The Influence of Carrier's Attitude and the Position Reduction in Multibeam Echosounding and Airborne Laser Depth Sounding

Having finished the development of the multibeam echosounding system, China is making a great effort to develop an airborne laser depth sounding system. According to the principle of the two kinds of sounding system mentioned above, a series of position reduction formulas and their error equations are developed in this paper. The dynamic effect of marine sounding, i.e., the influence of carrier's attitude, is taken into full account in developing the equations. Finally, the real parameters of the two sounding systems developed by China are used to calculate the position reductions and their accuracies at different heading angles. The results show that the accuracies of depths and positions in multibeam echosounding and airborne laser depth sounding are dependent not only on their own sensors but also on the additional sensors

Spine surgeon specialty differences in single-level percutaneous kyphoplasty

Background Percutaneous kyphoplasty (PKP) is a procedure performed by a spine surgeon who undergoes either orthopedic or neurosurgical training. The relationship between short-term adverse outcomes and spine specialty is presently unknown. To compare short-term adverse outcomes of single-level PKP when performed by neurosurgeons and orthopedic surgeons in order to develop more concretely preventive strategies for patients under consideration for single-level PKP. Methods We evaluated patients who underwent single-level PKP from 2012 to 2014 through the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP). We used univariate analysis and multivariate logistic regression to assess the association between spine surgeon specialty and short-term adverse events, including postoperative complication and unplanned readmission, and to identify different independent risk predictors between two specialties. Results Of 2248 patients who underwent single-level PKP procedure, 1229 patients (54.7%) had their operations completed by a neurosurgeon. There were no significant differences in the development of the majority of postoperative complications and the occurrence of unplanned readmission between the neurosurgical cohort (NC) and the orthopedic cohort (OC). A difference in the postoperative blood transfusion rate (0.7% NS vs. 1.7% OC, P = 0.039) was noted and may due to the differences in comorbidities between patients. Multivariate regression analysis revealed different independent predictors of postoperative adverse events for the two spine specialties. Conclusions By comparing a large range of demographic feature, preoperative comorbidities, and intraoperative factors, we find that short-term adverse events in single-level PKP patients does not affect by spine surgeon specialty, except that the OC had higher postoperative blood transfusion rate. In addition, the different perioperative predictors of postoperative complications and unplanned readmissions were identified between the two specialties. These findings can lead to better evidence-based patient counseling and provide valuable information for medical evaluation and potentially devise methods to reduce patients’ risk

Efficacy and safety of erythropoietin for traumatic brain injury

Background Recent studies regarding the effects of erythropoietin (EPO) for treating traumatic brain injury (TBI) have been inconsistent. This study conducts a meta-analysis of randomized controlled trials (RCTs) to assess the safety and efficacy of EPO for TBI patients at various follow-up time points. Methods A literature search was performed using PubMed, Web of Science, MEDLINE, Embase, Google Scholar and the Cochrane Library for RCTs studying EPO in TBI patients published through March 2019. Non-English manuscripts and non-human studies were excluded. The assessed outcomes include mortality, neurological recovery and associated adverse effects. Dichotomous variables are presented as risk ratios (RR) with a 95% confidence interval (CI). Results A total of seven RCTs involving 1197 TBI patients (611 treated with EPO, 586 treated with placebo) were included in this study. Compared to the placebo arm, treatment with EPO did not improve acute hospital mortality or short-term mortality. However, there was a significant improvement in mid-term (6 months) follow-up survival rates. EPO administration was not associated with neurological function improvement. Regarding adverse effects, EPO treatment did not increase the incidence of thromboembolic events or other associated adverse events. Conclusions This meta-analysis indicates a slight mortality benefit for TBI patients treated with EPO at mid-term follow-up. EPO does not improve in-hospital mortality, nor does it increase adverse events including thrombotic, cardiovascular and other associated complications. Our analysis did not demonstrate a significant beneficial effect of EPO intervention on the recovery of neurological function. Future RCTs are required to further characterize the use of EPO in TBI

Integrated Data Processing for Multi-Satellite Missions and Recovery of Marine Gravity Field

In order to eliminate the inconsistency of the existing data from multi-satellite missions, we propose a new method for optimal combination of altimeter data. In our data management system, the crossover adjustment is modified to two-step processing based on the a posteriori compensation theory of error; i.e., the crossover adjustment of condition equations is made in the first step, and the filtering and prediction of adjustment corrections done along each single pass in the second step. Using the new approach can simplify greatly the computational procedure of crossover adjustment, and the stability and reliability of its solution can be expected. The new method can be used for both local and global crossover adjustment problems. Finally, a practical altimeter dataset from Geosat, ERS-1, ERS-2, and TOPEX/POSEIDON (T/P) is used as a case study to prove the efficiency of the integrated data processing method

Effect of External Disturbing Gravity Field on Spacecraft Guidance and Surveying Line Layout for Marine Gravity Survey

Centred on the support requirement of flying track control for a long range spacecraft, a detail research is made on the computation of external disturbing gravity field, the survey accuracy of gravity anomaly on the earth' surface and the program of surveying line layout for marine gravity survey. Firstly, the solution expression of navigation error for a long range spacecraft is analyzed and modified, and the influence of the earth's gravity field on flying track of spacecraft is evaluated. Then with a given limited quota of biased error of spacecraft drop point, the accuracy requirement for calculating the external disturbing gravity field is discussed and researched. Secondly, the data truncation error and the propagated data error are studied and estimated, and the quotas of survey resolution and computation accuracy for gravity anomaly on the earth' surface are determined. Finally, based on the above quotas, a corresponding program of surveying line layout for marine gravity survey is proposed. A numerical test has been made to prove the reasonableness and validity of the suggested program

Research and Evaluation on Key Technological Target System for Marine and Airborne Gravity Surveys

Technological standard is an important scientific basis for marine and airborne gravity surveys. In accordance with the lack of the present specifications to reflect the trend of the times for marine and airborne gravity surveys,a detail analysis and research is made on key targets, such as the density of surveying line layout, survey accuracy, space resolution, zero drift and dynamic repeatability of air-sea gravimeter,etc. An evaluation system of survey accuracy targets including root mean square of errors(RMS),systematic error and mean error for marine and airborne gravity surveys is suggested. And an evaluation system of stability targets including calibration accuracy of scale value, total month zero drift, RMS of nonlinear month drift and limited deviation of nonlinear month drift is proposed. The methods of testing and evaluating the above technological targets are introduced. And some key mathematic models about reduction of observed values for marine gravity survey,Eötvös correction for airborne gravimetry,platform tilt correction and evaluation of survey accuracy for air-sea-borne gravimetry are analyzed and modified. The obtained conclusions provide useful theoretical support for the revision of existing specifications for future civil-military inosculation of marine and airborne gravity surveys