Multiplexed communication over a high-speed quantum channel

In quantum information systems it is of particular interest to consider the best way in which to use the non-classical resources consumed by that system. Quantum communication protocols are integral to quantum information systems and are amongst the most promising near-term applications of quantum information science. Here we show that a multiplexed, digital quantum communications system supported by comb of vacuum squeezing has a greater channel capacity per photon than a source of broadband squeezing with the same analogue bandwidth. We report on the time-resolved, simultaneous observation of the first dozen teeth in a 2.4 GHz comb of vacuum squeezing produced by a sub-threshold OPO, as required for such a quantum communications channel. We also demonstrate multiplexed communication on that channel

Can optical squeezing be generated via polarization self-rotation in a thermal vapour cell?

The traversal of an elliptically polarized optical field through a thermal vapour cell can give rise to a rotation of its polarization axis. This process, known as polarization self-rotation (PSR), has been suggested as a mechanism for producing squeezed light at atomic transition wavelengths. In this paper, we show results of the characterization of PSR in isotopically enhanced Rubidium-87 cells, performed in two independent laboratories. We observed that, contrary to earlier work, the presence of atomic noise in the thermal vapour overwhelms the observation of squeezing. We present a theory that contains atomic noise terms and show that a null result in squeezing is consistent with this theory.Comment: 10 pages, 11 figures, submitted to PRA. Please email author for a PDF file if the article does not appear properl

Socioeconomic and demographic factors associated with failure in Helicobacter pylori eradication using the standard triple therapy

Aim: To evaluate the influence of socioeconomic and demographic factors on the eradication rate of H. pylori, using standard triple therapy Background: the efficacy of the standard triple therapy (STT) for H. pylori eradication has decreased with the rise of antibiotic resistance. Other factors could influence the eradication failure, although available results are conflicting. Methods: Retrospective study, including adults with H. pylori infection treated de novo with STT (proton pump inhibitor, amoxicillin and clarithromycin). Eradication success was assessed by 13C-urea breath test. Demographic and socioeconomics variables were evaluated and correlated with eradication treatment outcome. The confounder variables were controlled by logistic regression analysis. Results: Out of 902 patients with H. pylori diagnosis, 693 met inclusion criteria (average age 53 years; females 55.2%). Nonsignificant differences were observed in relation to economics income between rural and urban areas (p=0.316). The eradication rate of H. pylori was 71.1%: male 78.9% vs female 65.9%, urban area 73.4% vs rural area 64.1%. With reference to age, income and nationality, the eradication rates were similar in all groups. According to logistic regression analysis, females had almost twice more likelihood of eradication failure in relation to males (OR 1.92; 95%CI: 1.38-2.72); and rural residents had OR 1.55 (95%CI: 1.03- 2.33) for having eradication failure in contrast with urban population. Conclusion: Female gender and rural residence are factors associated with H. Pylori eradication failure with standard triple therapy

“Clip-Stone” Filiation Within the Biliary Tract

A case of cholangitis due to the migration of a metal clip used for surgical cholecystectomy 4 years earlier, is reported. The diagnostic approach and therapeutic options, either endoscopic or surgical are discussed. The use of resorbable clips during the performance of laparoscopic cholecystectomy should avoid this type of complication

Meeting report:Fungal genomics meets social media: Highlights of the 28th fungal genetics conference at asilomar

International audienc

Racial Differences in the Impact of Adolescent Depression on Families in TADS

This manuscript examines racial differences in the impact of adolescent depression between White, African American, and Latino families. Findings are from the Treatment for Adolescents with Depression Study (TADS), a multi-site clinical research study evaluating the efficacy of CBT and Fluoxetine for treating adolescents with major depressive disorder. Primary caretakers of 439 adolescents with depression were interviewed. Results demonstrated that compared to White families, African American and Latino families were more likely to report increased feelings of tiredness or anergia (p\u3c.05) and more physical health problems (p\u3c.01) associated with caring for a depressed teen. The conclusion suggests the need for a better understanding of depression in people and families of color and offers recommendations for further research

An Augmented OxRAM Synapse for Spiking Neural Network (SNN) Circuits

International audienceIn this paper, the conductance modulation of OxRAM memristive devices is evaluated based on experimental data to reveal the memristor inherent analog synaptic behavior. Simulation results are presented to validate the use of OxRAMs as synapses at a circuit level in a spiking neural network context. In the proposed approach, the OxRAM synapse is augmented with a shift register associated with current compliance control transistors to provide an efficient monitoring of the OxRAM conductance

Chandra and Suzaku observations of the Be/X-ray star HD110432

We present an analysis of a pointed 141 ks Chandra high resolution transmission gratings observation of the Be X-ray emitting star HD110432, a prominent member of the gamma Cas analogs. The Chandra lightcurve shows a high variability but its analysis fails to detect any coherent periodicity up to a frequency of 0.05 Hz. The analysis of the Chandra HETG spectrum shows that, to correctly describe the spectrum, three model components are needed. Two of those components are optically thin thermal plasmas of different temperatures (kT~8-9 and 0.2-0.3 keV respectively). Two different models seem to describe well the third component. One possibility is a third hot optically thin thermal plasma at kT=16-21 keV with an Fe abundance Z~0.3Zo, definitely smaller than for the other two thermal components. Alternatively, the third component can be described by a powerlaw with a photon index Gamma=1.56. In either case, the Chandra HETG spectrum establishes that each one of these components must be modified by distinct absorption columns. The analysis of a non contemporaneous 25 ks Suzaku observation shows the presence of a hard tail extending up to at least 33 keV. The Suzaku spectrum is described with the sum of two components: an optically thin thermal plasma at kT ~ 9 keV and a very hot second plasma with kT ~33 keV or, alternatively, a powerlaw with photon index Gamma=1.58. The analysis of the Si XIII and S XV He like triplets present in the Chandra spectrum point to a very dense (n_e ~ 10^13 cm^-3) plasma located either close to the stellar surface (r<3R_*) of the Be star or, alternatively, very close (r ~1.5R_WD) to the surface of a (hypothetical) WD companion. We argue, however, that the available data supports the first scenario.Comment: 13 pages, 21 Figures. Accepted for publication in Ap

Ring closing reaction in diarylethene captured by femtosecond electron crystallography

The photoinduced ring-closing reaction in diarylethene, which serves as a model system for understanding reactive crossings through conical intersections, was directly observed with atomic resolution using femtosecond electron diffraction. Complementary ab initio calculations were also performed. Immediately following photoexcitation, subpicosecond structural changes associated with the formation of an open-ring excited-state intermediate were resolved. The key motion is the rotation of the thiophene rings, which significantly decreases the distance between the reactive carbon atoms prior to ring closing. Subsequently, on the few picosecond time scale, localized torsional motions of the carbon atoms lead to the formation of the closed-ring photoproduct. These direct observations of the molecular motions driving an organic chemical reaction were only made possible through the development of an ultrabright electron source to capture the atomic motions within the limited number of sampling frames and the low data acquisition rate dictated by the intrinsically poor thermal conductivity and limited photoreversibility of organic materials