Kinetic isolation tether experiment

Progress was made on the analysis of tether damping and on experimentation of the control system on the laboratory simulator. The damping analysis considers the dynamics of a long tether connecting two spacecraft in Earth orbit, one of the spacecraft having dominant mass. In particular, it considers the material damping of the tether. The results show that, with properly chosen tether material and braiding structure, longitudinal vibration of the tethered system is well damped. A particularly effective method of implementing attitude control for tethered satellites is to use the tether tension force to generate control torques by moving the tether attach point relative to the satellite center of mass. A scaled, one dimensional laboratory simulation of the KITE mission was built and preliminary experiments of the proposed attitude control system were performed. The simulator was built to verify theoretical predictions of attitude controllability, and to investigate the technological requirements in order to implement this concept. A detailed description of the laboratory apparatus is provided, and in addition, the results of the preliminary experiments are presented and discussed

The Relationship between Motivation and Academic Performance in Chiropractic Students

This study aimed to investigate the relationship between motivation and academic performance in chiropractic students. This was a cross-sectional study. Three hundred and sixty-two students were recruited from the 1st and 3rd quarters during the 2017-2018 academic year. Out of 362 students, 305 completed the Inventory of School Motivation (ISM). Total scores from the 1st quarter General Anatomy course and the 3rd quarter Immunology/Endocrinology course were used to measure the 1st quarter and 3rd quarter academic performance, respectively. The mean total motivation score for all students was 28.40 ± 3.79 (mean ± SD). There was no signi?cant difference in total motivation score between students in the two quarters (p > .05). The mean of the 1st quarter praise scores was statistically significantly higher than those of the 3rd quarter (p < .05). The means of three motivation subscale scores for females were signi?cantly higher than that for males (task, effort, and praise, p < .05) while the mean competition score for males was signi?cantly higher than that for females (p < .01). The linear analysis demonstrated a weak but statistically significant correlation of task (r = .11, p < .05) and effort (r = .13, p < .05) with academic performance indicating that task and effort were minor predictors of academic outcome (p < .05).There was a weak, but statistically significant positive correlation between the three motivation subscales and academic performance. Female students scored significantly higher on three motivation subscales while males scored higher on one

The Law of Iterated Logarithm for Autoregressive Processes

This paper mainly discusses some dynamics asymptotic properties of autoregressive processes. By using the m-dependence of random variables, we prove the least squares (LS) estimator of the unknown parameters satisfies the law of iterated logarithm

Circ_0075825 promotes gastric cancer progression via adsorbing miR-432-5p to modulate SOX9

Methods: Circ_0075825 expression in adjacent tissues and GC tissues was evaluated by bioinformatics method and quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR). How circ_0075825 regulated GC cell growth, migration, invasion, and apoptosis were investigated by cell counting kit-8 assay, transwell assay and flow cytometry. The targeted interplays among circ_0075825, and miR-432-5p and Sex-Determining Region Y-related high-mobility group box 9 (SOX9) were explored by bioinformatics analysis and luciferase reporter gene assay. The regulatory effects of circ_0075825 and miR-432-5p on SOX9 protein expression were probed by western blot. Results: Circ_0075825 expression was raised in GC tissues and cell lines. Circ_0075825 overexpression promoted the proliferative, migrative and invasive abilities of GC cells, while inhibiting apoptosis, while depletion of circ_0075825 suppressed the malignant biological behaviors of GC cells. SOX9 was identified as one of the direct target genes of miR-432-5p, and circ_0075825 repressed the expression of miR-432-5p, to induce the expression of SOX9. Furthermore, miR-432-5p overexpression counteracted the promoting effect of circ_0075825 on the malignancy of GC cells. Conclusion: Circ_0075825 promotes GC progression via sponging miR-432-5p to regulate SOX9 expression level, and it may be a novel therapeutic target for treating GC

Homogenizing microwave illumination in thermoacoustic tomography by a linear-to-circular polarizer based on frequency selective surfaces

A circularly polarized antenna, providing more homogeneous illumination compared to a linearly polarized antenna, is more suitable for microwave induced thermoacoustic tomography (TAT). The conventional realization of a circular polarization is by using a helical antenna, but it suffers from low efficiency, low power capacity, and limited aperture in TAT systems. Here, we report an implementation of a circularly polarized illumination method in TAT by inserting a single-layer linear-to-circular polarizer based on frequency selective surfaces between a pyramidal horn antenna and an imaging object. The performance of the proposed method was validated by both simulations and experimental imaging of a breast tumor phantom. The results showed that a circular polarization was achieved, and the resultant thermoacoustic signal-to-noise was twice greater than that in the helical antenna case. The proposed method is more desirable in a waveguide-based TAT system than the conventional method