RESUMEN
Considering that the terrain-aided navigation (TAN) system based on iterated closest contour point (ICCP) algorithm diverges easily when the indicative track of strapdown inertial navigation system (SINS) is large, Kalman filter is adopted in the traditional ICCP algorithm, difference between matching result and SINS output is used as the measurement of Kalman filter, then the cumulative error of the SINS is corrected in time by filter feedback correction, and the indicative track used in ICCP is improved. The mathematic model of the autonomous underwater vehicle (AUV) integrated into the navigation system and the observation model of TAN is built. Proper matching point number is designated by comparing the simulation results of matching time and matching precision. Simulation experiments are carried out according to the ICCP algorithm and the mathematic model. It can be concluded from the simulation experiments that the navigation accuracy and stability are improved with the proposed combinational algorithm in case that proper matching point number is engaged. It will be shown that the integrated navigation system is effective in prohibiting the divergence of the indicative track and can meet the requirements of underwater, long-term and high precision of the navigation system for autonomous underwater vehicles.
RESUMEN
In recent years, coinfection of tuberculosis (TB) and parasitosis in humans is an emerging problem in coendemic areas, which has been increasingly highlighted in developing countries. However, there is limited information about the prevalence of Toxoplasma gondii infection in TB patients. Therefore, through a case-control study, 924 TB patients hospitalized for diacrisis or treatment in northeastern and eastern China, and 924 control subjects from the general population of the same region matched with gender, age, and residence were examined for the presence of IgG and IgM antibodies to T. gondii and associated sociodemographic and behavioral characteristics in a population of TB patients. Seroprevalence of IgG antibodies to T. gondii in TB patients (122/924, 13.2%) was significantly higher than control subjects (90/924, 9.7%) (p = 0.019), and 26 (2.8%) TB patients and 19 (2.1%) controls were positive for anti-T. gondii IgM antibodies (p = 0.291), respectively. Multivariate analysis showed that T. gondii infection was associated with keeping cats at home, presence of stray cats, and consumption of raw/undercooked meat. The present study first revealed the seroprevalence of T. gondii infection in TB patients in China. Moreover, parasitological surveys should be regularly carried out among TB patients, aiming to prevent the possibility of severe toxoplasmosis.