High Dynamic Movement Research Articles

#124 : Microtubule Stability is Associated with the Functional Activity of Mitochondria for the Mouse Preimplantation Embryo Development

Background and Aims: Mitochondria have a pivotal role in the quality of embryos and good development to a healthy embryo pregnancy. Also, mitochondrial dysfunction increases during the aging of the embryos. But there is still a debate about the main cause of mitochondrial dysfunction in the aged embryos. We investigate that effect of microtubule stabilizer (MTS) as Taxol, EpD and microtubule disturber (MTD) as VNB in the preimplantation embryo of the mouse. Method: We performed preimplantation embryo culture with MTS and MTD. Then we assess development ratio and mitochondria functional activity between control and MTS and MTD. We performed comparable analysis of mitochondrial motility between MTS treated and MTD treated embryos by confocal live imaging. Results: In the MTS treated embryos, well-developed embryos with microtubules formation were present in the ooplasm. However, in the MTD treated embryos group, less development and poor microtubule polymer formation was observed in the ooplasm. Microtubules was also demonstrated by depolymerization and the clustering form in the ooplasm of MTD treated embryos. The high dynamic movement of the cytoskeleton with a mitochondrion compared to the MTD treated embryos. Conclusion: Our data suggest that the new function of MTS as Taxol, EpD shows promoting competence of embryo development with enhanced activity of a mitochondrial function. Therefore, MTS is useful as a supplement in vitro culture media of embryos.

A High-Efficiency Searching Time Reduction Method for VCM Soft-Landing Operation During Chip Bonding

The chip precision bonding operation is a large-stroke high-speed and high-acceleration operation, which is usually realized by a voice-coil-motor (VCM). During the decelerating positioning to contact the chip, such high-dynamic movement could often accompanied by inertial vibration which may impact the chip. To achieve a gentle contacting, the VCM soft-landing method is widely used in bonding process, which designs a micro-searching-area to accommodate the inertial vibration, and starts up a low-speed uniform-motion once the bonding system stabilizes. To minimize the time consumed in the searching area, this work proposed a high-efficiency searching time reduction (HSTR) method. Specifically, during the entire inertial vibration, a dynamic uniform-motion actuation, which is conditionally planned for the VCM, starts the uniform-motion as early as possible, and arrives at the target position precisely when the vibration attenuation is completed. The start-up moment planning is determined by the inertial vibration cycle, while the actuation velocity planning is dynamically decided by the real-time inertial vibration energy. The HSTR method can perform a proper actuation to speed up the VCM soft-landing without affecting the gentle contacting. Together with theoretical verification of its implementation and effectiveness simulation, the HSTR method is validated experimentally with different displacements, velocities, and accelerations.

Comb-Search and Hierarchical-Clustering Based Doppler-Shift Acquisition for Space Communications

In space communications, the signal quality generally suffers due to long-distance transmission and high dynamic movement. Long-distance transmission causes a very low signal-to-noise ratio (SNR) and high dynamic movement causes a dynamic Doppler-shift on carrier frequency. To boost the signal component in SNR, multiple symbols over a long duration of time are accumulated, which is termed as long-term accumulation. However, during the long-term accumulation, the large acceleration and jerk result in a time-varying Doppler shift, thus dispersing the energy over a wide frequency range. In this paper, we propose a comb-search and hierarchical-clustering (CSHC) based Doppler-shift acquisition scheme, including the Generic CSHC algorithm and Iterative CSHC algorithm, to address the energy dispersion problem for space communications. In the Generic CSHC algorithm, the comb-search (CS) decreases the noise energy by a narrower CS-range while the hierarchical-clustering (HC) increases the signal energy by clustering multiple signal elements into one signal cluster. Then, the Iterative CSHC algorithm, which builds on the iterations of CS and HC, further decreases the noise energy and increases the signal energy. Simulations results verify that our proposed CSHC scheme significantly improves the acquisition probability, as compared with the existing schemes.

Dominance of Arcobacter in the white filaments from the thermal sulfidic spring of Fetida Cave (Apulia, southern Italy)

The thermal spring of Fetida Cave, a still active sulfuric acid cave opening at sea level and located in Santa Cesarea Terme, southeastern Salento (Apulia region, Southern Italy) hosts abundant floating white filaments. The white filaments were mainly composed of sulfur crystals surrounded by microbial mass of the phyla Epsilonbacteraeota, Proteobacteria, Bacteroidetes, and Patescibacteria. The most abundant genus in the white filaments collected from the waters in the innermost part of the cave dominated by sulfidic exhalations was Arcobacter. This abundance can be related to the higher concentration of sulfide dissolved in water, and low oxygen and pH values. Conversely, lower Arcobacter abundances were obtained in the filaments collected in the entrance and middle part of the cave, where sulfidic water mixes with seawater, as the cave is subjected to tides and the mixing of fresh (continental) with marine water. The geochemical analysis of water and atmospheric gases confirmed these environmental constraints. In fact, the highest concentrations of H2S in the air and water were recorded closest to the spring upwelling in the innermost part of the cave, and the lowest ones near the cave entrance. The metabolic versatility of Arcobacter might provide a competitive advantage in the colonization of water bodies characterized by high sulfide, low oxygen, and dynamic fluid movement.

Clock tuning technique for a disciplined high medium–long-stability GNSS oscillator with precise clock drifts for LEO users

A crucial issue of low earth orbit (LEO) navigation augmentation satellite constellation is to obtain a satellite clock of high medium–long stability (i.e., averaging time of 10–10,000 s) using a disciplined oscillator to reduce satellite size, weight, power consumption and cost, instead of using a large, heavy and expensive space atomic clock. To resolve this difficulty, we propose a new global navigation satellite system (GNSS) clock discipline technique via a stand-alone GNSS receiver. Consequently, high medium–long stability can be attained with the disciplined receiver oscillator. Based on the Doppler measurements calculated from carrier phases, precise clock drifts of the receiver oscillator are derived. According to the motion state of the LEO GNSS receiver, a precise clock drift estimation model is chosen to have good adaptability to the receiver's high dynamic movement. Then, the receiver oscillator is properly tuned to its nominal frequency at each epoch without loss of lock. An automatic closed-loop frequency control system using a third-order frequency-locked loop filter is proposed to periodically compensate the instantaneous frequency offsets of the user clock with respect to its nominal frequency. A nonlinear frequency steering method is proposed to overcome the receiver lost lock problem during the oscillator discipline process. The correctness and effectiveness of the proposed clock tuning technique were numerically verified with MATLAB first. Then, the oscillator discipline performances were tested with a VCH-1008 passive hydrogen maser, a LEO GNSS receiver and a PicoTime clock stability analyzer. With static real GPS data of a static receiver as well as with hardware simulated data of a LEO receiver, both the medium-term and long-term frequency stabilities of the disciplined oscillator were confirmed. Finally, the proposed oscillator discipline technique was implemented in a self-developed LEO GNSS receiver. A high-quality voltage-controlled crystal oscillator mounted on an onboard LEO receiver was used for our test both in a static situation and in a LEO dynamic environment. The experiment results show that the overlapping Allan deviation of the disciplined GNSS oscillator could be less than 7E-12 over periods of 1 to 4,000 s in both the static situation and the LEO moving situation for a 1070 km orbit with 1 Hz epoch sampling rate at the testing stage.

Navigation Engine Design for Automated Driving Using INS/GNSS/3D LiDAR-SLAM and Integrity Assessment

Automated driving has made considerable progress recently. The multisensor fusion system is a game changer in making self-driving cars possible. In the near future, multisensor fusion will be necessary to meet the high accuracy needs of automated driving systems. This paper proposes a multisensor fusion design, including an inertial navigation system (INS), a global navigation satellite system (GNSS), and light detection and ranging (LiDAR), to implement 3D simultaneous localization and mapping (INS/GNSS/3D LiDAR-SLAM). The proposed fusion structure enhances the conventional INS/GNSS/odometer by compensating for individual drawbacks such as INS-drift and error-contaminated GNSS. First, a highly integrated INS-aiding LiDAR-SLAM is presented to improve the performance and increase the robustness to adjust to varied environments using the reliable initial values from the INS. Second, the proposed fault detection exclusion (FDE) contributes SLAM to eliminate the failure solutions such as local solution or the divergence of algorithm. Third, the SLAM position velocity acceleration (PVA) model is used to deal with the high dynamic movement. Finally, an integrity assessment benefits the central fusion filter to avoid failure measurements into the update process based on the information from INS-aiding SLAM, which increases the reliability and accuracy. Consequently, our proposed multisensor design can deal with various situations such as long-term GNSS outage, deep urban areas, and highways. The results show that the proposed method can achieve an accuracy of under 1 meter in challenging scenarios, which has the potential to contribute the autonomous system.

Fast Acquisition Scheme of the Spread Spectrum Signals for Satellite Communications

A four-channel parallel acquisition scheme combining partial matched filters and fast Fourier transforms (PMF-FFT) is proposed for the fast acquisition of the spread spectrum signals in satellite communication terminals installed into the offshore buoys with the high-dynamic movement, which is used tofinish data communication missions between the buoys and the satellite. Compared with traditional code phase FFT scheme, the new scheme reduces the maximum acquisition time to 26.5% and the maximum computation amount to 46.9%. It also improves about 4 times in the frequency resolution and 1.6 dB in the receiving sensitivity at the expense of computation complexity compared to PMF-FFT scheme. The parallel PMF-FFT scheme greatly reduces scallop loss, thus ensuring acquisition sensitivity. The parallel PMF-FFT scheme within the satellite communication terminal can ensure the fast and stable tracking of satellite signal by the violently moving antenna within 20 ms under level-4 sea state.

Robust SINS/GNSS Integration Method for High Dynamic Applications

As high dynamic movement is always accompanied by colored noise which lacks of mathematical model, traditional Kalman filtering based on an assumption of white Gaussian noise always faces serious divergence. To enhance the performance in high dynamic environment with uncertain colored noise, a kind of robust filtering based on H-infinity technology is developed . State model of the algorithm is derived from SINS error propagation . Both p osition and velocity error s are used as the measurements. A simulation system which includes a tri-axial turntable and a GNSS signal simulator is used to verify the integration design under high dynamic environment . S imulation results proved that both the accuracy and robustness of the integration design ha ve been improved significantly. DOI: http://dx.doi.org/10.11591/telkomnika.v13i2.6876

Doppler-Aided GNSS Position Estimation With Weighted Least Squares

In contrast to carrier-phase measurements, receiver-generated Doppler measurements have much better availability, even in severe urban canyons or high-dynamic movement applications, while providing centimeter-level precision. Thus, the Doppler-aided approach may improve the positioning accuracy of the receiver. Some Kalman-filter-based applications have been developed in recent years, but the theoretical error analysis is still missing. In this paper, we propose a model-free Doppler-aided position estimation approach. The Doppler measurements are modeled together with the code pseudoranges and then solved as a weighted least square (WLS) problem. In addition, we analyze the lower bound of errors of the approach based on the Cramer-Rao bound (CRB). Simulation results and the error analysis show that the proposed approach may improve accuracy in position estimation.

Dynamic long axis for ultra-precision machining of optical linear structures

Currently, fly cutting is the most popular manufacturing technology for the machining of planar groove structures. The disadvantage of this technology is the long machining time. A promising alternative technology for the machining of planar grooves is planing. The main disadvantage of planing in comparison to fly cutting is the limitation of conventional precision axes concerning a high dynamic movement. Regarding to this aspect the Fraunhofer IPT has developed a precise linear axis. It allows high dynamic movements by using an impulse decoupling system (AiF-FV-Nr.: 13,270 N). The paper describes the mechanical setup and the development and optimization of the mechanical main component. The detailed simulation of the drive system (including motor control loop and impulse decoupling system), results of static and dynamic measurements and test machining results are presented.

Environmentalism, Development, and Participation on Palawan Island, Philippines

On Palawan Island, Philippines, known for its high biodiversity and dynamic environmental movement, development, participation, and conservation have been enveloped by the twin discourses of environmentalism and sustainable development. This essay considers environmental policy on Palawan and several case studies of sustainable development projects that emphasize community-based resource management (CBRM). Recent critiques suggest that CBRM has not been successful because communities lack self-sufficiency and claims of “local participation” are merely rhetorical. We argue that analyses of CBRM should consider three aspects of Philippine environmentalism: whether rhetoric regarding resource management matches reality in the eyes of local residents; the overlapping roles of government and nongovernmental organizations (NGOs); and multiplex relationships of NGOs with local communities. Our findings suggest that despite some difficulties, stronger NGO roles in CBRM have generally resulted in better environmental protection, and through relationships with NGOs, communities in the Philippines can indeed take action to serve their own best interests.

Growth and mechanism of filamentous‐sulfur formation by Candidatus Arcobacter sulfidicus in opposing oxygen‐sulfide gradients

Studies were conducted in opposing gradients of oxygen and sulfide in microslide capillaries to (i) characterize the chemical microenvironment preferred by Candidatus Arcobacter sulfidicus, a highly motile, sulfur-oxidizing bacterium that produces sulfur in filamentous form, and (ii) to develop a model describing the mechanism of filamentous-sulfur formation. The highly motile microorganisms are microaerophilic, with swarms effectively aggregating within oxic-anoxic interfaces by exhibiting a chemotactic response. The position of the band was found to be largely independent of the sulfide concentration as it always formed at the oxic-anoxic interface. Flux calculations based on steady state gradients of oxygen and sulfide indicate that sulfide is incompletely oxidized to sulfur, in line with the formation of filamentous sulfur by these organisms. It is proposed that Candidatus Arcobacter sulfidicus effectively competes with other sulfur-oxidizing bacteria in the environment by being able to tolerate higher concentrations of hydrogen sulfide (1-2 mM) and by possessing the ability to grow at very low oxygen concentrations (1-10 muM). The formation of mat-like structures from filamentous sulfur appears to be a population mediated effort allowing these organisms to effectively colonize environments characterized by high sulfide, low oxygen and dynamic fluid movement.