Browsing by Publisher "Elsevier"
Now showing items 1-20 of 27
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Accretion flows in nonmagnetic white dwarf binaries as observed in X-rays
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Publisher and Date:(Elsevier, 2020)Cataclysmic Variables (CVs) are compact binaries with white dwarf (WD) primaries. CVs and other accreting WD binaries (AWBs) are useful laboratories for studying accretion flows, gas dynamics, outflows, transient outbursts, and explosive nuclear burning under different astrophysical plasma conditions. They have been studied over decades and are important for population studies of galactic X-ray sources. Recent space- and ground-based high resolution spectral and timing studies, along with recent ...
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An analysis of price spikes and deviations in the deregulated Turkish power market
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Publisher and Date:(Elsevier, 2019)The successful operation of a real time market is related to the planning in the day ahead market. We analyze the day ahead and real time market data for the Turkish power market for the period 2012-2015 to classify price spikes and their causes. We also focus on the levels of deviation between the day ahead market values and the real time market values. We define price deviation and load deviation ratios to measure the level of deviation both in price and demand. The analysis for the load is based ...
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Assortment optimization with log-linear demand: Application at a Turkish grocery store
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Publisher and Date:(Elsevier, 2019)In retail sector product variety increases faster than shelf spaces of retail stores where goods are presented to consumers. Hence assortment planning is an important task for sustained financial success of a retailer in a competitive business environment. In this study we consider the assortment planning problem of a retailer in Turkey. Using empirical point-of-sale data a demand model is developed and utilized in the optimization model. Due to nonlinear nature of the model and integrality ...
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Characterization of MWCNT-TiO2 Qps and TiO2 QDs in self-assembled films
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Publisher and Date:(Elsevier, 2017)In this study the solution which includes TiO2 quantum dots (QDs) was mixed with the multi-wall carbon nanotubes (MWCNTs) to prepare MWCNT-TiO2 QDs composite films. The effect of microstructures on the structural and optical properties of MWCNT-TiO2 QDs composite films was evaluated. The activation energy for crystallite growth of TiO2 QDs which are produced in brookite phases was calculated as 20.3 kJ/mol. The properties of MWCNT-TiO2 QDs composite films were characterized by X-ray diffraction ...
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Corporate risk-taking in developed countries: The influence of economic policy uncertainty and macroeconomic conditions
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Publisher and Date:(Elsevier, 2020)Using 74,974 firm-year observations covering 15 developed European countries over the time period 1999-2017, this paper explores the effect of economic policy uncertainty on corporate risk-taking. The findings indicate that firms become more risk averse with an economic policy uncertainty shock. The relationship is valid under idiosyncratic and earnings volatility risk measures, regardless of whether the macroeconomic condition is favorable or not. Moreover, the competition level in the industry ...
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Discovery of new azoles with potent activity against Candida spp. and Candida albicans biofilms through virtual screening
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Publisher and Date:(Elsevier, 2020)Systemic candidiasis is a rampant bloodstream infection ofCandidaspp. andC. albicansis the majorpathogen isolated from infected humans. Azoles, the most common class of antifungals which sufferfrom increasing resistance, and especially intrinsically resistant non-albicans Candida(NAC) species, actby inhibiting fungal lanosterol 14a-demethylase (CYP51). In this study we identified a number of azolecompounds in 1-(2,4-dichlorophenyl)-2-(1H-imidazol-1-yl)ethanol/ethanone oxime ester structurethrough ...
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Efficiency analysis of emergency departments in metropolitan areas
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Publisher and Date:(Elsevier, 2019)The demand in the healthcare industry is increasing exponentially due to aging population of the world and this is leading to a rapid increase in the cost of healthcare. The emergency departments of the hospitals are the frontline of health care systems and play an additional critical role in providing an efficient and high-quality response for patients. The overcrowding at the emergency departments due to growing demand results in a situation where the demand for ED services exceeds the ability ...
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Efficiency analysis of emergency departments in metropolitan areas
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Publisher and Date:(Elsevier, 2020)The demand in the healthcare industry is increasing exponentially due to aging population of the world and this is leading to a rapid increase in the cost of healthcare. The emergency departments of the hospitals are the frontline of health care systems and play an additional critical role in providing an efficient and high-quality response for patients. The overcrowding at the emergency departments due to growing demand results in a situation where the demand for ED services exceeds the ability ...
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Energy efficient robust scheduling of periodic sensor packets for discrete rate based wireless networked control systems
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Publisher and Date:(Elsevier, 2020)Wireless networked control systems (WNCSs) require the design of a robust scheduling algorithm that meets the stringent timing and reliability requirements of control systems, despite the limited battery resources of sensor nodes and adverse properties of wireless communication for delay and packet errors. In this article, we propose a robust delay and energy constrained scheduling algorithm based on the exploitation of the mostly pre-known periodic data generation nature of sensor nodes in control ...
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Forecasting electricity demand for Turkey: Modeling periodic variations and demand segregation
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Publisher and Date:(Elsevier, 2017)In deregulated electricity markets the independent system operator (ISO) oversees the power system and manages the supply and demand balancing process. In a typical day the ISO announces the electricity demand forecast for the next day and gives participants an option to prepare offers to meet the demand. In order to have a reliable power system and successful market operation it is crucial to estimate the electricity demand accurately. In this paper we develop an hourly demand forecasting method ...
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Hourly electricity demand forecasting using Fourier analysis with feedback
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Publisher and Date:(Elsevier, 2020)Whether it be long-term, like year-ahead, or short-term, such as hour-ahead or day-ahead, forecasting of electricity demand is crucial for the success of deregulated electricity markets. The stochastic nature of the demand for electricity, along with parameters such as temperature, humidity, and work habits, eventually causes deviations from expected demand. In this paper, we propose a feedback-based forecasting methodology in which the hourly prediction by a Fourier series expansion is updated ...
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Identification of potential inhibitors of human methionine aminopeptidase (type II) for cancer therapy: Structure-based virtual screening, ADMET prediction and molecular dynamics studies
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Publisher and Date:(Elsevier, 2020)Methionine Aminopeptidases MetAPs are divalent-cofactor dependent enzymes that are responsible for the cleavage of the initiator Methionine from the nascent polypeptides. MetAPs are classified into two isoforms: namely, MetAP1 and MetAP2. Several studies have revealed that MetAP2 is upregulated in various cancers, and its inhibition has shown to suppress abnormal or excessive blood vessel formation and tumor growth in model organisms. Clinical studies show that the natural product fumagillin, and ...
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Managing natural gas demand for free consumers under uncertainty and limited storage capacity
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Publisher and Date:(Elsevier, 2020)Demand for energy sources depends on several factors such as population growth, urbanization, industrialization, and climate. Among fundamental energy sources, natural gas is characterized by storage limitations and take-or-pay contracts, which makes it especially critical to forecast the demand accurately for cost management policies. Suppliers of natural gas require take-or-pay contracts to ensure that consumers pay for any unused amount up front; and if the demand exceeds the agreed amount, ...
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Measuring energy intensity in Japan: A new method
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Publisher and Date:(Elsevier, 2017)Energy intensity and energy conservation have been important pillars of energy policies in Japan. Recently the government has introduced new initiatives to enhance energy efficiency and reduce energy intensity. We analyze the energy intensity in Japan for the period 1973-2006 by proposing a new method which takes into account all other inputs used in production and corrects for the bias in the traditional energy intensity measure. We show that the traditional energy intensity measure has serious ...
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Models for relief routing: Equity efficiency and efficacy
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Publisher and Date:(Elsevier, 2011)In humanitarian relief operations vehicle routing and supply allocation decisions are critically important. Similar routing and allocation decisions are studied for commercial settings where efficiency in terms of minimizing cost is the primary objective. Humanitarian relief is complicated by the presence of multiple objectives beyond minimizing cost. Routing and allocation decisions should result in quick and sufficient distribution of relief supplies with a focus on equitable service to all aid ...
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Multidirectional Relationship between Energy Resources, Climate Changes and Sustainable Development: Technoeconomic Analysis
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Publisher and Date:(Elsevier, 2020)Global changes in temperature will likely change energy use and electricity production capacity. Considering the relationship between climate change and energy resource use, changes in temperature and the frequency and intensity of extreme events will affect how much energy is produced and consumed. The green economy and green growth are located at the heart of the fight against climate change in creating sustainable development. This paper considers the multidirectional relations between climate ...
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Ontology-based data acquisition model development for agricultural open data platforms and implementation of OWL2MVC tool
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Publisher and Date:(Elsevier, 2020)In the open data world, it is difficult to collect data in compliance with a certain data model that is of interest to different types of stakeholders within a domain like agriculture. Ontologies that provide broad vocabularies and metadata with respect to a given domain can be used to create various data models. We consider that while creating data acquisition forms to gather data related to an agricultural product, which is hazelnut in this study, from stakeholders of the relevant domain, the ...
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Perception, petroleum, and power: Mythmaking in oil-scarce Turkey and Jordan
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Publisher and Date:(Elsevier, 2020)Oil has been a cardinal driver of economic growth and national development in the twentieth and twenty-first centuries. States that produce oil in globally exportable quantities tend to be more powerful than those that do not. Oil-scarce states in the Middle East that neighbor oil-rich states and rely on them for imports create myths to explain their relatively unfortunate geology. This study illustrates and analyzes the myths that people in Turkey and Jordan have created to explain why they lack ...
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Political turmoil and the impact of foreign orders on equity prices
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Publisher and Date:(Elsevier, 2020)This paper examines whether foreign investors possess an information advantage over local investors in the Turkish stock market between 2007 and 2015. We find that foreign investors have an information advantage in 24 stocks, corresponding to seven percent of the sample firms. Foreign investors' information advantage tends to prevail primarily during a period of political instability, which started with the Gezi Park protests in June 2013. The adverse selection component of the foreign trade ...
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Posterior vitrectomy under topical anesthesia
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Publisher and Date:(Elsevier, 2007)Background: To determine the safety and efficacy of topical anesthesia in posterior vitrectomy. Methods: A total of 93 patients (93 eyes) with various vitreoretinal diseases not needing scleral buckling and with short predicted duration of surgery underwent posterior vitrectomy under topical (49 eyes) or retrobulbar (44 eyes) anesthesia. Patients in the topical group were sedated with neuroleptic anesthesia. Postoperatively patients were shown a visual analogue pain scale (VAPS) from 0 (no pain) ...
