1,648 research outputs found
Coherent control of atomic excitation using off-resonant strong few-cycle pulses
We study the dynamics of a two-level system driven by an off-resonant
few-cycle pulse which has a phase jump at , in contrast to many
cycle pulses, under non rotating-wave approximation (NRWA). We give a closed
form analytical solution for the evolution of the probability amplitude for the upper level. Using the appropriate pulse parameters like
phase-jump , jump time , pulse width , frequency and
Rabi frequency the population transfer, after the pulse is gone,
can be optimized and for the pulse considered here, enhancement of
factor was obtained.Comment: 5 Pages, 7 Figure
Correlation between safety attitudes and early adoption of cognitive aids in the German culture sphere: a multicenter survey study
Background: Cognitive Aids (checklists) are a common tool to improve patient safety. But the factors for their successful implementation and continuous use are not yet fully understood. Recent publications suggest safety culture to play a key role in this context. However, the effects on the outcome of implementation measures remain unclear. Hospitals and clinics that are involved in cognitive aid development and research might have significantly different safety cultures than their counterparts, resulting in skewed assessments of proper implementation. Therefore, the objective of this study was to assess the correlation between cognitive aid implementation and safety attitudes of staff members in early adopting and later adopting clinics. Methods: An online survey of the Safety Attitudes Questionnaire (SAQ) was carried out in German anaesthesiology departments during the initial implementation of a new checklist for emergencies during anesthesia (“eGENA” app). Subsequently an analysis between subgroups (“eGENA” app usage and occupation), with Kruskal–Wallis- and Mann–Whitney-U-Tests was carried out for the general SAQ, as well as it six subscales. Results: Departments that introduced “eGENA” app (Median 3,74, IQR 0,90) reported a significantly higher median SAQ (U (NeGENA = 6, Nnon eGENA = 14) = 70,0, z = 2,31, p = 0,02, r = 0,516) than their counterparts (Median 2,82, IQR 0,77) with significant differences in the dimensions teamwork climate, work satisfaction, perception of management and working conditions. Conclusion: Early adopters of cognitive aids are likely to show a significantly higher perception of safety culture in the SAQ. Consequently, successful implementation steps from these settings might not be sufficient in different clinics. Therefore, further investigation of the effects of safety culture on cognitive aid implementation should be conducted
The key position: influence of staple location on constrained peptide conformation and binding
First published online 29 Sep 2016Constrained α-helical peptides are showing potential as biological probes and therapeutic agents that target protein-protein interactions. However, the factors that determine the optimal constraint locations are still largely unknown. Using the β-integrin/talin protein interaction as a model system, we examine the effect of constraint location on helical conformation, as well as binding affinity, using circular dichroism and NMR spectroscopy. Stapling increased the overall helical content of each integrin-based peptide tested. However, NMR analysis revealed that different regions within the peptide are stabilised, depending on constraint location, and that these differences correlate with the changes observed in talin binding mode and affinity. In addition, we show that examination of the atomic structure of the parent peptide provides insight into the appropriate placement of helical constraints.Kelly L. Keeling, Okki Cho, Denis B. Scanlon, Grant W. Booker, Andrew D. Abell and Kate L. Wegene
Evidence for Third-Harmonic Generation in Disguise of Second-Harmonic Generation in Extreme Nonlinear Optics
Verifying proofs in constant depth
In this paper we initiate the study of proof systems where verification of proofs proceeds by NC circuits. We investigate the question which languages admit proof systems in this very restricted model. Formulated alternatively, we ask which languages can be enumerated by NC functions. Our results show that the answer to this problem is not determined by the complexity of the language. On the one hand, we construct NC proof systems for a variety of languages ranging from regular to NP-complete. On the other hand, we show by combinatorial methods that even easy regular languages such as Exact-OR do not admit NC proof systems. We also present a general construction of proof systems for regular languages with strongly connected NFA's
Understanding the dynamics of photoionization-induced solitons in gas-filled hollow-core photonic crystal fibers
We present in detail our developed model [Saleh et al., Phys. Rev. Lett. 107]
that governs pulse propagation in hollow-core photonic crystal fibers filled by
an ionizing gas. By using perturbative methods, we find that the
photoionization process induces the opposite phenomenon of the well-known Raman
self-frequency red-shift of solitons in solid-core glass fibers, as was
recently experimentally demonstrated [Hoelzer et al., Phys. Rev. Lett. 107].
This process is only limited by ionization losses, and leads to a constant
acceleration of solitons in the time domain with a continuous blue-shift in the
frequency domain. By applying the Gagnon-B\'{e}langer gauge transformation,
multi-peak `inverted gravity-like' solitary waves are predicted. We also
demonstrate that the pulse dynamics shows the ejection of solitons during
propagation in such fibers, analogous to what happens in conventional
solid-core fibers. Moreover, unconventional long-range non-local interactions
between temporally distant solitons, unique of gas plasma systems, are
predicted and studied. Finally, the effects of higher-order dispersion
coefficients and the shock operator on the pulse dynamics are investigated,
showing that the resonant radiation in the UV [Joly et al., Phys. Rev. Lett.
106] can be improved via plasma formation.Comment: 9 pages, 10 figure
Wiring up pre-characterized single-photon emitters by laser lithography
Future quantum optical chips will likely be hybrid in nature and include many single-photon emitters, waveguides, filters, as well as single-photon detectors. Here, we introduce a scalable optical localization-selection-lithography procedure for wiring up a large number of single-photon emitters via polymeric photonic wire bonds in three dimensions. First, we localize and characterize nitrogen vacancies in nanodiamonds inside a solid photoresist exhibiting low background fluorescence. Next, without intermediate steps and using the same optical instrument, we perform aligned three-dimensional laser lithography. As a proof of concept, we design, fabricate, and characterize three-dimensional functional waveguide elements on an optical chip. Each element consists of one single-photon emitter centered in a crossed-arc waveguide configuration, allowing for integrated optical excitation and efficient background suppression at the same time
- …