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Background: The reviews on the risk factors with ARDS and the worse outcomes concluded lacking robust data of risk factors to prevent COVID-19 and identified an urgent need for large sample and high-quality research in this area, as well as the features of the ARDS.Methods: This retrospective cohort study included 333 COVID-19 inpatients at two hospitals in Hubei of China in 2020. The COVID-19-related ARDS was diagnosed according to the Berlin criteria. The outcomes were ARDS development and the intubation or in-hospital death. The cox proportional hazard ratio (HR) models were employed to determine the significant risk factors. Results: The median number of days from symptom onset to ARDS diagnosis was 11.0 (IQR, 8.0–13.0). Up to 84.1% COVID-19-related ARDS patients demonstrated multiple organ injuries. The mortality rates were 41.9% and 85.7% in moderate and severe ARDS. The survival patients on invasive mechanical ventilation (IMV) had been intubated earlier since ARDS diagnosis than those who had not survived (5.5 median days, IQR 4.0-7.0 days versus 11.5 median days, IQR 6.0-14.0 days, P < 0.001). Males and all abnormal laboratory indices associated with the higher risk of ARDS (P0.05). The sensitivity analyses found that lymphocyte count of < 1000 per mm3 at hospital admission were still significantly associated with developing ARDS when adjusting for age and male gender (HR, 4.10; 95% CI, 2.40-7.10), and oxygenation index (OI) ratio < 150 were more likely to predict the intubation/death after age adjustment (HR, 2.50; 95% CI, 1.17-5.30). Conclusion: The SARS-CoV-2-caused ARDS was not the typical ARDS according to Berlin criteria. The alive patients with IMV had been intubated earlier since ARDS diagnosis than those who had not survived. We identified male gender and abnormal laboratory indices associated with the ARDS but were not linked with the intubation/death. Sensitivity analysis concluded lymphocyte count of < 1000 per mm3 could predict ARDS while OI ratio less than 150 could predict intubation/death.

Background: More evidence in understanding the heterogeneity of COVID-19-associated acute respiratory distress syndrome (ARDS) and in improving strategy to increase the survival from the critical patients intubated is always needed. The study aimed to comprehensively explore the features of COVID-19-associated ARDS and the features and outcomes between the early and late intubation groups. Methods: This retrospective cohort included 65 adult COVID-19 inpatients with ARDS at two hospitals in Hubei, China. The ARDS in these patients was diagnosed according to the Berlin criteria. We defined intubation within 7 days of ARDS diagnosis as ‘early’ intubation and that performed from the eighth day as ‘late’ intubation based on literatures. The outcomes were invasive mechanical ventilation and in-hospital death. The log-binomial regression models were used to explore the risk factors and the Kaplan-Meier statistic was used to estimate the risk of mortality. Results: The median number of days from symptom onset to ARDS diagnosis was 11.0 (IQR, 8.0–13.0). Up to 84.1% COVID-19-related ARDS patients demonstrated multiple organ injuries. The mortality rates were 41.9% and 85.7% in moderate and severe ARDS. The early intubation and the late intubation had the differences in days from symptom onset/hospital admission/ARDS diagnosis to intubation (P = 0.023, P = 0.011, P < 0.001). Compared with the early-intubation group, the late-intubation group showed less severity at admission (median oxygenation index 159.0 95% CI 134.0-203.0 vs. 133.9 95% CI 98.3-183.2), but required more aggressive therapies (ICU 80% vs. 70%, CRRT 50% vs. 10%, prone-position 50% vs. 30%, and ECMO 50% vs. 10%) and had higher risk to die at hospital (RR, 3.18; 95% CI 1.98-5.12). Conclusion: The ARDS caused by COVID-19 was not typical ARDS due to prolonged onset time, multiple organ injuries, and higher mortalities. The late-intubation group showed less severity at admission but higher risk of in-hospital death than the early-intubation group.

3D modeling technique has become a favorable tool for people to observe and analyze the world, and has been used widely in various trades. Geological body enrich mineral resources, and the spatial shape and petrophysical distributions of geological body are controlled by geological conditions. So 3D geological modeling under the control of complex geological conditions becomes the research emphasis. This article analyzes the uncertainty, complexity and diversity of geological body, and lists complex geological conditions controlling spatial shape and petrophysical distributions of geological body. And then 3D geological modeling method under the control of complex geological conditions is proposed, and corresponding modeling workflow is set up. Finally, taking 3D geological modeling of petroleum exploration and development for example, 3D geological model of Yulou oil formation, Jin-16 block, Liaohe oil-field, is built and some applications like 3D visualization of geological body are realized.

In this paper we propose a scheme for reach ability testing to obtain statement coverage in the dynamic testing of concurrent programs. The proposed scheme derives inputs from SYN-sequences obtained in reach ability testing and uses these inputs to perform reach ability testing multiple times in order to achieve statement-coverage testing for a concurrent program.

With the development of GIS, digital oilfield construction based on GIS becomes a hot research area. On the basis of reservoir description project, this paper carries out the exploratory research on the application of GIS in oilfield exploration and development, and builds the basic information platform for exploration and development. Basic data and geological maps are stored and managed in spatial database through spatial database engine. The platform realizes three information query means including querying from graph to attributive, querying from attributive to graph and querying from graph to graph, and achieves a high-efficiency graphic editing function. The platform also supplies automatic or semi-automatic thematic mapping functions for well section, distributive maps of reservoir property and sedimentary microfacies, etc. Taking into account the daily needs of geological work, the platform also offers data analysis and processing tools for reservoir property calculation, single well production analysis, etc. Simultaneously, on the basis of spatial analysis functions of GIS, the platform realizes aid decision support capabilities for petroleum exploration and development, such as drilling virtual well, generating arbitrary reservoir profile, etc.

Based on Geographic Information System(GIS) technology, the research of 3D geological modeling(3DGM) is carried out. The 3DGM method focused on complex geologic body is put forward, and modeling process is set up. First of all, according to the different strata, index layer of fault-block polygon is built. Then under the restraining of seismic interpretation surface and fault-block boundary, digital elevation model (DEM) tiles are built aiming at fault-block polygons in index layer. Based on index layer, DEM tiles are assembled into DEM of stratum aimed at index layer. Finally 3D structural model is built through overlaying DEM, and 3D geological model is generated based on 3D structural model. Taking Shu II district in the Liaohe Oilfield for example, 3D geological model of Dalinghe reservoir is successfully built based on this method. Visualization of model is realized through 3D GIS technology.

A two-dimensional Quadratic Boundary Element Method (QBEM) and a three-dimensional cubic Higher-order Boundary Element Method (HOBEM) are developed to study respectively the twodimensional and three-dimensional weakly-nonlinear wave-body interactions with/without forward speed within potential flow theory of an incompressible liquid. A direct method based on a triangular polar-coordinate system transformation for the evaluation of the Cauchy Principle Value (CPV) integrals for the diagonal terms of the influence matrix in the 3D HOBEM is presented. A numerical module based on the Fast Multipole Method (FMM) is developed, which can be used as an option to speed up the present 3D HOBEM solver. Both the operation count and the required memory of a FMM accelerated BEM is asymptotically O(N), where N is the total number of the unknowns. Suggestion on the selection of a proper matrix solver for a specific problem is given. A new approach based on domain decomposition using body-fixed coordinate system in the inner domain and the inertial reference frame in the outer domain is proposed for the weakly-nonlinear wave-body analysis. Consistent theoretical description of the new method based on second-order theory is presented. The new method does not require any derivatives on the right-hand sides of the body boundary conditions and thus avoid the mj -like terms and their derivatives. Furthermore, because the body boundary condition is formulated on the instantaneous position of the body, the resulting integral equations are valid for both smooth bodies and bodies with sharp corners. In order to improve the convergence of the second-order forces/moments on a body with sharp corners in the near-field approach, a re-formulation of the quadratic force is suggested. This re-formulation transfers the integrals on the body into the sum of two groups of integrals. The first group contains integrals on body surface with integrands whose singularities are weaker than that of the velocity square. The second group consists of regular integrals on the inner free surface and the control surface in the inner domain. A two-dimensional third-order numerical wave tank (NWT) is developed. The effect of the Stokes drift in the second-order solution is discussed. A two-time scale approach is proposed as a secularity (solvability) condition in order to avoid unphysical third-order results. The numerical results for the second-order diffraction/radiation of a horizontal semi-submerged circular cylinder are verified by some other analytical and numerical results. Comparisons with the experimental results are also made. The second-order wave-body interaction with/without the presence of a small forward speed for a three-dimensional floating body is studied by both the traditional method (if applicable) with a formulation in the inertial coordinate system and the new method with a formulation in the body-fixed coordinate system near the body. Both bodies without sharp corners and a truncated vertical circular cylinder with sharp corners are studied. Comparisons between the present numerical results with some other analytical and numerical results (if any) show good agreement. The influences of a small forward speed on the second-order wave loads on floating bodies are investigated. The complete third-order wave diffraction of a stationary three-dimensional body is studied by the time-domain HOBEM, which means that the solution contains not only the triple-harmonic effect but also the third-order contribution with fundamental frequencies of the incident waves. Careful convergence studies and alternative way of calculating the force have been made with very satisfactory results.