Nonparametric maximum likelihood approach to multiple change-point problems

In multiple change-point problems, different data segments often follow different distributions, for which the changes may occur in the mean, scale or the entire distribution from one segment to another. Without the need to know the number of change-points in advance, we propose a nonparametric maximum likelihood approach to detecting multiple change-points. Our method does not impose any parametric assumption on the underlying distributions of the data sequence, which is thus suitable for detection of any changes in the distributions. The number of change-points is determined by the Bayesian information criterion and the locations of the change-points can be estimated via the dynamic programming algorithm and the use of the intrinsic order structure of the likelihood function. Under some mild conditions, we show that the new method provides consistent estimation with an optimal rate. We also suggest a prescreening procedure to exclude most of the irrelevant points prior to the implementation of the nonparametric likelihood method. Simulation studies show that the proposed method has satisfactory performance of identifying multiple change-points in terms of estimation accuracy and computation time.Comment: Published in at http://dx.doi.org/10.1214/14-AOS1210 the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org

Quantum Correlation Sharing: A Review On Recent Progress From Nonlocality To Other Non-Classical Correlations

This review offers a comprehensive exploration and synthesis of recent advancements in the domain of quantum correlation sharing facilitated through sequential measurements. We initiate our inquiry by delving into the interpretation of the joint probability, laying the foundation for an examination of quantum correlations within the context of specific measurement methods. The subsequent section meticulously explores nonlocal sharing under diverse measurement strategies and scenarios, with a specific focus on investigating the impact of these strategies on the dissemination of quantum nonlocality. Key perspectives such as "asymmetry" and "weak value" are scrutinized through detailed analyses across various scenarios, allowing us to evaluate the potential of nonlocality sharing. We also provide a retrospective overview of experimental endeavors associated with this phenomenon. The third part of our exploration presents research findings on steering sharing, offering clarity on the feasibility of steering sharing and summarizing the distinctive properties of quantum steering sharing in different scenarios. Continuing our journey, the fourth section delves into discussions on the sharing of diverse quantum correlations, encompassing network nonlocality, quantum entanglement, and quantum contextuality. Moving forward, the fifth section conducts a comprehensive review of the progress in the application of quantum correlation sharing, specifically based on sequential measurement strategies. Applications such as quantum random access coding, random number generation, and self-testing tasks are highlighted. Finally, we discuss and list some of the key unresolved issues in this research field, and conclude the entire article

Temporal and spatial evolution law of microseisms and induced impact mechanism in complex spatial structure area of steep and extremely thick coal seam

The occurrence of coal mine rock burst disasters is closely related to the spatial structure, especially in the complex spatial structure area. It is of great significance to master the law of coal and rock catastrophe and reveal its mechanism in the complex spatial structure area of coal seam mining for the prevention and control of rock burst. Taking the Wudong Coal Mine as the research background, using numerical simulation, micro-seismic monitoring, theoretical analysis and other methods, the abnormal size effect of rock pillar stress is studied, the temporal and spatial evolution law of microseisms in the complex spatial structure area is analyzed, the mechanism of rock burst under the complex spatial structure is revealed, and the impact risk in the different areas of coal mining is evaluated. The research results show that: ① The steeply inclined rock pillar with narrower thickness and higher exposed height has stronger prying effect, and the abnormal stress of rock thickness variation forms five divisions. ② The area with narrower rock pillar thickness has more micro-seismic frequency, higher energy, stronger spatio-temporal activity and higher dispersion. The high stress region, the stress gradient region and the stress plateau region show the micro-seismic response characteristics of “low frequency-high energy”, “high frequency-high energy” and “low frequency-low energy” in turn. ③ The micro-seismic events in special spatial structure area are clustered and the energy level increases, and the temporal and spatial activity and dispersion increase sharply. This feature is more obvious especially at the edge of the structure, the energy accumulation and release rate increases, and the probability and intensity of rock burst are higher. The micro-seismic activity of special spatial structures located in the narrower area of rock pillars is more acute. ④ The narrower the thickness of rock pillar (the greater the height of coal pillar), the faster the growth rate of bending moment and energy in the depth of rock pillar, and the higher the impact risk. According to the strength effect of structural plane, it is inferred that the fault zone has slip and dislocation, and fault zone is the dominant area for energy accumulation and release. It is revealed that the mechanism of rock burst is the joint action of high static load and low critical load. The impact risk in the different areas of coal mining is evaluated based on stress concentration characteristics

Precursory characteristics and disaster prevention of rock burst in roadway excavation in steeply inclined extra-thick coal seam

With the gradual coal mining of deep rock burst mine, the impact accompanying roadway excavation becomes more and more intense. Aiming at the problem of effective prevention and control of rock burst in roadway excavation, taking the steep seam mine in the Wudong Coal Mine as an example, the temporal and spatial precursor characteristics of rock burst in roadway excavation were analyzed by microseismic monitoring. Combined with the numerical simulation analysis of stress and energy changes in roadway excavation, the mechanism of rock burst in roadway excavation was revealed, and the prevention and control strategy of rock burst in steeply inclined extra-thick coal seam roadway was put forward, which was verified by field engineering practice. The results show that the total energy of microseisms is extremely low for 2−5 days or there is an energy latency of at least 4 days before the rock burst occurs due to roadway excavation in steeply inclined extra-thick coal seam. Within 5 days before rock burst occurs, there is a high-frequency fluctuation period of maximum energy ratio for more than 3 days. There is an obvious lack of earthquake before the rock burst occurs, and the occurrence position is concentrated in the range of minimum value of microseismic energy near the heading face, or in the range of minimum value of microseismic frequency near the extreme value of microseismic energy, and the rock burst event is located in the area with high impact deformation energy index. The hard overburden structure of horizontal sublevel fully mechanized caving mining in steeply inclined extra-thick coal seam is not easy to break, which makes the stress concentration on both sides of upper horizontal goaf exist in roadway excavation. The stress between the front of the heading face and the bottom of the roadway squeezed by the roof and floor strata is concentrated and the energy accumulation is remarkable. With the increase of the heading depth of the roadway, the stress concentration and energy accumulation are further enhanced, which is easy to induce dynamic disasters such as rock burst. The prevention and control strategies of rock burst was established through comprehensive analysis, which consist of face blasting pressure relief, roadway drilling pressure relief and reinforcement support, and scaffolding in complex areas. Combined with the temporal and spatial precursory anomalies of rock burst, it provides an opportunity to strengthen the unloading pressure in time. Through the pressure relief of working face and roadway, the accumulated microseismic energy of more than 1×105 J per day did not occur during the excavation. After the support was optimized and the complex area was protected, the daily average microseismic energy of roadway excavation decreased to 2.2 kJ, and the proportion of microseismic events above 1 kJ decreased, and the overall section of roadway was flat

A novel probiotic formula, BLLL, ameliorates chronic stress-induced depression-like behaviors in mice by reducing neuroinflammation and increasing neurotrophic factors

Introduction: Probiotics have been recognized for their various biological activities, including antioxidant and anti-inflammatory properties. This study investigates the therapeutic effect of a novel probiotic formula, BLLL, consisting of Bifidobacterium breve, Lactobacillus plantarum, Lactobacillus paracasei, and Lactobacillus helveticus, on chronic stress-induced depression-like behaviors in mice.Methods: The BLLL formula or phosphate-buffered saline (PBS) was given orally at a dose of 2, 4, or 8 × 1010 CFU/kg once daily for 10 days in mice treated with chronic unpredictable stress (CUS) treated or vehicle. Depression-like behaviors were assessed using the sucrose preference test (SPT), the forced swimming test (FST), and the tail suspension test (TST). The mRNA and/or protein expression of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), IL-4, IL-10, and chitinase-3-like protein 3 (CHI3L1, also known as Ym-1), as well as the concentration of nitrite, malondialdehyde (MDA), glutathione (GSH), and brain-derived neurotrophic factor (BDNF) in the hippocampus and medial prefrontal cortex were examined.Results: The BLLL formula treatment at a dose of 8 × 1010 CFU/kg, but not at a dose of 2 or 4 × 1010 CFU/kg, improved CUS-induced depression-like behaviors in mice, as shown by the decrease in immobility time in the TST and FST and the increase in sucrose intake in the SPT. Further analysis revealed that BLLL treatment suppressed the CUS-induced increase in IL-1β, IL-6, and TNF-α mRNA and protein levels, as well as the CUS-induced decrease in IL-4, IL-10, and Ym-1 mRNA and/or protein levels in the hippocampus and medial prefrontal cortex. In addition, treatment with the BLLL formula countered the CUS-induced increase in nitrite and MDA levels and the CUS-induced decrease in GSH content and BDNF concentration in the hippocampus and medial prefrontal cortex.Conclusion: These results demonstrate that the novel probiotic formula BLLL ameliorates chronic stress-induced depression-like behavior in mice by suppressing neuroinflammation and oxido-nitrosative stress in the brain