Toward Earth system modeling with resolved clouds and ocean submesoscales on heterogeneous many-core HPCs.

With the aid of the newly developed 'Sunway' heterogeneous-architecture supercomputer, which has world-leading HPC (high-performance computer) capability, a series of high-resolution coupled Earth system models (SW-HRESMs) with up to 5 km of atmosphere and 3 km of ocean have been developed. These models can meet the needs of multiscale interaction studies with different computational costs. Here we describe the progress of SW-HRESMs development, with an overview of the major advancements made by the international Earth science community in HR-ESMs. We also show the preliminary results of SW-HRESMs with regard to capturing major weather-climate extremes in the atmosphere and ocean, stressing the importance of permitted clouds and ocean submesoscale eddies in modeling tropical cyclones and eddy-mean flow interactions, and paving the way for further model development to resolve finer scales with even higher resolution and more realistic physics. Finally, in addition to increasing model resolution, the development procedure for a non-hydrostatic cloud and ocean submesoscale resolved ESM is discussed, laying out the major scientific directions of such a huge modeling advancement.

Early visual quality outcomes after small-incision lenticule extraction surgery for correcting high myopic astigmatism.

BACKGROUND: To evaluate early optical quality outcomes after small-incision lenticule extraction (SMILE) surgery for correcting high myopic astigmatism. METHODS: This retrospective study enrolled 55 eyes from 37 patients who had preoperative myopic astigmatism of ≥2.00 diopters (D) who had been treated with SMILE surgery. Preoperatively, the mean cylinder was - 2.41 ± 0.54 D (range, - 2.00 D to - 4.50 D). The preoperative and postoperative visual outcomes, refraction, and higher-order aberration (HOA) at 1 and 3 months were compared. Refractive astigmatism changes were analyzed by the Alpins vector method. RESULTS: Three months after SMILE surgery, the average cylinder was - 0.14 ± 0.31 D, and the average astigmatism vector was - 0.09 D × 6.34°. The angle of error (AofE) was limited to within ±10°, and the magnitude of error was limited to within ±1.0 D in all patients. The correction index (CI) was 0.98 ± 0.07, the index of success (IOS) was 0.08 ± 0.13, and the flattening index (FI) was 0.97 ± 0.07. Significant positive correlations were found between IOS and |AofE| (P = 0.000); negative correlations were found between FI and |AofE| (P = 0.000). The postoperative total HOA, spherical aberration, vertical coma aberration, and trefoil 30° were increased significantly compared with preoperative measurements, and the increase in HOA was closely related to preoperative astigmatism (P < 0.05). CONCLUSIONS: SMILE has preferable outcomes for correcting high myopic astigmatism. Axis rotation during the surgery might influence the undercorrection of astigmatism. The increase of HOA after surgery is related to preoperative astigmatism.

A New Class of Scandium Carbide Nanosheet.

A new class of two-dimensional scandium carbide nanosheet has been identified by using first-principles density functional theory. It has a primitive cell of Sc3C10, in which there are two pentagonal carbon rings surrounded by one scandium octagon. Being as the precussor of Volleyballene Sc20C60 and ScC nanotubes, the Sc3C10 nanosheet is exceptionally stable. By rolling up this Sc3C10 sheet, a series of stable ScC nanotubes have been obtained. All the nanotubes studied have been found to be metallic. Furthermore, the hydrogen storage capacity of the ScC nanotubes has been explored. The calculated results show that one unit of the (0,3) ScC nanotube can adsorb a maximum of 51 hydrogen molecules, reaching up to a 6.25 wt% hydrogen gravimetric density with an average binding energy of 0.23 eV/H2.

A hybrid human and organisational analysis method for railway accidents based on STAMP-HFACS and human information processing.

Safety is a constant priority for the railway industry and there are numerous hazards in and around the rail system which may result in damage to train and environment, human injury and fatalities. Low levels of human and organisational performance have been shown to be a prime cause of railway accidents and a number of accident models and methods have been developed in order to probe deeper into the role played by organisational factors in accident causation. The Systems-Theoretical Accident Modelling and Processes (STAMP) method for example, represents a promising systematic and systemic way of examining sociotechnical systems such as the railway. Another method, the Human Factors Analysis and Classification System (HFACS), based upon Reason's model of human error in an organisational context, has also proved popular as a human factors accident analysis framework. However, human factors elements are still somewhat limited and under-specified and these managerial and social issues within an organisation are simply regarded as sources of failure in the control constraints of STAMP. HFACS likewise, categorises accident data rather than analysing it in more depth. In this context, a hybrid human and organisational analysis method based on HFACS-STAMP (HFACS-STAMP method for railway accidents, HS-RAs) is proposed to identify and analyse human and organisational factors involved in railway accidents. Using the categories of human errors derived from HFACS and the structured systematic analysis process of STAMP, the HS-RAs method provides a mechanism by which active failures can promulgate across organisations and give a systemic analysis of human error in accidents. Combined with human information processing, the HS-RAs method gives a detailed causal analysis of human errors from receiving information to implement control actions. At last, the HS-RAs method is demonstrated using a case study of the 2011 Yong-Wen railway collision. A number of prominent accident causes of human factors are revealed and necessary countermeasures are proposed to avoid the recurrence of similar accidents. The HFACS-STAMP hybrid method has several advantages and can contribute to railway safety by providing a detailed analysis of the role of human error in railway accidents.

[Analysis of the dynamic changes of cornea after myopic excimer laser in situ keratomileusis using an Orbscan II topography system].

OBJECTIVE: To study the changes and influence factors of an Orbscan II topography system in myopia after excimer laser in situ keratomileusis (LASIK). METHODS: Two hundred and sixteen myopia patients (230 eyes) were treated by LASIK, their corneal thickness and curve of corneal posterior surface was measured with an Orbscan II topography system before and after surgery. The results of measurement in different time points were compared. RESULTS: The thinnest point of cornea, the mean keratometry of the posterior best fit surface (BFS) and the distance from the apex to the BFS were significant difference before and after operation (P < 0.05). There were significant difference among those groups in different degree of myopia in the same time point (P < 0.05) after surgery, but there were no significant difference in the same group in difference time (P > 0.05). A significant difference in the area of the thinnest cornea before surgery and after surgery was detected among those groups (P < 0.01). The regression equation for preoperative Diff value was established as Y = 0.0941 - 0.000,53X(1) - 0.000,471X(2) - 0.0063X(3) + 0.001,22X(4) (P < 0.01), X(1) = corneal thickness of the thinnest point (microm), X(2) = central corneal thickness (microm), X(3) = corneal diameter (mm), X(4) = length of ocular axis (mm). The regression equation for postoperative decrease Diff value between the third month and the first month was produced as Y = - 0.027 - 0.000,78X(1) + 0.002,01X(2) - 0.0055X(3) (P < 0.01). X(1) = decrease in corneal thickness of the thinnest point (microm), X(2) = intraocular pressure pre-surgery (mmHg), X(3) = decrease in curvature of posterior corneal surface (D). CONCLUSIONS: The application of Orbscan II has an important clinical significance before and after LASIK. The Diff value measured before LASIK for myopia is influenced by the corneal thickness, corneal diameter and ocular axis. The postoperative decrease in Diff value between the third and first month is influenced by the postoperative decrease of corneal thinnest point and curvature of posterior corneal surface, and preoperative intraocular pressure.