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This study evaluated the performance of 23 models participating in Phase 6 of the Coupled Model Intercomparison Project (CMIP6) in simulating snowfall variation across the Eurasian continent. The results show that the CMIP6 multi‐model ensemble (MME) can reasonably capture the climate means of snowfall indices for 1995–2014 period and has high pattern correlations with observations. However, most of CMIP6 models generally overestimate snowfall amounts, snowfall days and snowfall duration, and the overestimation is much clearer in spring. The performance of these models in simulating snowfall events with different grades (including light snowfall, moderate snowfall, heavy snowfall and snowstorm) becomes gradually poorer with higher snowfall levels. On the whole, the comprehensive model ranks implied that NorESM2‐MM, NorESM2‐LM and CESM2‐WACCM models showed the best performances. In addition, the CMIP6 MME outperforms individual models in terms of both spatial–temporal features and interannual variability; thus, the MME is used to project the snowfall change in the 21st century. Further evaluations show that by the end of this century, snowfall will decrease in most of Eurasia with an average value of 16.7% (31.3%) under the SSP2‐4.5 (SSP5‐8.5) scenarios, and snowfall days will decrease by 12.6 days (25.0 days); the snowfall duration will shorten further due to the first date of snowfall occurrence will postpone by 12.7 days (23.0 days) and the last date further advance by 15.0 days (26.7 days). Additionally, heavy snowfall, snowstorms and their number of days will increase over part of Northern Asia, the Tibetan Plateau and Central Asia, where the risk of snowfall extremes will increase. However, large inter‐model and scenario uncertainties also exist in the CMIP6 model projection of snowfall events, which requires further improvement. [ABSTRACT FROM AUTHOR]

The observed spatial–temporal variations in daily snowfall over the Eurasian continent from 1980 to 2019 are explored in this study. The results show that the snowfall amount and its number of days are mainly centred in the high latitudes and high terrain regions of the Eurasian continent (such as North Asia), while they are relatively small in Southern Europe, Central Asia and East Asia. During the past decades, a decreasing trend can be observed for snowfall amounts and the numbers of days over most regions of Eurasia, while increases are clear in terms of the mean intensity. In response to climate warming in recent decades, the first date of snowfall occurrence postponed and the ending date advanced across the Eurasian continent. Furthermore, the change characteristics of the different grades of snowfall are also investigated across this region, including light snowfall, moderate snowfall, heavy snowfall and snowstorm. The light snowfall and number of days show a decreasing tendency, which mainly results in a decrease in the total snowfall amount and number of days. However, the amounts of heavy snowfall and snowstorms and their numbers of days are significantly increased, implying that the Eurasian continent has experienced increased severe snowfall events during recent decades. [ABSTRACT FROM AUTHOR]

It has been widely reported that anthropogenic influences are detectable with high confidence in global warming. However, whether human activities have an impact on snowfall changes is still unclear. Here we based on phase 6 of the Coupled Model Intercomparison Project (CMIP6) multi-forcing dataset and the regularized optimal fingerprint method, the detection and attribution of various grades of snowfall (including annual snowfall (>0.1 mm/day), light snowfall (<2.5 mm/day), intense snowfall (>5 mm/day), and their corresponding days) changes in Eurasia (20 ° -90 °N , 10 °W -180 °E) were carried out. Results show that anthropogenic activity forcing (ANT) and greenhouse gas forcing (GHG) well reproduced the spatial-temporal characteristics of snowfall indices. The ANT influence is robustly detected in the decreased trend of snowfall days (snowday), light snowfall, and light snowfall days (light_day) at the 90% confidence interval, clearly separated from the natural forcing. Moreover, the GHG signals are detectable for decreases in the three snowfall indices, which only could be distinguished from the natural and aerosol forcings for snowday and light snowfall. Thus, anthropogenic activities may considerably account for the decreases in snowday, light snowfall, and light_day across Eurasia, wherein the changes in the first two indices dominated by GHG emissions. However, human influence detections fail for intense snowfall, and it is hard to detect on regional scales, except for North Asia. Finally, by the end of this century (2081–2100), the observation-constrained projections based on the detection and attribution analysis under two SSPs (new Shared Socioeconomic Pathway) scenarios exhibit that the scaled snowday, light snowfall, and light_day are expected to decrease by approximately 13.9 days (28.3 days), 24.8% (48.7%), and 4.3 days (8.8 days) under the SSP2–4.5 (SSP5–8.5) scenario with reference to the current climate (1995–2014). Our study highlights the need to improve climate model performance in simulating extreme snowfall to clear whether and to what extent human influence impacts it. In the past 35 years, the decrease in snowfall days (snowday), light snowfall, and light snowfall days (light_day) can be attributed to human influence. However, CMIP6 simulations may underestimate these observed changes. We utilize the observationally constrained techniques based on detection results to constrain the projections for snowfall changes. Our results show that by the end of the 21st century, the scaled snowday, light snowfall, and light_day are expected to decrease by approximately 13.9 days (28.3 days), 24.8% (48.7%), and 4.3 days (8.8 days) under the SSP2–4.5 (SSP5–8.5) scenario with reference to the current climate. [Display omitted] • In the past decades, the observed snowfall decreased while extreme snowfall increased across most of Eurasia. • The decrease in snowfall days and light snowfall could be attributed to anthropogenic influence dominated by GHG emissions. • CMIP6 models may underestimate the observed changes in snowfall. • The observation-constrained projections show a larger decrease for snowday and light snowfall than the raw CMIP6 outputs. [ABSTRACT FROM AUTHOR]

Data in the form of graphs are prevalent, ranging from biological and social networks to citation graphs and the Web. In particular, most real-world graphs are heterogeneous, containing objects of multiple types, which present new opportunities for many problems on graphs. Consider a typical proximity search problem on graphs, which boils down to measuring the proximity between two given nodes. Most earlier studies on homogeneous or bipartite graphs only measure a generic form of proximity, without accounting for different “semantic classes”—for instance, on a social network two users can be close for different reasons, such as being classmates or family members, which represent two distinct semantic classes. Learning these semantic classes are made possible on heterogeneous graphs through the concept of metagraphs. In this study, we identify metagraphs as a novel and effective means to characterize the common structures for a desired class of proximity. Subsequently, we propose a family of metagraph-based proximity, and employ a learning-to-rank technique that automatically learns the right parameters to suit the desired semantic class. In terms of efficiency, we develop a symmetry-based matching algorithm to speed up the computation of metagraph instances. Empirically, extensive experiments reveal that our metagraph-based proximity substantially outperforms the best competitor by more than 10 percent, and our matching algorithm can reduce matching time by more than half. As a further generalization, we aim to derive a general node and edge representation for heterogeneous graphs, in order to support arbitrary machine learning tasks beyond proximity search. In particular, we propose the finer-grained anchored metagraph, which is capable of discriminating the roles of nodes within the same metagraph. Finally, further experiments on the general representation show that we can outperform the state of the art significantly and consistently across various machine learning tasks. [ABSTRACT FROM AUTHOR]

The identification of network motifs has important applications in numerous domains, such as pattern detection in biological networks and graph analysis in digital circuits. However, mining network motifs is computationally challenging, as it requires enumerating subgraphs from a real-life graph, and computing the frequency of each subgraph in a large number of random graphs. In particular, existing solutions often require days to derive network motifs from biological networks with only a few thousand vertices. To address this problem, this paper presents a novel study on network motif discovery using Graphical Processing Units (GPUs). The basic idea is to employ GPUs to parallelize a large number of subgraph matching tasks in computing subgraph frequencies from random graphs, so as to reduce the overall computation time of network motif discovery. We explore the design space of GPU-based subgraph matching algorithms, with careful analysis of several crucial factors (such as branch divergences and memory coalescing) that affect the performance of GPU programs. Based on our analysis, we develop a GPU-based solution that (i) considerably differs from existing CPU-based methods in how it enumerates subgraphs, and (ii) exploits the strengths of GPUs in terms of parallelism while mitigating their limitations in terms of the computation power per GPU core. With extensive experiments on a variety of biological networks, we show that our solution is up to two orders of magnitude faster than the best CPU-based approach, and is around $20$ times more cost-effective than the latter, when taking into account the monetary costs of the CPU and GPUs used. [ABSTRACT FROM PUBLISHER]

Abstract: Oligonucleotides containing 7-bromo-7-deaza-2,8-diaza-2′-deoxyadenosine ( 3 ) and 5-amino-3-bromo-4-carbamoyl-1-(2′-deoxy-β-d-erythro-pentofuranosyl)pyrazole ( 4 ) were synthesized. Compound 3 was prepared from 7-bromo-8-aza-7-deaza-2′-deoxyadenosine ( 5 ) via the 1,N 6-etheno derivative 6 and was converted into the phosphoramidite 11 . The 7-bromo substituent of 3 increases oligonucleotide duplex stability compared to the non-halogenated nucleoside. Oligonucleotides incorporating 3 are transformed to those containing 4 during long time deprotection at elevated temperature (25% aq ammonia, 60°C, 30h). Compound 3 forms a strong base pair with dG. The base pair stability decreases in the order dG>dT>dA>dC. Similar recognition selectivity is observed for the pyrazole nucleoside 4 , however, due to decreased stacking and higher flexibility of the pyrazole moiety, duplexes are less stable than those containing 3 . [Copyright &y& Elsevier]

Alkyl azides and acyl azides were reduced to the corresponding amines and amides with zinc and ammonium chloride as reducing agent under mild conditions in good to excellent yield. [ABSTRACT FROM AUTHOR]

Background: The incidence of rabies exposure is high and increasing in China, leading to an urgent demand of rabies post-exposure prophylaxis (PEP) clinics for the injured. However, the spatial accessibility and inequality of rabies-exposed patients to rabies PEP clinics is less known in China. Methods: Based on rabies exposure data, PEP clinic data, and resident travel origin-destination (OD) matrix data in Guangzhou City, China, we first described the incidence of rabies exposure in Guangzhou from 2020 to 2022. Then, the Gaussian two-step floating catchment area method (2SFCA) was used to analyze the spatial accessibility of rabies-exposed patients to rabies PEP clinics in Guangzhou, and the Gini coefficient and Moran's I statistics were utilized to evaluate the inequality and clustering of accessibility scores. Results: From 2020 to 2022, a total of 524,160 cases of rabies exposure were reported in Guangzhou, and the incidence showed a significant increasing trend, with an average annual incidence of 932.0/100,000. Spatial accessibility analysis revealed that the overall spatial accessibility scores for three scenarios (threshold of driving duration [d0] = 30 min, 45 min, and 60 min) were 0.30 (95% CI: 0.07, 0.87), 0.28 (95% CI: 0.11, 0.53) and 0.28 (95% CI: 0.14, 0.44), respectively. Conghua, Huangpu, Zengcheng and Nansha districts had the higher accessibility scores, while Haizhu, Liwan, and Yuexiu districts exhibited lower spatial accessibility scores. The Gini coefficient and Moran's I statistics showed that there were certain inequality and clustering in the accessibility to rabies PEP clinics in Guangzhou. Conclusions: This study clarifies the heterogeneity of spatial accessibility to rabies PEP clinics, and provide valuable insights for resource allocation to achieve the WHO target of zero human dog-mediated rabies deaths by 2030. [ABSTRACT FROM AUTHOR]

A series of chiral oxazolines, which had been conveniently prepared from commercially available (1S,2S)-2-amino-1-phenylpropane-1,3-diol, was applied in the diethylzinc addition to diphenylphosphinoyl imines to give high yields of 68–84% and excellent e.e. values of 90–93%. [Copyright &y& Elsevier]

Personalized PageRank (PPR) is a classic measure of the relevance among different nodes in a graph, and has been applied in numerous systems, such as Twitter's Who-To-Follow and Pinterest's Related Pins. Existing work on PPR has mainly focused on three general types of queries, namely, single-pair PPR, single-source PPR, and all-pair PPR. However, we observe that there are applications that rely on a new query type (referred to as batch one-hop PPR), which takes as input a set $S$ S of source nodes and, for each node $s \in S$ s ∈ S and each of $s$ s 's neighbor $v$ v , asks for the PPR value of $v$ v with respect to $s$ s . None of the existing PPR algorithms is able to efficiently process batch one-hop queries, due to the inherent differences between batch one-hop PPR and the three general query types. To address the limitations of existing algorithms, this paper presents Baton, an algorithm for batch one-hop PPR that offers both strong theoretical guarantees and practical efficiency. Baton leverages the characteristics of one-hop PPR to avoid unnecessary computation, and it incorporates advanced mechanisms to improve the cost-effectiveness of PPR derivations. Extensive experiments on benchmark datasets show that Baton is up to three orders of magnitude faster than the state of the art, while offering the same accuracy. [ABSTRACT FROM AUTHOR]

Figure: The multimodel median changes of precipitation indices of R20mm (top), RX5day (middle), and CDD (bottom) by the end of 21st century (2081–2100) under the SSP245 (left) and SSP585 (right) scenarios with respect to the reference period 1986–2005. Here, shading is only shown for regions where at least 90% of the models agree on the direction of the change. CMIP6 models exhibit a general improvement in simulation of climate extremes and their trend patterns compared to observations. The model spread among CMIP6 models tends to be much smaller than that among their predecessors, particularly for regions in high northern latitudes. In response to further warming in the future, the TXx and TNn show a general increase in this century, but the increase in TNn is much greater than that in TXx. Additionally, precipitation indices of R20mm and RX5day are projected to significantly increase across lands, while increase in CDD is limited to the Southern Hemisphere (Figure). These changes are generally more pronounced in CMIP6 than CMIP5 simulations, but the model spreads are still comparable between CMIPs, which still needs further investigation. [ABSTRACT FROM AUTHOR]

• A terahertz compressed sensing imaging method based on line array detection is proposed. • In the experiment, the reconstruction of the letter sample is realized at a sampling rate of 16%. • The proposed technology is used to reconstruct the imaging images of the terahertz line scan system. In this paper, a terahertz compressed sensing imaging technique based on line array detection is proposed. The feasibility of the proposed terahertz compressed sensing imaging based on line array detection is verified by theoretical derivation, MATLAB and ZEMAX simulation as well as practical experiment. Firstly, we compare the traditional single-pixel compressed sensing imaging, block compressed sensing imaging and the proposed terahertz compressed sensing imaging based on line array detection by MATLAB simulation, and the results show that the proposed technique can achieve high-quality image reconstruction. Then, we import self-designed mask and lenses as well as other devices into ZEMAX to simulate the compressive sensing process of line array detection using non-sequential mode. According to the simulation results, a terahertz line array compressive sensing imaging system is built using a high-speed line-array detector. The experimental results show that the technique has higher imaging stability and the sampling process is highly generalizable to different objects. Compared with the traditional single-pixel random sampling compressed sensing method, this method greatly reduces the sampling rate and successfully reconstructs the original image at a sampling rate of 16%. We believe that the compressed sensing terahertz imaging technology based on line array detection proposed in this paper provides a new idea for terahertz multi-pixel compressed sensing imaging, which is expected to promote the development of terahertz high-resolution rapid imaging. In addition, this technology can be applied to both terahertz line and area scan imaging systems, which has great application potential in correcting image distortion caused by movement of imaging objects. [ABSTRACT FROM AUTHOR]

A metal catalyst free approach for regioselective ortho-chlorination of anilines has been developed using a secondary amine as the organocatalyst and sulfuryl chloride as the halogen source under mild conditions. A wide range of substrates were compatible with this catalytic system. In addition, this catalytic protocol has been applied to the efficient synthesis of bioactive compounds and modification of drug derivatives. Further studies indicated that the anionic trichloride species was responsible for the ortho-selectivity. [ABSTRACT FROM AUTHOR]

We report on an alternative modified TiO 2 -based photoanode for obtaining enhanced photovoltaic (PV) properties in DSSCs. Multiferroics BiFeO 3 was employed to construct BiFeO 3 +TiO 2 composite photoanode for DSSCs. Here, BiFeO 3 may also act as photoelectric conversion medium and increases photogenerated carrier transport channels, consequently, improves the PCE of DSSCs with BiFeO 3 +TiO 2 composite photoanodes. More importantly, magnetic-field enhanced PV properties in abovementioned DSSCs was firstly obtained. The investigated results offer both an alternative method to improve PV properties in DSSCs, and a referential train of thought to manipulate photoelectric properties of solar cells. [Display omitted] • Multiferroics BiFeO 3 , which presents magnetic, electric, and visible light catalytic properties, was firstly introduced to act as part of photoanode in the investigation of DSSCs. • Enhancement of photoelectric conversion efficiency in DSSC devices with BiFeO 3 + TiO 2 composite photoanodes has been obtained , indicating an alternative approach for enhancing photoelectric conversion efficiency of solar cells is achieved. Also, suggesting a promising potential in the application of photoelectric conversion. • External magnetic field enhancing photoelectric conversion performance was observed firstly in DSSC devices with BiFeO 3 + TiO 2 composite photoanodes. • Providing a universal way that can be available in photovoltaic cell field by non-contact external magnetic field modulation method. In dye-sensitized solar cells (DSSCs), the light absorbance of photoanode is the most important factor in power conversion efficiency (PCE). Here the authors report on an alternative modified TiO 2 -based photoanode for obtaining enhanced photovoltaic (PV) properties in DSSCs. Multiferroics BiFeO 3 , which possesses excellent magnetic, electric, and photocatalytic performances, was employed to construct BiFeO 3 + TiO 2 composite photoanode for DSSCs. In this type of DSSCs with BiFeO 3 + TiO 2 composite photoanodes, BiFeO 3 with suitable bandgap may also act as photoelectric conversion medium, which is generally acted by dye in DSSCs, and increases photogenerated carrier transport channels, which improves the PCE of DSSCs with BiFeO 3 + TiO 2 composite photoanodes. More importantly, magnetic-field enhanced PV properties in abovementioned DSSCs was firstly obtained, which may result from magnetic-field-suppression the recombination of charge carriers and magnetoresistance effect in BiFeO 3. The investigated results offer both an alternative method to improve PV properties in DSSCs, and a referential train of thought to manipulate photoelectric properties of solar cells. [ABSTRACT FROM AUTHOR]

In this paper, a spoof surface plasmon polaritons (SPPs)-based multi-frequency splitter in the terahertz (THz) band is realized by designing different grating heights. The structure is composed of an incident aperture waveguide and a composite gratings structure placed on both sides of the incident aperture waveguide. The composite grating structure has different grating heights, which is used to transmit and guide THz waves of different frequencies in different directions. Simulation results show that a mixed incident light consisting of three frequencies, of 0.5 THz, 0.7 THz and 1 THz, can be effectively separated by this splitter. Furthermore, the function of the spoof SPPs switch can be realized by increasing the number of incident aperture waveguides. The simple structure and small size, means that this multi-frequency splitter and switch can be conveniently integrated into THz sensing or THz communication systems. [ABSTRACT FROM AUTHOR]

Abstract: Two sets of novel chiral oxazoline ligands were designed and conveniently prepared from readily available l-aspartic acid and evaluated in enantioselective diethylzinc addition to N-diphenylphosphinoyl imines. In the presence of stoichiometric amounts of these ligands, high enantioselectivities (up to 95% ee) and yields (up to 85%) were achieved for several aromatic imines in toluene at room temperature. Furthermore, the effect of the structure of the ligand on the reaction was studied. [Copyright &y& Elsevier]

Abstract: Enantioselective hydrosilylation of N-aryl and N-benzyl ketimines with trichlorosilane catalyzed by readily accessible chiral N-picolinoylaminoalcohols proceeded smoothly furnishing chiral secondary amines in good yields (up to 93%) and moderate to excellent enantioselectivities (up to 95% ee). [Copyright &y& Elsevier]

• Aspheric lens for large depth-of-field terahertz imaging at long distances. • Depth-of-field extension is achieved by incident light with a wide field-of-view. • Farther from the element than the Bessel beam depth-of-field start point. • Fast imaging of large targets can be achieved with multipixel terahertz detectors. Terahertz (THz) imaging can serve as a versatile instrument to disclose contents of various packages or items hidden under clothing. When imaging a large target with a certain thickness at a long distance, the requirements for the imaging speed and imaging quality of the system are particularly worthy of attention. To tackle these problems and extend an assortment of application, this paper proposes a wide field-of-view (FOV) aspheric lens suitable for rapid imaging systems for extending the depth-of-field (DOF) of THz imaging at long distances. The designed aspherical lens with a diameter of 264 mm – made of high-density polyethylene (HDPE) and manufactured by machining – allows extending the DOF up to 85 mm by separately focusing incident light with different FOV angles, which not only allows fast THz imaging combined with linear array detector but also refuses the use of complicated imaging optical paths. A reflective one-dimensional (1D) scanning imaging system with a 0.1 THz source reveals that the lens can simultaneously achieve wavelength-level resolution and a DOF range of 85 mm for objects at a distance greater than 415 mm from the lens surface in a wide-field illumination system, in which the contrast of the obtained results can reach more than 15%. The observed results justify the application value of the lens in long-distance, wide-field THz imaging systems. [ABSTRACT FROM AUTHOR]

• A modified isotope-based method was developed to estimate the evapotranspiration partitioning, and it can be applied on various time scales. • The modified method and the traditional method are equivalent at a 15-minute time scale. • The modified method is capable of partitioning evapotranspiration at high-frequency and distributed the high sensitivity parameter δ ET into other three less sensitive parameters. • The high-frequency method is advantageous in avoiding the extrapolation of the keeling plot regression line, and enabling the calculation of confidence interval of evapotranspiration partition. • The high-frequency method might be useful when investigating evapotranspiration partitioning under short-term extreme weather events and flush agricultural irrigation. To better understand water and energy cycles, numerous efforts to partition evapotranspiration (ET) into evaporation (E) and transpiration (T) have been made over the recent half century. One of the analytical methods is the isotopic approach. The isotopic composition of ET (δ ET) is a crucial parameter in the traditional isotope-based ET partitioning model, which however, has considerable uncertainty and high sensitivity. Here we proposed a modified T fraction in total ET (F T) calculation using Keeling plot slope (k), the atmospheric vapor concentration (C v), and the isotopic composition of atmospheric vapor (δ v), to avoid the direct use of δ ET. Following the traditional method, we used the Craig-Gordon model for the isotopic composition of evaporation (δ E) and chamber method for the isotopic composition of transpiration (δ T) in our modified method. The modified F T calculation method (F T (m)) can be applied at a 15-min time scale using the average values (F Ti (mp)) and at a 1 Hz time scale for high-frequency method (F Ti). The modified method was verified by both theoretical derivations and field observations. F Ti (mp) was equivalent to those using the traditional isotopic method at a 15-min time scale. However, F Ti eliminated the highly sensitive parameter δ ET , and redistributed the sensitivity of δ ET into three less sensitive parameters. Additionally, F Ti has two main advantages. First, the high-frequency method avoids the extrapolation of the Keeling plot regression line intercept. Second, the high-frequency method can produce a 95% confidence interval of F T in a measurement cycle (e.g., 15 min). The calculated confidence interval was different from that of traditional uncertainty analysis. The high-frequency method might be useful when investigating evapotranspiration partitioning under short-term extreme weather events and flush agricultural irrigation. [ABSTRACT FROM AUTHOR]

Abstract: Ethyl (R)-2-hydroxy-4-phenylbutyrate ((R)-HPBE), a key intermediate in the production of angiotensin-converting enzyme (ACE) inhibitors, was prepared by the microbial reduction of ethyl 2-oxo-4-phenylbutyrate (OPBE). Among 63 microorganisms tested, Candida krusei SW2026, for the first time, was proven to be a highly effective biocatalyst in this reduction process, leading to the (R)-enantiomer in 99.7% ee and 95.1% yield at 2.5g/L of OPBE (under optimal conditions of 30°C, pH 6.6, and in the presence of 5% glucose as co-substrate). In order to achieve higher product concentration with desired enantiopurity and yield for application in large-scale production, strategies such as substrate fed-batch and aqueous/organic biphasic system were successfully conducted in the biotransformation reaction. At 20g/L of OPBE, the enantiomeric excess (ee), yield, and product concentration were enhanced to 97.4%, 82.0%, and 16.6g/L, respectively, in water/dibutyl phthalate biphasic system, compared with 87.5%, 45.8%, and 9.2g/L in aqueous medium. This study provides an attractive process of (R)-HPBE production for potential green chemistry applications. [Copyright &y& Elsevier]