A significant problem for current quantum computers is noise. While there are many distinct noise channels, the depolarizing noise model often appropriately describes average noise for large circuits ...involving many qubits and gates. We present a method to mitigate the depolarizing noise by first estimating its rate with a noise-estimation circuit and then correcting the output of the target circuit using the estimated rate. The method is experimentally validated on a simulation of the Heisenberg model. We find that our approach in combination with readout-error correction, randomized compiling, and zero-noise extrapolation produces close to exact results even for circuits containing hundreds of CNOT gates. We also show analytically that zero-noise extrapolation is improved when it is applied to the output of our method.
Abstract
In the current era of noisy intermediate-scale quantum computers, noisy qubits can result in biased results for early quantum algorithm applications. This is a significant challenge for ...interpreting results from quantum computer simulations for quantum chemistry, nuclear physics, high energy physics (HEP), and other emerging scientific applications. An important class of qubit errors are readout errors. The most basic method to correct readout errors is matrix inversion, using a response matrix built from simple operations to probe the rate of transitions from known initial quantum states to readout outcomes. One challenge with inverting matrices with large off-diagonal components is that the results are sensitive to statistical fluctuations. This challenge is familiar to HEP, where prior-independent regularized matrix inversion techniques (“unfolding”) have been developed for years to correct for acceptance and detector effects, when performing differential cross section measurements. We study one such method, known as iterative Bayesian unfolding, as a potential tool for correcting readout errors from universal gate-based quantum computers. This method is shown to avoid pathologies from commonly used matrix inversion and least squares methods.
Background: A 3‐year course of specific immunotherapy (SIT) in children with hay fever to grass and/or birch pollen significantly reduced the risk of developing asthma. To investigate the long‐term ...preventive effect, we performed a follow up – 2 years after termination of immunotherapy.
Methods: A total of 183 children, aged 6–14 years with grass and/or birch pollen allergy could be investigated 2 years after discontinuation of SIT or no treatment. Conjunctival provocation tests (CPTs) and methacholine bronchial provocation tests were carried out during the season and winter after 5 years. The development of asthma was assessed by clinical evaluation.
Results: The significant improvement in hay fever and CPT results observed after 3 years of SIT persisted at the 5‐year follow‐up. No difference in bronchial responsiveness to methacholine was found after 5 years because of spontaneous improvement during the follow‐up period in the control patients. The immunotherapy‐treated children had significantly less asthma after 5 years as evaluated by clinical symptoms odds ratio 2.68 (1.3–5.7) in favor of SIT for prevention of development of asthma and significantly less patients reported an increase in asthma scores (P < 0.01).
Conclusion: Immunotherapy for 3 years with standardized allergen extracts of grass and/or birch shows long‐term clinical effect and preventive effect on development of asthma in children with seasonal rhinoconjunctivitis.
Cardiac stem cells (CSCs) delivered to the infarcted heart generate a large number of small fetal-neonatal cardiomyocytes that fail to acquire the differentiated phenotype. However, the interaction ...of CSCs with postmitotic myocytes results in the formation of cells with adult characteristics.
On the basis of results of in vitro and in vivo assays, we report that the commitment of human CSCs (hCSCs) to the myocyte lineage and the generation of mature working cardiomyocytes are influenced by microRNA-499 (miR-499), which is barely detectable in hCSCs but is highly expressed in postmitotic human cardiomyocytes. miR-499 traverses gap junction channels and translocates to structurally coupled hCSCs favoring their differentiation into functionally competent cells. Expression of miR-499 in hCSCs represses the miR-499 target genes Sox6 and Rod1, enhancing cardiomyogenesis in vitro and after infarction in vivo. Although cardiac repair was detected in all cell-treated infarcted hearts, the aggregate volume of the regenerated myocyte mass and myocyte cell volume were greater in animals injected with hCSCs overexpressing miR-499. Treatment with hCSCs resulted in an improvement in ventricular function, consisting of a better preservation of developed pressure and positive and negative dP/dt after infarction. An additional positive effect on cardiac performance occurred with miR-499, pointing to enhanced myocyte differentiation/hypertrophy as the mechanism by which miR-499 potentiated the restoration of myocardial mass and function in the infarcted heart.
The recognition that miR-499 promotes the differentiation of hCSCs into mechanically integrated cardiomyocytes has important clinical implications for the treatment of human heart failure.
The demand for alternative fueling methods to reduce the need for fossil fuels is not limited to the electrification of ground vehicles. More-electric and all-electric aircraft pose challenges, with ...extensive requirements in terms of power density, efficiency, safety, and environmental sustainability. This paper focuses on electrical machines and their components, especially for high-power applications like the main propulsion. The electrical machine is evaluated from different aspects, followed by a closer look at the components and materials to determine the suitability of the current standard materials and advanced technologies. Furthermore, the mechanical and thermal aspects are reviewed, including new and innovative concepts for the cooling of windings and for the use of additive manufacturing. Aircraft have special demands regarding weight and installation space. Following recent developments and looking ahead to the future, the need and the possibilities for light and efficient electrical machines are addressed. All of the approaches and developments presented lead to a better understanding of the challenges to be expected and highlight the upcoming opportunities in electrical machine design for the use of electric motors and generators in future aircraft. Several prototypes of electrical machines for smaller aircraft already exist, such as the electric drive of the Siemens powered Extra 330LE. The focus of this paper is to provide an overview of current technical possibilities and technical interrelations of high performance electric drives for aviation. A 1 MW drive is exemplified to present the possibilities for future drives for airplanes carrying a larger number of passengers. All presented techniques can also be applied to other drive power classes.
Cirrus clouds have a large influence on the Earth's climate and anthropogenic activities such as aviation can alter their properties. Besides the formation of contrails, indirect effects on naturally ...occurring cirrus like increased heterogeneous freezing due to exhaust soot particles are discussed in the literature. However, hardly any observational study exists. In this work we present cirrus optical properties measured by an airborne lidar over Europe during the Midlatitude Cirrus experiment (ML‐CIRRUS). One half of the cloud cases showed elevated depolarization ratios with a mode difference of 10 percentage points indicating differences in the clouds microphysical properties. Their origin can be traced back to highly frequented air traffic regions, and they show lower in‐cloud ice supersaturations. Our analysis reveals no influence of embedded contrails and temperature. These results could be explained by an indirect aerosol effect where heterogeneous freezing is caused by aviation exhaust particles.
Plain Language Summary
Civil airplanes emit exhaust gases and soot into the atmosphere, which can influence the Earth's climate in several ways. One possibility could be that emitted soot particles alter the formation of ice clouds, which has a potentially high climate impact. However, observational studies of this process are sparse. In this work we present ice clouds measured above Europe by an airborne remote sensing instrument. One group of clouds features elevated depolarization ratios implying altered crystal habits. It also shows lower ice supersaturation indicating a modified ice formation. We demonstrate that this is not caused by condensation trails present inside the clouds, by temperature, or by the dynamical state of the atmosphere. However, these clouds had formed in air that stemmed from highly frequented aviation corridors. Thus, our observations could be the first traces of this indirect process.
Key Points
We found two types of cirrus clouds in the Northern Hemisphere midlatitudes; one shows significantly higher depolarization ratios
These clouds also exhibit lower in‐cloud supersaturations and can be traced back to aviation corridors
Our analysis demonstrates that heterogeneous freezing on aviation exhaust particles could explain these results
Background
Prevention of new IgE sensitizations has been described during allergen‐specific immunotherapy. However, prospective data using a preventive approach in very young children who would ...benefit most are missing. We initiated a prospective pilot study investigating the safety, immunomodulatory, and sensitization‐preventive effect of sublingual immunotherapy (SLIT) in mono/oligoclonally sensitized, clinically asymptomatic children 2–5 yr of age.
Methods
In this double‐blinded, randomized, placebo‐controlled pilot study, 31 mono‐/oligosensitized children to house‐dust mite or grass pollen were included. SLIT with the respective source (n = 15) or placebo (n = 16) was applied. After dose‐up‐phase therapy was continued for 2 yr. Parents recorded clinical events, vaccinations, and drug intake in a diary. Skin prick testing and specific IgE and IgG measurements were recorded at baseline, 12 and 24 months. At the same time, allergen‐specific proliferation and IL10‐ and TGFβ‐dependent Treg function were measured.
Results
Preventive application of SLIT in young children was safe (no relevant side effects in 21,170 single applications). After 12 and 24 months of treatment, the rate of allergen‐specific sensitization (specific IgE and SPT reactivity) was comparable in the treatment and the placebo group. However, verum‐treated patients displayed a significant up‐regulation of allergen‐specific IgG (p < 0.05). Furthermore, IL10‐dependent inhibition (p < 0.05) was observed in vitro in the treatment group but not in the placebo group.
Conclusion
Preventive SLIT is safe in children 2–5 yr of age and induces regulatory mechanisms involving allergen‐specific IgG and IL10. Based on this pilot study, large‐scale trials will need to investigate the modulation of sensitization and clinically relevant allergy.
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