Heat Equilibration of Integer and Fractional Quantum Hall Edge Modes in Graphene.

Hole-conjugate states of the fractional quantum Hall effect host counterpropagating edge channels which are thought to exchange charge and energy. These exchanges have been the subject of extensive theoretical and experimental works; in particular, it is yet unclear if the presence of integer quantum Hall edge channels stemming from fully filled Landau levels affects heat equilibration along the edge. In this Letter, we present heat transport measurements in quantum Hall states of graphene demonstrating that the integer channels can strongly equilibrate with the fractional ones, leading to markedly different regimes of quantized heat transport that depend on edge electrostatics. Our results allow for a better comprehension of the complex edge physics in the fractional quantum Hall regime.

Quantum Hall Valley Splitters and a Tunable Mach-Zehnder Interferometer in Graphene.

Graphene is a very promising test bed for the field of electron quantum optics. However, a fully tunable and coherent electronic beam splitter is still missing. We report the demonstration of electronic beam splitters in graphene that couple quantum Hall edge channels having opposite valley polarizations. The electronic transmission of our beam splitters can be tuned from zero to near unity. By independently setting the beam splitters at the two corners of a graphene p-n junction to intermediate transmissions, we realize a fully tunable electronic Mach-Zehnder interferometer. This tunability allows us to unambiguously identify the quantum interferences due to the Mach-Zehnder interferometer, and to study their dependence with the beam-splitter transmission and the interferometer bias voltage. The comparison with conventional semiconductor interferometers points toward universal processes driving the quantum decoherence in those two different 2D systems, with graphene being much more robust to their effect.

Myasthenia gravis and pregnancy.

Myasthenia gravis is an autoimmune disease characterised by fluctuating muscle weakness, which worsens during activity. It affects particularly scapular and pelvic girdles, axial and bulbar muscles. Myasthenia gravis is twice more frequent in women and symptoms often appear in the second and third decade of life. Thus, a growing number of women affected by this condition become pregnant. To minimise the effects of myasthenia gravis on pregnancy and the newborn, and to avoid myasthenia crisis in the post-partum, the pregnancy must be planned as far as possible. During pregnancy, treatment must be reviewed due to the threat of teratogenic effects (mycophenolate mofetil, rituximab), and the follow-up must be multidisciplinary.

A snapshot of European neurosurgery December 2019 vs. March 2020: just before and during the Covid-19 pandemic.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 or Covid-19), which began as an epidemic in China and spread globally as a pandemic, has necessitated resource management to meet emergency needs of Covid-19 patients and other emergent cases. We have conducted a survey to analyze caseload and measures to adapt indications for a perception of crisis. METHODS: We constructed a questionnaire to survey a snapshot of neurosurgical activity, resources, and indications during 1 week with usual activity in December 2019 and 1 week during SARS-CoV-2 pandemic in March 2020. The questionnaire was sent to 34 neurosurgical departments in Europe; 25 departments returned responses within 5 days. RESULTS: We found unexpectedly large differences in resources and indications already before the pandemic. Differences were also large in how much practice and resources changed during the pandemic. Neurosurgical beds and neuro-intensive care beds were significantly decreased from December 2019 to March 2020. The utilization of resources decreased via less demand for care of brain injuries and subarachnoid hemorrhage, postponing surgery and changed surgical indications as a method of rationing resources. Twenty departments (80%) reduced activity extensively, and the same proportion stated that they were no longer able to provide care according to legitimate medical needs. CONCLUSION: Neurosurgical centers responded swiftly and effectively to a sudden decrease of neurosurgical capacity due to relocation of resources to pandemic care. The pandemic led to rationing of neurosurgical care in 80% of responding centers. We saw a relation between resources before the pandemic and ability to uphold neurosurgical services. The observation of extensive differences of available beds provided an opportunity to show how resources that had been restricted already under normal conditions translated to rationing of care that may not be acceptable to the public of seemingly affluent European countries.

Antibunched Photons Emitted by a dc-Biased Josephson Junction.

We show experimentally that a dc biased Josephson junction in series with a high-enough-impedance microwave resonator emits antibunched photons. Our resonator is made of a simple microfabricated spiral coil that resonates at 4.4 GHz and reaches a 1.97 kΩ characteristic impedance. The second order correlation function of the power leaking out of the resonator drops down to 0.3 at zero delay, which demonstrates the antibunching of the photons emitted by the circuit at a rate of 6×10^{7} photons per second. Results are found in quantitative agreement with our theoretical predictions. This simple scheme could offer an efficient and bright single-photon source in the microwave domain.

Minimal-excitation states for electron quantum optics using levitons.

The on-demand generation of pure quantum excitations is important for the operation of quantum systems, but it is particularly difficult for a system of fermions. This is because any perturbation affects all states below the Fermi energy, resulting in a complex superposition of particle and hole excitations. However, it was predicted nearly 20 years ago that a Lorentzian time-dependent potential with quantized flux generates a minimal excitation with only one particle and no hole. Here we report that such quasiparticles (hereafter termed levitons) can be generated on demand in a conductor by applying voltage pulses to a contact. Partitioning the excitations with an electronic beam splitter generates a current noise that we use to measure their number. Minimal-excitation states are observed for Lorentzian pulses, whereas for other pulse shapes there are significant contributions from holes. Further identification of levitons is provided in the energy domain with shot-noise spectroscopy, and in the time domain with electronic Hong-Ou-Mandel noise correlations. The latter, obtained by colliding synchronized levitons on a beam splitter, exemplifies the potential use of levitons for quantum information: using linear electron quantum optics in ballistic conductors, it is possible to imagine flying-qubit operation in which the Fermi statistics are exploited to entangle synchronized electrons emitted by distinct sources. Compared with electron sources based on quantum dots, the generation of levitons does not require delicate nanolithography, considerably simplifying the circuitry for scalability. Levitons are not limited to carrying a single charge, and so in a broader context n-particle levitons could find application in the study of full electron counting statistics. But they can also carry a fraction of charge if they are implemented in Luttinger liquids or in fractional quantum Hall edge channels; this allows the study of Abelian and non-Abelian quasiparticles in the time domain. Finally, the generation technique could be applied to cold atomic gases, leading to the possibility of atomic levitons.

Strongly Correlated Charge Transport in Silicon Metal-Oxide-Semiconductor Field-Effect Transistor Quantum Dots.

Quantum shot noise probes the dynamics of charge transfers through a quantum conductor, reflecting whether quasiparticles flow across the conductor in a steady stream, or in syncopated bursts. We have performed high-sensitivity shot noise measurements in a quantum dot obtained in a silicon metal-oxide-semiconductor field-effect transistor. The quality of our device allows us to precisely associate the different transport regimes and their statistics with the internal state of the quantum dot. In particular, we report on large current fluctuations in the inelastic cotunneling regime, corresponding to different highly correlated, non-Markovian charge transfer processes. We have also observed unusually large current fluctuations at low energy in the elastic cotunneling regime, the origin of which remains to be fully investigated.

Erratum: Fluctuation-Dissipation Relations of a Tunnel Junction Driven by a Quantum Circuit [Phys. Rev. Lett. 114, 126801 (2015)].

This corrects the article DOI: 10.1103/PhysRevLett.114.126801.

Emission of Nonclassical Radiation by Inelastic Cooper Pair Tunneling.

We show that a properly dc-biased Josephson junction in series with two microwave resonators of different frequencies emits photon pairs in the resonators. By measuring auto- and intercorrelations of the power leaking out of the resonators, we demonstrate two-mode amplitude squeezing below the classical limit. This nonclassical microwave light emission is found to be in quantitative agreement with our theoretical predictions, up to an emission rate of 2 billion photon pairs per second.

Fluctuation-dissipation relations of a tunnel junction driven by a quantum circuit.

We derive fluctuation-dissipation relations for a tunnel junction driven through a resonator displaying strong quantum fluctuations. We find that the fluctuation-dissipation relations derived for classical external drives hold, provided the effect of the circuit's quantum fluctuations is incorporated into the modified nonlinear current voltage characteristics. We also demonstrate that all quantities measured under a time dependent bias can be reconstructed from their values measured under a dc bias using photoassisted tunneling relations. We confirm these predictions by implementing the circuit and measuring the dc current through the junction, its high frequency admittance, and its current noise at the frequency of the resonator.

Molecular revolution in the diagnosis of microbial brain abscesses.

A brain abscess is a life-threatening infection, frequently with serious sequelae. Culture-based methods present many limitations and do not enable an exhaustive documentation of the bacterial flora. 16S rRNA-based amplification, cloning, and high-throughput sequencing have dramatically increased the number of identified agents of brain abscesses, showing that the causative flora is polymicrobial in up to 40 % of cases, with the presence of at least one anaerobic bacterium. In contrast, real-time polymerase chain reaction (PCR) technology is an appealing alternative to culture-based methods for diagnosing brain abscesses due to its speed, sensitivity, and specificity. Molecular typing is available for several bacterial and fungal genera, and this user-friendly tool is accessible for the clinical microbiology laboratory to diagnose microbes involved in a brain abscess. This article reviews the applications of the currently available tools for the etiological diagnosis of a brain abscess.

Sensorial and fatty acid profile of ice cream manufactured with milk of crossbred cows fed palm oil and coconut fat.

This work was carried out to study the nutritional quality of milk of cows fed palm oil (PAL) or coconut fat (COC), and the use of that milk as raw material for ice cream production. Three treatments were tested with 23 healthy cows: control (CON), PAL, and COC. The milk was collected at d 21 and 36 of the experimental diet. Proximate composition (moisture, ash, fat, protein, and carbohydrates) and fatty acid composition were evaluated on milk and ice cream, and sensorial analysis, color (lightness, green/red, and blue/yellow), overrun, and texture were evaluated on the ice cream. Fatty acids present in milk and ice cream were determined by gas chromatography. Sensory analysis results showed that the ice cream acceptability index was above 70%. No difference was observed for proximate composition in milk and ice cream. Chromatographic analysis showed an increase in saturated fatty acid concentration in CON and lower levels in PAL; polyunsaturated fatty acid concentration was higher in PAL and lower in CON, in milk and ice cream; monounsaturated fatty acid concentration in milk was higher in PAL and lower in CON but no difference was found in ice cream. Comparing n-3 content in milk and ice cream, we observed that PAL had higher levels than CON and COC. The results indicate that it is feasible to add sources of fat to the animal feed for fatty acid composition modulation of milk and ice cream.

[Update of the 2013 consensus conference "Management of the preoperative risk of infection"]. / Mise à jour 2013 de la conférence de consensus « Gestion préopératoire du risque infectieux ¼

UNLABELLED: The surgical site infections (SSI) are rare adverse events that may have severe consequences in terms of morbidity, mortality and costs. Guidelines on the preparation of the patient can reduce the risk of SSI. Previous guidelines were published in 2004. MATERIAL: A steering committee and a group of experts were established after seeking professional societies that had participated in the previous guidelines. The working group has defined the objectives of revising and retained two main themes: skin preparation and nasal decolonization of patients with Staphylococcus aureus. We chose to report only the work done on the patient skin preparation. The working group relied on the method of recommendation for clinical practice of the High Authority for Health (HAS). The GRADE approach was used to analyze the articles published since 2004. RESULTS: It is recommended to perform a preoperative shower but when does not matter. The use of a simple soap seems sufficient. Shampoo does not seem essential nor removal of varnish in the field of urology. Impregnated fabrics, adhesives fields and bacteriological insulating films are of little use to reduce the risk of infection. The depilation is not routinely required. It is recommended to perform a cleansing on contaminated skin. The use of an alcohol antiseptic is preferred, the successive application of two different antiseptics range is possible. CONCLUSIONS: The updated guidelines on the patient skin preparation before urological surgery was necessary. It changed some guidelines that should appear in our daily practice.

Carrier drift velocity and edge magnetoplasmons in graphene.

We investigate electron dynamics at the graphene edge by studying the propagation of collective edge magnetoplasmon excitations. By timing the travel of narrow wave packets on picosecond time scales around exfoliated samples, we find chiral propagation with low attenuation at a velocity that is quantized on Hall plateaus. We extract the carrier drift contribution from the edge magnetoplasmon propagation and find it to be slightly less than the Fermi velocity, as expected for an abrupt edge. We also extract the characteristic length for Coulomb interaction at the edge and find it to be smaller than that for soft depletion-edge systems.

Guillain-Barré syndrome following severe head trauma and spine surgery.

Guillain-Barré syndrome (GBS) is an acute-onset inflammatory polyradiculoneuropathy usually triggered by an infectious disease. In some cases, GBS can occur without any preceding infectious episode, like after vaccination, epidural anaesthesia or surgery. A 73 years old woman had head and spine trauma. Body-TDM showed bilateral temporal and right frontal haematomas and fracture of the first lumbar vertebrae. Sextant and kyphoplasty were performed. She presented 14 days after surgery tetraparesis, swallowing difficulties and bilateral facial palsy. Electromyography was consistent with demyelinating neuropathy. Cerebrospinal fluid examination found albumino-cytological dissociation. Viral and bacterial serology and antiganglioside antibodies were negative. She was treated with intravenous immunoglobulins. Four months after discharge she had fully recovered except left peripheral facial palsy. GBS can rarely be triggered by head trauma or spine surgery. Physician must keep in mind this diagnosis whenever their patients present acute-onset neurological worsening in such context.

Process design for wastewater treatment: catalytic ozonation of organic pollutants.

Emerging micropollutants have been recently the target of interest for their potential harmful effects in the environment and their resistance to conventional water treatments. Catalytic ozonation is an advanced oxidation process consisting of the formation of highly reactive radicals from the decomposition of ozone promoted by a catalyst. Nanocarbon materials have been shown to be effective catalysts for this process, either in powder form or grown on the surface of a monolithic structure. In this work, carbon nanofibers grown on the surface of a cordierite honeycomb monolith are tested as catalyst for the ozonation of five selected micropollutants: atrazine (ATZ), bezafibrate, erythromycin, metolachlor, and nonylphenol. The process is tested both in laboratorial and real conditions. Later on, ATZ was selected as a target pollutant to further investigate the role of the catalytic material. It is shown that the inclusion of a catalyst improves the mineralization degree compared to single ozonation.

Through the orbit and beyond: Current state and future perspectives in endoscopic orbital surgery on behalf of the EANS frontiers committee in orbital tumors and the EANS skull base section.

Introduction: Orbital surgery has always been disputed among specialists, mainly neurosurgeons, otorhinolaryngologists, maxillofacial surgeons and ophthalmologists. The orbit is a borderland between intra- and extracranial compartments; Krönlein's lateral orbitotomy and the orbitozygomatic infratemporal approach are the historical milestones of modern orbital-cranial surgery. Research question: Since its first implementation, endoscopy has significantly impacted neurosurgery, changing perspectives and approaches to the skull base. Since its first application in 2009, transorbital endoscopic surgery opened the way for new surgical scenario, previously feasible only with extensive tissue dissection. Material and methods: A PRISMA based literature search was performed to select the most relevant papers on the topic. Results: Here, we provide a narrative review on the current state and future trends in endoscopic orbital surgery. Discussion and conclusion: This manuscript is a joint effort of the EANS frontiers committee in orbital tumors and the EANS skull base section.

Quantum coherence engineering in the integer quantum Hall regime.

We present an experiment where the quantum coherence in the edge states of the integer quantum Hall regime is tuned with a decoupling gate. The coherence length is determined by measuring the visibility of quantum interferences in a Mach-Zehnder interferometer as a function of temperature, in the quantum Hall regime at a filling factor 2. The temperature dependence of the coherence length can be varied by a factor of 2. The strengthening of the phase coherence at finite temperature is shown to arise from a reduction of the coupling between copropagating edge states. This opens the way for a strong improvement of the phase coherence of quantum Hall systems. The decoupling gate also allows us to investigate how interedge state coupling influences the quantum interferences' dependence on the injection bias. We find that the finite bias visibility can be decomposed into two contributions: a Gaussian envelope which is surprisingly insensitive to the coupling, and a beating component which, on the contrary, is strongly affected by the coupling.