Nanophotonic soliton-based microwave synthesizers

Microwave photonic technologies, which upshift the carrier into the optical domain to facilitate the generation and processing of ultrawide-band electronic signals at vastly reduced fractional bandwidths, have the potential to achieve superior performance compared to conventional electronics for targeted functions. For microwave photonic applications such as filters, coherent radars, subnoise detection, optical communications and low-noise microwave generation, frequency combs are key building blocks. By virtue of soliton microcombs, frequency combs can now be built using CMOS compatible photonic integrated circuits, operated with low power and noise, and have already been employed in system-level demonstrations. Yet, currently developed photonic integrated microcombs all operate with repetition rates significantly beyond those that conventional electronics can detect and process, compounding their use in microwave photonics. Here we demonstrate integrated soliton microcombs operating in two widely employed microwave bands, X- and K-band. These devices can produce more than 300 comb lines within the 3-dB-bandwidth, and generate microwave signals featuring phase noise levels below 105 dBc/Hz (140 dBc/Hz) at 10 kHz (1 MHz) offset frequency, comparable to modern electronic microwave synthesizers. In addition, the soliton pulse stream can be injection-locked to a microwave signal, enabling actuator-free repetition rate stabilization, tuning and microwave spectral purification, at power levels compatible with silicon-based lasers (<150 mW). Our results establish photonic integrated soliton microcombs as viable integrated low-noise microwave synthesizers. Further, the low repetition rates are critical for future dense WDM channel generation schemes, and can significantly reduce the system complexity of photonic integrated frequency synthesizers and atomic clocks

Slow dynamics and aging in a non-randomly frustrated spin system

A simple, non-disordered spin model has been studied in an effort to understand the origin of the precipitous slowing down of dynamics observed in supercooled liquids approaching the glass transition. A combination of Monte Carlo simulations and exact calculations indicates that this model exhibits an entropy vanishing transition accompanied by a rapid divergence of time scales. Measurements of various correlation functions show that the system displays a hierarchy of time scales associated with different degrees of freedom. Extended structures, arising from the frustration in the system, are identified as the source of the slow dynamics. In the simulations, the system falls out of equilibrium at a temperature $T_{g}$ higher than the entropy-vanishing transition temperature and the dynamics below $T_{g}$ exhibits aging as distinct from coarsening. The cooling rate dependence of the energy is also consistent with the usual glass formation scenario.Comment: 41 pages, 16 figures. Bibliography file is correcte

Laser monitoring system for the CMS lead tungstate crystal calorimeter

We report on the multiple wavelength laser monitoring system designed for the CMS lead tungstate crystal calorimeter read-out with avalanche photodiodes (Barrel calorimeters) and vacuum phototriodes (End Cap calorimeters). Results are presented for the test beam performance of the system designed to achieve 0.5% relative inter-calibration of the optical transmittance for lead tungstate scintillation emission over nearly 80 000 channels. The system operates in continuous measurement cycles to follow each crystal?s evolution under irradiation and recovery periods foreseen during operation at the LHC

Phase noise characterization of sub-hertz linewidth lasers via digital cross correlation

Phase noise or frequency noise is a key metrics to evaluate the short term stability of a laser. This property is of a great interest for the applications but delicate to characterize, especially for narrow line-width lasers. In this letter, we demonstrate a digital cross correlation scheme to characterize the absolute phase noise of sub-hertz line-width lasers. Three 1,542 nm ultra-stable lasers are used in this approach. For each measurement two lasers act as references to characterize a third one. Phase noise power spectral density from 0.5 Hz to 0.8 MHz Fourier frequencies can be derived for each laser by a mere change in the configuration of the lasers. This is the first time showing the phase noise of sub-hertz line-width lasers with no reference limitation. We also present an analysis of the laser phase noise performance.Comment: 4 pages, 5 figure

Management of febrile urinary tract infection among spinal cord injured patients

BACKGROUND: Urinary tract infection (UTI) among patients with neurogenic bladder is a major problem but its management is not well known. We studied the relationship between antibiotic regimen use and the cure rate of those infections among 112 patients with neurogenic bladder. METHODS: We studied a retrospective cohort of febrile UTI among patients with neurogenic bladder. Drug selection was left to the discretion of the treating physicians, in accordance with current guidelines. Patients were divided into 3 groups according to antibiotic treatment duration (<10 days, between 10 and 15 days, and >15 days). We analysed clinical and microbiogical cure rate one month after the end of antibiotic treatment. RESULTS: The three groups of patients were similar, especially in terms of drug treatment (equal distribution). The cure rates were not significantly different (71.4 %, 54.2 %, and 57.1 %, respectively; p = 0.34). Moreover, there was no difference in cure rate between mono and dual therapy (44 % for monotherapy vs. 40 % for dual therapy; p = 0.71). CONCLUSION: This descriptive study supports the efficacy of antimicrobial treatment duration of less than 10 days and the use of monotherapy to treat febrile UTI among patients with neurogenic bladder. A randomized control trial is required to confirm these data

French national cohort of first use of dalbavancin: a high proportion of off-label use

Dalbavancin is a glycopeptide antibiotic with a long half-life, recently marketed in Europe for skin and soft tissue infections (SSTI), but real-life use is not well-known. We aimed to describe all first prescriptions in France over an 18-month period. We performed a retrospective study on all adult patients who received at least one dose of dalbavancin from July 1, 2017 to September 31, 2018. Data were collected thanks to a standard questionnaire. Failure was defined as: persistent or reappearance of signs of infection; and/or switch to suppressive antibiotic treatment; and/or death from infection. We included 75 patients from 29 French hospitals. Main indications were bone and joint infections (BJIs) (64.0%), endocarditis (25.3%), and SSTIs (17.3%). Main bacteria involved were: Staphylococcus aureus (51.4%), including methicillin-resistant S. aureus (MRSA) (19.4%); and coagulase-negative staphylococci (CNS) (44.4%). Median MICs for staphylococci to vancomycin and dalbavancin ranged from 0.875 mg/L to 2.0 mg/L, and 0.040 mg/L to 0.064 mg/L, respectively. Dalbavancin was used after a mean of 2.3 ± 1.2 lines of antimicrobial treatment. Main treatment regimens for dalbavancin were a weekly 2-dose regimen (1500mg each) in 38 (53.2%) cases, and a single-dose regimen (1500mg) in 13 (18.3%) cases. Overall, at the patients\u27 last visit, clinical cure was observed in 54/72 patients, while failure was found in 14/72 patients. First uses of dalbavancin in France were mostly off-label. Most of them were due to BJIs, and often as rescue therapy for severe infections. Even in off-label situations, dalbavancin seems safe and effective

Clinical Study Impact of Anti-Inflammatory Drugs on Pyogenic Vertebral Osteomyelitis: A Prospective Cohort Study

Objective. Pyogenic vertebral osteomyelitis (PVO) are frequently misdiagnosed and patients often receive anti-inflammatory drugs for their back pain. We studied the impact of these medications. Methods. We performed a prospective study enrolling patients with PVO and categorized them depending on their drugs intake. Then, we compared diagnosis delay, clinical presentation at hospitalization, incidence of complications, and cure rate. Results. In total, 79 patients were included. Multivariate analysis found no correlation between anti-inflammatory drug intake and diagnosis delay, clinical presentation, complications, or outcome. Conclusion. Anti-inflammatory drugs intake does not affect diagnostic delay, severity at diagnosis, or complications of PVO

Running of Radiative Neutrino Masses: The Scotogenic Model

We study the renormalization group equations of Ma's scotogenic model, which generates an active neutrino mass at 1-loop level. In addition to other benefits, the main advantage of the mechanism exploited in this model is to lead to a natural loop-suppression of the neutrino mass, and therefore to an explanation for its smallness. However, since the structure of the neutrino mass matrix is altered compared to the ordinary type I seesaw case, the corresponding running is altered as well. We have derived the full set of renormalization group equations for the scotogenic model which, to our knowledge, had not been presented previously in the literature. This set of equations reflects some interesting structural properties of the model, and it is an illustrative example for how the running of neutrino parameters in radiative models is modified compared to models with tree-level mass generation. We also study a simplified numerical example to illustrate some general tendencies of the running. Interestingly, the structure of the RGEs can be exploited such that a bimaximal leptonic mixing pattern at the high-energy scale is translated into a valid mixing pattern at low energies, featuring a large value of \theta_{13}. This suggests very interesting connections to flavour symmetries.Comment: 35 pages, 10 figures, 2 table