798 research outputs found
Strongly driven quantum pendulum of the OCS molecule
We demonstrate and analyze a strongly driven quantum pendulum in the angular
motion of stateselected and laser aligned OCS molecules. Raman-couplings during
the rising edge of a 50-picosecond laser pulse create a wave packet of pendular
states, which propagates in the confining potential formed by the
polarizability interaction between the molecule and the laser field. This
wave-packet dynamics manifests itself as pronounced oscillations in the degree
of alignment with a laser-intensity dependent period.Comment: 6 pages, 4 figure
A coalgebraic treatment of conditional transition systems with upgrades
We consider conditional transition systems, that model software product lines with upgrades, in a coalgebraic setting. By using Birkhoff's duality for distributive lattices, we derive two equivalent Kleisli categories in which these coalgebras live: Kleisli categories based on the reader and on the so-called lattice monad over Poset. We study two different functors describing the branching type of the coalgebra and investigate the resulting behavioural equivalence. Furthermore we show how an existing algorithm for coalgebra minimisation can be instantiated to derive behavioural equivalences in this setting
Emission of volatile halogenated compounds, speciation and localization of bromine and iodine in the brown algal genome model Ectocarpus siliculosus
This study explores key features of bromine and iodine metabolism in the filamentous brown alga and genomics model Ectocarpus siliculosus. Both elements are accumulated in Ectocarpus, albeit at much lower concentration factors (2-3 orders of magnitude for iodine, and < 1 order of magnitude for bromine) than e.g. in the kelp Laminaria digitata. Iodide competitively reduces the accumulation of bromide. Both iodide and bromide are accumulated in the cell wall (apoplast) of Ectocarpus, with minor amounts of bromine also detectable in the cytosol. Ectocarpus emits a range of volatile halogenated compounds, the most prominent of which by far is methyl iodide. Interestingly, biosynthesis of this compound cannot be accounted for by vanadium haloperoxidase since the latter have not been found to catalyze direct halogenation of an unactivated methyl group or hydrocarbon so a methyl halide transferase-type production mechanism is proposed
Single-photon-emitting optical centers in diamond fabricated upon Sn implantation
The fabrication of luminescent defects in single-crystal diamond upon Sn
implantation and annealing is reported. The relevant spectral features of the
optical centers (emission peaks at 593.5 nm, 620.3 nm, 630.7 nm and 646.7 nm)
are attributed to Sn-related defects through the correlation of their
photoluminescence (PL) intensity with the implantation fluence. Single
Sn-related defects were identified and characterized through the acquisition of
their second-order auto-correlation emission functions, by means of
Hanbury-Brown-Twiss interferometry. The investigation of their single-photon
emission regime as a function of excitation laser power revealed that
Sn-related defects are based on three-level systems with a 6 ns radiative decay
lifetime. In a fraction of the studied centers, the observation of a blinking
PL emission is indicative of the existence of a dark state. Furthermore,
absorption dependence from the polarization of the excitation radiation with
about 45 percent contrast was measured. This work shed light on the existence
of a new optical center associated with a group-IV impurity in diamond, with
similar photo-physical properties to the already well-known Si-V and Ge-V
emitters, thus providing results of interest from both the fundamental and
applicative points of view.Comment: 10 pages, 4 figure
Management of female genital mutilation / cutting-related obstetric complications: a training evaluation
Although female genital mutilation/cutting (FGM/C) is a prevalent practice in Liberia, healthcare workers lack the capacity to provide adequate care for FGM/C survivors. Therefore, Liberian nurses, physician assistants, midwives and trained traditional midwives were trained in sexual, obstetric and psychosocial care for FGM/C survivors in 2019. Through questionnaires, we assessed knowledge acquisition, trainee attitudes towards FGM/C care and acceptability to implement WHO-endorsed recommendations. The questionnaires were analyzed using descriptive statistics for quantitative data and an inductive approach for qualitative data. A total of 99 female and 34 male trainees participated. Most trainees perceived FGM/C as harmful to women''s health, as a violation of women''s rights and showed a willingness to change their clinical practice. While 82.8% (n = 74/90) perceived their role in advocating against FGM/C, 10.0% (n = 9/90) felt that they should train traditional circumcisers to practice FGM/C safely. The pre-training FGM/C knowledge test demonstrated higher scores among physician assistants (13.86 ± 3.02 points) than among nurses (12.11 ± 3.12 points) and midwives (11.75 ± 2.27 points). After the training, the mean test score increased by 1.69 points, from 12.18 (±2.91) points to 13.87 (±2.65) points. The trainings successfully increased theoretical knowledge of FGM/C-caused health effects and healthcare workers'' demonstrated willingness to implement evidence-based guidelines when providing care to FMG/C survivors
Major Breeding Plumage Color Differences of Male Ruffs (Philomachus pugnax) Are Not Associated With Coding Sequence Variation in the MC1R Gene.
Sequence variation in the melanocortin-1 receptor (MC1R) gene explains color morph variation in several species of birds and mammals. Ruffs (Philomachus pugnax) exhibit major dark/light color differences in melanin-based male breeding plumage which is closely associated with alternative reproductive behavior. A previous study identified a microsatellite marker (Ppu020) near the MC1R locus associated with the presence/absence of ornamental plumage. We investigated whether coding sequence variation in the MC1R gene explains major dark/light plumage color variation and/or the presence/absence of ornamental plumage in ruffs. Among 821bp of the MC1R coding region from 44 male ruffs we found 3 single nucleotide polymorphisms, representing 1 nonsynonymous and 2 synonymous amino acid substitutions. None were associated with major dark/light color differences or the presence/absence of ornamental plumage. At all amino acid sites known to be functionally important in other avian species with dark/light plumage color variation, ruffs were either monomorphic or the shared polymorphism did not coincide with color morph. Neither ornamental plumage color differences nor the presence/absence of ornamental plumage in ruffs are likely to be caused entirely by amino acid variation within the coding regions of the MC1R locus. Regulatory elements and structural variation at other loci may be involved in melanin expression and contribute to the extreme plumage polymorphism observed in this species
Production and deceleration of a pulsed beam of metastable NH () radicals
We report on the production of a pulsed molecular beam of metastable NH () radicals and present first results on the Stark deceleration of the
NH () radicals from 550 m/s to 330 m/s. The
decelerated molecules are excited on the spin-forbidden transition, and detected via their subsequent spontaneous
fluorescence to the ground-state. These experiments
demonstrate the feasibility of our recently proposed scheme [Phys. Rev. A 64
(2001) 041401] to accumulate ground-state NH radicals in a magnetic trap.Comment: 11 pages, 4 figures, v2: fixed author name for web-abstract, no
changes to manuscrip
Optimizing the Stark-decelerator beamline for the trapping of cold molecules using evolutionary strategies
We demonstrate feedback control optimization for the Stark deceleration and
trapping of neutral polar molecules using evolutionary strategies. In a
Stark-decelerator beamline pulsed electric fields are used to decelerate OH
radicals and subsequently store them in an electrostatic trap. The efficiency
of the deceleration and trapping process is determined by the exact timings of
the applied electric field pulses. Automated optimization of these timings
yields an increase of 40 % of the number of trapped OH radicals.Comment: 7 pages, 4 figures (RevTeX) (v2) minor corrections (v3) no changes to
manuscript, but fix author list in arXiv abstrac
Coupled-mode equations and gap solitons in a two-dimensional nonlinear elliptic problem with a separable periodic potential
We address a two-dimensional nonlinear elliptic problem with a
finite-amplitude periodic potential. For a class of separable symmetric
potentials, we study the bifurcation of the first band gap in the spectrum of
the linear Schr\"{o}dinger operator and the relevant coupled-mode equations to
describe this bifurcation. The coupled-mode equations are derived by the
rigorous analysis based on the Fourier--Bloch decomposition and the Implicit
Function Theorem in the space of bounded continuous functions vanishing at
infinity. Persistence of reversible localized solutions, called gap solitons,
beyond the coupled-mode equations is proved under a non-degeneracy assumption
on the kernel of the linearization operator. Various branches of reversible
localized solutions are classified numerically in the framework of the
coupled-mode equations and convergence of the approximation error is verified.
Error estimates on the time-dependent solutions of the Gross--Pitaevskii
equation and the coupled-mode equations are obtained for a finite-time
interval.Comment: 32 pages, 16 figure
Addressing a real‐life problem: treatment with intravenous thrombolysis and mechanical thrombectomy in acute stroke patients with an extended time window beyond 4.5 h based on computed tomography perfusion imaging
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