Robust tracking control for uncertain MIMO nonlinear systems with input saturation using RWNNDO

In this paper, the robust tracking control scheme is proposed for a class of uncertain multi-input and multi-output (MIMO) nonlinear systems with input saturation and unknown external disturbance based on the recurrent wavelet neural network disturbance observer (RWNNDO) and the backstepping technique. And then, the developed robust tracking control scheme is applied to an unmanned aerial vehicle (UAV) system. To handle the input saturation, a hyperbolic tangent function and a Nussbaum function are employed, and the dynamic surface method is applied to solve the problem of “explosion of complexity” in backstepping control. It is proved that the proposed control scheme can guarantee that all signals of the closed-loop system are bounded through the Lyapunov analysis. Simulation results are presented to demonstrate the effectiveness of the proposed control scheme for uncertain MIMO nonlinear systems

Errors in medical imaging and radiography practice : a systematic review

Background: Errors in health care can harm patients and undermine public trust, yet many are preventable. In medical imaging and radiography, errors can cause increased radiation dose, misdiagnosis, and clinical mismanagement. Aim: The purpose of this review was to identify the type and prevalence of errors directly associated with radiography practice and the imaging cycle, with a view to developing recommendations to reduce common errors. Method: A systematic review was undertaken of current literature obtained through the Ovid Medline and PubMed databases. A total of 41 useable articles were analysed into a priori categories of the medical imaging cycle: preprocedural, procedural, and postprocedural. Findings: This review found that errors may occur during any phase of the cycle and that communication breakdown, especially during handover periods, was the main contributing factor to errors. Although the importance of incident reporting is well recognised, feedback to users is often limited. Conclusions: A systematic approach to radiographic practice may assist in reducing communication-related errors. Future research is required to determine how extending radiographers’ roles or using electronic ordering systems could also help to reduce errors

State estimation for coupled output discrete-time complex network with stochastic measurements and different inner coupling matrices

A state estimation problem is studied for a class of coupled outputs discrete-time networks with stochastic measurements, i.e., the measurements are missing and disturbed with stochastic noise. The considered networks are coupled with outputs rather than states, are coupled with different inner coupling matrices rather than identical inner ones. By using Lyapunov stability theory combined with stochastic analysis, a novel state estimation scheme is proposed to estimate the states of discrete-time complex networks through the available output measurements, where the measurements are stochastic missing and are disturbed with Brownian motions which are caused by data transmission among nodes due to communication unreliability. State estimation conditions are derived in terms of linear matrix inequalities (LMIs). A numerical example is provided to demonstrate the validity of the proposed scheme

A Multi-agent Simulation Paradigm of Customer Retention Management

Customer retention is one of the most important topics in customer relationship management research. To date, customer retention studies are mainly carried out on the macro or firm level instead of the individual customer level. This study develops a model of customer retention management from the individual customer perspective. This model introduces multiple agents and considers the interactions among these individual agents (firms and customers). Specifically, to establish this multi-agent simulation paradigm, the paper uses customer trigger threshold, customer competence increment and stimulus-behavior mechanism to model micro customer behaviors, and then relates the customer behaviors with the customer retention/acquisition shares of the firms

A synthetic lethal screen identifies the Vitamin D receptor as a novel gemcitabine sensitizer in pancreatic cancer cells

<div><p>Overcoming chemoresistance of pancreatic cancer (PCa) cells should significantly extend patient survival. The current treatment modalities rely on a variety of DNA damaging agents including gemcitabine, FOLFIRINOX, and Abraxane that activate cell cycle checkpoints, which allows cells to survive these drug treaments. Indeed, these treatment regimens have only extended patient survival by a few months. The complex microenvironment of PCa tumors has been shown to complicate drug delivery thus decreasing the sensitivity of PCa tumors to chemotherapy. In this study, a genome-wide siRNA library was used to conduct a synthetic lethal screen of Panc1 cells that was treated with gemcitabine. A sublethal dose (50 nM) of the drug was used to model situations of limiting drug availability to PCa tumors in vivo. Twenty-seven validated sensitizer genes were identified from the screen including the Vitamin D receptor (VDR). Gemcitabine sensitivity was shown to be VDR dependent in multiple PCa cell lines in clonogenic survival assays. Sensitization was not achieved through checkpoint override but rather through disrupting DNA repair. VDR knockdown disrupted the cells’ ability to form phospho-γH2AX and Rad51 foci in response to gemcitabine treatment. Disruption of Rad51 foci formation, which compromises homologous recombination, was consistent with increased sensitivity of PCa cells to the PARP inhibitor Rucaparib. Thus inhibition of VDR in PCa cells provides a new way to enhance the efficacy of genotoxic drugs.</p></div

The prevalence and associated factors of prenatal depression and anxiety in twin pregnancy: a cross-sectional study in Chongqing, China

Background Pregnant women expecting twins are more likely to experience stress, which can lead to anxiety and depression. Our aim was to investigate the prevalence of prenatal anxiety and depressive symptoms in women with twin pregnancies and the associated factors. Methods In a cross-sectional survey, 210 women with twin pregnancies who satisfied the inclusion and exclusion criteria in two tertiary centers in Southwestern China were asked to complete a basic information form, the Self-Rating Anxiety Scale (SAS) and the Self-Rating Depression Scale (SDS). To compare statistics with normal distribution in distinct characteristic groups, a paired t-test, and one-way ANOVA were utilized. Binary logistic step regression was used to analyze the associated factors of antenatal anxiety and depressive symptoms. Results The 210 women with twin pregnancies (age = 30.8 ± 4.2 years) were between 7 and 37 gestational weeks (29.2 ± 1.2 weeks), were typically well-educated (72.4% had a post-high-school degree), and reasonably affluent (88.1% were above the low-income cutoff). Among them, 34.8% had symptoms associated with clinical levels of anxiety, and 37.1% had symptoms indicating possible depression. The prevalence of co-morbid anxiety and depressive symptoms was 24.3%. Binary stepwise logistic regression analysis showed that previous health status and sleep disturbance during pregnancy were the associated factors of anxiety symptoms in women with twin pregnancies (P  Conclusion About one-third of women with twin pregnancies had symptoms of anxiety or depression; these were most strongly predicted by some modifiable factors, suggesting that early preventive mind-body interventions may be a promising strategy to protect against mental health issues for women with twin pregnancies.</p

Fool Me Once, Shame on You; Fool Me Twice, Shame on Me: The Long-Term Impact of Arthur Andersen's Demise on Partners' Audit Quality*

Although recent evidence suggests that individual audit partners explain a substantial portion of the variation in audit quality proxies, much less is known about what determines an audit partner's quality. Psychology and behavioral economics theories hold that an individual's experiences can have enduring impacts on subsequent behavior. We examine whether auditors' direct exposure to Arthur Andersen's collapse has a long-term impact on the quality of their audits. Our evidence implies that audit partners who directly experienced Andersen's demise impose stricter monitoring evident in their clients exhibiting a lower propensity for misstatements and small profits, and paying higher audit fees. Importantly, these findings reconcile with research in finance and economics implying that firsthand experiences matter more to subsequent behavior than general economic conditions or secondhand or thirdhand experiences. Collectively, the results shed light on one facet of how partners' audit quality evolves over time. Our findings suggest that major failures associated with the audit firm in which an auditor works can ultimately result in these affected individuals later delivering higher audit quality, which should benefit audit committees in partner selection decisions and audit firms in designing partner assignment policies

Screening and characterization of phenolic compounds by LC-ESI-QTOF-MS/MS and their antioxidant potentials in papaya fruit and their by-products activities

Papaya (Carica papaya L.) is one of the most commonly planted and consumed fruits in the world, especially in tropical and subtropical areas. In recent years, due to the diverse range of nutritional value and medicinal properties of bioactive substances possessed in papaya, papaya fruit and their by-products have gained more attention. The present study aimed to characterize the different parts (pulp, peel, and seed) of two varieties of papaya (yellow- and red-fleshed) at different stages of ripeness (unripe and ripe) for their phenolic compounds using liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS). The phenolic content and antioxidant activity were detected through several assays. Yellow-fleshed unripe papaya seed showed the highest total phenolic content (TPC) (4.73 mg GAE/g). Red-fleshed ripe papaya peel exhibited the highest level of total tannin content (TTC) with 1.98 mg CE/g, while red-fleshed unripe peel exhibited the highest total flavonoid content (TFC) with 2.78 ± 0.04 mg QE/g. In terms of antioxidant potential, yellow-fleshed unripe papaya peels had the highest radical scavenging activities for the DPPH, ABTS, and TAC tests. LC-ESI-QTOF-MS/MS experiment successfully tentatively identified 118 phenolic compounds in total, including phenolic acids (35), flavonoids (61), stilbenes (3), lignans (7) and other polyphenols (12) in all papaya samples. Analyses indicate that the three different parts of the papaya fruit are potential sources of phenolic compounds, particularly the peel. The results of this study provide practical data for the potential application of papaya fruit as a functional food ingredient in the food, pharmaceutical and medicinal industries

Optimization and decision making of guide vane closing law for pumped storage hydropower system to improve adaptability under complex conditions

The pumped storage hydropower system (PSHS) is considered a high-quality peaking and frequency regulation energy source due to its operational flexibility and fast response. However, its frequent regulation leads to complex operating conditions with potential harm to the stability of the system. This paper focuses on analyzing and improving the adaptability of guide vane closing law under complex conditions. This is obtained by proposing a refined numerical model of PSHS considering non-linear factors and analyzing the effects of the guide vane closing law and initial operating conditions on the load rejection. The results revealed that a suitable two-stage guide vane closing law effectively reduces the risk of load rejection. In addition, when the initial load of two units is different, it is beneficial to improve the load rejection characteristics when the unit with the smaller load rejects the load first. Finally, three groups of parameters for the optimal guide vane closing law (the Pareto solution sets) are obtained by multi-objective sparrow search algorithm (MOSSA) under the rated, maximum water head, and maximum rotational speed conditions. The obtained Pareto solution and the Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS) are used for scoring the solutions and obtain an optimal suitable for complex operating conditions. The water head and rotational speed are reduced by an average of 7.76 % and 3.74 % for the different operating conditions compared to the model validation results, respectively. These results provide a theoretical basis for the selection of the optimal guide vane closing laws and improve the safety during load rejection under complex practical operating conditions

Transcriptome profiling of lentil (Lens culinaris) through the first 24 hours of Ascochyta lentis infection reveals key defence response genes

Background: Ascochyta blight, caused by the fungus Ascochyta lentis, is one of the most destructive lentil diseases worldwide, resulting in over $16 million AUD annual loss in Australia alone. The use of resistant cultivars is currently considered the most effective and environmentally sustainable strategy to control this disease. However, little is known about the genes and molecular mechanisms underlying lentil resistance against A. lentis. Results: To uncover the genetic basis of lentil resistance to A. lentis, differentially expressed genes were profiled in lentil plants during the early stages of A. lentis infection. The resistant 'ILL7537' and susceptible 'ILL6002' lentil genotypes were examined at 2, 6, and 24 h post inoculation utilising high throughput RNA-Sequencing. Genotype and time-dependent differential expression analysis identified genes which play key roles in several functions of the defence response: fungal elicitors recognition and early signalling; structural response; biochemical response; transcription regulators; hypersensitive reaction and cell death; and systemic acquired resistance. Overall, the resistant genotype displayed an earlier and faster detection and signalling response to the A. lentis infection and demonstrated higher expression levels of structural defence-related genes. Conclusions: This study presents a first-time defence-related transcriptome of lentil to A. lentis, including a comprehensive characterisation of the molecular mechanism through which defence against A. lentis is induced in the resistant lentil genotype. © 2018 The Author(s)