2,300 research outputs found

    Implication of Production Tax Credit on Economic Dispatch for Electricity Merchants with Storage and Wind Farms

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    The production tax credit (PTC) promotes wind energy development, reduces power generation costs, and can affect merchants\u27 joint economic dispatch, particularly for electricity merchants with both energy storage and wind farms. Two common PTC policies are studied – in the first policy, a wind farm receives PTC by selling wind generation to the market and its storage can be used to store energy from the wind generation and energy purchased from the grid but the energy released from the storage cannot receive PTC; in the second policy, the energy released from the storage can also qualify for PTC but purchasing energy from the grid is not allowed. We then employ dynamic programming to study merchants\u27 optimal decision-making while considering PTC and the physical characteristics of storage systems. We analytically show that the state of charge (SOC) range can be segmented into different regions by SOC reference points under two PTC policies. The merchant\u27s optimal action can be conveniently and uniquely determined based on the region within which the current SOC falls. Moreover, this study illustrates that PTC could substantially alter the optimal scheduling policy structures by affecting reference points and their relationships. The results showed that the frequencies for charging and discharging storage decisions decreased with an increase in PTC subsidy. Last, we confirm that, although the first policy allows merchants to buy electricity from the market, the second policy can bring more profits when the PTC is large at the current PTC rates. The findings can provide multistage decision-making guidance to electricity merchants in the wholesale power market

    miR-638 is a new biomarker for outcome prediction of non-small cell lung cancer patients receiving chemotherapy.

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    MicroRNAs (miRNAs), a class of small non-coding RNAs, mediate gene expression by either cleaving target mRNAs or inhibiting their translation. They have key roles in the tumorigenesis of several cancers, including non-small cell lung cancer (NSCLC). The aim of this study was to investigate the clinical significance of miR-638 in the evaluation of NSCLC patient prognosis in response to chemotherapy. First, we detected miR-638 expression levels in vitro in the culture supernatants of the NSCLC cell line SPC-A1 treated with cisplatin, as well as the apoptosis rates of SPC-A1. Second, serum miR-638 expression levels were detected in vivo by using nude mice xenograft models bearing SPC-A1 with and without cisplatin treatment. In the clinic, the serum miR-638 levels of 200 cases of NSCLC patients before and after chemotherapy were determined by quantitative real-time PCR, and the associations of clinicopathological features with miR-638 expression patterns after chemotherapy were analyzed. Our data helped in demonstrating that cisplatin induced apoptosis of the SPC-A1 cells in a dose- and time-dependent manner accompanied by increased miR-638 expression levels in the culture supernatants. In vivo data further revealed that cisplatin induced miR-638 upregulation in the serum derived from mice xenograft models, and in NSCLC patient sera, miR-638 expression patterns after chemotherapy significantly correlated with lymph node metastasis. Moreover, survival analyses revealed that patients who had increased miR-638 levels after chemotherapy showed significantly longer survival time than those who had decreased miR-638 levels. Our findings suggest that serum miR-638 levels are associated with the survival of NSCLC patients and may be considered a potential independent predictor for NSCLC prognosis

    The effects of online game addiction on reduced academic achievement motivation among Chinese college students: the mediating role of learning engagement

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    IntroductionThe present study aimed to examine the effects of online game addiction on reduced academic achievement motivation, and the mediating role of learning engagement among Chinese college students to investigate the relationships between the three variables.MethodsThe study used convenience sampling to recruit Chinese university students to participate voluntarily. A total of 443 valid questionnaires were collected through the Questionnaire Star application. The average age of the participants was 18.77 years old, with 157 males and 286 females. Statistical analysis was conducted using SPSS and AMOS.Results(1) Chinese college students’ online game addiction negatively affected their behavioral, emotional, and cognitive engagement (the three dimensions of learning engagement); (2) behavioral, emotional, and cognitive engagement negatively affected their reduced academic achievement motivation; (3) learning engagement mediated the relationship between online game addiction and reduced academic achievement motivation

    Molecular Cloning and Response to Water Temperature and Nutrient Manipulation of Insulin-like Growth Factor (IGF) Genes in Golden Pompano Trachinotus ovatus (Linnaeus 1758) Larvae

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    In this study, insulin-like growth factor I (IGF I) and IGF II in golden pompano larvae were cloned and analyzed. In the first trial, IGF expression during ontogeny of larvae in the first 18-days of their life was explored, and then the response of IGFs to water temperature (23, 26, and 29oC) on 12 day post hatching (DPH) and 18 DPH were compared. On 28 DPH, the response of IGFs to the manipulation of nutrients was evaluated. The expression of IGF I increased with the increase of fish age, and was not significantly affected by water temperature. The expression of IGF II was affected by water temperature on 12 DPH and 18 DPH. The expression of IGF II at 23oC was significantly higher than at 26oC and 29oC. The expression of IGFs in fish larvae on 28 DPH was not concomitant with nutrient manipulation. This study detected the gene expression of IGFs at the early stage of golden pompano larvae. The time dependent expression of IGF genes in fish larvae is important to understand the ontogenetic development and growth of fish larvae in early life

    Existence of Positive Solution for BVP of Nonlinear Fractional Differential Equation

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    We consider the following boundary value problem of nonlinear fractional differential equation: (CD0+αu)(t)=f(t,u(t)),  t∈[0,1],  u(0)=0,   u′(0)+u′′(0)=0,  u′(1)+u′′(1)=0, where α∈(2,3] is a real number,  CD0+α denotes the standard Caputo fractional derivative, and f:[0,1]×[0,+∞)→[0,+∞) is continuous. By using the well-known Guo-Krasnoselskii fixed point theorem, we obtain the existence of at least one positive solution for the above problem
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