Twelve-qubit quantum computing for chemistry Accurate electronic structure calculations are considered one of the most anticipated applications of quantum computing that will revolutionize ...theoretical chemistry and other related fields. Using the Google Sycamore quantum processor, Google AI Quantum and collaborators performed a variational quantum eigensolver (VQE) simulation of two intermediate-scale chemistry problems: the binding energy of hydrogen chains (as large as H 12 ) and the isomerization mechanism of diazene (see the Perspective by Yuan). The simulations were performed on up to 12 qubits, involving up to 72 two-qubit gates, and show that it is possible to achieve chemical accuracy when VQE is combined with error mitigation strategies. The key building blocks of the proposed VQE algorithm are potentially scalable to larger systems that cannot be simulated classically. Science , this issue p. 1084 ; see also p. 1054
Accurate quantum simulations of chemistry are performed using up to 12 superconducting qubits and 72 two-qubit gates.
The simulation of fermionic systems is among the most anticipated applications of quantum computing. We performed several quantum simulations of chemistry with up to one dozen qubits, including modeling the isomerization mechanism of diazene. We also demonstrated error-mitigation strategies based on N -representability that dramatically improve the effective fidelity of our experiments. Our parameterized ansatz circuits realized the Givens rotation approach to noninteracting fermion evolution, which we variationally optimized to prepare the Hartree-Fock wave function. This ubiquitous algorithmic primitive is classically tractable to simulate yet still generates highly entangled states over the computational basis, which allowed us to assess the performance of our hardware and establish a foundation for scaling up correlated quantum chemistry simulations.
Retinitis pigmentosa (RP), the most common form of inherited retinal degeneration, is clinically and genetically heterogeneous and can appear as syndromic or non-syndromic. Mucopolysaccharidosis type ...IIIC (MPS IIIC) is a lethal disorder, caused by mutations in the heparan-alpha-glucosaminide N-acetyltransferase (HGSNAT) gene and characterized by progressive neurological deterioration, with retinal degeneration as a prominent feature. We identified HGSNAT mutations in six patients with non-syndromic RP. Whole exome sequencing (WES) in an Ashkenazi Jewish Israeli RP patient revealed a novel homozygous HGSNAT variant, c.370A>T, which leads to partial skipping of exon 3. Screening of 66 Ashkenazi RP index cases revealed an additional family with two siblings homozygous for c.370A>T. WES in three Dutch siblings with RP revealed a complex HGSNAT variant, c.398G>C; 1843G>A on one allele, and c.1843G>A on the other allele. HGSNAT activity levels in blood leukocytes of patients were reduced compared with healthy controls, but usually higher than those in MPS IIIC patients. All patients were diagnosed with non-syndromic RP and did not exhibit neurological deterioration, or any phenotypic features consistent with MPS IIIC. Furthermore, four of the patients were over 60 years old, exceeding by far the life expectancy of MPS IIIC patients. HGSNAT is highly expressed in the mouse retina, and we hypothesize that the retina requires higher HGSNAT activity to maintain proper function, compared with other tissues associated with MPS IIIC, such as the brain. This report broadens the spectrum of phenotypes associated with HGSNAT mutations and highlights the critical function of HGSNAT in the human retina.
In this paper, an effective procedure for broken rotor bar (BRB) fault detection in a three-phase squirrel-cage induction machine (SCIM) is proposed. This approach relies on a motor current signature ...analysis (MCSA) by observing the specific fault-related current component generated by applying the DC injection braking method. Unlike the traditional MCSA, which is commonly focused on the detection of BRB sidebands around the fundamental current component, the proposed methodology introduces a new BRB feature in the current spectrum which makes it much easier for identification. The distinctive time-frequency evolution pattern of this feature provides the reliable identification of BRBs, even under no-load operating conditions, thus overcoming the major drawback of traditional MCSA-based methods. Fault severity classification is easily performed through the magnitude inspection of the BRB fault-related current component. In addition, the proposed approach does not require high-complexity signal processing algorithms to achieve reliable results. The proposed concept is presented theoretically, assisted by a magnetically coupled multiple circuit model of the SCIM, both with healthy and faulty rotor bars. Finally, the experimental tests validate the proposed methodology and demonstrate its effectiveness and usefulness.
The coronavirus disease 2019 (COVID-19) pandemic has disproportionately affected patients with kidney disease, causing significant challenges in disease management, kidney research and trainee ...education. For patients, increased infection risk and disease severity, often complicated by acute kidney injury, have contributed to high mortality. Clinicians were faced with high clinical demands, resource shortages and novel ethical dilemmas in providing patient care. In this review, we address the impact of COVID-19 on the entire spectrum of kidney care, including acute kidney injury, chronic kidney disease, dialysis and transplantation, trainee education, disparities in health care, changes in health care policies, moral distress and the patient perspective. Based on current evidence, we provide a framework for the management and support of patients with kidney disease, infection mitigation strategies, resource allocation and support systems for the nephrology workforce.
Using Moderate Resolution Imaging Spectroradiometer (MODIS) (Aqua and Terra satellites) and in situ observations, a comparative analysis of two large-scale smoke events caused by the summer wildfires ...in European Russia (ER) in 2010 and Western Siberia (WS) in 2012 was carried out. In the 5-day periods of the extreme smoke pollution (5-9 August 2010 in ER and 27-31 July 2012 in WS), the number of active fires in the equal territories, confined by the coordinates 47°-65° N, 25°-55° E and 51°-70° N, 71°-104° E, was found to be 4754 for ER and 3823 for WS. With this, the regional mean aerosol optical depths (AODs) were found to be (1.02 ± 0.02) and (1.00 ± 0.04), not much differing for both the events. The regional mean aerosol radiative forcing effects at the top (R
1
) and the bottom (R
2
) of the atmosphere over ER/WS according to MODIS observations were estimated to be (−61 ± 1) and (−54 ± 2) W m
−2
, and (−107 ± 2) and (−96 ± 3) W m
−2
, respectively. At the same time, the local values of AOD and the local absolute values of R
1
and R
2
over WS were considerably higher than those over ER. MODIS AOD (L3) data during the wildfires of 2010 were validated by AOD data obtained by the sun-sky photometer CIMEL, operating at the AERONET station Zvenigorod. The rates of radiative heating of the smoky atmosphere over ER and WS were also estimated and compared with the existed temperature anomalies, obtained using National Centers for Environmental Prediction National Center for Atmospheric Research reanalysis data. Optical and microphysical properties of smoke aerosols during the wildfires in ER and WS also revealed some similar characteristics. The aerosols were mostly found in the submicron-size fraction and characterized by very high single-scattering albedos (0.95-0.98). In the dense smoke conditions, the degree of linear polarization at the scattering angle 90° during both the events decreased to negative values ranging between −0.1 and −0.15. The optical properties of smoke aerosols were mainly conditioned by unusually narrow particle size distribution.
In a situation of rapidly changing environmental conditions and the growth of stress of different strengths and orientations, people are more likely to experience anxiety. The results of ...epidemiological studies show that up to 33.7% of the population suffers from lifelong anxiety disorders. According to large population-based surveys, comorbidity among people with this pathology is high: three out of four people with anxiety disorder experience at least one other mental disorder during their lifetime. The pathogenetic mechanisms of anxiety and insomnia are closely related, mutually aggravating each other’s influence. The difficulty of sleep generation and regulation makes this process very vulnerable to sleep and circadian rhythms disturbances, which include problems with the quality, time and quantity of sleep. Some researchers suggest that anxiety acts as an endogenous factor that affects the manifestations of the sleep-wake cycle, and the irregularity of this cycle contributes to anxiety. Recent studies display that chronotype may also be an important occurrence marker of chronic primary insomnia and a risk factor for anxiety disorders.The COVID-19 pandemic has become a major challenge for the mental health of people around the world. Numerous scientific publications have covered the prevalence of mental and behavioural disorders, including anxiety and dyssomnia, both in the context of psychosocial stress caused by the COVID-19 pandemic and in patients with long-term consequences after coronavirus disease. The term “Long COVID” covers a number of features that indicate damage to many organs, and lasts for weeks and months after the onset of the disease. An analysis of the literature shows that although physical symptoms are given the most attention, the impact of COVID-19 on mental health is no less important. At present, the long-term COVID-19 syndrome has not been definitively identified, but the leading signs of mental disorders after coronavirus disease, including sleep problems, anxiety, depression, fatigue, and cognitive difficulties, have been described.
The preparation of multicomponent coatings based on silicon and yttrium on the niobium substrate was investigated. Y-Si/NbSi2 coatings on the Nb substrate by currentless deposition in molten salts ...were produced. The preparation of NbSi2 layers is carried out in NaF-NaCl-Na2SiF6 melts with the addition of Si powder. The preparation of Y-Si layers is carried out in NaCl-KCl-YF3 melts containing Y powder. Coating samples are studied using SEM. It is established that sequentially synthesized coatings are characterized by a two-layer structure. Using the EDS method, the chemical composition of the obtained layers is established: Y - 26.68; Nb - 62.55; Si - 10.76 wt. %. The oxidation test of the obtained coatings Y-Si/NbSi2 on Nb samples is performed. It is found that testing at 1200 ˚C for 2 hours leads to a mass loss of 62 mg/cm2·h.
This article deals with problem of renewable enery resource studying during laboratory works of Power Engeneering students (bachelors and masters levels). Hardware and sofware RTDS complex is ...considered as a base of lab works. Solar panel (PV module) is considered as an example of renewable source. Plan of lab work, which is connectd with practical using, is offered.
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