Enumeration of spanning trees in a pseudofractal scale-free web

Spanning trees are an important quantity characterizing the reliability of a network, however, explicitly determining the number of spanning trees in networks is a theoretical challenge. In this paper, we study the number of spanning trees in a small-world scale-free network and obtain the exact expressions. We find that the entropy of spanning trees in the studied network is less than 1, which is in sharp contrast to previous result for the regular lattice with the same average degree, the entropy of which is higher than 1. Thus, the number of spanning trees in the scale-free network is much less than that of the corresponding regular lattice. We present that this difference lies in disparate structure of the two networks. Since scale-free networks are more robust than regular networks under random attack, our result can lead to the counterintuitive conclusion that a network with more spanning trees may be relatively unreliable.Comment: Definitive version accepted for publication in EPL (Europhysics Letters

Square Root Cubature Kalman Filter-Kalman Filter Algorithm for Intelligent Vehicle Position Estimate

AbstractA new filtering algorithm, adaptive square root cubature Kalman filter-Kalman filter (SRCKF-KF) is proposed to reduce the problems of amount of calculation, complex formula-transform, low accuracy, poor convergence or even divergence. The method uses cubature Kalman filter (CKF) to estimate the nonlinear states of model while its linear states are estimated by the Kalman filter (KF). The simulation and practical experiment results show that, compared to the extended Kalman filter (EKF) and unscented Kalman filter (UKF). The modified filter not only enhances the numerical stability, guarantees positive definiteness of the state covariance, but also increases accuracy, which has high practicability

An experimental study of the natural characteristics of the wheeled and the tracked self-propelled guns

With wheeled and tracked self-propelled guns as research object, the study carries out the experimental modal analysis by using traditional method of hammering and operational modal analysis method, and obtains low-order natural frequency of the guns, and thus lays the foundation for further research on the vibration characteristics of wheeled and tracked self-propelled guns. By contrasting the low-order natural characteristics of wheeled and tracked self-propelled guns, conclusions can draw as the following: the modal shapes (from low to high) of wheeled and tracked self-propelled guns are pitch, translation and roll; when the modal shapes are identical, the natural frequency of tracked self-propelled guns is greater than that of wheeled self-propelled guns, which accords with the test results of the gun’s suspension equivalent stiffness; for wheeled self-propelled guns, an accurate measure of the gun’s natural characteristics is feasible by either the traditional or the operational modal analysis method. When it comes to tracked self-propelled guns, the operational modal analysis method is more accurate

Research on measuring method of the angular displacement of muzzle vibration

The angular displacement of the muzzle vibration has importance influence on the firing dispersion of gun. In order to solve the measuring problem on the angular displacement of the muzzle vibration in firing environment, a kind of measuring method of the angular displacement of the muzzle vibration based on the laser and the triangle principle was presented, and its measuring system was developed. The laser beam was sent by a laser. After the laser beam was reflected by a reflector on muzzle, the reflective beam was received by the position sensitive detector (PSD). Combining the optical distance parameter and the triangle relation, the angular displacement of the muzzle vibration could be obtained. The measuring error analysis of the system and the verification of the firing environment in shooting range were made. The performances of the measuring system were that the measuring range of the angular displacement was ±35', its angle resolution was 0.1', its relative errors under the different illumination conditions were less than 2 %. The measuring system can meet the needs of the gun measurement

Effects of doe-litter separation on intestinal bacteria, immune response and morphology of suckling rabbits

[EN] Gut development is stimulated by exposure to microorganisms, especially early-life microbial exposure. This study aimed to investigate whether doe-litter separation, which is performed in many rabbit farms, affects this exposure and therefore inhibits the development of intestinal system in suckling rabbits. Immediately after parturition, Rex rabbit does (n=16) were adjusted to 8 kits per litter and divided into doe-litter separation (DLS) group and doe-litter together (DLT) group based on the conditions of the does. One healthy kit per litter was selected and sacrificed at 7 d, 14 d, 21 d and 28 d of age, and the number of total bacteria, Escherichia coli and Bacteroides-Prevotella, expression of interleukin 6 (IL-6) and interleukin 10 (IL-10) in duodenum and caecum were investigated by real-time polymerase chain reaction. The morphological parameters of duodenum and vermiform appendix were also measured. Our results showed that doe-litter separation affected the number of intestinal bacteria. At 7 d of age, except for caecal Escherichia coli, the number of the investigated bacteria was decreased by doe-litter separation (P<0.05). But 1 wk later, only the number of total bacteria and Bacteroides-Prevotella in caecal content (P<0.05) and Escherichia coli in duodenal content from DLS kits (P<0.05) were still lower than those from DLT kits. After being provided with supplementary food for 7 d, DLS kits had fewer total bacteria in caecal content (P<0.05) and fewer E. coli in duodenal content (P<0.01) than DLT kits. After growing to 28 d of age, kits in DLS group still tended to have fewer total bacteria in caecal content, and expression of IL-10 and secretion of secretory IgA (sIgA) in vermiform appendix in DLS group was obviously lower than kits in DLT group (P<0.05). The villus height:crypt depth ratio in duodenum at 3rd wk and 4th wk was decreased by DLS (P<0.05). Kits in DLS group had shorter villus height (P<0.05), higher crypt depth (P<0.05) and shorter vermiform appendix (P<0.05) at the end of the trial. Furthermore, separating kits from the doe had a negative effect on their average daily gain at 3rd wk and 4th wk (P<0.05). Limiting the microbiological contact with the mother during suckling period affected the kits’ intestinal flora and could negatively affect the development of intestinal digestive and immune system and growth performance of kits.This study was funded by Key Science and Technology Programme of Shaanxi Province (No, 2013K02-18).Zhang, Y.; Cui, H.; Sun, D.; Liu, L.; Xu, X. (2018). Effects of doe-litter separation on intestinal bacteria, immune response and morphology of suckling rabbits. World Rabbit Science. 26(1):71-79. https://doi.org/10.4995/wrs.2018.5917SWORD717926

A study on the application of the operating modal analysis method in self-propelled gun development

The basic theory and main features of operating modal analysis method have been elaborated, and then by using this method, the parameters of low-order natural characteristics of some wheeled and tracked self-propelled guns have been obtained. By two examples, the application of the operating modal analysis method for the development of self-propelled gun has been introduced. According to the result of operating modal analysis, for some wheeled self-propelled gun, “beat vibration” between the first-order natural characteristics and firing frequency of the gun has been identified, and further research indicates that the primary cause of the “beat vibration” is that the stiffness of the cradle is too weak which enlarges the vibratory response of the muzzle. With the reinforcement of the cradle, the testing result of firing indicates that the vibratory response of the muzzle is reduced obviously, and that the firing dispersion is much better than before. In order to certificate the accuracy of its dynamic model, for some tracked self-propelled guns, the natural characteristics of the whole gun through a comparison of the operating modal analysis and finite element calculation have been specified, and then according to the results of operating modal analysis, the dynamic model of the gun has been meliorated, and the natural characteristics of the gun by the finite element calculation are consistent with those by the operating modal analysis. This indicates that the model of the gun is correct with the vibratory response of the whole gun under seven running fire simulated, and that the error of vibratory response of the muzzle between firing testing and analog simulation does not exceed 15 %

Activated NK cells kill hepatic stellate cells via p38/PI3K signaling in a TRAIL-involved degranulation manner

NK cells are important in regulating hepatic fibrosis via their cytotoxic killing of hepatic stellate cells (HSCs). NK cells are activated by both cytokines such as IL-12 and IL-18, and innate immune stimuli such as ligation of TLRs. The secretion of IL-18 depends upon activation of the inflammasome, whereas TLRs are stimulated by microbial products. In the case of NK cells, IL-18 acts synergistically with stimulation of TLR3 to cause cell activation and cytotoxic function. In the present study, we activated NK cells to kill HSCs via IL-18 and TLR3 ligand stimulation, and dissected the signaling pathways or molecules critical for such activation or killing. We find that such activation depends on signaling via the p38/PI3K/AKT pathway, and that the activatedNK cells mediate HSC death in a TRAIL-involved mechanism. As liver fibrosis is a major global health problem with no good solution, these results emphasize that the p38/PI3K/AKT pathway in NK cells may be a novel drug target to promote fibrosis regression

The altered intrinsic functional connectivity after acupuncture at shenmen (HT7) in acute sleep deprivation

IntroductionAccumulating evidence has shown that acupuncture could significantly improve the sleep quality and cognitive function of individuals suffering from insufficient sleep. Numerous animal studies have confirmed the effects and mechanisms of acupuncture on acute sleep deprivation (SD). However, the role of acupuncture on individuals after acute SD remains unclear.MethodsIn the current study, we recruited 30 healthy subjects with regular sleep. All subjects received resting-state fMRI scans during the rested wakefulness (RW) state and after 24 h of total SD. The scan after 24 h of total SD included two resting-state fMRI sessions before and after needling at Shenmen (HT7). Both edge-based and large-scale network FCs were calculated.ResultsThe edge-based results showed the suprathreshold edges with abnormal between-network FC involving all paired networks except somatosensory motor network (SMN)-SCN between the SD and RW state, while both decreased and increased between-network FC of edges involving all paired networks except frontoparietal network (FPN)-subcortical network (SCN) between before and after acupuncture at HT7. Compared with the RW state, the large-scale brain network results showed decreased between-network FC in SMN-Default Mode Network (DMN), SMN-FPN, and SMN-ventral attention network (VAN), and increased between-network FC in Dorsal Attention Network (DAN)-VAN, DAN-SMN between the RW state and after 24 h of total SD. After acupuncture at HT7, the large-scale brain network results showed decreased between-network FC in DAN-VAN and increased between-network FC in SMN-VAN.ConclusionAcupuncture could widely modulate extensive brain networks and reverse the specific between-network FC. The altered FC after acupuncture at HT7 may provide new evidence to interpret neuroimaging mechanisms of the acupuncture effect on acute SD