7,618 research outputs found
Blind encoding into qudits
We consider the problem of encoding classical information into unknown qudit
states belonging to any basis, of a maximal set of mutually unbiased bases, by
one party and then decoding by another party who has perfect knowledge of the
basis. Working with qudits of prime dimensions, we point out a no-go theorem
that forbids shift operations on arbitrary unknown states. We then provide the
necessary conditions for reliable encoding/decoding.Comment: To appear in Physics Letters
Back-action cancellation in interferometers by quantum locking
We show that back-action noise in interferometric measurements such as
gravitational-waves detectors can be completely suppressed by a local control
of mirrors motion. An optomechanical sensor with an optimized measurement
strategy is used to monitor mirror displacements. A feedback loop then
eliminates radiation-pressure effects without adding noise. This very efficient
technique leads to an increased sensitivity for the interferometric
measurement, which becomes only limited by phase noise. Back-action
cancellation is furthermore insensitive to losses in the interferometer.Comment: 4 pages, 3 figures, RevTe
Metronomic Chemotherapy with Vinorelbine Produces Clinical Benefit and Low Toxicity in Frail Elderly Patients Affected by Advanced Non-Small Cell Lung Cancer
Lung cancer is the leading cause of death worldwide. The treatment choice for advanced stage of lung cancer may depend on histotype, performance status (PS), age, and comorbidities. In the present study, we focused on the effect of metronomic vinorelbine treatment in elderly patients with advanced unresectable non-small cell lung cancer (NSCLC). Methods. From January 2016 to December 2016, 44 patients affected by non-small cell lung cancer referred to our oncology day hospital were progressively analyzed. The patients were treated with oral vinorelbine 30 mg x 3/wk or 40 mg x 3/wk meaning one day on and one day off. The patients were older than 60, stage IIIB or IV, ECOG PS ≥ 1, and have at least one important comorbidity (renal, hepatic, or cardiovascular disease). The schedule was based on ECOG-PS and comorbidities. The primary endpoint was progression-free survival (PFS). PFS was used to compare patients based on different scheduled dosage (30 or 40 mg x3/weekly) and age (more or less than 75 years old) as exploratory analysis. We also evaluated as secondary endpoint toxicity according to Common Toxicity Criteria Version 2.0. Results. Vinorelbine showed a good safety profile at different doses taken orally and was effective in controlling cancer progression. The median overall survival (OS) was 12 months. The disease control rate (DCR) achieved 63%. The median PFS was 9 months. A significant difference in PFS was detected comparing patients aged below with those over 75, and the HR value was 0.72 (p<0.05). Not significant was the difference between groups with different schedules. Conclusions. This study confirmed the safety profile of metronomic vinorelbine and its applicability for patients unfit for standard chemotherapies and adds the possibility of considering this type of schedule not only for very elderly patients
Motional Squashed States
We show that by using a feedback loop it is possible to reduce the
fluctuations in one quadrature of the vibrational degree of freedom of a
trapped ion below the quantum limit. The stationary state is not a proper
squeezed state, but rather a ``squashed'' state, since the uncertainty in the
orthogonal quadrature, which is larger than the standard quantum limit, is
unaffected by the feedback action.Comment: 8 pages, 2 figures, to appear in the special Issue "Quantum
Correlations and Fluctuations" of J. Opt.
A sustainable two-phase procedure for V-catalyzed toluene oxidative bromination with H2O2–KBr
A sustainable V(V) and Mo(VI) catalysed two-phase procedure for bromination of toluene under quite
mild conditions is proposed; H2O2 is the primary oxidant and KBr is the bromine source; metal precursors
are commercially available salts. The reaction is efficient without any additional solvent. By using PhCH3
as a solvent/substrate good yields, together with interesting selectivity toward the formation of PhCH2Br,
are obtained with both metal ions. Recycling of the catalytic phase is also possible. Useful information on
the V-peroxido chemistry was obtained
Accelerating Bayesian microseismic event location with deep learning
We present a series of new open-source deep-learning algorithms to accelerate Bayesian full-waveform point source inversion of microseismic
events. Inferring the joint posterior probability distribution of moment tensor components and source location is key for rigorous uncertainty
quantification. However, the inference process requires forward modelling of microseismic traces for each set of parameters explored by the sampling
algorithm, which makes the inference very computationally intensive. In this paper we focus on accelerating this process by training deep-learning
models to learn the mapping between source location and seismic traces for a given 3D heterogeneous velocity model and a fixed isotropic moment
tensor for the sources. These trained emulators replace the expensive solution of the elastic wave equation in the inference process.
We compare our results with a previous study that used emulators based on Gaussian processes to invert microseismic events. For fairness of
comparison, we train our emulators on the same microseismic traces and using the same geophysical setting. We show that all of our models provide
more accurate predictions, ∼ 100 times faster predictions than the method based on Gaussian processes, and a (105) speed-up
factor over a pseudo-spectral method for waveform generation. For example, a 2 s long synthetic trace can be generated in ∼ 10 ms on a
common laptop processor, instead of ∼ 1 h using a pseudo-spectral method on a high-profile graphics processing unit card. We also
show that our inference results are in excellent agreement with those obtained from traditional location methods based on travel time estimates. The
speed, accuracy, and scalability of our open-source deep-learning models pave the way for extensions of these emulators to generic source mechanisms
and application to joint Bayesian inversion of moment tensor components and source location using full waveforms.</p
Electron-radiation interaction in a Penning trap: beyond the dipole approximation
We investigate the physics of a single trapped electron interacting with a
radiation field without the dipole approximation. This gives new physical
insights in the so-called geonium theory.Comment: 12 pages, RevTeX, 6 figures, Approved for publication in Phys. Rev.
Stochastic resonance in Gaussian quantum channels
We determine conditions for the presence of stochastic resonance in a lossy
bosonic channel with a nonlinear, threshold decoding. The stochastic resonance
effect occurs if and only if the detection threshold is outside of a "forbidden
interval". We show that it takes place in different settings: when transmitting
classical messages through a lossy bosonic channel, when transmitting over an
entanglement-assisted lossy bosonic channel, and when discriminating channels
with different loss parameters. Moreover, we consider a setting in which
stochastic resonance occurs in the transmission of a qubit over a lossy bosonic
channel with a particular encoding and decoding. In all cases, we assume the
addition of Gaussian noise to the signal and show that it does not matter who,
between sender and receiver, introduces such a noise. Remarkably, different
results are obtained when considering a setting for private communication. In
this case the symmetry between sender and receiver is broken and the "forbidden
interval" may vanish, leading to the occurrence of stochastic resonance effects
for any value of the detection threshold.Comment: 17 pages, 6 figures. Manuscript improved in many ways. New results on
private communication adde
Looking back to see the future: building nuclear power plants in Europe
The so-called ‘nuclear renaissance’ in Europe is promulgated by the execution of two large engineering projects involving the construction of two European Pressurized Reactors (EPRs) in Flamanville, France and Olkiluoto in Finland. As both projects have faced budget overruns and delays, this paper analyses their governance and history to derive lessons useful for the construction of future projects. Analysis indicates that the reasons for these poor outcomes are: overoptimistic estimations, first-of-a-kind (FOAK) issues and undervaluation of regulation requirements. These pitfalls have the potential to impact on many other engineering construction projects and highlight fruitful areas of further research into project performance
Celebrating Economies of Change: Brave Visions for Inclusive Futures
This issue has been inspired by a path-breaking conference held by the Canadian Society for Ecologi-cal Economics (CANSEE), which took place this past May 2019 in Waterloo, Ontario. Entitled Engaging Economies of Change, the conference aimed to ex-pand existing research networks in the economy-environment nexus by building connections beyond the academy in order to meaningfully engage with the practicalities of building and implementing change. This issue captures the rich content shared during the event, as well as descriptions of the pro-cesses and efforts made to create a welcoming and respectful space where academics and community activists could build alliances and discuss common challenges. The conference organizers – all graduate students and activists themselves -- called this ‘building a brave space’.This research was supported by the Social Sciences and Humanities Research Council of Canad
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