An Ameliorated Improvement Factor Model for Imperfect Maintenance and Its Goodness of Fit

<p>Maintenance actions can be classified, according to their efficiency, into three categories: perfect maintenance, imperfect maintenance, and minimal maintenance. To date, the literature on imperfect maintenance is voluminous, and many models have been developed to treat imperfect maintenance. Yet, there are two important problems in the community of maintenance that still remain wide open: how to give practical grounds for an imperfect-maintenance model, and how to test the fit of a real dataset to an imperfect-maintenance model. Motivated by these two pending problems, this work develops an imperfect-maintenance model by taking a physically meaningful approach. For the practical implementation of the developed model, we advance two methods, called QMI method and spacing-likelihood algorithm, to estimate involved unknown parameters. The two methods complete each other and are widely applicable. To offer a practical guide for testing fit to an imperfect-maintenance model, this work promotes a bootstrapping approach to approximating the distribution of a test statistic. The attractions and dilemmas of QMI method and spacing-likelihood algorithm are revealed via simulated data. The utility of the developed imperfect-maintenance model is evidenced via a real dataset. This article has a supplementary material online.</p

DataSheet_1_The effects of behavioral intervention on anthropometric, clinical, and biochemical parameters in patients with polycystic ovary syndrome: a systematic review and meta-analysis.doc

ObjectiveTo evaluate the effects of behavioral intervention for polycystic ovary syndrome (PCOS).MethodsElectronic databases were searched, including Pubmed, Medline, EMBASE, and the Cochrane Central Register of Controlled Trials from inception to 1 April 2023. Inclusion criteria for this study required a diagnosis of PCOS. Interventions of interest included behavioral intervention and routine treatment compared with routine treatment. The studies included in the analysis were designed as randomized controlled trials (RCTs). We conducted meta-analyses following the recommended guidelines. The data was analyzed using either the random effects model or fixed effects model. The results of the studies were expressed as either mean differences (MD) or standardized mean differences (SMD) along with their corresponding 95% confidence intervals (CIs).ResultsEight RCTs were identified, including data from 744 patients (415 in the intervention group and 329 in the control group). The results indicate an improvement in the effectiveness of behavioral interventions for weight loss (MD: -1.07; 95% CI: -2.1 to 0.03; I2 = 0%; P=0.04), body mass index (BMI) (MD: -1.12; 95% CI: -1.92 to -0.33; I2 = 73%; P=0.006), waist circumference (MD: -3.97; 95% CI: -5.64 to -2.29; I2 = 0%; P2 = 0%; P=0.008), depression (SMD: -1.12; 95% CI: -2.35 to -0.07; I2 = 92%; P=0.04), and triglycerides (MD: -0.16; 95% CI: -0.27 to -0.05; I2 = 27%; P=0.004). However, there were no significant differences in menstrual cycles, hirsutism, emotions, and infertility. The study also found that behavioral interventions had no significant effect on systolic and diastolic blood pressure, high-density lipoprotein, low-density lipoprotein, homeostasis model assessment of insulin resistance, testosterone, total cholesterol, fasting glucose, fasting insulin, hemoglobin A1C, and sex hormone binding globulin.ConclusionBehavioral intervention supplementation contributes to weight loss, reduction in BMI and waist circumference, and improvement in depression among patients with PCOS. However, no significant improvement was observed in the biochemical index and quality of life. The long-term effects of behavioral intervention for PCOS remain unclear due to limitations in the quality of the studies involved and the short duration of treatment.Systematic Review Registrationhttps://www.crd.york.ac.uk/PROSPERO, identifier CRD42023442875.</p

Infrared Spectroscopic Investigation of the Acidic CH Bonds in Cationic <i>n</i>‑Alkanes: Pentane, Hexane, and Heptane

Radical cations of <i>n</i>-alkanes (pentane, hexane, and heptane) in the gas phase are investigated by infrared predissociation spectroscopy with the argon or nitrogen tagging. All-trans and gauche-involving conformers are identified for these cations by comparisons of observed infrared spectra and vibrational simulations. Intense CH stretch bands are observed in the frequency region lower than the normal alkyl CH stretch frequency. These low frequencies and high intensities of the CH stretch bands are caused by the CH bond weakening and the enhanced positive charge of the hydrogen atoms through the delocalization of the σ electron in the CH bonds. These effects of the delocalization of the σ electron result in the enhanced acidity of the CH bonds. The conformation as well as alkyl chain length dependence of the acidity of the CH bonds is demonstrated by the CH stretch frequency shift trend

Single-Photon Ionization Induced New Covalent Bond Formation in Acrylonitrile(AN)–Pyrrole(Py) Clusters

The formation of nitrogen-containing organic compounds is crucial for understanding chemical evolution and the origin of life in the interstellar medium (ISM). In this study, we explore whether acrylonitrile (AN) and pyrrole (Py) can form new nitrogen-containing compounds after single-photon ionization in their gaseous clusters by vacuum ultraviolet (VUV)-infrared (IR) spectroscopy and theoretical calculations. The results show that a strong linear H-bond is formed in neutral AN-Py, while cyclic or bicyclic H-bonded networks are formed in the neutral AN-Py2 cluster. It is found that the structure containing a new C–C covalent bond between two moieties in (AN-Py)+ is formed besides the formation of H-bonded structures after AN-Py is ionized by VUV light. In (AN-Py2)+ cluster cations, new C–C or C–N covalent bonds tend to be formed between two Py, with (Py)2+ as the core in the cluster. The results reveal that new covalent bonds are more likely to be formed between two Py species when AN and Py are present in the cationic clusters. These results provide spectroscopic evidence of the formation of new nitrogen-containing organic compounds from AN and Py induced by VUV, which are helpful for our understanding of the formation of diverse prebiotic molecules in interstellar space

Sensitivity of the function against <i>X</i> on the interval of (2, 5).

<p>Sensitivity of the function against <i>X</i> on the interval of (2, 5).</p

Actual test risks under exponential distribution.

<p>Actual test risks under exponential distribution.</p

Pre-specified parameters for Weibull numerical example.

<p>Pre-specified parameters for Weibull numerical example.</p

Pre-specified parameters for exponential numerical example.

<p>Pre-specified parameters for exponential numerical example.</p

Simulated data set for exponential numerical example.

<p>Simulated data set for exponential numerical example.</p

Coverage rate of simulations results as an estimated lower limit of system reliability subject to exponential component lifetime distribution.

<p>Coverage rate of simulations results as an estimated lower limit of system reliability subject to exponential component lifetime distribution.</p