Belief-propagation (BP) decoders play a vital role in modern coding theory, but they are not suitable to decode quantum error-correcting codes because of a unique quantum feature called error ...degeneracy. Inspired by an exact mapping between BP and deep neural networks, we train neural BP decoders for quantum low-density parity-check codes with a loss function tailored to error degeneracy. Training substantially improves the performance of BP decoders for all families of codes we tested and may solve the degeneracy problem which plagues the decoding of quantum low-density parity-check codes.
This study extends Boudon's positional theory to understand how students from different social origins make choices about university and how they interpret risks during the choice-making process in ...contemporary China. I draw upon empirical evidence from 71 in-depth semi-structured interviews with undergraduates from different social backgrounds and from different types of universities. The interview data confirm the relevance of Boudon's thesis in the Chinese context; that is, individuals' family characteristics manifest in the process of choices and strategies. Furthermore, this study provides new evidence on a pattern of class-bound conformity, which sometimes contradicts the rational course of action from students' narratives on socioeconomic and cultural identity as well as opportunity risks associated with the quota system. When hope and chance clash, students from working-class or agricultural families reduce to internalize their socioeconomic or geographical disadvantages, come to terms with a lack of equal opportunities in a seemingly meritocratic system. (HRK / Abstract übernommen).
With the increasing value of data and the growing power in the field of digital economy, China has taken the governance of cross-border data flow(CBDF) as an important national strategy. At the ...domestic policy level, China has piloted Beijing, Shanghai, Hainan and Xiongan New Area to create international data centers with the intention to control inbound and outbound data resources. At the domestic legislative level, China insists that the outbound data transfers be conducted in a secure environment. At the international cooperation level, on the basis of the Global Data Security Initiative, China builds the consensus of countries and promotes cooperation among countries along the Belt and Road routes on CBDF through the Digital Silk Road. Simultaneously, China will engage proactively in the newly international economic and trade agreements, with RCEP standing as a prime example. China’s discourse and model on CBDF governance have been continuously enhanced.
Atropisomerism is a stereochemical behavior portrayed by three-dimensional molecules that bear rotationally restricted σ bond. Akin to the well-represented point-chiral molecules, atropisomerically ...chiral compounds are finding increasing utilities in many disciplines where molecular asymmetry is influential. This provides steady demand on atroposelective synthesis, where numerous synthetic pursuits have been rewarded with conceptually novel and streamlined methods while expanding the structural diversity of atropisomers. This review summarizes key achievements in stereoselective preparation of biaryl, heterobiaryl, and nonbiaryl atropisomers documented between 2015 and 2020. Emphasis is placed on the synthetic strategies for each structural class, while examples are cited to illustrate the potential applications of the accessed atropochiral targets.
Residential green and blue spaces may be therapeutic for the mental health. However, solid evidence on the linkage between exposure to green and blue spaces and mental health among the elderly in ...non-Western countries is scarce and limited to exposure metrics based on remote sensing images (i.e., land cover and vegetation indices). Such overhead-view measures may fail to capture how people perceive the environment on the site.
This study aimed to compare streetscape metrics derived from street view images with satellite-derived ones for the assessment of green and blue space; and to examine associations between exposure to green and blue spaces as well as geriatric depression in Beijing, China.
Questionnaire data on 1190 participants aged 60 or above were analyzed cross-sectionally. Depressive symptoms were assessed through the shortened Geriatric Depression Scale (GDS-15). Streetscape green and blue spaces were extracted from Tencent Street View data by a fully convolutional neural network. Indicators derived from street view images were compared with a satellite-based normalized difference vegetation index (NDVI), a normalized difference water index (NDWI), and those derived from GlobeLand30 land cover data on a neighborhood level. Multilevel regressions with neighborhood-level random effects were fitted to assess correlations between GDS-15 scores and these green and blue spaces exposure metrics.
The average cumulative GDS-15 score was 3.4 (i.e., no depressive symptoms). Metrics of green and blue space derived from street view images were not correlated with satellite-based ones. While NDVI was highly correlated with GlobeLand30 green space, NDWI was moderately correlated with GlobeLand30 blue space. Multilevel regressions showed that both street view green and blue spaces were inversely associated with GDS-15 scores and achieved the highest model goodness-of-fit. No significant associations were found with NDVI, NDWI, and GlobeLand30 green and blue space. Our results passed robustness tests.
Our findings provide support that street view green and blue spaces are protective against depression for the elderly in China, yet longitudinal confirmation to infer causality is necessary. Street view and satellite-derived green and blue space measures represent different aspects of natural environments. Both street view data and deep learning are valuable tools for automated environmental exposure assessments for health-related studies.
•Deep learning and street view images were used to assess streetscape green and blue space.•Street view green and blue spaces were uncorrelated with satellite-derived metrics (i.e., NDVI, NDWI, and GlobeLand30).•The mental health of elderly people seemed enhanced by exposure to street view green and blue spaces.•No evidence of depression-green and blue space associations when remote sensing-based metrics were used.•People-centric exposure assessments using street view data provide great potential for environmental health studies.
The safety and efficacy of anti-diabetic drugs are critical for maximizing the beneficial impacts of well-controlled blood glucose on the prognosis of individuals with COVID-19 and pre-existing type ...2 diabetes (T2D). Metformin is the most commonly prescribed first-line medication for T2D, but its impact on the outcomes of individuals with COVID-19 and T2D remains to be clarified. Our current retrospective study in a cohort of 1,213 hospitalized individuals with COVID-19 and pre-existing T2D indicated that metformin use was significantly associated with a higher incidence of acidosis, particularly in cases with severe COVID-19, but not with 28-day COVID-19-related mortality. Furthermore, metformin use was significantly associated with reduced heart failure and inflammation. Our findings provide clinical evidence in support of continuing metformin treatment in individuals with COVID-19 and pre-existing T2D, but acidosis and kidney function should be carefully monitored in individuals with severe COVID-19.
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•A retrospective study of 1,213 patients on metformin with COVID-19 was performed•Metformin was associated with increased incidence of acidosis in such patients•Metformin was not associated with increased 28-day all-cause mortality in the patients•Metformin was significantly associated with reduced heart failure and inflammation
In a cohort of 1,213 hospitalized patients with COVID-19 and pre-existing type 2 diabetes, Cheng et al. show that metformin use is significantly associated with higher incidence of acidosis, particularly in cases with severe COVID-19, but not with 28-day all-cause mortality. They also found that metformin use is significantly associated with reduced heart failure and inflammation.
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•Accurate assessment of China’s ecological environment changes in the past 20 years is important.•We used time-series NDVI data (1998–2018) to evaluate China’s ecological environment ...change.•In one-third of China the ecological environment has improved, and in 10%, the ecological environment has deteriorated.•The Yellow River Basin is an area where the ecological environment has significantly improved.•The main reason for the deterioration in the ecological environment of the eastern coastal areas is urban expansion.
The ecological environment is the foundation of human survival and development. China’s ecological environment has undergone a historic transition from partial improvement to overall improvement. In this paper, long time series NDVI data (1998–2018) are used to evaluate the ecological environment change and spatiotemporal change that has taken place in China over the last 20 years, at different scales (regional, provincial, county, and grid scales). Combined with typical areas, the causes of ecological environment change are revealed. The results show that in about one-third of China, the ecological environment improved, and in 10%, the ecological environment deteriorated. Ningxia, Shaanxi, Shanxi, Guizhou, and Guangxi are the provinces in which the improvement of the ecological environment is most pronounced. However, the ecological environments with vegetation as the core in Shanghai and Jiangsu Province have deteriorated significantly. The areas with the fastest improvement in their ecological environment are those with precipitation of 200–600 mm. The Yellow River Basin is an area where the ecological environment has significantly improved. Forestry projects and the development of oasis agriculture effectively promote the improvement of the ecological environment. In the past 20 years, the main reason for the degradation of the ecological environment in eastern coastal areas is urban expansion. China should continue to strengthen its overall layout of forestry projects and improve its ecological environment. When planning its ecological construction, China should fully consider the associated physical and geographical conditions, and adjust measures to local conditions accordingly. China should coordinate the relationship between development and protection and avoid the “pie spread” expansion witnessed in eastern coastal areas.
A family of fully sandwiched arachno‐lanthanacarborane complexes formulated as {η6‐μ‐1,2‐o‐C6H4(CH2)2‐1,2‐C2B10H102Ln}{Li5(THF)10} (Ln=Tb, Dy, Ho, Er, Y) is successfully synthesized, where the ...“carbons‐adjacent” carboranyl ligand (arachno‐R2‐C2B10H104−) bears four negative charges and coordinates to the central lanthanide ions using the hexagonal η6C2B4 face. Thus, the central lanthanide cations are pseudo‐twelve‐coordinate and have an approximate pseudo‐D6h symmetry or hexagonal‐prismatic geometry. As the crystal field effect imparted by this geometry is still unknown, we thoroughly investigated the magnetic properties of this series of complexes and found that the crystal field imposed by this ligand causes a relation of Tb>Dy>Ho>Er for the energy gaps between the ground and the first excited states, which is of striking resemblance to the ferrocenophane and phthalocyanine ligands although the latter two ligands give disparate local coordination geometries. Moreover, the effective energy barrier to magnetization reversal of 445(10) K, the observable hysteresis loop up to 4 K and the relaxation time of the yttrium‐diluted sample reaching 193(17) seconds at 2 K under an optimized field for the Tb analogue of this family of arachno‐lanthanacarborane complexes, render a new benchmark for Tb3+‐based single‐molecule magnets.
A family of fully sandwiched lanthanide single‐molecule magnets derived from the tetraanionic arachno‐carboranyl ligand possess a pseudo hexagonal‐prismatic local coordination geometry which significantly enhances the magnetic axiality of the terbium(III) analogue.
Radical‐involved enantioselective oxidative C−H bond functionalization by a hydrogen‐atom transfer (HAT) process has emerged as a promising method for accessing functionally diverse enantioenriched ...products, while asymmetric C(sp3)−H bond amination remains a formidable challenge. To address this problem, described herein is a dual CuI/chiral phosphoric acid (CPA) catalytic system for radical‐involved enantioselective intramolecular C(sp3)−H amination of not only allylic positions but also benzylic positions with broad substrate scope. The use of 4‐methoxy‐NHPI (NHPI=N‐hydroxyphthalimide) as a stable and chemoselective HAT mediator precursor is crucial for the fulfillment of this transformation. Preliminary mechanistic studies indicate that a crucial allylic or benzylic radical intermediate resulting from a HAT process is involved.
Radical control: The first radical‐involved intramolecular enantioselective oxidative C−H amination of not only allylic substrates, but also benzylic substrates, by a hydrogen atom transfer process with a CuI/chiral phosphoric acid catalytic system is reported. Critical to the success is the use of 4‐methoxy‐PINO as a stable and chemoselective hydrogen or.
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