235 research outputs found
Predicting Audit Opinion by a new Metaheuristic Algorithm: Water Cycle Algorithm
An auditor evaluates if financial statements which the firms issue in public, present fairly and are free from material misstatement. The audit report is a written letter containing independent verification of the quality of financial statements used for making economic decisions. Hence, the issuance of such a report can lead to the transmission news and information about the firm and to enhance the degree of confidence in the financial statements. This study predicts audit opinion of the firms listed in Tehran Stock Exchange during 2018-2020 by a new metaheuristic algorithm named Water Cycle Algorithm (WCA) and compares its results with one of the most popular methods called logistic regression (LG). 24 variables were extracted from the literature and used for this prediction. 4 evaluating criteria were used to compare the predictions of two methods. According to findings, the superiority of the criteria in the WCA was confirmed in comparison to LG. Since WCA was more appropriate, users of financial reports can use it to predict the type of audit opinion in the unaudited interim financial statements, and also, auditors can use it while evaluating and accepting clients and achieving an acceptable level of audit risk, as a quality control tool
An Improved Under-Frequency Load Shedding Scheme in Distribution Networks with Distributed Generation
When a distribution network consisting of Distributed Generations (DGs) is disconnected from upstream network, the system may be exposed to severe power imbalance. In order to prevent the damage of power plants, frequency relays operate and remove DGs from the network. In contrast to traditional methods, the main objective in new methods is to keep DG units in service in the islanded distribution system. Under-Frequency Load Shedding (UFLS) is one of the most important protection systems, which is the last chance for avoiding a system blackout following severe disturbance. This paper dealt with an adaptive UFLS method and considered the priority of loads to be shed, depending on the intensity of event, and loads look up table built by Rate of Change of Frequency of Loads (ROCOFL) indices based on the frequency of centre of inertia (fCOI). Different loads were shed depending on the event type diagnosed by measuring the initial Rate of Change of Frequency (ROCOF) in the method. The proposed UFLS method can stabilize the frequency of the distribution system in islanding mode by shedding sufficient loads. The simulation results confirmed the advantages of the methods in comparison to other proposed algorithms
Facile synthesis and characterization of CeMoO4 nanostructure via co-precipitation method and investigate its application supercapacitor
Abstract- Here in, CeMoO4 nanostructure were successfully prepared by a co-precipitation route without capping agent. The characterization and morphological of as-prepared samples were examined by Fourier transform infrared spectroscopy, filed emission scanning electron microscopy, X-ray diffraction, and energy dispersive X-ray spectroscopy. SEM and XRD results show that CeMoO4 nanostructure obtained with average nano-plate thickness 30 nm and average crystal size of 10 nm. The evaluations on CeMoO4-based electrodes revealed the material to have a specific capacitance (SC) of 327 F g�1 at a scan rate of 2 mV s�1, an energy density of 24.5 W h kg�1, and a high rate capability. Continues cyclic voltammetry evaluations using CeMoO4-based electrodes proved the electrodes to be capable of maintaining almost 96.3 of its initial SC after 4000 cycles. To the best of our knowledge, this study is considered as the start point of using lanthanide molybdates as an electrode materials for supercapacitors and the results obviously consent to outstanding properties of CeMoO4 for the mentioned application. © 2019 by CEE (Center of Excellence in Electrochemistry
Synthesis and characterization of nickel molybdate nano-powders in the presence of carboxymethyl cellulose as a new capping agent and its application on electrochemical determination of ethanol
Nickel molybdate (NiMoO4) nanopowders were prepared by a new method in low temperature. For the first time, we used carboxymethyl cellulose as a new capping agent in synthesis procedure. The formed nickel molybdate products have been characterized by means of UV�vis diffuse reflectance spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray microanalysis (EDX). Glassy carbon electrode modified with NiMoO4 nanopowders was prepared and used for oxidation of ethanol and methanol. The study of the different scan rates indicates a diffusional process for oxidation of ethanol. The detection limit obtained for ethanol was also 3.8 mM. © 2019 by CEE (Center of Excellence in Electrochemistry)
Anti-inflammatory and immune-modulatory impacts of berberine on activation of autoreactive T cells in autoimmune inflammation
Autoreactive inflammatory CD4+ T cells, such as T helper (Th)1 and Th17 subtypes, have been found to associate with the pathogenesis of autoimmune disorders. On the other hand, CD4+ Foxp3+ T regulatory (Treg) cells are crucial for the immune tolerance and have a critical role in the suppression of the excessive immune and inflammatory response promoted by these Th cells. In contrast, dendritic cells (DCs) and macrophages are immune cells that through their inflammatory functions promote autoreactive T-cell responses in autoimmune conditions. In recent years, there has been increasing attention to exploring effective immunomodulatory or anti-inflammatory agents from the herbal collection of traditional medicine. Berberine, an isoquinoline alkaloid, is one of the main active ingredients extracted from medicinal herbs and has been shown to exert various biological and pharmacological effects that are suggested to be mainly attributed to its anti-inflammatory and immunomodulatory properties. Several lines of experimental study have recently investigated the therapeutic potential of berberine for treating autoimmune conditions in animal models of human autoimmune diseases. Here, we aimed to seek mechanisms underlying immunomodulatory and anti-inflammatory effects of berberine on autoreactive inflammatory responses in autoimmune conditions. Reported data reveal that berberine can directly suppress functions and differentiation of pro-inflammatory Th1 and Th17 cells, and indirectly decrease Th cell-mediated inflammation through modulating or suppressing other cells assisting autoreactive inflammation, such as Tregs, DCs and macrophages. © 2020 The Authors. Journal of Cellular and Molecular Medicine published by Foundation for Cellular and Molecular Medicine and John Wiley & Sons Lt
Economic and social assessment of fish farming in cages in the southern Caspian Sea
This study aimed to assess the social, economic and fish farming in cages in the Southern Caspian Sea. The Caspian Sea is considered as one of the most important water resources of Iran, in which due to the appropriate weather conditions in the north of the country, has the potential for marine aquaculture. With the implementation of this plan would say that with respect to the proposed initial selection from Kheshtsar in Mazandaran province and Kiashahr in Guilan province with along coastline of about 250 km from the depth of 20 to 100 meters and an the area of about 2027km^2 has the cage aquaculture talent. Of course, at the depths of greater than 100 M by using the world technology procedure, there is also the possibility of the establishment of marine cage aquaculture. Now, with the regards of the above potential in the Caspian Sea coastline, it is expected at least 200 cages fish sites farming in with the establishment of 40 cages per site and produce 160,000 tons with creating of 1,000 direct jobs and 2,000 indirect jobs and income 2000 billion gross annual average net profit of 40% could be 800 billion in which will produce of proteins needed part of the country, creating jobs, welfare, prosperity and economy in the region. With the implementation of such national project, it is needed to establish pilot farms to reach the goals: environmental assessment studies, risk assessment, aquatic selection and the use of appropriate cage structures according to ecological conditions of southern Caspian Sea
Adaptive antenna selection and Tx/Rx beamforming for large-scale MIMO systems in 60 GHz channels
We consider a large-scale MIMO system operating in the 60 GHz band employing beamforming for high-speed data transmission. We assume that the number of RF chains is smaller than the number of antennas, which motivates the use of antenna selection to exploit the beamforming gain afforded by the large-scale antenna array. However, the system constraint that at the receiver, only a linear combination of the receive antenna outputs is available, which together with the large dimension of the MIMO system makes it challenging to devise an efficient antenna selection algorithm. By exploiting the strong line-of-sight property of the 60 GHz channels, we propose an iterative antenna selection algorithm based on discrete stochastic approximation that can quickly lock onto a near-optimal antenna subset. Moreover, given a selected antenna subset, we propose an adaptive transmit and receive beamforming algorithm based on the stochastic gradient method that makes use of a low-rate feedback channel to inform the transmitter about the selected beams. Simulation results show that both the proposed antenna selection and the adaptive beamforming techniques exhibit fast convergence and near-optimal performance
Comparison of intramedullary and extramedullary fixation of stable intertrochanteric fractures in the elderly: a prospective randomised controlled trial exploring hidden perioperative blood loss
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