16 research outputs found
A Method for Detecting and Adjusting Systematic Errors of Singlebeam Sounding Data Acquired in a Grid Pattern*
Sound Velocity Profile (SVP) inversion through correcting the terrain distortion
In this paper, mode vectors are obtained via the Empirical Orthogonal Function (EOF) based on real Sound Velocity Profiles (SVP) measurements. Through correcting the terrain distortion, reconstructed coefficients of SVPs are determined by Genetic Algorithm (GA) and then the inversion result of the SVP is obtained. The conclusions show that the terrain distortion caused by sound velocity errors can be effectively corrected by the inversion result of the SVP. Using this process, the accuracy and processing efficiency of multi-beam bathymetry data can be significantly improved.En este artículo, se obtienen los vectores de forma a través de la Función Empírica Ortogonal (EOF) basada en mediciones reales de los Perfiles de la Velocidad del Sonido (SVP). Mediante la corrección de la distorsión del terreno, los coeficientes reconstruidos de los SVPs son determinados por el Algoritmo Genético (AG) y posteriormente se obtiene el resultado de la inversión del SVP. Las conclusiones muestran que la distorsión del terreno causada por errores de velocidad del sonido puede corregirse eficazmente mediante el resultado de la inversión del SVP. Utilizando este proceso, la exactitud y la eficiencia del procesado de los datos de batimetría multihaz pueden mejorarse significativamente.Cet article décrit la décomposition en vecteurs propres via les fonctions empiriques orthogonales (EOF) des mesures des profils de vitesse du son (SVP). La correction des distorsions de terrain permet de déterminer des coefficients reconstruits des SVP à l’aide d’un algorithme génétique (AG), puis le résultat de l’inversion du SVP est obtenu. Les conclusions montrent que les distorsions de terrain causées par les erreurs de vitesse du son peuvent être effectivement corrigées par le résultat de l’inversion du SVP. A l’aide de ce processus, la précision et l’efficacité du traitement des données bathymétriques multifaisceaux peuvent être améliorées de façon importante
Examining the generalizability of research findings from archival data
This initiative examined systematically the extent to which a large set of archival research findings generalizes across contexts. We repeated the key analyses for 29 original strategic management effects in the same context (direct reproduction) as well as in 52 novel time periods and geographies; 45% of the reproductions returned results matching the original reports together with 55% of tests in different spans of years and 40% of tests in novel geographies. Some original findings were associated with multiple new tests. Reproducibility was the best predictor of generalizability—for the findings that proved directly reproducible, 84% emerged in other available time periods and 57% emerged in other geographies. Overall, only limited empirical evidence emerged for context sensitivity. In a forecasting survey, independent scientists were able to anticipate which effects would find support in tests in new samples
Technical Progress and Development Directions of Oceanic Spatial Information Datum
This paper briefly analyzes the basic development and technical situation of oceanic spatial information datum, reviews the main processes of oceanic vertical datum and correlative oceanic tidal study, such as improvement and perfect methods of determining tidal station vertical datum, realizing form of vertical datum controlled by tidal station, effect on maintaining vertical datum by long-term tidal station, oceanic tidal model establishing, and also construction and transformation of tidal datum, and then forecasts the key development directions of oceanic spatial information datum on high-accuracy marine position service, vertical datum and the transferring model refinement and spatial datum application
Semi-parametric adjustment model methods for positioning of seafloor control point
This paper focuses on solving the problem of seafloor control point absolute positioning with low vertical accuracy based on the survey ship sailing circle. The method of dealing with the systematic error based on semi-parametric adjustment model was proposed. Firstly, the influence of sound speed change on ranging error is analyzed. Secondly, a semi-parametric adjustment model for determining three-dimensional coordinates of underwater control points was established. And respectively proposed solutions under two different conditions, the observation duration is an integral multiple or non-integer multiple of the long-period term of the ranging error. Simulation experiment results show that this method can obviously improve the accuracy of vertical solution of seafloor control point compared with difference technique and least square method when internal waves exist and observation duration is less than an integer multiple of the long-period term of the ranging error
Analysis of some problems in classification of seabed bottom characteristics using acoustic backscattering intensity
The backscattering intensity collected by multi beam sonar system and scanning sonar system can be used to classify seabed bottom characteristics. However, there are many problems that have not been solved in the practical application. This paper attempts to sort out and analyze the problems encountered in the classification process and put forward some solutions. The relationship among acoustic image, seabed topography and sediment is analyze
Effect of Parameters of HRS Process on Microstructure of DZ466 Ni-based Superalloy
The influences of withdrawal rate and mold heater zone temperature during high rate solidification (HRS) on the microstructures were investigated. As the results, the primary dendritic spacing, the size of γ′ phase particles and carbides are decreased with the increase of the withdrawal rate or mold heater zone temperature. As the withdrawing goes on, the primary dendritic spacing and the size of γ′ phase particles are increased, and the heat emission efficiency of HRS process is decreased. The results show that fine dendrite and γ′ phase can be achieved with the withdrawal of 8 mm/min and mold heater zone temperature of 1520 ℃/1530 ℃, which is benefit to improve the properties of DZ466 alloy
Caspase-9 inhibition triggers Hsp90-based chemotherapy-mediated tumor intrinsic innate sensing and enhances antitumor immunity
Background Antineoplastic chemotherapies are dramatically efficient when they provoke immunogenic cell death (ICD), thus inducing an antitumor immune response and even tumor elimination. However, activated caspases, the hallmark of most cancer chemotherapeutic agents, render apoptosis immunologically silent. Whether they are dispensable for chemotherapy-induced cell death and the apoptotic clearance of cells in vivo is still elusive.Methods A rational cell-based anticancer drug library screening was performed to explore the immunogenic apoptosis pathway and therapeutic targets under apoptotic caspase inhibition. Based on this screening, the potential of caspase inhibition in enhancing chemotherapy-induced antitumor immunity and the mechanism of actions was investigated by various cells and mouse models.Results Heat shock protein 90 (Hsp90) inhibition activates caspases in tumor cells to produce abundant genomic and mitochondrial DNA fragments and results in cell apoptosis. Meanwhile, it hijacks Caspase-9 signaling to suppress intrinsic DNA sensing. Pharmacological blockade or genetic deletion of Caspase-9 causes tumor cells to secrete interferon (IFN)-β via tumor intrinsic mitochondrial DNA/the second messenger cyclic GMP–AMP (cGAS) /stimulator of interferon genes (STING) pathway without impairing Hsp90 inhibition-induced cell death. Importantly, both Caspase-9 and Hsp90 inhibition triggers an ICD, leading to the release of numerous damage-associated molecular patterns such as high-mobility group box protein 1, ATP and type I IFNs in vitro and remarkable antitumor effects in vivo. Moreover, the combination treatment also induces adaptive resistance by upregulating programmed death-ligand 1 (PD-L1). Additional PD-L1 blockade can further overcome this acquired immune resistance and achieve complete tumor regression.Conclusions Blockade of Caspase-9 signaling selectively provokes Hsp90-based chemotherapy-mediated tumor innate sensing, leading to CD8+ T cell-dependent tumor control. Our findings implicate that pharmacological modulation of caspase pathway increases the tumor-intrinsic innate sensing and immunogenicity of chemotherapy-induced apoptosis, and synergizes with immunotherapy to overcome adaptive resistance
Retinoic Acid Receptor Is a Novel Therapeutic Target for Postoperative Cognitive Dysfunction
Postoperative cognitive dysfunction (POCD) is a clinical syndrome characterizing by cognitive impairments in the elderly after surgery. There is limited effective treatment available or clear pathological mechanisms known for this syndrome. In this study, a Connectivity Map (CMap) bioinformatics model of POCD was established by using differently expressed landmark genes in the serum samples of POCD and non-POCD patients from the only human transcriptome study. The predictability and reliability of this model were further supported by the positive CMap scores of known POCD inducers and the negative CMap scores of anti-POCD drug candidates. Most retinoic acid receptor (RAR) agonists were negatively associated with POCD in this CMap model, suggesting that RAR might be a novel target for POCD. Most importantly, acitretin, a clinically used RAR agonist, significantly inhibited surgery-induced cognitive impairments and prevented the reduction in RARα and RARα-target genes in the hippocampal regions of aged mice. The study denotes a reliable CMap bioinformatics model of POCD for future use and establishes that RAR is a novel therapeutic target for treating this clinical syndrome
Modified cathode-electrolyte interphase toward high-performance batteries
A stable and uniform cathode-electrolyte interphase (CEI) is extremely important for rechargeable batteries with high energy densities and long life cycles. The CEI greatly influences the electrochemical reactions at the interphase while stabilizing the cathode\u27s structure. Because of the complexity of the interfacial reaction, an overall picture of CEI evolution and effective analysis methods is absent in the field. Herein, the formation and evolution mechanism of the CEI in rechargeable batteries are reviewed based on the CEI studies. Diverse advanced characterization methods for the interfacial reaction are also summarized. Subsequently, modified strategies to enhance the stability of the CEI are introduced, such as CEI-forming additives in electrolytes, localized high-concentration electrolytes, artificial CEIs, and solid-state electrolyte engineering. Finally, challenges and future directions for the CEI are proposed. We hope this review sheds light on future research on CEI layers