Detection of Ultrasonic Stress Waves in Structures Using 3D Shaped Optic Fiber Based on a Mach–Zehnder Interferometer

This work proposes a 3D shaped optic fiber sensor for ultrasonic stress waves detection based on the principle of a Mach–Zehnder interferometer. This sensor can be used to receive acoustic emission signals in the passive damage detection methods and other types of ultrasonic signals propagating in the active damage detection methods, such as guided wave-based methods. The sensitivity of an ultrasonic fiber sensor based on the Mach–Zehnder interferometer mainly depends on the length of the sensing optical fiber; therefore, the proposed sensor achieves the maximum possible sensitivity by wrapping an optical fiber on a hollow cylinder with a base. The deformation of the optical fiber is produced by the displacement field of guided waves in the hollow cylinder. The sensor was first analyzed using the finite element method, which demonstrated its basic sensing capacity, and the simulation signals have the same characteristics in the frequency domain as the excitation signal. Subsequently, the primary investigations were conducted via a series of experiments. The sensor was used to detect guided wave signals excited by a piezoelectric wafer in an aluminum plate, and subsequently it was tested on a reinforced concrete beam, which produced acoustic emission signals via impact loading and crack extension when it was loaded to failure. The signals obtained from a piezoelectric acoustic emission sensor were used for comparison, and the results indicated that the proposed 3D fiber optic sensor can detect ultrasonic signals in the specific frequency response range

Green Total Factor Productivity Growth and Its Determinants in China’s Industrial Economy

This paper employs directional distance function (DDF) and the global Malmquist–Luenberger (GML) productivity index to measure the green total factor productivity (GTFP) growth of China’s 36 industrial sectors from 2000 to 2014. Based on this, this paper ascertains the determinants of GTFP from the perspectives of institution, technology, and structure, and the determinant factors that affect GTFP are empirically tested by a dynamic panel data (DPD) model. The research shows that, considering energy consumption and environmental undesirable outputs, the industrial GTFP goes backwards by 0.02% per year on average, and the contributions of GTFP to output growth are far from the target value of 50% in all industrial sectors, which indicates that the growth of industrial economy sacrifices resources and environment to a certain degree. In terms of the determinant factors of GTFP, environmental regulation does improve the GTFP, while environmental regulation is difficult to promote GTFP by the route of technological innovation. Compared with technology importation, the driving effect of independent research and development on GTFP is obvious, especially promoting the GTFP of moderately and lightly polluting industries, while the driving effect in heavily polluting industries is poor. Endowment structure and property right structure play a positive role in improving GTFP, but the impacts of capital structure and energy structure on GTFP are poor

N-enrichment induced biodiversity loss can be explained by reductions in competitive intransitivity: Evidence from a decade-long grassland experiment

Recent theoretical and empirical studies demonstrate that intransitive competition is an important mechanism promoting species coexistence and biodiversity maintenance. Few studies, however, have examined how intransitive competition is affected by N enrichment and spatial scale in natural communities. Based on species abundance data from a decade-long field experiment with a control and six levels of N addition rate in semi-arid grassland, we examined the effects of fertilization treatment and spatial scale on competitive intransitivity by using a recently developed Markov chain model approach. Although the relative strength of competitive intransitivity was low (I < 0.3) it was common across all, common and rare species, and over different species pools, with significant competitive intransitivity being detected amongst 60-74 % of the plots in control and nutrient treatment communities. The overall species richness consistently increased with increasing competitive intransitivity among all species and common species; however, the positive effects of intransitivity among rare species on diversity among rare species occurred only at small to moderate spatial scales. For abundance-based species groups, a negative linear relationship between competitive intransitivity and N fertilization rate was common. For trait-based functional groups, the negative effect of high N inputs on competitive intransitivity was found in seven of eight functional groups. For all species groups, the degree of competitive intransitivity generally declined with increasing spatial scale. Our study presents strong evidence that a high degree of competitive intransitivity could promote species coexistence by reducing the negative effect of N fertilization on biodiversity in natural communities. Given that the global N deposition rate is projected to increase in this century, our study sheds new light on the effects and underlying mechanisms of increased N inputs on biodiversity maintenance in semi-arid grasslands

Critical appraisal of studies including the prevalence or incidence of sarcopenia in COPD patients.

Critical appraisal of studies including the prevalence or incidence of sarcopenia in COPD patients.</p

Forest plot of prevalence of sarcopenia in COPD.

Sarcopenia prevalence and its risk factors in chronic obstructive pulmonary disease (COPD) vary partly due to definition criteria. This systematic review aimed to identify the prevalence and risk factors of sarcopenia in COPD patients. This review was registered in PROSPERO (CRD42022310750). Nine electronic databases were searched from inception to September 1st, 2022, and studies related to sarcopenia and COPD were identified. Study quality was assessed using a validated scale matched to study designs, and a meta-analysis was performed to evaluate sarcopenia prevalence. COPD patients with sarcopenia were compared to those without sarcopenia for BMI, smoking, and mMRC. The current meta-analysis included 15 studies, with a total of 7,583 patients. The overall sarcopenia prevalence was 29% [95% CI: 22%–37%], and the OR of sarcopenia in COPD patients was 1.51 (95% CI: 1.19–1.92). The meta-analysis and systematic review showed that mMRC (OR = 2.02, P = 0.04) and age (OR = 1.15, P = 0.004) were significant risk factors for sarcopenia in COPD patients. In contrast, no significant relationship was observed between sarcopenia and smoking and BMI. Nursing researchers should pay more attention to the symptomatic management of COPD and encourage patients to participate in daily activities in the early stages of the disease.</div

Odds ratios for COPD complicated by sarcopenia.

Sarcopenia prevalence and its risk factors in chronic obstructive pulmonary disease (COPD) vary partly due to definition criteria. This systematic review aimed to identify the prevalence and risk factors of sarcopenia in COPD patients. This review was registered in PROSPERO (CRD42022310750). Nine electronic databases were searched from inception to September 1st, 2022, and studies related to sarcopenia and COPD were identified. Study quality was assessed using a validated scale matched to study designs, and a meta-analysis was performed to evaluate sarcopenia prevalence. COPD patients with sarcopenia were compared to those without sarcopenia for BMI, smoking, and mMRC. The current meta-analysis included 15 studies, with a total of 7,583 patients. The overall sarcopenia prevalence was 29% [95% CI: 22%–37%], and the OR of sarcopenia in COPD patients was 1.51 (95% CI: 1.19–1.92). The meta-analysis and systematic review showed that mMRC (OR = 2.02, P = 0.04) and age (OR = 1.15, P = 0.004) were significant risk factors for sarcopenia in COPD patients. In contrast, no significant relationship was observed between sarcopenia and smoking and BMI. Nursing researchers should pay more attention to the symptomatic management of COPD and encourage patients to participate in daily activities in the early stages of the disease.</div

Forest plot of mMRC.

Sarcopenia prevalence and its risk factors in chronic obstructive pulmonary disease (COPD) vary partly due to definition criteria. This systematic review aimed to identify the prevalence and risk factors of sarcopenia in COPD patients. This review was registered in PROSPERO (CRD42022310750). Nine electronic databases were searched from inception to September 1st, 2022, and studies related to sarcopenia and COPD were identified. Study quality was assessed using a validated scale matched to study designs, and a meta-analysis was performed to evaluate sarcopenia prevalence. COPD patients with sarcopenia were compared to those without sarcopenia for BMI, smoking, and mMRC. The current meta-analysis included 15 studies, with a total of 7,583 patients. The overall sarcopenia prevalence was 29% [95% CI: 22%–37%], and the OR of sarcopenia in COPD patients was 1.51 (95% CI: 1.19–1.92). The meta-analysis and systematic review showed that mMRC (OR = 2.02, P = 0.04) and age (OR = 1.15, P = 0.004) were significant risk factors for sarcopenia in COPD patients. In contrast, no significant relationship was observed between sarcopenia and smoking and BMI. Nursing researchers should pay more attention to the symptomatic management of COPD and encourage patients to participate in daily activities in the early stages of the disease.</div

Forest plot of smoking.

Sarcopenia prevalence and its risk factors in chronic obstructive pulmonary disease (COPD) vary partly due to definition criteria. This systematic review aimed to identify the prevalence and risk factors of sarcopenia in COPD patients. This review was registered in PROSPERO (CRD42022310750). Nine electronic databases were searched from inception to September 1st, 2022, and studies related to sarcopenia and COPD were identified. Study quality was assessed using a validated scale matched to study designs, and a meta-analysis was performed to evaluate sarcopenia prevalence. COPD patients with sarcopenia were compared to those without sarcopenia for BMI, smoking, and mMRC. The current meta-analysis included 15 studies, with a total of 7,583 patients. The overall sarcopenia prevalence was 29% [95% CI: 22%–37%], and the OR of sarcopenia in COPD patients was 1.51 (95% CI: 1.19–1.92). The meta-analysis and systematic review showed that mMRC (OR = 2.02, P = 0.04) and age (OR = 1.15, P = 0.004) were significant risk factors for sarcopenia in COPD patients. In contrast, no significant relationship was observed between sarcopenia and smoking and BMI. Nursing researchers should pay more attention to the symptomatic management of COPD and encourage patients to participate in daily activities in the early stages of the disease.</div