5,314 research outputs found

    Diffusive Logistic Equations with Harvesting and Heterogeneity Under Strong Growth Rate

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    We consider the equation −Δu=au−b(x)u2−ch(x) in Ω,u=0 on ∂Ω, where Ω is a smooth bounded domain in RN, b(x) and h(x) are nonnegative functions, and there exists Ω0⊂⊂Ω such that {x:b(x)=0}=Ω¯¯¯0. We investigate the existence of positive solutions of this equation for c large under the strong growth rate assumption a≥λ1(Ω0), where λ1(Ω0) is the first eigenvalue of the −Δ in Ω0 with Dirichlet boundary condition. We show that if h≡0 in Ω∖Ω¯¯¯0, then our equation has a unique positive solution for all c large, provided that a is in a right neighborhood of λ1(Ω0). For this purpose, we prove and utilize some new results on the positive solution set of this equation in the weak growth rate case

    Adaptive feedforward control design for gust loads alleviation and LCO suppression

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    An adaptive feedforward controller is designed for gust loads alleviation and limit cycle oscillations suppression. Two sets of basis functions, based on the finite impulse response and modified finite impulse response approaches, are investigated to design the controller for gust loads alleviation. Limit cycle oscillations suppression is shown by using the modified finite impulse response controller. Worst case gust search is performed by using a nonlinear technique of model reduction to speed up the costs of calculations. Both the “one–minus–cosine” and Von Kármán continuous turbulence gusts of different intensities were generated to examine the performance of controllers. The responses of these two types of gust can be reduced effectively by finite impulse response controller in the whole process, while the modified finite impulse response controller is found to increase the loads during the initial transient response. The above two types of gust induced limit cycle oscillations were used to test the modified finite impulse response controller. Results show that it can suppress limit cycle oscillations to some exten

    Adaptive feedforward control design for gust loads alleviation and LCO suppression

    No full text
    An adaptive feedforward controller is designed for gust loads alleviation and limit cycle oscillations suppression. Two sets of basis functions, based on the finite impulse response and modified finite impulse response approaches, are investigated to design the controller for gust loads alleviation. Limit cycle oscillations suppression is shown by using the modified finite impulse response controller. Worst case gust search is performed by using a nonlinear technique of model reduction to speed up the costs of calculations. Both the “one–minus–cosine” and Von Kármán continuous turbulence gusts of different intensities were generated to examine the performance of controllers. The responses of these two types of gust can be reduced effectively by finite impulse response controller in the whole process, while the modified finite impulse response controller is found to increase the loads during the initial transient response. The above two types of gust induced limit cycle oscillations were used to test the modified finite impulse response controller. Results show that it can suppress limit cycle oscillations to some exten

    Chicken tumours and fishy revenge: Evidence for emotional content bias in the cumulative recall of urban legends

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    This study used urban legends to examine the effects of a cognitive bias for content which evokes higher levels of emotion on cumulative recall. As with previous research into content biases, a linear transmission chain design was used. One-hundred and twenty participants, aged 16–52, were asked to read and then recall urban legends that provoked both high levels and low levels of emotion and were both positively and negatively valenced. The product of this recall was presented to the next participant in a chain of three generations. A significant effect of emotion level on transmission fidelity was found with high emotion legends being recalled with significantly greater accuracy than low emotion legends. The emotional valence of a legend was found not to have any effect on cumulative recall; thus emotional biases in recall go beyond disgust and can incorporate other emotions such as amusement, interest and surprise. This study is the first to examine an emotion bias in cultural transmission as a general phenomenon without focusing on the emotion of disgust

    Evaluating performance of companies by new management tools

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    In this article, we want to design a model for evaluating the performance of companies in the stock market by using TOPSIS and sensitivity analysis. We use financial ratios as criteria in TOPSIS algorithm. In this methodology, first we try to rank companies and then use sensitivity analysis for determining positive and negative points of the company and suggest improving performance of the company

    Evaluating performance of companies by new management tools

    Get PDF
    In this article, we want to design a model for evaluating the performance of companies in the stock market by using TOPSIS and sensitivity analysis. We use financial ratios as criteria in TOPSIS algorithm. In this methodology, first we try to rank companies and then use sensitivity analysis for determining positive and negative points of the company and suggest improving performance of the company

    Evaluating performance of companies by new management tools

    Get PDF
    In this article, we want to design a model for evaluating the performance of companies in the stock market by using TOPSIS and sensitivity analysis. We use financial ratios as criteria in TOPSIS algorithm. In this methodology, first we try to rank companies and then use sensitivity analysis for determining positive and negative points of the company and suggest improving performance of the company

    Status of 25-OH Vitamin D Serum Level among Wheezy Chronic Respiratory Diseases with Airway Obstructive Patterns; Office- Base Study

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     Background: Vitamin D is a homeostasis hormone of the calcium and bone metabolism. It has additional effects in the infections, cardiovascular, immunity, anti- inflammatory, chronic respiratory diseases and small airway disease (SAD). Wheezing is the common clinical feature of small airway obstructive diseases. Prevalent of asthma and chronic obstructive pulmonary disease (COPD) are noticeable among SAD. Propose of the study assessed status of vitamin D level among wheezy chronic respiratory diseases with airway obstructive pattern. Methods: Sample population sequentially enrolled among office base- wheezy patients with chronic obstructive pattern. Vitamin D level was measured by ELISA. Results: We studied on 67 patients. Mean age was 42.9±1.5 SD years, ranged between 17-76 years. Their sex distribution was male 51% and female 49%. Vitamin D deficiency and insufficiency recorded 13% and 40%, respectively. Frequency of lower than set point value of vitamin D among subtypes of SAD was asthma, COPD and other subtypes of SAD, respectively. Conclusion: Outcome of the study disclosed relevant 25-OH vitamin D deficiency and insufficiency among wheezy respiratory diseases with airway obstructive pattern. COPD and asthma small airways were noticeable within population. Deficiency and insufficiency of vitamin D were considerable in female and male, respectively.

    Evaluation of attention bias in morphine and methamphetamine abusers towards emotional scenes during early abstinence: An eye-tracking study

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    Introduction: We hypothesized that inappropriate attention during the period of abstinence in individuals with substance use disorder can result in an inadequate perception of emotion and unsuitable reaction to emotional scenes. The main aim of this research was to evaluate the attentional bias towards emotional images in former substance abusers and compare it to healthy adults. Methods: Paired images of general scenes consisting of pleasant, unpleasant, and neutral images were presented to subjects for 3 s while their attentional bias and eye movements were measured by eye tracking. The participants were 72 male adults consisting of 23 healthy control, 24 morphine former abusers, and 25 methamphetamine former abusers. The former abusers were recruited from a private addiction quitting center and addiction rehabilitation campus. The healthy individuals were selected from general population. Number and duration of first fixation, duration of first gaze, and sustained attention towards emotional scenes were measured as the main variables and the data were analyzed using the repeated measures ANOVA. Results: A significant difference was observed between former morphine abusers and healthy control in terms of number and duration of first fixations and first gaze duration towards pleasant images. Discussion: Individuals with morphine use disorder have more problems with attending to emotional images compared to methamphetamine abusers and healthy people
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