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A bstract Previous studies on high-energy gamma-ray burst neutrinos from IceCube suggest a neutrino speed variation at the Lorentz violation (LV) scale of ~6 . 4 × 10 17 GeV, with opposite velocity variances between neutrinos and antineutrinos. Within a spacetime foam model, inspired by string theory, we develop an approach to describe the suggested neutrino/antineutrino propagation properties with both Lorentz invariance and CPT symmetry breaking. A threshold analysis on the bremsstrahlung of electron-positron pair ( ν → νee + ) for the superluminal (anti)neutrino is performed. We find that, due to the energy violation caused by the quantum foam, such reaction may be restricted to occur at sufficient high energies and could even be kinematically forbidden. Constraints on neutrino LV from vacuum ee + pair emission are naturally avoided. Future experiments are appealed to test further the CPT violation of cosmic neutrinos and/or neutrino superluminality.

A bstract We entertain the constraints that the absence of vacuum Cherenkov radiation of ultrahigh-energy electrons inferred from LHAASO observations of the Crab Nebula can impose on generic models in which Lorentz symmetry of the particle vacuum is violated, as established by some recent studies in Phys. Lett. B 829 (2022) 137034; Phys. Lett. B 835 (2022) 137536; Phys. Rev. D 108 (2023) 063006. We demonstrate in the present paper, that implementing a phenomenological approach to the Lorentz violation, the rates of this vacuum process are substantial such that one is justified in deriving bounds on the violation scales from simple threshold analysis just as these works did. Albeit such results are likely effective then, they do not apply in the same form among scenarios. Specifically, we show that these Cherenkov constraints are naturally evaded in models of space-time foam inspired from (supercritical) string theory, involving D-branes as space-time defects in a brane-world scenario, in which subluminous energy-dependent refractive indices of light have been suggested. We examine here two specific foam situations and find for both cases (though, for different reasons) the potentiality that charged quanta such as electrons do not radiate as they pass through the gravitational vacuum ‘medium’ despite moving faster than photons.

A bstract Neutrinos from the cosmos have proven to be ideal for probing the nature of space-time. Previous studies on high-energy events of IceCube suggested that some of these events might be gamma-ray burst neutrinos, with their speeds varying linearly with their energy, implying also the coexistence of subluminal and superluminal propagation. However, a recent reanalysis of the data, incorporating revised directional information, reveals stronger signals that neutrinos are actually being slowed down compared to previous suggestion of neutrino speed variation. Thus, it is worth discussing its implications for the brane/string inspired framework of space-time foam, which has been used to explain previous observations. We revisit effects on neutrino propagation from specific foam models within the framework, indicating that the implied violation of Lorentz invariance could necessarily cause the neutrino to decelerate. We therefore argue that this sort of model is in agreement with the updated phenomenological indication just mentioned. An extended analysis of the revised IceCube data will further test these observations and stringy quantum gravity.

Biological nitrogen fixation is a key process in the nitrogen cycle and the main source of soil available nitrogen. The number and diversity of nitrogen-fixing bacteria directly reflect the efficiency of soil nitrogen fixation. The alpine wetland on the Qinghai-Tibet Plateau (QTP) is degrading increasingly, with a succession toward alpine meadows. Significant changes in soil physicochemical properties accompany this process. However, it is unclear how does the soil nitrogen-fixing bacteria change during the degradation processes, and what is the relationship between these changes and soil physicochemical properties. In this study, the nifH gene was used as a molecular marker to further investigate the diversity of nitrogen-fixing bacteria at different stages of degradation (none, light, and severe degeneration) in the alpine wetland. The results showed that wetland degradation significantly reduced the diversity, altered the community composition of nitrogen-fixing bacteria, decreased the relative abundance of Proteobacteria, and increased the relative abundance of Actinobacteria. In addition to the dominant phylum, the class, order, family, and genus of nitrogen-fixing bacteria had significant changes in relative abundance. Analysis of Mantel test showed that most soil factors (such as pH, soil water content (SWC), the organic carbon (TOC), total nitrogen (TN), and soil C:P ratio) and abundance had a significant positive correlation. TOC, TN, total phosphorus (TP), soil C:P ratio and Shannon had a significant positive correlation with each other. The RDA ranking further revealed that TOC, SWC, and TN were the main environmental factors influencing the community composition of nitrogen-fixing bacteria. It is found that the degradation of the alpine wetland inhibited the growth of nitrogen-fixing bacteria to a certain extent, leading to the decline of their nitrogen-fixing function.

Autotrophic carbon-fixing bacteria are a major driver of carbon sequestration and elemental cycling in grassland ecosystems. The characteristics of the response of carbon-fixing bacterial communities to nitrogen (N) addition in degraded alpine meadows are unclear. In this study, it was investigated that the effects of N addition in three levels [they are low (LN), middle (MN), and high (HN) with N supplement of 2, 5, and 10 g N⋅m –2 ⋅a –1 , respectively] on soil carbon-fixing bacteria on different slopes in a degraded alpine meadow in the Yellow River on the Qinghai–Tibet Plateau. The results showed that there were significant differences in the abundance of some low abundance genera of carbon-fixing bacteria on the same slope ( P < 0.05), but the differences in the abundance of various phyla and dominant genera were not significant. MN on gentle slopes significantly reduced the Chao1 index and observed species ( P < 0.05), whereas N addition on steep slopes had no significant effect on the diversity. The abundance of the Cyanobacteria phylum and 28 genera of identified carbon-fixing bacteria differed significantly between slopes ( P < 0.05), and observed species of carbon-fixing bacteria were significantly higher on steep slopes than on gentle slopes ( P < 0.05). Factors affecting the carbon-fixing bacteria community structure include slope, N addition, ammoniacal nitrogen (N-NH 4 + ), microbial biomass carbon (MBC), soil water content (SWC), pH, soil C:N ratio, and microbial C:N ratio. Slope, N addition, soil physicochemical properties, microbial biomass, and stoichiometric ratio did not significantly affect the carbon-fixing bacteria diversity. Thus, the effect of exogenous N addition on carbon-fixing bacteria in degraded alpine meadows was dependent on slope conditions, and the response of carbon-fixing bacteria abundance and species number to N addition on gently slope sites was threshold-limited.

Granulomatous mastitis (GM) poses challenges in diagnosis and treatment due to its similarities with other breast diseases like cancer. The comparative study evaluated the efficacy and safety of a vacuum-assisted biopsy device with minimally invasive excisions compared to traditional wide local excisions. The vacuum-assisted biopsy device technique offers benefits such as precise tissue removal, reduced damage to healthy tissue, shorter surgery and recovery times, and lower postoperative complication risks. The study found that the vacuum-assisted biopsy device had comparable efficacy to traditional wide local excision in treating GM with an overall effectiveness rate of 92.9% and a recurrence rate of 9.52%. The vacuum-assisted biopsy device group showed advantages in reduced hospitalization duration (2.83 days vs. 7.52 days), lower costs, and better cosmetic outcomes, with a 100% patient satisfaction rate compared to 80% in the control group. This study fills existing clinical evidence gaps regarding the effectiveness and safety of vacuum-assisted biopsy device in GM treatment. By providing evidence-based guidelines, it aims to assist clinicians in choosing the most appropriate treatment for GM patients, ultimately improving their quality of life and mental well-being. The research contributes valuable insights into GM therapy, potentially revolutionizing treatment approaches and enhancing patient outcomes.

The effect of statins on the risk of dementia and Alzheimer's disease (AD) is unclear. We systematically searched EMBASE, Web of Science, PubMed, CENTRAL and ClinicalTrail.gov for cohort studies comparing incidence of new-onset dementia and AD between statin users and non-users. We applied the DerSimonian-Laird random effects method to pool hazard ratio (HR) with 95% confidence intervals (CI). We included forty-two studies comprising 6,325,740 patients. Thirty-five cohort studies involving 6,306,043 participants were pooled and indicated that statin use was associated with a reduced risk of dementia (HR: 0.79, 95% CI: 0.71-0.88). Similarly, an analysis of 19 studies comprising 1,237,341 participants demonstrated a 29% decrease in the risk of AD among statin users (HR: 0.71, 95% CI: 0.60-0.85). In sensitivity analyses, diagnostic criteria for dementia/AD significantly affected the combined risk estimates. In subgroup analyses, compared to studies enrolling participants with a mean/median age over 70 years, those younger than 70 years exhibited greater efficacy of statins in preventing dementia (HR: 0.67, 95% CI: 0.56-0.81 vs HR: 0.86, 95% CI: 0.78-0.95; P = 0.02) and AD (HR: 0.47, 95% CI: 0.44-0.50 vs. HR: 0.81, 95% CI: 0.71-0.92; P < 0.01). Due to significant heterogeneity in the definitions of statin dosage and exposure duration, pooling the results was abandoned and most studies suggested that higher dosages and longer exposure duration of statins further reduce the risk of dementia and AD. Statin use is associated with a reduced incidence of dementia and AD, which might be modified by ages.

Understanding the impact of deep groundwater depth on vegetation communities and soil in sand dunes with different underground water tables is essential for ecological restoration and the conservation of groundwater. Furthermore, this understanding is critical for determining the threshold value of groundwater depth that ensures the survival of vegetation. This paper was conducted in a semi-arid region in eastern China, and the effects of deep groundwater depth (6.25 m, 10.61 m, and 15.26 m) on vegetation communities and soil properties (0-200 cm) across three dune types (mobile, semi-fixed, and fixed dunes) were evaluated in a sand ecosystem in the Horqin Sandy Land. For vegetation community, variations in the same species are more significant at different groundwater depths. For soil properties, groundwater depth negatively influences soil moisture, total carbon, total nitrogen, available nitrogen, available phosphorus concentrations, and soil pH. Besides, groundwater depth also significantly affected organic carbon and available potassium concentrations. In addition, herb species were mainly distributed in areas with lower groundwater depth, yet arbor and shrub species were sparsely distributed in places with deeper groundwater depth. As arbor and shrub species are key drivers of ecosystem sustainability, the adaptation of these dominant species to increasing groundwater depth may alleviate the negative effects of increasing groundwater depth; however, restrictions on this adaptation were exceeded at deeper groundwater depth.

To analyze the predictive value of hyperglycemia on the extrapancreatic infection (EPI) and infected pancreatic necrosis (IPN) of severe patients with acute pancreatitis (AP). We enrolled 234 patients with acute pancreatitis admitted to the intensive care unit (ICU) of the Second Affiliated Hospital of Nanchang University from July 2017 to July 2022 for a retrospective cohort study. We collected maximum blood glucose values three times after admission to the ICU within 120 h (Glu1: 0–24 h, Glu2: 24–48 h, Glu3: 48–120 h), the levels of leucocyte, blood urea nitrogen (BUN), C-reactive protein (CRP), procalcitonin (PCT), and albumin within 24 h after admission to the ICU, and the BISAP and SIRS scores of all patients within 24 h. EPI was taken as the primary outcome indicator and IPN as the secondary outcome indicator. The accuracy of blood glucose values in predicting acute pancreatitis infection was measured by the area under the curve (AUC). A total of 56 patients appeared EPI. Univariate analysis showed that Glu3 was associated with IPN in critically ill patients with AP. Multivariate logistic regression analysis showed that Glu2, Glu3, and SIRS > 48 h were associated with EPI in critically ill patients with AP. The AUCs of Glu2 and Glu3 to predict EPI were 0.805(95%CI: 0.717–0.892) and 0.782(95%CI: 0.685–0.878), respectively, and the cutoff values were 12.60 mmol/L and 14.75 mmol/L, respectively. The AUC of Glu2 combined with Glu3 to predict EPI was 0.812(0.725–0.899). The maximum blood glucose on Day2-5 after admission to the ICU can predict infection in critically ill patients with AP. There are differences in etiology while glucose predicting infection. Patients with hypertriglyceridemia AP need to intervene blood glucose levels more actively and earlier, and control it more strictly.

In the actual working environment, most equipment models present nonlinear characteristics. For nonlinear system filtering, filtering methods such as the Extended Kalman Filter (EKF), Unscented Kalman Filter (UKF), and Cubature Kalman Filter (CKF) have been developed successively, all of which show good results. However, in the process of nonlinear system filtering, the performance of EKF decreases with an increase in the truncation error and even diverges. With improvement of the system dimension, the sampling points of UKF are relatively few and unrepresentative. In this paper, a novel high-order extended Unscented Kalman Filter (HUKF) based on an Unscented Kalman Filter is designed using the higher-order statistical properties of the approximate error. In addition, a method for calculating the approximate error of the multi-level approximation of the original function under the condition that the measurement is not rank-satisfied is proposed. The effectiveness of the filter is verified using digital simulation experiments.