determinants of presence and severity of nausea and vomiting of pregnancy during the 1<sup>st </sup>and 2<sup>nd </sup>trimesters separately, with a special emphasis on the impact of race/ethnicity.</p> <p>Methods</p> <p>A prospective study including pregnant women attending the Centre Hospitalier Universitaire (CHU) Sainte-Justine or René-Laennec clinics for their prenatal care was conducted from 2004 to 2006. Women were eligible if they were ≥ 18 years of age, and ≤ 16 weeks of gestation. Women were asked to fill out a 1<sup>st </sup>trimester self-administered questionnaire and were interviewed over the telephone during their 2<sup>nd </sup>trimester of pregnancy. Presence of nausea and vomiting of pregnancy was based on the reporting of pregnant women (yes/no); severity of symptoms was measured by the validated modified-PUQE index.</p> <p>Results</p> <p>Of the 367 women included in the study, 81.2% were Caucasians, 10.1% Blacks, 4.6% Hispanics, and 4.1% Asians. Multivariate analyses showed that race/ethnicity was significantly associated with a decreased likelihood of reporting nausea and vomiting of pregnancy (Asians vs. Caucasians OR: 0.13; 95%CI 0.02–0.73; and Blacks vs. Caucasians OR: 0.29; 95%CI 0.09–0.99).</p> <p>Conclusion</p> <p>Our study showed that race/ethnicity was associated with the reporting of nausea and vomiting of pregnancy in the 1<sup>st </sup>trimester of pregnancy.</p
Evaluation of phosphorus in forest soils: Comparison of phosphorus uptake, extraction method and soil properties
Phosphorus in soils from plantation of red pine ( Pinus resinosa Ait.) was determined using six extractants: 0.002 N H 2 SO 4 (pH 3.0); 0.025 N HCl+ +0.03 N NH 4 F; 0.5 N NaHCO 3 (pH 8.5); N NH 4 OAc (pH 4.8); anion exchange resin (Dower −2, Cl-form); H 2 O. Correlations of extractable P with Al- and Al-+Fe-P indicated that these fractions are the dominant forms of inorganic P in most of the soils.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43473/1/11104_2005_Article_BF02149737.pd
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